75 /—- wet/C 3.13 V Paleozoic Rocks of Antelope Valley Eureka and Nye Counties Nevada ,4 f". ‘4 , «a . W 4/” ~§ !/ a v ,. ‘4 v I w; .‘n s. ,4 3/ - t" ,1 A. V“ f; ,1 '3 / L‘ .A r e ”I'll-l SCIENCES LIBRARY Paleozoic Rocks of Antelope Valley Eureka and Nye Counties Nevada By CHARLES W. MERRIAM GEOLOGICAL SURVEY PROFESSIONAL PAPER 423 Princzpley ofstratigrapny applieaI in a’excrzpti‘ve ytaa’y of t/ze Central Great Basin Paleozoic column UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1963 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director ;’ // 1’14 X ’. ‘./’ For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, DC. QEvs Fe CONTENTS SClENCES LEERAZY Page Abstract ........................................... 1 Silurian system _____________________________________ Introduction ....................................... 2 General features ________________________________ Geologic setting ________________________________ 2 Roberts Mountains formation _________ ‘ ___________ History of investigation _________________________ 5 Lone Mountain dolomite ________________________ Purpose and scope ______________________________ 6 Devonian system ................................... Acknowledgments _______________________________ 6 General features ________________________________ Geologic structure as related to stratigraphy ___________ 6 Western Helderberg age limestones of the Monitor Paleontologic studies ________________________________ 9 Range _______________________________________ The Paleozoic column at Antelope Valley ______________ 12 Rabbit Hill limestone _______________________ Cambrian system ____________________________________ 14 Normal western sequence Devonian rocks of Antelope General features________-_-; ________ L ___________ 14 Valley _______________________________________ Windfall formation .............................. 14 Nevada formation __________________________ Ordovician system __________________________________ 16 Devils Gate limestone _______________________ General features ________________________________ 16 Strata of Late Devonian and Early Mississippian age- - _ Ordovician system boundaries ____________________ 16 Film; shale- - - - - - - - - .- - -: ------------------------ Facies problems ________________________________ 17 Lower part of the Pilot shale ................. Pogonip group_-_____--_--_-_______’ _____________ 17 Upper Paleozorc rocks ........................ . ....... Goodwin limestone __________________________ 19 Genera! fegtures““'"""""""_ """"""" Ninemile formation 22 Mississ1pp1an rocks """"""""""""""""""" , """"""""""""" Chainman shale and Diamond Peak formation, Antelope Valley hmestone ................... 23 undifferentiated __________________________ Copenhagen formation- - _‘ _______________________ 25 Permian systgm __________________________ ' ______ Eureka quartzite ------------------------------- 27 Garden Valley formation ____________________ Hanson Creek formation _________________________ 31 Locality register ____________________________________ Western facies rocks of Ordovician age ____________ 33 References cited ____________________________________ Vinini formation ____________________________ 33 Index _____________________________________________ ILLUSTRATIONS [Plates are in pocket] Purl 1. Geologic reconnaissance map, northern half Antelope Valley area. 2. Geologic reconnaissance map, southern half Antelope Valley area. FIGUIE 1. Index map showing location of the Antelope Valley area __________________________________________________ 2. Index map of central and eastern Nevada _______________________________________________________________ 3. Section along line B—B’ south of Ninemile Canyon, Antelope Range, showing Ordovician formations ___________ 4. Section along line A—A’ at Copenhagen Canyon, Monitor Range, showing thrust relationship of rocks of the OI Tum l. Pogonip group over Lower Devonian Rabbit Hill limestone ............................................. . Section along line C—C” at Ninemile Canyon, Antelope Range, showing Upper Cambrian and Ordovician forma- tions _____________________________________________________________________________________________ Correlation diagram showing possible age relationship of Ordovician rocks of Eureka and Antelope Valley, Nevada, to those of described sections in Utah ________________________________________________________________ . Correlation diagram showing possible age relationships of Ordovician, Silurian, and Lower Devonian rocks in the Antelope Valley area _______________________________________________________________________________ . Correlation diagram showing probable age relationships of Devonian strata in the Antelope Valley and Eureka areas, Nevada _____________________________________________________________________________________ TABLES Normal stratigraphic section at Antelope Valley, Nev ____________________________________________________ . Cmparison of normal western sequence of the Nevada formation with the eastern sequence .................. m 201 v. (GE-431}: /$ EARTH Page 36 36 37 39 41 41 42 42 44 44 49 56 56 56 56 56 57 18 28 52 Pm 13 45 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA “ AND NYE COUNTIES, NEVADA By CHARLES W. MERRIAM ABSTRACT Antelope Valley is bordered by mountains of the Basin and Range Province that consist mainly of Paleozoic strata partly covered by Cenozoic volcanic rocks. The Paleozoic beds range in age from Late Cambrian to Early Permian; only the Pennsyl— vanian system is unrecognized. Reconnaissance geologic mapping in the 1-degree Roberts Mountains quadrangle pointed up need for special studies of stratigraphy and paleontology relating principally to the Ordo- vician, Silurian, and Devonian systems. Widespread thrusting coupled with later normal faulting so complicates stratigraphic study in this region that a simul- taneous approach to problems of stratigraphy and structural geology is needed. To achieve a more comprehensive regional understanding of areal, stratigraphic, and structural relations, the Antelope Valley investigations were coordinated with work in the adjoining Eureka mining district. Impressive manifestations of intense defamation are thrust outliers of Ordovician beds of the Vinini formation. These outliers rest upon Paleozoic rocks of different facies and range in age from Ordovician to Carboniferous. It has become reason- ably certain that the graptolitic rocks were deposited in a west- ern Great Basin depositional subprovince, whereas the pre-. Carboniferous rocks over which they have been thrust accumu- lated in an eastern subprovince wherein carbonate sedimenta- tion predominated. Immense horizontal displacement is clearly related to the Roberts Mountains thrust, earlier described in the region to the north. Thrusts of lower magnitude in the Monitor and Antelope ranges are possibly sympathetic to the main Roberts Mountainl thrust. Aside from the major facies changes of subprovincial mag- nitude, well-marked east-west difi’erences are recognized within Ordovician, Silurian, and Devonian rocks of the eastern or carbonate subprovince itself. or 17 Paleozoic formations described in this report 14 are normally superposed at Antelope Valley. These range from Late Cambrian to Mississippian. The Ordovician is the most diverse in terms both of rock type and faunas. Twelve of the normal section formations at Antelope Valley are present also at Eureka, but the facies of several of these differ markedly. Paleontologic research undertaken in conjunction with the stratigraphy was confined largely to preliminary identification of diagnostic fossils. Another major consideration in which fossils have played the significant role is that of system— boundary definition, which remains somewhat arbitrary. More detailed studies of the Helderberg and Oriskany Early Devonian faunas were also carried forward as part of this program. Only a single unit of Cambrian age, the Windfall formation, is expOsed at Antelope Valley. This Late Cambrian unit lacks the upper member of the type section near Eureka, and is over- lain by dark carbonaceous shale containing only the small crustacean Oaryocar-is. The normal Ordovician column including six formations is about 4,300 feet thick. Ranging in age from Early to Late Ordovician (Richmond), these units are in order from bottom to top as follows: Goodwin limestone, Ninemile formation, Antelope Valley limestone, Copenhagen formation, Eureka quartzite, and Hanson Creek formation. Limestones predomi- nate, but the Eureka quartzite is a notable exception. Three of these Ordovician formations—Ninemile, Antelope Valley, and Copenhagen—have type sections in the Antelope Valley area. The richly fossiliferous Copenhagen, theoretically a facies of the lower part of the Eureka, is known only in the study area. Thrust outliers of Ordovician graptolite shale, bedded chert, and sandstone occur in the northern Mahogany Hills, at the north end of Monitor Range, and in the vicinity of Charnac Basin. Where fossils are absent, these shales and sandstones of the Vinini are easily confused with similar beds of Carbonif- erous age. The rocks of the Silurian system, about 2,200 feet thick, in- clude the Roberts Mountains formation below and the Lone Mountain dolomite above. Limestone of the Roberts Moun- tains formation carries a Monograptus fauna in the Monitor Range; its base is there defined by a laterally persistent cherty zone. This formation changes to dolomite on the east side of Antelope Valley, where it is gradational above with the Lone Mountain dolomite. In the Monitor Range, where the Lone Mountain is unrecognized, the Monograptua beds are seemingly overlain disconformably by Early Devonian (Helderberg) Rab- bit Hill limestone. Silicified fossils, including the Late Silurian brachiopod Howellella, occur in the upper part of the Lone Mountain dolomite. These beds are disconformably overlain by Oriskany age Lower Devonian dolomitic limestone of the Nevada on the east side of Antelope Valley. Devonian rocks of this area, about 4,000 feet thick, range in age from Helderberg to Late Devonian and are classified in four formations; only three of them—the Nevada, the Devils Gate, and the lower part of the Pilotware superposed in a continuous section. The Rabbit Hill limestone seems to be con- fined to the west, where it occurs in the Monitor Range. On the contrary the Nevada formation of Early and Middle De- vonian age and the Devils Gate limestone of late Middle and Late Devonian age are found only on the east and are not recognized on the Monitor Range side of the valley. The Nevada formation has been zoned paleontologically and is subdivided lithologically into lower, middle, and upper'divi- sions. Oriskany age spirifers of the arenosa and murchisoni types characterize the lowest zone, whereas the upper zone carries Stringocephalus and is of late Middle Devonian age. The Nevada changes lithologically and to some extent faunally eastward from Antelope Valley to the Eureka district, where it is divisible into five members. With the facies change east- ward, the rich lower Nevada faunas disappear. . 1 2 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA The upper Nevada Stringocephalus fauna does not extend into the overlying Devils Gate limestone, which is lithologically more uniform than the Nevada. Late Devonian faunas of the upper part. of the Devils Gate include Pachyphyllwm, Mantico- came, Hypothyridina emmonsi (Hall and Whitfield), and Oyrtospim'fcr. Gradationally above the Cyrtospirifer zone is the lower part of the Pilot shale hearing a Late Devonian conodont assemblage. Mississippian shales and sandstones of Antelope Valley are classed as Chainman shale and Diamond Peak formation, un— differentiated. Closely associated with them in the northern Mahogany Hills are similar rocks of the overthrust Ordovician Vinini formation. Ely limestone of Pennsylvanian age, present in the vicinity of Eureka, was not recognized at Antelope Valley. Upperth Paleozoic rocks of the area are assigned to the Garden Valley formation of Wolfcamp Permian age. These beds appear to rest unconformably upon over-thrust graptolite shale in the northernmost Monitor Range. Two divisions are described, a lower fossiliferous sandy and pebbly limestone and a much thicker limestone cobble conglomerate. Cohbles in this unit contain Ordovician fossils of the Pogonip group. INTRODUCTION GEOLOGIC SETTING Nowhere in western North America are fossil—bearing middle Paleozoic rocks better shown than at Antelope Valley and in adjoining territory of Eureka and Nye Counties, Nev. (fig. 1). Within this area, situated north of parallel 39 and west of the important Eureka mining district, marine rocks of Ordovician, Silurian, and Devonian ages have a combined thickness of more than 10,000 feet. Strata of Late Cambrian, Carbonif- erous, and Permian ages are likewise present; but be- cause they have a more restricted distribution, they can be studied to greater advantage in neighboring areas. Antelope Valley has the north-south trend character- istic of the Great Basin. The valley is V-shaped and is formedby divergence of the Antelope Range on the east from the Monitor Range on the west. Antelope Range ends without completing the east arm of the V; to the north, beyond its tip, the adjacent Fish Creek Range swings northeastward to join the mountains that en- close Antelope Valley with those of the Eureka district. Antelope Valley opens into a broad almost quadrang- ular basin known as Kobeh Valley, north of which lie the Roberts Mountains (fig. ‘2). Lone Mountain, with its unexcelled exposures of Ordovician, Silurian, and Devonian rocks, rises like an island near the margin of Kobeh Valley, a short distance northeast of its union with Antelope Valley. Except for scattered small playas, the alluvial flats of the valley floor are clothed with sparse semidesert vege— tation. Characteristic plants are greasewood, rabbit- brush, sage, white sage, and shadscale. Gentle sage- mantled slopes rise from the broad flats on either side to meet coalescent fans, with here and there an interven- ing pediment surface. At the valley edge there is abrupt change in acclivity where mountains character- istic of the Basin and Range Province rise as much as 4,000 feet above the valley floor. Summit Mountain and Antelope Peak in the northern Monitor Range reach 10,461 and 10,220 feet. respectively.‘ These mountains, which are the highest in the area, consist of volcanic materials. The Mahogany Hills, Fish Creek Range, and Antelope Range to the east are composed largely of Paleozoic sedimentary rocks. Like the loftier Monitor Range to the west, they are clothed with forests typical of the central Great Basin comprising juniper, pinyon pine, and mountain mahogany. The northern Monitor Range is within a belt of in- tense Tertiary vulcanism, and volcanic rocks cover most of the Paleozoic strata in this part of the Antelope Val- ley area (pl. 1). Well displayed in Summit Mountain and Antelope Peak is a succession of rhyolite, dacite and andesitic flows, together with tufl's and coarser pyro- clastic rocks; the entire volcanic pile is about 4,000 feet thick. At Bald Mountain and Charnac Basin water-laid tufl'aceous sediments contain fossil floras of undeter- mined age. Volcanic rocks have been completely eroded from the Twin Spring Hills on the north, where Per— kmian and Ordovician strata are exposed. Volcanic cover has also been eroded from an area southeast of Charnac Basin, where much significant evidence on the Ordovician, Silurian, and Devonian systems was obtained. The Paleozoic rocks are largely devoid of volcanic cover on the Antelope Range side of the valley, where outcrops of Paleozoic strata continue south through the Mahogany Hills and western Fish Creek Range. Across Fenstermaker Wash they extend south in the Antelope Range to meet partial volcanic cover at Ninemile (,‘anyon. ' Fresh-water" Cretaceous sediments of the Newark Canyon formation (Nolan, Merriam, and Williams, 1956, p. 68) occupy a saddle on the northwest spur of Table Mountain, where they rest upon massive Devils Gate limestone (10c. 71). This small erosion remnant comprises yellowish gray, tan, and reddish sandstone, siltstone, and plant—bearing shale beds. “'esternmost exposure of this unit thus far recognized is in the Twin Spring Hills (10c. 91) of the Monitor Range, where it. rests unconformably upon the Permian Garden Valley formation. F anglomerate, gravel, sand, diatomaceous deposits, and volcanic ash compose the later deposits of Antelope Valley. \Vhite, poorly consolidated sand, silty and shaly diatomaceous beds, and loose white volcanic ash ‘ Altitudes from Antelope Park quadrangle, 1956; altitudes shown on pl. 1 are from Roberts Mountains quadrangle of 1929. INTRODUCTION ”2" '2", '2.°° “.9" ”8° ”7° “6° “4° “3° ' l | 1 | | ___,___ __.-—r' 42°- 4 l°- o Wells 40'— 39°- . Round Mountain 0 Bolmont u 0 Mmhoflon ° Tybo 38°— \Tonopah .iGoldfield I ! 35°‘ I r— . L...— 34°J 50 MILES FIGURE 1.—Index map showing location of the Antelope Valley area (A) and the Roberts Mountains Quadrangle, Nevada (B). 4 PALEOZOIC ROCKS OF ANTELOPE VALLEY‘ EUREKA AND NYE COUNTIES, NEVADA 117° ‘ 116' ' V 115' 114' 41° 0 m .‘L 8 r PILOT R‘NGE _-——__._—-_—_ HUMBOLDT RANGE TOANA MOUNTAINS d‘ O 1 O L ‘5 _ A > '0 n l 1—" if 0 I BAl'rLE CD! 1; I > MOUNTAINS Snmcelm “J n. z 0 / m . O Hilltop / Mt Lawns LANDER - DIAMSND mou TAINS ROBERTS MOUNTAINS DUADRANGLE 32 OTonkin Rnherts Sleek Min 0 6 Bald PM" g. i i ____ __L-———-——-— X PHILLIPSBURG MIN: ‘0 Strawberry >. 2 E Diamond Peak “Naval: Ml" W H I T I t . wan; 2 a" Charnac g g, Bellevue Puk o Basin 3' Belmont. Mill n X 5 ;ca :14 MlHamiltélnooHamilton Rm] 5 .. I: M uc‘w "’ ’ 5° 5 3 0 0 on us lmsnye Peak 4—; 3"" lu E in o <2 2 I41 2 u \w §\ \ I I l 4 Wheeler Peak “ i i q z I lu 0’ I uckwater I O Shoshone (I) o R on umnt 2 I ~ _ —— — —-— - —-‘I (J OCave V-lley m uh; I20 N O 20 MILESI l—-L__l—L_._l.—_I \l u l FIGURE 2.—-Index map of central and eastern Nevada showing localities to which reference 13 made. INTRODUCTION 5 are well shown on the lower southwest and east slopes of Lone Mountain. At Lone Mountain the flat-lying white beds are at least 160 feet thick. Poor exposures of these strata are found northeast of the Twin Spring Hills, on the northwest side of Mahogany Hills, and at many places along the east side of Antelope Valley south to Fenstermaker Wash. Whether these diato- mite and ash beds are partly late Tertiary or entirely Pleistocene has not been determined. In any case Antelope Valley undoubtedly held a southerly arm of Kobeh Valley Lake in Pleistocene time. Geomorphically the mountains surrounding Ante- lope Valley are representative of the Basin and Range Province, as they are bounded for the most part by en echelon frontal faults. In fact the linear west front and abrupt rise of the Antelope Range clearly indicate the faultline influence. In the Devonian rocks at the northwest tip of this range, there is clear stratigraphic evidence of valley-side down throw on northeastward» striking normal faults near the valley edge (pl. 2). HISTORY OF INVESTIGATION Attention was first drawn to Paleozoic rocks of the Antelope Valley area by Henry Englemann, geologist and meteorologist of the Simpson Exploring expe- dition that crossed Kobeh Valley (“Kobah Valley”) in 1859. Accordingtothe published route map (Simpson, 1876), the explorers skirted Lone Mountain (“Lowry Peak”) on the south and followed Devils Gate Pass (“Swallow Canyon”) to Diamond Valley (“Pah-hun- nupe Valley”). Englemann was especially attracted by the impressive exposures of Devils Gate limestone, from which Devonian fossils later identified by Meek (Meek and Englemann, 1860; Meek, 1876) were col— lected. ' In the decade following 1868, the Geological Survey of the Fortieth Parallel examined and reported upon the Paleozoic rocks of neighboring areas, principally to the north but also east and west of Antelope Valley. Mountains stretching northward from the Mahogany Hills were at that time referred to as the “Pinyon Range.” Although the richly fossiliferous rocks at Devils Gate were known to the Fortieth Parallel party (King, 1878, p. 211), most of the Devonian fossils col- lected by them in the “Pinyon Range” appear to have come from farther north, in that part today called the Sulphur Spring Mountains (fig. 2) . In 1880 and 1881 the rocks on the east side of Ante— lope Valley extending south from Devils Gate (“The Gate”) through Wood Cone and Bellevue Peak were mapped by the US. Geological Survey party under Arnold Hague (1883; 1892). Walcott (1884) at that time investigated the stratigraphy and faunas of the mapped area with special reference to Upper Devonian rocks at Devils Gate, Middle Devonian at Combs Peak, and the Upper Ordovician near Wood Cone. Ordovician and Devonian collections from nearby Lone Mountain made by Walcott and other members of the Hague party provided an important part of the mate- rial described and figured in the Eureka paleontology memoir (Walcott, 1884). For 50 years the mono— graphic studies by Hague and Walcott remained the most significant references‘on Paleozoic history and paleontology of the Great Basin, in fact of the entire Far West. / Little was added to knowledge of Paleozoic rocks in Antelope Valley and the neighboring Eureka district until 1928, when Henry G. Ferguson and Edwin Kirk of the US. Geological Survey visited these areas for geologic reconnaissance and fossil collecting. Kirk (1933; 1934) later discussed some aspects of the fossil record in the northern Antelope and Monitor Ranges, calling especial attention to the Ordovician sections, which beginning with his visit, have yielded a rich store of fossil material. At the suggestion of Edwin Kirk, the Devils Gate and Lone Mountain sections were studied by Merriam (1940) and various stratigraphically significant Devo— nian fossils were described and figured. In 1939 and 1940, during the geologic investigations in the Roberts Mountains by Merriam and Anderson (1942), several Ordovician sections of Antelope Valley were visited in the hope of resolving local problems of stratigraphic correlation and geologic structure. Current study of Antelope Valley is in essence an outgrowth of these earlier geologic investigations of the Roberts Mountains 1—degree quadrangle initiated in 1939. The present. report embodies results of joint field- work undertaken near Martin Ranch by the writer in collaboration with C. M. Nevin and L. E. Nugent of Cornell University. A preliminary geologic map of Martin Ridge was contributed largely through the ef— forts of Nevin and Nugent during the summer of 1940. For brief periods in 1941, 1948, and 1950 the writer continued reconnaissance mapping and fossil collecting in the Antelope and Monitor Ranges. Revision of Paleozoic stratigraphy in the Eureka mining district was undertaken jointly in 1951 by T. B. Nolan, J. S. Williams, and the writer (Nolan, Merriam, and Williams, 1956). Several of the stratigraphic and related structural problems dealt with briefly in this contribution are common to the Eureka district and Antelope Valley. These questions have in recent years been investigated further by Nolan and the writer. Among them are Cambrian-Ordovician boundary rela- tions, phenomenal distribution of the Vinini graptolite 6 PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA shales, and westward facies change in the Ordovician, Silurian, and Devonian rocks. This paper was in substance largely completed by 1943, but before it was published new field evidence made revisions necessary, and the paper was therefore withheld until changes and adjustments could be made. Since 1945 growing interest in oil potentialities of the Great Basin has stimulated geologic activity. Con- sequently, the better exposed stratigraphic sections, including those in Antelope Valley and neighboring areas, have received attention from several oil compa- nies. The economic interest drew response likewise from academic institutions, with the result that stu- dents in growing numbers have been attracted to the many stimulating field problems the region offers. In response to requests by scientific colleagues for strati— graphic information on the central Great Basin region, ' much of what is herein embodied was made available before 1950. PURPOSE AND SCOPE The main objective of the present study, begun in 1940, is to continue southward the reconnaissance geo- logic mapping in the Roberts Mountains region initiated by Merriam and Anderson (1942). The Paleozoic sec- tions at Antelope Valley had previously been noted to differ appreciably from those at Eureka to the east and the Roberts Mountains to the north. These differences~ are best demonstrated by detailed comparative study and description of the Antelope Valley rocks and their ‘ contained fossil faunas. Scant geologic evidence from areas west of Antelope Valley indicates even more marked depositional changes in that direction, such as might be expected near the margin of a geosynclinal basin; this problem can best be attacked by first gain- ing as full an understanding as possible of the Antelope Valley rocks as a basis for extrapolation. A major objective of the Antelope Valley program is to provide a sound stratigraphic and paleontologic basis for future detailed geologic mapping and struct— ural study now in progress. Toward these ends, zoned fossil collections have been made from several of the formations, though much careful collecting remains to be done. These collections, it is hoped, will serve like— wise as a basis for more refined paleontologic studies, as noted under the section on “Paleontologic studies.” As in the Roberts Mountains (Merriam, 1940; Mer- riam and Anderson, 1942) very general reconnaissance mapping was done in selected parts of the Antelope Valley area. The base map used for this purpose is a two times enlargement of the 1: 250,000 Roberts Mountains quadrangle (pls. 1, 2). Several of the stratigraphic sections, which at the outset appeared relatively unbroken, were measured in detail with tape and Brunton compass. However, some thickness figures presented here must. be regarded as rough approxima— tions, having been scaled from reconnaissance maps in areas of strong deformation. Because of pervasive faulting, bed-by—bed measurement was in many sections found impracticable or unreliable. As in other parts of the Great Basin, detailed measuring of sections after preliminary areal mapping proved to be the most satisfactory method. ACKNOWLEDGMENTS The writer takes pleasure in acknowledging the en- couragement and friendly counsel given by Thomas B. Nolan. After a long period of pleasant association on problems of central Great Basin geology it became the writer’s privilege to collaborate with Nolan and James S. Williams on a revision of the stratigraphy of the Eureka district. Since the outset of this program, G. Arthur Cooper of the Smithsonian Institution has helped greatly by his advice on fossil identification, and geologic correla- tion, and by criticism of manuscript. The late Rudolf Ruedemann kindly identified Ordovician and Silurian graptolites. ‘ ' Acknowledgment is due the trustees of Cornell Uni- versity for financial assistance during the summer of 1940, at which time valuable aid in the field was given by C. M. Nevin of Cornell and by L. E. Nugent, for- merly of the same institution. Among others who have given freely of valuable; counsel on the problems of the Great Basin during this work are H. G. Ferguson, the late Edwin Kirk, C. A. Anderson, R. J. Roberts, and James Gilluly of the US. Geological Survey. A. R. Palmer and R. J. Ross, Jr. aided in determination of the Cambrian-Ordovician boundary. Finally, the writer expresses thanks to the late Mr. William Martin and Mrs. Martin of the Mar- tin Ranch for many courtesies extended during the fieldwork. GEOLOGIC STRUCTURE AS RELATED TO STRATIGRAPHY The Paleozoic column in the Antelope Valley-Eureka region is about 25,000 feet thick, largely marine, and reflects the structural and stratigraphic setting of a classic geosyncline. A long-continued depositional his- tory, well supported by the data of paleontology, paral- lels the established record in other and more fully studied major belts of geosynclinal accumulation. Within the long interval from Late Cambrian to Mis- sissippian the Antelope Valley strata reveal no clear structural evidence of strong compressional deforma-' GEOLOGIC STRUCTURE AS RELATED TO STRATIGRAPHY 7 tion. Broad regional uplift unaccompanied by ap- preciable warping of strata took place in the Ordovician near the end of Pogonip time and probably during de- position of the Eureka quartzite. Uplift and emer— gence are documented by local disconformity near the close of the Silurian. The Mississippian rocks mani- fest revolutionary tectonic and geographic changes with introduction of impure sandy and pebbly limestone, carbonaceous shale, coarse siliceous sandstone, and con- glomerate. These Carboniferous siliceous clastics, though largely marine, contain remains of land plant-s indicative of nearby coal-swamp environments. The present study does not shed light directly upon the problem of intense late Paleozoic crustal movement in the central and western Great Basin (Roberts and others, 1958). Date of the major Roberts Mountains thrusting remains uncertain in this area, where the Mississippian rocks of the Chainman shale and Dia- mond Peak formation are the youngest demonstrated by mapping, to have actually been overridden by Or- dovician grap’oolitic deposits of the Vinini formation. However, the Permian beds of the Garden Valley forma- tion and overlying sandstone beds assigned to the Cre- taceous Newark Canyon formation are strongly de- formed. Permian beds resting on the overthrust Vinini (100. 82) may actually have been involved in the thrust- ing; if such eventually proves to be true the earliest thrusting in. the Antelope Valley area came about after Wolfcamp (Early Permian) time. Antelope Valley is probably situated near the west margin of the Great Basin prism of Paleozoic marine rocks in which the stratigraphic column and paleonto- logic record of this era are most nearly complete. Maximum stratigraphic continuity or completeness in the time and paleontologic sense does not necessarily denote maximum thickness of the column. Such a con- clusion would perhaps be illogical because of phenom- enal thicknesses known to have piled up locally in subsidiary basins during less than a single geologic period. How far west of Antelope Valley this more continu- ous Paleozoic column extends in these latitudes cannot at present be determined. Westward, north of parallel 39 (fig. 2), through the Monitor, Toquima, and Toiyabe Ranges field evidence suggests attenuation of the col- umn, accompanied by), significant facies change and wedging out of stratal units within the stratigraphic interval ranging from late Middle Ordovician through Carboniferous time. Beyond the Toquima Range, ex— posures of unaltered Paleozoic strata are unfortunately few, because of plutonic intrusion and cover of later rocks, especially Cenozoic volcanic rocks. Yet farther west, through The Sierra Nevada belt in this latitude, intrusion, metamorphism, and burial by later rocks pre- vent elucidation of Paleozoic history, except in the broadest and most sketchy of inferential terms. Lithologic facies changes from east to west, so well illustrated by Ordovician and Devonian rocks of this region, no doubt have paleotectonic significance. These changes may be related in part to rise and fall of a major geanticline to the west, as postulated by Nolan (1928). Manifestations of intense post—Paleozoic deformation are widespread at Antelope Valley. The Paleozoic strata, including those of Permian age, are folded and thrust, and all rocks of the region have been cut by innumerable normal faults. Certain homoclinally tilted blocks of Paleozoic strata appear at least to rep- resent normally faulted segments of north-south trend- ing and rather open folds. Such are the eastward— dipping Ordovician section at Ninemile Canyon and the westward-dipping block that forms Martin Ridge. Rocks of the Pogonip group along the Antelope Range front west of Ninemile Canyon exhibit reversal of dip from east to west. There is evidence here of reverse faulting near the axis of this supposedly anticlinal flexure (fig. 3). Simple, relatively uncomplicated symmetrical folds are not the rule in the central Great Basin. In Ante- lope Valley, the Dry Lake anticlinal arch and a similar structure at Bellevue Peak most nearly approach this ideal form. As seen in the Mahogany Hills (pl. 1), the Dry Lake arch appears as a broad open anticline, for the greater part in low-dipping Devils Gate limestone underlain by Nevada formation. Between Dry Lake and Hay Ranch this almost domelike structure has distinct topo- graphic expression, and the Devonian beds of the Devils Gate are traceable from east to west across the axial zone. Dip of the west limb is on the whole rather gentle toward Antelope Valley; here and there, the slope of the west limb is almost coincident with the dip. There are, however, many irregularities and local steepenings of dip due to faulting. " The comparable flexure at Bellevue Peak, where the Pogonip group and Eureka quartzite are involved, may in fact be merely a southward prolongation in lower strata of the Dry Lake arch. Position of Ordovician strata in Martin Ridge and the opposing Antelope Range on the east suggest that southernmost Antelope Valley may be virtually synclinal (pl. 2). The origin of broad folds like the Dry Lake arch is probably related to compressional stresses, which are also responsible for thrusting. Ordovician beds of the Vinini on the east ‘limb at Yahoo Canyon and Devils Gate with little doubt overrode the arch that PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA .353» no 5382 no“ u 35a 8w 6:33:53 nafigocuo M332? .owncfi onefiwuad .nehndo 38052 no 5:3 ~MIM on: was: :058m‘.m EEG—rm hm... 8.8 own. 0&0. comm Jooww M. \ ooop 1.83 / / .oomn Ibo? 832:2 .88 I.ooom *( I . . .003 n w r i. I)#\. W foomm SIN? 3 Jm J} 3 \ m UV. m w. wcoymmfz E2680 m u. .u, a w W m, ” a 888E: w b u >c=m> mao_2c< W 5:952 $80 :8ch so an. m, w. wczmm: 869 2.529 >5:ka w m M. H. a o U PALEONTOLOGIC STUDIES 9 could have formed in the lower plate mntemporaneous— 1y with the thrust movement. Thrust faults, most important manifestations of com- pressional deformation in this area, range in magni- tude from relatively minor ones that displace rocks normally present in the local stratigraphic section to at least one of far greater magnitude that introduced foreign sedimentary facies not present in the normal Antelope Valley column. It is probable that most. of the minor thrusts were contemporaneous in origin and sympathetic with the major thrust movements. In the category of minor thrusts is a low—angle thrust well shown on the west side of Copenhagen Can- yon (pl. 2; fig. 4), where massive cliff-forming An- telope Valley limestone rode over less competent Lower Devonian beds of the Rabbit Hill limestone. Drag folds suggest west to east movement of the upper plate. At locality 3 in Whiterock Canyon a thrust outlier of Pogonip rests upon Lower Devonian Rabbit Hill, east of the principal thrust contact. Comparable thrusting is evident on the east side of Antelope Val— ley; for example, in the northern Antelope Range the Cambrian Windfall formation and overlying Pogonip override the Nevada formation. Between ~Charnac Basin and Devils Gate pass, a linear distance northeastward of 35 miles, there is abundant evidence of major thrust displacement. Be- yond doubt these displacements are related to the wide- spread Roberts Mountains thrust (Merriam and Anderson, 1942, p. 1701). In most places the upper plate consists of Ordovician Vinini formation, which occurs in thrust relationship to other rocks at all known exposures. Garden Valley Permian strata may also have formed part of the upper thrust plate; this Per- mian unit rests unconformably upon the Vinini at Tyrone Gap and probably also in the Twin Spring Hills. On the west side of Charnac Basin, at Whiterock Canyon narrows (10c. 13) and in the Twin Spring Hills, graptolitic shales and cherts of the Vinini override the Pogonip; near Devils Gate pass and in the Mahog— any Hills the Vinini is thrust over Middle and Upper Devonian Devils Gate limestone and Mississippian rocks of the Chainman-Diamond Peak sequence. De- tails of these outliers and their stratigraphic relations are discussed below under description of western grapto- litic facies. , The Vinini formation with its graptolitic facies was probably deposited in a western subprovince of the Great Basin Wholly distinct from that in which the normal or eastern carbonate Ordovician was laid down. The writer’s present paleogeographic and paleotectonic conception calls for great shortening of the Earth’s crust west of the Antelope Valley belt. West to east movement of the upper plate is clearly to be measured in tens of miles, probably no less than 35 miles and possibly at least twice this figure. Scattered masses of resistant silicified breccia with flat distribution mark the sole of the Roberts Mountains thrust at places where the upper plate has been almost entirely removed by erosion. Breccia masses of this kind are associated with the thrust west of Charnac Basin and in the Twin Spring Hills at the north tip of the Monitor Range. Large outcrops of unsilicified limestone breccia lie on the east side of Antelope Val- ley, 4 miles south of Lone Mountain (pl. 1., 10c. 88). Flat distribution suggests that it also may be a product of thrusting. However, these isolated limestone brec« cias pertain to the Devils Gate limestone and, in part at least, represent the noncataclastic depositional lime- stone mud breccias so characteristic of that formation in the Mahogany Hills area. Of innumerable high-angle and normal faults in this area, only those producing the most obvious strati- graphic displacements are shown on the accompanying reconnaissance maps (pls. 1, 2). Among these faults is the northwestward-striking Ninemile Canyon fault along which Goodwin limestone together with over- lying Ninemile formation abuts against the Upper Cambrian Windfall. In addition to range-front faults, like those along the western Antelope Range, several interior faults and fault zones have influenced geomorphic sculpture ap- preciably. Examples are the Ninemile Canyon fault zone and the Copenhagen Canyon fault zone. A geo- morphically similar zone of late faulting probably fol- lows Yahoo Canyon southward through Dry Lake. PALEONTOLOGIC STUDIES Nowhere in western North America is a record of Paleozoic marine life more amply preserved than in the region bounded on the north by the Roberts Mountains, on the west by the northern Monitor Range, and on the east by the Diamond Mountains (fig. 2). Within this broad region the Eureka district is known above all for its Cambrian and upper Paleozoic faunas and the Roberts Mountains especially for Silurian and Lower through Middle Devonian. Antelope Valley excells in the richness \‘of its Ordovician and Devonian faunas, ranging in both systems from very early to late stages. The stratigraphic paleontology of the Cambrian and upper Paleozoic are briefly touched upon in this report, as it has recently been dealt with in connection with the work at Eureka (Nolan, Merriam, and Williams, 1956, p. 5—23; 54—68)." Large fossil collections were PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA 10 Emu «EAS— gwnogan .533 .52. 55.5 5:6qu 05 .3 3—02 no 5.3.5353 cash: “532i .093.“ now—:02” £9555, Honda—.5095 «a .VIV 0:: mac? flofiowmld among .5393 «o 5382 «on a 82: com 6532:: hum“. ooow 009 o 89 888E: >m=m> oao_3:< uoneuuo; uaSequadoo anzuenb enema coszLE x85 :8ch c3952 2:95.05. mtmoom 328$: ___I gonna 838E: >m=m> 823c< boom .OOmo boon bom n boom .oomw PALEONTOLOGIC STUDIES 1 1 made from five Ordovician formations. A preliminary study of these fossils has been made to establish strati- graphic demarcation. Least fossiliferous are the Si- lurian rocks of Antelope Valley, which are in large part dolomite. Recently, however, small lenses of dark car- bonaceous Silurian dolomite were found to contain excellent silicified material, which thus opens a new approach to study of these strata. Walcott (1884, p. 4; p. 270—273; p. 284—285) called ‘ attention to the richly fossiliferous Ordovician strata (“Lower Silurian” of 1884) of this region, and as an outcome of his collecting near Wood Cone (pl. 1), ap- pears to have been the first to record the presence of Late Ordovician (Richmond) fossils in the Far West. Beginning in 1928, with a visit by Edwin Kirk (1933; 1934), several Ordovician collections were made in the northern Antelope and Monitor Ranges by US. Geo- logical Survey and Smithsonian Institution parties. Brachiopod materials collected by Edwin Kirk, G. Arthur Cooper of the Smithsonian, and the late Josiah Bridge of the US. Geological Survey, together with those obtained by the writer, have in part been treated by Cooper (1956) in a memoir on Chazyan and related brachiopods. An earlier contribution on Ordovician brachiopods by Ulrich and Cooper (1938) describes several species obtained from Pogonip rocks of Ante- lope Valley. Whittington (1948, p. 567) began de- tailed work on Antelope Valley Ordovician trilobites with a special study of the diagnostic Ninemile form Kirkella vigilans. A study by Kirk (1930) of the re- markable gastropod genus Pallisem'a from the Monitor Range and other Great Basin localities established the stratigraphic range of an important Ordovician indi- cator of the Cordilleran belt. The practical objective of this report is to record the stratigraphic occurrence of common fossils that aid in establishing vertical order in the Ordovician column and in correlating with other western sections. liminary review of the Ordovician faunas shows that most of the systematicand descriptive work lies ahead. Distinctive forms in nearly all the Ordovician zones described bear morphologic resemblance to species de- scribed from eastern North America and more remote regions, thus providing a basis for provisional long- range geologic correlations. During this investigation a great part of the paleon- tologic study was concentrated on three of the four Devonian formations, as part of a general program in progress since 1933. During this period an attempt Pre-- has been made to establish workable fauna]. zones in the Roberts Mountains area, at Lone Mountain, and in the Eureka district (Merriam, 1940; Nolan, Merriam, and Williams, 1956) . Systematic studies of special biologic groups have been undertaken, especially the brachio- pods and rugose corals. Effort has been made to obtain stratigraphically zoned coral collections, relating the biologic changes to factors of ecology and sedimenta- tion. Taxonomy of many of these Devonian corals has been treated in valuable contributions by Erwin C. Stumm (1937; 1938; 1940). Brachiopods have proved thus far to be the most use- ful fossils for stratigraphic zonation and correlation of Devonian strata in this region. Dependable key forms of very wide geographic distribution are Stm'ngo- cephalus, Bemselandz’a, the Leptoooelia group, and spirifers of the arenosa group. Of the many distinctive Devonian brachiopod species collected in the central Great Basin, only a small minority have been described or studied. Other Devonian invertebrate groups present in abundance, 'but almost unstudied by specialists, are the stromatoporoids, Bryozoa‘, and Ostracoda. Conodonts, common in the lower port of the Pilot shale, are present also in lower horizons of the Devonian column. Except for routine determinations, these remain almost un- studied. In conjunction With the Antelope Valley strati- graphic work, a monographic study of Lower Devonian faunas was undertaken, with special emphasis on the Rabbit Hill limestone of Helderberg age and Oriskany faunas of the lowermost Nevada. Initial objective of this project was to determine the stratigraphic posi- tion of the Rabbit Hill relative to the Nevada, for the two were not found in the same section. Among unresolved paleontologic questions disclosed by this investigation are those of paleoecology. Fore- most is that of the true significance of graptolite shale facies and the nature of physical and bio-environmental factors controlling loci of black shale deposition, while seemingly contemporaneous carbonate sediments with contrasting shelly faunas accumulate elsewhere. These, problems are uppermost when attempts are made to equate the Ordovician Vinini formation with units of the Pogonip group, and are met again in connection with stratigraphy and correlation of the Copenhagen formation, the Hanson Creek formation, and the Rob- erts Mountains formation. 12 The richly fossiliferous Nevada formation and the Devils Gate limestone are likewise promising fields for biofacies and population study. As noted elsewhere the environments of sedimentation and faunas of the lower part of the Nevada change almost completely be— tween the Diamond Mountains on the east and the Lone Mountain-Antelope Valley belt to the west. Restricted or local environments of profuse coral growth in both the Nevada formation and the Devils Gate limestone lend themselves to eventual biofacies research. Finally, the conodont facies of the Pilot shale indicate a special environment worthy of investigation. Correlation of the Devonian rocks at Antelope Valley with other sections in the Great Basin and in the-Far West has been facilitated by large collections made in other areas by the writer for purposes of comparison. Exclusive of many sections in central Nevada, these areas include the southern Shell Creek Range in Ne- vada, the Inyo Mountains in California, and the Kla- math Mountains region of northern California. Fossils collected during the field seasons of 1940 and 1941 form the principal basis for provisional faunal lists here included. These collections, originally at Cornell University, have been transferred to the US. National Museum through the courtesy of W. Storrs Cole. Additional collecting in 1948, 1950, and 1954 provided material now deposited in the Menlo Park laboratory of the US. Geological Survey. THE PALEOZOIC COLUMN AT ANTELOPE VALLEY Seventeen formations compose the Paleozoic column at Antelope Valley. Fourteen of them are normally superposed (table 1) and constitute what is here re- ferred to as the normal stratigraphic section. Of the three remaining, the Vinini formation of Ordovician age occurs only in thrust outliers, the Lower Devonian Rabbit Hill formation is a western unit thus far recognized with certainty only in the Monitor Range, and the Permian Garden Valley formation makes up isolated exposures in the Twin Spring Hills and at Lone Mountain and isseemingly associated everywhere with overthrust rocks of the Vinini formation. Distribution of the normal section formations with respect to geologic system is as follows: Upper Cam- brian, 1 formation; Ordovician, 6; Silurian, 2; Devo— nian, 2; combined Devonian and Early Mississippian, 1; and Mississippian, 2. Of the systems well exposed PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA in this belt, the Ordovician is the most diverse with respect to rock type and faunal differentiation. Twelve of the normal Antelope Valley Paleozoic formations are present also in the Eureka mining dis- trict, although significant facies differences are intro— duced between the two areas. For example, dolomiti~ zation, which locally affects all parts of the carbonate Silurian section, makes it difficult to differentiate beds of the Roberts Mountains formation from the Lone Mountain dolomite. Such appears to be true at Eureka (Nolan, Merriam, and Williams, 1956, p. 37). Un— recognized in the Eureka area are the Copenhagen formation and the Rabbit Hill limestone (Helderberg). The western facies overthrust beds of the Vinini just reach the edge of the Eureka district near Devils Gate. Four of the units here described are either newly designated or have recently been defined in connection with the Eureka studies (Nolan, Merriam, and Wil- liams, 1956). vThese divisions, each with type section designated in the Antelope Valley area, are the Nine- mile, Antelope Valley, and Copenhagen formations of the Ordovician system, and the Lower Devonian Rabbit Hill limestone. Unrecognized thus far outside of the Antelope Valley area is the Copenhagen formation. The Upper Cambrian Windfall formation and the Lower Ordovician Goodwin limestone were defined in revision of the stratigraphy of Eureka, Nev., where the Goodwin is the lowest unit of the emended Pogonip group. ‘ The Ordovician, 4,300 feet thick, and the Devonian, about 4,200 feet thick, are in the physical and paleonto- logic sense especially full. The Silurian, 2,200 feet thick, about half the thickness of the others, shows far less faunal diversity, partly owing to the fact that most of it is dolomite and contains fewer identifiable fossils. ' Carbonate rocks predominate in the normal strati- graphic column from Upper Cambrian through the Devonian system. The Eureka quartzite is a notable exception; in fact, the vertical change from limestone of the Pogonip to clean quartz sand is one of the more striking shifts of its kind in Cordilleran Paleozoic his- tory. Following abrupt readjustment to marine'car- bonate conditions at the end of the Eureka cycle there were occasional but relatively rare and localized re- currences of pure quartz sand deposition in the Silurian and Devonian. THE PALEOZOIC COLUMN AT ANTELOPE VALLEY 13 TABLE l.—Normal stratigraphic section at Antelope Valley, Nev. Age Group or formation Thickness (feet) Mississippian Chainman shale and Diamond Peak formation, undifferentiatedl Lower part of the Pilot shale 2 75+ Upper —————— Devils Gate limestone 3 1’ 200 Devonian Middle Nevada formation 2 2’ 500 Lower Disconformity 3 Lone Mountain dolomite 2 1, 570+ Silurian Roberts Mountains formation 600+ Hanson Creek formation 350 Upper —————— Eureka quartzite 150+ Copenhagen formation 350 Middle Ordovician —— — —?— — — Antelope Valley limestone 1, 100 Pogonip group Ninemile formation 550 LOWer Goodwin limestone 1,800 Cambrian Upper Windfall formation 300+ 1Upper part of the Pilot shale and Joana limestone unrecognized. * Unrecognized on west side of Antelope Valley. ' Rabbit Hill limestone (Helderberg) unrecognized in normal stratigraphic section; present only on west side of Antelope Valley. The Mississippian period brought a return to wide— spread and persistent deposition of silicious elastic sediments on a scale comparable to that -of the Early Cambrian. In the central Great Basin these condi- tions persisted with only occasional deposition of im- pure sandy-silty carbonate into Permian time. As our geologic understanding of this region in- creases With mapping progress, problems of sedi- mentary facies come increasingly to the fore. Our Antelope Valley studies, in conjunction with simul- taneous work in the Eureka vicinity, elucidate certain of these lateral environmental changes, particularly in the Pogonip group, the Eureka quartzite, and the Nevada formation. For example, the interval occu- pied by most of the Eureka quartzite to the north and east is filled in Antelope Valley by partly calcareous beds. Again, highly fossiliferous lower shale and im- pure limestone beds of the Nevada in the. Ante— lope Valley belt are replaced east of Eureka by nearly barren dolomite and quartz sand deposits, to which local member names have been given. 665243 0-63—2 Germane to the facies problem is that of primary dolomitization. Areal and vertical changes from lime- stone to dolomite, or the reverse, enter into questions of stratigraphic differentiation and nomenclature in the Ordovician, Silurian, and Devonian, .wherein car- bonates predominate. For example, the Hanson Creek, typically a limestone, passes into dolomite eastward from Wood Cone toward the Eureka area. Similarly the Silurian Roberts Mountains formation, prevailingly limestone to north and west, becomes dolomite at Lone Mountain and eastward in the Eureka vicinity. Geo- graphically shifting loci of dolomitic replacement in the Nevada and Devils Gate Devonian are treated else- where. Also oonsidered below is the problem of pos— sible westerly facies change from uppermost Lone Mountain dolomite into Rabbit Hill limestone. System limits, subjective and discretionary at best, remain provisional in this belt of continuous geo- synclinal accumulation. The Antelope Valley Pale- ozoic column clearly shows the period-to-period biologic 14 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA changes, which are the traditional basis for rock system delimitation; the harmonizing of biologic changes and ranges with discrete rock boundaries, as conceived for the ideal world rock system, is less obvious in some places. Searching analysis and comparison of border- line faunas from this region with those of eastern America and the Old World are needed. Some border strata are subject to adjustment or possible system re- assignment. An example is the borderline Uaryocam's shale, placed tentatively in the Ordovician system on a paleontologic basis, but possibly in the physical sense a facies of a unit elsewhere classed as Late Cambrian. Assignment of the Hanson Creek formation and its Richmond faunas to Late OrdoviCian rather than Early Silurian awakens an unresolved boundary question. The Silurian-Devonian boundary is likewise not well fixed at the Lone Mountain-Nevada contact, and may eventually be found to fall within the uppermost Lone Mountain dolomite. As viewed at present, the Devo- nian—Carboniferous boundary 'at Antelope Valley is / more than ordinarily subjective and is based on ques- tionable paleontologic criteria. It now falls at some indefinite horizon within the Pilot shale, where de- lineation would appear to depend on future studies of Pilot conodont assemblages. CAMBRIAN SYSTEM GENERAL FEATURES The Cambrian system is poorly exposed at Antelope Valley. Only in the northern Antelope Range has erosional downcutting penetrated deep enough to reach the top of the system. Older Cambrian rocks are un- doubtedly present in depth, for 25 miles northeastward at Eureka 8 formations, ranging from Early to Late Cambrian, constitute one of the more complete records of this system in western North America. That so full a column ends near Eureka is scarcely conceivable, yet to the west in these latitudes few outcrops of Cambrian strata have been identified. Westward continuity of the system in depth is suggested by Lower Cambrian rocks of the Toiyabe Range west of Round Mountain (fig. 2) as reported by Ferguson (1954) and in the Osgood Mountains and Hot Springs Range as reported by Roberts and others (1958). Upper Cambrian beds of the Windfall formation are exposed on the east side of Ninemile Canyon, where they occupy a narrow strip bounded on the west by the Ninemile Canyon fault, and pass eastward downdip beneath Lo'wer Ordovician Goodwin limestone (pl. 2; fig. 5). Sheared strata, which remain unidentified within the Ninemile Canyon fault zone, may well in- clude Dunderberg shale, normally to be expected below Windfall. A WINDFALL FORMATION GENERAL FEATURES Type section of the Windfall formation is in Wind- fall Canyon, Eureka mining district, where it comprises 650 feet of limestone, shale, and chert resting conform- ably on Dunderberg shale; it is succeeded without dis- cordance by the Goodwin limestone (Nolan, Merriam, and Williams, 1956). The type Windfall includes two units, the Catlin member below and the Bullwhacker above. Hague’s (1883; 1892) “Pogonip limestone" embraced these Upper Cambrian strata, excluded by us from the revised Pogonip group. Beds in Antelope Valley assigned to the Windfall formation are similar lithologically to the Catlin member at Eureka (figs. 5 and 6). The Bullwhacker member has not been recog- rniz'ed. Instead, strata similar lithologically to the Catlin are overlain by a shale unit not recognized in the Eureka area. LITHOLOGY AND STRATIGRAPHY The Windfall formation as exposed in Ninemile Canyon consists largely of medium to fine-grained platy impure sandy and silty limestone beds of medium to dark-gray. Dark-gray to black chert occurs in fairly even interbeds several inches thick. An 8-foot chert zone, 90 feet below the top of the formation, includes a small amount of limestone. Especially distinctive of the formation at Ninemile Canyon, but of the lower or Catlin member only at Eureka, are laminated chert layers which reveal a rhythmic alternation of light and dark-gray millimeter-thick laminae. Laminated chert layers are most numerous in the upper part of the Wind- fall at Ninemile Canyon. In the type Windfall section at Eureka chert layers appear to be limited to the lower . half of the lower or Catlin member. 4 Heavy-bedded highly fossiliferous rather coarse- grained limestone units that are prominent in the Cat- lin member at Eureka were not recognized in the section at Ninemile Canyon. One of these is the basal massive light-gray limestone of the Catlin bearing a fauna re- 15 CAMBRIAN SYSTEM .nozoom no :0333 you N 3:3 com .nnon—dfiuom ago—.520 and 923560 “RED M2323 .cuadfi 333:4 snob—do ciao—:2 ad .OID 0:: Mac? :ofluomld 553p.— _|lll]|]|.|_ men— 000 0 00m 035 935—250 3.5.05 2:: .5232... «van 3:2 3 ood I. i WI/I/I/Illlllf/I/Alns/wm/A/é .. . . . ‘ ./ in ”/Ufl/fl/Wflflm/flflllflfll/N” HUI” .””7/” ,I//.// / .‘ . . . ‘W/Z .83 / / r / f n ,7/ ' v /I”7Mfl/”/W”””/ll/I/Il””/II . . J /I//fl””//////////II”I //// I u. . 2:3 /////////I///// WM , H! “:1 , . 5:50 _ x. ///////////////I ‘ ‘ 1,: p . y o _ _ 52.: z . //fl”fl”fl/////IU/IU/I. /fl”/////I/v"~ // i _ 33:qu _ I .myf/J yflZ: / ‘ :1 I a utuSek é/Q/i/fl/fi/l/fly/Jflk/n. I /~//:/./ 1 x 523...: w _,,,/, (/V/WZnfl‘ylffl/fflJV/fl7/f. , . . 23m: x T «x , ,/, [I 71777!” Nil/[7:51], I“, x ' :7/wfl//.,//// 757:1,” Ip/i/JIWIIIJVI/lfifiwV/fl v V, II 7 uouano; auwaum 32. 2:50.00 .0000 M: 0mm I 009 , +C 00¢ cozoELo. o:Emc_z wcofiwczv Ezuooo :chEkz :Eucts :7 W/ V .88 W In. mm %d no? 0A mm. m K b x 16 ,, PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA lated closely to that of the underlying Dunderberg shale. Only about 300 feet of Windfall was measured in the Ninemile Canyon section, because the lower parts of these strata are deformed. Dislocated beds east of the Ninemile Canyon fault (fig. 5) may include over 250 feet of the lower part of the Windfall and possibly, Dunderberg shale. AGE AND CORRELATION Identification of these beds as Windfall formation is based largely on the distinctive laminated chert. Fossil collections made by A. R. Palmer (written communi- cation, 1959) from the lower silty limestone layers at Ninemile Canyon contain Bienvillz'a cf. B. comm Bill- ings, Plicatoh'na sp., and Lotagnostus trisectus (Sal- ter). Bienvillz'a and Lotagnostus, although represented by different species, are common in the middle part of the Catlin member of the Windfall formation near Eureka (Nolan, Merriam and >Williams, 1956, p. 22). Studies of type Windfall fossils by G. Arthur Cooper of the US. National Museum and by A. R. Palmer of the US. Geological Survey 3(Nolan, Merriam, and Wil- liams, 1956; Palmer, 1955) make possible a three-fold zonation. Two of the zones are in the lower or Catlin member, the third corresponds to the Bullwhacker member. According to Palmer massive limestones of the lowermost Catlin contain Pseudagnostus prolongus (Hall and Whitfield) together with species of E lvimla and Imingella, a fauna differing but slightly from that of the underlying Dunderberg. Remainder of the Cat- lin bears a fauna with Bienvillia coma: (Billings), Tostom'a iole (Walcott) , and species of E urekia, Lotag- nostus, Gemgnostus, and Pseudagnostus. Palmer regards the upper Catlin fauna as late Late Cambrian (T rempeleau) ; while the Bullwhacker, with Elicia mum (Walcott) and lz'urekia granulosa Wal- cott, is considered by him to correlate with slightly younger horizons of the Trempeleau. Catlin brachiopods determined by Cooper include species of Lingulella and Finkelnburgz'a. In the Bull- whacker he has recognized Homotreta eurek‘emis Ul- rich and Cooper, E [karma hamburgensis (Walcott), Westo'm’a iphia (Walcott), Conodisous bu-r'lingi (Ko- bayashi) , and X enorthis n. sp. The shale unit termed “Oaryocm-is shale”, which overlies the Windfall formation in Ninemile Canyon, seems to occupy the interval of the upper part of the Windfall or Bullwhacker member in the Eureka district (fig. 6). Conceivably the shale may be either a Late Cambrian shale facies of Bullwhacker age, or alter- natively, younger than Bullwhacker and therefore early Ordovician rather than Late Cambrian. Pale- ontologic evidence would favor Ordovician assignment, for Caryocam's is seemingly unknown in rocks of Cam- brian age. No graptolites have been found in this black shale. ORDOVICIAN SYSTEM GENERAL FEATURES The Ordovician system is especially well represented at Antelope Valley. Six formations, or about 4,300 feet of prevailingly carbonate sediments make up the normal section, and range from Early Ordovician to Late Ordovician (Richmond) age. Graptolite-bearing sediments not present in the normal carbonate sequence, comprise an additional major division known as the Vinini formation. The normal Ordovician sequence is as follows: Fed Hanson Creek formation__ Late Ordovician __________ 350 Eureka quartzite ________ Middle and Late Ordovi— 150 cian. Copenhagen formation-“ Middle Ordovician ________ 350 Pogonip group: Antelope Valley lime- Early and Middle Ordovi- 1, 100 stone. cian. Ninemile formatiom _ Early Ordovician _________ 550 Goodwin limestone___ _____ do _________________ l, 800 4, 300 At Antelope Valley no significant vertical discontinu— ities have been detected in this column. Elsewhere in the central Great Basin there is evidence of possible hiatus at the t0p of the Eureka, and particularly to the north, where the Eureka is separated by disconformity from underlying rocks of varying age. ORDOVICIAN SYSTEM BOUNDARIES Depositional history of the region reveals no evidence that either Cambrian or Ordovician were interrupted by diastrophic events. Failure to recognize physical boundary features and virtual continuity of marine de- position from one period to the other places the burden of system delimitation upon paleontological judgment. As here adopted the subjective system boundaries based on paleontologic evidence may sometimes require arbi- trary adjustment to local requirements of geologic map- ping on a strictly lithologic basis. In actual mapping, a system boundary determined by ranges of fossils is likely to fall somewhere within a formation, or lesser unit, rather than at its exact top or bottom. In the Eureka district (Nolan, Merriam, and Wil- liams, 1956, p. 23—25, 26—27) the lower limit of the Ordo- vician system may be interpreted paleontologically as falling somewhat above the base of the Goodwin lime- stone, for fossil holdovers of established Cambrian af- finity cross the lithologic contact into the basal 20 feet or so of that formation. Above the lowermost Goodwill 0RDOVICIAN SYSTEM , l7 fossil zone there is no recurrence of fossils of Late Cam— brian age and the acknowledged Ordovician Kai‘nella— Nano’rthis fauna is present. In mapping, the baSe of the Goodwin limestone is considered as base of the Ordovician system in spite of Cambrian holdovers. In Antelope Valley, where the boundary rocks differ from those at Eureka, the Cambrian-Ordovician line is placed between the Windfall formation and the over- - lying dark-gray shale with Garyocaris, a unit not found in the Eureka area (fig. 6). Though provisionally classed as Ordovician and included with the Goodwin, the systemic position of these dark shale beds is incon- clusive. The small phyllocarid crustacean'Uaryocarz's, which these shales contain, is unknown in rocks of Cam- brian age, but occurs generally in association with the Vinini Ordovician graptolite faunules. The Ordovician—Silurian boundary is likewise drawn mainly on faunal criteria, the appearance of M onogmp- tus and pentamerid brachiopods. Although not every— where recognizable in the Great Basin, a-highly distinc- tive cherty limestone commonly marks the basal Silurian in the area under consideration. FACIES PROBLEMS Study of Antelope Valley Ordovician rocks in com- parison with those of adjoining areas brings sharply in focus the complexities of lateral facies change. As areal mapping becomes more refined and brings fuller appreciation of the intricate relations of deposition there is a corresponding need for realistic nomenclature to express these complexities. The scheme of stratia graphic classification inevitably becomes more involved. Between Eureka and Antelope Valley, a distance of about 12 miles, significant lateral changes are evident in most of the Ordovician units. Facies changes became evident in the boundary rocks when an attempt was made to relate the Cambrian-Ordovician boundary at Eureka with that in Antelope Valley (fig. 6). With reference to the Eureka quartzite-Copenhagen interval, the lithologic changes are especially remarkable as these rocks are followed westward. Lithologic boundaries shift vertically up or down relative to imaginary time- stratigraphic datum planes postulated on a paleonto- logic basis. Normal marine carbonate facies predominate in the Antelope Valley Ordovician rocks. With these may be contrasted the little-understood marine depositional en- vironments represented in graptolitic shale outliers. A third distinctive facies is the vitreous Eureka quartzite. These unfossiliferous partly crossbedded sands may represent very shallow marine or marginal beach—dune accumulation, but the possibility of continental depos— itation is also not unreasonable. A provocative facies problem of this region involves the Vinini formation of Early and Middle Ordovician age in relation to the normal carbonate sequence. The Vinini strata comprise graptolitic shale, chert, arena- ceous deposits, limestone, and basic volcanic rocks that occur as thrust outliers. Depositional interrelations of the Vinini and the normal carbonate facies remain to be worked out. On the basis of paleogeography the Vinini facies probably represent a western Great Basin marine subprovince, whereas the normal carbonate facies are probably characteristic of an eastern subprovince. Great geographic extent is noteworthy in connection with certain Ordovician rock units of the Antelope Val- ley area. This applies to the remarkable Eureka quartzite and especially to the overlying carbonate for- mation of Late Ordovician age, traceable throughout most of the Cordilleran belt. Strata of the Pogonip time interval, though widely recognized in the Great Basin outside of the central Nevada region, vary.litho- logically from place to place to such extent that we hes- itate to apply the central Nevada or type area forma- tion names. On the other hand most of the major Pogonip faunal zones recognized at Antelope Valley and Eureka are traceable throughout the extent of these rocks in the Great Basin and adjacent regions (fig. 6). Several of these faunal zones have in fact been correlated rather closely with stages in eastern North America. POGONIP GROUP The Pogonip group, which is mainly limestone at Antelope Valley, comprises some 3,450 feet of strata classified in three formations as follows: Thickness (feet) Antelope Valley limestone _____________________________ 1,100 Ninemile formation _____________________________________ 550 Goodwin limestone _________ ‘ ___________________________ 1,800 3,450 Pogonip group as adopted conforms to a redefinition at nearby Eureka, Nev. (Nolan, Merriam, and Williams, 1956, p. 23—29), which includes only those Ordovician rocks between the top of the Late Cambrian Windfall and the base of the Eureka quartzite. Clarence King (1878, p. 187—189) introduced the name “Pogonip limestone” for an estimated 4,000 feet of strata at the north end of Pogonip Mountain, White Pine mining district. These strata overlie quartzites correlated by King with what is today known as Pros- pect Mountain quartzite at Eureka, Nev. King was unable to assign a specific upper limit to the type Pogo- nip, because of alluvial cover. He therefore alluded in the initial description to the Eureka, Nev., section (King, 1878, p. 189), where the base of a conspicuous PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA 18 55D 5 mac—tan con—homo". no 325 3 :52 33:5» 323.: 6:: 5:55 «o 3.2: aqua—>230 uc Eda-3352 was 2532.— uEBonm Baguio nozflotonvlé Hana—rm E o \ u- m \ 9 s \ m aguz W EIE§§§ m, Saig$ u Egg (u 09L!) uouewm KID ueples (u 999) NORM”) need uems 8:3 .30": :3: 65:30: coflmfflo :55an .595 A+ : DOB :o_«wEho~\=£Uc_3 \Illlllll \ \ :o:2moE= 3:01: \ \ ..o:3moE__ 2GEE"... :ocsmoE: :25“? 23m Pvfiouczo E 88 5:25. A: 88 .3505. :58 c. 8: .362. 5:92:53 .2335: pg? \tll \ \ :22; 59.2: 233:0 9.95m. 563280 San: A32 .ouciv £3: .82 x3. \ 1‘ N \ 9 on: 323 E§E§ < .8512 =33; 035 «030/ / m / N a. cot m 32:22 2.2 S~§§M u , as» 0 375.3% 295 «D «9% 0c9 sari: 9 00 H 323:... E; _ l 0: 32. c? m $5333 3 ._ . Eco $.32: 2 ._ . 88 n. 5:33: SEE A: ommv Q .3502 SSH—waist To §=§§w \\ n§~§£ \ \\ \\\ «é £33: \ \ \ I 3:83.: \ \ \ _ $3836~ At ommv £03953 v__Ea:_Z 0:2 ~53me \\ \ a t 33 M \\ 28 53355 4 wucull >3: .225:— .E 35.93%! A: 00,“ 3 9.0505: >v=m> 8225 SS EEK REYEV . a 2533. 8.9.5 OPEN «‘5‘qu \N \ \ \\\l\\ll\|l 13.5.2 \\ h m .3522 \ 9 ommv 5:252 comm—E88 \ \ A: 0m: 2553. 9.25 0 .SEoS \ gm: muguz >\§_m> 823,2 .5»ch =m=uE>> auw>wz 5:55 9.25 , ORDOVICIAN SYSTEM upper quartzite, termed by him “Ogden quartzite,” formed a natural top. In the Eureka district, the “Ogden quartzite” of King is the Eureka quartzite of present-day usage. At other localities, such as the Sul- phur Spring Mountains south of Mineral Hill (King, 1878, p. 191, 193), the “Ogden quartzite” mentioned by King is probably in part the Devonian Oxyoke Can— yon sandstone member of the Nevada formation (Nolan, Merriam, and Williams, 1956, p. 43). Occurrence of Devonian fossils at that locality may have led King to a general Devonian age assignment for those rocks in central Nevada classed by him as “Ogden quartzite" (King, 1878, p. 195). King believed the original “Pogonip limestone” to be 4,000 feet thick and divisible into a lower and an upper half; the lower half containing “Primordial,” or Cambrian, fossils seemingly passed below into shale and quartzite. - Near the top of the upper division 2,000. feet thick, these rocks yielded “Quebec” faunas, today regarded as Ordovician. At Pogonip Mountain and at Eureka, the definition of “Pogonip limestone,” as presented by King 1n his Systematic Geology can be interpreted as broadly ap- plicable to all rocks that lie between Prospect Mountain quartzite of Early Cambrian age and the Eureka quartz- ite of Middle to Late Ordovician age. Such broad and inclusive usage has not, however, been generally adopted. Disadvantages of King’s original definition of the Pogonip as well as his untenable use of “Ogden quartz- ite” were evidently understood by Arnold Hague, also of the Fortieth Parallel Survey. Hence, a few years later, describing the rocks of the Eureka district in more detail, Hague introduced appropriate emendations and adjustments, wisely excluding most of the “Primordial” or Cambrian half of the original “Pogonip limestone” as defined by King. Experience has demonstrated that the Cambrian part of King’s type Pogonip would have been ill chosen as a standard Cambrian column for the central Nevada region. Compared with the 6, 000- foot Cambrian sec- tion overlying the basal quartzite at Eureka, the Pogo- nip Mountain Cambrian measured by King would appear greatly thinned, probably by faulting and sub- sequent erosion. Hague (1883, p. 260; 1892, p. 48) thus applied the emended name Pogonip limestone to strata underlain by What is now called Dunderberg shale of Late Cam- brian age (Wheeler and Lemmon, 1939, p. 26) and overlain by the Ordovician Eureka quartzite. The re- definition by Hague at Eureka, Nev., has been the only generally accepted interpretation. 19 Revision of the Eureka district. Ordovician (Nolan, Merriam, and Williams, 1956, p. 23—36) and the co- ordinated Antelope Valley study depart narrowly from the Hague definition, mainly by restricting the name Pogonip to post-Cambrian rocks and by elevating it 10 group rank with three mappable formations. We ave accordingly excluded from Pogonip those Late Cambrian rocks now called Windfall formation, which constituted the lowermost part. of Hague’s Pogonip limestone at Eureka. Many years of accepted usage of Pogonip, as rede- fined by Hague, would favor retention of the name in application to a group. Such a course seems preferable in this case to complete abandonment of the name, or its restriction to one of the three described formations. In Antelope Valley, though not at Eureka, about 350 feet of shale, siltstone, andlimestone, herein named Co- penhagen formation, occupies an interval between Eureka quartzite and the uppermost formation of the Pogonipgroup (figs. 6 and 7). The Copenhagen is excluded from the Pogonip group because of its ab- sence in the Eureka district, Where the standard section of the redefined Pogonip is located. Moreover, the Copenhagen is probably a facies equivalent of the mid- dle and lower parts of the Eureka quartzite. GOODWIN LIMESTONE GENERAL FEATURES As the lowermost formation of the Pogonip group at Eureka, the Goodwin limestone emended lies between the Windfall formation of Late Cambrian age and the Lower Ordovician Ninemile formation. The type sec- tion (Nolan, Merriam, and Williams, 1956, p. 25) is in Goodwin Canyon 11/2 miles southwest of Eureka. Goodwin limestone, redefined as a lithologic division, is less, inclusive than the original Goodwin limestone of Walcott (1923, p. 466—467, 475), which was never actually used as a map unit. As originally proposed, the formation consisted of approximately the lower 1,500 feet of Hague’s Eureka district “Pogonip lime- stone,” or that part which in Walcott’s view represented the vigorously sponsored but never widely acknowl- edged “Ozarkian System.” In conformity with ac- cepted American standards our paleontological studies indicate that Walcott’s Goodwin embraced several hun— dered feet moreof Ordovician than of Upper Cambrian. The Cambrian part consisted mainly of beds that are here called Windfall formation and which are poorly exposed in Goodwin Canyon. On the other hand those Lower Ordovician rocks that comprise emended Good— win are very well shown in that locality. 20 PALEOZOIC ROCKS OF. ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA As emended, the Goodwin limestone is a mappable lithologic unit carrying highly distinctive faunas; these appear to characterize a natural faunal unit of province- wide distribution. Although the Windfall-Goodwin contact is lithologiCally sharp at Eureka, it does not coincide precisely with the paleontologic boundary be- tween Cambrian and Ordovician. As indicated above, a few Late Cambrian fossils linger on into the basal 20 feet of the emended Goodwin. Kainella-bearing Goodwin limestone at Ninemile Canyon is underlain by carbonaceous shales of uncertain age. These boundary beds are provisionally included with the Ordovician as the basal part of the Goodwin. AREAL DISTRIBUTION The largest exposures of Goodwin limestone at Ante— loPe Valley occur in the northern Antelope Range, where these beds underlie a wide belt along the lower western slopes from Ninemile Canyon southward, and occupy much of the higher medial part of the range north and east of Ninemile Canyon (pl. 2). West of Antelope Valley known Goodwin is limited to a small area at the north end of Monitor Range, small exposures at Whiterock Canyon narrows, and an outlying hillock at the extreme northern tip of Martin Ridge (loc. 49). For continuity of section the Goodwin exposures east of Ninemile Canyon are among the best to be found in central Nevada and worthy of more careful study than has thus far been possible. LITHOLOGY AND STRATIGRAPHY Smooth, dark-gray carbonaceous clay shales and-cal- careous shales with Cary/00am compose the lower part of the Goodwin at Ninemile Canyon (fig. 5). On weathering these become light gray, resembling organic upper shales of the Vinini formation, but unlike the upper part of the Vinini are not known to contain chert. These shales are lithologically distinct from cherty shales of the Vinini in the range front outlier 114 miles northwest of the measured section (loc. 67). Fairly pure, fine-grained subporcellaneous limestone predominates in the Goodwin of this area. This lime- stone is commonly of light to medium gray color on fresh fracture, but in some places is cream colored or pinkish. Weathered surfaces are light tan, buff, and limonite brown. The formation is on the whole well bedded; individual layers range from less than half an inch to about 2 feet thick. A few thinly laminated in- terbeds and argillaceous shale partings are light gray or greenish gray. Thin platy weathering is character— istic of the lower half of the formation. Interfaces between limestone layers and shale partings show lumpy and pitted features; at certain horizons worm tracks and castings are abundant. Light-gray to whitish chert lenses and nodules be- come abundant near the middle of the formation. The chert-bearing lime tends to be thicker bedded than the chert-free variety with fewer shale partings. In the lower platy part of the formation, phosphatic and calcareous brachiopods and trildbite shells are common, becoming scarce in the heavier bedded cherty limestone beds above. Although depositional contacts were not observed the Uaryocamls, shale appears to be conformable with beds above and below in a continuous stratigraphic succes- sion. As presently interpreted, the Cambrian-Ordovi- cian boundary is either within or at the base of these shales (fig. 6). Top of the Goodwin is marked in the Antelope Range by an abruptly gradational change to greenish- blue and dark-gray shale and limestone beds of the N inemile formation. Three lithologic subdivisions are distinguishable in ’ the Goodwin limestone of Ninemile Canyon. In as- cending order they are: member A, a basal dark-gray carbonaceous and partly calcareous shale, 150 feet thick, called the Camocam's shale; member B, a middle thinly bedded, platy weathering limestone, 700 feet thick, containing very little chert; and member C, an upper interval, 950 feet thick, in which light-gray and white chert is fairly abundant and the thicker limestone beds form steep-bold outcrops. The middle thinly bedded unit resembles lithologi- cally the Late ‘Cambrian Bullwhacker member of the Windfall formation near Eureka, but it carries the distinctive Early Ordovician Kainella fauna. Scarcity of chert distinguishes these beds from the lower few hundred feet of Goodwin at Eureka Which contain an abundance of light-gray chert. At Ninemile Canyon, cherts of this kind appear only in the upper 950-foot thick—bedded unit. Beds that are about half chert occur 1,000 feet stratigraphically above the Caryocam's shale. Evidently the bottom of the cherty facies trans- gresses time, becoming much younger westward from Eureka towards Antelope Valley (fig. 6). Dolomitization is relatively unimportant. in the Goodwin. Patches occur in a 130-foot interval of the upper cherty subdivision at Ninemile Canyon, begin- ning 450 feet below the top of the formation (fig. 5). In the Eureka area dolomite occurs about 300 feet above the bottom of the Goodwin. THICKNESS The measured Goodwin section at Ninemile Canyon is 1,800 feet thick, or about 800 feet thicker than the measured section at Eureka. Thicknesses of individual subdivisions in the Ninemile Canyon section are as fol- lows: Lower Uaryocam's shale (member A), 150 feet; 0RDOVICIAN SYSTEM , 21 middle thinly bedded limestone unit (member B), 700 feet; and upper cherty limestone unit (member C), 950 feet. No measurement was possible on the west side of Antelope Valley, because of incomplete expo- sure of the Goodwin; AGE AND CORRELATION Only the small phyllocarid crustacean Garza/00am was found in member A, the lower shale unit. Fossils are numerous and diverse in member B but rather uncommon in member C. As crustaceans of the C'aryocam's type are unknown in the Cambrian and especially characteristic of Ordo— vician graptolite shales, the beds in question are pro- visionally classified as Early Ordovician. Previously it was considered likely that the shale beds were a facies of the upper part of the Windfall of Late Cambrian age (Nolan, Merriam, and Williams, 1956, p. 21). Canyo— cam'a is abundant, unaccompanied by other forms. The phyllocarid is referred to Uaryocaris curvilata Gurley, resembling most closely a variety in the graptolite shales of the Hailey guadrangle, Idaho, and figured by Ruedemann (1934, pl. 22). 'Comparison of the species from Ninemile Canyon with specimens of Oaryocaris curvilata from the Garden Pass graptolite beds of the Vinini reveals notable differences. Those from Garden Pass are larger and have a proportionately longer carapace. . Absence of graptolites in the Camoca’m's shale at Ninemile Canyon is difficult to explain, if these shale beds are actually of Early Ordovician age. Early Ordovician age of member B, the 7 00-foot mid- dle Goodwin zone, is established by the abundantly represented trilobite Kainella. Common fossils of the Kamella fauna are: Kainella cf. flagm‘caudus (White) Apatolcephalns finalis (White) Momomia cf. angulata (White) Agnostus sp. Nanorthls ‘multicoetwta (Ulrich and Cooper) Acrotreta cf. eurekensia (Ulrich and Cooper) Obolua sp. Lingulella sp. R. J. Ross, Jr., (written communication, 1956) has recently made zoned fossil collections from Goodwin limestone at Ninemile Canyon, comparing them with Garden City faunas. A collection (USGS, D288 CO) from the lowest 20'feet of member B contains K ainella sp., Apatokephalus sp., and Parabolz'mlla cf. P. urgen- tz'nensis Kobayashi. It represents zone D or possibly an older horizon of the Garden City. From the top 30 feet of the Goodwin (USGS D297 CO) Ross ob- tained Leiostegium cf. L. manitowmses, Hystriowm? sp., Apatokephalus sp., and Pseudom'lem? sp., an as- , semblage with zone D affinities. However, fossils that show affinities to Garden City zone F were collected 250 feet above the base of member B. This assemblage (USGS, D295 CO) listed below might be expected higher in the section, above rather than below that previously mentioned from the top 30 feet. Goodwin limestone collection D295 00 K ai/nella flagrioaudus (White) Apatokephalus sp. Shumardia sp. unidentified olenid trilobite several agnostid trilobites Protopliomerops cf. P. superciliosa Ross Hystm‘curus sp., aft. H. ravnl Poulsen Fossil collections representing either high Goodwin or lowermost Ninemile formation were made from badly disturbed dark—gray limestone in Whiterock Can- yon narrows on the west side of Antelope Valley. These deformed strata appear to underlie beds of the Ninemile. The assemblage includes: X enostegium? cf. X ? belemnum (White), small Leiostegiwm-like pygidia, Obolus sp., and Nanorthz's hamburgemis (Walcott). Zoned collections of Goodwin limestone fossils were made by the late Josiah Bridge of the US. Geological Survey and by G. Arthur Cooper of the Smithsonian Institution in Windfall Canyon, Eureka district (No- lan, Merriam, and Williams, 1956). These came mainly from the lower 130 feet of the formation, in which in- terval two faunal zones were recognized. The lower zone, occupying a few feet of fairly massive limestone at the base of the Goodwin, is characterized by the trilobite Symphysurim and a form related to the genus Eurekia. Brachiopods from this zone include Nanor- this, Obolus, Plectotrophia, and Apheoorthis (Cooper in Nolan, Merriam, and Williams, 1956, p.26—27). As noted by Cooper, the Eurekia-like trilobite and possibly Apheoorthis suggest Late Cambrian, whereas Symphy— surina and N anorthz's are regarded as Early Ordovician elements. Thus it seems appropriate to consider this basal zone, which could include roughly the lower 20 feet of Goodwin limestone, as latest Cambrian or earl— iest Ordovician. The overlying faunal zone at Eureka is unquestion- ably Ordovician, yielding among the trilobites K ainella, Apatokephalus, Symphysurina, Hystrz'curus, and Lei- ostegium and the brachiopods N anorthz's kamburgensis (Walcott), Punctolz'm punctolz‘m Ulrich and Cooper, and a Syntrophina. The lowest or Sympkysm-ina faunal zone with a hold- over Late Cambrian E urekz'a-like trilobite was not rec‘ ognized in the Antelope Valley Goodwin mtion. It is older than the K aiMlla zone, which begins just above 22 PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA the Cam/00am shale (member A) in the Ninemile Can- yon section. Hence ‘the Symphyeum’na zone at Eureka is conceivably equivalent to some part of the Oaryocarz's shale (member A), which seems likewise to straddle the Cambrian-Ordovician boundary. Most of the fossil collections made in the Eureka area came from the lower 130 feet of the Goodwin limestone. At Ninemile Canyon the upper cherty division, 950 feet thick, also yielded few fossils. The Goodwin limestone may be correlated with Kain— ella-bearing beds in the lower part of the Pogonip group in the Ruby Mountains, Nev. (Sharp, 1942, p. 659). It correlates also with the lower part of the Ordovician section in the Ibex Hills, Utah (Hint-2e, 1951, p. 14, 36, 40), where beds with Symphysurina, Kainella and Leiostegium are present (fig. 6). Also correlative with Goodwin is the lower third, and possibly more, of the Garden City formation of Utah up through zone F (Ross, 1949, p. 479—481). Namrthis and K aimlla of the Goodwin indicate relation to the Mons and Chushina formations of the Canadian Rockies (Walcott, 1928, p. 224-226; Ulrich and Cooper, 1938, p. 23—26). Correla- tion with part of the Manitou formation of Colorado is also suggested. Of interest is evidence for correlation of the Mons and Chushina with the Cass Fjord forma- tion of Greenland summarized by Poulsen (1937, p. 65—67 ) . Fauna] evidence given by McAllister (1952, p. 11) suggests that the Goodwin interval is represented in Early Ordovician rocks of the northern Panamint area, California. m FOBn’I‘ION GENERAL Fmrms The term Ninemile formation has been proposed (Nolan, Merriam, and Williams, 1956, p. 27) for Early Ordovician (approximately upper “Canadian”) lime- stone and shale beds cropping out in the vicinity of Nine- mile Canyon, Antelope Range. Type section of the for- mation is located 2 miles southeast of the mouth of Ninemile Canyon (pl. 2, 10c. 56), where the formation rests conformably, and with apparent gradation upon Goodwin limestone and is in turn gradationally over— lain by Antelope Valley limestone (fig. 5) . The shaly Ninemile formation, which is relatively un- resistant to erosion, is inclined to occupy saddles or to form gentler slopes below cliffs and more rugged ex- posures sculptured in the overlying Antelope Valley limestone. AREAL DISTRIBUTION AND LI'I'EOLOGY The most continuous Ninemile outcrops are found in the eastward-dipping section that forms the upper west slope of northern Antelope Range. From Ninemile Canyon the formation has been traced southward a dis- tance of about 4 miles. Along the west foot of the range, smaller exposures lie in a separate westward-dipping. structural block, which appears to represent the west limb of a faulted anticline. Ninemile exposures of smaller extent occur in the Monitor Range, where they are involved in structural complexities at the White- rock Canyon narrows, 1.8 miles west of the Martin Ranch road. At locality 13, about 200 feet of dislocated beds of the Ninemile, dipping at low angles to the west, occupy a position near the base of a thrust plate. As Whiterock Canyon is traversed for half a mile east of locality 13, other exposures of deformed Ninemile are observed in fault contact with Lower Devonian Rabbit Hill limestone. The Ninemile formation comprises medium-gray to olive-greenish-gray limestone beds, with gray to bluish- green partings and interbeds of calcareous shale and highly argillaceous limestone. The impure limestone beds are of fine-grained to porcellaneous texture. Also present are somewhat coarser grained light—grayish to tan crystalline ‘sandy limestones and interbeds several inches thick of fine-grained calcareous quartz sand- stone. In Whiterock Canyon narrows, east of locality 13, much of the exposed Ninemile is dark-gray argil— laceous and calcareous shale. Fossils are fairly numer- ous and well preserved throughout most of the Nine- mile formation at Antelope Valley, often weathering free from the olive-green argillaceous layers that sepa- rate limestone beds. TKIm m At the type section on the east side of Ninemile Can- yon, 550 feet of the Ninemile formation was measured (fig. 5). Elsewhere, as on the Monitor Range side of Antelope Valley, the thickness appears to be consider- ably less and nearer 200 feet, but these figures are un- reliable because of the manner in, which this incompe- tent shaly unit responded to deformation. STRATIGRAPHY Upper and lower limits of the Ninemile formation are gradational. As is well shown in the Whiterock Canyon narrows (100. 13), the more shaly dark-gray Ninemile is'separated from massive cliff-making lime- ’ ’stones of the Antelope Valley by a tan or yellow- ish-weathering argillaceous limestone 7 5-feet thick, carrying the distinctive Orthidiella fauna. The Orthi- diella—bearing limestone beds are regarded as the lowest division of the Antelope Valley limestone, although lithologically they appear to be intermediate. The fauna, however, is more closely allied to that of the overlying limestone than to the Ninemile below. In oanovrcmN SYSTEM 23 the Eureka area, the Ninemile is lithologically diflicult to differentiate from rocks above and below, though it constitutes a readily recognizable faunal unit. AGE AND CORRm'I'ION Early Ordovician age of the N inemile formation is based on a large, well-preserved fauna, as yet only partially studied. A few of the common forms are listed below: Kirkeua vigilant! (Whittingbon) ?Iaoteloidea n. sp. Pliomeropa n. sp. 'Plllaenus n. sp. (large form) ?Pefigurua sp. encrinurid n. sp. raphiophorid -n. sp. Agnostua sp. Hesperonomia antelopemia Ulrich and Cooper Arohaeormu elongata Ulrich and Cooper \ Syntrophopaia puma Ulrich and Cooper Leptella madam-is Ulrich and Cooper Tritoechia ainuata Ulrich and Cooper Rhynchocamara aublaems Ulrich and Cooper Rhmwhoca/mara cf. R. breviph‘oata (Billings) Lingula sp. Heuootoma sp. Eccylioptem sp. RapMatomima cf. R. lafiumbmcata Poulsen (large form) Ulcehmtec, at least two small species ?Protocyclocer¢s foerotei Butts cystoids and cystoid plates numerous Didymoyraptua sp. No ostracodes or bryozoans have been recognized. The small trilobite Kirkella oigilam (Whittington) is diagnostic of the Ninemile. Discovered by Walcott (1884, p. 98) in the Eureka district, this form was identified by him as “Aaaphus? cum'oea Billings”; sub- sequently, the beds under discussion came to be known as the “Aeaphus cum'osus zone.” The generic name “Billingsum” applied to the typical form of this trilo- bite by Ulrich and Cooper (1938, p. 23) was superseded by Kirkella (Kobayashi, 1942, p. 118—121), whereas “Ptyocephahw” of Whittington (1948, p. 567—57 2) was suppressed (Ross, 1951, p. 91) as a synonym of K irkella (Hintze, 1952, p. 181). As noted by Whittington, the peculiar Kirkella is known from “Upper Canadian” rocks over a very wide area in North America, extending from Nevada to Alberta on the west and from Quebec to Arkansas in the east. The Kirkella oigilam zone is recognized west of the Pioche district, where the upper part of the Yellow Hill formation (Westgate and Knopf, 1932, p. 14) bears a fauna similar to that of the Ninemile (Kirk, 1934, p. 454). In the Ibex Hills of western Utah (Hintze, 1951, p. 15—17), comparable faunas with Kirkella are reported to have a vertical range of at least 500 feet (fig. 6). The upper beds of the Garden City in the Randolph quadrangle, northern Utah (Ross, 1949, p. 480) have likewise yielded K irkella cf. oigilans. Similar forms have been observed in Lower Ordovician strata of the Ubehebe area, Inyo County, Calif. Brachiopod studies by Ulrich and Cooper (1938, p. 24, 26) indicate partial equivalence of the Sarbach formation in the Canadian Rockies to the Ninemile. Strata of about the same interval as the Ninemile Kirkella vigilante zone occur also in Texas and the mid- continent (Kirk, 1934). A possible correlation with the N unatam1 beds of northwest Greenland 1s also of interest (Poulsen, 1927,p. 246 ,.342) The Ninemile formation may be roughly correlative with western facies lower graptolite beds of the Vinini, but the upper part of the Vinini is probably no older than Chazyan and possibly younger. In the Roberts Mountains the typical lower part of the Vinini contains Phyllogmptus, Tetragmptus, Didymogmptus, and Cardiogmptm (Merriam and Anderson, 1942, p. 1695). Immediame above this generic assemblage 1n the Vinini type section occur trilobites of the Pliomerope group, also present in the N 1nem11e In Whiterock Canyon narrows (100. 13), the Ninemile includes noncherty dark-gray argillaceous and calcareous shale with Didymogmptue. These shale beds differ greatly in lithology from the overthrust graptolitic shale and chert of the Vinini immediately west of locality 13. Phyllogmptus cf. P. lorz'xngi (White) 13 reported 1n beds of the Ninemile of the Antelope Range by Kirk (1934, p. 455). Whereas the Ninemile includes local grapto~ lite- -bearing shale interbeds, no physical evidence was found to show that this Pogbnip unit intertongues with or passes westward into the lower part of the Vinini as might In theory be expected. ANTELOPE VALLEY LIBSTONE GENERAL FEATURE. Making rugged clifiy slopes in many places, the thick upper limestone beds of the Pogonip group are appro- priately named for Antelope Valley. Conspicuous gray cliffs on the west side of Copenhagen Canyon (loo. 1) illustrate well the erosional expression of this unit, as do similar features on the higher west flank of Antelope Range where the type section of the formation is designated (10c. 58). AREAL DISTRIBUTION AND LITHOLOGY Underlying the less obdurate beds of the Copen- hagen, the Antelope Valley limestone forms much of _ the east slope of Martin Ridge, extending thence south- ward to disappear beneath the volcanic rocks of Butler 24 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA Basin (pl. 2). West of Copenhagen Canyon and north of Whiterock Canyon, Antelope Valley limestone oc- curs in a thrust plate (fig. 4) which has ridden over the Lower Devonian beds of the Rabbit Hill limestone. In fact east of the main exposure of Antelope Valley, a small outlier of this formation appears to rest upon Rabbit Hill limestone at locality 3. To west and north- west the overthrust exposures are terminated by vol- canic rocks. Antelope Valley limestone forms the line of clifl's along the upper west slopes of the Antelope Range, from Ninemile Canyon to Blair Ranch (Segura Ranch). In the Fish Creek Range,'these limestone beds have ex— tensive distribution and may be observed to advantage at Bellevue Peak. The formation is fairly well exposed in the Eureka district, where it has been followed from Goodwin Canyon and McCoy Ridge southward to Windfall Canyon. Northernmost outcrop of this for- mation thus far recognized is at Lone Mountain, where it directly underlies Eureka quartzite; where the Eureka next appears at Roberts Creek Mountain, it is underlain disconformably by Goodwin limestone. The Antelope Valley limestone is prevailingly- a medium to heavy-bedded medium-bluish-gray fairly pure limestone that is fine grained. Calcite 'veinlets are numerous. The deposits often weather to a rough pointed surface. Projecting brownish silicified shell fragments are numerous at several horizons. Although fossils tend to besilicified in all parts of the formation, only a small amount of cihert or j asperoid was observed. THICKNESS On the east side of Martin Ridge near the northern tip the Antelope Valley (10c. 27) measured 1,000 feet thick. True thickness is, however, somewhat greater as the lowermost beds of the formation are not exposed near the valley margin. In all probability the formation exceeds 1,200 feet. A rough estimate of thickness in the steep clifl’y slopes at the type section just south of Nine— mile Canyon agrees with this figure. STRATIGRAPHY In Whiterock Canyon narrows (100. 13), the lower 75 feet of the Antelope Valley is thin-bedded argillace— ous limestone, which appears to be gradational with underlying Ninemile formation. However, this zone, known as the Orthidiella zone (fig. 6), bears a fauna distinct from the Ninemile. The thin-bedded limestone grades upward into the heavy-bedded nonargillaceous middle part of the formation. Whereas in its argil- laceous character the lower 75—foot division is litho— logically somewhat closer to the Ninemile, it differs in weathering tan or yellowish and lacks the dark—gray and bluish-green coloration of the Ninemile. Near its top, the Antelope Valley limestone becomes platy or flaggy and mottled with irregular argillaceous patches that weather tan or limonitic brown. Rela— tionship to the overlying Copenhagen formation ap— pears conformable. Possibility of an undetected break should nonetheless be entertained, for to the north (fig. 7) an important unconformity separates Eureka quartzite from lower units of the Pogonip group. The theoretical horizon of this break is the base of the Copenhagen. On a faunal basis the Antelope Valley limestone may be partitioned in three well—defined zones; these correspond fairly well to lithologic divisions. The faunal Zones are in stratigraphic order as follows: 3. Anomalo'rthis zone 2. Pallisem'a zone 1. Orthidiella zone The lower or Orthidz'ella, zone is especially well shown in the narrows of Whiterock Canyon at locality 13, where it corresponds to the lithologically distinc- tive lower 7 5-foot interval above the beds of the Nine- mile. A large and unique fauna from which species of the Ninemile fauna are absent favors inclusion of this zone with the Antelope Valley limestone. The Orthidiella fauna is significant paleontologically, for it introduces the earliest ostracodes and bryozoans found in the Pogonip group. Characteristic fossils of the Orthidiella zone are listed below : Orthidiella striata. Ulrich and Cooper Orthidiella lonrgwelli Ulrich and Cooper Ortm‘s sp. ‘ Pliomerops nevudcnsis (Walcott) Pliomerops cf. P. barrandei (Billings) I llaenua sp. Asaphus cf. A. quadraticaudatus Billings Ectenonotus cf. E. westom’ (Billings) I schyrotoma cf. I. twenhofeli Raymond Lep‘erditia sp. (small form) slender branching cyclostomate Bryozoa with habit of Coeloclema The Pallisem'a zone embraces some 650 feet of the more massive, cliff-forming part of the formation. Gastropod facies crowded with silicified Pallisem'a longwelli (Kirk) and subordinate large Maclum'tes are characteristic. Palliseria longwelli, a large hyper- strophic gastropod (Knight, 1941, p. 199), was de— scribed by Kirk (1930) as “Mitrospim” on the basis of material that came in part from Martin Ridge. As shown recently by Yochelson (1957), “Mitrospz’m” ap- pears to be a synonym of Pallisem'a (Wilson, [1924). At locality 27 in our measured section the limestone beds of this zone are crowded with P. longwelli, almost 0RDOVICIAN SYSTEM 25 to exclusion of other forms. Commoner fossils of the zone are listed below : Palliseria longwelli (Kirk) Macluritec cf. M; magnus LeSueur- Endoceras sp. Orthocems sp. Orthie cf. 0. tricenaria Conrad Receptaculites mammilla/rts Newberry ?0alathium sp. algal nodules Thick beds containing abundant ovoidal algal nodules are common in the Pallisem'a zone. The nodules, to which the name Gimanella is usually ap- plied, average about 6 millimeters in long diameter and show concentric lamination. They are similar to such bodies occurring abundantly in the Middle and Late Cambrian of the Great Basin region, but uncom— mon above the Middle Ordovician. At Bellevue Peak in the Fish Creek Range and on McCoy Ridge in the Eureka district, strata of the Pal- lisem zone are‘represented by a Receptaculites facies with two distinct types, R. mammz‘llaris Newberry and R. elongatus Walcott, in great abundance. Only R. mammillaris Newberry was found in Antelope Valley, where it is apparently not a common form. The Anomalorthz’s zone occupies roughly the upper 350 feet'of the Antelope Valley limestone, as measured on Martin Ridge. The zone comprises platy and flaggy brown-mottled grayish limestone crowded with small high-spired gastropods, small orthoid brachio- pods, large Leperditia, and hemispherical stony bryozoans. At many exposures the brachiopods are silicified. Beds with concentrically laminated algal nodules similar to those of the Palliseria zone occur here. Characteristic fossils of the A/rwmalo’rthis zone are: Anomalorthis nevadensis Ulrich and Cooper Anomalorthis lonemis (Walcott) Orthis sp. Pliomerops sp. I llaenua sp. Subuh‘tes sp. Lophospira sp. “Murchisonia millem' Hall ?" Walcott Leperditia of. L. bim‘a White stony bryozoans algal nodules cystoid plates AGE AND CORRELATION The large Maclum'tes, Pliomerops, and Beceptacu— lites give the middle part of the Antelope Valley a Chazy aspect in terms of the eastern Ordovician. Equivalent deposits are found in Newfoundland (Kirk, 1934, p. 458). The similarities are especially notable in the Orthz'dz'ella zone, where certain unde— scribed trilobites resemble species in divisions K to M of the Table Head formation (Schuchert and Dunbar, 1934, p. 68—69). The fauna of the Pallisem'a zone with Maclum'tes and various types of Receptaculites is widely recognized in the Cordilleran belt from the Death Valley-Inyo area northward. In fact, several earlier reports of “Pogonip limestone” are based on this assemblage. Representing the upper part of the Antelope Valley interval, the Anomalorthis faunas are becoming known in various parts of the West (fig. 6), such as the Ibex Hills, Utah (Hintze, 1951, p. 19), and upper part of the Garden City and lower part of the Swan Peak quartzite of northeastern Utah (Ross, 1949, p; 479). At Ikes Canyon in the Toquima Range, an unusual sponge fauna occurs in beds of Antelope Valley age (Bassler, 1941 ). These partly argillaceous sponge beds are characterized by Archaeoscyphidae and are reported to yield “Ph'omerops barmadei”. Whereas the lithol- ogy is suggestive of the lower part of the Antelope Valley limestone and the fauna seems to have affinities in Newfoundland with the Table Head, brachiopod studies by Cooper (1956, p. 127) indicate a closer rela- tionship to the Anomalorthis zone. The Antelope Valley limestone is, in the time sense, equivalent to the preposed “Whiterock stage” of G. A. Cooper (1956, p. 7—8, chart 1), the name “Whiterock” having been taken from a canyon in the Monitor Range that joins Copenhagen Canyon (pl. 2). Cooper’s pale— ontologic characterization of the stage is in part as follows: The brachiopod fauna taken from rocks deposited during this stage is characterized by numerous orthids, the early stophom- enids, plectabonitids, and the decline of the Syntrophiacea. Correlative rocks appear in the Arbuckle Mountains of Okla- homa, and the Table Head series of Newfoundland "' * ‘. Equivalents of these beds in Europe are not clearly understood, but some related forms have been taken in Norway and Es- tonia. According to Cooper (1956, chart facing p. 130), the “Whiterock stage” is older than Chazyan. Cooper’s “Orthidiella zone” and “Palliserz'a zone” are in virtual agreement with those of the same name here adopted. In the upper part of the column embraced by the “Whiterock stage” Cooper recognizes two additional brachiopod zones, at “Desmm'this zone” below his “Anomalorthz's zone” and a “Rhysostrophia zone" above. Anomlorthis zone as used in the present paper would seemingly include also the “Dagmar-this zone” of Cooper. COPENHAGEN FORMATION GENERAL FEATURES The name Copenhagen formation is here applied at Antelope Valley to richly fossiliferous limestone, silt— stone, and sandstone beds that occupy an interval be- 26 PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA tween Eureka quartzite and the Anomalorthz's zone of the uppermost Antelope Valley limestone. Type sec— tion of the new formation is on the west side of Martin Ridge, 1 mile southeast of the union of Ryegrass Can- yon with Copenhagen Canyon (10c. 10). These fessilif- erous strata and their correlation have. been discussed heretofore by Kirk (1933, p. 28—31), by Merriam and Anderson (1942, p. 1684) , and more recently by Cooper (1956, p. 126-128). Beds of the Copenhagen are not present in the adjoining Eureka district, where the Pogonip group has been redefined (Nolan, Merriam, and Williams, 1956, p. 23—29) . Accordingly, the Copen~ hagen is not classified as part of the Pogonip group. Am DISTRIBUTION The Copenhagen formation is seemingly restricted to the vicinity of Antelope Valley. It does not extend porthward as far as Lone Mountain, nor has it been recognized to the east in the Fish Creek Range between Antelope Valley and Eureka. Beds of the Copenhagen are best exposed beneath Eureka quartzite along the crest and east slope of Martin Ridge. Good exposures are present also on the west side of the Antelope Range north of Blair Ranch (Segura Ranch), where the for- mation is capped by thinned Eureka quartzite. LITHOLOGY AND STRATIGRAPHY At Martin Ridge the Copenhagen is about 350 feet thick and lends itself to threefold subdivision on the basis of lithology and faunas (fig. 6). These sub- divisions are referred to as member A, member B and member C in ascending order. Whether or not the three divisions can be differentiated lithologically in the Antelope Range has not been ascertained. Member A at the base of the formation is a fine- grained calcite-cemented light—gray quartzitic sand- stone, 25 feet thick, which weathers light grayish brown. It contains abundant straight-shelled cephalopods of the Endocema type, earlier having been referred to as the “Eadooeras sand.” This unit rests with seeming conformity upon the Anomalorthz‘a zone of the upper- most Antelope Valley limestone. Member B, the middle division, with estimated thick- ness of 200 feet, is yellowish-brown to buff-weathering well-bedded impure limestone that is medium to line grained, with argillaceous and silty partings and inter- beds. On fresh break, the limestone is medium gray. A large and varied fauna weathers free from the shaly layers. Member C, the upper division, roughly 125 feet thick, comprises dark-gray silty limestone, calcareous silt— sto'ne, and exceedingly fine—grained calcareous sand- stone. Dark-gray to black carbonaceous shale interbeds are fissile or flaky. Member C appears to intergrade upward with the Eureka quartzite. AGE AND COBREIATION Comparison of the excellently preserved and highly differentiated Copenhagen B and C faunas with those from formations of upper Chazy to about middle Tren- ton age in eastern North America discloses rather close specific resemblances; most of the western species ap- pear, however, to be new. Provisional identifications of fossils from member B of the Copenhagen formation are as follows: Valcourea n. sp. (large form) Rafimzaquina n. sp. Sowerbyites sp. a (small form) Sowerbyites sp. b (large form) Isotelus n. sp. I llaenus cf. I. amen‘canus (Billings) Reoeptaculiteacf. R. occidentalis Salter Stromatotrypa sp. M onotrmm sp. Trematopora sp. Stictoporella sp. Quite characteristic of this assemblage are species of Valcow'ea and Rafinesqmim with a large Becepttwwlz'tes similar to R. occidentalis. One bed contains several genera of massive hemispherical stony bryozoa in abun- dance. Also common are Uyrtocerasclike cephalopods. The fauna of member C of the Copenhagen formation differs sharply from that of underlying member B; few, if any, of the species appear to carry through. Of especial interest. is the occurrence in member C of Olimac'ogmptys associated with the trilobite Loncho- dam. The fauna] changes passing from B to C seem to harmonize with the less calcareous and more silty- argillaceous character of member C. Fossils listed below were collected from member C in the type area of the Copenhagen formation: C'limacograptus cf. 0. pawns (Hall) Strophomena n. sp. Owoplecia n. sp. Cyclocoeua n. sp. Lonchodomas sp. Pterygometopus n. sp. Buma‘stus sp. Illaenus sp. Isotelus sp. (large form) Cryptoldthua sp. g I From beds of the Copenhagen of undetermined hori- zon on the Antelope Range side of the valley, Kirk (1933, p. 33) lists the following forms not recognized by us in the typical exposures of the formation. These are: Remopleufldea sp. Thalcops sp. Eotenaapis cf. E. homalonotoides (Walcott) 0RDOVICIAN SYSTEM ’ 27 Special studies of Copenhagen brachiopods have been made by G. A. Cooper of the Smithsonian Institu- tion. Similarities are noted to species from the Lin- colnshire limestone and Oranda formation of Cooper and COoper (1946, p. 86—89) in Virginia and the Bromide formation of Oklahoma (G. A. Cooper, writ- ten communications, 1947, 1948) . From member B of the Copenhagen formation or the “Yellow limestone,” Cooper (1956, p. 127—128) lists the following brachiopods, most of which are described as new: Camerella umbonata Cooper Gamerella sp. 3 Eoplectodonta altemata (Butts) Diaphragm ponderosum Cooper Lingulaema occidentale Cooper .llacrocoeh'a occidentalis Cooper Multicoatella parallela Cooper Multioostella rectangulata Cooper Owoplecia monitoremis Cooper Sowerbyella sp. 4 Sowerbuites lamellosus Cooper Valcourea plum; Cooper According to Cooper “the zone in question cannot be lower than Lincolnshire or higher than Benbolt * "' *.” A correlation of member B of the Copenhagen formationvwith the Arline formation of Cooper (1956) , in the Southern Appalachians is suggested by his ' brachiopod studies. . In member C of the Copenhagen formation, or “dark shale with Reuschella,” Cooper lists the following brachiopods: Baobia hemispherica Cooper 55mm sp. 1 / Oriatiferma crisiifera Cooper Eoplectodonta alternata (Butts) Glyptorthia sp. 1 . Emperor-this antelopenaia Cooper Leptaena ordovicica Cooper Leptelh'na incompta Cooper Ozoplecia Mmdemn'e Cooper Paurorthia gigantea Cooper Plectorthia obeea Cooper Reuschella vespertlna Cooper Roatricellula angulata Cooper Sowerbyella merrimm' Cooper Sowerbyella sp. 1 and 2 Strophomena sp. 1 According to Cooper this division is correlative with his Oranda formation of Virginia, and may, therefore, be as young as middle Trenton. The richly fossilierous beds of the Copenhagen for- mation are younger than the Anomalo’rthis zone, which characterizes higher strata of the Pogonip group. At Lone Mountain the brown quartzite in the lower part of the Eureka rests upon these Anomalo’rthie-bearing limestone beds; but southward in Antelope Valley, it is the lower part of the Copenhagen that occupies this position, whereas a thinned Eureka, agreeing litho- logically with the light-colored upper part of the Eureka rests upon the Copenhagen (fig. 7). These factors, weighed in conjunction with a rather high content of quartz sand in the Copenhagen itself, strongly suggest that the Copenhagen is a restricted de- positional facies occupying the time-stratigraphic interval of at least the lower brown part of the Eureka quartzite. Further support is given by virtual absence of this lower brown unit, where the Copenhagen is present. As an alternative explanation, it has been suggested that the localized Copenhagen might rep- resent a depositional pocket above a Pogonip-Eureka disconformity, which after truncation was buried by the Eureka. However, the upper part of the Copenhagen is seemingly graditional with overlying light colored Eureka, the lower brown unit of the Eureka is un- recognized, and there is in this vicinity no physical evi- dence of a Pogonip-Eureka unconformity either beneath the Copenhagen or beneath the thinned Eureka over the Copenhagen. Evidence of lateral gradation or intertonguing of Eureka and Copenhagen is needed, but proof of this nature seems unlikely because of lack of outcrop in critical areas. Lateral change of the lower part of the Eureka quartzite into shaly and calcareous deposits may well have taken place locally at many places in the Great Basin. For example, in the Inyo Mountains, Calif., there are sporadic occurrences of limy-argillaceous beds between vitreous Eureka quartzite and the upper lime- stone beds of the Pogonip. At Mazourka Canyon these strata were named Barrel Spring formation (Phleger, 1933, p. 5) and contain a fauna of Trenton affinites, suggesting correlation with the Copenhagen. Such deposits are absent at the base of the Eureka in the adjacent Ubehebe district of the northern Panamint Range (McAllister, 1952, p. 12). EUREKA QUARTZITE GENERAL FEATURES The Eureka quartzite, one of the conspicuous and widely distributed Paleozoic key format-ions of the Great Basin was named by Hague (1883, p. 253, 262; . 1892, p. 54) and later made the subject of special studies by Kirk (1933) and by Webb (1956). Clarence King 1( 1878) in the “Systematic Geology” included what is now called Eureka quartzite in his “Ogden quartzite,” erroneously dated as Devonian. Thugh named by Hague for the town of Eureka, Nev., exposures in that icinity and the northern Fish Creek Range are badly disturbed. Accordingly, the less deformed beds of this 28 PALEOZOIC ROCKS OF AN TELOPE VALLEY, EUREKA AND N Y E COUNTIES, NEVADA 1 2 3 4 Antelope Valley, Antelope Valley, Lone Mountain Roberts Mountains west side at east side at Copenhagen Canyon Table Mountain Nevada formation . Nevada Mlddle Devonian Nevada formation formation Disconformity Oriskany fauna unrecognized Early Devonian Oriskany fauna O'riskany (Oriskany) Pre-Oriskany auna Disconformity /__g disconformity unrecognized Late Silurian Howellella fauna Nevada formation and Lone 2190 ft Lone Mountain dolomite Mountain dolomite unrecognized Lone Mountain Lone Mountain / dolomite 157° “ dolomite ? Top unknown Rabbit Hill 300 ‘H Early Devonian Base ”mm" limestone ‘ ‘ (Helderberg) _ _Pre-Helderberg __j d'smnm'm'ty Faunas of the upper part of the Roberts Mountains formation Roberts Mountains . unrecognized at Antelope Roberts Mountains formation 65°“: "mesmne Valley 741 n formation (dolomite) Chert member Silurian Late Ordovician Chm men'ber R°bert5 MQUMains Hanson Creek . (Richmond) Hanson Creek 1900 ft formation formation 350 " "mm” 315 ft formation (limestone and dolomite) (dolomite) Eureka quartzite 125 ft 1 350 ft Eureka quartzite C?§::gtai5:n 350 ft limestone. siltstone, shale. sandstone ‘7 7 __ p- Pd" ff”. unrecognized {Disconformity unrecognized—‘d '— Amrmahvrthis zone Chert member Anomahrflhis zone Amish” Valley Antelope Valley limestone limestone Hanson Creek formation 560 " (limestone) 498 ft Eureka quartzite Disconformity; no Antelope W- Valley limestone or Nine- mile formation Goodwin limestone FIGURE 7,—Con‘elation diagram showing possible age relations of Ordovician, Silurian. and Lower Devonian rocks in the Antelope Valley area. See figure 2 for location. 0RDOVICIAN SYSTEM 29 unit at Lone Mountain came to be regarded as a stand- ard section (Kirk, 1933, p. 30). In this region, the Eureka is overlain conformably by the Upper Ordo- vician Hanson Creek formation. Relations with un— derlying strata are far less uniform. Whereas at Lone Mountain the Eureka lies on Antelope Valley limestone, to the south the Copenhagen formation is introduced between the quartzite and the Antelope Valley lime- stone. North of Lone Mountain, the Eureka is above a significant disconformity. There are also notable changes in thickness, the quartzite thinning southward and thickening northward from Lone Mountain. AREAL DISTRIBUTION AND LITHOLOGY Eureka quartzite crops out almost continuously above the Copenhagen in westward-dipping fault blocks, which form Martin Ridge (pl. 2). In the Antelope Range, it is exposed below Tertiary volcanic rocks south of Ninemile Canyon near the top of the main east-ward- dipping block; to the southwest the quartzite carries over in several cap-rock erosion remnants of a west- dipping block, which makes the lower west flank of the range. Eureka quartzite forms a considerable part of the surface in the Fish Creek Range (pl. 1), extending northeastward toward the town of Eureka and north- west a short distance into the Mahogany Hills. North of Antelope Valley it reappears in the homoclinal Lone Mountain block and also 20 miles north at Roberts Creek Mountain (fig. 2). Areal distribution of the Eureka quartzite is prob- ably the greatest of any single continuous Paleozoic formation in the Great Basin region, with possible ex- ception of the Upper Ordovician (Richmond) unit, which overlies the Eureka; As at present known with : assurance, it extends from Cortez, Nev., eastward into western Utah and southwestward to the Inyo Mountains of California. In all probability, its northward and eastward extent will ultimately "be shown to be much greater. Absence of Eureka in the southern Ruby Mountains (Sharp, 1942, p. 680) and in the northern Toquima Range (Kay, 1955) indicates that this forma- tion is not a continuousblanket throughout its vast extent. Normal Eureka quartzite comprises pure dense gleaming white sugary varieties and darker, brownish- gray less pure phases. These rocks are orthoquartzite with usually clear, fairly well rounded and in many places well-sorted quartz grains of fine to medium grain size. Petrographic studies by Webb (1956, p. 29—32) indicate that the larger grains have moderate to low sphericity, the finer grains have high sphericity and that there is sometimes minor iron oxide cementation. 665243 045—! Heavy detrital minerals are generally lacking. Cement normally consists almost entirely of silica and only rarely of carbonate where the formation includes lime- stone or dolomite layers. No pitting or frosting of grains has been detected. Sedimentary nature of the Eureka is not uncommonly obscured and original tex- ture obliterated where affected by hydrothermal activity. There are no wholly reliable lithologic criteria that, exclusive of stratigraphy, serve to distinguish Eureka quartzite from other quartzites of the Great Basin 'Pa- leozoic column. Similar arenaceous deposits occur in the Lower Cambrian, the Ordovician Pogonip interval, the Silurian, and in the Devonian (Merriam, 1951). Unlike most of the Eureka the Devonian and Silurian quartzites commonly reveal original calcite or dolomite cement that remains unreplaced by silica. Cambrian quartzites like the Prospect Mountain include minor coarse pebbly facies and are commonly pinkish, maroon, or reddish in color; these characteristics are generally lacking in the Eureka. ‘ THICKNESS In Antelope Valley the average thickness of the Eureka quartzite is about 150 feet, much below normal for the formation as a whole. The Eureka thickens progressively north ward, increasing to 350 feet at Lone Mountain and reaching 500 feet at Roberts Creek Moun- tain, 40 miles north of the Antelope Range. Between the Roberts Mountains on the north and the Inyo Moun- tains of California on the south, thicknesses of Eureka vary characteristically from 300 to 400 feet and are exceeded at only a few places. STRATIGRAPHY As pointed out by Kirk (1933, p. 28) the thicker Eureka sections show two lithologic divisions in many places: An upper white vitreous massive part and a lower phase of slightly darker brownish color, with cross lamination. These lithologic differences are not local, as they have been noted in areas separated as widely as the Roberts Mountains and the’Inyo Moun- tains. Stratigraphy of the Eureka quartzite and of the strata on which it rests involves both disconformity and lateral facies change. Northward from Lone Mountain, diSConformity is the more evident factor, whereas southward from Lone Mountain facies analysis provides an explanation of observed changes. North- ward between Antelope Valley and the Cortez area, Ne- vada, the quartzite rests successively on upper Middle Ordovician, Lower Ordovician, and Upper Cambrian beds. Where the Eureka is unusually thick at Roberts 3O PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA Creek Mountain, it lies disconformably on the lower part of the Goodwin limestone (fig. 7). Missing units of the Pogonip group are the upper part of the Good- win, Ninemile, and the Antelope Valley limestone. The hiatus is much greater at Cortez, where the Eureka lies on dolomite that has the appearance of Upper Cam- brian Hamburg dolomite in the Eureka district, (Nolan, Merriam, and Williams, 1956, p. 30). Evidence for this important unconformity is stratigraphic and pale- ontologic; no significant features of erosion or angular discordance have been noted. No positive indication of’ this stratigraphic break has been found at Lone Mountain or at the Copenhagen-Pogonip boundary in Antelope Valley. . Southward from Lone Mountain, facies changes bring about appreciable rise in section of the quartzite base, as explained previously under Copenhagen formation (p. 27). It is likewise possible that. excessive thicken- ing of the Eureka to 500 feet in the Roberts Mountains may be explainable by descent in section of the lower quartzite boundary, whereby quartz sands took the place of higher carbonate sediments of the Pogonip group. Elsewhere quartz sands, actually appear in the upper part of the Pogonip before normal deposition of Eureka, as shown in the Inyo Mountains of California and as illustrated by the lower part of the Swan Peak quartzite of late Pogonip age in Utah (fig. 6). Significant depositional changes are observed in pass- ing northeastward from Antelope Valley to the Fish Creek Range. Thus, on the east side of Bellevue Peak, within 14 miles of the nearest Copenhagen exposures, strongly crossbedded Eureka quartzite rests on Ante- lope Valley limestone, with no trace of- Copenhagen between. At the Bellevue Peak locality, pre-Eureka emergence is suggested by edgewise mud-breccia be- tween the Eureka and the brown-mottled, grayish upper part of the Antelope Valley limestone. In Antelope Valley the quartzite is relatively thin, fairly uniform, and seemingly conformable. with rocks above and below. It is, moreover, largely the white variety and lacks the lower dark member. At Lone Mountain the Eureka is about 350 feet thick, or over twice that to the south, and is divisible into two mem- bers, of which the lower dark phase is roughly 100 feet thick. It is inferredythat where the Eureka has thinned, as in the Monitor and Antelope ranges, and the lower phase is lacking, the place of the lower phase and part of the upper white phase is occupied by the Copenhagen formation (fig. 7 ). The Chazyan Ammlorthis zone serves as an im- portant datum between Lone Mountain and the area to the south, for at Lone Mountain this key zone underlies the lower brown part of the Eureka and in the Monitor Range it is beneath the Copenhagen formation. In - summary, absence of the lower brown part of the Eu— reka and thinning ‘of the upper light colored phase where Copenhagen is present suggest that the Copen- hagen facies laterally replaces the brown lower part of the Eureka. , Depositional environment of the Eureka is prob- lematic, for normally this formation yields no fossils. Only where vitreous quartzite changes to limy fossili- ferous Copenhagen do we find unmistakable evidence of marine accumulation. Lack of fossils, crossbedding, and the nature of the clean quartz sand itself have sug- ‘ gested that the normal Eureka formed as a wind-trans- ported sediment that accumulated under beach-dune or perhaps even continental conditions. Therefore, it may be reasoned that the carbonate-rich marine Copen- hagen was forming offshore, while concurrently the clean shifting sand of the Eureka proper was deposited within near-shore intertidal and possibly contiguous landward belts. Scarce layers of dolomite in” "the vitreous Eureka quartzite of the northern Inyo Mountains of California, together with an exceptional occurrence of corals at Cortez, Nev. (James Gilluly, oral communication, 1952; Helen Duncan 1956, p. 217) demonstrate that the siliceous deposit interfingers here and there with undoubted marine beds. AGE AND CORRmaATION A late Middle to early Late Ordovician age assign- ment appears reasonable for the Eureka quartzite. Its upper age limit is fixed by the Late Ordovician Rich- mond faunas of the Hanson Creek and its dolomitic equivalents, which accompany the quartzite throughout its distribution. A significant criterion of age is the probable laterally replacing facies relationship wit-h the Copenhagen; if a valid concept, this would date the Eureka as about middle Trenton. Relation of the Eureka quartzite to the Swan Peak quartzite of Utah remains somewhat uncertain (fig. 6). The presence of Anomalorthis suggests that the lower part of the Swan Peak is older than the lowest Eureka (Ross, 1951, p. 21, 27). In central Nevada this brach— iopod genus characterizes the higher part of the Antelope Valley limestone. This would not eliminate possible equivalence of the higher part of the Swan Peak and the Eureka, both overlain by seemingly 001'- relative Richmond strata. As noted by Hintze (1951, p. 20—22), Ordovician quartzite of the Ibex Hills, .Utah, is divisible’ into an upper unit over 500 feet thick and a lower unit about 250 rfeet thick, with a dolomite member between them (fig. 6). It is possible that the lower quartzite may be correlative with the lower part of the Swan Peak, whereas the upper is with 0RDOVICIAN SYSTEM 31 little doubt the Eureka. Fine-grained sandstone or quartzite beds similar to the Swan Peak are found here and there in the upper few hundred feet of the Inyo Mountains Pogonip and elsewhere in the Great Basin. It is, therefore, certain that quartz sand began to accumulate locally in late Pogonip time, before Eureka deposition. Quartzites of possible Eureka age are present in Idaho, although little is yet known of their relation— ships. The Wonah quartzite of British Columbia (Walcott, 1924, p. 9—14; Walker, 1926, p. 31) is a pos- sible northern. Eureka correlative in the Canadian Rockies. Like the Eureka it underlies strata with'a Late Ordovician (Richmond) fauna, but unlike the Eureka it overlies graptolite—bearing Glenogle shale. HANSON CREEK FORMATION GENERAL FEATURES The name Hanson Creek formation was first. applied to Upper Ordovician limestone beds in the Roberts Mountains (Merriam, 1940, p. 10), where the type sec— tion is situated on Pete Hanson Creek. In Antelope Valley this formation rests without obvious discordance upon the thinned Eureka and is overlain gradationally by cherty basal limestone of the Silurian Roberts Mountains formation. ’ Hague (1892, p. 58, 136) regarded beds here called Hanson Creek as the lowermost or “Trenton” part of the “Lone Mountain limestone,” an inclusive division subsequently partitioned into three formations (Mer— riam, 1940, p. 8). Differentiation of these units in the Roberts Mountains, although basically lithologic, is supported by paleontologic evidence. Throughout much of the Great Basin these formational distinctions are on the other hand less clear cut, for this part of the column is generally dolomite and fossils are less nu— merous. In areas of Upper Ordovician and Silurian dolomite, the names Fish Haven dolomite or Ely Springs dolomite have been applied to rocks of the Hanson Creek interval. 7 In the Monitor Range, the Hanson Creek is, like the type section, a limestone but includes graptolitic facies not recognized in the type area nor on the east side of Antelope Valley itself. AREAL DISTRIBUTION AND LITHOLOGY The Hanson Creek is well exposed along the west slope of Martin Ridge and appears in a small area at the junction of Whiterock and Copenhagen Canyons (100. 53). Small outcrops are found south of Ninemile Canyon just below Cenozoic volcanic rocks; several erosion remnants rest upon Eureka quartzite of the westward-dipping block along the west flank of the [medium-, and dark-gray chert granules. Antelope Range. The formation crops out again at Wood Cone near the south edge of the Mahogany Hills, where some of the more fossiliferous limestone ex- posures are located (10c. 76). Unlike the occurrence in the Monitor Range, the Hanson Creek is here partly dolomitic; northward to Lone Mountain and eastward to the vicinity of Eureka, it changes entirely to dolo- mite. The Hanson Creek of the Monitor Range consists in part of dark-gray very fine grained platy and flaggy limestone that commonly weathers light gray and more rarely pinkish. There are scattered fissile shaly part- ings. Individual limestone layers range in thickness from less than 1 inch to 15 inches, averaging about 3 inches. Chert nodules are present, but are rare and widely scattered. The upper 150 feet is heavier bedded than that below and is mottled with irregular ovoidal and vermiform markings of darker gray. North of the mouth of Whiterock Canyon, a 10-foot calcareous sandstone bed lies 40 feet below the top of the formation. The sand- stone is medium light gray with a medium—granular salt and peppery texture given by an abundance of light—, The medium to fine chert grains are well rounded and set in a calcitic matrix that forms about 35 percent of the rock. A fossil bed with abundant small Streptelasma-like corals is found 175 feet below the top of the formation at Copenhagen Canyon, with other fossil—bearing layers near the top. In this area graptolites have been col- lected at several horizons in the platy lower and middle parts, especially just below the crest of Martin Ridge on the east side opposite the mouth of Whiterock Can- yon (loc. 8). THICKNESS A section measured north of the mouth of Whiterock Canyon is 350 feet thick; the total exceeds this figure, for the base is not exposed. At localities along Martin Ridge, estimates of about 300 feet were made in the more broken sections. The dolomitic Hanson Creek at Lone Mountain measured 318 feet, whereas at the type section in the Roberts Mountains it is 560 feet thick. STRATIGRAPHY Change from vitreous Eureka quartzite to platy limestone of the Hanson Creek is rather abrupt and of such lithologic contrast as to suggest a disconformity, though no evidence of post-Eureka erosion was detect- ed. In the type Hanson Creek (Merriam, 1940, p. 11), a zone of lime-cemented sandstone separates vitreous Eureka from the lowest Hanson Creek limestone. Relationship to the overlying Silurian Roberts Mountains formation is one of conformity or gradation, 32 PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA marked by change to a very cherty limestone, which is classified as lowermost Roberts Mountains. Brachio- pods of the Conchirh'um type appear in the upper few feet of the cherty zone at Copenhagen Canyon. The siliceous zone is unquestionably an important strati- graphicmarker, having been recognized here and there in widely separated areas from the Roberts Mountains to the Inyo Mountains of California. In parts of the southern Great Basin, where the middle Paleozoic is largely dolomite and sparingly fossiliferous, it has not been possible to identify the discontinuous cherty zone, and similar carbonate rocks persist upward from the Hanson Greek (or Ely Springs) interval into beds of paleontologically established Silurian age. In these sections it is not possible to demonstrate that the unit in question or the Ordovician system have lithologically definable tops. The resulting stratigraphic dilemma is perhaps significant in connection with failure thus far to fully rwolve some paleontologic questions relating to system assignment of the Richmond interval, which includes the Hanson Creek and equivalents. Judging from preliminary study of sections in Copenhagen Canyon, a stratigraphic breakdown of the Hanson Creek formation may ultimately be possible. The middle and lower parts are relatively thin bedded, sparingly cherty, and bear diagnostic graptolites, whereas the upper part is somewhat heavier bedded, including a sandstone bed toward .the top. The Strep- telaa’ma coral bed lies not far from the middle of the formation in this area. AGE AND CORRELATION Late Ordovician (Richmond) age is established by faunas from Martin Ridge and Wood Cone. These in- clude the graptolite assemblages that characterize the Martin Ridge section and the commoner coral—brachio- pod-trilobite faunas as represented in the Wood Cone area, the type Hanson Creek, and many localities in the southern Great Basin. Thus far no comprehensive study of facies and faunas of the Hanson Creek interval has been undertaken. The Hanson Creek faunas, which introduce abun- dant rugose corals and new groups of brachiopods and trilobites, differ markedly from those of uppermost Pogonip, and seemingly show no intimate aflinity to faunas of the intermediate Copenhagen formation. Abrupt introduction of Richmond-type faunas in car- bonate rocks following the Eureka interval of quartz- ose sand deposition is consistent with profound litho- logic change. In fact, this represents one of the great biologic discontinuities of the Great Basin Paleozdic column, its magnitude alone suggesting disconformity. Graptolites from the middle and lower parts of the Hanson Creek at Martin Ridge (10c. 8).:have been identified by Ruedemann as follows: Climacogmptus tridentatus Lapworth var. mawimua Decker Orthograptus calcaratus Lapworth var. trifidus Gurley Orthograptus sp. Dicellograptus complanatua Lapworth var. omatus Lapworth According to Ruedemann these appear to indicate Late Ordovician of approximately Richmond age. R. J. Ross, J r., of the US. Geological Survey, has recently made, detailed studies of the Hanson Creek graptolite faunas and concludes that they are probably of Ashgillian age in terms of the British succession (written communication, 1956). Ross (written com- munication, 1956) has prepared the following state- ment regarding correlation of the Hanson Creek beds at Martin Ridge: Specifically correlation is with the Polk Creek shale of Okla- homa. However, D. E. Thomas has verified the occurrence of Olimacograptua hastatus T. S. Hall in these beds; in my opinion these may be identical to C. tridentatus var. mazimus Decker, the types of which I have examined. Similarly the Dicello- graptus compares favorably with D. aplm's T. S. Hall, giving the Hanson Creek fauna an Australian flavor. Although there seems to be some disagreement as to precise correlation be- tween Britain and Australia, this would also suggest that the Hanson Creek is’ highest Ordovician. The Hanson Creek coral-brachiopod-trilobite facies are characterized ‘by halysitids, Colummn-ia, members of thesolitary Streptelasma group (Duncan, 1956, p. 226), Rafimsquz'm, Platystrophia, Lepidocyclas, Cryp- tolz'thus, and illaenids. Recent studies by Duncan (p. 222) indicate that Late Ordovician halysitids of the region are distinguishable as Uatenipom. Collections made north of Wood Cone (10c. 76) con- sist mainly of undetermined stony bryozoans and brachiopods, among which are Plaesiomys n. sp., and Rhynchotrema cf. R. argenturbz’ca (White). Cystoid plates are numerous. A collection containing the trilo— bite “Trinucleus” from Wood Cone was determined by by Walcott (Hague, 1892, p. 59) as of Trenton age. This form may well be Cryptoh'thus, a common genus in the Hanson Creek type area. Strata equivalent to the Hanson Creek are assigned to the Ely Springs dolomite in the southern Great Basin. Especially good silicified faunas, comparable to those of the area under consideration, are found in Ely Springs dolomite of the Inyo Mountains of California, where they overlie Eureka quartzite. West of Talc City in 0RDOVICIAN SYSTEM 33 the southernmost Inyo Mountains these faunas include the following: Halyaitea (Oatem'pom) sp. Columnaria cf. 0. alveolata (Gold-fuss) streptelasmid corals, several types Heterorflu's sp. Glyptorthic cf. G. insculpta (Hall) Thaerodonta sp. Lepidocyela (at least 2 species) Platyatrophia sp. Onniella cf. 0. quadrata Wang Zygoapira n. sp. Strophomena sp. Plaeaiomys sp. ,Correlative Late Ordovician faunas occur in the Fish Haven dolomite of Utah, the Montoya of New Mexico, the-Beaverfoot of western Canada (Wilson, 1926), and the Maquoketa of Iowa (Ladd, 1929; Wang, 1949). WESTERN FACIES ROCKS 0F 0RDOVICIAN AGE VININI FORMATION GENERAL FEATURES The Vinini formation of Early and Middle Ordovi- cian age was described in the Roberts Mountains (Merriam and Anderson, 1942, p. 1694—1698), where it occurs only as segments of a major thrust sheet. Sim- ilarly at Antelope Valley, these rocks form isolated thrust remnants. strata of this formation (pl. 1) were at first confused by the Hague Eureka party with lithologically similar Carboniferous rocks, and were accordingly mapped at that time as “Diamond Peak quartzite”. Regional studies indicate that graptolitic strata of Vinini type characterize a western Great Basin sub- province, which contrasts rather sharply in facies with an eastern subprovince in which carbonate deposition prevailed during Ordovician time. An initial aim of these investigations was westward tracing of carbon- ate subprovince rocks, in the hope that their normal depositional relations to the graptolitic rocks might be determined; this objective has thus far not been achieved, for all occurrences of the typical graptolitic facies so far discovered are clearly thrust over other Paleozoic rocks of the area. LITHOLOGY AND OCCURRENCE The Vinini formation includes a wide variety of sed- imentary rocks, ranging from fairly coarse sandstone and siltstone to black shale, bedded chert, and limestone. Chloritized lava flows and tufls are present locally. Near Devils Gate, graptolite—bearing' Sandstone of the Vinini formation as exposed near the mouth of Yahoo Canyon (pl. 1) weathers brown and is well bedded, poorly sorted, and consists mainly of chert and quartz granules. Limon‘itic and argilla- ceous matter is abundant in the interstices. The dark— gray chert fragments that predominate are commonly angular, whereas the quartz grains are generally well—‘ rounded. Interbedded with these sands are dark-gray graptolitic shale beds; the sand contains poorly pre- served shreds of probable algal matter, and graptolite fragments. Some large outcrops of Vinini are mainly brown chert-rich sandstone. Light-gray orthoquartz- ites similar to those of the Eureka quartzite are un- common in the Vinini, but occur locally in the Charnac Basin area. Black shales of the Vinini are smooth, very fine tex- tured, and weather in thin plates and flakes. They com tain graptolites and much finely divided organic mat- ter. Along Vinini Creek some of these are true oil shale. On weathering, the black shale in some places becomes light bluish gray or white, a feature not ob- served in Carboniferous black shale .of the region. Bedded chert, and more rarely fine-grained limestone, are found in association with the black shale. Bedded chert in the Vinini is commonly dark gray when fresh, but weathers light gray or, more rarely, green. The beds contain radiolarians, graptolitic de- bris, and algal matter. They are probably of primary marine origin. Resistant bedded chert makes up a very considerable part of the Vinini throughout‘its ex— tent, and forms most of the more conspicuous geomor- phic features sculptured in this formation. Vinini thrust outliers in the vicinity of Antelope Valley are distributed from the east side of Devils Gate pass to Charnac Basin. . Six groups of Vinini outliers have been mapped or studied; they are situated as fol- lows (pls. 1 and 2) : (1) South of the east entrance to Devils Gate, (2) mouth of Yahoo Canyon, (3) lower pediment slopes of Lone Mountain, (4) Twin Spring Hills at the northeast tip of the Monitor Range, (5) narrows of Whiterock Canyon, 5 miles northwest of Martin Ranch, (6) Charnac Basin on the west slope of the Monitor Range. Small isolated exposures of chert possibly belonging to the Vinini occur in Yahoo Canyon 2 miles south of US. Highway 50 (Ice. 89) and at localities east of Ya- hoo Canyon about 3 miles south of Devils Gate. No graptolites were found in these outcrops. Other chert and shale exposures which are suggestive of the Vinini but which have thus far yielded no fossils, are found 34 PALEOZOIC ROCKS or ANTELOPE at the mouth of Ninemile Canyon in the Antelope Range, in fault contact with the Nevada formation (pl. 2,100. 67). Eastern limit of the Roberts Mountains thrust, as understood at present, is marked by chert and shale of the Vinini south of the east entrance to Devils Gate. In that area the Vinini lies in low-angle thrust contact with underlying Mississippian sandstone of the Chainman and Diamond Peak sequence. The thrust contact dips east roughly parallel to bedding of both Mississippian sandstone and chert in the Vinini of the upper plate. Near the mouth of Yahoo Canyon 1s a large area of Vinini sandstone, chert, and graptolitic shale covered largely by a thin veneer of alluvium. These beds ex- tend southward from US. Highway 50 mostly along the > east side of the canyon. They reappear north of High- way 50 to crop out in patches along the lower west slopes of Whistler Mountain. Rubble-mantled terraces in that belt are in considerable part underlain by Vinini strata. Westernmost outcrops in the Yahoo Canyon-Whistler Mountain belt are mainly brown sandstone of the Vinini, whereas black graptolite shale and chert com- pose the outcrops to the east nearer Whistler Mountain. These chert and shale beds illustrate the light-gray to whitish surface weathering. Small but highly significant outcrops of sandstone, limestone, chert, and graptolite shale of the Vinini occur on the low pediment slopes north, east, and south- east of Lone Mountain. Permian limestone of the Gar— den Valley formation is intimately associated with the Vinini. In that area the lower plate rocks beneath the overthrust include limestone of the Nevada formation and intensely shattered and silicified dolomite which has the appearance of Lone Mountain dolomite. Vinini graptolitic shale and chert of the Twin Spring Hills (pl. 1) are in contact with Garden Valley Per— mian to the north; this relationship appears to be one of unconformity rather than faulting and is in agreement with that at Tyrone Gap. The T“ in Spring Hills Vinini 1s thrust over Pogonip on the south, a relation- ship found also in Whiterock Canyon. Resistant out- liers of chert breccia upon limestone of the Pogonip clearly mark the thrust sole. Discontinuous red colora- tion of Vinini shale beds in the Twin Spring Hills is not limited to that formation. Leaching of volcanic rocks, which probably overlay the entire area before erosion, may be the explanation (Nolan, T. B. ,oral com— munication, 1955). p Vinini strata in Whiterock Canyon narrows mark the southernmost known extent of the major Roberts Mountains overthrust in the Antelope Valley area. The Vinini includes dark-gray graptolitic shale and bedded VALLEY, EUREKA AND NYE COUNTIES, NEVADA chert weathering light bluish gray or whitish, as is typical of the formation. Only a small thrust lobe is exposed west of locality 13 beneath the east edge of the Cenozoic volcanic rocks. Upper plate beds of the Vinini revealed here were evidently thrust over a lower plate comprising Antelope Valley limestone and Nine- mile formation of the Pogonip group, which in turn override Lower Devonian Rabbit Hill limestone. Such complex structural features suggest an imbricate set of thrust sheets beneath the main Roberts Mountains thrust sole. Overthrust beds of Vinini crop out west of Charnac Basin on the west side of the Monitor Range, where the Paleozoic rocks are partly surrounded by the Cenozoic volcanic rocks. The thrust relationship of upper plate Vinini to lower plate Antelope Valley limestone of the Pogonip group is well shown 1 mile west of summit 9,033, near the union of Brock Canyon with Charnac Basin. Attention was drawn to these isolated Vinini exposures by J. H. Wiese and G. E. Knowles of the Rich‘field Oil Co. There are seemingly several thrust slices, for, to the'east, Antelope Valley limestone was in turn thrust over limestone beds of Silurian age. Base of the overthrust Vinini is marked by silicified chert .breccias like those in the Twin Spring Hills and the Roberts Mountains (Merriam and Anderson, 1942, p. 1703). Associated with upper plate chert and grapto- llitic shale of the Vinini is light-gray vitreous quartize re- sembling the Eureka. West of summit 9,033 this quart— zite is overlain by chert and chert breccia. STRATIGRAPHY Continuous stratigraphic order in the Vinini forma- tion has not yet been established. Mapping of Vinini outcrops over 2 miles wide south and southwest of Ty- rone Gap (fig. 2) reveals definite shale, chert—shale, chert, limestone, and sandstone belts that clearly repre- sent stratigraphic zones. However, uncertainties exist regarding vertical order of these zones, for the rocks are intricately folded and sheared. Small pieces of section, a few hundreds of feet thick, can be measured bed by bed, but eventual arrangement of short segments in stratigraphic sequence can be accomplished only by detailed studies of graptolites in conjunction with de— tailed mapping and interpretation of structure and stratigraphy. Preliminary comparison of identified Vinini grapto- lite assemblages with those of established sequences in eastern North America and the Old World shows that the sandstone belts in the Roberts Mountains area are paleontologically older than the belts which consist mainly of chert and shale. Hence, the prevailingly sandstone interval is designated as the lower part of the ORDOVICIAN SYSTEM 35 Vinini and the chert and shale part as the upper part of the Vinini. Field evidence of actual superposition of these two divisions is lacking. A fairly large belt of the sandstone of the Vinini occurs to the west near the mouth of Yahoo Canyon. This belt has not yielded sufficient graptolite evidence to confirm a lower Vinini assignment. Most of the Vinini in the Mahogany Hills and Twin Spring Hills is bedded chert and black shale containing graptolites of the. upper division. Separation of shale and sandstone beds in the Vinini from similar deposits of the Chainman and Diamond Peak sequence is difficult where thrusting brings them into juxtaposition. Discovery of graptolitic shale beds in the northern _Mahogany Hills (Merriam, 1940, p. 28) pointed up this problem and occasioned a prolonged stratigraphic study accompanied by gross lithologic comparisons of regional scope between the Vinini and Mississippian strata. In absence of fossils, bedded primary chert in abundance is accepted as evidence of Vinini age. However,'small amounts of black bedded chert occur locally in the upper part of the Pilot shale. Other lithologic distinctions are treated under Chain- man and Diamond Peak sequence. 'Poor exposures and intense deformation obviate measurement of the Vinini formation. Folded Vinini 12 miles north of Devils Gate crops out in a belt more 4 than 21/2 miles wide; in this folded belt a stratigraphic thickness of at least 1,000 feet is conceivable. AGE AND CORRELATION Previous studies of Vinini graptolite faunas from the Roberts Mountains area (Gurley, 1896; Merriam ? and Anderson, 1942; Ruedemann, 1947) led to the con- clusion that the lower part of the Vinini is of Deepkill age and the upper part of the Vinini of Normanskill age. During this investigation upper Vinini grapto- lites were collected at'the mouth of Yahoo Canyon (locs. 79, 80), northwest of Devils Gate, in the Twin Spring Hills (10c. 84), and on the east pediment of Lone Mountain. A detailed investigation of Vinini graptolites has been initiated by R. J. Ross, J r., of the US. Geological Survey, who prepared the following age analysis in terms of the British succession, based on published identifications of the Vinini forms : Lower Vinini graptolites British zones Dion/enema Tetrayraptus gimme (Hall) _____________________________ 3—5 Tetragraptus quadribrachiatus (Hall) ____________________ 3—5 Phyllograptus cf. P. angwstifoh'ua (Hall) _________________ 4—5 Didymogmptus mtidus (Hall) ___________________________ 4—5 Isograptus gibberulus (Nicholson) Yapeenian of Oardiograptus folium (Ruedemann) Australia ________ 4—5 British zones 3, 4, 5, and 6 represent the Arenig~0f Britain (Elles and Wood, 1918, v. 2, p. 526). Ross has provided the following analysis of the upper Vinini graptolites: Upper Vinini graptolites Brmsh zones Leptogmptus fiaccidus (Hall) var. spim‘fer Elles and Wood, mut. trentommsis Ruedemann ________________ 12—13 Dicmnograptus apim’fer Lapworth _____________________ 9—11 Diplograptua angusn‘foliue (Hall) _____________________ 8—11 Orthograptus calcwattus var. acutus Lapworth __________ 9—10 Olimacograptus bicorm's (Hall) _____ ' ___________________ 9—12 Climaoograptus modeatus Ruedemann __________________ ? Retiogmptus geim‘tziamw (Hall) _______________________ 9—10 According to Ross “The upper Vinini is Llandeillan and Caradocian, but there is no evidence it is Ashgil- lian.” Ross observes that the lower part of the Vinini is correlative with part-of the Valmy formation of the Mount Lewis area, Nevada, with shales of the Hailey quadrangle, Idaho (Umpleby and others, 1930, p. 17— 23), with part of the Glenogle shale of British Colum- bia, and with beds in the Ledbetter slate of eastern Washington. According to Ross: The upper part of the Vinini is correlative with part of the Valmy to the west, Phi Kappa formation of Idaho, graptolite beds in the lower part of the Saturday Mountain formation of . Idaho (Ross, 1959), and part of the Glenogle shale of British Columbia. The problem of correlating the Vinini formation paleontologically with the Pogonip carbonate facies remains unresolved. Factors to be considererd in this connection include occurrence of trilobites of the Plio— merops’ group in the lower part of the Vinini (Merriam and Anderson, 1942, p. 1695), Didymogmptus in dark silty shale of the Ninemile formation in upper White- rock Canyon, and Caz-gamma shale at the base of the Goodwin limestone in Ninemile Canyon. Graptolites occur sporadically in the eastern or car- bonate facies of the Pogonip group. Likewise in the Garden City formation of Utah, Ross (written com- munication, 1956) recognizes Arenig graptolites at least as high as zone H ,(fig. 6), which probably correlates with the Ninemile formation. Ross recognizes Didymo- graptus artus Elles and Wood in the basal Swan Peak of Utah .and at the top of the Ninemile of Antelope Valley. This form is believed to indicate British zone 6 or highest Arenig. The appraisal by Ross indicates the likelihood that “The lower part of the Vinini is not younger than youngest N inemile.” Regarding possible equivalence of the problematic Cam/00am: shale to part of the Vinini on the one hand and to lowermost Goodwin of the Eureka area on the other, Ross states: There is a graptolite zone 3 [British] equivalent in the Garden City. Its position is not certain, though I am sure it is some- 36 PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA where below zone EL I, therefore, see no reason why lower Vinini cannot be equivalent partly to Goodwin as well as Nine- mfle. So far we have nothing to prevent it from being older than Goodwin at Ninemile Canyon (the base of which is younger than at Goodwin Canyon). Graptolites occur also in the Copenhagen formation and in the Hanson Creek formation above the Eureka quartzite. Regarding possible correlation of higher shale of the Vinini beds with these units Ross states: “It the Hanson Creek graptolites are correctly dated as Ash- gillian we do not yet have evidence here that any of the Vinini is correlative with it. Some Valmy collections are, however; and Vinini-like rocks in the Tuscarora Mountains, northwest of Carlin, are definitely of Ashgill age. Therefore, although the upper Vinini seems to be equivalent to no more than Antelope Valley, Copenhagen, and Eureka formations, further collecting will probably produce evidence that it also correlates with the Hanson Creek beds on Martin Ridge.” SILURIAN SYSTEM GENERAL FEATURES South of the 42d parallel, Silurian rocks of the Far West, as understood at present, occur in two separate provinces, each with its own particular depositional and fauna] characteristics. These are ( 1) the Pacific Border province, represented in the Klamath Moun— tains of northern California, and (2) the Great Basin province. The Klamath Silurian comprises siliceous elastic and volcanic rocks and relatively small fossiliferous lime- stone bodies. It is overlain by beds of probable Early Devonian age. ‘Petrologic and faunal relationships of the Klamath Silurian seem to be with Alaska. As rep- resented in Antelope Valley and adjoining areas, the Great Basin Silurian differs sharply, as it is dolomitic in considerable part and, so far as known, devoid of volcanic rocks. Lateral changes from dolomite to fos— siliferous limestone are characteristic. Study of Silurian history in central Nevada con- cerns itself largely with strata described by Hague (1892, p. 57) as the “Lone Mountain limestone.” Ac- tually, a dolomite in the type section at Lone Moun- tain, this division originally embraced rocks of Late Ordovician and Silurian age and has been suspected of including Lower Devonian rocks at the top. In subdividing the original “Lone Mountain lime- stone” of Hague at Lone Mountain and in the nearby Roberts Mountains, three lithologically distinctive formations were proposed by Merriam (1940, p. 10——14) : Hanson Creek formation, Upper Ordovician; Roberts Mountains formation, Silurian; and Lone Mountain dolomite (restricted), Silurian. The name Lone Moun- tain was restricted to a single, fairly discrete dolomite division, in the hope that it would thus be perpetuated in reference to a useful map unit. At Antelope‘Valley, the stratigraphic relations are complicated laterally by disappearance westward of the Lone Mountain dolomite (restricted) and introduction of a higher limestone unit above the Roberts Moun- tains formation. This higher limestone contains Hel- derberg (Early Devonian) fossils. Boundaries separating central Great Basin Silurian rocks from the Ordovician below and Devonian above have been the subject of recent investigations. Ac- ceptance of the Hanson Creek formation with its Rich- mond faunas as Late Ordovician makes it difficult, if not impossible, to draw a mappable Ordovician-Silurian boundary. Where a cherty zone is present at the base of the Roberts Mountains formation, the bottom of the chert becomes a convenient horizon at which to draw the system boundary. Proponents of the Richmond-as-basal-Silurian controversy find satisfac— tion in the observation that throughout the Great Basin an impressive lithologic discontinuity separates Eureka quartzite from overlying Richmond-age Hanson Creek limestone, or its equivalent dolomite formations. The Silurian-Devonian boundary is drawn provision— ally at the pre-Oriskany disconformity, which, at Table Mountain (pl. 1), separates Lone Mountain dolomite from basal dolomitic limestone of the Nevada formation containing Oriskany fossils (fig. 7). Absence from this normal western sequence of the Helderberg Early Devonian or Rabbit Hill fauna suggests either no dep- osition or removal by pre—Oriskany erosion. A third and somewhat less appealing explanation is east-west facies change, whereby the Rabbit Hill limestone changes eastward into uppermost Lone Mountain dolo— mite, which has yielded no evidence of Silurian age above the H owellella zone. \ ' From the standpoint of tectonic history, the pre- Helderberg and pre-Oriskany disconformities at Ante- lope Valley are of great interest. Unconformities sep- arating Silurian and Devonian rocks have been reported throughout a wide area in the Great Basin, extending from southeastern California to Utah. The crustal un- rest so manifested may well have coincided with vul- canism in the Pacific Border province, complete, emergence in the Colorado Plateaus province, and with Caledonian deformation in more distant lands. Paleontologic studies of Great Basin and other Silu— rian of the Far West have been thus far confined to routine and provisional fossil determinations. Lack of understanding of field relations, stratigraphy, and faunas has resulted in confusion of Silurian and De- vonian rocks. These western Silurian strata tend to be dolomitized and, accordingly poor in good fossil material. Nevertheless, well-preserved silicified fos- sils occur locally, lending themselves well to acid prepa- SILURIAN ration. Furthermore, the restricted limestone facies of the Silurian are sometimes highly fossiliferous. Corals are especially abundant in the Silurian car- bonate rocks of this region (Duncan, 1956). Censider- able difficulty .has been experienced, however, in attempting to place the rugose forms in appropriate described genera. Some corals are evidently un- described generically or represent rugose genera not yet adequame diagnosed and figured. Others have pre- viously been recorded only in the Old World. Silurian faunas under investigation in connection with stratigraphic studies of central Nevada include those of the Roberts Mountains, Antelope Valley, and the Tybo district of Nevada (Ferguson, 1933, p. 20); Gold Hill district (Nolan, 1935, p. 17), and Confusion Range in Utah; Death Valley, Inyo Mountains, and ' the Klamath Mountains in California. ROBERTS MOUNTAINS FORMATION GENERAL FEATURES The name Roberts Mountains formation has been ap- plied to strata on the west side of Roberts Creek Moun- tain (Merriam, 1940, p. 11), which rest conformably on limestone beds of the Hanson Creek formation and are overlain concordantly by Lone Mountain dolomite (emended). Type section of the formation lies be- tween the north and south forks of Pete Hanson Creek. In the type area the Roberts Mountains formation, un— like the overlying Lone Mountain, is prevailingly lime- stone. At other localities this formation, together with subj acent beds of the Hanson Creek, has been subjected to nearly complete dolomitization. Strata included in the Roberts Mountains formation at Antelope Valley overlie limestone of the Hanson Creek formation conformably and vary from limestone on the west side of the valley to dolomitic limestone and dolomite on the east side. The Roberts Moun- tains formation is not uniform in its relation to over- lying rocks, for on the east it is overlain with apparent concordance by Lone Mountain dolomite, whereas on the west it is apparently overlain depositionally by the Rabbit Hill limestone of Early Devonian age. Absence of Lone Mountain dolomite in the west, either by un- conformity or facies change, is further explained below. AREAL DISTRIBUTION AND LITHOLOGY The Roberts Mountains formation has been mapped at Copenhagen Canyon and Twin Spring Hills in the Monitor Range and was studied north of “700d Cone in the southern Mahogany Hills. At Copenhagen Canyon (pl. 2) the Roberts Moun- ‘ tains formation is well exposed at the top of the west- ward-dipping homoclinal section forming Martin 37 Ridge. To the west, at the union of Whiteer and Copenhagen Canyons, the formation is exposed in two low knobs. In Rabbit Hill (100. 51), southernmost. of the two knobs, Lower Devonian beds are underlain by this formation, Which extends northward to form the higher part of the adjacent hill whose lower slopes are composed of Upper Ordovician Hanson Creek. A small isolated exposure of graptolite-bearing beds of the Roberts Mountains occurs on the pediment surface along the northeast side of the Twin Spring Hills (pl. 1). Some of these beds may also represent the Hanson Creek formation. N o exposures of Roberts Mountains formation were found in the northern Antelope Range, where the oldest Silurian rocks, exposed at the valley edge are Lone Mountain dolomite. North and northwest of Wood Cone, the formation reappears in a dolomitized condi- tion and extends northwestward along the edge of the Fiahogany Hills for 3 miles. It is also exposed at Lone c SYSTEM ountain where it retains its dolomitic character, but hanges northward to the normal limestone facies in the Roberts Mountains. Northernmost extent of this formation so far recognized is in the Mount Lewis quadrangle south of Battle Mountain, Nev., where it appears to be lithologically similar to the limestone facies at Copenhagen Canyon. Northeast of Wood Cone, in the direction of Eureka, Ltihe Silurian rocks are entirely dolomitic and highly ‘ isturbed. Accordingly, it was not feasible to differ- entiate the Roberts Mountains formation from the Lone Mountain dolomite. Silurian limestone beds, probably representing the Roberts Mountains formation, occur on the west side of Charnac Basin and at Ikes Canyon in the Toquima Range, 18 miles southwest of Copenhagen Canyon. West of Charnac Basin the Silurian limestones appear to be in thrust fault contact with limestones of the Pogonip group. At the Ikes Canyon occur- rence the beds contain Monograptm, [idly/sites, and Rhizophyllum. In Copenhagen Canyon the Roberts Mountains for— mation comprisesdark platy and shaly limestone beds with very cherty limestone at the base. The well - bedded basal cherty member ranges from 110 to about 140 feet in thickness and consists of interbedded dark— gray or slightly bluish gray fine-grained limestone and dark-gray chert that weathers limonite brown. Irreg- ular lenses and beds of chert, one-half to 6 inches thick, make up from one-third to one-half of this member. Above the chert, through the remainder of the forma- tion, the thin-bedded fine-grained gray limestone, though dark gray on fresh fracture, weathers very light. gray with brownish patches. A few dark-gray chert 38 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA nodules are found in the platy limestone member. Subordinate interbeds of coarser textured highly or- ganic partly crinoidal limestone show heavier bedding. THICKNESS Sections of the Roberts Mountains formation meas— ured in Copenhagen Canyon at the low hill (loc. 53), just north of Rabbit Hill are about 600 feet thick of which the basal chert member ranged from 110 to 140 feet in thickness. No measurable section was found in the Mahogany Hills, but at Lone Mountain dolomi- tized beds of the Roberts Mountains are about 740 feet thick. Thickness of the formation increases appreci- ably northward, to as much as 1,900 feet in the Roberts Mountains. STRATIGRAPHY The contact separating Upper Ordovician limestone of the Hanson Creek frOm the Silurian Roberts Moun- tains formation is drawn at the base of a very cherty limestone member well shown in Copenhagen Canyon (10c. 53). The cherty member is also present at Lone Mountain and in the Roberts Mountains. Although the change to chert is abrupt, no evidence of discordance has been observed. Similar cherty limestone beds are present at the bottom of the Silurian section as far distant as the northern Inyo Mountains in California. Where the chert marker is absent, it is diflicult, if not impossible, to objectively define the Ordovician-Silu— rian boundary on a lithologic basis. This is especially true where the entire Upper Ordovician and Silurian section above the Eureka quartzite is dolomitic. At the type section in the Roberts Mountains the upper boundary is conformable, marked by a grada— tional change from limestone and dolomitic limestone rich in corals to blocky light-gray barren sugary dolo- mite of the Lone Mountain (emended). Where both formations are dolomitic, as at Lone Mountain and the Mahogany Hills, the boundary is less definite. The Roberts Mountains formation is, in general, less mas- sive’Or blocky and darker gray than the Lone Mountain dolomite. Fossils are not abundant in either unit where dolomitization has taken place but are more apt to occur in the lower formation than in the Lone Mountain. The Roberts Mountains formation at Copenhagen Canyon has a thickness less than one-third that in the type section (fig. 7). Lithologically there is fairly close agreement with the lower part of the formation in the Roberts Mountains. In the type section several fauna] zones have been recognized, the lower of which is char- acterized by Monograptus, H eliolites, and abundant pentameroids of the Conchidz'um type. An upper zone contains diverse coral and associated brachiopod faunas discussed below. The presence of Monograptus faunas, relatively small thickness, and absence of the upper co— ral faunas suggest that the strata in question at Copen- hagen Canyon represent only the lower part of the Roberts Mountains formation. The remainder, in fact the greater part of the formation, is absent, presumably because of no deposition or post-Roberts Mountains erosion. How much of the formation may be represented paleontologically northwest of Wood Cone (pl. 1) can- not be determined until this unit is carefully studied and mapped in the Mahogany Hills along the east side of Antelope Valley. Progressive thickening of the Roberts Mountains strata to the north, as shown by measured sections at Copenhagen Canyon, Lone Mountain, and Roberts Creek Mountain, suggests that attenuation in Antelope Valley is real, wholly stratigraphic, and not a result of faulting. AGE AND CORRELATION The graptolite Monograptus is found throughout most of the formation at Copenhagen Canyon. Two species have been determined by Ruedemann: Mono- graptus acus Lapworth and M. pandus Lapworth. Ac- cording to Ruedemann (written communication, 1940) they indicate approximate equivalence with the Gala beds of Great Britain or Clinton and younger Niagaran strata of New York State. In these platy or shaly lime- stones other fossils are scarce. In the topmost beds of the basal cherty member indeterminate pentameroid brachiopods, more than an inch long, were collected, thus supporting the Silurian age of these beds in Copen- hagen Canyon. Northwest of Wood Cone the coral H alysites Was found in dolomitized Roberts Mountains strata of uncertain horizon. This form occurs at several horizons in the lower part of the formation at Roberts Creek Mountain, but was not recognized in the upper coral beds of the type section. The coral fa- cies that characterizes the uppermost 200 feet of the formation at Roberts Creek Mountain yields the fol- lowing fossil forms: . Mycophyllum sp. (abundant) Strombodes sp. ?Cladopom (abundant) ?Au8tralophyllum sp. Pyonostylus sp. Dicoelosia sp. H omoeospim sp. Atrypa sp. (abundant) dasycladacean algae The upper Roberts Mountains coral zone is of possible Lockport age. Dasycladacean algae similar to those of the upper coral beds of the Roberts Mountains occur in the higher SILURIAN part / of the Laketown dolomite in the Confusion Range, Utah. Comparable dasycladaceans are pre— sent also in the Hidden Valley dolomite of the Death Valley region (McAllister, 1952, p. 15) and in the middle part of an unnamed Silurian limestone at Mazourka Canyon in the northern Inyo Mountains of California (Rezak, 1959). Monograptus-bearing lower beds of the Roberts Mountains formation are probably equivalent to the lower part of the Laketown, lower part of the Hidden Valley, and lower part of the Silurian limestone at Mazourka Canyon, which last be- gins with a very cherty limestone similar to the basal chert member of the Roberts Mountains formation The Trail Creek formation of Idaho includes correla- tive beds. LONE MOUNTAIN DOLOMITE OCCURRENCE AND NAME The name Lone Mountain limestone was given by Hague (1883, p. 262; 1892, p. 57) to strata between the Eureka quartzite and the Nevada formation at Lone, Mountain, 16 miles northwest of Eureka. Except for a small amount of chert, all beds occupying this in- terval at Lone Mountain are actually dolomite rather than limestone and have yielded few identifiable fos- sils. In the Roberts Mountains (Merriam, 1940, p. 10— 14) the same interval is occupied by three distinctive mappable formations, the lower two of which are mainly‘ limestone. The lower limestone formation, known as the Hanson Creek, is of Late Ordovician age; the overlying or middle limestone is Silurian and has been named the Roberts Mountains formation. Both are fossiliferous. The third or uppermost for— ' mation, a medium- to light-gray blocky dolomite, is lithologically almost identical with the upper and thicker part of the original Lone Mountain limestone of Hague at Lone Mountain (fig. 7). Beneath the upper light-gray dolomite at Lone Mountain lies the thinned, dolomitized, and otherwise modified southern extension of the Roberts Mountains formation, below which is almost. unfossiliferous dolomitized Hanson Creek. The original Lone Moun- tain limestone of Hague at Lone Mountain thus con- tained strata of at least two geologic systems: Ordovician and Silurian. Lack of fossils in the upper light-gray dolomite leaves open the possibility that the Lone Mountain might conceivably include beds of Early Devonian age; if this were true, Hague’s origi- nal Lone Mountain limestone would include parts of three systems. The sections in the Roberts Mountains seem ob— viously better suited for stratigraphic and paleonto- logic study than the barren dolomitic strata at Lone Mountain, because they have greater thickness and are SYSTEM , 39 preeminently more fossiliferous. Type sections of the Hanson Creek and Roberts Mountains formations were accordingly‘designated there (Merriam, 1940, p. 10—12). In coping with the consequent problem of nomen— clature at Lone Mountain at least three courses appeared to be open: (1) complete abandonment of “Lone Moun- tain” as a stratigraphic name; (2) elevation of “Lone Mountain” to group status with three formations, of which only the upper one was represented in its normal or more favorable guise; (3) restriction of the forma- tion name Lone Mountain dolomite to one of the three formational divisions. The last course was elected (Merriam, 1940, p. 13) with the aim of preserving and perpetuating the name Lone Mountain as a useful and objective map term in this region. In so doing, the name Lone Mountain dolomite was applied as emended. to the upper light-gray blocky division, the thickest of the three at Lone Mountain and a fairly uniform divi- sion well exposed also in the Roberts Mountains. Had the Hanson Creek and Roberts Mountains for- mations been represented at Lone Mountain in their normal fossiliferous phases, a reasonable course would have been adoption of the term Lone Mountain group to bracket all three formations occupying the interval of Hague’ s Lone Mountain limestOne. Ideally, it stratigraphic group, whether new or based on subdivi— sion of an earlier defined broad formation, should, if possible, be established where all of its constituent for- mations exhibit facies considered typical or truly repre- sentative. Use of Lone Mountain group, by connotation based on the section at Lone Mountain, would not be especially appropriate in the Roberts Mountains be- cause of lateral facies change and because of probable change in time-rock content. Extended west to the Monitor Range the group name would be even less de- sirable because of greater lithologic and fauna] changes. Introduced westward above the Roberts Mountains formation is the fossiliferous Early Devonian Rabbit Hill limestone facies, a possible time-rock equivalent of uppermost Lone Mountain dolomite as emended. In short, the term Lone Mountain group to be of value in the region here dealt with would have to include units and facies not actually present at Lone Mountain, a usage that would add to the already existing confusion. AREAL DISTRIBUTION AND LITHOLOGY Lone Mountain dolomite has been recognized only on the east side of Antelope Valley. This formation does not appear in the Monitor Range and is not known in the Toquima Range or any of the mountain ranges farther west. The Lone Mountain dolomite underlies Nevada formation at the north tip of the Antelope Range; it extends eastward into the Fish Creek Range , 40 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA and northward beneath the Mahogany Hills to the type area at Lone Mountain. From the Mahogany Hills it may be followed eastward into the Eureka mining dis- trict. Southeast of Eureka only the upper part is well exposed, but at Oxyoke Canyon (Nolan, Merriam, and Williams, 1956, p. 38) the disconformable relationship with overlying Nevada formation is especially well shown. Sections of Lone Mountain dolomite may be seen to advantage on the west side of Roberts Creek Mountain, in the Sulphur Spring Mountains north of Tyrone Gap (fig. 2) and on the west flank of the Diamond Mountains near the Phillipsburg mine. Silurian dolomite of comparable lithologic character and stratigraphic situation occurs widely in the Great Basin, extending from the Ruby Mountains on the north (Sharp, 1942, p. 660) eastward into Utah and southward to Death Valley and the Inyo Mountains. The Lone Mountain dolomite commonly shows rather poorly defined bedding, is massive and blocky-weather- ing, and has a medium to coarse saccharoidal texture. On the weathered surface it is prevailingly light gray; freshly broken faces are sometimes medium to dark gray. Sugary dolomites of the Lone Mountain are readily confused with those of the Nevada formation. On the whole, however, bedding is more clearly defined in the Nevada. Moreover, the dolomite of the Nevada com— monly includes discrete heavy-bedded sequences in which bands of laterally continuous very dark gray or black uniform carbonaceous dolomite alternate with sharply contrasting light—gray layers. Organic traces are relatively uncommon in the Lone Mountain dolomite. Near the base of this formation are beds of coarse crinoidal dolomite, and about 500 feet ‘below the top circumscribed or lenticular dark! gray dolomite patches contain fossils. These dark dolo- mite patches are highly carbonaceous, sometimes fairly well bedded, and occasionally contain silicified fossils and cherty matter. THICKNESS Because of faulting no thickness measurement of the entire Lone Mountain dolomite was made at Antelope Valley. In this respect, however, the type section at nearby Lone Mountain, with thickness of 1,570 feet, is probably representative of the area. The section thickens to 2,190 feet at Roberts Creek Mountain, 20 miles to the north (fig. 7). STRATIGRAPHY At Lone Mountain and Roberts Creek Mountain, the Lone Mountain dolomite is gradational with the under- lying Roberts Mountains formation. Where both units are dolomite, as at Lone Mountain, the line of separa- tion falls within a zone where the color of the rocks changes from predominantly dark gray ofthe Roberts Mountains interval to ‘prevailingly lighter gray of the higher unit. The Lone Mountain dolomite in the Mahognay Hills is overlain disconformably by the lower part of the Nevada formation. Good exposures of this contact may be seen on an east-west spur, 2 miles south of the middle of Table Mountain, at altitude 7,900 feet (loc. 75). Topmost Lone Mountain is a light—gray dolomite mud breccia containing angular dolomite fragments and truncated above by a sharply defined erosion surface. The basal Nevada is a medium—gray, faintly laminated dolomitic crinoidal limestone containing large horn corals characteristic of the Early Devonian Oriskany zone. This coral bed is overlain by fossil beds of the Early Devonian “Spirifer” kobehcma zone. No angu- lar discordance was noted. The pre—Oriskany disconformity at Table Mountain doubtless corresponds to that mapped at Oxyoke Can- yon in the Eureka district (Nolan, Merriam, and Williams, 1956, p. 38), where itlis overlain by the fine- grained Beacon Peak dolomite member of the lower part of the Nevada, in which no determinable fossils have been found. The disconformity was not recognized at Lone Mountain (Merriam, 1940, p. 14), where the boundary between the Lone Mountain dolomite and the Nevada seems to be gradational. A corresponding un- conformity between Silurian Laketown dolomite and the Devonian is reported at Gold Hill, Utah (Nolan, 1935, p. 18) and in the Confusion Range, Utah (R. K. Hose, written communication, 1956). Earlier in these studies it was theorized that the western sequence Rabbit Hill limestone in the Monitor Range might be a time-stratigraphic equivalent of the Lone Mountain dolomite, both resting upon strata as- signed to the Roberts Mountains formation (fig. 7). This theory became at least partially untenable when the diverse Rabbit Hill fauna was demonstrated to be of Early Devonian age, Whereas the upper Lone Mountain faunas with Howellella proved to be Late Silurian. Thus while fossil evidence rules out correla- tion of the Rabbit Hill with all Lone Mountain dolomite below the Howellella zone, a remote possibility remains that the unfossiliferous uppermost few hundred feet of Lone Mountain dolomite may be as young as the Rabbit Hill strata of Helderberg age. AGE AND CORRELATION The Lone Mountain dolomite includes fossil-bearing strata of Late Silurian age. On the whole, however, it is sparsely fossiliferous, unlike the abundantly fos- siliferous limestone of the Roberts Mountains that com- DEVONIAN SYSTEM - ' 41 pose the lower part of the system. Most previously re- ported Lone Mountain fossils, including H alysz'tes, evi— dently came, not from the emended Lone Mountain, but from the lower unit. Dark—gray lenses of dolomite in the upper part of the Lone Mountain at, the type section contain poorly pre- served coral debris. Two silicified fossil assemblages have been found in about the same zone, one at a locality 11/; miles north of Wood Cone (pl. 1) and the other in the Fish Creek Range, 9 miles south of Wood Cone. North of Wood Cone the fossil zone lies 500 to 600 feet stratigraphically below the top of the Lone Mountain dolomite. The common fossils are a bushy colonial coral related to Dispkyllum, the small spiriferoid Howellella, and a spiriferoid of the Lissatrypa type. A late Silurian age is indicated. The dark-gray upper lenses of the Lone Mountain dolomite containing silicified fossils appear to have been loci of especially vigorous organic growth, contrasting sharply in this respect with surrounding lighter gray barren dolomite. Abundance of relict carbonaceous matter supports this View. When the fossil-bearing dolomite is dissolved in hydrochloric acid, oily-appear- ing frothy matter is released. Petroliferous nature of the oily substance was not determined by chemical analysis. It is probable that silicification of the fossils took place at an early stage before dolomitization, thus escaping destruction of shell structure usually attend- ing dolomitic reorganization of the carbonate matter. A species of H owellella similar to that of the upper part of the Lone Mountain occurs near the top of the Silurian Laketown dolomite in the Confusion Range, Utah (R. K. Hose, written communication, 1956; Waite, 1956). These upper Laketown strata are correlative with the Lone Mountain. F inc-textured Sevy dolomite resting uneon-formably on the Laketown was also cor- related by Osmond (1954) with the Lone Mountain dolomite. However, the Sevy is lithologically similar to, and occupies the stratigraphic interval of, the Bea- con Peak dolomite member of the lower part of the Nevada formation in the Eureka district. Hidden Valley dolomite of the Death Valley region (McAllister, 1952, p. 15) is correlative in part with the Lone Mountain but, as delimited by McAllister, includes rocks of early Nevada (Oriskany) age above and Roberts Mountains Early Silurian age below. Hidden Valley Silurian Disphyllum-like corals have smaller corallites than those of the upper part of the Lone Mountain. Lower beds of the Hidden Valley contain Belg/sites and dasycladacean algae like those of the Roberts Mountains formation. Silurian limestone beds at Mazourka Canyon in the Inyo Mountains of California represent undolomitized coral facies of the Hidden Valley; these limestones yield Disphyllum-like corals similar to those of the upper Lone Mountain Howellella zone. Such corals in the uppermost beds of the Mazourka Canyon sequence show internal features more like those of Sanidophg/Zlum Etheridge than Disphyllum and may be either Late Silurian or Early Devonian. Howellella and Lissatrypa-like brachiopods in the upper part of the Lone Mountain suggest correlation with the Gazelle formation of the Klamath Mountains in California (Wells and others, 1959), with Upper Silurian of southeast Alaska (Kirk and Amsden, 1952), and with the Read Bay formation of arctic Cornwallis Island (Thorsteinsson, 1958). Similar species of Howellella occur in the Polish Silurian (Kozlowski, 1929; 1946). More meaningful long distance correla- tion of the Lone Mountain dolomite will become possible when the Howellella zone faunas from this and other western Silurian formations are more throughly studied. DEVONIAN SYSTEM GENERAL FEATURES Devonian rocks of Antelope Valley are about 4,000 feet thick collectively and range in age from Helder- berg Early Devonian to Late Devonian. The entire range in age is not, however, found in a single con- tinuous stratigraphic sequence, for the oldest or Helder- berg-age strata compose a geographically restricted unit recognized only in the Monitor Range. Geologic mapping in the Eureka and Antelope Val- ley areas (Nolan, Merriam, and Williams, 1956) dis- closes surprisingly great east-west lithologic and faunal changes as the Devonian strata are traced eastward from the Monitor Range to the Diamond Mountains (fig. 2). Three Devonian stratigraphic sequences are distinguishable: (1) westernmost Helderberg Devo- nian sequence, (2) normal western Devonian sequence, and (3) eastern Devonian sequence. The westernmost Helderberg-age sequence includes only those Early De- vonian strata to which the name-Rabbit Hill limestone is here applied. The more inclusive western normal and eastern sequences begin with strata of Oriskany age and continue upward to very late Devonian. Super— posed in ascending order, the normal western Devonian sequence includes the Nevada formation, Devils Gate limestone, and the lower part of the Pilot shale. The normal western sequence Devonian rocks have been mapped southward from Devils Gate to the north- ern Antelope Range and were followed eastward into the Eureka mining district, where they merge with the eastern sequence. The normal Western Devonian se- quence is virtually that earlier described at Lone Moun— tain and Devils Gate (Merriam, 1940, p. 22—29). 42 PALEOZOIC ROCKS 0F ANTELOPE The eastern Devonian sequence near Eureka shows the result of great lateral facies change, although com— parative thicknesses suggest little difference in time- stratigraphic content relative to the normal western Devonian column at Lone Mountain and Antelope Val- ley. Occurrence of Helderberg and Oriskany faunas makes the Antelope Valley Devonian column the most nearly complete thus far recorded in western North America. Because of deformation and erosion, the Early Devonian (Helderberg) Rabbit Hill has no established stratigraphic top in the Monitor Range. Moreover, it has not been shown conclusively that normal western sequence Devonian rocks did not at one time extend westward to the Monitor Range. Their absence may be due to no deposition, erosion, or deformation. Missing normal western sequence units could have been cut out by thrusting that caused Ordovician POgonip rocks to override Early Devonian Rabbit Hill (pl. 2, fig. 4). Paleontologic studies were conducted in Lower Devonian rocks of the Sulphur Spring Mountains, where, below the Oriskany zone, occur faunas sim- ilar to those of the Monitor Range Helderberg se— quence. Detailed geologic mapping is needed in the Sulphur Spring Mountains to further elucidate the relation of these fossil-bearing Lower Devonian beds to the Lone Mountain dolomite and to the lower part of the Nevada formation. Reviewing the question of base and top of the De- vonian system in this region, we are still confronted by uncertainties. Base of the normal western sequence is defined by a pre-Oriskany disconformity that locally separates lower beds of the Nevada from the Lone Mountain dolomite. It is likewise probable that the Monitor Range sequence of Helderberg age rests discon- formably upon the lower part of the Roberts Moun— tains formation of Silurian age, cutting out upper beds of the Roberts Mountains and possibly the Lone Mountain dolomite (fig. 7). The pre-Oriskany dis— conformity of the normal western sequence may ex- plain absence of the beds of Helderberg age. In spite of this disconformity, the possibility that the Monitor Range beds of Helderberg age may be a limestone facies-equivalent of uppermost Lone Mountain dolo- mite is not entirely ruled out. Top of the Devonian system is drawn provisionally at an indefinite horizon Within the Pilot shale (fig. 8). Below this horizon the conodonts indicate Late Devonian age for the lower part of the Pilot; the upper part of the Pilot of sections in the Eureka mining district is Early Mississippian. Hague (1892) originally'included the “White Pine shale” in the Devonian system. Later work demon- VALLEY, EUREKA AND NYE COUNTIES, NEVADA strates that only the lower part of the Pilot shale, which is the basal part of Hague’s division, belongs in the Devonian. WESTERN HELDERBERG-AGE LIMESTONES OF THE MONITOR RANGE RABBIT HILL LIMESTONE GENERAL FEATURES The Rabbit Hilllimestone of Early Devonian age is so named for limestone and calcareous shale that make a small outlying hill at the junction of Whiterock Can- yon with Copenhagen Canyon (pl. 2). At this locality (No. 51) is the designated type section of the unit. Al- though contact relations with underlying lower beds of the Roberts Mountains formation are somewhat ob- scure, the absence of upper beds of the Roberts Moun- . tains as well as of the Lone Mountain dolomite point to existence of a disconformity. For stratigraphic interpretation the Rabbit Hill occurrence leaves much to be desired; these relatively incompetent strata are deformed beneath the sole of a thrust fault. No strata younger than Rabbit Hill have been found in this area. AREAL DISTRIBUTION AND STRUCTURE The Rabbit Hill has been recognized only in the M011- itor Range, where its outcrop follows the west side of Copenhagen Canyon for about 5 miles, extending from Ryegrass Canyon northward to disappear beneath the volcanic rocks in the Monitor Range. At the Rabbit Hill type section these beds are about 250 feet thick and dip west about 16°. West of the hill the Lower Devon- ian beds crop out for more than a mile along Whiterock Canyon. Undulant dips are observed, mainly to the west at rather low angles, and few exceed 40° (fig. 4). Minor drag folds are common; at some places bedding plane slippage has caused complex subsidiary flexing of weaker shaly layers between heavier limestone beds. Structural behavior of these dragged beds is in accord with their position beneath the overriding plate of Antelope Valley limestone. At xlocality 3 a thrust out- lier of the Ordovician limestone appears to rest upon deformed Rabbit. Hill. It is probable that minor sym- pathetic thrusts or reverse faults exist within the Rabbit Hill itself. LITHOLOGY The Rabbit Hill limestone comprises dark gray to almost black fine-grained platy and flaggy limestone, calcareous shale, and argillaceous limestone, scattered beds of more coarsely crystalline limestone are as much as 4 feet thick. The heavier beds and lenses are highly organic in many places, consisting in large part of crinoidal, coral, and brachiopod material. In the richly fossiliferous beds much of the material is silicified, DEVONIAN SYSTEM 43 showing limonitic staining on the weathered surface. Some of these rocks, especially the argillaceous phases, weather light gray. On the whole the limestone beds are impure, yielding, on solution in hydrochloric acid, a large residue of insoluble clayey and carbonaceous matter together with silicified fossils. Chert is scarce, but there are a few beds of laminated brownish silici- fied matter, which in thin section has the appearance of medium-grained to very fine silty sand and is composed in large part of comminuted and silicified organic re- mains, including sponge spicules and crinoidal material. THICKNESS Because of the deformation it has not been possible to measure a complete section of the Rabbit Hill lime- stone. At Rabbit Hill about 250 feet of the formation is exposed. A section measured through the Roberts Mountains 'Silurian‘and adjacent rocks, a mile north of Rabbit Hill, shows about 160 feet of the Rabbit Hill limestone, but the exact contact could not be determined. The width of outcrop alone suggests that the Rabbit Hill limestone must considerably exceed the estimate of 250 feet. What appears to be the same fossil bed containing abundant Syfingawon is repeated across the broad out- crop of the Rabbit Hill limestone. Whereas this repeti- tion may be paleontologic recurrence, it seems more probable that the same bed reappears because of sym- pathetic thrust slicing and drag folding. In this area the rather incompetent and locally much deformed beds of the Rabbit Hill occur in the lower plate of a thrust. In accord with structural repetition, the exaggerated Width of outcrop is believed disproportionate to actual stratigraphic thickness of the unit. STRATIGRAPHY Although no actual contact surface was observed, the limestone beds of the Rabbit Hill appear to rest dep- ositionally upon the Roberts Mountains formation, 1 mile north of Rabbit Hill. Not only is the Lone Moun- tain dolomite missing at this boundary, but the Roberts Mountains formation is itself much thinned in com- parison with sections at Lone Mountain and Roberts Creek Mountain ( fig 7). Barring unrecognized fault- ing, we may logically reason either that we are dealing with a major unconformity that cuts out the entire Lone Mountain dolomite together with much of the upper part of the Roberts Mountains or that the hiatus is of a lesser magnitude and the Rabbit Hill is a local lime- stone facies equivalent to a higher part of the Lone Mountain dolomite. Only uppermost Lone Mountain dolomite, about 400 feet thick, need be considered in this connection, for most of this unit up to and including the Howellella zone is clearly Silurian and older than the Rabbit Hill limestone. AGE AND CORRELATION Large collections of well-preserved silicified fossils from the Rabbit Hill type area (10c. 51) were prepared by the acid technique. All represent virtually a single Helderberg Early Devonian fauna. Many of the Rab- bit Hill species are new and undescribed, but a suflicient number are closely related to eastern Helderberg species. Representative Rabbit Hill fossils are listed below: hexactinellid sponge spicules Favosites sp. Oladopora sp. Striatopom sp. cf. S. gwemmsis Amsden Miehelim‘a sp. Pleurodiotyum sp. cf. P. trifoliatum Dunbar Syringawon acumimtum (Simpson) Orthostrophia sp. cf. 0. atrophomenoides (Hall) Dalmtmella sp. (small form) Levenea n. sp. cf. L. subcam‘nata (Hall) Schizora/mma sp. Leptaena sp. cf. L. rhombm‘dalis (Wilckens) Schuchertella 811. (large form) Ohonetes sp. . ,Atrypa sp. Anoplotheca, sp. cf. A. acutiplicata (Conrad) Trematospi/ra sp. cf. T. equistm‘ata Hall and Clarke Merietella 81). (large form) Kozlowskiellma sp. a “Spirifer” sp. cf. “5'.” modestus Hall “Spirifer” sp. of. “S.” swallowemis Foerste “Spirifer” sp. a cf. “S." cyclopterus Hall Tentaculites sp. Platyceras sp. Orthocems sp. (small form) Leonasm‘s sp. cf. L. tuberculatus (Hall) Phaoops sp. Dalmam‘tes sp. Especially distinctive and abundant genera in this .fauna are Lewenea, Kozlmvskiellim, Anoplotheca, Leomspis, and Syringamon. The Levenea is closely related to L. subcam'mzta of the Helderberg Birdsong formation in Tennessee (Dunbar, 1918, p. 743), whereas the Amplotheca resembles A. acutiplz'cata, reported in the Onondaga (Kindle, 1912, p. 84) of the Appalachian region. A similar Amplotlwca occurs also in the Oriskany fauna near the base of the Death Valley Devonian section. Leonaspis cf. L. tuberculatus is fairly close to the eastern Helderberg species (Whit- tington, 1956), whereas Syringawon acuminatum seems to be conspecific with a Brownsport Niagaran species. The new spiriferoid b'rachiopod, assigned to K 021020- skiellz'na sp. a, resembles a recently described Silurian and Early Devonian genus (Boucot, 1957). Species of Trematospim, Schmhertella. and “Spim'fer” sp. a ap? proach Helderberg types. 44 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA Of interest is the peculiar Pleurodz'ctyum, which closely resembles P. tm'foliatum of the lower Helderberg Rockhouse shale in Tennessee (Dunbar, 1920, p. 118). In summary, the fossil evidence suggests an earliest Devonian age; only the Anoplotheca is not harmonious with this View. Pre-Oriskany age of the Rabbit Hill is further borne out by comparison of its fauna with faunas recently discovered below the Oriskany in the lower part of the Nevada in the southern Sulphur Spring Mountains (fig. 2). Species of Levenea, Anoplotheca, and Sym'xn— gawon resemble closely those of the Rabbit Hill. Higher in the same column of the Sulphur Spring Mountains, the Oriskany zone contains large spirifers of the arenosa and murckilsom' types. Thus whereas earliest Devonian Rabbit Hill lime- stone appears to occupy a position wherein Lone Mountain dolomite would logically be expected, it is patently younger than Lone Mountain, except possibly for the uppermost part. The Rabbit Hill limestone probably has a westerly distribution with respect to Lone Mountain dolomite. NORMAL WESTERN SEQUENCE DEVONIAN ROCKS OF ANTELOPE VALLEY NEVADA FORMATION GENERAL FEATURES The name Nevada as applied to Paleozoic rocks of the Great Basin was first used by King (1876). Dis tribu‘tiOn ascribed to this unit on his atlas map embraces areas now known to be occupied by rocks of diverse ages, although by implication King probably intended the term solely for Devonian strata ranging from “Che- mung to Upper Helderberg.” The designation “Ne— vada” was evidently not used in the “Systematic Geology” by King (1878, p. 206, 210, 235, 248). ,In this volume the Devonian strata are referred to as part of the inclusive and now untenable “Wahsatch Limestone”. In the Eureka district, Nev., Hague (1883, p. 264— 266; 1892, p. 63—68) adopted the term “Nevada lime- stone” for Devonian rocks that lie between the “Lone Mountain limestone” and the “White Pine shale.” Stratigraphic and paleontologic studies in areas northwest and west of Eureka led Merriam (1940, p. 14—16) to propose redefinition of the division as Nevada formation. The proposed change called for restricting the name to the lower and middle parts of Hague’s original “Nevada limestone” and designating the re- maining upper part separately as Devils Gate lime— stone. On the basis of Walcott’s fauna] studies, Hague (1883,. p. 265) predicted eventual subdivision of the original “Nevada limestone”, but considered it provi- sionally a single major unit. with “an upper and lower horizon.” Subsequent analysis of the Devonian faunas confirmed the great differences between the lower and upper parts of Hague’s original “Nevada limestone”, even as implied by Hague himself (1883, p. 264, 266). Merriam’s studies do not, however, wholly support Hague’s conception of a “mingling of species through- out the beds” as an obstacle to drawing fairly definite stratigraphic boundaries within the original unit. Likewise subject to modification was the View that cer- tain characteristic species like “Spirifer” pinyonensis and “Bhg/rnchonella casmnea” ranged from the “lower horizon” to the “upper horizon” of the original “Ne- vada limestone." This interpretation probably was founded on a broad species concept, and rather loose identification of poor fossil material, coupled with a lack of criteria by which isolated or partial Devonian sections could be correlated among themselves and so arranged in correct order of superposition. As delimited 'by Merriam, the Nevada formation comprises limestone, dolomite, shale, and sandstone beds of Early and Middle Devonian age resting upon Lone Mountain dolomite and overlain by Devils Gate limestone. More recent studies in the Eureka mining district (Nolan, Merriam, and Williams, 1956) elucidate the great sedimentary facies change in the Nevada rocks from Antelope Valley eastward to Newark Valley. Of special interest are changes from limestone to dolomite and from calcareous shale and limestone to quartz sand- stone passing eastward. Hague (1892, p. 65) listed five localities in the vicin- ity of Eureka where representative sections of the “Nevada limestone” can be examined, without specifi- cally designating one as the type; from these Merriam (1940, p. 15) later selected Modoc Peak (pl. 1), 4 miles west of Eureka, as providing a suitable type section for the redefined Nevada. Because of facies change no in— dividual section of the Nevada formation is wholly satisfactory as a type, but the Modoc Peak column possesses desirable intermediate features of both eastern and western Nevada facies, among which is a western tongue of the Oxyoke Canyon sandstone member. AREAL DISTRIBUTION The Nevada formation is found only on the east side of Antelope Valley (pls. 1, 2). It is well exposed at the north end of the Antelope Range, where it makes up a large block in thrust fault contact with Pogonip rocks to the south. Eastward across Fenstermaker Wash it crops out again in the southern Fish Creek DEVONIAN SYSTEM Range. In the Mahogany Hills, the Nevada is exposed from Combs Peak northwestward through Table Mountain; reappearing at Lone Mountain, it consti- tutes about one—third of the central mountain mass. Throughout the greater part of the Dry Lake arch, the Nevada formation is covered by low-dipping Devils Gate limestone. To the east, in the Eureka district, the Nevada prob- ably occupies more surface area than any other forma— tion; it reappears on the west side of the Diamond Mountains (fig. 2) near the Phillipsburg mine. North— ward the Nevada extends into the Roberts Mountains and beyond in a northwesterly direction to the Cortez district. To the northeast it lies along the Sulphur Spring Mountains through Mineral Hill, and crops out extensively in the southern Ruby Mountains (Sharp, 1942, p. 661). , THICKNESS No unbroken section of Nevada formation was recog- nized in Antelope Valley. At Lone Mountain, where the formation is representative of the Antelope Valley depositional belt, measured thickness is 2,448 feet; this figure compares favorably with 2,550 in the eastern facies at Oxyoke Canyon southeast of Eureka. A measured thickness of 2,200 feet on the west side of Table Mountain is unreliable because of frontal faulting. ' 45 LITHOLOGY AND STRATIGRAPHY The Nevada exposures at Lone Mountain and Ante- lope Valley are collectively unexcelled for completeness of the column and preservation of the fossil record. Lithologically, however, these normal western se- quences differ greatly from those in the Diamond Mountains near Eureka, especially with respect to the lower part of the formation (fig. 8). At Lone Moun- tain (Merriam, 1940, p. 20—24), the formation was for convenience subdivided by means of faunas and lith- ology into lower, middle and upper parts. These somewhat arbitrary divisions are used at Antelope Valley. East of Eureka (Nolan, Merriam, and Williams, 1956, p. 40—48) it was lithologically feasible to sub— divide the Nevada formation into five members (table 2) of which two, Bay State dolomite and underlying Woodpecker limestone, are traceable as map units to the Antelope Valley area, though somewhat modified lithologically. Bay State dolomite member corre- sponds virtually to the upper part of the Nevada, whereas the Woodpecker limestone member is roughly equivalent to the upper third of the middle part of the Nevada. The lower three members of the eastern se- quence have not been mapped through or correlated precisely with the lower middle and lower parts of the Nevada, as represented in the Lone Mountain-Antelope Valley western sequence. TABLE 2,—Compartaon of normal western sequence of the Nevada formationvwith the eastern sequence Normal western sequence at Lone Mountain and east side Antelope Valley Eastern sequence at Oxyoke Canyon, Eureka District Strinaocephalaa zone Upper part or‘the - e vada, 670 it. limestone. Middle part of the Nevada, 1,060 ft. ncidal lenses. ——~::— ————————— ‘—— Lowerpartotthe “Spmfer” kobehuna lone, “Spirifer” Nevada, 718 it. cream submne Thick-bedded dolomite with layers of Dolomite and siliceous limestone, well-bedded limestone with cri- Thin-bedded, (leggy and argillaceous limestone underlain by thicker bedded dolomitic sandy limestone. Bay State dolomite member, 738 it Strinaoce halua zone, Renae Mia sub- zone . Martinia kirki zone with “Leiorhunchue” castanea. Woodpecker limestone member, 387 it. Sentinel Mountain dolomite member, 610 ft. N o determinable Oxyoke Canyon sandstone member, 400 it. ' fossils. Beacon Peak dolomite member, 470 ft. The lower part of the Nevada, about 700 feet thick, consists largely of dark-gray thinly bedded to flaggy richly fossiliferous limestone with argi-llaceous lime- stone or shaly partings. A basal member of the lower part of the Nevada, ranging in thickness from about 15 feet to more than 40 feet, is thicker bedded dolomitic limestone or dolomite of medium- to dark-gray color, weathering very light gray. Whereas the basal mem- ber superficially resembles the underlying Lone Moun— tain dolomite, it carries ' Lower Devonian fossils of Oriskany age (“Spe'rifeW arenosa and “S.” kobeham). 665245 043%; Locally, as at Table Mountain, basal Nevada rests disconformably upon sugary Lone Mountain dolomite (figs. 7, 8). From Antelope Valley to Diamond Val- ley and northward in the Sulphur Spring Mountains, these lowest beds of the Nevada are a distinctive arena— ceous limestone or dolomitic limestone with subangular to well-rounded grains of white to cream-colored apha- nitic carbonate and subordinate amounts of clear quartz grains. Where strongly dolomitiz‘ed, as at Table Moun- tain, the arenaceous character is less obvious because of recrystallization. In all probability these basal are— 46 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA naceous—dolomitic beds of the Nevada correspond to some part of the much thicker Beacon Peak dolomite member, which in the Eureka area is likewise partly arenaceous, containing varying amounts of quartz sand. The lower part of the Nevada in Antelope Valley and at Lone Mountain is roughly equivalent to com: bined Beacon Peak dolomite and Oxyoke Canyon sand- stone members of the Eureka district. Whereas these two members of the eastern sequence are almost barren of fossils, the lower part of the Nevada at Antelope Valley and Lone Mountain is the most richly fossilifer- ous part of the Devonian system in the Great Basin. Westerly tongues of Oxyoke Canyon sandstone mem- ber within and just above the “Spizifer” ping/anemia zone at Modoc Peak and Combs Peak (loc. 78) support this correlation. Oxyoke Canyon sandstone was not recognized at Lone Mountain, but appears again in the southern Sulphur Spring Mountains near the top of the “Spirifer” ping/anemia: zone. The middle part of the Nevada in the Antelope Val- ley region, about 1,000 feet thick, corresponds approxi- mately to combined Sentinel Mountain dolomite member and overlying Woodpecker limestone member. As shown at Lone Mountain, the middle part of the Nevada consists of fine-grained dark-gray well-bedded limestone with lenses of coarse-grained heavy-bedded crinoidal matter, overlain by rather dense fine-grained well-bedded partly siliceous limestone and dolomitic limestone of medium to dark-gray color. These upper middle siliceous limestone beds of the Nevada, corre- sponding to the Woodpecker limestone member at Eu- reka, tend to weather light gray. Limonitic brown mot- tlings commonly represent silicified organic material. \Near Eureka the typical Woodpecker limestone mem— ber is somewhat thinner bedded, with argillaceous to silty calcareous shale interbeds sometimes pinkish in color. On the crest of the Antelope Range at the northern tip, the eastern facies Woodpecker limestone member—though somewhat modified—may be dis- tinguished as a lithologic unit, but northward at Table Mountain, intermediatebetween the Antelope Range and Lone Mountain, these strata of the Woodpecker are greatly changed by dolomitization in a much-faulted area. Similarly at Newark Mountain northeast of Eureka, the Woodpecker member has gone over com- pletely to dolomite and cannot be separated conven- iently from the underlying Sentinel Mountain dolomite member. Upper beds of the Nevada, about 700 feet thick at Lone Mountain and Antelope Valley, correspond to the Bay State dolomite member at Eureka. Largely heavy-bedded or massive, these strata are dolomite of medium-granular to coarse-saccharoidal texture, rang- ing in color from nearly black or very dark gray to light gray. The darker gray phases predominate. Conspicuous bands are produced by thick alternate light and dark layers. The upper dolomite of the Nevada forms rugged blocky staircaselike slopes with low cliffs. Thick dark-gray beds loaded with “spaghetti coral” (Oladopom?) are characteristic, and massive dark and light-gray shell beds contain the large but usually fragmentary and poorly preserved Stringocephalus. FAUNAL ZONES The Viewpoint of the biostratigrapher was adopted in these studies of Antelope Valley Devonian stratig- raphy. Accordingly, the Nevada formation was sub- divided by fossils into four major fauna] zones ar- ranged in stratigraphic order as follows: 4. Stringocephalus zone 3. Martinia [sir-M zone 2. “Spirifer” ping/anemia zone 1. “Spirifer” kobehana zone In terms of lithologic divisions earlier discussed the lower part of the Nevada embraces the “Spirifer” Isobe- lwma zone together with the overlying “Spim'fer” ping/onemis zone; the middle part of the Nevada in- cludes the Mmtz‘m’a kirki zone, and the upper part of the Nevada or Bay State dolomite member occupies the interval of the Stm’ngocephalus zone. The “Spire/er” kobehana zone is represented 1n the northern Antelope Range and at Table Mountain, whence it may be traced southeastward to Combs Peak. Justabove the surface of disconformity with the Lone Mountain dolomite (10c. 75), the lowermost beds of this zone are dark-gray dolomite containing the large “Streptelasmoid sp. a’f (Merriam, 1940, p. 52). This horn coral is characteristic of the Oriskany Early Devonian Trematospira or “Spirifer” arenosa fauna of the basal Nevada, as represented in the Roberts Mountains and the Sulphur Spring Mountains. The “Spirifer” ping/(mama's zone, with its large and diverse fauna is well represented in the belt extending from Table Mountain to Combs Peak and at the north end of the Antelope Range. This zone lends itself to further stratigraphic subdivision. For example, a lower subzone in this area is characterized by abundance of Chonetes W'o.etfiata,' at Lone Mountain this sub- zone yields corals of the genera Radiastmea and Billingsastmea. . Near the summit of the northern Antelope Range (100. 57), the modified Woodpecker limestone member carries a rich M art/mm kirk-7} fauna with “Leiozhynchus” castanea and a large platelike member of the Receptaw— lites group in considerable abundance. At a much low- DEVONIAN SYSTEM 47 er horizon, fragments of Receptaculites occur in the lower Oriskany zone of the Nevada at Lone Mountain. These interesting holdovers from the Ordovician are known also in the Late Devonian of New Mexico (Stain- brook, 1945, p. 3, 11; 1948, p. 786), in the New York Tully (Cooper and Williams, 1935, p. 855), in the De- vonian of Australia (Teichert, 1949, p. 11, 33) and in Europe. Coral ledges with H ewago/mmia are restricted to this part of the column in the Antelope Range. Where the middle and upper parts of the Nevada are dolomitized and badly faulted at Table Mountain, the Maw-timid lair-hi zone faunas were not found. Only at Table Mountain was the Stringocephalus zone recognized, for in the Antelope Range the Nevada strata above the Woodpecker member appear to have been removed by erosion. Poorly preserved large brachiopods, at least some of which are Stringocephahw, range through about 400 feet of massive dolomite at Table Mountain; this is roughly the thickness of the Stfingocephahw zone in the type Bay State member east of Eureka. AGE AND CORRELATION Lowermost and uppermost faunal zones of the Nev- ada formation are well dated in terms of New York and European standards. A satisfactory tie with the Or- iskany Early Devonian of New York is provided by spirifers of the “S.” arenosa and “S” murahz'som' types found in the basal Nevada, whereas a Givetian late Middle Devonian age is indicated by Stfingocephalm and Remaelandz'a from the upper part of the Nevada. In the interval between these two well-fixed stages, sound distant correlatiOns are not yet possible on a pa— leontologic basis, for above the beds with “Spim'fer” arenosa almost no diagnostic lower and middle Nevada species have been reported outside of the Cordilleran belt; in fact, most of the lower Nevada species remain unrecognized beyond the central Great Basin. Nevada faunas of one horizon or another have in re- cent years become known at widely scattered localities in the Great Basin, but only in the central part of this region has a full sequence of its faunal zones been rec- ognized. Stringocephalus stands as the one zone indi- cator found at nearly all localities in the Great Basin Where rocks of Nevada age have been studied. Future mapping and collecting will no doubt extend the geo- graphic range of other Nevada faunas, but in these un- dertakings facies change and nondeposition should be considered in connection with problems of Devonian faunal distribution. North and northeast of the Sulphur Spring Range only the upper middle and upper parts of the Nevada have been identified 'by fossils. Thus Martinia lair-7673 and Stringocephalus represent the formation in the southern Ruby Mountains (Sharp, 1942, p. 663—664); on the east at Gold Hill, Utah the Simonson and Guil- mette formations (Nolan, 1935, p. 20—21) carry Mart- im'a and Stringocephalus. But neither at Gold Hill nor in the Ruby Mountains have the “Spirifer” piny- (mesz's or older Nevada faunas thus far been recognized. Absence of these assemblages does not necessarily indi- cate that deposits of early middle and early Nevada age are absent from the areas in question. Our stratigraphy and mapping between Antelope Valley and the east Eureka belt show eastward disap- pearance of lower and lower middle Nevada faunas by facies change. The terms easternfacies and western facies are accordingly adopted to express these differ- ences in the study area. In a sense, the results of our reconnaissance studies give these facies terms a broader geographic meaning, for the eastern facies, as seen near Eureka, appear to extend more or less continuously from central Nevada into Utah. The eastern facies of the lower and middle parts of the Nevada are predominantly dolomite, with subordi- nate amounts of sandstone or quartzite, and usually are almost devoid of fossils. The western facies, on the other hand, probably representing about the same time— stratigraphic interval, comprises highly fossiliferous platy or flaggy impure argillaceous limestone with a dolomitic limestone member near the base. Lower dol— omitic limestone beds of the western facies bear the Early Devonian “Spifl'fer” kobeham and “Spirifer” arenosa faunas. These assemblages have not been found in the eastern facies Beacon Peak dolomite mem- ber where they would be expected. The Middle Devon- ian “Spirifer” pinyommsis fauna is also unrecognized in eastern facies strata, having been searched for es- pecially in the interval which brackets the upper part of the Beacon Peak and the overlying Oxyoke Canyon . sandstone member. ‘ From the Eureka district eastward to Utah, a dis- tance of 125 miles, little is kn0wn in detail of the Nevada formation. Presence of Stringocephalus near Monte Cristo (fig. 2) shows that the upper part of the Nevada reaches the White Pine district. Late Devonian faunas described and listed from the White Pine and Ely dis- tricts (Meek, 1877 p. 25—48; Hall and Whitfield, 1877, p. 246—251; Spencer, .1917, p: 25) .actually pertain al- most entirely to the Devils Gate limestone rather than the emended Nevada limestone. Dolomite beds that underlie the Devils Gate in these districts have thus far yielded few fossils, and while almost certainly repre— senting eastern facies of the Nevada formation, are of a type readily confused with Silurian Lone Mountain dolomite. 48 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA Stfingooephalus occurs here and there in dolomite beds at other localities in eastern Nevada, where the lower part of the same dolomite column doubtless in— cludes eastern facies of the middle and lower parts of the Nevada. Although it may be inferred that the east— ern facies of the middle and lower parts of the Nevada thins somewhat passing eastward from Eureka through the White Pine and Ely districts, our present sketchy knowledge does not justify the conclusion that these rocks pinch down appreciably or are overlapped east- ward by the higher Devonian strata, as was once believed. - Light is shed upon the nature and distribution of eastern sequence dolomite of the Nevada by current studies in the Confusion Range, Utah (R. K. Hose, written communication, 1956), where thick dolomite units underlie a Devils Gate limestone equivalent. Cor- responding to the Sevy dolomite, Simonson dolomite, and at least part of the Guilmette at Gold Hill, Utah (Nolan, 1935, p. 18—21), these Lower and Middle Devonian strata of the Confusion Range are approxi- mately equivalent to the eastern sequence of the Nevada formation in the central Great Basin. In fact the fine- grained Sevy dolomite agrees lithologically with east- ern sequence Beacon Peak dolomite member at Eureka, which is correspondingly almost barren of fossils. Both Beacon Peak and Sevy rest unconformably on dolomite assigned to the Silurian system. These factors, considered in the light of probable equivalence of barren Beacon Peak and the richly fossiliferous Oriskany age lower part of the Nevada in the western sequence (table 2), seemingly controvert a correlation of the Sevy and Lone Mountain dolomite as suggested by Osmond (1954). The sparingly fossiliferous Simonson and the lower part of the Guilmette in the Confusion Range seem to be correlative with the middle and upper parts of the Nevada formation. Our meager knowledge of the geographic extent. of \_ lower Nevada faunas suggests that these faunas are distributed southward and southwestward with respect to center of the Great Basin. Considering the lowest faunas, those with spirifers of the “S.” arenosa, “S.” marchisoni, and “S.” kobehana types, we find them to range geographically from the Sulphur Spring Range of central Nevada to the Ubehebe district of Inyo County, Calif. (McAllister, 1952, p. 17), 170 miles southwest of Antelope Valley. Rocks lithologically similar'to both eastern and western facies of the Nevada formation occur also in the Yucca Flat-Frenchman Flat area (Johnson and Hibbard, 1957), 175 miles south of Antelope Valley. These strata bear the “Spirz'fer” ping/anemia assemblages, but have not yielded Early Devonian indicators of the lowermost Nevada. Ab— sence of the pinyonemz's faunas above the Early Devo- nian kobehana beds at Ubehebe, 100 miles west of Yucca Flat, is perhaps explainable by facies, for argillaceous limestones of the type normally host for this assem- blage, have not been observed in the Ubehebe or Inyo sections. Absence of the M (tr-timid lair-hi fauna in the southern Great Basin may be explained either by facies or in- adequate collecting, but the ubiquitous Stringocephalus is well known in that region, having been found north of Las Vegas, at Ubehebe, and in the southern Inyo Mountains of California. Unlike the older Nevada faunas with respect to geo- graphic distribution,-distinctive elements of the upper middle and upper parts of the Nevada occur north and east of the central Great Basin, ranging in fact to arctic Canada. Northern relationships are most evi- dent Where faunas of the Martinia kirki and String- ocephalus zones are concerned. Medium-sized smooth spiriferoids possessing external features of JIM-timid McCoy and Martiniopsis \Vaagen reached a peak during the medial Middle Devonian in the northern Cordilleran belt and in the Great Basin. Their time of greatest evolutionary differentiation and geographic spread immediately preceded that of the larger Stm’ngocephalus. These Mamtinia-like brachi- opods require further comparative study and classifica- tion based in large part, on internal features, because of the homeomorphy manifested by smooth brachiopods of this kind. Until such studies are made, use of the name Maritime in a very loose sense has been adopted (Merriam, 1940, p. 85; George, 1927). Beginning locally in the upper part of the “Spirifer” pinyonensz's zone with Martinia andifera, these forms become abundant in the Martinia kirki zone and dis- appear in the upper part of the Devils Gate limestone with M. moademis. At Combs Peak Martina?» un- difem occurs just beneath a thin westerly tongue of the Oxyoke Canyon sandstone member (loc. 78, table 2). Martinia-like brachiopods show a comparable de— velopment in western Canada from Great Slave Lake to the Arctic Ocean along the Mackenzie Valley. As reported by Warren (1944, p. 126—128), Warren and Stelck (1949, p.139—148), and Merriam (1940, p. 77, 85), the Mackenzie Valley Martinia-like brachiopods range upward from the pre-Strz'ngocephalus Hare In- dian River shale and Pine Point limestone through the Stringocephalus zone to the Beavertail limestone and the Late Devonian Fort Creek shale. Among the Martian-like brachiopods reported from western Can- ada are “Martinz'a meristoides Meek” and “M. richard— 80ml (Meek) ” in the Hare Indian River beds; “M. mew-21 DEVONIAN SYSTEM 49 stoides,” “M. occidentalis,” “M. richardsom',” and “M. kirki?” are reported from the Pine Point. “M artim'a meristoz'des” occurs in the Stfingocephalus-bearing Ramparts limestone, “M. cf. occidentalis” and “Mar- tmia? franklini Meek” in the Beaver-tail, and “M. 0002'- dentalz's” in the Fort Creek. Brachiopods of the “Leiorhymhus” castomea type locally outnumber the “martinias” in M. kirkz‘ beds of the Great Basin. This is especially true of exposures east of Eureka. In Canada brachiopods of the same general type are numerous; in fact, Meek’s type of the species (Meek, 1867) is reported to have come from Anderson River. There is, however, some uncertainty regarding the horizon from which the type was actually collected. According to Warren and Stelck (1949, p. 144), it may have come from Hare Indian River-shale below the Stringocephalus zone. Such is the strati- graphic position of our Nevada representatives of this brachiopod group. There are reports of “castanea” in the Mackenzie Valley above Stringoceleus-bearing Ramparts limestone, as in the Beavertail and Fort Creek (Warren, 1944, p. 107, 112; Warren and Stelck, 1949, p. 142, 143). Thus far we have not recognized brachiopods of this kind in the Great. Basin above the Stringocephalus zone; that is, in the Devils Gate limestone. Presence of the compound coral H ewagomm'a in the Hare Indian River shale of the lower Mackenzie Valley (Warren and Stelck, 1956, pl. 1) agrees stratigraphi- cally with its occurrence at Antelope Valley, where in the Martinia kirkz' zone it forms coral lenses locally. Of all Devonian faunal zones, in the Great Basin, that marked by the distinctive late Middle Devonian brachiopod Stringocephalus has the greatest geographic extent. In the Cordilleran belt this key brachiopod is distributed from the Las Vegas area in southern Nevada and from the Inyo Mountains of California to the Ramparts of the lower Mackenzie Valley in arctic Can- ada, a meridional distance of 2,500 miles (Kirk, 1927, p. 219—222) . Eastward from Antelope Valley, String- ocephalus beds extend to the White Pine district and thence to Gold Hill and the Thomas Range, Utah. Of special interest is discovery of another large tere— bratuloid Bensselandia at the base of the Stringoce- phalus zone in the Alhambra Hills southeast of Eureka, Nevada; its stratigraphic position agrees with that of the same distinctive genus in the Ramparts limestone of the lower Mackenzie Valley (Warren, 1944, p. 116). Remselandz’a appears to have a very restricted strati- graphic range in western America. Its presence in the Cedar Valley limestone of Iowa (Cooper and Cloud, 1938, p. 446; Cloud, 1942, p. 99; Stainbrook, 1941, p. 43) unaccompanied by Stringocephalus supports a late Mid- dle Devonian age for the formation in Iowa. Province relations of the early Middle Devonian “Spirz'fer” ping/anemia faunas are least understood of all in the Great Basin Devonian, in spite of their abun— dance and great taxonomic diversity. Unlike later Middle Devonian faunas of the Nevada formation, un- certainty exists regarding presence of pinyonensz’s zone faunas in the. Cordilleran belt of western Canada. Faunas believed correlative with the pinyonemis zone are reported by Warren and .Stelck (1950, p. 76—77; 1956, p. 5, pl. 1) in the Hare Indian River shale and referred to the “Radiastmea arachne zone.” As listed, these faunas seem to include a mixture of species, some to be expected in the upper Nevada Martinia Icirlcz' zone, others in the lower Nevada pinyommis zone where the typical Radiastmea arachm occurs. Between faunas of the “Spirifer” pinyonensz‘s zone and those of well-known Middle Devonian formations in eastern North America there is general lack of close similarity. On the other hand it is recognized that coral assemblages of facies comparable to the eastern Onondaga are present in the lower part of the Nevada, at horizons which cannot. be far removed in time from that interval. Preliminary comparison of corals in the middle and lower parts of the Nevada with those from eastern Onondaga limestone suggests that the resemblances are more expressive of similar ecologic adaptation and perhaps comparable stage of evolution than close genetic aflinity. Provincial relations of “Spirifer” pinyonemz'x faunas in the lower part of the Nevada are conceivably to be sought within or adjoin- ing the Pacific province, possibly to the south. Lowermost Nevada faunas of Early Devonian Oris- kany age and the Rabbit Hill faunas of Helderberg age are unreported in western Canada. Possibility of find- ing Early Devonian fossils in the “Bear Rock forma- tion” below the “Badiastraea arachne zone” is, however, considered by Warren and Stelck (1950, p. 77). DEVILS GATE LIMESTONE GENERAL FEATURES Type section of the Devils Gate limestone (Mer- riam, 1940, p. 16) is at Devils Gate pass, 71/2 miles northwest of Eureka. The name “Swallow Canyon” given the gorge in 1858 by its discoverers, the Simpson party, is lost in oblivion. Geological observations and fossil collections made at “Swallow Canyon” (Devils Gate) by the explorers, are the basis for perhaps the earliest published record of far western Devonian rocks. In 1880 fossils were collected here by the Hague party, to whom the locality was known as “The Gate” (Hague, 1892, p. 83). The narrow curving de- .50 PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA file, boldly sculptured in gray Devonian limestone, ac— commodates eastward seasonal drainage from Kobeh Valley to Diamond Valley; since the discovery by Simpson it has been traversed by an important cross- country route, known today as the Lincoln Highway (US. Highway 50). So situated, Devils Gate became a popular collecting site for the itinerant fossil hunter; as a result, free—weathering specimens, once abundant, have become scarce. Overlain by Pilot shale (lower “White Pine shale”) and underlain by Nevada formation (emended) the Devils Gate limestone corresponds to only the upper part of Hague’s (1883; 1892) “Nevada limestone.” When the Devils Gate was proposed as a separate for- mation by Merriam (1940, p. 25) emphasis was placed on paleontologic criteria. Subsequent work in the Eureka vicinity (Nolan, Merriam, and Williams, 1956, p. 48—52) amplifies the fossil data and, in pointing up rock, distinctions, has demonstrated mappability of the Devils Gate-Nevada lithologic boundary. AREAL DISTRIBUTION The greater part of the surface in the Mahogany Hills (pl. 1) is formed by Devils Gate limestone, which has been mapped southward from the type area to Table Mountain and Combs Peak, and southeast t0 Modoc Peak. The Nevada—Devils Gate contact is ex- posed at few places because of low bedding dip. Relatively small erosion remnants of the overlying Carboniferous strata remain on the flanks of the uparched Mahogany Hills, and scattered outliers of Vinini formation suggest that large areas of present Devils Gate outcrop were probably occupied by the overthrust sheet during earlier stages of geomorphic development. Devils Gate limestone is absent from the Monitor Range, and its western limit of exposure is in, the con- spicuous bedrock outlier (10c. 88) northwest of Bur- lington Canyon. Devils Gate limestone, together with uppermost Nevada, was apparently stripped by erosion from the Devonian block at the north end of the Antelope Range. , To the north this formation was not previously differ- entiated from Nevada formation in the Roberts Moun- tains (fig. 2), though it is represented in that region and in the northern Sulphur Spring Range (Winterer, E. L., 1959, oral communication). It. is present also to the northeast in the Ruby Mountains (Sharp, 1942, p. 664). Strata of the Devils Gate crop out on both east and west sides of the Diamond Mountains. At Newark Mountain on the east, they form the impressive upper sheer clifl'y part of the east-facing scarp; on the west, this unit. is well exposed near the Phillipsburg mine. At the south end of the Diamond Mountains, Devils Gate limestone beds were mapped separately in the Alhambra Hills, at Silverado Mountain, and at Sen- tinel Mountain. Devils Gate limestone crops out with characteristic prominence in the White Pine (Hamilton) and Ely mining districts, where it has not been differentiated from “Nevada limestone” in the sense in which this term was earlier used. Limestones of Devils Gate age, and to some extent Devils Gate rock type, are recog- nized in the southern Shell Creek Range (Merriam, 1940, p. 39), and more distantly at Yucca Flat in southern Nevada (Johnson and Hibbard, 1957). Other remote occurrences are treated below under “Age and correlation.” LITHOLOGY The Devils Gate is largely medium-dark- to dark- gray well—bedded limestone and ranges from thin and flaggy to heavy bedded. In general, thick-bedded massive-weathering phases predominate, thicker beds ranging from 21/2 feet to about 5 feet. Formation of clifl’s is more characteristic of the Devils Gate than other formations of the region, with exception of the Ordovician Antelope Valley limestone. Marked by in- cipient caves and solution hollows, the Devils Gate cliffs provide a notable geomorphic contrast with the less precipitous slopes and ragged staircase effect pro- duced by erosion of underlying dolomite of the Nevada. Viewed from a diStance, the cliff-forming members seem massive and homogeneous; this appearance may be deceptive, for at close range the sheer faces some- times exhibit distinctly platy or flaggy bedding lines. Argillaceous limestone beds recur through the Devils Gate section. They have thin clayey partings or inter- beds and argillaceous mottlings. Where the limestone is more than ordinarily argillaceous, parting or bedding tends to be thinner. Pinkish coloration is characteristic of the argillaceous matter and may also pervade the contiguous purer limestones. Variation in gray color of the nonargillaceous lime- stone is doubtless a function of carbon content. Weathering sometimes produces light—gray surface col- oration with a suggestion of blue. The predominant dark-gray limestone beds are fairly pure, have a medium-grained to fine-grained or aphan- itic texture, and are brittle. Dark-gray chert nodules are scattered in the upper 250 feet of the formation but are rarely found below. The Devils Gate is normally, but not always, lime- stone; this usually serves to distinguish it from the Nevada formation, which is ordinarily dolomite in its upper part and may be almost entirely dolomite. The DEVONIAN SYSTEM 51 lower part of the Devils Gate is the most susceptible to magnesian alteration. Near its base, magnesian limestone or primary dolomite beds sometimes alternate with limestone. Higher in the section, dolomite occurs in patches and more rarely as rather extensive irregular bodies that are readily confused with dolomite of the higher part of the Nevada formation. In some places these local bodies of dolomite are probably a result of relatively late hydrothermal activity, the magnesian so- lutions having moved upward along faults. Depositional features, both mechanical and organic, serve to distinguish carbonate rocks of the Devils Gate from those of otherwise similar formations. Es- pecially distinctive are the coarse mud breccia or intraformational limestone conglomerate. These are widespread in the Mahogany Hills and were recognized as far east as Newark Mountain in the Diamond Moun- tains. Limestone pieces, ranging in length from less than 1 inch to 8 inches, are imbedded in a matrix of virtually the same sediment, but usually having a dif- ferent shade of gray. More than half of the frag- ments are angular, others show some rounding. Commonly the fragments include fossils not found in the matrix, but there is no indication of long transporta- . tion. The mud breccia is not made up of flat pieces that are rather closely spaced like some so-called edge- wise conglomerate. Although slump bedding and evi- dence of flowage were not noted, these deposits are probably a result of oversteepening and undermining by wave and current action along banks of partly con- solidated sediments. Mud breccia of this type is easily confused with cata- clastic breccia of later origin, especially where the rocks are badly deformed; this is true in the outlying pedi- ment outcrops of Devils Gate northwest of Burlington Canyon (loc. 88), where mud breccia and associated limestone beds of the Devils Gate are strongly dis- turbed, possibly in the lower plate of a thrust. Whereas no suggestion of coral reef structure has been detected in the Devils Gate limestone, corals, stro— matoporoids, and other important lime—building or- ganisms are locally abundant. There exist scattered centers of concentrated rugose coral growth, but no moundlike biohermal masses ofcorals and associated lime builders were observed. That these may eventually be found in this area is not improbable. It may also be significant that the mud breccia is commonly in limestone that. contains much colonial and solitary coral material. Nearest approach to biohermal or patch-reef develop- ment is in thick-bedded stromatoporoid and “spaghetti coral” facies of the middle and lower parts of the Devils Gate. These bedded deposits are locally made up largely of slender digitate favositids and stromatopo- roids that include both nodular growths and branch- ing forms of the Amphipom type. No suggestion of steeply inclined flank beds or the moundlike shape of coral-stromatoporoid limestone bodies was detected. The finer organic structure is commonly so poorly pre- served in these limestones that material of surficial stro- matoporoid appearance may be partly algal and best classified as “stroma’tolitic”. Fossil material is frequently silicified in the upper part of the Devils Gate limestone, the shells of corals and brachiopods weathering limonitic brown. The fossil silification pervades the rock and probably took place relatively early, perhaps as a result of diagenetic activity. Where fossils in the upper part of the Devils Gate are unsilicified, as in the Spirifer argentara'us zone, they are characteristically preserved as soft white pearly- shell material that contrasts sharply in color with the enclosing dark-gray limestone. Owing to hardness and brittleness of the rock, these soft fossils, though excel- lently preserved, are removed with the greatest of dif— ficulty. Hence, most of the fossils from these beds available for study are weathered and peeled, lacking surface ornamentation. , STRATIGRAPHY AND FAUNAS The Devils Gate limestone lies between the Nevada formation and the lower part of the Pilot shale of Late Devonian age. The type section is faulted, intruded by igneous rocks and lacks an exposed stratigraphic base. Southward older beds of Devils Gate limestone are ex— posed and the formation rests conformably upon the Nevada north of Modoc Peak (pl. 1). Recent work at Newark Mountain (Nolan, Merriam, and Williams, 1956, p. 48—52) shows the Devils Gate section to ‘be un- broken from bottom to top (fig. 8). Therefore, in describing Upper Devonian strata of the region it is advantageous to consider both sections jointly. Whereas fauna] differences are evident in the formation between Devils Gate and Newark Mountain, the lithology is far more uniform passing laterally from west to east than is that. of the subjacent Nevada formation. A transition zone, ranging from 30 feet to about 7 5 feet in thickness, usually marks the Nevada-Devils Gate boundary. This boundary zone is well shown at Newark Mountain and on the west side of Table Moun- tain in the Mahogany Hills. Within the transition in- terval, dolomite and limestone beds sometimes alternate. Light-gray dolomitic beds and irregular dolomite bodies occur sporadically above the transition zone in the lower third of the formation. 52 PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA .uwdzz .mdoud sawuafl "Ea 35$ onSS=< 23 5 35am szeou :Eczos. 98.. 2_Eo.o_u E3282 2.6.. Ear—8.585 LI 2 05 52:2: ”gees“. x8; coumam A: 00$ .352: 0559.3 5250 9.056 lllllll'll'l|.|||m 9 23 .359: £58 52502 35.5w E 39 .352: 223$ 59880; E 35 ESE. £528 22m in 33 35:88:35 :LQYEW: \\\\\\\\\\\m 2.8 :23 SEE: mcoN gggtum 9 3b Snagfl 2352 2: B can 530.. 5:538 we 322.331: «Md 25395 9:39? Batman. coflflwnuoolfi Huh-arm .3125 a)? :mngo 2am A: 0003 :oszLE «$962 2: 3 tan. 22:5. 22:98 06.22 A: 0an 5:252 mung 9: 8 tag 595 At CONS ocofioE: 3nd m__>wo ocoN 3.23:»5: [53.3.35 383E: Emu m__>an_ 35582:: 9.3 sgsimetév 362 ES 3.5.3.: E 93 22m «BE 9: 3 two 530.. E 28 28.? «BE 2: 3 {ma Luna: \ 08 OF: MEN ..\ a __ 2 ml. 22w :mEEmzo Acoxcmo .285 53:20.2 :5sz w €288 £285 £2522 x5262 m 52:38 3a.. IIII-||||I|| {EHHflalemflérllullHlxl h \\\\\l 297 .25 m5 .0 tan hgazlam EEQBn. :96 no 23x0 223E: Emu «.33 ~52 mzffiguaé subsgm 323E: 23 £33 <3 5555036 3:33 339‘ SEN SE~§§§§W ocoN Léfgio R1: , uwucuoowéz 0:232: 28.. ucn 22m $2520 88 238 e m 297. SE 9: 8 tag 526.. 53:30.2 9.6.. N occfiwE: 23 233 9: 3 tan. Baa: 5:850 33 caaaiflmflz 32522 2%: >v=m> 822.2 a DEVONIAN SYSTEM 53 Topmost Devils Gate limestone grades upward into the basal Pilot shale. At the east entrance to Devils Gate pass, the formational boundary is well shown north of U.S. Highway 50, about 65 feet stratigraphic- ally below the lower porphyry sill. This contact may also be seen in Toll House Canyon (Hayes Canyon) at Newark Mountain. Uppermost layers of the Devils Gate limestone contain an increasing amount of silt and fine siliceous sand introductory to the pinkish, shaly, and arenaceous conodont-beariug limestone beds of the lower part of the Pilot. The Devils Gate formation is on the whole rather monotonous lithologically, and unlike the Nevada for- mation does not lend itself particularly well to conven- ient lithologic subdivision. Two members have been defined locally in the Diamond Mountains (Nolan, Mer- riam, and Williams, 1956, p. 49), where a separation could be made by mapping a thin bed of oolitic lime- stone. ’In the type area and the Mahogany Hills, where the oolitic marker was not recognized, it is possible to distinguish an upper interval about 300 feet thick, in which brachiopods and rugose corals are abundant and diverse and wherein occur the mud breccias and spo— radic dark-gray chert nodules. Pinkish—mottled argil- laceous limestone interbeds with lumpy bedding sur— faces and nodular weathering are characteristic. Below the upper interval, the, lithology and faunas are less di- verse, and the most abundant fossils are stromatopo- roids and Uladopom. 7 In the Mahogany Hills the Devils Gate limestone lends itself to a fourfold paleontologic zonation as fol- lows in stratigraphic order: 4. Cyrtoapim'fer zone 3. Pachyphyllum zone 2. Spim'fer argentarizus zone 1. stromatoporoid zone The twO upper faunal zones occupy the upper 300-foot lithologic division, and the Spirifer argentam'us zone extends upward from the lower monotonous and thicker lithologic division into thevupper division. Thick beds of stromatoporoids and slender branching favositids of the Uladopom type characterize the stromatoporoid zone. The “spaghetti limestone” formed largely by favositids includes also the branch- ing stromatoporoid Amphipom. Nests of Atrypa are fairly abundant, but other brachiopods are sparsely rep- resented. In the southern Diamond Mountains, corals of the genera Temnophyllum, Disphyllum, and Tham- nopm'a. were collected in the lower 200 feet of this zone. F aunas of the. Spirifer argentam'us zone range through about 500 feet of the middle part of the Devils Gate. Fossils are numerically abundant in some beds, although the number of species is small. Most common are Spirifer argentam'us, Airy/pa montanenszls, and A. devoniana; less common is Tenticospz'm’fer utahemz's. H ypothym'dina appears low in the zone with the small H ypothym'dim sp. a. Among the corals only the genus Mictophyllum has been identified. Large spirifers with the external features of S. argen- tam’us occur locally in the middle part of the Devils Gate. Spirifer argentarius is ordinarily a small form. The larger spirifers also resemble S. mymondi Haynes and may be confused with the much older “S.” ping/o— nensis of the Nevada format-ion. Within the lower range of Spirifer argentam'us are localized molluscan facies with abundant Orecopz'a mccoyi (Walcott), a distinctive gastropod (Knight, 1945). In this association is the small Spiriferengel- martini, differing at least subspecifically frOm S. urgen- tam’us in its high cardinal area and narrower shell. In the Newark Mountain and Alhambra Hills areas, there occurs in abundance below beds with S. argentarim a small crytinoid brachiopod with external appearance of the genus Tylothyrz's North, or E osyringothym‘s Stainbrook (1943, p. 431, 438). Provisionally called T ylothg/ris sp. a this distinctive form probably occurs in the lower range of S. argentam'us. A significant faunal discontinuity separates the Pachyphyllum zone from the underlying Spim'fer ar- gentam'us zone. In the Pachyphyllwm zone, rugose corals are abundant and diverse; such forms are scarce below and are virtually absent in the overlying Ogrto- > spim'fer zone. Characteristic are species of Pachyphyl- lum and Phillipsastmea, the large solitary Chomphyl- lum infundibulum (Meek), and Macgeea. Common also is Syringopom. In contrast, brachiopods are scarce in the Pachyphg/Zlum zone of this particular area, though the important key fossil Hypothym'dina em- monsz' (Hall and Whitfield) occurs with Pachyphyllum northeast of Modoc Peak. An incomplete ammonoid from the upper part of the Devils Gate was identified as Manticocems cf. Ill. sinuosum (Hall) by N. J. Silberling of the U .S. Geolog- ical Survey. It occurred as float below the Pachyphg/l- Zum zone north of Devils Gate and may have come either from that zone or from the Oyrtospim'fer zone above. Manticocems sinuos'wm is an Upper Devonian species in New York State (Miller, 1938, p. 115), where it is reported in the Genesee, Naples, Chemung, and Canadaway formations. Faunas of the Uyrtospz'rifer zone are fairly large, di- verse, and manifest a complete change from those of the underlying zones. Corals are commonly lacking, the fauna consisting mainly of brachiopods. Absence of Atrypa is significant, especially when its abundance in the middle and lower parts of the Devils Gate is con- 54: PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA sidered. Characteristic fossils are: Cyrtospz'm'fer por- tae Merriam, Nudi’rostm walcottz' (Merriam), Athym's angelicoz'des Merriam, Schizophom'a simpsoni Merriam, and Productella. FACIES LOCALIZATION 0F FAUNAS A comparison of Devils Gate faunas and stratigraphy of the Mahogany Hills with those of the Diamond Mountains and more distant areas reveals a geographic spottiness of faunal occurrence (fig. 8). The discon- tinuity suggests control by local environmental condi- tions. A case in point is seeming absence of the 03/7750— spz'rifer faunas from the Newark Mountain section, which otherwise appears to be complete depositionally. Physical evidence of nondeposition or erosion of upper beds normally including this zone was not observed. Similarly the Uyrtospz'm‘fer faunas seem to be unde- veloped in the White Pine district, where the Deirils Gate formation is otherwise well represented. Approximate position of the Pachyphyllum zone at Newark Mountain is indicated by a single float speci- men of this coral collected in 1938. Evidently the co- lonial rugose corals are extremely scarce in the Newark Mountain-Alhambra Hills belt, where the interval in question is occupied by a predominantly brachiopod facies characterized by Martinia neeadense's (Walcott). Use of the generic name Martinia should be qualified by saying that, like earlier members of this form group in the Nevada formation, the Devils Gate species is prob- ably neither true M artim'a or Martiniopsis. Further comparison may show that ”evade/1132's is correctly placed in Warrenella (Crickmay, 1953, p. 596). Associated with M. nevadensis are species of Schizo- phom'a. Dalmamlla, Pugnoz'des, Atrypa of the A. de- vonioma Webster type, and scattered corals assigned to Macgeea, T abulophyllum, Disphyllum, and T hamm- pom. Locally Schizophom'a is the most abundant fossil. Conversely, Martinia mvadensis was not found dur— ing this study in the Pachyphyllum zone of the Devils Gate type area. However, the type specimen is reported by Walcott to have been collected 41/2 miles south of Devils Gate. At Newark Mountain (fig. 8) beds of the Martinia macadamia facies, or probable Pachyhyllwm, zone equiv- alent, are overlain by the limy, arenaceous conodont beds of the lower part of the Pilot shale. At Devils Gate equivalent conodont beds rest upon strata of the Oyrtospz'm'fer zone. Fossil collecting in Upper Devonian beds of the cen- tral Great Basin reveals five separate loci where the Pachyphyllum and Phillipsastmea coral facies is well developed. These are: (1) Devils Gate vicinity; (2) Mahogany Hills, 2 miles south of Hay Ranch (10c. 81) ; (3) Belmont Mill in McEllen Canyon, White Pine dis- trict; (4) Treasure Peak, \Vhite Pine district; and (5) the northern part of an unnamed range, 31/; miles southwest of Monte Cristo (Green Springs quadrangle), Nev. (See fig. 2.) The gastropod facies with abundant Orecopia is very much localized and is usually limited to relatively pure clean limestone. In this facies the beds are sometimes loaded with Orccopia accompanied by very few other forms. Locally these Orecopia beds have been dolomi- tized, as in outlying hills at the east foot of Newark Mountain. THICKNESS Where the base is unexposed at Devils Gate, the Devils Gate limestone is about 1,100 feet thick. An esti- mate of 1,800 feet made earlier at Modoc Peak, where the Devils Gate rests on the Nevada, proves unreliable because of faulting. At Newark Mountain the relai tively unbroken Devils Gate section is about 1,200 feet thick, agreeing with Sharp’s (1942, p. 664) measure- ment of 1,200 feet in the southern Ruby Mountains, AGE AND CORRMTION The Devils Gate limestone includes deposits of Late Devonian and probable late Middle Devonian age. It rests with gradational boundary on upper dolomite of the Nevada bearing Stringocephahw, an indicator of the Givetian stage, late Middle Devonian in Europe. The stromatoporoid zone in the lower beds of the Devils Gate, though yielding no distinctive Middle Devonian indicators, seems to lack fossils that would place them conclusively in the Late Devonian. The coral Temno- phyllum in the lower 200 feet suggests Middle Devonian. Merriam (1940, p. 9) initially regarded the Spirifer argentam'us zone as of late Middle Devonian age; how— ever, in recent years these beds have come to be classed by most Devonian authorities as Frasnian Late Devo- nian. It is nonetheless recognized in~the central Great Basin that an abrupt faunal discontinuity exists between beds of the S. argentam'us zone and those of the Pachgphyllum zone. Above this discontinuity appear, genera of acknowledged Frasnian Late Dovonian age, among which are Pachyphyllurm. and the ammonoid Manticocems. Hypothym'dina emmomi of the Patchy- phyllum zone may also relate these beds to the Inde- pendence shale of Iowa (Stainbrook, 1945, p. 3, 42—43) and to the Frasnian of Europe. This distinctive brach- iopod also resembles H. venustula of the New York Tully limestone, but associated faunas provide little support for close alinement, as those of the Tully are seemingly older, if not actually Middle Devonian. DEVONIAN SYSTEM ' 55 The Uyrtosp/irifér zone with Cyrtospirifer and Athy- m's angeliooz'des is clearly of Late Devonian age, in the range from Frasnian to Famennian of Europe (Mer- riam, 1940, p. 59—61; Cooper and others, 1942, p. 1756). ‘ Since the initial Devils Gate studies, much informa— tion has accumulated on distribution and correlation of its faunas Within the Great Basin. Upper Devils Gate faunas have been recognized at scattered localities as far east as the Thomas Range, Utah, and south to Yucca Flat, Nev., and west to the Death Valley—Inyo region of California. Detailed stratigraphic studies of Devils Gate equivalents have been made for the US. Geological Survey by M. H. Staatz in the Thomas Range and by R. K. Hose in the Confusion Range in Utah ; by Johnson and Hibbard (1957) in the Yucca Flat area of southern Nevada; and by McAllister (1952) and Merriam in the Ubehebe and Inyo areas of southeastern California. In the Thomas Range Pachyphyllum beds persist through a remarkably great thickness of limestone and are overlain by beds with Cyrtospim’fer. In the Con- fusion Range, as demonstrated by Hose, beds of middle Devils Gate age are characterized by Tenticospirifer utahensis seemingly unaccompanied by SMm'fer argen— taréua. At a lower horizon Tylothym’s sp. a is abundant in a zone that seems to agree stratigraphically with 00‘- currence of this form at Newark Mountain. The upper Lost Burro formation (McAllister, 1952, p. 19) of the Ubehebe and Inyo Mountains in California carries Cyrtospirifer and gastropods questionably referred to Orecopia mccoyi. LoWer beds of the Lost Burro yield Stringocephalus and are of Middle Devonian age. With most of the Great Basin occurrences the Cyrto- spim'fer zone is distinguishable from the Sph’ifer argen— tam'us zone. In the lower range of S. argenmrius the gastropod Orecop-z'a. mocoyz' (Walcott) is an especially useful indicator (Knight, 1945, p. 586), having been found at widely separated localities in the upper Guil- mette of Gold Hill, Utah (Nolan, 1935, p. 21), the Valentine member of the Sultan limestone at Good- springs, Nev. (Hewett, 1931, p. 16), and the Devils Gate equivalent at Yucca Flat, Nev. (Johnson and Hibbard, 1957). Beyond the Great Basin, but within the Cordilleran belt, are many recorded occurrences of Late Devonian stata equivalent in age to some part of the higher Devils Gate limestone. , To the north some of these less distant strata are classed as Three Forks formation and to the south as Martin limestone (Merriam, 1940; Cooper and others, 1942). In Arizona the Martin carries Uyrtospz'rifer faunas and Pachyphyllwm; the so- called “Jerome formation” bears Pachyphyllmn (Stoy- anow, 1936, p. 498). The Sly Gap formation of New Mexico yields Oyrtospz'm'fer, Pachyphylhtm, Macgeea, and Hypothyridina cf. H. any/nomad (Stevenson, 1945, p. 239; Stainbrook, 1948, p. 765—790). Largely under impulse of petroleum exploration, significant advances have recently been made in knowl— edge of Late Devonian rocks from Montana north to the Mackenzie Valley of Canada. Although fauna] similarities to Great Basin Late Devonian have long been recognized, only recently has it. become possible to evaluate these objectively, as the northern Cordil- leran fossils become more fully described. C’yrtospirifer and related brachiopods show an excep- tional degree of morphologic and phylogenetic differ- entiation in western Canada (Crickmay, 1952, p. 585—609) comparable to that in the southern Shell Creek Range, Nev. (Merriam, 1940, p. 39—40). As shown by McLaren (1954, p. 159—181), rhynchonellids of the genera Nudirostm and Pugnoz'des are diverse in Can- ada, and have detailed zonal value. These genera appear abruptly and abundantly above the Spim'fer argentarius zone in the Great Basin. Of the Great Basin species Nudirostm walcotfi, of the upper part of the Devils Gate, is cited by McLaren as characteriz- ing the Alexo formation, Where it occurs with Cyrto- spirz'fer. C’yrtospim'fer persists through the overlying Palliser beds. Strata of the PachyphylhI/m. or Martinia nevademis zone are identifiable in western Canada (Warren, 1942, p. 133). In the Canadian Rockies (McLaren, 1954, p. 160) these are represented by the Perdrix with Martinia cf. M. nevadensz's and the overlying Mount Hawk with H ypothym'dina cf. H. emmonsi. ‘ The Spirifer argentam'us fauna is reported from sev- eral localities in the region extending northward from Montana (Laird, 1947, p. 453—459) to Canada. Repre- sentative is the Flume formation of the Canadian Rockies, with Spim'fe'r jasperemis and Spirifér cf. S. engelmomm‘. Though detailed comparison is needed, it seems likely that jasperenvsis is a synonym of argentarius. Spirifer engelmtmm', or similar forms, have been identified in other northern areas of Montana (Laird, 1947, p. 453) and western Canada (\Varren, 1942, p. 130; McLaren, 1954, p. 160), where Tenticospirifer utahensz‘s of the argentari’us zone is also represented. Late Devonian beds assigned to the Waterways and Hay River formations, in the territory stretching from Great Slave Lake along the upper Mackenzie Valley, ‘ are correlative with the Devils Gate of the Great Basin (Warren, 1944, p. 106—107; Warren and Stelck, 1949, p. 146—147; McLaren, 1954, p. 169). The Hay River limestone contains Oyrtospz'rifer and Nudirostm wal— cotti, whereas the Hay River shale beds (Warren, 1944, 56 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA p. 112—113) have yielded Hypothym'dina, cf. H. emmonsz'. ‘ Corals from the upper Mackenzie basin (Smith, 1945) Show obvious relationship to upper Devils Gate species. Among these are members of the Pachyphyl- Zwm, Phillipsastmca, Tabulophyllum, and Macgeea groups. STRATA 0F LATE DEVONIAN AND EARLY MISSISSIPPIAN AGE PILOT SEALE Lowest beds of the “White Pine shale” defined by Hague (1892, p. 68) are seemingly equivalent to the Pilot shale of the Ely area, Nevada (Spencer, 1917, p. 26). In the Diamond Mountains northeast of Eureka (Nolan, Merriam, and Williams, 1956, p. 52—53) more than 300 feet of Pilot is represented. The lower part of these shale beds contains Late Devonian conodonts. The upper part, which has yielded no fossils in the Eureka area, is probably of Early Mississippian age on the basis of fossil evidence from other districts. Ac- cordingly, the Pilot is classed as Late Devonian and Early Mississippian. Only the lower part of the Pilot of Devonian age was identified in the Antelope Valley area. ‘ LOWER PART OF THE PILOT SHALE GENERAL FEATURES Of Late Devonian age, the lower part of the Pilot shale rests conformably on Devils Gate limestone at Devils Gate. These relations are well shown on the north side of US. Highway 50, at the east entrance to the pass; here the lower part of the Pilot, about 75 feet thick, is gradational With Cyrtospirifer-bearing Devils Gate and is separated from stratigraphically higher black shale by an alaskite porphyry sill. The lower part of the Pilot consists of fine silty to sandy cal? careous shale and platy arenaceous limestone. [Medium to dark gray in color when fresh, these rocks weather light gray with pinkish surface stain. Silt-size quartz granules are numerous, together with dark—brown phosphatic particles, many of which are fragmentary conodonts. These strata are similar lithologically to the lower part of Pilot of the more continuous expo- sures at Newark Mountain (Nolan, Merriam, and VVil- liams, 1956, p. 53). Higher black shale beds above the porphyry sill remain undated paleontologically but are provisionally regarded as Chainman shale rather than the upper part of the Pilot on the basis of lithology. AGE AND CORRELATION In the Eureka district the conodont—bearing Pilot shale (Nolan, Merriam, and Williams, 1956, p. 53) may bridge the gap between latest Devonian and earliest Mis- sissippian. The late W. H. Hass of the US. Geological Survey examined conodonts from the Devils Gate 10- cality and lists the following genera: Himleodclla sp. Icriodus sp. Palmtolepis spp. (common) Polygnathus spp. numerous fragments conodonts of bladelike, barlike, and platelike Hass reported as follows concerning age of this faunule: L It is my opinion that this collection comes from beds of Late Devonian age because of its stratigraphic position and because it contains specimens of Icm‘odus and Palmatolepis. I believe that the stratigraphic range of these two genera is Middle to Upper Devonian; however, some stratigraphers are of the opinion that these two genera range naturally into the lower part of the Mississippian. No detailed comparison has yet been made with the better preserved and doubtless equivalent lower Pilot conodont assemblages from Newark Mountain. Collec- tions from Newark Mountain also studied by Hass like- wise are from pinkish platy arenaceous limestone. In addition to genera listed above from the occurrence at Devils Gate, the Newark Mountain assemblages include Aqurodella cf. A. curvata Branson and Mehl, Bryan- todus, Hibbardella, Ligonodma, and Priom'odus. The upper part of the Pilot shale has not yielded fossils at Newark Mountain, but the discontinuous Joana lime- stone, which here and there overlies it, is of Early Mississippian (Madison) age. UPPER PALEOZOIC ROCKS GENERAL FEATURES Mississippian and Permian rocks are present in the vicinity of Antelope Valley, but the two systems are not superposed and occupy widely separated outcrop belts. No Pennsylvanian strata were recognized. To the east in the neighboring Diamond Mountains and Eureka district, the higher Paleozoic section is more nearly complete, with Mississippian, Pennsylvanian, and Permian rocks in continuous depositional order. Siliceous clastic rocks of Mississippian age resem- bling closely those of the Diamond Mountains occur in the northern Mahogany Hills; these strata were not found in the Monitor Range on the west side of An- telope Valley. The Mississippian elastic rocks in the Mahogany Hills are the youngest Paleozoic strata ex— posed and are overridden directly by the upper plate Ordovician Vinini formation. There is no indication that Pennsylvanian or younger strata of the Diamond Mountains were deposited in that area. Although knowledge of areal geology is not ade- quate in these latitudes, the Mahogany Hills belt may UPPER PALEOZOIC ROCKS 57 approximate the western limit of Carboniferous de- position in the Great Basin. To the west, only Per- mian strata are known with assurance in the upper Paleozoic column. Black shale beds intruded by gran- itoid rocks near Austin, Nev., in the Toiyabe Range have previously been assigned to the Carboniferous (Em- mons, 1870). Lithologically these shale beds are more suggestive of Ordovician Vinini than Carboniferous, but only fossil evidence will eliminate possibility of Carboniferous age. Emergence and erosion were tak— ing place during Pennsylvanian time in the Eureka district, as shown by lateral discontinuity and local ab- sence, of the Pennsylvanian Ely limestone. Whether nondeposition and erosion were responsible for complete absence of Carboniferous from the Mahogany Hills westward cannot at present be fully demonstrated. Rocks of the Permian system occur in the west, where Carboniferous strata are lacking. They are exposed on the flanks of Lone Mountain, in the northern Monitor Range, and at scattered localities farther west in the Great Basin. Permian rocks of Antelope Valley and the western Great Basin are usually associated with graptolite-bearing Ordovician deposits. MISSISSIPIAN ROCKS In the Mahogany Hills and at Devils Gate the rocks of Mississippian age agree rather closely with the middle and upper parts of this system, as exposed in the Diamond Mountains and in the vicinity of Eureka; in those areas the Mississippian includes the following formations in stratigraphic order: Diamond Peak for- mation, Chainman shale, Joana limestone, and upper part of the Pilot shale. However, in the area under consideration the lower units, Joana limestone and the upper part of the Pilot shale, were not recognized. . Moreover, separation of Chainman from Diamond Peak was not practicable through the Mahogany Hills. Use of these terms follows revision of Carboniferous stratigraphy in the Eureka district (Nolan, Merriam, and Williams, 1956, p. 52—63), where Pilot, Joana, Chainman, and Diamond Peak are regarded as separ- ate formations, and the controversial name “White Pine shale” is avoided (Merriam, 1940, p. 45). CHAINMAN SHALE AND DIAMOND PEAK FORMATION, UNDIFFEREN’I‘IATED AREAL DISTRIBUTION The Chainman and Diamond Peak formations, un- differentiated, are' well exposed at Devils Gate and southward along the east side of Yahoo Canyon for 4 miles. Small erosion-remnant outcrops occur on the lower north and west flanks of the Mahogany Hills. Just south of Devils Gate pass, the eastward-dipping shale and sandstone of this section rest on the lower part of the Pilot shale of Late Devonian age and are overthrust on the east by Ordovician chert and shale of the Vinini formation. North of US. Highway 50, near the east entrance to Devils Gate pass, the lower black shale beds may be observed to advantage between two alaskite porphyry sills. A lower sill separates these beds from the conodont-bearing upper Devonian beds of the Pilot. The upper part of the Pilot and the Joana limestone of Early Mississippian (Madison) age are not present, but would normally be expected at about the position of the lower sill. Alaskite sills and dikes of this type, as much as 50 feet thick, are common in the Chainman and Diamond Peak sequence south of Devils Gate. ‘ LITHOLOGY AND STRATIGRAPHY In the Devils Gate area, the lower part of the Chain- man and Diamond Peak section is largely black car- bonaceous shale, whereas the upper part is prevailingly gritty sandstone with shale intercalations and scat- tered beds of fine conglomerate. No limestone beds were recognized. In general, the character and verti— cal distribution of these strata are in agreement with the combined Chainman shale and Diamond Peak for- mation of the Diamond Mountains and Eureka district. As seen on the north side of Devils Gate pass, the lower beds of this sequence are black noncalcareous somewhat silty clay shale. They are fairly smooth, with pencil structure in some places, and lack black interbeds of chert like those of the upper part of the Pilot shale in the Diamond Mountains. Although the upper part of the Pilot would be expected at this stratigraphic position, the shale beds in question re- semble normal Chainman more closely. Lack of bedded chert also distinguishes the black shale from the Vinini, which tends to weather light gray or white and breaks down to thin flat plates and flakes. Pencil structure is generally not a feature of the Vinini nor is white weathering a characteristic of the Mississippian black shale. Poorly sorted sandstone that weathers brown, and fine conglomerate of the Chainman and Diamond Peak sequence consist mainly of chert fragments, many of which are angular. Well-rounded quartz granules are present in smaller amounts. The chert varies in color from light gray to black, and some is greenish. Darker gray fragments of chert predominate and ii— monitic matter is fairly abundant in cavities and inter- stices. These dark-colored gritty clastic rocks con— trast sharply with the clean well-sorted light-gray quartz sand and orthoquartzi‘te that characterize the 58 PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA normal eastern sequence of Ordovician, Silurian, and Devonian formations in this region. The dark Missis— sippian chert-rich elastic rocks are, however, distin- guished with considerable difficulty from those of the overthrust Vinini Ordovician. In fact, both were mapped together as “Diamond Peak quartzite by the Hague party. Like the brown Mississippian sand- stones, some of those in the Vinini contain abundant angular gray chert fragments. Whereas the Mississip- pian sandstone beds commonly show a somewhat greater proportion of very dark chert and less argil- laceous matter than those of the Vinini, it is doubtful that the two can be distinguished readily by gross litho- logic features. Furthermore, both contain poorly pre— served plant and plantlike matter. With the Vinini this material is probably in part algal and in part graptolitic. Significant problems of stratigraphy in this area per— tain to apparent absence of the lowermost Mississippian units and to means of distinguishing Mississippian elastic rocks from similar rocks of the Ordovician Vinini formation. Late Devonian conodont-bearing strata of the lower part of the Pilot are present here, but the upper part of the Pilot and Joana limestone are unrecognized, sug— gesting local disconformity beneath the Chainman and Diamond Peak sequence. However, no physical evi— dence of stratigraphic break was observed, and marine deposition appears to have continued through the Devils Gate limestone interval into that of black shale assigned to the Chainman and Diamond Peak succes- sion. Evidence of disconformity is more convincing on the west side of the Mahogany Hills (pl. 1), where coarse chert-rich brown sandstone like that of the Diamond Peak rests directly upon the Devonian Devils Gate limestone. The basal sandstone contains reworked angular blocks of Devils Gate limestone. Fossil evi- dence is insufficient to determine whether or not the sandstone actually represents the upper or Diamond Peak part of the Mississippian column. Relationship of lower plate Mississippian to upper plate Vinini Ordovician is especially confusing where brown sandstone of the one is either in contact with or in close proximity to that of the other. Such relation- ships are noted along Yahoo Canyon. Less difficulty was experienced in mapping the thrust boundary just south of the east entrance to Devils Gate pass, where . overt-hrust Vinini is in considerable part bedded chert. The same eastern thrust segment continues north be- yond Devils Gate pass and may be observed at Anchor Peak, where lower plate standstones of the Chainman and Diamond Peak contain land plants. Fossils, other than fragmentary plant remains, are extremely scarce in the Chainman and Diamond Peak of the Mahogany Hills. Limestone interbeds, which elsewhere yield marine fossils in this part of the section, were not discovered in the area under consideration. Only unidentifiable brachiopod impressions were found in the coarse basal sand on the west side of the Mahog- any Hills, and conodont impressions occur in the lower black shale at Devils Gate pass. PERMIAN SYSTEM GARDEN VALLEY FORMATION OCCURRENCE AND NAME The Garden Valley formation of Permian age under- lies the northern half of the Twin Spring Hills (pl. 1), a northeast terminal salient of the Monitor Range. These Permian strata are lithologically and faunally similar to the Garden Valley formation of the type area (Nolan, Merriam, and \Villiams, 1956, p. 67), 25 miles northeast of the Twin Spring Hills. Beds of the Garden Valley have not been recognized elsewhere in the area under consideration, but are exposed on pedi- ment slopes of Lone Mountain, halfway between the Twin Spring Hills and the type Garden Valley outcrop. On the south the Garden Valley strata of the Twin Spring Hills (Ice. 82) are in contact with and probably rest unconformably upon Ordovician graptolitic de- posits of the Vinini formation. On the north they are overlain unconformably by sandstone and shale assigned to the Newark Canyon formation of Cretaceous age (10c. 91). The Garden Valley Permian rocks, everywhere as- sociated with the graptolitic beds of the Vinini are provisionally regarded as a western facies introduced by thrust movement, together with the Vinini. LITHOLOGY AND STRATIGRAPHY In the Twin Spring Hills, the Garden Valley strata consist of arenaeeous and pebbly limestone, siltstone, sandstone, chert pebble conglomerate, and limestone cobble conglomerate. Limestone cobble conglomerate and arenaceous limestone are the most abundant. Mapping of the Garden Valley-Vinini contact in the Twin Spring Hills suggests that it is probably an un- conformity. Such a relationship has been demon- Strated at Tyrone Gap (fig. 2) in the type area of the formation, where angular chert fragments of the Vinini were reworked depositionally in basal beds of the Per- mian unit. Reworked Vinini fragments were not ob— served in lower beds of this Permian sequence in the Twin Spring Hills. UPPER PALEOZOIC ROCKS . 7 59 Coarse, gritty brown and reddish-brown sandstone beds rest upon the limestone cobble conglomerate at the north end of the Twin Spring Hills. With these are silty shale and fine-grained sandstones that weather olive tan to dusky yellow. The coarse-grained sand- stone consists largely of gray chert grains, many of which are angular. Distribution of these beds suggests that they overlap unconformably upon the limestone cobble conglomerate, though no angular discordance was recognized. Absence of fossils in the upper sand unit prevents determination of age, but these beds re- semble the Lower Cretaceous Newark Canyon forma- tion of the Diamond Mountains and the Eureka mining district (Nolan, Merriam, and Williams, 1956, p. 68). Two principal stratigraphic subdivisions are de- finable in the Garden Valley formation of the Twin Spring Hills: a lower unit, about 500 feet thick, com- posed largely \of medium-gray rather thick-bedded sandy to pebbly limestone, and an upper unit, approxi- mately 4,500 feet‘ thick, composed of limestone cobble conglomerate. Between these two major divisions there occurs a thin reddish and buff sandstone, siltstone, and shale unit. The lower 500-foot limestone unit is clearly of marine origin, whereas the overlying reddish unit Suggests emergent conditions that may well have per— sisted into the interval of limestone cobble conglomer— ate, which yielded only reworked fossils. The lower part of the lower 500—foot carbonate unit includes buff and pink platy-weathering fine—grained silty beds of limestone. Like contiguous red-stained shale of the Vinini, these Permian beds may have re- ceived their pinkish coloration by leaching of ferru- ginous matter from lavas which, prior to erosion, probably covered this area. Most of the lower 500-foot unit is thick-bedded; crossbedding is well shown where siliceous sand grains weather in relief. Bands of lime- stone with very coarse sand grains and lenses of chert pebble conglomerate are also present. This chert was probably derived from the underlying Vinini. Silicified fossils occur in the lower platy pinkish lime- stone, whereas just above this zone lies a coral bed con- taining numerous large colonial corals. Fine—grained fairly-pure limestone beds of medium-gray color near the middle of the loWer 500-foot unit contain pro- ductids, and have yielded a fauna of small silicified brachiopods. Limestone conglomerate makes up nine-tenths of the Garden Valley formation as exposed in this area. It is composed of subrounded to angularfragments of light-gray and medium-gray limestone ranging in di- ameter from less than 1 inch to 10 inches. Cement is calcareous matter mixed with fine sand of light gray to pinkish color. Scattered angular fragments of gray and greenish-gray chert are present and were possibly derived from Ordovician bedded chert of the Vinini. The conglomerate tends on the whole to weather fairly light gray with patches of pinkish, yellowish, and buff color. THICKNESS The Garden Valley formation/is estimated to be more than 5,000 feet thick in the Twin Spring Hills. Of this succession, the lower marine Lower Permian division is about 500 feet thick, the overlying limestone conglom- erate about 4,500 feet thick. AGE AND CORRELATION Only the lower 500-foot arenaceous limestone is dated paleontologically, the upper limestone con- glomerate having yielded no contemporaneous fossils. Early Permian (Wolfcamp) fossils are common in the lower 250 feet of the formation near the Garden Valley- Vinini contact. Three fossil zones are recognized: A lower brachiopod zone with a silicified brachiopod vas- semblage; a middle colonial coral bed; and an upper zone with productids. Protracted search for fusulinids in Garden Valley strata of the Twin Spring Hills was unsuccessful. Fusulinids are present in the type Gar- den Valley and in this formation at Lone Mountain. In the type Garden Valley, the lower sandy limestone unit contains Schwagerim near the base, with Pseudo- sohwagem’na and Pamfusulina. higher in this division. ' At Lone Mountain only Schwagerina has been identi- fied. ' In the TwinSpring Hills the lower brachiopod fauna includes the following : Crenispirifer n. sp. H ustedia cf. H. mormoni (Maroon) Dielasma sp. ?0rum’thy_m‘s sp. The common form in the coral bed is a large bushy colonial tetracoral provisionally assigned to Pseudo- zaphrentoides, associated with which is a Syringopora possessing unusually thick tubes. The upper or productid zone, which lies near the middle of the 500-foot arenaceous limestone unit, is characterized by a medium-sized Bumtonia, small rhyn— chonellids, and other small silicified brachiopods. Detailed comparisons with faunas of the type Garden Valley and the Carbon Ridge formation at Eureka (Nolan, Merriam, and Williams, 1956, p. 64—68) have not yet been made. The bushy colonial coral Pseudo— zaphrentm’des is similar to that occurring in the upper 60 PALEOZOIC ROCKS 0F ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA part of the Carbon Ridge formation near the mouth of Secret Canyon in the Eureka district. Comparable species of Dielaema and 20mrithyris occur in the lower brachiopod fauna of the Twin Spring Hills and in the basal Garden Valley of the type area. Spiriferinids occur in both; the Twin Spring Hills forms are assigned to Urenispirifer Stehli (1954, p. 347), whereas those of the type Garden Valley appear more closely related to Spiriferellimz newelli Stehli. Lithologic comparison of the Permian section in the Twin Spring Hills with the type Garden Valley reveals significant resemblances as well as some differences. Thus both columns have a lower fossil-bearing arenace- ous limestone division, about 500 feet thick, each over- lain by thick unfossiliferOus conglomerate. In the type area a disconformity separates the lower arenaeeous limestone from the overlying conglomerate. Whereas this unconformity was not recognized in the Twin Spring Hills, its position may be indicated by the red— dish intermediate sand and shale member. The two columns differ in that limestone conglomerate predomi- nates in the Twin Spring Hills, whereas siliceous con— glomerate prevails in the typical Garden Valley, with limestone conglomerate appearing only in the upper part of this division. In places, the Twin Spring Hills conglomerate ‘beds contain large amounts of angular chert fragments, although the cement is calcareous. Derivation of the limestone cobbles is of interest, for many contain Pogonip Ordovician fossils. Among these is the large gastropod Pallisem'a, a characteristic fossil of the Antelope Valley limestone. Certain of the light gray limestone cobbles have the character of Good- win limestone of Early Ordovician age. It is assumed that such materials did not undergo prolonged trans- portation by water. Lack of contemporaneous fossil evidence in the thick upper limestone conglomerate of the Twin Spring Hills suggests that possibly all beds above the. intermediate reddish sandstone may be post—Paleozoic and possibly nonmarine. The limestone conglomerate is evidently post-Wolfcamp Permian and almost certainly pre- Cretaceous. Accordingly, it may be Late Permian or as young as Jurassic. Cobbles, some containing fossils, were derived from Ordovician limestones of the Pogo- nip like those of the normal Antelope Valley sequence. This evidence may be interpreted as conflicting with the theory of thrust introduction of younger rocks, as part of a western sequence. It is conceivable that the post-Wolfcamp conglomerates, if locally derived, may be considerably younger than the thrusting. If, how- ever, they have been introduced by thrusting, it is possible that rocks of the normal Antelope Valley Ordovician carbonate sequence may extend farther west than heretofore suspected. Geologic mapping in the Toquima‘ and Toiyabe Ranges (fig. 2) may yield information on the western extension of Garden Valley rocks and elucidate their origin. Emmons (1870, p. 323, 335) and Hill (1915, .p. 116) report fusulinids and the coral Syringopom at Santa Fe Canyon in the northern Toiyabe Range (fig. 2). Slates and shales of Vinini Ordovician type occur— ring in that vicinity recall the widespread association of Garden Valley Permian with the Vinini graptolitic deposits. Carbonate rocks of possible Garden Valley age are likewise associated with graptolite-bearing Ordovician rocks in the Toquima Range (Marshall Kay, oral communication, 1959). LOCALITY REGISTER Fossil localities and exposures revealing significant stratigraphic and structural features in the Paleozoic rocks of Antelope Valley are given below. Locality numbers are plotted on the geologic reconnaissance maps (pls. 1 and 2). Southern half Antelope Valley area (pl. 2) 1. Monitor Range on west side of Copenhagen (Canyon, 5% miles north of Martin Ranch: Antelope Valley limestone with Maclurites and Giroanella in upper plate of thrust. 2. Monitor Range in saddle on Martin Ridge, 31/; miles north of Martin Ranch: Copenhagen formation, abundant fossils. 3. Monitor Range on west side of Copenhagen Canyon and on north side of Whiterock Canyon: Outlier of Pogonip group on Lower Devonian Rabbit Hill limestone. 8. Monitor Range on east of summit 7702 Martin Ridge, 4% miles north of Martin Ranch: Hanson Creek formation with graptolites. 9. Monitor Range on top of Martin Ridge, 2 miles southeast of Martin Ranch: Hanson Creek formation with graptolites. 10. Monitor Range in Copenhagen Canyon on west side of Martin Ridge, 2 miles north of Martin Ranch and 1 mile southeast of junction Ryegrass Canyon and Copenhagen Canyon: Copenhagen formation with abundant fossils. 13. Monitor Range in narrows of Whiteer Canyon, 11/2 miles northwest of Rabbit Hill: Ninemile formation and Ante- lope Valley limestone with abundant fossils, especially in Orthidiella zone. Didymograptus in shales of the Nine— mile. Overthrust Vinini graptolitic shale and chert across canyon west of locality 13. 27. Monitor Range at east foot of Martin Ridge near north end : Antelope Valley limestone with abundant Palliseria. 49. Monitor Range at northern tip of Martin Ridge: Goodwin limestone with Kainella. 51. Monitor Range at Rabbit Hill: Type section of Rabbit Hill limestone, with abundant ‘silicifled fossils. 52. Monitor Range, 1174 miles north of Rabbit Hill: Abundant fossils in Rabbit Hill limestone. 53. 61. 71. 73. 74. REFERENCES CITED Southern half Antelope Valley area (pl. 2)-—Continued Monitor Range in hill 1 mile north-northeast of Rabbit Hill: Limestone of the Hanson Creek formation overlain by platy limestone of the Roberts Mountains formation with M onograptns. .Antelope Range on east side of Ninemile Canyon near mouth: Oaryocarls shale. . Antelope Range on east side of Ninemile Canyon in saddle on northwest spur of range at measured section: Type section of Ninemile formation with abundant fossils. . Antelope Range on crest of northern tip at altitude 7,500 feet: Nevada formation, Martinia kirki beds with Recep- taoalltes. . Antelope Range on west side of Ninemile Canyon: Shaly Ninemile formatibn with Klrkella; near base overlying Antelope Valley limestone. . Antelope Range, 21/2 miles north-northeast of Blair Ranch ( “Segura Ranch”) : Copenhagen formation with abundant fossils. . Antelope Range, 2 miles north-northeast of Blair Ranch (“Segura Ranch”): Copenhagen formation with fossils. Antelope Range, 2174 miles northeast of Blair Ranch (“Se- gura Ranch”) : Hanson Creek formation with graptolites. . Antelope Range, 4 miles north-northeast of Blair Ranch (“Segura Ranch”) : Beds of Hanson Creek formation with graptolites resting on Eureka quartzite. . Antelope Range, 4 miles northeast of Blair Ranch ( "'Segura Ranch”) : Ninemile formation with fossils. . Antelope Range, 5% miles north-northeast of Blair Ranch (“Segura Ranch”) : Ninemile formation with fossils. . Antelope Range near west base, 5 miles north-northeast of Blair Ranch (“Segura Ranch”): Dark-bluish-gray‘cal- careous shale, possible Caryocarls shale. . Antelope Range. north of mouth Ninemile Canyon at range front: Cherty shale and sandstone probably represents Ordovician Vinini formation outlier; no graptolites. found. Fossils in limestone of the Nevada formation to east. Northern half Antelope Valley area (pl. 1) Mahogany Hills on west side north of Table Mountain: Small erosion remnant of Cretaceous Newark Canyon formation resting on Devils Gate limestone. Plant fragments. . Mahogany Hills on west side north of Table Mountain: Upper part of the Nevada formation with Stringocepha- lus. Mahogany Hills on west side north of Table Mountain: Upper part of the Nevada formation with Stringe- cephalus. South end of Mahogany Hills, 11/2 miles north of Wood Cone: Upper part of the Lone Mountain dolomite with silicified fossils in dark-gray carbonaceous dolomite. '. Mahogany Hills, south of Table Mountain: Disconformity between Lone Mountain dolomite and fossiliferous Ne- vada formation. . South end of Mahogany Hills, north of “'ood Cone near road: Hanson Creek formation with fossils. Halyxites found northwest of locality 76 may be in either Hanson Creek or overlying dolomitic limestones of the Roberts Mountains formation. 665243 0-63— 5 77. 78. 79. 81. 82. 83. 84. 86. 87. 88. 89. 91. '. North end of Monitor Range, 61 Northern half Antelope Valley area (pl. 1)—Continued West side of Mahogany Hills, southwest of Table Moun- tain : Lower part of the Nevada formation with “Splrtfer” kobehana. South end of Mahogany Hills, on south spur of Combs Peak: Lower and middle parts of the Nevada formation with abundant fossils. East side of Yahoo Canyon near mouth, west of Devils Gate just south of Lincoln Highway: Ordovician shale and chert of the Vinini formation with graptolites. .East side Yahoo Canyon, three-quarters mile south of , Lincoln Highway and one-half mile south of locality 79: Ordovician shale and chert of the Vinini formation with graptolites. North end of Mahogany Hills, 2 miles south of Hay Ranch: Devils Gate limestone with Pachyphpllnm. North end of Monitor Range, on east side of Twin Spring Hills :Permian Garden Valley formation near base, with corals and brachiopodsf North end of Monitor Range, in Twin Spring Hills: About same horizon as locality 82. North end of Monitor Range, in Twin Spring Hills: Shale of the Vinini formation with graptolites. ’ in Twin Spring Hills: Pogonip limestone with Palllseria. North end of Monitor Range, in Twin Spring Hills: Pogonip group with fossils. North end of Monitor Range, in Twin Spring Hills: Pogonip group with fossils. East side of Antelope Valley on road 3 miles south of Lincoln Highway: Pediment outlier of limestone breccia- conglomerate. Exposure mainly depositional limestone breccia-conglomerate of Devils Gate subjected to strong deformation. Yahoo Canyon, 2% miles south of Lincoln Highway: Out- crop of dark gray bedded chert; possible Vinini forma- tion outlier. group, Antelope Valley . East side of Twin Spring Hills: Small pediment exposure Silurian platy limestone of the Roberts Mountains forma- tion with M onograptus; may also include limestone of the Hanson Creek formation. North end of Twin Spring Hills: Sandstone of probable Cretaceous Newark Canyon formation. REFERENCES CITED Bassler, R. S., 1941, The Nevada early Ordovician (Pogonip) sponge fauna: U.S. Natl. Mus. Proc., v. 91, no. 3126, p. 91—102. Boucot, A. J ., 1957, Revision of some Silurian and Early Devo- nian spiriferid genera and erection of Kozlowskiellinae, new subfamily: Senckenbergiana Lethaea, v. 38, p. 311—334. Cloud, P. E., J r., 1942, Terebratuloid Brachiopoda of the Silurian and Devonian : Geol. Soc. America Spec. Paper 38. Cooper, B. N., and Cooper, G. A., 1946, Lower Middle Ordovician stratigraphy of the Shenandoah Valley, Virginia: Geol. SOC. America Bull., v. 57, p. 35—114. Cooper, G. A., 1956, (hazyan and related brachiopods: Smith- sonian Misc. Colln., v. 127, pts. 1, 2. 62 PALEOZOIC ROCKS OF ANTELOPE VALLEY, EUREKA AND NYE COUNTIES, NEVADA Cooper, G. A., and Cloud, P. E., J r., 1938, New Devonian fossils from Calhoun County, Illinois: Jour. Paleontology, v. 12, p. 444—460. Cooper, G. A., and Williams, J. S., 1935, Tully formation of New York: Geol. Soc. America Bull., v. 46, p. 781—868. Cooper, G. A., and others, 1942,. Correlation of the Devonian sedimentary formations of North America: Geol. Soc. America Bull., v. 53, p. 1729—1794. Crickmay, C. H., 1952, Discrimination of Late Upper Devonian: J our. Paleontology, v. 26, no. 4, p. 585—609. 1953, Warrenella, a new genus of Devonian brachiopods: Jour. Paleontology, v. 27, no. 4, p: 596—600. Dunbar, C. 0., 1918, Stratigraphy and correlation of the Devo- nian of western Tennessee: Am. Jour. Sci., v. 46, p. 732—756. 1920, New species of Devonian fossils from western Tennessee: Connecticut Acad. Arts and Sciences Trans, v. 23, p. 109—158. 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Whittington, H. B., 1948, A new Lower Ordovician trilobite: J our. Paleontology, v.22, p. 567—572. 1956, Type and other species of Odontopleuridae (Trilo- bita) : Jour. Paleontology, v. 30, p. 504—520. Wilson, Alice E., 1924, A new genus and a new species of gas- tropod from the Upper Ordovician of British Columbia: Canadian Field-Naturalist, v. 38, no. 8, p. 150—151. 1926, An Upper Ordovician fauna from the Rocky Moun- tains, British Columbia: Canada Dept. Mines, Geol. Survey Bull. 44, Geol. ser. 46, p. 1—34. Yochelson, E. L., 1957, Notes on the gastropod Pallisem‘a robusta Wilson: Jour. Paleontology, v. 31, no. 3, p. 648. Abstract ................ Acknowledgments Acrotrcta eurckcmia- - 21 Aanostuc sp ........ , Alexa formation. - - ___________ Algae, Devonian -- Mississippian- ......... Ordovician - _ Silurian ....... A111 ‘is, Devonian - 53 Amphipora ...... Ancurodella curvata Anomalorthis ................................. 30 lanenm'a“ ............................. 25 1 yi- _ 25 zone ............................. 24, 25, 26, 27, 30 A fi-thcca "," ‘ ---- 43 Antelope Valley limestone ................. 23-25, 60 Apatolccphalusflnafia ......................... 21 Aphcoorfhio ................................... 21 Arena comm domain- 23 Archaeoscyphidae ............................ 25 Arline formation .............................. 2‘7 Asaphus curiosus zone ......................... 23 quadraticaudatus .......................... 24 Athuris anaeticoidcs ............................ 54, 55 Airy/pa Montana _____________________________ 53, 54 monianc-naia .............................. 53 sp ........... ’_ ......................... 38, 43, 53 B Barrel Spring formation ....................... 27 Bay State dolomite ______ - -- 45, 46 Beacon Peak dolomite- _ _ _ - ......... 45, 46 Bear Rock formation of Canada-- ___________ 49 Beaverfoot formation of Canada-. . 33 Bibliography .................. See also particular genus. Brock Canyon .......................... - - 34 Bromide formation. 27 Bryontodua ........... - - 56 Bryozoans, Ordovician ..... 24,25, 26, 32 Bumasius __________________ - - 26 Burtonia ..................................... 59 C Calathium sp ............. 25 Caledonian deformation ....... 36 Cambrian system, general discussion-- -. 14 Camcrella umbenata ............... Carbon Ridge formation ............ Caraway-apt“: ....................... foliurn. . Caryacan‘a ........................... 16, 17, 20, 21, 35 curvilata... .............. -----....... ..... 2i shale. . ---. ............................ 14, 16, 35 INDEX Cass Fjord formation of Greenland- __________ 22 Catcnipora ..................... 32 Caves _____ ‘- ---- 50 Cedar Valley limestone- 49 Cephalopods, Ordovician_- - 26 Chainman shale. - - -- - -- 56, 57—58 Charnac Basin._ 2, 9, 33, 34, 37 Chert,laminated- --- 14,16 Chonetes macrostriata 46 sp ............... 43 Chonophullum rnfumiibulum- 53 Chushina formation of Canada _______ Cladopora ........................... Climacooraptus bicornis . . - - 35 hasfaius ........................ 32 nwdestus _______________________ 35 porous _______ 26 tridcntatus maximum-H 32 Clinton formation _________ - 38 Coeloclema .................................... 24 Columnurr‘a ___________________________________ 32 alveolata .................................. 33 Conchidium ___________________________________ 32 Confusion Range .............. 48, 55 Conglomerates. limestone cobble .............. 59 Cormdiuus burlinai ____________________________ 16 Conodont facies ...... 12 Conodonts, Devonian _____________________ 42, 56, 58 Mississippian ............................ 58 Cooper, G. A., quoted ________________________ 25, 27 Copenhagen formation ....................... 25—27 Corals, Devonian .............. 42, 46, 49, 51, 53, 54, 55 Ordovician ......................... 30, 31, 32, 33 Permian _________________________________ 59 Silurian ............................ 37, 38, 40, 41 See also particular genus. Cornell University, collaboration with ________ 5, 12 Cotter area ................................ 29. 30, 45 C'renispirifcr .................................. 59, 60 Crinoids, Devonian ........................ 42, 43. 47 Silurian __________________________________ 4f) Cristi/mm cristr'fera ........................... 27 Orurithuris .................................... 59, 60 Cruptolifhus .................................. 26, 32 Cyclococh'a ____________________________________ 26 Curiocerac .................................... 26 Cyrfoepirifer ....................... --- 53, 55 porfac ....................... - 54 zone ...................................... 53, 55 Cystoids, Ordovician ______________________ 23, 25, 32 D Dalmanella sp ________________________________ 43, 54 » Dalmanites sp _________________________________ 43 Dasycladaceanalgae..------------------‘ ______ 38,-11 Depositional environment. Eureka quartzite-- 30 Dcemorthia zone ............................... 25 Devils Gate limestone ...................... 2. 49—56 Devonian rocks, general discussion ____________ 41-42 late. Sec Pilot shale. Diamond Peak formation _____________________ 57—58 Diatomnceous deposits. ....... 2, 3 Dicclloaraptus afiinis. - - ______ 32 complanatus ornatus- - - 32 Dicoclosia sp ...... 38 Dic’ranoarapfus sprmfcr- 35 Dictaomma ................................... 35 Page Didymograptus artua __________________________ 35 ""' 35 ‘ sp ........................................ 23 Dielasma _____________________________________ 59, 60 Diptograptm anamtz‘folius ...................... 35 Disoonformities, pre-Oriskany ............. 36, 40, 42 Disphyllum ................................ 41, 53, 54 Dolomitization ____________________________ 12, 13, 20 Drag folds .................................... 42 Dry Lake anticlinal arch ...................... 7, 45 ‘ Dunderberg shale ............................. 14, 16 E Eccyfiopterus sp ............................... 23 Ectenaspis homalonotoidcs _____________ 26 p. i . . . __ 24 Elkania hamburncrm'a ................. 16 Elkia nacuta- 16 Eloinia ..... 16 Ely mining district- - 47, 50 Ely Springs dolomite- - 31, 32 Endoceraa -------- 25, 26 sand ....................... 26 Englemann, Henry, explorations of. - 5 Eoplcctodonta alternata ---------- Emrinaothyria -------- Eureka mining district Eureka quartzite ----------------------------- 27—31 Eurrkia _ 21 or ' ------- 16 F Facies, change of ------------------------------ 47 Devils Gate limestone_ 54 Ordovician -- 17 Famennian fossils 55 Faults ____ .. _ ‘ 7‘9 Fauna] zones. - Sec particular zone. Favorites sp ----------------------------------- 43 Fish Haven dolomite -------------------------- 31, 33 Flume formation of Canada ------------------- 55 Fold s _ .. . 42 Fossils, assemblages, silicifled ----------------- 41 Frasnian --------------------------------- 54, 55 land plants---- 58 locality register --------------------------- 60—61 Wolfoamp -------------------------------- 59 Sc: also Algae; ammonoids; brachi- opods; bryozoans; cephalopods; conodonts; corals; crinoids; cys- toids; gastropods; graptolites: os- traoodes; radiolarians; sponges; trilobites; discussion under par- ticular formation; and particular genus. Frasnian fossils ------------------------------- 54, 55 Fusulin ids ------------------------------------ 59, 60 -G Gala beds of Great Britain -------------------- 38 Garden City formation ----------------- 22, 23, 25, 35 Garden Valley formation ----------------- 2, 34, 58~60 Garden Valley-Vinini contact ----------------- 5S, 5 9 Gastropods, Devonian ----------------- 54, 55 Ordovician ------------------------- 11, 24, 25, 60 Sec also particular genus. Gazelle formation ----------------------------- 41 Geological Survey of the Fortietb Parallel ----- 5 65 66 Page Geragnostus ................. . ................. 16 0;: ” . - - - - - 25 Givetian fossils _______________________________ 47, 54 Glenogle shale of Canada _____ Gluptorthis imculpta ......... sp _________________ Goodwin limestone- . Graptolites, Ordovician.. .._ 23, 31, 32, 33, 34—36 Silurian ___________________________________ 38 See also particular genus. Graptolitic shale ______________________________ 34 Great Basin, western subprovinoe ............. 33 Guilmette formation .......................... 47, 48 H Huh/sites ......... . ................... 37, 38, 41 (Catenipora) sp ........................... 33 Hamburg dolomite ............................ 30 Hanson Creek formation ______ .. 31—33 Hare Indian River shale of Canada 49 Bass, W. IL, quoted .............. 56 Hay River formation of Canada _______________ 55—56 Helderberg-age fauna ......................... 43 strata ..................................... 41 1,. .. . sp _____ _ 23 Heaperonomia antelopensis .................... 23 Hesperorthis antelopenris ...................... 27 Heterorflu'e sp ................................. 33 En , iu- - 47, 49 Hibbardella .............. - - .............. 56 Hidden Valley dolomite. . 39, 41 Hindcoelta .................................... 56 1! ,--l- u sp. . _ 38 Homotreta eurekemis .......................... 16 I' " " .-.. .- 40,41 zone ...................... . ............ 36, 40, 43 Hustedia mormom’. 59 Hypothyridma emmomi .................... 53, 54, 55 venustula ........ .. 54 Hyatricurua ravm' .............. 21 americanus _______ Independence shale ___________ 54 Introduction _________________ 2—6 Investigations, history of ...................... 5—6 paleontologic ............................. 9-12 purpose and scope of .............. .. . 6 Inyo Mountains ......... 29, 30, 31, 32, 38, 39, 40, 41, 55 Irvingella ........ 16 Y ‘ ' "' ____ _____ 23 Ieotelus _______________________________________ 26 Ischyrotoma twenhofeli ..... . 24 Isophragma ponderosum _______________ _ 27 J Jerome formation _____________________________ 55 Joana limestone. _____________________________ 56, 57 K Kainella fiagricaudus __________________________ 21 zone ______________________________________ 21 Kainefla-Nanorthis fauna.. _-_ 17, 20 Kirkella vigitam _____________ King, Clarence, investigations by. ....... 17, 27 Klamath Mountains __________________________ 41 Klamath Silurian _____________________________ 36 Kobeh Valley __________ _ 2, 50 Kobeh Valley Lake_. . ..... 5 Kozlowskiellina __________________ 43 L Laketown dolomite ..... Lava flows, chloritined .. - 33 INDEX Page Ledbetter slate ............................... 35 Leiorhynchus castanea ......................... 46, 49 Leiostegium manitouenses _____________________ 21 Leonaspis tuberculatus ...... _ 43 Leperditiu bivia ................................ 25 sp ....... 24 Lepidocyclae. ____________________________ 32, 33 T r ‘ v. ‘ ' ‘ __ . 27 rhomboidalis ............... 43 Leptella nevademis ............................ 23 Leptellina zncompta ........................... 27 Leptograptus fiaccidus epinifer trentonemis- _ . _ 35 Love nea when rinata _________ . _ 43 Liaonodina ............... . 56 Lincolnshire limestone ________________________ 27 Lingual sp .................................... 23 Linaulasma occidentale. _ _ . 27 Linouletta sp _______________ 21 Lia:atrupa-... _____ 41 Lonchadomus ................................. 26 Lone Mountain ............................... 2, 11, 29, 30, 31, 35, 38, 39, 40, 43, 45, 46, 57, 58 Lone Mountain limestone __ 31, 36, 39-41 Lophospira sp .................... 25 Lost Burro formation _________________________ 55 Lotagnostus trisectus ........................... 16 M Macgeea.. ......................... 53, 54, 55, 56 Maclurites .................................... 23, 24 manna ................................... 25 Macrocoelia occidentalia. 27 Manitou formation. 22 Manticocems ...... 54 sinuosum .............................. 53 Maquoketa shale ............................. 33 Martinia kirki... _ 45, 46, 47, 48 mvadenm- _ spp ......... kirki zone ........................... 45,46, 47, 48 AIM] ‘l V r . 48 Martin limestone ............................. 55 Martin Ranch ________________________________ K 6 Martin Ridge ................................. 26, 29 Mazourka Canyon . 41 Aleristella sp. _ . . 43 M ichelinia sp. 43 Mictophyllum .......................... _ 53 Mississippian rocks, early. See Pilot shale. general discussion_. ModocPeak.._. Monograptus. awe ...................................... 38 pandas ................................... 38 Alonotrypa sp .................. 26 Mons formation of Canada .................... 22 Monte Cristo ................................. 47, 54 Montoya limestone ................ 33 Moxomia anaulata ................. 21 Mud breccia ................. 51 Muuicoatella rectangulata ______________________ 27 Murchisonia millen' ........................... 25 Mycophyllum sp .............................. 38 N N anorthis hamburvemis ....................... 21 multicostata _______________________________ 21 Nevada formation _________________ _ 41, 44-49 Newark Canyon formation ................ 2, 7, 58, 59 Newark Mountain ......... _ 50,51,53, 54,56 N inemile Canyon fault _______________________ 14, 16 Ninemile formation ........................... 22—23 Nudirostra walcotti .................. .. 54, 55 Nunatami beds of Greenland __________________ ‘23 0 Obotus sp ..................................... 21 Ogden quartzite of King ...................... 19, 27 Page Oil shale ...................................... 33 Onm'ella quadrata ............................. 33 Onondaga facies .............................. 49 Onondaga formation- .. 43, 49 Oranda formation ............................. 27 Ordovician-Silurian boundary ................ 36 Ordovician system, general discussion.. _. 16—17 0th is tricena ria _______________________________ 25 sp ........................................ 24, 25 Orthoceras sp.‘ ________________ ._ 25, 43 Orthograptue calcaratus trifidus. ______ 32 Orthoquartzite ________________ . . 29, 33 Orthostrophia strophomenoides _________________ 43 Ortoaraptua calcaratuc acutue .................. 35 Ostracodes, Ordovician. .. . _ _ .. 24 Ozoplecia ........................ 26 monitorensis ............. 27 nevadensia ................................ 27 Oxyoke Canyon .............................. 40, 45 Oxyoke Canyon sandstone ................. 44,45, 46 P Pachyphyllum .......................... 53, 54, 55, 56 zone _____________________ I Paleoeoology .......... Paleozoic rocks, gener.l discussion ...... 12—14, 56—57 Palliser formation ............................. 55 Palliseria ........ 11, 60 longwelli ..... 24, 25 zone ....... 24, 25 Palmatolepsis ........ 56 Parabolinella urgentinensis .................... 21 Parafusulina .......... 59 Paurorthis giga ntea ...... 27 Perdrix formation of Canada ............ 55 Permian system. See Garden Valley formation. Pertiaurus ....... . ............................ 23 Phacopa sp ......... 43 Phi Kappa formation ......................... 35 Phallipaastraea ............................... 53, 56 Phillipsburg mine. . . 40, 45,50 Phylloaraptus anauetifolius .......... 35 Iorinai ............. -. 23 Pilot shale ................................ 42, 56, 57 Pinyon Range ................................ 5 Plaesiomy s ...... Platyceras sp ..... Platystrophia . _ Plectorthis obese ............................... 27 Plectotroph ia .................................. 21 Pteurodictyum trifoliatum _______ Plicatolina sp. . . . ...... Pliomerops. . . . barrandei ....... nevadensis ................................ 24 Pogonip group, general discussion. 17—19, 22 Polk Creek shale .............. _ 32 Prioniodua ..... _ 56 Productella ...... 54 Prospect Mountain quartzite ................. 29 Protocycloceras foerslei ......... . 23 Prolopliomerops supercz‘liasa. . 21 Peeudagnostus prolongus _ . . - . 16 Pseudonileus sp ............................... 21 Paeudoschwagerina ............................ 59 Rseudozaphremoides- 59 Pterwometopus. 26 P1, In 1 g.‘__ ______ 1.23 P ,, " ---- -_- ..... 54,55 Punctolira punctolira ............ 21 38 Q Page Quartz monzonite, lithologic character ........ 16-17 R Rabbit Hill.-.. -- ________ 37, 38, 42, 43 Rabbit Hill limestone. ________ - 40, 42—44 Radfastraea ............ ‘ _______________________ 46 arachne ___________________________________ 49 Raphistomina latiumbilicata ................... 23 Read Bay formation of Cornwallis Island ______ 41 Receptaculites ___________________________ elongatua. - mammillaris. occidentalis ................................ 26 Remopleurides ................................ 26 Rcmselandia _____________ 11.47.49 Retiograptus geinitzianus ______________________ 35 Reuschella vespertina .......................... 27 Rhizoplwllam .................... 37 Rhynchocamara breviplicata __________ 23 subaevix ........................ 23 Rhynchotrema aramturbica ____________________ 32 Rhysostrophia zone ............................ 25 Richmond faunas, Ordovician. ...... 30 Richmond Interval..- ______ 32 Roberts Creek Mountain .......... 29 Roberts Mountains .......... 6, 11, 32, 38, 39, 45,46, 50 Roberts Mountains formation _________________ 37—39 Roberts Mountains thrust. . . . . . 7, 9, 34 Rockhouse shale ................... 44 Ross. R. J., Jr., quoted ............. ___ 32, 35,36 Rosiricellula angulala ......................... 27 S Sanidophyllum ................................ 41 Sarbach formation of Canada .................. 23 Saturday Mountain formation. 35 Schizophoria simpsom' ........ 54 Schizorarnma sp .............. _ 43 Schuchertella sp ............................... 43 Schwaaerina .................................. 59 Sedimentary facies ................. 13 Segura Ranch. See Blair Ranch. Sentinel Mountain dolomite .................. 45, 46 Sevy dolomite ................................ 41, 48 Shumardia sp ................................. 21 Sills ........................... . 56, 57 Silurian-Devonian boundary .................. 36 Silurian system, general discussion ............ 36-37 Simonson formation .......................... 47, 48 Simpson exploring expedition ................. 5 Sly Gap formtion ......... - 55 Sowerbuella merriarm‘ ......................... 27 Sowerbyites lamellosas ......................... 27 sp ........................................ 26 INDEX Page Spaghetti coral ............................... 46, 51 Spiri fer arenosa ........................ . 45, 47 argentarius ............ 51, 53, 55 cycloplerus ................................ 43 engelmanm’ ............................... 53, 55 55 kobehana ................................ 40, 45, 46, 47 modestus .................................. 43 ping/(menus. .......... 44, 46, 47, 49, 53 raj/mend: ........................ 53 swallowenszs- . ......... 43 arenosa subzone ............... ' ......... 4 5, 46. 47 argentarius zone ..................... 51, 53, 54, 55 kobehaua zone... ............ 45,46, 47 pinyonensis zone.. ............... 45, 46 Spiriferellina newelli. - . _ _______ 60 Sponge beds, argillaceous ..................... 25 Sponges, Devonian ........................... 43 Ordovician ........... 25 See also particular germs. Streptelaxma .............. Streptelasmoid ....... Stictoporella sp ........ Striatopora gwenensic .......................... 43 Stringocephalus ................... 11,45, 46,47, 48, 54 zone ................................ 45, 46,47, 49 Stromatoporoid zone .......................... 53 Stromatoporoids ............... 51, 53 Strornatotrypa sp __________ 26 Strombodes sp ............. 38 Stroph mama so ............................ 26, 27, 33 Subalites sp ................................... 25 Sulphur Spring Mountains ................ 5, 19, 4o, 42, 44, 45, 46, 48,50 Sultan limestone .............................. 55 Swan Peak quartzite ....................... 25, 30, 35 Symphyaurina. . _ . _ 21 Syntrophina _____ _ 21 Synlrophopsia polita. ............. _ 23 Syringaro’n acuminatum ....................... 43 Syringopora ................................ 53, 59, 60 System boundaries. _ 16 System limits .............................. 14 T Table Head formation of Newfoundland _______ 25 Tabulophyllum ........................... . 54, 56 Talc City ................................. . 32 Temnophyllum ............................... 53, 54 Tentaculites sp ................................ 43 Tenticospirifer utahemia. _ Tetragraptus ............................ Tetragraptus quadribrachiatus ______________ similis .................................... 35 Thaerodonta sp ................................ 33 Thaleops ...................................... 26 67 Page Tharmwpora .................................. 53, 54 Thomas Range ........................... . . 55 Three Forks formation ........................ 55 Thrust faults__ ........................... 9, 33, 42 Thrust outliers . .. . 33, 42, 50, 58 Tosto‘nia iole .............................. __ 16 Trail Creek formation ......... . _ 39 Trematopora sp ............................... 26 Trematospira ................................. 46 equistriata ................. 43 Trilobites, Cambrian_- .......... 16, 21 Ordovician ................... 11, 21,23, 32, 35 See also particular genus. Tritoechia sinuata ............................. 23 Tully limestone ............................... 54 Twin Spring Hills ................. 9, 34, 37, 58, 59, 60 Tylothvria ..................................... 53, 55 Tyrone Gap ............................ 9, 34, 40, 58 ‘ U Ubehebe area .............................. 23, 48, 55 V Valcourea plarm .................. 27 sp ............................... 26 Valmy formation ________ 35 Vegetation ................. 2 Vinini formation ............... 23, 33—36, 50, 56, 57, 58 Volcanic ash ................... 2—3 Volcanic rocks ................................ 2 W Wahsatch Limestone ......................... 44 Warrenelta .................... . 54 Waterways formation of Canada . - 55 Westonia iphia ....................... .- 16 White Pine (Hamilton) mining district ..... 47,50, 54 White Pine shale ............................. 42, 56 Whiterock Canyon .............. 9, 20,24 Whiterock stage of G. A. Cooper. . _ . 25 Windfall formation ................ .. 14—16 Wolfoamp fossils .............................. 59 Wonah quartzite ............................. 31 Wood Cone ............ 31, 37, 38, 41 Woodpecker limestone ....................... 45, 46 X Xenorthia sp .................................. 16 Xenoatem'urn belemnura ....................... 21 Y Yellow Hill formation ........................ 23 Yucca Flat-Frenchman Flat area .......... 48, 50, 55 Z quoapira sp .............. 33 U15. GOVERNMENT PRINTING OFFICE : I963 0—8852.) ,w flaw: NVlWHBd NVDIAOOHO Awmxoom :5 mm I O mvmmmm as £92.35“. .3: “.555: MUON arm ~ 3%» % ~ 1% ~ ME. 53:? :33: Sm 3:82 :25 4 ms 3%. 55:. fix .3 sfi. Sum. 22a ins... 1111111 3338 223 3.3. .E a~3§§§u§3§§ x mans—M QEQMQA A sitasaa325m ‘ 3.233% £355: 2.3 guisaessexufisssez $.39: .geeELQ “BED geagamw 33:3: uSaflcfiwbmvns 65.5% was 5633.5 .53: a 55:58 5.552 § § 3:: EE 23° t: :33 s: 2. =§§o 9.83 360 £169 NVIHn‘IIS GNV NVDIAOCIHO NVIDIAOGHO NVINOAEG Eighwx §e§2 15. 33:. .35 23s :2. :33 s: 353: 3.5: $3835: 360 3.53 33.3.: w3¢5=uuouu€== .33.. air—can coca $5.525: .EUSNEEu “.an 95:55 we» 25: 55530 .25? fit 23 «o 9:3 $.52 35» use is: 3:335 segue i=5 NVIddISSISSIW \\\\\\\ SHOHEJINOGHVD § 950: U_ONOm..u4 (mm 252 m. 23.50 hum... on ._<>m_m_.z_ KDOFZOU _ ww.=£ w _ _ _ _ _ . _ v N o N mmHEHAMZ “mum—MAN WMAASV MAHOAMBZ< hwgflm ZMHEEMOZ .m<2 MOZ956 $25.30 mi :3: amE wmmm NEE «ASHE m \ooo «IL \ q ,, \\\» \\\ \ v“ V 1* Q \\‘ \\\\\\\\\\\\\\ \\ \\\\§§\\\\ \\\\\\\ \\.\ \\\\\\ \\ \\ \ \ N _ 525. C55; to»: *mmkb {3K huskkm. 3t 74%;) >fiur>>Tfixnn< z_m A>V4\h 4A»4»A 7 .Jr ,3 A «v «mpg? obfmgfi; W N 1024”. > Immox .0m.mm _ whin— .nuv mmmm>~5w AV~>L>SR°VH75>mfi>vvp‘4rvr,réfl-, " “AVWA> >Li7AA-14A‘Pv": A r A Is u.» n;«)<fl“ 1 l- 4/ > «SC/(v) I, {VB-GALDKMINC' n): I)? A > n u z. 7 (J< I," A (v prawns/.1 )g-IU A 4 < < 4 ,~ \ (5500-qu I; <( "> ”A ‘wv L J»! Avki" r~\ \ V)3r7‘7 / (—‘JZAV7AA W; k_7 < 1; / / 4&— AVATriAAc (“r7 < C? “will? \fi //\ r,r~v_‘)" v / ,’ 4 >" A 9° 2 f l 3” A>7$ ”’3 / I / /\ / \ / (,0 / // New? U H 33) x} / 5(449 [V \I/‘ \/ [7 (r- \ \2 l / / ) J \ t,- \ i r\\)(j/( [i///// j/I f//j~?//-/ \/ )L] K ,\ K V \ \ / / \“7 fl L ~M‘ \ -\\ \K////}\Y’\ {ll/(”22 > (f ijjrfi “7‘ IU/\I(T/> \ Base man lrom US. Geological Survey Roberts Mountains. quadrangle, 1929 Geology by C W. Merriam, C M. Nevin, and L. E. Nugent, 1940—50 GEOLOGIC RECONNAISSANCE MAP, SOUTHERN HALF ANTELOPE VALLEY AREA, NEVADA, SHOWING FOSSIL | I l I l I | CONTOUR INTERVAL 500 FEET DATUM IS MEAN SEA LEVEL LOCALITIES ? MILES 39'IS’ E X P LA N ATI O N __77 ~ LE. *1 Younger igneous rocks E Mainly volcanic S 'E m |— Older igneous rocks Intrusive .I %% 3 Nevada formation 2 l O > u c: .J z 5 > g :A m Roberts Mountains formation .4 Hanson Creek fomfion WESTERN FACIES PALEOZOIC R0 C K S 7 /% é Eureka quartzite 5-) > . . . o men formation - g Gmpwlitic sham and chart: 0 Pogonip group and over- lying Copenhagen for- mation Lwally include: Windfall formation 2 5 an F Windfall formation E Contact --------- Dasha! where indqfinitc —Fnu1? Dasha! where approximately located, domed where concealed W Thrust fault Saw mu: on m qfupper pm; A 72 Fossil locality See locality register ml: loam Anion-u" um- MchAnol. in: 665243 0 - 63 (In pocket) 0RDOV|CIAN :15 fl ,4: 424~14 Geological Survey Research 1961 Synopsis of Geologic and Hydrologic Results 1’! (5} IL} GEOLOGICAL SURVEY PROFESSIONAL PAPER 424—A EARTH SCIENCES LHLRARY Geological Survey Research 1961 THOMAS B. NOLAN, Director GEOLOGICAL SURVEY PROFESSIONAL PAPER 424 A ynopsz's ofgea/agz'c and fiydrologz'c results, ac'compam'ea’ éy sflart papers in Me geolagz'c and @ya’ro/ogz'c sciences. Pué/z'sfléa’ separateZy as cfiapters .4, B, C, and D UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON :1961 FOREWORD The Geological Survey is engaged in many different kinds of investigations in the fields of geology and hydrology. These investigations may be grouped into several broad, inter- related categories as follows: (a) Economic geology, including engineering geology (b) Regional geologic mapping, including detailed mapping and stratigraphic studies (0) Resource and topical studies (d) Ground-water studies (e) Surface-water studies (f) Quality-of-water studies (g) Field and laboratory research on geologic and hydrologic processes and principles. The Geological Survey also carries on investigations in its fields of competence for other Fed— eral agencies that do not have the required specialized staffs or scientific facilities. Nearly all the Geological Survey’s activities yield new data and principles of value in the development or application of the geologic and hydrologic sciences. The purpose of this report, which consists of 4 chapters, is to present as promptly as possible findings that have come to the fore during the fiscal year 1961—the 12 months ending June 30, 1961. The present volume, chapter A, is a synopsis of the highlights of recent findings of scientific and economic interest. Some of these findings have been published or placed on open file during the year; some are presented in chapters B, C, and D; still others have not been pub— lished previously. Only part of the scientific and economic results developed during the year can be presented in this synopsis. Readers who wish more complete or more detailed informa— tion should consult the bibliography of reports beginning on page A—156 of this volume, and the collection of short articles presented in the companion chapters as follows: Prof. Paper 424—B—Articles 1 to 146 Prof. Paper 424—C—Articles 147 to 292 Prof. Paper 424—D—Articles 293 to 435 A list of investigations in progress in the Geologic and Water Resources Divisions with the names and addresses of the project leaders is given on pages A—110 to A—155 for those in— terested in work in progress in various areas or on special topics. During the fiscal year 1961, the services of the Geologic and Water Resources Divisions were utilized, or supported financially in part, by the many Federal and State agencies listed on pages A—106 to A—109. The Geological Survey has also cooperated from time to time with other agencies, and some of the work described in these chapters stems from work of previous years in cooperation with agencies not shown on the list. All cooperating agencies are identi— fied where appropriate in the individual short articles in chapters B, C, and D, and they are mentioned in connection with some of the larger programs summarized in chapter A; because of space limitations, however, their contributions are mentioned in many of the short summary paragraphs contained in chapter A. The many cooperating agencies, by means of financial support, technical cooperation, and friendly counsel, have contributed significantly to the findings reported in these chapters. This report, which was prepared between March and July 1961, represents the combined efforts of many individuals. Paul Averitt assumed overall responsibility and assembled chap- IV FOREWORD ter A from information supplied by project chiefs and program leaders. Arthur B. Campbell and William J. Mapel critically reviewed most of the manuscripts submitted for chapters B, C, and D. They were assisted in this task by Stanley W. Lohman, Edward T. Ruppel, Paul K. Sims, and Vernon E. Swanson. Mrs. Virginia P. Byers helped check, process, and assemble the papers. R. A. Weeks and Charles J. Robinove compiled the lists of cooperating agencies and the list of investigations in progress. Barbara Hillier compiled the list of publications. Edith Becker and Marston Chase prepared the indexes to chapters B, C, and D. To these must be added the many contributors of articles, summaries and ideas. I am pleased to be able to acknowledge here the contributions and efforts of these individuals. GELWAM THOMAS B. NOLAN, Director. Synopsis of Geologic and Hydrologic Results Prepared by members of the Geologic and Water Resources Divisions GEOLOGICAL SURVEY RESEARCH 1961 GEOLOGICAL SURVEY PROFESSIONAL PAPER 424—A A summary ofrecent ycientzfi c ana’ economic rem/ex, accompanied é} a [in‘ ofreport: released infisca/ 1961 ana’a 1th of investigations in progres: UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON :1961 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing OfliCC Washington 25, D.C. CONTENTS Resource investigations ______________________________ Heavy metals __________________________________ District and regional studies _________________ Montana iron deposits __________________ Chromite deposits of the Stillwater com- plex, Montana _______________________ Nickeliferous lateritic soils in the Klamath Mountains, Oregon and California ______ Tungsten and molybdenum in the Rocky Mountains ___________________________ Manganese and zinc deposits near Philips- burg, Montana _______________________ Studies in Colorado _____________________ East Tintic silver—lead district, Utah ______ Central mining district, New Mexico ______ Lead, zinc, and related ores of the Central and Eastern States ____________________ Gold in California ______________________ Commodity studies _________________________ Topical studies _____________________________ Heavy metals and trace elements in black shales and phosphorites ________________ Light metals and industrial minerals ______________ District and regional studies _________________ Beryllium at Spor Mountain, Utah ________ Beryllium in the Mount Wheeler area, White Pine County, Nevada ___________ Beryllium in the Lake George district, Colorado _____________________________ Pegmatites of the Spruce Pine district, North Carolina _______________________ Vermiculite deposits in South Carolina_ - - _ Fluorspar in the Browns Canyon district, Salida, Colorado ______________________ Phosphate deposits in the Southeastern States _______________________________ Clay in Maryland _______________________ Clay in Kentucky _______________________ Borate in California _____________________ Pumice and pozzolan deposits in the Lesser Antilles ______________________________ Commodity and topical studies _______________ Beryllium ______________________________ Potash ________________________________ Radioactive materials ___________________________ District and regional studies __________________ Colorado Plateau _______________________ Shirley basin, Wyoming _________________ Coastal plain, Texas ____________________ Front Range, Colorado __________________ Powderhorn district, Colorado ____________ Page A—-1 1 1 1 #8 Kit-FREQ: 03030303 as»; 01 9010101 KIKIKIKIODQGQ®®G> wmmwv Resource investigations—Continued Radioactive materials—Continued Topical studies _____________________________ Epigenetic deposits of uranium in limestone- Geology of uranium deposits in sandstone-- Source of monazite in some Australian placers_ _____________________________ Fuels __________________________________________ Petroleum and natural gas ___________________ Coal ______________________________________ Coal fields of the United States- _ _ - _ _ - _ - - - Coal resources of Arkansas _______________ Geology of specific coal fields _____________ Spheroidal structures in coal _____________ Oil shale ___________________________________ Water _________________________________________ Regional and district studies _________________ Distribution and characteristics of stream- flow _________________________________ Water use _________________________________ Water use in river basins of Southeastern United States ________________________ Copper industry- _ _' --------------------- Styrene, butadiene, and synthetic rubber industries ____________________________ Regional geology and hydrology ---------------------- Synthesis of geologic data on maps of large regions- Mineral distribution maps ___________________ Tectonic map of the United States ------------ Paleotectonic maps of the Permian system _____ Pleistocene lakes in western conterminous United , States ___________________________________ New England and eastern New York _____________ Regional geologic mapping in Maine_ - _ _ _ _ - _ - _' Regional geologic mapping in Vermont ________ Regional geologic mapping in Massachusetts , and Rhode Island _________________________ , Regional geologic mapping in Connecticut ----- ‘ Geophysical surveys _________________________ 3* Economic studies-_________-_____-_____-__--; Geochemical studies in New Hampshire ------- ' Aquifers composed of glacial deposits ---------- ' Occurrence of water in bedrock --------------- : Chemical and physical quality of surface and ground water ---------------------------- Flood magnitudes --------------------------- Appalachians ___________________________________ Geologic mapping --------------------------- Structural and tectonic studies _______________ Stratigraphic studies in the Ridge and Valley province _________________________________ Geophysical study in the Maryland Piedmont-- V11 Page ooooooooooooooqxlxlq KIN" coco 10 11 11 11 11 12 12 12 12 12 13 13 14 14 14 14 14 15 15 15 16 16 VIII Regional geology and hydrology—Continued Appalachians—Continued Streamflow _________________________________ Sediment yield _____________________________ Atlantic Coastal Plain ___________________________ Geochemical and petrographic investigation in Florida __________________________________ Geologic mapping ___________________________ Hydrologic studies __________________________ Eastern Plateaus _______________________________ Geologic mapping in Kentucky _______________ Quaternary geology of the lower Ohio River Valley ___________________________________ Geologic history of Teays Valley, West Virginia- Paleontologic studies ________________________ Hydrologic studies in Kentucky ______________ Flood frequency areas in New York ___________ Shield area and Upper Mississippi Valley __________ Geologic studies and mapping ________________ Geophysical surveys _________________________ Hydrologic studies __________________________ Gulf Coastal Plain‘and Mississippi Embayment---- Correlation of the Carrizo sand in central Mississippi Embayment ___________________ Pliocene(?) stratigraphy of the northern Missis- sippi Embayment _________________________ Effects of Pleistocene and Recent weathering of Tertiary sediments ________________________ Ground-water storage _______________________ New sources of ground water _________________ Occurrence of salt water _____________________ Ozark Region and Eastern Plains _________________ Aeromagnetic studies in northeastern Arkansas and southeastern Missouri _________________ Arkoma basin, Arkansas and Oklahoma _______ Atoka formation in the Arkansas Valley, Arkansas ________________________________ Development of the Fredonia anticline in Wilson County, Kansas __________________________ Austin chalk, Val Verde and Terrell Counties, Texas ___________________________________ Movement underground of artificially-induced brine _____________________________________ Buried valley near Manhattan, Kansas ________ Depressions on the High Plains _______________ Salt water and halite at shallow depths in Oklahoma _______________________________ Water withdrawal in Reeves County, Texas_--- Aquifer filled in Haskel and Knox Counties, Texas ___________________________________ Reservoir evaporation ________________________ Northern Rockies and Plains _____________________ Geologic studies in northeastern Washington and northern Idaho _______________________ Geologic studies in central Idaho _____________ Geologic and geophysical studies in western Montana ________________________________ Alternative hypotheses on deformation accom- panying the Hebgen Lake earthquake, Montana ________________________________ Geologic and geophysical studies in the Bear— paw Mountains, Montana _________________ CONTENTS Page A—16 16 16 16 17 17 18 18 18 18 18 19 19 19 19 19 20 20 20 21 21 21 21 21 22 22 22 22 22 22 22 22 22 22 23 23 23 23 23 23 24 24 25 Regional geology and hydrology—Continued Northern Rockies and Plains—Continued Geologic and geophysical studies in parts of Wyoming, southeastern Idaho, and north- eastern Utah ______________________________ Stratigraphic studies in parts of eastern Mon— tana and Wyoming _______________________ Geologic and geophysical studies in the Black Hills, South Dakota and Wyoming __________ Possible Early Devonian seaway ______________ Biostratigraphic studies of upper Paleozoic rocks ____________________________________ Ground-water investigations in Idaho _________ Ground-water investigations in Montana ______ Ground-water investigations in Wyoming ______ Ground-water investigations in North Dakota-_ Ground-water investigations in South Dakota- _ Southern Rockies and Plains _____________________ Geology of volcanic terrains in Colorado and New Mexico _____________________________ Geology of Precambrian rocks ________________ Geology of major sedimentary basins __________ Rocks of Mississippian and probable Devonian age in the Sangre de Cristo Mountains ______ Geology of parts of Nebraska ________________ Ground-water recharge ______________________ Ground-water storage _______________________ Buried channels ____________________________ Hydrogeology of Denver metropolitan area_ _ _ _ Relation of ground-water quality to bedrock--- Ground-water development in New Mexico_ __ - Distribution of moisture in soil and near-surface tuff _____________________________________ Colorado Plateau Province _______________________ Stratigraphy _______________________________ Paradox basin ______________________________ Geomorphology and physiography ____________ Hydrologic studies __________________________ Basin ane Range Province _______________________ Thrust faults in Nevada and Utah ____________ Other structural features _____________________ Studies of Cambrian and Precambrian rocks- - _ New data on Cretaceous rocks ________________ Emplacement and age of intrusive bodies ______ Tertiary volcanic rocks and calderas __________ Quaternary history __________________________ Ground-water occurrence and movement in pre-Tertiary rocks ________________________ Hydrogeochemistry _________________________ Specific yield of sediments ___________________ Floods and mudflows ________________________ Columbia Plateau and Snake River Plains _________ Laumontite stage metamorphism of Upper Triassic rocks, Aldrich Mountains, Oregon-- Facies changes in the John Day formation ----- Volcanic ash falls used as stratigraphic marker beds ____________________________________ Gravity anomalies __________________________ New data on the age of the Columbia River basalt ___________________________________ Southward transgressive overlap of the basalt-- Landforms of Pleistocene age in the Snake River Plains ___________________________________ Page A—25 25 25 26 26 26 26 27 27 27 27 28 28 28 29 29 29 29 29 30 30 30 31 31 32 32 32 33 33 33 34 34 34 35 35 35 35 35 36 36 36 36 CONTENTS Page Regional gelogy and hydrology—Continued Columbia Plateau and Snake River Plains—Continued Pleistocene American Falls lake and the Michaud gravel ___________________________________ A—36 Other Pleistocene drainage changes ___________ 36 Basin discharge studies ______________________ 36 Quality of ground water _____________________ 37 Ground water in basalts _____________________ 37 Pacific Coast region _____________________________ 37 Washington ________________________________ 37 Oregon ____________________________________ 37 Klamath Mountains and Coast Ranges of northern California _______________________ 38 Coastal area of central and southern California- - 38 Sierra Nevada ______________________________ 39 Hydrologic studies __________________________ 39 Alaska ________________________________________ 40 Northern Alaska ____________________________ 40 West-central Alaska _________________________ 40 East-central Alaska _________________________ 42 Southwestern Alaska ________________________ 42 Southern Alaska ____________________________ 42 Southeastern Alaska ________________________ 43 Cenozoic stratigraphy of Alaska ______________ 43 Aeromagnetic profiles _______________________ 43 Quartz diorite line __________________________ 43 Surface water ______________________________ 44 Ground water ______________________________ 44 Hawaii ________________________________________ 44 Kaupulehu lava flow, Hualalai Volcano ________ 44 New data on the 1959—60 eruption of Kilauea Volcano _________________________________ 44 Uwekahuna laccolith in Kilauea caldera ________ 45 Alumina-rich soil and weathered rock _________ 45 Geology of Kauai ___________________________ 45 Ground water in southern Oahu ______________ 45 Use of water by phreatophytes on Oahu _______ 45 Water resources of windward Oahu ___________ 46 Indian Reservations, National Parks, and Public Lands _______________________________________ 46 Saratoga National Historical Park, New York-- 46 Hydrology of the Everglades National Park, Florida __________________________________ 46 Ground-water supply of Cape Hatteras National Seashore Recreational Area, North Carolina-- 46 Hydrologic studies in Indian Reservations, New Mexico __________________________________ 46 Water-supply possibilities at Capitol Reef National Monument ______________________ 46 Hydrology of Fort Apache Reservation, Arizona_ 46 Puerto Rico ____________________________________ 47 Structural control of mineralization ___________ 47 Test well for petroleum drilled on north coast- _ 47 Ground water _______ .- ---------------------- 47 Floods of September 6, 1960 ------------------ 47 Canal Zone ------------------------------------ 47 Western Pacific Islands -------------------------- 48 Geology of Ishigaki, Miyako, Tinian, and the Yap Islands ______________________________ 48 Paleontologic studies of Okinawa, Guam, and the Fiji Islands --------------------------- 48 Regional gelogy and hydrology—Continued Western Pacific Islands—Continued Volcanic suites of Guam and Pagan, Mariana Islands ---------------------------------- Studies of drill holes in the northern Marshall Islands ---------------------------------- Investigations of typhoon damage to atolls ----- Antarctica _____________________________________ Geology of the eastern Horlick Mountains ----- Geology of central Marie Byrd Land ---------- Geology of the Thurston Peninsula-Eights Coast regions ---------------------------------- Coal in the Antarctic ________________________ Geology of the Taylor Dry Valley area --------- Granites of the Ross Sea region --------------- Glacial geology of Antarctica ----------------- Geologic and hydrologic investigations in other countries-- Thorium and rare-earth deposit, Brazil ------------ Diamond deposits in Bahia, Brazil ---------------- Uranium in the Serra de Jacobina, Bahia, Brazi1_-- - Geologic studies of iron deposits of Brazil ---------- Chilean earthquakes of May and June, 1960 ------- Origin of Chile nitrate deposits ------------------- Iron deposit in Libya ---------------------------- Fluorspar deposits of Mexico --------------------- Phosphorite deposits in Mexico ------------------- Iron deposits in West Pakistan ------------------- Mineral resources of Taiwan --------------------- New deposits of fluorite and manganese in Thailand_ - Surface-water resources of the Helmand River, Af- ghanistan ------------------------------------ Ground water in the Libyan desert, western Egypt- - River basin surveys in Iran ---------------------- Extraterrestrial studies ------------------------------ Photogeologic mapping of the Moon - - - _ - - - - _ - - - - : Lunar stratigraphy and time scale ------------ Structural features -------------------------- Terrestrial meteorite craters and impact phenomena- Terrestrial meteorite craters ------------------ Impact phenomena ------------------------- Extraterrestrial materials ------------------------ Tektites ----------------------------------- Meteorites --------------------------------- Investigations of geologic and hydrologic processes and principles ---------------------------------------- Paleontology ----------------------------------- Evolution ---------------------------------- Paleoecology ------------------------------- Systematic paleontology _____________________ Morphology -------------------------------- Stratigraphic paleontology ------------------- Geomorphology --------------------------------- Lateritic saprolite in Puerto Rico _____________ Interpretation of desert varnish --------------- Surficial geologic processes related to volcanoes- Microrelief features in arctic regions-__-- _ - _ _ - - Geomorphology of permafrost ---------------- Morphology of stream channels --------------- Mechanics of meandering and irregular channels- Eflective force in geomorphology ------------- Geomorphology related to ground water -------- Geomorphology and geology in relation to streamflow ------------------------------- Investigations of geologic and hydrologic processes and principles—Continued Plant ecology __________________________________ Relation of vegetation to soil moisture and texture __________________________________ Trees as indicators of floods __________________ Trees as indicators of glacial recession _________ Vegetation as an indicator of man’s activities-- Vegetation patterns as indicators of past cli- mates ___________________________________ Glaciology and glacial geology ____________________ Studies of existing glaciers ___________________ Glacier hydrology---- - - - - - __________________ Glacial geology _____________________________ Oceanography and marine gology _________________ Ocean crustal structure ______________________ Ecologic, zoogeographic, and paleontologic results ___________________________________ Permafrost studies ______________________________ Thermal studies ____________________________ Areal distribution of permafrost ______________ Ground water in permafrost __________________ Geophysics _____________________________________ Theoretical and experimental geophysics _______ Paleomagnetism ________________________ Magnetic properties of rocks _____________ Measurements of temperature in uranium ore bodies ____________________________ Stress waves in solids ____________________ Electrical investigations _________________ Induced polarization in rocks _____________ Seismic-electric effect ____________________ Electronic computer applications _________ Geophysical abstracts ___________________ ‘ Regional geophysics and major crustal studies- - _ Alaska ________________________________ Pacific Coast ___________________________ Sierra Nevada __________________________ Basin and Range _______________________ Rocky Mountains _______________________ Seismic studies _________________________ Other studies ___________________________ Effects of fluid withdrawal _______________ Geochemistry and mineralogy ____________________ Experimental geochemistry and mineralogy_ ___ Mineralogical studies and description of new minerals _______ ' _________________ Crystal chemistry _______________________ Experimental geochemistry ______________ Composition of water ____________________ Chemical equilibria in aquifers ___________ Geochemical distribution of the elements- _ _ Field geochemistry and petrology ____________ Diflerentiation of igneous rock series ______ Origin of carbonatites ___________________ Late magmatic processes _________________ Origin of welded tufls ___________________ Origin of accretionary lapilli ______________ Origin of zeolitic rocks ___________________ Origin of glaucophane schists _____________ Chemical changes in metasomatism _______ Chemical changes in metamorphism _______ Origin of saline and calcium sulfate deposits- Origin of clays and other sediments _______ CONTENTS Page A-63 63 63 63 64 64 64 64 64 64 65 65 65 65 65 66 66 66 67 67 67 67 67 68 68 68 68 69 69 69 69 69 70 70 70 71 71 72 72 Investigations of geologic and hydrologic processes and principles—Continued Geochemistry and mineralogy—Continued Field geochemistry and petrology—Continued Origin of ores and ore solutions ___________ Hydrothermal rock alteration ____________ Distribution of minor elements ___________ Organic geochemistry _______________________ Origin of kerogen _______________________ Biochemical fuel cell ____________________ Iron in water and plant materials _________ Isotope and nuclear studies ______________________ Geochronology _____________________________ Lead-alpha age measurements ____________ Potassium-argon, rubidium-strontium, and uranium-lead methods _________________ Carbon-14 age determinations ____________ Protactinium-thorium dating of deep-sea cores ________________________________ Light stable isotopes ________________________ Deuterium in hydrous silicates and volcanic glass ________________________________ Fractionation of oxygen isotopes between dolomite and calcite ___________________ Fractionation of oxygen isotopes as a geo- logic thermometer ____________________ Lead isotopes ______________________________ Studies of volcanic glass _____________________ Solid-state studies __________________________ Luminescence and thermoluminescence studies ______________________________ Radiation-damage studies ________________ Magnetic properties of ice _______________ Deuterium and tritium in fluids ______________ Tritium measurement technique __________ Fallout studies _________________________ Arabian studies _________________________ Model studies __________________________ Distribution of radionuclides in water _________ Hydraulic and hydrologic studies _________________ Open-channel hydraulics and fluvial sediments- Distribution of velocity __________________ Resistance to flow ______________________ Boundary form and resistance to flow in alluvial channels ______________________ Significance of fine sediment on flow phenomena in alluvial channels --------- Eflects of temperature on flow phenomena in alluvial channels ___________________ Effect of depth of flow on total discharge of bed material _______________________ Solution of unsteady-flow problems _______ Size and distribution of bed material in the Middle Rio Grande, New Mexico _______ Effects of urbanization on the supply of fluvial sediment ______________________ Surface-water hydrology _____________________ Errors in streamflow measurement ________ Use of precipitation in analysis of runoff data ________________________________ Low flow ______________________________ Peak flow ______________________________ Statistical methods __________________________ Effect of interstation correlation __________ Page A—78 79 79 79 79 79 79 80 80 80 80 81 81 81 81 81 81 81 82 82 82 82 82 82 82 83 83 83 83 83 84 84 84 84 84 84 84 85 85 85 85 CONTENTS XI Page page Investigations 0f geologic and hydrologic P10065595 and Development of exploration and mapping techniques—Con. principles—Continued Application of isotope geology to exploration _______ A—96 Hydraulic and hydrolo‘gic studies—Continued Isotope geology of lead ______________________ 96 Statistical methods—Continued Oxygen isotopes in mining districts of central Statistical properties of a runoff precipita— United States ___________________________ 96 tion relationship ---------------------- A—86 The “falling drop” method of oxygen isotope Statistical evaluation of tree-ring data _____ 86 analysis _________________________________ 96 LOW flow probability distribution --------- 86 Recording geologic information ___________________ 96 Reservoir storage—general SOIUtion Of 3' Magnifying single—prism stereoscope ___________ 96 queue model ------------------------- 86 New method of recording geologic features _____ 96 Fluctuation of annual river flows ......... 87 Hydrologic measurements ________________________ 96 Mechanics 0f flow through porous media ------- 87 Digital recorders and computer techniques _____ 96 Limnological problems --------------------------- 87 Velocity-measuring instruments _______________ 97 Salinity 0f closed lakes ---------------------- 87 Stage-measuring instruments _________________ 97 Pleistocene lake levels as indicators of climatic Velocity-azimuth-depth assembly _____________ 97 shifts ------------------------------------ 87 Well logging _______________________________ 97 Evapotranspiration ————————————————————————————— 87 Analytical and other laboratory techniques _____________ 97 Geology and hydrology applied to problems in the field of Analytical chemistry ____________________________ 97 engineering- - - - - - — — — -- — - — - —. ——————————————————————— 88 Rapid rock analysis _________________________ 97 Construction problems —————————————————————————— 88 Combined gravimetric and spectrographic analy- Urban geology ------------------------------ 88 sis of silicates _____________________________ 97 Highway geology in Alaska —————————————————— 88 Spectrophotometry __________________________ 98 Harold D. Roberts tunnel ____________________ 88 Flame photometry __________________________ 98 Subsidence ————————————————————————————————— 88 Sodium-sensitive glass electrodes ______________ 98 Clays for canal lining ———————————————————————— 88 Fatigue in scintillation counting ______________ 98 Measurement of displacement during hydraulic Silica in chromite and chrome ores ____________ 98 fracturing 0f TOCk ————————————————————————— 89 Ferrous iron ________________________________ 98 Engineering problems related to rock failure ———————— 89 Indirect semiautomatic titration of alumina____ 98 Landslides ————————————————————————————————— 89 Chemical test for distinguishing among chromite, Rock mechanics as related to mining engineer- ilmenite, and magnetite ____________________ 98 ing —————————————————————————————————————— 89 Beryllium by gamma-ray activation ___________ 99 EIOSiOH ———————————————————————————————————————— 89 Trace-element sensitivities ___________________ 99 Selection of sites for possible nuclear tests and eval- Precipitation of selenium ____________________ 99 uation of effects of underground explosions ....... 90 Colorimetric iron determinations ______________ 99 Nevada Test Site ——————————————————————————— 90 Thallium in manganese ores _________________ 99 Plowshare program _________________________ 91 Direct fluorescent procedure for beryllium _____ 99 Analysis of hydrologic data ______________________ 91 Copper in plant ash _________________________ 99 FIOOdS ————————————————————————————————————— Spectroscopy ___________________________________ 99 Ground water —————————————————————————————— 92 Development and use of the electron microprobe Interrelation between surface water and ground and analyzer _____________________________ 99 water ___________________________________ 92 Spectrochemical analysis for beryllium with a Interchange of surface water and ground direct reading spectrograph ________________ 99 water under natural conditions ————————— 92 Spectrographic analysis of minor elements in Induced infiltration of surface water _______ 92 natural water _____________________________ 99 Effect of withdrawal of ground water on Spectrochemical analysis for major constituents streamflow ___________________________ 92 in natural water with a direct-reading spectro- Effect of impoundment on ground-water graph ____________________________________ 100 flow _________________________________ 92 Mineralogic and petrographic techniques __________ 100 Low flows __________________________________ 93 Microscopy ________________________________ 100 Time of travel of water ______________________ 93 X-ray petrography __________________________ 100 Evaporation suppression _________________________ 93 X-ray methods _____________________________ 100 Artificial recharge of aquifers _____________________ 93 Staining techniques _________________________ 101 Spreading basins ____________________________ 93 Analyses using heavy liquids _________________ 101 Stream channel diversion ____________________ 93 Bulk density determinations _________________ 101 Yield deterioration in injection wells __________ 93 Sample preparation_ ________________________ 101 Geology and hydrology applied to problems in the field of US. Geological Survey oflices _________________________ 102 public health _____________________________________ 94 Main centers ___________________________________ 102 Studies related to disposal of radioactive wastes- _ _ - 94 Geologic Division field offices in the United States Distribution of elements as related to health _______ 94 and Puerto Rico ______________________________ 102 Mine drainage __________________________________ 95 Selected list of Water Resources Division field offices Development of exploration and mapping techniques____ 95 in the United States and Puerto Rico ___________ 102 Geochemical and botanical exploration ____________ 95 Geological Survey offices in other countries ________ 105 XII CONTENTS Fage Page Cooperating agencies ________________________________ A—106 Investigations in progress—Continued Federal agencies ________________________________ 106 Regional investigations __________________________ A—110 State, County, and Municipal agencies ____________ 106 Topical investigations ___________________________ 140 Investigations in progress in the Geologic and Water Re- Publications in fiscal year 1961 _______________________ 156 sources Divisions during the fiscal year 1961 _________ 110 List of publications _____________________________ 156 Index to list of publications ______________________ 183 ILLUSTRATIONS Page Page FIGURE 1. Index map of conterminous United States 4. Index map of part of Antarctica showing showing boundaries of regions ___________ A—10 areas of geologic mapping, geologic studies, 2. Index map of Alaska showing boundaries of and geologic reconnaissance by the Geo- regions _______________________________ 41 logical Survey _________________________ A-51 3. Index map of western Pacific Islands show- ing areas investigated by the Geological Survey _______________________________ 49 GEOLOGICAL SURVEY RESEARCH, I96] SYNOPSIS OF GEOLOGIC AND HYDROLOGIC RESULTS RESOURCE INVESTIGATIONS Resource investigations of the Geological Survey cover the broad fields of minerals, fuels, and water. Most of these investigations can be grouped into (a) district and regional studies and (b) commodity and topical studies. The district and regional studies are concentrated in areas known or believed to contain mineral, fuel, or water resources of present or possible future value. These studies are intended to establish guides useful in the search for concealed deposits, to define areas favor— able for exploration, and to appraise the resource potential. Most district and regional studies involve detailed geologic mapping, which adds to overall knowledge of the geology of the United States and contributes to the development of new general prin- ciples of wide application. The commodity and topical studies are more varied. They include preparation on a national basis of esti- mates of total quantities of various resources, synthesis of data on habits of occurrence of individual resources that will help define environments favorable for study or exploration, and experimental and theoretical studies on the origin, composition, and distribution of such resources. The long range objectives of both groups of studies are to determine the geologic environments in which individual commodities and mineral resources in gen- eral occur, and to develop valid theoretical principles and unifying concepts concerning their origin and oc- currence. This information provides a foundation from which private industry can extend its search for useful raw materials, and it provides the Nation with a continuing inventory of its mineral wealth. Important new findings in the fields of heavy metals, light metals, industrial minerals, radioactive materials, fuels, and water are summarized in the following pages. HEAVY METALS DISTRICT AND REGIONAL STUDIES Montana iron deposits Geologic mapping by H. L. James and K. L. Wier has shown that the Kelly iron deposit, Madison County, Mont, is a bed normally about 20 to 30 feet thick in Precambrian hornblende—diopside gneiss that is over— lain by quartzite. At the nearby Carter Creek deposit, Beaverhead County, the iron formation is a bed nor- mally about 40 feet thick in a sequence consisting mainly of dolomite marble and amphibolite. Locally, as in areas now being actively explored by private com- panies, the thickness of each bed of iron formation has been greatly increased as a result of squeezing or tight folding. Chromite deposits of the Stillwater complex, Montana E. D. Jackson, J. I. Dinnin, and Harry Bastron (1960) have shown that the Cr203 content of clean chromite from within the two minable chromitite zones of the Stillwater complex decreases upward, and that Cr/Fe values also decrease upward, enerally 40 to 50 percent from bottom to top of a zone. Both the Cran content and Cr/Fe ratios are lower in olivine-bearing chromite layers than in adjacent massive chromitite layers. This information is essential to successful de- velopment of the deposits because the low-grade chro- mite in disseminated layers near the tops of ore zones cannot be raised to commercial grade by milling. Nickeliferous lateritic soils in the Klamath Mountains, Oregon and California Field studies by P. E. Hotz (Art. 404)1 have con- firmed that several deposits of nickeliferous red soil in northwest California and southwest Oregon have been formed by weathering of peridotite. The deposits are relatively thin and of small areal extent, and hence are submarginal as nickel ore. However, a deposit at Nickel Mountain, Douglas County, Greg, is currently being mined. Tungsten and molybdenum in the Rocky Mountains Widespread occurrence of molybdenum-bearing scheelite and powellite of Precambrian age in Colorado and part of Wyoming, principally in calc-silicate mem- bers of gneissic terrains, has been described by Ogden Tweto (1960). Minor concentrations of tungsten originally present in the Precambrian sedimentary 1 Article 404 in Professional Paper 424—D. All references to articles in chapters B, C, and D are given in this style. Articles 1—146 are in chapter B; articles 147—292 are in chapter C; and articles 293—435 are in chapter D. A—l A—2 rocks were redistributed and recrystallized through successive Precambrian plutonic episodes. The de- posits found thus far are of minor economic impor- tance, but some are still being found and others probably exist. The Precambrian tungsten may have a bearing on the occurrence of the Tertiary deposits, which have been important sources of tungsten in Colorado. Through participation in the Defense Minerals Exploration Administration project in cooperation with the Molybdenum Corporation of America, at Questa, N. Mex, R. U. King, E. N. Harshman, and J. W. Hasler contributed to the discovery of a major potential source of molybdenum. In November 1960, the company announced that the project had disclosed about 260 million tons of rock containing approxi- mately 5 pounds of M082 per ton, equivalent to 760 mil- lion pounds of molybdenum metal. Manganese and zinc deposits near Philipsburg, Montana Pyrolusite, cryptomelane, todorokite, chalcophanibe, hetaerolite, manganite, and a manganese mineral that resembles synthetic gamma- and rho-MnO2 have been identified by W. C. Prinz (Art. 127) in the manganese deposits near Philipsburg, Mont. The two zinc-bear- ing oxides—chalcophanite and hetaerolite—occur only as alteration products of primary rhodochrosite asso- ciated with sphalerite. They may, therefore, prove useful as guides to deeper ores of this kind. Studies in Colorado Studies by E. T. McKnight in the Rico district, Colorado, have shown that many of the lead—zinc de- posits are on the fringes of massive pyritic “blanket veins” that extend along limestone beds outward from their intersections with mineralizing fractures. The fractures themselves are obscure and displace the beds only slightly. A significant contribution to the problem of zoning of sulfide mineral deposits has been made by P. K. Sims (1960b) and Paul B. Barton, Jr., (Barton, Toul- min, and Sims, 1960) in their studies in the Central City district, Colorado. The district—wide Pattern is interpreted as having originated from cooling of solu— tions from initial temperatures of about 600° C to about 200° C as they moved upward and outward. As re- flected by systematic changes in the composition of sphalerite, the chemical potential of sulfur dropped slowly during cooling and the more sulfur-rich mineral assemblages were deposited peripherally. Presumably, the chemical potential of sulfur changed through homogeneous reactions in the ore fluid, for there is no indication of extensive reaction with wall rock at this stage. GEOLOGICAL SURVEY RESEARCH 19 6 1—SYNOPSIS OF RESULTS Base and precious metals were deposited in part concurrently with the widespread propylitic alteration throughout and beyond the Silverton caldera, north- western San Juan Mountains, Colo. The paragenesis of ore and gangue minerals, and the structural evolu- tion of veins and chimneys in the district as determined by W. S. Burbank and R. G. Luedke (Art. 149), indi- cate that two kinds of primitive ore solutions were involved, one of which was richer in sulfur compounds than the other. The observed differences in mineral assemblages and in paragenesis are due to mixing of these solutions with solutions containing end products of rock alteration and with oxygenated meteoric waters. In much of the Leadville area, Colorado, the bedrock is deeply buried beneath unconsolidated deposits. Studies of these deposits and related late Cenozoic events by Ogden Tweto (Art. 56) have shown that the bedrock surface is very irregular as a result of repeated canyon cutting by streams and glaciers, and of repeated movements on young faults. The rough topography of the bedrock—not previously recognized—accounts for the pattern of some ore deposits, and also affected the pattern of oxidation of the ores. East Tintic silver-lead district, Utah Continued exploration by the Bear Creek Mining Company has extended the known limits of the Burgin ore body, which was discovered through application of principles developed by Survey personnel, as de- scribed by T. S. Lovering and H. T. Morris (1960). The extension of the buried thrust fault zone in which the deposit lies is being traced as part of a new pro- gram of surface and subsurface exploration. The success of this venture has stimulated new exploration to the southeast by the Tintic Utah Mining Company. Central mining district, New Mexico A complex history of intrusions, domal uplift, sub- sidence, volcanic activity, renewed intrusion, and fault- ing between Late Cretaceous and early Miocene time has been worked out in the Central mining district, New Mexico, by W. R. Jones, R. M. Hernon, and W. P. Pratt (Art. 150). About 30 varieties of intrusive rocks in the district can be assigned to four age groups within this time interval, and the youngest group can itself be divided into five subgroups on the basis of cross-cutting relationships. After the first group of intrusions had domed Upper Cretaceous and older sediments, differential subsidence led to formation of the Santa Rita horst. Some volcanism and additional faulting followed a period of erosion, and then three discordant plutons were forcibly injected; these plu- tons in turn were cut by the earliest dikes of the HEAVY METALS youngest intrusive group before any significant min- eralization occurred. Extensive ore deposits of several types formed in carbonate sedimentary rocks, the in- trusive rocks, and along major faults before dikes of the second subgroup were injected. Early Miocene volcanic rocks around the edges of the horst provide an upper time limit to the events described. Lead, zinc, and related ores of the Central and Eastern States Several independent but related studies have con- tributed new data on the origin of Mississippi Valley- type ores. W. S. West and Harry Klemic (Art. 296) present evidence that in the Belmont and Calamine quadrangles, Wisconsin, solution-thinning of lime- stone beds by meteoric waters initiated slumping and brecciation that prepared the sites for later mineraliza— tion. The ore-depositing solutions probably were of nonmeteoric origin. Helmuth Wedow is applying high—speed computer techniques to data from drill holes in the eastern Ten- nessee zinc district to test the correlation between oc- currence of sphalerite and variation in thickness of limestone units, which are believed to be thinned locally by solution. As records for more than 1 million feet of drilling are available, successful adaptation of computer methods to this problem will greatly reduce the labor involved and may point the way to applica- tion of this technique elsewhere. In the Mascot-Jefferson City area, Tennessee, the zinc deposits are apparently localized by major struc— tural features rather than by features related to thin- ning. A. L. Brokaw (1960) points out that the deposits are restricted to a zone of elongate domes and bent folds that lies transverse to the regional trend of Appalachian folds and overthrusts. A. V. Heyl, Jr., and M. R. Brock (Art. 294) relate the fluorspar—zinc deposits of the Kentucky-Illinois district to doming and fractures at the intersection of two major fault zones. One of these is the zone of strong shears that connects the Central Kentucky, Ken- tucky-Illinois and Southeast Missouri districts. An ex- plosion breccia at Hicks Dome in the northern part of the Kentucky-Illinois district has been dated as Cre— taceous 011 the basis of an age determination made by T. E. Stern on a thorium-rich monazite specimen taken from the mineralized breccia. The monazite is of a type which, according to W. C. Overstreet, is characteristic of extremely deep-seated intrusions. Work by W. E. Hall and Irving Friedman on stable isotopes in fluid inclusions in ores from the Kentucky- Illinois and Wisconsin districts suggests that the mineralizing solutions in the two districts changed in the same way during the course of ore deposition. Highly concentrated deuterium-rich brines in early A—3 minerals give way to less concentrated and relatively deuterium-poor fluids in younger ore and gangue min- erals. The change in chemistry and isotopic composi- tion of the fluids in the inclusions is believed to be due to mixing of waters of different origins. (See p. A—96.) Gold in California Mapping by J. P. Albers and others (Art. 147) in the French Gulch-Deadwood gold mining district in northern California, done in cooperation with the Cali- fornia Division of Mines, has shown that the lodes are quartz veins along steep faults in the Bragdon forma- tion and along a thrust contact between the Bragdon and underlying Copley greenstone- Seven mines along an east-west zone 9 miles long and less than a mile wide have yielded most of the 835,000 ounces of gold thus far obtained from the district. COMMODITY STUDIES In a review of gold—producing districts in the United States, A. H. Koschmann and M. H. Bergendahl (1961) have found that there are 504 districts in which total gold production has exceeded 10,000 ounces. Gold production in the United States reached an all- time high of 4,869,949 ounces in 1940. Since then it has declined to less than half this figure. Reserves are sufficient to support production at the rate of 1940, but marked changes in the economics of gold mining would be necessary to achieve such an output. Germanium has in the past been recovered mainly as a byproduct of zinc smelters. New analyses and a re— view of the literature by Michael Fleischer (Art. 110) show that copper sulfides, especially enargite, com- monly contain higher concentrations of germanium than does sphalerite. The possibility of recovering germanium commercially from byproducts of certain copper smelters warrants attention. TOPICAL STUDIES Heavy metals and trace elements in black shales and phos- phorites Samples collected by D. F. Davidson and H. W. Lakin (Art. 267) from six selected shale units in the western United States contain metal in amounts com— parable to those of shale units considered “ore” in other parts of the world. The samples are from the so-called “vanadiferous shale” in the Permian Phosphoria for- mation of western Wyoming and southeastern Idaho; the Comus formation of Ordovician age, near Gol- conda, Nev.; an unnamed lower Paleozoic formation in the Fish Creek range, near Eureka, Nev.; the Missis- sippian Deseret limestone at Mercur Dome, near Tintic, Utah; the Chainman shale of Mississippian age near Ely, Nev.; and the Pennsylvanian Minnelusa forma- tion in the southern Black Hills, S. Dak. All the shale A—4 units are black, and all are rich in organic material. They contain as much as 1.5 percent zinc, 5 percent vanadium, 1 to 2 percent nickel, 0.7 percent selenium, and lesser amounts of other metals. Similarly, J. D. Love (Art. 250) has found that the Meade Peak phosphatic shale member of the Phos— phoria formation near Afton, Wyo., contains as much as 2.5 percent V205, 1.3 percent ZnO, 1 percent Ti02, 0.5 percent Cr203, 0.3 percent NiO, 0.1 percent M003, and 0.068 percent Se. A 3-foot bed averages 0.9 percent V205 and contains 45 million tons of rock to a depth of 500 feet below the level of major streams. Analyses by R. A. Gulbrandsen (1960a, b) of 60 samples of phosphorites from the Phosphoria forma- tion show the following approximate modal and maxi- mum contents, respectively, of minor elements: Cr, 0.1 and 0.3 percent; La, Ni, Sr, V, Y, 0.03 and 0.1 percent; Ba, Cd, Cu, Mn, Mo, Nd, Zn, 0.01 and 0.03 percent; As, U, 0.005 and 0.02 percent; B, Zr, 0.003 and 0.01 percent; Se, 0.001 and 0.007 percent; Ag, Co, Pb, Sb, Sc, Yb, 0.001 and 0.003 percent; Ga, <0.001 and 0.001 percent; Be, 0.00005 and 0.0003 percent. He finds that the high chromium phosphorites are likely to contain greater than average amounts of other minor elements and organic matter. He also finds that Sr, U, and the rare earths are enriched in the apatite component of the rock, whereas Ag, Zn, V, Cr, Mo, As, Sb, and Se are enriched in the organic component. LIGHT METALS AND INDUSTRIAL MINERALS DISTRICT AND REGIONAL STUDIES Beryllium at Spor Mountain, Utah In mineralogic studies of beryllium ore from Spor Mountain, Utah, E. J. Young and W. R. Griffitts have found that bertrandite is the main ore mineral and that associated introduced minerals are fluorite, opal (B—cristobalite) , montmorillonite, and quartz. The ore is very fine grained and many of the bertrandite particles are smaller than one micron, which may make beneficiation diflicult. The distribution of beryllium in nodules and hand specimens of the Spor Mountain ore was determined by means of a contact printing method devised by W. R. Griflitts and L. E. Patten (Art. 286). Beryllium in the Mount Wheeler area, White Pine County, Nevada Work in the Mount Wheeler area, Nevada, by D. H. Whitebread and D. E. Lee (Art. 193) has shown that the so—called Wheeler limestone c’ontains beryllium minerals in an area 1 mile north of the Mount Wheeler mine as well as at the mine itself. This limestone unit, which is within 70 feet of the base of the Pioche shale, of Cambrian age, may be either a single continuous bed GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS or a series of lenses. The beryllium minerals at the mine and at the new occurrences are associated with quartz veinlets that cut the limestone. The new occur— rences are near a quartz monzonite stock that is the in- ferred source of the beryllium. Veinlets of quartz in the so-called Wheeler limestone probably will serve as the most useful guide in further search for beryllium minerals in this area. Beryllium in the Lake George district, Colorado Beryllium deposits in the Lake George district, Colo- rado, described previously by Hawley, Sharp and Grriflitts,2 and by Sharp and Hawley3 are associated with pink biotite granite related to the Pikes Peak granite of the Colorado Front Range. The largest known deposit, at the Boomer mine, is closely associ— ated with a small granite stock that was intruded into schist, gneiss, and pegmatite. Other such deposits may yet be found in association with obscure or buried stocks in the part of the area consisting mainly of metamor- phic rocks. Possible surface guides to such stocks are concentrations of aplitic dikes, rocks altered to quartz— muscovite-fluorite greisen, and large premineralization faults that appear to have guided emplacement of granites. Beryllium deposits in the areas of metamorphic rocks contain visible crystals of beryl; deposits in the gran- ites contain inconspicuous bertrandite with or without beryl. The beryllium-bearing mineral euclase has been found in small amounts at the Boomer and Red- skin mines, and may occur other places in the area in minor amounts. This seems to be the first discovery of euclase in North America. Pegmatites of the Spruce Pine district, North Carolina F. G. Lesure infers that deformed minerals and gneissic or cataclastic structures that are common in pegmatites of the Spruce Pine district may be the result of synorogenic emplacement of the pegmatites, and that the late faulting and shearing may have formed during movement of the Blue Ridge thrust sheet (Bryant and Reed, 1960). Vermiculite deposits in South Carolina W. C. Overstreet and Henry Bell have found that the zircon-rich vermiculite deposits of the South Caro- lina Piedmont are altered parts of the wall zones of syenite pegmatite dikes. These wall zones are as much 2 Hawley, C. C., Sharp, W. N.. and Griflitts, W. R., 1960, Preminerali- zation faulting in the Lake George area, Park County, Colorado, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400—B, p. B71—B73. 3 Sharp, W. N., and Hawley. C. C., 1960, Bertrandite—bearing greisen, a new beryllium ore in the Lake George district, Colorado, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400-B, p. B73—B74. LIGHT METALS AND as 20 feet thick. The vermiculite is a product of the alteration of biotite, which is an abundant primary constituent of the pegmatite. The biotite and vermiculite are commonly in pegma- tites that cut gabbro or amphibolite, but also occur where the dikes cut felsic rocks. Thus it seems certain that composition of the wall rock is not as important in the origin of vermiculite deposits as was previously supposed. Fluorspar in the Browns Canyon district, Salida, Colorado In a cooperative project with the Colorado State Metal Mining Fund, R. E. Van Alstine has mapped ‘ the geology of the Poncha Springs NE quadrangle, Colorado, which covers the main part of the Browns Canyon fluorspar district in Chaifl'ee County. The fluorspar deposits occur chiefly along steep northwest- trending normal faults in Tertiary volcanic rocks and Precambrian granite and gneiss. The volcanic rocks are older than lower Pliocene sediments. One of the faults is at least 3.5 miles long and contains ore almost continuously for about 2,600 feet. The maximum thick- ness of the fissure veins is about 40 feet, and the Can content ranges from about 25 to 75 percent. The ore consists principally of fine-grained fluorite and quartz, mutually interspersed or interlayered. Minor con- stituents include calcite, barite, pyrite, marcasite, opal, montmorillonite, kaolin, a stilbite-like zeolite, manga- nese oxides (cryptomel‘ane, pyrolusite, and manganite), hematite, and limonite. The wall rocks have been altered locally, either by the introduction of fluorite and silica, or by the development of chlorite or clay minerals. Phosphate deposits in the Southeastern States During the course of a detailed study of the phos- phate deposits in the land-pebble district of Florida, J. B. Cathcart has found an explanation for the northern and eastern limits of phosphate occurrence. Primary phosphate in the land-pebble district occurs in the Hawthorn formation of middle Miocene age. The minable deposits, however, are in residuum at the top of the Hawthorn formation and in the lower part of the overlying Bone Valley formation, of Pliocene age. The reworking and concentration of weathered and disintegrated phosphatic material took place in a sea that reached its northern limit on the flank of a hitherto undescribed positive structural element, called the Hillsborough high, which is related to the much larger Ocala uplift. The Hillsborough high was rising as the Hawthorn formation was being deposited, and it re- mained as a positive area during the early part of the Pliocene. There are no minable phosphate deposits north of the high. The eastern margin of the district 608400 0——61_——2 INDUSTRIAL MINERALS A—5 is a sharp line at the edge of a ridge that acted as a barrier to the sea during deposition of the lower part of the Bone Valley formation. The lower unit does not extend east of this ridge, and, accordingly, economic phosphate deposits do not occur there. J. B. Cathcart and F. W. Osterwald have concluded that all economic phosphate deposits in the Southeast— ern States are similar to the Florida deposits in origin and in tectonic setting, although they occur in rocks of Ordovician and Pennsylvanian ages, in addition to rocks of Tertiary age. They are all derived mainly by the weathering and reworking of sandy and clayey phosphatic limestone beds that were deposited on the rising flanks of foreland domes, far from the sources of elastic material. The phosphate was deposited in a rather narrow depth zone, and as the domes rose, phos- phatic limestone was deposited at a progressively greater distance from the " crest of these structures. Limestone beds of equivalent age but in a different tectonic setting are not phosphatic. Clay in Maryland Bloating clays from Maryland, described previously by M. M. Knechtel and J. W. Hosterman,4 have been subjected to rotary-kiln firing tests by H. P. Hamlin of the U.S. Bureau of Mines. These clays were sampled during an investigation conducted in coopera- tion with the Maryland Department of Geology, Mines, and Water Resources, and with the U.S. Bureau of Mines. The material tested came from exposures of the St. Marys formation, of Miocene age, at three local- ities along the shore of Chesapeake Bay in Calvert County, Md. The tests indicate that the clay in each of these places is suitable for the manufacture of ex- panded lightweight aggregate. Enough of this bloat— ing clay may be available in southern Maryland, and perhaps also in other parts of the Atlantic Coastal Plain, to supply a new industry. Clay in Kentucky In a cooperative study with the Kentucky Geological Survey, J. W. Hosterman and S. H. Patterson (Art. 120) have found that refractory clay of the Lower Pennsylvanian Olive Hill clay bed is exposed in a belt approximately 15 miles wide that extends southwest- erly 55 miles from the Ohio River near Portsmouth, Ohio, to Frenchburg, Ky., and may extend 50 miles farther south to Laurel County, Ky. Boehmite, a bauxite mineral identified recently by X-ray, occurs locally as nodules in the clay. Previously, bauxite minerals had not been known in the Olive Hill clay 4Knechtel, M. M., and Hosterman, J. W., 1960, Bloating clay in Miocene strata of Maryland, New Jersey, and Virginia, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400—3, p. B59—B62. A—6 bed, although they are common in the Lower Pennsyl- vanian Mercer clay of central Pennsylvania. Borate in California During the course of an investigation of the Furnace Creek borate area, carried on in cooperation with the California Division of Mines, J. F. McAllister has found that weathering at the surface of the borate de- posits tends to produce minerals relatively high in B203. Some of these minerals have not been described previously, and others are exceedingly rare. One of the new minerals is nobleite (CaO-3B203-4H20), described by R. C. Erd, J. F. McAllister, and A. C. Vlisidis. McAllister (Art. 129) has identified sborgite (Na20-5B203-10H20), reported otherwise only from Italy; and Erd and others (Art. 255) have identified tunellite (SrO-3B203 '4H20) , found previously only at Boron, Calif. The sborgite was found in an efliores- cence of thenardite and halite on outcrops of somewhat saline lake beds in the Furnace Creek formation. Sborgite forms in the present environment, as demon- strated by a few stalactites of sborgite, thenardite, and some halite, in a mine. Pumice and pozzolan deposits in the Lesser Antilles Very large deposits of pumiceous material are now known to occur on the Caribbean islands of Dominica, Martinique, and St. Eustatius. As described by E. B. Eckel (1960b), the deposits contain both lump pumice, which is used chiefly for lightweight building blocks, and fine-grained pumicite, which has excellent pozzo- lanic properties. The deposits are Within easy shipping distance of many potential markets in Puerto Rico and elsewhere in the Caribbean, as well as along the east and gulf coasts of the United States. They could pro- vide the basis of an important local industry. COMMODITY AND TOPICAL STUDIES Beryllium W. R. Grifiitts and E. F. Cooley (Art. 109) have investigated the beryllium content of cordierite, which is structurally similar to beryl and therefore might be expected (in places) to contain noteworthy amounts of beryllium. Specimens of cordierite from pegmatite and from quartz veins in pegmatite districts contained a maximum of 0.2 percent Be, which is high for a nominally nonberyllian mineral but far lower than that of beryl. Research is continuing in an effort to improve and extend instrumental techniques in which the gam- ma-neutron reaction is used to detect beryllium. A drill-hole logger using this principle has been success- fully field tested by W. W. Vaughn and associates. GEOLOGICAL SURVEY RESEARCH lQfil—SYNOPSIS OF RESULTS Potash Three classes of potash deposits have been recognized by C. L. Jones during the course of studies in New Mex- ico: (a) widespread polyhalite deposits formed by replacement of anhydrite beds; (b) sylvite and lang— beinite, associated with other potassium, magnesium, and sodium salts, formed in halite beds; and (c) small monomineralic lenses and veins of sylvite, polyhalite, and carnallite that out various rocks. Of the three types of deposits, only the second has been mined. Stratigraphic and petrographic studies of evaporite deposits in the Paradox Basin, Utah, by R. J. Hite (Art. 337), in addition to the work in New Mexico, indicate that deposition of the evaporites and asso- ciated sediments was cyclic, or even doubly cyclic. Deposition under regressive conditions is recorded by the downward sequence of halite-anhydrite-carbonate, and under transgressive conditions by the reverse of this sequence. Deposition in probable response to sea- sonal variations in the salinity of the water is recorded by thick units Of finely laminated, varvelike rocks. Reorganization of materials since deposition has greatly complicated the original relations. RADIOACTIVE MATERIALS DISTRICT AND REGIONAL STUDIES Colorado Plateau Botryoidal coflinite in a specimen from the Woodrow mine near Laguna, N. Mex., has been Observed by R. H. Moench to be interbanded with pyrite, cobaltite, and barite and to contain small amounts of galena, wurtzite, cobaltite, and a trace of chalcopyrite. These textural relations suggest that the uranium and sulfide minerals were formed at the same time. From study Of uranium-vanadium and copper de- posits in the Lisbon Valley area of Utah and Colorado, G. W. Weir and W. P. Puffett (1960c) have concluded that the two kinds of deposits were formed by the same or similar low-temperature hypogene solutions, be- cause: (a) copper minerals occur in many uranium- vanadium deposits, (b) uranium and vanadium min- erals occur in some copper deposits, (0) both kinds of deposits occur in tabular bodies in sedimentary rocks, and (d) the copper deposits are near faults. Because regional variations of M0, As, Co, Ni, Zn, and Se in uranium deposits in the Salt Wash member of the Morrison formation correspond with differences in tufl' content of the member, A. T. Miesch (Art. 123) concludes that these elements were derived from the tufi'aceous component of the member and collected into deposits by solute diffusion. Another group of ele— FUELS ments, Cu, Ag, much of the Pb, V, U, and some Zn came from external sources and were introduced later by solution flow. Although all samples of identifiable fossil wood from several uranium deposits in the Colorado Plateau re- gion are species of araucarian conifers, the uranium content difi'ers " so markedly among samples of one species from a single deposit that R. A. Scott (Art. 55) concludes that the kind of wood in the deposits was not an important control in localizing ore. Shirley basin, Wyoming E. N. Harshman (Art. 148) has found that the major uranium deposits in the Shirley basin, Wyo., lie just west of a northwesterly trending ridge on the pre-Ter— tiary erosion surface upon which the ore-bearing Wind River formation accumulated. In Wind River time, streams transporting arkosic debris from granitic areas lying to the southwest were diverted parallel to the ridge. ReSultant physical and chemical conditions were favorable for the subsequent concentration of uranium in deposits parallel to and west of the ridge. Coastal plain, Texas Relatively recent discovery of hydrogen sulfide— bearing oil and gas in fields adjacent to faults and down dip from uranium deposits in Karnes and adjoining counties, Texas, has led D. H. Eargle and A. D. Weeks (Art. 295) to postulate that hydrogen sulfide seeping from those sources into overlying Tertiary rocks may have created reducing environments in which uranium was precipitated from alkaline ground water. Front Range, Colorado In study of primary black uranium ores in the Front Range, Colo., P. K. Sims, E. J. Young, and W. N. Sharp (Art. 2) have found that coffinite, previously thought to be rare in uranium vein deposits of the United States, is present in 6 veins of epithermal type and is an important ore mineral in at least 3 of these. Powderhorn district, Colorado In the Powderhorn district, Gunnison County, Colo., D. C. Hedlund and J. C. Olson (Art. 121) have found that thorium, niobium, and rare earths are concentrated in (a) veins bearing thorite and thorogummite, (b) dikes and plug-like bodies of carbonatite, where they are contained in pyrochlore, monazite, apatite, bastnaesite, and synchisite, (c) segregations of magne- tite-ilmenite-perovskite, and (d) trachyte dikes. TOPICAL STUDIES Epigenetic deposits of uranium in limestone Data on uranium deposits in northwestern New Mexico compiled by L. S. Hilpert (Art. 3) indicate that A—7 deposits in limestone are always of epigenetic origin; they occur in rocks of Permian and Triassic age de- formed by faulting, or in rock of Jurassic age (Todilto limestone) deformed by intraformational folding; and they are distributed in two different geologic provinces, the Colorado Plateau and the Basin and Range. Be- cause these deposits and others described in the geologic literature occur under rather diverse geologic condi- tions, he concludes that carbonate rocks are good hosts for epigenetic uranium deposits only where these rocks are deformed. Geology of uranium deposits in sandstone Review and analysis by W. I. Finch of the large amount of data on uranium deposits in sandstone in- dicate that about 98 percent of the pene-concordant deposits are in sandstone formed in continental sedi- mentary environments. The sandstone accumulated in closed or partly closed basins—mainly in areas bordering the stable interior platforms, and to a minor extent in postorogenic depressions, including some fault-block valleys. None of the sandstone accumulated in geosynclines. Uranium-bearing lignite, some uranium-bearing limestone, and uranium-bearing con- glomerate of Precambrian age had a similar sedimen- tary and tectonic setting. Continental rocks formed in such environments offer the best opportunities for find— ing new uranium-bearing deposits. - Source of monazite in some Australian placers In reviewing the literature concerning the geology of monazite, W. C. Over-street finds that detrital mona- zite on beaches fronting the South Pacific in Queens- land and New South Wales contains 6.6 i 0.5 percent thoria (Th0 2) as compared to only one-tenth to one- fifth that amount in monazite from stream placers in the tin fields of the highlands upstream from the coast. This marked difference suggests that monazite of the beaches cannot, as previously thought, have come from the same source rocks as that in the stream placers. The composition of the monazite on the beaches sug- gests that it was derived from plutonic gneiss bodies not now exposed. FUELS PETROLEUM AND NATURAL GAS Many studies carried on within the Survey contribute fundamental stratigraphic and geologic data that are used by those engaged in petroleum exploration. These studies are reported under regional headings, beginning on page A—9. COAL Coal studies by the US. Geological Survey include (a) geologic mapping and stratigraphic studies of A—8 specific coal fields; (b) appraisal of resources in in- dividual coal fields, States, or the whole nation; and (c) investigation of the petrography, composition, and structure of coal. Coal fields of the United States A new map of the coal fields of conterminous United States by James Trumbull (1959) shows, on a scale of 1: 5,000,000, the distribution of coal-bearing areas, in colors according to the rank of coal. Inset maps and diagrams show geologic ages of coal-bearing rocks, the basis of coal—rank determination, bituminous coal producing districts, cumulative coal production to January 1, 1959, and estimated original coal reserves, by States. Coal resources of Arkansas In a report prepared in cooperation with the Arkansas Geological and Conservation Commission, B. R. Haley (1960) estimates that the original reserves of low-volatile bituminous coal and semianthracite in Arkansas totaled 2,272 million tons. This estimate is 70 percent larger than that made by M. R. Campbell in 1908. Geology of specific coal fields Studies by W. C. Warren (1959) in the Birney- Broadus coal field in Rosebud and Powder River Counties, Mont., have shown that the field contains about 21.5 billion tons of subbituminous coal in beds 21/2 or more feet thick and within about 1,000 feet of the surface. Geologic investigations in the Livingston-Trail Creek coal field, Montana, by A. E. Roberts indicate that the field contains 226 million tons of coal. Analy— ses of 89 coal samples from the field indicate that the coal is of high-volatile bituminous rank. Spheroidal structures in coal Coal beds in the Vermejo formation of Cretaceous age and in the Raton formation of Cretaceous and Paleocene age in the Trinidad coal field, Colorado, ex- hibit two types of spheroidal structure. R. B. Johnson (Art. 153) believes that one type is the result of stresses due either to lateral movements or shrinkage during lithification; the other type seems to be the result of shrinkage caused by heat from nearby sills. OIL SHALE Studies of the oil shale in the Green River formation of Eocene age in the southeastern Uinta basin, Utah, by W. B. Cashion (Art. 154) indicate that an area of 690 square miles is underlain by an oil-shale sequence 15 to 370 feet thick. The sequence will yield about 15 gallons of oil per ton of rock and the potential oil re- serves of the area total about 53 billion barrels. GEOLOGICAL SURVEY RESEARCH lQGl—SYNOPSIS OF RESULTS Mapping by W. C. Culbertson in the Firehole basin 15-minute quadrangle, Wyoming, has demonstrated that a sequence 40 feet thick in the upper part of the Tipton shale member of the Green River formation is a persistent oil-rich unit underlying at least 500 square miles in and near the quadrangle. Assays of cores and outcrop samples indicate that the unit will yield 18 to 30 gallons of oil per ton of shale and that it contains at least 20 billion barrels of oil. WATER REGIONAL AND DISTRICT STUDIES Distribution and characteristics of streamflow The amount and variation of surface-water supplies in the United States is ascertained by means of a net- work of about 7,200 continuous-record stream-gaging stations. Of these about 2,800 are primary stations at which streamflow data are recorded continuously for long periods. About 1,400 are secondary stations that are operated for periods of 5 to 10 years and are moved from place to place as required. The remaining 3,000 stations serve miscellaneous needs for streamflow data. In addition, special information on low- or high-flow characteristics is obtained at about 5,000 partial-record station. Data from this network of stations are summarized and analyzed in areal studies of the availability of water supplies. For example, a study of water supplies of Kanawha County, W. Va., by W. L. Doll, B. M. Wilmoth, J r., and G. W. Whetstone (1960) resulted in the conclusion, based on the present rate of increase in water use, that enough water is available in the Kanawha River basin to supply needs for many years to come. In Puerto Rico, Ted Arnow and J. W. Crooks (1960) found that of 93 million gallons per day delivered to 76 urban and 860 rural areas, about 90 percent of the production was from surface—water sources. R. W. Pride and J. W. Crooks have concluded from a study of rainfall and streamflow records in Florida that the drought of 1954—56 was the most severe on record. In this 3-year period, deficiencies in annual rainfall ranged from 7 to 11 inches; and the average annual runoff from the State was only about 6 inches, as compared to the long-term average runoff of about 14 inches. Records of streamflow in Kansas analyzed by L. W. Furness (1960), show that, in general, the low flows decrease progressively westward except that in the Marais des Cygnes basin they are lower than regional values and in parts of south-central Kansas they are higher. On most streams in the western part of the State and in parts of the Marais des Cygnes and Neo— sho basins the discharge diminishes to zero every other WATER year on the average. On the South Fork Ninnescah River basin, where the flow is sustained better than elsewhere in Kansas, the annual minimum 7—day flow is as much as 0.06 cubic feet per second per square mile at average intervals of 2 years. Man’s activities may have a profound effect on streamflow. In a study of the effects of reforestation in four small areas in New York, W. J. Schneider and G. B. Ayer (1961) found through examination of streamflow records collected since 1952 that reforesta- tion had resulted in significant decreases in runoff. At the time of the study three of the areas had been partly (35 to 58 percent) reforested, mostly with species of pine and spruce. As a result, runoff from one stream was reduced 0.36 inch per hydrologic year and peak dis- charges during the dormant season were reduced by an average of 41 percent. Significant change in peak flows during the growing season could not be demonstrated. In a study of the effects of urbanization, A. O. Waananen (Art. 275) concludes that peak rates of runoff from areas of urban development may be 3 to 4 times greater than those from nearby undeveloped areas. WATER USE Water use in river basins of Southeastern United States The river basins of Southeastern United States cover an area of 86,543 square miles in parts of South Caro- lina, Georgia, Florida, and Alabama. Withdrawal of water in these basins totaled nearly 3,900 mgd (million gallons per day) during 1960 according to a study by K. A. MacKichan and J. C. Kammerer (1961). This amount is equivalent to 750 gallons per capita per day. The withdrawal was divided among several classes of users as follows: industry, 3,300 mgd; public supplies, 400 mgd; rural domestic and livestock, 110 mgd; and irrigation, 42 mgd. Of the total withdrawn, only 290 mgd was consumed. Water use by the Savannah River plant of the Atomic Energy Commission is not in- cluded. About 61 percent of the surface water and 94 percent of the ground water was withdrawn in the Coastal Plain part of the basins. The total withdrawal increased 31 percent between 1955 and 1960. Con- sumptive use probably increased at about the same rate. The use of saline water was almost three times as great in 1960 as in 1955. Copper industry About 330 mgd of water was used in 1955 in mining and manufacturing primary copper. About 70 percent was used in mining and concentrating ore and about 30 percent was used to reduce the concentrate to pri- mary copper. About 60 mgd, or 18 percent, of the water was used consumptively, and nearly all of the A—9 consumptive use occurred in the water-short areas of the West. On the average about 50 gallons of water is required to produce a pound of refined copper. Much of the water used in producing primary copper was of low quality. About 46 percent contained 1,000 ppm (parts per million) or more of dissolved solids. Median total dissolved solids in water used in mining and ore concentration average a little less than 400 ppm, and hardness (as CaCOa) a little more than 200 ppm. The corresponding median values for water used in smelting and refining average only half these amounts. Styrene, butadiene, and synthetic rubber industries The water requirements of the styrene, butadiene, and synthetic rubber industries totaled about 710 mgd in 1959, according to an analysis by C. N. Durfor. The intake of the individual industries was as follows: butadiene, 429 mgd; styrene, 158 mgd; special-purpose rubber, 94 mgd; and SBR (styrene-butadiene rubber), 29‘mgd. The butadiene industry consumed 4.5 percent of its intake, the styrene industry, 2.0 percent, the spe- cial—purpose rubber industry, 9.1 percent, and the SBR industry, 11 percent. Most of the water intake was used for cooling: buta- diene, 96 percent; styrene, 98 percent; special-purpose rubber, 90 percent; and SEE, 17 percent. Of the total intake, 64 percent of the water was salty. These waters, which were used only for once-through cooling, contained as much as 35,000 ppm of dissolved solids. Excluding these salty waters the maximum hardness of the intake water used for the production of buta- diene was 342 ppm; for styrene, 404 ppm; for SBR, 495 ppm; and for special-purpose synthetic rubber, 618 REGIONAL GEOLOGY AND HYDROLOGY In addition to the resource investigations described on the preceding pages, the Geological Survey is engaged in studies of broader scope aimed at an understanding of the geology and hydrology of the United States. Studies of the composition, structure, history, and origin of the rocks that compose the earth’s crust in the United States are carried out by regional geologic mapping, together with parallel studies in the fields of geophysics, geochemistry, stratigraphy, and paleon- tology. The preparation of general-purpose geologic maps and accompanying studies often provide the first clue to the location of new mineral districts, and they aid directly in the search for concealed deposits. They also provide background information for (a) apprais- ing the potential mineral, fuel, and water resources of various parts of the country, (b) selecting favorable sites for engineering works such as highways, dams, de- A—10 OUTHERN R0 cmrs AN PLAINS D 500 MILES GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS FIGURE 1.—Index map of conterminous United States showing boundaries of regions referred to on accompanying pages. fense tests, and homes, and (c) enhancing appreciation of scenic features and recreational areas. Studies of the quantity, quality, and availability of the Nation’s water resources are carried out in part through areal investigations of districts and drainage basins. In these studies hydrologic and related geo- logic variables are examined and recorded. These var- iables include sources of inflow, the movements of surface and ground water, the effects of various geologic materials on water movements and on compo— sition, the effects of water movements on rocks and sediments, and the disposition of water, including con- sumption, evaporation, transpiration, and outflow of both surface and ground waters. Such studies pro— vide the basic data needed for an intelligent appraisal of the Nation’s water resources; they make it possible to predict the effects of man’s activities on water regi- men, and they aid in solving local water problems. Some of the major results of regional geologic and hydrologic work during the fiscal year 1961 are de- scribed in the following pages. These results are clas- sified by region as shown in part on figure 1. SYNTHESIS OF GEOLOGIC DATA ON MAPS 0]." LARGE REGIONS The preparation of maps of national or larger scope is a minor but very important function of the Geo— logical Survey. In compiling such maps the Survey depends largely on data gathered as part of local and regional mapping programs, supplemented by data generously provided by State surveys, private com- panies, and universities. The Survey also collaborates with national and international scientific societies in preparing, and sometimes publishing, maps of this type. Maps published or completed during the ‘year are described under separate headings below. Collabo- rative maps in progress include : 1. Geologic map of North America, scale 1: 5,000,000. This map, which is nearly completed, is being com- piled by a committee of the Geological Society of America, E. N. Goddard, University of Michigan, chairman. 2. Basement rock map of North America from 20° to 60° N. latitude, scale 1 : 5,000,000. This map has been compiled by a committee of the American Associa- SYNTHESIS OF GEOLOGLC DATA tion of Petroleum Geologists, P. T. Flawn, Univer- sity of Texas, Bureau of Economic Geology, chair- man. 3. Absolute gravity map of the United States, scale 112,500,000. This map has been compiled by the American Geophysical Union Committee for Geo- physical and Geological Study of the Continents, G. P. Woollard, University of Wisconsin, chairman. 4. Tectonic map of North America. This map, being compiled under the direction of P. B. King, is being prepared for the Subcommission for the Tectonic Map of the World, International Geological Con- gress. Mineral distribution maps Mineral distribution maps of conterminous United States are being compiled under the direction of P. W. Guild, T. P. Thayer, and W. L. Newman. Occurrences of 22 mineral commodities throughout the 48 conterminous States are shown on a series of maps completed thus far. About half of the com- modities are heavy metals and the remainder are light metals, industrial minerals, or radioactive materials. Maps of about 12 additional commodities are in various stages of preparation. The original maps are on trans- parent film on a scale of 1 : 2,500,000, designed as over- lays for the geologic and tectonic maps of conterminous United States. They will be published on paper at a scale of 1: 3,168,000, accompanied by short texts, locality indexes, and bibliographic references. Through cooperation of agencies of the Canadian and Mexican governments the series of distribution maps will in- clude mineral occurrences throughout North America as part of the general program of the Subcommission for the Metallogenic Map of the World, International Geological Congress. Tectonic map of the United States A new tectonic map of the conterminous United States, on a scale of 1: 2,500,000, will be released during the coming fiscal year. The map, prepared as a joint undertaking of the American Association of Petroleum Geologists and the Geological Survey under the direc- tion of G. V. Cohee, is a complete revision of the tectonic map published by the Association in 1944. By providing a geologic framework for delineating old and recognizing new mineral provinces, the tectonic map is of special value in the search for petro- leum, natural gas, and ore deposits. The map also has great scientific value as a tool in the interpretation of the structural history of the United States. Paleotectonic maps of the Permian system The long-term program to produce paleotectonic map folios of national scope for each of the geologic ON MAPS 0F LARGE REGIONS A—11 systems is continuing. The folio for the Permian sys- tem, largely completed in 1960, is being readied for publication; work has been started on a folio for the Pennsylvanian system. Interpretive maps prepared for each of several ma- jor subdivisions of the Permian system show the devel— opment of major tectonic elements in much of the central part of the continent. Tectonism was still active very early in Permian time, following the intensive activity in many areas near the end of the Pennsylvanian period. Numerous basins of deposition (some topographically deep) were separated from adjacent basins by highlands, which contributed detritus to the basins. The longest landmasses, including the ancestral Rocky Mountains and the central Nevada ridge, trended northeasterly, but many shorter landmasses, such as the ancestral Wichita-Arbuckle and Uncompahgre uplifts, were alined northwesterly. Many small positive areas formed hills projecting above areas of deposition. Relative tectonic stability characterized the second subdivision of the Permian system, composed largely of rocks of Leonard age. Many of the earlier positive areas had been reduced by erosion and buried by sedi— ments. Widespread regional sinking or a eustatio rise of sea level resulted in the accumulation of widespread blankets of sediments in basins of deposition that were far more extensive than those in very early Permian time. Noteworthy changes also included the develop- ment of a marine connection in Wyoming between the lordilleran geosyncline and the northern Midcontinent region, and in Arizona between the Cordilleran and the Sonoran geosynclines. The central part of the continent in the latter part of Permian time was even more stable. Positive areas in the northern part of the Western Interior were further reduced in size and prominence, and deposition was more widespread. In the Southwest, however, an ex- tensive area in Arizona and western New Mexico was emergent, although probably not very high. The sup— ply of detritus in most of the Midcontinent region exceeded the amount that. could be accommodated by regional downwarping, so many of the Permian basins were filled. Pleistocene lakes in western conterminous United States A new map of the western conterminous United States, prepared by J. H. F eth (Art. 47), shoWS the maximum known or inferred extent of Pleistocene lakes. Comparison of this map with reported lacus- trine deposits of Oligocene, Miocene, and Pliocene ages suggests that the general area of occurrence of the Pleistocene lakes was a little west and southwest of the area of occurrence of the older lakes. A—12 NEW ENGLAND AND EASTERN NEW YORK Geologic mapping, geophysical and geochemical sur- veys, and water resources investigations in New Eng- land and eastern New York are carried on largely through cooperative agreements with the various States. Some of the results of this work are summa- rized below. The results of geochemical exploration in New England are described on page A—95. Regional geologic mapping in Maine Preliminary studies by Andrew Griscom on the petrology of a mafic intrusive complex in the Stratton quadrangle show that the lower, layered half of the intrusion contains about 12,000 feet of interlayered norite, anorthosite (with rare spinel), pyroxenite, and dunite, and that the upper, nonlayered portion grades upward from norite into biotite diorite. E. V. Post has tentatively correlated rocks in The Forks quadrangle with lithologically similar rocks in the Stratton quadrangle, and in the Second Lake quad— rangle, New Hampshire-Maine. The latter correla- tion, in turn, suggests a correlation with the “Arnold River Complex” of Ordovician age in Quebec. The “ribbon rock” (a limestone with layers of slate) that underlies much of eastern Aroostook County was generally believed to be of Silurian age, but grapto- lites recently discovered by Louis Pavlides date it as Middle Ordovician (Trenton). Fossiliferous tufl' from the Shin Pond area studied by R. B. Neuman has yielded brachiopods, trilobites, bryozoans, gastropods, and echinoderms of probable Early Ordovician (Are— nig) age. Many of the species are new and the as— semblage as a whole has European affinities. Neuman and W. B. N. Berry have recognized the European aspect of faunas in rocks that span a considerable part of the Ordovician in this region. As the result of recent geologic mapping in west- central Maine and northern New Hampshire, A. L. Albee (Art. 168) suggests that the Taconic orogeny in this area involved major deformation and meta- morphism rather than just a tilting of the older rocks. Regional geologic mapping in Vermont The tectonic fabric of north-central Vermont has been analyzed by W. M. Cady as the first phase of a study of orogenic movements. The B-axis elements of an earlier fabric approach a right angle to the B—axes of the folds of the later Green Mountain north-north- east trending anticlinorium. Regional geologic mapping in Massachusetts and Rhode Island R. F. Novotny (Art. 311) has identified a major un- conformity as the base of the Pennsylvanian Worcester formation in east-central Massachusetts. The under- lying strata may be Silurian, as suggested by strati— GEOLOGICAL SURVEY RESEARCH lQBl—SYNOPSIS OF RESULTS graphic continuity with units in Maine and New Hampshire. A major fault marked by silicified and brecciated zones has been mapped for a distance of 25 miles in east-central Massachusetts and southern New Hampshire and may continue southward to the Vicinity of the Worcester “coal” mine. Recent mapping in the Concord quadrangle by N. P. Cuppels (Art. 310) has revealed a northeast—trending fault zone at least 25 miles long. The fault zone crosses the southeastern part of the quadrangle, is younger than the Andover granite of Carboniferous age, and may be genetically related to the Northern Boundary fault of the Boston basin. A striking example of frost-wedged bedrock has been discovered by Carl Kotefl' (Art. 170) at a locality north of New Bedford, in southeastern Massachusetts during mapping of the Assawompset Pond quadrangle. A knob of porphyritic granite that protrudes about 25 feet above the surrounding glacial deposits contains open- ings as much as 3 feet wide and 10 feet deep, developed along major joints. The joint blocks have been moved laterally over a gently dipping joint plane by frost wedging, presumably in a periglacial climate. Marine sediments as much as 50 feet above present sea level are of late glacial age, according to work by R. N. Oldale (Art. 171) in the Salem quadrangle along the northeast coast of Massachusetts. The sediments were deposited when glacial ice stood nearby, as pro- glacial outwash is interbedded with and in part overlies the marine sediments. Sand dunes as much as 50 feet high and 8,400 feet long have been mapped in the Springfield South quadrangle by Joseph H. Hartshorn. The dunes are both bow-shaped and longitudinal. Their bedding dips consistently 7 to 12 degrees south, indicating winds primarily from the north, although the forms of some bow-shaped dunes indicate a com- ponent from the northwest. Regional geologic mapping in Connecticut A narrow stratigraphic zone in the granitic gneiss of southeastern Connecticut is characterized by keilhauite, an aluminum-, iron-, and rare-earth—bearing variety of sphene, according to Richard Goldsmith, G. L. Snyder, and Nancy M. Conklin (Art. 399). Keilhauite also occurs in rocks in Rhode Island now called the Scituate granite gneiss, and may be a useful stratigraphic marker in the gneisses of southern New England. According to Richard Goldsmith (Art. 169), a dis- tinctive aegerine-augite granite and associated rocks identify refolded isoclinal folds in the granitic gneisses and high-grade metasedimentary and metavolcanic rocks of southeastern Connecticut. The Hunts Brook syncline, an isoclinal syncline near New London, has been tightly refolded, possibly as a result of deforma- NEW ENGLAND AND EASTERN NEW YORK tion that produced the generally westward-trending low-angle Honey Hill fault. G. L. Snyder has recognized three periods of metamorphism in the rocks of the Norwich and Fitch- ville quadrangles: (a) regional dynamo-thermal metamorphism, either as a single continuous process or as a series of episodes between 530 and 280 million years ago; (b) dynamic metamorphism, progressively more localized along certain zones of active faulting; and (c) alteration or retrograde metamorphism that resulted in the hydration of sillimanite-containing schists. The Waterbury gneiss has been divided by C. E. Fritts into two main metasedimentary units and at least two felsic metaigneous units. These rocks form the core of a dome. A thinly banded kyanite-bearing paragneiss that occurs east of Waterbury, Conn, con- tains as much as 54 percent kyanite and averages 9 percent, as judged from analyses of 29 samples. A large recessional moraine about 8 miles north of Long Island Sound near New London has been identified by Richard Goldsmith (1960a) and named the Ledyard moraine. The moraine extends east-north- eastward discontinuously for at least 13 miles, and marks a temporary halt in the retreat of ice from the moraines of Long Island and southern Rhode Island. A similar moraine found by R. B. Colton farther north near Windsorville, marks another previously un- recognized stand of the retreating ice. Geophysical surveys Gravity measurements by M. F. Kane in west—central Maine have delineated areas of mafic and felsic intru- sive rocks in a dominantly sedimentary terrain. Detailed gravity profiles over exposed or near-surface intrusive bodies have given considerable information on their size and shape. Both gravity anomalies and density measurements show that the sedimentary rocks are, in general, intermediate in density between the mafic and felsic rocks. In the Island Falls quadrangle, Maine, electro- magnetic techniques have been used by F. C. Frisch— knecht and E. B. Ekren to map the bedrock below a concealing cover of glacial drift. In the northwest and central parts of the quadrangle, zones of conductive black slate are common in the sequence of concealed rock, which is of probable Cambrian and Ordovician ages. These slate zones can be distinguished electro- magnetically from younger volcanic rocks in the north- west part of the quadrangle. In the central part the conductive zones occur in relatively narrow belts that are continuous for many miles. The conductive zones converge northeastward. Pronounced magnetic highs over the five ring dikes A—13 or stocks of the White Mountain plutonic—volcanic series in New Hampshire have been found by R. S. Bromery. Samples of the ring—dike rocks are being examined by Andrew Griscom and the data used to determine the structure of the ring complexes. Within the ring-dike area, the Moat volcanics and the Littleton formation (schist and gneiss) are magnetically low. Aero- magnetic data show that the Conway granite Within the ring-dike area is magnetically high, but that the Conway granite of the White Mountain batholith is magnetically low. Seismic work on Block Island, Rhode Island, by C. R. Tuttle and W. B. Allen (Art. 240) indicates that a low-velocity zone of Pleistocene deposits is underlain successively by unconsolidated deposits, semiconsoli- dated deposits, and, at 1,088 feet below sea level, by crystalline rocks. The unconsolidated deposits are probably of Cretaceous age, the semiconsolidated de- posits of Cretaceous or Triassic( ?) age, and the crystalline rocks of Paleozoic age or older. A study by Anna J espersen of the results of an aero- magnetic survey of the Greenwood Lake and Sloats— burg quadrangles, New York-New Jersey, indicates that the steepest magnetic gradients and the highest magnetic susceptibilities are associated with Precam- brian metasedimentary amphibolite and pyroxene amphibolite, the principal host rocks of the magnetite deposits in the Sterling Lake, N.Y.-Ringwood, N.J., area. The next two lower orders of magnetic sus- ceptibility seem to be associated With quartz-oligoclase gneiss and hornblende granite, respectively. Economic studies Slate that has been quarried at about 25 places in the Greenville and Sebac Lake quadrangles, Maine, occurs in a sequence of interbedded dark-gray slate, siltstone, and fine—grained sandstone of probably Early Devonian age, according to geologic mapping by G. H. Espenshade (Art. 152). Slaty cleavage is well devel- oped only where sandstone is interbedded with the slate. A large sample of slate with very poor cleavage was processed in the rotary kiln by the Bureau of Mines, and yielded lightweight aggregate of good qual- ity from which satisfactory lightweight concrete was made. A new copper vein at the upper contact of green- stone with schist of the Ottauquechee formation, ex- posed in roadcuts of the Waterbury Interchange on the new interstate highway to Montpelier, Vt., was sampled by L. R. Page and assayed 3 percent copper over a width of 44 inches. Precambrian magnetite deposits, interpreted by B. F. Leonard and A. F. Buddington as high—temperature replacements of skarn and microcline granite gneiss, A—14 are confined to a structural knot in granitic terrain near the border of the Adirondacks massif (Art. 35). Mag- netite in granite gneiss is locally accompanied by hypo- gene crystalline hematite and martite, and large deposits average about 25 percent recoverable iron. Geochemical studies in New Hampshire Chemical analyses of uranium and thorium in the Highlandcroft (Taconic), Oliverian (Acadian), and New Hampshire (Acadian) plutonic series of New Hampshire confirm that radioactivity is higher in the more felsic rocks of these series. In addition, accord— ing to J. B. Lyons (Art. 32), the much lower thor- ium-uranium ratios for pegmatites, contrasted with aplites, suggests that these coarse-grained rocks were formed by different processes of fractionation. Aquifers composed of glacial deposits During the course of recent studies in southeastern Massachusetts C. E. Shaw, Jr., and R. G. Petersen (1960) have concluded that the ground-water reservoir formed by stratified glacial drift along the Mattapoi- sett River is in hydraulic continuity with the stream and that the summer and autumn low flows of the Mattapoisett River are a measure of the minimum amount of water that can be developed on a sustained basis. In a study of pumping tests on wells in twelve ground-water reservoirs in glacial outwash in Rhode Island, S. M. Lang, W. H. Bierschenk, and W. B. Al— len (1960) found that coefficients of transmissibility ranged from 19,000 to 350,000 gpd (gallons per day) per foot, coefficients of permeability from 820 to 5,800 gpd per square foot, and coefficients of storage from 0.0008 to 0.20. Although outwash deposits are gen- erally productive, the wide range in permeability indi- cates a considerable variation in productivity from one reservoir to another and from place to place within any one reservoir. The wide range in coefficients of storage indicates a spread between water-table and substantially confined conditions. The average trans- missibility and permeability observed in the 12 reser- voirs studied are higher than for much of the outwash because many of the wells tested had been located and constructed after the sites had been explored by test drilling. Occurrence of water in bedrock Further insight into the occurrence and movement of ground water in consolidated rocks has been obtained by F. W. Trainer and R. C. Heath (Art. 315) from an area in the St. Lawrence River valley in northeastern New York. The most permeable zones in the Beek- mantown dolomite of this area are thin strata that contain moderately abundant cross fractures. These GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS thin strata are separated by thick beds in which cross fractures are widely spaced. One of these thin zones, lying nearly horizontal, apparently acts as a pipe that conducts water southward from Canada beneath the St. Lawrence River and Lake St. Lawrence to dis- charge areas along the Grass and Raquette Rivers in the United States. Chemical and physical quality of surface and ground water In a study of the quality of water in major drainage basins of Connecticut and extreme southeastern New York, F. H. Pauszek (1960) has observed that (a) dis- solved solids in surface water range from 26 to 216 ppm (parts per million), and the water is in general rela- tively soft, (b) water from streams in the Thames drainage basin is the softest—the observed range being only 10 to 33 ppm of hardness calculated as CaCOa, (c) in the upper Housatonic drainage basin, some streams that drain terrains underlain by limestone and dolomite are high in dissolved solids, and a preponder- ance of calcium and magnesium makes the water some- what harder, and (d) in all basins the water locally may be high in iron. The composition of the ground water in these basins is generally comparable to that of the streams, but has a greater range in amounts of dis- solved solids. Sediment discharge by Scantic Brook, a tributary of the Connecticut River, was less than 10 tons per day about 50 percent of the time. During the hurricane floods of 1955, however, 10,890 tons passed the Broad Brook station during the two days August 19 and 20. This was 70 percent of the total load for the year. Unusually high concentrations of chloride and sodi- um ions in water generally from deeper parts of the bedrock in the vicinity of Massena, N.Y., are attributed by R. C. Heath and E. H. Salvas (Art. 251) to sea wa- ter that entered the rocks from the Champlain Sea, which covered the area 4,500 to 7,000 years ago. The sea water has been diluted but is not yet completely flushed out. Flood magnitudes Mean annual floods are lower in streams flowing from the northerly slopes of the Adirondack Mountains than elsewhere in New York State. Snow constitutes nearly half the yearly precipitation, lasts from early fall to late spring, and releases moisture slowly. The ratios of the 10-, 25-, and 50-year floods to the mean annual floods are also the lowest in the State. In con— trast, streams in the southeastern part of New York, which also have small mean annual floods, have rela- tively high ratios for 25- and 50-year floods. These in- frequent large floods are caused by hurricanes and coastal storms. APPALACHIANS APPALACHIANS Geologic studies and mapping are in progress in many parts of the Appalachian region, and water re- sources investigations are in progress in cooperation with State agencies in every State in the region. In addition to the results reported below, information on mineral'deposits in the region is given on pages A—3 and A—4 to A—5; information on the IVatchung lava flows in New Jersey on page A—77; and information on the trace element content of soils and plants at Canandaigua, N.Y., and in Washington County, Md., on pages A—94 to A—95. Geologic mapping Detailed quadrangle mapping by Bruce Bryant and J. C. Reed, Jr., (1960) has definitely established that the fault on the southeast side of the Grandfather Mountain window, North Carolina, is continuous with the fault that bounds the window on the north and west. Reconnaissance by Bryant and Reed (Art. 316) has demonstrated that the quartzite of the Stokes County area, North Carolina, resembles that of the Chilhowee group in the Grandfather Mountain window, rather than quartzite of the Kings Mountain belt with which it had been tentatively correlated. Structural relations of the Stokes County area suggest that it also may be a window. Reconnaissance by J. C. Reed, J r., H. S. Johnson, J r., Bruce Bryant, Henry Bell III, and W. C. Overstreet in the Brevard schist belt of the Carolinas and northern Georgia has shown that the schist of this area is similar to the retrogressively metamorphosed rocks of the Table Rock quadrangle, previously mapped by Reed, and that the Brevard belt marks a major fault, as sug- gested earlier by Anna 1. Jonas. Overstreet and others (Art. 45) have recognized two major unconformities in the metasedimentary rocks of the South Carolina Piedmont. These unconformities can be correlated between the Kings Mountain belt and the Carolina slate belt. Lead-alpha age determina- tions on Zircon crystals from plutonic rocks that intrude the rocks above and below these unconformities fall in— to three groups, thereby establishing that the uncon- formities were formed between Cambrian and Ordovi- cian time and between Ordovician and Devonian time. An interesting byproduct of geologic mapping in the slate belt of North Carolina was the discovery by A. M. White and A. A. Stromquist (Art. 118) of an anomalous suite of heavy minerals in small tributary streams of the Yadkin River in the High Rock quad- rangle that probably were derived from remnant upland deposits laid down by the ancestral Yadkin River. Reconnaissance mapping by R. M. Hernon in north- western North Carolina has yielded good evidence, in- A—15 eluding relict amygdules, shape of the mass, and chemical composition, that the hornblende gneiss of that area was derived mainly from basalt flows. J. P. Minard (Art. 172) has mapped two belts of previously unrecognized end moraines that extend across Kittatinny Mountain, Sussex County, NJ The moraines and associated eskers form part of a discon- tinuous belt across the northern part of the State. They contain large amounts of sand and gravel suitable for use in construction, and locally are important ground—water reservoirs. Structural and tectonic studies P. B. King (Art. 41) has noted that mafic dikes of Triassic age trend northwestward in the segment of the Appalachians from Alabama to North Carolina, northward in the Virginia segment, and northeastward in the segment from Pennsylvania to New England. This pattern suggests the orientation of crustal stresses that existed in the Appalachian region during Triassic time. New insight into the structural history of the Mas— cot-Jefferson City zinc district, Tennessee, is provided by a structure contour map prepared by J. G. Bum— garner, P. K. Houston, J. E. Ricketts and Helmuth Wedow, Jr. The contours, drawn on the Rocky Valley thrust surface and on several stratigraphic horizons in the West New Market area, reveal that after the main thrusting, late deformation along fold axes affected both the stationary and thrust blocks as a unit and folded the thrust surface. L. D. Harris and Isidore Zietz have concluded from detailed mapping and aeromagnetic data that the struc- tural development of the Cumberland overthrust block began with major folding that involved the basement rocks. ‘ R. W. Johnson, J r., (1960b) has shown from inter- pretation of aeromagnetic and gravity data over a wide area in eastern Kentucky and Tennessee that structural trends in the basement are only locally coincident with those of Appalachian origin exposed at the present surface. The general lack of coincidence strongly suggests that the basement rocks beneath the Cumberland Plateau (and probably also those beneath the Ridge and Valley province) have their own struc- tural fabric of pre-Appalachian origin, a fabric that bears little if any direct relation to the overlying Appalachian structures. Aeromagnetic profiles in the vicinity of the Clark Hollow peridotite intrusion, Union County, Tenn., compared by R. W. Johnson, Jr., (1961) with com- puted anomalies for various selected models indicate that the intrusive body is a nearly vertical or north- west-dipping elliptical cylinder. Previously the body A—16 had been inferred from surface evidence to be a tabular or lens-shaped mass along the southeast-dipping Wal— len Valley fault. Structures within the plug suggest that it was emplaced before the period of thrusting and that its proximity to the Wallen Valley fault is coincidental. Geologic mapping and structural studies in the vi- cinity of the Southern and Western Middle anthracite coal fields by J. P. Trexler, G. H. Wood, J r., and H. H. Arndt (Art. 38), show that a previously unrecognized low- to high-angle unconformity separates rocks of the Catskill and Pocono formations in the western part of the Anthracite region. The rocks below the uncon- formity include the red-bed sequence at the top of the Catskill, the upper part of which contains a sparse flora of Early Mississippian age. These rocks were folded and partly truncated before the basal conglom- erate of the Pocono was deposited. The unconformity at the base of the Pocono formation provides the first structural evidence that the Acadian orogeny affected the rocks of the Ridge and Valley province in eastern Pennsylvania. T. A. Simpson (Art. 43) has observed that systems of open fractures associated with tight folds and major faults determine the direction of ground-water move— ment in the red-ore mines of the Birmingham district. The distinctive parallelism of the northeasterly-trend- ing folds and faults in the Birmingham district sug— gests that both resulted from pressure from the south- east. Studies of the joint systems and their relation to the folds and faults also revealed a second stress- field caused by north—south compression. Stratigraphic studies in the Ridge and Valley province The upper part of the Knox dolomite in Smyth County, Va., is closely similar to the upper part of the dolomite in the zinc district of eastern Tennessee, as shown by detailed studies by R. S. Young and Helmuth Wedow, Jr. Moreover, in both areas the zinc and barite deposits occur in the first major limestone unit below the unconformity at the top of the Knox. Geophysical study in the Maryland Piedmont In the Rockville quadrangle, Maryland, Andrew Griscom and D. L. Peterson (Art. 388) found that the shape, size, and trend of bodies of mafic rock beneath thick saprolite could be mapped by means of combined aeromagnetic, aeroradioactivity, and gravity data. Streamflow The marked influence of environmental factors on hydrology is illustrated by two recently completed studies in Tennessee. C. T. Jenkins (1960a) found that in Tennessee the mean annual flood is related to drainage area by the equation Q2.33=0A°~", in which GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Qua is by definition the mean annual flood having a 2.33-year recurrence interval, A is the drainage area, and 0 is a coefficient representing the influence of many physiographic, meteorologic, and other factors on the relation between area and the mean annual flood. Throughout the Blue Ridge and in the southeastern part of the Ridge and Valley province, 0 averaged 110. In the northern part of the Ridge and Valley province, it averaged 94. In spite of the greater precipitation along the mountain ridges and the precipitous terrain of the BlueRidge, these 0 values are significantly lower than the values of 145 and 170 reported for the Eastern Plateau region to the west. W. R. Eaton (1960) related annual 3-day minimum discharge to recurrence interval on a number of streams throughout Tennessee and found that streams have generally higher rates of base flow in the Applalachian region than elsewhere in Tennessee. The average low-flow yields of streams in the portion of the Appalachian region within North Carolina and southern Virginia were found by G. C. Goddard, J r., to be as much as eight times greater than in the eastern part of the Atlantic Coastal Plain. These results are based on the annual seven—day minium flow having an average recurrence interval of ten years. The average low-flow yields of several streams in southwestern North Carolina were 0.8 cubic feet per second per square mile, whereas the low—flow yields of many streams in the Atlantic Coastal Plain approached zero. Sediment yield Within the Appalachian region, J. W. Wark has found significant differences in computed annual sedi- ment yield between streams in the Ridge and Valley province and in the Piedmont Plateau. In the Ridge and Valley province, annual sediment yields are about 100 tons per square mile. In the Piedmont province the yields are 200 or more tons per square mile. In urban areas such as Washington, D.C., the yields are as high as 1,000 tons per square mile. ATLANTIC COASTAL PLAIN Recent work on the Atlantic Coastal Plain has in- cluded geochemical and petrographic investigations, geologic mapping, and hydrologic studies as summa- rized below. Information on phosphate and clay de— posits is given on page A—5, information on paleonto— logical work is given on pages A—59 to A—61, and infor- mation on the rate of erosion on Martha’s Vineyard on pages A—89 to A—90. Geochemical and petrographic investigation in Florida An earlier finding that extensive kaolinite deposits originate as a subaeria] weathering product of mont- morillonite in the Bone Valley formation of Florida ATLANTIC has been documented by Z. S. Altschuler by means of X-ray, chemical, and electron microscope studies. The alteration proceeds by acid leaching of Na, K, Ca, Si, and P from the montmorillonite and associated marine apatite, and the clay is transformed to kaolinite with- out going through an intermediate phase. The coex— tensive, very widespread Citronelle formation of peninsular Florida is also dominantly kaolinitic and markedly weathered. Because the Citronelle and the Bone Valley formations have many features in com— mon, it is likely that the kaolinite in the Citronelle is also of epigenetic origin. ‘ Geologic mapping Detailed field mapping in New Jersey has led J. P. Owens, J. P. Minard, and P. D. Blackmon (Art. 263) into studies of the clay-sized sediments in the coastal plain formations of New Jersey. The sediments con- tain various clays in combination with finely com- minuted minerals. The Hornerstown sand contains the distinctive glauconite clay; the Vincentown formation, calcite clay; the Kirkwood formation and Cohansey sand, quartz clay; and the Wenonah formation, chlo- rite clay. Montmorillonite is predominant in forma- tions younger than the Manasquan. The clay deposits indicate shallow marine to lagoonal and outer neritic depositional environments. Recent detailed field study and mapping of the Mount Laurel sand of New Jersey by Minard and Owens (Art. 173), supplemented by paleontologic studies by Ruth Todd, show that the Mount Laurel sand is a well- defined mappable unit throughout the State. A fauna from the basal part of the sand contains fossils of probable Navarro age. Fossils from the middle and upper parts of the formation are definitely of Navarro age, clearly indicating that the Mount Laurel belongs in the Monmouth group. Minard and Owens correlate the Kirkwood formation of Miocene age and Cohansey sand of Miocene( ?) age, with the Chesapeake group and with the basal part of the Brandywine formation in the Brandywine area of Maryland. The Kirkwood is markedly similar to the deeply eluviated upper part of the Chesapeake group. The Cohansey sand can be recognized in both Maryland and Virginia. Hydrologic studies As part of a study of the hydrology of the Coastal Plain of southeastern North Carolina, H. E. LeGrand (1960a) has described three major aquifers that occur in the thick sequence of Coastal Plain sediments. These are: (a) sandstone beds in formations of Cre— taceous age, which contain fresh artesian water in the west half of the area studied and salt water in the east half, (b) Tertiary limestone beds, which also contain . stone aquifers. COASTAL PLAIN A—17 artesian water, and (c) shallow surface sands, which contain water in reach of shallow drive-point wells. At least two of these aquifers are believed to be available in any part of the area. The fluctuations of sea water in estuaries along the North Carolina coast under varied conditions of tides, winds, and river discharge have been examined by T. H. Woodard and J. D. Thomas (1960). During October and November 1957, the beginning of the 1958 water year, salt water appeared at the following places: Chowan River near Edenhouse, Pasquotank River at Elizabeth City, Perquimans River at Hertford, and Albermarle Sound near Edenton. The Trent River near Rhems showed salt-water encroachment during October, November, August, and September. Salt water was present in the Neuse River at New Bern dur- ing all months except April and May. During periods of normal flow a salt-water body remains at New Bern until a high flow flushes out the salt water. The piezometric levels of the Cretaceous sand aquifer of the Savannah River basin indicate to G. E. Siple (1960a) that recharge to the aquifer occurs in the topographically high areas east of Aiken, S.C., and southwest of Augusta, Ga. A pronounced depression on the piezometric surface near the Savannah River downstream from Augusta indicates ground-water discharge extending from Augusta downstream to the vicinity of the Aiken-Barnwell County line. According to J. W. Stewart and M. G. Croft (1960), artesian pressures in the coastal counties of Georgia have declined about 10 to 90 feet since 1943, owing to increased use of ground water for industrial, municipal, and domestic supplies. In 1957 an estimated 279 mgd (million gallons per day) of ground water was dis- charged in the coastal counties; this amount is about twice that of 1943. The largest withdrawal of ground water was in the Brunswick area, where an estimated 90 mgd was discharged in 1957. Large and well- defined cones of depression occur in the piezometric surface in the Savannah, Brunswick, Jesup, and St. Marys—Fernandina areas. The largest and deepest cone is in the Savannah area, where the piezometric surface is as much as 120 feet below sea level. In the Brunswick area the piezometric surface outside the area of heaviest pumping, is 10 feet above sea level, but the deepest part of the cone probably is as much as 30 to 50 feet below sea level. In this area, the reduction of head by pumping has resulted in an encroachment of connate salt water from deeper lime- J. W. Stewart (1960) found that water from the deepest wells contains the largest amount of chloride, and that water from several shallow wells A—18 has shown a significant increase in chloride content in recent years. G. W. Leve (1961) has observed that the piezometric surface in the Fernandina area of northeastern Florida has declined 10 to 60 feet during the period 1880—1960. The ground-water pumpage in the area does not at present exceed the perennial yield of the aquifer, and only slight increases in the salt content of the water have been noted. In Volusia County most, if not all, of the fresh water in the Floridan aquifer is derived from rain falling in the recharge areas within the county, according to G. G. Wyrick (1960a). Strati- fication in the Floridan aquifer retards or prevents the upward movement of salt water. In contrast, in Martin County, W. F. Lichtler (1960) has found that there are zones of relatively fresh and salt water in the Floridan aquifer. Salt—water encroachment into the shallow nonartesian aquifer has not been extensive, but it is a threat in areas near bodies of salt water. Hydrologic studies near Fort Lauderdale, Fla., are summarized on page A—93. EASTERN PLATEAUS Recent geologic and hydrologic work of general inter- est in the Eastern Plateaus is described below. Much of this work is carried on in cooperation with State agencies. Work on clay in Kentucky is described on page A—5, and work in the Kentucky—Illinois mining district on page A—3. Geologic mapping in Kentucky In south—central Kentucky, R. E. Thaden and others (Art. 39) have delineated limestone reefs in the Fort Payne formation of Early Mississippian age. The reefs, which trend generally N. 65° to 80° W., range in size from small isloated lenses to thick bodies as much as a mile wide and 15 miles long. The reefs are of potential interest for petroleum as the Fort Payne has produced small amounts of oil and natural gas in some areas. During mapping and study of coal-bearing strata in the Kermit and Varney quadrangles, eastern Kentucky, J. W. Huddle and K. J. Englund have found that sand— stone members in the upper part of the Breathitt forma- tion of Early Pennsylvanian age are complex channel- in—channel deposits formed by meandering streams. As these streams shifted course across the coal-forming swamps they reworked previously deposited sand and plant debris. An understanding of the sedimentolog- ical history of these sandstones will aid in predicting the persistence and thickness of the underlying coal beds. Geologic mapping by K. J. Englund (Art. 177) in the southwestern part of the Cumberland overthrust block in the Middlesboro area of southeastern Ken— GEOLOGI-CAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS tucky, demonstrates that the Cumberland overthrust has been divided into subsidiary blocks by the Rocky Face fault and associated faults. Strike-slip move- ment along the Rocky Face fault is 1 to 2 miles. At its southeast end, the Rocky Face fault intersects a thrust fault with a similar amount of displacement toward the southeast. The rectangular subsidiary block delineated by this thrust fault on the southeast, the Pine Mountain thrust fault on the northwest, the Rocky Face strike-slip fault on the northeast, and the J acksboro strike-slip fault on the southwest has rotated relative to the remainder of the Cumberland overthrust block. Quaternary geology of the lower Ohio River Valley Continued studies by L. L. Ray indicate that ice sheets of two ages crossed the Ohio River Valley into Kentucky between Louisville and Mentor. The most widespread till, deposited during the first of these two glacial in- vasions of Kentucky, has been assigned to the Kansan stage primarily because of its deep alteration by weathering. The second ice sheet has been assigned to the Illinoian stage. Small patches of this younger till indicate that the ice crossed the Ohio Valley at several places and pushed small tongues into the lower parts of valleys tributary to the Ohio. Geologic history of Teays Valley, West Virginia E. C. Rhodehamel and C. W. Carlston have concluded that Teays Valley in West Virginia was probably aban- doned as a major stream channel in late Tertiary or early Pleistocene time, and then was subjected to pro- longed weathering. Owing to ponding, probably in Kansan time, laminated silty clay was deposited in the east—central part of the valley, and sand in the remain- der. These deposits are now deeply eroded. Probably during Illinoian time, ponding at a lower level resulted in deposition of silty clays in the western part of the valley. During a brief ponding in Wisconsin time, a veneer of ice—rafted pebbles was deposited. Paleontologic studies According to J. M. Schopf (Art. 95), coal balls found at three localities in eastern Kentucky are the oldest known in America and the first observed in the Appalachian coal fields. The coal balls occur in the marine Magoflin beds of Morse 5 of early Middle Penn- sylvanian (late Kanawha) age. They consist of lime- stone with more than 90 percent calcium carbonate and about 10 percent plant substance, including many new fossil plants. Coal balls supply important data on the mode of accumulation of coal, and on structure and history of ancient plants. 5 Morse, W. C., 1931, Pennsylvanian invertebrate fauna : Kentucky Geol. Survey. ser. 6, v. 36, p. 293—348. SHIELD AREA AND UPPER MISSISSIPI VALLEY Hydrologic studies in Kentucky A study of the geochemistry of natural waters of Kentucky, by G. E. Hendrickson and R. A. Krieger (1960), has revealed a recurring pattern in the rela- tion of chemical quality of water to stream discharge. Modifications in this pattern reflect differences in the hydrology and geochemistry of the basins. In a study of the occurrence of ground water in the Blue Grass region of Kentucky, W. N. Palmquist, J r., and F. R. Hall (1961), observed that only 6 percent of the domestic wells in valley bottoms were failures, whereas 35 percent of the hilltop wells failed to yield an adequate supply. In the Mammouth Cave area, Kentucky, G. E. Hendrickson (Art. 308) has found that under certain conditions about 60 percent of the water discharged at Echo River outlet is derived from local ground water and 40 percent from the Green River. The effects of oil field brines and acid mine waters on the composition of Kentucky streams is described on page A—76. Flood frequency areas in New York According to F. L. Robison, the Eastern Plateau region of New York can be divided into three flood- frequency areas. The ratios of 10, 25, and 50 year floods to the mean annual floods in the Tug Hill area east of Lake Ontario are very high, whereas the mean annual floods are near the median value for the State. In the Delaware River basin, both the ratios of the longer term floods and the mean annual floods are near the median values In the rest of the region the longer term ratios are small and the mean annual floods range from high values to some of the lowest. The results of other hydrologic investigations in the Eastern Plateaus region are given on pages A—92 and A—93. SHIELD AREA AND UPPER MSSISSIPPI VALLEY Results of recent geologic, geophysical, and hydro- logic studies in the Shield area and in the Upper Mississippi Valley are described in the following para- graphs. Much of this work is carried on in cooperation with State agencies. Additional information on lead- zinc deposits is given on page A—3. Geologic studies and mapping The ores in the Wisconsin zinc-lead district were deposited by concentrated brines rich in sodium, calcium, and chlorine, and lean in carbon dioxide, according to preliminary data by W. E. Hall, I. I. Friedman, A. V. Heyl, Jr., and M. R. Brock. Temper— ature of the solutions was about 100°C. (See p. A—96.) Minor elements and heavy mineral phenocrysts in volcanic ash of eastern Nebraska and western Iowa are A—19 reported by R. D. Miller, E. J. Young, and P. R. Barnett as supporting correlation of the deposits with ash of late Kansan-early Yarmouth age elsewhere in Nebraska and in Kansas. Lower and middle Precambrian rocks that underlie the Kelso Junction quadrangle, Iron County, Mich., have been found by K. L. Wier to differ from related rocks to the southeast in the following ways: (a) Meta- gabbro of the West Kiernan sill is more extensive, (b) the metavolcanic Hemlock formation is thicker and contains proportionally more pyroclastic material, and (c) the iron-bearing Amasa formation is practically nonmagnetic. Rocks in part of southern Florence County, Wis, are believed by C. E. Dutton to be a previously unrec- ognized upper part of the Michigamme slate of middle Precambrian age because of their apparent relation to rocks in Dickinson County, Mich. An assemblage of phyllite, chlorite and biotite schists, amphibolite, grun- eritic iron-formation, conglomeratic quartzite, quartz slate, and volcanic agglomerate is approximately 2,500 feet thick. Some lithologic units crop out along a strike length of almost 8 miles. In a study of the Marquette iron-bearing district, Michigan, J. E. Gair, R. E. Thaden, and B. J. Jones (Art. 178) have discovered that a synclinal fold at the east end of the district contains strata older than the ore-bearing Negaunee iron—formation. As the fold plunges eastward, the iron formation may exist beneath Lake Superior and the Paleozoic rocks of adjoining areas. I At the east end of the Marquette district the Kona dolomite of middle Precambrian age is silicified near some sedimentary and fault contacts in a way that suggests that silica was introduced laterally or upward, rather than downward from an erosional surface (Art. 179). Streams in sandstone differ from those of the same discharge in till by greater wavelength of meanders (more than 5: 1), Wider channels, steeper longitudinal profiles, lesser depths, and coarser bed material. These contrasts were recognized by J. T. Hack during a study near Ontonagon, Mich., Where stream valleys in some places have been cut through interbedded till and lake deposits into preglacial topographic highs composed of standstone of Keweenawan age. Geophysical surveys In parts of Ohio (Geauga, Wayne, Muskingum, Ross, and Montgomery Counties), where glacial till conceals the underlying bed rock, R. M. Hazlewood has deter— mined the depth to bed rock and the location of buried valleys quickly and easily by seismic refraction work. In one area the depth computed seismically was within 11/2 percent of that measured in a test drill hole. A—20 According to an interpretation of aeromagnetic data by J. W. Allingham and R. G. Bates (Art. 394), a syenite complex northwest of Wausau, Wis, is intruded by a circular plug that may be of alkalic composition. Spectrographic analyses have shown concentrations of niobium and rare earths in rocks of the syenite complex. In an area near Florence, Wis., C. E. Dutton and R. W. Johnson, Jr., have reconciled the results of aero- magnetic and geologic surveys. The study shows that anomalies with elongate contour patterns are mainly parallel to thin magnetite—bearing beds or lenses in metamorphosed sedimentary or volcanic rocks. Some anomalies of circular to elliptical pattern are related to concentrations of magnetite of undetermined origin in conglomerate, argillite, or thinly bedded phyllite; others are in localities where geologic data are un- available. Geophysical surveys in Minnesota are described on page A—68. Hydrologic studies W. D. Mitchell (Art. 6) has developed a method of calculating peak flows of streams affected by artificial storage and having only partial record stations. The method applies to sites where storage is proportional to the outflow discharge but possibly can be expanded to include sites where storage is not proportional. A method of estimating flood magnitudes and fre— quencies in Ohio, based on soil and topographic charac— teristics of drainage areas, has been devised by W. P. Cross and E. E. Webber. F. A. Watkins and J. S. Rosenshein (1960) have found that about 30,000 gallons of water per day moves under natural gradients through each mile-wide strip of the dolomitic limestone of Silurian age underlying the Bunker Hill Air Force Base near Peru, Ind. Recharge is through the overlying glacial drift. According to W. L. Steinhilber, O. J. Van Eck, and A. J. Feulner, the St. Peter sandstone in Clayton County, Iowa, is not recharged by the Mississippi River as was previously thought but, on the contrary, the sand- stone discharges water to the river. Recharge to the St. Peter is by percolation from the overlying Galena dolomite. Floods of May 1959, in the Au Gres and Rifle River basins, Michigan, according to L. E. Stoimenofl'. (1960) , resulted in the highest unit discharges for areas less than 15 square miles ever measured in the lower peninsula of Michigan. Robert Schneider and H. G. Rodis have found that the sand and gravel aquifers of Lyon County, Minn., are glacial outwash deposits that parallel the moraines but are thickened along southeast-trending channels. Some of the outwash was overridden by readvances of GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS the ice and where the drift is thick the aquifers may have no topographic expression. According to W. C. Walton and G. D. Scudder (1960) , pumpage of ground water in the Fairborn area of Green County, Ohio, can be increased from the present 6.5 million gallons a day to 50 million gallons a day without seriously affecting ground-water levels. Such an in- crease would induce infiltration of water into extensive outwash deposits along the Mad River. The river has a base flow of about 150 million gallons a day. Tracing of till sheets in northeastern Ohio by G. W. White (1960 and Art. 176), has led to the recognition by S. E. Norris and G. W. White (Art. 17) of many buried valleys. These valleys, cut into older glacial drift and filled with younger drift, have an important bearing on the occurrence of ground water. A map of the glacial deposits of'Ohio, recently completed by R. P. Gold- thwait and others, will greatly aid in the application of glacial geology to water resources investigations. Sediment yields during the floods of early 1959 in Ohio were low for the rate of streamflow because the ground was frozen and consequently was more resistant to erosion. R. J. Archer (1960) reported that in the floods of January 1959, sediment yields exceeded 200 tons per square mile in the Scioto River basin. In the floods of February 1959, the sediment yield in the Maumee River basin above Waterville was 121 tons per square mile. Studies of Paleozoic aquifers in Fond du Lac County, Wis., by T. G. Newport indicate that a decline of as much as 200 feet in water levels at Fond du Lac can be relieved by placing new wells to the northwest, toward the recharge area, and by utilizing water from the Niagara dolomite to the east. Other hydrologic studies in the region are reported on Pages A—92 and A—93. GULF COASTAL PLAIN AND MISSISSIPPI EMBAYMENT Geologic and hydrologic investigations in the Gulf Coastal Plain and Mississippi Embayment are both re— gional and local in scope. They have supplied data that have contributed much to economic development as well as to knowledge of the regional geology. Some of the more significant results of these studies are de— scribed below. The origin of uranium deposits in Karnes and adjoining counties, Texas, is discussed on page A—7. Correlation of the Carrizo sand in central Mississippi Embay- ment By the use of electrical logs, R. L. Hosman has traced the Carrizo sand, the basal unit of the Claiborne group in Arkansas, from Louisiana northward into Arkansas GULF COASTAL PLAIN AND MISSISSIPPI EMBAYMENT along the strike and thence eastward across the axis of the Mississippi structural trough into Mississippi. Pliocene(?) stratigraphy of the northern Mississippi Embay- ment During the course of geologic investigations in the southern part of the Jackson Purchase area of western Kentucky, being conducted in cooperation with the Kentucky Geological Survey, W. W. Olive, R. W. Davis, and T. W. Lambert have found that fluvial sedi- ments previously mapped as the Lafayette formation of Pliocene age and as sand and gravel of Pliocene and Pleistocene ages comprise a sequence consisting of a lower and an upper unit composed dominantly of gravel and sand, and a middle unit consisting mainly of clay beds. The maximum thickness of the sequence is about 80 feet. The lower and upper gravel units are as much as 40 and 20 feet thick, respectively, and the clay unit is from 5 to 40 feet thick. These deposits lie on an erosion surface of gentle to moderate relief cut in older Tertiary sediments. The basal unit thins, grades into sand, or is absent above the crests of buried hills. Effects of Pleistocene and Recent weathering of Tertiary sediments According to I. G. Sohn, S. M. Herrick, and T. W. Lambert (Art. 94) , calcareous foraminiferal shells from Paleocene strata. near Paducah, Ky., have been replaced by a zeolite and possibly barite. Microfaunas are rare in these rocks and this fact plus the fact that the CaCOa has been replaced by relatively insoluble minerals pro- vide indirect evidence to support a previous suggestion that prolonged leaching has removed calcareous material from Cretaceous and Tertiary rocks of the northern Mississippi Embayment. In the uranium—producing area of southeast Texas, A. D. Weeks has also observed that weathering of Ter- tiary sediments has resulted in the formation of zeolites. Other weathering effects in this area include the forma- tion of a caliche crust of calcium carbonate in the soil and the release of silica from tuffs. The released silica has cemented sands to form orthoquartzites. Ground-water storage In the San Antonio, Tex., area a long drought was broken by rains in 1957—58, and as a result the water levels in many parts of the aquifer in the Edwards limestone recovered from a record low in 1957 to a near record high in the spring of 1961. On the basis of this measured rise in water level, Sergio Garza estimates nearly 2 million acre-feet of water was added to storage in the ground-water reservoir between 1957 and 1961. A. H. Harder reports that 212 billion gallons of ground water was pumped for all purposes from the 608400 0—61r—3 A—21 main aquifer in the rice-farming area of southwestern Louisiana during 1959. In spite of this large annual withdrawal, the weighted-average water level computed fdr the entire area has not been lowered but has remained Virtually the same since 1955. New sources of ground water Separate investigations in northeastern Mississippi and west-central Alabama indicate that large ground- water supplies may be available from the Tuscaloosa group of Cretaceous age. A newly drilled well near Columbus, Miss, flowed 2,300 gpm from the aquifer of Cretaceous age. Electrical logs and water samples from oil-test wells show that fresh water occurs to a depth of about 2,000 feet in the Tuscaloosa group of west-central Alabama. As a result of the hydrologic studies made on behalf of the Atomic Energy Commission to improve tech- niques for detecting underground nuclear explosions, at least four fresh—water aquifers in Miocene and Oligo- cene strata have been discovered near the Bruinsburg and Tatum salt domes in Mississippi. Another aquifer contains salt water and may be used for brine disposal if mining in the salt domes by solution methods is undertaken. Roy Newcome, Jr. (1960), has shown by hydrologic tests that the alluvial aquifer along the Red River in Louisiana is capable of supplying much larger quantities of water than believed previously. G. T. Cardwell and J. R. Rollo (1960) report that the shallow-point bar deposits of Recent age along the Mississippi River south of Baton Rouge, La., are a potential source of fresh water but are virtually un- tapped. Although the deposits are fine grained they are in hydraulic connection with the river and would yield a dependable supply of water. Occurrence of salt water J. R. Rollo (1960) has used electrical logs and com- pletion data on oil and water wells to construct a fence diagram and a contour map showing the altitude of the base of fresh water and its relation to the subsurface geology in Louisiana. The contact between salt and fresh water reflects regional as well as many minor geo— logic structures. Although invasion of salt water was not extensive along the Gulf Coast during 1961, water from wells in the Houston and Galveston areas, Texas, showed slightly increased mineralization. G. T. Cardwell re- ported an increase in chloride content of water in a Pleistocene aquifer in Ascension Parish, La., caused by increased withdrawals. A—22 OZARK REGION AND EASTERN PLAINS Recent work in the Ozark Region and Eastern Plains, carried on in part in cooperation with State agencies, has yielded a considerable amount of geologic and hydrologic information of regional significance, which is summarized below. Additional information on evaporite deposits in New Mexico is given on pages A—6 and A—7, and information on coal in Arkansas is given on page A-8. Aeromagnetic studies in northeastern Arkansas and south- eastern Missouri Aeromagnetic data indicate that the crystalline base- ment is about 1 mile below the surface at the point where the White River crosses the Ozark escarpment near Newport, Ark. In Stoddard County, Mo., mag- netic data indicate that the basement is about 3,000 feet below the surface. Arkoma basin, Arkansas and Oklahoma Subsurface studies by E. E. Glick, B. R. Haley, E. A. Merewether, and S. E. Frezon indicate that within the Arkoma basin in Arkansas and Oklahoma the Atoka formation of Pennsylvanian age contains as many as 4 thin beds or zones of bentonite. The areal and strati- graphic distribution, and the mineralogy of these beds indicate that they will be useful in studies of the depo- sitional history of the Atoka formation and of the developmental history of the basin (Frezon and Schultz, Art. 181). Atoka formation in the Arkansas Valley, Arkansas The Atoka formation of Pennsylvanian age in the central part of the Arkansas Valley, Ark., increases in thickness from about 3,050 feet in northern Johnson County to about 10,750 feet in northern Yell County, a distance of 28 miles. E. A. Merewether (Art. 182) has reported that the southward thickening results largely from an increase in the shale units in the formation. Development of the Fredonia anticline in Wilson County, Kansas Analysis of measured sections and well records in Wilson County, Kans., by H. C. Wagner has shown that uplift on the Fredonia anticline began in Missis- sippian time and continued intermittently through Pennsylvanian time. The uplift controlled, to some degree, places of accumulation of sand and limestone debris, which later served as petroleum reservoirs. Movement on the Fredonia anticline during Late Pennsylvanian time is well documented in measured surface sections. _ GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Austin chalk, Val Verde and Terrell Counties, Texas The concept of a widespread hiatus at the base of the Austin chalk is not supported by findings of V. L. Free— man (1961), who reports that neither a depositional or erosional break nor a faunal gap is present at the base of the unit in Val Verde and Terrell Counties, Tex. In addition, the lowest beds assigned to the Austin chalk, previously considered to be of Coniacian age, are now considered by Freeman to be of Turonian age. Movement underground of artificially-induced brine As part of a study of the geology and water resources of Cowley County, Kans., C. K. Bayne has obtained data on the movement of underground water. More than 30 years ago a moderate amount of highly mineral— ized oil field brine was discharged by means of a well into an aquifer in terrace deposits in the Arkansas River valley near Winfield. This brine is now moving down the valley as a discrete body at a rate of about a quarter of a mile per year. Buried valley near Manhattan, Kansas According to H. V. Beck (Art. 351) a buried valley northwest of Manhattan, Kans., was occupied by the Kansas River in pre-Kansan time and possibly as late as Illinoian time. Later, the Kansas River changed its course when a meander cut through the area between Bluemont Hill and K Hill. The gravel in the buried valley is an important source of ground water. Depressions on the High Plains As part of a study of artificial recharge, test holes were drilled across closed depressions on the High Plains. They show that the caliche caprock generally present beneath the surface of the plain dips toward the centers of the depressions, thins from the outer margins toward the centers, and is absent at the cen- ters. J. S. Havens (Art. 52) has therefore concluded that the depressions have been caused by solution of the caliche caprock and have been further deepened by removal of sand by deflation. Salt water and halite at shallow depths in Oklahoma Recent work by P. E. Ward and A. R. Leonard (Art. 341) has shown that salt and salt water underlie large areas in western Oklahoma at shallow depths. The salt, which occurs as beds, lenses, and stringers of halite interbedded with Permian shale, siltstone, dolomite, and gypsum, is within 200 feet of the land surface in a few places in northwestern and southwestern Okla- homa, and at one place in Woods County it was found at a depth of 70 feet in a core hole. Although shallow mineralized salt water is associ— ated with halite in many places, it occurs in the absence NORTHERN ROCKIES AND PLAINS of halite in many others. Around some geologic struc- tures, the depth to salt water changes markedly within short distances. Maps being compiled by D. L. Hart, J r., show that the depth to salt water in one place in south-central Oklahoma increases from 400 feet to 1,100 feet in a distance of 4 miles. In many places, salty water is within 200 feet of the land surface, par- ticularly in western Oklahoma. In contrast to the shallow salt water, potable ground water extends to depths of a few hundred feet in several of the red-bed sandstones of Pennsylvanian and Per- mian age. In the Arbuckle limestone in south-central Oklahoma, fresh ground water extends to depths of more than 2,500 feet. Water withdrawal in Reeves County, Texas According to William Ogilbee and J. F. Wesselman, water for irrigation in Reeves County, Tex., is being withdrawn from the aquifer at a much greater rate than the rate of recharge. The number of irrigation wells in the county has increased from 60 in 1946 to more than 900 in 1959. The water levels in the heavily pumped area have declined persistently since 1946, the maximum decline being about 200 feet. In 1958, about 40 million acre-feet of water remained in storage, but only a part of this water is available to wells. Aquifer filled in Haskel and Knox Counties, Texas William Ogilbee and F. L. Osborne, Jr., have re- ported that the Seymore formation in Haskel and Knox Counties, which 60 years ago contained only small quantities of saline water near the base, is now completely filled. The Seymore formation is a thin alluvial deposit overlying red beds of Permian age. The rise in the water level is attributed to the beginning of cultivation and the consequent removal of the large growth of mesquite and other phreatophytic vegetation. Reservoir evaporation As part of a study of evaporation and seepage losses from reservoirs in the Honey Creek basin, 35 miles north of Dallas, Tex., F. W. Kennon (Art. 50) has con- cluded that the average annual evaporation for a typical small reservoir is 5.1 feet. The average annual precipitation for the period 1953—59 was 2.9 feet. Hence, the net annual evaporation loss was 2.2 feet. NORTHERN ROCKIES AND PLAINS Geologic, geophysical, and ground-water studies are being carried on in the Northern Rocky Mountains and Plains in many areas of widely different characteristics. Some of the recent findings resulting from these studies are summarized below. Additional information on mineral deposits is given on pages A—l to A—8. The A—23 origin of carbonatites in the Bearpaw Mountains, Mont, is discussed on page A—7 7 , and the isotopic com- position of lead in major ore deposits in the region is discussed on page A—96. Geologic studies in northeastern Washington and northern Idaho According to R. G. Yates the lead-zinc deposits in the N orthp‘ort mining district, northern Stevens County, Wash., are thermally related to, but not necessarily derived from, the Spirit pluton, a granodiorite mass of probable Cretaceous age. In the Hunters quadrangle, mapping by A. B. Camp- bell indicates that the Old Dominion limestone of Weaver 6, equivalent at least in part to the Cambrian Metaline limestone, overlaps the Maitlen phyllite from north to south. New paleontologic evidence suggests that the Old Dominion is younger in the vicinity of Hunters, Wash., than rocks of the same lithologic facies farther north. In the Mount Spokane and Greenacres quadrangles and in adjacent areas, A. E. Weissenborn, P. L. Weis, and V. C. Fryklund have recognized Belt rocks of Precambrian age. This occurrence is farther west than any recognized previously. In the Mount Spokane quadrangle, Weissenborn has shown that meta-autunite is restricted to a muscovite-quartz monzonite in which mafic minerals are sparse or absent. In the Clark Fork area of Odaho, J. E. Harrison and others (Art. 67) attribute mosaic block faulting in Belt rocks to vertical adjustment of the crustal rocks during emplacement of a granodiorite batholith in Cretaceous time. The existence of the still-buried batholith is indicated by positive magnetic anomalies, by scattered outcrops of small stocks, and by small areas of higher grade metamorphism in the Belt rocks. Geologic studies in central Idaho In the Vicinity of the northwest margin of the Idaho batholith, Anna Hietanen (Art. 345) has found that the grade of metamorphism in the country rocks in- creases progressivly towards the batholith from the greenschist facies to the amphibolite facies. In general, the type of folding also changes with increasing metamorphic grade—open folds are typical of the greenschist facies, and isoclinal flow folds are typical of the amphibolite facies near the batholith. In a study of the Idaho batholith in the Yellow Pine quadrangle, B. F. Leonard has recognized a small out- lier of Challis volcanics of Tertiary age near Riordan Lake, about 10 miles farther southwest than this unit of flow and pyroclastic rocks had been traced previ- ously. Heat and solution from the volcanic mass have ”Weaver. 0. E., 1920, The mineral resources of Stevens County: Washington Geol. Survey Bull. no. 20. A—24 caused mild argillization of the underlying granodiorite of the Idaho batholith, and have induced retrograde metamorphism in sillimanite-biotite schist and marble inclusions in the granodiorite. Four glacial stages, one probably of early Pleistocene age, have been recognized by E. T. Ruppel and M. H. Hait, Jr., (Art. 68), in the central part of the Lemhi Range, and the relation of deposits laid down during these stages to landforms suggests the presence of remnants of a preglacial pedimentlike surface. The central part of the Lemhi Range is underlain mainly by Precambrian and early Paleozoic rocks that are folded into a large overturned anticline and broken by a number of west-dipping overthrust faults. Geologic and geophysical studies in western Montana In the western part of the Sun River Canyon area, M. R. Mudge reports the presence of a western'facies of the Ferdig shale member of the Upper Cretaceous Marias River shale. The western facies is dominantly fine— to medium-grained sandstone with minor amounts of interbedded mudstone, whereas the eastern facies is mainly silty mudstone with minor amounts of inter- bedded ‘fine-grained sandstone. A slightly different fauna occurs in each facies. The western facies is simi- lar in lithology and fauna to the Cardium standstone of Alberta. In the Wolf Creek area, R. G. Schmidt (Art. 211) has recognized a low-angle fault called the Cobern Mountain overthrust. Along this fault, rocks of the Two Medicine formation of Late Cretaceous age and overlying rocks of the Adel Mountain volcanics of Lyons 7 have been thrust northeastward upon younger rocks of the Adel Mountain volcanics. In the vicinity of Cobern Mountain the net slip along this fault is more than 2 miles and the fault plane is folded. The struc- tural relations along the Cobern Mountain overthrust, together with the occurrence of fossils of supposed Horsethief age beneath rocks of the Adel Mountain volcanics (notably at Cobern Mountain), indicate that the Adel Mountain volcanics are probably equivalent to part of the Saint Mary River formation of Late Cre— taceous age and are thus considerably younger than the volcanic rocks of the Two Medicine formation. Geophysical studies by W. T. Kinoshita and W. E. Davis in the Townsend Valley and Three Forks basin indicate that most of the major structural features known from surface mapping are outlined by magnetic anomalies associated with igneous and metamorphic rocks. A strong anomaly in the eastern part of the Townsend Valley shows that the Lombard overthrust extends northward beneath the Cenozoic fill in the valley “Lyons, J. B., 19441 Igneous rocks of the Northern Big Belt range, Montana: Geol. Soc. America Bull., v. 55, no. 4, p. 449, 452. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS to join with thrust faults along the west flank of the Big Belt Mountains southeast of Canyon Ferry. An— other anomaly in the western part of the Three Forks basin indicates that the Jefferson Canyon thrust fault swings northeastward to join a thrust zone a few miles southwest of Three Forks junction. The magnetic anomalies also indicate that the anticlines exposed in the Limestone Hills and the Hossfeldt Hills are parts of a continuous structure, the southern part of which has been ofl’set eastward about 2 miles, probably along a series of northwest-trending faults. Near Livingston, the Madison group has been shown by A. E. Roberts (Art. 126) to be a carbonate sequence of many marine cycles alternating between calcium and magnesium deposition during Kinderhook, Osage, and Meramec time. Insoluble residue samples from the upper member of the group contain a phosphate-sul— phate mineral suggesting a lithofacies relation with evaporite-dolomite rocks of the Charles formation farther northeast. In the Greenhorn and Gravelly Ranges, west of the Madison River, the Precambrian and Paleozoic rocks have been displaced several miles, according to J. B. Hadley. In the northern part of the Gravelly Range, Hadley has found remnants of thin rhyolite ash flows, in part welded, that may be marginal deposits of the Tertiary Yellowstone volcanic province. In the Highland Mountains south of Butte, M. R. Klepper and H. W. Smedes have mapped three well- defined east-trending plutons in the southern part of the Boulder batholith. The batholith margin in this area apparently was controlled in large part by an east- trending prebatholith fault zone, along which the plutons were emplaced. At the eastern border of the Idaho batholith, in the headwaters of the West Fork of the Bitterroot River, geologic mapping by R. L. Parker has shown that phyllite, quartzite, and schist (believed to be part of the Precambrian Belt series) grade into gneiss along a contact that parallels the schistosity in both the gneiss and the schist. Apparently both the gneiss and the schist were formed from Belt rocks by metamorphism that accompanied emplacement of the Idaho batholith, and the gneissic rocks, therefore, are not pre—Belt metamorphic rocks as had been supposed previously. Alternative hypotheses on deformation accompanying the Hebgen Lake earthquake, Montana Studies in the vicinity of Hebgen Lake since the dis- astrous earthquake of August 17, 1959, have led to two somewhat different hypotheses to account for the ob- served deformation. The dual-basin hypothesis, set forth by I. J. Witkind (Art. 346), suggests that two separate basins were simultaneously deformed by re— ' NORTHERN ROCKIES AND PLAINS newed movement along existing range front faults bordering northwest-trending tilted fault blocks. The single-basin hypothesis, proposed by W. B. Myers and Warren Hamilton (Art. 347), sugests that the struc- tures of the east-trending Centennial Range and Valley are being extended across the north- and northwest— trending structures of the Madison Range and flanking valleys, to define a new structural basin that ends ob- liquely and abruptly against reactivated northwest- trending faults northeast of Hebgen Lake. Geologic and geophysical studies in the Bearpaw Mountains, Montana Geologic mapping by B. C. Hearn, Jr., and W. C. Swadley in the southeastern part of the Bearpaw Moun- tains has disclosed a ringlike belt of intrusive igneous rocks and severely deformed volcanic and sedimentary rocks 3 to 5 miles Wide surrounding a central area of about 15 square miles that is less deformed and is almost devoid of igneous rocks. In the ringlike belt, collapse faults are common. The aggregate stratigraphic dis- placement on some of the faults is as much as 9,000 feet. In the western Bearpaw Mountains, K. G. Books has found a close association between magnetic anomalies and topographic highs, which he believes indicates a relatively thin cover of volcanic rocks. This conclusion is supported by rock thicknesses calculated from rem- anent magnetic data. Geologic and geophysical studies in parts of Wyoming, south- eastern Idaho, and northeastern Utah In the northwestern part of Park County, Wyo., W. G. Pierce has mapped a decollement type of fault, the Reef Creek detachment fault. The fault is slightly older than the Heart Mountain detachment fault, and the rocks moved on the Reef Creek fault have been scattered still farther by transportation atop masses moved by the Heart Mountain fault. Gravity measurements by L. C. Pakiser and H. L. Baldwin, J r., (Art. 104) at 890 stations in Yellowstone National Park and adjoining parts of Idaho, Montana, and Wyoming reveal a strong gravity low in the vicinity of the Yellowstone Plateau, and a narrow gravity low along the Madison Valley, Mont. (See p. A—70.) In the Afton area, western Wyoming, J. D. Love (Art. 250) reports large reserves of vanadium in phos- phate rock of the Phosphoria formation. (See p. A—4.) In the Fossil Basin, north and west of Kemmerer, Wyo., W. W. Rubey, S. S. Oriel, and J. I. Tracey (Art. 64) have studied the Upper Cretaceous and Lower Ter— tiary rocks in detail. They conclude, on the basis of fossil vertebrates, mollusks, leaves, and pollen, that the Evanston formation is of latest Cretaceous to early late A—25 Paleocene age. They also recognize a peripheral diamictite facies (Art. 62) in the Wasatch formation in the Fossil Basin, and suggest its accumulation through mudflow and solifluction. Northwest of Nounan, Idaho, mapping by F. C. Arm- strong shows that what has been thought to be part of a thrust plate of Ordovician quartzite resting on Triassic limestone is actually a landslide mass of Cambrian quartzite. In the upper Green River Valley, Utah, W. R. Hansen finds that the Uinta anticline is a large composite fold having two main closures alined on a single east—trend- ing axis. One closure is centered near Gilbert Peak, and the other near Browns Park. Hansen’s work has also shown that large scale normal faulting began in the northeastern Uinta Mountains in early Tertiary time, possibly in the Oligocene, before the cutting of the Gilbert Peak erosion surface. The cutting of the ero- sion surface later was terminated by renewed faulting and warping. Studies by W. H. Bradley of the paleohydrology and paleoclimatology of the Eocene Green River forma— tion of Wyoming have revealed that in a period of about 1 million years during the middle Eocene, the climate of Wyoming changed from moist to arid (as arid as the Great Salt Lake area today) and then be- came moist again. (See p. A—7 8.) Stratigraphic studies in parts of eastern Montana and Wyoming Studies of the Pierre shale by J. R. Gill (Art. 352) show that the formation comprises a series of trans- gressive deposits that wedge out eastward. The Sharon Springs member of the Pierre consists of widespread persistent beds of bentonite and organic-rich shale which provide an easily identifiable marker for subsur- face and surface investigations. Paleontologic studies by W. A. Cobban have shown that this unit contains a distinctive ammonite fauna, indicating that it is an excellent time marker as well as a distinctive lithologic marker. (See also p. A—79.) Geologic and geophysical studies in the Black Hills, South Dakota and Wyoming Study of about 110 samples of rocks of the Inyan Kara group by L. G. Schultz and W. J. Mapel (Art. 210) shows that the Lakota and overlying Fall River formations contain the same clay minerals but in difl’er— ent proportions. A zone of kaolinite and ferruginous spherules at the top of the Lakota formation indicates a weathered zone at the Lakota—Fall River contact. The relations are similar to those described at the same horizon along the Colorado Front Range, suggesting A—26 that the period of weathering may have been of re— gional extent. The kaolinite zone may aid in corre- lating Lower Cretaceous rocks in the Western Interior. In the southern Black Hills, recent work by G. B. Gott, E. V. Post, and D. E. Wolcott on rocks of the Inyan Kara group has shown that all the major con- glomeratic sandstones are in the Fuson member of the Lakota formation, and that the Fuson member consti- tutes nearly all the Lakota formation in the northwest- ern Black Hills. The Chilson member of the Lakota formation as defined by E. V. Post and Henry Bell III (Art. 349) is largely restricted to the southern Black Hills. Preliminary interpretation by R. M. Hazlewood of data from a gravity survey of the Black Hills shows that there is a steep gravity gradient along the west flank of the northern Black Hills, and that there is excellent correlation between gravity data and known geology. The east flank of the Black Hills is character- ized by a series of gravity highs and lows that trend parallel to the uplift. In the central part of the Black Hills most of the small anomalies are associated with amphibolite bodies. Possible Early Devonian seaway An Early Devonian seaway, which may have occu- pied a geosynclinal trough west of the present Rocky Mountains, has been inferred by C. A. Sandberg (1961b) as an outgrowth of his study of Devonian stratigraphy in the Williston basin. The Beartooth Butte formation and equivalent strata in the northern Rocky Mountain region were deposited along the east— ern margin of the sea. Discontinuous sparsely fossil- iferous shallow-water deposits of similar lithology and stratigraphic position are reported from the Northwest Territories in Canada to east-central and southern Arizona. The distribution of these rocks suggests that the Early Devonian seaway may have extended from the Arctic Ocean as far south as the Mexican border. Biostratigraphic studies of upper Paleozoic rocks Analysis by W. J. Sando and J. T. Dutro, Jr., of brachiopod and coral faunas in the Madison group and equivalent rocks in the northern Rocky Mountains suggests correlations with the Mississippian of the Mis- sissippi Valley type region. The lower half of the Lodgepole limestone is approximately correlative with the upper part of the Kinderhook (Chouteau equiva- lents). The upper part of the Lodgepole and lower part of the Mission Canyon (including the related Brazer dolomite) are of Osage age, whereas the up- permost Mission Canyon is considered to be of Mera— mec age. Fasciculate lithostrotionoid corals, together with certain spiriferoid brachiopods, lend credence to GEOLOGICAL SURVEY RESEARCH 196l—SYNOPSIS OF RESULTS the Meramec correlation. Kinderhook-Osage and Osage—Meramec boundaries are difficult to determine in Madison rocks because of apparent overlapping of ranges of fossils characteristic of the series in the type region. Endothyrid Foraminifera in Carboniferous rocks of the Mackay quadrangle, Idaho, have been shown by Betty A. L. Skipp (Art. 236) to range in age from Early Mississippian to Pennsylvanian, and to be useful for interpretation of stratigraphic relations in the thick sequence of miogeosynclinal rocks of that area. Recent collections of Permian corals from the Phos- phoria, Park City, and Shedhorn formations have been studied by Helen Duncan (Art. 99), and have added data on the geographic distribution of a coral zone that is fairly widely developed in the Lower Permian rocks of Idaho, Wyoming, and Montana. The presence of corals in these rocks had not been recognized earlier. Ground-water investigations in Idaho Many of the larger consumers of water in the Mos- cow Basin, Latah County, Idaho, depend on artesian aquifers in the Latah formation (Stevens, 1960). Large withdrawals from this formation for more than 60 years have caused a continuing decline in artesian pressure, which has been accelerated during the last few years. Use of surface water is suggested both as a supplemental source and for artificial recharge of the aquifers. Ground-water investigations in Montana The northern part of the Deer Lodge Valley con- tains a thick section of Eocene, Miocene, Pliocene, and Quaternary deposits laid down in a structural valley formed in Late Cretaceous or Paleocene time (Koni— zeski, McMurtrey, and Brietkrietz, 1961). Moderately large supplies of water are obtained from both the Tertiary and the Quaternary deposits. In northeastern Blaine County, the Flaxville forma- tion, which underlies a plateau known as the Big Flat, contains an estimated 300,000 acre—feet of water in storage, and receives about 5,000 acre-feet per year of recharge (Zimmerman, 1960). Wells in the Flaxville yield large supplies of water of good quality, whereas only small supplies of generally poor quality water are obtainable from the underlying Upper Cretaceous formations. Ground-water investigations in Wyoming An investigation in the vicinity of Osage, Weston County, by H. A. Whitcomb has revealed that the flow of artesian wells tapping the Lakota formation has declined considerably in the last 20 to 30 years, and that some of the wells no longer flow. The declines SOUTHERN ROCKIES AND PLAINS in flow are attributed mainly to increased withdrawal, but in part to decreased recharge and to possible de- terioration of well casings or incrustation of perfora- tions in casings. In northern and western Crook County, Whitcomb has found that moderate to large supplies of water are obtainable from deep artesian wells tapping the Min— nelusa formation and underlying Pahasapa limestone. The Fall River and Lakota formations are the most widely developed aquifers in the area, but generally yield only small supplies of water. Whitcomb has also found that the Arikaree forma- tion is a moderately good aquifer in the southern part of Niobrara County Where well yields range from 150 to 750 gpm (gallons per minute) and average 500 gpm. Wells near the Hartville Hills generally have the higher yields owing to fracturing of the Arikaree by post— Miocene uplift. An estimated 5 to 8 million gallons per day moves eastward through the Arikaree into Nebraska. Ground-water investigations in North Dakota Studies in Burleigh, Kidder, and Stutsman Counties, N. Dak., reveal that the larger yields of ground water are obtained from outwash plains, valley outwash, and buried preglacial or interglacial channels that contain stratified sand and gravel, but some water is obtained from lenses of stratified material within till. Near Alexander, McKenzie County, small supplies of water of relatively poor quality are obtained from beds of sand and lignite in the Tongue River member of the Fort Union formation, and from alluvium and colluvium. Ground-water investigations in South Dakota A statewide study of artesian wells in South Dakota, by R. W. Davis and others (1961), has revealed that 16 million gallons of water per day is being discharged by 44 uncontrolled flowing artesian wells in the Mis- souri River Valley. Most of these wells tap the Dakota sandstone. Near the Black Hills, flowing wells yield large quantities of water from the Minnelusa sandstone and Pahasapa limestone. At least nine other artesian aquifers are tapped by wells in western South Dakota. The piezometric surface for wells tapping the Fall River formation has declined about 10 feet since 1956 near Edgemont, in the southern Black Hills, but has not declined since 1959 in eastern Custer County. SOUTHERN ROCKIES AND PLAINS Geologic and hydrologic investigations in the South- ern Rockies and Plains during the fiscal year 1961 have yielded results of regional or broad local significance A—27 , in the many fields summarized below. Other results are presented in other sections of this report as follows: mineral deposits, pages A—l to A—8; geophysical studies, page A—70; engineering studies, page A—88; and geochemical prospecting, page A—95. Geology of volcanic terrains in Colorado and New Mexico In the San Juan Mountains, Colo., geologic mapping by R. G. Luedke in the area north of and between the Silverton and Lake City calderas of late Tertiary age has confirmed the suspected occurrence of an older and larger caldera or volcano-tectonic depression upon which were superposed the two younger calderas. Fol— lowing a catastrophic eruption of welded ash-flow tuifs (Eureka rhyolite of the Miocene Silverton volcanic series), there was cauldron subsidence followed by dom- ing and establishment of a northeast-trending central graben. Continued mapping around the Creede caldera by T. A. Steven and J. C. Ratté disclosed a major graben extending southeast from the caldera in the vicinity of the Rio Grande. The Wagon Wheel Gap fluorspar mine is along one of these graben faults, but no other mineral deposits have yet been discovered. In the Powderhorn district, Colorado, on the north margin of the San Juan volcanic field, J. C. Olson and D. C. Hedlund have found that the volcanic rocks of Tertiary age include a distinctive sequence of four principal welded—tufi' units. Each unit commonly com- prises several mappable lithologic varieties, including vitric and devitrified welded tufl’ and unconsolidated tufl’. The similar lithologic succession in different areas indicates the wide lateral extent of each welded-tufl' unit. Mapping of the volcanic rocks of the J emez Moun- tains, N. Mex., by R. L. Smith, R. A. Bailey, and C. S. Ross (Art. 340) shows that the Valles caldera contains a complexly faulted central structural dome encircled by a peripheral ring of volcanic domes that are analogous at depth to a central stock and ring dike. Time and spatial relations of doming and vulcanism indicate that some ring dikes were intruded during postsubsidence doming of the caldera floor rather than during cauldron subsidence as suggested by Clough, Maufe, and Bailey 3 in their classic study of the Glen Coe cauldron of Scotland. Geology of Precambrian rocks Continued studies in the east—central part of the Front Range, Colo., by J. D. Wells, D. M. Sheridan, and A. L. Albee (Art. 196) indicate that the biotite gneisses of the Idaho Springs formation and the quartz- ‘Clough, C. T., Maufe, H. B., and Bailey, E. B., 1909, The cauldron- subsidence of Glen Coe, and the associated igneous phenomena: Geol. Soc. London Quart. Jour., v. 65, p. 669. A—28 ite along Coal Creek were deformed twice by plastic deformation and once by cataclastic deformation dur— ing Precambrian time. The cataclastic deformation is confined to the recently named Idaho Springs- Ralston shear zone and aside from faulting is the youngest episode of Precambrian tectonism recognized in this part of the Front Range. Geological mapping of the Precambrian rocks in the drainage of the Gunnison River, in southwestern Colo- rado, is delineating the lithologic succession and meta- morphic and intrusive history of this previously little known complex. In the Powderhorn district, J. C. Olson and D. C. Hedlund have distinguished three principal groups of layered metamorphic rocks: (a) hornblende schist or greenstone, consisting dominantly of metamorphosed basaltic to andesitic volcanic rocks, (b) felsitic volcanic rocks, and (c) quartz-biotite schist, consisting principally of metasedimentary rocks. Some of the metasedimentary layers associated with the fel- sitic volcanic rocks contain staurolite and kyanite. Nearby, in the Black Canyon of the Gunnison, mapping by W. R. Hansen has disclosed that the dominant Pre— cambrian schist is intruded, from oldest to youngest, by (a) pegmatites, (b) lamprophyric dikes (in upper canyon), (d) quartz monzonite plutons, (d) Curecanti granite (in upper canyon) and Vernal Mesa granite (in lower canyon), (e) pegmatite and aplite, and (f) diaba'se. Geology of major sedimentary basins In the southwestern part of North Park, Colo., mapping by W. J. Hail, J r., shows that the lower (Pale- ocene) part of the Coalmont formation overlaps the entire sedimentary sequence of pre-Tertiary rocks and, to the west in the Park Range, lies directly on Pre- cambrian crystalline rocks. On the western margin of the Denver basin, oil- producing anticlines at Berthoud, Colo., and at Hay- stack Mountain north of Boulder, Colo., have been delineated in detail by W. A. Cobban and G. R. Scott by means of mapping of ammonite zones in the Pierre shale. To the north, in southeastern Wyoming, L. W. McGrew has recognized the following previously unknown Cenozoic rock units: (a) Early Eocene(?) conglomerate that lies with angular discordance on Per- mian red beds and is overlain with angular discordance by the White River formation, (b) fluvial and laws- trine deposits of middle to late Miocene age, (0) fluvial deposits of Pliocene( 2) age in fault contact with the Arikaree formation (Miocene), and (d) middle to late Pleistocene fluvial and lacustrine deposits that lie 800 feet and 300 feet respectively above the present level of the North Platte River. GEOLOGICAL SURVEY RESEARCH “Nil—SYNOPSIS OF RESULTS According to D. L. Gaskill (Art. 96) the Ohio Creek conglomerate of the Anthracite basin area, about 20 miles north-northwest of Gunnison, Colo., now has been dated as Paleocene on the basis of plant fossils. The conglomerate unconformably overlies strata assigned to the Mesaverde formation over a wide ‘area in the eastern part of the Uinta Basin; it is overlain by the Tertiary Wasatch formation. Rocks of Mississippian and probable Devonian age in the Sangre de Cristo Mountains On the basis of stratigraphic studies in the Sangre de Cristo Mountains of northern New Mexico, E. H. Baltz and C. B. Read (1960) report two new formations. The Espiritu Santo formation of Devonian( ?) age consists of sandstone, sandy dolomitic limestone, and crystalline and elastic limestone. The Tererro forma— tion, separated from the Espiritu Santo formation by an erosional unconformity, contains three recognizable members—the Macho, Manuelitas, and Cowles. The formation consists of limestone breccia and conglom- erate, crystalline limestone, and calcarenite. A sparse faunule in the Manuelitas member indicates an Early Mississippiaii age for that part of the formation. Geology of parts of Nebraska .. Studies in the southern part of Nebraska by R. D. Miller, Richard Van Horn, Ernest Dobrovolny, and the late L. P. Buck indicate that volcanic ash exposed along the Republican River correlates with the Pearl- ette ash member of Kansas. The ash is included within the Sappa formation of late Kansan age and provides a widespread, reliable, and easily recognizable stratigraphic (marker. Alluvial terrace deposits along North Loup River in central Nebraska were formed about 10,850 years ago, according to carbon—14 determinations of shell material by Meyer Rubin. Previously, the lower part of the terrace had been dated from mollusks as late Kan- san to Illinoian. The material giving the 10,850 year date underlies what R. D. Miller believes to be the Brady soil of Schultz and Stout.9 According to Miller and G. R. Scott, the newly determined date supports placing the Brady soil development in post—Two Creeks time. Ground-water recharge In the Frenchman Creek basin above Palisade, Nebr., W. D. E. Cardwell and E. D. Jenkins have determined that the rate of annual recharge t0 the ground-water reservoir (principally the Ogallala formation) is 0.9 inch out of a total average annual precipitation of 19.5 ’Schultz, C. B., and Stout, T. M., 1948, Pleistocene mammals and terraces in the Great Plains, in Colbert, E. H., ed., Pleistocene of the Great Plains: Geol. Soc. America Bull., v. 59, p. 570. ISOUTHERN ROCKIES AND PLAINS inches. This amounts to about 220,000 acre-feet of water annually, which is considerably more than the present rate of pumping. In Washington County, Colo., H. E. McGovern has found that the annual re- charge to the Ogallala formation is about 1 inch, which amounts to about 20 times the present rate of pump- ing. In Hamilton County, Nebr., where the annual precipitation is about 24 inches, C. F. Keech has deter- mined that the recharge to the Pleistocene sand and gravel comprising the aquifer in that area is 1.4 inches. According to C. F. Keech (1961) the application of surface water for irrigation along the Platte Valley below McConaughy Reservoir in Nebraska has caused an abrupt rise in ground—water levels from Lincoln County to Kearney County. Keech reports that the rise in water level exceeds 50 feet in one area in Phelps County and that the ground-water divide between the Platte and Republican Valleys has shifted southward several miles as a result of the rise. Ground-water storage In the Frenchman Creek basin above Palisade, Nebr., W. D. E. Cardwell and E. D. Jenkins calculate that the Ogallala formation contains about 81,000,000 acre- feet of ground water in storage. This is about 3 times the capacity of Lake Mead—the largest man—made lake in the United States. W. G. Hodson and K. D. Wahl (1960) report 1,200,000 acre-feet in storage in the Ogallala in northern Gove County, Kans. C. F. Keech reports about 9,000,000 acre—feet in storage in Pleisto— cene deposits in Hamilton County, Nebr.—enough to form a lake 26 feet deep over the entire county. Buried channels Buried channels of sand and gravel that are capable of yielding large quantities of water to wells have been located by geologic mapping and by test drilling in east- ern Colorado and southeastern Wyoming. A deep narrow gravel-filled channel has been reported by D. A. Coffin in the upper reaches of Big Sandy Creek valley above Limon, Colo., and a major buried channel along the Arkansas Valley having a depth of more than 200 feet in places has been traced by P. T. Voegeli in Prow- ers County. In the Wheatland area in southeastern Wyoming, E. P. Weeks reports that additional drilling has revealed the presence of coarse channel deposits of sand and gravel within the finer materials character- istic of the Arikaree formation in that area. Irrigation wells that penetrate the coarse materials generally will yield 50 to 100 percent more water than the wells that penetrate only the finer materials. A—29 Hydrogeology of Denver metropolitan area G. H. Chase and J. A. McConaghy have found that the principal recharge area for the Arapahoe formation in the Denver basin is in the southern part of the basin and that the water moves into the formation through a part of the Dawson arkose. They report that develop- ment of scattered pumping centers coincident with the growth of the metropolitan area has created numerous cones of depression in the piezometric surface and a gradual expansion of the area of declining pressure heads in wells tapping the formation. Heads have recovered somewhat in the downtown area in the cen- ter of the 7 7-year-old cone of depression. Chase and McConaghy also report the discovery of significant new aquifers in the Dawson arkose in some parts of the area. Some aquifers in the Dawson arkose yield water high in radon. Inversions of geothermal gradients occur between the Fox Hills sandstone and the Laramie formation, and also between the Laramie formation and the Arapahoe formation—Dawson arkose. Relation of ground-water quality to bedrock In the High Plains in parts of Cheyenne and Kiowa Counties, 0010., A. J. Boettcher has found that the quality of the water in the Ogallala formation difl'ers according to the bedrock beneath the Ogallala. Where the Ogallala is underlain by the Smoky Hill marl mem- ber of the Niobrara formation, the ground water has a significantly higher concentration of sulfate and chloride than where it is underlain by the Pierre shale. Ground-water development in New Mexico Data collected by H. O. Reeder and others (1960a) indicate that as of 1956, 855,000 acres of land were un- der irrigation in New Mexico. Of this area, 440,000 acres were irrigated with ground water alone, 130,000 acres with a combination of ground water and surface water, and 285,000 acres with surface water alone. The irrigation with ground water involved the pumping of 1,320,000 acre-feet of water with the result that ground- water levels reached record lows in most areas except in parts of the Roswell basin and the Carlsbad area. Distribution of moisture in soil and near-surface tufi In conjunction with work on the Pajarito Plateau, N. Mex., for the Los Alamos Scientific Laboratory, J. H. Abrahams, J r., J. E. Weir, and W. D. Purtymun (Art. 339) have shown that little, if any, water perco- lates through the soil mantle into the underlying rock. Using a neutron-scattering probe, they determined dur- ing a 99~day infiltration experiment that the moisture content of the soil decreased with depth from a maxi- mum of about 38 percent by volume in the B zone to A—30 less than 4 percent within a foot of the surface of the underlying tufl. Water apparently was perched on the C zone and the moisture content within the B zone approached saturation. COLORADO PLATEAU PROVINCE Most of the geologic studies on the Colorado Plateau have been undertaken to aid in the search for uranium, but may have application to petroleum exploration. Most of the hydrologic studies have been undertaken to aid in locating supplies of potable water for the small communities in the area. This work contributes to a broader understanding of the regional geology and hy- drology. Some of the findings of regional significance made during the fiscal year 1961 are summarized below. Results of work on mineral deposits in the region are reported on pages A—6 to A—7, and the results of work on geochemical prospecting are reported on page A—95. Stratigraphy Several geologists have reported new information on the stratigraphic relations of rocks of late Paleozoic and Mesozoic ages on the Colorado Plateau. Study of a small but good collection of vertebrate fossils by G. E. Lewis and P. P. Vaughn permits correlation of the up- per part of the Cutler formation near Placerville, Colo., with the Wichita group of Texas (Wolfcamp) and parts of the Autunian and Rotliegende of western Europe, all of Early Permian age. Of interest in con- nection with the correlation of Permian strata are the dominant directions of dip of the foreset beds in the thick crossbedded sandstones of the south-central part of the plateau province. C. B. Read and A. A. Wanek (Art. 206) report that there are two preferred direc- tions: (a) southeast to east in the Meseta Blanca sand- stone member of the Yeso formation (Zuni Mountains), the lower part of the DeChelly sandstone (Defiance Plateau), and the Cedar Mesa sandstone member of the Cutler formation (Monument Valley); and (b) south to southwest in the Glorieta sandstone (Zuni Moun- tains), the upper part of the DeChelly sandstone (Defi— ance Plateau), DeChelly member of the Cutler forma- tion (Monument Valley), and Coconino sandstone (near Holbrook and Winslow, Ariz.). In Triassic rocks studied by F. G. Poole (Art. 199), dip orientation of cross strata record a shift of the regional drainage direction from northwesterly in Moenkopi and early Chinle time to southwesterly dur- ing deposition of the upper part of the Chinle, Kayenta, and upper part of the Moenave formations. Age assignments of formations of the Glen Canyon group have been revised by G. E. Lewis, J. H. Irwin, and R. F. Wilson. The new assignments, adopted for use by the Geological Survey, are as follows: GEOLOGICAL SURVEY RESEARCH 1961——.SYNOPSIS OF RESULTS Navajo sandstone—Jurassic and Triassic( ‘9) Kayenta formation—Triassic( '4) Moenave formation—Triassic( ’9) Wingate sandstone—Triassic The Navajo sandstone is reported by J. C. Wright to thin to zero on salt anticlines in eastern Utah and west- ern Colorado, to thicken to as much as 700 feet in the intervening synclines (more than twice the normal regional thickness), and to extend in a continuous thinned belt northwesterly along the Cane Creek anti- cline to Bartlett Flat, 12 miles beyond the Colorado River. According to L. C. Craig, a sandstone like the uranium-bearing “J ackpile sandstone” is present at the top of the Morrison formation in the eastern part of the San Juan Basin, and at Bernalillo and Santa Fe, N. Mex, and may be present as far east as Las Vegas, N. Mex. R. A. Cadigan reports that the sandstone of the uranium-bearing Morrison formation (Late Jurassic) of the Colorado Plateau is composed of sodic tufl and ash, quartz, and sodic feldspar derived from the north- west; quartz and grains of silicified rocks derived from the west; quartz, fragments of silicified rocks and po— tassic tufl' derived from the southwest; and quartz, potassic and sodic feldspar, potassic and sodic ash and tufl', and granite derived from the south and southeast. Igneous rock sources contributed 50 to 75 percent of the constituent detritus; extrusive igneous rocks alone contributed 30 percent or more. New paleontologic evidence and stratigraphic corre— lations by C. H. Dane (1960a) suggest that much of the so-called Dakota sandstone of the eastern San Juan Basin may be of Late Cretaceous age, and therefore younger than the Dakota of northeastern New Mexico, which is entirely of Early Cretaceous age. The two areas may have been separated by an erosional barrier 15 to 25 miles wide extending southward along the 106° meridian toward central New Mexico. Dane also calls attention to bentonite beds clustered near the horizons of lithologic changes from Dakota sandstone to Graneros shale, from Graneros to Green- horn limestone, and from Greenhorn to Carlile shale. The bentonite beds may be widely useful in establish— ing regional correlations. They also suggest that more concentrated volcanic activity coincided with the epeiro- genie or climatic changes that produced the changes in lithology at formation boundaries. Paradox basin J. E. Case and H. R. Joesting (Art. 393) report aeromagnetic and gravity anomalies that indicate major northeast structural trends transverse to the dominant northwest trend of the late Paleozoic and Laramide COLORADO PLATEAU PROVINCE structure of the Paradox basin and Uncompahgre up- lift. The most prominent of the inferred basement structures are two inferred faults that cross the Monu- ment upwarp and Blanding basin and bound a zone of low density and generally low magnetization 20 miles wide and 50 miles long. Other northeast-trending structures parallel the Colorado River near Moab and Cisco, Utah, and another extends from the La Sal Mountains to Gateway, Colo. The intrusive rocks of the Abajo and La Sal Mountains lie at the intersections of northeast- and northwest-trending basement structures. Potash-bearing salts of the saline facies of the Para— dox member of the Hermosa formation are about to be developed commercially. R. J. Hite (Art. 337) reports that the saline facies extends over approximately 11,000 square miles, two—thirds of which is underlain by potash salts. The saline facies consists of 29 evaporite cycles of carbonate, gypsum, and salt deposits, of which about 18 contain potash salts and 11 contain potentially val- uable potash deposits from 1,700 to 14,000 feet below the surface. At present these deposits are considered to be minable only in the salt anticlines where they lie at the shallower depths. Recent exploration has been concentrated on nonintrusive folds, such as the Cane Creek anticline; information concerning the intrusive folds is still meager. Studies by E. R. Landis, E. M. Shoemaker, and D. P. Elston (Art. 197) demonstrate that growth of the Gypsum Valley salt anticline took place between Middle Pennsylvanian and Late Cretaceous time. Geomorphology and physiography Studies in northeastern Arizona by M. E. Cooley and J. P. Akers (Art. 237) show that four cycles of erosion, representing about 4,000 feet of downcutting, occurred throughout Miocene, Pliocene, and Pleistocene time in the Little Colorado drainage system of Arizona and New Mexico. Contours on the oldest surface at the base of the Bidahochi formation show that an en- trenched, integrated drainage system of the ancestral Little Colorado River flowed generally westward and northwestward during Miocene and Pliocene timef Unaweep Canyon, a wind gap in Precambrian crystalline rocks of the Uncompahgre plateau, is inter- preted by S. W. Lohman (Art. 60) to have been carved by the ancestral Colorado River and to have been abandoned after successive captures of the ancestral Colorado and Gunnison Rivers by a subsequent tribu- tary cutting in soft shale around the nose of the north- westward—plunging Uncompahgre arch. A—3 1 Hydrologic studies Geologic and ground-water studies in the Colorado Plateau by D. A. Phoenix (Art. 195) classify the thick and varied sequence of rocks into 7 hydrogeologic units. Unit 1, alluvium of Quaternary age, yields water in places. This water is locally contaminated by the activities of man. Units 2, 3, and 5 are shales of Tertiary, Cretaceous, and Triassic ages, which cover more than one—half the region; they are mostly non- water-bearing, and yield large amounts of dissolved solids and clay. Unit 4, sandstones of Triassic and Jurassic ages, yields water suitable for many uses, but the sandstones also yield large amounts of sandy sedi- ment. Unit 6, mostly limestone and shale of Paleozoic age, locally yields significant amounts of brine but in other places is similar to unit 4. Unit 7, igneous rocks of Tertiary age and basement rocks of Precambrian age, yields excellent water; these rocks crop out mostly in mountainous areas. In the Grants-Bluewater area, Valencia County, N. Mex., the Glorieta sandstone and the overlying San Andres limestone, of Permian age, are the principal aquifers. Alluvium and interbedded basalt of Quater- nary age form an aquifer of secondary importance. E. D. Gordon reports that most large-capacity wells in the area pump from the San Andres, and where the hydraulic pressure in the San Andres has been de- creased, water has moved from the Glorieta into the San Andres. The use of ground water between 1950 and 1957 was stabilized at about 13,000 acre-feet per year. Withdrawal of ground water has caused water levels to decline 40 to 45 feet north of Bluewater Vil— lage, and 18 to 20 feet from Bluewater Village south- east to near Grants. Yields of irrigation, industrial, and municipal wells range from 500 to 2,200 gpm. Gen- erally, the water is suitable for irrigation, although the salinity is high locally. At some places the sulfate con- centration is high enough to impart an objectionable taste to the water. In the Ashley Valley oil field, Uintah County, Utah, R. D. Feltis and H. D. Goode (Art. 184) report that the comparatively fresh oil-field water, which contains only 500 to 2,000 ppm total solids, is being used for irrigation. This use is made possible by the fact that deleterious components of the water are neutralized by components of the soil. The oil and associated water are derived from the Weber sandstone of Penn- sylvanian age. The water drive for the oil is probably sustained by surface recharge in outcrop areas north and east of the field. According to S. W. Lohman, the principal artesian aquifers in the Grand Junction area, 0010., are the A—32 “ l Entrada sandstone of Jurassic age and the Wingate sandstone of Triassic age. Recharge to them occurs a short distance southwest of town where they are ex- posed along the Redlands fault and associated mono- clines. (The artesian wells normally yield 5 to 25 gal— lons per minute. Between Grand Junction and the out- crop area, the ground water is of a sodium bicarbonate type excellent for domestic use. Where the water-bear- ing beds are deeper and farther from the outcrop, as is the case northeast of Grand Junction, the water con- tains more dissolved solids and is therefore less useful. Detailed lithologic studies of Navajo sandstone in the Copper i Mine-Preston Mesa area, Coconino County, Ariz., by N. E. McClymonds (Art. 321) show that up— warping accompanied deposition of the Navajo sand- stone. Ground water is absent on the higher parts of the upwarp but occurs on its flanks. Locally it occurs near the‘, crest, in a tongue of the Navajo sandstone underlying a tongue of the Kayenta formation. J. P. Akers and P. E. Dennis report that additional ground Water for the town of Flagstaff, Ariz., may be obtained \from glaciofluvial sediments in the Inner Val- ley on san Francisco Mountain, Coconino County, and from permeable zones along several large normal faults. i Injection tests at the Bluewater uranium mill of the Anaconda Co. at Grants, N. MeX., indicate to S. W. West that sediment-free mill afliuent can be charged into the lower part of the Yeso formation through an 8-inch well at the rate of more than 380 gpm but less than 1,000 gpm. Studies of ground water in alluvium along the} Colorado and Gunnison Rivers in western Colorado by D. A. Phoenix show that this water locally contains betWeen 20 and 40 ppm nitrate, expressed as N03. The nitrate probably originates from nitrog- enous fertilizers used in farming. \BASIN AND RANGE PROVINCE l Geologid and hydrologic investigations in progress in the Basin and Range ProVince have yielded important new information in structural and stratigraphic geol- ogy, volcariology, and hydrology as summarized below. Additional information is given on other pages as follows: mineral deposits, pages A—l to A—8; paleontol- ogy, pages A—59 and A—60; geophysical work, pages A—69 to A—7 1; evaporite deposits, page A—7 6; work at the Nevada Test Site, pages A—90 to A—91; geochemical prospecting, page A—95; Pleistocene lakes, page A—11; and Pleistocene climate, page A—87. Thrust faults in Nevada and Utah In central and eastern Nevada, interpretations of the complex thrust fault problems depend in large part upon interpretations of stratigraphic relations. R. L. GEOLOGICAL SURVEY RESEARCH-I 1961—SYNOPSIS OF RESULTS Erickson and A. P. Marranzino, working in conjunc- tion with Harold Masursky, have found evidence that the three previously defined facies of Paleozoic rocks in the region—the eastern, transitional, and western facies—have distinctive metal contents. Preliminary results suggest that western facies siliceous rocks are rich in metals, particularly in vanadium, copper, bar- ium, and titanium, whereas eastern facies rocks are poor in metals. This evidence suggests that rocks in the Cortez quadrangle, Nevada, previously thought to be eastern facies and part of the lower plate of the Roberts Mountain thrust fault, may be transitional or western facies and part of the upper plate. In the southern Diamond Mountains of eastern Ne- vada, D. A. Brew (Art. 191) has found that the Chain- man shale on the upper plate of the Bold Bluff thrust fault is 3,500 to 4,000 feet thick and is composed of silt- stone, claystone, and sandstone; whereas on the lower plate it is 2,500 feet thick and is composed of black shale. Mapping by T. B. Nolan and C. W. Merriam in the Lone Mountain area of eastern Nevada shows that the principal structural feature is a window. The main mass of Lone Mountain is composed largely of eastern facies carbonate rocks ranging in age from Ordovician to Middle Devonian. Pediments on the flanks of Lone Mountain reveal rocks of the upper plate, including graptolitic shale and chert belonging to the Vinini formation of Ordovician age, associated with fusulinid- bearing strata of the Garden Valley formation of Per- mian age. An analysis by M. D. Crittenden, J r., (Art. 335) of the thicknesses of three groups of Paleozoic rocks in northern Utah indicates displacements of about 40 miles across a belt of overthrusts, including the Bannock, Willard, Charleston, and Nebo faults. The overriding blocks moved relatively eastward. The analysis does not rule out even larger displacements. In contrast, in the Kings River Range area of northwestern Nevada, C. R. Willden (Art. 192) has found thrust fault rela— tions that indicate westward overriding of at least 40 miles, so that nonmetamorphosed rocks of Permian to Middle Triassic age rest on metavolcanic rocks of prob- able Permian or older age. In southwestern Utah, D. M. Lemon and H. W. Sundelius mapped the upper plate of the Frisco thrust from Frisco Peak northeast for 21 miles. Six windows of lower plate rocks of late Cambrian and Ordovician ages are exposed in the San Francisco Mountains as far as 9 miles northeast of Frisco Peak, but none was ob- served farther north in the Beaver Mountains. Other structural features R. K. Hose has found through detailed mapping that the Confusion Range of western Utah was the site BASIN AND RANGE PROVINCE of a large structural trough at the end of the late Meso- zoic orogeny. He has determined that the flanks of the trough had average slopes of as much as 19 degrees, and he believes that this relief coupled with contrasts in competency of rocks involved accounts for the dif- ferent tectonic styles displayed by rocks in the area. Relatively competent lower Paleozoic rocks are char- acterized by broad open folds and homoclines, whereas incompetent upper Paleozoic and Triassic rocks show complex disharmonic folds and thrust faults. Recent studies of ancient Lake Bonneville shore lines in western Utah by Crittenden (1960) support G. K. Gilbert’s conclusion of 1890 that the increase in eleva- tions of these shore lines since Pleistocene time is the result of isostatic rebound after unloading. The maxi- mum deflection of 210 feet indicates that isostatic com- pensation for removal of the load is at least 70 percent of the theoretical maximum, and may be virtually complete. ,‘ A northwaer trending elongate dome about 40 miles wide and 80 iles long is centered roughly between the Snake an Deep Creek Ranges, Nev., according to structural ana‘lysis by H. D. Drewes (1960) . The dome has been striongly modified by near-bedding-pl-ane thrust faults (and complex north-trending structures. T. W. Dibb ee, Jr. (Art. 82) has found that many of the northwest-trending high—angle faults of Quaternary age in the western Mojave Desert region show evidence of right-lateral displacement, in the same sense as the San Andreas fault. This type of displacement is in— dicated by the offset of contacts and fold axes, by east- trending drag folds associated with the faults, and by north-trending tension fractures. Geologic mapping by G. I. Smith (1960) along the Garlock fault, southeastern California, has shown that two large dike swarms that crop out 40 miles apart on opposite sides of the fault are similar and probably represent ofl'set segments of the same swarm. The swarms were probably intruded during late Mesozoic time, just before movement of the fault began, and the present separation of 40 miles approximates the total left-lateral displacement on the fault. Studies of Cambrian and Precambrian rocks Recent geologic mapping by M. H. Krieger (Art. 207) in the northern end of the Galiuro Mountains of southeastern Arizona has shown that rocks formerly called Troy quartzite and considered to be of Cambrian age actually include two units, one of Precambrian and the other Cambrian age, separated by a major un- conformity. The unit of Precambrian age, to which the name Troy quartzite is now restricted, was intruded by diabase sills before deposition of the unit of Cam- A—33 brian age, which includes the Bolsa quartzite and the Abrigo formation. In central Arizona, A. F. Shride has found that an extensive karst topography was developed on dolomite of the Mescal limestone of Precambrian age, both be- fore and during deposition of the overlying Troy quart- zite. The dolomite was thoroughly silicified during the period of weathering, and locally a highly fer- ruginous regolith was formed. In sandstone overlying the Precambrian in the Min- gus Mountain-Jerome area, central Arizona, heretofore regarded as Tapeats( ?) formation (Cambrian) by some geologists and as basal Devonian by others, Curt Teichert discovered a bed crowded with U-shaped bur— rows of the Uorophioides type. Occurrence of these trace fossils removes doubts as to the correlation of this sandstone with the Tapeats, because they occur abund- antly in undoubted Tapeats sandstone of Juniper Mesa, the Chino Valley, and the Grand Canyon. A. R. Palmer has found from a study of Lower Cam- brian faunas and their distribution that the names Stirling and Prospect Mountain for Lower Cambrian quartzites of the Great Basin are not merely different geographic designations for parts of a simple eastward time-transgressive quartzite series. The Prospect Mountain quartzite is at least in part a regressive quartzite with its thin western edge represented by the Zabriskie quartzite member of Hazzard 1° of the Wood Canyon formation, several thousand feet stratigraphi- cally above the Stirling quartzite. New data on Cretaceous rocks Along the east side of the Cortez Range, Pine Val- ley quadrangle, Nevada, a sequence of nonmarine rocks mapped by J. F. Smith, Jr., and K. B. Ketner and previously considered to be of Tertiary( ?) age, is now known on the basis of studies of plant and pollen to be of Cretaceous age. Plants collected from these beds have been dated as Cretaceous by J. A. Wolfe, and pollen have been dated as Early Cretaceous or early Late Cretaceous by E. B. Leopold. The sequence rests on volcanic rocks which must, therefore, be of Cretaceous age or older. In the southern extension of the Pifion Range, 10 miles east of the above locality, nonmarine rock in a small area contains ostracodes which have been de- termined by I. G. Sohn to be of probable Early Cretaceous age. Emplacement and age of intrusive bodies The Climax stock, Nevada Test Site, Nye County, has been found by F. N. Houser and F. G. Poole (Art. 1° Hazzard, J. C., 1937, Paleozoic section in the Nopah and Resting Springs Mountains, Inyo County, Calif.: California Jonr. Mines and Geology, v. 33, no. 4, p. 273—339. A—34 73) to be made up of an older granodiorite and a younger quartz monzonite. Ages of 230 and 330 mil- lion years have been determined by the lead-alpha method for the quartz monzonite. The lesser age is in better accord with geologic evidence. (See also p. A—91.) Tertiary volcanic rocks and calderas Aided by criteria established largely by R. L. Smith, (1960a, b) several large, heretofore unknown calderas have been recognized in the Basin and Range Province. In southwestern Nevada, west of Beatty, H. R. Corn- wall and F. J. Kleinhamphl (1960a, b) have delineated the Bullfrog Hills caldera, which is about 15 miles in diameter. Another probable caldera, about 10 miles in diameter, occupies Yucca Mountain to the east of Beatty. Northeast of these two, in the vicinity of Tim- ber Mountain, a large caldera has been recognized through work by F. A. McKeown, E. N. Hinrichs, P. P. Orkild, and others in collaboration with R. L. Smith. This caldera measures at least 18 miles in diam- eter and is responsible for rather conspicuous ringlike topographic features around Timber Mountain. Oligo- cene( '9) welded tufl's about 8,000 feet thick were found by Harold Masursky (1960) in the northern Toiyabe Range, Nev., in a fault—bounded trough, perhaps a volcano—tectonic depression, about 10 miles wide and 50 miles long in an east-west direction. D. R. Shawe (Art. 74) has discovered that two rhyo- litic rocks of Tertiary age in the Egan Range of eastern Nevada are superficially similar but are chemically and petrographically distinct, and probably were not derived from the same magmatic source. One, an in- trusive rhyolite confined principally to a volcanic neck about one mile in diameter, contains 73.5 percent silica and 13.6 percent alumina. The other, a welded tufl', contains 69.7 percent silica and 14.1 percent alumina as well as several times as much iron oxide, magnesia, lime, and titania as the intrusive rhyolite, and less soda and potash. In the Klondyke quadrangle, Arizona, F. S. Simons has found that the Copper Creek breccia pipes are lined along a vaguely defined northwest trend that may reflect a buried elongate body of biotite latite. Geologic mapping by J. R. Cooper in the Twin Buttes quadrangle and other parts of southeastern Arizona has established that a distinctive volcanic rock known locally as the “turkey-track porphyry” occurs as flows and dikes in at least 10 neighboring mountain ranges. At one place the rock is enclosed in beds of probable early Miocene age. The rock ranges in composition from olivine-augite—plagioclase porphyry to hyper- sthene—augite-plagioclase porphyry. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS D. W. Peterson (Art. 322) reports that the degree of flattening of pumice fragments in an ash-flow sheet near Superior, Ariz., increases progressively downward. This indicates that ash flows erupted in such rapid suc- cession that the sheet formed as a single cooling unit. The difference in flattening ratios on opposite sides of faults can be used to estimate stratigraphic throw. Quaternary history Ronald Willden and D. R. Mabey (1961) have discov- ered giant dessication cracks in the playa deposits of the Black Rock Desert and other basins of western Ne- vada. The cracks form large polygons, several hun- dred feet on a side, and probably resulted from the desiccation to unusual depths of playa sediments, thus suggesting a period of years of extreme dryness. R. B. Morrison (Art. 330) has suggested that the boundary between the Pleistocene and Recent (Holo- cene) in the great Basin region be placed at the top of a distinctive soil (the post-lake Lahontan soil), the type area of which is the Carson Desert, Nev. East of the Funeral Mountains, Calif, C. S. Denny (Art. 323) has mapped landsides, in large part highly brecciated sheets of limestone (megabreccia), that moved along gullies out onto the pediment. Ground-water occurrence and movement in pre-Tertiary rocks Studies of ground—water systems in intermontane basins of the Basin and Range Province indicate that (a) ground-water moves locally from one intermontane basin to another through pre-Tertiary bedrock forma- tions; (b) pre-Tertiary bedrock may play an important role in ground-water circulation within a closed or _ nearly closed basin; and (c) Tertiary formations under- lying Quaternary alluvium in valleys have an impor- tant role in the storage, recharge, and development of ground water. Studies in the Nevada Test Site by I. J. Winograd show that the regional water table is generally deep below the Quaternary alluvium and commonly is in the Oak Spring formation, which underlies the alluvium. The slope of the regional water table in the Oak Spring formation is very gentle, and ground-water movement is slow. From observations of the discharge of Ash Meadow and other springs in the area southwest of the Nevada Test Site, together with water-level and chemi— cal data from wells in adjoining areas, 0. J. Loeltz (1960b) has concluded that ground water moves in pre-Tertiary formations between valleys. T. E. Eakin reports that the White River drainage system of eastern Nevada contains numerous springs that issue from Paleozoic limestone. These occur in four general areas—between Preston and Sunnyside, in Pahranagat Valley, near the mouth of Arrowhead COLUMBIA PLATEAU AND Canyon, and northwest of Moapa. The springs in Pahranagat Valley and near the mouth of Arrowhead Canyon discharge about 35 cfs (cubic feet per second) and 40 to 45 cfs, respectively. These volumes are rela- tively large as compared with the drainage areas and suggest that considerable inflow occurs through pre- Tertiary bedrock from outside the topographic drain- age area. Some of the inflow may come from Long Valley, which is 30 to 40 miles northwest of the head- water area of White River Valley. A substantial part of the ground water in Long Valley apparently is being discharged through pre—Tertiary bedrock, and geologic trends and potential hydraulic gradients suggest that it is moving generally southward toward the White River Valley. Hydrogeochemistry Philip Cohen has concluded that the uranium content of the waters of Truckee Meadows, near Reno, Nev., is not by itself an important aid in evaluating the hydrogeochemistry of the area. Forty-seven samples of water were analyzed for uranium and many other chemical constituents. It was found that (a) uranium content tends to increase as the bicarbonate-carbonate concentration increases; (b) thermal chloride-rich waters associated with Steamboat Springs are rela- tively deficient in uranium; and (c) some waters high in sulfate are relatively rich in uranium, but others are not. The complex geology, the complex interrelation- ships among chemical and radiochemical constituents of the waters, and the wide variations in concentration, all affect the movements of uranium. Specific yield of sediments Philip Cohen (Art. 164) reports that the specific yields of fine-grained sediments from the Humboldt River Valley in the vicinity of Winnemucca, Nev., are exceptionally high, due in part to the efl’ects of second- ary porosity. The mean specific yield of 209 samples is 21 percent. The specific yields were determined by the centrifuge-moisture-equivalent method. The values for specific yield are useful for estimating ground- water storage capacity but cannot be used for eval— uating short-time changes in ground-water storage. Floods and mudflows Studies in Utah under the direction of V. K. Ber- wick indicate that in drainage basins where the runoff is principally snowmelt the ratio of the mean annual flood to the 50-year flood is about 1 to 2. In basins where runoff is from cloudbursts, the ratio is about 1 to 6. The data also suggest that highest rates of pre- cipitation occur at intermediate rather than higher altitudes in the Basin and Range Province. As the long intervals between cloudburst floods provide time SNAKE RIVER PLAINS A—35 for the accumulation of soil and debris, high-intensity rains of short duration may result in mudflows. A mudflow that occurred in Kings Canyon, on the east slope of the Sierra Nevada near Carson City, Nev., on July 30, 1960, was estimated by L. J. Snell to contain about 320,000 cubic feet (7.4 acre-feet) of material, including boulders 2 feet or more in diameter, and short logs as much as 2 feet in diameter. Peak discharge probably did not exceed 150 cfs. A cloud- burst within a drainage area of 1.2 square miles and between altitudes of 5,300 and 8,500 feet, caused the mudflow. COLUMBIA PLATEAU AND SNAKE RIVER PLAINS Studies of stratigraphy and geologic history in the Columbia River Plateau and Snake River Plains are concentrated in the John Day region of Oregon and the Snake River Plains of southern Idaho. Studies of water resources include work on discharge in the Co- lumbia River basin, quality of ground water in the eastern Snake River Plains, and ground-water hydrol- ogy of basalts in several parts of the Columbia Plateau and the Snake River Plains. Other hydrologic work in the region is summarized on pages A—39 to A—40, A—92, and A—93 to A—94. Laumontite stage metamorphism of Upper Triassic rocks, Aldrich Mountains, Oregon In a comprehensive study of the mineralogy of the thick Upper Triassic sequence of bedded rocks in the Aldrich Mountains of Oregon, C. E. Brown (Art. 201) found an authigenic mineral assemblage characteristic of the zeolite metamorphic facies. The mineralogic observations support the inference previously drawn from field studies that these rocks were deformed dur- ing deposition in Late Triassic time. Most of the rock types in the section (graywacke, shale, mudstone, tufl', pillow lava, and volcanic graywacke) contain authigenic albite, quartz, chlorite, sphene, epidote, and leucoxene, but the rock types all or partly of volcanic origin are characterized by laumontite, prehnite, pum- pelleyite, and celadonite. These minerals grew in an environment of increased pressure and temperature that possibly resulted from depth of burial and (or) tectonic folding not long after deposition of the rocks. Stocks of Cretaceous age had notable local contact effects, but had little regional influence on the assem- blage of authigenic minerals. Facies changes in the John Day formation In the vicinity of Ashwood, Oreg., a section of the John Day formation described by D. L. Peck (Art. 343) is about 4,000 feet thick and is made up dominantly of more or less welded ash flows, lava flows, and abundant beds of lapilli tufl', in marked contrast to the fine tufl' A—36 and tufi'aceous claystone of the type section about 50 miles east at Picture Gorge. These newly described rocks are in or near the area of their source vents. Volcanic ash falls used as stratigraphic marker beds H. A. Powers and H. E. Malde (Art. 70) have used chemical and mineralogical techniques to identify beds of volcanic ash in widely separated exposures of sedi— mentary deposits in the western Snake River Plain, so as to correlate stratigraphic sections of dissimilar lith- ology and to determine amounts of basin deformation. For example, chemical comparisons by Powers (Art. 111) show that the amounts of chlorine and fluorine in different ash deposits are different in most examples, although the amounts are nearly equal in various sam- ples from the same ash deposit. V Gravity anomalies The study of gravity in the western Snake River Plains now extends from the Oregon line eastward to Twin Falls, Idaho. D. P. Hill, H. L. Baldwin, Jr., and L. C. Pakiser (Art. 105) suggest that 3 elongated en echelon gravity highs found under the western part of the plain may be due in part to basalt-filled major fissures in the crust. New data on the age of the Columbia River basalt K. E. Lohman has determined that the upper part of the Columbia River basalt (Yakima basalt) is of early Pliocene age on the basis of diatoms collected by A. C. Waters. This confirms previous determinations based on fossils of vertebrates and fresh-water mollusks. Southward transgressive overlap of the basalt Near the southern margin of the Columbia River basalt plateau, in the Monument quadrangle, Oregon, the persistent occurrence of basaltic breccia and related rock-forms at the base of the basalt on dissected rocks of the John Day formation is ascribed by Ray E. Wilcox to flow-by—flow encroachment up valleys and into lakes ponded by preceding flows. Landforms of Pleistocene age in the Snake River Plains H. E. Malde (Art. 71) finds that sorted nets, circles, and stripes occur on the dissected surfaces of various deposits of middle Pleistocene and older age in the west— ern Snake River Plains; these patterned features re— semble solifluction features of polar regions. Because this patterned ground is not found on the surface of deposits of late Pleistocene or younger age, it is con- sidered to be a fossil landform that developed under a former colder climate. Pleistocene American Falls lake and the Michaud gravel A study of the Michaud gravel near American Falls, Idaho, by D. E. Trimble and W. J. Carr (Art. 69) shows it to be a delta deposited in a Pleistocene Amer— GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS ican Falls lake by a large stream entering the lake through the Portneuf canyon. This ancient stream is G. K. Gilbert’s Bonneville River, the outlet of Pleisto- cene Lake Bonneville. Carbon-14 analyses show that the Michaud gravel delta is more than 30,000 years old. Other Pleistocene drainage changes A study by D. W. Taylor (1960) may supply further evidence that the Snake River system was joined to the Columbia River system comparatively recently, and that the Snake River formerly drained other areas in Oregon, California, and Nevada. Taylor reports that Pliocene and Pleistocene remains of Pisidz'mn ultramonbanum Prime, a freshwater clam that lives in northeastern Cali- fornia and south-central Oregon, occur in the rocks of the Snake River Plain as far upstream as southeastern Idaho. This occurrence, together with the distribution of several other relict mollusks and fishes, indicates for- mer drainage connections along a chain of basins ex— tending from Walker Lake in western Nevada across Eagle Lake and the upper Pit River, Calif., to Klamath Lake in Oregon; thence across Fossil Lake and the Malheur Basin, Oreg., to the Snake River Valley; and through Gentile Valley and Bear Lake, Idaho, to Utah Lake in the Lake Bonneville Basin. Basin discharge studies K. N. Phillips has observed that the water levels of Davis Lake and East Lake in the Deschutes River basin were higher in 1957 and 1958 than they have been in many years. Trees 200 years old were being drowned in 1957 by the high waters of Davis Lake, and, in 1958, trees 50 years old were being drowned by high waters of East Lake. Runoff in the Oregon part of the Columbia Plateau has been considerably above normal during the period from 1942 to 1958. A method for predicting monthly and seasonal streamflow during the low-flow periods for many trib- utaries of the Columbia River has been devised by C. C. McDonald and W. D. Simons. The method takes into account data on base-flow characteristics, historical runoff, and selected levels of probability. In the Snake River basin of Idaho, studies by C. A. Thomas and others show that the magnitude of natural flood runoff at selected frequencies at any site may be forecast within reasonable limits by statistical exten- sion of data gathered on previous floods. The statis- tical method uses a formula that integrates locally derived factors for drainage area, precipitation, and geographic conditions. Cloudburst floods on August 20, 1959, from recently burned-over slopes near Boise, Idaho, were found by W. I. Travis and associates to have produced runofl' PACIFIC COAST REGION as great as 5,380 cfs per square mile from a. drainage area of 0.39 square mile. The volume of the flood reaching the lowlands was approximately 500 acre-feet, and the debris deposited on the lowlands was about 200,000 tons, or one ton of debris for each 3.4 tons of fluid. The transporting flood retained approximately the fluidity of water despite the mud-flow appearance of the deposited debris. Quality of ground water E. H. Walker has identified several distinct types of ground water beneath the eastern part of the Snake River Plains. These are (a) partly thermal waters, mainly of the sodium carbonate type but with some calcium-magnesium—bicarbonate, sodium chloride, and sulfate varieties, (b) meteoric waters, which are mainly calcium-magnesium-bicarbonate varieties and have smaller amounts of dissolved solids progressively_ toward the northern side of the plains, and (0) ground water mixed with returned irrigation waters which contain larger amounts of dissolved solids than the meteoric waters. Studies of uranium and radium in ground water in the Pacific Northwest are summarized on page A—83. Ground water in basalts The rubble present at the base and top of basalt flows is locally thick and continuous; such layers are impor- tant aquifers for the movement of ground water in the Columbia Plateau and Snake River Plain. Field studies by M. J. Grolier, utilizing data accumulated during previous investigations, show that several such major aquifers can be identified and traced throughout a large area of central Washington in the region of the Grand Coulee. Permeable basalt layers that dip be- neath the water table in Cow Valley of the Malheur River basin afl'ord high yields to wells (Foxworthy, Art. 203) and may be present and unused in many other places. Such layers are preferable to the over- lying permeable alluvium as a source of water because well construction is simpler, yields are higher, and the water is free of sand. R. C. Newcomb (Art. 88) found that synclines in the Columbia River basalt are the major areas of ground— water accumulation, and that sharp folds and strike faults are barriers that trap substantial reservoirs of ground water. In a study of the hydrology of radioactive waste dis- posal at the National Reactor Testing Station, Idaho, P. H. Jones (Art. 420) has found that important aqui- fers and sedimentary interbeds in the Snake River lavas can be identified and mapped locally by means of cali- per and gamma-ray logs; and that warm, saline dis- posal waste-water can be traced in lateral extent by 508400 0—61—~——4 A—37 temperature and resistivity logs. Subsurface informa— tion compiled by E. H. Walker for wells at the testing station shows that the top 1,000 feet of the predomi- nantly lava section contains interbedded sedimentary materials, largely in three zones. The position and ex— tent of the sediments indicate they were deposited in lakes impounded by the extrusion of lavas to the south- west. PACIFIC COAST REGION Investigations in the Pacific Coast region are grouped for discussion into the following categories: (a) Washington, (b) Oregon, (0) Klamath Mountains and Coast Ranges of northern California, ((1) coastal areas of central and southern California, (e) Sierra Ne- vada, and (f) hydrologic studies. Additional infor- mation pertinent to the region is summarized on other pages as follows: gold in California, page A—3; paleon- tologic studies, page A—60; geophysical studies, pages A—69 to A—70; and landslides in the Los Angeles area, page A—89. Washington Geologic mapping in King County by J. D. Vine and H. D. Gower and parallel studies of fossil plants by J. A. Wolfe (Art. 233) have distinguished seven floral zones that range in age from early Eocene to possible earliest Oligocene in the coal-bearing Puget group. Fossil plants have also been collected from the lower part of the overlying Keechelus andesitic series at scat- tered localities in the Cascade Range from Green River canyon, King County, south to Mount St. Helens. Floras from eight localities examined by Wolfe (Art. 232) are equivalent in age to the Keasey and Lincoln “stages” of the Oligocene. These floras and others from the Puget group indicate that the uppermost part of the Puget group in the Green River canyon area is correlative with the lowest part of the Keechelus far- ther south near Tacoma. D. J. Stuart (Art. 248) finds a close correlation be— tween gravity highs and basaltic volcanic rocks in wes- tern Washington. His bouguer anomaly map shows a continuous gravity high superimposed on the westward- opening U-shaped band of volcanic rocks around the Olympic Mountains; the map also shows very large negative anomalies near Seattle and Everett that indi- cate thick Tertiary sedimentary sections. Analysis of the anomalies suggests that the volcanic rocks, or asso- ciated dense crustal rocks, reach thicknesses of tens of thousands of feet. Oregon As part of a regional study of the stratigraphy and structure of Tertiary rocks in the Coast Range of Ore- gon, E. M. Baldwin has discovered a major structural A—38 basin on the lower Umpqua River near the town of Elk- ton. Near the center of the basin, rhythmically bedded sandstone of the middle Eocene Tyee formation, is overlain by several thousand feet of siltstone that has yielded abundant marine fossils of late middle or early late Eocene age. Overlying this siltstone with slight angular unconformity are plant-bearing beds of sand- stone, largely of continental origin, that are tentatively assigned to the Coaledo formation of late Eocene age. A detailed study of the marine mollusks of the Asto— ria formation of middle Miocene age in western Oregon by Ellen J. Moore supports the correlation of the Asto— ria with the Temblor formation in California (“Barker’s Ranch” fauna). Rocks dredged from the Coos Bay channel have yielded a Miocene fauna equiva- lent in age to the Astoria fauna. P. D. Snavely and H. C. Wagner (Art. 344) describe the widespread upper Oligocene gabbroic and alkalic sills that intrude Eocene- sedimentary and volcanic rocks of the Oregon Coast Range. Granophyric gabbro and diorite are the principal species in a differentiated suite of rocks similar chemically to the Skaergaard, but most of the sills are more alkalic in composition and compare closely to Nockolds’ average tholeiitic andesite. A layer of basalt 45 to more than 315 feet thick that underlies alluvium in COW Valley, Malheur County, Greg, is fractured along faults and is an important source of water for irrigation. According to B. L. Foxworthy (Art. 203), excessive pumping of this aquifer during the period 1951 to 1960 led to a pro- gressive lowering of the water table. His studies in- dicate that recharge to the drainage basin of about 60 square miles is about 5,000 acre-feet per year, which is about 2/3 of the yearly withdrawal. Klamath Mountains and Coast Ranges of northern California A geologic reconnaissance of the northern Coast Ranges and Klamath Mountains in California by W. P. Irwin (1960) shows that the Klamath Mountains com- prise four concentric arcuate belts, concave to the east, that include rocks ranging from the Abrams mica and Salmon hornblende schists of pre-Silurian age to metavolcanic rocks and slate of the middle Upper Jurassic Galice formation. West of the Klamath Mountains are the northern Coast Ranges, composed chiefly of graywacke and shale of the Franciscan forma— tion of Late Jurassic to Late Cretaceous age. (See also p. A—l.) E. H. Bailey (1960) has described the Franciscan formation as an ensimatic eugeosynclinal deposit that consists 80 percent of graywacke, 10 percent of siltstone and shale, 8 percent of mafic rocks, and the rest of conglomerate, limestone, chert, and glaucophane and GEOLOGICAL SURVEY RESEARCH lQfil—SYNOPSIS OF RESULTS related schist. Although the Franciscan is dominantly unmetamorphosed, it includes scattered rocks of the zeolite (laumontite), “blueschist”, and eclogite facies. On the basis of specific gravity determinations of over 1,000 specimens, W. P. Irwin (Art. 78) reports that the median specific gravity of sandstone in the Franciscan is 2.65, appreciably higher than the median specific gravity of sandstone in the Knoxville formation and formations of Cretaceous age in the Sacramento Valley. All specimens of graywacke in the Franciscan with a density above 2.71 contain minerals resulting from metamorphism, chiefly jadeite, pumpelleyite, and law— sonite. Assemblages of these and other minerals indi- cate that parts of the Franciscan have been subjected to high-pressure, low-temperature metamorphism of the “blueschist facies.” These conditions require a load of at least 70,000 feet of sediments, which could be attained in a rapidly filling and rapidly subsiding basin. It is inferred that the “blueschists” must have been up- lifted before a normal thermal gradient was established, as otherwise they would have been converted to greenschist. Studies by C. W. Merriam (Art. 216) of faunas from marine Silurian and Devonian strata in the eastern Klamath Mountains indicate that the Gazelle formation is of Silurian and Early Devonian age, and is partly correlative with Silurian rocks at Taylorsville and probably correlative with the Copley greenstone and Balaklala rhyolite, which underlie the Middle Devonian Kennett formation. Studies by G. D. Bath and W. P. Irwin of aerial— and ground—magnetic traverses across the northern Coast Ranges, Great Valley, and Klamath Mountains prov- inces of California show a close correlation between large positive anomalies and large bodies of ultramafic rock. The anomalies over ultramafic rock are com- parable in amplitude and character to the anomaly that extends for more than 300 miles along the central part of the Great Valley, suggesting that the Great Valley anomaly is caused by a buried mass of ultramafic rock. In a complexly faulted block along the boundary be- tween the Sacramento Valley and the Coast Ranges, R. D. Brown, J r., and E. 1. Rich have found that strata previously regarded as Franciscan are sandstone and interbedded mafic volcanic rocks of the Knoxville formation. Coastal area of central and southern California A stable shoreline persisted in the area of the Caliente Range, Calif, from early to late Miocene time, and an exceptionally thick continuous sequence of highly fossiliferous intertonguing marine and continental strata was deposited. Several basalt flows in the PACIFIC COAST REGION sequence extend from marine to continental rocks, pro- viding distinctive lithologic and time horizons. On the basis of faunal studies and detailed mapping in the eastern part of the Caliente Range, C. A. Repenning and J. G. Vedder (Art. 235) have correlated mammalian faunas representing three North American provincial ages (as defined by Wood and others) with marine mollusk faunas of Miocene age. The Arikareean (mam— malian) age is at least in part correlative with the early Miocene as defined by marine mollusk faunas, and the upper limits of these two faunal ages are essentially identical. The Hemingfordian (mammalian) fauna is entirely equivalent to part of the middle Miocene marine mollusk fauna. The Barstovian (mammalian) fauna is in part correlative with middle Miocene and in part equivalent to probable late Miocene marine mollusk faunas. Clarendonian and Hemphillian mammalian faunas occur in the upper part of the continental strata, but equivalent Miocene and Pliocene marine beds are not known in the area. In the western part of the Puente Hills, R. F. Yerkes has mapped a 10-mile-wide band of steeply plunging folds along the north side of the Whittier fault that, on physiographic evidence, has long been considered a strike-slip fault. The folds decrease in plunge from 75° in the west to about 35° in the east. Interpretation of the folds as drag folds along the fault suggests that right-lateral strike slip dominated at the western end of the fault, and reverse dip slip in the eastern part; in both places a net slip of about 15,000 feet is indicated. Studies by J. G. Vedder of large assemblages of marine mollusks from the lowest emergent terrace in the San Joaquin Hills area, southern California, pro- vide evidence of complex local paleoecologic conditions during late Pleistocene time. Between San Clemente and Corona del Mar vigorous upwelling locally cooled surface waters that were warmer than at present. Sur- face-water temperatures were even higher east of the present upper Newport Bay, in the protected eastern part of the ancestral Newport Lagoon. Mollusks from the West Newport oil field include species characteristic of various habitats and temperatures; this mixture sug— gests the effects of current transportation, incursions of fresh water, and reworking of older faunas. Late Jurassic fossils have been identified from two localities in pre-granitic rocks in the Santa Ana and Santa Monica Mountains of California. In the Santa Ana Mountains, J. E. Schoellhamer and N. J. Silber- ling of the US. Geological Survey, and C. H. Gray of the California Division of Mines, collected ammonites from the Bedford Canyon formation that have been identified by R. W. Imlay as Callovian (early Late Jurassic) in age. The Santa Monica slate in the Santa A—39 Monica Mountains has yielded pelecypods identified by Imlay as species of Buchia of late Oxfordian to Kim- meridgian (middle Late Jurassic) age. Sierra Nevada Comparison by P. C. Bateman and J. G. Moore of new petrographic and chemical data from granitic rocks in the central Sierra Nevada with published results of laboratory experiments on igneous melts, indicates that the granitic rocks of the batholith differentiated and were emplaced at pressures of about 5,000 bars—pres- sures equivalent to a depth of burial of about 15 kilo- meters. This is in accord with data inferred from min- eral assemblages in metamorphic rocks in the same area. Local cataclastic structures found by Bateman, Moore, and Ronald Kistler in the granitic intrusives of the western Sierra Nevada, and in certain older plutons in the eastern Sierra Nevada, suggest that these in- trusives have been involved in the later stages of re- gional deformation. The cataclastic structures dip steeply and are parallel to lineations in the metamorphic rocks, such as minor folds axes, elongate pebbles and minerals, and cleavage-bedding intersections. Fritiof Fryxell has prepared a report on the geo- morphology and glacial history of the upper San J oa- quin River Basin from an incomplete manuscript, maps, field notes, diaries, and published reports of the late F. E. Matthes (1960). The report shows the distribu- tion of Wisconsin and pre—Wisconsin glaciers and the location of the crests of moraines. The San Joaquin River flows through a narrow gorge of Pleistocene age, cut in the floor of a relatively mature Pliocene valley. The flanking uplands, which record a cycle of Miocene erosion, are surmounted in places by peaks that are clearly monadnocks. Study by W. H. Jackson, F. R. Shawe, and L. C. Pakiser, Jr., (Art. 107) of gravity data in Sierra Valley, near the northern end of the Sierra Nevada, suggests that the valley is bounded on the north and west by steeply—dipping faults and is filled with Cenozoic de- posits at least 2,500 to 3,000 feet thick. Hydrologic studies In a preliminary analysis of recent climate trends W. D. Simons (Art. 8) points out that during the last 15 years the downward trend formerly exhibited by most streamflow records in the Columbia River Basin has been reversed. During the same period, annual pre— cipitation has increased, and annual mean temperature has decreased. Measurements of stream velocity and related size of transported particles made by R. K. Fahnestock (Art. 87) in the White River below Emmons glacier, Mount Rainier, Wash., showed that boulders as much as 1.8 A—40 feet in intermediate diameter were being moved by water with a velocity of about 7 feet per second. This is a lower velocity than the “sixty power law” would require. In studies of the chemical character of precipitation at Menlo Park, Calif, H. C. Whitehead and J. H. Feth (Art. 304) have determined that the winter rains con— tain appreciable amounts of sodium chloride derived from the ocean, whereas the soluble parts of dust and occluded gases that fill the air and accumulate on the ground between rains contain appreciable amounts of calcium sulfate. Thus the streams receive slightly more sodium chloride during the rainy winter months and slightly more calcium sulfate during the dry summer months. According to J. H. Feth (Art. 84), streams originat- ing along the California coast contain almost twice as much dissolved salt in summer as they do in winter as a consequence of the small amount of summer rainfall. Streams originating along the southern coast contain appreciable amounts of sulfate, chloride, calcium, and magnesium derived from the loosely consolidated sedi- mentary rocks. Streams in northern California are relatively low in these substances because the igneous and metamorphic rocks that border the coast are rela- tively insoluble. On the Alameda Plain at the southeast end of San Francisco Bay, salt water from the bay is contaminat- ing a deeper fresh water aquifer through abandoned wells. R. P. Moston and A. I. Johnson (Art. 386) have located points of leakage in the wells by use of geo- physical methods. Gamma radiation, temperature, fluid- resistance, and self-potential logging methods were used. The logs were made under pumping, recharge, and static conditions. Hydrologic studies in the San Joaquin and Sacra- mento Valley are summarized on pages A—71 and A—90. ALASKA During the past year, geologic mapping, geophysical and geochemical surveys, and surface- and ground- water studies were carried out in all the major regional subdivisions of the State. (See fig. 2.) This work has resulted in a number of new scientific and economic findings of regional significance, which are summarized below. Results of work on permafrost are summarized on pages A—61 and A—65 to A—66, and work on highway geology is summarized on page A—88. Northern Alaska Geologic mapping of the Project Chariot test site area on the northwest coast of Alaska by R. H. Camp- bell (Art. 354) demonstrates that the structure of the GEOLOGICAL SURVEY RESEARCH 1961—SY'NOPSIS OF RESULTS southern Lisburne Hills is dominated by gently folded imbricate thrust plates. The thrust plates, which are composed of the Lisburne group of Mississippian age, have moved eastward over Lisburne and younger strata. The thrusting is interpreted as a near-surface phenomenon caused by gravity gliding down the re- gional dip. G. W. Moore (Art. 220) has concluded from a study of Ogotoruk beach sediments in the Project Chariot test site area that the principal sorting occurs during the transition from calm to storm profiles, when a large percentage of the beach sediment is processed, rather than during periods when the beach profile is in equilibrium. Work in progress on the distribution of post—glacial beach deposits at Cape Krusenstern indicates that the deposits preserve a faithful record of the average angle of wave attack and hence of past wind direction. A cyclic alternation with a period of approximately 1,000 years has occurred between predominant southeast winds of the past and predominant northwest winds of the present. A gravity profile by D. F. Barnes and R. V. Allen along the coastline between Point Hope and Kotzebue shows a 30-milligal low in the Cape Seppings-Kivalina area. This low is apparently produced by the thick prism of Mesozoic sediments that lies between the Tigara uplift and the Brooks Range geanticline. Al- though no profiles were made normal to the coastline, inland and coastline profiles overlap in places and clearly show a positive gradient of about 1 milligal per mile toward the Chukchi Sea. The so—called “Okpilak” granite in the Mt. Michelson area of the eastern Brooks Range has been assigned a Paleozoic (Devonian?) age by E. G. Sable on the basis of lead-alpha age determinations of zircon fractions. The emplacement of the granite may have been con- temporaneous with the development of an east and northeast-trending Paleozoic orogenic belt, oblique to the later “Laramide” belt of northern Alaska and north- western Canada. In a taxonomic study of brachiopod collections from the so-called “Arctic Permian” of the DeLong Moun— tains, J. T. Dutro, J r., (Art. 231) has described a dis- tinctive assemblage including Licharewz'a, H owidom'a. Waagenooo'ncha, Stepa’nwiella, and others. The “Arctic Permian” is an equivalent of the Kazanian (Upper Permian) of Russia. Correlation with the Capitan of West Texas is also suggested. West-central Alaska Geologic mapping in the Koyukuk basin area by W. W. Patton, Jr., and A. R. Tagg has provided evi- dence of a major northeast-trending fault. The fault, A—41 ALASKA .3qu MthwQSooow do 3 guawuon gamma." no Rages—on wEBoam 5324 mo 32: NemEH'N "553mm OE mm. mm. mn_ _V_ VI CV— 09 mm. mm_ mm. _ o / o I o g 0 .A o A o _ o _ n _ Lo|_| o _ c ‘ oN‘w any 0J9 9—W— _ _ _ _ _ as f _ ego Q o o o-Qfib e .V 0 0 o % IQNm o .- J 0000&0 $0 2475544 a q an . Q 4 \ \ “V 8259 a :0 w ) on our. Q 9 v , P 9 + . . . _ _ _ _ _ g a z 4 lo¢n . @ out oi. own. om: com. on: em: aw: out 0% a A m , 5:53. \ EVMQQ utkTuq‘u. 0 m024 /, v oom\ I; 32:3. , 0 / mm / 3:22 ‘ozntm a com. { B :61 .mb 555:5 23:21 o omm\ 7v 2% b .v any loan 8 y. 353 D V m A» ._ 32:2,. .5 oow_\ J .ljljllj .v . “2:208 00. o cc. 5322 94/. loom « *6. oo 4% 0 355:2 5 ._ 8:2an .5 ON? a 3:: v 2232 /oNo 252 N .3955 \ . TS \\ 528238 0 3. 2:51 a(\ vox waaom .m 1;: 33.5» \ 0 53835.58 .v ' \ . 2' A 0:323. lavw Etcwolgom M . * no ~ _C._._Cmol.—mm>> .N s «a; \x u .\ Emztoz _ ml 4‘ Eufi Em C0 moz221: \ 08" N5 M"; “TN < P‘\ N S ~17oo 0‘4 ‘ko ROSS Modified from U. 8. Navy i Hydrographic Office Chart H. O. 6634, lst Edition, ICE August, 1956 I -180° 90° SH ELF ROSS I t Erebus ISLAND up \0 - . a a A’ Mcdeo - 4 o - ,170 Sow”; \ — (LO 7‘ Tay'°' Va“ey ‘44 \>~ ANTARCTICA \ #4 Davis Valley P‘ a ’V s 00 . 0 I o o 00 us Q0 Q o :' 160 /\f3 )‘X {b 910 FIGURE 4.—Index map of part of Antarctica showing areas of geologic mapping, geologic studies, and geologic reconnaissance by the Geological Survey, 1957 through 1961. A—52 a very common constituent, suggesting affinities with Precambrian( ?) charnockitie rocks of East Antarctica. These rocks are assigned to the basement series of the trans-Antarctic mountains. The mesalike form of the main massif and the presence of a northeastward-trend— ing ice escarpment suggest that normal faults are major structural elements of the mountains. Geology of central Marie Byrd Land Study of aerial photographs by E. L. Boudette and W. H. Chapman has shown that “Mount X Ray” (provisional) identified during “Operation High Jump,” is in reality Mount Murphy (fig. 4), which previously was mislocated. The approximate true posi- tion of Mount Murphy is near the seacoast at lat 75°30’ S., long 109°30’ W. This is 40 to 50 miles southwest of the position shown on published maps. The new position of Mount Murphy requires a corresponding southwestward adjustment in the position of the coast- line. Boudette has recently described an unusual rhomb- porphyry, anorthoclase trachyte from the Crary Moun- tains, a group of stratovolcanoes (approximately lat 76°45’ S., long 117°30’ W.). The trachyte is similar to the “kenyte” of the Ross Island area and also to a rock from the Executive Committee Range. Thus, the Crary Mountains are part of a'soda-alkaline volcanic province that extends from the western Ross Sea region through Marie Byrd Land. The presence of glass in the Crary Mountains trachyte suggests that the volcanic rocks of this province are probably no older than Cretaceous. Boudette found medium- to coarse-grained diorite resting unconformably beneath mafic volcanic rocks in the north end of the Executive Committee Range at approximate lat 76°00’ 8.; long 124°00’ W. (fig. 4). Although water-laid sediments are interstratified with the volcanic rocks of Marie Byrd Land, this is not proof that the volcanics predate the ice cap, for Boudette has found that melt water forms in areas where the atmospheric temperature does not usually rise above freezing. Moreover, the stratovolcano cones of Marie Byrd Land may have been offshore islands before their ice covers coalesced with the ice of the main plateau. Geology of the Thurston Peninsula-Eights Coast regions J. C. Craddock of the University of Minnesota, and H. A. Hubbard,15 working in cooperation with the 1960 US. Bellingshausen Sea Expedition, found that bed- rock in the easternmost part of the Thurston Peninsula (fig. 4) is a gneissic to massive, medium-grained diorite 16Craddock, J. C.. and Hubbard, H. A., 1961, Preliminary geologic results of the 1960 US. Expedition to the Bellingshausen-Amundsen Sea, Antarctica: Science, v. 133, no. 3456, p. 886—887. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS that contains schistose layers. This may correlate with the diorite found by Boudette in the Executive Com- mittee Range. Planar structures in diorite on two off- shore islets near the central part of the peninsula and on a nunatak near its western end strike northeast and dip 30° SE. Sandstone pebbles identified by Hubbard from dredgings oil the coast of the Thurston Peninsula are not likely to have come from this crystalline rock terrane, and perhaps were carried long distances by ice rafting. Coal in the Antarctic Coal of probable Permian age is reported from eight widely separated localities along the trans-Antarctic mountains (fig. 4). The coal is approximately of semianthracite rank. According to J. M. Schopf (Schopf and Long, 1960), it reached this rank as a result of lithostatic loading beneath a great thickness of sediments deposited in a geosynclinal belt during late Paleozoic and early Mesozoic time. Although diabase sills, as much as 2,000 feet thick, are common in the coal—bearing sedimentary rocks of Victoria Land, the thermally metamorphosed coal does not show cok- ing or shrinkage efl'ects. Consequently, Schopf be- lieves that the coal had essentially reached its present rank before the diabase intrusion. High—rank coal is found within 200 miles of the South Pole in the central Horlick Mountains (approx- imately at lat 85°30’ 8.; long 124° W.). Samples of this coal collected by W. E. Long and examined by Schopf contain fossil wood in which the annual growth rings are nearly a centimeter thick. These rings are comparable to those of rapid—growing trees in favor— able sites in temperate climates. Schopf therefore eon— cludes that the Permian climate of Antarctica was at least as warm as temperate. Geology of the Taylor Dry Valley area Warren Hamilton and Phillip T. Hayes, continuing studies related to their field work during the 1958—59 austral summer, attribute layering in a quartz disbase sill to upward migration of interstitial liquids. Lat— eral movement of partly differentiated magma resulted in complications of the layering structure. In the same vicinity as the diabase sill Hamilton and Hayes (Art. 224) find the flowage of the Taylor Glacier (fig. 4) is mainly by shear along discrete planes near its base, and partly by pervasive laminar shear along foliation planes. Granites of the Ross Sea region A chemical comparison of the granites of the Ross Sea region by Warren Hamilton (Art. 225) has shown that the Cambrian( ?) rocks of the oldest Paleozoic orogen, ranging in composition between quartz diorite GEOLOGICAL AND HYDROLOGIC INVESTIGATIONS IN OTHER COUNTRIES and quartz monzonite, are relatively high in rare—earth elements. In contrast to these rocks, the younger Paleozoic( ’2) granodiorites and granites of West Ant- arctica (long 0° through 180° W.) are high in trace contents of chromium, copper, nickel, and tin. The rocks of the Palmer Peninsula of Cretaceous or early Tertiary age are dominantly quartz diorites. Glacial geology of Antarctica Continued studies of surficial deposits in the Me— Murdo Sound area (fig. 4) mapped by Troy L. Péwé (1960 a, b, c) during the 1957—58 austral summer dem- onstrate at least four major Quaternary glaciations. Algae dated by E. H. Olson and W. S. Broecker indi- cate that the age of the last glaciation is at least 6,000 years. A moraine with a core of dead ice, at least 6,000 years old and blanketed by 1 to 10 feet of vegeta— tion-free drift, covers about 85 square miles and is the largest ever reported. The ice cores of similar mo- raines in temperate and subarctic latitudes are known to persist for only a few centuries. Recent work by Péwé has shown that the age of sand-wedge polygons in the McMurdo Sound area is directly proportional to the width of the overlying troughs; some wedges in the area have been determined by this relationship to be at least 1,000 years old. A dehydrated~ seal carcass collected by Péwé about 100 yards in front of the snout of the glacier in Davis Valley (fig. 4) is 200 to 500 years old as dated by Broecker, indicating that the glacier has not advanced beyond the position of the seal during this period. GEOLOGIC AND HYDROLOGIC INVESTIGATIONS IN OTHER COUNTRIES Under the auspices of the International Cooperation Administration, the Geological Survey is currently working with many other governments in geologic and water-resources investigations broadly directed toward advancement of national economies. A major objective of the program is to assist these/y governments in establishing or expanding locally staffed and man- aged organizations that will carry forward inde- pendent programs of work on mineral and water resources. In most countries this assistance includes consultation and advice, demonstration, and direct project activities. (See page A—139 for a list of current projects.) The following statements highlight. new in- formation acquired during the course of this work. Other new information acquired as a result of work in other countries is summarized on pages A-6, A—7, and A—83. Thorium and rare-earth deposit, Brazil A large deposit of thorium and rare earth at Morro do Ferro, which was discovered in 1953 as a result of 608400 0—61—5 A—53 airborne radioactivity studies by the US. Geological Survey, has been mapped and sampled by Helmuth Wedow as part of an exploration program sponsored by the US. Atomic Energy Commission in collabora- tion with the Brazilian National Research Council and the Departamento Nacional da Producao Mineral. The country rock, deeply decomposed, is probably syenite-phonolite. A magnetite stockwork, probably representing a late stage in the cycle of alkaline in- trusion, cuts the country rock. The mineralizing solu- tions containing thorium and rare—earth elements followed the emplacement of magnetite, enriching the highly fractured rocks and the borders of some of the magnetite veins. Assays on unconcentrated material show a range of 0.13 to 3.77 percent equivalent ThOZ and 1.5 to 21.13 percent total rare-earths oxide. The uranium content of these samples is generally in the range of 0.00X to 0.0X percent. Mineralogic study indicates that much of the thorium is present as thorogummite, although some occurs in allanite. The rare earth elements occur chiefly in the allanite and in the rare-earth fluocar- bonate, bastnaesite. Diamond deposits in Bahia, Brazil Diamonds are produced on a small scale by primitive methods in two districts in Bahia—the Chapada Dia- mantina in the central part of the State, and the Lavras Diamantinas farther south. In both districts the dia- monds are concentrated in local stream gravels. Recent geologic mapping in the Chapada Diamantina district by Max G. White and C. T. Pierson has shown that the diamonds are derived from beds of sandstone and conglomerate correlated with the Tombador series of Silurian age or younger, whereas it had been assumed previously that the source rock was the Lavras series of Precambrian or Early Cambrian age as in the Lavras Diamantinas district. » Uranium in the Serra de Jacobina, Bahia, Brazil According to Max G. White, uranium and gold at Morro do Vento, south of J acobina, in the Serra de J acobina, occur in conglomerate and quartzite of Pre- cambrian age. The deposits were formed by hydro- thermal solutions introduced along a fracture or fracture zone. In the Main Reef, the principal deposit, the mineralized rock averages about two meters in thickness through a strike length of 1,260 meters. The zone of mineralized rock extends across quartzite and conglomerate beds, and its distribution is in no way controlled by lithology. Near the surface, the Main Reef contains an average of 0.0076 percent equivalent uranium oxide and 10.0 grams of gold per metric ton. A—54 GEOLOGICAL Geologic studies of iron deposits of Brazil Recent stratigraphic and structural studies of the Precambrian rocks in the iron district of central Minas Gerais by George C. Simmons and Charles H. Maxwell in cooperation with geologists of the Brazilian Depar— tamento Nacional da Producao Mineral, has resulted in establishing the stratigraphic position of a thick sequence of rocks, including a very thick quartzite of great lateral extent, that had never been satisfactorily established by previous work in the area. The con- clusions drawn from the study permit the solution of other general and specific structural problems, par- ticularly in the underground mapping of the iron formations. Chilean earthquakes of May and June 1960 Ernest Dobrovolny and R. W. Lemke studied the earthquake-damaged areas in southern Chile at the re— quest of the Chilean Ministry of Public Works and the Instituto de Investigaciones Geolégicas of Chile. The areas of excessive damage were found by mapping to be on alluvium, landslides, or artificial fill. Surface faulting was not observed although changes in eleva- tion that occurred along the coast may be due to move— ment. along a north-trending fault. Origin of Chile nitrate deposits Geologic field investigations of nitrate—bearing salt deposits of northern Chile by George E. Ericksen in cooperation with the Instituto de Investigaciones Geo— légicas of Chile have shown that geologic, physio- graphic, and climatic conditions of today are similar to those prevailing since the saline deposits started to accumulate, probably in Pleistocene time. The salts were derived by leaching of rocks, chiefly rhyolite tufl's, on the western slope of the high Andes where precipitation is appreciable. The salts are carried by surface and ground water and precipitated in closed basins on broad flats in the high Andes, the coast range, and intervening lower-lying areas. Chemical analyses of rhyolite tufl' samples from two areas show a total soluble salt content of 0.1250 to 0.2705 percent, including the ions Cl, S04, N03, Na, Ca and K—the ones that are most abundant in the saline deposits. Iron deposit in Libya On behalf of the Ministry of National Economy of the United Kingdom of Libya, Gus H. Goudarzi has been engaged in studies of recently discovered sedi- mentary iron deposits in the Shatti Valley of Fezzan province in western Libya. The deposits have been explored by diamond drilling and by detailed geologic mapping of an area of about 3,500 square kilometers. The deposits are contained in beds and lenses at the SURVEY RESEARCH “Mil—SYNOPSIS OF RESULTS base of a sequence of rocks of Early Mississippian age. The rocks are of shallow—water origin. The iron-rich beds are intercalated with shale and siltstone. They are exposed for a distance of about 80 kilometers and average about 5 meters in thickness, with a maximum of about 11 meters. The ore is oolitic to finely granular. The oolites are chiefly hematite and to a lesser extent goethite embedded in a matrix of hematite and hematitic siltstone. Chamosite and siderite are present in small amounts, and limonite occurs as an alteration product. Petroliferous rock is associated with the iron deposit in most areas. Minimum reserves of iron-rich rock indicated by dia- mond drilling are of the order of 700 million metric tons. Representative rock contains: Fe, 48.00; Si02, 16.61; P205, 0.62; S, 0.22; and Al, 3.25 percent. Fluorspar deposits of Mexico A survey of 12 major fluorspar districts in 9 States of Mexico by Ralph E. Van Alstine accompanied by Samuel Estrada and Ernesto de la Garza (Art. 226) indicates that reserves can sustain production for many years at the present rate. More than two-thirds of the deposits examined are in limestone of Early Cretaceous age. The others are in shale or volcanic rocks that overlie the limestone, within or next to intrusive Terti- ary rhyolite, or in andesitic rock and phyllitic shale of probable Paleozoic age. The ore consists predomi- nantly of fluorite, calcite, and quartz or chalcedony and is estimated to average 65 percent Can. In some de— posits the calcite content increases with depth. Small quantities of barite, celestite, gypsum, native sulfur, pyrite, sphalerite, galena, chalcopyrite, iron oxides, or maganese oxides are present in most of the ores. Fluor- spar reserves in the districts visited are estimated to be about 5 million tons of measured and indicated ore and 10 million tons of inferred ore, averaging about 65 percent Can. Phosphorite deposits in Mexico As part of a cooperative project with the Instituto Nacional para la Investigacion de Recursos Minerales of Mexico, Cleaves L. Rogers and Roger Van Vloten have mapped and sampled a large area of marine phosphorite in north-central Mexico. The phosphorites are limited mainly to one member of the La Caja formation of Late Jurassic age and its nearshore equivalent, the La Casita formation. The richer phosphatic beds are composed mainly of apatite, calcite, and chert mixed in widely varying proportions. Most of the phosphate is primary, but some material has been dissolved and redeposited, probably under dia— genetic conditions. Primary phosphate forms small, generally structureless, pellets and nodules ranging in GEOLOGICAL AND HYDROLOGIC INVESTIGATIONS IN OTHER COUNTRIES size from 0.05 millimeter to about 3 centimeters. The phosphate mineral is carbonate—fluorapatite similar to that of the phosphorites in the Phosphoria formation. Reserves total about 77 million metric tons of phosphate rock averaging about 19 percent P205 and about 75 million tons of submarginal phosphate rock averaging about 14 percent P205. Iron deposits in West Pakistan An investigation conducted by Walter Danilchik, a member of the advisory team attached to the Pakistan Geological Survey, in cooperation with geologists of that organization, has revealed that a sedimentary iron formation of Early Cretaceous age in the Surghar and Western Salt Ranges, Mianwali district, West Pakistan, contains about 170 million tons of proved reserves averaging more than 29 percent iron (Art. 371). The formation grades eastward from glauconite to chamo— site and limonite, possibly corresponding to a transi— tion from marine to terrestrial environments during deposition. The iron-rich stratum is in the upper part of the Chichali formation of Neocomian age. It consists of glauconitic sandstone having a maximum thickness of 200 feet. In the high elevations of the Surghar Range, the outcrops of the layer are generally continuous. In the Salt Range, the stratum is discontinuous and poorly exposed. Chemical analyses of a five-part channel sample across a 22-foot bed believed to be repre- sentative of the iron-rich stratum show the following percent averages: Fe203, 45.88; SiOZ, 26.08; A1203, 8.13; 002, 1.9; CaO, 0.68; Nazo, 0.10; P205, 0.52; K20, 2.97; loss on ignition, 12.70. Mineral resources of Taiwan According to Sam Rosenblum, who is acting as ad- visor to the Geological Survey of Taiwan (Formosa), the mineral resource position of the island may be sum- marized as follows: Reserves of bituminous coal, much of which is of coking quality,.total about 200 million metric tons. Reserves of marble, dolomite and clay are large, but high-grade ceramic clay is scarce. Reserves of native sulfur totaling 3 million metric tons and reserves of pyrite totaling 800,000 tons have been located in the volcanic region of north Taiwan. Volcanic material suitable for use as concrete aggregate is abundant in this part of the island. Metalliferous deposits are few. Copper and gold in the Chin-Kua—Shih mine in northeastern Taiwan are in veins and stockworks in and adjacent to a dacite stock. Several small vein deposits of pyrite, chalcopyrite, and pyrrhotite are found in the metamorphic rocks, and one small manganese deposit has been mined. A—55 New deposits of fluorite and manganese in Thailand Louis S. Gardner and Roscoe M. Smith, who are act— ing as advisors to the Royal Department of Mines of Thailand, report that fluorite has been discovered in commercial quantities in Chiengmai and Ratburi, two widely separated provinces along the orogenic belt that extends from the Himalaya mountains southward through the Malay peninsula. The deposits are veins as much as 4 meters wide and 300 meters long in granite. The ore shoots are as much as 50 meters long. Smaller occurrences elsewhere along the same belt suggest that other deposits of commercial size and grade may be present. The discovery and continued successful exploration of battery-grade manganese in Loei province has stimulated prospecting throughout northern Thai- land. A new manganese district has been discovered in Lamphun province, and several deposits are in vari- ous stages of development and exploration. The new deposits are iron- and manganese-enriched laterites 0n remnants of a terracelike plateau on the periphery of. the Chiengmai and Li valleys. Surface-water resources of the Helmand River, Afghanistan An investigation of the surface-water resources of the Helmand River watershed in southwestern Afghanistan has been in progress since 1952, with ac- tiVe participation of Survey hydrologists. A basic net— work of 16 stream-gaging stations, 3 meteorological stations, and 2 stations for the collection of suspended sediment, has been established. Stream-flow and other hydrologic data obtained from these stations are com- piled, analyzed, and published periodically to guide (a) the adjustment of the inflow-outflow balance in reservoirs in the watershed to downstream water re— quirements, (b) the division of available water in dis- tributary irrigation canals, and (c) the apportionment of water in the Chakhansur Basin between Afghanistan and Iran. Ground water in the Libyan Desert, western Egypt A detailed investigation of the regional ground-water hydrology of five oasis depressions in the Libyan Desert of western Egypt was begun in 1960 by the General Desert Development Authority with the participation of a Survey hydrogeologist. Work to date indicates that the region is underlain by thick and productive sandstone aquifers containing water under artesian pressure. River basin surveys in Iran River basin surveys in Iran, in progress since late 1953 by US. Geological Survey hydrologists cooperat- ing with the Iranian Hydrographic Service of the A—56 Independent Irrigation Corporation, have led to the establishment of a nation-wide network of about 200 stream-gaging, quality of water, and sediment sampling stations. Most of the stations are maintained and operated on a continuing basis. The hydrologic records from these stations have been published an- nually in English and Farsi since 1954 in Hydrographic Yearbooks that are widely used in Iran’s 7-year Plan and elsewhere for water-resources development and management. EXTRATERRESTRIAL STUDIES Geological research in support of space exploration, begun in 1959 by the Geological Survey, was expanded in 1961 on behalf of the National Aeronautics and Space Administration. Three lines of research were followed in 1961: photogeologic mapping of the Moon, investigation of terrestrial meteorite craters and impact phenomena, and investigation of extraterrestrial materials. PHOTOGEOLOGIG MAPPING OF THE MOON Photogeologic mapping of the Moon has been carried out primarily with photographs obtained from the Lick, Pic du Midi,, Mount Wilson, McDonald, and Yerkes Observatories. A generalized photogeologic map of the entire subterrestrial hemisphere of the Moon, at an approximate scale of 1:3,800,000, was completed for the Oflice of the Chief of Engineers, U.S. Army by R. J. Hackman. Preliminary maps of the stratigraphy and structure have been prepared for the National Aeronautics and Space Administration at a scale of 1: 1,000,000 in the general target area for a number of hard landing lunar capsules to be launched as part of the Ranger project. Lunar stratigraphy and time scale Five major stratigraphic subdivisions of the lunar crust have been recognized by E. M. Shoemaker and R. J. Hackman (1960) during the course of detailed photogeologic mapping. In descending order these subdivisions include: (a) rays and the rim deposits of ray craters (the Copernican System), (b) rim de- posits of certain craters that resemble ray craters but are unaccompanied by rays (the Eratosthenian Sys- tem), (c) material of the maria floors (the Procellarian System), (d) a great sheet of material associated with Mare Imbrium and the rim deposits of certain craters superimposed on this sheet (the Imbrian System), and (e) rim deposits and floor material of craters on which the Imbrian sheet is superimposed (pre-Imbrian ma- terial). A lunar time scale corresponding to these five GEOLOGICAL SURVEY RESE'ARCI'I 1961—SYNOPSIS OF RESULTS stratigraphic subdivisions has been adopted as follows: Present time Copernican Period Eratosthenian Period Procellarian Period Imbrian Period pre-Imbrian time Beginning of lunar history Statistical studies of the distribution of Eratosthen- ian and Copernican craters on the Procellarian System suggest that the uppermost part of the Procellarian System is about the same age Wherever it occurs. Com- parison of the crater frequency distribution With the number and age of terrestrial impact structures and the present observed rate of meteorite infall suggests that the Eratosthenian and Copernican Periods, taken together, represent the greater part of geological time. The Copernican Period appears to represent somewhat less that half of this total interval. If this is so, the Procellarian and earlier periods represent compara- tively short intervals of time, but intervals of consid- erable activity in the development of the lunar surface features. Photometric investigations by W. A. Fischer and T. M. Sousa of the Kepler and Copernicus region of the Moon show that each major stratigraphic unit is characterized by a certain limited range of albedo. The ranges of albedo of different systems overlap, but there is generally a distinct change at the contacts. The thickness of the Procellarian System in the. Letronne region of the Moon has been estimated by C. H. Marshall (Art. 361) by reconstructing the topo- graphic surface buried by the Procellarian on the basis of exposed remnants of pre-Procellarian crater rims. The Procellarian covers 240,000 square kilometers in the Letronne region and averages about 1.1. kilometers in thickness, somewhat less than twice the mean thick- ness of the Deccan traps of India or the Columbia Plateau basalts, which cover comparable areas. Structural features Most of the larger Copernican and Eratosthenian cra- ters exhibit the form and detailed surface features ex- pected for meteorite impact craters. Their raised rims have been interpreted as having been formed by de- posits of ejecta, and the crater floors (by analogy with terrestrial impact craters) should be underlain by deep deposits of breccia. Terraces and scarps on the walls of the larger craters appear to have developed by in- ward slumping of the crater walls; the scarps are inter- preted as the traces of normal faults that bound the in- EXTRA'I‘E RRE STIAL STU DIE S dividual slump blocks. Other large isolated scarps on the lunar surface have the form of normal fault scarps and have been so mapped by R. J. Hackman. Small craters alined in rows or chains (in some places with interspersed small domes) closely resemble in size, form, and alinement the maar type of terrestrial volcano. In places the crater chains pass into deep nar— row trenches, termed “rilles.” Elsewhere, rilles may have only a few associated craters or may be unac- companied by craters. The rilles are probably diverse in origin. Some may be formed over elongate, dike- like diatremes; some may be more closely analogous to the Icelandic gja, great fissures in basaltic lava fields; and others may be long, narrow graben. Topographic forms characteristic of the Procellarian System include ridges and low conical to dome—shaped hills. Individual ridges are typically 15 to 30 kilo— meters long, and they occur both singly and in com— plex en echelon systems as much as several hundred kilometers in length. The ridges are probably the loci of anticlines in the Procellarian, but the causes of the buckling are not known. Many of the ridge systems are parallel with the margins of the maria or with buried highs on the pre-Procellarian topography. Many of the low conical and dome—shaped hills exhibit small craters, and thus resemble small terrestrial shield volcanoes according to Hackman. In addition to these individual features, the Moon’s surface is characterized by a larger system of linear forms that may be controlled by a tectonic fabric or network of faults and fractures. The most conspicuous element of this network, originally referred to by G. K. Gilbert as Imbrian Sculpture, is a system of scarps, ridges, and valleys that radiate from a point in the Mare Imbrium. TERRESTRIAL METEORITE CRATERS AND IMPACT PHENOMENA The characteristics of impact craters and the mechan— ics of cratering and other phenomena of high speed im- pact are of fundamental importance in understanding the surface of the Moon because the lunar surface has been subjected to continuous bombardment by high speed particles and meteoroids. Terrestrial meteorite craters Detailed mapping (Shoemaker, 1960) and petro- graphic investigation (Chao, Shoemaker, and Madsen, 1960) of Meteor Crater, Ariz., have indicated several possible structural and mineralogic criteria for the recognition of craters or structures produced by mete- orite impact. Significant advances were made in 1961 in the application of these criteria. The suggestion that natural coesite (first discovered at Meteor Crater, A—57 Ariz.) is diagnostic of the occurrence of high shock pressures was strengthened by demonstration of its presence in fractured sandstone collected by V. E. Barnes of the University of Texas from a second mete- orite crater, 300 feet in diameter, at Wabar, Arabia (Chao, Fahey, and Littler, 1961). In addition, J. J. Fahey and Janet Littler were successful in identifying coesite in samples of strongly shocked alluvium collected by E. M. Shoemaker from the Teapot Ess nuclear ex— plosion crater, a crater at the Nevada Test Site of nearly the same diameter as the Wabar Crater. Following the initial discovery of coesite, E. M. Shoe- maker visited and collected samples from the Ries Basin in Bavaria, Germany, a crater 17 to 18 miles in diameter for which some German and other geologists have suggested an impact origin. The basin yielded samples of suevite, a breccia that Shoemaker inter- prets as formed by fallout of ejected shocked debris, by analogy with similar breccia at Meteor Crater, Ariz. These samples were found by E. C. T. Chao to contain (a) coesite, (b) lechatelierite (silica glass), an impor- tant phase in rocks in the fallout at Meteor Crater, and (c) a pyroxene closely similar to one that occurs in sintered Meteor Crater materials (Shoemaker and Chao, 1960). Partially sintered fragments of crystal- line rocks in the suevite commonly contain in a single specimen several widely different kinds of glass—as would be expected from fusion of polymineralic rocks by shock. The shape of the Ries crater, occurrence of imbricate thrust sheets on its walls and rim, and the distribution of various types of breccia in and outside of the crater appear to have a straightforward explana- tion in terms of impact mechanics. The Ries is the larg- est terrestrial crater for which substantial evidence of impact origin has now been accumulated. A fourth natural crater from which coesite has been identified by Janet Littler and E. C. T. Chao occurs at Lake Bosumtwi in Ghana. This crater, which is 5 miles in diameter, is the second largest crater in the world for which fairly definite evidence of impact origin has now been obtained. At Sierra Madera, Tex., Eggleton and Shoemaker (Art. 342) have found a lens of breccia, 11/2 miles across and possibly as much as 2,800 feet deep, nested in a collar of steeply upturned and overturned beds. By analogy with Meteor Crater, Ariz., the breccia at Sierra Madera is believed to have once underlain an impact crater about 2 miles in diameter. Impact phenomena High speed impact of projectiles fired at the Ames Research Center into different types of rocks has pro- duced craters with various structural features. Inward sloping walls formed by spalling and a central zone of A—58 crushed rock are common to all the experimental craters. Small shatter cones were produced in a block of dolo- mite from the Kaibab limestone (Permian) by impact of an aluminum sphere traveling at 18,400 feet per second (Shoemaker, Gault, and Lugn, Art. 417). The lower limiting shock pressures under which the cones are formed are of the order of 1 to 4 kilobars. H. J. Moore has found that the penetration of the high speed projectiles increases roughly in proportion to the m0- mentum, whereas the volume of the crater is a discon— tinuous function of the energy. The craters grow radially by the separation of discrete concentric spalls. A 0.4 gm steel sphere fired at 4.3 kilometers (14,000 feet) per second into a block of Coconino sandstone (Permian) was both fragmented and partly fused, con- trary to expectations from hydrodynamic theory. D. E. Gault,16 H. J. Moore, and E. M. Shoemaker have shown that the fusion can be accounted for partly by conduction of heat. from the shocked sandstone into the steel and partly by frictional heat produced along shear planes during breakup of the projectile. Low-speed impact of an armor piercing bullet was found by Roach, Johnson, McGrath, and Spence (Art. 272) to produce marked changes of thermoluminescence in a block of marble. The changes in thermolumines- cence vary smoothly with distance from the path of penetration of the bullet. Systematic. variations in thermoluminescence have also been found by Roach in the rocks from several formations in the walls and ejected debris at Meteor Crater, Ariz. The variations in the thermoluminescence of the Kaibab rocks at Meteor Crater are similar to those produced at the Ames Research Center by high—speed impact of pro— jectiles fired into a block of dolomite from the Kaibab. EXTRATERRES’I‘RIA‘L MATERIALS Much of our knowledge of other bodies in the solar system is derived from pieces of these bodies that arrive on the Earth in the form of tektites and meteorites. Tektites ‘ The discovery by E. C. T. Chao of nickel—iron spherules in some tektites from the Philippine Islands strongly suggests that the tektites are related to the impact of meteorites. This evidence, together with cal- culations by D. R. Chapman of the Ames Research Center on the entry velocity of Australian tektites into the Earth’s atmosphere, indicates that these siliceous glassy objects are probably products of large meteorite impacts on the Moon. 1° Ames Research Center, National Aeronautics and Space Adminis- tration. ' GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS In a study of the geologic age and stratigraphic oc- currence of the tektites of Texas (bediasites), E. C. T. Chao and Bettie Smysor have determined that nearly all have come from red, chrty gravel that lies on the Jackson group of Eocene age. The gravel may be de- rived from the Jackson group or it may be a lag ac- cumulation from the younger Catahoula formation. The latter interpretation is in better agreement with a reported K40/A“0 age determination of 29 million years for the tektites. The bulk specific gravity of bediasites determined by Chao, Smysor, and J. L. Littler shows a weak positive correlation and definitely non-random relation with the mass of the specimens. This relation is probably con— trolled by composition, as indicated by the strong cor- relations between specific gravity and refractive index and between refractive index and silica content. The presence of possible crystalline phases is suggested by weak reflections recorded on X-ray films. Partially monitored high—precision analyses have been made by Frank Cuttitta and M. K. Carron for the major constituent elements of the bediasites. Among different specimens the total alkalies increase with silica, whereas alumina, ferrous iron, and titania de— crease with increase in silica. The variations of the principal constituents are of the type that would result from fractional volatilization of a melt of tektitic composition. The metallic spherules discovered by Chao in the Philippine tektites range in diameter from 20p. to 0.8 mm and are scattered through the interiors of the in- dividual specimens. Electron probe and ‘X—ray fluo- rescence analyses by Isidore Adler and E. J. Dwornik have shown that the composition of the spherules is about 95 percent iron and 2 to 3 percent nickel. Chao has found by X—ray diffraction that the principal phase present in the spherules is kamacite ( 0: iron), but that there is a second phase of undetermined composition, probably an iron phosphide, visible also in polished section. It is highly probable that the spherules are derived from meteoritic nickel-iron, and their size and distribution in the tektites resembles the size and dis- tribution of nickel-iron spherules in glasses of known impact origin. By fusing several types of rocks in a solar furnace Friedman, Thorpe, and Senftle (1960a, b) have shown that melts of tektitic composition might be formed from these rocks only if they were melted at temperatures in excess of 2,500° C or heated at this temperature for periods in excess of 20 minutes. The ferric-ferrous iron ratio of the fused rocks compared to that of tektites suggests that any atmosphere in PALEONTOLOGY which tektites were melted had a partial pressure of oxygen less than that on the surface of the Earth. Changes in the magnetic properties of the rocks pro- duced by fusion indicate that a heating period of 15 to 20 minutes at 2,500° C is sufficient to produce mag- netic properties similar to those of tektites. Meteorites Electron probe analysis of minute schreibersite crys— tals in a Canyon Diablo iron meteorite by Adler and Dwornik (Art. 112) has shown that the nickel content of the individual crystals varies widely and does not appear to be related to the enclosing meteorite phases. The schreibersite crystals were evidently not in equilib- rium at the time they were formed or else the equilib- rium conditions were variable. INVESTIGATIONS OF GEOLOGIC AND HYDROLOGIC PROCESSES AND PRINCIPLES Investigation of geologic and hydrologic processes and principles is prompted by (and contributes to) the programs of resource and regional investigations de— scribed in previous chapters. Whereas the resource and regional investigations are stimulated largely by economic objectives, or by the need to know more about the geology of specific areas, the investigations of processes and principles are intended to provide new methods and tools needed for the continued advance- ment of the geologic and hydrologic sciences. These investigations are topical in nature as described below. PALEONTOLOGY Paleontological studies that have to do mainly with regional problems are described in other sections of this report. Findings that have to do with evolution, ecology, systematic biology, and other subjects of gen- eral interest are reported here. Evolution As a part of a study of fusuline zonation in the Toana Range, Nev., R. C. Douglass has recognized at least three lineages in the subfamily Schwagerininae. In one lineage, the genus Tritim'tes gives rise to Pseudo- schwagem'na through a gradational series; in another, Schwagem'na and Paraschwagem'na. are developed; the third lineage develops Parafusulina. Comparison of inter- and intra-colony variation in rugose corals from the Onondaga limestone in New York by W. A. Oliver, J r., has shown that the positive correlation between diameter and number of septa is not invariable. The data suggest that number of septa may be genetically controlled. Intercolony variation is greatest in stratigraphic units that include the largest number and variety of associated corals. A—59 N. J. Silberling’s restudy of Middle Triassic mollusks from Fossil Hill, Humboldt Range, Nev., from which most of the fauna described in J. P. Smith’s monograph on Middle Triassic fossils was obtained, demonstrates the presence of nearly a dozen successive upper Anisian faunas. Stratigraphically controlled populations show a wide range of morphologic variation in some species of ammonites, and illustrate the evolutionary gradation from one species to another in the section. Paleoecology Stratigraphic study of Ordovician rocks on the Nevada Test. Site by R. J. Ross, Jr., working with F. M. Byers, H. Barnes, and F. G. Poole (Art. 189), has led to the recognition of sizeable bioherms in the upper part of the Pogonip group. These are correla- tive with a larger bioherm recognized earlier in the year by Ross (Art. 97) during similar study in con- junction with mapping by H. R. Cornwall and F. J. Kleinhampl (1960a) in the Bare Mountain quadrangle of southern Nevada. Preliminary analysis suggests that the limestone in the bioherms may run as high as 95 percent CaCOa. E. R. Applin reports that planktonic foraminiferal species in clastic Paleocene strata from the subsurface of western Florida indicate a habitat that had open access to the sea. A marked reduction in the number of planktonic forms and the absence of certain plank- tonic species among the fauna in the Paleocene beds exposed in Alabama is believed to be due to a restricted, shallow-water marine habitat that was unfavorable to the floating forms. Samples from the Citronelle formation and from the underlying Pascagoula clay of Florida, collected by O. T. Marsh, have been analyzed for pollen by E. B. Leopold. Pollen assemblages from the base, middle, and top of a 340-foot measured section of Citronelle formation, represent essentially the modern upland vegetation of west Florida. Of 40 forms identified from pollen and spores, all now grow locally except 3, and these are northern plants (spruce, hemlock, and Dirca), suggesting a cooler-than-present climate. No pollen could be found in the type section of the Citro- nelle in Alabama. The pollen flora of the Pascagoula clay (of late Miocence age, according to evidence from gastropods) represents a coastal swamp vegetation like the modern one except that of the 36 forms identified, 2 are now exclusively Asiatic trees (Pterocarya, Eucom- mic). In the Pascagoula flora no evidence of spruce, hemlock, or Dz'ma, has yet been found. Sediments from a leaf locality at Red Bluff, Ala., described previously by Berry 17 as belonging in the Citronelle formation, 17 Berry, E. W., 1917,, The flora of the Citronelle formation: U.S. Geol. Survey Prof. Paper 98—L, p. 193—208. A—60 contain a pollen flora identical to that of the Pascagoula clay. From the pollen data, two stratigraphic conclu- sions are possible: (a) evidence from pollen supports a Quaternary age for the Citronelle deposits in west Florida, bearing out the suggestions of Fisk 13 and MacNeil 19; (b) the Red Bluff, Ala., leaf locality prob- ably is not part of the Citronelle formation; therefore, leaves from it enumerated by Berry do not pertain to the age of the Citronelle. The second conclusion agrees with Roy’s 2" field interpretation of the Lambert leaf locality which contains essentially the same flora as the Red Bluff locality. More than 60 genera of plants have been identified by R. A. Scott, from the numerous seeds, wood, and pollen found in the Clarno formation (Eocene) of Oregon. The tropical to subtropical environment suggested by this flora is in keeping with earlier conclusions regard— ing the early Tertiary floras of western United States, based on studies of fossil leaves. In contrast to the leaf assemblages whose affinities are thought to be pre- dominantly with tropical regions of the New World, the Clarno flora contains a high proportion of forms related to modern plants from tropical regions of the Old World. Systematic paleontology Studies by W. H. Bradley, of a very fossiliferous oil shale lamina of the Green River formation, have re- vealed a large and varied flora of microscopic algae and fungi. Three and perhaps four of the minute but well-preserved algae are so unlike living forms that they may represent new families. Three new coral faunas of Silurian age from Maine and Quebec, described by E. C. Stumm and W. A. Oliver, J r., are a mixture in approximately equal pro- portions of North American, European (new to North America), and cosmopolitan forms. The Paleozoic species of Bairdz'a and related genera of ostracodes have been critically examined and re- vised by I. G. Sohn (1960b) in a monographic study that includes identification keys and stratigraphic range charts of genera and species. Publication of this study makes available for stratigraphic use this group of fossils. In the last two years F. C. VVhitmore, J r., and C. A. Kaye have collected several hundred fossil specimens from Tertiary deposits at Gay Head, Martha’s Vine- yard, three miles ofl' the Massachusetts coast. These 1‘ Fisk, H. N., 1945, Pleistocene age of the Citronelle [abs]: Geol. Soc. America Bull., v. 46, no. 12, pt. 2, p. 1158—11159. 1" MacNeil, F. S., 1950, Pleistocene shore lines in Florida and Geor- gia : U.S. Geo]. Survey Prof. Paper 2214”, p. 95—107. ”Roy, C. J., 1939, Type locality of the Citronelle formation, Cit— ronelle, Alabama: Am. Assoc. Petroleum Geologists Bu11., v. 23, no. 10, p. 1553—1559. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS and earlier collections include mollusks, crustaceans, porpoise, primitive whalebone whale, sperm whale, seal, sharks’ teeth, and rhinoceros from the Miocene greensand, and mollusks and the astragalus of a horse from the Pleistocene sands and conglomerates. ’The Miocene greensand appears to be equivalent to the Kirkwood formation of New Jersey and to the Calvert formation of Maryland. It can probably be placed in the Arikareean and Hemingfordian provincial ages of North America and the Burdigalian of Europe. The best fossil for intercontinental correlation is the crab Lobonotus, which occurs in the Burdigalian, Helve- tian, and Tortonian of the Vienna Basin. An im- portant find from the Miocene greensand was a claw of H omarus, the genus to which the modern American lobster belongs. This genus had not previously been reported from deposits older than the Pleistocene. Morphology W. J. Sando (1961) has made a detailed study of ontogenetic trends in a population of Ankhelasma ty- picum Sando, a coral from the Mississippian Brazer dolomite of Utah. Changes in 6 morphologic char- acters were traced through 11 growth stages distin— guished by the number of major septa. The analysis suggests that curvature of the corallum and flattening of its convex side are due to genetic factors associated with maintaining negatively geotropic growth and stability after toppling from an erect, apically at- tached position. Derivation of hypothetical growth curves suggests a progressive logarithmic decrease in the growth rate during ontogeny. Stratigraphic paleontology Studies by Mackenzie Gordon, J r., of fossiliferous sections in the Confusion Range and Burbank Hills of western Utah that had earlier resulted in recognition of 4 major Upper Mississippian goniatite zones in the Chainman shale, now permit the division of each of 3 of these zones into 2 subzones. The 2 uppermost sub- zones of this sequence have also been recognized in south- eastern California. The uppermost one occurs in the Chainman shale of the Inyo Range and Rest Spring shale of the Panamint Range, and the lower one, at the top of the Perdido formation in the Panamint Range. An extensive collection of external molds of a diver- sified molluscan fauna has been obtained by N. F. Sahl from a section of the Upper Cretaceous Mount Laurel sand about 1.2 miles east-northeast of Arneytown, Mon- mouth County, N.J. Aside from the normally well— preserved oysters and belemnites this formation in the past has usually yielded only indeterminable internal molds of other mollusks. Many of the genera repre- sented in the new collections have not been reported GEOMORPHOLOGY previously in New Jersey. The presence of such species as Anomia perlineata Wade, Venericardia subcz'rcula Wade, Pseudomlam's m'pZeg/ana Harbison, Fusinus macnai'r'yemis Wade and others suggests a close affinity with the Ripley fauna of Coon Creek, Tenn. This upper part of the Mount Laurel sand seems to lie within the upper part of the Ewogym cancellata zone. Study by W. A. Cobban and G. R. Scott of about 1,000 collections of fossils from the Pierre shale of the Front Range and adjoining areas shows that Inooem- mus and some other mollusks are useful in zoining the Pierre shale, although few are as restricted in range as the ammonites. Cobban has revised the sequence of straight ammonites (baculites) from the lower part of the Montana group and has recognized many new zones. C. B. Hunt and A. P. Hunt (Art. 81) have recognized four stratigraphic-archeologic stages that are useful to the geologist studying latest Pleistocene and Recent sediments in the southwestern States. The stages are defined by a succession of atlatl or spear point—basketry and arrow point-pottery associations. GEOMORPHOLOGY The study of present-day land forms and geomor- phologic processes is an integral part of geologic and hydrologic studies because the earth-shaping processes of the present may affect the works and plans of man and because they provide clues to the processes of the past. A representative selection of studies in geo- morphology is summarized below. Others are sum- marized under regional headings, particularly on page A—31. Lateritic saprolite in Puerto Rico In the course of geologic mapping in east central Puerto Rico R. P. Briggs (1960) found that lateritic saprolite was developed on various volcanic rock types on relatively flat surfaces in a terrain that otherwise has great local relief. These relatively flat areas are be- lieved by Briggs to be remnants of Miocene erosion sur- faces now deeply incised; they occur largely in the range of altitude between 550 and 650 meters. Later- itic saprolite was found at altitudes as high as 850 meters at a few places in the western part of the area. Chemical analyses made of a profile that grades downward from lateritic saprolite into fresh volcanic breccia demonstrate that laterization was the result of leaching by meteoric waters and was not caused by a fluctuating water table. Interpretation of desert varnish According to C. B. Hunt (Art. 81) desert varnish is rare on surfaces less than 2,000 years old as dated by archaeological remains and structures. Because desert varnish can form only on surfaces that are frequently A—61 wet, he believes that most of the varnish seen in arid re- gions formed during pluvial periods of the late Pleisto- cene. Surficial geologic processes related to volcanoes D. R. Crandell and D. R. Mullineaux working in the Toutle River Valley north of Mount St. Helens Vol- cano, Wash., have studied and mapped flows of volcanic debris that owed their mobility at the time of formation to steam and water. The flows apparently had anoma- lous temperatures of more than 100° C. One bomb- bearing flow contains abundant wood fragments with at least one stump still rooted in the underlying alluvium. Some wood is charcoal throughout, but the rooted stump and some of the fragments are charred only where in contact with the bombs. The debris flow probably originated on the flank of the snow-covered volcano during an eruption as a hot avalanche. Melting snow that was converted to steam probably added to the mobility of the avalanche, and wood incorporated at this stage was converted to char- coal. Cooling during continued downslope movement may have permitted a direct transition from a hot, essentially dry avalanche to a water-mobilized debris flow, cool except for included bombs that retained enough heat to char the wood with which they came in contact. Microrelief features in arctic regions On Latouche Island near Baldez, Alaska, pools with raised rims occurring in sedge meadows have been de- scribed by H. T. Shacklette (Art. 355). The pools oc- cur on impervious glacial deposits and are believed to form Where small streams are dammed by the growth of sedges. The pools are enlarged by ice push and a ridged, furrowed, and hummocky microrelief is even— tually produced. Large rectangular polygons 25 to 60 feet in diameter were found by W. E. Davies (Art. 366) in bedrock at Br¢n1und Fjord in north Greenland. The polygons are developed in gently dipping dolomitic bedrock on smooth glaciated surfaces with low relief. The poly- gons are bounded by ridges of rubble up to 12 inches high and thrust slabs 4 feet high. They are believed to have formed by frost heaving in a manner similar to polygons in unconsolidated deposits. Geomorphology of permafrost Studies in the Fairbanks area, Alaska, by Troy L. Péwé indicate that'periods of permafrost and loess foMation have alternated with periods of deep erosion; these events can probably be correlated with glacial and interglacial stages. The evidence indicates that the existing perennially frozen ground in the area is no older than Wisconsin. A—62 Morphology of stream channels Sediment characteristics affect the morphology of stable alluvial channels through their effect on resist- ance to erosion as well as by their depositional behavior. S. A. Schumm (1960a) found that in alluvial streams containing only small amounts of gravel the Width- depth ratio decreases with an increase in the silt-clay content of bank and bed material. He showed also (1960b) that fine-grained cohesive sediments tend to adhere to channel banks, forming stratification planes concave upward. Nonoohesive sediments tend to be deposited directly on the channel floor, resulting in horizontal stratification in the fill. By studies of the relation of lithology to hydraulic and physical characteristics of stream channels in cen- tral Pennsylvania, L. M. Brush, J r., (1961) found that particle-size changes along a stream show no consistent relation to channel slope. Tributary entrance and parent material were most important determinants of particle size. Downstream change in particle size was found to be much greater in some streams than could be attributed to abrasion or wear. Studies in northeastern Arizona by R. F. Hadley (Art. 156) show that the shape of stream channels is influenced by the growth of saltcedar, which is effective in causing deposition along the banks and on the flood plain. Saltcedar plants grow most abundantly along the high-water line in stream channels, and on flood plains. If 10W flows persist for a few years the seed- lings grow to considerable size. Observations over a 2-year period showed that saltcedar grew about 1.5 to 2 feet per year. During this same period the channel depth increased 0.2 foot; the channel slope increased 0.0005 foot per foot, and channel width decreased 3.1 feet. Hadley believes that deposition induced by growth of saltcedar will result in progressive reduction of channel width until all floods overtop the banks. Mechanics of meandering and irregular channels The magnitude and type of energy losses caused by channel curvature alone were found by L. B. Leopold and others (1960) to depend upon the ratio of channel width to bend curvature below a threshold value of Froude number for the whole channel. At Froude numbers above this threshold, energy losses increase rapidly with velocity. A channel bend having a rela- tively large value of the ratio width: radius, but still within the range of values observed in natural chan- nels, can cause energy losses several times that resulting from boundary friction in a straight channel that is otherwise similar. Leopold and M. G. Wolman (1960) compiled evidence indicating that curves in natural stream chan— nels exhibit a relatively narrow range of the curvature GEOLOGICAL SURVEY RESEARCH l961—SYNOPSIS OF RESULTS ratio width : radius. A large percentage of bends have values lying roughly between 0.5 and 0.3. R. A. Bagnold (1960) demonstrated that this range of values represents a condition of minimum energy loss in curved channels, an observatiOn well known in the study of pipe bends. At the observed value of this ratio there is formed near the convex bank of the curve an eddy that restricts the effective width of channel, and (under a narrow range of conditions) minimizes energy loss. Effective force in geomorphology The relative importance in geomorphic processes of extreme or catastrophic events and more frequent events of smaller magnitude can be measured (a) in terms of the relative amounts of “work” done on the landscape and (b) in terms of the formation of specific features of the landscape. M. G. Wolman and J. P. Miller 21 have shown that the largest portion of the total sediment load in rivers is carried by the relatively frequent events of smaller magnitude. In smaller basins and in drier regions the relative importance of catastrophic events appears to increase. Equilibrium landforms such as sand dunes and beaches may similarly be related to both magnitude and frequency of stress. Geomorphology related to ground water Because the natural movement of water into and out of the ground depends on the forms of the land, many problems concerning water supply, radioactive-waste disposal, and engineering geology may be solved through study of geomorphology. H. E. LeGrand has shown that the general coinci- dence of surface and subsurface drainage patterns in many humid terrains allows a quick appraisal of (a) rates and directions of ground—water movement, (b) maximum limit of recharge, and (0) maximum limits of withdrawal from wells. The influence of local details of geomorphology on ground—water occurrence in alluvial deposits adjacent to mountain fronts in southern Arizona is being studied by Leo Heindl. In this area ground—water yields from wells vary considerably within short distances. Areas of low yield are roughly triangular in shape, with apices away from the mountain front. Because their location and shape are analogous in part to areas of low rainfall, called “rain shadows,” areas of low yield are called locally “ground-water shadows.” These ground-water shadows occur (a) between alluvial deposits laid down by two large washes cutting through the Gunnison Hills in the Wilcox basin, and (b) in the floodplain deposits of the Santa Cruz River in the vicinity of a ”Wolman, M. G.. and Miller, J. P., 1960, Magnitude and frequency of forces in geomorphic processes: Jour. Geology, v. 68, no. 1, p. 54—74. PLANT ECOLOGY gap in the De Bac Hills, south of Tucson. Here, ap- parently, the shadows represent areas of predominantly fine-grained deposition outside the main courses of the channel as it swings through the gap. Geomorphology and geology in relation to streamflow Gains or losses in discharge usually occur where stream and lake beds intersect regional aquifers. In a study of water resources in the eastern Kentucky coal field, carried on in cooperation with the State of Kentucky, G. A. Kirkpatrick, W. E. Price, E. L. Skin- ner, and others have found that, in general, streams draining the relatively impermeable rocks of the Breathitt formation have lower base flows per unit area than those cutting into the more permeable sandstones of the underlying Lee formation. In a study near San Antonio, Tex., carried on in cooperation with the State of Texas, S. Garza reports that significant amounts of stream water disappear underground at points where the streams cross the outcrop of the Edwards and asso- ciated limestones in the Balcones fault zone. This wa- ter is the principal source of recharge to the limestone aquifer supplying the San Antonio area. In a study of Navajo Lake, in southwestern Utah, H. E. Thomas and M. T. Wilson have determined that dis- charge from the lake supplies water to two major drain- age basins—the Sevier River and the Virgin River— by means of subsurface flow'through sinks developed by solution in limestones of probable Eocene age. Con- trolled tests using a discharge-time function and fluorescin dye established the following relations: At intermediate to low stages of Navajo Lake, as much as 40 percent of the discharge may reach Cascade Spring, in the headwaters of the Virgin River, with the re- mainder going to Duck Creek Spring in Sevier River drainage. However, at high stages of Navajo Lake, the sinks through which Cascade Spring is supplied act as a choke and only about 15 percent of the total dis- charge reaches the spring. PLANT ECOLOGY The distribution of plants is influenced in part by geologic and hydrologic environments and the distribu- tion of certain species and assemblages may be indicative of environment. For this reason plant ecology is receiv- ing increased attention by geologists and hydrologists. Relation of vegetation to soil moisture and texture Field studies of grassland vegetation and soil near Palo Alto, Calif., and Golden, Colo., by F. A. Branson and others indicate that the distribution of species and quantity of vegetation are related to soil moisture and texture. A greater variety of species and denser stands, in vegetation composed primarily of exotic annual A—63 plants, grow on sandy soils than grow on nearby clayey soils near Palo Alto (Art. 76). Although soil moisture at saturation and field capacity is much lower in the sandy soils, they believe that the higher infiltration rates and larger quantities of water available to the plants are factors favoring the denser vegetation on sandy soils. In perennial grassland vegetation near Golden, more species grow on stony soil than on shale: derived soil (Art. 239). Species characteristic of prairie vegetation of eastern Nebraska and Iowa are abundant on the stony soil, whereas species character— istic of the mixed-prairie below 6,000 feet in altitude in central and northern Great Plains are predominant on the shale-derived soil. Higher infiltration rates, higher soil—moisture quantities throughout the growing season, and lower soil-moisture tension in the stony soil indi- cate that a greater quantity of available water is re- sponsible for the differences in vegetation. Trees as indicators of floods Evidence of past floods and sedimentation on flood plains has been found by R. S. Sigafoos in the form and wood anatomy of trees knocked over by the floods or partly buried by alluvium. Some trees knocked over by the less frequent large floods are not killed, and vertical sprouts soon grow from the inclined trunks. The age of these sprouts is equal to the number of grow- ing seasons since the tree was knocked over. Trees that are partly buried by deposition of alluvium during floods develop wood in the buried part of the trunk that grows more like root wood than the parent trunk wood. The change is distinct, and elements of the wood can be measured to determine the year of deposition. Along a short reach of the Potomac River flood plain, Sigafoos (Art. 238) has found that trees having a shrubby form are generally flooded 5 times a year, trees about 4 inches in diameter are flooded once in 2 years, and larger trees are flooded less frequently. He con— cluded that the zonation in vegetation on flood plains is determined primarily by the magnitude and fre- quency of floods that are characteristic of a particular valley reach rather than by successional changes of vegetation through time. Trees as indicators of glacial recession In a study of the modern history of alpine glaciers on Mount Rainier, Wash., Sigafoos and Hendricks (1961) found that a moraine from which Nisqually Glacier started to recede about A.D. 1840 represents the maximum advance in at least the last 1,600 years. Moraines downvalley from two other glaciers also represent positions from which they started to recede at about the same time; however, other moraine rem- A—64 nants indicate that recessions from maximum advances occurred also about A.D. 1630 and 17 40. Start of reces— sion was determined by the maximum ages of trees growing on the moraines plus an interval between the start of recession and establishment of the trees. Vegetation as an indicator of man’s activities F. R. Fosberg (1961a) has reported in a symposium on tropical vegetation that man’s activities may have an important long-term influence on tropical vegetation that can be detected long after the abandonment of a human settlement. Indications of such influence in vegetation that otherwise appears normal include: dis- placement of altitudinal belts, dominance by single or few species, presence of exotic species, presence of unusual concentrations of economic plants, and anom- alous habitat relations of communities and species. Large areas of savanna and of open forest, as well as rain forest with unusually well—developed undergrowth, are indications that suggest earlier human influence. This may often be verified by archaeological remains and abnormal soil profiles. Vegetation patterns as indicators of past climates Fosberg (Art. 365) has noted that in certain man- grove areas along the coast of southern Ecuador and central Queensland,- distinctive bare areas exist between the mangrove and the coast itself. This pattern is believed to correlate with seasonally dry climate and resulting high salinity, and a large intertidal range. The influence of vegetation on the shape of stream channels is summarized under the heading, “Morphol- ogy of stream channels,” page A—62. GLACIOLOGY AND GLACIAL GEOLOGY A large part of the United States is covered by deposits formed by glaciers during Pleistocene time. These deposits determine the local topography and soil, and provide local aquifers. The study of glaciers and glacial deposits is, therefore, important to the under- standing of the geology of many areas. A few recent findings of general interest in the fields of glaciology and glacial geology are summarized below. Other findings of local interest are summarized on pages A—ll, A—12, A—13, A~18, A—24, A—36, A—43, A—53, A—63 t0 A—64, A—68, and A—87. Studies of existing glaciers A census of glaciers in the conterminous United States by M. F. Meier has revealed about 1,000 glaciers covering about 198 square miles. Seventy-seven per- cent of the glacier-covered area is in Washington and 9 percent is in Wyoming. An estimated 53,000,000 acre- feet of water stored as glacier ice in the mountains of the West annually contributes nearly 2,000,000 acre- feet of water to streamflow in the summer months. GEOLOGICAL SURVEY RESEARCH “Ml—SYNOPSIS OF RESULTS Analysis of mass budget data from South Cascade glacier, Washington, by Meier (Art. 86) indicated a large deficiency during 1957—58 but approximate bal- ance in 1958—60. Measurements by Arthur Johnson of the changes of thickness of Nisqually glacier, Washing- ton, and Grinnell and Sperry glaciers in Montana indi- cated similar conditions. These studies suggest that, the period of advancing and thickening glaciers in the Pacific Northwest has ended, at least temporarily. According to a recently developed theory, kinematic waves initiated by climatic perturbations travel down a glacier and are the direct cause of advance or recession of the terminus. The first complete set of data on kinematic wave behavior in American glaciers was obtained by Johnson on Nisqually glacier. He showed that a wave traveled down the glacier at an average speed of more than 600 feet per year, several times faster than the speed of the ice. At one location, the ice velocity increased from less than 50 to more than 400 feet per year as the wave passed by. Glacier hydrology By comparing hydrologic' data from basins of South Cascade and Grinnell glaciers with data from similar basins without glaciers, M. F. Meier and W. V. Tang- born (Art. 7) found that glacier runoff is not directly related to precipitation either in timing or amount. Glacier runoff possesses a marked diurnal fluctuation, is difficult to forecast because of the ever-changing> characteristics of the snow and ice cover, and is reg- ulated by natural changes in ice storage. Glacial geology During the course of recent work on the east coast of Greenland, J. H. Hartshorn has discovered evidence of Widespread recent stagnation and retreat of glaciers on Milne Land, and in the valley of the Schuchert River north of Hall Fjord. A study of the history and mode of stagnation and of related glaciofluvial features in this area of modern glacial activity Will aid in inter- preting the history of glacial processes and deposits in places like New England, which have long been free of glaciers. Exploration of Pearyland, North Green- land, by W. E. Davies and D. B. Krinsley supports Lauge Koch’s original observation of the local nature of Pearyland glaciation and of the absence of evi— dence for continental glaciation during Pleistocene time. In the Boston area C. A. Kaye (Art. 34) has found evidence of 5 ice advances and 3 marine transgressions. The oldest glacial drift, recognized in Boston only in borings but exposed on Martha’s Vineyard, is probably of Nebraskan or Kansan age. The successive deposits are of Illinoian, early Wisconsin (Iowan), middle PERMAFROST STUDIES Wisconsin, and late Wisconsin (Cary) age. The young- est drift was deposited 13,000 to 14,000 years ago. The clays deposited during the marine invasions have been overridden by ice one or more times, yet are only mod— erately compacted. (See also p. A—12.) On the east slope of Rocky Mountain National Park, work by G. M. Richmond shows evidence of at least three separate Pleistocene glaciations, which can be correlated with the Buffalo, Bull Lake, and Pinedale gl-aciations of Wyoming. Two minor advances of the ice have occurred since Pinedale time and have left moraines in the cirque heads. The Pliocene to Recent history of the Leadville district and the upper Arkansas Valley of Colorado has been studied by Ogden Tweto. Deposition of Pliocene alluvial—fan materials was fol— lowed by extensive valley cutting, icecap glaciation, additional valley cutting, filling of these valleys by coarse gravels, pedimentation, and finally valley cutting alternating with eight glacial advances. From data on Recent and Pleistocene glaciers in Alaska, T. N. V. Karlstrom has detected evidence of a harmonic or near-harmonic system of paleoclimatic cycles. He suggests that the complex climatic record indicates the superposition of multiples of a 3,400-year glacier substage cycle, and that there is a genetic rela- tion between theoretically derived astronomic oscilla- tions and independently dated paleoclimatic sequences. OCEANOGRAPHY AND MARINE GEOLOGY In the rapidly expanding and potentially fruitful field of oceanography and marine geology, the fiscal year 1961 witnessed increased Geological Survey effort in collaboration with the Navy Hydrographic Office, the Coast and Geodetic Survey and private ocean- ographic institutions. Some of the results of this work are summarized below. Oceanic crustal structure H. S. Ladd, J. I. Tracey, J r., and others have been active in planning and conducting test drilling and in studying materials from the “Mohole project” of the National Academy of Sciences, the ultimate objective of which is to obtain a sequence of samples and measure— ments through crustal rocks and sediments to the Mo- horovicié discontinuity. In preliminary tests off the coast of Lower California a hole 600 feet deep was drilled in water 11,700 feet deep. The well penetrated a sequence about 550 feet thick consisting of sedimen- tary oozes mainly of Miocene age, and bottomed in an augite olivene pillow basalt of undetermined thickness. A—65 Ecologic, zoogeographic, and paleontologic results Analysis by Ruth Todd of Foraminifera from a La- mont deep-sea core off Walfisch Ridge in the eastern South Atlantic reveals an assemblage, mainly plank- tonic, of latest Cretaceous (Maestrichtian) age, com- parable to one from a well along the south shore of Long Island. Study by Patsy J. Smith of benthonic Foraminifera from cores off El Salvador collected by her on a Scripps Institution cruise reveals variation with depth in many species. Some arenaceous species reflect the grain size of the sediment in which they were found, others do not. Among calcareous species showing variation, the deeper water forms tend to be more highly ornate, with wider keels, carinae and costae. - J. C. Hathaway in cooperation with J. A. Ballard of the US. Navy Hydrographic Office found that un- usual engineering properties in some sea bottom samples from the Atlantic Ocean are caused by the occurrence of the skeletal remains of diatoms and coccoliths in the sediments. These highly porous organisms have a high water content per unit weight of the sediments and ap- parently greatly reduce the cohesiveness of the material. The clay minerals in the sediments show only secondary effects on their physical properties. Probable prop- erties can quickly be predicted by electron microscope examination of sediment samples for concentration of skeletal remains. Work by P. E. Cloud, J r., Z. S. Altschuler, and Helen Worthing on samples obtained from Caribbean waters by the Coast and Geodetic Survey has resulted in the clear differentiation of organic oozes formed beneath actively flowing and less active water masses, and the presence of phosphate-enriched limestone at a depth of 150 or more fathoms south from the Bay of Florida. PERMAFROST STUDIES Studies of permafrost continued during the past year in Alaska and Greenland. The work in Alaska was done in cooperation with the Atomic Energy Com- mission, the Office of Naval Research, the Corps of En— gineers, U.S. Army, and the US. Air Force. The work in Greenland was done in cooperation with the Air Force Cambridge Research Laboratories. In addition to the studies summarized below, the geomorphology of permafrost is discussed on page A—61,‘ and frozen ground as it affects highway construction in Alaska on page A—88. Thermal studies Analysis of temperature measurements to a depth of 1,200 feet at the Chariot test site in northwest Alaska A—66 by A. H. Lachenbruch, G. W. Greene and B. V. Mar— shall (in Kachadoorian and others, 1960, 1961) reveals that the present earth temperatures at depth are the product of an ancient period of colder weather and an ancient lower shoreline position. The mean annual surface temperature has increased a total of about 2° C, corresponding to a net annual accumulation of heat by the earth’s surface of about 50 calories/yr/cm2 over the last 6 or 8 decades. If the present climate persists, it will result in a reduction of inland permafrost thick- ness from its present value of about 1,170 feet to about 850 feet. Similar effects have been observed at Point Barrow by Lachenbruch .and Brewer.22 Earth tem- perature anomalies near the shoreline indicate a rapid encroachment of the Chukchi Sea in the last few thou- sand years. This implies that permafrost probably ex- tends beneath the margin of the sea. Preliminary calculations indicate that heat flow from the earth’s interior is slightly over 10‘6 cal/cm'Z/seC‘l. This is close to the worldwide average, and is contrary to the speculations of some that heat flow is anoma- lously large in the Arctic. Areal distribution of permafrost Studies in cooperation' with the Air Force Cam- bridge Research Laboratories were continued in North Greenland at Centrum So by Daniel B. Krinsley (Art. 228). The upper surface of frozen ground in a beach terrace at the west end of the lake was 18 to 21.5 inches below the land surface on May 19, 1960, and by June 30 it had dropped to 22.5 inches. For two days only, July 11 and 12, the frost table dropped to 36 inches and then rose to about 32 inches where it stayed throughout the remainder of July. The frost table was 10 to 15 inches lower near the terrace banks, and ice wedges were visible where the river undercut the terrace. The frost table caused impoundment of numerous small ponds at the west end of the terrace. Polygonal patterns in the sandy gravel of the terrace were mostly 20 to 24 feet on a side. Active polygon ridges were 2 to 4 inches high. Large masses of foliated ground ice in the Galena area on the lower Yukon River in Alaska have been mapped and analyzed by Troy L. Péwé. The ice masses are less than 8,000 years old and have originated in thermal contraction cracks, a process described by Lel‘lingwell.23 Permafrost has been reported by W. G. Pierce (Art. 65) in a peat deposit near Sawtooth Mountain, Wy0., in the southeastern part of the Beartooth Mountains. ”Lachenbruch, A. H., and Brewer, M. C., 1953, Dissipation of the temperature eflect of drilling a well in Arctic Alaska : U.S. Geol. Survey Bull. 1083—0, p. 73—109, figs. 29—35. 23Leiffingwell, E. deK., 1919, The Canning River region, northern Alaska: U.S. Geol. Survey Prof. Paper 109, p. 205—243. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS The presence of thaw depressions, similar in origin to the cave-in lakes or thaw lakes in permafrost terrain elsewhere, suggests that the Wyoming permafrost was formed many years ago. Ground water in permafrost In studiesimade for the United States Air Force, A. J. Feulner has located perennial, or near-perennial, sources of ground water for remote radar stations in Alaska in the shallow alluvium of seasonal mountain streams between the seasonal frost layer and the top of permafrost or bedrock. Periodic observations on cold springs in northwest- ern Alaska by R. M. Waller (in Kachadoorian and others, 1960, 1961) show that: (a) springs occur in this region where permafrost is more than 1,000 feet thick, (b) these springs have a source of recharge, probably from a major river at some distance, (0) the ground water is under hydrostatic pressure causing the spring discharge to fluctuate with diurnal tides and atmos- pheric pressure, and (d) a complicated hydrologic regimen for the potable ground water may be inferred from its variable mineral content. In the Fairbanks, Alaska, area D. J. Cederstrom (1961a) reports that permafrost is discontinuous un- der the Chena and Tanana Valleys. Within the city, permafrost increases in thickness away from the Chena River, and beneath the southern edge of the city it is as much as 225 feet thick. Where permafrost is present, shallow ground water may be available above perma- frost; where shallow ground water is not available or not potable, it is necessary to drill through permafrost to the underlying unfrozen alluvium in order to obtain water. Beneath the gentle hill slopes north of the city water occurs under artesian head in unfrozen ground below a capping of permafrost. The level at which water stands in wells drilled on these slopes is probably determined by the altitude to which the permafrost cover rises uphill. Although drilling through perma- frost is easier than drilling in unfrozen ground, wells passing through permafrost may freeze if not pumped regularly. (See p. A—44.) A test well drilled by the Geological Survey at Kotze- bue on the Chukchi Sea Coast of western Alaska, en- countered water between 79' and 86 feet within an otherwise perennially frozen section. This water has a higher salt content than sea water and may have been concentrated by "a process of fractionation by freezing. GEOPHYSICS Some of the more important findings of the Geologi— cal Survey in the field of geophysics are described be- low under the headings theoretical and experimental geophysics, ad regional geophysics and major crustal GEOPI-IYSICS studies. Geophysicalwork as it relates directly to other fields of geologic and hydrologic research is described under other headings as follows: permafrost, pages A—65 to A—66; thermoluminescence as applied to impact studies, page A~58; construction and engineering prob- lems, page A~88; and the section on regional geology and hydrology, particularly pages A—13, A—16, A—19 to A—20, A—22, A—24, A—25 to A—26, A—30 to A—31, A—36, A—38, and A—43. THEORETICAL AND'EXPERIMENTAL GEOPHY'SICS Paleomagnetism Since publication of their comprehensive review of published paleomagnetic data, A. V. Cox and R. R. Doell 2‘ have made further studies (1961) which indi- cate that the earth’s radius during Permian times was the same as at present, within a measurement error of about 4 percent. They have also concluded that the “last” reversal horizon, found in Iceland, France, Japan, Russia, New Zealand, and Idaho, is almost cer- tainly due to a reversal of the earth’s magnetic field; thus, this reversal horizon (and perhaps a few preceding it) should become a very sharp worldwide marker hori- zon. The reversal occurred sometime during the late Pliocene to early Pleistocene. Magnetic properties of rocks Preliminary studies by Cox and Doell of demagnet- ization processes have shown that rocks may possess an extremely stable component of remanent magnetiza- tion—one that is not altered by magnetic fields of 3,000 oersteds. Cox (1960a) has concluded that certain zones of anom- alous remanent magnetization in basalts are caused by lightning, and that individual cells of highly-mag- netized rock, due to a single lightning discharge, prob-- ably have dimensions on the order of 20 to 100 feet. From a detailed study of one such cell in a basalt in the Snake River Plain of Idaho, he concluded that the cell was caused by the intense magnetic field accompanying a lightning discharge with a peak current of 22,000 amperes. A dual-purpose instrument for the precise determina- tion of remanent magnetization and magnetic suscepti- bility of rock samples is described by L. A. Anderson (Art. 282). Measurements of temperature in uranium ore bodies In analyzing temperature data from a group of drill holes in uranium ore bodies near Grants and Laguna, N. Mex., P. E. Byerly has concluded that anomalies resulting from differences in rock properties are largely obscured by movement of natural and drilling water 2400x, Allan, and Doell, R. R., 1960, Review of paleomagnetism: Geol. Soc. America Bu11., v. 71, p. 645—768. A—67 through the rocks, and that only in rather special cases would radiogenic ore bodies be detectable by tempera- ture measurements in shallow drill holes. Stress waves in solids L. Peselnick and W. F. Outerbridge ( 1961) have in- vestigated the modulus of rigidity, and the internal friction in shear of dry Solenhofen limestone by its response to stress waves ranging in frequency from 4 to 107 cycles per second at room temperature. This is the first time such measurements have been made on a single medium over such a wide frequency range. They found: (a) The modulus of rigidity is constant over the total frequency range for samples of the same density. (b) The internal friction in shear is lower by a factor of 5 in the cycle-per-second frequency range than in the megacycle frequency range. In the infrasonic frequency range, the internal friction in shear increases by 18 percent with the application of a 7.2-kg—per-cm2 static axial tensile stress, but no large change in the internal friction occurs for axial compressive stresses of the same magnitude. (c) The internal friction in shear is strain-dependent, even for strains as small as 10-6 that are induced by a static axial tensile stress superposed on the dynamic torsional stress. In addition to their significance in theoretical geo- physics, these results are important in seismic explora- tion because most laboratory velocity measurements of rocks are made using either the resonance method or the pulse-echo technique, which use frequencies much greater than the frequencies used in seismic explora— tion. The results justify the use of high-frequency elastic data in seismic applications—at least for homo- geneous and well-compacted rocks. L. Peselnick and R. Meister (1961) have investigated a second-order phase transformation in polycrystalline chromium using ultrasonic techniques. The measure— ments were made at frequencies of 5 to 35 megacycles per second in the temperature range —65° C to +60° C. Anomalies in attenuation and velocity for the dila- tational wave were found at. —19° C. The compressi- bility and Poisson’s ratio were calculated, and from these quantities the anomalous specific heat was deter- mined. The value of specific heat thus obtained agrees well with the calorimetric determination by Beaumont and others 25 of the specific heat anomaly, indicating that the anomaly in the specific heat is associated with the structural process. A dispersion in the dilatational velocity was found at —19° C, and on the basis of a single relaxation process the limiting high-frequency velocity and relaxation time were estimated. From 5 Beaumont, R. H., Chihara, H., and Morrison, J. A., 1960, An anom‘ aly in the heat capacity of chromium at 385° C.: Philos. Mag. v. 5, no. 50, p. 188—191. A—68 these calculations a prediction of the magnitude of the attenuation was made, and this agreed within a factor of two with the measured attenuation. By use of a seismic technique, R. E. Warrick (Art. 102) has measured Poisson’s ratio for rock salt and potash ore of the Salado formation in New Mexico. Measurements in the laboratory using an ultrasonic pulse method (Peselnick and Outerbridge, 1961) agreed closely with in-place measurements. Uniaxial compres- sion tests of the ore gave low values at low pressures. but with increase of pressure the values approached those obtained from the in-place measurements. Electrical investigations During recent years equipment has been developed for drill-hole logging of resistivity, guard conductivity, self—potential, induced polarization, and magnetic sus- ceptibility. Field tests of this equipment have been conducted in drill holes penetrating various types of rock and have shown that some rock types and ores can be distinguished more precisely by logging more than one electrical property than by logging a single property. For example, C. J. Zablocki (Art. 241) found that the combination of low resistivity and high magnetic susceptibility in zones of the Duluth gabbro of Minnesota indicated the presence of significant sul- fide mineralization, but that neither characteristic was sufficient by itself. Sometimes the measurement of a single property is adequate, as in the Portage Lake lava series of Michigan, where G. V. Keller (Art. 389) found that the lower resistivity of amygdaloidal upper . parts of flows distinguished them from nonamygdal- oidal parts of the flows. Irwin Roman (1960) has compiled a comprehensive volume of formulas, curves, and tables for the inter- pretation of resistivity surveys on a single overburden earth in which the contacts are horizontal and the two media are both homogeneous and isotropic. Glacial ice of the Athabasca Glacier, Alberta, Canada, was studied by electrical methods by G. V. Keller and F. C. Frischknecht (1960). The resistivity method was useful for determining the thickness and layering of the ice; the electromagnetic method was somewhat superior for determining the thickness of the ice and the nature of the underlying material. F. C. Frischknecht and E. B. Ekren have applied electromagnetic methods to tracing a taconite iron- formation on the Gogebic range. The chief advantage of electromagnetic methods over conventional magnetic methods is that they are not influenced by remanent magnetization. Experimental electromagnetic meas- urements also show promise as a means of estimating the magnetic susceptibility and magnetite content of potential taconite ore bodies. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Induced polarization in rocks Invesigations of induced polarization in rocks have included both laboratory studies of the phenomena causing induced polarization, and measurements of in- duced polarization in rock cores and in drill holes. L. A. Anderson (Art. 416) has determined the depend- ence of the overvoltage of a single pyrite crystal on the amount of current passing through one of its sur- faces and has found significant deviations from the behavior reported for metallic electrodes. G. V. Keller ( 1960) has described experiments to determine the mechanism of induced polarization in rocks not containing the metallic minerals necessary for the creation of overvoltage. His results, which support an earlier paper of Keller and Licastro,26 may be summarized as follows: negatively-charged clay particles at pore constrictions in a rock prevent the flow of anions through the constriction, causing them to pile up near the constriction while they are under the in- fluence of the electrical pulse; when the pulse is inter- rupted, the anions diffuse away from the pileups and create the observed electrical transient. Induced polarization has been measured in drill holes as a part of several field investigations. In Keller’s study of the electrical properties of Precam- brian traps (Art. 389), the induced polarization response was the same for the amygdaloidal and the non—amygdaloidal parts of the traps when determined in the drill holes. Zablocki found a maximum response in gabbro (Art. 241) when it contained a few percent of sulfides; the increase of conductivity attending greater concentrations of sulfides diminished the response. Seismic-electric elfect It has been known for many years that electrical signals accompany seismic waves propagated by earth- quakes and large underground explosions. The elec- trical signals due to some underground nuclear and chemical explosions at the Nevada Test Site 'have been measured by C. J. Zablocki and G. V. Keller (Art. 395). They observed greater voltages along radii from the ex- plosion sites than transverse to the radii. The first voltages appeared at about the same time as the first seismic energy. Electronic computer applications Use of electronic computers in processing and inter- preting geophysical data has increased greatly in recent years. A comprehensive system for analyzing gravity and magnetic fields on digital computers, prepared by R. G. 2«Keller, G. V., and Licastro, P. H., 1959, Dielectric constant and electrical resistivity of natural state cores: U.S. Geol. Survey Bull. 1052—H, p. 257—285. GEOPHYSICS Henderson,27 has been used extensively within and out- side the Survey. Comparative studies by L. L. Nettle- ton and John Cannon show that Henderson’s system is consistently more accurate than others tested for use in determining the errors developed in airborne gravity measurements. Regional effects on contoured geophysical maps are being separated from local effects by a surface-trend analysis computer program, which fits least-squares polynomial surfaces of various order to the observed data. Initiated by G. D. Bath, who did linear surface- trend analyses on a desk calculator, the process has been extended in the computer program to third—order polynomials. Seismic surface wave dispersion methods are an effec- tive means for studying the structure of the earth’s crust. R. G. Henderson and G. V. Keller have initiated computer-oriented studies of Rayleigh and Love wave dispersion in multilayered media. The Haskell-Thom— son matrix formulation of the period equation was used by David Handwerker to write a program that com- putes phase and group velocities of surface waves for given values of wave number or the period for pre- scribed layered velocity and density configurations. Calculations of this kind have been used by S. W. Stewart to test various crustal models. The frequency content of seismograms is being inves- tigated by means of three new aids: (a) a semi-auto- matic device for digitizing seismograms, (b) a computer program that gives the Fourier amplitude and phase spectra, and (c) a new method of machine contouring. Some of these procedures have been used in the com— parison of seismograms from nuclear explosions and aftershocks (Stewart and Diment, Art. 103) and in de— termining the frequency content of initial refraction waves (Diment, Stewart, and Roller, 1961). F. C. Frischknecht and James Marsheck have used the Datatron computer to evaluate the basic integrals given by Wait 28 for the fields of an oscillating dipole over a two-layer ground. The results facilitate use of elec— tromagnetic surveys—particularly airborne surveys— to determine the “background” electromagnetic response of overburden and country rock near ore bodies and to map gently-dipping rock strata. Geophysical abstracts Geophysical Abstracts, a quarterly publication of the Geological Survey, is now in its thirty-third year (Clarke and others, 1960 a, b, c, and 1961 a, b). In 1961, articles abstracted from more than 450 journals in 20 2" Henderson, R. G., 1960, A comprehensive system of automatic com- putation in magnetic and gravity interpretation: Geophysics, v. 25, no. 3, p. 569—585. ”Wait, J. R., 1958, Induction by an oscillating magnetic dipole over a two-layer earth: Appl. Sci. Research, sec. B, v. 7, p. 73—80. 608400 O—Blr—6 A—69 languages increased by more than a third over the num— ber published in 1960. The staff and volunteer abstrac- ters cover literature pertaining to physics of the solid earth, application of physical methods and techniques to geologic problems, and geophysical exploration. REGIONAL GEOPHYSICS AND MAJOR CRUSTAL STUDIES Alaska Gravity data obtained in the Tanana Valley by D. F. Barnes (Art. 383), show a 40 milligal low at Minto Flats, which suggests a thick sequence of rocks of Ter- tiary and Quaternary ages. (See p. A—42.) Pacific Coast L. C. Pakiser (1960) has described a large gravity low in the Lassen Volcanic National Park, Calif., re- gion of the southern Cascade Range. This is an area of predominantly mafic to intermediate rocks, but it also includes a significant amount of silicic rocks. The mass deficiency of the gravity low was found by appli- cation of Gauss’s theorem to be 3X 1018 g, which cor— responds to a volume of 3,700 mi3 of material 0.2 g per cm3 less dense than the enclosing rocks. This mass deficiency is equivalent to a square prismatic load of material of density 2.67 g per cm3, 100 km on a side, and 1 km high. This is approximately the load of the southern Cascades in the Lassen region, so the Cascades are in approximate isostatic equilibrium. The mass deficiency may be caused by a gigantic volcano-tectonic depression filled with low-density volcanic rocks, a mass of low—density crustal rocks such as a silicic batholith, or a combination of the two. As determined by the gravity data, the upper surface of the mass deficiency is no more than 10 km deep. In Washington, west of the Cascade Range, D. J. Stuart (Art. 248) has found that pronounced gravity highs correlate with exposures of Eocene volcanic rocks of mafic composition. The dense crustal rocks of which these gravity highs are the expression must ex- tend to depths of tens of thousands of feet below sea level. Sierra Nevada Isostatic reductions of a closely spaced profile of gravity stations across the southern Sierra Nevada, Calif. by H. W. Oliver, decrease the Bouguer anomaly by 80 to 90 percent, adding considerable support to the theory of isostasy. Calculations using observed gravity gradients and a large number of density measurements of rock samples show that a least part of the isostatic compensation results from a lateral easterly decrease in the density of rocks within the earth’s crust rather than entirely by a mountain root of crustal material protruding down into the earth’s mantle, as envisioned by Airy. A—70 A large gravity low in Long Valley, Calif, has been interpreted by L. C. Pakiser (Art. 106) as the expres- sion of a volcano-tectonic depression. This low is the expression of a mass deficiency of 7.8x10 17 g, which cor- responds to a volume of 470 mi3 of material 0.4 g per cm3 less dense than the surrounding material. A geophysical study of southern Owens Valley, Calif, by M. F. Kane and L. C. Pakiser (1961) indicates - that the deepest parts of the bedrock floor range from 3,000 to 9,000 feet below the surface. Steep gravity gradients outline a series of steeply dipping faults along the boundaries of the valley. A sharp velocity boundary within the valley sediments suggests a change in the rate of deposition, which was probably caused by renewed uplift of the nearby mountain masses. Interpretation of a gravity low at Sierra Valley, Calif, by W. H. Jackson, F. R. Shawe, and L. C. Pakiser (Art. 107) suggests that the valley is bounded by steeply dipping faults, and in its deepest part is filled with a minimum of 2,500 to 3,000 feet of Cenozoic deposits. D. R. Mabey (Art. 249) reports the discovery of a large intrusive body north of Darwin, Calif, based on aeromagnetic evidence. Along the east side of the magnetic anomaly is a gravity high that apparently is produced by dense sedimentary rocks that were altered by the intrusive mass. Basin and Range Regional gravity data in Nevada analyzed by D. R. Mabey, L. C. Pakiser, and M. F. Kane (1960) show an inverse relation to topographic features that are 100 miles or more in width, implying some form of isostatic compensation. Studies by M. F. Kane and J. E. Carl- son (Art. 390) in Clark County, Nev., and by Mabey in Nevada and eastern California indicate that in some places the deficiencies are caused by old masses produced by geologic processes. Mabey believes that some of the larger mountain masses are completely com- pensated. Kane believes that tilting of large crustal blocks may play an important part in the isostatic ad- justment of near-surface mass deficiencies. Electromagnetic measurements made by F. C. Frisch- knecht and E. B. Ekren (Art. 385) over the Helmet fanglomerate of Tertiary age in the Twin Buttes quad- rangle near Tucson, Ariz., show that although individ- ual beds vary considerably in resistivity, the large-scale response is that of an electrically homogeneous medium. Local variations in resistivity and the low over-all resistivity of the Helmet fanglomerate severely limit the investigation of ore bodies at greater depth. Large gravity and magnetic lows associated with the Rio Grande trough indicate to H. J. Joesting and others (Art. 392) that the trough is constricted near GEOLOGICAL SURVEY RESEARCH 196 1—SYNOPSIS OF RESULTS Albuquerque and that the greatest thickness of valley fill and the ancient course of the Rio Grande were west of the present river. Rocky Mountains A gravity low of large area was found in the Yellow- stone Plateau, Wyoming, Idaho, and Montana by L. C. Pakiser and H. L. Baldwin, J r., (Art. 104). The mass deficiency of this low is 5X10 18 g, which corresponds to a volume of 4,000 mi3 of material 0.3 g per cm3 less dense than the surrounding material. The Yellow- stone gravity low may represent a volcano-tectonic depression, a silicic batholith, a magma chamber, or some combination of these. Major structural features in the southern Black Hills, Wyoming and South Dakota, have been delineated as part of a regional gravity survey by R. A. Black and J. C. Roller (Art. 243). Two intersecting steep gravity gradients correlate well with steep monoclinal folding along the western flank of the Black Hills. Gravity data in the southern Rocky Mountains of Colorado indicate to D. J. Stuart and R. R. Wahl (Art. 245) that the mountains are isostatically compensated on a regional scale, but that local masses are not locally compensated. Comparison by Donald Ploufl' (Art. 244) of gravity data obtained in the Harold D. Roberts Tunnel near Dillon, Colo., and on the surface above the tunnel indicates that the density of near-surface crustal rocks ranges from 2.61 to 2.81 g per cm 3. Samples from an area nearby had measured densities in a narrower range. The larger range of apparent densities determined from gravity is considered to be the result in part of anomalously low vertical gravity gradients associated with the mass deficiency that com- pensates the Rocky Mountains. Analysis by G. E. Andreasen and M. F. Kane (Art. 391) of gravity data in the southern Sangre de Cristo Mountains, N. Mex., indicates that the mountain mass is at least partially compensated. Seismic studies A new all-transistorized seismic-refraction recording system for crustal studies has been designed and built by Dresser Electronics, S. I. E. Division, to meet the Geological Survey’s performance specifications. The new system has flat frequency response within 3 db from 1 to 200 cps or higher, a dynamic range of 60 db, high gain, extremely low noise, selective high- and low- cut filtering, and oscillographic and magnetic-tape recording with playback. Six of the new seismic sys- tems have been placed in operation in eastern Colo- rado. A radio-communications system for long-offset seismic-refraction profiles in crustal studies is under development by G. B. Mangan and J. Clark. The sys— GEIOPHYSI'CS tern combines low-frequency (180—kc) transmission from the shot points, multi-frequency transmitters and receivers in a higher frequency range at shot points and recording locations, and a master communications vehicle equipped with 500-watt transmitters at the higher frequencies (3237, 5287.5, and 7880 kc). Pending delivery of the new recording equipment, conventional exploration-type reflection- and refrac- tion-seismic equipment has been used to record high- explosives shots at, the Nevada Test Site and near Rifle, Colo. Recordings of the shots at the Nevada Test Site have been made along a line toward Mono Lake, Calif. Earlier, a seismic-refraction profile from nuclear shots at the Nevada Test Site was recorded between the Ne- vada Test Site and Kingman, Ariz., by W. H. Diment, S. W. Stewart and J. C. Roller (1961). The thick— nesses and velocities of crustal layers obtained on inter- pretation of the traveltime data from this profile were: H0= 1.7 km, V0=5.2 km per sec; H1=26.7 km, V1=6.15 km per sec; H0+ng28 km, V2=7.81 km per sec. R. E. VVarrick has analyzed results of recordings from a 1,000-p0und high-explosives shot in a drill hole in shale at the experimental mine of the US. Bureau of Mines at Anvil Point, near Rifle, Colo. First— arriving energy was recorded at 1.2, 66.5, and 152 km with an apparent velocity of 6.3 km per sec. On the basis of detection of these arrivals superimposed on strong background noise, it was concluded that detecta- ble first. arrivals at 200 km could be obtained from a well-tamped 2,000-pound high-explosives shot in simi- lar rock. Thus, seismic-refraction exploration of the crust using relatively small charges need not be re- stricted to shooting in bodies of water. R. B. Hofmann (Art. 246) has found that energy re- leased by aftershocks of the Hebgen Lake, Mont., earth- quake of 1959 has semidiurnal periodicity. S. W. Stewart and W. H. Diment (Art. 103) have studied changing frequency content as a function of time for earthquake aftershocks and nuclear shots. Such studies, using calculations of Fourier transforms by dig- ital-computer methods, may be useful in determining dispersion of seismic surface waves and identifying events after the first arrivals on a seismogram, such as reflections in the presence of strong background noise. Other studies M. F. Kane (Art. 242) has shown that detailed gravity measurements may be used to determine the approximate size and shape of many outcropping or near surface igneous intrusives and that the application of gravity surveys should be useful in geologic studies of plutons and areas containing igneous outcrops. A-71 Using a similar approach, J. W. Allingham (Art. 387) has computed the relative width of zones of mag- netic rock and the approximate attitude of intrusive contacts in northern Maine by a three-dimensional analysis of aeromagnetic anomalies. Computations for the magnetic fields of prismatic models with infinite thickness and for any magnetic polarization have been started. Analysis of these data by Isidore Zietz (1961) has led to an empirical rule which, when applied to aeromagnetic data, permits the rapid calculation of the in-place direction of the magnetic vector. This simplified procedure will per- mit determination of the in-place direction of the rema- nent magnetization vector in some volcanic areas with- out the time-consuming need for collection and meas- urement of rock samples. Effects of fluid withdrawal Land subsidence caused by the withdrawal of under- ground fluids is occurring in many areas in the United States and in other countries. Studies of the princi- ples controlling the compaction (deformation) of reser- voir systems due to the change in grain-to-grain load caused by fluid withdrawals were begun in the San J oa- quin‘ Valley, Calif, in 1956. These studies have been extended to obtain information on subsidence‘from the same cause in many parts of the world. Notable exam— ples are subsidences of oil fields at Wilmington, Calif, and in the Lake Maracaibo Basin, Venezuela, of gas fields at Niigata, Japan, and in the Po River Valley, Italy, and of artesian aquifer systems in Mexico, Japan, and in Texas and California in the United States. In the subsiding areas in the San Joaquin Valley, Calif, compaction of aquifer systems in unconsolidated sediment-s is being measured directly and continuously by means of subsurface bench marks installed at several depths and by compaction recorders at the land surface. Measured compaction has been shown by B. E. Lofgren (Art. 24) to be directly related to changes in artesian head and to be approximately equal to land subsidence as measured by repeated leveling. As defined by bench marks at several depths the compaction is occurring al— most wholly in the confined aquifer system. Using consolidation tests of core samples from an aquifer system, historic artesian-pressure decline data, and well—log data, R. E. Miller (Art. 26) has shown that compaction computed in accord with Terzaghi’s theory of consolidation agrees closely with subsidence meas- ured at surface bench marks. In laboratory studies of the compaction of fine- grained montmorillonite—rich clayey sediments, R. H. Meade (Art. 116) has developed a numerical index of preferred orientation as a refinement of X-ray diffrac- A—72 tometer methods for study of clay-mineral petrofabrics. During the course of his studies Meade (Art. 324) found that, under compacting pressures up to 60 kg/cm2 (900 psi), montmorillonite does not develop preferred orientation, in contrast to behavior of other clay min— erals of platy habit. S. W. Lohman (Art. 23) has developed an equation for computing the amount of elastic compression of aquifers caused by removal of ground water. J. F. Poland (Art. 25) has applied this equation to studies of compaction and subsidence in the Los Banos-Kettle- man City area, California. He has concluded that for highly compressible and heavily pumped artesian sys— tems, demonstrated to have ratios of subsidence to artesian-head decline of 1/10 to 1/25, the stored water released over a period of years by compaction of fine- grained clayey beds may be 50 times as great as the storage released by elastic expansion of the water and elastic compression of the aquifer system. At the Wilmington oil field, in Long Beach, Calif, compaction of the oil reservoir system had caused 26 feet of subsidence by 1960. Repressuring of the oil zones by injecting saline ground water was begun on a large scale by local agencies in 1958, to control sub- sidence and to increase oil recovery. Subsidence was stopped near some injection wells within 3 months after injection began (Poland, 1960a). Results of the injec— tion program to date suggest that subsidence can be controlled effectively by repressuring. Sensitive liquid-level tiltmeters described by F. S. Riley (Art. 136) are being used to detect the minute subsidence of the land surface that occurs around a pumped artesian well. When correlated with the artesian-head change in the aquifer during pumping, these tests provide data for computing the coefficient of storage and the modulus of elasticity of the aquifer system directly from the aquifer deformation. Results to date indicate differential subsidence on the order of 10 to 100 microns between stations about 5 and 50 meters, respectively, from the pumped well. GEOCHEMISTRY AND MINERALOGY The broad field of geochemistry, mineralogy, and petrology is concerned with the determination of the chemical and physical properties of rocks and minerals, the description of new minerals, experiments and obser- vations on the origin of ores, minerals and rocks, compi- lation of data on the occurrence‘and relative abundance of elements in rocks and ores, and experiments and observations on organic processes and materials. Some of the more important phases of this work are sum- marized below under three main headings: experi- mental geochemistry and mineralogy, field geochemistry GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS and petrology, and organic geochemistry. Findings that are directly applicable to other research programs are summarized under other headings, such as, isotope and nuclear studies, page A—80; geochemical and bo- tanical exploration, page A—95; radioactive waste dis- posal investigations, page A—94; resource investiga- tions, page A—1; and regional investigations, page A—9. EXPERIMENTAL GEOCHEIWISTRY AND MINERAALOGY Mineralogical studies and description of new minerals Several significant studies have been made in minera- logical chemistry. A new procedure for the synthesis of large single crystals of andersonite, NazCaUOz (C-03)3-6H20, developed by Robert Meyrowitz and Daphne Ross (Art. 113), has produced crystals up to 1 mm in average diameter suitable for crystal-structure investigation. E. D. Jackson (Art. 252) has produced an X-ray determinative curve for natural plagioclases of composition A1130 to Anss calibrated against chemi- cally analyzed samples. A critical review of chloritoid analyses by Margaret D. Foster (Art. 259) shows that recent analyses are in good agrement with the structure proposed by Brindley and Harrison. A new heating stage for the X-ray difl’ractometer, developed by B. J. Skinner, David Stewart, and Joseph Morgenstern, has been used for measuring thermal expansions of minerals over a wide range of temper- atures. The thermal expansions of a number of sulfide and selenide compounds have been measured up to their decomposition temperatures. The molar volumes of the aluminosilicates kyanite, andalusite, and sillimanite were measured up to 1,050°C for the first time. For kyanite, which is triclinic, thermodynamic calculations made by S. P. Clark, Jr., B. J. Skinner, and D. E. Appleman (1960) required use of a digital computer to reduce the raw measurements. A. O. Shepard (Art. 264) has shown that zeolites comprising up to 45 percent of tufi's of the Oak Spring formation, Nye County, Nev., are in part mixtures of clinoptilolite and a heulandite-type mineral. These two zeolites, which have virtually identical X—ray powder diffraction patterns at 25° C, can be distinguished by a phase change occurring in heulandite-type minerals at 250° to 350° C. A new tantalum borate, TaBO4, has been found by Mary E. Mrose in a specimen from Manj aka, Madagas— car. The name behierite has been proposed for this mineral, which has a zircon-type structure and is iden- tical with synthetic TaBO4 as described by Zaslavskii and Zvinchuk.29 29Zaslavskii, A. I., and Zvinchuk, R. A., 1953, On the reaction of Ta205 with B203 and the structure of TaBO4: Dokl. Akad. Nauk SSSR. v. 90, no. 5, p. 781—783. GEOCHEMISTRY AND MINERALOGY In a study of merumite, a mixture of chromium oxides from British Guiana, Charles Milton, E. C. T. Chao, Mary E. Mrose, and Blanche Ingram have isolated and identified the phases Cr203, 0102, and CrO(OH). A new sodium calcium vanadyl vanadate, to be named grantsite, has been described by Alice Weeks, Marie Lindberg, and Robert Meyrowitz (Art. 125) from occurrences in New Mexico and Colorado. The new hydrous strontium borate, tunellite, SrO-3B203-4HZO, has been described by R. C. Erd, Vincent Morgan, and Joan R. Clark (Art. 255) from oc- currences in the Kramer borate district and in Death Valley, Calif. Tunellite is isostructural with nobleite, CaO - 3B203 - 4H2. Margaret D. Foster (1960a) has shown from struc- tural formulas that the trioctahedral micas form a com- plete Mg-replacement series, from ideal phlogopite with complete octahedral occupancy by Mg, through the biotites, to siderophyllite and lepidomelane with essen- tially no Mg. A related study (Foster, 1960b) shows that lepidolites can be interpreted as if (a) derived from muscovite by replacement of some of the octahedral Al by Li or (b) derived from siderophyllite, through protolithionite and zinnwaldite, by replace- ment of Fe” by Li. Foster has proposed a new quantitative classification of the chlorites based on: (a) replacement of Mg by Fe”, and (b) replacement of tetrahedral and octahedral A] by Si and Mg, respectively, in the structural formulas. Charles Milton and Mary E. Mrose have found that pathologic lung deposits in the rare disease, pulmonary alveolar microlithiasis, consist essentially of carbonate apatite. Dorothy Carroll (Art. 400) has shown that micaceous laminae in Paleozoic sandstones from Florida consist of elongated flakes of 2M1 muscovite, chlorite and a degraded mica. Crystal chemistry Investigations of crystal chemistry and crystal struc— ture are aimed at a better understanding of structural states and order-disorder phenomena in feldspars. Joan R. Clark and D. E. Appleman (1960a) have com— pleted a study of the crystal structure of reedmergnerite, NaBSigog, the boron analog of albite. The boron-sili- con distribution among the tetrahedral sites was found to be completely ordered. Charge balance calculated on the basis of a simple ionic model was found to give an inadequate picture of the stability of the feldspar structures. D. R. Wones and D. E. Appleman (Art. 260) have re- ported on synthetic monoclinic iron-sanidine, KFeSiaos, formed by the reaction of mica with gas in the sys- tem K20—SiOz—Fe—O—H20. .A—7 3 D. E. Appleman and H. T. Evans, J r., have collabo- rated with N. Morimoto (1960) of the Geophysical Lab- oratory, Carnegie Institution of Washington, in a crystal chemical study of the clinopyroxenes. Deter- mination of the detailed structures of clinoenstatite and pigeonite showed the effect of the introduction of dif- ferent cations into the single-chain diopside-type structure. C. L. Christ and Joan R. Clark haVe continued their structural and crystal—chemical studies of hydrated borate minerals. Refinement of the crystal structure of the synthetic compound CaB305 (OH) has completed the investigation of the colemanite series, 2CaO-3B203~ nHZO. (See Clark and Christ, 1960b.) .Comparison of the bonding and configuration among all members of this series is currently in progress. Joan R. Clark _ and Mary E. Mrose (1960) have described an unusual relationship between the strontium borate minerals veatchite and p—veatchite. The discovery of single crystals of the ammonium borate larderellite, suitable for X-ray studies, has enabled Clark (1960) to com— plete the investigation of the ammonium pentaborate minerals. Crystal chemical considerations have led to the most probable structural formula NH4B503(OH)4 for larderellite. Crystal—chemical studies of uranium minerals have continued with a detailed analysis of the crystal- lographic constants, symmetry, and structural relation- ships of the uranyl oxide hydrate minerals by C. L. Christ and John R. Clark (1960a). Malcom Ross and Howard T. Evans, J r., (1960) haVe solved the crystal structure of cesium biuranyl trisulfate, furnishing the first detailed structural information on a uranyl sulfate compound. The determination of the crystal structure of fair- fieldite, triclinic Ca2(Mn,Fe) (PO4)2-2H20, was com- pleted by Mary E, Mrose and D. E. Appleman (1960) as part of a continuing study of the crystal chemistry of phosphate minerals. The investigation confirmed a structural relationship between the triclinic and mono- clinic members of the A2B(XO4) 2'2HZO series of min— erals, which includes phosphates, arsenates, and sul- fates. Several investigations have been carried out to deter— mine accurate unit-cell dimensions and changes in cell dimensions with changing composition. Shirley Mos- burg, Daphne R. Ross, Philip M. Bethke, and Priestley Toulmin 3d (Art. 273) have refined the cell dimensions of herzenbergite (SnS), teallite (PbSnSZ), and Sn283, as a preliminary step in an investigation of the phase relations in the system Pb—Sn—S. Bethke and Paul B. Barton, J r., (Art. 114) have established the relation- ship between unit-cell edge and composition in PbS— A—74 PbSe and ZnS—ZnSe solid solutions, cadmium-bearing galenas and CuFeS1,90-CuFeSe1,90 solid solutions. Studies on the H—Na exchange in montmorillonite by Alfred Pommer showed that change in interplanar spacing is related to replacement of H+ by Na+ ions in the interlayer positions. Experimental geochemistry Research is continuing on silicate systems of prime geologic importance. David B. Stewart has found that the lowest melting silicate-rich mixtures in the system NaAlSi308—LiAlSiO4—Si02—H20 at 2,000 bars corre— spond in composition to the large, poorly zoned spodu- mene and petalite pegmatites, which are a major world source of lithium. This supports the hypothesis that the pegmatites were formed by fractional crystalliza- tion of lithium—bearing granitic magma. W. C. Phin- ney and Stewart (Art. 413) have studied some physical properties of bikitaite, LiAlSizos-HZO. Reversible dehydration and ion—exchange effects indicate that bikitaite is a zeolite. The dehydration curve shows characteristic breaks at 180° C and 280° C, correspond- ing to loss of 14 and 34 of the water; hydrothermal decomposition to petalite and eucryptite occurs at about 390° C in the range of 1 to 4 kilobars H20 pressure. Results have been correlated with the crystal structure proposed by D. E. Appleman (1960). Herbert R. Shaw has determined points on the four- phase curve (K—feldspar-quartz-liquid—gas) in the sys- tem KAISisOs—SiOz—Hzo at 500, 1,000, 2,000, and 4,000 bars. Liquidus studies have been extended into the quaternary system KAlSigOs—A1203—Si02—HZO at 2,000 bars, and it was found that the liquidus is lowered 20° to 30° C with small additions of A1203. The results imply that about 3 percent muscovite could be produced from the minimum-melting composition in this system at 2,000 bars. Some muscovite granites have approxi- mately this amount, but most muscovite-bearing pegma- tites have considerably more muscovite in bulk composi— tion, as for example, the Hugo pegmatite which has been described by J. J. Norton.30 The addition of MgO to the system KAlSiZOrSiOZ— H20 at 2,000 bars H20 pressure was found by D. R. Wones to lower the minimum melting tempera- ture from 765° C to 710° C, at which temperature phlogopite appears in addition to sanidine, quartz, melt, and gas. The composition at the minimum con- tains about 5 weight percent MgO. At 2,000 bars H20 pressure, the assemblage sanidine—enstatite—gas is unstable and is represented by phlogopite—quartz—gas 30 Norton, J. J., 1960, Hugo pegmatite, Keystone, South Dakota, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400—B, p. B67—B70. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS or phlogopite—melt—gas. The phlogopite—quartz—gas assemblage is stable to above 800° C at this pressure. The optical properties and unit—cell dimensions of biotites on the join annite [KFeSAlSi3010(OH)2]— phlogopite [KMg3AlSi30m(OH)2] and the join an- nite-siderophyllite [KFezAlAIZSiZOm ( OH) 2] have been studied by D. R. Wones (1960) ; complete misci- bility is indicated. Studies of phase equilibria at 1,000 and 2,000 bars gas pressure show that the annite mole- cule reacts with gas to form potassium feldspar, mag- netite (hematite), and a magnesium- or aluminum- rich biotite at temperatures between 400° C and 800° C. Studies by J. J. Hemley (Art. 408) of alteration reactions and hydrolysis equilibria in the system NagO—Algoa—SiOz—HzO at elevated temperatures and pressures have outlined the stability relations among the phases albite, paragonite, montmorillonite, and kaolinite. The relationships are similar to those found by Hemley 31 for K—feldspar, muscovite, and kaolinite except that higher alkali :H+ ratios are needed to crystallize paragonite and albite than are required for the corresponding potassium phases. The experi- mental findings are useful in the genetic interpretation of patterns of wall-rock alteration associated with cer- tain ore deposits. Hemley has also examined the stability relations among analcite, montmorillonite and paragonite and has shown that, at low temperatures and in a silica-deficient environment, the alkali :H+ ratio of the solutions is the principal control on the development of clay as against zeolite. Continued investigation of the system Si02—H20 by George Morey, R. O. Fournier, and Jack Rowe has shown that the solubility of quartz at 25° C is about 6 ppm (parts per million). The rate of equilibration as reported by Fournier (1960) is extremely slow, with extensive metastable solubility (as much as 80 to 400 ppm) occurring for more than 400 days before equili- bration occurs. Investigations of the chemical processes by which various types of sedimentary deposits are formed are in progress on several fronts. In the study of evaporite phase equilibria, E—an Zen has attempted to determine the saturation curves in the system CaSO4—NaCl—HZO by approaching equilibrium from both directions. He has found that anhydrite consistently converts to gypsum, even at 70° C, as much as 30° above the conversion temperature previously reported by Mac— Donald.32 According to the newer data of Zen, the gypsum-anhydrite transition temperature at 1 atmos— phere in the CaSO4 binary is changed from 41° to 46° C. 31Hemley, J. J., 1959, Some mineralogical equilibria in the system Kgo—AIQOTSiOZ—Hzo: Am. Jour. Sci., v. 257, p. 241—270. ”MacDonald, G. J. F., 1953, Anhydrite-gypsum equilibrium rela- tions : Am. Jour. Sci., v. 251, p. 884—898. GE-O‘CHEMISTRY AND Furthermore, calorimetric uncertainties correspond to about i25° for the transition temperature, thus en- compassing all of the conflicting experimental data, including those of van’t Hoff and others.33 Recent work by Robert O. Fournier (Art. 403) shows that evaporite beds in the Salado formation of Permian age in Eddy County, N. Mex., contain wide- spread regular interlayered chlorite—vermiculite. The 28A basal unit expands to 31A upon glycolation and contracts to 24A upon prolonged heating at any tem- perature between 120° and 500°C. Many studies on geochemical aspects of the origin and emplacement of ore bodies are in progress. In attempting to explain some steep thermal gradients that existed during ore formation in the Central City district, Colorado, Paul Barton, Priestley Toulmin 3d, and Paul Sims (Art. 412) have shown that the ore- forming fluid may cool by several processes other than the commonly accepted one of heat exchange with the wallrock, and that the probable major heat dissipating processes at Central City were first the movement of high preSsure, high-temperature magmatic solutions into a low-pressure environment followed closely by the mixing of the solutions with circulating ground waters. Paul Barton and Priestley Toulmin 3d have cali- brated the electrum-tarnish method for measuring the activity of sulfur, as” in laboratory experiments and have determined a number of univariant as, versus temperature curves for geologically important reac— tions, the most important of which is the breakdown of pyrite to pyrrhotite and sulfur vapor. The as, versus temperature curve for this reaction is now known from 743° to 300° C and a large, heretofore un- known, bending of the curve reduces the stability field of pyrite very appreciably at lower temperatures and indicates that stability diagrams calculated for sedi— mentary environments may require extensive revision. The electrum-tarnish procedure has also been employed to define quantitatively the variation of the composi- tion of pyrrhotite (Fe: S ratio) with temperature and, 2152, thus making possible the use of pyrrhotite itself as an instrument for the measuring of asz. As part of a study of the system CoS—FeS—ZnS, W. E. Hall (Art. 115) has determined that the unit- cell edge of ternary sphalerites follows the equation: A=5.4093+0.000456X—0.000700Y, Where A is in angstroms, X is mol percent FeS, and Y is mol per- cent COS. A maximum of about 33 mol percent COS 3avan’t HotE, J. 11., Armstrong, E. F., Hinrlchsen, W., Weigert, F., and Just, G., 1903, ths und anhydrite: Zeltschr. physik. Chemie, v. 45, p. 257. MINERALOGY A—75 can be held in solid solution in iron-free sphalerite at 850° C. B. J. Skinner (1960) has shown that luzonite (CUaAsS4) is the low-temperature polymorph of enar- gite. The inversion temperature is at about 300° C, a factor of some importance in estimating the tempera- tures of formation of certain ore deposits. An asym- metric solvus exists between enargite (CusAsS4) and famatinite (CungS4), and preliminary studies indi- cate that this relation will make the natural assem- blage, enargite plus famatinite, a useful geothermom- eter. Eugene Roseboom (1960) has made an intensive study of the Cu—S system, making extensive use of high—temperature X-ray diffraction techniques. Dige- nite, approximately C119S5 at room temperature, takes increasing amounts of Cu into solid solution with ris- ing temperature until it extends to CugS at about 425° C, where it becomes the cubic polymorph of chalcocite (C1128). The copper-rich digenite solid solutions react so rapidly that equilibrium is reached in a few minutes, even down to room temperature. Thus, natural as- semblages of chalcocite and digenite must, in many cases, represent complete unmixing of a single high- temperature phase. A number of X-ray patterns of natural chalcocites are distinctly different from normal 01128, and they appear to be natural occurrences of a low-temperature synthetic phase the composition of which lies between Cu9S5 and CugS. Composition of water William Back and I. K. Barnes have concluded that values for pH and bicarbonate determined in the lab- oratory are not reliable indicators of whether ground water is in chemical equilibrium With calcite. They have also found (Art. 280) that reliable measurement of Eh in ground water in the field requires complete electrical shielding of the meter and electrode assembly. Special precautions are required to prevent air from entering the water before or during measurements. A potentiometric method of measuring chloride con— tent of ground water has been used by Back (1960a) in field studies. The method uses a sensitive pH meter with a silver—silver chloride electrode and a saturated calomel reference electrode. The dissolved iron content of ground water and field measurement of pH form a basis for estimating Eh in aquifers. Study of the Eh—pH relationships and other factors governing iron content of water by J. D. Hem (1960) suggest that injection of oxidizing water into an aquifer through a recharge well may cause iron to precipitate from the native water as ferric oxide or as hydroxide. Such precipitates can form for some dis— A—76 tance around the injection well and decrease its capacity to take water. Hem (1961a) has also developed a nomograph that simplifies calculation of ionic strength and ion activities from water analyses in parts per million, and a graph (Art. 415) for computing the proportion of dissolved manganese that is complexed with sulfate or bi- carbonate. In studying the changes occurring in solute concen- trations during the progressive wet-grinding of a granitic rock, using surface area increase as a reference criterion, Stanley M. Rogers found that sodium con- centrations increase, whereas silica and potassium con- centrations decrease. Chemical equilibria in aquifers William Back (1961) has applied thermodynamic calculations to the study of chemical equilibria in ground water. By means of field determination of pH and bicarbonate it can be determined whether ground water flowing through limestone areas is saturated with calcium carbonate, in respect to calcite or aragonite. Application by Back (1960b, c) of the concept of “hydrochemical facies” to the chemical composition of ground water emphasizes that the nature and con— centration of ions in solution are determined by the lithology and the ground-water flow pattern of a par— ticular region. Techniques used for mapping hydro— chemical facies are modifications of the procedures used in mapping lithofacies. Geochemical distribution of the elements In a study of the sulfo-carbonate waters and associ— ated deposits in Deep Springs Lake, Calif.——an ephemeral saline lake—Blair Jones (Art. 83) has identi- fied several zones based on the ocCurrence. of saline minerals, including salt complexes, that are due to sequential precipitation of salts from evaporating lake waters. The sequence of mineral zones in the deposits from lakeshore to center is calcite and (or) aragonite, dolomite, gaylussite, thenardite, and burkeite. Minor elements found in the lake brines in significant quanti- ties include arsenic, boron, bromine, copper, iodine, lithium, phosphorus, strontium, and tungsten. R. F. Miller and K. W. Retzlafl' (Art. 22) have cor- related increasing proportions of soluble sodium over calcium and magnesium with the direction of water movement through two deep permeable soils, one a humid residual soil, and the other an arid alluvial soil. Soluble sodium content ranges from 13 to 47 percent in the humid residual soil profile and from 6 to 49 percent in the arid alluvial soil. The observed trends are attributed to ion exchange and to differential salt solubility. GEOLOGICAL SURVEY RESEARCH l961—SYNOPSIS OF RESULTS R. A. Krieger and Gr. E. Hendrickson (1960a, b) report that Greensburg oil field brines from the Laurel dolomite of Silurian age, in the Upper Green River basin, Kentucky, contain from 60,000 to 85,000 ppm of chloride. Brines draining from the oil field have altered the chemical composition of Green River water from an historically calcium bicarbonate type to one of sodium chloride type. At times the chloride content exceeds 1,000 ppm. 1 Weathering and leaching of spoil banks created by strip mining of coal is a source of acid waters in the Cane Branch basin, McCreary County, Ky. Accord- ing to J. J. Musser, the affected waters of Cane Branch below the mining area have a pH range of 3.0 to 3.5. Solution of iron, aluminum, and manganese is accel- erated. For the period October 1956 to September 1957 the chemical load of Cane Branch (500 tons per square mile per year) consisted of sulfate, 69 percent; calcium and magnesium, 15 percent; iron, aluminum, and maganese together, 9 percent; silica, 3 percent; and other constituents, 4- percent. E. F. McCarren, J. W. Wark, and J. R. George (Art. 317) demonstrate how acid coal mine wastes to Swatara Creek, Schuylkill County, Pa., are diluted by inflow from the upper and lower Little Swatara Creek, above J onestown. This stream contains less than 50 ppm of dissolved solids, mostly calcium bicarbonate, whereas overflow mine waters contain more than 800 ppm and have pH values of 3.0 or less. W. H. Durum, S. G. Heidel, and L. J. Tison (Art. 266) have shown that rivers draining about 8,245,000 square miles and discharging 5,350,000 cubic feet per second of water from all the North American continent yield about 611,000,000 tons of dissolved solids an— nually to the oceans. This is equivalent to about 116 ppm or an annual load of 74 tons per square mile of drainage area. Contrasting values are 82 tons per square mile for the United States, and 57 tons per square mile for Canada. In the same study it was observed spectrographically that the minor elements iron, aluminum, strontium, barium, maganese, boron, titanium, copper, chromium, nickel, and phosphorus occur most frequently in the range 1 to 100 micrograms per liter. Lesser amounts of about 15 other minor elements were reported. FIELD GEOCHEMISTRY AND PETROLOGY Differentiation of igneous rock series Studies by G. W. Walker (Art. 200) of volcanic rocks in south-central Oregon have established that soda rhyo— lites, characterized by quartz, anorthoclase, albite, acmite, riebeckite, and enigmatite, or rhonite, were probably produced by magmatic differentiation, and GEOCHEMISTRY AND MINERALOGY were erupted from several volcanoes of Miocene or Plio- cene age. Prior to this discovery, alkalic volcanic rocks were unknown in this part of Oregon. R. L. Smith, R. A. Bailey, and C. S. Ross (Art. 340) find that the alkalic—calcic volcanic rocks of the J emez Mountains, N. Mex., have followed an eruptive-differ- entiation sequence of basalt—andesite—dacite—rhyoda- cite—quartz latite—rhyolite. In the culminating rhyolitic phase, concentration, then subsequent depletion, of volatiles produced a succession of ash falls, voluminous ash flows, and finally extrusion of viscous gas—poor domes and flows. This sequence has been observed by Yamasaki 3‘ in many Japanese volcanoes, and lends fur— ther evidence to the concept outlined by Kennedy 35 that the volcanic cycles are related to volatiles in the magma column. Origin of carbonatites A study by W. T. Pecora of the Rocky Boy alkalic stock of the Bearpaw Mountains, Mont., reveals a close genetic association of carbonatites with a sericitized nepheline syenite volcanic neck. The carbonatites are composed essentially of orthoclase, biotite, calcite, pyr- rhotite, and pyrite, with minor aegirite, apatite, barite, burbankite, ilmenite, zircon, and uranium-rich pyro- chlore. They fill fractures in the brecciated intensely sericitized central part, or throat, of the neck. Pecora concludes that the carbonatite liquid was essentially a syenite magma enriched in H20, 002, and S, and that. sericitization by hydrothermal reaction with subsilicic alkalic rocks released abundant Si and Na for later quartz-vein deposition and soda metasomatism. Late magmatic processes In a field petrologic study of the Late Triassic Wat- chung basalt of New Jersey, G. T. Faust has distin- guished tectonic joints from cooling joints and has classified the cooling joints into “columnar,” “blocky,” and “curvilinear” types in order of descending position. The blocky joints seem to be related to thickness of the flows. Curvilinear joints occupy the greatest thickness of most flows and usually extend to the basal contact. These distinctions have proved to be useful aids in de- termining stratigraphic positions within flows and in mapping structures in the area and elsewhere. Origin of welded tulfs As part of a definitive study of ash-flow deposits, R. L. Smith (1960a, b) has defined zones of nonwelding, partial welding and dense welding and superimposed zones of granophyric crystallization, devitrification, vapor—phase crystallization, and fumarolic alteration. 34Yamasaki, Masao, 1959, Role of water in volcanic eruption: Vol- canol. Soc. Japan 8111]., v. 3, p. 95—106. asKennedy, G. C., 1956, Some aspects of the role of water in rock melts : Geol. Soc. America Spec. Paper 62. p. 489—504. A—77 Application of these concepts in a detailed stratigraphic study of the Bandelier tufl’, J emez Mountains, N. Mex., has permitted Smith, Ross, and Bailey to separate that formation into two major units, each related to a dif- ferent caldera source area. In a preliminary study of the crystal content and chemical composition of welded tuffs from western United States, R. J. Roberts and D. W. Peterson (Art. 320) show that crystal-poor welded tufi's are mostly rhyolitic, whereas crystal-rich welded tufl's are mostly quartz latitic or dacitic. The differences between the two types suggest eruption at different stages in the magmatic cycle of silicic volcanic rocks. Origin of accretionary lapilli A comparative study of accretionary lapilli in tufl'a— ceous volcanic rocks in western United States has been completed by J. G. Moore and D. L. Peck. Features of these structures suggest that they form on dry land or only in shallow water, that the volcanic vent was above water, and that lapilli can be used as a key to post-dep- ositional changes that have affected the host rock. Origin of zeolitic rocks With the recognition in recent years of the zeolite facies much attention has been focused on the stability relations of zeolite assemblages in slightly metamor-' phosed sediments and pyroclastic rocks. In a study of the relation of carbonate-quartz-clay mineral assem- blages to zeolitic assemblages, E-an Zen has outlined the stability fields of both assemblages, and has found (a) that neither need be metastable, and (b) that their com- positional diiferences are determined by reactions in- volving CO; as well as H20. Origin of glaucophane schists R. G. Coleman and D. E. Lee have demonstrated that the glaucophane-schist facies is separate and distinct from the greenschist facies. In the Cazadero area, California, they found metamorphic aragonite, having a microscopic fabric symmetry compatible with that of the enclosing schists, in association with spessartine-rich garnet. Although spessartine garnet, hitherto recorded in the chlorite zone of the greenschist facies, indicates that the grade of metamorphism is similar to that of the greenschist facies, the presence of aragonite indicates that higher pressures (>4000 bars) are characteristic of the glaucophane schist facies. The fact that the aragonite has not inverted to calcite indicates that al- though the pressure was high, the temperature must have been relatively low. Chemical changes in metasomatism On the basis of modal and chemical analyses of meta- somatized rhyolites in the Humboldt Range, Nev., D. B. A—78 Tatlock (Tatlock, Wallace, and Silberling, 1960), has found field evidence that strikingly substantiates the experimental finding of Hemley36 for the system KzO—Ales—SiOz—HZO. From the periphery to the center of the altered rhyolitic area, he finds mineral assemblages ranging from K-feldspar through K-feld- spar—muscovite, muscovite, muscovite—pyrophyllite— andalusite, to pyrophyllite—andalusite. These min- eralogical changes are paralleled by chemical changes with K20 increasing toward and A1203 increasing away from the center of alteration. Chemical changes in metamorphism A. E. J. Engel and C. G. Engel (Art. 262) find that hornblendes in the amphibolitic rocks of the northwest Adirondacks undergo systematic changes in chemical composition and color with increasing grade of regional metamorphism. They also find that many high tem- perature metamorphic hornblendes are deficient in hydroxyl, and do not contain compensating amounts of halogens. In studying the effects of contact metamorphism on various schistose rocks in Connecticut and North Caro- lina, Fred Barker (Arts. 268, 270) finds that the mineral assemblages are consistent with Gibbs’s phase rule. Origin of saline and calcium sulfate deposits W. H. Bradley is studying the geochemical balances of sodium, calcium, and sulfur in the saline member of the Green River formation, Wyoming, and the amounts of these elements brought into the ancient lake basin. He concludes that no unusually sodium- rich source need be postulated to account for the pro- digious deposits of trona and other sodium salts occur— ring in that formation. C. F. Withington (Art. 410) has proposed that the mottled structures in bedded calcium sulfate deposits originated after deposition but before lithifaction and that they grew in place in bottom sediments by crystal- lization from concentrated interstitial solutions. Origin of clays and other sediments A study by E. W. Tooker of the clay minerals in rocks in the lower part of the Oquirrh formation, Bing- ham, Utah, demonstrates an association between clay minerals and rock types. In the rocks studied illite is ubiquitous but most abundant in limestone; regular mixed-layer chlorite-montmorillonite is most common in dolomitic limestone and calcareous quartzite; chlorite is dominant in dolomitic quartzite; and kaolinite is found only in quartzite. No appreciable separate mont- morillonite phase occurs in any of the rocks. Tooker believes that because specific clay-mineral assemblages 3“ Hemley, J. J., 1959, Some mineralogical equilibria in the system Kzo—AIQOrSIOrflzo: Amer. Jour. SOL, v. 257,. p. 241—270. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS occur regularly with specific rock types in this strati- graphic sequence the assemblages were formed in equi— librium with the major rock constituents in the sedi— mentary environments. (Compare with conclusions of Sigvaldason and White, Art. 331.) A. E. J. Engel and C. G. Engel are reviewing a variety of information relating to the nature of sedi- mentary rocks within the framework of continental North America. Their findings to date indicate that the mass of sedimentary rocks exhibits the following secular changes: (a) decrease in graywacke type clas- tics relative to sandstones and shales, (b) decrease in the ratio of total clastics to total chemical and bio- chemical precipitates, (c) systematic change in both mineralogical and chemical composition of sediments, including a marked decrease in the ratio Na : K in clastic sediments. These changes in the continent with time reflect the change of its structure from. a complex of emergent Precambrian geosynclines like those found at the continental border to a more stable, more granitic mass. Origin of ores and ore solutions Analysis of geological and mineralogical relations of hydrothermal thorium deposits in the Wet Mountains, 0010., by George Phair and F. G. Fisher (Art. 293) suggests that such deposits are the by-product of inten— sive potassic feldspathization of granite. They postu- late that thorium, having limited solubility in alkalic solutions, is predisposed to form residual concentrations during feldspathization and, not being accommodated by the growing feldspar, is expelled into the adjacent porous matrix to form enriched protore. P. M. Bethke, P. B. Barton, J r., and M. W. Bodine (1960) have studied the time-space relations of ores at Creede, Colo., through extensive use of thick (0.1 to 10 mm) sections of sphalerite. They have been able to establish a. detailed “stratigraphy” of the successive growth zones of sphalerite that can be traced for several thousand feet through the ore body. Edwin Roedder (1960b) has studied the fluid inclusion compositions and geothermometry of these ores and has shown that thermal and chemical environments differed from one sphalerite generation to the next. In a study of the Sulfur Bank, Calif, quicksilver ore deposit, which was clearly formed by hot-spring activity, D. E. White finds that the distribution of ore and gangue minerals is strongly influenced by the water table. Quicksilver was transported almost en- tirely in water and still is being deposited from nearly neutral water low in sulfide. The present water is chem— ically and isotopically similar to connate and meta- morphic water and is unlike water most clearly related to volcanism. GEOCHEMISTRY AND MINE RALOGY The presence of mercury in brines and crude oil from the Cymric field, Kern County, Calif, reported by E. H. Bailey, P. D. Snavely, J r., and D. E. White (Art. 398), may also have bearing on the origin of quick- silver deposits, as many quicksilver deposits contain significant quantities of hydrocarbons. Hydrothermal rock alteration G. E. Sigvaldason and D. E. White (Art. 331) are studying hydrothermal rock alteration as revealed in drill holes at Steamboat Springs, Nev. They find that the mineral assemblages developed are related to com- position of water, temperature, and depth and, unlike those at Bingham, Utah (see p. A—78), are virtually independent of the original rock types. The principal hydrothermal minerals encountered are montmoril— lonite, kaolinite, illite, several chlorites and mixed—layer clays, potassium feldspar, quartz, calcite, pyrite, and pyrrhotite. Distribution of minor elements As part. of a continuing investigation of the distribu- tion of minor elements in igneous rocks, David Gott- fried, Lillie Jenkins, and F. S. Grimaldi (Art. 108) have determined the niobium content of rocks of three contrasting comagmatic suites: the California bath- olith, the Shonkin Sag laccolith, and the White Moun— tain (New Hampshire) plutonic-volcanic series. In each of these series niobium increases in the more silicic differentiates. In a related study of the White Moun- tain plutonic-volcanic series, A. P. Butler (Art. 31), finds that thorium also increases in the more silicic differentiates. In a detailed investigation of tlie geochemistry of the Pierre shale, H. A. Tourtelot, L. G. Schultz, and Claud Huffman, Jr. (Art. 253), find that the boron content in bentonites and shales seems to be more closely related to the total amount of clay minerals than to particular clay mineral species. In a study of the chemical properties of the minor elements found in coals and carbonaceous sediments, Peter Zubovic, Taisia Stadnichenko, and N. B. Shefi'ey (Art. 411) have characterized the behavior of minor elements in coal-forming environments. They find that partition of elements between organic and inorganic phases and the formation of mineral deposits in such sediments are directly related to ion size and charge, bond configuration, and coordination number. ORGANIC GEOCEEMISTRY Investigations in organic geochemistry have applica- tion in several fields of geology and hydrology. The work summarized below relates primarily to the com- position and structure of certain naturally occurring organic substances. The use of concentrator plants in .A—79 studies of the incidence of disease is discussed on page A—94, and the use of plants in geochemical and botanical prospecting is discussed on pages A—94, A—95 to A—96. Origin of kerogen As one result of comprehensive studies now being made of organic matter in sediments and rocks, I. A. Breger has found that the insoluble organic fraction (kerogen) of certain marine shales consists mainly of humic matter of terrestrial origin rather than organic detritus of marine origin. The fact that such humic matter is not converted to petroleum may explain why rock bodies such as the Chattanooga and the Pierre shales are not important sources of oil. Biochemical fuel cell A"‘biochemical fuel cell” has been devised by F. D. Sisler as a result of observations of electron exchange between marine sediments and the overlying sea water. A laboratory model of the cell produces electrical energy directly from the decomposition of organic mat- ter by bacteria. The cell is composed of two sections, an anode and a cathode, each containing an inert elec- trode connected by an ion—diffusion bridge. A mixture of sea water containing organic matter as fuel and bacterial cells (or enzymes) as a catalyst is placed in the anode section. The cathode contains sea water and oxygen. The oxygen and organic matter could be fur- nished inexpensively by live algae which would utilize solar energy. A great variety of organic waste mate- rials could also be used as an energy source. Iron in water and plant materials The average iron content of aquatic plants studied by E. T. Oborn (1960b) was 4.99 mg per g of dry matter. This is more than 10 times the iron content of most land plants but is similar to the iron content of primitive land species such as lichen. When aquatic plants die and decay they may add considerable amounts of iron to the water in which they have grown. Microbiotic activity greatly facilitates the solution of iron from soil. As a result, dissolved iron can be added to ground water by recharge passing through the soil zone. Work by Oborn and J. D. Hem (1961) has shown that as much as 10 percent of the total iron content of mixtures of soil and organic matter was brought into solution after two weeks of incubation. Amounts of iron dissolved in the absence of organic matter or bacterial action were smaller by a factor of 100 or more. Leaves of trees growing in areas disturbed by strip mining in Kentucky were found by Oborn (Art. 119) to contain more iron than leaves of trees in nearby un- A—80 disturbed areas. Where strip mining has taken place in this area, the iron content of water has increased. ISOTOPE AND NUCLEAR STUDIES Isotope and nuclear studies provide information needed in many different fields of geology and hydro- logy, ranging from studies of the structure and com- position of minerals to determinations of the length of divisions in the geologic time scale. Many such studies are summarized below. Other related studies are sum- marized under other headings as follows: radioactive materials, pages A—6 to A—7; studies related to disposal of radioactive wastes, page A—94; and application of isotope geology to exploration, page A—96. GEOCHRONOLOGY The application of radioactivity dating methods to geologic problems is rapidly expanding. Refinements in methods now permit age determinations to be made on the same mineral or rock by two or more techniques as well as the dating of a number of mineral components from the same rock. Lead-alpha age measurements The lead-alpha method, because of its simplicity, has been applied to many geologic problems. Refinements in the technique for spectrochemical determination of lead in zircons have been reported in a paper by H. J. Rose, J r., and T. W. Stern (1960a, b). The method has been further improved by X-ray fluorescence determi- nation of the Th/U ratios of zircon. The Th/U ratios determined in this way by Harry Rose, J r., and F. J. Flanagan are in good agreement with ratios determined by the isotope-dilution method. Lead-alpha ages of 25 to 30 my (million years) were obtained by M. Griinenfelder and T. W. Stern (1960) on zircon concentrates from the Bergell granite, an intrusive body that cuts the Pennine nappe systems of the southeastern Swiss Alps. Three granitic intrusives in northern and central Chile have been determined to be of pre-Jurassic, Jurassic, and Cretaceous ages, respectively, on the basis of lead-alpha age measurements on 11 zircon concen- trates (Ruiz, Segerstrom, Aguirre, Corvalan, Rose, and Stern, 1960). Lead-alpha age determinations on zircons from a variety of rocks have aided in interpreting the com— plicated geologic history of a part of the Carolina Pied- mont (Overstreet, Bell, Rose, and Stern, Art. 45). Potassium-argon, methods Wherever possible the lead-alpha ages on zircons are now being supplemented by potassium—argon age deter- rubidium-strontium, and uranium-lead GEOLOGICAL SURVEY RESEARCH 196l—SYNOPSIS OF RESULTS minations on micas and by rubidium-strontium age de- terminations on micas, feldspars, and whole rock samples. Rb-Sr age determinations by Carl Hedge on K-feld- spar and whole rock samples of granite and granite gneiss from the Holy Cross quadrangle, Colorado, in- dicate that the time of origin was about 1700 million years ago. Rb—Sr ages on micas from granites and peg- matities in this area agree with the K-Ar ages deter— mined by R. Pearson and H. Thomas and range from 1100 to 1400 my The Laramide orogeny is repre— sented by small plutons dated at 60—70 m.y. Potassium-argon and rubidium-strontium age deter— minations by H. Faul, H. Thomas, P. L. D. Elmore, and W. W. Brannock indicate a complex history of intrusion and metamorphism in Maine. Thermal events occurred in this region during the Devonian (400—350 m.y.) , the Permian (27 0—250 m.y.), and during Jurassic time (180—130 m.y.). Lead-alpha ages, available for many of these samples, commonly are higher, than the K-Ar and Rb-Sr ages and suggest that certain of the dated rocks originated much earlier. Evidence of the Grenville orogeny (approximately 1000 m.y.) in southeastern Vermont is suggested by some of the age determinations. Rubidium-strontium age determinations by R. W. Kistler of Sierra Nevada rocks range from 75 to 100 my. Age determinations by Rb-Sr and K-Ar methods are being used to determine the sequence of intrusions in a regional study by P. Bateman and Kistler. H. Thomas and H. Faul, in collaboration with K. Przewlocki and W. Magda of Krakow, Poland, have dated granite from the Karkonosze and Kudowa plu- tons in southwestern Poland at 300-320 my. Rb-Sr ages of approximately 1400 my were found for mica from cores of the buried crystalline basement in north- eastern Poland. The basement gneisses may be part of the Ukrainian Shield. Graphic and algebraic solutions of the discordant lead—uranium age problem have been presented by L. R. Stiefi' and T. W. Stern (1961). A. P. Pierce (Art. 402) has continued his study of radiation damage and iso- topic disequilibria in uranium-bearing asphaltic nodules. Carbon-14 age determinations Meyer Rubin and S. M. Berthold (1961) have pre- sented a list of radio-carbon dates determined during the past year. These dates have been useful in record- ing changes in sea level associated with changes in cli— mate during the last 40,000 years, and in dating volcanic flows, ash falls, glacial deposits, and fluvial deposits. ISO’I‘OPE‘ AND Protactinium-thorium dating of deep-sea cores Studies of the Pa231/ Th23° dating method by Rosholt, Emiliani, Geiss, Koczy, and Wangersky (1961) provide a reliable means of extending the time scale from the present to about 175,000 years ago. The Pam/Th230 method has been applied to study of two cores from the Caribbean, approximately 600 kilometers apart. The results of the dating of samples from these cores agree with the carbon-14 chronology, but beyond the radio- carbon range the Pam/Th230 measurements indicate that the last interglacial age began about 100,000 years ago and lasted about 35,000 years. LIGHT STABLE ISOTOPES Deuterium in hydrous silicates and volcanic glass The amount of water and its deuterium content in biotite, hornblende, and chlorite are being investigated by Betsy Levin and Irving Friedman with the coopera- tion of John Godfrey of the Research Council of Al- berta. The water is extracted by heating the minerals to 1500° C in a vacuum. Hornblende concentrates from various rocks of the Sierra Nevada batholith show simi- lar water contents, whereas biotite concentrates show considerable variation. A similar relationship is found for hornblende and biotite concentrates from rocks of the southern California batholithic complex. The water and deuterium contents of the biotite from rocks of the complex are related to rock type and SiOz content. In general, the deuterium content of water extracted from chlorite is similar to that from biotite in the same rock. Irving Friedman and K. J. Murata have started an investigation of water and deuterium in basaltic glass collected during the 1959-60 eruption of Kilauea. The glasses show progressive enrichment in water content with increasing SiOz and K20 contents. The deu- terium concentration varies inversely with water con- tent of the glass. Fractionation of oxygen isotopes between dolomite and calcite Wayne Hall and Irving Friedman find that, in the system calcite and dolomite in equilibrium with water at low temperatures, the calcite and dolomite have the same 018/016 ratio within :02 percent. This was determined by analyzing many samples of Mississip- pian rocks from Illinois and Wisconsin, as well as partially dolomitized limestone from California and Nevada. Samples of finely intergrown calcite and dolomite ranging from pure calcite to pure dolomite give the same 018/016 and C13/C12 analyses, irrespective of the proportions of calcite to dolomite. Dolomite sep- arated from the mixtures by leaching of the calcite also gives the same 018/016 and Ola/C12 values. Use of oxy- gen isotopes in studies of lead-zinc and fluorite deposits NUCLEAR STUDIES A—81 of the Upper Mississippi Valley is described on page A—96. Fractionation of oxygen isotopes as a geologic thermometer The fractionation of oxygen isotopes between co-pre- cipitated minerals as a function of temperature is being investigated by R. N. Clayton and H. L. James. From analyses of minerals formed in equilibrium in natural environments several tentative equations have been de— rived relating temperature (T, in degrees Kelvin) to the equilibrium constant (K) ; for example, for an equi- librium pair quartz (Q)—magnetite (M) : Z’fl KQM=3216 7L2 Isotopic analyses have been made of mineral pairs from Precambrian iron-formations in different metamorphic zones of the Lake Superior region. The temperatures obtained from the data are consistent and geologically reasonable for rocks formed in the chlorite, biotite, and garnet zones; maximum values are as follows: Chlorite zone __________________ 200° C Biotite zone ____________________ 275° C Garnet zone ___________________ 350° C The apparent temperatures of formation of rocks formed\at higher metamorphic levels are inconsistent both within themselves and with geologically estimated temperatures of origin; this is attributed to retrograde alteration during the period of temperature decline. LEAD ISOTOPES R. S. Cannon, A. P. Pierce, J. C. Antweiler, and K. L. Buck (1961) have summarized the available data on the isotopic variations of ore-lead and their relations to processes of ore deposition. In a continuation of their studies, systematic variations in the relative abun- dance of lead isotopes in successive growth zones of a single crystal of galena from the Picher-Miami area, Oklahoma, have been related to changes in ore-forming solutions during mineralization. STUDIES OF VOLC‘ANIC GLASS Analyses of water and of fluorine in rhyolitic glass by Irving Friedman and Joseph Harris (Art. 258) Show that during hydration of obsidian the fluorine content is not appreciably affected. The fluorine con- tent of glasses appears to be remarkably uniform within a magmatic province, but changes from prov- ince to province. H. A. Powers (Art. 111) has used chlorine-fluorine content as a criteridn in correlating beds of volcanic ash in the Snake River Plain, Idaho. William Long and Irving Friedman are studying the effects of the hydration of obsidian at 400° C with different water pressures. The refractive index of obsidian increases with the water content in the range of 0.1 to 1 percent of H20, but then levels off and de- creases with water content in range 2 to 4 percent. A—82 R. L. Smith, I. Friedman, and W. Long are continu- ing experimental studies on welded tuffs. The rates of welding and compaction of rhyolitic ash and pumice were determined as a function of water pressure (0 to 300 psi), temperature (435° to 835° C), and load (up to 528 psi). SOLID-STATE STUDIES Luminescence and thermoluminescence studies In a study of the mechanism of luminescence due to alpha particles in minerals, P. Martinez and F. Senftle have determined the variation of the intensity and the decay time of the luminescent pulses with temperature for pure cesium iodide and also for cesium iodide con- taining about 0.1 percent of thallium as an impurity. Thermal luminescence measurements show that the scintillation produced in the activated crystals results from an electron-trapping mechanism. Radiation-damage studies T. Pankey and F. E. Senftle are investigating nat- ural radiation—damage processes in zircon and uraninite. Because radiation damage changes the oxidation state of the iron in the mineral, the natural iron impurity can be used as a tracer. The different oxidation states have specific magnetic properties, and hence the effects of damage can be analyzed by magnetic measurements. By use of such an analysis they have found that about 1,500 atoms are displaced in zircon by a single alpha particle and the recoil of the uranium nucleus. Ther— momagnetic measurements on pure iron oxides verify the results found in zircon and uraninite. Magnetic properties of ice In a study of the magnetic properties of cancer cells, F. E. Senftle and Arthur Thorpe (1961) have dis- covered that an observed magnetic difference between frozen cancer cells and frozen normal cells is due to the state of ice in the cells. Amorphous ice forms in normal cells and crystalline ice forms in cancer cells. In a continuation of this research they have discovered that water can be frozen so quickly that no crystal structure develops. The magnetic properties of rap- idly frozen, amorphous ice and crystalline ice are almost the same as those determined for the corresponding kinds of ice in normal and malignant tumor tissue. The amorphous ice that forms in normal tissue can be explained by the rapid cooling brought about by the large effective surface area of the cells. In con- trast, the water in tumor tissue apparently has a smaller effective surface area. The cooling is there- fore slower and only crystalline ice can form. These findings have application in the study of hydrous minerals. GEOLOGICAL SURVEY RESEARCH lQGl—SYNOPSIS OF RESULTS DEUT'ERIUM AND TRITIUM IN FLUIDS The origin, past history, and movements of water can frequently be determined by studies of the deu- terium and tritium contents. In particular, natural tritium may be used to estimate the age of water up to about 50 years, and fallout tritium provides a start- ing date for measurements of recent water movements involving a few months or years. Tritium measurement technique The measurement of tritium in water consists of four operations—electrolytic enrichment of the sample, measurement of deuterium, conversion of the sample to gas, and lo wbackground counting of the tritium radioactivity. After research into the effects of current density, voltage, and temperature, L. L. Thatcher has designed an electrolysis plant. that achieves 75 percent (:5 percent) tritium recovery when electrolyzing from 200 ml to 1 m1 under controlled current and low tem— perature conditions. Counting research involved analysis of various gaseous quenching agents for their ability to minimize multiple discharge in a hydrogen atmosphere. Ethyl and methyl ethers and ethylene were found to be superior to propane, acetone, ethyl alcohol, propylene, and benzene. Dimethyl ether shows the curious effect of superior quenching ability at higher hydrogen pressures. Below 20 cm of hydrogen the dimethyl ether was ineffective but at 2 atmospheres pressure it was the most effective. Ethyl ether is effec- tive at the low pressures. These improvements in elec- trolysis and counting techniques permit measurement to i 10 percent error on a routine basis. Fallout studies In a joint project with the US. Weather Bureau, fall- out of tritium from the early 1958 weapons test in the Pacific was measured at 12 stations extending in a north- westerly are from Puerto Rico to Alaska. Sample col— lection began in early April before the American tests series commenced. Fallout levels in the interior of the country, however, were already up to 200 tritium units (1 TU =1 T atom/1018 H atoms). A further increase to about 500 TU was observed in May and June. In July, when the sampling ended, the decay side of the fallout curve had not yet been reached. Central inland locations had the highest average tritium levels, about 500 TU through the peak fallout period, and coastal locations had the lowest average levels—about 100 TU. This difference is attributed to the dilution of the fallout by the relatively dead oceanic moisture; confirmation of this is given by the amount of chloride in precipitation, which is uniformly high along the coast and at a minimum inland. This study shows that tritium fallout is very unevenly distributed and is not uniform for the country. HYDRAULIC AND HYDROLOGIC STUDIES At the Wharton Tract in New Jersey, Carlston, Thatcher, and Rhodehamel (1960) , have found through studies of tritium that virtually all the ground-water discharge into the Mullica River entered laterally from its bank and just below the water table. This supports the deduction that streams in areas of horizontally bedded sediments receive most of their base-flow drain- age from beds lying above the bottom of the stream. Arabian studies Studies in Arabia by Glen F. Brown have established that in general the Arabian rainfall has followed the same tritium pattern as that of the United States with high values in} 1958 and the spring of 1959. Tritium, apparently of natural origin, has been measured by L. L. Thatcher in water from wells in the Wadi alluvium, and ages of the order of 10 years have been established. No tritium could be detected in water from wells penetrating deep aquifers such as the Minjur and Khobar formations, which means that the water has been below the surface for more than 50 years. Some of these samples may have been below the surface for as much as 20,000 years according to carbon-14 analyses by Meyer Rubin. Model studies Interpretation of tritium data requires knowledge of the physical and chemical isotopic effects of the environ- ment on tritium behavior, which is difficult to analyze in field studies because of the complex interaction of all factors. Therefore, these effects have been analyzed independently by a series of laboratory model studies. In a small model at controlled temperature it was found that the evaporation fractionation decreased with temperature rise. At room temperature Price’s value for tritium fractionation of 0.85 between the vapor and the liquid was confirmed. The exchange of HTO with H20 in montmorillonite was found to be attended by little fractionation, which shows that the adsorption of tritium by clays is rela— tively unimportant in problems of groundwater move- ment. Laboratory tests by Thatcher (Art. 432) on a number of dyes showed several that behaved with relatively little adsorptive holdup. Fast Crimson, in particular, performed in a manner analogous to tritium in montmorillonite column tests. This dye seems to be a good visual tracer to accompany tritium in hydrologic laboratory model tests. DISTRIBUTION OF RADIONU(71211331338I IN WATER. Knowledge of the occurrence and distribution of radioactive elements in surface and ground water bears on many problems relating to geochemical and A—83 hydrologic processes, disposal of radioactive wastes, and public health. In a reconnaissance investigation of the occurrence and distribution of uranium and radium in ground waters of the United States, R. C. Scott and F. B. Barker (Art. 414) found that the concentrations of radium were unusually high (>3.3 picocuries per liter) in: (a) formations of Cambrian and Ordovician age in the North Central States, (b) the Roubidoux and Cotter formations in Kansas and Oklahoma, and (c) the Chey- enne sandstone member of the Purgatoire formation in southwestern Colorado. The concentrations of radium in water within a formation generally increase in the presumed direc- tion of ground-water movement and may be a result of the slow flushing of radioelements. F. B. Barker and R. C. Scott (Art. 128) have found that concentrations of uranium and radium in ground water from individual terranes of the Pacific North- west tend to be distributed according to log-normal probability laws. The geometric mean of the distribu- tion is controlled by both geologic and climatic factors. Concentrations of these radioelements tend to be higher in water from the more silicic terranes. In regions of high annual precipitation the concentrations are lower than in semiarid regions. Agricultural development of the Snake River Plain apparently has resulted in higher concentrations of uranium in most water of the area, but has had little effect on the concentrations of radium. In studies of the concentration of radium and ura- nium and amount of radioactivity in ground water from Rainier Mesa, Nevada Test Site, Alfred Clebsch and F. B. Barker (1960) have found that the natural level of beta activity in the ground water of the area is less than 25 picocuries per liter. (See also p. A—90.) HYDRAULIC AND HYDROLOGIC STUDIES Studies of amounts and movements of water, both on the surface and underground, are important in plan- ning flood control, hydro-electric and municipal water supply projects, in studies of contamination, and in development of new supplies of water for present and future use. Most of the hydraulic and hydrologic studies carried on during the year were directly ap- plicable to work in individual regions or on particular topics and are described in other parts of this report. A few findings of broader application are summarized below. OPEN-CHANNEL HYDRAULICS AND FLUVIAL SEDIMENTS Many aspects of open-channel flow have been studied by analysis of laboratory and field observations. In— A—84 cluded are studies of steady and unsteady fl0w in stable and unstable channels of uniform or gradually varied configuration, flume studies, and studies of the effects of urbanization on the amount of sediment in streams. Distribution of velocity By laboratory study, H. J. Tracy and C. M. Lester have defined the distribution of velocity in smooth rec- tangular channels in terms of the average shear on the bed and the aspect ratio of the channel. Within the zone of influence of the side walls, the maximum velocity on a vertical profile is below the water surface. Outside this zone the vertical velocity profile follows the logarithmic law advanced by Karman and Prandtl. Resistance to flow The relation between the Manning roughness coeffi- cient and the Froude number or energy slope developed by C. M. Lester (Art. 159) is identical to that predicted by a resistance equation of the Karman-Prandtl form, if the viscosity is constant. In the general case, the coefficient for a smooth channel varies with the Rey- nolds number and the hydraulic radius. By laboratory studies W. W. Emmett (Art. 158) has shown that piezometric measurements of depth of flow in open channels are always greater than actual depth because of vortex action in the piezometer hole. The vortex action and the amount of error increases as the hole size or the velocity increases. The error ranges typically in supercritical flow from 1 to 6 percent. H. J. Koloseus and J. Davidian (Art. 12) have de- fined the resistance to flow of cubical roughness elements in terms of the relative height and concentration of the cubes. The equation that expresses the relation is simi- lar to the Nikuradse equation for sand-roughened pipes. The height and the concentration of roughness elements are equally important in determining the overall re- sistance to flow. Boundary form and resistance to .flow in alluvial channels The forms of bed roughness that may occur in allu- vial channels as the boundary shear stress is increased have been classified by D. B. Simons and E. V. Rich- ardson as ripples, ripples superposed on dunes, dunes, the transition zone in which the dunes are eliminated, plane bed, symmetrical sand waves, and antidunes. When the bed roughness consists of ripples, ripples superposed on dunes, or dunes, the undulations induced in the water surface are out of phase with the bed roughness and the resistance to flow is relatively large. With these conditions, flow is said to be in the lower regime of flow. After the transition zone is passed and the forms of bed roughness become plane bed, sym- metrical sand waves, and antidunes, the resistance to flow is relatively small and flow is said to be in the up- GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS per regime. Thus, the regime of flow is controlled by the form of bed roughness and resistance to flow. Changes in slope, fall velocity of sediment, or depth of water can change the form of bed roughness, the resistance to flow, and the sediment discharge. Laboratory studies by Simons and others (Art. 165) have demonstrated that changes in the form of bed roughness and resistance to flow significantly affect stage—discharge and depth-discharge relations. The maximum effect occurs when the bed roughness changes from the lower regime condition of dune t0 the upper regime of plane bed, symmetrical sand waves, and antidunes. ‘ Significance of fine sediment on flow phenomena in alluvial channels An increase in the concentration of fine silt and clay in streams increases the apparent viscosity and specific gravity of the stream liquid, and thus decreases the fall velocity of the bed-material particles. Haushild and others (Art. 300) have shown that at 20° C a 5— percent (by weight) aqueous dispersion of bentonite is about 2.5 times more viscous than distilled water. They have also shown that a decrease in fall velocity increases bed roughness and resistance to flow, and decreases the amount of sediment transported. Efl'ects of temperature on flow phenomena in alluvial channels D. W. Hubbell and others (Art. 301) have verified by flume experiments that an increase in the tempera- ture of a stream liquid decreases its viscosity and thereby increases the fall velocity of the bed material. If the increase in temperature and the concomitant increase in fall velocity are sufficiently large, a plane bed may be changed to a dune bed, thereby increasing resistance to flow and decreasing the amount of mate- rial transported. Efi'ect of depth of flow on total discharge of bed material Computations made by B. R. Colby and D. W. Hubbell (1961) with the Einstein procedure and with an empirical analysis of data from flumes and natural streams, show that at constant low mean velocity an increase in depth reduces the bed—material discharge; whereas, at constant high mean velocity the effect of depth is reversed. At some intermediate velocity, the effect of changes in depth is usually small, but the depth effect is large throughout the usual range of significant flows in natural streams. Solution of unsteady-flow problems R. A. Baltzer and J. Shen (Art. 162) have developed a solution for a system of unsteady-flow equations by means of power-series expansions through an iteration process. Results of computations for discharges HYDRAULIC AND HYDROLOGIIC STUDIES through a reach of the Sacramento River compare closely with the measured discharges. Detailed measurements of velocity during a tidal cycle on the Delaware River were obtained by E. G. Miller. He found that the mean velocity of flow in the cross section could be related to velocity at a single point. Thus, a continuous record of tidal discharge can be obtained from continuous records of point ve- locity and stage. Size and distribution of bed material in the Middle Rio Grande, New Mexico An analysis of stream-bed material from the Middle Rio Grande at eight sites in a 190-mile reach of river between Otiwi Bridge near San Ildefonso, and San Marcial, N. Mex., by C. F. Nordin and J. K. Culbert- son (Art. 265) showed that the bed material ranged from sand and gravel in the upper reaches to sand in the lower reaches. Analysis of the samples indicates that the size distribution of bed material in the lower reaches of the river is relatively independent of flow. In the upper reaches, the characteristics of the bed material changed with discharge. Above 2,000 cubic feet per second, the median diameter of the bed mate- rial increased with increase in discharge. Below 2,000 cubic feet per second, the size distribution of bed ma- terials was relatively independent of flow. Also, the bed material in the upper reaches had a bimodal distribution. Effects of urbanization on the supply of fluvial sediment H. P. Guy has appraised quantitatively the influence of urbanization on the amount of sediment moved by streams. In rural areas, the concentration of suspended sediment during periods of runoff usually ranges from 200 to 400 ppm. During the period of transition to an urban area when houses are being built and streets are being graded, the amount of suspended sediment in periods of runoff is very high, and may average as much as 36,000 ppm. Usually, a year or two after the development on a given area has been completed, the sediment yield declines to a small fraction of that occurring during construction. SURFACE-WATEER HYDROLOGY Surface-water hydrology involves measurements of streamflow, and parallel studies of the relations between streamflow and the characteristics of drainage basins and meteorologic factors. The establishment of such relations will enable streamflow to be predicted from physical and meteorologic factors alone. It will also lead to the prediction of changes in streamflow caused by changes in physical conditions, such as changes in land use or the degree of urbanization. 608400 0—61—7 A—85 Errors in streamflow measurement In examining the accuracy of current-meter measure— ments, I. E. Anderson (Art. 161) has found that the total error attributable to assumptions involved in the use of the current meter is less than 3 percent for two— thirds of measurements made by standard methods. Use of precipitation in analysis of runoff data The relation between runoff in two drainage basins is often used to fill in missing periods of record or to ex- tend the length of record for one of the basins. The re- lation can be improved and the length of streamflow record greatly extended by also considering differences in precipitation (Schneider, Art. 9). H. C. Riggs (Art. 42) has used a relation of annual minimum streamflow with two precipitation indices to demonstrate that the three lowest annual minimum pe- riods of streamflow on the Tallapoosa River, Ala., dur- ing a relatively short period of record were probably also the three lowest in a longer period covered by the precipitation record. Low flow A study by Riggs (Art. 10) of annual minimum 7- day average flows of streams in the eastern United States has led to a generalized relation that defines the 20-year low in terms of the 2-year low, the drainage- area size, and the slope of the recession curve of dis- charge. This study was based on 47 stations; the rela— tions developed were applied to 61 other stations in widespread parts of the United States and Turkey and seem to fit equally well wherever tested. Peak flow M. A. Benson (1961) investigated the relation of peak discharge to hydrologic characteristics in a humid region in New England. Annual momentary peak dis- charges of recurrence intervals ranging from 1.2 to 300 years were found to vary with six topographic and climatic factors. D. R. Dawdy (Art. 160) has found that the ratio of a flood of given recurrence interval to the mean or median annual flood varies inversely with the size of the drainage area. STATISTICAL METHODS Effect of interstation correlation N. C. Matalas and M. A. Benson have studied the effect of interstation correlation (as, for example, where annual peak discharges on several basins are caused by the same storms) on regression relations be- tween peak discharges and a hydrologic factor. They have demonstrated on statistical grounds that interde- pendence between the discharges for different stations increases the variance of the regression constant, de- creases the variance of the regression coefficient, and A—86 may decrease but usually increases the variance of a predicted value of the dependent variable. These find- ings shed light on the reliability of predicted stream- flow of a given recurrence interval and relations of streamflow with hydrologic characteristics. Statistical properties of a runoff precipitation relationship An investigation has been made by N. C. Matalas of the influence of the water—retardation characteristics of a river basin on the distribution of the runoff. The runoff was taken to be generated by a moving average of the effective precipitation Where the time interval of the moving average is assumed to be equal to the carry- over period, which is a function of the water-retarda- tion characteristics of the river basin. The probability distribution of the runoff was found to be a function of the time interval of the carryover period. Since the water-retardation characteristics vary from one river basin to another, even though the characteristics of the effective precipitation may be the same for each river basin, the probability distribution of the runoff is not the same for all river basins. Owing to the carryover period, the runofl' is non— randomly distributed in time. The serial correlation coefficients measuring the, nonrandomness of the runoff are functions of the coefficients of the moving average model under the assumption that the effective precipi— tation is randomly distributed in time. Statistical evaluation of tree-ring data Trees growing on well—drained sites where rainfall is the limiting climatic factor influencing growth, con- stitute a source of hydrologic information. In an investigation of the statistical characteristics of tree-ring indices, N. C. Matalas has shown that at any given time the mean annual growth is proportional to the standard deviation. Thus, the coefficient of variation serves as a measure of the sensitivity of growth to variable hydrologic conditions. Matalas also showed that averaging of indices for several trees results in a loss of information, and that tree-ring indices are nonrandomly distributed in time. Cor- relogram and power spectra analyses made for a 450- year old pinon pine from the upper Gila River basin near Beaverhead, N. Mex., indicated that the non- randomness was due to a “storage” efl'ect rather than to ridden periodicities. The serial correlation coeffi- cients of tree—ring indices were found to be much larger than those for annual rainfall and to varry with the species. This variation suggests that the biological components influencing growth contribute to the non- randomness of the tree-ring indices. GEOLOGICAL SURVEY RESEARCH lQfil—SYNOPSIS 0F REISULTS Low flow probability distribution Analyses were made by N. C. Matalas to determine which theoretical probability distribution best fitted observed values of low flow and to determine the desir- ability of estimating the parameters of theoretical prob- ability distributions by the method of maximum likelihood. Four theoretical probability distributions were studied: (a) Gumbel’s limited distribution of the smallest value; (b) the Pearson Type III distribution; (0) the Pearson Type V distribution; and (d) the 3- Parameter Log—Normal distribution. Applicability of each of these four theoretical prob- ability distributions to low-flow data, was measured by two criteria. The first criterion was based on the relation between the observed minimum low flow and the lower limit of the theoretical probability distribu- tion. The second criterion was based on the observed relation between skewness and kurtosis with respect to the relation between skewness and kurtosis for the theoretical probability distribution. The Gumbel and the Pearson Type III distributions were found equally applicable and more representative than the Pearson Type V or the 3-Parameter Log-Normal distributions. The above conclusions were based on moment esti- mates of the various statistical parameters. An alter- nate method of estimating the parameters so that their variances are a minimum is that of maximum likeli- hood. The variances of the moment and maximum likelihood estimates are functions of the skewness of the data. The average skewness for the low-flow data was found to be approximately 1; whereby, the vari- ances of the moment estimates were nearly twice as large as the variances of the maximum likelihood esti— mates. Thus, the method of moments utilizes only half of the available information in a set of low-flow data. On the other hand, the complexity of the method of maximum likelihod requires the use of high—speed electronic computers. Reservoir storage—general solution of a queue model The application of queuing theory to reservoir stor- age problems usually leads to a set of simultaneous linear equations that must be solved for each specific case. By assuming that random inflows during suc- cessive units of time are approximated by a trinomial probability distribution, W. B. Langbein (Art. 298) derived a general solution for the set of simultaneous linear equations. Calculations for the probability of spilling and being empty are based on two cases—a normal distribution of inflow, and a logarithmic normal distribution of inflow having a skew equal to 1.0. EVAPOTRANSPIRATION Fluctuation of annual river flows V. M. Yevdjevich has made a statistical study of the fluctuation of annual runoff and effective annual rain- fall, based on records for 140 river gaging stations throughout the world. A comparison was made of the statistical properties of annual runoff and effective annual rainfall with the statistical properties of ran- dom time series and time series generated by a moving- average process. Yevdjevich concludes that much of the difference between the observed hydrologic time series and purely random time series can be attributed to regression effects due to the year-end carryover of water, snow, and ice, and to the inconsistency and non- homogeneity of the. data. MECHANICS 0F FLOW THROUGH POROUS MEDIA A theory of infiltration by W. O. Smith attributes fluid movement through unsaturated porous media to a process of layering and sheet flow. The process is believed to be influenced by the detachment of capillary bodies as movement progresses toward the water table. R. W. Stallman (Art. 28) has completed a preliminary design of an electric analog to simulate terms in the equation that describes one—dimensional flow of fluid through unsaturated porous media. The analog will permit analysis of fluid movement through nonhomo— geneous profiles under various boundary conditions. H. R. Henry (1960a, b) has derived mathematical formulas for describing the distribution of head and salinity in the fresh-water—salt-water zone of disper- sion in a confined coastal aquifer in which there is steady seaward flow of fresh water. The results con- firm a cyclic flow of salt water from the sea floor into the zone of diffusion and back to the sea, thereby lessen- ing the extent to which salt water occupies the aquifer. W. K. Kulp and H. H. Cooper have evaluated, through laboratory experimentation and analysis, the dispersion coefficients associated with saturated granular materials subject to reciprocative fluid movement. The results show that the coefficients for this type of flow are vir- tually the same as for unidirectional flow. H. E. Skibitzke (19600) has demonstrated with hy- draulic experiments on artificial sandstone models that three-dimensional fluid flow through heterogeneous regions in porous media is characterized by considera~ ble intertwining of the flow lines. He concludes that the heterogeneity causes the fluid to spread out. as it moves and that the ordinary processes of diffusion and dispersion are not significant by comparison. J. A. da Costa and R. R. Bennett (1960) have derived the mathematical equations describing the steady-state flow patterns in the vicinity of a pair of wells, one of ,A—87 which is recharging and the other is discharging, in a region of preexisting one-dimensional ground—water flow. The equations permit determination of the inter- flow between the recharging and discharging wells in terms of the orientation of the wells with respect to the direction of preexisting regional flow, the rate of re- charge or discharge per unit length of well bore, the distance between the two wells, and the preexisting velocity of the regional ground-water flow. LIMNOLOGICAL PROBLEMS Salinity of closed lakes In some closed lakes the salt in solution is less than 1 percent by weight; in others, the salt in solution exceeds 25 percent. In all closed lakes the tonnage of dissolved salts is substantially less than the total input of salts over the life of the lake. In a study of 25 lakes in many parts of the world, W. B. Langbein has found that a significant part of differences in salinity can be explained in terms of lake area, the variation in lake area, mean depth, rate of evaporation, tributary area, and the volume between the lake level and the level of overflow. Preliminary analyses by L. B. Laird of water from Lake Abert, a closed lake in south-central Oregon, show concentrations of dissolved solids ranging from 10,000 to more than 50,000 parts per million. Sodium, carbonate, bicarbonate, and chloride are the principal constituents. Significant amounts of silica, potassium, bromide, phosphate, and boron are also present. Pleistocene lake levels as indicators of climatic shifts The ratios of precipitation to evaporation in the Basin and Range Province during Pleistocene time have been determined by C. T. Snyder and W. B. Lang- bein to have been at least 35 percent greater than present ratios based on a consideration of the high levels at- tained by former Pleistocene lakes. EVAPOTRANSPIRATION The energy-budget method of measuring evapotrans— piration has been tested by O. E. Leppanen and G. E. Harbeck, Jr. (1960) at a site in Nebraska. A water- budget control was used so that evapotranspiration could be determined from measurements of rainfall and changes in soil-moisture storage. There was no runoff from the area. Ground water was too deep to supply any water to the vegetation. Evapotranspira- tion computed from the energy budget was somewhat greater than that computed by the water budget. The accuracy of the evapotranspiration figures computed by the energy-budget method was found to depend to a large extent on the accuracy with which the inter- A—88 change of sensible heat between the atmosphere and the vegetation can be measured. GEOLOGY AND HYDROLOGY APPLIED T0 PROBLEMS IN THE FIELD OF ENGINEERING Some of the Survey’s work is designed to provide geologic and hydrologic information that is directly applicable to the solution of engineering problems, such as construction of dams, roads, public buildings, damage caused by earthquakes, landslides, and erosion, or stud- ies in connection with underground testing of nuclear explosives. A few examples of such applications, some done at the request of other Government agencies and some as outgrowths of the Survey’s regular program, are described here. In addition to these specific applica- tions, most of the Survey’s maps and reports contain information that is useful to engineers. CONSTRUCTION PROBLEMS The Survey’s work on construction problems during the past year has been concentrated on urban and high- way construction, tunnel investigations, and related research. Urban geology As a byproduct of urban investigations that have been in progress in the San Francisco Bay region for some years, records of 456 wells and test borings made on the east side of San Francisco Bay were released to the public (Weaver and Radbruch, 1960). In the cities of Omaha, Nebr., and Council Bluffs, Iowa, R. D. Miller has reported the discovery, by means of auger drilling, of a limestone bench within reach of end-bearing piles beneath the flood plain alluvium of the Missouri River. With alleviation of flood threats by the completion of major dams upstream, this dis- covery may well change hitherto useless land into suita- ble sites for industrial plants. D. J. Varnes made an analysis of full-scale load tests of foundation caissons set in sandy silty gravel at the Air Force Academy site near Colorado Springs, Colo. This analysis showed that settlement cannot be predicted according to the classical theory of consolidation but is better handled by the theory of creep, and is closely analogous to chem- ical kinetic-rate theory. It was found that some tests very nearly followed Andrade’s law of creep and that most approached a rate at which settlement varied linearly with the logarithm of time. Extrapolation of the tests to 10 million minutes indicated a linear relation between log load and log settlement. Highway geology in Alaska Contributing to studies of highway geology in Alaska, which are carried on in cooperation with the Bureau of Public Roads, T. L. Péwé and S. W. Holmes GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF REISULTS have mapped the Mount Hayes D—3 and D—4 quad- rangles near Big Delta. They found that late Pleisto- cene moraines have been displaced as much as 15 feet by recently active faults, a factor that must be taken into account by road builders. They also report that the great depth of seasonal freezing in gravel outwash plains may be mistaken for permafrost. Other highway geology studies in the Yukon-Koyu- kuk lowland by F. R. Weber and T. L. Péwé (Art. 419) will aid the Bureau of Public Roads in road location and construction through a most difficult and complex area of perennially frozen ground. Destruction by flood of the Sheep Creek bridge on the Richardson Highway focussed attention on the threat of floods from sudden drainage of ice—dammed lakes in the Chugach Mountains. Investigations by H. W. Coulter have revealed 8 such lakes, which im- peril 5 bridges and 3 miles of highway. Relocation of bridges and realinement of parts of the road seem to be the best means of avoiding future disasters. Harold D. Roberts tunnel E. E. Wahlstrom, L. A. Warner, and C. S. Robinson (Art. 131) are correlating geologic features with engi- neering problems in the new Roberts water tunnel, which extends 23.3 miles under the Continental Divide near Denver, Colo. They have found that spalling rock which required heavy support is fresh, brittle, compe- tent rock that occurs between bodies of weaker rocks or is bounded by faulted or fractured rock masses. Other areas requiring support are those passing through zones of layered rock, faults, joints, and clay alteration. Subsidence Subsidence of the land surface leads to various engi- neering problems whose solution requires an under- standing of the geologic and hydrologic processes in- volved. During the course of studies of subsidence in the San Joaquin Valley, Calif, W. B. Bull (Art. 77) has found that near-surface subsidence on certain alluvial fans results chiefly from compaction of mate— rial by overburden as the clay bond in the sediments is weakened by water that percolates through them for the first time after their deposition. Other findings in the study of subsidence are sum- marized under the heading, Effects of fluid withdrawal, beginning on page A—71. Clays for canal lining To aid in the search for low-cost canal lining mate— rial, B. N. Rolfe, R. F. Miller, and I. S. McQueen (1960) have studied the chemistry of the system—clay, water, ionized salt. They found that with the proper chemical dispersing agents, montmorillonite-type clays GEOLOGY AND HYDROLOGY APPLIED T0 PROBLEMS IN THE FIELD OF ENGINEERING are relatively superior for penetrating and filling of small voids. On the other hand, kaolinite and illite clays, properly dispersed and allowed to settle from canal waters, may be suitable for filling joints, cracks, burrows, and other relatively large openings. Measurement of displacement during hydraulic fracturing of rock In tests of the feasibility of fracturing shale under— ground by hydraulic methods in order to obtain space for the storage of atomic wastes, a liquid-level tiltmeter described by F. S. Riley (Art. 136) has been found ca- pable of measuring significant tilting at distances as far as 243 feet from the injection well. This method of measurement may have useful application in controlling grouting for ordinary construction purposes. ENGINEERING PROBLEMS RELATED TO ROCK FAILURE Landslides In the Pacific Palisades area of Los Angeles, detailed mapping by J. T. McGill has revealed the relation of landslide distribution to geologically recent tectonic activity. Differential uplift of the major late Pleisto- cene marine terrace has caused faulting and warping of the wave—abraded bedrock platform and its veneer of marine and nonmarine sediments. Movement of ground water within the sediments is controlled pri- marily by the slope of the platform. Seepages and asso- ciated landslides tend to occur where the bedrock plat- form is inclined outward from canyon walls and sea cliffs. The relation between landsliding and steep slopes that result from tectonic activity is illustrated by slides at the eastern base of the Funeral Mountains, Calif., de- scribed by C. S. Denny (Art. 323), and by slides along the Uinta fault in Utah described by W. H. Hansen (Art. 132). The slides along the Uinta faultline scarp are abundant where the northerly exposure minimizes insolation, and where moisture accumulates. Many landslides, some of them exceptionally large, have been mapped in Puerto Rico. In the southern part of the island, very large debris slides described by P. H. Mattson have moved along a bedding plane of granular breccia. In north—central Puerto Rico, numerous slides occur at places where thick limestone units are underlain by beds of clay; one such slide involves more than 43 million cubic meters, or about 100 million tons of rock. Movement and growth of in- dividual slides is continuous, but the toes tend to move so slowly that houses and roads are reasonably stable. Further studies of the Slumgullion earthflow in southwest Colorado by D. R. Crandell and D. J. Varnes (Art. 57) have shown that the active part is A—89 moving at a rate of 20 feet per year in midsection to 2.5 feet per year at the toe. lomparison of aerial photographs made in 1939 and succeeding years to- gether with direct measurements since 1958 indicate that the rate of movement has been essentially uniform for 20 years. Rock mechanics as related to mining engineering In studies of coal mine bumps, F. W. Osterwald (Art. 274) has found that most of the local deforma- tional features in the Sunnyside No. 1 coal mine, Car- bon County, Utah, are the result of lateral rather than vertical compression. Detailed mapping of the de— formed rock, coal, and supports indicates the local dis- tribution of compressive and tensional stress and aid in design of roof—control measures. EROSION Measurements by R. F. Hadley (Art. 16) in drain- age basins in the High Plains have shown that north- erly facing slopes are generally steeper, less dissected, and support a denser vegetation cover than southerly facing slopes, owing to differences in insolation, rate of melting of snow, and evaporation. Erosion is more rapid on southerly facing slopes, and the resultant debris displaces the main channel southward from the central axis of the basin. Other studies of land-form analysis (Schumm and Hadley, 1961) may apply to erosion problems throughout the semiarid parts of western United States. G. C. Lusby (Art. 59) has found that runoff and sediment yield from grazed watersheds have been as much as twice that from similar ungrazed watersheds at Badger lVash, western Colorado. The sediment is apparently derived in large part from the deepening and widening of gullies rather than from the hillsides. I. S. McQueen (Art. 14) has made a laboratory inves— tigation of the physical properties of soil material that may influence erodibility. He has shown that, in gen- eral, a poorly sorted sediment with a small median grain size will resist erosion by water flowing at 1.2 feet per second better than a well-sorted sediment with a larger median grain size. The effect of grain-size distribu- tion is, however, less important than factors related to packing, such as bulk density, structure, texture, cemen— tation, porosity, and pore-size distribution, and the past history of wetting and drying. Samples that were dry- packed and then wetted to field capacity water content eroded from 2 to 400 times as fast as samples of the same material at approximately the same water content but which had previously been puddled. C. A. Kaye’s continuing study of the erosion at Gay Head, Martha’s Vineyard, Mass, indicates that the cliff headland has probably receded about 4,000 feet in the A—90 past 3,000 years. The average retreat of the north end of this scenic exposure has been 1.8 feet per year during the last 75 years. Remedial measures that might be ap- plied include drainage of swamps and depressions be- hind the cliff, dewatering by wells, and local protection of the cliff base by riprap (Kaye, 1961). R. P. Briggs (1961) has found that rapid and de- structive shoreline changes at Puerto Arecibo on the north coast of Puerto Rico are relatively recent phe- nomena. Field studies of the patterns of erosion and sedimentation and comparison of maps and aerial photo- graphs covering the period 17 91—1959 have shown that the shoreline was generally stable until 1940. A break- water was constructed in the period 1940—42 in order to form a protected harbor. Most other factors have been essentially the same from at least the latter part of the 19th century until the present. Hence, the breakwater and dredging in the harbor appear to have caused the shoreline modifications by altering the systems of waves and currents. Kenneth Segerstrom (1960a and Art. 370) has ob- served the erosion of ash at Paricutin volcano, Michea— éan, Mexico, periodically from 1946 to December 1960. He found that by 1957 the rate of stripping of the ash mantle had decreased markedly, owing largely to in- creasing vegetation cover. Observations in 1960 indi- cated continued deceleration of erosion and redeposition because the most vulnerable ash deposits had been stripped off the steeper slopes and from the main stream channels. Areas covered by ash or ash reworked by streams are now being rapidly covered by increasing numbers and varieties of trees, shrubs, and small plants. SELECTION OF SITES FOR POSSIBLE NUCLEAR TESTS AND EVALUATION OF EFFECTS OF UNDERGROUND EXPLOSIONS Sites for possible underground and cratering nuclear explosions have been selected by the Atomic Energy Commission partly on the basis of studies by the Geo- logical Survey. In addition to defining the geologic environment of possible sites, these studies have dealt with such problems as subsurface and surface water con- tamination by fission products, the containment and cratering of explosions, and the effect of structure and lithology on seismic energy distribution (Eckel, 1960a). Nevada Test Site The Nevada Test Site is the testing facility of the Atomic Energy Commission where performance of nu- clear explosives has been studied during past test opera- tions and where experimental nuclear reactors are being studied. The Survey advises the Commission on the geological aspects of its operations and has continued both general studies of the test site and special studies GEOLOGICAL SURVEY RESEARCH 196l—SYNOPSIS OF REISULTS of the geologic and hydrologic effects of contained and cratering explosions. Deep drilling to determine the occurrence, rate, and direction of movement of ground water beneath Yucca Flat continued in 1961; the water table or piezometric surface is 1,500 to 1,800 feet below the earth’s surface, and the altitude of water levels in wells indicates very low hydraulic gradients. Ground water moves thro’ugh Paleozoic bedrock, tutf of the Oak Spring formation of Tertiary age, and Quaternary alluvium. In both Frenchman and Yucca Valleys the observed water-level altitude is lowest in the deepest well, suggesting a de- crease in pressure head with depth and an important downward component of water movement. Although data are inadequate to estimate average rates and directions of ground-water movement, the tritium content of well water beneath Yucca and Frenchman Valleys and Jackass Flats as determined by Alfred Clebsch (Art. 194) indicates that the water in these basins has been underground 50 years or more. In marked contrast, tritium analyses of samples collected in August and September 1958, from the perched aquifer in Rainier Mesa and from the aquifer that discharges at Whiterock Spring indicate that the water in these up- land parts of the test site entered the ground since November 1952 and before January 1958. Chemical and radiochemical analyses of water samples obtained near the Logan and Blanca nuclear detonations of October 1958 showed the highest fission product content in the perched ground water within a few hundred feet of the blast points (Clebsch and Barker, 1960). Evidence of contamination was noted half a mile from the blast points, but samples 500 to 2,000 feet from the blast sites were not contaminated. Samples collected at points about 600 and 500 feet from the Logan and Blanca blast points, respectively, showed contamination in March 1959 but almost none in J an- uary 1960. Clebsch (1960) has concluded tentatively that the apparently erratic distribution of anomalous radioactivity in the perched water table resulted from expulsion of radioactive material along blast-produced fractures. Recent study of wells in the Nevada Test Site by J. E. Moore has shown that the altitude of the permanent water table in the major basins within the Nevada Test Site—Yucca and Frenchman Valleys and Jackass Flat~ranges from 2,386 to 2,553 feet above sea level but averages 2,400 feet for the three basins. The water table altitudes in the basins to the north, east, and west, however, are 1,500 to 2,200 feet higher. It is in— ferred, from these data, that the natural discharge areas are southwest of the test site. There are two main sources of water at the Nevada Test Site. One of these GEOLOGY AND HYDROLOGY APPLIED TO PROBLEMS IN THE FIELD OF ENGINEERING includes the Oak Spring formation, of Tertiary age, and the younger alluvial fill. The other consists of the carbonate rocks, shales, and quartzites of Paleozoic age. Chemical analysis of samples from both sources shows that the waters contain from 282 to 476 parts per mil- lion ‘total dissolved solids. The net extractable alpha and Sr 9° in water samples range from >01 to 6.8 MILO/1 and <.6 to 2.0 muc/ 1, respectively. J. W. Hood has demonstrated by aquifer tests that stored ground water in Frenchman and Yucca Flats will be adequate for many years at present pumping rates. As a result of geologic mapping and gravity surveys, the limits have been defined for a collapsed caldera 6 to 7 miles in diameter, in the western part of the Nevada Test Site. The caldera is the assumed source of the widespread, thick welded-tufl' sheets that make up the Oak Spring formation. Preliminary nomenclature for these volcanic rocks has been established by E. N. Hin- richs and P, P. Orkild (Art. 327). Large volumes of flow-banded rhyolite and basalt derived from vents along the peripheral fracture occur in the central part of the caldera. Locally extensive alteration of the vol- canics along the fracture suggests near-surface intrusive masses. Complex zeolites that make up as much as 45 percent by volume of the tui’f of the Oak Spring formation have been described by A. O. Shepard. (See p. A—72.) A prerequisite for evaluation of seismic signals gen- erated by a planned underground nuclear explosion in the Climax granitic stock, in the northern part of the Nevada Test Site, is an accurate picture of the size, shape, and geologic setting of the stock. From aero- magnetic data, Isidore Zietz and J. W. Allingham have shown that the stock is circular, has an approximate diameter of 4 miles at sea level (about 5,000 feet below the surface outcrop), and has a minimum thickness of 15,000 feet. Geologic mapping by F. N. Houser and F. G. Poole (Art. 73) and zircon age determinations have shown that the stock is composite, and was in- truded during Permian to early Mesozoic time. D. D. Dickey and R. B. Johnson (Art. 278) have shown that the long dimensions of the high-explosive craters in basalt roughly parallel the strikes of promi- nent, nearly vertical joints. The long, narrow areas of ejecta beyond the rims of the craters, however, are oriented nearly normal to the direction of these joints. Ejecta are sparse in the directions parallel to these natural joints. An adequate knowledge of the distri- bution and orientation of natural fractures may be an economically important factor in the utility of crater— ing explosions for industrial purposes. A—9 1 Plowshare program As part of the Atomic Energy Commission’s Plow- share program to develop peaceful uses for nuclear explosives, Project Gnome, near Carlsbad, Eddy County, N. Mex., is a proposed experiment to deter— mine whether thermal energy and valuable isotopes can be recovered from a nuclear explosion completely con- tained within a homogeneous salt mass. A geologic and hydrologic study of the area by J. B. Cooper (1960) has revealed that the salt mass is overlain by a single confined aquifer, the Culebra dolomite member of the Rustler formation, which is 518 to 550 feet below the surface and 150 feet above the salt sequence. The Culebra has a transmissibility of 4,000 gpd/ft (gal- lons per day per foot). ANALYSIS OF HYDBOLOGIC DATA Almost all hydraulic and hydrologic studies provide data that require interpretation and analysis, and many examples of such analysis have been summarized under other headings. Reported here are a few findings in each of several fields of research in which the results required new methods of analysis or very extensive analysis of large amounts of data. FLOODS A method of determining the probable magnitude and frequency of floods at any specific site in a defined region has been presented by Tate Dalrymple (1960). The method requires use of two diagrams, one in which the ratio of peak discharge to mean annual flood is related to recurrence interval, and the other in which the mean annual flood is related to size of drainage area and—for some areas—to other significant basin char- acteristics. From these two areal relations the relation between peak discharge and frequency of occurrence can be determined for a specific site. The size of the mean annual flood is generally related directly to the size of the drainage area. Other factors of local significance and the region where they are most applicable are as follows: (a) elevation of drainage basin (eastern Montana, Wyoming, Utah, and the Colo- rado River basin), (b) area of lakes and ponds (Florida, Minnesota, Wisconsin, Pacific Northwest, Delaware River basin), (c) mean annual runofl' (Kan- sas, Pacific Northwest), (d) geographical factor (Wis- consin, Pacific Northwest), and (e) lag factor (Illinois). In a study of flood-plain planning, S. W. Wiitala, K. R. Jetter, and A. J. Sommerville have presented a method of estimating probable flood risk by use of A—92 existing data on flood magnitude and frequency, stage discharge relations, and flood profiles. They outline a method of preparing inundation maps for floods of several magnitudes and frequencies for three stated positions: (a) near a gaging station, (b) at a consider- able distance from a gaging station, and (c) on an un— gaged stream. A summary of findings concerning the great flood of September 6, 1960, in Puerto Rico is presented on page A—47. GROUND WATER Studies by R. W. Stallman (1960) of the differential equation of simultaneous heat and water flow through an isotropic and homogeneous aquifer indicate that under natural conditions the direction and velocity of ground-water flow can be calculated for most aquifer systems, given only the temperature distribution in the aquifer. In a study of glacial-outwash aquifers near Worth- ington, southwestern Minnesota, Robert Schneider (1961) used temperature fluctuations of ground water to estimate the rate of movement of water from Okabena Lake to nearby wells and to detect the in- filtration of summer rainfall. Rates of movement ranged from about 2 to 6 feet per day under the prevail- ing gradients. IN’I‘ERRELATION BETWEEN SURFACE WATER AND GROUND WATER The movements of surface water and ground water are so closely related that alteration of one soon affects the other. Techniques employed to study the relation include analysis of ground-water hydrographs and con- tour maps; correlations of ground—water levels and surface-water stage or discharge; basin-water budgets; use of steady-state analog models, non-steady-state electronic computers, and mathematical models; graphical statistical analysis; and use of temperature or chemical constituents as tracers. Interchange of surface water and ground water under natural conditions Seepage rates along the lower reaches of 21 streams tributary to the Sacramento and lower San Joaquin Rivers, Calif., have been reported by S. E. Rantz and ‘ Donald Richardson (Art. 215). Most of the streams intermittently lose water to, or receive water from, the underlying aquifer. The annual runoff of the streams on the west side of the San Joaquin Valley is 60,000 acre-feet, of which 60 to 80 percent reaches the ground- water body. Response of ground-water levels to the annual flood cycle of the Columbia River in the 50—mile reach be- tween China Bar and Richland, Wash., provides a basis for evaluation of bank storage. R. C. Newcomb found GEOLOGICAL SURVEY RESEARCH lQfil—SYNOPSIS OF RESULTS that the ground-water rise, when evaluated with the effective porosity, placed in bank storage an average of 170,000 acre—feet of water during the river’s annual rise to flood peak. The stored water returns to the river during ebb flow in the succeeding 165 days. In studies of the Walla Walla River basin, Wash- ington and Oregon, R. C. Newcomb found that one- third of the 42 inches of annual precipitation on the mountainous watershed in the Blue Mountains infil— trates to the basalt and reaches the water table. The outflow to the South Fork and to Mill Creek provides the base flows of 150 cubic feet per second. These base flows are the main water supply of the basin during the dry summer months. Induced infiltration of surface water In a study of the hydrology of Wharton Tract, N.J., E. C. Rhodehamel and S. M. Lang have shown by means of water-level contours of pumping-test data that the connection between an underlying aquifer and the Mullica River is poor. An almost impervious layer of iron oxide in the stream bed is responsible. Effect of withdrawal of ground water on streamflow As part of studies of the geology and ground water of the Frenchman Creek basin above Palisade, Nebr., W. D. E. Cardwell and E. D. Jenkins made a long-range estimate of future irrigation withdrawals from wells and evaluated the effects on surface water. It was concluded that the point of effluence of Frenchman Creek would shift downstream about 5 miles and that the annual flow of Frenchman Creek into Enders reser- voir would be reduced by about 17,000 acre-feet. If the projected irrigation developments materialize, the combined flow of Stinking Water and Frenchman Creeks near Palisade would decrease from 98,000 acre- feet in 1952 to about 80,000 acre-feet in the year 2008. In a study of the Sevier Valley, Utah, between Sevier and Sigurd, R. A. Young and C. H. Carpenter deter- mined by water-budget methods that an observed de- crease of 20,000 acre-feet in streamflow is accompanied by additions to the ground-water level equivalent to a rise of one foot. This relation has been used to estimate the amount of ground water that may be pumped without seriously afl'ecting streamflow. Effect of impoundment on ground-water flow In 1958, the St. Lawrence River in the vicinity of Massena, N.Y., and Cornwall, Ontario, was impounded for the generation of electric power. The rise in river stage amounted to about 80 feet at the Moses-Saunders Power Dam and about 20 feet at Waddington, 25 miles upstream. Through a Wide area north of Massena the movement of ground water in the Beekmantown dolo- mite, the only extensive aquifer in the area, was GEOLOGY AND HYDROLOGY APPLIED TO PROBLEMS IN THE FIELD OF ENGINEERING reversed. Instead of flowing in a northerly direction toward the St. Lawrence it began to flow in a southerly direction toward the Grass River, which parallels the St. Lawrence at a distance of about 3 miles. Through- out most of the remainder of the area near the reservoir, ground—water levels were raised but the direction of ground—water flow was not reversed. Areas of artesian flow were developed in some low areas near the river. A network of drainage canals in the Fort Lauderdale area, Florida, serves also as a source of recharge of fresh water to the very permeable Biscayne aquifer. The recharge is very important in helping to maintain the position of the salt-water front. An electrical analog steady-state model of the area is being used by C. B. Sherwood to determine the most suitable water levels for the various canals during low water. Boundary conditions and trial potentials that simulate canal stage are imposed on the model; the resulting ground- water potentials are then mapped. The amount of fresh-water flow to the ocean is computed and the posi- tion of the salt-water front is estimated from the water- level map. LOW FLOWS Data processing by a high—speed digital computer has made practicable the determination of annual values of the lowest mean discharge of streams for periods of various lengths. Low-flow frequency curves, which are useful in project design, can thus be prepared quickly and easily. The Geological Survey has processed more than 50,000 station years of streamflow record and the work is con- tinuing. Products obtained thus far include (a) annual values of the lowest mean discharge for 11 periods ranging in length from 1 to 274 consecutive days, (b) annual values of the highest mean discharge for each of the 11 periods, and (c) values from which a duration curve for each station can be readily prepared. A low-flow frequency curve for each of the 11 periods at selected long-record stations in 10 eastern states is now available. These curves may be used to determine the dependable low-flow yield at the site, both without and with artificial storage. TIME OF TRAVEL OF WATER Industries along rivers create pollution problems and hazards. One hazard is the possibility of accidental release of dangerous contaminants upstream from points of withdrawal for water supply. Estimates of flow velocity and time of travel of contaminated water can be made from standard streamflow data. A study of the flow of water in the Potomac River recently completed by J. K. Searcy and L. C. Davis, J r., ( 1961) indicates a 50-percent chance that the travel time A—93 of water from Cumberland, Md., to Washington, D.C., is at least 110 hours in March and 345 hours in October. More specific estimates can be made by using the stage of the river on the day of the estimate. The estimate is based on velocities in cross-sectional areas at stream- gaging stations, and on correlation of concurrent dis— charge at upstream and downstream points. A companion study of the Ohio River by R. E. Steacy (1961) indicates that when the river discharge at Cin- cinnati is 60,000 cubic feet per second (the median daily discharge), travel time of water from Pittsburgh is 360 hours under average conditions. When the dis- charge is less than 30,000 cubic feet per second, as it generally is in August, September, and October, travel time is more than 600 hours. EVAPORATION SUPPRESSION In tests of methods for suppressing evaporation, R. R. Cmse and G. E. Harbeck, Jr. (1960) have examined 150 film-forming materials, all of which were found to be ineffectual at economic concentrations. A maximum reduction in evaporation of 18 percent was obtained with hexadecanol. ARTIFICIAL RECHARGE 0F AQUIFERS In many parts of the United States the prolonged withdrawal of ground water from wells has resulted in a lowering of the head and a decrease in the quan- tity of water available. Studies to determine the feasi- bility of artificially recharging underground reservoirs with surplus surface waters have been made in several selected areas by the Geological Survey. These studies have included recharge by spreading basins, by stream channel diversion and enlargement, and by injection wells. Spreading basins Recent studies by C. R. Groot (1960) near the well field of Newark, Del., show that when surface water is spread over the well field, infiltration takes place at a rate of 3 feet per day. This amount adds significantly to the ground-water reservoir. Stream channel diversion Tests by Morris Deutsch and J. E. Reed have shown that the aquifer supplying water to Kalamazoo, Mich., can be partly recharged with surface water by divert- ing a local stream and causing it to flow in a man-made channel across the well field. Yield deterioration in injection wells The performance of injection wells in basalt near Walla Walla, Wash, has been tested by R. H. Russell (1960), and the performance of wells in alluvium in A—94 the Grand Prairie region of Arkansas has been tested by R. T. Sniegocki, F. H. Bayley, III, and Kyle Engler. Partial clogging of the wells in both areas took place within 2 or 3 weeks. The clogging is believed to result from (a) sediment and dissolved air in the injected wa— ter, (b) precipitation of iron in the injected water as a result of aeration, and (c) micro-organisms in the in- j ected water. GEOLOGY AND HYDROLOGY 'APPLIED TO PROBLEMS IN THE FIELD OF PUBLIC HEALTH Urbanization and industrialization have caused in- creasing concern with problems of public health and safety. Many research studies of the Geological Sur— vey result in benefits in this field. Studies in 1961 di- rectly concerned with public health include work on the disposal of radioactive wastes, the distribution of elements in relation to health, and studies of coal-mine drainage in the eastern United States. STUDIES RELATED TO DISPOSAL OF RADIOACTIVE WASTES Studies bearing on radioactive waste storage or dis- posal are conducted on behalf of the Atomic Energy Commission and deal with actual and potential behav— ior of high-, intermediate—, and low-level wastes in specific geologic environments, and with the natural processes by which contaminants in surface and ground water are neutralized or dissipated. E. S. Simpson has shown that dispersion coefficients in natural streams are related to variables of stream flow that are relatively easy to measure. His studies bear directly on the mixing and dilution of radioactive and other wastes in streams. D. H. Hubbell is studying the extent to which radio- active material may be accumulated and concentrated in stream sediments. Tracer particles were released as an instantaneous line source in the stream channel of the North Loup River near Purdum, Nebr. The concentra- tion of particles in the stream bed were found to be a logarithmic function of the distance along the channel, and the standard deviation of the distribution increased in proportion to the time after release. The highest con- centration of particles moves downstream at a velocity about equal to the velocity of the dunes that represent the form of bed roughness. H. E. Skibitzke and others (19610) have studied the flow of water in a saturated porous aquifer through use of radioactive tracers. They have found that as the water and tracers move longitudinally through the aqui- fer, the rate of lateral spreading of the tracers is slightly less than the rate of spreading that would be produced by molecular diffusion in a motionless liquid. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Preliminary analyses of the Michigan Basin have been made by Wallace DeWitt, J r., and of the Appalachian Basin by G. W. Colton to determine the possibilities for radioactive-waste disposal. Colton concludes that in the Appalachian Basin, evaporites of the Salina group and sandstone, shale, and mudstone of the Bloomsburg red beds provide the safest natural reservoirs for storage, and that the Devonian black shales may be suitable for waste storage is artificially fractured reservoirs. DISTRIBUTION OF ELEMENTS AS RELATED TO HEALTH The increasing understanding of the importance of trace elements to the health and nutrition of both animals and humans has led to a desire for an appraisal of their mode of occurrence and degree of availability in soils of the United States. As a part of an environmental study being made on the occurrence of cancer, R. M. Moxham reports that the natural background radioactivity in Washington County, Md., varies according to a geologically con- trolled pattern, and that the more radioactive zones are associated with shale or with the shaly parts of lime- stone units. The amount of radiation is controlled largely by potassium, which is enriched in the residual clays. The surface radioactivity in Washington County varies by as much as a factor of 5, but more commonly by a factor of 2 to 3. The trace-metal composition of soils and plants has been studied by H. L. Cannon in two widely separated areas of abnormal cancer occurrence: glacial soils over- lying the Hamilton shale at Canandaigua, N. Y., and residual and alluvial soils on the Cambrian and Ordovician rocks in Washington County, Md. In both areas the content of total lead, copper, boron, and zinc in the soils is considerably above average, and that of manganese and iron is about normal. The. availability of most of these elements to plants is, on the other hand, very low. The content of copper, zinc, molyb— denum, and boron, and to an even greater degree, man- ganese and iron, are deficient in the garden vegetables as compared to the averages for herbs. Samples of vegetables collected within 25 feet of roads in Washington County, Md., contained an aver- age of 80 ppm (parts per million) lead in the ash, or about 4 times that of vegetables grown at distances of more than 500 feet from roads. In the Denver, Colo., area, pasture grass within 5 feet of major high- ways contains as much as 700 ppm lead in the ash, and grass at major intersections contains as much as 3,000 ppm in the ash. These data invite speculation on the possible toxic effects of this cumulative poison in GEOLOGY AND HYDROLOGY APPLIED T0 PROBLEMS OF PUBLIC HEALTH garden produce, particularly that grown near major highways. About 90,000 traverse miles have been flown during the past year by the Geological Survey as part of the nationwide program of aerial radiological monitoring surveys (ARMS) of the Atomic Energy Commission. These surveys provide essential data on environmental background radiation for evaluating the effects of radi- ation on health. The radioactivity data are also valu- able in supplementing geologic mapping in areas of heterogeneous rock types, thick residual soils, and low topographic relief. MINE DRAINAGE In connection with studies of drainage of anthracite mines in Pennsylvania, W. T. Stuart and T. A. Simp- son (Art. 37) noted that the pH of the water in certain flooded mines decreased with depth below the pool surface. In one mine the pH near the pool surface was 7.1 and near the bottom of the shaft it was 4.1. Where pool water was mixed by pumping, by overflow into drainage tunnels, or by some other cause, no sig- nificant layering of acid water was observed. Know].- edge of the distribution of the acid facilitates pollution control and may reduce the cost of pumping and handling. DEVELOPMENT OF EXPLORATION AND MAPPING TECHNIQUES In addition to conventional methods of exploration that depend primarily on mapping bedrock exposures and on examining samples from drill holes, much work is being done in the newer fields of geochemical and botanical exploration, and in the use of isotopes as clues to the distribution of mineral deposits. New equip- ment is being developed and old equipment modified to measure and record geologic and hydrologic data. GEOCHEMICAL AND BOTANICAL EXPLORATION F. C. Canney and A. L. Albee have discovered two major geochemical copper anomalies on Sally Moun- tain in the Attean quadrangle, Somerset County, Maine. This area also contains iron-stained, pyritized, and hydrothermally altered rock, and hence appears to have above average mineral-resource potential. In Aroostook County, Maine, anomalous amounts of molybdenum in soil samples may be used to locate molybdenum deposits beneath a thin cover of glacial drift. F. C. Canney, F. N. Ward, and M. J. Bright, J r., (Art. 117) report one anomaly in this area in which molybdenum occurs in concentrations 90 times the re- gional background. A495 Studies by L. ‘C. Hufl' and A. P. Marranzino (Art. 133) in the vicinity of alluvium-buried copper deposits in the Pima mining district of Arizona indicate that systematic analysis of ground water, phreatophytic plants, and carbonate-cemented zones at the base of the alluvium may yield data useful in searching for buried ore. Huff and Marranzino report anomalous amounts of molybdenum in ground water for at least 10 miles northeast (downslope) from the Pima and Mission ore bodies. Using the Geological Survey’s mobile spectrographic laboratory, R. L. Erickson and others (Art. 401) have discovered a geochemical anomaly in the upper plate of the Roberts Mountain thrust fault, Nevada, that may prove to be a leakage halo from concealed ore deposits in the thrust zone or in the carbonate rocks beneath the thrust. In the Red Mountain area of Clear Creek County, Colo., P. K. Theobald, J r., and C. E. Thompson (Art. 58) have found anomalous concentrations of several metals in large areas covered by poorly consolidated surface rubble. The patterns of the anomalies suggest early deposition of tungsten and molybdenum, accom- panied by removal of zinc and copper, and followed by deposition of lead and arsenic, and of minor amounts of zinc and copper. Botanical methods of prospecting for uranium on the Colorado Plateau have been described by Helen L. Cannon (1960b). Chemical differences in the rocks in mineralized areas produce recognizable changes in plant societies. Some plant species, therefore, are use- ful as indicators in prospecting. Other plants are use- ful in prospecting by plant analysis because they absorb increased amounts of uranium in uranium-rich areas. Chromatographic field tests have been devised to facilitate the rapid analysis of plant samples. R. W. Bayley and W. W. J anes (Art. 405) report on analysis of soils in the Atlantic gold district, Wy- oming, and suggest that anomalous concentrations of arsenic may indicate hidden quartz-arsenopyrite-gold veins. Conventional methods of prospecting are hindered by heavy vegetation and thick soil cover in the Coeur d’Alene district, Idaho. V. C. Kennedy (1960a) de- scribes soil-sampling techniques in this district and gives information on the dispersion of ore metals. Kennedy concludes that lead is the best indicator ele— ment in prospecting for ore bodies rich in lead and zmc. Botanical studies by H. T. Shacklette (1961) on Latouche Island, Alaska, have shown a close correla- tion of the metal content of the substrate with the A—96 composition of moss communities and with the succession of moss species. APPLICATION OF ISOTOPE GEOLOGY TO EXPLORATION The isotopic compositions of several elements are found to have large differences that can be related to origin and distribution of ores and rocks. Some of the more general applications, such as those in geochro— nology, are presented on pages A—80 to A—81 ; those that bear more directly on problems of ore deposits are discussed below. Isotope geology of lead A general review of the isotope geology of lead with particular reference to its application in the study of and search for ore deposits has been published by R. S. Cannon and others (1961). Further work by these men, in collaboration with S. W. Hobbs, V. C. Fryk- lund, and L. R. Stiefl', has shown that, in general, the leads in the major ore deposits of the northern Rockies region (Coeur d’Alene, Idaho, and East Kimberley, British Columbia) have similar isotopic compositions, whereas those in minor deposits have divergent com- positions. On a smaller scale, it is found that within the Coeur d’Alene district similar compositional dif- ferences exist between the larger and smaller ore bodies. In part, these differences may be related to stratigraphy of the Precambrian sedimentary rocks—the principal ore bodies of the Coeur d’Alene and East Kimberley districts are in the Prich-ard formation and its correla- tive, the Aldridge formation, whereas many of the minor deposits are in the calcareous Wallace formation and equivalents. Oxygen isotopes in mining districts of central United States The variations in isotopic composition of oxygen in the carbonate host rocks of the lead-zinc ore deposits of the Upper Mississippi Valley and of the fluorite deposits of Kentucky and Illinois are being investi- gated by W. E. Hall, Irving Friedman, and A. V. Heyl, Jr. At the Dyer Hill fluorite mine, Kentucky, the 013/016 ratio of the limestone (as determined by mass spectrometer and expressed in the standard permil units) changes within 40 feet from a normal limestone value of 24 0/00 to 16 0/00 as the ore is approached. The isotopic alteration of the wall rock by ore-forming solutions is in part dependent upon grain size; coarse- grained pre-ore calcite is less susceptible to change than is the finer grained limestone. The “falling drop” method of oxygen isotope analysis J. H. McCarthy, Sr., T. S. Lovering, and H. W. Lakin (Art. 292) have completed work on the “falling- drop” method for determination of oxygen isotope GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS ratios of carbonate rocks. The technique is designed to afford a rapid and inexpensive means of obtaining oxygen isotope data for geochemical exploration; dur- ing the year the apparatus and procedures have been simplified to allow operation by nontechnically trained personnel. RECORDING GEOLOGIC INFORMATION Magnifying single-prism stereoscope , A magnifying single-prism stereoscope designed by T. P. Thayer (Art. 426) for field use holds the photo- graphs firmly in place, provides magnifications up to 2 diameters, and covers the entire stereoscopic model. The stereoscope is 11/2 inches thick when folded, and weighs about 3 pounds. New method of recording geologic features E. H. Baltz and J. E. Weir, Jr., (Art. 137) have found that by constructing to scale a core diagram of large-diameter drill holes they can obtain quickly a true three-dimensional model of the rocks penetrated. The core diagrams can be used to determine strike and dip graphically or trigonometrically and to record graphically features observed on the walls of large- diameter drill holes. HYDROLOGIC MEASUREMENTS The scope of the Geological Survey’s hydrologic pro— gram is largely dependent upon the speed and accuracy of gathering data. As a result, measuring and record- ing devices are undergoing constant improvement. Several new instruments were put into use in 1961 as described below. Digital recorders and computer techniques A new technique for automatic recording and proc- essing basic streamflow data, developed by W. L. Isher- wood, makes use of a slow-speed battery-operated paper—tape punch at gaging stations and a general- purpose digital computer in Washington, DC. The field recorder samples a shaft-rotation input at intervals of 15, 30, or 60 minutes and punches each reading of river gage height as 4 binary—coded decimal digits in parallel mode on 16-channel paper tape. At the central processing center the 16-channel tape is translated to 7 —channel serial—coded paper tape suitable for computer entry so that the data can be edited by the computer and stored on magnetic tape. Stage-discharge rating tables needed for the computation of discharge are manually punched on paper tape. The computer produces 3 items of output as follows: (a) a printed form listing the daily mean gage heights, shift corrections, and daily ANALYTICAL CHEMISTRY mean discharges; (b) a set of IBM cards containing information on peak discharges to be listed off-line; (c) a set of IBM cards containing logarithmic plotting positions for use on an off -line automatic plotter. Recorders are installed on a trial basis at 260 of the Geological Survey’s nationwide network of more than 7,000 gaging stations. Velocity-measuring instruments Three new instruments for measuring water velocity in open channels are being developed. The acoustic velocity meter (H. 0. Wires, Art. 27) uses ultrasonic waves for the continuous recording of the mean in- tegrated velocity on a horizontal line within a stream cross section. The optical current meter (Winchell Smith, Art. 424) uses a system of rotating mirrors and a stroboscope to measure surface velocity. The electro- magnetic velocity meter, a modification of US. Navy’s ship log, continuously records‘ the velocity of water flowing past a fixed probe in the stream. Water mov— ing through the magnetic field set up by an exciter coil in the probe generates a voltage that is proportional to the water velocity. Stage-measuring instruments ‘ The surface follower, designed by G. F. Smoot, will follow the rise and fall of a liquid surface in a vertical 2-inch pipe. A battery-powered reversible motor raises or lowers a float-switch assembly in response to changes in elevation of the liquid surface. E. G. Barron and H. 0. Wires have designed a two- speed timer that automatically expands the time scale of a continuous water—stage recorder by a multiple of six during stages above a selected base. A solenoid— ratchet device advances the recorder paper 1/80 inch each time it receives an electrical impulse. Two sets of cams and contacts on the spring-driven clock provide either 8 or 48 pulses per hour. A selector switch can be set to change from the 8 pulse per hour contacts (2.4 inches per day) to the 48 pulse per hour contacts (14.4 inches per day) at the selected stage. Velocity-azimuth-depth assembly The velocity-azimuth-depth assembly, developed by E. G. Barron, H. 0. Wires, and G. F. Smoot, measures the velocity and direction of flow of water and the height above the bottom at any point in a stream. Velocity is measured with a Price current meter, direction of flow is given by a remote-indicating com- pass, and depth is measured by sonic means. The assembly is useful in investigations of tidal flows and of stream cross sections where the flow pattern may be complicated by variable eddy currents. A—97 Well logging Drill holes at the National Reactor Testing Station, Idaho, penetrate a sequence several hundred feet thick of interbedded basalt and elastic sedimentary rocks. P. H. Jones (Art. 420) finds that the diameter of the drill holes increases with the permeability of the rock, and that caliper logs are especially useful in identifying the aquifers and in determining their relative trans- missibility. ANALYTICAL AND OTHER LABORATORY TECHNIQUES The analytical laboratories of the Geological Survey contribute many different kinds of data necessary for the conduct of geologic and hydrologic investigations, and for this reason much analytical information has been summarized under other headings. In particular, analytical data applicable to studies of isotopes are sum- marized on pages A—80 to A—82 and A—96, and data applicable to geochemical prospecting are summarized on pages A—95 to A—96. In addition to providing factual data in support of other activities, the laboratories also independently in— vestigate new methods of analysis and new techniques that will improve accuracy and efliciency. Some of the results of these investigations are summarized below. ANALYTICAL CHEMISTRY Rapid rock analysis Rapid methods of analysis developed by Leonard Shapiro and W. W. Brannock 3’ for silicate rocks have been revised and supplemented with methods for car- bonate and phosphate rocks to form an integrated scheme for the complete analysis of the major rock types. Silicon, aluminum, total iron, titanium, phos- phorus, manganese, and fluorine are determined spectrophotometrically; calcium, magnesium, and iron titrimetrically; sodium and potassium by flame photo- metry; water and sulfur gravimetrically; and carbon dioxide volumetrically. Combined gravimetric and spectrographic analysis of silicates Extensive revision has been made by R. E. Stevens in the wet chemical procedures used in spectrogravimetric analysis. A photometric method has been adopted for determining silica passing into the filtrate in the deter— mination of silica. Small precipitates that have spread over the interior of a crucible cannot be collected readily for spectrographic analysis. Therefore, processes have been designed to keep such precipitates in the lump form obtained on ignition of a paper-filtered precipitate. For calcium and magnesium oxide separates, a simple 3" Shapiro, Leonard, and Brannock, W. W., 1956, Rapid analysis of silicate rocks: U.S. Geo]. Survey Bull. 1036—0. A—98 apparatus has been devised in which the oxides are converted to sulfates with sulfur trioxide vapors, thus avoiding solution and dispersal of material. Small quantities of alkalies, left at the end of the analysis, are collected by scrubbing the crucible with a wet filter paper-and igniting this below the melting point of the alkali sulfates. The alkalies are thus obtained as a lump, easily removed from the crucible. Spectrophotometry Mary H. Fletcher (1960a and b) has presented the results of her studies on the dye 2,2’,4’—trihydroxyazo- benzene-5-sulfonic acid and its reaction with zirconium. Published data include 3 of the 4 ionization constants of the dye, the two equilibrium constants for its reaction with zirconium, the absorption spectra of the various ionization forms of the dye, and the spectra of the zir- conium complexes. Methods are discussed for the interpretation of absorption spectra of multicomponent systems and for the determination of dye purity. Flame photometry Many elements interfere in flame photometric de- terminations by depressing the intensity of flame spectra. Preliminary results obtained by J. I. Dinnin (Art. 428) indicate that high concentrations of calcium, strontium, barium, or lanthanum completely release magnesium from the depressive effects of aluminum and phosphate in perchloric acid or acetone media. Stron- tium or calcium completely releases barium from the effects of aluminum and phosphate. Dinnin (Art. 429) describes a procedure for deter- mining strontium in which the depressive efl'ects of aluminum, phosphate, and sulfate are completely eliminated by high concentrations of lanthanum, praseodymium or neodymium. Two flame photometric methods for determining strontium in natural waters have been developed by C. A. Horr. Strontium can be determined directly in concentrations greater than 0.2 ppm when a potassium chloride-citrate radiation buffer is used. Strontium at concentrations as low as 0.02 ppm is determined by passing the sample through a strongly basic cation exchange resin and eluting with 2M ammonium acetate- 1‘M acetic acid solution, adjusted to a pH of 5.4. Stron- tium is concentrated 10-fold by this procedure, and is determined by flame photometry in the eluate. Errors due to anionic interference and variations in anionic composition of samples are thereby avoided. Sodium-sensitive glass electrodes Sodium-sensitive glass electrodes are useful in clay titrations, although their emf values cannot be indis- criminately used to yield sodium activities. A. M. Pommer (Art. 284) has found that in a montmorillonite GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS titration, the electrode gives low sodium activities at low sodium concentrations, possibly as a result of the formation of ion-pairs or NaCOa. Fatigue in scintillation counting A study of the variation of the counting rates of radium solutions by F. J. Flanagan (Art. 139) indicates that the photomultiplier fatigue causing the variations is due primarily to bremstrahlung produced by the interaction of beta particles with the glass containers. Silica in chromite and chrome ores J. I. Dinnin (Art. 433) found that in the gravimetric determination of silica in chromite enough silica re- mains unrecovered even after a double dehydration to cause appreciable error in the silica value for a purified chromite. As much as 2 milligrams of silica is unre- covered from a l-gram chromite sample containing 1 percent silica. Ferrous iron J. J. Fahey (Art. 291) has determined ferrous iron in samples of magnetite and ilmenite intergrown with amphiboles and pyroxenes by decomposing the oxide minerals with 1:1 hydrochloric acid and titrating the iron with permanganate. The decomposition proce- dure results in little or no solution of the ferrous iron silicates. R. L. Meyrowitz has developed a new microprocedure for determining ferrous iron in small amounts (5 to 15 mg) of pure refractory silicate minerals, such as garnets that contain a large proportion of both fer- rous iron and magnesium. The sample mixed with so- dium metafluoborate is fused in a Pregl platinum micro— boat at approximately 850° to 900°C in an argon atmos- phere. The melt is dissolved in a standard HzCrZO7 solution containing H280; and HF. The excess di- chromate is determined by titration with standard fer- rous iron using sodium diphenylamine sulfonate as the indicator. Indirect semiautomatic titration of alumina An indirect semiautomatic determination of alumina with EDTA was developed by J. I. Dinnin and C. A. Kinser (Art. 142). The method involves a back-titra— tion with ferric chloride of excess EDTA using tiron as an indicator. A sharp end point is obtained with a colorimetric recording titrator. Chemical test for distinguishing among chromite, ilmenite, and magnetite J. I. Dinnin and E. G. Williams (Art. 430) have described a test for distinguishing among chromite, ilmenite, and magnetite, based on the relative rates of dissolution of the minerals in a mixture of phosphoric and sulfuric acid and on the colors of the resultant acid solutions. SPECTROSCOPY Beryllium by gamma-ray activation Factors such as particle size, sample weight, and sample-container shape in the gamma-ray activation analysis method for beryllium were studied by Wayne Mountjoy and H. H. Lipp (Art. 287). Reliable re- sults are obtained when large samples are counted in half-pint cylindrical paper cartons. For samples under 100 g, counting is best done in conical holders. Par- ticle size has little effect on counts per gram of sample. Trace-element sensitivities F. S. Grimaldi and A. W. Helz (Art. 427) have compiled and evaluated trace-element sensitivities of wet chemical, spectrochemical, and activation methods of analysis. Precipitation of selenium A study of the completeness of precipitation of selenium with hydroxylamine was made by Irving May and, Frank Cuttitta (Art. 431). Precipitation was found to be 99.9 percent complete for concentrations of more than 0.9 parts per million (ppm) selenium, 99.0 percent complete for concentrations of 0.09 ppm selenium, and 80 to 90 percent complete for concentra- tions of 0.009 ppm selenium. Colorimetric iron determinations Bathophenanthroline in a N,N’—dimethylformamide medium was used by Frank Cuttitta and J. J. Warr (Art. 289) in the determination of traces of iron in zircon. Zirconium was complexed with mesotartaric acid to prevent its precipitation as the hydrous oxide. The reagent tiron was used by Leonard Shapiro and Martha S. Toulmin (Art. 141) for the colorimetric de- termination of iron in small samples of sphalerite. The method is simple and rapid and enables analyses to be made on individual crystal fragments as may be re- quired in geothermometry studies of sphalerites. Thallium in manganese ores The dithizone mixed-color method has been used by Frank Cuttitta (Art. 290) to determine small amounts of thallium in manganese ores. The interference of manganese, iron, bismuth, lead, tin, and indium was overcome by extracting thallium bromide with ethyl ether. Direct fluorescent procedure for beryllium A procedure was developed by Irving May and F. S. Grimaldi for the direct determination of beryllium in low-grade ores and in rocks using the well known fluorescent morin method. This very sensitive pro— cedure enables the determination of as little as 0.0002 percent beryllium in only a 0.5-mg aliquot of sample without the necessity of performing any separations. A—99 Copper in plant ash Neo—cuproine has been used for rapid determination of traces of copper in plant ash. Claude Huffman, J r., and D. L. Skinner (Art. 143) obtained a standard deviation of 9.6 ppm for the range of 15 to 200 ppm copper. SPECTROSCOPY Development and use of the electron microprobe and analyzer The electron microprobe analyzer,38 which provides point by point analysis of elements in absolute amounts as small as 10‘12 grams, has been modified to permit simultaneous determinations of 4 elements. Using the electron microprobe, Isidore Adler and E. J. Dwornik (Art. 112) analyzed shreibersite (rhab- dites), kamacite, and the associated oxides in a piece of the Canyon Diablo meteorite and found the nickel con- tent of 9 rhabdites ranges from 22 to 48 percent; the average of 11 determinations for nickel and iron in kamacite is 7.3 and 89 percent, respectively; and the oxide phase having the nickel content contains from 1.4 to 3.1 percent nickel and 46 to 48 percent iron. In another study, iron-titanium oxide minerals in grains from 5 to 10 microns in diameter were analyzed for iron and titanium for possible correlation with magnetic properties. It was possible to examine com- positional zoning from 2 to 4 microns across in a 40 micron grain. Spectrochemical analysis for beryllium with a direct-reading spectrograph Beryllium was determined in samples from Alaska, Colorado, and Utah by a spectrochemical method de- scribed by A. W. Helz and C. S. Annell (Art. 288) in which selected spectral lines are measured directly with multiplier phototubes rather than on a photographic plate. The samples were prepared by fusion in lithium tetraborate, powdered, mixed with graphite, and pressed into pellets one-half inch in diameter. The pellets were used as the lower electrode of a sparklike discharge for the production of the spectrum. Beryl- lium was determined in concentrations as low as 0.0002 percent even though the dilution of the sample with lithium tetraborate and graphite was 27 times. Spectrographic analysis of minor elements in natural water A method for the quantitative determination of 24 common minor elements in residues of evaporated water has been reported by Joseph Haifty (1960). Part of the water residue is mixed with one-half its 38 Synopsis of geologic results—Geological Survey research 1960: U.S. Geol. Survey Prof. Paper 440-A, p. A72—A73. A—lOO weight of pure graphite powder and the mixture com- pletely volatilized in a d—c arc of 16 amp. Concen- trations are determined directly from working curves prepared by arcing a series of standards containing known amounts of the elements in a matrix approxi- mating the composition of the water residues being analyzed. The analytical range for most minor ele- ments is 1.0 to 100 ,ug (micrograms) per liter. W. D. Silvey has applied chemical enrichment tech- niques to the determination of 17 minor elements in waters of widely different composition. Three organic chelating agents, 8-hydroxyquinoline, thionalide, and tannic acid, are added to a liter or more of sample. These agents quantitatively precipitate the minor ele- ments and separate them from the soluble major con- stituents. The ashed precipitate is mixed with pure graphite, the mixture transferred to cupped graphite electrodes, and excited in a d-c are. An excess of indium is added as a radiation buffer and palladium added as an internal standard. The method permits quantitative determination of 1.0 to 100 pg per liter of each of the 17 elements. For certain elements, as little as 0.1 ,ug per liter can be determined. A copper-spark procedure for determining the 5.0 to 1,000 pg per liter of strontium was developed by M. W. Skougstad. Measured volumes of a spectro- scopic buffer solution and a lanthanum chloride solu- tion (internal standard) are added to a 10-ml sample aliquot. One—tenth m1 portions of this sample mixture are then evaporated on the flat ends of copper electrodes and subjected to a high—voltage spark discharge. The measured relative intensities of the strontium lines at 4077 .7A and 4215.5A and the lanthanum lines at 3949.1A and 4077.3A are used to prepare working curves and for quantitative estimation of strontium concentrations. Spectrochemical analysis for major constituents in natural water with a direct-reading spectrograph Joseph Hafl'ty and A. W. Helz (Art. 144) investi- gated direct-reading techniques for determining four major constituents in water. Samples and standards, after being mixed with a reference solution, are excited directly using the rotating disk method. From 1 to 316 ppm of sodium, 3 to 316 ppm of calcium, 0.3 to 100 ppm of magnesium, and 3 to 31.6 ppm of silica can be determined in a single sample in a few minutes. MINERALOGIC AND PETROGRAPHIC TECHNIQUES Microscopy Determination of the optical properties of organic crystals with the universal stage is greatly handicapped by the strong birefringence and dispersion that charac- GEOLOGICAL SURVEY RESEARCH lQfil—SYNOPSIS OF RESULTS terize many organic compounds. R. E. Wilcox (1960) has pointed out that the difficulties are overcome with the spindle stage. Wilcox has also investigated the use of focal screening techniques in determining refractive indices of particles by the immersion method. These techniques take advantage of the generally strong dif- ference in dispersion in ordinary white light between the solid and a matching immersion liquid. The dis- persion produces color effects at the grain boundaries, depending upon the wave length at which the refractive indices of liquid and solid exactly match. Reliable de— terminations of refractive indices can be obtained by focal screening in many situations where the conven- tional Becke-line technique is difficult to apply, or fails altogether. X-ray petrography D. B. Tatlock (Art. 145) has shown that the relations among diffraction, adsorption, fluorescence, and rock density allow rapid and accurate quantitative measure- ments for total iron (FeO+Fe203) and quartz in most holocrystalline silicate rocks. Preliminary results show that K-feldspar, albite, muscovite, and andalusite may also be determined quantitatively in certain rock types. E. D. Jackson (Art. 252) has found that X-ray diffraction methods for determining the An content of plagioclase feldspars may be used confidently on feldspars from the same intrusive bodies. He points out that the plagioclases from a single intrusion will have similar thermal histories, therefore, there is no problem of X—ray parameter variance resulting from comparison of plagioclases with different thermal histories. X-ray methods A. J. Gude 3d, and J. C. Hathaway have devised a method for mounting very small (less than 1 mg) samples on the X-ray difl'ractometer. The sample is supported by extremely thin collodion membranes, which contribute insignificant amounts of background scatter to the X-ray pattern. The membranes are made by spreading thin films of colodion on water and transferring them to a standard diffractometer holder. The method takes advantage of the greater diffracto— meter speed and ease of interpreting the charts com- pared with the slower powder camera and film technique. E. C. T. Chao (1960a) has developed a viewing device that allows visualizing X-ray diffraction precession photographs in the third dimension. The three dimen- sional view of the reciprocal lattice simplifies the index- ing of reflections, and systematic extinctions of reflec- tions can be readily observed. MINERALOGIC AND PETROGRAPHIC TECHNIQUES Staining techniques W. R. Griflitts and L. E. Patten (Art. 286) have developed a method for determining the distribution of beryllium in rock specimens by partially dissolving the beryllium ore minerals on a cut slab and transferring the resulting pattern of dissolution to an activated filter paper. A morin solution on the filter paper is converted into a fluorescent beryllium—morin compound and the distribution of beryllium can be determined under ultraviolet light. Analyses using heavy liquids Robert Meyrowitz and others (1960) have extended their study of heavy liquid diluents and recommend that N, N -dimethyl formamide can be used as a diluent for methylene iodide. The N, N-dimethyl formamide- methylene iodide mixtures were found to be more color stable than the dimethyl sulfoxide—methylene iodide mixtures, though the latter are generally satisfactory. (See Cuttitta and others, 1960.) R. G. Coleman has used dimethyl sulfoxide as a diluent for both bromoform and methylene iodide to 608400 0—61—8 A—\101 prepare a density kit for field testing of rock chips. A series of stable liquids thus prepared covers a fairly broad density range and enables the geologist to esti- mate rock density on a semiquantitative basis in the field. Bulk density determinations C. M. Bunker and W. A. Bradley (Art. 134) have designed equipment for determining bulk density of drill-core samples by a nuclear irradiation technique involving gamma-ray absorption. Comparative data on a series of selected core samples show that the gamma-ray absorption method is much faster and has about the same accuracy as the standard laboratory methods for determining the bulk density of homo— geneous core samples. Sample preparation T. C. Nichols, J r., (Art. 140) describes a method of concentrating and preparing carbonate shells for C“ age determinations. Selective sieving, air elutriation, and cleaning with an ultrasonic transducer has sim- plified the separation of shell material and improved the quality of material for analysis. A—102 GEOLOGICAL SURVEY RESEARCH 1961—SYN'0PSIS 0F REISULTS U.S. GEOLOGICAL SURVEY OFFICES MAIN CENTERS US. Geological Survey, Main Oflice, General Services Building, 18th and F Streets, N.W., Washington 25, D.C., Republic 7—1820. US. Geological Srirvey, Rocky Mountain Center, Federal Center, Denver 25, Colorado, Belmont 3—3611. US. Geological Survey, Pacific Coast Center, 345 Middlefield Road, Menlo Park, California, Davenport 5—6761. GEOLOGIC DIVISION FIELD OFFICES IN THE UNITED STATES AND PUERTO RICO Location Alaska, College Arizona, Globe California, L0s Angeles Hawaii, Hawaii National Park Hawaii, Honolulu Kansas, Lawrence Kentucky, Lexington Maryland, Beltsville Massachusetts, Boston Michigan, Iron Mountain Mississippi, Jackson New Mexico, Albuquerque Ohio, Columbus Ohio, New Philadelphia Pennsylvania, Mt. Carmel Puerto Rico, Roosevelt Tennessee, Knoxville Utah, Salt Lake City Vermont, Montpelier Washington, Spokane Wisconsin, Madison Wyoming, Laramie [Temporary offices not included] Geologist in charge and telephone number Troy L. Péwé (3263) N. P. Peterson (964—W) John T. McGill (Granite 3—0971, ext. 9881) J. P. Eaton Charles G. Johnson Wm. D. Johnson, Jr. (Viking 3—2700) P. W. Richards (4—2473) Allen V. Heyl (Tower 9—6430, ext. 468) Lincoln R. Page (Kenmore 6—1444) K. L. Wier (1736) Paul L. Applin (Fleetwood 5—3223) Charles B. Read (Chapel 7—0311, ext. 483). J. M. SchOpf (Axminster 4—1810) James F. Pepper (4—2353) Thomas M. Kehn (339—4390) Watson H. Monroe (San Juan 6—5340) R. A. Laurence (2—7787) Lowell S. Hilpert (Empire 4—2552) W. M. Cady (Capitol 3—5311) A. E. Weissenborn (Temple 8—2084) C. E. Dutton (Alpine 5—3311, ext. 2128) W. R. Keefer (Franklin 5—4495) Address P.O. Box 4004; Brooks Memorial Building. P.0. Box 1211. Geology Building, University of California. Hawaiian Volcano Observatory. District Bldg. 96, Fort Armstrong. c/o State Geological Survey, Lindley Hall, University of Kansas. 915 S. Limestone Street. U.S. Geological Survey Building, Department of Agriculture Research Center. 270 Dartmouth Street, Room 1. P.O. Box 45. 1202}é North State Street. PO. Box 4083, Station A, Geology Building, University of New Mexico. Orton Hall, Ohio State University, 155 South Oval Drive. P.O. Box 272; Muskingum Watershed Con- servancy Building, 1319 Third Street, NW. P.0. Box 366; 56 West 2d Street. P.O. Box 803. 11 Post Office Building. 506 Federal Building. 7 Langdon Street. South 157 Howard Street. 213 Science Hall, University of Wisconsin. Geology Hall, University of Wyoming. SELECTED LIST OF WATER RESOURCES DIVISION FIELD OFFICES IN THE UNITED STATES AND Location Alabama, Montgomery Alabama, University Alaska, Anchorage Alaska, Juneau Alaska, Palmer Arizona, Phoenix Arizona, Tucson Arizona, Yuma Arkansas, Fort Smith Arkansas, Little Rock California, Sacramento Connecticut, Hartford Connecticut, Middletown PUERTO RICO [Temporary offices not included; list current as of March 15, 1961] Ofiicial in charge’ and telephone number Lamar E. Carroon (s), (263—7521, ext. 396 and 397) William J. Powell (g), (Plaza 2—8104) Roger M. Waller (g), (Broadway 2—8333) Ralph E. Marsh (s), (6—2815) Faulkner B. Walling (q), (Pioneer 5—3450) Herbert E. Skibitzke (g), (Alpine 8—5851, ext. 225) P. Eldon Dennis (g), and Douglas D. Lewis (s), (Main 3—7731, ext. 291 and 294) Charles C. McDonald (g), (Sunset 3—7841) John L. Saunders (s), (Sunset 3—6490) Richard T. Sniegocki (g), (Franklin 2—4361, ext. 270) Harry D. Wilson, Jr., (g), and Eugene Brown (q), (Ivanhoe 9—3661, ext. 322 and 381) John Horton (s), (Jackson 7—3281, ext 257) Robert V. Cushman (g), (Diamond 6—6986) Address P.O. Box 56; 507 New Post Office Building. P.O. Box V; Building 6, University of Alabama, Smith Woods. PO. Box 259; 501 Cordova Building, 555 Cordova Street. P.O. Box 2659; Room 111, Federal Building. PO. Box 36; Wright Building. Room 211, Ellis Building, 137 North 2d Avenue. P.O. Box 4126; Geology Building, University of Arizona. PO. Box 1488; 16 West 2d Street. PO. Box 149; Room 6, Post Office Building. 217 Main Street. 2929 Fulton Avenue. P.O. Box 715; 203 Federal Building. Post Office Building, Room 204. U.S. GEOLOGICAL SURVEY OFFICES A—103 SELECTED LIST OF WATER RESOURCES DIVISION FIELD OFFICES IN THE UNITED STATES AND Location Delaware, Newark Florida, Ocala Florida, Tallahassee Georgia, Atlanta Hawaii, Honolulu Idaho, Boise Illinois, Champaign Indiana, Indianapolis Iowa, Iowa City Kansas, Lawrence Kansas, Topeka Kentucky, Louisville Louisiana, Baton Rouge Maine, Augusta Maryland, Baltimore Maryland, College Park Massachusetts, Boston Michigan, Lansing Minnesota, St. Paul Mississippi, Jackson Missouri, Rolla Missouri, St. Louis Montana, Billings Montana, Helena Nebraska, Lincoln Nevada, Carson City New Mexico, Albuquerque PUER’I‘O RICO—Continued [Temporary oflices not included ; list current as of March 15, 1961] omcial in charge‘ and telephone number Donald R. Rima (g), (Endicott 8—1197) K. A. MacKichan (q), and Archibald 0. Patterson (s), (Marion 2—6513). Matthew I. Rorabaugh (g), (223—2636) Joseph T. Callahan (g), (Murray 8—5996) Albert N. Cameron (s), (Trinity 6—3311, ext. 5218) Dan A. Davis (g), (58—831, ext. 260 and 261) Howard S. Leak (s), (58—831, ext. 251) Wayne I. Travis (s), (4—4031), and Maurice J. Mundorff (g), (2—5441) William D. Mitchell (g), (Fleetwood 6—5221) Malcolm D. Hale (s), (Melrose 8—5541) Claude M. Roberts (g), (Melrose 2—1457) Vernal R. Bennion (s), (9345) Walter L. Steinhilber (g), (8—1173) Vinton C. Fishel (g), (2700, ext. 559) Elwood R. Leeson (s), (Central 3—0521) Gerth E. Hendrickson (g), and Floyd F. Schrader (s), (Juniper 4—1361, ext. 8235 and 8236) Fay N. Hanson (s), and Stanley F. Kapustka (q), (Dickens 3—6644) Rex R. Meyer (g), (Dickens 3—2873) Gordon S. Hayes (s), and Glenn C. Prescott (g), (Mayfair 3—4511, ext. 250) Edmond G. Otton (g), (Belmont 5—0771) John W. Odell (s), (Warfield 7—6348) 0. Milton Hackett (g), (Capitol 3—2725) Charles E. Knox (5), (Capitol 3-2726) Arlington D. Ash (s), (Ivanhoe 9—2431), and Morris Deutsch (g), (Ivanhoe 9—7913) Leon R. Sawyer (s), (Capitol 2—8011, ext. 265) Richmond F. Brown (g), (Capitol 2—8011, ext. 260) Joe W. Lang (g), (Fleetwood 5—2724), and William H. Robinson (s), (Fleetwood 2—2718) Harry C. Bolon (s), (Emerson 4—1599) James W. Geurin (q), (Main 1—8100, ext. 2161) Frank A. Swenson (g), (Alpine 9-2412) Frank Stermitz (s), (442—4890) Don M. Culbertson (q), (Hemlock 5—3273, ext. 346), Charles F. Keech (g), (Hemlock 5—3273, ext. 323), and Floyd F. Lefever (s), (Hemlock 5—3273, ext. 328) Leonard J. Snell (s), and Omar J. Loeltz (g), (Granite 2—1583) William E. Hale (g), (Chapel 7—0311, ext. 2248), and Jay M. Stow (q), (Chapel 7—0311, ext. 2249) Address . PO. Box 24; 92 East Main Street. P.O. Box 607; Building 211, Roosevelt Village. Post Office Drawer 110, Gunter Building. 19 Hunter Street, S.W., Room 416. 805 Peachtree Street, Room 609. Room 332, Home Insurance Building, 1100 Ward Avenue. Room 330, Home. Insurance Building, 1100 Ward Avenue. 914 Jefferson Street, Room 215. 605 South Neil Street. 611 North Park Avenue, Room 407. 611 North Park Avenue, Room 403. 508 Hydraulic Laboratory. Geology Annex- State University of Iowa. c/o University of Kansas. P.O. Box 856; 403 Federal Building. 522 West Jefferson Street, Room 310. Room 300, Leach Building, 315 Main Street. P.O. Box 8516, University Station; Room 43, Atkinson Hall, Louisiana State University. 422 State House. 103 Latrobe Hall, The Johns Hopkins Uni- versity. P.O. Box 37; 106 Engineering Classroom Building, University of Maryland. Room 847, Oliver Building, 141 Milk St. Room 845, Oliver Building, 141 Milk St. 407 Capitol Savings and Loan Building. 1610 Post Office Building. 1002 Post Oflice Building. PO. Box 2052; 402 High Street. PO. Box 138; 900 Pine Street. Room 728, US. Court House and Customs House, 1114 Market Street. PO. Box 1818; Room 201, 202, 212; North 7th Street West. P.O. Box 1696; 409 Federal Building. Room 132, Nebraska Hall, 901 North 17th Street. PO. Box B; 809 North Plaza Street. Box 4217, Geology Building, University of New Mexico. A—104 GEOLOGICAL SURVEY RESEARCH 1961—SYN'OPSIS OF REISULTS SELECTED LIST OF WATER RESOURCES DIVISION FIELD OFFICES IN THE UNITED STATES AND Location New Mexico, Sante Fe New York, Albany North Carolina, Raleigh North Dakota, Bismarck North Dakota, Grand Forks Ohio, Columbus Oklahoma, Norman Oklahoma, Oklahoma City Oregon, Portland Pennsylvania, Harrisburg Pennsylvania, Philadelphia Puerto Rico, San Juan Rhode Island, Providence South Carolina, Columbia South Dakota, Huron South Dakota, Pierre Tennessee, Chattanooga Tennessee, Memphis Tennessee, Nashville Texas, Austin Utah, Salt Lake City Virginia, Charlottesville Washington, Tacoma West Virginia, Charleston West Virginia, Morgantown Wisconsin Madison 7 Wyoming, Casper Wyoming, Cheyenne Wyoming, Worland PUERTO RICO—Continued [Temporary offices not included; list current as of March 15, 1961] Oflicial in charge“ and telephone number Wilbur L. Heckler (s), (Yucca 2—1921) Ralph C. Heath (g), (Hobart 3—5581) Donald F. Dougherty (s), (Hobart 3—5581) Felix H. Pauszek (q), (Hobart 3—5581) Granville A. Billingsley (q); Philip M. Brown (g); and Edward B. Rice (s), (Temple 4—6427) Harlan M. Erskine (s), (Capitol 3—3525) ‘ Edward Bradley (g), (4—7221) Lawrence C. Crawford (5), (Axminster 1— 1602) George W. Whetstone (q), (Belmont 1—7553) Stanley E. Norris (g), (Capitol 1—6411, ext. 281) Alvin R. Leonard (g), (Jefferson 6—1818) Richard P. Orth (q), (Orange 7—5022) Alexander A. Fishback, Jr. (5), (Central 6— 5601, ext. 377 and 277) Kenneth N. Phillips (s), (Belmont 4-3361, ext. 239), Bruce L. Foxworthy (g), (Bel- mont 4—3361, ext. 236), and Leslie B. Laird (q), (Belmont 4—3361, ext. 241) Joseph E. Barclay (g), (Cedar 8—4925) John J. Molloy (s), (Cedar 8-5151, ext. 2724) Norman H. Beamer (q), (Market 7-6000, ext. 274 and 275) Dean B. Bogart (s), (3—3989) William B.‘Allen (g), (Dexter 1—9312) Albert E. Johnson (s), (Alpine 2—2449) George E. Siple (g), (Alpine 3—7478) John E. Powell (g), (Elgyn 2—3756) John E. Wagar (s), (Capital 4—7856) Joseph s. Cragwall, Jr. (s), (Amherst 6—2725) Elliot M. Cushing (g), (Fairfax 3—4841) Joe L. Poole (g), (Cypress 8—2849) Leon S. Hughes (q), Allen G. Winslow (g), and Trigg Twichell (s), (Greenwood 6—6981) John G. Connor (q), (Davis 2—3711) Harry D. Goode (g), (Empire 4—2552, ext. 434) Milton T. Wilson (s), (Empire 4—2552, ext. 436) James W. Gambrell (s), (3—2127) Wilbur D. Simons (h), (Market 7—2678) Arthur A. Garrett (g), (Greenfield 4—4261) Fred M. Veatch (s), (Fulton 3—1491) Warwick L. Doll (s), (Dickens 4—1631, ext. 37) Gerald Meyer (g), (Linden 2—8103) Charles R. Holt, Jr. (g), (Alpine 5—3311, ext. 2329). Kenneth B. Young (s), (Alpine 6—4411, ext. 494). George L. Haynes, Jr. (s), (2—6339) Ellis D. Gordon (g), (634—2731, ext. 37) Thomas F. Hanley (q), (Fireside 7—2181) Address PO. Box 277; Room 224, Federal Courthouse. PO. Box 229; 342 Federal Building. P.O. Box 948; 343 Federal Building. PO. Box 68; 348 Federal Building. P.O. Box 2857; 4th Floor, Federal Building. PO. Box 750; Room 7, 202% 3d Street. Box LL, University Station. 1509 Hess Street. 2822 East Main Street. Room 554, U.S. Post Office Building, 85 Marconi Boulevard. PO. Box 780; Building 901, University of Oklahoma North Campus. PO. Box 4355; 2800 South Eastern. Room 402, 1101 North Broadway. P.O. Box 3418; Interior Building, 1001 North— east Lloyd Boulevard. 100 North Cameron Street. PO. Box 421; 490 Educational Building. 2d and Chestnut Streets, Room 1302, U.S. Custom House. 1209 Avenida Fernandez, Juncos Santurce. Room 401, Post Office Annex. 1247 Sumter Street, 210 Creason Building. Box 5314; 2215 Devine Street. PO. Box 1412; 231 Federal Building. PO. Box 216; 207 Federal Building. 823 Edney Building. Memphis General Depot, U.S. Army. 90 White Bridge Road. Vaughn Building, 807 Brazos Street. PO. Box 2657; Building 504, Fort Douglas. 503—A Federal Building. 463 Federal Building PO. Box 3327, University Station; Natural Resources Building, McCormick Road. 529 Perkins Building. 3020 South 38th Street. 207 Federal Building. Room 111, U.S. Courthouse. 405 Mineral Industries Building, West Virginia University. 175 Science Hall, University of Wisconsin. 699 State Office Building. P.O. Box 442; 150 South Jackson. Room 03—B, 2002 Capitol Avenue. 1214 Big Horn Avenue. ‘The small letter in parentheses following each oflicial’s name signifies his branch affiliation in Water Resources Division as follows: g—Ground Water Branch; q—Quality of Water Branch; s—Surface Water Branch; h—General Hydrology Branch. U.S. GEOLOGICAL SURVEY OFFICES A_105 GEOLOGICAL SURVEY OFFICES IN OTHER COUNTRIES Location Bolivia, La Paz Brazil, Belo Horizonte Brazil, Porto Alegre Brazil, Rio de Janeiro Brazil, Sao Paulo Chile, Santiago Germany, Heidelburg Indonesia, Bandung Libya, Tripoli Mexico, México, D.F. Pakistan, Quetta Philippines, Manila Taiwan, Taipei (Formosa) Thailand, Bangkok Turkey, Istanbul Location, Afghanistan, Lashkar Gah Chile, Santiago Iran, Teheran Libya, Benghazi Pakistan, Lahore Philippines, Manila Tunisia, Tunis Turkey, Ankara United Arab Republic (Egypt), Cairo GEOLOGIC DIVISION Geologist in charge Mailing Address Charles M. Tschanz U.S. Geological Survey, USOM/LaPaz, c/o American Embassy, La Paz, Bolivia. J. V. N. Dorr, II U.S. Geological Survey, Caixa Postal 107, Belo Horizonte, Minas Gerais, Brazil. A. J. Bodenlos U.S. Geological Survey, c/o American Consulate General— P.A., APO 676, New York, New York. A. J. Bodenlos U.S. Geological Survey, USOM, American Embassy, APO 676, New York, New York A. J. Bodenlos U.S. Geological Survey, 0/0 American Consulate General— S.P., APO 676, New York, New York. W. D. Carter U.S. Geological Survey, 0/0 American Embassy, Santiago, Chile. R. H. Bernard U.S. Geological Survey Team (Europe), 139 Engineer Detachment (Terrain), APO 403, New York, New York. Robert Johnson U.S. Geological Survey, USOM to Indonesia, c/o American Embassy, Djakarta, Indonesia. Gus Goudarzi U.S. Geological Survey, USOM, APO 231, c/o Postmaster, New York, New York. Ralph Miller U.S. Geological Survey, USOM, American Embassy, Mexico, D.F., Mexico. J0hn A. Reinemund U.S. Geological Survey, USOM, American Embassy, APO 271, New York, New York. Joseph F. Harrington U.S. Geological Survey, 0/0 American Embassy, APO 928, San Francisco, California. Samuel Rosenblum U.S. Geological Survey, ICA/MSM/China, APO 63, San Francisco, California. Louis S. Gardner U.S. Geological Survey, 0/0 American Embassy, APO 146, Box B, San Francisco, California. Quentin D. Singewald U.S. Geological Survey/ICA, 0/0 American Embassy, APO 380, New York, New York. WATER RESOURCES DIVISION [List current as of March 15, 1961] Official in charge Mailing Address R. H. Brigham U.S. Geological Survey, USOM-Kabul/Lashkar Gah, De- partment of State Mail Room, Washington 25, D.C. R. J. Dingman U.S. Geological Survey, c/o American Embassy, Santiago, Chile. A. F. Pendleton U.S. Geological Survey, USOM-Agriculture Division, APO 205, New York, New York. J. R. Jones U.S. Geological Survey, USOM, APO 231 (Box B), 0/0 ‘ Postmaster, New York, New York. D. W. Greenman U.S. Geological Survey, USOM, American Embassy, APO 271, New York, New York. C.‘R. Murray U.S. Geological Survey, USOM/ICA (Manila, P.I.), APO 928, San Francisco, California. H. E. Thomas - U.S. Geological Survey, USOM to Tunisia, 0/0 American Embassy, Department of State Mail Room, Washington 25, D.C. C. C. Yonker U.S. Geological Survey, c/o ICA, APO 254, New York, New York. H. A. Waite U.S. Geological Survey, USOM/Cairo, Department of State Mail Room, Washington 25, DC. A—106 GEOLOGICAL SURVEY RESEARCH 196l—SYNOPSIS OF RESULTS COOPERATING AGENCIES FEDERAL AGENCIES Agricultural Research Service Department of Defense Air Force Advanced Research Projects Agency Cambridge Research Center Department of Justice Technical Application Center Department Of State - Army Federal Housing Administration Corps of Engineers Federal Power Commission Forest Service International Cooperation Administration Maritime Administration National Park Service Navy Bureau of Yards and Docks Office of Naval Research National Aeronautical and Space Administration National Science Foundation Oflice of Minerals Exploration Public Health Service Soil Conservation Service Tennessee Valley Authority Atomic Energy Commission Division of Biology and Medicine Division of Reactor Development Military Application Division Office of Isotope Development Raw Materials Division Research Division Special Projects Division Bonneville Power Administration Bureau of Indian Affairs Bureau of Land Management Bureau of Mines Bureau Of PUblic Roads US. Study Commission—Southeast River Basins Bureau of Reclamation US Study Commission—Texas Bureau of Sport Fisheries and Wildlife Veterans Administration Coast Guard Weather Bureau STATE, COUNTY, AND MUNICIPAL AGENCIES Alabama : California : Geological Survey of Alabama California Department of Natural Resources, Division of Alabama Highway Department Mines Department of Conservation State Department of Water Resources Water Improvement Commission Alameda County Water District Calhoun County Board of Revenue Calaveras County Water District Morgan County Board of Revenue and Control Contra Costa County Flood Control and Water Conserva- Tuscaloosa County Board of Revenue tion District City of Athens County of Los Angeles, Department of County Engineers City of Huntsville Montecito County Water District City of Russellville Water Board Monterey County Flood Control and Water Conservation Alaska : District Alaska Department of Natural Resources North Marin County Water District Alaska Department of Health Orange County Flood Control District Arizona: Santa Barbara County Water Agency State Land Department Santa Clara County Flood Control and Water Conserva- Regents of the University of Arizona tion District Superior Court, County of Apache, Arizona Santa Cruz County Flood Control and Water Conservation Maricopa County Flood Control District District Maricopa County Municipal Water Conservation District City of Arcata No. 1 San Francisco Water Department City of Flagstaff San Luis Obispo Flood Control and Water Conservation City of Tucson District Navajo Tribal Council Santa Barbara Water Department Buckeye Irrigation Company East Bay Municipal Utility District Gila Valley Irrigation District Georgetown Divide Public Utility District Salt River Valley Water Users Association Hetch Hetchy Water Supply San Carlos Irrigation and Drainage District Imperial Irrigation District Arkansas: Metropolitan Water District of Southern California Arkansas Geological and Conservation Commission Palo Verde Irrigation District Arkansas State Highway Commission San Bernardino Valley Water Conservation District University of Arkansas—Agricultural Experiment Station Santa Maria Valley Water Conservation District University of Arkansas—Engineering Experiment Station Ventura River Municipal Water District COOPERATING AGENCIES A—107 STATE, COUNTY, AND MUNICIPAL AGENCIES—Continued Colorado: Oflice of State Engineer, Division of Water Resources Colorado State Metal Mining Fund Board Colorado Water Conservation Board Colorado Agricultural Experiment Station Board of County Commissioners, Boulder County Colorado Springs—Department of Public Utilities Denver Board of Water Commissioners Arkansas River Compact Administration Colorado River Water Conservation District Rio Grande Compact Commission Southeastern Colorado Water Conservancy District Connecticut : Connecticut Geological and Natural History Survey State Water Resources Commission Greater Hartford Flood Commission Hartford Department of Public Works New Britain Board of Water Commissioners Engineering Department——City of Torrington Delaware: Delaware Geological Survey State Highway Department Chester County Soil Conservation District City of Newark District of Columbia: District of. Columbia Department of Sanitary Engineering Florida: Florida Geological Survey State Board of Parks and Historic Memorials State Road Department of Florida Collier County—Board of County Commissioners Dade County~—Board of County Commissioners Hillsborough County—Board of County Commissioners Orange County—Board of County Commissioners Pinellas County—Board of County Commissioners Polk County—Board of County Commissioners City of Fort Lauderdale City of Jacksonville, Oflice of the City Engineer City of Miami—Department of Water and Sewerage City of Miami Beach City of Naples City of Pensacola City of Perry City of Pompano Beach City of Tallahassee Central and Southern Florida Flood Control District Trustees of Internal Improvement Fund Georgia: State Division of Conservation Department of Mines, Mining and Geology State Highway Department Hawaii : Commission of Public Lands, Hawaii State Department of Land and Natural Resources Idaho: Idaho Department of Highways Idaho Department of Reclamation Idaho State Fish and Game Commission Illinois: State Department of Public Works and Buildings—Division of Highways State Department of Public Works and Buildings—Division of Waterways State Department of Registration and Education Cook County Department of Highways Fountain Head Drainage District Indiana: State Department of Conservation—Division of Water Resources State Highway Commission Iowa: Iowa Geological Survey Iowa State Conservation Commission Iowa Natural Resources Council Iowa State Highway Commission Iowa Institute of Hydraulic Research Iowa State College—Agricultural Experiment Station Board of Supervisors, Linn County City of Fort Dodge—Department of Utilities Kansas: State Geological Survey of Kansas, University of Kansas State Board of Agriculture, Division of Water Resources State Highway Commission State Water Resources Board City of Wichita, Water Supply and Sewage Treatment Division Kentucky: Kentucky Geological Survey, University of Kentucky Louisiana: State Geological Survey State Department of Conservation State Department of Highways State Department of Public Works Maine: Maine Public Utilities Commission Maryland: State Department of Geology, Mines, and Water Resources Maryland National Capital Park and Planning Commission Anne Arundel County Planning Commission Commissioners of Charles County City of Baltimore Massachusetts : State Department of Public Works Massachusetts Department of Public Health Massachusetts Water Resources Commission Boston Metropolitan District Commission Michigan: Department of Conservation, Geological Survey Division State Water Resource Commission Minnesota : State Department of Conservation, Division of Waters State of Minnesota Department of Highways Board of County Commissioners of Hennepin County Department of Iron Range Resources and Rehabilitation A—108 GEOLOGICAL SURVEY RESEARCH 196l—SYNOPSIS OF REISULTS STATE, COUNTY, AND MUNICIPAL AGENCIES—Continued Mississippi : Mississippi Board of Water Commissioners Mississippi State Highway Department Jackson County, Mississippi, Port Authority City of Jackson Mississippi Industrial and Technological Research Com- mission Missouri: Division of Geological Survey and Water Resources Missouri State Highway Commission Curators of the University of Missouri Montana : Montana Bureau of Mines and Geology State Engineer State Fish and Game Commission State Highway Commission State Water Conservation Board Nebraska: Department of Water Resources Department of Roads University of Nebraska—Conservation and Survey Division Nebraska Mid-State Reclamation District Sanitary District Number One of Lancaster County Nevada: Nevada Bureau of Mines, University of Nevada Department of Conservation and Natural Resources New Hampshire: New Hampshire Water Resources Board New Jersey 2 State Department of Conservation and Economic Develop- ment Rutgers University, the State University of New Jersey North Jersey District Water Supply Commission Passaic Valley Water Commission New Mexico : State Bureau of Mines and Mineral Resources State Engineer State Highway Department New Mexico Institute of Mining and Technology Board of Hudson River-Black River Regulating District Interstate Stream Commission Pecos River Commission Rio Grande Compact Commission New York: State Conservation Department State Department of Health State Department of Public Works County of Dutchess—Dutchess County Board of Supervisors County of Nassau—Department of Public Works Onondaga County Public Works Commission Onondaga County Water Authority Rockland County Board of Supervisors Suffolk County Board of Supervisors County of Sufi’olk—Suffolk County Water Authority County of Westchester—Department of Public Works City of Albany—Department of Water and Water Supply City of Auburn—Water Department City of J amestown—Board of Public Utilities New York City Board of Water Supply New York—C ontinued New York City Department of Water Supply; Gas and Electricity Village of Nyack—Board of Water Commissioners Schenectady Water Department Brighton Sewer District #2 Oswegatchie-Cranberry Reservoir Commission North Carolina : North Carolina Department of Conservation and Develop- ment State Department of Water Resources State Highway Commission Martin County——Board of County Commissioners City of Asheville City of Burlington City of Greensboro City of Waynesville North Dakota : North Dakota Geological Survey State Highway Department State Water Conservation Commission Ohio: Ohio Department of Natural Resources—Division of Water Hamilton County, Board of County Commissioners City of Columbus—Department of Public Service Miami Conservancy District Ohio River Valley Water Sanitation Commission Oklahoma : Oklahoma Geological Survey Oklahoma State Department of Health Oklahoma Water Resources Board Oklahoma City Water Department Oregon: Oregon Agricultural Experiment Station State Highway Department Oregon Fish Commission Oregon State College—Department of Fish and Game Management Oregon State Sanitary Authority County Court of Douglas County County Court of Morrow County City of Dallas City of Dalles City City of Eugene—Water and Electric Board City of McMinnville—Water and Light Department City of Portland City of Toledo Coos Bay North Bend Water Board Pennsylvania : Bureau of Topographic and Geologic Survey, Department of Internal Affairs State Department of Agriculture State Department of Forests and Waters City of Bethlehem City of Harrisburg City of Philadelphia Rhode Island : State of Rhode Island and Providence Plantations Rhode Island Water Resources Coordinating Board State Department of Public Works—Division of Harbors and Rivers COOPERATING AGENCIES A—109 STATE, COUNTY, AND MUNICIPAL AGENCIES—Continued South Carolina : State Development Board State Highway Department State Public Service Authority State Water Pollution Control Authority City of Spartanburg—Public Works Department South Dakota : State Industrial Development Expansion Agency South Dakota Department of Highways South Dakota Water Resources Commission Tennessee: Tennessee Department of Conservation and Commerce—— Division of Geology Tennessee Department of Conservation and Commerce— Division of Water Resources Tennessee Game and Fish Commission Tennessee Department of Highways Tennessee Department of Public Health—Stream Pollution Control City of Chattanooga Memphis Board of Light, Gas, and Water Commissioners, Water Division Texas: State Board of Water Engineers Texas Department of Agriculture Texas A & M Research Foundation Pecos River Commission Rio Grande Compact Commission Sabine River Compact Administration Utah: Utah State Engineer Utah Water and Power Board State Road Commission of Utah University of Utah Salt Lake County Bear River Compact Commission Vermont: State Water Conservation Board Virginia: Department of Highways County of Chesterfield County of Fairfax City of Alexandria City of Charlottesville Virginia—Continued City of Newport News—Department of Public Utilities City of N orfolk—Division of Water Supply City of Roanoke City of Staunton Washington: State Department of Conservation, Division of Mines and Geology State Department of Conservation, Division of Water Resources State Department of Fisheries State Department of Game State Department of Highways State Pollution Control Commission Municipality of Metropolitan Seattle Seattle Light Department Seattle Water Department City of Tacoma \ West Virginia: State Geological and Economic Survey State Water Resources Commission Clarksburg Water Board Ohio River Valley Water Sanitation Commission Wisconsin: Wisconsin Geological and Natural History Survey, Uni- versity of Wisconsin State Highway Commission Public Service Commission of Wisconsin State Committee on Water Pollution Madison Metropolitan Sewerage District Wyoming: Geological Survey of Wyoming State Engineer’s Oflice Wyoming Highway Department Wyoming Natural Resource Board City of Cheyenne—Board of Public Utilities Commonwealth : Puerto Rico: Puerto Rico Water Resources Authority Unincorporated Territories: American Samoa : Government of American Samoa Guam: ' Government of Guam A—110 GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS INVESTIGATIONS IN PROGRESS IN THE GEOLOGIC AND WATER RESOURCES DIVISIONS DURING THE FISCAL YEAR 1961 Investigations in progress in the Geologic and Water Resources Divisions during the fiscal year 1961 are listed below, together with the names and headquarters of the individuals in charge of each. The list includes some projects that have been completed except for pub— lication of final results, and a few that have been temporarily recessed. Headquarters for major offices are indicated by the initials (W) for Washington, D.C., (D) Denver, 0010., and (M) for Menlo Park, Calif. Headquarters in other cities are indicated by name; see list of oflices on preceding pages for addresses. For projects in the Water Resources Division, a lower case letter before the city initial or name indicates the unit under which the project is administered, g, Branch of Ground Water; 5, Branch of Surface Water; q, Branch of Quality of Water; h, Branch of General Hydrology; and w, Water Resources Division. Projects that include a significant amount of geologic mapping are indicated by asterisks. One asterisk (*) indicates mapping at a scale of a mile to the inch or larger, and two asterisks (**) indicate mapping at a scale smaller than a mile to the inch. The projects are classified by State or similar unit and are repeated as necessary to show work in more than one State. However, projects that deal with areas larger than 4 States are listed only under the heading, “Large Regions of the United States”. Topical investigations, such as commodity studies, studies of geologic and hydrologic processes and meth- ods, are listed under the single most appropriate topical heading, even though the work may deal with more than one subject. Topical investigations that involve specific areas are also listed under regional headings. REGIONAL INVESTIGATIONS Large regions of the United States: Geologic map of the United States P. B. King (M) Gravity map of the United States H. R. Joesting (W) Coal fields of the United States J. Trumbull (W) Paleotectonic maps of the late Paleozoic E. D. McKee (D) Synthesis of geologic data on Atlantic Coastal Plain and Continental Shelf J. E. Johnston (W) Aeromagnetic profiles over the Atlantic Continental Shelf and Slope E. R. King (W) Cross-country aeromagnetic profiles E. R. King (W) Aerial radiological United States P. Popenoe (W) Geology of the Piedmont region of the Southeastern States (monazite) W. C. Overstreet (W) Igneous rocks of Southeastern United States 0. Milton (W) Geophysical studies of Appalachian structure E. R. King (W) Geology of the Appalachian Basin with reference to dis- posal of high-level radioactive wastes G. W. Colton (W) Lower Paleozoic stratigraphic paleontology, Eastern United States R. B. Neuman (W) Ordovician stratigraphic paleontology 0f the Great Basin and Rocky Mountains R. J. Ross, Jr. (D) monitoring surveys, Northeastern Large regions of the United States—Continued Silurian and Devonian stratigraphic paleontology of the Great Basin and Pacific Coast C. W. Merriam (W) Upper Paleozoic stratigraphic paleontology, Western United States J. T. Dutro, Jr. (W) Mesozoic stratigraphic paleontology, coasts N. F. Sohl (W) Mesozoic stratigraphic paleontology, Pacific coast D. L. Jones (M) Cordilleran Triassic faunas and stratigraphy N. J. Silberling (M) Jurassic stratigraphic palenontology of North America R. W. Imlay (W) Cretaceous stratigraphy and paleontology, western interior United States W. A. Cobban (D) Cenozoic mollusks, Atlantic and Gulf Coastal plains D. Wilson (W) Middle and Late Tertiary history of parts of the Northern Rocky Mountains and Great Plains N. M. Denson (D) Summary of the ground- -water situation in the United States C. L. McGuinness (g, W) Water use in the United States, 1960 K. A. MacKichan (h, W) Long term Nation wide chronologies of hydrologic events W. D. Simons (h, Tacoma, Wash.) Collection of basic records on chemical quality and sediment of surface waters of the United States S. K. Love (q, W) Fluvial denudation in the United Sates. Phase 2,—Vari- ance in water quality and environment F. H. Rainwater (q, W) Atlantic and Gulf REGIONAL INVESTIGATIONS IN PROGRESS Large regions of the United States—Continued Chemical characteristics of larger public water supplies in the United States C. N. Durfor (q, W) Spatial distribution of chemical constituents in ground water, Eastern United States W. Back (g,W) Geology and ground—water hydrology of the Atlantic and Gulf Coastal Plains as related to disposal of radio- active wastes H. E. LeGrand (w, W) Fluvial sediments and solutes in the Potomac River basin J. W. Wark (q, Rockville, Md.) Geology and hydrology of the Central and Northeastern States as related to the management of radioactive materials W. C. Rasmussen (g, Newark, Del.) Some discharge relationships of the Red River of the South G. H. Dury (W, W) Mississippi Embayment hydrology E. M. Cushing (g, Memphis, Tenn.) Problems of contrasting ground water media in consoli- dated rocks in humid areas, Southeastern United States H. E. LeGrand (w, W) Geology and hydrology of Great Plains States as related to the management of radioactive materials W. C. Rasmussen (g, Newark, Del.) Geology and hydrology of the western states as related to the management of radioactive materials R. W. Maclay (g, St. Paul, Minn.) Appraisal of water resources of Upper Colorado River basin, Colorado, Wyoming, Utah, New Mexico, and Arizona W. V. Iorns (q, Salt Lake City, Utah) Snake River Basin—quality of surface waters L. B. Laird (q, Portland, Oreg.) Effect of mechanical treatment on arid land in the Western United States F. A. Branson, (h, D) Hydrology of the public domain H. V. Peterson (h, M) Water-supply exploration on the public domain (Western States) G. G. Parker (h, D) Hydrologic atlas of Pacific Northwest W. D. Simons (h, Tacoma, Wash.) Water resources of entire states K. A. MacKichan (h, W) Alabama: Coal resources W. C. Culbertson (D) Clinton iron ores of the southern Appalachians R. P. Sheldon (D) *Warrior quadrangle (coal) W. C. Culbertson (D) Pre-Selma Cretaceous rocks of Alabama and adjacent States L. C. Conant (Tripoli, Libya) Mesozoic rocks of Florida and eastern Gulf coast P. L. Applin (Jackson, Miss.) Limestone terrane hydrology W. J. Powell (g, Tuscaloosa, Ala.) A—lll Alabama—Continued Artesian water in Tertiary limestones in Florida, southern Georgia and adjacent parts of Alabama and South Carolina V. T. Stringfield (W, W) Unit graphs and infiltration rates, Alabama (surface water) L. B. Peirce (s, Montgomery, Ala.) Stream profiles, Alabama (surface water) L. B. Peirce (s, Montgomery, Ala.) Bridge-site studies, Alabama L. B. Peirce (s, Montgomery, Ala.) Local floods, Alabama L. B. Peirce (s, Montgomery, Ala.) Extending small-area flood records, Alabama L. B. Peirce (s, Montgomery, Ala.) Autauga County (ground water) J. C. Scott (g, Tuscaloosa, Ala.) Bullock County (ground water) J. C. Scott (g, Tuscaloosa, Ala.) Calhoun County (ground water) J. C. Warman (g, Tuscaloosa, Ala.) Geologic and hydrologic profiles in Clarke County L. D. Toulmin (g, Tuscaloosa, Ala.) Colbert County (ground water) H. B. Harris (g, Tuscaloosa, Ala.) Escambia County (ground water) J. W. Cagle (g, Tuscaloosa, Ala.) Etowah County (ground water) L. V. Causey (g, Tuscaloosa, Ala.) Franklin County (ground water) R. R. Peace (g, Tuscaloosa, Ala.) Hale County (ground water) Q. F. Paulson (g, Tuscaloosa, Ala.) Lauderdale County (ground water) H. B. Harris (g, Tuscaloosa, Ala.) Limestone County (ground water) W. M. McMaster (g, Tuscaloosa, Ala.) Morgan County (ground water) C. L. Dodson (g, Tuscaloosa, Ala.) Pickens County (ground water) J. G. Newton (g, Tuscaloosa, Ala.) St. Clair County (ground water) L. V. Causey (g, Tuscaloosa, Ala.) Tuscaloosa County (ground water) Q. F. Paulson (g, Tuscaloosa, Ala.) Athens and vicinity (ground water) W. M. McMaster (g, Tuscaloosa, Ala.) Geologic and hydrologic profile along the Chattahoochee River L. D. Toulmin (g, Tuscaloosa, Ala.) _ Huntsville and Madison County (ground water) T. H. Sanford (g, Tuscaloosa, Ala.) Russellville and vicinity (ground water) R. R. Peace (g, Tuscaloosa, Ala.) Sylacauga Area (ground water) G. W. Swindel (g, Tuscaloosa, Ala.) Sylacauga area (petrography) C. E. Shaw (g, Tuscaloosa, Ala.) Alaska: General geology : Index of literature on Alaskan geology E. H. Cobb (M) A—112 Alaska—Continued General geology—Continued Tectonic map G. Gryc (W) Glacial map D. M. Hopkins (M) Physiographic divisions C. Wahrhaftig (M) Rock types map of Alaska L. A. Yehle (W) Landform map of Alaska H. W. Coulter (W) Vegetation map of Alaska L. A. Spetzman (W) Climatic map of Alaska A. T. Fernald (W) Compilation of geologic maps, 1 : 250,000 quadrangles W. H. Condon (M) M‘Regional geology and mineral resources, southeastern Alaska R. A. Loney (M) *Eastern Aleutian Islands R. E. Wilcox (D) *Western Aleutian Islands R. E. Wilcox (D) *Surficial geology of the Barter Island-Mt. Chamberlin area 0. R. Lewis (W) “Buckland and Huslia Rivers area, west-central Alaska \V. W. Patton, Jr. (M) a”Eastern Chugach Mountains traverse D. J. Miller (M) "Fairbanks quadrangle F. R. Weber (College, Alaska) *Petrology and volcanism, Katmai National Monument G. H. Curtis (M) “Livengood quadrangle B. Taber (M) *Mount Michelson area E. G. Sable (Ann Arbor, Mich.) *Windy-Curry area R. Kachadoorian (M) *Southern Wrangell Mountains E. M. MacKevett, Jr. (M) “Lower Yukon—Norton Sound region J.M. Hoare (M) "Upper Yukon River traverse E. E. Brabb (M) Mineral resources: Metallogenic provinces C. L. Sainsbury (M) Geochemical prospecting techniques R. M. Chapman (D) Miscellaneous mineral resource investigations E. M. MacKevett, Jr. (M) "Klukwau iron district E. C. Robertson (\V) Quicksilver deposits, southwestern Alaska E. M. MacKevett, Jr. (M) "Lower Kuskokwim-Bristol Bay region (mercury-antimony- zinc) J. M. Hoare (M) "Southern Brooks Range (copper, precious metals) W. P. Brosgé (M) GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Alaska—Continued Mineral resources—Continued *Nome 0—1 and D—l quadrangles (gold) C. L. Hummel (M) *Tofty placer district (gold, tin) D. M. Hopkins (M) Seward Peninsula tin investigations P. L. Killeen (W) Uranium—thorium reconnaissance E. M. MacKevett, Jr. (M) *Beluga-Yentna area (coal) F. F. Barnes (M) *Matanuska coal field F. F. Barnes (M) Matanuska stratigraphic studies (coal) A. Grantz (M) *Nenana coal investigations C. Wahrhaftig (M) “Gulf of Alaska province (petroleum) D. J. Miller (M) **Northern Alaska petroleum investigations G. Gryc (W) *Iniskin-Tuxedni region (petroleum) R. L. Detterman (M) **Nelchina area (petroleum) A. Grantz (M) “Lower Yukon—Koyukuk area (petroleum) W. W. Patton, Jr. (M) *Heceta-Tuxekan area (high-calcium limestone) G. D. Eberlein (M) Engineering geology and permafrost: Engineering soils map of Alaska '1‘. N. V. Karlstrom (XV) *Surficial and engineering geology studies and construction materials sources T. L. Péwé (College, Alaska) Arctic ice and permafrost studies A. H. Lachenbruch (M) Origin and stratigraphy of ground ice in central Alaska T. L. Péwé (College, Alaska) *Surficial geology of the Anchorage-Matanuska Glacier area (construction-site planning) T. N. V. Karlstrom (W) *Surficial geology of the Big Delta Army Test Area (con- truction-site planning) G. W. Holmes (W) *Surficial geology of the Big Delta-Fairbanks area (construc- tion-site planning) H. L. Foster (W) *Nuclear test-site evaluation, Chariot G. D. Eberlein (M) \ *Surficial geology of the lower Chitina Valley (construction- site planning) L. A. Yehle (W) *Surflcial geology of the northeastern Copper River (con- struction-site planning) 0. J. Ferrians, Jr. (Glennallen, Alaska) *Surficial geology of the southeastern Copper River (con- struction-site planning) D. R. Nichols (W) *Surflcial geology of the southwestern Copper River basin (construction-site planning) J. R. Williams (W) REGIONAL INVESTIGATIONS IN PROGRESS Alaska—Continued Engineering geology and permafrost—Continued *Surflcial geology of the eastern Denali Highway (construc- tion-site planning) D. R. Nichols (W) *Surficial geology of the Johnson River district (construction- site planning) H. L. Foster (W) "Surficial geology of the Kenai lowland (construction-site planning) T. N. V. Karlstrom (W) “Surficial geology of the Kobuk River valley (construction- site planning) A. T. Fernald (W) *Mt. Hayes D—3 and D-4 quadrangles (construction-site plan- ing) T. L. Péwé (College, Alaska) *Surficial geology of the Seward-Portage Railroad (construc- tion—site planning) T. N. V. Karlstrom (W) *Surficial geology of the Slana-Tok area (construction-site planning) H. R. Schmoll (W) ‘Surficial geology of the Susitna—Maclaren River area (con- struction-site planning) D. R. Nichols (W) "Engineering geology of Talkeetna-McGrath highway Florence Weber (College, Alaska) *Surficial geology of the Upper Tanana River (construction- site planning) A. T. Fernald (W) *Surficial geology of the Valdez-Tiekel belt (construction- site planning) H. W. Coulter (W) "Engineering geology of Yukon-Koyukuk lowland F. R. Weber (College, Alaska) Paleontology : Central Alaska Cenozoic D. M. Hopkins (M) Cenozoic mollusks F. S. MacNeil (M) Cretaceous Foraminifera of the Nelchina area H. R. Bergquist (W) Geophysical studies: Aeromagnetic surveys G. E. Andreasen (W) Regional gravity surveys D. F. Barnes (M) Aerial radiological monitoring surveys, Chariot site R. G. Bates (W) Water resources: General inventory of ground water R. M. Waller (g, Anchorage, Alaska) Relationship of permafrost to ground water J. R. Williams (g, Anchorage, Alaska) Water-supply investigations for US. Air Force A. J. Feulner (g, Anchorage, Alaska) Anchorage area (ground water) D. J. Cederstrom (g, W) Water utilization at Anchorage R. M. Waller (g, Anchorage, Alaska) Chugiak area (ground water) R. M. Waller (g, Anchorage, Alaska) Fairbanks area (ground water) D. J. Cederstrom (g, W) A—113 Alaska—Continued Water resources—Continued Fort Greely (ground water) R. M. Waller (g, Anchorage, Alaska) Homer area (ground water) :3. M. Waller (g, Anchorage, Alaska) Project Chariot (ground water) R. M. Waller (g, Anchorage, Alaska) Arizona: General geology: Arizona state geologic map J. R. Cooper (D) Devonian rocks and paleogeography of central Arizona C. Teichert (D) Devonian rocks of northwestern Arizona C. Teichert (D) Stratigraphy of the Redwall limestone E. D. McKee (D) History of Supai-Hermit formations E. D. McKee (D) *Geology of southern Cochise County P. T. Hayes (D) *Elgin quadrangle R. B. Raup (M) *Upper Gila River basin, Arizona-New Mexico R. B. Morrison (D) *Holy Joe Peak quadrangle M. H. Krieger (M) Lochiel and Nogales quadrangles F. S. Simons (D) Meteor Crater E. M. Shoemaker (M) Diatremes, Navajo and Hopi Indian Reservations E. M. Shoemaker (M) *Eastern Mogollon Rim area E. J. McKay (D) Mineral resources: Geochemical halos of mineral deposits, Arizona L. C. Huff (D) Studies of uranium deposits H. C. Granger (D) “Compilation of Colorado Plateau geologic maps (uranium, vanadium) D. G. Wyant (D) Relative concentrations of chemical elements in rocks and ore deposits of the Colorado Plateau (uranium, vanadium, copper) A. T. Miesch (D) Uranium-vanadium deposits in sandstone, with emphasis on the Colorado Plateau R. P. Fischer (D) Colorado Plateau botanical prospecting studies F. J. Kleinhampl (M) Clay studies, Colorado Plateau L. G. Schultz (D) Lithologic studies, Colorado Plateau R. A. Cadigan (D) Stratigraphic studies, nadium) L. C. Craig (D) Triassic stratigraphy and lithology of the Colorado Plateau (uranium, copper) J. H. Stewart (D) California and Colorado Plateau (uranium, va- A—l 14 GEOLOGICAL SURVEY RESEARCH 1961—SYN0PSIS OF RESULTS Arizona—Continued Arizona—Continued Mineral resources—Continued San Rafael group stratigraphy, Colorado Plateau (ura— nium) J. C. Wright (D) *Carrizo Mountains area, Arizona-New Mexico (uranium) J. D. Strobell (D) Uranium deposits of the Dripping Spring quartzite of southeastern Arizona H. C. Granger (D) East Vermillion Cliffs area (uranium, vanadium) R. G. Peterson (Boston, Mass.) *Bradshaw Mountains (copper) C. A. Anderson (W) *Christmas quadrangle (copper, iron) C. R. Willden (M) *Globe—Miami area (copper) N. P. Peterson (Globe, Ariz.) *Klondyke quadrangle (copper) F. S. Simons (D) *Contact—metamorphic deposits of the Little Dragoons area (copper) J. R. Cooper (D) *Mammoth and Benson quadrangles (copper) S. C. Creasey (M) *Prescott-Paulden area (copper) M. H. Krieger (M) *Twin Buttes area (copper) J. R. Cooper (D) *McFadden Peak and Blue House Mountain quadrangles (asbestos) A. F. Shride (D) _ *Fuels potential of the Navajo Reservation, Arizona and Utah R. B. O’Sullivan (D) Geophysical studies: Great Basin geophysical studies D. R. Mabey (M) Colorado Plateau regional geophysical studies H. R. Joesting (W) Water resources: The geohydrolog'ic environment as related to water utiliza- tion in arid lands E. S. Davidson (g, Tucson, Ariz.) Evapotranspiration theory and measurement 0. E. Leppanen (h, Phoenix, Ariz.) Hydrologic effect of vegetation modification R. C. Culler (h, Tucson, Ariz.) Use of water by saltcedar in evapotranspirometer compared with energy budget and mass transfer computa- tion (Buckeye) T. E. A. Van Hylckama (h, Phoenix, Ariz.) Lower Colorado River Basin hydrology C. C. McDonald (g, Yuma, Ariz.) Central Apache County (ground water) J. P. Akers (g, Tucson, Ariz.) Northwestern Pinal County (ground water) W. F. Hardt (g, Tucson, Ariz.) Big Sandy valley (ground water) W. Kam (g, Tucson, Ariz.) Effect of removing riparian vegetation, Cottonwood Wash, Arizona (water) J. E. Bowie (s, Tucson, Ariz.) Water resources—Continued Flagstaff area (ground water) J'. P. Akers (g, Tucson, Ariz.) Hydrologic regimen and volumetric analysis of Upper Gila River Sumsion, C. T. (h, Tucson, Ariz.) Fort Huachuca (ground water) H. G. Page (g, Tucson, Ariz.) Luke Air Force Base (ground water) J. M. Cahill (g, Tucson, Ariz.) Navajo Indian Reservation (ground water) M. E. Cooley (g, Tucson, Ariz.) Papago Indian Reservation (ground water) L. A. Heindl (g, W) Rainbow Valley-Waterman Wash (ground water) F. R. Twenter (g, Tucson, Ariz.) Rillito basin, Arizona (surface water) J. J. Ligner (s, Tucson, Ariz.) Deep aquifers in the Salt River valley D. G. Metzger (g, Tucson, Ariz.) San Simon basin (ground water) N. D. White (g, Tucson, Ariz.) SnowflakeTaylor area (ground water) P. W. Johnson (g, Tucson, Ariz.) Study of channel flood-plain aggradation Tusayan Washes R. F. Hadley (h, D) Verde Valley (ground water) D. G. Metzger (g, Tucson, Ariz.) Willcox basin (ground water) S. G. Brown (g, Tucson, Ariz.) Arkansas : Barite deposits D. A. Brobst (D) *Arkansas Basin (coal) B. R. Haley (D) *Ft. Smith district, Arkansas and Oklahoma (coal and gas) T. A. Hendricks (D) Magnet Cove niobium investigations L. V. Blade (Paducah, Ky.) *Northern Arkansas oil and gas investigations E. E. Glick (D) Aeromagnetic studies in the Newport, Arkansas, and Ozark bauxite areas A. Jaspersen (W) Artificial recharge of aquifers R. T. Sniegocki (g, Little Rock, Ark.) Flood investigations R. C. Christensen (s, Fort Smith, Ark.) Low-flow gaging J. D. Warren (s, Fort Smith, Ark.) Bradley, Calhoun, and Ouachita Counties (ground water) D. R. Albin (g, Little Rock, Ark.) Crittenden County (ground water) R. O. Plebuch (g, Little Rock, Ark.) Ground water along US. Highway 70 from Pulaski County to Crittenden County H. N. Halberg (g, Little Rock, Ark.) Arkansas River Valley M. S. Bedinger (g, Little Rock, Ark.) Arkansas River Valley reconnaissance (ground water) R. M. Cordova (g, Little Rock, Ark.) Artificial recharge, Grand Prairie Region (ground water) R. T. Sniegocki (g, Little Rock, Ark.) REGIONAL INVESTIGATIONS IN PROGRESS Arkansas—Continued Smackover Creek basin (chemical quality of surface waters) H. G. Jeffery (q, Fayetteville, Ark.) Surface-water resources of the White River basin, 1948—59 M. E. Schroeder (q, Fayetteville, Ark.) California : General geology: *California Coast Range ultramafic rocks E. H. Bailey (M) Glaucophane schist terranes within the Franciscan for- mation R. G. Coleman (M) *San Andreas fault L. F. Noble, Valyermo (Calif.) *Ash Meadows quadrangle, California-Nevada C. S. Denny (W) *Big Maria Mountains quadrangle W. B. Hamilton (D) *Blanco Mountain quadrangle C. A. Nelson (L0s Angeles, Calif.) *Petrology of the Burney area G. A. Macdonald (Honolulu, Hawaii) *Death Valley C. B. Hunt (D) *Funeral Peak quadrangle H. D. Drewes (D) *Independence quadrangle D. C. Ross (M) *Northern Klamath Mountains, Condrey Mountain quad- rangle P. E. Hotz (M) *Merced Peak quadrangle D. L. Peck (M) ‘Mt. Pinchot quadrangle J. G. Moore (M) *Salinas Valley D. L. Durham (M) *Geology of San Nicolas Island J. G. Vedder (M) Glacial geology of the west central Sierra Nevada region F. M. Fryxell (Rock Island, Ill.) *Weaverville, French Gulch and Hayfork quadrangles, southern Klamath Mountains W. P. Irwin (M) Mineral resources: Western oxidized. zinc deposits A. V. Heyl (w') Geochemical halos of mineral deposits, California and Arizona L. C. Huff (D) Origin of the borate—bearing marsh deposits of Cali- fornia, Oregon, and Nevada (boron) W. C. Smith (M) *Furnace Creek area (boron) J. F. McAllister (M) ‘Western Mojave Desert (boron) T. W. Dibblee, Jr. (M) *Geology and origin of the saline deposits of Searles Lake (boron) ‘ G. I. Smith (M) *Bishop tungsten district P. C. Bateman (M) A—115 ‘ California—Continued Mineral resources—Continued *Geologic study of the Sierra Nevada batholith (tung- sten, gold, base metals) P. C. Bateman (M) *Eastern Sierra tungsten area: Devil’s Postpile, Mt. Morrison, and Casa Diablo quadrangles (tung- sten, base metals) C. D. Rinehart (M) Structural geology of the Sierra foothills mineral belt (Copper, zinc, gold, chromite) L. D. Clark (M) *Mt. Diablo area (quicksilver, copper, gold, silver) E. H. Pampeyan (M) *New York Butte quadrangle (lead—zinc) W. C. Smith (M) *Panamint Butte quadrangle including special geochemi- cal studies. (lead-silver) W. E. Hall (W) Lateritic nickel deposits of the Klamath Mountains, Ore- gon-California P. E. Hotz (M) *Easter'n Los Angeles basin (petroleum) J. E. Schoellhamer (M) *Northwest Sacramento Valley (petroleum) R. D. Brown, Jr. (M) *Southeastern Ventura basin (petroleum) E. L. Winterer (Los Angeles, Calif.) Engineering Geology: *Surficial geology of the Beverly Hills, Venice, and To- panga quadrangles, Los Angeles (urban geology) J. T. McGill (Los Angeles, Calif.) Malibu Beach quadrangle (urban geology) R. F. Yerkes (M) *Oakland East quadrangle (urban geology) D. H. Radbruch (M) *San Francisco Bay area, San Francisco North quad- rangle (urban geology) J. Schlocker (M) *San Francisco Bay area, San Francisco South quad- rangle (urban geology) M. G. Bonilla. (M) Geophysical studies: Great Basin geophysical studies D. R. Mabey (M) Gravity studies, California-Nevada region D. J. Stuart (D) Gravity studies, southern Cascade Mountains, L. C. Pakiser (D) Aerial radiological monitoring surveys, Los Angeles K. G. Books (W) Rocks and structures of the Los Angeles basin, and their gravitational effects T. H. McCulloh (Riverside, Calif.) Aerial radiological monitoring surveys, San Francisco J. A. Pitkin (W) Geophysical study in the Sierra Nevada Mountains H. W. Oliver (W) Gravity studies, Sierra Valley W. H. Jackson (1)) Paleontology : Foraminifera of the Lodo formation, central California M. C. Israelsky (M) A—l 16 California—Continued Paleontology—Continued Cenozoic Foraminifera, Colorado Desert P. J. Smith (M) Geology and paleontology of the Cuyama Valley area J. G. Vedder (M) Water resources: Hydrologic effect of urbanization A. 0. Waananen (h, M) North Pacific Coast area (Surface water) E. E. Harris (s, M) Water loss and gain studies in California W. 0. Peterson (s, M) Tidal flow measurement S. E. Rantz (s, M) California coastal basins hydrology S. E. Rantz (s, M) Floods from small areas in California L. E. Young (s, M) Clastic sedimentation in a 'bolson environment. L. K. Lustig (q, Boston, Mass.) Solute-solid relations in lacustl’ine closed basins of the alkali-carbonate type. B. F. Jones (q, W) A study of the occurrence and distribution of trace elements in fresh and saline waters. W. D. Silvey (q, Sacramento, Calif.) . Processes affecting solute composition and minor element distribution in lacustrine closed basins. B. F. Jones (q,W) Mineral constituents in ground water J. H. Feth (g, M) Mechanics of aquifers J. F. Poland (g, Sacramento, Cailf.) Agricultural Research Service soil-moisture study R. E. Evenson (g, Sacramento, Calif.) Lower Colorado River Basin hydrology C. C.McDona1d (g, Yuma, Ariz.) Alameda Creek basin (pollution of surface waters) R. T. Kiser (q, Sacramento, Calif.) Cache Creek basin (sedimentation conditions) George Porterfleld (q, Sacramento, Calif.) Camp Pendleton Marine Corps Base (ground water) J. S. Bader (g, Sacramento, Calif.) Dale Lake area (ground water) G. M. Hogenson (g, Sacramento, Calif.) Death Valley National Monument (ground water) F. Kunkel (g, Sacramento, Calif.) Ducor-Famoso area (ground water) G. S. Hilton (g, Sacramento, Calif.) Edwards Air Force Base (ground water) W. R. Moyle (g, Sacramento, Calif.) Fruitvale oil field (Quality of ground waters) B. V. Salotto (q, Sacramento, Calif.) Furnace Creek and Pinto Basin (ground water) G. M. Hogenson (g, Sacramento, Calif.) Hoopa Valley (ground water) J. L. Poole (g, Sacramento, Calif.) Inyokern Naval Ordnance Test Station (ground water) F. Kunkel (g, Sacramento, Calif.) Kaweah-Tule area (ground water) M. G. Croft (g, Sacramento, Calif.) Kern River fan (ground water) R. H. Dale (g, Sacramento, Calif.) GEOLOGICAL SURVEY RESEARCH 1961,—SYNOPSIS OF RESULTS California—Continued Water resources—Continued Lake Pillsbury sedimentation survey George Porterfleld (q, Sacramento, Calif.) Lower Mojave area, west part (ground water) G. M. Hogenson (g, Sacramento, Calif.) Oak Mountain Air Force Facility (ground water) G. A. Miller (g, Sacramento, Calif.) Point Arguello (ground water) R. E. Evenson (g, Sacramento, Calif.) Point Mugu area (ground water) R. W. Page (g, Sacramento, Calif.) San Antonio Valley (ground water) R. E. Evenson (g, Sacramento, Calif.) Determination of evaporation coefficient for reservoirs in San Diego G. E. Koberg (h, D) San Francisco Bay barriers (ground water) G. M. Hogenson (g, Sacramento, Calif.) San Nicolas Island (ground water) R. W. Page (g, Sacramento, Calif.) Santa Barbara County (ground water) R. E. Evenson (g, Sacramento, Calif.) Santa Maria Valley (ground water) R. E. Evenson (g, Sacramento, Calif.) Sierra Ordnance Depot (ground water) G. S. Hilton (g, Sacramento, Calif.) South Coast basins (ground water) R. E. Evenson (g, Sacramento, Calif.) Stony Gorge Reservoir sedimentation survey C. A. Dunnam (q, Sacramento, Calif.) Tecolote Tunnel, California, effect on spring flow '8. E. Rantz (s, M) Twentynine Palms Marine Corps Training Center (ground water) H. B. Dyer (g, Sacramento, Calif.) Colorado : General geology: Investigation of Jurassic stratigraphy, Wyoming and northwestern Colorado G. N. Pipiringos (D) Upper Cretaceous stratigraphy, northwestern Colorado and northeastern Utah A. D. Zapp (D) Stratigraphy and paleontology of the Pierre shale, Front Range area, Colorado and Wyoming W. A. Cobban and G. R. Scott (D) Pennsylvanian and Permian stratigraphy, Rocky Mountain Front Range, Colorado and Wyoming E. K. Maughan (D) Petrology and geochemistry of the Laramide intrusives in the Colorado Front Range G. Phair (W) Significance of lead-alpha age variation in batholiths of the Colorado Front Range D. Gottfried (W) Petrology and geochemistry of the Boulder Creek batholith, Colorado Front Range G. Phair (W) Magmatic difierention Princeton area P. Toulmin 3d (W) *Mountain front area, east-central Front Range D. M. Sheridan (D) south-central in calc-alkaline intrusives, Mt. REGIONAL INVESTIGATIONS IN PROGRESS Colorado—Continued General geology—Continued Tufts of the Green River formation R. L. Griggs (D) *Cameron Mountain quadrangle M. G. Dings (D) *Glenwood Springs quadrangle N. W. Bass (D) *Upper South Platte River, North Fork G. R. Scott (D) Mineral resources: .Western oxidized zinc deposits A. V. Heyl (W) ‘Lake George district (beryllium) C. C. Hawley (D) Volcanic and economic geology of the Creede caldera (base and precious metals; fluorspar) T. A. Steven (D) Ore deposition at Creede E. W. Roedder (W) *Central City-Georgetown area, including studies of the Precambrian history of the Front Range (base, precious, and radioactive metals) P. K. Sims (D) ‘Holy Cross quadrangle and the Colorado mineral belt (lead, zinc, silver, copper, gold) .0. Tweto (D) ’Minturn quadrangle (zinc, silver, copper, lead, gold) T. S. Lovering (D) *Rico district (lead, zinc, silver) E. T. McKnight (W) *San Juan mining area, including detailed study of the Silverton Caldera (lead, zinc, silver, gold, copper) R. G. Luedke (W) *Tenmile Range, including the Kokomo mining district (base and precious metals) A. H. Koschmann (D) *Poncha Springs and Saguache quadrangles (fluorspar) R. E. Van Alstine (W) *Powderhorn area, Gunnison County (thorium) J. 0. Olson (D) *Wet Mountains (thorium, base and precious metals) M. R. Brock (W) Wallrock alteration and its relation to thorium deposition in the Wet Mountains G. Phair (W) *Uranium deposits in the Front Range P. K. Sims (D) "Compilation of Colorado Plateau geologic maps (uranium, vanadium) D. G. Wyant (D) Uranium-vanadium deposits in standstone, with emphasis on the Colorado Plateau R. P. Fischer (D) Relative concentrations of chemical elements in rocks and ore deposits of the Colorado Plateau (uranium. vanadium, copper) A. T. Miesch (D) Colorado Plateau botanical prospecting studies F. J. Kleinhampl (M) Clay studies, Colorado Plateau L. G. Schultz (D) Lithologic studies, Colorado Plateau R. A. Cadigan (D) 608400 0—‘61r—9 A—117 Colorado—Continued Mineral resources—Continued Stratigraphic studies, Colorado Plateau (uranium, va- nadium) L. 0. Craig (D) Triassic stratigraphy and lithology of the Colorado Plateau (uranium, copper) J. H. Stewart (D) San Rafael group stratigraphy, Colorado Plateau (uranium) J. C. Wright (D) *Baggs area, Wyoming and Colorado (uranium) G. E. Prichard (D) ‘Bull Canyon district (vanadium, uranium) C. H. Roach (D) Exploration for uranium deposits in the Gypsum Valley district 0. F. Withington (\V) *Klondike Ridge area salines) J. D. Vogel (D) *La Sal area, Utah-Colorado (uranium, vanadium) W. D. Carter (Santiago, Chile) *Lisbon Valley area, Utah-Colorado (uranium, vanadium, copper) G. W. Weir (M) *Maybell-Lay area, Moffat County (uranium) M. J. Bergin (W) *Ralston Buttes (uranium) D. M. Sheridan (D) ‘Western San Juan Mountains (uranium, vanadium, gold) A. L. Bush (W) ' ‘Slick Rock district (uranium, vanadium) D. R. Shawe (D) Uravan district (vanadium, uranium) R. L. Boardman (W) *Ute Mountains (uranium, vanadium) E. B. Ekren (D) *Carbondale coal field J. R. Donnell (D) *Trinidad coal field B. B. Johnson (D) *Animas River area, Colorado and New Mexico (coal, oil, and gas) H. Barnes (D) *Eastern North Park (coal, oil, and gas) D. M. Kinney (W) *Western North Park (coal, oil, and gas) W. J. Hail (D) Subsurface geology of the Dakota sandstone, Colorado and Nebraska (oil and gas) N. W. Bass,(D) “Oil shale investigations D. 0. Duncan (W) *Grand-Battlement Mesa oil shale J. R. Donnell (D) Engineering geology and geophysical studies: Gravity profile of the southern Rocky Mountains, Colorado D. J. Stuart (D) Colorado Plateau regional geophysical studies H. R. Joesting (W) *Air Force Academy (construction-site planning) D. J. Varnes (D) (uranium, copper, manganese, A—118 GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Colorado—Continued Engineering geology and geophysical studies—Continued Black Canyon of the Gunnison River (construction-site planning) W. R. Hansen (D) *Upper Green River valley (construction-site planning) W. R. Hansen (D) *Denver metropolitan area (urban geology) R. M. Lindvall (D) *Golden quadrangle (urban geology) R. Van Horn (D) *Morrison quadrangle (urban geology) J. H. Smith (D) *Pueblo and vicinity (urban geology) G. R. Scott (D) Engineering geology of the Roberts Tunnel C. S. Robinson (D) Water resources: Characteristics of municipal water supplies in Colorado E. A. Moulder (g, D) Effects of exposure on slope morphology R. F. Hadley (h, D) Mechanics of hillslope erosion S. A. Schumm (h, D) Plant species or communities as indicators of soil moisture availability F. A. Branson (h, D) Effects of particle-size distribution on mechanics of flow in alluvial channels D. B. Simons (q, Fort Collins, Colo.) Effects of sediment characteristics on fluvial morphology hydraulics S. A. Schumm (h, D) Effects of grazing exclusion in Badger Wash area G. C. Lusby (h, D) Bent County (ground water) J. H. Irwin (g, D) Flood inundation, Boulder County C. T. Jenkins (s, D) Ogalalla formation, eastern Cheyenne and Kiowa Counties (ground water) A. J. Boettcher (g, D) Huerfano County (ground water) T. G. McLaughlin (g, D) Kit Carson County (ground water) G. H. Chase (g, D) Otero County and part of Crowley County (ground water) W. G. Weist (g, D) Prowers County (ground water) P. T. Voegel (g, D) Pueblo and Fremont Counties (ground water) H. E. McGovern (g, D) Washington County (ground water) H. E. McGovern (g, D) Yuma County (ground water) W. G. Weist (g, D) Big Sandy valley below Limon (ground water) D. L. Coflin (g, D) Cache La Poudre valley (ground water) L. A. Hershey (g, D) Colorado National Monument (general geology) S. W. Lohman (g, D) Denver Basin (ground water) G. H. Chase (g, D) Colorado—Continued Water resources—Continued Fountain and Jimmy Camp valleys (ground water) E. D. Jenkins (g, D) Grand Junction artesian area (ground water) S. W. Lohman (g, D) Fluvial sedimentation and runoff in Kiowa Creek J. C. Mundorff (q, Lincoln, Nebr.) Investigation of trap efficiencies of K—79 Reservoir, Kiowa Creek basin J. C. Mundorff ((1, Lincoln, Nebr.) North and Middle Parks (ground water) P. T. Voegel (g, D) Rocky Mountain National Park (ground water) D. L. Coffin (g, D) Ute Mountain Ute Indian Reservation (ground water) J. H. Irwin (g, D) Connecticut : General geology: *Ansonia, Mount Carmel, and Southington quadrangles; bed- rock geologic mapping C. E. Fritts (D) *Ashaway quadrangle, Rhode Island—Connecticut; bedrock geologic mapping T. G. Feininger (Boston, Mass.) *Ashaway and Watch Hills quadrangles, Connecticut-Rhode Island; surflcial geologic mapping J. P. Schafer (Boston, Mass.) *Avon and New Hartford quadrangles R. W. Schnabel (D) *Bristol and New Britain quadrangles H. E. Simpson (D) ‘Broad Brook and Manchester; quadrangles surficial geo- logic mapping R. B. Colton (D) *Columbia, Fitchville, Norwich, Marlboro, and Willimantic quadrangles; bedrock geologic mapping G. L. Snyder (D) *Durham quadrangle; surficial geologic mapping H. E. Simpson (D) *Fitchville and Norwich quadrangles; surficial geologic mapping P. M. Hanshaw (D) *Hampton and Scotland quadrangles; bedrock geologic map— ping H. R. Dixon (D) *Meriden quadrangle P. M. Hanshaw (D) *Montville, New London, Niantic, and Uncasville quadrangles R. Goldsmith (D) *Mystic and Old Mystic quadrangles; bedrock geologic map- ping R. Goldsmith (D) *Springfield South quadrangle, Massachussets and Conneti- cut. J. H. Hartshorn (Boston, Mass.) *Tarrifville and Windsor Locks quadrangles; bedrock geo- logic mapping R. W. Schnabel (D) *Thompson quadrangle, Connecticut-Rhode Island P. M. Hanshaw (Boston, Mass.) *Watch Hill quadrangle, Connecticut-Rhode Island; bed- rock geologic mapping G. E. Moore, Jr. (Columbus, Ohio) REGIONAL INVESTIGATIONS IN PROGRESS A—119 Connecticut—Continued General geology—COHtinued *Stratigraphy and structure of Taconic rocks E-an Zen (W) Water resources: Recognition of late glacial substages in New England and New York J. E. Upson (g, Mineola, N.Y.) North-central Connecticut (ground water) R. V. Cushman (g, Middletown, Conn.) Bristol-PlainvilleSouthington area (ground water) A. M. LaSala, Jr. (g, Middletown, Conn.) Farmington-Granby area (ground water) A. D. Randall (g, Middletown, Conn.) Hartford North Quadrangle R. V. Cushman (g, Middletown, Conn.) Ground—water salinity and pumpage in New Haven R. V. Cushman (g, Middletown, Conn.) Lower Quinebaug basin (ground water) A. D. Randall (g, Middletown, Conn.) Lower Quinnipiac and Mill River lowlands (ground water) A. M. La‘Sala, Jr. (g, Middletown, Conn.) Tariffville quadrangle (Surficial geology) A. D. Randall (g, Middletown, Conn.) Voluntown quadrangle (ground water) K. E. Johnson (g, Providence, RI. ) Waterbury-Bristol area (ground water) R. V. Cushman (g, Middletown, Conn.) Watch Hill quadrangle (ground water) K. E. Johnson (g, Providence, RI.) Delaware: Water-table and engineering mapping D. H. Boggess (g, Newark, Del.) Salinity conditions of Lower Delaware River basin D. McCartney (q, Philadelphia, Pa.) Salt-water encroachment in the Lewes-Rehoboth area D. R. Rima (g, Newark, Del.) New Castle County (ground water) D. R. Rima (g, Newark, Del.) Newark area (ground water) D. R. Rima (g, Newark, Del.) Red Clay Valley (ground water) D. H. Boggess (g, Newark, Del.) Florida: Subsurface Paleozoic rocks of Florida J. M. Berdan (W) Mesozoic rocks of Florida and eastern Gulf Coast P. L. Applin (Jackson, Miss.) *Land-pebble phosphate deposits J. B. Cathcart (D) Phosphate deposits of northern Florida G. H. Espenshade (W) Artesian water in Tertiary limestones in Florida, southern Georgia, and adjacent parts of Alabama and South Carolina V. T. Stringfield (w, W) Drought of 1954—56 in Florida R. W. Pride (s, Ocala, Fla.) Physical characteristics of selected Florida lakes W. E. Kenner (s, Ocala, Fla.) Bridge-site studies, Florida (surface water) R. W. Pride (s, Ocala, Fla.) Mechanics of diffusion, fresh and salt water H. H. Cooper (g, Tallahassee, Fla.) Florida—Continued Alachua, Bradford, Clay, and Union Counties (water resources) W. E. Clark (g, Tallahassee, Fla.) Northeastern Broward County (ground water) G. R. Tarver (g, Tallahassee, Fla.) Central Broward County (ground water) H. Klein (g, Tallahassee, Fla.) Collier County (ground water) H. J. McCoy (g, Tallahassee, Fla.) Salt-water encroachment studies in Dade County H. Klein (g, Tallahassee, Fla.) Area B, Dade County (ground water) C. B. Sherwood (g, Tallahassee, Fla.) Duval, Nassau, and Baker Counties (ground water) Tarver, G. (g, Tallahassee, Fla.) Escambia and Santa Rosa Counties, Florida (water) R. H. Musgrove (s, Ocala, Fla.) Glades and Hendry Counties (ground water) W. F. Lichter (g, Tallahassee, Fla.) Orange County (water resources) W. F. Lichter (g, Tallahassee, Fla.) Polk County (ground water) H. G. Stewart (g, Tallahassee, Fla.) Polk County (surface water) R. C. Heath (s, Ocala, Fla.) St. Johns, Flagler, and Putnam Counties (ground water) D. W. Brown (g, Tallahassee, Fla.) St. Johns, Flagler, and Putnam Counties, Florida (surface water) W. E. Kenner (s, Ocala, Fla.) Everglades National Park (water) J. H. Hartwell (s, Ocala, Fla.) Green Swamp area, Florida (water) R. W. Pride (s, Ocala, Fla.) Hillsborough River floods of 1960 R. W. Pride (s, Ocala, Fla.) Snake Creek Canal salinity study F. A. Kohout (g, Tallahassee, Fla.) Snapper Creek, Snake Creek, and Levee 30 studies (ground water) C. B. "Sherwood (g, Tallahassee, Fla.) Tampa Bay area (water resources) Grantham, R. ((1y Ocala, Fla.) Georgia : Clinton iron ores of the southern Appalachians R. P. Sheldon (D) . Mesozoic rocks of Florida and eastern Gulf Coast P. L. Applin (Jackson, Miss.) Pre-Selma Cretaceous rocks of Alabama and adjacent States L. C. Conant (Tripoli, Libya) Aerial radiological monitoring surveys, Georgia Nuclear Air- craft Laboratory J. A. MacKallor (W) Aerial radiological monitoring surveys, Savannah River Plant, Georgia and South Carolina R. G. Schmidt (W) River systems studies M. T. Thomson (S, Atlanta, Ga.) Relation of geology to low flow 0. J. Cosner (s, Atlanta, Ga.) Low-flow studies R. F. Carter (s, Atlanta, Ga.) A—120 Georgia—Continued Bridgesites studies (surface water) C. M. Bunch (s, Atlanta, Ga.) Areal flood studies C. M. Bunch (s, Atlanta, Ga.) Flood gaging C. M. Bunch (s, Atlanta, Ga.) Artesian water in Tertiary limestones in Florida, southern Georgia and adjacent parts of Alabama and South Carolina V. T. Stringfield (w, W) Solution subsidence of a limestone terrane in southwest Georgia S. M. Herrick (g, Atlanta, Ga.) Stratigraphy of the Trent marl and related units P. M. Brown (g, Raleigh, N.C.) Paleozoic rock area, Bartow County M. G. Croft (g, Atlanta, Ga.) Paleozoic rock area, Chatooga County (ground water) C. W. Cressler (g, Atlanta, Ga.) Georgia crystalline rock area, Dawson County (ground water) C. W. Sever (g, Atlanta, Ga.) Lee and Sumter Counties (ground water) V. Owen (g, Atlanta, Ga.) Mitchell County (ground water) V. Owen (g, Atlanta, Ga.) Seminole, Decatur, and Grady Counties (ground water) V. Owen (g, Atlanta, Ga.) Paleozoic rock area, Walker County (ground water) 0. W. Cressler (g, Atlanta, Ga.) Salt-water encroachment in the Brunswick area R. L. Wait (g, Atlanta, Ga.) Georgia Nuclear Laboratory area (ground water) J. W. Stewart (g, Atlanta, Ga.) Macon area (ground water) H. E. LeGrand (w, W) Salt—water encroachment in the Savannah area H. B. Counts (g, Atlanta, Ga.) Hawaii: Geological, geochemical and geophysical studies of Hawaiian volcanology J. P. Eaton (Hawaii) Hawaiian volcanoes, thermal and magnetic studies J. H. Swartz (W) High-alumina weathered basalt on Kauai, Hawaii S. H. Patterson (W) Low-flow studies G. T. Hirashima (s, Honolulu, Hawaii) Windward Oahu (ground water) K. J. Takas'aki (g, Honolulu, Hawaii) Central and southern Oahu (ground water) F. N. Visher (g, Honolulu, Hawaii) Mokuleia-‘Vaialua area, Oahu (ground water) D. A. Davis (g, Honolulu, Hawaii) Waianae district, Oahu (ground water) F. N. Visher (g, Honolulu, Hawaii) Idaho: General geology: ”South Central Idaho C. P. Ross (D) “Geologic mapping of the Spokane—\Vallace region, Wash- ington-Idaho A. B. Griggs (M) GEOLOGICAL SURVEY RESEARCH “Nil—SYNOPSIS OF RESULTS Idaho—Continued General geology—Continued ‘Big Creek quadrangle B. F. Leonard (D) *Geochemistry and metamorphism of the Belt Series, Clark Fork and Packsaddle Mountain quad- rangles; Idaho and Montana J. E. Harrison (D) *Leadore, Gilmore, and Patterson quadrangles E. T. Ruzppel (D) *_*Mackay quadrangle C. P. Ross (D) *Metamorphism of the Orofino area A. Hietanen (M) *Owyhee and Mt. City quadrangles, Nevada-Idaho R. R. Coats (M) *Riggins quadrangle W. B. Hamilton (D) \**Regional geology and structure of the central Snake River plain H. A. Powers (D) *Snake River Valley, American Falls region D. E. Trimble (D) *Snake River valley, western region H. A. Powers (D) Petrology of volcanic rocks, Snake River valley H. A. Powers (D) *Yellow Pine quadrangle B. F. Leonard (D) Mineral resources: *Greenacres quadrangle, VVashington-Idaho (high-alumina clays) P. L. Weis (Spokane, Wash.) *Blackbird Mountain area (cobalt) J. S. Vhay (Spokane, Wash.) ‘General geology of the Coeur d’Alene mining district (lead, zinc, silver) A. B. Griggs (M) Ore deposits of the Coeur d’Alene mining district (lead, zinc, silver) V. C. Fryklund, Jr. (Spokane, \Vash.) *Thunder Mountain niobium area, Montana-Idaho R. L. Parker (D) Stratigraphy and resources of the Phosphoria formation (phosphate, minor elements) V. E. McKelvey (W) *Aspen Range—Dry Ridge area (phosphate) V. E. McKelvey (W) *Soda Springs quadrangle, including studies of the Ban- nock thrust zone (phosphate) F. C. Armstrong (Spokane, Wash.) *Radioactive placer deposits of central Idaho D. L. Schmidt (Seattle, Wash.) Geophysical studies: Pacific Northwest geophysical studies W. E. Davis (W) Gravity studies, Snake River Plain D. J. Stuart (D) Gravity studies, Yellowstone area H. L. Baldwin (D) Aerial radiological monitoring surveys, National Reactor Testing Station R. G. Bates (W) REGIONAL INVESTIGATIONS IN PROGRESS Idaho—Continued Water resources: Use of tritium in hydrologic studies C. W. Carlston (g, W) Aberdeen—Springfield area (ground water) H. G. Sisco (g, Boise, Idaho) American Falls Reservoir (ground water) M. J. Mundorff (g, Boise, Idaho) Artesian City area (ground water) E. G. Crosthwaite (g, Boise, Idaho) Dry Creek area (ground water) E. G. Crothwaite (g, Boise, Idaho) Little Lost River basin (water resources) M. J. Mundorff (g, Boise, Idaho) Mud Lake Basin (ground water) P. R. Stevens (g, Boise, Idaho) Geology, hydrology, and waste disposal at the National Reactor Testing Station R. L. Nace (w, W) Hydrology of subsurface waste disposal, National Re- actor Testing Station P. H. Jones (g, Boise, Idaho) Research on hydrology, National Reactor Testing Sta- tion E. H. ‘Valker (g, Boise, Idaho) Salmon Falls creek area (ground water) E. G. Crosthwaite (g, Boise, Idaho) Feasibility of artificial recharge of the Snake Plain aquifer M. J. Mundorff (g, Boise, Idaho) Spokane River Valley (ground water) M. J. Mundorff (g, Boise, Idaho) Illinois: Geologic development of the Ohio River valley L. L. Ray (W) Lower Pennsylvanian floras of Illinois and adjacent States C. B. Read (Albuquerque, N. Mex.) *Stratigraphy of the lead-zinc district near Dubuque J. W. Whitlow (W) *Wisconsin zinc-lead mining district J. W. Whitlow (D) Floods from small areas W. D. Mitchell (s, Champaign, Ill.) Low-flow frequency on Illinois streams W. D. Mitchell (s, Champaign, Ill.) Bridge—site studies (surface water) W. D. Mitchell (s, Champaign, Ill.) Indiana: Geologic development of the Ohio River valley L. L. Ray (W) Lower Pennsylvanian floras of Illinois and adjacent States C. B. Read (Albuquerque, N. Mex.) *Quaternary geology of the Owensboro quadrangle, Ken- tucky-Indiana L. L. Ray (W) Lake mapping and stabilization (surface water) D. C. Perkins (s, Indianapolis, Ind.) Low-flow characteristics R. E. Hoggatt (s, Indianapolis, Ind.) Northwestern Indiana (ground water) J. S. Rosenshein (g, Indianapolis, Ind.) Southeastern Indiana (ground water) J. S. Rosenshein (g, Indianapolis, Ind.) A—121 Indiana—Continued West-central Indiana (ground water) F. A. Watkins (g, Indianapolis, Ind.) Adams County (ground water) F. A. Watkins (g, Indianapolis, Ind.) Clay, Greene, Owen, Sullivan, and Vigo Counties (ground water) F. A. Watkins (g, Indianapolis, Ind.) Fountain, Montgomery, Parke, Putnam, Counties (ground water) F. A. Watkins (g, Indianapolis, Ind.) Bunker Hill Air Force Base (ground water) F. A. Watkins (g, Indianapolis, Ind.) Iowa: Lower Pennsylvanian floras of Illinois and adjacent States C. B. Read (Albuquerque, N. Mex.) *Stratigraphy of the lead-zinc district near Dubuque J. W. Whitlow (W) *Omaha-Council BluiTs and vicinity, Nebraska and Iowa (urban geology) R. D. Miller (D) *Wisconsin zinc-lead mining district J. W. Whitlow (D) Low-flow frequency studies H. H. Schwob (s, Iowa City, Iowa) Channel geometry studies (surface water) H. H. Schwob (s, Iowa City, Iowa) Flood profiles H. H. Schwob (s, Iowa City, Iowa) Floods from small areas H. H. Schwob (s, Iowa City, Iowa) The Mississippian Aquifer of Iowa W. L. Steinhilber (g, Iowa City, Iowa) Cerro Gordo County (ground water) W. L. Steinhilber (g, Iowa City, Iowa) Linn County (ground water) R. E. Hansen (g, Iowa City, Iowa) Kansas: Trace elements in rocks of Pennsylvanian age, Oklahoma, Kansas, Missouri (uranium, phosphate) W. Danilchik (Quetta, Pakistan) Tri—State lead-zinc district, Oklahoma, Missouri, Kansas E. T. McKnight (W) Paleozoic stratigraphy of the Sedgwick Basin (oil and gas} W. L. Adkison (Lawrence, Kans.) *Shawnee County (oil and gas) W. D. Johnson, Jr. (Lawrence, Kans.) *Wilson County (oil and gas) H. C. Wagner (M) Brown County (ground water) C. K. Bayne (g, Lawrence, Kans.) Cowley County (ground water) C. K. Bayne (g, Lawrence, Kans.) Finney, Kearny, and Hamilton Counties (ground water) S. W. Fader (g, Lawrence, Kans.) Grant and Stanton Counties (ground water) S. W. Fader (g, Lawrence, Kans.) Johnson County (ground water) H. G. O’Connor (g, Lawrence, Kans.) Linn County (ground water) W. J. J ungman (g, Lawrence, Kans.) Miami County (ground water) D. M. Miller (g, Lawrence, Kans.) and Vermillion A—122 GEOLOGICAL Kansas—Continued Montgomery County (ground water) H. G. O’Connor (g, Lawrence, Kans.) Neosho County (ground water) W. J. J‘ungman (g, Lawrence, Kans.) Pratt County (ground water) C. W. Lane (g, Lawrence, Kans.) Rush County (ground water) J. McNellis (g, Lawrence, Kans.) Sedgwick County (ground water) C. W. Lane (g, Lawrence, Kans.) .Trego County (ground water) W. G. Hodson (g, Lawrence, Kans.) Wallace County (ground water) W. G. Hodson (g, Lawrence, Kans.) The efl'ects of sediment characteristics on fluvial mor- phology hydraulics S. A. Schumm (h, D) Southwestern Kansas (ground water) S. W. Fader (g, Lawrence, Kans.) Northwestern Kansas (ground water) S. W. Fader (g, Lawrence, Kans.) Ground water-surface water interrelations L. W. Furness (s, Topeka, Kans.) Flood investigations L. W. Eurness (s, Topeka, Kans.) Sedimentation in the Little Arkansas River basin J. C. Mundorff (q, Lincoln, Nebr.) Fluvial sediment in the Lower Kansas River basin J. C. Mundorff (q, Lincoln, Nebr.) Chemical quality of surface waters and sedimentation in the Saline River drainage basin P. R. Jordan (q, Lincoln, Nebr.) Flood-inundation mapping, Wichita D. W. Ellis (s, Topeka, Kans.) Emergency water supplies in the Wichita area C. W. Lane (g, Lawrence, Kansas) Kentucky: *Geology of the southern Appalachian folded belt, Kentucky, Tennessee and Virginia L. D. Harris (W) ‘Geologic mapping in Kentucky P. W. Richards (Lexington, Ky.) Geologic development of the Ohio River valley L. L. Ray (W) Clay deposits of the Olive Hill bed of eastern Kentucky J. W. Hosterman (W) *Eastern Kentucky coal investigations J. W. Huddle (W) Fluorspar deposits of northwestern Kentucky R. D. Trace (Princeton, Ky.) ‘Salem quadrangle (fluorspar) R. D. Trace (W) Vertebrate paleontology, Big Bone Lick F. C. Whitmore, Jr. (Princeton, Ky.) Mammoth Cave W. E. Davies (W) *Quaternary geology of the Owensboro quadrangle, Ken- tacky-Indiana L. L. Ray (W) Aeromagnetic studies, Middlesboro-Morristown area, Ten- nessee-Kentucky-Virginia R. W. Johnson, Jr. (Knoxville, Tenn.) SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Kentucky—Continued Aerial radiological monitoring surveys. Oak Ridge National Laboratory R. G. Bates (W) Hydrology of large springs in Kentucky T. W. Lambert (g, Louisville, Ky.) Public and industrial water supplies of Kentucky H. T. Hopkins (g, Louisville, Ky.) Geochemistry of natural waters of Kentucky G. E. Hendrickson (g, Louisville, Ky.) Flood-frequency study J. A. McCabe (s, Louisville, Ky.) Bridge-site studies (surface water) C. H. Hannum (s, Louisville, Ky.) Low-flow frequency and flow duration G. A. Kirkpatrick (s, Louisville, Ky.) Drainage-area compilation H. C. Beaber (s, Louisville, Ky.) Rainfall-runoff relations J. A. McCabe (s, Louisville, Ky.) Eastern Kentucky (surface water) G. A. Kirkpatrick (s, Louisville, Ky.) Alluvial terraces of the Ohio River (ground water) W. E. Price (g, Louisville, Ky.) Study of the hydrologic and related effects of strip mining in Beaver Creek watershed J. J. Musser (q, Columbus, Ohio) Jackson Purchase area (ground water) L. M. MacCary (g, Louisville, Ky.) Louisville area (ground water) E. A. Bell (g, Louisville, Ky.) Mammoth Cave area (water resources) G. E. Hendrickson (g, Louisville, Ky.) Louisiana : Public water supplies in Louisiana J. L. Snider (g, Baton Rouge, La.) Southeastern Louisiana (ground water) M. D. Winner (g, Baton Rouge, La.) Southwestern Louisiana (ground water) A. H. Harder (g, Baton Rouge, La.) Flood investigations L. V. Page (s, Baton Rouge, La.) Ponds as runoff measuring devices R. Sloss (s, Baton Rouge, La.) Bossier and Caddo Parishes (ground water) H. C. May (g, Baton Rouge, La.) East and West Feliciana Parishes (ground water) C. 0. Morgan (g, Baton Rouge, La.) Natchitoches Parish (ground water) R. Newcome (g, Baton Rouge, La.) Rapides Parish (ground water) R. Newcome (g, Baton Rouge, La.) Red River Parish (ground water) R. N ewcome (g, Baton Rouge, La.) Sabine Parish (ground water) R. Newcome (g, Baton Rouge, La.) Vernon Parish (ground water) J. E. Rogers (g, Baton Rouge, La.) Baton Rouge-New Orleans valley area (ground water) G. T. Cardwell (g, Baton Rouge, La.) Baton Rouge area (ground water) 0. 0. Morgan (g, Baton Rouge, La.) Trap efliciency of reservoir on Bayou Dupont watershed S. F. Kapustka (q, Baton Rouge, La.) REGIONAL INVESTIGATIONS IN PROGRESS Louisiana—Continued Ouachita River basin (quality of surface waters) D. E. Everette (q, Baton Rouge, La.) Tallulah area (ground water) A. N. Turcan, Jr. (g, Baton Rouge, La.) Maine: *Attean quadrangle A. L. Albee (Pasadena, Calif.) *Bedrock geology of the Danforth, Forest, and Vanceboro quadrangles D. M. Larrabee (W) ‘Greenville quadrangle G. H. Espenshade (W) 'The Forks quadrangle F. C. Canney and E. V. Post (D) ‘Southeastern Aroostook County (manganese) L. Pavlides (W) Aeromagnetic surveys J. W. Allingham (W) Gravity studies, northern Maine M. F. Kane (W) *Electromagnetic and geologic mapping in Island Falls quadrangle F. C. Frischknecht (D) *Geophysical and geologic mapping in the Stratton quad- rangle A. Griscom (W) Coastal area of southwestern Maine (ground water) G. C. Prescott (g, Augusta, Maine) Maryland: ‘Potomac Basin studies, Maryland, Virginia, and West Virginia J. T. Hack (W) Clay deposits M. M. Knechtel (W) ‘Allegany County (coal) W. de Witt, Jr. (W) Aerial radiological monitoring surveys, Belvoir area, Vir- ginia and Maryland S. K. Neuschel (W) ‘Correlation of aeromagnetic studies and areal geology, Montgomery County A. Griscom (W) Airborne radioactivity and environmental studies, Wash- ington County R. M. Moxham (W) Low-flow analyses J. W. Odell ( (s, College Park, Md.) Effect of urbanization on peak discharge R. W. Carter (s, W) Changes below dams ‘M. G. Wolman (h, Baltimore, Md.) Laboratory study of the growth of meanders in open channels M. G. Wolman (h, Baltimore, Md.) Potomac River basin P. M. Johnston (g, W) Allegany and Washington Counties (ground water) T. H. Slaughter (g, Baltimore, Md.) Anne Arundel County (ground water) F. K. Mack (g, Baltimore, Md.) Charles County (ground water) T. H. Slaughter (g, Baltimore, Md.) A—123 Maryland—Continued Northern and western Montgomery County (ground water) P. M. Johnston (g, Baltimore, Md.) Fort George G. Meade (ground water) E. G. Otton (g, Baltimore, Md.) Sharpsburg area (ground water) E. G. Otton (g, Baltimore, Md.) Massachusetts : Research and application of geology and seismology to Public Works planning L. R. Page (Boston, Mass.) Central Cape Cod, subsurface studies L. W. Currier (W) Sea-cliff erosion studies C. A. Kaye (Boston, Mass.) *Stratigraphy and structure of Taconic rocks E-an Zen (W) Vertebrate faunas, Martha’s Vineyard F. C. Whitmore, Jr. (W) *Assawompsett Pond quadrangle C. Koteff (Boston, Mass.) *Athol quadrangle D. F. Eschman (Ann Arbor, Mich.) *Ayer quadrangle; bedrock geologic mapping R. H. J ahns (University Park, Pa.) *Billerica, Lowell, Tyngsboro, and Westford quadrangles R. H. J ahns (University Park, Pa.) 'Blue Hills quadrangle N. E. Chute (Syracuse, NY.) *Clinton and Shrewsbury quadrangles; bedrock geologic mapping R. F. Novotny (Boston, Mass.) *Concord and Georgetown quadrangles N. P. Cuppels (Boston, Mass.) *Duxbury and Scituate quadrangles, mapping N. E. Chute (Syracuse, NY.) *Greenfield quadrangle; surficial geologic mapping R. H. J ahns (University Park, Pa.) ‘Lawrence, Reading, South Groveland, and Wilmington quadrangles ; bedrock geologic mapping R. 0. Castle (Los Angeles, Calif.) *North Adams quadrangle; bedrock geologic mapping N. Herz (Belo Horizonte, Brazil) *Norwood quadrangle N. E. Chute (Syracuse, N .Y.) ‘Reading and Salem quadrangles; surficial geologic mapping R. N. Oldale (Boston, Mass.) *Salem quadrangle; bedrock geologic mapping P. Toulmin, III (W) ‘Springfield south quadrangle J. H. Hartshorn and C. Kotoff (Boston, Mass.) *Taunton quadrangle; surficial geologic mapping J. H. Hartshorn (Boston, Mass.) Low-flow characteristics G. K. Wood (s, Boston, Mass.) Southeastern Massachusetts (ground water) 0. M. Hackett (g, Boston, Mass.) Western Massachusetts (ground water) 0. M. Hackett (g, Boston, Mass.) Southern Plymouth County (ground water) J. M. Weigle (g, Boston, Mass.) Brockton-Pembroke area (ground water) R. G. Petersen (g, Boston, Mass.) surficial geologic A—124 Massachusetts—Continued Cadwell Brook, Massachusetts (surface water) G. K. Wood (s, Boston, Mass.) Analysis of surface water-ground water relationships in Hop Brook Basin J. C. Kammerer (h, Boston, Mass.) Ipswich River drainage basin (ground water) J. A. Baker (g, Boston, Mass.) Lowell area (ground water) 0. M. Hackett (g, Boston, Mass.) Lower Merrimack valley (ground water) J. A. Baker (g, Boston, Mass.) Parker and Rowley River drainage basins (ground water) J. A. Baker (g, Boston, Mass.) Wilmington-Reading area (ground water) 0. M. Hackett (g, Boston, Mass.) Michigan: Geology of the Michigan Basin with reference to disposal of high-level radioactive wastes W. deWitt (W) *Lake Algonquin drainage J. T. Hack (W) *Michigan copper district W. S. White (W) *Southern Dickinson County (iron) R. W. Bayley (M) *Eastern Iron County (iron) K. L. Wier (Iron Mountain, Mich.) ‘East Marquette district (iron) J. E. Gair (D) *Iron River-Crystal Falls district (iron) H. L. James (M) Geophysical studies in the Lake Superior region. G. D. Bath (M) Areal low-flow study R. L. Knutilla and J. B. Miller (s, Lansing, Mich.) Alger County (ground water) K. S. Vanlier (g, Lansing, Mich.) Battle Creek area (ground water) M. Deutsch (g, Lansing, Mich.) North Branch Clinton River basin (surface water) S. W. Wiitala (s, Lansing, Mich.) Elsie area (ground water) K. E. Vanlier (g, Lansing, Mich.) Artificial recharge at Kalamazoo J. E. Reed (g, Lansing, Mich.) Rifle River basin, Michigan (surface water) R. W. Larson (s, Grayling, Mich.) Sloan and Deer Creek basins (surface water) L. E. Stoimenoff (s, Lansing, Mich.) Minnesota: *Cuyuna North range (iron) R. G. Schmidt (W) Geophysical studies in the Lake Superior region G. D. Bath (M) Flood-frequency analysis C. H. Prior (5, St. Paul, Minn.) Clay County (ground water) R. H. Brown (g, St. Paul, Minn.) Kittson, Marshall, and Roseau Counties (ground water) G. R. Schiner (g, St. Paul, Minn.) Nobles County and part of Jackson County (ground water) R. F. Norvitch (g, St. Paul. Minn.) GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF‘ RESULTS Minnesota—Continued Water resources in the vicinity of municipalities in the Mesabi Range area R. D. Cotter (g, St. Paul, Minn.) Bedrock topography of the eastern Mesabi Range area, St. Louis County E. L. Oakes (g, St. Paul, Minn.) Aurora area (ground water) R. W. Maclay (g, St. Paul, Minn.) Chisholm area and Balkan Township, St. Louis County (ground water) R. F. Norvitch (g, St. Paul, Minn.) Duluth Air Force Base (ground water) J. E. Rogers (g, St. Paul, Minn.) Hibbing area (ground water) R. F. Norvitch (g, St. Paul, Minn.) Mountain Iron-Virginia area (ground water) R. D. Cotter (g, St. Paul, Minn.) Redwood Falls area (ground water) G. R. Schiner (g, St. Paul, Minn.) Mississippi : Oligocene gastropods and pelecypods F. S. MacNeil (M) Mesozoic rocks of Florida and eastern Gulf Coast P. L. Applin (Jackson, Miss.) Pre—Selma Cretaceous rocks of Alabama and adjacent States L. C. Conant (Tripoli, Libya) Geologic and hydrologic environment of Tatum salt dome (test-site evaluation) W. S. Twenhofel (D) Drainage area determination J. D. Shell (s, Jackson, Miss.) Flood-frequency analysis K. V. Wilson (s, Jackson, Miss.) Floods from small basins K. V. Wilson (5, Jackson, Miss.) Bridge-site studies (surface water) K. V. Wilson (s, Jackson, Miss.) Low—flow characteristics H. G. Golden (s, Jackson, Miss.) Salt-water encroachment along the Mississippi Gulf Coast J. W. Lang (g, Jackson, Miss.) Southwestern Mississippi (water resources) E. J. Harvey (g, Jackson, Miss.) Cretaceous aquifers in MissiSSippi J. W. Lang (g, Jackson, Miss.) Delta area (ground water) B. E. Wasson (g, Jackson, Miss.) Jackson area (ground water) E. J. Harvey (g, Jackson, Miss.) Pascagoula River basin (ground water) E. J. Harvey (g, Jackson, Miss.) Pearl River basin (ground water) B. E. Ellison (g, Jackson, Miss.) Missouri: *Lead deposits of southeastern Missouri T. H. Kiilsgaard (W) Tri—State lead-zinc district, Oklahoma, Missouri, Kansas E. T. McKnight (W) Trace elements in rocks of Pennsylvanian age, Oklahoma, Kansas, Missouri (uranium, phosphate) W. Danilchik (Quetta, Pakistan) REGIONAL INVESTIGATIONS IN PROGRESS Missouri—Continued Aeromagnetic studies in the Newport, Arkansas, and Ozark bauxite areas A. Jesperson (W) Correlation of aeromagnetic studies and areal geology, southeast Missouri J. W. Allingham (W) 0 Flood investigations in small areas ’ E. H. Sandhaus (s, Rolla, Mo.) Transportation of sediment by the Mississippi River P. R. Jordan (q, Lincoln, Nebr.) Montana: General geology: ‘ Chemical and physical properties of the Pierre shale, Mon- tana, North Dakota, South Dakota, Wyoming, and Nebraska H. A. Tourtelot (D) Carbonatite deposits W. T. Pecora (W) Mesozoic stratigraphic Montana W. A. Cobban (D) *Alice Dome—Sumatra area H. R. Smith (D) *Petrology of the Bearpaw Mountains .W. T. Pecora (W) *Geochemistry and metamorphism of the Belt Series; Clark Fork and Packsaddle Mountain quadrangles, Idaho and Montana J. E. Harrison (D) *Big Sandy Creek area R. M. Lindvall (D) *Quaternary geology of the Browning area and the east slope of Glacier National Park G. M. Richmond (D) *Duck Creek Pass quadrangle W. H. Nelson (D) *South Gallatin Range 1. J. Witkind (D) *Gravelly Range-Madison Range J. B. Hadley (D) Earthquake investigations, Hebgen Lake J. B. Hadley (W) and I. J. Witkind (D) *Maudlow quadrangle B. Skipp (D) Petrology and chromite resources—of the Stillwater ultra- mafic complex E. D. Jackson (MK) *Sun River Canyon area M. R. Mudge (D) *Three Forks quadrangle G. D. Robinson (D) *Toston quadrangle G. D. Robinson (D) ‘Willis quadrangle W. B. Myers (D) *Petrology of the Wolf Creek area B. G. Schmidt (W) Mineral resources: Ore deposits of southwestern Montana H. L. James (M) Phosphate deposits of south-central Montana R. W. Swanson (Spokane, Wash.) paleontology of northwestern A—125 Montana—Continued Mineral resources—Continued *Boulder batholith area (base, precious, and radioactive metals) M. R. Klepper (W) *General geology of the Coeur d’Alene mining district (lead, zinc, silver) A. B. Griggs (M) Ore deposits of the Coeur d’Alene mining district (lead, zinc, silver) V. C. Fryklund, Jr. (Spokane, Wash.) Manganese deposits of the Philipsburg area (manganese and base metals) W. C. Prinz (W) *Thunder Mountain niobium area, Montana-Idaho R. L. Parker (D) Williston Basin oil and gas studies, Wyom‘ing, Montana, North Dakota, and South Dakota C. A. Sandberg (D) *Geology of the Winnett—Mosby area (oil and gas) W. D. Johnson, Jr. (Lawrence, Kans.) *Geology of the Livingston-Trail Creek area (coal) A. E. Roberts (D) Engineering geology: Geology of the Williston Basin with reference to the dis- posal of high-level radioactive wastes C. A. Sandberg (D) *Fort Peck area (construction-site planning) H. D. Varnes (D) *Great Falls area, Montana (urban geology and construction- ‘site planning) R. W. Lemke (D) *Wolf Point area (construction-site planning) R. B. Colton (D) Geophysical studies: Pacific Northwest geophysical studies W. E. Davis (W) Magnetic studies of Montana laccoliths R. G. Henderson (W) Gravity and magnetic studies .in western Montana W. T. Kinoshita (M) Correlation of aeromagnetic studies and areal geology, Bearpaw Mountains K. G. Books (W) Aeromagnetic and gravity studies of the Boulder batholith W. E. Davis (M) Gravity studies, Yellowstone area H. L. Baldwin (D) Water resources: Natural flow appraisals (water) W. A. Blenkarn (5, Helena, Mont.) Floods from small areas F. C. Boner (s, Helena, Mont.) Study of water application and use on a range water spreader in northeast Montana F. A. Branson (h, D) Bitterroot Valley, Ravalli County (ground water) R. G. McMurtery (g, Billings, Mont.) Lower Bighorn River valley (Hardin Unit) water) L. J. Hamilton (g, Billings, Mont.) Northeastern Blaine County (ground water) E. A. Zimmerman (g, Billings, Mont.) (ground A—126 Montana—Continued Water resources—Continued Blue Water Springs area (ground water) F. A. Swenson (g, Billings, Mont.) Deer Lodge Valley (ground water) R. L. Konizeski (g, Billings, Mont.) Fort Belknap Indian Reservation (ground water) D. C. Alverson (g. Billings, Mont.) Southern part of the Judith Basin (ground water) E. A. Zimmerman (g, Billings, Mont.) Milk River bottoms, Fort Belknap area (ground water) W. B. Hopkins (g, Billings, Mont.) Two Medicine Irrigation project (ground water) Q. F. Paulso-n (g, Billings, Mont.) Nebraska: Chemical and physical properties of the Pierre shale, Montana, North Dakota, South Dakota, Wyom- ing, and Nebraska H. A. Tourtelot (D) *Lower Republican River R. D. Miller (D) *Valley County R. D. Miller (D) Subsurface geology of Dakota sandstone, Colorado and Nebraska (oil and gas) N. W. Bass (D) Central Nebraska basin (oil and gas) G. E. Prichard (D) Omaha-Council Bluffs and vicinity, Nebraska and Iowa (urban geology) R. D. Miller (D) Peak discharges from small areas E. W. Beckman (s, Lincoln, Nebr.) Bridge-site studies (surface water) E. \V. Beckman (s, Lincoln, Nebr.) Evapotranspiration study 0. E. Leppanen (h, Phoenix, Ariz.) Channel patterns and terraces of the Loup Rivers J. C. Brice ((1, Lincoln, Nebr.) Trap efficiencies of reservoir 1 and 1A, Brownell Creek Subwatershed J. C. Mundorff (q, Lincoln, Nebr.) Fillmore County (ground water) 0. F. Keech (g, Lincoln, Nebr.) Hamilton County (ground water) C. F. Keech (g, Lincoln, Nebr.) York County (ground water) C. F. Keech (g, Lincoln, Nebr.) Erosion and deposition in Medicine Creek basin J. C. Brice (q, Lincoln, Nebr.) Ground water near the Platte River south of Chapman C. F. Keech (g, Lincoln, Nebr.) Cedar River valley in the lower Platte River basin (ground water) J. B. Hyland (g, Lincoln, Nebr.) Upper Salt Creek drainage basin (ground water) C. F. Keech (g, Lincoln, Nebr.) Nevada: General geology: Fusuline Foraminifera of Nevada R. C. Douglass (W) *Ash Meadows quadrangle, California-Nevada C. S. Denny (W) GEOLOGICAL SURVEY RESEARCH lQGl—SYNOPSIS OF RESULTS NevadawContinued General geology-Continued *Cortez quadrangle J. Gilluly (D) "Esmeralda County J. P. Albers (M) *Fallon area B. B. Morrison (D) *Frenchie Creek quadrangle L. J. P. Muflier (D) *Horse Creek Valley quadrangle H. Masursky (D) "Humboldt County C. R. Willden (M) Lower Mesozoic stratigraphy and paleontology, boldt Range N. J. Silberling (M) *Jarbidge area R. R. Coats (M) *Kobeh Valley C. W. Merriam (W) *Las Vegas—Lake Mead area 0. R. Longwell (M) MLincoln County 0. M. Tschanz (M) "Mineral County D. C. Ross (M) *Mt. Lewis and Crescent Valley quadrangles J. Gilluly (D) "Northern Nye County F. J. Kleinhampl (M) *Owyhee and Mt. City quadrangles, Nevada-Idaho R. R. Coats (M) “Pershing County D. B. Tatlock (M) *Railroad District, and the Dixie Flats, Pine Valley, and Robinson Mountain quadrangles J. F. Smith, Jr. (D) ‘Schell Creek Range H. D. Drewes (D) Mineral resources: Geochemical halos of mineral deposits, Utah and Nevada R. L. Erickson (D) Iron ore deposits R. G. Reeves (M) Origin of the boratebearing marsh deposits of Cali- fornia, Oregon, and Nevada (boron) W. C. Smith (M) Stratigraphy and resources of the Phosphoria and Park City formations in Utah and Nevada (phosphate, minor elements) K. M. Tagg (M) \Vestern oxidized zinc deposits A. V. Heyl (W) *Antler Peak quadrangle (base and precious metals) R. J. Roberts (M) ‘Beatty area (fluorite, bentonite, gold, silver) H. R. Cornwall (M) *Regional geologic setting of the Ely district (copper, lead, zinc) A. L. Brokaw (D) ‘Eureka area (zinc, lead, silver, gold) T. B. Nolan (W) Hum- REGIONAL INVESTIGATIONS IN PROGRESS Nevada——Continued Mineral resources—Continued "Eureka County (base and precious metals) R. J. Roberts (M) Ione quadrangle (lead, quicksilver, tungsten) C. J. Vitaliano (Bloomington, Ind.) *Lyon, Douglas, and Ormsby Counties (copper) J. G. Moore (M) *Osgood Mountains quadrangle (tungsten, quicksilver) P. E. Hotz (M) *Unionville and Buffalo Mountain quadrangles, Humboldt Range (iron, tungsten, silver, quicksilver) R. E. Wallace (M) *Wheeler Peak and Garrison quadrangles, (tungsten, beryllium) D. H. Whitebread (M) Engineering geology and geophysical studies: Great Basin geophysical studies D. R. Mabey (M) Gravity studies, California-Nevada region D. J. Stuart (D) ‘Geologic and hydrologic environment, Nevada Test Site F. A. McKeown (D) *Engineering geology of the Nevada Test Site area V. R. Wilmarth (D) Geophysical studies of Nevada Test Site R. A. Black .(D) Aerial radiological monitoring surveys, Nevada Test Site J. L. Meuschke (W) Water resources: Statewide reconnaissance of ground—water basins ‘T. E. Eakin (g, Carson City, Nev.) Northwestern basins (ground water) W. C. Sinclair (g, Carson City, Nev.) Fernley-Wadsworth area (ground water) W. C. Sinclair (g, Carson City, Nev.) Hydrology of a portion of the Humboldt River Valley T. \V. Robinson (h, M) Kings River valley (ground water) C. P. Zones (g, Carson City, Nev.) Las Vegas basin (ground water) G. T. Malmberg (g, Carson City, Nev.) Nevada Test Site (ground water) ‘ S. L. Schoff (g, D) Pahrump Valley (ground water) G. T. Malmberg (g, Carson City, Nev.) Truckee Meadows (ground water) 0. J. Loeltz (g, Carson City, Nev.) New Hampshire: Correlation of aeromagnetic studies and areal geology, New Hampshire and Vermont R. W. Bromery (W) Seacoast region (ground water) J. M. Weigle (g, Boston, Mass.) New Jersey: *Lower Delaware River basin, New Jersey-Pennsylvania J. P. Owens (W) ‘Middle Delaware River Basin, New Jersey-Pennsylvania A. A. Drake, Jr. (W) *Selected iron deposits of the Northeastern States A. F. Buddington (Princeton, N.J.) Correlation of aeromagnetic studies and areal geology, New York-New Jersey Highlands (iron) A. Jesperson (W) Snake Range A—127 New J ersey—Continued Chloride in the ground water of New Jersey P. R. Seaber (g, Trenton, N.J.) Geochemistry of ground water in the Englishtown formation P. R. Seaber (g, Trenton, N.J.) Geologic and hydrologic reconnaissance of potential reactor sites H. E. Gill (g, Trenton, N.J.) Flood-frequency analysis R. H. Tice (s, Trenton, N.J.) Flood and base-flow gaging E. G. Miller (s, Trenton, N.J.) Flood-plain zoning R. H. Tice (s, Trenton, N.J.) Flow duration (surface water) E. G. Miller (s, Trenton, N.J.) Hydrology and sedimentation of Stony Brook basin J. R. George (q, Harrisburg, Pa.) Burlington County (ground water) F. E. Rush (g, Trenton, N.J.) Camden County (ground water) E. Donsky (g, Trenton, N.J.) Essex County (ground water) J. Vecchioli (g, Trenton, N.J.) Gloucester County (ground water) W. F. Hardt (g, Trenton, N.J.) Mercer County (ground water) J. Vecchioli (g, Trenton, N.J.) Monmouth County (ground water) L. A. Jablonski (g, Trenton, N.J.) Morris County (ground water) H. E. Gill (g, Trenton, N.J.) Ocean County (ground water) C. A. Appel (g, Trenton, N.J.) Salem County (ground water) J. C. Rosenau (g, Trenton, N.J.) Passaic Valley (ground water) J. Vecchioli (g, Trenton, N .J .) Phillipsburg area (ground water) J. G. Randolph (g, Trenton, N.J.) Pine Barrens (ground water) E. C. Rhodehamel (g, Trenton, N.J.) Rahway area (ground water) H. R. Anderson (g, Trenton, N.J.) Sayreville area (ground water) C. A. Appel (g, Trenton, N.J.) Wharton Tract (ground water) E. C. Rhodehamel (g, Trenton, N.J.) New Mexico: General geology: New Mexico geologic map 0. H. Dane (W) Stratigraphic significance of the genus Tempskya in south- western New Mexico C .B. Read (Albuquerque, N. Mex.) Diatremes, Navajo and Hopi Indian Reservations E. M. Shoemaker (M) "Cedar Mountain and Southern Peloncillo Mountains areas C. S. Bromfield (D) *Upper Gila River basin, Arizona—New Mexico R. B. Morrison (D) Guadelupe Mountains P. T. Hayes (D) A—128 New Mexico—Continued General geology—Continued *Southern Oscura, northern San Andres Mountains G. O. Bachman (D) ‘Philmont Ranch quadrangle G. D. Robinson (D) *Petrology of the Valles Mountains R. L. Smith (W) Mineral resources: "Compilation of Colorado Plateau geologic maps (uranium, vanadium) D. G. Wyant (D) Colorado Plateau botanical prospecting studies F. J'. Kleinhampl (M) Uranium-vanadium deposits in sandstone, with emphasis on the Colorado Plateau R. P. Fischer (D) Relative concentrations of chemical elements in different rocks and ore deposits of the Colorado Plateau (uranium, vanadium, copper) A. T. Miesch (D) Clay studies, Colorado Plateau L. G. Schultz (D) Lithologic studies, Colorado Plateau R. A. Cadigan (D) Stratigraphic studies, Colorado Plateau (uranium, vana- dium) L. C. Craig (D) Triassic stratigraphy and lithology of the Colorado Plateau (uranium, copper) J. H. Stewart (D) San Rafael group stratigraphy, Colorado Plateau(uranium) J. C. Wright (D) Regional relationship of the uranium deposits of north- western New Mexico L. S. Hilpert (Salt Lake City, Utah) Ambrosia Lake district (uranium) H. C. Granger (D) *Carrizo Mountains area, Arizona-New Mexico (uranium) J. D. Strobell (D) *Grants area (uranium) R. E. Thaden (Columbia, Ky.) Mineralogy of uranium-bearing rocks in the Grants area A. D. Weeks (W) *Laguna district (uranium) R. H. Moench (D) "Tucumcari-Sabinoso area (uranium) R. L. Griggs (D) *Silver City region (copper, zinc) W. R. Jones (D) Potash and other saline deposits of the Carlsbad area 0. L. Jones (M) Oil and gas fields D. C. Duncan (W) *Franklin Mountains, New Mexico and Texas (petroleum) R. L. Harbour (D) *Animas River area, Colorado and New Mexico (coal, oil, and gas) H. Barnes (D) *Raton Basin coking coal G. H. Dixon (M) *East side San Juan Basin (coal, oil, gas) C. H. Dane (W) GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS New Mexico—Continued Engineering geology and geophysical studies: *Engineering geology of Gnome Test Site L. M. Gard (D) *Nash Draw quadrangle (test-site evaluation) J. D. Vine (M) Colorado Plateau regional geophysical studies H. R. Joesting (W) Geophysical studies in the Rowe-Mora area G. E. Andreasen (W) Water resources: Hydrologic almanac of New Mexico W. E. Hale (g, Albuquerque, N. Mex.) Use of water by municipalities in New Mexico G. A. Dinwiddie (g, Albuquerque, N. Mex.) Recharge studies on the High Plains J. S. Havens (g, Albuquerque, N. Mex.) Maps showing quality of water by Counties F. D. Trauger (g, Albuquerque, N. Mex.) Flood gaging and bridge-site studies L. A. Wiard (s, Santa Fe, N. Mex.) Flood—frequency relations L. A. Wiard (s, Santa Fe, N. Mex.) The effects of exposure on slope morphology R. F. Hadley (h, D) The eflfects of sediment characteristics on fluvial morphol- ogy hydraulics S. A. Schumm (h, D) Sediment transport parameters in sand bed streams J. K. Culbertson (g, Albuquerque, N. Mex.) Use of tritium in hydrologic studies C. W. Carlston (g, W) Acoma and Laguna Indian Reservations (ground water) J. E. Weir (g, Albuquerque, N. Mex.) Albuquerque area (ground water) L. J. Bjorklund (g, Albuquerque, N. Mex.) Canoncito School facility (ground water) B. W. Maxwell (g, Albuquerque, N. Mex.) Carlsbad area (ground water) L. J. Bjorklund (g, Albuquerque, N. Mex.) Study of precipitation runoff and sediment yield in Corn- field Wash D. E. Burkham (h, Albuquerque, N. Mex.) Test drilling at El Morro National Monument S. W. West (g, Albuquerque, N. Mex.) Gallup area (ground water) S. W. West (g, Albuquerque, N. Mex.) Ground water studies in conjunction with project Gnome, Eddy County J. B. Cooper (g, Albuquerque, N. Mex.) Grant County (ground water) F. D. Trauger (g, Albuquerque, N. Mex.) Guadalupe County (ground water) A. Clebsch (g, Albuquerque, N. Mex.) Hondo Valley (ground water) W. A. Mourant (g, Albuquerque, N. Mex.) Tritium as a tracer in the Lake McMillan underground reservoir H. O. Reeder (g, Albuquerque, N. Mex.) Tritium as a tracer in the Ogallala formation in the High Plains, Lea County H. O. Reeder (g, Albuquerque, N. Mex.) Northern Lea County (ground water) H. O. Reeder (g, Albuquerque, N. Mex.) REGIONAL INVESTIGATIONS IN PROGRESS New Mexico—Continued Water resources—Continued Southern Lea County (ground water) A. Clebsch (g, Albuquerque, N. Mex.) Southern Luna County (ground water) G. C. Doty (g, Albuquerque, N. Mex.) Southeastern McKinley County (ground water) J. B. Cooper (g, Albuquerque, N. Mex.) McMillan delta area (ground water) E. R. Cox (g, Albuquerque, N. Mex.) Southern Jicarilla Indian Reservation (ground water) S. W. West (g, Albuquerque, N. Mex.) Ground-water conditions between Lake McMillan and Carls- bad Springs E. R. Cox (g( Albuquerque, N. Mex.) Los Alamos area (ground water) R. L. Cushman (g, Albuquerque, N. Mex.) Evaluation of well-field data at Los Alamos R. L. Cushman (g, Albuquerque, N. Mex.) Waste contamination studies at Los Alamos (ground water) J. H. Abrahams (g, Albuquerque, N. Mex.) Mortandad Canyon (ground water) J. E. Weir (g, Albuquerque, N. Mex.) Quay County (ground water) F. D. Trauger (g, Albuquerque, N. Mex.) Feasibility of Queen Lake as a disposal area for brine E. R. Cox (g, Albuquerque, N. Mex.) Rio Grande Valley near Hot Springs (ground water) E. R. Cox (g, Albuquerque, N. Mex.) Ground-water pumpage in the Roswell Basin R. M. Mower (g, Albuquerque, N. Mex.) Ground-water recharge in the Roswell Basin W. S. Motts (g, Albuquerque, N. Mex.) Roswell Basin water salvage R. W. Mower (g, Albuquerque, N. Mex.) Tritium in ground water in the Roswell Basin J . W. Hood (g, Albuquerque, N. Mex.) Sandia and Manzano Mountains area (ground water) F. B. Titus (g, Albuquerque, N. Mex.) Northern San Juan County (ground water) F. D. Trauger (g, Albuquerque, N. Mex.) Particle movement and channel scour and fill of an ephemeral arroya near Santa Fe L. B. Leopold (w, W) Three Rivers area (ground water) J. W. Hood (g, Albuquerque, N. Mex.) Ground water in structural basins west of Tucumcari F. D. Trauger (g, Albuquerque, N. Mex.) Eastern Valencia County (ground water) F. B. Titus (g, Albuquerque, N. Mex.) Northern White Sands Integrated Range (ground water) J. E. Weir (g, Albuquerque, N. Mex.) Zia, San Ildefonso, and Acoma Indian reservations (ground water) J. R. Rapp (g, Albuquerque, \N. Mex.) New York : *Glacial geology of the Elmira-Williamsport area, New York-Pennsylvania C. S. Denny (W) ‘Stratigraphy and structure of Taconic rocks E-an Zen (W) *Selected iron deposits of the Northeastern States A. F. Buddington (Princeton, N .J .) A—129 New York—Continued Metamorphism and origin of mineral deposits, Gouverneur area A. E. J. Engel (Pasadena, Calif.) *Richville quadrangle H. M. Bannerman (W) Stratigraphy of the Dunkirk and related beds (oil and gas) W. de Witt, Jr. (W) *Stratigraphy of the Dunkirk and related beds, in the Bath and Woodhull quadrangles (oil and gas) J. F. Pepper (New Philadelphia, Ohio) *Stratigraphy of the Dunkirk and related beds in the Penn Yan and Keuka Lake quadrangles (oil and gas) M. J. Bergin (W) Correlation of aeromagnetic studies and areal geology. Adirondacks area (iron) J. R. Balsley (W) Correlation of aeromagnetic studies and areal geology, New York—New Jersey Highlands (iron) A. Jespersen (W) Recognition of late glacial substages in New England and New York J. E. Upson (g, Mineola, N .Y.) Experimental recharge basin (surface water) R. M. Sawyer (s, Albany, N.Y.) Low-flow analyses B. Dunn (s, Albany, N .Y.) Small streams (surface water) 0. P. Hunt (s, Albany, N.Y.) Delaware County (ground water) J. Soren (g, Albany, N.Y.) Northeast Nassau County (ground water) J. Isbister (g, Albany, N.Y.) Salt-water encroachment in southern Nassau County N. J. Lusczynski (g, Albany, N.Y.) Cadmium-chromium contamination in ground water in Nas- sau County N. J. Lusczynski (g, Albany, N.Y.) Orange and Ulster Counties (ground water) R. D. Duryea (g, Albany, N .Y.) Queens County (ground water) N. M. Perlmutter (g, Albany, N.Y.) Schodack terrace, Rensselaer County (ground water) J. Joyce (g, Albany, N.Y.) Flood and low-flow gaging, Rockland County G. R. Ayer (s, Albany, N .Y.) Saratoga County (ground water) R. C. Heath (g, Albany, N.Y.) Eastern Schenectady County (ground water) J. D. Winslow (g, Albany, N.Y.) Mid-island area, western Suffolk County (ground water) N. M. Perlmutter (g, Albany, N.Y.) Babylon—Islip area, Suffolk County (ground water) I. H. Kantrowitz (g, Albany, N .Y.) Babylon-Islip area (surface water) E. J. PluhoWski (s, Albany, N.Y.) Chemical and physical quality of water resources in the Housatonic River basin E. H. Salvas (q, Albany, N.Y.) Jamestown area (ground water) R. A. Wilkens (g, Albany, N.Y.) Montauk Air Force Station (ground water) N. M. Perlmutter (g, Albany, N.Y.) A—130 New York—Continued Niagara Frontier (ground water) R. H. Johnston (g, Albany, N.Y.) St. Lawrence River basin (chemical and physical quality of water resources) A. L. Mattingly (q, Albany, NY.) Syracuse area (ground water) J. A. Tannenbaum (g, Albany, N.Y.) West Milton well field J. D. Winslow (g, Albany, N.Y.) North Carolina : *Great Smoky Mountains, Tennessee and North Carolina J. B. Hadley (D) *Central Piedmont H. Bell (W) *Grandfather Mountain B. H. Bryant (D) *Investigations of the Volcanic Slate series A. A. Stromquist (D) Massive sulfide deposits of the Ducktown district, Tennessee and adjacent areas (copper, iron, sulfur) R. M. Hernon (D) *Swain County copper district G. H. Espenshade (W) *Shelby quadrangle (monazite) W. C. Overstreet (W) Pegmatites of the Spruce Pine and Franklin-Sylva districts F. G. Lesure (Knoxville, Tenn.) *Geologic setting of the Spruce Pine pegmatite district (mica, feldspar) D. A. Brobst (D) *Hamme tungsten deposit J. M. Parker, III (Raleigh, N.C.) Central and western North Carolina regional aeromagnetic survey R. W'. Johnson, Jr. (Knoxville, Tenn.) Aeromagnetic studies, Concord-Denton area R. W. Johnson, Jr. (Knoxville, Tenn.) Flood gaging H. G. Hinson (s, Raleigh, N.C.) Flood-frequency studies H. G. Hinson (s, Raleigh, N.C.) ‘ Interpretation of data (surface water) G. C. Goddard (s, Raleigh, N.C.) Stream sanitation and water supply G. C. Goddard (s, Raleigh, N.C.) Salt-water intrusion in coastal streams J. C. Chemerys (q, Raleigh, N.C.) Chemical characteristics of public water supplies K. F. Harris (q, Raleigh, N.C.) Diagenesis and hydrologic history of the Tertiary limestone of North Carolina H. E. LeGrand (w, W) Stratigraphy of the Trent marl and related units P. M. Brown (g, Raleigh, N.C.) Ashe and Watauga Counties (quality of water resources) H. B. Wilder (q, Raleigh, N.C.) Martin County (ground water) G. G. Wyrick (g, Raleigh, N.C.) Blue Ridge Parkway construction sites (ground water) J. O. Kimrey (g, Raleigh, N.C.) Cape Hatteras National Park (quality of ground water) K. F. Harris (q, Raleigh, N.C.) \ GEOLOGICAL SURVEY RESEARCH 1961—SYN‘OPSIS OF RESULTS North Carolina—Continued Cumberland Gap National Historical Park (ground water) J. O. Kimrey (g, Raleigh, N.C.) Dare Beaches Sanitary District (ground water) J. 0. Kimrey (g, Raleigh, N .0.) Monroe area (ground water) E. 0. Floyd (g, Raleigh, N.C.) Plymouth area (ground water) H. Peek (g, Raleigh, N.C.) Southport area (ground water) P. M. Brown (g, Raleigh, N.C.) North Dakota: Chemical and physical properties of the Pierre shale, Montana, North Dakota, South Dakota, Wyoming, and Nebraska H. A. Tourtelot (D) Williston Basin oil and gas studies, Wyoming, Montana, North Dakota, and South Dakota C. A. Sandberg (D) Geology of the Williston Basin with reference to the dis- posal of high-level radioactive wastes C. A. Sandberg (D) Peak discharges from small areas 0. A. Crosby (s, Bismarck, N. Dak.) Hyd ology of prairie potholes J. .Shejeflo (h, D) Glacial valleys in Divide, Williams, and McKenzie Counties (ground water) E. Bradley (g, Grand Forks, N. Dak.) Kidder County (ground water) E. Bradley (g, Grand Forks, N. Dak.) Stutsman County (ground water) C. J. HuXel (g, Grand Forks, N. Dak.) Traill County (ground water) H. M. Jensen (g, Grand Forks, N. Dak.) Bowbells area (ground water) H. M. Jensen (g, Grand Forks, N. Dak.) Cheyenne and Standing Rock Indian Reservations (ground water) J. E. Powell (g, Huron, 'S. Dak.) Devils Lake area (ground water) P. D. Akin (g, Grand Forks, N. Dak.) Chemical quality of surface waters, Devils Lake area P. G. Rosene ((1, Lincoln, Nebr.) Chemical quality of surface waters and sedimentation in the Grand River drainage basin P. R. Jordan (q, Lincoln, Nebr.) Chemical quality of surface waters and sedimentation in the Heart River drainage basin M. A. Maderak (q, Lincoln, Nebr.) Heimdal valley; Wells, Eddy, and Foster Counties (ground water) E. Bradley (g, Grand Forks, N. Dak.) Lakota area (ground water) E. Bradley (g, Grand Forks, N. Dak.) Special streamflow measurements of the Souris River at Minot E. Bradley (g, Grand Forks, N. Dak.) Strasburg-Linton area (ground water) P. Randich (g, Grand Forks, N. Dak.) Tioga area (ground water) 0. J. Huxel (g, Grand Forks, N. Dak.) REGIONAL INVESTIGATIONS IN PROGRESS Ohio: *Geology and coal resources of Belmont County H. L. Berryhill, Jr. (D) Seismic survey for buried valleys in Ohio R. M. Hazelwood (D) Floods of January and February 1959 W. P. Cross (s, Columbus, Ohio) Low flow and storage requirements W. P. Cross( s, Columbus, Ohio) Glacial mapping in Ohio G. W. White (g, Columbus, Ohio) Mapping of buried valleys S. E. Norris (g, Columbus, Ohio) Northeastern Ohio (ground water) J. L. Rau (g, Columbus, Ohio) Fairfield County (ground water) G. D. Dove (g, Columbus, Ohio) Geauga County (ground water) J. Baker (g, Columbus, Ohio) Portage County (ground water) J. D. Winslow (g, Columbus, Ohio) Canton area (ground water) J. D. Winslow (g, Columbus, Ohio) Dayton area (ground water) S. E. Norris (g, Columbus, Ohio) Hamilton-Middletown area S. E. Norris (g, Columbus, Ohio) Venice area A. M. Spieker (g, Columbus, Ohio) Oklahoma: Tri-State lead-zinc district, Oklahoma, Missouri, Kansas E. T. McKnight (W) Anadarko Basin, Oklahoma and Texas (oil and gas) W. L. Adkison (Lawrence, Kans.) McAlester Basin (oil and gas) .S. E. Frezon (D) *Ft. Smith district. Arkansas and Oklahoma (coal and gas) T. A. Hendricks (D) Trace elements in rocks of Pennsylvanian age, Oklahoma, Kansas, Missouri (uranium, phosphate) W. Danilchik (Quetta, Pakistan) Geology of the Anadarko Basin with reference to disposal of high-level radioactive wastes M. MacLachlan (D) Thickness of the fresh ground-water zone in Oklahoma D. L. Hart (g, Norman, Okla.) Water-quality conservation in the Arkansas and Red River basins P. E. Ward (g, Norman, Okla.) Saline surface-water resources of Oklahoma R. P. Orth (q, Oklahoma City, Okla.) Land-use evaluation F. W. Kennon (h, Oklahoma City, Okla.) Beaver County (ground water) I. XV. Marine (g, Norman, Okla.) Garber sandstone in Cleveland and Wellington Counties (ground water) A. R. Leonard (g, Norman, Okla.) Woodward County (ground water) B. L. Stacy (g, Norman, Okla.) Ground water in the Arbuckle limestone in the northeast- ern Arbuckle Mountains I. W. Marine (g, Norman, Okla.) A—131 Oklahoma—Continued Arkansas and Verdigris River valleys (ground water) H. H. Tanaka (g, Norman, Okla.) Upper Arkansas River basin (quality of surface water) R. P. Orth (q, Oklahoma City, Okla.) Beaver Creek basin (quality of surface water) R. P. Orth (q, Oklahoma City, Okla.) Clinton-Sherman Air Force Base (ground water) A. R. Leonard (g, Norman, Okla.) Little River basin (quality of surface water) G. Bednar (q, Oklahoma City, Okla.) Otter and Elk Creek basins (ground water) J. R. Hollowell (g, Norman, Okla.) Ground water in the Rush Springs sandstone H. H. Tanaka (g, Norman, Okla.) Washita River basin (quality of surface water) J. J. Murphy (q, Oklahoma City, Okla.) Oregon: Oregon state geologic map G. W. Walker (M) Cenozoic mollusks E. J. Moore (M) *‘Canyon City 2° quadrangle T. P. Thayer (W) *Monument quadrangle R. E. Wilcox (D) *Newport Embayment P.--.D. Snavely, Jr. (M) Origin of the borate-bearing marsh deposits of Cali- fornia, Oregon, and Nevada (boron) W. C. Smith (M) *John Day area (chromite) T. P. Thayer (W) *Quartzburg district (cobalt) J. S. Vhay (Spokane, Wash.) Lateritic nickel deposits of the Klamath Mountains, Oregon-California P. E. Hotz (M) ‘Anlauf and Drain quadrangles (oil and gas) L. Hoover (W) *Ochoco Reservation, Lookout Mountain, Eagle Rock, and Post quadrangles (quicksilver) A. C. Waters (Baltimore, Md.) Pacific Northwest geophysical studies W. E. Davis (W) Aeromagnetic and gravity studies in west-central Oregon R. W. Bromery (XV) Aerial radiological monitoring R. G. Schmidt (W) *Portland industrial area, Oregon and ‘Vashington (urban geology) D. E. Trimble (D) Sediment production of forested watersheds R. C. Williams (q, Portland, Oreg.) Appraisal of water quality and water-quality problems of selected streams R. J. Madison (q, Portland, Oreg.) Lower Columbia River Basin (quality of surface water) J. F. Santos (q, Portland, Oreg.) Columbia River basalt hydrology R. C. Newcomb (g, Portland, Oreg.) Artificial recharge of basalt aquifers at the Dalles B. L. Foxworthy (g, Portland, Oreg.) surveys, Hanford area A—132 Oregon—Continued Eola and Amity Hills (ground water) D. Price (g, Portland, Oreg.) Florence area (ground water) E. R. Hampton (g, Portland, Oreg.) Fort Rock basin (ground water) E. R. Hampton (g, Portland, Oreg.) French Prairie (ground water) D. Price (g, Portland, Oreg.) East Portland area (ground water) B. L. Foxworthy (g, Portland, Oreg.) West Portland area (ground water) S. G. Brown (g, Portland, Oreg.) Raft River basin water records M. J. Mundorff (g, Portland, Oreg.) Tumalo District, Deschutes County (ground water) B. L. Foxworthy (g, Portland, Oreg.) Northern Willamette valley east of Pudding River (ground water) E. R. Hampton (g, Portland, Oreg.) Pennsylvania : *Bituminous coal resources E. D. Patterson (W) Correlation of aeromagnetic studies and areal geology, Pennsylvania Triassic area R. W. Bromery (W) *Lower Delaware River Basin, New Jersey-Pennsylvania J. P. Owens (W) *Middle Delaware River Basin, New Jersey—Pennsylvania A. A. Drake, Jr. (W) *Glacial geology of the Elmira—Williamsport area, New York-Pennsylvania C. S. Denny (W) ‘Investigations of the Lower Cambrian of the Phila- delphia district J. H. Wallace (W) ‘Southern anthracite field G. H. Wood, Jr. (W) *Western middle anthracite field H. H. Arndt (W) *Flood control, Anthracite region T. M. Kehn (Mt. Carmel, Pa.) *Geology in the vicinity of anthracite mine drainage projects T. M. Kehn (Mt. Carmel, Pa.) Selected studies of uranium deposits H. Klemic (W) *Lehighton quadrangle (uranium) H. Klemic (W) Washington County (coal) H. Berryhill, Jr. (D) Flood-frequency analysis W. F. Busch (s, Harrisburg, Pa.) Low-flow frequency analysis W. F. Busch (s, Harrisburg, Pa.) Mining hydrology W. T. Stuart (g, W) Allegheny River basin water) D. McCartney (q, Philadelphia. Pa.) Chemical characteristics of Delaware River water D. McCartney (q, Philadelphia, Pa.) (chemical quality of surface GEOLOGICAL SURVEY RESEARCH 1961~SYNOPSIS OF RESULTS Pennsylvania—Continued Salinity conditions of Lower Delaware River basin D. McCartney (q, Philadelphia, Pa.) Lehigh River basin (quality of surface water) W. B. Keighton (q, Philadelphia, Pa.) Time of travel of Ohio River water R. E. Steacy (s, Harrisburg, Pa.) Potomac River basin P. M. Johnston (g, W) Raritan River basin (quality of surface water) J. R. George (q, Harrisburg, Pa.) Hydrology and sedimentation of Bixler Run, Creek, and Elk Run basins J. R. George (q, Harrisburg, Pa.) Brunswick formation (ground water) S. M. Longwill (g, Harrisburg, Pa.) Flood-inundation map, Harrisburg L. A. Heckmiller (s, Harrisburg, Pa.) Hydrology of limestones in the Lebanon Valley H. Meisler (g, Harrisburg, Pa.) Mercer and Neshannock quadrangles (ground water) C. W. Poth (g, Harrisburg, Pa.) New Oxford formation (ground water) P. R. Wood (g, Harrisburg, Pa.) Red Clay Valley (ground water) D. H. Boggess (g, Newark, Del.) Shenango and Stoneboro quad‘rangles L. D. Carswell (g, Harrisburg, Pa.) Rhode Island: *Ashaway quadrangle, Rhode Island~Connecticut; bedrock geologic mapping T. G. Feininger (B0ston, Mass.) *Carolina, Quonochontaug, Narragansett Pier, and Wickford quadrangleS, Rhode Island; and Ashaway and Watch Hill quadrangles, Connecticut-Rhode Is- land; surficial geologic mapping J. P. Schafer (Boston, Mass.) *Chepachet, Crompton, and Tiverton quadrangles; bedrock geologic mapping A. W. Quinn (Providence, RI.) *Coventry Center, Kingston, and Newport quadrangles. Rhode Island; and Watch Hill quadrangle, Con- necticut-Rhode Island; bedrock geologic mapping G. E. Moore, Jr. (Columbus, Ohio) *Hope Valley quadrangle; surficial geologic mapping T. G. Feininger (Boston, Mass.) *Kingston quadrangle; surficial geologic mapping C. A. Kaye (Boston, Mass.) *North Scituate quadrangle; surficial geologic mapping C. S. Robinson (D) *Thompson quadrangle, Connecticut-Rhode Island P. M. Hanshaw (Boston, Mass.) ‘Wickford quadrangle; bedrock geologic mapping R. B. Williams (Providence, RI.) Oneco quadrangle (ground water) K. E. Johnson (g, Providence, RI.) Upper Pawcatuck basin (ground water) W. B. Allen (g, Providence, RI.) Voluntown quadrangle (ground water) K. E. Johnson (g, Providence, RI.) Watch Hill quadrangle (ground water) K. E. Johnson (g, Providence, RI.) Corey REGION-AL INVESTIGATIONS IN PROGRESS South Carolina: Crystalline rocks of South Carolina W. C. Overstreet (W) Aerial radiological monitoring surveys, Plant, Georgia and South Carolina R. G. Schmidt (W) Flood gaging W. W. Evett (s, Columbia, SC.) Drainage-area determinations W. M. Bloxham (s, Columbia, SC.) Flood-frequency analysis F. H. Wagener (s, Columbia, SC.) Artesian water in Tertiary limestones in Florida, southern Georgia, and adjacent parts of Alabama and South Carolina V. T. Stringfield (w, W) Stratigraphy of the Trent marl and related units P. M. Brown (g, Raleigh, NC) Northeastern coastal plain (ground water) G. E. Siple (g, Columbia, S.C.) Coastal plain (ground water) G. E. Siple (g, Columbia, SC.) Flood-plain aquifers G. E. Siple (g, Columbia, SC.) Salt-water intrusion in Lower Edisto River basin G. A. Billingsley (q, Raleigh, NC.) Santee River basin flood study A. E. Johnson (s, Columbia, SC.) Savannah River AEC plant (ground water) N. C. Koch (g, Columbia, SC.) South Dakota: Chemical and physical properties of the Pierre shale, Mon- tana, North Dakota, South Dakota, Wyoming, and Nebraska H. A. Tourtelot (D) Williston Basin oil and gas studies, Wyoming, Montana, North Dakota, and South Dakota C. A. Sandberg (D) Geology of the Williston Basin with reference to the disposal of high-level radioactive wastes .C. A. Sandberg (D) ‘Southern Black Hills (pegmatite minerals) J. J. Norton (W) *Pegmatites of the Custer district J. A. Redden (Blacksburg, Va.) ‘Structure and metamorphism, Hill City quadrangle (peg- matite minerals) J. C. Ratté (D) ‘Southern Black Hills (uranium) G. B. Gott (D) *Harding County, South Dakota, and adjacent areas ( uranif- erous lignite) G. N. I’ipiringos (D) Regional gravity studies in uranium geology, Black Hills area R. M: Hazlewood (D) Landslide studies in the Fort Randall Reservoir area H. D. Varnes (D) Studies of artesian wells and selected shallow aquifers C. F. Dyer (g, Huron, S. Dak.) Peak discharges from small areas R. E. West (s, Pierre, S. Dak.) Savannah River 608400 0—61—10 A—133 South Dakota—Continued Hydrology of prairie potholes J. B. Shjeflo (h, D) Hydrology of glacial drift in selected drainage basins in eastern South Dakota M. J. Ellis (g, Huron, S. Dak.) Dakota sandstone (ground water) C. F. Dyer (g, Huron, S. Dak.) Minor constituents in the Belle Fourche River L. R. Petri (q, Lincoln, Nebr.) Cheyenne and Standing Rock Indian Reservations (ground water) J. E. Powell (g, Huron, S. Dak.) Flandreau area (ground water) J. E. Powell (g, Huron, S. Dak.) Chemical quality of surface waters and sedimentation in the Grand River drainage basin P. R. Jordan ( q, Lincoln, Nebr.) Sanborn County (ground water) L. W. Howells (g, Huron, S. Dak.) Shadehill Reservoir area (ground water) J. E. Powell (g, Huron, S. Dak.) Tennessee : *Geology of the southern Appalachian folded belt, Kentucky, Tennessee, and Virginia L. D. Harris (W) *Great Smoky Mountains, Tennessee and North Carolina J. B. Hadley (D) Ivydell, Pioneer, J ellico West, and Ketchen quadrangles .(coal) K. J. Englund (W) Massive sulfide deposits of the Ducktown district, Ten- nessee and adjacent areas (copper, iron, sulfur) R. M. Hernon (D) Clinton iron ores of the southern Appalachians R. P. Sheldon (D) *East Tennessee zinc studies A. L. Brokaw (D) Origin and depositional control of some Tennessee and Virginia zinc deposits H. Wedow, Jr. (Knoxville, Tenn.) Central and western North Carolina regional aeromagnetic survey R. W. Johnson, Jr. (Knoxville, Tenn.) Aeromagnetic studies, Middlesboro-Morristown area, Ten- nessee-Kentucky—Virginia R. W. Johnson, Jr. (Knoxville, Tenn.) Aeromagnetic study of peridotite, Maynardville R. W. Johnson, Jr. (Knoxville, Tenn.) Aerial radiological monitoring surveys, Oak Ridge National Laboratory R. G. Bates (W) *Knoxville and vicinity (urban geology) J. M. Cattermole (D) Low-flow studies J. S. Cragwall, Jr. (s, Chattanooga, Tenn.) Flood-frequency analysis W. J. Randolph (s, Chattanooga, Tenn.) Bridge-site studies (surface water) I. J. Hickenlooper (s, Chattanooga, Tenn.) Large springs of eastern Tennessee P. C. Sun (g, Nashville, Tenn.) A—134: GEOLOGICAL SURVEY RESEARCH 196l—SYNOPSIS OF RESULTS Tennessee—Continued Texas—Continued Western Tennessee (ground water) Galveston area (ground water) G. K. Moore (g, Nashville, Tenn.) R. B. Anders (g, Austin, Tex.) Flood profiles, Chattanooga Creek Houston district (ground water) A. M. F. Johnson (s, Chattanooga, Tenn.) R. B. Anders (g, Austin, Tex.) Dover area (ground water) San Antonio area (ground water) M. V. Marcher (g, Nashville, Tenn.) S. Garza (g, Austin, Tex.) Highland Rim Plateau (ground water) Brazos River saline investigations M. V. Marcher (g, Nashville, Tenn.) J- 0- J 061115 (S, Austin, Tex.) Madison County (ground water) Sources of salinity in the Upper Brazos River basin D. J. Nyman (g, Nashville, Tenn.) R. C. Baker (g. Austin, Tex.) Memphis area (ground water) Sources of salinity in the Upper Brazos River basin P. C. Sun (g, Nashville, Tenn.) L- S- Hughes ((1. Austin, Tex.) (High Plains north of the Canadian River (ground water) W. H. Alexander (g, Austin, Tex.) Upper and lower Rio Grande basins, Brazos, Red, and Gulf Coast basins (ground water) L. A. Wood (g, Austin, Tex.) Middle Rio Grande basin, Colorado, Trinity, and Sabine River basins (ground water) R. C. Peckham (g, Austin ,Tex.) Low—flow investigations, Sabine River P. H. Holland (s, Austin, Tex.) Sedimentation conditions in Upper Trinity River basin 0. T. Welborn (q, Austin, Tex.) Texas: *Del Rio area V. L. Freeman (D) *Sierra Blanca area J. F. Smith, Jr. (D) *Sierra Diablo region P. B. King (M) Sierra Madera E. M. Shoemaker (M) Anadarko Basin, Oklahoma and Texas (oil and gas) W. L. Adkison (Lawrence, Kans.) *Franklin Mountains, New Mexico and Texas (petroleum) R. L. Harbour (D) Utah: *Wayland quadrangle (oil and gas investigations) General geology: D. A. Myers (D) Upper Cretaceous stratigraphy, northwestern Colorado and Mineralogy of uranium-bearing rocks in Karnes and Duval northeastern Utah ' Counties A. D. Zapp (D) A. D. Weeks (W) Tuffs of the Green River formation *Texas coastal plain geophysical and geological studies R- L- Griggs (D) D. H. Eargle (Austin, Tex.) *Northern Bonneville Basin Aerial radiological monitoring surveys, Fort Worth J- S- Williams (Provo, Utah) J. A. Pitkin (W) *Cedar City area Use of tritium in hydrologic studies P- Averitt (D) C. W. Carlston (g, W) *Confusion Range Drainage-area determinations, Sabine, Neches, San Jacinto, 'R- K- Hose (M) and Trinity River basins *Little Cottonwood area P. H. Holland (S, Austin, Tex.) G. M. Richmond (D) Hydrologic investigations, small watersheds, Trinity, *Strawberry Valley 311d Wasatch Mountains Brazos, Colorado, and San Antonio River basins A- A- Baker (\V) \V. H. Goines (s, Austin, Tex.) *South half, Utah Valley Thermal surveys, Lake Colorado City H. J- Bissell (PTOVO. Utah) G. H. Hughes (s, Austin, Tex.) Mineral resources: Field testing of evaporation suppression on small reservoirs Geochemical halos 0f mineral deposits, Utah and Nevada G. E. Koberg (h, D) R. L. Erickson (D) Hydrologic effect of small reservoirs, Honey Creek *Marysvale diStI‘iCt (alunite) F. \v. Kennon (h, Oklahoma City, Okla.) R. L. Parker (D) Evaporation suppression studies (Throckmorton) *Cedar Mountain quadrangle, Iron County (coal) G. E. Koberg (h, D) P. Averitt (D) Trap-efficiency of reservoir on Escondido Creek *Southern K0101) Terrace 0031 field C. T. \Velborn (q, Austin, Tex.) W- B. Cashion (D) Carson and adjoining counties (ground water) *Regional geologic setting of the Bingham Canyon district A. T. Long (g, Austin, Tex.) (cooper) Haskell and Knox Counties (ground water) R- J- Roberts (M) W. Ogilbee (g, Austin, Tex.) Thomas and Dugway Ranges (fluorspar, beryllium) Northern Jim Wells County and adjacent areas (ground M- H- Staatz (D) water) *Fuels potential of the Navajo Reservation, Arizona and C. C. Mason (g, Austin, Tex.) Utah Hydrologic investigations, urban watershed, Austin 3- 13- O’Sullivan (D) A- E- Hulme (S, Austin, Tex.) *Alta quadrangle (lead, silver, phosphate rock) El Paso area (ground water) M. D. Crittenden, Jr. (M) M. E. Davis (g, Austin, Tex.) REGIONAL INVESTIGATIONS IN PROGRESS Utah—Continued Mineral resources—Continued *East Tintic lead-zinc district, including extensive geochem- ical studies H. T. Morris (M) *San Francisco Mountains (base metals, tungsten) D. M. Lemmon (M) *Uinta Basin oil shale W. B. Cashion (D) Stratigraphy and resources of the Phosphoria and Park City formations in Utah and Nevada (phosphate, minor elements) K. M. Tagg (M) *Wheeler Peak and Garrison quadrangles, Snake Range, Nevada and Utah (tungsten, beryllium) D. H. Whitebread (M) "Compilation of Colorado Plateau geologic maps (uranium, vanadium) D. G. Wyant (D) Uranium-vanadium deposits in sandstone, with emphasis on the Colorado Plateau R. P. Fischer (D) Relative concentrations of chemical elements in different rocks and ore deposits of the Colorado Plateau (uranium, vanadium, copper) A. T. Miesch (D) Colorado Plateau botanical prospecting studies F. J. Kleinhainpl (M) Clay studies, Colorado Plateau L. G. Schultz (D) Lithologic studies, Colorado Plateau R. A. Cadigan (D) Stratigraphic studies, ‘ nadium) L. C. Craig (D) Triassic stratigraphy and lithology of the Colorado Plateau (uranium, copper) J. H. Stewart (D) San Rafael group stratigraphy, Colorado Plateau (ura‘ nium) J. C. Wright (D) *A'bajo Mountains (uranium, vanadium) I. J. Witkind (D) ‘Circle Cliffs area (uranium) E. S. Davidson (Tucson, Ariz.) *Deer Flat area, White Canyon district (uranium, copper) T. L. Finnell (D) *Elk Ridge area (uranium) R. Q. Lewis (D) *La Sal area, Utah-Colorado (uranium, vanadium) W. D. Carter (Santiago, Chile) *Lisbon Valley area, Utah-Colorado (uranium, vanadium, copper) G. W. Weir (M) *Interriver area, east-central Utah (uranium) E. N. Hinrichs (D) *Orange Cliifs area (uranium) F. A. McKeown (D) *Sage Plain area (uranium and vanadium) L. C. Huff (D) Uranium ore controls of the San Rafael Swell C. C. Hawley (D) Colorado Plateau (uranium, var A—135 Utah—Continued Mineral resources—Continued *White Canyon area (uranium, copper) R. E. Thaden (D) Western oxidized zinc deposits A. V. Heyl (W) Engineering geology and geophysical studies: *Geologic factors related to coal mine bumps F. W. Osterwald (D) *Upper Green River Valley (construction-site planning) W. R. Hansen (D) *Surficial geology of the Oak City area (construction-site planning) D. J. Varnes (D) Colorado Plateau regional geophysical studies H. R. Joesting (XV) Great Basin geophysical studies D. R. Mabey (M) Water resources: Flood gaging V. K. Berwick (s, Salt Lake City, Utah) Pumping districts of southern Utah (ground water) G. W. Sandberg (g, Salt Lake City, Utah) Dissolved mineral contributions to Great Salt Lake A. M. Diaz ((1, Salt Lake City, Utah) Study of the mechanics of hillslope erosion S. A. Schumm (h, D) Evaluation of sediment barrier on Sheep Creek, Paria River Basin, near Tropic G. C. Lusby (h, D) Dinosaur National Monument (ground water) R. E. Smith (g, Salt Lake City, Utah) Lodore Canyon, Deerlodge Park, and Dinosaur National Monument (ground water) R. E. Smith (g, Salt Lake City, Utah) East Shore area (ground water) R. E. Smith (g, Salt Lake City, Utah) Jordan Valley (ground water) I. W. Marine (g, Salt Lake City, Utah) Pavant Valley (ground water) R. W. Mower (g, Salt Lake City, Utah) Central Sevier Valley (ground water) R. A. Young (g, Salt Lake City, Utah) Upper Sevier Valley (ground water) R. A. Young (g, Salt Lake City, Utah) Tooele Valley (ground water) H. D. Goode (g, Salt Lake City, Utah) Uinta Basin (ground water) H. D. Goode (g, Salt Lake City, Utah) Northern Utah Valley (ground water) S. Subitzky (g, Salt Lake City, Utah) Wasatch front (ground water) R. E. Smith (g, Salt Lake City, Utah) Weber Basin (ground water) J. H. Feth (g, Salt Lake City, Utah) Vermont: *Talc and asbestos deposits of north-central Vermont W. M. Cady (D) Correlation of aeromagnetic studies and areal geology, i'ew Hampshire and Vermont R. W. Bromery (W) A—136 Virginia: *Geology of the southern Appalachian folded belt, Kentucky, Tennessee, and Virginia L. D. Harris (W) *Potomac Basin studies, Maryland, Virginia, and West Vir- ginia J. T. Hack (W) *Herndon quadrangle (construction-site planning) R. E. Eggleton (D) *Petrology of the Manassas quadrangle C. Milton (W) Origin and depositional control of some Tennessee and Virginia zinc deposits H. Wedow, J r. (Knoxville, Tenn.) Massive sulfide deposits of the Ducktown district, Tennes- see and adjacent areas (copper, iron, sulfur) R. M. Hernon (D) Aerial radiological monitoring surveys, Belvoir area, Vir- ginia and Maryland S. K. Neuschel (W) Aeromagnetic studies, Middlesboro-Morristown area, Ten- nessee-Kentucky-Virginia R. W. Johnson, Jr. (Knoxville, Tenn.) Hydrologic and! hydraulic studies C. W. Lingham (s, Charlottesville, Va.) Flood investigations C. W. Lingham (s, Charlottesville, Va.) Flood-plain zoning D. G. Anderson (s, Charlottesville, Va.) Flood hydrology, Fairfax County and Alexandria City D. G. Anderson (s, Charlottesville, Va.) Effect of urbanization of peak discharge R. W. Carter (s, W) Potomac River basin P. M. Johnston (g, W) Washington: *Bald Knob quadrangle M. H. Staatz (D) *Glacier Peak quadrangle D. F. Crowder (M) *Grays Harbor basin H. D. Gower (M) *Northern Olympic Peninsula R. D. Brown, Jr. (M) Osceola mudflow studies D. R. Crandell (D) *Republic quadrangle J. A. Calkins (D) “Geologic mapping of the Spokane-Wallace region, Washing- ton-Idaho A. B. Griggs (M) *Greenacres quadrangle, Washington-Idaho (high-alumina clays) P. L. Weis (Spokane, Wash.) Coal resources H. D. Gower (M) *Maple Valley, Hobart and Cumberland quadrangles, King County (coal) J. D. Vine (M) *Holden and Lucerne quadrangles, Northern Cascade Moun- tains (copper) F. W. Cater (D) GEOLOGICAL SURVEY RESEARCH 196l—SYNOPSIS OF RESULTS Washington—Continued *Metaline lead-zinc district M. G. Dings (D) *Stevens County lead-zinc district R. G. Yates (M) ‘Chewelah area (magnesite) I. Campbell (San Francisco, Calif.) *Hunters quadrangle (magnesite, tungsten, barite) A. B. Campbell (D) *Mt. Spokane quadrangle (uranium) A. E. Weissenborn (Spokane, Wash.) *Turtle Lake quadrangle (uranium) G. E. Becraft (D) Pacific Northwest geophysical studies W. E. Davis (W) Gravity survey of western Washington D. J. Stuart (W) Aerial radiological monitoring surveys, Hanford R. G. Schmidt (W) *Portland industrial area, Oregon and Washington (urban geology) D. E. Trimble (D) *Puget Sound basin (urban geology and construction-site planning) D. R. Mullineaux (D) Engineering geologic studies of Seattle D. R. Mullineaux (D) Drainage area compilation D. Richardson (s, Tacoma, Wash.) Effect of changes in forest cover on streamflow F. M. Veatch (s, Tacoma, Wash.) Glacialogical research M. F. Meier (h, Tacoma, Wash.) Geomorphology of glacier streams R. K. Fahnestock (h, Fort Collins, Colo.) Relationship of ground-water storage and streamflow, Columbia River basin A. A. Garrett (g, Tacoma, Wash.) Columbia River basalt hydrology R. C. Newcomb (g, Portland, Oreg.) Columbia Basin Irrigation Project (ground water) J. W. Bingham (g, Tacoma, Wash.) Lower Columbia River basin (quality of surface water). J. F. Santos (q, Portland, Oreg.) Grant, Adams, and Franklin Counties (ground water) M. J. Grolier (g, Tacoma, Wash.) Southwest King County (ground water) K. L. Walters (g, Tacoma, Wash.) Central Pierce County (ground water) K. L. Walters (g, Tacoma, Wash.) Thurston County (ground water) E. F. Wallace (g, Tacoma, Wash.) Whitman County (ground water) K. L. Walters (g, Tacoma, Wash.) Whitman National Monument (ground water) J. W. Bingham (g, Tacoma, Wash.) Hydrology of Lower Flett Creek basin F. M. Veatch (s, Tacoma, Wash.) Kitsap Peninsula (surface water) E. G. Bailey (s, Tacoma, Wash.) N ooksack River basin (surface water) E. G. Bailey (5, Tacoma, Wash.) base metals, REGIONAL INVESTIGATIONS IN PROGRESS A—137 West Virginia : *Potomac Basin studies, Maryland, Virginia, and West Virginia J. T. Hack (W) Aerial radiological monitoring surveys, Belvoir area, Virginia and Maryland S. K. Neuschel (W) General hydrology W. L. Doll (s, Charleston, W. Va.) Potomac River basin (ground water) P. M. Johnson (g, W) Lower Kanawha River valley (ground water) B. M. ,Wilmoth (g. Morgantown, W. Va.) Ohio County (ground water) G. Meyer (g, Morgantown, W. Va.) Teays Valley (ground water) E. C. Rhodehamel (g, Morgantown, W. Va.) Wisconsin : ‘Florence County (iron) C. E. Dutton (Madison, Wis.) *Wisconsin zinc-lead mining district J. W. Whitlow (D) ‘Stratigraphy of the lead-zinc district near Dubuque J. W. Whitlow (W) Geophysical studies in the Lake Superior region G. D. Bath (M) Correlation of aeromagnetic studies and areal geology, Florence County R. W. Johnson, Jr. (Knoxville, Tenn.) Correlation of aeromagnetic studies and areal geology near Wausau J. W. Allingham (W) Regional flood frequency D. W. Ericson (8, Madison, Wis.) Exploration of valley fills by seismic refraction G. H. Dury (W, W) Northwestern Wisconsin (ground water) R. W. Ryling (g, Madison, Wis.) Dane County (ground water) D. R. Cline (g, Madison, Wis.) Portage County (ground water) C. L. R. Holt (g, Madison, Wis.) Rock County (ground water) E. F. LeRoux (g, Madison, Wis.) Waupaca County (ground water) C. F. Berkstresser (g, Madison, Wis.) Waushara County (ground water) W. K. Summers (g, Madison, Wis.) Evolution of Black Earth Creek and Mounds Creek G. H. Dury (w, W) Green Bay area (ground water) D. B. Knowles (g, Madison, Wis.) Milwaukee area (ground water) R. W. Ryling (g, Madison, Wis.) Little Plover River basin (ground water) D. B. Knowles (g, Madison, Wis.) Wyoming : General geology and engineering geology : Pennsylvanian and Permian stratigraphy, Rocky Mountain Front Range, Colorado and Wyoming E. K. Maughan (D) Investigation of Jurassic stratigraphy, south-central Wyoming and northwestern Colorado G. N. Pipiringos (D) ‘Vyoming—Continued General geology and engineering geology—Continued Chemical and physical properties of the Pierre shale, Montana, North Dakota, South Dakota, Wyoming, and Nebraska. H. A. Tourtelot (D) Stratigraphy and paleontology of the Pierre shale, Front Range area, Colorado and Wyoming W. A. Cobban and G. R. Scott (D) Geology and paleolimnology of the Green River formation ” \V. H. Bradley (W) Mineralogy and geochemistry of the Green River formation C. Milton (W) Tufts of the Green River formation R. L. Griggs (D) Geology of the Williston Basin with reference to the disposal of high-level radioactive wastes C. A. Sandberg (D) *Big Piney area S. S. Oriel (D) *Clark Fork area W. G. Pierce (M) *Cokeville quadrangle W. W. Rubey (W) *Fort Hill quadrangle S. S. Oriel (D) Fossil Basin, southwest Wyoming J. I. Tracey, Jr. (W) *Geology of Grand Teton National Park J. D. Love (Laramie, Wyo.) *Upper Green River valley (construction-site planning) W. R. Hansen (D) Geology of the Powder River basin with reference to the disposal of high-level radioactive wastes II. Beikman (D) *Storm Hill quadrangle G. A. Izett (D) *Quaternary geology of the Wind River Mountains G. M. Richmond (D) Chemical composition of thermal waters in Yellowstone Park G. W. Morey (W) Gravity studies; Yellowstone area H. L. Baldwin (D) Mineral resources: *Green River formation, Sweetwater County (oil shale, salines) W. C. Culbertson (D) Williston Basin oil and gas studies, Wyoming, Montana, North Dakota, and South Dakota C. A. Sandberg (D) *Beaver Divide area (oil and gas) F. B. Van Houten (Princeton, N.J.) ‘Crowheart Butte area (oil and gas) J. F. Murphy (W) *Shotgun Butte (oil and gas) \V. R. Keefer (Laramie, \Vyo.) ‘Whalen-Wheatland area (oil and gas) L. \V. McGrew (Laramie, Wyo.) Regional geology of the Wind River Basin (oil and gaS) W. R. Keefer (Laramie, Wyo.) A—138 Wyoming—Continued Mineral resources—Continued *Atlantic City district (iron, gold) R. W. Bayley (M) Titaniferous black sands in Upper Cretaceous rocks R. S. Houston (Laramie, Wyo.) *Regional stratigraphic study of the Inyan Kara group, Black Hills (uranium) W. J. Mapel (D) Regional gravity studies in uranium geology, Black Hillsarea R. M. Hazlewood (D) Uranium and phosphate in the Green River formation W. R. Keefer (Laramie, Wyo.) ‘Baggs area, Wyoming and Colorado (uranium) G. E. Prichard (D) ‘Crooks Gap area, Fremont County (uranium) J. G. Stephens (D) *Gas Hills district (uranium) H. D. Zeller (D) *Hiland-Clarkson Hills area (uranium) E. I. Rich (M) Shirley basin area, (uranium) E. N. Harshman (D) *Southern Powder River basin (uranium) W. N. Sharp (D) *Pumpkin Buttes area, Powder River Basin (uranium) W. N. Sharp (D) *Western Red Desert area (uranium in coal) G. N. Pipiringos (D) Water resources: Mining hydrology W. T. Stuart (g, W) Effects of sediment on the propagation of trout in small streams A. R. Gustafson (q, Worland, Wyo.) The effects of exposure on slope morphology R. F. Hadley (h, D) Northern and western Crook County (ground water) H. A. Whitcomb (g, Cheyenne, Wyo.) Johnson County (chemical quality of ground water) T. R. Cummings (q, Worland, Wyo.) Northern Johnson County (ground water) R. A. McCullough (g, Cheyenne, Wyo.) Niobrara County (ground water) H. A. Whitcomb (g, Cheyenne, Wyo.) Sheridan County (ground water) M. E. Lowry (g, Cheyenne, Wyo.) Sheridan County (chemical quality of ground water) T. R. Cummings (q, Worland, Wyo.) Cheyenne area (ground water) E. D. Gordon (g, Cheyenne, Wyo.) Devils Tower National Monument (ground water) E. D. Gordon (g, Cheyenne, Wyo.) Grand Teton National Park (ground water) E. D. Gordon (g, Cheyenne, Wyo.) Lyman-Mountain View area (ground water) 0. J. Robinove (g, Cheyenne, Wyo.) Wheatland Flats area (ground water) E. P. Weeks (g, Cheyenne, Wyo.) Sedimentation and chemical quality of surface waters in the Wind River Basin R. C. Williams (q, Worland, Wyo.) GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Wyoming—Continued Water resources—Continued Bridge Bay, Yellowstone National Park (ground water) E. D. Gordon (g, Cheyenne, Wyo.) Puerto Rico and Caribbean area: *Geology and mineral resources of Puerto Rico W. H. Monroe (San Juan, Puerto Rico) Carbonate sediments, Bahama Banks P. E. Cloud (W) Cenozoic faunas, Caribbean area W. P. Woodring (W) Recent Foraminifera, Central America P. J. Smith (M) Flood investigations, Puerto Rico H. H. Barnes (s, Atlanta, Ga.) Public water supplies in Puerto Rico T. Arnow (g, San Juan, Puerto Rico) (Puerto Rico (surface water) D. B. Bogart (s, San Juan, Puerto Rico) Lower Tallaboa Valley, Puerto Rico (ground water) I. G. Grossman (g, San J uan, Puerto Rico) Guantanamo Bay, Cuba (ground water) H. Sutcliffe (g, Tallahassee, Fla.) Western Pacific Islands: Cenozoic Foraminifera, Pacific Ocean and Islands M. R. Todd (W) Cenozoic gastropods and pelecypods, Pacific Islands F. S. MacNeil (M) Cenozoic mollusks, Pacific Islands H. S. Ladd (W) Pacific Islands vegetation F. R. Fosberg (W) *Bikini and nearby atolls H. S. Ladd (W) “Guam J. I. Tracey, Jr. (W) *Ishigaki, Ryukyu Islands H. L. Foster (W) Vertebrate faunas, Ishigaki Ryukyu Islands F. C. Whitmore, Jr. (W) Thermal and seismic studies in the Marshall Islands J. H. Swartz (W) *Okinawa G. Corwin (W) *Pagan Island G. Corwin (W) ‘Palau Islands G. Corwin (W) ‘Tinian D. B. Doan (W) *Truk J. T. Stark (Recife, Brazil) ’Yap and Caroline Islands C. G. Johnson (Honolulu, Hawaii) Guam (ground water) D. A. Davis (g, Honolulu, Hawaii) Southern Okinawa (ground water) D. A. Davis (g, Honolulu, Hawaii) American Samoa (ground water) K. J. Takasaki (g, Honolulu, Hawaii) Tutuila, American Samoa (surface water) H. H. Hudson (s, Honolulu, Hawaii) REGIONAL INVESTIGATIONS IN PROGRESS Antarctica: Reconnaissance geology along the Eights and Walgreen Coasts IA. A. Drake, Jr. (W) Reconnaissance geology, eastern Horlick Mountain E. L. Boudette (W) Reconnaissance geology, central Marie Byrd Land E. L. Boudette (W) Reconnaissance geology, Thurston Peninsula H. A. Hubbard (W) Geologic and hydrologic investigations in other countries: Afghanistan—surface-Water resources of Helmand River basin R. H. Brigham (w, Lashkar Gah, Afghanistan) Argentina—governmental ground-water investigatory serv— ices (advisory) S. L. Schoff (w, Buenos Aires, Argentina) Bolivia—mineral resources and geologic mapping (advising and training) C. M. Tschanz (LaPaz, Bolivia) *Brazil—iron and manganese resources, Minas Gerais J. V. N. Dorr II (Belo Horizonte, Brazil) *Brazil—base-metal resources A. J. Bodenlos (Rio de J aneiro, Brazil) Brazil—geological education A. J. Bodenlos (Rio de J aneiro, Brazil) Brazil—uranium resources (training) 0. T. Pierson (Rio de J aneiro, Brazil) Brazil—governmental ground-water investigatory services (advisory) R. Schneider (w, Rio de J aneiro, Brazil) *Chilchmineral resources and national geologic mapping R. J. Dingman (Santiago, Chile) Chil%ground-water investigations and hydrogeologic map- ping R. J. Dingman (w, Santiago, Chile) “Greenland, eastern—surficial geology planning) W. E. Davies (W) India—mineral resources (advisory) L. V. Blade (Calcutta, India) Indonesia—«economic and engineering geology (advisory and training) R. F. Johnson (Bandung, Indonesia) Iran—nationwide river basin surveys A. F. Pendleton (W, Teheran, Iran) ”Libya—industrial minerals and national geologic map G. H. Goudarzi (Tripoli, Libya) Libya—ground-Water investigation and development J. R. Jones (w, Benghazi, Libya) (construction-site A—139 Geologic and hydrologic investigations in other countries—Con. Mexico—training in regional geologic mapping R. L. Miller (Mexico, D.F., Mexico) N etherlands—origin of salt ground water J. E. Upson (g, Mineola, N.Y.) Pakistan—mineral resources development (advisory and training) J. A. Reinemund (Quetta, Pakistan) Pakistan—ground-water investigations and hydrogeologic mapping D. W. Greenman (w, Lahore, Pakistan) ”Philippines—iron, chromite and nonmetallic mineral re- sources J. F. Harrington (Manila, P.I.) Philippines—water-resources investigations (advisory) C. R. Murray (w, Manila, P.I.) "Saudi Arabia—national geologic map G. F. Brown (Jidda, Saudi Arabia) Southern Rhodesia—areal ground-water investigations (ad- visory) P. E. Dennis (w, Salisbury, Southern Rhodesia) *Taiwan—economic geology (training) S. Rosenblum (Taipei, Taiwan) Thailand—economic geology and mineral industry expan- sion (advisory) L. S. Gardner (Bangkok, Thailand) Tunisia—groundwater investigations and hydrogeologic mapping . H. E. Thomas (w, Tunis, Tunisia) Turkey—Geological education, University of Istanbul (training) Q. D. Singewald (Istanbul, Turkey) Turkey—nationwide surface-water investigations C. C. Yonker (w, Ankara, Turkey) United Arab Republic (Egypt)—ground-water investigation of the western desert H. A. Waite (w, Cairo, Egypt) Extraterrestrial studies: Photogeology of the moon; lunar photometry W. A. Fischer (W) Photogeology of the moon; stratigraphy and structure R. J. Hackman (W) Terrane study of the moon A. 0. Mason (W) Mineralogy and petrology of meteorites and tektites E. C. T. Chao (W) Chemistry of tektites F. Cuttita (W) A—l40 GEOLOGICAL SURVEY RESEARCH 196l—SYNOPSIS OF RESULTS TOPICAL INVESTIGATIONS Heavy metals District studies: Ferrous and ferro-alloy metals: *Selected iron deposits of the Northeastern States A. F. Buddington (Princeton, NJ.) Correlation of aeromagnetic studies and areal geology, Adirondacks area, New York (iron) J. R. Balsley (W) Correlation of aeromagnetic studies and areal geology, New York-New Jersey Highlands (iron) A. Jespersen (W) Clinton iron ores of the southern Appalachians R. P. Sheldon (D) *Iron River-Crystal Falls district, Michigan (iron) H. L. James (M) ‘Eastern Iron County, Michigan (iron) K. L. Wier (Iron Mountain, Mich.) *Southern Dickinson County, Michigan (iron) R. W. Bayley (M) *East Marquette district, Michigan (iron) J. E. Gair (D) ‘Florence County, Wisconsin (iron) C. E. Dutton (Madison, Wis.) ‘Cuyuna North Range, Minnesota (iron) R. G. Schmidt (W) Iron ore deposits of Nevada R. G. Reeves (M) *Atlantic City district, Wyoming (iron, gold) R. W. Bayler (M) *Unionville and Buffalo Mountain quadrangles, Humboldt Range, Nevada (iron, tungsten, silver, quicksilver) R. E. Wallace (M) Ore deposits of southwestern Montana H. L. James (M) “Klukwan iron district, Alaska E. C. Robertson (W) *Southeastern Aroostook County, Maine (manganese) L. Pavlides (W) Manganese deposits of the Philipsburg area, Montana (manganese and base metals) W. C. Prinz (Spokane, Wash.) *John Day area, Oregon (chromite) T. P. Thayer (W) Lateritic nickel deposits of the Klamath‘ Mountains, (Oregon-California P. E. Hotz (M) ‘Hamme tungsten deposit, North Carolina J. M. Parker, 3d (Raleigh, N.C.) *Wheeler Peak and Garrison quadrangles, Snake Range, Nevada and Utah (tungsten and beryllium) D. H. Whitebread (M) *Osgood Mountains quadrangle, Nevada (tungsten, quick- silver) P. E. Hotz (M) ’Bishop tungsten district, California P. C. Bateman (M) ‘Eastern Sierra tungsten area, California ; Devil’s Post- pile, Mt. Morrison, and Casa Diablo quadrangles (tungsten, base metals) C. D. Rinehart (M) Heavy metals—Continued District studies—Continued Ferrous and ferro—alloy metals—Continued ‘Geologic study of the Sierra Nevada batholith, California (tungsten, gold, base metals) P. C. Bateman (M) *Blackbird Mountain area, Idaho (cobalt) J. S. Vhay (Spokane, Wash.) ‘Quartzburg district, Oregon. (cobalt) J. S. Vhay (Spokane, Wash.) *Thunder Mountain niobium area, Montana-Idaho R. L. Parker (D) Magnet Cove niobium investigations, Arkansas L. V. Blade (Paducah, Ky.) Base and precious metals: *Swain County copper district, North Carolina G. H. Espenshade (W) Massive sulfide deposits of the Ducktown district, Ten- nessee and adjacent areas (copper, iron, sulfur) R. M. Hernon (D) *Michigan copper district W. S. White (W) Copper deposits in sandstone C. B. Read (Albuquerque, N. Mex.) *Silver City region, New Mexico (copper, zinc) W. R. Jones (D) *Bradshaw Mountains, Arizona (copper) C. A. Anderson (W) ‘Christmas quadrangle, Arizona (copper, iron) C. R. Willden (M) *Globe-Miami area, Arizona (copper) N. P. Peterson (Globe, Ariz.) *Klondyke quadrangle, Arizona (copper) F. S. Simons (D) Contact-metamorphic deposits of the Little Dragoons area, Arizona (copper) J. R. Cooper (D) *Mammoth and Benson quadrangles, Arizona (copper) S. C. Creasey (M) *Prescott-Paulden area, Arizona (copper) M. H. Krieger (M) *Twin Buttes area, Arizona (copper) *J. R. Cooper (D) *Regional geologic setting of the Bingham Canyon district, Utah (copper) R. J. Roberts (M) *Regional geologic setting of the Ely district, Nevada (copper, lead, zinc) A. L. Brokaw (D) *Lyon, Douglas, and Ormsby Counties, Nevada (copper) J. G. Moore (M) Structural geology of the Sierra foothills mineral belt, California (copper, zinc, gold, chromite) L. D. Clark (M) *Holden and Lucerne quadrangles, Northern Cascade Mountains, Washington (copper) F. W. Cater (D) “Southern Brooks Range, Alaska (copper, precious metals) W. P. Brosgé (M) TOPICAL INVESTIGATIONS IN PROGRESS Heavy metals——Continued District studies—Continued Base and precious metals—Continued *Central City-Georgetown area, Colorado, including studies of the Precambrian history of the Front Range (base, precious, and radioactive metals) P. K. Sims (D) Volcanic and economic geology of the Creede caldera, Colorado (base and precious metals, fluorspar) T. A. Steven (D) *Tenmile Range, including the Kokomo mining district, Colorado (base and precious metals) A. H. Koschmann (D) *San Francisco Mountains, Utah (base metals, tungsten) D. M. Lemmon (M) ‘Antler Peak quadrangle, Nevada (base and precious metals) R. J. Roberts (M) ‘Eureka County, Nevada (base and precious metals) R. J. Roberts (M) *Boulder batholith area, Montana (base, precious, and radioactive metals) M. R. Klepper (W) *East Tennessee zinc studies A. L. Brokaw (D) Origin and depositional control of some Tennessee and Virginia zinc deposits H. Wedow, Jr. (Knoxville, Tenn.) *Wisconsin zinc-lead mining district J. W. Whitlow (D) *Stratigraphy of the lead-zinc district near Dubuque, Iowa J. W. Whitlow (W) ‘Lead deposits of southeastern Missouri ’1‘. H. Kiilsgaard (W) Tri-State lead-zinc district, Oklahoma, Missouri, Kansas E. T. McKnight (W) ‘Holy Cross quadrangle, Colorado, and the Colorado min- eral belt (lead, zinc, silver, copper, gold) 0. Tweto (D) ‘Minturn quadrangle, Colorado (zinc, silver, copper, lead, gold) T. S. Lovering (D) *Rico district, Colorado (lead, zinc, silver) E. ’1‘. McKnight (W) *San Juan mining area, Colorado, including detailed study of the Silverton Caldera (lead, zinc, silver, gold, copper) R. G. Luedke (W) ‘Alta quadrangle, Utah (lead, silver, phosphate rock) M. D. Crittenden, Jr. (M) ‘East Tintic lead-zinc district, Utah, including extensive geochemical studies H. T. Morris (M) ‘Eureka area, Nevada (zinc, lead, silver, gold) T. B. Nolan (W) Ione quadrange, Nevada (lead, quicksilver, tungsten) C. J. Vitaliano (Bloomington, Ind.) Ore deposits of the Coeur d’Alene mining district, Idaho (lead, zinc, silver) V. C. Fryklund, Jr. (Spokane, Wash.) A—141 Heavy metals—Continued District studies—Continued Base and precious metals—Continued ‘General geology of the Coeur d’Alene mining district, Idaho (lead, zinc, silver) A. B. Griggs (M) *New York Butte quadrangle, California (lead-zinc) W. C. Smith (M) *Panamint Butte quadrangle, California, including special geochemical studies (lead-silver) W. E. Hall (W) *Metaline lead-zinc district, Washington M. G. Dings (D) *Stevens County, Washington, lead-zinc district R. G. Yates (M) *Mt. Diablo area, California (quicksilver, copper, gold, silver) E. H. Pampeyan (M) *Ochoco Reservation, Lookout Mountain, Eagle Rock, and Post quadrangles, Oregon (quicksilver) A. 0. Waters (Baltimore, Md.) "Lower Kuskokwim-Bristol Bay region, Alaska (quick— silver, antimony, zinc) J. M. Hoare (M) Quicksilver deposits, southwestern Alaska E. M. MacKevett, Jr. (M) ‘Nome C—1 and D—l quadrangles, Alaska (gold) 0. L. Hummel (M) ‘Tofty placer district, Alaska (gold, tin) D. M. Hopkins (M) ”Regional geology and mineral resources, southeastern Alaska R. A. Loney (M) Seward Peninsula tin investigations, Alaska P. L. Killeen (W) Commodity and topical studies: Mineral resource information and research H. Kirkemo (W) U.S. Mineral Resource maps W. L. Newman (W) Mineral exploration, northwestern United States D. R. MacLaren (Spokane, Wash.) Resource study and appraisal of ferrous and ferro-alloy metals T. P. Thayer (W) Resource study and appraisal of base and precious metals A. R. Kinkel, Jr. (W) Resources and geochemistry of rare-earth elements J. W. Adams (D) Refractory metals resources V. C. Fryklund, Jr. (Spokane, Wash.) Tantalum-niobium resources of the United States R. L. Parker (D) Western oxidized zinc deposits A. V. Heyl (W) Origin of the Mississippi Valley type ore deposits A. V. Heyl (W) Massive sulfide deposits A. R. Kinkel, Jr. (W) Alaskan metallogenic provinces C. L. Sainsbury (M) Miscellaneous mineral resource investigations, Alaska E. M. MacKevett, Jr. (M) A—142 Light metals and industrial minerals: District studies: Titaniferous black sands in Upper Cretaceous rocks, Wyoming R. S. Houston (Laramie, Wyo.) *Marysvale district, Utah (alunite) R. L. Parker (D) *McFadden Peak and Blue House Mountain quadrangles, Arizona (asbestos) A. F. Shride (D) *Talc and asbestos deposits of north-central Vermont W. M. Cady (Montpelier, Vt.) Barite deposits of Arkansas D. A. Brobst (D) Bauxite deposits of the southeastern States E. F. Overstreet (W) Aeromagnetic studies in the Newport, Arkansas, and Ozark bauxite areas A. Jespersen (W) ‘Greenacres quadrangle, Washington-Idaho (high-alumina clays) P. L. Weis (Spokane, Wash.) High-alumina weathered basalt on Kauai, Hawaii S. H. Patterson (W) Clay deposits of Maryland M. M. Knechtel (W) Clay deposits of the Olive Hill bed of eastern Kentucky J. W. Hosterman (W) Clay studies, Colorado Plateau L. G. Schultz (D) ‘Lake George district, Colorado (beryllium) C. C. Hawley (D) Fluorspar deposits of northwestern Kentucky R. D. Trace (Princeton, Ky.) *Salem quadrangle, Kentucky (fluorspar) R. D. Trace (Princeton, Ky.) ‘Poncha Springs and Saguache quadrangles, Colorado (fluorspar) R. E. Van Alstine (W) Thomas and Dugway Ranges, Utah (fluorspar-beryllium) M. H. Staatz (D) *Beatty area, Nevada (fluorite, bentonite, gold, silver) H. R. Cornwall (M) *Western Mojave Desert, California (boron) T. W. Dibblee, Jr. (M) *Furnace Creek area, California (boron) J. F. McAllister (M) Origin of the borate-bearing marsh deposits of California, Oregon, and Nevada (boron) W. C. Smith (M) ‘Geology and origin of the saline deposits of Searles Lake, California G. I. Smith (M) Potash and other saline deposits of the Carlsbad) area, New Mexico 0. L. Jones (M) *Heceta-Tuxekan area, Alaska (high-calcium limestone) G. D. Eberlein (M) *Chewelah area, Washington (magnesite) I. Campbell (San Francisco, Calif.) *Hunters quadrangle, Washington (magnesite, tungsten, base metals, barite) A. B. Campbell (D) GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Light metals and industrial minerals—Continued District studies—Continued Pegmatites of the Spruce Pine and Franklin-Sylva dis- tricts, North Carolina F. G. Lesure (Knoxville, Tenn.) *Geologic setting of the Spruce Pine pegmatite district, North Carolina (mica, feldspar) D. A. Brobst (D) *Southern Black Hills, South Dakota (pegmatite min- erals) J. J. Norton (W) ‘Pegmatites of the Custer district, South Dakota J. A. Redden (Blacksburg, Va.) *Structure and metamorphism, Hill City quadrangle, South Dakota (pegmatite minerals) J. C. Ratté (D) Phosphate deposits of northern Florida G. H. Espenshade (W) *Florida land-pebble phosphate deposits J. B. Cathcart (D) Stratigraphy and resources of the Phosphoria formation in Idaho (phosphate, minor elements) V. E. McKelvey (W) *Aspen Range-Dry Ridge area, Idaho (phosphate) V. E. McKelvey (W) *Soda Springs quadrangle, Idaho, including studies of the Bannock thrust zone (phosphate) F. C. Armstrong (Spokane, Wash.) Stratigraphy and resources of Permian rocks in western Wyoming (phosphate, minor elements) R. P. Sheldon (D) Phosphate deposits of south-central Montana R. W. Swanson (Spokane, Wash.) Stratigraphy and resources of the Phosphoria and Park City formations in Utah and Nevada (phosphate, minor elements) K. M. Tagg (M) Commodity and topical studies 2 Resource study and appraisal, light metals and industrial minerals J. J. Norton (W) Resources and geochemistry of selenium in the United States D. F. Davidson (D) Phosphate reserves, Southeastern United States J. B. Cathcart (D) Geochemistry and petrology of western phosphate de- posits R. A. Gulbrandsen (M) Radioactive minerals: District studies: Geology of the Piedmont region of the Southeastern States (monazite) W. C. Overstreet (W) ‘Shelby quadrangle (monazite) W. C. Overstreet (W) ‘Radioactive placer deposits of central Idaho D. L. Schmidt (Seattle, Wash.) *Powderhorn area, Gunnison County, Colorado (thorium) J. C. Olson (D) *Wet Mountains, Colorado (thorium, base and precious metals) M. R. Brock (W) TOPICAL INVE‘SVI'IGATIONS IN PROGRESS Radioactive minerals—Continued District studies—Continued Selected studies of uranium deposits in Pennsylvania H. Klemic (W) ‘Lehighton quadrangle, Pennsylvania (uranium) H. Klemic (W) Mineralogy of uranium-bearing rocks in Karnes and Duval Counties, Texas A. D. Weeks (“7) ‘Harding County, South Dakota, and adjacent areas (uraniferous lignibe) G. N. Pipiringos (D) *Western Red Desert area, Wyoming (uranium in coal) G. N. Pipiringos (D) *Southern Black Hills, South Dakota (uranium) G. B. Gott (D) Regional gravity studies in uranium geology, Black Hills area R. M. Hazelwood (D) *Regional stratigraphic study of the Inyan Kara group, Black Hills, Wyoming (uranium) W. J. Mapel (D) Uranium and phosphate in the Green River forma- tion, Wyoming W. R. Keefer (Laramie, Wyo.) *Baggs area, Wyoming and Colorado (uranium) G. E. Prichard (D) ‘Crooks Gap area, Fremont County, Wyoming (uranium) J. G. Stephens (D) ‘Gas Hills district, Wyoming (uranium) H. D. Zeller (D) *Hiland—Clarkson Hills area, Wyoming (uranium) E. 1. Rich (M) ‘Pumpkin Buttes area, Powder River Basin, Wyoming (uranium) W. N. Sharp (D) ‘Southern Powder River Basin, Wyoming (uranium) W. N. Sharp (D) Shirley basin area, Wyoming (uranium) E. N. Harshman (D) *Sborm Hill quadrangle, Wyoming (uranium) G. A. Izett (D) *Uranium deposits in the Front Range, Colorado P. K. Sims (D) "Compilation of Colorado Plateau geologic maps (ura- nium, vanadium) D. G. Wyant (D) Colorado Plateau botanical prospecting studies F. J. Kleinhampl (M) Triassic stratigraphy and lithology of the Colorado Plateau (uranium, copper) J. H. Stewart (D) San Rafael group (uranium) J. C. Wright (D) ‘Bull Canyon district, Colorado (vanadium, uranium) C. H. Roach (D) Exploration for uranium deposits in the Gypsum Val- ley district, Colorado C. F. Withington (W) *Klondike Ridge area, Colorado (uranium, copper, man- ganese, salines) J. D. Vogel (D) stratigraphy, Colorado Plateau A—143 Radioactive minerals—Continued District studies—Continued ‘Maybell—Lay area, Moffat County, Colorado (uranium) M. J. Bergin (W) *Ralston Buttes, Colorado (uranium) D. M. Sheridan (D) *Western San Juan Mountains, vanadium, gold) A. L. Bush (W) *Slick Rock district, Colorado (uranium, vanadium) D. R. Shawe (D) Uravan district, Colorado (vanadium, uranium) R. L. Boardman (W) *Ute Mountains, Colorado (uranium, vanadium) E. B. Ekren (D) Regional relations of the uranium deposits of north- western New Mexico L. S. Hilpert (Salt Lake City, Utah) Ambrosia Lake district, New Mexico (uranium) H. C. Granger (D) *Grants area, New Mexico (uranium) R. E. Thaden (Columbia, Ky.) Mineralogy of uranium-bearing rocks in the Grants area, New Mexico A. D. Weeks (W) ‘Laguna district, New Mexico (uranium) R. H. Moench (D) *Tucumcari-Sabinoso area, New Mexico (uranium) R. L. Griggs (D) *Abajo Mountains, Utah (uranium, vanadium) I. J. Witkind (D) ‘Circle Cliffs area, Utah (uranium) E. S. Davidson (Tucson, Ariz.) *Elk Ridge area, Utah (uranium) R. Q. Lewis (D) *Deer Flat area, White Canyon district, Utah (ura- nium, copper) T. L. Finnell (D) *La Sal area, Utah-Colorado (uranium, vanadium) W. D. Carter (Santiago, Chile) ‘Lisbon Valley area, Utah-Colorado (uranium, dium, copper) G. W. Weir (M) *Moab-Interriver area, east-central Utah (uranium) E. N. Hinrichs (D) *Orange Cliffs area, Utah (uranium) F. A. McKeown (D) *Sage Plain area, Utah (uranium and vanadium) L. C. Huff (D) Uranium ore controls of the San Rafael Swell, Utah 0. C. Hawley (D) *White Canyon area, Utah (uranium, copper) R. E. Thaden (D) Studies of uranium deposits in Arizona H. C. Granger (D) ‘Carrizo Mountains area, Arizona-New Mexico (ura— nium) J. D. Strobell (D) Uranium deposits of the Dripping Spring quartzite of southeastern Arizona H. C. Granger (D) Colorado (uranium, vana- A—144 Radioactive minerals—Continued District studies—Continued ‘East Vermillion Cliffs vanadium) R. G. Peterson (Boston, Mass.) ‘Mt. Spokane quadrangle, Washington (uranium) A. E. Weissenborn (Spokane, Wash.) *Turtle Lake quadrangle, Washington (uranium) G. E. Becraft (D) Commodity and topical studies : Resource studies and appraisals of radioactive raw materials A. P. Butler (D) Geology of monazite W. C. Overstreet (W) Uranium deposits in sandstone W. I. Finch (D) Processes of formation and redistribution of uranium deposits K. G. Bell , Relative concentrations of chemical elements in rocks and ore deposits of the Colorado Plateau (uranium, vanadium, copper) A. T. Miesch (D) Uranium-vanadium deposits in sandstone, with emphasis on the Colorado Plateau R. P. Fischer (D) Uranium in natural waters P. W. Fix (W) Trace elements in rocks of Pennsylvanian age (uranium, phosphate) W. Danilchik (Quetta, Pakistan) Uranium-thorium reconnaissance, Alaska E. M. MacKevett, Jr. (M) Fuels: District studies: \Petroleum and natural gas: *Stratigraphy of the Dunkirk and related beds in the Penn Yan and Keuka Lake quadrangles, New York (oil and gas) M. J. Bergin (W) ‘Stratigraphy of the Dunkirk and related beds, in the Bath and Woodhull quadrangles, New York (oil and gas) J. F. Pepper (New Philadelphia, Ohio) *Northern Arkansas oil and gas investigations, Arkansas E. E. Glick (D) Central Nebraska basin (oil and gas) G. E. Prichard (D) Subsurface geology of Dakota sandstone, Colorado and Nebraska (oil and gas) N. W. Bass (D) Paleozoic stratigraphy of the Sedgwick Basin, Kansas (oil and gas) W. L. Adkison (Lawrence, Kans.) *Shawnee County, Kansas (oil and gas) W. D. Johnson, Jr. (Lawrence, Kans.) ‘Wilson County, Kansas (oil and gas) H. C. Wagner (M) McAlester Basin, Oklahoma (oil and gas) S. E. Frezon (D) Anadarko Basin, Oklahoma and Texas (oil and gas) W. L. Adkison (Lawrence, Kans.) area, Arizona (uranium, GEOLOGICAL SURVEY RESEARCH 196l—SYNOPSIS OF RESULTS Fuels—Continued District studies—Continued Petroleum and natural gas—Continued *Wayland quadrangle, Texas (oil and gas investigations) D. A. Myers (D) *Franklin Mountains, New Mexico and Texas (petroleum) R. L. Harbour (D) Oil and gas fields, New Mexico D. 0. Duncan (W) Williston Basin oil and gas studies, Wyoming, Montana, North Dakota, South Dakota C. A. Sandberg (D) *Geology of the Winnett-Mosby area, Montana (oil and gas) W. D. Johnson, Jr. (Lawrence, Kans.) ‘Beaver Divide area, Wyoming (oil and gas) F. B. Van Houten (Princeton, NJ.) *Crowheart Butte area, Wyoming (oil and gas) J. F. Murphy (D) ‘Shotgun Butte, Wyoming (oil and gas) W. R. Keefer (Laramie, Wyo.) *Whalen-Wheatland area, Wyoming (oil and gas) L. W. McGrew (Laramie, Wyo.) Regional geology of the Wind River Basin, Wyoming (oil and gas) W. R. Keefer (Laramie, Wyo.) *Fuels potential of the Navajo Reservation, Arizona and Utah R. B. O’Sullivan (D) ‘Eastern Los Angeles basin, California (petroleum) J. E. ‘Schoellhamer (M) ‘Southeastern Ventura Basin, California (petroleum) E. L. Winterer (Los Angeles, Calif.) ‘Northwest Sacramento Valley, California (petroleum) R. D. Brown, Jr. (M) *Anlauf and Drain quadrangles, Oregon (oil and gas) L. Hoover (W) *‘Nelchina area, Alaska (petroleum) A. Grantz (M) *Iniskin-Tuxedni region, Alaska (petroleum) R. L. Detterman (M) "Gqu of Alaska province, Alaska (petroleum) D. J. Miller (M) "Lower Yukon-Koyukuk area, Alaska (petroleum) W. W'. Patton, Jr. (M) "Northern Alaska petroleum investigations G. Gryc (W) Coal: *Warrior quadrangle, Alabama (coal) W. C. Culbertson (D) Coal resources of Alabama W. C. Culbertson (D) *Ivydell, Pioneer, Jellico \Vest, and Ketchen quadrangles, Tennessee (coal) K. J. Englund (W) *Allegany County, Maryland (coal) W. deWitt, Jr. (W) ‘Bituminous coal resources of Pennsylvania E. D. Patterson (W) Washington County, Pennsylvania (coal) H. Berryhill, Jr. (D) *Southern anthracite field, Pennsylvania G. H. Wood, Jr. (W) TOPICAL INVESTIGATIONS IN PROGRESS A—145 Fuels—Continued District studies—Continued Coal—Continued ‘Western middle anthracite coal field, Pennsylvania H. H. Arndt (W) *Geology and coal resources of Belmont County, Ohio H. L. Berryhill, Jr. (D) *Eastern Kentucky coal investigations, Kentucky J. W. Huddle (W) *Ft. Smith district, Arkansas and Oklahoma (coal and gas) '1‘. A. Hendricks (D) *Arkansas Basin coal investigations B. R. Haley (D) ‘Animas River area, Colorado and New Mexico (coal, oil, and gas) H. Barnes (D) *Carbondale coal field, Colorado J. R. Donnell (D) *Eastern North Park, Colorado (coal, oil, and gas) D. M. Kinney (W) ’Western North Park, Colorado (coal, 'oil, and gas) W. J. Hail (D) ‘Trinidad coal fleld, Colorado R. B. Johnson (D) *Raton Basin coking coal, New Mexico G. H. Dixon (M) *East side San Juan Basin, New Mexico (coal, oil and gas) C. H. Dane (W) *Cedar Mountain quadrangle, Iron County, Utah (coal) P. Averitt (D) *Southern Kolob Terrace coal field, Utah W. B. Cashion (D) *Geology of the Livingston-Trail Creek area, Montana (coal) A. E. Roberts (D) Coal resources of Washington H. D. Gower (M) ‘Maple Valley, Hobart and Cumberland quadrangles, King County, Washington (coal) J. D. Vine (M) ‘Beluga—Yentna area, Alaska (coal) F. F. Barnes (M) *Matanuska coal field, Alaska F. F. Barnes (M) ‘Matanuska stratigraphic studies, Alaska (coal) A. Grantz (M) *Nenana coal investigations, Alaska C. Wahrhaftig (M) .Oil shale: "Oil shale investigations in Colorado D. C. Duncan (W) *Grand-Battlement Mesa oil-shale, Colorado J. R. Donnell (D) *Uinta Basin oil shale, Utah W. B. Cashion (D) ‘Green River formation, Sweetwater County, Wyoming (oil shale, salines) W. C. Culbertson (D) Resource studies: Fuel resource studies D. 0. Duncan (W) Geology of the continental shelves J. F. Pepper (New Philadelphia, Ohio) Fuels—Continued Resource studies—Continued Synthesis of geologic data on Atlantic Coastal Plain and Continental Shelf J. E. Johnston (W) Water: Regional and district studies: Columbia River basalt hydrology R. C. N ewcomb (g, Portland, Oreg.) Limestone terrane hydrology W. J'. Powell (g, Tuscaloosa, Ala.) Water—supply exploration on the public domain (Western States) G. G. Parker (h, D) Hydrologic effect of urbanization A. O. Waananen (h, M) North Pacific Coast area (surface water) E. E. Harris (s, M) Local floods, Alabama L. B. Peirce (s, Montgomery, Ala.) Rillito basin, Arizona (surface water) J. J. Ligner (s, Tucson, Ariz.) Low-flow gaging, Arkansas J. D. Warren (s, Fort Smith, Ark.) Flood investigations, Arkansas R. C. Christensen (s, Fort Smith, Ark.) Floods from small areas in California L. E. Young (s, M) lscambia and Santa Rosa Counties, Florida (surface water) R. H. Musgrove (s, Ocala, Fla.) Polk County, Florida (surface water) R. C. Heath (s, Ocala, Fla.) Drought of 1954—56 in Florida R. W. Pride (s, Ocala, Fla.) Hillsborough River floods of 1960, Florida R. W. Pride (s, Ocala, Fla.) St. Johns, Flagler, and Putnam Counties, Florida (sur- face water) W. E. Kenner (s, Ocala, Fla.) Everglades National Park (surface water) J. H. Hartwell (s, Ocala, Fla.) Green Swamp area, Florida (surface water) R. W. Pride (s, Ocala, Fla.) Flood gaging, Georgia C. M. Bunch (s, Atlanta, Ga.) Lake mapping and stabilization, Indiana (surface water) D. C. Perkins (s, Indianapolis, Ind.) Floods from small areas, Iowa H. H. Schwob (s, Iowa City, Iowa) Eastern Kentucky (surface water) G. A. Kirkpatrick (s, Louisville, Ky.) Flood investigations, Louisiana L. V. Page (s, Baton Rouge, La.) Rifle River basin, Michigan (surface water) R. W. Larson (s, Lansing, Mich.) North Branch Clinton River basin, Michigan (surface water) S. W. Wiitala (s, Lansing, Mich.) Sloan and Deer Creek basins, Michigan (surface water) L. E. Stoimenoff (s, Lansing, Mich.) A—146 GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Water—Continued Regional and district studies—Continued Paleontology : Systematic paleontology: Floods from small basins, Mississippi K. V. Wilson (s, Jackson, Miss.) Flood investigations on small areas, Missouri E. H. Sandhaus (s, Rolla, Mo.) Natural flow appraisals, Montana (surface water) W. A. Blenkarn (s, Helena, Mont.) Floods from small areas, Montana F. C. Boner (5; Helena, Mont.) Peak discharges from small areas, Nebraska E. W. Beckman (s, Lincoln, Nebr.) Hydrology of a portion of the Humboldt River Valley T. W. Robinson (h, M) Flood and base-flow gaging, New Jersey E. G. Miller (s, Trenton, NJ.) Babylon-Islip area, New York (surface water) E. J. Pluhowski (s, Albany, N.Y.) Small streams, New York (surface water) 0. P. Hunt (s, Albany, N.Y.) Flood and low-flow gaging, Rockland County G. R. Ayer (5, Albany, N.Y.) Flood gaging, North Carolina H. G. Hinson (s, Raleigh, N.C.) Peak discharges from small areas, North Dakota 0. A. Crosby (s, Bismarck, N. Dak.) Flood investigations, Puerto Rico H. H. Barnes (s, Atlanta, Ga.) Puerto Rico (surface water) D. B. Bogart (s, San Juan, Puerto Rico) Flood gaging, South Carolina W. W. Evett (s, Columbia, SC.) Peak discharges from small areas, South Dakota R. E. West (s, Pierre, S. Dak.) Brazos River saline investigations J. O. Joerns (s, Austin, Tex.) Flood gaging, Utah V. K. Berwick (s, Salt Lake City, Utah) Flood investigations, Virginia C. W. Lingham (s, Charlottesville, Va.) Nooksack River basin, Washington (water) E. G. Bailey (s, Tacoma, Wash.) Kitsap Peninsula, Washington (surface water) E. G. Bailey (s, Tacoma, Wash.) Tutuila, American Samoa (surface water) H. H. Hudson (s, Honolulu, Hawaii) Water use : Water use in the United States, 1960 K. E. MacKichan (h, W) Water resources of entire states K. E. MacKichan (h, W) Water resources of selected industrial areas (nation- wide) 0. D. Mussey (11, W) Water requirements of selected industries (nationwide) 10. D. Mussey (h, W) Water requirements of the magnesium industry 0. D. Mussey (11, W) Water requirements of the petroleum industry 0. D. Mussey (h, W) Water requirements of the rubber industry 0. D. Mussey (h, W) Water requirements of the steel industry 0. D. Mussey (h, W) Fossil wood and general palebotany R. A. Scott (D) Paleozoic paleobotany S. H. Mamay (W) Coal lithology and paleobotany J. M. Schopf (Columbus, Ohio) Upper Paleozoic floral zones and provinces C. B. Read (Albuquerque, N. Mex.) Lower Pennsylvanian floras of Illinois and adjacent States C. B. Read (Albuquerque, N. Mex.) Stratigraphic significance of the genus Tempskya in southwestern New Mexico C. B. Read (Albuquerque, N. Mex.) Post-Paleozoic pollen and spores E. B. Leopold (D) Diatom studies K. E. Lohman (W) Tertiary paleobotanical studies J. A. Wolfe (M) Marine paleoecology P. E. Cloud, Jr. (W) Vertebrate paleontologic studies, Western United States G. E. Lewis (D) Vertebrate faunas, Martha’s Vineyard, Massachusetts F. C. Whitmore, Jr. (W) Vertebrate paleontology, Big Bone Lick, Kentucky F. C. Whitmore, Jr. (W) Vertebrate faunas, Ishigaki, Ryukyu Islands F. C. Whitmore, Jr. (W) Lower Paleozoic corals W. A. Oliver, Jr. (W) Upper Paleozoic corals W. J. Sando (W) Bryozoans and corals, Western United States H. Duncan (W) ' Carboniferous cephalopods M. Gordon (M) Paleozoic gastropods E. L. Yochelson (W) Cenozoic gastropods and pelecypods, Pacific Islands F. S. MacNeil (M) Oligocene gastropods and pelecypods, Mississippi F. S. MacNeil (M) Cenozoic mollusks, Oregon E. J. Moore (M) Cenozoic nonmarine mollusks D. W. Taylor (W) Cenozoic mollusks, Atlantic and Gulf Coastal Plains D. Wilson (W) Cenozoic mollusks, Pacific Islands H. S. Ladd (W) Cenozoic mollusks, Alaska F. S. MacNeil (M) Lower Paleozoic ostracodes J. M. Berdan (W) Ostracodes, Upper Paleozoic and younger I. G. Sohn (W) Charophytes and nonmarine ostracodes R. E. Peck (W) Upper Paleozoic fusulines L. G. Henbest (W) TOPICAL INVESTIGATIONS IN PROGRESS A—147 Paleontology—Continued Paleontology—Continued Systematic paleontology—Continued Stratigraphic paleontology—Continued Post Paleozoic larger Foram inifera R. C. Douglass (W) Foraminifera of the Lodo formation, central California M. C. Israelsky (M) Fusuline Foraminifera of Nevada R. C. Douglass (W) Cretaceous Foraminifera of the Nelchina area, Alaska H. R. Bergquist (W) Upper Cretaceous Foraminifera M. R. Todd (W) Cenozoic Foraminifera, Colorado Desert P. J. Smith (M) Cenozoic Foraminifera, Pacific Ocean and Islands M. R. Todd (W) Cenozoic faunas, Caribbean area W. P. Woodring (W) Recent Foraminifera, Central America P. J. Smith (M) Ecology of Foraminifera M. R. Todd (W) Stratigraphic paleontology: Cambrian faunas and stratigraphy A. R. Palmer (W) Lower Paleozoic stratigraphic paleontology, Eastern United States R. B. Neuman (W) Ordovician stratigraphic paleontology of the Great Basin and Rocky Mountains R. J. Ross, Jr. (D) Subsurface Paleozoic rocks of Florida J. M. Berd-an (W) Silurian and Devonian stratigraphic paleontology of the Great Basin and Pacific Coast 0. W. Merriam (W) Midcontinent Devonian investigations E. R. Landis (D) Upper Paleozoic stratigraphic paleontology, Western United States J. T. Dutro, Jr. (W) Stratigraphy of the Belt series C. P. Ross (D) Stratigraphy and paleontology of the Pierre shale, Front Range area, Colorado and Wyoming W. A. Cobban and G. R. Scott (D) Stratigraphic studies, Colorado Plateau (uranium, vanadium) L. C. Craig (D) *Geology and paleontology of the Cuyama Valley area, California J. G. Vedder (M) Mesozoic stratigraphic paleontology, Atlantic and Gulf coasts N. F. Sohl (W) Mesozoic stratigraphic paleontology of northwestern Montana W. A. Cobban (D) Mesozoic stratigraphic paleontology, Pacific Coast D. L. Jones (M) Lower Mesozoic stratigraphy and paleontology, Humboldt Range, Nevada N. J. Silberling (M) Stratigraphy of the Belt series—Continued Cordilleran Triassic faunas and stratigraphy N. J. Silberling (M) Jurassic stratigraphic paleontology of North America R. W. Imlay (W) Cretaceous stratigraphy and paleontology, western in- terior United States W. A. Cobban (D) Cenozoic stratigraphic paleontology D. Wilson (W) Stratigraphy of the Trent marl and related units P. M. Brown (g, Raleigh, NC.) Geomorphology and plant ecology: The effects of exposure on slope morphology R. F. Hadley (h, D) Use of plant species or communities as indicators of soil moisture availability F. A. Branson (h, D) Interrelationships between ion distribution and water movement in soils and the associated vegetation R. F. Miller (h, D) Vegetation map of Alaska L. A. Spetzman (W) Pacific Islands vegetation F. R. Fosberg (W) Meandering valleys and related questions of Pleistocene chronology G. H. Dury (w, W) The hydraulic geometry of a small tidal estuary L. B. Leopold (w, W) Evolution of Black Earth Creek and Mounds Creek, Wisconsin G. H. Dury (w, W) Clastic sedimentation in a bolson environment L. K. Lustig (q, Boston, Mass.) A study of stream gravel and gravel bars L. B. Leopold (w, W) . Particle movement and channel scour and fill of an ephemeral arroyo near Santa Fe, N. Mex. L. B. Leopold (w, W) Bankfull discharge, with particular reference to certain channel dimensions G. H. Dury (w, W) Exploration of valley fllls by seismic refraction G. H. Dury (w, W) Channel geometry studies, Iowa (surface water) H. H. Schwob (s, Iowa City, Iowa) Stream profiles, Alabama (surface water) L. B. Peirce (s, Montgomery, Ala.) Flood profiles, Iowa H. H. Schwob (s, Iowa City, Iowa) Geomorphology of glacier streams R. K. Fahnestock (h, Fort Collins, Colo.) Solution subsidence of a limestone terrane in southwest Georgia S. M. Herrick (g, Atlanta, Ga.) Hydrologic zonation of limestone formations H. E. LeGrand (w, W) Geomorphology in relation to ground water H. E. LeGrand (w, W) A—148 Geomorphology and plant ecology—Continued Diagenesis and hydrologic history of the Tertiary lime- stone of North Carolina H. E. LeGrand (w, W) River systems studies M. T. Thomson (s, Atlanta, Ga.) Relation of geology to low flow, Georgia 0. J. Cosner (s, Atlanta, Ga.) Basic research in vegetation and hydrology R. S. Sigafoos (h, W) Glaciology and glacial geology: Recognition of late glacial substages in New England and New York J. E. Upson (g, Mineola, NY.) Glacialogical research M. F. Meier (h, Tacoma, Wash.) Permafrost studies: Distribution and general characteristics of permafrost W. E. Davies (W) Relationship of permafrost to ground water J. R. Williams (g, Anchorage, Alaska) Arctic ice and permafrost studies, Alaska A. H. Lachenbruch (M) Origin and stratigraphy of ground ice in central Alaska T. L. Péwé (College, Alaska) Paleomagnetism : Investigation of remanent magnetization of rocks R. R. Doell (M) Physical properties of rocks: Rock behavior at high temperature and pressure E. C. Robertson (W) Investigation of elastic and anelastic properties of earth materials L. Peselnick (W) Magnetic susceptibility of minerals F. E. Senftle (W) Measurement of magnetic properties of rocks W. E. Huflz' (W) Magnetic properties of rocks A. Griscom (W) Electrical properties of rocks C. J. Zablocki (D) Infrared and ultraviolet radiation studies R. M. Moxham (W) Rock deformation; Origin and mechanics of detachment faults W. G. Pierce (M) Impact metamorphism E. C. T. Chao (W) Experimental hyper-velocity impact studies H. J. Moore (M) Thermoluminescence and maSS physical properties 0. H. Roach (D) Diatremes, Navajo and Hopi Indian Reservations E. M. Shoemaker (M) Meteor Crater, Arizona E. M. Shoemaker (M) Sierra Madera, Texas E. M. Shoemaker (M) Geophysical exploration methods: Research in geophysical data interpretation using elec- tronic computers R. G. Henderson (W) GEOLOGICAL SURVEY RESEARCH lQGl—SYNOPSIS OF RESULTS Geophysical exploration methods—Continued Correlation of airborne radioactivity data and areal geology J. A. Pitkin (W) Polar charts for 3-dimensional magnetic anomalies R. G. Henderson (W) Geophysical interpretation aids 1. Roman (W) Telluric currents investigation D. Ploufi (D) Development of electromagnetic methods F. C. Frischknecht (D) Frequency analysis of seismograms S. W. Stewart (D) Seismic equipment R. E. Warrick (D) Thermistor studies C. H. Sandberg (M) Physical and chemical contrasts between uranium-bear- ing sandstones and contiguous sandstones G. E. Manger (W) Electronics laboratory W. W. Vaughn (D) Geophysical instrument shop R. Raspet (W) Measurement of background radiation : Aerial radiological monitoring surveys, Northeastern United States P. Popenoe (W) Aerial radiological monitoring surveys, Belvoir area, Vir- ginia and Maryland S. K. Neuschel (W) Aerial radiological monitoring surveys, Oak Ridge Na- tional Laboratory, Tennessee R. G. Bates (W) Aerial radiological monitoring surveys, Georgia Nuclear Aircraft Laboratory J. A. MacKallor (W) Aerial radiological monitoring surveys, Savannah River Plant, Georgia and South Carolina R. G. Schmidt (W) Aerial radiological monitoring surveys, Fort Worth, Texas J. A. Pitkin (W) Aerial radiological monitoring surveys, Los Angeles, California K. G. Books (W) Aerial radiological monitoring surveys, Nevada Test Site J. L. Menschke (W) Aerial radiological monitoring surveys, San Francisco, California J. A. Pitkin (W) Aerial radiological monitoring surveys, National Reactor Testing Station, Idaho R. G. Bates (W) Aerial radiological monitoring surveys, Hanford, Wash- ington R. G. Schmidt (W) Aerial radiological monitoring surveys, Alaska R. G. Bates (W) Propagation of seismic waves in porous media. J. A. daCosta (g, W) Chariot site, TOPICAL INVESTIGATIONS: IN PROGRESS A—149 Crustal studies : Thermal studies (earth temperatures) -.H. C. Spicer (W) Seismic investigations of continental crust W. H. Jackson (D) :Seismic pulse studies P. E. Byerly (D) Gravity map of the United States H. R. Joesting (W) Geologic studies of active seismic areas W. S. Twenhofel (D) Cross-country aeromagnetic profiles E. R. King (W) Aeromagnetic profiles over the Atlantic Continental Shelf and Slope E. R. King (W) Maine aeromagnetic surveys J. W. Allingham (W) *Electromagnetic and geologic mapping in Island Falls quadrangle, Maine F. C. Frischknecht (D) Gravity studies, northern Maine M. F. Kane (W) *Geophysical and geologic mapping in the Stratton quad- rangle, Maine A. Griscom (W) Geophysical studies of Appalachian structure E. R. King (W) Aeromagnetic studies, Concord-Denton area, North Carolina R. W. Johnson, Jr. (Knoxville, Tenn.) Central and Western North Carolina regional aeromag— netic survey R. W. Johnson, Jr. (Knoxville, Tenn.) Aeromagnetic studies, Middlesboro-Morristown area, Ten- nesseeKentucky-Virginia R. W. Johnson, Jr. (Knoxville, Tenn.) Aeromagnetic study of peridotite, Maynardville, Ten- messee R. W. Johnson, Jr. (Knoxville, Tenn.) Seismic survey for buried valleys in Ohio R. M. Hazlewood (D) Geophysical studies in the Lake Superior region G. D. Bath (M) *Texas coastal plain geophysical and geological studies D. H. Eargle (Austin, Tex.) Gravity studies, Yellowstone area H. L. Baldwin (D) Gravity profile of the southern Rocky Mountains, Colorado D. J. Stuart (D) Gravity studies, Snake River Plain, Idaho D. J. Stuart (D) Colorado Plateau regional geophysical studies H. R. Joesting (W) Geophysical studies in the Rowe-Mora area, New Mexico G. E. Andreasen (W) Great Basin geophysical studies D. R. Mabey (M) Gravity studies, California-Nevada region D. J. Stuart (D) Geophysical studies of Nevada Test Site R. A. Black (D) Gravity studies, Sierra Valley, California W. H. Jackson (D) 608400 O—-6L-—11 Crustal studies—Continued Gravity studies, southern Cascade Mountains, California L. C. Pakiser (D) Pacific Northwest geophysical studies W. E. Davis (W) Magnetic studies of Montana laccoliths R. G. Henderson (W) Aeromagnetic and gravity studies of the Boulder batho— lith, Montana W. E. Davis (M) Gravity and magnetic studies in western Montana W. T. Kinoshita (M) Gravity survey of western Washington D. J. Stuart (W) Aeromagnetic and gravity studies in west-central Oregon R. W. Bromery (W) Aeromagnetic surveys, Alaska G. E. Andreasen (W) Regional gravity surveys, Alaska D. F. Barnes (M) Geophysical studies in the Arctic Ocean G. V. Keller (D) Experimental geochemistry: Experimental geochemistry—hydrothermal silicate systems D. B. Stewart, D. R. Wones, and H. R. Shaw (W), and J. Hemley and P. Hostetler (D) Experimental geochemistry—metallic sulfides and sulfo- salt systems B. J. Skinner, E. H. Roseboom, Jr., P. B. Barton, Jr., P. M. Bethke, and P. Toulmin, III (W’) Hydrothermal solubility G W. Morey (W) Chemical composition of thermal waters in Yellowstone Park G. W. Morey (W) Solubilities of minerals in aqueous fluids C. A. Kinzer and P. B. Barton, Jr. (W), and J. Hemley and P. Hostetter (D) Fluid inclusions in minerals E. W. Roedder (W) Thermodynamic properties of minerals R. A. Robie, B. J. Skinner, P. B. Bartin, Jr., P. M. Bethke, and P. Toulmin, III (W) Experimental geochemistry—alkali and alkaline earth salt systems E-an Zen (W) Investigation of hydrothermal jasperoid T. G. Lovering (D) Phase relations in rocks and experimental systems F. Barker (W) Experimental studies on rock weathering and alteration J. J. Hemley (D) Processes afiecting solute composition and minor element distribution in lacustrine closed basins B. F. Jones (q, W) Mineralogy and crystal chemistry : Crystal chemistry D. E. Appleman (W) Experimental mineralogy and crystal chemistry—rock- forming silicate minerals D. E. Appleman (W) A—150 Mineralogy and crystal chemistry—Continued Experimental mineralogy and crystal chemistry—phos- phate minerals D. E. Appleman (W) Mineralogical studies and description of new minerals D. E. Appleman (\V) Mineralogical studies and description of new minerals— micas and chlorites M. D. Foster (W) Mineralogical studies and description of new chromium- bearing minerals C. Milton (W) Mineralogical studies and description of new vanadium- bearing minerals A. D. Weeks (W) Crystal chemistry of borate minerals J. R. Clark and C. L. Christ (W) Crystal chemistry of phosphate minerals M. E. Mrose (W) Crystal chemistry of uranium minerals H. T. Evans (W) Sedimentary mineralogy J. C. Hathaway (D) Mineralogic services A. D. Weeks (W) Mineralogic services and research T. Botinelly (D) Mineralogical services and research R. G. Coleman (M) Spatial distribution of chemical constituents in ground water, eastern United States XV. Back (g, W) Geochemistry of ground water in the Englishtown formation P. R. Seaber (g. Trenton, NJ.) Geochemical distribution of the elements: Geochemical distribution of elements M. Fleischer (W) Geochemical compilation of rock analyses M. Hooker (W) Minor elements in coal P. Zubovic (W') Dispersion pattern of minor elements related to igneous intrusions W. R. Griflitts (D) Geochemistry of minor elements E. S. Larsen, 3d (W) Uranium and thorium in magmatic diflerentiation E. S. Larsen, 3d (W) Chemical composition of sedimentary rocks H. A. Tourtelot (D) Mineral constituents in ground water J. H. Feth (g, M) Chemistry of hydrosolic metals in natural water J. D. Hem (q, D) Fluvial denudation in the United States. Phase 2.— Variance in water quality and environment F. H. Rainwater (q, W) Solute-solid relations in lacustrine closed basins of the alkali-carbonate type B. F. Jones (q, W) Occurence and distribution of strontium in natural water M. W. Skougstad (q, D) GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Petrology : Origin and characteristics of thermal and mineral waters D. E. White (W) Igneous rocks of southeastern United States C. Milton (W) Studies of welded tuff R. L. Smith (\V) Model studies of structures in sediments E. D. McKee (D) Porosity and density of sedimentary rocks G. E. Manger (W) ' Metamorphism and origin of mineral deposits, Gouv- erneur area, New York A. E. J. Engel (Pasadena, Calif.) *Petrology of the Manassa quadrangle, Virginia C. Milton (W) ‘Petrology of the Valles Mountains, New Mexico R. L. Smith (\V) Petrology and geochemistry of the Laramide intru- sives in the Colorado Front Range G. Phair (W) Petrology and geochemistry of the Boulder Creek batholith, Colorado Front Range G. Phair (W) Ore deposition at Creede, Colorado E. W. Roedder (W) Magmatic differention in calc—alkaline intrusives, Mt. Princeton area, Colorado P. Toulman III (W) \Vallrock alteration and its relation to thorium de— position in the Wet Mountains, Colorado G. Phair (W) Chemical and physical properties of the Pierre shale, Montana, North Dakota, South Dakota, Wyo- ming, and Nebraska H. A. Tourtelot (D) Lithologic studies, Colorado Plateau R. A. Cadigan (D) Mineralogy and geochemistry of the Green River for- mation, Wyoming 0. Milton (W) Geology and paleolimnology of the Green River for- mation, )Vyoming W. H. Bradley (W) *Petrology of the Bearpaw Mountains, Montana ‘V. T. Pecora (W) Carbonatite deposits, Montana \V. T. Pecora (W) *Petrology of the Wolf Creek area, Montana R. G. Schmidt (\V) Petrology and chromite resources of the Stillwater ultramafic complex, Montana E. D. Jackson (M) Petrology of volcanic rocks, Snake River Valley, Idaho H. A. Powers (D) *Metamorphism of the Orofino area, Idaho A. Hietanen (M) *Geochemistry and metamorphism of the Belt Series; Clark Fork and Packsaddle Mountain quad- rangles, Idaho and Montana J. E. Harrison (D) *Petrology of the Burney area, California G. A. Macdonald (Honolulu, Hawaii) TOPICAL INVESTIGATIONS IN PROGRESS Petrology—Continued Glaucophane schist terranes formation, California R. G. Coleman (M) ‘Petrology and Volcanism, Katmai National Monument, Alaska G. H. Curtis (M) . Geological, geochemical, and geophysical studies of Hawaiian volcanology J. P. Eaton (Hawaii) Hawaiian volcanoes, thermal and magnetic studies J. H. Swartz (W) Petrological services and research C. Milton (W) Sedimentary petrology laboratory H. A. Tourtelot (D) Organic geochemistry: Organic geochemistry and infrared analysis I. A. Breger (W) Organic substances in water W. L. Lamar (q, M) Isotope and nuclear studies: Nuclear irradiation C. M. Bunker (D) Geochronology: carbon-14 method M. Rubin (W) Geochronology; K/A and Rb/Sr methods H. Thomas (XV) Geochronology: lead-alpha ages of rocks T. W. Stern (W) Significance of lead-alpha age variation in batholiths of the Colorado Front Range D. Gottfried (W) Geochronology: lead-uranium ages of mineral deposits L. R. Stieft‘ (W) Radiogenic daughter products J. N. Rosholt (W) Isotope ratios in rocks and minerals I. Friedman (W) Oxygen isotope geothermometry H. L. James (M) Density comparison isotope ratios J. H. McCarthy, Jr. (D) Isotope fractionation in living organisms F. D. Sisler (W) Use of tritium in hydrologic studies 0. W. Carlston (g, W) Use of tritium in hydrologic studies L. L. Thatcher (q, W) Occurence and distribution of radioelements in water F. B. Barker ((1, D) Tritium in ground water in the Roswell Basin J. W. Hood (g, Albuquerque, N. Mex.) Tritium as a tracer in the Lake McMillan under- ground reservoir H. O. Reeder (g, Albuquerque, N. Mex.) Hydraulic and hydrologic studies: Textbook on ground-water geology A. N. Sayre (w, W) Bibliography on hydrology and sedimentation H.-C. Riggs (s, W) within the Franciscan method for determining oxygen A—151 Hydraulic and hydrologic studies—Continued Sources of foreign papers (water) V. M. Yevdjevich (s, W) Flow in smooth channels H_. J. Tracy (s, Atlanta, Ga.) Discharge characteristics of weirs and dams C. E. Kindsvater (s, Atlanta, Ga.) Direct Measurement of boundary channel flow R. W. Carter (s, W) Variation in velocity-head coefficient H. Hulsing (s, M) Depth-discharge relations in alluvial channels D. R. Dawdy (s, W) Tidal—flow measurement S. E. Rantz (s, M) Tidal-flow investigation R. A. Baltzer (s, Lansing, Mich.) Wave-height piezometric registration . W. W. Emmett (s, Atlanta, Ga.) Effect of channel roughness (water) H. J. Koloseus (s, Iowa City, Iowa) Directional permeability of marine sandstones R. R. Bennett (g, W) Source of base flow of streams F. A. Kilpatrick (s, Atlanta, Ga.) Effect of removing riparian vegetation, Cottonwood Wash, Arizona (water) J. E. Bowie (s, Tucson, Ariz.) Water-loss and -gain studies in California W. 0. Peterson (s, M) California coastal basins hydrology S. E. Rantz (s, M) Rainfall-runoff relations, Kentucky J. A. McCabe (s, Louisville, Ky.) Cadwell Brook, Massachusetts (surface water) G. K. Wood (s, Boston, Mass.) shear in open- Hydrologic investigations, small watersheds, Trinity, Brazos, Colorado, and San Antonio River basins, Texas W. H. Goines (s, Austin, Tex.) Hydrologic investigations, urban watershed, Austin. Texas A. E. Hulme (s, Austin, Tex.) Effect of changes in forest cover on streamflow F. M. Veatch (s, Tacoma, Wash.) General hydrology, West Virginia W. L. Doll (s. Charleston, W. Va.) Hydrologic interpretation of topographic features W. J. Schneider (s, W) Statistical techniques and appraisals N. C. Matalas (s, W) Roughness in alluvial channels and sediment transporta- tion D. B. Simons (q, Fort Collins, 0010.) Sediment transport parameters in sand bed streams J. K. Culbertson (q, Albuquerque, N. Mex.) Factors affecting sediment transport—graphical repre- sentation of factors affecting bed-material dis- charge of sand bed streams B. R. Colby (q,- Lincoln, Nebr.) A—152 Hydraulic and hydrologic studies—«Continued Influence of fine sediment on resistance to flow and sedi- ment transport in alluvial channels W. L. Hauschild (q, Fort Collins, Colo.) Effects of variable channel roughness and other factors on bed-load transport R. H. Taylor (q, Pasadena, Calif.) Transportation of sediment by the Mississippi River P. R. Jordan (q, Lincoln, Nebr.) Techniques for utilization of sediment reconnaissance data H. P. Gu‘y (q, W) Study of aggradation and degradation in stream channels S. A. Schumm (h, D) Evaluation of sediment barrier on Sheep Creek, Paria River Basin, near Tropic, Utah G. C. Lusby (h, D) Effects of particle size distribution on mechanics of flow in alluvial channels D. B. Simons (q, Fort Collins, Colo.) The effects of sediment characteristics on fluvial morphol- ogy hydraulics S. A. Schum (h, D) Theory of unsaturated flow H. E. Skibitzke (g, Phoenix, Ariz.) Unsaturated flow studies ‘V. O. Smith (g, W) Transient flow studies W. 0. Smith (g, W) Vadose flow through homogeneous and isotropic media W. N. Palmquist (g, D) Specific-yield research A. 1. Johnson (g, D) Analog model-unsaturated flow H. E. Skibitzke (g, Phoenix, Ariz.) Multiphase flow theory application R. W. Stallman (g, D) Effects of heterogeneity H. E. Skibitzke (g, Phoenix, Ariz.) Analog model research B. J. Bermes (g, Phoenix, Ariz.) Hydrologic analog model unit B. J. Bermes (g, Phoenix, Ariz.) Changes below dams M. G. \Volman (h, Baltimore, Md.) Laboratory study of the growth of meanders in open channels M. G. W'olman (h, Baltimore, Md.) Limnological problems: Physical characteristics of selected Florida lakes ‘V. E. Kenner (s, Ocala, Fla.) Thermal surveys, Lake Colorado City, Texas G. H. Hughes (s, San Angelo, Tex.) Evapotranspiration : Mechanics of evaporation G. E. Koberg (h, D) Evapotranspiration theory and measurement 0. E. Leppanen (h, Phoenix, Ariz.) Evapotranspiration study 0. E. Leppanen (h, Phoenix, Ariz.) Evaporation inventory G. E. Koberg (h, D) GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Evapotranspiration—Continued Study of water application and use on a range water spreader in northeast Montana F. A. Branson (h, D) Determination of evaporation coefficient for reservoirs in San Diego, California G. E. Koberg (h, D) Hydrologic effect of vegetation modification R. C. Culler (h, Tucson, Ariz.) Use of water by saltcedar in evapotranspirometer com- pared with energy budget and mass transfer com- putation (Buckeye) T. E. A. Van Hylckama (h, Phoenix, Ariz.) Hydrology of prairie potholes J. B. Shjeflo (h, D) Geology applied to construction and terrain problems: *Herndon quadrangle, Virginia (construction-site plan- ning) R. E. Eggleton (D) *Air Force Academy, Colorado (construction-site plan- ning) D. J. Varnes (D) *Black Canyon of the Gunnison River, Colorado (con- struction-site planning) W. R. Hansen (D) Engineering geology of the Roberts Tunnel, Colorado 0. S. Robinson (D) *Surflcial geology of the Oak City area, Utah (construc- tion-site planning) D. J. Varnes (D) *Upper Green River Valley, Utah (construction-site plan- ning) W. R. Hansen (D) *Fort Peck area, Montana (construction-site planning) H. D. Varnes (D) *Wolf Point area, Montana (construction-site planning) R. B. Colton (D) *Surflcial and engineering geology studies and construc— tion materials sources, Alaska T. L. Péwé (College, Alaska) Engineering soils map of Alaska T. N. V. Karlstrom (W) Rock types map of Alaska L. A. Vehle (W) Landform map of Alaska H. W. Coulter (W) *Surticial geology of the AnchorageMatanuska Glacier area (construction-site planning) T. N. V. Karlstrom (W) *Surficial geology of the Big Delta Army Test area, Alaska (construction-site planning) G. W. Holmes (W) *Surficial geology of the Big Delta-Fairbanks area, Alaska (construction-site planning) H. L. Foster (W) *Surficial geology of the lower Chitina Valley, Alaska (construction-site planning) L. A. Yehle (W) *Surficial geology of the northeastern Copper River basin, Alaska (construction—site planning) 0. J. Ferrians, Jr. (Glennallen, Alaska) *Surficial geology of the southeastern Copper River basin Alaska (construction-site planning) D. R. Nichols (W) TOPICAL INVESTIGATIONS IN PROGRESS Geology applied to construction and terrain problems—Con. *Surflcial geology of the southwestern Copper River basin, Alaska (construction—site planning) J. R. Williams (W) *Surficial geology of the eastern Denali Highway, Alaska (construction-site planning) D. R. Nichols (W) *Mt. Hayes D—3 and D—4 quadrangles, Alaska (construc- tion-site planning) T. L. Péwé (College, Alaska) *Surficial geology of the Johnson River district, Alaska (construction-site planning) H. L. Foster (W) “Surficial geology of the Kenai lowland, Alaska (construc- tion-site planning) T. N. V. Karlstrom (W) *Surflcial geology of the Seward-Portage Railroad Belt, Alaska (construction—site planning) T. N. V. Karlstrom (W) *Surficial geology of the Slana-Tok area, Alaska (con- struction-site planning) H. R. Schmoll (W) *Surficial geology of the Susitna-Maclaren River area, Alaska (construction~site planning) D. R. Nichols (W) “Engineering geology Alaska Florence Weber (College, Alaska) *Surficial geology of the Upper Tanana River, Alaska (construction-site planning) A. T. Fernald (W) *Surficial geology of the Valdez-Tiekel belt, Alaska (con- struction—site planning) H. W. Coulter (W) MEngineering geology of Yukon-Ko-yukuk lowland, Alaska F. R. Weber (College, Alaska) *Knoxville and vicinity, Tennessee (urban geology) J. M. Cattermole (D) *Omaha-Council Bluffs and vicinity, Nebraska and Iowa (urban geology) R. D. Miller (D) *Denver metropolitan area, Colorado (urban geology) R. M. Lindvall (D) *Golden quadrangle, Colorado (urban geology) R. Van Horne (D) *Morrison quadrangle, Colorado (urban geology) J. H. Smith (D) Pueblo and vicinity, Colorado (urban geology) G. R. Scott (D) *Great Falls area, Montana (urban geology and construc- tion-site planning) R. W. Lemke (D) *Surficial geology of the Beverly Hills, Venice, and Topanga quadrangles, Los Angeles, California (ur- ban geology) J. T. McGill (Los Angeles, Calif.) Malibu Beach quadrangle, California (urban geology) R. F. Yerkes (M) *San Francisco Bay area; San Francisco North quad- rangle, California (urban geology) J. Schlocker (M) *San Francisco Bay area; San Francisco South quad- rangle, California (urban geology) M. G. Bonilla (M) of Talkeetna-McGrath highway, A—153 Geology applied to construction and terrain problems—Con. *Oakland East quadrangle, California (urban geology) D. H. Radbruch (M) *Portland industrial area, Oregon and Washington (urban geology) D. E. Tn'mble (D) *Puget Sound Basin, Washington (urban geology and con- struction-site planning) D. R. Mullineaux (D) Engineering geologic studies of Seattle, Washington D. R. Mullineaux (D) Engineering problems related to rock failure: Deformation research D. J‘. Varnes (D) Geologic factors involved in subsidence A. S. Allen (W) Engineering geology laboratory .T. C. Nichols, Jr. (D) Earthquake investigations, Hebgen Lake, Montana J. B. Hadley (W) and I. J. Witkind (D) *Geologic factors related to coal mine bumps, Utah F. W. Osterwald (D) Osceola mudflow studies, Washington D. R. Crandell (D) Landslide studies in the Fort Randall Reservoir area, South Dakota H. D. Varnes (D) Erosion: Sea-cliff erosion studies C. A. Kaye (Boston, Mass.) General studies of erosion and sedimentation G. G. Parker (11, D) Study of the mechanics of hillslope erosion (S. A. Schumm (h, D) Study of channel flood-plain aggradation Tusayan Washes, Arizona .R. F. Hadley (h, D) Nuclear test-site studies: *Nuclear test-site evaluation, Chariot, Alaska G. D. Eberlein (M) *Engineering geology of Gnome Test Site, New Mexico L. M. Gard (D) *Nash Draw quadrangle, New Mexico (test-site evalua- tion) J. D. Vine (M) *Engineering geology of the Nevada Test Site area V. R. Wilmarth (D) Geologic and hydrologic environment of Tatum salt dome, Mississippi (test-site evaluation) XV. S. Twenhofel (D) Geophysical studies of Nevada Test Site R. A. Black (D) Analysis of hydrologic data : Use of precipitation records in extending streamflow data R. O. R. Martin (s, W) Automatic data processing W. L. Isherwood (s, W) Hydrologic atlas of Pacific Northwest W. D. Simons (11, Tacoma, Wash.) Study of precipitation runoff and sediment yield in Corn- field Wash, New Mexico D. E. Burkham (h, Albuquerque, N. Mex.) A—154 Analysis of hydrologic data—Continued Hydrologic regimen and volumetric analysis of Upper )Gila River C. T. Sumsion (g, Tucson, Ariz.) Hydrologic and hydraulic studies, Virginia C. W. Lingham (s, Charlottesville, Va.) Floods of January and February 1959, Ohio W. P. Cross (s, Columbus, Ohio) Flood-plain zoning, New Jersey R. H. Tice (s, Trenton, NJ.) Flood-frequency methods M. A. Benson (s, W) Extending small-area flood records, Alabama L. B. Peirce (s, Montgomery, Ala.) Effect of urbanization on peak discharge R. W. Carter (s, W) Ponds as runoff measuring devices R. Sloss (s, Baton Rouge, La.) Unit graphs and infiltration rates, Alabama (surface water) L. B. Peirce (5, Montgomery, Ala.) Flood-plain zoning D. G. Anderson (s, Charlottesville, Va.) Hydrologic and physical properties of soils and rocks D. A. Morris (g, D) Effects of grazing exclusion Colorado G. C. Lusby (h, D) Hydrologic efi'ect of small reservoirs, Honey Creek, Texas F. W. Kennon (h, Oklahoma City, Okla.) Mining hydrology W. T. Stuart (g, W) Hydrologic environmental studies J. N. Payne (g, Baton Rouge, La.) The geohydrologic environment as‘ related to water utili- zation in arid lands E. S. Davidson (g, Tucson, Ariz.) Lower Colorado River Basin hydrology C. C. McDonald (g, Yuma, Ariz.) Bank seepage during flood flows E. G. Pogge (s, Iowa City, Iowa) Tecolote Tunnel, California, effect on spring flow S. E. Rantz (s, M) Ground water-surface water interrelations, Kansas L. W. Furness (s, Topeka, Kans.) Analysis of surface water-ground water relationships in Hop Brook Basin, Massachusetts J. C. Kammerer (h, Boston, Mass.) Hydrology of lower Flett Creek basin, Washington F. M. Veatch (s, Tacoma, Wash.) Land-use evaluation F. W. Kennon (h, Oklahoma City, Okla.) Long term chronologies of hydrologic events (nation- wide) W. D. Simons (h, Tacoma, Wash.) Interpretation of data (surface water) G. C. Goddard (s, Raleigh, NC.) Time of travel of Ohio River water R. E. Steacy (s, Harrisburg, Pa.) Evaporation suppression: Effect of mechanical treatment on arid land in the West- ern United States F. A. Branson (h, D) in Badger Wash area, GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Evaporation suppression—Continued Evaporation suppression G. E. Koberg (h, D) Evaporation suppression studies (Throckmorton, Texas) G. E. Koberg (h, D) Field testing of evaporation suppression on small res- ervoirs G. E. Koberg (h, D) Artificial recharge of aquifers: Artificial recharge of aquifers R. T. Sniegocki (g, Little Rock, Ark.) Artificial recharge of basalt aquifers at the Dalles B. L. Foxworthy (g, Portland, Oreg.) Artificial recharge, Grand Prairie Region water) R. T. Sniegocki (g, Little Rock, Ark.) Experimental recharge basin, New York (surface water) R. M. Sawyer (s, Albany, N.Y.) Feasibility of artificial recharge of the Snake Plain aquifer, Idaho M. J. Mundorff (g, Boise, Idaho) Radioactive waste disposal investigations: Geochemical problems of radioactive waste disposal H. H. \Vaesche (W) Geology of the Appalachian Basin with reference to disposal of high-level radioactive wastes G. W. Colton (W) Geology of the Michigan Basin with reference to dis posal of high-level radioactive wastes W. deWitt (W) Geology of the Anadarko Basin, Oklahoma, with reference to disposal of high-level radioactive wastes M. MacLachlan (D) Geology of the Williston Basin with reference to the disposal of high-level radioactive wastes C. A. Sandberg (D) Geology of the Powder River basin, Wyoming, with reference to the disposal of high-level radio- active wastes H. Beikman (D) Rock salt deposits of the United States W. G. Pierce (M) Handbook on geology and hydrology in relation to the nuclear-energy industry (editor) R. L. Nace (w, W) Distribution and concentration of radioactive waste in streams by fluvial sediments D. W. Hubbell (q, D) Exchange phenomena and chemical reactions of ra- dioactive substances J. H. Baker (q, D) Geologic and hydrologic reconnaissance of potential reactor sites H. E. Gill (g, Trenton, NJ.) Geology and hydrology of the Central and North- eastern States as related to the management of radioactive materials W. C. Rasmussen (g, Newark, Del.) Geology and hydrology of Great Plains States as re- lated to the management of radioactive materials W. C. Rasmussen (g. Newark, Del.) (ground TOPICAL INVESTIGATIONS IN PROGRESS Radioactive waste disposal investigations—Continued Geology and hydrology of the western states as re— lated to the management of radioactive materials R. W. Maclay (g, St. Paul, Minn.) Research on hydrology, National Reactor Testing Sta- tion, Idaho E. H. Walker (g, Boise, Idaho) Hydrology of subsurface waste disposal, National Re actor Testing Station, Idaho P. H. Jones (g, Boise, Idaho} Geology, hydrology, and waste disposal at the Na- tional Reactor Testing Station, Idaho R. L. Nace (w, W) Distribution of elements as related to health: Airborne radioactivity and environmental studies, Wash- ington County, Maryland R. M. Moxham (W) Nevada Test Site (ground water) S. L. Schoff (g, D) Study of radioactive wastes P. H. Carrigan (s, Chattanooga, Tenn.) Stream sanitation and water supply G. C. Goddard (s, Raleigh, NC.) Behavior of detergents and other pollutants in soil- water environments C. H. Wayman (q, D) Mine drainage: *Geology in the vicinity of anthracite mine drainage projects, Pennsylvania T. M. Kehn (Mt. Carmel, Pa.) *Flood control, Anthracite region, Pennsylvania '1‘. M. Kehn (Mt. Carmel,‘Pa.) Geochemical and botanical exploration methods: Hydrogeochemical prospecting F. C. Canney (D) Botanical exploration and research H. L. Cannon (D) Geochemical halos of mineral deposits, California and Arizona L. C. Huff (D) Geochemical halos of mineral deposits, Utah and Nevada R. L. Erickson (D) Geochemical prospecting techniques, Alaska R. M. Chapman (D) Isotope geology in exploration: Studies of isotope geology of lead R. S. Cannon, Jr. (D) Radon and helium studies A. B. Tanner (W) Radioactive nuclides in minerals F. E. Senftle (W) Development of hydrologic techniques and instruments: Gaging flow through turbines B. J. Frederick (s, Chattanooga, Tenn.) Dispersion in natural streams R. G. Godfrey (s, W) Instrumentation research (water) E. G. Barron (s, Columbus, Ohio) Automation and processing techniques for water quality data G. A. Billingsley (q, Raleigh, NC) A—l55 Development of hydrologic techniques and instruments—Con. Development of a turbulence meter for field use R. E. Oltman (w, W) A study of methods used in measurement and analy- sis of sediment loads in streams B. C. Colby (q, Minneapolis, Minn.) Electronic equipment development J. E. Eddy (g, W) Analytical chemistry: Rock and mineral chemical analysis J. J. Fahey (W) General rock chemical analysis L. C. Peck (D) Research on trace analysis methods F. N. Ward (D) Trace analysis service and research F. N. Ward (D) Rapid rock chemical analysis W. W. Brannock (W) Analytical services and research I. May (W) Analytical services and research L. F. Rader, Jr. (D) Analytical services and research R. E. Stevens (M) A study of the occurrence and distribution of trace ele- ments in fresh and saline waters W. D. Silvey (q, Sacramento, Calif.) Analytical methods—water chemistry M. W. Skougstad (q, D) Spectroscopy : X-ray spectroscopy of ore minerals I. Adler (W) Spectrographic analytical services and research A. W. Helz (W) Spectrographic services and research A. T. Myers (D) Spectrographic services and research H. Bastron (M) Spectographic methods of analysis M. W. Skougstad (q, D) Mineralogic techniques: Mineralogy of fluvial sediments V. C. Kennedy (q, D) Photogeology : Photogeology research R. G. Ray (W) Photogeology training C. L. Pillmore (D) General bibliographies and handbooks: Bibliography of North American geology M. Cooper (W) Geophysical abstracts J. W. Clarke (W) Geochemical exploration abstracts and information E. L. Markward (D) Bibliography of tektites B. L. Smysor (W) Treatise on ground-water mechanics J. G. Ferris (g, W) A—156 GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS PUBLICATIONS IN EISCALXEAR 1961 Listed below are citations of technical reports of the Geologic, Water Resources, and Conservation Divisions published or otherwise released to the public during the fiscal year 1961. The list also includes a few recent publications dated prior to July 1, 1960, that were not listed in Professional Paper 400—A. It does not include articles in a few periodicals dated prior to July 1, 1961, but released after this date. The reports are listed alphabetically by author. In addition, an index to the reports is given on pages A—183 to A—194. LIST OF PUBLICATIONS Adler, Isidore, 1960a, Application of X-ray spectroscopy to un- solved problems in geochemistry, in Am. Soc. Testing Ma- terials, Symposium on spectroscopy: ASTM Spec. Tech. Pub. No. 269, p. 47—54. 1960b, Electron-probe identification and analysis of small mineral grains [abs.]: Geol. Soc. America Bull., v.~ 71, no. 12, pt. 2, p. 1812—1813. 19600, Nondestructive X-ray spectrographic analysis of extraterrestrial substances [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2089. Adolphson, D. G., 1960, Test drilling in the Walhalla area, Pem- bina County, North Dakota: US. Geol. Survey open-file re— port, 25 p., 4 figs. Albin, D. R., 1960, Geological explanation of Pinnacle Mountain: Little Rock, Arkansas, Gazette, June 26, 1960, p. 6E, 1 fig. Aldrich, L. T., and Brown, G. F., 1960, Distribution of ages ,in the Arabian segment of the African Shield [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1813. Allen, W. B., 1960, Ground-water conditions in the‘ Hunt River basin, Rhode Island—April 1960: U.S. Geol. Survey open- file report, 10 p. Allingham, J. W., and Bates, R. G., 1960, Geophysical investiga- tion in the Wausau area, Wisconsin [abs.]: Inst. Lake Superior Geology, 6th ann. mtg., Madison, Wis, April 1960, Program, p. 9. Anders, R. B., 1960, Ground-water geology of Karnes County, Texas: Texas Board Water Engineers Bull. 6007, 107 p., 19 figs. Andreasen, G. E., 1960a, Total intensity aeromagnetic profiles of the Yukon Flats-Kandik area, Alaska: U.S. Geol. Survey open-file report. 1960b, Total intensity aeromagnetic profiles for parts of the Kobuk, Minchumina, Cape Espenberg, Cape Lisburne, and Brooks Range areas, Alaska: US Geol. Survey open- file report. Andreasen, G. E., Grantz, Arthur, and Zietz, Isidore, 1960, Geologic interpretation of magnetic data in the Copper River Basin, Alaska: US. Geol. Survey open-file report, 37 p., 7 figs. Andreasen, G. E., Kane, M. F., and Zietz, Isidore, 1961, Aero- magnetic and gravity studies of the Precambrian in north- eastern New Mexico [abs.] : Soc. Explor. Geophysicists Yearbook 1961, p. 234. Appleman, D. E., 1960, The crystal structure of bikitaite, LiAlSigOa-Hzo [abs.]: Acta Cryst., v. 13, pt. 12, p. 1002. Archer, R. J ., 1960, Sediment discharges of Ohio streams during floods of January-February 1959: Ohio Dept. Nat. Re—i sources, Div. Water, Misc. Rept., 16 p., 2 p1s., 6 figs. Arnow, Ted, and Bogart, D. B., 1960, Water problems of Puerto Rico and a program of water-resources investigations: Car- ibbean Geol. Conf., 2d, Puerto Rico, 1959, Trans, p. 120—129. Arnow, Ted, and Crooks, J. W., 1960, Public water supplies in Puerto Rico: Puerto Rico Water Resources Bull. 2, 34 p., 2 figs. Ash, S. R., 1960, The Jicarilla Apache Indians of northern New Mexico, in Guidebook of the Rio Chama Country, New Mexico Geol. Soc. 11th Field Conf., 1960: p. 128—129. 1961a, Bibliography and index of conodonts, 1949—58: Micropaleontology, v. 7, no. 2, 32 p. 19611), Geology and ground-water resources of northern Lea County, New Mexico : U.S. Geol. Survey open-file report, 53 p., 20 figs. Ault, W. U., 1960, Geochemical research during the 1959—60 activity of Kilauea volcano: Geochem. News, no. 25, p. 1—5. Ault, W. U., Eaton, J. P., and Richter, D. H., 1961, Lava tem- peratures in the 1959 Kilauea eruption and cooling lake: Geol. Soc. America Bull., v. 72, no. 5, p. 791—794. Back, William, 1960a, Electrode for simplified field determination of chloride in ground water: Am. Water Works Assoc. J our., v. 52, no. 7, p. 923—926. 1960b, Hydrochemlcal facies and ground-water flow patterns in northern Atlantic Coastal Plain [abs.]: Am. Assoc. Petroleum Geologists Bull., v. 44, no. 7, p. 1244—1245. 1960c, Origin of hydrochemical facies of ground water in the Atlantic Coastal Plain: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 1, sec. 1, Proc., p. 87—95. —— 1961, Calcium carbonate saturation in ground water, from routine analyses: U.S. Geol. Survey Water-Supply Paper 1535—D, p. D-1—D-14. Bagnold, R. A., 1960, Some aspects of the shape of river meanders: U.S. Geol. Survey Prof. Paper 282—E, p. 135—144, figs. 81—87. Bailey, E. H., 1960, Franciscan formation of California as an example of eugeosynclinal deposition [abs.] : Geol. Soc. American Bull., v. 71, no. 12, pt. 2, p. 2046—2047. Bailey, E. B., and Stevens, R. E., 1960a, Selective staining of plagioclase and K-feldspar on rock slabs and thin sections [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2047. 1960b, Selective staining of K-feldspar and plagioclase on rock slabs and thin sections: Am. Mineralogist, v. 45, no. 9—10, p. 1020—1025. Baker, A. A., 1961a, Geologic map of the Aspen Grove quadrangle, Utah: US. Geol. Survey open-file report. 1961b, Geologic map of southeastern part of Brighton quadrangle, Utah: US. Geol. Survey open-file report. 1961c, Geologic map of southern part of Heber quad- rangle, Utah: US Geol. Survey open—file report. 1961d, Geologic map of the Orem quadrangle, Utah: US. Geol. Survey open-file report. 1961c, Geologic map of west half of Strawberry Valley quadrangle, Utah: US Geol. Survey open-file report. LIST OF PUBLICATIONS Baker, A. A., and Crittenden, M. D., Jr., 1961, Geology of the Timpanogos Cave quadrangle, Utah: U.S. Geol. Survey Geol. Quad. Map GQ-132. Baker, E. T.,- Jr., 1960, Geology and ground—water resources of Grayson County, Texas : Texas Board Water Engineers Bull. 6013, 152 p., 20 figs. Baker, J. A., 1960, Wetland and water supply: U.S. Geol. Survey Circ. 431, 3 p. Baker, R. C., 1961, Ground-water resources of the Lower Rio Grande Valley area, Texas: Texas Board Water Engineers Bull. 6014, v. 1, 81 p., 24 figs. ; v. 2, 336 p. Ball, J. S., Wenger, W. J., Hyden, H. J., Horr, C. A., and Myers, A. T., 1960, Metal content of twenty-four petroleums: Jour. Chem. Eng. Data, v. 5, no. 4, p. 553—557. Balsley, J. R., Hill, M. E., and Meuschke, J. L., 1961a, Total intensity aeromagnetic map of the McKeever quadrangle, New York: U.S. Geol. Survey open-file report. 1961b, Total intensity aeromagnetic map of the Old Forge quadrangle and part of the West Canada Lakes quadrangle, New York: U.S. Geol. Survey open-file report. Balsley, J. R., Rossman, D. L., and. Hill, M. E., 161a, Total intensity aeromagnetic map of the Big Moose quadrangle, New York: U.S. Geol. Survey open-file report. 1961b, Total intensity aeromagnetic map of parts of the Bolton, Whitehall, Glenn Falls, and Fort Ann quadrangles, New York : U.S. Geol. Survey open-file report. 1961c, Total intensity aeromagnetic map of the Eliza- bethtown, Paradox Lake, Port Henry, and Ticonderoga quadrangles, New York: U.S. Geol. Survey open-file report. 1961d, Total intensity aeromagnetic map of part of the Lowville quadrangle, New York: U.S. Geol. Survey open- file report. 1961c, Total intensity aeromagnetic map of the Number Four quadrangle, New York: U.S. Geol. Survey open-file report. 1961f, Total intensity aeromagnetic map of part of the Port Leyden quadrangle, New York: U.S. Geol. Survey open-file report. Baltz, E. H., and Ash, S. R., 1960, Road log from Gallina to vicinity of Cuba and alternate road log from Gallina to Upper San Jose drainage divide, in Guidebook of the Rio Chama Country, New Mexico Geol. Soc. 11th Field Conf., 1960: p. 40—44. Baltz, E. H.,‘Lamb, G. M., and Ash, ‘S. R., 1960, Road log from Lumberton to El Vado, in Guidebook of the Rio Chama Country, New Mexico Geol. Soc. 11th Field Conf., 1960: p. 27—32. Baltz, E. H., and Read, C. B., 1960, Rocks of Mississippian and probable Devonian age in Sangre de Cristo Mountains, New Mexico: Am. Assoc. Petroleum Geologists Bull., v. 44, no. 11, p. 1749—1774, 12 figs. Bannerman, H. M., 1960, Research and mineral resources: Canadian Mining J our., v. 81, no. 1, p. 45—49. Barnes, D. R, Allen, R. V., and Bennett, H. F., 1960, Gravity surveys in interior Alaska [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2085. Barnes, F. F., 1960, Coal-bearing strata of the Matanuska coal field, Alaska [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1820—1821. 1961, Coal fields of the United States, sheet‘ 2—Alaska: U.S. Geol. Survey. Barnes, H. H., Jr., and Bogart, D. B., 1961, Floods of Septem- ber 6, 1960, in eastern Puerto Rico: U.S. Geol. Survey Circ. 451, 13 p., 12 figs. A—157 Barnes, H. H., Jr., and Somers, W. P., 1961, Floods of February— March 1961 in the Southeastern States: U.S. Geol. Survey Circ. 452, 21 p., 12 figs. Barnett, P. R., 1961, An evaluation of whole-order, 1/2-order, and 1/3-order reporting in semiquantitative spectrochemical analysis: U.S. Geol. Survey Bull. 1084—H, p. 183—206, figs. 28—30. Barnett, R. H., and Moxham, R. M., 1961, Infrared phosphores- cence detection using pulsed excitation: Rev. Sci. Instru- ments, v. 32, no. 6, p. 740—741. Barron, E. G., 1960, New instruments of the Surface Water Branch, U.S. Geological Survey: Western Snow Cont, 28th, Santa Fe, New Mexico, 1960, Proc., p. 32—38, 3 figs. Barton, P. B., J r., Toulmin, Priestley, 3d, and. Sims, P. K., 1960, Role of chemical potential of sulfur in controlling mineral assemblages in sulfide deposits [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1821—1822. Bastron, Harry, Barnett, P. R., and Murata, K. J ., 1960, Method for the quantitative spectrochemical analysis of rocks, minerals, ores, and other materials by a powder d-c arc technique: U.S. Geol. Survey Bull. 1084—G, p. 165—182. Bath, G. D., and Schwartz, G. M., 1960, Magnetic anomalies and magnetization of main Mesabi iron-formation [abs] : Inst. Lake Superior Geology, 6th ann. mtg, Madison, Wis., April 1960, Program, p. 27. 1961, Total magnetization, an exploration parameter in the L‘ake Superior area [abs] : Soc. Explor. Geophysicists Yearbook 1961, p. 232. Bayley, R. W., 1960, The Precambrian taconite deposits near Atlantic City, Fremont County, Wyoming, in Overthrust belt of southwestern Wyoming and adjacent areas, Wyo- ming Geol. Assoc. Guidebook 15th Ann. Field Conf., 1960: p. 222—225. Bearden, G. A., Jr., 1960a, Water levels in artesian wells af- fected by moving railroad trains: U.S. Geol. Survey open- file report, 2 p., 1 fig. 1960b, Water levels in artesian wells afiected by moving railroad trains: Little Rock, Arkansas, Gazette, Dec. 25, 1960, p. 6D, 1 fig. Becraft, G. E., 1960a, Preliminary geologic map of the northern half of the Jefferson City quadrangle, Jefferson and Lewis and Clark Counties, Montana: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—171 [1961]. 1960b, Preliminary geologic map of the southern half of the Jefferson City quadrangle, Jefferson County, Mon- tana: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—172 [1961]. Becraft, G. E., and Pinckney, D. M., 1961, Preliminary geologic map of the northwest quarter of the Boulder quadrangle, Montana: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—183. Bell, Henry, III, and Overstreet, W. C., 1960, Geochemical and heavy-mineral reconnaissance of the Concord quarangle, Cabarrus County, North Carolina: U.S. Geol. Survey Min- eral Inv. Field Studies Map MF—234. Bell, K. G., 1960a, Deposition of uranium ‘in salt-pan basins: USS. Geol. Survey Prof. Paper 354—G, p. 161—169. 1960b, Uranium and other trace elements in petroleums and rock asphalts: U.S. Geol. Survey Prof. Paper 356—B, p. 45—66, fig. 22 [1961]. Bell, K. G., Rhoden, V. C., McDonald, R. L., and Bunker, C. M., 1961, Utilization of gamma-ray logs by the U.S. Geological Survey, 1949-53: U.S. Geol. Survey open-file report, 89 p., 24 figs, 1 table. A—158 Benda, W. K., Erd, R. C., and Smith, W. C., 1960, Core logs from five test holes near Kramer, California: U.S. Geol. Survey Bull. 1045—F, p. 319—393, pls. 11—12, fig. 8. Bennett, G. D., and Patten, E. P., J r., 1960, Borehole geophysical methods for analyzing specific capacity of multiaquifer wells: U.S. Geol. Survey Water-Supply Paper 1536—A, p. 1—25, figs. 1—8. Benson, M. A., 1960, Areal flood-frequency analysis in a humid region: Internat. Assoc. Sci. Hydrology, Bull. 19, p. 5—15. 1961, Peak discharge related to hydrologic characteristics in New England: Boston Soc. Civil Engineers Jour., v. 48, p. 48—67, 5figs. Bergendahl, M. H., Davis, R. E., and Izett, G. A., 1961, Geology and mineral deposits of the Carlile quadrangle, Crook County, Wyoming: U.S. Geol. Survey Bull. 1082—J, p. 613— 705, pls. 34—37, figs. 58-64. Berry, D. W., and Littleton, R. T., 1961, Geology and ground- water resources of the Owl Creek area, Hot Springs County, Wyoming: U.S. Geol. Survey Water-Supply Paper 1519, 58 p., 2 pls., 9 figs. Berryhill, H. L., J r., 1960, Geology of the Central Aguirre quad- rangle, Puerto Rico: U.S. Geol. Survey Misc. Geol. Inv. Map I—318 [1961]. Berryhill, H. L., Jr., and Glover, Lynn, 3d, 1960, Geology of the Cayey quadrangle, Puerto Rico: U.S. Geol. Survey Misc. Geol. Inv. Map I—319 [1961]. Bethke, P. M., Barton, P. B., Jr., and Bodine, M. W., Jr., 1960, Time-space relationships of the ores at Creede, Colorado [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1825— 1826. Blumenstock, D. I., Fosberg, F. B., and Johnson, C. G., 1961, The resurvey of typhoon effects on Jaluit Atoll in the Mar- shall Islands: Nature, v. 189, no. 4765, p. 618—620. Boardman, R. S., 1960, Trepostomatous Bryozoa of the Ham- ilton group of New York State: U.S. Geol. Survey Prof. Paper 340, 87 p., 22 pls. 27 figs. Bodhaine. G. L., 1960, Flood-frequency relationships in the Pacific Northwest: Am. Soc. Civil Engineers Proc., Hy- draulics Div. Jour., v. 86, no HY9, p. 1—10, 5 figs. Bogart, D. B., 1960, Floods of August—October 1955, New Eng- land to North Carolina: U.S. Geol. Survey Water-Supply Paper 1420, 854 p., 6 pls., 51 figs. Bogart, D. B., Arnow, Ted, and Crooks, J. W., 1960, Water problems of Puerto Rico and a program of water resources investigations: Puerto Rico Water Resources Bull. 1, 40 p., 3 figs. Boucot, A. J ., 1961, Stratigraphy of the Moose River synclino— rium, Maine: U.S. Geol. Survey Bull. 1111—E, p. 153—188, pl. 34, figs. 16—18. Bowen, B. M., Edgerton, J. H., Mohrbacker, J. A., and Callahan, J. T., 1960, Geological factors affecting the ground disposal of liquid radioactive wastes into crystalline rocks at the Georgia Nuclear Laboratory site: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 20, sec. 20, Proc., p. 32-48. Bowles, C. G., and Braddock, W. A., 1960, Solution breccias in the upper part of the Minnelusa sandstone, South Dakota and Wyoming [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2032. Brabb, E. E., and Miller, D. J ., 1960, Reconnaissance traverse across eastern Chugach Mountains, Alaska: U.S. Geol. Survey open-file report, 29 p., 1 pl. Bramkamp, R. A., and Ramirez, L. F., 1960a, Geographic map of the J awf-Sakakah quadrangle, Kingdom of Saudi Arabia : U.S. Geol. Survey Misc. Geol. Inv. Map I—201B [1961]. GEOLOGICAL SURVEY RESEARCH 1 9 6 l—SYNOPSIS OF RESULTS Bramkamp, R. A., and Ramirez, L. F., 1960b, Geographic map of the Darb Zubaydah quadrangle, Kingdom of Saudi Arabia: U.S. Geol. Survey Misc. Geol. Inv. Map I—202B. 1961, Geologic map of the Central Persian Gulf quad- rangle, Kingdom of Saudi Arabia: U.S. Geol. Survey Misc. Geol. Inv. Map I—209A. Bramkamp, R. A., Ramirez, L. F., and Brown, G. F., 1961, Geo- graphic map of the Wadi Ar Rimah quadrangle, Kingdom of Saudi Arabia: U.S. Geol. Survey Misc. Geol. Inv. Map I—206B. Breger, I. A., 1960. Diagenesis of metabolites and a discussion of the origin of petroleum hydrocarbons: Geochim, et Cosmochim. Acta, v. 19, no. 4, p. 297—308. 1961, Coalification of wood in uranium-bearing sandstone environments: Internat. Conf. Science of Coal, 4th, Letou- quet, France, June 1961, Preprint D—6, 15 p. Breger, I. A., and Chandler, J. C., 1960, Extractability of humic acid from coalified logs as a guide to temperatures in Colorado Plateau sediments: Econ. Geology, v. 55, no. 5, p. 1039—1047. Breger, I. A., Tourtelot, H. A., and Chandler, J. C., 1960, Geo- chemistry of kerogen from the Sharon Springs member of the Pierre shale [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1832—1833. Briggs, R. P., 1960, Laterization in east-central Puerto Rico: Caribbean Geol. Cont, 2d, Puerto Rico 1959, Trans, p. 103— 119 [1961]. 1961, Recent shoreline changes and sedimentation at Puerto Areci'bo and vicinity, Puerto Rico: Shore and Beach, v. 29, no. 1, p. 27—37. Brodsky, Harold, 1960, The Mesaverde group at Sunnyside, Utah: U.S. Geol. Survey open-file report, 70 p., 17 figs. Broedel, C. H., 1961, Preliminary geologic map showing iron and copper prospects in the Juncos quadrangle, Puerto Rico: U.S. Geol. Survey Misc. Geol. Inv. Map I—326. Brokaw, A. L., 1960, Geologic structure in the Mascot-Jefferson City, Tennessee, zinc district [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1834. Bromery, R. W., and Gilbert, F. P., 1961, Aeromagnetic maps of the Attean quadrangle and part of the Sandy Bay quad- rangle, Somerset County, Maine: U.S. Geol. Survey open- file report. Bromery, R. W., and Natof, N. C., 1961, Aeromagnetic maps of the Bingham quadrangle, Somerset County, Maine, and The Forks quadrangle, Piscataquis and Somerset Counties, Maine: U .S. Geol. Survey open-file report. Bromery, R. W., Zandle, G. L., and others, 1960a, Aeromagnetic map of the Collegeville quadrangle, Montgomery County, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—210. 1960b, Aeromagnetic map of part of the Bedminster quadrangle, Bucks County, Pennsylvania: U.S. Geol. Sur- vey Geophys. Inv. Map GP-260. 1960c, Aeromagnetic map of part of the Lumberville quadrangle, Bucks County, Pennsylvania, and Hunterdon County, New Jersey: U.S. Geol. Survey Geophys. Inv. Map GP—261. 1960d, Aeromagnetic map of the Telford quadrangle, Montgomery and Bucks Counties, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—262. 1960e, Aeromagnetic map of part of the Doylestown quadrangle, Bucks and Montgomery Counties, Pennsyl- vania: U.S. Geol. Survey Geophys. Inv. Map GP-263. LIST OF PUBLICATIONS Bromery, R. W., Zandler, G. L. and others. 1960f, Aeromagnetic map of the Lansdale quadrangle, Montgomery County, Pennsylvania : U.S. Geol. Survey Geophys. Inv. Map GP—264. 1960g, Aeromagnetic map of part of the Amber quad- rangle, Montgomery and Bucks Counties, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—265. 1961a, Aeromagnetic map of the Womelsdorf quadrangle, Berks, Lebanon, and Lancaster Counties, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—239. 1961b, Aeromagnetic map of the Sinking Spring quad- rangle, Berks and Lancaster Counties, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—240. 1961c, Aeromagnetic map of the Ephrata quadrangle, Lancaster County, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—241. I961d, Aeromagnetic map of the Terre Hill quadrangle, Lancaster and Berks Counties, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map. GP—242. 1961e, Aeromagnetic map of the Leola quadrangle, Lancaster County, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—243. 1961f, Aeromagnetic map of the New Holland quadrangle, Lancaster County, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—244. 1961g, Aeromagnetic map of the Gap quadrangle, Lancaster County, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—245. 1961b, Aeromagnetic map of the Lebanon quadrangle, Lebanon County, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—254. 1961i, Aeromagnetic map of the Richland quadrangle, Lebanon and Lancaster Counties, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—255. 1961j, Aeromagnetic map of the Manheim quadrangle, Lancaster and Lebanon Counties, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—256. 1961k, Aeromagnetic map of the Lititz quadrangle, Lancaster and Lebanon Counties, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—257. 19611, Aeromagnetic map of the Columbia East quad- rangle, Lancaster County, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—258. 1961m, Aeromagnetic map of the Lancaster quadrangle, Lancaster County, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP—259. Brosgé, W. P., Dutro, J. T., Jr., Mangus, M. D., and Reiser, H. N., 1960, Geologic map of the eastern Brooks Range, Alaska: U.S. Geol. Survey open-file report. Brosgé, W. P., and Reiser, H. N., 1960, Progress map of the geology of the Wiseman quadrangle, Alaska: U.S. Geol. Survey open-file report. Brosgé, W. P., Reiser, H. N., Patton, W. W., Jr., and Mangus, M. D., 1960, Geologic map of the Killik-Anaktuvuk Rivers region, Brooks Range, Alaska: U.S. Geol. Survey open-file report. Brown, C. E., and Whitlow, J. W., 1961, Geology of the Dubuque South quadrangle, Iowa-Illinois: U.S. Geol. Survey Bull. 1123—A, p. 1—93, pls. 1—7, figs. 1—18. Brown, G. F., 1960, Geomorphology of western and central Saudi Arabia: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 21, sec. 21, Proc., p. 150—159. Brown, G. F., and Jackson, R. 0., 1960, The Arabian Shield: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 9, sec. 9, Proc., p. 69—77. A—159 Brown, P. 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Carter, W. D., 1960, Origin of manto~type copper deposits of the Cabildo mining district, central Chile: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 16, sec. 16, Proc., p. 17—28. Castle, R. 0., 1960a, Geology of the Baldwin Hills area, Cali- fornia: U.S. Geol. Survey open-file report. 1960b, Surficial geology of the Beverly Hills and Venice quadrangles, California: U.S. Geol. Survey open-file report. Cater, F. W., and Elston, C. P., 1961, Structural development of salt anticlines of eastern Utah and western Colorado [abs]: Am. Assoc. Petroleum Geologists Bu11., v. 45, no. 3, p. 413. Cederstrom, D. J., 1961, Ground-water resources of the Fair- banks area, Alaska: U. S. Geol. Survey open-file report. Cederstrom, D. J ., and Tibbitts, G. 0., Jr., 1961, Jet drilling in the Fairbanks area, Alaska: U.S. Geol. Survey Water, Supply Paper 1539—B, p. B-1-B-28, 8 figs. Chao, E.C.T., 1960a, A device for viewing X-ray precession [photographs in three dimensions: Am. 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A., Jr., 1961, Preliminary geologic map of the Stewart Flat quadrangle, Caribou County, Idaho: U.S. Geol. Survey open-file report. Chisholm, W. A., Bergin, M. J., and Pritchard, G. E., 1961, Sedimentary petrology and sedimentation of the Miocene Browns Park formation [abs] : Am. Assoc. Petroleum Geologists, Rocky Mtn. Sec., and Soc. Econ. Paleontologists and Mineralogists, 46th ann. mtg, Denver, 0010., April 24— 27, 1961, Program, p. 84. Chodos, A. A., and Engel, C. G., 1961, Fluorescent X-ray spectro- graphic analyses of amphibolite rocks: Am. Mineralogist, v. 46, nos. 1—2, p. 120—133. Christ, C. L., and Clark, J. R., 1960a, Crystal chemical studies of some uranyl oxide hydrates : Am. Mineralogist, v. 45, nos. 9—10, p. 1026—1061. 1960b, The crystal structure of meyerhofferite, CaB303(OH)5-H20: Zeitschr. Kristallographie, v. 114, nos. 5/6, p. 321—342. Clark, J. R., 1960, X-ray crystallography of larderellite, NH4B503(OH).: Am. Mineralogist, v. 45, nos. 9—10, p. 1087—1093. Clark, J. 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S., and others, 1960a, Geophysical abstracts 180, J anuary-March 1960: U.S. Geol. Survey Bull. 1116—A, p. 1—128. 1960b, Geophysical abstracts 181, April—June 1960: U.S. Geol. Survey Bull. 1116—B, p. 129—279. 1960c, Geophysical abstracts 182, July—September 1960: U.S. Geol. Survey Bull. 1116—0, p. 281-455 [1961]. 1961a, Geophysical abstracts 183, October—December 1960: U.S. Geol. Survey Bull. 1116—D, p. 457—636. 1961b, Geophysical abstracts 184, January—March 1961: U.S. Geol. Survey Bull. 1146—A, 170 p. Clebsch, Alfred, Jr., 1960, Ground water in the Oak Spring formation and hydrologic efiects of nuclear explosions at the Nevada Test Site: U.S. Geol. Survey TEI—759, open-file report, 29 p., 5 figs. Clebsch, Alfred, J r., and Barker, F. B., 1960, Analyses of ground water from Rainier Mesa, Nevada Test Site, Nye County, Nevada: U.S. Geol. Survey TEI—763, open-file report, 22 p., 3 figs. Cline, D. R., 1960, A preliminary report of the geology and ground-water resources of upper Black Earth Creek basin, Wisconsin, with a section on Surface water, by Mark W. Busby: U.S. Geol. Survey open-file report, 45 p., 15 figs. LIST OF PUBLICATIONS Cloud, P. E., Jr., 1961, Paleobiogeography of the marine realm, in Mary Sears, ed., Oceanography: Am. Assoc. Adv. Sci. Pub. 67, p. 151—200, figs. 1-12. Coats, R. R., 1960, Method of minimizing damage to refractom- eters from the use of arsenic tribromide liquids: Am. Mineralogist, v. 45, nos. 7—8, p. 903—904. Cobban, W. A., and Gryc, George, 1961, Ammonites from the Seabee formation (Cretaceous) of northern Alaska: Jour. Paleontology, v. 35, no. 1, p. 176—190. Cohee, G. V., 1960, Geologic note: Am. Assoc. Petroleum Geologists Bull., v. 44, no. 9, p. 1578—1579. Colby, B. R., and Hubbell, D. W., 1961, Simplified methods for computing total sediment discharge with the modified Einstein procedure: U.S. Geol. Survey Water-Supply Paper 1593, 17 p., 8 pls. Cole, W. S., 1960, Upper Eocene and Oligocene larger Foraminif- era from Viti Levu, Fiji: U.S. Geol. Survey Prof. Paper 374—A, p. A-1—A-7, pls. 1—3, fig. 1 [1961]. Coleman, R. G., 1961, J adeite deposits of the Clear Creek area, New Idria district, San Venito County, California: Jour. Petrology, v.2, no. 2, p. 209—247. Colton, R. B., 1960, 'Surflcial geology of the Windsor Locks quadrangle, Connecticut: U.S. Geol. Survey Geol. Quad. Map GQ—137 [1961]. Conover, C. S., 1960, Ground-water resources—Development and management: U.S. Geol. Survey Circ. 442, 7 p. Cook, K. L., 1960, Gravity maps of the South Standard and Chief Oxide areas, East Tintic district, Utah: U.S. Geol. Survey open-file report. Cooper, J. B., 1960, Geologic section from Carlsbad Caverns National Park through the Project Gnome Site, Eddy and Lea Counties, New Mexico: U.S. Geol. Survey open-file report. Cordova, R. M., 1960, Arkansas had volcanoes long ago: Little Rock, Arkansas, Gazette, July 17, 1960, p. GE, 1 fig. Cornwall, H. R., and Kleinhampl, F. J., 1960a, Preliminary geologic map of the Bare Mountain quadrangle, Nye County, Nevada: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—239. 1960b, Structural features of the Beatty area, Nevada [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1845—1846. Cosner, 0. J., 1960, Ground water in the Wupatki and Sunset Crater National Monuments, Coconino County, Arizona: U.S. Geol. Survey open-file report. Cotter, R. D., and Rogers, J.E., 1961, Exploratory drilling for ground water in the Mountain Iron-Virginia area, St. Louis County, Minnesota: U.S. Geol. Survey Water-Supply Paper 1539—A, p. A—11—A—13, 2 pls., 2 figs. Cox, A. V., 1960a, Anomalous remanent magnetization of basalt : U.S. Geol. Survey Bull. 1083—E, p. 131—160, figs. 45—46 [1961]. 1960b, Variations in the direction of the dipole component of the earth’s magnetic field [abs]: Jour. Geophys. Re~ search, v. 65, no. 8, p. 2484. Cox, A. V., and Doell, R. R., 1961, Paleomagnetic evidence relevant to a change in the earth‘s radius: Nature, v. 189, no. 4758, p. 45—47. Craddock, Campbell, and Hubbard, H. A., 1961, Preliminary geologic report on the 1960 U.S. expedition to Bellingshausen Sea, Antarctica: Science, v. 133, no. 3456, p. 886—887. Crandell, D. R., 1961a, Surficial geology of the Orting quadrangle, Washington: U.S. Geol. Survey open-file report. 1961b, Surficial geology of the Sumner quadrangle, Wash— ington: U.S. Geol. Survey open-file report. A—161 Crandell, D. B., 19610, Surficial geology of the Wilkeson quad- rangle, Washington; U.S. Geol. Survey open-file report. Crandell, D. R., and Varnes, D. J ., 1960, Slumgullion earthfiow and earth slide near Lake City, Colorado [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1846. Creasey, S. 0., Jackson, E. D., and Gulbrandsen, R. A., 1961, Re— connaissance geologic map of parts of the San Pedro and Aravaipa Valleys, south-central Arizona: U.S. Geol. Sur- vey Mineral Inv. Field Studies Map MF—238. Cressman, E. R., and Swanson, R. W., 1960, Permian rocks in the Madison, Gravelly, and Centennial Ranges, Montana: Billings Geol. Soc. Guidebook, 11th Ann. Field Cont, West Yellowstone-Earthquake Area, Sept. 7—10, 1960: p. 226—232. Crittenden, M. D., 1960, Deformation of Bonneville shorelines [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1846. Cronin, J. G., 1960, Approximate saturated thickness of the Ogallala formation prior to large-scale development of ground water, Southern High Plains of Texas: U.S. Geol. Survey open-file report, 4 p., 1 map. Cronin, J. G., and Wells, L. G., 1960, Geology and ground-water resources of Hale County, Texas: Texas Board Water Engi- neers Bull. 6010, 146 p., 20 figs. Cross, W. P., 1961, Floods of J anuary-February 1959 in Ohio: Ohio Dept. Nat. Resources, Div. Water Bull. 35,176 p. Cruse, R. R., and Harbeck, G. E., Jr., 1960, Evaporation control research, 1955—58: U.S. Geol. Survey Water-Supply Paper 1480, 45 p., 1 pl., 14 figs. Cushing, E. M., 1960, The Mississippi Embayment study: South- west Water Works J our., v. 42, no. 7, p. 58, 60—61, 8 figs. Cuttitta, Frank, Meyrowitz, Robert, and Levin, Betsy, 1960, Dimethyl sulfoxide, a new diluent for methylene iodide heavy liquid: Am. Mineralogist, v. 45, nos. 5—6, p. 726—728. da Costa, J. A., 1960, Presentation of hydrologic data on maps in the United States of America: Internat. Assoc. Sci. Hydrology Pub. 32, p. 143—186, 35 figs. da Costa, J. A., and Bennett, R. R., 1960, The pattern of flow in the vicinity of a recharging and discharging pair of wells in an aquifer having areal parallel flow: Intemat. Assoc. Sci. Hydrology Pub. 52, p. 524—536, 9 figs. Dalrymple, Tate, 1960, Flood-frequency analysis, Manual of hydrology, part S—Flood-flow techniques: U.S. Geol. Sur- vey Water-Supply Paper 1543—A, p. 1-80, figs. 1—30. Dane, C. H., 1960a, The Dakota sandstone and Mancos shale of the eastern side of San Juan Basin, New Mexico, in Guide- book of the Rio Chama Country, New Mexico Geol. Soc. 11th Field Conf. 1960: p. 63—74. 1960b, Early explorations of Rio Arriba County, New Mexico, and adjacent parts of southern Colorado, in Guide- book of the Rio Chama Country, New Mexico Geol. Soc. 11th Field Conf. 1960: p. 113—127. Davies, W. E., 1960, Meteorological observations in Martens Cave, West Virginia: Natl. Speleol. Soc. Bull., v. 22, pt. 2, p. 92—100 [1961]. 1961, Antarctic research in geology: Natl. Acad. Sci.- Natl. Research Council Pub. 878, p. 98—104. Davies, ‘V. E., and Krinsley, D. B., 1960, Solution caves in northern Greenland: Natl. Speleol. Soc. Bull., v. 22, pt. 2, p. 114-116. Davis, G. 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J., 1960, Geology and ground-water resources of Hays County, Texas: Texas Board ‘Vater Engineers Bull. 6004, 167 p., 17 figs. de Witt, \Vallace, Jr., 1960, The Java formation of Late De vonian age in western and central New York: Am. Assoc. Petroleum Geologists Bull., v. 44, no. 12, p. 1933—1939. 1961, Geology of the Michigan basin with reference to subsurface disposal of radioactive wastes: U.S. Geol. Sur- vey TEI—7 71, open-file report, 100 p., 20 figs. Dibblee, T. W., J r., 1960a, Geologic map of the Barstow quad- rangle, San Bernardino County, California: U .S. Geol. Sur- vey Mineral Inv. Field Studies Map MF—233. 1960b, Geologic map of the Lancaster quadrangle, Los Angeles County, California: l'.S. Geol. Survey Mineral Inv. Field Studies Map MF—76 [1961]. 1961a, Geologic map of the Bouquet Reservoir quad- rangle. Los Angeles County, California: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—79. 1961b, Geology of the Rogers Lake and Kramer quad- rangles, California: U.S. Geol. Survey Bull. 1089—B, p. 73— 139, pls. 7—9, figs. 3, 4. Dickey, D. D., 1960, Thermoluminescence of some dolomite, tuff, and granitic rock samples from the north-central part of the Nevada Test Site, Nye County, Nevada—a progress report: U.S. Geol. Survey TEI—765, open-file report, 30 p., 7 figs, 6 tables. Diment, \V. H., Stewart, S. W., and Roller, J. C., 1960, Seismic observations of nuclear explosions at the Nevada Test Site at distances of 5 to 300 km [abs] : Union Géod. Géophys. Internal; Assoc. de Séismologie et de Physique de l’Inbérieur de la Terre, Assemblée d’Helsinki, Agenda et Resumes, Art. 11. 1961, Crustal structure from the Nevada Test Site to Kingman, Arizona, from seismic and gravity observations: Jour. Geophy. Research, v. 66, no. 1, p. 201—214. Dinnin, J. I., 19603, Notes on the preparation and construction of silver reductor columns: Anal. 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Survey open-file report, 243 p., 1 p1., 36 figs, 9 tables. Durfor, C. N., 1961, Water quality and hydrology in the Fort Belvoir area, Virginia, 1954—55: U.S. Geol. Survey Water- Supply Paper 1586—A, p. A-1—A—57,'20 figs. Durum, W. H., and Haffty, Joseph, 1961, Occurrence of minor elements in water: U.S. Geol. Survey Circ. 445, 11 p., 4 figs. Dutcher, L. C., 1960, Ground-water inventory for 1958, Edwards Air Force Base, California: U.S. Geol. Survey open-file report, 69 p., 10 pls. Dutcher, L. C., and Hiltzen, W. J ., 1960, Appendix A, Tables of basic data for wells on Edwards Air Force Base; Appendix B, Tables of basic data for areas outside Edwards Air Force Base: U.S. Geol. Survey open—file report, 199 p., 2 pls. Dutcher, L. C., and Worts, G. F., Jr., 1960, Geology and ground- water appraisal of Edwards Air Force Base and vicinity, California: U.S. Geol. Survey open-file report, 229 p., 13 pls., 1 fig. Dutton, C. 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Survey Prof. Paper 354—B, p. 11—49, figs. 6—13. 1960b, Interpreation of the composition of lithium micas: U.S. Geol. Survey Prof. Paper 354—E, p. 115—147, figs. 25—39. 1960c, Fe203 in chlorites [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1867. Foster, M. D., Bryant, Bruce, and Hathaway, J. C., 1960, Iron- rich muscovitic mica from the Grandfather Mountain area, North Carolina: Am. Mineralogist, v. 45, 0s. 7—8, p. 839— 851. Fournier, R. 0., 1960, Solubility of quartz in ater in the tem- perature interval from 25°C. to 300°C. [ bs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1867—18 Fowler, K. H., 1960, Preliminary report on gr Salmon Falls area, Twin Falls County, Survey Circ. 436, 17 p., 1 pl., 4 figs. [1961]. Fraser, G. D., 1960, Geologic interpretation of he Hebgen Lake earthquake, Montana [abs]: Geol. Soc. merica Bull., v. 71, no. 12, pt. 2, p. 2034. Freeman, V. L., 1961, Contact of Boquillas flags and Austin chalk in Val Verde and Terrell Counties, Petroleum Geologists Bull., v. 45, no. 1, p. 105—107. nd water in the aho: U.S. Geol. A—164 Friedman, Irving, Schoen, Beatrice, and Harris, Joseph, 1961, The deuterium concentration in Arctic sea ice: J our. Geophys. Reseach, v. 66, no. 6, p. 1861—1864. Friedman, Irving, and Smith, R. L., 1960, A new dating method using obsidian: Part 1—The deve10pment of the method: Am. Antiquity, v. 25, no. 4, p. 476—522. Friedman. Irving, Thorpe, Arthur, and Senftle, F. E., 1960a, Comparison of the chemical composition and magnetic properties of tektites and glasses formed by fusion of ter- restrial rocks: Nature, v. 187, no. 4743, p. 1089—1092. 1960b, Tektites and glasses from melted terrestrial rocks [abs] : Jour. Geophys. Research, v. 65, no. 8, p. 2491. Friedman, S. A., 1961, Geology and coal deposits of the Terre Haute and Dennison quadrangles. Vigo County, Indiana: U.S. Geol. Survey Coal Inv. Map C—44. Fries, Carl, Jr., 1960, Geologia del estado de Morelos y de partes adyacentes de Mexico y Guerrero, region central meridional de Mexico: [Mexico] Inst. Geologia B01. 60, 236 p. Frischknecht, F. C., and Mangan, G. B., 1960, Preliminary report on electromagnetic model studies: U.S. Geol. Survey open-file report, 12 p., 80 figs. Froelich, A. J., and Kleinhampl, F. J., 1960, Botanical pros- pecting for uranium in the Deer Flat area, White Canyon district, San Juan County, Utah: U.S. Geol. Survey Bull. 1085—B, p. 51—84, pl. 6, figs. 2—3. Fryklund, V. C., J r., 1961, General features of the ore deposits of the Coeur d’Alene district, Idaho, in Guidebook to the geology of the Coeur d’Alene mining district: Idaho Bur. Mines and Geology Bull. 16, p. 6—8. Furness, L. W., 1960, Kansas streamflow characteristics, pt. 2——LOW-flow frequency: Kansas Water Resources Board Tech. Rept. no. 2, 179 p. Gardner, L. S., 1961, Preliminary geologic map, columnar sec- tions and trench sections of the Irwin quadrangle. Caribou and Bonneville Counties, Idaho, and Lincoln and Teton Counties, Wyoming: U.S. Geol. Survey open-file report. Gates, G. 0., and Gryc, George, 1961, Structure and tectonic history of Alaska [abs.] : Am. Assoc. Petroleum Geologists Bull., v. 45, no. 3, p. 418. Gates, J. S., 1961, Geohydrology of Middle Canyon, Oquirrh Mountains, Tooele County, Utah: Utah Water and Power Board 7th Bienn. Rept., p. 55—72, 4 figs. Geurin, J. W., 1960, Research and basic data in water quality: U .S. Geol. Survey open-file report, 6 p. Gibbons, A. B., Hinrichs, E. N., Dickey, D. D., McKeown, F. A., Poole, F. G., and Houser, F. N., 1961, Engineering geology of test sites in granite and dolomite at Gold Meadows, Climax, and Dolomite Hill, Nevada Test Site, Nye County, Nevada—preliminary report: U.S. Geol. Survey TEM—884, open-file report, 42 p., 5 figs, 6 tables. Gill, H. E., 1960, Evaporation losses from small-orifice rain gages: Jour. Geophys. Research, v. 65, no. 9, p. 2877—2881, 4 figs. Gill, J. R., Schultz, L. G., and Tourtelot, H. A., 1960, Correla- tion of units in the lower part of the Pierre shale, Great Plains region [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2034. Giroux, P. R., and Thompson, Ted, 1961, Summary of ground- water conditions in Michigan, 1959: Michigan Geol. Survey Water-Supply Rept. 4, 69 p., 21 figs. Goldsmith, Richard, 1960a, A post-Harbor Hill-Charlestown moraine in southeastern Connecticut: Am. J our. Sci., v. 258. no. 10, p. 740—743. GEOLOGICAL SURVEY RESEARCH l96l—SYNOPSIS OF RESULTS Goldsmith, Richard, 1960b, Surficial geology of the Uncasville quadrangle, Connecticut: U.S. Geol. Survey Geol. Quad. Map GQ-138 [1961]. Goode, H. D., and Eardley, A. J., 1960, Lake Bonneville: a pre- liminary report on the Quaternary deposits of Little Val- ley, Promontory Range, Utah [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2035. Gordon, E. D., King, N. J., Haynes, G. L., Jr., and Cummings, T. R., 1960, Occurrence and quality of water in the northern Bridger basin and the adjacent overthrust belt, Wyoming, in Overthrust belt of southwestern Wyoming and adjacent areas, Wyoming Geol. Assoc. Guidebook 15th Ann. Field 1960: Cont. p. 227—247. Gott, G. B.. Braddock, W. A., and Post, E. V., 1960, Uranium deposits of the southwestern Black Hills [abs.] : Geol. Soc. America Bull., v. 71. no. 12, pt. 2, p. 2035. Gower, H. D., 1960, Geology of the Pysht quadrangle, Wash- ington: U.S. Geol. Survey Geol. Quad. Map ‘GQ—129. Gower, H. D., Vine, J. D., and Snavely, P. D., Jr., 1960, Deposi- tional environment of the Eocene coal deposits of Wash- ington [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1873. Grantz, Arthur, Zietz, Isidore, and Andreasen, G. E., 1960, An aeromagnetic reconnaissance of the Cook Inlet area, Alaska: U.S. Geol. Survey open-file report, 66 p., 9 figs. Green, A. R., and Hoggatt, R. E., 1960, Floods in Indiana, mag- nitude and frequency: U.S. Geol. Survey open-file report, 145 p., 10 figs. Griscom, Andrew, 1960a, The bulk composition of a zoned crys- tal: Am. Mineralogist, v. 45, nos. 11—12, p. 1309—1312. 1960b, Geology of the Stratton quadrangle, Maine, Trip A, in New England Intercollegiate Geol. Conf. Guidebook, 52d ann. mtg, Rumford, Maine, 1960 : p. 3—8. 1960c, Geophysical studies in the Maryland Piedmont [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1875. Griscom. Andrew, and Milton, D. J ., 1960, Introduction, in New England Intercollegiate Geol. Conf. Guidebook, 52d ann. mtg., Rumford, Maine, 1960: p. 1—2. Grogin, M. J., 1960, County quality of water maps for New Mexico—Roosevelt and Curry Counties: U.S. Geol. Survey open-file report. Groot, C. R., 1960, Feasibility of artificial recharge at Newark, Delaware: Am. Water Works Assoc. J0ur., v. 52, no. 6, p. 749—755. Griinenfelder, Marc, and Stern, T. W., 1960, Das Zirkon-Alter des Bergeller Massivs: Schweizerische Mineralog. 11nd Petrog. Mitt., v. 40, no. 2, p. 253—259. Gude, A. J., 3d. Young, E. J., Kennedy, V. C., and Riley, L. B., 1960, Whewellite and celestite from a fault opening in San Juan County, Utah: Am. Mineralogist, v. 45, nos. 11—12, p. 1257—1265. Gulbrandsen, R. A., 1960a, Minor elements in phosphorites of the Phosphoria formation [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1876. 1960b, Petrology of the Meade Peak phosphatic shale member of the Phosphoria formation at Coal Canyon, Wyo- ming: U.S. Geol. Survey Bull. 1111—C, p. 71—146, pls. 28-33, figs. 4—14 [1961]. 1960c, A method of X-ray analysis for determining the ratio of calcite to dolomite in mineral mixtures: U.S. Geol. Survey Bull. 1111—D, p. 147—152, fig. 15 [1961]. Gulbrandsen, R. A., and Cressman, E. R., 1960, Analcime and albite in altered Jurassic tuff in Idaho and Wyoming: Jour. Geology, v. 68, no. 4, p. 458—464. LIST OF PUBLICATIONS Hack, J. T., 1960, Origin of talus and scree in northern Virginia [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1877— 1878. Hack, J. T., and Goodlett, J. (J., 1960, Geomorphology and forest ecology of a mountain region in the central Appalachians: U.S. Geol. Survey Prof. Paper 347, 66 p., 6 pls., 31 figs. [1961]. Hackett, O. M., Visher, F. N., McMurtrey, R. G., and Steinhilber, W. L., 1960, Geology and ground-water resources of the Gallatin Valley, Gallatin County, Montana, with a section on Surface-water resources by Frank Stermitz and F. C. Boner, and a section on Chemical quality of the water, by R. A. Krieger: U.S. Geol. Survey Water-Supply Paper 1482, 282 p., 11 pls., 40 figs. Hackman, R. J ., 1961a, Geology of the moon: Space Sci., v. 10, no. 10, p. 1—6. 1961b, Photointerpretation of the lunar surface: Photo- gramm. Eng., v. 27, no. 3, p. 377—386. Hadley, J. B., 1960a, The Madison landslide, in Billings Geol. Soc. Guidebook 11th Ann. Field Conf., West Yellowstone- Earthquake Area, Sept. 7—10,.1960: p. 45—48. 1960b, Geology of the northern part of the Gravelly Range, Madison County, Montana, in Billings Geol. Soc. Guidebook 11th Ann. Field Conf., West Yellowstone-Earth— quake Area, Sept. 7—10, 1960: p. 149—153. Hadley, R. F., 1960, Recent sedimentation and erosional history of Fivemile Creek, Fremont County, Wyoming: U.S. Geol. Survey Prof. Paper 352—A, p. 1-16, pls. 1—4, figs. 1—7. Haffty, Joseph, 1960, Residue method for common minor ele- ments: U.S. Geol. Survey Water-Supply Paper 1540—A, p. 1—9. fig. 1. Hale, M. D., and Hoggatt, R. E., 1961, Floods of J anuary—Feb- ruary 1959 [in Indiana] : U.S. Geol. Survey Circ. 440, 23 p., 17 figs. Haley, B. R., 1960, Coal resources of Arkansas, 1954: U.S. Geol. Survey Bull. 1072—P, p. 795—831, pls. 58—64, figs. 43—45. Hall, F. R., and Palmquist, W. N., Jr., 1960a, Availability of ground water in Bath, Fleming, and. Montgomery Counties, Kentucky: U.S. Geol. Survey Hydrol. Inv. Atlas HA—18. 1960b, Availability of ground water in Clark, Estill, Mad- ison, and Powell Counties, Kentucky: U.S. Geol. Survey Hydrol. Inv. Atlas HA—19. 1960c, Availability of ground water in Marion, Nelson, and Washington Counties, Kentucky: U.S. Geol. Survey Hydrol. Inv. Atlas HA——21. 1960d, Availability of ground water in Carroll, Gallatin, Henry, Owen, and Trimble Counties, Kentucky: U.S. Geol. Survey Hydrol. Inv. Atlas HA—23. 1960c, Availability of ground water in Anderson, Frank- lin, Shelby, Spencer, and Woodford Counties, Kentucky: U. S. Geol. Survey Hydrol. Inv. Atlas HA—24. Hamilton, Warren, 1960a, Form of the Sudbury lopolith: Cana- dian Mineralogist, v. 6, p. 437—447. 1960b, Late Cenozoic tectonics and volcanism of the Yellowstone region, Wyoming, Montana, and Idaho, in Bill- ings Geol. Soc. Guidebook 11th Ann. Field Cont, West Yel- lowstone-Earthquake Area, Sept. 7—10, 1960: p. 92—105. 19600, Late Cenozoic tectonics and volcanism of the Yel— lowstone region, Wyoming, Idaho, and Montana [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1879. 608400 0—61—12 A—165 Hamilton, Warren, 1960d, Motion pictures of geologic field work in the Antarctic [abs] : Jour. Geophys. Research, v. 65, no. 8, p. 2495. 1960e, Origin of the Gulf of California [abs]: Jour. Geophys. Research, v. 65, no. 8, p. 2495. 1960f, Silicic differentiates of lopoliths: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 13, sec. 13, Proc., p. 418— 434. 1961, Tectonics of Antarctica [abs]: Am. Assoc. Petro- leum Geologists Bull., v. 45, no. 3, p. 408. Hansen, W. R., 1960, Precambrian rocks of the eastern Uinta Mountains—a classic relationship [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1880—1881. 1961a, Geologic map of the Dutch John Mountain and Goslin Mountain quadrangles, Utah-Wyoming: U.S. Geol. Survey Misc. Geol. Inv. Map 1—324. 1961b, Geologic map of the Willow Creek Butte quad- rangle, Utah-Colorado: U.S. Geol. Survey Misc. Geol. Inv. Map I—322. Harbeck, G. E., Jr., 1960, Suppressing evaporation from water surfaces: Am. Assoc. Adv. Sci., Water and Agr. Pub. 62, p. 171—172. Harbeck, G. E., Jr., Golden, H. G., and Harvey, E. J., 1961, Effect of irrigation withdrawals on stage of Lake Wash- ington, Mississippi: U.S. Geol. Survey Water-Supply Paper 1460—1, p. 359—388, figs. 33-49. Harbour, R. L., 1960, Precambrian rocks at North Franklin Mountain, Texas: Am. Assoc. Petroleum Geologists Bull., v. 44, no. 11, p. 1785—1792. Harder, A. H., 1960a, The geology and groundwater resources of Calcasieu Parish, Louisiana: U.S. Geol. Survey Water— Supply Paper 1488, 102 p., 9 pls., 29 figs. 1960b, Water levels and water-level contour maps for southwestern Louisiana, 1958 and 1959: Louisiana Dept. Conserv., Dept. Public Works, Water Resources Pamph. 8, 27 p., 3 pls., 7 figs. Hardt, W. F., Stulik, R. S., and Booher, M. B., 1960, Annual report on ground water in Arizona, spring 1959 to spring 1960: Arizona State Land Dept. Water Resources Rept. 7, 72 p., 22 figs. Harrison, J. E., and Moench, R. H., 1961, Joints in Precambrian rocks, Central City-Idaho Springs area, Colorado: U.S. Geol. Survey Prof. Paper 374—B, p. B—1—B-14, figs. 1—13. Hart, D. L., Jr., 1961a, Fluctuations of water levels in wells: Oklahoma Geol. Notes, v. 21, no. 2, p. 41—47, 8 figs. 1961b, Ground water in the alluvium of Beaver Creek basin, Oklahoma: U.S. Geol. Survey open-file report, 13 p., 1 fig. Hartshorn, J. H., 1960, Geology of the Bridgewater quadrangle, Massachusetts: U.S. Geol. Survey Geol. Quad. Map GQ—127. Harvey, E. J., and Nichols, J. L., 1960, Stratigraphy of the Quaternary and Upper Tertiary of the Pascagoula Valley, Mississippi, in Gulf Coast Assoc. Geol. Soc. Guidebook 10th ann. mtg, Biloxi, Mississippi, Oct. 1960: p. 9—22, 3 pls., 7 figs. Hathaway, J‘. 0., and Robertson, E. C., 1960, Microtexture of artificially consolidated aragonitic mud [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1883. Hawley, C. C., 1960, Origin of asphaltite-rich ore bodies at Temple Mountain, Emery County, Utah [abs]: Geol. Soc. America Bull., v. 71. no. 12, pt. 2, p. 1884. Heindl, L. A., and Cosner, O. J., 1960, Hydrologic data and drillers’ logs, Papago Indian Reservation, Arizona: U.S. Geol. Survey open-file report, 23 p., 3 figs. A—166 Hem, J. D., 1960, Chemical equilibrium diagrams for ground- water systems: Internat. Assoc. Sci. Hydrology Bull. 19, p. 52, 3 figs. 1961a, Calculation and use of ion activity: U.S. Geol. Survey Water-Supply Paper 1535—0, p. C-1—Cl7, 1 p1., 2 figs. 1961b, Stability field diagrams as aids in iron chemistry studies: Am. Water Works Assoc. Jour., v. 53, no. 2, p. 211- 228, 6 figs. Hembree, C. H., and Rainwater, F. H., 1961, Chemical degrada- tion on opposite flanks of the Wind River Range, Wyoming: U.S. Geol. Survey Water-Supply Paper 1535—E, p. E-l—E-9, 3 figs. Hendricks, E. L., Kam, William, and Bowie, J. E., 1960, Prog- ress report on use of water by riparian vegetation, Cotton- wood Wash, Arizona: U.S. Geol. Survey Circ. 434, 11 p., 3 figs. Hendrickson, G. E., and Kreiger, R. A., 1960, Relationship of chemical quality of water to stream discharge in Ken- tucky: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 1, sec. 1, Proc., p. 66—75. Henry, H. R., 1960, Salt intrusion into coastal aquifers: U.S. Geol. Survey open-file report, 42 p., 14 figs. Herrick, E. H., 1960a, Ground-water resources of the head- quarters (cantonment) area, White Sands Proving Ground, Dona Ana County, New Mexico: U.S. Geol. Survey open-file report, 203 p., 1 pl., 32 figs. 1960b, Reconnaissance of ground-water conditions south- east of Valmont, Otero County, New Mexico; U.S. Geol. Survey open-file report, 5 p., 1 fig. 1960c, Rehabilitation of wells in the headquarters area, White Sands Proving Ground, Dona Ana County, New Mexico: U.S. Geol. Survey open-file report, 27 p., 7 figs. 1961, Conservation of floodwater at White Sands Missile Range, Dona Ana County, New Mexico: U.S. Geol. Survey Hydrol. Inv. Atlas HA—42. Herrick, S. M., 1960, Late Eocene Foraminifera from South Carolina and Georgia [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2016—2017. Herz, Norman, and Dutra, C. V., 1960, Minor element abundance in a part of the Brazilian shield: Geochim. et Cosmochim. Acta, v. 21, nos. 1/2, p. 81—98. Hewett, D. F., Chesterman, C. W., and Troxel, B. W., 1961, Tephroite in California manganese deposits: Econ. Geology, v. 56, no. 1, p. 39—58. Hill, D. P., and Jacobson, J. J., 1961, Gravity survey in the western. Snake River Plain, Idaho—a progress report: U.S. Geol. Survey open-file report, 20 p., 4 figs, 2 pls. Hite, R. J ., 1960, Stratigraphy of the saline facies of the Para- dox member of the Hermosa formation of southeastern Utah and southwestern Colorado, in Geology of the Para- dox basin fold and fault belt, Four Corners Geol. Soc. Guidebook 3d Field Conf., 1960, p. 86—89. Hoare, J. M., 1961, Geology and tectonic setting of Lower Kus- kokwim-Bristol Bay region, Alaska: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 5, p. 594—611. Hoare, J. M., and Coonrad, W. L., 1961, Geologic map of the Hagemeister Island quadrangle, Alaska: U.S. Geol. Sur- vey Misc. Geol. Inv. Map I—321. Hodson, W. G.. and Wahl, K. D., 1960, Geology and ground-water resources of Gove County, Kansas: Kansas Geol. Survey Bull. 145, 126 p., 6 p1., 18 figs. GEOLOGICAL SURVEY RESEARCH l96l—SYNOPSIS OF RESULTS Hoffman, J. F., and Lubke, E. R., 1961, Ground-water levels and their relationship to ground-water problems in Suffolk County, Long Island, New York: New York Water Re- sources Comm., Bull. GWA4, 42 p., 2 pls., 6 figs. Holzle, A. F., 1960, Photogeologic map of the Cabezon—3 quad- rangle, McKinley and Sandoval Counties, New Mexico: U.S. Geol. Survey Misc. Geol. Inv. Map I—317. Hood, J. W., 1960a, Availability of ground water in the vicinity of Cloudcroft, Otero County, New Mexico: U.S. Geol. Sur- vey open-file report, 26 p., 1 fig. 1960b, Ground water in the vicinity of the Atlas site, Holloman Air Force Base, Otero County, New Mexico: U.S. Geol. Survey open-file report, 38 p., 1 p1., 4 figs. Hood, J. W., Mower, R. W., and Grogin, M. J., 1960, The oc- currence of saline ground water near Roswell, Chaves County, New Mexico: New Mexico State Engineer Tech. Rept. 17, 93 p., 12 pls., 14 figs. Hopkins, D. M., MacNeil, Steams, and Leopold, E. B., 1960, The coastal plain at Nome, Alaska—a late Cenozoic type sec— tion for the Bering Strait region: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 4, sec. 4, Proc., p. 46—57. Hopkins, D. M., and \Vahrhaftig, Clyde, 1960, Annotated bibli- ography of English language papers on the evolution of slopes under periglacial climates: Zeitschr. Geomorphologie, supp. v. 1, p. 1—8. Hopkins, W. B., and Simpson, T. A., 1960, Montana earthquakes noted in Pennsylvania mine—water pools: Am. Geophys. Union Trans, v. 41, no. 3, p. 435—436. Horr, C. A., Myers, A. T., and Danton, P. J., 1961, Methods of analysis for uranium and other metals in crude oils, with data on reliability: U.S. Geol. Survey Bull. 1100—A, p. 1—15. Hose, R. K., Repenning, C. A., and Ziony, J. I., 1960, Generalized geologic map of a part of the Confusion Range, Utah: U.S. Geol. Survey open-file report. Hosman, R. L., 1960a, Arkansas A coastal state? A geologic history of the Mississippi Em’bayment: U.S. Geol. Survey open-file report, 6 p., 1 fig. 1960b, Arky’s aquafacts: U.S. Geol. Survey open-file re— port, 5 figs. 1960c, Electric log important to geologists: Little Rock, Arkansas, Gazette, July 10, 1960, p. GE, 2 figs. 1961, The embayment: Little Rock, Arkansas, Gazette, Jan. 8, 1961, p. 2E, 1 fig. Hosterman, J. W., 1960, Geology of the clay deposits in parts of Washington and Idaho: Natl. Conf. Clays and Clay Minerals, 7th, Washington, D.C., 1958, Proc., p. 285—292. Hosterman, J. W., Scheid, V. E., Allen, V. T., and Sohn, I. G., 1961, Investigations of some clay deposits in Washington and Idaho: U.S. Geol. Survey Bull. 1091, 147 p., 9 pls., 4 figs. Hotz, P. E., and \Villden, Ronald, 1960, Preliminary geologic map and sections of the Osgood Mountains quadrangle, Humboldt County, Nevada: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—161 [1961]. Houser, F. N., and Poole, F. G., 1960a, Preliminary geologic map of the Climax stock and vicinity, Nye County, Nevada: U.S. Geol. Survey Misc. Geol. Inv. Map 1—328. 1960b, Primary structures in pyroclastic rocks of the Oak Spring formation (Tertiary), northeastern Nevada TeSt Site, Nye County, Nevada [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2062—2063. LIST OF PUBLICATIONS Howard, A. D., 1960, Cenozoic history of northeastern Montana and northwestern North Dakota, with emphasis on the Pleistocene: U.S. Geo]. Survey Prof. Paper 326, 107 p., 8 pls., 44 figs. [1961]. Hubbell, D. W., 1960, Progress report 2, Investigations of some sedimentation characteristics of sand-bed streams: U.S. Geo]. Survey open-file report, 54 p., 15 figs, 8 tables. Hubble, J. H., and Collier, C. R., 1960, Quality of surface water in Ohio, 1946—1958: Ohio Dept. Nat. Resources, Div. Water, Ohio Water Plan Inventory, Rept. 14, 317 p., 4 pls., 2 figs. Huff, L. C., Lovering, T. G., Lakin, H. W., and Myers, A. T., 1960, Comparison of analytical methods used in geochemical prospecting for copper [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1893. Hughes L. S., and Jones, Wanda, 1961, Chemical composition of Texas surface waters, 1958: Texas Board Water Engi- neers Bull. 6104, 82 p., 1 pl., 3 figs. Hummel, C. L., 1960, Structural geology and structural control of mineral deposits in an area near Nome, Alaska [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2063. Hunt, C. B., 1960a, Geological evidence of age of early man sites near Moab, Utah: Am. Antiquity, v. 26, no. 1, p. 115—116. 1960b, Petrography of the pottery, in Hunt, A. P., Arche ology of the Death Valley salt pan: Utah Univ. Anthropol. Papers, no. 47, p. 195—201. 1961, Tectonic framework of southwestern United States, and possible continental rifting [abs.]: Am. Assoc. Petro- leum Geologists Bull., v. 45, no. 3, p. 412. Hutchison, H. 0.,‘1960, Geology and coal deposits of the Brazil quadrangles, Indiana: Indiana Geo]. Survey Bull. 16, 50 p., 2 pls., 3 figs. Hyden, H. J., 1961, Distribution of uranium and other metals in crude oils: U.S. Geo]. Survey Bull. 11MB, p. 17—99, pls. 1—3, figs. 1—39. Imlay, R. W., 1960a, Ammonites of Early Cretaceous age (Valanginian and Hauterivian) from the Pacific Coast States: U.S. Geo]. Survey Prof. Paper 334—F, p. 167—228, pls. 24—43, figs. 34—36. Chitina Valley and Talkeetna Mountains, Alaska : U.S. Geo]. Survey Prof. Paper 354—D, p. 87—114, pls. 11—19, figs. 21—24. 1961, New genera and subgenera of Jurassic (Bajocian) ammonites from Alaska: Jour. Paleontology, v. 35, no. 3, p. 467—474. Irwin, W. P., 1960, Geologic reconnaissance of the northern Coast Ranges and Klamath Mountains, California: Cali- fornia Div. Mines Bull. 179, 80 p., 16 pls., 16 figs. Izett, G. A., 1960, “Granite” exploration hole, Area 15, Nevada Test Site, Nye County, Nevada, Interim report, Part 0— Physical properties: U.S. Geo]. Survey TEM—836—C, open- file report, 36 p., 3 figs, 10 tables. Izett, G. A., Mapel, W. J., and Pillmore, C. L., 1960, Early Cretaceous folding on the west flank of the Black Hills, Wyoming [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2036. Jackson, E. D., 1961, Primary textures and mineral associations in the ultramafic zone of the Stillwater complex, Montana: U.S. Geo]. Survey Prof. Paper 358, 106 p., 92 figs. Jackson, E. D. Dinnin, J. I., and Bastron, Harry, 1960, Strati- graphic variation of chromite composition within chromitite zones of the Stillwater complex, Montana [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2. p. 1896. 1960b, Early Cretaceous (Albian) ammonites from the A—167 Jahren, C. E., 1960, Magnetizations of iron-formations and ig- neous rocks of northern Minnesota [abs.] : Inst. Lake Supe- rior Geology, 6th ann; mtg, Madison, Wis, April 1960, Program, p. 28. Jenkins, C. T., 1960a, Floods in Tennessee, magnitude and fre- quency: Tennessee Dept. Highways Rept., 65 p., 1 pl., 7 figs. 1960b, Preliminary report on frequency and extent of flood inundation of Boulder Creek at Boulder, Colorado: U.S. Geo]. Survey open-file report, 28 p., 5 pls., 8 figs. Johnson, Arthur, 1960, Variations in surface elevations of the Nisqually Glacier, Mount Rainier, Washington [abs.] : J our. Geophys. Research, v. 65, no. 8, p. 2500. 1961, Glacier observations, Glacier National Park, Mon- tana, 1960: U.S. Geo]. Survey open-file report, 15 p., 1 fig. Johnson, A. 1., Morris, D. A., and Pril], R. C., 1960, Specific yield and related properties—an annotated bibliography, Part 1 : U.S. Geo]. Survey open-file report, 259 p. Johnson, C. R., 1960, Geology and ground water in the Platte- Republican Rivers watershed and the Little Blue River basin above Angus, Nebraska, with a section on Chemical quality of the ground water, by Robert Brennan: U.S. Geo]. Survey Water-Supply Paper 1489, 142 p., 4 pls., 11 figs. Johnson, K. E., Mason, R. A., and DeLuca, F. A., 1960, Ground— water map of the Oneco quadrangle, Connecticut-Rhode Is- land: Rhode Island Water Resources Coordinating Board Ground-Water Map 10. Johnson, P. W., 1960, Water in the Coconino sandstone for the Snowflake-Hay Hollow area, Navajo County, Arizona: U.S. Geo]. Survey open-file report. Johnson, R. B., 1960, Brief description of the igneous bodies of the Raton Mesa region, south-central Colorado, in Geol. Soc. America, jointly with Rocky Mtn. ASSOC. Geologists and Colorado Sci. Soc., Guide to the geology of Colorado: p. 117—120. 1961, Patterns and origin of radial dike swarms associ- ated with West Spanish Peak and Dike Mountain, south- central Colorado: Geol. Soc. America Bull., v. 72, no. 4, p. 579—590. Johnson, R. B., and Baltz, E. H., 1960, Probable Triassic rocks along the eastern front of Sangre de Cristo Mountains, south-central Colorado: Am. Assoc. Petroleum Geologists Bull., v. 44, no. 12, p. 1895—1902. Johnson, R. B., and Roberts, A. E., 1960, Depositional environ- ment of the coal-bearing formations of the Raton Mesa coal region, New Mexico and Colorado [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1899. Johnson, R. W., Jr., 1960a, A change in sedimentary facies in the Little Commonwealth area, Florence County, Wisconsin [abs.]: Inst. Lake Superior Geology, 6th ann. mtg, Mad- ison, Wis, April 1960, Program, p. 20. 1960b, Basement magnetic and gravity anomalies in southeastern Kentucky [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2017—2018. 1961, Dimensions and attitude of the peridotite in Clark Hollow, Union County, Tennessee—an aeromagnetic study: Southeastern Geology, v. 2, no. 3, p. 137—154. Jones, D. L., 1961, Muscle attachment impressions in a Creta- ceous ammonite: Jour. Paleontology, v. 35, no. 3, p. 502-504. Jones, I). L., and Gryc, George, 1960, Upper Cretaceous pelecy- pods of the genus I‘noceramus from northern Alaska: U.S. Geo]. Survey Prof. Paper 334-E, p. 149—165, pls. 15—23, figs. 30—33. A—168 Jones, P. H., and Subramanyam, V., 1961, Ground-water control in the Neyveli lignite field, South Arcot District, Madras State, India: Econ. Geology, v. 56, no. 2, p. 273—297, 14 figs. Kachadoorian, Reuben, 1960a, Engineering and surficial geology of the Nenana-Rex area, Alaska: U.S. Geol. Survey Misc. Geol. Inv. Map 1—307. 1960b, Engineering geology of the Katalla area, Alaska: U.S. Geol. Survey Misc. Geol. Inv. Map. I—308. Kachadoorian, Reuben, Lachenbruch, A. H., Moore, G. W., and Waller, R. M., 1960, Supplementary report on geologic investigations in support of phase II, Project Chariot in the vicinity of Cape Thompson, northwestern Alaska: U.S. Geol. Survey TEI—764, open-file report, 30 p., 6 figs., 2 tables. Kachadoorian, Reuben, and others, 1961, Geologic investigations in support of Project Chariot, Phase III, in the vicinity of Cape Thompson, northwestern Alaska—preliminary report: U.S. Geol. Survey TEI—779, open-file report, 104 p., 1 pl., 17 figs, 5 tables. Kam, William, 1961, Geology and ground—water resources of McMullen Valley, Maricopa, Yavapai, and Yuma Counties, Arizona: Arizona State Land Dept, Water Resources Rept. 8, 72 p., 17 figs. Kane, M. F., and Pakiser, L. G., 1961, Geophysical study of subsurface structure in southern Owens Valley, California: Geophysics, v. 26, no. 1, p. 12—26. Kaye, C. A., 1960, Surficial geology of the Kingston quadrangle, Rhode Island: U.S. Geol. Survey Bull. 1071—1, p. 341—396, pls. 32—32, figs. 46—62 [1961]. 1961, The disappearance of Gay Head: Vineyard Gazette, v. 116, no. 1, sec. 0, p. 1—5. Kaye, C. A., and Dunlap, J. C., 1960, Geology of the tunnels of the Caonillas and Caonillas Extension projects, Puerto Rico Water Resources Authority, Utuado area, Puerto Rico : Caribbean Geol. Cont, 2d, Puerto Rico 1959, Trans, p. 91— 95 [1961]. Kaye, C. A., Schnetzler, C. G., and Chase, J. N., 1961, A tektite from Gay Head, Martha’s Vineyard, Massachusetts: Geol. Soc. America Bull., v. 72, no. 2, p. 339—340. Keech, C. E, 1961, Water levels in observation wells in Ne- braska during 1960: Nebraska Water Survey Paper 9, 154 p., 21 figs. Keefer, W. R., 1960, Magnitude of crustal movement and depo- sition during Latest Cretaceous and early Tertiary time in the Wind River Basin, central Wyoming [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1901. Kehn, T. M., 1960, Previously unrecognized Devonian rocks and a major fault between the Schuylkill and the Susque- hanna Rivers, Pennsylvania [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2018—2019. Keller, A. S., Morris, R. H., and Detterman, R. 1., 1961, Geology of the Shaviovik and Sagavanirktok Rivers region, Alaska: U.S. Geol. Survey Prof. Paper 303—D, p. 169—222, pls. 21—26, figs. 26—32. Keller, G. V., 1960, Pulse-transient behavior of brine-saturated sandstones: U.S. Geol. Survey Bull. 1083—D, p. 111—129, figs. 36—44. Keller, G. V., and Frischknecht, F. C., 1960, Electrical resistivity studies on the Athabasca Glacier, Alberta, Canada: U.S. Natl. Bur. Standards Jour. Research, v. 64D, no. 5, p. 439—448. GEOLOGICAL SURVEY RESEARCH lQGl—SYNOPSIS OF RESULTS Keller, G. V., Plouff, Donald, and Zietz, Isidore, 1960, Geo- physical studies in support of geologic mapping in the Twin Buttes quadrangle, Arizona [abs.]: Mining Eng., v. 12, no. 12, p. 1249. Kennedy, V. C., 1960a, Geochemical studies in the Coeur d’Alene district, Shoshone County, Idaho, with a section on Geology, by S. W. Hobbs: U.S. Geol. Survey Bull. 1098—A, p. 1—55, pls. 1—7, figs. 1—20 [1961]. 1960b, Origin of uraniumwanadium deposits in the Lis- bon Valley area, San Juan County, Utah [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1904. Kimrey, J. 0., 1960a, Ground-water supply of Cape Hatteras National Seashore Recreational Area, Part 2: North Caro- lina Dept. Water Resources Rept. Inv. no. 2, 28 p., 2 pls., 4 figs. 1960b, Hydrology of a quarry-dewatering problem near New Bern, North Carolina [abs.] : Geol. Soc. America Bull., v. 71, no. 12,4 pt. 2, p. 2019. 1961, Ground-water supply for the Dare Beaches Sani- tary District: North Carolina Dept. Water Resources Rept. Inv. no. 3, 20 p., 1 pl., 4 figs. Kindsvater, C. E., 1961, Energy losses associated with abrupt enlargements in pipes, with special reference to the influ- ence of boundary roughness: U.S. Geol. Survey Water- Supply Paper 1369—B, p. 53—75, pl. 3, figs. 1—9. King, P. B., and Ferguson, H. W., 1960, Geology of northeastern— most Tennessee, with, a section on The description of the basement rocks, by Warren Hamilton: U.S. Geol. Survey Prof. Paper 311, 136 p., 19 pls., 27 figs. [1961]. King, R. R., and others, 1961, Bibliography of North American geology, 1958: U.S. Geol. Survey Bull. 1115, 592 p. Kleinhampl, F. J ., and Koteff, Carl, 1960, Botanical prospecting for uranium in the Circle Cliffs area, Garfield County, Utah : U.S. Geol. Survey Bull. 1085—0, p. 85—104, pls. 7—8, fig. 4. Knechtel, M. M., 1959, Stratigraphy of the Little Rocky Moun- tains and encircling foothills, Montana: U.S. Geol. Survey Bull. 1072—N, p. 723—752, pls. 52—53, figs. 32—33 [1960]. Koberg, G. E., 1960, Effect on evaporation of releases from reservoirs on Salt River, Arizona: Internat. Assoc. Sci. Hydrology Assoc. Bull. 19, p. 37—44, 4 figs. Kohout, F. A., 1960a, Cyclic flow of salt water in the Biscayne aquifer of southeastern Florida: Jour. Geophys. Research, v. 65, no. 7, p. 2133—2141, 10 figs. 1960b, Flow pattern of fresh and salt water in the Bis- cayne aquifer of Miami area, Florida: Internat. Assoc. Sci. HydrologyPub. 52, p. 440—448, 8 figs. Konizeski, R. L., McMurtrey, R. G., and Brietkrietz, Alex, 1961, Geology and ground-water resources of the northern part of the Deer Lodge Valley, Montana: Montana Bur. Mines and Geology Bull. 21, 24 p., 1 p1., 7 figs. Koschmann, A. H., 1960, Mineral paragenesis of Precambrian rocks in the Tenmile Range, Colorado: Geol. Soc. America Bull., v. 71, no. 9, p. 1357—1370. Koschmann, A. H., and Bergendahl, M. H., 1961, How about gold? Where mined and future production outlook: Mining World, v. 23, no. 1, p. 26—28. Krieger, R. A., and Hendrickson, G. E., 1960a, Effects of Greens- burg oilfield brines on the streams, wells, and springs of the upper Green River basin, Kentucky: Kentucky Geol. Survey Rept. Inv. 2, ser. 10, 36 p., 13 figs. 1960b, Some effects of waste oil-field brines on the streams, wells, and springs of the upper Green River basin, Kentucky [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2019—2020. LIST OF PUBLICATIONS Kulp, W. K., and Hopkins, H. T., 1960, Public and industrial water supplies of Kentucky: Kentucky Geol. Survey Inf. Circ., ser. 10, 102 p., 3 figs. Kunkel, Fred, 1960, Time, distance, and drawdown relation- ships in a pumped ground-water basin: U.S. Geol. Survey Circ. 433, 8 p., 4 figs. Kunkel, Fred, and Dutcher, L. C., 1960, Data on water wells in the Willow Springs, Gloster, and Chaffee areas, Kern County, California : California Dept. Water Resources Bull. 91—4, 85 p., 2 figs. Kunkel, Fred, and Upson, J. E., 1960, Geology and ground water in Napa and Sonoma Valleys, Napa and Sonoma Counties, California: U.S. Geol. Survey Water-Supply Paper 1495, 252 p., 5 pls., 7 figs. Lachenbruch, A. H., Brewer, M. 0., Greene, G. W., and Marshall, B. V., 1961, Temperature studies in permafrost [abs], in Symposium on temperature, its measurement and control in science and industry: Am. Inst. Physics, Columbus, March 1961, Program, p. 98. Lachenbruch, A. H., Greene, G. W., and Marshall, B. V., 1960, Geothermal studies at Ogotoruk Creek, AEC Project Chariot Test Site, northwestern Alaska [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2087. Ladd, H. S., and Schlanger, S. 0., 1960, Drilling operations on Eniwetok Atoll: U.S. Geol. Survey Prof. Paper 260—Y, p. 863L905, pls. 265—266, figs. 260—287. Lamey, C. A., 1961, Contact metasomatic iron deposits of Cali- fornia: Geol. Soc. America Bull., v. 72, no. 5, p. 669—678. LaMoreaux, P. E., 1960, Ground—water resources of the south—- a frontier of the nation‘s water supply: U.S. Geol. Survey Circ. 441, 9 p., 6 figs. [1961]. LaMoreaux, P. E., and Powell, W. J., 1961, Stratigraphic and structural guides to the development of water wells and well fields in a limestone terrane: Internat. Assoc. Sci. Hydrology Pub. 52, p. 363—375, 6 figs. Lang, J. W., and Boswell, E. H., 1961, Public and industrial water supplies in a part of northern Mississippi : Mississippi Geol. Survey Bull. 92, 104 p., 1 p1., 9 figs. Lang, S. M., Bierschenk, W. H., and Allen, W. B., 1960, Hydraulic characteristics of glacial outwash in Rhode Island: Rhode Island Water Resources Coordinating Board Hydrol. Bull. 3, 38 p. Langbein, W. B., and Iseri, K. T., 1960, General introduction and hydrologic definitions, Manual of hydrology, Part l—General surface-water techniques: U.S. Geol. Survey Water-Supply Paper 1541—A, p. 1—29. LaSala, A. M., Jr., and Johnson, K. E., 1960, Ground-water map of the Quonochontaug quadrangle, Rhode Island: Rhode Island Water Resources Coordinating Board Ground-Water Map 11. Lathram, E. H., 1960, Patterns of structural geology in the north- ern part of southeastern Alaska [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2064. Lathram, E. H., Loney, R. A., Berg, H. C., and Pomeroy, J. S., 1960, Progress map of the geology of Admiralty Island, Alaska: U.S. Geol. Survey Misc. Geol. Inv. Map I—323. Leggat, E. R., 1960a, Memorandum on ground-water conditions and suggestions for test drilling in the Logan Heights area, El Paso, Texas: U.S. Geol. Survey open-file report, 12 p., 3 figs. 1960b, Memorandum on the water-supply wells at Biggs Air Force Base, El Paso, Texas: U.S. Geol. Survey open- file report, 9 p., 4 figs. A—169 LeGrand, H. E., 1960a, Geology and ground-water resources of the Wilmington~New Bern area, North Carolina: North Carolina Dept. Water Resources, Ground Water Bull. 1, 80 p. 1960b, Metaphor in geomorphic expression: J our. Geology, v. 68, no. 5, p. 576—579. Lemke, R. W., 1960, Geology of the Souris River area, North Dakota: U.S. Geol. Survey Prof. Paper 325, 138 p., 16 pls., 17 figs. Leonard, A. R., 1960, Ground water in Oklahoma: Oklahoma Water Resources Board, 12 p., 6 figs. Leonard, A. R., and Berry, D. W., 1961, Geology and ground- water resources of southern Ellis County and parts of Trego and Rush Counties, Kansas: Kansas Geol. Survey Bull. 149, 156 p., 9 pls., 20 figs. Leonard, B. F., 1960, Reflectivity measurements with a Halli- mond visual microphotometer: Econ. Geology, v. 55, no. 6, p. 1306—1312. Leopold, L. B., Bagnold, R. A., Wolman, M. G., and Brush, L. M., Jr., 1960, Flow resistance in sinuous or irregular channels: U.S. Geol. Survey Prof. Paper 282-D, p. 111—134, pls. 3—4, figs. 68—80. Leopold, L. B., and Langbein, W. B., 1960, A primer on water: U .S. Geol. Survey Misc. Rept., 50 p., 16 figs. Leopold, L. B., and Wolman, M. G., 1960, River meanders: Geol. Soc. America Bull., v. 71, no. 6,-p. 769—794. Leppanen, O. E., and Harbeck, G. E., Jr., 1960, A test of the energy-balance method of measuring evapotranspiration: Internat. Union Geodesy and Geophysics, General Assem- bly, Helsinki 1960, Internat. Assoc. Sci. Hydrology, pub. no. 53, p. 428—437. Leve, G. W., 1961, Reconnaissance of the ground-water re- sources of the Fernandina area, Nassau County, Florida: Florida Geol. Survey Inf. Circ. 28, 24 p., 7 figs. Lewis, G. E., 1960a, Fossil vertebrates and sedimentary rocks of the Front Range foothills, Colorado, in Geol. Soc. Amer- ica, jointly with Rocky Mtn. Assoc. Geologists and Colo- rado Sci Soc., Guide to the geology of Colorado: p. 285—292. 1960b, Miocene vertebrates of the Mojave Desert [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1916. Lichtler, W. F., 1960, Geology and ground-water resources of Martin County, Florida: Florida Geol. Survey Rept. Inv. 23, 149 p., 26 figs. Lockwood, W. N., and Meisler, Harold, 1960, Illinoian outwash in southeastern Pennsylvania: U.S. Geol. Survey Bull. 1121—B, p. B-1—B-9, 5 figs. Loeltz, O. J ., 1960a, Cooperative ground-water investigation in Nevada, in Nevada Water Cont, 14th ann., Carson City 1960, Proc., Nevada Dept. Conserv. and Nat. Resources Rept., p. 74—76. 1960b, Source of water issuing from springs in Ash Meadow Valley, Nye County, Nevada [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1917—18. 1961, Progress report on the participation of the Water Resources Division of the U.S. Geological Survey in the Humboldt River research project: Nevada Dept. Conserv. and Nat. Resources, Humboldt River Research Proj., 2d Prog. Rept., p. 14-25. Lofgren, B. E., 1960a, Land subsidence adjacent to the White Wolf fault near Bakersfield, California [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1918. 1960b, Land subsidence in the Arvin-Maricopa area of the San Joaquin Valley, California, 1957-1959: U.S. Geol. Survey open-file report. A—170 Lofgren, B. E., and" Klausing, R. L., 1960, Land subsidence in the Tulare-Wasco area, California, 1957—1959: U.S. Geol. Survey open-file report. Long, A. T., J r., 1961, Geology and ground-water resources of Carson County and part of Gray County, Texas—progress report no. 1: Texas Board Water Engineers Bull. 6102, 45 p., 11 figs. Love, J. D., and Hoover, Linn, 1961, A summary of the geology of sedimentary basins of the United States, with reference to the disposal of radioactive wastes: U.S. Geol. Survey TEI—768, open-file report, 89 p., 2 figs. Love, J. D., McGrew, P. 0., and Thomas, H. D., 1961, Relation of latest Cretaceous and Tertiary deposition and deforma- tion to oil and gas occurrences in Wyoming [abs]: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 3, p. 415. Lovering, T. S., 1960, Current practice and trends in mineral exploration [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2102. 1961, Sulfide ores formed from sulfide-deficient solutions: Econ. Geology v. 56, no. 1, p. 68—99. Lovering, T. S., and Morris, H. T., 1960, U.S. Geological Survey studies and exploration, Part 1, in Bush, J. B., Cook, D. R., Lovering, T. S., and Morris, H. T., The Chief Oxide-Burgin area discoveries, East Tintic district, Utah, a case history: Econ. Geology, v. 55, no. 6, p. 1116—1147. Lovering, T. S., and Shepard, A. 0., 1960, Hydrothermal argil- lic alteration on the Helen Claim, East Tintic district, Utah; Natl. Conf. Clays and Clay Minerals, 8th, Norman, Okla., 1959, Proc., p. 193—202. Lusczynski, N. J ., and Swarzenski, W. V., 1960, Position of the salt-water body in the Magothy( ?) formation in the Cedar- hurst-Woodmere area of southwestern Nassau County, Long Island, N.Y.: Econ. Geology, v. 55, no. 8, p. 1739—1750, 4 figs. Lyddan, R. H., 1961, Geodesy and cartography program for Antarctica: Natl. Acad. Sci-Natl. Research Council Pub. 878, p. 67-72. Mabey, D. B.,, Pakiser, L. G., and Kane, M. F., 1960, Gravity studies in the Basin and Range province [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1920. McCall, J. E., 1961, Stream—gaging network in the United States: Am. Soc. Civil Engineers Jour., Hydraulics Div., v. 87, no. HY2, p. 79—95. McCall, J. E., and Lendo, A. C., 1960, Surface water supply of New Jersey, 1950—55: New Jersey Dept. Conserv. and Econ. Devel., Div. Water Policy and Supply, Spec. Rept. 16, 405 p. McCulloh, T. H., 1960, Geologic map of the Lane Mountain quadrangle, California: U.S. Geol. Survey open-file report. McDonald, 0. C., 1961, Investigation of the water resources of the lower Colorado River area: U.S. Geol. Survey open-file report, 5 p. Macdonald, G. A., Davis, D. A., and Cox, D. G., 1960, Geology and ground-water resources of the island of Kauai, Hawaii: Hawaii Div. Hydrography Bull. 13, 212 p., 10 pls., 38 figs. McGuinness, C. L., 1960, Ground water—a mixed blessing: Internat. Geol. Cong, 2lst, Copenhagen 1960, pt. 20, sec. 20, Proc., p. 7—16. Mack, Seymour, 1960, Geology and ground-water features of Shasta Valley, Siskiyou County, California: U.S. Geol. Survey Water-Supply Paper 1484, 115 p., 2 pls., 12 figs. McKee, E. D., 1961a, A report on typhoon efiects upon Jaluit Atoll, IV. Island structures and their modification: Atoll Research Bull. 75, p. 37—40. GEOLOGICAL SURVEY RESEARCH 1961~SYNOPSIS OF RESULTS McKee, E. D., 1961b, A report on typhoon effects upon Jaluit Atoll, V. Removal of fine sediments from islets: Atoll Research Bull. 75, p. 41—43. 1961c, A report on typhoon effects upon Jaluit Atoll, VI. Ground water: Atoll Research Bull. 75, p. 43415. McKeown, F. A., and Dickey, D. D., 1961, Interim report on geologic investigations of the U129 tunnel system, Nevada Test Site, Nye County, Nevada: U.S. Geol. Survey TEI—772, open-file report, 16 p., 8 figs, 6 tables. MacKevett, E. M., Jr., 1960, Geology and ore deposits of the Kern River uranium area, California: U.S. Geol. Survey Bull. 1087—F, p. 169—222, pls. 19—25, figs. 21—24. MacKichan, K. A., and Kammerer, J. C., 1961, Preliminary estimate of water used in southeast river basins, 1960: U.S. Geol. Survey Circ. 449, 10 p., 1 fig. McLaughlin, T. G., Burtis, V. M., and Wilson, W. W., 1961, Records and logs of selected wells and test holes, and chemical analyses of ground water from wells and mines, Huerfano County, Colorado: Colorado Water Conserv. Board, Ground Water Series, Basic—data Rept. No. 4, 26 p., '1 fig., 1 pl. MacNeil, F. S., 1960, Tertiary and Quaternary Gastropoda of Okinawa: U.S. Geol. Survey Prof. Paper 339, 148 p., 21 pls., 17 figs. [1961] Malde, H. E., 1960, Geologic age of the Claypool site, northeast- ern Colorado: Am. Antiquity, v. %, no. 2, p. 236—243. Mallory, W. W., 1960, Outline of Pennsylvanian stratigraphy in Colorado, in Geol. Soc. America, jointly with Roeky Mtn. Assoc. Geologists and Colorado Sci. Soc., Guide to the geology of Colorado: p. 23~33. Mapel, W. J ., 1959, Geology and coal resources of the Buffalo- Lake DeSmet area, Johnson and Sheridan Counties, Wye ming: U.S. Geol. Survey Bull. 1078, 148 p., 23 pls., 6 figs. [1961]. Marcher, M. V., and Steams, R. G., 1960, Lithology and source of the Tuscaloosa formation in western Tennessee [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2020. Marine, I. W., 1960, Water-supply possibilitiles at Capitol Reef National Monument, Utah: U.S. Geol. Survey open-file report. Markward, E. L., 1961, Geochemical prospecting abstracts, Jan- uary 1955—June 1957 : U.S. Geol. Survey Bull. 1098—B, p. 57—160. Marsh, 0. T., 1960a, A rapid and accurate contour inberpolator: Econ. Geology, v. 55, no. 7, p. 1555—1560, 3 figs. 1960b, Relation of Bucatunna clay member of Byram formation to geology and ground water of westernmost Florida [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2020. 1961, Water Witching: All Florida Magazine, Mar. 12 issue, p. 6—7, 4 figs. Martinez, Prudencio, and Senftle, F. E., 1960, Efiect of crystal thickness and geometry on the alpha-particle resolution of CsI(T1) : Rev. Sci. Instruments, v. 31, no. 9, p. 974—977. Mason, A. G., Elias, M. M., Hackman, R. J., and Olson, A. R.. 1960, Terrain study and map of the surface of the moon [abs] : Jour Geophys. Research, v. 65, no. 8, p. 2510. Mason, A. G., and Hackman, R. J ., 1960, Physiographic divisions and photogeologic map of the moon [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2103. Mason, C. G., 1961, Ground-water geology of the Hickory sand- stone member of the Riley formation, McCulloch County, Texas: Texas Board Water Engineers Bull. 6017, 84 p., 15 figs. LIST OF PUBLICATIONS Masursky, Harold, 1960, Welded tufts in the northern Toiyabe Range, Nevada [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1922. Matthes, F. E., 1960, Reconnaissance of the geomorphology and glacial geology of the San Joaquin Basin, Sierra Nevada, California: U.S. Geol. Survey Prof. Paper 329, 62 p., 2 pls., 48 figs. Mattson, P. H., 1960, Notes on the stratigraphy and structure of southwestern Puerto Rico [abs]: Caribbean Geol. Conf., 2d, Puerto Rico 1959, Trans., p. 99 [1961]. Maughan, E. K., and Wilson, R. F., 1960, Pennsylvanian and Permian strata in southern Wyoming and northern Col- orado, in Geol. Soc. America, jointly with Rocky Mtn. Assoc. Geologists and Colorado Sci. Soc., Guide to the geology of Colorado: p. 34—42. May, H. G., 1961, Ground-water resources of LaSalle Parish, Louisiana: Louisiana Dept. Public Works and LaSalle Parish Devel. Board, p. 56—57. May, Irving, 1961, A simplified mercury thermoregulator: Chem- ist-Analyst, v. 50, no. 1, p. 24. Merewether, E. A., 1960a, Geologic map of the igneous and meta- morphic rocks of Colorado showing location of uranium deposits: U.S. Geol. Survey Misc. Geol. Inv. Map I—309. 1960b, Geologic map of the igneous and metamorphic rocks of Wyoming showing location of uranium deposits: U.S. Geol. Survey Misc. Geol. Inv. Map I—310. 1960c, Geologic map of the igneous and metamorphic rocks of Montana showing location of uranium deposits: U.S. Geol. Survey Misc. Geol. Inv. Map 1—311. Meyers, T. R., and Bradley, Edward, 1960, Suburban and rural water supplies in southeastern New Hampshire: New Hampshire State Planning and Devel. Comm. Mineral Re- sources Survey, pt. 18, 31 p., map. Meyrowitz, Robert, and Beasley, J. B., 1961, Photometric titra- tion attachment for use with Beckman Model B spectropho- tometer: Chemist-Analyst, v. 50, no. 2, p. 56. Meyrowitz, Robert, Cuttitta, Frank, and Levin, Betsy, 1960, N,N-Dimethylformamide, a new diluent for methylene iodide heavy liquid: Am. Mineralogist, v. 45, nos. 11—12, p. 1278— .1280. Miesch, A. T., and Riley, L. B., 1960, Basic statistical measures used in geochemical investigations of Colorado Plateau uranium deposits [abs] : Mining Eng., v. 12, no. 12, p. 1248. 1961, Basic statistical measures used in geochemical in- vestigations of Colorado Plateau uranium deposits: Am. Inst. Mining Metall. Engineers, Preprint no. 61137, 11 p. Miesch, A. T., Shoemaker, E. M., Newman, W. L., and Finch, W. I., 1960, Chemical composition as a guide to the size of sandstone-type uranium deposits in the Morrison forma- tion on the Colorado Plateau: U.S. Geol. Survey Bull. 1112—B, p. 17—61, figs. 3—14. Milkey, R. G., 1960, Infrared spectra of some tectosilicates: Am. Mineralogist, v. 45, nos. 9-10, p. 990-1007. Miller, D. J., 1961a, Geology of the Katalla district, Gulf of Alaska Tertiary province, Alaska: U.S. Geol. Survey open- file report. 1961b, Geology of the Lituya district, Gulf of Alaska Tertiary province, Alaska: U.S. Geol. Survey open-file report. 1961c, Geology of the Malaspina district, Gulf of Alaska Tertiary province, Alaska: U.S. Geol. Survey open-file report. A-171 Miller, D. J., 1961d, Geology of the Yakataga district, Gulf of Alaska Tertiary province, Alaska: U.S. Geol. Survey open- file report. 1961e, Geology of the Yakutat district, Gulf of Alaska Tertiary province, Alaska: U.S. Geol. Survey open-file report. Milton, Charles, Chao, E. C. T., Fahey, J. J., and Mrose, M. E., 1960, Silicate mineralogy of the Green River formation of Wyoming, Utah, and Colorado: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 21, sec. 21, Proc., p. 171—184. Milton, Charles, and Fahey, J. J., 1960, Green River mineral- ogy—a historical account, in Overthrust belt of southwest- ern Wyoming and adjacent areas, Wyoming Geol. Assoc. Guidebook 15th Ann. Field Conf., 1960: p. 159—162. Milton, Charles, Ingram, B. L., and Blade, L. V., 1960, Kim- zeyite, a zirconium garnet from Magnet Cove, Arkansas [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1930. Milton, D. J ., 1960a, Geology of the Old Speck Mountain quad— rangle [Maine], Trip D, in New England Intercollegiate Geol. Conf. Guidebook 52d ann. mtg, Rumford, Maine, 1960: p. 25—32. 1960b, Sphene-flecked diorite from Maine [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1931. Mink, J. F., 1960a, Distribution of rainfall in the leeward Koolau Mountains, Oahu, Hawaii: J our. Geophys. Research, v. 69, no. 9, p. 2869—2876. 1960b, Some geochemical aspects of sea-water intrusion in an island aquifer: Internat. Assoc. Sci. Hydrology Pub. 52, p. 424—439. Miser, H. D., and Hendricks, T. A., 1960, Age of Johns Valley shale, Jackfork sandstone, and Stanley shale: Am. Assoc. Petroleum Geologists Bull., v. 44, no. 11, p. 1829—1832. Moore, G. W., 1960a, Geology of Carlsbad Cavens, New Mexico, in Spangle, P. F., ed., A guidebook to Carlsbad Caverns National Park: Washington, DC, Natl. Speleol. Soc., Guide Book series no. 1, p. 10-18. 1960b, Introduction to the origin of limestone caves, in Moore, G. W., ed., Origin of limestone caves; a symposium with discussion: Natl. Speleol. Soc. Bull., v. 22, pt. 1, p. 3—4. Moore, J. G., and Hopson, C. A., 1961, The Independence dike swarm in eastern California: Am. Jour. Sci., v. 259, no. 4, p. 241—259 Morimoto, Nobuo, Appleman, D. E., and Evans, Howard T., Jr., 1960, The crystal structures of clinoenstatite and pigeonite: Zeitschr. Kristallographie, v. 114, p. 120—147. Morris, D. A., and Babcock, H. M., 1960, Geology and ground- water resources of Platte County, Wyoming, with, a section ‘ on Chemical quality of the water, by R. H. Langford: U.S. Geol. Survey Water-Supply Paper 1490, 195 p., 4 pls., 20 figs. [1961]. Moulder, E. A., 1960a, A plan for the practical management of the water resources in an alluvial valley: U.S. Geol. Survey open-file report, 7 p., 4 figs. 1960b, Occurrence of ground water in the Ogallala and several consolidated formations in Colorado: Colorado Water Conserv. Board, Ground Water Ser. Circ. 5, 8 p. Moulder, E. A., Klug, M. F., Morris, D. A., and Swenson, F. A., 1960‘, Geology and ground-water resources of the lower Little Bighorn River valley, Big Horn County, Montana, with special reference to the drainage of waterlogged lands, with a section on Chemical quality of the water, by R. A. Krieger: U.S. Geol. Survey Water-Supply Paper 1487, 223 p., 13 pls., 37 figs. A—172 Moyle, W. R. Jr., 1960, Ground-water inventory for 1959, Ed- wards Air Force Base, California: U.S. Geol. Survey open- file report, 35 p., 7 figs. ‘ Mrose, M. E., 1961, Vernadskite discredited: pseudomorphs of antlerite after doleorphanite: Am. Mineralogist, v. 46, nos. 1—2, p. 146—154. . Mrose, M. E., and Appleman, D. E., 1960, Crystal structure of fairfieldite, Ca2(Mn,Fe) (Pol)s-2H20: [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1932. Mrose, M. E., Chao, E. C. T., Fahey, J. J., and Milton, Charles, 1961, Norsethite, BaMg(CO:.)z, a new mineral from the Green River formation, Wyoming: Am. Mineralogist, v. 46, nos. 3—4, pts. 1—2, p. 420—429. Muir, K. S., Merritt, P. M., and Miller, G. A., 1960, Water levels in observation wells in Santa Barbara County, California, in 1959: U.S. Geol. Survey open-file report, 21 p., 9 figs. Mullens, T. E., 1960, Geology of the Clay Hills area, San Juan County, Utah: U.S. Geol. Survey Bull. 1087—H, p. 259—336, pl. 27, figs. 26—27. j Mundorff, M. J ., 1960, Results of test drilling and aquifer tests in the Snake River basin, Idaho, in 1958: U.S. Geol. Survey open-file report, 93 p., 50 figs. Mundorff, M. J ., Crostwaite, E. G., and Kilburn, Chabot, 1960, Ground water for irrigation in the Snake River basin in Idaho: U.S. Geol. Survey open-file report. Murata, K. J., 1960, Occurrence of CuCl emmission in volcanic flames: Am. Jour. Sci., v. 258, no. 10, p. 769—772. 1961, Vigil for disaster, 1961: GeoTimes, v. 5, no. 5, p. 12—13. Mussey, 0. D., 1961a, How much water do we have? How much water do we need?: Water Works Eng., v. 114, no. 4, p. 280—283, 6 figs. 1961b, Water—its role in mining and beneficiating iron ore: New York, Am. Inst. Mining Metall. Engineers, Soc. Mining Engineers Preprint 61 H 81, 8 p., 3 figs. Myers, A. T., and Hamilton, J. 0., 1960, Rhenium in plant sam- ples from the Colorado Plateau [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1934. Myers, A. T., Havens, R. G., and Dunton, P. J., 1961, A spectro- chemical method for the semiquantitative analysis of rocks, minerals, and ores: U.S. Geol. Survey Bull. 1084—1, p. 207— 229, fig. 31. Myers, A. T., and Wood, W. H., 1960, Ceramic mills in a paint mixer for preparation of multiple rock samples: Appl. Spectroscopy, v. 14, no. 5, p. 136—137. Myers, D. A., 1960a, Stratigraphic distribution of some Pennsyl- vania ,Fusulinidae from. Brown and Coleman Counties, Texas: U.S. Geol. Survey Prof. Paper 315—0, p. 37~53, pls. 15—24, figs. 9—10. 1960b, Stratigraphy of the Cisco group, Wayland quadrangle, Stephens and Eastland Counties, Texas, in A traverse of post-Avis Cisco rocks, Brazos valley, north central Texas: Soc. Econ. Paleontologists and Mineralo- gists Field Trip Guidebook, April 1960, p. 47—59. Myers, W. B., 1960, Structural deformation accompanying the earthquake of August 17, 1959', in southwest Montana [abs.] : Jour. Geophys. Research, v. 65, no. 8, p. 2513. Nace, R. L, 1960, Contribution of geology to the problems of radioactive-waste disposal, in International Atomic Energy Agency, Disposal of radioactive wastes: Sci. Conf. Disposal Radioactive Wastes, Principality Monaco, Nov. 16—21, 1959, Proc., v. 2, p. 457—480. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Neuman, R. B., 19603., Geology of the Wildwood quadrangle, Tennessee: U.S. Geol. Survey Geol. Quad. Map GQ—130 [1961]. 1960b, Sedimentation in the 0coee series, Great Smoky Mountains [abs.] : Washington Acad. Sci. Jour., v. 50, no. 7, p. 2. Neuman, R. B., and Wilson, R. L., 1960, Geology of the Block- house quadrangle, Tennessee: U.S. Geol. Survey Geol. Quad. Map GQ—131 [1961]. Newcomb, R. C., 1960, Summary of ground water in subareas of the Snake River basin in Oregon south of the Wallowa Mountains: U.S. Geol. Survey open-file report, 14 p., 1 fig. Newcome, Roy, Jr., 1960, Ground-water resources of the Red River Valley alluvium in Louisiana: Louisiana Dept. Con- serv., Geol. Survey and Louisiana Dept. Public Works, Water Resources Pamph. 7, 21 p., Norton, J. J ., and Redden, J. A., 1960, An unusual structure as- sociated with rock creep in the Black Hills, South Dakota: I, Geol. Soc. America Bull., 71, no. 7, p. 1109—1112. Norvitch, R. F., 1960, Ground water in alluvial channel deposits, Nobles County, Minnesota: Minnesota Dept. Conserv. Div. Waters Bull. 14, 23 p., 2 figs. Oborn, E. T., 1960a, A survey of pertinent biochemical litera- ture: U.S. Geol. Survey Water-Supply Paper 1459-F, p. 111— 190, figs. 12—17. 1960b, Iron content of selected water and land plants: U.S. Geol. Survey Water-Supply Paper 1459—G, p. 191—211, pl. 1, figs. 18—20. Oborn, E. T., and Hem, J. D., 1961, Microbiologic factors in the solution and transport of iron: U.S. Geol. Survey Water- Supply Paper 1459—H, p. 213—235, figs. 21—22. O’Connor, H. G., 1960, Geology and ground-water resources of Douglas County, Kansas: Kansas Geol. Survey Bull. 148, 200 p., 9 pl., 10 figs. Odom, O. B., 1961, Effects of temporary surface loading and changes in atmospheric pressure on artesian water levels in wells in Savannah area, Georgia: Georgia Geol. Survey Mineral Newsletter, v. 14, no. 1, p. 28—29, 2 figs. Ogata, Akio, 1961, Transverse diffusion in saturated isotopic granular media: U.S. Geol. Survey Prof. Paper 411—B, p. B-1—B-8, 3 figs. Okamura, R. T., and Forbes, J. C., 1961, Occurrence of silicified wood in Hawaii: Am. Jour. Sci., v. 259, no. 3, p. 229—230. Oliver, W. A., Jr., 1960a, Devonian rugose corals from northern Maine: U.S. Geol. Survey Bull. 1111—A, p. 1—23, pls. 1—5, figs. 1—2. 1960b, Inter- and intracolony variation in Acinophylmm [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1937. Oliver, W. A., Jr., and Quinn, A. W., 1960, Geology of the Nar- ragansett Basin, Rhode Island and Masachusetts [abs.]: Washington Acad. Sci. J our., v. 50, no. 7, p. 6—8. Olson, J. C., and Hedlund, D. C., 1960, Log No. S25, Poncha Springs to Montrose via U.S. 50, in Rocky Mtn. Assoc. Geologists, Geological road logs of Colorado: p. 81—86. Oriel, S. S., and Craig, L. C., 1960, Lower Mesozoic rocks in Colorado, in Geol. Soc. America, jointly with Rocky Mtn. Assoc. Geologists and Colorado Sci. Soc, Guide to the geology of Colorado : p. 43-58. Osterwald, F. W., 1961, Critical review of some tectonic problems in Cordilleran foreland: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 2, p. 219-237. O’Sullivan, R. B., 1961, Geologic map of the Cedar Mesa- Boundary Butte area, San Juan County, Utah: U.S. Geol. Survey open-file report, 11 p., 4 figs. LIST OF PUBLICATIONS Overstreet, W. C., and Bell, Henry, III, 1960a, Geochemical and heavy-mineral reconnaissance of the Concord SE quad— rangle, Cabarrus County, North Carolina: U.S. Geol. Survey Mineral'Inv. Field Studies Map MF—235. 1960b, Notes on the Kings Mountain belt in Laurens County, South Carolina: South Carolina State Devel. Board, Div. Geology, Geol. Notes, v. 4, no. 4, p. 27—30. Overstreet, W. C., Overstreet, E. F., and Bell, Henry, III, 1960, Pseudomorphs of kyanite near Winnsboro, Fairfield County, South Carolina: South Carolina State Devel. Board, Div. Geology, Geol. Notes, v. 4, no. 5, p. 35—39. Page, L. R., 1960, The sources of uranium in ore deposits: Internat. Geol. Cong., 2lst, Copenhagen 1960, pt. 15, sec. 15, Proc., p. 149—164. Page, R. W., 1961, Ground-water conditions during 1959 at the Naval Air Missile Test Center, Point Mugu, California: U.S. Geol. Survey open-file report, 32 p., 5 figs. Page, R. W., and Moyle, W. R., Jr., 1960, Data on water wells in the eastern part of the middle Mojave Valley area, San Bernardino County, California : California Dept. Water Re- sources Bull. 91—3, 38 p., 2 figs. Pakiser, L. 0., 1960, Gravity in volcanic areas, California and Idaho [abs] : J our. Geophys. Research,'v. 65, no. 8, p. 2515. Palmer, A. R., 1960a, Early Late Cambrian stratigraphy of the United States [abs] : Washington Acad. Sci. J our., v. 50, no. 7, p. 8—9. 1960b, Some aspects of the early Upper Cambrian strati- graphy of White Pine County, Nevada, and vicinity, in Guidebook to the geology of central Nevada, Intermountain Assoc. Petroleum Geologists, 11th Ann. Field Conf., 1960: p. 53—58. 1960c, Stratigraphic range and significance of the Cam- brian agnostid genus Glypaag'nostus [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1941. Palmquist, W. N., Jr., and Hall, F. T., 1960a, Availability of ground water in Boone, Campbell, Grant, Kenton, and Pendleton Counties, Kentucky: U.S. Geol. Survey Hydrol. Inv. Atlas HA—15. 1960b, Availability of ground water in Bracken, Harrison, Mason Nicholas, and Robertson Counties, Kentucky: U.S. Geol. Survey Hydrol. Inv. Atlas HA—16. 1960c, Availability of ground water in Lewis and Rowan Counties, Kentucky: U.S. Geol. Survey Hydrol. Inv. Atlas HA—17. 1960d, Availability of ground water in Boyle, Gerrard, Lincoln, and Mercer Counties, Kentucky: U.S. Geol. Survey Hydrol. Inv. Atlas HA—20. 1960e, Availability of ground water in Bullitt, Jefferson, and Oldham Counties, Kentucky: U .S. Geol. Survey Hydrol. Inv. Atlas HA—22. 1960f, Availability of ground water in Bourbon, Fayette, Jessamine, and Scott Counties, Kentucky: U.S. Geol. Survey Hydrol. Inv. Atlas HA—25. 1961, Reconnaissance of ground-water resources in the Blue Grass region, Kentucky: U.S. Geol. Survey Water- Supply Paper 1533, 39 p., 3 pls., 8 figs. Pankey, Titus, J r., 1960, Anisotropy of the magnetic susceptibil- ity of gallium : J our. Appl. Physics, v. 31, no. 10, p. 1802—1804. Patterson, E. D., 1960, Ellipsoidal structures in dark-gray shale in western Pennsylvania [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2023. A—173 Pauszek, F. H., 1960, Chemical and physical quality of water resources in Connecticut (progress report): Connecticut Water Resources Comm, Water Resources Bull. no. 1, 79 p. Pearre, N. 0., 1961, Mineral deposits of Maryland excluding fuels, sand, and gravel: U.S. Geol. Survey Mineral Inv. Re- source Map MR—12. Pearre, N. C., and Hey], A. V., Jr., 1960, Chromite and mineral deposits in serpentine rocks of the Piedmont Upland, Mary- land, Pennsylvania, and Delaware: U.S. Geol. Survey Bull. 1082—K, p. 707—833, pls. 40—47, figs. 65—70 [1961]. Pease, M. H., J r., and Briggs, R. P., 1960, Geology of the Comerio quadrangle, Puerto Rico: U.S. Geol. Survey Misc. Geol. Inv. Map I—320 [1961]. Peckham, A. E., 1961, Heavy minerals of the Miocene Harrison formation in northwestern Nebraska: Jour. Sed. Petrology, v. 31, no. 1, p. 52—62, 2 figs. Pecora, W. T., 1960, Coesite craters and space geology: Geo- Timos, v.5, no. 2, p. 16—19. Peselnick, Louis, and Meister, Robert, 1961, Acoustic relaxation in chromium: Jour. Geophys. Research, v. 66, no. 6, p. 1957—1961. Peselnick, Louis, and Outerbridge, W. F., 1961, Internal friction in shear and shear modulus of Solenhofen limestone over a frequency range of 10 7 cycles per second: J our. Geophys. Research, v. 66, no. 2, p. 581—588. Petersen, R. G., 1961, Preliminary geologic map of the Paria Plateau SE quadrangle, Coconino County, Arizona: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—196. Petersen, R. G., and Wells, J. D., 1960, Preliminary geologic map of the Emmett Wash NW quadrangle, Coconino County, Arizona: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—197 [1961]. Peterson, D. W., 1960, Geology of the Haunted Canyon quad- rangle, Arizona: U.S. Geol. Survey Geol. Quad. Map GQ—128. 1961, Dacitic ash-flow sheet near Superior and Globe, Arizona: U.S. Geol. Survey open-file report, 130 p., 7 pls., 32 figs, 6 tables. Peterson, N. P., 1961, Preliminary geologic map of the Final Ranch quadrangle, Arizona : U.S. Geol. Survey Mineral Inv. Field Studies Map MF—81. Peterson, W. C., 1960, Water-resources summary for southern California, 1959: U.S. Geol. Survey Circ. 429, 26 p., 8 figs. Peterson, W. L., and Scott, G. R., 1960, Precambrian rocks and structure of the Platte Canyon and Kassler quadrangles, Colorado, in Geol. Soc. America, jointly with Rocky Mtn. Assoc. Geologists and Colorado Sci. Soc., Guide to the geology of Colorado : p. 181—183. Péwé, Troy L., 1960a, Glacial history of the McMurdo Sound region, Antarctica: Internat. Geophysical Year Bull. no. 36, p. 1—7. 1960b, Glacial history of the McMurdo Sound region, Antarctica: Internat. Geol. Cong., 21st, Copenhagen 1960, pt. 4, Proc., p. 71—80. 1960c, Multiple glaciation in the McMurdo Sound region Antarctica—a progress report: Jour. Geology, v. 68, p. 498—514. Péwé, T. L., and Burbank, Lawrence, 1960, Multiple glaciation in the Yukon-Tanana Upland, Alaska: a photogeologic inter- pretation [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2088. Phoenix, D. A., and Stacy, J. R., 1960, Techniques of geologic il- lustration [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1944. A—174 Picciotto, E., de Maere, X., and Friedman, Irving, 1960, On the isotopic composition and temperature of formation of Ant- arctic snows: Nature, v. 187, no. 4740, p. 857—859. Pierce, W. G., 1960, Reef Creek detachment fault in northwestern Wyoming [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1944. Pinckney, D. M., and Becraft, G. E., 1961, Preliminary geologic map of the southwest quarter of the Boulder quadrangle, Montana : U.S. Geol. Survey Mineral Inv. Field Studies Map MF—187. Piper, A. M., 1960, Interpretation and current status of ground- water rights: U.S. Geol. Survey Circ. 432, 10 p. Plebuch, R. 0., 1960, The Fall Line divides state into equal parts: Little Rock, Arkansas, Gazette, July 3, 1960, p. 6D, 1 fig. Poland, J. E., 1960a, Land subsidence due to withdrawal of fluids—part 2 [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1945. ’ 1960b, Land subsidence in the San Joaquin Valley and its effect on estimates of ground-water resources: Internat. Assoc. Sci. Hydrology Pub. 52, p. 324—335, 7 figs. Pollock, S. J., 1960, Ground-water map of the North Scituate quadrangle, Rhode Island: Rhode Island Water Resources Coordinating Board Ground-Water Map 12. Pommer, A. M., and Breger, I. A., 1960a, Potentiometric titra- tion and equivalent weight of humic acid: Geochim. et Cosmochim. Acta, v. 20, no. 1, p. 30—44. 1960b, Equivalent weight of humic acid from peat: Geo- chim. et C‘osmochim. Acta, v. 20, no. 1, p. 45—50. Popenoe, W. P., Imlay, R. W., and Murphy, M. A., 1960, Cor- relation of the Cretaceous formations of the Pacific Coast (United States and northwestern Mexico) : Geol. Soc. America Bull. v. 71, no. 10, p. 1491—1540. Pratt, W. P., and Jones, W. R., 1961, Montoya dolomite and Fusselman dolomite in Silver City region, New Mexico: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 4, p. 484—500. Prescott, G. C., 1960, The geology of Maine and its relation to water supplies: Maine Water Utilities Assoc. J our., v. 36, no. 5, p. 18—35, 7 figs. Price, 0. E., 1961, Artificial recharge through a well tapping basalt aquifers, Walla Walla area, Washington: U.S. Geol. Survey Water-Supply Paper 1594—A, p. A-1—A-33, figs. 1—4. Price, W. E., Jr., 1960, Relation of geologic source, depth of well, and topographic location to the yield of wells in the eastern coal field, Kentucky [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1947. Pride, R. W., Meyer, F. W., and Cherry, R. N., 1961, Interim report on the hydrologic features of the Green Swamp area in central Florida: Florida Geol. Survey Inf. Circ. no. 26, 96 p., 22 figs. Rainwater, F. H., and Thatcher, L. L., 1960, Methods for col- lection and analysis of water samples: U.S. Geol. Survey Water-Supply Paper 1454, 301 p., 17 figs. Randall, A. D., Bierschenk, W. E., and Hahn, G. W., 1960, Ground-water map of the Voluntown quadrangle, Connec- ticut-Rhode Island: Rhode Island Water Resources 00- ordinating Board Ground-Water Map 13. Rantz, S. E., 1961a, Flow of springs and small streams in the Tecolote Tunnel area of Santa Barbara County, California: U .S. Geol. Survey open-file report, 282 p., 9 figs., 1 map. 1961b, Surges in natural channels [abs] : Jour. Geophys. Research, v. 66, no. 5, p. 1557. 1961c, Surges in natural stream channels: U.S. Geol. Survey Water-Supply Paper 1369—c, p. 77—90, figs. 10—13. GEOLOGICAL SURVEY RESEARCH 1961—SY'NOPSIS OF RESULTS Rapp, J. R., 1960a, Availability of ground water of irrigation on the San Ildefonso Pueblo Grant, Santa Fe County, New Mexico, with a summary of the well drilling: U.S. Geol. Survey open-file report, 20 p., 1 fig. 1960b, Reconnaissance of ground water for irrigation, Acoma Indian Reservation, Valencia County, New Mexico: U.S. Geol. Survey open-file report, 26 p., 2 figs. Rasmussen, W. C., Wilkens, R. A., and Beall, R. M., 1960, Water resources of Sussex County, Delaware, with a section on Salt-water encroachment at Lewes: Delaware Geol. Sur- vey Bull. 8, 228 p., 10 pls. Ran, J. L., 1960, Stratigraphy of the Three Forks shale in south- western Montana [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1952. Ray, L. L., 1960, Relation of the profile of weathering to me— chanical analyses of loess [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1953. Ray, R. G., 1960, Aerial photographs in geologic interpretation and mapping: U.S. Geol. Survey Prof. Paper 373, 230 p., 116 figs. [1961]. Reeder, H. 0., and others, 1960a, Ground-water levels in New Mexico, 1956: New Mexico State Engineer Tech. Rept. 19, 251 p., 19 figs. 1960b, Changes in water levels in 1955 and annual water- level measurements in January and February 1956 in observation wells in New Mexico: New Mexico State Engi- neer Tech. Rept. 16, 145 p., 31 figs. Reeside, J. B., Jr., and Cobban, W. A., 1960, Studies of the Mowry shale (Cretaceous) and contemporary formations in the United States and Canada: U.S. Geol. Survey Prof. Paper 355, 126 p., 58 pls., 30 figs. Repenning, C. A., 1961, Geologic sumary of the Central Valley of California, with reference to disposal of liquid radio- active waste: U.S. Geol. Survey TEI—769, open-file report, 69 p., 14 figs. Richards, P. W., and Nieschmidt, C. L., 1961, The Bighorn ' dolomite and correlative formations in southern Montana and northern Wyoming: U.S. Geol. Survey Oil and Gas Inv. Map. OM—202. Richardson, E. V., Simons, D. B., and Posakony, G. J., 1961, Sonic depth sounder for laboratory and field use: U.S. Geol. Survey Circ. 450, 7 p., 4 figs. Richmond, G. M., 1960, Glaciation of the east slope of Rocky Mountain National Park, Colorado: Geol. Soc. America Bull., v. 71, no. 9, p. 1371—1382. Richter, D. H., and Murata, K. J ., 1960, Xenolithic nodules in the 1800—1801 Kaupuleku flow of Hualalai Volcano and their petrologic implication [abs]: Hawaiian Acad. Sci., 35th ann. mtg, Honolulu 1959.60, Proc., p. 27. Riggs, H. C., 1960, Discussion of paper by A. L. Sharp, A. E. Gibbs, W. J. Owen, and B. Harris, Application of the multi- ple regression approach in evaluating parameters affecting water yields of river basins: J our GeOphys. Research, v. 65, no. 10, p. 3509—3511. 1961, Frequency of natural events: Am. Soc. Civil Engi- neers Proc., v. 87, no. HYl, p. 15—26, 9 figs. Roberson, C. E., and Whitehead, H. C., 1961, Ammoniated thermal waters of Lake and Colusa Counties, California: U.S. Geol. Survey Water-Supply Paper 1535—A, p. A-1-A-11, 3 figs. LIST OF PUBLICATIONS Roberts, R. J., 1960 Paleozoic structure in the Great Basin [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1955. Robinove, C. J., and Berry, D. W., 1960, Availability of ground water in the Bear River valley, Wyoming, with, a section on The chemical quality of the water, by J. G. Connor: U.S. Geol. Survey open-file report, 78 p., 13 figs. Robinson, C. S., 1960, Origin of Devils Tower, Wyoming [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2040. Robinson, C. S., and Rosholt, J. N., Jr., 1960, Apparent age and migration of uranium in deposits in sandstone based on radiochemical analyses [abs.] 2 Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1957. Robinson, T. W., and Johnson, A. I., 1961, Selected bibliography on evaporation and transpiration: U.S. Geol. Survey open- file report, 52 p. Rodis, H. G., 1961, Availability of ground water in Lyon County, Minnesota: U.S. Geol. Survey Cir. 444, 7 p., 1 fig. Rodis, H. G., and Schneider, Robert, 1960, Occurrence of ground waters of low hardness and of high chloride content in Lyon County, Minnesota: U.S. Geol. Survey Circ. 423, 2 p., 1.fig. Roedder, Edwin, 1960a, Fluid inclusions as samples of the ore- forming fluids: Internat. Geol. Cong., 21st, Copenhagen 1960, pt. 16, sec. 16, Proc., p. 218—229. 1960b, Primary fluid inclusions in sphalerite crystals from the OH vein, Oreede, Colorado [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1958. Rolfe, B. N., Miller, R. F., and McQueen, I. S., 1960, Dispersion characteristics of montmorillonite, kaolinite and illite clays in waters of varying quality, and their control with phos- phate dispersants: U.S. Geol. Survey Prof. Paper 334—G, p. 229—273. Rollo, J. R., 1960, Ground water in Louisiana: Louisiana Dept. Conserv., Dept. Public Works, Water Resources Bull. 1, 84 p., 3 pls., 16 figs. Roman, Irwin, 1960, Apparent resistivity of a single uniform overburden: U.S. Geol. Survey Prof. Paper 365, 99 p., 11 figs. Rora-baugh, M. I.,, 1960a, Problems of waste disposal and ground- water quality: Am. Water Works Assoc. Jour., v. 52, no. 8, p. 979—982. 1960b, Use of water levels in estimating aquifer constants: Internat. Assoc. Sci. Hydrology Pub. 52, p. 314—323, 7 figs. Rose, H. J ., Jr., and Stern, ’1‘. W., 1960a, Spectrochemical deter- mination of lead in zircon for lead-alpha age measurements [abs.] : J our. Geophys. Research, v. 65, no. 8, p. 2520. 1960b, Spectrochemical determination of lead in zircon for lead-alpha age measurements: Am. Mineralogist, v. 45, nos. 11—12,p. 1243—1256. Roseboom, E. H., J r., 1960, High temperature X-ray studies in the system Cu—S [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1959. Rosholt, J. N., Jr., 1960, Radiochemical determination of ap- parent age of uranium migration in sandstone-type ore de- posits [atbs.]: Geol. Soc. America Bull., v. 71, no. 12, pt, 2, p. 1961. 1961, Late Pleistocene and Recent accumulation of urani- um in ground water saturated sandstone deposits: Econ. Geology, v. 56, no. 2, p. 423—430. Rosholt, J. N., Jr., and Dooley, J. R., Jr., 1960, Automatic mea- surements and computations for radi0chemical analyses: Anal. Chemistry, v. 32, no. 8, p. 1093—1098. Rosholt, J. N., Jr., Emiliani, C., Geiss, J., Koczy, F. F., and Wangersky, P. J., 1961, Absolute dating of deep-sea cores by the Pam/Th2” method: Jour. Geology, v. 69, no. 2, p. 162—185. A—175 Ross, C. P., 1959, Geology of Glacier National Park and the Flathead region, northwestern Montana: U.S. Geol. Survey Prof. Paper 296, 125 p., 4 pls., 33 figs. [1960]. 1960, Geomorphology of the southern part of central Idaho [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1962. 1961, Geology of the southern part of the Lemhi Range, Idaho: U.S. Geol. Survey Bull. 1081—F, p. 189—260, pls. 7—10, fig. 14. Ross, C. S., and Smith, R. L., 1961, Ash flow tufts: their origin, geologic relations, and identification: U.S. .Geol. Survey Prof. Paper 366, 81 p., 99 figs. Ross, Malcolm, and Evans, H. T., J r., 1960, The crystal structure of cesium biuranyl trisulfate, CS1(U02)2(SO4)32 J our. Inor- ganic and Nuclear Chemistry, v. 5, p. 338—351. Ross, R. J., Jr., 1961, Distribution of Ordovician graptolites in eugeosynclinal facies in western North America and its paleogeographic implications: Am Assoc. Petroleum Geolo- gists Bull., v. 45, no. 3, p. 330—341. Ross, R. J ., Jr., Palmer, A. R., and Merriam, C. W., 1960, Lower Paleozoic stratigraphic problems in the Great Basin [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1962. Rubin, Myer, 1960, Changes in Wisconsin glacial stage chronol- ogy by 0—14 dating: Am. Geophys. Union Trans, v. 41, no. 2, p. 288—289. Rubin, Meyer, and Berthold, S. M., 1961, U.S. Geological Survey radiocarbon dates VI, in Radiocarbon: New Haven, Conn., Am. Jour. Sci., v. 3, p. 86—98. Ruiz, C. F., Aguirre, Luis, Corvalan, José, Rose, H. J ., Jr., Segerstrom, Kenneth, and Stern, T. W., 1960, Stratigraphic setting of Chilean intrusions, their lead-alpha age, and the relation of orogeny to intrusive activity [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1963. Ruiz, Carlos, Segerstrom, Kenneth, Aguirre, Luis, Corvalan, Jose, Rose, H. J., Jr., and Stern, T. W., 1960, Edades plomo- alfa y marco estratigrafico de granites chilenos, Con una discusion acerca de su relacion con la orogenesis: Chilea Inst. Inv. Geol. B01. no. 7, 26 p., 1 fig., 1 table. Russell, R. H., 1960, Artificial recharge of a well at Walla Walla : Am. \Vater Works Assoc, Jour. v. 52, no. 11, p. 1427—1437. Sable, E. G., and Dutro, J. T., Jr., 1961, New Devonian and Mississippian formations in De Long Mountains, northern Alaska: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 5, p. 585—593. Sainsbury, C. L., 1960, Metallization and hypogene post-mineral argillization, Lost River tin mine, Alaska: Econ. Geology, v. 55, no. 7, p. 1478—1506. Saint-Amand, Pierre, 1960, Chilean earthquakes of 1960 [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2110. Sample, R. D., and Albee, H. F., 1961a, Claim map, Anderson Mesa quadrangle, Montrose and San Miguel Counties, Colo- rado: U.S. Geol. Survey open-file report. 1961b, Claim map, Atkinson Creek quadrangle, Montrose County, Colorado: U.S. Geol. Survey open-file report. 1961c, Claim map, Bull Canyon quadrangle, Montrose and San Miguel Counties, Colorado: U.S. Geol. Survey open- file report. 1961d, Claim map, Calamity Mesa quadrangle, Mesa County, Colorado: U.S. Geol. Survey open-file report. 1961e, Claim map, Davis Mesa quadrangle, Montrose County, Colorado: U.S. Geol. Survey open-file report. 1961f, Claim map, Egnar quadrangle, San Miguel County, Colorado: U.S. Geol. Survey open-file report. A—176 Sample, R. D., and Albee, H. F., 1961g, Claim map, Gateway quadrangle, Mesa County, Colorado: US. Geol. Survey open-file report. 1961b, Claim map, Gypsum Gap quadrangle, San Miguel County, Colorado: US. Geol. Survey open-file report. 1961i, Claim map, Joe Davis Hill quadrangle, San Miguel County, Colorado: US. Geol. Survey open-file report. 1961j, Claim map, Juanita Arch quadrangle, Mesa County, Colorado: U.S. Geol. Survey open-file report. 1961k, Claim map, Naturita NW qaudrangle, Montrose and San Miguel Counties, Colorado: US. Geol. Survey open-file report. 19611, Claim map, Paradox quadrangle, Montrose County, Colorado: US. Geol. Survey open-file report. 1961m, Claim map, Pine Mountain quadrangle, Mesa County, Colorado: US. Geol. Survey open-file report. 1961n, Claim map, Red Canyon quadrangle, Montrose, County, Colorado: U.S. Geol. Survey open-file report. 19610, Claim map, .Roc Creek quadrangle, Montrose County, Colorado: US. Geol. Survey open-file report. 1961p, Claim map, Uravan quadrangle, Montrose County, Colorado: U. S. Geol. Survey open-file report. Sample, R. D., Albee, H. F., and Stephens, H. G., 1961a, Claim map, Bull Canyon quadrangle, Montrose County, Colorado (revised) : U.S. Geol. Survey open-file report. 1961b, Claim map, Hamm Canyon quadrangle, San Miguel County, Colorado: U.S. Geol. Survey open-file report. 1961c, Claim map, Horse Range Mesa quadrangle, San Miguel County, Colorado: US. Geol. Survey open-file report. Sandberg, C. A., 1961a, Description of cores of Middle Devonian and uppermost Silurian rocks in Mobil Producing Com- pany’s No. 1 Birdbear well, Dunn County, North Dakota, in North Dakota Geol. Soc., Stratigraphy of the Williston basin—Devonian system : p. 45—47. 1961b, Possible Early Devonian seaway in northern Rocky Mountain area [abs] : Am. Assoc. Petroleum Geolo- gists Bull., v. 45, no. 3, p. 416. Sando, W. J ., 1960, Corals from well cores of Madison group, Williston basin: U. S. Geol. Survey Bull. 1071-F, p. 157—190, pls. 13—20, figs. 16—17 [1961]. 1961, Morphology and ontogeny of Ankhelasma, a new Mississippian coral genus: Jour. Paleontology, v. 35, no. 1, p. 65—81. Sando, W. J ., and Dutro, J. T., J r., 1960, Stratigraphy and coral zonation of the Madison group and Brazer dolomite in northeastern Utah, western Wyoming and southwestern Montana, in Overthrust belt of southwestern Wyoming and adjacent areas, Wyoming Geol. Assoc. Guidebook 15th Ann. Field Conf., 1961 : p. 117—126. Sanford, T. H., J r., and West, L. R., 1960, Use of step-drawdown tests to predict yields of wells [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2024—2025. Schaller, W. T., and Vlisidis, A. C., 1961, The composition of the aluminian ludwigite from Crestmore, California: Am. Mineralogist, v. 46, no’s. 3—4, pts. 1—2, p. 335—339. Schiner, G. R., 1960, Ground-water exploration and test pumping in the Halma-Lake Bronson area, Kittson County, Min- nesota: U.S. Geol. Survey open-file report, 70 p., 11 figs. Schlocker, Julius, 1960, Geologic features of the Franciscan formation of significance in engineering [abs] : California Assoc. Eng. Geologists, 3d ann. mtg., Berkeley, Calif., Oc- tober 1960, Program, p. 12. Schmidt, D. L., 1960, Pliocene silicic ignimbrites and basalt flows in the Bellevue quadrangle, Idaho [abs] : Geol. Soc. Amer- ica Bull., v. 71, no. 12, pt. 2, p. 2074. GEOLOGICAL SURVEY RESEARCH 1961—~SYNOPSIS OF RESULTS Schmidt, R. G., Pecora, W. T. Bryant, Bruce, and Ernst, W. G., 1961, Geology of the Lloyd quadrangle, Bearpaw Mountains, Blaine County, Montana: US. Geol. Survey Bull. 1081—E, p. 159—188, pl. 6. Schnabel, R. W., 1960, Bedrock geology of the Avon quadrangle, Connecticut: US Geol. Survey Geol. Quad. Map GQ—134. Schneider, Robert, 1961, Correlation of ground-water levels and air temperatures in the winter and spring in Minnesota : U.S. Geol. Survey Water-Supply Paper 1539—D, p. D-l—D-14, 6 figs. Schneider, W. J ., and Ayer, G. R., 1961, Eflect of reforestation 0n streamflow in central New York: US. Geol. Survey Water- Supply Paper 1602, 61 p., 34 figs. Scholl, D. W., 1960, Pleistocene algal pinnacles at Searles Lake, California: Jour. Sed. Petrology, v. 30, no. 3, p. 414—431. Schopf, J. M., 1960, Field description and sampling of coal beds: U.S. Geol. Survey Bull. 1111—B, p. 25—70, pls. 6-27, fig. 3 [1961]. Schopf, J. M., and Long, W. E., 1960, Antarctic coal geology [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1967. Schultz, L. G., 1960, Quantitative X-ray determinations of some aluminous clay minerals in rocks: Natl. Conf. Clays and Clay Minerals, 7th, Washington, D.C., 1958, Proc., p. 216— 224. Schultz, L. G., Tourtelot, H. A., and Gill, J. R., 1960, Mineralogy of the Pierre shale (Upper Cretaceous) in South Dakota and adjacent areas [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2041. Schumm, S. A., 1960a, The effect of sediment type on the shape and stratification of some modern fluvial deposits: Am. Jour. Sci., v. 258, no. 3, p. 177—189, 1 p1., 2 figs. 1960b, The shape of alluvial channels in relation to sediment type: U.S. Geol. Survey Prof. Paper 352—B, p. 17—30, pl. 5, figs. 8—16. 1961, Efiect of sediment characteristics on erosion and deposition in ephemeral-stream channels: U.S. Geol. Sur- vey Prof. Paper 352—0, p. 31—70, figs. 17—41. Schumm, S. A., and Hadley, R. F., 1961, Progress in the ap- plication of landform analysis in studies of semiarid ero- sion : U.S. Geol. Survey Circ. 437, 14 p., 9 figs. Scott, G. R., 1960a, Surficial geology of the KaSSler and Little- ton quadrangles near Denver, Colorado, in Geol. Soc. Amer- ica, jointly with Rocky Mtn. Assoc. Geologists and Colorado Sci. Soc., Guide to the geology of Colorado: p. 204—206. 1960b, Quaternary sequence east of the Front Range near Denver, Colorado, in Geol. Soc. America, jointly with Rocky Mtn. Assoc. Geologists and Colorado Sci. Soc., Guide to the geology of Colorado: p. 206—211. 1960c, Subdivision of the Quaternary alluvium east of the Front Range near Denver, Colorado: Geol. Soc. Amer- ica Bull., v. 71, no. 10, p. 1541—1544. Scott, R. A., 1960, Pollen of Ephcdm from the Chinle formation (Upper Triassic) and the genus Equisetosporites: Micro- paleontology, v. 6, no. 3, p. 271—276. Seaber, P. R., 1960, Hydrochemical facies and ground-water flow patterns in the Englishtown sand in the coastal plain of New Jersey [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1971. Searcy, J. K., 1960, Graphical correlation of gaging-station records, Manual of hydrology, part l—General surface- water techniques: U.S. Geol. Survey Water-Supply Paper 1541—0, p. 67—100, pl. 1, figs. 9—14. LIST OF PUBLICATIONS Searcy, J. K., and Davis, L. C., J r., 1961, Time of travel of Water in the Potomac River, Cumberland to Washington: U.S. Geol. Survey Circ. 438. Segerstrom, Kenneth, 1960a, Erosion and related phenomena at Paricutin in 1957: U.S. Geol. Survey Bull. 1104—A, p. 1—18, pl. 1, figs. 1—10. 1960b, Eruption of water, sand, and clay resulting from the earthquake of May 21, 1960, near Concepcién, Chile [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1972. ——~—— 1960c, Structural geology of an area east of Copiapo, Atacama Province, Chile: Internat. Geol. Cong, 21st, Copen- hagen 1960, pt. 18, sec. 18, Proc., p. 14—20. 1960a, Descripcion de la geologia de la region del Rio Copiapo comprendida entre la Fundicion de Paipote y el Tranque Lautaro: Minerales (Inst. Ingenieros de Minas de Chile), v. 15, no. 71, p. 24—28. 1960e, Carta geolégica de Chile: Cuadrangulo Llampos, Provincia de Atacama: Chile Inst. Inv. Geol., v. 2, no. 2, 40 p. 1960f, Carta geologica de Chile : Cuadrangulo Chamorate, Provincia de Atacama: Chile Inst. Inv. Geol., v. 2, no. 3, 40 p. Senftle, F. E., Pankey, Titus, and Grant, F. A., 1960, Magnetic susceptibility of tetragonal titanium dioxide: Phys. Rev., v. 120, no. 3, p. 820—825. Senftle, F. E., and Thorpe, Arthur, 1961, Magnetic susceptibility of normal liver and transplantable hepatoma tissue: Na- ture, v. 190, no. 4774, p. 410—413. Shacklette, H. T., 1961, Substrate relationships of some bryo- phyte communities on Latouche Island, Alaka: Bryologist, v. 64, no. 1, p. 1—6. Shaw, C. E., J r., and Petersen, R. G., 1960, Ground-water condi- tions in the Mattapoisett River basin, Massachusetts, Ap- pendix A in Sterling, C. 1., Jr., Special report on ground water resources in the Mattapoisett River Valley: Mas- sachusetts Water Resources Comm. Bull. \V.R. 1, p. 9—25. Shawe, F. R., Reeves, R. G., and Kral, V. E., 1961, Iron ore deposits of northern Nevada: U.S. Geol. Survey open-file report, 83 p., 10 figs., 8 tables. Sherwood, C. B., and Klein, Howard, 1960, Water-table contour map, Dade County, Florida: U.S. Geol. Survey open-file report. Shoemaker, E. M., 1960, Penetration mechanics of high velocity meteorites illustrated by Meteor Crater, Arizona: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 18, sec. 18, Proc., p. 418—434. Shoemaker, E. M., and Chao, E. C. T., 1960, Origin of the Ries basin, Bavaria, Germany [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2111. Shoemaker, E. M., and Hackman, R. J ., 1960, Stratigraphic basis for a lunar time scale [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2112. Sigafoos, R. S., and Hendricks, E. L., 1961, Botanical evidence of the modern history of Nisqually Glacier, Washington: U.S. Geol. Survey Prof. Paper 387-A, p. A-1—A-20, 15 figs. Silberling, N. J ., 1960, Mesozoic stratigraphy of the Great Basin [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1973. 1961, Upper Triassic marine mollusks from the Natchez Pass formation in northwestern Nevada: Jour. Paleon- tology, v. 35, no. 3, p. 535—542. Simmons, E. T., Grosman, I. G., and Heath, R. C., 1961, Ground- water resources of Dutchess County, New York: New York Water Resources Comm. Bull. GW—43, 82 p., 3 pls., 5 figs. A—177 Simmons, G. C., 1960, Origin of certain cangas of the “Quad- rilatero Ferrifero” of Minas Gerais, Brazil: Soc. Brasiliera Geol. Bol., v.9, no. 2, 59 p. Simons, D. B., Richardson, E. V., and Albertson, M. L., 1961, Flume studies using medium sand (0.45 mm) : U.S. Geol. Survey Water-Supply Paper 1498—A, p. A—l—A—76, 28 figs. Simons, F. S., 1961, Geologic map and sections of the Klondyke quadrangle, Arizona: U.S. Geol. Survey open-file report. Simpson, E. S., 1960, Summary of current geological research in the United States of America pertinent to radioactive- waste disposal on land, in International Atomic Energy Agency, Disposal of radioactive wastes: Sci. Conf. Disposal Radioactive Wastes, Principality Monaco, Nov. 16—21, 1959, Proc., v. 2, p. 517—531. Simpson, H. E., 1960, Geology of the Yankton area, South Dakota and Nebraska: U.S. Geol. Survey Prof. Paper 328, 124 p., 13 pls., 11 figs. [1961]. Simpson, T. A., 1960, Structural interpretations in the Birming- ham red iron ore district, Alabama [abs] : Geol. Soc. Amer- ica Bull., v. 71, no. 12, pt. 2, p. 2025. Sims, P. K., 1960a, Geology of the Central City-Idaho Springs area, Front Range, Colorado, in Geol. Soc. America, jointly with Rocky Mtn. Assoc. Geologists and Colorado Sci. Soc., Guide to the geology of Colorado: p. 279—285. 1960b, Hypogene mineral zoning, Central City district, Colorado [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1974. Siple, G. E., 1960a, Piezometric levels in the Cretaceous sand aquifer of the Savannah River basin: Georgia Mineral Newsletter, v. 13, no. 4, p. 163—166, 1 fig. 1960b, Some geologic and hydrologic factors affecting limestone terranes of Tertiary age in South Carolina: Southeastern Geology, v. 2, no. 1, p. 1—11, 2 figs. Sisco, H. G., 1960, Records of wells and water-level fluctuations in the Aberdeen-Springfield area, Bingham and Power Counties, Idaho, in 1959: U.S. Geol. Survey open-file report, 37 p., 1 p1., 4 figs. Sisler, F. D., 1960, Geomicrobiological effect on hydrogen-isotope equilibria in the marine environment [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1974. 1961, Geomicrobiology of Antarctica, in Science in Alaska, pt. 1—The life sciences in Antarctica: Natl. Acad. Sci.- Natl. Research Council Pub. 839. p. 147—150. Skibitzke, H. E., 1960a, Electronic computers as an aid to the analysis of hydrologic problems : Internat. Assoc. Sci. Hydro- logy Pub. 52, Gen. Assembly, Helsinki 1960, p. 347—358, 5 figs. 1960b, Electronics and ground water: Arizona Sewage and Water Works Assoc. Official Bull. 1960, v. 20, no. 1, p.104—110. 1960c, Radioisotopes in the laboratory for studying ground-water motion: Internat. Assoc. Sci. Hydrology Pub. 52, Gen. Assembly, Helsinki 1960, p. 513—523, 7 figs. Skibitzke, H. E., Chapman, H. T., Robinson, G. M., and McCul- lough, R. A., 1961, Radio—tracer techniques for the study of flow in saturated porous materials: Jour. Appl. Radia- tion and Isotopes, v. 10, no. 1, p. 38—46. Skinner, B. J ., 1960, Assemblage enargite-famatinite, a possible geologic thermometer [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1975. Skipp, B. A. L., 1961, Interpretation of sedimentary features in Brazer limestone (Mississippian) near Mackay, Custer County, Idaho: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 3, p. 376—389. A—178 Skougstad, M. W., and Barker, F. B., 1960, Occurrence and behavior of natural and radioactive strontium in water: Public Works, v. 91, no. 7, p. 88—90, 3 figs. Smedes, H. W., 19603, Mesozoic thrust faults in the northern Wallowa Mountains, Oregon [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1977. 1960b, Monzonite ring dikes along the margin of the Antelope Creek stock, Montana [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1977. Smith, G. I., 1960, Estimate of total displacement on the Garlock fault, southeastern California [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1979. Smith, R. L., 1960a, Zones and zonal variations in welded ash flows: U.S. Geol. Survey Prof. Paper 354-F, p. 149—159, pls. 20—21 [1961]. ‘ 1960b, Ash flows: Geol. Soc. America Bull., v. 71, p. 795— 842. Smith, R. L., Bailey, R. A., and Ross, C. S., 1960, Calderas— aspects of their structural evolution and their relation to ring complexes [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1981. Sniegocki, R. T., 1960, Ground-water recharge and conserva- tion—effects of temperature and viscosity: Am. Water Works Assoc. Jour., v. 52, no. 12, p. 1487—1490, 3 figs. Sohl, N. F., 1960, Archeogastropoda, Mesogastropoda, and stratigraphy of the Ripley, Owl Creek, and Prairie Bluff formations: U.S. Geol. Survey Prof. Paper 331—A, p. 1—151, pls. 1—18, flgs. 1—11 [1961]. Sohn, I. G., 1960a, Cleaning ostracode valves with ultrasonic vibrations [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1982. 1960b, Palezoic species of Bairdia and related genera: U.S. Geol. Survey Prof. Paper 330—A, p. 1—105, pls. 1—6, figs. 1—15 [1961]. 1960c, Terrestrial ostracodes: Science, v. 132, no. 3423, p. 366, 368. Soister, P. E., 1960, Landslide debris from Cretaceous rocks in the Wind River formation of early Eocene age, Wind River Basin, Wyoming [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1982—1983. Soward, K. S., 1960, Geology of damsites on the upper tributaries of the Columbia River in Idaho and Montana—Knowles and Perma damsites, lower Flathead River, Sanders County, Montana: U.S. Geol. Survey open-file report. Speer, P. B., 1960, Lowest mean discharge and flow duration data by years at selected gaging stations in the Mississippi Embayment area: U.S. Geol. Survey open-file report, 666 p. 3 figs. Staatz, M. H., and Carr, W. J ., 1961, Geologic map of the Thomas and Dugway Ranges,.. Juab and Tooele Counties, Utah: U.S. Geol. Survey open-file report. Stafford, P. T., 1960, Stratigraphy of the Wichita group in part of the Brazos River valley, North Texas: U.S. Geol. Survey Bull. 1081—G, p. 261—280, pls. 11—~12, fig. 15 [1961]. Stallman, R. W., 1960, Notes on the use of temperature data for computing ground-water velocity: U.S. Geol. Survey open- file report, 17 p. ' 1961,. From geologic data to aquifer analog models: Geo- times, v. 5, no. 7, p. 8—11, 37. Starkey, H. C., 1960, Aspects of ion exchange in zeolites [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1984. Steacy, R. E., 1961, Time of travel of water in the Ohio River, Pittsburgh to Cincinnati: U.S. Geol. Survey Circ. 439. GEOLOGICAL SURVEY RESEARCH 1 9 6 l—SY'NOPSIS OF RESULTS Stephens, J. W., 1960, Barometric effect on water levels: Little Rock, Arkansas, Gazette, July 24, 1960, p. GE, 2 figs. Steven, T. A., 1960, Geology and fluorspar deposits, Northgate district, Colorado: U.S. Geol. Survey Bull. 1082—F, p. 323— 422, pls. 12—17, figs. 33—41 [1961]. Steven, T. A., and Ratté, J. C., 1960, Geology and ore deposits of the Summitville district, San Juan Mountains, Colorado: U.S. Geol. Survey Prof. Paper 343, 70 p., 9 pls., 15 figs. Stevens, P. R., 1960, Ground-water problems in the vicinity of Moscow, Latah County, Idaho: U.S. Geol. Survey Water- Supply Paper 1460—H, p. 325—357, pl. 13, figs. 25—32 Stewart, D. B., 1960a, Effect of LiAlSiO. and SiO:. on the separa- tion of the 131 and 131 X—ray-diffraction lines of synthetic albite [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1985. 1960b, The system LiAlsiOrNa-AlsiaOerO at 2,000 bars: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 17, sec. 17, Proc., p. 15—30. Stewart, J. H., 1961, Stratigraphy and origin of the ChinJe formation (Upper Triassic) of the Colorado Plateau: U.S. Geol. Survey open-file report, 196 p., 48 figs., 2 tables. Stewart, J. H., McKnight, E. T., Bush, A. L., Litsey, L. R., and Sumsion C. T., 1960, Log S9—Cortez to Whitewater, via Telluride and Naturita, via U.S. 160, Colorado 145, and Colorado 141, in Rocky Mtn. Assoc. Geologists, Geological road logs of Colorado : p. 17—35. Stewart, J. H., and Wilson, R. F., 1960, Triassic strata of the salt anticline reg-ion, Utah and Colorado, in Geology of the Paradox Basin fold and fault belt, Four Corners Geol. Soc. Guidebook, 3d Field Conf., 1960: p. 98—106. Stewart, J. W., 1960, Relation of salty ground water to fresh artesian water in the Brunswick area, Glynn County, Georgia: Georgia Geol. Survey Inf. Circ. 20, 42 p., 6 figs. Stewart, J. W., and Croft, M. G., 1960, Ground-water with- drawals and decline of artesian pressures in the coastal counties of Georgia: Georgia Geol. Survey Mineral News- letter, v. 13, no. 2, p. 84—93, 7 figs. Stieff, L. R., and Stern, T. W., 1961, Graphic and algebraic solutions of the discordant lead—uranium age problem: Geo— chim. et Cosmochim. Acta, v. 22, nos. 2—4, p. 176—199. Stoimenoff, L. E., 1960, Floods of May 1959 in the Au Gres and Rifle River basins, Michigan: U.S. Geol. Survey open-file report, 14 p., 6 figs. Straczek, J. A., Horen, Arthur, Ross, Malcolm, and Warshaw, C. M., 1960, Studies of the manganese oxides. IV. Todorokite: Am. Mineralogist, v. 45, nos. 11—12, p. 1174—1184. Swartz, J. H., and Raspet, B., 1961, Thermal shock and its effect on thermistor drift: Nature, v. 190, no. 4779, p. 875— 878. Swenson, F. A., 1960, Ground-water phenomena associated with the Hebgen Lake, Montana, earthquake of August 17, 1959 [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2041— 2042. Switzer, George, and Reichen, L. E., 1960, Reexamination of pilinite and its identification with bavenite: Am. Mineral- ogist, v. 45, nos. 7—8, p. 757—762. Tatlock, D. B., Wallace, R. E., and Silberling, N. J., 1960, Alkali metasomatism Humboldt Range, Nevada [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2079—2080. Taylor, D. W., 1960, Late Cenozoic molluscan faunas from the High Plains: U.S. Geol. Survey Prof. Paper 337, 94 p., 4 pls., 2 figs. LIST OF‘ PUBLICATIONS Taylor, D. W., 1961, The freshwater clam Pisidium ultramo’m tanum Prime in Modoc County, California: Veliger, v. 3, p. 111. Taylor, G. 0., Jr., and Pathak, B. D., 1960, Geology and ground- water resources of the Anjar-Khedoi region, eastern Kutch (India) : India Geol. Survey Bull. 9, ser. B, 339 p., 9 pls., 9flgs. Taylor, G. H., 1960a, Recharging ground-water reservoirs: U.S. Geol. Survey open-file report, 31 p., 1 fig. 1960b, Springs—their origin, development, and protec- tion: U.S. Geol. Survey open-file report, 15 p., 1 fig. Teichert, Curt, and Kummel, Bernhard, 1960, Size of endoceroid cephalopods: Harvard Univ. Mus. Comp. Zoology Breviora, no. 128, p. 1—7. Terriere, R. T., 1960, Geology of the Grosvenor quadrangle, Brown and Coleman Counties, Texas: U.S. Geol. Survey Bull. 1096—A, p. 1—35,p1s. 1—3, figs. 1—6. Thayer, T. P., 1960, Some critical differences between alpine- type and stratiform peridotite-gabbro complexes: Inter- nat. Geol. Cong, 21st, Copenhagen 1960, pt. 13, sec. 13, Proc., p. 247—259. Theobald, P. K., Jr., and Havens, R. G., 1960, Base metals in biotite, magnetite, and their alteration products in a hydro- thermally altered quartz monzonite porphyry sill, Summit County, Colorado [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1991. Thomas, D. M., 1961, Extent and frequency of inundation of flood plain in vicinity of Somerville and Manville, New Jersey: U.S. Geol. Survey open-file report, 24 p., 8 figs. Thomas, H. D., Love, J. D., and McGrew, P. 0., 1961, Relation- ship of latest Cretaceous and Tertiary deformation to oil and gas occurrences in Wyoming [abs] : Am. Assoc. Petro- leum Geologists Bull., v. 45, no. 3, p. 415. Thomas, H. E., 1961, Ground water and the law: U.S. Geol. Sur- vey Circ. 446, 6 p. Thomasson, H. G., Jr., Olmsted, F. H., and LeRoux, E. F., 1960, Geology, water resources, and usable ground-water stor- age capacity of part of Solano County, California: U.S. Geol. Survey Water-Supply Paper 1464, 693 p., 23 pls., 30 figs. Todd, Ruth, 1960, Some observations on the distribution of Calcam‘m and Baculogypsmo in the Pacific: Tohoku Univ. Sci. Repts., ser. 2 (Geology), Spec. v. 4 (Prof. Shoshiro Hanzawa Mem. VOL), p. 100—108, pl. 10, fig. 1, tables 1—2. Todd, Ruth, and Low, Doris, 1960, Smaller Foraminifera from Eniwetok drill holes: U.S. Geol. Survey Prof. Paper 260—X, p. 799—861, pls. 255—264, figs. 256—259. 1961, Near-shore Foraminifera of Martha’s Vineyard Is- land, Massachusetts: Cushman Found. Foram. Research Contr., v. 12, pt. 1, p. 5—21. Toulmin, Priestley, 3d, 1960a, Composition of feldspars and crystallization history of the granite-syenite complex near Salem, Essex County, Massachusetts: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 13, sec. 13, Proc., p. 275—286. 1960b, Effect of Cu on sphalerite phase equilibria—a preliminary report [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1993. 1961, Geologic significance of lead-alpha and isotopic age determinations of “alkalic” rocks of New England: Geol. Soc. America Bull., v. 72, no. 5, p. 775-780. Tourtelot, H. A., 1961, Thin sections of clay and shale: Jour. ‘ Sed. Petrology, v. 31, no. 1, p. 131—132. A—l79 Tourtelot, H. A., and Schultz, L. -G., 1961, Core from the Irish Creek well, Ziebach County, South Dakota: U.S. Geol. Survey open-file report, 20 p., 2 figs. Tracey, J . 1., Jr., 1961, Relations of reefs to water circulation [abs.] : Am. Assoc. Petroleum Geologists, Rocky Mtn. Sec., and Soc. Econ. Paleontologists and Mineralogists, 46th ann. mtg, Denver, 0010., April 24—27, 1961, Program, p. 35. Tracey, J. I., J r., Abbott, D. P., and Arnow, Ted, 1961, Natural history of Ifaluk Atoll—physical environment: Bernice P. Bishop Mus. Bull. 222, 75 p. Trainer, F. W., 1960, Geology and ground-water resources of the Matanuska Valley agricultural area, Alaska: U.S. Geol. Survey Water-Supply Paper 1494, 116 p., 8 figs, 3 pls., 5 tables. 1961, Eolian deposits of the Matanuska Valley agricul- tural area, Alaska: U.S. Geol. Survey Bull. 1121—0, p. 01—0-35, 6 figs. Trauger, F. D., 1960, Availability of ground water at proposed well sites in Gila National Forest, Sierra and Catron Counties, New Mexico: New Mexico State Engineer Tech. Rept. 18, 20 p., 3 pls., 2 figs. Trexler, J. P., 1960, Geologic mapping with aerial photographs in the anthracite region of eastern Pennsylvania [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2026—2027. Trumbull, James, 1959, Coal fields of the United States, sheet 1 : U.S. Geol. Survey [1960]. Tschanz, C. M., 1960, Geology of northern Lincoln County, Nevada, in Guidebook to the geology of east central Nevada, Intermountain Assoc. Petroleum Geologists and Eastern Nevada Geol. Soc. 11th Ann. Field Conf., 1960: p. 198—208. Tschanz, C. M., and Pampeyan, E. H., 1960, Geologic map of Lincoln County, Nevada [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2080. Tuttle, C. R., Koteff, Carl, and Hartshorn, J. H., 1960, Seismic investigations in the Connecticut River Valley, southern Massachusetts [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1994. Tweto, Ogden, 1960, Scheelite in the Precambrian gneisses of Colorado: Econ. Geology, v. 55, no. 7, p. 1406—1428. Tweto, Odgen, and Sims, P. K., 1960, Precambrian ancestry of the Colorado mineral belt [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1995. U.S. Geological Survey, 1960a, Compilation of records of sur— face waters of the United States through September 1950, part 1—B——North Atlantic slope basins, New York to York Rivers: U.S. Geol. Survey Water-Supply Paper 1302, 679 p., 1 pl., 2 figs. 1960b, Compilation of records of surface waters of the United States through September 1950, part 2—B—South Atlantic slope and eastern Gulf of Mexico basins, Ogeechee River to Pearl River: U.S. Geol. Survey Water-Supply Paper 1304, 399 p., 1 pl., 2 figs. 1960c, Complilation of records of surface waters of the United States through September 1950, part 10—The Great Basin: U.S. Geol. Survey Water-Supply Paper 1314, 485 p., 1 pl., 3 figs. 1960d, Compilation of records of surface waters of the United States through September 1950, part 11—A—-Pacific slope basins in California except Central Valley: U.S. Geol. Survey Water-Supply Paper 1315—B, p. 461—874,vp1. 2, figs. 8—10. 1960c, Floods near Chicago Heights, Illinois: U.S. Geo]. Survey Hydro]. Inv. Atlas HA—39 [1961]. A—180 US. Geological Survey, 1960f, Geological Survey Research 1960—Synopsis of geologic results: U.S. Geol. Survey Prof. Paper 400—A, p. A1—A136, 4 figs. 1960g, Geological Survey Research 1960—Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400B, p. B1—B515, 310 figs. 1960h, Ground-water levels in the United States, North- eastern States, 1956—57: US Geol. Survey Water-Supply Paper 1537, 144 p., 13 figs. 1960i, Quality of surface waters for irrigation, Western United States, 1957: US. Geol. Survey Water-Supply Paper 1524, 183p, 1 p1. 1960j, Quality of surface waters of the United States, 1956, parts 5 and 6—Hudson Bay and upper Mississippi River basins, and Missouri River basin: U.S. Geol Survey Water-Supply Paper 1451, 349 p., 1 fig. 1960k, Quality of surface waters of the United States, 1956, parts 9—14—Colorado River basin to Pacific slope basins in Oregon and lower Columbia River basin: U.S. Geol. Survey Water-Supply Paper 1453, 447 p., 1 fig. 1957, parts 1—4——North Atlantic slope basins to St. Lawrence River basin: U.S. Geol. Survey Water-Supply Paper 1520, 641 p., 1 fig. 1960m, Quantity and quality of surface waters of Alaska, 1958: US. Geol. Survey Water-Supply Paper 1570, 120 p. 1960n, Surface water supply of Hawaii 1956—58: US. Geol. Survey Water-Supply Paper 1569, 295 p. 19600, Surface water supply of the United States, 1958, part 1—B—Nor-t-h-Atlantic slope basins, New York to York River: U.S. Geol. Survey Water-Supply Paper 1552, 563 p., 2 figs. // 1960p, Surface water supply of the United States, 1958, part 5—Hudson Bay and upper Mississippi River basins: U.S. Geol. Survey Waiter-Supply Paper 1558, 638 p., 2 figs. 1960a, Surface water supply of the United States, 1959, part 2—A—South Atlantic slope basins, James River to Sa- vannah River: U.S. Geol. Survey Water-Supply Paper 1623, 269 p., 2 figs. 1960r, Surface water supply of the United States, 1959, part 1—A—North Atlantic slope basins, Maine to Connecti- cut: U.S. Geol. Survey Water-Supply Paper 1621, 276 p., 2 figs. 1960s, Surface water supply of the United States, 1959, part 2—B—South Atlantic slope and eastern Gulf of Mexico basins, Ogeechee River to Pearl River: U.S. Geol. Survey Water-Supply Paper 1624, 488 p., 2 figs. [1961]. 1960t, Surface water supply of the United States, 1959, part 3—A—Ohio River basin except Cumberland and Tennes- see River basins: U.S. Geol. Survey Water-Supply Paper 1625, 565 p., 2 figs. [1961]. 1960u, Surface water supply of the United States, 1959, part 3—B—Cumber1and and Tennessee River basins: U.S. Geol. Survey Walter-Supply Paper 1626, 242 p., 2 figs. 1960v, Surface water supply of the United States, 1959, part 4—St. Lawrence River basin: U.S. Geol. Survey Water- Supply Paper 1627, 417 p., 2 figs. [1961]. 1960w, Surface water supply of the United States, 1959, part 6—A—Missouri River basin above Sioux City, Iowa: US. Geol. Survey Water-Supply Paper 1629, 415 p., 2 figs. 1960):, Surface water supply of the United States, 1959, part 6—B—Missouri River basin below Sioux City, Iowa: US. Geol. Survey Water-Supply Paper 1630, 474 p., 2 figs. 19601, Quality of surface waters of the United States. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS US. Geological Survey, 1960y, Surface water supply of the United States, 1959, part 7—Lower Mississippi River basin: U.S. Geol. Survey Water-Supply Paper 1631, 559 p., 2 figs. [1961]. 1960z, Surface water supply of the United States, 1959, part 8—Western Gulf of Mexico basins: U.S. Geol. Survey Water-Supply Paper 1632, 529 p., 2 figs. [1961]. 1960aa, Surface water supply of the United States, 1959, part 9—Colorado River basin: U.S. Geol. Survey Water- Supply Paper 1633, 506 p., 3 figs. ’ 1960bb, Surface water supply of the United States, 1959, part 10—The Great Basin : U.S. Geol. Survey Water-Supply Paper 1634, 247 p., 2 figs. 1960ee, Surface water supply of the United States, 1959, part ll—Pacific slope basins in California: US. Geol. Sur- vey Water-Supply Paper 1635, 748 p., 2 figs. [1961]. 1960dd, Surface water supply of the United States, 1959, part 12—Pacific slope basins in Washington and upper Columbia River basin: U.S. Geol. Survey Water-Supply Paper 1636, 402 p., 2 figs. 1960ee, Surface water supply of the United States, 1959, part 13—Snake River basin: U.S. Geol. Survey Water- Supply Paper 1637, 271 p., 2 figs. 1960113, Surface water supply of the United States, 1959, part 14—Pacific slope basins in Oregon and lower Columbia River basin: U.S. Geol. Survey Water-Supply Paper 1638, 300 p., 2 figs. 1961a, Quality of surface waters of the United States 1957, parts 7—8—Lower Mississippi River basin and Gulf of Mexico: U.S. Geol. Survey Water-Supply Paper 1522. 1961b, Surface water supply of the United States 1959, part 1—B—North Atlantic slope basins, New York to York River: U.S. ,Geol. Survey Water-Supply Paper 1622. 1961c, Surface water supply of the United States, 1959, part 5—Hudson Bay and upper Mississippi River basins: U.S. Geol. Survey Water-Supply Paper 1628, 562 p., 2 figs. 1961d, Surface water supply of the United States, 1959, part 1—B—North Atlantic slope basins, New York to York River: U.S. Geol. Survey Water—Supply Paper 1622, 537 p., 2 figs. 1961e, Surface water supply of Hawaii, 1958-59: US. Geol. Survey Water-Supply Paper 1639, 149p. 1961f, Quantity and quality of surface waters of Alaska, 1959: US. Geol. Survey Water-Supply Paper 1640, 114 p. 1961g, Floods at Mount Vernon, Ohio: US. Geol. Survey Hydrol. Inv. Atlas PIA—40. Upson, J. E., and Spencer, C. W., 1960, Glacial geology of buried bedrock valleys of the New England coast [abs] : Geol. Soc. America Bu11., v. 71, no. 12, pt. 2, p. 1995. van Hylckama, T.E.A., 1960, Measuring water use by saltcedar: Arizona Land Dept. Watershed Symposium Proc., 4th ann., Arizona 1960, p. 22—26. Vaudrey, W. C., 1960, Floods of May 1955 in Colorado and New Mexico: U.S. Geol. Survey Water-Supply Paper 1455—A, p. 1—68, pls. 1—4, figs. 1—12. Vine, J. D., 1960, Recent domal structures in southeastern New Mexico: Am. Assoc. Petroleum Geologists Bull., v. 44, no. 12, p. 1903—1911. Visher, F. N., 1960, Qualitative hydrodynamics within an oceanic island: Internat. Assoc. Sci. Hydrology Pub. 52, p. 470—477. Visher, F. N., and Mink, J. F., 1960, Summary of preliminary findings in ground-water studies in southern Oahu, Hawaii : U.S. Geol. Survey Circ. 435, 16 p., 14 figs. LIST OF PUBLICATIONS Voegeli, P. T., Sr., and Hershey, L. A., 1960, Records and logs of selected wells and test holes, and chemical and radiometric analyses of ground water, Prowers County, Colorado: Colorado Water Conserv. Board, Ground Water Ser. Basic Data Rept. 1, 52 p., 1 p1., 1 fig. Waage, K. M., 1961, Stratigraphy and refractory clayrocks of the Dakota group along the northern Front Range, Colo— rado: U.S. Geol. Survey Bull. 1102, 154 p., 8 pl., 13 figs. Wait, R. L., 1960a, Summary of the ground-water resources of Clay County, Georgia: Georgia Geol. Survey Mineral News- letter, v. 13, no. 2, p. 93-101, 4 figs. 1960b, Summary of the ground-water resources of Terrell County, Georgia: Georgia Geol. Survey Mineral Newsletter, v. 13, no. 3, p. 117—122, 2 figs. Waldron, H. H., 1961a, Geology of the Des Moines quadrangle, Washington: U.S. Geol. Survey open-file report. 1961b, Geology of the Poverty Bay quadrangle, Wash- ington : U.S. Geol. Survey open-file report. Waller, R. M., 1960, Water utilization in the Anchorage area, Alaska, 1958—59: U.S. Geol. Survey open—file report, 43 p., 7 figs. Walters, K. L., 1960, Availability of ground water at the Border Stations at Laurier and Ferry, Washington: U.S. Geol. Survey Cir. 422, 8 p., 4 figs. 1961, Geology and ground-water resources of Sumner County, Kansas: Kansas Geol. Survey Bull. 151. Walters, K. L., and Grolier, M. J ., 1960, Geology and ground— water resources of the Columbia Basin Project area, Wash- ington: Washington Water—Supply Bull. 8, 542 p., 3 pls., 25 figs. Walton, W. C., and Scudder, G. D.,1960, Ground-water resources of the valley-train deposits in the Fairborn area, Ohio: Ohio Dept. Nat. Resources, Div. Water_ Tech. Rept. 3, 57 p., 3 pls., 26 figs. Ward, F. N., 1961, Camp— and sample-site determination of traces of mercury in soils and rocks: Am. Inst. Mining, Metall. Petroleum Engineers Trans, v. 217, p. 343—350. Ward, P. E., 1960, Relation of mineral springs to Permian salt [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1999. 1961, Salt springs in Oklahoma: Oklahoma Geology Notes, v.21, no. 3, p. 82—85, 4 figs. ' Warren, W. 0., 1959, Reconnaissance geology of the Birney- Broadus coal field, Rosebud and Powder River Counties, Montana: U.S. Geol. Survey Bull. 1072-J, p. 561—585, pls. 19—26, figs. 22—23 [1960]. Watkins, F. A., Jr., and Rosenshein, J. S., 1960, Ground—water geology and hydrology of Bunker Hill Air Force Base, Peru, Indiana: U.S. Geol. Survey open-file report, 76 p. Wayland, R. G., 1961, Tofty tin belt, Manley Hot Springs dis- trict, Alaska: U.S. Geol. Survey Bull. 1058-I, p. 363—414, pls. 40—43, fig. 48. Weaver, Mary A., and Radbruch, I). H., 1960, Selected logs of borings on the east side of San Francisco Bay, California: U .S. Geol. Survey open-file report, 465 p. Weber, F. R., and Péwé, T. L., 1960, Reconnaissance engineering geology for highway location in Alaska [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2088. \Vedow, Helmuth, Jr., 1960, Sequatchie and Rockwood forma- tions in southeast Tennessee and part of northwest Georgia [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2028. Weeks, E. P., 1960, Hydrologic conditions in the Horseshoe Creek Valley near Glendo, Platte County, Wyoming: U.S. Geol. Survey open-file report, 10 p., 3 figs. 608400 0—61—13 A—181 Weir, G. W., Carter, W. D., Puffett, W. P., and Gualtieri, J. L., 1960, Preliminary geologic map and section of the Mount Peale 4 NE quadrangle, San Juan County, Utah, and Mon- trose and San Miguel Counties, Colorado: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—150 [1961]. Weir, G. W., Dodson, C. L., and Puffett, W. P., 1960, Preliminary geologic map and section of the Mount Peale 2 SE quad- rangle, San Juan County Utah: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—143. Weir, G. W., and Puffett, W. P., 1960a, Preliminary geologic map and sections of the Mount Peale 2 NE quadrangle, San Juan County, Utah: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—141 [1961]. 1960b, Preliminary geologic map of the Mount Peale 4 SE quadrangle, San Juan County, Utah, and the San Miguel County, Colorado: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—149 [1961]. 1960c, Similarities of uranium-vanadium and copper de- posits in the Lisbon Valley area, Utah-Colorado: Internat. Geol. Cong, 21st, Copenhagen 1960, pt. 15, sec. 15, Proc., p. 133—148. Weir, G. W., Puffett, W. P., and Dodson, C. L., 1961, Preliminary geologic map and section of the Mount Peale 4 NW quad- rangle, San Juan County, Utah: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—151. Weist, W. G., J r., 1960, Records and logs of selected wells and test holes, and chemical analyses of ground Water, Yuma County, Colorado: Colorado Water Conserv. Board, Ground Water Ser. Basic Data Rept. 2, 41 p., 1 p1., 1 fig. Wells, J. D., 1960, Stratigraphy and structure of the House Rock Valley area, Coconino County, Arizona: U.S. Geol. Survey Bull. 1081—D, p. 117—158, pls. 4—5, figs. 11—12 [1961]. Wells, J. D., Sheridan, D. M., and Albee, A. L., 1960, Equiva- lence of the Precambrian Idaho Springs formation and the quartzite along Coal Creek, Front Range, Colorado [abs.] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2000. West, S. W., 1961, Availability of ground water in the Gallup area, New Mexico: U.S. Geol. Survey Circ. 443, 21 p., 1 pl., 2 figs. White, G. W., 1960, Classification of Wisconsin glacial deposits in northeastern Ohio: U.S. Geol. Survey Bull. 1121—A, p. A-l—A-12, 1 fig. Wiesnet, D. R., 1961, Composition, grain size, roundness, and sphericity of the Potsdam sandstone in northeastern New York: Jour. Sed. Petrology, v. 31, no. 1, p. 5—14. Wilcox, R. E., 1960, Optic-angle determination on the spindle stage [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2003. Willden, Ronald, 1960a, Geology of the Jackson Mountains, Humboldt County, Nevada: U.S. Geol. Survey open-file report, 120 p., 34 figs., 4 tables. 1960b, Major westward thrusting of post-Middle Triassic age in northwestern Nevada [abs.] : Geol. Soc. America Bull., no. 12, pt. 2, p. 2003—2004. 1961, Preliminary geologic map of Humboldt County, Nevada: U.S. Geol. Survey Mineral Inv. Field Studies Map RIF—236. Willden, Ronald, and Mabey, D. R., 1961, Giant dessication fis- sures on the Black Rock and Smoke Creek Deserts, Nevada : Science, v. 133, no. 3461, p. 1359—1360. A—182 GEOLOGICAL Wilmarth, V. R., Healey, D. L., Clebsch, Alfred, J r., Winograd, I. J., Zietz, Isidore, and Oliver H. W., 1960, A summary interpretation of geologic, hydrologic, and geophysical data for Yucca Valley, Nevada Test Site, Nye County, Nevada: U.S. Geol. Survey TEI—358, open—file report, 51 p., 5 figs, 6 tables. , Winslow, J. D., 1960, Hydrogeology of the Middle Branch Valley near Canton, Ohio [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2005. Witkind, I. J., 1960, The Hebgen Lake, Montana, earthquake of August 17, 1959, in Billings Geol. Soc. Guidebook 11th Ann. Field Conf., Sept. 7—10, 1960: p. 31—44. Witkind, I. J., Hemphill, W. R., Pillmore, C. L., and Morris, R. H., 1960, Isopach mapping by photogeologic methods as an aid in the location of swales and channels in the Monument Valley area, Arizona: U.S. Geol. Survey Bull. 1043—D, p. 57—85, pls. 3—5, figs. 18—27. Wolcott, D. E., and Gott, G. B., 1960, Stratigraphy of the Inyan Kara group in the southern Black Hills, South Dakota and Wyoming [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2043. Wones, D. R., 1960, Hydrogen as a component in biotite phase equilibria [abs] : Geol. Soc. America Bull., V. 71, no. 12, pt. 2, p. 2006. Wood, G. H., J r., and Kehn, T. M., 1961, Sweet Arrow fault, east- central Pennsylvania: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 2, p. 256—263. Wood, P. R., 1960, Geology and ground-water features of the Butte Valley region, Siskiyou County, California: U.S. Geol. Survey \Vater-Supply Paper 1491, 150 p., 3 pls., 7 figs. [1961]. \Voodard, T. H., and Thomas, J. D., 1960, Chemical and physical character of surface waters of North Carolina, 1957—58: North Carolina Dept. IVater Resources Bull. 1, v. 2, 191 p. Woodland, M. V., 1960, Data of rock analyses—VII. Bibliography and index of rock analyses in the periodical and serial litera- ture of the Republic of Ireland and of Northern Ireland: Geochim. et Cosmochim. Acta, v. 20, no. 2, p. 149—153. Woodring, ‘V. P., 1960, Oligocene and Miocene in the Caribbean region: Caribbean Geol. Conf., 2d, Puerto Rico 1959, Trans, p. 27—32 [1961]. Woodring, W. P., and Malavassi V., Enrique, 1961, Miocene Foraminifera, mollusks and a barnacle from the Valle Central, Costa Rica: Jour. Paleontology, v. 35, no. 3, p. 489—497. Wyrick, G. G.,‘ 1960a, Geochemical Inethods for defining ground- water flow [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2029. 1960b, Ground-water resources of Volusia County, Flor- ida: Florida Geol. Survey Rept. Inv. 22, 65 p., 30 figs. Yates, R. G., 1961, Geology of part of the Boundary and Spirit quadrangles, Stevens County, Washington: U.S. Geol. Sur- vey open-file report. Yates, R. G., and Ford, A. E., 1960, Preliminary geologic map of the Deep Lake quadrangle, Stevens and Pend Oreille Counties, Washington: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—237. SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Yerkes, R. F., 1960, Preliminary geologic maps of the La Habra and Whittier quadrangles, Los Angeles Basin, California: U.S. Geol. Survey open-file report. Yochelson, E. L., 1960a, Gastropods, in Boucot, A. J., and others, A late Silurian fauna from the Sutherland River formation, Devon Island, Canadian Arctic Archipelago: Canada Geol. Survey Bull. 65, p. 41—47. 1960b, Permian Gastropoda of the southwestern United States, Part 3—Bellerophontacea and Patellacea: Am. Mus. Nat. History Bull., v. 119, art. 4, p. 205—294. 1960c, Status of paleontology [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2116. 1961a, Note on the class Coniconchia: J our. Paleontology, v. 35, no. 1, p. 162—167. 1961b, Notes on the operculum, mode of life, and clas- sification of Hyolithves: Jour. Paleontology, v. 35, no. 1, p. 152—161. Yochelson, E. L., Cheney, T. M., Van Sickle, Dianne, and Dunkle, D. H., 1961, Permian outcrops in western Duchesne County, Utah: Am. Assoc. Petroleum Geologists Bull., v. 45, no. 1, p. 107—108. Young, E. J., and Powers, H. A., 1960, Chevkinite in volcanic ' ash : Am. Mineralogist, v. 45, nos. 7—8, p. 875—881. Young, E. J., and Sims, P. K., 1961, Petrography and origin of xenotime and monazite concentrations, Central City district, Colorado: U.S. Geol. Survey Bull. 1032—F, p. 273—299, figs. 66—73. Young, R. A., 1960, Ground-water areas and well logs, central Sevier Valley, Utah: U.S. Geol. Survey open-file report, 33 p., 1 fig. Young, R. A., and Carpenter, C. H., 1961, Developing ground water in the central Sevier Valley, Utah: Salt Lake City, Utah State Engineer’s Office, 6 p., 1 fig. Zadnik, V. E., 1960, Petrography of the Upper Cambrian d010- mites of Warren County, New Jersey: U.S. Geol. Survey open-file report, 96 p., 18 figs, 27 pls., 1 table. Zen, E-an, 1960a, Petrology of lower Paleozoic rocks from the slate belt of western Vermont: Internat. Geol. Cong, 21st, Copenhagen 1980, pt. 13, sec. 13, Proc., p. 362—371. 1960b, Time and space relationships of the Taconic rocks in western Vermont and eastern New York [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2009. 1961, The zeolite facies: an interpretation: Am. Jour. Sci., v. 259, no. 6, p. 401-409. ‘ Zietz, Isidore, 1961, Remanent magnetization and aeromagnetic interpretation [abs] : Soc. Explor. Geophysicists Yearbook 1961, p. 235. Zimmerman, E. A., 1960, Preliminary report on the geology and ground-water resources of northeastern Blaine County, Montana: Montana Bur. Mines and Geology Bull. 19, 19 p., 1 pl., 5 figs. Zimmerman, Richard, and Yochelson, E. L., 1961, The Cambrian gastropod Claudia buttsi in Missouri: Jour. Paleontology, v. 35, no. 1, p. 229—230. Zubovic, Peter, ShefEey, N. B., and Stadnichenko, Taisia, 1960, Geochemical associations of certain minor elements in coal [abs] : Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 2009. GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS A—183 INDEX TO LIST 0]? PUBLICATIONS Alabama, geology, Birmingham district : Simpson, T. A., 1960 Alaska: Aeromagnetic investigations, Cook Inlet: Grantz, Zietz, and Andreasen, 1960 Copper River Basin: Andreasen and others, 1960 Kobuk, Minchumina, Cape Espenberg, Cape Lisburne, Brooks Range areas : Andreasen, 1960b Yukon Flats-Kandik area : Andreasen, 1960a Coal, Matanuska field: Barnes, F. F., 1960 Coalfields, map: Barnes, F. F., 1961 Engineering geology, highway location: Weber and Péwé, 1960 Geologic map, Admiralty Island: Lathram, Loney, Berg, and Pomeroy, 1960 Brooks Range: Brosgé, Reiser, Patton. and Mangus, 1960; Brosgé, Dutro, Mangus, and Reiser, 1960 Hagemeister Island quadrangle: Hoare and Coonrad, 1961 Katalla area : Kachadoorian, 1960b; Miller, 1961a Lituya district: Miller, 1961b Malaspina district : Miller, 1961c Nenana-Rex area : Kachadoorian, 1960a Wiseman quadrangle: Brosgé and Reiser, 1960 Yakataga district: Miller, 1961d Yakutat district: Miller, 1961e Geology, Cape Thompson: Kachadoorian, Lachenbruch, Moore, and Waller, 1960; Kachadoorian and others, 1961 Copper River basin : Andreasen and others, 1960 eastern Chugach Mountains: Brabb and Miller, 1960 Lower Kuskokwim-Bristol Bay region : Hoare, 1961 Matanuska Valley: Trainer, 1960, 1961 near Nome: Hummel, 1960 Shaviovik-Sagavanirktok Rivers region: Keller, A. 8., Morris, and Detterman, 1961 southeastern : Lathram, 1960 Tofty tin belt : Wayland, 1961 Geothermal investigations, Ogotoruk Creek: Lachenbruch, Greene, and Marshall, 1960 Glaciation, Yukon-Tanana upland: Péwé and Burbank, 1960 Gravity investigations, interior Alaska: Barnes, Allen, and Bennett, 1960 Ground water, Fairbanks area : Cederstrom, 1961 Matanuska Valley: Trainer, 1960 Jet drilling, Fairbanks area: C‘ederstrom and Tibbits, 1961 Lost River tin mine: Sainsbury, 1960 Paleontology, ammonites : Imlay, 1960b, 1961 pelecypods : Jones and Gryc, 1960 Seabee formation: Cobban and Gryc, 1961 Petrology, Aleutian Islands volcanic suites : Byers, 1961 Plant ecology, Latouche Island: Shacklette, 1961 Project Chariot: Kachadoorian and others, 1961: Kacha- doorian, Lachenbruch, Moore, and Waller, 1960; Lachenbruch, Greene, and Marshall, 1960 Stratigraphy, Devonian and Mississippian, De Long Moun- tains: Sable and Dutro, 1961 Nome coastal plain: Hopkins, MacNeil, and Leopold, 1960 Alaska—Continued Structure and tectonic history: Gates, G. 0., and Gryc, 1961 'lVater utilization, Anchorage : Waller, 1960 Antarctic: Coal, geology: Schopf and Long, 1960 Geodesy and cartography : Lyddan, 1961 Geologic research : Davies, 1961 Geologic fieldwork : Hamilton, 1960d Geology: Craddock and Hubbard, 19614 Geomicrobiology: Sisler, 1961 Glacial history, McMurdo Sound : Péwé, 1960a—c Tectonics: Hamilton, 1961 Atlantic Coastal Plain, ground water: Bach, 1960b, c Arizona : Crustal structure : Diment, Stewart, and Roller, 1961 Evaporation, effect of Salt River reservoirs: Koberg, 1960 Geologic map, Emmett Wash NW quadrangle: Petersen and Wells, 1960 Haunted Canyon quadrangle: Peterson, D. W., 1960 Klondyke quadrangle: Simons, F. S., 1961 Paria Plateau SE quadrangle: Petersen, 1961 Final Ranch quadrangle: Peterson, N. P., 1961 San Pedro and Aravaipa Valleys: Creasey, Jackson, and Gulbrandsen, 1961 Geology, House Rock Valley area: Wells, 1960 McMullen Valley : Kam, 1961 Monument Valley : VVitkind, Helnphill, Pillmore, and Morris, 1960 Near Superior and Globe: Peterson, D. W., 1961 Geophysical investigations, Twin Buttes : Keller, Plouff, and Zietz, 1960 ' Ground water, 1959—60; Hardt, Stulik, and Booker, 1960 Coconino standstone, Snowflake-Hay Hollow area: Johnson, P. W., 1960 Painted Rock damsite: Cahill, 1960 McMullen Valley : Kam, 1961 Wupatki and Sunset Crater Cosner, 1960 Hydrologic data, Papago Indian Reservation: Heindl and Cosner, 1960 Meteor Crater: Chao, 1960b; Shoemaker, 1960 Water use, Cottonwood Wash: Hendricks, Kam, and Bowie, 1960 National Monuments : Arkansas: Bauxite: Emmett, 1960 Coal resources, 1954: Haley, 1960 Geologic history: Cordova, 1960 ; Hosman, 1960a, 1961 Geomorphology: Plebuch, 1960 Ground water : Edds, 1960, 1961 ; Hosman, 1960b Mineralogy, Magnet Cove: Milton, Charles, Ingram, and Blade, 1960 Pinnacle Mountain : Albin, 1960 Artesian wells, effect of trains on levels: Bearden, 1960a, b Basin and Range province, geophysical investigations: Mabey, Pakiser, and Kane, 1060 Bibliography : Biochemical factors : Oborn, 1960a Conodonts : Ash, 1961a A—l84 Bibliography—Continued Evaporation and transpiration: Robinson, ’1‘. W., and John- son, 1961 Geochemical abstracts: Markward, 1961 Geophysical abstracts : Clarke, Vitaliano, Neuschel, and others, 1960a—c, 1961a, b North American geology 1958: King, R. R., and others, 1961 Rock analyses: Woodland, 1960 Slope evolution: Hopkins, D. M., and Wahrhaftig, 1960 Specific yield : Johnson, A. 1., Morris, and Prill, 1960 Bolivia, landslide, La Paz: Dobrovolny, 1960 Botanical prospecting: Cannon, E. L., 1961a, b; Froelich and (Kleinhampl, 1960; Kleinhampl and Kotefl, 1960 Brazil, geology, Quadrilatero Ferrifero: Simmons, G. C., 1960 California: Algal pinnacles, Searles Lake: Scholl, 1960 Chemical composition, Aqua de Ney spring: Feth, Rogers, and Roberson, 1961 Core logs, Mojave area: Benda, Erd, and Smith, 1960 San Francisco Bay: Weaver and Radbruch, 1960 Franciscan formation, engineering factors : Schlocker, 1960 Example of eugeosynclinal deposition : Bailey, 1960a Geologic map, Baldwin Hills area: Castle, 1960a Barstow quadrangle: Dibblee, 1960a Beverley Hills and Venice quadrangles: Castle, 1960b Bouquet Reservoir quadrangle: Dibblee, 1961a La Habra and Whittier quadrangles: Yerkes, 1960 Lancaster quadrangle: Dibblee, 1960b Lane Mountain quadrangle: McCulloh, 1960 Geology, Alvord Mountain quadrangle: Byers, 1960 Butte Valley region : Wood, P. R., 1960 Central Valley: Repenning, 1961 Edwards Air Force Base: Dutcher and Worts, 1960 Garlock fault: Smith, G. I., 1960 Independence dike swarm : Moore, J. G., and Hopson, 1961 Kern River : MacKevett, 1960 Kramer quadrangle: Dibblee, 1961b Northern Coast Ranges: Irwin, 1960 Rogers Lake quadrangle: Dibblee, 1961b San Joaquin Valley: Lofgren, 1960a—c Shasta Valley: Mack, 1960 Solano County : Thomasson, Olmstead, and LeRoux, 1960 Geomorphology, alluvial fans, Fresno County: Bull, 1960a, b; 1961a, b San Joaquin Basin : Matthes, 1960 Geophysical investigations, Owens Valley: Kane and Pakiser, 1961 Glacial geology, San Joaquin Basin: Matthes, 1960 Gravity surveys, volcanic areas: Pakiser, 1960 Ground water, Butte Valley region: Wood, P. R., 1960 Edwards Air Force Base: Dutcher, 1960; Dutcher and Hiltzen, 1960; Dutcher and Worts, 1960; Moyle, 1960 Middle Mojave area: Page, R. W., and Moyle, 1960 Napa and Sonoma Valleys: Kunkel and Upon, 1960 Point Arguello: Evenson, 1961 Point Mugu: Page, R. W., 1961 San Joaquin Valley: Poland, 1960b Shasta Valley: Mack, 1960 Solano County: Thomasson, Olmstead, and LeRouX, 1960 Twentynine Palms: Dyer, 1961 GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS California—Continued Iron deposits: Lamey, 1961 Land subsidence, San Joaquin Valley: Poland, 1960b Mineralogy, jadeite, New Idria district: Coleman, 1961 Paleontology, fresh water clam: Taylor, D. W., 1961 Mojave Desert: Lewis, 1960 Stream and spring flow, Tecolote Tunnel area: Rantz, 1961a Stream waters, geologic control of mineral composition: Davis, G. H., 1961 Thermal waters, Lake and Colusa Counties: Roberson and Whitehead, 1961 Uranium deposits, Kern River area: MacKevett, 1960 Water resources, 1959, southern: Peterson, W. C., 1960 Water well data, Kern County: Kunkel and Dutcher, 1960 Santa Barbara County: Muir, Merritt, and Miller, 1960 California, Gulf of, origin : Hamilton, 1960e Canada: Geophysical investigations, Athabasca glacier: Keller, G. V., and Frischknecht, 1960 Paleontology, Devon Island : Yochelson, 1960a Sudbury lopolith : Hamil-ton, 1960a Caribbean region : Pumice and pozzolan deposits: Eckel, 1960b Stratigraphy : Woodring, 1960 Chemistry: Analytical techniques: Dinnin, 1960a, b; Dinnin and Kinser, 1961; Fletcher, 1960a, b; Haffty, 1960; Horr, Myers, and Dunton, 1961; May, I., 1961; Myers, A. T., Havens, and Dunton, 1961; Myers, A. T. and Wood, 1960; Rainwater and Thatcher, 1960; Rose and Stern, 1960 a, b; Rosholt and Dooley, 1960 Chile: Copper deposits: Carter, 1960 Earthquakes 1960: Saint-Amand, 1960; Segerstrom, 1960b Geology: Ruiz, Segerstrom, Aguirre, Corvalan, Rose, and Stern, 1960; Segerstrom 1960c—f Clay minerals, dispersion characteristics: Rolfe, Miller, and McQueen, 1960 Colorado: Claim maps: Sample and Albee, 1961a—p; Sample, Albee, and Stephens, 1961a—c Dike swarms, West Spainish Peak-Dike Mountain area: Johnson, R. B., 1961 Earth flow near Lake City: Crandell and Varnes, 1960 FlOod frequency : Jenkins, 1960b Flood of May 1955 : Vaudrey, 1960 Fluorspar deposits, Northgate district: Steven, 1960 Geochemistry, Creede ore minerals: Bethke, Barton, and Bodine, 1960; Roedder, 1960b Geologic map, igneous and metamorphic rocks: wether, 1960a Mount Peale 4 NE quadrangle: Weir, Carter, Puffett, and Gualtieri, 1960 Mount Peale 4 SE quadrangle: Weir and Puflett, 1960b Willow Creek Butte quadrangle: Hansen, 1961b Geology, Central City-Idaho Springs area: Harrison and Moench, 1961 ; Sims, 1960 Cortez to Whitewater: Stewart, McKnight, Bush, Lit- sey, and Sumsion,1960 Front Range foothills: Lewis, 1960 Kassler and Littleton quadrangles: Scott, 1960a Little Cone quadrangle: Bush, Marsh, and Taylor, 1960 Lower Mesozoic rocks: Oriel and Craig, 1960 Mineral belt: Tweto and Sims, 1960 Mere- INDEX TO LIST OF PUBLICATIONS Colorado—Continued Geology—Continued Northgate district: Steven, 1960 Pennsylvanian and Permian: Maughan and Wilson, 1960 Piceance Creek basin : Donnell, 1961 Platte Canyon and Kassler quadrangles: W. L., and Scott, 1960 Poncha Springs to Montrose: Olson and Hedlund, 1960 Quaternary, near Denver: Scott, 1960 Raton Mesa region: Johnson, R. B., 1960 Rocky Mountain National Park : Richmond, 1960 Sangre de Cristo Mountains: Johnson, R. B., Baltz, 1960 Summitville district: Steven and Ratté, 1960 Tenmile Range: Koschmann, 1960 Glaciation, east slope, Rocky Mountain National Park: Richmond, 1960 Ground water, Huerfano County: McLaughlin, Burtis, and Wilson, 1961 Ogallala formation : Moulder, 1960b Prowers County : Voegeli and Hershey, 1960 Yuma County 2 Weist, 1960 Mineral deposits, Lisbon Valley area: Weir and Puffett, 1960c Scheelite in Precambrian gneisses : Tweto, 1960 Summitville district: Steven and Ratté, 1960' Mineral paragenesis, Tenmile Range: Koschmann, 1960 Mineral zoning, Central City district: Sims, 1960b Mineralogy, Green River formation: Milton, Charles, Chao, Fahey, and Mrose, 1960 Oil shale resources, Piceance Creek basin : Donnell, 1961 Paleontology, vertebrate, Front Range foothills: Lewis, 1960 Petrology, Central City district: Young, E. J ., and Sims, 1961 Summit County: Theobald and Havens, 1960 Salt anticlines, development: Cater and Elston, 1961 early growth: Elston, 1960 Stratigraphy, Dakota group: Waage, 1961 Hermosa formation: Hite, 1960 Idaho Springs formation: Wells, Sheridan, and Albee, 1960 near Denver: Scott, G. R., 1960 Pennsylvanian: Mallory, 1960 Raton Mesa ‘coal region: Johnson, R. B., and Roberts, Peterson, and 1960 Triassic, salt anticline region: Stewart and Wilson, 1960 Structural history, Uncompahgre front: Elston and Shoe- maker, 1960 Uranium deposits, map: Merewether, 1960a Uranium-vanadium deposits, Rifle Creek area : Fischer, 1960 Colorado Plateau : Botanical prospecting for uranium: Cannon, H. L., 1960b Grain-size distribution, sedimentary rocks: Cadigan, 1961 Stratigraphy, Chinle formation: Stewart, J. H., 1961 Temperature in sediments: Breger and Chandler, 1960 Uranium deposits, chemical composition guide to size: Miesch, Shoemaker, Newman, and Finch, 1960 statistical studies: Miesch and Riley, 1960, 1961 See also Arizona, Colorado, New Mexico, and Utah A—185 Connecticut: Geology, Avon quadrangle: Schnabel, 1960 southeastern : Goldsmith, 1960a Uncasville quadrangle: Goldsmith, 1960b Windsor Locks quadrangle: Colton, 1960 Ground—water map, Oneco quadrangle: Johnson, K. E., Mason, and DeLuca, 1960 Voluntown quadrangle: Randall, Hahn, 1960 Water resources, quality : Pauszek, 1960 Cordilleran foreland, techtonic problems in: Osterwald, 1961 Costa Rica, paleontology : Woodring and Malavassi, 1961 Crystal chemistry : Andalusite, kyanite, and sillimanite: Clark, S. P., Skinner, and Appleman, 1960 Bikitaite : ’Appleman, 1960 Cesium biuranyl trisulfate: Ross, Malcolm, and Evans, 1960 Clinoenstatite and pigeonite: Morimoto, Appleman, and Evans, 1960 Fairfleldite: Mrose and Appleman, 1960 CEB305(OH) : Clark and Christ, 1960b Doloresite: Evans and Mrose, 1960 Haggite: Evans and Mrose, 1960 Larderellite: Clark, 1960 Metavanadates: Evans, 1960 Meyerhofierite: Clark and Christ, 1960a; Christ and Clark, 1960b Reedmergnerite: Clark and Appleman, 1960a, b Uranyle oxide hydrates : Christ and Clark, 1960a Veatchite: Clark and Mrose, 1960 Delaware: Mineral deposits: Pearre and Heyl, 1960 Water resources, artificial recharge, Newark 2 Groot, 1960 Sussex County: Rasmussen, Wilkens, and Beall, 1960 Earth scientists, opportunities and responsibilities : Eckel, 1960a Earthquake, Hebgen Lake: Fraser, 1960; Hadley, 1960a; Myers, W. B.,1960 Extraterrestrial studies: Analysis: Adler, 1960c Coesite and space geology: Pecora, 1960 Floods: J anuary-February 1959, Indiana: Hale and Hoggatt 1961 Near Chicago: U.S. Geol. Survey, 1960e New England to North Carolina, 1955: Bogart, 1960 Southeastern states, 1961: Barnes, H. H., and Somers, 1961 Florida : Bucatunna clay, relation to geology and ground water: Marsh, 1960b Geology, Martin County : Lichtler, 1960 Ground water, Dade County: Sherwood and Klein, 1960 Fernandina area : Leve, 1961 Martin County: Lichtler, 1960 Volusia County: Wyrick, 1960b Westernmost: Marsh, 1960b Hydrology, Green Swamp area: Pride, Meyer, and Cherry, 1961 Water, flow pattern in Biscayne aquifer: Kohout, 1960a, b Fuels: Coal, Alaska: Barnes, F. F., 1960, 1961 Antarctic: Schopf and Long, 1960 Arkansas, 1954: Haley, 1960 Field description and sampling: Schopf, 1960 Geochemistry : Breger, 1961 Bierschenk, and A—186 Fuels—Continued United States: Trumbull, 1959 Wyoming: Mapel, 1959 Petroleum and natural gas, Wyoming: Thomas, H. D., Love, and McGrew, 1961 Geochemical field investigations : Idaho, Coeur d’Alene district: Kennedy, 1960a North Carolina, Concord quadrangle: Bell, H., and Over- street, 1960; Overstreet and Bell, 1960a Geochemical fleld techniques : Copper: Huff, Lovering, Lakin, and Myers, 1960 Mercury : Ward, F. N ., 1961 Geochemistry : Aragonitic mud, microtexture: Hathaway and Robertson, 1960 Biotite phase equilibria : Wones, 1960 Copper-sulfur: Roseboom, 1960 Distribution of elements: Chao and Fleischer, 1960; Fleischer and Chao, 1960; Gulbrandsen, 1960a; Herz and Dutra, 1960; Miesch, Shoemaker, New— man, and Finch, 1960; Myers, A. T., and Hamilton, 1960 Enargite—famatinite: Skinner, 1960 Fluid inclusion: Roedder, 1960a, b “Fulgurite,” analysis: Carron and Lowman, 1961 Nephelite group: Stewart, D. B., 1960a, b Organic: Breger, 1960, 1961; Breger and Chandler, 1960; Breger, Tourtelot, and Chandler, 1960; Pommer and Breger, 1960a, b; Zubovic, Sheffey, and Stad- nickenko, 1960 Quartz solubility: Fournier, 1960 / / Research at Kilauea: Ault, 1960 f ’/ Sphalerite phase equilibria : Toulmin, 1960b Statistical measures, Colorado Plateau uranium ores: Miesch and Riley, 1960, 1961 Sulfide deposits: Barton, Toulmin, and Sims, 1960; Love- ring,1961 Volcanic materials : Murata, 1960 Water: Back, 1960a-c, 1961; Brown, P. M., and Floyd, 1960; Durum and Haft'ty, 1961; Feth, 1960; Feth, Rogers, and Roberson, 1961; Hem, 1960, 1961a, b; Hembree and Rainwater, 1961; Mink, 1960b; Oborn, 1960a, b; Oborn and Hem, 1961; Skougstad and Barker, 1960 Geochronology : Bergelle Massif: Griinenfelder and Stern, 1960 Chilean intrusions: Ruiz, Aguirre, Corvalan, Rose, Seger¢ strom, and Stern, 1960 Claypool site, northeastern Colorado : Malde, 1960 Climatic changes since last interglacial: Flint and Brandt- ner, 1961 Deep sea cores: Rosholt, Emiliani, Geiss, Koczy, and Wangersky, 1961 Discordant lead-uranium ages: Stieft and Stern, 1961 Early man, Moab, Utah: Hunt, 1960a Europe: Faul, 1961 .‘ Maine: Faul. 1961 j _ New England alkalic rocks : Toulmin, 19617 Obsidian method: Friedman, I., and Smith, 1961 Radiocarbon dates: Rubin and Berthold, 1961 Saudi Arabia : Aldrich and Brown, 1960 Southern States : Faul, 1961 Wisconsin glacial stage : Rubin, 1960 Geologic age classification : Cohee, 1960 GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Geologic illustration techniques: Phoenix and Stacy, 1960 Geologic mapping: By interpretation of aerial photographs: Ray, R. G., 1960; Trexler, 1960; Witkind, Hemphill, Pillmore, and Morris, 1960 Contour interpolator: Marsh, 1960a Geologic thermometry: Skinner, 1960 Geological Survey research : U.S. Geol. Survey, 1960f, g Geomorphology : Alluvial fans, Fresno County, California : Bull, 1960a, b; 1961a, b Caves : Moore, G. W., 1960b Craters, origin : Shoemaker, 1960; Shoemaker and Chao, 1960 Desiccation fissures, Nevada: Willden and Mabey, 1961 Erosion, loess: Ray, L. L., 1960 Paricutin : Segerstrom, 1960b Semiarid region : Schumm and Hadley, 1961 Mountain region, central Appalachians : Hack and Goodlett, 1960 Reef structures: Doan, 1960 River meanders: Leopold and Wolman, 1960 Stream channels : Bagnold, 1960; Fahnestock, 1960a, b; Schumm, 1960a, b; 1961 Talus and scree, northern Virginia: Hack, 1960 Terminology: LeGrand, 1960b Geophysical field investigations : Alaska : Andreasen, 1960a, b; Andreasen, Grantz, and Zietz, 1960; Barnes, Allen, and Bennett, 1960 Arizona, Twin Buttes: Diment, Stewart, and Roller, 1961; Keller, Plouff, and Zietz, 1960 Athabasca Glacier : Keller, G. V., and Frischknecht, 1960 Basin and Range province: Mabey, Pakiser, and Kane, 1960 California : Kane and Pakiser, 1961; Pakiser, 1960 Idaho : Hill and Jacobson, 1961 ; Pakiser, 1960 Kentucky: Johnson, R. W., 1960b Massachusetts: Tuttle, Koteff, and Hartshorn, 1960 Nevada : Bunker, 1961 ; Diment, Stewart, and Roller, 1961 New Mexico: Andreasen, Kane, and Zietz, 1961 Tennessee: Johnson, R. W., 1961 Utah: Cook, 1960 Wisconsin: Allingham and Bates, 1960 Electrical logging : Hosman, 1960c Electrical resistivity, interpretation : Roman, 1960 Electromagnetic model studies: Frischknecht and Mangan. 1960 Geophysical methods: Gamma ray logging: Bell and others, 1961 Infrared detection : Barnett and Moxham, 1961 .’ Magnetization, remanent, and aeromagnetic interpretation: Zietz, 1961 Methods in multiaquifer wells : Bennett and Patten, 1960 Thermistor: Swartz and Raspet, 1961 Georgia : Artesian pressures, coastal countries: Stewart, J. W., and Croft, 1960 Savannah area: Odom, 1961 Artesian water—salt water, Brunswick area 2 Stewart, J. W., 1960 Geology, Nuclear Laboratory site: Bowen, Edgerton, Mohr- backer, and Callahan, 1960 Ground-water, Clay County: Wait, 1960a Savannah River basin : Siple, 1960a Terrell County : Wait, 1960b INDEX TO LIST Georgia—Continued Resources: Callahan, 1960 Hydrogeology, limestone terrane: Vaux, 1960 Paleontology, Foraminifera : Herrick, S. M., 1960 Stratigraphy, Sequatchie and Rockwood formations: Wed- ow, 1960 Germany, Ries basin, origin : Shoemaker and Chao, 1960 Great Basin: Geology: Roberts, 1960 Stratigraphy, Lower Paleozoic: Ross, R. J., Palmer, and Merriam, 1960 Mesozoic : Silberling, 1960 Greenland, solution caves: Davies and Krinsley, 1960 Hawaii: Geology, Kauai: Macdonald, Davis, and Cox, 1960 Ground water, Kauai : Macdonald, Davis, and Cox, 1960 Southern Oahu: Visher and Mink, 1960 Kilauea, 1959—60 activity: Ault, 1960; Ault, Eaton, and Richter, 1961 Petrology, Kaupulehu flow : Richter and Murata, 1960 Rainfall, Oahu : Mink, 1960a Silicified wood : Okamura and Forbes, 1961 Tsunami of May 23, 1960: Eaton, Richter, and Ault, 1961; Murata, 1961 High Plains, paleontology : Taylor, D. W., 1960 Hydrodynamics, oceanic island: Visher, 1960 Hydrology: Electronic computer use: Skibitzke, 1960a, b Experimental: Kindsvater, 1961; Leopold, Bagnold, Wol- man, and Brush, 1960; Simons, D. B., Richardson, and Albertson, 1961; Skibitzke, 1960c; Skibitzke, Chamean, Robinson, and McCullough, 1961; Stall- man,1961 Flood-frequency analysis, flood-flow techniques: Dalrymple, 1960 Humid region: Benson/1960 Flood-frequency relations, Pacific Northwest: 1960 Frequency analysis: Riggs, 1961 Instruments: Barron, 1960 Presentation of data on maps : da Costa, 1960 Tritium as tool: Carlston, Thatcher, and Rhodehamel, 1960 See also Water, Water resources Callahan, Wait, and Bodhaine, Idaho: Clay deposits: Hosterman, 1960; Hosterman, Scheid, Allen, Sohn, 1961 Geochemical studies, Coeur d’Alene district: Kennedy, 1960a Geologic map, Irwin quadrangle: Gardner, 1961 Stewart Flat quadrangle: Cheney, Wolcott, and Schil- ling, 1961 Geology, Bellevue quadrangle: Schmidt, D. L., 1960 Coeur d’Alene district: Fryklund, 1961; Kennedy, 1960a Dam‘sites on upper tributaries of Columbia: Soward, 1960 Lemhi Range: Ross, C. P., 1961 Yellowstone region 2 Hamilton, 1960b Geomorphology, south central part: Ross, C. P., 1960 Geophysical investigations, Snake River Plain: Hill and Jacobson, 1961 Volcanic areas: Pakiser, 1960 OF PUBLICATIONS A—187 Idaho—Continued Ground water, Aberdeen-Springfield: Sisco, 1960 Near Moscow: Stevens, 1960 Salmon Falls area : Fowler, 1960 Snake River basin: Mundorff, 1960; Mundorfi, Crosth~ waite, and Kilburn, 1960 Mineralogy, altered Jurassic tuff: Gulbrandsen and Cress- man, 1960 Petrology, Bellevue quadrangle: Schmidt, D. L., 1960 Stratigraphy, Brazer limestone: Skipp, 1961 Illinois: Floods near Chicago: U.S. Geol. Survey, 1960e Geology, Dubuque South quadrangle: Brown and Whitlow. 1961 India: Geology and ground-water resources: Taylor, G. C.. and Pathak, 1960 Hydrology : Jones, P. H., and Subramanyam, 1961 Indiana : Coal, Brazil quadrangles : Hutchison, 1960 Dennison quadrangle: Friedman, S. A., 1961 Terre Haute quadrangle: Friedman, S. A., 1961 Flood frequency and magnitude: Green and Hoggatt, 1960 Geology, Brazil quadrangle: Hutchison, 1960 Dennison quadrangle: Friedmann, S. A., 1961 Terre Haute quadrangle: Friedman, S. A., 1961 Ground water, Bunker Hill Air Force Base : Watkins and Rosenshein, 1960 Iowa, geology, Dubuque South quadrangle: Brown and Whitlow. 1961 Isotope studies: Antarctic snows: Picciotto, de Maere, and Friedman, 1960 Deuterium in sea ice: Friedman, I., Schoen, and Harris, 1961 Geomicrobiological effect: Sisler, 1960 Problems of ore genesis: Cannon, R. S., Pierce, Antweiler, and Buck, 1961 Strontium in water : Skougstad and Barker, 1960 Uranium accumulation: Rosholt, 1961 Uranium migration: Robinson, C. S., and Rosholt, 1960 Kansas : Flood frequency: Ellis and Edelen, 1960 Geology, Douglas County: O’Connor, 1960 Ellis County: Leonard, A. R., and Berry, 1961 Gove County: Hodson and Wahl, 1960 Rush County : Leonard, A. R., and Berry, 1961 Sumner County : Walters, 1961 Trego County: Leonard, A. B., and Berry, 1961 Ground water, Douglas County: O’Connor, 1960 Ellis County: Leonard, A. R., and Berry, 1961 Gove County : Hodson and Wahl,1960 Levels, 1959: Fishel and Broeker, 1960 Rush County: Leonard, A. R., and Berry, 1961 Sumner County: Walters, 1961 Trego County: Leonard, A. R., and Berry, 1961 Streamflow characteristics: Furness, 1960 Kentucky: Geology, Cumberland Gap area: Englund and Harris, 1961 Geophysical investigations, southeastern: Johnson, R. W., 1960b Ground water, availability: Hall and Palmquist, 1960a—e; Palmquist and Hall, 1960a—g Quality of water: Hendrickson and Krieger, 1960 A—188 Kentucky—Continued Stratigraphy, Pennington and Lee formations: Englund and Smith, 1960 Water resources, eastern coal field : Price, W. E., 1960 Effects of waste oil field brines: Krieger and Hendrick- son, 1960a, b Water supplies, public and industrial: Klup and Hopkins, 1960 Lava temperatures: Ault, Eaton, and Richter, 1961 Louisiana: Geology, Calcasieu Parish : Harder, 1960a Ground water, Baton Rouge-New Orleans: Cardwell and Rollo, 1960 Calcasieu Parish : Harder 1960a Red River valley: Newcome, 1960 Southwestern: Harder, 1960b LaSalle Parish : May, H. G., 1961 State: Rollo, 1960 Maine: Aeromagnetic maps: Bromery and Gilbert, 1961; Bromery and Natof, 1961 Diorite, sphene-flecked : Milton, D. J ., 1960b Geology, central, guidebook: Griscom and Milton, 1960 Old Speck Mountain quadrangle: Milton, D. J ., 1960a Stratton quadrangle: Griscom, 1960b Paleontology, corals : Oliver, 1960a Stratigraphy, Moose River synclinorium : Boucot, 1961 Water resources: Prescott, 1960 Maryland : Geophysical investigations, Piedmont: Griscom, 1960c Mineral deposits: Pearre, 1961 ; Pearre and Heyl, 1960 Massachusetts : Geology, Bridgewater quadrangle: Hartshorn, 1960 Gay Head, Martha’s Vineyard : Kaye, 1961 Narragansett Basin: Oliver and Quinn, 1960 Geophysical investigations, Connecticut River valley: Tuttle, Kotefl, and Hartshorn, 1960 Ground water, Mattapoisett River basin: Shaw and Peter- sen, 1960 Paleontology, Foraminifera : Todd and Low, 1961 Petrology, granite-syenite complex near Salem : Toulmin, 1960a Meteorites, penetration mechanics: Shoemaker, 1960 Mexico: Geology, Morelos and adjacent areas: Fries, 1960 Geomorphology, Paricutin: Segerstrom, 1960a Michigan : Floods of 1959: Stoimenofl, 1960 Geology, Michigan basin : de Witt ,1961 Ground water, 1959: Giroux and Thompson, 1961 Mineral resources: Andalusite, Southeastern States: Espenshade and Potter, 1960 Base and precious metals, Summitville district, Colorado: Steven and Ratté, 1960 Clay deposits, Washington and Idaho : Hosterman, 1960; Hosterman, Scheid, Allen, and Sohn, 1961 Copper-uranium-vanadium, deposits in sandstones, , origin : Fischer and Stewart, 1961 Current trends in exploration: Lovering, 1960 Fluorspar, Northgate district, Colorado: Steven, 1960 Gold: Koschmann and Bergendahl, 1961 Graphite: Cameron and Weis, 1960 GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Mineral resources—Continued Iron, California : Lamey, 1961 Nevada : Shawe, Reeves, and Kral, 1961 Kyanite, Southeastern States: Espenshade and Potter, 1960 Refractory clayrocks, Colorado: Waage, 1961 Research: Bannerman, 1960 Sillimanite, Southeastern States: Espenshade and Potter, 1960 Uranium, origin: Page, L. R., 1960 Uranium-vanadium, Rifle Creek, Colorado : Fischer, 1960 Mineralogy: Aluminous clay: Schultz, 1960 Analcime and albite, altered Jurassic tufl: Gulbrandsen and Cressman, 1960 Bulk composition, zoned crystal: Griscom, 1960a Celestite, San Juan County, Utah: Gude, Young, Kennedy, and Riley, 1960 Chevkinite: Young, E. J ., and Powers, 1960 Coesite, Meteor Crater: Chao, 1960b; Chao, Shoemaker and Madsen, 1960 Wabar crater, Arabia: Chao, Fahey, and Littler, 1961 Green River formation : Milton, 0., and Fahey, 1960; Milton, 0., Fahey, and Mrose, 1960 Iron-rich mica, North Carolina: Foster, Bryant, and Hath- away, 1960 J adeite, California, New Idria district: Coleman, 1961 Neighborite: Chao, Evans, Skinner, and Milton, 1961 Kimzeyite: Milton, 0., Ingram, and Blade, 1960 Ludwigite: Schaller and Vlisidis, 1961 Norsethite: Mrose, Chao, Fahey, and Milton, 1961 Pierre shale: Schultz, Tourtelot, and Gill, 1960 Pilinite: Switzer and Reichen, 1960 Scheelite, Colorado gneisses: Tweto, 1960 Techniques: Adler, 1960b; Chao, 1960a; Coats, 1960; Cut- titta, Meyrowitz, and Levin, 1960; Gulbrandsen, 1960c; Milkey, 1960; Wilcox, 1960 Tephroite, California deposits: Hewett, Chesterman, and Troxel, 1961 Todorokite: Straczek, Horen, Ross, and Warshaw, 1960 Vernadskite: Mrose, 1961 Whewellilte, San Juan County, Utah: Gude, Young, Ken- nedy, and Riley, 1960 Zeolites: Starkey, 1960 Minnesota: Ground water, correlation of levels to temperatures: Schneider, R., 1961 Halma-Lake Bronson area : Schiner, 1960 Lyon County: Rodis, 1961; Rodis and Schneider, 1960 Mountain Iron-Virginia area: Cotter and Rogers, 1961 Nobles County: Norvitch, 1960 Magnetization, iron-formation: Bath and Schwartz, 1960, 1961; Jahren,1960 Mississippi: Irrigation, effect in Lake Washington: and Harvey, 1961 Paleontology, Ripley, Owl Creek, Prairie Blufi formations: Sohl, 1960 Public water supplies: Lang and Boswell, 1961 Stratigraphy, Pascagoula Valley: Harvey and Nichols, 1960 Ripley, Owl Creek, Prairie Bluff formations: Sohl, 1960 Tertiary and Quaternary, Pascagoula Valley: Harvey and Nichols, 1960 Mississippi Embayment, streamflow data : Speer, 1960 Harbeck, Golden, INDEX TO LIST OF PUBLICATIONS Missouri, paleontology, gastropods: Zimmerman and Yochelson, 1961 Montana: Coal resources, Birney-Broadus coal field: Warren, 1959 Geologic map, Boulder quadrangle: Becraft and Pinckney, 1961; Pinckney and Becraft, 1961 Igneous and metamorphic rocks: Merewether, 1960c Jefferson City quadrangle: Becraft, 1960a, b Geology, Bearpaw Mountains: Bryant, Schmidt, and Pe- cora, 1960 Birney-Broadus coal field: Warren, 1959 Blaine County: Zimmerman, 1960 Cenozoic, northeastern: Howard, 1960 Damsites on upper tributaries of Columbia: Soward, Deer Lodge Valley: Konizeski, McMurtrey, and Brietkrietz, 1961 Flathead region : Ross, C. P., 1%9 Gallatin Valley: Hackett, Visher, McMurtrey, and Steinhillber, 1960 Glacier National Park: Ross, C. P., 1959 Gravelly Range: Hadley, 1960b Hebgen Lake earthquake area: Hadley, 1960a; Myers, W. B., 1960 Little Bighorn River valley: Moulder, Klug, Morris, and Swenson, 1960 Lloyd quadrangle: Schmidt, R. G., Pecora, Bryant, and Ernst, 1961 St. Regis-Superior area : Campbell, A. B., 1960 Stillwater complex: Jackson, Dinnin, and Bastron, 1960 Yellowstone region: Hamilton, 1960b Glacier observations: Johnson, A., 1961 Ground water, Blaine County: Zimmerman, 1960 Deer Lodge Valley: Konizeski, McMurtrey, and Briet- krietz, 1961 Eflect of Hebgen Lake earthquake: Swenson, 1960 Gallatin Valley: Hackett, Visher, McMurtrey, and Stei-nhilber, 1960 , Little Bighorn River valley: Moulder, Klug, Morris, and Swenson, 1960 Mineralogy and petrology, Stillwater complex: Jackson 1961; Jackson, Dinnin, and Bastron, 1960 Paleontology, Madison group, Brazer dolomite: Sando and Dutro,1960 Williston Basin: Sando, 1960 Quality of water, Gallatin Valley: Hackett, Visher, Mc- Murtrey, and Steinhilber, 1960 Little Bighorn River valley: Moulder, Klug, Morris, and Swenson, 1960 Ring dikes, Antelope Creek stock: Smedes, 1960b Stratigraphy, Bighorn dolomite: Richards and Nieschmidt, 1961 Centennial Range: Cressman and Swanson, 1960 Gravelly Range: Cressman and Swanson, 1960 Little Rocky Mountains : Knechtel, 1959 Madison group, Brazer dolomite: Sando and Dutro, 1960 Madison Range: Cressman and Swanson, 1960 Three Forks shale: Rau, 1960 Surface water, Gallatin Valley: Hackett, Visher, McMurt- rey, and Steinhilber, 1960 Uranium deposits, map: Merewether, 1960c Moon: Geology: Hackman, 1961a, b; Mason, A. C., and Hackman, 1960 A—189 Moon—Continued Physiographic divisions: Mason, A. C., and Hackman, 1960 Terrain study: Mason, A. C., Elias, Hackman, and Olson, 1960 Time scale: Shoemaker and Hackman, 1960 Nebraska: Geology, Chadron area: Dunham, 1961 Little Blue River basin : Johnson, C. R., 1960 Platte-Republican Rivers watershed: Johnson, C. B., 1960 Yankton area : Simpson, H. E., 1960 Ground water, levels in wells 1960: Keech, 1961 Little Blue River basin: Johnson, C. R., 1960 Platte-Republican Rivers watershed: Johnson, C. R., 1960 Heavy minerals, Harrison formation : Peckham, 1961 Nevada: Dessication fissures, Black Rock—Smoke Creek Deserts: Willden and Mabey, 1961 Geologic map, Bare Mountain quadrangle: Cornwall and Kleinhampl, 1960a Climax stock : Houser and Poole, 1960a Humboldt County: Willden, 1961 Osgood Mountains quadrangle: Hotz and Willden, 1960 Geology, Beatty area: Cornwall and Kleinhampl, 1960b Jackson Mountains: Willden, 1960a Lincoln County: Tschanz, 1960; Tschanz and Pampeyan, 1960 Nevada Test Site areas: Gibbons, Hinrichs, Dickey, McKeown, Poole, and Houser, 1961; Houser and Poole, 1960b; McKoewn and Dickey, 1961; Wil- marth, Healey, Clebsch, Winograd, Zietz, and Oliver, 1960 Geophysical investigations, Nevada Test Site: Bunker, 1961; Dickey, 1960; Diment, Stewart, and Roller, 1960, 1961; Izett, 1960; Wilmarth, Healey, Clebsch, Winograd, Zietz, and Oliver, 1960 Ground water, cooperative investigations: Loeltz, 1960a Nevada Test Site: Clebsch, 1960; Clebsch and Barker, 1960; Wilmarth, Healey, Clebsch, Winograd, Zietz, and Oliver, 1960 Newark Valley: Eakin, 1960 Pine Valley: Eakin, 1961 Hydrologic data, Nevada Test Site: Wilmarth, Healey, Clebsch, Winograd, Zietz, and Oliver, 1960 Hydrologic effects of nuclear explosions: Clebsch, 1960 Hydrology, Humboldt River project : Loeltz, 1961 Iron deposits: Shawe, Reeves, and Kral, 1961 Metasomatism, Humboldt Range: Tatlock, Wallace, and Silberling, 1960 Paleontology, fusulinids: Douglass, 1960a Natchez Pass formation: Silberling, 1961 Spring-water source, Ash Meadow Valley: Loeltz, 1960b Stratigraphy, White Pine County: Palmer, 1960b Structural features, eastern : Drewes, 1960 Thrusting, northwestern: Willden, 1960b Welded tuffs, Toiyabe Range: Masursky, 1960 New England: Flood frequency: Benson, 1961 Geochronology, alkalic rocks: Toulmin, 1961 Glacial geology, coast: Supson and Spencer, 1960 Hydrology: Benson, 1961 New Hampshire, water resources, suburban and rural, south- eastern: Meyers and Bradley, 1960 A—190 New Jersey : Flood-plain inundation, Somerville—Manville area: Thomas, D. M., 1961 Geology, Frenchtown quadrangle: Drake, McLaughlin, and Davis, 1961 Hydrochemical facies, Englishtown sand: Seaber, 1960 Petrography, dolomites: Zadnik, 1960 Surface-water supply 1950~55 : McCall and Lendo, 1960 New Mexio: Domal structures, southeast: Vine, 1960 Exploration, Rio Arriba County : Dane, 1960b Flood of May 1955 : Vaudrey, 1960 Flood water, conservation, White Sands Missile Range, Herrick, 1961 Geologic map, Cabezon—3 quadrangle: Holzle, 1960 Geologic section, Carlsbad Caverns to Project Gnome site: Cooper, 1960 Geology, Carlsbad Coverns: Moore, G. W., 1960a Lea County: Ash, 1961b Rio Chama country: Baltz and Ash, 1960; Baltz, Lamb, and Ash, 1960 Geophysical investigations, northeastern: Andreasen, Kane, and Zietz, 1961 Ground water, Acoma Indian Reservation : Rapp, 1960b Chaves County: Hood, Mower, and Grogin, 1960 Gallup area : West, 1961 Gila National Forest: Trauger, 1960 Lea County: Ash, 1961b Otero County: Herrick, 1960b; Hood, 1960a, b San Ildefonso Pueblo Grant: Rapp, 1960a Well levels, 1955: Reeder, Doty, Mower, Bjorklund, Benge, Busch, Hood, and Berkstresser, 1960 Well levels, 1956: Reeder, Doty, Cooper, Mower, Bjork- lund, Busch, Benge, and Mourant, 1960 White Sands Proving Ground: Herrick, E. H., 1960a, c J icarilla Apache Indians: Ash, 1960 Quality-of—water map, Curry County: Grogin, 1960 Roosevelt County : Grogin, 1960 Stratigraphy, Dakota sandstone: Dane, 1960a Mancos shale: Dane, 1960a Raton Mesa coal region: Johnson, R. B., and Roberts, 1960 Sangre de Cristo Mountains : Baltz and Read, 1960 Silver City region: Pratt and Jones, 1961 New York : Aeromagnetic maps, Adirondacks region: Balsley, Hill, and Meuschke, 19613, ‘b; Balsey, Rossman, and Hill, 1961a—f Geology, Taconic rocks: Zen, 1960b Ground water, Dutchess County: Simmons, E. T., Gross- man, and Heath, 1961 Suffolk County: Hoffman and Lubke, 1961 Paleontology, Hamilton group: Boardman, 1960 Salt-water body, Magothy formation, Nassau County: Lusczynski and Swarzenski, 1960 Sedimentary petrology, Potsdam sandstone: Wiesnet, 1961 Stratigraphy, Java formation: de Witt, 1960 Streamflow, effect of reforestation: Schneider, W. J., and Ayer, 1961 North Carolina : Geochemical reconnaissance, Concord quadrangle: Bell, H., and Overstreet, 1960; Overstreet and Bell, 1960a GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS North Carolina—Continued Geology, Grandfather Mountain area : Bryant and Reed, 1960 Wilmington-New Bern area : LeGrand, 1960a Cape Hatteras: Brown, 1960 ; Kimrey, 1960a Coastal plain : Brown, P. M., and Floyd, 1960 Dare Beaches: Kimrey, 1961 Wilmington-New Bern area : LeGrand, 1960a Mica, iron-rich, Grandfather Mountain area : Foster, Bryant and Hathaway, 1960 Quality of water 1957—58: Woodard and Thomas, 1960 Quarry dewatering problem, New Bern : Kimrey, 1960b North Dakota : Geology, Cenozoic, northwestern: Howard, 1960 Souris River area 2 Lemke, 1960 Williston basin: Sandberg, 1961 Test drilling, Walhalla area : Adolphson, 1960 Ohio : Floods, at Mount Vernon : U.S. Geol. Survey, 1961g 1959: Archer, 1960; Cross, 1961 Glacial geology, Wisconsin deposits: White, 1960 Ground water, Fairborn area : Walton and Scudder, 1960 Middle Branch Valley: Winslow, 1960 Quality of water 1946—58: Hubble and Collier, 1960 Oklahoma : Age, Johns Valley shale, J ackfork sandstone, Stanley shale: Miser and Hendricks, 1960 Geology, McCurtain County: Davis, L. V., 1960 Ground water, Beaver Creek basin: Hart, 1961b McCurtain County: Davis, L. V., 1960 State: Leonard, A. R., 1960 Salt springs : Ward, P. E., 1961 Oregon: Ground water, Snake River basin : Newcomb, 1960 Stratigraphy, John Day formation : Fisher and Wilcox, 1960 Thrust faults, northern Wallowa Mountains: Smedes, 1960a Pacific Coast States : Paleontology, ammonites: Imlay, 1960a Stratigraphy, Cretaceous formations: Popenoe, Imlay, and Murphy. 1960 Pacific Islands: Drilling operations, Eniwetok : Ladd and Schlanger, 1960 Geology, Ifaluk Atoll : Tracey, Abbott, and Arnow, 1961 Paleontology: Cole, 1960; MacNeil, 1960; Todd, 1960; Todd and Low, 1960 Typhoon effects : Blumenstock and others, 1961; Fosberg, 1961c—e; McKee, 1961a—c Pacific Northwest, flood frequency: Bodhaine, 1960 Paleobiogeography : Cloud, 1961 Paleobotany: Scott, R. A., 1960 Paleontology : Amomnites: Cobban and Gryc, 1961; Imlay, 1960a, b, 1961; Jones, 1961 ; Reeside and Cobban, 1960 Bryozoa : Boardman, 1960 Cephalopods 2 Teichert and Kummel, 1960 Conodonts: Ash, 1961a Corals: Oliver, 1960a, b; Sando, 1960, 1961 Foraminifera : Cole, 1960; Douglass, 1960b, 1961; Herrick, 1960; Todd, 1960; Todd and Low, 1960, 1961 ; Wood- ring and Malavassi, 1961 Fusulinids: Douglass, 1960a; Myers, D. A., 1960 Gastropoda : MacNeil, 1960; Sohl, 1960; Yochelson, 1960a, b, 1961a, b; Zimmerman and Yochelson, 1961 INDEX TO LIST Paleontology—Continued Graptolites : Ross, R. J ., 1961 Mollusks: Silberling, 1961 ; Taylor, D. W., 1960, 1961 ; Woodring and Malavassi, 1961 Ostracodes: Sohn, 19601), c Pelecypods: Jones and Gryc, 1960 Sponge, western Wyoming: Finks, Yochelson, and Sheldon, 1961 Status: Yochelson, 1960c Techniques: Sohn, 1960a Tri-lobites : Palmer, 1960c Vertebrates: Lewis, 1960a,b Pennsylvania : Aeromagnetic maps: Bromery, Zandle and others, 1960a—g, 1961a—m Drainage basin, central: Brush, 1961 Geology, anthracite region: Trexler, 1960 Frenchtown quadrangle: Drake, Davis, 1961 Illinoian outwash: Lockwood and Meisler, 1960 Schuylkill-Susquehanna River area : Kehn, 1960 Sweet Arrow fault : Wood, G. H., and Kehn, 1961 Mineral deposits : Pearre and Heyl, 1960 Sedimentary petrology, western Pennsylvania shale: Pat- terson, 1960 Streamflow: Brush, 1961 Petrographic techniques: Bailey and Stevens, 1960a,b; Leonard, B. V., 1960 Petrography of pottery: Hunt, 1960b Petroleum : Metal content: Ball and others, 1960; Hyden, 1961 Origin: Breger, 1960 Uranium content: Bell, K. G., 1960b; Hyden, 1961 Petrology: ‘ Aleutian Islands volcanic suites : Byers, 1961 Ash flows : Ross, C. S., and Smith, 1961 ; Smith, R. L., 1960a,b Calderas: Smith, R. L., Bailey, and Ross, 1960 Hawaiian volcanic flows: Richter and Murata, 1960 Lopoliths: Hamilton, 1960c, f Peridotite—gabbro complexes: Thayer, 1960 Stillwater complex, Montana: Jackson, 1961; Jackson, Din- nin, and Bastron, 1961 Zeolite facies: Zen, 1961 Physical properties : Acoustic relaxation, chromium: Peselnick and Meister, 1961 Elasticity, Solenhofen limes-tone: Peselnick and Outer— bridge, 1961 Magnetic susceptibility, gallium: Pankey, 1960 Liver: Senftle and Thorpe, 1961 Titanium dioxide: Senftle, Pankey, and Grant, 1960 Magnetization, basalt: Cox, 1960a Iron-formation, Minnesota : Bath and Schwartz, 1960; J ahren, 1960 Pulseatransient behavior, brine-saturated sandstones: Kel- ler, G. V., 1960 Thermoluminescence, Nevada Test Site: Dickey, 1960 Plant ecology: Fosberg, 1960a,b, 1961a,b; Hack and Goodlett, 1960; Shacklette, 1961 McLaughlin, and OF PUBLICATIONS A—191 Puerto Rico: Floods, Sept. 1960: Barnes, H. H., and Bogart, 1961 Geologic map, Cayey quadrangle: Berryhill and Glover, 1960 Central Aguirre quadrangle: Berryhill, 1960 Comerio quadrangle: Pease and Briggs, 1960 J uncos quadrangle: Broedel, 1961 Geology, tunnels, Utuado area : Kaye and Dunlap, 1960 Iron and copper prospects, J uncos quadrangle: Broedel, 1961 Laterization : Briggs, 1960 Shoreline changes: Briggs, 1961 Stratigraphy and structure, southwestern: Mattson, 1960 Water resources: Arnow and Bogart, 1960; Arnow and Crooks, 1960; Bogart, Arnow, and Crooks, 1960 Radioactive waste disposal: Bowen, Edgerton, Mohrbacker, and Callahan, 1960; de Witt, 1961; Love and Hoover, 1961; Nace, 1960; Repenning, 1961; Simpson, E. S., 1960 Radioactivity detection, scintillation counting: Martinez and Senftle, 1960 Reefs, relation to water circulation: Tracey, 1961 Rhode Island: Geology, Kingston quadrangle: Kaye, 1960 Narragansett Basin : Oliver and Quinn, 1960 Ground water, Hunt River basin: Allen, 1960 Ground—water map, North Scituate quadrangle: Pollock, 1960 Oneco quadrangle: Johnson, K. E., Mason, and DeLuca, 1960 Quonochontaug quadrangle: LaSala and Johnson, 1960 Voluntown quadrangle : Randall, Bierschenk, and Hahn, 1960 Hydraulic characteristics, glacial outwash : Lang, Bier- schenk, and Allen, 1960 Saudi Arabia : Age determinations : Aldrich and Brown, 1960 Geographic map: Bramkamp and Ramirez, 1960a, b; Bram- kamp, Ramirez, and Brown, 1961 Geologic map: Bramkamp and Ramirez, 1961 Geology: Brown, G. F., and Jackson, 1960 Geomorphology: Brown, G. F., 1960 Sedimentary petrology: Browns Park formation: Chisholm, Bergin, and Pritchard, 1961 Grain-size analysis: Cadigan, 1961 Harrison formation: Peckham, 1961 Potsdam sandstone: Wiesnet, 1961 Techniques: Tourtelot, 1961 Thickness and consolidation, deep-sea sediments: Davis, G. H., 1960 South Carolina : Geology, Kings Mountain belt: Overstreet and Bell, 1960b Hydrologic factors, limestone terranes : Siple, 1960b Mineralogy, kyanite pseudomorphs: Overstreet, Overstreet, and Bell, 1960 Paleontology, Foraminifera : Herrick, S. M., 1960 Southeastern States, floods, February—March 1961: Barnes, H. H., and Somers, 1961 South Dakota: Geology, Black Hills: Norton and Redden, 1960 Chadron area : Dunham, 1961 Yankton area : Simpson, H. E., 1960 A—192 South Dakota—Continued Ground water: Davis, R. W., Dyer, and Powell, 1961 Sedimentary petrology, Minnelusa Sandstone: Bowles and Braddock, 1960 Stratigraphy, Inyan Kara group: Wolcott and Gott, 1960 Irish Creek: Tourtelot and Schultz, 1961 Uranium deposits, southwestern Black Hills: Gott, Brad- dock, and Post, 1960 Southern States, Ground-water resources: Southwestern States : Hydrology, lower Colorado River area: McDonald, 1961 Paleontology, Gastropoda : Yochelson, 1960b Tectonic framework: Hunt, 1961 Spectroscopy: Photometric titration attachment: Meyrowitz and Beasley, 1961 Quantitative : Bastron, Barnett, and Murata, 1960 Semiquantitative: Barnett, 1961 X-ray : Adler, 1960a, c; Chodos and Engel, 1961 Stratigraphy : Cambrian, early Late: Palmer, 1960a Cretaceous, Pacific Coast: Popenoe, Imlay, and Murphy, 1960 Java formation, New York: de Witt, 1960 Mowry shale, US. and Canada : Reeside and Cobban, 1960 Northern Rockies: Sandberg, 1961b Park City formation, Wyoming: Finks, Yochelson, and Sheldon, 1961 Permian salt: Ward, P. E., 1960 Pierre shale, Great Plains: Gill, J. R., Schultz, and Tourte- lot,1960 Ripley, Owl Creek, Prairie Bluff formations: Sohl, 1960 Streams: Channels, surges: Rantz, 1961 b, c Depth-discharge relations: Dawdy, 1961 Drainage basins, channels, and flow characteristics: Brush, 1961 Charactistics, central Pennsylvania : Brush, 1961 Flow in alluvial channels: Simons, D. B., Richardson, and Albertson, 1961 Flow-distance i-n drainage basin: Busby and Benson, 1960 Flow resistance, irregular channels: Leopold, Bagnold, Wolman, and Brush, 1960 Gaging network in US. : McCall, 1961 Glacial, morphology and hydrology: Fahnestock, 1960a Sediment discharge computation: Colby and Hubbell, 1961 Sedimentation characteristics: Hubbell, 1960 Tektites: Chemical composition and magnetic properties: Friedman. I., Thorpe, and Senftle, 1960 a, b Gay Head, Massachusetts: Kaye, Schnetzler, and Chase, 1961 Tennessee: Flood frequency: Jenkins, 1960a Geology, Blockhouse quadrangle: Neuman and Wilson, 1960 Cumberland Gap area : Englund and Harris, 1961 Mascot-Jefferson City zinc district: Brokaw, 1960 Northeasternmost: King, P. B., and Ferguson, 1960 Wildwood quadrangle: Neuman, 1960a Geophysical investigations, Clark Hollow: Johnson, R. W., 1961 Paleontology, Ripley, Owl Creek, Prairie Bluff formations: Sohl, 1960 LaMoreaux, 1960 GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Tennessee—Continued Stratigraphy, Ocoee series: Neuman, 1960b Pennington and Lee formations: Englund and Smith, 1960 Ripley, Owl Creek, Prairie Bluff formations: Sohl, 1960 Sequatchie and Rockwood formations: Wedow, 1960 Tuscaloosa formation: Marcher and Stearns, 1960 Streams, low-flow frequency: Eaton, 1960 Texas: Geology, Carson County: Long, 1961 Gray County: Long, 1961 Grayson County: Baker E. T., 1960 Grosvenor quadrangle: Terriere, 1960 Hale County : Cronin and Wells, 1960 Hays County: DeCook, 1960 Ground water, Carson County: Long, A. T., 1961 El Paso : Leggart, 1960 a, D Gray County: Long, A. T., 1961 Grayson County : Baker, E. T., 1960 Hale County : Cronin and Wells, 1960 Hays County : DeCook, 1960 Karnes County: Anders, 1960 McCullouch County: Mason, 0. C., 1961 Rio Grande valley: Baker, R. C., 1961 Southern High Plains: Cronin, 1960 Paleontology, Fusulinidae: Myers, D. A., 1960 Stratigraphy, Boquilas flags and Austin chalk: Freeman, 1961 Cisco group: Myers, D. A., 1960b Precambrian: Harbour, 1960 Wichita group: Stafford, 1960 Surface-water composition: Hughes and Jones, 1961 United States, geology, sedimentary basins: Love and Hoover, 1961 Uranium: Petroleum and rock asphalt: Bell, K. A., 1960b Salt pan basins : Bell, K. A., 1960 Utah : Argillic alteration, East Tintic district: Lovering and Shepard, 1960 Botanical prospecting, Circle Cliffs area: Kleinhampl and Koteff, 1960 Deer Flat area : Froelich and Kleinhampl, 1960 Deformation of Bonneville shorelines: Crittenden, 1960 Geologic map, Aspen Grove quadrangle: Baker, A. A., 1961a Brighton quadrangle: Baker, A. A., 1961b Cedar Mesa-Boundary Butte area : O’ Sullivan, 1961 Confusion Range: Hose, Repenning, and Ziony, 1960 Dutch John Mountain quadrangle: Hansen, 1961a Goslin Mountain quadrangle: Hansen, 1961a Heber quadrangle: Baker; A. A., 19610 Mount Peale 2 NE quadrangle: Weir and Puffett, 1960a Mount Peale 2 SE quadrangle: Weir, Dodson, and Puifett, 1960 Mount Peale 4 NE quadrangle: Weir, Carter, Puftet, and Gualtieri, 1960 » Mount Peale 4 SE quadrangle: Weir and Puffet, 1960b Mount Peale 4 NW quadrangle: Weir, Puffett, and Dodson, 1961 Orem quadrangle: Baker, A. A., 1961d Strawberry Valley quadrangle, Utah: Baker, A. A., 1961e Thomas and Dugway Ranges: Staatz and Carr, 1961 Willow Creek Butte quadrangle: Hansen, 1961b INDEX TO LIST Utah—Continued Geology, Clay Hills area : Mullens, 1960 East Tintic district: Levering and Morris, 1960. Little Valley, Quaternary deposits: Goode and Eard- ley, 1960 Timpanogos Cave quadrangle: Baker and Crittenden, 1961 Geophysical investigations, East Tintic district: Cook, 1960 Ground water, Middle Canyon, Oquirrh Mountains: Gates, J. S., 1961 Sevier Valley : Young, Carpenter, 1961 Mineral deposits, Elk Ridge area: Campbell, R. H., and Lewis, 1961 Lisbon Valley: Kennedy, 1960b; Weir and Puflett, 1960c Temple Mountain: Hawley, 1960 Mineralogy, Green River formation: Milton, Charles, Chao, Fahey, and Mrose, 1960 Paleontology, Madison group, Brazer dolomite: Sando and Dutro, 1960 Permian rocks, Duchesne County: Yochelson,, Cheney, Van Sickle, and Dunkle, 1961 Precambrian rocks, Uinta Mountains : Hansen, 1960 Salt anticllnes, development: Cater and Elston, 1961 Early growth, Elston, 1960 Stratigraphy, Brazer dolomite: Sando and Dutro, 1960 Hermosa formation: Bite, 1960 Madison group: Sando and Dutro, 1960 Mesaverde group: Brodsky, 1960 Triassic, salt anticline region: Stewart, J. H., and Wilson, 1960 Structural geology, western: Drewes, 1960 Structural history, Uncompahg're front: Elston and Shoe- maker, 1960 Water supply, Capitol Reef : Marine, 1961 Vermont: Geology, Taconic rocks: Zen, 1960b Petrology, slate belt: Zen, 1960a Stratigraphy, Chipman formation: Cady and Zen, 1960 Virginia : Forest ecology: Hack and Goodlett, 1960 Geology, Cumberland Gap area: Englund and Harris, 1961 Geomorphology: Hack, 1960; Hack and Goodlett, 1960 Hydrology, Fort Belvoir area : Durfor, 1961 Stratigraphy, Pennington and Lee formations: England and Smith, 1960 Volcanoes, growth : Eaton and Murata, 1960 Washington : Clay deposits: Hosterman, 1960; Hosterman, Scheid, Allen, and Sohn, 1961 Coal, depositional environment: Gower, Vine, and Snavely, 1960 Geologic map, Boundary and Spirit quadrangles: Yates, 1961 Deep Lake quadrangle: Yates and Ford, 1960 Des Moines quadrangle: Waldron, 1961a Orting quadrangle: Crandell, 1961a Port Angeles-Lake Crescent area: Brown, R. J ., Gower, and Snavely, 1960. Poverty Bay quadrangle: Waldron, 1961b Sumner quadrangle: Crandell, 1961b Wilkeson quadrangle: Crandell, 1961c Geology, Columbia Basin Project area : Walters and Grolier, 1960 Pysht quadrangle: Gower, 1960 R. A., 1960; Young and or PUBLICATIONS A—193 Washington—Continued Glacier observations 2 Johnson, A., 1960 Ground water, Columbia Basin Project area: Walters and Grolier, 1960 Laurier and Ferry border stations: Walters, 1960 Water resources, artificial recharge: Price, C. E., 1961; Russell, 1960 Water: Evapotranspiration measurement: Leppanen and Harbeck, 1960 Flow in pipes: Kindsvater, 1961 Geochemistry: Back, 1960a—c, 1961 Ground water, computation of velocity from temperature data: Stallman, 1960 Lake, effect of irrigation on level: Harbeck, Golden, and Harvey, 1961 Primer: Leopold and Langbein, 1960 Quality, research and basic data in: Geurin, 1960 Rain-gages, evaporation losses from: Gill, H. E., 1960 River hydraulics : Rantz, 1961b, c Sample collection and analysis: Rainwater and Thatcher, 1960 Streamflow, effect of reforestation: Svhneider, W. J ., and Ayer,1961 Potomac River: Searcy and Davis, 1961 Time of travel, Ohio River: Steacy, 1961 Use, in mining and beneficiating iron ore: Mussey, 1961b In Southeast river basins 1960: MacKichan and Kammerer, 1961 Measuring by saltcedar: van Hylckama, 1960 Water plant-s, iron content: Oborn, 1960b Water resources: Aquifer analog models : Stallman, 1961 Borehole methods for analyzing specific capacity: Bennett and Patten, 1960 Development and management: Conover, 1960 Evaporation and transpiration, bibliography: Robinson, G. W., and Johnson, 1961 Evaporation control research : Cruse and Harbeck, 1960 Evaporation suppression : Harbeck, 1960 Gaging station records, graphical correlation: Search, 1960 Ground water, artificial recharge of aquifer: Price, C. E., 1961 Barometric efiect on: Stephens, 1960 Contamination: Rorabaugh, 1960a Effect of earthquakes: Hopkins, W. B., and Simpson, 1960 Effect of nuclear explosions: Clebsch, 1960 Effect of oil-field brines, Kentucky: Krieger and Hen- drickson, 1960a, b Effect of surface loading: Odom, 1961 Effect of temperature and viscosity on recharge: Snie- gocki, 1960 Estimating aquifer constants: Rorabaugh, 1960b Flow: Skibitzke, Chapman, Robinson, and McCullough, 1961; Wyrick, 1960a Land subsidence due to withdrawal: Poland, 1960a, b Law: Thomas, H. E., 1961 Levels, northeastern states: U.S. Geo]. Survey, 1960h Management: Conover, 1960 Motion, laboratory study: Skibitzke, 1960c Pattern of flow : da Costa and Bennett, 1960 Recharge: Taylor, G. H., 1960a Research: McGuinness, 1960 1&—194 Water resources—Continued Ground water—Continued Rights: Piper, 1960 Salt intrusion in coastal aquifers: Henry, 1960 Time, distance, and drawdown relations, pumped basis: Kunkel,1960 Jet drilling methods : Cederstrom and Tibbitts, 1961 Management in alluvial valley: Moulder, 1960a Mississippi embayment study: Cushing, 1960 River-basin yields, statistical evaluation : Riggs, 1960 Role of wetland: Baker, 1960 Sea-water intrusion, island aquifer : Mink, 1960b Specific yield, bibliography: Johnson, A. 1., Morris, and Prill,1960 Springs, origin, development, protection: Taylor, G. H., 1960b Supply and requirements: Mussey, 1961a Surface water, definitions: Langbein and Iseri, 1960 Instruments: Barron, 1960 Quality: U.S. Geol. Survey, 1960i—m, 1961a, f Records: U.S. Geol. Survey, 1960a—c Supply: U.S. Geol. Survey, 1960m—z, aa—ff, 1961b—f Water wells: Development in limestone terrane: LaMoreaux and Powell, 1961 Fluctuations of levels: Hart, 1961a Yield, production by step-down tests: Sanford and West, 1960 Water Witching: Marsh, 1961 West Virginia : Martens Cave, meteorological observations: Davies, 1960 Water resources, Kanawha County: Doll, Wilmarth, and Whetstone, 1960 Wisconsin: Geology, Black Earth Creek basin : Cline, 1960 Florence area: Dutton, 1960 Geophysical investigations, Wausau area: Allingham and Bates, 1960 Ground water, Black Earth Creek basin: Cline, 1960 Stratigraphy, Little Commonwealth area: Johnson, R. W., 1960a Surface water, Black Earth Creek basin: Cline, 1960 Wyoming: , Chemical weathering, Wind River Range: Hembree and Rainwater, 1961 Coal resources, Buffalo-Lake DeSmet area : Mapel, 1959 Deformation and deposition, related to fuel occurrence: Love, McGrew, and Thomas, 1961; Thomas, H. D., Love. and McGrew, 1961 Wind River Basin: Keefer, 1960 GEOLOGICAL SURVEY RESEARCH 1961—SYNOPSIS OF RESULTS Wyoming—Continued Folding, west flank, Black Hills: Izett, Mapel, and Pillmore, 1960 Geologic map, Dutch John Mountain quadrangle: Hansen, 1961a ' Goslin Mountain quadrangle: Hansen, 1961a Igneous and metamorphic rocks: Merewether, 1960b Irwin quadrangle: Gardner, 1961 Geology, Buffalo-Lake DeSmet area : Mapel, 1959 Carlile quadrangle: Bergendahl, Davis, and Izett, 1961 Devils Tower : Robinson, C. S., 1960 Owl Creek area : Berry and Littleton, 1961 Platte County : Morris and Babcock, 1960 Yellowstone region: Hamilton, 1960b Ground water, Bear River valley : Robinove and Berry, 1960 Northern Bridger basin: Gordon, King, Haynes, and Cummings, 1960 Owl Creek area: Berry and Littleton, 1961 Platte County : Morris and Babcock, 1960 Hydrologic conditions, Horseshoe Creek Valley: Weeks, 1960 Mineralogy, altered Jurassic tuff: Gulbrandsen and Cressman, 1960 Green River formation: Milton and Fahey, 1960 Paleontology, Madison group: Sando and Dutro, 1960 Park City formation: Finks, Yochelson, and Sheldon, 1961 . Petroleum and natural gas: Thomas, H. D., Love, and McGrew, 1961 Quality of water, Bear River valley: Robinove and Berry, 1960 Reef Creek detachment fault: Pierce, 1960 Sedimentation and erosion, Fivemile Creek: Hadley, R. F., 1960 Solution breccias, Minnelusa sandstone: Bowles and Brad- dock, 1960 Stratigraphy, Bighorn dolomite: Richards and Nieschmidt, 1961 . Brazer dolomite: Sando and Dutro, 1960 Inyan Kara group : Wolcott and Gott, 1960 Madison group: Sando and Dutro, 1960 Pennsylvanian and Permian: Maughan and Wilson, 1960 Phosphoria formation: Gulbrandsen, 1960a, b Wind River formation: Soister, 1960 Taconite deposits, Fremont County: Bayley, 1960 Uranium deposits, map: Merewether, 1960b Yellowstone region: Late Cenozoic tectonics: Hamilton, 1960c Volcanism: Hamilton, 1960c U,S. GOVERNMENT PRINTING OFFICE: 1961 O—-608400 Geological Survey , Research 1961 Short Papers in the Geologic and Hydrologic Sciences, Articles. 1-146 &S',GEOLOGICAL SURVEY PROFESSIONAL PAPER 424—B / .’ v',_v_r_“ ' A _ i fi—i Q ‘sv 9" Short Papers in the Geologic and Hydrologic Sciences, Articles 1-146 GEOLOGICAL SURVEY RESEARCH 1961 GEOLOGICAL SURVEY PROFESSIONAL PAPER 424—B Scientific ii-oz‘es mm] summaries of investigatiom prepared oy memoers of t/ze Geologic, Water Resources, and Conservaz‘iofl Divisions in Me fields ofgeo/ogy, flydro/ogy, and allied sciences UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 21961 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. .88th Z4402 .m m6: 2389:: 98:: 23 .8 $9853 a $38.3 :w w:w::3:8 8 36:38 98:: Eofi :358 3063888 wNisfifism @850 $385333 33% :8wa :W 88886 8— 8: mac: 8 m9: 853 K98% 8&8: .8 3853: :o 52:38on 8 8296038 Ba: .8 3:8:88:=o::w o8 28m .85: PE. 8 98 233 $23 558m 23 .8 EEEZQ 83:83:80 8:: £888me 8935 “28886 23 .8 38:88 N3 388:: £8:me 63.29: 65“.. $88.8»: Swofioww .8 mew 0:: :m 38.35 .8 32.3?» a :o @893 98% as 36205 2:33 mi? :3: ofi mm m3: 8:?» mo 8833 :8.“ :w waxiwfifisw on 53 .53 “cm :3. 95:8 3:8“: NH may .83 .8?» 3%: 23 wfihfi 855m 32888.0 85$ @883 23 :3 :83 mo 33me 2:888 88 ocsgwom 8:8 Qmogmmom v t D A. > '| ’ r y I‘ J A i} IIII '« .. L J § r y D L V ‘ 4|?rlrrb v CONTENTS 5 _ V t Foreword ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, V Geology of metalliferous deposits ‘_ 1. Temperature of formation of a Precambrian massive sulfide deposit, Copper King mine, Front Range, 0010., P. K. Sims and Priestley Toulmin, 3d ‘5 2. Coffinite in uranium vein deposits of, the Front Range, Colorado, by P. K. Sims, E. J. Young, and W. N. Sharp... 3. Structural control of epigenetic uranium deposits in carbonate rocks of northwestern New Mexico, by Lowell ‘ S. Hilpert .............. J 4. Origin of uranium and gold in the quartzite-conglomerate of the Serra de Jacobina, Brazil, by Max G. White ..... Hydrologic studies , . | 5. Magnitude and frequency of floods in suburban areas, by R. W. Carter... 5 6. Effect of artificial storage on peak flow, by William D. Mitchell... 7. Distinctive characteristics of glacier runoff, by Mark F. Meier and Wendell V. Tangborn ..................................... * 8. Recent hydrologic trends in the Pacific Northwest, by Wilbur D. Simons Precipitation as a variable in the correlation of runoff data, by William J. Schneider ................................................ Regional low flow frequency analysis, by H. C. Riggs . Modified conveyance-slope applied to development of stage-fall-discharge ratings, by William C. Griffin ___________ 12. Flow in an artificially roughened channel, by H. J. Koloseus and Jacob Davidian ' 1 13. Dimensions of some stable alluvial channels, by Stanley A. Schumm i 14. Some factors influencing streambank erodibility, by I. S. McQueen ‘ 15. An example of channel aggradation induced by flood control, by Norman J. King ................................................... 16. Some effects of microclimate on slope morphology and drainage basin development, by Richard F. Hadley ......... ‘ 17. Hydrologic significance of buried valleys in glacial drift, by Stanley E. Norris and George W. White .................. 1 18. Plan to salvage evapotranspiration losses in the central Sevier Valley, Utah, by Richard A. Young and Carl ‘ H. Carpenter , , 19. Relation between storage changes at the water table and observed water-level changes, by R. W. Stallman _____ 20. The significance of vertical flow components in the vicinity of pumping wells in unconfined aquifers, by R. W. r Stallman 21. Methods for study of evapotranspiration, by O. E. Leppanen ,,,,,,,,, r 22. Water movement and ion distribution in soils, by R. F. Miller and K. W. Ratzlaif ______________________________________________________ y 23. Compression of elastic artesian aquifers, by S. W. Lohman 24. Measurement of compactiOn of aquifer systems in areas of land subsidence, by Ben E. Lofgren ____________________________ . 25. The coefficient of storage in a region of major subsidence caused by compaction of an aquifer system, by J. F. Poland ‘ e 26. Compaction of an aquifer system computed from consolidation tests and decline in artesian head, by Raymond E. Miller t 27. Development of an ultrasonic method for measuring stream velocities, by H. 0. Wires __________________________________________ 28. Preliminary design of an electric analog of liquid flow in the unsaturated zone, by R. W. Stallman _______________________ r 29. Direct—reading conductivity bridge, by I. S. McQueen and C. R. Daum » w Geology and hydrology of eastern United States , 30 Age of the “ribbon rock” of Aroostook County, Maine, by Louis Pavlides, Robert B. Neuman, and William B. N. Berry 31. Ratio of thorium to uranium in some plutonic rocks of the White Mountain plutonic-volcanic series, New Hampshire, by Arthur P. Butler, Jr. ...... V 32. Uranium and thorium in the older plutonic rocks of New Hampshire, by John B. Lyons _______________________________________ . 33. Distance between basins versus correlation coefficient for annual peak discharge of streams in New England, ' by Jacob Davidian and M. A. Benson L 34. Pleistocene stratigraphy of Boston, Massachusetts, by C. A. Kaye ‘ 7 , 35. Iron ores of St. Lawrence County, northwest Adirondacks, N. Y., by B. F. Leonard and A. F. Buddington _______ , 36. Characteristics of seiches on Oneida Lake, N Y., by John Shen > V Page III 12 14 17 20 21 23 25 26 28 29 32 34 36 39' 41 43 45 47 49 52 54 58 60 63 65 67 69 71 73 76 80 VI Geology 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. Geology 47. 48. 49. 5o. 51. 52. 53. 54. 55. 56. 57. 5s. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. CONTENTS and hydrology of eastern United States—Continued Variations of pH with depth in anthracite mine-water pools in Pennsylvania, by Wilbur T. Stuart and Thomas A. Simpson ______ Angular unconformity separates Catskill and Pocono formations in western part of Anthracite region, Penn- sylvania, by J. Peter Trexler, Gordon H. Wood, Jr, and Harold H Arndt Reefs in the Fort Payne formation of Mississippian age, south—central Kentucky, by Robert E. Thaden, Richard Q. Lewis, J. Mark Cattermole, and Alfred R. Taylor The Tuscaloosa gravel in Tennessee and its relation to the structural development of the Mississippi embay- ment syncline, by Melvin V. Marcher Systematic pattern of Triassic dikes in the Appalachian region, by Philip B. King ____________________________________________________ Rainfall and minimum flows along the Tallapoosa River, Alabama, by H. C. Riggs ............................................... Stress model for the Birmingham red iron-ore district, Alabama, by Thomas A. Simpson ______________________________________ Water-temperature distribution in a tidal stream, by Frederick W. Wagener Recent lead-alpha age determinations on zircon from the Carolina Piedmont, by William C. Overstreet,,Henry Bell, III, Harry J. Rose, Jr., and Thomas W. Stern Tidal fluctuations of water levels in wells in crystalline rocks in north Georgia, by J. W. Stewart _____________________ and hydrology of western conterminous United States A new map of western conterminous United States showing the maximum known or inferred extent of Pleistocene lakes, by J. H. Feth Recent flood-plain formation along the Cimarron River in Kansas, by S. A. Schumm and R. W. Lichty ............ Abnormal bedding in the Savanna sandstone and Boggy shale in southeastern Oklahoma, by Thomas A. Hendricks .................. Reservoir evaporation and seepage, Honey Creek, Tex., by F. W. Kennon Pre-Pennsylvanian Paleozoic stratigraphy, Mockingbird Gap quadrangle, New Mexico, by George 0. Bachman Preliminary results of test drilling in depressions on the High Plains, Lea County, N. Mex., by John S. Havens- Lower member of Mural limestone of Early Cretaceous age, Bisbee quadrangle, Arizona, by Philip T. Hayes and Edwin R. Landis Origin of cross- strata in fluvial sandstone layers in the Chinle formation (Upper Triassic) on the Colorado Plateau, by John H. Stewart ........... Fossil woods associated with uranium on the Colorado Plateau, by Richard A. Scott ________________________________________________ Late Cenozoic events of the Leadville district and upper Arkansas Valley, Colorado, by Ogden Tweto ............ Movement of the Slumgullion earthflow near Lake City, Colo., by Dwight R. Crandell and D. J. Varnes ........ Relations of metals in lithosols to alteration and shearing at Red Mountain, Clear Creek County, Colo., by P. K. Theobald, Jr., and C. E. Thompson Hydrology of small grazed and ungrazed drainage basins, Badger Wash area, western Colorado, by Gregg C. Lusby ........... Abandonment of Unaweep Canyon, Mesa County, Colo., by capture of the Colorado and Gunnison Rivers, by S. W. Lohman Tripartition of the Wasatch formation near De Beque in northwestern Colorado, by John R. Donnell ............... Diamictite facies of the Wasatch formation in the Fossil basin, southwestern Wyoming, by J. I. Tracey, Jr., S. S. Oriel, and W. W. Rubey .............. Tongues of the Wasatch and Green River formations, Fort Hill area, Wyo., by S.‘ S. Oriel .................................... Age of the Evanston formation, western Wyoming, by W. W. Rubey, S. S. Oriel, and J. I. Tracey, Jr ............. Permafrost and thaw depressions in a peat deposit in the Beartooth Mountains, northwestern Wyoming, by William G. Pierce... Evidence for Early Cretaceous folding in the Black Hills, Wyo., by Glen A. Izett, Charles L. Pillmore, and William J. Mapel Structure of the Clark Fork area, Idaho- Montana, by J. E. Harrison, D. A. Jobin, and Elizabeth King ............... Pleistocene geology of the central part of the Lemhi Range, Idaho, by Edward T. Ruppel and Mortimer H. Hait, Jr The Michaud delta and Bonneville River near Pocatello, Idaho, by Donald E. Trimble and Wilfred J. Carr____ Volcanic ash beds as stratigraphic markers in basin deposits near Hagerman and Glenns Ferry, Idaho, by Howard A. Powers and Harold E. Malde ................. Patterned ground of possible solifluction origin at low altitude in the western Snake River Plain, Idaho, by Harold E. Malde Collapse structures of southern Spanish Valley, southeastern Utah, by G. W. Weir, W. P. Pufl’ett, and C. L. Dodson ...... Age relations of the Climax composite stock, Nevada Test Site, Nye County, Nevada, by F. N. Houser and F. G. Poole. Rhyolites in the Egan range south of Ely, Nev, by Daniel R. Shawe Tectonic significance of radial profiles of alluvial fans in western Fresno County, Calif., by William B. Bull Page 8—82 84 88 90 93 96 98 100 103 107 110 112 114 117 119 123 125 127 130 133 136 139 141 144 147 149 151 153 154 156 159 163 164 167 170 173 176 178 182 A _A_‘ , _1_A. (’ Geology 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. Geology 89. 90. Reconnaissance of the Kandik and Nation Rivers, east-central Alaska, by Earl E. Brabb _______________________________________ CONTENTS and hydrology of western conterminous United States—Continued Soil- moisture storage characteristics and infiltration rates as indicated by annual grasslands near Palo Alto, Calif., by F. A. Branson, R. F. Miller, and I. S McQueen Causes and mechanics of near- -surface subsidence in western Fresno County, Calif. by William B. Bull ____________ Specific gravity of sandstones in the Franciscan and related Upper Mesozoic formations of California, by William P. Irwin ........ Some extremes of climate in Death Valley, Calif., by T W. Robinson and Charles B. Hunt _____________________________ Stratigraphy of desert varnish, by Charles B. Hunt Use of archeology in Recent stratigraphy, by Charles B. Hunt and Alice P. Hunt _______________________________________________ Evidence of strike-slip movement on northwest-trending faults in Mojave Desert, California, by T. W. Dibblee, Jr. ................... Zoning of saline minerals at Deep Spring Lake, Calif. by Blair F. Jones Effects of rainfall and geology on the chemical composition of water in coastal streams of California, by J. H. Feth Ground water from coastal dune and beach sands, by E. R. Hampton Mass budget of South Cascade Glacier, 1957—60, by Mark F. Meier Competence of a glacial stream, by Robert K. Fahnestock Structural barrier reservoirs of ground water in the Columbia River basalt, by R. C. Newcomb ________________________ and hydrology of Alaska and Hawaii Xenolithic nodules in the 1800—1801 Kaupulehu flow of Hualalai Volcano, by Donald H. Richter and Kiguma J. Murata ,,,,,,,,,,,,, Geology of Puerto Rico 91. 92. 93. Hydrothermally altered rocks in eastern Puerto Rico, by Fred A. Hildebrand... Andalusite-topaz greisen near Caguas, east-central Puerto Rico, by Fred A. Hildebrand ..................................... Ash-flow deposits, Ciales quadrangle, Puerto Rico, and their significance, by Henry L. Berryhill, Jr. ................. Paleontology and plant ecology 94. Replaced Paleocene Foraminifera in the Jackson Purchase area, Kentucky, by I. G. Sohn, S. M. Herrick, and T. W. Lambert 95. Coal-ball occurrences in eastern Kentucky, by James M. Schopf 96. Age of the Ohio Creek conglomerate, Gunnison County, 0010., by D. L. Gaskill .................................................... 97. Bioherms in the upper part of the Pogonip in southern Nevada, by Reuben J. Ross, Jr., and Henry R. Cornwall ....................... 98. Soil moisture under juniper and pinyon compared with moisture under grassland in Arizona, by R. F. Miller, F. A. Branson, I. S. McQueen, and R. C. Culler 99. Corals from Permian rocks of the northern Rocky Mountain region, by Helen Duncan .......................................... 100. Occurrences of the Permian gastropod Omphalotrochus in northwestern United States, by Ellis L. Yochelson 101. Pennsylvanian rocks in southeastern Alaska, by J. Thomas Dutro, Jr., and Raymond C. Douglass .................... Geophysics 102. Poisson’s ratio of rock salt and potash ore, by R. E. Warrick and W. H. Jackson .......................................... 103. Frequency content of seismograms of nuclear explosions and aftershocks, by S. W. Stewart and W. H. Diment .................................................... 104. Gravity, volcanism, and crustal deformation in and near Yellowstone National Park, by L. C. Pakiser and Harry L. Baldwin, Jr. 105. Gravity, volcanism, and crustal deformation in the Snake River Plain, Idaho, by D. P. Hill, Harry L. Bald- win, Jr., and L. C. Pakiser .......................................................... 106. Gravity, volcanism, and crustal deformation in Long Valley, Calif., by L. C. Pakiser ............................................ 107. Gravity study of the structural geology of Sierra Valley, Calif., by W. H. Jackson, F. R. Shawe, and L. C. Pakiser .......... Mineralogy, geochemistry, and petrology 108. 109. 110. 111. 112. Distribution of niobium in three contrasting comagmatic series of igneous rocks, by David Gottfried, Lillie Jenkins, and Frank S Grimaldi Beryllium content of cordierite, by Wallace R. Griffitts and Elmo F. Cooley Germanium content of enargite and other copper sulfide minerals, by Michael Fleischer ........................................ Chlorine and fluorine in silicic volcanic glass, by Howard A. Powers Electronprobe analysis of schreibersite (rhabdite) in the Canyon Diablo meteorite, by I. Adler and E. J. Dwornik VII Page B—184 187 189 192 194 195 197 199 202 204 206 211 213 215 218 219 222 224 227 228 230 231 233 235 237 239 241 243 246 248 250 254 256 259 ' 259 261 263 VIII CONTENTS Page Mineralogy, geochemistry, and petrology—Continued 113. The synthesis of large crystals of andersonite, by Robert Meyrowitz and Daphne R. Ross. . ,,,,, B'— 266 114. Unit- cell dimension versus composition in the systems: PbS— CdS, PbS— —PbSe, ZnS—ZnSe, and CuFeS. m— CuFeSIm, by Philip M. Bethke and Paul B Barton, Jr ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 266 115. Unit—cell edges of cobalt- and cobalt- -iron- bearing sphalerites, by Wayne E. Hall ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 271 116. X— —ray diffractometer method for measuring preferred orientation in clays, by Robert H. Meade ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 273 117. Molybdenum content of glacial drift related to molybdenite-bearing bedrock, Aroostook County, Maine, by F. C. Canney, F. N. Ward, and M. J. Bright, Jr. ,,,,,,,,,,, 276 118. Anomalous heavy minerals in the High Rock quadrangle North Carolina, by Amos M. White and Arvid A Stiomquist 278 119. Iron content of soils and trees, Beaver Creek strip mining area, Kentucky, by Eugene T. Oborn ,,,,,,,,,,,,,,,,,,,,,,, 279 120. Mineralogy of the Olive Hill clay bed, Kentucky, by John W. Hosterman and Sam H. Patterson ,,,,,,,,,,,,,,,,,,,,,,, 280 121. Four environments of thorium—, niobium-, and rare-earth-bearing minerals in the Powderhorn district of southwestern Colorado, by D. C. Hedlund and J. C. Olson 283 122. Rhenium in plant samples from the Colorado Plateau, by A. T. Myers and J. C. Hamilton ................................... 286 123. Classification of elements in Colorado Plateau uranium deposits and multiple stages of mineralization, by A. T. Miesch ................................................................................................ 289 124. Hydrogeochemical anomalies, Fourmile Canyon, Eureka County, Nev., by R. L. Erickson and A. P. Marranzino ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 291 125. Grantsite, a new hydrated sodium calcium vanadyl vandate from New Mexico and Colorado—a pre11m1nary description, by A. D. Weeks, M. L. Lindberg, and Robert Meyiowitz 293 126. Insoluble residues and Ca: Mg ratios in the Madison group, Livingston, Mont., by Albert E. Roberts ........... 294 127. Manganese oxide minerals at Philipsburg, Mont. by William C. Prinz 296 128. Uranium and radium in ground water from igneous terranes of the Pacific Northwest, by Franklin B. Barker and Robert C. Scott .......... 298 129. Shorgite in the Furnace Creek area, California, by James F. McAllister 299 Geology and hydrology applied to engineering and public health 130. Economic significance of a buried bedrock bench beneath the Missouri River flood plain near Council Bluffs, Iowa, by Robert D. Miller ...................... 301 131. Relation of supports to geology in the Harold D. Roberts Tunnel, Colorado, by E. E. Wahlstrom, L. A. Warner, and C. S. Robinson 303 132. Landslides along the Uinta fault east of Flaming Gorge, Utah, by Wallace R. Hansen ..................................... 306 Exploration and mapping techniques 133. Geochemical prospecting for copper deposits hidden beneath alluvium in the Pima district, Arizona, by Lyman C. Huff and A. P. Marranzino . 308 134. Measurement of bulk density of drill co1e by gamma- ray absorption, by Carl M. Bunker and Wendell A. Bradley ...................... 310 135. Mechanical control for the time-lapse motion-picture photography of geologic processes, by Robert D. Miller, Ernest E. Parshall, and Dwight R. Crandellw 313 136. Liquid-level tiltmeter measures uplift produced by hydraulic fracturing, by Francis S. Riley ............................ 317 137. A method of recording and representing geologic features from large—diameter drill holes, by Elmer H. Baltz and James E. Weir, Jr. ...... 319 Analytical and petrographic methods 138. Methods for decomposing samples of silicate rock fragments, by John C. Antweiler ............................................. 322 139. Fatigue in scintillation counting, by Francis J. Flanagan 324 140. A simplified method of concentrating and preparing carbonate shells for C” age determinations, by Thomas C. Nichols, Jr. ...... 326 141. Colorimetric determination of' 11‘01’1 in small samples of sphalerite, by Leonard Shapiro and Martha S. Toulmin 328 142. Indirect semiautomatic determination of alumina with EDTA, by J. I. Dinnin and C. A. Kinser .................... 329 143. Determination of copper in plant ash with neo- cuproine, by Claude Huffman, Jr., and Dwight L. Skinner _______ 331 144. Direct— —reading spectrometric technique for determining major constituents in natural water, by Joseph Hafl'ty and A. W. Helz 333 145. Rapid quantitative estimates of quartz and total 1ron in silicate rocks by X- -ray difl'raction, by D. B. Tatlock ...... 334 146. 'The Koberg- Daum wind- direction and wind- velocity recorder, by G. E. Koberg and C. R. Daum ......................... 337 Index Subject .................... 77777777777777777777777777777777777777777777777777777777777777 339 Author ......... 343 _________ 344 GEOLOGICAL SURVEY RESEARCH 1961 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGI‘C SCIENCES, ARTICLES 1—146 GEOLOGY 0F METALLIFEROUS DEPOSITS 1. TEMPERATURE OF FORMATION OF A PRECAMBRIAN MASSIVE SULFIDE DEPOSIT, COPPER KING MINE, FRONT RANGE, COLORADO By P. K. SIMS and PRIESTLEY TOULMIN, 3d, Denver, 0010., and Washington, D. C. The Copper King mine, at Prairie Divide in Lari— mer County, Colo., contains ore deposits of two types and ages—massive sulfide-magnetite deposits of Precambrian age and a vein uranium deposit of early Tertiary age. The ore deposits and the geologic setting of the mine have been described previously (Sims, Phair, and Moench, 1958). This report pre- sents some new data concerning the temperature of formation of coexisting sphalerite, pyrrhotite, and pyrite from one of the massive sulfide deposits in the mine. The sulfide-magnetite deposit is a small, elongate, roughly tabular body that is mainly in cummingto- nite-anthophyllite skarn. The ore minerals form massive layers and lenses a few feet in maximum breadth and width and a few tens of feet in length that conform to the foliation and lineation of the host rock. The deposit consists, in order of de- creasing abundance, of pyrite, sphalerite, pyrrhotite, chalcopyrite, magnetite, and molybdenite. The re- lation of the ore minerals to the host rock clearly indicates that they formed mainly by replacement of amphiboles. The deposit and its host rock are enclosed entirely within a biotite-muscovite granite of Precambrian age, which has been called Silver Plume granite (Lovering and Goddard, 1950, pl. 1). Magnetite from the deposit and monazite from a pegmatite in the granite have both been dated as late Precambrian (Phair and Sims, 1954). Except for molybdenite, the ore minerals are closely associated and commonly intergrown, al- though the quantities and proportions of the sep- arate mineral phases differ from one ore-bearing layer or lens to another. The close spatial association of the ore minerals and the textural relations Ob- served in the field and in polished sections indicate that they were deposited during a single stage. The minerals crystallized in the commonly observed paragenetic order: magnetite, pyrrhotite, pyrite, sphalerite, and chalcopyrite. The sphalerite is dark reddish-brown and apparently homogeneous. It con- tains oriented blebsand blades of chalcopyrite and sparse randomly distributed blebs of pyrrhotite, which are interpreted to have formed from exsolu- tion on cooling. , The temperature of formation of the deposit can be estimated by use of the sphalerite and pyrrhotite geothermometers (Kullerud, 1953; Arnold, 1958). Barton and Kullerud (1958) have extended the earlier work of Kullerud (1953) to show that if sphalerite formed in equilibrium with pyrrhotite (with or without pyrite) below a temperature of 600°C, the temperature of formation can be deter- mined from the FeS content of the sphalerite, using the solvus curve determined for the binary systems FeS—ZnS. The sphalerite at the Copper King mine is in contact with both pyrrhotite and pyrite and contains exsolved blebs of pyrrhotite, and therefore probably crystallized in equilibrium with these minerals. The sphalerite in five samples from various parts of the deposit exposed in the mine workings contains 13.6 to 15.6 formula percent FeS, as shown in table 1, which corresponds to a range in tempera- ture of crystallization from 440°C. to 490°C. (Bar- ton and Kullerud, 1958, fig. 33). The low amounts of manganese, copper, and cadmium in solid solu- tion in the sphalerite would have little effect on the solubility of FeS in ZnS. B—2 TABLE 1.1.—Spectrochemical analyses of sphalerite and esti— mated temperatures of crystallization [Analyses by R. G. Havens, U.S. Geological Survey] Estimated Samples Analyses (percent) temperature of formation (degrees Serial No. Field No. Fe FeS 1 Mn Cu Cd Zn centigrade) Z E—1860 ...... A .......... 9.1 15 6 0 13 0.63 0.26 0.015 490110 1861 ..... B .......... 8.6 14 8 13 1.1 .28 .014 480110 1858 ...... CK—69 ..... 8.2 14 1 12 .95 28 013 455i10 1857 ...... CK—201.. 7.9 13 6 13 .52 26 .012 440i10 1859 ...... UG-20 ..... 7.9 13 6 13 .69 26 .011 44021: 10 1 Formula percent. 2 Not corrected for total rock pressure. If the rock cover at the time of mineralization was 5 miles, the sphalerite temperatures would be raised about 50° C. Compositions of pyrrhotite from two samples (CK—64 and CK—3) collected from the same part of the mine as the sphalerite samples have been deter- mined from measurements of duoz, (Arnold and Reichen, 1959). Pyrrhotite CK—64, associated with pyrite, sphalerite, and chalcopyrite, has dmm equal to 2.063A, corresponding to 47.03 atomic percent metals. Assuming Fe to be the only metal present, we may apply the solvus curve in the system FeS— F382 to find a temperature of 400°C. This tempera- ture is somewhat lower than that indicated by the composition of the associated sphalerite. A similar relationship between “pyrrhotite tem eratures” and “sphalerite temperatures” has been f und in several other studies (for example: Stone, 1959; Skinner, 1958) and probably is a consequence of different reaction rates in the two systems. Comparison of the reaction-rate data on sphalerite in the system FeS—ZnS (Kullerud, 1953, p. 98) and on pyrrhotite in the system FeS—FeS2 1 shows that pyrrhotite equilibrates with pyrite at 325°C. as rapidly as sphalerite equilibrates with FeS at 750°C. Thus as a pyrite—pyrrhotite—sphalerite assemblage cools slowly in nature, one would expect the pyrrho- tite to continue to react at temperatures below that at which the sphalerite composition had been effec- tively “quenched in” by decreasing reaction rates. Pyrrhotite CK—3 is also associated with pyrite, sphalerite, and chalcopyrite, and is cut by a late generation of pyrite probably related to the Tertiary uranium mineralization. Its (102) peak is much 1Pyrrhotite-pyrite equilibrium relations between 325° C. and 743° C. by Ralph G. Arnold, unpublished Ph.D. thesis, Princeton Univ., 1958, p. 41. 6b GEOLOGICAL SURVEY RESEARCH 1961 broader than that of pyrrhotite CK—64, presumably reflecting a range of composition. The mean value of (1.102, is approximately 2.066A, corresponding to a composition of 47.3 atomic percent metals. Both this higher mean metal content and the greater spread in composition of pyrrhotite CK—3 probably reflect partial reaction with the late pyrite. Pyrrho- tite that has a composition of 47.3 atomic percent metals is in equilibrium with pyrite at about 325°C. If the massive sulfide deposit is genetically related to the granite, as seems probable from their close spatial association and their similar absolute ages (Sims, Phair, and Moench, 1958, p. 200), the de- posit necessarily formed after the adjacent granite had crystallized and cooled to about 500°C. On this assumption, it is unlikely that the ore-forming solu- tions could have come from a source near the sul- fide body; instead they must have been derived from a more distant source, possibly subjacent crystalliz- ing magma. REFERENCES Arnold, R. G., 1958, The Fe-S system: Annual report of the Director of the Geophysical Laboratory, 1957—58, Car- negie Inst. Washington Year Book 57, p. 218—222. Arnold, R. G., and Reichen, Laura, 1959, Application of the pyrrhotite X-ray determinative curve to natural pyrrho- tites: Annual report of the Director of ”the Geophysical Laboratory, 1957—58, Carnegie Inst. Washington, Year Book 58, p. 155—156. Barton, P. B., Jr., and Kullerud, Gunnar, 1958, The Fe-Zn-S System: Annual report of the Director of the Geophysical Laboratory 1957—58, Carnegie Inst. Washington Year Book 57, p. 227—229. Kullerud, Gunnar, 1953, The FeS-ZnS system, a geological thermometer: Norsk geol. tidsskr., v. 32, p. 61—147. Levering, T. S., and Goddard, E. N., 1950, Geology and ore deposits of the Front Range, Colorado; U.S. Geol. Survey Prof. Paper 223, 319 p. . Phair, George, and Sims, P. K., 1954, Paragenesis and age of the uranium minerals in the Copper King mine, Larimer County, Colo. [abs.]: Geol. Soc. America Bull., v. 65, p. 1385. - Sims, P. K., Phair, George, and Moench, R. H., 1958, Geology of the Copper King uranium mine, Larimer County, 0010.: U.S. Geol. Survey Bull. 1032—D, p. 171—221. Skinner, B. J., 1958, The Geology and metamorphism of the Nairne pyritic formation, a sedimentary sulfide deposit in South Australia: Econ. Geology, v. 53, p. 546—562. Stone, J. G., 1959, Ore genesis in the Naica district, Chihua- hua, Mexico: Econ. Geology, v. 54, p. 1002—1034. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 2. COFFINITE IN URANIUM VEIN DEPOSITS OF THE FRONT RANGE, COLORADO By P. K. SIMS, E. J. YOUNG, and W. N. SHARP, Denver, Colo. Cofiinite, a uranous silicate with hydroxyl sub- stitution, is associated with pitchblende in some hydrothermal vein deposits in the Front Range, and locally is an important ore mineral. Previously re- ported occurrences of the mineral in the United States (Stiefi', Stern, and Sherwood, 1956; Frondel, 1958) have been mainly from the black, unoxidized vanadium-uranium ores of the Colorado Plateau. The known occurrences of coflinite in the Front Range are listed in table 1. At the Copper King, ~ Fair Day, and Foothills mines, and possibly also the Schwartzwalder mine, coifinite constitutes a substan- tial part of the uranium ore; at the other localities it is sparse. TABLE 1.—Known occuw ‘LCBS of coflinite in the Front Range Mine District or area County Principal associated minerals Source of data Blue Jay Jamestown Boulder Fluorite, uraninite, and Identified by X-ray powder uranothorite photographs, this report. Copper King Prairie Divide Larimer Pitchblende, siderite, pyrite, Reported by Sims, Phair, sphalerite, marcasite, quartz and Moench (1958). Fair Day Jamestown Boulder Pitchblende, pyrite, quartz, Identified by X-ray powder sphalerite, chalcopyrite photographs and in polished and thin sections, this report. Foothills Idledale Jefferson Pitchblende, pyrite, quartz, Identified by X—‘ray powder potassium feldspar, carbonates photographs, this report. Old Leyden coal Leyden Jefferson Meta-tyuyamunite, autunite, Reported by A. J. Gude, 3rd; uranophane, and pyrite see also Gude and McKeown (1953). Schwartzwalder Ralston Buttes Jefferson l’itchblende, pyrite, quartz, Reported by J. D. Schlottman, carbonate minerals, potassium U. S. Atomic Energy Commis- feldspar . sion (oral communication, 1960). Stanley Idaho Springs Clear Creek l’itchblende, pyrite, sphalerite, Reported by R. H. Moench, and a carbonate mineral (oral communication, 1961). Cofiinite typically occurs in the Front Range in veins that are characterized by abundant open cavities and conspicuous crustification, features gen- erally considered diagnostic of epithermal veins (Lindgren, 1933, p. 444—445). It is associated with pitchblende, pyrite, and sparse sulfides that rarely are visible megascopically, chiefly sphaler‘ite (nearly pure ZnS), chalcopyrite, and marcasite. 'Quartz— or quartz, ankerite, and potassium feldspar—is the principal gangue mineral in most deposits, but siderite is dominant in one, the Copper King deposit. Two exceptions to this mode of occurrence are known. At the Stanley mine, cofl‘inite fills fractures that cut sulfide andgangue minerals of a mesother- mal vein; at the Old Leyden coal mine, cofiinite is associated with fractured and silicified coal. The coflinite is black in hand specimen and gen- erally cannot be distinguished megascopically from pitchblende. It can be identified with certainty, how- ever, by X-ray powder photographs, and in some ores at least can be recognized in thin and polished sec- tions. Polished thin sections are particularly useful for study of the cofiinite ores. In transmitted light, the coffinite is brown or yellowish brown, translucent to different degrees, and mostly isotropic. It occurs predominantly as aggre- gates of extremely small particles that form spheroi- dal or other rotund forms. Rarely, the aggregates have a visible fibrous structure, with the fibers oriented perpendicular to the colloform bands. The fibrous aggregates show a generally weak but con- spicuous dichroism (darker color perpendicular to fibers). In general, the optical properties agree with well crystallized cofi‘inite from the Woodrow mine, B__4 GEOLOGICAL SURVEY RESEARCH 1961 Laguna district, New Mexico (R. H. Moench, writ- ten communication, 1961). Refractive indices, reflectivity, and unit cell sizes of coflinite from two mines are listed below: Coflinite Locality Refractive Reflectivity 1 Unit cell size index (percent) (A) Fair Day mine ............... 1.7710005 7.8-9.8 A, =6.935 Co =6.212_ Copper King mine ............ (2) 8.2—8.6 A, =6.971 Co =6.286 lDetermined in orange light with a Hallimond visual microphotometer, according to the method described by Leonard (1960). 2Coffinite is finely admixed with siderite and other minerals, and a re- liable refractive index was not determined. Index is known to be lower than for coffinite from the Fair Day mine. The pitchblende associated with coflinite from the Fair Day mine has a reflectivity of 13 in orange light. As the coffinite from both the Fair Day and Copper King mines contains some finely intergrown pitchblende, the measured reflectivities are slightly higher than would be obtained from homogeneous cofl‘inite. . In reflected light, coflinite resembles pitchblende in its optical and physical properties and in having rotund forms and ubiquitous shrinkage cracks. It is gray and isotropic, and has a hardness similar to that of pitchblende. It can' be distinguished from pitchblende because it has (a) weak internal reflec- tions, (b) a lower reflectivity, and (c) a local radial- fibrous structure in colloform aggregates, which can be seen most clearly under oil immersion. Metallographic studies of the black uranium ores from the Fair Day mine, which have a delicate collo- form structure, indicate that coflinite formed later than pitchblende. In all sections examined, coffinite embays and veins pitchblende, in a manner such as that illustrated in figure 2.1. The upper photomicro- graph shows a spheroidal grain of pitchblende that is almost surrounded by cofiinite. The coflinite em- bays the host irregularly and has replaced much of the outer part of the original sphere. One veinlet extends completely across the sphere. Replacement clearly preceded complete solidification of the host, for shrinkage cracks in the pitchblende in part ex- tend outward into the coffinite, suggesting that shrinkage was partly simultaneous in both minerals. If the pitchblende had completely crystallized and shrunk before it was replaced, the coffinite should occur preferably in and along the shrinkage cracks. In detail, the contacts between pitchblende and cofli- nite are sharp, even when observed under high mag- nification, and are commonly bulbous or mammillary FIGURE 2.1.—Photomicrographs of polished sections of ore from Fair Day mine (6, coffinite; p, pitchblende). in outline. In the lower photomicrograph, of part of a coflinite veinlet that transects a spheroidal grain of pitchblende, it can be seen that the veinlet is highly irregular and consists of coalescing aggregates of individual rotund forms that are smoothly convex toward the host. The largest node has conspicuous growth bands. This photomicrograph shows also a small veinlet of cofiinite that appears to follow a shrinkage crack in pitchblende; this relation is rare in .the ores. Paragenetic studies of the black uranium ores from the Copper King mine are less definitive. Typi- cally, tiny rotund forms of pitchblende, at most a few microns in diameter, occur in dominantly collo- form coffinite. Even under magnification of several hundred diameters, there is no evidence that the pitchblende is corroded by coffinite. Warp» 1 1""! k. ‘Y—'——. . , . V ‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B_5 The occurrences of cofiinite in the Front Range indicate that the mineral characteristically forms in veins in a low temperature-pressure environment. Cofl‘inite- has not been identified from the uranium- bearing mesothermal sulfide veins of the Front Range mineral belt (Sims, 1956), except at the Stanley mine (table 1), where cofiinite is clearly later than the dominant vein minerals and therefore could have formed under considerably lower temperatures than the main mineral assemblage. REFERENCES Frondel, Clifi‘ord, 1958, Systematic mineralogy of uranium and thorium: U.S. Geol. Survey Bull. 1064, 400 p. Gude, A. J., 3d. and McKeown, F. A., 1953, Results of explora- tion at the Old Leyden coal mine, Jefferson County, Colo- rado: U.S. Geol. Survey open-file report. Leonard, B. F., 1960, Reflectivity measurements with a Halli- mond visual microphotometer: Econ. Geology, v. 55, p. 1306—1312. Lindgren, Waldemar, 1933, Mineral deposits, 4th ed.: New York, McGraw-Hill, 930 p. Sims, P. K., 1956, Paragenesis and structure of pitchblende- bearing veins, Central City district, Colorado: Econ. Geology, v. 51, p. 739—756. Sims, P. K., Phair, George, and Moench, R. H., 1958, Geology of the Copper King uranium mine, Larimer County, Colorado: U.S. Geol. Survey Bull. 1032-D, p. 171—221. Stiefl’, L. R., Stern, T. W., and Sherwood, A. M., 1956, Coffin- ite, a uranous silicate with hydroxyl substitution: A new mineral: Am. Mineralogist, v. 41, p. 675—688. ’5? 3. STRUCTURAL CONTROL OF EPIGENETIC URANIUM DEPOSITS IN CARBONATE ROCKS OF NORTHWESTERN NEW MEXICO By LOWELL S. HILPERT, Salt Lake City, Utah Work done in cooperation with the U.S. Atomic Energy Commission A compilation of data on more than 100 uranium deposits in carbonate rocks in northwestern New Mexico shows that the deposits are generally asso- ciated with tectonic structures. The deposits occur mostly in the Colorado Plateaus Province in the Todilto limestone of Jurassic age; and a few occur in the Basin and Range Province in the San Andres and Madera limestones of Permian and Pennsyl- vanian ages, respectively (fig. 3.1). All the deposits are considered to be of epigenetic origin—that is, they were emplaced some time after the host rocks were deposited. In the Todilto limestonelthe uranium minerals are of primary and secondary origin. The primary min- erals, which are finely disseminated, are uraninite and coflinite, accompanied by the vanadium oxides haggite and paramontroseite (Truesdell and Weeks, 1959, p. 1689—1960). These minerals fill pore spaces, and replace limestone along silty layers. They are accompanied by the accessory minerals pyrite, hema- tite, fluorite, and barite (Laverty and Gross, 1956, p. 195—201). The secondary uranium minerals, gen- erally closely associated with the primary minerals above the water table, are yellow and yellow-green uranyl vanadates and silicates, which coat the walls of fractures and the pore spaces along silty layers in the limestone. The Todilto deposits are roughly tabular with ir- regular outline, thus resembling many uranium de- posits in sandstone in the Colorado Plateaus Prov- ince and elsewhere. They generally conform to the bedding but in detail cut across it. More than 50 deposits have been mined, and individual deposits have yielded from a few tons to as much as 100,000 tons of uranium ore. Control of the uranium deposits in the Todilto limestone has been ascribed to diagenetic folds and larger scale fold and fault structures (Gabelman, 1956, p. 389, 391—392). The diagenetic folds are referred to hereafter as intraformational folds. However, a close spatial relation between the de- posits and the larger scale structures is difl‘icult to establish. In fact, these structures may be younger than the primary uranium minerals (Hilpert and Moench, 1960, p. 443—444) as they probably are related to a system of large-scale structures that has B-6 GEOLOGICAL SURVEY RESEARCH 1961 I | I l ' |1o9° 108° COLORADO 107° 106° "37° -—~__—.l__ __.—--- __ __—.3.Z: NEW MEXICO pa \2 l (I ' ' I <9 Shipmck V ¢ e, 03 e Farming“ Tierra Amarilla l I e ' < R 1 0 AR R I B A 2 \ Z 2 g' '2 \ fi' ' ‘8 \ lg S A N J U A N Z I I l _ _ __ _ I I I El:- — "' "' + '_ _ I I I s A N D 0 V A L I I | Santa Fe 3 M c K I N L E Y I < Lu l 0 Gallup ' p. I 2 AA gig I I I l - _ A ' — _ \ I l I if: \ _ __ ._ _ __. I Grants 0 A Alb V 9 uquerque I J I 13w 0 — --*— 35+ _|_VALENCIA o +BERNALILLO ' 35” F _ __ _ i A E \ _ I I A \ 33A 9 ‘o\ ,— --x, | o z - -— - —- — —— - ‘ o < l 109° I EXPLANATION I A _. ._ ' ._ _ — — , IT 0 R R A N c E Uranium deposit or group of deposits in E \ I“ Todilto limestone l 2 E \ I m N A ' I Uranium deposit in San Andres limestone ! I A _ _ _._. .. — A CATRON' SOCORRO A Uranium deposit in Madera limestone A (l) ? 1'0 1l5 210 215M|LES A ,__34° Socorro 34"“ 108° l 107° 106° 1 11 I FIGURE 3.1.—Map of northwestern New Mexico showing uranium deposits in the Todilto, San Andres, and Madera limestones. “4‘ ‘ a t V :1. LA lgr v 4r! ‘rv SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—7 been interpreted to be later than early Eocene in age (Hunt, 1938, p. 74—75). On the other hand, the deposits are closely related to the intraformational folds because they generally occur along the flanks . and in some places along the axes of the folds. The intraformational folds are of many types. Some are broad and open, some are recumbent, others are parts of larger intraformational folds, and still others are associated with intraformational faults that have displacements of only a few inches or more. In size the folds range from a few inches to about 30 feet in width and amplitude, and from a few feet to hundreds of feet in length. They are generally confined to the Todilto limestone, but some extend a few feet into the overlying or underlying formations. Many occur in clusters and if so the axes of individual folds may be parallel or sub- parallel. These structures are developed best in McKinley and Valencia Counties and a few occur in western San Juan and Rio Arriba Counties (fig. 3.1). These intraformational folds are apparently tec- tonic in origin, as they are related to tectonic fold- ing (Hilpert. and Moench, 1960, p. 437—444). They are probably of Jurassic or Early Cretaceous age; and the associated primary ore minerals are prob- ably of Late Cretaceous or early Tertiary age (Hil- pert and Moench, 1960, p. 450). Deposits in the San Andres and Madera lime- stones also occur where the rocks have been de- formed. These deposits may be wholly secondary in origin, as only secondary minerals have been identi- fied—but it is possible that primary minerals will ultimately be revealed by further exploration or study. In the San Andres limestone the uranium is in conspicuous yellow vanadates that coat fracture surfaces, bedding surfaces, and fill open space in the rock where it has been broken by faulting. Two deposits in north-central Socorro County (fig. 3.1) are in a sandy zone in the limestone where it is broken by a north-trending high-angle fault. The largest mineralized zone, from which some ore has been mined, is about 50 feet in diameter and 35 feet thick. A deposit also occurs in the San Andres lime- stone in Valencia County, but the geologic relations are not clear. At this locality a yellow uranium mineral has been reported to occur in fractures in the San Andres limestone near igneous intrusive rocks. Two uranium deposits also occur in a sandy zone in the Madera limestone in north-central Socorro. County (fig. 3.1) Where the limestone has been brecciated along a north-trending high-angle fault. In these deposits also the uranium occurs in yellow vanadates and possibly in silicates that coat the fracture surfaces. The largest mineralized zone is about 100 feet in diameter where exposed at the sur- face, and is several feet thick. The highest grade material is near the fault and some ore has been mined. The deposits in the San Andres and Madera lime- stones are probably of late Tertiary age or younger because the faults that apparently control the de- posits displace the Datil formation (Wilpolt and Wanek, 1951), which is probably of late Tertiary age. ' In summary, the uranium deposits in carbonate rocks in northwestern New Mexico are almost en- tirely associated with folds, faults, and minor frac- tures. These deposits are of epigenetic origin; they occur in two geologic provinces in formations of three geologic ages, and they probably represent two different periods of mineralization. Because they were formed under diverse geologic conditions in which the tectonic structures are the only fea- tures common to all, it must be concluded that locali- zation of the uranium deposits is controlled by the tectonic structures. A brief review of the geologic literature reveals that most epigenetic uranium de- posits in carbonate rock are controlled by tectonic structures. Therefore, it is concluded that only de- formed carbonate rocks are good host rocks for epi- genetic uranium deposits. REFERENCES Gabelman, J. W., 1956, Uranium deposits in limestone, in Page, L. R., and others, compilers, Contributions to the geology of uranium and thorium by the United States Geological Survey and Atomic Energy Commission for the United Nations International Conference on peaceful uses of atomic energy, Geneva, Switzerland, 1955: U.S. Geol. Survey Prof. Paper 300, p. 387—404. Hilpert, L. S., and Moench, R. H., 1960, Uranium deposits of the southern part of the San Juan Basin, New Mexico: Econ. Geology, v. 55, p. 429—464. Hunt, C. B., 1938, Igneous geology and structure of the Mount Taylor volcanic field, New Mexico: U.S. Geol. Survey Prof. Paper 189—B, p. 51—80. Laverty, R. A., and Gross, E. B., 1956, Paragenetic studies of uranium deposits of the Colorado Plateau, in Page, L. R., and others, compilers, Contributions to the geology of uranium and thorium by the United States Geological Survey and Atomic Energy Commission for the United Nations International Conference on peaceful uses of atomic energy, Geneva, Switzerland, 1955: U.S. Geol. Survey Prof. Paper 300, p. 195—201. B—8 Truesdell, A. H., and Weeks, A. D., 1959, Relation of the Todilto limestone uranium deposits to Colorado Plateau uranium deposits in sandstone [abs]: Geol. Soc. America Bull., v. 70, no. 12, pt. 2, p. 1689—1690. 4. 5h GEOLOGICAL SURVEY RESEARCH 1961 Wilpolt, R. H., and Wanek, A. A1, 1951, Geology of the region from Socorro and San Antonio east to Chupadera Mesa, Socorro County, New Mexico: U.S. Geol. Survey Oil and Gas Inv. Map OM—121.' ORIGIN OF URANIUM AND GOLD IN THE QUARTZ ITE-CONGLOMERATE OF THE SERRA DE JACOBINA, BRAZIL By MAX G. WHITE, Washington, D. C. The Serra de Jacobina is in the north-central part of the State of Bahia, northeast Brazil. It is a narrow prominent range that stands out in sharp relief over adjacent plains. The mountainous coun- try rises generally to altitudes of 600 to 800 meters with peaks of approximately 1,100 meters. The ad- jacent plains have an average altitude of about 450 meters. The principal town in the area is Jacobina, about 360 kilometers, by road, west of the port city of Salvador, Bahia. The gold deposits of the region have been known since the latter part of the 17th century. Lode and placer deposits have been mined on a small scale. Currently only the Canavieiras gold mine is operat- ing in the district. Uranium discovered in the pyritic gold ores of Jacobina in early 1954 (White, 1956) has been de- scribed in fair detail at the Canavieiras mine (White, 1957; Bateman, 1958). The gold-uranium mineral- ized quartzite-conglomerates have been traced in discontinuous outcrops from about 3 kilometers north of J acobina southward to the Rio do Almoco, a distance of 23 kilometers. The conglomerates are known to extend an additional 6 kilometers south- Ward into an area that has not yet been investigated for uranium. Fieldwork on the gold- and uranium-bearing con- glomerates at Morro do Vento, 2 kilometers south of the Canavieiras mine, constitutes the basis for the present report. GEOLOGIC SETTING AND STRUCTURE Rocks exposed in the Serra de J acobina (Branner, 1910) in the vicinity of the town of Jacobina con- sistvof White quartzite that in the upper part has some nonconglomeratic sandstone, and in the-lower part numerous conglomerate beds that contain py- ritic gold-uranium deposits. The conglomerates are restricted to the western flank of the Serra, Where On the eastern border of the Serra the White quart- zite is overlain by slate and phyllite. Scattered pock- quartzite. The rocks in the Serra «Ee J acobina dip easterly at ), and strike northerly, parallel to the trend of the range. Details of the structure are not well k own, but considering the width (6 km) of the Serr , any divergence in strike of the quartzite from the trend of the Serra would. at some short distance orth of Jacobina. Many high—angle faults cut th Serra de Jacobina and are fault blocks. The con‘ lomerates may have been removed by faulting nor h of Jacobina. In a few probably was an ultrama c rock (possibly pyroxen- ite) cut across the quartz teeconglomerate. N0 pre- but many of them lie in the north-trending faults. A similarity of these rockxls: and their ore deposits to Africa has been noted by} earlier writers (Oliveira and Leonardos, 1943). ‘ they lie in contact with weathered granitic rocks. ets of high-grade manganese oxides are found in the high angles (45° to 70 steep dip of the rocks End the relatively narrow carry the basal conglomeiate away from the Serra many of the morros (hill ) that make up the range places highly weathered ark-colored dikes of what ferred orientation of the dikes has been observed, the well-known gold-beari g conglomerates of South ORIGIN OF. DEPOSITS The uranium mineral in the Serra de Jacobina conglomerates has been i entified by X-ray diffrac- tion as uraninite. It occur in close association with gold and pyrite in silicifi d quartzite-conglomerate. The mineralized rock is gr en, owing to the presence of chrome-bearing mica, o brown to yellow owing to limonite formed from oxidation of pyrite. On Morros , do Vento, a mineralized zone 1,260 meters long has I l SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 an average content of 0.008 percent equivalent U308 and 10 grams of gold per metric ton of rock. This mineralized zone ranges from one-half to 10 meters in thickness but averages about 2 meters. The mineralized zone apparently parallels the strike of the enclosing sedimentary rocks and from place to place it consists of either conglomerate or quartz- ite. Numerous sections measured across the mineral- ized zone show that about 45 percent of the host rock is quartzite and the remaining 55 percent is conglomerate. The boundary of the mineralized rock at some places coincides with the edge of a con- glomerate lens or a quartzite bed, but at other places the boundaries are within lenses or beds having otherwise uniform lithology. Some mineralized zones or shoots that have well—defined boundaries transect both quartzite and conglomerate beds. It is apparent that the mineralization does not favor any lithologic unit in the quartzite-conglom- erate sequence. Moreover there seemingly is no cor- relation between high values of gold and uranium and any particular rock type. It would appear, there- fore, that this ore deposit is not a placer, which is the origin that has been suggested for the somewhat B—9 similar South African deposits, and for gold-bearing conglomerates of Blind River, Ontario (Davidson, 1957 ). Rather, the minerals probably were emplaced by hydrothermal solutions introduced along a pos- sible north-south fracture or fracture zone, appar- ently parallel to the bedding. This conclusion is strengthened by the presence of quartz stringers and veins and the extensive sericitization and chloriti- zation. REFERENCES Bateman, J. D., 1958, Uranium-bearing auriferous reefs at Jacobina, Brazil: Econ. Geology, v. 53, p. 417—425. Branner, J. C., 1910, The geology and topography of the Serra de Jacobina, State of Bahia, Brazil: Am. Jour. Science, 4th ser., v. 30, p. 385—392. Davidson, C. F., 1957, On the occurrence of uranium in ancient conglomerates: Econ. Geology v. 52, p. 668—693. Oliveira, A. 1., and Leonardos, 0. H., 1943, Geologia do Brazil, 2nd ed.: Ministerio da Agricultura, Rio de Janeiro. ' White, M. G., 1956, Uranium in the Serra de Jacobina, in Peaceful uses of atomic energy: Geneva, United Nations Internat. Conf. Proc., v. 6, p. 140—142. White, M. G., 1957, Uranium in the auriferous conglomerates at the Canavieiras gold mine, State of Bahia, Brazil: Engenharia, Mineracao e Metalurgia, v. 26, no. 155, Nov., p. 279—282. 5% HYDROLOGIC STUDIES 5. MAGNITUDE AND FREQUENCY OF FLOODS IN SUBURBAN AREAS By R. W. CARTER, Washington, D. C. The effect of suburban development on the mag— nitude of floods may be evaluated by examining the relations between floods of a given recurrence in- terval and the drainage area, lag time, and a length- slope parameter. Although these relations may not measure the effect as. precisely as would be possible With “before and after” records of rainfall and streamflow, they 'do permit fairly accurate predic- tion, using existing records, of the effect of suburban development upon flood peaks. Suburban development changes two of the basic elements that determine the magnitude and timing of the volume and peak of the flood hydrograph. The average infiltration rate is decreased because roof- tops and city streets are impervious. The lag time between rainfall excess and the flood hydrograph is decreased because of storm sewers and improve- ments to the principal stream channels. The net efi'ect of these changes on the magnitude and fre- quency of floods in the vicinity of Washington, DC, has been evaluated. The percentage of impervious surface area in basins in which suburban development is virtually complete is fairly low. For example, the percentages for Little Falls Branch near Bethesda, Md., and Four Mile Run near Alexandria, Va., based on aerial photographs taken in 1955, are 12.6 and 11.5, re- spectively. An approximation of the effect of im- pervious area on flood peaks is given by equation (1), which is based on the following assumptions: B—10 1. The average rainfall-runoff coefficient of 0.3 as determined from rainfall-flood volume studies for storms in the Washington, DC, area applies to flood peaks as well as to flood volumes. 2. The effect of the changes in impervious area is independent of the size of flood. 3. Seventy-five percent of the rainfall volume on impervious surfaces reaches the stream channel. 4. The impervious area consists of many fairly small areas randomly distributed throughout the basin. 0.30 + 0.0045 I ‘ 0.30 (1) In this equation K is the factor by which all flood peaks are increased by the percent of impervious K: area, I. For example, if 10 percent of the area is , impervious, the value of K is 1.15. The effect of imperviousness is small relative to other effects of suburban development on flood peaks. The average time interval, T, between the cen- troids of rainfall excess and of‘ the resulting flood hydrograph, was determined for each of 20 streams in the immediate vicinity of Washington, D. C. The time distribution of rainfall excess was determined from continuous records ‘of rainfall and time-infil- tration curves. The criteria for selection of storms were (a) a uniform areal distribution and (b) a short duration time relative to the lag time. In figure 5.1, lag times are shown as a function of L/ \/ S where L is the total length from the gaging point to the rim of the basin measured along the principal channel, and S is the weighted slope of an order of 3 or greater of all stream channels in the basin. The weighted slopes were computed as fol- lows: 2 2 S: [T— (Li/VS) ( ) Curve 1 on figure 5.1 is the relation for unde- veloped areas in the Piedmont province near Wash- ington, and may be expressed as L 0.6 Snyder (1958) found that a similar equation with different coefficients, but the same exponent, applied to areas in California, Virginia, and other states. The lower limit of the relation of lag time to L/VS is probably defined by curve 3 on figure 5.1, which is based on data given by Snyder for basins that are completely sewered and have no natural channels. (3) GEOLOGICAL SURVEY RESEARCH 1961 Values of lag time f r basins that are partly sewered, but with the rincipal stream channels maintained in their nat ral condition, should plot between curves 1 and 3. The points numbered 7, 10, 22, 23, and 24 on figure 5.1 are for such basins in thevicinity of Washington where suburban de- velopment is virtually complete. These points tend to define curVe 2 which can be expressed T: 1.20 (f—QO'6 The slopes of curves 2 and 3, figure 51, have been made identical to the slope of curve 1, although the slopes of the curves 2 and 3 are not well defined by available data. The effect of changes in lag time on the magnitude , and frequency of floods may be determined by a multiple regression technique. The magnitude of floods of a given recurrence interval for undeveloped basins is considered to be a function of T and A, Where A is the size of the drainage basin in square miles. Data for developed basins may also be used to determine this relation if the effect of impervious- ness on flood peaks is first accounted for, and if it is assumed that the effect of T and K are independent. Data for developed and undeveloped basins have thus been used to define an equation of the form, Q _ 7;— HAD (4) (5) The magnitude of the flood discharge a in cfs, which corresponds to a recurrence interval of 2.33 years, was determined for each of 18 streams from the record of maximum annual peak discharges. For each stream the annual peaks were plotted against the recurrence interval computed as (n + 1) /m where m is the order number and n is the number of years of record. The period 1951 to 1959 was used. The value of (3 for each stream was determined from the discharge-recurrence relation. The constants in the functional expression of equation (5) were defined by multiple regression using values of (5 and T computed from records for each stream and using the value of K from equation 1. The value of K from equation 1 was 1.00 for nine of the streams and ranged from 1.00 to 1.19. The equation of the regression is 9K: 223 140-85 11—0-45 (6) with a standard error of —22 and +29 percent. The value of the exponent of A is significant at the SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 LAG TIME, T, IN HOURS B—ll 0 Natural basins —0 ’z ’1’ ‘ OPartiallysewered _ owes , ’ ’ 0 Completely sewered I I I 011' llllllJl llllllJJ 11 ' 0.1 . 1 10 L/\/§,L IN MILES, S IN FEET PER MILE FIGURE 5.1.—Efi‘ect of suburban development on lag time. 99 percent confidence level; the value of the exponent of T at the 98 percent level. Data used to derive the equation include a range in A from 3.9 to 546 square miles, and a range in T from 1.2 to 18.6 hours. The effect of suburban developments on floods with a recurrence interval of 2.33 years may be evalu- ated by use of figure 5.1, and equations (1) and (6). For example, assume that the relation between T and L/VS changes the values given in curve 1 to the values given on curve 2 (fig. 5.1) because of suburban development, and that the percent im- 5% U (Suburban) 'Q (Undeveloped) perviousness is increased from 0 to 12 percent. Then (3.10 )0-45 (.354) = 1.8 1.20 .300_ The ratio 1.8 is believed to be the maximum effect of complete suburban development on flood peaks of any recurrence interval for drainage basins larger than 4 square miles in the Washington area. REFERENCE Snyder, Franklin E, 1958, Synthetic flood frequency: Am. Soc. Civil Engineers Proc. v. 84, no. HY5, 22 p. B—12 GEOLOGICAL SURVEY RESEARCH 1961 6. EFFECT OF ARTIFICIAL STORAGE ON PEAK FLOW By WILLIAM D. MITCHELL, Champaign, 111. As a supplement to the regular network of gaging stations, many districts now operate a network of high-water partial-record stations. Practical con- siderations have dictated that many of these be lo- cated at culverts, or other channel constrictions, at which the peak flows may be materially affected by artificial storage. To be of maximum value in regional flood studies, the recorded amounts of such peak flows shouldbe increased to account for ' the effect of artificial storage. The problem is com- plicated by the lack of complete hydrographs for most sites; only the peak stage and outflow dis- charge are observed for any given flood, therefore the usual methods of flood routing cannot be ap- plied. How, then, can an observed outflow peak be transformed to the corresponding inflow peak? Various arbitrary solutions have yielded highly varying results, leading to the conclusion that a satisfactory solution could be obtained only by making a tabulation of I /O (inflow peak divided by outflow peak) resulting from routing all possible inflow hydrographs through all possible reservoirs. Then, given an appropriate description of a specific inflow hydrograph and specific reservoir, the tabu- lations would provide the appropriate correction factor. Obviously, it would be impractical to route an infinite number of hydrographs through an in- finite number of reservoirs, but it appeared feasible . to make detailed studies of a few combinations, and ‘ arrange the results in such manner that interpola- tions might be made for others. It is possible to make such interpolations if inflow hydrographs and storage-outflow relations are reduced to dimension- less bases. ' Inflow hydrographs may be described in terms of Q, the instantaneousdischarge, and H, the time from beginning of rainfall excess, and it is postu- lated that Q is determined by H; A, the size of the drainage area; Po, the amount of rainfall excess; D, the duration of the rainfall excess; and T and k, characteristic times for a given drainage basin that indicate the time lag between rainfall and runoff. These factors are combined into the dimensionless ratios (QT/APc), (H/T), (lo/T), and (D/T), lead- ing to families of inflow hydrographs in which the first ratio is the ordinate, the second is the abscissa, and the third and fourth are distinguishing param- eters. Reservoir routing requires an expression of the form S 2 K0”, in which S is the storage, K is a con- stant depending upon the relative capacities of the reservoir and the outlet, 0 is the outflow, and 90 de- pends on the relative slopes of the stage-discharge and stage—storage curves. The minimum value of x ’ is 0.67 which would apply only to outflow at critical depth from a reservoir with vertical sides. The maximum 9c is indeterminate, but for many sites its value appears to be near 1; in fact, it is a common assumption in many reservoir problems that S = K0, and the storage is said to be linear. (Preliminary studies indicate that the methods here described may be expanded to include nonlinear storage, but the present analysis treats only linear storage.) In the expression S 2 KO, K has the dimension of time, and is reduced to a dimensionless base by dividing by T. Sixteen dimensionless inflow hydrographs were routed through varying degrees of linear storage to obtain 128 outflow hydrographs. From these rout- ings, pertinent tabulations were prepared as shown on table 1. On the first line, K/ T = 0, so that the data are for the inflow hydrograph. Other lines are for outflow hydrographs, with K/T increasing to 2.0. The three central columns of the table repre- sent, respectively, the time of occurrence of the peak, the magnitude of the peak, and the time of passage of the centroid of volume. The ratio for time of travel through the reservoir, t,./ T, may be obtained by subtracting value of t,./T for K/T = 0 from other values of t,,/ T. TABLE 1.——Results of routing inflow hydrographs through linear storage [k/T : 1.0; D/T = 0.1] K/T tp/T QT/APe WIT I/0 0.0 ...... 0.88 443.0 1.264 ............ .1 ...... .98 420.0 1.369 1.031 .3 ...... 1.16 359.6 1.588 1.204 .5 ...... 1.30 309.4 1.790 1.399 .7 ...... 1.44 272.4 1.977 1.590 1.0 ...... 1.60 232.4 2.237 1.863 1.5 ...... 1.80 188.5 2.636 2.297 2.0 ...... 1.96 159.6 3.012 2.713 The data may be arranged in several ways, but the most convenient arrangement appears to be that SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B-13 3.8 3.4 - 3.0 — 2.6 —'- l/O ‘— 2.2 +— 1.4 >— 1.0 1 I I l 1 k/T J l l l L l 0 .10 .20 .30 .40 .50 .60 tr/’fv FIGURE 6.1.——I/O as a function of tr, t1), and k/T. shown as figure 6.1, in which [/0 is plotted as ordi- nate against tr/tv as abscissa for different values of k/ T. Analysis of the tabulated data indicates that, for purposes of this plot, the ratio t,/ t., should be computed by the formula: t,./tv = 0.9 K/T/(1.00 + 0.7 D/T + 0.9 K/T) Not all of the points plotted fit the curves per- fectly, but only 2 of the 128 values are more than 10 percent from the curve, and these are for extreme conditions. (Both are for k/T = 0.3, D/T = 1.5; for K/T = 1.5, the error is 11.5 percent; for K/T = 2.0, 12.0 percent.) Two-thirds of the true values are within about 3 percent of the curve values. B-14 To use figure 6.1, it is necessary to have values for D, K, T, and k. Values of D may be estimated from rainfall records, and K may be estimated from the storage-outflow curve. Work is continuing, as a part of another project, from which it is hoped to derive methods of estimating T and 15 from the physiographic characteristics of the drainage area. 5% GEOLOGICAL SURVEY RESEARCH 1961 Until these methods become available, it is suggested that T may be computed by one of the several for- mulas now available for Computing time of concen- tration; values of k/ T may be estimated from the steepness of the recession curve of surface runoff, using 0.3 for very rapid recession, 1.5 for very slow recession, and 0.7 for average recession. 7. DISTINCTIVE CHARACTERISTICS OF GLACIER RUNOFF By MARK F. MEIER and WENDELL V. TANGBORN, Tacoma, Wash. Salient features of glacier runoff patterns may be brought out by comparing runoff data from two glacier-covered basins with data from three moun- tain basins that do not retain any significant snow- fields throughout most years. These comparisons also show the influence of climatic factors, such as precipitation, on the runoff. Most American glaciers behave as natural storage reservoirs that retain a predominant portion of the yearly total precipitation during a winter period of high precipitation, and release large quantities of water during a summer period of high temperatures and low precipitation. Thus, the annual variation of runoff from glacier-covered basins bears little or no relation to the annual variation of precipitation. This behavior is typical of all mountain drainage basins in areas of heavy snowfall, but the effect is most extreme for glacier-covered basins. The distributions within a water year of runoff, precipitation, and degree-days for selected basins in Washington and Montana are shown in figure 7.1. The four basins in Washington are on the western slope of the Northern Cascade Mountains and in- clude basins that are in both the non-glacier-covered foothills and on the largely glacier-covered crest of the range (table 1). Runoff and precipitation pat- terns from a different climatic environment are shown for. a partly glacier-covered basin in the Northern Rocky Mountains of Montana. The data used in plotting the precipitation curves were not obtained from stations located within these basins but from selected Weather Bureau stations that are believed to have similar annual precipitation dis- tributions. These curves clearly demonstrate the long lag between precipitation and runoff that is characteris- tic of glacier-covered terrain. The curves from in- termediate basins show that, as the mean elevation and amount of glacier-cover increases, appreciable runoff is delayed until later in the water year, and in a largely glacier—covered basin the highest monthly runoff occurs in July or August. The role of the various solar and atmospheric energy sources in the production of meltwater runoff from either type basin is not developed in this article. However, there is an obvious qualitative relation between air temperature and runoff for a glacier-covered basin. This is shown by the cumu- lative degree-days above 32°F and runoff measured at the outlet of the Grinnell Creek basin (fig. 7.1). Pronounced diurnal fluctuations in discharge are characteristic of the runoff from glacier-covered basins, reflecting diurnal fluctuations in the energy supplied for melting ice. Average daily curves of icemelt and runoff during clear weather are shown in figure 7.2 for the South Fork Cascade River basin. The asymmetric nature of the melting curve is due to a slow morning rise of incident solar radiation, caused by the basin’s high eastern rim and a north- westerly slope of the ice surface. This condition occurs over about half of the basin area. The total daily runoff is less than the indicated daily icemelt because the icemelt recorder was located in a re- gion of higher-than-average melt rates. At this time of the year the mean time of transit of meltwater from its point of generation to the gaging station at the outlet was of the order of magnitude of 4 hours. In general, a thick, complete snowpack stores rainfall, releasing it gradually or retaining it as ice, Whereas a bare ice or firm surface permits rapid 100 r . . v . . v . . . v . v v . r u r /- I, [I 90 _ . .___,/ ’1 / / I/ 8 - - i 0 / , / 1 I, 70 - . / 5 , ,, l E b c , I 60 - / '3‘; d e / 9 l/h Lu / l 50 — ~ — / / _ g I : ,l < ' I 5‘ 40 ‘ / / E I 3 ' / o / // 30 - - ‘ / / / x 20 > ‘ / /’ ___—._—_..—_ . I, 10 . . _ / ____________ ” / 1””, z 0 . r . . . . r i . . r . 1 . . . . Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar Apr. May June July Aug. Sept. MONTH MONTH FIGURE 7.1.—Cumulative runofl’ and precipitation for selected drainage basins in the Northern Cascade Mountains, Wash., and the Northern Rocky Mountains, Mont. 11, Average precipitation at Darrington, Diablo Dam, and Sedro Woolley, Wash. b, Runoff of Day Creek near Lyman, Wash. 6, Runoff of South Fork Nooksack River near Wickersham, Wash. d, Runofl" of Stetattle Creek near Newhalem, Wash. runoff of rainfall and produces a “flashy” hydro- graph. The effect of individual rain or snow storms on the runoff hydrograph is shown in figure 7.3. In- spection of these data shows that it is very difficult to forecast runoff from a given rainstorm. The rate of runoff following a rainstorm depends on (a) the amount of basin area covered with snow, (b) the e, Runoff of South Fork Cascade River at South Cascade Glacier, Wash. f, Precipitation at Summit, Mont. g, Runoff of Grinnell Creek near Many Glacier, Mont. h,Degree-days above 32°F at Grinnell Creek near Many Glacier, Mont. thickness and density of the snowpack, (c) snow temperature, ((1) whether the snow has been chan- neled by previous rain or periods of high melt rate, and (e) perhaps other factors. These factors show a normal seasonal variation, but may change rapidly and unpredictably in the fall. Perhaps the most distinctive aspect of glacier hydrology is the natural change in ice storage from TABLE 1.—Chamcteristics of drainage basins Water Altitude Drainage Percent Total Basin year area of area yearly Physiographic description Mean Maximum (square glacier- runoff (feet) (feet) miles) covered (inches) Day Creek near Lyman, Wash.. . . . . . , . 1959 2,310 4,311 36.3 0 121 Low altitude forested foothills and low mountains. South Fork Nooksack River near 1959 3,000 6,400 103 0 120 Forested foothills and few high Wickersham, Wash. _ peaks. Stetattle Creek near Newhalem, Wash . . 1959 5,000 7,200 21 . 4 2 155 Forested valleys and high peaks near crest of range. South Fork Cascade River at South 1959 6,440 8,265 2.39 61 191 Bare slopes, jagged high peaks, Cascade Glacier, Wash. little vegetation. Grinnell Creek near Many Glacier, 1960 6, 780 9,541 3 . 47 14 93 Bare slopes, jagged high peaks, Mont. some vegetation. B—16 .020 [- / RATE OF MELT 0R RUNOFF, IN FEET PER HOUR 12 Noon Midnight TIME FIGURE 7.2.—Mean diurnal variation in rates of icemelt and runoff for 14 days of clear, warm weather occurring dur- ing period July 13—30, 1958. Icemelt was measured at station A, elevation 5,527 feet, on South Cascade Glacier. Runoff was measured at South Fork Cascade River at South Cascade Glacier, Wash., and was averaged over the total area of ice and snow in the drainage basin. GEOLOGICAL SURVEY RESEARCH 1961 year to year. The storage changes tend to counter- act the effects of cool wet, or warm dry years, as shown by table 2, which presents data from South Fork Cascade River during two contrasting years. Departures from long-term means of temperature and precipitation are reported for Newhalem, the nearest station for which these data are available. Loss of water through evaporation was found by our measurements to be negligible during the summer, and measurements on other glaciers have shown this to be generally true during the whole year. Thus, changes in the mass of a glacier represent true addi- tions to, or withdrawals from, ice storage. TABLE 2.—Water budget for South Fork Cascade River at South Cascade Glacier, Wash., for two contrasting years South Fork Cascade River at South Cascade Glacier, Wash. Newhalem, Wash. Water Change in Precipitation Temperature year Precipitation 1 Runoff 2 storage 2 departure 3 departure 3 (inches) (inches) (inches) (inches) (°F.) 1958.... 4130 4200 1 —5l ~14.2 +3.0 1959.. . , 210 191 +17 +325 —0.8 1 As measured at P1, 6,160 feet elevation, on South Cascade Glacier. 2 Average values for whole drainage basin. 3 Departures from 1931—55 means, by U.S. Weather Bureau. 4 Part of the record estimated. ,_ \u w 150~ , 52 => 100 °§ Eu: 8; 50» 5 /Dashed where estimated Runoff 1A 5 » 0» ---------------- ~~~~~ / . . . ‘2 5 a :3 3 1 <5 241W Precipitation ,_ ,_ 11. 1.. l ””1 . 1 l _— 1 1 g E; 01 111.1111}; 1‘1} NHL 1J1 kiwi on L y1,1,nlhl1laT 1 i 5 3 a. De thoisnow ,_ ,1 //’_’ 20 g E :3 Snow- lree ground 9 Snow- free groundy/ JILJ 115 E E Um 5 g 20 If [1.46935th where estimated . 1‘0 2 ; It: L r . .1/. , o — g2 10 " ’ :L,//T15I E g‘ 0 . r . *7" "Th. 0% o "’ E60 3: 1 “E 50 Temperature W \P/\ or“ 1 2:“) /\ mm A . A/l. AA. M A11 1 §5301 v VWW M VM W l “”20 Q4“ 2N wmlo i v—o m 1 7 1.1.1 , 1 1 ,, 1 1 1,1111 1 1 1 11 1 a 0 Oct. Nov. T Dec I Jan 1 Feb 1 Mar Apr. 1 May 1 June 1 July T Aug. 1' Sept. 1 FIGURE 7.3.—-—Variation of runoff, precipitation, snow depth, percent of snow-free ground, and temperature for the drainage basin of South Fork Cascade River at South Cascade Glacier, Wash., during the 1960 water year. Dashed lines indicate periods of estimated record. Precipitation distribution during the period October 1, 1959, to April 3, 1960, and at several later short intervals was computed on basis of known total precipitation on South Cascade Glacier at P1 (6,160 feet) and known daily precipitation values at Darrington, Wash. Precipitation is differentiated into rain (solid black bars), mixed rain and snow (dotted bars), or snow (clear bars), on basis of free-air freezing levels over Seattle or actual observa- tion. Snow depths were measured at P1 (6,160 feet). Temperature record is a composite of Darrington daily means minus 16°F (lapse-rate correction) shown by light lines, or actual measurement at research station at South Cascade Glacier (elevation 6,040 feet) shown by heavy lines. 5? SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—17 8. RECENT HYDROLOGIC TRENDS IN THE PACIFIC NORTHWEST By WILBUR D. SIMONs, Tacoma, Wash. Annual runoff and annual precipitation in the Columbia River basin decreased, and annual mean temperature gradually increased between 1885 and 1945, according to an analysis by McDonald and Langbein (1948). To determine if these trends have continued, data for runoff, precipitation, and tem- peratures have been examined for the period 1885 to 1960—15 more years of record than was available to McDonald and Langbein. Annual deviations from the 1911—60 means were weighted for running 5- year periods according to the formula: a+2b+3c+2d+e - 9 in which a, b, . . . are data for consecutive years, and the deviations were plotted against the middle year. The period 1911—60 was chosen as a reference be- cause it was the longest period of concurrent records. In this preliminary analysis no adjustments of run- off were made for irrigation diversions or other modifications caused by the works of man. +21, __ _2° 1 Trend curves of annual streamflow for seven index stations are shown on figure 8.2. A distinct down- ward trend for the years prior to 1940 and an up- trend during succeeding years are evident. At 5 of the stations shown the 15-year average for the period 1946—60 was the maximum 15-year average of record, being surpassed only at those stations that had records during the 1890’s. The flow of the Columbia River near The Dalles, 0reg., without con- sidering the changes in flow regimen caused by the works of man, was only 7 percent less during the period 1946—60 than during the period 1891—1905. Annual precipitation might be expected to show trends similar to those exhibited by streamflow data. Trend curves for five precipitation stations are shown on figure 8.3. An upward trend during the past 15 years is discernible in three of the five sta- tions studied but at only one station is the precipi- tation greater during the past 15 years than during the late 1800’s. The trends in annual precipitation +2~ o l + N o WEIGHTED DEVIATIONS + "3 I o l -2 1880 1890 V 1900 1910 Seattle, Wash. 1 l l” Missoula, Mont. l I Spokane, Wash. 1 I l l | 1920 1930 1940 1950 1960 Portland, Oreg. FIGURE 8.1.—Weighted deviations, in degrees Fahrenheit, from 1911—60 average annual temperatures at selected stations in the Pacific Northwest. B—18 +20— +20»— +20— —20 +20~ _20._ WEIGHTED PERCENTAGE DEVIATIONS +20— —201— +20— —20 +20r — 20 1 880 1890 GEOLOGICAL SURVEY RESEARCH 1961 l I L l Pend Oreille River at Z Canyon near Metaline Falls, Wash. ! ' L J Spokane River at Spokane, Wash. 1 I l J Kootenay River at Libby, Monti WW Similkameen River near Nighthawk, Wash. l l I 1 l Chelan River at Chelan, Wash 1 l J Deschutes River near Biggs, Oreg. I | | | l 1900 1910 1920 1930 1940 1950 1960 Columbia River near The Dalles, Oreg. FIGURE 8.2.—Weighted percentage deviations from 1911—60 average annual precipitation at selected stations in the Pacific Northwest. ‘—A_A r—k +20 —20 +201. -20.— +20r— —20 WElGHTED PERCENTAGE DEVIATlONS +201— _20 +40 +20 — 20 1 880 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—19 l L l Walla Walla, Wash. I l J Spokane, Wash. Boise, Ida. 1 1890 l 1900 | 1910 l Missoula, Mont. l l l J 1920 1930 1940 1950 1960 Portland, Oreg. FIGURE 8.3.——Weighted percentage deviations from 1911—60 average discharges at selected gaging stations in the Columbia River basin. B—ZO are similar to the trends in annual runoff but are less clearly defined. Trend curves for four temperature stations are shown on figure 8.1. Earlier records indicated a gradual rising temperature that reached a maximum about 1940. A downward trend since then is quite pronounced at each of the stations for which records were studied. However, at only one station do the recent temperatures reach the lower temperatures of the 1890’s. The general tendency is for hot and dry years or wet and cool years to coincide. i GEOLOGICAL sURVEY RESEARCH 1961 Thus the analysis of data for the total 75-year period shows significant changes in trends and demonstates the necessity for continuing data col- lection and analysis in order to provide reliable in- formation for development and evaluation of water- use projects. REFERENCE McDonald, C. C., and Langbein, Walter, 1948, Trends in run- off: Am. Geophys. Union Trans., v. 29, no. 3, p. 387—397. ’5? 9. PRECIPITATION AS A VARIABLE IN THE CORRELATION OF RUNOFF DATA By WILLIAM J. SCHNEIDER, Washington, D. C. Differences in runoff between basins are at least partly caused by differences in precipitation. Pre- cipitation data, therefore, should be useful in im- proving the correlation between runoffs from differ- ent basins. The effect of differences in precipitation on cor- relation of runoff can be expressed by either of two equations: Rn 2 “Bo AP) (1) Rn : f(R(‘ (adJ)) (2) in which R1, is the runoff of the dependent basin, Ric is the runoff of the control basin, AP is a measure of difference in precipitation between basins, and Rp(adj) is the runoff of the control basin adjusted for differences in precipitation between basins. Investigations to date indicate that a logarithmic transformation of runoff data is necessary to obtain an essentially homoscedastic variance. The model equations using transformed runoff variables are: (1a) (2a) The term AP in equation (1a) may be obtained by using precipitation for either basin as the subtrahend in obtaining the difference in precipitation. Use of precipitation data for the dependent basin as the subtrahend will give a positive coefficient for b; use of precipitation data for the control basin as the subtrahend will give a negative coefficient. 10g RD 2 a. + I), log R0 + bgAP log R,, = a + I), log R" (adj) In equation (2a) the adjusted runoff for the con— trol basin is obtained as follows. The precipitation- runoff relation for the control basin is developed from the existing data. From this relation, two expected values of runoff (RH, and Rm) are deter— mined. The first, (an), is the expected value based on the precipitation for the dependent area, the second, (Rm), is the expected value based on the precipitation for the control area. The difference (Rm—RM) represents the expected difference in runoff from the control basin due to the difference in precipitation (ARP), taking into account the mag- nitude of the precipitation. This difference in run- off is then added to the measured runoff to give Ra (adj) 2 Ho + ARI’ (3) which is then correlated directly with the runoff from the dependent basin. A moderately extreme example of the effect of precipitation differences on the runoff relation be- tween two basins is shown in the following results. Correlation of annual runoff of Albright Creek at East Homer, N. Y., (drainage area, 7.08 square miles) with runoff of SOS Watershed 97 at Coshoc- ton, Ohio, (drainage area, 7.16 square miles) for the 15-year period 1941—55 gave a correlation coeffi- cient of 0.47 and a standard error of estimate of +43 and —30 percent, based on the Coshocton area as the dependent variable. The inclusion of precipita- tion data in the form of AP as shown in equation SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 (1a) reduced the standard error of estimate to +15 and —13 percent, and resulted in a correlation coeffi- 'cient of 0.93. Thus, the inclusion of AP accounted for an additional 64 percent of the variance in the data, reducing the residual variance from 78 to 14 percent. The use of adjusted runoff as indicated in equation (2a) reduced the standard error of estimate to +14 and —13 percent, and resulted in a correla- tion coefficient of 0.95. All regression coefficients were highly significant in both equations. Improvement in determining runoff relations can also be demonstrated for basins that are close to- gether. The areas drained by Sage Brook near South Berlin, N.Y., (drainage area, 0.70 square miles) and by Cold Spring Brook at China, N. Y., (drainage B—21 area, 1.51 square miles) are less than 25 miles apart. The correlation coefficient between annual runoffs for the 22-year period 1936—57 is 0.87 and the stand- ard error of estimate for Sage Brook is +12 and —11 percent: Including precipitation data as de- scribed in equation (1a) reduced the standard error of estimate to +8 and —7 percent, and resulted in a correlation coefl‘lcient of 0.92. Model equation (2a) gave similar results. Although the models used are considered satisfac- tory, it is not implied that they are the best ones for estimating runoff. The two examples are cited above merely to illustrate the feasibility of improving a determination of the relation between runoffs by considering differences in precipitation. 5% 10. REGIONAL LOW FLOW FREQUENCY ANALYSIS By H. C. RIGGS, Washington, D. C. The distribution of the population of annual minimum flows at a stream site would be useful in planning the optimum development of the flow. In hydrology the distribution of the population is never known; it can only be estimated from the data ob- tained at the site. The sample distribution so ob- tained may be considerably different from the populatiOn distribution; therefore some method is sought for obtaining a better estimate of the popu- lation distribution. The shape and position of a frequency curve (which is the sample distribution) of annual mini- . mum flows based on observational data at one site differ from those of a curve for another site be- cause of differences in physical characteristics of the basins and because of differences in weather ex- perienced. Examples are shown on figure 10.1. Both curves differ from their respective population curves because of the short periods of weather sampled. It is postulated that weather samples differ areally within a common time period. Therefore, some method of combining the experience at several sta- tions while maintaining the characteristics of each individual station record should result in better esti- mates of the frequency distributions. Such a method is called a regional analysis. Regional analysis is useful only when the correla- tion coefficient between minimum flows at two sta- tions is less than 1, but greater than some minimum value. Remembering that the purpose of regional analysis is to reduce sampling error in the frequency curve, it can be seen that flows which are completely correlated must also have the same sampling error and, therefore, combining the experience cannot re- duce this sampling error. Now consider the other extreme of poor correlation between flows. Poor correlation might indicate that different weather samples were experienced at different basins, or that the reactions to a particular weather occurrence were different, or both. The last is the most likely. Here, the combined experience averages deviations that consist both of sampling errors and of effects of differences in basin characteristics. Averaging Values of the latter component ordinarily " will not improve the estimate of the frequency curve; it may even produce an estimate of reduced reliability. Between total correlation and some minimum value of correlation is a range in which there is an op- portunity for reducing individual sampling errors (some of which are assumed to. be plus and some minus). This may be done by (a) relating the mag- nitude of the annual minimum flow at a certain B—22 300 O\° 0.0‘00 o 0% l o o o °‘°—-o o 100 I \o \ Buffalo River near Flat Woods \0 Drainage area=447 sq. mi. 0 a \ LL 9 o a 10 \o. 0‘ o\ _J u. O‘Q 2 0 o :> o o E \ 2 ° 0 E Harpeth River at Belleview\ _, Drainage area:404 sq. mi. °\ < 2 ° 0 z E °\. 0 1 \>—\o O O 0_1 I l I I I | I l I I; J 1.1 1.5 2 4 6 8 10 20 4O RECURRENCE INTERVAL (YEARS) FIGURE 10.1.—Frequency curves of two Tennessee streams. recurrence interval to the median annual minimum flow and to indexes which describe the differences in basin characteristics, and then (b) using the com- puted value rather than the value obtained from the frequency curve. The method of regional analysis just described is applied to frequency curves of annual minimum 7- day average flows for 47 sites in the regions, roughly, of New England, Georgia, and Kansas. The de- pendent variable is on, the discharge at 20-year re- currence interval from the frequency curve based on observations. The median annual minimum, Q, is also taken from the frequency curve. The effects of basin characteristics are described by drainage area (A) and by an index (S) of the slope of the base- flow recession curve, which is defined as the ratio (expressed as a percentage) of two discharges from the recession curve; the denominator of the ratio is Qz and the numerator is the discharge 10 days after the Q2 discharge. The index S describes the inte- grated effect of geology, topography, vegetal cover, and to some extent climate, 0n the minimum flows. GEOLOGICAL SURVEY RESEARCH 1961 The computed regression is— 10g Q20 = —2.58 + 1.13 log Q2 —0.22 log A + 1.3510g S + 0.09 (log Q2) [log (A/Q2)] The standard error of Q20 is —20 percent and +25 percent. The regression coefficient for the last term is statistically significant at the 5-percent level. All others are highly significant. Streams used in de- fining the equation have the following ranges of variables: 1.05 < Q2 < 1,770 cfs 4.12 < A < 11,220 sq mi 6.7 < S < 94 percent The equation was solved for Q20 for each of the 47 sites and for 61 additional: 25 in Tennessee, 4 in California and Washington, 24 in North Carolina, and 8 in Turkey. The computed value of Q20 for each of the 108 sites is plotted against the corresponding value obtained from the individual frequency curve on figure 10.2. No geographical bias is apparent from study of the deviations. The wide range in magnitude of Q20 and the Wide geographic range encompassed indicate that the relation should hold wherever (a) the rate of summer—and-fall base-flow recession is consistent from year to year and (b) the annual minimum flow occurs in the late summer or fall. 1000 100 g!“ vi ./ ‘2' ._. 020 FROM FREQUENCY CURVE (CFS) \ /- 0.01 0.01 0.1 1 10 100 1000 Q20 FROM REGIONAL EQUATION (CFS) FIGURE 10.2.—Comparison of Q... from the individual frequency curve with the corresponding Q20 from the regional equation. 5 l_r 1 v—V "f—fivri—Y—Y ’—P_ P Y 1' L 7 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 The reliability of the regionalized values of Q20 is directly related to the proportion of the regression error that is sampling error, and to the reliability of Q2. These two factors cannot be assessed at this B—23 time. However, the standard error of 25 percent does not seem excessive when one considers that there is some minimum sampling error below which no advantage would be gained by a regional analysis. 6% 11. MODIFIED CONVEYANCE-SLOPE APPLIED TO DEVELOPMENT OF STAGE-FALL-DISCHARGE RATINGS By WILLIAM C. GRIFFIN, Washington, D. C. The common gaging-station rating is a relation be- tween discharge and gage height. Ratings for gaging stations on streams with variable backwater effect must include an additional variable, fall (F), which is the difference in water-surface elevation at the ends of a reach of channel. Such ratings are called stage-fall-discharge ratings. All methods in general use for development of stage-fall-discharge ratings require trial and error solutions. This paper pre- sents a direct approach. In the Manning formula, Q 2 Big AR2/3SI/2, Q is discharge in cubic feet per second; n is a rough- ness factor; A is cross-sectional area; B is hydraulic radius; and S is energy slope. The term #ARW3 is commonly called conveyance, K. Thus, the for- mula reduces simply to Q = KVS. (1) A curve of conveyance against stage could be de- veloped from an instrument survey, and inasmuch as Q and K have the same units of cubic feet per second (slope is dimensionless), the stage-convey- ance curve could be used as the base stage-discharge rating. The only additional requirement for a com- plete rating is a relation for determining VS. Intui- tively, fall is the most logical factor to use in a rela- tion curve to yield \/S. If values of square root of slope as computed from the ratio of measured dis- charge to conveyance, when plotted against fall, de- fine a satisfactory curve of relation, the rating process is complete. ’ An example is given below for the Ohio River at Cincinnati, Ohio. Data were not available for ac- curately defining a conveyance curve, but discharge measurements provided sufficient information, ex- cept for the roughness factor, n, for a fair approxi- mation of conveyance at the measuring section. A value of 0.03 was selected for n; conveyance was computed for each of a sequence of discharge meas- urements ; and the relation between conveyance and discharge was defined graphically (fig. 11.1). It was postulated that the shape of the conveyance curve would be more important than its position. Hence, an error in n would be critical only if instead of being constant as was assumed, n should have varied with stage. The square root of energy slope was computed for each measurement, by dividing measured discharge by conveyance, and plotted against fall to define the right-hand curve of figure 11.1. This curve can be used in combination with the conveyance curve as the stage-faIl-discharge rating for the station. To use the rating, if gage height and fall are given, conveyance and \/ S can be obtained from the curves and the corresponding discharge is the product of these two. The rating just described is Virtually the same as the conventional constant-fall type of rating for variable backwater effect. This similarity would be more readily apparent if, for this particular station, equation 1 were modified as follows: Q = 0.01 K(100 VS). The advantage of the procedure described, then, is not that a new type of rating can be developed, but that a direct approach can be used to get a result that might never be apparent if an indirect method is attempted. The fact that a workable relation was developed without the use of trial and error procedure probably means that there was no significant variation of n with stage. Any error that may have been made in the choice of 0.03 for n would have been compen- sated for in the computed values of VS. B—24 GEOLOGICAL SURVEY RESEARCH 1961 55 I l T l l 50 — ._ 45— _ 40—— _l M 35 - — .012 . LIJ A D. E 9 E (I) V30— -I .010 > I— o (D [I I Lu 9 Z LIJ ‘ . LIJ I 25 — — .008 E IEIDJ‘, O I— 5 o O O 20— — .006 ‘1’ “J D: < D O‘ 15 “ —* .004 <0 D LIJ I- D 0. 10+— — .002 5 O O 5 —- _ FALL, IN FEET 0 1 2 3 4 5 o l I I I I I I I I I I I » I 0 5 10 15 20 25 30 35 40 45 CONVEYANCE (MILLIONS OF CUBIC FEET PER SECOND) FIGURE 11.1.—Stage-fall-conveyance relation for the Ohio River at Cincinnati, Ohio. ‘One recognized limitation in the use of the modi- fied conveyance-slope procedure for variable back- water ratings is at stations of the limiting-fall type, where backwater is not'present all the time. A characteristic of stations of this type is that, for a given stage, discharge reaches a maximum rate at some amount of fall and does not increase with in- creasing fall. At such stations the modified con- veyance-slope procedure would be applicable only for falls less than the limiting values, and it would be necessary to use the type of limiting-fall curve described by Mitchell (1954, p. 145) as the upper limit of discharge unaffected by variable backwater. Doubtless, other limitations will come to light as additional applications are made; their recognition will aid in delineating the conditions under which the method can be used to advantage. REFERENCE Mitchell, W. Div, 1954, Stage-fall-discharge relations for steady flow in prismatic channels: U.S. Geol. Survey Water- Supply Paper 1164, 162 p. 6% SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—25 12. FLOW IN AN ARTIFICIALLY ROUGHENED CHANNEL By H. J. KOLOSEUS and JACOB DAVIDIAN, Iowa City, Iowa Work done in cooperation with the Iowa Institute of Hydraulic Research A resistance coefficient, such as the Darcy-Weis- bach f or the Manning 12, is frequently used to eval- uate the energy losses due to the retarding effect of channel surfaces on a moving fluid. The coefficient is assumed to be a function of the relative rough- ness, the shape of the channel, and the Reynolds and Froude numbers; however, the relationship has not been defined for most cases of open-channel flow. Hence, the resistance coefficient is estimated on the basis of judgment and experience. As a first step toward a more rational determi- nation of the resistance coefficient, a laboratory study of the effect of roughness concentration on open- channel flow was undertaken. The roughness ele- ments, 3/16-inch metal cubes, were arranged in dia- mond patterns commensurate in size with particular roughness concentrations. The upstream face of each cube was placed normal to the mean direction of fluid motion. Tests were conducted in two rectangu- lar tiltable flumes, one 2 feet wide and 30 feet long, and the other 2.5 feet wide and 85 feet long. The experimental program was designed to maxi- mize the relative importance of the roughness in- fluence. Koloseus (1958, Ph. D. Thesis Iowa State University) has previously shown for supercritical flow that the resistance coefficient for a rough chan- nel of this type is independent of gravitational ef- fects when the Froude number is less than 1.6, and is independent of viscous effects when V f R k/4h ex- ceeds 600. Within these limitations, it is assumed that f is a function of the relative height and the cube concentration; that is = G(lc/4h, A)’ ‘ (1) where f is the resistance coefl‘icient, SghS/Vz; G means “function of” ; g is the acceleration of gravity; h is depth of flow; S is the energy gradient; V is the average velocity; It is height of roughness (lo/4h is called the relative height of roughness) ; A is rough- ness concentration, denoting the ratio of the total projected area of the roughness in the direction of mean fluid movement to the total floor area; B is Reynolds number, 4Vh/y; and v is kinematic vis- cosity. Experimental data plotted on figure 12.1 define the relation 1 __ I —09 l 2 Vf 210g 0.14 A (4h/k) ( ) The scatter of values about the line for equation (2) (fig. 12.1) is remarkably small over 4—fold variation in k/4h and the 64-fold variation in A. Equation (2) reduces to that of N ikuradse (1933) for flow in sand-roughened pipes when the rough- ness-concentration factor is ignored. Comparable changes in magnitude of either k/4h or A have ap- proximately the same effect on the resistance coeffi- cient. As with relative height, the roughness con- go 6.5 ‘ oo o/" 6.0 77-7 7- V,gi,,,_fli, 1, W a / - 7 4' - 5.5 ——~ “""fl‘fi' 77* 11,1 g_./,i 7 ./c _L :3 7f— 5.o — 1 ~— :9: M V 86 9‘9 | 83999 4.5 896%» V 1,, «7 j ------- e):— 963/ 4.0 “/77 ,1 W » VAS :z 3,5 ~77 547~~ _, ._, ~— —-~«~ V‘- ' EXPLANATION 9 ° x ‘ 33.". * Syrgbol 1/512 " T’ . 1/128 3‘0 a” a 1/32 A 'u' a 1/8 . / , l ;2.5 . 1 , . 20 ‘40 60 100 200 4006001000 2000 0.14/\~°-9(4h/k) ’ FIGURE 12.1.—Variation of the resistance coefficient with the relative height and the roughness concentration. B—26 centration must be more than doubled in order to obtain a two-fold increase in the resistance co- eflicient. GEOLOGICAL SURVEY RESEARCH 1961 REFERENCE Nikuradse, J., 1933, Stromungsgesetze in rauhen Rohren: Verein Deutscher Ingenieure, Forschungsheft 361. 61‘ 13. DIMENSIONS OF SOME STABLE ALLUVIAL CHANNELS By S. A. SCHUMM, Denver, Colo. Several attempts have been made to develop a series of equations that can be used to calculate the dimensions of stable alluvial channels (Leliavsky, 1955). During recent investigations into the mor- phology of streams in a semiarid environment, in- formation was collected that may have a practical application in the solution of such problems. This information indicates that the shape of alluvial chan- nels and the stratification of channel deposits are significantly related to the type of sediment found within these channels (Schumm, 1960a, 1960b). In this analysis the silt-clay content of alluvium is used as a simple but significant parameter for sedi- ment description. Silt-clay as discussed here is sedi- ment that passed a ZOO—mesh sieve or that is smaller than 0.074 mm. The percentage of silt and clay in a sample gives an indication of the physical properties of the sediment, for as the silt-clay fraction increases, cohesiveness of the sediment increases, permeability decreases (Burmister, 1952, p. 20), and tractive resistance increases (Dunn, 1959). The information was collected at 41 cross sections near Geological Survey gaging stations, located on 29 rivers and creeks in Kansas, Nebraska, South Da- kota, Wyoming, and Montana. The channels are considered stable, for gaging-station records show only minor changes in the stage-discharge relation through the years of record. The selected channels contained less than 40 percent gravel, but neverthe— less displayed a considerable range of alluvial and hydrologic characteristics. The information collected includes the following: Channel width (w), maxi- mum channel depth (d), Width-depth ratio (F), mean annual discharge (Q), mean annual flood or the total discharge with a recurrence interval of 2.33 years ((9,), median grain size of bed and bank sediment (D50), percent silt-clay in bed (S..) and banks (8,), percent silt-clay in the perimeter of the channel (M) calculated as a weighted mean = w + 2d . As an indication of the range of variables occur- ring among the sampled sections, the extreme values for some alluvial, hydrologic, and morphologic char- acteristics of the channels are as follows: M Drainage area above gaging station .......... sq mi... 212 to 56,700 Channel width ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, feet... 25 to 800 Maximum channel depth ,,,,,,, 2.3 to 18 Width depth ratio ..................................................... 2.5 to 138 Median grain size (bed) ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, mm... 0.02 to 8.0 Median grain size (bank) ,,,,,,,,,,,,,,,,,,,,,,,,,, _.mm,,,, 0.01 to 0.33 Silt-clay in banks ,,,,,,,,,,,,,,,,, ,,,,, ,,,percent,,,_ 23 to 97 Silt-clay in bed ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, percent... 0.2 to 87 Silt-lay in perimeter of channel .......... percent 1.4 to 89 Mean annual discharge ...................................... cfs..._ 5.8‘to 5,155 Mean annual flood ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, cfs,,,, 311 to 48,000 That a relationship exists between channel width and depth and discharge is well known and has been discussed most recently by Nixon (1959). The col- lected data afford an opportunity to relate channel width and depth not only to discharge but also to other variables. Analyses of variance show that at the 0.05 level the following are significantly related to width: Percent silt—clay in banks, mean annual flood, mean annual discharge, weighted mean percent silt-clay. Percent silt-clay in the channel and median grain size in bed and banks are not significant at the 0.05 level. Mean annual flood and weighted mean per- cent silt-clay are most significantly related to width, for they are significant at the 0.001 level. These two variables were chosen for a multiple correlation analysis with channel width. The analysis yields the following equation for channel width: QbAfi w = 5.76 W (1) P—F'i‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—27 The results of tests of the reliability of simple cor- relations and the multiple correlation between w, QB, and M are as follows: wande wandM wand (Qb, M) Coefl‘icient of variation (7'2) ........ 0.71 0.55 0.83 Coefficient of correlation (r) ______ .85 .74 .91 Standard error in log units (Se) .21 .26 .16 The coefl‘icient of variation indicates that 71 per- cent of the variation of width from the mean is ex- plained by the use of Q, alone. Fifty-five percent of the variation of width from the mean is explained by the use of M alone. When Q, and M are combined by multiple correlation analysis, 83 percent of the variation of width from the mean is explained. The use of M explains 40 percent of the variation unex- plained by the use of Q, alone. Analyses of variance indicate that of all variables tested, Q, and M are most significantly related to channel depth, for they are significant at the 0.01 level. Multiple correlation analysis yields the fol- lowing equation: M38 szn W The results of tests of the reliability of simple cor- relations and the multiple correlation between d, Q,., and M are as follows: d = (2) dandM dand Qz. dand (M, Qb) Coefficient of variation (7*) ________ 0.13 0.10 0.41 Coefiicient of correlation (r) ______ .35 .32 .64 Standard error in log units (Se) .21 .21 .16 Partial correlation analysis shows that only 13 per- cent of the variation of depth from the mean is ex- plained by the use of M and only 10 percent through the use of (9,, alone. When (2,, and M are combined in the above equation, 41 percent of the variation is explained. This is a considerable improvement, but the unexplained variation is still great. In both cases the use of M improved the accuracy of calculation of channel width and depth. Con- siderable variability remains in the correlations, but perhaps some of this may be explained by the innate variability of ephemeral streams. In any event, the introduction of a parameter for sediment type seems necessary before the accuracy of calculations of channel width and depth can be improved. Although within the limits of the data used chan- nel width can be calculated with some confidence, the calculation of maximum depth is considerably less accurate. However, maximum depth can be cal- culated in another way, by the use of an equation developed previously for Width-depth ratio. Using data collected at 69 stations, which include the 41 with runoff data, it was found (Schumm, 1960b) that the channel shape expressed as a width-depth ratio (F) is related to M as follows: F = 255 M4“ (3) In a practical application of the above to the prediction of stable channel dimensions, width-depth ratio can be calculated by equation 3 and channel width by equation 1. Maximum channel depth can be calculated by the use of equation 2 or by dividing the calculated Width obtained by equation 1 by the calculated width-depth ratio. It is recognized that equations 1 and 2 are em- pirical equations developed from a small amount of existing data; however, they demonstrate that equa- tions for the calculation of channel width and depth can be significantly improved by the introduction of a parameter for sediment type. REFERENCES Burmister, D. M., 1952, Soil mechanics: New York, Columbia Univ. Press, 155 p. Dunn, I. S., 1959, Tractive resistance of cohesive channels: Am. Soc. Civil Engineers Proc., Soil Mechanics and Foundations Div. Jour., Paper 2062, v. 85, no. SM 3. Leliavsky, Serge, 1955, An introduction to fluvial hydraulics: London, Constable and Co. Ltd., 257 p. Nixon, Marshall, 1959, A study of the bank-full discharges of rivers in England and Wales: Inst. of Civil Engineers Proc., v. 12, p. 157—174. Schumm, S. A., 1960a, The effect of sediment type on the shape and stratification of some modern fluvial deposits: Am. Jour. Sci., v. 258, p. 177—184. ———, 1960b, The shape of alluvial channels in relation to sediment type: U.S. Geol. Survey Prof. Paper 352—B, p. 17—30. 52‘ B—28 GEOLOGICAL SURVEY RESEARCH 1961 14. SOME FACTORS INFLUENCING STREAMBANK ERODIBILITY By I. S. MCQUEEN, Denver, Gold. A device designed to simulate the erosive action of a gently flowing stream was used to erode pre- pared samples of sediments to determine what physi- cal properties control the erosion processes. Circular pats of disturbed sediments were pre- pared and their moisture content and packing were controlled. Preliminary results (tables 1 and 2) in- dicate qualitatively which soil characteristics are important in controlling susceptibility to erosion. TABLE 1,—A'verage erosion rates, in milligrams per square centimeter of erosion surface per minute, and physical properties of sediment samples from sources in Colorado and Wyoming Soils Soil properties Dry pack Undisturbed A B C D E Air dried soils: Erosion rates ......... mg/cmz/min 213.7 319.6 579 14.1 21.3 Moisture content .......... percent 2.0 2.0 1.2 ................ Bulk density ................. g/cc 1,58 1 62 1,61 1.56 1.83' Moist samples: .. Erosion rates ......... mg/cmz/min 144 238 491 7.7 4.9 Moisture content .......... percent 200 18. 0 13 . 2 15.7 26. 4 Bulk density ................. g/cc 1.37 1.62 1.59 1.36 1.35 Grain size distribution: Sand > .0625 mm ......... percent 22 30 35 Silt .004 to .0625 mm ........ do. . . 42 52 46 Clay < .004 mm ............ do... 36 18 19 Median diameter (Elsa) ............ mm .012 .037 .060 Sorting coefficient (V d75/d25) .......... 6.44 2. 83 2.13 TABLE 2.—Efiects of packing and moisture content on erodi- bility of pats of soil A Moisture Bulk density Erosion (percent) (g/cc) (mg/ cm2/ min) Pretreatment Dry Dry Dry pack Puddled pack Puddled pack Puddled Freshly prepared pat .............. 20 16 6 1.33 1.71 237. 4 3.9 Seasoned at $§ atmosphere ........ 20.1 17 2 1.41 1.80 50.0 .4 Seasoned at M atmosphere: Sample 1 .................... 14.8 18.3 1.56 1.79 125.2 .3 Sample2 .................... 14.9 18.3 1.51 1.81 140.9 .5 Air dry: Samplel .................... 2.0 19 1,65 1.92 205.8 91.2 Sample2 .................... 2.0 19 1.51 2.12 221.7 115.7 Average ................................... 1.48 1,86 163 . 3 35.3 APPARATUS AND METHODS The erosion device was designed to apply a uni- form eroding force to the vertical face of a cylindri- cal pat of soil 3 inches in diameter and up to 3 inches high. The force applied is equivalent to that of a stream flowing past a vertical streambank with a flow velocity of 1.2 fps measured at a point 0.1 foot from the bank. Circular pats of disturbed sediments were pre- pared by two methods (dry packed and puddled) as follows: Dry packed—300 g of soil passing a No. 10 U. S. Standard sieve (2 mm) was placed in a paper-lined Buchner funnel with a funnel tremie. After satura- tion from the bottom with distilled water a vacuum was applied to the funnel to consolidate the sample pat and reduce the moisture content to approximately field capacity. Puddled.—300 g of soil passing a No. 10 U. S. Standard sieve (2 mm) was saturated with distilled water and mixed thoroughly. This was then trans- ferred to a paper-lined Buchner funnel and a vacuum was applied to reduce the moisture content to ap- proximately field capacity. Following preparation, the pats were removed from the funnels and some of each kind of pat were tested in the erosion device immediately, some were seasoned on a Richards pressure plate at specified moisture tensions, and some were air dried before testing. In addition to the disturbed soil pats, four rela- tively undisturbed samples of two soils (D and E, table 1) were obtained with a Lutz sampler. Two of these were saturated and then drained to field moisture condition on a Richards pressure plate be- fore testing. The other two were air dried before testing on the erosion device. The results of the erosion tests and the physical properties of the samples are shown in tables 1 and 2. Grain size distributiOn was not obtained for the undisturbed samples. SOIL FACTORS AND ERODIBILITY Among the important soil properties that control erosion are antecedent moisture, grain size distri- bution, packing, and chemistry. The soils used were chosen and the sample pats were prepared to indi- cate which soil properties have the greatest influence on erosion. Differences in antecedent moisture cause differ- ences in the erodibility of a soil (table 2). Air dry pats erode rapidly because of forces developed by the hydration of clay particles and reduced cohesion -, SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—29 between particles. This is more evident in the puddled than in the dry-packed samples because the expansion of the clay particles is more disruptive in a consolidated tightly packed sample. This hydra- tion or “slaking” action may explain why intermit- tent streams sometimes have higher rates of erosion than perennial streams. The erosion rate of moist soils increases as moisture content increases. The erodibility of soils is influenced by the grain- size distribution (table 1). In general, a poorly sorted sediment with a small median-grain size will resist erosion better than a well-sorted sediment with a larger median-grain size. This may not, hoWever, hold true for coarse sands in streams with low velocities. Packing includes a group of related properties such as porosity, bulk density, structure, texture, cementing, and pore-size distribution that are asso- ciated with the way the sediments are deposited and the forces applied to them since deposition. The two methods of sample preparation were used to simu- late extremes of packing. The erosion rates of the dry-packed samples were from 2 to over 400 times as high as the corresponding puddled samples (table 2), indicating that differences in packing can cause extreme differences in the erodibility of a sediment. The effect of chemistry on erodibility was not de- fined by the data obtained because it was masked by the effects of packing and antecedent moisture content. CONCLUSIONS This study was undertaken to explore the feasi- bility of determining in the laboratory an erodibility index for soils. For such an index to be of value, the erodibility of a given soil would have to be constant or would have to have a direct relation to some measurable property of the soil. The data obtained indicate that erodibility of a given soil is extremely variable. It is influenced by packing and by ante- cedent moisture content. Erosion rates determined on disturbed samples have little relation to actual erosion because the change in packing resulting from the disturbance changes the erodibility. Changes in moisture content and the freezing and thawing of natural undisturbed sediments may change their packing and hence change their erodibility so much that any index obtained would have little meaning in terms of actual field erosion rates. Comparisons can be made between different sedi- ments to determine which are more susceptible to erosion but the rate of erosion to be expected under a given set of conditions cannot as yet be determined from laboratory analyses of sediments. 5s 15. AN EXAMPLE OF CHANNEL AGGRADATION INDUCED BY FLOOD CONTROL By NORMAN J. KING, Denver, Colo. Studies by Leopold and Miller (1956) show that ephemeral streams, like perennial streams, maintain a quasi-equilibrium between erosion and deposition. A change in one or more of the hydraulic factors affecting the stream system results in adjustments in the other factors accordingly. Below a stream junction, for example, the increased discharge should be accompanied by a corresponding increase in chan- nel dimensions since Q =wdv, in which Q is dis- charge, w is width, d is depth, and v is velocity. Leopold and Miller (1956) show that width, depth, and velocity change in the downstream direction as simple power functions of discharge. Significantly, the power function relating width to discharge ap- proximates the sum of the power functions relating depth and velocity to discharge. It follows, there— fore, that width—the channel dimension in ephe- meral streams that can be measured most easily— is also the most responsive to changes in discharge. Measurements above and below arroyo junctions made by Miller (1958, table 4) show that with few exceptions the width below the junction of all but very small arroyos is equal to or greater than the width of the larger tributary. Based on the expres- sion (1 = k (b+c), in which a. is the channel width below the junction and b and c are the tributary widths, Miller’s measurements show the coeflicient k to average 0.68. If increased discharge forms a wider channel be- low a junction, it might be reasoned that a decrease B-30 GEOLOGICAL SURVEY RESEARCH 1961 Section SB Section 5A 5 FEET Section 3 50 FEET 100 o 100 ZOOFEET \j' I—A._|_A_l_l—_L_—J ‘ CONTOUR INTERVAL 2 FEET b Conant A ‘: \ V13 u<\4 Sechon l EXPLANATlON o—-——-——o \ Monumented channel cross section {or repeat surveys WYOMING Survey of October l959 Survey of October 1957 Survey of June I955 FIGURE 15.1.—Cross sections showing progressive aggradation in the channel of Conant Creek downstream from the mouth of Logan Draw, Fremont County, Wyo. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 in discharge in one of the tributaries as a result of artificial controls would have the opposite effect. At first, aggradation would be expected because flow emerging from the uncontrolled tributary would spread across the wider reach thereby decreasing its depth and velocity of flow. According to Schumm and Hadley (1957) aggradation would continue un- til the bed of the channel becomes oversteepened; then the newly formed deposit would be trenched by headward erosion to form a channel that is once again in quasi-equilibrium with the discharge. Completion by the Bureau of Land Management in 1953 of a flood-control and water-use project on Logan Draw in the southeastern part of the Wind River basin, Wyoming (King, 1959), is affording an opportunity to test the above reasoning, to measure the rates of aggradation, and to determine the time necessary to complete a cycle of channel adjustment. Logan Draw is an ephemeral stream that heads on Beaver Rim and trends generally northward to its junction with Conant Creek, which in turn drains through Muskrat Creek to the Wind River. Above the junction of Logan Draw and Conant Creek the drainage basins of the two streams are very much alike. Logan Draw has a channel length of 21.3 miles, a drainage area of 60.4 square miles, and a sandy bed that carries perennial underflow. Conant Creek above the junction has a channel length of 18.4 miles, a drainage area of 58.9 square miles, and a sandy bed that also carries perennial underflow. Both basins head at about the same altitude on B—31 Beaver Rim, experience the same general storm events, have similar topography, and are underlain by the same general rock types. It is probable, there- fore, that both channels experience flow simul- taneously, that their discharge is of about the same magnitude, and that the peak discharges reach the junction at about the same time. A comparison of channel cross sections above and below the junction (fig. 15.1) Show an increase in width below the junction. Depending on the points of measurement the coefiicient k of Miller (1958, p. 13) ranges from about 0.6 to 0.8. Since completion of the water-control structures in Logan basin, no flows have reached the mouth of Logan Draw, whereas numerous runoff events have occurred in Conant Creek. The channel downstream from the junction has aggraded as expected (fig. 15.1). This in turn has induced aggradation in both tributary channels for a short distance above the junction (sections 5A and 53, fig. 15.1). However, the newly formed deposit thins rapidly upstream so that no aggradation has occurred at section 68 (fig. 15.1) on Logan Draw and almost a foot of channel degradation has occurred at section 6A (fig. 15.1) on Conant Creek. In the aggraded reach the small inner channel that normally contained low flows has been largely filled and is now protected by vegetation that induces further aggradation (fig. 15.2). Repeat surveys (fig. 15.1) show that the greatest aggrada- tion (2.7 acre-feet in the surveyed reach) occurred during the period 1955—57. Aggradation in the FIGURE 15.2.—Conant Creek channel downstream from the mouth of Logan Draw (1960). Only vestiges remain of the inner channel that once carried 10w flows. I B—32 GEOLOGICAL SURVEY RESEARCH 1961 same reach during the periods 1957—59 and 1959—60 was 0.7 and 0.3 acre-foot respectively. The number of runoff events, the amount of run- off, or the maximum discharge of Conant Creek dur- ing the period (1955—60) is not known. However, these data are available for Logan Draw and are believed to be representative of Conant Creek basin for reasons previously stated. These data show no unusual storm events or high discharges, but they do show a wide range in runoff during the periods between surveys. For example, runoff during the period 1955—57 was 28.3 acre-feet per square mile compared to 5.1 and 3.2 acre—feet per square mile during the periods 1957—59 and 1959—60, respec- tively. The data are admittedly meager, but they ’X‘ suggest that runoff and the amount of sediment de- posited in the reach shown on figure 15.1 are directly proportional. REFERENCES King, N. J., 1959, Hydrologic data, Wind River and Fifteen Mile Creek basins, Wyoming, 1947—54: U.S. Geol. Survey Water-Supply Paper 1475—A, p. 1—44. Leopold, L. B., and Miller, J. P., 1956, Ephemeral streams—— Hydraulic factors and their relation to the drainage net: U.S. Geol. Survey Prof. Paper 282—A, p. 1—37. Miller, J. P., 1958, High mountain streams—Effects of geology on channel characteristics and bed material: New Mexico Bur. Mines and Mineral Resources Mem. 4, p. 1~52. Schumm, S. A., and Hadley, R. F., 1957, Arroyos and the semi- arid cycle of erosion: Am. Jour. Sci., v. 255, p. 161—174. 16. SOME EFFECTS OF MICROCLIMATE ON SLOPE MORPHOLOGY AND DRAINAGE BASIN DEVELOPMENT By RICHARD F. HADLEY, Denver, Colo. Northerly facing slopes generally are steeper, less dissected, and support a more luxuriant growth of vegetation than southerly facing slopes, which often are deeply rilled and nearly barren. Because of these differences in erosion there is a tendency for the thalweg of the major stream channel in an east-west oriented basin to be shifted to the south side of the valley floor by the debris fans and alluvial aprons of eroded material derived from the south-facing slopes. This type of channel migration has caused an asym- metrical development of many drainage basins studied by the writer in the High Plains, by Bass (1929) in Kansas, Melton (1960‘) in southeastern Wyoming and southern Arizona, and Emery (1947) in southern California where geology and regional climatic conditions are distinctly different. An at- tempt is made here to state quantitatively the effects on basin morphology and drainage development due to direction of slope or the exposure, or more pre- cisely, due to the microclimate. A preliminary study was made in the Cheyenne River basin of east-central Wyoming in six small drainage basins underlain by the Fort Union for- mation of Paleocene age. The bedrock units are virtually flat-lying, thus minimizing the possibility of downdip migration of stream channels and asym- V metrical basin development that might be caused by folding. Slope gradients are compared with exposure on figure 16.1 for an area of one-half square mile that includes part of the drainage areas of the six basins in which the other measurements were made. The slope of the land surface and direction of exposure were measured at 50 points equally spaced in a grid. The diagram shows that the steepest slopes face ’ north, northeast, and northwest, whereas the gen- tlest slopes face south, southeast, and south-south- west. ' . Vegetation counts made on several slopes using line-intercept transects show that the plant cover on southerly-facing slopes is only 28 percent of that occurring on northerly-facing slopes. The sparse vegetation cover on southerly-facing slopes is prob- ably caused by moisture deficiency due to rapid evaporation and melting of snow cover on the slopes that receive more direct solar radiation. Vegetation protects the slope from sheet erosion and rilling. Drainage density, expressed as miles of channel per square mile of drainage area, was determined separately for both the north and south sides of the six drainage basins. The basins were divided into two sides by a line virtually parallel to the axial channel in each basin. Results of these computations, A44 %A_.__} ‘—_‘__s___——) SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 NORTH w A « ’9‘“ 4—- h" WEST EAST SOUTH FIGURE 16.1.—Diagram showing relation between exposure ' and degree of slope at 50 localities. tabulated below, show that the drainage density on the south-facing sides of the basins is more than twice that on the north-facing sides. Drainage density, in miles per square mile, for six basins in east-central Wyoming Drainage density Drainage basin Area (fig. 162) (sq miles) North-facing South-facing side side 1 ................. 0. 16 5.0 15. l 2 ................. . 10 3 . 3 12 . l 3 ................. .09 6 . 2 17.0 4 ................. . 14 (i . 2 8. 5 5 ................. .76 5.0 8. 5 6 ................. .23 5 . (i 6. 7 Average ................. 5 .2 11 . 3 Drainage basin asymmetry has been expressed as the difference in slope angles on the north- and south-facing slopes within a single basin (Emery, 1947; Melton, 1960). In the six drainage basins considered here, asymmetry is simply a measure of the deviation of the main channel from a position along the central axis of the basin. Several measure- ments were made of the distance from the main channel to both north and south drainage divides in each of the basins in figure 16.2 (p. B—34). The lines of measurement were perpendicular to the axis of the channel. The ratio of the mean ,Value of all measurements from the channel to the northern B-33 divide to the mean value of all measurements to the southern divide in each basin is termed the index of symmetry. Anlindex of 1.0 denotes perfect sym- metry. The indexes of symmetry range from 1.22 to 1.97 for the six basins indicating that the main channel in each of these basins has been displaced appreciably to the lsouth by erosional debris derived from south-facing slopes. A reconnaissance has been made of basins having a wider range of bedrock and climate to determine the relative importance of the several variables being considered. A group of drainage basins was selected along a traverse nearly parallel to the 15- inch rainfall line in the western part of the High Plains from central Texas to northwestern Ne- braska. Thus, the variable parameter of mean an- nual rainfall, as it might affect slope erosion and plant life, was minimized and the differences caused by mean annual temperature, particularly the fre- quency of freezing and thawing, were accentuated. The basins in the southern part of the High Plains were underlain by the Ogallala formation of Pliocene age and the basins in northwestern Nebraska were underlain by the Brule and Chadron formations of Oligocene age. Measurements included degree and direction of slope and basin symmetry. These data are summarized as follows: Number of I Average Mean slope (percent) basins Location of basins index of symmetry North-facing South-facing V 4 .......... Lat 32° N.; near 1 .38 20 l9 Big Spring, Tex. 4 .......... Lat 41° N.; near 0.92 24 23 Cheyenne, Wyo. 2 .......... Lat 43° N.; near 1 .37 23 16 Harrison, Nebr. The indexes of symmetry for the basins near Cheyenne, Wyo. are contradictory to the indexes for the other basins studied, but this may be due to differences in the resistance to erosion of gravel in the Ogallala formation, which underlies the basins. REFERENCES Bass, N. W., 1929, Geology of Cowley County, Kansas: Kansas State Geol. Survey Bull. 12, p. 19. Emery, K. 0., 1947, Asymmetrical valleys of San Diego County, Calif.: Bull. So. Calif. Acad. Sci., v. 46, pt. 2, p. 61—70. Melton, M. A., 1960, Intravalley variation in slope angles related to microclimate and erosional environment: Bull. Geol. Soc. America, v. 71, p. 133—144. B—34 l 2 1:1.75 1:1.50 1:1.48 O l_______s_.___l GEOLOGICAL SURVEY RESEARCH 1961 I = 1.22 i D \ Casper ., , “A/ “x l . I [x i / \\' INDEX MAP OF WYOMING SHOWING LOCATION OF STUDY BASINS [21.52 1/2 1 MILE FIGURE 16.2.——Maps of drainage network in six basins. I is index of symmetry. 6% 17. HYDROLOGIC SIGNIFICANCE OF BURIED VALLEYS IN GLACIAL DRIFT By STANLEY E. NORRIS and GEORGE W. WHITE, Columbus, Ohio Work done in cooperation with the Ohio Department of Natural Resources, Division of Water Bedrock valleys containing permeable outwash deposits are recognized as important sources of ground—water supply in glaciated regions. Com- monly, in water-resources investigations of drift— covered areas, contour maps are made of the bed- rock surface, and the buried valley systems are described and interpreted. These studies have pro— vided data of considerable value, not only about ground-water resources, but also about the sequence and chronology of Pleistocene events. Similarly, buried valleys cut in till, rather than in bedrock, have been discovered in northeastern Ohio, in the course of current investigations on the hydrology of the glacial deposits. Such valleys have been ob- served in deep cuts for highways and strip mines, and recognized elsewhere by analysis of subsurface and hydrologic data. For example, near Ashland, Ohio, during construction of Interstate Route 71 in November 1958, a spring with a discharge of ap-» proximately 165 gallons per minute was opened by the power shovel when a deep cut was made in thick till. The water flowed from an interbedded deposit SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1—146 of silt and sand containing a minor amount of coarse gravel which, at the orifice, occurs in a shal— low Valley in a gray unnamed till at what is now known to be a disconformity between this till and an overlying till recently named the Millbrook (White, written communication, 1961). The relatively large discharge of the spring strikingly demonstrates that large quantities of water can be transmitted through glacial materials of generally low permeability. Permeable deposits in till-enclosed valleys consti- tute zones of relatively high permeability in the till, and are highly important in ground-water cir- culatory systems in areas of glacial terrane. They function much as do open joints and solution cavi- ties in limestone in conducting water through an otherwise poorly permeable medium. The depo-its they contain are typically referred to by well drill- ers as “gravel pockets” or “gravel stringers” in the till. Locally, the deposits are sources of water to farm and suburban wells; however, their signifi- cance as aquifers has been generally overlooked. These buried deposits are important as potential sources of water in many so-called “water-short” areas in northeastern Ohio, where thick till gener- ally overlies relatively impermeable bedrock. Some of the buried valleys in till appear to have been cut by streams in interglacial or interstadial times and filled during these times, as illustrated in figure 17.1. Others, as in the example in figure 17.2, appear to have been cut by meltwater streams from nearby ice and filled by ice readvance before any FIGURE 17.1.—Sketch of cut made for superhighway, NElA— NWV; sec. 33, Perry Township, Morrow County, Ohio, showing buried valley in till. 1, Till, very dark gray, calcareous; 2, till, yellow-brown or olive-brown, calcare- ous; 3, till, yellow-brown, noncalcareous; 4, sand, fine, calcareous, water—bearing; 5, silt, sandy, upper part non- calcareous; 6, clay, very dark gray; 7, silt and colluvium, highly weathered; 8, till, dark-brown, calcareous; 9, soil and weathered dark-brown till. n 25 so F 55‘ 75 loo I 5 . / / / ///// ’/// / /, / ///,/ /////,/’/f FIGURE 17.2.—Sketch of cut made for superhighway, center of sec. 27, Perry Township, Richland County, Ohio, showing buried shallow valley in lowest of three tills. 1, Till, dark drab gray, calcareous; 2, till, olive-brown, calcareous; 3, silt, yellow; 4, gravel and coarse sand, calcareous, water- bearing; spring in each of 3 units; 5, till, bluish-gray, calcareous; 6, till, yellow-brown, calcareous; 7, till, dark- brown, calcareous below 4 feet; depth of leaching shown by dashed line. weathering of the deposits could take place. The examples illustrated are typical of many that have been found. Some, as in figure 17.1, are completely preserved beneath a later till cover; others, as in figure 17.2, have had part of their fillings (and probably part of their upper valley walls as well) removed by erosion before or during later till deposition. These may be similar, in part, to buried meltwater channels in Minnesota described by Schneider and Rodis (1959), at least some of which may have been cut in glacial drift rather than bedrock. - These buried valleys are unconformities and oc- cur at the contact between two tills. Individual tills in northeastern Ohio have been distinguished and mapped (White, 1960, and Art 176) on the basis of variations in their mineralogy, petrology, tex- ture, color, and mechanical properties. Identifica- tion of till contacts in the subsurface provides clues to the location of buried valleys that may contain permeable sand and gravel deposits. ' REFERENCES Schneider, Robert, and Rodis, H. G., 1959, Aquifers in melt» water channels along the southwest flank of the Des Moines lobe, Lyon County, Southeastern Minnesota. [abs]: Geol. Soc. America Bull., v. 70, p. 1671. White, G. W., 1960, Classification of Wisconsin glacial deposits in northeastern Ohio: U.S. Geol. Survey Bull. 1121—A. 12 p. ’5? B—36 GEOLOGICAL SURVEY RESEARCH 1961 18. I PLAN TO SALVAGE EVAPOTRANSPIRATION LOSSES IN THE CENTRAL SEVIER VALLEY, UTAH By RICHARD A. YOUNG and CARL H. CARPENTER, Richfield, Utah Work done in cooperation with the Utah State Engineer The Sevier River, as a source of irrigation water, is one of the most highly developed streams in the United States. At four points along its course in the central Sevier Valley the stream is completely diverted into irrigation systems, but return flow and ground-water discharge replenish the flOw for downstream users. Severe drought conditions, ex- tensive invasion by phreatophytes of low economic value, poor drainage practices, and outmoded irri- gation systems have combined in the past decade to diminish the irrigation supply. A ground-water in- vestigation, begun in 1956 and completed in 1960, has resulted in a greater knowledge of the hydrology of this highly complex river system. The central Sevier Valley (fig. 18.1) occupies a syncline modified by a graben (fig. 18.2). The initial syncline was formed in late Jurassic time, and fold- ing continued throughout Cretaceous and Tertiary times. The faulting that formed the graben may have started after Miocene time because it involves volcanic rocks of Oligocene or Miocene age. Re- newed faulting took place in Pleistocene and Recent time and cut the Sevier River formation of late Pliocene or early Pleistocene age. The graben was subsequently filled with alluvium from the side slopes and with poorly sorted valley fill deposited by the ancestral Sevier River. Faulting, lava flows, and salt-dome intrusions have resulted in constric- tions across the valley that form basins which con- tain large supplies of ground water. Largest of these basins are Circle Valley, the Sevier-Sigurd area, and the Gunnison-Sevier Bridge area. The ground water in these basins is in approxi- mate dynamic equilibrium; that is, ground-water inflow essentially equals ground-water outflow. The . basins are filled to capacity and the ground water is under artesian pressure throughout much of the valley. The Sevier River acquires the overflow or natural ground-water discharge from each basin; this flow is diverted at some downstream point to satisfy irrigation demands. It has long been considered impossible to utilize ground water to stabilize or increase the irrigation supply without interference with established water rights. Results of this investigation verify this premise but also suggest that some water now wasted by low—value vegetation may be salvaged. The con- fining materials that cover the artesian basins in the central Sevier Valley are permeable. Thus the artesian pressure from underneath, together with saturation by irrigation from above, raises the water table to a level within reach of phreatophytes. Dense growths of low~value phreatophytes cover much of the land surface overlying the artesian areas, and an estimated 60,000 to 70,000 acre-feet of ground water is lost by evapotranspiration annually from the three main basins. Much of the phreato- phyte growth occurs along river banks, creek chan- nels, drains, and irrigation canals. A coordinated program of phreatophyte eradication, improved ir- rigation management, and lowering of the high water table by improved drainage practices and by pump- ing of wells could salvage as much as 50 percent of the water annually lost to evapotranspiration by low-value plants. It is diflicult to estimate to what extent pumping may be utilized to salvage evapotranspiration losses without interference with established water rights, but careful development should minimize that inter- ference. The following table gives a breakdown of estimated annual ground-water discharge from the three main basins: Estimated loss by low-value phreatophytes (acre feet) Other artificial and natural discharge from the ground— water basins. Includes springs, drains, flowing wells, and pumped wells (acre feet) Basin Circle Valley ............. 10,000 5,000 Sevier-Sigurd ............. 30 , 000 37 , 000 Gunnison-Sevier Bridge. . . . 30,000 18,000 Total ............. 70 , 000 60 , 000 This table indicates that more water is lost by low-value phreatophytes than is used from all pres- ent ground-water sources. If half the water now lost to low-value phreatophytes could be salvaged by pumping without seriously affecting the present SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 EXPLANATION Semier Budge Reservoir River / Boundary of alluvium A\A , Location of cross section 0 Well used in constructing cross section v. o'Si rd ‘9 1' 7"." 8'“ 2%— I ,- / I. “: , 12‘}! SEVIER-SlGURD I 5 AREA « Cheek ‘l' 2 Q}? Marysvyeo 'x‘ o UTAH gum: AREA - . .-‘ .--..-' . . l‘. O ., 5‘ _..._....‘.l‘ ' 10 “‘15MILES L_.__;____..L—l 2.) - :s .’ /" “r .'l _.v '1' ’ 1' '- l ‘ FIGURE 18.1.—Map of central Sevier Valley, Utah, showing areas of ground-water storage. GEOLOGICAL SURVEY RESEARCH 1961 A , E X P LA N ATl O N r Pleistocene and Recent deposits, undifferentiated Crazy Hollow formation 0 o o o 000a (Spieker, 1949) :0 2 ° 9 o o . 0 ° 0 ° _. . - . . ~~ o o O o . 5750'—- . . , _ — 5750' Sand, Silt, and clay depos1ts Water-bearing gravel depos1ts Crazy Hollow formation (Spieker, 1949) .5 l .D N . o «I ‘c 5500' — Green River .4 m g u _ 5500' formation El 2 A (‘5’, in o m A | w: . m S g a «'3 H 3‘; N ..... pg ,_ (.I) (\II a) .i' a.) I . V o B Q: B : v .C 5 .E \l i’ 5 *5 ‘3 a 9 5250'« - . . 3 +3 c)”; i3 . — 5250' . 0 Jul .9 CE I C (V! '. 2 Flagstaff limestone ~ g 5000' — - b — 5000' HS ‘t ' G.) d o '— O 0 ,_ \i l _ 47 , 4750 m 50 n: n: 3 Lu 5 _ ; 3 s L” 5 Lu 0) 4500— k" a” o . — 4500’ ‘ . n Sewer River forrna“o O 1 ? MILES VERTICAL EXAGGERATION X16 FIGURE 18.2.—Geologic section across Sevier Valley. rights, an additional 30,000 to 35,000 acre-feet might be made available in the central Sevier Valley. A water-budget study was made in the Sevier- Sigurd area to estimate the annual yield that might be obtained by pumping. This study indicated that evapotranspiration amounted to about 55,000 acre- feet of water in 1957 and about 65,000 acre-feet in 1958—about half of it consumptive waste. The water-budget study also indicated that, for a decline of one foot in average ground—water level, about 20,000 acre-feet of ground-water was discharged. The artesian head of the wells and springs in the Sevier-Sigurd area ranges from 1 to 7 feet above land surface. If large wells were spaced and con- structed properly, the. Sevier-Sigurd basin might yield an additional 15,000 acre—feet of water to wells annually without seriously affecting present flowing wells and springs. Similarly, in Circle Valley and in the Gunnison-Sevier Bridge area an additional 5,000 and 15,000 acre-feet respectively might be de- veloped, for a total of about 35,000 acre-feet in the central Sevier Valley. REFERENCE Spieker, E. M., 1949, The transition between the Colorado Plateaus and the Great Basin in central Utah: Utah Geol. Soc. Guidebook no. 4, 106 p. 6Q SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—39 19. RELATION BETWEEN STORAGE CHANGES AT THE WATER TABLE AND OBSERVED WATER-LEVEL CHANGES By R. W. STALLMAN, Denver, Colo. Meinzer (1923, p. 28) defined specific yield as the ratio of (a) the water removed by gravity drainage from a saturated rock to (b) the volume of the rock. Specific yield, both as a concept and as a characteri- zation of the hydraulic properties of water-bearing materials, plays a useful role in hydrologic studies. However, in many situations the variables affecting the ground—water flow system are not interrelated adequately by the basic assumptions inherent in the specific yield concept. Specific yield may be defined algebraically as @ y dt (1) where q is the rate of increase of water storage in the saturated zone (expressed as a length per unit time), S, is the specific yield, and dh/dt is the slope of the curve water-table height (h) versus time (15). Equation ( 1) was adapted as the basis for the “trans- piration-well method” by White (1932), was applied by Gatewood and others (1950) for measuring ground-water use by vegetation, and is still in use (Stallman, Art. 20). If the position of the water table changes in response to changes in flow in the saturated zone, equation (1) may be considered an abbreviation of a differential equation which defines the relationship among head, storage, and aquifer-conductivity with respect to water movement. Two-dimensional flow through a homogeneous unconfined aquifer may be expressed approximately as 83h 62h ah T [6x2 + 31F] +W I S"? (2) in which T is the aquifer transmissibility, and W is the rate of recharge to the saturated zone expressed as a length per unit time. Flow in the saturated zone as defined by equation (2) is illustrated in figure 19.1. The first term on the left side of equation (2) is an expression of the rate of change of storage due to variations in flow in the x-y plane. The accretion rate W also accounts for a part of the total rate of change of storage and is either added to or subtracted from the flow through the aquifer. Thus, the rate W, as defined, represents the rate of interchange of liquid between the sat- urated and unsaturated zones. (12S —Land surface Unsaturated _ 5 CL“ 41’ zone /, } Y 6f __ __________ l,” W _- fl f , } 5y at ‘ ,z-fix __________ //‘%‘ Saturated 62h <__,l zone 67 / >1 / ‘— AX H/ FIGURE 19.1.——Flow relations in the saturated zone. In equation (1), (1 generally is assumed to be the rate at which water is removed from the saturated zone by evapotranspiration. This presumes that q : W, and that the first term in equation (2) is negligible compared with W. Though this might be considered a reasonable presumption, there has been little, if any, evidence developed to support it. From data for one small group of wells (Stallman, 1956, p. 454) it was determined that lateral flow changes, given by the first term in equation (2), accounted for more than one-third of the calculated W during a short period of observation. One set of water-level altitudes showed W to be a positive quantity while ah/at was negative according to analysis by equa- tion (2). Thus, equation (1) would have indicated a water loss from the zone of saturation even though recharge occurred, as demonstrated by the analysis using equation (2). This one example suggesting analytical inadequacy in equation (1) cannot be con- sidered conclusive evidence that equation (2) must always be used for calculating W; it emphasizes the need for a more cautious approach in assigning physical significance to q as calculated by means of equation (1). B—40 In the derivation of equations (1) and (2) it was f assumed that flow in the unsaturated zone does not affect the storage changes in the saturated zone. This assumption is inherent in the definition of specific yield. However, the saturated and, unsatu- rated zones form one continuous hydraulic system. Thus, even though the hydraulic characteristics of both zones are different from one another, it should be evident from the fundamental concepts of hydrau- lics that any change of either head or velocity in the unsaturated zone will be reflected to some degree as a change of head everywhere in the saturated zone. Therefore, the water table will move in re- sponse to the distribution of flow in both contiguous zones, and it does not appear reasonable to relate the position of the water table solely to flow in the saturated zone as has been done in the derivation of equations (1) and (2). The relation between discharge from the saturated zone and its effect on the position of the water table is shown schematically in figure 19.2. The column shown represents a flow tube which extends from some distant point where head is controlled by say, surface-water stages, through the aquifer to a point on the land surface. Flow through the saturated zone discharges into the unsaturated zone, from which it is discharged into the atmosphere by evapo- transpiration. At a particular discharge rate A, a given head distribution will be established in the system commensurate with all the hydraulic bound- ary conditions imposed on the aquifer. The resulting water-table position is at a. If the discharge through the surface is increased to rate 3, the head at all points in the system will be decreased to accommo- date the increase in velocity at all points in the system. Thus, with discharge at rate B the position of the water table is b. For a given value of A/B, the difference between the altitudes of d and b is chiefly dependent on the ratio of the hydraulic con- ductivities of the saturated and unsaturated zones to steady-state flow, and. therefore is not necessarily directly related to a change of storage inthe system. Flow through the unsaturated zone isrchiefly vertical. Thus,,,the extent to which the water-table positionis dependent on flow in the unsaturated, zone might be determined from study'of vertical flow components in the vicinity of the water table. Field measurement of such vertical flow components is not practicable by the techniques now available, but recent work (Mosetti, 1960; Suzuki, 1960; and Stallman, 1960) has indicated the feasibility of measuring very small ground- water velocities by analysis of the underground temperature distribu— GEOLOGICAL SURVEY RESEARCH 1961 B 'Discharge A a, . C O N U 2 2< 3 $4 0 U) C D ______ _____ g— Waier -tob|e positions 2 > —————— ——-—- b o ._ .N '0 2d 2 cm 2 D m L Distant point in aquifer FIGURE 19.2.—Change of the water-table position due to changes in rate of discharge from the saturated zone. tion. From such data, it should be possible to make a direct evaluation of the adequacy of equations (1) and (2), and to document the significance of the concept illustrated by figure 19.2. REFERENCES Gatewood, J. S., Robinson, T. W., Colby, B. R., Hem, J. D., and Halpenny, L. C., 1950, Use of water by bottom-land vege- tation in lower Safford Valley, Arizona: U.S. Geol. Sur- vey Water-Supply Paper '1103, 210 p. Meinzer, O. E., 1923, Outline of ground-water hydrology: U.S. Geol. Survey Water-Supply Paper 494, 71 p. Mosetti, Ferrucio, 1960, Thermometric study of the movement of ground water: (Presented orally by Prof. Mario Picotti), Internat. Union Geodesy and Geophysics Mtg., Helsinki. . Stallman, R. W., 1956, Numerical analysis of regional water levels to define aquifer hydrology: Am. Geophys. Union Trans, v. 37, p. 451—460. , 1960, Notes sur l’emploi de reseignements thermiques pour l’evaluation de la vitesse d’eau souterraine (Notes on the use of temperature data for computing ground- water velocity) : Soc. Hydrotechnique de France, Jour. de L'hydraulique (Nancy, 1960), Quest. 1, Rapp. 3, p. 1—7. ‘ Suzuki, Seitaro, 1960, Percolation measurements based on heat flow through soil with special reference to paddy . fields” Jour. Geophys. Res. p. 2883—2885. White, W. N. 1932, A method of estimating ground- water supplies based on discharge by plants and evaporation from soil—results of investigations in Escalante Valley, Utah: U.S. Geol. Survey Water—Supply Paper, 659—A, 105 p. ’X‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—41 20. THE SIGNIFICANCE OF VERTICAL FLOW COMPONENTS IN THE VICINITY OF PUMPING WELLS IN UNCONFINED AQUIFERS By R. W. STALLMAN, Denver, Colo. Most algebraic equations used for analyzing pump- ing tests (see Theis, 1935; Wenzel, 1942; Ferris, 1949; Jacob, 1950; and Brown, 1953, for example) have been derived using the assumption that flow to wells occurs only in horizontal planes as shown schematically on figure 20.1A. However, where the upper surface of the ground-water body is uncon- fined and free to move as head in the aquifer changes, paths of flow originate at the unconfined or free sur— face and terminate at the well as shown schemati- cally on figure 20.18. Downward flow from the free surface is most pronounced during the initial period of pumping. The water table is lowered most rapidly near the pumped well, and in that region the effects of downward movement on flow become progres- sively less significant as pumping continues. Thus, it is generally recognized that flow conditions be- come essentially like those found in artesian aquifers only after long periods of pumping in unconfined aquifers. Nevertheless, it is common practice to utilize the equations defining artesian conditions to determine the characteristics of unconfined aquifers from pumping tests lasting only a few hours. Valid- ity of such practice has been supported more by wishful thinking than by real evidence that the assumption of purely horizontal flow leads to a satisfactory analysis. Furthermore, there are as yet no quantitative data to indicate how long a period UM Pumped well owl-Omemc s Pumping level :4 // / , . / ,v ’ Confinmg beds . / / A ”a , / , w: :5. “U V“ ‘———d-———-y—— v“./ “—v Flow ' i . :' ‘——,* AqUIfer a“: —/ V / Conflning beds A. ARTESIAN CONDITIONS FIGURE 20.1.—Schematic diagrams of instantaneous flow paths. Pumping level of pumping is required before flow may be satis- factorily defined by the assumptions made in de- riving analytical expressions like the Theis equation. Boulton (1954) and Kirkham (1959) have de- veloped methods for analyzing unconfined flow to wells, taking account of the vertical flow components at the water table. However, these methods are founded on other restrictive assumptions, and pro- vide little or no direct evaluation of the effects of vertical flow components on radialjflow relations. Without such an evaluation the need for more lengthy analytical methods is open to question. The relative effects of vertical flow components on changes in head at the water table might be ascer— tained by a form of Boulton’s (1954, p. 568) differ- ential equation defining the free surface. For an anisotropic formation, Boulton’s equation is Silas _ as 2 as”, as P: ea “(5) t (a) *5 1'»: in which S, is the specific yield, 8 is the decline of the water table, 7" is the distance from the center of the well to the point where the decline is observed, 2 is the distance upward from the confining bed to the point where the decline is observed, t is time, and P, and P, are the permeabilities for radial and verti- cal flow of water, respectively. If the value of the Pumped well Aquifer (((( I (((( I mulu‘é‘uh‘ll Confining beds . H 7 , B. WATER-TABLE CONDITIONS B—42 left side of equation (1) is nearly equal to (a,/a,)‘~’, the effects of vertical flow components on the rate of water-table decline are negligible and the flow is essentially horizontal. Pumping-test data collected near Grand Island, Nebr., by Wenzel (1942, p. 117—122) afford an op- portunity for demonstrating, by means of equation (1), the effects of vertical flow components. The aquifer at the test site is composed of unsorted sands and gravels and is about 100 feet thick. The pumped well was 24 inches in diameter and was drilled to a depth of about 37 feet below the water table. Drawdowns were observed in 80 nearby ob- servation wells. According to Wenzel’s (1942, p. 125) analysis of the field data, S, : 0.2 and P, : 140 ft. per day, approximately. However, laboratory tests indicated (Wenzel, 1942, p. 118) that the value of P, at the water table may be much less, say as low as 65 ft. per day. Graphs of 8 versus 7‘ and 8 versus t are shown on figure 20.2 to illustrate the finite-difference method used for computing 33/315 and 38/31" from test ob- servations. This procedure was applied also to draw- downs observed at other times after pumping began. Values of as/at and 63/37“ computed for selected times are given in table 1. TABLE 1.—Drawdown rates and water-table gradients at r : 50 feet for Wenzel’s (1942) Grand Island, Nebr., pumping test I i I . 38 z t a? a: l i1 1 £1 a: (3—) (min) (ft/day) ar i Pr at I Pr 3: l ' _,_1_71V .11...,,.._ 1-.., 1... 1.,11_--___-_-1i _. .1...11_A ,, 7 _, a 50 ....... 11.0 2.7x10»! 1 1.6><1<10-2 0.2><10-I 300 ....... 2.9 2.9><10-2 4.1X10'3 8.9X10—‘ s.4><10~ 700 ....... 1.0 2.4x10—2 1.4x10-3 3.1x10-3 5.8X10‘* 2,000 ....... .45 2.4x10-2 6.4X10“ 1.4x10-s 5.0mm 1 Letting Sy/Pr : 0.2/140 day per ft from Wenzel’s (1942, p. 125) pump- ing-test analysis. 2 Letting Sy/Pr : 0.2/65 day per ft from Wenzel’s (1942, p. 118) labora- tory value of Pr near the water table. It is evident from table 1 that the radial flow com- ponents were not the chief influence on the rate of water—table decline, even after about a day and a half of pumping. This can be seen by comparing S” as 38>2 : 5.8 >< 1"? 07 a7 104, using P, from laboratory tests. Probably the value of P, determined in the laboratory is more nearly correct than the value obtained from Wenzel’s analysis of radial flow through the entire depth of the aquifer. The coefiicient S,,, the specific yield, is generally considered a constant in the equations used for the value of :1.4 X 10—3 with < GEOLOGICAL SURVEY RESEARCH 1961 0 I I l l DRAWDOWN IN FEET 3 Ql l I l l 20 4O 6O 8O RADIUS, IN FEET Time equals 500 minutes 0 I I I I as As 0.00 -5 . —-a _ —— = a) 5!: At 200 2x10 ft/mln E O = 2.88 ft/day LL] 1 — — Lu 0 2. H o g 0 Q g 2 — _ D O 3 I I I I I O 200 400 600 TIME, IN MINUTES Distance equals 50 feet FIGURE 20.2.—Drawdown changes with respect to distance and time (after Wenzel, 1942, p. 117—122). pumping-test analysis, and this was also assumed to be the case in table 1. However, pore drainage above the water table varies with time, and S, is small during the first few minutes of pumping, grad- ually increasing to a value of 0.2 after a long period of pumping. A three—dimensional electric analog study of the drawdowns observed during the first ten minutes of pumping indicated that S, probably did not exceed 0.01 during that interval. Such a low value of S, in the early part of the test would materially de- S, as . . . crease the value of?r a, bringing it more nearly equal to (as/ar)‘-’ than indicated in table 1. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 It can be shown that, at any time Q 00 (As S_// = 7r 21",, E), r A?” (2) in which Q is the rate of pumping, and 7'... is the radius of the pumped well. According to equation (2), S,, : 0.11 at t = 50 minutes in the Grand Island test. The error in the latter analysis is believed to be less than 20 percent. Thus, the conclusion drawn from table 1, that vertical flow components at this site are significant for at least 11/3 days of pumping, is not affected appreciably by changes in S, with respect to time. The aquifer tested is not unique in thickness, spe- cific yield, or permeability; therefore, vertical flow components may be important in most unconfined aquifers during the initial period of pumping. Equa- tions based on the assumption that flow is essentially horizontal thus are likely to yield erroneous values of both P and S,,, and additional error due to as- suming 8,, conztant may be expected if the duration of the test is only a few hours. B—43 REFERENCES Boulton, N. S., 1954, The drawdown of the water table under nonsteady conditions near a pumped well in an unconfined formation: Inst. Civil Engineers (British) Proc., p. 564—- 579. Brown, R. H., 1953, Selected procedures for analyzing aquifer test data: Am. Water Works Assoc. Jour., v. 45, p. 844— 866. Ferris, J. G., 1949, Ground water, Chap. 7, in C. O. Wisler and E. F. Brater, Hydrology: New York, John Wiley and Sons, 408 p. Jacob, C. E., 1950, Flow of ground water, Chap. 5, in Hunter Rouse, Engineering Hydraulics: New York, John Wiley and Sons, 1039 p. Kirkham, Don, 1959, Exact theory of flow into a partially penetrating well: Geophys. Res. Jour., v. 64, p. 1317—1327. Theis, C. V., 1935, The relation between the lowering of the piezometric surface and the rate and duration of dis- charge of a well using ground-water storage: Am. Geophys. Union Trans, 1). 519—524. Wenzel, L. K., 1942, Methods for determining permeability of waterbearing materials: U.S. Geol. Survey Water-Supply Paper 887, 192 p. 5% 21. METHODS FOR STUDY OF EVAPOTRANSPIRATION By 0. E. LEPPANEN, Phoenix, Ariz. The evaporation processes of nature are the larg- est item in the water balance of the United States. The 17 Western States receive 2,000 maf (million acre-feet) of precipitation of which MacKichan (1957) estimated that only 5 maf is used directly by man. C. H. Hardison (written communication Feb. 21, 1952) calculated the runoff from these states to be 440 maf—about 22 percent of the precipitation. J. S. Meyers (written communication, 1960) esti- mates that evaporation from free-water surfaces is 24 maf. Thus, most of the precipitation in the West returns to the atmosphere by evapotranspiration from vegetation and land surfaces. Most quantitative estimates of evapotranspiration are made by considering long-term averages of rain- fall and runofi” in a basin, or by analysis of irriga- tion records. These methods are not suitable for estimating short-term water demands or for assign- ing relative water-use indices to various vegetation- covered surfaces. More sensitive methods are de- sirable not only for direct practical application— but also for development of a better understanding of the physical mechanism involved, so that waste- ful evapotranspiration can be controlled. The most direct method of measuring evapotrans- piration is a water budget: first, the inflow (precipi- tation, irrigation) and outflow (seepage, runoff) are measured, then after accounting for changes in soil- moisture storage, the net loss is attributed to evapo- transpiration. This method fails, except under very special circumstances, because of difficulties in measurement. Another method is the energy budget. Directly analogous to the water budget, the energy budget accounts for inflow, outflow, and storage of heat. The singular advantage of this method lies in the fact that the term that describes evapotranspiration is large numerically, having been weighted by the energy necessary for change-of—phase. Measurement errors in water flow become less significant. The B—44 GEOLOGICAL SURVEY RESEARCH 1961 energy budget has been applied successfully to the measurement of evaporation from lakes and there is no theoretical reason why it could not be applied also to measurement of evapotranspiration. Experiments have been made in an area in eastern Nebraska to test the application of the energy budget. A site near Fairmont, Nebr., was carefully chosen in a loess plain with soil formed on Peorian loess. Below the Peorian, at a depth of about 5 meters, lies the Loveland loess. Nearby wells indicated ground water to be at depths exceeding 30 meters. The sur- face has a slope of about 1:750, and no runoff was anticipated or observed. The area had been seeded with alfalfa late in the previous season. The alfalfa ' grew slowly in April, rapidly in May, matured in June, and was mowed on June 30. A second crop then grew, but somewhat less vigorously. A water budget was first computed using the rec- ords from a local raingage and soil moisture data that were obtained from six sets of soil samples taken during the study. Information from a neutron-scat- tering soil-moisture meter, which was used several times weekly, allowed interpolation between samp- lings. Deep seepage, or percolation, was considered to be zero because of the existence at a depth of 5.2 meters of a buried soil that apparently was very impervious to soil-moisture movement. ’ The results of the water budget are shown in table 1. TABLE 1.—Evapotranspiration computed from the water budget for the experimental. site at Fairmont, Neb'r'., for selected periods, in centimeters of water Period, 1958 Change in Evapo— soil-moisture Precipitation transpiration From To storage April 14 ............. May13 ............ + 1.9 7.1 5.2 ,May 13 ............. June 9 ............. —23.0 4.0 27.0 JuneFJ.... .. July 15,... + 9.3 15.2 5.9 July15 .............. August5 ........... — 2.7- 9.5 12.2 August 5 ............ September 2 ........ —13.2 5.6 18.8 September2 ......... September 29.,..... + 6.4 _ 14.2 7.8 Total ........................................... i 55.6 6 9 l 7 . Measurement of items in the energy budget re- quired extensive instrumentation. A net exchange radiometer measured thermal radiation, the major energy source. Changes in heat storage in the soil, although small, were measured. Heat brought in by rain was accounted for. Heat conducted from the surface of vegetation as sensible heat was computed using the ratio developed by Bowen (1926)‘. The 1 Because a practical field instrument to measure the conducted heat is .not yet available, the Bowen ratio, which relates heat lost by conduction to heat lost by evaporation, has been widely used to compute conducted heat. temperature and humidity gradients above the sur- face were determined by measurements in the vege- tation and at levels of 1/2, 1, 2, and 8 meters above the vegetation. Anemometers were also installed at these levels. About 1.4 million observations of tem- peratures and humidities were analyzed using an electronic computer. Evapotranspiration, calculated from the water budget during a 168—day season, was 0.46 cm per day. Evapotranspiration, calculated from the energy budget ranged from 0.57 cm to 0.92 cm per day, depending on the levels above the surface that were used in selecting the meteorological data needed to calculate the Bowen ratio. These results suggest that the Bowen ratio, as calculated in this ex- periment, is not applicable to evapotranspiration measurement. To investigate the data for seasonal bias, and to observe the effect of changing the length of the observation period, evapotranspiration was calcu- lated for six periods of about a month each. Results are listed in table 2. The levels above the vegetation used in calculating the Bowen ratio are 1/2 and 1 meter. TABLE 2.——Compam‘son of water-budget and energy-budget evapotranspiration rates for intervals throughout the season, in centimeters of water per day Period, 1958 ...................... _.A_m__1___ __#_, Water-budget Energy-budget evapotranspiration evapotranspiration From To May13 .............. 0.18 041 June 9 1.00 .79 July 15 .16 .58 . August5.. .53 .55 September 2 .......... .67 .58 September 2 ........ September 29 ......... .29 .42 The results for' the shorter periods show no better agreement with the water budget than do the sea- sonal figures. Comparison with data from lakes indicates that the conducted—energy term is a large item in the evapotranspiration energy budget but is a small item in a lake-evaporation energy budget. The rea- son is that water absorbs and stores most of the radiant energy falling upon it, but vegetation con- verts radiant energy to a combination of conducted and latent heat. Thus, the theory and method of calculating the Bowen ratio becomes critical in the evapotranspiration energy budget. The energy- \’\ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 budget method is, however, theoretically correct, and further analyses of the data from this and similar experiments in determining the conducted energy should resolve discrepancies in results from the water-budget and energy-budget methods. B—45 REFERENCES Bowen, 1. S., 1926, The ratio of heat losses by conduction and by evaporation from any water surface: Phys. Rev., v. 27, p. 779—787. MacKichan, K. A., 1957, Estimated use of water in the United States, 1955: ms. Geol. Survey Circ. 398, 18 p. 'X‘ 22. WATER MOVEMENT AND ION DISTRIBUTION IN SOILS By R. F. MILLER and K. W. RATZLAFF, Denver, Colo. Divalent calcium and magnesium both have greater l replacing ability than monovalent sodil‘m in ion ex- change reactions with soil colloids (Kelley, 1948, p. 57). Therefore, when calcium and magnesium ex- ceed the sodium in water moving through the soil, the proportion of calcium and magnesium in solution should decrease in the direction of water movement as a result of adsorptitn to ion exchange surfaces, and the proportion of sodium should increase in the direction of water movement as a result of its dis- placement from ion exchange surfaces (Bible and Davis, 1955). Because of this relation, the direction and pattern of moisture movement in soils can be interpreted from soil chemistry. The depths to which untilled soils in arid and semiarid climates are most fre- quently wetted also are reflected by the relative con- centrations of soluble ions in the soil profiles. The greater solubility of sodium salts also permits sodium to move farther through the soil in the direc- tion of water movement than calcium or magnesium. This is especially true when the ions in solution are concentrated by the processes of evaporation and the use of water by plants—a condition that causes precipitation of the less soluble salts (Gardner and. others, 1957). ' The relations between water movement and ion distribution in two soils with different internal drain- age characteristics have been studied by the writers: The relative proportions of soluble calcium plus mag- nesium and sodium in consecutive vertical portions of the two soil profiles are expressed as differences in soluble sodium percentage (SSP). _ Soluble Na _ Soluble Na + (Ca + Mg) SSP X 100 A residual coarse-silt loam soil near Palo Alto, Calif, (table 1 and fig. 22.1) is characteristic of soils with unimpeded internal drainage. Winter rainfall frequently provides enough moisture to wet the base of the soil profile. The soluble sodium percentage in- creases with depth, as a result of progressive adsorp- tion of calcium and magnesium from soil water onto the ion exchange surfaces, whereas sodium is dis- placed from ion exchange surfaces into the water moving down through the soil profile. A gradual decrease in total salts in the soil with depth reflects the loss of ions from solution to ion exchange sur- faces and frequent flushing of the soil. A higher concentration of both calcium plus magnesium and sodium in the top five inches of soil as compared with the next layer below, indicates that precipita- tion of salts occurs as they are concentrated by evaporation. An alluvial medium-silt loam soil near Fort Apache, Ariz., (table 1 and fig. 22.1) is characteris- tic of deep permeable soils that commonly do not receive enough moisture to become wet throughout the profile. The A horizon is moistened by summer showers, but the B horizon is moistened to field ca- pacity primarily by snowmelt. Moisture apparently moves down into the C horizon only in response to temperature and moisture tension gradients. Ap- parently the buried B horizon impedes capillary movement of water downward. The increase in soluble sodium percentage from the 2A horizon into the 1A horizon reflects capillary rise of water as the surface soil dries. The decrease in calcium plus magnesium and the increase in sodium indicate that ion exchange is primarily re- sponsible for the increase. The gradual increases in SOLUBLE SODIUM PERCENTAGE GEOLOGICAL SURVEY RESEARCH 1961 TABLE 1.—Distm'bu tion of ions with depth in soils INCHES BELOW SURFACE so I I I I l l 1 | 1 FIGURE 22.1.——Changes in soluble sodium percentage (SSP) with depth through a residual coarse-silt loam soil near Palo Alto, Calif. (curve A), and an alluvial medium-silt loam soil near Fort Apache, Ariz. (curve B). Numbers and letters to left of curves designate soil horizons. soluble sodium percentage to the base of the B horizon and the little corresponding increase in total ion concentration reflect downward movement of water and frequent flushing. The increases in soluble sodium percentage are attributed primarily to ion exchange. The slight accumulation of calcium plus magnesium at the base of the B horizon reflects some Alluvial medium-silt loam soil near Fort Apache, Ariz. Residual coarse-silt loam soil near Palo Alto, Calif. Extract from saturated Extract from saturated Depth sell paste Depth 5011 paste ‘ below soil (Milli-equivalents per liter) below soil (Milli—equivalents per liter) surface surface __-_H_‘_____,___ (Inches) (Inches) 1 (“21+ Mg Na Na Total 6.69 0.97 0.31 4.31 3.90 .78 .30 5.18 3.16 .97 .30 70 2_30 .97 .38 58 2.17 1.19 46 66 1.83 1.23 «16 ~16 3.81 ~11 7.55 55 11.10 2 22 17.10 3 70 accumulation of moisture above the more porous cal- careous C horizon; but there is no evidence of capil- lary rise from this zone of possible moisture accumu- lation. The top of the C horizon is apparently the depth to which water frequently penetrates and is retained at or near the field storage capacity. Movement of some moisture down through the C horizon by capillarity is reflected by the sharper increase in soluble sodium percentage with depth. This sharper increase indicates precipitation of cal- cium from solution and is apparently the result of both ion exchange and salt solubility. The increase in soluble sodium percentage in both directions from the top of the B horizon reflects capillary rise from accumulated moisture above the impeding B21. hori- zon and some movement of water down through the impeding B2,, horizon. The accumulation of salts but no increase in soluble sodium percentage reflect the entrapment and evaporation of accumulated water at the impeding zone. REFERENCES Gardner, R., Whitney, R. S., and Kezer, A., 1957, Slick spots in Western Colorado soils: Colorado State College Exp. Sta. Tech. Bull. 26, p. 1—13. Kelley, W. P., 1948, Cation exchange in soils: New York, Reinhold Pub. Corp., 144 p. Rible, J. M., and Davis, L. E., 1955, Ion exchange in soil columns: Soil Science, V. 79, p. 41—47. 5? 4:. .’4 f" SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 13—47 23. COMPRESSION 0F ELASTIC ARTESIAN AQUIFERS By S. W. LOHMAN, Denver, Colo. The concepts of the occurrence of water in artesian aquifers have changed considerably in the last 35 years. Artesian aquifers formerly were considered .to have only the properties of conduits for conduct- ing water from the recharge areas to the points of discharge (such as wells) and to have no property of storage, as now known. Confining beds were re- garded as impermeable, whereas we now know that an artesian aquifer may be confined by a relatively impermeable stratum or simply by a stratum having permeability lower than that of the aquifer. Only wells that flowed at or above the land surface were considered artesian by many earlier workers. Now artesian wells are considered by most authorities to be those in which the water is confined under pres- sure beneath a relatively impermeable stratum or a stratum of lower permeability than the aquifer, and in which the water rises above the point at which it is first found in drilling. Meinzer and Hard (1925, p. 90—93) were the first to recognize that an artesian aquifer does not per- form like a rigid system, but as one having volume elasticity and hence variations in storage capacity with changes in the internal buoyant force due to changes in artesian head. The evidence that a large part of the water discharged from artesian wells came from storage by compression of the aquifers with loss of artesian head led to Meinzer’s classic theory of the compressibility and elasticity of arte- sian aquifers (1928). It has long been recognized that two types of com- pression are involved: elastic compression of elastic media, such as a clean sand or sandstone; and plas- tic deformation of bodies, lenses, or beds of clay in or adjacent to the aquifer. The amount of elastic compression, with which the remainder of this paper is chiefly concerned, is small but nevertheless signifi- cant. The amount of plastic deformation of clay bodies may be rather large, and has caused sub- sidence of the land surface of from a few feet to several tens of feet where artesian water or oil has been withdrawn in large quantities. (See Gilluly and Grant, 1949; Winslow and Doyel, 1954; Poland and Davis, 1956; and the report of the Inter-Agency Committee on Land Subsidence in the San Joaquin Valley (1958); see also papers in this volume by Poland, Art. 25; Lofgren, Art. 24; Miller, Art. 26). The next important step in our understanding of the manner in which artesian aquifers release water from storage was the development by Theis (1935), through analogy with the mathematical theory of heat conduction, of an equation for the non-steady- state flow of ground water through permeable media to a discharging well, which is Q 00 8 = 4,7 ,23 du (1) m in which 3 is the drawdown in water level at dis- tance r from a well discharging at constant rate Q from an extensive homogeneous and isotropic acqui- fer having a coefficient of transmissibility T (perme— ability times thickness) and a coefficient of storage S after a period of discharge t. This important equa- tion, which for the first time introduced the elements of time (t) and coefficient of storage (S), has be- come the foundation of quantitative ground-water hydrology. The coefficient of storage (S), which is a dimensionless constant, was defined by Theis (1938, p. 894) as “ * * * the volume of water, meas- ured in cubic feet, released from storage in each column of the aquifer having a base 1 foot square and a height equal to the thickness of the aquifer, when the water table or other piezometric surface is lowered 1 foot.” Thus, if in an artesian aquifer having a coefficient of storage of 2 X 10—4 (0.0002) the head is lowered 400 feet in an area of one square mile (about 2.79 X 107 ftz), more than 2.23 X 106 ft3 of water is released from artesian storage. Jacob (1940, p. 575, 576) pointed out that the release of water from artesian storage involves not only compression of the aquifer but also elastic ex- pansion of the contained water, and that the com- ponents of the coefficient of storage may be defined by 1 b in which S is the coefficient of storage; 7 is the specific weight of water (62.4 lb ft-‘i/144 in‘-’ ft—‘-’ = 0.434 1b in‘2 ft—l) ; 6 is the porosity of the aquifer; m is the thickness of the aquifer, in feet; E”. is the bulk modulus of elasticity of water (3X 105 lb in“2) ; b is the effective part of unit area of the aquifer that B—48 responds elastically 1; and E is the bulk modulus of elasticity of the aquifer. It is convenient to use the reciprocal ,8 in place of WEL’ the value of ,8 being 3.3 X 10-.. in? 1b". " By combining Hooke’s Law of elasticity with equa— tion (2), I shall propose an equation for determining the amount of elastic subsidence or compression from other known factors. Hooke’s Law states that, within the elastic limit, strain is proportional to stress. In notation convenient to the problem, Hooke’s Law may be written (3) in which Am is the change (reduction) in thickness of the aquifer (amount of elastic subsidence), in feet; m and E, are as defined for equation (2) ; and A1) is the change (reduction) in artesian pressure, in lb ft‘g. Dividing both sides of equation (2) by y, assum- ing 1) to be unity, substituting the reciprocal ,8 for m Am 2 #Ap 8 ——, and expanding, equation (2) becomes Ell‘ S m —: 6m 4 y B + E. ( ) Equation (3) may be written m Am K—A—p (5) . Combining equations (4) and (5) and solving for Am gives the desired equation Am = A1) (S/y—omfi) (6) Thus, in an elastic or reasonably elastic artesian aquifer, for which S is known from a pumping (Theis, 1953) or flow (Jacob and Lohman, 1951) test, 0 is known from core or sample tests, m is known from a driller’s log or electric log, it is pos- sible to compute from equation (6) the amount of elastic subsidence of the land surface (compression of aquifer) Am, for a given regional decline in arte- sian pressure A1). For example, although studies of the Denver artesian basin are not yet completed, preliminary information (George H. Chase, U.S. Geological Survey, written communication, Jan. 23, 1961) indicated that average values for wells in the basal sandstone and conglomerate of the Arapahoe formation (Upper Cretaceous) in the Denver metro- 1 In an aquifer composed of uncemented granular material the value of b is unity. In a solid aquifer, as a limestone having tubular channels, b is apparently equal to the porosity. The value of b for a sandstone doubtless ranges between these limits, but in the development that follows, a value of unity has been assumed. GEOLOGICAL SURVEY RESEARCH 1961 politan area are about: S : 5 X 10", 0 = 0.33, m : 200 ft, and Ap : 260 1b in*'-’ (600 ft decline in head). Using equation (6) ‘-’ Am : 2.6 X 1021bin—2 [(2.31 ft lb-1 in2) (5 x 10—4) — (0.33) (2>< 102 ft) (3.3 x 10451112150] 2 2.6 x 10'-’1bin5'~‘ . ' [11.55 ><'10-* ft 15—1 in2 — 2 >< 10-4 ft 151 in9] : 0.25 ft USing the above value of Am, and other known factors, equations (3) or (5) may be solved for E,, which is found to be about 2.1 x 10" lb in—‘-’—a rea- sonable value for a sandstone or conglomerate. The studies now in progress by Mr. Chase will include a comparison of the total computed elastic compression of this and overlying and underlying artesian aquifers with the total subsidence of the land as indicated by old and new leveling by the U. S. Coast and Geodetic Survey. ‘ It should again be stressed that equation (6) gives only the elastic compression or subsidence, and that the greater subsidence that has occurred in many areas is due to plastic deformation of asso- ciated clay. REFERENCES ‘ Gilluly, James, and Grant, U. S., 1949, Subsidence in the Long Beach Harbor area, Calif.: Geol. Soc. America Bull., v. 60, p; 461—529, 28 fig. Inter-Agency Committee on Land Subsidence in the San Joaquin Valley, 1958, Progress report on‘land-subsidence investigations in the San Joaquin Valley, Calif., through 1957; Sacramento, Calif., 160 p., 45 pls. Jacob, C. E., 1940, On the flow of water in an elastic artesian aquifer: Am. Geophys. Union Trans, pt. 2, p. 574—586, .4 figs. Jacob, C. E., and Lohman, S. W., 1952, Nonsteady flow to a well of constant drawdown in an extensive aquifer: Am. Geophys. Union Trans, v. 33, p. 559—569, 9 fig. Meinzer, O. E., 1928, Compressibility and elasticity of artesian aquifers: Econ. Geology, v. 23, p. 263—291. Meinzer, O. E., and Hard, H. H., 1925, The‘artesian water supply of the Dakota sandstone in North Dakota, with special reference to the Edgeley quadrangle: U.S. Geol. Survey Water—Supply Paper 520—E, 1p. 73—95, pl. 6, '7, fig. 7, 8. Poland, J. F., and Davis, G. H., 1956, Subsidence of the land surface in the Tulare—Wasco (Delano) and Los Banos- Kettleman City area, San Joaquin Valley, Calif.: Am. Geophys. Union Trans, v. 37, no. 3, p. 287—296, 12 figs. Theis, C. V., 1935, The relation between the lowering of the piezometric surface and the rate and duration of dis- charge of a well using ground-water storage: Am. Geophys. Union Trans. 16th Ann. Mtg., p. 519—524, 2 figs. 211: is convenient to use the reciprocal of 7 (0.434 lb in‘2 it“), which is 2.31 ft lb‘1 in”. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 Theis, C. V., 1938, The significance and nature of the cone of depression in ground-water bodies: Econ. Geology, v. 33, p. 889—902, 2 figs. B—49 Winslow, A. G., and Doyel, W. W., 1954, Land-surface sub- sidence and its relation to the withdrawal of ground water in the Houston-Galveston region, Texas: Econ. Geology, v. 49, p. 413—422. 5% 24. MEASUREMENT OF COMPACTION OF AQUIFER SYSTEMS IN AREAS OF LAND SUBSIDENCE By BEN E. LOFGREN, Sacramento, Calif. Work done in cooperation with the California Department of Water Resources Land subsidence affects an area of more than 2,500 square miles in the San Joaquin Valley, Calif, and is the result of compaction of unconsolidated alluvial and lacustrine deposits as ground-water levels are lowered by heavy pumping. The subsidence occurs in areas where the aquifers are confined or semicon- fined. Twenty specially designed compaction re- corders have been installed in the areas of maximum subsidence. Two to 5 years of records show that compaction measured by recorders is directly related to changes in water level, and is approximately equal to the surveyed subsidence of the land surface. In areas of maximum subsidence, ground-water levels show a general downward trend, and sub- sidence rates range from 0.4 to 1.5 feet per year. In these areas, 1 foot of subsidence has been observed for each 10 to 25 feet of water-level decline. Com- paction of the unconsolidated deposits takes place as the artesian pressure decreases, thus transferring more of the overburden load to grain-to-grain con- tacts of the aquifer. The compaction is due chiefly to a nonelastic rearrangement of the grains of the deposit and results in a permanent decrease in volume. A small part of the compaction is elastic, and samples tested in the laboratory for consolida- tion show minor rebound when unloaded. However, rebound or expansion of the aquifer system has not been observed in the field measurements. EQUIPMENT A special type of recorder is being used to measure the rate and magnitude of compaction occurring at depth. As shown in figure 24.1, the assembly con- sists of a heavy weight emplaced in the formation below the bottom of a well casing, with an attached cable stretched upward in the casing and counter- Recorder Sheaves Metal table on concrete platform Cable clamp in 50-lb increments Cribbed pit Well casing Plastic—coated cable, lxla-inch, stranded 4/2.. Anchor weight Open hole 200 to 300 lbs—2"" FIGURE 24.1.—Diagram of compaction-recorder installation. weighted at the land surface to maintain constant tension. A monthly recorder mounted over the open casing is used to measure directly the amount of cable that appears above the casing as subsidence occurs. At the land surface it appears as if the bottom-hole weight is rising; actually, the land sur- . B—50 GEOLOGICAL SURVEY RESEARCH 1961 face is settling with respect to the bottom-hole weight. The success of this method and equipment de- pends largely on the elastic characteristics of the cable under tension. After considerable experi- mentation, a specially manufactured 1/3-inch, stain- less steel, 7 X 7 stranded, plastic—coated cable was selected, and seems to meet the rigorous require- ments very well. Ball-bearing sheaves are used to reduce the frictional drag of the system. Compaction recorders have been installed in un- used irrigation wells and in specially drilled wells. At most sites, the bottom weight is placed in an open hole 15 to 25 feet below the bottom of the well casing so that measurements of vertical shortening are independent of the casing. At several locations in the San Joaquin Valley, compaction recorders have been installed in two or more closely spaced wells. Bottom-hole weights in these wells are placed at different depths so that the compaction occurring at different depth intervals can be computed. Water-level recorders are also generally installed in or near the compaction-re- corder well to record fluctuations and trends of ground-water levels as compaction continues. RESULTS A compaction recorder of the type shown in figure 24.1 installed in well 19/17—35N1 has been measuring the rate of compaction in the upper 2,000 feet of unconsolidated alluvial deposits near Huron, Cali- fornia. Subsidence of nearby bench mark B 889 has been determined by periodic leveling traverses of the U. S. Coast and Geodetic Survey. In addition, . the changes in hydraulic support in the underlying artesian aquifer system have been determined by frequent water-level measurements in well 19/18— 27M1. The correlation between subsidence of the surface bench mark, vertical compaction, and water-level fluctuation is shown in figure 24.2. The water level in well 19/18—27M1 fluctuates 50 feet or more each year in response to heavy pumping in the area, and has declined about 40 feet during the 4.8-year period \ 358 356 COMPACTION, IN FEET m >—- o (A, Land subsidence at bench mark 8889 Compaction in well 19/17—35 N1 \ 354 \ BENCH—MARK ALTITUDE, IN FEET 352 340 n E360 \\ A /~\ A A / \ /\ I-x E380U\/\/\VA/\/\/ /\/\ V V V V V / \/ \ “assassin“? - U \ /\ 420 V 1956 1957 1958 1959 1960 FIGURE 24.2.—Graph showing measured subsidence, compaction, and water-level change near Huron, Calif. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—51 shown on the graph. This water-level decline has resulted in a measured compaction of 3.8 feet within the 2,000-foot depth interval of the compaction re— corder, and a total subsidence of the land surface of 4.6 feet. Thus, subsidence near Huron is con— tinuing at a rate of 0.96 foot per year, and 1 foot of subsidence has occurred for each 10 feet of water- level decline. The compaction that occurred in the upper 2,000 feet of deposits during the 4.8-year period represented 82 percent of the total subsidence, suggesting that 18 percent, or 0.84 foot of compac- tion, occurred in the deposits below 2,000 feet. This assumption is reasonable, because nearby wells with- draw water from below 2,000 feet. COMPACTION RECORDERS 16H3 16H4 16H2 TjfiflV/sV/fiT/s g SW5 200 — I orcoran clay member f Tulare formation 400 ; }_ __ LIJ LJJ LI. Z . "Z 600 ”—Upper confined aquifer E 0. Lu 0 800 —- Lower confined aquifer 1000 —— i Approximate base of aquifer A. RELATION OF MULTIPLE RECORDERS TO THE HYDROLOGIC UNITS Inspection of figure 24.2 shows that each major change in hydraulic support, as indicated by the hydrograph of well 19/18—27M1, is reflected in the compaction graph. During periods of rapid water- level decline, compaction occurs at a maximum rate. Conversely, during periods of rising water levels, the compaction rate declines. No expansion has been detected by the compaction recorder during periods of water-level rise. Figure 24.3 A is a diagrammatic cross section through an area of active subsidence near Oro Loma, Calif. The relative positions of the depth anchors of the three compaction recorders operating at this site are shown in relation to the principal hydrologic COMPACTION RATE, ft x 1074/ft/yr O 1 2 3 4 5 6 7 I I | I I I Nov. l,1958,to Nov.1,1959 M Nov. 1, 1959, to Nov. 1, 1960 §_ 16H3 f___.......__...| 16H4 ‘ ‘ Ito-ooouuooonuooo- 'Q 16H2 B. MEASURED COMPACTION RATE OF DEPOSITS IN THREE DEPTH ZONES FIGURE 24.3.—Compaction rates near Oro Loma, Calif., as measured by three compaction recorders. A, Relation of multiple recorders to hydrologic units; B, measured compaction rate of deposits in three depth zones. B—52 units. Recorder 16H3 measures the total compac- tion occurring between the surface and the anchor at 350-foot depth. Similarly, recorders 16H4 and 16H2 measure the compaction occurring between the surface and their respective 500-foot and 1,000- foot anchor depths. By comparing the record of any two recorders, the magnitude and rate of com- paction occurring in each depth zone are. obtained. Figure 24.3 B shows the rate of compaction that occurred in each of three depth zones for two periods of recording. For comparison, these rates have been converted to unit values and represent the average amount of vertical shortening that occurred in each foot of thickness each year. The compaction rate in GEOLOGICAL SURVEY RESEARCH 1961 the 350- to 500—foot depth zone decreased greatly during the second year of record. From November 1, 1959, to November 1, 1960, 0.014 foot of compaction occurred in the 0- to 350- foot depth zone (0.40 ><10—4 ft/ft/yr), 0.016 foot of compaction occurred in the 350- to 500-foot depth zone (1.07 X 10—4 ft/ft/yr), and 0.292 foot of com- paction occurred in the 500- to 1,000-foot depth zone (5.84 X 10—4 ft/ft/yr). The total 0.322 foot of com- paction measured by the 1,000 foot recorder approxi- mately equaled the amourt of subsidence of a nearby Coast and Geodetic Survey bench mark. These measurements suggest that during this 1-year period, little or no compaction was occurring within the unconsolidated deposits below 1,000 feet. 61‘ 25. THE COEFFICIENT OF STORAGE IN A REGION OF MAJOR SUBSIDENCE CAUSED BY COMPACTION OF AN AQUIFER SYSTEM By J. F. POLAND, Sacramento, Calif. Meinzer (Meinzer and Hard, 1925) was the first to conclude that the water discharged by wells tap— ping an artesian aquifer (the Dakota sandstone) had been derived largely from storage. He reasoned that water withdrawn from storage was released by compression of the aquifer. Subsequently Meinzer (1928) considered release from storage by expansion of the water, described evidence for the compressi— bility and elasticity of artesian aquifers, and stated (p. 289) that “* * * artesian aquifers are apparently all more or less compressible and elastic though they differ Widely in the degree and relative im- portance of these properties.” ' Following development in 1935 of Theis’ equation for non-steady-state flow of water to a discharging well, Theis (1938, p. 894) defined the coeflicient of storage as “ * * * the volume of water, measured in cubic feet, released from storage in each column of» the aquifer having a base 1 foot square and a height equal to the thickness of the aquifer when the water table or other piezometric surface is lowered 1 foot.” Shortly thereafter Jacob (1940) postulated that when water is removed from and pressure is de- creased in an elastic artesian aquifer, stored water is derived from three sources: (a) expansion of the confined water, (b) compression of the aquifer, and (c) compression of the adjacent and included clay beds. He concluded that the third source is probably the chief one in the usual case. He stated (p. 574) “ * * * that because of the low permeability of the clays (or shales) there is a time-lag between the low- ering of pressure within the aquifer and the appear- ance of that part of the water which is derived from storage in those clays (or shales).” To avoid mathe- matical complications, however, he assumed that release of stored water from the clay beds is in- stantaneous. He defined the coefficient of storage in terms of the three sources of water, as In this equation S is the coefficient of storage; 7 is the specific weight of water (0.434 lb/in2/ft); 0 is the porosity of the aquifer; m is the thickness of the acquifer, in feet; E,..1 is the bulk modulus of elasticity of the water (3 X 105 lb/in2) ; b is the proportion of the plane of contact between the aquifer and the con- fining layer over which the hydrostatic pressure is effective (unity for an aquifer composed of un- cemented granular material) ; E,. is the bulk modulus of elasticity of the'aquifer matrix; EL. is the modulus of compression of clay beds; and c is a dimensionless (1) 1 5, the reciprocal of EM” is 3.3 X 10-” in2 lb". SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 quantity that depends largely on the thickness, con- figuration, and distribution of the intercalated clay beds. Elsewhere in this volume Lohman (Art. 23) briefly reviews the development of the concepts of the oc- currence of water in artesian aquifers beginning with Meinzer’s classic work, and derives an equa- tion fOr determining the amount of elastic compres- sion of artesian aquifers from known declines in artesian pressure and known hydrologic properties of the aquifers. Lohman’s equation (Art. 23, this volume) is expressed in the form Am 2 A}? (3/7 — 0mm. (2) in which Am is the reduction in thickness of the aquifer (amount of elastic compression), in feet, and A20 is the reduction in artesian pressure in lbs/ft". The other terms are as defined for equation (1). Loh- man’s equation (2) affords a means of evaluating the second component of equation (1), ymb/E,, when E, is not known. In areas where intensive ground-water develop- ment has drawn down the artesian head substantially ' (a hundred to several hundred feet) in highly com- pressible confined aquifer systems containing many clay interbeds, major subsidence of the land surface has occurred. For example, land subsidence from this cause has reached 2 to more than 20 feet in parts of the San Joaquin Valley (see Art. 24 by Lofgren and Art. 26 by Miller) and 9 feet in the Santa Clara Valley, both in California, and several feet in the Houston-Galveston area in Texas (Wins- low and Wood, 1959). The subsidence probably is caused almost wholly by compaction of the inter- calated and confining beds of clay, silty clay, and clayey silt, both by plastic deformation and me- chanical rearrangement of grains, and to that ex- tent is inelastic and permanent. In such aquifer systems the water taken from storage as defined by the coefficient of storage derived from short—term pumping tests may represent a very small part of the water actually removed from storage. APPLICATION TO THE LOS BANOS-KETTLEMAN CITY AREA Subsidence in the Los Banos-Kettleman City area on the central west side of the San Joaquin Valley (for location see map in Art. 26 by Miller) extends over 1,100 square miles and ranges from 1 to 22 feet. In most of this area, about all the subsidence is known to be caused by compaction of the confined aquifer system (see Art. 24 by Lofgren). B—53 We can compute approximate values for the com- ponents of the coefficient of storage in equation (1) for an example in the Los Banos-Kettleman City area. Average values used for the confined aquifer system are as follows: ,coefl‘icient of storage from short-term pumping tests about 1 X 10‘“, 0 = 0.4, m = 700 feet (aquifer thickness, excluding for this example the clayey interbeds aggregating about 300 feet in thickness), and A10 2 130 lb in—2 (300 feet decline in head). The first element of equation ( 1), the component of S due to elastic expansion of the water (identified here as S1) is yfimfl. S1 = (0.434 lb in‘2 ft‘l) (0.4) (700 ft) (3.3 X 10411121104) = 4 X 10'4 The elastic compression of the aquifer (elastic subsidence of the land surface) can be computed from equation (2), using the S obtained from short- term pumping tests, as follows: Am 2 130 lbs in—2 [(1 X 10‘3)/(0.434 lb in *3 ft‘l) — (0.4) (700 ft) (3.3 X 10—6 in2 lb‘1)]= 0.18 ft Thus, the second component of S in equation (1), identified here as $3, is the elastic compression di- vided by the artesian-head decline or 0.18 ft/300 ft = 6 X 10“. The component of storage derived from compac- tion of the clayey interbeds and confining beds (S3) can be estimated approximately from the gross sub- sidence of the land surface. In this area, the ratio of subsidence to head decline ranges about from . 1/10 to 1/25. If we use a ratio of 1/20 (subsidence z 15 feet for 300 feethof head decline), then the component of storage derived from compaction (both elastic and inelastic) of the clayey sediments is 15 ft — 0.18 ft 300 ft Summing the three components, S, + Sz + Sg, gives a long-term unit storage yield of 0.051. Thus, S3, the stored water released by compression or com- paction of the clayey beds, is about 50 times as great as the water released by elastic expansion of the water and elastic compression of the aquifer (com- ponents S, and $2). In other words, in this example, the coeflicientof storage derived from a short-term pumping test gives ,a volume only about one-fiftieth that of the long-term (15 to 25 years) yield from storage. 9 M: 0.05 or 5 x 10—2 B—54 GEOLOGICAL SURVEY RESEARCH 1961 This is an extreme example because it is computed for one of the most compressible aquifer systems for which data are now available. However, it serves to emphasize that the storage derived from compac- tion of the clayey interbeds and confining beds may be many times as great as that derived from elastic expansion of the water and elastic compression of the aquifer. Moreover, this component, 83, is a variable. The stored water yielded by the clayey beds would be large only during the first decline of artesian pres- sure. If the pressure subsequently recovered to (or near to) the initial conditions, and then was drawn down again through the same interval, the cem- pression of the clayey beds, if mostly preconsolidated during the first drawdown phase, would be only a small fraction of that in the first phase of pressure decline, probably less than 10 percent. REFERENCES Jacob, C. E., 1940, On the flow of water in an elastic artesian aquifer: Am. Geophys. Union Trans. let Ann. Mtg., pt. 2, p. 574—586, 4 figs. Meinzer, O. E., 1928, Compressibility and elasticity of artesian aquifers: Econ. Geology, v. 23, p. 263—291. Meinzer, O. E., and Hard, H. A., 1925, The artesian water supply of the Dakota sandstone in North Dakota, with special reference to the Edgeley quadrangle: U.S. Geol. Survey Water-Supply Paper 520—E, p. 73—95, pls. 6—7, figs. 7—8. Theis, C. V., 1935, The relation between the lowering of the piezometric surface and the rate and duration of dis- charge of a well using ground-water storage: Am. Geo- phys. Union Trans. 16th Ann. Mtg., p. 519—524, 2 figs. Theis, C. V., 1938, The significance and nature of the cone of depression in ground-water bodies: Econ. Geology, v. 33, p. 889—902, 2 figs. Winslow, A. G., and Wood, L. A., 1959, Relation of land sub- sidence to ground-water withdrawals in the upper Gulf Coast region, Texas: Am. Inst. Mining Metall. Petroleum Engineers Trans., v. 214; Mining Engineering, p. 1030- 1034. 5% 26. COMPACTION OF AN AQUIFER SYSTEM COMPUTED FROM CONSOLIDATION TESTS AND DECLINE IN ARTESIAN HEAD By R. E. MILLER, Sacramento, Calif. In the parts of the San Joaquin Valley shown on figure 26.1, the land surface has been subsiding at rates up to 1.5 ft/yr owing to large withdrawals of artesian water from poorly consolidated late Ceno- zoic sediments. By refining a method outlined by Gibbs (1960), the compaction in the confined aquifers is being computed at selected core-hole sites in the San Joaquin Valley. The method of computation is based upon Terzaghi’s theory of consolidation (1943, p. 266—267), using the results of one-dimensional consolidation tests made upon core samples of the aquifer system, and the decline in artesian head that has occurred. An extension of this technique can be used to predict future subsidence. COMPUTATION OF AQUIFER COMPACTION The computation of aquifer compaction at core hole 12/ 12—16H1 in the Los Banos—Kettleman City area in the western part of the San Joaquin Valley (fig. 26.1) is a typical example of the method being used in the present studies. In this area there has been no decline in the water table, but intensive pumping from the confined aquifer system has. caused a substantial drawdown of artesian head. The procedure for making the computations was as follows: 1. The upper and lower limits of the confined aquifers were determined from the electric logs of nearby wells. ' 2. Then, as shown in figure 26.2, the aquifer and overburden is divided into sufficient segments so that each segment could be represented by a single consolidation test typical for that segment. 3. The artesian head of the confined aquifers was determined from the static levels in nearby wells and converted into pounds per square inch. The decline in aquifer pressures was estimated for the aquifer system for the period 1937—59 using the static-level records of the wells for previous years. 4. The overburden load on the aquifers in pounds per square inch was computed from the wet unit weight of the core samples. There has l SHORT PAPERS IN THE GEOLOGIC AND H‘NDROLOGIC SCIENCES, ARTICLES 1-146 City area 100 MILES FIGURE 26.1.——Areas of land subsidence in the San Joaquin Valley, Calif. been no decline in the water table in this area between 1937 and 1959. This means that no compaction occurred in segments 1, 2, and 3 during this period and that there was no de- crease in overburden load on the confined aquifers owing to dewatering of the sediments above the water table. 5. The effective load on the top segments of the confined aquifers was computed for the periods for which the aquifer pressures had been de- termined by subtracting the aquifer pressure from the bulk weight of the aquifer overbur- den. The maximum load that could occur would be when the artesian pressure is zero and the full weight of the overburden bears on the aquifer. 6. One-dimensional consolidation tests were made on the core samples of the aquifer system for the maximum load range that could occur in the aquifers. These tests were made in the Earth Laboratory of the Bureau of Reclama- tion at Denver, Colo. An increase in loading results in a decrease in the void ratio of the sample tested. Clays tend to consolidate more under load than sands, but not as rapidly. B—55 7. The compaction occurring in each segment of an aquifer system can be computed for any speci- fied aquifer pressure decline if the effective load change on the segment can be determined. In determining the effective load on the seg- ment, the buoyant weight of any overlying aquifer segments is added to the effective weight of the overburden load. The aquifer pressures at the core-hole site are shown in figure 26.2 and the effective loading on each aquifer segment is listed in table 1. As illustrated in figure 26.2, two confined aquifers are present in this area. The prin- cipal aquifer is the lower one. Pumping from this aquifer was locally decreased shortly after 1953, owing to the availability of surface water from a nearby canal. Consequently the static levels of wells perforated in the lower aquifer were lowest in 1953 and have shown a slight amount of recovery since that time. The great- est effective load on the lower aquifer was in 1953, therefore, and the load at that time was used as a maximum for computing compaction in the lower aquifer. In the upper aquifer, which is tapped by only a few domestic wells, there has been a small but steady decline in static level between 1937 and 1959. 8. The compaction due to the load change on each segment of the aquifer system was computed from the void-ratio change which was deter- mined graphically from the extension of the straight-line part of the one-dimensional con- solidation curves. Compaction was computed by the equation _ 61 ‘ 63 Ali — ——1 + e] h in which Ah 2 compaction, in feet; 61 : initial void ratio; e._. : void ratio after loading, and h, : thickness of aquifer segment, in feet. The ultimate compaction determined for the confined aquifers as a result of the change in artesian pressure from 1937 to 1959, and the part of that compaction computed to have occurred by 1959 are shown in table'l. 9. A complicating factor that must be considered is the time lag of compaction. In segments of the aquifer that have very low permeability, years or even decades might be required before enough water is displaced so that all of the computed compaction can occur. The time re- quired for the computed compaction to be B—56 GEOLOGICAL SURVEY RESEARCH 1961 SELF VECTORS SHOWING o POTENTIAL RES'ST'V'TY SEGMENTS DESCR'PT'ON PRESSURE—LOADING DISTRIBUTION Miilivolts Ohm-meters (t 2'5 3? O is 30 OVERBURDEN LOAD ON } <. ARTESIAN AQUIFERS 100 I , 1 OVERBURDEN , (Silt, clay. and some sand) 400 PS' 200 % g 300 644 psi ________ i“ 2 _______ 3 400 i . 4 UPPER CONFINING CLAY (Diatomaceous) I— _ _ .. ._ _ __ _ _ LLJ E 5 500 m a -------- N g 1' 6 3 n *— H E ________ UPPER ARTESIAN D ———————— 7 AQUIFER 145 psi - ' 8 (Fine sand, silt. and clay) 169 DSi. 600 , j E 9 ARTESIAN PRESSURE 700 / _______ 10 11 LOWER CONFINING CLAY ———————— 12 800 > 13 ,m _______ .\ '3 0') --c 14 2 15 LOWER ARTESIAN 206 psi 90° AQUIFER ——————— (Fine to coarse sand, 260 psi silt, and clay) 16 1000 ARTESIAN PRESSURE 17 FIGURE 26.2.——Logs and diagram of pressure-loading distribution for the aquifer system at core hole 12/12 Valley, Calif. ~16H1, San Joaquin SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 TABLE 1.——Efi'ective loading and compaction at core hole 12/12—16H1 computed for the period 1937—59 B—57 1 Effective load ) 1'ltimate ‘ (‘ompar-tion completed by 1959 Amount of Segment lifllevtive 7”, 7 WW“... 7 7 ,2, ,_____ .A compaction '-’ Wig“; 7,7, _,W,__ w_ residual number 'l‘hivkuoss load 1937 tl'eetl ‘ compaction (Sec fig, 26.2) (feet) (psi) 1 Lower aquifer. 1953 Upper aquifer. 1959 Percent Feet as of 1959 - .1_psi| 1 (psi) 1 (feet! 5 ............ 48 231 ................ 255 j 1 . 13 89 1 .00 0. 13 0 ............ ~15 247 ................ 271 ’ .50 100 50 .00 7 ............ 20 265 ................ 289 1 .52 100 .52 .00 8 ............ 25 272 ................ 200 . 10 100 .16 .00 9 ............ 87 284 ................ 308 . 76 26 . 20 56 10 ........... 24 323 ................ 347 . 12 100 . 12 .00 1 I ........... 38 33-1 ................ 358 .35 63 .22 . 13 12 ........... 24 38-1 438 ................ .28 100 .28 .00 13 ........... 52 395 449 ................ . 3-1 100 .34 . 00 14 ........... 32 410 473 ................ .31 100 .31 .00 15 ........... 71 433 487 ................ 1.08 100 1 .08 .00 10 ........... 69 4155 510 ................ .75 100 . 75 .00 17 ........... 160 495 5-19 ................ l . 74 100 1 .74 .00 Tota1.. ........................................................ 8.10 ............. 7.28 0.82 1 Pounds per square inch. 2 Compaction estimated to occur as result of artesian-head change, 19377-59. completed can be estimated from the consoli- dation coefl‘icient which is determined as part of the one-dimensional consolidation test. The equation given by Terzaghi and Peck (1948, p. 241) for computing the compaction time is Th‘~’ t in which t : compaction time, in years; T : time factor; h : thickness of aquifer segment, in feet; and C, : consolidation coefficient, in ftg/year. If drainage can take place from both top and bottom of the aquifer segment, (IL/2)2 is Used ‘in place of h? The time required for various percentages of compaction to be completed is not a linear relation, for the time depends upon T, which is a pure number nonlinearly related to the percent of compaction completed. Thus T : 1.0 for about 93 percent compaction, T : 0.2 for 50 percent compaction, and T : 0.0076 for 10 percent compaction. Compaction of the upper confining clay oc- curs by drainage into the underlying aquifer as a result of the downward pressure differen- tial. The time required forthis compaction to be nearly completed (about 93 percent) can be estimated from the preceding equation, using the values T : 1, h : 86 feet, and 0.. ’ : 0.92 ftg/yr for the load range of 200 psi to 400 psi. t_1><862 _ 0.92 : about 8,000 years Similarly, half of the compaction would be completed in about 1,600 years, but 10 percent of the compaction would be completed in only about 60 years. This would indicate that only a small amount of compactiomhas occurred in this confining clay segment during the rela- tively short period between 1937 and 1959. By this method the percent of compaction completed in each segment of the aquifer at core hole 12/12~16H1 was computed and is shown in table 1. Secondary consolidation ef- fects have not been considered in these ap- proximate computations of compaction. COMPARISON OF COMPUTED SUBSIDENCE TO MEASURED SUBSIDENCE Releveling of bench marks by the U. S. Coast and Geodetic Survey indicated that 7.8 feet of land- surface subsidence occurred in the vicinity of core hole 12/12—16H1 between 1937 and 1959. The total ultimate computed compaction of the aquifers due to pressure decline between 1937 and 1959 is 8.1 feet. The' part of this ultimate compaction computed to have occurred by 1959 for segments 5 through 17 (fig. 26.2) is 7.28 feet. In addition, the rate of com- paction of the upper confining clay (segment 4) has been calculated as approximately 0.01 foot per year. Thus, the total compaction computed to have oc- curred in segments 4 through 17 from 1937 to 1959 is 7.5 feet, compared to ameasured land-surface Esubsidence of 7.8 feet.i :The,‘ residual compaction B—58 estimated to occur after 1959 as a result of the de- cline in artesian pressure from 1937 to 1959 is 0.8 foot in segments 5 through 17. Additional compac- tion in the upper confining clay (segment 4) is esti- mated to continue at a rate of roughly 0.01 foot a year unless the artesian pressure in the upper arte- sian aquifer recovers appreciably. GEOLOGICAL SURVEY RESEARCH 1961 REFERENCES Gibbs, H. J., 1960, A laboratory testing study of land sub- sidence: The First Pan American Conference on Soil Mechanics and Foundation Engineering Proc., 1959, Mexico City, v. 1, p. 13—36. Terzaghi, Karl, 1943, Theoretical soil mechanics: New York, John Wiley & Sons, 510 p. Terzaghi, Karl, and Peck, R. B., 1948, Soil mechanics in engi- neering practice: New York, John Wiley & Sons, 566 p. 5% 27. DEVELOPMENT OF AN ULTRASONIC METHOD FOR MEASURING STREAM VELOCITIES By H. O. WIRES, Columbus, Ohio Work done in coperation with the US. Army Corps of Engineers and the California Depart‘m nt of Water Resources Continuous records of streamflow in tidal or back- water reaches are difficult to obtain by conventional methods because the velocity of flow is not a simple function of water-surface elevation. The number of such reaches in which flow records are needed is in- creasing as more streams are controlled by reser- voirs and as the flow in tidal reaches becomes in- creasingly important in the total development of water} resources. Continuous records of velocity would allow computation of flow at any time, and efforts have been directed toward development of instrumentation for that purpose. A system has been devised that utilizes the differ- ence in velocity of propagation of sound in the up- stream and downstream directions to measure the velocity of streamflow. In this system transducers are installed near each streambank at an angle 0 with the direction of flow as shown on figure 27.1. Ultra- sonic waves are generated and received at both in— stallations. The difference in travel time of the wave in the upstream and downstream direction is re- lated to the velocity of streamflow and this relation can be derived mathematically. A continuous wave transmission system using re- ceived-wave displacement as a measure of the dif- ference in travel time was first designed and con- structed under contract by Raytheon Manufacturing Company. After testing the system at several loca- tions and under many separate conditions it was concluded that phase stability requirements could not be achieved. The extre e fluctuations of phase and amplitude encountered could be ascribed to multipath interference phenomena due to such causes as thermal and energy gradients and boundary reflections. A second system has been devised, which elimi- nates the defects of the continuous wave transmis- sion system. The basic characteristics of the new system, which is known as the pulse repetition fre- quency (PRF) method, are: 1. Upstream and downstream sound velocities are measured simultaneously over a single acoustic path. 2. A transmitted pulse with a sharp leading edge is used to eliminate multipath effects. The first Z/z/Wigyz/g _L~ , ’ g I ”7/7/22; 17/742??? Flow . \ FIGURE 27.1.—Installation of trans ucers in a stream channel. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 arrived signal is used and any immediately fol- lowing signals are gated out. 3. Flow velocity is related to the mean of the dif- ferences between the downstream and , up- stream propagation velocities. A system having these characteristics is shown diagrammatically on figure 27.2. A 135- acoustic pulse is transmitted from the upstream transducer and received at the downstream transducer. The energy from this pulse activates a keying circuit and another 135- pulse is transmitted from the up- stream transducer. The 85- electro-acoustic circuit operates simultaneously with, and in the same man- ner as, but in the opposite direction from the 135- circuit. The two-pulse repetition frequencies (PRF) are fed into a computing circuit, the output of which is proportional to the difference frequency. It is easily shown that the difference frequency is proportional to the velocity of streamflow. Let: 1; = velocity of moving medium B—59 c : velocity of sound with no flow (1 : length of acoustic path 0 : angle between downstream acoustic path and downstream flow path Velocity of sound propagation downstream 012 : c + 1} cos 6 Velocity of sound propagation upstream 021 : c — 1) cos 0 The times of travel are L__.,d_ clguc + vcos0 Then : i d and tgl : -— 021 c — 7} cos 0 t12 : The pulse repetition frequencies, f12 and fgl, are given by the reciprocals of these equations and the velocity of the streamflow is d v‘Zcose (fig — 1‘21) The computing circuits consist of two PRF multi- pliers, two motor-driven amplifiers, a synchro-differ- Flow \ ? , ? // / / Transmitting, PRF: f2 / L9 receiving, and ‘0 keying circuits / /Oa 85kc / Q 4' #9/ / J ~/ / / \7 0 i‘" Velocity / / meter / Computing I circuits / / / / i / / / Transmitting, receiving, and 10 inch strip keying circuits chart recorder / 135‘“ PRF: f1 // FIGURE 27.2.—Diagram of the PRF system. B—60 ential, and a synchro-generator. The multipliers are used to bring the pulse repetition frequencies close to 60 per second. The synchro-differential subtracts the two frequencies, and the output of the synchro- generator is proportional to this difference fre- quency. The generator output is fed into a circuit which multiplies this signal by the constant d/(2 cos 0). This product voltage appears on a meter and is recorded on a 10-inch strip chart. The velocity of flow equation shows that, in addi- tion to the two pulse-repetition frequencies, it is necessary only to determine d and 9 to compute the river velocity. These two quantities are easily and GEOLOGICAL SURVEY RESEARCH 1961 1 accurately measured. As t e upstream and down- stream transmissions are sent simultaneously the effects of any fluctuations caused by changes in the acoustic properties of the water are eliminated. The PRF system has been installed on the Sacra: mento River at Sacramento, Calif. Several problems in the original design and peration of the equip- ment, such as selection of p per cable for adequate transmission, determination of automatic gain con- trol requirements, and prev ntion of extensive rec- ord blanking from occasion I missed pulses, have been resolved, and a record is now being obtained to be used for analysis of the method. 6% 28. PRELIMINARY, DESIGN OF AN ELECTRIC ANALOG OF LIQUID FLOW IN THE UNSATURATED ZONE By R. W. STALLMAN, Denver, Colo. The solution of hydrologic problems, in which the details of liquid flow through the unsaturated zone are significant, has been hampered by a lack of simple means for computing the relation between time, flow, moisture content, and space. Normally flow in the unsaturated zone is one— dimensional, nonsteady, and occurs approximately vertically. The differential equation relating the variables of liquid flow for this condition may be stated as %:h, 616: ah: _+7—+1]= is the porosity, 0, is the liquid content expressed as a fraction of the porosity, and t is time. The conductivity k, is a non- linear function of the liquid content of 0,; conse- quently it is very difficult to find mathematical solu- tions satisfying both equation (1) and the highly variable field boundary conditions at the upper and lower limits of the unsaturated zone. Philip (1955) devised an efficient iteration process for finding a solution to a form of equation (1) for continuous infiltration from the land surface. Subsequently Youngs (1957), by laboratory studies, demonstrated that Philip’s method gave accurate forecasts of flow ensuing from infiltration. Nelson (1960) recently determined nonsteady liquid drainage from initially saturated sediments by solving the differential equa- tions of flow using digital computing equipment. Youngs (1960) applied the capillary-tube hypothesis of unsaturated flow to calculate drainage from satu- rated media as a function of time. Use of Philip’s iteration process is limited to a hydraulically: homogeneous profile and increasing water content during infiltration from the land sur- face. Although digital computing equipment is capable of solving the problem regardless of com- plicating nonhomogeneities and variable boundary conditions, experience has indicated that the costs of. such solutions are generally higher than can be afforded in ordinary hydrologic investigations. In an effort to obtain a versatile and low-cost computing system for the study of liquid flow through the un- saturated zone, electric analog techniques for solving equation (1) were considered. The following de- scribes preliminary plans for an electric analog system believed capable of solving problems in one- dimensional vertical flow through nonhomogeneous profiles under a variety of boundary conditions. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 lO . . 1 . lO 8 - - 8 6 ' D 4 6 Z M C) :3 Q ‘5 f 1+ ' 1 1I- (\l I S «V x I; a“ 2 - a 2 O a L L, O O. . 2 . 1+ . 6 . 8 1 . O 9 .8 FIGURE 28.1.—Hydraulic characteristics of unsaturated porous media. For electrical simulation, equation (1) may be more conveniently written in the following form: : 0 62h; 310g kl ah: aahl [1+ az[az +1} D’ (2) 822 the liquid diffusivity of the . . <1> ad; in which D, _ 161—8sz , unsaturated porous media. Neglecting hysteresis, the curve of D, versus (9, may be obtained directly from curves of kl versus 6, and h, versus 0; charac- terizing the porous media. An example of a set of these curves is given in figure 28.1. Consider equation (2) as comprising three sep- arate terms, each defining a single component of flow accumulation at a point, z. The first gives the rate of change of storage for a hydraulically homo- B—61 2 vii/£32; A 522 522R I$510gk£ iah£+1 B 52 L62 ' ah ' tall ea_e \l/ IA: : \IB V \ L FIGURE 28.2.—Electrical currents analogous to terms in equation of flow. Model Static head reference (Bias) e- n+1——’; ea ‘Z i site '1: o -——o e+ FIGURE 28.3.—Schematic diagram of analog and bias circuits. B—62 GEOLOGICAL SURVEY RESEARCH 1961 Model “‘h n + 1 Summing em Z(n + l) Bias amplifier A H n + 1 e 2 3° r8 A? H on /o 0 Q}. S 3%? -4 log k ‘ Summing 1 .Q’» 53:9 versus h +1 amplifier r—.‘] . Q7 037 "I function F. [$0 5. ,0 A generator + 7 a) N C: J: I/O V 5 log k 5h Q I 2 2 x K :5“ T + 0 e 52 ‘ Z 1 go H E to I converter IB to node n Model S ‘ n ' 1 Summing Bias amplifier n - 1 em hi, (n - l) FIGURE 28.4.—Computer for determining In. geneous element, the second identifies variations due to hydraulic heterogeneity and gravity, and the third accounts for changes as a function of time and storage capacity. The electrical counterparts of these terms are currents (I ) added to a point in a resistive element, with a constant resistance (R) per unit length, as shown in figure 28.2. The continuous resistance element must be viewed as a series of finite elements because it does not appear practical to model I 1, and [C at each point along its length. Accordingly, a finite-difference approximation to equation (2) is represented by the electrical model shown in figure 28.3. A voltage divider at the right in figure 28.3 serves as a reference for static head conditions in the profile and for dynamic evaluation of k, and D; as the analysis proceeds. As can be shown by finite-difference techniques, IA to any node n in the model is simply the resultant of current flow from points 71 + 1 and n — 1. Simu- lation of I 1; is much more difficult. A schematic of a proposed circuit for calculating I 1, is given in figure 28.4. The output may be fed directly to node n. How- ever, to effect a solution, only the 6 versus I B con- verter (the last element in the circuit of figure 28.4) need be constructed at each node. By adding memory to this converter, it will be possible to switch the circuit of figure 28.4 continuously over the network of nodes, changing the value of I B at each pass. Use of such a switching arrangement would permit solving problems of one-dimensional flow with only one set of the equipment shown in figure 28.4. The third term of equation (2) may be simulated at each node by an electronic element whose capacity changes as a function of voltage at the node. The latter ele- ment is to be designed so that the capacity versus node-voltage curve is congruent with an appropriate curve of D, versus kl, such as the one shown in figure 28.1. Varying boundary conditions, in terms of either liquid head or flow rates, may be applied to both or only one end of the resistor elements and bias control. Analog construction is underway with the objec- tive of solving for drainage from homogeneous pro- ' SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 files; computed results Will be compared with labora- tory data already available in the U. S. Geological Survey Hydrologic Laboratory, Denver, Colo. Once these initial phases are completed, studies will be made of drainage from nonhomogeneous profiles. It seems that the basic analog plan described here can more easily be modified to account for nonhomo- geneities than other analytical techniques thus far considered. Nevertheless, the search for a more efficient analog system is being continued while de- velopment work on the above electric analog continues. 29. DIRECT-READING By I. S. MCQUEEN and C. One measurement that has been useful in selecting desirable water sources and in identifying the aquifer supplying a given well is specific conduc- tance, which is an indicator of the total dissolved solids in water. Laboratory analyses of water samples usually include this measurement. A con- ductivity bridge that could be used in the field would permit more rapid selection and identification of water sources, and would guide in the choice of sources for which more complete chemical analyses should be made. Available conductivity measuring equipment did not appear to be suitable for field use because of inconvenient operation, lack of sen— sitivity, or instability. Preliminary requirements for a suitable instru- ment include the following: (a) a range of 0 to 10 millimhos, (b) provision for temperature measure- ment and temperature compensation, (c) provision for use of a conductivity cell with a cell constant of 2 and for a limited range of adjustment for varia- tions between cells, (d) portability, (e) low power consumption, and (f) simplicity of use. The newly designed instrument described here fulfilled all these requirements and several that were subsequently proposed. The circuit'diagram for the completed bridge is shown in figure 29.1. B—63 REFERENCES Nelson, R. W., 1960, Ground water movement rates: Am. Geophys. Union Ground-Water Symposium, Pacific North- west Hydrologic Research Committee, Nov. 16, Portland, Oregon, oral presentation. Philip, J. R., 1955, Numerical solution of equations of the diffusion type with diffusivity concentration-dependent: Faraday Soc. Trans, v. 51, p. 885—892. Youngs, E. G., 1957, Moisture profiles during vertical infiltra- tion: Soil Sci., v. 84, p. 283—290. , 1960, The drainage of liquids from porous materials: Jour. Geophys. Res., V. 65, p. 4025—4030. CONDUCTIVITY BRIDGE R. DAUM, Denver, Colo. A transistorized oscillator supplies a 1,000-cycles- per-second signal for excitation and a small high impedance earphone is used to detect the null or balance point. The bridge measures either the re- sistance of a thermistor directly in ohms or the specific conductance of a water sample in millimhos by using a precision 10-turn variable resistor for the measuring arm and selected resistors for the ratio arms. The resistance of the measuring arm, using a 0- to 5,000-ohm variable resistor and a 10-turn microm- Jflgfl ohms, in which D is the dial reading (0.00 to 10.00). Then, with the operation selector switch S1, in position 2 and the bridge in balance, the following relationship holds: eter dial, is 1,000 D _ 600 2 Rth _ 1,200 1,000 D : Rm (1) means that when measuring resistance the dial in which R”, is the resistance of the thermistor. This reads directly from 0 to 10,000 ohms to the nearest 10 ohms. A thermistor with a nominal resistance of 2,000 ohms at 25°C is used to measure the temperature of B-64 GEOLOGICAL SURVEY RESEARCH 1961 I \R, 0— 5.000 J‘— —__ As reqwred Headphone 03 \_____ 1 2 3 1 sm- SleA R3 900 —r\— 1 R4 Rm {‘5 0—1.000m— 13K 11K ' 50A . 1 200A Temperature L1 ’ compensator — #4; R _ 6V— x 2 _ __ 2N45 0—200—A— —-——O-05 Cell constant R C 82 ; compensator Conductivity cell Oscullator V f K l3 2l1 Sl-B FIGURE 29.1.—Conductivity bridge circuit. solutions. A calibration curve for this thermistor these values in equation 2 and simplifying we find was obtained by laboratory measurements, so that the temperature of a solution can be obtained from this curve and the resistance readings. The tem-I perature-compensation dial on the bridge is set for this temperature, and the bridge then measures the conductivity adjusted toa standard temperature of 25°C. Temperature compensation was calibrated ac— cording to data of US. Salinity Laboratory 1. With the operation selector switch in position 3 and the bridge in balance, the following relation holds: 1,000 D _‘ 900 + R... 2(600 + Rte) _ R0 in which R,.. is the resistance of the temperature correction resistor, R... is the resistance of the cell constant compensating resistor, and R0 is the re- sistance of the conductivity cell in an unknown solution. By definition R. : K/EC, in which K is the cell constant and EC is the specific conductance 'of the solution. By substituting in the above for- mula we obtain: 1,000 D K/2 : EC (600 + RH.) (900 + R”) (2) With a cell constant of 2 and atemperature of 25°C, R". : 400 ohms and RH, : 100 ohms. Substituting 1 1,090 f, r: 600 + Rm where f, 2 temperature factors from table 15, p. 90, Agricultural Handbook No. 60, US. Dept. of Agriculture, and Rio is the resistance of the temperature-correction resistor. that: EC : D/1,000 Therefore, the dial reads directly in millimhos. The cell—constant compensation resistor was calibrated to keep the above equation in balance for cell con- stants of 1.8 to 2.2 3. Position 1 on the operations selector switch (Sl) was added to permit the use of a microdip cell with a cell constant of 0.1. The balance relation for this position is: 1,000 D K/2 : EC (600 + Rt.) 50 When the cell constant is‘0.1 the bridge reads di- rectly in millimhos. A sensitive balance was difficult to obtain on samples with high conductivity when using a micro- dip cell; therefore, a small transistorized amplifier (not shown in fig. 29.1) was built as a separate unit to sharpen the null point. A capacitor placed in parallel with the 600-ohm ratio arm of the bridge also sharpens the null point. The use of the micro- dip cell had been limited to the laboratory in the past. A series of 17 samples was measured in the field with this bridge. Repeat measurements were made 'M : 900 + R”. 2.2, Rec : 200 ohms. When K : 1.8, Rec : 0, and when K : SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 using a standard conductivity bridge. The measure- ments agree within about 2 percent. The standard deviation of the differences is 9.3 micromhos and B—65 students “t” for the paired data is 0.438 which in- dicates that there is no significant difference be- tween the pairs of analyses. 6% GEOLOGY AND HYDROLOGY 0F EASTERN UNITED STATES 30. AGE OF THE “RIBBON ROCK” 0F AROOSTOOK COUNTY, MAINE By LOUIS PAVLIDES, ROBERT B. NEUMAN, and WILLIAM B. N. BERRY, Beltsville, Md., Washington, D. C., and Berkeley, Calif. Discovery of Middle Ordovician graptolites estab- lishes the age of at least part of the “ribbon rock” in eastern Aroostook County, Maine. The “ribbon rock” (originally the ribbon limestone) was as- signed as a member of the Aroostook limestone in and north of the Presque Isle area (fig. 30.1) and classed as Middle Silurian in age (White, 1943, p. 129). Earlier, Twenhofel (1941, p. 169) suggested that these rocks might be of Late Ordovician age and possibly equivalent to similar rocks, such as the Whitehead formation of the Gaspé Peninsula in Quebec. Twenhofel’s suggested Ordovician age as- signment was followed by Boucot and others (1960) in a recent compilation of the geology of northern Maine. “Ribbon rock” in the Bridgewater area (fig. 30.1) is reassigned as a member of a new formation in a forthcoming report (Pavlides, in press). “Ribbon rock” underlies large parts of eastern Aroostook County (fig. 30.1) corresponding closely with the fertile potato-growing regions. The unit consists of beds of medium-gray to bluish-gray lime- stone several inches to several feet thick, separated by somewhat thinner layers of gray calcareous to greenish-gray noncalcareous slate. Limestone beds range in composition from relatively pure carbonate layers to argillaceous limestone and to calcareous siltstone. Some layers that are complexly deformed are found in sequence with beds having more regular stratification. Interbeds of graywacke, and lenses of graywacke and slate and of slate, are also included in the unit. Stratigraphic boundaries of the “ribbon rock” are poorly defined and little studied over broad areas; in parts of the Bridgewater area, however, the “ribbon rock” is underlain by graywacke and slate, and overlain, at places gradationally, by more argillaceous rock. The “ribbon rock” is highly deformed. Tightly compressed folds plunge steeply, some are nearly vertical, and a few are inverted. Thus, most beds are steeply inclined or vertical, and some are overturned. Steep to vertical slaty cleavage is common, especially south of Mars Hill, where a steep lineation results from the intersection of bedding and cleavage. Graptolites that for the first time permit reliable age determination of the “ribbon rock” were found in 1960 at a roadside exposure 2 miles east of Colby (locality 3 of fig. 30.1) by W. H. Forbes, amateur paleontologist of Washburn, Maine, who has made several other valuable fossil discoveries in this area (Berry, 1960a). The fossils occur through several feet of calcareous siltstone. They are, on the whole, poorly preserved, most having been stretched or compressed. Many, however, are preserved in re- lief, and some that are preserved as molds yielded latex peels that afford good material for study. W. B. N. Berry examined the collection and identi- fied the following forms: Amplexograptus Osp. Amplexograptus cf. A. perexcavatus (Lapworth) Climacograptus cf. C. typicalis mut. poste’ms Ruedemann Diplograptus? spp. (two distinct kinds of this form are represented; one is long and slender, the other shorter and wider) Orthograptus afi'. 0. truncatus (Lapworth) Orthograptus truncatus cf. var. intermedius (Elles and Wood) Other orthograptids of the O. truncatus type Some of the orthograptids of the 0. truncatus type are probably new. Their poor preservation, how- B—66 47°00’ __.l.— \/ A“ V N l \ Caribou 114 .I 7/ I, ashburn [15x \, State Road JMapleton ,i‘ Hal 1‘ ‘/ . Q\ \ a; ‘/ Number Nine Mtn Hodgdon x—Q 4| lO 0 Illllllllll 10 MILES FIGURE 30.1.—Known distribution of “ribbon rock” (Or) in Aroostook County, Maine. Northern part modified from White, 1943, plate 24; southern half from geologic map- ping by Louis Pavlides. Numbers refer to fossil localities. Igneous rocks within “ribbon rock” belt not shown. GEOLOGICAL SURVEY RESEARCH 1961 ever, and that of the questionable Diplograptus, pro- hibits more certain identification. The assemblage of many orthograptids of the truncatus group (especially the presence of 0. trun— catus cf. var. intermedius) , other large diplograptids, and the Climacogmptus of the C. typicalz’s group, is probably representative of the zone of Ortho- graptus truncatus var. intermedius. Closely similar assemblages have been recognized by Berry ( 1960b, p. 38) from the Snake Hill and Canajoharie shales in New York, and the Magog shale in Quebec. Berry (1960b, p. 38—39) discussed correlation of the zone with the standard New York Ordovician stages, and concluded that it was equivalent to the Trenton. Other fossils that have been found in the “ribbon rock” include elongate aggregates of ovoid pellets that were found about 1% miles southeast of Bridge- water (locality 1 of fig. 30.1). These aggregates are about 5 cm long, and 1 cm in cross section. The individual pellets are closely packed and arranged parallel to the borders of the aggregates. They are 2 to 3 mm long and slightly more than 1/2 mm in diameter. Dr. Walter Hantzschel of the Geologisches Staatsinstitut, Hamburg, examined these pellets in 1958 and he suggested they were the work of mud- ingesting worms, perhaps worms that had been given the generic name Tomaculum by Groom (1902). Such pellets were originally found in Ordo- vician rocks in England, and they have also been found in Ordovician rocks of France, Germany, and Czechoslovakia (Pénau, 1941). It is noteworthy that Dr. Hantzschel’s identification preceded Forbes’ dis- covery of the graptolites, and came at a time when many still considered these rocks to be of Silurian age. Minute fossils, none larger than 3 mm and mostly fragmentary, have been found in thin sandstone layers about 5 miles southwest of Bridgewater (lo— cality 2 of fig. 30.1)._ The fossils include smooth ostracodes, fragments of bryozoan zoaria, and brachiopods, but the material is inadequate for spe- cific identification. Brachiopods, represented by an orthoid, a rhynchonellid, and a leptellid, do not con- tradict the age assignment indicated by the grapto- lites. Rocks like those of “ribbon rock” are present to the east in New Brunswick, and the northeast along highways between Grand Falls, N. B., and Mata- pedia, Quebec, at the southwestern end of the Gaspé Peninsula. They extend, also, from Matapedia (Crickmay, 1932; Béland, 1958, 1960) across the Gaspé Peninsula to Percé (McGerrigle, 1953), the type locality of the Upper Ordovician Whitehead for- SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 mation. Although the Whitehead has an unusual shelly fauna (Schuchert and Cooper, 1930; Cooper and Kindle, 1936), its lithologic similarity to the “ribbon rock” suggests that within this belt rocks of this kind span a considerable segment of Ordovician time. REFERENCES Béland, Jacques, 1958, Preliminary report on the Oak Bay area: Quebec Dept. Mines Prelim. Rept. 375, 12 p. , 1960, Preliminary report on Rimouski; Matapedia area: Quebec Dept. Mines Prelim. Rept. 430, 18 p. Berry, W. B. N., 1960a, Early Ludlow graptolites from the Ashland area, Maine: Jour. Paleontology, v. 34, p. 1158— 1163. , 1960b, Graptolite faunas of the Marathon region, West Texas: Texas Bur. Econ. Geology Pub. 6005, 179 p. Boucot, A. J ., Griscom, Andrew, Allingham, J. W., and Demp- sey, W. J ., 1960, Geologic and aeromagnetic map of north- ern Maine: U.S. Geol. Survey open-file report. Cooper, G. A., and Kindle, C. H., 1936, New brachiopods and trilobites from the Upper Ordovician of Percé, Quebec: Jour. Paleontology, v. 10, p. 348—372. B—67 Crickmay, G. W., 1932, Evidence of Taconic orogeny in Mata- pedia Valley, Quebec: Am. Jour, Sci., ser. 5, v. 24, p. 368—— 386. Groom, Theodore, 1902, The sequence of the Cambrian and associated beds of the Malvern Hills: Geol. Soc. London Quart. Jour., v. 58, p. 89—135. McGerrigle, H. W., 1953, Geological map of Gaspé Peninsula: Quebec Dept. of Mines. Pavlides, Louis, in press, Geology and manganese deposits of the Maple and Hovey Mountains area, Aroostook County, Maine: U.S. Geol. Survey Prof. Paper 362. Pénau, Joseph, 1941, Die Anwesenheit von Tomaculum prob- lematicum im Ordovicium West-Frankreichs: Sencken— bergiana, v. 23, p. 127—132. Ruedemann, Rudolf, 1936, Ordovician graptolites from Quebec and Tennessee: Jour. Paleontology, v. 10, p. 385—387. Schuchert, Charles, and Cooper, G. A., 1930, Upper Ordovician and Lower Devonian stratigraphy and paleontology of Percé, Quebec: Am. Jour. Sci., ser. 5, v. 20, p. 161—176, 265—392. Twenhofel, W. H., 1941, The Silurian of Aroostook County, northern Maine: Jour. Paleontology, v. 15, p. 166—174. White, W. S., 1943, Occurrence of manganese in eastern Aroostook County, Maine: U.S. Geol. Survey Bull. 940-E, p. 125—161. 5% 31. RATIO OF THORIUM TO URANIUM IN SOME PLUTONIC ROCKS OF THE WHITE MOUNTAIN PLUTONIC- VOLCANIC SERIES, NEW HAMPSHIRE By ARTHUR P. BUTLER, JR., Denver, Colo. Work done in cooperation with the U.S. Atomic Energy Commission Plutonic rocks of the White Mountain plutonic- volcanic series, in New Hampshire, are slightly al- kalic and somewhat more radioactive than calc- alkalic rocks of other igneous suites in New Hamp- shire (Billings and Keevil, 1946). Some additional study of the distribution of uranium and thorium in, rocks of this series is being carried on as one aspect of the Geological Survey’s investigation of uranium and thorium in selected suites of igneous rocks. Preliminary summary of analyses for uranium has shown that felsic rocks of this series are 2 to 3 times as rich in uranium as their counterparts. among calc-alkalic rocks (Larsen and others, 1956, p. 70— 72). Thorium analyses were not available when the summary of uranium analyses was reported. The amounts of thorium and uranium and the thorium- uranium ratios in 24 samples of these rocks are summarized here.1 Work toward the results reported here began in part under the leadership of the late E. S. Larsen, Jr., and has benefited materially from consulation with E. S. Larsen, 3d, and David Gottfried on many problems. The plutonic rocks of the series range in com- position from gabbro to granite. As shown by analyses (Chapman and Williams, 1935, table 1), most of the rocks (but particularly the felsic rocks) are slightly richer in sodium and potassium and poorer in calcium than corresponding types of calc- alkalic rocks. The bulk of the rocks cropping out 1Lyons (Art. 32) presents somewhat similar data for rocks of three older plutonic series in New Hampshire. B—68 are granite, quartz syenite, and syenite (Billings and Keevil, 1946, table 1). Biotite granite occupies about 55 percent of the area of outcrop of the series. The plutonic rocks are intruded in many separate masses, some simple and some composite. The main mass, also called the White Mountain batholith (Bil- lings, 1956, p. 70), is a composite group of intrusions. It is about 33 miles long east-to-west and about 25 miles wide. Granites of this mass were sampled fairly systematically in order to obtain nearly rep- resentative data for the largest mass of rock. , Con- sequently, the data reported here are probably more nearly representative of the bulk of the granite in the batholith than are the data for other types of rock and for granites from other locations. Samples analyzed for thorium were _chosen from a much larger number of samples analyzed for uranium (Larsen and others, 1956, p. 72; Butler, 1956). The samples so chosen represent the range of uranium contents and of the rock types sampled. They include samples of gabbro, biotite-quartz mon- zonite, biotite and pyroxene—amphibole syenites, fayalite-amphibole quartz syenite, amphibole gran- ite, and biotite granite (Conway). Analyses for uranium and thorium were made in the Washington laboratory of the Geological Survey by the methods described by Grimaldi and others (1952) and Levine and Grimaldi (1958), respec- tively. A summary of the results of those analyses and 0f the thorium—uranium ratios is given in table 1. The average uranium and thorium contents in biotite granite and some amphibole granite of the White Mountain plutonic series are somewhat greater than the average contents of these elements in granites of the Oliverian and New Hampshire GEOLOGICAL SURVEY RESEARCH 1961 plutonic series, two of the older calc-alkalic plutonic series in New Hampshire (tables 2 and 4, Art. 32, this volume). However, the average values of the thorium-uranium ratio in biotite granite and amphi- bole granite of the White Mountain series is 3.8 to 4.3, which falls within the range of the ratios 3.3 to 4.3 reported by Lyons (Art. 32, this volume) in the two nearby older granites, and within the range 3.7 to 4.7 reported by Larsen and Gottfried (1960) in granites and quartz monzonites from three West— ern batholiths. In other rocks of the White Moun- tain plutonic-volcanic series, rather scattered data suggest somewhat larger values for the thorium- uranium ratio in amphibole granite of outlying masses and in some syenites than in biotite granite and amphibole granite of the main mass. Among the granite masses of the White Mountain plutonic-volcanic series the rocks of the main batho- lithic mass are slightly richer in both uranium and thorium than their counterparts in the outlying masses. Also among the felsic rocks those with lesser uranium contents tend to have higher Th/U ratios than the rocks richer in uranium. This relation, decrease in Th/ U ratio with increase of uranium, is even more distinct if the samples of felsic rocks are ‘grouped by intervals of uranium content without regard to petrographic type or geographic position as shown on page B—69. The biotite granite (Conway granite) is the only rock type for which there are enough samples to make a similar comparison among samples of one rock type. In 5 samples of this granite containing 10 ppm or more uranium the value of the Th/ U ratio is 3.1 whereas in 5 samples containing less than 10 ppm uranium it is 5.6. No petrographic features of TABLE 1.—Thorium and uranium contents and Th/U ratios in some igneous rocks of the White Mountain platonic-volcanic series, New Hampshire [Analysts, A. B. Caemmerer, E. Y. Campbell, L. B. Jenkins, and Roosevelt Moore] Uranium Thorium Number (parts per million) (parts per million) Th/U Rock type and general location of __ samples ‘ Range Average Range Average Range Average l Gabhro, Belknap Mountains ................... 1 .............. 0.9 .............. 1.0 Biotite quartz monzonite, Merrymeeting stock. . . 1 .............. 3.5 .............. 5.3 Pyroxene syenite, Pilot range .................. l ............... 1.2 .............. 8.5 Pyroxene syenite, main mass ................... 1 .............. 2.5 .............. 4.5 Amphibole-biotite syenite, Belknap Mountains. . . 2 6.9 - 8.0 7.5 25 0 — 33.5 3.9 Quartz syenite, north side Pilot Range mass ..... 1 .............. 4 . 1 .............. 6.6 Amphibole granite, Pilot range mass ............ 2 2.4 - 3.5 2.9 14.0 — 21.0 5.9 Amphibole granite (Mount Osceola type), main mass ................................. 3 3.6 — 9.9 7.4 25.0 — 40.5 4.3 Biotite granite, smaller masses ................. 3 4.3 - 14.2 9.7 30.0 — 44.0 3.8 Biotite granite, main mass ..................... 9 5.2 25.5 13.0 33.0 — 77.0 3.8 1 The average Th/U ratio is the ratio of the means of the Th and U contents. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 Uranium Number Uranium Thorium (range, in of (average, in (average, in Th/U parts per million) ' samples parts per million) parts per million) 10—255 ....... 7 15.9 51.6 3 3 5—10 .......... 8 7 6 36 . 0 4 7 1.2—5.0 ....... 8 3 2 19.4 6 3 the samples have been observed which might explain the differences in uranium contents from sample to sample or the difference in Th/ U ratios between the group of samples richer in uranium and that leaner in uranium. At present, an explanation for this difference is lacking. REFERENCES Billings, M. F., 1956, The geology of New Hampshire, Pt. II, Bedrock geology: New Hampshire State Planning and Devel. Comm., Concord. Billings, M. P., and Keevil, N. B., 1946, Petrography and radioactivity of four Paleozoic magma series in New Hampshire: Geol. Soc. America Bull., v. 57, no. 9, p. 797—828. B—69 Butler, A. P., Jr., 1956, White Mountain plutonic series, New Hampshire, in Geologic investigations of radioactive de- posits—Semiannual progress report for June 1 to Nov. 30, 1956: U.S. Geol. Survey TEI—640, issued by U.S. Atomic Energy Comm. Tech. Inf. Serv. Ext. Oak Ridge, Tenn. Chapman, R. W., and Williams, C. R., 1935, Evolution of the White Mountain magma series: Am. Mineralogist, v. 20, no. 7, p. 502—530. Grimaldi, F. S., May, Irving, and Fletcher, M. H., 1952, U.S. Geological Survey fluorimetric methods of uranium an- alysis: U.S. Geol. Survey Circ. 199, 20 p. Larsen, E. S., J r., Phair, George, Gottfried, David, and Smith, W. L., 1956, Uranium in magmatic differentiation, in Contributions to the geology of uranium and thorium by the United States Geological Survey and Atomic Energy Commission of the United Nations International Confer- ence on Peaceful Uses of Atomic Energy, Geneva, Swit- zerland, 1955: U.S. Geol. Survey Prof. Paper 300, p. 65—74. Larsen, E. 8., 3d, and Gottfried, David, 1960, Uranium and thorium in selected suites of igneous rocks: Am. Jour. Sci., Bradley volume, v. 258—A, p. 151—169. Levine, Harry, and Grimaldi, F. S., 1958, Determination of thorium in the parts per million range in rocks: Geochim. et Cosmochim. Acta, v. 14, p. 93—97. ’X 32. URANIUM AND THORIUM IN THE OLDER PLUTONIC ROCKS OF NEW HAMPSHIRE By JOHN B. LYONS, Hanover, N. H. Work done in cooperation with the U.S. Atomic Energy Commission Field studies in New Hampshire (Billings, 1937) have established the existence of four Paleozoic plu- tonic series, one of Taconic age (the Highlandcroft series), two of Acadian age (the Oliverian and New Hampshire series), and one of post-Devonian age (the White Mountain series). Chemical and spectro- chemical data relating to the distribution of uranium and thorium in the three older series are summarized in this report 1. The analytical work was done in the Geological Survey laboratories by Marian Schnepfe, Alice Caemmerer, Roosevelt Moore, E. Y. Campbell, and L. B. Jenkins. 1A paper by Butler (Art. 31, this volume) presents somewhat similar data for rocks of the younger White Mountain plutonic-volcanic series. HIGHLANDCROFT PLUTONIC SERIES All intrusives of this series have been metamor- phosed to the greenschist facies. The rocks orig- inally were quartz diorites, granodiorites, or quartz monzonites, and consist now of varying amounts of albite, microcline, epidote, quartz, chlorite, horn- blende, sphene, zircon, apatite, and opaque minerals. Uranium and thorium analyses for some rocks of this series are listed on table 1. Sphene (586 ppm), zircon (342 ppm), apatite (30 ppm), and epidote (5 ppm) are the most uraniferous minerals. The Sphene and epidote account for ap- proximately 42 percent of all the uranium in the rock. B—70 TABLE 1.—Chemical analyses for uranium and thorium in rocks of the Highlandcroft platonic series Number Uranium (ppm) Number Thorium (ppm) of of Mean Rock type samples samples Th: U analyzed Mean Range analyzed Mean Range ratio Quartz monzonite... 6 3.7 2.7—5.0 3 12.6 10.6—14.8 3.4 Granodiorite ....... 1 3.0 ........... 1 11.8 ........... 3.9 Sodaclase-tonalite. . . l 3 ,1 ........... 1 11.3 ........... 3 . 6 OLIVERIAN PLUTONIC SERIES Domal plutons of the Oliverian series consist of the following petrographic types (Billings and Keevil, 1946, p. 816): quartz diorite, 10 percent; granodiorite, 30 percent; quartz monzonite, 30 per— cent; granite, 17 percent; and. syenite, 13 percent. These rocks are at grade with the surrounding epi- dote amphibolite and amphibolite facies rocks, and consist of varying quantities of quartz, microcline, oligoclase-andesine, hornblende, biotite, epidote, muscovite, apatite, sphene, and opaque minerals. Uranium and thorium analytical data for rocks in the Oliverian series are presented on table 2. Uranium contents of minerals concentrated from 5 samples of the Oliverian series are shown on table 3. There is a consistent relation between the uranium content of each mineral and the kind of rock from which the mineral was extracted; the more felsic the rock, the higher the uranium content of each of its minerals. Approximately 70 percent (59 percent to 78 per- cent) of the total uranium in any rock of the Oli- verian series is tied up in sphene and epidote—both of which are of metamorphic origin. NEW HAMPSHIRE PLUTONIC SERIES Stocks and sheetlike plutons of this series consist of the following rock types (Billings and Keevil, 1946, p. 812) : diorite, 1 percent; amphibolite, 1 per- cent; quartz diorite to granodiorite, 23 percent; Bethlehem gneiss (granodiorite to quartz monzo- nite), 14 percent; Kinsman quartz monzonite, 26 TABLE 2.—Chemical analyses for uranium and thorium in rocks of the Oliverian platonic series Number Uranium (ppm) Number Thorium (ppm) of of _ Mean Rock type samples samples Th: U analyzed Mean Range analyzed Mean Range ratio Granite ....... 13 5.8 1.8—13.0 10 19.3 75—32 3.3 Quartz .monzomte. . 8 3.1 1.1—5.3 5 12.1 62—21 3.9 Granodiorite ....... 15 2.5 0.8—5.0 5 14.6 65—38 5.8 Quartz diorite ...... 15 1.9 0.8—3.6 6 7.1 2.9—14.8 3.7 Pegplatlte ......... 3 9.1 1.3—13.7 2 4.2 3.6—4.7 0.4”; Aplite ............. 3 9.3 2.1—15.9 3 39.2 5.5«57 4.2 Wallrocks and inclusions ....... 6 1. 3 0 . 6—1 . 8 .................................. GEOLOGICAL SURVEY RESEARCH 1961 TABLE 3.——Uranium contents of minerals of the Oliverian platonic series, [In parts per million] Number of Mineral determinations Range Mean Quartz .............. 5 0.25— 1.45 0.77 Potassium feldspar.. . . 5 .25— 1.45 .72 Plagioclase .......... 5 .25— 2.3 .97 Hornblende .......... 1 .84 .84 Biotite and chlorite. . . 4 LII—24.6 9.9 Epidote ............. 4 11.7 —204 ~ 85. Sphene .............. 5 220—411 308. Apatite ............. 4 11.1 —26.3 19.1 Zircon .............. 5 466—2770 1317 . percent; and Concord (and other) granite, 29 per- cent. These rocks are surrounded by amphibolite- and granulite-facies metamorphic rocks, with which they are at grade. Minerals include quartz, micro- cline, oligoclase-andesine, biotite, muscovite, garnet, hornblende, monazite, xenotime, allanite, zircon, and opaque minerals. Uranium and thorium contents of the major rock types of this series are listed on table 4. Minerals have been separated from 4 samples of the New Hampshire series and analyzed for uranium (table 5). Abnormally high uranium concentrations recorded for some of the minerals in these samples are the result of the inclusion of a pegmatite sample; its minerals cause the abnormality. Rocks of the New Hampshire series have between 50 percent and 90 percent of their total uranium distributed among the major rock-forming silicates. CONCLUSIONS At least three deductions or conclusions can be drawn from the analyses: (a) Uranium and thorium TABLE 4.—Chemical analyses for uranium and thorium in rocks of the New Hampshire platonic series Number Uranium (ppm) Number Thorium (Wm) of of Mean Rock type samples samples Th2'U analyzed Mean Range analyzed Mean Range ratio Granite ........... 7 4.3 2.8~5.8 5 18.3 10.7—28.5 4.3 Quartz monzonite (chiefly Kinsman) 15 3.3 l.5—6.3 6 15.7 9.1—19.-1 4.8 Quartz monzonite to granodiorite (Bethlehem gneiss) .......... 28 3.6 2.2«52 10 14.9 11.7-18.6 4.1 Quartz diorite ...... 2 3.1 2.9—3.4 1 12.2 ........... 3.9 Pegmatite ......... 3 16.7 4.7—39 3 3.9 2 8—5.0 023 Aplite ............. 3 7.2 3.3—1-1.2 2 28.6 4.3-52 4.0 Wallrocks and inclusions. ...... 5 3.3 0.8—5.0 1 16.0 ........... 4.9 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 TABLE 5.—Uranium contents of minerals of the New Hamp- shire plutonic series [In parts per million] Number of Mineral determinations Range Mean Quartz .............. 4 0.10— 2.5 0.92 Potassium feldspar.. . . 4 . 10— 1.8 .67 Plagioclase .......... 4 .30— 6.6 2.34 Biotite .............. 3 .53— 2.6 1.71 Muscovite ........... 4 1.4 — 3.1 2.20 Garnet .............. 2 0.88— 5.5 3.14 Magnetite ........... 4 2.0 —39.5 23.2 Ilmenite ............. 3 2 0 —32.7 17.0 Pyrite ............... 2 16 7 —373 195. Apatite ............. 4 1 3 —16.4 13 8 Monazite. . . . . . . . . . .: 3 624—2570 1516 Xenotime ........... 1 798 798 Zircon .............. 3 500—20 , 000 6700 analyses confirm the earlier work of Billings and Keevil (1946), based on alpha counts, both as to the B—71 general level of radioactivity, and the increase in radioactivity in the more felsic rocks of these series; (b) the thorium:uranium ratios for these rocks lie within expectable ranges for calc-alkaline plutons. Much lower ratios for pegmatites compared to aplites (table 4) indicate that the two rock types belong to different fractions of thegparent magma; (c) neo- crystallization during metamorphism apparently causes a redistribution of uranium and thorium. 'Sphene and epidote formed during recrystallization serve as traps for radioactive elements. REFERENCES Billings, M. P., 1937, Regional metamorphism of the Littleton- Moosilauke area, New Hampshire: Geol. Soc. America Bull., v. 48, p. 463—566. Billings, M. P., and Keevil, N. B., 1946, Radioactivity of four Paleozoic magma series in New Hampshire: Geol. Soc. America Bull., v. 57, p. 797—828. ’5? 33. DISTANCE BETWEEN BASINS VERSUS CORRELATION COEFFICIENT FOR ANNUAL PEAK DISCHARGE OF STREAMS IN NEW ENGLAND By JACOB DAVIDIAN and M. A. BENSON, Iowa City, Iowa, and Washington, D. C. One interesting sidelight of a recent investigation of flood-frequency relations in New England was a study of the coefficient of correlation between annual peak discharges for different pairs of streams in that area. Floods at many of the gaging stations in the area result from a few major storms that are widespread and affect many streams at the same time, rather than from scattered storms of small area] extent. It was of interest to determine a median coefficient of correlation of annual peak dis- charges between gaging stations in New England in order to determine the interdependence of the peak-flood data. To avoid the prohibitive amount of work of com- puting the 13,366 possible individual correlations between the 164 gaging stations used in the investi- gation, an estimate was made by correlating data for pairs of stations selected at random. The 164 stations were numbered consecutively from 1 to 164. Then, a table of random numbers was used from which groups of three digits were selected. The first 400 numbers of magnitude less than 165 were listed; adjacent numbers were paired. Thus, 200 pairs of numbers of magnitudes 1 to 164, represent- ing the stations with those numbers, were available and their selection was shown by a statistical test (chi-square) to be truly random. .The airline distance between the geographic cen- ters of the drainage basins of each pair of stations was then measured. The distribution of these dis- tances for the 200 pairs of stations indicated that the median distance was about 94 miles, with a range from 8 to 403 miles. The range of distances from 8 to 403 miles was subdivided into increments of about 20 miles, and a random sampling of the pairs of stations in each increment was made to cut down further the amount of work of computing correlations between stations. Within the group of stations 75 to 110 miles apart, all of the available pairs in the list of 200 were tested to obtain a better value of the correlation coefficient for the median distance of 94 miles. A total of 54 B—7 2 1.0 0.95 confidence limit, basins 75 to 110 miles apart .1 ' 0.8 .0 as .0 as I COEFFICIENT OF CORRELATION Q o 70.2 .104 I l I l I 10 2O 50 100 DISTANCE, IN MILES FIGURE 33.1.—Relation between correlation coefficient of annual peak discharges and distances between basins. pairs was used. The annual peak discharges for the selected pairs were listed for concurrent periods and were ranked in order of magnitude. For each pair, the Spearman rank coefficient of correlation was de- termined. Of the 54 pairs, 8 had negative correla- tion coefficients. In figure 33.1 the coefl‘icient of correlation between stations (arithmetic scale) is plotted against dis- tance between stations (logarithmic scale). A coef- ficient of correlation of about 0.26 corresponds to the median distance of 94 miles, and is taken to be the median correlation coefficient for the 164 New England stations that were considered in the original study. The curve has been drawn so that the ex- tremes would be asymptotic to 1.0 and 0.0. The curve shows an increasingly good correlation with de- creasing distance separating the basins. ' The 27 pairs of stations between 75 and 110 miles apart were studied more thoroughly to test the sig- nificance of the scatter within the band. These 27 pairs have an average of 17.3 years of concurrent records. The 95-percent confidence belt for the sample correlation coefficient of 0.26 and the sample size of 17.3 ranges between —0.25 and +0.64. This means that although a median value of 0.26 is indi- cated on the illustration, pure chance alone leads to a scatter between —0.25 and +0.64 for 95 percent of the observations. These limits are somewhat ap» proximate because the periods of record have been GEOLOGICAL SURVEY RESEARCH 1961 I averaged. For these 95-percent confidence limits, I 1.35 points would be expected outside the limits; actually there are 4 points, which is a significant difference statistically and which suggests the pos- sibility of unknown factors causing more scatter than could be expected by chance alone. Negative coefficients of correlation are to be expected by chance for stations having relatively short concur- rent records. Had the average length of concurrent record between pairs of stations been about 45 years instead of 17.3 years, the 95-percent confidence limits for a median correlation coefficient of 0.30 would have been 0.0 to +0.55. It is generally considered that stations with like characteristics will have a higher degree of correla- tion than stations with unlike characteristics. There- fore, an attempt was made to relate the departures of correlation coefficient from the median curve of the graph shown with (a) difference in drainage area size, (b) ratios of drainage area size, (c) num- ber of years of concurrent record, (d) difference in an “orographic factor” evaluated in the New Eng- land flood—frequency study, and (e) difference in average winter temperatures (a measure of the dif- ference in the types of flood peaks). None of these seemed to relate to the departures in the degree of correlation. It might be expected that a correlation between two small drainage areas, for example 100 miles apart, would be less than the correlation between two large areas the same distance apart. Any such differences cannot be detected in this set of data, possibly because the differences are much smaller than the variations due to chance. Apart from dis- tance between stations, present hydrologic knowl- edge cannot aid us in predicting which pairs of sta- tions would correlate well or which would correlate poorly. Even though two drainage basins were sep- arated by a high mountain barrier transverse to the storm winds, the annual peak discharges for each, though far different in magnitude, might be pro- portional. ‘ This study indicates that a high coefficient of correlation between the annual peak discharges of two streams picked at random may be due to chance. In estimating peak discharge for years of no record, a station that appears to correlate best may not give better results than one of the other stations. Addi- tional research on the use of correlative estimates of flood peaks is needed. ’X‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 34. B—7‘3 PLEISTOCENE STRATIGRAPHY 0F BOSTON, MASSACHUSETTS By C. A. KAYE, Boston, Mass. An excavation in 1960 for a large underground garage in the lower slopes of Beacon Hill, at the western edge of the Boston Common, proved to be a key exposure for the unraveling of the Pleistocene stratigraphy of the area. Evidence for 4—and prob- ably 5—ice advances and 3 marine transgressions occur in, or under, the garage and the surrounding lowland. Study of many hundreds of deep borings in the Boston basin, and soil-mechanics test data on compaction of materials, support these conclusions. Pregla-cial surface.——Bedrock beneath the garage (fig. 34.1) consists of argillite of the Cambridge slate. The argillite is altered to a soft white kaolinitic saprolite under the southeastern part of the site, where it is buried by about 85 feet of Pleistocene deposits. Similar saprolite has been found in deep borings in at least six other places in the Boston basin. In one of the garage borings, weathered ar- gillite was found to be overlain by 10 feet of fairly coarse quartz sand in a white clay matrix. This re- sembles kaolinitic quartz sands of Late Cretaceous age (Raritan(?) formation) on Martha’s Vineyard, Block Island, Long Island, and New Jersey. Patchy remnants of Coastal Plain sediments may therefore occur in the Boston basin. Drift I.—In 9 borings at the garage site, as much as 30 feet of very compact till was found at the base of the Pleistocene section (fig. 34.1). It is prevail- ingly a pebble till, poor in cobbles and boulders, and somewhat variegated in color. The high degree of compaction of the till is shown by standard penetra— tion tests (Terzaghi and Peck, 1948, p. 265) which average more than 100 blows per foot. This thin dense till has been found in many deep borings in the Boston basin but has not been recognized on the surface. , Clay I. ——As much as 25 feet of fairly soft to com- pact olive-gray unoxidized clay, sandy clay, and very fine sand was found between Drifts I and II in five garage borings. The clay is identical in appearance to certain clays along the New England seaboard that are recognized from sparse fossils to be of ma- rine origin. Standard penetration tests ranged from 5 to 40 blows per foot. Clay I has not been recog- nized in surface exposures, and borings in the Boston area indicate that it has been preserved in only a few places. Drift II.—This consists mostly of thick outwash, but some underlying till is associated with it in several of the garage borings (fig. 34.1). Outwash Borings on, or referred to, this cross section ’0utline‘oi excavation i Drift ill i- SEA LEVEL- 20’- Clay II 40'- Drift II 60'- Cambridge slate 50 Common garage excavation and line of section AQQ;W/ ’ 7 ‘ i Y SOUTH - 30' 18th century shoreline\ Outline of excavatiom ii - 20' >SEA LEVEL ~ 60’ — 80' -100’ 100 FEET .MvOOOO. ,..Saprolite.. 0o .o.9.:.:. ’ 0‘0 ~120' FIGURE 34.1.——-North-south geologic cross section, lower Boston Common, at site of underground garage. B—7 4 of Drift II was well exposed in the garage excava- tion and crops out at the surface quite widely in the Boston area. It is characteristically a brown, well- oxidized coarse gravel interbedded with somewhat lesser amounts of fine gravel and sand and relatively sparse layers of compact yellow silt. Outwash under the garage is about 65 feet in maximum thickness and it is oxidized throughout. Sparse samples and drillers’ logs are inconclusive as to whether the underlying associated til] is oxidized. Pebbles of schist and argillite in the outwash show varying de- grees of decomposition, but, in general, most granitic rocks and feldspars appear fresh. At the garage the gravel has been folded into a series of three anticlines (fig. 34.1), presumably by the action of the ice that deposited Drift III. Clay II .-—Another clay having the physical charac- teristics of marine clays overlies Drift II at the garage excavation (fig. 34.1). It is unoxidized (blue gray to slightly greenish gray) except where close to the present surface. Clay II was deformed with Drift II. This is evident from numerous small faults in the gravel, formed during the folding, which ex- tend up into the clay. Stratification of the clay— FIGURE 34.2.—Contact of Drift III (above) and Clay II (be- low), showing scant signs of disturbance. East wall of excavation, underground garage, Boston Common. GEOLOGICAL SURVEY RESEARCH 1961 marked by alternating lighter and darker laminae— is well marked in some zones. The contact of the clay and the overlying till is generally quite sharp; in places the bedding of the clay shows no disturb- ance whatever at the contact (fig. 34.2), in others gross bedding disturbances in the clay'are evident to a depth of 3 or 4 feet below the contact. In several places in the excavation the contact is deformed into fairly large waves (fig. 34.1). Drift III.—At the garage excavation more than 30 feet of till overlies Clay II. It appears to be the major component of Beacon Hill drumlin and prob- ably the other drumlins of the Boston area. It is very well graded but has sparse boulders up to 10 feet in diameter. Cobbles and stones are predomi- nantly of Cambridge slate and are generally con- spicuously striated. A fabric study of the pebbles shows a preferred orientation of axial planes parallel to the long axis of Beacon Hill and adjacent drumlins (approximately S. 70° E.). The maximum depth of oxidation seen in the till at the garage excavation was 25 feet, although deep borings in Beacon Hill show the till there to be oxidized to a maximum depth of 65 feet. Differences in depth of oxidation are probably due mainly to differential erosion of the oxidized zone by the ice responsible for Drift IV. Fragments of shells—mostly very thick shelled M ercenam'a mercenariar—occur in the till of Beacon Hill and other drumlins. These are possibly derived from Clay II. Clay III .—This clay forms the bulk of the marine clay in the Boston basin and attains a thickness of 180 feet in a few places. In physical appearance it resembles the two older clays. It crops out as a patch over Drift III in the northeast corner of the garage excavation at about 15 to 25 feet altitude. Many borings in the Boston area show that it over- lies drumlin till (Drift III) ; therefore, there can be no doubt that it is separate from, and younger than, Clay II. Borings indicate that where overlain by Drift IV, Clay III is oxidized to a depth of about 3 feet. Where exposed at the surface it is oxidized to a maximum depth of 10 feet. Marine mollusks were found in Clay III by the writer at West Lynn, at the north edge of the Boston basin, and Foramini- fera were reported by Stetson and Parker (1942, p. 42) from the clay in Boston Back Bay. Sparse em- bedded cobbles and small stones suggest ice-rafting and therefore deposition at a time when an ice front may have been close to Boston. Spruce pollen is very abundant in the upper 10 feet at West Lynn (Estella B. Leopold, written communication), thus supporting a cold climate—or periglacial—depositional environ- SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 TABLE 1.—Pleistocene deposits of Boston, Mass. B—7 5 Deposit Description Remarks Depth of oxidation 1 Direction of Relative sea Suggested age Standard Pleistocene ice flow level 2 in years sequence Boston basin: In outwash Lower than 13,000 Late Wisconsin mostly outwash. generally less —-30 ft. Drift IV Uplands: till and than 4 ft, in S. 10°—30° E. (Cary sub- outwash. till 1% ft. stage; Lex- ington sub- stage of Judson) 15,000 ________ Oxidation of Clay III Lower than —35 ft. 26,000 ———————— Marine clay. Possibly de- 3 ft under Found to alti- More than 180 posited when Drift IV, 10 tude +25 ft ft thick under ice front was ft elsewhere. in Boston. . Clay III lowlands. Pre- not far from Contalns fairly Middle compressed to Boston. deep water Wisconsin depths of 70 ft. fauna sug- (Tazewell gesting sea substage) level above +50 ft. — 28,000 ________ Oxidation of Drift III Lower than — 20 ft. A 65,000 ________ The drumlin till. Very compact Maximum 65 ft Possibly above ‘ . in drumlins; in drumlins; +50 ft. Early Wisconsin Drift III less compact where less, S. 60°—80° E. (Iowan as ground oxidized zone substage) moraine. probably eroded by Late Wiscon- sin ice. ~~ 75.000 ———————— Probably marine. Probably source None where Possibly about of shells in recognized. +50 ft. Drift III. May have Early Iowan (1’) Clay II May have been eroded. Sangamon been deposited interglacial during advance of Iowan ice. 77.000 (?) ———————— Oxidation of Drift II —45 ft (7) Sangamon interglacial . 100,000 ———————— .. Mostly gravelly Folded in 65 ft or more Unknown. Below —75 ft. Drift II outwash; some places. in sand and Illinoian associated till. gravel. Some pebbles decomposed. (1’) ———————— Probably marine. Recognized only None noted; —45 ft or Early Clay I in borings. possibly above. Illinoian (7) eroded. Yarmouth (‘3) , (‘3) ———————— _ Very compact til]. Recognized with None noted. Unknown. (‘3) (‘3) Drift I certainty only Kansan or in deep borings, Nebraskan 1 Oxidized zone of all units but Drift IV was subject to erosion by later ice. 2 Altitudes refer to present mean sea level. B-76 ment. Although much of the clay is very soft (standard penetration test, 2 to 3 blows per foot), soil mechanics studies (A. Casagrande, written com- munication) show that it is precompressed (Terza- ghi and Peck, 1948, p. 67) to a depth of as much as 70 feet below its surface. It is thought that this precompression resulted from the ensuing glaciation responsible for Drift IV. Drift IV.-—Overlying Clay III in many places in Cambridge and the Back Bay are outwash gravels that are only slightly oxidized and rarely exceed 20 feet in thickness. They are correlated with the poorly compacted and barely oxidized tills (oxidation gen- erally less than 2 feet) that are found with patchy distribution on the uplands surrounding the Boston basin. This drift belongs to what Judson (1949) termed the Lexington substage of the Wisconsin. It is now fairly certain that the late Wisconsin ice re- sponsible for it flowed approximately S. 20° E. and covered the entire Boston basin, probably reaching the outermost moraines off the southeastern New England shore. The direction of ice movement is in GEOLOGICAL SURVEY RESEARCH 1961 marked contrast to that of the drumlin-forming Iowan ice (table 1), which flowed approximately S. 70° E. ‘ Table 1 summarizes the more salient facts about the Pleistocene section. Relative ages were assigned to the later drifts primarily on the basis of their depths of oxidation. REFERENCES Judson, S. 8., Jr., 1949, The Pleistocene stratigraphy of Bos- ton, Massachusetts, and its relation to the Bolyston Street Fishweir, in Johnson, F., ed., The Boylston Street Fish— weir II: Phillips Acad., Robt. S. Peabody Foundation for Archaeology Papers, V. 4, no. 1, p. 7—48. Stetson, H. C., and Parker, F. L., 1942, Mechanical analysis of the sediments and the identification of the Foramini- fera from the building excavation, in Johnson, F. and others, The Boylston Street Fishweir: Phillips Acad., Robt. S. Peabody Foundation for Archaeology Papers, v. 2, p. 41—44. Terzaghi, Karl, and Peck, R. B., 1948, Soil mechanics and engineering practice: New York, John Wiley & Sons, 566 p. 6% 35. IRON ORES OF ST. LAWRENCE COUNTY, NORTHWEST ADIRONDACKS, NEW YORK By B. F. LEONARD and A. F. BUDDINGTON, Denver, Colo., and Princeton, N. J. St. Lawrence County is a major producer of mag- netite and crystalline hematite concentrates from low-grade ores of Precambrian age. The rocks of the district are mainly granitic. They are separated into an older quartz syenite gneiss Series and a younger granite and granite gneiss series. Metasedi- mentary rocks, migmatites, and other rocks are subordinate. All the rocks except some granites and basaltic dikes have in some measure been dynamo- thermally metamorphosed. The iron ore bodies are restricted to a structural knot of metasedimentary rocks and younger granitic rock, the latter representing members of the granite and granite gneiss series. Within this knot, de- veloped at the intersection of two dominant regional structural trends, the metasedimentary rocks and sheets of younger granitic rock have been pressed into variously oriented isoclinal folds against but- tresses of older granitic rock (fig. 35.1). Other major structural controls for iron—oxide mineralization have been recognized. All the major deposits are (a) on or within a mile of the borders of great areas of subperpendicular lineations, or (b) well within the central zone of subparallel lineations at places where lineations culminate, diverge, or change markedly in trend‘. All the deposits are within a mile of the axes of major synclinal folds. Moreover, all the deposits are within 500 feet of at least one facies of the younger granite and granite gneiss. The iron ores are of two types: magnetite de- posits in skarn or marble (skarn ores), and mag- 1Subparallel lineations are mineral lineations whose rake is within 30° of the strike of the foliation, and subperpendicular lineations are those whose rake is within 30° of the direction of dip of the foliation (Budding- ton, 1956). SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 ST LAWRENCE COUNTY Adirondack glen Ch \ ,—,3'“V Zak/t“ Russelly/f . :1. 7% 0| (Jr B—77 EXPLANATION \ .\ ' .‘I . \’\‘, Younger granite and granite gneiss series A fig PREcliflgRIAN +¢ +i+ Quartz syenite gneiss series Metasedimenlary rocks, migmatites, and subordinate amphibolite J / Contact 1 /. ’/ Fault, approximately located Queried where inferred 5 Anticline Showing truce ofluial plane and bearing and plunge ofuis Anticline, locally overturned Showing trace ofaxial plane, direction of dip aflimbs, and beariny and plunge (Jan's 4" _ «- ’ Syncline Showing trace qfarial plane and bearing and plunge ofaxix. ‘ ‘L .3— —— Syncline, locally overturned and bearing and plunge ufaxix W Plunge of fold axes o Magnetite deposit of skarn type Geology by A F Buddington andB F Leonard 1943—49 FIGURE 35.1.—Relation of magnetite deposits to major rock units and fold axes, St. Lawrence County magnetite district, New York. netite deposits—With or without hematite—in micro- cline granite gneiss (granite gneiss ores). Magnetite, virtually nontitaniferous, is the only significant iron oxide in skarn ores. The principal gangue mineral is green clinopyroxene, though bio- tite or dark amphibole is conspicuous locally. The skarn ores are variable in grade (generally 30-44 percent magnetic Fe), complex in structure, and small to moderate in size, tending to yield massive ore bodies. One major deposit and parts of several others are in skarn that was partly replaced by quartz, untwinned barium-bearing potassium feld- spar, fluorite, barite, and scapolite before introduc- tion of the magnetite. The granite gneiss ores contain magnetite, accom- panied in some places by slightly titaniferous pri— mary crystalline hematite. This hematite, with or without martite, forms sizable ore bodies locally. The principal nonmetallic minerals are quartz, un- tWinned barium-bearing potassium feldspar, bio- tite, manganiferous almandite, and sillimanite. The granite gneiss ores form disseminated deposits of uniformly low grade (generally about 25 percent recoverable Fe), remarkable continuity, and moder— B—7 8 ate to very large size. One ore deposit is in gneiss that was partly replaced by quartz, barium-bearing potassium feldspar, fluorite, barite, and spessartite before introduction of iron oxide. The iron ore deposits are mainly concordant with the complex structure of the country rock which they replace. At very large and very small scales, the deposits are nevertheless discordant. In shape, the deposits are tabular, fishhook, linear, mimetic after multiple drag folds, and “complex.” Deposits of complex shape are controlled by sets of intersect- ing fold axes of two or more distinct generations. Most deposits of the district, though imperfectly known, seem to have two long dimensions and one short one; that is, they are sheetlike rather than lath- or rod-shaped. Many deposits have a fishhook shape, the ore having replaced the nose and part of one limb of a syncline. Though magnetite and hematite are the only ore minerals in the deposits, other metallic minerals are associated with them. Arranged roughly according to decreasing frequency and quantity, these minor associates are pyrite, pyrrhotite, chalcopyrite, sphalerite, molybdenite, bornite, ilmenite, mar- casite(?), chalcocite, covellite, vonsenite, loellingite, graphite, unidentified minerals, and valleriite(?). Vonsenite (ferrous ferric borate) is an important mineral in one deposit. A little maghemite, very likely supergene, has been found in a single deposit. The rarer metallic minerals are detectable only un- der the microscope. There seems to be no systematic distribution of sulfides according to type of mag- netite deposit, though concentrations of pyrrhotite are usually associated with skarn ores and con- centrations of pyrite with granite gneiss ores. Most of the metallic minerals associated with magnetite and hematite are related to the main mineralizing episode that yielded the iron oxides. However, some metallic minerals belong to a later stage, and a few are referred to a stage of late hydrothermal minerali- zation that yielded minerals of the epidote group, zeolites, fluorite, quartz, calcite, clay minerals, and others. The magnetite deposits and the hematite bodies locally associated with them are closely related in space, time, and origin. They are thought to be high—temperature replacement deposits effected by emanations from younger granite magma, though the ultimate source of the iron is still conjectural. The deposits represent one aspect of a process that, under slightly different and definitely cooler condi- tions, yielded pyritic sphalerite deposits, pyrite and pyrrhotite deposits, and perhaps also tremolite-talc GEOLOGICAL SURVEY RESEARCH 1961 deposits in the Grenville lowlands northwest of the massif. (Cf. Engel and Engel, 1958.) The first major deformation of the Adirondack rocks took place after the consolidation of the quartz syenitic rocks and before their intrusion by scattered dikes of hypersthene metadiabase. Subsequently, younger granite magma was intruded into the meta- sedimentary rocks and partly metamorphosed older igneous rocks. This magma, which consolidated chiefly as hornblende-microperthite granite, difl’er- entiated to give a volatile-enriched phase that worked upward and outward, crystallizing as alaskite, in part as “roof rock,” in part as satellitic sheets and phacolithic bodies in the metasedimentary rocks. Probably the same fundamental magma also yielded a high-potassium, volatile-enriched phase that in- truded the metasedimentary rocks as thin sheets, reacted with the country rock, and in places meta- somatized it extensively, yielding heterogeneous microcline granite gneiss. Locally, the younger granitic rocks were deformed. An advance wave of metasomatism by volatile emanations rich in F, OH, and Si, locally accompanied by B, Cl, and P, preceded the intrusion of some of the granite and formed skarn. Once the skarns had been developed and partly enriched in iron, and the heterogeneous micro- cline granite gneiss had formed, both rocks were locally modified by introduction of quartz, untwinned potassium feldspar, fluorite, barite, and scapolite or spessartite. Such modification, appreciable only where skarn was enclosed in microcline granite gneiss, represents a continuation or renewal of the same process that developed all the microcline granite gneisses of the district. At sites favorable because of their structure and their proximity to the supply of metasomatizing solutions, the skarns were subjected to the progres- sive introduction of more iron. Initially, iron was substituted within the silicate lattice of diopside, producing salites and ferrosalites. Where the ap- propriate concentrations of volatiles existed, py- roxenes were locally replaced by amphiboles or by micas. Local access of Fe“, or perhaps merely local oxidation of Fe”, permitted the development of an- dradite skarn. At some appropriate but unknown pressure, temperature, and degree of concentration, the silicates could no longer accommodate all the Fe within their lattices; at that stage, magnetite was precipitated, closely followed by a series of simple sulfides, minor in quantity. Very similar processes, locally affecting biotite- or sillimanite-microcline granite gneiss, resulted in the formation of mag- netite deposits in those rocks. Perhaps the local de- SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 velopment of hematite in the granite gneiss ores (representing an increased oxidation state of the Fe) is analogous to the local development of an- dradite in the skarns, where primary hematite is lacking. Progressive decrease in the concentration of Fe, decreasing temperature, and a change in the character of the metasomatizing solutions toward a dilute water-rich fluid led to local alteration and partial leaching of ore and wall rocks, followed by deposition of hydrous silicates, calcite, and sporadic base-metal sulfides. At some later date—possibly in late Precambrian time, possibly in Silurian or younger time—a few of the deposits were faulted. Still later, faults, joints, and permeable rock units conveyed surface waters downward, yielding local masses of earthy hematite and chlorite. The evidence of supergene alteration of the de- posits is generally slight, for the bedrock of the region was thoroughly scraped by Pleistocene gla- ciers. “Rotting,” leaching, limonitization, and clay- mineral alteration are apparent at the suboutcrop of some deposits deeply mantled by glacial debris. Earthy hematite and chlorite form streaks and small masses along joints, faults, mica-rich zones, and marble layers in a few deposits. This type of altera- tion is comparable to that which affected the sulfide- bearing schists of the nearby Grenville lowlands and resulted in the development of scattered bodies of supergene hematite in marble. The regional geology and ore deposits of the dis- trict are treated by Buddington and Leonard in reports now in preparation. Critical structural fea- tures are discussed by Buddington (1956), whose paper lists the major references on regional geology of the northwest Adirondacks. Representative mag- netite deposits are described by Buddington and Leonard (1945) and by Leonard (1952, 1953). Min- eralogic features of a borate-bearing skarn deposit are presented by Leonard and Vlisidis (in press). Preliminary exploration of several deposits is sum— marized by Balsley, Hawkes, and others (1946), Hawkes and Balsley (1946), Millar (1947), and Reed and Cohen (1947). Regional aeromagnetic and geo- logic data are shown on maps by Balsley, Hawkes, and others (1946), and by Balsley, Buddington, and others '(1954a, 1954b, 1959a, 1959b). Magnetic ef- fects due to Fe-Ti oxide minerals in the country rock are interpreted by Balsley and Buddington (1958), and the usefulness of these minerals as geother- mometers is demonstrated by Buddington, Fahey, and Vlisidis (1955). B-79 REFERENCES Balsley, J. R., and Buddington, A. F., 1958, Iron-titanium oxide minerals, rocks, and aeromagnetic anomalies of the Adirondack area, New York: Econ. Geology, v. 53, p. 777—805. Balsley, J. R., Buddington, A. F., and others, 1954a, Aeromag- netic survey and geologic map of the Cranberry Lake quadrangle, New York: U.S. Geol. Survey Geophys. Inv. Map GP—118. , 1954b, Total aeromagnetic intensity and geologic map of Stark, Childwold, and part of Russell quadrangles, New York: U.S. Geol. Survey Geophys. Inv. Map GP—117. , 1959a, Aeromagnetic and geologic map of the Os- wegatchie quadrangle, St. Lawrence, Herkimer, and Lewis Counties, New York: U.S. Geol. Survey Geophys. Inv. Map GP—192. , 1959b, Aeromagnetic and geologic map of the Tupper Lake quadrangle, St. Lawrence, Hamilton, and Franklin Counties, New York: U.S. Geol. Survey Geophys. Inv. Map GP—193. Balsley, J. R., Hawkes, H. E., and others, 1946, Aeromagnetic map showing total intensity 1,000 feet above the surface of part of the Oswegatchie quadrangle, St. Lawrence County, New York: U.S. Geol. Survey Geophys. Inv. Prelim. Map 1. Buddington, A. F., 1956, Correlation of rigid units, types of folds, and lineation in a Grenville belt, p. 99—119 in Thomson, J. E., ed., The Grenville problem: Royal Soc. Canada Spec. Pubs. 1, 119 p. Buddington, A. F., Fahey, Joseph, and Vlisidis, Angelina, 1955, Thermometric and petrogenetic significance of titaniferous magnetite: Am. Jour. Sci., v. 253, p. 497—532. Buddington, A. F., and Leonard, B. F., 1945, Geology and magnetite deposits of the Dead Creek area, Cranberry Lake quadrangle, New York: U.S. Geol. Survey Prelim. Rept. 106053 [mimeographed]. Engel, A. E. J., and Engel, C. G., 1958, Progressive meta- morphism and granitization of the major paragneiss, northwest Adirondack Mountains, New York. Part I. Total rock: Geol. Soc. America Bull., v. 69, p. 1369—1413. Hawkes, H. E., and Balsley, J. R., 1946., Magnetic exploration for iron ore in northern New York: U.S. Geol. Survey Strategic Minerals Inv. Prelim. Rept. 3—194 [mimeo- graphed]. Hawkes, H. E., Balsley, J. R., and others, 1946, Aeromagnetic survey at three levels over Benson Mines, St. Lawrence County, New York: U.S. Geol. Survey Geophys. Inv. Prelim Map 2. Leonard, B. F., 1952, Magnetite deposits and magnetic anomalies of the Brandy Brook and Silver Pond belts, St. Lawrence County, New York: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—6. , 1953, Magnetite deposits and magnetic anomalies of the Spruce Mountain tract, St. Lawrence County, New York: U.S. Geol. Survey Mineral Inv. Field Studies Map MF—10. Leonard, B. F., and Vlisidis, A. C. (in press), Vonsenite at the Jayville magnetite deposit, St. Lawrence County, New York: Am. Mineralogist. B—80 Millar, W. T., 1947, Investigation of magnetite deposits at Star Lake, St. Lawrence County, N. Y. (to November 1945): US. Bur. Mines Rept. Inv. 4127. GEOLOGICAL SURVEY RESEARCH 1961 Reed, D. F., and Cohen, C. J., 1947, Star Lake magnetite de- posits, St. Lawrence County, N. Y. (November 1945 to November 1946): US. Bur. Mines Rept. Inv. 4131. % 36. CHARACTERISTICS OF SEICHES ON ONEIDA LAKE, NEW YORK By JOHN SHEN, Washington, D. C. Seiches are series of oscillating standing waves caused by strong Winds or sudden changes in baro- metric pressure. Depending on the nature of such disturbing sources, seiches may be uninodal, binodal or multinodal; any number may coexist. Good ex- amples of seiches have been observed frequently at a Geological Survey recording gage at Brewerton, Oneida Lake, N. Y. A recording of the water-surface fluctuations during typical seiches is shown in figure 36.1. In general, seiche waves possess the characteristics of shallow-water waves and may thus be closely ap- proximated by sine functions. For a simple rec- tangular basin, the period of oscillation may be com- puted by T_ 2L, _' kx/g 17 (1) in which L is the length of the basin; D is the depth of the basin; 9 is the gravity acceleration; and, k is the number of nodes. Equation 1 is applicable only to a closed basin of constant depth. For irregular basins, Du Boys (1891) proposed the equation: T~§ de in which d is the depth corresponding to a length increment, dx, along the line of greatest depth through the basin. Du Boys’ equation is considered applicable to parabolic and quartic basins which approximate many natural lakes (Chrystal, 1906). After the disturbing source of a seiche ceases to exist, the oscillations continue with diminishing amplitudes. The effect of such damping may be de— scribed by a decay-type function (Keulegan, 1959, p. 34) : m A : AUQ ‘am, (3) Where, A, is the amplitude of oscillation at the initial set—up ; A is the amplitude at any one subsequent in- terval; m is the order number of the oscillations and is equal to the time elapsed from A, divided by the wave period; and, a is a constant, known as the modulus of decay, depending on the physical charac- teristics of the basin. The period of oscillation of Oneida Lake was computed by Du Boys’ equation. A longitudinal profile of the lake was obtained by plotting the mean depth along its navigation line, and this profile, shown on figure 36.2, was used to represent the section of greatest depth. Details of the computation for summation of dx/ Vd are shown on table 1. As- suming the seiches on Oneida Lake are uninodal, the period of oscillation would be: 2 X 20,630 V3272 X 60 X 60 : 2 hours, 1 minute. T: Comparing with the actual observed period of 1 hour and 57 minutes, the computed value is a close approximation. 10.0 5" o STAGE (FEET) 21 9° 0 JUNE 1954 FIGURE 36.1.-—Water-surface oscillations on Oneida Lake, during seiches of June 21 to 22, 1954. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—81 TABLE 1.—Computation of seiche period of Oneida Lake. 20 DEPTH lFEET) 40 60 0 80 DISTANCE {THOUSANDS OF FEET] FIGURE 36.2.-—Longitudinal profile of Oneida Lake. The damping characteristics of Oneida Lake were also investigated. By rearranging equation 3, we have ‘ e) The value of a may be readily determined by plotting values of (A/A.,) against values of 0434772 on semi- log graph paper. Figure 36.3 shows such a plot for the seiches which occurred on Oneida Lake during June 21 to 22, 1954. From this plot, the value of a was found to be 0.476. The foregoing example illustrates the exponential damping characteristics of a natural basin. Other natural basins having greater moduli of decay are known. For example, Lake Erie possesses a value of a : 0.86 (Hunt and Bajorunas, 1959). The nodes would not be symmetrically located for an irregular basin; however, the position of the 0.434am. 0.60 .0 a. O 9 N o VALUE OF A/Ao 0.05 0 3 2 VALUE OF 0434 m FIGURE 36.3.—Determination of a, the modulus of decay, of Oneida Lake. 1 A95 (1 l _ 1 _ 1 _ Station.:c 1 (in feet) (in feet) 1 Vol 1 Ax/ \/d ‘ 1/ ng 1 1 110,000 10,000 20 5.10 1,000 0.0345 100,000 10,000 39 6.25 1,000 .0282 90,000 10,000 41 0.40 1,560 .0275 80,000 10,000 42 6.48 1,540 .0271 70,000 . 10,000 39 6.25 1,600 .0282 00,000 10,000 34 5.82 1,720 .0303 50,000 10,000 27 5.19 1,930 .0340 40,000 10,000 21 4.58 2,180 .0384 30,000 . 10,000 20 4.47 2,240 .0395 20,000 10,000 18 4.24 2,360 .0416 10,000 0,700 12 3,46 1,940 .0509 3,300 2 100,700 20,630 Gib node or nodes may be approximately determined by plotting the value of 1/ Vg—d against the distance, x, and measuring the area under the resulting curve. A uninode will occur at a value of x that divides the area into 2 equal parts; binodes will occur at the values of x that divide the area into 4 equal parts. On this basis the position of theuninode on Oneida Lake was found to be at 48,300 feet (fig. 36.2). REFERENCES Chrystal, G., 1906, On the hydrodynamical theory of seiches: Trans. Roy. Soc. Edinburgh, v. 41, p. 599—649. Du Boys, P., June 1891, Essai théorique sur les seiches: Archives des Sciences Physiques et Naturelles, Geneve, p.628. Hunt, I. A., and Bajorunas, L., June 1959, The effect of seiches at Conneaut Harbor: Am. Soc. Civil Engineers, Proc. v. 85, WW 2, p. 31—41. Keulegan, G. 11., July 1959, Energy dissipation in standing . waves in rectangular basins: ,Jour. Fluid Mechanics, Cambridge, v. 6, p. 33—50. ‘ B—82 GEOLOGICAL SURVEY RESEARCH 1961 37. VARIATIONS OF pH WITH DEPTH IN ANTHRACITE MINE-WATER POOLS IN PENNSYLVANIA By WILBUR T. STUART and THOMAS A. SIMPSON, Arlington, Va. When mining of anthracite coal was a flourishing industry during the 1920’s and during the years of World War II, the water pumped from the mines was strongly acid and created pollution problems in the streams. When the coal was exhausted and the mines abandoned, pools of water accumulated in the underground workings. In some mines the pools drained naturally, and in others water was pumped to prevent overflow into adjacent active mine work- ings. These waters had considerable range in acid content (Felegy, Johnson, and Westfield, 1948) and their action on the pumping machinery required acid- resisting components. Knowledge of the areas or zoning of the acid waters might make control of pollution easier and reduce the cost of handling the water. During the investigation, under Public Law 162, 84th Congress, of pump projects relating to anthra- cite mine drainage, it was noted that the pH of the water in certain flooded mines varied with the depth below the surface of the pool. In some pools less acidic or fresh-water zones occurred near the sur- face above more acid waters at depth. Vertical shafts penetrating flooded mines were randomly selected in each of the four anthracite fields of Pennsylvania for determining the presence of layering of the acid water. Isolated unpumped pools, pools pumped periodically, and pools having continuous circulation by overflowing were included in the sampling. At each shaft the pool was sampled 25 feet below the pool surface and 75 to 100 feet above the bottom of the shaft. One or two samples were taken at points uniformly spaced between the upper and lower sampling levels. The sampling was done by lowering a stoppered thick-walled bottle on a measured line to the desired depth. A long and a short open capillary tube through the stopper permitted the water to enter the bottle and the air to be released. The time that the bottle was in position at the sampling site was long compared to the time required to lower and raise it to the pool surface. Large bottles were used at depths of more than 400 feet, medium sizes be- tween 100 and 400 feet, and small sizes for near— surface samples. The pH of the samples was determined imme- diately at the shaft collars by a Beckman Model N pH meter. The pH was determined to the nearest 0.01 unit, but in reporting the results in table 1, the determination is rounded to the nearest 0.05 unit. Table 1 shows the range in pH in eleven mine- water pools in the four anthracite fields. The pools at the South Wilkes-Barre and Henry mines are relatively new pools isolated from other mines and have not been pumped. The pH in these pools indi- cate more acid water at depth. The Greenwood mine contains an isolated new pool and the level of the pool is rising at present. The pH in this pool indi- cates more acid water in the lower sections. The pool in the Clearspring mine is about 15 years old and has not been pumped. It reportedly receives re- charge from and discharges to the buried valley of the Susquehanna River. The range in pH in this pool does not indicate any significant layering of acid water. The mine-water pools in the Exeter, Schooley, N0. 7, Reliance, and Packer mines are not appreciably layered. The pools have been pumped at intervals either to prevent overflow or to obtain water for processing of prepared coal. Water enters pools at each of these mines at several levels corresponding to the points where the mine shafts intersect water- bearing coal beds. This tends to keep the pool water mixed and helps prevent acid layering. The mine-water pools in the Hazelton and Locust Gap mines overflow to drainage tunnels. The amount of vertical flow in the shaft is unknown, but is prob- ably significant. Slight differences in pH at depths within the pools of these mines were observed, but they are insufficient to indicate layering of the acid water. REFERENCE Felegy, E. W., Johnson, L. H., and Westfield, J., 1948, Acid mine-water in the anthracite region of Pennsylvania: US. Bur. Mines Tech. Paper 710. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—83 TABLE 1.—pH of water at different levels below surface of mine-water pools in anthracite fields of Pennsylvania Altitude of Altitude of Altitude surface of sampling Sampling point of collar mine-water point of shaft pool Date 01' Sample (feet above pH Remarks (feet above (feet above sampling number or below Mine Shaft sea level) sea level) sea level) Northern anthracite field Exeter ........... Red Ash. . . . 580 485 Jan. 9, 1961.. . 1 460 680 Pool formed after 1949 and ' 2 330 6.85 was pumped to prevent over- 3 200 6.85 flow until about July 1959. 4 60 6.65 Clear-spring ....... Clear-spring. 578 528 Jan. 4, 1961 . . 1 503 6.85 When mine was in operation, 2 473 6.75 the pH of pumped discharge was 6.5 on May 27, 1941. Pool formed before 1944; not pumped since. Schooley .......... N0. 1 ....... 558 423 Jan. 9, 1961 . . 1 398 6.40 When mine was in operation, 2 278 6.20 the pH of pumped discharge 3 158 6.40 was 6.7 on May 23, 1941. 4 33 675 Pool formed after Jan. 1951. Pumping ceased July 1959. South Wilkes-Barre. No. 5 ....... 589 89 . .do ......... l 64 7.10 When mine was in operation, 2 —61 3.65 the pH of pumped discharge 3 —236 4.00 was 5.1 on Klay 19, 194]. 4 ——411 4.10 Pool formed after June 1958. No 7 ............. N0. 2 ....... 545 508 Jan. 10, 1961.. 1 473 6.90 When mine was in operation, 2 335 6.25 the pH of pumped discharge 3 185 6.50 was 3.2 on June 10, 1941. 4 72 6.35 Pool formed after May 1954. Henry ............ Red Ash. . . . 561 448 April 20, 1960. 1 438 7.35 When mine was in operation, 2 348 6.00 the pH of pumped discharge 3 148 5.10 was 3.9 on May 15, 1958. 4 — 162 5.30 Pool formed after Jan. 1959. Shaft destroyed June 1960. Eastern middle anthracite field 1 Hazelton .......... Hazelton. . . . 1,580 1,091 Nov. 13, 1957. 1 1,070 3.20 2 900 3.40 Water rises in shaft and over- 3 750 3.20 flows through drainage Jan. 10, 1961.. 1 1,066 3.60 tunnel at altitude 1,091 feet. 2 955 3 .80 3 848 3 .60 Western middle anthracite field Locust Gap ........ Locust Gap. . 1,284 797 Jan. 11, 1961 . . 1 772 4.55 Mine-water pool overflows 2 647 4.50 through drainage tunnel at 3 522 5.85 altitude 747 feet. 4 284 5.50 Reliance. . . . . . . . . . . Reliance ..... 1,058 979 Jan. 12, 1961 . . 1 954 6.10 When mine was in operation, 2 756 5.85 pH of pumped discharge was 3 555 5.65 2.7 on Sept. 18, 1941, and 4 356 5.95 4.0 on Sept. 23, 1946. Water pumped sporadically from shaft. Packer No. 5 ...... No. 5 ....... 1,108 963 Jan. 13, 1961. . 1 938 6.70 When mine was in operation, 2 678 6.55 pH of pumped discharge 3 318 6.70 was 4.9 on Sept. 16, 1941. 4 58 6.55 Pool formed after Sept. 1957. B—84 GEOLOGICAL SURVEY RESEARCH 1961 TABLE 1.——pH of water at difl'erent levels below surface of mine-water pools in anthracite fields of Pennsylvania—Continued I 1 1 1 1 1 1 Altitude of 1 i Altitud< ol 1 1 1 Altitude surla< e of 1 1 52111111111111 1 1 '- ‘ ' ‘ I' ~ 11- t ‘ 1 1 t bamplmg 1101M #__M V 1 (1)11'leial1: "unsold? or i Date 111' 1 Sample llfliktltitlll111v< 1 pH , Remarks '"Wiu'iii V'TT‘TVA—M (feet above (fut above ‘ sampling 1 number or below i ‘ Mine Shaft 1 sea level) sea level) 1 1 sea 1 11 | Southern anthracite field 1 1 g :7 W 7 #7 N- .,-_#_. Greenwood ........ \o. 10 ...... i 1,002 452 Jan. 12, 10151.. 1 1 427 i 4.20 1 When mine was in lopemtmn, 2 372 4.00 ‘ p11 of pumped d1sclnu'gc 1 3 172 3.75 was 3,0 on July 2, 111-11, 1 1 42 2,80 and 3.1 (1110M. 15, 111411. ‘ 1 Pool formed after May 1960. I 1 Pumping at shaft ceased i 1 l ‘ Nov. 1960. 1 5% 38. ANGULAR UNCONFORMITY SEPARATES CATSKILL AND POCONO FORMATIONS IN WESTERN PART OF ANTHRACITE REGION, PENNSYLVANIA By J. PETER TREXLER, GORDON H. WOOD, J R., and HAROLD H. ARNDT, Washington, D. C. Geologists working in Pennsylvania generally have thought that the Pocono formation rests con- formably on the Catskill formation, although Willard (1939, p. 19—21) believed a disconformity intervenes in northern Pennsylvania. The present authors, mapping in the western part of the Anthracite region in eastern Pennsylvania, found that the contact is a regional, low- to high-angle unconformity in an area of more than 600 square miles. At most localities in the western part of the An— thracite region (fig. 38.1) the predominantly red, main body of the Catskill formation is overlain by an upper gray member that consists chiefly of gray and green sandstone, shale, and conglomerate, with local interbeds of red sandstone and shale. This gray member, which ranges in thickness from 0 to 2,400 feet, is absent at some localities north and northeast of Pine Grove (fig. 38). The overlying gray Pocono formation is composed mainly of sandstone and conglomerate, and ranges in thickness from 700 to 1,200 feet. The basal unit is a widespread pebble conglomerate, perhaps the Griswold Gap conglomerate of White (1883, p. 47— 52), which ranges in thickness from 2 to 100 feet. Because of the similarity between the gray beds in the upper part of the Catskill formation and beds of the Pocono formation, White (1883, p. 49—52) recognized a “Pocono-Catskill transition group.” This “transition group” is designated as the gray member of the Catskill formation in this report. White further stated that a geologist would assign the gray beds to the Pocono at one locality and to the Catskill at another, depending on the presence or absence of red beds. Although other geologists generally placed the contact between the Catskill and Pocono formations at the top of the uppermost red bed, the present investigation confirmed that the red beds in the gray member are of local extent and that the contact, where placed at the top of the up- permost red bed, was at different stratigraphic po- sitions at different localities. Therefore, the writers followed White (1883, p. 46—49) in placing the con- tact between the Catskill and Pocono formations at the base of the widespread pebble conglomerate, which locally rests on red beds or gray sandstone in the gray member or on the red, main body of the Catskill formation. EVIDENCE FOR THE UNCONFORMITY Three miles southeast of Lykens, near the nose of the J oliet anticline, the gray member of the Catskill . formation attains its maximum thickness of about 2,400 feet (fig. 38.2). To the west, on both limbs of the anticline, the upper 2,000 to 2,300 feet of the SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—85 76°45 76° 15' < < V V E- ‘I- E E z 2 E ”5 >3 3 s a E E a 01 3 .2: [PMr O m C \ a» 5’ E E Mount Carmelo \ ?\ Q&%\) < m 3: QOV’ \X‘ W i w \ /\3‘L a w / > C5 3: / a: i < MD g 2 WESTERN MIDDLE 40°45, H “3 .EL'NE MOUNTAIN 5 5 ._ ___ —— \_ ,. ., z Mch E A: E z: < 3 , V D . j r: a 0’ Pottsvflle E E ,. Minersville°l§ g % a :2 H < <1 5 ‘3; W D :9 m P . a O z / .4 o ‘4 a. D- / , ‘/ . 7 Mch Pillow ,/ ’ C16 / .- ’ / ’ \“90 l>~ PM, ,—2 ? MD 6' _/ (D Od\01) . .P‘\“ F“ a ONIr -1 w 6* Q RN m z /\ THE m in: 4/ < SOU n: g lPMr \00 E >. 00 \ N DC 5 ’1 O/VQ; 2 Williamstown0 7)" L Tower City Lykens AREA OF _.' ARGE SCALE MAP \ :. : / 3’ Pine Grove n'\ \_l Elizabethvilleo 7 ' Mch (5):. 1:1; 0 . ‘ I find“ .' N» Mch ." Mp ' ‘ 5 o 5 MILES 1 a J 1 DC , , ‘ 40°30' //' // M EX PLA N ATI ON 2 N Z <( S 2 Conformable contact l & <1 IPMr I _ o 3 _ _ _. —~ l g E > Unconformable contact, no angularity Post-Pocono rocks l (7) g observed g E xxxnxxx '1 Unconformable contact, angularity observed Mp 5 between the basal conglomerate of the E E Pocono formation and the gray member : g Pocono formation 0. of the Catskill formation 3 57. a .3 § g3 .......... 1 Mch 3 Unconformable contact, basal conglomerate E ‘ , ' — of the Pocono formation rests on the red (:ray member of the Catskill formation 2 main body of the Catskill formation N ’ Z _A g g I L Dc 3 -———‘—- § § A- t 5 Fault, showing relative horizontal b :7. i Main body of the Catskill formation > movement Q l and older rocks 3 PENNSYLVANIA MAP AREA FIGURE 38.1.—Map showing angular unconformity betweenhthe Catskill and Pocono formations in the western part of the Anthracite region, Pennsylvania. GEOLOGICAL SURVEY RESEARCH 1961 B—86 .am .2813 mo 53% sown—«5.8m “Egon wfi mo 83050350 Ewan o5 was :oSsEnom :Emano 23 mo 33:38 3% cc: 5933 20333 #2595 uEBosm 533% 23383 can 5:: omuofiowUlINwm 959% y%\ nos. x25 62 :5: mm! hvoen \Ii\ .wnEwE )EU .. 3x . as. \ NUDE av. . . 22% em on. u u on mfzfi O $\\o gas. :25 boaJoom \ \\ \ .maEuE >50 \ \ \\ \ \\ ¢® \ \ \\ 9 40 2.17 \Wm\ \ o \2% 9 Z a .. z . \/ \ \ 9< quZ uwad OOVN .wnEwE )30 7: An; 22 OZ 9., R. ‘ cosflie :EBNO 9: .«o 3.8 Eu: 3 \ g \Ewig\\\\§ M a s \ 3 .55 Ar 0 Qseuck 2: \o ngfisgg N33 ‘3 m "W . \‘ W Egaafimae fig: 5:: wusfivfi‘e 3:: @335 m. I" E\ N :ofiafiuow Exmaao 23 We 52:85 >80 u mun: :znu w ‘ 55$:qu 880m 2: we SEES—ago imam 1 a w S m. M. s 5 d 55.253 ocouom 2: we $3 Ea: M 4 d5; (mm . w m. ._ /v M E M Q\ a d r n .2 / \\\ a a a 3 M u... //I \\\\ m p. m N s m ‘ W M H w B 3—8.. osouomyamom 9 wNv W W cw .A W % m um m m o m a m E n o n w w w v d W H 3 e m. H W ulv m. N I. m. u o v N u 3 m N ,A 0 U ZO_F _ DJ 0. g 0 Warsaw limestone u) U) I Z El 9 El ]8 E MAP AREA Fort Payne formation 2 Pre«Chattanooga units 0: 9 Reefs in black 0 > o 1 2 3 4 5 MILES |_.I__J__l_l__'_l 37°00'— 36°45’~ FIGURE 39.1.f0utcr0p pattern and stratigraphic position of reefs in the Fort Payne formation, in part of south-central Kentucky. B—90 main body of the reefs, characteristically is cross- bedded at steep angles. Dips of crossbeds may ex- 1 ceed 20°, though dips of 8° to 10° are more com- mon. The inclination of crossbedding nearly every- where is to the south. Limestone in the reefs commonly is coarse grained, arenaceous and argillaceous, and gray to bluish gray. Fossils are common in coarse-grained limestone, less abundant in fine-grained limestone. Large crinoid stem segments are particularly abundant; in places the reefs are essentially a “crinoid hash.” Brachiopods and bryozoans, though not as abundant as crinoids, are common. Chert lenses and pods, quartz geodes, and small irregular masses of pale- blue chalcedony less than an inch in diameter are abundant in parts of the limestone as well as in the nearby siltstone and shale. Near the reefs, especially in laterally equivalent beds, the siltstone and shale are much more calcareous and darker than elsewhere in the formation. Petroleum and natural gas have been produced from limestone reefs in the Fort Payne formation GEOLOGICAL SURVEY RESEARCH 1961 in Wayne County southeast of the area of the present study and in parts of Hart, Barren, and Metcalf Counties to the northwest of the area. Local names have been given to the producing horizon in nearly every oil pool in these counties, but the pro— ducing horizons are also widely known as the “Beaver sand” or “Beaver Creek sand.” The present produc- tion of petroleum and natural gas from reef lime- stone in the Fort Payne formation in Kentucky has been small in comparison with production from rocks of Ordovician age. It is likely that additional knowledge of the size, trend, and physical properties of the reefs will assist in future exploration. REFERENCES Butts, Charles, 1922, The Mississippian series of eastern Ken— tucky; Kentucky Geol. Survey, Series 7, vol. 7, 188 p. Klepser, Harry J., 1937, The Lower Mississippian rocks of the Eastern Highland Rim; Ohio State Univ. Abstracts, Doc. 24, p. 181—187. Stockdale, Paris 8., 1939, Lower Mississippian rocks of the East-Central Interior; Geol. Soc. America Spec. Paper 22. 6% 40. THE TUSCALOOSA GRAVEL IN TENNESSEE AND ITS RELATION TO THE STRUCTURAL DEVELOPMENT OF THE MISSISSIPPI EMBAYMENT SYNCLINE By MELVIN V. MARCHER, Nashville, Tenn. Work done in cooperation with the Tennessee Division of Geology The Tuscaloosa gravel of Late Cretaceous age occurs as outliers capping many of the hills and ridges on the Western Highland Rim of Tennessee. In the southwestern part of the Rim a maximum thickness of 150 feet has been preserved; elsewhere the thickness is 30 feet or less. On the basis of its lithologic characteristics the Tuscaloosa can be subdivided into a western and eastern facies. Of the two, the western facies is more widespread and is typical of the formation over most of the area. The eastern facies is re- stricted to a narrow northward-trending belt along the eastern margin of the Western Highland Rim. LITHOLOGIC CHARACTERISTICS Size analyses indicate that the western facies of the Tuscaloosa gravel is a mixture of three distinct sedimentary components. Frequency curves show separate peaks for gravel, medium sand, and fine sand. The gravel component (larger than 13 mm in diameter) consists mainly of chert plus a small amount of sandstone. Much of the chert gravel was derived from formations of Devonian (Camden chert) and Mississippian (Fort Payne, Warsaw, and St. Louis formations) ages. Sandstone pebbles, although rare in the Tusca— loosa gravel, are relatively widespread. These peb— SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 bles are not indigenous to the area and did not come from formations now exposed in western Tennessee. Most of the sand in the western facies consist of angular chert and quartz grains. These grains, par- ticularly the chert, resemble partly weathered Cam— den and Fort Payne chert that has been mechanically crushed. All samples studied contain very minor amounts of rounded and frosted quartz sand which, like the sandstone and quartz pebbles, did not come from rocks now exposed in the area. Kaolinite, montmorillonite, and mica are present in all samples analyzed. Kaolinite is dominant (20 to 40 percent of total sample) in all samples except one, which contains 20 to 30 percent montmorillonite. In all other samples montmorillonite makes up 10 percent or less of the total sample. ' The eastern facies of the Tuscaloosa gravel con- tains all the components of the western facies and in addition contains beds of well-sorted sand and gravel, siliceous siltstone containing fragmentary plant fossils, heavy minerals, and an abundance of quartz sand and quartz pebbles. The contrast in sorting, lithologic diversity, and mineral content in- dicates a marked difference both in source and de- positional environment. SOURCE The pebbles of Mississippian chert are clearly of local origin. The Camden chert is present only in the Western Valley of the Tennessee River and in the subsurface farther west. Thus pebbles of the Camden chert in the Tuscaloosa have been trans- ported 10 to 50 miles from the west. Because pebbles of the Camden chert were trans- ported from the west, the sandstone pebbles, which are thoroughly intermixed in the main mass of the Tuscaloosa gravel, must have been transported from that direction also. The most probable source beds for the sandstone pebbles include the Lamotte and Roubidoux formations, which were exposed in west- ern Tennessee during Tuscaloosa time (Grohskopf, 1955, p. 14—16 and pl. 3). Angular chert and quartz grains seem to have been developed by attrition of Camden and Fort Payne chert during transport. The rounded and frosted quartz-sand grains in the main mass of the gravel probably were derived from the St. Peter or Dutch Creek formations, which formerly cropped ‘ out in western Tennessee and western Kentucky. B—91 Kaolinite and montmorillonite are both developed by weathering of the Camden and Fort Payne chert. Thus these components are of both local and distant origin. Some of the montmorillonite could have de- veloped by alteration of volcanic glass which also occurs in the fine fraction of the Tuscaloosa. Because the quartz pebbles so abundant in the eastern facies of the Tuscaloosa are not mixed throughout the main mass of the gravel as they should be if they had come from the west, it is in- ferred that they were derived from some other direc- tion. The most probable source was Pennsylvanian bedrock in northwestern Mississippi and western Kentucky. The beds of well-sorted sand and heavy minerals associated with the quartz gravel may also have come from the same areas. PALEOGEOLOGY AND PALEOGEOGRAPHY DURING TUSCALOOSA DEPOSITION The western facies of the Tuscaloosa gravel is probably a series of coalesced stream deposits be- cause the deposits lie at the base of a transgressive marine sequence; because of the apparent lack of significant chemical difference between the source areas and the deposits; and because of the textural similarity between the deposits and typical valley— fill deposits. The eastern facies of the Tuscaloosa may represent shoreline deposits where waves and currents win- nowed the stream-transported sediments from the west and brought in additional components from the north and south (fig. 40.1). As demonstrated by the source of some of the Tuscaloosa gravel components, the area west of the Western Highland Rim was a highland during Late Cretaceous time. Paleogeologic maps of the northern Mississippi Embayment (Freeman, 1953, pl. 3, Cap- lan, 1954, pl. 4, and Grohskopf, 1955, pl. 3) show that this topographic highland was also a structural high and that beds as old as Cambrian were exposed on its crest. This structural feature, first postulated by Wilson (1939), has been named the Pascola arch by Grohskopf (1955, p. 25). Reconstruction of the Pascola arch based on stream gradients estimated from the maximum size pebbles in the Tuscaloosa gravel and eastward thickening of post-Tuscaloosa sediments indicates that the arch stood nearly 1,000 feet above sea level during Tus- caloosa deposition. More than 8,000 feet of strata had been eroded from the crest of the arch by the beginning of Tuscaloosa deposition. B—92 GEOLOGICAL SURVEY RESEARCH 1961 ILLINOIS MISSOURI 0 /‘30 < LLl (I) < (D 8 2' O (I) D |... / S3/3 r N PENNSYLVANIAN MISSISSIPPI O 50 100 MILES | I l l l l J CONTOUR INTERVAL 100 FEET FIGURE 40.1.—Pa1eogeology and paleogeography of western Tennessee and adjoining areas during Tuscaloosa deposition. Contours show topography of Pascola arch. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 DEVELOPMENT OF THE MISSISSIPPI EMBAYMENT SYNCLINE During and shortly after deposition of the Tus- caloosa gravel the Pascola arch began to subside. Most of the subsidence occurred near the synclinal axis that generally follows the present course of the Mississippi. Superposition of the synclinal bend across the now-buried high resulted in faults that cut Paleozoic rocks and, in some areas, that extended upward into the overlying younger strata. B—93 REFERENCES Caplan, W. M., 1954, Subsurface geology and related oil and gas possibilities of northeastern Arkansas: Arkansas Div. Geology Bull. 20, 124 p. . Freeman, L. B., 1953, Regional subsurface stratigraphy of the Cambrian and Ordovician in Kentucky and vicinity: Ken- tucky Geol. Survey Bull. 12, 352 p. Grohskopf, J. G., 1955, Subsurface geology of the Mississippi Embayment of southeast Missouri: Missouri Geol. Survey and Water Res., 2d ser., v. 37, 133 p. Wilson, C. W., J r., 1939, Probable connection of the Nashville and Ozark domes by a complimentary arch: Jour. Geol- ogy, v. 47, no. 6, p. 583—597. ’5? 41. SYSTEMATIC PATTERN 0F TRIASSIC DIKES IN THE APPALACHIAN REGION By PHILIP B. KING, Menlo Park, Calif. Nearly 30 years ago Bucher (1933, p. 351-353) observed that a promising field for tectonic research would be the Triassic dikes that traverse the rocks of the Appalachian region in the eastern United States. The present note reaffirms this observation, and indicates new data that have become available since the time of Bucher’s writing. During preparation of a revised tectonic map of the United States (Cohee and others, 1961 in press) it was decided that these dikes were an item of suffi- cient tectonic interest to be plotted on this edition of the map. Their map pattern was therefore com— piled from all published sources; in addition, unpub- lished data for North and South Carolina were con- tributed by W. R. Grifiitts and W. C. Overstreet, and for New England by John Rodgers. NEWARK GROUP AND ASSOCIATED FEATURES Sedimentary rocks of the Newark group of Late . Triassic age form elongate strips of outcrop from Nova Scotia southwestward along the strike to South Carolina. Probable subsurface extensions of the Newark group farther east and south are also known from drilling and from geophysical surveys. The nature and occurrence of the Newark group has been summarized recently (Reeside and others, 1957, p. 1459—1461; McKee and others, 1959, p. 12, 13, 18, 24, pls. 4, 5, 7, 9). The extent and pattern of the present outcrop areas of the Newark group are determined largely by normal faults, along which the Newark has been dropped against older rocks on one or both sides. Present outcrop areas may have nearly the original extent of the deposits, as the nature of deposits adja- cent to the major bordering faults indicates that these were in process of displacement during sedi- mentation. However, the major faults and the nu- merous minor faults continued to be displaced after the close of the depositional epoch. Trends of faults and outcrop areas conform grossly to the northeast- ward strike of the older rocks, which had been pro- duced‘ by deformation of the Appalachian region prior to Late Triassic time. Also, the larger strips of outcrop of the Newark group are paired on each side of the central axis of the Appalachian deformed belt, with the faults which border them dropped antithetically toward the axis (McKee and others, 1959, p. 24, pl. 9). Newark sedimentation was accompanied by much igneous activity. Interbedded with the sedimentary rocks in the northern outcrop areas are flows of mafic lava. Both here and in outcrop areas farther south the sedimentary rocks are intruded by exten- sive stocks and sills of igneous rock, mostly classed as diabase, but including other mafic varieties. Even more abundant are the dikes, discussed below, which extend far away from the Newark areas. At least some of the intrusives are related to the lava flows and faults, but the age of others can be determined only within wide limits. Possibly these intrusives B—94 formed during a long time span, but they appear to be so closely related, not only among themselves but to the other features associated with the Newark group, that they all must be broadly of Late Triassic age. DIKES Narrow steeply dipping mafic dikes intrude the Newark group in all its outcrop areas and in places branch from the larger intrusives. ’They also extend into the surrounding older rocks and are common even far distant from the Newark outcrops. Most of the outlying dikes intrude the metamorphic and GEOLOGICAL SURVEY RESEARCH 1961 plutonic rocks of the Piedmont province, although a few extend northward into the Paleozoic rocks of the Valley and Ridge province near Harrisburg, Pa. Southeastward, many dikes extend to the edge of the Atlantic Coastal Plain, where they pass un- conformably beneath Cretaceous and younger strata. The dikes have been observed and located mostly as an incident to other geological investigations, and have seldom been a specific field of study, so that many morepdata regarding them could still be ob- tained. The accompanying map (fig. 41.1) reflects this present state of information. The abundant dikes shown in Pennsylvania and Maryland were EXPLANATION ,li' Diabase dikes of Triassic age Mainly in Piedmont province (>prszth- ian region; unwrapped in many areas \\\‘ Outcrops of Newark group of Late Triassic age Mainly sedimentary rocks but including intrusive stocks and sills in most areas, and interbedded lava in some northern areas 7 N ormal faults At borders of areas of outcrop of Newark group Boundaries of major geologic provinces 285° ,. \ fl 1 % V R) C) Q ft 1,439 3oo MlLES FIGURE 41.1.—Sketch map of the Appalachian region of the eastern United States, showing known occurrences of dikes of Triassic age, and areas of outcrop of the Newark group. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIG SCIENCES, ARTICLES 1-146 mapped in detail many years ago, and those in Georgia more recently by Lester and Allen (1950). Very few dikes, by contrast, are shown in North Carolina. Here, in a 30-mile segment of the Deep River basin, Reinemund (1955, p. 54—61, pls. 1, 4) mapped hundreds of transverse dikes, yet the geologic map of North Carolina (Stuckey, 1958) shows no dikes in the segments of the basin on either side. Probably some dikes, perhaps many, occur in these other segments, but are so far un— mapped. The dikes are sufiiciently known, however, to per- mit significant generalizations regarding their pat- tern. Although dikes of different trends cross or intersect, most dikes locally have a common trend. However, these local common trends vary systemati- cally from one part of the Appalachian region to another. In the southwestern 400—mile segment of the Appalachians, from Alabama to North Carolina, the dikes trend consistently northwestward (fig. 41.1). In southern Virginia the trend changes to north-northwestward and in northern Virginia to northward. Across Maryland and Pennsylvania the northward trend changes to northeastward, and this same trend continues into New England. The trends of the dikes are everywhere discordant to the trends of the structures of the enclosing rocks, and they are everywhere straighter than these struc- tures. In the southwestern 400-mile segment of the. Appalachian region the dikes extend nearly at right angles to the trends of the outcrop areas of the Newark group and the associated faults, as well as to the strike of the older rocks. Farther northeast- ward they cross the structures in the Triassic and older rocks diagonally. Moreover, in Pennsylvania and adjacent States, the dikes are not deflected by the marked sinuosities in the trend of the Newark rocks and their associated faults. INTERPRETATION Dikes, stocks and sills, normal faults, and sedi- mentary basins all formed in the Appalachian region during Late Triassic or closely related times, and are manifestations of a stress pattern, or succession of stress patterns, which existed in the region during those times. Dikes are products of regional tension directed horizontally in the crust (Anderson, 1951, p. 30). Those in the Appalachian region, which cut cleanly through all other structures, probably reflect the deep-seated tensile stresses that existed during Late Triassic time. In the southwestern segment they in- dicate that the trend of the axis of greatest tension, B—95 or of least compressive stress, was to the northeast, but in the northeastern segment this axis curves in an arc to the east, and finally to the southeast. A different pattern is shown by the normal faults and sedimentary basins of the Newark group. These follow closely the strike of the older rocks amidst which they lie, and may have been conditioned by fracture and displacement along existing lines of weakness. Pairing of the major basins and asso— ciated faults on opposite sides of the central axis of the Appalachians suggests that this axis was again raised into a broad arch during Triassic time. Differences between the stress pattern suggested by the dikes and that by the faults and sedimentary basins are seemingly incompatible. Possibly the two patterns existed at slightly different times, but more likely the faults and basins are an expression of superficial stresses which were contemporaneous with the deep-seated stresses that produced the dikes. Be that as it may, the stress patterns of Late Triassic time in the Appalachian region appear to have been more systematic, and the tectonic history more complex than has generally been assumed. An eventful tectonic history of the region during Triassic time has also been suggested recently by Woodward (1957, p. 1437—1439), on the basis of other evidence and with a different interpretation. It would appear that further study of the Triassic phase of the tectonic evolution of the Appalachian region is warranted. The nature, history, and pat- tern of the Late Triassic dikes will be a useful tool in such studies. ' REFERENCES Anderson, E. M., 1951, The dynamics of faulting and dyke formation, with applications to Britain, 2d ed.: Edin- burgh, Oliver & Boyd, 206 p. Bucher, W. H., 1933, The deformation of the earth’s crust: Princeton, N. J., Princeton Univ. Press, 518 p. Cohee, G. V., and others, 1961, Tectonic map of United States: U.S. Geol. Survey (in press). Lester, J. G., and Allen, A. T., 1950, Diabase of‘ the Georgia Piedmont: Geol. Soc. America Bull., v. 61, p. 1217—1224. McKee, E. D., and others, 1959, Paleotectonic map of the Triassic system: U.S. Geol. Survey Misc. Geol. Inv. Map I—300, 33 p., 9 pls. Reeside, J. B., Jr., and others, 1957, Correlation of the Triassic formations of North America, exclusive of Canada: Geol. Soc. Ameriaa Bull., v. 68, no. 11, p. 1451—1513. Reinemund, J. A., 1955, Geology of the Deep River coal field, North Carolina: U.S. Geol. Survey Prof. Paper 246, 159 p. Stuckey, J. L., 1958, Geologic map of North Carolina: North Carolina Dept. Conserv. Dev., Div. Mineral Resources. Woodward, H. P., 1957, Structural elements of northeastern Appalachians: Am. Assoc. Petroleum Geologists Bull., v. 41, p. 1429—1440. 62‘ B—96 A GEOLOGICAL SURVEY RESEARCH 1961 42. RAINFALL AND MINIMUM FLOWS ALONG THE TALLAPOOSA RIVER, ALABAMA By H. C. RIGGS, Washington, D. C. A major problem in hydrology is the estimation of the frequency distribution of an event such as a flood or drought. Ordinarily this is obtained by some analysis of the recorded events. Frequently one or more of the recorded events appear unusual with respect to the others and the proper interpreta- tion is not apparent. This is the problem posed by the annual minimum flows for the Tallapoosa River at Wadley, Ala., for 1924—1955 as shown on figure 42.1. The three lowest points (fig. 42.1) appear “out of line” with the others, particularly if a typical fre- quency curve that flattens at the low end is postu- lated. Several explanations are possible: the actual recurrence intervals of these three minimum flows are much greater than indicated by the period of record; the three lowest minimum flows are lower than natural flows because of emergency withdrawals upstream; or the frequency curve should be concave downward instead of concave upward. To choose the correct explanation, additional in- formation is needed. The minimums occurred in 1925, 1931, and 1954. It is unlikely that the first two were affected by emergency withdrawals of water because water requirements were not great in the earlier years. Much additional information would be required to define the shape of the frequency curve. This leaves only the possibility of making 1000 ‘- u. o.- 100 ANNUAL MINIMUM 7~DAY AVERAGE DISCHARGE,IN CFS 10 1.1 2 5 10 20 50 RECURRENCE INTERVAL .IN YEARS FIGURE 42.1.—Drought frequency plot, Tallapoosa River at Wadley, Ala. o Gadsden oTaIIadega o Wadley Auburn O o 10 20 3o 4OMILES |_ I l J I FIGURE 42.2.—Map of Tallapoosa River basin above Wadley, Ala., showing location of long-record rainfall stations. better estimates of the recurrence intervals of the three lowest discharges. If it could be shown that extremely low annual minimum flows coincide with extremely low precipi- tation, then the rainfall record could be used to indi- cate Whether lower minimum flows had occurred in the longer period covered by the rainfall record. Four rainfall records near the Tallapoosa River basin are SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—97 500 100 ACTUAL DISCHARGEJN CFS Arithmetic model .,_/ Semilog model 50 100 500 50 100 500 COMPUTED DISCHARGE , IN CFS FIGURE 42.3.—Comparison of discharges computed by two equations with actual discharge. available for the period 1888—1955. These records are used in the following analysis. The principal factors affecting the magnitude of an annual minimum flow are the amount and dis- tribution of precipitation during the year or part of the year. For this study the winter, spring, and early summer precipitation is considered an index of the relative amount of ground water available to the stream on July 31, and the August-September precipitation an index of the opportunity for deple- tion of this ground-water supply. Locations of long-rainfall-record stations in the vicinity of the Tallapoosa basin are shown on figure 42.2. Comparison of these rainfall records showed that no two agreed very well in the summer months because of the irregularity of thunderstorm activity. Therefore, all four records were used. The two in- dexes selected are January-through-July precipita— tion in percent of normal and August-September pre- cipitation in percent of normal. These percentages were computed for each rainfall record and then averaged over the four records to obtain the index values. Annual minimum flows were related to the two precipitation indexes by standard regression methods using two models, one arithmetic and one semilog. The regression equations are Q = 356 + 12(JJ) + 43 (AS) and log Q : 2.49 + 0.023 (JJ) + 0.079(AS) where Q is the annual minimum 7-day average dis- charge, (JJ) is the January-through-July precipita- tion index, and (AS) is the August—September pre— cipitation index. Plots of computed values of Q against actual values for both equations are shown on figure 42.3. The results appear similar except that the arithmetic model fits the three low points better. Both equations were solved for Q using rainfall indexes from 1888 to 1955, and the results are plotted on figure 42.4. These plots indicate that the three lowest minimum flows in the period of stream- flow record 1924—1955 probably were also the lowest in the period 1888—1955. Therefore, the recurrence intervals assigned to these flows are recomputed on the basis of a 68-year period (1888—1955) rather than a 32-year period (1924—1955). The points as originally plotted and the three adjusted points are shown on figure 42.5. A straight line is a reasonable interpretation of the frequency relation if the ad- justed points are used. B—98 500 — 200 Arithmetic model 100 500 “‘— 200 COMPUTED DISCHARGEJN CFS Semilog model 100 50 ‘ 1880 1 900 1920 1940 YEAR 1960 FIGURE 42.4.—Annua1 minimum 7-day average discharges for Tallapoosa River at Wadley computed by two equations. The equations indicate that greater than normal January-through-July precipitation virtually pre- cludes a very low annual minimum. Both precipita- tion indexes must be low in order to obtain an ex- tremely low annual minimum flow. The method outlined here is restricted to streams having their minimums in the late summer. The indexes used are rather rough and undoubtedly the regression could be improved by use of more ap- propriate ones. A model is needed to account for GEOLOGICAL SURVEY RESEARCH 1961 the July, August, and September precipitation in a year in which the minimum occurred in September, and that would ignore the August and September precipitation for the year in which the minimum occurred in July. However, the results are suffi- ciently reliable to demonstrate the usefulness of precipitation records for improving estimates of the recurrence intervals of very low annual minimum discharges. The method should be applicable to other streams having suitable basin characteristics, and having precipitation records for much longer periods than streamflow records. 0 From streamflow record c“; E 1000 [$1 X... (3 m0”... :0 ‘Q. C 22. Lu .0 o 0 2w 3% \ E5 100 u .0 z - s —1’ 0 O Era A < :> z z < 0 Based on precipitation records 10 1.1 2 5 10 20 50 RECU RRENCE INTERVAL, | N YEARS FIGURE 42.5.—Drought frequency curve based on both stream- flow and precipitation records, Tallapoosa River at Wad- ley, Ala. 'X‘ 43. STRESS MODEL FOR THE BIRMINGHAM RED IRON-ORE DISTRICT, ALABAMA By THOMAS A. SIMPSON, Arlington, Va. Open fracture systems associated with tight folds and major faults were observed to be the controlling factors that influenced the direction of ground-water movement in the red iron-ore mines of the Birming- ham district. The parallelism of the northeasterly trending folds and faults in the Birmingham red iron-ore district suggests a common origin as the result of compression from the southeast. The orien- tation of the joints in relation to the folds and faults suggests a second stress field that acted as compression from the south. The area is underlain by sedimentary rocks about 15,000 feet thick ranging in age from Cambrian to Pennsylvanian. These rocks have been folded into parallel and subparallel northeasterly trending anti- clines and synclines. The composite structure, the Birmingham anticline, is overturned to the north- west and cut by a low—angle thrust along its north- B—100 west margin. The Ishkooda-Potter fault system in the northern part of the district strikes N. 40°—50° E. and consists of high-angle reverse and normal faults. part of the district strikes generally N. 50° E. and consists of a large normal fault and several sub- sidiary faults. The Dickey Springs-Patton fault sys- tem strikes N. 44°—53° E. and consists of several high-angle normal faults and a major high-angle reverse fault. Some of the faults in the district show evidence of strike-slip movement at under- ground and surface exposures. The strikes of the joints and major structural fea- tures commonly observed in the district are shown on figure 43.1. Most of the joints trend from N. 2° E. to N. 68° W. or from N. 18°—90° E. The greatest concentration of joint sets lie within relatively nar- row limits from N. 20°—40° W. and from N. 30°— 70° E., which is parallel and subparallel to the strikes of the major folds and faults. The Shannon fault system in the central, GEOLOGICAL SURVEY RESEARCH 1961 The orientations of the folds, faults, and joints can be explained as the result of two separate stress fields acting in the area. The initial stress field (F1) originated as compression from the southeast. This stress field produced the northeasterly trending folds and thrusts, and the conjugate joint systems indicated on figure 43.1. The second stress field (F2) originated as com- pression from the south and produced strike-slip movement along preexisting northeasterly trending fractures. Joint systems formed in this field are rotated counterclockwise relative to the first joint systems. The concentration of joints shown on fig- ure 43.1 can be explained as the overlapping of the joint systems formed in the two stress fields. The stress model just described accounts for the major structural features and for the jointing ob- served in the Birmingham district. 6% 44. WATER-TEMPERATURE DISTRIBUTION IN A TIDAL STREAM By FREDERICK W. WAGENER, Columbia, S. C. Work done in cooperation with South Carolina Public Service Authority Water-temperature and velocity observations were made in a tidal reach of Waccamaw River at Con- way, S. C. to determine and explain variations in water temperature during a tidal cycle. These ob- servations provided data for studying the vertical distribution of temperature, and for comparing the results with similar studies on nontidal streams. Other studies of temperature distribution in non- tidal South Carolina streams having velocities ex- ceeding 1.5 fps (feet per second) indicate little ver- tical variation in temperature. Temperature obser— vations were made at both 0.2 and 0.8 of the total depths at more than 300 vertical-profile stations and at each foot of depth at several dozen others, but at only a few of the stations was the temperature variation more than 01° F. The depth of the streams at these stations was as much as 19 feet and water temperature ranged from 54° to 92° F. The temperature, velocity, and depth observations discussed in this paper were made during a tidal cycle from 7 am. to 7:18 pm. on September 23, 1958. The temperature observations were made by lowering the small probe of an electric thermometer into the water to the desired depth. The stage, dis- charge, air temperature, and water temperature dur- ing the tidal cycle are shown on figure 44.1. Water temperatures were obtained periodically at the 0.2 and 0.8 depths at 16 stations across the stream, which provided a total of 113 pairs of ob- servations. For 72 of these pairs, temperatures were the same at 0.2 and 0.8 depths; for 21 pairs the tem- perature difference was 01° F; for 9 pairs the dif— ference was 02° F; and for the remaining 11 pairs the difference was greater than 02° F. Sixteen ad- ditional sets of water temperatures were obtained periodically at selected stations, observations being SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—101 I l I I I | 3.5 - -' l— LIJ LIJ L I E 3.0 - — ,_- I (5 a d I 2.5 - u] w < 0 2.0 — .1 m LI. 0 +1000 — — E u? g ._ < 0 " I o ‘9 a —1000 - - 85 - _. ’2 HM LIJ Z: ”-5 80 - - :1 DE Water 3% 75 .. Alr __ Ea: I—fi o 70 — — I I I I l I 8 AM. 10 AM. 12 M. 2 RM. 4 PM. 6 PM. FIGURE 44.1.——Physical conditions during tidal cycle. , made at each foot of depth. For 13 of these sets, the maximum variation in the vertical was 01" F; for the three remaining sets the variation was 02° F or more. Temperature differences that exceeded 02" F can be arranged in two groups. The first group comprises temperature differences observed at times of velocity less than about 0.25 fps, high solar radiation, and little or no wind. At these times, a minimum amount of turbulent mixing occurs and heating of the water near the surface by solar radia- tion is at a maximum. Such conditions favor a tem- perature differential. The greatest observed tem- perature difference resulting from the combination of these conditions is shown by the temperature profile for station 150 at 11:18 a.m. (fig. 44.2). A Second period during which relatively high temperature differentials occurred was 45 to 60 min— utes after high tide. Velocities at that time increased to 0.5 fps or more, which is usually sufficient to cause turbulent mixing. During this period, how— ever, it seems that a slug of warmer water released from storage passed by the measuring section. This warmer water probably originated either in an ex- tensive shallow borrow pit connected with the river 0.3 mile upstream or in Kingston Lake which is con- nected with the river 0.6 mile upstream. The tem- perature and velocity hydrographs, figure 44.3, show the effects of this warmer water. The difference in temperature between the 0.2 and 0.8 depths at 12 :10 B—102 p.m. was 0.8° F shortly after the direction of flow had changed from upstream to downstream, but within two hours the difference was again negligible. The results of the investigation indicate that when velocities exceed about 0.25 fps, turbulent mixing is sufficient to preclude temperature differences of l l l 2- _ A 4.. —J [— Lu Lu E Lu 0 < LI. 0: :> <0 6— _ 0: Lu l— < 3 3 O _l LIJ m :x: 8— - ’— u. m o 10- - E' mi . . I: U — _ O 0 .1 Lu > _.5' — .. 4 1 l I I 1 I 8 10 12 2 4 6 8 A.M. A.M. M. P.M. P.M. P.M. P.M. FIGURE 44.3.—Temperature and velocity observations at station 100. 5b SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—103 45. RECENT LEAD-ALPHA AGE DETERMINATIONS 0N ZIRCON FROM THE CAROLINA PIEDMONT By WILLIAM C. OVERSTREET, HENRY BELL, III, HARRY J. ROSE, JR., and THOMAS W. STERN, Beltsville, Md., and Washington, D. C. . Lead-alpha ages have recently been determined for 21 zircon concentrates separated from granite, granodiorite, and syenite exposed in the Piedmont of North and South Carolina. The location of the samples is shown on figure 45.1, and descriptions of the sources of the zircon are listed in table 1. Results TABLE 1.—Sources of the zircon No. on fig. 45.1 1. U.S. National Museum collection. Large zircon crystals stated to have come from a locality 4 miles east of Tigerville, Greenville County, S. C. Zircon-rich vermicu- lite deposits thought to be source of the specimen. Sample USNM 105674. 2. U.S. National Museum collection. Large zircon crystals from the Jones Mine, Henderson County, N. C. Ver- miculite-bearing syenite pegmatite. Sample USNM 80114. 3. Zircon panned from 200 pounds of saprolite of fine- grained massive granite exposed in deep road cuts 0.9 mile southwest of Blackjack, Fairfield County, S. C. Rock is marginal phase of pluton represented by sam- ple 59—OT—102. Sample was free of inclusions, but exposure shows blocky inclusions of amphibolite, biotite- hornblende schist, and feldspathic kyanite-muscovite schist. Sample 59—OT—107. 4. Zircon panned from 290 pounds of saprolite of massive biotite-granite exposed at the intersection of S. C. Rte. 20—19 and the Rockton-Rion Railroad 5.5 miles S. 20° W. of Winnsboro, Fairfield County, S. C. Sample 59— OT—102. . 5. Zircon panned from 260 pounds of saprolite of coarse- grained massive porphyritic biotite granite having phenocrysts of pink microcline up to 94 inch in length, exposed on S. C. Rte. 97 at a point 1.1 miles north of White Oak Creek, Kershaw County, S. C. Sample 59— OT—110. 6. Zircon panned from 180 pounds of saprolite of very coarse grained massive porphyritic biotite granite exposed on the east side of Lowrys—Baton Rouge road at a point 0.5 mile west of the junction with U.S. Rte. 321 near Lowrys, Chester County, S. C. Sample 59—0T—101. 7. Zircon panned from 220 pounds of saprolite of fine- grained massive biotite granite exposed in deep road cuts on both sides of the Leeds-Wilksburg road at a point opposite the Leeds Lookout Tower, Chester County, S. C. Sample 59—OT—100. 8. Samples from Isenhour Quarry on N. C. Rte. 73 about 0.5 mile east of Concord, Cabarrus County, N. C. Samples are composites of 20-pound samples taken from differ- ent parts of the body of rock. Source and sample no. of the analyses and the calculated ages of the zircon crystals are given in table 2. Radioactivity determinations on igneous or pyro- clastic rocks in the Piedmont offer the only means of determining the ages of these rocks, as the in- truded sedimentary rocks contain no fossils. The TABLE 1.——Sources of the zircon—Continued No. on fig. 45.1 Zircon panned from 60 pounds of saprolite of medium- grained biotite granite in the southern dike in quarry. Sample IPE. Zircon panned from 60 pounds of saprolite of biotite gran- ite forming the northern dike in the quarry. Sample IPF. Zircon panned from 100 pounds of saprolite at the main body of biotite granite. Sample IPG. Source and sample no. Zircon panned from 100 pounds of saprolite at the main body of biotite granite. Sample IPH. Zircon panned from 260 pounds of syenite in a dike cut- ting granite and gneissic granodiorite. Sample HB— 39—59. Zircon panned from 60 pounds of saprolite of gneissic granodiorite; both the granite and the syenite intrude the gneissic granodiorite. Sample IPA. Zircon panned from 40 pounds of saprolite of gneissic grandiorite. Sample IPB. Zircon panned from 40 pounds of saprolite of gneissic granodiorite. Sample IPC. Zircon panned from 40 pounds of saprolite of gneissic granodiorite. Sample IPD. . 9. Zircon panned from 340 pounds of saprolite of coarse- grained, massive augite syenite exposed in a quarry on the north side of N. C. Rte. 49 just west of the inter- section with U.S. Rte. 601 about 2.5 miles south of Concord, Cabarrus County, N. C. Sample 56—OT—11 and 56—0T—11a. 10. Zircon panned from 200 pounds of saprolite of porphyritic granite exposed on county road between Watts and S. C. Rte 71 at a point 2 miles south of route 71 in Abbeville County, S. C. Nonmagnetic fraction at 1.5 amperes in Frantz Separator; sample 59-OT—111 (NM. 1.5). Magnetic fraction at 1.5 amperes; sample 59—OT—111 (M 1.5). 11. U.S. National Museum collection. Large zircon crystals from gneiss exposed 4.5 miles east of Iva on the line between Anderson and Abbeville Counties or in Abbe- ville County, S. C. Sample USNM 97589. B—104 GEOLOGICAL SURVEY RESEARCH 1961 l] Sedimentary and igneous rocks of Triassic age in ~< Syenite Gabbro I < Brevard belt EXPLANATION Coastal plain rocks of Cretaceous and younger age Granite )r I Kings Mountain belt cgn Charlotte belt B Inner piedmonl belt < c I Carolina slate belt 50 MILES X1 Sample locality Blue Ridge belt Bu ° FIGURE 45.1.—Major rock units and location of zircon samples in the Piedmont of North and South Carolina. rocks studied are now saprolite, so that only resistant minerals can be used for age determinations. De- spite a lack of positive knowledge concerning the absolute ages of these rocks, many tentative ideas have been presented regarding their relative ages. Major syntheses of the regional geology of the Southeastern States evolved by Arthur Keith (1923, p. 309—380) and Anna I. Jonas (Mrs. G. W. Stose) (192-2, p. 228—243), though profoundly different in tectonic and stratigraphic interpretation, generally attributed a Precambrian age to the bulk of the metasedimentary rocks and to some of the plutonic igneous rocks. The massive igneous rocks were con- sidered to be late Paleozoic in age. Both Keith and Jonas recognized the polymetamorphic character of some ofthe schist and gneiss, and, despite differences in opinion as to the mechanics of the metamorphism, they attributed it to processes operating in Precam- brian and in late Paleozoic time. Recently another major synthesis of Appalachian geology has been presented by P. B. King (1951, p‘. 119—144; 1955, p. 332—373) _wh0 proposes that the metamorphosed sedimentary and volcanic rocks of the, Carolina Piedmont and the igneous rocks, intruded during several orogenic episodes, are Paleozoic in age. Recent geologic observations in the Carolina Pied- mont support King’s View (Kesler, 1944, p. 755— 782; Griffitts and Overstreet, 1952, p. 777—789; Kesler, 1955, p. 374—387; Overstreet and Griflitts, 1955, p. 549—577; Stuckey and Conrad, 1958, p. 3—51; Stromquist and Conley, 1959, p. 1—36; Bell and Over- street, 1959, p. 1—5; Long, Kulp, and Eckelmann, 1959, p. 585—603; Bell, 1960, p. B189—B191; and Overstreet and Bell, 1960, p. B197—B199). They show 3 sequences or episodes of sedimentation, volcanism, igneous intrusion, folding, and metamorphism. Ero- sional unconformities bracket the 3 episodes. The Paleozoic geologic events shown schematically in table 3 were deduced by Overstreet and Bell as a result of reconnaissance mapping during which it was recognized that the metasedimentary rocks of the South Carolina Piedmont consist of slate-belt rocks of various ages raised to different grades of regional metamorphism, and that unconformities in the slate belt correlate with unconformit1es in the Kings Mountain belt. ~ 1' ~ 1' - The unconformities correlated between the slate and the Kings Mountain belts are those below epi- sodes B and C, table 3. A postulated unconformity beneath episode A has not/been observed in the SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 TABLE 2,—Lead-alpha ages of zircon from rocks in the Piedmont of North and South Carolina [Alpha activity measurements by T. W. Stern; spectrographic analyses of lead by H. J. Rose. Jr., T. W. Stern, and H. W. Worthing.] Average lead Alpha content from counts per duplicate No. on Sample No. milligram determinations Calculated age 1 fig. 45.] per hour (parts per (millions of years) million) 1 USN M 105674 ...... 269 28 255 i 30 2 USNM 80114 ....... 439 51 280 i 30 3 59—0T—107 ......... 346 37 260 i 30 4 59—0T—102 ......... 477 53 270 i 30 5 59—OT—110 ......... 170 17 245 i30 6 59—OT—101 ......... 306 32 255 i” 30 7 59—0T—100 .......... 145 28 460 :t 50 8 IPE ................ 377 68 445 i 50 IPF ................ 458 68 360 i 40 IPG ................ 433 78 430 i 50 IPH ............... 398 49 300 i 35 HB—39—59 .......... 262 49 450 i 50 IPA ............... 132 28 505 i 55 IPB ................ 123 25.5 495 i55 IPC ................ 117 19 380i 100 IPD ............... 132 26 470 i 55 9 56—OT—11 .......... 24 3 .0 305] )425 i 110 56-OT—lla ......... 22 5.0 540] 10 59~()T—1 11 (NM 1.5) 344 82 565 i 65 59—0T—111 (M 1.5). . 481 102 505i55 11 USNM 97589 ....... 172 40 550 i60 1Lead-alpha ages (rounded to nearest 5 million years) were calculated from the equations : (1) t : C Pb where t is the calculated age in millions of years. C is a a constant based upon the U/Th ratio and has the value 2485, Pb is the lead content in parts per million and a is the alpha counts per milli- gram per hour; and (2) T = t —— 1/2 let2 where T is the age in millions of years corrected for decay of uranium and thorium, and k is a decay constant based upon the U/Th ratio and has a value of 1.56 X 10—4. U/Th ratio from X-ray fluorescence analyses by F. J. Flanagan is 1.0 for samples 59—0T—100, 59—0T—101, 59—OT~102, 59—0T—110, and 59—0T—111 (M 1.5) ; assumed 1.0 for other samples. Piedmont of southern North Carolina or in South Carolina. Some measure of the probable age of the unconformities and of the sedimentary and pyro- clastic rocks they bracket have been sought by the authors through the lead-alpha ages of zircons from plutonic igneous rocks emplaced during one or an- other of the three episodes listed in table 3. Many pounds of saprolite were panned to obtain each zircon concentrate. In addition, three samples of coarse-grained zircon were kindly given to the writers by G. S. Switzer of the US. National Museum. Direct measurements of the ages of the sediments in the three episodes is being attempted by A. A. Stromquist, A. M. White, and T. W. Stern by analyzing zircon from felsic lavas interbedded with the sediments. This work, however, is not yet completed. The results of lead-alpha age determinations on 17 of the 21 samples fall into three groups (table 4) B—105 which correspond to the position of their host rocks in the three geologic episodes shown on table 3. The analyses are most consistent and seem to show the best agreement with presently available field data in the youngest group of samples, and increasingly less consistent in the older groups. The results from four samples do not fit with the recognized field relations. One sample of zircon (59—OT—100) with an age of 460 i 50 my. (million years) was collected from fine-grained granite thought to be a marginal phase of the oval pluton represented by sample 59—OT—101 having an age of 255 i 30 m. y. The older sample may be contami- nated by nonradiogenic lead or by an dlder genera- tion of zircon. The samples of zircon from Cabarrus County, N. C., 56—OT—11 and 56—OT—11a (425 i 110 m.y.), HB—39—59 (450 i 50 m. y.), are thought to come from rocks occupying structural positions similar to the episode-C syenite. Low lead and alpha activity of the zircon from samples 56—OT—11 and 56—OT—1 1a make satisfactory analysis very difficult, but sample HB—39—59 was satisfactory for analysis, and it also gave an unexpectedly old age. Possibly some syenite was emplaced during episode B, but the field evidence presently restricts syenite to episode C. The probable ages of the unconformities between the three episodes can be interpreted from the three groups of ages shown on table 4. The unconformity between episodes C and B apparently formed between 400 and 260 my. ago. In order to allow for the deposition of the sediments in which episode-C syenite and granite is emplaced, the unconformity is probably closer to 400 than to 260 my old. It appar- ently was formed between Ordovician and Devonian time. The ages of the zircon crystals from rocks in epi- sode A doubtless are modified by loss of lead during the profound metamorphism of episode B. We do not yet know when these rocks were emplaced, but it is likely that they were intruded into sediments of late Precambrian and Cambrian age. The un- conformity between episodes B and A may have been formed between Cambrian and Ordovician time. REFERENCES Bell, Henry, III, 1960, A synthesis of geologic work in the Concord area, North Carolina, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400—B, p. B189—B191. Bell, Henry, III, and Overstreet, W. C., 1959, Relations among some dikes in Cabarrus County, North Carolina: South Carolina Div. Geology, Geol. Notes, v. 3, no. 2, p. 1—5. B—106 GEOLOGICAL SURVEY RESEARCH 1961 TABLE 3.—Summa1‘y of Paleozoic geologic events in the Carolina Piedmont Episode of folding, meta- R°°k Metamorphism morphism, Era and igneous activity Sedimentary Igneous Regional Contact Unconformity Syenite, gabbro, py- Syenite, gabbro, pyroxe- None attributable to roxenite, norite; nite, norite and granites syenite; feeble local granitic rocks, typi- unaffected by progres- contact effect from cally form circular sive regional metamor- gabbro, pyroxenite, plutons and elongate phism, but show some and norite; feeble in- cross—cutting bodies; retrogressive features crease in metamor- felsic and mafic flows chiefly resulting from phism at granite con- ' C and dikes associated cataclasis; felsic and tacts; no metamor— with the pyroclastic mafic dikes and flows phism attributable to and sedimentary show effects of low- felsic and mafic rocks. grade regional meta— _ feeder dikes. morphism. Argillite, graywacke, Progressive, seldom ex- pyroclastic rocks. ceeding greenschist facies; slight retro- gressive. Unconformity Paleozoic _ Granitic rocks, typically Widespread migmatiza- Granites of episode B concordant plutons; tion; retrogressive effects react retrogressivcly gabbro, pyroxenite, such as recrystallization on inclusions of gab- andesite dikes; mafic of biotite attributable bro and pyroxenite flows, and felsic dikes to episode C. of episode B; may and flows associated have large contact with pyroclastic and aureoles in green- sedimentary rocks. schist and albite- B epidote amphibolite Argillite, graywacke, Progressive, ranging from zones; little or no pyroclastic rocks, greenschist facies to aureoles in higher local sandstone and sillimanite—garnet sub— grade zones; no evi— limestone; now seen facies; retrogressive dence of metamor- as schists, gneisses, features attributable to phism induced by migmatites, quart- episode C locally com- feeder dikes for mafic zites and marble. mon; highest-grade and felsic flows; rocks show some re- retrogressive effects crystallization of biotite associated with the and retrogression of granites of episode C. sillimanite t0 sericite. Unconformity Granitic rocks. Apparently strongly meta— Relations essentially ? morphosed in episode B. unknown. Graywacke, pyro- Progressive, ranging from Late elastic rocks, local greenschist facies to Precambrian A limestone; now seen sillimanite-garnet sub- as schists, gneisscs, calc—s1llcate rocks; migmatites common. facies; locally retro— gresswc. Unconformity, widespread erosion Precambrian Basement unobserved in the Carolina Piedmont SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 TABLE 4.—Correlation of selected lead-alpha ages of zircon crystals Episode of folding, meta- morphism, Lead-alpha and igneous Rock Sample No. age activity (millions (table 3) of yearS) Unconformity below sedimentary rocks of Late Triassic age Syenite ............ U.S.N.M. 105674 ..... 255 :tSO Syenite ............. U.S.N.M. 80114.... . . 280 i30 Granite ............ 59—OT—107 .......... 260 i 30 Granite ............ 59—OT—102 .......... 270 i 30 Granite ............ 59—OT—1 10 .......... 245 i 30 Granite ............ 59—OT—101 .......... 255 i 30 Unconformity Granite ............ IPE ................ 445 i 50 Granite ............ IPF ................ 360 i 40 Granite ............ IPG ................ 430 i 50 Granite....... ......IPH .................... 300i35 Unconformity Gneissic granodiorite IPA ................ 505 :55 Gneissic granodiorite IPB- ................ 495 i55 Gneissic granodiorite IPC ................ 380 :t 100 Gneissic granodiorite IPD ................ 470 :55 Granite ............ 59-0T-111 (N.M. 1.5) 565 $65 Granite ............ 59-OT-111 (M 1 .5) 505 i 55 Gneiss ............. USNM 97589 ........ 550 i 60 Griflitts, W. R., and Overstreet, W. C., 1952, Granite rocks of the western Carolina Piedmont: Am. Jour. Sci., v. 250, p. 777—789. 46. B—107 Jonas, A. I., 1932, Structure of the metamorphic belt of the southern Appalachians: Am. Jour. Sci., 5th ser., v. 24, p. 228—243. Keith, Arthur, 1923, Outlines of Appalachian structure: Geol. Soc. America Bu11., v. 34, no. 2, p. 309—380. Kesler, T. L., 1944, Correlation of some metamorphic rocks in the central Carolina Piedmont: Geol. Soc. America Bull., v. 55, p. 755—782. ————, 1955, The Kings Mountain area, in Russell, R. J., ed., 1955, Guides to southeastern geology: Geol. Soc. Americ'a Guidebook, 1955 Ann. Mtg., p. 374—387. King, P. B., 1951, The tectonics of middle North America: Princeton, N. J ., Princeton Univ. Press, p. 3—203. , 1955, A geologic section across the southern Appala- chians: an outline of the geology in the segment in Tennessee, North Carolina, and South Carolina, in Rus- sell, R. J ., ed., 1955, Guides to southeastern geology: Geol. Soc. America Guidebook, 1955 Ann. Mtg., p. 332—373. Long, L. E., Kulp, J. L., and Eckelmann, F. D., 1959, Chronol- ogy of major metamorphic events in the southeastern United States: Am. Jour. Sci., v. 257, no. 8, p. 585—603. Overstreet, W. C., and Bell, Henry, III, 1960, Geologic rela- tions inferred from the provisional geologic map of the crystalline rocks of South Carolina, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400—B, p. B197—B199. Overstreet, W. C., and Griflitts, W. R., 1955, Inner Piedmont belt, in Russell, R. J., ed., 1955, Guides to southeastern geology: Geol. Soc. America Guidebook, 1955 Ann. Mtg., p. 549—577. Stromquist, A. A., and Conley, J. F., 1959, Geology of the Albemarle and Denton quadrangles, North Carolina: Carolina Geol. Soc., Field Trip Guidebook, p. 1—36. Stuckey, J. L., and Conrad, S. G., 1958, Explanatory text for geologic map of North Carolina: North Carolina Dept. Conserv. Devel., Div. Mineral Resources, Bull. 71, p. 3—51. 6? TIDAL FLUCTUATIONS OF WATER LEVELS IN WELLS IN CRYSTALLINE ROCKS IN NORTH GEORGIA By J. W. STEWART, Atlanta, Ga. Work done in cooperation with the U. S. Atomic Energy Commission and the U. S. Air Force The semidiurnal water-level fluctuations of a tidal period were observed in wells in metamorphic crystalline rocks during a geologic and hydrologic study at the Georgia Nuclear Laboratory in Dawson County, Ga. The laboratory is about 45 miles north- northeast of Atlanta, at lat 34°25’N. and long 84°8’W., out 240 miles west of the Atlantic Ocean and 300 miles north of the Gulf of Mexico. This is believed to be the first reported occurrence of tidal fluctuations in wells drilled in metamorphic rocks. The Georgia Nuclear Laboratory site is underlain by metamorphic crystalline rocks and by a mantle of B—108 GEOLOGICAL SURVEY RESEARCH 1961 First quarter 8W moon Last quarter Full moon First quarter NOOW A0 SBDV °°. .—c in flffl/f/ /§////}////?//7/////fl//////// 8|9llol11l12131415 / ::- //////////////////////W/ 7 6 54; x ”////// i//// /////§S~7//////////// x >< >1 I l m _ 5-0 \§ § ,_ /°.c l ///- m»////// ////é7///// th l wllTW6\ I a; _ E a) > O E _ n a) a I 16171819120'21‘22 23 24l25T26127128 29 30|112|3|4|5 aanssaud OIHLEWOHVS NI 11VjN|VH ///// / ./ //////W/// -°°. 200 > 300 —400 FIGURE 53.2.—Stratigraphic sections showing relations be- tween lower member of Mural limestone and Lowell formation of Stoyanow (1949). Ninety One Hills section modified from Stoyanow (1949, p. 6-10); unit numbers beside column are his. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 similarity in thickness and lithology of the sequence at the two localities is shown in figure 53.2. These findings, along with other observations made during recent fieldwork, indicate that facieschanges within and variations in thickness of Lower Cre- taceous rock units in southeastern Arizona are not as extreme as heretofore commonly believed. REFERENCES Fergusson, W. B., 1959, The Cretaceous system of south- eastern Arizona, in Arizona Geol. Soc., Southern Arizona ‘Guidebook II, April, 1959: p. 43—47. B—127 Gillerman, Elliot, 1958, Geology of the central Peloncillo Mountains, Hidalgo County, New Mexico, and Cochise County, Arizona: New Mexico Bur. Mines and Mineral Resources Bull. 57, 152 p. Gilluly, James, 1956, General geology of central Cochise County, Arizona: US. Geol. Survey Prof. Paper 281, 169 p. Ransome, F. L., 1904, The geology and ore deposits of the bisbee quadrangle, Arizona: U.S. Geol. Survey Prof. Paper 21, 168 p. Stoyanow, Alexander, 1949, Lower Cretaceous stratigraphy in southeastern Arizona: Geol. Soc. America Mem. 38, 169 p. 6? 54. ORIGIN OF CROSS-STRATA IN FLUVIAL SANDSTONE LAYERS IN THE CHINLE FORMATION (UPPER TRIASSIC) ON THE COLORADO PLATEAU By JOHN H. STEWART, Menlo Park, Calif. Cross-strata are a distinctive feature of the sand- stone layers of the Chinle formation (Upper Tri- assic) on the Colorado Plateau. Channel-filling sediments, conglomerate lenses, carbonized and silicified plant material, and'locally remains of dry- land and fresh-water animals are associated with the cross-stratified layers (Stewart and others, 1959); the combination of these features clearly indicates that the cross-stratified layers are of flu- vial origin. The descriptions given apply mainly to the cross-strata in the Shinarump and Moss Back members of the Chinle formation. Tabular planar sets of cross-strata (fig. 54.1)— units of cross-strata with flat surfaces of erosion as upper and lower boundaries (McKee and Weir, 1953)—are common in the Chinle formation, and locally, at least, are the dominant type of cross- strata in the Shinarump and Moss Back members. The sets generally range in thickness from one-half foot to 2 feet. Some sets can be traced laterally along exposures for at least 200 feet. In plan view, the cross-strata appear as laminae dipping and striking uniformly. In cross section, the cross-laminae are concave upward and become tangential downwards with the bounding surface of the set. The maximum dip of cross-strata is generally about 25°. Tabular planar cross-strata probably formed in transverse bars (fig. 54.1) similar to those described by Sundborg (1956, p. 207, 270—272) in the river Klaralven in Sweden. These bars are 0.05 to 0.5 meter high and 2 to 20 meters apart. The upstream side of the bars is flat and dips upstream at an angle of about 1°. The downward side is steep and roughly at the angle of repose. Sediment is carried up the backside of the bar and deposited on the frontside, in the manner of the foreset beds of a delta building out into a body of water. As the front of the bar is built forward by continued deposition, a tabular layer of cross-strata is left. McDowell (1960) has described the formation of cross—strata by “sand waves”—the same features that Sundborg calls transverse bars—in recent deposits of the Missis- sippi River. Trough sets of cross-strata are also common in the Chinle formation, although in the Shinarump and Moss Back members they may be less abundant than tabular planar sets. These cross-strata occur in sets that have curved surfaces of erosion as upper and lower boundaries (fig. 54.1). In plan View, the sets are narrow elongate features commonly 5 to 20 feet long and 2 to 5 feet wide, with blunt termina- tions upstream. The cross-strata, in plan view, are curved and convex upstream. In a cross section out along the length of the trough, the sets are lens shaped and average about 2 feet thick. In a section cut across the trough, the lower boundary of the set GEOLOGICAL SURVEY RESEARCH 1961 I 9 (W29 )9} ’9 92) 99 ((9 999 3% A TRANSVERSE BARS AND TABULAR PLANAR CROSS-STRATA ARCUATE BARS AND TROUGH CROSS-STRATA -FIGURE 54.1.—Tabular planar and trough cross-strata and bar types. is gently U-shaped. The maximum dip of the cross- strata is generally about 25°. Trough cross-strata are generally thought to form by scouring of a trough and later filling of the trough (McKee and others, 1953 ; McKee, 1957; Stokes, 1953). Stokes (1953) ascribes the formation of troughs to water vortices that scour the stream bottom in much the same way that a tornado picks up debris on land. Such turbulent vortices, accord- ing to Matthes (1947, p. 259), are the most powerful agents of stream scour and produce troughs on stream bottoms. Some trough sets of cross-strata may have formed by filling of troughs produced by such vortices, but another process, or a modification of the above proc- ess, is suggested here to explain the formation of many, perhaps most, of the trough cross-strata in the Chinle formation. They may have formed by the downstream migration of arcuate bars that are similar to barchan dunes in shape (fig. 54.1). Ero- sion would take place, perhaps in part by vortex action, in the area between the two arms of the crescent. In such a manner, the trough is extended downstream as the arcuate bar migrates down— stream. Formation of trough cross-strata in this way is similar to the formation of tabular planar cross-strata in transverse bars, except for the dif— SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 FIGURE 54.2.—0vertumed cross—strata in Moss Back member of Chinle formation in southeastern Utah. ferent shape of the bars ‘and the formation of troughs ahead of the bars by erosion. The suggested mode of formation adequately ex— plains the shape of the trough sets and the curvature, in plan View, of the cross-strata. In addition, tabu- lar planar and trough cross-strata commonly are associated with one another and with intermediate types, suggesting that both may be formed by con- structional deposition in bars. Finally, observations in modern streams indicate that transverse bars (“sand waves”) have a tendency to break up along strike into crescentic-shaped parts (Bucher, 1919, p. 172). Trough cross-strata, following the hypothe- sis, would form in these crescentic, or arcuate bars. Many of the cross-strata in the Chinle formation are peculiarly deformed so that the upper part of the cross-strata are drawn downstream; thus the individual laminae in cross section have the shape of a U laid on its side (fig. 54.2). This type of cross-strata is termed “overturned” cross-strata by Potter and Glass (1958). This de- formation probably is caused by a flowage of sand shortly after deposition of the cross-strata. Obser- vations in modern streams show that the top few feet of the sand bed often have the consistency of “quicksand” and that they commonly move down- stream as a “fluid” mass. This motion of the top few feet of the sand bed has been observed by B—129 a civil engineer who descended in a diving bell to the bottom of the Mississippi at a point where the depth was 65 feet and the bottom of sand. Stepping to the bed, he sank into it about 3 feet, and then thrusting his arm into the yielding mass, could feel its flowing motion to a depth of 2 feet, the velocity diminishing downward (Gilbert, 1914, p. 156). A similar motion down to 3 meters was observed on the gravel beds of the upper part of the Rhine and one of its small tribu- tary streams (Bucher, 1919, p. 169—170). This motion presumably would cause the laminae to de- form. The diminishing downward velocity could account for the observed diminishing “bending” of the strata downward. REFERENCES Bucher, W. H., 1919, On ripples and related sedimentary surface forms and their paleogeog‘raphic interpretations: Am. Jour. Sci., 4th ser., v. 4'7, p. 149—210, 241—269. Gilbert, G. K., 1914, The transportation of debris by running water: U.S. Geol. Survey Prof. Paper 86, 263 p. Matthes, G. H., 1947, Macroturbulence in natural stream flow: Am. Geophys. Union Trans, V. 28, p. 255—262. McDowell, J. P., 1960, Cross—bedding formed by sand waves in Mississippi River point-bar deposits [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1925. McKee, E. D., 1957, Flume experiments on the production of stratification and cross-stratification: Jour. Sed. Petrol- ogy, v. 27, p. 129—134. McKee, E. D., Evensen, C. G., and Grundy, W. D., 1953, Studies in sedimentology of the Shinarump conglomerate of northeastern Arizona: U.S. Atomic Energy Comm. Tech. Rept. RME—3089, 48 p., issued by U.S. Atomic Energy Comm. Tech. Inf. Serv., Oak Ridge, Tenn. McKee, E. D., and Weir, G. W., 1953, Terminology for strati‘ fication and cross-stratification in sedimentary rocks: Geol. Soc. America Bull., v. 64, p. 381—390. Potter, E. P., and Glass, H. D., 1958, Petrology and sedi- mentation of the Pennsylvanian sediments in southern Illinois—A vertical profile: Illinois State Geol. Survey Rept. Inv. 204, 60 p. Stewart, J. H., Williams, G. A., Albee, H. F., and Raup, O. B., 1959, Stratigraphy of Triassic and associated formations in part of the Colorado Plateau region, with a section on Sedimentary petrology by R. A. Cadigan: U.S. Geol. Survey Bull. 1046—Q, p. 487—576. Stokes, W. L., 1953, Primary sedimentary trend indicators as applied to ore finding in the Carrizo Mountains, Arizona and New Mexico, Part 1: Tech. Rept. for April 1, 1952 to March 31, 1953: U.S. Atomic Energy Comm. Tech. Rept. RME—3043 (pt. 1), 48 13., issued by U.S. Atomic Energy Comm. Tech. Inf. Serv., Oak Ridge, Tenn. Sundborg, Ake, 1956, The river Klaralven—a study of fluvial processes: Geografiska Annalar, v. 38, no. 2—3, p. 127—316. 'X‘ B—130 GEOLOGICAL SURVEY RESEARCH 1961 55. FOSSIL WOODS ASSOCIATED WITH URANIUM ON THE COLORADO PLATEAU By RICHARD A. SCOTT, Denver, Colo. Work done in cooperation with the US. Atomic Energy Commission Fossil woods and other organic debris commonly occur with uranium in deposits of Triassic and Jurassic age on the Colorado Plateau. The possi- bility that woods of differing systematic affinities might have different capacities for localizing uran- ium has been suggested as an explanation for the highly variable uranium content of organic matter from a single mineralized zone. Woods associated with uraniferous minerals from various deposits on the Colorado Plateau were collected and studied to evaluate this possibility. AFFINITIES OF THE WOODS A11 structurally preserved woods collected from the Colorado Plateau belong to Araucarioxylon Kraus, a form genus for fossil woods like those of the modern coniferous family Araucariaceae. All Upper Triassic woods examined belong to one species, A. am‘zontcum Knowlton (fig. 55.1 A to C). Two undescribed species of Araucarioxylon are present in Jurassic strata (Morrison formation). Lack of diversity among Plateau woods is puzz- ling, for floras of the times are known to have been varied. The Chinle flora contained members of all major groups of vascular plants except dicotyledons (Daugherty, 1941); cycadeoids and other vascular plants except dicotyledons were common in Morrison time. Spore and pollen assemblages bear out the diversity (Scott, 1960). A possible explanation for this anomaly is that uranium deposits commonly are found in channel fills and floodplain deposits, depositional environments favoring degradation. Remains of small plants became too degraded to identify. Some entire logs were affected to an ex- tent that eliminated cell-wall details necessary for identification. Coalified exteriors are present on many logs with silicified cores, indicating that de- gradation proceeded centripetally. Relatively intact wood could persist in the interiors of large logs even when smaller remains were degraded; consequently, large size of the araucarians—logs 5 feet in diameter are known—may have been a selective factor favor- ing their structural preservation. Organic trash zones commonly associated with ore bodies on the Colorado Plateau probably were derived from various plants. LACK OF RELATION BETWEEN WOOD TYPE AND URANIUM Absence of marked systematic diversity among Plateau woods collected impedes direct evaluation of the possible effect of wood type upon uranium fixa- tion. Nevertheless, several observations indicate that systematic differences were not important fac- tors affecting uranium content of fossil woods. Nature of the plant remains—Variations in effec- tiveness in uranium fixation for woods of different species would derive from chemical differences among them. The organic components of wood com— prise two major groups: cell—wall components con- sisting of holocellulose and lignin make up 80 to 90 percent of the wood substance; and so-called extran- eous components consisting of resins, oils, tannins, and pigments make up the rest. Degradation of wood in nature results first in the loss of cellulosic and at least part of the extraneous components (Varossieau and Breger, 1951; Barghoorn, 1952). Later, the lignin may be altered and ultimately transformed to humic compounds. Uranium min- eralization in the sandstone-type deposits of the Plateau followed deposition of the sediments by a geologically significant time interval (Stieff, Stern, and Milkey, 1953), and unsilicified plant remains present during mineralization were composed chiefly FIGURE 55.1—Triassic wood associated with uranium. A, Araucarioxylon arizom'cum Knowlton; transverse section; x60. B, Araucarioxylon arizom’cum Knowlton; tangential section; X45. C, Araucarioxylon arizonicum Knowlton; radial section; x90. D, Wood structure in asphaltite de- rived from Araucarioxylon arizonicum Knowlton; note crushing and distortion at upper margin; the parallel lines are rays; transverse section; X45. E, Wood struc- ture in asphaltite derived from Araucarioxylon am'zon- icum Knowlton; note intrusion into silicified wood; the larger cells at lower right and scattered; X45. F, Uran- inite in Araucarioxylon arizonicum Knowlton; the white material is the uraninite seen by reflected light; it is associated with the cell wall components, probably uniting with but not replacing them; x90. B—131 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—132 of lignin residues and their derivatives. Any origi- nal compositional differences would have been mini- mized by degradational and diagenetic changes prior to mineralization. Variation in uranium content among samples of a single species—Eight samples of coalified wood from Temple Mountain, Utah, all determined as Araucarioxylon arizonicum, contained the following percentages of uranium (Roosevelt Moore, analyst) : 0.0005, 0.007, 0.007, 0.16, 0.33, 0.69, 1.3, and 5.8. Ash from each of two samples of the same species from the Adams mine on the west side of the San Rafael Swell, Utah, have uranium contents of 0.09 percent and 8.5 percent. This large range within the single species demonstrates that factors in the depositional environment at the time of mineraliza- tion, other than the afiinities of the plant material, effected marked variation in uranium concentra- tion. Association of uranium with organic matter from diverse plant sources—Uranium has been found associated with organic material from a variety of plants. For example, a sample of ash from wood of Callixylon, which has pteridophytic relationships (Beck, 1960), has been found to contain 2.58 per- cent uranium (Breger and Schopf, 1955), and ash from a lignite of Tertiary age contained 0.3 percent uranium, chiefly associated with the organic matter (Breger, Deul, and Rubenstein, 1955). Araucarian conifers are not yet known from North American Tertiary rocks; presumably the Tertiary lignite is of nonaraucarian origin. Garrels and Pommer (1959) reported that fresh spruce wood and Ter- tiary lignite were equally effective in reducing uranium to uraninite, a mineral commonly found (along with coflinite) in ores associated with coali- fied wood and other carbonaceous material (Weeks, Coleman, and Thompson, 1959). Concentration of uranyl ions by silicified dicotyledonous woods has been described by Barghoorn (written communica— tion, 1956). * Thus, various organic materials have the ability to effect fixation, and the available evidence does not suggest that systematic differences among plants that contributed organic remains were significant factors in producing ore. TEMPLE MOUNTAIN ASPHALTITE WITH WOOD STRUCTURE There is disagreement as to whether the so-called uraniferous “asphaltite” at Temple Mountain, Utah, GEOLOGICAL SURVEY RESEARCH 1961 was derived from petroliferous (Kelley and Kerr, 1958) or plant (Breger and Deul, 1959) sources. Some sections of silicified wood include regions of black, apparently amorphous, asphaltite. When ground sufl‘iciently thin, remnants of original wood structure are visible in these asphaltites (fig. 55.1, D and E). Cellular structure is present even in some asphaltite that had been forced by pressure in a plastic state into fractures in silicified wood (fig. 55.1, E). This evidence indicates that at least some of the Temple Mountain asphaltites were de- rived from wood. REFERENCES Barghoorn, E. S., 1952, Degradation of plant tissues in organic sediments: Jour. Sed. Petrology, v. 22, p. 34—41. Beck, C. B., 1960, The identity of Archeopteris and Callixylon: Brittonia, v. 12, p. 351—368. Breger, I. A., and Deul, Maurice, 1959, Association of uranium with carbonaceous materials, with special reference to the Temple Mountain region in Garrels, R. M. and Larsen, E. S. 3d, Geochemistry and mineralogy of the Colorado Plateau uranium ores: U.S. Geol. Survey Prof. Paper 320, p. 139—149. Breger, I. A., Deul, Maurice, and Rubenstein, Samuel, 1955, Geochemistry and mineralogy of a uraniferous lignite: Econ. Geology, v. 50, p. 206—226. Breger, I. A., and Schopf, J. M., 1955, Germanium and uran- ium in coalified wood from Upper Devonian black shale: Geochim. et Cosmochim. Acta, v. 7, p. 287—293. Daugherty, L. H., 1941, The Upper Triassic flora of Arizona: Carnegie Inst. Washington Pub. 526, 108 p. Garrells, R. M., and Pommer, A. M., 1959, Some quantitative aspects of the oxidation and reduction of the ores in Gar- rels, R. M. and Larsen, E. S., 3d, Geochemistry and mineralogy of the Colorado Plateau uranium ores: U.S. Geol. Survey Prof. Paper 820, p. 157—164. Kelley, D. R., and Kerr, P. F., 1958, Urano-organic ore at Temple Mountain, Utah: Geol. Soc. America Bull., v. 69, p. 701—756. Scott, R. A. 1960, Pollen of Ephedra from the Chinle forma- tion (Upper Triassic) and the genus Equisetosporites: Micropaleontology, v. 6, p. 271—276. Stieff, L. R., Stern, T. W., and Milkey, R. G., 1953, A prelim- inary determination of the age of some uranium ores of the Colorado Plateaus by the lead-uranium method: U.S. Geol. Survey Circ. 271. Varossieau, W. W., and Breger, I. A., 1952, Chemical studies on ancient buried wood and the origin of humus: Estrait du Compte Rendu: 3ieme Cong. Stratig. et de Geol. du Carbonifere-Heerlen. Weeks, A. D., Coleman, R. G., and Thompson, M. E., 1959, Summary of the ore mineralogy in Garrels, R. M. and Larsen, E. S., 3d, Geochemistry and mineralogy of the Colorado Plateau uranium ores: U.S. Geol. Survey Prof. Paper 320, p. 65—79. ’S?‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 3—133 56. LATE CENOZOIC EVENTS OF THE LEADVILLE DISTRICT AND UPPER ARKANSAS VALLEY, COLORADO By OGDEN TWETO, Denver, Colo. In the upper Arkansas Valley, 0010., unconsoli- dated deposits of Pliocene and younger age form a thick cover over the bedrock (fig. 56.1). In the Lead- ville mining district, the nature and extent of these deposits and, especially, the topography of the buried bedrock surface, are of direct concern to the mining industry. Studies there have shown that the bedrock surface is very irregular, as it is fur- rowed by deep canyons and displaced by faults younger than some of the covering materials. This rough bedrock topography markedly affects the dis- tribution of geologic formations and ore deposits, and also affected the pattern of oxidation of the ores. Erosional, depositional, and tectonic events that led to formation of this rough surface and its cover are illustrated in figure 56.2, and the two principal unconsolidated deposits are described briefly below. Subsurface data indicate that the bedrock floor of the Arkansas Valley has a relief of more than 1,000 feet. Although older materials may fill the deeper depressions, insofar as known the floor is overlain by massive brown sandy silt and inter- bedded gravel, sand, and minor volcanic ash of Plio- cene age. These deposits, the “lake beds” of earlier reports (Emmons, 1886, p. 72; Emmons, Irving, and Loughlin, 1927, p. 17), are here given the name Dry Union formation, for Dry Union Gulch, 5 miles south of Leadville. A landslide scarp near the mouth of this gulch (sec. 23, T. 10 S., R. 80 W.) exposes about 260 feet of strata in the upper part of the formation. Thickness of the formation in the Arkansas Valley ranges widely, as the top is irregu- larly eroded and the surface beneath the base has high relief. Maximum thickness of about 800 feet is known from surface distribution and exploratory openings in the Leadville area, but geophysical data' suggest that locally the formation may be as much as 2,000 feet thick. The formation probably undere lies most of the Arkansas Valley from Leadville to Salida and also occurs farther downstream near Howard (fig. 56.1), as noted by Powers (1935, p. 189). The formation is covered by younger deposits in many places but is widespread at the surface in the Salida area, Where about 500 feet of it is exposed (Van Alstine and Lewis, 1960). The detrital sediments that compose the Dry Union formation in the Leadville area are chiefly silt, sand, and gravel deposited in alluvial fans. F"_"_"—"_"'! X Tennessee : ODENVER i I = i A | ' C 0 L 0 R A D O: L-_______.._.J 1) 'y 1 O 6‘ 39° 'uenaVista> V_-oward 106° 0 10 20 MILES I 4 I I FIGURE 56.1.—Distribution of unconsolidated deposits, upper Arkansas Valley. Major deposits indicated by pattern. 3—134 GEOLOGICAL SURVEY RESEARCH 1961 Valley axis EXPLANATION Malta gravel Deposits of glacial episode 1 Pleistocene O U AT E R N A R Y Pliocene O O i TERTIARY Dry Union formation mm EXPLANATION Bedrock surface ‘ . Fault Pediment Deposits of glacial episode 3 Deposits of glacial episode 2 w _ — m”— _ _.. Valley floor during episode 3 Valley floor during episode 2 Surface of prepediment materials FIGURE 56.2.—Sketches showing effects of Late Cenozoic events. Not drawn to scale. A, diagrammatic cross section showing relations at pediment stage. B, diagrammatic cross section showing relations of deposits and valley floors of glacial epi- sodes 2, 3, and 4. C, map showing distribution of terminal moraines of glacial episodes 4 through 9 in a typical valley. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 They are characteristically ill-sorted and occur either in lenses or in thick beds (5 to 30 feet thick) that show little or no internal stratification. Chan- nel structures are numerous. Pebbles and cobbles— some of them wind polished and many of them angular—are scattered throughout the formation but are most abundant near the mountain slopes. The sediments consist chiefly of angular grains of relatively fresh rock derived from adjoining moun- tain slopes. Leached zones and caliche-cemented zones probably formed during episodes of subaerial weathering while the sediments accumulated. The Dry Union formation appears to have been derived from mountains somewhat lower than those of today, in an arid and possibly cold climate. No plant or animal fossils have been found in the for- mation in the Leadville area, except for a few poorly dated vertebrate remains in one mine (Emmons, Irving, and Loughlin, 1927, p. 19). Vertebrate re- mains found in the Salida area indicate an early Pliocene age (Van Alstine and Lewis, 1960). During the later Pliocene, the Dry Union forma- tion was stripped from some areas and dissected to depths of at least a few hundred feet in others. Ice- cap glaciation, the first of nine glacial episodes recog- nized in the region, then occurred, probably in the early Pleistocene. Following this glaciation the glacial deposits were deeply weathered, and tribu- tary valleys of the Arkansas were enlarged and deepened in the glacial drift, Dry Union formation, and bedrock. These valleys had reached depths of a few hundred feet and widths of as much as a mile when a climatic change or tectonic movement caused the streams to deposit coarse gravel, which eventu- ally filled the valleys completely. This gravel, the “high terrace gravel” of earlier reports (Emmons, Irving, and Loughlin, 1927, p. 15) is here named the Malta gravel for the railroad station of Malta, 3 miles southwest of Leadville. As seen in a cut 60 feet high at this station and also in many other places along the upper Arkansas Val- ley, the Malta gravel is buff, massive, coarse, and dirty. It shows little stratification except that im- parted by the shingled arrangement of cobbles and by a few small lenses of sand or silt. The gravel is a mixture of materials of all sizes from silt to small boulders, but rounded cobbles 4 to 10 inches in diameter predominate. Near the mountain slopes, the gravel is composed entirely of rock of local origin, but near the valley axis it is a blend of rock from various sources. No fossils have been found B-135 in it, but traces of humus occur locally. The gravel fills old valleys so its thickness varies widely; shafts and drill holes have revealed as much as 300 feet of gravel. Deposition of Malta gravel transformed dissected, hilly areas to rolling surfaces of much lower relief. During the waning. stages of gravel deposition, streams planed off the “highs” on these surfaces, producing pediments. These pediments, the “high terraces” of earlier reports (Capps, 1909; Behre, 1933; Powers, 1935), were once widespread along the upper Arkansas Valley but now exist as ero- sional remnants partly covered by glacial deposits. Since the pediments were formed, glaciation, stream erosion, and faulting have further modified the Arkansas Valley. Glacial episodes 2 and 3 oc- curred after dissection of the pediments had begun, but before the Arkansas River and its tributaries had reached their present levels (fig. 56.2 B). By the time of glacial episode 4, these valleys were at essentially their present levels. Episodes 4, 5, 6, and 7, which probably constitute the Wisconsin glacial stage, occurred in relatively rapid succession, and their glaciers were successively less extensive (fig. 56.2 C). They were followed by two minor glacial episodes, numbers 8 and 9. Faults that displace the unconsolidated deposits trend about parallel to the Arkansas Valley and are downthrown on the side nearer the valley axis. They are believed to be reactivated Laramide faults. As shown by the unconsolidated deposits and related land forms, movement occurred on the faults: (a) after deposition of the Dry Union formation; (b) after glacial episode 1; (c) late in the stage of pedi- mentation; and, possibly ((1) after the Arkansas River had reached approximately its present level. REFERENCES ‘Behre, C. H., Jr., 1933, Physiographic history of the upper Arkansas and Eagle Rivers, Colorado: Jour. Geology, v. 41, p. 785—814. Capps, S. R., 1909, Pleistocene geology of the Leadville quad- rangle, Colorado: US. Geol. Survey Bull. 386. Emmons, S. F., 1886, Geology and mining industry of Lead- ville, Colorado: U.S. Geol. Survey Mon. 12. Emmons, S. F., Irving, J. D., and Loughlin, G. F., 1927, Geology and ore deposits of the Leadville mining district, Colorado: US. Geol. Survey Prof. Paper 148. Powers, W. E., 1935, Physiographic history of the upper Arkansas Valley and the Royal Gorge, Colorado: Jour. Geology, v. 43, p. 184—199. Van Alstine, R. E., and Lewis, G. E., 1960, Pliocene sediments near Salida, Chaffee County, Colorado, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400—B, p. B245. ’R ' OCCUI‘S. B~136 GEOLOGICAL SURVEY RESEARCH 1961 57. MOVEMENT OF THE SLUMGULLION EARTHFLOW NEAR LAKE CITY, COLORADO By DWIGHT R. CRANDELL and D. J. VARNES, Denver, Colo. General relations of the Slumgullion earthflow, about 2 miles south of Lake City, Colo., have long been known (Endlich, 1876; Cross, 1909; Howe, 1909, p. 40—41; Atwood and Mather, 1932, p. 163—- 164). A brief examination of the earthflow in June 1958 revealed a stable flow about 700 years old that is being overridden by a younger flow (Crandell and Varnes, 1960). This paper presents some data on the amount and rate of movement of the younger flow during the past 20 years, and discusses the type of deformation that is occurring. Both parts of the Slumgullion earthflow head in a large cirquelike basin (fig. 57.1) about 4,500 feet in diameter, on the northeastern margin of the Lake City caldera (Burbank, 1947). The source rocks consist of hydrothermally altered latite flows and breccias of Tertiary age; abundant montmoril— lonite in the earthflows is derived from these altered rocks. The older flow is about 4 miles long and extends from the source area to a position across the valley » of Lake Fork of the Gunnison River. It descends from an altitude of about 11,400 feet to 8,800 feet at an average gradient of 650 feet per mile. The active earthflow is about 2.4 miles long and from 500 to 1,000 feet wide. It descends from an altitude of 11,400 feet to 9,700 feet at an overall gradient of about 700 feet per mile. The toe of the earthflow is steep and unstable, and both it and the body of the flow are dotted with leaning trees. The active earthflow is separated from the older earthflow by lateral cracks, along which movement The active flow also is broken by open transverse cracks in many areas, into which some of the surface drainage disappears. Velocity of the active earthflow has been studied in three ways: the displacements of trees were de— termined from air photographs made in 1939 and in succeeding years, and from measurements made on the ground; control stakes installed in 1958 were checked periodically; and an automatic time-lapse motion picture camera (Miller, Parshall, and Cran- dell, Art. 135) was installed at the flow margin to record movement between June and October 1960. Comparison of aerial photographs shows that cer- tain recognizable trees near locality C (fig. 57.1) moved 194 feet in the 13-year period 1939—52, an average velocity of 15 feet per year. Trees at a point about 3,000 feet from the head moved at an average rate of 5.8 feet per year in this same period. Near locality D, the displacement of trees that could be located on aerial photographs taken in 1951 was measured directly on the ground in 1959; these measurements indicate an average velocity of 16 feet per year. Control stakes installed in 1958 moved at a rate of about 20.0 feet per year at 10- cality D, about 15.5 feet per year at locality C, 8.5 feet per year at locality B, and 2.5 feet per year at locality A. During the period 1940—52 the toe ad- vanced an estimated distance of 30 feet, also an average rate of 2.5 feet per year. The time-lapse motion picture camera study of the active earthflow at locality D during the sum- mer of 1960 recorded a constant velocity of 0.04 feet per day. We think that the virtually constant velocity from year to year and from season to season at a given point indicates that neither long-term nor seasonal fluctuations of temperature and precipitation have much effect on movement. Maximum lubrication and pore-water pressure probably exist in the flow at all times, and the entire flow probably would be accelerated only by the addition of a large amount of material at the head by a landslide, or an earth- quake. Control stakes were installed across the entire width of the active earthflow at locality D (fig. 57.2). Stakes in the center move at a slightly greater velocity than those along thesides. This, and the evidence of decreased velocity downslope, suggest viscous flowage, contrary to an earlier opinion (Cran- dell and Varnes, 1960) that the earthflow is moving without internal deformation. The velocity decrease below locality D suggests thickening between local- ity C and the toe, but this possibility has not yet been verified by field observation. The overall rather slow rate of movement poses the question of how the toe of the active flow got to its present position of some 12,000 feet beyond its source. The oldest tree found near the toe is a leaning dead spruce with 330 growth rings; no ap- B—137 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 mo ”2589:“ng mo .tSEanficmv .nmmnuoaosn mo £830: 58: 63$ 5 Hmnfiwammw :93» .wIfiIEOQ :mmnmgosm wadfisoiw< .X quQ an 33 cm mm @5258 .3 358393. anfiio cam mind mo «.39 $3wa spec -fiaaw .520 23 mo «9?. 8.28m 23 mo ”Sam :23 a 3:0 $3580 Bananas 330w .uwwnaoh 23 page 982 .Bowfiuwm coasmfiim mo 32> 323?! 3‘1, #5 ".55on B—138 GEOLOGICAL SURVEY RESEARCH 1961 FEET I I l I I 40 — , I EI I 2 October. 1960 l I g1 35 - I E | El June, 1960 | 30— - “I E §I//I L 25 — §| I I E e|/./I 2 20- gl ' 'E “S I September, 1959 '3 5| ms t 15— I I la”) RAP/“M I 10 — H .I I I I 5 — [r If I I I I O _ I I October, 1958 I PLAN FEETSE 60 — 50 —‘ 4O __ Older, stable 30 _ earthflow 20 —' 10— Older stable . 0 ‘ eart'hflow I Younger. actlve earthflow 0 100 | l PROFILE 200 300 FEET I g VERTICAL SCALE x 2 FIGURE 57.2.—Plan and profile of younger, active earthflow at locality D, showing differential movement of control stakes between October 1958 and October 1960. preciably larger trees were seen, either alive or dead, although trees as old as 700 years grow on the older earthflow. Probably, therefore, the younger flow originated not much more than 350 years ago. But at its present velocity, the toe would have pro- gressed only 875 feet from the source area in that length of time. Several possible reasons may account for this apparent anomaly. The flow may have come nearly to its present position in a relatively short time by rapid flowage, and then may have continued to creep slowly. The earthflow also may periodically lengthen rapidly by a wave that progresses from the head to the toe, possibly propagated by sliding of new ma- terial onto the head. Slower velocity near the head of the earthflow than at the middle between 1939 and 1952 suggests such a wavelike motion. Finally, the toe may possibly advance in quick surges follow- ing a long period of very slow movement. A surge would be encouraged by a gradually accumulated bulge in the lower part of the flow. Although the . active part of the Slumgullion earthflow might be a reactivated part of the older, stable flow, age of vegetation growing on the two parts suggests other- wise. Much of the older flow, however, probably has been incorporated in the active flow, especially near the source area. REFERENCES Atwood, W. W., and Mather, K. F., 1932, Physiography and Quaternary geology of the San Juan Mountains, Colo- rado: U.S. Geo]. Survey Prof. Paper 166, 176 p. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—139 Burbank, W. S., 1947, Lake City area, Hinsdale County, in Cross, C. W., 1909, The Slumgullion mudflow [abs]: Science, Mineral Resources of Colorado: Colorado Min. Res. Board, p. 439—443. Crandell, D. R., and Varnes, D. J., 1960, Slumgullion earth- flow and earthslide near Lake City, Colorado [abs]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1846. new ser., v. 30, p. 126—127. Endlich, F. M., 1876, Report of F. M. Endlich, in U.S. Geol. Geog. Survey of the Territories Ann. Rept. 1874. Howe, Ernest, 1909, Landslides in the San Juan Mountains, Colorado: U.S. Geol. Survey Prof. Paper 67, 58 p. 5b 58. RELATIONS OF METALS IN LITHOSOLS TO ALTERATION AND SHEARING AT RED MOUNTAIN, CLEAR CREEK COUNTY, COLORADO By P. K. THEOBALD, JR., and C. E. THOMPSON, Denver, Colo. Tungsten, molybdenum, lead, arsenic, zinc, and copper have been determined by geochemical field methods in 268 samples of lithosol (poorly developed soil) from the Red Mountain area, Clear Creek County, Colo. (fig. 58.1). These data establish dis- tinct anomalies for each of the elements and suggest two stages of mineralization. The crest of Red Mountain is underlain by a plug of argillized quartz monzonite porphyry of Tertiary age (fig. 58.2 A). Surrounding the plug is silicified, argillized, or chloritized quartz monzonite of Pre- cambrian age. Two principal sets of shear zones trend N. 5° E. and N. 700 E. and dip 85° SE. and 75° NW: respectively. Both are characterized by a large number of small discontinuous gouge zones; only a few faults are continuous enough to be shown on the map. The Urad mine, on the southeast slope of Red Mountain, has produced molybdenum (Vanderwilt, 1947, p. 225), and previous work (Theobald and Thompson, 1959) demonstrated the presence of tung- sten in the same area. To establish the distribution of these metals and to search for other potential ore metals in this intensely altered area, the lithosols on the slopes of Red Mountain and the opposing slope to the north were systematically sampled and an- alyzed. Landslide and morainal debris are abundant on the steep (30° or more) slopes, but most of these materials are easily identified and were avoided in sampling. There is no evidence for distortion of the geochemical patterns by down-slope creep. Areas of anomalously high values for tungsten and molybdenum roughly coincide and trend north— easterly (fig. 58.2 B). The tungsten background is less than 20 parts per million (ppm) and anomalous values range from 40 to 3,000 ppm. The molybdenum background is less than 4 ppm, and anomalous values range from 6 to 7,000 ppm. Maximum values for both elements are in the zone of silicification. A northeast—trending fault marks one edge of the area containing anomalous amounts of molybdenum and of the area containing more than 30 ppm of tungsten. Anomalously high concentrations of lead and ar— senic occur in nearly coextensive generally north- trending areas. The lead background is probably 25 ppm or less, but this value has been obtained in only 6 samples from the northern edge of the area sampled. Anomalous values range from 50 to 6,000 ppm. The lead anomaly (fig. 58.2 C) is exceptionally large; in nearly a square mile the lead content ex- ceeds 200 ppm and in nearly a quarter of a square 100 MILES FIGURE 58.1.——Index map of Colorado showing location of this study. B—140 Arg'illized quartz monzonite porphyry ,: "fix I!” 5. r.” m a. Argillized Quartz monzonite Chloritized Contact A. AREAS OF ALTERED ROCKS Fault Dashed where inferred Pb more than 200 parts per million Pb 4000 parts per million or more Con tact Fault Dashed where inferred C, LEAD EXPLANATION I TERTIARY PRECAMBRIAN EXPLANATION GEOLOGICAL SURVEY RESEARCH 1961 W EXPLANATION W 40 parts per million or more Mo 6 parts per million or more W and M51000 parts per million or more Contact Fault B. TUNGSTEN AND MOLYBDENUM Dashed where {nf‘erred EXPLANATION , , p pe million or more Zn 100 to 175 parts per million N Zn 75 parts per million or less Contact Fault Dashed where inferred D. ZINC FIGURE 58.2—Maps showing the distribution of major rock types and faults, areas of altered rocks, and the distribution of tungsten, molybdenum, lead, and zinc in lithosols at Red Mountain, Clear Creek County, Colo. mile it exceeds 1,000 ppm. The arsenic background (not illustrated) is 10 ppm, and anomalous values range from 20 to 120 ppm. Lead and arsenic are most abundant on the south margin of the porphyry plug and generally east of both the zone of silicifica- tion and the area containing maximum tungsten and molybdenum values. The zinc background is 100 to 150 ppm; anomalies in the area sampled (fig. 58.2 D) are both positive (200 to 2,000 ppm) and negative (75 to less than 25 ppm). The negative anomaly approximately co- ‘ incides with areas of argillized or silicified rock and with the area of maximum values for tungsten and molybdenum. The positive anomaly-forms an arc SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 immediately outside of the negative anomaly, gen- erally in the area of chloritization. High values are found in some samples from the south margin of the porphyry plug at approximately the same places as the maximum values for lead and arsenic. The pattern is unrelated to structural features. It could have been produced in large part by hypogene redis- tribution of metals inherent to the rocks, although some zinc may have been introduced with lead and arsenic. ‘ The copper pattern (not illustrated) is complex. Background is 20 to 30 ppm. A negative anomaly, 10 ppm or less, has the general configuration of the negative zinc anomaly. The negative anomaly is bisected by a north-trending group of positive anomalies, 40 to 150 ppm, that coincides with the area of highest lead values. All these anomalies have maxima lying along the south boundary of the porphyry plug. The maxima for tungsten and molybdenum, coincide with the zone'of silicification, in the area of zinc and copper lows. The maxima for lead and arsenic, and the minor zinc and copper high, lie along the edge of the porphyry east of the zone of silicification. Areas of high tungsten and molybdenum are elon- gate parallel to the northeast—trending shears and B—141 areas of high molybdenum are locally elongate parallel to north-trending shears. Areas of highest lead and arsenic values are parallel to north-trend- ing shears, but they apparently have no relation to either the northeast-trending shears or the zones of alteration. These patterns suggest that tungsten was introduced and copper and zinc were redis- tributed during or shortly following alteration and that the northeast-trending shears were open at this time. The three elements were dispersed from con- duits in the area of silicification. Introduction of molybdenum probably occurred at this time but continued into a later stage of mineralization when the principal open fractures were the north-trending shears. The northeast-trending shears and the con- duit for metals introduced in the early period of mineralization were effectively closed before lead, arsenic, and some zinc and copper were distributed along thevnorth-trending shears from conduits on the southeast margin of the porphyry plug. REFERENCES Theobald, P. K., Jr., and Thompson, C. E., 1959, Geochemical prospecting with heavy mineral concentrates used to locate a tungsten deposit: U.S. Geol. Survey Circ. 411. Vanderwilt, J. W., 1947, Mineral resources of Colorado: State of Colorado Mineral Resources Board. 6? ‘z 59. HYDROLOGY OF SMALL GRAZED AND UNGRAZED DRAINAGE BASINS, BADGER WASH AREA, WESTERN COLORADO By GREGG C. LUSBY, Denver, Colo. Work done in cooperation. with Forest Service, Fish and Wildlife Service 7 Bureau of Land Management, and Bureau of Reclamation. Erosion and runoff on much rangeland in the Western States have greatly damaged manmade structures, and also caused the loss of great quan- tities of soil and hence decreased the productivity of the land. A need for quantitative data on the effectiveness of treatment-practices on rangelands has long been recognized, particularly for the Colorado Plateau in western Colorado and eastern Utah where the soils on thousands of square miles of land are held- in place by only a sparse vegetation cover. In 1953 a project was begun at Badger Wash to compare and evaluate changes in runoff and sediment yield from paired grazed and ungrazed drainage basins and to determine sources of sediment in the drain- age basins. The Badger Wash basin is in western Colorado in an area of intricately dissected terrain along the base of the Book Cliffs a few miles east of the Utah- Colorado boundary and about 25 miles west of B—142 GEOLOGICAL SURVEY RESEARCH 1961 TABLE 1.—Precipz’tation and runofi at Badger Wash, 1951,4959 {A, grazed basin; B, ungrazed basin] Precipitation and runoff (inches) Drainage Drainage basin area 1954 1955 1956 1957 1958 1959 (sqiiaige ‘ ‘__ ____g___ I as n l Precipitation Runoff Precipitation Runoff Precipitation Runoff Precipitation Runoff Precipitation Runoff Precipitation Runo 11‘ 1A....... 0066 4.97 1.08 3.24 1.06 2.12 0 8.03 1.15 2.95 0 4.31 0.4-1 113....... .084 4 68 .95 3.10 .82 1.94 0 7.58 1.29 2.95 0 4.46 .20 2A....... .167 504 1.11 3.82 1.21 1.90 .02 8.17 1.35 2 7-1: .01 4.31 .57 213....... .158 4.80 1.07 3.64 .96 2.09 0 7.81 .68 2.69 0 4.38 .39 33.4....... .059 4 76 .90 3.71 1.06 1.90 .02 7.02 2.34 {.69 0 4.31 .72 313....... .048 4 79 .84 3.48 1.06 1.82 .02 7.18 1.81 2.71 0 4.43 .30 4.4....... .022 461 .91 3.49 1.29 2.28 .03 7.48 1.29 2.4-1 .03 3.90 .60 4B....... .019 460 79 3.50 .91 2.29 0 7.88 .98 2.54 0 3.94 .29 Grand Junction. Badger Wash is a tributary of West Salt Wash, which in turn is a tributary of the Colorado River. The Badger Wash basin is under- lain entirely by the Mancos shale of Late Cretaceous age, but the lithology of the bedrock differs some- what in various parts of the basin. Shale in the west and north parts of the basin contains several thin flat-lying sandstone layers. The sandstone re- sists erosion and locally forms areas of low relief with sandy soils. On the southeast side of the basin sandstone is absent. Throughout the basin relatively steep slopes merge at their bases with gentle collu- vial slopes. Stream channels are everywhere incised into the bedrock. Eight small drainage basins, ranging in size from 12 to 107 acres, were studied. The basins were matched in four pairs so that the basins in each pair were nearly similar in drainage area, topo- graphic characteristic, soil type, and vegetation. One basin of each pair was fenced to prevent grazing, and the other received normal grazing for the area. Runoff and sediment yield from each drainage basin was measured in a reservoir at the lower end of the basin. Nine recording rain gages were installed so that at least two gages were located in each pair of basins. Point rainfall, measured at the gages, was adjusted to areal rainfall on the watersheds by the Thiessen polygon method. Precipitation and runoff at each of the eight drainage basins for the period 1954—59 are shown in table 1. The precipitation and runoff were meas- ured from about April 1 to October 31 each year. Precipitation during the winter months occurs mostly as snow and does not produce appreciable runoff. Table 1 shows a decrease in runoff from ungrazed areas as compared to grazed areas. The average runoff was 6 percent less for the ungrazed areas than for the grazed areas in 1954, and it was 51 percent less for ungrazed areas than for the grazed areas in 1959. Table 2 shows sediment yield at the four pairs of watersheds during the period 1954—59. A reduction in sediment yield from ungrazed areas is indicated by these data. Channel cross-sections were meas- ured at 49 places and line transects were measured at 8 places to determine the main areas of erosion. No change in ground level could be detected along the 8 transects, but channels at 75 percent of the cross~sections measured had increased in cross—sec- tional area during the period 1954—58, including channels in both grazed and ungrazed basins. The increase in size of channel consisted in most cases of an increase in both width and depth. Cross sec- tions at two places are shown in figure 59.1. Weather Bureau precipitation records for Fruita, Colo., about 16 miles southeast of Badger Wash, show that rainfall in the area was below normal in 5 of the 6 years between 1954 and 1959. The largest storm during the period occurred in July 1955. About 1.25 inches of rain fell in 30 minutes and produced runoffs of 0.74 to 1.02 inches at rates ap~ proaching 1,900 cubic feet per second per square mile. Storms of about this intensity occur at about 10-year intervals. TABLE 2.—Sediment yield at Badger Wash, 1954-1959 [A, grazed basin; B, ungrazed basin] Sediment yield (acrc-feet per square mile) Drainage basin April 1954— July 19554 Nov. 1956— Oct. 1957— Nov. 1958~ July 1955 Nov. 1956 Oct. 1957 Nov. 1958 Oct. 1959 10.8 0 3.80 0 1.48 7.41 0 0 0 .06 14.1 0 2.46 0 1.98 15.3 0 .70 0 2.13 12.5 0 1.70 0 3.71 8.37 0 .82 0 2.88 20.4 0 9.55 0 2.82 14.7 0 4.21 0 2.68 13.5 0 3.09 0 2.89 12.0 0 .74 0 1.72 1 Average, all grazed areas. 2 Average, all ungrazed areas. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—143 80— '— Lu LLI LI. E i Erosion 9 r— ‘ < \ Lu Deposition l I I I 5 10 15 20 DISTANCE FROM INITIAL POINT, IN FEET 42F ELEVATION, IN FEET J 5 10 15 20 DISTANCE FROM INITIAL POINT, IN FEET FIGURE 59.1.—Cross sections of gullies showing changes in channels between 1954 and 1958 at Badger Wash, Mesa County, Colo. ’X B—144 GEOLOGICAL SURVEY RESEARCH 1961 60. ABANDONMENT OF UNAWEEP CANYON, MESA COUNTY, COLORADO, BY CAPTURE OF THE COLORADO AND GUNNISON RIVERS By S. W. LOHMAN, Denver, Colo. Work done in cooperation with the Colorado Water Conservation Board Unaweep Canyon is a spectacular gorge cut to a depth of 1,500 to 3,300 feet across the Uncompahgre Plateau between the towns of Whitewater and Gate- way, Colo. (fig. 60.1 D). The nearly vertical-walled inner gorge, 500 to 1,200 feet deep, was cut in hard Precambrian crystalline rocks. The more gently sloping upper walls of the canyon were cut in softer Mesozoic sedimentary rocks. The canyon is occu- pied by two small streams, one of which flows north- eastward (East Creek) and the other southwestward (West Creek) from a gentle divide in the bottom of the gorge about 11 miles east of the crest of the plateau (fig. 60.1 D). The divide now stands about 2,500 feet above Grand Junction and Gateway. That such an immense canyon could not have been cut by such small streams flowing in opposite direc- tions was recognized as early as 1875 by members of the Hayden Survey, who attributed the cutting to the Gunnison River (Peale, 1877, p. 58, 59) or the Grand [Colorado] River (Gannett, 1882, p. 785). They believed that the canyon was abandoned solely because of renewed uplift of the Uncompahgre Plateau [arch], however, and did not recognize the more obvious possibility—stream capture. Stokes (1948, p. 39) correctly attributed the abandonment to stream capture, but did not tell the complete story which, I believe, involved two successive major stream captures, later renewed uplift of the Un- compahgre arch, and one later minor stream cap- ture. Only the highlights of these events can be given in this brief account—the details are given in a report now in preparation. The courses of the ancestral Colorado and Gunni- son Rivers probably were established by superpo- sition on widespread lava flows of post-Green River age (Hunt, 1956, p. 67 and 68) remnants of which still cap several high plateaus, including Grand Mesa. During subsequent epeirogenic uplifts and some renewed differential uplift of the Uncom- pahgre arch probably as late as Pliocene time, the streams cut downward without regard to underlying structures such as the Uncompahgre arch—a north— westward plunging faulted anticline that had been formed in part by gentle warping at about the close of the Cretaceous but mainly by more vigorous de— formation in post-Green River time. Figure 60.1 A shows my concept of what the major drainage and topographic features may have been in Pliocene time just prior to capture of the ancestral Colorado River. The soft Mancos shale (Upper Cretaceous) had been partly stripped from the hard core of the Uncompahgre arch into which the ancestral Colorado River had cut, and the ancestral Book Cliffs capped by the resistant Mesaverde group (Upper Creta- ceous) were much closer to the arch than they are now. The ancestral Colorado and Gunnison Rivers were baseleveled on the hard Precambrian rocks in Unaweep Canyon, which retarded downcutting in and upstream from the canyon for a long period of time. The subsequent tributary shown at the left (fig. 60.1 A), however, though carrying much less water than the master stream, had only the soft Mancos shale to cut, so was able to erode headward rapidly around the plunging arch. Hunt (1956, p. 68) suggested that this tributary was established by superposition on deposits at least as old as the Browns Park formation. If such deposits once were present, however, they have since been removed by erosion. Normal headward erosion in soft rock while the master stream was baseleveled on hard rock seems a more likely mode of origin of the tributary. ‘ CAPTURE OF ANCESTRAL COLORADO RIVER The subsequent tributary continued to cut head- ward until only a low divide of shale separated it from the ancestral Colorado River (fig. 60.1 A). Then, probably during some large flood in Pliocene time, the ancestral Colorado breached its banks and spilled over into the headwaters of the tributary. With the aid of this greatly increased supply of water, the tributary cut down rapidly into the soft Mancos shale, captured the ancestral Colorado, and isolated the ancestral Gunnison River (fig. 60.1 B). Soon after this capture, another tributary was cut- ting southward in the soft shale and was about to capture the ancestral Gunnison. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—145 1 io mien :8 :i‘é < 2 3:8 Rio !0 D A - o | o 1 Mesaverde group i /‘.:n ”Mugook Mesaverde group ‘n w, , , I I ’1‘ ’1 ~ 'N ‘ m 0 Z '0 C N L (9 ’~ ‘8 / ,H , 5 -m 2 ‘1‘ :0 ,0 -0 ,2 ‘C 3 I< ,4. , c " // /// ’I be}. 00,, 10 M | L ES / / x // 4/ Mesaverde group Mesaverde group N”, , 1/: \\I'/ I"— l\IA\\ I"“"ll“\\ 3/, um‘“k [I‘H’lllll‘ 3/ g , \ ; +\\\‘\n.m\ 8 00/ +\\\“”"“\ 8 [00 00“: :1: E: //, , 090)? 00““ :1: < o <2: // s 0 \\ <1 D: m“ 4 O // \\\ E-‘ O \\ [- , \\\\ 3‘ D "1 Sh a ‘ D '4 ; O ale 2/ Q _~ 00‘ \ y l r H / La 3,“ m \x‘ Jgrlcatlgn Palisade ‘ DU€19 0 a no 3 o z \ esaIN \\ ESQIN \\\\\““ “u:-tuul’ufiélum‘we Creek 'm‘ w.- \x n . "~u,.\‘(‘;an‘J° Precambrian Ancestral ’/ | \ ‘ West Creek 9‘ //I : 9 West Creek 9 "mks . 06 // ’2‘ I,’ l 0/ 6 I, l O, C l o 5 10 MILES 04,, o 5 10 MILES FIGURE 60.1.——Sketch maps of a part of western Colorado and eastern Utah, showing probable drainage pattern and topographic features at four successive stages of development. Solid drainage lines taken from Moab and Grand Junction, Utah-Colo- rado topographic maps by the Army Map Service; dashed drainage lines are hypothetical. A, just prior to capture of ancestral Colorado River; B, after capture of ancestral Colorado River and just prior to capture of ancestral Gunnison River; C, after capture of ancestral Gunnison River; and D, present drainage pattern, after renewed uplift of the Un- compahgre arch and capture of East Creek. B-146 CAPTURE OF ANCESTRAL GUNNISON RIVER Figure 60.1 C depicts my concept of what the drainage pattern and topographic features may have been sometime after capture of the ancestral Gunnison River. The divide between ancestral East and West Creeks had migrated from a point near the ancestral Gunnison River to the northeastern end of Unaweep Canyon, and was still migrating slowly southwestward. Meanwhile, a short tributary of ancestral North East Creek was cutting south- ward toward ancestral East Creek. Evidence that Unaweep Canyon was occupied by the ancestral rivers was provided when basalt peb- bles were found in high terrace gravels along West Creek about 41/2 miles above Gateway (F. W. Cater, U.S. Geological Survey, written communication, Dec. 1960). Basalt pebbles have not been found in gravels of the Dolores River (fig. 60.1 D), but are abundant along both the Colorado and Gunnison Rivers east of the arch. Cater believed it likely that the basalt pebbles found near Gateway were re- worked by ancestral West Creek from deposits laid down earlier in Unaweep Canyon by the ancestral Colorado River. RENEWED UPLIFT OF THE UNCOMPAHGRE ARCH There is evidence that the renewed uplift of the Uncompahgre arch that may have begun in Plio- cene time before abandonment of Unaweep Canyon probably continued in latest Pliocene or earliest Pleistocene time after abandonment, when uplift and crustal warping were renewed in the nearby San Juan Mountains (Atwood and Mather, 1932, p. 25—27). This renewed uplift, which is discussed in more detail in a report now ir preparation, had a profound effect upon the subsequent erosional de- velopment in and above the Grand Junction area (fig. 60.1 D), but seemingly was not the cause of any of the stream captures. CAPTURE OF EAST CREEK There is evidence that ancestral East Creek for- merly joined the ancestral Gunnison River along the course shown in figure 60.1 C, through what is now known as Cactus Park (fig. 60.1 D), but that later, in the Pleistocene, East Creek was captured by a tributary of North East Creek to form the present drainage pattern. A gentle divide in Cactus Park now separates small tributaries of East Creek and GEOLOGICAL SURVEY RESEARCH 1961 the Gunnison River. Near the northwest end of Cactus Park about 200 feet above the new channel of East Creek just 0.6 mile to the west, is a small patch of terrace deposits containing cobbles and pebbles of basalt, quartzite, and crystalline rocks. These deposits are about 800 feet below the divide in Unaweep Canyon, so probably were not deposited by the ancestral Colorado or Gunnison Rivers. At least the basalt and probably also some of the other rock types were brought into Unaweep Canyon by these rivers, and then probably were carried back to the northeast by ancestral East Creek. POSSIBLE FUTURE STREAM CAPTURES The Colorado River has cut about 15 feet into hard Precambrian rocks at two places in Ruby Canyon just east of the Utah State line, and the Gunnison River has reached Precambrian rocks at the mouth of Dominguez Creek (fig. 60.1 D). Thus once again downcutting by the two rivers is being retarded by hard rock. When Ruby and Westwater Canyons have developed deep inner gorges in hard crystalline rocks, and the Book Cliffs and adjacent belt of Mancos shale have retreated farther to the north, these canyons may be abandoned through capture of the Colorado River by a subsequent tribu- tary cutting in the Mancos shale around the Un- compahgre arch. Similarly, when a deep gorge in Precambrian rocks has been cut by the Gunnison, ’ tributaries of Indian Creek or Kannah Creek could cut headward around the gorge and capture this reach of the Gunnison River. However, other pos- sible future events, such as renewed uplift or pro- nounced climatic changes, could alter or prevent such changes. REFERENCES Atwood, W. W., and Mather, K. F., 1932, Physiography and Quaternary geology of the San Juan Mountains, Colorado: U.S. Geol. Survey Prof. Paper 166, 34 pl., 25 figs, 176 p. Gannett, Henry, 1882, The Unaweep Canyon [0010.]: Pop. Sci. Monthly, v. 20, p. 781—786. Hunt, C. B., 1956, Cenozoic geology of the Colorado Plateau: U.S. Geol. Survey Prof. Paper 279, 86 figs, 99 p. Peale, A. C., 1877, Geological report on the Grand River district: U.S. Geol. Geog. Survey Terr. (Hayden), Ann. Rept. 9, p. 31—102, maps. Stokes, W. L., 1948, Geology of the Utah-Colorado salt dome region, with emphasis on Gypsum Valley, Colorado, in Utah Geol. Soc. Guidebook to the geology of Utah, no. 3: 11 figs, 50 p. 'X‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—147 61. TRIPARTITION OF THE WASATCH FORMATION NEAR DE BEQUE IN NORTHWESTERN COLORADO By JOHN R. DONNELL, Denver, Colo. The Wasatch formation thins from 5,500 feet near the eastern margin of the Piceance Creek basin in northwestern Colorado to a featheredge along the western margin of the basin. Through most of the Piceance Creek basin the Wasatch is a monotonous sequence of brightly colored claystone beds, a few massive lenticular arkosic sandstone beds, and a few thin limestone beds; and no attempt has been made heretofore to map separate units. Within an area of several hundred square miles in Garfield and Mesa Counties the Wasatch forma— tion can be subdivided into three mappable members (fig. 61.1). The upper and lower members are mainly claystone similar to the undifferentiated Wasatch elsewhere. The middle member is mainly sandstone that forms steep ledges, in marked contrast to bad- lands topography formed by the upper and lower members. The upper member of the Wasatch in a measured section north of Plateau Creek, shown on figure 61.2, is 930 feet thick. It thins to the northwest, west, , and southwest, as does the entire Wasatch forma- tion,. and thickens to the northeast, east, and south- east. The southeastward thickening is accompanied by a partly compensating thinning of the overlying Douglas Creek member of the Green River for- mation. The upper member weathers to many colors, but red predominates in the upper part. The top of the highest persistent thick band of red claystone is used to identify the contact between the Wasatch and overlying Green River formations. A single such band, greater than 10 feet thick, was traced 20 miles along the Colorado River. South and east of De Beque, red claystones appear in progressively younger beds, and along Plateau Creek just east of the area shown on figure 1, red claystones inter- tongue with and overlie rocks about 400 feet thick belonging to the Douglas Creek member of the Green River formation. The middle member of the Wasatch attains its maximum thickness of 530 feet along Plateau Creek in T. 10 S., R. 96 W. It thins to the northeast, north, northwest, and southwest and disappears in T. 8 S., R. 99 W., and Tps. 10 and 11 S., R. 97 W. East and south of the exposures on Plateau Creek the middle member of the Wasatch is known only from bore holes. Sandstone beds of the middle member are easy to discern on electrical logs of wells along Plateau Creek for a distance of 8 miles east of the area shown on figure 61.1. Farther east some sand- stone beds are indicated on electrical logs at about the interval of the middle member, but these beds are thin and widely separated by thick claystone beds. The source of detritus in the middle member of the Wasatch probably was southeast of the area mapped. The sandstone beds thicken and become more numerous and coarse grained to the southeast. In T. 9 S., R. 96 W. (fig. 61.2), the middle member includes several conglomerate beds that contain pebbles as much as 3 inches in diameter of quartz, quartzite, and black, red, and brown chert. The sandstone in the middle member is mostly poorly sorted and feldspathic; locally the sandstone is an arkose, which suggests a nearby source. The upper contact of the middle member rises in section to the northwest; the lower contact is the base of the lowest persistent sandstone, and (unlike the upper contact) it is at about the same strati- graphic horizon everywhere in the area. The lower member of the Wasatch formation is about 650 feet thick in the measured section, figure ~assay R 95 w R 97w. R 96W. R 95w 7.": 7 “Kg 5, w M Was “a 1/ T' i\ ,1 7. 8““ / GARFIELD COUNTY :7 —as as ———— V as. ““52! r f l , . (/f \l‘ \ l p t a w EXPLANATION S, V K l l Middle member of the Wasatch formation l l l plateau . / / TixP/J \ m v0 5 i , / "\s ,7 \. Measured section O 5 10 l l K i I l 1 FIGURE 61.1.—Areal distribution of the middle member of the Wasatch formation. See figure 61.2 for measured section. 15 MILES B—148 GEOLOGICAL SURVEY RESEARCH 1961 EXPLANATION .__—l Claystone Sandstone .9. .0 _ . D - 51¢. Conglomerate Covered FEET C 300- 5 .D E 0 E 3 D. D. 3 600-— C .9 13' E 3 900— a? .D E Q) E 2 ._-. I 3 1200—1. U ._ _ . g 2 II) N S 1500—< B .D E Q) E (T) 3 O .—l 1800—— Ohio Creek conglomerate 2100 FIGURE 61.2.—Generalized stratigraphic section of the Wasatch formation. 61.2. This member has a fairly constant thickness in the western part of the area, but increases in thickness eastward. The lower member is lithologi- cally similar to the upper member except that the lower member contains more and thicker carbona- ceous claystone beds. One thick carbonaceous unit is near the top of the member just east of De Beque; and another is 75 feet above the base of the member at the east end of De Beque Canyon, about 4 miles southwest of De Beque. The lower unit contains a low-grade coal bed. Several lenticular sandstone units are interbedded with brightly colored claystone in the lower 100 feet of the member, and this sandy sequence probably correlates with drab shale and sandstone beds that contain late Paleocene plants in the lower part of the Wasatch formation north and east of Rifle. Beds of undescribed thickness in the lower part of the Wasatch formation near De Beque were called the Plateau Valley beds by Patterson (1939), who re- ports that they contain Paleocene vertebrate fossils. The fossils were found in or just above the lenti- cular sandstone beds in the lower part of the lower member at two places; one is south of De Beque in T. 9 S., R. 97 W., and the other west of De Beque in T. 8 S., R. 97 W. The vertebrate-bearing Plateau Valley beds of Patterson are not sufficiently dis- tinctive to be distinguished easily from the main body of the lower member of the Wasatch formation, and they are not differentiated on the map. In the De Beque area the Wasatch formation is everywhere underlain by conglomeratic sandstone, the Ohio Creek conglomerate, which is the oldest Tertiary unit. REFERENCE Patterson, Bryan, 1939, New Pantodonta and Dinocemta from the upper Paleocene of Western Colorado: Field Mus. Nat. History Pub. 1441, Geo]. sen, v. 6,‘ no. 24, p. 351—384. '2 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—149 62. DIAMICTITE FACIES OF THE WASATCH FORMATION IN THE FOSSIL BASIN, SOUTHWESTERN WYOMING By J. I. TRACEY, JR., S. S. ORIEL, and W. W. RUBEY, Washington, D .C., Denver, 0010., and LosAngeles, Calif. Unsorted mudstone breccia forms an extensive facies of the Wasatch formation around the north- ern periphery of the Fossil basin (“Fossil syncline”) north and west of Kemmerer, Wyo. The breccia consists of mixed angular fragments of rock of Mesozoic and Paleozoic age, some of them more than 20 feet across, in a pebbly red mudstone matrix. The mudstone breccia fits the definition of the term diamictite recently proposed by Flint, Sanders, and Rodgers (1960a, b) for “terriginous sedimen- tary rocks that contain a wide range of particle sizes.” Similar or related deposits of about the same age have been noted in other parts of Wyoming by Knight (1937), Love (1939, p. 60—62), Tourtelot (1957, p. 5, 21), Keefer (1958), and Soister (1960). The rocks resemble fanglomerate described by Sharp (1948) from the Bighorn Mountains, the Ridgway and Gunnison “tillites” from Colorado (Van Houten, 1957), and many mudflows and “lahar” (volcanic mudflow) deposits, although little or no volcanic material is present. Upper Paleozoic and Mesozoic rocks of the south- ern part of the Wyoming overthrust belt form the structural framework of the Fossil basin, which contains variegated mudstone, sandstone, and con- glomerate of the Wasatch formation, and laminated limestone, marlstone, claystone, and oil shale of the Green River formation, both of Eocene age. As in other regions (Sears and Bradley, 1924; Bradley, 1926), sequences of the laminated beds of the Green River are separated by tongues of the Wasatch for- mation, showing periodic encroachment of fluvial sediments into lakes in which the Green River for- mation was deposited. The diamictite facies of the Wasatch apparently formed during most of this period of deposition, for it grades in some places into normal variegated beds of the main body of the Wasatch formation, below basal Green River strata, and in other places it spreads out over upper- most Green River strata. Diamictite overlies older rocks of the thrust belt on Dempsey Ridge1 in the Tunp Range, along the Great Basin—Colorado River Divide, and it forms large fanlike masses projecting into the Dempsey 1Localities cited here are shown on U.S. Geological Survey topographic sheets for the Sage, Kemmerer, and Cokeville quadrangles, unless otherwise noted. Basin along the east side of Dempsey Ridge, as in the NWIA sec. 15, T. 24 N., R. 118 W. These fan- like masses are large aprons of material, in part deltas, dumped into the borders of the Green (River lake, as shown in several places where as many as three tongues of limestone of the Green River for- mation pinch out westward within the diamictite; an example is in the 81/2 sec. 3, T. 23 N., R. 118 W. Thicknesses of the diamictite facies cannot be measured accurately at most localities. Maximum thicknesses probably do not exceed 500 feet. De- spite moderate ranges in thickness, the facies is re- markably continuous along strike, but thins basin- ward to an edge within one to several miles. Rock ,of the diamictite facies, more than 100 feet thick, fills remnants of channels cut in older rock across the crest of Rock Creek Ridge, 2 miles west of Dempsey Ridge. It is also found in Rock Creek valley, between exposures on Rock Creek Ridge and on Dempsey Ridge; rocks on the west are 500 to 1,000 feet lower than on Dempsey Ridge, whose western flank coincides with a normal fault. Most common boulders and blocks are from the Mesozoic Ankareh formation, Nugget sandstone, Twin Creek limestone, Preuss sandstone, and Ephraim conglomerate, and from the upper Paleo- zoic Wells and Amsden formations. Blocks of quart- zitic conglomerate from the Ephraim are especially common locally and are the coarsest; some are up to 20 feet in length. The extraordinary range in particle sizes of the deposits is striking. A complete gradation of shapes and angularity, as well as concentrations, of coarse fragments is also evident. Orientation of blocks is not evident; the deposits seem chaotic or jumbled. Gravitational sliding and solifluction seem to us the most probable explanations of origin. De- posits filling channels cut into older rocks likely originated as mudflows. Slopes forming the mar- gins of the basin in Eocene time were steep and deeply weathered, and the hillsides and drainage- ways in times of abnormal rainfall were probably choked with debris that was being moved basinward. Normal faulting since Wasatch time has greatly altered topographic relations. The nearest present outcrop of Ephraim conglomerate that might have B—150 served as a source for the material along Dempsey Ridge is 6 miles west and more than 2,000 feet lower. Other exposures of the diamictite facies are found along the northeast periphery of the Fossil basin, on the western slopes of Commissary Ridge. Large blocks of upper Paleozoic to Upper Cretaceous rocks were derived from formations that underlie the Ridge. In places they are in a pebbly red mudstone matrix, in others they lie free on a gently sloping surface and probably are relict blocks of the diamic- tite facies. Large accumulations of rubble on Boulder Ridge, north and south of Sage station in the Sage quad— rangle, may be part of the diamictite facies. The boulders and blocks come mostly from Paleozoic lime- stones exposed now in the Crawford Range some miles to the southwest. One very large block of Ordovician dolomite 2 miles north of Sage is more than 600 feet long. Others are 40 to 60 feet long. About 4 miles south-southwest of Sage, in parts of secs. 25, 35, and 26, T. 21 N., R. 120 W., a large mass of steeply dipping Cambrian, Ordovician, and Devonian limestone and dolomite, 3,800 feet long, 1,400 feet Wide, and 200 feet high, seems to be surrounded and underlain by Lower Cretaceous mudstone and sandstone. Rocks composing this mass strike nearly normal to similar Paleozoic strata ex- posed 1/2 to 3 miles northwest and southwest in the northern part of the Crawford Mountains. The mass may be a klippe of the nearby Crawford thrust plate; possibly it is merely a slid block similar in ori- gin to, though differing greatly in scale from, the rubble that makes up the bulk of the diamictite facies. A diamictite facies of the Wasatch formation has also been recognized along the western margin of the Green River basin south of LaBarge Creek in the Fort Hill quadrangle, where it was previously mapped by Schultz (1914, pl. 1) as the conglomeratic Almy formation of the Wasatch group. The facies intertongues here, also, with the Green River for- mation and is not, at least in this area, older than the main body of the Wasatch formation, as gen- erally supposed. Farther north along the western margin of the Green River Basin, a lower member of the Wasatch GEOLOGICAL SURVEY RESEARCH 1961 formation, consisting of pebbly red mudstone and some large blocks, extends almost continuously for 40 miles or more northward along the east sides of Deadline and Meridian Ridges, to Horse Creek in the Big Piney quadrangle and beyond. Throughout the region the diamictite facies may have accumu- lated soon after the major overthrust plates had moved into their present positions. In a few places, however, as in the northern part of Deadline Ridge, in the Slfiz sec. 32, T. 29 N., R. 114 W., the diamictite is involved in the thrusting. Distribution of the facies was evidently controlled by proximity to steep slopes and mountainous relief, the growth of Which need not have coincided more than generally in time and place with final movements of the thrust plates. REFERENCES Bradley, W. H., 1926, Shore phases of the Green River formation in northern Sweetwater County, Wyoming: US. Geol. Survey Prof. Paper 140—D, p. 121—131. Flint, R. F., Sanders, J. E., and Rodgers, John, 1960a, Sym- mictite: a name for nonsorted terrigenous sedimentary rocks that contain a Wide range of particle sizes: Geol. Soc. America Bull., v. 71, p. 507—510. 1960b, Diamictite, a substitute term for symmictite: Geol. Soc. America Bull., v. 71, p. 1809. Keefer, W. R., 1958, Cenozoic landslides versus klippen [abs.] : Geol. Soc. America Bull., v. 69, no. 12, pt. 2, p. 1732. Knight, S. H., 1937, Origin of the giant conglomerates of Green Mountain and Crook’s Mountain, central Wyoming [abs.]: Geol. Soc. America Proc. 1936, p. 84. Love, J. D., 1939, Geology along the southern margin of the Absaroka Range, Wyoming: Geol. Soc. America Spec. Paper 20, 134 p. Schultz, A. R., 1914, Geology and geography of a portion of Lincoln County, Wyo.: U.S. Geol. Survey Bull. 543, 141 p. Sears, J. D., and Bradley, W. H., 1924, Relations of the Wasatch and Green River formations in northwestern Colorado and southern Wyoming: US. Geol. Survey Prof. Paper 132—F, p. 93—107. Sharp, R. P., 1948, Early Tertiary fanglomerate, Big Horn Mountains, Wyoming: Jour. Geology, v. 56, no. 1, p. 1—15. Soister, P. E., 1960, Landslide debris from Cretaceous rocks in the Wind River formation of early Eocene age, Wind River basin, Wyoming [abs.]: Geol. Soc. America Bull., v. 71, no. 12, pt. 2, p. 1982—1983. Tourtelot, H. A., 1957, The geology and vertebrate paleontol- ogy of upper Eocene strata in the northeastern part of the Wind River basin, Wyoming, pt. 1, Geology: Smith- sonian Misc. Coll., v. 134, no. 4, 27 p. Van Houten, F. B., 1957, Appraisal of Ridgway and Gunnison “tillites,” southeastern Colorado: Geol. Soc. America Bull., v. 68, p. 383—388. 'X SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B~15l 63. TONGUES OF THE WASATCH AND GREEN RIVER FORMATIONS, FORT HILL AREA, WYOMING By S. S. ORIEL, Denver, Colo. Three tongues of the Green River formation and two tongues (as well as the main body) of the Wasatch formation, all of early Eocene age, have been recognized during mapping of the Fort Hill quadrangle. The Fort Hill 15-minute quadrangle lies on the western margin of the Green River basin in western Wyoming, about 15 miles north of the town of Kem- merer. The Green River and Wasatch formations crop out in eastward-dipping cuestas that extend northward through the quadrangle. These cuestas have been cut by eastward-flowing tributaries of Green River. The facies relations (fig. 63.1) be- tween the two formations are well exposed in steep bluffs along these tributaries. The lower tongues were recognized and described by Donavan 1 (1950). The main body of the Wasatch formation consists chiefly of variegated red, yellow, buff, purple, green, and gray mudstone with interbedded marlstone, sandstone, and lentils of conglomerate. The unit becomes increasingly conglomeratic westward. The Fontenelle tongue of the Green River for- mation (Donavan, 1950, p. 63—64; Bradley, 1959, p. 1072) conformably overlies the main body of the Wasatch formation. Only the basal 50 to 60 feet of strata assigned to the Fontenelle by Donavan at his type section 2 and in adjoining areas is here included in the unit. As thus restricted, the tongue consists of very thinly laminated light-gray to white muddy limestone, marlstone, calcareous very fine grained sandstone, and calcareous mudstone. A wedge of detrital rocks, about 250 feet thick in the Fort Hill quadrangle, overlies the Fontenelle tongue and is here assigned to the New Fork tongue of the Wasatch formation. The New Fork tongue consists dominantly of green and gray mudstone with numerous lenses of yellow, buff, and brown, very fine- to medium-grained sandstone. The basal 20 to 45 feet is locally thinly laminated; most of the sequence is like the Wasatch formation in coarse- ness of the mudstone bands but lacks the characteris- 1Donavan, Jack H., 1950, Intertonguing of Green River and Wasatch formations in part of Sublette and Lincoln Counties, Wyoming: M.S. Thesis, Univ. Utah. 2Donavam, Jack H., 1950. Inter-tonguing of Green River and Wasatch formations in part of Sublette and Lincoln Counties, Wyoming: M.S. thesis, Univ. Utah. Donavan’s type section, no. 7 (p. 40—41), is located erroneously in his description but is shown properly on his geologic map in the Nwlét sec. 13, T. 24 N., R. 115 W. tic shades of red and purple. These beds grade laterally westward into mudstone and sandstone beds in which red is the dominant color, as in the SW1/4SW1/4 sec. 15 and NW1/4 sec. 26, T. 26 N., R. 114 W. The New Fork tongue of the Wasatch formation is overlain by an unnamed middle tongue of the Green River formation. The middle tongue is divis- ible into two readily distinguishable and mappable units; a lower white unit composed mainly of white- weathering low-grade oil shale and white to gray limestone, and an upper buff to brown, locally pink, gray, or white limestone, marlstone, mudstone, silt- stone, and sandstone unit. Both units are very thinly laminated and both grade westward into thicker bedded organic limestone of nearshore facies (Bradley, 1926) as do the other tongues of the formation. Another wedge of detrital rocks composed mainly of green and gray mudstone and yellow to brown sandstone overlies the middle tongue of the Green River formation. This wedge, here informally desig- nated the upper tongue of the Wasatch formation, is 200 feet thick in the central part of the Fort Hill quadrangle but only 100 feet thick along its eastern margin. This eastward thinning is due to eastward tonguing with algal and ostracodal lime- stone and laminated marlstone assigned to the Green River formation. The uppermost unit of the sequence, directly be- neath the Bridger formation, is here termed the upper tongue of the Green River formation. Rocks included are thinly and evenly bedded to laminated, tan, yellow to brown, and gray limestone, marlstone, mudstone, siltstone, and sandstone, particularly os- tracodal, gastropodal, and algal limestone. Recognition of the relations between the Green River and Wasatch formations in the Fort Hill area has been hampered by the presence of the two wedges of detrital rocks that do not fit original descriptions and definitions of either of the for- mations. The name Wasatch was originally applied by Hayden (1869, p. 91) to variegated sandstone and claystone in which some shade of red predominated; the emphasis on red hues was again stressed in a later description (1870, p. 106, 113—114). The name Green River, on the other hand, was applied by B—152 W E Upper tongue Upper tongue Middle tongue Green River formation New Fork tongue Wasatch formation Fontenelle tongue ‘cZ:;__________::——_——~__‘*~——.__— Main body FIGURE 63.1.——Idealized section of Wasatch and Green River units in the Fort Hill area, Wyoming. Hayden (1869, p. 90—91) to “thinly laminated chalky shales” which locally include “combustible or petro— leum shales”; the peculiarly banded appearance of the rocks was stressed, although the abundance of limestone in the great range of compositions of the laminae was recognized. Emphasis in original descriptions, therefore, was on color for one unit and on primary structure for the other. Some subsequent usage of the terms, however, has stressed genesis. Rocks considered to be of fluvial origin were assigned to the Wasatch for- mation ; those of lacustrine origin to the Green River formation. Lack of assurance regarding the origin of the green mudstone—brown sandstone facies, however, makes adoption of this criterion im- practical. Rocks assigned here to the New Fork tongue of the Wasatch formation were included by Donavan (1950) in the Fontenelle tongue of the Green River formation in the Fort Hill area Where they consist of green, not red, mudstone and brown sandstone. Beds similar to these, on the other hand, make up the bulk of the sequence assigned to the New Fork tongue (Donavan, 1950) farther north in its type area where, however, basal strata include red, brown, and purple mudstone. Color seems to have influenced the stratigraphic assignment. Rocks in the two wedges of green mudstone and brown sandstone lack the dominant reds typical of GEOLOGICAL SURVEY RESEARCH 1961 the Wasatch formation yet do not contain the lami- nae diagnostic of the Green River formation. The absence of red is not unusual because green mud- stone and yellow to brown sandstone form narrow, intermediate facies between more typical exposures of the two formations at many places elsewhere in the Green River and Fossil basins. Moreover, an absence of red may be expected close to the ancient lake in which the Green River formation was de- posited, because of poor drainage and reducing con- ditions in contrast to the well-drained alluvial soils of higher elevations. The two wedges of detrital rock are assigned here to the New Fork and unnamed upper tongues respec- tively 0f the Wasatch formation because: 1. Although dissimilar in color, the rocks are simi- lar in every other respect (including composi- tion, primary structures, and faunal 'content) to those commonly and originally assigned to the Wasatch. 2. The rocks are similar in every respect, including color, to some that are included in the for- mation at many other localities. 3. Assignment to the Wasatch formation facili- tates recognition, through stratigraphic nomen- clature, of two significant geologic events along the western margin of the Eocene Gosiute Lake, both marked by extensive deposi- tion of detrital material advancing from the west and possibly by eastward regressions of the lake. ' REFERENCES Bradley, W. H., 1926, Shore phases of the Green River forma- tion in northern Sweetwater County, Wyoming: U.S. Geol. Survey Prof. Paper 140—D, p. 121—131. 1959, Revision of stratigraphic nomenclature of Green River formation of Wyoming: Am. Assoc. Petroleum Geologists Bull., v. 43, no. 5, p. 1072—1075. Donavan, J. H., 1950, Intertonguing of Green River and Wasatch formations in part of Sublette and Lincoln Counties, Wyoming, in Guidebook to southwest Wyoming: Wyoming Geol. Assoc. 5th Ann. Field Conf., p. 59-67. Hayden, F. V., 1869, Preliminary field report (3d arm.) of the U.S. Geol. Survey of Colorado and New Mexico, 155 p. 1870, Sun pictures of Rocky Mountain scenery, with a. description of the geographical and geological features and some account of the resources of the Great West: New York, 150 p. ’5? SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—153 64. AGE OF THE EVANSTON FORMATION, WESTERN WYOMING By W. W. RUBEY, S. S. ORIEL, and J. I. TRACEY, JR., Los Angeles, Calif, Denver, Colo., and Washington, D. C. Renewed interest has arisen concerning the age of the Evanston formation because it provides a means for dating precisely some tectonic events in the thrust belt of western Wyoming. The formation was long of interest because of its bearing on the Laramie problem and therefore on the boundary be— tween the Cretaceous and Tertiary systems (Veatch, 1907, p. 86—87; Schultz, 1914, p. 70—71). The Evanston formation was formally named by Veatch (1906, p. 332) and defined (1907, p. 76) to include strata that were earlier referred to in- formally as the “Evanston beds” and “Evanston coal series.” No type section was designated. Veatch’s criteria (1907, p. 77) for distinguishing the forma- tion from the underlying Adaville formation and from overlying strata, which he assigned to the Wasatch group, are still valid. Veatch failed to recognize the Evanston over much of its extent, however, and distinguished it (see his pl. 3) in only a few small areas near the town of Evanston. Disagreements among paleontologists regarding the age of fossils found within the Evanston for- mation led Veatch (1907, p. 84—87) to discuss the problem at length. The age, he concluded tenta- tively, was early Tertiary, but he used the symbol KTe to designate the unit on maps and cross sections. Geologists other than Schultz (1914, p. 68) have not made use of the Evanston formation as a map- pable lithologic unit. Beds north of the type area formerly assigned to the Evanston by Schultz were defined as the Hoback formation by Eardley and others (1944). Extensive exposures of the Evanston formation have been mapped by us in the Cokeville, Kemmerer, and Sage quadrangles, Lincoln County, and Big Piney quadrangle, Sublette County, Wyo. The belt of the rocks assigned by Veatch (1907, pl. 3) to his Almy formation in the eastern part of the Fossil basin belongs in the Evanston formation as well as scattered exposures well within the basin which he assigned to his Knight formation. Our assign- ment of these rocks to the Evanston is supported both by Veatch’s published description and by com- parison of certain distinctive rock types in the quad- rangles mentioned with those in exposures at the type area. Exposures of the unit in both areas are similar in gross aspect and in some details, although not identical because. of facies differences typical of continental strata. Fossils in the Evanston formation in the Kem- merer, Sage, and Cokeville quadrangles include ver— tebrates, fresh-water invertebrates, leaves, and pollen. Ages inferred from these varied fossil forms are in agreement. Vertebrates from near the base of the formation include the jaw of Triceratops cf. T. flabellatus Marsh, indicating probable Lance (:Hell Creek), latest Cretaceous age (G. E. Lewis, written com- munication, 1958), and numerous unidentifiable dino- saurian bone fragments indicative only of Mesozoic age. Mollusca from strata near but above the verte- brate horizon are different from those of Paleocene age and are regarded of probable Cretaceous or early Paleocene age (D. W. Taylor, written commu- nication, 1960). Leaves found about 50 feet above the base of the Evanston formation, about 20 miles north of the vertebrate localities, were identified by J. A. Wolfe (written communication, 1959) as Dryophyllum sub- falcatium Lesquereux, Cinnamomum lim'folium Knowlton, and Dombeyopsis obtusa Lesquereux and assigned a Lance (latest Cretaceous) age. A Collec- tion from a nearby locality yielded Protophyllocladus subintegrifolius (Lesquereux) Berry, Ficus plani- costata Lesquereux, and Cinnamomum affine Les- quereux, also of Late Cretaceous age (R. W. Brown, written communication, 1958). Fourteen species of pollen were identified from mudstone samples collected at one of the leaf locali- ties. The presence of Proteacidites annularis Cook- son, as well as other forms, indicates the samples are no younger than Late Cretaceous (E. B. Leopold, written communication, 1959). Pollen species identified in samples from mudstone close to the Triceratops locality are even more va- ried; 32 species were recognized. The species Schi- zaeoisporites pseudodorogensis Potonié, Osmwmdaci- dites wellmanm'i Couper, Proteacidites annularis Cookson, and associated forms confirm the Late Cre- taceous age of theserocks (E. B. Leopold, written communication, 1959). , . Fossils found near the middle of the Evanston formation include Paleocene, possibly middle Paleo- B—154 cene, leaves (R. W. Brown, written communication, 1958) and pollen (E. B. Leopold, written communi- cation, 1959). A varied vertebrate fauna has been reported 250 to 300 feet below the top of the unit by Gazin (1956, p. 708) who interprets the presence of Plesiadapis cf P. fodinatus Jepsen, Pheocodus sp., and other genera to indicate an early late Paleocene (Tiffany) age. N o fossils have been found in uppermost strata assigned to the formation. Additional collections of leaves and pollen from exposures in other parts of the Sage, Kemmerer, and Cokeville quadrangles confirm the Cretaceous and Paleocene age of the Evanston formation in this area. _ Cretaceous age assignments for parts of the Evanston formation in the quadrangles under study are not in accord with the Paleocene age inferred for the unit in its type area some 30 miles to the south in earlier reports (for example, Brown, 1949; Eaton, 1955, p. 116). The apparent discrepancy in age led us to re- examine exposures of the formation in its type area. The thickest section reported by Veatch (1907, p. 80) lies along the boundary between the western parts of secs. 18 and 19, T. 16 N., R. 120 W., north of the old settlement at Almy and is regarded by us as the informal reference section. Fossils were collected by us directly below and above a main coal bed north of the old No. 7 mine (Veatch, 1907, pl. 3). Leaves were examined by R. W. Brown (1958), mollusks by D. W. Taylor (1960), and pollen by E. B. Leopold (1959, 1960), who conclude they indicate a Paleocene age. No megascopic fossils were found considerably below the main coal bed. Samples of mudstone col- GEOLOGICAL SURVEY RESEARCH 1961 lected directly above and below the horizon of the lowest conglomerate layer mentioned by Veatch (1907, p. 80), however, contain an assemblage of pollen of latest Cretaceous age (E. B. Leopold, writ- ten communication, 1961). Among the more criti- cal species are Aquilapollenites quadrilobus Rouse, Appendicisporites tricornitatus Weyland and Grei- feld, and Protaacidities annularis Cookson. The pos- sibility that these forms are reworked from older rocks is considered unlikely. Collections from the type area, therefore, seem to confirm the Cretaceous and Paleocene age of the Evanston formation, to verify the age assignments made by Knowlton and Stanton some 60 years ago (Veatch, 1907, p. 86—87), and to support Veatch’s use of the map symbol KTe. REFERENCES Brown, R. W., 1949, Paleocene deposits of the Rocky Moun- tains and Plains: U.S. Geol. Survey prelim. map, scale 1:1,000,000, with descriptive notes. Eardley, A. J., and others, 1944, Hoback-Gros Ventre-Teton [Range, Wyo.], field conference: Michigan Univ. geol. map, tectonic map, with sections, 2 sheets. Eaton, E. C., 1955, Catalog of formations for Green River Basin and Adjacent areas, in Guidebook to the Green River Basin: Wyoming Geol. Assoc. 10th Ann. Field Conf., p. 114—121. Gazin, C. L., 1956, The occurrence of Paleocene mammalian remains in the Fossil basin of southwestern Wyoming: Jour. Paleontology, V. 30, no. 3, p. 707—711. Schultz, A. R., 1914, Geology and geography of a portion of Lincoln County, Wyoming: U.S. Geol. Survey Bull. 543, 141 «p. Veatch, A. C., 1906, Coal and oil in southern Uinta County, Wyoming: U.S. Geol. Survey Bull. 285—F, p. 331—353. 1907, Geography and geology of a portion of south- western Wyoming: U.S. Geol. Survey Prof. Paper 56, 178 p., 26 pl. ’5? 65. PERMAFROST AND THAW DEPRESSIONS IN A PEAT DEPOSIT IN THE BEARTOOTH MOUNTAINS, NORTHWESTERN WYOMING By WILLIAM G. PIERCE, Menlo Park, Calif. The discovery of permanently frozen ground in a peat deposit in the southeastern part of the Bear- tooth Mountains, northwestern Wyoming, is of in- terest because permafrost is of infrequent occur- rence this far south in the Rocky Mountains. Asso- ciated with it are numerous thaw ponds, which in- dicate the presence of permafrost. The Sawtooth peat deposit, named from Sawtooth SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC Mountain half a mile to the north, is in the western part of the Deep Lake quadrangle, at latitude 44°53’N. It is at an altitude of 9,700 feet, a few hundred feet below timberline in this area. The peat extends over an area 1,500 feet wide and 2,000 feet long and has an estimated thickness of 10 to 15 feet. Peat is not forming here now, but rather is being removed by erosion. The deposit lies in a broad northwest—trending valley that appears to be downfaulted on its southwest side. The shape and appearance of the valley suggest that it may be a pre-Wisconsin ice-scoured valley. The broad valley in which the peat was deposited is part of the Bear- tooth Mountains subsummit surface (peneplain of Bevan, 1925), a deeply weathered pre-Wisconsin surface developed on Precambrian granitic and gneissic rocks. During the most recent glaciation, presumably Wisconsin, deep valleys on three sides of the deposit were filled with ice that came up to about the level of the subsummit surface, but the peat deposit was not glaciated. Two shallow holes were dug in the peat 0n Au- gust 24, 1956. At a depth of 15 inches a sharp con- tact between moist peat above and a solid frozen mass of ice and peat below was found in both holes. Al- though excavation into the solidly frozen peat was continued for only a few inches, it seems probable that the ice extends downward some distance in the peat. The deposit was Visited again on July 30, 1957, and several additional holes were dug. Near the previous holes, solidly frozen peat occurred at a depth of 18 inches. A hole in the previously un- tested southern part of the deposit, which is marshy and grass-covered, also reached ice at a depth of 18 inches. Patterned ground, in the form of polygons 5 to 10 feet across, is conspicuous in places (fig. 65.1). The polygons are in the peat and consist of shallow trenches separating slightly convex areas. They may have been formed by ice-wedges in the peat. Even more striking, however, are circular undrained depressions in the central part of the peat deposit. Superficially they resemble sink holes, about 6 feet deep and from a few feet to 40 feet in diameter. Their nearly flat bottoms are covered by 2 to 3 feet of water. The peat at the margins of the depressions is slowly caving downward, as shown by marginal cracks (fig. 65.2), and by circular cracks beyond the margin. The depressions are not due to solu- tion, for neither the peat nor the underlying Pre- cambrian rocks are readily soluble. There is no evidence to indicate that they resulted from water or wind erosion. B—155 SCIENCES, ARTICLES 1-146. FIGURE 65.1.—Patterned ground in the Sawtooth peat deposit. Hammer in center for scale. The origin of the depression was discussed with D. M. Hopkins, who suggested that they are thaw depressions, formed by melting of the ice beneath. The irregular land surface produced by this process has been called thermokarst by Russian scientists and cave-in lakes are one of its surface features (Muller, 1945). Hopkins (1949) proposed the name “thaw lakes” as synonymous with cave-in lakes, and defined thaw depressions as depressions that result from subsidence following the thawing of peren- nially frozen ground. The depressions in the Saw- tooth peat seem to be clearly thaw depressions, formed by melting of ice within the peat. The de- pressions probably started forming where slight irregularities in the ground surface permitted a FIGURE 65.2.—Two thaw depressions in the Sawtooth peat deposit. The cracks in the walls of the depressions indi- cate lateral growth by downward caving of the peat. These two depressions have grown until they now coalesce. Hammer on bank in foreground for scale. B—156 little water to accumulate. The water in the de- pressions kept the underlying peat wet and per- mitted downward thawing to continue in the de- pressions during the summer months, while beyond the depressions the dry peat insulated the ice be- neath it. As the ice thawed the volume of the peat and ice lessened and the depression deepened. The peat is not older than Pleistocene. A sample of the peat, obtained from about a foot below the eroded top of the deposit was submitted for exami- nation for pollen and diatoms and for a carbon 14 age determination. K. E. Lohman found an assem- blage of diatoms (USGS diatom loc. 4209) that is no older than late Pleistocene, and he reports that the same diatom assemblage is living today in cool to cold ponds. The radiocarbon age of the sample (laboratory number W—459) is reported by Meyer Rubin as 7,570 years, :l: 400 years. The CM age thus indicates that the upper part of the peat bed is post-Wisconsin in age, but the lower part of the bed may be of late Wisconsin age. The presence of perennial ice indicates that the present climate is cold enough at the altitude and latitude of the Sawtooth peat to maintain perma- GEOLOGICAL SURVEY RESEARCH 1961 frost provided there is a few feet of exceptionally good insulating cover. The permafrost in the Saw- tooth peat has an antiquity greater than just the last few years, for the thaw depressions have been in the process of developing for some time. If the rate of retreat measured by Wallace (1948) on the margins of some cave—in lakes in eastern Alaska is applicable, then the time required to form the larger depressions may have been less than a hundred to a few hundred years. However, their growth may have been intermittent, and, if so, a longer time may be represented. REFERENCES Bevan, Arthur, 1925, Rocky Mountain peneplains northeast of Yellowstone Park: Jour. Geology, v. 33, p. 563—587. Hopkins, D. M., 1949, Thaw lakes and thaw sinks in the Imuruk Lake area, Seward Peninsula, Alaska: Jour. Geology, v. 57, p. 119—131. Muller, S. W., 1945, Permafrost or perennially frozen ground and related engineering problems: Ofiice, Chief of Engi- neers, US. Army Spec. Rept. Strategic Eng. Study 62, p. 83—84. Wallace, R. E., 1948, Cave-in lakes in the Nebesna, Chisana, and Tanana River valleys, eastern Alaska: Jour. Geology, v. 56, p. 171—181. 6% 66. EVIDENCE FOR EARLY CRETACEOUS FOLDING IN THE BLACK HILLS, WYOMING By GLEN A. IZETT, CHARLES L. PILLMORE, and WILLIAM J. MAPEL, Denver, Colo. The Lakota formation of Early Cretaceous age and its lithogenetic equivalents the Kootenai forma- tion in central Montana and the lower part of the Cloverly formation in Montana and Wyoming are fluviatile and lacustrine deposits that extend in a relatively thin sheet over several hundred thousand square miles in the Western Interior region. Re- gional stratigraphic relations indicate that over broad areas the surface on which these rocks were deposited was essentially undisturbed by folding or faulting. However, mapping of the Lakota and adjacent formations along the west side of the Black Hills has shown that in two areas, folds having amplitudes of more than 100 feet in horizontal dis- tances of 2 to 3 miles were formed in Early Cre- taceous time. Similar folds that might be concealed by unconformably overlying rocks in the adjacent Powder River basin would have interest for their oil and gas possibilities. Early Cretaceous folding is indicated by local angular unconformities within and bounding the Lakota formation at a small dome in Barlow Canyon in T. 54 N., Rs. 65 and 66 W., Crook County, Wyo., about 5 miles north of Devils Tower, and at a small dome bisected by Oil Creek in T. 47 N., R. 62 W., Weston County, Wyo., about 8 miles north of New- castle (fig. 66.1). The sequence of beds and the stratigraphic relations at the two localities are shown by figure 66.2. At Barlow Canyon, the Morrison formation and part of the Redwater shale member of the underlying Sundance formation of Late Jurassic age are trun- SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 M0NTAN£__________‘. '— —_ WYOMING | I l I a l i ' ‘ I l I o Hulett I l l Barlow Canyon area I l I CROOK . I oSundance m I ‘ ° c: ' . 2 | ' oGIllette i 2 | E: I c I CAMPBELL r———————- ——Ek U to 2 l a I l o p n o | O a I | Oil Creek area X l > I l I ° I ‘ l Newcastle W'ES'TC)N ' l I l I . ' 1 | L_.._______.____ _____ _ ._ O 10 20 MILES FIGURE 66.1.——Map showing location of Barlow Canyon and Oil Creek areas, northeastern Wyoming. cated beneath an angular unconformity that dies out laterally in the basal part of the Lakota for- mation (fig. 66.2 A). Polished pebbles and cobbles of quartzite and chert in the basal part of the Lakota formation mark the position of the unconformity. At locality 3 (fig. 66.2 A), a basal conglomerate in the Lakota contains belemnite fragments derived from the underlying Redwater shale member of the Sundance. The Lakota thickens abruptly northward between localities 2 and 3 (fig. 66.2 A) in a manner that suggests the Lakota occupies a channel where the formation is thickest; however, folding and sub- sequent truncation of the upraised rocks probably accounts for the absence of most of the missing rocks in the Morrison and Sundance formations on the crest of the fold. The amplitude of the Early B-157 Cretaceous fold at this locality is estimated to be about 125 feet, and the areal extent of the fold is about 4 square miles. Two periods of folding can be recognized along Oil Creek (fig. 66.2 B). The lower part of the Lakota formation is truncated beneath an angular uncon- formity Within the formation (locality 2), and the upper part is truncated beneath an angular uncon- formity at the base of the overlying Fall River formation (locality 3). At locality 2, the basal part of the Fall River formation contains granules and pebbles of quartzite and chert probably derived from erosion of the Lakota at the crest of the fold. The amplitude of the Early Cretaceous fold at Oil Creek is estimated to be about 200 feet, and the areal extent of the fold is about 2 square miles. The limited extent of the folds in both areas sug- gests that folding was caused by local rather than regional forces. Redistribution of evaporites in the Spearfish (Triassic and Permian) or Minnelusa (Permian and Pennsylvanian) formations, which un- derlie the Lakota formation at shallow depths, seems a possible explanation for the folding. Repeated episodes of folding such as occurred at Oil Creek might indicate repeated episodes of flowage. In both the Barlow Canyon and Oil Creek areas, the normally clayey Morrison formation grades laterally to massive fine-grained well-sorted grayish- white sandstone that in lithology and stratigraphic position resembles the Unkpapa sandstone—a thick sandstone that replaces the Morrison in the southern and eastern parts of the Black Hills (Darton and Paige, 1925, p. 11). Thick sandstone lenses are un- usual in the Morrison on the west side of the Black Hills, and their occurrence at both folds suggests that the sandstone and the folds are related. No evidence was found of appreciable folding during deposition of the Morrison, however, and the rela- tion, if any, is unknown. REFERENCE Darton, N. H., and Paige, Sidney, 1925, Description of the central Black Hills [with contributions by J. D. Irving]: U.S. Geol. Survey Geol. Atlas, Folio 219, 34 p. B—158 GEOLOGICAL SURVEY RESEARCH 1961 'E' E a t 3 g u: E E 3 3 E g — ——. ( R as w E o: 5 o a: g g '5 D: u é E 3 2 2 _l 3 2 an 2 T, A g 54 N. r 1" ' 53 s L N = o .2 E BARLOW CANYON AREA — = = 3; .2 EXPLANATION < : n: c 2 2 III E = _ fl Sandstone o. .9 g = CL “ 0 3g% a II! 3 5 E Conglomerate I) s. n— U G) = .. v 5 3 E Siltstone w 2:3 Shale A. BARLOW CANYON AREA __ Lak member Calcareous claystone Claystone Limestone E [I] - Covered w = Chert a 8 "' G . L61 __ Glauconlte .‘E s m Carbonaceous material 5 MW 33 = Unconformity .2 5; ,‘J—~~ A 5? Correlation uncertain «a ‘6 fi 4 R. 62 w. E o .. _. = 8 .3 es 3 2 , a: r-* E E L G) D g -—100 3 :1 ”I II) B. OIL CREEK AREA FIGURE 66.2.—Sections showing truncated sedimentary rocks, Sundance, Morrison, and Lakota formations, west side of Black Hills, Wyo. ’X‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—159 67. STRUCTURE OF THE CLARK FORK AREA, IDAHO-MONTANA By J. E. HARRiSON, D. A. JOBIN, and ELIZABETH KING, Denver, 0010., and Washington, D. C. Rocks of the Belt series of Precambrian age have been intruded north of the Hope fault by quartz diorite of Precambrian age (the Purcell sills), and both north and south of the fault by granodiorite of probable Cretaceous age (fig. 67.1). The Belt series here consists of about 40,000 feet of argillites, silt- ites, very fine grained quartzites, limestone, and dolo- mite. The granodiorite, which occurs as small plu- tons and sills scattered throughout most of the mapped area, is virtually identical chemically and petrographically with granodiorite in stocks exposed in the southwestern part of the Packsaddle Mountain quadrangle and with granodiorite in the Selkirk batholith (Gillson, 1927) which borders the Pack- saddle Mountain quadrangle on the north. The regional structural setting is relatively simple. The Hope fault, trending north-northwest across the area, separates a homocline in the Belt rocks to the north from a syncline to the south. The Hope fault also separates an intricate mosaic of steep-sided fault blocks to the south from a simpler mosaic to the north. South of the Hope fault most of the blocks in the eastern part of the area are only slightly tilted and show folds only as drags near each fault. The dip of the beds increases westward in the west limb of the major syncline, and this regional dip has been increased further by tilting of some blocks in the western part of the area. In addition, many of the western blocks show internal folding throughout the block, though blocks that show extensive folding commonly are adjacent to blocks that show only drag folding near the faults. The bounding faults are steep to vertical, as is shown by the nearly straight traces of the faults across a topographic relief of about 4,000 feet. Some of the faults that are sub— parallel in strike appear to converge downward, and a few converge upward. Axes of drag folds are nearly horizontal and thus indicate dip-slip move- ment on the faults. North of the Hope fault the blocks are at most slightly tilted. The principal interruption of the regional homocline is a zone, about 1,500 feet wide, ' of small folds that wrap around the exposed pluton of granodiorite. Metamorphic grade of pelitic rocks is shown by numbers on figure 67.2. Samples indicated by 1’s contain sericite and/or chlorite, but no secondary biotite. Samples indicated by 2’s contain a little secondary biotite but still retain most of their origi- nal clastic texture. Samples indicated by 3’s contain abundant secondary biotite and retain little or no original clastic texture. Correlation between magnetic intensities, expo- sures of intrusive rocks, and metamorphic grade is excellent (fig. 67.2). Each area of exposed intrusive rocks shows up as a positive magnetic anomaly, and the Belt rocks of higher metamorphic grade are ad- jacent to intrusive masses or to positive anomalies. Study of Belt rocks near exposures of intrusive rocks suggests that only Belt rocks within about 2,000 feet of an intrusive body reached grade 3, so the positive magnetic anomalies where no intrusive rocks are exposed most likely represent buried but shallow plutons. The positive anomaly southeast of Clark Fork is the only one that does not have grade 3 rocks around it, and perhaps represents a slightly deeper intrusive body. Because Precambrian quartz diorite is known here only in sills in the Prichard formation and only north of the Hope fault (Ander- son, 1930, pl. 14), all positive anomalies except the two at the north-central edge of the area probably represent bodies of Cretaceous( ?) granodiorite. Four of five joint sets common in the Belt rocks of the area are subparallel to four principal sets of block faults. It seems unlikely that the joints, which are products of tension, were formed at the time of the faults, which are products of shear. An interpretation of the data available to date is shown in figure 67.3. The position of these sec— tions is shown on figures 67.1 and 67.2. The struc- tural rise from right to left in the sections is ac- companied by a general stepping down of the blocks in the same direction. Some of the structural rise is toward an anticlinal crest, but part of it may also be due to upward pressure from a rising magma. If all the pressure had been upward, then sets of shear planes dipping about 45° should have formed, as they commonly do over salt domes. Because the faults are steep, they probably reflect a fracture pattern, perhaps originally expressed only by joints, established during regional folding. Local folding within certain of the keystone blocks, however, must have been in response to an upward punch, for some of the keystones are upside down (bounding faults known to converge upward); only an upward push GEOLOGICAL SURVEY RESEARCH 1961 B—160 .mcgcofiénwg 63:53an 53582 vaamxuwm 2.3 we 939 was Susagvanv Mich ”.230 as» we 3:: omwfloou voszapwcwolésw 552m .l.|4lll.|] O wmflim 8&2: .58: Ag 9; 52%: m a 3 $280 boo? «XIX Bu; . E9582 233x03 Q baawv boom: Nddfiwmc QZMR QNVQ % . I. V . In: info: NVIHEIWVDEHd .5333 we NEE \ V Tlivx moon _S:osiom mm mug we .5. was 35m \ cm 3%. fiSESSEfi :c :3 3:3 :5 .wwimxg wswxg fiufioQ 25mm .u..nnllh.l\ 8330 =o5a§8 infirm scam—ES 3.5m sagas nag (050033 33.5% 326x AMVN *EBLVHO NVIHSWVDEHd .L 411383 negate.”— mwmwm um W Emu—wipe wag—w? 5358 38m 32% W Era—Ea 3:5 3E6 5525. 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Ewnmum. ucm 923sz .._ ._., B xwtzm uzwcmmEEm< mmfiz m o N ‘3 .wmmfi demuEmm Eta 92: 6 :3 5383538 E @280 A \I\ H V . _ _ _m can m m .0mo0~fi 3% 53: 3:»: w: m “:29 233k. 33* 3: \o S33 3323:” 3229 mm :e 333 $33 LSD .méafiofis :KSQSE 8 N33»: 32?: 3:: $53? :9in5 a§§auém :mwiwg 33358 M62259: 3. 3:3 .5 Swim‘xfi 233: EfiuQ 53:8 ozocwafiouwa 57:35 Eek /§\ :Sgggaem .E.\ was uwm. mv—uo: :wm me 355 3:92:33: m .N J 8% :SES:3% Sc :3 SE 53% flash I\\\ 312: 5:26 :atnfiwofim F 3:29:55 $980530 ZO_._. 1% g m Michoud gravel >- c: 7 <1 Unmapped areas and rocks mostl Y “E older than the Raft formation to American Falls lake beds, L; ~——._-—— including some Raft formation 3 Contact, approxmately located southwest of American Falls 0 _l__i__.__i____._ Terrace boundary 5 0 5 MILES ' l 1 l i 1 l l CONTOUR INTERVAL 200 FEET 42°3o‘ Geology by 0. E. Trimble and we. Con FIGURE 69.1.—Sketch map of the American Falls-Pocatello area showing generalized distribution of upper Quaternary rocks. (fig. 69.1). It rests conformably on the unweath- ered surface of the American Falls lake beds, and it is limited areally at most places by two scarps, an upper one against which the gravel was de- posited, and a lower one Which is a lake-cut scarp at the back of the younger Aberdeen terrace (fig. 69.1). The surface of the Michaud gravel was terraced, scoured, and channeled, and the prominent Aber- deen terrace, which is partly lacustrine and partly fluviatile, was cut on the gravel on the east side of the American Falls reservoir. The scours and channels are higher and older than the Aberdeen terrace, or are graded to it. B—166 l \\\\ //American Falls\ // Reserlml / / \ \ / / / / - 2 ’4. ° 3 / 0 9; / a / m /ud 0‘ v. gee § m 0 l 2 3 4 5 I I l I A l 6 MILES FIGURE 69.2.—Distribution of maximum boulder size in the Michaud gravel. Contours (in feet) of size larger than cobble. Dashed where no control available. The Michaud gravel is 50 to 80 feet thick. The basal contact of the Michaud gravel with the Ameri- can Falls lake beds is uniformly about 4,400 feet in altitude, and its upper surface ranges from about 4,450 to 4,480 feet in altitude. The distribution of maximum boulder size in the Michaud gravel was mapped during the summer of 1960 (fig. 69.2). The contours show the rapid de- crease in size away from the mouth of the Portneuf River canyon. At Pocatello, the gravel consists mainly of large boulders derived almost entirely from the Portneuf valley. East of Bannock Creek, near Michaud, the deposit is a cobbly gravel, but west of Bannock Creek it is a pebbly sand. Correla- tive deposits consisting mainly of fine sand and silt cover’the Grandview terrace west of the American Falls reservoir (fig. 69.1). The maximum diameter of boulders (about 8 feet) in the Michaud gravel at Pocatello suggests that the transporting stream had an unusually high velocity. Observations of Barrel], cited by Rubey (1952, p. 71), imply that stream velocities of between 4 and 12 miles per hour are necessary to move a cobble about 6 inches in diameter. Inasmuch as the radius of the largest object moved by a stream varies with the GEOLOGICAL SURVEY RESEARCH 1961 square of the velocity, an 8-foot boulder~ probably indicates a current velocity of between 16 and 48 miles per hour. These are very broad and approxi- mate limits, but when this general order of magni- tude is compared with a median velocity of 3.54 miles per hour for the Mississippi River during one of its greatest floods (Rubey, 1938, p. 137), and with a maximum recorded velocity of about 16 miles per hour for any natural stream (Howard F. Matthai, oral communication, 1960), it is evident that the stream responsible for the Michaud gravel attained abnormal size and velocity, at least temporarily. Such a great stream in the Pocatello area could only have been the river flowing from Lake Bonneville. Other evidence of flooding along the. Bonneville river has been discussed by Malde (1960, p. B295— B297). The Michaud gravel has been dated late Pleisto- cene on the basis of mollusks (D. W. Taylor, written communication, 1960) and vertebrates, including Bison alleni (Hopkins, 1951, p. 195), found in the gravel. Now, however, the age of the Michaud gravel (and the time of overflow of Lake Bonneville) can be more nearly fixed. A radiocarbon date (W—929) for a peat layer 13 feet below the top of the American Falls lake beds is > 42,000 years B.P. (before present) according to Meyer Rubin (written com- munication, 1961), and shells (W—731) from the Aberdeen terrace deposit are dated at 29,700 1 1,000 years B.P. (Trimble and Carr, in press). The Michaud gravel probably was deposited, therefore, about 30,000 to 40,000 years ago. REFERENCES Gilbert, G. K., 1890, Lake Bonneville: U.S. Geol. Survey Mon. 1, 438 p. Hopkins, M. L., 1951, Bison (Gigantobison) ldtifrons and Bison (Simobison) alleni in southeastern ’Idaho: Jour. Mammalogy, v. 32, p. 192—197. Malde, H. E., 1960, Evidence in the Snake River Plain, Idaho of a catastrophic flood from Pleistocene Lake Bonneville, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400—B, p. B295—B297. Rubey, W. W., 1938, The force required to move particles on a stream bed: U.S. Geol. Survey Prof. Paper 189—E, p. 121—141. 1952, Geology and mineral resources of the Harden and Brussels quadrangles (in Illinois): U.S. Geol. Survey Prof. Paper 218, 179 p. Trimble, D. E., and Carr, W. J., (in press), Late Quaternary history of the Snake River in the American Falls region, Idaho: Geol. Soc. America Bull. ’X‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 13—167 70. VOLCANIC ASH BEDS As STRATIGRAPHIC MARKERS IN BASIN DEPOSITS NEAR HAGERMAN AND ' ‘ GLENNS FERRY, IDAHO By HOWARD A. POWERS and HAROLD E. MALDE, Denver, Colo. The upper Cenozoic detrital deposits exposed along the Snake River downstream from Hagerman, Idaho, contain numerous thin beds of siliceous volcanic ash that are indistinguishable in the field but that differ Significantly in physical and chemical proper— ties. By study Of these properties several distinc- tive ash beds have been identified in discontinuous, widely separated outcrops. These ash beds can be used to demonstrate the stratigraphic relations of deposits otherwise devoid of marker beds, and they are indispensable, therefore, for recognizing facies changes and basin deformation. This paper de- scribes two such beds of volcanic ash in a formation of late Pliocene and early Pleistocene age near Hagerman and Glenns Ferry. Significant chemical comparisons of volcanic ash beds require laboratory separation of clean unal- tered glass. The analyses given here are of glass shards scrubbed by ultrasonic agitation, separated from phenocrysts and other contaminants by flota- tion in diluted bromoform, and further cleaned by feeding through a Frantz magnetic separator. The cleaned shards in such samples are colorless and completely isotropic. PETERS GULCH ASH LAYER The Peters Gulch ash layer is named informally for Peters Gulch, 4 miles southwest of Hagerman, where sample E1810 was collected (fig. 70.1). The distinctive physical and chemical properties that identify this bed were determined from nine samples. Physically, the ash consists of about equal parts of extremely vesicular pumice grains and of complexly shaped glass shards, both of which are very weakly magnetic in the strong field of a Frantz separator. The particular combination of phenocrysts embedded in the glass Shards (chevkinite, zircon, ilmenite, and magnetite) is different from the phenocryst assem- blage in 60 samples from all other ash beds exposed in this region. (For descriptions of chevkinite in other ash beds, see Young and Powers, 1960.) Chemi- cal analyses Of glass shards separated from the ash are listed in table 1. Seven of the samples collected at various places along 3 miles of continuous out- crop from Peters Gulch northward indicate the variation found in amounts of constituents. Com- parison with the 60 samples of other analyzed ash beds in this region shows that the Peters Gulch ash layer is highest in Cl, La, and Sn, and lowest in Ba and Sr. In brief, no other ash samples have the same combination of physical properties and chemi- cal constituents. Confident correlation of the Peters Gulch ash layer between localities as widely spaced as 24 miles (fig. 70.1) helps to reconstruct the terrain on which it was deposited. Where the ash is recognizable, it occurs as a bed a few inches thick, either in car- bonaceous shale or in thin-bedded silt and clay. These fine-grained materials probably accumulated on a flood plain, as is suggested by paleoecological evidence and by sedimentary features (Malde and Powers, 1958). At the time of the ash fall this area may have been the floor of a broad, flat valley dotted with sloughs, shallow lakes, and a few channels along which the water moved sluggishly. Where the ash fell in slack water or on boggy ground, it had some chance for preservation as a recognizable bed, but where the ash fell in a channel, it was carried by currents and mixed with other debris. The sedimentary equilibrium of a broad, flat valley implied by the fine-grained materials associated with the Peters Gulch ash layer is seemingly contradicted by the lithologic dissimilarities of the sediments that occur considerably above and below the beds in which the ash is found. At Peters Gulch the section consists dominantly of thin-bedded silt and clay with some fine sand and carbonaceous shale. In con- trast, the section at King Hill consists of a massive sequence of coarse sand and fine gravel. At Clover Creek units of these different lithologies alternate. Such contrasting facies can be accounted for by the local geography. The deposits at Peters Gulch ac- cumulated several miles from the margins of the basin, whereas those at King Hill were brought to the northern margin of the basin by steeply graded streams that drained granitic outcrops a few miles farther north. The mixed deposits at Clover Creek are in an intermediate position. The presence of the ash shows that sedimentation at these places was concurrent. Differences in altitude of the Peters Gulch ash layer, as Shown in figure 70.1, are mostly accounted for by displacements on high-angle faults that sep— B—168 GEOLOGICAL SURVEY RESEARCH 1961 @ AltitudE, in feet fi— King Hill 3600 ‘ Clover Creek 0 cocoa Altitude, ® a o o a in feet l 0 005° _ 3200 Morrow Reservour —— a on 3500— a can: 9 ”0°; Peters Gulch o o o o n o o — 3100 -- ”50°? 3400 a \ - 3000 “ 3300 J 63053 CD 5/ (Covered) The Narrows 5/ — 2900 " {4/ 3200 — :9/ 0/ Q/ / mm... / C d _ 2800 ( overe ) __ 3100 - l. 2700 —- 3000 — _ 2600 —— 2900 — 63043 . ‘ (Covered) l l . . _ 2500 —— (Covered) (Covered) 2800 d 115“30’ 114°45' EXPLANATION } H\ 43"05’ Basalt 1 D- \W Massive silt Guinea 0! ash- bearinz denoslls Volcanic ash /@ Location ol Columnar some" Thin-bedded silt and clay Carbonaceous shale OHagerman Fine sand 0 “.0 —42°45' Coarse saan; nd gravel Volcanic ash sample Area of "‘39 10 W 42°40' 2'0 MILES FIGURE 70.1.—Genera1ized columnar sections and outline geologic map of ash-bearing deposits of late Pliocene and early Pleistocene age near Hagerman and Glenns Ferry, Idaho. Sections 1, 2, and 3 are each overlain by about 30 feet of basalt of middle Pleistocene age. Section 5 is overlain by 55 feet of alluvium of early Pleistocene age. The beds lie nearly hori- zontal at places where the sections were measured. [Chlorine analyses by V. C. Smith. Other chemical analyses as follows: sample E1810 by P. M. Montalta; samples E2308, B441. B443, E2309, B442, and B414 by SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 TABLE 1.fAnalyses of prepared samples of glass shards from the Peters Gulch ash layer B—169 L. N. Tarrant; sample E1919 by M. R. Kittrell; and sample G3052 by V. C. Smith. Quantitative spectrographic analyses by P. R. Barnett. . . . indicates not determined] Chemical analyses Sample N 0. Location of sample Si02 A1203 TiOz F6203 F80 MnO MgO CaO N320 K20 Cl F P205 C02 H20 E1810 Sec.5at Peters Gulch..... 69.82 12.49 0.12 0.77 1.10 0.05 0.13 0.59 2.32 6.72 ..... 0.104 0.01 ..... 5.19 E2308 1.9 mi. N. of Peters Gulch. ........................................... 2.46 6.63 0.243 .103 .......... 5.10 B441 2.2 Do ............................................................ 2.48 6.34 .252 .098 .......... 5.29 B443 2.3 Do ............................................................ 2.42 6.57 ..... .098 .......... 5.07 E2309 2.6 Do ............................................................ 2.64 6.57 .252 .103 ................. B442 2.8 Do ............................................................ 2.43 6.33 ..... .098 ..... 5.05 B414 2.9 Do ................ 69.56 12.35 .12 .77 1.10 .03 .08 .52 2.49 6.48 ..... .106 .00 ..... 6.11 E1919 Sec.3nearKing Hill...... 70.03 12.62 .13 .67, 1.21 .04 .02 .56 2.26 6.16 .243 .103 .02 0.00 5.70 G3052 Sec. 4 at Clover Creek. . . . ...................................................... .246 .106 ................. Quantitative spectrographic analyses Sample No. Location of sample B Ba Be Cu Ga La Mo Nb Pb Sn Sr V Y Yb Zr E1810 Sec. 5 at Peters Gulch... . . 0.006 0.005 0001100008 0.0033 0.014 0.0006 0.007 0.002 0.00110.0010 <0.0002 0.009 0.0008 0.043 E2308 1.9 mi. N. of Peters GulCh. .007 .004 .0011 .0008 .0039 .008 .0004 .006 .002 .0009 .0008 < .0002 .006 .0007 .043 B441 2.2 Do ................ .006 .006 .0008 .0010 .0040 .014 .0006 .008 .002 .0012 .0009 < .0002 .009 .0008 .048 B443 2.3 Do ................ .005 .006 .0013 .0009 .0036 .016 .0005 .009 .002 .0012 .0008 < .0002 .011 .0008 .056 E2309 2.6 Do ................ .008 .005 .0010 .0009 .0038 .008 .0004 .006 .002 .0008 .0020 < .0002 .006 .0006 .040 B442 2.8 Do ................ .006 .007 .0011 .0010 .0038 .013 .0005 .007 .002 .0012 .0012 < .0002 .009 .0008 .046 B414 2.9 Do ................ .007 .003 .0012 .0009 .0036 .013 .0006 .007 .002 .0011 .0005 < .0002 .009 .0008 .039 E1919 Sec. 3 near King Hill ...... .008 .008 .0010 .0008 .0034 .012 .0004 .008 .001 .0012 .0007 .0002 .008 .0007 .048 G3052 Sec. 4 at Clover Creek. . . . .007 .005 .0009 .0008 .0040 .009 .0004 .006 .002 .0009 .0005 .0002 .007 .0006 .030 arate the section at Clover Creek from King Hill tinctive combination of physical and chemical prop- and Peters Gulch. erties that identify this bed were determined from three samples. Physically, the ash is made up of THE NARROWS ASH LAYER complexly shaped shards, some shards that are The Narrows ash layer is named informally for Simply curved, and a few grains 0f pumice, all Of the Narrows, 5 miles west of Glenns Ferry, where which are nonmagnetic. The phenocrysts are brown sample G3123 was collected (fig. 70.1). The dis- hornblende, orthopyroxene, clinopyroxene, and mag- TABLE 2,—Analyses of prepared samples of glass shards from the Narrows ash layer [Chlorine and fluorine analyses by V. C. Smith. Chemical analysis of sample G3123 by D. F. Powers. Semiquantitative spectrographic analyses by R. G. avens. . . . indicates not determined] Chemical analyses Sample N 0. Location of sample S102 A1203 Ti02 F9203 FeO MnO MgO CaO N320 K20 Cl F P205 002 H20 G3123 Sec.1attheNarrows ..... 72.18 12.40 0.22 0.47 0.64 0.04 0.26 1.14 2.92 4.340.1150.02O 0.04 0.01 4.70 G3053 Sec. 2 at Morrow Reservoir ...................................................... .109 .016 ................. G3046 1 mi. S. of Morrow Res.. .. ...................................................... .115 .018 ................. Sample Semiquantitative spectrographic analyses 0. Location of sample B Ba Ba Cu Ga La. Mo Nb Pb Sn Sr V Y Yb Zr Hf, , . G3123 Sec. 1 at the Narrows. . . 00020.07 <0.0001 0.0007 0.0007 <0.003 <0.0005 <0.001 <0.001 <0.0050.0070.0010.001000010.007 G3053 Sec.'2 at lVlorroW ReserVOIr .003 .07 < .0001 .0007 .0007 < .003 < .0005 < .001 < .001 < .005 .007 .001 .001 .0001 .007 G3046 1 m1. S. of Morrow Res. .. .003 .07 < .0001 .0007 .0007 < .003 < .0005 < .001 < .001 < .005 .007 .001 .001 .0001 .007 B—170 netite. Chemical comparison with the 60 samples of other ash beds in this region shows that the ash is very low in F, Ga, Y, Yb, and Zr (table 2). The isolated outcrops Where the Narrows ash layer is identified are not much alike and could not be correlated otherwise. The section at the Narrows is sandy with many beds of carbonaceous shale, whereas the section at Morrow Reservoir has fewer beds of carbonaceous shale and more layers of thin- bedded silt and clay. Apparently the ash fell on boggy ground or on a mud flat at the Narrows and in a body of slowly moving water at Morrow Reservoir. The ash bed is now 400 feet lower in altitude at the Narrows than at Morrow Reservoir, but like -the Peters Gulch ash layer it was probably de- GEOLOGICAL SURVEY RESEARCH 1961 posited on the floor of a broad, flat valley. If so, the present difference in altitude demonstrates moderate basin deformation. Because no faults were found during mapping, this difference in altitude is at- tributed to an average southwestward tilt of about 50 feet per mile. The stratigraphic relation of the Peters Gulch ash layer to the Narrows ash layer has not been deter- mined, but as more ash beds are identified a com- plete local sequence probably will be established. REFERENCES Malde, H. E., and Powers, H. A., 1958, Flood-plain origin of the Hagerman lake beds, Snake River Plain, Idaho [abs.] : Geol. Soc. America Bull., v. 69, no. 12, pt. 2, p. 1608. Young, E. J., and Powers, H. A., 1960, Chevkinite in volcanic ash: Am. Mineralogist, v. 45, nos. 7—8, p. 875—881. 6% 71. PATTERNED GROUND OF POSSIBLE SOLIFLUCTION ORIGIN AT LOW ALTITUDE IN THE WESTERN SNAKE RIVER PLAIN, IDAHO By HAROLD E. MALDE, Denver, 0010. A distinctive geometric pattern formed by soil mounds and stone pavements, which resembles the patterned ground of polar regions (Washburn, 1956), occurs on the dissected plateaus and marginal collu- vial deposits north of the Snake River near Glenns Ferry, Idaho (figs. 71.1 and 71.2). The mounds and stone pavements are typically developed on gravel fans and on basaltic lava flows, but they are found also on such diverse materials as lake beds and welded tufl‘——all of middle Pleistocene or older age. Because the patterned ground is not developed on lithologically similar younger deposits in the same region, it is regarded as a relict landform. This paper concerns only the patterned ground in areas of basalt and gravel. The soil mounds are monotonously uniform, par- ticularly in relatively flat areas. A typical mound is circular, from 50 to 60 feet in diameter, and 3 feet high at the center. Generally the mounds are regularly spaced from 60 to 85 feet apart, measured from their centers. They are surrounded by a pave- ment of stones. Lithologically, the mounds consist mostly of friable light-colored silt that contains some angular fragments from the underlying rocks. These fragments usually are the size of pebbles, but a few are as large as cobbles and boulders. Below a depth of 18 inches the mound material is compact, loamy, and darken—seemingly a consequence of soil de- velopment—and rock fragments are more numerous. At a depth of 3 to 4 feet below the center of a mound, the mixture of silt and rock fragments grades down- ward rather abruptly into tightly packed gravel (or broken basalt), which emerges at the periphery of a mound to join the surrounding stone pavement. The stone pavements that surround the mounds ordinarily consist of well sorted angular stones, which range from cobbles to boulders. A few of the stones are fractured. Depending on the spacing of the mounds, the pavement areas pinch and swell, in places being as much as 20 feet wide. At a few localities, where the mounds are far apart, the pave- ment areas form rubbly fields more than 100 feet across. The stones of the pavement that are tabular shaped commonly are oriented on edge and are turned parallel to the margins of the pavement so as to occupy the least space side-to-side (fig. 71.3). SHORT PAPERS IN THE GEOLOGIC AND'HYDROLOGIC SCIENCES, ARTICLES 1-146 FIGURE 71.1.—Vertical aerial photograph of patterned ground on part of a basalt plateau and on marginal blocky colluvium 9 miles northeast of Glenns Ferry, Idaho. The light colored spots on the plateau are mounds of silt covered with grass and sagebrush. The barren darker ground, which forms a network surrounding the mounds, consists of blocks dislodged from the underlying basalt. The light colored bands that trend downslope on the colluvium are also grass-covered silt. These strips of soil separate darker bands of sorted basalt fragments. The plateau slopes 1° southwestward, and the colluvium slopes 15° southeastward. The area shown is about 3,600 feet above sea level. culture aerial photograph DLG—7G—98 taken Oct. 22, 1950.] These upturned stones are so tightly wedged that several must be dislodged in order to remove one. They make the pavement comparatively rough, and large surface areas of the stones that comprise the pavement consequently are exposed to weathering. These stone surfaces are encrusted with lichens. Be- low the pavement layer the stones are smaller, less well sorted, and randomly arranged. In some basalt areas, stone fragments that are recognizably articu- lated with the underlying lava occur at a depth of 1 or 2 feet, and it is possible to walk at other places from a stone pavement onto a bare lava surface. In gravel areas, also, apparently undisturbed gravel occurs at a shallow depth. [Enlarged from U.S. Department of Agri- The regular pattern expressed in flat areas by the soil mounds and stone pavements changes progres- sively to parallel bands of soil and stones as the angle of slope increases. Where the angle of slope is less than 1°, the mounds’are fairly equally spaced and the stone pavements form rectangular or polygo- nal networks (area A of fig. 71.1). In areas of some- what greater slope, where drainage channels are defined, the mounds are arranged in parallel rows separated by continuous gutterlike shallow troughs paved with stones (area B of fig. 71.1). On slopes of about 6°, the mounds are elliptical and the downhill sides of some encircling nets of stone pavement are broken so that adjacent mounds are connected down- B—172 o 5000 FEET I__L_J CONTOUR INTERVAL 40 FEET FIGURE 71.2.——Topographic map of the area 9 miles northeast of Glenns Ferry, Idaho, shown in the vertical aerial photograph reproduced as figure 71.1. slope by a strip of soil (not well illustrated in fig. 71.1). At slope angles between 6° and 15°, most of the mounds are connected by such narrow strips of soil, much like beads on a string, and the pave- ment areas form continuous rocky bands. These al- ternate parallel bands of soil and stones trend di— rectly downslope (area C of fig. 71.1). On slopes of 15° to 30°, the mounds along the bands of soil are indistinct, whereas lines of stone pavement are prominent (area D of fig. 71.1). On slopes steeper than 300, a sorted pattern of soil and stones gen- erally cannot be recognized. Even though the patterned ground in flat areas differs from that on the slopes, the gradational change in pattern from one place to the other sug- gests that a similar process accounts for both. These gradational changes in pattern resemble the pro- gressive modification of polygonal ground by soli- fluction on increasingly steeper slopes, as observed by Holmes and Colton (1960) near Thule, Green- land. The soil mounds and stone pavements near Glenns Ferry apparently are now stable, as indicated by soil development and lichen growth, so the mechanism by which they formed can only be inferred. How- ever, their great similarity to the patterned ground of polar regions implies development by frost sorting and by solifluction. If so, the patterned ground near Glenns Ferry may have developed during a former period of cooler and wetter climate. Patterned ground that resembles the soil mounds and stone pavements near Glenns Ferry is reported elsewhere in the northwestern States. For example, GEOLOGICAL SURVEY RESEARCH 1961 FIGURE 71.3.—-A narrow stone pavement between soil mounds in an area of gravel at 3,900 feet altitude 12 miles north of Glenns Ferry, Idaho. Tabular stones are steeply or vertically oriented and are alined parallel to the margins of the pavement. The ruler is 7 inches long. analogous patterned ground occurs on plateau basalt in eastern Washington and Oregon (Freeman, 1926; 1932; Waters and Flagler, 1929; and Kaatz, 1959) and on gravel fans and lava flows near Mount Shasta, California (Masson, 1949). A study of the distri- bution of such patterned ground, and a better un- derstanding of its origins, could determine the former southward extent of cold and wet climatic conditions in this region and would help to establish ages for the land surfaces on which the pattern is found. REFERENCES Freeman, 0. W., 1926, Scabland mounds of eastern Washing- ton: Science new ser., v. 64, no. 1662, p. 450—451. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 Freeman, 0. W., 1932, Origin and economic value of the scab- land mounds of eastern Washington: Northwest Sci., v. 6, no. 2, p. 37—40. Holmes, C. D., and Colton, R. B., 1960, Patterned ground near Dundas (Thule Air Force Base), Greenland: Medd. om Gronland, v. 158. no. 6, 15 p. Kaatz, M. R., 1959, Patterned ground in central Washington; a preliminary report: Northwest Sci., v. 33, no. 4, p. 145- 156. B—173 Masson, P. H., 1949, Circular soil structures in northeastern California: California Div. Mines Bull. 151, p. 61—71. Washburn, A. L., 1956, Classification of patterned ground and review of suggested origins: Geol. Soc. America Bull., v. 67, p. 825—866. Waters, A. C., and Flagler, C. W., 1929, Origin of thc .uall mounds on the Columbia River Plateau: Am. Jour. Sci., 5th ser., v. 18, p. 209—224. 5% 72. COLLAPSE STRUCTURES OF SOUTHERN SPANISH VALLEY, SOUTHEASTERN UTAH By G. W. WEIR, W. P. PUFFETT, and C. L. DODSON, Menlo Park, Calif, Corbin, Ky., and Decatur, Ala. Work done in cooperation with the US. Atomic Energy Commission Southern Spanish Valley, a few miles southeast of Moab, Utah, lies in a syncline of Mesozoic rocks that is superimposed on the subsurface salt-cored Moab anticline in late Paleozoic rocks (Baker, 1933; Shoemaker and others, 1958). On the east flank of the syncline are many small collapse structures (figs. 72.1 and 72.2). Most of the collapse structures are roughly oval in plan, a few hundred feet in diameter, and contain a mass of broken rock that has been dropped several hundreds of feet. They are found in all exposed formations from the Navajo sand- stone (Triassic? and Jurassic) of the Glen Canyon group through a sandstone member of the Mancos shale (Upper Cretaceous)—a stratigraphic range of more than 3,000 feet. Although the vertical exposure of any of these collapse structures is only about 200 feet, they are inferred to be breccia pipes that extend several thousand feet below the surface. Forty-five collapse structures were identified in and near southern Spanish Valley (fig. 72.1); an additional 33 collapse structures were noted in a reconnaissance north of this area to Moab. Most of the collapse structures lie on the east side of Spanish Valley within a northwest-trending belt that is about three-quarters of a mile wide and 10 miles long. The three collapse structures south of Pack Creek may be in another more westerly trending belt. Most of the collapse structures are partly obscured by surficial deposits and form inconspicuous mounds or swales. The sharp boundaries of these structures are fault contacts that, in plan, consist of many short straight segments enclosing the core of broken rock (fig. 72.3). The bounding faults commonly dip steeply inward, but several outcrops of wavy fault planes suggest that they average about vertical. Dis- placements along these faults range from a few hundred feet to about 1,500 feet and may differ greatly in adjacent collapse structures. The breccia within the bounding faults is made up of the country rock and younger sedimentary for- mations. In several collapse structures the breccia is roughly segregated into small mappable units (fig. 72.3), but more commonly the breccia is a jumbled mixture of fragments from many forma- tions. The fragments within the breccia, which range from grains to huge blocks 50 feet across, are not slickensided, and the sand grains are not crushed and sheared. In general, the breccia is little altered except for the effects of removal of carbo- nate cement from sandstone units. For example, the breccia fragments are generally more friable than their parent rocks, and sandstone dikes and veinlets are common both in the breccia core and in the sur- rounding country rock. The edge of the core of the collapse structure south of the M4 Ranch locally shows a well-developed foliation that parallels the boundary fault; this foliation apparently resulted from flowage of the decemented sand and stretching B—174 GEOLOGICAL SURVEY RESEARCH 1961 Spanish Valley dotted where concealed. D, downthrown side 109°3o' 109.15. . . L:GRAND COUNTY EXPLANATION 3B 30 . - c ‘ SAN JUAN COUN Y '\ ' A: II JS \ T' \\ , I L” >- ' \ \\\\\\ I- II \\\\\ \\\\\ \\ < < \\\\\\\\K_\\\\\\\ 3 Z ‘ X\\\\\\\\\\\:\: 0 :{S‘i/g E /\\ J’: 5 Igneous rocks E Chiefly dion‘te porphyry E \\ \\\ l u) A 1‘13: ff 3 \\ . Lu 0 Mane )s shale, Dakota sandstone, 56 at d Burro Canyon formation — =5: — Morrison formation L_) m m .. a 'JS: \\\ \\ \ \ \_ ,/ ,5 3 J 1111\\\1\\‘\\ \\ /\\/':7‘/‘\‘ :W San Rafael group ‘1 m \\\\\ \\\\\ ‘ \ /, /\ \\\ \\\\\\\\\ \\\ ‘1 Iggy/MAS \ \ C ‘1 17., ‘ . I? I53 0 J5 Glen Canyon group a ‘2 \ \ \\ _ 38° 15/ r \“ \\\‘ \\\\\\\\ \\\\\\\\:\ \\\\\\:\ \\\\ E \ \ \\ \\\ . . Js$\\\ E \\E\ 2\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\1\\\\\\\\ \ Chmle formatlon . _____ Geology by G. W. Weir, —' Z 5— 1| 9 i 12 13 ‘l i’M'LES w. P. Puffett, C. L. Dodson. “"mm ‘7, 5 . —--—1 and V. C. Kennedy, 1956—59 . 22 ll Salt Lake City l Hermosa formatlon E g I . _ _ ‘ _ _ - D. l UTAH I. / \ / D ' -. ' I Moab 0 ' Contact High-angle fault Collapse structure fl . . Dashed where awrommately located Dashed where approximately located; | l I l ._ ________ J FIGURE 72.1.—Generalized geologic map of southern Spanish Valley and environs, Utah, showing location of section A—A' (fig. 72.2) and location of geologic map of collapse structure (fig. 72.3). of clay particles in the sandstone. Some breccias are locally stained by iron and manganese oxides, but they do not resemble the hydrothermally altered breccias in the somewhat similar collapse structures of the San Rafael Swell (Kerr and others, 1957). The collapse structures are Tertiary in age, for they are overlain by early Pleistocene deposits and likely all the collapse structures bottom in inclined Paleozoic limestone beds that flank the salt core of the Moab anticline beneath Spanish Valley, because displacements of many of the breccia cores exceed the thickness of the underlying Mesozoic rocks. The origin of these collapse structures is uncertain but may be hypothesized as follows: Connate water, they cut rocks as young as Late Cretaceous. Most perhaps admixed with hydrothermal solutions, La Sal Mountains A A’ 10000 '1 10,000 A Spanish Valley Collapse structur SEA LEVEL :Ei—“t — ‘ _ "‘ “'— SEA LEVEL —»—- —UJ 5 MlLES J Ti, Tertiary intrusive rocks, chiefly in laccoliths and stocks; MC, Mesozoic clastic rocks; He, Paleozoic elastic rocks; le, Paleozoic limestone; Pze, Paleozoic evaporites, chiefly salt (Quaternary deposits not shown) FIGURE 72.2.—Generalized section A—A’ across southern Spanish Valley and environs, Utah. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 \\50 \~\55 \7o\‘35 67 \‘QE Y7 Jiu \u 72\\‘ I ',/" \ 60 \ —O 100 2(1)0 l 390 FEET CONTOUR INTERVAL 40 FEET DATUM l5 APPROXIMATE MEAN SEA LEVEL Geology and topography by G. W. Weir and W. P. Puffett, 1956 EXP LA N AT l O N lBRECClA UNITS —--—N / // \__/ / Approximate contact KT‘—’/ 90 80 Fault, showing dip 041st where approximately located Dakota sandstone (Upper Cretaceous) 51% Burro Canyon formation (Lower Cretaceous) /(70 Strike and dip of beds / Vertical joint Morrison formation (Upper J urassic) me, Brushy Basin member. /‘/70 ”“5! Salt Wash member Strike and dip of joints Entrada sandstone (Upper Jurassic), Camel N formation (Upper and Middle Jurassic), and Navajo sandstone (Jurassic and Triassic(7) undivided COUNTRY ROCK J‘fin Navajo sandstone (Jurassic and Triassic?) FIGURE 72.3.—Simplifled geologic map of collapse structure, northeast rim of Spanish Valley, Utah. B—175 moved downslope from igneous domes of the La Sal Mountains during the Tertiary and dissolved lime- stone in the upturned Paleozoic beds in the sub— surface near Spanish Valley and thus created space for collapse breccia from the overlying formations. Moving upward along fracture channelways in the younger formations, the solutions removed carbonate cement so that these younger rocks caved into the open spaces. If these inferences and hypothesis are approximately correct, the collapse structures are the outcrops of breccia pipes that are as much as 5,000 feet high. The collapse structures of Spanish Valley are not known to be' mineralized, but they resemble in part other pipelike bodies of brecciated sedimentary rock that contain uranium ore such as the Temple Moun- tain collapse structure, Utah (Kerr and others, 1957; Keys and White, 1956), the Woodrow pipe, New Mexico (Hilpert and Moench, 1960), and the Orphan pipe, Arizona (Gabelman and Boyer, 1958). REFERENCES - Baker, A. A., 1933, Geology and oil possibilities of the Moab district, Grand and San Juan Counties, Utah; U.S. Geol. Survey Bull. 841, 95 p. Gabelman, J. W., and Boyer, W. H., 1958, Relation of uranium deposits to feeder structures, associated alteration, and mineral zones: Proc. Second United Nations Internat. Conf. on the Peaceful Uses of Atomic Energy, Geneva, Switzerland, v. 2, p. 338—350, 7 figs. Hilpert, L. S., and Moench, R. H., 1960, Uranium deposits of the southern part of the San Juan Basin, New Mexico: Econ. Geology, v. 55, p. 429—464. Kerr, P. F., Bodine, M. W., Jr., Kelley, D. R., and Keys, W. W., 1957, Collapse features, Temple Mountain Uranium area, Utah: Geol. Soc. America Bu11., v. 68, p. 933—982. Keys, W. W., and White, R. L., 1956, Investigations of the Temple Mountain collapse and associated features, San Rafael Swell, Emery County, Utah in Page, L. R., Stocking, H. E., and Smith, H. B., Contributions to the geology of uranium and thorium by the United States Geological Survey and Atomic Energy Commission for the United Nations International Conference on Peaceful Uses of Atomic Energy, Geneva, Switzerland, 1955: US. Geol. Survey Prof. Paper 300, p. 285—298. Shoemaker, E. M., Case, J. E., and Elston, D. P., 1958, Salt anticlines of the Paradox basin, in Geology of the Paradox Basin: Intermountain Assoc. Petroleum Geologists Guide- book, 9th Ann. Field Conf., 1958, p. 39—59. 5% , B—176 GEOLOGICAL SURVEY RESEARCH 1961 73. AGE RELATIONS OF THE CLIMAX COMPOSITE STOCK, NEVADA TEST SITE, NYE COUNTY, NEVADA By F. N. HOUSER and F. G. POOLE, Denver, Colo. Work done in cooperation with the US. Atomic Energy Commission The Climax composite stock consists of two sep- arate, contiguous intrusive masses, a granodiorite and a quartz monzonite that do not necessarily differ greatly in age (Houser and Poole, 1960a). On the basis of crosscutting relations and of chemical and mineralogic characteristics observed in hundreds of feet of drill core and an 800-1evel tunnel, as well as in surface outcrops, it is concluded that the quartz monzonite is the younger. Numerous aplite and peg- matite dikes cut both masses. Field relations and a lead-alpha age determination (T. W. Stern, written communication, 1960) suggest an age for the Climax composite stock of Permian(?) to early Mesozoic. The Climax stock intruded complexly folded and faulted carbonate rocks of the Pogonip group of Ordovician age. In fault contact with the Pogonip group are sedimentary rocks of Cambrian to pos- sible Pennsylvanian age. The carbonate rocks have been thermally and metasomatically altered to mar- ble and tactite for as much as 1,500 feet from the contact with the stock, although minor discontinuous metasomatic effects are noted in all rocks out to 3,000 feet. Pyroclastic rocks of the Oak Spring formation (Miocene(?) or younger) unconformably overlie parts of the stock and Paleozoic formations (Houser and Poole, 1960a, 1960b). The granodiorite intrusive is light gray to green- ish medium gray, equigranular, and predominantly medium grained (Houser and Poole, 1959). Its aver- age composition, based on 19 modal analyses, is 28 [percent quartz, 16 percent potassium feldspar, 45 percent plagioclase, and 9 percent biotite. The aver- age grain size is about 2 mm, but the common range is 1/2 to 4 mm. The texture is granitic and very slightly porphyritic. No distinct inclusions of coun- try rock are known. The contact between granodiorite and adjoining quartz monzonite masses is generally vertical or very steep. In detail it is highly irregular and shows mutually penetrating fingers of each rock. These fingers are measurable in inches or feet in width and length. No glassy chilled zone has been noted in either rock. N0 systematic variation like that described for the quartz monzonite has been noted in the texture or composition of the granodiorite in relation to this contact. ' The quartz monzonite intrusive is concluded to be younger than the granodiorite because of a transi— tional variation in texture and composition of the quartz monzonite inward from its contact with the granodiorite, and because similar transitions are found in the quartz monzonite where it intrudes the Pogonip group. The quartz monzonite intrusive can be divided on the basis of grain size into a fine-grained variety, in which the average subhedral grains are from 14 to 1 mm across, and a medium-grained variety in which they are from 1 to 11/2 mm across. Fine- grained quartz monzonite occurs in a zone that parallels the border of the intrusive; the medium- grained variety makes up the remainder of the in- trusive. The peripheral zone of fine-grained rock is from 50 to 800 feet wide; it averages 500 feet wide where the intrusive adjoins the granodiorite, and less than 100 feet wide Where it adjoins the marble. In most places the fine-grained rock grades to the medium-grained variety within distances ranging from a few feet to 100 feet. In some places the two varieties are intimately intermixed; this is thought to be the result of autointrusion of older fine-grained material by younger medium-grained material. Where in contact with the granodiorite intrusive, the quartz monzonite intrusive varies in composi- tion from quartz diorite in the first 15 feet to grano- diorite throughout the next 45 feet, and to quartz monzonite in the remainder of the mass. However, the zones vary considerably in width from place to place, and the boundaries are indefinite. Table 1 shows the mineralogic variations. The fine-grained border zone of the quartz mon- zonite next to the marble is texturally similar to corresponding zones in the quartz monzonite next to the granodiorite although it is more highly va- riable mineralogically and chemically. Autointru- sion similar to that observed in the vicinity of the contact with the granodiorite is also common near the contact with the marble. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—177 TABLE 1.—Changes in the essential mineral compositions, in volume percent, of the quartz monzonite intrusive at selected ' intervals from the contact with. the granodiorite intrusives [tr, trace] Volume percent Distance from Estimated volume Potassium Rock Interval granodiorite percent of quartz Number of . . ‘ . Total feldspar type intrusive monzonite modal Quartz Potassmm Plagioclase Biotite Hornblende Total feldspar of total (feet) intrusive 1 analyses feldspar 2 feldspar 1 ....... 15 and less.. 08 9 22 8 54 15 tr 99 62 13 Quartz diorite 2 ....... 15—60 ...... 2.2 5 27 17 46 8 tr 98 63 27 Granodiorite _ 3 ....... 60—200 iiiii 7 4 26 25 42 7 O 100 67 37 . 4 Quartz monzonite 4 ....... >200 ...... 90 7 28 25 40 6 tr 99 65 38. 5 D0. Weighted average ........ 28 25 40 6 tr ...... 65 38.5 composition3 1 Based on the total exposed quartz monzonite stock. 2 Includes proportioned amounts of potassium feldspar phenocrysts. 3 Weighted for the various proportions of the intrusive represented in intervals 1 through 4. The relative ages of the quartz monzonite and granodiorite are important in interpreting the lead- alpha age determination for the Climax stock. It has been concluded that the quartz monzonite is the younger intrusion, and because the lead-alpha age was determined for this intrusive, it applies as the youngest age limit for the intrusion of the preceding granodiorite. . Field relations indicate that the Climax stock was intruded no earlier than Permian(?) time. Strata of the Tippipah limestone of Permian( ?) and Penn- sylvanian age 10 miles to the southwest are without noticeable breaks in sedimentation and are without coarse clastics that would suggest nearby contem- poraneous or previous structural deformation (P. P. Orkild, oral communication, 1960) such as the tight folding and high-angle faulting which next to the Climax stock (Houser and Poole, 1960a) pre- ceded intrusion. Many of the metamorphic effects equivalent to those observed next to the stock are found throughout the formations of Ordovician through Mississippian age that had been involved in this deformation. The field relations also indicate that the stock was intruded, exposed, and dissected before deposi- tion of the Oak Spring formation, which is of Ter- tiary age, possibly Miocene or Pliocene (Johnson and Hibbard, 1957, p. 369). Two lead-alpha age determinations made by T. W. Stern (written communication, 1960) for zircon from the medium-grained quartz monzonite give estimates of 330 i 35 and 230 i 25 million years. The younger of these two estimates is thought to be more nearly correct because it was substantiated by replicate determinations and it falls within the age limits established by field relations. Therefore, both intrusions of the Climax stock are dated tentatively as Permian(?) to early Mesozoic. REFERENCES Houser, F. N., and Poole, F. G., 1959, “Granite” exploration hole, Area 15, Nevada Test Site, Nye County, Nev.— interim report, Pt. A, Structural, petrographic, and chemical data: U.S. Geol. Survey TEM~836, open-file report. 1960a, Preliminary geologic map of the Climax stock and vicinity, Nye County, Nev.: U.S. Geol. Survey Misc. Geol. InV. Map I—328. 1960b, Structural features of pyroclastic rocks of the Oak Spring formation at the Nevada Test Site, Nye County, Nev., as related to the topography of the under- lying surface, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400—B, p. B266—B268. Johnson, M. S., and Hibbard, D. E., 1957, Geology of the Atomic Energy Commission Nevada Proving Grounds area, Nev.: U.S. Geol. Survey Bull. 1021—K, p. 333—384. ’5? B—178 GEOLOGICAL SURVEY RESEARCH 1961 74. RHYOLITES IN THE EGAN RANGE SOUTH OF ELY, NEVADA By DANIEL R. SHAWE, Denver, Colo. Rhyolite of Tertiary age in the Egan range south of Ely, White Pine County, Nev., occurs as (a) in- trusive bodies, including a volcanic neck a mile across and a small sill; and (b) extensive dissected layers of welded tuff (fig. 74.1). Whether the in- trusive rhyolite bodies are comagmatic with and mark the vents for the welded tuif ash flows is the subject of this paper. This possibility is in part suggested by the crude tendency for the welded tuff layers to dip outward from the neck (fig. 74.1), and in part by the superficial similarity of the rhyolites. PETROLOGIC CHARACTER OF THE RHYOLITES The intrusive rhyolite is generally a light- to dark- gray porphyritic rock composed of phenocrysts mostly about 1 to 2 mm across set in an aphanitic or glassy matrix that makes up about 75 to 80 per- cent of the rock. Glassy rhyolite forms a chilled border 100 to 200 feet wide around the volcanic neck. Flow structure is locally evident, generally as vertical banding in the volcanic neck and linea- tion in the sill. Much of the rhyolite in the neck is brecciated, and, as seen in thin section, flow lines are marked by strings of crushed crystals embedded in groundmass (fig. 74.2). Apparently deuteric or hy- drothermal alteration affected large parts of the volcanic neck, as these parts are bleached light yel- lowish gray to almost white, and the rhyolite has become “porcelaneous.” Another result of deuteric or hydrothermal action in the volcanic neck was the development of numerous small and imperfect "thunder-eggs”—cavities within dense, siliceous el- lipsoidal shells lined with chalcedony and minor amounts of fluorite and manganese oxide. Oxidation occurred locally in the neck, as parts of the rhyolite are pinkish from “dusty” hematite. Small inclu- sions of chert or silicified limestone 1 mm to 1 cm in diameter are abundant. Phenocrysts in intrusive rhyolite comprise sub- equal amounts of quartz, sanidine, and plagioclase (albite to oligoclase?), and about 1 percent of bio- tite; the size range is about 0.1 to 4 mm. Quartz occurs as euhedral to strongly corroded and embayed crystals; some is smoky. Sanidine forms subhedral to euhedral crystals; a few crystals contain inter- grown quartz in graphic and myrmeckitic forms (fig. 74.3). Plagioclase forms subhedral to euhedral crystals, with slight oscillatory zoning and few al- bite and pericline twins. Biotite is dark brown to light yellowish brown and in places is charged with tiny specks of an iron oxide. Except for sparse iron ores, no accessory minerals were recognized. The welded rhyolite tuff is similar in gross ap- pearance to the intrusive rhyolite, except that al- most everywhere it shows layering due to flattened pumice lapilli, and there is no obvious flow structure. Phenocrysts are mostly 1 to 2 mm across and are em- bedded in a glassy matrix constituting about 50 to 65 percent of the rock. In hand specimen, the tuffs appear no darker than the intrusive rhyolites, although crystals, especially mafic species, are more abundant in the welded tuffs. Inclusions of chert or silicified limestone in the welded rhyolite tuff appear to be more abundant than in the intrusive rhyolite, and they are not concentrated locally—as they are in the intrusive rock. Phenocrysts in welded tuff comprise plagioclase (albite to andesine?), making up about 15 percent of the rock, lesser and subequal amounts of quartz, sanidine, and biotite, about 1 percent of pyroxene, iron ores, and pale hornblende, and traces of sphene, apatite, and zircon. The size range of all pheno- crysts is about 0.1 to 4 mm. Plagioclase occurs as subhedral to euhedral crystals with slight to rather strong progressive zoning; a few crystals show ragged cores that are probably albite, rimmed with andesine(?) which is zoned outward progressively to albite. Albite and pericline twins are sharper and more abundant than in plagioclase of the intrusive rhyolite. Quartz is euhedral to strongly corroded and embayed (fig. 74.4) ; hand specimens show some smoky quartz like those of the intrusive rhyolite. Sanidine forms subhedral to euhedral crystals; a few of these have glass inclusions, in part zoned, but none contain graphic and myrmeckitic intergrowths of quartz. Biotite is strongly pleochroic, almost black to yellowish brown with a greenish cast, and com- monly includes minute apatite crystals, and opaque iron minerals along cleavage traces. Accessory min- erals aggregate less than 1 percent of the rock; they comprise iron ores, sphene (some diamond-shaped grains as much as 0.5 mm long), apatite, and zircon. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—179 115°00’ 114°45’ 39°15' 39°00’ — 38°45’ VALLEY STEPTO E 700 fl EXPLANATION ”7/2 \ LJ Outline of area of rhyolite Crosshatched area is volcanic neck. (Not all rhyolite areas are shown) \15 Strike and dio of layering in rhyolite \ I5 \\ Estimated strike and dip of layering in rhyolite 0/ 4 Sample locality 7 is about 50ft stratigraphically below 5; 3 is afew ft from the wall ofthe volcanic neck, 4 is about 100ft, and 2 is about 200ft ; 1 is in the sill NEVADA FIGURE 74.1.—Map showing areas of rhyolite and sample localities in the Egan range south of Ely, Nev. .B—180 ' GEOLOGICAL SURVEY RESEARCH 1961 TABLE 1.—Chemical analyses and semiquantitative spectrographic analyses of eight rhyolites from the Egan range south of Ely, Nevada [Chemical analyses by Margaret Lemon; semiquantitative spectrographic analyses by Paul R. Barnett; d, detected; 0, looked for but not found (below limit of detectability)] - Intrusive rhyolite ' ' Extrusive rhyol'ite Sill Volcanic neck Arithmetic Arithmetic Welded tufl’ average of “Compari- average of _ _ ...#_ four intrusive son four extrusive Sample rhyolites factor" rhyolites Sample 1 2 3 4 5 6 7 8 (DRS—45—58) (DRS—22—58) (DRS‘21—58) (DRS—52—58) (AB—23—5I) (DRS—5—59) (AB—22—58) (DRS—28—58) Chemical analyses SiOz ........ 75.36 73.09 72.92 72.49 73.47 > 69.71 70.50 70.28 69.46 68.58 A1203 ....... 13.55 13.59 13.63 13.45 13.56 < 14.11 14.31 13.97 14.62 13.55 Fe203 ....... .31 .44 .51 .55 .45 <2X 1.12 1.07 1.09 1.11 1.21 FeO ........ 43 34 .27 .25 .32 <4X 1.41 1.41 1.63 1 44 1.16 MgO 07 O7 .14 .08 .09 <9X .81 .74 .76 .84 .88 CaO ........ 84 .90 .97 .88 .90 <3X 2.85 2.89 3.21 2.98 2.30 Na20 ....... 3 80 3.42 3.48 3.30 3.50 > 2.51 3.02 2.48 2 97 1.56 K20 ........ 4 61 5.11 4.83 5.00 4.89 > 3.84 3.48 3.70 3.54 4.64 H20+ ...... 35 2.46 2.66 3.33 2.20 > 1.81 1.43 1.38 1.53 2.88 20— ...... 19 12 .29 .23 .21 <5X 1.00 .36 .50 61 2.52 T102 ....... 05 05 05 .05 .05 <9X 45 46 45 47 . 43 P205 ........ 09 01 01 .00 .03 <3X 10 10 09 10 09 MnO ....... 07 08 07 .08 . 08 > 05 05 04 05 04 C02 ........ 01 01 01 01 .01 <2X 02 01 03 03 00 Cl .......... 01 03 03 02 .02 ‘ = 02 04 01 04 00 F ........... 11 14 11 13 12 >2X 07 08 03 09 07 Sub-total. . 99.85 99.86 99.98 99.85 ............................ 99.95 99.65 99.88 99.91 Less 0.... .05 .07 .06 .05 ............................ .04 .01 .05 .03 Total ..... 99.80 99.79 99.92 99.80 ............................ 99.91 99.64 99.83 99.88 Semiquantitative spectrographic analyses 1 B.......... 0 .0015 .0015 .0015 .0011 > 0 0 0 0 0 Ba.......... .003 .003 .003 .003 .003 <60X 7.19 .15 .3 .15 .15 Be. . . . . . . . . . .0003 .0003 .0003 .0003 .0003 >2X .00015 .00015 .00015 .00015 .00015 Ce .......... 0 0 0 0 0 < .023 .015 .03 .03 .015 C0 .......... 0 0 0 0 0 < .0003 . 0003 . 0003 .0003 . 0003 Cr .......... d d .0003 d < .0003 < .0003 .00015 .0007 .0003 .00015 Cu ......... .0003 d d d < .0003 < .0003 .0003 .0003 .0003 .0003 Ga ......... .003 .003 . 0015 .0015 .0023 > 3X . 0009 .0007 .0007 . 0015 .0007 La.......... 0 0 0 O 0 < .011 .007 .015 .015 .007 Nb ......... .003 .003 .003 .003 .003 > .0019 .003 .0015 .0015 .0015 , Nd ......... 0 0 0 0 0 < .009 .007 .015 .007 .007 Ni .......... 0 0 0 0 0 < < .0003 .0003 .0003 0 0 Pb .......... .003 .003 .003 .003 .003 > 3X .0009 .0007 .0007 . 0015 .0007 Sc .......... . 0003 . 0003 . 0003 . 0003 . 000 < 2X . 0007 . 0007 . 0007 . 0007 . 0007 Sn .......... . 0007 .0007 . 0007 . 0007 . 0007 > 0 0 0 0 0 Sr .......... .003 .003 .003 .003 .003 <20X .06 .07 .07 .07 .03 V.......... 0 0 0 0 0 < .004 .003 .003 .007 .003 Y .......... .003 .003 . 003 .003 .003 > .0023 .003 . 0015 .003 . 0015 Yb ......... . 0003 .0003 .0003 .0003 . 0003 > . 00023 . 0003 . 00015 . 0003 . 00015 Zr .......... .007 .007 .003 .003 .005 <4X .019 .015 .03 .015 .015 1 Figures are reported 'to the nearest number in the series 7, 3, 1.5, 0.7, 0.3, 0.15, etc., in percent. These numbers represent midpoints of group data on a geometric scale. Comparisons of this type of semiquantitative results with data obtained by quantitative methods, either chemical or spectrographic, show that the assigned group includes the quantitative value about 60 percent of the time. SHORT PAPERS INVTHE GEOLOGIC AND CHEMICAL CHARACTER OF} THE RHYOLITES The chemical character of four samples of intru- sive rhyolite and four samples of welded rhyolite Sanidine Glass B m ore Biotite 1 MILLIMETER 9“] FIGURE 74.2.——Pen-and-ink drawing of rhyolite from volcanic neck. Glass A is clear; glass B is comminuted containing numerous small fragments of broken crystals (sample 3). Quartz 1 MILLIMETER l—____J FIGURE 74.3.—Feldspar crystals with myrmeckitic and graphic intergrowths of quartz. Feldspar crystal A is sanidine from sill (sample 1). Feldspar crystal B is sanidine rimmed with plagioclase from volcanic neck (sample 4). B—181 tuff is summarized in table 1. As shown in table 1, the four intrusive rhyolites form a group closely similar in composition, as do the four welded tufi's; the two groups are, however, chemically quite dis- tinct. (See “Comparison factor” of the group aver- ages, table 1.) For more valid comparison of the groups the analyses should probably be recalculated without H20, although this could not alter the basic differences between the two. HYDROLOGIC SCIENCES, ARTICLES 1-146 CONCLUSIONS Both the petrologic and chemical data suggest that the intrusive and extrusive rhyolites were not closely related genetically. For example, the dis- tinct differences between both plagioclase and sani- dine phenocrysts in the two groups indicate that they probably were not derived from the same magma chamber, even at widely separated times. Further, the obvious chemical disparity between the intrusive rhyolite and the welded rhyolite tuff suggests that one is not related to the other through crystal frac- tionation. 1 MILLIMETER |—___l FIGURE 74.4.—Pen-and-ink drawing of welded rhyolite tuff. Glass A generally rims crystals, is vesiculated and frag- mented; glass B forms matrix enclosing whole and broken crystals and particles of glass A (sample 8). ’X B—182 GEOLOGICAL SURVEY RESEARCH 1961 75. TECTONIC SIGNIFICANCE OF RADIAL PROFILES OF ALLUVIAL FANS IN WESTERN FRESNO COUNTY, CALIFORNIA By WILLIAM B. BULL, Sacramento, California Work done in cooperation with the California Department of Water Resources The shape of an alluvial fan reflects part of its depositional history, which is controlled primarily by erosional and tectonic changes in the drainage basin upstream. The radial profiles of fans along the western border of the San Joaquin Valley in western Fresno County, Calif, are interesting fea- tures because they are segmented, and because they can be used to help decipher part of the tectonic history of the area. The drainage basins of the fans head in two dis— tinct mountainous areas. The small fans have drain- age basins with ephemeral streams which head in the foothill belt of the Diablo Range. The large fans have drainage basins with intermittent streams which head in the main Diablo Range. The overall radial profiles of the alluvial fans are concave upward, but the slope does not decrease at a uniform rate away from the mountain front. Instead the radial profiles are segmented. Profiles of fans whose streams head in the foothill belt have three straight—line segments; profiles of fans whose streams head in the main Diablo Range have four segments: three are straight lines but the uppermost segment may be concave upward. An example of each type of radial profile is shown in figure 75.1. The dots represent altitudes from topographic maps that have a 5-foot contour interval. The lengths of the segments and the angular relationships between them vary for different fans, but the profiles of adjacent fans generally are similar. Near their apexes the fans accumulate deposits that have the same general slope as the valley up- stream from the fan. Slope measurements from topographic maps of 10 streams show that the upper- most fan segments and the valleys upstream from the fans for a distance of 1/2 to 1 mile have the same general slope, although there have been periods of arroyo cutting during the last century. Five of these valleys have slightly lower gradients than their up- permost fan segments, and five have slightly higher gradients. For one stream, the slope of a terrace for ‘ three-fourths of a mile upstream from the fan is the same as the upper fan segment. The continuous slope implies that the terrace deposits were laid down at the same time as the upper deposits of the fan segment. Valleys also tend to be cut down to the same gradient as the adjacent lower fan surface. This tendency is illustrated by the stream of Tumey Gulch where it is entrenched into the upper fan segment. More than a mile of the stream has been cut down to the same gradient as the adjacent lower fan segment. Channel trenching helps preserve fan segmenta- tion by restricting deposition to certain fan seg- ments. At the present time deposition is not oc— curring on the upper fan segment of the fans whose streams head in the foothill belt, or on the upper two segments of the fans Whose streams head in the main Diablo Range. Climatic fluctuations, uplift of the mountains, and changes in base level should be considered as pos- sible causes of fan segmentation. Neither the fans nor drainage basins show any evidence of marked base-level changes. Moisture studies of deep cores from the dry alluvial-fan deposits do not indicate major changes in rainfall or stream runoff. How- ever, Pliocene and Pleistocene deposits on the sum— mits of the foothill belt show that parts of the mountains were uplifted more than 2,000 feet during Pleistocene time. The uplift occurred mainly as monoclinal and anticlinal folding. The drainage basins of western Fresno County have paired terraces that are commonly 100 to 300 feet above the present—day stream channels. These terraces represent periods of lateral planation and little downcutting followed by periods of accele- rated downcutting, which made narrower valleys within the former wider valleys. The accelerated downcutting accompanies uplift in the mountain area, which steepens the stream gradient; as a re- sult, the fan deposits also should have a steeper gradient. Thus, the result of uplift would be a “new fan” built out onto the older more gently sloping fan. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—183 I SCALE, IN MILES 0 3 6 9 12 I I I I I l I I I I I — \\ 500 _ CANTUA CREEK FAN _ \ (Main Diablo Range) \ \ J 700 \ \\ r r \Y 400 L? \ VERTICAL EXAGGERATION x 211 _ E Lu \ L|J u— 600 u. E — E g _ . _ I; 3 I— l: \ l: '3 TUMEY GULCH FAN \ 300 2‘ < 500 , (Foothlll belt) _ 400 VERTICAL EXAGGERATION x 53 200 300 I l | 4 6 SCALE, IN MILES FIGURE 75.1.—Radial profiles of two alluvial fans in western Fresno County, Calif. Some stages of alluvial-fan development are out- lined by diagrams in figure 75.2. In figure 752a a fan and stream channel have developed a common gradient. Uplift steepens the stream gradient and the new fan deposits also have a steeper gradient (fig. 75.2b). The stream-channel gradient may have been steeper after the uplift, but the slopes in figure 75.2b represent equilibrium conditions near the end of the stage. Another period of uplift makes the youngest segment (fig. 75.2c), completing a fan simi- lar to the Tumey Gulch fan (fig. 75.1). Deposition continues on the fan and the stream channel main- tains the same slope as the fan by aggrading slightly (fig. 75.2d). An increase in the amount and intensity of rainfall causes temporary channel trenching (fig. 75.2e). The low terrace and the upper fan segment have the same slope, and the downstream end of the entrenched channel has the same gradient as the adjacent lower segment. The surficial deposits of respective fan segments generally are not of dis- tinctly different ages. For example, deposition may, have been occurring mainly on the upper segment a century ago, but channel trenching then caused de- position to occur mainly on the middle segment as the end of the channel moved downslope (fig. 7 5.2e). Thus, in the situation illustrated in ~ figure 75.2e, deposition is restricted to the area downslope from the upper two fan segments, as it is for the streams that head in the main Diablo Range. The segmented fans of western Fresno County indicate three or four episodes of uplift of the Coast Ranges rather than continuous uplift. Part of the uplift may have occurred in the last 3,000 years. Charcoal that was 10.5 feet below the surface of the upper (youngest) fan segment of the Arroyo Hondo fan is 1,040 i 200 years old according to a radiocarbon age determination.1 The total thickness of deposits of the fan segment at this locality is 1 Radiocarbon age determination made by Meyer Rubin of the US. Geo- logical Survey; sample W493. B-184 estimated to be 24 feet, which suggests that the segment is 2,000 to 3,000 years old, if a similar rate of deposition existed throughout its history. Segmented fans apparently occur where the slope of the valley upstream from the apex has been made steeper than the slope of the fan. Large changes in fan slope probably indicate greater uplift and steep- ening of the valley upstream from the apex than do small changes in fan slope. The different radial profiles of fans whose streams head in the foothill belt for 50 miles along the western border of the San Joaquin Valley indicate different amounts or times of uplift and rates of erosion in their drainage basins. The fans of streams that head in the foothill belt and main Diablo Range have a distinctive segmen- tation which reveals part of the tectonic history of their respective mountain areas. Fan segmentation should be helpful in deciphering part of the tectonic history of the drainage basins of other mountain ranges. 76. GEOLOGICAL SURVEY RESEARCH 1961 Youngest deposits Mountains Terrace Stream channel \'- Youngest deposits '\ Stream channel e FIGURE 75.2.—Diagrammatic sketches showing segmented alluvial fan development in western Fresno County, Calif. 6h SOIL-MOISTURE STORAGE CHARACTERISTICS AND INFILTRATION RATES AS INDICATED BY ANNUAL GRASSLANDS NEAR PALO ALTO, CALIFORNIA By F. A. BRANSON, R. F. MILLER, One of the chief determinants of the kinds and amounts of vegetation found on unplowed land sur- faces is quantity of water stored in the soil and avail- able for plant growth during the growing season. The annual—grasslands floral assemblage of Califor- nia, although composed largely of introduced species, shows some striking contrasts on soils having dif- ferent water-storage capacities. Certain indicator plants have been identified that may help in mapping and I. S. MCQUEEN, Denver, Colo. soils of different textures, and in estimating quickly the hydrologic characteristics of soils in some local areas. The vegetation and soils of three small basins (310, 245, and 170 acres) near Palo Alto were mapped and sampled in 1959. A metal frame of the type shown in figure 76.1 was used to measure the amounts and kinds of vegetation. Sampling loca- tions were chosen at intervals along transects across SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 FIGURE 76.1.—Metal frame and pins used to measure amounts and kinds of herbaceous vegetation. each basin. The annual precipitation on the basins is about 22 inches, most of it falling at moderate intensities from November to March. The abundance, and commonly the kinds, of plants differed on the sandy and clayey soils in all three basins as shown on table 1. Most of the soils of the three basins were either sandy or clayey, generally with sharp boundaries between soil types, leaving only small areas of medium-textured soils. Because the medium-textured soils were so limited, only the vegetation and soil analyses of the sandy and clayey soils were studied in detail. Most of the soils de- veloped in place on bedrock consisting of alternate shale and sandstone strata that Branner and others (1909) mapped as the Purisima formation of Ter- tiary age. Residual soils developed from these strata can be seen in figure 76.2. Species that were more abundant on clayey than on sandy soils included wild oat, Italian ryegrass, bellardia, tarweed, and bur clover. Purple star thistle was found only on clayey soils. Soil cracks were present only in the clayey soils. Four or more hits (contacts) in soil cracks per 100 pins were re— corded for clay soils of the three basins. B—185 Greater amounts of vegetation and a greater va- riety of plant species grow on the sandy soils. Spe- cies present in most samples but more abundant on sandy soils included shoft chess and red-stem filaree. Species found only on the sandy soils were ripgut brome, California oatgrass, foxtail fescue, mouse barley, needlegrass, agoseris, bindweed, Spanish clover, two species of lupine, California poppy, and fiddle dock. Sandy soils were characterized by a greater number of vegetation contacts per 100 pins, more mulch, and less bare soil surface. Trees and shrubs were widely but uniformly spaced in the three basins except forythe few dense groves on north-facing slopes. The three important tree species in order of their abundance were valley oak (Quercus lobata), blue oak (Q. douglasii), and coast live oak (Q. agrifolia). The trees and shrubs did not appear to be affected by the different soil textures. Some of the physical characteristics of the sandy and clayey soils of the basins studied are shown in table 2. The percent moisture at saturation and at field capacity were considerably greater in the clayey than in the sandy soil. The estimated field capacity in the clay soil was approximately double that of the sandy soil in the upper 2 feet of the two soils. Linea] shrinkage was nearly four times greater for the clayey than for the sandy soils. I, . ..,,~‘~;fi,%, FIGURE 76.2.—Residual soils developed on alternating strata of the Purisma formation. Sandstone is on the right and shale is on the left. B—186 TABLE 1.—Herbaceous vegetation on basins A, B, and C near Palo Alto, Calif. [Numbers are average hits per 100 pins, using device shown on figure 76.] Basin and type of soil A B C Sandy Clayey Sandy Clayey Sandy Clayey Grasses Aveua fatua L. Wild oat .............. 4.7 Bromus mollis L. Soft chess ............. 53 .0 Bromus rigidus Roth. Ripgut hrome ......... 1 .3 Danthonia cali/arniea Boland California ontgrass ............. 1 .0 Festuca megalura Nutt. Foxtail fescue ....................... 17.9 Hordeum gussonianum Par]. Mediterranian barley. . . Hordeum murinum L. Mouse barley ....................... Lalium multiflorum La In. Italian ryegrass ........ 17.7 Stipa cernua Stibbins and Love Needlegrass ........... 1 .0 Agoseris grandi flora (Nutt.) Greene Agoseris ..................... Bellardia tn'zago (L.) All. Bellardia .............. 0.7 2.2 Centaurea calcitrapa L. Purple star thistle ...... Convolvulus arvmsis L. Bindweed ........................... .4 Erodium cimtarium L 'Her. Red-stem filaree llllllll 44.7 35.5 53.6 Eschscholtzia californica Cham. California poppy ............................ , . . . . . . 1 .5 Lotus americanus (Nutt.) Bisch. Spanish clover ......... Lupinus bicolor Lindl. Lupine ................ Lupinus formosus Greene Lupine ....................... Madia sp. M01. Tarweed .............. 3.7 12.0 6.9 8.5 1.2 .WIedicaga hispida Gaertn. Bur clover ............. 5.3 3.5 9.0 11.5 2.2 Rumez pulcher L. Fiddledock............ Unidentified forbs .......... Vegetation contacts per 100 pins1 ........ Other Nlulch ................ 98.7 93.3 103.8 107.0 121.8 110.0 Bare ...................... 3 0 13.2 .5 5.5 ....... 4.7 Soil cracks ......................... 4.4 ....... 4 .0 ....... 4.7 1 Total of grasses and forbs. Although the soil moisture retention capabilities of the clayey soils exceeded those of the sandy soils, more herbaceous vegetation grew on the sandy soils, GEOLOGICAL SURVEY RESEARCH 1961 probably because of higher rates of infiltration of water, and because soil water is more readily avail- able for plant use in the sandy soils. Infiltration rates of 1.35 to 13.85 inches per hour with a mean of 6.40 inches for 6 l-hour runs were measured for the sandy soils. The infiltration rate on an un- cracked clay—loam soil was 0.18 inch per hour; how- ever, the degree of soil cracking (shrinkage, table 2) and an almost complete absence of soil erosion, even on slopes exceeding 40 percent, indicated that moisture entered the clayey soils fairly readily. The cracks provide large areas for water entry until they are closed by swelling of the moistened clays. TABLE 2.—Some characteristics of a sandy soil and a cla‘yey soil in the basins studied Depth Moisture Estimated _ from soil at field Lineal surface saturation 1 capacity 2 Sand 3 Silt 3 Clay 3 shrinkage ‘ (inches) (percent) (percent) (percent) (percent) (percent) (percent) Sandy soil 24.0 12 0 54 30 16 4.7 25.2 12 6 55 31 14 5.6 23.6 11 8 55 30 15 5.0 24.8 12 4 56 26 1‘8 4.8 31.0 15 5 49 32 19 8.0 26.8 13 4 44 43 13 4.3 Clayey soil 0 — 4 ....... 50.8 25.4 19 33 48 19 2 4 - 7.. 49.7 24.8 17 23 60 19 8 7 — 10 ....... 48.4 24.2 17 31 52 19 6 10 — 13 ....... 48.6 24.3 16 34 50 19 0 13 — 16 ....... 48.8 24.4 20 31 49 19 0 16 — 19 ....... 48.6 24.3 18 32 50 18 6 19 — 23 ....... 49.1 24.6 20 32 48 18 7 23 —- 26 ....... 46.6 23.3 21 31 48 18 4 26 — 30 ....... 46.6 23.3 26 27 47 21 1 30 - 34 ....... 42.1 21.1 28 35 37 19 5 3-1 — 38 ....... 32.8 16.4 40 29 31 113 38 — 42 ....... 23.4 11,7 56 27 17 8 (I 42 — 46 ....... 21.2 10 6 61 32 7 4 7 46 — 51 ....... 21.2 10 6 65 30 5 5 2 1 Method 273. (U.S. Salinity Laboratory Staff, 1954) . 2 One-half of percent moisture at saturation is shown as estimated field capacity. 3 The sand fraction (greater than 74 microns) was determined by sieving, the silt (2 to 74 microns) and clay (less than 2 microns) fractions by hy- drometer analyses. 4 Lineal shrinkage : 100 ( 1 — \3/ 100 Volume change + 100 ) REFERENCES Branner, J. C., Newson, J. F., and Arnold, Ralph, 1909, Description of the Santa Cruz quadrangle [California]: U.S. Geol. Survey Geol. Atlas, Folio 163. US. Salinity Laboratory Staff, 1954, Diagnosis and improve- ment of saline and alkali soils: U.S. Dept. Agriculture, Agr. Handb. no. 60, 160 p. ’>Z‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—187 \_ r v , p. . ,rx ..\,, "a 77. CAUSES AND MECHANICS 0F NEAR-SURFACE SUBSIDENCE IN WESTERN FRESNO COUNTY, CALIFORNIA By WILLIAM B. BULL, Sacramento, Calif. Work done in cooperation with the California Department of Water Resources Near-surface subsidence on certain alluvial fans in western Fresno County, Calif, has destroyed or damaged ditches, canals, roads, pipelines, electric transmission towers, and buildings, and has made the irrigation of crops diflicult. About 72 square miles have subsided and about 37 additional square miles probably would subside if irrigated. Three to 5 feet' of subsidence is common, and more than 10' feet has occurred within small areas. The subsidence results chiefly from the compaction of deposits by an overburden load as the clay bond supporting the voids is weakened by water percolat- ing through the deposits for the first time. The amount of subsidence that Occurs when water is applied is dependent mainly on the overburden load, natural moisture conditions, and the amount and type of clay. The materials are deposited during the winters as mud-flows, water-laid sediments, and deposits inter- mediate between these two types. Some of the voids commonly found in these alluvial-fan deposits are openings between grains held in place by a dry clay bond, bubble cavities formed by air entrapped at the time of deposition, interlaminar openings in thinly laminated sediments, buried (but unfilled) polygonal cracks, and voids left by entrapped vege- tation. An unusually large number of bubble cavi- ties is shown in the clay in figure 77.1. The average annual rainfall on the fans is only 6 to 8 inches. Plants and air remove much of the soil moisture during the hot, dry summers, reducing the moisture condition of the deposits to the wilting coefficient. Water from succeeding winter rains and floods does not percolate below the root zone; there- fore the deposits continue to be moisture deficient after burial below the root zone. Near-surface subsidence illustrates the signifi- cance of water in the natural compaction of sedi- ments. Most alluvial sediments are compacted in the presence of excess water as the overburden load increases. However, on the fans susceptible to near- surface subsidence, the deposits are moisture defi- cient and only part of the compaction occurs as the overburden load is gradually increased. Later ap- plication of irrigation water allows the compaction to increase suddenly to the normal amount of com- paction for a given overburden load, causing surface subsidence. EFFECT OF OVERBURDEN LOAD The amount of compaction due to wetting in- creases with an increase in overburden load, but most subsidence has been caused by compaction in the upper 200 feet of deposits. The surface of three irrigated test plots rose slightly immediately after the water was applied because the surface deposits swelled. When the water reached a depth of a few feet, the increased overburden load caused a net reduction in the volume of the deposits as the clay became wetter and lost part of its strength. The effect of the overburden load on subsidence during the first 42 months of operation of Inter- Agency test plot B (Inter-Agency Committee, 1958, p. 61—67) is shown in figure 77.2. Bench marks were set within cased holes drilled beneath this test plot at depths of 25, 50, 75, 100, 150, and 300 feet. The amount of compaction Within each depth interval above 150 feet was determined from periodic level- - FIGURE 77.1.—Bubble cavities in clay. B—188 PERCENT COMPACTION 0 2 4 6 8 10 12 0 I I I I I I I I I I I I 20 l\\ — \ _ 4o— 60— 80— DEPTH, IN FEET 100 120— 14O_lll‘lllilll~ FIGURE 77.2—Effect of overburden load on compaction due to wetting, Inter-Agency test plot B after 42 months of operation. ing of these bench marks. Each point in figure 77.2 represents the percent compaction within a 25-foot depth interval except the point at 125 feet which represents the 50-foot interval between 100 and 150 feet. To a depth of 100 feet, there is a nearly linear increase in the percent compaction with increasing depth. The reason for the decrease in the percent compaction of the 100- to 150-foot depth interval is discussed below. STRENGTH OF CLAY The strength due to clay in a deposit is dependent on the moisture content and on the type and amount of clay. These variables control the amount of com- paction due to wetting under a given overburden load. The strength of clay varies considerably for all moisture gradations between wet and dry. The natural moisture condition of the deposits susceptible to subsidence is about equivalent to the wilting co- efi'icient, and subsidence is chiefly the result of com- paction caused by increasing the moisture content of these deposits to a condition of field capacity. A good example of the importance of moisture conditions is provided by the compaction record shown in figure 77.2. Although the lithology does not appear to change with depth there is a marked change in the percent compaction in the zone be- tween 100 and 150 feet. The amount of compaction in this zone is only 7 percent, but the circle on the dashed (projected) line indicates that the amount of compaction for that overburden load should have been about 12 percent. Tests of cores showed a sharp increase in natural moisture Content below about 125 feet. The higher moisture content would indicate an increase in the natural compaction of GEOLOGICAL SURVEY RESEARCH 1961 the deposits below 125 feet, and therefore less com- paction due to artificial wetting. The effect of the amount of clay on compaction due to wetting is shown in figure 77.3. The consoli- dation tests were made on surface samples, there- fore a 50-foot overburden load was simulated. The variable of post—depositional environment was elimi- nated, because the air—dry Samples were collected a few months after they were deposited. The variable of textural features of the samples remains, but these features are controlled partly by clay content. Montmorillonite is the predominant clay mineral (R. H. Meade, written communication). This leaves the amount of clay as the most im- portant variable. The curve in figure 77.3 shows the amount of compaction that occurs when air-dry samples are wetted under load. The sample con- taining no clay did not compact when wetted. Sam- ples containing more than about 30 percent clay not only had enough strength to resist compaction when wetted but they showed a net swell under the simu- lated overburden load. The maximum compaction 14 12 EXPLANATION I Water-laid sediment '_ 10 A E I U 0 E Mudflow deposit a. E 8 t ‘ 3 Deposit intermediate between ; mudflow and water-laid types 5 l I g 6 E I ‘5 4i . o ‘ . z 9 4 °.\\ I— o < E \ I 8 2 . I +2 I I I I l ‘ I o 8 16 24 32 4o 48 CLAY CONTENT, IN PERCENT FIGURE 77.3.——Efl‘.‘ect of clay content on compaction due to wetting under a simulated load of 50 feet of overburden. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1—146 for the samples tested occurred when the clay con- tent was about 12 percent. If less than this amount is present, the dry overburden load already will have accomplished much of the compaction because there is not enough clay to preserve the larger voids. As the amount of clay increases above about 12 percent, the resistance of the sample to compaction when wetted increases progressively with clay con- tent. In addition, the montmorillonite clay minerals 78. B—189 ' swell. Both factors reduce the compaction progres- l l sively, and for the samples tested, the net compac- tion decreased to zero at about 30 percent clay. REFERENCE Inter-Agency Committee on Land Subsidence in the San Joaquin Valley,'1958, Progress report on land-subsidence investigations in the San Joaquin Valley, Ca1if., through 1957: Multilithed, 160 p., 45 pls. 6b SPECIFIC GRAVITY 0F SANDSTONES IN THE FRANCISCAN AND RELATED UPPER MESOZOIC FORMATIONS OF CALIFORNIA By WILLIAM P. IRWIN, Menlo Park, Calif. Work done in cooperation with the California Division of Mines The specific gravity of sandstone was investigated as an adjunct in distinguishing between the Fran- ciscan and related upper Mesozoic formations in the Coast Ranges and Sacramento Valley of California (fig. 78.1). In the Sacramento Valley the formations are of the shelf and slope facies, and constitute an essentially conformable sequence of strata that range in age from Late Jurassic to Late Cretaceous. For the purpose of this discussion the rocks of the Sacramento Valley sequence will be divided accord- ing to age into three units: the Knoxville formation of Late Jurassic age, the Lower Cretaceous, and the Upper Cretaceous. In the Coast Ranges most of the rocks of upper Mesozoic age are assigned to the Franciscan formation, a eugeosynclinal assemblage composed mostly of sandstone, but which includes approximately 10 percent greenstone and chert. The Franciscan also ranges in age from Late Jurassic to Late Cretaceous, and is more highly folded and faulted than the strata of the Sacramento Valley. The thickest section of the Sacramento Valley se- quence is about 35,000 feet, whereas the Franciscan formation probably is considerably thicker. Although the Franciscan is the dominant upper Mesozoic formation in the Coast Ranges, rocks of the Sacramento Valley sequence also are present, many as relatively small blocks folded and faulted into the Franciscan. Recognition of small structural blocks of strata of the Sacramento Valley sequence Within areas underlain chiefly by the Franciscan formation is difiicult in many places because com- pletely satisfactory criteria for distinguishing be- tween sandstones of the Sacramento Valley sequence and of the Franciscan formation have not been determined. The specific gravity of 1,030 specimens of sand- stone of both the Franciscan formation and the Sac- ramento Valley sequence was measured, including most of the specimens used by Bailey and Irwin (1959) for determination of K-feldspar content, and others collected throughout the Sacramento Valley and the northern and southern Coast Ranges. Spe- cific gravity was measured on a direct-reading bal- ance, with the specimen immersed in water. The average weight of the specimens is approximately 300 grams. Most of the specimens are essentially unweathered and impermeable, and for these the measurements represent bulk specific gravity. How- ever, many of the sandstone units of the Upper Cre- taceous of the Sacramento Valley sequence are per- meable, and as 'the surfaces of the specimens were not treated to prevent penetration by water, values somewhat higher than bulk specific gravity were obtained. . Cumulative frequency distribution curves based on the specific gravity measurements are shown in GEOLOGICAL SURVEY RESEARCH 1961 2.68 2.70 3.01 n n . 122° 100 -/—‘. x, |/\/\\ -.1\ 75 Upper Cretaceous 62 samples Lower Cretaceous 71 samples “a“ \ \_._ Knoxville formation 40 samples 50_.____ _...‘,TT.',',.iT‘ Franciscan formation CUMULATED FREQUENCY,IN PERCENT ‘ 857 samples l w“? o G _ l \Q“: Coastal belt l C" 128 samples _ ‘ .- q 4,, o ’ . . . . . . r 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 38°l a SPECIFIC GRAVITY 124° EXPLANATION Quaternary and Tertiary rocks zp'ovo‘ V .0.‘ _ - aw i l . p - . 4 . k...” - Marine sedimentary rocks Franciscan formation Undivided rocks \SheL/(md slope fuciea Eugeosynclmal fades of Coastal belt 1 v LATE JURASSIC TO LATE CRETACEOUS Granitic and Dre-Cretaceous meta< morphic rocks of the Klamath Mountains, NacimientOvSan An- dreas fault block, and Transverse Ranges ' o 100 MILES ‘b ~52; 53"“ N f- I Z ~ - ' . ~ _. < . Santa Barbara"\ ~ FIGURE 78.1'.—Map showing distribution of the Franciscan and related upper Mesozoic formations, with graph showing cumulative frequency distribution curves of specific 'gravity of sandstones. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 figure 78.1. The curve for sandstone in the Fran- ciscan formation is well separated from and on the high specific gravity side of the curves for the three units of the Sacramento Valley sequence. The median specific gravity of the sandstone in the Franciscan is 2.65. The marked increase in specific gravity at the upper end of the Franciscan curve reflects metamorphism of the sandstone that gen- erally is not recognized in hand specimen. E. H. Bailey of the Geological Survey studied the speci- mens that plot along this part of the curve and states (oral communication, January 1961) that most of the Franciscan sandstone with a specific gravity of 2.70, and all with a specific gravity of 2.71 or higher are metamorphosed; the metamor- phism is chiefly of the plagioclase feldspar to form jadeite and lawsonite. About 22 percent of the specimens of sandstone in the Franciscan have a specific gravity higher than 2.68, the highest ob- served in rocks of the Sacramento Valley sequence. The curves representing sandstone of the three units of the Sacramento Valley sequence are con- spicuously lower than the curve for the Franciscan formation and are displaced progressively toward the low specific gravity side of the graph with de- creasing age, although at some places the curves intermingle. As previously stated, many values for sandstone units of the Upper Cretaceous do not truly represent bulk specific gravity, and thus the curve for the Upper Cretaceous should be further to the left side of the graph than shown. Median values for the curves are 2.59 for the Knoxville formation, 2.57vfor the Lower Cretaceous, and 2.55 for the Upper Cretaceous. Reasons for the general differences in specific gravity of the sandstone of the several units are not surely known. However, one might speculate that the generally higher specific gravity of the sandstone in the Franciscan relative to the sand- stone of the Sacramento Valley sequence results B—191 from a greater abundance of mafic volcanic frag- ments (high specific gravity), a general lack of K- feldspar (low specific gravity), and a high degree of compaction. The progressive decrease in specific gravity with decrease in age of the units of the Sacramento Valley sequence probably is related to the marked increase in K-feldspar content with de- creasing age, and to a progressively smaller amount of compaction resulting from shallower depth of burial. Specific gravities of 128 specimens of sandstone from the coastal belt of undivided sandstone, shale, and conglomerate are shown by a separate curve. A general lack of volcanic rocks, sparse paleontologic data, and results of study of K-feldspar content (Bailey and Irwin, 1959), suggest an affinity with the Sacramento Valley sequence. The cumulative frequency distribution curve for sandstone of the coastal belt also suggests this aflinity, as it is close and generally parallel to the curves for the units of the Sacramento Valley sequence. Although gener- ally somewhat to the right of the curves for the units of the Sacramento Valley sequence, it is far to the left of the curve for the sandstone of the Franciscan. The generally higher specific gravity indicated by the curve for the coastal belt, compared to the curves for units of the Sacramento Valley sequence, may reflect the presence of areas of un- recognized sandstone of the Franciscan formation within the coastal belt. This interpretation is sup- ported by the presence of a few specimens with specific gravities above 2.68, which is higher than the specific gravity of any specimen collected from the Sacramento Valley sequence. REFERENCE Bailey, E. H., and Irwin, W. P., 1959, K-feldspar content of Jurassic and Cretaceous graywackes of northern Coast Ranges and Sacramento Valley, California: Am. Assoc. Petroleum Geologists Bull., v. 43, no. 12, p. 2797—2809. ’X‘ B—192 GEOLOGICAL SURVEY RESEARCH 1961 wh/Jé 79. SOME EXTREMES OF CLIMATE IN DEATH VALLEY, CALIFORNIA By T. W. ROBINSON and CHARLES B. HUNT, Menlo Park, Calif, and Denver, Colo. The hydrologic basin of Death Valley, Calif, in- cludes about 8,700 square miles, of which about 500 square miles is below sea level. The bottom of the basin, the salt pan, covers about 200 square miles and is more than 200 feet below sea level. Eleva- tions in Death Valley range from 282 feet below sea level near Badwater, the lowest point in the United States, to 11,045 feet at Telescope Peak some 15 - miles to the west. The climatic measurements made at the National Park Service Headquarters, 3 miles north of Fur- nace Creek Ranch, for the period May 1958 to May 1959, are shown in figure 79.1. The conditions of low humidity, high summer temperatures, high evaporation, and low rainfall, shown graphically in the figure, typify the climate of Death Valley. In the 48-year period, 1912 to 1960, the US. Weather Bureau at Furnace Creek Ranch, formerly Greenland Ranch, recorded the lowest average rain- fall, 1.66 inches, of any official weather station in the United States. The average monthly rainfall ranges from a high of 0.29 inch in February to a low of 0.02 inch in June. There have been periods of more than a year in which less than 1 inch of rain has fallen and, during 1929, no measurable rainfall was recorded at this station. The station, 168 feet below sea level, is located on the edge of the salt pan. A frequency analysis of the precipitation records shows an annual precipitation of less than 1 inch during 40 percent of the time, and 3 inches or less for 96 percent of the time. Rainfall has exceeded 4 inches only twice in 48 years. Temperatures greater than 120°F are common during the summer months. The highest air tem— perature ever measured in the shade at an official Weather Bureau station in the United States, 134°F, was recorded on July 10, 1913, at Greenland Ranch, now Furnace Creek Ranch. This recording is be- lieved to have been exceeded only by 136°F reading that was observed at Azizia, Tripolitania in north- ern Africa on September 13, 1922, and which is generally accepted as the highest air temperature recorded under standard conditions (Hansen, 1960, p. 442). July is the hottest month with a long-time average maximum of 116°F. However, Furnace Creek Ranch does not appear to be the hottest place in the valley. Temperature records indicate that Badwater, about 15 miles south of the ranch on the salt pan, 280 feet below sea level, has maximum tem- peratures as much as 3°F higher; the average maxi- mum for July was 122.5OF in 1959 and 120.4° in 1960, While at the ranch the average maximum was 119.3°F and 118.1OF. In July 1959, the highest tem- perature recorded at the ranch was 124°F, but at Badwater this temperature was exceeded on 11 days. Similarly in July 1960, 124°F was exceeded on only 1 day at the ranch but on 5 days at Badwater. Ground surface temperatures in excess of 160°F have been recorded in several parts of the valley. The maximum recorded was 1900F in August 1958, and was measured on the surface of massive gypsum at Tule Spring some 5 miles west of Badwater. The average relative humidity for 2 years of rec- ord at the National Park Service Headquarters, May 1, 1958 to May 1, 1960 was 17.2 percent. The aver- age maximum was 23.3 percent and the average minimum 11.7 percent. The highest recorded during this 2-year period was 74 percent and the lowest was 3 percent. The driest day was April 8, 1959 (see fig. 79.1), when the minimum was 4 percent and the maximum was 6 percent. Pan evaporation in the hydrologic basin of Death Valley is the highest in the nation, exceeding 120 inches a year in most of the basin. It is greatest in Death Valley proper. In the two 12-month periods of record, May 1, 1958 to May 1, 1960, for the standard Weather Bureau pan at the National Park Service Headquarters, the evaporation was 155.05 and 144.66 inches. So far as can be ascertained, this is the highest evaporation from a standard pan ever recorded in the United States. Monthly pan evaporation ranged from a high of 22.71 inches in July 1960 to a low of 2.72 inches in January 1960. During 1958 and 1959 daily evaporation exceeded 1 inch once each summer, and in 1960 three times during the summer. The daily evapora- tion in June and July for the 3 years averages about 0.70 inch. The ratio of annual pan evaporation to rainfall—90 to 1——is a measure of the aridity of Death Valley. At no other locality in the United States is the ratio known to be this great. Rainfall during late Pleistocene time was undoubt- edly many times greater and evaporation much less than that of the past 50 years. Remnants of bars and shorelines indicate that during this time the precipitation in the basin was suflicient to maintain 13—193 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 .28 53:9 £89 E x35 38 :o maofiuscwwmm 83.8w fish 35st a.“ 553m 3533 23 I3 «6383 ms 33 mag 8 $3 234 we v2.59 ufi Marla. 2055:0on oEwEmaIédn 5:55 .E< .55. do“. 62 own. .52 _ .80 .Ewm .m=< 23. 2:4 >m_>.‘ _ _ . _ . _ _ _ _ _ _ _ , EEoE L2 .28 — _ — .— — I 38% 285an $525 86 8.0 «no mg 8.0 $6 mg 2.0 2.0 8.0 8.0 C 25 I L 2:55 L2 .22 22% maneszv zo_hm . _ on? _ mm? 3m _ o; _ 8.: _ om: A 3.2 _ 3am _ KAN _ wm‘: >x/\/ L 2:55 L2 .32 28% waneszv FEES: ozzs I _ _ < \<1/ 33 con E 82 m3: moz.__._._D_S_DI m>_._.<4mm >::4 S 0 Little Creek at bridge near Swant n W X 0 Mill Creek, 0.25 miles southeast 3 O X of Seaside School W C) S O X Pescadero Creek at Pescadero X 0 Pescadero Creek, 4 miles east 5 X of Pescadero W 0 San Gregorio Creek, 2 miles 3 0 south of La Honda W x ' O Nameless Creek above Tunitas S 0 X Creek W X C Tunitas Creek above Nameless S O _ X Creek W OX ~ Tunitas Creek. 0.5 miles above S O X mouth W X D Purissima Creek, 2.5 miles aboi/e S X 0 mouth W X 0 S OX Purissima Creek near mouth W X O , >C Scott Creek at Seasude School W >__ G) g: 1 Columbia River basalt E 'U = l— flwl V . E 9.5 % ES “El Older rocks (inlying) mg '— 5 3 “l E 8 a B E 35 400’ 3001 200" 100’- CASCAD E l l [ORElGON r—l MILE —.’ Static piezometric surface of the water We Surface at 9'16 Enmpjfl8_ ‘ ” ‘ ' ——————— e _ _____ _ “4308) Wome O, " ”435% Stream (5 1/ 0 60 'M | LES l_g_1__.|_|_1__l -400’ ~300’ -200’ ~100’ DATUM DATUM FIGURE 88.1.—Top, Generalized map of the main area underlain by the Columbia River basalt; Bottom, Diagrammatic cross section of a hypothetical ground-water withdrawal system operating on an aquifer of a barrier reservoir. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 blocks and into less prom nent horizontal sheeting slabs. Except for the cooli g joints, most flows are rather monolithic; little b eccia or fragmental lava is present. Few sediment ry interbeds are present except around the edges of the basalt unit. Most in- dividual flows are dense nd tight in their center parts, but some are vesi ular, rubbly, and porous near their tops. Water p rcolates mainly along the porous tops of some of th lava flows. Tabular sep- aration of the aquifers is ommon, and the hydraulic conditions of such occur ences vary from place to place. The basalt has been tectonically warped into broad open folds with 10 al areas of intense defor- mation. Infiltrated wate moves down the dip of inclined porous flow top so that the downwarped areas are sites of groun -water accumulation. Locally structural def rmation has sheared and crushed the rock along f ults and along tight folds in which the porous top of the flows were crushed during the interflow slip age. These zones of crushed rock obstruct the tabular ercolation of ground-water 3—215 and cause impounding back to points of discharge. These ground-water reservoirs updip from struc- tural barriers occur in and near some of the valleys and in the uplands. Notable among the barrier reservoirs now in use is one underlying the Upper Cold Creek valley northwest of Pasco, Wash., and one under the Walla Walla valley plain at College Place west of Walla Walla, Wash. The hydraulic characteristics of a typical barrier reservoir in the basalt are illustrated in figure 88.1 (bottom). The impounded water is best tapped by wells at the barrier end of the reservoir. The peren- nial yield would be determined by the annual re- charge and would differ from reservoir to reser- voir. Withdrawals from reservoirs where flowing streams cross the intake area may decrease the streamflow; however, calculations on theoretical ex- amples suggest this deduction in stream flow, at its maximum in late summer, would equal only a small part of the water drawn from otherwise unused storage. ' 6% GEOLOGY AND HYDROLOGY OF ALASKA AND HAWAII 89. XENOLIT IC NODULES IN THE 1800-1801 KAUPULEHU FLOW OF HUALALAI VOLCANO By DONALD H. RI HTER and KIGUMA J. MURATA, Hawaiian Volcano Observatory, Hawaii, and Hualalai is one of t e five volcanoes whose flows have built up the island of Hawaii. Now dormant, it was last active in.180 —1801 when the Kaupulehu and smaller Huehue ows were erupted from its northwest rift zone. The presence of xenolithic nodules in the Kaupule u lavas has long been known, .but only limited men ion of them or of their re— markable occurrence s appeared in the literature. Stearns and Macdonal (1946) briefly described some 'of the physical featu es of the nodules and later Macdonald (1949) pre ented additional petrographi- cal data. Chemical an lyses of a clinopyroxene and a spine] from the Kaupu ehu nodules were given, along with a discussion on t e origin of dunitic inclusions, by Ross, Foster, and yers (1954). Recent geologic studies on Hualalai olcano have revealed some ex- ceptional exposures o nodules which indicate a pos- sibly greater abunda ce of nodules than heretofore Washington, D. C. believed, as well as a significant difference in their aggregate composition. The possible significance which these nodules may have in regard to the genesis of the Hawaiian lavas has prompted a detailed mineralogical-chemical study, now in progress; this paper describes the geologic occurrence and physical mineralogy of the nodules. The Kaupulehu flow, together with the Huehue flow, represents the youngest lavas of the alkalic basalt series which mantle Hualalai Volcano. On the basis of the well-established chronological succes- sion of Hawaiian magma types, however, the main bulk of Hualalai is believed to be composed princi- pally of basalts of the tholeiitic series. The tholeiitic rocks, characterized by a saturated groundmass, are erupted frequently and rapidly during the youthful and mature stages of volcanic activity; whereas the undersaturated alkalic basalts and their differen- . l l l l m... Rafi—_ ur , _ l l KAUPULEHU Wu ,‘ FIGURE 89.1.—Map of the island of Hawaii showing location of the 1800—1801 Kaupulehu flow on Hualalai Volcano. Outline of flow from report by Stearns and Macdonald (1949). ‘ tiates are erupted intermittently and in minor vol- ume during the decadent stage of volcanism. Xeno- lithic nodules appear to be restricted in their‘oc- currence to these later alkalic rocks, not only on Hualalai, but on other volcanoes of the Hawaiian Islands as well. The voluminous Kaupulehu lavas were erupted from a group of vents, between 5,500 and 6,000 feet in elevation, along the northwest rift of Hualalai, and with the exception of a few short tongues that flowed to the west, they flowed northward down the slopes of the volcano some 10 miles before entering the sea south of Kawaihae Bay (fig. 89.1). The nodule locality recently investigated is along a rela- tively flat bench, on the first major break in slope, 2 miles below the vent area at an elevation of about 3,250 feet. Briefly reconstructing the history of the flow, it appears that the rapidly flowing, extremely fluid lava—heavily charged with nodules—lost velocity and carrying capacity on reaching the area of re- duced gradient. Here the early flows spread out in relatively thin sheets, both on the level area and on the slopes below, depositing the nodules in well- defined layers. As lava continued to flow into the GEOLOGICAL SURVEY RESEARCH 1961 level area a pond of considerable depth soon formed, first by surface overflow and later by lava running under the surface and floating the crust. Eventually, as the lithostatic head increased, the impounded fluid lava broke through the downslope wall of the pond and cut'a deep channel through the nodule- bearing flows which had spread out earlier over the surface below the pond. As material drained out of the pond, the still fluid lava in many of the nodule zones also drained away leaving discrete nodule beds, without appreciable matrix lava. To- ward the end of eruptive activity, lava domes on the surface of the pond and portions of tubes within the pond collapsed, and it is in these collapse features together with the main lava channel below the pond that the spectacular nodule beds are now exposed. The great abundance of the nodules is well shown in the wall of the main lava channel where no less than 4 distinct nodule beds, ranging in thickness from 3 to 9 feet, are exposed (figs. 89.2 and 89.3). In fact, along one ZOO-foot long exposure, the nodule beds have an aggregate thickness of 26 feet and con- stitute more of the rock than the lava itself. In the collapsed domes and tubes on the top of the lava pond only the uppermost nodule bed is visible; and where collapse occurred prior to complete solidifica- tion of remnant matrix lava the nodules tumbled into the depressions forming an outcrop very similar in appearance to a cobble beach deposit (fig. 89.4). In size, the nodules generally range from a frac- tion of an inch to more than one foot in diameter; the largest observed measured 27 inches in its great- est dimension. They are angular to subrounded in FIGURE 89.2.—Wall of main lava channel inK'aupulehu flow showing four nodule beds (1, 2, 3, 4) each separated by several thin pahoehoe flows. SHORT PAPER IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 external form, although in the exposures where matrix lava has been w' hdrawn the thin coating of lava remaining on the . odules tends to accentuate their roundness. The nodules consist rincipally‘ of medium- to coarse-grained crystal a 1.; regates of one or more of the following three mi erals: clinopyroxene (ap- proximately CalgMgHFeH), olivine (Fauna), and plagioclase feldspar (An “-75). Opaque minerals are generally present in amunts ranging from a few tenths to 2 percent. T e crystals are all anhedral and form a tightly interlcked allotriomorphic granu- lar texture. With the e eption of a minute corona- like clinopyroxene gro th observed around some Opaques in a few spec'mens, the minerals do not exhibit any evidence 0 magmatic reaction. Some of the olivine grains, ho ever, do show an incipient marginal alteration pro 4: ably caused by the action of hot water-laden gases st earning through the nodules after the cessation of vlcanic activity. On the basis of mine alogy four general types of nodules are recognizabl. These types in order of de- creasing abundance, as .hown by random sampling of over 200 nodules, are: linopyroxene-olivine, olivine, clinopyroxene, and linopyroxene-feldspar. Only a few olivine-feldspa and olivine-clinopyroxene— feldspar nodules were observed, and predominantly feldspar nodules apprently do not exist. Modal analyses of representaive nodules from the different types indicate that cli opyroxene is the most abun- dant mineral present. ' FIGURE 89.3.—Closeup View of nodule bed 2, shown in figure 89.2. Spatter from the last flows through channel is draped over some of the nodules. 6Q . 1‘ FIGURE 89.4.—Loose nodules on the floor of a collapsed dome in the surface of the lava pond. Note the relatively thin lava caprock of the nodule bed. CONCLUSIONS Murata (1960) and Eaton and Murata (1960) support the theory that the fundamental Hawaiian magma is tholeiitic and that fractional crystalliza- tion of pyroxene is the principal mechanism for pro- ducing the undersaturated alkalic magmas. The mineralogy and abundance of the Kaupulehu nodules (together with the fact that xenolithic nodules, in general, occur only in alkalic rocks) lends additional support to this view. The nodules therefore, are in- terpreted to represent fragments of subterranean consolidated deposits of crystals whose precipitation has played a dominant role in affecting the funda— mental change in magma type. Furthermore their angularity and lack of pronounced magmatic reac- tion strongly suggest that the processes of frac- tional crystallization occurred far above the original source of the tholeiitic magma—probably in rela- tively shallow magma reservoirs within the volcano. REFERENCES Eaton, J. P., and Murata, K. J., 1960, How volcanoes grow: Science, v. 132, p. 925—938. Macdonald, G. A., 1949, Petrography of the Island of Hawaii: US. Geol. Survey Prof. Paper 214—D, p. 51—96. Murata, K. J., 1960, A new method of plotting chemical analyses of basaltic rocks: Am. Jour. Sci., V. 258—A, p. 247—252. Ross, C. S., Foster, M. D., and Myers, A. T., 1954, Origin of dunites and of olivine-rich inclusions in basaltic rocks: Am. Mineralogist, v.39, p. 693—737. Stearns, H. T., and Macdonald, G. A., 1946, Geology and ground-water resources of the Island of Hawaii: Hawaii Div. Hydrography Bull. 9, 363 p. B-218 GEOLOGICAL SURVEY RESEARCH 1961 90. RECONNAISSANCE OF THE KANDIK AND NATION RIVERS, EAST-CENTRAL ALASKA By EARL E. BRABB, Menlo Park, Calif. The purpose of this report is to describe briefly the rocks and structure along two previously un- mapped rivers in east central Alaska. All localities mentioned are shown on Charley River A—2, B—l, B—2, B—3, C—l, C~2 and D—l quadrangles, scale 1:63,360. All of the rocks cropping out along the Kandik River are provisionally assigned to the Kandik for- mation of Early Cretaceous age. They are predomi- nantly shale, mudstone, argillite, slate, and gray- wacke but include minor amounts of chert-pebble conglomerate, “clean” sandstone, pebbly mudstone, and cherty limestone. These rocks seem to represent one lithogenetic sequence. Graded beds and other features suggestive of turbidity current deposits are common. The rocks are intensely deformed between the mouth of the Kandik River and Easy Moose Creek and between Indian Grave Creek and the United States-Canada border. The beds have a gen- eral northeast strike and a moderate northwest dip between Easy Moose Creek and Indian Grave Creek, and an anomalous northwest strike and moderate northeast dip in the vicinity of the border. Pelecy- pods collected from the formation along the Kandik River about 2 miles upstream from the mouth of Big Sitdown Creek suggest an Early Cretaceous (Valan- ginian) age according to D. L. Jones (written com- munication, 1961). Slate, shale, mudstone, argillite, and minor gray- wacke and quartzite cropping out along the Nation River between the mouths of Tindir and Jungle Creeks are also provisionally referred to as the Kandik formation. These rocks are moderately to intensely deformed and appear to have an anomalous northwest strike. Several minor southeastward— plunging folds in these rocks can be seen near the mouth of Ettrain Creek. Most of the rocks are not well dated but all of the fossils collected from them indicate an Early Cretaceous age. For example, Foraminifera collected from shale along the Nation River near the mouth of Tindir Creek are possibly of early Neocomian age, according to H. R. Bergquist (written communication, 1961). Megafossils col- lected from the same beds and from another locality nearby were identified by D. L. Jones (written com- munication) as Polyptychites and Buchia cf. B. crassicollis and are also suggestive of an early Neo— comian (Valanginian) age. The Kandik formation may be in fault contact with petroliferous shale and limestone of Triassic age, Tahkandit limestone of Permian age, and Na- tion River formation of Carboniferous (Pennsyl- vanian ?) age, which crop out along the Nation River about 1 mile upstream from the mouth of Waterfall Creek. These late Paleozoic and early Mesozoic rocks have a northeast strike and, for the most part, a northwest dip. Conglomerate, sandstone, siltstone, and minor coal and “red beds” cropping out along the Nation River between Waterfall and Hard Luck Creeks are also provisionally referred to the Nation River formation. These rocks have a northeast strike and southeast dip. They are apparently in fault contact with shale and limestone about 2 miles downstream from the mouth of Hard Luck Creek. Corals from the limestone are of Silurian or De- vonian age, according to W. A. Oliver, Jr. (written communication, 1961). No oil seeps or deposits of economic interest were found. ’X‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—219 GEOLOGY 0F PUERTO RICO 91. HYDROTHERMALLY ALTERED ROCKS IN EASTERN PUERTO RICO By FRED A. HILDEBRAND, Denver, Colo. Work done in cooperation with the Department of Industrial Research, Puerto Rico Economic Development Administration A belt of light-colored altered rocks approximately 50 km long and 5 km wide extends from the eastern coast of Puerto Rico northwest to the Cerro La Tiza area, as shown in figure 91.1. The altered belt skirts, the northern edges of the San Lorenzo and Caguas plutons and lies within a broad zone of'structural weakness trending about N. 70° W. across north- central Puerto Rico (Smith and Hildebrand, 1953; Hildebrand and Smith, 1959). Within the belt, ex- posures of hard altered quartzose rock stand in relief as ridges and knolls above the softer vol- canic country rocks. The greenish-gray volcanic country rocks consist principally of lava, tufi', tuff and volcanic breccia, and agglomerate. In general, the volcanic rocks are of borderline basaltic-andesitic composition and their age is probably Cretaceous and early Tertiary (Hildebrand, 1959). The plutonic rocks shown on figure 91.1 consist mainly of granodiorite. Zircon age determinations indicate that the San Lorenzo pluton is of late Cre- taceous or early Tertiary age. The age of the Caguas pluton has not been determined. On the whole the altered rocks are light colored and consist of intermixed hard, massive quartzose rocks and soft, clayey, sericitic rocks composed prin- cipally of quartz, sericite, alunite, pyrophyllite, kao- linite, and halloysite. Less abundant minerals are hematite, goethite, diaspore, zunyite, jarosite, barite, sulfur, pyrite, and svanbergite. The belt of altered rocks is not continuous but consists of elongated patches of altered rock (fig. 91.1) surrounded by unaltered country rock. Within the patches of altered rock there is no distinct zoning of rock types, however, elongated zones.of hard banded quartz-alunite rocks and soft foliated, pyrophyllitic rocks commonly occur within softer, clayey sericitic rocks. At the western end of the belt, where the terrain is generally higher, the altered rocks have weathered to an earth-rock debris that has moved downslope to form extensive tongue and apron deposits over the volcanic country rocks. The mineral assemblages at the largest and best exposed areas along the hydrothermal belt are listed in table 1. Most noteworthy observations at these areas are as follows: 1. At Cerro La Tiza and Pueblito Del Rio, alunite and quartz occur as alternating bands in finely banded and crenulated rock. The banding is believed to be inherited from the foliated struc- ture of the volcanic host rock. 2. At Cerro La Tiza and Cerro Marquesa, kaolinite, and halloysite are more abundant at the south- ern margins of the altered zone. The margins of the zones in other areas are concealed. 3. Crystalline pyrophyllite and diaspore are most abundant at Cerro Marquesa. 4. Between Aguas Buenas and Gurabo the rocks are mainly silicified and sericitized volcanic host rocks. Further study of quartz-sericite rocks in this area may show that they are greisen. 5. That part of the belt richest in barite borders the north edge of the San Lorenzo pluton from Cantagallo eastward to Pueblito Del Rio. 6. Kaolinite and halloysite are generally less abun- dant and zunyite and jarosite more abundant toward the eastern end of the belt. The altered rock belt shown in figure 91.1 is be- lieved to be of hydrothermal origin; that is, the vol- canic host rocks were altered by emanations from a magmatic source. The emanations probably origi- nated in plutonic rocks that presumably underlie much of Puerto Rico (Hildebrand, 1959). The a1- teration processes have destroyed all primary tex- tures of the volcanic host rocks and have caused profound compositional changes that have resulted in a completely different mineral assemblage. Cal- cium, magnesium, and most of the iron were re- moved from the host rocks, but silica, sulfur, and probably potassium were added during the altera- tion processes. The abundance of introduced quartz, aluminum silicates and sulfate-bearing minerals is evidence that the emanations were acid, sulfate bear- GEOLOGICAL SURVEY RESEARCH 1961 B—220 52m 3.89m 533w 5 $32 3:529» 95 02353 8. aEwnofiflwy .323 was mxuoa @333 5:55:52th 90 £3 AOHBSOIAAm 85.3% ‘ _ Colonia J unio as x ras EXPLANATION OHUMACAO @ Belt of hydrothermally altered rocks . S A N LO R E N 20 a Magnetite ore bodies \ /- ‘‘‘‘‘ ‘\ Inferred margin of platonic rocks 5 P L U To N be?) Dashed where approximate [I “$9, €32 // Yabucoa 6&0 1/ q\ l \\ PUERTO RICO \ ‘6‘ . — Faun” o 5 1o KILOMETERS'_18°°°' l_l_.___1—J o 5 MILES 1 CARIBBEAN SEA 1 FIGURE 92.1.-—Index map showing position of greisen area in the long belt of hydrothermally altered rocks and relation of greisen area to plutonic rocks and magnetite ore bodies. Area shown in details in figure 92.2 is outlined. \\ Cagu fills \\ V/ ///*r ‘ 66 ° 00’ EXPLANATION 1 2°. o Outcrops of volcanic country rocks Outcrops onic rocks N Outcrops of greisen Inferred contact betweeuriAplutonic and vol- canic rocks or pluwnic rocks and greisen \ g" ‘ § \\ \\ a 1 KILOMEl’ER’S // ” 1 000 2000 // 3000 F E ET/// / 0W 1/, ll CENTRAL SANTA JUANAW FIGURE 92.2.—0utcrop map showing relation of greisen to plutonic and country rocks. B—224 freshest specimens as a thin yellowish-brown crust in tiny vugs and as minute colloform clusters. The greisen probably developed from hydrother- mal alteration of the volcanic country rocks by ema- nations from the Caguas pluton or from similar plu- tonic rocks at depth. The mode of origin is in agreement with stability relations among these min- erals as outlined by Hemley (1959). The temperature necessary for the deVelopment of andalusite was probably above 400°C, which is too high for the development or existence of kaolinitic clays that occur elsewhere in the long, broad hydrothermally altered belt (Hildebrand, 1959)‘. By comparison with the minerals of the volcanic host rock the abundance of muscovite, topaz, and iron minerals in the greisen indicates that potassium, silica, iron, 1 This belt is described in article 91 of this volume. Although information on the temperature of formation of some minerals of this assemblage is lacking at this time, presumably the greisen zone was formed at a some- what greater temperature than was the rest of the hydrothermally altered belt. GEOLOGICAL SURVEY RESEARCH 1961 and fluorine were introduced into the host rocks. Because of the lack of minerals containing sodium, calcium, and magnesium, these cations must have been removed from the minerals of the host rock. The hematite in the greisen may be of hydrothermal origin but it may also have developed by alteration from magnetite. Assuming that the greisen pre- viously contained primary magnetite that is now hematite and goethite, it seems likely that this greisen zone may be related in origin to magnetite ore bodies that occur between the hydrothermal belt and the plutonic rocks (fig. 92.1). REFERENCES Hemley, J. J., 1959, Some mineralogical equilibria in the sys- tem Kgo-ALOa—Si02—H201 Am. Jour. Sci., V., 257, p. 241— 270. Hildebrand, F. A., 1959, Zones of hydrothermally altered rocks in eastern Puerto Rico [in Spanish]: Commonwealth of Puerto Rico, Dept. Indus. Inv., Econ. Devel. Adm., Tech. Inf., p. 82—96. 6% 93. ASH-FLOW DEPOSITS, CIALES QUADRANGLE, PUERTO RICO, AND THEIR SIGNIFICANCE By HENRY L. BERRYHILL, JR., Denver, Colo. Work done in cooperation with the Department of Industrial Research, Puerto Rico Economic Development Administration The only known ash—flow deposits ' in Puerto Rico are in the north-central part of the island within and adjacent to an arcuate northwest-trending graben about 30 km long and 3 km wide (Berryhill and others, 1960). A segment of this graben crosses the southern part of the Ciales quadrangle (fig. 93.1), which was mapped in 1958—59 with the assistance of Fred A. Hildebrand. The ash-flow deposits rep- resent a specific phase of a regional volcanic cycle. Special thanks are extended to Ray E. Wilcox, whose knowledge of volcanic processes was freely given and extensively utilized during the study of these rocks. 1 The term “ash flow” is applied here according to the nomenclature of Smith (1960, p. 800). STRATIGRAPHY The lower member of the Coamo formation in the Ciales quadrangle (Berryhill and others, 1960) is about 495 m thick and consists of ash-flow de- posits interbedded with conglomerate, lapilli tufi', and reworked coarse and fine tufi'. A reddish color distinguishes this sequence of rocks from all other volcanic rocks in north-central Puerto Rico. Lenticular and very dense ash-flow deposits within the sequence range in thickness from 10 to 40 m and extend laterally for at least 4 km in dis- continuous outcrops. The ash-flow deposits consist primarily of plagioclase crystals, devitrified glass shards, fragments of feldspathic oxidized lava, pum- 3 ice, and a very fine ash matrix containing iron oxide SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 OROCOVIS 30 KlLOM ETERS O 10 2O B—225 EXPLANATION Quaternary deposits and middle Tertiary limestone Lower Tertiary granodiorite and dioritic intrusive rocks Upper Cretaceous dacitic ash flows and associated rocks E Cretaceous volcanic rocks; includes some lower Tertiary rocks A ‘‘‘‘‘ ’/ Contact Dashed where approximately located U A a.) “ Fault U, upthrown side; D, downthrown side. Ar- rows indicate direction of strike-slip movement __~ \ i . \\ Syncline, approximately located ‘1‘ Strike and dip of beds FIGURE 93.1.—Map of eastern Puerto Rico showing location of ash-lilow deposits. dust. The plagioclase crystals are highly fragmented, the microscopic glass shards are altered, mostly to quartz and clay, and the flattened pumice bombs and much of the matrix have been altered to a clay mineral (nontronite?), quartz, and zeolites. A con- centration of plagioclase crystals is common at the base of the deposits. Welding of the glass shards and fragments under intense heat and pressure at time of emplacement is a distinctive feature of the lower part of each in- dividual ash-flow deposit. The degree of compaction and cohesion decreases from base to top. Basal parts of most deposits have vitroclastic texture, but they also have a distinct parallelism of shards and flat- tening of pumiceous bombs. Upper parts of flows are nonwelded tuif comprised primarily of pumi- ceous and feldspathic lava fragments and iron-rich chert. The sequence of rock types and the crude zonation within an ash-flow deposit are described in the fol- lowing representative section: Section of an ash-flow deposit 200 m west of Quebrada Blacho in clifl‘ adjacent to Rio Toro Negro, northern part of barrio Pozas, Ciales quadrangle Thickness Tap (meters) 6. Lapilli tufl‘, nonwelded except for very slight weld- ing at base, reddish brown, compact; intermixed fragments of pumice, oxidized feldspathic lava, and iron-rich, reddish-black chert. Fine matrix Thickness (meters) makes up less than 20 percent of total mass, frag- mented plagioclase crystals less than 15 percent. Some fragments have heat reaction rims; pumice bombs are compressed only in basal part ________________ 26 5. Lapilli tufl‘, partially welded, reddish brown; hetero- geneous mixture of partially sericitized frag- mented plagioclase crystals, oxidized feldspathic lava fragments, devitrified glass shards, and com- pressed pumice bombs well alined parallel to stratification. Reddish, fine-grained matrix, largely altered to zeolite(?), quartz, and non- tronite(?), makes up 40 percent of total mass; plagioclase crystals about 15 percent ______________________ 3 4. Tufl", welded, reddish-brown, with sparse fragments of feldspathic lava as much as 5 mm long, vitro- elastic; abundant iron oxide dust; fragmented plagioclase crystals make up about 15 percent of mass; all pumice bombs compressed; feldspathic lava fragments have heat-reaction rims ________________ 5 3. Tufi’, welded, reddish-gray, vitroclastic; all pumice bombs compressed and altered to nontronite(?); fragmented plagioclase crystals comprise about 15 percent of mass _ 0.5 2. Tufl", welded, reddish-brown, vitroclastic-fluidal tex- ture; consists of pulverized andesine(?) crystals in a flour of quartz, iron oxide, zeolite(?), and nontronite( ?) ; plagioclase makes up about 40 per- cent of mass." .3 1. Crystal tufl", welded, vitroclastic-fluidal texture; highly fragmented, cracked, and bent andesine(?) crystals make up about 50 percent of mass (repre- sents sole of ash flow) __________________________________________________ .07 Base of ash-flow deposit. Top B—226 TABLE 1.—Chemical and approximate mineral composition of a dacite ash-flow deposit and of granodiorite from the Ciales stock, north—central Puerto Rico [Analysts2 P. D. Elmore, I. H. Barlow, S. D. Botts, and Gillison Chloe! Norms Granodiorite Dacite _____________________ Granodiorite Dacite Si02 61.3 63.7 Q 14.9 Q 16.8 A1203 16.4 16.5 or 20.0 01' 25.0 Fe203 3.0 3 . 7 ab 28.8 ab 36.6 Fe() 2.7 1.0 an 19.5 an 10.0 MgU 2. 1 I .3 c .l .3 .\In0 .18 .15 we 2.4 Ca() 5.] 2.2 en 5.2 on 3.2 N320 3.4 4.2 is 2.8 K20 3.4 4.2 mt 4.4 mt 1.6 H20 1.1 2.2 il 1.1 il 1.1 Ti02 .56 .74 ap l .0 ap 1.3 P205 .40 .22 he 1.3 CO2 .07 .06 r .2 Total 99.61 100.17 100.1 98.4 The age of the ash-flow deposits, based on cor- relation with fossil-bearing marine rocks of the Coamo formation elsewhere in Puerto Rico, is latest Cretaceous (Maestrichtian). Massive gray poorly stratified andesitic volcanic breccia and possibly re- worked marine tuffs of Late Cretaceous(?) and early Tertiary age overlie the ash-flow deposits. Chemical analyses and normative mineralogic cal- culations (table 1) indicate that the ash—flow de- posits are dacite. STRUCTURE The graben that contains the ash-flow deposits is bounded on the southwest by a regional strike-slip fault and on the northeast by a fault that is sub- sidiary to the regional fault (fig. 93.1). The throw of the graben increases progressively toward the southeast end where the ash-flow deposits are in juxtaposition with basaltic pillow lavas that are sev- eral thousand meters stratigraphically lower than the ash-flow deposits. The rocks within the graben form a syncline, although internal faulting has seg- mented the graben into tilted blocks. GEOLOGICAL SURVEY RESEARCH 1961 REGIONAL RELATIONS AND SIGNIFICANCE Ash-flow deposits of dacitic composition on top of a pile of andesitic tuffs and basaltic pillow lavas several thousand meters thick, suggest a progressive change in the composition of magmas that supplied the Late Cretaceous volcanic materials. Although both overlain and underlain by volcanic breccia and tufi' that are obviously marine, the Coamo formation ash-flow deposits are probably sub- aerial in origin as shown by interlayers of fluvial gravel and nonstratified mudfiow deposits, and plant- root casts. Moreover, as pointed out by Rankin (1960, p. 32), an ash flow (the specific gravity of which is well below unity) could not be propagated under water, much less become welded. The geographic and structural position of the graben relative to plutonic intrusives (fig. 93.1) and the restricted occurrence of ash-flow deposits within and adjacent to the graben suggest that the area of accumulation was initially outlined by sagging of a crustal segment above a magma chamber. Faulting, both contemporaneous with and subsequent to ash- flow deposition, formed the graben. The chemical and mineralogical similarity (table 1) of the dacite ash-flow deposits and the granodiorite in the nearby stocks suggests that the ash-flow deposits represent expulsion of volatile-rich magmatic material from these plutonic bodies after they had moved upward into the near-surface crustal zone. REFERENCES Berryhill, H. L., Jr., Briggs, R. P., and Glover, Lynn, III, 1960, Stratigraphy, sedimentation, and structure of Late Cretaceous rocks in eastern Puerto Rico—preliminary report: Am. Assoc. Petroleum Geologists Bull., v. 44, no. 2, p. 137—155. Rankin, D. W., 1960, Paleogeographic implications of deposits of hot ash flows: Internat. Geol. Cong., let, Copenhagen, 1960, sec. 12, pt. 12, p. 19—34. Smith, R. L., 1960, Ash flows: Geol. Soc. America Bull., v. 71, no. 6, p. 795—846. 6% SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—227 PALEONTOLOGY AND PLANT ECOLOGY 94. REPLACED PALEOCENE FORAMINIFERA IN THE JACKSON PURCHASE AREA, KENTUCKY By I. G. SOHN, S. M. HERRICK, and T. W. LAMBERT, Washington, D. C., Atlanta, Ga., and Paducah, Ky. Abundant replaced Foraminifera were recognized by Sohn in a glauconitic sandy claystone of the Clay- ton( ?) formation near Reidland, 8.2 miles southeast of the Paducah Court House. The fossiliferous bed is in a bank of a tributary of the Clark River, in which the following formations are exposed: Section near Reidland, McCracken County, Ky. (Paducah East 7%-minute quadrangle measured by T. W. Lambert) Paleocene. Feet Porters Creek clay: Black claystone _____________________________________________________________ 10 Clayton(?) formation: Glauconitic claystone, sandy; Foraminifera and barite(?) crystals Upper Cretaceous. Owl Creek(?) formation: Black claystone Black glauconitic claystone __________________________________________ McNairy sand: Interlaminated lignitic clay and fine-grained micaceous sandstone __________________________________________________ 2to3 _____________ 6 5(?) 15+ The bulk of the faunule is small enough to pass through a 100-mesh screen, although some large specimens also are present. The following forms were identified by S. M. Herrick: Reophax? sp. Textularia midwayana Lalicker, 1935 Clavulinoides midwayensis Cushman, 1936 Adhaerentia midwayensis Plummer, 1938 Robulus midwayensis (Plummer), 1927 cf. R. rosettus (Giimbel). Cushman, 1940 Dentalina cf. D. cooperensis? Cushman. Cooper, 1944 Nodosaria latejugata Giimbel, 1870 Chrysalogonium eocem’cum? Cushman and Todd, 1946 Ramulina cf. R. aculeata (d’Orbigny). Cushman, 1940 Nonionella sp. Bolivinopsis cf. B. rosula (Ehrenberg). Cushman, 1949 Guembelina morsei Kline, 1943 Siphogenerinoides eleganta (Plummer). Cushman, 1940 Bulimina cacumenata Cushman and Parker, 1936 (Desinobulimina) quadrata Plummet. Cushman, 1940 Bolivina midwayensis Cushman, 1936 midwayensis Cushman, 1936 Loxostomum deadem'cki Cushman, 1947 deadericki Cushman var. exilis Cushman, 1947 Ellipsonodosaria paleocenica? Cushman and Todd, 1946 Valvulinem'a wilcoxensis Cushman and Ponton, 1932 Gyroidina aequilateralis (Plummer). Cushman, 1944 Gyroidina subangulata (Plummer). Cushman, 1940 Siphom'na prima Plummer, 1927 wilcoxensis? Cushman, 1927 Asteriger’ina primaria Plummer, 1927 Alabamina wilcoxensis Toulmin, 1941 Pullem‘a quinqueloba (Reuss). Cushman, 1940 Globige’rina pseudo-bulliodes Plummer, 1927 triloculinoides Plummer, 1927 Anomalina midwayensis (Plummer). Cushman, 1940 acuta Plummer, 1927 clementiana (d’Orbigny). Franke, 1925 Cibicides allem’ (Plummer). Plummer, 1933 newmomae (Plummer). Cushman and Todd, 1942 When tested with dilute hydrochloric acid, speci- mens belonging in normally calcareous foraminiferal genera did not dissolve. Charles Milton determined that the foraminiferal tests are composed of a mix- ture consisting of hulandite and, probably barite. Crystals probably composed of barite are found with the fossils. Switzer and Boucot (1955) record foraminiferal tests replaced by heulandite in specimens of Paleo- cene age from a well near Jackson, Tenn., at depths 483—509 feet. Barite has not yet been recorded as replacing foraminiferal tests, although megafossils replaced by barite are known (Ladd, 1957, p. 23). The only other record of Tertiary Foraminifera in the Upper Mississippi Embayment is that by Cooper (1944). He described a foraminiferal assemblage of Paleocene age from the Porters Creek formation in well samples from depths of 115—135 feet at Cache, Alexander County, Ill. These fossils are calcareous. Lamar and Sutton (1930) pointed out that absence of calcareous material is one of the outstanding features of most of the Cretaceous and Tertiary sedimentary rocks in Kentucky, Illinois, and Mis- souri. They suggested that the absence of fossils is due to leaching. Replaced fossils near the surface at Reidland, and unreplaced fossils at a depth of more than 100 feet in Illinois support that hy- pothesis. REFERENCES Cooper, C. L., 1944, Smaller Foraminifera from the Porters Creek formation (Paleocene) of Illinois: Jour. Paleon- tology, v. 18, p. 343—354, pls. 54, 55. Ladd, H. S., 1957, Treatise on marine ecology and paleoecol- ogy: Geol. Soc. America Mem. 67, v. 2, 1077 p. B—228 Lamar, J. E., and Sutton, A. H., 1930, Cretaceous and Tertiary sediments of Kentucky, Illinois and Missouri: Am. Assoc. Petroleum Geologists Bull., v. 14, p. 845—866, 3 figs. 95. ’5? GEOLOGICAL SURVEY RESEARCH 1961 Switzer, George, and Boucot, A. J., 1955, The mineral com- position of some microfossils: Jour. Paleontology, v. 29, p. 525—533. COAL-BALL OCCURRENCES IN EASTERN KENTUCKY By JAMES M. SCHOPF, Columbus, Ohio Coal balls containing abundant petrified plant re- mains were found beneath the marine Magoflin beds of Morse (1931) in eastern Kentucky during field seasons of 1949, 1950, and 1951. Apparently, these are the oldest coal-ball occurrences known in North America, and the first to be found in the Appa- lachian province. The eastern Kentucky coal balls are intermediate in age between those known from the Lower Coal Measures of Britain and the Interior basins in the United States. Collections of this ma- terial have been studied intermittently by me since autumn 1950. I am indebted to John W. Huddle, John E. Johnston, and other U. S. Geological Sur- vey geologists for knowledge of the Kentucky oc- currences, which are listed below: 1. Shock Branch. Creek-bed outcrop half a mile above the confluence of Shock (Shack) Branch with Rockhouse Creek, about 3 miles south- west of Hyden, Leslie County, Ky. 2. Lewis Creek. Creek—bed outcrop one-fourth mile above confluence of Lewis Creek with Left Fork, about 4 miles east of Chappell townsite, Leslie County, Ky. 3. Bear Branch. Outcrop in ravine on southeast slope about three-fourths mile from the point where Bear (Briar) Branch empties into North Fork of Kentucky River, about one mile west of Cornettsville townsite (Dent), Perry County, Ky. The Magoflin beds of Morse (1931, p. 302—303) represent one of the most widely distributed and easily identified stratigraphic “markers” of eastern coal measures. In some places, the marine beds are distinguished chiefly by impressions of invertebrate fossils in shale; in other places, they are accompa- nied by limestone masses of lenticular concretionary habit. A lower limestone layer a few inches thick is most persistent and, near the Lewis Creek 0c- currence, this bed thickens and resembles a coquinoid breccia. The Magoflin beds of Morse (1931) are discussed by Johnston and others (1955) in the Cornettsville area and have been widely identified by Wanless (1939, p. 53; 1946, p. 145). McFarlan (1943) also has discussed the occurrence of this marine zone in Kentucky. Wanless (1957, p. 73) indicated that the Magofiin beds of Morse (1931) were correlated with the Winefrede limestone of West Virginia, the Lower Mercer limestone of Ohio and Pennsylvania, the Minshall limestone of Indiana, the Verne limestone of Michigan, and the Curlew and Seville limestones of Illinois. The eastern Kentucky coal balls occur close below the marine beds at Shock Branch and Lewis Creek and apparently occupy the position of the Copeland coal of Morse (1931). They evidently arewithin Read’s (1947) Nem'opteris tenm’folia zone of late Kanawha (Mercer) age. The relation of the Bear Branch coal balls to the principal marine zone is less definite (J. E. Johnston, written communica- tion) ; they probably are slightly older than those at the other localities. _ The coal balls consist of limestone having less than 10 percent included plant substance. They generally appear light buff to brown on weathered surfaces, and include whiter areas of purer calcite and darker areas due to crusts of coal. Coal balls range from the size of small pisolites to large solid aggregated masses as much as a yard thick. Coal balls charac- teristically are restricted to local areas in a coal bed, and, in this respect, the eastern Kentucky coal balls are typical. The coal bed beneath the limestone is not thick, and it becomes particularly inconspicuous . in the presence of abundant coal-ball deposits. Plant assemblages from coal balls at all three localities appear similar and include calamites and SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 “130] B-229 l0 mm FIGURE 95.1.—1, Cross section of Bear Branch coal ball showing arrangement of peaty plant material. Stigmarian axis (a), stigmarian roots radiating from axis (b), calamite stem fragments (c), and fine vegetable debris in- cluding tiny leaves, stems, spores, and seeds ((1). 2, Cross section of delicate stigmarian root from Bear Branch coal ball showing original form. Central air cavity (a), conductive strand (b), and parenchymatous outer cortex (c). lepidophytes in abundance; Botryoptem's, Cardiocar- pan, M edullosa, and other elements may be new. Coal balls represent petrified peat litter, or peat, of Carboniferous age. A cross section of one of the coal balls shown in figure 95.1.(1) illustrates the arrangement of peaty plant material. If it had not been petrified, this peat would have contributed a layer of coal to the thin coal bed. The brown colora- tion of coal-ball limestone is mostly derived from the natural color of the original peat preserved in a finely crystalline to cryptocrystalline calcite matrix. Spherulitic or concretionary bands of crystal pat— terns in the matrix often pass through plant fossils without notable interruption. However, tissue pres- ervation is mostly a result of mineral infiltration and impregnation, rather than replacement. The cell walls of tissues generally are intact and mineral infiltration has been early and rapid enough to pre- serve even residues of protoplasmic substances in- side the cells of some fossils. Preservation of deli- cate cytologic structures of fossil plants is not as unusual as was once supposed, but it serves to empha- ize the quality of preservation in some of these coal balls. A common type of delicate tissue preservation is illustrated in figure 95.1(2) by a section of stig- marian root showing its original form. Preservation generally is poor Wherever plant substance is ac- tually replaced by mineral matter. A few vugs and veins represent a later generation of coarsely crystal- line calcite within larger coal balls. Petrified tissues are interrupted in these areas. The marine limestone associated with these coal balls is argillaceous, calcite—cemented, and contains small cavities. Weathered surfaces are mottled buff or gray. Many dissociated crinoid stem segments, worn brachiopod valves, small gastropods, bryozoan fragments, and one shark tooth have been observed. Pebbles and small cobbles of the brown coal-ball limestone also may occur within this coquinoid matrix, but these appear to be erratic, redeposited in the coquina. The surfaces of these coal-ball pebbles are rounded, with some re-entrant cavities. Some rounding may come from local transport, but the cavities suggest etching or solution. The coal balls themselves, the later generation of coarsely crystalline veins, and the coquina cement all show that excess calcium carbonate was present during petrification and early diagenesis. Preservation of cytologic details in some of the land plant remains strongly indicates early and rapid initial precipitation of coal-ball calcite. The close association with an overlying marine limestone in eastern Kentucky is similar to relations at other coal- ball localities such as those at Berryville, Ill. and West Mineral, Kans. described by Mamay and Y0- chelson (1953). Henbest (1958) has discussed ecologic implications of a similar deposit in the Secor coal bed near McAlester, Okla. The marine invasion over the coal swamp evidently was so rapid that it corresponds to a “local catyclism.” The same interpretation seems applicable to occurrences in B—230 eastern Kentucky and nearly all the other 20-odd occurrences I have examined in the Interior coal fields over the past 30 years. REFERENCES Henbest, L. G., 1958, Ecology and life association of fossil algae and Foraminifera in a Pennsylvanian limestone, McAlester, Oklahoma: Cushman Foundation for Fora- miniferal Research, v. 9, pt. 4, p. 104—111. Johnston, J. E., Stafl'ord, P. T., and Welch, S. W., 1955, Pre- liminary coal map of the Cornettsville quadrangle, Perry, Knott, Letcher, Harlan, and Leslie Counties, Kentucky: U.S. Geol. Survey Coal Inv. Map C—22. McFarlan, A. C., 1943, Geology of Kentucky: Lexington, Univ. Kentucky, p. 105—106. GEOLOGICAL SURVEY RESEARCH 1961 Mamay, S. H., and Yochelson, E. L., 1953, Floral-fauna] associations in American coal balls: Science, v. 118, p. 240—241. Morse, W. C., 1931, The Pennsylvanian invertebrate fauna of Kentucky: Kentucky Geol. Survey, Ser. VI, v. 36, p. 296—349. Read, C. B., 1947, Pennsylvanian floral zones and floral provinces: Jour. Geology, v. 55, p. 271—279. ’Wanless, H. R., 1939, Pennsylvanian correlations in the east- ern Interior and Appalachian coal fields: Geol. Soc. America Spec. Paper no. 17, p. 1—130, 9 pls. 1946, Pennsylvanian geology of a part of the Southern Appalachian coal field: Geol. Soc. America Mem. 13, p. 1—161, 40 pls. 1957, Geology and mineral resources of the Beards- town, Glasford, Havana, and Vermont quadrangles: Illinois Geol. Survey Bull. 82, 233 p., 7 pls. 6b 96. AGE OF THE OHIO CREEK CONGLOMERATE, GUNNISON COUNTY, COLORADO By D. L. GASKILL, Denver, Colo. The discovery of fossil plants in the Ohio Creek conglomerate about 10 miles northwest of the type locality in the Anthracite quadrangle, Gunnison County, 0010., indicates a Paleocene age for the formation. The Ohio Creek beds were first referred to by Hill (1890), and by Cross (1892), and mapped as the Ohio formation by Eldridge (1894). In the northwest quarter of the Anthracite quadrangle the Ohio Creek conglomerate is a light-gray to white, conglomeratic, feldspathic, quartzose sandstone un- conformably overlying beds assigned to the Mesa— verde formation (Lee, 1912), and unconformably overlain by the Wasatch (“Ruby”) formation. The Ohio Creek beds are generally massive, conglomeratic at the base, with a few conglomeratic lenses or peb- ble layers above. Grain size is predominantly medium to coarse, but individual lenses range from very fine to very coarse angular-grained sandstone. Grains of quartz predominate. Weathered feldspar locally constitutes 15 to 30 percent of the matrix. Scattered grains of chert, argillite, and occasional rounded granules of chert are common constituents. Some lenses contain flakes of biotite, muscovite, and less commonly, grains of pink feldspar and hornblende. At places, particularly at the base of the forma- tion, there is much argillaceous and carbonaceous material, including thin lenses and pellets of green- ish-gray clay, thin silty shaly layers, and carbonized wood fragments. The conglomeratic lenses are com- posed of smooth generally well-rounded, poorly ce- mented pebbles and cobbles of variously-shaded gray, red, orange, yellow, or brown chert and quartzite, white quartzite, quartz, argillite, and claystone, and an occasional pebble of igneous or volcanic rock. The pebbles and cobbles range from about 14 to 3 inches in diameter, but most of them are 1%; to 11/2 inches in diameter. At one locality numerous boulder—size concretions and concretionary lenses of hard dense fine-grained sandstone were found. Torrential cross- bedding commonly occurs within the individual lay- ers. The mineral composition seems to be rather uniform, although no microscopic examinations were made. The thickness of the formation ranges from about 15 to 80 feet in this area. Fossil plants were collected from a locality on the ridge north of Middle Anthracite Creek at an elevation of 9,100 feet in the NI/l sec. 1, T. 13 S., R. 88 W., 6th P.M. From this collection, J. A. Wolfe (written communication, 1960) identified “Juglans” rhamnoides Lesquereux, “Magnolia.” magnifolia. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 Knowlton, and Platomus regularis Knowlton. Wolfe states: The “Juglans” rhamnoides is known from several Paleocene floras, but has also been recorded (erroneously I think) from Late Cretaceous floras. The other two species are only known from Paleocene floras such as the Raton and Denver. This small flora is certainly of Paleocene age, and is probably correlative with the early Paleocene Raton and Denver floras * * *. The species identified are characteristic forms of the Paleocene and preclude a Cretaceous age. B—231 REFERENCES Cross, Whitman, 1892, Post-Laramie deposits of Colorado: Am. Jour. Sci., 3rd ser., v. 44, no. 259, p. 19—42. Eldridge, G. H., 1894, Description of the sedimentary forma- tions, in Anthracite-Crested Butte quadrangles, Colorado: U.S. Geol. Survey Geol. Atlas, Folio 9, p. 6~10. Hill, R. C., 1890, Orographic and structural features of Rocky Mountain geology: Colorado Sci. Soc. Proc., v. 3, p. 362— 458. Lee, W. T., 1912, Coal fields of Grand Mesa and the West Elk Mountains, Colorado: U.S. Geol. Survey Bull. 510, 237 p. 5% 97. BIOHERMS IN THE UPPER PART OF THE POGONIP IN SOUTHERN NEVADA By REUBEN J. Ross, JR., and HENRY R. CORNWALL, Denver, Colo., and Menlo Park, Calif. Recent stratigraphic study in southern Nevada has led to the recognition of large bioherms of very pure limestone in the upper part of the Pogonip group (Early and Middle Ordovician). These are known at Meiklejohn Peak in the Bare Mountain quadrangle (Cornwall and Kleinhampl, 1960), south- west of Aysees Peak in the Frenchman Lake quad- rangle, and probably west of Oak Spring in the northern part of the Tippipah Spring quadrangle. In cross section these bioherms are great lens- shaped masses almost flat on the bottom and convex upward on the top. The largest, located on the west side of Meiklejohn Peak (fig. 97.1), is estimated to be 250 to 300 feet in maximum thickness and ap- proximately 1/3 mile in lateral extent. All these masses are composed of light-gray aphanitic lime- stone of a massive nature that shows very few in— ternal depositional structures. However, detailed petrologic work is yet to be done. All the bioherms are in the lower part of the Antelope Valley limestone of southern Nevada. Specifically they rest almost directly on top of unit F of Johnson and Hibbard (1957, p. 347) and they extend upward within what those authors call unit G. It is of considerable importance to note that unit G does not increase in thickness where the bioherms are present. Its top and bottom limits remain essen- tially parallel. The bed on which each bioherm rests is seemingly continuous underneath the bioherm. Surrounding beds above the base are composed mostly of impure silty and muddy limestones which are highly fossili- ferous and are characterized in particular by the presence of trilobites that suggest correlation with the Kanosh shale of Hintze (1952, p. 20—23) and of the brachiopods of the Orthidiella zone of Nolan, Merriam, and Williams (1956, p. 28—29). Each of these surrounding beds seems to grade laterally into some portion of the upper convex side of the bioherm in which it loses its identity within a few feet. Al- though there is locally an appearance of “wrapping around” the upper surface of the bioherm, no single bed can be found to overlie its curved surface for an appreciable distance. At no place have we been able to find a truly distinct contact along the sloping sides of the bioherm. We infer that the surrounding muddy beds were deposited while the bioherm was growing and that its mass was not developed and then buried at a later date. Our examination of lithologic features has been only cursory and was undertaken only at Meiklejohn Peak. There, small masses of thinly laminated lime- stones, in which the laminae appear complexly con- torted, are present within the base of the bioherm. The boundaries of the laminae, which do not exceed 1 inch in thickness, are delineated by extensive de- velopment of secondary calcite. There are also some 6-inch to l-foot beds composed almost entirely of the shells of small brachiopods, but these beds are ex- ceedingly rare. On the north side of the bioherm on Meiklejohn Peak, large cephalopods are well defined in various orientations within its mass. B-232 ' GEOLOGICAL SURVEY RESEARCH 1961 FIGURE 97.1.—-Large bioherm (white area) in the Pogonip group in the southwest slope of Meiklejohn Peak is about 250 feet thick. . ' and E Ninemile formation FIGURE 97.2.—Bioherm (white area) in the Pogonip group southwest of Aysees Peak, Frenchman Lake quadrangle, is 75 feet thick, rests on unit F, and is within lower part of unit G of Johnson and Hibbard (1957, p. 347). SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 The bioherm southwest of Aysees Peak (Nevada grid, central zone, 750,100 feet E. and 773,000 feet N., on Frenchman Lake quadrangle) (fig. 97.2) prob- ably does not exceed 75 feet in thickness and 250 feet in width. It is located high on the east wall of a large canyon. The eroded remains of another bio- herm are readily seen high above the canyon in a side draw 4,000 feet to the north-northeast (Nevada grid, central zone, 751,000 feet E., 776,700 feet N.). A third bioherm buildup may be located west of Oak Spring in the Tippipah Spring quadrangle (Ne— vada grid, central zone, 674,750 feet E., 907,500 feet N.). This area on the west side of Amphitheater Valley has been mapped geologically by Houser and Poole (1960). Ross believes such a mass may be represented by the uppermost exposed unit of the Pogonip as mapped by Houser and Poole (1960, unit Opma, sheet 1) as the upper part of the Pogonip. This unit is composed of exceedingly fine grained homogenous dolomite in which bedding is either massive or very thick. The typical flat bottom and convex top cannot be demonstrated and the presence of a bioherm is therefore uncertain. We have estab- lished the presence of a fauna within the under- lying unit which dates it beyond question as equiva- lent to the Ninemile formation and to unit D of Johnson and Hibbard (1957, p. 346) in a much dolomitized state. The stratigraphic position, homo- , geneous nature of the rock, and aphanitic texture of the dolomite suggest to Ross that this body is also a bioherm. ‘ The localities mentioned here are in an area that is approximately 50 miles from east to west and 30 miles from north to south in the southern part of Nevada. To our knowledge, no algalogist has exam- B—233 ined any of these deposits. We do not know what organisms contributed most to their construction. When detailed studies have been undertaken and completed on these and any other similar structures in the same stratigraphic position it may be possible to reach conclusions concerning their ecologic sig- nificance, and concerning the factors that caused or permitted growth of such impressive structures essentially contemporaneously in a large area of southern Nevada. ' At the present time the economic significance of these buildups seems limited. They are so compact and aphanitic in texture that they probably could not themselves serve as reservoirs for petroleum. Analyses by I. C. Frost and E. J. Fennelly, U. S. Geological Survey, indicate that the single sample tested is composed 93 percent of calcite and 2.65 percent of dolomite. REFERENCES Cornwall, H. R., and Kleinhampl, F. J., 1960, Preliminary geologic map of the Bare Mountain quadrangle, Nye County, Nevada: U.S. Geol. Survey Mineral Inv. Field Studies Map MF~239. Hintze, L. F., 1952, Lower Ordovician trilobites from western Utah and eastern Nevada: Utah Geol. and Mineralog. Survey Bull 48, 249 p., 28 pls. Houser, F. N., and Poole, F. G., 1960, Preliminary geologic map of the Climax stock and vicinity, Nye County, Nevada: U.S. Geol. Survey Misc. Geol. Inv. Map I—328. Johnson, M. S., and Hibbard, D. E., 1957, Geology of the Atomic Energy Commission, Nevada Proving Grounds area, Nevada: U.S. Geol. Survey Bull. 1021—K, p. 333— 384, pls. 32, 33, fig. 57. Nolan, T. B., Merriam, C. W., and Williams, J. S., 1956, The stratigraphic section in the vicinity of Eureka, Nevada: U.S. Geol. Survey Prof. Paper 276, 77 p., illus. 6% 98. SOIL MOISTURE UNDER JUNIPER AND PINYON COMPARED WITH MOISTURE UNDER GRASSLAND IN ARIZONA By R. F. MILLER, F. A. BRANSON, I. S. MCQUEEN, and R. C. CULLER, Denver, Colo. Soil-moisture movement and retention in areas under juniper and pinyon as compared with areas under grass are being investigated at selected sites on the Fort Apache Indian Reservation in Arizona to determine if a net gain of usable water can result from the eradication of juniper and pinyon and re- placement with grass. Soil moisture, temperature, and moisture tension under the three types of plant cover illustrated in figure 98.1 will be measured peri— odically for one year starting early in 1961; prelimi- B—234 FIGURE 98.1.—Photographs of sites being investigated. A, forested area in background, sparsely vegetated area in foreground; B, open grassland. nary measurements were made at these sites near the end of the 1960 growing season (late September). In— formation on the vegetative and aerial cover at each site is given in table 1. TABLE 1.——G1‘ound and aerial cover on each of three sites sampled. Ground cover (percent) . Type of roots Vegetative using water' Bare Bare Aerial cover from the soil soil rocks Mulch Grass Forbs cover Sparsely vegetated . Grass and tree. . . . 75.3 0.2 20.3 4.0 0.3 12 Forested ......... ' . Tree ............. 0 0 100 0 0 700 Grassland ......... Grass ..... p ....... 48 0,8 40.] ‘ 12.2 0.9 25 GEOLOGICAL SURVEY RESEARCH 1.961 Soil moisture, temperature, and moisture tension were determined at 3- to 4-inch increments down through each of the three soils (fig. 98.2). Soil samples were obtained with a 3-inch diameter barrel- type auger.. Part of each sample was placed in a can with a disc of dry pentachlorophenol-treated filter paper, and sealed with elastic adhesive tape. The containers were then stored in a constant tempera- ture chamber for 2 weeks to permit equilibration between the moisture in the soil and the moisture in the paper. Moisture contents of the filter papers and the soil samples were obtained gravimetrically. Soil moisture tension was then determined from a curve that relates the percent of moisture in the paper to soil moisture tension (Gardner, 1936). Soil temperature was determined for each sample as it was taken from the auger hole. Moisture storage in the upper part of the soil columns was greatest under the dense stand of trees TEMPERATURE, IN DEGREES CENTIGRADE SOIL MOISTURE. IN PERCENT 0 10 20 30 40 I.l,|llllrlllrllll IIII ITTI 1,}; 4 l l "Ii-o. ‘ . ‘I' IC DEPTH, IN INCHES U1 o f _ I t _ (\ t 100 III l'lllllll II\ ”III 500 100 50 10 5 3 MOISTURE TENSION, IN ATMOSPHERES EXPLANATION m ,a--—+--o-- ...- ---- 0 ---- o... Grassland Sparsely vegetated Forested FIGURE 98.2.——Soil moisture (M), temperatures, in degrees centigrade (C), and moisture tension (T) under the three different types of plant cover illustrated in figure 98.1. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 (fig. 98.2). Soil moisture under the trees, to a depth of 3 feet, was also retained at lower moisture ten- sions. This is apparently the combined result of lower temperatures from shading, and reduction of evaporation by a thick mulch of fallen foliage. Soil temperatures and moisture tensions at the surface (fig. 98.2) were highest in the site with the least aerial plant cover and decreased as the cover increased. Soil moisture in the grass-root zone (0—48 inches) of the two grassed sites was held at about the same moisture tensions down through the soil profiles. The decrease in moisture tension with depth prob- ably reflects a decrease in the amount of grass roots with depth. The differences in moisture content between soils are apparently the result of differences in soil porosity, rather than differences in water use by the plants. Therefore, differences in water- using capabilities of trees compared to those of grass may be more adequately reflected by moisture-ten- sion data than by soil moisture. Throughout the profiles temperatures tend to de- crease with depth in the two grass-covered soils, but to increase with depth under the trees. Thus, mois- B-235 ture could move down by vapor diffusion in the two grass-covered soils, but would move toward the sur- face under the trees in response to the slight tempera- ture gradients (Philip and Devries, 1957). The accumulations of moisture that are indicated by zones of reduced moisture tension at several depths in each of the grass-covered soils (fig. 98.2), reflect a downward movement of water. This move- ment could be a response to moisture—tension grad- ients as well as to temperature gradients, inasmuch as capillary tension increases below each zone of moisture accumulation. Moisture tensions at depth are within the range through which Philip and Devries (1957) report a maximum of soil-moisture transfer by a combination of capillary tension and moisture diffusion in response to temperature gradients. REFERENCES Gardner, Robert, 1936, A method of measuring the capillary tension of soil moisture over a wide range: Soil Science, v. 43, p. 277—283. Philip, J. R., and Devries, D. A., 1957, Moisture movement in porous materials under temperature gradients: Am. Geo- phys. Union Trans, v. 38, p. 222—232. 5% 99. CORALS FROM PERMIAN ROCKS OF THE NORTHERN ROCKY MOUNTAIN REGION By HELEN DUNCAN, Washington, D. C. The seeming absence of corals in the Permian rocks of the northern Rocky Mountain region has been a faunal anomaly to stratigraphic paleontolo- gists concerned with studies of the Phosphoria, Park City, and Shedhorn formations. Some of the sedi- mentary environments that prevailed in the region through much of Permian time quite obviously were unfavorable for corals, but it is difficult to explain why these organisms should not be present in carbonate facies that supported a fairly prolific fauna of bryozoans and articulate brachiopods. Solitary rugose corals normally occur in such faunal associations, and representatives of the group are found, at least sporadically, in temporally equivalent strata to the west and south. The many reports of Girty on Permian faunas of the region contain no references to corals; moreover, during a period of about 15 years, I had seen no corals in Permian collections made by US. Geologi- cal Survey geologists from the northern Rockies. It is therefore worthy of note that E. L. Yochelson’s current investigations of faunas from the Phos phoria, Park City, and Shedhorn formations ha‘ disclosed the presence of horn corals in 4 collectio" 5 of which at least 2 are certainly Permian. EA- Cressman’s discovery of colonial rugose coralin strata assigned to the lower member (suppodly Grandeur equivalent) of the Park City formatn 1n Lemhi County, Idaho, extends our data on th geo- graphic distribution of a coral zone that isfairly widely developed in western Lower Permia FOCkS (Wolfcamp and early Leonard equivalents) The material presently available is meger and very poorly preserved, .but it is adequate 0 demon- B—236 strate that corals are not entirely lacking in the Permian of the region. It is hoped that future col- lecting will provide specimens that can be used for systematic description. Known occurrences are re- viewed in this paper. MONTANA Corals were found in two collections from tongues of the Park City that extend into the Snowcrest Range in southeast Beaverhead County, Mont. A mold of a calyx of a small horn coral was collected about the middle of the Franson tongue on Sawtooth Peak (USGS 10854—PC). The rock is composed largely of organic debris, and the coral was reworked to some extent but presumably came from essentially contemporaneous deposits. This occurrence is defin- itely Permian. Two fragments of small horn corals in fine-grained siliceous rock were collected from beds considered in the field to be about the middle of the Grandeur tongue of the Park City on Hogback Mountain (USGS 11674—PC). Sections reveal that one of the specimens is probably Lophophyllidium. The other is a zaphrentoid coral too altered for generic identi- fication. According to Yochelson (oral communica- tion, 1961), the beds from which the collection came probably are older than the type Grandeur member. The corals are not of kinds that can be safely used to differentiate Permian from Pennsylvania. WYOMING A collection (USGS 12201—PC) from the base of the lower part of the Shedhorn sandstone on Tosi C eek, G Ve t‘e uad an 1e, Sublette Count , i _ . r ros n l q r g y i The septa are pers1stent and relatlvely long, and Wyo., provided a mold of a small horn coral, which I suspect belongs to the lophophyllidid group. There is no good evidence from the associated fauna that he beds in question are Permian. IDAHO Three minute horn corals of indisputable Permian a, were discovered in a collection from a limestone lelnear the middle of the Rex chert member of the Ph‘phoria formation. This lot (USGS 19532—130) Wasullected on the South Fork of Sage Creek, Stew- GEOLOGICAL SURVEY RESEARCH 1961 art Flat quadrangle, Caribou County, Idaho. The corals were obtained when rock from this locality was dissolved in acid. These silicified specimens have slightly curved ceratoid coralla, the largest being about 10 mm long, with rather conspicuous longi- tudinal ribbing. Evidence of internal deposits (septa, tabulae, etc.) is lacking, possibly having been destroyed by the acid treatment. E. R. Cressman found colonial rugose corals at three localities in the Morrison Lake quadrangle, Lemhi County, Idaho. The material is recorded as coming from the lower part of the Park City forma- tion, a unit that presumably would now be called the Grandeur member. The corals are replaced by silica, and one cannot be certain that all critical internal structures are preserved. Specimens from two of the localities, one (USGS 19302—PC) 66 feet above the base of the Park City in the Hawley Creek sec- tion and the other (USGS 19303—PC) from about the middle of the supposed Grandeur member, are dis- sepimented phaceloid forms. The corallites seem to have relatively short septa and slightly domed tabu- lae. Most individuals show no evidence of columel- lae or axial structures; however, traces of delicate axial rods and slightly more complicated structures were seen in a few transverse sections. It is impos- sible to tell whether axial structures originally were present in all corallites and largely destroyed in the course of replacement, or whether these corals repre- sent a diphyphyllid variant of some lithostrotionoid genus. Another genus of dissepimented phaceloid coral was collected 185 feet above the base of the Park City in the Hawley Creek section (USGS 19304—PC). most of the corallites exhibit an arachnoid axial structure. This form is related to Heritschioides. The colonial corals obtained from the lower part of the Park City of the Morrison Lake quadrangle i suggest that the beds involved are pre-Kaibab in age and somewhat older than the Grandeur member of the type area in the Wasatch Mountains. Similar , corals occur rather widely in the Great Basin, com- monly in the zone of Pseudoschwagerina and primi- tive Parafusulina. ’X‘ SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 100. B—237 OCCURRENCES OF THE PERMIAN GASTROPOD 0MPHALOTROCHUS IN NORTHWESTERN UNITED STATES By ELLIs L. YOCHELSON, Washington, D. C. Omphalotrochus is a guide to the lower part of the Lower Permian (Yochelson, 1954) occurring in the type Wolfcamp formation and its equivalents. More than half a century ago George H. Girty (1905a, p. 20) wrote of an American “0mphalotrochus zone,” and Knight (1940) discussed the stratigraphic im- portance of the genus in Russia. The genus is a common, widely distributed fossil in southwestern United States (Yochelson, 1956). It is also widespread in northwestern United States but has rarely been collected, possibly because the significance of this gastropod has not been empha- sized. Localities where it has been found are here documented. Because Omphalotrochus is easily identified in the field it has a high potential useful- ness in stratigraphic investigations. _ Omphalotrochus is large: specimens are seldom less than one inch across the base and may be up to 6 inches across. The base is flattened and bears a large umbilicus with nearly vertical walls. Shells are low spired, with few whorls and with a fairly simple whorl profile. Incomplete specimens and cross sections can be identified as to genus with a high degree of confidence. All known American species are illustrated by Yochelson (1956). Aper- tural and basal views of representative specimens are shown in figure 100.1. Occurrences of Omphalotrochus in Arizona, Kan- sas, New Mexico, Oklahoma, and Texas are given by Yochelson (1956), and no additional records from these states are included in this review. “Omphalo- trochus” as used by Girty for specimens from the Park City, Phosphoria, and “Embar” formations has been assigned to the genus Babylonites Yochelson, which is excluded. Numbers in parenthesis refer to the permanent register of U. S. Geological Survey fossil localities. South Dakota.—In 1957, V. R. Wilmarth collected Om’phalotrochus near Minnekahta, S. Dak., in the SW14 sec. 27, T. 6 S., R. 4 E. Fossils were collected from the steep west wall of the unnamed canyon just east of Argyle Canyon, about 1.25 miles north of the Custer-Fall River County line. Omphalotrochus occurs in two zones: one is a red; fine- to medium- grained sandstone, 59 to 22 feet below the top of the Minnelusa sandstone (19152—PC) ; the second is a limestone breccia 96 to 84 feet below the top of the formation (USGS 19153—PC). Specimens are rare and too incomplete to be specifically identified. Wyoming—Thompson and Thomas (in Thomas, Thompson, and Harrison, 1953, p. 19) cite an identi- fication by J. Brookes Knight of Omphalotrochus collected in 1940 by H. R. McCurdy from the upper part of the Casper formation near Farthing, Wyo. In 1959, Omphalotrochus wolfcampensis Yochelson was collected by the writer in abundance from a cherty limestone on the north side of a branch of Chugwater Creek in the NEfiSWfiSEl/g sec. 34, T. 19 S. 70 W., Laramie County, Wyo., as determined from Harrison’s unpublished map (USGS 19820- PC). Thomas, Thompson, and Harrison (1953, pl. 9) indicate that Omphalotrochus occurs about 450 feet below the top of the Casper formation. In 1922, C. R. Longwell and W. W. Rubey collected a specimen 70 feet below the top of the Minnelusa sandstone, in Fawcett Canyon, Newcastle quad- rangle, Weston County, Wyo., (USGS 4397—PC). The specimen may be 0. wolfcampensis, but addi- tional material is needed to verify the specific identi- fication. Utah—Girty (1905b, p. 391) listed Omphalotro- chus in a fauna collected by him and J. M. Boutwell, in the Bingham mining district. His specimens came from the “upper portion of limestone,” now recog- nized as the upper part of the Oquirrh formation, one-eighth mile west of the Dalton and Lark mine, Salt Lake County, Utah (USGS 2555 green series). In 1959, the writer, R. J. Roberts and E. W. Tooker, relocated this locality in Cooper Canyon, west of Lark, Utah, on the extreme edge of the Bingham Canyon quadrangle (USGS 18892—PC). The speci- mens we obtained were identified as 0. wolfcam- pensis. In 1958, Roberts and Tooker collected the same species in the upper part of the Oquirrh at an elevation of 5,700 feet in Black Rock Canyon, NEIA, sec. 30, T. 1 S., R. 3 W., Garfield quadrangle, Tooele County, Utah, (USGS 18486—PC, 18893—PC). Girty (in Nolan, 1935, p. 38) listed Omphalotro- chus sp., from the “western facies” of the Oquirrh formation about 1/3 mile NNE of the AB Claim on the west side of Dutch Mountain in the Gold Hill mining district (USGS 6332—PC). From the “cen- tral facies” of the Oquirrh, he listed Omphalotrochus sp., occurring just west of the intersection of the B—238 FIGURE 100.1.—Apertural and basal views of representative specimens of Omphalotrochus, approximately natural size. center spur in Sheridan Canyon with the main ridge line (USGS 6362—PC), and Omphalotrochus? sp. from the lower slopes of the center spur in Sheridan Canyon (USGS 6360—PC). The specimens from the first two localities are 0. wolfcampensis; that from the third locality is indeterminate. All localities were considered to be from the “higher Pennsylvanian” as used by Girty, which now refers to the lower part of the Permian. Omphalotrochus may occur in the Silver Island Range of northwest Utah, but specimens are incom- plete and locality data unsatisfactory. In faunal lists, Girty (in McKnight, 1940, p. 34) reports Omphalo- trochus? sp. from the Rico formation in San Juan County. Unfortunately, the specimen or specimens could not be found in the collection (USGS 6036—PC), and this report cannot be substantiated. Nevada.—Although this genus has been reported informally as being widespread and locally abundant, a brief examination of the many Survey collections from this State yielded Omphalotrochus from only three areas. To the best of the writer’s knowledge these occurrences have not been cited heretofore. In 1900, F. B. Weeks collected a large specimen from the southeast slope of Hamels Peak, Egan Range, 17 miles south of Ely in the gully south of Ice Creek (USGS 2702 green series); presumably GEOLOGICAL SURVEY RESEARCH 1961 this is from the Carbon Ridge formation. Girty identified the specimen in the collection as O. whit- neyi. This first use of the specific name for a speci- men far from the type area in California probably was based on the large size of the shell, here con- sidered to be specifically indeterminate. In 1923, C. R. Longwell’s party, mapping in the Las Vegas quadrangle, collected specifically indeter- minate Omphalotrochus f1 om 250 feet of “Pennsyl- vanian limestone and sandstone” at the top of Wil- liams Peak in the Spring Mountains (USGS 6484- PC). Excellent 0. wolfcampensz's was collected in the quadrangle, but the locality data are poor; the specimens are from the first 30 feet of black dense limestone just below the “Supai” formation (USGS 6473—PC). Presumably both collections are from the upper part of the Bird Spring formation of current terminology. A single small specimen of O. wolfcampensis was collected by H. G. Ferguson and J. S. Williams in 1940 in float from the Antler Peak limestone. It was obtained on the southeast slope of Antler Peak, near the top, in the SE14 sec. 33, T. 31 N., R. 43 E., Antler Peak quadrangle (USGS 8730—PC). Idaho—In 1958, W. J. Carr and D. E. Trimble collected two specimens from approximately sec. 5, T. 12 S., R. 32 E., about 7 miles south of the south- west corner of the Arbon quadrangle on the west face of the Deep Creek Mountains, Power County, Idaho. The first specimen (USGS 19114—PC) is 0. wolfcampensis; the second (USGS 19116—PC) is less well preserved and is specifically indeterminate. Carr and Trimble obtained one other specimen, which probably is O. wolfcampensis, 890 feet below the top of a measured section, ending at the top of peak 7484, Deep Creek Mountains, on the east side of the north fork of Sawmill Canyon in the NW1/4 sec. 19, T. 9 S., R. 32 E., Rockland quadrangle, Power County, Idaho (USGS 19105—PC). Oregon—In 1908, J. T. Pardee submitted several collections from the Sumpter quadrangle to George H. Girty for identification. One collection from along the railway about 2.75 miles south of Sumpter, Baker County, Oreg., (USGS 19549—PC) contains fusul- inids, echinoid spines, Composite? sp. indet., and a poorly preserved Omphalotrochus. California—A review of old collections has brought to light additional specimens of Omphalo- trochus, including some from the Redding quad- rangle (Diller, 1906). Some of the specimens are topotypes of O. whitneyi (Meek), the type of the genus, but also the least well known species. Because some Omphalotrochus undergo pronounced ontogen- SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 etic change, there has been a question of the rela- tionship of O. whitneyi to better known forms. In- vestigation of all California specimens may result in revision of the limits of several species. REFERENCES Diller, J. S., 1906, Description of the Redding folio [Cali- fornia]: U.S. Geol. Survey Geol. Atlas, Folio 138. Girty, G. H., 1905a, The relations of some Carboniferous faunas: Washington Acad. Sci. Proc., vol. 7, p. 1—26. 1905b, Paleontology, p. 387-393 in Boutwell, J. M., Economic geology of the Bingham mining district, Utah, with a section on areal geology, by Arthur Keith, and an introduction on general geology, by S. F. Emmons: U.S. Geol. Survey Prof. Paper 38, 413 p., 49 pls. Knight, J. B., 1940, Are the “Omphalot’rochus beds” of the U.S.S.R. Permian?: Am. Assoc. Petroleum Geologists Bull., v. 24, p. 1128—1131, with additional discussion by C. O. Dunbar and R. B. King. 101. B—239 McKnight, E. T., 1940 [1941] Geology of area between Green and Colorado Rivers, Grand and San Juan Counties, Utah: U.S. Geol. Survey Bull. 908, 147 p., 13 pls. Nolan, T. B., 1935, The Gold Hill mining district, Utah: U.S. Geol. Survey Prof. Paper 177, 172 p., 15 pls. Thomas, H. D., Thompson, M. L., and Harrison, John W., 1953, Stratigraphy of the Casper formation, p. 1—14, pl. 9, in Fusulinids of the Casper formation of Wyoming: Wyo- ming Geol. Survey Bull. 46. Thompson, M. L., and Thomas, H. D., 1953, Systematic Paleontology of fusulinids from the Casper formation, p. 15—56, pls. 1—8, in Fusulinids of the Casper formation of Wyoming: Wyoming Geol. Survey Bull. 46. Yochelson, E. L., 1954, Some problems concerning the distri- bution of the late Paleozoic gastropod Omphalotrochus: Science, v. 120, p. 233—234. 1956, Permian Gastropoda of the southwestern United States: 1, Euomphalacea, Trochonematacea, Pseudo- phoracea, Anomphalacea, Craspedostomatacea, and Platyceratacea: Am. Mus. Nat. History Bull., v. 110, art. 3, p. 173—276. 51‘ PENNSYLVANIAN ROCKS IN SOUTHEASTERN ALASKA By J. THOMAS DUTRO, JR., and RAYMOND C. DOUGLASS, Washington, D. C. The apparent scarcity of marine rocks of Pennsyl- vanian age in Alaska has been a stratigraphic anom- aly that has puzzled geologists for nearly 50 years. In his summary of the geology of Alaska, P. S. Smith (1939, p. 26) emphasized the importance of a lime- stone at a single locality in Soda Bay, Prince of Wales Island, concluding: More detailed examination of the locality will be required before this determination (Pennsylvanian?) can be regarded as definite, but should it be confirmed by that study it would be of special importance, because it would prove the presence of Pennsylvanian rocks, which are unknown not only else— where in southeastern Alaska but in any other part of the Territory. PRINCE OF WALES ISLAND Material collected from this locality is not suf- ficiently diagnostic to establish the precise age of the beds in question. A restudy of the coelenterates by Helen Duncan, the gastropods by Ellis Yochelson, and the foraminifers by Douglass has been incon- clusive. The fossils could represent a lower Namur— ian fauna (highest Mississippian equivalent) which might reasonably occur above the Upper Mississip- pian Gigantoproductus beds, present also at Soda Bay. On the other hand, the strata of doubtful age could correlate with the Lower Pennsylvanian beds with Gastriocems, which crop out in Trocadero Bay, just to the north on the west coast of Prince of Wales Island (Gordon, 1955). Fusuline foraminifers were listed in several col- lections from southeastern Alaska by G. H. Girty in Buddington and Chapin (1929, p. 112—115). Girty stated that the evidence, although not unequivocal, suggested a Mississippian age. L. G. Henbest (writ- ten communication, 1936) called Girty’s attention to the significance of the Fusulinellas in a collection from northern Kuiu Island; this information, to- gether with the evidence from crinoids and a reevalu- ation by Girty of the rest of the fossils, was the basis for Kirk’s (1937a, p. 110) Pennsylvanian age assign- ment. Our detailed reexamination of this collection has resulted in a definite Middle Pennsylvanian age determination. Field geologists should be alert to the possibility that Pennsylvanian rocks are more widespread in the area than hitherto assumed. Further study is needed to determine the areal extent of these rocks B—240 134°30’ 134° 57° O SMILES ISLAND FIGURE 101.1—Locality of Middle Pennsylvanian collection (USGS 5443—PC) near the head of Saginaw Bay, northern Kuiu Island, southeastern Alaska. and their precise stratigraphic relations with the Mississippian and Permian strata. KUIU ISLAND LOCALITY Collection 5443—PC came from a 40-foot thick bed of limestone, intercalated in a series of interlayered chert, quartzite, and chert-bearing limestone, at the northwest end of the long island near the head of Saginaw Bay, Kuiu Island (figure 101.1). Litho— logically similar rock sequences are relatively Wide- spread in southeastern Alaska at the top of what was considered Mississippian by Buddington and Chapin (1929, p. 110), and‘Pennsylvanian fossils should be sought in this part of the section during future field investigations. Foraminifera identified in this collection (5443— PC : f2277 : Buddington field No. 930) are: Climacammz'na sp. endothyrid foraminifer, undet. Tetrataxis sp. Bradyina sp. Nummulostegina ? sp. Fusulinella spp. Probably two species of Fusulinella are repre- sented. One is a loosely coiled form with plane septa and small, nearly symmetrical chomata. This form resembles F'. bocki Moller, 1878. It is smaller and shows less fluting of the septa than is shown by 56"45’ GEOLOGICAL SURVEY RESEARCH 1961 forms referred to this species by Forbes (1960) from Spitzbergen. The species is quite like—and may be referable to—Fusulinella jamesensis Thompson, Pit- rat, and Sanderson (1953), described from British Columbia. The other species is more tightly coiled, fusiform to elongate, and has asymmetrical chomata extending along the septa and floors toward the poles, some- what resembling Wedekindellind. Fusulinella iowen- sis Thompson (1936) is similar in many ways to the Alaskan specimens. The foraminiferal fauna indicates an early Middle Pennsylvanian age, possibly an Atoka equivalent. Although Girty prepared a long fossil list from this locality, many of the forms either were not de- termined as to species or were listed as new. A re- study of the collection has resulted in the identifi- . cation of the following larger fossils: Clithrocrinus pyriformis Kirk Synbathocrinus sp. Delocm’nus sp. Cyathaxom'a sp. aulophylloid corals, genus undet. 'horn coral, undet. Fenestella sp. “Batostomella” sp. Cystodictya sp. rhomboporoid bryozoan, indet. multifoliate fistuliporoid, undet. Leioclema ? sp. Petrocmnia? sp. Rhipidomella aff. R. nevadensis (Meek) Schizophoria aff. S. resupinoides (Cox) Derbyia? sp. Chonetes sp. Chonetina? sp. (compare C. flemingi crassir- adiata Dunbar and Condra) Jm'esan'ia aff. J. ovalis Dunbar and Condra Krotovia? sp. Linom‘oductus (sensu st7’ict0) spp. dictyoclostid brachiopod, genus indet. “Margim’fem” sp. Spirz'fer aff. S. rockymontanus Marcou N eospim‘fer sp. Spiriferella aff. S. texana (Shumard) Martinia? sp. Composita sp. (small) Crum’thym's sp. th‘codothym’s? sp. Stenoscisma sp. Hustedz'a sp. Rhynchopom cf. R. magnicosta Mather SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 Crenis'pirifer? sp. Punctospirifer? sp. Dielasma spp. Aviculopecten sp. Schizodus sp. Platyceras sp. cf. Straparollus (Euomphalus ?) savagei Knight euomphalacean gastropod, indet. pleurotomariacean gastropod, indet. bellerophontacean gastropod, indet. ostracodes, indet. This revised list of megafossils clearly indicates a Pennsylvanian age. Several species to which the Alaskan fossils have been compared are restricted to the lower part of the Pennsylvanian, insofar as their distribution is known at present. For example, Rhipidomella nevadensis (Meek), Chonetina flemingi crassimdiata Dunbar and Condra, Spirifer rocky- montanus Marcouthynchopom magnicosta Mather, and Straparollus savagei Knight are all compatible with the early Middle Pennsylvanian age assignment suggested by the fusulines. The other fossils do not conflict with such an assignment. REFERENCES Buddington, A. F., and Chapin, T., 1929, Geology and mineral deposits of southeastern Alaska: U.S. Geol. Survey Bull. 800, 398 p., 22 pls., 3 figs. B—241 Dunbar, C. 0., and Condra, G. E., 1932, Brachiopoda of the Pennsylvanian system in Nebraska: Nebraska Geol. Sur- vey Bull. 5, second series, 377 p., 44 pls., 25 figs. Forbes, C. L., 1960, Carboniferous and Permian Fusulinidae from Spitzbergen: Palaeontology, v. 2, pt. 2, p. 210-225, pls. 30—33, text fig. Gordon, Mackenzie, Jr., 1955, Alaskan Carboniferous gonia- tites [abstract]: Geol. Soc. America Bull., v. 66, no. 12, pt. 2, p. 1565. Kirk, E., 19373, Clistocrinus, a new Carboniferous crinoid genus: Washington Acad. Sci. Jour., v. 27, no. 3, p. 105— 111, figs. 1—8. 1937b, Clithroci'inus, new name for Clistocrimts Kirk: Washington Acad. Sci. Jour., v. 27, no. 9, p. 373—374. Knight, J. B., 1934, The gastropods of the St. Louis, Missouri, Pennsylvanian outlier: VII. The Euomphalidae and Platyceratidae: Jour. Paleontology, v. 8, no. 2, p. 139—166, pls. 20—26. Moore, R. C., and others, 1944, Correlation of Pennsylvanian formations of North America: Geol. Soc. America Bull., v. 55, p. 657—706. Muir-Wood, H., and Cooper, G. A., 1960, Morphology, classifi- cation and life habits of the Productoidea (Brachiopoda) : Geol. Soc. America Mem. 81, 447 p. 135 pls., 8 figs. Smith, P. S., 1939, Areal geology of Alaska: U.S. Geol. Survey Prof. Paper 192, 100 p., 18 pls., chart. Thompson, M. L., 1936, Pennsylvanian fusulinids from Ohio: Jour. Paleontology, v. 10, no. 8, p. 673—683, pls. 90, 91. Thompson, M. L., Pitrat, C. W., and Sanderson, G. A., 1953, Primitive Cache Creek fusulinids from central British Columbia: Jour. Paleontology, v. 27, no. 4, p. 545—552, pls. 57, 58. é? GEOPH YSI CS 102. POISSON’S RATIO OF ROCK SALT AND POTASH ORE By R. E. WARRICK and W. H. JACKSON, Denver, Colo. Work done in cooperation with the U.S. Atomic Energy Commission for the Plowshare Program, Project Gnome Measurements of elastic constants of rock salt and potash ore of the Salado formation of Permian age (Dunlap, 1951) were made in the mine of the U.S. Potash Co. near Carlsbad, N. Mex. The same con- stants were measured on samples in the laboratory, and Poisson’s ratio determined by the difi'erent methods was found to differ. The writer is grateful for help given in the field by the management and staff of the U.S. Potash Co. Iii-place measurements.—In-place measurements of elastic constants consisted of determining the velocities of compressional and shear waves in a B-242 pillar of rock (Roller and others, 1959). Pillars rep— resenting the potash rock and the salt rock were se- lected. Four sites in the same horizontal plane along the pillars were chosen for instrument locations, and a matching set of four positions was surveyed di- rectly opposite from the first set of points on the other side of the pillar. The potash pillar was 38 feet wide and 150 feet long. The salt pillar was 25 feet wide and more than 300 feet long. The source of vibrations was a small hammer that was struck against a steel block fastened ,to the rock wall with an expansion bolt. Two barium- titanate accelerometers were fastened on the opposite side of the pillar with a small expansion bolt. One was mounted with its principal axis of sensitivity perpendicular to the wall, and the other with its axis parallel to the wall. The signals from the accelerom- eters were amplified with a wide-band preampli- fier, and were displayed on a calibrated oscilloscope. Permanent records were made by photographing the oscilloscope screen. The instant the hammer struck the anvil, the oscilloscope sweep began mov- ing across the screen at a constant rate. The energy arriving through the pillar was detected by accel- erometers and the signal that was produced was pre- sented on this time base. ‘ The first energy arriving at the detectors was compressional. The shear energy arrived somewhat later and could be distinguished by the change of the wave form. The velocities of both waves were de- termined from transit times of the waves trans- mitted through the pillar. All elastic constants can be derived from compressional and shear velocities and the density of the rock (Howell, 1959, p. 204). Density was determined from large samples taken from the pillars. Spectrographic analyses of the samples, made by T. Botinelly, showed the salt was 90 to 93 percent NaCl, ani included a trace of sylvite (KCl). The potash was 95 percent sylvite, and included traces of halite and polyhalite. Laboratory measurements.-—Samples from the mine pillars were sent to two laboratories for de- termination of the elastic constants. For one set the constants were measured by ultrasonic-pulse methods (Mason, 1958, p. 95) by E. C. Walker in the Geological Survey laboratories in Washington, DC. For the other set the constants were measured by uniaxial compression tests through the courtesy GEOLOGICAL SURVEY RESEARCH 1961 TABLE 1.—Poisson’s ratio determined by diflerent techniques In-place test Ultrasonic test Unconfined uniaxial compression test Type of rock and location of test or sample 600 1,000 lb. within pillar Standard Standard lb. per Sq. in. 1,600 Ratio deviation Ratio deviation per ____________ _ lb. per sq Standard sq. in in Ratio deviation Potash pillar: North ....... 0.32 0.03 0.35 0.05 0.16 0.17 0.02 0.23 Central. . . .. .32 .01 .24 .05 .............................. South ....... .29 .01 .31 .05 .............................. Salt pillar: North....,.. .27 .03 .15 .04 0.14 0.19 .02 0.27 South ....... .24 .01 .18 .04 ............................. of O. J. Olson in the Bureau of Reclamation labora- tories in Denver, Colo. Comparison of results—Values of Poisson’s ratio determined by the three methods are shown in table 1. Poisson’s ratio was selected for comparison be- cause it is derived more directly from the measured data than other elastic constants. The values listed are mean values of the several determinations. The in-place and ultrasonic methods yielded values of Poisson’s ratio that are in fairly good agreement for potash. Internally disrupted or slightly weathered samples may be the cause of lower values determined by the ultrasonic method for the salt. The salt pillar was several years older than the potash pillar, and the salt samples could not be taken as deep within the pillar as the potash samples. Unconfined uniaxial-compression determinations did not agree With in-place and ultrasonic determina- tions of Poisson’s ratio for potash. The compression- test values approached the in-place values as the stress increased for both potash and salt samples. Exact correspondence of Poisson’s ratio deter— mined by the different techniques could not be ex- pected because of the variation of elastic constants with the method of measurement. The in-place method should be preferable because the problem of altering properties through sampling is less severe. REFERENCES Dunlap, John C., 1951, Geologic studies in a New Mexico potash mine: Econ. Geology, v. 46, no. 8, p. 909—923. Howell, B. F., Jr., 1959, Introduction to geophysics: New York, McGraW-Hill Book Co. Mason, Warren P., 1958, Physical acoustics and the properties of solids: Princeton, D. Van Nostrand Co., Inc. Roller, J. C., and others, 1959, Seismic measurements by the US. Geological» Survey during the pre-Gnome high- explosive tests: A preliminary summary: U.S. Gem. Survey open-file report. ’5? SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 103. B-243 FREQUENCY CONTENT OF SEISMOGRAMS OF NUCLEAR EXPLOSIONS AND AFTERSHOCKS By S. W. STEWART and W. H. DIMENT, Denver, Colo., and Washington, D. C. Work done in cooperation with the Advanced Research Projects Agency, Department of Defense The frequency content of seismic waves is a funda- mental part of the data obtained from seismograms. Reported methods for studying the frequency spec- tra of seismic waves have ranged from simple mea- surements of apparent frequency along the seismo- gram to elaborate cross- and auto-correlation calculations by digital or analog computers. Most of these studies have necessarily been concerned with the frequency spectrum of fairly large parts of the seismogram. However, some investigators have re- ported a technique of presenting a continuously changing frequency spectrum as a function of time. This technique, called here the moving-spectrum method, essentially is one of calculating the frequency spectrum of relatively small parts of the seismogram, and presenting the frequency spectra so calculated as a function of time. Ewing and others (1959) have used seismograms recorded on magnetic tape, and appropriate analog methods, to present moving- spectrum representations of seismograms of earth- quakes and explosions. In this paper results are given for the calculation of moving-spectrum data by digital methods. R. G. Henderson and H. W. Oliver helped in set- ting up the digitizing program. We are particularly indebted to R. G. Henderson for helping us in de- signing the method of analysis, and to Walter Ander- son for writing the program. F. M. Valentine as- sisted in the seismogram digitizing and plotting of the data. CALCULATION OF MOVING-SPECTRUM DATA Seismograms used in this study were taken from larger groups used in studies of nuclear explosions in Nevada (Diment and others, 1961), and after- shocks of the Hebgen Lake, Mont, earthquake of August 1959 (Stewart and others, 1960). For these seismograms, frequencies were chiefly in the range 2 to 10 cycles per second, and the main part of the seismic energy had traveled past the recording sta- tion in a few tens of seconds. The frequency content of parts of seismograms was calculated by the Fourier transform method on a Datatron 220 digital computer. The seismogram trace was prepared for input into the computer by digitizing it at intervals of 10 milliseconds, using a semi-automatic seismogram digitizer developed under the direction of Donald Rock, with assistance from E. C. Moore. Frequency spectra were calcu- lated for l-second segments along the trace, with the 1-second segments overlapping by 1/2 second. For example, spectra were calculated that covered the intervals 10.0—11.0 seconds, 10.5—11.5 seconds, 11.0—12.0 seconds, etc. Although the time associated with the spectrum covering a 1-second interval of the trace has been taken to be the time at the mid- point of the interval, it must be realized that the time of arrival of any frequency component is no more accurate than the length of this interval, or approximately : 1/2 second. Referring to figures 103.1, 103.2, and 103.3, the spectra so computed are then plotted in the form of a contour map, with the X-axis representing time along the seismic trace, the Y-axis representing fre- quency, and the values of the contours representing the amplitude components of the Fourier frequency spectrum calculation, referred to a maximum Fourier ' amplitude component of 100. Fourier amplitude components were calculated for the frequency range of 0 to 20 cycles per second, at intervals of 1/g-cycle per second. The Fourier amplitude components were not corrected for the frequency response character— istics of the seismic recording system. Because the seismic recording system has a peak response at about 3 cycles per second (Diment and others, 1961, p. 205, curve B), the effect of this is to make the Fourier amplitude components progressively smaller than they should be, for progressively higher fre- quencies. However, the qualitative nature of the contour map is preserved. Although a smaller con- tour interval adds greatly to the usefulness of the data, the large contour interval used in these figures is sufficient to bring out the main features of the method. T I I I I I I I I I I | I I ' I I I I I 20— g — - o 16— _ 8 I I m ' I V —I E 14’— Q I” n- F I Zfi/‘ID A U) 5 12— J , — 8 ~ ' i — Q I 10— % ’ I \ _ E ’ (1:) (ID (>3- ~ _ E 8— _ _ Io _ g Cs 61 m 6- _ I“ — M — 4—- ’0”\/\ — " ,0 I0 Q20 30 O’\/\_, " o '5 2— v COM (easel / are — WWI TRAVEL TIME, IN SECONDS 10 12 14 16 18 20 22 24 26 28 I I J I I I I I I I | I I I I l I I I I I | I I I 7 6 5 4 3.5 3 2.5 2.2 GROUP VELOCITY, IN KILOMETERS PER SECOND FIGURE 103.1.—Moving-spectrum analysis, and tracing of seis- mogram for vertical component of air nuclear shot SMOKY. Distance from shot to station is 58.8 kilometers. Contours are in percent of largest Fourier amplitude component present. RESULTS The seismogram for air nuclear shot SMOKY (fig. 103.1) shows, just before the arrival of the ini- tial P—wave at 10.6 seconds, a background of con- tinual noise. The moving spectrum analysis indicates that this microseiSmic noise is confined to a rela- tively narrow frequency band centered at about 12 'cycles per second, and that the amplitude of this noise is about 1 percent of the maximum amplitude recorded on the seismogram. The arrival of the initial P-wave coincides with a noticeable broaden- ing of the frequency spectrum, both above and below this microseismic band. The seismogram also shows a large-amplitude . transient event with an arrival time of 13.4 seconds. The spectrum beginning at 13 seconds shows a noticeable broadening, the 10-percent contour lines overing the spectrum- from 2 to 7 cycles per second, and the 1-percent contour lines extending up to 16.5 GEOLOGICAL SURVEY RESEARCH 1961 cycles per second. Taking into account the time delays associated with the shot and station locations, the observed time of arrival of this transient event is only 0.2 seconds earlier than that calculated for a P-wave reflection from the base of crustal material having a velocity of 6.15 km per sec in this region (Diment and others, 1961). The good agreement between the observed event at 13.4 seconds and the calculated time of 13.6 seconds suggests that the ob- served spectral broadening beginning at 13 seconds may be related to this reflection event. The effect of reciprocal spreading (Ewing and others, 1959) may account for the broad-band nature of these short- lived events. Similar broadenings of the spectrum, beginning at 17 and 191/3 seconds, are suggested in figure 103.1. These may also be caused by the appearance of short-lived but coherent transients superposed upon I I I I I I I I I I ' I I I I I I I I I 20— — 6“ x“ d\“ - I? <3; d. - 18~ / . Q’be — 9 “ 69 9% ‘ 8 16* . IL - a — L? . E 14~ — o- g m 1 B 12— _ o >- _ 0 _ g 10* _ >’ E _ o .2. 8— 1 3 o — 1 LIJ E 6— - z \3 .33 . — 5 5 2 C“ 0‘1 @f I‘ ’I'W/om rv—va. Kim TRAVEL TIME, IN SECONDS 12 14 16 18 2O 22 24 26 28 30 L I I I | L I I I I 1 I l I | J I I I I | I I I | | I I 6 5 4 3.5 3 2.5 2.2 2 GROUP VELOCITY. IN KILOMETERS PER SECOND FIGURE 103.2.——Moving-spectrum analysis, and tracing of seis- mogram, for vertical component of underground nuclear shot BLANCA. Distance from shot to station is 61.2 kilometers. Contours are in percent of largest Fourier amplitude component present. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 20 18 16— 14— 12— 10“ APPROXIMATE TRAVEL TIME, IN SECONDS 8101214161820222426 llllllllilllilllill FREQUENCY, IN CYCLES PER SECOND I I I T l I I I I 1 6 5 4 3 2.5 2 1.5 APPROXIMATE GROUP VELOCITY, IN KILOMETERS PER SECOND FIGURE 103.3.—Moving—spectrum analysis, and tracing of seis- mogram, for vertical component of an aftershock of the Hebgen Lake, Mont., earthquake of August 1959. Dis- tance from focus to station is about 37 kilometers. Contours are in percent of largest Fourier amplitude component present. the relative “noise” of the seismic trace, but it seems reasonable to associate the broadening of the spec- trum at 191/; seconds with the onset of the large- amplitude surface waves at this time. Because the seismic traces on figures 103.2 and 103.3 were free of noise, spectrum analyses were calculated only from the beginning of the first ar- rival of seismic energy. The seismogram on figure 103.2 shows a large-amplitude pulselike event arriv- ing at about 13.3 seconds, and a noticeable broaden- ing of the spectrum beginning at 13 seconds. The observed time of this event is only about 0.2 seconds earlier than that calculated for a P-wave reflection from the base of crustal material having a velocity of 6.15 km per sec in this region. Although the complex nature of the near-surface geology in Nevada and the relatively high frequencies B—245 recorded on these seismograms would complicate greatly the appearance and interpretation of seismic surface waves, it was hoped that the dispersive char- acter, if any, of the surface waves could be displayed by this moving-spectrum technique. The best exam- ple of dispersed waves found is shown on figure 103.2, corresponding to group velocities in the range 2.3 to 2.6 km per sec, and frequencies in the range 2 to 3 cps. The dispersion is reversed, the higher frequencies having the higher group velocities. It is instructive to compare the envelopes of the 10-percent contour lines for the moving-spectrum presentation. For the air and underground nuclear shots (figs 103.1 and 103.2) the main part of the seismic energy is below 10 cycles per second, and the envelope of the 10-percent contour decreases in frequency only gradually with time. For the after- shock (fig. 103.3) the main part of the seismic energy is in a higher part of the frequency spectrum, and the envelope of the 10-percent contour decreases more rapidly with time. This difference has been' noted for most seismograms from the Nevada and Montana groups, and we attribute it primarily to differences in the near-surface geology along the propagation path and in the broad Vicinity of the recording stations, rather than to differences in the source mechanism. All other conditions being es- sentially the same, seismograms from recording stations located within predominantly bedrock areas generally are characterized by higher frequency waves and shorter duration of the entire wave train than are seismograms from stations located within predominantly alluviated areas. Conversion and scattering of body and surface waves by changes in geology and topography along the propagation path may account for much of this effect (Tatel and Tuve, 1955). . The data presented here do not permit generali- zations about the character of seismograms of natural and artificial seismic sources. However, they do suggest that the moving-spectrum method furnishes a useful way to study and characterize seismograms. The digital method of preparing moving-spectrum diagrams, as presented here, is more time-consuming than the analog method reported by Ewing and others (1959). However, the digital method has the advantages that seismic data not on magnetic tape can be analyzed; the calculation of phase angles from the Fourier transform program is valuable (for example, Sato, 1960); and quantitative amplitude 3—246 information can be obtained. Recent developments in the preparation of seismic traces for input into digital computers (for example, Adams and Allen, 1961), and of methods for plotting large masses of data, can speed up the digital method of presentation. In the examples presented here, nothing has been brought out by the moving-spectrum presentation, at least in a qualitative sense, that is not already ap- parent by examination of the seismogram itself. Presently, the chief merit of the moving-spectrum method is that it separates the various frequency components in a way that calls attention to events that might be overlooked by the observer, and it provides quantitative information on amplitudes, frequencies, and phase angles that should be helpful in describing and studying the seismogram. It re- mains to be seen if the fine structure and details of these presentations will provide useful information not derived directly from the seismogram. 104. GEOLOGICAL SURVEY RESEARCH 1961 REFERENCES Adams, W. M., and Allen, D. C., 1961, Reading seismograms with digital computers: Seismol. Soc. America Bull., v. 51, no. 1, p. 61—67. Diment, W. H., Stewart, S. W., and Roller, J. C., 1961, Crustal structure from the Nevada Test Site to Kingman, Ari- zona, from seismic and gravity observations: Jour. Geophys. Research, v. 66, no. 1, p. 201—214. Ewing, Maurice, Mueller, Stephan, Landisman, Mark, and Sato, Yasuo, 1959, Transient analysis of earthquake and explosion arrivals: Geofisica Pura e Appl., v. 44, p. 83-— 118. Sato, Yasuo, 1960, Analysis of dispersed surface waves, in Davids, N., ed., International symposium on stress wave propagation in solids: New York, Interscience Publishers, p. 303—327. Stewart, S. W., Hofmann, R. B., and Diment, W. H., 1960, Some aftershocks of the Hebgen Lake, Montana, earth- quake of August 1959, in Short papers in the geological sciences: U.S. Geol. Survey Prof. Paper 400—B, p. B219— B221. Tatel, H. E., and Tuve, M. A., 1955, Seismic exploration of a continental crust, in Poldervaart, Arie, ed., Crust of the earth: Geol. Soc. America Spec. Paper 62, p. 35—50. 6? GRAVITY, VOLCANISM, AND CRUSTAL DEFORMATION IN ANl) NEAR YELLOWSTONE NATIONAL PARK By L. C. PAKISER and HARRY BALDWIN, JR., Denver, Colo. A gravity survey made during 1960 in Yellowstone National Park and adjacent parts of Idaho, Mon— tana, and Wyoming, revealed a pronounced gravity low that coincides approximately with the late Ceno- zoic rhyolites of the Yellowstone Plateau. A narrow north-trending gravity low was also revealed along Madison Valley, west of the Madison Range (fig. 104.1). The area of the Yellowstone Plateau anomaly, inside the zone of steep gradients, is about 1,500 square miles. The steepest gradient, on the southeast side of the anomaly, is 7 milligals (mgals) per mile (fig. 104.1), and the maximum residual gravity relief is about 40 mgals. Gravity was measured at 890 stations, some of them north of the area discussed in this paper. The measurements were reduced to the simple—Bouguer anomaly with respect to the International Ellipsoid (Nettleton, 1940, p. 139—143) using an assumed density above sea level of 2.67 g per cm“, and the resulting data were then contoured at an interval of 10 mgals (fig. 104.1). RELATIONS OF GRAVITY AND GEOLOGY Gravity is high over (a) the pre-Tertiary rocks that form the high mountains north, south, and west of the Yellowstone Plateau, (b) the basalts of the Snake River Plain, and (c) the Tertiary vol- canic breccias east of the Plateau. Gravity is rela- tively low over (a) the Cenozoic rhyolites of the Yellowstone Plateau and (b) the Cenozoic clastic deposits and rhyolites of Madison Valley (fig. 104.1). The gravity low of Madison Valley probably re- flects a narrow graben filled with low-density Ceno- zoic clastic deposits and rhyolites several thousand feet thick, bounded by high-angle faults. A disc-shaped accumulation of rhyolite with gently tapered sides, 10,000 or more feet thick, and 0.3 g per cm“ less dense than the surrounding rocks, could explain a major part of the Yellowstone Plateau gravity low. If the interface of density contrast is deeply buried, the disc-shaped body could have steep or even vertical sides. Using Gauss’s theorem in a manner described by Yokoyama (1958), the mass SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—247 \o ‘3 \ -- 230 Gravity low Lake boundary E X P LA N AT] 0 N Cenozoic elastic deposi xv 1: Cenozoic rhyolite deposi and rhyolite welded tuff + + + Genomic basalt Tertiary volcanic breccias PIE-Tertiary rocks Contact Gravity contour Contour interval 10 milligals 110°00’ 110’00' Geology compiled from State geologic maps of Idaho. Montana. and Wyoming, and from Hamilton (1960) 30 MILES 20 .‘I ‘ u ‘ Iq.:,~ n‘u‘ . 111°00’ 111°00’ ’35 he 2; Ir ’ FIGURE 104.1.—Combined gravity and geologic map of the Yellowstone region, Idaho, Montana, and Wyoming. g‘SNAKE RIVER‘ + + 112°OO' B—248 deficiency corresponding to the gravity low was de- termined to be about 5 X 101“ g, which is equivalent to 4,000 cubic miles of material 0.3 g per cm3 less dense than the surrounding material. If this volume of material is spread over a circular area 40 miles in diameter, the average thickness would be nearly 20,000 feet. . The Yellowstone Plateau gravity data could also be explained in part by (a) a thickening of the low- density silicic upper part of the earth’s crust from, say, 15 to 21 km, (b) a magma chamber, or (c) a silicic batholith. Hamilton (1959, p. 228) has suggested that the rhyolites of the Yellowstone Plateau “ * * * may be the upper crust of a lopolith which has been forming with a complex history since early Pliocene time, an extrusive lopolith roofed by its own differentiates, its mafic bulk hidden beneath its felsic cover * * *”. The mafic bulk of such a lopolith would presumably be dense, especially if it is the mafic fraction of which the silicic differentiate has a mass deficiency as large as 5 X 1018 g. The lack of a positive gravity expression of such a dense mass, assuming that it immediately underlies the rhyolite, must mean that the proposed lopolith does not exist. If the rhyolite differentiated from a mafic magma, it was at such a great depth that the gravity expression of the mafic GEOLOGICAL SURVEY RESEARCH 1961 fraction is overwhelmed by the gravity low of the near—surface low-density rocks of the Yellowstone Plateau. Alternatively, the rhyolites of the Yellow- stone Plateau could have been formed from silicic magma generated by partial fusion of relatively shallow crustal rocks. ' The gravity data are consistent both with F. R. Boyd’s (written communication) conclusion that the Yellowstone Plateau marks the site of a gigantic caldera formed by collapse into a huge underlying magma chamber which may still exist, and with Daly’s (1933, p. 142~143) suggestion that the rhyo— lite may be the foundered crust of a roofless batho- lith of low density, that is, a silicic batholith. REFERENCES Daly, R. A., 1933, Igneous rocks and the depths of the earth: New York, McGraw-Hill Book Co., 508 p. Hamilton, Warren, 1959, Yellowstone Park area, Wyoming: a possible modern lopolith: Geol. Soc. America Bull., V. 70, p. 225—228. Hamilton, Warren, 1960, Late Cenozoic tectonics and vol- canism of the Yellowstone Region, Wyoming, Montana, and Idaho: Billings Geol. Soc. Guidebook 11, p. 92—105. Nettleton, L. L., 1940, Geophysical prospecting for oil: New York, McGraw-Hill Book Co., 444 p. Yokoyama, Izumi, 1958, Gravity survey on Kuttyaro Caldera Lake: Jour. Physics of the Earth, v. 6, p. 75—79. 105. GRAVITY, VOLCANISM, AND CRUSTAL DEFORMATION IN THE SNAKE RIVER PLAIN, IDAHO By D. P. HILL, HARRY L. BALDWIN, JR., and L. C. PAKISER, Denver, Colo. A net of gravity recordings was established over 6,800 square miles of the Snake River Plain in south- western Idaho during 1959 and 1960. The western Snake River Plain is a relatively flat lava plain that trends northwest and ranges in width from 40 to 100 miles. It is bounded on the southwest by the Owyhee Mountains and on the northeast by the mountains of the Idaho batholith. The average elevation of the plain is about 3,000 feet above sea level. The highlands immediately to the north and south of the plainare composed mainly of silicic volcanic rocks of early Pliocene age and of granite of Cre- taceous age. A veneer of basalt flows of middle Pliocene age covers the silicic volcanic rocks in the lower elevations. The western Snake River Plain is a graben filled with Pliocene and Pleistocene sedi- mentary rocks and interbedded basalt flows to a depth of at least 3,000 feet below the surface of the plain (H. E. Malde and H. A. Powers, written communication, 1961). Subsidence of the graben took place along a series of faults trending north- west. The most prominent fault zone forms a sharp escarpment along the northern edge of the Snake River Plain. Malde (1959) estimates that the ag- gregate throw along this zone is at least 9,000 feet. The net of 1,859 gravity stations has an average density of one station per 3.7 square miles. The SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 116° 44°OO’ B—249 O 5 10 15 20 MILES CONTOUR lNTERVAL lO MlLLlGALS 43°30’ \ OWendell l 5 ° \ \/ H '2. g K \J/Iao/V/ \ \/ /°o \ C 7 , 70 < \—/“r Fairfield m. g, ° 7 \ v4, 30 b X -1 7o \\/_\, 6‘ \ \ flee/Av \ \ ‘\ .\j/50, f (3 9o \_ 19° 0 L 01,, \ \\ (\b MOUNTQ‘ilV/H—OME\\\/4 "50 \/ J. 00 \x 0 to a. \ \\~—l;”° —/V 6‘ 63> K \90 77a \ V00 ‘1/0— 0 J 43 ° 00' fl >< KE 0 \ ’5 SNA Glenns oGooding 00 \ Ferry \ \0 1’ \ ’00\ \9 C / /\ \//0 0— ‘7 \ / \/60 42°30‘L nJEROME v2 4 “/30 \ TWIN FALLS FIGURE 105.1.—Simple-Bouguer gravity map of part of the Snake River Plain, Idaho. vertical and horizontal control for the survey was taken from Geological Survey 71/2- and 15-minute topographic maps. The gravity data were reduced to simple-Bouguer values assuming a density of 2.67 grams per em“ down to sea level. These simple- Bouguer values are represented as gravity contours plotted at a 10-milligal contour interval on figure 105.1. , The major anomalies form three elongated, en echelon gravity highs, oriented in a northwest direc- tion. The axes of the gravity highs are parallel to the major fault zones of the region. The central gravity high is the largest of the three; it extends for 95 miles from Wendell north- westward to about 10 miles south of Nampa, has a maximum amplitude of about 70 mgals, and a maxi- mum simple-Bouguer gravity of —66.5 mgals. Gradients are steepest on the northeast side of the anomaly, reaching 6 to 8 mgals per mile in places. The high is divided into two parts in the Vicinity of Glenns Ferry, Idaho. The eastern section of the high is slightly offset to the northeast with respect to the western section. The northern and southern gravity highs are simi- lar in outline and amplitude; both are approximately 35 miles long and have amplitudes of about 20 mgals. The northern. high is offset about 15 miles northeast from the central high, and the southern high is offset about the same distance southwest from the central high. _ , Preliminary two-dimensional analyses, based on an assumed density contrast of 0.3 grams per cm“, have been made along several profiles normal to the axes of the gravity highs. These analyses take into account the fact that the gravity highs are Over the relatively low-density sedimentary deposits of Plio- cene and Pleistocene age. The tops of the anomaly- causing bodies are at least 3,000 feet below the surface as the thickness of these sedimentary de- posits is known. Results of the two-dimensional B—250 analyses suggest that the anomaly-causing bodies extend at least 16,000 feet below sea level and may reach 60,000 feet below sea level, depending on how the shape of the bodies and the regional gravity are assumed. In the preferred interpretation the disturbing masses are approximated by tabular bodies, the largest about 90 miles long, 4 to 6 miles wide, and extending from about 5,000 to 60,000 feet below sea level. A graphical integration using Gauss’s theorem over the surface of the gravity map was used to estimate the total mass excess of the anomalous bodies. A mass excess of about 1 X 10‘” grams, or 1 X 1013 tons, is obtained if the simple-Bouguer back- i ground is taken as ~120 mgals. The volume of this 3 mass excess for material 0.3 grams per cm“ more dense than the surrounding material would be ap- proximately 8,000 cubic miles. Several geological hypotheses have been offered 106. GRAVITY, VOLCANISM, AND CRUSTAL DEFORMATION IN LONG VALLEY, GEOLOGICAL SURVEY RESEARCH 1961 in explanation of the gravity highs. The most im- portant of these are: 1. The Snake River Plain is a broad downwarp that has been filled with extensive basalt flows. 2. The plain is a graben bounded by faults with large vertical displacements. Volcanism has accompanied the subsidence. The resulting lava flows filled the depression, yielding thick accumulations of basalt. 3. Crustal stresses have caused large en echelon fis- sures under the Snake River Plain. These fis- sures have been injected with basalt or basalt- like material. In light of the evidence presented in this paper, the authors believe that the anomalies are explained by a combination of the second and third hypotheses. REFERENCE Malde, H. E., 1959, Fault zone along northern boundary of western Snake River Plain, Idaho: Science, v. 130, no. 3370, p. 272. 6? CALIFORNIA By L. C. PAKISER, Denver, Colo. Work done in cooperation with the California Division of Mines A gravity survey made during 1955 and 1956 in and around Long Valley, Mono County, Calif, led to the discovery of a pronounced elliptical gravity low bounded by steep gradients that coincide ap- proximately with the margin of the basin and with the exposed boundary between Cenozoic volcanic and sedimentary rocks and pre-Tertiary crystalline rocks. The area of the anomaly inside the zone of steep gradients is about 150 square miles, the steep- est gradient on the east end of the anomaly is 20 mgals per mile, and the maximum local gravity re- lief is 78 mgals (fig. 106.1). This is the largest local difference in gravity in the Great Basin reported to date. A prominent gravity high, only suggested at the 10-mgal contour interval of the gravity map (fig. 106.1), was found near the center of the gravity low a short distance west of the intersec- tion of sections A—A’ and B—B’. An aeromagnetic survey of the Long Valley area was flown in 1956. The areal geology shown on figure 106.1 has been generalized from reports by Gilbert (1941), and Rinehart and Ross (1957), and from unpublished work between 1952 and 1959 by C. D. Rinehart, D. C. Ross, and N. K. Huber (C. D. Rinehart, written communication). I am grateful to Mr. Rinehart for permission to use the results of the geologic map- ping in this study. RELATIONS OF GRAVITY AND GEOLOGY Gravity tends to be high over exposures of pre- Tertiary rocks and relatively low over areas where Cenozoic deposits are found at the surface (fig. 118°30' 118°45’ 119°00’ EXPLANATION SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES Cenozoic clastic deposi Cenozoic andesite and basalt Pleistocene Bishop tuff of Gilbert (1938) Cenozoic rhyolite and quartz latite + Pre—Tertiary rocks I: [:1 E Vertical fault based on geophysical evidence ‘2 —/ \—2gg-/ Gravity contour Contour interval 10 milligals a ‘, Vi. an * :‘waivfilx'ohsgr i Jar7< >4 < i I \\§ \ ,, \u“ ~ 5 ‘1‘..“‘§\*\¢:,~ nu: \ ‘“l§ ”‘*\‘¢§‘A‘§ \\\\\‘ *y s II a: ”"(\“*\§\\I I ““ M u" “n/,‘ “n“ \Vll\\\ : I w:\ I u- It Wt sis = §"u” “/ “y 4 s an“! ‘ u” \\ Mir/1* ‘ n: al;.==; ,9. ,‘I*\: '2/ Gravity low A'————1A’ Location of cross section In 2: V m L L m m A 3 8 D c: f) U _ A c ‘3 .—¢ a Q - ‘oU-S 90—1 2P8 "XO LL] 0 E b m E. w H H to :7 (I) 00 ii a _ LO V m N H >2' 0 b O a OH H a IS MEAN SEA LEVEL DATUM FIGURE 106.].~Combined gravity and geologic map of Long Valley, Ca1if., showing locations of profiles A—A’ and 3—H. B—251 B—252 GEOLOGICAL SURVEY RESEARCH 1961 2 "w _ ‘2'< >' 2 r— 20000 "(D (E >_, 2< < 0:5 0 _I <5: ,‘EE Ltd . in: E). 3 ': 0 mm a; as ._ CD r— 150052 m- o: 22 ‘9 A 35 , , 10,000 ‘i J g3 — 3 KILOMETERS -4AJFVVVrL<‘ w, L414>‘7"':44»7* vrmuwlw ; .— ")(j‘q>“( r7 P I .‘iLFv4l>“v>v> 4 A; rl/V) ‘ M r “17; A V‘, A _ _)L A; 4144)(AA‘JL V I <«“vL d) v. <1~4 I "ur J>L .) fa.”- | AV ( 7>Lr(’>r L’i— _ A“; 7‘ >< L E r l > ‘ VrA »\<‘<4 r v<> " 4* L AL» 4 < “r "qn P < FLV<“>LA4VA4L1>4VJVL LVAVVV("“'(»; AA1LJ’VPVrJf V><"vy V444 )V(L.A.—_5 L r4 < 7 4 >A L .v r 7 E ) , L l gr>LL:”_r‘1l7<141Lic444(_1 7‘4)Ln)’1}>44k 7V,F 1000 ................ l 2 1 Bornite .......... 1000 2 Total 200—499 100—199 50—99 1049 <10 Not number (pm) (pm) (pm) (pm) (ppm) foun of samples 97 105 121 132 86 770 1386 2 1 ........ 2 5 3 2 1 l 2 3 7 1 8 2 l i 244 12 8 5 (i 2 8 44 2 1 1 1 ,,,,,,,, (i 1 4 dated Mining Co., who furnished the samples, and Mr. V. E. Lednicky, President, Lepanto Consolidated Mining Co., who kindly gave permission to publish the results. REFERENCES Arsenijevic,‘M., 1959, Germanium in the Bor copper mines: Srpskog geol. Drushtva, Zapisnici for 1957, p. 149—151. Burnham, C. W., 1959, Metallogenetic provinces of the south- western United States and northern Mexico: New Mexico Bur. Mines and Mineral Resources Bull. 65, p. 1—76. E1 Shazly, E. M., Webb, J. S., and Williams, David, 1957, Trace elements in sphalerite, galena, and associated min- erals from the British Isles: Inst. Mining and Metallurgy Trans., v. 66, p. 241—271. Fleischer, Michael, 1955, Minor elements in some sulfide min- erals: Econ. Geology, 50th anniversary Volume, p. 970— 1024. Goldschmidt, V. M., and Peters, 01., 1933, Zur Geochemie des Germaniums: Gesell. Wiss. Gottingen Nachr., Math.- phys. Kl., Heft 2, p. 141—166. Gonzales, Arsenio, 1956, Geology of the Lepanto copper mine, Mankayan, Mountain Province, in Copper Deposits of the Philippines, Part 1, Text: Manila, Philippine Bur. Mines, Spec. Projects Sen, Pub. No. 16, p. 17—50. Haranczyk, Czeslaw, 1957, Trace elements in ore minerals from Silesian Cracovian zinc lead deposits: Inst. geol. (Poland), Buil. 115, p. 63—126 (Polish with English summary). Noddack, Ida, and Noddack, Walter, 1931, Die Geochemie des Rheniums: Zeitschr. physikal. Chemie, v. 154 A, p. 207— 244. Papish, Jacob, Brewer, F. M., and Holt, D. A., 1927, Ger- manium, XXV, Arc spectrographic detection and estima- tion of germanium. Occurrence of germanium in certain tin minerals. Enargite as a possible source of ger- manium: Am. Chem. Soc. Jour., v. 49, p. 3028—3033. 6% 111. CHLORINE AND FLUORINE IN SILICIC VOLCANIC GLASS By HOWARD A. POWERS, Denver, Colo. The chlorine and fluorine content of 120 samples of silicic volcanic glass is plotted on figure 111.11. Five of the samples are matrix glass separated from blocks of vitrophyric pumice, and 115 samples are vitric shards from beds of volcanic ash. The chlorine content differs from ash bed to ash bed independently of the fluorine content, and differences in both chlorine and fluorine content have no apparent re- lation to geologic age. The Galata ash in Montana and Alberta (Horberg and Robie, 1955, p. 949) is postglacial, the Pearlette ash in Kansas (Carey and others, 1952, p. 13) is late Kansan, the Reager and 1Chlorine content was determined by a method described by Peck and Tomasi (1959). Reamsville ash beds in the central Great Plains (Swineford and others, 1955, p. 254), the Peters Gulch and the Narrows ash layers in Idaho (Powers and Malde, Art. 70), the Wray ash in Colorado, and five beds labeled “X” on figure 111.1 are all of Pliocene age from the Snake River Plain, Idaho. The content of Cl and F is fairly constant in different samples from the same ash bed except in those from the Pearlette; 14 samples from the type Pearlette localities range in C1 from 0.12 to 0.15 percent and in F from 0.13 to 0.17 percent. Even greater ranges are found in samples of the glass from three blocks of pumice collected by R. L. Smith and R. A. Bailey from different parts of the Bandelier tufl' from the B-262 GEOLOGICAL SURVEY RESEARCH 1961 I I I I I I 0.15% ,_ z _ LAJ U 5 0.0.10— ; g _ E o 0 3 _ 0 If @ _ 0 ~ A I_ . 0.05 c . . D. A. _ o 0 IA _ o o ‘ . 0 ° A o l— ‘ 0+6i'6 I I i I I I l I I 0.05 0,10 0.15 CHLORINE. IN PERCENT + EXPLANATION Sample known to be from named ash bed 0 Sample sIrnilar physically and chemically to named ash bed Isolated sample known to be different from other known beds Known individual ash beds 1 Galata 5 Peters Gulch 2 Pearlette 6 Narrows 3 Reager 7 Wray 4 Reamsville 8 Sand Point 9 Recent pumice. Saint Helens 0 Sample of unknown relatIon El Pumice from BandalIer rhyolIte tuft (SmIth. 1938) X Unnamed ash bed of PlIocene age FIGURE 111.1.——Chlorine and fluorine content in silicic volcanic glass. Valles caldera in New Mexico (R. L. Smith and R. A. Bailey, oral communication, 1960); these samples contain Cl 0.20 and F 0.14, CI 0.09 and F 0.05, and Cl 0.14 and F 0.04 percent, respectively. In contrast, 2 samples of glass from blocks of Re- cent pumice from St. Helens volcano in the Wash- ington Cascades (D. R. Mullineaux, oral communica- tion, 1961) are very similar in their content, Cl 0.07 and F 0.03 and Cl 0.08 and F 0.03 percent, re- spectively. ‘ More data are available from US. Geological Survey analytical laboratories on fluorine content than on chlorine. The fluorine content of 555 samples (including the 120 mentioned above) of silicic vol- canic glass of late Cenozoic age collected from many places in the western United States is summarized as follows: Percent F: No. of samples: 20 0.01 .02—.06 .07—.08 .09—.12 .13—.17 .19—.30 295 40 105 80 15 The source area from which many of these samples were erupted is knowF, and some 10f the data support the conclusion of R. R. Coats (1956, p. 76) that the abundance of fluorine, and of several other elements present in trace amounts, differs in different igneous provinces. For instance, 75 samples known to be SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 from the High Cascade volcanoes range from 0.005 to 0.065 percent F; 30 samples of early Pliocene age from a province overlapping the Idaho-Nevada border range from 0.065 to 0.14 percent F; and 7 samples of the younger silicic tuffs in the Thomas Range in west-central Utah (M. H. Staatz, written communication, 1960) range from 0.14 to 0.32 per- cent F in contrast to 4 samples of the older series of rhyolite-latite rocks that contain from 0.04 to 0.07 percent F. However, the different content of fluorine in the 3 blocks of pumice from the Bandelier rhyolite tuff does not support the generalization. Friedman and Harris (written communication, 1961) have determined that hydration of volcanic glass does not drive out a measurable part of the fluorine contained in the original glass, but no simi- lar tests have been made in respect to chlorine. 112. B—263 REFERENCES Carey, J. S., Frye, J. C., Plummer, N., and Swineford, Ada, 1952, Kansas volcanic ash resources: Kansas State Geol. Survey Bull. 96, pt. 1, p. 1—68. Coats, R. R., 1956, Uranium and certain other trace elements in felsic volcanic rocks of Cenozoic age in western United States, in Contributions to the geology of uranium and thorium by the United States Geological Survey and Atomic Energy Commission for the United Nations Inter- national Conference on Peaceful uses of atomic energy, Geneva, Switzerland, 1955: U.S. Geol. Survey Prof. Paper 300, p. 75—78. Horberg, Leland, and Robie, R. A., 1955, Postglacial volcanic ash in the Rocky Mountain Piedmont, Montana and Alberta: Geol. Soc. America Bull., v. 60, p. 949—956. Peck, L. C., and Tomasi, E. J., 1959, Determination of chlorine in silicate rocks: Anal. Chemistry, v. 31, p. 2024—2026. Swineford, Ada, Frye, J. C., and Leonard, A. B., 1955, Petrography of the late Tertiary volcanic ash falls in the central Great Plains: Jour. Sed. Petrology, v. 25, p. 243—261. 5% ELECTRONPROBE ANALYSIS OF SCHREIBERSITE (RHABDITE) IN THE CANYON DIABLO METEORITE By I. ADLER and E. J. DWORNIK, Washington, D. C. Work done in cooperation with the National Aeronautics and Space Agency The problem of the mode of formation of metallic meteorites requires thorough and detailed knowledge of their composition. The many existing analyses made by conventional methods are essentially analyses of composites; many problems, however, such as the distribution of nickel and cobalt between two different phases in contact, require analyses of specific localized areas definable only under high magnification. For example, analyses exist of kama- cite (alpha-Ni-Fe), taenite (gamma-Ni-Fe), schrei- bersite (Fe,Ni)3P and cohenite (Fe,Ni).-;C from meteorites, but nearly all of them represent com- posite samples. It is of great interest to analyze individual grains to determine the constancy or variation in composition of each phase, and the con- stancy or variation of ratios of elements (such as N izFe) in two adjacent phases. Such studies could yield valuable information on whether equilibrium conditions prevailed. The electronprobe is ideally suited to this type of analysis as it can be used to provide point by point analysis of microscopic volumes of the order of several cubic microns which in the ideal case correspond to absolute amounts of 10—n to 10’” grams of an element. The electronprobe microanalyzer was developed in France by Castaing (1951, Application of electron probes to local chemical and crystallographic analy- sis, Paris Univ. Thesis). This device has been de- scribed in a number of reports dealing in the main with metallurgical applications. A particularly appealing feature is the nondestruc- tive nature of the technique which enables the re- searcher to reexamine the specimen in the light of the compositional data obtained. The tedious prep- aration of any constituent phase for analysis by con- ventional methods can be circumvented. : B—264 GEOLOGICAL SURVEY RESEARCH 1961 Maringer, Richard, and Austin (1959) have stud- ied the Widmanstatten structure in the Grant meteo- rite from New Mexico with an electronprobe and reported on the nickel-iron content of kamacite, tae- nite, and plessite—a fine-grained mixture of both phases. David B. Wittry (written communication, 1959), using the electronprobe, reported on the nickel-iron content of kamacite and taenite in the Canyon Diablo meteorite. He also described an in- dividual crystal within a taenite band and tentatively identified it as N i3Fe2Pg. Presumably, this is similar to the rhabdite rhombs of this study. . , g , ‘ A one-quarter by one-eighth inch fragment was - . _I , ‘ carefully removed from the edge of the Canyon 1 . _ Diablo meteorite specimen 841, generously provided FIGURE 112.1.—Photomicrograph of polished specimen of Canyon Diablo meteorite. Rhabdite grains, E, D, F, and G. Briefly, in principle, a focused beam of electrons is made to impinge on a selected area of the specimen. The X-rays which are excited are diffracted by analyzers, which are various single crystals with characteristic interplanar spacings to cover the range of elements of atomic number 12 and greater. The intensity of the X-radiation is measured by radia- tion detectors such as Geiger or proportional count- ers and scalers. The intensities measured are com- pared with those given by standards, and corrections are made for fluorescence and absorption in order to relate the intensities to concentration. A probe simi- lar in principle to the Castaing probe, but somewhat modified in design, is now in operation in the U-S-l FIGURE 112.2.—View enlarged from figure 112.1 to show point- Geological Survey laboratories. by-point traverses I and II. TABLE 1.-—Analytical results for traverses I and II [In percent; precision of measurements approximately 5 percent of the amount present] Traverse I Traverse 11 Spot Ni Fe Ni+ Fe Spot Ni Fe Ni+ Fe Kamacite. ...... 1 7.8 88 96 Kamacite ...... 1 6.5 89 96 2 7 . 9 88 96 2 6 . (i 90 97 3 7.9 91 l 99 _ 4 7.4 86 93 Gray phase. . . . 5 1 .4 48 49 Gray phase. . . . 3 3. l 46 49 (i 2.0 46 48 ' Rhabdite ...... 7 38 40 78 Rhabdite ...... 4 42 43 85 Gray phase. . . . 8 2.5 41 44 Gray phase. . . . 5 3.9. 40 44 9 1.4 46 47 _ 10 2.4 47 49 Kamac1te ...... 11 7 .4 90 97 Kamacite. . . . . . 6 7.2 90 97 12 7.6 89 97 7 7.2 89 96 13 7.2 89 96 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1—146 TABLE 2.—New analyses of rhabdites, Canyon Diablo meteorite [In percent; precision of measurements approximately i 5 percent of the amount present] Size Nich Grain . (microns) Ni Fe NH— Fe (ratios) 10 22 63 85 34 31 41 46 87 89 2] 37 42 79 88 5 48 36 81 l 33 20 ~15 39 84 1 I5 18 44 39 83 l .12 35 H 38 82 1.15 by E. P. Henderson of the U.S. National Museum, and the fragment was prepared for examination in the conventional bakelite polished-section mount. Fragments of pure iron, pure nickel, and stainless steel (National Bureau of Standards standard sam- ple no. 101d) were also mounted for use as reference standards. Figure 112.1 illustrates the general area studied. The various phases present, as described in metallographic studies of meteoritic irons by Perry (1944), include a kamacite matrix, irregularly shaped gray bodies (probably iron oxides with some carbon in the form of graphite), and schreibersite, an iron-nickel phosphide, (Fe,Ni),~,P, as rhombs or squares and referred to as rhabdites. The gourd-shaped gray mass in the upper right of figure 112.1 is the site of two separate point by point traverses for which analytical data are given in table 1. The small regularly spaced spots on a line through the area are contamination spots formed by the electron beam. The spots are normally of the order of 1 to 3 microns but appear somewhat en- larged because of prolonged exposure to the beam. In figure 112.2 these spots are numbered so that the analyses can be related to the particular area. Also shown in figure 112.1 are 4 of the 7 additional rhab- dites for which Ni-Fe contents were determined (table 2). Appreciable amounts of phosphorus in these rhabdite grains were demonstrated by spec- trometer traces but the element was not determined quantitatively. The theoretical content of phosphor- ous for (Fe,Ni)3P with Fe:Ni = 1:1 is 15.27 per- cent. The magnetism of the meteorite made it necessary to recenter the beam with respect to the optical mi- croscope in moving from point to point and accounts for the unnumbered beam spots appearing in the micrographs. The rhabdite grain D (figs. 112.1 and 112.2), approximately 5 microns across and the B—265 smallest of the 9 crystals analyzed, has been con- cealed by the contamination spot. No clear-cut chemical relationship between the rhabdites and the surrounding gray areas could be established. The total Ni —+— Fe in rhabdite grain F, exhibiting virtually no oxide halo, corresponds closely to the total in other rhabdites. Grains A and D, which show the maximum variation in Ni and Fe content, both show good agreement with the for- mula (Ni,Fe);,P used by Perry (1944) for schrei- bersite. Henderson and Monnig (1956), analyzed rhabdite needles removed from the Richland, Tex., and Coahuila, Mex., meteorites by dissolving the kamacite matrix in dilute hydrochloric acid. They report 33.17 and 31.71 percent Ni, respectively. The average nickel content of the 9 rhabdites analyzed in this study is 40.1 percent. The present study clearly demonstrates the va- riation in content of iron and nickel in rhabdites in‘ one single meteorite specimen. The nickel in these rhabdites ranges from 22 percent in grain A to 48 percent in grain D; the NizFe ratios range from 0.34 to 1.33. The sum of the weight percents of nickel and iron range from 79 to 87 percent. Two analyses of schreibersite from the Canyon Diablo meteorite are given by Palache, Berman, and Fron- del (1944, p. 125) as follows: Fe 58.54, Ni 26.08, and Ni :Fe 0.44 percent; and Fe 54.34, Ni 31.48, and Ni :Fe 0.57 percent. Eleven analyses of the kamacite phase adjacent to the gourd-shaped area show average contents of 7.3 percent nickel and 89 percent iron; the range in composition is strikingly less than in the rhabdites, namely, Ni 6.5 to 7.9 and Fe 86 to 91 percent. The gray phase has the lowest nickel content, 1.4 to 3.1 percent; its iron content is 46 to 48 percent. REFERENCES Henderson, E. P., and Monnig, O. E., 1956, The Richland, Navarro County, Texas, meteorite (CN:0964,319)-—A new hexahedrite: Meteoritics, v. 1, no. 4, p. 459—467. Maringer, R. E., Richard, N. A., and Austin, A. E., 1959, Microbeam analysis of Widmanstatten structure in me- teoritic iron: Am. Inst. Mining Metall. Engineers, Metall. Soc. Trans, v. 215, p. 56—68. Palache, Charles, Berman, Harry, and Frondel, Clifford, 1944, The system of mineralogy of James Dwight Dana and Edward Salisbury Dana, Volume 1, Elements, sulfides, sulfosalts, oxides. 7th ed.: New York, John Wiley and Sons, 834 p. Perry, S. H., 1944, The metallography of meteoric iron: U.S. Natl. Mus. Bull. 184, 206 p. 6% B—266 113. GEOLOGICAL SURVEY RESEARCH 1961 THE SYNTHESIS OF LARGE CRYSTALS OF ANDERSONITE By ROBERT MEYROWITZ and DAPHNE R. Ross, Washington, D. C. Andersonite, NagCaUOg(C03)g-6H20, was first synthesized by Axelrod and others (1951) from a solution containing uranyl nitrate, potassium carbo- nate, sodium nitrate, and calcium nitrate. Micro- scopic crystals were formed by allowing the solution to evaporate at room temperature. The procedure described below was developed to prepare large crystals (0.5 to 1 mm and occasionally some slightly larger) of synthetic andersonite. An aqueous solution (10 ml) containing 7.53 g U02(N03)2-6H20 (0.015 mol U03) is added slowly with constant stirring (magnetic stirrer) to an aqueous solution (100 ml) containing 4.77 g an— hydrous Na2C03 (0.045 mol C02). An aqueous solu- tion (10 ml) containing 3.54 g Ca(N03)2-4H20 (0.015 mol CaO) is added slowly with constant stirring to the uranyl carbonate solution. Dilute 114. sodium carbonate is added dropwise with constant stirring until the pH of the solution is 8.0. The solu— tion is allowed to stand after sealing the beaker with plastic film so that no evaporation takes place. The crystals which form on standing are detached from the sides and bottom of the beaker and washed by decantation with water. Most of the excess water is removed by rolling the crystals on absorbent paper. The crystals are then allowed to air dry. They were identified as andersonite by their powder X-ray dif- fraction patterns (Axelrod and others, 1951). The help of Alan L. Meyrowitz is acknowledged. REFERENCE Axelrod, J. M., Grimaldi, F. 8., Milton, 0., and Murata, K. J., 1951, The uranium minerals from the Hillside Mine, Yavapai County, Arizona: Am. Mineralogist, v. 36, p. 1—22. 6? UNIT-CELL DIMENSION VERSUS COMPOSITION IN THE SYSTEMS: PbS-CdS, PbS-PSe, ZnS-ZnSe, and CuFeSI,m-CuFeSe..im By PHILIP M. BETHKE and PAUL B. BARTON, JR., Washington, D. C. As part of an extensive experimental investigation of the distribution of minor elements between co- existing Sulfide minerals (Bethke and Barton, 1959), the relationship between unit-cell edge and composi- tion was established with high precision for PbS- PbSe and ZnS-ZnSe solid solutions and cadmium- bearing galenas. The relationship between a and com- position for CuFeSLW—CuFeSLm, solid solution was also established, but with less precision. Shirley K. Mosburg made and measured a num- ber of the X-ray diffraction runs. Jean Bethke meas— ured and computed all the PbS—PbSe diffraction patterns. SAMPLE PREPARATION Pure PbS, PbSe, ZnS, ZnSe, and CdS were pre— pared from high-purity elements. The metals were heated for several days at about 750°C in evacuated silica glass tubes with a slight excess of sulfur (or selenium) over the stoichiometric proportions. Ex- cess sulfur or selenium was removed by repeated washing with warm carbon disulfide in a soxhlet extractor. Solid solutions of various compositions were pre- pared by sintering mechanical mixtures of the above end members in evacuated silica glass tubes until a single homogeneous phase was formed. CuFeSLW— CuFeSeHm solid solutions were prepared directly from mixtures of the elements. The iron, zinc, and sulfur are the same reagents used by Skinner, Barton, and Kullerud (1959). The sources and analyses of the selenium, cadmium and lead used in this study are given in table 1. Reagents were weighed to i 0.05 mg and the total weight of the charges ranged between 100 and 500 mg. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 X-RAY DIFFRACTION TECHNIQUES All X-ray diffraction data were gathered on a Norelco diffractometer using copper radiation (A : 1.54050A). The ZnS—ZnSe and PbS—CdS sys- tems were analyzed at our laboratory in Washington using the counting rate computer. The bulk of the PbS—PbSe data were gathered at the Missouri School of Mines and Metallurgy at Rolla, M0., using an oscillating technique. The chalcopyrite data were gathered in Washington, also by the oscillating tech- nique. In all cases the peaks of the samples were measured against those of various internal standards that had been mutually calibrated against silicon powder supplied by Dr. Gunnar Kullerud of the Geo- physical Laboratory, Carnegie Institution of Wash- ington. The cell edge of a = 5.4301A for silicon, given by Swanson and Fuyat (1953), was used. Pre- cision of measurement by either method was i: 0.005° 26, and various checks indicate that data gathered by either method, in Washington or Rolla, are mutually comparable, within the limit of pre- cision of measurement. Diffraction slides were prepared by evaporating a slurry of the sample and internal standard in amyl acetate onto a microscope slide. Oscillation tracings were made at a scanning rate of 14° 20 per minute with a chart speed of half an inch per minute. The step scan interval was 001" 20. Two sets of measure- TABLE 1.—Spectrographic analyses of reagents (in weight percent) lN.D., looked for but not detected; . . . not specifically looked for; V.F. Tr., very faint trace] Element Lead 1 Cadmium 2 Selenium 2 Ag. 0.001 0.0001 NJ). Al .......... N.D. ................ NJ). As .......... N.D. N.D. 0.0001 Bi .......... 0.0003 0.001 NJ). Ca. N.D. N.D. NJ). Cd. N.D. (3) NJ). Cr .......... N.D. N.D. NJ). Cu. 0.003 0.001 V.F. Tr Fe .......... 0.001 0001 NJ). Hg .......... N.D. N.D. N.D. In .......... N.D. 0.001 NJ). Mg ......... 0 . 00003 0.00001 N.D. Mn ......... N.D. N.D. NJ). Na. .. N.D. ................ NJ). Ni .......... 0.001 N.D. N.D. Pb .......... (3) 0.003 N.D. S1) .......... NJ). N.D. N.D. Si .......... N.D. N.D. NJ). Se .......................................... (3) Sn .......... N.D. 0.0001 N.D. Te.. N.D. N I). 0.0001 V. .. 0.0001 .............................. Zn.. N.D. N.D. \.D. 1 National Bureau of Standards melting point standard 49d. Semi-quanti- tative spectrograph analysis by K. V. Hazel, U.S. Geological Survey. 2 Spectrographic analysis by supplier: American Smelting and Refining Co. 3 Major constituent. B—267 ments were made for each sample, the slide being rotated 180° in its own plane between each set. At least three complete oscillations were made in each set when using the oscillation technique. Measure- ments were made at 25 : 2°C. The values of the cell edges given are numerical averages of all meas- urements on a given sample. The plus or minus at- tached to the cell edges is the standard deviation computed from the deviations from the average values for all the samples in a given system, regard- less of composition. BecaUse galena deforms on grinding, giving rise to diffuse X-ray reflections, the galena crystals were reduced in size by giving them several sharp “raps” with a pestle. The sample was then sized and only those fragments smaller than 200 mesh used to prepare the slide. The galena reflections were very sharp, even at high angles, using this procedure. CELL EDGES OF PbS, ZnS, PbSe, AND 21188 The cell edges of pure PbS, PbSe, ZnS, and ZnSe were determined from a large number of individual measurements, all from oscillation tracings. These values, together with the peaks measured, internal standards used, and number of measurements made are given in table 2. The plus-minus attached to each value is the standard deviation computed from all the measurements. The value of a for ZnS determined in this study is in exact agreement with that reported by Skinner and Barton (1960) and Skinner, Barton, and Kul- lerud (1959). Our value of 5.9358 : 0.0002 A for PbS is in excellent agreement with that of Wasser- stein (1951) (5.9360 : 0.0004 A‘) and of Swanson and Fuyat (1953) (5.9362). Our value of 6.1255 : 0.0004 A for the cell edge of PbSe is in only fair agreement with that of 6.1243 A reported by Swan- son and others (1955), but is much more consistent with our data on PbS—PbSe solid solutions. Our value of 5.6685 1- 0.0004 A for ZnSe is in good agreement with the less precise value of 5.667 A TABLE 2.—Cell edges of PbS, PbSe, ZnS, and ZnSe L 1 Number of (‘0m- Average a in A Standards Reflections measured . measure- pound 5 1 used 1 ments _E,-,, _ii__ih SAWS).:_,-.c,,-_-_iz,-sagafi‘ PbS 5 . 9358 i 0 . 0002, Can ‘(600) (620) (5315) (444) 141 PbSe 6. 1255 i0.0004 CaFg 1 (620) (640)(Tl 1) 128 and PbS , ZnS 5 . 1093 i0 . 0002 (7an l (620) 30 ZnSe 5. 0685 i0 . 000-1 Can l (620) 33 l 1 Converted from kX units by the kX/A conversion factor of 1.00202. B-268 5.920 5.880 a IN ANGSTROM UNITS 5.860 Cubic cleavage MOL PERCENT CdS IN GALENA FIGURE 114.1.—a versus composition for cadmium-bearing galenas. Size of circle equals 2 times standard deviation of individual a determinations. reported by Swanson and others (1954). Again our value is entirely consistent with our data on ZnS— ZnSe solid solutions. PbS-CdS SOLID SOLUTIONS A series of solid solutions in the system PbS—CdS was prepared from the pure end members by holding carefully weighed mixtures of the end members at 860°C for a period of two weeks. The limit of solid solution at this temperature is approximately 17.5 mol percent CdS. The cell edges determined for these compositions are given in table 3. The relationship 1 l 1 .\101 percent (‘dS 1 a measured : (1 (1002.4 1 a calculated 1 Difi‘crence 1 l ‘ 1 1-57,, "”1 ’““““ i “‘ “ ‘ l 0 ......... 1 59358 59359 1 40.0001 ’1 .28 ......... 1 59347 1 5.9347 1 .0000 1 .40 ......... 1 59340 1 59342 1 — .0002 1 .04 .......... 59330 1 59332 + .0004 .80 ......... 1 59327 5.9325 1 + .0002 1 .98 ........ 59317 1 59318 — .0001 1 1.07 ......... 1 59289 5.9289 1 0000 1 2.77. ....... 1 5.9244 1 59243 1 + .0001 1 7.00 ......... 1 59003 59003 1 .0000 1 9.98 ......... 5.8942 5.8941 1 + .0001 1 10.27 ..... 1 58070 59077 1 — .0001 1 1 7 GEOLOGICAL SURVEY RESEARCH 1961 TABLE 4.—Cell edges of ZnS-ZnSe solid solutions fracture and composition. 3 galenas retain a cubic cleavage and break along this a conchoidal fracture is seen. Linear cell. edge Linear cell volume assumption assumption .\lol percent a 111easurcd ZnSe t0.00(14A a calculated Difference a calculated Dillcrence 0 ...... 5 , 4093 ....................................... 7.72. . 5.4290 5.4293 —0.0003 5.4302 —0.0012 14.30. . 5.4458 5.4464 — .0006 5.4479 — 0021 30.04. . 5.4865 5.4872 — .0007 5.4898 — 0033 33.35 5.4939 5.4957 —~ .0018 5.4985 — 0046 49.84 5.5375 5.5385 — .0010 15.5415 — 0040 69.22 5.5870 5.5887 — .0017 15.5415 — 0044 77.11 5.6096 5.6092 +0004 15.6113 — 0017 100.00 5.6685 ..................... ‘ ................ of cell edge to composition is illustrated in figure 114.1. The best fitting straight line determined by least squares analysis of the solid solution data intersects the 0 axis at a value of a = 5.9359 A, almost exactly that determined for pure PbS. The equation of this line is a = 5.9359 -— 0.004194 mol percent CdS where a is in A units. The standard deviation of the measured values of a of PbS—CdS solid solutions from those calculated through the above relationship is less than 1— 0.0002 A. The extrapolated value of a for a hypothetical pure CdS having the galena structure is 5.516 A. An interesting feature of the PbS—CdS solid solu- tions is the relationship between cleavage and (or) Low cadmium-bearing cleavage almost exclusively. At compositions above about 6 mol percent CdS, however, a conchoidal frac- ture appears in addition to the cubic cleavage. With increasing CdS content the number of cleavage sur- faces seen in a crushed sample decreases, until for CdS concentrations over 15 mol percent only the These comments are TABLE 5.—Cell edges of PbS-PbSe solid solutions l l 1 Linear cell edge Linear cell volume assumption assumption 3101 i, 7 ,1 .1. percent a measured Pbb'c 1 itHlOlHA 1 a calculated 1 Difference ,, calculated Difi'erence A 1 1 5.1 _i 0....-..1 5.93581 ......... 1 .............................. 10 . 00. . 1 5 . 9547 5.9549 1 —0.0002 5 . 9554 —0 0007 20.70.. 5.9758 5.9751 1 +0007 5.976] — 0003 30. 15. . 1 5 . 99—11 5 . 9930 + .0011 5.9943 .— 0002 39.83.. 6.0126 6.0114 +0012 6.0128 —.0002 60.10.. 1 6.0507 6.0498 + .0009 6.0512 — .0005 79.08.. 6.0871 1 6 .0858 + .0013 6.0868 +0003 90. 72 1 6.1079 1 6.1079 .0000 6.1084 — .0005 100.00.. 1 6.12551 ......... 1 ............................ 1 l SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 based on observation of the spacing curve runs as well as others prepared for other purposes. ZnS-ZnSe AND PbS-PbSe SOLID SOLUTIONS Complete series of ZnS—ZnSe and PbS—PbSe solid solutions were prepared from mixtures of the end members at 900°C and 750°C, respectively. The ZnS—ZnSe runs equilibrated in one month, the PbS— PbSe in two weeks. The cell edge data for these series are given in tables 4 and 5. The ZnS—ZnSe data fall slightly below a straight line drawn between the values of a for the pure end members. Least squares analysis of the solid solu- tion data yields a linear relation between cell edge and composition essentially parallel to the line drawn between the pure end members. This least squares line extrapolates to values of azus = 5.4086 A and ax“. = 5.6679 A. Because of the larger number of measurements used in calculating the cell edges of the end members and because of the minimum com- positional uncertainty, a linear relationship between cell edge and composition passing through the a values of pure ZnS and ZnSe is preferred. The equation of such a line is— a = 5.4093 + 0.002592 mol percent ZnSe where a is in Angstrom units. The small deviation of the solid solution data from this relationship is not considered significant. In contrast, the cell edges of PbS—PbSe solid solutions are not linear functions of composition. Rather, they indicate a linear relationship between cell volume and composition. The differences be- tween measured values of a and those calculated as— 5.390 5.370 5.350 5,330 (1 IN ANGSTROM UNITS 5.3io l l 1 l l l l 10 20 30 MOL PERCENT CuFeSe m FIGURE 114.2.—a versus composition for CuFeSm—CuFeSeLm solid solutions. Size of circle equals standard deviation of individual a determinations. B—269 TABLE 6.—a of CuFeS,.W—CuFeSei.m, solid solutions Mol percent (‘uMeSeLQn i "+0.0015A (‘alculated Difference | 0 .............. ' 5 , 2987 5. 2988 —- 0.0001 5.20 ........... 5.3130 ‘ 5.3128 +.0002 10,53 ........... 5 . 3265 l 5.3269 — .0004 25 . 32 ........... 5 . 3672 5 . 366-1 + .0008 36.84 ........... i 5 . 3965 1 5 . 3971 — .0005 suming both linear cell edge and linear cell volume relationships are given in tables 4 and 5 for both ZnS—ZnSe and PbS—PbSe data. It is immediately obvious from these differences that a linear volume assumption much better describes our data for PbS—PbSe solid solutions, whereas a linear cell edge assumption much better describes our data for ZnS—ZnSe solid solutions. The relationship adopted between cell edge and composition for the PbS—PbSe solid solution is— a = 3V209.140 + 0.20699 mol percent PbSe, where a is the cell edge in Angstrom units. Earley (1950) found an apparently linear relation- ship between cell edge and composition for the PbS— PbSe series. Earley’s study was of broad scale and neither his cell edge measurements nor compositional control were of sufficient precision to differentiate between a linear cell volume or linear cell edge re- lationship with composition. Coleman (1959) has determined the cell edges of 20 analyzed galena-clausthalite solid solutions, mostly from the Colorado Plateau. His objective was to establish the existence of such a series in nature, and his data seem to confirm such a conclu- sion. However, the wide scatter of his data allow only the most general conclusions as to the way in which cell dimension varies with composition. Bloss (1952) and Zen (1956) have emphasized that for ideal solid solutions partial molar volumes are additive. Thus, a linear relationship between cell volume and composition would be predicted, were the solid solutions ideal. Our work on the distri- bution of selenium between sphalerite and galena (Bethke and Barton, 1959) strongly indicates that at least above 740°C both ZnS—ZnSe and PbS— PbSe solid solutions behave ideally. The cell edge measurements reported in this study were made at approximately 25°C, however, and it is possible that the PbS—PbSe solid solutions are ideal, or nearly so, at this temperature, whereas ZnS—ZnSe solid solutions are not. B—270 A great deal of precision of measurement was necessary to establish the additivity of cell volumes for PbS—PbSe solid solutions as opposed to the ad- ditivity of cell edges (Vegard’s LaW) for ZnS-ZnSe compounds, even though the difference in molar vol- umes of the end members is very large. Most meas- urements made on solid solutions are not this pre- cise and few complete solid solution series exhibit such a large volume difference. Further, most natu- rally occurring solid solutions contain other ele- ments as structural impurities in sufficient concen- trations to mask the detailed relations between cell edge and concentrations of the major components. Finally, almost all precise lattice parameter measure- ments are made at room temperature where it is quite likely that solid solutions, although possibly ideal under the conditions of their formation, may show a measurable departure from ideality. For most systems the difference between Vegard’s Law (additive cell edge) and ideal behavior (additive cell volume) is too small to be detectable by standard procedures. CuFeSmo — CuFeSeLm SOLID SOLUTIONS Solid solutions up to 36.8 mol percent CuFeSem0 were prepared in 2 weeks at 600°C starting directly from the elements. Runs with higher selenium con- tent produced spurious phases. The poor quality of the X-ray diffraction patterns of chalcopyrite at high angles, particularly with copper radiation, necessi- tated the use of low-angle lines in establishing the relationship between cell edge and composition for selenium-bearing chalcopyrites. Correspondingly, the precision of measurement was much lower, in terms of cell edge, than for the above-described sys- tems. Although the chalcopyrites measured were tetragonal, only the a dimension, as computed from the (220) reflection is reported here. It should be noted that the chalcopyrite solid solutions were specifically prepared to be anion deficient and with a 1 :1 Cu :Fe ratio in order that they would be within their compositional stability ranges under the condi- GEOLOGICAL SURVEY RESEARCH 1961 tions of the distribution experiments. The results of our study are, therefore, not directly comparable to those obtained on chalcopyrites of different cation: anion or Cu:Fe ratios. The cell edge and compositional data are listed in table 6 and illustrated in figure 114.2. Within the limits of precision, the a dimension of chalcopyrite is seen to be a linear function of selenium content. The data are not sufficiently precise to define the details of the relationship, but it is approximately given by the expression—- a = 5.298,. + 0.00266. mol percent CuFeSeU... where a is in Angstrom units. REFERENCES Bethke, P. M., and Barton, P. B., Jr., 1959, Trace-element distribution as an indicator of pressure and temperature of ore deposition [abs]: Geol. Soc. America Bull., v. 70, no. 12, pt. 2, p. 1569. Bloss, F. D., 1952, Relationships between density and com- position in mol percent for some solid solution series: Am. Mineralogist, v. 37, p. 966—981. Coleman, R. G., 1959, The natural occurrence of galena- clausthalite solid solution series: Am. Mineralogist, v. 44, p. 166—175. Earley, J. W., 1950, Description and synthesis of the selenide minerals: Am. Mineralogist, v. 35, p. 337—364. Skinner, B. J., and Barton, P. B., Jr., 1960, The substitution of oxygen for sulfur in wurtzite and sphalerite: Am. Mineralogist, v. 45, p. 612—625. Skinner, B. J., Barton, P. B., Jr., and Kullerud, Gunnar, 1959, Effect of FeS on the unit-cell edge of sphalerite. A re- vision: Econ. Geology, v. 54, p. 1040—1046. Swanson, H. E., and Fuyat, R. K., 1953, Standard X-ray diffraction powder patterns: U.S. Natl. Bur. Standards Circ. 539, v. 2, p. 6—9, 18—19. Swanson, H. E., Fuyat, R. K., and Ugrinic, G. M., 1954, Standard X-ray diffraction powder patterns: U.S. Natl. Bur. Standards Circ. 539, v. 3, p. 23. Swanson, H. E., Gilfrich, N. T., and Ugrinic, G. M., 1955, Standard X-ray diffraction powder patterns: U.S. Natl. Bur. Standards Circ. 539, v. 5, p. 38—39. Wasserstein, /B., 1951, Precision lattice measurements of galena/Am. Mineralogist, v. 36, p. 102—115. Zen, E-an, 1956, Validity of “Vegard’s Law”: Am. Miner- alogist v. 41, p. 523-524. 5? SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 115. B—271 UNIT-CELL EDGES 0F COBALT- AND COBALT-IRON-BEARING SPHALERITES By WAYNE E. HALL, Washington, D. C. Pure ZnS, "‘COS”, and FeS were prepared by combining high-purity elements in sealed, evacuated silica glass tubes. The iron, zinc, and sulfur are the same reagents used by Skinner, Barton, and Kul- lerud (1959). The cobalt reagent was obtained from Johnson, Matthey and Co., Ltd., catalogue no. J. M. 870, Who supplied the following spectrographic analysis: Percent Percent Ag <0.0001 Mg <0.0001 Al ________ Mn ,,,,,, As ,,,,,,,, Mo Ba Na .0001 Bi _ . . Ni Ca .0002 Pb ________ Co Major Sb Cr ________ Si .0002 Cu < .0001 Sn ,,,,,,, Fe .0005 V ________ Ge ....... Zn _______ ZnS was prepared by heating zinc with sulfur in slight excess of stoichiometric proportions for 10 days at 650°C. Excess sulfur was removed by wash- ing with carbon disulfide. FeS and “COS” were pre- pared by combining stoichiometric mixtures at 650°C for at least 7 days. Stoichiometric COS was not formed, but the resulting intergrowth of COHS and probably C098,. was so fine and uniform that it had the bulk composition COS in the quantities used for individual runs. Definite identification of the two phases has not been completed, and the inter- growth will be referred to hereafter as “COS”. All X-ray data were obtained using Ni-filtered CuKa] radiation (A = 1.54050A). An oscillation tech-‘ nique was used, and all peaks were repeated at least 4 times at a scanning speed of 1/4° 20 per minute and a chart speed of half an inch per minute. The peaks were measured against those of the same CaFg or NaCl internal standards used by Bethke and Bar- ton (Art. 114). Several checks were made by using a counting-rate computer at a step-scanning rate of 001° 20, and the unit-cell edge measurements by both techniques are comparable. Shirley K. Mosburg made most of the X-ray difiraction patterns and cal- culated the unit-cell edges. The unit-cell edge of ZnS determined as 5.4093A in this investigation is the same as that determined by Skinner and others (1959, p. 1043), Skinner and Barton (1960), and Bethke and Barton (Art. 114). COBALT-BEARING SPHALERITE A series of cobalt-bearing sphalerites was pre- pared from “COS” and pure ZnS by holding known proportions of the two at 850°C for 21 days. At the end of one week the silica glass tubes were opened and the samples reground in acetone. The charge was then reheated at 850°C until homogeneous. The cell edges of the cobalt-bearing sphalerites are listed in table 1, and the relation of cell edge to composition is shown in figure 115.1. The relation is linear, and the best fitting straight line by least squares analysis intersects the (1 axis for pure ZnS at 5.4093A. The equation for the line is: a. = 5.4093 — 0.00700Y where Y is the mo] percent “COS”. The maximum amount of COS that can substitute in ZnS is 33 mol percent at 850°C. The precision given for each unit-cell edge measurement is the maximum deviation from the numerical average of 4 to 6 re- peated measurements. A comparison of the measured and calculated unit-cell edges based on a linear re- lationship between a and composition is also given in table 1. The standard deviation of the measured values of a and those calculated by the above for- mula is 0.0003A. COBALT-IRON-BEARING SPHALERITES A series of cobalt-iron-bearing sphalerites were prepared from known proportions of pure ZnS, FeS, and “COS”, and were heated at 850°C for 4 weeks. 5.410 — I l l l I I I 5.405 1' 8 a , IN ANGSTROM UNITS U! in . to U! . “3* l l l l I 53850 5 1o 15 20 25 sh 315 MOL PERCENT COS FIGURE 115.1.—Relation of a and composition in cobalt-bearing sphalerites. B—27 2 TABLE 1.—Um't cell edges of cobalt-bearing sphalerite COS content ________________ Unit—c611 Unit-(tell Weight Mol edge in A edge in Difference percent percent (measured) (calculated) 0.57.... 0.60 5.4090i0.0003 5.4089 -0.0001 2.21.... 2.36 5.4078i .0002 5.4076 —.0002 3.70.... 3.95 5.4068i .0003 5.4065 —.0003 5.90.. 6.28 5.4045 i .0003 5.4049 + .0004 7.23. . . . 7.70 5.4042 i .0004 5.4039 — .0003 9.75.... 10.36 5.4025 i .0005 5.4020 — .0005 14.34.... 15.19 . 5.3990i .0002 5.3987 — .0003 19.94.... 21.05 5.3948i .0002 5.3946 —.0002 23 32. . 24.56 5.3918i .0003 5.3921 + .0003 The charges were reground in acetone after 2 weeks. The measured unit-cell edges are listed in table 2. These are compared with a calculated unit-cell edge based on a linear relation between a of cobalt-bearing sphalerite and a of iron-bearing sphalerite. The ef- fect of FeS on the unit-cell edge of sphalerite was in- vestigated by Kullerud (1953) and by Skinner and others (1959). The latter derived the linear function: a = 5.4093 + 0.000456X (Where X is the mol percent FeS and a is in Angstrom units). This equation was combined with the one deter- mined in this investigation for cobalt-bearing sphal- erite to give the a for cobalt-iron-bearing sphalerites as follows: a a 5.4093 + 0.000456X — 0.000700Y The relation between a and composition of cobalt- iron-bearing sphalerite . is shown in figure 115.2. GEOLOGICAL SURVEY RESEARCH 1961 Approximate limits of sphalerite at 850° C. 35 PERCENT \/ a. , IN ANGSTROM UNITS Unit ce|l edge of iron-bearing sphalerite from Skinner, Barton. and Kullerud (1959) C05 FeS FIGURE 115.2.—Relation of a (in angstrom units) and com- position (mol percent) of cobalt-iron-bearing sphalerites. The unit-cell edges are approximately additive, but the calculated unit-cell edges tend to be slightly smaller than measured ones in cobalt-iron-bearing sphalerites containing more than 75 mol percent ZnS, and larger in ones containing 65 to 75 mol per- cent ZnS. The a is one parameter used by the writer in con- junction with an Fe2Zn ratio to determine composi- TABLE 2.—Um't-cell edges of cobalt-and-iron-bearing sphalerites Composition of sphalerite ' _ _ . ”-18..-- ,fi,_7>_ ‘7 _J_ _ __“7 “_ 77‘fi777_ mfi 77* a, in angstrom units a, m anstrom units _ . 1 (measured) (calculated) Difi‘erenee \\ eight percent Moi percent an' I ( oS FeS Znh’ (‘05 FeS 90. 87 4.63 4 . 50 90.15 4 . 91 4 . 94 5.4084 to . 0002 5. 4082 0.0002 86.30 4.60 9.10 85.19 4.86 9.95 5.4109i .0002 5.4104 —.0005 85. 98 9 . 43 4. 59 85 .00 9. 98 5 .02 5 . 4042 i- .0003 5 . 4046 + . 0004 82.01 13.68 4.31 80.85 14.44 4.71 5.4014i .0002 5.4013 —.0001 81.66 4.51 13.83 80.22 4.74 15.04 5.4130: .0003 5.4129 —.0001 80.82 9.91 9.27 79.47 10.43 10.10 54069 i .0005 5.4066 — .0003 76.81 18.70 4.49 75.45 19.66 4.89 5.3977i .0002 5.3977 .0000 76 76 14 24 9.00 75.28 14.95 9.77 54030 i .0003 5.4033 '1" .0003 76. 75 9.47 13 . 78 75. 13 9 .92 14.95 5 .4084 i .0003 5.4092 + .0008 76.20 5.52 18.28 74.44 5.77 19.79 5.4134: .0007 5.4143 +0009 7234 4.30 23.36 70. 35 4.47 25.18 5.4169 1- .0006 5.4177 + .0008 71.64 19.19 9.17 70.00 20.07 9 , 93 5.3992 i .0005 5.3998 + .0006 71.26 9.60 19.14 69.35 10.00 20.65 5.4113i .0005 5.4117 +0004 71.06 14.76 14.18 69.15 15 37 15.28 5.4046i .0005 5.4055 +0009 4060 24.40 5.00 69.03 25 55 5.41 5.3928: .0007 5.3939 +.0011 65. 77 28.82 5.41 64 09 30 07 5.84 5.3903 i .0002 5.3910 + .0007 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 tion of cobalt-iron-bearing sphalerites in the phase studies. REFERENCES Kullerud, Gunnar, 1953, The FeS—ZnS system. A geological thermometer: Norsk g'eol. tidsskr., v. 32, p. 61—147. 116. B—273 Skinner, B. J., Barton, P. B., Jr., and Kullerud, Gunnar, 1959, Effect of FeS on the unit-cell edge of sphalerite. A re- vision: Econ. Geology, v. 54, p. 1040—1046. Skinner, B. J., and Barton, P. B., Jr., 1960, The substitution of oxygen for sulfur in wurtzite and sphalerite: Am. Mineralogist, v. 45, p. 612—625. 5% X-RAY DIFFRACTOMETER METHOD FOR MEASURING PREFERRED ORIENTATION IN CLAYS By ROBERT H. MEADE, Menlo Park, Calif. The preferred orientation of clay minerals is a key to the understanding of the deposition and com- paction of clayey sediments. This orientation is not always-susceptible to measurement by optical means because (a) individual clay-mineral particles are generally too small to be studied, and (b) many clays, particularly those rich in montmorillonite, have swelling properties that make the preparation of thin sections difiicult. X-ray diffraction provides a way to overcome these difficulties. X-ray diffractometer methods of petrofabric study have been described by Higgs and others (1960), Silverman and Bates (1960), and Kaarsberg (1959, p. 453—454). The method to be described in this article is similar to the one used by Kaarsberg. Its main advantage over previously described methods is that a numerical index is obtained that can be used to compare the orientation of different phyllosilicate minerals in rock specimens from different terranes. BASIS OF METHOD The use of X-ray diffraction in petrofabric study depends on the fact that the intensity of the reflec- tion from any crystallographic plane varies directly with the mass of material oriented so that the plane reflects X-rays according to the Bragg relation. This is illustrated by X-ray diffraction patterns from two specimens of the same clay-mineral frac- tion (fig. 116.1). The first specimen was prepared by allowing the clay-mineral particles to settle out of suspension and lie with their basal planes parallel; the preferred orientation of these clay particles is nearly perfect. All the peaks in the diffraction pat- tern from this specimen (lower pattern, fig. 116.1) represent reflections from basal planes. In the other specimen, prepared with random rather than pre- ferred orientation of the clay minerals, the reflections from the basal planes are less intense. Other crystal- lographic planes within the minerals reflect X-rays, and their peaks also appear in the pattern (upper pattern, fig. 116.1). In the pattern from the specimen that has pre- ferred orientation, the (001) reflection from basal planes of montmorillonite (at 15 A) is much en- hanced and the (020) reflection from planes per- pendicular to the basal planes (at 4.4 A) is absent. On the other hand, in the pattern from the speci- men that is oriented at random, the 4.4—A peak is nearly as high as the one at 15 A. These two peaks are the ones whose heights are used to measure the preferred orientation of montmorillonite particles. Because montmorillonite is the most abundant clay mineral in the sediments that were examined by this method, this article will describe the measurement of its preferred orientation. The same principle, however, can be used to measure the preferred orien- tation of other clay minerals. The samples illustrated in figure 116.1 were taken from a clay-mineral fraction that is especially rich in montmorillonite. The X-ray patterns are ideally simplified because most of the nonclay minerals have been removed, and the orientation of the clay par- ticles was produced artificially. Patterns from natural sediments are not so well defined. PREPARATION AND X-RAY DIFFRACTION From a block of air-dried sample, three small cylin- ders are cut in such a way that their circular ends B—274 GEOLOGICAL SURVEY RESEARCH 1961 ANGSTROMS 4.4 15 I I _4>. _. _ _4 001 020 RANDOM ORIENTATION PREFERRED ORIENTATION FIGURE 116.1.—Efl'ects of particle orientation on X-ray diffraction patterns of clay minerals. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—275 4:1 1‘5 ANGSTROMS 4.4 ’ 15 I l T I I I l I I I I l r 9 I l I I l l l —[ I] 5 10 20 5 IO 20 I HORIZONTAL VERTICAL I VERTICAL II 92 L13 L :23 L _ 62+69 103+11g 84+83 72+71 PREFERRED ORIENTATION RANDOM ORIENTATION FIGURE 116.2.—Measurement of horizontal preferred orientation by comparison of X—ray diffraction peak heights. (Norelco type 52184—A) on the Norelco X-ray dif- fractometer. The plane sections are polished on progressively finer frosted—glass plates without added abrasives as suggested by Weatherhead (1940, form mutually perpendicular planes, one horizontal (parallel to the bedding) and two vertical. The cylinders have diameters of about 2 cm so that they fit snugly into a low-angle rotating specimen holder B--27 6 p. 530). The polished specimens are then placed in the rotating specimen holder, which is mounted on a wide-range goniometer, and exposed to radiation. ORIENTATION RATIO For each section, the (001) and (020) reflections are recorded three times, and average values are used for the peak heights. From the average values the ratio between the heights of the 15—A peak and 4.4—A peak is computed for each section. The peak-height ratio for the horizontal section is then divided by an average ratio for the two vertical sec- tions. The quotient is taken as a measure of the horizontal orientation of the basal planes of mont- morillonite, and is called the orientation ratio. Other factors that affect the intensities of X-ray reflections ——particle size, chemical composition, degree of crystallinity—are cancelled out of the orientation ratio when the horizontal peak-height ratio is di- vided by the vertical peak-height ratios. Figure 116.2 shows the measurement of the orien- tation ratio in two samples, one having preferred orientation and the other having random orienta- tion. In contrast with those in figure 116.1, the pat- terns are complicated by reflections from illite, chlo- rite, and by stronger reflections from quartz and feldspar. The peak heights of montmorillonite have been adjusted (“noise corrected") to eliminate the effects of background reflections. Peak-height ratios are given for each section, and the orientation ratios are computed from them. An orientation ratio of 1.0 indicates completely random orientation with respect to the horizontal; clays having preferred 117. GEOLOGICAL SURVEY RESEARCH 1961 horizontal orientation have orientation ratios larger than 1.0. The orientation ratios given in figure 116.2 measure onlythe preferred orientation parallel to the bedding. The planes may be adjusted, how- ever, to measure the orientation in any directions— parallel to cleavage, schistosity, or other planar elements. The most precise measurements of the orientation ratio are obtained from materials in which one phyllosilicate predominates over all others to the extent that X-ray reflections from the other minerals do not interfere seriously with the reflections from the principal mineral. Reflections from montmoril- lonite, for example, can be masked or modified by (020) reflections from illite at 4.4 A or by (001) reflections from chlorite at 14 A. This method, therefore, should be applied cautiously to rocks that contain heterogeneous mixtures of clay minerals and other layer silicates. REFERENCES Higgs, D. V., Friedman, Melvin, and Gebhart, J. E., 1960, Petrofabric analysis by means of the X-ray diffractome- ter, in Rock deformation (a symposium): Geol. Soc. America Mem. 79, p. 275—292. Kaarsberg, E. A., 1959, Introductory studies of natural and artificial argillaceous aggregates by sound-propagation and X-ray diffraction methods: Jour. Geology, v. 67, p. 447—472. Silverman, E. N., and Bates, T. F., 1960, X-ray diffraction study of orientation in the Chattanooga shale: Am. Min- eralogist, v. 45, p. 60—68. Weatherhead, A. V., 1940, A new method for the preparation of thin sections of clays: Mineralog. Mag., v. 25, p. 529— 533. ’5? MOLYBDENUM CONTENT OF GLACIAL DRIFT RELATED TO MOLYBDENITE-BEARING BEDROCK, AROOSTOOK COUNTY, MAINE By F. C. CANNEY, F. N. WARD, and M. J. BRIGHT, JR., Denver, Colo. A recent survey by Riddell (1960) of the experi- ence of 24 Canadian companies engaged in mineral exploration disclosed a lack of unanimity of opinion concerning the usefulness of soil-sampling tech- niques in glaciated areas. Althoughwidely used, opinion on the value of applied geochemistry ranged from “extremely useful and valuable tool” to “no value whatsoever.” At least part of the negative attitude is attributed to the scarcity of published studies that provide useful data for guiding mineral exploration programs in glaciated areas. The moly- bdenum anomaly described in this paper provides SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 gm 1P: 8 l _. o I 0| 1 H MOLVBDENUM CONTENT, IN PARTS PER MILLION .0 01 B—277 Approximate location /molybden|te-bearing zone ‘ 0 100 200 FEET |—_l—_L—_J FIGURE 117.1.—Geochemical profile showing lateral distribution of molybdenum in glacial drift over molybdenite-bearing zone. Land surface along sample traverse is nearly level. another positive illustration of the usefulness of geochemical prospecting techniques in a glaciated area. A zone of silicified limestone containing easily visible but sparse molybdenite as flakes and thin seams is poorly exposed in a group of prospect pits about 6 miles north-northeast of Houlton, Maine. Detailed mapping by Louis Pavlides (oral communi- cation, 1960) in the Houlton quadrangle has shown this zone to be satellitic to a small intrusive plug of granite. The bedrock in this test area is almost completely covered with glacial ground moraine, 6 to 24 inches thick. Although glacial-fluviatile de- posits are very common in the Houlton quadrangle, the available exposures were insufficient for us to classify the cover as till or stratified drift. The brief investigation described here was designed to determine whether anomalous amounts of moly- bdenum occurred in the soil in the vicinity of this metallized zone. A line 800 feet long was surveyed across the pro- jected trend of the mineralized zone. Soil samples were collected along this line at intervals of 5 feet above and near the suboutcrop of the zone and the spacing between samples was increased progressively to 50 feet as the distance from the deposit increased. The samples were taken from a depth of 8 to 12 inches below the land surface. Because the area had once been cultivated, no original soil profile is pres- ent, but we believe that the samples were from un- disturbed soil below plow depth. Most of the 49 samples collected along this line contained a large percentage of material in the silt- and clay-size range. All samples were dried and sieved through a 100- mesh sieve, and the fines analyzed for molybdenum by a geochemical prospecting field method utilizing a carbonate fusion to decompose the sample (Ward, 1951). The molybdenum contents of the soil samples (fig. 117.1) show that the soil both over and on either side of the exposed part of the mineralized zone contains anomalous amounts of molybdenum (back- ground in this area is 1 to 2 ppm molybdenum). For a distance of more than 80 feet the soil contains more than 8 ppm, and the soil contains 30 ppm or more in one stretch of 35 feet. The soils containing the most molybdenum occur just to the southeast of the exposed zone. Because this zone, which seems to trend northeasterly, is exposed in only a few small trenches, its maximum dimensions as well as the possible presence of other molybdenite-bearing zones are unknown. The rather abrupt decrease in a southeasterly direction from the peak value of 90 ppm to background in less than 150 feet suggests little, if any, glacial drag. In this part of Maine the ice movement-was probably in a south-southeast- erly direction. If the anomaly were formed by dif- fusion of soluble molybdenum upward into the glacial cover after retreat of the ice, no asymmetry due to ice movement would be present. The form in which the molybdenum occurs in the B—27 8 soil is not known. Several samples containing anomalous amounts of molybdenum were leached with hot water, but no molybdenum was found in the leachate; this apparent lack of water-soluble molybdenum could be interpreted as weak evidence that this anomaly is not a superimposed diffusion pattern. Although certain questions about the genesis of this particular anomaly remain unanswered, the point of greatest significance to those engaged in mineral exploration is that this is another example 118. GEOLOGICAL SURVEY RESEARCH 1961 of the usefulness of soil sampling techniques in the search for mineral deposits concealed beneath a thin cover of glacial materials. REFERENCES Riddell, J. F., 1960, Geochemical prospecting methods em- ployed in Canada’s glaciated Precambrian terrains: Min- ing Eng., V. 12, no. 11, p. 1170—1172. Ward, F. N., 1951, Determination of molybdenum in soils and rocks: Anal. Chemistry, v. 23, p. 788. ’R ANOMALOUS HEAVY MINERALS IN THE HIGH ROCK QUADRANGLE, NORTH CAROLINA By AMos M. WHITE and ARVID A. STROMQUIST, Washington, D. C., and Denver, Colo. Work done in cooperation with North Carolina Division of Mineral Resources Heavy-mineral concentrates obtained by panning alluvial sediment from streams in the High Rock 71/2-minute quadrangle, North Carolina, contain minerals anomalous to the known bedrock of the quadrangle. The area investigated lies west of the Atlantic Coastal Plain in Davidson, Rowan, Stanly, and Montgomery Counties, N. C., and is underlain by rocks of the so-called Carolina slate belt, a vol- canic and sedimentary sequence probably of Pre— cambrian and Paleozoic ages in the eastern part of the North Carolina Piedmont (fig. 118.1). Geologic mapping of the area has established for the first time a stratigraphic sequence for the Caro- lina slate belt (Stromquist and Conley, 1959). Out- cropping rocks in the High Rock quadrangle are largely tufi'aceous argillite interbedded with and un- conformably overlain by metamorphosed tuffs, lapilli tuffs, and minor flows, all of rhyolitic to andesitic composition. Diabase dikes and dacitic(?) to gab- broic intrusive bodies are also present. Regional metamorphism of these rocks is low grade, nowhere exceeding the greenschist facies. Metamorphic grade increases west of the slate belt in rocks com- prising the adjoining Charlotte, Kings Mountain, and Inner Piedmont belts (King, 1955, p. 346—356). Forty-pound samples of sand and gravel deposited by the modern streams were collected at 57 localities in the High Rock quadrangle. Each sample was col- lected from the channel of a stream having a drain- age area of 2 square miles or less, and was collected at a point outside the flood plain of the present Yadkin River, the major stream in the quadrangle (fig. 118.1). All the concentrates contain one or more minerals characteristic of the almandine-amphibo— lite facies of regional metamorphism (Fyfe, Tur- ner, and Verhoogen, 1958, p. 228—232). These min- erals are staurolite, kyanite, sillimanite, and garnet. Kyanite is present in 55 of the concentrates, stauro- lite is in 47 concentrates, and sillimanite or probable sillimanite is in 23. Garnet is present in 48 concen- trates and is abundant in many of these. Relatively coarse-grained zircon, much of which shows some degree of rounding, is present in 35 of the concen- trates. At least 13 concentrates contain monazite or probable monazite. In general, the concentrates with the largest suites of anomalous minerals are from streams in the west half of the quadrangle. Most of the kyanite shows some degree of round- ing, and the monazite is well rounded, which sug- gests transport from some fairly remote source. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1—146 81" 80° .———__- ____ VIRGINIA I NORTH CARBLI'NA cbr YadM/n . ‘5. cbr A NORTH CAROLIN ‘ _ _ A I SOUTH CAROLINA‘ ‘ 3OMILES‘ l—l—QJ EXPLANATIONV Rocks of the Charlotte, Kings Mountain, Inner Piedmont, Brevard, and Blue Ridge belts _..-__./ e oastal Plain vu §§ Volcanic and sedimentary rocks ’ 0f the Carolina slate belt Approximate eastern limit of rocks with staurolite, kyanite, and sillimanite (almandine-amphibolite facies) FIGURE 118.1.——Index map of west-central North Carolina showing location of the High Rock quadrangle. Geology generalized from King (1955) and from the geologic map of North Carolina (Stuckey and Conrad 1958). Rounded detrital kyanite denotes a stream of low velocity according to Krumbein and Pettijohn (1938, p. 436), but many of the streams from which the B—27 9 concentrates were obtained have steep gradients and are relatively short and fast moving, particularly those draining the highest points in the quadrangle. The nearest known occurrence of rocks of the almandine-amphibolite metamorphic facies is ap- proximately 30 miles to the northwest, and the Yad- kin is the only stream in the area that extends west- ward to these rocks (fig. 118.1). Presumably the higher grade metamorphic minerals were deposited in sediments along former courses of the Yadkin, possible remnants of which are now preserved on topographically high surfaces in the quadrangle. The small streams in eroding these surfaces pick up the anomalous minerals and redeposit them at lower elevations. The presence of heavy minerals in the surficial materials in the High Rock quad- rangle suggests that regional studies of heavy min- eral distribution would provide data for tracing the former major drainage systems in the region. REFERENCES Fyfe, W. S., Turner, F. J., and Verhoogen, John, 1958, Meta- morphic reactions and metamorphic facies: Geol. Soc. America Mem. 73, 259 p. King, P. B., 1955, A geologic section across the southern Appalachians—an outline of the geology in the segment in Tennessee, North Carolina, and South Carolina, in Russell, R. J., ed., Guides to southeastern geology: Geol. Soc. America, p. 332—373. Krumbein, W. C., and Pettijohn, F. J., 1938, Manual of sedi- mentary petrography: New York, Appleton-Century- Crofts, Inc., 549 p. Stromquist, A. A., and Conley, J. F., 1959, Geology of the Albemarle and Denton quadrangles, North Carolina: Carolina Geol. Soc. Field Trip Guidebook, Oct. 24, 1959, Div. Mineral Resources, Raleigh, N. C., 36 p. Stuckey, J. L., and Conrad, S. G., 1958, Explanatory text for geologic map of North Carolina: North Carolina Dept. Cons. and Devel., Div Mineral Resources, Bull. 71, p. 3—51, map. 5? 119. IRON CONTENT OF SOILS AND TREES, BEAVER CREEK STRIP MINING AREA, KENTUCKY By EUGENE T. OBORN, Denver, Colo. In the Beaver Creek strip mining area, Kentucky, trees growing on the soil through which the mine waters percolate extract iron from the drainage water. This is shown by samples of soil from the root feeding zone and samples of vegetation col- lected at two locations, one upslope and one down- slope from a strip mine opened in May 1955. Sampling of vegetation was restricted to the white B—280 TABLE 1.—-Analyses of white oak plant parts, strip-mine area Iron per gram Iron in ash Location of tree sampled Material analyzed dry matter (percent) (milligrams) Above mine ............... Leave iiiiiiiiiiiiiiiiiii 0,07 011 Do .................... Trunk before 1955 ......... .05 1.72 Do .................... Trunk 1955—60 ............ .07 1.25 Do .................... Bark ..................... . 13 .13 Below mine ............... Leaves ................... .29 .47 Do .................... Trunk before 1955 ......... .04 1,40 D0 .................... Trunk 1955—60 ............ .10 1.79 D0 .................... Bark ..................... .32 .35 oak, Quercus alba L. Wood and bark were sampled in duplicate with a large-diameter increment borer. Analyses of the samples are given in tables 1 and 2; the results are summarized below. Iron content, on a dry-matter basis, in the wood of trees growing both upslope and downslope from the mine is greater in wood produced from 1955 to 1960 than in wood produced earlier. The iron con- tent is greatest in the 1955 to 1960 wood of the downslope tree which received drainage from the mine. The iron content in ash of the wood from the tree above the mine is greater for the period pre- ceding 1955 than it is for the period 1955 to 1960. The reverse is true for the downslope tree. These data indicate that from 1955 to 1960 iron was more readily available and absorbed by the downslope tree than was the case with the upslope tree. As determined by analyses of the dry matter, in the downslope trees the iron content of the leaves is four times, and the bark is more than two times, the iron content of the corresponding parts of the upslope trees. Analyses of the ash of the leaves and bark also shows a greater concentration of iron in the ash of these parts of the downslope trees than in the upslope trees. It is usually true in woody 120. GEOLOGICAL SURVEY RESEARCH 1961 TABLE 2.—Analyses of soil in the root feeding zone, strip mine area Total iron content of Iron in fresh dry soil soil extract 1 Location of Moisture Organic (milligrams (parts per pH of sample (percent) matter per gram) milllon) extract (percent) 62°C 575°C Fe”I Fe” Above mine, in treeroot feeding zone ............ 6.0 6.13 6.81 7.28 0.11 0.07 6.7 Below mine, in treeroot feeding zone ............ 9.6 l 5.37 5.96 6.28 .04 .02 4.3 1 Extract made by mixing 100 ml of distilled water and 1.0 g of fresh soil. Filtered after 1 hour. plants that leaves and bark have a greater concen- tration of iron than does the wood. Leaves and bark slough off regularly, hence only recent accumulations of iron are shown by the analyses of these plant parts. The soil sample taken from the root feeding zone below the strip mine contained less iron than the sample taken from the slope above the mine. At both sites the ferrous—iron concentration in the fresh- soil extracts is about double the corresponding ferric- iron concentration. The water-soluble (and thus readily Ieachable and physiologically available) iron in soil from the root feeding zone of the tree below the mine is only about one third that of the soil from the root-feeding zone of the tree above the mine. This was true in spite of the fact that the extract of soil from below the mine had a pH of 4.3 whereas the soil extract from above the mine had a pH of 6.7. The moisture content of the soil sample taken below the mine was greater than that of the sample taken from the upslope location. MINERALOGY OF THE OLIVE HILL CLAY BED, KENTUCKY By JOHN W. HOSTERMAN and SAM H. PATTERSON, Beltsville, Md. Work done in cooperation with The Olive Hill clay bed of Grider (1913) in north- eastern Kentucky contains three types of clay—flint, semiflint, and plastic—in irregular lenses of vari- the Kentucky Geological Survey able thicknesses. Boundaries between types of clay are usually sharp and well defined, and the clay bed is nonbedded except for the superposition of one SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 type of clay above the other. Typically, the flint clay overlies the semiflint clay, but at many places this order is reversed. Where plastic clay is present it is usually in the lower part of the bed, but there are exceptions. Much of the clay is medium gray to brownish gray, but colors may range from very light gray to almost black. The darker gray colors are due to carbona- ceous material of fossil roots, and occur at the top of the clay bed which underlies a thin coal bed. The lighter colors occur toward the base of the bed. Reddish-brown staining of iron oxides along joints is quite common. / Flint clay in the Olive Hill clay bed is hard, resist- ant, and nonplastic. It'possesses the flintlike char- acteristics of almost complete homogeneity and con- choidal fracture. Oolites are very abundant in some of the flint clays. The flint clay weathers to shard- like fragments having sharply curved knife edges and pointed corners. It is composed of more than 85 percent kaolinite and less than 15 percent illite and mixed-layer clay minerals. Boehmite has been found in the flint clay at only one locality. Plastic clay in the Olive Hill clay bed is quite plastic after it has been exposed to weathering for a short time, but the fresh clay requires grinding before maximum plasticity is developed. Abundant slickensides are present in the fresh plastic clay, but after the clay weathers the slickensides become sealed and disappear and the clay becomes a homo- geneous mass. The plastic clay is composed of less than 60 percent kaolinite; illite and mixed-layer minerals make up the balance. Semiflint clay is intermediate between flint and plastic clay in physical properties and mineral com- position. Nearly all semiflint clays contain abundant randomly oriented slickensides along which partings may occur. When exposed to the weather, semi- flint clay breaks down into rubble of irregular poly- hedra having a slickenside surface on each face. Semiflint clay consists of 60 to 85 percent of kao- linite; illite and mixed-layer minerals form the balance. The sedimentary nonclay minerals are quartz, tourmaline, garnet, ilmenite, and magnetite. Authi- genic minerals are siderite and pyrite. Fine-grained anatase is also present, but the time of its formation is not known. The mineralogy of the Olive Hill clay bed has been interpreted primarily from X-ray diffraction traces supplemented by differential thermal analysis and petrographic microscope studies. The diffraction traces of oriented and random specimens of several B—281 W w 40° 30° 20° 10°29 FIGURE 120.1.—X-ray diffraction traces using CuKa radiation. A, well-crystallized kaolinite in flint clay; B, kaolinite and boehmite in flint clay; and C, poorly crystallized kaolinite and illite in plastic clay. samples were obtained using CuKa radiation. Ori- ented specimens were heated to 550°C for 30 min- utes, heated to 300°C for 30 minutes, treated with ethylene glycol, and X—ray dried. Kaolinite in the Olive Hill clay bed ranges from well crystallized in the flint clay to poorly crystal- lized in the plastic clay, with intermediate stages of crystallinity in the semiflint clay. Well-crystallized kaolinite has a narrow basal (001) peak, which has an area-to-height ratio that approaches 1 in the X-ray diffraction trace at 7.14A (fig. 120.1A). Poorly crystallized kaolinite or “fireclay” (Brindley and Robinson, 1947) has a broad basal (001) reflec- tion at about 7.20A and the area-to-height ratio of the peakis almost 2 in the X-ray diffraction trace (fig. 120.10). The well-crystallized kaolinite occurs in samples having a small amount of other clay minerals, and the poorly crystallized kaolinite is B-282 \\ g5 //// \\ l / 100° 200° 300° 400° 500° 600° 700° 800° 900° 1000°C FIGURE 120.2.——Differential thermal-analysis curves. A, well- crystallized kaolinite in flint clay; B, kaolinite with boehmite in flint clay; C, medium—crystallized kaolinite in semiflint clay; and D, poorly crystallized kaolinite in plastic clay. associated with abundant illite and mixed-layer clay minerals. Differential thermal-analysis curves support the above determinations of the kaolinite. The endo- thermic peak of kaolinite occurs at approximately 600°C for flint clay (fig. 120.2A) and at about 580°C for plastic clay (fig. 120.2D). Also, the exothermic reaction at about 975°C occurs over a 25° interval for flint clay and over a 75° interval for plastic clay. The differential thermal curve for semiflint clay is intermediatebetween flint and plastic clay (fig. 120.2C). The temperature of~the endothermic peak indicates that more energy is required to break the GEOLOGICAL SURVEY RESEARCH 1961 hydroxyl ion bonds in the flint clay than in the plastic clay. The exothermic peak suggests that the strength of the bonds holding the final structure of the kaolinite is more uniform and tends to re- lease suddenly in the flint clay but not in the plastic clay. Boehmite, a mineral usually found in bauxite, but also found in the flint clays of central Pennsylvania (Bolger and Weitz, 1952), has been recognized in two samples taken from the strip mine on Grassy Creek about 1 mile west of Kehoe, Greenup County, Ky. It occurs as nodules 1/2 to 1 millimeter in diam- eter in a matrix of flint clay. The major X-ray dif- fraction peaks of boehmite (fig. 120.18) are 6.23A, 3.53A, 3.16A, and 2.34A. The differential thermal- analysis curve (fig. 120.23) shows a single endo- thermic peak at 525°C. Illite is the second most common clay mineral in the Olive Hill clay bed. The amount ranges from a trace in the flint clay to about 40 percent in the plastic clay. Illite is recognized on the X-ray diffrac- tion traces by its basal (001) peak at about 10A (fig. 120.10). Only the clay mineral that gives this sharp peak and does not expand when treated with ethylene glycol is considered to be illite. The presence of illite is shown on the diiferential-thermal-analysis curves by the broad weak endothermic reaction between 100°C and 200°C and by the small endo- thermic reaction beginning at 450°C (fig. 120.2D). Mixed-layer clay minerals consist of a heterogen- eous mixture of illite, montmorillonite, chlorite, and probably some vermiculite. X-ray diffraction traces of these minerals have a broad diffuse peak in the 10A to 14A range, and the position of this peak is changed very little with ethylene glycol or heat treatments. These mixed-layer clay minerals are present in all types of clay but are most abundant in the plastic and semiflint clay. REFERENCES Bolger, R. C., and Weitz, J. H., 1952, Mineralogy and origin of the Mercer fire clay of north-central Pennsylvania, in Problems of Clay and Laterite Genesis: Am. Inst. Mining Metall. Engineers Symposium, p. 81—93. Brindley, G. W., and Robinson, K., 1947, An X-ray study of some kaolinitic fire clays: British Ceramic Soc. Trans, v. 46, p. 49—62. Crider, A. F., 1913, The fire clays and fire clay industries of the Olive Hill and Ashland districts of northeastern Kentucky: Kentucky Geol. Survey, ser. 4, v. 1, pt. 2, p. 592—711. 5% SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 121. B—283 ' FOUR ENVIRONMENTS OF THORIUM-, NIOBIUM-, AND RARE-EARTH-BEARING MINERALS IN THE POWDERHORN DISTRICT OF SOUTHWESTERN COLORADO By D. C. HEDLUND and J. C. OLSON, Denver, Colo. Geologic mapping and radioactivity investigations in the Powderhorn district, Gunnison County, 0010., show that the thorium, rare earths, and niobium deposits of the district are related to alkalic intrusive rocks, probably of Precambrian age, that cut diverse Precambrian rocks. The alkalic rock complex of Iron Hill, which has been mapped and described by Larsen (1942), occupies an elliptical area of about 12 square miles and is economically the most im- portant intrusive body in the district. The rocks in the complex from oldest to youngest are pyroxenite, uncompahgrite, ijolite, diverse hybrid pyroxenite- syenite rocks, nepheline syenite, gabbro, and car- bonatite. Locally at the borders of the complex is a syenite that is interpreted to be fenite, or metaso- matically altered granite. The carbonatite, the youngest rock of the intrusive series, underlies an area of 2 by 1% miles at Iron Hill. Many carbonatite dikes radiate from the main carbonatite mass and cut all the other rock types of the complex. Four rock types in the Powderhorn district (fig. 121.1) that have radioactivities appreciably higher than background and contain thorium, niobium, or rare earths in abnormal amounts are (a) carbona- tite, (b) magnetite-ilmenite-perovskite bodies, (c) thorite veins, and (d) trachyte porphyry dikes. Carbonatite dikes are the most radioactive rocks within the alkaline complex of Iron Hill. Of 214 carbonatite dikes examined; 132 have radioactivities ranging from 0.05 — 0.70 mr per hr or 2 to 35 times background. These more radioactive dikes generally contain layers of siderite or ankerite alternating with layers of dolomite, calcite, or biotite. They also contain pyrite and moderate to very minor amounts of barite, apatite, monazite, quartz, bastnaesite, and synchisite, and commonly weather to a chocolate- brown color. In contrast, the less radioactive car- bonatite dikes, with radioactivity less than twice background, generally are homogeneous, contain dolomite, quartz, calcite, and biotite with only sparse pyrite and apatite, and weather to buff or rusty yellow colors. The thorium in the carbonatite is, in part at least, in reddish-brown monazite which has an equivalent thoria content of 0.5 — 0.6 percent. Rare earths occur as monazite, as the fluocarbonates synchisite and bastnaesite, and substitute for cal- cium in the apatite. Analyses of the carbonatites are summarized in figure 121.2. The carbonatite stock of Iron Hill is less radio- active than the carbonatite dikes and has a maxi- mum radioactivity of about 0.10 mr per hr, or 5 times background. The radioactivity is due chiefly to thorium in monazite( ?), pyrochlore, and perhaps other minerals. The magnetite-ilmenite-perovskite veins, dikes, and segregations make up a very small percentage of the total outcrop area in the pyroxenite, ijolite, and uncompahgrite of the alkaline complex of Iron Hill, chiefly in the parts of the complex north of Iron Hill. The magnetite-ilmenite-perovskite veins and dikes are discontinuous and generally occur in swarms; most are less than 2 feet thick but some are as much as 150 feet thick. The magnetite, ilme- nite, and perovskite also occur as disseminated dis- crete grains within the pyroxenite, ijolite, and un- compahgrite and are generally more abundant in the coarser grained rocks. The radioactivity of the magnetite-ilmenite-perov- skite bodies at 128 localities ranges from 0.05 to 0.25 mr per hr or 2 to 12 times background. This radioac- tivity is attributable to thorium in the perovskite, concentrates of which have an equivalent thoria con- tent of 0.12 to 0.15 percent. In transmitted light the perovskite is dusky purple, strongly twinned, and anisotropic. The perovskite content of the magnetite- ilmenite-perovskite bodies is highly variable and locally is as much as 50 percent. The thorite veins, which occur outside the complex of Iron Hill, constitute the third and most radio- active type of rare-metal concentration in the Pow- derhorn district. About 217 thorium-bearing veins have been examined, and 96 of these veins have radioactivities in the range of 0.15 to 5.0 mr per hr or 5 to 250 times background. These veins cut the amphibolite, quartz—biotite schist, granite, and other Precambrian rocks outside of the complex of Iron Hill and tend to be more abundant in the vicinity of the complex and outlying syenitic bodies. The thorite veins are generally less than a foot thick and com- monly occur in anastomosing shear or breccia zones up to 10 feet wide. The veins are discontinuous, rarely as much as 3,500 feet long, and preferentially strike N. 45°—60° W. and N. 60°—80° E. B—284 GEOLOGICAL SURVEY RESEARCH 1961 107°15’ l' A A : / A } AA" 'A / A ‘ A‘ A I. 38°20’ ‘ EA iv A \ \ \-. A '\ AM \ EXPLANATION .Q Complex of Iron Hill and other syenitic rocks Deposits with radioactivity greater than 0.1 mt per hour Carbonatite A + Thorite vein Trachyte porphyry dike X 0 Magnetite ilmenite- perovskite rock 1 O 7 ° 00’ K - _ " 1 O DENVER X . \ Gunnison I L) .0 o Pueblo '7. ' (i l \___ \ t T \ “A \VulcanV / .. / \u \ l ‘ - \1 “1an Hill M \ 2 MILES FIGURE 121.1.—Generalized map of part of Powderhorn district, Colorado, showing locations of thorium-bearing deposits. The thorium-bearing veins consist of orthoclase, | characteristic of the radioactive minerals of the alk- quartz, barite, specular and earthy hematite, goethite, thorite, thorogummite, calcite, dolomite, fluorite, bio- tite, sodic amphibole, pyrite, chalcopyrite, galena, and sphalerite. Commonly the wall rocks have been partly replaced by orthoclase, and fragments of the resulting syenitic rock have locally been incorpor- ated in the veins. From the analyses (fig. 121.28) it is apparent that the thorite veins are character- ized by relatively large amounts of Th, Ba, Sr, rare earths, Nb, and alkalies, an assemblage that is also alic rock complex of Iron Hill. The fourth type of radioactive deposit consists of pink to red fine-grained trachyte porphyry dikes which also cut various Precambrian rocks of the district outside the complex of Iron Hill. About 100 dikes have been mapped, chiefly in the vicinity of . the complex. The dikes, which are generally less than 50 feet thick but locally as much as 75 feet thick, are discontinuous, branching, and locally fol- low joint planes in the country rock. The trachyte SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—285 j I I I I I I I I ‘I I I I I I I I I I I I I I I I I _ a I.5 6 I _M I 3 2 5 2_ k— Rare-earth elements fl _ 7 2 I5 7 7 I II I I s5 13 _ I 2 2 I .3 2 _|_5 -2 I __ 2.! 2 3 2 a -07 I.0 3 I 9 .2 e 7 e -03, _ I— z e I 9 I .3 3 I _on P _! ‘.4 I I I § 7 —— -007 g __ 2 45255—3 ! 5-003 5 _ 3 I 5— 3 .2 3 3 3 .0015 0' — I 6 __ _2— _ —o.oo7 _ — ‘~? _ _? g—oooa - l — 3 -0.00|5 — — _—' 2 —o.ooo7 — _ "2 —o.ooos 2 I 7©©®CM®©®®©®®©®®®®CO®€D®® “0-000‘5 l l I 1 | I I I I I l I I I i I l I l l I l l I NaMgPKCaTiFeSrYNbBaLaCePrNdSmEquTbDyHoErTmYbLuQ" Atomic No. 11 12 15 19 20 22 26 38 39 41 56 57 58 59 60 62 63 64 65 66 67 68 69 70 71 fi 0 A. CARBONATITES FROM IRON HILL COMPLEX (21 ANALYSES) I I I l I I I I I I I I I I I r I I I I I I I I I I _ 3 II 7 .7 _M _ I If: 5 |_4 §|<———Rare-earth elements‘fl _7 _5947I.II2.0 7 I_3 _ :4 2 2 I? .3 2 as 77 ! I _.5 _.7 4_I_27II 5!.2 :I 2.07 '9 I? .7 I.3 5 4 I 9 I 5 I 5 :2 3 -03 II 6—— 4 e e I 2 e a 3 4 4 I 2 I 4 - . . . o . . . . . . - . . - . _O.‘5 .— 4 II 3 9 I5 8 4 4 9 IO 3 l5 6 4 4-— l I l 8 _ z _ . . . . . . . . . . . . . . . . . 0.07 m — —- - - o _ .7 I 4 I9 $9I.3I.0I .7I.2.3I.I II L003 5 _? ? §II'$§?—!?Z.§? II I? I 5_o_o,5a I. I I 7 .5 4 —— 2 5‘I-7—(I— -01007 _ I _ 2 8 9 4 I. — {I I .0003 — - g — g3 —0.00|5 __._ l2 - — - —0.0007 _ _ ! ‘I '. g 9 5 _00003 — _ _ 3 *HWCD®@©@@©®®®®®@@®@ _-0-000I5 I I I l I I l l J I I I l I I I I l l I l l NaMgPKCaTiFeSrYNbBaLaCePrNdSmEquTbDyHoErTmYbLud' Atomic No. 11 12 15 19 20 22 26 38 39 41 56 57 58 59 60 62 63 64 65 66 67 68 69 70 71 'fi Q} B. THORIUM-BEARING VEINS (47 ANALYSES) FIGURE 121..2—Distribution of semiquantitive Spectographic analyses and radiometric (eThOg) analyses of carbonatite (A) and thorium-bearing veins (8) from Powderhorn district, Colo. The numbers indicate the number of analyses in which a given element is present in the percentage shown. The approximate limit of detection by this analytical method is shown by a horizontal dash, although a few determinations were made below this limit; the number of samples in which percentages are below this threshold amount and too low to determine is indicated by number in circle. Equivalent thoria was determined radiometrically and adjusted to scale of percentages used for spectrographic data. B—286 porphyry dikes are generally radioactive with read— ings of 0.04 — 0.08 mr per hr or 2 to 4 times back- ground. About 20 of the dikes have radioactivities between 0.05 and 0.3 mr per hr, and one has as much as 5.0 mr per hr. In the rock studied, the radio- activity is concentrated in hematite pseudomorphs after pyrite pyritohedrons and may be due to ex- tremely fine-grained intergrown thorogummite. Features that characterize most of the four types of radioactive deposits and indicate their genetic relation include (a) the amounts of such elements as Th, rare earths, Nb, Ba, Sr, which are well above that of most igneous rocks; (b) the spatial relation to the environs of the complex of Iron Hill and smaller bodies of syenitic rock in the district; (c) a fetid odor like garlic that locally characterizes freshly broken rock from thorite veins, trachyte dikes, and fenitic rocks; and (d) alkali metasomatism or re- placement of wall rocks by orthoclase, which is especially characteristic of the thorite veins and less so of the trachyte dikes. Along the borders of the 122. GEOLOGICAL SURVEY RESEARCH 1961 alkaline complex of Iron Hill the granitic country rocks are locally feldspathized to form soda syenite (fenite), implying the introduction of Na rather than K. The four types of thorium-rare-earth-niobium con- centrations are thought to have been formed during the late stages of emplacement of the Iron Hill stock and related syenitic rocks. Within the complex of Iron Hill, the magnetite-i1menite-perovskite bodies are among the youngest rocks, and the stock and dikes 0f carbonatite are the youngest. Inasmuch as the thorite veins and trachyte dikes are known only outside the complex, their age in relation to the main massof the complex is uncertain, but the similar features mentioned above suggest they also formed late in the sequence of the alkalic rocks. REFERENCE Larsen, E. 8., Jr., 1942, Alkalic rocks of Iron Hill, Gunnison County, Colorado: U.S. Geol. Survey Prof. Paper 197—A, p. 1—64. 6% RHENIUM IN PLANT SAMPLES FROM THE COLORADO PLATEAU By A. T. MYERS and J. C. HAMILTON, Denver, Colo. In a recent review of the geochemistry of rhenium, Fleischer (1959) pointed out that our present knowl- edge rests almost entirely on the work of the Nod- dacks (1931), with the exception of new analyses of molybdenite and a few other determinations. He pointed out that no mineral other than the moly- bdenum minerals, molybdenite and wulfenite, has been reported to contain as much as 2 ppm (parts per million) rhenium. The close association of rhenium with molybdenum is further confirmed by the fact that in nearly 1,000 analyses of ores and smelter products, Kaiser, Herring, and Rabbitt (1954) found rhenium in only three, all of which were molybdenite ores or concentrates. Rhenium was discovered for the first time in uranium ore from Triassic sedimentary rocks of the Colorado Plateau by Peterson, Hamilton, and Myers (1959) ; it was associated with the molybdenum min- erals jordisite(?) and ilsemannite. Helen Cannon (oral communication, 1960) had noted that Astraga- lus and other plants from the Yellow Cat area of Grand County, Utah, contained relatively large amounts of molybdenum, in addition to toxic amounts of selenium. These are the so-called “indi- cator” plants used by her as a prospecting guide to uranium mineralization. With the above geochemical association in mind, several plants from soils rich in uranium and molybdenum were analyzed and found to contain rhenium in the ash. This is the first time rhenium has been found in plants. Helen Cannon provided many plant samples she collected from the Yellow Cat area in Utah. Other plant samples were collected by P. F. Narten, C. M. Mobley, Frank Kleinhampel, Fred Ward, Harry N akagawa, and Henry Bell, III. A preliminary state- ment of the results presented below has been pub- lished (Myers and Hamilton, 1960). The analyses, reported by numbers on a semiquan- titative basis, were obtained by the method of Myers SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—287 TABLE 1.—Rhenium and some other elements in plant ash 1 [In parts per million; . . . , not looked for; d, detected, but concentration uncertain] Pl A h Labrgitory Plant pgfit (poi-scent) Re I Mo Cu Ni V U ‘ So ‘ Locality Yellow Cat area, Grand County, Utah 56—2308 Grindelia fastigiata (gum weed).. . Tops. . . 8.2 150 1500 150 7 30 10 100 McCoy group _ (schroecklngerite deposit). 56—2309 . . . .do ......................... Roots. . 6.4 <50 1500 300 15 150 ............ Do. 59—317B Astragalus preussi (poisonvetch). ._ Tops. . . ....... 150 700 150 15 7 ............ Do. 57—1811 Astragalus pattersom' (locoweed). . . .do. . . . 21.8 70 300 70 30 70 61 1500 Do. 32—60 Ephedm viridis (Mormon tea). . . . . ,do. . . . 9.6 150 150 15 15 70 ............ Do. 33—60 Atriplez confertifolia (shadscale . salt bush) ................... . .do. . . . 26.3 300 300 15 15 30 ............ Do. Gypsum Valley, Montrose County, Colo. D—71417 Astragalus pattersoni (locoweed). . Tops 18.7 70 30 70 7 70 4 400 Gypsum claim. D-71419 ...do ......................... ,.do.. 15.2 70 7 70 7 70 1 400 Do. D-71420 . .do ......................... . .do. 18.4 300 7 70 7 70 2 1900 Do. _ D-71438 . .do ......................... . .do. 28.6 d 300 70 15 300 33 1800 Terrible claim. DD-71441 . , .do ......................... . .do. 168 70 70 70 15 30 4 36 Do. D-71-135 Eriogonum inflatum (desert trumpet .................... do. . 7.4 70 15 150 15 7 3 0.5 Do. D-71436 ..do ......................... .do.. 6.2 150 15 150 15 70 3.2 1.0 Do. D-71437 . .do ......................... do. . 7.5 70 15 150 7 30 4 28 Do. Grants area, Grant County, N. Mex. D—71142. Astragalus confertiflorus (?) ...... Tops. . . 8 . 9 d 30 . 150 15 70 2.5 560 D-71146 Mentzelia pumilis (stickleaf) ..... . .do, . . . 13.4 d 15 300 30 300 25.2 100 D-71147 Onothera caespitosa (primrose). . . . . .do. . . . 17,6 150 70 300 30 300 33.6 300 1 Semiquantitative spectographic analyses, J. C. Hamilton, analyst, method of Myers and others (1961). Chemical analysis for U, E. Fennelly, G. Burrow, and C. Huffman, analysts; method of Grimaldi and others (1954, p. 195). Chemical analysis for Se reported on a dry weight basis, H. Crow, and others (1961). The plant samples were origi- nally ashed overnight in a muffle furnace at 550°C. Ashing experiments made on a number of plant samples for a shorter time interval (3 hours instead of overnight) indicated very little if any loss by the longer ashing period. Analyses of the rhenium-bear- ing samples are listed on table 1. Mr. J. D. Stephens, Kennecott Copper Corp., Salt Lake City, Utah, has advised us (written communi- cation, 1960) that rhenium oxide begins to volatilize at 375°C. Therefore, it is possible that there may be a slight loss of rhenium during the ashing process at 550°C if it is present as the oxide. When the ashing temperature was lowered to 450°C for one hour, the final result for rhenium content showed little if any change. ‘ Spectrographic and chemical results are shown on table 1 for 5 different plant samples, including 4 different plant species, growing in a small schroeckin- gerite deposit in the Yellow Cat area of Utah. Rhen- ium was detected in all 5 different plant tops and 4 different plant species; it was detected in the tops, C. Thompson, E. Smith, W. Bowles, Jr., G. Burrow, and W. Meadows, anal- ysts: methods of Association of Official Agricultural Chemists (1950, p. 416—419). but was not detected in the roots of 1 sample of Grindelia (gum weed). The rhenium content ranges from about 50 to 500 ppm in the ash of these plants. An Atriplex (shadscale salt bush) plant contains about 300 ppm rhenium. The data show little appar- ent correlation of rhenium content with other ele- ments listed on table 1. Analyses are shown on table 1 for 8 plants, in- cluding 5 Astragalus and 3 Eriogomtm, growing in uraniferous ground in the Gypsum Valley area of Colorado. The rhenium content ranges from about 50 to 500 ppm in the ash of these plants. One Astragalus pattersom’ plant contained about 300 ppm in the ash. There is no apparent correlation of rhenium with any of the other elements listed on table 1. With the exception of one Astragalus sample (D—71438), the plants all contained significantly less molybdenum than the plants that grew in the schroeckingerite deposit in the Yellow Cat area. Table 1 shows analyses for three rhenium-rich plants growing in mineralized ground in the Grants area, New Mexico. These samples, like the Gypsum B—288 TABLE 2.—Samples in which rhenium was not detected [Rhenium less than 50 parts per million] Number of analyses Area. Uranium-mineralized ground (105 plants analyzed) 6 plants (5 species) ...... Yellow Cat area, Grand County, Utah. 73 plants (7 species)_,,._.Gypsum Valley, San Miguel and Mont- rose Counties, Colo. 17 plants (11 species)....Grants area, McKinley County, N. Mex. 3 plants (3 species) ...... Paradox Valley, Montrose County, Colo. 3 plants (1 species) ______ Marysvale, Piute County, Utah. ‘3 plants (1 species) ______ Elk Ridge, San Juan County, Utah. Ban-en ground (39 plants analyzed) 34 plants __________________________ Death Valley, Inyo County, Calif. 3 plants (2 species) ______ Southern Black Hills, Fall River County, S. Dak. 2 plants (2 species) ______ Paradox Valley, Montrose County, Colo. Valley plants, contained significantly less moly- bdenum than the plants from the schroeckingerite deposit. Samples that contained no detectable rhenium are grouped on table 2 according to locality. Six plants that are listed as growing in uranium-mineralized ground at the Yellow Cat area were not growing over the schroeckingerite deposit; plant species analyzed in this group included Astragalus confertifloms. Rhenium could not be detected in 73 plants from mineralized areas at Gypsum Valley (table 2). In- cluded in these plants were 7 different species in- cluding Astragalus from the following claims: Pooch, Pay Day, Terrible, Rambler, Gypsum, and American Eagle. In order to test the repeatability of both the ash- ing and spectrographic method, four of the plant samples were reashed and analyzed a second time for Re, Mo, Cu, V, and Ni. The results are shown in table 3 for samples 56—2308, 59—317B, D—71417, and D—71438. 5? GEOLOGICAL SURVEY RESEARCH 1961 TABLE 3.—Compam‘so‘n of results from duplicate ashing of plant samples [In parts per million; . . . not looked for; d, detected but concentration un- certain] Ash Sample No. (percent) Re Mo Cu Ni V 56—2308A ........ 8 . 2 150 I500 l50 7 30 56—23081?) ........ 8 . 5 150 1500 150 7 30 59-317BA ................. 150 700 150 15 70 59—317BB ....... ll .3 150 700 300 15 70 D—7I4I7A. . . . . .. 18. 7 70 30 70 7 70 D—7l4l7B ....... 19.8 d 30 150 7 30 D—71438A ....... 27 . 3 d 300 70 15 300 D—7l438B. . . . . .. .......... d 300 70 15 300 The data so far gathered seem to indicate that the plant tops (or leaves) are more likely than the stems or roots to show the presence of rhenium in min- eralized soil. REFERENCES Association of Ofiicial Agricultural Chemists, 1950, Official methods of analysis, 7th ed.: Washington, D. C., 910 p. Grimaldi, F. S., and others, compilers, 1954, Collected papers on methods of analysis for uranium and thorium: U.S. Geol. Survey Bull. 1006, 184 p. Fleischer, Michael, 1959, The geochemistry of rhenium with special reference to its occurrence in molybdenite: Econ. Geology, V. 54, p. 1406—1413. Kaiser, E. P., Herring, B. F., and Rabbitt, J. C., 1954, Minor elements in some rocks, ores, and mill and smelter prod- ucts: U.S. Geol. Survey TEI—415, 119 p., issued by U.S. Atomic Energy Comm. Tech. Inf. Serv., Oak Ridge, Tenn. Myers, A. T., Havens, R. G., and Dunton, P. J. 1961, A, spectrochemical method for the semiquantitative analysis of rocks, minerals, and ores: U.S. Geol. Survey Bull. 1084—1. Myers, A. T., and Hamilton, J. C., 1960, Rhenium in plant samples from the Colorado Plateau [abs]: Geol. Soc. America Bull., v. 71, p. 1934. Noddack, Ida, and Noddack, Walter, 1931, Die Geochemie des Rheniums: Zeitschr. phys. Chemie, v. A154, p. 207—244. Peterson, R. G., Hamilton, J. C., and Myers, A. T., 1959, An occurrence of rhenium associated with uraninite in Co- conino County, Ariz.: Econ. Geology, v. 54, p. 254. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 123. B—289 CLASSIFICATION OF ELEMENTS IN COLORADO PLATEAU URANIUM DEPOSITS AND MULTIPLE STAGES OF MINERALIZATION By A. T. MIESCH, Denver, Colo. Chemical elements in sandstone-type uranium de- posits of the Colorado Plateau have been classified into two broad groups: (a) dominantly intrinsic elements, or elements whose presence in the deposits is largely unrelated to the process of uranium min- eralization, and (b) dominantly extrinsic elements, or elements whose presence in the deposits is largely a result of uranium mineralization or related proc- esses (Shoemaker and others, 1959, p. 35). Elements that are dominantly intrinsic and those that are dominantly extrinsic can generally be distinguished empirically by their relative abundances in uranium ore and unmineralized sedimentary host rocks. Ex- trinsic components of various elements were intro- duced into the host sandstone and mudstone to form the present deposits epigenetically, but were not necessarily introduced at the same time nor by exactly the same process. Elements that are domi- nantly intrinsic in uranium deposits in the Salt Wash member of the Morrison formation include silicon, aluminum, calcium, magnesium, sodium, potassium, antimony, boron, beryllium, carbon, chlorine, chromium, fluorine, gallium, manganese, phosphorus, scandium, strontium, and titanium. Dominantly extrinsic elements in these deposits, in addition to uranium, include arsenic, cobalt, copper, molybdenum, nickel, lead, selenium, silver, vanadium, yttrium, and zinc. Several elements, including iron, barium, and zirconium, seem to be about equally in- trinsic and extrinsic in deposits in the Salt Wash member. Examination of the co-variation of extrinsic ele- ments among uranium deposits in the Salt Wash member shows that they may be classified further into geochemically coherent'groups and subgroups (fig. 123.1). Deposits rich in one of the elements tend to be rich in the other elements of the same subgroup. The classification of extrinsic elements into coherent groups and subgroups has been ac- complished through computation of linear correla- tion coefficients between logarithms of element con- centrations in samples from 215 deposits. Every ele- ment within a subgroup has a moderate or higher correlation with each of the other elements in the subgroup (fig. 123.1). Elements in the same group, but in different subgroups, have moderate or weaker correlations with each other. All correlations be- tween elements in different groups are less than moderate. Elements in Group I (fig. 123.1) have moderate or nearly moderate correlations with iron, and none has a moderate or higher correlation with aluminum. Elements in Group II have moderate or nearly moderate correlations with aluminum,'but their correlations with iron are lower than moderate. Elements in Group III and IV, yttrium and uranium respectively, do not have moderate or higher corre- lations with any of the other dominantly extrinsic _‘ Group | // Subgroup A / / / /// ~ Fe\ r // \\ Se \\ \4 Group I Group | Subgroup B Subgroup C . Group II /Ag //// Subgroup A CU ‘ \ Pb \\\ L l / \ i / \. . Group II V) ] Subgroup B L Group ”I Y Group W U Very high correlation (r>0.75) High correlation (0.75 > r>0. 50) Moderate correlation (0.50 >r>0.35) FIGURE 123.1.—Groups of coherent elements in uranium ores from the Salt Wash member of the Morrison formation. B—290 elements studied. Examination of the low correla- tion coefficients, however, indicates that both yttrium and uranium in the deposits have greater affinities for the Group I elements than for the Group II elements. ‘ All elements in Group I, in addition to iron, tend to be more highly concentrated in uranium deposits of the Salt Wash member of the Morrison formation on the western and northwestern parts of the C010— rado Plateau, and in this respect their distributions correspond to the distribution of tuffaceous materials in unmineralized sandstone of the Salt Wash, as determined from lithologic data of R. A. Cadigan (written communication, 1958). Copper, silver, and lead, in Group II, are distinctly more highly concen- trated in uranium deposits in the structurally de- formed region of the salt anticlines in western Colo- rado and eastern Utah, a region where vein-type copper-silver deposits are known to occur and where the sandstone of the Salt Wash member tends to con- tain more copper (and possibly other elements) than sandstone of the same unit elsewhere on the Plateau. Zinc, in addition to being more highly concentrated in deposits on the western and northwestern parts of the Plateau, also tends to be highly concentrated in deposits within the salt anticline region. Vana- dium is, in general, more highly concentrated in de- posits on the eastern part of the Plateau. The re- gional distribution of uranium in the deposits has not been determined; the samples which were studied are biased with respect to uranium grade, and the distribution of uranium assays on a map appears random. ' Recent study of the abundances and distributions of the elements in uranium deposits and in the altered sandstone that encloses the deposits in a typical mining district (Legin area, San Miguel County, Colo.) shows that the amount of each ele- Iment added to the deposits, except uranium and vanadium, could have come from the altered sand- stone, without the sandstone having had unusually high original concentrations of the elements. How- ever, the regional distributions of the elements in uranium deposits of the Salt Wash member, con- sidered together with the hydrologic and structural history of the Salt Wash and the occurrence of some elements in veins, indicate that sources external to the Salt Wash host rock contributed some elements, and that at least two periods of mineralization occurred. The broad features of the regional distribution of elements in uranium deposits of the Salt Wash mem- GEOLOGICAL SURVEY RESEARCH 1961 her of the Morrison formation might be explained by the hypothesis outlined below. After burial of the Salt Wash member by the Brushy Basin member of the Morrison formation, ground water within the Salt Wash was confined and discharge probably minor. As a result, the ground water became nearly stagnant. It is postu- lated that precipitation of iron and minute amounts of other elements near carbonaceous material caused concentration gradients to be established within the stagnant ground water, and diffusion of iron and other elements toward the carbonaceous material began in response to the gradients. In the chemical environments likely to occur near carbonaceous ma- terial (Hostetler and Garrels, written communica- tion), the solubility of iron is highly sensitive to Eh and pH differences. This implies that the concentra- tion gradients of iron in solution were steep and that diffusion of iron may have been relatively rapid. Boundaries or interfaces between nearly stagnant solutions near and more distant from carbonaceous material were established owing to contrasting chemistry of the solutions, and could have remained relatively stable because of the nearly stagnant ground-water conditions. The interfaces were marked by the precipitation of pyrite and other sulfides; these formed roll—type structures. Iron and most other Group I elements that accumulated during this early stage of mineralization could have been derived from devitrification of tuffaceous material in the sandstone Within a few hundred feet of the de- posits. Deposits on the western part of the Plateau may be richer in these elements because the sand- stone there contained more tuff. At a later stage in the history of the deposits, structural deformation of the Salt Wash and asso- ciated rocks occurred on a regional scale in the Salt Valley region of western Colorado and eastern Utah. Numerous northwest-trending faults were developed on the flanks and crests of the anticlines, and the rocks of Early Cretaceous and older age were in- truded by laccoliths which are now partially exposed in the La Sal Mountains. The structural deforma- tion opened channels of recharge and discharge and activated ground-water flow within the Salt Wash member. Solutions bearing copper, silver, lead, and zinc (Fischer, 1936, p. 575) deposited these elements as sulfides in several formations along faults in the salt anticline region, and may have enriched the ground waters in these elements. Enrichment of ground water in the Salt Wash member by addition of solutions from an external source may account for the relative high copper content of sandstones SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 from the Salt Wash in this region, and may also explain why the uranium ores from the Salt Wash member in the salt anticline region contain more copper, silver, lead, and zinc than ores from the Salt Wash in other areas. ‘ Inasmuch as uranium and vanadium could not have been derived from altered sandstone adjacent to the deposits, they must have been derived from snore distant sources, and the transporting mech- anism was probably flowing solutions, rather than diffusion. Uranium and vanadium may have been deposited during the second stage of mineralization, along with copper, lead, silver, and some of the zinc, but this is uncertain. According to this hypothesis, the forms of the deposits were established by the first stage of mineralization, when pyrite and 0“- :r sulfides of Group I elements accumulated in roll- structures. Uranium may have been precipitated from solution by the reduction of hexavalent uranium in a complex carbonate ion by the earlier formed 124. ‘3, B—291 pyrite, thereby preserving the roll-structures as uraniferous ore bodies. In the laboratory, uraninite has been precipitated from aqueous solutions by the reduction of uranium with pyrite (Vickers, 1956). This mechanism explains the common abundance of limonfife adjacent to uraniferous ore bodies. REFERENCES Fischer, R. P., 1936, Peculiar hydrothermal copper-bearing veins of the northeastern Colorado Plateau: Econ. Geol- ogy, V. 31, no. 6, p. 571~599. Shoemaker, E. M., Miesch, A. T., Newman, W. L., and Riley, L. B., 1959, Elemental composition of the sandstone-type deposits, in Geochemistry and mineralogy of the Colorado Plateau uranium ores, compiled by R. M. Garrels and E. S. Larsen, 3d: U.S. Geol. Survey Prof. Paper 320, p. 25—54. Vickers, R. C., 1956, Syntheses of pitchblende, in Geologic investigations of radioactive deposits—Semiannual prog- ress report, June 1 to November 30, 1956: U.S. Geol. Survey TEI—640, p. 305, issued by U.S. Atomic Energy Comm. Tech. Inf. Service, Oak Ridge, Tenn., p. 305. 5% HYDROGEOCHEMICAL ANOMALIES, FOURMILE CANYON, EUREKA COUNTY, NEVADA By R. L. ERICKSON and A. P. MARRANZINO, Denver, Colo. Results of analyses of spring waters in Fourmile Canyon, Cortez quadrangle, Eureka County, Nev., show marked metal anomalies in a little-prospected area. Spring waters near the head of the canyon are acid sulfate waters that contain as much as 300 ppb (parts per billion) heavy metals (Zn, Cu, Pb); waters near the mouth of the canyon are slightly alkaline bicarbonate-sulfate waters that contain as much as 60 ppb molybdenum. The springs occur in siliceous clastic rocks of Silurian age in the upper plate of the Roberts Moun- tains thrust fault (James Gilluly, oral communica- tion, 1960). A quartz monzonite mass intrudes the clastic rocks near the head of the canyon and the strongest base-metal anomaly occurs in springs near the contact of quartz monzonite and clastics (fig. 124.1). Sufficient water issues from these springs to maintain permanent flow a few hundred yards down- stream. Between sample localities W—52 and W—52B the pH and heavy metal content of the water were determined at 100-foot intervals; the pH ranges from 4 to 5, sulfate is the principal anion, and the heavy metal content determined with dithizone ranges from 100 to 300 ppb (background in Fourmile Canyon is less than 20 ppb). Spectrographic analyses of the residue after evaporation of the waters show that the chief heavy metal is zinc, but that manganese, nickel, copper, and cobalt are also anomalously high. Coatings of red iron oxide on stream-bottom sedi- ments contain as much as 1,500 ppm arsenic and 20 ppm molybdenum. The source of the acid, high sulfate, and high base metal content of the springs and also the high arsenic content of the iron-oxide precipitate on the stream bottom probably is a con- cealed oxidizing sulfide deposit. Bicarbonate-sulfate spring water contains 60 ppb molybdenum at locality W—50 and 15 to 20 ppb molybdenum in adjacent springs (background in Fourmile Canyon is about 2 ppb). There are no rock exposures in the vicinity of W—50 and the source of the molybdenum is unknown. B—292 GEOLOGICAL SURVEY RESEARCH 1961 \-. \ “ -60 _.‘, \«. _i/ J A ‘91-70 '-- ~ P "’ Mo-ZO \ HM—ZO .\ -\\ ‘\ Rocks of Silurian age A“ w-5o ‘. 0- \ "'\_ HM-30 /.--/ "\ _<--' Y \i ‘\ \ / \ l .\ — "-“»\.4 ’ / pH-7.9 _./' {Mo—15 \ / lHM-IOO \ \ / \-,? wan ../\ =.W-53 ”-1158 ’_.~..-/"pH-7.4 —..,/' '- _ ,./ ‘°‘/ Mo-Z ; fatal ../ 9:;ng "mo : ’/ HM-<20 \K. HM-40 . ‘/-—’ w \. is \ " pH-6.6 ‘ L 4 ' —523"‘°-'<2 < p 7 v ' \ HM-lO/g ‘7 ~. , , . p — . 'W—\52A< Mo—(Z t°w_5g HM-240 " pH—4.6 w—52f’l Mo-<2 pH 6,2}=\ HM-300 HM 20,) 1M|LE l Geology modified from unpublished geologic map of Cortez quadrangle by James Gilluly and Harold Masursky FIGURE 124.1.—Map showing sample locality (W), pH, molyb- denum (Mo) and heavy metal (HM) content, in parts per billion, of some spring waters in Fourmile Canyon, Eu- reka County, Nev. ’X SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 125. B—293 GRANTSITE, A NEW HYDRATED SODIUM CALCIUM VANADYL VANADATE FROM NEW MEXICO AND COLORADO—A PRELIMINARY DESCRIPTION By A. D. WEEKS, M. L. LINDBERG, and ROBERT MEYROWITZ, Washington, D. C. Grantsite, anew hydrated sodium calcium vanadyl l and absorption. The blades or fibers are “length vanadate, is a dark clive-green to greenish-black mineral which occurs in fibrous aggregates that coat fractures or form thin seams in sandstone or lime- stone in vanadiferous uranium ores of the Colorado Plateau. It very rarely forms microscopic bladed single crystals. It is soft and smears easily when rubbed—a characteristic of most of the vanadyl vanadate minerals or “corvusite” group to which it belongs. A small amount of this mineral was first found in an ore sample collected in 1952 by T. W. Stern from an early prospect of the F—33 mine (Anaconda Company, Sec. 33, T. 12 N., R. 9 W.) in Valencia County, near the town of Grants, N. Mex. It comes from the Todilto limestone of Late Jurassic age. Grantsite was also collected in 1954 by A. D. Weeks, R. B. Thompson, and R. F. Marvin from the La Salle Mining Company’s shaft on Club Mesa, Montrose County, Colo. and in 1956 by A. D. Weeks and A. H. Truesdell from the Golden Cycle mine on Atkinson Mesa, near Uravan in Montrose County, Colo. The two Colorado samples are from the Salt Wash sand- stone member of the Morrison formation of Late Jurassic age. In 1957 during a detailed study of the F-33 mine near Grants, N. Mex., Weeks and Trues- dell found much more material and observed the paragenesis and oxidation sequence, which will not be discussed here. Grantsite is monoclinic with the elongation of the fibers parallel to the b-axis. It usually forms aggre- gates of extremely fine fibers or narrow blades, simi- lar in habit to the hewettite group of vanadates which are also elongated parallel to the b-axis. Its luster is silky or pearly to subadamantine. The optical prop— erties cannot be determined accurately or completely because of its very fine grain size and high refraction slow.” The indices of refraction are a between 1.81 and 1.83, ,8 > 2.0, and y > 2.0. The orientation and pleochroism are X normal to the blade, green, Y parallel to the intermediate dimension of the blade, greenish brown, and Z = 1) parallel to the length of the blade, brown. The absorption is Z > Y > X. The mineral is biaxial negative. The strongest lines of the X-ray diffraction powder pattern for sample AW—43—56, Golden Cycle mine, with Cr-radiation, V-filter (K0.1 = 2.2897) are as follows in order of decreasing d-spacings in Ang- strom units and intensity given as strong S, medium strong MS, and medium M: 12.4 MS, 8.7 S, 4.34 M, 3.719 M, 3.607, MS, 3.008 MS, 2.866 M, 2.715 M, 2.275 M, and 2.240 M. A partially completed set of single-crystal precession and rotation patterns indi- cates grantsite is monoclinic: a = 17.54, b = 3.60, c = 12.45; 5 2 95°15’; unit cell volume = 781A”, The b-axis is the fiber axis; individual fibers are tabular parallel to (100). Chemical analyses have been completed on sample AW—47—54 from the La Salle mine, AW—43—56 from the Golden Cycle mine, and AW—20—57 from the F—33 mine. All are essentially hydrated sodium calcium vanadyl vanadates but the amount of cal- cium and V+4 varies slightly in the samples. The ratio of the oxides is close to 2NagO-CaO-VZOJ) 5V205-8H20. The gram-formula-weight as derived from the unit cell volume and the observed density of 2.94 gcm3 is 1383. This corresponds closely to the weight of the oxides as derived from the chemical analysis and equals 1400. ' The name grantsite is for the town of Grants, N. Mex., near which the mineral was discovered and later found more abundantly in partly oxidized vana- diferous uranium ore. ’X B—294 126. GEOLOGICAL SURVEY RESEARCH 1961 INSOLUBLE RESIDUES AND Ca :Mg RATIOS IN THE MADISON GROUP, LIVINGSTON, MONTANA By ALBERT E. ROBERTS, Denver, Colo. The Madison group is exposed prominently in the lower canyon of the Yellowstone River near Living- ston, Mont. It includes the Lodgepole limestone, which is partly Kinderhook and partly Osage in age, and the overlying Mission Canyon limestone, which is partly Osage and partly Meramec in age. Age assignments are similar, in part, to those suggested by Sloss and Moritz (1951, p. 2155) and Sando and Dutro (1960, p. 118). The Lodgepole is 575 feet thick; the Mission Canyon is subdivided into a lower member 330 feet thick, and an upper member 325 feet thick. Generally, the limestone in the Madison group is massive to thick bedded, finely to coarsely crystalline, light olive gray (5Y5/2)1, fossiliferous, oolitic, and 'contains less than 5 percent insoluble residues. The dolomite is generally medium to thin bedded, micro- crystalline, variable in color, but usually light olive gray (5Y6/ 1) to yellowish brown (10YR6/2), com- monly brecciated, and contains more than 5 per- cent insoluble residues. A few dolomite units are fossiliferous, but most of the fossils are in lime- stone units. Oolites occur only in massive limestone containing very little insoluble residues. The lith— ology of the formation is shown on figure 126.1. Chert is common throughout the carbonate se- quence in thin layers along bedding planes or, less commonly, in nodules or lenses. The thin layers have irregular shapes in cross section and they stand out in etched relief on weathered surfaces. The relative amounts of chert and insoluble residues in individual ‘ stratigraphic units have no apparent relation. Dolomite beds in the Madison group include some intraformational breccias and some local breccias caused by readjustment during folding. Laterally persistent breccia beds in the Mission Canyon lime- stone may be solution breccias resulting from re- moval of soluble minerals such as anhydrite or gyp- sum. Similar laterally continuous breccia beds in the Mission Canyon have been described by McMannis (1955, p. 1400) in the Bridger Range, and by Klep-_ per, Weeks, and Ruppel (1957, p. 19) in the Elkhorn Mountains. A bed 51/2 feet thick of limestone con- glomerate forms the base of the upper member of the Mission Canyon at Livingston. A similar con- 1Designation as shown on the Rock-Color Chart of the National Re- search Council, 1948. glomerate is found at the same stratigraphic horizon in the Gallatin Basin, Mont. (Laudon, 1948, p. 295; Andrichuk, 1955, p. 2179) and a breccia zone is found at this horizon in north-central Wyoming (Denson and Morrissey, 1952, p. 40) and in western Wyoming (Strickland, 1956, p. 54). Calcium-magnesium ratios and percentages of in- soluble residues are given on figure 126.1. The Lodge- pole limestone has relatively few dolomite or dolo- mitic limestone strata; the Mission Canyon has con- siderable dolomite and dolomitic limestone. The Ca :Mg molal ratio curve illustrates a cyclic alterna- tion of carbonate rocks of varying 03003—Mg003 composition. The cycles are imperfect or are not apparent in the lower part of the Lodgepole but be- come better defined in the Mission Canyon, and in the upper member of the Mission Canyon they are easily demonstrated. The intimate interlayering of dolomite and limestone, as well as the finer crystal- linity of the dolomites and a larger content of in- soluble residues in the dolomites relative to the lime- stones are systematic variations that seem most easily explained if most of the limestone and dolo- mite was deposited directly from sea water. Cyclic deposition of limestone and dolomite in Mississippian rocks is excellently illustrated by Laudon and Sever- son (1953, p. 509—512) in the Bridger Range, Mont., and cyclic deposits of this age at Logan, Mont., have been observed by G. D. Robinson (1961, oral commu— nication). The fossil assemblages in these rocks indi- cate normal marine benthonic faunas that probably lived in relatively shallow, well-aerated waters on extensive shelves or in epeiric seas (Dutro, Sando, and Yochelson, 1958, written communication). The percent-carbonate curve (fig. 126.1) shows, in general, an increase of insoluble residues in the dolomite compared to the limestone. Recent studies by Roy and others (1955), Fairbridge (1957), Dun- bar and Rodgers (1957), and Bisque and Lemish (1959) discuss or demonstrate this same relation for dolomites in general. Insoluble residues in the Madison group at Living- ston consist predominantly of clay minerals, fossil fragments, quartz, feldspar (mostly microcline), and chert, and lesser amounts of pyrite, magnetite, tour- maline, zircon, garnet, biotite, and sphene. The clay minerals, identified by X-ray diffraction, are illite, SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 Z _l 90", >- . S Egggég g MOLAL RATIO CaMg < 00- . E E w'gfig’i % Limestone Dolomitic : Calcitic ‘ E 2 wa8"; l5 limestone dolomite ' PERCENT CARBONATE r—%—~—fi FEET I 50 75 100 I 0’ —\I. (it. u .—<". Q) V E C 2 / 1’ °\ 5 C S i ‘9 / W O) O 5 j _?_ I I I]. .<", .<." .7 \. w ‘1’ ' ‘ o: g i a \- m c ; E gig O i / z (D "U 0 g ml; I o: 9‘5 ,/‘ a 5‘ 7 'i ? ‘3’. 1 ‘2 E1 . W l 1.9% l \ 3 58‘ i17764 PC 1 E‘ l — . i =1 1 300 \ 1 lgi mes-Po - 18‘ 2a; :0: 3‘ 1:5; 1‘ l E I l . l ,/ i l /\. 1 50 5 1 PERCENT CALClTE Section measured in section 35, T. 2 S., R. 9 E.. and sections 1 and 2, T. 3 8., R. 9 E. EXPLANATION W.“ W.“ w.” Limestone Dolomitic limestone Dolomite Silty dolomite Silty limestone Magnesian limestone Silty dolomitic limestone Calcitic dolomite Conglomeratic dolomite A '3 Chen Samples containing phosphate- . sulfate mineral FIGURE 126.1.—Stratigraphic section of the Madison group near Livingston, Mont. B—295 B—296 kaolinite, and mixed clays. Illite ranges from 60 to 100 percent of the total clay minerals and averages approximately 90 percent. A few insoluble residues contain as much as 30 percent kaolinite, but most contain 10 percent or less. About half the insoluble residues from the Mission Canyon limestone contain mixed clays (illite and montmorillonite), ranging from a trace to as much as 20 percent. Only‘one in- soluble residue from the Lodgepole limestone con- tained mixed clays. In the upper member of the Mission Canyon six insoluble residues contained an unidentified hydrous double salt (probably of the beudantite group) very similar to woodhousite [Ca A13 (P04) (S04) (OH,,)]. This mineral was found in the dolomites or calcitic dolomites that contained less than 15 percent insoluble residues. Samples con- taining this mineral generally were rich in kaolinite or mixed clays and poor in illite. Phosphate and sul- fate radicals in this mineral suggest incipient de- position of evaporites. The solution-breccia zones and presence of ‘this mineral are consistent with a tentative correlation of the upper member of the Mission Canyon limestone at Livingston with inter- bedded carbonates and evaporites that elsewhere in Montana make up the Charles formation. REFERENCES Andrichuk, J. M., 1955, Mississippian Madison group strati- graphy and sedimentation in Wyoming and southern Montana: Am. Assoc. Petroleum Geologists Bull., v. 39, no. 11, p. 2170-2210. Bisque, R. E., and Lemish, John, 1959, Insoluble residue— magnesium content relationship of carbonate rocks from 127. GEOLOGICAL SURVEY RESEARCH 1961 the Devonian Cedar Valley formation: Jour. Sed. Petrol- ogy, v. 29, no. 1, p. 73—76. Denson, M. E., Jr., and Morrissey, N. S., 1952, The Madison group (Mississippian) of the Big Horn and Wind River Basins, Wyoming, in Wyoming Geol. Assoc. Guidebook, 7th Ann. Field Conf., p. 37—43. Dunbar, C. 0., and Rodgers, John, 1957, Principles of strati- graphy: New York, John Wiley and Sons, Inc., 356 p. Fairbridge, R. W., 1957, The dolomite question, in Le Blanc and Breeding, eds., Regional aspects of carbonate deposi- tion—a symposium: Soc. Econ. Paleontologists and Min- eralogists Spec. Pub. no. 5, p. 125—178. Klepper, M. R., Weeks, R. A., and Ruppel, E. T., 1957, Geol- ogy of the southern Elkhorn Mountains, Jefferson and Broadwater Counties, Montana: U.S. Geol. Survey Prof. Paper 292, 82 p. Laudon, L. R., 1948, Osage—Meramec contact, in Weller, J. M., ed., Symposium on problems of Mississippian stratigraphy and correlation: Jour. Geology, V. 56, no. 4, p. 288—302. Laudon, L. R., and Severson, J. L., 1953, New crinoid fauna, Mississippian, Lodgepole formation, Montana: Jour. Paleontology, v. 27, no. 4, p. 505—536. McMannis, W. J., 1955, Geology of the Bridger Range, Mon- tana: Geol. Soc. America Bull., v. 66, no. 11, p. 1385—1430. Roy, C. J., Thomas, L. A., Weissmann, R. C., and Schneider, R. C., 1955, Geologic factors related to quality of lime- stone aggregates: Highway Research Board Proc., v. 34, p. 400—412. Sando, W. J., and Dutro, J. T., Jr., 1960, Stratigraphy and coral zonation of the Madison group and Brazer dolomite in northeastern Utah, western Wyoming, and south— western Montana, in Wyoming Geol. Assoc. Guidebook, 15th Ann. Field Conf., p. 117—126. 81055, L. L., and Moritz, C. A., 1951, Paleozoic stratigraphy of southwestern Montana: Am. Assoc. Petroleum Geologists Bull., v. 35, no. 10, p. 2135—2169. Strickland, J. W., 1956, Mississippian stratigraphy, western Wyoming, in Wyoming Geol. Assoc. Guidebook, 11th Ann. Field Conf., p. 51—57. 6? MANGANESE OXIDE MINERALS AT PHILIPSBURG, MONTANA By WILLIAM C. PRINZ, Washington, D. C. The Philipsburg district is underlain by sedimen- tary and metamorphic rocks of Precambrian and early Paleozoic age that have been intruded by a ~ granodiorite batholith of Tertiary age. The sedi- mentary rocks consist of limestone, dolomitic and calcitic marble, shale, and quartzite that have been folded into a broad north-plunging anticline (God- dard, 1940, pl. 26). Hydrothermal veins containing quartz, sphalerite, galena, silver- and copper-bearing sulfides, barite, and late rhodochrosite cut both the granodiorite and the sedimentary rocks. These veins strike west or northwest and have steep southerly dips or are vertical. Late hydrothermal rhodochro- site has partly replaced some favorable limestone and marble beds adjacent to some veins. In thin limestone or marble beds, the replacement deposits . SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 follow bedding closely and form tabular ore bodies. In massive or thick-bedded marble they tend to be irregular vertical pipes that swell in more favorable beds and pinch in less favorable ones. Sphalerite, some silver, and sparse galena accompany rhodo- chrosite in the primary replacement deposits in parts of the district. Oxidation of rhodochrosite by ground water has produced various manganese oxide minerals. The following have been identified by X-ray and micro- scopic techniques : - Todorokite ((Ca,Na,Mn“,K) (Mn1",Mn II,Mg)(;012 -3H20) until recently was considered rare as it had been observed only at its type locality in Japan, but in the last year it has been identified at numerous localities. At Philipsburg it is widely distributed in the oxidized replacement deposits where it forms aggregates of irregular or fibrous grains. It is com- monly pseudomorphous after carbonate minerals or in bands with cryptomelane, gamma-MnOg, or py- rolusite. ' Cryptomelane (KR..O,.;, R = Mn”,Mn1") was first identified in the Philipsburg oxide ore by Richmond and Fleischer (1942, table 1). It is probably one of the more abundant oxide minerals in the district, but to date I have done little chemical work on the mineral and some of the material that I have identi- fied as cryptomelane may be one of the other mem- bers of the psilomelane group. Cryptomelane and gamma-Mnog comprise the bulk of the material called “psilomelane” in hand specimen. Gamma-MnO2 is hard (about 6), anisotropic, and white with a faint cream tint in polished section. It gives X-ray patterns similar to those of synthetic gamma- and rho-Mn02 and is probably the same mineral described by Sorem and Cameron (1960) as Nsuta Mn02. It is in bands with cryptomelane and todorokite, forms pseudomorphs after carbonate minerals, and is in late veinlets that cut earlier formed manganese oxides. Pyrolusite (Mn02) is commonly a late mineral that lines vugs in quartz or earlier formed oxide min- erals. Some also formed with the other oxides and has a habit similar to theirs. Chalcophanite ((Mn”, Zn)Mn"'2O,-,-2H20) is com- monly late and fills vugs, but it is also in bands with cryptomelane, in tiny prisms in a fine-grained matrix of todorokite, and in stalactites with hetaerolite and todorokite. B—297 Hetaerolite (Znanog was found in only a few samples from oxidized veins where it is associated with chalcophanite. Manganite (Mn303'H30) is rare. In one place it formed early and is cut by later manganese oxide minerals; in another it was formed late and lines vugs in earlier formed oxides. Wad, the soft, dark brown to black earthy ma-' terial, was shown by X-ray analysis to consist of one or more of the following minerals: todorokite, cryp- tomelane, chalcophanite, pyrolusite, or goethite. Cryptomelane, todorokite, gamma-Mnog, and py- rolusite are the most abundant manganese oxide minerals at Philipsburg (probably in that order), chalcophanite is locally abundant, hetaerolite and manganite are rare. Todorokite is restricted to the oxidized replacement deposits, probably because of the availability of calcium in these deposits and its absence in the veins. The zinc-bearing manganese oxides, chalcophanite and hetaerolite, are found in or adjacent to oxidized veins or in oxidized replace- ment deposits only in areas where the primary rhodo- chrosite is accompanied by sphalerite. These two minerals may prove to be valuable guides to the exploration for deeper primary rhodochrosite de- posits that also contain sphalerite. The depth of oxidation ranges from as little as 100 feet in some impure limestone beds to more than 850 feet in massive coarse-grained marble where open cavities and water courses are common. Un— oxidized remnants of rhodochrosite are preserved within some oxidized ore bodies or below imper- meable beds. I agree with the suggestion of Pardee (1921, p. 155) that the formation of the manganese oxide minerals was accompanied by only limited migration and secondary concentration of manganese. REFERENCES Goddard, E. N., 1940, Manganese deposits at Philipsburg, Granite County, Montana: US. Geol. Survey Bull. 922—G, p. 157—204. Pardee, J.‘ T., 1921, Deposits of manganese ore in Montana, Utah, Oregon, and Washington: US. Geol. Survey Bull. 725—0, p. 141—177. Richmond, W. E., and Fleischer, M., 1942, Cryptomelane, a new name for the commonest of the “psilomelane” min- erals: Am. Mineralogist, v. 27, p. 607—610. Sorem, R. K., and Cameron, E. N., 1960, Manganese oxides and associated minerals of the Nsuta manganese deposits, Ghana, West Africa: Econ. Geology, V. 55, p. 278—310. 6% B—298 128. GEOLOGICAL SURVEY RESEARCH 1961 URANIUM AND RADIUM IN GROUND WATER FROM IGNEOUS TERRANES OF THE PACIFIC NORTHWEST By FRANKLIN B. BARKER and ROBERT C. SCOTT, Denver, Colo. Water samples from the igneous terranes of the Pacific Northwest were collected and analyzed for uranium and radium as part of a study of the geochemistry of radioelements. For this work these igneous terranes were divided into those developed on the Idaho batholith (silicic intrusive terrane), Columbia River basalt, Snake River basalt, and silicic-subsilicic volcanic rocks. The data on radium and uranium concentrations in water from each terrane were analyzed statistically so that character- istic parameters could be obtained and compared. The concentrations of uranium in water from each terrane except the Snake River basalt are in ex- cellent agreement with log-normal distributions. The samples from the Snake River basalt showed a . uranium-concentration distribution that was skewed to the left (lower concentration). The concentrations of radium in all of these terranes were so low that only small portions of the distribution curves were above the detection limit, 0.1 pc/ 1 (picocuries per liter; 1 pc = 10—12 curies), and could readily be examined. In all instances, however, these portions were found to agree with log-normal distributions; therefore, these distributions have been assumed to be valid for the entire range of concentrations. The statistical parameters applicable to the radium and uranium concentrations in water from the various terranes are given in table 1. The geometric means are those obtained from the assumed log-normal dis- tributions. No value is reported for the geometric mean of uranium Concentrations in water from the Snake River basalt because a log-normal distribution does not fit the data. TABLE 1,—Statistrical parameters relating to concentrations of uranium and radium in water from igneous terranes Uranium ug/lI Radium pc/l Number Terrane of Geo— ' Geo- samples Range Median metric Range Median metric ‘ mean mean Silicic-subsilicic me 5 ....... . 73 (0.1—10 0.2 0.3 <0.1—62 0.1 01 Idaho batholith. 41 <0.]—13 .1 .07 <0.1—6,0 < .1 .03 Snake River basalt ........ 82 <0.1—2.6 1.4 ......... <0.1—17 <.1 .03 Columbia River basalt ......... 30 <0.1-0.6 .1 .1 <0.l—]0 <.l <.01 1 Mil/l : micrograms per liter or (approximately) parts per billion. The relative abundances of uranium in igneous rocks are generally in the order: silicic extrusive > silicic intrusive > basic extrusive. The relative abundance of radium should roughly parallel the abundances of uranium. The concentrations of ura- nium in the water samples were in the order: Snake River basalt > silicic-subsilicic volcanic rocks > Columbia River basalt m Idaho batholith; the con- centrations of radium, on the basis of the estimated geometric means, were in the order: silicic-subsilicic volcanic rocks > Idaho batholith ~ Snake River basalt > Columbia River basalt. The apparent dis- order of concentrations of uranium in water with respect to the abundances of uranium in rocks has been attributed partly to climatological and topo- graphical factors for the Idaho batholith, and to man’s agricultural developments on the Snake River Plain. The Idaho batholith is a mountainous region that receives much more precipitation than the other terranes, with an annual average of more than 20 inches over the entire area, compared with less than 10 inches for most of the area underlain by the silicic-subsilicic volcanic rocks and the Snake River basalt (Visher, 1954). Except for joints and other fractures, the permeability and porosity of the rocks of the batholith are lower than those of the other terranes. Thus, as ground water moves more rapidly through the jointed granitic rocks it has only a limited degree of rock-water contact, and, hence, has less opportunity to dissolve mineral matter. The concentrations are further reduced by dilution with the relatively large quantities of recharge resulting from the high precipitation rates. The‘flushing ac- tion of the large volumes of flow also contributes to the low concentrations in that much of the readily soluble material has already been dissolved and car- ried out of the area. As might be expected on the basis of this reasoning, the concentrations of all dissolved matter tends to be lower than in water from the other terranes. Variations in composition of the rocks probably contribute also to the observed differences in uranium concentrations. The Snake River Plain, which includes most of the area of the Snake River basalt, has been de— veloped agriculturally in many areas, and both ground water and surface water are used exten- sively for irrigation. Irrigation water dissolves ad- SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 ditional mineral matter from the soil and is further concentrated by evapotranspiration during its use; the unconsumed water then returns to the ground- water reservoir as a more concentrated solution. Much of the water tributary to the Snake River Plain originates in the adjacent silicic volcanic rock terranes, thus the recharge to the Snake River basalt has uranium concentrations greater than would be expected to be derived from the basalt. Another fac- tor that, possibly, contributes uranium to solution is that small amounts of uranium are present in some commercial high-phosphate fertilizers. The skewness of the observed distribution could have arisen if a few of the samples were from low-uranium water, representing a normal basalt terrane, and if a larger number of samples were from sources af- fected by one or more of those factors leading to abnormal concentrations of uranium. The water samples from the Columbia River basalt probably are more representative of the normal uranium con- tent in ground water from basalt terranes. The concentrations of radium in water from the Idaho batholith are less than those in water from the silicic-subsilicic volcanic rock terrane in about the same ratio as the differences in uranium con- centrations. This phenomenon might be explained partly by the large differences in annual precipi- tation; however, variations in composition of the rocks may also contribute to the differences in concentrations. - The concentrations of radium in water from the Snake River basalt are higher than those from the 129. B—299 Columbia River basalt, but they are not so anomalous as the uranium concentrations in water from the Snake River basalt. Radium is subject to the same concentrating processes as uranium, but it has not been enriched in the water of the Snake River basalt to the same extent as uranium. The basalt under- lying the Snake River plain contains many inter- calated lacustrine and other sedimentary beds of elastic material. Clays in this sedimentary material may have adsorbed some of the radium by cation exchange, thus reducing its concentration. The ura- nium, which probably exists in solution as an anionic uranyl carbonate complex, is not adsorbed effectively by this mechanism. Removal of radium from solu- tion in this or some other manner would partly com- pensate for the factors tending to cause enrichment. The observations discussed in this report are not definitive; however, they do indicate some general trends regarding the concentrations of uranium and radium to be expected in water from igneous ter- ranes. More detailed examination of possible inter- relations, both among samples from individual ter- ranes and among parameters characteristic of the different terranes, may define better the roles of various geologic, hydrologic, and geochemical factors in controlling the occurrence of uranium and radium in water. REFERENCE Visher, S. S., 1954, Climatic atlas of the United States: Cam- bridge, Mass., Harvard Univ. Press, p. 197. 5? ‘\C‘/ J. t/\..‘;/ \ SBORGITE IN THE FURNACE CREEK AREA, CALIFORNIA By JAMES F. MCALLISTER, Menlo Park, Calif. Work done partly in cooperation with the California Division of Mines Sborgite (Na20-5B203-10H30), which Cipriani (1957) described as a new mineral from Larderello, Italy, has been found in a different environment in the Furnace Creek area, Death Valley region, Cali- fornia. The sborgite at Larderello is in fine-grained mixtures of borax and thenardite that encrust artifi- [ cial conduits for natural steam; samples were recov- ered from depths between 104 and 256 meters some I time after eruption of steam at 1800 to 200°C had ceased (Cipriani, 1957, p. 520). In contrast, sborgite in the Furnace Creek area is unrelated to steam vents l or thermal springs, but forms virtually at the surface 8—300 by common processes that redistribute constituents of borate minerals under the control of the present desert climate. At three separate places near the Twenty Mule Team Canyon road, sborgite has been found locally concentrated within a few centimeters of the surface of the ground in debris weathered from the underlying Furnace Creek formation. In the Widow No. 3 mine], 10 miles southeast of Twenty Mule Team Canyon, sborgite is a constituent of small stalactites on an ore chute near the surface. At two localities near the Twenty Mule Team Can- yon road, concentrations of sborgite are localized in surficial debris around weathering colemanite and priceite veins in altered fragmental basalt. The veins lie stratigraphically above a zone that contains commercial deposits of colemanite and ulexite. Re- lationships of other borate minerals in the varied assemblages associated with sborgite and derived from the same veins have been briefly described (Erd, McAllister, and Vlisidis, 1961). Sborgite, like sassolite or ginorite, generally is distributed farther from the decomposing vein, whereas meyer- hofi'erite, gowerite, and nobleite generally remain nearer the vein. No other hydrous sodium borate mineral has been identified in these assemblages, which contain minerals consisting of boric acid or a hydrous borate of calicum, sodium-calcium, cal- cium-magnesium, or magnesium. Concentrations of sborgite at the third locality are limited to a strip about a meter wide along the strike of tilted beds of saline, tufi'aceous siltstone and sandstone. Much of this sborgite is associated With halite and thenardite in a layer as much as 15 cm thick that lies on bedrock. Above the bottom layer, a conspicuous efl‘lorescence of thenardite, like that left by the dessication of mirabilite, makes an incoherent but more persistent layer about 8 cm thick, which in turn is covered by a thin crust of very fine—grained debris. The underlying siltstone and sandstone, in contrast to the basaltic rocks, do not contain veins of colemanite and priceite or other obvious accumulations of borate minerals. The source of the sborgite, thenardite, and halite seems to be minerals disseminated in the elastic rocks and secondarily encrusted on minor joint surfaces. Stalactites that contain sborgite were formed at the foot of an ore chute in the Widow No. 3 mine about 25 meters below the surface where storm water could seep down through colemanite ore in 1 Property of the United States Borax & Chemical Corp., Los Angeles, Calif., which owns also the other specified sites within the boundary of Death Valley National Monument. GEOLOGICAL SURVEY RESEARCH 1961 9‘ TABLE 1.—~Compm‘ison of X-ray diffraction data for sborgite from California and Italy [Only reflections having d-spacings between 10.0 and 2.000 A and having intensities greater than 1/2 are listed! Lardercllo, Italy; Furnace Creek, Synthetic sample 10; chart X4123 1 Na20'5B203'101120 sborgite, borax, and sborgite (Cipriani. 1957) thenardite (Clpriaui, 1957) d—spacing d—spaciug d‘spacing . A Intensity (A) Intensity? A) Intensity2 8 59 2 8,62 2 8 . 58 2 8 19 2 8.22 2 8.21 2 ...................................... 7 . 79 1 ...................................... 7. 14 2 6 86 2 6.88 4 6.84 2 6 24 2 6.24 1 6.23 2 6 11 1 6.12 1 ................... ...................................... 5.97 1 ...................................... 5.69 3 ...................................... 5,37 1 ...................................... 5. 15 l 5. 1 1 2 5. 10 1 5. l 1 1 4.80 l 4.81 1 4.84 5 4.60 10 4.60 10 4.59 10 4.35 2 4,35 2 4.34 2 4.29 t 4 . 29 3 4.28 3 4, 11 2 4. 1 1 l 4. 09 1 ...................................... 3 . 93 2 ...................................... 3 . 83 2 3.74 5 1.74 2 3.73 4 3.56 5 l. 56 4 3.55 3 3,52 3 3.54 4 3.52 4 ...................................... 3.44 1 3 . 33 1 3 . 35 2 3 . 34 1 3,30 8 3.30 8 3.29 8 3 . 20 7 3 .20 8 ................... 3 . 18 5 ................... 3 . 18 7 3.12 1 5 13 1 3.13 2 ...................................... 3.07 5 3.04 2 3.04 2 3.04 3 2.95 2 2.95 1 2.94 2 2.93 3 2.93 2 2.92 3 2.86 2 2.865 2 2.827 4 ...................................... 2. 784 5 ................... 2 676 2 2.669 1 2.64 l ................... 2.646 3 2.57 2 2.572 4 2.564 5 2.40 1 2.409 1 2.406 1 2.35 1 2.350 1 ................... ...................................... 2.329 2 ................... 2.274 1 2.25 1 2.253 1 2.253 1 2.21 2.215 2 2.210 2 2. 17 l 2 . 177 1 ................... ................... 2. 169 l 2. 173 1 2.14 1 2.139 1 2.140 2 2.09 | 2.090 1 2.085 1 ...................................... 2.073 1 ...................................... 2.064 1 ...................................... 2.037 1 ................... 2.025 2 1 CuK 01 (Ni filter), )\ : 1.5418A 3 Intensities recorded by Cipriani have been rounded to the nearest whole number, maximum 10. the chute. Several nearby openings to the surface on the same level as the stalactites provided good circulation of desert air for evaporating the saline solution that deposited a highly soluble fine-grained mixture of thenardite, sborgite, and halite. These SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 minerals go into solution readily in water at 26°C. The largest stalactite is 20 mm in diameter; a slender one, ovate in section, is from 5 to 10 mm in diameter. The stalactites consist of a shell of sborgite, thenardite, and some halite, from a frac- tion of a millimeter to about 3 mm thick, that en- closes a more friable mixture of thenardite, halite, and an unidentified borate. The rate of growth is not known, but the age is no more than 35 years, which is the length of time since mining stopped in the mid-1920’s. The sborgite occurs in sugary-textured crystal ag— gregates and mesh-Work in loosely coherent weath- ered materials. Anhedral to euhedral crystals are colorless and generally 0.05 to 0.2 mm in diameter, but some are nearly 1 mm. The following combina- tion of optical properties distinguishes sborgite from B-301 other known borate minerals: biaxial positive, mod— erately small optic angle, lowest measured index of refraction 1.432 : 0.002, and highest measured in- dex of refraction 1.488 i 0.003. R. C. Erd (written communication, 1958) has provided X-ray powder diffraction data given on table 1, and pointed out the close similarity to data for sborgite and syn- thetic NagO-5B203-10H20 as reported by Cipriani (1957, table 1). REFERENCES Cipriani, Curzio, 1957, Un nuovo minerale fra i prodotti boriferi di Larderello: Accad. naz. Lincei, Atti, classe sci. fis., mat. e nat., Rend., v. 22, p. 519—525. Erd, R. C., McAllister, J. F., and Vlisidis, A. C., 1961, No- bleite, another new hydrous calcium borate from the Death Valley region, California: Am. Mineralogist, v. 46, p. 560—571. 5% GEOLOGY AND HYDROLOGY APPLIED T0 ENGINEERING AND PUBLIC HEALTH 130. ECONOMIC SIGNIFICANCE OF A BURIED BEDROCK BENCH BENEATH THE MISSOURI RIVER FLOOD PLAIN NEAR COUNCIL BLUFFS, IOWA By ROBERT D. MILLER, Denver, Colo. Industrial plants are beginning to dot the flood plain of the Missouri River in ever-increasing num- bers since the completion of several flood-control dams along the Missouri River north of Omaha, Nebr. and Council Bluffs, Iowa. Availability of large tracts of level land, ample cheap water for industrial uses, and access to transportation are major factors in building on the flood plain. Absence of bedrock near the surface of the flood plain can, at places, require costly types of foundation construction. Bedrock configuration was studied as part of an investigation of the geology of the Omaha-Council Bluffs area. In most places bedrock is more than 100 feet below the flood plain. Southeast of Council Bluffs, however, a well-defined bedrock bench lies within 100 feet of the surface. The northern edge of the bench is about 3 miles southeast of Council Bluffs, about 11/; miles east of Lake Manawa, and about 1 mile east of the channel of the Missouri River (fig. 130.1). The bench underlies the southern part of sec. 20, and all of sec. 29 and 32, T. 74 N., R. 43 W., and sec. 5 and part of sec. 8, T. 73 N., R. 43 W. This bench is more than 3 miles long and 1 mile wide, is 80 to 90 feet below the flood plain, and has a nearly level surface. On the west the bench slopes gradually to depths of about 130 and 141 feet. The bedrock surface east of the bench proper is lower——more than 95 feet below the surface—which may indicate the presence of an old channel. The channel (?) may cross the northern part of sec. 20, T. 74 N., R. 43 W., but this is not definitely estab- lished. Bedrock is only 80 feet below the surface in the southeastern part of sec. 17, T. 74 N., R. 43 W.; bedrock at this depth suggests that there may be a northern remnant, or perhaps an extension, of the bedrock bench. Bedrock in the northern part of sec. 17, T. 74 N., R. 43 W. is more than 95 feet below the surface of the flood plain. B—302 GEOLOGICAL SURVEY RESEARCH 1961 ; 3’ EXPLANATION V m V/ t: :2 ilIHI///H\\\\i| V T. 75 N_ . Edge of flood plain / T. 74 N. o 90 fl ' m Depth and altitude of bedrock Upper figure, depth to bedrock; Lower figure, altitude of bedrock DUN CIL LU FFS ‘\”NW\ :11 O Lake Manawa RIGURE 130.1.—Map showing location of area underlain by bedrock bench near Council Bluffs, Iowa. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 The bedrock bench consists of limestone of Penn- sylvanian age that would provide a stable foundation for piles. Water-saturated alluvium overlies the bench and consists of fine, medium, and coarse sand, as well as layers of fine to medium gravel; no con- solidated layer intervenes between the bedrock bench and the ground surface. Access to the bench area 131. B—303 is provided by US. Highway 275, Iowa State Road 370, and the Chicago, Burlington, and Quincy Rail- road. * Suitable foundation conditions, good accessibility into the area, and ample water from the underlying alluvium indicate this area to be a potential indus- trial site. 6% RELATION OF SUPPORTS T0 GEOLOGY IN THE HAROLD D. ROBERTS TUNNEL, COLORADO By E. E. WAHLSTROM, L. A. WARNER, and C. S. ROBINSON, University of Colorado, Boulder, Colo., and Denver, Colo. Geologic conditions played an important part in the location and engineering of the Harold D. Roberts Tunnel, which extends for 23.3 miles from near Dillon to near Grant, Colo. (fig. 131.1). Among the engineering problems directly due to the geologic conditions was the use of supports during construc- tion of the tunnel. The purpose of the tunnel, which holed through in February 1960, is to bring water from the Blue River on the western side of the Continental Divide to the Platte River on the eastern side where it will be utilized as part of the water supply of Denver and environs. Construction was by the Blue River Constructors, Inc., under the supervision of Tipton and Kalmbach, Inc., for the Board of Water Com- missioners of the City and County of Denver. The regional geology in the vicinity of the tunnel has been described by T. S. Lovering (1935). Geo- logic investigations from 1943 to 1960 (prior to and during construction of the tunnel) were made by E. E. Wahlstrom assisted by L. A. Warner and V. Q. Hornback. In 1960 the US Geological Survey established a project to compile and publish the geology as related to the engineering. This article is a preliminary report of that project. GENERAL GEOLOGY The geology of the Roberts Tunnel, as it affects engineering problems, can be divided into five sec- tions: (a) a section of sedimentary rocks between the west portal and the Williams Range thrust, (b) the Williams Range thrust plate, (c) the sedimentary rocks between the Williams Range thrust and the Montezuma stock, (d) the Montezuma quartz mon- zonite stock, and (e) the Precambrian rocks between the Montezuma stock and the east portal. Figure PARK COUNTY g I Lead'ville I § 1 ___ ,, \‘ / I . g N \ ‘ | J (éolorado {—1 A I . prmgs a l l... _ — i l *4 -—‘-—-'*- l 1,. L. _ _ - _l o 5 10 30 MILES L, ,l,__ _J__ —-J FIGURE 131.1.—Index map showing location of the Harold D. Roberts Tunnel. GEOLOGICAL SURVEY RESEARCH 1961 8—304 .3559 £quva .9 303m 23 :msoufi cowuowm umwfloww vwszwhwcwwl.m.fima 559% $250 we 3:300 ucm 35 ,micofieEEoo 855 B Emom 9: B (smegma 5% 3:935 xomnEoI .5530 new 5525 < ._ .Eozmzfls m m E ,2: somnE‘mx Em :03; L8 $835 32: 89; $0.80 ththJO DZ< .wwEZO Fwiow Z<_mm=>_<0mmn_ N X mfixow :_ _ . . _‘ . _ Hum: 0006 H. OOO_OH 000m 0 mk.N._.mucwm$Em . w a $ Jooog m :9? mmwou< Etc H >> w. 53$: 52%. 225.22, mtmonma iaimnmx T w Joooi a P a wc< . 0. mm: :6 w W _ < a . _ 10003 M 7 1 ‘ boo? _ _ _ _ _ fl _ fi 00 + 000 00 + own 00 + com 00 + o? 00 + oov 00+ 0mm 00 + 00m 00 + 0mm 00 + cow 8 + 05 00 + 02 00 + 8 00 + 0 >> mcozflm mcconmcm SHORT PAPERS IN THE GEOLOGIC AND 131.2 is a geologic section through the tunnel show- ing the distribution of the principal rock types. The shale, sandstone, and limestone of Mesozoic age between the west portal and the Williams Range thrust have been extensively folded and faulted. The Williams Range thrust plate is brecciated Precam- brian rock of uncertain original composition that was silicified and later extensively faulted. The metasedimentary rock east of the Williams Range thrust plate probably is equivalent to some part of the section west of the thrust plate, but it has been baked to a black brittle hornfels by the intrusion of the Montezuma stock. The Montezuma stock con- sists of fine- to medium-grained locally porphyritic biotite quartz monzonite, which probably was in- truded during the Laramide orogeny. The Precam- brian schist, gneiss, quartzite, and lime-silicate rocks between the Montezuma stock and the east portal are complexly interlayered and injected with large and small bodies of granite, granodiorite, pegmatite, and aplite. The rock of one of the larger plutons resembles the Boulder Creek granite (Lovering and Goddard, 1950, p. 25—27). Near the east portal is granitic rock, containing many bodies of schist and gneiss, similar to the Silver Plume granite (Lovering and Goddard, 1950, p. 28). SUPPORTS IN RELATION TO GEOLOGY The geologic factors that influenced the use of supports are layering in the rock, spalling and pop- ping rock, faults and joints, and squeezing and swell- ing rock. Table 1 summarizes the relation between supports and geology. ~ The supports used are 6- and 8-inch steel horse- shoe-shaped H ribs supported on wooden footblocks, With struts across the tunnel invert where necessary. Tie rods were used between ribs, and wooden lagging and wedges were placed above and on the sides of the ribs as required. The steel supports will be left in the tunnel as part of the reenforcing for the concrete lining. LAYERING IN ROCK Two types of layering contributed to the need for supports—stratification in the sedimentary rocks and layering in the schist and gneiss. The sedimentary rocks west of the Williams Range thrust (fig. 131.2) dip northeast at angles ranging from a few degrees to 30°. Consequently, the beds, especially in the shaly rocks, were flat enough in the tunnel arch to tend to break away from bedding planes if unsupported. Sets on 5-foot centers gen— HYDROLOGIC SCIENCES, ARTICLES 1-146 B-305 TABLE 1.—S'mnma7‘y of relation of tunnel supports to geology Average Section Percent spacing (stations) supported of sets Remarks (in feet) 9+46 (west portal) . . to 43+14 ............ 75.5 4.9 Mesozmc sedimentary rocks. Unsup- ported section in quartzite of Dakota group only. 43+14 to 180+20 ...... 100 3.9 Mesozoic sedimentary rocks below Williams Range thrust. Mostly shales, limy shales, and sandy shales. _ 180+20 to 291+50 ..... 100 2.5 Highly fractured and altered Precambrian schist, gneiss, and aplite in plate above Williams Range thrust. 291+50 to 339+75 ..... 100 4 2 Baked shale below Williams Range thrust. 339+75 to 3474—50 ..... 60.9 5 0 Mixed quartz monzonite and baked shale in border zone of Montezuma stock. 3474—50 to 625+00 ..... 88.0 4 .7 Quartz monzonite of Montezuma stock. 625+00 to 636+85 ..... 58.6 5.0 Quartzkite roof pendant in Montezuma stoc . 636+85 to 686+50 ..... 72 .4 5 0 Quartz monzonite of Montezuma stock. . 686+50 to 886+20 ..... 69.9 4 5 Precambrian schist, gneiss, and ‘quartzite with minor aplite, pegmatite, and granite. . ‘ 886+20 to 977+00 ..... 52.3 5.1 Boulder Creek(?) granite (granodiorite) with minor inclusions of metamorphic rocks. _ ‘ 977+00 to 1084+00... . 48.9 4.8 Precambrian schist and gneiss with minor aplite, pegmatite, and granite. 1084+00 to 1187+50. .. 24.0 4.8 Silver Plume(?) granite with numerous inclusions of schist, gneiss, and quartzite. 1187+50 to 1238+58 ‘ ‘ _ .. (east portal) ......... 7.3 4.5 Precambrian schist, gneiss, and lime sili- cates injected by granite and pegmatite. erally proved adequate to prevent detachment of slabs. The only section of sedimentary rock west of the Williams Range thrust that did not require sup—‘ port was massive quartzite of the Dakota group near the west portal. The stratification of the meta- sedimentary rock east of the Williams Range thrust was largely obliterated and therefore little support was needed. The layering in the schist and gneiss between the Montezuma stock and the east portal is commonly contorted, and the attitude of this layering in rela- tion to the bearing of the tunnel determined to a large extent whether or not supports were needed. Where the layering dips steeply, few or no supports were required, but where the layering is flat, sup- ports were required, usually on 5- or 6-foot centers. The schist and gneiss in the Williams Range thrust plate were silicified so layering in these rocks was not a factor in the need for support. SPALLING AND POPPING ROCK Spalling and popping rock, although not a serious problem, was encountered chiefly in that part of the tunnel extending southeast from station 595 + 00 in the Montezuma stock into the Precambrian rock at about station 965 + 00 (fig. 131.2). The thickness of cover in this portion of the tunnel ranges from about 1,500 to 4,500 feet. Spalling in parts of the tunnel continued for several hours after the rock was exposed and supports were used to enable safe advance of the heading. B—306 The spalling or popping rock generally was fresh, brittle, competent rock, such as granite or quartz monzonite, or unaltered schist or gneiss in flat layers. Some of the popping and spalling sections were be- tween less competent rock, or were bounded by faulted or fractured rock masses. The popping and spalling are attributed to the tendency of some of the rocks to establish a more stable arch; to the release of asymmetric stresses in rigid rock masses subjected to unequal loading by incompetent, plas- tically behaving, surrounding rock masses; and, pos- sibly, to residual stresses in rigid rock masses. FAULTS AND JOINTS The west portion of the tunnel, from the portal eastward to the west contact of the Montezuma stock, exposed jointed rock and numerous faults (fig. 131.2), including the Williams Range thrust. Faults in the Montezuma stock are not extensive, but locally they contributed to the development of sev- eral intersecting joint systems. Southeast of the Montezuma stock, faults of large displacement are uncommon, but locally many small faults and com- plex joint systems are present. The faults causing the most difficulty in the tun- neling operation were flat lying, contained consid- erable thicknesses of wet gouge, or were accom- panied by hydrothermally altered zones. Especially bad tunneling conditions prevailed where these con— 132. GEOLOGICAL SURVEY RESEARCH 1961 ditions combined. Closely spaced joints, or closely spaced faults and joints, generally produced blocks that required support. Joints, particularly in the Montezuma stock, also localized hydrothermal al- teration, which produced incompetent rock. SQUEEZING AND SWELLING ROCK Squeezing and swelling rock, which generally oc- curs in areas of extensive faulting and fracturing, caused considerable difficulty in several sections of the tunnel. Many faults, such as the Williams Range thrust, contain gouge that, Where saturated with water, created heavy loads on the tunnel supports. Some of the faults, especially in the plate over the Williams Range thrust and in the Montezuma stock, were channelways for montmorillonitic alteration, which resulted in slow swelling of the rock on ex- posure to moisture. This swelling tendency re- quired installation of considerable additional sup- port and realinement of tunnel supports in several sections of the tunnel behind the headings. REFERENCES Lovering, T. S., 1935, Geology and ore deposits of the Monte- zuma quadrangle, Colorado: US. Geol. Survey Prof. Paper 178, 119 p. Lovering, T. S., and Goddard, E. N., 1950, Geology and ore deposits of the Front Range, Colorado: US. Geol. Survey Prof. Paper 223, 319 p. ’X LANDSLIDES ALONG THE UINTA FAULT EAST OF FLAMING GORGE, UTAH By WALLACE R. HANSEN, Denver, Colo. Several factors in combination have produced abundant landslides along the Uinta fault east of Flaming Gorge, Utah, in the Antelope Flat-Clay Basin area. The Uinta fault is a large south-dipping high-angle thrust that trends east-northeast from the vicinity of Flaming Gorge toward and beyond the Utah-Colorado State line. Precambrian rocks form the hanging wall; Mississippian to Tertiary rocks form the footwall. Drag has steepened and overturned the bedding as much as a mile or more from the fault trace, especially in the footwall. Landslides are common along or near the Uinta fault on north-facing slopes of relatively high re- lief; examples are on the northeast slope of Boars Tusk, near the east end of Dutch John Mountain, and along the north slopes of Goslin Mountain, Moun- tain Home, and Bender Mountain (fig. 132.1). Slides in these areas range from small discrete slump blocks a few yards across to large complex masses of jumbled earth and rock covering hundreds of acres. Most of them appear to be relatively inactive or stabilized at the present time, although some show SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 B—307 109.30, 109 :15' ______ WYOMLNE 419 ANTELOPE FLAT llllllllllHIll/Iln “Hm“.Hunuu-H 'n , C \\\\“““.‘J‘ohn Mounw‘ .\ . . ' a '1”, Goslln Mountaln Humnnmlmu El; 9 a,” 3 a Mountain Home SI 3 : /, oDutch John s '8 :5 1"”Hm...un\““'”“Hum“ / I EFLAMING GORGE‘C‘ ”Wm”, 7,, DAMS/TE ”lHHHHuHHH/,m I I l40°52'30” 10 MILES l FIGURE 132.1.—Index map of Flaming Gorge area. evidence of recent movement such as headward scarplets and disarranged vegetation. Some older slides are much dissected and evidently have ceased moving. Locally, large boulders of resistant rock far removed from their source formations are all that remain of ancient slides. Landslides are most common where competent rocks, such as the Precambrian Uinta Mountain S Precambrian quartzite FIGURE 132.2.—Factors leading to slope failure along trace of Uinta fault (1) competent quartzite overlies incompetent steeply dipping shale; (2) oversteepened slope caused by difl’erential erosion causes potential instability; (3) northerly exposure minimizes insolation, resulting in (4) rank growth of vegetation and (5) rapid infiltration of moisture, which promotes sliding. group or the Red Creek quartzite, have overridden incompetent rocks, such as the Cretaceous Hilliard shale (fig. 132.2). At such localities differential ero- sion along the fault trace has locally produced high, steep north-sloping faultline scarps that are topo- graphically unstable. Most important, the north- erly exposure of slopes minimizes insolation and promotes a rank growth of vegetation, which en- courages and is encouraged by infiltration of mois- ture from rainfall and snowmelt. The larger amount of water in the north-facing slopes is a major factor in causing slides. Saturated conditions on the slopes along the Uinta fault are indicated by many small springs. Most of these springs are mere seeps, but some of them, such as Ford Spring, Edith Aspden Spring, and Fighting Spring, 11, 15, and 25 miles, respectively, east of Flaming Gorge, yield several gallons of water per minute. Virtually all landslides in the Flaming Gorge area are on northward-facing slopes—a few rockfalls ex- cepted. Otherwise similar, southward-facing slopes are stable and lack landslides. In the Mesaverde for- mation, for example, where south-facing cliffs of competent sandstone overlie steep slopes of incom- petent Hilliard shale, intense direct insolation sta- bilizes the slopes by drying the shale, inhibiting the growth of vegetation, and promoting rapid runoff. ’X‘ B——308 GEOLOGICAL SURVEY RESEARCH 1961 EXPLORATION AND MAPPING TECHNIQUES 133. GEOCHEMICAL PROSPECTING FOR COPPER DEPOSITS HIDDEN BENEATH ALLUVIUM IN THE PIMA DISTRICT, ARIZONA By LYMAN C. HUFF and A. P. That important mineral deposits lie hidden be- neath alluvium in the Basin and Range Province was convincingly demonstrated in 1951 by the dis- covery of the Pima copper deposit near Tucson, Ariz. Since this discovery other important ore deposits have been found hidden beneath alluvium in the Pima district and exploration activity has markedly in- creased throughout the Great Basin where many potential host rocks are covered by only a thin alluvial cover. The studies described here were made to determine what chemical techniques can be of use in this exploration. GEOLOGIC SETTING The Pima mining district is in Pima County about 15 miles southwest of Tucson, Ariz., in the north- eastern foothills of the Sierrita Mountains—a low, maturely dissected range bounded on all sides by an extensive alluvium-covered pediment. The ore deposits are on the northeast margin of a large batholithic intrusion of granodiorite of Lara- mide age which forms the core of the Sierrita Moun- tains. Near these deposits the marginal zone con~ sists of sedimentary rocks of Paleozoic and Mesozoic age that are metamorphosed, folded, complexly faulted, and intruded by various kinds of igneous rocks among which are small bodies of quartz mon- zonite porphyry believed to be genetically related to the ore deposits (Cooper, 1960, p. 74). The Pima ore deposit was found beneath about 200 feet of alluvium by exploratory drilling following magnetic surveys and geologic study (Heinrichs and Thur- mond, 1956). The ore of this mine and that of the nearby Banner and Mission deposits consists of dis- seminated chalcopyrite and molybdenite in metasedi- ments and hydrothermally altered porphyry. It is similar in many respects to other deposits of por- phyry copper type of the Southwest except for its alluvial cover. SAMPLING AND ANALYSIS To indicate whether geochemical anomalies were present in the vicinity of these concealed ore bodies, samples were collected of surface soil, surface allu- MARRANZINO, Denver, Colo. vium, a carbonate-cemented zone at the base of the alluvium, ground water, and vegetation. The soil and the alluvium samples were sieved to minus 80 mesh when collected and the fines were used for analysis. The carbonate-cemented alluvium required crushing before sieving. Samples of these materials were obtained from the land surface, the open pit of the Pima mine, drill holes, and wells. The deeper zones of the alluvium and ground water throughout much of the area of interest are not accessible for sampling. The samples were analyzed in the field or in a temporary field laboratory by standard geochemical prospecting tests. Copper determinations were made using the biquinoline test and molybdenum using the thiocyanate test. The field results were checked subsequently both with a spectrograph and by using standard wet laboratory methods. DISPERSION OF COPPER AND MOLYBDENUM Most of the samples of alluvium and alluvial soil collected at the land surface have copper contents ranging from 10 to 100 ppm (parts per million). Modern alluvium near the Pima and Mission ore bodies has a higher-than-average copper content, but these high values can be traced along washes upstream past the buried ore bodies to exposed copper mines and prospects closer to the Sierrita Mountains. The distribution of copper-rich float and of copper in the modern alluvium, which is not de- scribed in detail here, is interpreted as being due primarily to mechanical erosion from the exposed copper deposits and as having no relation to the buried ore bodies. The carbonate-cemented zone at the base of the alluvium locally contains very high concentrations of copper. The samples highest in copper are at the extreme base of the alluvium. An area where the copper content ranges from 200 to 1,000 ppm can be traced for 2 or 3 miles to the northeast and down the pediment from the ore bodies (fig. 133.1). Be- cause most of the copper is in the carbonate matrix of the alluvium it is believed that most of the SHORT PAPERS IN THE GEOLOGIC AND R,12 El 111°105’ HYDROLOGIC SCIENCES, ARTICLES 1-146 B—309 R.13E,111°00’ R.l4E, T‘ EXPLANATION 5 S / K\. . A A <18 PPM >18 PPM INDIAN .§ _ .BA NNE R \ .PIMA Ml ii HAFT TUCSON-> Molybdenum in ash of mesquite leaves O 0 « <50 PPB >50 PPB Molybdenum in ground water Cl I <200 PPM >200 PPN Copper in basal alluvium Shari ’ uM‘T— \ CONTOUR INTERVAL 200 FEET DATUM IS MEAN1 SEA LEVEL A 32°00’ /;€’x‘5 Ate/mews 0: k U “D o % O o O T. 17 S, O o 2 MlLES 4 FIGURE 133.1.—Geochemical map showing anomalies resulting from dispersion of ore metals in ground water, Pima district, Arizona. copper is a chemical precipitate from the ground water and is not detrital. The molybdenum content of the ground water ranges from less than 6 ppb (parts per billion) to over 200 ppb. Within the limitations imposed by distribution of wells, anomalous concentrations of molybdenum were traced from the mining area to a point about 8 miles northeast (fig. 133.1). The greater solubility of molybdenum in the ground water as compared to that of copper apparently permits it to be traced for a much greater distance. The molybdenum content of the plant samples ranges from about 10 ppm (parts per million in ash) to about 50 ppm. Among the species compared, molybdenum is highest in mesquite, a deep-rooted phreatophyte. The highest values were found in leaves of mesquite growing in the general area where ground water has a high molybdenum content (fig. 133.1), and we believe that most of the moly- bdenum content of the mesquite is derived chiefly from the ground water and not from the alluvium in which it grows. APPLICATION TO PROSPECTING Tracing the dissolved ore metals in ground water appears to have more significance in prospecting\ than the other methods tried. Molybdenum in the ground water and in mesquite fed by ground water can be traced over 8 miles from the ore. The mo- bility of molybdenum observed here confirms the B—310 results of earlier studies in Russia (Ginzburg, 1960, p. 204). Copper deposited by ground water in the basal alluvium can be traced 2 to 3 miles from the ore. In the search for similar deposits, reconnais- sance studies along major drainage routes apparently can be used to locate large areas With an anomalously high molybdenum content. Widely spaced core drill- ing and chemical study of the basal alluvial con- glomerate Within these areas may be a useful local guide for buried ore. 134. GEOLOGICAL SURVEY RESEARCH 1961 REFERENCES Cooper, J. R., 1960, Some geologic features of the Pima Mining District, Pima County, Arizona: U.S. Geol. Survey Bull. 1112—0, p. 63—103. Ginzburg, I. I., 1960, Principles of geochemical prospecting (English translation of Russian original): Pergamon Press, 311 p. Heinrichs, W. E., Jr., and Thurmond, R. E., 1956, A case history of the geophysical discovery of the Pima Mine, Pima County, Arizona: Geophysical Case Histories, v. 2, p. 600-612. ’X MEASUREMENT OF BULK DENSITY OF DRILL CORE BY GAMMA-RAY ABSORPTION By CARL M. BUNKER and WENDELL A. BRADLEY, Denver, Colo. The bulk density of drill-core samples can be determined by a nuclear irradiation technique in- volving gamma-ray absorption. Comparative data on a series of samples show that the gamma-ray absorption method is much faster and has about the same accuracy as fluid immersion methods for de- termining the bulk density of homogeneous core samples. EQUIPMENT The equipment for measuring bulk density of core samples (fig. 134.1) consists of the following: 1. A 1-millicurie barium-133 source which emits gamma radioactivity having an energy of 0.36 million electron volts (Mev). 2. A sample holder for collimating the radiation from the source through the sample and into the gamma-ray detector in a beam 1.6 centim- eters in diameter. The sample holder is split and hinged to facilitate loading the samples. 3. A scintillation-type detector consisting of a sodium iodide crystal optically coupled to a photomultiplier tube. 4. Electronic circuitry consisting of a high-voltage power supply, a linear pulse amplifier, a dis- criminator circuit, and a ratemeter. A gamma-ray spectrum of the barium-133 source (fig. 134.2) was obtained to determine the pulse- height voltage that corresponds to the known energy peak of barium (0.36 Mev). The discriminator cir- cuit is adjusted to accept gamma-ray energies that are Within a 20-volt range, about :l: 10 pulse-height volts, of the determined voltage at the energy peak to eliminate the measurement of scattered radiation and minimize the effect of natural background radio- High-voltage power suppw V 4 Linear pulse amplifier Recorder l l l l Pulse—height analyzer > Ratemeter fiasco. 7// Components (numbered) described in text FIGURE 134.1.—Diagrammatic sketch of instruments for measuring bulk density of core samples. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 70.0 60.0 50.0 LLJ g \\ 42.0 volts i— 400 _ é \ \ ,_ (:5 33.6 volts or \1 a 0.36 Me / I 3% 30'0 fir t' t d b _ a ia Ion accep e 5‘ discriminator circuit {id // CL / this range of voltage / \ 22.0 volts 20.0 1 10.0 00.0 / 0 200 400 600 800 COUNTS PER SECOND FIGURE 134.2.—Gamma-ray spectrum of barium-133 and en- ergy range used for bulk-density measurements. activity in the samples. The gamma-ray source, sample holder, and detector are enclosed in a cylin- drical lead shield (fig. 134.1), 15.2 cm in diameter, to minimize the radiation hazard to the operator and to reduce the effect of background radioactivity. The source-to-detector spacing without a sample in the sample holder is adjusted to yield a counting rate of 6,400 counts per second and the circuit is adjusted to accept photopeak pulses. This basic counting rate is used for determining the absorption in the samples. Because of drift in instrument re- sponse, slight adjustments in the nominal spacing, about 6.5 centimeters, are sometimes required to maintain the count rate. The average count rate for about a 1-minute in- terval is obtained to reduce the statistical error to less than 10 counts per second, which is the accu- racy of reading the ratemeter and recorder. Repeated readings at successive 1-minute intervals show that the reproducibility of readings is'within these limits throughout the count-rate range observed during B—311 the investigation. This small error in measurement does not affect the interpretation of density. METHOD The instrument was calibrated by determining the relation between percent of gamma radiation absorbed by the sample, sample length, and bulk 90-0 I llllllll Illl llll lll ll llll t“ W l l l 1l / : ._ , _ _. , _ _ , _. _ / _ _. / / — I / / I 80.0 /’ ’ : / __ / I _ l—- / — ._ I] —- 700: 11/ Z I : // / II: I / /_f _ / ,_ 60.o_ , f 2 u, _ Q __ C! .— uJ ‘L .— g '_ a I m 50.0 m _ O _ (I) _ m _ < .— LLl __ i— _ <( a _ i240.0 3 _ o ._ O — _ _J '— _. < _ _ E — I, g _ / — D: : 2 O 30.0 ’ ; / I l— _ t... _ _ .,, _ .._ O — _ a _ _ g _. 20.0——-m _ w _ —_ B _1 _ U a __.‘5 L _ z _ _. ‘5. ._ -— C _ _. 3 __ l0.0 , E ‘30:, o .2 — Control measuvement point —« b i oo‘lllillllllllllll llllllllllllllll“ ' 0.00 LOO 2.00 3.00 4.00 DENSITY BY STANDARD METHOD, IN GRAMS PER CUBIC CENTIMETER FIGURE 134.3.—Ca1ibration chart relating bulk density, sample length, and percent of radiation absorbed by core samples. B.-312 GEOLOGICAL SURVEY RESEARCH 1961 TABLE 1.—Summa7'y of rock types and experimental data [Analystsz R. W. Babcock and G. R. Johnson] Core Length of Gamma-ray Sample Rock type diameter sample Absorption Standard absorption Remarks (inches) (centimeters) (percent) bulk method density bulk density CZ—5 ......... Siltstone ............... 1%. . .. 5.62 68.6 2.40 2.38 6 ......... . .do .................. do ..... 3.33 51.6 2.38 2.40 7 ......... . .do .................. .do ..... 6.14 71.4 2.62 2.35 Sample fractured and vuggy. 8 ......... ..d0 .................. .do ..... 3.61 54.0 2.38 2.39 9 ......... ..do .................. .do ..... 3.12 49.2 2.36 2.34 10 ........ . .do .................. .do ..... 5.62 68.0 2.35 2.38 Fractures and vugs. 11 ........ ..do .................. .do ..... 5.62 68.7 2.38 2.37 12 ........ ..do .................. .do ..... 3.83 55.9 2.35 2.36 13 ........ ..d0 .................. .do ..... 5.83 68.4 2.31 2.32 14 ........ ..do .................. .do ..... 4.70 61.7 2.28 2.29 15 ........ .do .................. .do ..... 4.72 62.5 2 34 2.34 16 ........ Oxidized 1ron formation. do ..... 4.30 59.5 2 38 2.35 Iron forlmation seams through samp e. 17 ........ ..do .................. .do. 322 48.9 2.30 2.30 18 ........ ..do .................. .do ..... 4.60 66.7 2.69 2.69 20 ........ ..d0 .................. .(lo ..... 4.51 68.3 2.84 2.83 21 ........ . .do .................. .do ..... 2.27 43.8 2.64 2,72 Fractures and vugs. 22 ........ do .................. .do ..... 4.65 60.8 2.31 2.30 24. . . . . . . Ferruginous chert ....... .do. 3.75 57 .1 2.58 2.50 Fractures and vugs. L—69 ........ Dolomite ............... 1 ...... 2 , 45 46.9 2 . 81 2.79 70 ........ ....do .................. .do ..... 2.43 44.5 2.64 2.63 71 ........ Quartzite ............... .do ..... 2.50 45.3 2 62 2.60 72 ........ Dolomite ........... 1 . . . .do ..... 1.92 39.2 2 77 2. 73 73 ........ .do .................. .do ..... 2.43 47.3 2.84 2.83 74 ........ Quartzite ............... .do ..... 2.42 44.5 2.61 2.62 75 ........ Dolomite ............... . do ..... 2 . 02 40.9 2. 76 2.70 Fractured. 76 ........ ....do .................. .do. 242 46.1 2.75 2.74 77 ........ Quartzite ............... .do. 1 .85 36. 7 2.62 2. 59 78 ........ Dolomite ............... .do 242 47.7 2.85 2.85 79 ........ ..d0 .................. .do ..... 2.48 46.9 2.73 2.75 80 ........ .do .................. .do ..... 2.51 48.5 2.81 - 2.83 81 ........ Quartzite ............... . do ..... 2. 45 45 . 3 2 . 63 2.63 82 ........ Dolomite ............... . do ..... 2. 43 47. 7 2.85 2.85 83 ........ ....do .................. .do ..... 2.43 44.5 2.62 2.63 84 ........ Quartzite ............... .do 1 .89 37.9 2. 75 2 . 72 85 ........ Dolomite ............... .do. 237 41.4 2.42 2 44 87 ........ ..do .................. .do ..... 2.25 40.6 2.44 2 46 88 ........ .do .................. .do ..... 1.60 31.1 2.40 2.40 density. The samples used for calibration were RESULTS analyzed for bulk density by routine laboratory (fluid immersion) methods. The calibration was limited to sample sizes and densities normally proc- essed by the mass physical-properties laboratory of the U. S. Geological Survey in Denver, Colo. Core- sample diameters of 1 inch and 13/8 inches, lengths from 1.0 to 6.0 cm in increments of about 1 cm, and densities from 0.92 to 3.78 gm per cc were used for. calibration. Sample lengths were determined by making several measurements at the ends of the sample in the area penetrated by the collimated beam of gamma rays. Each of the core samples was placed in the sample holder in the collimated beam of gamma radiation, and the percent reduction in radiation as a result of gamma-ray absorption was determined. The absorption, in percent, of the gamma radia- tion passing through the samples was plotted as a function of sample length and density on a calibra- tion chart (fig. 134.3). The calibration chart was used to compare bulk density measurements obtained by standard labora- tory (fluid immersion) methods (table 1) with bulk- density measurements obtained by the nuclear irradiation technique. The standard laboratory meas- urements were assumed to be correct for this com- parison. The results are given on figure 134.4. Sam- ples containing visible fractures or vugs were not used because preliminary measurements showed that the nuclear irradiation technique may give er- roneous results for these types of samples. These samples can usually be recognized from outward ap- pearances and are set aside for analysis by standard methods, which give more reliable results for this type of sample because of the larger volume of rock used for the measurement. Changes 'in counting rate related to density changes of as little as 0.01 gm per cc can be observed easily on the ratemeter or recorder. Interpretation SHORT PAPERS IN THE GEOLOGIC AND 8 _ Density lower than Density higher than " laboratory laboratory measurement measurement ‘—-—- -——. m l l NUMBER OF SAMPLES J: l 1 Non: Samples with visible— fraciures or vuge were not used. I I - 0.04 -0.02‘ 0.00 0.02 0.04 ‘ DENSITY DIFFERENCE, IN GRAM PER CUBIC CENTIMETER FIGURE 134.4.——Comparison of bulk density measurements determined by gamma-ray absorption method and by standard laboratory methods. HYDROLOGIC SCIENCES, ARTICLES 1-146 3—313 from the calibration chart is less accurate because some bulk density values must be interpolated from the curves. The measurement of bulk density by the nuclear irradiation technique—including the time required to obtain an accurate reading on the ratemeter, measure of the sample length, calculate the percent absorption, and interpret the density with these data —requires only 2 or 3 minutes. The standard labora- tory procedure requires from about 4 to 20 minutes for the same analysis, depending on the method used. Although this investigation was limited to sample lengths between 1.0 and 6.0 centimeters, diameters up to 15/3 inch, and densities from 0.92 to 3.78 gm per cc, the method can be adapted easily to other sample sizes and densities. The equipment is portable and can be transported to field offices or well sites. Bulk density measure- ments of drill core can be completed within a few minutes after core is recovered from a drill hole. A major advantage of gamma-ray absorption method for field use is that it requires neither laboratory conditions nor laboratory apparatus such as analyti- cal balances, water, or mercury, which are incon- venient to use in the field. ’5? 135. MECHANICAL CONTROL FOR THE TIME-LAPSE MOTION-PICTURE PHOTOGRAPHY OF GEOLOGIC PROCESSES By ROBERT D. MILLER, ERNEST E. PARSHALL, and DWIGHT R. CRANDELL, Denver, Colo. A minute-to-minute, hour-to-hour, or day-to-day photographic record can be made of certain geologic processes by the use of a mechanically controlled time-lapse motion-picture camera. Some of the proc- esses that are particularly suited for such a study are glacier motion (Miller and Crandell, 1959), mass wasting (Crandell and Varnes, Art. 57), and erosion of streams and beaches. Time-lapse cameras having an electronic interval-circuit and timer, operated by a solenoid-type plunger, have been used to study stream braiding and stream flow (Fahnestock, 1959). A major advantage of a mechanically con- trolled timing device is that the battery drain is so negligible that the camera can be left unattended for several months. Unfortunately, the camera shutter cannot be tripped by a simple lever attached to a clock. In- stead, provisions must be made to (a) operate the exposure meter circuit for only a short time in order to prolong battery life, (b) protect the shutter from damage by harsh tripping, and (c) reset the timing mechanism to insure the proper interval between exposures. In order to accomplish these things, the shutter GEOLO ‘ICAL SURVEY RESEARCH 1961 B—314 .zamwhwouonn 3329-:338 new 35:8 893-085 kumfiwnowgnflfimfl "55:5 :mzflmm m .m. 3 $5538: can cmfimo .EEBNE Hwy—mam 3:6: £75 35 58m Row .335 33% 3:25» m cg» wwemE :SEEEm v.5: raw—w z: :wfiwwo... 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BEE bmtbm SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1—146 of the time-lapse camera is tripped by an arrange- ment of cams and levers activated by a 6-volt elec- tric motor (fig. 135.1). Two 6-volt “hot-shot” bat- teries in parallel provide power for both the motor and a 6-volt magnetically wound, spring-operated au- tomobile clock used as a timer. The clock is geared from the hour hand so that a shaft rotates once every 24 hours. A timing cam placed on this shaft can vary the range of the exposure interval in hours, or a cam placed directly on the minute hand can vary the tripping interval in minutes. Projections on the timing cam close a single-pole, double-throw microswitch that starts the electric motor. The motor drive shaft is attached to a gear reduction assembly taken from a 1-rpm motor. Snug-fitting tubing is telescoped to couple the gear shaft to the motor. Clamping is not necessary if the fit is snug. The motor must rotate at about 3,600 rmp in order . to be reduced in the gear box to slightly more than 1 rpm. Leading out of the gear assembly is a shaft to which are fixed an activating cam, a reset cam, and a cycle cam (fig. 135.1). As the activating cam turns, it lifts the activating lever, to which are fast- ened a tripping lever and a pressure-release bar. The shape of the activating cam causes the acti- vating lever to rise slightly and to push the tripping lever and, in turn, the camera tripping lever toward the camera. This inward movement closes the cam- era’s photoelectric cell circuit and operates a motor in the camera that opens or closes the camera lens opening in response to light conditions in front of it. Following closure of the photoelectric cell cir- cuit for about 10 seconds, the activating lever is raised further, pushing the tripping lever upward and tripping the camera shutter. Continued rota- tion of the cam shaft lowers the activating lever and turns the reset cam, which opensthe clock micro- switch circuit and shuts off the electric motor. The timing cam on the clock continues to turn until the microswitch lever is released; this closes the reset circuit and causes the cam shaft to rotate until the cycle cam opens the adjacent microswitch and breaks the circuit. The activating cam has now rotated 180° and is in position for the next exposure cycle. Damage to the shutter by excessive inward move- ment during the operation of the photoelectric cell circuit is prevented by adjustment of the upright B—315 position of the tripping lever by means of the ad- justable bolt on the activating lever. The pressure- release bar is fastened to the tripping lever by an adjustable coil spring that absorbs excessive move— ment of the activating lever. Detailed dimensions of the activating mechanism are shown in figure 135.2 (see p. B—316). Two frame counters provide cross checks for co- ordinated operation of the activating lever and camera shutter. One, a ratchet counter, is attached by a metal strip and spring to the activating lever; the other, a rotary counter, is attached by a gear and friction spline to the shutter mechanism of the camera._ . , The camera and timing mechanism are fastened to a magnesium plane table board. A protective aluminum cover with a slanted polished plateaglass window is bolted to the edges of the board. Sponge- rubber gaskets keep the cover tight and dustproof; the, cover and plate can be fitted with latches for padlocks. The planetable board is screwed and bolted to a planetable tripod head. The head is brazed to a tube, the sides of which are cut out to permit access to wingnuts on the underside of the tripod head. The tube slips over a slightly smaller tube which can be placed in the ground and embedded in con- crete. While the upper tube is raised, the camera and planetable board can be adjusted to the desired viewing angle, and the wingnuts tightened. When the tube is lowered, the tripod head and wingnuts are within it and cannot be reached. A latch fastens the tubes together and a padlock prevents tampering. The camera is operated by a spring—wound motor. The winding handle is extended in order to clear ‘the rotary frame counter attached to the camera. The spring motor will expose about 1,200 frames after one full winding. We have found that new 6—Volt batteries will run the electric motor in the timing mechanism unit at least 4 months, and prob- ably longer, exposing 2 frames each day. REFERENCES Fahnestock, R. K., 1959, Dynamics of stream braiding as shown by means of time-lapse photography [abs]: Geol. Soc. America Bull., v. 70, no. 12, p. 1599. Miller, R. D., and Crandell, D. R., 1959, Time-lapse motion- picture technique applied to the study of geological proc- esses: Science, v. 130, no. 3378, p. 795—796. GEOLOGICAL SURVEY RESEARCH 1961 B—316 495:8 ummfiéfifi we Emmaasgfi ”333.5 WEN unwaaiaow mo :Swn—I.N.mMH Hana—h \ 3.5.8.223. fl /®/ 4 __ / x w 833 $28.53 «mvchmmm mhfivmk meJC: 3:500 ‘Ugwt‘bop‘m :OEM 0>°£ 3:..an ‘0 ...Q :< £23 3cm ‘oZ n0=0g mmUer gW‘UEOWU I: . / “396m 3 waEEu mm £53 ® @ WWW m 20: . km «0 #10 l T.‘ 2n N ‘11, W W 1t|1i| L i V Vlk .S_\\.\\1 . 0 i o‘oI Alo .' . in! I 3532 its >35“ OVIV oZ _ m 3.5 0.539 : x 5>2 mEQQE 92:00 T“\I\\\\\I\I\\\ “- Q m 0‘0: \ :3: Tlgkll .r G < 20: \‘l 03:0 E::..EEo:§ x 205 :Xxfik :ono. 633 235530 Fur / / 539.050 #5015 $an £90 in xi" \ 0 SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 136. B—317 LIQUID-LEVEL TILTMETER MEASURES UPLIFT PRODUCED BY HYDRAULIC FRACTURING By FRANCIS S. RILEY, Sacramento, Calif. Work done in cooperation with the US. Atomic Energy Commission In September 1960 the Oak Ridge National Lab- oratory conducted an experiment to test the feasi- bility of disposing of radioactive wastes by injecting them into deep artificial. fractures in nearly im- permeable shale. The vehicle for the simulated wastes was a cement-bentonite grout, which was pumped down an injection well into fractures cre~ ated by the hydraulic-fracturing technique that is used to improve the yields of oil wells. At the suggestion of Wallace de Laguna (written communication, 1960), geologist with the Oak Ridge National Laboratory, three liquid-level tiltmeters of the kind described by Riley and Davis (1960) were used to detect land-surface uplift during the hy- draulic fracturing and grout injection. INSTRUMENTATION The tiltmeter measures differential changes in elevation of the land surface, by reference to a liquid surface that provides a level datum. This is accom- plished by measuring water-level changes in two identical cylindrical pots commonly set 100 to 200 feet apart, and connected by two hoses. One hose, filled with water, is connected to the bottom of each pot, permitting the water surfaces in the two pots to seek a common level. The other hose connects the air spaces above the water in the pots. Differential uplift, or tilting, causes a decline of the water level in the rising pot, and an equal rise of water level in the other pot. In these basic principles the in- strument is similar to the tiltmeters used by Eaton , (1959), Green (Green and Hunt, 1960), and others in investigations of volcanic and tectonic tilting. It differs from these instruments in that measurements in both pots are obtained indirectly from a centrally located displacement device, consisting of a cylinder and micrometer-actuated piston connected at the middle of the water hose. By using a relatively small piston a magnification factor of about 20 is intro- duced, thus making the smallest readable division on the displacement micrometer (0.0001 inch) equivalent to a water-level change of approximately 0.000005 inch in the pots. In the Oak Ridge test three tiltmeters were set up at different distances from the injection, well (fig. 136.1), along lines approximately following the topo- graphic contours. As much as 18 inches of cut and fill was required to provide level lines on which to lay the hoses. The pots rested on concrete piers im- bedded 5 to 7 feet in the ground. For each tiltmeter the data were analyzed by plotting a pair of curves showing water-level change with time in each of the pots. When the water levels were influenced only by temperature-induced volume changes the curves remained parallel. Divergence from parallelism indicated tilting. Graphs of dif- ferential uplift with time were obtained by plotting the differences between the two water-level curves. GROUT INJECTION Two batches of grout were injected into the Cam- brian Conasauga shale, near Oak Ridge, Tenn. Around the injection site the shale on the average dips 20° southeast, but locally the beds are over- turned (Wallace de Laguna, written communication, 1960). The fractures were initiated by a high-pressure sand jet that was slowly rotated so as to erode a horizontal slot through the well casing and cement liner and a short distance into the surrounding shale. Before the grout was injected, fractures were extended some distance away from the well by pumping water at well-head pressures of 1,350 to 2,500 psi. Pertinent ”data on the injections (Wal- lace de Laguna, written communication, 1961) are summarized in the table on the following page. N 0 100 200 FEET / |__L_:_1_A_A_n_l “'20 (average) 455%? Injection well. FIGURE 136.1.—Sketch map of injection site showing layout of tilt-meters along lines B, E, and F. B—318 Injected fluid Injection Depth of s ____________ Total Well-head rate Date injection . volume pressure (gallons (1960) (feet) . » Volume injected (pounds per per Composition percent (gallons) square inch) minute) Sept. 3 934 Water 100.0 1,200 1,350—1,500 80 Grout: 91,567 1,700—2,000 125—156 Water 81.9 ......................... 139 1 Cement 17.5 Bentonite 0.6 9 694 Water 100.0 16,000 1 ,700—2 , 500 280 1 10 694 Water 100.0 4 , 000 ............... 250 Grout: 132,770 2,000—2,300 ?~280 Water 76.8 ......................... 208 1 Cement 22.6 Bentonite 0.6 ' 1 Average rate. OBSERVED UPLIFT The differential uplift between the tiltmeter pier closer to the injection well and the one farther away is plotted against time for each tiltmeter (figs. 136.2 and 136.3). On figure 136.3 the slight eastward tilting along the B and F lines before the start of the grout injection at 1100 hours apparently is a Injecting water / Injecting grout\ :EE 5 ==— GEOLOGICAL SURVEY RESEARCH 1961 regional effect unrelated to the test and presumably due, at least in part, to earth tides. Minor tilting away from the well seems to have begun within 10 to 20 minutes after the start of grouting at 1100 hours, but the major effect, presumably representing the arrival of one or more grout sheets beneath the closer piers, was delayed. 95 to 110 minutes. The pronounced downward inflection (westward tilting) of the F line at 1405 hours may represent passage of the edge(s) of the grout sheet(s) beneath the farther pier. _ When injection of the second batch of grout was begun (fig. 136.2), all three tiltmeters indicated almost immediate uplift of the closer piers, the most distant of which was 243 feet from the injection well. This may have been due to the existence of one or more extensive fracture planes created by injecting large quantities of water the day before. The absence of strong downward inflections of the curves (fig. 136.2) in the early part of the experi- 140 \ V 120 f N /V 7? 100 / 2 x E LINE (I) ‘E '2 8° .2 j E _l D. D . -I 60 E / E B LINE 0: E /—f—/ a D 40 , f F LINE 20 / J \ ‘ o 0600 0800 1000 1200 1400 1600 1800 2000 TIME (E. s. T.) FIGURE 136.2.—Graph showing uplift of closer piers relative to more distant piers, September 10, 1960. SHORT PAPERS IN THE GEOLOGIC AND Injecting water Injecting grout HYDROLOGIC SCIENCES, ARTICLES 1-146 13—319 #— _ E I fig 40 E A E T D 2 3 LINE _l < X l: 8 20 / I I." E I ‘ ...... a: o __.*//—/.\l .............. E g ............ F LINE & ..... Q - ................ 0 uuuuuu 'I' . . 0800 1000 1200 1400 1600 1800 2000 2200 TIME (E. S. T.) FIGURE 136.3.——Graph showing uplift of closer piers relative to more distant piers, September 3, 1960. ment suggests that the more distant piers on all three lines also may have started to rise almost immediately, perhaps through the action of water trapped in the fractures ahead of the advancing grout. 7 The observed tilting seems consistent with the -asumption that the grout spread out as one or sev- eral thin, sill-like sheets moving through and gen- erating fractures that mostly tended to follow bedding planes. 137. REFERENCES Eaton, J. P., A portable water-tube tiltmeter: Seismol. Soc. America Bull, v. 49, no. 4, p. 301—316. Green, G. W., and Hunt, C. B., 1960, Observations of current tilting of the earth’s surface in the Death Valley, Cali- fornia, area: U.S. Geol. Survey Prof. Paper 400—B, art. 124, p. B275, B276. Riley, F. S., and Davis, S. N., 1960, A tiltmeter to measure surface subsidence around a pumping artesian well [abs]: Jour. Geophys. Research, v. 65, no. 5, p. 1637. 6% \ _ \. 2 . _ W., , ~./ A METHOD OF RECORDING AND REPRESENTING GEOLOGIC FEATURES FROM. LARGE-DIAMETER DRILL HOLES By ELMER H. BALTZ and JAMES E. WEIR, JR., Albuquerque, N. Mex. Work done in cooperation with the US. Atomic Energy Commission The Geological Survey is currently studying ground-water conditions and disposal of radioactive waste in the vicinity of Los Alamos, N. Mex., in sup- port of activities on the Los Alamos Scientific Lab- oratory. As part of this work the writers examined the geologic features on the walls of large-diameter holes drilled in the Bandelier tuff of Pleistocene age. The holes, which were drilled with a bucket auger, ranged from 3 to 6 feet in diameter and from 49 to 108 feet in depth. The methods and geological equipment described in this report were devised by the writers for quickly recording and representing features such as joints, cavities, and lithologic units. The drill holes were examined from a metal per- sonnel cage (fig. 137.1) that was lowered and raised by a powered crane. The cage is 2 feet in diameter and is equipped with electric lights and a two-way portable radio for communication with the surface. Air circulation in the holes was maintained by an exhaust fan at the surface connected to a flexible tube extending nearly to the bottom of the holes. The writers decided that the geologic. features exposed in the walls of the holes would be most easily recorded and most useful if they were plotted on diagrams representing cores from the holes, rather B—320 GEOLOGICAL SURVEY RESEARCH 1961 FIGURE 137.1.—Equipment used in recording geologic features in large-diameter drill holes. A, personnel cage; B, cardboard tube with graph paper attached; C, sighting bar; D, arc scale with bubble level. Photo by Roy Stone. than on flat diagrams representing the walls of the holes. For this purpose cardboard mailing tubes with outer diameters of 1.5, 2, and 3 inches were used to correspond to drill holes with diameters of 3, 4, and 6 feet, respectively. Printed semitrans- parent graph paper, ruled in inches and tenths of inches, was fastened to the tubes with rubber cement or drafting tape. The line on the tube diametrically opposite the joint line of the paper was designated as north and was used as the reference from which all measured points were plotted. The north, south, east, and west lines were marked on the graph paper, and intervals of depth from the surface were marked to scale. Scale is automatically determined by ratio of the diameter of the tube to that of the hole. Thus, if the tube is 3 inches in diameter and the hole is 6 feet in diameter, the scales, both circumferential and vertical, are automatically 1 inch equals 2 feet. A sighting bar (fig. 137.1) and a Brunton pocket transit were used to determine the north and south points of the holes. Lower extensions of the metal leaves of the sighting bar fit into the hole; the leaves slide on the wooden bar and are adjustable to fit holes of different diameters. The north’ and south sides of the hole were determined by orienting the bar with the aid of a Brunton pocket transit. A steel tape, weighted at the end, was secured at the north point at the top of the hole and hung as a pendulum to the bottom of the hole. The tape was used as the north reference on the wall of the hole, and also for depth determinations. In some drill holes additional tapes were hung at the south, east, and west points of the holes. During the first “run” down the drill hole in the personnel cage the wall of the hole was marked with carpenter’s crayon at standard intervals of depth. Measuring, recording, and plotting of data usually were done bottom to top as the cage was raised. Most of the work was done by a two-man crew; one geolo- gist plotted on the graph paper of the tube, while the other geologist measured and described geological features observed on the wall of the hole. A two-man crew proved to be considerably more efficient than one man. In the 3- and 4-foot diameter holes, meas- urements were made with a flexible 6-foot metal tape ——but this was impractical in the 6-foot diameter holes because the distance to the wall from the cage suspended in the middle of the hole was too great. A graduated aluminum arc scale with a bubble level (fig. 137.1) was built to measure circumferential dis- tances in these larger holes. The curvilinear length of the scale is 5 feet, and the radius of the arc is 3 feet. To avoid confusion the observer gave all measurements to the plotter in terms of feet east or west of the north line at each station within the hole. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 o o’:’ 99 ’9 8—321 033302.? 9,3,0/ FIGURE 137.2.——Sketch of core diagram showing methods of determining strike and dip of joints. The completed plot of geologic features is a three- dimensional representation of a core of the rock penetrated by the drill hole. Strike of bedding, joints, veins, fissures, and other features may be obtained by orienting the tube on a flat piece of graph paper. Two points of equal depth on the geologic feature are projected down the ruled lines of the tube to the graph paper (fig. 187.2). The strike is deter- mined with a protractor from a line drawn through the points on the flat paper. If a third point on the feature at a different depth is projected down the tube to the flat paper, the dip can be determined = graphically, or trigonometrically by means of a 3- point equation. Probably this method of three-di- mensional representation is applicable to other geo- logic and engineering problems. The diagrams of the cores can be drafted and reproduced flat so that they can be rolled and held together by paper clips or tape. If a flat representa- tion of the wall of the hole is needed, the semitrans- parent graph paper is simply turned over and a tracing is made of the reverse side. The latter form of representation shows the wall of the hole as seen by a person inside the hole. ’X B—322 GEOLOGICAL SURVEY RESEARCH 1961 ANALYTICAL AND PETROGRAPHIC METHODS 138. METHODS FOR DECOMPOSING SAMPLES OF SILICATE ROCK FRAGMENTS By JOHN C. ANTWEILER, Denver, Colo. Three procedures are given below for the decom- position of silicate rock samples that have been neither crushed nor ground. In minor element analy- ses, crushing, grinding, sieving, and splitting pro- cedures can introduce the following types of inac- curacies: (a) Errors of selective subtraction owing to loss of air-borne dust and spatter particles which may be greatly enriched in certain minor elements; (b) errors of addition from abrasion of grinding equipment, exposure to atmospheric dust, and hand- ling; (c) chemical changes such as loss of sulfur from sulfides and oxidation of iron or copper to a higher valence state; and (d) inhomogeneities caused by unequal distribution and segregation of particles having different densities. Some of these errors can affect the accuracy of analyses for major elements (Hillebrand and others, 1953, p. 811; Kolt- hoff and Sandell, 1952, p. 242), but they may affect the accuracy of analyses for minor and trace con- stituents much more. To minimize some of these uncertainties, G. J. Neuerburg prompted the author to devise techniques for decomposition of 4—gram, or larger, fragments of rock. Many profitable sugges- tions were received from L. C. Peck during the work. The procedures explained here lessen chances for selective subtraction and addition caused by grind- ing ; they fail to lessen most of the errors of chemical change; they eliminate segregation and improper representation in a specific sample, but emphasize inhomogeneities in a series of samples. The pro- cedures are useful for certain studies such as trace element distribution; they are not intended to re- place standard rock sampling and analytical pro- cedures. Several standard methods for silicate decomposi- tion will eventually decompose a 4-gram rock frag- ment, but reagent and time requirements generally are excessive. The hydrofluoric acid procedure and two fusion procedures described below readily de- compose 4-gram fragments of rock in reasonable time and require only moderate quantities of rea- gents. The acid procedure has been used to decom- pose 50-gram and larger pieces of rock. Consump- tion of reagents per gram of rock in most cases is no greater than that required for a powdered sample. The final solution obtained by use of the three decomposition procedures described is designed for determination of uranium as uranyl nitrate. De- . terminations of some minor elements are preferably made from chloride or sulfate solutions. If such determinations are contemplated, modification in the solution procedures after decomposition is complete can readily be made. For example, in the hydro- fluoric acid procedure the dry fluorides can be con- verted to sulfates by fuming with sulfuric acid, or they can be converted to chlorides by fuming with perchloric acid followed by solution in hydrochloric acid. HYDR-OFLUORIC ACID PROCEDURE The decomposition of finely divided silicates by HF is an extremely vigorous reaction. It is usually moderated by water and one or more strong acids such as HN03, H2804, H0], or HC104. On the other hand, the decomposition of rock chips by HF is a quiet reaction and other acids are preferably omitted. For example, a 4-gram diabase chip was completely decomposed in 6 hours by 75 ml HF; a similar chip was not entirely decomposed in 4 days by the same volume of HF plus an equal volume of HN03. Place a weighed rock fragment in a vessel resistant to HF, add 10 to 15 ml concentrated HF (48 percent or stronger) for each gram of rock. Place a close- fitting cover over the veSSel, and digest its contents 24 hours at steam bath temperature (~85°C). After digestion remove the cover, stir occasionally, and evaporate to dryness. Add for each gram of sample about 30 ml of 50 percent (v/v) nitric acid; digest the covered mixture, stirring occasionally, for 2 hours at steam bath temperature, then evaporate to dryness. Again add nitric acid, and repeat the diges- tion and evaporation procedures. Dissolve the nit- rates in 25 ml of 71/2 percent (V/v) HN03 per gram of rock and filter. If any rock remains, repeat the hydrofluoric acid decomposition procedure. If the residue consists only of zircon or other HF-insoluble SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 fine-grained minerals, fuse it with potassium pyro- sulfate or sodium carbonate by conventional silicate analytical procedures. Decomposition of chip samples by HF is usually preferable to decomposition by fluxes because (a) much larger samples can be handled and (b) greater concentration of minor elements in the analytical solution is possible; only volatile reagents are added and silicon is removed as gaseous tetrafluoride. It is therefore sometimes possible to lower the limit of detection of minor elements, and to improve the precision of their determination. It is not always possible to use the HF procedure because fluorine (which is probably never completely removed) interferes in some analytical schemes; rocks, of course, cannot be analyzed for trace ments that form volatile fluorides. Addition of boric acid after the evaporation of HF somewhat facilitates conversion of fluorides to nitrates through formation of volatile BF... Excess boron can subsequently be removed as methyl borate formed by the addition of methyl alcohol. Platinum, gold, polyethylene, and glassware lined with commercial wrapping plastics (A. P. Marran- zino, written communication, 1961), can be used for the HF decomposition. Plastic-lined containers are not suitable, however, for conversion of fluorides to sulfates, perchlorates, or nitrates. SODIUM PEROXIDE FUSION PROCEDURE Sodium peroxide is a powerful rock disintegrator, but at high temperature it also attacks most of the materials used in the manufacture of laboratory crucibles. Platinum and gold cannot be used, and nickel is far from satisfactory for rock fragment fusion. Zirconium, however, resists sodium peroxide for prolonged periods of time at temperature of as much as 900°C. Weigh about 15 grams of sodium peroxide into a zirconium crucible, place a rock fragment weighing as much as 5 grams on top of the peroxide, and then sprinkle in enough additional peroxide to cover the sample completely. Cover the crucible and contents, heat over an open burner, slowly at first, and finally at red heat until the fragment is dissolved (usually 1/2 to 1 hour). Carefully add water to the cooled melt in a covered beaker. After subsidence of the vigorous reaction, dilute with enough water tomake a volume of 100 ml per gram of rock. Quickly add enough concentrated nitric acid to yield a solution that has a nitric acid strength of 71/2 percent by volume. Rapid addition of all the acid required eliminates efferves- cence, inhibits formation of gelatinous silica, and B—323 yields a solution that is readily and quickly filtra- ble (L. C. Peck, oral communication, 1957). Add 0.1 grams sodium nitrite to reduce manganese which is often present in sufficient quantities to cause turbidity. Filter the solution and repeat the pro- cedure on any undissolved residue. One zirconium crucible will last for at least 150 sodium peroxide fusions (D. W. Richardson, written communication, 1956). Iron crucibles may be {used for sodium peroxide fusions, but they introduce considerable iron to the sample, and they are not generally suitable for re-use. SODIUM CARBONATE-BORIC ACID PROCEDURE A carbonate-boric acid flux prepared as outlined below is more effective for silicate decomposition than either sodium carbonate, or boric acid alone, or mechanical mixtures of borax or boric acid and sod- ium carbonate (L. C. Peck, oral communication, 1957). Prepare the flux by melting 3 parts by weight of sodium carbonate together with 1 part of boric acid. Break the cooled melt into pieces weigh- ing 2 to 4 grams. Preheat the weighed rock sample to 650°C to remove water. After cooling, add to the crucible containing the rock sample about 4 grams of flux for each gram of rock. Heat the crucible and contents rapidly to 900°C, and maintain this temper- ature for 11/2 hours. If frothing occurs, lower the temperature until frothing subsides. Dissolve the cooled melt by digestion for 3 hours at steam bath temperature in 75 ml of 71/; percent (v/v)’ HN03. If there is any turbidity or rock residue, filter the solu- tion, decompose the residue by standard analytical procedures, and add the solution to the above filtrate. This fusion procedure is fast, economical, and effective on many kinds of rocks. Loss of samples through intumescence is its greatest shortcoming; constant attention during the fusion is necessary. The method should be tested on each new rock type before using samples that cannot be replaced or duplicated. The interference of bOron in some analy- tical schemes is an important censideration before using this procedure. All three of the foregoing procedures have been successfully used to‘decompose rocks as different in composition as basalt and granites. Their application and usefulness to diabasic rocks is reported by Neuerburg and Granger (1960, p. 780—782). The HF procedure usually is‘ preferable to the others unless the analyses are being made'in the field, or unless subsequent analytical procedures .will be hampered by the presence of fluorine. The sodium peroxide procedure is best in the field because it is B—324 the fastest, and is less apt to cause difficulty through intumescence. The sodium carbonate-boric acid pro- cedure usually is preferable to sodium peroxide fu- sion in a laboratory because fusion conditions can be controlled to prevent intumescence, and complete decomposition is more likely to be obtained with the first fusion. Reagent purification, which is essential in minor element analyses, is much simpler for the HF method than it is for the fusion methods. 139. GEOLOGICAL SURVEY RESEARCH 1961 REFERENCES Hillebrand, W. F., Lundell, G. E. F., Bright, H. A., and Hoff- man, J. I., 1953, Applied inorganic analysis: New York, John Wiley and Sons, Inc., 1034 p. Kolthoff, I. M., and Sandell, E. M., 1952, Textbook of quantita- tive inorganic analysis: New York, The Macmillan Co., 759 p. Neuerburg, G. J., and Granger, H. C., 1960, A geochemical test of diabase as an ore source for the uranium deposits of the Dripping Spring district, Arizona: Neues Jahrb. Mineralogie Abh., v. 94, Festband Ramdohr, p. 759—797. 6% FATIGUE IN SCINTILLATION COUNTING By FRANCIS J. FLANAGAN, Washington, D. C. Work done in cooperation with the US. Atomic Energy Commission When National Bureau of Standards radium gamma-ray standards (Mann, 1956) were counted as reference points for normalizing data, variations were noted in the counting rates. It was soon estab- lished that the variations were due to photomulti- plier fatigue, and that radium from other sources caused similar effects. Although many papers on photomultiplier fatigue have been published, neither the primary cause of the fatigue nor a method of avoiding it have been discussed. Caldwell and Turner (1954) suggest, however, that the effect may be due to the low—energy gamma radiation of the radium serles. To determine the effect of gamma radiation a 2- microgram ampoule of radium was placed for 1 hour on a 2 inch by 2 inch crystal of sodium iodide coupled to a 6292 photomultiplier. The photomultiplier out- put was fed into a 100-channel analyzer whose gain was set so that the complete spectrum was taken in 55 channels. A l-minute count was made during the first minute of each l-minute interval for 1 hour, the counts obtained being recorded on tape. The initial counting rate for each channel is shown in figure 139.1, and the losses for each channel in 1 hour, expressed as percent of the first count in the channel, in figure 139.2. Losses occur in all channels except 53, and these losses (except for irregularities between channels 45 and 55 due to low counting rates) increase with decreasing energy and with increasing counting rates. The relative error, however, decreases in most counting experiments with increasing counting rates. To decide whether the variations in the counting rates were significant, a statistical technique was selected in preference to some arbitrary percentage loss or gain not to be exceeded. The Poisson distri- bution, whose mean and variance are equal, is com- monly used in radioactivity counting. The initial count in any channel can represent both the mean and variance of an infinite number of observations if no changes take place in the counting conditions. If changes do occur, as they do in the present study, the variance for any channel can be calculated and then compared with that expected if there were no change. The comparison is made by the statistic X‘-’/df (chi squared over degrees of freedom), which is equal to the computed variance divided by the initial count. The computed values of the statistic, together with the upper limits for the 95-percent and the 99.95-percent probability level, are shown in figure 139.3. The computed statistic for only 8 of the channels is below the allowable limit for the 95-percent level, and hence the computed variances are not signifi- cantly greater than the Poisson variances. The SHORT PAPERS IN THE GEOLOGIC AND | I l I l T 100,000“ 10.000— COUNTING RATE (counts per minute) 1000— ‘ — 300 1 ‘ l J_ l I J A 10 20 30 40 50 CHANNEL NUMBER FIGURE 139.1.—Initial counting rate per channel. statistic for 30 of the 43 channels exceeds the allow- able value at the 99.95-percent level. This plot, like the one for counting-rate losses, shows that the most significant variations in counting rates occur in the low-energy part of the spectrum. CHARACTER OF THE SOURCES Of the gamma sources used in preliminary tests in this investigation (C060, Cs137, and radium solu- tions) only the radium sources cause significant ._- U1 1 #17, ,4 ”fl? m _ m 0 l _l ‘ EA 5% . 010» E (55 23 ,: Z 3 O U l —< U'l _ Aigfifi“ l l I 1 1 20 3O CHANNEL NUMBER 40 FIGURE 139.2.——Counting rate loss per channel. B—325 losses and emit the low-energy gammas proposed by Caldwell and Turner (1954) as a possible cause of photomultiplier fatigue. If the effect is due to these gammas, it should be noticeable when counting a radium-DEF solution, since Pb 210 is a source of ’ low-energy gammas. One milliliter of a DEF solu- tion was counted, but no loss was noted for this aliquot, which counted about 10,000 cpm under the same conditions that yielded 4,000 cpm for the 0.1 microgram of radium. The main solution from which this aliquot was taken was then counted with similar results. These low-energy gammas, there- fore, cannot be the sole cause of fatigue. ‘ . l i HYDROLOGIC SCIENCES, ARTICLES 1—146 i a l ~\ I X 10— ‘ ‘ l I Xz/df (12)o_ 999=2.9o ”‘2‘"7 ______ T‘“" X /df (12),,95 =1.75 ______ 7-—‘--— ______ I l 1- ‘ o.5~ 1 1 1 5 10 20 30 4o 50 I ’ CHANNEL NUMBER i FIGURE 139.3.—Variation of counting rate per channel. On reexamining the character of the sources used, one sees that each was contained in glass and emits beta radiation, but that the radium solutions emit the largest number. The question then arises whether bremsstrahlung, resulting from the inter- action of the beta-rays with glass, could be respon- sible for the fatigue. ’ BREMSSTRAHLUNG FROM BETA PARTICLES Two “gamma-free” beta-ray sources were avail- able for testing this hypothesis. When a two-ounce B—326 glass jar containing nickel sulfate recrystallized with Ni 63 (E3 = 0.063 Mev) was counted with a crystal coupled to a 6342 photomultiplier, a loss of 0.7 percent of the initial counting rate of 268,000 cpm was obtained. When a T1 204 source in the Original bottle shipped from Oak Ridge National Laboratory was placed on the same crystal-tube combination, it lost 11.4 percent of its original counting rate (350,000 cpm) in one hour. The same bottle, at a different time, lost‘26 percent in one hour with the 6342 photomultiplier, and gained 9 and 12 percent with a 6292 and 5819, respectively. Cathey (1958) attributes gains and losses for different photomultipliers to the amount of cesium on the dynodes. As a further test, one ml of an uncalibrated Co 5° source was placed in a vial and counted, using the same 6342 photomultiplier; this gave 360,000 cpm with no noticeable loss in an hour. An aliquot of a solution of T1204, a pure beta emitter, was added to the cobalt source in the vial. This addition in- creased the activity of the source by 35,000 cpm, and this mixed source lost 0.8 percent of its total counting rate in one hour. When a second equal aliquot of the thallium was added, theISOurce lost 2.3 percent in one hour. Another equal aliquot of the thallium source, dried on cellophane and placed on the same crystal, yielded 12,000 cpm with no noticeable loss. If bremsstrahlung can cause fatigue, should have similar effects. X-rays A solid uncalibrated 140. GEOLOGICAL SURVEYRESEARCH 1961 0060 source taped to a crystal yielded 130,000 counts in 16 seconds. The crystal was then exposed to white‘ X-rays with a peak at about 10 Kev for ten seconds. When the X-ray so urce was removed and the cobalt counted immediately, it yielded 63,700 counts—a loss in counting rate of 51 percent. After 15 minutes the photomultiplier had recovered so much that the loss in counting rate was only 12 percent. The hypothesis ascribing fatigue to bremsstrah- lung therefore appears tenable, and since brems- strahlung and X-rays are similar, it is consistent with the observation of Marshall and others (1947) that “the presence of fatigue is a serious defect” in the use of photomultipliers as X-ray detectors. From these experiments it may be inferred that the photomultiplier fatigue may be primarily caused by bremsstrahlung resulting from the interaction of beta particles with the glass ampoules. REFERENCES Caldwell, R. L., and Turner, S. E., 1954, Gain variation of photomultiplier tubes: Nucleonics, v. 12, no. 12, p. 47—48. Cathey, L., 1958, Fatigue in photomultipliers, in Scintillation Counter Symposium, 6th Washington, 1958, Proc: I R E Trans on Nuclear Sci., v. NS—5, no. 3, p. 109—114. Mann, W. B., 1956, The preparation and maintenance of standards of radioactivity: Internat. J our. Applied Radia- tiOn and Isotopes, v. 1, p. 3—23. , Marshall, F. H., Coltman, J. W, and Hunter, L. P., 1947, The photomultiplier X- -ray detector: Rev. Sci. Instruments, v. 18, p. 504—513. : 5% A SIMPLIFIED METHOD OF CONCENTRATING AND PREPARING CARBONATE SHELLS FOR C“ AGE DETERMINATIONS By THOMAS C. NICHOLS, JR., Denver, Colo. Because handpicking of carbonate shells from a field sample is laborious and time.» consuming, a simpler method of concentrating and preparing these shells for C14 age determinations was developed using already existing equipment and reagents of the US. Geological Survey Laboratory at Denver. Three steps are involved: determining the feasibility of removing shell material from the sample matrix, disaggregating the sample and concentrating the shell material, cleaning the shell material. All rea- gents and containers coming in contact with the shells must be free of contaminating carbon. FEASIBILITY OF REMOVING SHELLS FROM SAMPLE The feasibility of removing shells from a sample depends upon the size and condition of the shells and also the condition, texture, and composition of the matrix. It is difficult and tedious to process SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 shells smaller than 420 microns—but if necessary, a modified procedure will reclaim some of the smaller ones. The matrix must be reasonably free of ferru- ginous, siliceous, and carbonate cementing materials. These materials, if present in large quantities, are difficult to remove without destroying the shells. The size and sorting of the matrix are of concern only in actual separation techniques. SEPARATING SHELLS FROM MATRIX The sample is presoaked for 16 hours in a 3.5 per— cent solution of sodium polyphosphate in distilled water to disperse the clays and other fine materials which tend to cement the matrix together. These dispersed fine materials are discarded first by wet screening the sample through a US Standard No. 200 screen. The disaggregated portion remaining on the screen is dried and passed through a U.S. Standard No. 40 screen, thus concentrating the larger shells with the coarse fraction of the sample. The —40-mesh fraction is set aside in a closed container for possible further processing. The +40-, mesh fraction is now examined for sorting of grains rather than sorting for shells and shell fragments. Most of the shells and shell fragments are in the same size range as the accompanying sand grains and cannot be isolated by screening, but there are usually some large shells which can be isolated. Therefore, the +40-mesh fraction is sized with appropriate screens to isolate the larger .shells and to divide the remaining portion into well-sorted fractions containing the smaller shells and shell fragments. At'this point, there might be a sufficient quantity of isolated shells for age determination. If" not, it is necessary to isolate shell material from the finer of the +40-mesh fractions. 4 . By taking advantage of their shapes and rela- tively light densities, shells and shell fragments can be rapidly and completely separated from the heavier more equidimensional sand grains by air elutriation. A large elutriation apparatus similar to that described by Frost (1959, p. 886) is effective. B—327 Light-mineral impurities such as gypsum will separ- ate with the shells, but these can be eliminated by elutriating a second time, and readjusting the air stream velocity. Fractionation of shell material from the minus 40-mesh fractions by air elutriation is impractical because of the static electricity gener- ated. This problem is overcome if distilled water is used as an elutriating medium. CLEANING SHELL MATERIAL FOR C” DETERMINATIONS The concentrated shell material from the different fractions can now be added together and more closely scrutinized for impurities. There will probably still be clay imprisoned within the shells, and possibly some secondary lime encrustations on the outer surfaces. At this point, the shells should be gently fractured, but not pulverized, in a mortar with a pestle. The shells are placed in a beaker and allowed to soak in 3.5 percent solution of sodium polyphos- phate in distilled water for 1 to 2 hours; then they are processed in an ultrasonic transducer for about 15 minutes or until the shells appear to be clean. The ultrasonic transducer is very effective in break- ing up clays and secondary encrustations ordinarily immune to other treatment. Very fragile shells must be treated sparingly in the ultrasonic transducer as they tend to disintegrate. After this treatment, repeated washing and decanting with distilled water will remove impurities present as suspended fines. The clean shells remaining in the beaker are covered with a watch glass and allowed to dry slowly under a heat lamp. The dry shells are suitable for a Cl4 age determination. , There will be many problems peculiar to indi- vidual samples. The above procedure is meant to be a general outline and can be revised to meet the demands of any individual sample. REFERENCE Frost, I. C., 1959, An elutriating tube for the specific gravity separation of minerals: Am. Mineralogist, v. 44, p. 886— 890. . v ‘ 6Q B—328 GEOLOGICAL SURVEY RESEARCH 1961 141. COLORIMETRIC DETERMINATION OF IRON IN SMALL SAMPLES OF SPHALERITE By LEONARD SHAPIRO and MARTHA S. TOULMIN, Washington, D. C. The increased use of the “sphalerite geothermom- eter” (Kullerud, 1953, and Barton and Kullerud, 1958) that correlates the temperature of forma- tion of the sphalerite with the amount of iron sub- stituting for zinc in the crystal structure, has de- veloped a need for a simple, rapid, and reliable procedure for determining the amount of iron in sphalerite. Because natural sphalerite is commonly fine grained and/ or compositionally zoned, the analy- tical method used should be suitable for small sam- ples, preferably single small fragments. The method described here has been utilized to trace changes in composition from the center to the margin of zoned sphalerite crystals. A method adapted ,(Yoe and Jones, 1944) to meet these requirements is based on the use of disodium— 1,2—dihydroxybenzene—3,5—disulfonate (Tiron). It is a simple but flexible procedure, being suitable for visual estimation for greatest simplicity, or mea- surement in a photometer for increased accuracy. Samples from 0.6 to 30 mg have been used, and iron contents ranging from 0.1 to about 20 percent have been determined. The procedure is described for a 10 mg sample for the range 0 to 1.1 percent iron. Smaller size sample may be used if necessary, and small aliquots of solutions may be used Where iron concentrations are high. The sphalerite is decomposed with aqua regia in a test tube, heated to drive off oxides of nitrogen and sulfur that may have been formed, and the re- maining salts taken back into solution with hydro- chloric acid. Tiron and a buffer are added, and the purple color produced is compared with a set of standard iron solutions, either visually or in a photometer using a wave length of 550#- REAGENTS 1. Standard iron solution. Dissolve 121 mg FeC13 '6HgO in water containing a few ml of hydro- chloric acid and dilute to 250 ml in a volumetric flask. 2. Buffer solution. Dilute 80 g of ammonium acetate and 30 ml of acetate acid to 2 liters. 3. Tiron. Pure powdered disodium—1,2—dihydroxy— benzene—3,5—disulfonate. 4. Concentrated hydrochloric acid. Contained in a dropping bottle. 5. Concentrated nitric acid. Contained in a dropping bottle. 6. Zinc chloride solution. Dilute 210 mg of ch12 to 100 ml in a volumetric flask. PREPARATION OF STANDARDS To a series of 22 X 175 mm test tubes add: 0.0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.1 ml of the standard iron solution with a graduated pipette. Add 6.7 ml of zinc chloride solution, 3 drops of concentrated hydrochloric acid, and 10 to 20 mg Tiron to each tube. With a graduate add 20 ml of the buffer solution to each tube, and add water to make the volumes equal to 30 ml. Invert to mix. The re- sulting solutions correspond to 0.0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.1 percent iron when a 10 mg sample is used, and are stable for a few days. PROCEDURE 1. Crush a small crystal of sphalerite with a mortar and pestle. 2. Weigh 10 mg of the sample and transfer to a dry test tube. 3. Add about 6 drops of concentrated nitric acid and 6 drops of concentrated hydrochloric acid. 4. Evaporate to dryness over a Bunsen burner, then heat with the full flame of the burner for 10 to 20 seconds. 5. Allow to cool for several minutes. 6. Add 3 drops of hydrochloric acid and wet the bottom of the test tube by rotation, then add 1.1 ml of water. 7. Add 10 to 15 mg of Tiron powder. 8. Add 20 m1 of buffer solution and water to 30 ml. Mix by inversion. 9. Compare with the set of standards. A visual comparison can be made to obtain a value to the nearest 0.1 percent, or better results can be obtained by comparison in a photometer at a wave length of 550/1. ,The procedure may be modified by using smaller samples or by dilution of the sample after step 6 and use of a portion of the diluted solution. If single fragments of 0.5 to 2 mg are used, it may be necessary to repeat steps 3 and 4 to obtain com- plete decomposition. DISCUSSION AND RESULTS Accuracy and precision of the procedure were studied using 1 to 2 mg of five synthetic sphalerites of known composition. The samples were analyzed at four different times to provide reproducibility data, and the averages obtained were compared with the known iron content. The samples also SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 TABLE 1.~—Dete1‘minations of percent iron in synthetic sphalerite Proposed colorimetric ‘ method Conventional , Average Known ceric Sample ' _ content titration “DUNN-b oar-unocc- mmweuv cocoa-loo wowms. p—qonauo wqmwm wi—Mi—O wuwma— mexleo u—xnoon-i— *NGac‘l a—xlwoou— macao-q up. u... h—IM b—n—n Ha H.— .—-._. were analyzed by C. A. Kinser with a conventional ceric sulfate titration procedure as an additional basis of comparison. The results are shown in table 1. Samples of approximately 1 to 2 mg were weighed directly into the decomposition test tubes. Such weighings may be expected to have an accuracy of about 10 percent. The replication of results shows a spread of about 10 percent from the known iron concentration, but deviations of the averages from the known are generally better, indicating that 142. B—329 chance variations such as weighing errors can be re- duced by replication, or the use of larger samples. Manganese, sometimes present in significant amounts, was found to introduce no error up to 10 percent manganese. Copper present in amounts greater than those found in natural sphalerites also had no effect. The ability to use very small samples, especially small single fragments, plus the simplicity of the procedure, provide a useful tool for determination . of the iron content of sphalerite. The method is readily adaptable to use in the field. REFERENCES Barton, P. B., Jr., and Kullerud, Gunnar, 1958, The FeS— ZnS—S system: Carnegie Inst. Washington, Ann. Rept. Director, Geophys. Lab., Paper 1289, p. 227—229. Kullerud, Gunnar, 1953, The FeS—ZnS system, a geological thermometer: Norsk geol. tidsskr., v. 32, no. 2-4, p. 61—147. Yoe, J. H., and Jones, L. A., 1944, Colorimetric determination of iron with disodium-1,2-dihydroxybenzene-3,5-disulfon- ate: Anal. Chemistry, v. 16, p. 111—115. ’R‘ INDIRECT SEMIAUTOMATIC DETERMINATION OF ALUMINA WITH EDTA By J. I. DINNIN and C. A. KINSER, Washington, D. C. In the course of investigating the application of EDTA (disodium ethylenediaminetetraacetate dihy- drate) titrations to the determination of alumina in geological materials, a new indirect titration system has been developed. Because of the uncertainty of most of the methods available for alumina it is useful to have auxiliary procedures, as different in nature as possible, by which to check results. The new method involves the addition of a con- trolled excess of EDTA and titration of the excess with ferric chloride solution using Tiron (disodium 1,2—dihydroxybenzene 3,5—disulfonic acid) as an indicator. The Tiron-ferric chloride titration system has been used for the direct determination of iron (Haberli, 1954) and the indirect determination of zirconium (Manning, Meyer, and White, 1955) but as far as is known it has not previously been used for the determination of alumina. Other EDTA titration systems for aluminum tested in this laboratory have been unsatisfactory. Indirect titration with cupric sulfate using Pyroca- techol Violet as indicator (Suk and Malat, 1956) gives excellent results with pure aluminum Solutions. The system is extremely susceptible to changes in the chemical environment however, and its use must be rigorously restricted. In titrations performed in pyridine-acetate buffered solutions, the presence of moderate concentrations of phosphate or sulfate prevent the formation of an end point; perchlorate or chloride have significant effects on the location of the end point. Indirect titrations with ferric chloride using salicylic acid (Milner and Woodhead, 1954) or sulfosalicylic acid (Patrovsky and Huka, 1957) as indicators give indistinct end points under the conditions of the tests. The Tiron-ferric chloride titration system is less subject to interferences than the Pyrocatechol Violet- cupric sulfate system and appears to have several B—330 advantages over other methods proposed for the determination of alumina with EDTA. The reaction appears to be stoichiometric, the solution does not have to be boiled, and the end point is very sharp. The sharpness of the end point can be ascribed in part to the use of elevated temperatures, but the use of an automatic colorimetric recording titrator is also a major contributing factor. The recording colorimetric titrator used‘ in this investigation is similar to one described by Shapiro and Brannock (1955) but differs in several features. The titrating solution is fed by a motor-driven syringe rather than by gravity. The light beam from a. tungsten lamp, after being collimated by a plano— convex lens, passes through the sample solution, then through a narrow band interference filter with a transmission peak at 620 mu; it is detected by a barrier layer photocell. The output from the photo- cell is fed through a voltage dividing potentiometer to a recorder. A low value resistance in series with the voltage divider is electrically removed from the circuit by the same switch that starts the syringe drive motor. This effectively increases the input to the recorder by a small increment, causing a fiducial mark from which to measure the duration of the titration. The recording titrator affords a higher sensitivity than can be attained by visual titration. The effects of minor changes in titration conditions, not dis- cernible by visual titration, can readily be ascer- tained by the titrator. The precision of the motor- driven syringe, based on weight of solution delivered during varying distances of chart travel, was better than one part in two thousand. REAGENTS FOR TITRATION OF ALUMINA Alumina standard solution: 1.00 mg A1203 per ml in 2 percent hydrochloric acid. EDTA solution: 0.0100 M. Phenolphthalein solution; 0.1 percent in ethyl alcohol. Ammonia solution: 1 + 1 (v + v). Acetate bufl'er: 140 g sodium acetate and 60 ml acetic acid (conc.) per liter. Tiron solution: 2 percent in water. Ferric chloride solution: 0.2 mg iron per ml in water. PROCEDURE In a 400 ml beaker, treat a sample solution containing no more than 2.0 mg alumina as follows: Add 10.00 ml EDTA solution. Using several drops phe- nolphthalein solution as indicator, adjust the pH of the solu— tion to alkaline (pink) with ammonia. Add 25 ml of acetate buffer, 1 ml of Tiron solution, and sufficient hot water (80°— 90°C) to make a total volume of 300 ml. Titrate excess EDTA with ferric chloride solution. . GEOLOGICAL SURVEY RESEARCH 1961 STANDARDIZATION PROCEDURE AND CALCULATION Titrate three solutions containing (1) 0 mg, (2) 1.00 mg, and (3) 2.00 mg of alumina by the same procedure used for the samples. The titer of solution (1) furnishes the base value for 10.00 m] of EDTA solution. Subtract titer (2) from titer (1); this is the equivalent titer for 1.00 mg of alumina. Sub- tract titer (3) from titer (1) ; this is the equivalent titer for 2.00 mg of alumina. Calculate the titration factor by dividing the mg of alumina in solutions (2) and (3) by their respective equivalent titers. Subtract the titers of each of the sample solutions from the titer of solution ( 1). The net titer repre- sents the EDTA complexed by alumina in each solution. Calculate the percent A1203 as follows: titration factor X net titer x 100 percent A1203 : mg sample DISCUSSION The intermediate stability constant of the alumi- num-EDTA complex (log K=16.1) allows the use of a rather low pH (3.7) for the titration. This precludes interference by elements such as the alka- lies and alkaline earths, which are complexed at high pH only. However, this still leaves a major portion of the elements in the periodic table free to interfere by consuming EDTA. These elements must be separated if they are present in significant concentration. Among the anions, perchlorate interferes with the end point. Its effect in moderate concentration however, can be overcome by the addition of sodium sulfate. Phosphates must be absent. The method has thus far been applied to the determination of aluminain chromite and chrome ore. A mercury cathode electrolysis was used to separate chromium, iron, and nickel; a cupferron separation was used to separate titanium and vanad- ium when present in significant concentrations. Excess cupferron had to be destroyed completely with sulfuric and nitric acids before proceeding with the titration. The results given by the titration procedure were in good agreement with results ob- tained by a colorimetric procedure. Good agreement with the certified analyses was obtained in the analysis of standard samples of chrome ore. REFERENCES Haberli, E., 1954, A method for the titrimetric determination of iron in blood by means of complexon: Experientia, v. 10, p. 34—35. SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 Manning, D. L., Meyer, A. 8., Jr., and White, J. C., 1955, The compleximetric titration of zirconium based on the use of ferric iron as the titrant and Tiron as the indicator: U.S. Atomic Energy Commission ORNL—1950, 15 p. Milner, G. W. C., and Woodhead, J. L., 1954, The volumetric determination of aluminum in non—ferrous alloys: An- alyst, v. 79, p. 363—367. Patrovsky, V., and Huka, M., 1957, Complexometric titration l ’5? 143. B—331 XXI. Volumetric determination of iron, aluminum, and titanium in silicates: Coll. Czechoslov. Chem. 'Commun., v. 22, p. 37—42. Shapiro, L., and Brannock, W. W., 1955, Automatic photo- metric titrations of calcium and magnesium in carbonate rocks: Anal. Chemistry, v. 45, p. 725—728. Suk, V., and Malat, M., 1956, Pyrocatechol Violet; indicator for the, EDTA titration: Chemist-Analyst, v. 45, p. 61—62. DETERMINATION OF COPPER IN PLANT ASH WITH NEO-CUPROINE By CLAUDE HUFFMAN, JR., and DWIGHT L. SKINNER, Denver, Colo. Smith and McCurdy (1952) first investigated neo-cuproine (2,9—dimethyl—1, 10—phenanthroline) as a new and more specific chelating reagent for copper. Neo-cuproine reacts with a cuprous copper solution buffered with acetic acid to form a yellow- orange chelate extractable with water-immiscible alcohols at pH 7 or less. Since Smith and McCurdy’s report, many applications of neo-cuproine to de— terminations of copper in diverse materials have been made, for example, for copper in uranium ores (Skinner and Goss, oral communication), for copper- in germanium and silicon (Luke and Campbell, 1953), for copper in steels (Gahler, 1954), and for copper in titanium ore (Andrew and others, 1957). Thus the neo-cuproine reagent has become increas- ingly popular for the determination of copper in complex materials because of its unique specificity, stability, and sensitivity with copper. The method described here is an application of neo—cuproine to the determination of copper in plant ash. In develop- ing this method analyses were made of plant samples collected by F. J. Kleinhampl and field party from the following areas: Circle Cliffs, Garfield County, Utah; Grants district, McKinley County, N. Mex.; and Elk Ridge, San Juan County, Utah. REAGENTS AND EQUIPMENT Neo-cuproine solution. 1.085 g neo-cuproine is dissolved in 333 ml ethyl alcohol and diluted to 500 ml with water. Sodium citrate solution. 3 percent (w/v) solution in water. Sodium acetate solution. 20 percent (w/v) solution in water. n-hexyl alcohol, Eastman practical grade. This reagent can be reused after recovery by distillation. Hydroxylamine sulfate solution: 1 percent (w/v) solution in water, freshly prepared. Sodium hydroxide solution. 40 percent (w/v) in water. Standard copper solution. Stock solution 1 ml : 0.1 mg‘ Cu. Dissolve 0.3929 g of clear unflioresced crystals of CuSoi-SHZO in water, add 10 ml of hydrochloric acid and dilute one liter. Dilute solution 1 ml : 0.005 mg Cu. Dilute 50 ml of the stock solution to one liter with water. Absorption cells, matched, 1 cm. Beckman D. U. spectrophotometer. PREPARATION OF SAMPLE Dry and grind the plant material. Ash off 10 g of the ground vegetation at 550°C in a tared porcelain dish. Calculate the ash content. Thor- oughly mix the ash and reserve for analysis. PROCEDURE Accurately weigh about 100 mg of plant ash and transfer to a test tube (16 by 150 mm). Add 5 ml (1+4) hydrochloric acid and boil for one minute. Filter the solution through a retentive 9 cm filter paper into a 60 ml separatory funnel. Wash the residue four times with demineralized water. Add 5 ml of 3 percent sodium citrate solution to the filtered solution to complex the iron, then add 5 ml of 20 percent sodium acetate solution. Mix thoroughly, Add 5 ml of freshly prepared one percent hydroxyla- mine sulfate solution to reduce the cupric ion; adjust the solution to pH 5 with approximately 10 drops of 40 percent sodium hydroxide solution, and mix again. Add 4 ml of neo-cuproine solution and mix the contents of the funnel again. Add 10.0 ml of n-hexyl alcohol, stopper the separatory funnel and shake for 30 seconds. Allow the solution to stand for 5 minutes until the two immiscible solutions separate. Drain the aqueous layer and discard. B—332 Draw off a portion of the n-hexyl alcohol into a 1-cm cell and measure the absorbance with the spectro- photometer at 454,11, using a reagent blank carried through the entire procedure as a reference. STANDARDIZATION Portions of the standard solution containing 1, 3, 5, 10, 20, 30, 40 micrograms copper and one reference solution (reagent blank) Were carried through the entire procedure to establish a working curve. A plot of data from the standards above gives a satisfactory working range of 10 to 400 parts per million copper based on a 100—milligram sample of plant ash. REMARKS The neo-cuproine reagent is unique because it is specific for copper (Smith and McCurdy, 1952). The absence of interference by 56 metal ions at the 50—microgram level was shown by Luke and Camp- bell (1953). Tests for interference from 15 mg amounts of iron (III), aluminum, chromium (III), manganese (II), molybdenum (VI), and vanadium (IV), showed that they could be tolerated except for the chromium. Only about 2 mg of chromium can be tolerated (Andrew and others, 1957). The interference from anions can be significant because they form a tighter complex with copper than does neo-cuproine. Gahler (1954) has shown that trace amounts of cyanide, sulfide, and large amounts of phosphate must be removed to prevent their serious interference. No interference from chromium or phosphate occurs in the analysis of plant ash be- TABLE 1,—Summa7‘y of 82 plant samples used in the precision study Number . Average Copper (ppm) of as Plant species samples (percent) Range Average Juniper ................. 35 5.3 15—120 60 Pinon pine .............. 38 3 . 3 50—200 125 l’onderosa pine .......... 9 3 .0 65—150 108 GEOLOGICAL SURVEY RESEARCH 1961 TABLE 2.—Comparison of copper values determined by the neo-cuproine method and the biquinoline method [Analysts: neo-cuproine method, Claude Huffman, Jr.; biquinoline method, J. H. McCarthy] Copper in ash (ppm) Ash Sample (percent) Neo—cuproine Biquinoline Difierence 236762 ........... 8. 6 15 15 none 236763 ........... 4 . 8 75 80 —5 236764 ........... 5 . 7 30 25 + 5 236765 ........... 6 . 0 65 55 +10 236766 ........... 5. 1 3O 25 +5 236767 ........... 2 . Q 90 80 +10 Average .................... 51 47 6 cause the concentration of both elements is well below the interference levels established by the above authors. The precision of the determination of copper by the method described was calculated from paired data (Youden, 1951, p. 17) using replicated deter- minations on 82 samples of plant ash. The standard deviation of the determination is 9.6 ppm copper. The 82 samples used in the precision study consisted of branch tips from 35 juniper, 38 pifion pine, and 9 ponderosa pine. A summary of the 82 samples is shown in table 1. Table 2 compares the neo-cuproine method and the biquinoline method for the determination of copper in six plant ash samples. The agreement be- tween methods is about the same as the standard deviation of the determination. REFERENCES Andrew, J. F. Goulstone, A. B., and Deacutis, A. A., 1957, Spectrophotometric determination of copper in titanium: Anal. Chemistry, v. 29, p. 750—753. Gahler, A. R., 1954, Colorimetric determination of copper with neo-cuproine: Anal. Chemistry, v. 26, p. 577—578. Luke, C. L., and Campbell, M. E., 1953, Determination of impurities in germanium and silicon: Anal. Chemistry, v. 25, p. 1588—1593. Smith, G. F., and McCurdy, W. H., 1952, 2,9—dimethyl-1,10- phenanthroline, new specific in spectrophotometric de- termination of copper: Anal. Chemistry, V. 24, p. 371—373. Youden, W. J., 1951, Statistical methods for chemists: New York, John Wiley and Sons, Inc., p. 125. 5a SHORT PAPERS IN THE GEOLOGIC AND HYDROLOGIC SCIENCES, ARTICLES 1-146 144. B—33‘3 DIRECT-READING SPECTROMETRIC TECHNIQUE FOR DETERMINING MAJOR CONSTITUENTS IN NATURAL WATER - By JOSEPH HAFFTY and A. W. HELZ, Washington, D. C. Methods used by the Geological Survey for deter- mining major cations and silica in natural water entail in most instances five separate determinations employing titrimetric, spectrophotometric, and flame-photometric procedures. The use of optical emission spectrography with multiplier phototubes to measure the radiant energy of the spectral lines can quickly establish the concentrations of the major constituents in one operation. The procedure is simple in that no complicated preparation of sample or standards is necessary. It is designed to deter- mine the elements and compounds listed on table 1 in the ranges of concentration indicated. A specto- graphic-residue method for determining minor , elements in waters has been described previously (Haffty, 1960). Potassium was not included in the list of elements determined because a red-sensitive tube for measur- ing the very sensitive 7800 A (Angstrom units) line ‘ was not available. However, the writers feel that no difl‘iculty would be encountered if this element were to be determined, as the behavior of potassium in the spark is analogous to that of sodium. The present work was exploratory, and was done on a spectrometer set up specifically for the analysis of major elements of rocks rather than natural waters. Standard solutions were prepared as follows: Ca1- cium carbonate was dissolved in dilute nitric acid; sodium and potassium were added as the chlorides; magnesium added as the oxide was dissolved by addition of sulfuric acid; and silica was introduced by boiling commercial silica gel in distilled water, filtering, diluting the filtrate slightly and reboiling for a total time of four hours. All of the above substances, except silica gel, were of “specpure” grade. R. O. Fournier prepared the silica solution, and Leonard Shapiro and J. J. Rowe analyzed it. TABLE 1.—Spectrum lines and concentration ranges Wavelength Concentration range Element or compound (A) (parts per million) Calcium ...................... 3179.33 3 to 316 Sodium ....................... 5889.95 1 to 316 Magnesium ................... 2802.70 0.3 to 100 Silica ......................... 2881.58 3 to 31.6 Lithium ...................... 3232.61 Reference line Mercury ...................... 5460,74 Monitor line J. I. Dinnin made flame-photometric determinations for calcium and sodium in the water samples tested. The procedure consists of mixing 9 parts by 1000 _ 100 : m .- 0 >— E _ D _ < Lu C: _ .J <_( ._ Q 10 : 1 IIIII I IIIIIIII I IIIIII 0.1 1.0 10 CONCENTRATION IN ORIGINAL SOLUTION. IN PARTS PER MILLION 1000 _ 100 U) (D E D ‘1 “J 0: .1 S Q ‘ 10 : 1 IIIIIIIII IJLIIIIII I IIIIIII 1 10 100 1000 CONCENTRATION IN ORIGINAL SOLUTION, IN PARTS PER MILLION FIGURE 144.1.—Working curves used for obtaining concentra- tions of major constituents in natural water. B—334 volume of water sample with 1 part of a lithium solution, prepared by dissolving lithium carbonate in dilute nitric acid. Lithium is used as the reference element, and in the final mixture it is equivalent to 1 gram per liter. The mixture is then poured into a porcelain boat and excited directly using the ro- tating disk method. The standards are treated in the same way as the unknown samples. The radiant energy is measured by multiplier phototubes placed in back of slits so located as to select lines of wave- lengths indicated in table 1. The output of the multiplier phototubes activate amplifiers which record the intensity of light on the tubes. The length of a “run” is determined by the output of the photo- tube for lithium. The response is adjusted to give a 60-second run by setting the dc (direct current) supply voltage for the “lithium” multiplier photo- tube. The analytical range for the elements sought is subsequently adjusted by setting the correspond- ing dc supply voltages. Working curves are con- structed from the standard solutions by plotting parts per million of the element or compound versus the dial readings on log-log paper. Examples of such curves are shown on figure 144.1. The concen- trations of the elements in the unknown samples are read from the working curves. The excitation source is a low-voltage under- damped repetitive discharge having a sparklike character. The circuit parameters of a satisfactory unit used for this work are: capacitance, 14 micro- farads; inductance, residual; resistance, residual; discharge-point control, 300; and output voltage, 145. GEOLOGICAL SURVEY RESEARCH 1961 940. A 3-mm spark gap is maintained between an upper pointed graphite electrode 14-inch in diameter and a lower graphite disk, 1/2-inch in diameter, which is partly immersed in the sample and rotated at a speed of 10 rpm. Sparse comparative data with chemical and flame- photometric methods indicate that acceptable agree- ment has been obtained for the elements determined in the lower range of concentrations. However, the Calcium line seems to be enhanced in higher con- centrations (about 35 ppm and higher). The work- ing curve for sodium shows that self-reversal of the 5890A line takes place, but acceptable agree- ment with flame-photometric results was realized in the range 2 to 10 ppm. Good comparisons were obtained for magnesium in the range 2 to 25 ppm and silica in the range 3 to 30 ppm. Dilution of the sample may solve the difliculties indicated above for calcium and sodium. However, this requires additional operations that defeat the purpose of the procedure. Further work may dis- close that there are more suitable additives to the solutions, or that a selection of other spectral lines is necessary to determine accurately the concentra- tions of these elements. Our experience indicates that within a few minutes the procedure will pro- vide determinations of the major constituents in natural waters. REFERENCE Haffty, Joseph, 1960 Residue method for common minor ele- ments: U.S. Geo]. Survey Water-Supply Paper 1540—A. ’X RAPID QUANTITATIVE ESTIMATES OF QUARTZ AND TOTAL IRON IN SILICATE ROCKS BY X-RAY DIFFRACTION By D. B. TATLOCK, Menlo Park, Calif. The relationships between diffraction, absorption, fluorescence, and density allow for rapid and rea- sonably accurate quantitative estimates of quartz and total iron in most holocrystalline silicate rocks, both fresh and altered, from X-ray diffraction pat- terns of whole-rock powders. Diffraction analysis has proved indispensable in the study of crypto- crystalline metasomatized rocks not amenable to modal analysis by microscopic examination. N o attempt is made in this short paper to present de- tails of instrumentation or of sample preparation. The reproducibility of quartz peak heights in quantitative diffraction work has been well demon- strated by many investigators (Klug and Alexander, 1954, and Weiskirchner, 1960). Only a few (Black, 1953, and v. Engelhardt and Haussiihl, 1960), how- SHORT PAPERS IN THE GEOLOGIC AND 80 l l l l I l 70,— _ 50— Matrix less (Fe203+Fe O) — 40— — QUARTZ MASS ABSORBPTION COEFFICIENTS (CuKd1.5418A) I l | l I l 0 CALC-ALK CALC-ALK DACITE LATITE ANDESITE NORMAL RHYOLITE TRACHYTE / THOLEIITIC BASALT FIGURE 145.1.—Mass absorption coefficients of matrices of average igneous rocks with and without (Fegoa + FeO) and exclusive of normative quartz. ever, have applied diffraction to modal analysis of the common silicate rocks on a mass production basis, owing to the seemingly adverse effects of absorption and fluorescence. In comparing diffrac- tion patterns of quartz-bearing whole-rock powders ranging from felsic to mafic in composition, absorp- tion effects are present that usually prevent a direct comparison of the quartz peak heights (Leroux, Lennox, and Kay, 1953). Specifically, when a mix- ture contains both a weak and a strong absorber, peaks of the weakly absorbing component appear weaker, and those of the strongly absorbing com- ponent stronger, than expected from a linear rela- tionship for each component (Klug and Alexander, 1953, p. 411). In determining the quartz content of a whole-rock powder, the powder may be regarded as consisting of just two components, the quartz, and the sum of the other minerals which may be- designated the matrix. Figure 145.1 shows that the mass absorption coefficients of the matrix portion of average igneous rocks (Nockolds, 1954), exclusive of the iron oxides and normative quartz, are nearly constant, ranging from 43 for rhyolite to 48 for basalt. With iron oxides included in the matrix, however, the mass absorption coefl‘icients range from 49 for rhyolite to 74 for basalt. Hence, iron is shown to be the element chiefly responsible for appreciable differences in absorption in the matrix component of the common silicate rocks. Iron, also, is the only relatively abundant com- mon rock-forming element whose fluorescence under HYDROLOGIC SCIENCES, ARTICLES 1-146 B—335 copper radiation affects appreciable differences in background. The greater the iron content of a whole-rock powder, the greater the background in- tensity of its diffraction pattern. This relation- ship allows for an estimation of the total iron in a sample by reading the background at a given angle 20 after the diffraction unit has been cali- brated. In figure 145.2 the total iron, calculated from chemical analyses of metasomatized rhyolitic and andesitic rocks and Franciscan graywackes, has been plotted against background intensities at the 4.26A quartz line as recorded on diffraction patterns of splits of the chemically analyzed powders. The background intensity is the average of mea- surements on both sides of the selected line (Carl, 1947). Such a curve can easily be extended for rapid and reasonably accurate analysis of low- grade iron ores by preparing mixtures of quartz and hematite or magnetite; accuracy is Within 10 per- cent of the amount of iron present in concentrations greater than 20 percent. Referring again to figure 145.1, the slightly strongly absorptive character of the matrix com- ponent (less iron) in mafic rocks relative to felsic rocks, and its consequent depressant effect on quartz BACKGROUND INTENSITY AT 4.26 A (20.8” 29) 10 I I 1 l l 1 0 1 2 3 4 5' 6 7 TOTAL IRON-WEIGHT PERCENT FIGURE 145.2.—Total iron, calculated from chemically an-- alyzed rocks, plotted against backgrotmd intensity of 20.8°20 (CuKa; nickel filter). 7O 60 ‘50 40 30 BACKGROUND AT 4.26 A (CuKIl‘I ‘\20 lO PEAK HEIGHT ABOVE BACKGROUND 4.26 A (208° 26) o ’10 20 30 40 50 60 7o 80 QUARTZ,WE|GHT PERCENT FIGURE 145.3.—Peak height" curves and corresponding back- ground curves for quartz mixed with materials having different mass absorption coefficients resulting chiefly from differences in iron content. Construction of inter— polation curve is illustrated. peak intensities, is roughly compensated by density differences in quartz (2.65) and total matrix (basalt 2.97). This is because of the greater volume percent (and hence, greater percent of the surface exposed to radiation) of quartz relative to its weight percent when mixed with a denser material. This density- absorption compensation permits an almost direct comparison of quartz peak intensities regardless of the matrix—except for the effects of iron. To compensate for the absorption and fluorescence effects of iron when analyzing for quartz, four peak height curves and their corresponding background curves were established from prepared powders of quartz mixed, in order of increasing absorptive strengths, with (a) natural pinite (muscovite), (b) biotite-actinolite greenstone, (c) chlorite, and (d) magnetite; the letters correspond with the curve- sets in figure 145.3. The curves are based on the diffraction intensity of copper radiation from the (100) plane of quartz (Weiskirchner, 1960) and the background intensity in the immediate Vicinity of the same line (4.26A or 20.8°20) at a scanning speed of 2° 20 per minute. Slower scanning speeds may be used, but with only slightly better accuracy. Differences in the mass absorption coefficients of matrices have been shown to be chiefly a function of iron content, and iron content is expressed by background intensity. As iron content increases, background intensity increases, and so, too, does GEOLOGICAL SURVEY RESEARCH 1961 sofi#r|e» 80 Q I 80° 70~ I I 70 s I ' I I < eo~ l f I / 60 ’s‘ S I x Z I‘ ’ I / g 50—777T--—L—A——/->—l—— so: 3 i ll / / / 2 :2 4 _ I / /l / / / / I40 '2 2 O / / f / / / / / D E l / Y/ / / // / / g > R I / f / O 830 / / / f/ / / / / 30% i / / / / / I/ /// /// 5 g 20~ ,/ / // //// / ///,//V;/~