A io S we e .ie. A) General Geology of Death Valley California GEOLOGICAL-_ SURVEY PROFESSIONAL PAX PER -494 This volume was published in separate chapters A and B UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director £4. .:: SCIENCES LIBRARY f APPC CONTENTS [Letters designate the separately published chapters] (A) Stratigraphy and structure, Death Valley, California, by Charles B. Hunt and others. (B) Hydrologic basin, Death Valley, California, by Charles B. Hunt, T. W. Robinson, Walter A. Bowles, and A. L. Washburn. IIT 716 sls stage 7 DAY | § Stratigraphy and Structure Death Valley, California LQS GEOLOGICAL SURVEYgPROFESSIONAL PAPER 494-A - J. Stratigraphy and Structure Death Valley, California By CHARLES B. HUNT ard DON R. MABEY GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA GEOLOGICAL SURVEY PROFESSIONAL PAPER 494-A Stratigraphy and structural geology, both of the surficial deposits and bedrock. _ Two companion reports describe the hydrology, saltpan, and plant ecology, UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1966 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director } EART! SCIENCES LIBRARY For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page tL... ancl LLL ol ease n eek cae neo sA Al Introduction, by Charles B. 3 Location and description of the valley_____________ 3 Mapping of the 7. 0 8 Stratigraphy, by Charles B. Hunt_____________________ 9 Precambrian _c: 11 Rocks of the crystalline basement-___________ 11 Pahrump 0 12 Crystal Spring Formation-___--__-________ 13 Beck Spring Dolomite___________________ 14 Kingston Peak(?) Formation--__________ 15 Noonday 16 Johnnie 17 Siiling 20 Cambrian 22 Wood Canyon Formation ___.___________.____ 22 Zabriskic .._... -__: 24 Carrara 25 Bonanza King 27 Nopah Formation....s....--_-_...l..:l i>.>; 29 Ordovician 33 Pogonip 33 Eureka 35 Bly Springs 36 \y Silurian and Devonian Systems-Hidden Valley Dolomite: n.}: 0.0 (.l 38 « Devonian System-Lost Burro Formation.-..---__ 40 Mississippian System-Tin Mountain Limestone and younger 43 Mississippian and Pennsylvanian(?) Systems-Rest Spring Shale. Lanus ._, 44 Pennsylvanian and Permian Systems-Formations at east foot of Tucki Mountain__.______________. 46 irringsic 01 c_}. 50 Cretaceous or Tertiary Systems___________________ 50 Granitic 50 Chaotic complex along Amargosa thrust fault. 51 onan 51 Formations in the Black 51 Formations around Cottonball 54 Oligocene(?) formations__________________ 54 Miocene(?) formations.__________________ 87 Pliocene 59 Pliocene and Pleistocene(?) deposits-Fu- neral 63 Quaternary co.. 64 Pleistocene 64 Wo. 2 c .ll 64 l 69 Lake 1... lull 69 Valley Aill:1 be. _i T2 Stratigraphy, by Charles B. Hunt-Continued Quaternary System-Continued Pleistocene(?) and Recent(?) Sand and silt in the playa_______________. No.::8 gravels L Deposits of travertine and caliche cement in gravel=r:l. _. _ecaks cally Recent ii ccc cL. Luts CLOS Shoreline features of the Recent lakes.... Older salines... Massive rock salt___________________ Rough silty rock salt___________._ ___. Smooth silty rock salt_____..---_--_. Massive Saline deposits forming at present_____--__ Flood-plain deposits____________._.____ Marsh deposites...._..:-.._........:.. No.'Agravel-c_s-i-tr.cl.t....il.llu..e. Alluvium along Amargosa River and Salt 12. en e on n e ahem oak Dune sand-. =z... S2. II- Heal Siwa Archeology of the deposits_____--__--___._ Physiography of the fans________________._ -_. Desert varnish. _ 001 .d Erosion and sedimentation.---------------------- Damage to roads and flood-control ditches and other features in 25 years-. ______________ Damage to trails about 50 years old_____-____._ Damage to prehistoric archeological features. . _ Damage to Recent fault scarp along foot of Black Weathering, erosion, and sedimentation on Quater- nary deposits.... cls nul soe Structural Geology, by Charlee B. Hunt and Don R. -We ances soe o Structural setting of Death Valley____________-__--- Recent and late Pleistocene structural geology.. Structural features of the saltpan and gravel Tans. o N na naar e ols a an a an a onan gie Recent tilting of the saltpan-___-__-_____. Recent anticlines and faults affecting the ili as Faults and folds on the gravel Valley fill.____.. MEAC oue oh ea s a lae a Gravity Magnetic Changes in the altitudes of bench marks___--_. Seletic ACOVIVIOY E L 22222. are eer n- oo kah ~s Tiltmeter measurements, by Gordon W. Greene. e ened ok III 87. 90 93 93 95 96 97 97 97 98 100 100 100 100 103 107 107 108 110 110 112 112 112 IV Structural Geology-Continued Structural Geology-Continued Recent and late Pleistocene structural geology-Con. Structure of Precambrian and Paleozoic rocks.. -- Tiltmeter measurements-Continued Page Tucki: Mountain Relation between tilting movements and Tucki Mountain : j seismic activity:. csc l_ A1l4 Southern part of the Panamint Range ________ Early Pleistocene structural features. 114 Black Mountains fenster_____________________ Late Tertiary structural features_.________________ 116 Funeral Mountains fenster and Funeral Moun- Miocene(?) and early Tertiary structural features.__ _ 118 tains cue cue Granitic intrusions: ll .l 120 Southern Grapevine Mountains_______________ Granite at 123 Origin of the structural features. 00. Granite at Hanaupah 126 Summary of the structural features Chaotic complex along the Amargosa thrust.... 129 | _ cilirum ane oue Indicated granitic rock under the Panamint Range.. - 139 | Index. ILLUSTRATIONS PraTE 1. General geologic map of Death Valley, In pocket 2. Maps illustrating some differences in dissection of gravel fans along the east foot of the ranamint'Rahge=:-~.5.-......... cree issa ute canned canna na cence s In pocket 3. Tectonic diagram and Bouger gravity map, Death Valley________________________ In pocket Page Figur® 1. Relation of Death Valley to the southern Great Basin, northern Mojave Desert, and Sicrra n-. ed. L000. Lc nee ne nene annals an. tn a A4 2. Block diagram of Death Valley.. cr CCl Lelo ove iene 5 3. View west across Death Valley to the Panamin't Range-_____________________________ 6 4. View southeast across Death Valley to the south end of the saltpan and mouth of the Amar- RMiver.c:sle i.. ._} cull {200 ool Menai one ca ocr views 7. 5. View northeast across Death Valley to the Black Mountains and Funeral Mountains.. 8 6. Diagram illustrating distribution and possible structural relationship of the three for- mations of the Pahrump Series in the Panamint Range 13 7. View of Crystal Spring lll. lo ee 14 8. Micrographs of quartzite and dolomite in Crystal Spring Formation. 15 9. Structures suggestive of Scolithus tubes in Noonday Dolomite.___________-________---.- 17 10, Micrographs of Noonday CLO IMS 18 11. View of Johunie Formation.. lel ler en eweinnene nec ane amend 19 12. Micrographs of rock types in Johnnie Formation._._______.__LLL_________L_.__L_____ 20 19, View of Stirling f fi L L_ ire coud 21 14; Micrograph of Stirling _. cl. [LL LLL LLC Avo den 21 15. View of interbedded shale, quartzite, and dolomite in upper part of Wood Canyon For- lee e o n Lea ida en rn cannaricae cal ans nig ack cue ne 23 16. Micrographs of shale and quartzite from Wood Canyon Formation-_______----_---_----- 24 17. Micrograph of Zabriskie l 24 18. View of Zabriskie Quartzite, Carrara Formation, and base of Bonanza King Formation.. 27 19. Fragments of bioclastic "trilobite trash" bed typical of lower part of Carrara Formation. 28 20., Micrographs of Cambrian carbonate roeks_________L__________L_LLLLLLLL_LLLL___Q_Q 28 21. Linguloid brachiopods and trilobites from shaly zone near the middle of the Bonanza King sects "ctf _ lo a uae isc eca n rae canes 29 22. Thin-bedded limestone member near the middle of the Bonanza King Formation.... 30 23. Bioclastic bed with fragments of trilobites and brachiopods from base of Nopah Formation. 31 24. View of Pogonip Group in Trail 33 25. Micrographs of Ordovician dolomite and quartzite. ____________________________----- 34 26. Large gastropods in dolomite in upper part of Pogonip Group.-_______________-_-_------ 35 27. View of Eureka Quartzite and overlying Ely Springs Dolomite at mouth of Little Bridge Canyon oct no n on po ar n rd oic iene ao aa ea nin tare, «aba 37 28. View of Ordovician, Silurian, and Devonian formations on south side of Tucki Mountain. 39 29. Micrograph of Lost Burro ee as- ceases 40 30. Stromatoporoid and Amphipora(?) beds, Lost Burro Formation_________________-_-_---- 42 S1. Limestone containing 42 32. Diagrammatic sections of Devonian and Mississippian syringoporoid corals. ____--_----- 48 CONTENTS Page A141 142 143 143 147 147 150 150 152 153 157 Fraur® 33. 34. 35. 36. CONTENTS Micrographs of limestone from Tin Mountain Limestone and unnamed younger Mis- sissippian Golfball-like nodules of dark chert in Rest Spring Shale. ________________________-____-- Micrograph of limestone from Rest Spring SRAIG-__-__-__-____------------------------ View of thin-bedded limestone and dolomite near base of unnamed formation of Pennsyl- vanian age, east foot of Tucki . Micrograph of limestone from unnamed formation of Pennsylvanian age. _..._______-_. . Geologic map of Badwater turtleback and adjacent AreAS- ______-____-__--------------- . Micrographs of thin sections of felsite and explosion breccia in Artist Drive Formation.... . Sketch map of Tertiary formations around Cottonball Basin-._._-____________-_--__--_.- . View of fractured cobble conglomerate in the Titus Canyon(?) Formation-_____-------- . Micrograph of thin section of greenish clay from Titus Canyon(?) Formation-___------- . Micrographs of thin sections of four sedimentary rocks from Miocene(?) formations.... . View of Furnace Creek Formation at north end of Black Mountains--.-.--------------- . Micrographs of thin sections of playa deposits in the Furnace Creek Formation-.....---- . Gravel fill in former channel of Furnace Creek Wash-___-________________---_-------- . Escarpment along front of north end of Black Mountains--_-___----_----------------- . Map and profile across mudflows on Starvation Canyon fan c e e aaa aie m ile . Boulders disintegrating to slabs and flakes ; Desert pavement. :....__.i_.-.: cl. rl . Desert pavement interrupted by . Gravel bar of Lake . View along narrow terraces interpreted as sears of strand lines________________-------- . ~Wind-faceted cobbles: 2. L. ide- ant aes wine . No. 2 gravel displaced by fault that is overlapped by No. 3 gravel____________-------- . Travertine deposit along Furnace Creek WASR__________-_-___________-_-----_--------- . View of Trail Canyon fan showing lower limit of desert varnish._______-_______--------- . Shoreline of Recent lake in cove north of West Side Borax Camp-__________---------- .' Shoreline cut in alluvial bank... AII. II- LOU ieee ne saa aes . Shoreline at foot of Artists Drive fault . Shoreline at foot of fan north of Coffin asp . Contrast between No. 4 and No. 8 . No. 2 gravel overlapped by fan of No. 4 ______________________-__----------- . Diagram illustrating downfan shift in position and overlap of younger gravels on older clt Q.. l. ccc cl cc .C iL ca . Map illustrating differences in drainage pattern on the older and younger gravels_____.- . Fan patterns at the foot of the Black Mountains and the Panamint Range-___--------- . Sections illustrating depth of fill in Death Valley----------------------------------- . Map showing the Death Valley subsection of the Great Basin-___________-_-___-------- . Map showing seismic epicenters in southwestern United . Bouguer gravity-anomaly map of southwestern United States._ _______-_--_----------- . Sketch map showing principal Quaternary structural features in Death Valley.->..---s.. . Recent fault searp at foot of Black . Map of Indian sites along the escarpment of a Recent fault at foot of Black Mountains. -- . Map showing drainage deflected at the projected axes of turtlebacks in the Black Moun- tains... oll silrin c I pede c in aa aa an sn win's» sale amie nle nle n aa ae a oe a mn a o . Oblique aerial view of the Salt Creek . Escarpments of late Pleistocene and Recent faults west of Bhortys.Well..._:_.___-._.-- . Hanging valleys at front of Black . Hanging valley at Gower Gulch at front of Black Mountains ___________-_------------ . Section from Funeral Mountains southwestward across Texas Spring syncline and Black Mountains -c. 2 clr PI L een ue anneals -be ec eusps ste aul . View along southwest flank of anticline at Mustard Canyon Hills-___---_-------------- . Diagram illustrating gravity anomaly produced by & prism.__.-_---------------------- . Gravity and inferred bedrock profile across Badwater Basin-_-.----------------------* . Aeromagnetic profiles across Death Valley.--.--_______________c__-c----__---------- . Relative changes in altitudes of bench marks in Death Valley between level surveys in 1907 and 1933 and in . Diagrams showing tilting observed in the Death Valley area_______-------------------- . Rection of Tucki Mountain.: ban lene alas an . Section of the Copper Canyon turtleback . Diagrammatic section illustrating probable thinning and offlap of Tertiary and Quater- nary formations from the Black Mountains northeastward to the Texas Spring syncline. Page A45 45 46 47 48 52 53 55 56 57 58 60 62 65 66 67 68 68 68 69 70 T7 T8 78 80 80 81 81 82 85 86 86 88 89 94 98 99 100 100 101 101 102 103 104 105 106 106 107 108 109 111 113 115 118 119 VI Fraur® 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117. 118. 119. 120. 1. Precambrian, Paleozoic, and Triassic formations exposed in the Death Valley area CONTENTS Fence diagram illustrating inferred shape of granitic intrusion at Hanaupah Canyon Micrographs of thin sections of granitic instrusion at Hanaupah Canyon Map of Amargosa thrust complex along east foot of Panamint Range View of dike swarm in Amargosa thrust :L. __ lao . View of chaoslike formation in Amargosa thrust complex View of augen gneiss in Amargosa thrust complex_________________L_________________ Specimen of augen gneiss from Amargosa thrust Diagrammatic section illustrating flattening of foliation of augen gneiss eastward from dikes: eeu c ere ce sea- areas ced oan aol ios cl ea nein een L d Granitized metasediment and incompletely replaced metasediment in Amargosa thrust leis esl eon cane elena cee cubes tran an cece cen ce Micrograph of thin section of granitic rock in Amargosa thrust complex Felsite plug in granité in Amargosa thrust complex_________LLL________L___LLLLL_____ Micrographs of thin sections of volcanic rocks in Amargosa thrust complex Sketch :of Copper Canyon turtleback...: lol c cll lle cor rel Section of Black Mountains, Death Valley, and Panamint Range showing supposed extent of Amargosa thrust and relations of granitic intrusions and volcanism to it Isometric fence diagram of Tucki Mountain klippec_________________________________ Topographic and geologic map of exhumed surface of Trellis Canyon Diagram illustrating difference between actual dip and effective dip in series of fault blocks. Fracture cleavage in shale member of the Stirling Quartzite__________________________ Burro Trail fault. View north from the divide north of Starvation Canyon Burro Trail fault. View south across Hanaupah Burro Trail fault. View north between Death Valley and Trail Canyons Burro Trail fault on south side of Trail ctl View north scross tear fault in Starvation .cc cle Turtleback fault surface marking Keane Wonder fault Section of west end of Funeral Mountains Section from Virgin Valley to Colorado Plateau showing low-angle faults TABLES 2-18. Trace elements in- - Precambrian metamorphic lll. . sl reuse lille tad an a AOrystal Spring Formation... ;. {inl Xl E s, . Kingston Peak(?) Formation . Noonday Dolomite . Johnnie Formation. w so -r o prc co ho 10.-Carrara e_ 11. Bonanza King Formation, Panamint Range 12. Nopah Formation. 4 19. Ordovician units, Panamint Range.. LL. aik 14. Devonian and younger Paleozole 15.) Voleanic rocks in the Artists Drive Area-... ens 16. Beds correlated with the Titus Canyon(?) Formation of Stock and Bode (1935) --- 17. 'Miocene(?) 'deposite: cen ._ co orl s 18. Furnace Creek Formatlon 20 Trace elements in spring-deposited travertine and in calcite vein in the Funeral Formation.. 133 134 135 185 136 138 139 139 142 143 144 145 146 146 147 148 149 149 150 151 TaBuE 21. 22. 28. 24. 25. 26. CONTENTS Page Semiquantitative spectrographic analyses of desert varnish.... Delco A91 Erosion, in 20 years, of road shoulder 6 inches high along old bladed road from Beatty Junction south along the foot of the gravel 95 Erosion of flood control embankments in 25 95 Erosion along old trails in the last half 96 Trace elements in the granites at Skidoo and at Hanaupah Canyon-____--_-----------.--- 121 140 Trace elements in the Amargosa thrust VII GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA STRATIGRAPHY AND STRUCTURE By Cnarurs B. Hux and Don R. Massy ABSTRACT Death Valley is in southeastern California at the south edge of the Great Basin. The valley and the mountains around it have been the site of three major geosynclines-one formed dur- ing late Precambrian time, another during the Paleozoic, and a third during the early part of the Mesozoic Era. During late Mesozoic and early Cenozoic time the southern Great Basin was part of a geanticline that was folded, thrust faulted, and invaded by granitic intrusions, and that shed sedi- ments to surrounding regions. Later in Cenozoic time the southern Great Basin, including Death Valley, became frag- mented, mostly by block faulting, into basins and ranges, and during this time sediments that were eroded from the ranges collected in the basins. The rocks exposed in Death Valley and the adjoining moun- tains aggregate more than 60,000 feet in thickness, which is only a little more than half the aggregate thickness formed dur- ing the geosynclinal and other episodes in this part of the Great Basin. The rocks that are missing probably once were present, but they have been removed 'by erosion (represented by uncon- formities) or are concealed by structural discontinuities. Precambrian rocks are in three major groups. The oldest, which are metamorphic rocks representing the crystalline base- ment complex, have a structural and topographic relief of more than 3,000 feet. Overlying the basement complex is the Pahrump Series, which comprises much younger and only slightly metamorphosed forma- tions that are mostly clastic sedimentary rocks, but they include some limestone and dolomite and some diabase. These forma- tions total at least 10,000 feet in thickness. They are not ex- posed one above the other in this area, and their stratigraphy is inferred from known relations elsewhere. Westward across the Panamint Range, each of the three formations of the series rests in turn on the metamorphic basement complex, probably as a result of thrust faulting rather than stratigraphic changes. The third and youngest group of rocks included in the Pre- cambrian are sedimentary formations, mostly clastic, but they include considerable dolomite and some limestone. These rocks are slightly less metamorphosed than those of the Pahrump Se- ries; the metamorphism is about the same-as that of the Cam- brian rocks. However, these formations lie below the Olenellus fauna, which is taken to mark the base of the Cambrian. Their thickness aggregates 7,000 feet. An unusually complete section of Paleozoic formation is ex- posed in Tucki Mountain where rocks ranging in age from Early Cambrian to Permian, and representing all the intervening sys- tems, are more than 20,000 feet thick. The Lower Cambrian formations are mostly clastic sedimentary rocks, but the rest of the Paleozoic formations are chiefly limestone and dolomite. The Permian rocks include much conglomerate or breccia de- rived from Paleozoic formations at least as old as Early De- vonian and as young as Late Pennsylvanian. Evidently there was considerable deformation during Permian time ; it may have begun in Pennsylvanian time. At the south end of the Panamint Range, only a mile outside the area being reported upon, Triassic formations total 8,000 feet thick. These formations are composed of volcanic and clastic sedimentary rocks, and represent a return to conditions like those of the Precambrian. Moreover, the thick remnants of the Triassic, like 'the thick remnants of the Precambrian Pahrump Series, are restricted to a northwest-trending belt ap- proxiately coinciding with the edge of the Sierra Nevada batholith. Two granitic intrusions that seem to be eastern satellites of the Sierra Nevada batholith lie within the mapped area. They are referred to as the granites at Hanaupah Canyon and Skidoo, and probably are floored intrusions that spread laterally along thrust faults and made the space they occupy by doming the rocks of the upper plates of the thrusts. The intrusions of the batholith in the Sierra Nevada are Late Jurassic and Cretaceous in age. The granitic intrusions in the Death Valley area are closely related to the volcanism, which is of middle Tertiary age and these granites are younger than the main part of the batholith. This raises a philosophical question as to how widely apart in time and space individual plutons can be and still be part of a composite batholith. Evidence for a close relationship between the granitic in- trusions and the volcanics in the Death Valley area is found along the east foot of the Panamint Range. There a complex of may kinds of igneous, metamorphic, and sedimentary rocks occurs along a thrust fault believed to be the westward ex- tension of the Amargosa thrust. Precambrian augen gneiss cut by a granitic intrusion and a swarm of still younger dikes, underlies the thrust fault. A similar augen gneiss and similar granitic intrusion underlie the Amargosa thrust at the Virgin Springs district 20 miles to the southeast across Death Valley. Zircons in the Precambrian rocks differ from those in the dikes ; the granite contains both kinds. Overlap of lavas and associated eruptives onto Paleozoic rocks of the Panamint Range shows that the eastward tilting of the Range occurred half before, and half after, the eruptives were deposited. That the volcanic rocks along the belt of the Amargosa thrust complex are Tertiary is indicated by the stratigraphy of the very similar volcanic rocks in the Tertiary formations along the east and north sides of Death Valley. Tertiary formations in the Black Mountains east of Death Valley are at least 12,000 feet thick. The older deposits, volcanics 5,000 feet thick in the Artists Drive area, are quite like those in the Amargosa thrust complex. They are faulted onto the Precambrian core of the mountains. - Northward these volcanics grade laterally into A1 "x AZ playa and other sedimentary deposits. They dip northward and thin under a syncline separating the Black and Funeral Mountains. Where the older formations rise again on the north flank of the syncline, at the base of the Funeral Mountains, they are very similar to the Titus Canyon Formation (Oligocene) of Stock and Bode (1935), and are tentatively correlated with it. In the trough of the syncline is the Furnace Creek Forma- tion of Pliocene age, which is capped by and intertongues with the late Pliocene and early Pleistocene(?) Funeral Formation. Between the outcrops of the Furnace Creek and Titus Canyon ( ?) Formations is a faulted belt of different-looking sedimentary de- posits which, on the basis of structural position, are assumed to be of an intermediate age and accordingly designated Mio- cene(?). The oldest deposits in Death Valley classed as Quaternary are cemented fan gravels included with the Funeral Forma- tion. In places the Funeral Formation is conformable on and intertongues with the playa deposits of the Furnace Creek For- mation of Pliocene age, but more commonly the Funeral rests with angular unconformity on the older rocks. The Funeral Formation has been displaced thousands of feet by faulting and tilting during the late stages in the structural development of Death Valley and the bordering mountains. Subsequent to most of that deformation huge gravel fans were built from the mountains to the floor of the valley. Some of these are 6 miles long and more than a thousand feet high. The oldest of these fan gravel deposits, referred to as the No. 2 gravel, still has a distinct fan form which the older Funeral Formation has lost because of deformation and erosion. Both the No. 2 gravel and Funeral Formation have smooth surfaces of desert pavement. Boulders and cobbles on these surfaces are deeply weathered and have disintegrated to produce a new mantle of angular rock fragments. The No. 2 gravel is surely late Pleistocene in age, but it may be pre-Wisconsin. Other deposits of late Pleistocene age include a debris ava- lanche at the front of the Black Mountains and some isolated poorly developed beach deposits of a late Pleistocene lake, which had a maximum depth of about 600 feet. The lake, though, was of brief duration and evidently its level fluctuated rapidly, so that beach deposits and other shore features are poorly developed as compared with those around other Pleisto- cene lake basins in the Great Basin. Younger gravels on the fans, referred to as No. 3, may in- clude some late Pleistocene deposits and certainly include some Recent deposits. Other deposits that may be of approximately this age are mounds of travertine at springs on the gravel fans. Some travertine, of course, is being deposited at present, but the oc- currence on these mounds of stone artifacts representing the earliest human occupation of the area indicates that the main parts of the mounds have considerable antiquity. The youngest gravel on the fans, the No. 4 gravel, is along the washes. 'These deposits are loose gravel composed of firm rocks without desert varnish. During the Recent, but probably during the 3 millenia preced- ing the Christian Era, lakes flooded the floor of Death Valley to a maximum depth of 30 feet. The salt deposits comprising the saltpan were formed as a result of this lake. The principal structural features of Quaternary age are (1) the north-south trough that is Death Valley and the bordering upfaulted mountain blocks; (2) the northwest- trending Furance Creek fault zone and the downwarp that extends along Furnace Creek and northwestward across the northern part of Death Valley; (3) the northwest-trending GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA Confidence Hills fault zone that extends into the south end of Death Valley; and (4) some features of Copper Canyon and Butte Valley. Deformation is going on at present, as indicated by measurable tilt at seven tiltmeter stations that have been established in the valley. The composition and extent of the Furnace Creek Formation of Pliocene age indicate that it was deposited in a narrow trough that extended southeastward from Mesquite Flat across the Salt Creek Hills and Cottonball Basin and along the Texas Spring syncline and north end of the Black Mountains. The plays in which the formation was deposited existed long enough to accumulate 5,000 feet of beds. Much or most of the uplift of the Black Mountains occurred after the Furnace Creek Formation was deposited because the formation dips 45° or more off the north end of the mountains. Gravity data, however, indicate that the formation probably thins northward under the Texas Spring syncline, and presum- ably the thinning is by offlap from the mountains. If so, part of the uplift of the Black Mountains occurred while the Fur- nace Creek Formation was being deposited. It is inferred that roughly 4,000 feet of uplift at the Black Mountains occurred while the Furnace Creek Formation was being deposited, that another 3,500 feet of uplift occurred during early Pleistocene time, and the last 2,500 feet of uplift occurred in late Pleisto- cene and Recent time. The Miocene(?) and older Tertiary formations exposed in fault blocks between 'the Funeral Mountains and the trough in which the Furnace Creek Formation was deposited are mostly coarse clastics that were derived from the Funeral Mountains. The mountains and the adjoining basin therefore were in exist- ence in mid-Tertiary time. The basins and ranges in this part of the Great Basin are at least as old as the Titus Canyon and Artist Drive Forma- tions, although the structural limits of those basins and ranges probably were different from the present ones. The structural history of the region during the earlier geanticlinal stage is obscure. The principal features are the westward-directed Amargosa thrust, the chaos that accom- panies it, the smoothly exhumed surfaces of the thrust faults locally known as turtlebacks, and the granitic intrusions that seem to have spread along the thrust faults. A short segment of the Amargosa thrust is exposed along the east foot of the Panamint Range. The lower plate there, com- posed of Precambrian metamorphic rocks, is cut by a granitic intrusion. The metamorphic rocks include an augen gneiss; locally the augen are collected into small pegmatitic masses that . grade into the dikes of Tertiary age that cut all the rocks in the lower plate. Part of the metamorphism of the lower plate of Precambrian rocks may have occurred at the time the granitic intrusion was emplaced. The Paleozoic and late Precambrian sedimentary rocks in the mountains bordering Death Valley occur in a series of thrust plates of the Amargosa thrust system. The thrusting moved younger rocks westward onto older ones. Within a thrust plate the rocks have uniform homoclinal dips, almost invariably to the east. 'The major structural units are grouped into four klippen and three fensters. The most completely exposed klippe is at Tucki Mountain where Paleozoic formations ranging in age from Early Cam- brian to Permian have been thrust westward onto the King- ston Peak(?) Formation of late Precambrian age. 'The klippe is divided into four plates by thrust faults that, towards the east, branch upward from the main one at the base. Along these branch faults the displacement is 4 miles westward; H4 STRATIGRAPHY AND STRUCTURE A83 along 'the main fault the displacement must be very much more than that. The Panamint Range south of Tucki Mountain also is a klippe of east-dipping Paleozoic rocks thrust westward onto the Pre- cambrian. The thrust fault at the base, the Amargosa thrust, is exposed at the east foot of the range. There Paleozoic for- mations in the upper plate dip east and rest on Precambrian metamorphic rocks in the lower plate. Other thrust faults within the Paleozoic formations also seem to be branches ex- tending upward from the Amargosa thrust,. Some of these branch faults are intruded by sills from the granite at Hanaupah Canyon. The south end of the Funeral Mountains and the southern part of the Grapevine Mountains comprise klippen of Paleozoic formations thrust westward onto the Precambrian. Between these two thrust plates is a fenster of Precambrian formations forming the northern part of the Funeral Mountains. The two klippen may join under the Amargosa desert east of the Funeral Mountains. The fenster in the northern part of the Funeral Mountains is formed by anticlinally domed Precambrian formations. So also is the west side of Tucki Mountain, another fenster, and the Black Mountains. The uplift at the Black Mountains is divided into three fensters, each a smooth-surfaced dome or turtleback. It is suggested that the thrust plates of the Amargosa thrust system in part are detachment blocks, and that the turtleback fault surfaces were denuded tectonically. Over the main part of the Panamint Range, Bouguer gravity- anomaly values are lower than over the mountains east of | Death Valley and lower than those over the Slate Range to the southwest, suggesting that the Panamint Range is under- lain by a granitic mass. In terms of deep crustal structure the geologic and gravity data suggest two possibilities. One is that deep under the Panamint Range is a large granitic intrusion that connects westward with the Sierra Nevada batholith and forms a bulbous thickened edge of the batholith. A second possibility is that the edge of the batholith is in the area that is seismically active west of the Panamint Range and that the deeply buried granite is mostly Precambrian. By the latter interpretation the granites at Skidoo and Hanaupah Canyon, and other granitic intrusions, could be attributed to palin- genesis of the Precambrian granitic rocks. INTRODUCTION By CnxartEs B. Hunt LOCATION AND DESCRIPTION OF THE VALLEY Death Valley, one of the valleys of the Basin and Range province, is at the south edge of the Great Basin, about midway between the Colorado River and the Sierra Nevada. Just to the south is the Mojave Desert (fig.:1). The valley trends north-south between block faulted mountains (fig. 2). In the main part of the valley, the floor is a flat playa crusted with salts, one of the great natural saltpans of the world. The saltpan covers more than 200 square miles and is 250-280 feet below sea level. It is the sink for drainage from a hydrologic basin covering 8,700 square miles. An arm of Death Valley extends 60 miles north-northwestward from the saltpan and rises to about 3,000 feet in altitude. Discharging into the south end of the saltpan is the Amargosa River which rises northeast of Death Valley, flows southward along a valley 25 miles to the east, and then makes a great U-turn to discharge into the south end of Death Valley. The mountains bordering Death Valley are north- trending fault blocks. Largest and highest of these blocks is the Panamint Range along the west side (fig. 3). Its highest peak, which is more than 11,000 feet above sea level, is only 12 miles from the edge of the saltpan. Both in terms of local relief and local rug- gedness, this is one of the roughest terrains in the United States. Along the east side of the saltpan are the Black Moun- tains which rise precipitously from the edge of the salt- pan to a summit at about 6,000 feet in altitude (fig. 4). Northeast of the saltpan and set back from it by long gravel fans are the Funeral Mountains (fig 5). To the north are the Grapevine Mountains which lie along the east side of the northwest arm of Death Valley. Death Valley is a desert area. The floor of the valley in fact is the hottest and driest part of the United States. Annual rainfall is only 1.65 inches; the evaporation rate is 150 inches annually! On the floor of the valley a maximum summer temperature of 134°F has been recorded. Minimum temperatures in winter almost never reach as low as freezing. The mountains, of course, have more moderate temperatures and consid- erably more precipitation ; the summit of the Panamint Range is covered with snow most of each winter. Addi- tional climatic data are given by Hunt and Robinson (in Hunt and others, 1965). There is little surface water in Death Valley, but springs with potable water are surprisingly numerous. Death Valley below an altitude of about 5,000 in part of the Lower Sonoran zone, characterized by the cre- osotebush. Vegetation is scanty, and there are almost no trees except for some mesquite around the edge of the saltpan where there is a zone of springs. The saltpan, covering more than 200 square miles, is without vegeta- tion. The Panamint Range above 7,500 feet is wooded with pifion pine and juniper; limber and bristlecone pines grow at the summit. f The archeologic record in Death Valley reveals a long series of prehistoric occupations, or seasonal visitors, going back to early Recent and perhaps to late Pleisto- cene time. The first recorded entrance of white people into the valley was in 1849 when a party of emigrants, heading for the gold fields in California, left their cara- van, sought a short cut, and became lost. One of the groups gave the name to the valley. During the next 2 4.4; GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA A4 weiseip 10 esuy & I- 0 a *' / * 9M YUVAHN "lts ino not ey x, :a 4 Rl Aut >v03i es desu S i wocwwawawwfi r S3TIW OS Ot epeAaN euotyg pug '}49s9( oat[fopy 'utseq uoyjnos oy} 03 «atreA yje9G 30 Snjeqooies ogee ea 3°14 STRATIGRAPHY AND STRUCTURE A5 ONN SHEARS IGUORTANS <-> T ce Aames ADs BNN SPRING CAMINOIN_ ABRNIGPRING SAINON \_ «-__- R m>\\‘°‘\“ ; aa Tees n anm ._‘\,,,,\;m\,..n._f.\ ere g AX. Les % Recumiti _- n" g 2~_F § E Tiper ii ria, aire z ¢ ia .f - & - \ Fae ol.}: gee Cl > s % «os a eae -. Fara “fig?“ <4 rs 39 a i >=" s he At c # - Mongo p > = < nex, am\zfi¢&w\w\w“ % . 2 ga ys (Ahi c y, qx BBDNINTER onance." -a... sx." P m_ Ar § = 3 - AAAE IP - 7. cnt nome oe "inter ttt SPaANG 5—1 $7 ”If/j)???” fz E {._ -- %f mnt ~-" -_- " 22. & : >- - Pas 4 5. t ~ ‘ aa. ~a_-_2 * «l Mmg p. f an t- =% ease . Soran -ne Sey " myo, Soh Hx ___-~-+ coy I0NnBALL S k%\\i ~s es ae. _ ' -. 3,373 ay > 2 m ». FUNERAL TAINS ans 2 T- BMA ~ j N MOUN .tn . Ficur® 2.-Block diagram of Death Valley, Calif., looking south. 1. Nevares Spring. 3. Texas Spring. 5. Coyote Hole. 2. Travertine Spring. 4. Corkscrew Canyon. 6. West Side Borax Camp (Shoveltown). GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA A6 'JPITEW 'H 'H 44 udeasojoug C Stm: STRATIGRAPHY AND STRUCTURE FIGURE 4.-View southeast across Death Valley to the south end of the saltpan and mouth of the Amargosa River. Photograph by W. B. Hamilton. 30 years prospectors searching for metal mines visited the mountains bordering Death Valley, and many of the local place names were given by them or commemorate their excursions. Early in the 1880's borax was discovered on the Death Valley saltpan and the discovery led to production. In the next year or two richer deposits were found in the northern part of the Black Mountains and production shifted there. Produce from these mines was hauled to Mojave by the well-advertised 20-mule teams. In the first decade of this century the Skidoo mining district produced a little gold, but the Death Valley area has produced very little metal. Since the midtwenties min- ing activity has been slight, except for the production of tale in the mountains bordering the south end of Death Valley. Land surveys in Death Valley were begun in 1857. The fact that the valley floor is below sea level seems to have been discovered about 1861 as a result of baro- metric observations by one of the several Nevada-Cali- fornia Boundary Commissions. This was confirmed in the midseventies by the Wheeler Surveys when satis- factory maps of the area first became available. During 1905-06 the first topographic map of the area was pre- pared and the altitude of the valley floor determined instrumentally. Death Valley was made a National Monument in 1933. It has become a popular winter resort, and good high- ways lead to it from all directions. Two major scientific contributions have come from Death Valley, one in the field of plant ecology, the other in geology. The ecology contribution was made in 1893 by Frederick V. Coville, a member of the Death Valley expedition. His report on the botany and its relation- ship to the environment is a classic. The major contribution in geology was by Levi F. Noble (1941) who was the first to demonstrate clearly the existence of westward-directed thrust faults in the southern part of the Great Basin. MAPPING OF THE VALLEY Different parts of the geologic map (pl. 1) were pre- pared in very different ways and they are of quite dif- ferent quality. The saltpan was mapped by traverses across the valley floor at 1-mile intervals. The ground changes were plotted on aerial photographs, and the boundaries traced along the valley floor to tie into the preceding day's AS GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA FisurB 5.-View northeast across Death Valley to the Black Mountains and Funeral Mountains. Photograph by W. B. Hamilton. traverse. The boundaries then were projected directly from the photographs onto the topographic base maps. Mapping of the gravel fans involved sufficient tra- verses on each fan to identify the gravel deposits ac- cording to their distinctive color and tone on the aerial photographs. The boundaries of the several formations then were sketched with much generalization on the photographs, and these lines were transferred by pro- jection and inspection to the topographic base. In gen- eral, the boundaries of the older of the late Pleistocene gravel (No. 2 gravel) are shown by the contours; the younger gravels commonly are in such small areas that a great deal of generalization was necessary, so much so that accurate projection onto the topographic base seemed an overrefinement. The lower parts of the mountains were mapped on the ground. For the most part the traverses were along the valleys and along the ridges, although this is at right angles to the contacts. The higher parts of the mountains were mapped by helicopter. Within limits, this mapping from the air could be checked by tracing the formations to the lower parts of the moun- tains where mapping had been done on the ground and where fossil collections had helped control it. Later, some of the most questionable areas were checked by traverses down the ridges and canyons from the summit of the Panamint Range to the floor of Death Valley. In the course of mapping the Paleozoic formations, about 100 collections of fossils were obtained. Their locations are shown on the geologic map, and the con- tents of most of the collections are described with the formations. It is expected that future work will show that the formations in some fault blocks have been in- correctly identified, but the fossil collections show the limits to which such corrections may be extended. Fieldwork was interrupted while parts of the study still were incomplete. In particular, the Tertiary for- mations, the granitic intrusions, and the older of the Precambrian sedimentary formations need more study. ACKNOWLEDGMENTS Numerous specialists have contributed to various parts of this general report on the geology of Death Valley, and their contributions are acknowledged in the sections dealing with the particulars of the geology. Acknowledgment here is made to James Gilluly who was largely responsible for getting the project launched and persuading me to undertake it. T. S. Lovering visited the project each of the first 5 years and contrib- uted ideas and other assistance on many phases of the STRATIGRAPHY AND STRUCTURE geology; his encouragement and guidance were a very real benefit to the project. My wife, Alice P. Hunt, studied the archeology while I was working on the geology. We found that work- ing together in the field was of mutual benefit, and each . of us was able to assist the other. We were headquartered in the field with the staff of the National Park Service. Their many favors and hospitality greatly assisted the project and made the field seasons most pleasurable. STRATIGRAPHY By B. HunT Precambrian rocks exposed in the mountains border- ing Death Valley include at least 3,000 feet of rocks be- longing to the crystalline basement and a sequence of much younger and but slightly metamorphosed sedi- mentary rocks, mostly clastic, totaling roughly 10,000 feet thick, referred to as the Pahrump Series. Overly- ing the Pahrump, and also included in the Precambrian are three formations-the Noonday Dolomite, Johnnie A9 Formation, and Stirling Quartzite, totaling about 7,000 feet thick. Paleozoic rocks, mostly carbonate rocks and repre- senting all the periods from Cambrian to Permian, ag- gregate about 20,000 feet thick. Triassic formations 8,000 feet thick are exposed just outside the mapped area; they include carbonate rocks, fine-grained clastic rocks, and volcanics. Table 1 summarizes the forma- tions recognized in the area and nearby. The mapping in the Panamint Range and Funeral Mountains on which this report is based was done by Hunt, partly by conventional ground methods and partly by helicopter (Hunt, 1960). The mapping of the Precambrian rocks in the Black Mountains was done by Harald Drewes (1963). The distribution of the formations is shown on the geologic map (pl. 1). Most of the identifications of Cambrian fossils are by Palmer; most of the identifications of Ordovician fos- sils are by Ross. Other palentologists who identified and reported on the fossils include Ellis L. Yochelson, TaBus 1.-Precambrian, Paleozoic, and Triassic formations exposed in the Death Valley area System Series Formation Lithology and thickness Characteristic fossils Triassic Butte Valley for- Exposed in Butte Valley 1 mile south | Ammonites, smooth-shelled mation of of this area, 8,000 ft of metasedi- brachiopods, belemnites, and Johnson (1957). ments and volcanics. hexacorals. Pennsylvanian Formations at Conglomerate, limestone, and some Beds with fusulinids, especially and Permian east foot of shale. Conglomerate contains cob- Fusulinella. Tucki Moun- bles of limestone of Mississippian, tain. Pennsylvanian, and Permian age. Limestone and shale contain spherical chert nodules. Abundant fusulinids. Thickness uncertain on account of faulting; estimate 3,000 3 ft +; top eroded. 8 E Mississipian Rest Spring Shale | Mostly shale, some limestone; abun- None. §= and Penn- dant spherical chert nodules. Thick- 3 sylvanian(?) ness uncertain because of faulting; ) estimate 750 ft. O Mississipian Tin Mountain Mapped as 1 unit. Tin Mountain Mixed brachiopods, corals, and Limestone and Limestone, 1,000 ft thick, is black crinoid stems. Syringopore younger lime- with thin-bedded lower member and (open-spaced colonies), stone. thick-bedded upper member. Un- Caninia cf. C. cornicula. named limestone formation, 725 ft thick, consists of interbedded chert and limestone in thin beds and in about equal proportions. Devonian Middle and Lost Burre for- Limestone in light and dark beds 1-10 | Brachiopods abundant, espec- Upper Devo- mation. ft thick give striped effect on moun- ially Spirifer, Cyrtospirifer, nian. tainsides. Two quartzite beds, Productilla, Carmarotoechia, each about 3 ft thick, near base; ,_ Atrypa. numerous sandstone beds 800-1,000 | Stromatoporoids. ft above base. Top 200 ft is well- Syringopora (closely spaced bedded limestone and quartzite. colonies). Total thickness uncertain because of faulting; estimated 2,000 ft. Silurian Silurian and Hidden Valley Thick-bedded, fine-grained, and even- | Crinoid stems abundant, includ- and Devonian Lower De- Dolomite. grained dolomite; mostly light color. ing large types. Favosites. vonian. Thickness 300-1,400 ft. 776-623 O-66-2 A10 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA TaBus 1.-Precambrian, Paleozoic, and Triassic formations exposed in the Death Valley area-Continued System Series Formation Lithology and thickness Characteristic fossils Upper Ordovician | Ely Springs Dolo- | Massive black dolomite; 400-800 ft Streptelasmatid corals: Grew- mite. thick. ingiikia, Bighornia. - Brachio- pods. a Middle and Eureka Quartzite Massive quartzite, with thin-bedded None. #3 Upper(?) Ordo- quartzite at base and top; 350 ft E vician. thick. 0 Lower and Mid- | Pogonip Group Dolomite, with some limestone, unit Abundant large gastropods in € dle Ordovician. at base; shale unit in middle; mas- massive dolomite at top: O sive dolomite unit at top. - Thick- Palliseria and Maclurites, ness, 1,500 ft. associated with Receptaculites. In lower beds: Protopliomer- ops, Kirkella, Orthid brachio- pods. Upper Cambrian | Nopah Formation | Highly fossiliferous shale member 100 | In upper part, gastropods. In ft thick at base; upper 1,200 ft is basal 100 ft, trilobite trash dolomite in thick alternating black beds containing: Elburgic, and light bands about 100 ft thick. Pseudagnostus, Homagnostus, Total fthickness of formation 1,200- Elvinia, Apsotreta. 1,500 ft. Middle and Bonanza King Mostly thick-bedded and massive The only fossiliferous bed is the Upper Cam- Formation. dark-colored dolomite; a thin- shale below the limestone brian. bedded limestone member 500 ft member that occurs near the thick 1,000 ft below top of the for- middle of the formation. mation; 2 brown-weathering shaly This shale contains linguloid units, the upper one fossiliferous, brachiopods and trilobite = about 200 and 500 ft, respectively, trash beds with fragments of .8 below the thin-bedded member. "Ehmaniella." 5 Total thickness uncertain because € of faulting; estimated about 3,000 ft 5 in Panamint Range; 2,000 ft in Lower and Mid- dle Cambrian. Lower Cambrian Carrara Forma- tion. Zabriskie Quartz- ite. Funeral Mountains. An alternation of shaly and silty mem- bers with limestone members; transitional between the underlying clastic formations and the overlying carbonate ones. Thickness about 1,000 ft but variable because of shearing. Quartzite, mostly massive and granu- lated due to shearing; locally in beds 6 in. to 2 ft thick; not much crossbedded. - Thickness more than 150 ft; variable because of shearing. Numerous trilobite trash beds in lower part yield fragments of olenellid trilobites. No fossils. Lower Cambrian Wood Canyon Basal unit is well-bedded quartzite A few scattered olenellid trilo- Precambrian tion Noonday Dolo- mite Unconformity- part purple. Basal member 400 ft thick is interbedded dolomite and quartzite with pebble conglomerate. Locally, tan dolomite near the mid- dle and at the top. Thickness more than 4,000 ft. In southern Panamint Range, dolomite in indistinct beds; lower part cream colored, upper part gray. Thickness 800 ft. Farther north where map- ped as Noonday(?) Dolomite, con- tains much limestone, tan and white, and some limestone conglomerate. Thickness about 1,000 ft. & E g and Lower Formation. about 1,650 ft thick; shaly unit bites and archaeocyathids in Rok: s Cambrian(?). above this 520 ft thick contains the upper part of the forma- g e 2 lowest olenellids in the section; top tion. 5 E unit of dolomite and quartzite 400 Scolithus? tubes. © ft thick. Stirling Quartzite Well-bedded quartzite in beds 1-5 ft | None. thick comprising thick members of quartzite 700-800 ft thick separated by 500 ft of purple shale; crossbed- ding conspicuous in quartzite. Maxi- mum thickness about 2,000 ft. Johnnie Forma- Mostly shale, in part olive brown, in | None. Scolithus? tubes. STRATIGRAPHY AND STRUCTURE All TaBum® 1.-Precambrian, Paleozoic, and Triassic formations exposed in the Death Valley area-Continued System Series Formation Lithology and thickness Characteristic fossils Pahrump Series Kingston Peak(?) | Mostly conglomerate, quartzite, and None. Formation shale; some limestone and dolomite near middle. At least 3,000 ft thick. Although tentatively assigned to the Kingston Peak Formation, similar rocks along the west side of the Panamint Range have been identified as Kingston Peak. Beck Spring Dolo- | Not mapped; outcrops are to the west. | None. mite Blue-gray cherty dolomite; thick- : ness estimated about 500 ft. Iden- 'E tification uncertain. ‘E Crystal Spring Recognized only in Galena Canyon None. 3 Formation and south. Total thickness about A 2,000 ft. Consists of a basal con- A glomerate overlain by quartzite that grades upward into purple shale and thinly bedded dolomite; upper part, thick-bedded dolomite, diabase, and chert. Tale deposits where diabase intrudes dolomite. -- Unconformity- Rocks of the Metasedimentary rocks with granitic None. crystalline base- intrusions. ment P. E. Cloud, Jr., W. A. Oliver, Jr., Chas. W. Merriam, Mackenzie Gordon, Jr., and Richard Rezak. I have illustrated a number of the formations with pictures of slabs of fossiliferous rock, which some may find helpful as lithologic guides to the formations, as pointed out 30 years ago by Noble (1934, p. 175). (Tri- lobites are the most abundant fossils in the Cambrian beds; gastropods in the Lower Ordovician beds; corals in the Upper Ordovician, Silurian, and Devonian ; and crinoids in the Mississippian. Such generalized obser- vations are very helpful in identifying rock formations that have been severely faulted and crumpled. PRECAMBRILAN SYSTEM ROCKS OF THE CRYSTALLINE BASEMENT Precambrian rocks of the crystalline basement in this area are most extensive in the steep front of the Black Mountains. - Some smaller outcrops are at the head of Galena Canyon and along the east foot of the Panamint Range north of Hanaupah Canyon. The outcrop of the Precambrian in the head of Ga- lena Canyon is mostly schist. The foliation in the schist, which is about vertical, is cut off discordantly by conglomerate at the base of the Crystal Spring For- mation, the lowest formation in the Pahrump Series. - The contact is thought to be depositional. The outcrop of Precambrian metamorphic rock along the east foot of the Panamint Range north of Hanaupah Canyon marks the lower plate of a thrust fault, probably the Amargosa thrust; this lower plate has been the site of much igneous activity. The rocks are referred to as the Amargosa thrust complex and are described more fully on page A 129. The Precambrian in the Amargosa complex is mostly gneiss, much of which is highly distinctive augen gneiss like that underlying the Amargosa thrust southeast of Mormon Point (Noble, 1941). The augen are feldspar, ,-1 inch long, and constitute from 10 to 40 percent of the rock. The matrix is quartz and coarse-grained mica, mostly biotite. Enclosed in the augen gneiss are crushed lenses of biotite schist and some muscovite schist. Above the augen gneiss is a crush zone consisting of mylonite and breccia along a thrust fault, probably the Amargosa thrust. The upper plate here is Stirling Quartzite. The gneiss is cut by a swarm of northward-trending felsite dikes; their strike parallels the foliation in the gneiss. Northward the gneiss extends under interlayered vol- canic and Paleozoic rocks suggestive of the "chaos" as described by Noble (1941). Underlying the gneiss is a granitic intrusion. Much interest attaches to the age of the metamorph- ism of this gneiss, because part of the metamorphism may have occurred during the early or middle Ter- tiary when the thrust faulting occurred and the granitic intrusion became emplaced. The rocks of the Black Mountains have been described by Drewes (1963) who has mapped the Funeral Peak quadrangle. The following descriptions are sum- marized from his report. A12 The rocks comprise metadiorite and smaller bodies of metasedimentary schist, gneiss, and marble. The schist, gneiss, and marble underlie the lower parts of north- west-trending mountain spurs at Mormon Point and the mountain southeast of Copper Canyon. The schist and gneiss are in about equal proportions. Near Mor- mon Point, marble is equally abundant, but elsewhere it is less so. The thickness of the metasedimentary rocks is unknown, but is of the order of many hundreds of feet. The schist generally consists of quartz (10-25 per- cent), plagioclase. (15-25 percent), chlorite (80-60 per- cent), biotite (10-20 percent), and sericite ; it has minor amounts of magnetite, sphene, and possibly potassium feldspar. The gneiss consists largely of quartz (20-40 percent), plagioclase feldspar (15-40 percent), and potassium feldspar (as much as 40 percent) in light-colored layers, mostly less than 1 inch thick, alternating with thin dark layers of biotite. Some facies of the gneiss have layers of muscovite instead of biotite. The layers are mostly even and distinct. In places the gneiss contains feld- spar augen 1-1 inch long. Veins and irregular masses of epidote are common. The marble is white to light olive gray and weathers yellowish gray to pale yellowish brown. It occurs in lenticular beds ranging from a few feet to a few tens of feet thick interbedded with the schist or gneiss. Most of the marble is coarsely crystalline calcite, but some at Mormon Point is dolomitic. Most of the front of the Black Mountains is Pre- cambrian metadiorite. This rock, which is not foliated, and consists largely of plagioclase feldspar (40-65 per- cent), hornblende (20-40 percent), and biotite (3-15 percent). It appears to be intrusive into the metasedi- mentary rocks. In the course of my survey, samples were collected from all the formations for spectrographic scanning for trace elements. Table 2 lists the trace elements found in a piece of schist from Galena Canyon and in a piece of gneiss from the Black Mountains above Badwater. Analyses of the augen gneiss and biotite gneiss in the Amargosa thrust complex at the east foot of the Pana- mint Range north of Hanaupah Canyon are given in table 26. The trace elements in the schist and gneiss are re- markably alike, considering the very different lithol- ogies and locations of the rocks. They differ from the gneisses in the Amargosa thrust complex in con- taining more lead, manganese, cobalt, vanadium, titanium, boron, and gallium. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA TABLE 2.-Trace elements in Precambrian metamorphic rocks [Analyses of the metamorphic rocks in the Amargosa thrust complex, where the rocks may have been subject to Tertiary alteration, are given in table 26. Semi- quantitative spectrographic analyses by Uteana Oda U.S. Geol. Survey. Values are in parts per million, except Mg, which is given in pennant] Schist in Gneiss above Element Galena Badwater Canyon Phir Nio ccc. e t= a ue anale a 30 30 500 700 50 30 150 100 50 30 20 70 150 300 20 20 3 1 5, 000 10, 000 70 70 70 30 70 50 100 30 700 2, 000 20 700 1.5 5 NotE.-Also found: W, <20; Nb, <10; Zn, <200 La, <50; Sc, <10; Mo, <2 or less; Ag, <1; Bi, <5; Sn, <10; As, <500; Sb, <50 Metamorphism of schist under the Pahrump Series in the southern Panamint Range is dated as 1,700 mil- lion years by potassium-argon methods and 1,480 mil- lion years by strontium-rubidium methods (Wasser- burg and others, 1959). A comparable age has been determined for the augen gneiss zircon in the Amar- gosa thrust complex (T. W. Stern, written commun., 1965). PAHRUMP SERIES The Pahrump Series, named for Pahrump Valley 50 miles east of Death Valley (see index map, fig. 1; Hewett, 1940, 1956), in its type area consists of three formations. At the base is the Crystal Spring Forma- tion, about 2,000 feet thick, consisting of a basal quartz- itic member overlain by thick-bedded dolomite, dia- base, and chert. Above the Crystal Spring Formation is the Beck Spring Dolomite, 1,100 feet thick, which is made up mostly of beds of light-blue-gray dolomitte 2-4 feet thick. At the top, in the type area, is the Kingston Peak Formation, 1,000-2,000 feet thick, which consists of sandstone and shaly sandstone at both the top and base, separated by a middle unit of conglomerate with cobbles as much as 10 inches in diameter (Hewett, 1956). In the Silurian Hills, southeast of Death Valley, the rocks assigned to the Pahrump Series are more than 11,000 feet thick, but correlation with the type section is uncertain (Kupfer, 1960, p. 188). In the Alexander Hills of Pahrump Valley, rocks assigned to the Pah- rump total 8,000 feet thick and appear to represent all three of the formations recognized in the type section (Wright, 1954). STRATIGRAPHY AND STRUCTURE A section of the Pahrump Series very similar to that in the type area is present also in the Ibex Hills in the southern part of Death Valley (Wright, 1952), an area about midway between the type locality and the south- ern part of the Panamint Range. In the southern part of the Panamint Range, both in Galena Canyon and in the section of Warm Springs Canyon south of the area I studied, only the Crystal Spring Formation is present. It rests with angular un- conformity on schist of the crystalline basement and is overlain by Noonday Dolomite. This contact between the Crystal Spring Formation and the Noonday Dolo- mite probably is a thrust fault and not a depositional contact. In any case, younger formations of the Pah- rump Series are not present in the southeastern part of the Panamint Range, but they are present along the summit and west slope of the range. On the west side of the Panamint Range the Kingston Peak Formation rests on the Precambrian crystalline basement; the Crystal Spring Formation is absent there (Johnson, 1957, p. 360). Locally, a dolo- mitic limestone that is much crushed occurs along the contact between the Kingston Peak Formation and underlying erystalline rocks (Murphy, 1932, p. 343) ; this dolomitic limestone may correlate with the Beck Spring Dolomite. The spatial relationships of the three formations and their possible structural relations are illustrated on figure 6. CRYSTAL SPRING FORMATION The Crystal Spring Formation in Galena Canyon is about 2,000 feet thick. It consists of basal conglom- erate overlain by quartzite that grades upward into purple shale and thinly bedded dolomite. The upper part of the formation consists of thick-bedded dolomite, diabase, and locally, massive chert (fig. 7). The follow- ing is a section of the Crystal Spring Formation meas- ured in Galena Canyon. A13 Section of Crystal Spring Formation in Galena Canyon Top of section is base of Noonday Dolomite; the contact is con- cealed and may be a thrust fault (see fig. 6). Feet 450 150 _.... _ 22 cs UIL A ole ea i n anes eee ain aa a hane man Chert, denge,- .- 1 _L _ cu _ __ Lee ccw nee amen Dolomite, weathers light brown; lower 50 ft in beds 6- 20 ft thick, upper 125 ft massive. Talcose at base__-. Diabase, much-weathered, calcareous; red iron oxide nlong ASEUPOS-~__ _o L all cc online Dolomite, well-bedded and thin-bedded ; beds 1 in to 2 ft thick; finely granular, grains less than 0.1 mm with vugs and veinlets of coarse dolomite (grains 0.5 mm) ; quartz grains (about 0.5 mm in diameter) at center of vugs (fig. 8B); chert lenses; weathers light brown; talcose where intruded by diabase sills____________-- Purple argillite or shale, some brown-weathering dolo- mitic shale, some quartzite with sericitic groundmass. Quartzite, crossbedded, beds 1 in to 3 ft thick; in part conglomeratic with pebbles of quartzite, red chert, and gneiss as much as 6 in. in diameter. Well-rounded grains of quartz and microcline and clastic biotite in dolomitic groundmass (fig. 84). Some beds weather white; others are black, especially those with carbonate in matrix Conglomerate, light gray to white but weathers brown ; quartz pebbles as much as 1 in. in diameter, but most of the unit is grit rather than conglomerate. Beds 6 in. T0 .A Ft ooo uel assem- s 300 300 250 150 150 100 Total thickness of Crystal Spring Formation includ- ing 750 It of 1, 850 Base. Angular unconformity. The basal conglomerate overlies steep to vertical foliation in Precambrian schist. Table 3 shows the trace elements found in several dif- ferent rock types in the Crystal Spring Formation. These samples are from Galena Canyon and are to be compared with the analysis of the schist from there (table 2). The quartzite and shale are most like the schist, but they contain substantially less of most trace elements, especially nickel, cobalt, vanadium, titanium, gallium, and chromium. NW SE Harrisburg Flat Galena Canyon | Noonday(?) DoLo_rpite [--+ ease oompa c iy." Kingston Peak(?) + al i I \- -| Kingston Peak(?) of ~- A- § axe Formation 2 00°] Beck Spring .--. | Crystal Spring ors FF Dolomite 3 Formation 000 0 0 0 8.0 © o: 0?) <+ goes ? H +000 0 S 5 i § § Precambrian $ g metamorphic rocks ia A/ More. " FIGURE 6.-Idealized diagram illustrating distribution and possible structural relationship of the three formations of the Pahrump Series in the Panamint Range. A14 GENERAL GEOLOGY OF 4 DEATH VALLEY, CALIFORNIA 7.-Crystal Spring Formation in Galena Canyon, view northwest. Q, quartzite member; sd, purple shale and thin-bedded dolomite ; di, diabase sill with talcose beds (T) where the sill is in contact with dolomite; do, massive dolomite at top of the formation. In distance is Noonday Dolomite (p€n) capped by Johnnie Formation (pCj). The Crystal Spring Formation is of much interest economically because it contains highly productive de- posits of tale. The commercial product, which con- sists of the mineral tale [HMg;(Si0O;).] and tremolite [CaMg;(SiO;),] with accessory serpentine and calcite (Wright and others, 1954), occurs as an alteration product of dolomite where the dolomite is intruded by diabase (fig. 7). The fact that diabase sills do not occur in formations younger than the Crystal Spring, even where younger formations of the Pahrump Series are present, has led to the interpretation that the sills and the alteration associated with them predate deposition of the Beck Spring Dolomite (Wright, 1952, p. 15). BECK SPRING DOLOMITE Rocks probably equivalent to the Beck Spring Dolo- mite, locally referred to as the Marvel Dolomitic Lime- stone by Murphy (1930), crop out at a dozen places along the west side of the Panamint Range west of the mapped area between the Kingston Peak Formation and underlying basement rocks (Murphy, 1932, p. 343). STRATIGRAPHY It is a bluish-gray cherty rock containing about 30 per- cent CaO) and 20 percent MgO, it also contains tremo- lite and muscovite (Murphy, 1932, p. 348). The for- Microcrystalline * dolomite FicUrB 8.-Micrographs of quartzite (4) and dolomite (B) in Crystal Spring Formation. The quartzite consists of well- rounded grains of quartz (Q) and microcline (M) and other feldspar (F) in a dolomitic and sericitic matrix. The dolo- mite is finely granular with vugs of coarse dolomite (D) at the center of which are grains of quartz (Q). Diameter of field, 2.5 mm. TABLE 3.-Trace elements in the Crystal Spring Formation [Semiquantitatiive spectrographic analyses by Uteana Oda, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] 4 Dark Red- Element | Quartz-|Dolomite| Diabase chert in | Brown Talc | Shale ite diabase | chert in diabase Pp.... 30 20 70 15 | 1, 000 10 10 Mn-__-| 500 500 1, 000 300 20 50 500 Cu..l: 5 5 150 15 70 1 2 Telos. 100 20 100 100 150 10 30 Nii... 5 <5 50 30 20 <5 5 Co:... <10 | «10 50 10 15} «10 <10 10 15 200 200 150 20 20 Tul.... 15 10 15 15 30 | <10 10 1] <1 <1 <1 <1! ' <1 2 300 100 | 20, 000 | 5, 000 | 7, 000 200 700 B..... 20 | <10 50 10 10 10 30 Ca:.-.. 10 | <10 50 50 50 <5 5 Cr.:.:. 10 5 70 100 100 5 5 8 3 2 |: ps5 >5 NotE.-Also found: La, 50 or less; Zn, 200; Sc, 15 in diabase, 10 or less in others; Mo, <2; Bi, <1; Sn, <10; As, <500; Sb, <50; W, <20; Nb, <10. AND STRUCTURE A15 mation is very much sheared and contorted-too much so to determine the thickness. The Crystal Spring Formation is absent in that area. An interpretation of the structural relationships is illustrated diagrammati- cally on figure 6. KINGSTON PEAK(?!) FORMATION The youngest formation of the Pahrump Series, the Kingston Peak Formation, crops out extensively along the west side of the Panamint Range. Similar rocks tentatively assigned to this formation occur at Harris- burg Flat, Tucki Mountain, and the northern part of the Funeral Mountains. Along the west side of the Panamint Range, the Kingston Peak Formation has been divided into three members (Johnson, 1957, p. 360). 'The lower member, 370-1,600 feet thick, is conglomeratic graywacke; above this is limestone 30-170 feet thick, and at the top is con- glomerate, sandstone, and shale 260-1,000 feet thick (Johnson, 1957, p. 360-361). In the northern part of the Panamint Range, in the vicinity of Harrisburg Flat, the rocks mapped as Kings- ton Peak(?) Formation are intruded by the granite at Skidoo in addition to being much faulted and folded. The stratigraphy there has not been determined satis- factorily. The most distinctive rocks are the stretched- pebble conglomerates. Some of these have a quartzite matrix, others have a sandy dolomitic matrix. The clasts are of quartzite and limestone. Much of the for- | mation is platy quartzite, and there is some limy dolo- mite and limestone. In places the upper part is dark shale. Overlying these dominantly clastic beds is a thick section of carbonate rocks mapped as Noonday ( ?) Dolomite, and probably separated from the Kingston Peak(?) Formation by a flat fault. On Tucki Moun- tain some carbonate rocks below the thrust fault are doubtfully included in the Kingston Peak (?) Forma- tion. Beds assigned to the Kingston Peak(?) Forma- tion are at least 3,000 feet thick. Six samples of the Kingston Peak(?) Formation were collected for spectrographic analysis. Three were obtained from the vicinity of Harrisburg Flat in the Panamint Range and three from the base of the Funeral Mountains. The analyses are given in table 4. The trace elements in the various rock types are quite dif- ferent in the two areas. The limestone in the Panamint Range samples contains a greater concentration of trace elements than does the limestone from the Funeral Mountains. The quartzites differ less and their differ- ences are more spotty. The differences, despite the small number of samples, cast further doubt on the correlation of the Kingston Peak(?) Formation be- tween the Panamint Range and the Funeral Mountains. A16 TaABL® 4.-Trace elements in the Kingston Peak(?) Formation. [Semiquantitative spectrographic analyses by Uteana Oda and E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] Funeral Mountains Panamint Range Element Dolo- | Lime- | Quartzite | Limestone Shale Quartz mite stone ite 15 20 300 10 30 50 Mn......./1, 500 200 500 1, 000 2, 000 700 Cul:.._.. 2 10 150 100 150 200 30 10 200 500 700 700 5 7. 50 70 100 10 Co...... <10 | <10 20 15 30 10 VEL 10 20 100 200 200 70 10 20 20 50 50 70 Be...... <1 <1 1 1 1 1 Tis -lecsss 300 300 | 10,000 | 10,000 | >10, 000 | 7, 000 B...QL.l. 10 | <10 20 15 200 15 Se...... <10 | <10 <10 20 50 <10 Ca.-.--.. <5 | <20 20 <20 <20 <20 La...... <50 | <50 <50 50 50 50 Cr'.....: T- 10 50 100 500 30 100 50 1, 000 1, 000 1, 500 | 3, 000 or... _... 1, 000 200 100 700 200 150 Mg..:::-. ys | (>5 1.5 5 5 1 NotE.-Also found: Mo 10 in shale in Panamint Range; <5; in other samples; Sn, ‘svlo; 5Aog, <1; Ge, <20; As, <1,000; Sb, <200, In, <50; Cd, <50; Tl, <100; Ta, <50; , <50. NOONDAY DOLOMITE Overlying the Pahrump Series is the Noonday Dolo- mite. At its type locality at the south end of the Nopah Range, about 50 miles east of the Panamint Range, the formation consists of about 1,500 feet of light-cream- colored dolomite with sandy beds near the top (Haz- zard, 1937b, p. 300). In the southern part of the Panamint Range, in Galena and Six Spring Canyons, the Noonday Dolo- mite rests on the Crystal Spring Formation of the Pahrump Series The contact between the 2 forma- tions, which is concealed by rubble from the dolomite, probably is a flat fault that removed the upper 3,500, feet of the Pahrump Series and that cuts across at least 600 feet of the upper part of the Crystal Spring For- mation (fig. 6). The Noonday Dolomite is conform- ably overlain by the Johnnie Formation. The Noonday Dolomite in Galena and Six Spring Canyons consists of a light-cream-colored lower mem- ber about 500 feet thick and a gray upper member about 300 feet thick. Indistinct bedding in both members is characteristic of the formation throughout the region. Structures suggestive of Scolithus tubes were found in the dolomite in the fault block forming the foot of the mountain at the east tip of the spur south of Galena Canyon (loc. F-89, NEV NEY see. 17, T. 22 N., R. 1 E.; fig. 9). Similar structures are present in the Noon- day Dolomite in the southern Nopah Range. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA The lower member of the Noonday Dolomite is a gran- ular recrystallized fine-grained dolomite mottled with spots of coarse-grained dolomite in euhedral grains (fig. 104). The spots of coarse-grained dolomite have quartz, evidently secondary, at their centers. Petro- graphically this rock resembles the thick-bedded dolo- mite in the underlying Crystal Spring Formation (fig. 8). The upper gray member of the Noonday Dolomite is coarser grained than the lower member; the grains are uniform in size, about 0.3 mm in diameter (fig. 102). Through the rock are numerous grains of euhedral mag- netite partially altered to hematite. In this area, as elsewhere in the region, the Noonday Dolomite contains small irregular deposits of lead min- erals; these have been prospected at numerous places along the mountaintop south and west of Galena Can- yon (table 5). So far as known, none of the deposits has been productive. Farther north in the Panamint Range, from Johnson Canyon northward to Tucki Mountain, a series of car- bonate rocks 1,000 feet or more thick, lying below the Johnnie Formation, is assigned questionably to the Noonday Dolomite. The formation seems to be at the stratigraphic position of the Noonday, but it is enough different lithologically to warrant further study to con- firm or correct the identification. The formation differs from the Noonday farther south in containing a great deal of limestone as well as dolomite and in having the dominant colors tan and white. In addition, there are beds of limestone conglomerate in which clasts of lime- stone 1-3 inches in diameter are contained in sandy dolomitic matrix. A. highly generalized section on the west side of Rogers Peak showed the following: Feet Top... Highly contorted thin-bedded limestone. White quartize. 100_____ White limestone. 250_____ Banded light and dark limestone. 250_____ Light-brown limestone. 250_.___ Limy sandstone. 200-____ Dark quartzite. 250_____ Banded light and dark limestone. Base. The Noonday(?) Dolomite seems to be equivalent to the series of dolomitic limestone on the west side of the range that Murphy (1932, p. 349) referred to as the Sentinel Dolomite (base), Radcliff Formation, and Red- lands Dolomitic Limestone (top). Johnson (1957, p. 370) correlated these beds with the Noonday. Table 5 lists the trace elements in eight samples from the Noonday Dolomite. In the southern part of the STRATIGRAPHY AND STRUCTURE A17 FIGURE 9.-Noonday Dolomite showing structures suggestive of Scolithus tubes. Location is at east foot of the mountain at the spur south of Galena Canyon. Panamint Range the dolomite is highly mineralized, notably with lead and zinc. The sample of light facies differs little from the dark one. A much larger number of samples would be needed to suggest whether the Noon- day (?) Dolomite should be correlated with the Noon- day. The trace element content of the Noonday(?) Dolomite is about the same as that of the limestone in the Kingston Peak(?) Formation in the northern part of the Panamint Range. JOHNNIE FORMATION The Johnnie Formation at its type locality, near the town of Johnnie about 50 miles east of Death Valley, is mostly shale and is 4,500 feet thick (Nolan, 1929, p. 461). A18 Microcrystalline dolomite FIGUR®K 10.-Micrographs of Noonday Dolomite. A, Lower member, a fine-grained dolomite mottled with coarse dolomite (D). Quartz grains (Q) occur at the center of some of the areas of coarse dolo- mite. B, Upper member, a medium-grained dolomite in which the grains are of uniform size and- contain scattered grains of magnetite (M). Diameter of field, 2.5 mm. In the Panamint Range, where it has been referred to as the Hanaupah Formation (Murphy, 1932, p. 349), it is mostly shale, and its thickness is more than 4,000 feet. The Johnnie Formation is conformable on the Noon- day Dolomite and is gradational with it, for the lower part of the formation consists of interbedded dolomite and quartzite. The contact is taken at the lowest quartzite, as has been done elsewhere (Hazzard, 19376, p. 303 ; Johnson, 1957, p. 373). In the southern part of the Panamint Range the lower third of the formation consists of interbedded dolomite and sandstone or quartzite. The dolomite is thin bedded and ripple marked. Some of the quartzite is conglomeratic with pebbles as much as 1 inch in diameter. The middle third of the formation is light-colored shale capped by dolomite; the upper third is purple shale with interbedded quartzite (fig. 11). A compos- ite section of the Johnnie Formation in the southern part of the Panamint Range is as follows: GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA TABLE 5.-Trace elements in the Noonday Dolomite Semiquantitative spectrographic analyses by Uteana Oda and E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] Northern part Southern part of Panamint Range of Panamint Range Noonday Dolomite Element Noonday(?) Dolomite Light | Dark dolo- | dolo- Prospects mite | mite A B C D E F G1 H: 200 15 15 | 10,000 | 3,000 50 20 50 200 | <200 | 5,000 | 3,000 8 700 nd nd 150 100 5 200 | 3,000 100 200 2, 000 7 10 7 7 T 10 200 20 <10 <10 <10 20 <10 10 500 <5 <5 7 7 7 7 7 100 <10 <10 <10 <10 <10 <10 <10 30 10 10 <10 <10 <20 <10 20 200 <10 <10 <10 <10 10 <10 20 50 <1 Te <1 <1 <1 <1 <1 5 >5 5 3 0. 2 0.5 >5 1 This sample also contained Ag, 70; Bi, 50; As, 1,500; Sb, >10,000. 2 This sample also contained Sc, 50. NotE.-Also found: Sn, <10; Ag, <1 (except sample G); Ge, <20; As <1,000 (except sample G); Sb, <200 (except sample G); In, <50; Cd, <50; Tl, <100; Ta <50; W, <50; La 50 or less; Se, <10 (except sample H). Composite section of Johnnie Formation in Siz Spring Canyon and Johnson Canyon Top. Base of Stirling Quartzite. Feet Purple shale member. Shale, mostly purple, some red, some green; fissile. Upper 100 ft includes interbedded quartzite and shale; beds transitional with overlying Stirling Quartzite. The purple shale contains fine sand grains 0.1 mm in diameter in sericitic matrix (fig. 12D) ; the quartzite interbedded with the shale near the top, of the member is fine grained (grains about 0.2 mm in diameter) with sericitic laminae and in a sericitic clay mati 202 2228 0 us nn asa T oice ain aas ence ade Yellow member. Olive-brown shale capped by yellow silicified dolomite about 25 ft thick in 1 or 2 beds ; dolo- mite contains thin beds of quartzite. The dolomite is very fine grained (0.01 mm) with vugs of coarser dolo- mite (0.1 mm) (fig. 120). The shale is sandy or silty with quartz grains in sericitic laminae (fig. 12B)_____. Dolomite member. Basal 200 ft consists of thin-bedded dolomite interbedded with ripple-marked sandstone, overlain by 35 ft of brown-weathering dolomite; upper 150 ft is well-bedded and thin-bedded quartzite and sandstone; at top is 5 ft of pebble conglomerate with pebbles as much as 1 in. in diameter. The dolomite is like that in the overlying yellow member but contains scattered quartz grains about 0.1 mm in diameter. The quartzite has rounded quartz grains with irregular sides due to recrystallization, and there is considerable as- sociated microcline; the qartz shows strain shadows; there is very little matrix around the grains (fig. 124) __ 500 400 Total thickness of Johnnie Formation-___________ 1, 400 STRATIGRAPHY AND STRUCTURE A19 FIGURB 11.-Johnnie Formation on the north side of Six Spring Canyon. Northward along the Panamint Range the Johnnie Formation thickens and the lithology changes. In Hanaupah Canyon and farther north the Johnnie For- mation is mostly shale. A section measured along the main (south) fork of Hanaupah Canyon is 2,300 feet thick, as follows: Section of Johnnie Formation in Hanaupah Canyon, from Narrows at west edge of Bennetts Well quadrangle to mine workings at end of road Top. Base of Stirling Quartzite. Feet 1. Quartzite, thin-bedded ; some argillite________________ 100 2. Limestone, interbedded with banded purple argillite___ _ 750 3. Argillite, purple; upper part banded 550 4. Argillite, weathers tan, greenish on fresh surfaces; contorted bedding... 175 5. Interbedded argillite, sandstone, and a few beds of thin- bedded, laminated, and highly micaceous dolomite; beds as much as/1 ft thick.________________________ 700 Dark beds forming the upper half of the hillside are the purple shale member; light beds in the middle and lower half are the shale member capped by dolomite. The hilltops are capped by Stirling Quartzite. Section of Johnnie Formation in Hanaupah Canyon, from Narrows at west edge of Bennetts Well quadrange to mine workings at end of road-Continued Feet 6. Interbedded dolomite and argillite; argillite greenish, weathers light tan ; dolomite beds 2 in to 1 ft thick; this is a transition zone between units 5 and the Noonday (?) - 50 Total thickness of Johnnie Formation-___________ 2, 825 Base. Top of Noonday(?) Dolomite, white or light- cream color; much altered ; no original structures left; 50 ft+ exposed. In the north fork of Hanaupah Canyon (Chuckwalla Canyon on the maps), there is a light-brown dolomite, about 200 feet thick, forming the top of the Johnnie. Below this is 50 feet of ripple-marked purple shale, and below this, 250 feet of fissile shale. The main part of the formation is argillite, as it is farther south. A20 s Microcrystalline dolomite Sericite containing silt-size quartz grains Clay, silty i C if Am 7 fil If} FicuUrE 12.-Micrographs of rock types from the Johnnie Formation. A, Quartzite from basal dolomitic member (Q, quartz with strain shadows; mi, microcline). Very little matrix between the grains. B, Shale from yellow shale member. C, Dolomite from top of the yellow shale member, mostly very fine grained dolomite but mottled with vugs filled with coarser dolomite (D). D, Sandy sericitic purple shale. Diameter of field, 2.5 mm. In Death Valley Canyon, dolomite at the top of the Johnnie Formation is white, but probably this color change is due to hydrothermal alteration. Light- colored dolomite was not seen elsewhere in the Johnnie Formation. At the head of Trail Canyon the Johnnie Formation is about 4,000 feet thick. The beds are in a much- faulted and steeply dipping monocline, and the stratig- raphy there is uncertain. The following is an approximate section : Feet Top-___Stirling Quartzite overlain by Wood Canyon For- mation. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA Feet 900.-___Dark shale. 350-___Brown quartzite like the Stirling, and perhaps this is the Stirling repeated by faulting. 900.____Dark shale. 900____Light-colored shale, green and tan. 350____Dark shale. 500.-___Brown shale. Base__Noonday(?) Dolomite. In the northern part of the Panamint Range the for- mation is mostly shale without evident marker beds of dolomite or coarse clastics. The thickness is uncertain on account of faulting and other deformation, but prob- ably it is 4,000 feet or more. Table 6 gives the results of analyses of trace elements in 18 samples from various rock types in the Johnnie Formation. Dolomite in the Johnnie Formation has about the same trace elements as does the Noonday Dol- omite, but it averages more zirconium. 'The shale has about the same trace elements as does the shale in the Kingston Peak(?) Formation in the northern part of the Panamint Range (table 4). STIRLING QUARTZITE At the mouth of Johnson Canyon and along both sides of Starvation Canyon, the Stirling Quartzite consists of three members. At the base is 700 feet of reddish-brown-weathering quartzite that is in part conglomeratic. About this is 500 feet of purple shale with thin beds of quartzite; at the top is brown- weathering quartzite 800 feet thick. This section is very similar to that in the Nopah Range (Hazzard, 1937b, p. 306-307). © The quartzites are vitreous; most of the beds are coarse grained. Pebbles in the conglomeratic layers are as much as 1 inch in diameter, but most are smaller, -¥» inch in diameter. The pebbles are mostly white quartz; a few are red jasper. There has been much recrystallization and quartz veining, and the beds are firmly indurated. Smooth surfaces show fine layering due to size sorting of the sediments; individual beds are cross-bedded (fig. 13) and many are ripple marked. Figure 14 is a micrograph of a thin section of the quartzite. Individual grains are subround and encased in see- ondary quartz. Both the original grain and the quartz deposited around it show strain shadows. Associated with the quartz is coarsely twinned microcline and some sericite. The rock is a true quartzite and breaks across the quartz grains. The purple shale separating the upper and lower quartzite members of the Stirling consists of fine- grained well-rounded quartz in laminae of sericite; it is similar to that in the Johnnie Formation (fig. 12). STRATIGRAPHY AND STRUCTURE TaBL® 6.-Trace elements in the Johnnie Formation A21 [Semiquantitative spectrographic analyses by Uteana Oda and E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] Shale or schist Dolo- Dolomite Element Chaos Conglomerate | mitic Dolomitic sand shale Dark Green Yellow 30 30 200 | 1,500 30 20 30 300 20 30 500 10 20 150 70 200 700 300 1 70 700 100 50 | 7,000 | 5,000 200 | 2,000 100 | 3,000 150 30 30 500 100 70 100 300 20 1 150 150 150 5 30 7 500 200 100 200 200 700 150 700 10 700 300 100 10 70 10 70 20 50 50 30 20 5 5 150 50 10 <5 <5 10 <10 15 10 <10 <10 <10 <10 10 20 15 <10 <10 <10 <10 150 100 50 70 100 500 20 30 20 200 100 20 10 10 10 30 20 20 20 20 150 <10 10 10 100 20 10 <10 <10 <10 3 2 2 1 <1 <1 <1 1 <3 <1 <1 <1 <1 7,000 | 7,000 | 2,000 | 5,000 | 5,000 >10,000 | 2,000 | 10,000 200 | 10,000 | 3,000 300 70 | 3,000 200 70 70 30 70 50 15 <10 50 20 <10 <10 <10 <10 20 15 10 15 15 50 <10 <10 <10 50 10 <10 <10 <10 <10 50 50 20 50 50 <20 5 <5 <20 <20 20 <20 <5 <5 <5 150 70 50 70 100 700 20 30 20 500 70 20 5 5 700 500 300 500 500 7, 000 300 500 50 | 2,000 500 100 15 70 20 30 20 20 30 1, 000 20 <20 200 | 2,000 <20 100 500 50 70 1 2 1.5 1 1 0.2 0.5 >5 >5 0.5 >5 0.5 5 >5 NotE.-Also found: Zn, <200; La, <50; Mo, <2; Ag, <1; Bi, <5; Sn, <10; As, <500; Sb, <50; W, <20; Nb, <10. In places, there are some thin beds of shale and dolo- mite about 30-50 feet below the top of the formation. These beds are like those in the lower part of the Wood Canyon Formation. F1GURE 13.-Detail of bedding in Stirling Quartzite at mouth of Johnson Canyon. Beds are 3-12 inches thick. FIGURE 14.-Micrograph of Stirling Quartzite. The grains of quartz (Q) are rounded but also ir- regularly intergrown. Strain shadows conspic- uous under cross nicols. Between the large grains is secondary quartz. In most beds seri- citized feldspar and some muscovite occurs with the quarts grains. Diameter of field, 2.5 mm. Trace elements in 9 samples of the Stirling Quartzite are given in table 7. Trace elements in the quartzite and shale facies are like those in the conglomerate and shale, respectively, of the Johnnie Formation (table 6). The quartzite differs from that of the Kingston Peak(?) Formation in the Panamint Range (table 4) in having less copper, barium, and strontium. The quartz veins in the Stirling contain trace elements only in small amounts compared to the parent quartzite. In the Death Valley area the Stirling Quartzite has a maximum thickness of about 2,000 feet. At the type locality in the Spring Mountains (Nolan, 1929, p. 463) it is 3,700 feet thick. The boundaries of the formation, as shown on the geologic map of the Panamint Range (pl. 1), imply considerable variation in thickness of the A22 TaBLE 7.-Trace elements in the Stirling Quartzite [Semiquantitative spectrographic analyses by Uteana Oda and E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] Quartz vein Quartzite Shale bed Element Clear | White A B C D E! F G H I 100 10 10 10 10 20 10 300 700 50 70 100 15 50 150 100 50 100 2 5 150 200 2, 000 300 1, 500 10 100 10 20 10 20 100 5 <10 10 <10 <10 15 <10 <10 15 20 20 200 <10 10 10 10 150 50 100 | <10 <10 <1 <1 <1 1.5 <1 <1 500 | 1,500 |>10,000 | 7,000 |>10, 000 30 500 20 15 150 200 10 20 <10 <10 70 <10 50 <10 <10 <5 <20 <20 <20 <20 <5 <5 15 10 300 30 300 <5 5 500 300 1, 500 | 1,000 2, 000 30 100 50 20 100 50 50 | <20 <20 0.2 | 0.15 1 1 2 | 0.02 0.1 ! La, 100; Mo, 15; sample E is from the base of the upper plate of the Amargosa thrust fault and has been hydrothermally altered. NotE.-Also found La,<50 (except sample E); Mo <2 (except sample E) Ag, <1; Bi,<5; Sn,<10; As, <500; Sb, <50; W, <20; Nb, <10. quartzite; but this variation is attributable to lack of consistency in picking the boundary between the Stir- ling and overlying Wood Canyon Formation, the basal part of which also is quartzitic. It is difficult to dis- tinguish the Stirling Quartzite from the thin-bedded quartzites that are included in the lower part of the Wood Canyon Formation, especially where there is granulation of the quartzite along faults. The Stirling Quartzite coincides with a surface of flat faulting at its type locality (Nolan, 1929, p. 463, 470), and in the Funeral Mountains and Panamint Range. In the Funeral Mountains the flat fault is ex- posed at Echo Mountain and from Hells Gate to Day- light Pass. In the Panamint Range the Stirling Quartzite forms the base of the upper plate of the fault at the mouth of Mosaic Canyon and the top of the lower plate in Tucki Wash along the south and east sides of the Tucki Mountain thrust. As a result of this and other faulting, the Stirling Quartzite locally is absent, but such absence is attributable to deformation and not to stratigraphic thinning. Similarly, no stratigraphic significance can be placed on the variations in thickness that can be observed in short distances within this area. The thinning from the type area to the Nopah Range and westward to the Panamint Range may be real, be- cause this thinning is accompanied by an increase in shale and thinner bedding westward in the formation. CAMBRIAN SYSTEM About 8,500 feet of beds representing all parts of the Cambrian System are present in the Death Valley re- gion. These include the Wood Canyon Formation of Early Cambrian and Early Cambrian(?) age, the Za- GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA briskie Quartzite of Early Cambrian age, the Carrara Formation of Early and Middle Cambrian age, the Bonanza King Formation of Middle and Late Cambrian age, and the Nopazh Formation of Late Cambrian age. The oldest beds in the Death Valley region contain- ing animal remains are in the Wood Canyon Formation. The top of the Cambrian System lies somewhere near the top of the Nopah Formation, but it cannot be lo- cated more precisely because of the lack of fossils in this part of the section. For mapping, the upper and lower boundaries of the Cambrian System are placed at the formation boundaries. wooOD CANYON FORMATION The Wood Canyon Formation of Early Cambrian and Early Cambrian(?) ago conformably overlies the Stirling Quartzite of Precambrian age, both at the type locality in the Spring Mountains (Nolan, 1929, p. 463) and in the mountains adjoining Death Valley. The top of the Wood Canyon in Death Valley is taken at the base of the Zabriskie Quartzite. At the type locality the top of the Wood Canyon Formation is at the base of a 20-foot bed of white quartzite which probably is equivalent to the Zabriskie (Hazzard, 19376, p. 313). In the Nopah Range the Zabriskie Quartzite has been included as a member in the Wood Canyon Formation together with 630 feet of overlying beds (Hazzard, 193%b, p. 310). In this report the beds overlying the Zabriskie Quartzite are treated separately as part of the Carrara Formation. The basal unit of the Wood Canyon Formation, about 465 feet thick, consists mostly of thin-bedded quartzite, but contains considerable shale and dolomite. Above this is 1,200 feet of quartzite in thicker beds. No fos- sils other than possible ScolitAus tubes and possible algal structures have been found in the lower part of the for- mation in Death Valley or in the surrounding regions. The upper member of the Wood Canyon Formation, about 900 feet thick, consists of shaly and dolomitic beds as well as thin beds of siltstone and quartzite (fig. 15). Fossils found in this member include fragmentary trilo- bites representing Nevadella gracile (Walcott), inde- terminate molds of brachiopods, and molds of cystid plates in a unit of thin sandstones that generally lies just below a zone of oolitic and pelmatazoan dolomites and limestones. Thin sections of some of these pelmat- azoan limestones in Death Valley and at Daylight Pass show the presence of fragmentary archaeocyathids. The association of sandstones with fragmentary trilo- bites and brachiopods and oolitic and pelmatazoan car- bonates characterizes the upper part of the Wood Canyon Formation throughout the Death Valley region and as far north as the Groom district in Nevada (Palmer, oral commun., 1961). ¥ Write" L. _ 2) 15.-Detail of interbedded shale, quartzite, and dolomite in the upper part of the Wood Canyon Formation in the ridge along the north side of Blackwater Wash. The thick bed in the upper right is dolomite; below this is quartzite and shale. Collections from these beds in Death Valley were studied by A. R. Palmer, who has reported on them as follows (locations are indicated on the geologic map) : F-31. Above Quartzite Spring, north side of Starvation Canyon, Bennetts Well quad. (NW sec. 12, T. 21 S., 46 E.) "Olenellid scraps; certainly Early Cambrian age, but species not determinable." F-64 (310;-CO). 1.5 miles south of Panamint Burro Spring; same general fault block as F-31, Bennetts Well quad. (2,000 ft north of NW cor. sec. 1, T. 21 S., R. 46 E.), estimated 500 ft below the Zabriskie Quartzite. "Nevadelle gracile? (Walcott) ." F-36. Southeast side Hanaupah Canyon, alt 3,100 ft, 2 miles above mouth of Canyon. Bennetts Well quad. "Olenellid scraps, certainly Early Cambrian in age, but species not identifiable." F-29 (24}53-CO). East base of west butte of the Death Valley Buttes, Stovepipe Wells quad. (2,500 ft northeast of NE cor. sec. 36, T. 14 S., R. 45 E.). Pelmatazoan calcarenite. Indeter- minate archaeocyathid. F-50. Base of Zabriskie Quartzite in Blackwater Wash, top of hill 951, west side Furnace Creek quad. "Kutorgina? sp." A. section of the Wood Canyon Formation, measured along the north side of Blackwater Wash (Furnace Creek quad.) follows: A23 Bection of Wood Canyon Formation along north side of Blackwater Wash [Measured by Charles B. Hunt, A. R. Palmer, and R. J. Ross, Jr.] Top. Base of Zabriskie Quartzite. 1. Brown-weathering dolomite and quartzite, some green- ish shale. Dolomite and quartize beds 1-10 ft thick; shale beds less than 1 ft thick (fig 15). Dolomite cross- bedded, in part strikingly oolitic. Tubes suggestive of Scolithus tubes about 200 ft above the base__________- 2. Shaly member. Lower 70 ft mostly green siltstone interbedded with dark-weathering quartzite in beds 5 ft thick. Overlying this is 210 ft of siltstone that is red- dish along shear zones but greenish away from them. Above this is 105 ft of dark-weathering quartzite; 35 ft of green shale and siltstone, and, at the top, 100 ft of greenish micaceous fine-grained quartzite and silt- stone. Some tubes suggestive of Scolithus in the up- permost unit___. a 3. Quartzite member. Beds 1-3 ft thick; light gray on fresh fracture but weathers dark. Micaceous. Num- erous gritty beds; some conglomeratic with pebbles as much as % in. in diameter; most of these are milky quartz; some are red jasper. Lower 200 ft includes much grit and numerous shale beds about 1 ft thick; purple and green; increasing amount of shale down- ward. Two hundred feet above base is 50-ft bed of grit and conglomerate. Upper 700 ft is mostly fine-grained quartzite. This unit of section crossed by some faults and thickness is uncertain, estimate_________________- 1, 200 4. Quartzite with interbedded shale, fine-grained, thin- bedded, transitional between units 3 and 5-_________- 5. Quartzite with interbedded siltstone and some fine- grained thin-bedded shale; a few thin beds of brown- weathering dolomite, light brown on fresh surfaces. Eighty feet above base is 10-ft bed of gray dolomite overlain by 15 ft of light-tan thin-bedded dolomite. Quartzite is light brown, weathers dark brown; mica- ceous. Twenty feet below top is a thin bed of dolomite having floating sand grains and pebbles of carbonate rock; intraformational conglomerate________________- 6. Shale and quartzite. Quartzite beds are 1-12 in. thick, finely laminated, micaceous, light brown on fresh sur- faces, reddish brown on weathered surfaces. Shale is olive green on weathered surface ; also micaceous._. 7. Shale, sandstone, and dolomite. Shale and sandstone green and brown; dolomite dark blue on fresh sur- face; weathers brown. Dolomite beds 1-2 ft thick. Feet 400 520 120 150 130 @R Total thickness of Wood Canyon Formation-__. 2, 585 Base. Top of Stirling Quartzite. Contact gradational and taken at top of highest massive light-colored quartz- ite. There are thin beds of shale and dolomite 30-50 ft below the contact. Thin sections of the quartzite and shale beds of the Wood Canyon Formation are illustrated on figure 16. The shale contains muscovite (or sericite) and magnetite in addition to minute quartz grains that occur both scattered and in layers. The quartzite has interlocking gmme: A24 Quartz grains Muscovite flakes C {Pes y { 5 moat 1% 9. has o" \- ___} se» > Quartz grains Muscovite flakes B Quartz Silt and clay matrix A Magnetite Fisurm 16.-Micrographs of rock types in the Wood Canyon Forma- tion. A, Quartzite from basal member. Other quartzite has much less interstitial material and resembles the Stirling Quartzite. B, Shale composed largely of silt and clay. C, Shale composed largely of muscovite and sand grains. Diameter of field, 2.5 mm. TaBu® 8.-Trace elements in the Wood Canyon Formation. [Semiquantitative spectrographic analyses by Uteana Oda and E. F. Cooley, U. S. Geol. Survey. Values in parts per million, except Mg, which is given in percent.] Wood Canyon Formation Dolo- Ele- mitic ment quartz- Lime- Shale Sandy shale Quartzite ite stone 20 150 20 20 10 15 | 100 70 50 10 10 10, 000 |2, 000 15 |7,000 12,000 | 150 |1,000 |1,000 | 150 [1,500 |<10,000 30 3 3 30 | 200 30 5 5 20 50 30 12,000 70 | 100 30 | 200 | 150 | 300 | 100 | 200 15 7 30 | <5 50 20 70 7 5 7 5 <5 <10 10 | <10 10 10 20 | <10 | <10 | <10 | <10 <10 15 30 | <10 10 10 | 100 30 20 50 15 10 10 70 | <10 30 20 30 10 30 10 50 20 <1 1 5 1 1 1 2 1 <1 <1 <1 1, 500 [7,000 | 300 |1, 500 |1,000 |7,000 [1,500 |1, 500 |1, 500 (2,000 700 10 50 20 15 15 50 70 20 20 20 <10 <10 15 10 | <10 10 | <10 | <10 | <10 | <10 10 <10 7 10 10 5 10 8 5 10 5 <20 30 70 5 10 15 | 100 20 20 10 20 10 150 | 150 | 500 | 200 | 100 | 500 [1,000 | 7oo | 500 | 700 100 100 | 100 | 700 50 | 200 50 11, 5 70 20 50 500 5 3 | 0.2) 0.7 0.7 2 | 0.5 | 0.2] 0.5 | 0.3 5 NotE.-Also found: La, 50; Mo, 2; Ag, 1; Bi, 5; Sn, 10; As, 500; Sb, 50; W, 20; Nb,10. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA grains of quartz with associated magnetite and traces of mica. Trace element concentrations in quartzite in the Wood Canyon Formation (table 8) are about the same as in the Stirling Quartzite (table 7), except that the Wood Canyon quartzite averages higher in manganese. A comparison of shales in the Wood Canyon Formation and in the Johnnie shows that the Wood Canyon con- tains more manganese and less vanadium, boron, gal- lium, and barium than does the Johnnie. The propor- tions of trace elements in the limestone are quite different from the proportions in dolomite in the Johnnie Formation (table 6). ZABRISKIE QUARTZITE The Zabriskie Quartzite, originally named and de- scribed as a member of the Wood Canyon Formation by Hazzard (1937b, p. 309), consists of white quartzite in laminated beds about 6 inches to 2 feet thick inter- bedded with micaceous purple shale, sandstone, and siltstone. The quartzite beds show little crossbedding; mostly they are evenly laminated. The quartzite con- tains few impurities; the rock consists of closely inter- locked grains of quartz with little other foreign mat- ter (fig. 17). The Zabriskie Quartzite, like the Stirling Quartzite, has been subject to major deformation due to shearing along flat faults that approximately parallel the bed- ding. As a consequence the formation varies greatly in thickness, but the variation is attributable to tectonic deformation-not to stratigraphic changes. Along the north side of Blackwater Wash, the Za- briskie Quartzite is 160 feet thick and is mostly massive 17.-Micrograph of the Zabriskie Quartzite. The rock consists of closely interlocked grains of quartz with almost no interstitial material. Quartz grains are rounded but show signs of irregular intergrowth. Diameter of field, 2.5 mm. STRATIGRAPHY AND brecciated quartzite stained lavender. Fifty-five feet below the top is a 2-foot layer of mustard-colored shale and siltstone. A thickness of 70 feet has been reported for the Za- briskie Quartzite at Aguereberry Point; gray quartzite just below the base of the Zabriskie contains rodlike structures several inches long oriented perpendicular to the bedding, possibly Scoli¢tAhus tubes (Hopper, 1947, p. 406). In the Funeral Mountains, north of Echo Canyon and at the east edge of the Furnace Creek quadrangle, the Zabriskie Quartzite is several hundred feet thick, mostly quartzite breccia. About a hundred feet of undis- turbed beds at the top showed the following section : Section of Zabriskie Quartzite north side of Echo Canyon center north side NW, sec. 15, T. 27 N., R. 2 HE. Feet Top. Base of Carrara Formation, 1. Quartzite; interbedded white, black, and reddish beds 6 in to 2 ft thick, evenly laminated, not much cross- bedding raido nts ae aand an wig 45 2. Shale, siltstone, and sandstone, purple, micaceous____. 6 8. Quartzite, white, vitreous; in beds 1 ft thick ; grains as much as 1 mm Ne s 42 4. Tectonically crushed quartzite______________________ Total thickness uncertain because of brecciation and faulting. Base. Wood Canyon Formation. Five samples of Zabriskie Quartzite analyzed for trace elements contain similar amounts of the several elements (table 9). The quantities are very much less than in the Stirling Quartzite (table 7), but the propor- tions appear not to be greatly different. A block of sheared granulated quartzite surrounded by volcanic rocks near the north end of the Artists Drive fault blocks is represented by the two samples F and G in table 9. The quartzite probably is the Zabris- kie, but it could be the Eureka (table 13). Its low con- tent of trace elements makes it unlike any of the known Precambrian quartzites. The Zabriskie Quartzite is considered Early Cam- brian in age. J CARRARA FORMATION The Carrara Formation was named by Cornwall and Kleinhampl (1962) for exposures at Bare Mountain, Nev., just north of Death Valley. The Carrara Forma- tion represents a sequence of beds transitional between the underlying clastic formations (Zabriskie Quartzite and Wood Canyon Formation) and the overlying car- bonate ones (Bonanza King and younger formations). The Carrara is widespread in the Death Valley region where it is characterized by an alternation of shaly or 7176-623 O-66-3 STRUCTURE A25 TaBu® 9.-Trace elements in the Zabriskie Quartzite [Semiquantitative spectrographic analyses by Uteana Oda and E. F. Cooley, U.S. Geol. Survey. - Values in parts per million, except Mg, which is given in percent] Funeral | Fault block in Panamint Range Moun- | volcanics at north tains end of Artists Element Drive A B C D E F G 10 | :«<10 | <10 j «<10 | «<10 30 <10 100 20 10 10 20 10 10 8 100 5 3 5 3 20 AT.: . sina. 200 200 70 50 70 50 20 Ni...... 5 5 5 5 5 <5 CO i-~ki..c 10 | «10 {:< 10 {-«10 { «10 | «10 <10 \ een <10 10 |~«<10 |'<«10 | «10 10 <10 esas |! «10 | «10 | <10. | <10 | «10 <<10 Be..-:..... <1 B >5 6 NoTE.-Also found: Sn,<10; Ag, < 1; Ge, <20; As, <1,000; Sb,<200; In, <50; Cd, <50; Tl, <100; Ta, <50; W, <50. NOPAH FORMATION The Nopah Formation at the type locality in the Nopah Range is 1,740 feet thick (Hazzard, 1937h, p. 276, 320) and consists of a basal shaly member about 100 feet thick overlain by alternating light- and dark- gray dolomites. In the northern Panamint Range the sequence of lithologies is similar to that in the Nopah Range, and the thickness is about 1,600 feet (McAl- lister, 1952, p. 9; 1955, p. 10; 1956). At both locations fossils indicative of Late Cambrian age occur in shaly beds at the base of the formation. Indeterminate gas- tropods of possible latest Cambrian age have been found in the upper 700 feet of the Nopah Formation in the Amargosa Range and in the northern Panamint Range (McAllister, 1952, p. 10). The Nopah Formation is correlated with the Cornfield Springs Formation in the Providence Mountains (Palmer, 1956, p. 673). The Nopah Formation in the mountains bordering Death Valley is very similar lithologically to that at A30 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA Fisurs 22.-Thin-bedded middle member of the Bonanza King Formation on the north side of Trail Canyon, view north. This member, about 600 feet thick, forms a distinctive unit separating massive thick-bedded dolomite comprising the upper and lower members of the formation. the type section and in the northern Panamint Range, and the characteristic fossils occur in the shaly beds at the base (fig. 23). The formation is about 1,500 feet thick in the Funeral Mountains, but it appears to be somewhat thinner in Tucki Mountain and in the south- ern part of the Panamint Range. Several computed thicknesses average about 1,200 feet. Sections through the whole formation and through the characteristic basal shale member are given below. Figure 24 is a view of the banded light- and dark- colored dolomite forming most of *the Nopah Forma- tion. Much of this dolomite is c- 7, the chert occur- ring as nodules distributed along bedding planes and as irregular lumps that seem to have little or no relation to the bedding. Figure 20 shows some micrographs of the light dolomite and of the dark dolomite and chert. A section of the Nopah Formation measured in Trail Canyon follows. Cale on06 I 000% Figur» 23.-Bioclastic bed with fragments of trilobites and brachiopods from shale unit at base of Nopah Formation (colln. F-54-3098-CO). Section of Nopah Formation, north side of Trail Canyon 2 miles above the canyon mouth [Section measured by Charles B. Hunt and A. R. Palmer] Top. Base of Pogonip Group. 1. Dolomite, black, thick-bedded______________________ 2. Dolomite. gray, in thick beds___-________________ ___ 8. Dolomite, black, masgive.___.______-________________ 4. Dolomite, light-colored__-- 5. Dolomite, black, masgive___________________________ 6 T 8. 9 Dolomite. . Dolomite, banded black and light-colored . Dolomite, light-colored, thin-bedded___________--__-- Dolomite. DIACK, MARSIYVEL ___ _._. -. Feet To 275 50 120 T5 110 85 60 60 Section of Nopah Formation, north side of Trail Canyon 2 miles above the canyon mouth-Continued 10. Dolomite, light-colored, thin-bedded, forms slope-___. 11. Shale and limestone. Shale greenish or brown in beds 1-4 ft thick; some shale has nodules of lime- stone. Limestones brown and in beds 6 in to 2 ft thick. Many are trilobite breccias; others are echinoderm breccias. Linguloid brachiopods in the. Shalo.... 2 lll. aos mn Colln. F-68, (3143-CO), top of unit: Cheilocephalus sp. Undetermined dokimocephalinid Feet 110 T5 A32 Section of Nopah Formation, north side of Trail Canyon 2 miles above the canyon mouth-Continued 11. Shale and limestone-Continued Colln. F-67, (3142-CO), 20 ft below top of unit : Apachia sp. Undetermined pterocephalinid Colln. F-66, (3141-CO), at base of unit : Homagnostus obesus (Belt) Strigambitus utahensis (Resser) Dunderbergia variagranula Palmer Apsotreta sp. Dysoristus sp. 12. Concealed . Feet o nes 25 Total thickness of Nopah Formation.______________ 1, 120 Base. Thick-bedded dolomite, top of Bonanza King Formation. Section of shale member at base of Nopah Formation, east side of mouth of Grotto Canyon, NEV, NEV sec. 8, T. 16 S., R. J5 B.; alt. 1.175 ft Top. Thick-bedded dolomite of Nopah Formation. Thin-bedded limestone and tan shale. Shale mostly in laminae separating thin beds of limestone, but some shale beds are 10 ft thick. Basal 15 ft is brown lime- stone; higher ones blue gray, in beds 1 in to 2 ft thick. Nodular limestone and shale 40 ft above base_________ 115 Colln. F-69 (3144-CO) top of unit: Elburgia quinnensis (Resser) Sigmocheilus sp. Cheilocephalus brachyops? Apachia sp. Colln F-1 (24383-CO), near middle of unit: Elburgia quinnensis (Resser) Cheilocephalus sp. Strigambitus? blepharina Palmer Homagnostus sp. Morosa brevispina Palmer Colln. F-71 (3146-CO), 15 ft above base of unit; Dunderbergia variagranule Palmer strigambitus utahensis (Resser) Homagnostus sp. Colln. F-70 (3145-CO), basal limestone of unit: Minupeltis conservator Palmer Cernuolimbus granulosus Palmer Pseudagnostus sp. Base. Massive dolomite at top of Bonanza King For- mation. Feet Palmer Rection of shale member at base of Nopah Formation, south side Echo Canyon one-half mile above the canyon mouth [Measured by Charles B. Hunt, A. R. Palmer, and R. J. Ross, Jr.] Top. Base of lowest cliff-forming dolomite in Nopah For- mation. 1. Limestone, dark-brown to black; in beds 1 ft thick; - Feet cherty Poe % 15 Colln. F-82, (3147-CO), from top of unit: Pterocephalia? punctata Palmer Pseudagnostus sp. "Acrotreta" spinosa Walcott GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA RBection of shale member at base of Nopah Formation, south side Echo Canyon one-half mile above the canyon mouth-Con. Feet 2. Shale, tan, limy ; in part sandy-_._________i_________ 45 Colln. F-54, (3098-CO), 15-25 ft above base of unit: Elburgia quinnensis? (Resser) Atrigambitus? blepharina Palmer Apsotreta sp. 3. Limestone pebble conglomerate and coarse bioclastic beds; some limestone beds % in thick; some silt beds: 4 -in thick ; 50 4. Covered - 50 Potal - thickness Ll __ 160 Base. tion. Massive dolomite, top of Bonanza King Forma- Two other collections of fossils from the Nopah For- mation were reported upon by Palmer as follows: F-53 ($103-CO0). North side of Echo Canyon, % mile above mouth, Furnace Creek quad. (SW sec. 16, T. 27 N., R. 2 E.). "Apsotreta sp.; abundant siliceous sponge spicules, a part of 'this collection is essentially a spiculite." F-58 (8089-C0). Ridgetop south of Echo Canyon about 1 mile above the mouth of the canyon, alt 2,950 ft, Furnace Creek quad., probably near middle of the shale unit sec. 15, T. 27 N., R. 2 E.). "Hlburgic quinnensis (Resser) ; Pseudagnostus communis (Hall and Whitfield) ; Homagnostus tumidosus (Hall and Whitfield) ; Morosa brevispina Palmer ; Atrigambitus? blepharina Palmer; Apsotreta sp.; 'Acrotreta' spinosa Walcott ; conodont." Trace elements in the Nopah Formation are listed in table 12. The samples from the Funeral Mountains are limestone from the base of the formation ; those from Tasug 12.-Trace elements in the Nopah Formation Semiquantitative spectrographic analyses by Uteana Oda and E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] Panamint Range Funeral Mountains Element Dolomite Limestone <10 70 20 10 10 MN.. ;... 10 50 70 700 1, 000 CUS 2 5 50 5 2 TT <10 70 <10 <10 20 5 5 <5 5 5 5 >5 0.7 0. 7 NotE.-Also found: Sn, <10; Ag, <1; Ge, <20; As, <1,000; Sb, <200; In, <50; Cd, <50; Tl, <100; Ta, <50; W, <50; Nb, <10. STRATIGRAPHY AND STRUCTURE A33 the Panamint Range are dolomite from the upper part of the formation. Whereas limestone and dolomite in the Bonanza King Formation have about the same con- tent of trace elements (table 11) , the limestone and dolo- mite of the Nopah Formation have quite different pro- portions of some constituents; notably, manganese, ti- tanium, barium, and strontium are very much more abundant in the limestone than in the dolomite. Dolo- mite in the Nopah Formation has about the same amount and proportions of trace elements as does the dolomite in the Bonanza King Formation. ORDOVICIAN SYSTEM POGONIP GROUP The name Pogonip originally was applied to the con- siderable thickness of carbonate rocks lying above quartzite of Cambrian age and extending up to the Eureka Quartzite of Ordovician age (King, 1878, p. 188). The name has been redefined several times and now is restricted to rocks of Ordovician age ; underlying rocks of Cambrian age now are separated from the Pogonip (Hazzard, 1937b; Hintze, 1949, 1951; Easton and others, 1953; McAllister, 1952; Nolan, Merriam, and Williams, 1956). In the Death Valley area the Pogonip Group overlies the Nopah Formation and is overlain by the Eureka Quartzite. According to Ross (oral commun., 1961) the Pogonip Group of this area probably is roughly equivalent to the Yellow Hill and Tank Hill Limestones of the Pioche district (Westgate and Knopf, 1932, p. 14). In the Death Valley area the Pogonip Group is about 1,500 feet thick. In Trail Canyon it is composed of three distinct members. The lower member consists of thin- bedded dolomite, the upper of thick-bedded dolomite; the middle member is shaly (fig. 24). Very little lime- stone is found in this section, and there seems to be evi- dence of a considerable amount of secondary dolomitiza- tion, which makes comparison with measured sections in other areas difficult. In the northern part of Tucki Mountain the Pogonip may be represented in a limestone facies, but outcrops are in disjointed fault slices which make stratigraphic placement almost impossible. Figur 24.-View of Pogonip Group in Trail Canyon. View is north. At left is light- and dark-colored dolomite of the Nopah Formation (€n). Thin-bedded dolomite and shale (ds) in the lower and middle part of the Pogonip Group form the saddle; thick-bedded dolomite (do) in the upper part of the Pogonip forms the dark ridge dipping under the light-colored Eureka Quartzite (Oe) at the right. Hill at extreme right is capped with Tertiary lavas (T) ; at the base of the hill is dark Ely Springs Dolomite (Oes). A34 A. threefold division of the Pogonip is possible in sev- eral nearby areas; the three subdivisions according to Ross (oral commun., 1961), are roughly equivalent to the shaly limestones of the Goodwin Formation, over- lain by the limy shales of the Ninemile Formation, which, in turn, are overlain by the more massive lime- stones of the Antelope Valley Limestone, all of the cen- tral Nevada Eureka district (Nolan and others, 1956, p. 24-25). Hazzard (1987b, p. 276) has recognized a similar tripartite division of the Pogonip Group in the Nopah Range. Similar subdivisions have been reported in the northern part of the Panamint Range by Mc- Allister (1952, p. 11), and at Bare Mountain to the north of Death Valley (Cornwall and Kleinhampl, 1962), as well as in the general area of the Nevada Test Site farther to the east. In the Death Valley area the basal unit of the Pogonip Group is mostly dolomite; but this may be due to meta- morphism, because this member elsewhere includes con- siderable limestone. In adjacent areas it is mostly lime- stone. The middle unit of the Pogonip Group in the Dolomite darkened with organic matter maz I -Z Clear dolomite Fieurm 25.-Micrographs of rocks from Ordovician formations. A, Dolomite, with chert, from upper unit of Pogonip Group. B, Eureka Quartzite. C, Ely Springs Dolomite. Diameter of fields, 2.5 mm. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA Death Valley area is reddish; this probably also is at- tributable to metamorphism, because relict sedimentary structures, such as intraformational conglomerate, coarse bioclastic beds, and occasional crossbedding in calcarenites, can be found. Also, numerous dikes cut the Pogonip Group from south of Trail Canyon to Blackwater Wash. Figure 254 is a micrograph of dolomite from the Pogonip Group. No fossils were found in the lower and middle parts of the Pogonip Group, but the cliff-forming dolomite comprising the upper third of the formation at many places contains large gastropods in such abundance as to be a lithologic guide to the dolomite (fig. 26). Fossils from the Pogonip Group were collected at 10 localities in the Death Valley area, as follows: F-3 (D643-CO). Dolomite in upper part of Pogonip Group; south side of canyon north of Trail Canyon, Furnace Creek quad.; 2.1 miles west and 0.3 mile north of SW% see. 31, T. 18 S., R. 47 E., alt 1,280 ft. Identifications by R. J. Ross, Jr., Receptaculites? sp.: Palliseria? sp. Probably high Pogonip and equivalent to the Antelope Valley Limestone of the Eureka area, Nevada." F-5 (not cataloged). Dolomite, upper part of Pogonip Group, north base of Tucki Mountain below mouth of Trellis Canyon, Stovepipe Wells quad. (SE4% SE% see. 23, T. 16 S., R. 45 E., alt 1,280 ft). Identification by E. L. Yochelson, "The material consists of two pieces of dark-gray dolomite showing poor cross sections of three gastropods; one saw cut to determine the third dimensions shows a profile suggestive of Palliseria, a guide to the Antelope Valley Limestone of central Nevada." F-13 (D645-CO). Dolomite in upper part of Pogonip Group, north side of Trail Canyon, alt 1,600 ft, Furnace Creek quad. Identification by R. J. Ross, Jr., "Palliseria sp." F-27 (D641-CO). Dolomite in upper part of Pogonip Group, north side of second ridge south of the mouth of Trail Canyon, alt 1,600 ft, Furnace Creek quad. Identification by R. J. Ross, Jr., "Probably Palliseria." F-28 (D642-CO). Same as F-27, lower in gulch, alt about 1,500 ft. Identification by R. J. Ross, Jr., "Receptaculites sp., Palliseria sp. Unquestionably high Pogonip." F-4;0 (3626-CO). Pogonip Group at flat fault 1% miles south of Trail Canyon, 1.2 miles east of hill 4889, Furnace Creek quad. Identification by E. L. Yochelson, "Cross section of sponge?; Maclurites sp. indet.; Palliseria robuste Wilson. Palliseria Robusta, confined to the second oldest faunal zone in the Antelope Valley Limestone of central Nevada, is a guide to early Middle Ordovician age." F-,2 (D587-CO). Fault block under Eureka Quartzite, 1% miles south of Trail Canyon, alt 1,000 ft, Furnace Creek quad. (7,500 ft south of west of SW cor. sec. 7, T. 19 S., R. 47 E.). Identification by R. J. Ross, Jr., "Very poorly preserved gas- tropods and trilobite fragments. None can be identified. Small brachiopod species suggests Diparelasma; it and the lithology suggest Pogonip." F-43 (D588-CO). 1,000 ft northeast of F-42 and apparently overlying it. Identification by R. J. Ross, Jr., Unidentifiable gastropods; abundant @irvanella? Age indeterminate." F-)? (8625-CO). 1%, miles southwest of "Dinosaur," 2% miles southwest of SW cor. sec. 6, T. 18 S., R. 47 E. At south base of hill 430, Furnace Creek quad. Identification by E. L. Yoch- pgreene STRATIGRAPHY Ficur® 26.-Large gastropods (Palliseria sp.) in dolomite in upper part of the Pogonip Group. elson, "Receptaculites sp., Maclurites, incomplete but sug- gestive of M. magnus; Palliseria robusta Wilson. The Pal- liseria is guide to early Middle Ordovician (see comment for F-40)." Also in this collection, according to R. J. Ross, Jr., is Syntrophopsis? sp. Colln. F-61 (D589-CO). From fault block, probably Pogonip Group, in Red Amphitheater breccia at mouth of second can- yon south of Echo Canyon, Furnace Creek quad. (Center, east side, sec. 21, T. 27 N., R. 2 E.). According A. R. Palmer, "This collection contains orthoid brachiopods, gastropod cross sections, and an asaphid trilobite pygidium which collectively indicate an Ordovician age." According to R. J. Ross, Jr., "The trilobite segments are very characteristic of Ordovician proparian types, and a few brachiopod outlines suggest Anomalorthis." Fossils collected in the Funeral Mountains (C. A. Richards *), in the Panamint Range (McAllister, 1952, p. 11; 1956), in the Nopah Range (Hazzard, 19376, p. 276) and on the Nevada Test Site (Johnson and Hib- bard, 1957, p. 346-347) indicate that the upper dolo- * Richards, C. A., 1959, Geology of part of the Funeral Mountains : Unpub. manuscript on file at Death Valley Natl. Monument and Univ. Southern California. AND STRUCTURE A35 mitic unit in the Death Valley area correlates with the Antelope Valley Limestone. The Pogonip Group is considered to be Early and Middle Ordovician in age. In the Death Valley area the contact between the Pogonip Group and Eureka Quartzite appears to be gradational for it is marked by a series of interbedded quartzites and dolomites. The following section of the Pogonip Group was measured in Trail Canyon (fig. 24). Bection of Pogonip Group, south side of Trail Canyon [Measured by Charles B. Hunt, R. J. Ross, Jr., and A. R. Palmer] Feet Top. Base of Eureka Quartzite; contact gradational. Contact taken at base of first quartzite; above this is 120 ft of interbedded thin-bedded quartzite and sandy dolomite transitional to overlying massive quartzite. 1. Upper dolomite unit: mostly thick-bedded dolomite; bottom 75 ft is thin bedded, but the dolomite above this is massive with a few thin lenses of friable sandstone ; abundant "Girvanell¢"; top 100 ft thinner bedded; several intraformational conglomerates; abundant Palliseria. Colln. F-8, F-13, F-27, and F-28 from this unit 3885 2. Middle shaly unit; interbedded shale, siltstone, and dolomite ; the clastics weather red and brown, probably because of metamorphism. Black limestone, 25-50 ft above base, with silt partings containing unidentifiable trilobites, brachiopods, and gastropods. Bed with cystid plates is 200-225 ft above base_________________ 285 8. Basal dolomite unit. Top 320 ft is thin-bedded dolo- mite interbedded with siltstone and shale; increasing shale upward gradational to unit 2. Lower 460 ft is thin-bedded dolomite, mostly weathering rustry brown; beds 2-4 in. thick; much black chert in lenses and in nodules elongated parallel to bedding; some blocky chert ; a striking bed of thin-bedded blocky chert occurs 270 ft above the base. Intraformational conglomerate in beds 1-2 ft thick. Much of the dolomite is fine- grained calcarenite 780 Total thickness 1, 450 Base. 'Top of Nopah Formation; contact taken at base of the thin-bedded dolomites. Trace elements in four specimens from Ordovician units are given in table 13. The single sample of dolo- mite from the Pogonip Group is similar to those of the Ely Springs Dolomite and to those of the dolomite rather than the limestone of the Nopah Formation (table 12). EUREKA QUARTZITE The name Eureka Quartzite was first used in central Nevada (Hague, 1883, p. 262; 1892, p. 54-57; see also, Kirk, 1933), and the formation has been widely recog- nized in the Great Basin southward to the Death Valley region. It is a massive vitreous quartzite that serves as a valuable easily recognized marker bed in the midst A36 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA 13.-Trace elements in Ordovician units, Panamint Range [Semiquantitative spectrographic analyses by Uteana Oda and E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] Pogonip Eureka Element Group Quartzite | Ely Springs Dolomite Dolomite 15 <10 10 10 70 <10 30 50 8 2 2 50 <10 30 10 10 10 <10 <10 20 10 <10 <10 20 <1 x1 <1 «I1 20 200 20 20 <10 15 10 <10 <10 <10 <10 <10 <5 <5 <5 <20 5 <5 5 10 10 15 20 20 150 <20 200 200 _>5 0. 05 _>5 >5 NotE.-Also found: Sn, <10; Ag, <1; Ge, <20; As, <1,000; Sb, <200; In, <50; Cd, <50; Tl, <100; Ta, <50; W, <50; Nb, <10. of the thick section of carbonate formations (figs. 24, 27). In Tucki Mountain the Eureka Quartzite is very much crushed and granulated, so that sections there cannot be regarded as meaningful for stratigraphic study. In this respect the Eureka Quartzite in that part of the area resembles the Stirling and Zabriskie Quartzites. In Trail Canyon, however, the formation seems to be less deformed. The quartzite there is not severely granulated (fig. 252), and on the ridge south of Trail Canyon a measured section, which follows, in- dicates that the formation there is 350 feet thick. Rection of Eureka Quartzite, ridge south of the mouth of Troil Canyon [Measured by Charles B. Hunt, R. J. Ross, Jr., and A. R. Palmer] Top. Base of Ely Springs Dolomite; contact concealed by rubble. Feet 1. Quartzite, well-bedded in beds 2-5 ft thick___________ 60 2. Quartzite, massive; weathers brown 110 3. Quartzite, mostly thin-bedded but with 2 ledges each about 15 ft thick ; thin beds between the ledges fucoidal and mottled red 60 4. Quartzite and sandy dolomite, interbedded ; gradational downward to dolomite unit at top of Pogonip Group ; colors variegated N 120 Total thickness Eureka Quartzite______________ 350 Base. Top of Pogonip Group; Contact taken at base of lowest bed of vitreous quartzite. Another section was measured across the crushed quartzite in Little Bridge Canyon (fig. 27). There the contact with the Ely Springs Dolomite is sharp but seems to have been sheared. The massive vitreous quartzite is 140 feet thick, and under this unit is 35 feet of thin-bedded very fine grained quartzite with a few thin beds of dolomite. The beds are 6 inches to 1 foot thick, the colors are variegated ; the weathered surfaces are mottled red and green. The quartzite at this location undoubtedly is thinned by shearing. In the northern part of the Panamint Range the Eureka Quartzite attains a thickness of 400 feet (McAllister, 1952, p. 12), in the Beatty area it is 350 feet thick (H. R. Cornwall, written commun., 1960), and in the Funeral Mountains it is about 360 feet thick (C. A. Richards ?). In the Nopah Range the thickness is 265 feet (Hazzard, 1937b, p. 276), and at the Nevada Proving Grounds it is 285 feet (Johnson and Hibbard, 1957, p. 349-350). No fossils have been found in the Eureka Quartzite in this area, but the age is restricted to Middle or early Late(?) Ordovician by the fossils in the underlying Pogonip Group and overlying Ely Springs Dolomite. A single specimen of Eureka Quartzite, analyzed for trace elements (table 13), contains even less trace elements than does the Zabriskie Quartzite (table 9), which it most resembles. ELY SPRINGS DOLOMITE The name Ely Springs Dolomite was first applied to a formation of dark dolomite about 600 feet thick in the Ely Springs Range about 125 miles northeast of Death Valley (Westgate and Knopf, 1932, p. 15). The formation has since been widely recognized in the southern Great Basin. Its thickness ranges from 400 to 940 feet: in the Nopah Range, 800 feet (Hazzard, 1937b, p. 276) ; in the Beatty area, 400 feet (H. R. Cornwall, written commun., 1960); in the northern Panamint Range 940 feet (McAllister, 1952) ; and in the Darwin area 920 feet (Hall and MacKevett, 1958, p. 7). At most of these places and in the Death Valley area, the Ely Springs Dolomite contains Late Ordo- vician fossils; it overlies the Eureka Quartzite and is overlain by dolomite containing Middle Silurian fossils. In the Death Valley area the thickness of beds as- signed to the Ely Springs Dolomite is substantially less than in the surrounding region. In Trail Canyon the thickness is 425 feet; in the Funeral Mountains 403 feet of beds was assigned to the formation (C. A. Richards ®). The formation is comparably thin at the north base of Tucki Mountain. At the widest place in the outcrop belt of the formation, at the south side 2 See footnote, p. A35. 8 See footnote, p. A85. " STRATIGRAPHY AND STRUCTURE ABT 27.-View of Eureka Quartzite (Oe) and overlying Ely Springs Dolomite (Oes) at mouth of Little Bridge Canyon. The quarzite is much more crushed and granulated than is the dolomite and as a result has been eroded to form the valley in the foreground; carbonate formations form the ridges on either side. of Tucki Mountain overlooking Tucki Wash, the com- puted thickness is 825 feet. More detailed work will be required to determine whether the differences in thickness are due to stratigraphic changes or to cutting out of beds by shearing along the bedding. Only a small part of the differences in thickness can be at- tributed to differences in boundaries selected for the formation. The basal contact with the Eureka Quart- zite, though generally covered, can be located within a few feet (fig. 27). The boundary with the overlying light-colored dolomites, some of which contain Silurian fossils, is gradational through a zone of perhaps 100 feet. The Ely Springs Dolomite in the Death Valley area is dark, thick bedded, and forms conspicuous cliffs above the light-colored Eureka Quartzite. The formation contains considerable dark-brown to black chert that occurs as nodules and as irregular lenses. The dark dolomite is streaked with curving light-colored lines 2-5 cm long and 1-5 mm wide, suggestive of scattered strands of spaghetti. Figure 25C is a micrograph of Ely Springs Dolomite. A38 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA The Ely Springs Dolomite has yielded a considerable fauna indicative of Late Ordovician (Richmond) age. Seven collections were made, as follows : F-8 (D};38-CO). Ely Springs Dolomite, 10 ft above base of the formation, in Little Bridge Canyon, Stovepipe Wells quad. sec. 15, T. 16 S., R. 45 E.). Identifications by R. J. Ross, Jr., "Lepidocyclus cf L. laddi Wang; Austinella sp.; strophomenid brachiopod ; dalmanellid brachiopod ; un- identified coral. 'The age is probably Late Ordovician, but it might be late Middle Ordovician." F-12 (D64;-CO). Lower part of Ely Springs Dolomite, south side of Trail Canyon, alt 1,340 ft at north base of butte with peak at 1,680 ft. F-17 (D151-SD). Middle of the formation ; 1 mile east of the mouth of Trellis Canyon, alt 1,200 ft, north foot of Tucki Mtn., Stovepipe Wells quad. (NBZ NE! sec. 26, T. 16 S., R. 45 E.). Collections F-12 and F-17-58 were examined by W. A. Oliver, Jr., who states "they consist, respectively, of ' and 6 fragments of small simple horn corals, mostly streptelasmatoids. These are very poorly preserved and cannot be identified. They could be of either Ordovi- cian or Silurian age but not pre-Middle Ordovician." F-} (not catalogued). 1% miles north of Trail Canyon, fault block at east end of the ridge dividing the valley; alt 1,800 ft. This collection, examined by E. L. Yochelson, yielded only isolated crinoidal columns. F-45 (8622-CO). Upper part of Ely Springs Dolomite, north side of canyon next north of Trail Canyon and 2% miles west of SW cor. see. 30, T. 18 S., R. 47 E., Furnace Creek quadrangle. Identifications by W. A. Oliver, Jr., "Tolline [manipora] sp.; streptelasmatical horn corals. The genus Tollinae is known only from rocks of Late Ordovician age. One of the two specimens is very well preserved and is specifically distinct from representatives of the genera that I have previously seen or seen illustrated. The genus is known from the Montoya Dolomite in Texas and the Red River Formation of Manitoba as well as from the U.S.S.R. Streptelasmatid horn corals of this type range from the Middle Ordovician to the Silurian and Devonian." F-49 (3623-CO). Corals from black dolomite believed to be Ely Springs near the middle of the formations; Captured Canyon at hill 800 ft in altitude near the mouth of the canyon ; 2% miles west of SW cor. see. 18, T. 25 N., R. 1 E., Furnace Creek quad. Identification by W. A. Oliver, Jr., "Atrepte- lasma? sp., one specimen; streptelasmatid horn corals, three specimens. This collection may well be Upper Ordovician since streptelasmatids are common in rocks of this age. They are not diagnostic, however, and the age will have to be based on other criteria." F-74 (8624-00). Middle of Ely Springs Dolomite, % mile south of Trail Canyon; saddle 500 ft west of hill 1932. Iden- tification by W. A. Oliver, Jr., "Bighornie sp., two specimens ; Grewingki@ sp., one specimen ; angulate streptelasmatid, one specimen; other streptelasma- toids, four specimens; small branching bryozoans. This assemblage is certainly Upper Ordovician as the genera Bighornia and Grewingkic are so limited. These corals are characteristic of the Ely Springs, Bighorn, and Red River Formations in western North America." At F-75, an isolated hill at the mouth of Trellis Canyon (SE-NE-sec. 23, T. 16 S., R. 45 E.) dolomite thought to be Ely Springs, or possibly Silurian, con- tains biconvex cross sections. Receptaculites has been reported from Ely Springs Dolomite at the east foot of the Panamint Range along Trail Canyon (Hopper, 1947, p. 407). The Ely Springs Dolomite was correctly identified by Hopper; but if the Receptaculites came from that formation, it is the only recorded occurrence of the genus in the formation in this entire region. Perhaps the fossil came from a fault block of dolomite belonging to the upper part of the Pogonip Group, which contains abundant Re- ceptaculites. The Ely Springs Dolomite is considered to be Late Ordovician in age. Trace elements in two samples of the Ely Springs Dolomite are given in table 13. The amounts and pro- portions are about the same as in dolomite from the Pogonip Group. SILURIAN AND DEVONIAN SYSTEMS-HIDDEN VALLEY DOLOMITE The Hidden Valley Dolomite, named for exposures in the northern Panamint Range (McAllister, 1952, p. 15) where it is 1,365 feet thick, is a light-colored for- mation that contrasts strikingly with the dark under- lying Ely Springs Dolomite (fig. 28). Throughout the region the Hidden Valley Dolomite is conformable on the Ely Springs Dolomite. At the type locality the , upper contact is conformable (McAllister, 1952, p. 15), but in some areas the top of these beds is an unconform- ity (Hazzard, 19376, p. 327). In the Panamint Range, south from Tucki Mountain, the Hidden Valley Dolomite is of variable thickness. It has a computed thickness of 750 feet at the north base of Tucki Mountain between Little Bridge Canyon and Trellis Canyon. It has a computed thickness of slightly less than 600 feet at the south side of Tucki Mountain. In the ridge south of Trail Canyon it has a measured thickness of only 300 feet. In the Funeral Mountains east of Death Valley a thickness of 1,473 feet is indicated (C. A. Richards *). I have not deter- mined whether these differences in thickness are due to stratigraphic changes or to crushing and shingling of the beds because of the intense structural de- formation. In this area the formation is light colored, thick bedded (fig. 28), fine grained, and even grained. Many beds contain crinoid stems; fragments of some large * See footnote, p. A35. ra STRATIGRAPHY AND STRUCTURE A39 Ficurs 28.-View of Ordovician, Silurian, and Devonian formati overlain by Pogonip Group (Op). Eureka Quartzite (Oe) forms the ligh slope above the Ely Springs Dolomite is Hidden Valley Dolomite (DSh) ; the striped slope is Photograph courtesy of John H. Maxson. ones are as much as half an inch in diameter. The top of the formation is taken at the base of the first quartzite beds that characterize the lower part of the Lost Burro Formation in this area. No fossils, except crinoid stems, were found in the Hidden Valley Dolomite, but search was restricted to the Trail Canyon area and the north base of Tucki Mountain. ons on the south side of Tucki Mountain. At left is Nopah Formation (Cn) t band under the dark Ely Springs Dolomite (Oes). The gray formed by the Lost Burro Formation (Di). At the type locality and other nearby places in the northern Panamint Range, fossils in the lower part of the formation include (McAllister, 1952, p. 16-17) : Halysites catenularia (Lin- Porpites porpite (Linnae- naeus) us) microporus (Whitfield) Favosites cf. F. nagarensis Hall A40 Fragments of bryozoa and a few brachiopods of Silurian nities. Fossils from beds 15-65 feet below the top of the formation in the northern Panamint Range, indicating an Early Devonian age, include (McAllister, 195%, p.: 17): Favosites sp. Papiliophyllum elegantulus Branching Cladopore Heliolites sp. (Stumm) Acrospirifer k o b e h an a Breviphyllum - lonen sis (Merriam) (Stumm) M eristella robertsensis Unidentifiable cup corals Merriam Platyceras sp. In the Funeral Mountains, on the east side of Death Valley, the lower 200 feet of the formation yielded (C. A. Richards ®) : Ayringopora sp. Plectatrypa sp. Heliolites sp. Favosites sp. Rugose corals Richards also reports the following from beds 200- 550 feet above the base of the Hidden Valley Dolomite : Meristella? sp. Eospirifer sp. Crinoid stems Rhynchonella sp. Cladopora sp. Stromatopora sp. Halysites sp. sp. Plectatrypa sp. Pentameroid brachiopod, Heliolites sp. Virgiana? sp. Favosites sp. Brachiopod fragments Rhynchonella sp. Gastropods Rugose corals Crinoid stems Cladopore sp. Stromatopore sp. Cornulites sp. on Syntro- phina? sp. From a 10-foot fossiliferous dolomite about 200 feet below the top of the Hidden Valley Dolomite, Richards obtained : Heliolites sp. Zaphrentid-type corals Halysites of H. labyrinthica (Goldfuss) Favosites sp. _ The fossils obtained from the formation in areas near Death Valley indicate a Silurian and Early Devonian age. f No samples of the Hidden Valley Dolomite were col- lected for trace-element analysis. DEVONIAN SYSTEM-LOST BURRO FORMATION The Lost Burro Formation at the type locality in the northern Panamint Range is 1,525 feet thick and con- sists chiefly of light-gray dolomite striped with nearly black dolomite, and limestone with some thin quartzite beds (McAllister, 195%, p. 18). In the Darwin area the thickness of the formation is more than 1,700 feet and may be as much as 2,400 feet (Hall and MacKevett, ® See footnote, p. A835. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA Dusty (containing organic matter?), microcrystalline ~ limestone Shell fragment Clear granular /- limestone FrcurE 29.-Micrograph of thin section of limestone from Lost Burro Formation. The limestone is mottled with dusty micro- crystalline limestone masses separated by more coarsely crystal- line clear limestone. Many of the microcrystalline masses have structures suggesting an organic origin. Diameter of field, 2.5 mm. 1958, p. 8). Only the lower 750 feet is present in the Funeral Mountains, the upper part having eroded (C. A. Richards ®). In the Nopah Range beds of Devonian age, referred to as the Sultan Limestone, are 1,720 feet thick (Hazzard, 1951, p. 1503). In the Death Valley area, on Tucki Mountain, the formation has the striped appearance (fig. 28) so char- acteristic of the type locality. The formation is mostly limestone (fig. 29) with only minor amounts of dolo- mite and thin beds of sandstone and quartzite. Many of the dark beds are mottled by whitish bodies resem- bling chopped spaghetti. _ An attempt was made to measure a section of the Lost Burro Formation along the north foot of Tucki Moun- tain eastward from the mouth of Trellis Canyon, but the attempt was only partly successful because of faults. The indicated thickness is about 2,000 feet. The base, which seems to be of Middle Devonian age, was taken just below a pair of quartzite beds, each about 3 feet thick and separated by 20 feet of carbonate rocks. These quartzites are overlain by 800 feet of alternating light and dark limestone in beds 1-10 feet thick, the striped beds. Above this striped unit is 200 feet of lime- stone and dolomite with numerous thin beds of sand- stone or quartzite The quartzite, mostly medium grained, occurs in pods and in beds 2 inches to 3 feet thick. Fossil collection F-16 is from the top of this unit. Above this unit are massive dolomitic beds, but the section appears to be duplicated by faulting. The ® See footnote, p. A35. STRATIGRAPHY AND STRUCTURE upper 200 feet of the formation consists of well-bedded and even-bedded limestone and quartzite in beds 5 and 6 feet thick. An unknown thickness of beds, but prob- ably not over 500 feet, lies below this unit and the bed represented by fossil collection F-16. The top of the Lost Burro Formation is taken at a quartzite imme- diately underlying limestone of Mississippian age represented by collection F-93 (p. A44). The top of the Lost Burro Formation seems to be of early Late Devonian age. Fossils from the base of the Lost Burro Formation were obtained at two locations. F-18. Base of Lost Burro Formation, light-colored dolomite overlying the lowest quartzite on ridgetop (alt 1,600 ft) 1 mile east of Trellis Canyon, Stovepile Wells quad. (NENE! sec. 26, T. 16 S., R. 45 E.). Report by Jean M. Berdan, "This collection contains brachiopods referable to Emanuelle and small specimens of Atrypa. Although the genus Atrypa has a long range, occurring from the Silurian through the early Upper Devonian, according to Cooper (in Shimer and Shrock, 1944, p. 329) Emanuelle is indicative of Middle or Upper Devonian. 'This collection, therefore, is probably Middle or early Late Devonian in age." F-46. Base of Lost Burro Formation on south slope of ridge 2% miles north of Trail Canyon and 2% miles west of SW cor. sec. 30, T. 18 S., R. 47 E., Furnace Creek quad. Report by C. W. Merriam, "cyathophyllid rugose coral, deep calyx; Stringocephalus sp. cf. 8. burtini Defrance; indeterminate gastropods, at least two genera. One large individual of Atringocephalus is fairly well preserved, showing the characteristic rodlike cardinal process of the dorsal valve. The rock contains abundant fragmentary silicified shell fragments of Atringo- cephalus and other smooth-shelled brachiopods, some of which could be the terebratuloid Rensselandia. These shells come out with acid but are not complete enough for positive identification. This collection represents the late Middle Devonian 'Stringocephalus' zone now recognized widely in the Great Basin." Other collections of fossils, obtained from the middle or upper part of the Lost Burro Formation, include: F-). Probably near middle of the Lost Burro Formation. Limestone butte below the mouth of Trellis Canyon. Stove- pipe Wells quad. (SW% sec. 13, T. 16 S., R. 45 E.). Report by C. W. Merriam, "stromatoporoids; Atrypae cf. A. mis- souriensis fine-ribbed form, abundant; Tabulophyllum sp. early Late Devonian." F-6. Near middle of Lost Burro Formation; 4 mile northeast of mouth of Little Bridge Canyon, Stovepipe Wells quad. (north side SEY% sec. 10, T. 16 S., R. 45 E.). Report by C. W. Merriam, '"stromatoporoids; Amphipora sp., Atrypa sp. Age: late Middle or early Late Devonian." F-7?. Near F-6. Report by C. W. Merriam, "stromatoporoids; abundant small indeterminate pelecypods resembling the genus Edmondia; Spirifer cf. 8. utahensis Meek; abundant small indeterminate rugose corals with deep calyx. Age: Early Late Devonian." F-16. Lost Burro Formation, about 1,000 ft above the base; 1% miles east of mouth of Trellis Canyon, Stovepipe Wells 776-623 O-66-4 A41 quad. (SEZ%NW% sec. 24, T. 16 S., R. 45 E.). Report by C. W. Merriam, "stromatoporoids; Syringopore sp.; ?0re- copia mecoyi (Walcott) : indeterminate rugose coral,. Age: Early Late Devonian." Merriam goes on to report, "Rocks represented by coll. F-4, 6, 7, and 16 are seemingly correlative with middle and upper parts of the Devils Gate Limestone of central Nevada." F-65. Brachiopods and corals from near the top of the Lost Burro Formation; overlies red limy shale and siltstone. In butte isolated from Tucki Mtn., NE sec. 14, T. 16 S., R. 45 E. Mackenzie Gordon has reported as follows: "Horn corals, genus and species indet. Stromatoporoid cf. Stachyodes or Idiostroma sp. indet. Cyrtospirifer or Cyrtiopsis sp." «W. A. Oliver, Jr., says that the corals are simple types that are known to range through Silurian and Devonian rocks but not diagnostic of any one particu- lar zone. Helen Duncan says that the corals are not Carboniferous types and that the small stromatoporoid is of a type characteristic of Devonian rocks. Jean Berdan confirms my belief that the silicified brachio- pods are Late Devonian types and belong in one of the two mentioned genera, though they are not complete enough to be sure which." F-90. _ North base, Tucki Mountain. Stromatoporoid reef about 750 ft above the base of the Lost Burro. Stromatoporoid- and AmpAipora(?)-bearing beds are particularly abundant near the middle of the Lost Burro Formation (fig. 30). Beds containing numer- ous brachiopods, including the diagnostic Cyrto- spirifer (fig. 31), mark the top of the Lost Burro For- mation. Syringoporoid corals are present in both Devonian and Mississippian limestones. The Devonian forms can be distinguished from the Mississippian forms on gross morphology (fig. 32) and can be useful field guides for distinguishing formations of these ages. At the type locality in the northern Panamint Range the uppermost 35 feet of the Lost Burro Formation contains the following Late Devonian fossils (McAllis- ter, 1952, p. 19) : Cyrtospirifer cf. C. monticola (Haynes) disjunctus (Sowerby) Tylothyris? cf. T.? raoymondi Haynes "Camarotoechia" aff. "C." duplicata (Hall) Cleiothyridina cf. C. devonica Raymond Productella sp. The Lost Burro Formation as mapped in this area is considered to be Middle and Late Devonian in age. Trace elements in some samples from Devonian and younger formations are given in table 14. Most of the formations are represented by only a single sample. The samples suggest that the younger rocks have the greater concentrations of elements. A42 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA FIGURE 30.-Stromatoporoid (upper) and Amphipora(?) (lower) beds are abundant in the middle of the Lost Burro Formation. FIGURE 31.-Limestone containing Cyrtospirifer, which is diagnostic of the uppermost Devonian. A somewhat similar appearing spirifer is present in the lower part of the Tin Mountain Limestone. TABLE 14.-Trace elements in Devonian and younger Paleozoic formations [Semiquantitative spectographic analyses by Uteana Oda and E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] Lost Rest Spring | Pennsylvanian and Permian Burro | Tin | Limestone Shale formations on Tucki Mountain Ele- For- | Moun-) from upper ment ma- | tain | part of the tion |Lime-| Mississip- | Lime- Altered rock at Lime-| stone pian stone | Shale | Limestone thrust fault stone <10 10 <10 | <10 10 | <10 | 500 |>10,000 |>10, 000 50 100 30 100 | 7,000 20 15 50 T +4 <5 50 10 10 5 >500 100 <10 <10 <10 20 150 10 10 30 20 <5 <5 <5 10 100 <5 10 <5 <10 <10 <10 <10 30 <10 | <10 <10 <10 20 20 10 20 70 0 10 10 <10 <10 10 10 15 100 10 | <10 10 <10 <1 7 0. 5 io sh paua mols dest: Clent diel At the north end of the Black Mountains the forma- tions in the Artists Drive area are overlain unconform- ably by the Furnace Creek Formation of Pliocene age. The age of the greater part of the formations in the Artists Drive area and to the north is in doubt, but the uppermost tongue of playa beds in the Artist Drive Formation has yielded diatoms indicating an early Plio- cene age. The fossils were obtained by K. E. Lohman (written commun., 1961), of the U.S. Geological Sur- vey, who has reported as follows: Loc. 8967. Hard thin limestone from center of WVNE%4 sec. 7, T. 26 N., R. 2 E., Furnace Creek 15-minute quad. Assigned to early Pliocene on basis of incomplete, partly altered diatom assemblage. The formations in the Artists Drive area also are represented in several large downfaulted blocks in a belt 10 miles long and 2 miles wide at the foot of the Black Mountains north of the Badwater turtleback. The exposed beds, like those in the Black Mountains, are volcanic towards the south, and interbedded vol- canic and sedimentary rocks at the north. They are A54 from the upper part of the formations, and the displace- ment must be about 5,000 feet down towards Death Valley. If the Tertiary formations were as resistant to erosion as the Precambrian gneiss, this part of the front of the Black Mountains would also be a turtleback surface. These downfaulted blocks in the Artists Drive area are overlapped unconformably by the Pliocene and early Pleistocene(?) Funeral Formation and basalts interbedded with it. FORMATIONS AROUND COTTONBALL BASIN Tertiary formations around Cottonball Basin at the north end of the Death Valley saltpan range probably from Oligocene to Pliocene. They occur in fault blocks protruding through and largely concealed by the Qua- ternary fan gravels. No fossils were found, and the outcrops are too isolated for satisfactory reconstruction of a stratigraphic succession. The stratigraphy of these deposits is uncertain ; the structural geology neces- sarily even more so. The deposits are in three principal belts (fig. 40). At the north, between the Kit Fox Hills and the Funeral Mountains and extending southeast in a narrow belt along the fault at the foot of the Funeral Mountains, are clastic deposits believed to correlate with the Titus Canyon Formation of Stock and Bode (1935) and ac- cordingly thought to be Oligocene. Deposits believed to be somewhat younger, perhaps Miocene, form an in- termediate belt at the Kit Fox Hills and southeastward along the northeast side of Cottonball Basin. The third belt extends northwest and southeast from Cottonball Basin and is represented by the Furnace Creek Forma- tion of Pliocene age. OLIGOCENE(?) FORMATIONS Shale, sandstone, grit, and conglomerate thought to correlate with the Titus Canyon Formation of Stock and Bode (1935) from isolated hills protruding through the Quaternary fan gravels between the Kit Fox Hills and Funeral Mountains. These beds also occur in a narrow belt along the fault at the foot of the Funeral Mountains and on a turtleback fault surface on Pale- ozoic formations in the southern part of the Funeral Mountains. Most of the formation is dark red or dark brown ; many clayey beds are light green. The bedding is highly lenticular. The total thickness of the Titus Canyon(?) Formation in these areas can only be guessed, because the outcrops are not continuous and the formation is very much faulted. At least 1,500 feet of beds is exposed, and the total thickness may greatly exceed this. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA Of the several kinds of lithologies that are included in the formation, three are distinctive: conglomerates in which the cobbles are fractured; green clayey and silty beds that contrast strikingly with the enclosing thicker and more coarsely clastic beds; and a bright-red conglomerate along the faults at the foot of the Funeral Mountains. The conglomerate having fractured cobbles occurs in beds 10-25 feet thick at many horizons through the middle 1,000 feet of the formation. Cobbles are as much as 6 inches in diameter and are displaced as much as one-fourth inch by fractures oriented normal to the bedding. Many of the fractures are healed, and the fractured cobbles can be removed intact. The fractured cobbles may touch one another, or they may be isolated in a matrix of gritty silt (fig. 41). The distinctive greenish clayey beds, mostly less than 10 fet thick, are tuffaceous (fig. 42). They are con- spicuous because most of the formation is dark red or dark brown. The red conglomerate and sandstone is at least 500 feet thick and occurs along the faults at the foot of the Funeral Mountains. The conglomerate contains well- rounded cobbles and pebbles of quartzite along with the more angular boulders of limestone and dolomite. It is faulted against the Cambrian and Precambrian formations that form the foot of the mountain. The reddening may be due to hydrothermal alteration along the fault zone. The following is a typical but partial section of the Titus Canyon (?) Formation : Partial section, Titus Canyon(?) Formation, measured about midway between the Kit Fox Hills and Funeral Mountains Top covered. About 750 ft of beds like units 1 and 2 up to top of this member. Feet 1. Sandstone, gritty, with scattered cobbles ; some cobbles as much as 3 in. in diameter ; weathers dark brown- - 200 2. Interbedded tan siltstone and dark-brown grit and cobble conglomerate. Cobbles as much as 3 in. in diameter: fractured. Some 30 3. Sandstone, gritty, with scattered cobbles ; some cobbles as much as 3 in. in diameter ; weathers dark brown__ 60 4) Tan beds like unit 2 ct _ _to nl 60 on . Grit, sandstone, and conglomerate with pebbles as much as 2 in. in diameter of quartz, quartzite, carbonate rocks, black chert ; no pebbles of volcanic rocks ; dark brown. Possible tuff layers. Thin beds; apparently some interbeds of greenish shale__________________ 110 6. Greenish shale in beds 5-10 ft thick with 1- to 6-in. beds of tan limestone and silt and a bed of reddish cemented clay or gilt. 3. "_L c_ 50 7. Like unit 5; weathers dark brown but is gray on fresh fracture. Across wash to southeast the top of this units is cut off discordantly by unit 6; this may be a flat fault and not an unconformity______________ 40 % ener th nn \\ $2: ¢... STRATIGRAPHY AND STRUCTURE EXPLANATION 2222022 —-—U ---------------- D Contact Normal fault Dashed where approximately lo- Dotted where concealed; U, up- cated; dotted where concealed thrown side; D, downthrown side -A__A AA .. A .. A .. A. Thrust fault Tick marks on side of upper plate t> Dip and strike of beds Pms Generalized outline of mountain ranges NZ {f" ZnS a's. Q t _ -C: AT o al -O o 10 MILES A55 Q Quaternary deposits Furnace Creek Formation Miocene(?) deposits Titus Canyon(?) Formation of Stock and Bode (1935) Paleozoic formations Tm p€ 3 LL Precambrian formations FIGURE 40.-Sketch map of Tertiary formations around Cottonball Basin. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA FicurRB 41.-View of fractured cobble conglomerate in the Titus Canyon(?) Formation of Stock and Bode (1935). through the cobbles and some cross from one cobble to another. parallels the elongation of the cobbles. Partial section, Titus Canyon(?) Formation, measured about midway between the Kit Fox Hills and Funeral Mountains- Continued Feet 8. Interbedded sandstone, grit, shale, and fine conglom- erate. Pebbles of Precambrian rocks as much as % in. in diameter, Gray unit with salt-and-pepper Appegralite - - ss _._. oul. ___ s. clo uue 25 9. Conglomerate, with fractured cobbles as large as 6 in. Brown sandstone above and below_________________ 15 Base concealed. The uppermost beds in the Titus Canyon (?) Forma- tion, estimated to be about 500 feet thick, are light colored and fine grained. The beds are mostly silt and The fractures extend They are oriented at right angles to the bedding, which approximately Displacements along the fractures are mostly less than a quarter of an inch. sand, in part limy, and very well bedded-even lam- inated. Dominant colors are yellow and light green. Other beds are platy limestone, mostly brownish, but some are light gray. All these beds are cut by veinlets of gypsum and anhydrite. Along the northeast side of the Kit Fox Hills the tex- ture of these beds ranges from clay to medium sand. The sandy beds are thickest, some are 8 inches thick; the clay stains blue when tested with benzidine, and ap- parently is a montmorillonite. Colors are mostly pastel shades of lavender, brown, and red. Overlying these beds are red and buff sandy beds at the base of the buff conglomerate forming the Kit Fox Hills and mapped as Miocene( ?). STRATIGRAPHY 42.-Micrograph of thin section of greenish clay from the Titus Canyon(?) Formation of Stock and Bode (1935). Diameter of field, 2.5 mm. Well-rounded microcrystalline grains, probably chalcedony (C) have eryptocrystalline (or pos- sibly argillized glass?) rims. Rounded quartz grains (Q) and some feldspar (F) occur in the groundmass ; some, like the example in the north- east quadrant, are surrounded by microcrystalline material that is surrounded by an irregular discon- tinuous rim of highly birefrigent material, prob- ably a clay mineral (black areas). Scattered through the rock are isotropic shards (S) ; many of these now are holes through the slide as if their glass had been removed by solution. Some rounded grains (not shown) are greenish and might be pollen, but more likely they are stained rims on grains of chalcedony. In brief, the lowest part of the Titus Canyon (?) For- mation appears to be fanglomerate. The middle part contains conglomerate interbedded with fine-grained beds. The upper part seems to be largely a playa deposit. Some analyses of trace elements in beds of the Titus Canyon (?) Formation are given in table 16. The tuff is similar to the volcanics in the Artists Drive Forma- tion (table 15). As noted by Noble and Wright (1954, p. 149), these beds are similar to the Titus Canyon Formation which, in the Grapevine Mountains north of this area, has yielded Oligocene vertebrate fossils (Stock and Bode, 1935). The beds probably also correlate with the lower part of the formations in the Artists Drive area (Noble and Wright, 1954, p. 149) in the northern part of the Black Mountains. The faults along the foot of the Funeral Mountains north of Echo Mountain dip 25°%-30° towards Death Valley. The Titus Canyon(?) Formation was de- posited against the fault surface and subsequently faulted down against it. MIOCENE(?) FORMATIONS Tertiary deposits in the Kit Fox Hills and in the fault blocks southeastward to the foot of the Funeral 776-623 O-66-5 AND STRUCTURE A57 TaBur 16.-Trace elements in beds correlated with the Titus Canyon (?) Formation of Stock and Bode (1985) [Semiquantitative spectrographic analyses, by E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] Gritty Element Greenish beds Tufl sandstone, brown 50 70 10 20 150 500 200 700 70 100 5 100 500 300 300 100 <5 50 5 10 «10 10 <10 10 30 200 10 100 100 50 20 20 1 1 <1 3, 000 7, 000 2, 000 3, 000 200 700 200 100 50 50 50 <50 <10 20 <10 <10 20 150 10 70 700 700 500 2, 000 300 300 70 1, 000 1 5 0. 3 5 Note-All samples showed: As <1,000; Sn <10; Ge <20; Ga <20; Cd <50; In <50; Sb <200; Tl <100; Ta <50; W <50; Ag <1. Mountains constitute an intermediate belt between the outcrops of the Titus Canyon (?) Formation of Stock and Bode (1935) and those of the Furnace Creek For- mation (fig. 40). The deposits, estimated to aggregate about 4,000 feet thick, are thought to overlie the Titus Canyon(?) Formation and to underlie the Furnace Creek Formation, but because of the faulting, this se- quential relationship has not been established, and the stratigraphic position is assumed. The color of these deposits tends towards buff and light red ; it is suggestive of coarse facies of the Muddy Creek Formation-which is considered to be of Plio- cene(?) age and which is extensive east of Death Val- ley. The Titus Canyon (?) Formation tends to be much darker, and the Furnace Creek Formation tends to be much lighter. In the Kit Fox Hills the deposits are mostly reddish conglomerate containing quartzite and chert cobbles. Limestons, dolomite, and volcanic cobbles make up a minor part. A pebble count near the north side of the hills showed the following percentages: Red and pur- ple quartzite and chert, 40; sandstone, 40; shale, 10; schist, 5; other, 5. This suggests a source in the north- ern part of the Funeral Mountains. Along the south side of the Kit Fox Hills the felsite cobbles increase to about 15 percent, and limestone and dolomite to about 10 percent. Southeastward along the Kit Fox Hills the volcanic rocks in the cobbles increase to 35 percent; at one place a count showed 60 percent volcanic rocks. The other materials are chiefly quartz- ite and chert rather than carbonate rocks. A58 Northwestward the lower part of the conglomerate grades into fine-grained sedimentary deposits, and this, too, suggests a source to the northeast. Probably the conglomerate was thin, if ever present, northeastward across the belt of the Titus Canyon(?) Formation. Very possibly that area was a pediment that ended along a southward-facing fault searp at about the position of the present northeast-facing edge of the Kit Fox Hills; if so that area could have been bypassed by the Mio- cene( ?) deposits. Along the northeast side of Cottonball Basin are three bare hills of red conglomerate similar to that in the Kit Fox Hills. The conglomerate is about 1,400 feet thick at the southeasternmost hill, 1,000 feet thick at the mid- dle one, and about 900 feet thick at the northwest one. Three-quarters of the cobbles and pebbles are quartzite and chert; the remainder are volcanics and carbonate rocks. This conglomerate, like that in the Kit Fox Hills, probably was derived from the northern part of the Funeral Mountains. Fossiliferous limestone and dolomite from the Paleozoic formations, which com- pose a large fraction of the conglomerates in the Fur- nace Creek Formation, are notably lacking in these Miocene(?) deposits. This conglomerate is overlain by about 350 feet of white and gray tuffaceous beds containing thin reddish beds with pebbles, perhaps reworked from the conglom- erate and marking an unconformity. Overlying these beds and marking the top of the deposits mapped as Miocene(?) is a brown sandstone unit about 1,500 feet thick. The brown sandstone unit consists of brown limy grit, limy sand, friable sandstone, thin-bedded lime- stone, and a little greenish silt and shale. A few layers are pebbly. Limy beds are a few inches thick and are strikingly ripple marked. Sandy beds are 1-8 feet thick. Figure 437 is a micrograph of a thin section of a limy sandstone bed. Unidentifiable stem frag- ments of mongeotyledonous plants are common, and animal tracks have been reported in these brown beds (H. D. Curry, oral commun., 1960), but no identifiable fossils have been found. The light-colored tuffaceous beds and the brown sandy beds that overlie the conglomerates and that have been taken as the top of the deposits mapped as Miocene ( ?) are transitional between the Miocene(?) and Furnace Creek Formation. They could as well have been in- cluded with the Furnace Creek Formation. Underlying the conglomerate that forms the bare hills northeast of Cottonball Basin, and between those hills GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA and the Funeral Mountains, is a series of sandy and tuffaceous beds aggregating about 3,000 feet thick. A section northeastward from Cottonball Basin shows the following : FiGuRE 43.-Micrographs of thin sections of sedimentary rocks from Miocene(?) formations northeast of Cot- tonball Basin. Q, quartz ; F, feldspars; H, hornblende ; B, biotite; C, calcite; R, volcanic rock; atz, quartzite ; is, limestone or dolomite. Diameter of fields, 2.5 mm. A, Crystal tuff from lower part of the Miocene(?) beds. The matrix is calcite, fine glass fragments, and clay. Crystals are quartz, feldspars, biotite, and fragments of glassy volcanic rocks. ,B, Clayey tuff. Rectangular crystals are mostly feldspar, some mica. Shards of glass are angular. Matrix clay. C, Arkose from near the middle of the Miocene(?) formations. Differs from A in having greater variety of volcanic rock fragments, quartzite, limestone or dolomite, both argillized orthoclase and plagioclase feldspar; also has quartz and biotite. Matrix silty clay. D, Brown calcareous sandstone at top of the Miocene(?) forma- tions. Grains are quartz, argillized orthoclase, micro- cline, and plagioclase feldspar, hornblende, biotite, limestone or dolomite, quartzite, volcanic rocks of several kinds. Matrix is calcareous clay. STRATIGRAPHY AND STRUCTURE Bection northeastward from (firttonball Basin to the Funeral Mountains Feet Top. Red conglomerate forming bare hills at northeast edge of the basin 900-1, 400 1. White and light-gray tuffaceous sandstone, some grit, very little conglomerate; pebbles isolated from one another. Beds 1-2 ft thick and well laminated ___ 2. Brown limy sandstone, grit, conglomerate, and inter- bedded tuffaceous sandstone. Brown limy beds com- prise about half the unit; they are resistant and form the most conspicuous outcrops. Conglomerate beds are pebbly, with only a few cobbles. Pebbles are well rounded, partly polished; mostly various kinds of felsite and not many are of Precambrian or Paleozoic rocks 3. Buff and yellow arkosic sand and silt (fig. 43C), some thin beds of gray tuffa@eous sandstone. - Well bedded and finely laminated 4. Conglomerate, reddish; subround and subangular pebbles, cobbles, and boulders as much as 5 ft in dia- meter; boulders larger than not common ; most large boulders are a banded purple quartzite con- taining quartz veins as wide as %4 inch ; also present are cobbles of bull quartz. Source evidently was the Chloride Cliff district in the Funeral Mountains. Other materials include red and green banded quart- zite, sandy dolomite. Sorting poor; beds are 1-3 ft thick and contain all sizes of materials. Many boulders and cobbles are slabby ; their long axes par- allel the bedding. Estimated size proportions: 15 percent larger than 6 in.; 45 percent 1-6 in. ; 40 per- cent less than 1 in., including matrix______________ 1, 000 450 The conglomerate at the base of the section is a resist- ant unit that forms hills along the foot of the Funeral Mountains and in places lies against the frontal fault. Away from the fault the conglomerate seems to grade into and be intertongued with red sandstone that is in part tuffaceous (fig. 434, B). The tuffaceous layers are as much as 5 inches thick, and are separated by beds of fine-grained sandstone %-2 inches thick. The sand- stone contains shale laminae and is silty; it grades downward into light-colored beds thought to be the upper unit of the Titus Canyon (?) Formation. The composition of the tuffaceous rocks varies widely, depending on the proportion of volcanic debris to the clastics from the Precambrian. - In table 1/7 the contrast is illustrated by analyses of three random samples from this part of the section. In the Artists Drive area and in the Amargosa thrust complex the tuff differs in composition from the felsites, being notably higher in strontium and lower in tita- nium. Systematic chemical analyses of these volcanic rocks might help determine whether they are more closely related to those in the Amargosa thrust complex in the Black Mountains or to those in the rhyolite district northeast of the Funeral Mountains. A59 TaBuE 17.-Trace elements in the Miocene(?) deposits [Semiquantitative spectrographic analyses by E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg; which is given in percent] Tan limy Tuffa- sandstone Element ceous Tuff at top sandstone of for- mation PD meen e ice- 15 10 20 Mn. neuer reas 1, 000 50 1, 000 een atleast es 30 10 70 tee ien read 200 50 300 Niss: cele ne rece ca egen 20 <5 10 COz. :e T. <5 10 Vereen see afin aes a mdl ma a b 70 10 100 YC ae del n eee a oa ae alan 20 10 50 el <1 1 C TE Ef uss aol be gene. 5, 000 700 5, 000 Drac si auanas 100 70 100 Ha es 50 <50 50 Bolt ele lie ceed oue s 10 <10 10 Crd s. selle anata enn. 70 15 20 ci _ sc? 500 300 1, 500 Ecc! enacted on o 300 1, 000 700 Mg.. 1. 5 0. 5 3 NorE.-All samples showed: As<1,000; Zn<200; Sn<10; Ge<20; Ga<20; Cd<50; Bi<10; In<10; Sb<200; Tl<100; Nb<50; Ta<50; W<100. Despite uncertainties, the stratigraphy of these Mio- cene(?) deposits around Cottonball Basin does help in interpreting the structural history. The northwest- trending Furnace Creek fault zone is suspected to have had considerable lateral displacement (Noble and Wright, 1954, p. 153), but these Mioccene( ?) deposits are not offset laterally from their probable source in the Funeral Mountains. However, there may have been lateral displacement along faults farther to the south- west, PLIOCENE FORMATIONS Pliocene deposits are represented by the Furnace Creek Formation, which outcrops at the north end of the Black Mountains and northward from there to the fault along the southwest side of the Miocene(?) de- posits (fig. 40). The formation probably underlies Cottonball Basin, for it reappears northwest of there in the anticlinal uplift at the Salt Creek Hills. At the north end of the Black Mountains the forma- tion is more than 5,000 feet thick and consists in large part of fine-grained light-colored playa deposits (fig. 44). Interbedded with the playa deposits are con- glomerates and some basalts. The formation consists of a basal conglomerate of variable thickness, but averaging perhaps 200 feet, over- lain by 2,500 feet of light-colored fine-grained playa beds. Some of these beds are highly tuffaceous; others are clastic sand or silt (fig. 45). Interbedded with these are basalts and conglomerate beds. Some of the latter thicken westward toward the west front of the Black A60 Mountains. The playa beds are overlain by the con- glomerate seen at the right side of figure 44. This con- glomerate reaches a maximum thickness of about 2,000 feet at the mouth of Furnace Creek. It is overlain by another series of playa beds about 1,300 feet thick. Younger units of the formation, if any, are concealed under the Pliocene and Pleistocene(?) Funeral For- mation in the trough of the Texas Spring syncline (fig. 40). The basal conglomerate is composed mostly of cob- bles of Palezoic limestone and dolomite, and there are boulders as much as a foot in diameter. Among these cobbles are fossiliferous rocks from upper Paleozoic formations-fusulinid limestone from Pennsylvanian or Permian formations; granular limestone containing large crinoid fragments, almost certainly from the Tin Mountain Limestone or younger limestone; black do- lomite like that of the Tin Mountain; and limestone containing Cyrtospirifer from the Lost Burro Forma- tion. These fossiliferous cobbles may have been brought from the northwest, possibly from Tucki Mountain but more likely from farther north in the Panamint Range. About 65 percent of the cobbles are Paleozoic carbonate rocks; 10 percent are quartzite, 20 percent are volcanics, and a few percent are granite and miscellaneous other types. The granite does not look like the granites at GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA FicURE 44.-View of Furnace Creek Formation at north end of the Black Mountains. View is southwest and west from Zabriskie Point, an overlook by Highway 190 about 3 miles up Furnace Creek Wash from Furnace Creek Inn. The base of the Furnace Creek Forma- tion is at the topographic break between the badlands and the wougher and higher ground in the distance at the left. Light- Skidoo or at Hanaupah Canyon, and it is different in its trace elements. It contains a tenth as much lead and five times as much copper as do the Skidoo and Ha- naupah granites. Its content of zirconium is only a fifth as great, and it contains 10 times as much boron, 10 times as much strontium, 4 times as much vanadium and cobalt, and twice as much nickel as do the other granites. The percentage of volcanic rocks among the cobbles is low, considering that this basal conglomerate uncon- formably overlaps volcanic and other deposits of for- mations in the Artists Drive area. The proportion of voleanic rocks may increase southeastward, but such change was not determined. Whereas the basal conglomerate of the Furnace Creek Formation seems to have been derived in large part from the northwest, the conglomerate that outcrops at the mouth of Furnace Creek Wash and caps the lower playa beds member of the formation, seems to have been derived mostly from the Black and Funeral Mountains.: This conglomerate thins southeastward. At the mouth & STRATIGRAPHY AND STRUCTURE colored playa beds about 2,500 feet thick extend to the base of a con- glomerate which forms the dark cliff at the right. The beds are dip- ping to the right (north) into the Texas Spring syncline. Center of the picture looks west across Death Valley to the Panamint Range at Aguereberry Point; Tucki Mountain is at the right. Panorama by John Stacy. of Furnace Creek it is 1,800 feet thick. Two miles southeast from there it is 1,600 feet thick, and in an- other 2 miles it is only 1,000 feet thick. On the other hand, the proportion of volcanic rocks in the conglomerate increases southeastward as the con- glomerate thins, from 10 percent at the mouth of Fur- nace Creek to 20 percent where the formation is 1,600 feet thick and to 40 percent where the thickness is down to 1,000 feet. The proportion of quartzite and carbon- ate rocks changes irregularly. At the mouth of Fur- nace Creek there is 75 percent carbonate and 15 percent quartzite and other clastics; 2 miles southeastward the percentages are 30 and 45, respectively; and where the formation is 1,000 feet thick, the percentages are 50 and 10. These rocks look like early Paleozoic types and probably came from the southern part of the Funeral Mountains. Another conglomerate, perhaps 200 feet thick, is found along the west front of the Black Mountains in the playa beds about half way between the basalt con- glomerate and the one that crops out at the mouth of Furnace Creek. This conglomerate is composed very A61 largely of volcanic debris and thins southeastward, as if from a source at the site of Death Valley, or a source west of the valley, perhaps, in the Amargosa thrust complex. The contrast in sources of the different materials also shows well in some of the fine-grained playa beds(fig. 45). Some of these beds are largely of volcanic ma- terials; others are largely from Precambrian or Paleo- zoic formations. Probably there was a playa elongated northwestward at the present site of the north end of the Black Moun- tains, formerly the north base of a pile of felsitic volcanics (formations at Artists Drive) that had ac- cumulated on the Precambrian rocks farther south in the Black Mountains. Most of the fine-grained sedi- ments deposited in the playa were derived from the vol- canic pile to the south, but deposition was interrupted by influxes of coarse gravels from the northwest, pre- sumably in response to structural movements in that area,. During the second half of the time represented by the Furnace Creek Formation an increasing amount of sediment was brought from the south end of the Funeral Mountains. Lateral changes in thickness and geochemistry of the playa beds suggest that the central part of the Pliocene playa was a short distance east of the present edge of A62 FIGURE 45.-Micrographs of thin sections of playa de- posits in the Furnace Creek Formation. Q, quartz; F, feldspar ; B, biotite; M, magnetite ; G, volcanic glass ; atz, quartzite; is, dolomite or limestone; sh, shale or schist. Diameter of fields, 2.5 mm. 4, tuff layer, an ash fall. Angular shards of volcanic glass mixed with grains of quartz, biotite, feldspar, magnetite, and rounded grains of volcanic glass are in a matrix of sericite, quartz, and feldspar. ,B, poorly sorted sandy silt of clastic sediments, probably derived chiefly from the Funeral Mountains. The large grains are quartzite, both fine grained and coarse grained, dolo- mite or limestone, shale or schist, and scattered small grains of quartz and feldspar in a calcareous clay with minute grains of quartz. the saltpan in Cottonball Basin. Playa beds there are highly saline. At the East Coleman Hills, which are at the north tip of the outcrop area at the north end of the Black Mountains (fig. 40), the upper playa beds are at least 2,400 feet thick and contain sulfates and borates. About a mile southeast the upper playa beds are about 1,300 feet thick, and some contain abundant veins of gypsum. Farther to the southeast, along the flank of the Texas Spring syncline, these beds continue to thin to about 650 feet and contain less sulfate, al- most no chlorides, and more carbonate and granular tuff. The lower playa beds of the formation contain thick deposits of gypsum and of borates that were produc- tive during the days when the 20-mule teams operated. These deposits are southeast of those in the upper playa beds as if the sulfate-borate zone shifted northwestward towards Cottonball Basin. Today it is located at the edge of the saltpan. At the Salt Creek Hills, about 2,500 feet of light- colored playa beds of the Furnace Creek Formation are GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA TABLE 18.-Trace elements in the Furnace Creek Formation [Semiquantitative spectrographic analyses by E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] Element Tuff Basalt Element Tuff Basalt 70 20 I[ :::...... 500 |10, 000 500 | 1,000 || 100 | '100 50 70 || <50 | 100 $0 |-- ta0 | Se-..2.....z>. <10 20 10 {-> 200 20 | 300 <5 70 || 30 | 1, 500 0. |.: 150.1, 70 | 3,000 15 20 | 0. 2 5 g:: <1 NortE.-Both samples showed: As<1,000; Zn<200; Sn<10; Ge<20; Ga<20; Cd <50; Bi <10; In <10; Sb <200; Tl <100; Nb <50; Ta <50; W <100. exposed in an asymmetrical anticline. Westward along Salt Creek, basaltic (or andesitic) lavas and conglom- erate are inter bedded with the playa beds. The con- glomerate contains boulders of granite that may be part of a boulder train extending southeastward to the north end of the Black Mountains. Analyses of trace elements in a tuff and a basalt from the Furnace Creek Formation are given in table 18. The tuff has more lead, manganese, and copper, and less barium and strontium than does the tuff near the base of the Miocene(?) deposits (compare with table 17). The basalt differs from those in the Amargosa thrust complex (compare with table 26) in its higher content of nickel, boron, lanthanum, chromium, and strontium. Diatoms collected from the top and base of the Fur- nace Creek Formation indicate that it spans much of Pliocene time. The diatoms were collected by K. E. Lohman (written commun., 1961), of the U.S. Geolog- ical Survey. A collection near the base of the forma- tion is described as follows: Loc. 4159. Hard calcareous tufa immediately overlying in- trusive basalt, SW4NEY, sec. 27, T. 26 N., R. 2 E., Ryan 15- minute quad. Assigned to early Pliocene on basis of in- complete, partly altered diatom assemblage. The collection from near the top of the formation is described as follows (written commun., 1961) : Loc. 4070. 1.15 miles northwest of Travertine Point on High- way 190, roadcut in south side. Ryan 15-minute quad. Hard gray limestone containing an abundant and well-preserved diatom assemblage extraordinarily similar to a diatom assem- blage from a diatomite in Sand Pedro Valley, Ariz., which has yielded a vertebrate fauna of middle Pliocene age. Loc. 4070 has therefore been assigned to the middle Pliocene. Other plants from the Furnace Creek Formation, reported by Axelrod (1940), also indicate a Pliocene age for this formation. STRATIGRAPHY AND STRUCTURE PLIOCENE AND PLEISTOCENE(!) DEPOSITS-FUNERAL FORMATION The Funeral Formation crops out extensively in the © fault blocks that extend northwest from Furnace Creek along the east side of Cottonball Basin, in small areas in the Artists Drive fault blocks and near Mormon Point, and in an extensive area along Emigrant Wash and about as far as its head. In Furnace Creek Wash and around Cottonball Basin, fanglomerate of the Funeral Formation rests conformably on the light-colored playa deposits of the Furnace Creek Formation. - On the Artists Drive fault blocks the fanglomerate overlies volcanic and other rocks of the Artist Drive Formation with an angular unconformity. At Mormon Point the fanglomerate overlaps Precambrian rocks and is faulted against them. Along Emigrant Wash the fanglomerate overlies and is faulted against the turtleback surface on the west foot of Tucki Mountain (p. A143), and it overlies and is faulted against the west flank of the granite at Skidoo. In the absence of fossils, it is doubtful that these widely separated deposits are of the same age. On the basis of diatoms in the upper part of the Furnace Creek Formation, it seems likely that the overlying Funeral Formation there is Pliocene and early Pleistocene (?). A Miocene age originally was assumed for the fanglom- erate at the head of Emigrant Wash (Hopper, 1947), but more recently a Pliocene age has been inferred for those deposits on the basis of pollen obtained from them (Axelrod and Ting, 1960). Included in the Funeral Formation at the north end of the Artists Drive fault blocks is a mass of quartzite breccia believed to be a chaotic breccia derived from the Zabriskie Quartzite (p. A25). How it became em- placed remains a mystery. Other blocks of Paleozoic rocks in that area are found along faults and are far removed from masses of the Paleozojc formations that might have supplied them. Perhaps they are blocks of chaos associated with low-angle faulting. The beds mapped as the Funeral Formation in the Salt Creek Hills have been regarded by Curry (1989) as Pleisto- cene on the basis of tracks found in them. In Emigrant Wash the Funeral Formation is at least 3,000 feet thick; it was originally referred to as the Nova Formation (Hopper, 1947). It consists in large part of cobbles and boulders of Precambrian rocks like those on the high part of the Panamint Range; conse- quently, the formation has been thought to have been derived from that direction. However, Axelrod and Ting (1960) report that the formation becomes coarser grained westward and indicate a western source from the direction of Panamint Valley. This interpretation A63 involves major topographic changes like those indicated by the southeastward-thinning gravels in the Furnace Creek Formation in the Black Mountains (p. A60). The Funeral Formation at the head of Emigrant Wash may record similar changes, but I gave the deposit there only cursory examination. On the Artists Drive fault blocks the Funeral For- mation is composed largely of debris from the volcanic formations. The Funeral unconformably overlaps the much-faulted and tilted rocks of the Artists Drive for- mation and includes flows of basaltic lava and some beds of volcanic ash as much as 4 feet thick. It dips west- ward under the playa where a drill hole on the floor of the saltpan opposite Artists Drive encountered 400 feet of fanglomerate with basaltic cobbles believed to be the Funeral. This hole, the log of which is given on page A74, did not reach the base of the formation. The Black Mountains must already have been high ground, shedding debris westward, but the vulcanism was con- tinuing while these fanglomerate beds of the Funeral Formation were being deposited. Along Furnace Creek only about 150 feet of fan- glomerate of the Funeral Formation is exposed in the trough of the Texas Spring syncline and in the fault blocks farther north. A mile east of Zabriskie Point the fanglomerate is composed largely of volcanic rocks, commonly as much as 2 feet in diameter. Northward from Furnace Creek Wash the gravel contains increas ing proportions of Paleozoic carbonate rocks and lower Paleozoic clastic rocks reflecting the composition of the source rocks in the Funeral Mountains. Near Echo Canyon the gravel contains about 70 percent carbonate rocks and 30 percent quartzite; from Echo Canyon north to Nevares Spring the proportions are reversed, carbonate rocks 30 percent, quartzite 70 percent. At Rock Alinement Wash and farther north the gravels are very largely quartzite, only 5-10 percent is carbonate rock. Clearly the Funeral Mountains were in existence and shedding debris into Death Valley when fanglom- erate of the Funeral Formation in this area was being deposited, but the faulting and the downfolding into the Texas Spring syncline shows that much of the up- lift of the mountains, especially the Black Mountains, was later. I assume that the fanglomerate was being deposited while the mountains were being elevated. In the East Coleman and Salt Creek Hills the fan- glomerate contains boulders of coarse-grained granitic rocks as large as 5 feet in diameter. Their source prob- ably was to the northwest, in the northern Panamint Range, like that of the granite and upper Paleozoic cobbles in the conglomerates of the Furnace Creek For- mation (p. A60). A64 Except for these granitic boulders, the fanglomerate is not very bouldery. North of Echo Canyon, for ex- ample, the common large size is 1 foot in diameter. At one outcrop 114 miles from the mountain front (in SE cor. see. 13, T. 27 N., R. 1 E.) a cliff 30 feet high and 30 feet long contains only 30 boulders as large as 1 foot in diameter; that is, only 1 per 30 square feet of outcrop. The common large size of the gravel is 6 inches in diameter, and even these cobbles are few. An outcrop 10 by 10 feet exposed 50 such cobbles; that is, 1 per 2 square feet. Three-quarters of a mile down- stream the gravel is even less coarse and contains only a third as many small boulders. Similar proportions were found along Echo Canyon Wash. At most places the fanglomerate is firmly cemented with calcium carbonate. The cemented layers are sev- eral feet thick and extend for hundreds of feet along the outcrops, especially where the gravel overlies fine- grained sediments so that ground water can be perched on top of the impermeable beds. The cemented layers are particularly thick and extensive in an area extend- ing 2 miles southeastward from Park Village, an area that has many springs. The gravel also is cemented in the axis of the Texas Spring syncline down dip from Travertine Spring and Texas Spring (fig. 2, locs. 2, 3). Where the fanglomerate is cemented with calcium carbonate it is cut by numerous veins of banded calcite, locally referred to as Mexican onyx. These veins, which generally parallel the principal faults, are a few inches to a few feet wide and may be several hundred feet long. Trace elements in the veins are the same and in about the same amounts as in the travertine mounds at springs. Analyses are given in table 20. Caliche in the Funeral Formation in the Artists Drive area is mostly gypsum rather than calcium car- bonate. The surface of the fanglomerate has developed smooth desert pavement (fig. 50), a surface described more fully in connection with the No. 2 gravel where it is best developed. The fanglomerate is so faulted, folded, and dissected that its remnants no longers retain their fan form. In the Park Village area, for example, the fanglomerate is in a fault block that forms a ridge about 350 feet high and trends north roughly along the contour of the fans that rise eastward to the Funeral Mountains (figs. 53, 62). Drainage down the fans has become incised across the ridge, and younger gravel deposits lie on both sides of it. The incised gorges are older than Lake Manly (p. A69). At the Salt Creek Hills the Funeral Formation is raised in a faulted structural dome having at least 250 feet of structural relief. Salt Creek is incised across this dome. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA In both these areas fanglomerates of the Funeral un- conformably overlie deposits of late Pliocene age that are uplifted more than the fanglomerate. The defor- mation clearly began in Pliocene time and then con- tinued. Very likely the deformation progressed in small increments over a long period of time, and the drainage probably is antecedent-or anteposed (Hunt, 1956, p. 65)-across the uplifts. That is to say, the drainage incised across the uplifts probably was dammed repeatedly as uplift progressed, but the ponded streams overflowed along their old channels. The re- sult is aggradation upstream from the dam, giving some suggestion of superposition in that direction ; but down- stream the drainage would be antecedent or consequent. QUATERNARY SYSTEM PLEISTOCENE DEPOSITS NO. 2 GRAVEL The No. 2 gravel unconformably overlaps fanglomer- ate of the Funeral Formation along Furnace Creek Wash and differs from it in being less well consolidated, more bouldery, and less faulted, tilted, and dissected, so that it retains its fan form. The No. 2 gravel lacks calcite veins; but it does have layers cemented with calcium carbonate, although these are thinner and less extensive than in the Funeral Formation. The No. 2 resembles the Funeral in having surfaces mantled with smooth desert pavement composed of disintegrating blocks, slabs, and flakes. The No. 2 gravel can be distinguished from the younger ones, Nos. 3 and 4, in at least six ways: 1. The No. 2 gravel forms the highest benches above the present drainage. 2. The low parts of the No. 2 gravel are overlapped by the younger gravels. 3. The No. 2 gravel is more bouldery than the younger ones. 4. The No. 2 gravel is more cemented. 5. The surface of the No. 2 gravel is smooth desert pave- ment, whereas the younger gravels have rough surfaces. 6. The streamworn cobbles and boulders on the surfaces of the No. 2 gravel have disintegrated to produce a new crop of angular rock fragments. Along the foot of the Panamint Range and in front of the Funeral Mountains the No. 2 gravel forms benches 100 feet above the present washes (pl. 2). Toward the saltpan these benches commonly slope more steeply than the average slope of the gravel fans, and their lower edges extend under and are overlaped by the No. 3 and No. 4 gravels (fig. 64). STRATIGRAPHY AND STRUCTURE The No. 2 gravel contains considerable sand, but mixed with it are boulders many feet in diameter, as well as pebbles and cobbles of intermediate size. The larg- est granitic boulders are on the fans of Hanaupah and Starvation Canyons where many are more than 10 feet in diameter and some are as large as 30 feet. They are distributed along the entire length of the fan, down to 250 feet below sea level. These abundant large boulders may indicate exterior drainage at the time they were deposited. No matter what mechanism is considered, vast amounts of water would be required to deposit such coarse debris in suffi- cient volume to build fans 6 miles long and 3 miles wide. With so much water, there should have been a lake, and had there been a lake, the bouldery deposits should have formed deltas, not fans. These coarse deposits in such large volume, though, pose no problem if Death Valley had exterior drainage to the south at the time they were deposited. On the fans of Hanaupah and Starvation Canyons granitic rock comprises about 20 percent of the gravel. Sixty percent in quartzite, and about 10 percent is car- bonate rocks and argillite. On Trail Canyon fan, where the gravels contain about equal proportions of quartzite and carbonate rocks and only minor amounts of igneous and metamorphic rocks, the common large size of boulders is 2 feet in diameter, although some are 6 feet. On Johnson Canyon fan, where the gravel consists of about 80 percent quartzite, 10 percent monzonite, and 10 percent carbonate rocks A65 and argillite, the boulders are small like those on Trail Canyon fan. Northeast of Cottonball Basin the No. 2 gravel con- tains considerable salt, more salt than occurs in the gravel around the other sides of the saltpan. This is attributed to the winds transporting salt northeastward from the saltpan. A gravel-filled former channel of Furnace Creek is well exposed along Furnace Creek Wash (fig. 46). Opposite Zabriskie Point this fill contains almost 90 percent carbonate rocks. - This differs from fanglomer- ate of the Funeral in the area, which here contains a high proportion of volcanic rocks; it also differs from the fan gravels derived from the Funeral Moun- tains north of here, which contain a high proportion of quartzite. The principal source of this channel fill apparently was in the southern part of the Funeral Mountains; the principal source of fanglomerate of the Funeral in the area apparently was the northern part of the Black Mountains. The downcutting that followed deposition of this channel gravel probably was caused by structural uplift of the wash relative to the present Furnace Creek fan, because the surface of the gravel fill, if projected, would extend about 50 feet above the fan. This uplift prob- ably is the same deformation that raised the small gravel terraces along the west foot of the hills just north and just south of the mouth of Furnace Creek (fig. 47) and that produced hanging valleys along the foot of the Black Mountains farther south (fig. 77). FicurE 46.-Gravel fill in former channel of Furnace Creek Wash. The channel is eroded in Furnace Creek Formation (Tf), which dips steeply northeast (right), and the bottom is below the level of the present wash. The fill (Qg) is about 50 feet thick. View is north in tributary to Furnace Creek Wash opposite Zabriskie Point. A66 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA FicurB 47.-Escarpment along the front of the north end of the Black Mountains a quarter of a mile south of Furnace Creek. 'The terraces, capped with No. 2 gravel, have been faulted upward about 75 feet. Other deposits of No. 2 gravel occur in the canyons in the Panamint Range, considerably upstream from the gravel fans. There are sizable remants in most of the canyons, and these remnants are 50-100 feet higher than the present canyon bottoms. Evidently the can- yous had been eroded to their present depth before the gravel was deposited, then buried to a depth of 100 feet or more with this gravel and subsequently re-excavated. Interbedded with the gravel in the south fork of Six Spring Canyon is a bed of volcanic ash as much as 4 feet thick. Drainage on the No. 2 gravels reflects the fan form of the remants of that gravel. Washes are parallel and consequent. Moreover, washes that are a few hundred feet wide and more than about 10 feet deep commonly have low terraces of No. 3 gravel along them. Karstlike solution features are common where Terti- ary rocks are overlain by the No. 2 gravel, such as near Furnace Creek Ranch. On the west side of Death Val- ley, along the north edge of the wash a mile north of Hanaupah Canyon, there is a depression 15 feet deep, locally referred to as "the crater" in the No. 2 gravel. The depression has a floor of silt about 50 feet in diam- eter and 60 feet higher than the wash which is on the south side of the depression. This depression prob- ably is due to water seeping from the gravel bench to the wash, dissolving calcium carbonate caliche from the gravel, and allowing the gravel above to collapse. The fan of No. 2 gravel at Starvation Canyon has three tremendous ridges radiating down the fan and evidently marking old mudflows (fig. 48). The ridges, large enough to show on the topographic contours, are 2-3 miles long, 500-1,000 feet wide, and 50-75 feet high. Their volumes are 8-25 million cubic yards. Each ridge has a narrow crest with a wash along it; the sides are strewn with huge boulders and slope evenly to the adjoining fan surfaces. The surface of the No. 2 gravel is smooth desert pave- ment. Boulders and cobbles on these surfaces have dis- integrated to produce an entirely new crop of angular rock fragments-the kind that no longer are properly classified as water worn. They are better described as blocks, the equivalent of boulders; as slabs, the equiva- lent of cobbles; and as flakes, the equivalent of pebbles (Woodford, 1925, p. 183; see also Pettijohn, 1949, p. 12-15). These desert pavements composed of slabs and flakes are the smoothest in the valley. On a typical surface on the No. 2 gravel, and also on fanglomerate of the Funeral Formation, 75 percent or more of the boulders and cobbles have lost their original roundness. On some surfaces practically every boulder is fractured or crumbled. Although the kind and de- gree of weathering varies considerably, depending on the composition and texture of the rock, no rock has been spared, whether coarse or fine grained (fig. 49). The disintegration of these gravels is most advanced where the gravels extend into the zone of abundant salts. Striking examples of the effectiveness of salts in accelerating disintegration are provided by the concrete bases of bench marks along the highway crossing the _saltpan and extending along its west side. Concrete in locations that are frequently wetted with saline water is badly disintegrated. The disintegration is less ad- vanced at equally saline locations where the wetting and drying is less frequent, and the concrete still is sound at locations that are dry and not notably saline. But disintegration of stones on the No. 2 surfaces is general and not confined to the toes of the fans which aro impregnated with salts. The disintegration occurs all the way to the mountains. It is a near-surface phe- STRATIGRAPHY AND STRUCTURE nomenon because boulders and cobbles more than 2 or 3 feet deep in these deposits are sound. The desert pavement consist of a single layer of closely spaced blocks, slabs, and flakes as illustrated on figure 50. Beneath it is a layer of vesicular sand and silt, 1-6 inches thick, containing as much as a tenth of a percent of salts. Gravel under this layer is cemented with salt and iron oxide. Stones forming the pavement creep down the slope, as is indicated by terracettes (fig. 51) and by trains of slabs extending downslope from blocks that are disintegrating. An individual pebble on the desert pavements is sub- jected to three very different microclimates. The up- per surface, exposed to maximum temperature and max- imum temperature change, in general is being eroded, as shown by partial removal of desert varnish. Around the side of the pebble is a narrow band where the tem- peratures probably are less extreme and where there is maximum wetting, by dew as well as by other surface water. This narrow zone has a dense population of 1M Profile across mudflows _ HORIZONTAL SCALE X 2 VERTICAL SCALE X 10 par A§ Es tao % A/ = bre 11:15 AP j? % > s The 48.-Map and profile across mudflows on Starvation Canyon fan. A67 microorganism, and even some megascopic ones-algae. The underside of the pebble has moderate temperatures and soil moisture condenses on it. This surface is red with iron oxide. In an environment like Death Valley these differences in microclimate are extreme, and prob- ably are an important factor in the continued weather- ing and disintegration of the No. 2 gravels. Desert pavement may develop in a very short time. Where the ground consists of loose sand or silt contain- ing pebbles, only a few windstorms are needed to blow away the fine materials and collect the coarse as a pave- ment of pebbles. Such very young pavements do not have a silt layer under the pebbles. On some of the archeological sites, however, a silt layer one-fourth inch thick occurs beneath the layer of pebbles. The thickest silt layer that I found on pavement developed on No. 3 gravel is about an inch, but no systematic search for thicker layers was made. The silt layer under the peb- bles on the No. 2 gravel commonly is a few inches thick. The evidence is pretty good that the thickness of the 11650 -| 36°10 f {36°07 1 2 MILES 1 I CONTOUR INTERVAL 40 FEET DATUM IS MEAN SEA LEVEL Topography from U.S. Geological Survey topographic quadrangle ; Bennetts Well, 1952. A68 FiqUrE 49.-Boulders disintegrating to slabs and flakes on the oldest gravel deposits (Funeral Formation and No. 2 gravel). Upper, Quartzite boulders commonly break into slabs along transverse fractures. Lower, Massive rocks like the porphyry boulders on the fans of the Hanaupah and Starvation Canyons exfoliate and crumble. silt layer on old surfaces is greater than on young ones. The terracettes on the No. 2 gravel commonly have treads 1-5 feet wide and risers 1-6 inches high (fig. 51). The surfgee inch or two on the treads commonly contains 1 percent or more of water-soluble salts whereas the adjacent stable surface without terraces contains as little as 500 parts per million of water-soluble salts. These ground patterns are described more fully by Hunt and Washburn (in Hunt and others, 1965). Only once during the 6 years of the field study did I witness a rain that thoroughly soaked into the gravel. On February 16, 1959, 1 inch of rain fell in 24 hours, and the silt layer under gravel pavement on the Hanau- pah Canyon fan became soaked. Walking on the pave- ment involved walking ankle deep in mud, because footsteps sank into the mud underlying the gravel of the pavement. Frequent soaking like this would accel- erate mass-wasting processes, but there is evidence that these processes operate very slowly under the present GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA FiGurR® 50.-Desert pavement, foreground. View west from Park Vil- lage fault block. Weathering of boulders and cobbles at the surface has produced a new mantle of blocks, slabs, and flakes, forming a smooth desert pavement in which the stones are closely spaced but barely or not at all shingled. Photograph by John R. Stacy. F1GURE 51.-No. 2 gravel with desert pavement interrupted by terracettes. STRATIGRAPHY AND STRUCTURE climate (Hunt and others, 1965). Most of the terrac- ettes and other patterned ground probably are relicts from a wetter period. DEBRIS AVALANCHE A large avalanche of blocks and rubble of Precam- brian rocks is at the foot of the Black Mountains midway between Badwater and Copper Canyon. At the source, above the debris avalanche, is a huge scar be- tween 2,000 and 2,500 feet in altitude; the volume of the avalanche must be greater than 5,000,000 cubic yards. No lake features were recognized across the front of the avalanche, but its lower part has been displaced by faults that seem to antedate the Pleistocene lake de- posits. - It is composed of blocks of Precambrian rocks tens of feet in diameter in a matrix of rubble of similar rocks. LAKE DEPOSITS Late Pleistocene lake features in Death Valley are few, small, and not at all distinct. 'That Death Valley had contained a Pleistocene lake was stated widely long before positive evidence of its existence had been found. Before 1900 both Russell (1885, 1889) and Gilbert (1890) had referred to a former lake in Death Valley, and Bailey (1902) named it Death Valley Lake. Yet, as late as 1914, Gale, who was a student of the Quaternary basins, wrote (1914, p. 401) : In spite of the immense drainage territory tributary to Death Valley there is no evidence that the waters from these streams ever accumulated in it to sufficient extent to form more than a shallow inconstant lake. A search for traces of any upper lines around the slopes leading into Death Valley has failed to reveal evidence that any considerable lake has ever existed there. Not until 1926 was clear evidence found that a late Pleistocene lake had flooded Death Valley. Levi Noble identified the strand lines on the basalt hill, later known as Shoreline Butte, at the south end of Death Valley, and discovered other strand lines in the cove northeast of Mormon Point (Noble, 19262, p. 69). The lake or lakes that produced these features have since been re- ferred to as Lake Manly (Means, 1932; Blackwelder, 1933, 1954). Small embankments of shingled gravel, evidently beach deposits or near-shore bar deposits of late Pleisto- cene lakes, are numerous but widely scattered along the north and east sides of Death Valley at altitudes as high as 380 feet above sea level; small horizontal terraces that may be wavecut features occur several hundred feet higher. Similar deposits or beach sears are curi- ously lacking along most of the west side of the valley ; in fact, they are known at. only 2 localities 40 miles apart-on the basaltic hill between Tucki Wash and Blackwater Wash and on Shoreline Butte at the south end of Death Valley and south of the area mapped. A69 FiGurs 52.-Gravel bar of late Pleistocene Lake Manly resting on older fan gravel 2 miles north of Beatty Junction. Sketch from photograph. 'The most accessible and best developed gravel bar is exposed along the highway 2 miles north of Beatty Junction. This bar (fig. 52) extends nearly a quarter of a mile east from a hill of Miocene(?) rocks which formed an island at the time the bar was built. The bar, 500 feet wide and 20 feet high, is composed of well-sorted, shingled, and crossbedded gravel, most of it an inch in diameter or less, and not at all like the poorly sorted fan gravels. 'The top of the bar is nearly level; it is 150 feet above sea level. The deposit narrows and then eastward. Other less well-developed lake gravels crop out below sea level a mile south of the bar. These and all the other gravel deposits of the late Pleistocene lakes are composed of firm pebbles showing no sign of disintegration. - The pebbles commonly have a weather- ing rind and are stained with desert varnish. Three miles southeast of this bar is another well- developed one forming an arcuate deposit half a mile long and 500 feet wide, resting on a bench of No. 2 gravel. The bar curves through an arc of 90°. The gravels are shingled, crossbedded, and usually about an inch in diameter, like those in the bar above Beatty Junction. The foreset beds in the gravel dip 10° NW. The top of this bar is nearly level and is less than 100 feet above sea level. No other shoreline features were found between this bar and the one near Beatty Junction. The temptation is strong to assume that the 2 bars, which are similar and highly exceptional features in this area, were formed at the same time and that the difference in level is attributable to 50 feet of postlake faulting or tilting between the 2 localities. Other shoreline features are exposed along the west face and top of the ridge of Funeral Formation in the fault blocks north of Park Village. Small deposits of shingled gravel are associated with long narrow ter- races that, in part at least, are sears of old strand lines ATO GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA FicurB 53.-View east to Park Village fault block of Funeral Formation showing long narrow terraces that are interpreted to be scars of strand lines of late Pleistocene Lake Manly. (fig. 53) ; some similar terracettes, however, are attribu- table to mass washing. Most of the strand lines and associated deposits along the west face of the fault blocks are between sea level and 75 feet above sea level. Strand lines and associated deposits also occur on top of the fault blocks at 150 feet above sea level. Some of these lake deposits extend into the gorges across the fault block, showing that these gorges antedate the lake. Another deposit of lacustrine gravel is at the north end of the Artists Drive fault blocks, and at the same level northward and southward from this deposit are narrow terraces, evidently wave cut, impressed on tilted strata. The deposit of gravel and the terraces are at sea level. Stone artifacts at this location have been in- terpreted to indicate human occupation in Death Val- ley at the time of the lake (Clements and Clements, 1953), but this interpretation is doubtful. No un- equivocal artifacts have been found within the gravel deposit; the unequivocal artifacts are part of the desert pavement on top of the gravel and are therefore younger. Moreover, these artifacts are typologically quite like those characteristic of Recent occupations (A. P. Hunt, 1960). In foreground is No. 3 gravel. Along the steep front of the Black Mountains from Badwater south to Mormon Point are numerous dis- continuous horizontal embankments of gravel cemented with calcium carbonate. Most of these embankments aro between sea level and 200 feet above sea level, but some are even higher. How many of them are truly lake deposits is problematical. Well-sorted shingled lake gravel is exposed overly- ing a fault block of the Funeral Formation, at the north end of the steep part of the mountain front, about mid- way between Badwater and Bridge Canyon. The lake gravels are composed mostly of Precambrian rocks, whereas the fanglomerate contains, in addition many volcanic rocks. The lake gravels are better sorted and less well cemented than the fanglomerate. Foreset beds in the lake gravels dip north-northwest as if there had been northward shore drift at this location. The lake gravel intertongues with the lower part of a colluvial deposit that overlaps the lake beds. This colluvium is cemented with gypsum rather than calcium carbonate. Other lake gravels are exposed at Mormon Point and extend 114 miles eastward. These deposits, the most extensive lake deposits of gravel exposed in the valley, STRATIGRAPHY AND STRUCTURE overlie the No. 2 gravel. They are at sea level and as much as 200 feet above sea level. The only lake deposits and geomorphic features at- tributable to lake processes found thus far on the west side of Death Valley are at Shoreline Butte (Noble, 1926a; Blackwelder, 1933, 1954) and at the basaltic hill between Tucki Wash and Blackwater Wash. At Shore- line Butte are numerous shorelines between the foot of the butte at 150 feet below sea level nearly to the top, at 400 feet above sea level. The hill between Tucki Wash and Blackwater Wash has two shorelines. The lower one is an embankment of gravel at an altitude of 160 feet. Its gravel consists of basalt and of Paleozoic rocks derived from the fans in Blackwater Wash. The embankment thins northward, and the gravels, which are 2-3 inches in diameter at the south end of the hill, be- come finer northward (1 in. in diameter). This em- bankment is cemented by deposits of calcium carbonate that forms spotty masses of travertine. Both the gravel and the travertine are distributed irregularly through a vertical range of about 20 feet, but they can be followed discontinuously from the south to the north end of the hill. On top of the hill, in the saddle between the peaks, at an altitude of 380 feet, is another small patch of shingle gravel derived from Paleozoic rocks. Although the gravels from Paleozoic formations were drifted northward by shore currents across the face of this hill, the much lighter scoriaceous basalt from this hill does not occur as shore drift extending northward across the fans of No. 2 gravel in Tucki Wash. It would appear that the lake deposit is older than the No. 2 gravel, but this probably is not so. The surface of the No. 2 gravel in Tucki Wash may be younger than the lake, and if so, embankment deposits of basaltic scoriae that may have extended northward across the No. 2 gravel could have been destroyed. The relationships at Tucki Wash illustrate the highly uncertain age of these lake deposits with respect to the No. 2 gravel. At 2 locations, Mormon Point and 2 miles north of North Side Borax Camp, the lake deposits rest on and must be younger than the No. 2 gravel. Nowhere has the reverse relationship been found. Moreover, the gravels at the surface of the No. 2 are much more weathered and disintegrated than those at the surface of the lake deposits. The difference in weathering is the kind that elsewhere in the West has been successfully used to distinguish pre-Wisconsin deposits from Wisconsin and younger ones. But why, then, are there no lake deposits or other shore features impressed on the many miles of No. 2 gravel exposed along the west side of Death Valley ? Eval The west side of the valley was the lee side of the lake, and deposits there could have been thin and discontinu- ous. Even so, it is difficult to believe that all trace of them would be destroyed. Yet the evidence at the two localities where the stratigraphic relationships are cer- tain, and the more general evidence about the difference in weathering, suggest that the No. 2 gravel every where is older than the Lake Manly deposits. Lake Manly has been correlated with the Wisconsin (Tioga and Tahoe) stages of glaciation in the Sierra Nevada (Blackwelder, 1954; Clements and Clements, 1953), which correlate with stages of Lake Bonneville and Lake Lahontan. This correlation is supported by the fact that the pebbles on the surface are not disinte- grated but are firm-suggesting an age no older than Wisconsin-yet many have developed a weathering rind that suggests an early Wisconsin (Tahoe) age. The slight erosion and sedimentation record of Lake Manly may mean that the lake was of brief duration, and its level may have fluctuated rapidly. Whatever the cause, this California lake left one of the least distinct and most incomplete records of any Pleis- tocene lake in the Great Basin-another California superlative ! The water that accumulated in Death Valley to form Lake Manly has been attributed to overflow from a lake that formed in Panamint Valley when there was over- flow from Searles Lake and the other lakes headward along the Owens River valley (Gale, 1914, p. 402; Blackwelder, 1954, p. 57). The overflow into Death Valley would have been by way of Wingate Pass and down Wingate Wash, but no trace remains of the floods that must have descended the wash to form Lake Manly. Perhaps much or most of the water came from the south, by way of the Mojave River and Soda Lake. This hypothesis has some support in the distribution of spe- cies of desert fish in the several drainage basins. Owens Valley has two genera of desert fish, Siphateles and Catostomus, that are said to have come from the Lake Lahontan area ; Siphateles also occurs in the Mo- jave River (Miller, 1948). Neither of these genera has been reported in the Death Valley-Amargosa River area. - Further, a Cyprinodon that occurs in the Owens River, C. radiosus, is said to be more closely related to the Colorado River cyprinodonts than are any of the three species living in the Death Valley-Amargosa River area (Miller, 1948). This distribution of species suggests that the drainage system from Owens Valley to the Mojave River bypassed Death Valley. Flooding from the direction of Soda Lake also is suggested by considering the possible tilt of the Lake Manly deposits. The principal deposits are at sea level in Mesquite Flat and along the north and east. sides of ATZ Death Valley as far south as Artists Drive, but they are 200 feet above sea level on the west side opposite Fur- nace Creek. They are 200 feet above sea level at Mor- mon Point, and there are large deposits as much as 300 feet above sea level at Shoreline Butte. At all these places there are higher shoreline features; the altitudes given refer to the principal deposits. They suggest an eastward tilting of 200 feet and a northward tilting of 300 feet. If such tilt is real, the lake probably extended to Soda Lake, which is where Russell (1885, pl. 1 ; 1889, pl. XVI), Gilbert (1890, pl. 2) and Bailey (1902) origi- nally thought it went, and which was still considered a possibility by other later workers (Blackwelder and Ellsworth, 1936, p. 462). VALLEY FILL Gravity and magnetic surveys indicate that the fill in Death Valley has a maximum depth of about 9,000 feet near the west side of the valley a short distance south of Bennetts Well (p. A108). Drill holes a thousand feet deep near Badwater and in Cottonball Basin show rather uniform alternations of mud and salt to the bot- GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA tom of the holes (table 19), and assuredly the upper thousand feet is Quaternary. I assume that about a third of the fill is Quaternary and that the rest is Tertiary. The fill in Badwater Basin thins southward and northward. Opposite Artists Drive the fill is only about 4,000 feet thick. A drill hole in this area en- countered only 50 feet of mud and salt and then went into basaltic conglomerate to a depth of 500 feet before the hole was abandoned. This conglomerate is corre- lated with the Funeral Formation that rises eastward onto the fault blocks at Artists Drive and there uncon- formably overlaps the older volcanic rocks (p. A63). The fill thickens again northward under Cottonball Basin, thins under the Salt Creek Hills, and thickens again under Mesquite Flat. Logs of the three deep holes are given in table 19. Logs of some shallow holes drilled by the U.S. Geolog- ical Survey in connection with the search for more potash deposits during World War I are given in Hunt and others (1965). 19.-Logs of wells drilled by Pacific Coast Boraz Co. [Drillers' logs revised from mud samples] Description Depth (feet) ‘ Description Depth (feet) Well 1, 234 miles northwest of Badwater, E}4 sec. 30, T. 25 N., R. 2 E. (projected) Surface . 0 ;- 4 Hard salt_. _.... _ lc i LCL 126% - 132 Alternating salt and mud.__.._.__._L__._____ ___ 4 -- 20 Black mudi L 2222 n inates bee 132 - 134 Hard ___ 31 {rr ao 20 - ~ 28 Medium-hard black mud and salt_________. 134 - 136 Hard salt; occasional streaks of black mud _ . 28 -- 38 Very hard le ce2 00020 136 - 138 Hard salts ls, t _L POs li __ 38 -<. .\ 41 plack l On le 138 - 140 (co nll 41). = + 4114 |f Medium-hard 810 140 - 142 Hard ic {t_ t 414 - - 48 Soft black mud este ct Ls 142 - 143 Thin streak soft black mud.________________ 48st ~~ :__ Hard salt... lll. v8 tact 143 - 154 Hard salt. n_ _ 48 -- 50 Soft black mud. c 154 - 158 Soft black mud, containing salt crystals.... 50 - 53 Yery hard cect cs 155 = 100 Hard stl __ 53+ ~> '55 Hard and soft streaks; particles of reddish Yery hard c_ u_ 55 - - 59% clay. shane ont ece s 160 - 163 Soft black mud.... il- - 59% - - 60% || Hard salt and soft streaks of clay.._.______ 163 - 166 Very hard salt; streaks of black mud and Soft gray clay and salt crystals___________._ 166 - 168 brown _ 604 - - 62 Soft gray clay and salt, mostly salt________. 168 - 170 Very hard salt; one small streak black mud. 62 < 65 Nery hard salt - ed 170 - 171 Hard co mes Alles 65 -: 67 Softer material; clay and salt; gray and Soft black mud 67> < ~ 68 reddish scl? . 171 - 1734 Hard walt. cn IM. LOE ~- 68. => 79 Hard §alt? . surely = < 173l4- 175 black mud 72 -- 72% || Softer material; some gray clay.. 175 - 176 Tard _E -_ [N ct 72% - - 75% || Hard layers of salt and small streaks gray No _ Sca o jug. 75%- 81 ClaY 21 .- kane ans 176 - 190 Hard kerk nite cause ab 2 81: =- 89 Hard streaks of gray mud and salt_________ 190 _- 210 Mud and salt 89 -/ 02 Hard salt; a little gray mud-_______________ 210 - 215 Hard salt.: _._ Omi 0" 92 --'. 04 ello cease: {uveal 215 - 218 Mud and _ {oal .c 9+ - / 100 Hard salt; small streaks of gray clay________ 218 - 225 Tard .ll otc 0 st _ (:l XC, 100: -': 103 Hard salt o4 cL. c :. can rw i s Rage 225 - 226 Roft black mud ifa 12) 103 - 106% || Hard salt and streaks of gray mud and clay__| - 226 - 239 Hard salto t os tol la lay. 106% - 107 Same material; clay on the increase.... 289 - 241 Very soft black mud; salt erystals__________ 107 - 109 Thin strata; alternating hard salt and dark Yery hard galt -_. at Pon _C 100 ~ 'i14 muds! cl. clears 241 - 246 Softer salt with some black mud. ..__._____. 114 - 115% || Grayish mud; very little salt. _____________ 246 - 250 Very hard salt; occasional streaks of soft Salt and mud, principally salt____________-. 250 - 255 black l c Acct 115% - 118 Soft clay; very little 255 - 260 Salt mixed with black mud and a little red Alternating salt and dark gray clay; some play ».. .t __ gita e 118 = 123 black can ul llc :t (.g 260 - 265 l onn lero accel. 122 -> . 125 Dark-gray clay; thin (2-in.) streaks of salt___| 265 - 269 Soft black mud_--..".: "sf _~"___ "[M 125 - 126% || Dark-gray clay; very little salt____________._ 2069 .- 272 STRATIGRAPHY AND STRUCTURE 19.-Logs of wells drilled by Pacific Coast Borax Co.-Continued A73 Description Depth (feet) Description Depth (feet) Well 1, 214 miles northwest of Badwater, E}4 sec. 30, T. 25 N., R. 2 E. (projected) -Continued Soft gray clay and salt crystals___________._ 272 <- - 273 Same material; clay alternating gray and HAT =- ne eee r ase awan. 273 - 274 DrOWH >> 631 - 636 Gray clay and dark mud, almost black_____. 274 - 277 Black salt mud with gray and brown clay; Clay and 277 - 278 clay Increasing. . 636 - 650 Hard : 278 -- 280 Gray clay with streaks of black mud and 650 asp Layers of salt and gray mud_______________ 280 - 284 brown Clay -=- ens - Gray clay with smaél streaks of salt_______. 284 - 3&5) Grgy clay1w1th more black mud; streaks of > 4 Gray and black mud _-_._-.-.-_.;.-__...____.. 285 - town clay. ec - 131231; mud...l ____________________________ 333) x 33; Clay, alternating gray and black, with some *> A7 Very hard - ...... .L. _ anns e> - Gm}; clay; few salt crystals________________ 292 - 294 Same material; probably some anhydrite (esp Tough Meck day Ae alc: :" ol Apion So mesa maar cnt oo toc noel." - 685 mo. mit _ dolles. - Harder material, black mud and clays -____| 685 - 605 Very hard 200" 305 - 308 ticky and soft black mud and clays______ _. - Gm}; clay with fine salt erystals____________ 308 - 312 Harder material, black mud and clays---__. 697 - 700 Hard 312 -> 317 Soft Diack clay. cl.. 700 - 706 Gray clay and fine salt-....:__:.__..__._._ s17 < 318 Mixed clays; no galt... 706 - 710 Hard salt with "some coarse brown and gray Brown black clays; varying soft to tough-___|\ 710 - 730 Play" 2. re ine Pare ce eee bonne baw cn anes 318 - 328 Gray salty clay; some streaks black and Gray clay: some 328 - 329 > brownluul ------- duas take. 730 - 742 sana ow . - Jof aA RAT ct"! 1 m 83; mud and clay; a little sait and black | - ""- ""~ || Hard salt; layers gray clay and black mud..) 748 - 751 clay o es 339 - 342 Hard salt with clay; slow drilling._._______. 751 - - 764 yellow lay __. _.. cal _ Lr n= 342" - 345 Hard salty clays; gray and black, tough.... 764 - 766% Hard sait; streaks of gray mud____________| 343 _ 34g | Same material, with some brown clay.. ___| - 766%- 767% Hard salt and yellow $46" - 349 Black mud and gray clay; softer; mud in- yerk- 785 Hard salt; little gray mud and clay._______. 349 - 350 Blcriasmgd-T ----- ftacaip nt NE as 200 Hard salt; gray mud and clay increasing.... 350 ' =' 359 H'acd [gilt {NYE ycla ea 3d yn—III I. afew fray." Gray and black mud; some salt____________ 359 - 360 a; Gusts of gypsumy H ase §00._ ~' ats gig}, 33g 2231321355153, """""""""""" 32g > ggg Hard gray clay, salty; thin strata of black re T A aw. upa alena. arn't and brown clays, showing a few fragments ray mud and 2000... 370 - 375 f Net s P sig: : onn saity tayo " $e 2) $BQ - | game material, but harduess sarving. ... ._. 815 - 830 Same material], with streaks of black mud... 5900 - 804 Eggsfllgéw‘th clays and mud___________-.- 22g a gig Salty brown ul." 394 - 400 me ~~ > Same material, but softer. ._._._____________._ 400 - 410 Egcfi $33 with some gray clay and salt... gig s gig Salty brown clay, streaks of gray clay______ 410 - 415 Blagk nud radian.. nica crf ti"" - sip Brown mud, some particles of black mud... 415 - 428 Hard salt; gray brévI'h—fajfi A black cla “y """ #49 ~ S54 A ¢ , brown, and black clay... films mitenal. with a few salt crystals.___ _- 2323 T 132 Hard gray, clay with layers of other clays and ine mnd and salt ca chris E muds; a little crystal 854 - 863% Soft brown mud and salt crystals; a little Softer _c certain.: 7. glzhmberltm srv hard. streaks: a hitle olan. 48306 < 487 Hard gray clay with some black and brown. 8634 - 865 Salt; some very hard streaks; a little glau- Same material; shows white fragments of bente"""""“""““.““““"‘.'" 437 - 440 cle ence ane ae 865 - 878 Hard salt; some gray clay; a little glauberite.| 440 - 442 Hard salt; gray-brown clay and black mud._._| - 878 - 887% Hard salt; gray and black clay; notable Hard gray clay; streaks of brown clay and amount of __ 442 - 443 erystals of 24 887% - 890 Nard salt; gray 443 - 444 || Same material, with black streaks__________ 890° - 900 No 220200000 411. - A40 Same material. At 904 ft, about 1 in. very Brown clay and hard 440 -. 447 parar... le [ltt ~ 900 ~ ~- 004 Same material, but softer; some gray clay. 447 - -' 448 Hard gray clay; streaks brown and black; Hard salt; gray, brown, and black clay. >.." a. c a> t te-} 904 - 909 Hardness YAry ME- 445 - 405 Salt; gray mud; black.clay 909 - __ Same mate-Hal, but very hard.. 465 - 468 Softer material; gray clay _-_.-._--__-__--__ 909 - 911 Soft mat_er1al; brown? gray, and black Clays; Black, brown, and gray 911 -> 921 black 405. - 451 Salt; tough gray, brown, and black clays____| 921 - 922 Hard salt and clays, brown, gray, and black. 481 - 484 Cray and black clay. .. cll... "2 922 - 928 Hard salt and gray clay.._______________._. 484 -/ 405 Harder material, a little salt_______________ 928 - 929 Salt with gray, brown, and black clays; hard- Black and eray clayc_llllllnnl n 929 - 937 ness 495 - 519 Black mud-2__. 'll _ ol eI wir} 937 - 943 Clays, gray, brown, and black; some salt___. 519 -.- 528 Black and gray mud; 943 - 945 Hard salt; gray, brown, and black clays____. 523 - 526 Del Ce raf amt! ods / => gss Hard salt; black and brown-muds ---------- 526 - 528 Gray, black, and brown 958 - 960 Same material, black muds increasing.__-_-- 528 - 530 Gray and black 960 - 973 Same material, but softer. 530 - 536 Gray and black clay and salt; a few fragments Salty black clay; streaks of brown clay. __ 536 - 545 of lo dne loi eli 973 - 978 Same material, but brown clay decreasing.._| 545 - 556 Gray and black clay; a very little salt; a few Salty black mud; some little streaks of clay__| - 556 - 625 fragments of gypsum._........-.......... 978 -1, 000 Stiffer clay, and black mud________________ 625 - 631 Gray clay c seo eee cae 1, 000 -1, 000 Deptivof 1, 000 776-623 O-66-6 ATA GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA TaBus 19.-Logs of wells drilled by Pacific Coast Boraz Co.-Continued Description Depth (feet) Description Depth (feet) Well 2, by highway across the valley, at middle of Devils Golf Course NE} sec. 33, T. 26 N., R. 1 E. Sabes ocr oes ue rene cul a aeon e bole awd 0 /- 0% Softer material; contains some clay_______._. 247 -- ' 248 Brown clay and salt and anhydrite________. 0%M4 - 5 Hard imaterial; no ...l 248 - 249 Brown and gray clay and salt and anhydrite. 5 - 6 Softer material; some brown and light-gray Black bituminous clay, salt and anhydrite; ClaY 2. Lue Z - il aa o can's ole bae a a aa 249 - 251 very hard ...es ere 6 -- 13 ase Pere en Nane ane 251 -> 253 Doll 13 - 14% || Hard cemented sand and gravel.___________ 253 - 255 Same material, with a little brown clay ___. 144 - - 23 Brown clay .... : .c 00 -c iaa aed 255 - 258 Softer brown clay, salt and anhydrite______. 28 - - 26 Hard- cement; a little OL 258 - 260 Hard material, otherwise apparently same _ _ 26 -- 28 Soft material; brown clay and gravel_______ 260 - 263 Soft material, game.. 28 -- 29 pagsalt 263 - 265 Hard material, same.. c=. illus 20: - > 30 Brown clays and gravel. 265 - 268 Salt, with a little brown clay and anhydrite. 30. : ~.* 31 Brown clay and gravel: 208 - 270 A little salt and anhydrite and black and Basalt, apparently two boulders____________ 270 - 271 . L- 31 -- 40 Brown clay; occasionally small boulders__- _. 271 - 273 40 -- 65 Browr clay and 2738 - 275 Same material, but more salt. 65 - -~70 Pasalt boulder... 275 - 276 Same material with less salt, and conse- Brown clay and a little siliceous sand ______. 276 -- 301 quently 70 - . 72 Streaks brown to gray clay________________ 301 - 307 Black clay and very few crystals___________ 12 "< "11 No record- ccc cocoon i s 307 - 311 Black and brown clay, with a little salt and brown 311 - 421 anhydrite . ce. cre 77 =..90 Yellowish-brown clay. 421 - 432 Black clay, with very little salt and anhydrite, Same material with a little fine sand ______.- 432 - 438 and a few tufts ulexite (cotton ball) ______. 90 - 100 Brownish-yellow 438 - 459 Black and gray clay; crystal strain _ _______._ 100 - 120 ed clay "n cy ek Suv n iaa d roi a owe 459 - 462 Harder material; a little calcium carbonate Red clay; a little yellow clay_____________._ 462 - 465 Appears as a cement_.L____._______L____ 120 - 121 Brown, red, and yellow clays______________ 465 - 467 Partly cemented black clay________________ 121} - 120 Brown and gray clay, alternated ___ 467 - 471 Hard material; igneous breccia, principally Mostly gray clay.... c. cell ul 0s 471 - 481 basalt, with a little clay and limestone Dark-brown clay and particles of quartz ___ 481 - 483 fragments, all more or less cemented with gan on 483 - 493 calcium 129 - 130 Dark-brown clay; a little sand; possibly fame material, but softer.: _.__..._.._.~.. 130 - 133 glightly comented . 493 - 496 Same material, but Hard. 2} 133 - 150 Hard material; brown clay; no evidence of Black clay and breccia, partly cemented ___ 150 - 155 calcium carbonate, but a little gypsum Breccia of basalt, with a little granite, quartz appears, which may possibly act as a and limestone; cemented in streaks; mostly cementing material. 496 - 499 the size of coarse sand; absorbs much water Gray and brown clay and sand_____________ 499 - 503 from drill hole. .t. 155 /=. 211 Same material; driller reports cement, but Boulders and calcium carbonate cement__._ _. 211 - 2134 none shows in the sample_______________ 503 - 505 A little clay, and softer 218% - 216 Gray and brown clay and sand_______-____._ 505 - 506 Angular gravel, principally basalt__________ 216 - 217 Gray clay; very little sand _. 506 - 508 Cemented gray clay; a few basalt fragments. 217 - 219 No record eel 508 - 512% Hard cemented 219 - 220 Brown clay and slightly cemented gravel___. 512% - 5144 Softer material; considerable clay _________ 220 - 223 Basalt boulder. ._.. 5144 - 514 Hard material; gravel and boulders; cement Gray and black clay; a little fine gravel; soft gradually diminishing 223 - 232 and caving.c2l. ieee eee send 514 - 517 Oravel, as above: 282 - 285 Gravel, principally basalt, a few particles of Brown clay and sand and gravel. __________ 235 - 238 quartz, limestone and gypsum; driller Gravel and small boulders_________________ 238 - 240 reports hard cement, but sample gives no Same material; cemented.__.______________ 240 - 248% evidence iof this.. .-.: [t> 517 - 524 Hard comented gravel-..:._...s..;_.-._:i.. 243M4- 247 Depth of well-: 524 Well 3, Cottonballl Basin, 2 miles northwest of Harmony Borax, SW}4 sec. 32, T. 28 N., R. 1 E. Salt, containing small amount of thenardite Salt and gray clay; a few streaks of black clay. 46 - - 49 (sodium sulfate), borax, and a little yel- Gray and black clay; a little salt__________- 49 - 534 0 :> 2% || Salt; a little anhydrite; some gray clay____ __ 534 - 58 Yellow clay 22". lc ..- cna 2% - 5 Black clay and salt.. $8 '-. Soft salt and yellow clay __________________ de"" Sl§ A| Gray clay and salt. cu: lull. 60- : -;~68 Soft yellow elay.......__________="t il". 5% - 18 Salt and a very little gray clay_______-____- 68 -. =73 Soft yellow clay; a few crystals anhydrite. __ 18. - 19 Salt and a little gray, black, and brown clay. 73 -- 74 Soft yellow 2 _}: LY L 19 -: 81 Gray clay and very little salt_____________- 74. ' T6 Soft yellow clay; a little fine salt and anhy- Salt and a little gray and brown clay; a few ee ceo ne n ere aa enne e cL 31. * ~83 tufts of- 105. = ~79 Black and green clay, with a little salt and Same material, except clay principally brown. 79 - - 83 anfiydrite. .s nell. 88 =' 87 Salt, with a very little clay; a few tufts of Brown clay and salt - 87 (~~ 374 ulekite. ...l cece ce., 83 ;- -' 85 Black, green and brown clay; a few crystals Black clay and Salt. 85 - 86 of salt and anhydrite. .__..-._._..}>. ._. 874% =.. 38 Salt and a little black clay and 86 -> 90 Salt and a little pale-blue clay _ ____________ 38 - - 43 Salt and a little ._.: 90 «:- 93 Salt; a little anhydrite; blue and brown clays. 48 - 44 Salt; gray and black clay; a little ulexite._._. 93 - 108 Salt and clays, changing from brown to gray. 44 - 46 Salt; a little ulexite; a very little gray clay ._ 108 - : 110 STRATIGRAPHY AND STRUCTURE TaBur 19.-Logs of wells drilled by Pacific Coast Boraz Co.-Continued A75 Description Depth (feet) Description Depth (feet) Well 3, Cottonball Basin, 2 miles northwest of Harmony Borax, SW}4 sec. 32, T. 28 N., R. 1 E.-Continued Salt, and a little gray, black, and brown clay. Hard salt and a little ulexite_____________-. Salt and some gray, brown, and black clay.. Salt; black clay; a little ulexite_____________ Hard salt and a little gray clay ___-_______. Salt; black clay; a little ulexite____._____.-_. Salt, and a little gray, brown, and black clay. Salt and black Salt and very little clay (black and gray) ___ A little brown clay, otherwise same_______ __ Black clay and salt, varying in proportions. Salt and very little black clay______________ Salt; a little brown clay; a few crystals NHleXibecc cen 22 leo neenee oen acer. asics Hard salt and a little ulexite_____________ _. Hard salt and a little black clay____________ Hard salt and a little brown clay___________ Light-Dlue clay : brown and Brown clay and salt, and a little ulexite_____ Brown'clay and Salt and a little gray clay, and considerable ulexite_ 2... 20. eee Canal ath nanan age Salt and a little gray and black clay_______. Softer material, loss Hard salt; a little black, brown, and gray clays 22 el oT L a La Ua a eine aa Salt; considerable brown clay; a little ulexite. Salt and a little brown Salt and brown and gray clays____________._ Salt and brown clay, and a little ulexite____. Brown clay, containing fine crystals of salt and anhydrite. Same material, except more anhydrite. Clay, with a little salt, anhydrite and ulexite. Brown clay and fine sand, containing a little salt and Same material (sand negligible) ___________. Brown and gray clay, and a little salt and anhydrite»... 2? c 02} cell ue ir e nae ences an on Bluish-gray clay and salt__________________ Salt, with a little anhydrite and brown and pray clay. 42 ll n .y ns Brown clay and ll" Hal-lg salt, and a little anhydrite and brown .si arn sees Pale-greenish-gray clay, and salt__________. Hard salt, with very little gray clay and see A seri cece ne aie e dail Hard salt, and a little gray clay____________ Salt, and gray and brown clay in thin strata A little gray clay, and small crystals of salt_. Small salt crystals, and a little gray and Drown'clay -..: litle. Fairly soft salt; gray and a little brown clay; occasionally a few tufts of ulexite____.____ Hard salt and a little gray clay___________. Softer material, sticky and probably wet... Salt and a little anhydrite________________._ Tough black clay, with very little salt_____. Salt and black and brown clay and a little ln ce CL crea- Same material, and sand decreasing in amount.... ~ s EdD ee oe n enews Salt and tough black clay..._...__...._._. Hard salt and a little gray-brown clay and met oe lin oal s oe enn ae o n e all a nie ae Very hard material (probably a salt stratum) - Salt crystals, with a little gray and brown clay and sand:. Harder material. No sand________________ Gray-brown clay, very sticky______________ 110 125 127 134 137 141 142 146 154 162 186 241 246 255 260 263 264 265 267 270 275 279 284 - 284% - 28814 - 290 - 292 - 208 - 301% - 320 ¢ 375 = 333 - 345 - 1 APSA Oded 4.4 44 A CPA 11.04 360 - 369 - 373 - 875 .- 376 385% 392 398 400 405 410 415 465 495 514 519 520 - ES A Led 525 - 538 - 540 - 545 - 5454 - 570. - 581 - 125 127 134 137 141 142 146 154 162 186 241 246 255 260 263 264 265 267 270 275 279 284 28414 288% 290 292 298 301% 320 323 333 345 360 369 378 375 376 385% 392 398 400 405 410 415 465 495 514 519 520 525 538 540 545 545% 570 581 592 Coarse salt, and large crystals of anhydrite; a little brown and gray clay and traces of calcium-carbonate cement-______________ Coarse salt, and some anhydrite, a little black and gray clay, and a few fragments thenardite.. .::: ser cle la clu clo Same material, with a little blue clay ___--_.- Same material, with a little brown clay ___. Blue-gray clay, about 50 percent; salt, anhy- drite, and thenardite in about equal pro- portions (see note on thenardite below) _ _ _ Blue and soft brown clays, otherwise same material-. - = Lelo ce nee ca ae ane na Brown clay; salt, anhydrite, and thenardite; a little ulexite and few borate fragments, apparently colemanite; some traces of calcium carbonate Tough blue clay and About 50 percent clay, blue, black and brown; crystals chiefly of thenardite, with a little salt and anhydrite. ____________-._ Same material; also a few nodules of clay, showing traces of cement____________--_.- Chiefly salt and clay; a little anhydrite and cl. n. Salt and clay, and notable sand; no other Crystals. .= ice ri keen. Gray, brown, and blue clay; very few crys- tals, of salt only .C... Tough, dry clay, as Brown clay and sand, with a little salt and anhydrite _. Brown clay, and a few crystals of salt and anhydrite; very little blue clay and sand _. Bluish-green clay, and sand and salt___-_-_--- Very little sand, otherwise same________-__. 90 percent clay, brown, blue, and gray; crystals of salt Salt stratum, Brown and gray clay, and a little salt____ ___ Same material, with some blue-green clay. __ Tough clays, gray, green and black; about 10 percent sand Tough light-blue Clays, brown, blue, black, and gray; about 50 percent salt. No record:... scc nk About 25 percent salt; remainder blue clay ._ About 10 percent salt; blue and black clay __ Very little salt, and no other crystals; brown clay, with sand increasing from 0 to 50 percent 's . su Cl caa ece aon ek -an Sand decreases from 50 to 5 Brown, gray, and blue clay, and a little salt and anhydrite Gray clay, and a little salt and anhydrite. About 10 percent salt, and very little anhydrite; remainder, gray, blue, and black clay.. .s ove cb uk o eod Gray, black, and brown clay, and a little Salto oo 2 e ore ea ee ae e aa onle ao allt ae Brown clay and a little sand_-__-___---__._. Brown clay, and sand increasing from trace £0 25 percent {2.3 2.0. uus Very tough blue clay and sand_____-_---_.. Tough brown clay, and a little sand ___--__. About 80 percent gray and brown clay, 15 percent coarse sand, 5 percent crystals consisting of salt and very little anhydrite. Dark-brown sandy clay and a little salt; a few traces 'of cal. Sandy gray and brown clay, otherwise same. 592 - 595 - 597 - 599 - 606 - 612 - 615 - 617. <- C bo Go we w I T16 .= 777 - 790 - 105 :- SIQ :: - §12 : - 815 - S19 .= 595 597 599 606 612 615 617 620 625 62814 630 635 640 646 665 670 671 677% 680% 681 690 695 704 706 720 72144 724 731 750 765 770 775 TTT 790 - 795 808 810 812 815 819 820 A76 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA TAaBug 19.-Logs of wells drilled by Pacific Coast Borax Co.-Continued Description Depth (feet) Description Depth (feet) Well 3, Cottonball Basin, 2 miles northwest of Harmony Borax, SW!4 sec. 32, T. 28 N., R. 1 E.-Continued Same material, except no ulexite..__._____. 820 - 845 Very hard, gray, black, and brown clay, with Same material, with a little black and blue a little salt and thenardite______________. 927 - 930 clay in addition. 845 - 850 DO.. icle ance ont 930 - 935 Sandy gray and brown'clay.._..._...._.... 850 - 865 Gray clay and considerable salt (soft) ___.. 935 - 945 Sandy gra g seh ue ns 865 - 880 Gray and brown clays, otherwise same_____. 945 - 951 Very tough gray and black clay, with a few Dark-brown sandy clay, with a little salt and crystals of salt and anhydrite___________. 880 - 890 anhydrite 22 ALU L ica v- a- ane 951 -- 959 Tough light-gray clay and salt____________. 890 - 896% Tough grayish-blue clay, with about 25 Tough light-blue clay and salt, and a little percent salt and a little 959 - 965 thenardite: s. 896% - 900 Gray clay; salt and considerable thenardite._. 965 - 974 Gray, black, and brown clay, and a little Light-gray clay and sand__________________ 974 - 975 galt and 900 - 904 Soft gray sandy clay; salt and thenardite__.. 975 - 984 Mostly brown clay, about 5 percent sand, Light-brown-gray clay, with some sand and and a little salt and thenardite__________. 904 - 909 about 10 percent salt and thenardite_____. 984 - 993 Very hard blue and black clay, with a little Clay, mostly gray and brown, with a little galt and 909 - 911 sand, thenardite, and about 25 percent Tough light-blue clay and salt; a little brown SATB 222 ec re ieee bein ns dana teen gie be a 993 - 996 clay and 911 - 915 Gray-brown clay and sand; about 10 percent Light-gray clay and salt, and a little salt; traces of thenardite____________.___ 996 - 998 thenardite and ulexite_ _ 915 - 916 Same material, but -_- 998 -1, 000 Same material, except no ulexite____._.___.. 916. - 920 Gray clay and some sand, about 10 percent Light-blue clay and salt; a little brown and salt, with a little anhydrite____________-. 1, 000 -1, 009% platk Clay c 920 - 925 Depth of 1, 00914 Dark-brown sandy clay and a little salt____. 925 - 927 PLEISTOCENE(?) AND RECENT(?) DEPOSITS SAND AND SILT IN THE PLAYA Sandy playa (and lake?) deposits crop out at the edge of the saltpan and foot of the gravel fans. The sand consists of very fine grained to medium-grained brown sand, most of which is rounded or subrounded quartz. Feldspar is abundant; there is some mica and hornblende. Depending on the source, there may be considerable amounts of volcanic glass or other volcanic rocks and of clastic grains of dolomite or limestone. A calichelike layer of salts occurs about a foot below the surface. : The sand is 3-10 feet thick and rests on gravel. Pre- sumably there is more sand below the bed of gravel, for the position is where the facies would intertongue. Originally, the sand must have graded into gravel on the fans; but the transition beds have been removed by erosion, and the sand now forms a low cuesta, 2-4 feet high, facing the gravel fans. Panward the sand grades into silt, which becomes increasingly clayey toward the center of the saltpan. Borings in the middle of the saltpan indicate that the sand deposit is 35-50 feet thick. There this deposit is overlain by the crust of salts form- ing the present saltpan ; it overlies a layer of rock salt a few feet thick. No fossils were found in the sand or silt. The sand is older than the sand dunes that can be equated with the earliest bow-and-arrow occupations in this area. It is older than the calichelike layer of salts contained in it, which is attributed to evaporation of ground water at the time of a Recent but pre-Christian era lake (p. A79). The sand is considerably dissected. It is crossed by numerous small washes draining from the gravel fans to the saltpan, and it is being overlapped by the No. 4 gravel that is being moved panward at present. NO. 8 GRAVEL The No. 3 gravel (pl. 2) differs from the No. 2 in several ways. The deposits contain less caliche and generally are less well indurated. The cobbles and peb- bles on the surface are firm and show little sign of dis- integrating; the rocks are not angular but are still round. Although not disintegrated, cobbles and peb- bles on some of these deposits have thin weathering rinds; other deposits lack even this. The gravels have a dark stain of desert varnish. Over a broad surface the stain may 'be darker than it is on the older gravels, because the No. 3 gravels are firm, whereas fanglom- erates of the Funeral Formation and No. 2 gravels are crumbly and the varnish there is partly destroyed. The No. 3 gravel is much better stratified in coarse- and fine-grained layers than is the No. 2 gravel. The range in grain size is substantially less and the propor- tion of gravel to sand is higher, although few boulders are more than a foot in diameter. Where there is a nearby source of large boulders in erosion remnants of the No. 2 gravel, some of these are reworked into the No. 3 gravel, but such reworked boulders are few. The surfaces on the No. 3 gravel are rough (fig. 53). The cobbles and small boulders are in ridges-natural STRATIGRAPHY AND STRUCTURE levees-1 or 2 fet high and as much as 10 feet wide. Washes between the levees are about the same width as the levees. The gravels also occur in small fanlike mounds that choke washes and disrupt the drainage. Nowhere is there desert pavement on these deposits like that on the No. 2 and older gravel. The range in size of the gravels on the surface of the No. 3 is the same as within the deposit. Three kinds of surfaces have formed on the No. 3 gravel. Surfaces that have not been subject to flooding or washing are only a little less smooth than the desert pavements on the adjacent older gravels. Such surfaces are rough only because the ill-sorted small boulders, cobbles, and pebbles stand at different heights and are distributed irregularly on the surface. The stones are darkly stained with desert varnish. Surfaces that have been subject to flooding, but not recently, are composed of levees of small boulders along the sides of washes floored with pebbles, and both the levees and washes are darkly stained with desert var- nish (fig. 53). Desert varnish is thicker and darker on stones on these first two types of surfaces than on any other gravel deposits in this part of Death Valley. The third type of surface is like the second, except for recent washing. -On these surfaces the levees are stained with desert varnish, but the pebble floor of the wash is not. This third kind of surface grades into that of the No. 4 gravel. The surfaces on the No. 3 gravel similarly grade into those that have formed on the No. 2 gravel. Where surfaces on the No. 2 have been overriden by flash floods, a layer of firm cobbles and pebbles overlies the pavement of partly disintegrated slabs and flakes. In these places the firm cobbles and pebbles form low ridges on the pavement, and the old desert pavement forms the beds of the little washes between the natural levees. Other surfaces on the No. 2 are dissected by shallow washes which have become mantled with firm cobbles and pebbles, leaving narrow interstream areas capped with the old desert pavement. A third kind of grada- tion is where the No. 3 gravel has been derived by erosion of old disintegrated gravel; depending upon how far such gravel was transported, there may be enough angu- lar stones to form a surface like that on an older deposit. Such surfaces, however, lack the silt layer that is characteristic of older desert pavement. Much of the ground shown as No. 3 gravel actually is only a thin veneer of this gravel on an eroded surface of the No. 2. The No. 3 gravel is neither as thick nor as extensive as the No. 2. In general, the surface of the No. 3 gravel is lower than that of the No. 2 and generally less than 10 feet above the No. 4. But the No. 3 gravel overlaps the ATT Argillite (left) is smoothly FicurB 54.-Wind-faceted cobbles. Both speci- faceted ; limestone (right) has rillen on the facets. mens oriented as in the field. lower edges of the No. 2, and at such places has accu- mulated in small fans on top of it. Conversely, the No. 3 gravel is overlapped by the No. 4 (figs. 55, 64). The Funeral Formation and the No. 2 gravel general- ly are without vegetation, but the No. 3 gravel generally has a sparse growth of shrubs along the shallow washes bet ween the natural levees of cobbles and small boulders. This reflects the difference in permeability and runoff on the two surfaces. Runoff is greater on smooth desert pavement than it is on the rougher surfaces of the No. 3 gravel, and the ground is accordingly more xeric and less suitable for plant growth (see Hunt, 1965). Pebbles and cobbles on the surface of the No. 3 gravel are wind faceted (fig. 54) at several localities, for ex- ample, along the south side of the Hanaupah Canyon fan 1-1% miles due west of Eagle Borax, on a bench at the mouth of the wash at the north end of the Artists Drive fault blocks (NEV, NEY see. 15, T. 26 N., R. 1 E.), and on the Salt Creek Hills. In the latter area some stone artifacts are clearly etched by sandblasting. Glass bottles that have been exposed are frosted and etched. The wind-facted pebbles may have been de- veloping their facets over a long period of time, but certainly some of the shaping is Recent. At several places the No. 3 gravel has been displaced by small faults. At the Hanaupah escarpment, 1 mile west of Shortys Well, the No. 3 gravel is displaced 6 feet along a fault that displaces the No. 2 gravel 75 feet (fig. 48). At most places, though, the No. 3 gravel overlaps faults without being displaced. Good examples are be- side the highway 2 miles south of Bennetts Well (fig. 55) and at the south edge of the Trail Canyon fan 11 miles southwest of the junction of the Trail Canyon road and West Side highway. The No. 3 gravel is old enough to have been eroded into low benches and to have developed extensive desert varnish on the surface. Numerous archeologic sites on the gravel indicate that the bow-and-arrow and pottery occupations at those places are later than the No. 3 gravel. - Further, the No. 3 gravel every where is darkly stained with desert varnish, but archeologic sites of the bow-and-arrow occupations are not. There ATS FicurE 55.-No. 2 gravel (foreground) displaced 6 feet by a fault that is overlapped and buried by No. 3 gravel (distance). Locality is by West Side highway 2 miles south of Bennetts Well. View north. is little reason to doubt that the gravel everywhere is older than these archeologic sites and antedates the Christian era. Probably the No. 3 gravel includes de- posits that are early Recent in age and other deposits as old as late Pleistocene. DEPOSITS OF TRAVERTINE AND CALICHE CEMENT IN GRAVEL Travertine has been deposited in mounds at and near each of the large springs issuing along faults west of the Funeral Mountains, and a small mound has been built on the upper part of the Trail Canyon fan. The de- posits are nearly pure calcium carbonate. The largest deposit is at Nevares Spring at the foot of the mountains 2 miles east of Park Village. Travertine has been deposited at Travertine and Texas Springs, and between them are some mounds of travertine that have become isolated by erosion. - these deposits drapes over the side of Furnace Creek Wash and extends to the bed of the wash (fig. 56), Fisurs §56.-Travertine deposit overlapping the bank of Furnace Creek Wash half a mile above the mouth of the wash. The old spring, now dry, that deposited the travertine was at the high mass of travertine that can be seen beyond the telephone line. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA clearly dating the travertine as younger than this part of the gorge of Furnace Creek Wash. On the gravel fan at Trail Canyon, a mile below the mouth of the canyon, is a mound of travertine 5 feet high and 30-50 feet in diameter. Another travertine deposit on the west side of Death Valley is at the south base of the hill of basalt south of the mouth of Black- water Wash,. The deposit is at an altitude of 200 feet in a cove at the toe of a field of basalt boulders over- lying tuff. The travertine probably was derived from the carbonate caliche in the basaltic boulders up the hill- side and probably dates from a time when there was a spring here. Travertine obviously is being deposited at Nevares, Texas, Travertine, and similar springs at present, yet much, probably most, of the travertine is an old deposit, probably dating back to late Pleistocene time. Some of the deposits are at locations where springs have dried up. Other deposits are old enough to have been isolated by erosion from the spring areas. Projectile points of types characteristic of the early occupations have been found on the surface of some mounds. A few fossils were found, but they are not meaning- ful. At Nevares Spring, 4 feet below the surface, 4 teeth were found and identified as mountain sheep (Ovis canadenis Shaw) by G. E. Lewis, of the U.S. Geological Survey, and C. B. Schultz and L. G. Tanner, of the University of Nebraska State Museum. Some mollusk shells from the same layers of travertine at Nevares Spring (U.S.G.S. Cenozoic loc. 21675) were identified by D. W. Taylor, of the U.S. Geological Sur- vey as Hydrobiidae indeterminate, a fresh-water snail. Some shells from travertine at Triangle Springs (U.S8.G.S. Cenozoic loc. 21575) on the northwest side of Mesquite Flat also were identified by Taylor as follows: Pisidium sp., a fresh-water clam Hydrobiidae, 2 indeterminate species probably representing 2 genera of fresh-water snails Physa, a fresh-water snail Vertigo, a land snail of. Succinea, a land snail Taylor (written commun., 1961) offers the following ecologic interpretation of these species : The two terrestrial species are inhabitants of moist situations, such as vegetation along streams, beside ponds, or in marshy places. The fresh-water species do not inhabit wide ranges of salinity; the water certainly was fresh rather than brackish. The water temperatures may have been warm, but not hot-possibly as high as 80° F. % The living molluscan fauna of the Death Valley area is es- sentially unknown. For this reason the significance of the mollusks cannot be evaluated satisfactorily. Perhaps all the species represented by the fossils are living; perhaps only some. STRATIGRAPHY AND STRUCTURE Fresh-water snails in another collection from the irri- gation ditch at Furnace Creek Ranch were identified by Taylor as: Helisoma duryi seminole Pilsbry, a Floridian species, prob- ably introduced through aquaria Physa The calcium carbonate caliche that cements layers of gravel on the fans is well developed where the gravels overlap the fine-grained Tertiary playa deposits, places favoring perched ground water. Such cemented ledges are extensive where the gravels overlap the Tertiary rocks below Nevares Spring and along the west edge of the Texas Spring syncline, where ground water comes to the surface. However, for reasons that are not ob- vious, the caliche also is well developed on the fans of Galena and Six Spring Canyons. Although most of the caliche is calcium carbonate, there is considerable calcium sulfate caliche locally, es- pecially along the foot of the Black Mountains, as had been noted in the description of the Funeral Formation on Artists Drive (p. A64). Certainly the greater part, and perhaps all, of the caliche in these gravel deposits has been deposited by ground water, or more likely, by water in the capillary fringe above the water table. The best evidence for this is the commion occurrence of well- developed caliche where there is a perched ephermeral water table. That much of the caliche is old, perhaps late Pleisto- cene in age, is indicated by the occurrence of earliest archeological sites (Death Valley I and Death Valley II; Hunt A. P., 1960) at shelters or ledges formed by the caliche. Trace elements in the travertine are given in table 20. They are much the same as in the calcite veins cut- ting the Funeral Formation. 20.-Trace elements in spring-deposited travertine and in calcite vein in Funeral Formation [Spectrographic analyses by E. F. Cooley, U.S. Geol. Survey, values in parts per million, except Mg, which is given in percent] B | Ba | Be | Bi | Cd | Co | Cr | Cu | Ga | Ge Travertine !...... <10 | 150 | <1 10 50 | :uo Buoje soSpiy 0008 uofuey AajjeA yjeaq Suoje mww0_m\7:/I-wm uuuuuuuu 1000'Ot > 1000'OT \ 10008 10008 13A37 ¥3S 13A37 ¥3S uofuey Oyog,_. ~ = uepyeasqsoeumg V useg jjequonoo ___ janes ue] _ "--- os-" ipo Jo us i.. oo c- oe alls e Bon Lenco will rons aii oir o ae o nthe ian Sac h c 1 0 oui ME ene Free de as sour noe ieee ener fae youeq Tg 10008 x /:o>:mo oyo3 Suoje saSpiy 10006 3 M STRATIGRAPHY AND STRUCTURE junction of the road to the Salt Pools. No doubt there have been others, but only 1 percent or so of this 45- mile stretch of highway has been washed by destruc- tive floods in the last 20 years. The original highway along the east side of Death Valley was along the foot of the gravel fans; it was last bladed when the present highway was paved about 20 years ago. A survey was made of damage along the stretches of this old bladed road where it has not been disturbed by later construction; the shoulder on the uphill side of the road averages about 6 inches high and perhaps a foot wide. Floods across this road in the last 20 years have destroyed about 20 percent of this little feature, as indicated in table 22. TABLE 22.-Erosion, in 20 years, of road shoulder 6 inches high along old bladed road from Beatty Junction south along the foot of the gravel fans Road shoulder $ Length destroyed Location of traverses along old road of road Length | Percent 1 | South from BM-233, 1 mile west of Beatty Junction: BM -233 to BM -241____.___._.._ miles.. BM -241 to BM -245.. BM -245 to BM -250.. oud. su bnt bnt bet ut but joi jet BM -249 to BM -255.. BM -255 to BM do.... BM -254 to BM -255....__.._____. do..... Pobal OF -.. .!! uue cen 7 2 | 14 mile north of Golden Canyon, south to Desolation Canyon. fee 12, 500 3, 400 27 3 | Near Artists Drive exit, south nearly to the highway across the valley _____________ do. 13, 000 2, 000 15 4 | Near highway across Death Valley, south to. .... 2. .u... LL eens en miles 10 3 30 & | Around foot of second fan south of Bad- WAEOEL 2. 022.2 pL oo dav anon feet .. 7, 500 2, 200 20 Fifteen miles of the traverses indicated in table 22 are on the fans between Badwater and Golden Canyon. These fans are composed of fine-grained sediments that are impermeable and favor runoff-far more so than the permeable gravel fans. In the last 25 years, floods on this impermeable ground have destroyed about 20 per- cent of a ridge of loose earth 6 inches high and 1 foot wide. The runoff, of course, has been channeled in washes, and in some washes there have been repeated floods. Nevertheless, 80 percent of the little ridge still stands. When the new road was built, 15 flood-control ditches totaling about 5 miles in length were constructed in the northern part of the valley. The ditches were con- structed at the most exposed locations. They extend diagonally across washes and are oriented about 45° to the highway. Originally the ditches were about 5 feet wide and had a maximum depth of about a foot. An earth embankment about as wide as the ditch and about a foot high was constructed along the lower side of each ditch. Floods in these washes in about 25 years have A95 TABLE 23.-HErosion of flood-control embankments in 25 years Approximate Locality length of - |Destruction embankment | (percent) (feet) 1 | 2.5 miles northwest of Beatty Junction; embankment oriented slightly west of north __________. 2, 500 25 2 | Same location; embankment oriented slightly north of east.... 4, 000 30 3 | 0.9 mile southeast of Beatty JURCHON. . en e ece sansa nana am 2, 500 30 4 | 1.5 miles southeast of Beatty 1, 200 10 5 | 1.8 miles southeast of Beatty Junction; embankment oriented slightly west of north 2, 000 25 6 | Same location; embankment oriented about east___________--- 2, 000 10 7 | 2.3 miles southeast of Beatty Junction... suse 2, 200 30 8 | 3.3 miles southeast of Beatty 2, 000 15 9 | 3.6 miles southeast of Beatty TUNCHON.... .= -s c c erk 1, 000 20 10 | 4.6 miles southeast of Beatty Junction; embankment oriented northeast..-.....~..2cleelcuuene~ 2, 000 40 11 | Same location; embankment oriented southeast__________---- 1, 000 25 12 | East side of highway opposite exit from Mustard 1, 200 30 13 | 1.3 miles north of Furnace Creek 800 30 14 | 1 mile north of Furnace Creek RANCH 1, 000 30 15 | 0.3 mile northeast of Furnace Creek 2, 000 30 destroyed about 25 percent of the embankments (table 23). Even in washes where runoff is concentrated, after 25 years of floods about 75 percent of an earth ridge 1 foot high still stands. On the flood plain of the saltpan at the Devils Speed- way at the foot of Trail Canyon fan, some racetrack runways were scraped about 25 years ago. The area is flooded seasonally. A circular track half a mile in diameter, with a smaller one inside, was scraped north of the road across the valley ; another nearly a mile long and more oval, was scraped south of the highway. At one curve an embankment about a foot high was built, but elsewhere the scraped track was bordered by only a low ridge of earth about 6 inches high. After 25 years, enough of the ridges still remain to outline plainly the position of the old tracks; there has not been enough silting or erosion on this part of the flood plain to destroy these minor artificial features. DAMAGE TO TRAILS ABOUT 50 YEARS OLD Old trails cross the fans diagonally or follow the contour and lead from one spring to another and to routes into and away from the valley. These trails are the original freeways, perhaps originally made by A96 Pleistocene animals, then used by the Indians who came into Death Valley, and finally by the pioneers. The trails, though, have been little used in the last half century; they were abandoned when vehicular traffic became heavy enough to require roads other than those that could be followed on foot or horseback. The trails are preserved because there has been no livestock in the valley. That the trails were used by the Indians is indicated by the concentrations of stone artifacts and other ar- cheological signs along them. 'That the pioneers and early prospectors used the trails is indicated by the common occurrence of pre-1900 relics along the trails. That the trails have been little used during the last 50 years is indicated by the scarcity of litter younger than about 1900 and by the occurrence of narrow coyote trails meandering within the wider, older trails Results of some surveys along stretches of the old trails are given in table 24. In general, the old trails are for the most part intact where they cross high benches on the No. 2 gravel, sug- gesting that in the present regimen erosion of these benches must proceed by retreat of the sides rather than by lowering of their tops. Where the old trails cross No. 3 gravel, 10-20 percent of the alinement may be destroyed, and the destroyed stretches invariably are in the swales where runoff is concentrated. Part of this runoff originates on the No. 3 gravel, but most of it represents overflow from nearby washes. Even where the trails cross washes with No. 4 gravel, as much as 25 percent of the alinement may be pre- served. Destruction is more complete where main washes are crossed on the upper parts of the fans rather than on the lower. This may be due to the runoff being concentrated in a few channels on the upper parts of the fans, or it may be due to greater total runoff, or perhaps to both. Reference has been made to the steps (terracettes, fig. 51) and related features resulting from mass wasting on the gravel fans, especially on the No. 2 gravel. (See p. A68; see also Hunt and Washburn, in Hunt and others, 1965.) The trails cross such features without showing signs of creep downhill. DAMAGE TO PREHISTORIC ARCKHEOLOGICAL FEATURES More than a dozen rock alinements dating from the Death Valley III occupation are preserved at various locations on the No. 2 gravel around Death Valley (Hunt, A. P., 1960). Some of these alinements were made by laying pebbles or small cobbles in a row ; others were made by scraping the gravel into a ridge 2-4 inches high. These slight features still stand despite GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA 24.-Erosion along old trails in the last half century. yoga "mls" Location of traverses along old trails (hm ages <> Feet Percent 1 | 1% miles across Artists Drive fan, across sees. 15 and 22, T.20 N:; R. 1 ', 800 | 4, 800 62 2 | West of road 2 miles south of Bennetts Well____________._ 1, 250 800 64 3 | 3 miles across northeast corner of Cottonball Basin. Be- gin at north end at BM -245, trail- Across sand facies of car- bonate zone._...__...__.. 3, 900 975 1 25 To Natl. Park Service Monument, 2934, 8296, on gravel fan...... 2, 000 2, 000 100 On fan southward to old e 2, 000 675 30 Southward from old road across saltpan-______._. 3, 800 800 21 To BM -255 along foot of gravel fan._...:.__._ 3, 300 3, 000 90 4 | Near Salt Springs, south to near Cow Creek__________. 10, 000 | 2,000 20 5 | 3.7 miles, from Nevares Spring to Texas Spring.... 1, 300 0 | None 1, 050 1, 050 100 450 0 | None 300 300 100 550 0 | None 4, 525 750 16 2, 100 850 40 900 900 100 550 50 10 1, 250 625 50 1, 200 200 15 350 175 50 2, 000 1, 800 90 925 90 10 750 750 100 6 | %4 mile, from Furnace Creek Ranch to Nevares Spring. Begin at road into East Coleman Hills____________._ 2, 600 750 29 7 | North from Nevares Spring to Echo Mountain wash. Be- gin 1} miles north of Ne- vares Spring......-.-l...l.- 7, 400 1, 400 15 4, 000 0 | None 1, 400 975 70 Total or average...... 67, 650 | 25,715 38 ' Half by salt heave and about half by erosion. approximately 1,000 years' exposure to sheetfloods on the gravel. Perhaps there were other alinements that have been destroyed by sheetfloods, but probably no more than a few judging by the preservation of trails on the No. 2 gravel. In addition to the alinements, there are approximate- ly 1,500 rock circles. These are on the No. 3 as well as on the No. 2 gravel. They are not well dated ; some are historic. Others are prehistoric Death Valley IV, and some probably date from Death Valley III occupation. Most of these rock circles consist of a single layer of cobbles arranged in a circle 5-7 feet in diameter. Some STRATIGRAPHY AND STRUCTURE circles located along the rims of washes have been part- ly destroyed by undercutting of the rim, but circles back from the rim show very little sign of washing. DAMAGE TO RECENT FAULT SCARP ALONG FOOT OF BLACK MOUNTAINS The Recent fault that extends from the mouth of Furnace Creek 30 miles south to Mormon Point (p. A 100) forms a discontinuous escarpment 5-10 feet high. The faulting is believed to have occurred about 2,000 years ago. Since that time about 90 percent of the escarpment has been destroyed, partly by dissection of the upthrown block and partly by burial under younger alluvial-fan deposits (fig. 72). WEATHERING, EROSION, AND SEDIMENTATION ON QUATERNARY DEPOSITS In the present climatic regimen disintegration of stones is slow enough not to be noticeable in the No. 3 or No. 4 gravels, yet in the No. 2 and older gravel de- posits, disintegration is continuing, as indicated by the accumulation of fine debris around the foot of boulders (fig. 49). This difference between the No. 2 and the younger. gravels could be attributed to difference in length of time that the gravels have been exposed at the surface, but more likely the difference is due chiefly to some changes in the processes causing disintegra- tion-changes attributable to the climatic changes that occurred during late Pleistocene time. Erosion and sedimentation under the present climate are slow too. Areas on the saltpan that are subject to flooding are restricted to the flood-plain areas which constitute about 30 percent of the valley floor. The salt crusts on the other 70 percent were deposited about 2,000 years ago, and the only part of this crust that has been flooded is the smooth silty rock salt, constituting about 30 percent of the crust. The smooth salt has been flooded often enough in 2,000 years to deposit 1-6 inches of silt on the salt. - Only fine sand and silt is transported onto the flat valley floor ; gravel is deposited at the foot of the fans. The only exception to this is provided by a few cobbles of light highly scoriaceous lava washed onto the salt flat at the foot of Furnace Creek fan. The No. 4 gravel, covering about a third of the gravel fans, represents the part of the fans that is subject to much washing at present. - The No. 3 and older gravels, darkly stained with desert varnish, have not been . washed sufficiently in 2,000 years to destroy that stain, which is pre-Death Valley III occupation (p. A91). Erosion and sedimentation on the gravel fans in 2,000 years, therefore, have been restricted to about a third the area of the fans. The volume of the No. 4 gravel is small compared to the older gravel formations and seems to be little, if any, A97 more than the volume of the washes and channels that are eroded into the older gravels. Apparently not much gravel has been brought from the mountains to the gravel fans in 2,000 years; the No. 4 gravel seems to be derived chiefly from erosion of the older gravel formations. Further evidence that little gravel is being trans- ported from the mountains under the present climate is found where the No. 2 or No. 3 gravels overlap the foot of the mountains. Alluvial fans of No. 4 gravel have been built on the older gravels only at the mouths of large washes. Elsewhere, little new material has been moved from the mountainsides onto the surfaces of the old gravels. The deposits of the last 2,000 years-the No. 4 gravel and floodplain deposits-if spread over the whole valley, would average considerably less than a foot thick, and much, perhaps most, of this is simply reworked older valley fill. Only a fraction can represent new sediment brought into the valley from the mountains. Exact figures cannot be had, but no matter what figure is as- sumed within the known limits, clearly the thick Quater- nary fill in Death Valley could not have been deposited if the rate of erosion in the mountains had always been as slow as it has been during the last 2,000 years. The history of erosion and sedimentation in Death Valley evidently is one of changing rates, presumably due to changing processes. Huntington (1907) offered the hypothesis that in arid regions the pluvial periods accelerate weathering and growth of vegetation. Dur- ing such periods, waste is stored in the mountains. Ac- cording to him, the transition to an ensuing arid period is the time when most of the waste is transported to the alluvial fans; when the supply of waste becomes ex- hausted, there is little new material brought from the mountains and the older fill deposits become dissected. The evidence in Death Valley fits well with Hunting- ton's hypothesis. STRUCTURAL GEOLOGY By CnartEs B. HuxT and Don R. MaBEYy The structural geology of the Great Basin, of which Death Valley is a part, has been a century-long subject of discussions and differences of opinion. One of the principal conclusions arrived at from our studies of the structural geology in Death Valley is that the discus- sions and differences of opinion will continue for a long time to come. The mountains bordering Death Valley are uplifted fault blocks of the general kind first recognized in the Great Basin by G. K. Gilbert (1875), and later, with modifications, by King (1878) and Dutton (1880). A98 (For a review of early theories about Great Basin struc- ture, see Davis, 1926, and Nolan, 1943.) But the moun- tains have had a complex history of early deformation and erosion that is not reflected in the shapes of the uplifted fault blocks, a complexity first clearly demon- strated in the Great Basin by Louderback (1904), al- though alluded to by the earlier investigators. Few to- day will seriously entertain the theory (Keyes, 1909) that the basins like Death Valley are chiefly erosional in origin, but many will ponder the degree to which the structural framework involves folding and thrust fault- ing as well as block faulting, an extreme view of which, advanced by Spurr (1901), discounts block faulting and attributes the basins and ranges to an Appalachian Mountain type structure in a desert climate. Too, our lack of knowledge allows for differences of opinion about the significance of the granitic intrusions and vul- canism to the deformation ; indeed, this subject has re- ceived little attention. Although Spurr's main thesis needs to be greatly modified, we think he was more right than wrong in his view that deformation has gone on "steadily though spasmodically from the close of the Mesozoic to the present." In the course of that long period of time, usually taken as 60 million years, the way in which the GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA crust has yielded to stress has changed, and the earlier structures therefore are obscured by thé later ones. The record admittedly is not complete enough to demonstrate continuity of the deformation. Probably the most basic uncertainty to understanding the structural framework of Death Valley and the rest of the Great Basin is uncertainty as to whether this part of the crust has been shortened by compression or distended by tension. The evidence is conflicting- in Death Valley and elsewhere in the Great Basin. Whatever the origin and complete sequence of struc- tural events have been, the result is a complex of strain effects superimposed on one another. We attempt to unravel these by examining the younger first, and by eliminating their effects we attempt to restore seriatim earlier structures to the way they first appeared; the effort is only partly successful, for reasons that will become apparent as we progress. STRUCTURAL SETTING OF DEATH VALLEY Death Valley is about centered in an area that is a subsection consisting of the southernmost tenth of the Great Basin (fig. 68). The Death Valley subsection is characterized by block mountains that are of Precam- YA.» > 38 & 7V_\<>L 4 4 # I > Ye iF 8 v - “FL n C f y Tio > & yas % e a a c Hi aie Mog NE s Ap Te < a ALV|C A a > ¥ 3 H \/,< Aal y 4295s mE»: Nav < sL, >1 Jon 19. « xb s- iy a "s Block 4 ~ faulted} " V Tertiary. c ~, volcanic , ". "rock w is ? v - r s/ y PS2 A - a fa mamte Tai a f K a C2 a. yi2 41574 A 3 /m t CoA Pa aL ; % a 74Av2 2 El e a. as - me sg ik. C& \\‘ 3 > T a- % Feet o_ 1 > xz af 1 2 fas) S ly N -> w § 5 ARe 1h =z ihe C X eS --- w £- T 3 o 2. vp = & Co C \_/—— a #8 ye a % o p & o $ #I // /_ $+ ot FicurE 68.-Map showing the Death Valley subsection of the Great Basin. TKs, granite at Skidoo ; TKh, granite at Hanaupah Canyon. in black. 50 75 MILES 1 1 Mesozoic and Tertiary granitic intrusions shown /A STRATIGRAPHY AND STRUCTURE Death" Nt. Valley * FiGurE 69.-Map showing seismic epicenters in southwestern United States. From Woollard, 1958. brian and Paleozoic formations intruded by granitic rocks and locally capped by Tertiary volcanic rocks. To the north, the next subsection of the Great Basin is characterized by block mountains that are almost entirely of Tertiary volcanic rocks. West of the Death Valley subsection is the Sierra Nevada batholith ; to the east, along the Colorado River, is a small area that is largely Precambrian granite and assigned to the Mexi- can Highland ; and beyond that is the Colorado Plateau. Southward the Death Valley subsection ends at the Mojave Desert (Hewett, 1955), a subsection of the Sono- ran Desert. Death Valley extends along the eastern edge of a cluster of granitic intrusions that are satellites of the Sierra Nevada batholith (fig. 68) ; it is at the eastern edge of the seismically active areas that extend westward to the coast (fig. 69). Along this border of the granitic intrusions and seismically active areas is a series of curi- ous overthrust faults, first recognized and described by Noble (1941). These faults are curious because younger rocks have been thrust westward over older ones. Be- cause the horizontal movement is measurable in miles, we follow Noble in referring to the faults as thrust faults, although the displacement on them in fact is that of a normal fault (Longwell, 1945). Noble, and later Curry (1954), also recognized that the thrust faults have had a complex history including later folding of the faults and later block faulting. Also, Noble recognized that granitic intrusions had spread laterally at some thrust faults as if controlled by them. The thrust fault first described by Noble was named the Amargosa thrust. Because this type of thrust fault- ing now is recognized widely in the Death Valley sub- section (Longwell, 1945; Mason, 1948; Kupfer, 1960), we extend the term and refer to this system of faults as A99 the Amargosa thrust system, including the faults that branch upward from the main thrust. About 60 miles east of Death Valley, and near the east- ern edge of the Death Valley subsection, is a belt of con- ventional overthrusts along which the thrusting has been directed eastward-opposite to that of the Amargosa thrust system. At these overthrust faults, Paleozoic for- mations have been thrust eastward onto Mesozoic ones and the faulting has been interpreted as Late Jurassic, Cretaceous, or early Tertiary (Longwell, 1926, 1928, 1949; Hewett, 1931, 1956). East of this belt of conventional thrust faults is an area exposing extensive Precambrian granite-part of the Mexican Highland-and east of that is the Colorado Plateau. The dominant structural and topographic grain of the Death Valley subsection is northerly and northwest- erly. The structures however rise southward from un- der the Tertiary volcanics in the subsection to the north. Within the Death Valley subsection the southward rise is further reflected by the dominance of Paleozoic forma- tions across the northern part of the subsection and the dominance of Precambrian formations across the south- ern part. Structurally, the Mojave Desert appears to be as high or higher than the south edge of the Death Valley subsection. Bouguer gravity-anomaly values in the Death Valley area are irregular but high compared to those under the Sierra Nevada to the west and under the Great Basin to the northeast (fig. 70). The gravity values suggest that the crust is relatively thin under the central part of the Death Valley subsection, and that it thickens westward and northeastward. ks -200 Death £ Valley "00 \& L| \ 0 » \ 3 0 ~ [00 K2. 90 FicUrB 70.-Bouguer gravity-anomaly map of southwestern United States. Contour interval, 100 milligals. Based on G. P. Woollard (unpublished data) and Mabey (1960). A100 The major structural features of Death Valley and the mountains adjoining it are illustrated on plate 3. RECENT AND LATE PLEISTOCENE STRUCTURAL GEOLOGY % STRUCTURAL FEATURES OF THE SALTPAN AND GRAVEL FANS Recent and late Pleistocene structural features of the saltpan and gravel fans include (1) Recent eastward tilting of the saltpan and associated faulting; (2) five small Recent anticlines and five small Recent faults af- fecting the saltpan ; (3) numerous faults including some graben structures and small folds of late Pleistocene age on the gravel fans (fig. 71). RECENT TILTING OF THE SALTPAN The saltpan is the product of a Recent lake about 30 feet deep, and dated archeologically about 2,000 years ago (p. A79). The eastern shoreline of this Recent lake is 20 feet lower than the western shoreline. About half the tilting may be accounted for by a 10-foot-high Re- cent fault scarp along the foot of the Black Mountains (fig. 72). The eastward tilting of the saltpan is reflected also in differences in the drainage along the two sides. Along the east side of Badwater Basin the flood plain is smooth and is being aggraded; but along the west side the Amargosa River and its tributaries are entrenched in deep channels, and in places the flood plain is being dissected. That the tilting occurred suddenly about 2,000 years ago rather than progressing gradually during that time is indicated by the arrangement of the concentric rings of salt in the saltpan, for they are crowded against the east side. That the fault scarp developed at the time of tilting is probable. The scarp is well enough pre- served to leave no doubt that it is Recent, yet it has been partly destroyed by erosion and partly buried by younger gravel. That it is prehistoric is shown by the fact that Indians constructed mesquite storage pits in the colluvium that overlaps the scarp (figs. 72, 73). The tilting, together with the faulting along the side towards which the tilting occurred, duplicates in many details the features that accompanied the earthquake at Hebgen Lake in the West Yellowstone area in 1959 (U.S. Geol. Survey, 1959), and very likely the tilting and faulting occurred equally suddenly. RECENT ANTICLINES AND FAULTS AFFECTING THE SALTPAN Other recognizable structures that affect the salt crust and that evidently are no more than 2,000 years old in- clude 5 anticlines and 5 small faults. All these repre- sent renewed movement along preexisting structures. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA EXPLANATION a Area of saltpan - -manvd AST IVA aL. Direction of tilt of mountain blocks U D Fault S & U, upthro wn side Ta D, downthrown side 4:74:00 9 X6 1 Anticline a, Artists Drive s, Salt Creek Hills 4—*— Syncline t, Texas Spring Owlshead Mountains 10 0 10 20 MILES CONTOUR INTERVAL 2000 FEET DATUM IS MEAN SEA LEVEL FIGURE 71.-Principal Quaternary structural features in Death Valley. The Death Valley fault zone is cut off at the north by the Furnace Creek fault zone and at the south by the Confidence Hills fault zone. The far FIGURE 72.-Recent fault scarp at foot of Black Mountains. and of the escarpment is buried by debris washed from large can- yous and is dissected by small washes from small gullies on the right. View is north on south side of Furnace Creek fan. Two of the anticlines are in the southern part of the Badwater Basin (pl. 3), and both trend northwestward from anticlines in the older rocks (Precambrian), marked by turtleback ridges (Curry, 1954), in the Black STRATIGRAPHY AND STRUCTURE N S. EXPLANATION l C sins:. ". \20 e Indian mesquite pits C est (rock circles) T 3, G -~. Bluffs \ \////// é Rock trap \_h///////7 J \in \ -*- & 7/\ F3 Fault z 1 ¢ -& jit] = R.., % gin \//// Cs \% /// Bluffs 2 13 \3, ww Lint - wuss t ~'Ghannel 5 ft deep \ \\\\m,\|wm|(u/// Escarpment 5 ft high \\:;: .. \ e\ 2 t o o oké/O > \:2 ia" zw" X 2p ult A6 ""ll «ojo mn s (" % J ~ k Q\\c\/mm\\\ N-" Bluffs E' \ ss (UW o, \ Z/] \ ow \ 100 0 100 200 FEET \\ (Cs HR (ede PL PCO 222201 FicuUrE 73.-Map of Indian sites along the escarpment of a Recent fault at the foot of the Black Mountains 3 miles south of Furnace Creek Wash (modified from A. P. Hunt, 1960). The fault and escarpment are older than the Indian mesquite storage pit at D, which is built in colluvium overlapping the scarp. Mountains. They are expressed by sweeping curves in the drainage that lies between the foot of the mountains and the edge of the rock salt deposited by the Recent lake in the interior of the saltpan (fig. 74). The anti- clines are manifested by northwest-plunging noses in the gravity contours (pl. 3); this indicates that the anticlines are underlain by highs on the surface of the bedrock, which probably is Precambrian. A third anticline extends across the saltpan where the highway crosses it at the Devils Golf Course, west of Artists Drive. The trend of this anticline and the location of its highest part are uncertain. Nearby fault blocks of the Funeral Formation along the east edge of the saltpan trend southwest, but the anticlinal axis may or may not coincide with them. Because of Recent uplift on this fold, drainage that formerly was south to Badwater Basin now is ponded in Middle A101 Edge of rock salt PME Mics Mountains Projection of axis of C o p per Canyon turtle- back Projection of axis of turtleback at Mormon Point 1 0 1 2 MILES L 1 1 1 1 1 1 FIGURE 74.-Map showing drainage in the Death Valley saltpan deflected at the projected axes of turtlebacks in the Black Mountains. Basin north of the fold. Leveling along the channel of Salt Creek, which extends from Middle Basin to A102 Badwater Basin, indicates that the stream course has been arched 18 inches and that a pond that deep must form in Middle Basin before it will overflow again into Badwater Basin. There was no such overflow during the 6 years 1955-61. Litter along the channel is mostly pre-1900 type, that is, planks with square nails and old bottles with hand-finished necks. There is almost no modern litter; thus, it would appear that there has been no flood of consequence along this stretch of channel during the last half century. The buried anticline separating Badwater Basin from Middle Basin is marked by a gravity high and is confirmed 'by drilling that encountered the Funeral Formation 120 feet below the surface of the saltpan. The drill hole is near the middle of the saltpan beside the road across it; a log of the hole is given in table GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA 19, well 2. The drill reached a depth of about 500 feet, still in the Funeral Formation so far as known. An- other hole about / miles southeast, toward Badwater, was drilled to a depth of 1,000 feet, and did not reach the Funeral Formation so far as can be determined from the log. It may be inferred that the Pleistocene deposits thicken southward from 120 feet above the buried anticline to more than 1,000 feet west of Badwater, A fourth anticline is in Cottonball Basin. It lies along the projected position of the faulted anticlines of Furnace Creek Formation where the Furnace Creek fault zone (pl. 3) extends under the saltpan. In the center of Cottonball Basin the anticline is marked by a broad arch, 10 inches high in 1958, that partly ponds drainage in the northeast corner of Cottonball Basin FicurE 75.-Oblique aerial view of the Salt Creek Hills, an anticline of Pliocene and Pleistocene(?) beds dividing the saltpan (foreground) from the basin at Mesquite Flat (distance). View is northwest. Light-colored beds in the center of the anticline are Furnace Creek Formation. Dark gravel on the south flank of the anticline and gray gravels on the north flank are early Pleistocene and are uplifted less than the Furnace Creek Formation. southwest and is arched less than the lower Pleistocene gravel. Upper Pleistocene gravel forms terraces along the stream breaching the anticline from the Photograph courtesy of John H. Maxson. STRATIGRAPHY AND STRUCTURE Mme p> “tumult/mum sit FIGURE 76.-Escarpment of a Recent fault that displaces No. 3 gravel 6 feet at the foot of a late Pleistocene escarpment that displaces No. 2 gravel 50 feet. and separates it from the main drainage southward on the playa. Only at times of major floods does the ponded water discharge across the arch, and in pro- tracted dry periods dry salt crust forms. completely across the drainage line adding to the height of the arch. The tributary drainage in this part of Cottonball Basin is northwesterly, and on the smooth silty rock salt there are some northwest-trending ridges, one of them 5 feet high. The anticline coincides with a northwest-trend- ing gravity low, indicating that the anticline is not marked at depth by a major high on the bedrock. That the fill in Cottonball Basin is deep is confirmed by a drill hole 1,000 feet deep near the center of Cotton- ball Basin and on the arch extending northwest into the basin (table 19). From surface to bottom the hole encountered alternating layers of mud and salts that, so far as can be judged from the lithologic description, are entirely Pleistocene in age. The fifth anticline affecting the saltpan is at the Salt Creek Hills. It marks the north end of the saltpan and divides it from Mesquite Flat (fig. 75). This faulted anticline records a succession of uplifts. The latest, amounting to 10-25 feet, has raised late Pleistocene gravel which now forms terraces along the lower part of Salt Creek and along a tributary from the southwest. An earlier stage of uplift is recorded by the dome of the Pliocene and lower Pleistocene( ?) Funeral Forma- tion on which the structural relief is not less than 250 feet and probably is much more. Structural relief on the Furnance Creek Formation is at least a thousand feet, and probably more. The gravity contours indicate that relief on the bedrock basement is still greater. The gravity data also indicate another deep basin under Mesquite Flat. The anomaly here is larger than in the saltpan, and perhaps the fill of low density rocks is thicker. Four small faults on the saltpan disrupt the rock salt in the northern part of Badwater Basin (pl. 3). These faults are marked at the surface by linear breaks in the salt crust, but the displacement is small enough to View westward from near Shortys Well. be obscured by irregularities in the salt growths. The position of the fractures is of interest because they are on the projection of the Mont Blanco fault, a south west- trending rift in the Black Mountains. Whatever buried structure is manifested by these features may extend southwestward to the Hanaupah escarpment on the west side of the saltpan. FAULTS AND FOLDS ON THE GRAVEL FANS Many small faults displace upper Pleistocene de- posits on the gravel fans, and most trend roughly paral- lel to the contour of the fans. Many show two stages of movement. The older of the upper Pleistocene de- posits, the No. 2 gravel, commonly is displaced 50-75 feet by faults that displace the latest Pleistocene gravels 5-10 feet (fig. 76). There are good examples of faults showing two stages of displacement at the Hanaupah escarpment and at many places along the foot of the Black Mountains, especially at Mormon Point and near the mouth of Furnace Creek (fig. 47). Other faulted gravel fans are at Tucki Wash and at Trail, Starvation, and Johnson Canyons. Parallel faults in the gravels commonly bound gra- bens. Some, 10-25 feet deep and 500-1,000 feet wide, break the older (No. 2) of the upper Pleistocene gravels on the fans at Death Valley Canyon and Tucki Wash (pl. 3). Several small grabens only 25-50 feet wide are along the northwest side of the fan south of Badwater. The paved highway follows one of these and appears to be in a roadcut. In connection with the eastward tilting of the salt- pan, reference already has been made to the Recent fault that extends along the foot of the Black Mountains to Mormon Point (p. A100 ; see also Noble, 1926b). The most recent displacement along this fault is 5-10 feet, but at many places along it, the older, No. 2, gravel is displaced 50-75 feet, as it is at the Hanaupah escarp- ment. Late Pleistocene and Recent faulting along the front of the Black Mountains also is recorded by a series of A104 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA Ficur® 77.-Hanging valleys at the front of the Black Mountains, near the north end of the mountains at Desolation Canyon. Old valleys with U-shaped cross sections have been uplifted about 100 feet along this part of the mountain front, and the new valleys are narrow gorges incised into the bottom of the older, more open valleys. Miocene or Pliocene age. hanging valleys in the mountain block (figs. 77, 78). In the vicinity of Furnace Creek fan the hanging valleys are about level with upfaulted benches of No. 2 gravel and evidently are no younger than that gravel; they may be somewhat older. The height of the hanging valleys increases south- ward, which accords with other evidence that the moun- tains have been tilted northward as well as being faulted upward. It is difficult, however, to obtain very mean- ingful figures about the heights of the hanging valleys because of differences in the kinds of rock and ease of downcutting at the valleys. For example, at one canyon, Golden Canyon, in the northern part of the Black Mountains the hanging val- ley is at an altitude of -40 feet. A mile south, at Gower Gulch, the hanging valley is at sea level. About 11/4 miles farther south, at Desolation Canyon, the hanging valley is 100 feet above sea level. But the northern canyon is cut in soft beds of the Furnace Creek Forma- tion ; the middle canyon is cut into moderately resistant The bedrock consists of interbedded voicanic and sedimentary rocks of conglomerate at the base of the Furnace Creek Forma- tion; and the southern canyon is cut into a resistant block of dolomite. Part of the northward decrease in height may be due to northward tilting, but part prob- ably is due to greater erodability of the rocks north- ward. Another comparison that involves less variable chan- nels is provided by 2 gulches 1 mile apart on the side of the Badwater turtleback of Precambrian rocks. Each widens upward into a more open gulch, the northern one at an altitude of 800 feet ; the southern one at an al- titude of 1,200 feet. This suggested tilt of 400 feet northward is about the same as the northward tilt of the upper surface of the turtleback. The hanging valleys do not necessarily indicate north- ward tilt of the Black Mountains, but at least their heights do not conflict with such tilt. The hanging valleys are approximately the age of the No. 2 gravel; this is suggested by the occurrence of benches of No. 2 gravel near the mouth of Furnace Creek STRATIGRAPHY AND STRUCTURE that are displaced by about the same amount as nearby hanging valleys (fig. 47). The No. 2 gravel is broken by many faults having dis- placements of 50-100 feet, specifically at Mormon Point, Furnace Creek fan (fig. 47), East Coleman Hills, Mustard Canyon, Salt Creek Hills, Tucki Wash ( pl. 2), Blackwater Wash, Death Valley Canyon (pl. 2), Ha- naupah escarpment (fig. 76 and pl. 2), and the fans at Six Spring Canyon (pl. 2) and south. Upper Pleistocene gravels are downfolded into the northwest-plunging Texas Spring syncline separating the Black and Funeral Mountains (pl. 3). In this syn- cline Pleistocene deposits are less folded than the Pliocene and lower Pleistocene( ?) Funeral Formation, and the fanglomerate, in turn, is less folded than the Furnace Creek Formation (fig. 79)-further evidence that the deformation occured in multiple stages. FicurE 78.-Hanging valley at Gower Gulch at the front of the Black Mountains. above the apex of the fan. 776-623 O-66-8 A105 Upper Pleistocene gravel is folded and faulted at many places along the Furnace Creek fault zone where the zone plunges under the saltpan at the edge of Cottonball Basin. At Mustard Canyon Hills, for ex- ample, upper Pleistocene gravel unconformably over- lies and is anticlinally folded above upper Pliocene de- posits (fig. 80). Strike faults along the flank of this dome have displacements 5-10 feet down in the direc- tion of the dip. This late Pleistocene doming is 100 feet or more. Reference has already been made to the doming of the upper Pleistocene gravel at Salt Creek Hills across Cottonball Basin from the Mustard Canyon Hills. Evidence about tilting of shorelines of the upper Pleistocene lake, Lake Manly, is not at all satisfactory. Two hundred feet of eastward tilt and 300 feet of northward tilt since Lake Manly time is indicated- The floor of the old valley has been raised 50-75 feet - Furnace Creek Formation (extreme left) overlies Artist Drive Formation. A106 SW ..~"'.Black Mountains Artists Furnace Creek GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA NE Funeral Mountains Pz Pz; Texas Spring syncline - 4a 2 MILES | Ficur®E 79.-Section from the Funeral Mountains southwestward across the Texas Spring syncline and Black Mountains to the fault blocks at Artists Drive. tion; Qg, upper Pleistocene fan gravel. slightly folded in the syncline. Vertical scale not exaggerated. (p. A71) a reasonable supposition. But the deposits are discontinuous, and the correlations along and be- tween the two sides of Death Valley are uncertain. About all that can be concluded from the evidence pro- vided by the upper Pleistocene lake deposits is that this evidence does not conflict with what is known about the structural history. The same seems to be true of Panamint Valley (Maxson, 1950, p. 107). Evidence of late Pleistocene deformation also is pro- vided by the geomorphology of the gravel fans. The fans on the two sides of Death Valley are strikingly dif- ferent; those at the foot of the Black Mountains are Pz, Paleozoic formations; To, Artist Drive Formation ; Tf, Furnace Creek Formation ; QTf, Funeral Forma- The Artist Drive Formation is more deformed than is the Furnace Creek Formation, and the latter is more deeply folded under the Texas Spring syncline than is the Funeral Formation. Upper Pleistocene gravel is small, whereas those sloping from the Panamint Range are long and high. There is similar difference between the two sides of the Panamint Range (Murphy, 1932, p. 353). - The differences assuredly reflect the eastward tilting, probably not of the whole area but of individual fault blocks. Also, differences in the fans along the foot of the Panamint Range suggest there is a northward com- ponent in the tilting of that range. The fans at the north extend far into the mountains whereas those at the south extend only to the mountain front (fig. 66 and pl. 2). FicurE 80.-View along the southwest flank of the anticline at the Mustard Canyon Hills. formably overlaps the Furnace Creek Formation (light-colored beds) and is turned up 20° along the flank of the anticline. by John R. Stacy. Upper Pleistocene gravel (dark beds) uncon- Photograph STRATIGRAPHY AND STRUCTURE VALLEY FILL GRAVITY FEATURES The gravity contours shown on plate 3 are based on the complete Bouguer anomaly values. The data were reduced with an assumed density of 2.67 g per cm* (grams per cubic centimeter). The terrain corrections are large over all the area and locally extreme (more than 70 mgals at Telescope Peak) ; however, the terrain corrected data are considered accurate enough to justify the 5- and 10-milligal intervals used in contouring. The large local gravity lows in the valley are pro- duced primarily by the relatively low-density Cenozoic fill in the troughs. The more extensive variations are produced by density variations in the older rocks and perhaps by effects deep within the crust or in the upper mantle. - The quantitative interpretation of the gravity data is limited by uncertainties in the density of the rocks producing the anomalies. Horizontal and verti- cal changes in the density of basin fill produce gravity variations that cannot be distinguished from effects of relief on the bedrock-fill interface. In parts of Death Valley the problem of interpretation is further com- plicated by large gravity anomalies due to variation in the bedrock. Although the bedrock anomalies are more extensive than the basin anomalies, the two cannot al- ways be separated satisfactorily. Despite these limita- tions, the gravity data can be used to estimate the approximate thickness of the basin fills and to indicate structures that produce relief on the interface between the Cenozoic rock and the more dense older rock. Some of the gravity effects produced by deeper mass anomalies are also useful in studying the structural geology. In a basin several times as wide as it is deep, the amplitude of the gravity anomaly between Cenozoic fill and the dense older rocks primarily depend upon the density contrast and thickness of the fill. Computa- tions of the thickness of fill are no more accurate than the assumed density contrast. In Death Valley there are no drill hole or seismic depths to bedrock to serve as control for interpreting the gravity data, and densities are inferred from surface samples. Gravity studies elsewhere in the Great Basin indicate that the average density contrast between the Cenozoic fill and the older rocks is about 0.4 g per em®. The contrast may range from near zero to about 0.7 g per em®. If the contrast is 0.4 g per cm, a gravity anomaly of about 5 milligals will be produced by each 1,000 feet of fill. If the den- sity contract is as great as 0.7 g per cm, the actual thick- ness will only be about 60 percent as great as computed assuming a contrast of 0.4 g per em'. However, if the density contrast approaches zero, the actual thickness may be several times greater than the depth computed, using a contrast of 0.4 g per cm® (fig. 81). The depths A107 1 5 milIigals | ¥: Surface £2 1000 ft V Density contrast=-0.4 g per cm 3 > o o 0 3000 2000 1000 TO PRODUCE A 5-MILLIGAL GRAVITY ANOMALY, IN FEET 1 0 .2 .4 .6 .8 1.0 DENSITY CONTRAST, IN GRAMS PER CUBIC CENTIMETER THICKNESS OF SLAB REQUIRED FicurE 81.-Diagram illustrating the gravity anomaly produced by two-dimensional prism and the relationship between the amplitude of the anomaly and the density contrast between prism and the enclosing material. we infer from the gravity data are based on an assumed density contrast of about 0.4 g per cm. A gravity low extends the entire length of Death Val- ley. This low is divided into three principal areas of low gravity closure separated by the two high trends across the valley. The low areas are in Mesquite Flat, Cottonball Basin, and Badwater Basin; the two high trends coincide with the anticlines at the Salt Creek Hills and opposite Artists Drive. The gravity low in Mesquite Flat has the greatest relief of any of the lows in Death Valley. A part of this negative anomaly is probably related to the low anomaly values in the Cottonwood Range, but a local anomaly of 40-50 milligals is produced by rocks underlying the basin. This is the largest residual anomaly in the re- gion, and it indicates a subsurface basin containing about 2 miles of Cenozoic fill with the thickest section near the center of the basin. Near the south and east edges of Mesquite Flat are steep gravity gradients, which are interpreted as in- dicating faults with large vertical displacement. The fault indicated by the gravity data along the northeast side of the basin is part of the Furnace Creek fault zone. The steep gradient north of the front of Tucki Mountain probably indicates a fault trending a few degrees north of east. Not enough gravity data were obtained along the west side of the basin to define adequately the gravity gradient; however, a steep gradient, probably related to faulting, is indicated about 5 miles north of the mouth of Marble Canyon. The minimum anomaly values in Cottonball Basin are near the center of the valley along the east side of the playa. The maximum gravity-anomaly relief be- tween the floor of the valley and stations on bedrock in A108 920 910 900 MILLIGALS 8 0 M co c 0 15,000" 870 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA 920 910 900 890 sso __ M' 15,000 870 10,000' Panamint Range 5000' SEA LEVEL 5000' 2.3 g per cm? ---] 2.2 g per cm? Cenozoic rocks 10,000 2.4 g per cm* Pre-Cenozoic rocks 2.75 g per cm? 15,000" 10,000" Black Mountains 5000" Death Valley SEA LEVEL 5000' 10,000" 15,000" ] 4 1 1 5 MILES I FicurE 82.-Gravity and inferred bedrock profile across Badwater Basin. the Funeral Mountains is 43 milligals Along the northeast side of the Furnace Creek basin the gravity data indicate vertical displacement along more than one fault of the Furnace Creek fault zone. To the south the gravity anomaly bifurcates with one branch trending south down Death Valley and the other trending southeast along the Furnace Creek fault zone under the Texas Spring syncline. The gravity data indicate a considerable thickness of Ceno- zoic rock; under the Texas Spring syncline most of it must be Tertiary. This Cenozoic rock thins southeast- ward. The gravity data do not indicate faulting along the northeast side of the Black Moutains. The main branch of the gravity low in the Cottonball Basin continues down Death Valley to the Devils Golf Course opposite Artists Drive where a gravity saddle separates the low anomaly in the north from the low in Badwater Basin. This coincides with the buried anti- cline that has been confirmed by drilling (p. A102). The low gravity anomaly in Badwater Basin con- sists of two areas of low closures separated by a north- trending high down the west side of the saltpan, but the significance of these gravity data is obscured by the large regional gravity variation across the valley (fig. 82). We infer a structural high along the west side of the saltpan separating two areas of deep fill. The fill under the saltpan is computed to be 9,000 feet deep, of which two-thirds is estimated to be Tertiary. The interpretation of the western half of the profile is very doubtful because a major change from the assumed regional gradient would substantially alter the residual anomaly. South of Mormon Point and south of the area shown on plate 3 the axis of the gravity anomaly trends a little east of south and extends down the center of the narrow part of the valley between the Owlshead Mountains and the Black Mountains. In the Confidence Hills the mini- mum anomaly values occur directly over the hills, in- dicating that the greatest thickness of Cenozoic rock occurs under the hills and that the surface relief is not reflected on the bedrock surface. Gravity evidence in- dicates faulting on both sides of the valley in this area. The low anomaly diminishes to the south to a small low gravity closure north of the Avawatz Mountains. MAGNETIC FEATURES Aeromagnetic data were obtained along profiles in Death Valley flown at an altitude of 3,500 feet above sea level. 'One profile is along the axis of the valley and six are at widely spaced intervals across the valley (fig. 83). The local magnetic relief at the south end of profile A-A' is produced by Tertiary volcanic rocks. The gen- eral rise in the total magnetic intensity toward the north is about equal to the normal regional magnetic gradient. The gentle undulations several miles in ex- tent with relief of less than 100 gammas probably re- flect deep features, either relief on the top of basement complex or, more probably, compositional changes within the basement rock. The local anomaly between Badwater Basin and Cottonball Basin coincides with the buried anticline there. The anomaly is produced by a relatively shallow feature, probably volcanic material within the basin fill. STRATIGRAPHY AND STRUCTURE A109 x . 3 br ee % 11716; o 117°00' 116°45" $ 36°45" & 11 Ga Q4, Bl ‘i' +300 +200 +200 +100 A E‘ Mesquite Flat +100 0 ¥ Tucki Mountains 03 6 9 ser 36 30° Tues, E Wes/7 fe- at] A EXPLANATION £. 30 +300 he}, a 06 +200 0-150 +100 B0 Pre-Tertiary rocks 0 0 y -100 7 Fey Y =200 2 | *~~p 306 a +300 VERTICAL SCALE, IN GAMMAS 5 ~100 ~200 FIGURE 8$3.-Total intensity aeromagnetic profiles across Death Valley. sea level. Flight level is 3,500 feet above A110 Profiles B-B' and C-C' show the normal regional gradient across the valley without any large local anomalies. On profile C-C" there is an indication of the south end of the positive anomaly along the north- east side of Mesquite Flat, probably produced by the basement rocks. Profiles D-D', Z-E", and F-F" across the Badwater Basin show considerable local magnetic relief. Pro- files D-D' and Z-E" show a westward increase in the magnetic field along the west side of the valley, and at the west end of profile D-D', the anomaly has a peak. Depth estimates on this anomaly indicate that the feature producing the anomaly is within 1,000 feet of the surface. These anomalies coincide with the vol- canics and intrusions in the Amargosa thrust complex along the east foot of the Panamint Range. On profile D-D' there is a decrease in the total in- tensity as the Black Mountains are approached; on profiles Z-Z" and F-F"' the total intensity increases to- ward the Black Mountains. The latter two profiles are in the area where the older Precambrian complex makes up the core of the Black Mountains, and it seems prob- able that a major part of the rise in the total magnetic intensity is related to the elevation of the Precambrian rock. The local reversal near the east end of profile G-G' has a near-surface cause. The magnetic maxi- mum is where the older Precambrian rock of the Mor- mon Point turtleback extends across the profile. To the east of this outcrop is Cenozoic rock. The magnetic reversal may be related to a high over the older Pre- cambrian rock or to a low over buried volcanic rocks to the east. The southernmost profile @-G' has considerable magnetic relief west of the center of the valley. One anomaly is a local high over Shoreline Butte, which contains a considerable volume of basalt; probably the other anomalies to the west are also produced by vol- canic rocks in the Cenozoic fill. From Shoreline Butte the magnetic field increases eastward over the older Precambrian complex in the Black Mountains. CHANGES IN THE ALTITUDES OF BENCH MARKS Some evidence of continuing deformation in Death Valley is provided by the change in altitudes determined for bench marks between the original level surveys in the valley in 1907 and releveling in 1933-35 and 1942-43. In 1907 the U.S. Geological Survey surveyed level lines into Death Valley to provide vertical control for the 1:250,000 topographic maps of the region. Bench marks were set along a line which followed the road along the west side of Badwater Basin, crossed the valley floor at the Devils Golf Course and went around the north and east sides of Cottonball Basin and Mesquite GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA Flat. Another line crossed the valley from Daylight Pass to Emigrant Canyon. This early leveling al- though providing adequate control for the topographic mapping, was not sufficiently accurate to provide a measure of the regional deformation when compared with later leveling. However, local deformation with- in the valley is indicated by comparing the original alti- tude differences between bench marks in the valley with altitude differences determined on the later surveys (fig. 84). Unfortunately only a few of the original bench marks were recovered in the later surveys, and these pro- vide an incomplete picture. The indicated general decrease in altitude relative to the reference bench mark near Wingate Pass may be produced by systematic errors in the original data, but in general the indicated changes within the valley are probably real. The largest subsidence is 0.73 foot for a bench mark along the southwest edge of Badwater Basin. At a bench mark about 5 miles to the southeast near the end of the saltpan the indicated subsidence is 0.16 foot. This is consistent with continued subsidence of the Badwater Basin. On the east side of Cottonball Basin 3 bench marks over an interval of about 12 miles show changes of -0.07, +0.01, -0.65, and -0.03 foot. The bench marks with the -0.07 and +0.01 change are just south- west of the Kit Fox Hills fault with +0.01 bench mark closest to the fault. The - 0.65 bench mark lies between the Kit Fox Hills fault and the anticline in the Cotton- ball Basin. The -0.03 bench mark is south of the anti- cline and over the gravity nose extending northwest from the Black Mountains. The data for 3 bench marks southeast of Mesquite Flat indicate subsidence ranging from 0.28 to 0.68 foot. These indicated subsidences may be due partly to compaction of sediments in the valley fill and partly to structural deformation. SEISMIC ACTIVITY Death Valley is in a seismically stable area at the edge of a highly active area (fig. 69). Fifty miles southwest of Death Valley, epicenters are closely spaced, and a rather sharp northwest-trending line marks the northeast edge of the seismically active area. Only a dozen earthquake epicenters have been located in the valley or in the mountains adjoining it, and none of these was sufficiently intense to be felt by persons in the area. There is no historic record of earthquake damage. Apparently the last major earthquake origi- nating in Death Valley occurred 2,000 years ago when the floor of the valley was tilted 20 feet eastward and the 10-foot escarpment formed along the foot of the Black Mountains (p. A100). The geologic effects of that {36°00 _ EXPLANATION 35°45" —0 73 Benchmark and relative change in altitude in feet a 5 $ ga #. 10 miles Wingate Pass |——‘——-'—'—-'—-—‘————-—L-—————J a 0.00 x Reference 1907 43 2016 $ 117°15" - ec " 25) yoo si Aigr20. Flaunt 84 .-Relative changes in altitude of bench marks in Death Valley between unadjusted 1907 - _U.S. Geological Survey data slid adjusted 1933 and 1942-43 U.S. Coast and Geodetic Survey ; - data. The changes are relative to bench mark BM 1907 43 2016 near Wingate Pass. A112 earthquake, and perhaps its intensity, approximately duplicated those of the 1959 earthquake at Hebgen Lake in the West Yellowstone area. In the other direction, northeast of Death Valley, a series of epicenters alined northwesterly roughly along the California-Nevada boundary separates the Death Valley area from a more extensive stable area covering most of the eastern part of the Great Basin. This lat- ter stable area coincides with a regional gravity low (fig. 70). Finally, another series of epicenters is lo- cated along the boundary between the Basin and Range province and the Colorado Plateau. Data on earthquakes in the Death Valley region dur- ing the period from 1934 through 1958 were compiled and made available to us by C. R. Allen, of the Cali- fornia Institute of Technology. These data show 12 epicenters in the main part of Death Valley or on the adjoining mountain slopes. These quakes range in magnitude from 2.5 to 4.0 on the Richter scale. The uncertainty in the location of the epicenters is too great to justify any attempts to correlate them with known faults. Seismic-refraction data indicate that the crust under much of the Great Basin consists of two layers and that it thickens northeastward (Press, 1960; Berg and others, 1960; Diment and others, 1961). The upper layer or layers have a velocity of 6.3 kmps (kilometers per second) or less and are underlain at depths be- tween 20 and 25 km by a layer having a velocity of 7.6- 7.8 kmps. The base of this layer slopes northeastward from a depth of about 50 km in southern Nevada to about 74 km in northwest Utah. The underlying mate- rial has a normal mantle velocity of about 8 kmps. Such layering within the crust is not indicated west- ward from Death Valley to the Sierra Nevada (Carder and Bailey, 1958). Under the Sierra Nevada, velocities in the crust are uniform. The crust appears to be homo- geneous and at least 40 and perhaps more than 50 km thick. Gravity data (fig. 70) and seismic data indicate that the upper crust in the Death Valley area is little more than half that thick, say 25 km. Assuming these thicknesses, the base of the upper crust must slope about 15° westward from Death Valley. The slope to the northeast would be about half that. Death Valley ap- pears to be over a ridge on the mantle. TILTMETER MEASUREMENTS By Gorpon W. Green® METHODS Seven tiltmeter stations were established in the Death Valley area in 1958 and 1959 to determine if measure- able tilt was occurring. The location of the tiltmeter stations is shown on plate 3. A detailed description of GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA the portable liquid tiltmeters used in this study is given by Eaton (1959). Each tiltmeter station, except those in adits, was laid out in a nearly equilateral triangle with sides 30-50 meters long. At each apex a machined brass hub was set in concrete upon rock outcrops, and hub tops were established within +0.5 cm of a level plane. Varia- tions in the size and shape of the triangles were made because of local terrain. One station, Trail Canyon fan, was established by using large boulders embedded in gravel instead of bedrock outcrops. Temperature gradients between hubs and rapid changes of air temperature cause erratic readings. To avoid heating of the system by solar radiation, the tilt- meter was used at night, or when the sky was heavily overcast. Heat radiated from the ground at night, especially when the sky is clear, also makes observations difficult. A gentle wind can assist in maintaining a con- stant temperature in the system. Under ideal conditions, altitude differences between hubs can be measured with an error of less than three microns. Thus, if the hubs are 30 meters apart, a sen- sitivity of 1 part in 10 million can be realized. The precision of the measurements is checked by closing the measured altitude differences around the three sides of the triangle. In practice, closure errors as much as 50 microns were encountered because of the difficulty in maintaining the entire system at a constant temperature. Readings were considered valid if the closure error was less than 10 percent of the total change in hub altitudes. MEASUREMENTS Tiltmeter observations show that the ground surfaces in the Death Valley area are being tilted at present. The direction and magnitude of tilting varies from one station to another, and at any given station both direc- tion and magnitude vary from time to time. Figure 85 shows the tilting observed at five stations in the Death Valley area. The direction of tilting is consistent with the struc- tural geology and tends to follow the present dip of strata at each station. Tilting is to the northeast at Aguereberry Point, Trail Canyon, and Dantes View. These stations are located on blocks which have been tilted to the east or northeast. At Artists Drive, tilting is predominantly toward the southwest, although there is a distinct tendency at times to tilt southeastward. Here the Tertiary formations dip southeastward, and the overlapping early Pleistocene fanglomerate dips westward. Within the valley, tilting at Trail Canyon fan is chiefly toward the south, which accords with its position on the flank of the anticline north of Badwater Basin. STRATIGRAPHY AND STRUCTURE A113 N N 3 2 6 5 4 5 Artists Drive 4 2 E \/ Dantes View 3 S N E 4 1 3 - a 4 2 6\ E g E 6/ Aguereberry Point Trail Canyon 6 Trail Canyon fan 0 2 4 6 8 10 Leu " s e moe ol 21 MICRORADIANS 85.-Diagrams showing tilting observed in the Death Valley between successive observations. 1960 ; 6, February 1961. The rate at which tilting occurs varies widely. Ob- servations have been made at intervals of from 3 to 8 months, averaging about 6 months, and the total change of attitude, or tilting, that has occurred in the interval is measured. There is no evidence to indicate that the tilting has been at a uniform rate during the interval, nor is there any evidence to show that tilting occurred as a result of a single event or a series of events. It is convenient, however, to use "average" tilting rates when comparing tilting at different stations and intervals. area. Vectors are used to indicate direction and magnitude of tilting Dates of observations: 1, December 1958; 2, April 1959 ; 3, October 1959; 4, April 1960 ; 5, October An average rate as low as 0.15 microradian per month at Artists Drive and as high as 12 microradians per month at Aguereberry Point have been observed. Tilt- ing at an average rate of 0.9 microradian per month (11 microradians per year) seems to be common in the Death Valley area. Tilting at the rate of 11 microradians per year would produce an uplift of 581 feet over a distance of 5 miles in 2,000 years, an amount that is many times too large to be realistic. A1l4 During the years 1958-61, both the direction and mag- nitude of tilting have varied. At Aguereberry Point, Trail Canyon, and Artists Drive, reversals of tilting have occurred and, at the time this was written, the net tilt at some stations after 3 years was less than it was after 1 or 2 years. Observations over a much longer time are needed to establish the trends. RELATION BETWEEN TILTING MOVEMENTS AND SEISMIC ACTIVITY Because the Death Valley area is relatively free from earthquakes, it has not been possible to relate tilting to seismic activity in the vicinity of the tiltmeter stations. However, since the first tiltmeter measurements were made in May 1958, there have been five earthquakes of moderate intensity in the eastern Sierra Nevada and Owens Valley areas. These earthquakes, which are listed below, were not felt in Death Valley, although the quake of January 1961 was felt at the Defense mine in the Panamint Range where, according to the caretaker, several large rocks were rolled down the mountain. Richter Date Epicenter magnitude Jan. 5, 1959 Southern Owens Valley. 4.7 Aug. 4, 1959 Northern Owens Valley- 5.5 Jan. 28, 1961.___-_ Walker Pags___________ 5.8 Feb. 2, 1961___ Sierra Nevada, east of Big.Pine....s__-..s. 5.0 Oct. 18, Walker 5.2 There may be some relationship between tilting move- ments in the Death Valley area and earthquakes about 50 miles away. The average rates of tilting at Aguere- berry Point and Trail Canyon fan were greatly in- creased during the period between October 1960 and February 1961, but there was little change at the other stations. The direction of tilting at two stations, Trail Canyon and Artists Drive, was anomalous during this period, but most of the stations have shown some anomalous tilting in the past. EARLY PLEISTOCENE STRUCTURAL FEATURES Deposits of the Funeral Formation are exposed in fault blocks at the foot of the Black Mountains at Mor- mon Point and Artists Drive, in the Texas Spring syn- cline and in some of the anticlines northwest of it, in the Park Village fault blocks, Salt Creek Hills, and along Emigrant Wash (pl. 3). At all these places the deposits are mostly fanglomerate, but they include minor amounts of interbedded basaltic lava and volcanic ash. The fanglomerate is sufficiently faulted, folded, and eroded, so that its original fan form is no longer apparent. The structure of the lower Pleistocene fan- glomerates is accordant with that of the upper Pleisto- cene deposits, but the faulting and folding are much greater. GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA In discussing structural features involving the lower Pleistocene deposits, it is necessary to recall the uncer- tainties in correlating the deposits mapped as early Pleistocene. Only in two localities is there paleonto- logic evidence for dating the deposits mapped as Fu- neral Formation (p. A63). At Mormon Point the Funeral Formation overlaps and is faulted against the steeply dipping surface on the Precambrian metamorphic rocks (Drewes, 1959). The overlapped surface is a turtleback fault surface, very likely the Amargosa thrust, from which the overlying rocks have been stripped (Noble, 1941; Curry, 1954). Subsequent uplift of the turtleback has raised the fan- glomerate a few hundred feet above the valley floor, and the fanglomerate has been faulted valleyward along the contract of overlap. A high-angle fault at the north edge of the Funeral Formation separates it from the younger fill in the saltpan. Displacement on this fault is at least 200 feet (Drewes, 1959). There is differ- ence of opinion about the continuity of the turtleback fault surface with the Amargosa thrust. Noble (1941) and Curry (1954) connect them; Drewes (1959) sug- gests that the turtleback fault surface is a younger nor- mal fault. The structural relations at Mormon Point are dupli- cated along Emigrant Wash where the Funeral Forma- tion overlaps the west-sloping turtleback surface mark- ing the west side of the Tucki Mountain fenster, and the fanglomerate subsequently has been faulted down- ward along the old fault surface. The dip of the fault is about 25° to the west. Likewise, as at Mormon Point, a second fault, probably a high-angle one, marks the valley edge of the fanglomerate, and the displacement on this fault must also be down towards the valley, that is, to the west. The displacement on this high-angle fault is at least 500 feet. The faulting that involves the lower Pleistocene de- posits at Mormon Point and along Emigrant Wash raises problems about nomenclature of the faults. The autochthonous block at Mormon Point is regarded as that of the Amargosa thrust ; the autochthonous block along the turtleback at Emigrant Wash is that of the Tucki Mountain thrust fault (fig. 86). At both loca- tions two generations of movement are recorded. The latest movement, which involves the Funeral Forma- tion, is sufficiently later than the earlier one for the fault to have been folded anticlinally and the upper plate stripped from it, probably by detachment faulting. On Artists Drive the Funeral Formation overlaps middle and older Tertiary volcanic rocks. At the time this was mapped, in 1957, it was assumed that the con- tact was simply a depositional one of overlap. Question now arises whether faulting along that overlap contact STRATIGRAPHY AND STRUCTURE W Tucki Mountain fenster and turtleback A115 pen THRUST GRoTro CANYON FAULT Pro 2 3 MILES | | Fisurm 86.-Section of Tucki Mountain showing the Tucki Mountain thrust fault and its branches on the east side of the mountain, the turtleback on the west side, and the Funeral Formation in Emigrant Wash that overlapped the turtleback and that was later faulted down against it. p€k, Kingston Peak(?) Formation; pCn, Noonday(?) Dolomite; €pC, Sterling Quartzite and Lower Cambrian; €m, Middle Cambrian; €u, Upper Cambrian; O, Ordovician; S, Silurian; D, Devonian; QTf, Funeral Formation; Qg, upper Pleistocene fan gravel. Vertical scale not exaggerated. was overlooked. Faulting is suggested by the occurrence in the fanglomerate of granulated Paleozoic quartzite, like the chaotic blocks associated with the Amargosa thrust (Noble, 1941). Along the west side of the Artists Drive area, at the edge of the saitpan, are four southwest-trending fault blocks of Funeral Formation. The geomorphology of the ridges suggests that they are separated by as many southwest-trending faults and that each fault is down- thrown on the northwest side. The two northerly hills are opposite the anticline buried in the saltpan that separates Badwater Basin from the basins to the north (p. A102). The two southerly hills lie just north of the projection of the Mont Blanco fault and between its outcrop on the higher part of Artists Drive and the faults thought to represent its extension in the saltpan. The Mont Blanco fault and its projection in the Artists Drive area marks the southern limit of Funeral Forma- tion exposed in those fault blocks. South of the fault the Funeral Formation either is absent or has been faulted downward and buried under younger valley fill. North of the Black Mountains the Funeral Formation is downfolded in the Texas Spring sycline (fig. 79) and anticlinally folded over the East Coleman Hills (pl. 3). The structural relief of the Funeral Formation across the Texas Spring syncline and adjoining anticline is at least 750 feet and probably more nearly a thousand. This structural relief is four of five times that of the upper Pleistocene gravels, but probably less than half that of the underlying Furnace Creek Formation (Pliocene). In the Texas Spring syncline a block of the Funeral Formation ends southeastward at the Mont Blanco fault, which trends northeastward. Displacement on this fault, where it cuts off the fanglomerate, is down to the northwest. This direction of displacement is opposite to the apparent displacement farther south- west along the Mont Blanco fault where it enters the Tertiary formations and seems to have dropped the base of the Furnace Creek Formation downward a thousand feet on the southeast side against the Artists Drive Formation. Perhaps the displacement in the Tertiary formations is that of a tear fault with right-lateral displacement, and the horizontal displacement was taken up in part by downfolding of the Texas Spring syncline. In the Park Village block, between Cottonball Basin and the Funeral Mountains, the Funeral Formation forms a northwest-trending ridge bounded by faults. This probably is not a horst, however, because the fault along the northeast side of the ridge very probably is a faultline scarp. The displacement there probably is down to the west, that is, towards the valley, and the Funeral Formation probably has been stripped from the structurally higher fault blocks between the Park Village block and the Funeral Mountains. This in- terpretation is favored because the Tertiary formations along this fault and others paralleling it in the Furnace Creek fault zone are dropped down towards the valley. There may have been lateral displacement along the Furnace Creek fault zone (Curry, 1938a). There is some evidence of right-lateral displacement along sev- eral faults between the Park Village block and the Funeral Mountains, where the beds on the southwest side of the faults, the downthrown side, show southward drag. Right-lateral displacement also is indicated along faults at the west foot of the Panamint Range (Maxson, 1950, p. 107) and in the Confidence Hills (Noble and Wright, 1954, p. 157). In the Salt Creek Hills the Funeral Formation is involved in both anticlinal folding and faulting (fig. T5) and has a structural relief measurable in hundreds of feet (p. A108). Now we attempt to visualize how the physical geog- raphy and structure of the Death Valley area might appear if we undo the folding and faulting attributable to middle and late Quaternary time-that is, post-Fu- neral Formation. The distribution of the lower Pleisto- cene deposits shows that the Funeral Mountains, Black Mountains, and Tucki Mountain were in existence, but A116 structurally they were at least 1,000 feet lower, and probably more nearly 2,500 feet lower. If we raise the trough of the Texas Spring syncline (fig. 79) by 2,500 feet-that is, unfold it-dips in the Tertiary rocks in the Black Mountains are reduced al- most one half, to an average in the neighborhood of 20° 25°. Similarly, if the top of Tucki Mountain (fig. 86) were flattened structurally by 2,500 feet, the eastward dip of the Tucki Mountain thrust fault and the westward slope of the turtleback surface would be reduced to about 5°. The westward dip of the faults branching upward from the Tucki Mountain fault would be approximately doubled to an average of about 25°; the average east dip of the faulted Paleozoic formations would be re- duced to roughly 25°. No basis was found for estimating the amount of middle and late Quaternary uplift along most of the Black Mountains, but in view of the regional structural rise southward (p. A71, 88, 99) the probabilities are that the uplift towards the south was as great or greater than it was at the north. We assume the same amount-2,500 feet. To continue the attempt to visualize conditions as they were at the beginning of the Quaternary, it is nec- essary to remove something like 3,000 feet of sediment from the structurally deepest part of Badwater Basin and perhaps 2,000 feet from Cottonball Basin. It seems doubtful that Death Valley ever was 3,000 feet below sea level. On the contrary, it may even have had exterior drainage during part of the late Pleisto- cene time. Some of the late Pleistocene lakes may have connected with those at Soda Lake (p. A72) and possible exterior drainage from Death Valley is sug- gested by the abundant large boulders in certain upper Pleistocene (No. 2) gravel deposits (p. A65). Accord- ingly, it is reasoned that the floor of Death Valley was no lower than sea level, and probably was higher, at the beginning of the Quaternary. The Black Mountains probably were about half as high above the floor of the valley as they are now. There is reason to infer that, during the Quaternary, the main part of the Panamint Range was raised much more than has been assumed for Tucki Mountain or for the Black Mountains. The Funeral Formation at the west foot of Tucki Mountain (fig. 86) rises south- ward in 10 miles to an altitude of 7,400 feet. The fanglomerate may have had a source in or beyond what is now Panamint Valley west of the range (Axelrod and Ting, 1960, p. 22). This suggests the possibility that at the beginning of the Quaternary and during early Quaternary time a structural valley and trough extended southward from Mesquite Flat along the site GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA of Emigrant Wash and connected with the north end of Panamint Valley. Regardless of the continuity of the trough, its alti- tude probably was not more than half the maximum now reached by the fanglomerate. Whatever that altitude was, the difference between it and the present maximum altitude of the deposit (7,400 ft) is the amount by which the Panamint Range has been raised during middle and late Quaternary time. If this is assumed to be about 3,500 feet, the structures in the Panamint Range should be rotated westward 5°%-10° to restore dips as they were when the Funeral Forma- tion was being deposited. An upland surface of lower relief is represented on the Panamint Range by broad open valleys about 5,000-6,000 feet in altitude (Maxson, 1950, p. 102). The age of the open valleys is uncertain. One of them, Harrisburg Flat, is eroded partly in Funeral Forma- tion ; but the open valley could be as old or even older than the fanglomerate, and the subsequent erosion at- tributable to the fact that the valley provided a local base level for erosion of the fanglomerate. The open valleys contain upper Pleistocene gravels; therefore they must be middle Pleistocene or older erosional features. Most of the differential uplift of the Pana- mint Range above Death Valley and Panamint Valley has occurred since the broad open valleys were formed. LATE TERTIARY STRUCTURAL FEATURES The Furnace Creek Formation records the existence of a playa that extended from Mesquite Flat south- eastward across the site of the Salt Creek Hills, Cotton- ball Basin, Furnace Creek fault zone, and north end of the Black Mountains. Facies changes in the Furnace Creek Formation suggests that the playa did not extend southward along the trough that later became the Death Valley saltpan, because conglomerates in the formation in the northern part of the Black Mountains appear to have had a source far to the northwest in the northern part of the Panamint Range (p. A60). Had there been a playa extending southward along the site of the Death Valley saltpan, the gravels should have moved southward and not across the valley to the east side. The playa lasted long enough to accumulate more than 5,000 feet of fine-grained sediments, mostly derived from erosion of volcanic rocks. f Facies changes within the Furnace Creek Forma- tion are not known well enough to reconstruct closely the limits of the trough that contained the playa. The northeast edge probably was at or close to the Kit Fox Hills fault (pl. 3). Major displacement on that fault occurred after the Miocene(?) formations were de- posited in the Kit Fox Hills It is assumed that the STRATIGRAPHY AND STRUCTURE displacement of this fault, down on the southwest side, progressed while the Furnace Creek Formation was being deposited and that the scarp along the fault formed a northeast edge of the playa in which the Furnace Creek Formation was deposited. The southwest edge of the trough evidently coin- cided with the flank of Tucki Mountain. On the Black Mountains there was a pile of older volcanic rocks, the Artist Drive Formation, that shed debris northward into the playa, but those mountains were not high enough or dissected deeply enough to contribute Pre- cambrian debris to the Furnace Creek Formation. 'To what extent the mountains also had started to be raised as a major fault block is uncertain. Much of the uplift of the Black Mountains occurred after the Furnace Creek Formation was deposited. At the front of the Black Mountains the Furnace Creek Formation is cut off by the fault along that front, one of the Basin and Range type of block faults, and dropped at least 1,000 feet, and perhaps more, into Death Valley. Structural relief on the Furnace Creek Formation dipping off the north end of the Black Mountains could be as great as 7,500 feet (fig. 79), but this figure prob- ably is excessive. It seems unlikely that the Furnace Creek Formation under the Texas Spring syncline is so thick because the gravity data (pl. 3) indicate that the bedrock floor there is about 5,000 feet deep, and part of this is Pleistocene. The conflicting data provided by the gravity measurements and by the dips observed in the Furnace Creek Formation can be resolved by assuming that the playa shifted northeastward while the formation was being deposited. Such shift also is suggested by the fact that the sulfate and chloride zones in the upper members of the formation are north of their positions in the lower members (p. A62). If this shift is as- sumed, beds in the Furnace Creek Formation would offlap northeastward and would not be so thick under the Texas Spring syncline as would be assumed from the thick steeply dipping section exposed on the flank of the Black Mountains. The structural significance of this interpretation is that much of the uplift of the Black Mountains may have occurred while the Furnace Creek Formation was being deposited; perhaps no more than half, and pos- sibly much less, of the uplift of the Black Mountains need be attributed to early Pleistocene time after the Furnace Creek Formation had been deposited. We favor this interpretation because it resolves an apparent conflict between the structural and gravity data, and because it accords with an inferred northward shift of the salt zones of the Furnace Creek Formation. A117 At the Salt Creek Hills the Furnace Creek Formation is exposed in a sharply folded and faulted dome. The fold is asymmetrical. _ Its southwest flank is almost ver- tical where it is overlapped by the Pliocene and lower Pleistocene( ?) Funeral Formation ; the northeast flank dips 20°-45° northeastward. About 3,500 feet of beds assigned to the formation is exposed in the dome, and its indicated structural relief would be at least that much. Outcrops of upper Tertiary deposits northwest of the Salt Creek Hills (pl. 3) suggest that a major fault trends northwestward for at least 6 miles. Southeast- ward the fault probably underlies the ridge of lower Pleistocene gravel that extends into the saltpan south of Salt Creek. Projected across Cottonball Basin the fault would join with the frontal fault of the Black Mountains where that fault turns northwestward into Cottonball Basin. Very likely this is one of the faults through which ground water is discharged from Mes- quite Flat to maintain the extensive marsh on the west side of Cottonball Basin (Hunt and Robinson, 1960; see also Hunt and others, 1965). At the Salt Creek Hills, as elsewhere, the Furnace Creek Formation is more strongly folded than the lower Pleistocene fanglomerate, which, in turn, is more folded than the upper Pleistocene gravels. Reference has already been made to the curious Mont Blanco fault that trends northeast across the north end of the Black Mountains and Texas Spring syncline (p. A103). In the Black Mountains the base of the Furnace Creek Formation is offset to the right, as if the displacement were that of a normal fault down on the southeast side. Yet displacement of the Pleistocene beds in the Texas Spring syncline is down on the northwest. Many assumptions have had to be made as to condi- tions at the time the Furnace Creek Formation was deposited, but it is inferred that the playa represented by it occupied a long, narrow, southeast-trending struc- tural trough-at least 40 miles long and no more than 5 miles wide. - The trough may have branched southward along the site of the Death Valley saltpan, but this branch was higher than the playa; its subsidence to a level below that of the southeast-trending playa could have occurred late in Pliocene time, but it more probably occurred early in Pleistocene time. It has been inferred that the Black Mountains were raised structurally about 4,000 feet while the Furnace Creek Formation was being deposited, and that another 3,500 feet of uplift occurred during early Pleistocene time. To visualize conditions at the beginning of the Plio- cene, it is necessary to imagine the valley fill without the Furnace Creek Formation and younger sediments. The A118 thickness of these, as suggested by the gravity data, is less than the apparent thickness across the steeply dipping beds, and is assumed to be about 3,500-4,000 feet. To the degree that the Furnace Creek Formation in the valley is underlain by older Tertiary deposits, the thickness assumed for the formation there would have to be even less. Because the amount of uplift inferred at the Black Mountains is about equal to the thickness of sediments under the Texas Spring syncline, the relief across that part of the area probably was little different from what it is at present. There is no stratigraphic or structural evidence to sug- gest how the Panamint Range changed during this period. At least the northern part of the range was in existence because it provided some of the conglomerates in the Furnace Creek Formation. The part south of Tucki Mountain may have been much lower. It was certainly partly buried, and may have been largely buried, under the lower Tertiary volcanics that overlap the east side of the range. MIOCENE(?) AND EARLY TERTIARY STRUCTURAL FEATURES Deposits mapped as Miocene(?) are extensive in the Kit Fox Hills, east of Mesquite Flat, and they extend from there southeastward to the foot of the Funeral Mountains. The Kit Fox Hills fault, a straight high- angle fault and part of the northwest-trending Furnace Creek fault zone, extends for at least 30 miles along the southwest edge of the deposits. Displacement is down on the southwest side, and the gravity data indi- cate that displacement totals several thousand feet. Probably the Pliocene deposits southwest of the fault never extended northward across it (p. A117), but if they did, they have been stripped from the upthrown block. Part of the displacement on this fault is Quater- nary in age; much of the displacement is Pliocene, and most of it may antedate the Furnace Creek Formation. Along the northeast side of the Park Village block the Kit Fox Hills fault may be marked by a faultline scarp, as already noted (p. A115). Between the Kit Fox Hills and the Funeral Moun- tains are hills of Titus Canyon (?) Formation of Stock 3000' 2000" 1000' SEA LEVEL 1000' GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA and Bode (1935) (Oligocene) that protrude through the fan gravels. The northeast side of the Kit Fox Hills probably is a faultline scarp like that along the east side of the Park Village block. The scarp along the northeast side of the Kit Fox Hills faces northeast and overlooks older formations; it seems too straight to be simply a cuesta at the updip side of Miocene(?) fan- glomerate. This fault may be older than the Kit Fox Hills fault. Along the Keane Wonder fault at the foot of the Funeral Mountains, the Titus Canyon (?) Formation is faulted down against the Precambrian in the moun- tains. The fault dips 25°%-40° towards the valley, about the same as the dip of the Precambrian beds in that part part of the Funeral Mountains, which form a dissected turtleback (fig. 118). The occurrence of the Titus Canyon (?) Formation along this fault and turtleback surface is like that of the Funeral Formation at the Tucki Mountain turtleback in Emigrant Wash and at the Amargosa thrust fault and turtleback surface at Mormon Point (p. A114). These relations also are duplicated at the Copper Canyon tur- tleback (Drewes, 1959) (fig. 87). The Keane Wonder fault and the turtleback surface are continuous with the thrust faults at Boundary Canyon and Echo Mountain, along which Cambrian formations are thrust westward onto the Precambrian. The Titus Canyon(?) Forma- tion is faulted against the turtleback surface of the Funeral Mountains; but the main thrust appears to be pre-Titus Canyon in age, because to the north that formation overlies the upper plate. The similarity of this structure to those where the Funeral Formation has overlapped and has been faulted against turtleback sur- faces suggests similar histories. If so, the main thrust is old enough to have had the upper plate stripped from the turtleback surface before the Titus Canyon ( ?) Formation was deposited and faulted against it. At the north foot of Nevares Peak, beds mapped as Titus Canyon (?) Formation are dragged upward along a smooth fault surface dipping northward off the Cam- brian rocks that form that mountain. This feature 3000' 2000" 1000' SEA LEVEL 1000' FrGurRE 87.-Section of the Copper Canyon turtleback fault (generalized from Drewes, 1959). p€m, Precambrian metamorphic rocks; Tv, Tertiary volcanic rocks ; Ts QTf, Funeral Formation ; Qg, upper Pleistocene gravel , interbedded Tertiary sedimentary rocks and basalt ; STRATIGRAPHY AND STRUCTURE shows well on the State geologic map of Death Valley (Jennings, 1958). Mapping of the Miocene(?) formations between Cottonball Basin and the Funeral Mountains suggests that they aggregate more than 4,000 feet thick. But con- sidering that there must be some Titus Canyon ( ?) For- mation beneath these beds, the thickness seems to be ex- cessive. The gravity data suggest that bedrock is no more than about 4,000 feet deep in that area. The con- flicting data can be reconciled by assuming either that the Titus Canyon (?) Formation is denser than was as- sumed in compiling the gravity data (p. A107) or by as- suming an offlap relation in the Tertiary formations valley ward from the Funeral Mountains, as has been in- ferred for the Furnace Creek Formation northward from the Black Mountains. The latter interpretation seems reasonable because the outcrops of Titus Can- yon (?) Formation north of the Kit Fox Hills prob- ably never were buried under Miocene (?) fanglomerate as thick as that exposed in the Kit Fox Hills. In the northern part of the Black Mountains, the formation at Artists Drive dips northeastward under the Furnace Creek Formation. About 6,000 feet of beds are exposed, mostly volcanics, but these grade northward to and intertongue with playa deposits. The formation must thin northward under the Furnace Creek Formation, for the same reason that the Furnace Creek Formation must thin northward under the Texas Spring syncline. Gravity data indicate a total of about 5,000 feet of Quaternary and Tertiary deposits down to the bedrock under the syncline. Figure 88 is a dia- grammatic section illustrating the probable thinning northeastward of the Tertiary and Quaternary forma- tions on the northeast flank of the Black Mountains. Very likely the bedrock floor under the Tertiary formations is a series of fault blocks, but these cannot be satisfactorily reconstructed. While the formation at Artists Drive was being deposited, the axis of the trough was near A, B and C (fig. 88). At the site of the axis of the Texas Spring syncline, dips were towards the Black Mountains. At the front of the Black Mountains the formation at Artists Drive is faulted down about 5,000 feet. The blocks faulted down on the Death Valley side are re- ferred to as the Artists Drive fault blocks. The fault is the frontal fault of the Black Mountains, and it con- tinues northward and cuts off the Furnace Creek For- mation at the front of the north end of the Black Moun- tains. The Furnace Creek Formation is displaced at least 1,000 feet by the fault. If there was any displace- ment on this fault before the Furnace Creek Formation was deposited, the fault remained inactive while the formation was being deposited, because the facies A119 Sw NE Black Mountains Tal Tau TEXAS SPRING SYNCLINE Tfu oT Qs, FIicUuRE 88.-Diagrammatic section illustrating probable thinning and offlap of Tertiary and Quaternary formations from the Black Mountains northeastward to the Texas Spring syncline. Length of section about 6 miles. Axes of the troughs in which the forma- tions were deposited shifted progressively northeastward from A to F. Tal, Tou, lower and upper members of the Artist Drive Forma- tion ; Tf, Tfu, lower and upper members of Furnace Creek Formation ; QTf, Funeral Formation; Qg, No. 2 gravel. changes in the formation are cut off by the fault and are not related to it. The probabilities are that the frontal fault along the Black Mountains is a Quaternary struc- ture. Block faulting that outlined the present basins and range elsewhere in the region is regarded as largely of Quaternary age (Gilbert, 1941; Axelrod and Ting, 1960). On the other hand, there was earlier faulting along the northwest-trending Furnace Creek fault zone and along other northwest-trending faults in the region. Near Leadfield, in the Grapevine Mountains north of this area, the Titus Canyon Formation overlaps an earlier northwest-trending high-angle fault (James Gilluly, oral commun. 1960). The block faulting there- fore appears to have started as early as Oligocene time. The faulting has continued to the present, but since late Pliocene time the dominant trend of the faults has changed from northwesterly to northerly. If the north-south faults are mostly Quaternary, the uplift of the Black Mountains that caused the north- ward offlap and thinning of the formation at Artists Drive and the Furnace Creek Formation is attributed to folding rather than faulting. The formation at Artists Drive above the Artists Drive fault blocks also is broken by some flat faults that dip only 20°-40° towards Death Valley (fig. 79). Displacements are at least as great as 2,500 feet and in places may be very much greater. These structures were examined only in reconnaissance; they could be dismissed as megabreccia, except for the fact that in that area there are large chaotic blocks of Paleozoic rocks, hundreds of feet in diameter, and the ensemble suggests the possibility that major thrusting, like that of the Amargosa thrust farther south (Noble, 1941), has been overlooked in this part of the Black Mountains. One of the blocks of Paleozoic rock is dolomite wedged into the Tertiary formations at the frontal fault. Another is granulated quartzite, a monolitho- logic breccia, under (or in?) the Funeral Formation at A120 the northwest end of the Artists Drive fault blocks. The chaotic blocks probably are Cambrian-from the Zabriskie Quartzite and Bonanza King Formation. The blocks are suggestive of the Paleozoic blocks that are mixed with Tertiary ones and associated with the Amargosa thrust. There is no nearby source, and they must have been brought a long distance. The flat faults in the formation at Artists Drive may be branches from a larger fault that has not yet been identified. Volcanic rocks along the east foot of the Panamint Range in part at least are Miocene (p. A120), and are similar to and probably correlate with parts of the formation at Artists Drive. The eruptives are tilted 20° towards the east and overlap more steeply dipping Paleozoic formations (fig. 89), showing that about half the eastward tilt of the Panamint Range has occurred since those eruptions. GRANITIC INTRUSIONS Two large granitic intrusions, probably Cretaceous or early Tertiary, are well exposed at the west edge of the Death Valley area and are shown on the geologic map (pl. 1). One of these, the granite at Skidoo, crops out in an area of about 12 square miles along the north and east sides of Harrisburg Flat and extends southeast- ward into the head of Trial Canyon. The other, the granite at Hanaupah Canyon, occupies an equal area at the head of Hanaupah and Starvation Canyons. Smaller outcrops of granitic intrusions in the Panamint Range are in Wildrose Canyon about midway between the granites at Skidoo and at Hanaupah Canyon, in Warm Spring Canyon about 15 miles south of Hanau- pah Canyon, and along the east foot of the range. Although labeled on the map as granitic intrusions, and loosely called granite or granitic rocks, most of the intrusions would more nearly be classed as quartz monzonite porphyry. - However, the field study was in- terrupted before chemical analyses were made, and not GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA enough thin sections were examined to be certain of the range in composition of the facies of the intrusions. Under the circumstances, a more precise nomenclature for the few rocks studies would be misleading, and we use the term "granitic intrusion" throughout. The granites at Skidoo and at Hanaupah Canyon dif- fer texturally and, to a minor degree, mineralogically. The granite at Hanaupah Canyon is porphyritic with distinct fluidal structures; the dark phenocrysts are biotite and hornblende. The granite at Skidoo is mostly gneissic, but a part of it is porphyritic and has fluidal structures; the dark phenocrysts are biotite. The kind and amounts of trace elements in the two in- trusions and the trace elements that are in quantities too small to determine are similar, as brought out in table 25. The apparent greater concentration of lead and zinc in the granite at Hanaupah Canyon and the sill east of it, as compared to the granite at Skidoo, may be real, but additional analyses of the rocks are needed. The three-dimensional form of intrusions probably is the most important criterion for determining the re- lationship between the intrusions and the structural geology of the region ; this relationship, in turn, is basic for understanding the origin of the intrusions. Yet the form must remain a matter of considerable conjecture. We have attempted to apply some of the principles that have been learned about intrusive forms on the Colo- rado Plateau, where complexities are at a minimum and where exposures are far more complete. As G. K. Gil- bert wrote (1876) in citing the Colorado Plateau as a field for geologic study, "with the facts of structure conspicuous and beyond question, the mind is left free to search for causes." Before attempting to compare these intrusions with those on the Colorado Plateau, which is remote and structurally very different, some similarities may be noted between the intrusions of the Death Valley area and the individual plutons of the Sierra Nevada batho- W E 3000' 3000" 2000" 2000' 1000' 1000' SEA LEVEL SEA LEVEL 1000' 1000" 2000" 2000' 0 1 MILE Let L0 uf FiGUurE 89.-Section along the ridge 3 miles north of Trail Canyon. dipping 20° east overlap more steeply dipping Paleozoic formations. Felsitic lavas About half the eastward tilt of the Panamint Range has occurred since the lavas were erupted. O, Ordovician ; S, Silurian; D, Devonian; Tbr, Tertiary volcanic breccias, in part intrusive ; Ti, felsitic lavas of Tertiary age ; Qg, Quaternary gravel. fnr rz \_ STRATIGRAPHY AND STRUCTURE Tapur 25.-Trace elements in the granites at Skidoo and at Hanaupah Canyon Cu, Pb, and Zn determined by colorimetric methods by H. L. Neiman; other determinations are semiquantitative spectrographic analyses by E. F. Cooley, U.S. Geol. Survey. Values in parts per million, except Mg, which is given in percent] At Hanaupah Canyon At Skidoo, Element gneissic facies Boulder from |Sill along fault central east of the intrusion canyon 4 4. 26 80 280 50 90 80 300 1, 000 700 100 300 500 15 15 10 5 <5 7. 2 20 70 <5 T 5 15 30 30 1. 5 1. 5 1,000; Sn >10; Ge >20; Ga >20; Cd >50; Bi >10; In >10; Sb >200; Tl >100; Nb >50; Ta >50; W 100. lith. In the batholith the earliest intrusions were concordant and followed stratigraphic or tectonic boundaries (Cloos, 1932). Where the intrusions are crowded together, this concordance is masked because the later intrusions became guided by the walls or other structures of the earlier ones. There is abundant evi- dence that the intrusions emplaced themselves more by physical injection than by replacement, assimilation, or stoping (Knopf, 1929; Calkins in Matthes, 1930; Cloos, 1932, 1933, 1935, 1936; Bateman, 1958). The batholith plunges northward, and the intrusions at the north end are separated from one another like those to the east in the Death Valley area. The structural settings of the Sierra and Death Valley areas are quite different. Seis- mic and gravity data indicate that dense rock is shallow under the intrusions just west of Death Valley, but the main part of the batholith, including its north end, is underlain by a considerable thickness of light rock. But even where the intrusions of the batholith are crowded, there has been structural doming. The earliest intrusions of the Sierra Nevada batholith are along its west edge and are thought to be Late Juras- sic or Early Cretaceous (Knopf, 1929, p. 9). Eastward across the batholith the individual plutons are younger and generally less mafic (Calkins in Matthes, 1930; Cloos, 1936, p. 431-434; compare with Bateman, 1961, fig. 5). The intrusions in the Death Valley area may 776-623 O-66-9 A121 extend this pattern to the east. - These age relationships have long been recognized, and the problems they pose have been well stated by Ferguson (1929, p. 118) : It may be that the locus of intrusion moved gradually eastward from the Sierra Nevada to the Rocky Mountain region and that the areas of granitic rocks, intermediate in position between the Sierra Nevada batholiths and the Tertiary batholiths to the east are also intermediate in time (Lindgren, 1915, p. 260), or there may have been two distinct and sharply separated episodes of granitic intrusion. Whether the Death Valley intrusions should be re- garded as part of the composite Sierra Nevada batholith depends on one's definition of the batholith and on as- sumptions about the form of the buried parts of the intrusions. But regardless of whether the definition, which perforce must be arbitrary, includes or excludes them, clearly these intrusions are genetically related to each other and to the batholith. In the Death Valley area the granitic intrusions may have reached almost to the surface and may have developed into volcanic rocks at the surface. These volcanic rocks are inter- bedded with playa and related deposits ranging from Oligocene to Pliocene. The interpretation presented in this report is that the granitic intrusions in the Death Valley area are related to, but younger than, the batholith to the west and that they are related to, but older than, the vol- canism. The granitic intrusions in the Panamint Range are probably Miocene (p. A50) and are inter- preted as having immediately preceded the volcanism which continued long thereafter. The intrusions seem to have spread laterally along the Amargosa thrust fault and its branches and to have domed the overlying rocks (figs. 90, 91, 94, 108) because- 1. The intrusions have concordant roofs. There is dis- cordance to be sure, but the degree of discordance is no greater than the discordance of laccoliths at their type area, the Henry Mountains, Utah, where structural relationships are much simpler than in the Death Valley area. 2. The intrusions spread in incompetent formations where they are overlain by competent ones, a favored mechanism of intrusions that are demon- strably floored. 3. Because there is little evidence of reaction along the contacts and little other evidence of assimilation or replacement, the intrusions must have emplaced themselves by physical injection. Despite the large size of the intrusions, hydrothermal effects are little, if any, greater than around intrusions in the Colorado Plateau. 4. The volumes of the structural domes over the intru- sons are too small to accommodate physically in- A122 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA W € 12,000 - 12,000" 10,000 - 10,000" 8000' -f: - 8000" 6000' Burro Trail fault and sill - 6000° 4000 47 :- \ % Zone of |- 4000' al volcanism 2000" |- 2000" SEA LEVEL SEA LEVEL FicurE 90.-Cross section of the granite at Hanaupah Canyon. cambrian metamorphic rocks; Formation. jected crosscutting intrusions as wide as these (see Hunt and others, 1953, p. 139). 5. Sills that extend from the granite at Hanaupah Canyon along thrust faults, like the Burro Trail fault and others north of the intrusion (pl. 3), show that the granite is later than the thrust fault- ing and that part of the granite demonstrably spread laterally along the faults. Except for their large size, the intrusions are much like those on the Colorado Plateau. They are not like the individual intrusions in the Sierra Nevada batholith where, although the plutons seemingly were forcibly injected, there is abundant evidence of steep contacts (Bateman, 1958; Sherlock and Hamilton, 1958). Nor is there evidence of much assimilation or stoping like that described at some intrusions in the Mojave Desert (MeCulloh, 1954, p. 21). Intrusions in the Great Basin probably are floored to a far greater degree than has generally been assumed. Few workers have considered this problem. Noble (1941, p. 963) inferred that the granite under the Amargosa thrust fault in the Virgin-Spring area was controlled by the fault because the roof of the granite parallels the fault (fig. 108). Hewett (1956, p. 63) interpreted the Teutonia Quartz Monzonite in the Ivan- pah quadrangle, 75 miles southeast of Death Valley, as having been intruded along one of the eastward directed thrust faults He states (p. 63), "There is nothing about the relations of the monzonite to the limiting p€n, Noonday(?) Dolomite; pCj, Since the faulting and intrusion of the granite, the Panamint Range has been tilted 15°-20° east. Amargosa thrust Length of section 8% miles; vertical scale not exaggerated. pC, Pre- Johnnie Formation; pCs, Stirling Quartzite; €w, Wood Canyon rocks in any part of the region to indicate that any large part of it is a crosscutting stocklike mass." Granitic intrusions in the Mina quadrangle in west- ern Nevada have been interpreted as having spread laterally at the thrust faults (Ferguson and others, 1954), and one at the south end of the Panamint Range, in Warm Spring Canyon, is intrusive along a fault (Wasserburg and others, 1959). Granitic intrusions in the southern part of the Panamint Range have em- placed themselves along faults (Johnson, 1957, fig. 2), and some in the Silurian Hills were first localized by the thrusting and later displaced by it (Kupfer, 1960). Intrusions in the Darwin area also have the flat form (W. E. Hall, written commun, 1964). Mackin (1947, 1954) has shown that doming in the Iron Springs district in southwestern Utah is quite like that on the Colorado Plateau. He has been the principal advocate (1960) of the idea that igneous in- trusions have been underestimated as a cause of many of the structural features in the Great Basin. But such interpretations are exceptional for the Great Basin. In most reports the form of the intrusions either is ignored by drawing cross sections away from them, or the cross sections are drawn to indicate that the intrusions widen downward. A case can be made for this interpretation by assuming that the Great Basin is underlain by a granitic batholith and that the stocks are minor apophyses rising upward from it. In favor of such interpretation is seismic refraction evidence CesT STs STRATIGRAPHY AND STRUCTURE suggesting that the crust under the Great Basin con- sists of 2 layers, the upper one having a velocity of 6.3 kmps or less, and the lower one having a velocity of T.6-7.8 kmps (Press, 1960; Berg and others, 1960; Diment and others, 1961). Such interpretation, how- ever, is not presented, and one gains the impression that the stocks were drawn in cross sections to widen down- ward chiefly to conceal and dispose of complex struc- tures at depth. A bad effect of this practice, however, is that there has been too little thought given to the three-dimensional forms of the intrusions, the mechanics of how they became emplaced, and their part in the structural history of this complex region. The granites at Skidoo and at Hanaupah Canyon have domed roofs of Precambrian sedimentary forma- tions that are roughly concordant with the upper sur- faces of the granites. The degree of discordance is little greater than over laccoliths in the Henry Mountains where, despite the simplicity of the structure of the host rocks, even the most orderly laccoliths cut across several hundred feet of beds in a mile. Extensive con- cordant roofs, like those on the granites at Skidoo and at Hanaupah Canyon, imply equally concordant floors. Moreover, the area domed by the granites at Skidoo and at Hanaupah Canyon is too small and has too little structural relief to be attributable to doming by steep- walled crosscutting intrusions having cross sections as wide as the exposed granites. On the Colorado Plateau, stocks 1 mile in diameter produce domes having a base 6 miles in diameter and a structural height of almost 114 miles (Hunt and others, 1953, p. 189). The intrusions in the Panamint Range are much wider than those in the Colorado Plateau, but the doming is not corresponding- ly greater. This fact also suggests that the granitic masses have spread laterally and that the steep-walled stocklike source for them is much smaller than the area of granite at and near the surface. Finally, the roof and side contacts of the intrusions are sharp and contact metamorphism is slight, both of which indicate that there was no great amount of reac- tion that would cause replacement or assimilation of the country rock by the granite. Indeed, the contact metamorphism is more like that around the floored in- trusions than around the stocks on the Colorado Plateau. The occurrence of a pyritic and an epidotic zone of alteration over the west side of the granite at Hanaupah Canyon is the basis for inferring that the source of that intrusion is under its west side (fig. 90). Pyritic alter- ation and considerable discordance along the west side of the granite at Skidoo suggest that its source is under its west side. The eastern edge of the granite at Skidoo is inferred to be along the north-trending monocline that forms the head of Tucki and Blackwater Washes. A123 The intrusions therefore are interpreted to be wedge shaped, the form to which the names sphenolith (Burck- hardt, 1906) and harpolith (Cloos, 1921) have been applied. GRANITE AT SKIDOO The granite at Skidoo (an abandoned mining camp) crops out in an area about 12 miles long and 1-5 miles wide, elongated north-northwestward parallel to the general strike of the enclosing formations. The age is presumably Cretaceous or Tertiary. The southwest contact is steep and crosscutting; but the roof is con- cordant, east dipping, and mostly in the Kingston Peak(?) Formation although cutting upward discord- antly to the Noonday(?%) Dolomite. The structural form (fig. 91) is broadly wedge shaped thinning east- ward. The contact along which the intrusion has spread al- most certainly is a thrust fault of the Amargosa fault system. The contact between the Kingston Peak(?) Formation and Noonday ( ?) Dolomite is a fault ; so also is the contact between the Noonday(?) Dolomite and Johnnie Formation. The spreading of the granite has obscured evidence for faulting at the plane of intrusion, and not enough is known about the local stratigraphy of the Kingston Peak(?) Formation and Noonday (?) Dolomite to estimate the thickness of beds cut out by faulting at any particular place-although locally more than a thousand feet of beds have been cut out. The amount of lateral displacement along the fault is uncertain. The granite at Skidoo has spread in the Kingston Peak(?) Formation, which is an incompetent unit, and under the Noonday (?) Dolomite, which is a competent unit. - This relationship duplicates that on the Colorado Plateau where the favored horizons for spreading of floored intrusions are in the upper part of incompetent formations that are overlain by competent ones (Hunt and others, 1953, p. 142). The roof of the granite at Skidoo is well exposed almost continuously from the head of Trail Canyon to a little beyond the abandoned mining camp at Skidoo. In Trail Canyon the roof is Noonday(?) Dolomite. This roof rises steeply westward to the summit where it flattens. Along the summit from Trail Canyon northward along the east side of Harrisburg Flat, the roof of the granite and the overlying dolomite and lime- stone dip gently 5°%-10° E. The steep dip noted in Trail Canyon, however, extends northward as a mono- cline 11/4 miles east of the summit, and this fold prob- ably marks the eastern limit of the granite. This in- terpretation is based partly on the structure (fig. 91) and partly on the occurrence of small intrusions of alaskite along the monocline. The granite, therefore, A124 GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA 0 C $ o o $4 117°05" 2 tad o £ [it to m u. & = o c Z 9 = a % 0 oC o (a 2 [a) ol 2 = - el > w \ p aS opy A yA [PC = VEN g O w 2 w Z 3 o O m ® 3 Hee 0 3 3 AHVNHSLIYNO AHVILHTL any HO a § Z g g 8s z 0 .s 8 .s E a % 8 s m < 3 £ | 8 E e Z f T & m m < E & to P €] # . & | 4 3 & 5s : 3 E s L 5 w G 8 & 8 M FIGURE 91.-Fence diagram, isometric projection, illustrating inferred shape of the granite at Skidoo. STRATIGRAPHY AND STRUCTURE is inferred to have a maximum thickness about equal to the structural relief along the monocline, that is, about 3,500 feet. At the head of Trail Canyon the Noonday (?) Dolo- mite above the granite is about 800 feet thick. Within a mile and a half to the north, however, the dolomite has thinned to about 200 feet, probably by faulting, and about 200 feet of shaly beds of the Kingston Peak(?) Formation lies between the dolomite and the top of the granite. Farther north the dolomite again thickens to about 1,000 feet; it overlies the granite at 2 places, but 2 miles southeast of Skidoo, 500 feet of shale, quartzite, and stretched-pebble conglomerate belonging to the Kingston Peak (?) Formation lies under the dolo- mite and above the granite. The steep west wall of the granite cuts across faulted and folded beds, mostly belonging to the Kingston Peak(?) Formation. At 2 places about 3 miles south- east of Skidoo the west wall is dolomite, but whether this dolomite is part of the Noonday(?) Dolomite or a part of the Kingston Peak(?) Formation was not determined. In the vicinity of Skidoo the granite is in the Kingston Peak(?) Formation, and the roof plunges northwest- ward. Westward from the north end of Harrisburg Flat and northward along the west edge of the intrusion, Pliocene and lower Pleistocene(?) Funeral Formation has been faulted against the granite. This roof of the granite is sheeted roughly parallel to the faulted con- tact along Emigrant Canyon ; the sheeting and the roof contact strike north and dip about 25° W. Steeply dipping fissures in the granite also strike north. Dikes of basalt intrude both the sheeted joints and the steeply dipping fissures. Along the canyon there are at least 5 dikes in the upper 250 feet of the granite; their thick- nesses range from 6 inches to 10 feet. These dikes are not related to the granite. Probably they are early Pleistocene in age and related to the basaltic lavas and minor intrusions that occur nearby in the Funeral Formation. The southern third of the granite at Skidoo is por- phyritic and clearly an intrusive igneous rock; but the northern two-thirds of the intrusion is banded gneiss, and many outcrops there look like metamorphic Pre- cambrian rocks. Along the monocline east of the out- crop of the granite are small intrusions of alaskite (fig. 92). The contacts along both the roof and west wall of the granite at Skidoo are sharp. In the porphyritic facies dike-like and sill-like apophyses of granite extend up- ward into the fractured roof rocks. The contact zone commonly is a few inches wide (fig. 93), about twice as wide but otherwise similar to roof contacts over lac- A125 Fisur® 92.-Micrographs of thin sections of the granite at Skidoo. a, quartz; fo, orthoclase; fm microcline; fs, sericitized feldspar ; ic, argillized feldspar; go, groundmass oriented; gn, groundmass not oriented. Diameter of field, 2.5 mm. A, Gneissic facies. Quartz with strain shadows (30 percent) ; euhedral feldspars (20 percent) altered to sericite and to clay; anhedral microcline (20 percent) ; muscovite (10 percent) with ragged sides and ends and embayed with quartz; and a feldspathic groundmass (20 percent) with sericite, some of it oriented and some not. B, Porphyritic facies. Eubedral plagioclase and orthoclase (30 percent) altered to sericite and to clay. These have clear rims of low index feldspar and are set in microcline (about 30 percent) which occurs in ir- regular growths. (Other common minerals are quartz (about 30 percent) and biotite (about 10 percent). There is also a trace of augite (not shown). C, Alaskite facies. Consists of quartz (30 percent) ; clouded feldspar, probably mostly orthoclase (60 per- cent) ; sericite (10 percent) and occasional phenocryst of muscovite (M). Both the quartz and feldspar occur as euhedral crystals in a paste of anhedral quartz and feldspar. A few aggregates of pheno- crysts of the same minerals are rounded and may have been floated in from porphyry facies from which this is believed to have been derived. coliths in the Henry Mountains on the Colorado Pla- teau. Four or five inches from the contact is normal porphyry with phenocrysts as much as 1 inch in diam- eter. Nearer the contact is a zone in which the crystals A126 Granulated layerj B a n de d a n d sheared zone; grains are \ quartz an d feldspar Porphyry contain- ing s maller phenocrysts and much biotite T (dark) Coarse porphyry containing large grains of feld- spar (lined), , smaller ones of q uartz an d feldspar (clear), and biotite (dark) GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA 93.-Hand specimen of roof contact of the porphyry facies of the granite at Skidoo. Natural size. are small and not very distinct in hand specimens. A selvage 1 or 2 inches wide at the contact is sheared and banded. At the contact is a granulated layer 2 or 3 mm wide. Contact-metamorphic effects are surprisingly slight. Shale and schist are baked to hornfels, and carbonate rocks are bleached-effects that are only a little more intensive and extensive than the alteration zones above the much smaller floored intrusions on the Colorado Plateau. The gneissic facies may be an ancient granite. There is much brecciation, and cataclastic structures are strongly developed along the roof contact. Quartz veins in the gneissic facies are numerous, and some, like those at Skidoo, have produced gold. GRANITE AT HANAUPAH CANYON A granitic intrusion at the head of Hanaupah Canyon crops out in an oval area about 6 miles long and 3 miles wide extending from Hanaupah Canyon to Starvation Canyon. The roof is highly domed, much more sharply domed than that of the granite at Skidoo. Across the north end of the intrusion and along the northwest side of the roof is Noonday (?) Dolomite. Along the south- east side, which, however, was examined only from the air (p. A8), the granite may cut discordantly upward to the Johnnie Formation. The structural relief across the top of this intrusion is at least 6,000 feet, but half of this can be attributed to the homoclinal eastward dip of the country rocks. The doming, superimposed on the homoclinal eastward dip, amounts to about 3,000 feet and could be produced by a partly floored intrusion about that thick (fig. 94). The only part of the granite at Hanaupah Canyon that was examined on the ground is the northern and northwestern contact from 4,000 feet altitude in Han- aupah Canyon to the summit at 10,000 feet. Along this contact the (?) Dolomite is bleached and has been dragged steeply upward; but the drag is not so steep as the side wall of the granite, which in places cuts upward to the Johnnie Formation. A127 STRATIGRAPHY AND STRUCTURE AHVILHTL lel snojDvL34D NYVIHEWNYVO3Hd C yedntuep jt oy} Jo odeys Sups1jsn|I; 'uoppoofoid ormowios}; 9000,f[-*¢G WHOOLMI uoreuntog (})yEaq uojs3uty meaw; arn wa- @qrwoj0( (}) de uoneuLto,f aruuyop C-" _- 3JON34 10 NOILVDOT ONIMOHS dVMW sun" SITIW Z I 0 7 }. a lise x. ; Js Blxy as ih seee oral ; ./.\/x .\\\, 7 “I fae ME e tr d /.4/\.\«,.//\,/\\ ai p j /.\.—\.\, A/\\./ /.// ata alri So N a' 9g 7x p li yuya s: 'a lel 4s % x" Ly) FRC x oy is ) A ~r3d4 - | I auz1ren6 Sums s ...m:0m a ts 40 IG suotsn.qu1 on fuein * fe Aux cl * ¢ rsz\ x 6 ; aA $> as .. h 4 ¢ \././.\ %. ful f av 6 al (2 t AA LTT sod 101 .9€ SIW Z A128 FiGuRE 95.-Micrographs of thin sections of the granitic intrusion at Hanaupah Canyon and associated sill. Q, quartz; F, feldspar; H, hornblende; B, biotite; M, magnetite. Diameter of field, 2.5 mm. A, Quartz monzonite from the intrusion. Phenocrysts of feldspar are mostly oligoclase mottled with potash feldspar. Most of the rock is a graphic intergrowth of quarts and clouded feldspar stippled areas). Dark minerals are biotite, hornblende and mag- metite. iB, Monzonite porphyry from a sill along the Burro Trail fault. iPhenocrysts of oligoclase have strongly argillized borders. Hornblende is altered to calcite, magnetite, and epidote(?). Quartz occurs as deeply embayed phenocrysts and as secondary nests. Magnetite occurs in small phenocrysts, some of which are embayed like the quartz. [The groundmass, strongly argillized, consists of lathlike and rectangular feldspars and tiny specks of magnetite. The granite is a homogeneous porphyry as far as could be judged by examining many boulders from it along Hanaupah and Starvation Canyons and by ex- amining the north edge of the intrusion. The rock contains large phenocrysts of K-feldspar with rims of oligoclase associated with quartz, biotite, hornblende, and some magnetite (fig. 95). Trace elements in the granite at Hanaupah Canyon (table 25), as already noted, are similar to those in the granite at Skidoo. The contact at the edge of the granite is sharp like the roof and sides of the porphyry facies of the granite at Skidoo. Porphyry containing large phenocrysts oc- curs within a few inches of the contact, but at the con- tact the porphyry is fine grained and granulated (fig. 93). GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA Contact-metamorphic effects consist of bleaching of the Noonday(?) Dolomite and developemnt of nests of tremolite and calcite. Minor quantities of sulfides have been deposited along faults and fissures extending north from the intrusion. In addition, under the sum- mit ridge for 2 miles north from Telescope Peak, the lower part of the Johnnie Formation and upper part of the Noonday(?) Dolomite are stained brown, presum- ably because of oxidation of disseminated iron sulfide. Northward from this belt along the summit ridge for another 2 miles the joints and fissures in the Johnnie Formation are coated with epidote. On the Colorado Plateau, alteration zones like these are found only around the stocks, not around the lac- coliths. The position of these alteration zones, there- fore, suggests that the source for the granite at Hanau- pah Canyon is under the west side of the intrusion, and this is a basis for the interpretation given on figure 94. The alteration zones extend 4 miles north-northwest ward from the granite to within 2 miles of a granitic body in Wildrose Canyon. The granite in Wildrose Canyon, which is gneissic and contains biotite, more closely resembles the granite at Skidoo than the granite at Hanaupah Canyon. Dikes and sills extend 2 miles northward from the granite of Hanaupah Canyon, and others occur along the Burro Trail and other faults east of the granite (figs. 94, 96). The dikes and sills are 5-10 feet thick and provide a measure of the fluidity of the magma that was intruding. By contrast, at the laccolithic mountains on the Colorado Plateau, only the latest intrusions were sufficiently fluid to form thin dikes and sills; the earlier ones were highly viscous. The rocks comprising the dikes and sills tend to be finer grained than the porphyry in the main intrusion, but many closely resemble it (fig. 95). Moreover, their content of trace elements is similar (table 25). Almost certainly the sills along the thrust faults east of the granite are connected with it like those that extend to the north. The sills along the thrust faults locally have chilled contacts against the faulted surfaces and clearly are later than the faulting. However, there was renewed movement on some thrust faults later in Tertiary time; possibly later movement on the Burro Trail and neigh- boring faults followed shaly layers above or below the sills without severely fracturing those intrusions. These sills along the faults are much altered, but it was not determined to what extent the alteration was caused by deuteric action, hydrothermal activity, or to weathering due to ground water percolating along the faults. Throughout the Panamint Range, the thrust faults have served as aquifers. STRATIGRAPHY AND STRUCTURE CHAOTIC COMPLEX ALONG THE AMARGOSA THRUST The chaotic complex along the Amargosa thrust, along the east foot of the Panamint Range (p. A51), is structurally arched. Its high part is between Hanaupah and Death Valley Canyons where the thrust fault and underlying Precambrian metamorphic rocks are exposed (fig. 96). The Precambrian rocks are intruded by a granitic mass and a still younger swarm of felsite dikes (fig. 97). At Hanaupah Canyon the upper plate of the thrust is Precambrian Stirling Quartzite. Farther north the upper plate consists of progressively younger Cambrian formations. At Death Valley Canyon these arched rocks of the complex plunge northward under a mass of volcanic rocks having interlayered slabs of Paleozoic dolomite (fig. 98) , a mixture highly suggestive of the chaos which was described by Noble (1941) in the Virgin Spring district 20 miles southeast of here. The swarm of felsitic dikes that intrude the granitic mass and the meta- morphic rocks south of Death Valley Canyon also in- trude the chaos north of the canyon. The chaos also is cut by felsite plugs. The thrust and the underlying metamorphic rocks and granitic intrusion are not exposed farther north or south, but in both directions the complex is represented by lavas, dikes, and areas of hydrothermal alteration. Very possibly the granitic mass that underlies the high- est part of the structural arch may thin northward and southward and be a main cause of the arching. The thrust fault is well exposed where it crosses the divide a mile north of the mouth of Hanaupah Canyon. There the upper plate is Stirling Quartzite dipping about 45° E; the fault dips 15° W. (fig. 96). The lower part of the quartzite is thoroughly granulated, in part mylonitized, in a zone about 50 feet thick. Below this, the myloni- tized quartzite is mixed with crushed Precambrian met- amorphic rocks from the lower plate. The metamorphic rocks include augen gneiss, feld- spar-biotite gneiss, biotite schist, and quartz gneiss. The most conspicuous and most abundant rock is the augen gneiss (figs. 99, 100), which consists of augen of feldspar as much as 1 inch long in a matrix of feldspar and quartz cut by stringers of biotite. The augen make up perhaps 15 percent of the rock. Just below the thrust the augen gneiss is finely layered, and augen are few. The rock there grades into feldspar-quartz-biotite gneiss. The augen gneiss is about 50 percent quartz. The augen, which constitute about 20 percent of the rock, are altered (silicified or argillized ?) feldspar, probably microcline or albite. Some augen contain irregular grains of quartz, plagioclase, and biotite. The rest of A129 the rock is about half plagioclase and half biotite, the latter occurring mostly as bands or layers in the gneissic structure. Zircons from several specimens of augen gneiss are rounded and colorless (Ralph L. Erickson, written common., 1961) (fig. 103). Their lead-uranium and lead-thorium ages are greater than a billion years (T. W. Stern, written commun., 1965). Some facies of the biotite gneiss contain considerable potassium feldspar, as much as 25 percent. Other con- stituents are quartz, 40 percent; plagioclase, 20 percent ; and biotite, 15 percent. - Other facies are without potas- sium feldspar and contain 60 percent quartz, 20 percent plagioclase, and 15 percent biotite. In some specimens of these rocks Erickson (written Commun., 1961) found two kinds of zircon (fig. 103), mostly colorless and rounded like those in the augen gneiss, but some eu- hedral and pale pink with rodlike inclusions. More work is needed to determine how these types are dis- tributed in the different facies of the biotite gneiss. Trace elements in the augen gneiss and biotite gneiss are given in table 26 (p. A140). The gneiss is strikingly foliated and the dips are to the west. There are belts 50-250 feet wide in each of which the dip of the foliation increases westward from about 20°%-70° (fig. 101). The parts of the belts having the most steeply dipping folia generally are occupied by dikes. The dikes cutting the augen gneiss range in width from stringers less than 1 inch to dikes about 6 feet wide. Contacts are sharp and most of them show dis- tinct chilled edges, although some contacts are obscured by subsequent shearing. The age of the metamorphism and the age of the metamorphosed rock are not clear. The rock is Pre- cambrian (see above), but some of the metamorphism may be very much later, because biotites from these same rocks give a late Miocene potassium-argon age (T. W. Stern, written commu., 1965). This could ac- count for the close spatial association of the augen gneiss with so much volcanic activity and with the Amargosa thrust fault, not only here but also in the Virgin Spring area (Noble, 1941). A close relationship between the fissuring that localized the dikes and the structure of the metamorphism is indicated by the steepened dips in the folia adjacent to dikes. Also, numerous thin stringers of aplite in the augen gneiss are more like the dike rocks than the metamorphic rocks. The aplitic rocks are most- ly potassium feldspar (as much as 60 percent) and quartz with only a little plagioclase and biotite. Part of the metamorphism seems to be later than the thrust faulting. Locally, there has been reaction be- tween the gneiss and the granitic rock, suggesting local assimilation. Augen locally are collected in pegmatitic EXPLANATION Qg Fan gravel Waxes Granite Pore bacs oon re Hidden Valley and Ely Springs Dolomites, Eureka Quartzite, and Pogonip Group wood eco bower xx Nopah, Bonanza King, Carrara, and Wood Canyon Formations Stirling Quartzite and Johnnie Formation gs ¥ H if M 3 ex wa Contact High-angle normal fault Dotted where concealed A_A_A_ A A_ A_ A. Thrust fault Sawteeth on upper plate 3s Strike and dip of beds FicurE 96.-Map of Amargosa thrust complex along the east foot of the Panamint Range. Felsitic rocks Dikes and sills, mostly felsite; some basalt y- TERTIARY A X ear N ae Mares 2 MILES QUATERNARY SILURIAN DEVONIAN PRECAMBRIAN - CAMBRIAN(?) ORDOVICIAN, AND CAMBRIAN STRATIGRAPHY AND STRUCTURE * A131 FicurE 97.-View of dike swarm in Amargosa thrust complex. At this location, the mouth of Death Valley Canyon, the host rock is a granitic intrusion. or aplitic masses that seem to provide a gradation be- tween the gneiss and some of the felsitic dikes that cut the gneiss. Also, the trace elements in these rocks are similar (table 26). Other evidence indicating metamorphism attributable to the igneous activity is the occurrence of incompletely replaced metasediments in the granitic rocks (fig. 102). Some of the granite and some of the other igneous rocks may have been similarly generated from older rocks along the thrust fault. In short, the concentration of augen gneiss, granite, felsite dikes, and volcanics, to- gether with various kinds of metasediments and partly granitized rocks along the Amargosa thrust, suggests that the fault zone is an old structure which repeatedly A132 FieurE 98.-View of chaoslike formation in Amargosa thrust complex. having interlayered slabs of Paleozoic dolomite (dark rock in center and foreground). has been the site of mylonitization, recrystalliaztion, igneous invasion, metamorphism and granitization, and perhaps of magma generation. Brecciation of the metamorphic rocks at the Amar- gosa thrust shows that the metamorphism in part at least antedates the thrust, yet this brecciation could partly be due to renewed movement on the thrust. Prob- ably much of the metamorphism is Precambrian, but part of it may be much younger. Ralph L. Erickson (written commun., 1961) found two kinds of zircons in the Amargosa complex (fig. 103). GENERAL GEOLOGY OF DEATH VALLEY, CALIFORNIA The formation consists mostly of volcanic rocks (light colored) Location is north side of Death Valley Canyon. Zircons from the augen gneiss are colorless, rounded, and frosted ; zircons from the granite and volcanic rocks are brown- ish, pink, euhedral, and somewhat larger. Zircons from the biotite gneiss are mixed, but the colo. riety predominates strongly. Zircons in the aplite are the e 5 20 1, 000 70 200 5 15 150 30 1 7, 000 70 15 10 10 700 300 1. 5 <10 1, 000 30 150 10 20 100 30 1 7, 000 70 15 15 20 1, 000 500 2 20 1, 500 5 150 <5 10 150 20 |<1 10, 000 50 15 10 | <10 1, 500 700 2 30 1, 000 70 700 300 30 150 15 5 20, 000 150 | <10 15 300 | 10, 000 |1, 500 |>5 DEATH VALLEY CANYON TO TUCKI WASH Felsitic rocks 30 100 5 700 10