The Frontal Structure of the Musconetcong Nappe System sult meas in Eastern Pennsylvama and New ersey _. j GEOLOGICAL survEy PROFESSIONAL PAPER 1623fo— The Lyon Station-Paulins Kill Nappe- The Frontal Structure of the Musconetcong Nappe System in Eastern Pennsylvania and New Jersey By AVERY ALA DRAKE, JK. GEO EOGIC AI SURVEY PROFESSLONAL-PAXPGLR 192 3 A study of a complex nappe system in the complicated polydeformed terrane of the central Appalachians UNITED. STAXTES GOVERNMENT PRINTING OFFICE,: WASHING TON : 1978 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard, Director Library of Congress Cataloging in Publication Data Drake, Avery Ala, 1927- The Lyon Station-Paulins Kill nappe. (Geological Survey professional paper ; 1023) Bibliography : p. Supt. of Does. no.: I 19.16:1023 1. Nappes (Geology) -Pennsylvania. 2. Nappes (Geology) -New Jersey. I. Title. II. Series: United States. Geological Survey. Professional paper ; 1023. QE606.5.U6DT7 551.8'7 76-608376 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-03104-3 PLATE FIGURE TABLE L pF p ;o F 1, CONTENTS Page =4- cw -. as anl ean bal ws ables an swe must a anes a nees 1 s 2 -..... .. . .. L2 lous un nu cl Ll Lil Le en Eel ie cna e 18 summary 'and conclusions . .S 10 L2 L__L. r...... X. 19 References CIRA - 2 ns . o oen 2 non nan naan ie nae nene alee ae eni ne eran namie ee 19 ILLUSTRATIONS [Plates are in pocket| Geologic maps and sections of areas in eastern Pennsylvania and New Jersey. Geologic maps and sections of the Paulins Kill Valley inner windows, New Jersey. Geologic map and sections of areas in the Lehigh Valley, Pennsylvania. Page Map showing the divisions of the Great Valley of Pennsylvania and New Jersey and their relations to adjacent geologic terranes :.. .. ...... .. .. .s .. u. oo ne s onl o n no olo mene ne lanl min nd n ae i o a ar nee ain tale mie a iene aa e guineas ae ae 2 Aeromagnetic map of part of eastern Pennsylvania 4 Photographs showing fabric elements in the Martinsburg Formation _____________________________ 10 Equal-area plot of poles to strain-slip cleavage in the Martinsburg Formation in the Portland quad- TanglQ | "2% . o o a o 2 o ool o olan tile fae oe an aie i ie ae aie aler tiie mn hee a a in aie eee at aa meen an a ie a a a on bee arre bae eae an aioe a s a ged 10 Stereographic projection showing double fabric in Martinsburg Formation 10 Stereographic plot of poles to bedding and small fold axes in bedding in carbonate rocks within the Paulins Iill - Valley: -. .. = 02000. een ennnrentrinkanaes=~aneh aikens es ians ah annees 11 Fabric diagrams of Martinsburg Formation in 1-km strip immediately adjacent to Paulins Kill Valley west of Dela Ware RIVET . _. _. cnl l lola nnn cn ene nea nra nnn ice nan i en aan be wes e 11 Fabric diagrams of Martinsburg Formation in 1-km strip immediately adjacent to Paulins Kill Valley gastiof Dela Ware RIVET. .C 22 -- » o us oh urn ca ee en an banal ain tears a =s aie an nani sen it ae msn nne n 12 Fabric diagrams of Martinsburg Formation in the Portland quadrangle ____________________________ 13 Photographs showing tectonic fabrics in Beekmantown rOCKS 16 Fabric diagrams of carbonate rocks in the southwestern part of the Catasauqua quadrangle ________ 17 TABLE Page Bock units in eastern Pennsylvania and-NMNew L Los tll. 5 III aw - -G sani THE LYON STATION-PAULINS KILL NAPPE- THE FRONTAL STRUCTURE OF THE MUSCONETCONG NAPPE SYSTEM IN EASTERN PENNSYLVANIA AND NEW JERSEY By Avery Aua DRAKE, JR. ABSTRACT Geologic and aeromagnetic data show that a major tectonic unit underlies rocks of the Musconetcong nappe in the Great Valley of eastern Pennsylvania and New Jersey. This struc- ture, the Lyon Station-Paulins Kill nappe, can be traced from Lyon Station, Pa., at least to Branchville, N.J., a dis- tance of about 120 km. The nappe has a core of Precambrian crystalline rocks as shown by an aeromagnetic anomaly that has the same signature as the outcropping Precambrian rocks of the Musconetcong nappe. This core extends at least 70 km east from Lyon Station to Bangor, Pa., the eastern limit of the aeromagnetic survey. Carbonate rocks in the upper limb of the nappe are ex- posed in the Whitehall window and in an unnamed window near Catasauqua, Pa., and in the Paulins Kill Valley of New Jersey, which is a very large window through the Musconet- cong nappe. These carbonate rocks are of a more shoreward facies than the rocks in the Musconetcong nappe, showing that the Lyon Station-Paulins Kill nappe is a frontal as well as tectonically lower structure. The Lyon Station-Paulins Kill nappe has a lower limb, as is proved by three inner windows within the Paulins Kill window in New Jersey. The nappe has no crystalline core this far east. The Lyon Station-Paulins Kill nappe interfaces with the overlying Musconetcong nappe along the major Portland fault. This fault shears upsection through the Musconet- cong nappe, bringing lower-limb rocks of that nappe into contact with the Lyon Station-Paulins Kill nappe in the Whitehall window and bringing upper-limb Musconetcong rocks into contact with the lower nappe in the Paulins Kill window. The Portland fault, though folded, is a late tectonic event and is thought to be a strong imbricate splay from the major décollement that lies just above the basement in the central Appalachians. The Portland fault, therefore, telescoped nappes formed during the Taconic orogeny and was folded with them during the Alleghenian orogeny. Far-traveled tectonic units within eastern Pennsylvania and New Jersey are recognized to belong to the very com- plex Musconetcong nappe system. Near Allentown, Pa., this system consists from lowest to highest, of the Lyon Station Paulins Kill nappe, the Musconetcong nappe (sensu stricto), and the South Mountain nappe. Another structure, the Applebutter thrust sheet, belongs to this system, but its position is unknown. The Musconetcong nappe system is tectonically overlain by the Lebanon Valley nappe system near Reading, Pa., suggesting that all the far-traveled units of these two systems should be included in a Reading Prong nappe megasystem. INTRODUCTION In recent years, a nappe theory has been devised to explain the highly complicated structural rela- tions in the Great Valley and Reading Prong of east-central and eastern Pennsylvania and western New Jersey (fig. 1). Although Stose and Jonas (1935) believed, probably largely intuitively, that the Precambrian rocks of the Reading Prong were in thrust contact with the Paleozoic rocks of the Great Valley, the tectonic concept of far-traveled rocks for this region was not accepted by most geologists. Carlyle Gray and his coworkers of the Pennsylvania Geological Survey (Gray, 1951, 1952, 1959; Field Conf. Pa. Geologists, 1954; Gray and others, 1958; Geyer and others, 1958, 1963) first conceived the relations to be those of a grand Alpine-type nappe in the Lebanon Valley of Lebanon and western Berks Counties, Pa. Their concept has more recently been elaborated and re- fined by MacLachlan (1964, 1967; MacLachlan and others, 1976; Field Conf. Pa. Geologists, 1966), who also found that in the Harrisburg area, rocks of the Lebanon Valley nappe tectonically overlie autochthonous rocks (Cumberland Valley sequence) that are of similar age but somewhat different fa- cies. This nappe includes all carbonate rocks of Cambrian and Ordovician age of the Lebanon Valley sequence and an indefinite part of the Martinsburg Formation of that sequence. In 1957, the U.S. Geological Survey began a sys- tematic study of the geology of the Delaware Val- ley. Large overturned and recumbent folds were soon recognized in the Great Valley and within in- termontane valleys of the Reading Prong (Drake 77° 4/0 & & 33 b> gy2 4 \ %o ' BLUE MOUNTAIN Stroudsburg STRUCTURAL FRONT CUMBERLAND VALLEY , south ‘ , HARRISBURG PAULINS Kil MOUNTAIN w VALLEY LEHIGH VALLEY s Lep . dey Yau, 7 . s ; P - e C 770 25 50 75 100 KILOMETERS | g: py zag > /> 1 | | Erins | | [ 0 25 50 75 100 MILES FIGURE 1.-Map showing the divisions of the Great Valley of Pennsylvania and New Jersey and their relations to adjacent geologic terranes. Cambrian and Ordovician rocks of the Great Valley (light shading); Precambrian rocks of the Reading Prong and South Mountain anticlinorium (stippled) ; Silurian and younger Paleozoic rocks (unshaded); Triassic rocks of the Newark Basin (dark shading); and Precambrian and lower Paleozoic rocks of the Appalachian Piedmont (ruled pattern). C AHMHSYHL MHN UNV VINVATASNNHId NHNMLSVH 'H4IVN TIIXM SNIIAYVI-NOLLYVILS NOXAT INTRODUCTION 3 and others, 1960). In addition, we found that thrust faults and overturned folds were more of a factor in the distribution of the Precambrian rocks of the Reading Prong than had been supposed previously and that some Precambrian bodies were probably klippen (Field Conf. Pa. Geologists, 1961). Con- tinued studies culminated in the interpretation that in the Delaware Valley, Precambrian rocks of the Reading Prong and Paleozoic rocks of the Great Valley are all involved in one grand nappe de re- couvrement (Drake, in U.S. Geol. Survey, 1966; Drake, 1967a, 1967b, 1969, 1970). This structure was called the Musconetcong nappe and was visu- alized as embracing all lower Paleozoic rocks up to and including the Martinsburg Formation and, in addition, the Precambrian rocks that formed the core. In addition to the regional nappes described above, Sherwood (1964; Field Conf. Pa. Geologists, 1961) in a topical study of the Jacksonburg Lime- stone in Northampton and Lehigh Counties, Pa., delineated a large recumbent fold, which he called the Northampton nappe. More recent work has shown that this nappe is the hinge zone of the re- gional Musconetcong nappe. The obvious question, therefore, is, what is the relation of the Lebanon Valley nappe to the Mus- conetcong nappe? Originally, both MacLachlan (oral commun., 1968) and I (Drake, 1969) believed that both our areas were on the same essential structure. At that time, however, no intervening country had been mapped, and in tectonically com- plicated terrane such as this, anything is possible except a simple solution. Continued mapping to the east by MacLachlan (MacLachlan and others, 1976) and to the west by me has shown, not too surprisingly, that both the Lebanon Valley and Musconetcong nappes are ac- tually nappe systems, each consisting of several individual structural elements. Two pieces of evidence suggested to me (Drake, in U.S. Geol. Survey, 1969, p. A28) that another nappe of regional extent lies tectonically beneath the Musconetcong nappe in the Lehigh Valley of eastern Pennsylvania and the Kittatinny Valley of New Jersey. The first piece of evidence is a large subsurface aeromagnetic anomaly at a depth of about 1.6 km, centered near Catasauqua, Pa. (fig. 2). This anomaly can be traced northeastward from Lyon Station, Pa., where it emerges from beneath the outcropping Precambrian rocks of the Reading Prong, to the northeast limit of the aeromagnetic survey near Bangor, Pa. The anomaly is like those caused by the outcropping rocks of the Reading Prong, and it seems clear that it is caused by simi- lar rocks. Directly on strike with the anomaly in New Jersey is the carbonate-rock-floored Paulins Kill Valley, which is surrounded by clastic rocks of the Martinsburg Formation (pl. 14). The valley is antiformal, and stratigraphic relations within the carbonate rocks suggest that they are right side up and anticlinal (the Ackerman anticline), but they are bounded on all sides by the Portland fault, a younger-over-older thrust (Drake and others, 1969) . Further reconnaissance in New Jersey turned up lenticular masses of Jacksonburg Limestone (Mid- dle Ordovician) and Epler Formation (upper Lower Ordovician) within Allentown Dolomite (Upper Cambrian) along the axial trace of the Ackerman anticline (Drake, in U.S. Geol. Survey, 1971, p. A27). These rocks are severely deformed, and are physically beneath the older Allentown Dolomite. These relations suggest that the rocks have been recumbently folded and that the lower limb has been exposed by later arching and faulting. The Ackerman anticline in the Portland quadrangle (Drake and others, 1969), therefore, is not the rela- tively simple structure it appears; it rather re- flects the arching of the upper limb of the above- defined recumbent fold. The probable Precambrian rocks causing the aeromagnetic anomaly between Bangor and Lyon Station, Pa., were probably from a crystalline core to this recumbent fold, which has been called the Lyon Station-Paulins Kill nappe (Drake, in U.S. Geol. Survey, 1971, p. A72). It is apparent that the Precambrian rock core of this structure defined by the aeromagnetic anomaly to the west is not present in this part of New Jersey, and that the entire Paulins Kill Valley is a large window. Later detailed mapping in the Catasauqua, Pa., area delineated two areas of outcrop of strati- graphically right-side-up Allentown Dolomite with- in a terrane of generally inverted Epler Forma- tion (Drake, in U.S. Geol. Survey, 1972, p. A25). The Allentown is in fault contact with the surround- ing rocks, which are in the lower limb of the Mus- conetcong nappe; it must, therefore, belong to the subjacent Lyon Station-Paulins Kill nappe showing through windows similar to the large Paulins Kill Valley window. The Lyon Station-Paulins Kill nappe is obviously a major tectonic element in eastern Pennsylvania and New Jersey. The purpose of this paper is to define this frontal and tectonically lowest nappe of the Musconetcong system. This is done by more 4 LYON STATION-PAULINS KILL NAPPE, EASTERN PENNSYLVANIA AND NEW JERSEY continued from above $ $ ow on.) K I S # - coe \\ © New Smithville tp fiéfi- orthampton ___| %o oC ‘\% p. Kutetown\2 38 0,170" o MonteresgD O\ %\I J OFogelsville es. > z < 9 © \ a Station % ye ; & § cg) 0 £ X O % < \ f Allentowr o £ (=] ) Alburti p o S S 5 'Bethichen cungie / ~3z2 %o $ P. 43:3 % 6 0°25; ”f? ll: angor Columbig p\/ . E rar en." (3°‘\/ Als V—szath e s pn o & x6 0 5 MILES Modified from Bromery and Griscom, 4 --- 1967, and Henderson and 0 5 KILOMETERS others, 1966 EXPLANATION -v- # - ov ~- Inclined Fault \\ C Precambrian rock in core of Musconetcong nappe f @) At places includes superjacent Hardyston Magnetic contours Quartzite of Early Cambrian age Core-cover interface of 6 c a Musconetcong nappe ontour interval 50 gammas. o Hachures show closed areas of lower magnetic intensity FIGURE 2.-Aeromagnetic map of part of eastern Pennsylvania. REGIONAL STRATIGRAPHY 5 fully describing the evidence summarized above. In addition, some regional interpretations pointed out by this study are made. I would like to thank my colleague J. M. Aaron for his work in the Paulins Kill Valley and for his continuing efforts to make me aware of important sedimentological features. Continual prodding by G. H. Wood, Jr., of the U.S. Geological Survey forced me to attempt to relate the Musconetcong nappe system to the major décollement at depth. Free interchange of information through the years with D. B. MacLachlan of the Pennsylvania Geo- logical Survey has been of great help in gaining an understanding of the geology of this highly com- plicated region. REGIONAL STRATIGRAPHY Rocks pertinent to this study include Precambrian gneisses and granitoids and sedimentary rocks of Cambrian and Ordovician age. The pre-upper Mid- dle Ordovician rocks of the Great Valley belong to the orthoquartzite-carbonate facies and were de- posited on the great east-facing bank that was so prominent in the Appalachians at that time. After basin reversal (Zen, 1972), late Middle and lower Upper Ordovician graywacke-shale flysch was de- posited. The stratigraphic sequence for the area discussed herein is given in table 1. The thicknesses given were determined at the best exposures in the Delaware and Lehigh Valleys and almost certainly are not valid for the Paulins Kill Valley. (For a complete discussion of this stratigraphy see Drake, 1969.) In this paper, by necessity, the informal unit Kittatinny carbonate terrane is used for the strati- graphic interval. Leithsville Formation through Beekmantown Group in areas where there has been no detailed mapping. In addition, the Martinsburg Formation is undivided where no mapping data are available. Transported sequences of pelitic rocks have been lumped with the Martinsburg Formation in the arzsa west of the Lehigh River, as their pres- ence has no bearing on the theme of this paper. TABLE 1.-Rock units in eastern Pennsylvania and New Jersey Formation Member Martinsburg Formation (upper Middle and lower Upper Ordo- vician). Pen Argyl Dark-gray to grayish-black, thick- to thin-bedded, evenly bedded slate, rhythmically interlayered with beds of quartzose slate or subgraywacke and carbonaceous slate. Upper contact is unconformable and site of a décolle- Thickness (meters) 1,000-2,000 Description ment. Contains mineral assemblage muscovite-chlorite- albite-quartz. Ramseyburg _____- Medium- to dark-gray slate that alternates with beds of About 930 light- to medium-gray, thin- to thick-bedded graywacke and graywacke siltstone. Graywacke composes 20-30 percent of unit. Upper contact gradational. Pelitic ele- ments contain mineral assemblage muscovite-chlorite- albite-quartz. Bushkill _:-.._._.. Dark- to medium-gray thin-bedded slate containing thin 1,350 beds of quartzose slate, graywacke siltstone, and car- bonaceous slate. Upper contact gradational. Contains Jacksonburg Limestone Cement-rock facies. (Middle Ordovician). mineral assemblage muscovite-chlorite-albite-quartz. Dark-gray, almost black, fine-grained, thin-bedded argil- laceous limestone. Contains beds of crystalline limestone 100-3830 at places. Upper contact gradational. Contains mineral assemblage calcite-chlorite-muscovite-albite-quartz. Cement-limestone facies. Light- to medium-gray, medium- to coarse-grained, large- ly well-bedded calcarenite and fine- to medium-crys- talline high-calcium limestone. Upper contact is grada- 70-130 in main outcrop tional in main outcrop belt but is apparently uncon- belt. formable and marked by a conglomerate in the Paulins Kill lowland. Lower contact is marked by a dolomite pebble to boulder conglomerate in main outcrop belt. Ontelaunee Formation (Lower Ordovician). Medium-dark gray mostly very finely crystalline dolomite. Unit is cherty at the base and contains beds of medium- 0-200 gray calcilutite at the top. Upper contact is sharp and unconformable. Unit is only sporadically present east of Northampton, Pa. Epler Formation (Lower Ordovician). Interbedded very fine grained to cryptogranular, light- to medium-gray limestone and fine- to medium-grained About 270 light-gray to dark-medium-gray dolomite. Upper con- tact sharp and unconformable except where Ontelaunee is present. At those places it is gradational. 6 LYON STATION-PAULINS KILL NAPPE, EASTERN PENNSYLVANIA AND NEW JERSEY TABLE 1.-Rock units in eastern Pennsylvania and New Jersey-Continued Formation Member Description $2253? Rickenbach Dolomite . -- _ Fine- to coarse-grained, light-medium to medium-dark- - About 220 (Lower Ordovician). gray dololutite, dolarenite, and dolorudite. Lower part characteristically thick bedded, upper part generally thin bedded and laminated. Upper contact gradational. Allentown Dolomite | :. * Very fine to medium-grained, light-gray to medium-dark - About 575 (Upper Cambrian). gray, alternating light- and dark-gray weathering, rhythmically bedded dolomite containing abundant algal stromatolites, oolite beds, and scattered beds and lenses of orthoquartzite. Upper contact gradational. Leithsville Formation - .; __________.:l.l._... Interbedded light-medium-gray to dark-gray, fine- to - About 350 (uppermost Lower coarse-grained dolomite and calcitic dolomite, light-gray and Middle Cambrian). to tan phyllite, and very thin beds and stringers of quartz and dolomite sandstone. Upper contact is grada- tional. Phyllite contains mineral assemblage muscovite- chlorite-albite-quartz. Hardyston Quartzite -: - }.... Gray quartzite, feldspathic quartzite, arkose, quartz About 30 (Lower Cambrian). pebble conglomerate, and silty shale or phyllite. Upper contact is gradational. Phyllite contains mineral as- semblage muscovite-chlorite-albite-quartz. Quartzo-feldspathic gneiss, granitoids, and amphibolite. Upper contact sharp and unconformable. Rock has been at hornblende granulite facies and is typically retro- graded to greenschist facies near tectonic contacts. CATASAUQUA AEROMAGNETIC ANOMALY Aeromagnetic mapping of the Allentown, Pa., quadrangle (Bromery and others, 1959) has shown a marked magnetic basement anomaly beneath the Great Valley; this anomaly is centered near Cata- sauqua, Pa. The anomaly can be traced southwest to Lyon Station, Pa., where it emerges from beneath the outcropping Precambrian rocks (fig. 2). To the east and northeast, the anomaly has two prongs. One passes beneath the outcropping Precambrian rocks near the Delaware River; the other extends toward Bath, Pa. (fig. 2). The anomaly at Bangor (fig. 2) is, almost certainly, an extension of the Bath prong, although the association cannot be verified until the intervening area is mapped aeromag- netically. The Catasauqua anomaly was originally inter- preted as being the reflection of a basement arch associated with an anticline in the outcropping Paleozoic rocks, the basement being about 1.6 km deep (Bromery, 1960). More recent analysis (Brom- ery and Griscom, 1967) has shown that the gradient associated with the Catasauqua anomaly does not steepen were it intersects the outcropping Precam- brian rocks; hence, the magnetic rocks producing the anomaly do not change depth. The outcropping Precambrian rocks, therefore, are tectonically above the buried magnetic rocks. Magnetic rocks appar- ently occur at two tectonic levels separated by 1.6 km or so of nonmagnetic Paleozoic rock. The ques- tion that immediately arises is whether the lower level is basement or possibly another allochthonous nappe core or thrust sheet. Lithologic boundaries are reasonably well known in the Catasauqua area (pl. 1B), and modern stra- tigraphic and structural studies have clearly demon- strated regional inversion and the presence of a nappe (Sherwood, 1964; Drake, 1969, and unpub. data). Plate 1B shows no apparent relation between the trace of the anomaly and the mapped geology; in fact, the anomaly cuts across the geologic grain. The anticline mentioned by Bromery (1960) pre- sumably would be cored by the Allentown Dolomite southwest of Catasauqua (pl. 1B). This is not a normal anticline, however, as the Allentown body is bounded on all sides by inverted Epler Formation of the Beekmantown Group, and the contact is a thrust fault. Southwest of Catasauqua, the trace of the anom- aly cuts across the geologic grain at a small angle until it passes beneath the outcropping Precambrian rocks near Lyon Station (pl. 1B). Here the anomaly closes and dies out abruptly with only negative anomalies along strike. This pattern is like that within the Reading Prong where anomalies caused by Precambrian ridges abruptly terminate in nega- tive-anomaly basins as the magnetic rocks spoon out (Drake, 1969, 1970). Bromery and Griscom (1967) noted similar relations west of Reading where the prong spoons out. Regional inversion in the Great Valley is shown by the many tectonic windows along this belt that expose antiforms cored with younger rock (pl. 1B). The Catasauqua anom- PAULINS KILL VALLEY 7. aly, therefore, is not caused by basement. If it were, the anomaly would not die out to the west as it does at Lyon Station. Those who would appeal to a masking effect by the outcropping Precambrian rocks must explain why the supposed basement anomaly is not seen west of the outcropping Pre- cambrian rocks. ¢ Northeast of Catasauqua, the trace of the anomaly makes an angle of about 20° with the grain of the geology (pl. 1B). At Bangor, it is directly on strike with the Paulins Kill Valley in New Jersey (pl. 1A), although, unfortunately, no aeromagnetic data are available farther to the northeast. I have pointed out (Drake, 1969, 1970) that from north-central New Jersey to Reading, Pa., the Read- ing Prong and adjacent Great Valley lie dead center on the regional gravity low. The area considered herein is in the deepest part of the gravity trough at depths of 17 to 20 km. Aeromagnetic surveys in- dicate that basement is deeper than 8.5 km along the Blue Mountain structural front (Blue Mountain décollement of Drake and others, 1969) to the north (Drake, 1969, 1970). In addition, private oil-com- pany seismic surveys (V. E. Gwinn, written com- mun., 1966) indicate that the first basement reflec- tion is at depths of 12 to 17 km just off the front of the outcropping Precambrian rocks near Lyon Station. All these data make it highly unlikely that basement is the cause of the Catasauqua anomaly; therefore, it must be the result of a blind alloch- thonous body. One can be confident that this body is similar to the outcropping Precambrian rocks in the Reading Prong, as they have such a character- istic high-intensity magi c signature. (See Har- wood and Zietz, 1974, for a discussion of the dif- fering magnetic signatures of outcropping Precam- brian rocks in southeastern New York.) The configuration of the anomaly, especially the northeast gradient, suggests that the mag- netic body, most likely a nappe core, has a diving brow (that is, it has been rotated past the horizon- tal) and that it has been arched into an antiform. Negative anomalies along its southeast side suggest that it is not connected with another magnetic body in that direction. The strong magnetic peaks about 6 km east of Catasauqua and probably at Bangor are connected with lesser anomalies by a series of saddles; this pattern suggests that the body causing the anomaly porpoises, that is, plunge culminations and depressions vary its depth. Geologic data pre- sented below reinforce this interpretation. The less well defined southern prong of the anom- aly peak at Catasauqua trends east-northeast past Bethlehem, Pa., toward New Jersey and dies out about at the Delaware River (Henderson and others, 1966). This secondary anomaly probably represents a second arch in the nappe core. Geology at the sur- face supports this interpretation, as the outlying body of Precambrian rock north of Bethlehem (fig. 2 and pl. 1 B) is in a synform. A major antiform about coextensive with the anomaly occurs between the synform and the Precambrian rock of the Read- ing Prong (Drake, 1967a; Aaron, 1975). Harwood and Zietz (1974) have recently de- scribed similar aeromagnetic anomalies from eastern New York and southern New England as resulting from blind bodies of highly magnetic Precambrian rock. They, however, propose a more conservative parautochthonous origin for these bodies in the absence of more firm data on depth to basement. It it interesting to point out that the northeast sub- surface continuation of the Reading Prong makes one of these anomalies that passes under the out- cropping Berkshire massif, much as the Catasauqua anomaly passes under the outcropping Reading Prong. PAULINS KILL VALLEY The Paulins Kill Valley, a lens-shaped lowland about 50 km long within the Martinsburg terrane of the Kittatinny Valley, is underlain by an outlying mass of carbonate rocks of Late Cambrian to Middle Ordovician age (pl. 14). Most of the lowland is in New Jersey, but about 7 km is in Pennsylvania. Bedrock exposures are sparse throughout the valley because of the heavy glacial cover and are particu- larly lacking in Pennsylvania, where there is an abominable thickness of gravel in Jacoby Creek kame field. Most of the lowland has not been studied geologically in any detail. Folio mapping (Bayley and others, 1914) covers only a small part of the valley, and only that part nearest the Delaware River has been mapped at large seale (Drake and others, 1969). This, of course, means that geologic interpretation is difficult, as neither detailed stratig- raphy nor modern structural data are available. STRATIGRAPHY The Allentown Dolomite, Rickenbach Dolomite, Epler Formation, and Jacksonburg Limestone crop out within the Paulins Kill Valley, which is framed by the Bushkill and Ramseyburg Members of the Martinsburg Formation. Most of the basic strati- graphic information on these carbonate units has been gained to the south in the Musconetcong nappe, the reference section for Allentown through Epler 8 LYON STATION-PAULINS KILL NAPPE, EASTERN PENNSYLVANIA AND NEW JERSEY being at Carpentersville, N.J., about 35 km down the Delaware. There are few exposures and no long sec- tions within the part of the Paulins Kill Valley that has been studied in detail. The Allentown Dolomite, however, has more abundant algal stromalite and significantly more oolite and desiccation dolorudite, and much less structureless fine-grained dolomite, suggesting a generally shallower environment than that in which the rocks to the south in the main outcrop belt were deposited. Very little limestone is presented in the Epler Formation, and its absence shows that the dolomitization process has been more complete in this area, again suggesting a generally shallower environment of deposition. The Jacksonburg Limestone differs greatly from that in the main outcrop belt. The type section of this formation is at Jacksonburg, N.J., within the Paulins Kill Valley. Weller (1903) studied this sec- tion in great detail; a trench was dug to expose the formation from its lower contact through a thick- ness of 40 m. At this point, it was impractical to continue trenching, and Weller estimated that prob- ably 5 to 7 m more Jacksonburg was present; thus the total thickness was determined to be about 46- 47 m. Practically all this rock is high-calcium lime- stone. Weller (1903) believed that the lower 20 m of this limestone is of Black River age, the remainder being Trenton in age. R. L. Miller (1937) disagreed with the Black River age but agreed that the lower part of the formation was older (Rockland) than the remainder of the unit, which is younger Trenton ("Hull" and "Sherman Falls") age. He called the older part of the Jacksonburg the Leperditia-bear- ing beds. In the Jacksonburg outcrop belt in New Jersey and eastern Pennsylvania to the Schuylkill River, all authors (Weller, 1908; R. L. Miller, 1937; B. L. Miller and others, 1939, 1941; Sherwood, 1964; Drake, 1965, 1967a, 19676; Drake and others, 1969) have found the Jacksonburg to be far thicker than at the type section (table 1), and though it contains high-calcium limestone (the cement-limestone facies at the base), far more of the formation is argillac- eous limestone (the cement-rock facies). This litho- logic change has been visualized (see for instance Prouty, 1959) as occurring at the Delaware River, the implication being that the eastern Pennsylvania sequence is different from the New Jersey sequence. This view is in error, as the Jacksonburg of the main outcrop belt in the Great Valley of New Jersey and within the intermontane valleys of the Reading Prong is essentially the same as that in Northamp- ton, Lehigh, and eastern Berks Counties, Pa., and not at all like that in the Paulins Kill Valley. More- over, neither Weller (1903) nor R. L. Miller (19837), nor any subsequent worker has found older Leper- ditia-bearing (Black River or Rockland) Jackson- burg outside the Paulins Kill Valley. Most of the described differences between the Jacksonburg at various places within the main out- crop belt are tectonic rather than stratigraphic, as the bulk of the rock in eastern Pennsylvania is in the inverted limb of the Musconetcong nappe and is extremely deformed, whereas much of the rock at and near the Delaware River is in the brow of the Musconetcong nappe and consequently is less severely deformed. Neither Black River nor oldest Trenton (Rockland) fossils have been found in cen- tral or east-central Pennsylvania (Prouty, 1959; Mac Lachlan, 1967). The attempt to relate the rocks west of the Delaware River to the Jacksonburg at the type locality rather than to the rocks east along strike in the main outcrop belt has led to the current difficulties in correlation and nomenclature. R. L. Miller (1937) interpreted the differences in lithology as resulting from a south-to-north grada- tional overlap of the argillaceous limestone facies onto the pure limestone facies in New Jersey, com- bined with a gradual stratigraphic convergence from Pennsylvania into New Jersey. It is certainly true that in the Paulins Kill Valley, presumably nearer shore high-calcium limestone is the dominant facies. The facies difference, however, is between the main Jacksonburg outcrop belt and the Paulins Kill belt. No facies shift was noted in the more than 30-km cross-strike exposure throughout the Reading Prong and Great Valley. I agree with R. L. Miller's (1987) analysis of the sedimentation pattern, but I believe that the present distribution of facies is the result of tectonic telescoping. The Paulins Kill rocks, therefore, are in a separate tec- tonic unit from the rocks outcropping to the south, which are in the Musconetcong nappe. STRUCTURAL GEOLOGY Classically, the Paulins Kill Valley has been con- sidered to be an anticline largely fault-bounded on the south and partly fault-bounded on the north (Behre, 1927, 1933; Lewis and Kiimmel, 1912). The presence or absence of faults apparently was inter- preted by the presence or absence of the Jackson- burg Limestone. The northern faults were con- sidered to be thrusts, and the southern fault was presumed to be a high-angle normal fault (pl. 1 C). Behre (1927, 1933) in his study of the Pennsylvania PAULINS KILL VALLEY 9 slate belt recognized that faults on both the northern and southern borders of the valley had to extend into Pennsylvania. In his mapping, he was faced with the problem of accommodating both sets of faults which had been left dangling in the Martins- burg terrane. In his interpretation, the southern high-angle fault is cut off by the northern thrust faults, which he extended more than 10 km farther into Pennsylvania (Behre, 1927, 1933). The thick gravel in the Jacoby Creek kame field allows almost any interpretation there, but detailed mapping to the southwest in the Stroudsburg and Bangor quadrangles (Epstein, 1973; Davis and others, 1967) clearly shows that Behre's interpretation is not valid and that there is no discontinuity within the Martinsburg terrane that could be the exten- sion of the northern thrust fault. The only logical conclusion, therefore, is that the north and south faults are, in reality, the same fault, which has been called the Portland fault (Drake and others, 1969; Epstein, 1973). This fault has been traced by recon- naissance along both sides of the Paulins Kill Valley. Although complicated by other faults, it closes around the northeast extremity as well, so that the entire lowland is fault-bounded rather than bounded by the hodge-podge of discontinuous faults along the north boundary as is shown by Lewis and Kiim- mel (1912) (see pl. 14). As the north and south faults are one and the same, the nature and type of fault must be deter- mined. The distribution of the carbonate rocks with- in the fault frame suggests an anticline, thereby suggesting that the Portland fault closes upwards over the valley. The concept of far-traveled tectonics within the Great Valley of the central Appalachians, however, necessitates a consideration of the possi- bility that the carbonate rocks of the Paulins Kill Valley are a large klippe, as the tectonic style changes from windows in the lower limb of the Musconetcong nappe in eastern Pennslyvyania to klippen on the upper limb in New Jersey. Numerous klippen of carbonate and Precambrian rock lie on the Martinsburg south of the Paulins Kill Valley between Blairstown, N.J., and Jenny Jump Moun- tain (pl. 14); Jenny Jump Mountain is itself a klippe. If the carbonate rocks in the valley are a klippe, the carbonate rock would have to be in the trough of a large synform in a thrust similar to the synform shown in section B-B' of plate 14 for one of the southern klippen. This core would have to spoon out rather than plunge under at its western extremity; that is, the hinge in the Jacoby Creek area should plunge northeast rather than southwest. The westernmost exposures along the axial trace of the lowland structure are a series of outcrops of Allentown Dolomite just east of the Delaware River, which clearly show that there the structure does plunge northeast, as the beds dip in that direction (pl. 1D). ROCK FABRIC To better evaluate the possibile structural rela- tions, the tectonic fabric of the rocks must be con- sidered. We have known for some time that the rocks in this general area have been deformed at least twice and have a penetrative slaty cleavage and a less pervasive but locally penetrative strain-slip cleavage (fig. 3) (Drake and others, 1960). Slaty cleavage essentially parallels axial surfaces of first folds in bedding, and strain-slip cleavage parallels axial surfaces of folds in cleavage and some second folds in bedding. The strain-slip cleavage strikes about N. 40° E., dips either northwest or southeast (fig. 4), and forms reversed cleavage fans; that is, the fans converge upwards in antiforms and down- wards in synforms. In the southern part of the Port- land quadrangle, the strain-slip fabric is dominant. Some late folds have no cleavage, and we do not know whether they formed contemporaneous with the strain-slip fabric or later. Lineations consist of the intersections of these various planar elements and the axes of minor folds. The strain-slip cleavage and folds in slaty cleavage obviously postdate the penetrative slaty cleavage, as do the second folds in bedding. These two fabrics, as well as related joints, have a regional symmetry over more than 286 sq km (fig. 5). Regionally, the first folds plunge rather gently east-northeast, and the second folds plunge gently southwest, although folds in both sets plunge in opposite directions. A third planar ele- ment S;,(?) is not well understood but is probably cleavage formed during a poorly defined third de- formation (see following paragraphs.) Fabric diagrams have been prepared for the rocks of the Portland quadrangle as well as for several domains within the Paulins Kill Valley and areas immediately adjacent thereto. Data for the carbonate rocks are shown on figure 6. Small folds plunge erratically, but generally northeast; the statistical fold axis, 8, plunges 4° N. 48° E. These data reflect the sample bias resulting from the lack of outcrop west of the Dela- ware River but suggest that the geometry results from the second regional deformation. Fabric data for Martinsburg rocks west of the Delaware River are given in figure 7. Small folds and the statistical fold axis all plunge southwest. 10 LYON STATION-PAULINS KILL NAPPE, EASTERN PENNSYLVANIA AND NEW JERSEY FIGURE 3.-Fabric elements in the Martinsburg Formation. A. Megascopic isoclinal recumbent fold in bedding with axial-surface slaty cleavage. B. Polydeformed slate: Bed- ding dips moderately to the right, relict slaty cleavage is nearly vertical, and penetrative strain-slip cleavage dips moderately left. S FIGURE 4.-Equal-area plot (lower hemisphere) of 40 poles to strain-slip cleavage in the Martinsburg Formation in | FIGURE 5.-Stereographic projection (lower hemisphere) the Portland quadrangle. Contours at 15, 10, and 2.5 per- showing double fabric in Martinsburg Formation (from cent per 1-percent area. Drake, 1969.) PAULINS KILL VALLEY 11 FIGURE 6.-Stereographic plot (lower hemisphere) of 41 poles to bedding (dots) and 11 small fold axes (x) in bedding in carbonate rocks within the Paulins Kill Val- ley. N. 48° E. Certainly the regional plunge is southwest in this area. Two sets of folds are present in bedding, plunging about S. 60° W. (first) and S. 40° W. (second). Fabric data for the Martinsburg Formation east of the Delaware River are given in figure 8. Poles to bedding plot in a complicated crossed girdle. Folds in bedding plunge about N. 55° E. with a secondary maximum at about N. 80° E. Identified second folds in bedding and folds in slaty cleavage plunge about 10° S. 40° W. Although the above re- lations are not completely understood at this time, the data seem to suggest that a third more easterly trending set of folds apparently is present in this area. Poles to bedding for all outcrops of the Martins- burg Formation in the Portland quadrangle, not too surprisingly, plot in a complicated cross girdle (fig. 9). The bulk of the data, however, define a statis- tical axis that plunges about N. 45° E., which is more or less parallel to the second folds in bedding defined in all the domains described above as well as to folds in cleavage and recognized second folds. Most of the small folds in bedding plunge about N. 60° E., with another poorly defined maximum at about N. 80° E. These data suggest that there are 8 FIGURE 7.-Fabric diagrams of Martinsburg Formation in 1-km strip immediately adjacent to Paulins Kill Valley west of Delaware River. A. Stereographic plot (lower hemisphere) of 31 poles to bedding. s=4° S. 49° W. B. Equal-area plot (lower hemisphere) of 28 small fold axes in bedding. Contours at 25, 18, 11, and 4 percent per 1- percent area. 12 LYON STATION-PAULINS KILL NAPPE, EASTERN PENNSYLVANIA AND NEW JERSEY three sets of folds in the area. The same was found true within that part of the Great Valley mapped prior to 1969 (Drake, 1969, p. 105). At that time, the relative ages of the N. 60° E. and N. 80° E. sets of folds were not resolved. A study of the Paulins Kill Valley, however, shows that the N. 60° E. folds are the oldest and the N. 80° E. folds, the youngest, and that a N. 40° E. set intervenes. The configura- tion of the valley is apparently controlled by both the younger fold sets. In any case, it has been shown that the Paulins Kill structure is doubly plunging, and though com- plicated by refolding, the western nose does plunge southwest beneath the Martinsburg cover and is an antiform. This conclusion is supported by the fact that if the carbonate rocks were a klippe, it would require a synform of carbonate rocks to be co- extensive in space with an antiform in the Martins- burg, a possible but unlikely relation. B FIGURE 8.-Fabric diagrams of Martinsburg Formation in 1-km strip immediately adjacent to Paulins Kill Valley east of Delaware River. A. Stereographic plot (lower hemisphere) of 80 poles to bedding. Crossed girdle with B:=6° N. 60° E. and s.=10° S. 56° W. B. Equal-area plot (lower hemisphere) of 77 small fold axes in bedding. Con- tours at 18, 13, 8, and 1.3 percent per 1-percent area. C. Equal-area plot (lower hemisphere) of 13 axes of folds in slaty cleavage and identified second folds in bedding. Contours at 46, 30, and 8 percent per 1-percent area. A PAULINS KILL VALLEY 13 6 2 2 It! jg PORTLAND FAULT So far, I have shown that the Paulins Kill Val- ley is framed by one fault, the Portland fault, and that the carbonate rocks of the lowland and the surrounding Martinsburg are antiformal. The Port- land fault must therefore be folded into the anti- form as well. Field relations (Drake and others, 1969) clearly show that the fault dips north on the north side of the lowland rather than south, as is shown in the older interpretations (pl. 1C). The fault is undoubtedly a thrust fault, as "Christmas tree" style minor folds in both overriding and over- ridden rocks in the north-dipping limb of the fold clearly indicate south-to-north tectonic transport (pl. 1D). Minor folds as well as steps on slicken- sided surfaces clearly indicate south-to-north tec- tonic transport on the fault on the south side of the lowland and prove that it is not a normal fault as previously interpreted. The fault lies at a small € FIGURE 9.-Fabric diagrams of Martinsburg Formation in the Portland quadrangle. A. Stereographic plot (lower hemisphere) of 165 poles to bedding. 8 is about horizontal N. 45° E. with a secondary B at 40° S. 48° W. B. Equal- area plot (lower hemisphere) of 132 small fold axes in bedding. Contours at 25, 20, 15, 10, 5, and 0.7 percent per 1l-percent area. C. Equal-area plot (lower hemisphere) of 35 axes of folds in slaty cleavage and recognized second folds in bedding. Contours at 40, 30, 20, 10, and 3 percent per 1-percent area. 14 LYON STATION-PAULINS KILL NAPPE, EASTERN PENNSYLVANIA AND NEW JERSEY angle to the bedding in the Martinsburg and has moved rocks of the upper limb of the Musconetcong nappe an unknown but large distance north. It is extremely difficult, if not impossible, to determine the amount of transport on a fault that brings younger rocks over older rocks. Total displacement on the Portland fault is thought to be several kilo- meters, although the apparent stratigraphic separa- tions given below mask the true picture. East of the Delaware River, on the south side of the Paulins Kill Valley, the Martinsburg Formation is in contact with the Epler Formation, only two small slices of Jacksonburg Limestone being present (pl. 1D). From a point about 8 km east of the Delaware River, the Portland fault stays at about the same stratigraphic position in the Martinsburg, just above the Bushkill-Ramseyburg contact. Regcon- naissance shows that the Epler Formation is north of the fault as far east as Paulina, N.J. North of Marksboro, N.J., Allentown Dolomite is in con- tact with the Ramseyburg, the entire Beekmantown Group being cut out. Allentown is in contact with Ramseyburg at Swartswood, N.J., east of which I have no stratigraphic information. Jacksonburg slices are more common and larger along the north border of the valley (pl. 14), and so far as is known, only rocks of the Beekmantown Group abut the fault at other places. Both Epler Formation and Rickenbach Dolomite are present on the north side of the valley as a result of the com- plicated internal structure of the carbonate rocks. On the north side of the valley, the fault again lies near the Bushkill-Ramseyburg contact. Westward, toward and across the Delaware River, the Port- land fault cuts down section into the Bushkill Member (pl. 1D). The minimum possible stratigraphic separation on the Portland fault east of the Delaware River is about 1,550 m, as the Ramseyburg is in contact with the Epler Formation. To the east, near Marksboro, N.J., separation is at least 2,050 m, as Ramseyburg is in contact with Allentown Dolomite. The crude knowledge of the geology of the Kittatinny Valley, however, hinders an interpretation of regional re- lations. Lewis and Kiimmel (1912) believe that there is only about 290 m of Martinsburg between the north border of the Paulins Kill Valley and the Shawangunk Formation (pl. 14, section B-B'). Un- fortunately, neither the validity of their structural interpretation nor the thickness of rock missing be- cause of erosion along the Taconic unconformity and faulting on the Blue Mountain décollement can be evaluated at this time. Certainly, much of the Martinsburg Formation is absent from this area. In any case, if the thesis of the paper is accepted, measured separations have little meaning, as the fault is an interface between two entirely different tectonic units. To sum up, the Portland fault is a folded thrust that frames the carbonate rocks in the Paulins Kill Valley; the valley is, then, a very large tectonic window. The fault postdates the F, fabric in the Martinsburg Formation and appears to be deformed by both N. 40° E. and N. 80° E. sets of folds. Most of the regional configuration of the window proba- bly results from the N. 40° E. deformation, but that part from east of Columbia to about Blairstown (pl. 14), appears to be controlled by the N. 80° E. folding. SWARTSWOOD LAKE, STILLWATER, AND WHITE LAKE INNER WINDOWS Other important evidence bearing on the Lyons Station-Paulins Kill nappe is found in the Swarts- wood Lake, Stillwater, and White Lake (formerly White's Pond) areas within the Paulins Kill Valley. At these places, fault-bounded bodies of Jackson- burg Limestone occur within the Kittatinny carbon- ate terrane (pl. 24). These areas of Jacksonburg are all on the crests of upward-closing folds and were considered anticlinal by Kiimmel (1901). Kiimmel's interpretation (pl. 24, part D) is not very convincing tectonically or mechanically ; it requires that a high-angle normal fault form on the crest of an anticline and that the high-angle fault be fol- lowed by back-limb thrusting. All the faults are left to dangle in the Kittatinny terrane, and no rational basis is provided for accommodating them. Instead, a reasonable conclusion might be that the Jackson- burg may have been brought to the surface in anti- forms and, in fact, may belong to the inverted limb of a recumbent structure. Kiimmel's (1901) de- scription of the rocks at these places is consistent with this interpretation, as he found the Jacksonburg to be highly sheared and the fossils therein to be strongly distorted. This tectonite fabric is not pres- ent in the stratigraphically right-side-up Jackson- burg along the Paulins Kill Valley boundary, nor is it the fabric one would expect to form during high-angle faulting. Kiimmel's data (pl. 24, parts A and D) allow a refolded nappe interpretation (pl. 24, part E), if the fault bounding the Jackson- burg body on the south is considered to be a folded thrust that was broken by a later thrust. Recon- naissance in the area (pl. 2B) supports this inter- pretation and shows that rocks of the Epler Forma- tion also crop out within this inner window. WHITEHALL WINDOW That this contact of the Jacksonburg with rocks | of the Kittatinny terrane is tectonic is also shown by | the relations in plate 24, part B, in which a fold hinge of Jacksonburg is bounded on the south by a fault that joins a sedimentary contact around the closure with no displacement, rather than extending into the Kittatinny terrane. The Jacksonburg would appear to be completely fault bounded. Reconnais- sance in the area (pl. 2C) shows that the structure is actually an antiform of Jacksonburg Limestone and Epler Formation bounded on all sides by a folded thrust fault. The structural relations of the Jacksonburg in the White Lake (formerly Whites Pond) area (pl. 2A, part C) would appear to be similar to those in the Swartswood Lake area (pl. 24, part A), but reconnaissance mapping (pl. 2D) clearly shows an antiform of the Jacksonburg and the Epler framed by a folded thrust fault. The dolomite of the Epler has a mylonitic fabric. The above-cited evidence shows that both right- side-up and inverted rocks are exposed within the frame of the Portland fault and that the inverted rocks are exposed in inner windows within the large Paulins Kill window. These data suggest that the Precambrian core of the Lyon Station-Paulins Kill nappe does not extend very far northeast of Bangor, Pa. (pl. 14), and that the structure in the area of the inner windows is only in sedimentary rocks. The simple-appearing Ackerman anticline of the Port- land quadrangle (pl. 1D) is actually a much more complicated fold which deforms both limbs of an earlier recumbent fold. The folds in the thrusts that expose the inner windows probably result from the N. 80° E. deformation. WHITEHALL WINDOW A large body of Allentown Dolomite crops out within the Beekmantown terrane along the Lehigh River south of Catasauqua, Pa. (pl. 1B). This body has been conventionally interpreted as an anticline (Miller and others, 1941), and as mentioned above, this interpretation was originally accepted by Bromery (1960). Until I did detailed mapping in the area, I interpreted the body as a synform similar to those mapped to the east (Drake, 1967a, b) be- cause of the known regional stratigraphic inver- sion in the area. Detailed work showed, however, that the Allentown was right-side-up and anti- formal and surrounded by inverted Epler Forma- tion and Jacksonburg Limestone (pl. 34). Clearly, the Allentown body is completely fault bounded and underlies the surrounding rocks, which belong 15 to the Musconetcong nappe. The fault-bounded body continues on to the west in the Cementon quad- rangle, where mapping has not yet been completed. The Allentown obviously cannot belong to the same tectonic unit that crops out south of the Beekman- town belt. Rocks to the north are also regionally in- verted and in places rotated past the horizontal. These rocks extend for at least 17 km and all belong to the Musconetcong nappe. The body of Jackson- burg Limestone north of the fault-bounded Allen- town Dolomite (pl. 34) is a back interdigitation within the Musconetcong nappe. Here again, as in the Paulins Kill Valley, an anticline of Allentown Dolomite shows through a window, the Whitehall window, in a folded thrust fault. This window is also directly above the crest of the Catasauqua aeromagnetic anomaly (fig. 2), and the Allentown is in the upper limb of the Lyon Station-Paulins Kill nappe. The fault-bounded Allentown east of Catasauqua (pl. 1B) is also in the upper limb of the Lyon Station-Paulins Kill nappe showing through a window. Detailed mapping shows that this body actually includes some Ricken- bach Dolomite and that more of the underlying nappe is exposed. This body is not considered fur- ther in this paper, as a description would be large- ly redundant. I conclude, therefore, that these windows prove the continuity of the structure sug- gested by the Catasauqua aeromagnetic anomaly. ROCK FABRIC Rocks of the Epler Formation and Jacksonburg Limestone that surround the Whitehall window are inverted and severely deformed. The rocks have a tectonite fabric, and in many exposures, bedding has been transposed and thereby is subparallel to the S, cleavage (fig. 10). These rocks in most ex- posures are strongly lineated by a characteristic ruling, which can be seen to result from the inter- section of the subparallel bedding and cleavage. The transposed bedding is folded by later stresses, as is the cleavage and bedding in nontransposed rocks. Three sets of fold axes have been recognized (fig. 11A): N. 80° E. (strongest), generally southwest, and S. 58° E. The axes S. 53° E. are clearly first folds, as they parallel the strong ruling lineation de- scribed above (fig. 11B). The southwest-trending fold axes result from the deformation that pro- duced the prominent folds in cleavage (fig. 11C) in the Jacksonburg Limestone. These folds charac- teristically have axial-surface strain-slip cleavage, and strain-slip fabrics are superposed on transposi- tion fabrics in the more incompetent rocks. 16 LYON STATION-PAULINS KILL NAPPE, EASTERN PENNSYLVANIA AND NEW JERSEY FIGURE 10.-Tectonite fabrics in Beekmantown rocks. A. Dolomite. B. Limestone. Note fold hinge just above coin. The southwest-trending folds are second folds (note the rotated maximum on fig. 114), and the fold axes trending N. 80° E. are the latest recog- nized in this area. These folds quite obviously con- trol the configuration of the frame of the Whitehall window as well as the local geologic grain (pl. 3A). The Allentown Dolomite within the window, in contrast to the framing rocks, is not especially de- formed, except near the fault frame where it is sheared. This fabric is, of course, in keeping with the upper-limb position of the interwindow rocks. The rocks in the Whitehall window area, like those in the Paulins Kill Valley, have been subjected to at least three periods of folding. The trace of the Catasauqua anomaly, which reflects the anti- form in the Lyon Station-Paulins Kill nappe, is controlled by the deformation that produced the southwest-trending fold axes in this area. The con- figuration of the window, however, is controlled by the later N. 80° E. folding. THE FRAMING FAULT The geologic relations of the Musconetcong nappe, the framing fault, and Lyon Station-Paulins Kill nappe at the Whitehall window are shown in plate 3B. These data are from my unpublished maps of the Allentown East and Catasauqua quadrangles, and though somewhat simplified to remove extran- eous detail, are geometrically correct. The rela- tions beneath the framing fault are diagrammatic, yet the Precambrian core of the Lyon Station- Paulins Kill nappe is obviously much closer to the surface than was determined geophysically by - Bromery (1960). No geologic data are available to support a more complicated configuration than that shown. The thickness of the core is taken as about 600 m. It may be thicker, but it is probably not thinner because of the amplitude of the magnetic anomaly. The major problem at the Whitehall window is which fault forms the frame. This problem is ag- gravated by the divergent trend of the outcropping rocks and the subsurface Lyon Station-Paulins Kill nappe (pl. 1B). As was shown above, the Portland fault frames the Paulins Kill window. It is by no means certain, however, that the frame of the Whitehall window is the Portland fault, although this fault is the most likely candidate because it is at the same position relative to the Lyon Station- Paulins Kill nappe in both windows. Aside from the Portland fault, only one other thrust fault of regional importance has been recog- nized in the Delaware and Lehigh Valleys. This fault, the Stockertown fault, is largely blind, but it has been mapped in three quadrangles, where it frames three antiformal windows near Nazareth, Pa. (pl. 1B). Although imbricate splays from the fault have been mapped in the Bangor and Wind Gap quadrangles (Davis and others, 1967; J. B. Epstein, unpub. data, 1976), the fault itself has not been recognized in outcrop other than around win- dows. Especially severe deformation near Manunka Chunk, N.J. (Drake, 1969), suggests that a major fault comes to the surface there, but no such structure could be traced to the west by detailed mapping. However, the fault could easily "hide" within the Martinsburg terrane, especially where glacial deposits are thick. The Stockertown fault can be traced west of the Lehigh River in tectonic windows and intermittent thrust contacts between WHITEHALL WINDOW 17 € FIGURE 11.-Fabric diagrams of carbonate rocks in the southwestern part of the Catasauqua quadrangle. A. Equal-area plot (lower hemisphere) of 85 small fold axes in bedding. Contours at 10, 7.5, 5, 2.5, and 1.5 percent per 1-percent area. B. Equal-area plot (lower hemisphere) of 50 ruling lineations. Contours at 22, 17, 11, 6, and 2 per- cent per 1-percent area. C. Equal-area plot (lower hemis- phere) of 22 folds in cleavage in Jacksonburg Limestone. N Contours at 18, 14, 9, and 5 percent per 1-percent area. carbonate and Martinsburg terranes (pl. 1B). The possibility that the Stockertown fault bounded the Whitehall window has been considered, but available data suggest that this is not the case. The Stocker- town fault, whenever known, lies along the Jackson- burg-Martinsburg contact in the brow and lower limb of the Musconetcong nappe (pl. 2C). Much of the northwestward transport of that nappe is be- lieved to have taken place along this fault, on which the displacement shown on plate 3C is rather se- verely underestimated. If the above interpretation is correct, the Stockertown fault is related to Musconet- cong nappe emplacement; I consider it unlikely that the fault is the interface between two major nappes. When all the available data are considered, one is forced to the conclusion that the fault bounding the Whitehall window is indeed the Portland fault. If this conclusion is correct, then the Portland fault must shear upsection from the inverted limb of the Musconetcong nappe in the Lehigh Valley to the <- 18 LYON STATION-PAULINS KILL NAPPE, EASTERN PENNSYLVANIA AND NEW JERSEY upper limb in the Paulins Kill Valley. That the Port- land fault does shear upsection is proved in Paulins Kill Valley, where it passes from the Bushkill Mem- ber to the Ramseyburg Member of the Martinsburg Formation (pl. 1D). The Portland fault, therefore, is clearly a post-Musconetcong nappe feature that superposes different parts of the structure on the Lyon Station-Paulins Kill nappe. If the fault fram- ing the Whitehall window is not the Portland fault, no interpretation can be made by using currently available data. REGIONAL STRUCTURAL RELATIONS Because the Stockertown fault lies along the Jack- sonburg-Martinsburg contact in the brow and in- verted limb of the Musconetcong nappe, it is tec- tonically above the Portland fault and must be cut off by it at depth in the general area of the Whitehall window. Such an arrangement is dia- grammed in plate 3D, which is a reinterpretation and modification of a section drawn by Sherwood (1964) for an area west of that part of the White- hall window shown in plate 3B. In the construction of this section, the geology beneath the Portland fault was diagrammed as in plate 3B. Jacksonburg Limestone is shown to be absent beneath the Stock- ertown fault, as it is largely absent immediately to the west in both outcrop and in tectonic windows that show Martinsburg Formation through rocks of the Beekmantown Group (pl. 1B). Slices of Jack- sonburg undoubtedly are present beneath the fault at places, however, as this formation is exposed in discontinuous bodies farther west in the Lehigh Valley (pl. 1B). One or more thrust faults are al- most certainly present in the lower limb of the Lyon Station-Paulins Kill nappe, but as no data are avail- able to establish their position, they are not shown in plate 3D. STRUCTURES AT DEPTH The structure at depth greater than that shown in plate 3D is anybody's guess. If one accepts any- thing approaching the minimum geophysical depth to basement, about 12 km, along the front of the Reading Prong, the structure must be exceedingly complicated, presumably something like that shown by Gray and others (1960, section A-B). The struc- tures beneath the Lyon Station-Paulins Kill nappe almost certainly must be confined to the lower Pale- ozoic sedimentary rocks, as there are no aeromag- netic anomalies suggesting possible Precambrian rock involvement in such structures. No factual data are available on the behavior of the Portland fault at depth. It has been shown to be a late tectonic feature that cuts across stratigraphic units within the Musconetcong nappe. No Musconet- cong rocks have been recognized beneath the Port- land fault, so they must be at depth and to the southeast. The Portland fault clearly is a major fault and must be considered a major Alleghenian structure in the Lehigh Valley. This is probably a strong imbricate fault from the major décollement known to occur above the basement interface in the central Appalachians (Gwinn, 1964, 1970; Wood and Bergin, 1970; Root, 1970, 1973). If this inter- pretation is correct, one must consider the possibility that the Stockertown fault is, in turn, an imbricate from the Portland fault. This is doubtful, however, because the Stockertown seems to be so closely re- lated to the recumbent folding. HIGHER TECTONIC UNITS In the Allentown area, the recently recognized (A. A. Drake, Jr., in U.S. Geol. Survey, 1978) South Mountain nappe tectonically overlies the Musconetcong nappe (pl. 3B). The South Mountain nappe is not as yet clearly understood, but it is separated from the Musconetcong nappe by the Black River fault (pls. 1B and 3B). The crystalline core of the Musconetcong nappe consists of the Pre- cambrian rocks east of the trace of this fault (pl. 1B), the nappe being represented only by sedimen- tary rocks in the Allentown area. The Precambrian rocks cropping out in South Mountain and along strike to the west are in the core of the South Moun- tain nappe. This structure might be the same as the one called the Irish Mountain nappe in the Reading area by MacLachlan and others (1976), but this has not been tested in the field. The position of the interface between the sedimentary rocks of the Musconetcong and South Mountain nappes, that is, the Black River fault, is not known very far west of the west boundary of the Allentown East quad- rangle (pl. 1B). Problems such as this await fur- ther fieldwork. At least one other tectonic unit is known in the Allentown area. This unit, a thrust sheet of Pre- cambrian rock, the Applebutter thrust sheet (A. A. Drake, Jr., in U.S. Geol. Survey 1973), crops out in the Saucon Valley (fig. 1). This thrust sheet and the carbonate rocks beneath it are separated from the South Mountain nappe by a steep major fault, and the relative positions of the two tectonic units are not as yet completely understood. In any case, there is a stack of three nappes in the Allentown REFERENCES CITED 19 area. From lowest to highest, these are the Lyon Station-Paulins Kill, Musconetcong, and South Mountain nappes. SUMMARY AND CONCLUSIONS Geologic and aeromagnetic data show that a major tectonic unit underlies the Musconetcong nappe in the Great Valley of eastern Pennsylvania and New Jersey from Lyon Station, Pa., at least as far as Branchville, N.J., a distance of about 120 km. This structure, the Lyon Station-Paulins Kill nappe, is mostly blind in Pennsylvania but is ex- posed in the Whitehall window and another un- named window and is well exposed in a large window in the Paulins Kill Valley of New Jersey. The nappe has a highly magnetic core of Precambrian rock from its western terminus near Lyon Station, Pa., at least to Bangor, Pa., the eastern limit of aero- magnetic surveying, a distance of about 70 km. The core porpoises on plunge culminations and depres- sions and appears to be nearer the surface in the Whitehall window than was determined geophysi- cally. The eastern part of the structure does not have a crystalline core, as sedimentary rocks of the lower limb are exposed in three inner windows. The carbonate rocks in the Lyon Station-Paulins Kill nappe are of more shoreward facies than those of the Musconetcong nappe, proving that the former nappe is a frontal as well as a tectonically lower structure. The Lyon Station-Paulins Kill nappe interfaces with the overlying Musconetcong nappe along the Portland fault. This fault shears upsection through the Musconetcong nappe, bringing different parts of that structure into contact with the underlying nappe. The Portland fault is a major structure and is thought to be a strong imbricate splay from the major décollement that lies above the basement in the central Appalachians. The Portland fault is thought to be an Alleghenian structure. If this is correct, nappes of believed Taconic age (Drake, 1969) have been telescoped and folded together dur- ing the Alleghenian orogeny. What was previously thought of as the Musconet- cong nappe is now recognized to be a complex nappe system consisting of, from lowest to highest, the Lyon Station-Paulins Kill nappe, the Musconetcong nappe (sensu stricto), and the South Mountain nappe. A fourth tectonic unit, the Applebutter thrust sheet, belongs to the system, but its position is not clear at present. The Musconetcong nappe system is tectonically overlain by the Lebanon Valley system of nappes near Reading, Pa., so it would perhaps be well to think in terms of a Reading Prong mega- system of nappes. REFERENCES CITED Aaron, J. M., 1975, Geology of the Nazareth quadrangle, Northampton County, Pennsylvania: U.S. Geol. Survey open-file report 75-92, 353 p. Bayley, W. S., Salisbury, R. D., and Kimmel, H. B., 1914, Description of the Raritan quadrangle [New Jersey]: U.S. Geol. Survey Geol. Atlas, Folio 191, 82 p. Behre, C. H., Jr., 1927, Slate in Northampton County, Penn- sylvania: Pennsylvania Geol. Survey, 4th ser., Bull. M 9, 308 p. 1933, Slate in Pennsylvania: Pennsylvania Geol. Sur- vey, 4th ser., Bull. M 16, 400 p. Bromery, R. W., 1960, Preliminary interpretation of aero- magnetic data in the Allentown quadrangle, Pennsyl- vania: U.S. Geol. Survey Prof. Paper 400-B, p. B178- B180. Bromery, R. W., and Griscom, Andrew, 1967, Aeromagnetic and generalized geologic map of southeastern Pennsyl- vania: U.S. Geol. Survey Geophys. Inv. Map GP-577. Bromery, R. W., and others, 1959, Aeromagnetic map of the Allentown quadrangle, Northampton, Lehigh, and Bucks Counties, Pennsylvania: U.S. Geol. Survey Geophys. Inv. Map GP-213. Davis, R. E., Drake, A. A., Jr., and Epstein, J. B., 1967, Geologic map of the Bangor quadrangle, Pennsylvania- New Jersey: U.S. Geol. Survey Geol. Quad. Map GQ- 665. Drake, A. A., Jr., 1965, Carbonate rocks of Cambrian and Ordovician age, Northampton and Bucks Counties, east- ern Pennsylvania, and Warren and Hunterdon Counties, western New Jersey: U.S. Geol. Survey Bull. 1194-L, 7 p. --- 1967a, Geologic map of the Easton quadrangle, New Jersey-Pennsylvania: U.S. Geol. Survey Geol. Quad. Map GQ-594. 1967b, Geologic map of the Bloomsbury quadrangle, New Jersey: U.S. Geol. Survey Geol. Quad. Map GQ- 595. ----1969, Precambrian and lower Paleozoic geology of the Delaware Valley, New Jersey-Pennsylvania, in Subitzky, Seymour, ed., Geology of selected areas in New Jersey and eastern Pennsylvania and guidebook of ex- cursions: New Brunswick, N.J., Rutgers Univ. Press, p. 51-131. --- 1970, Structural geology of the Reading Prong, in Fisher, G. W., and others, eds., Studies of Appalachian geology-central and southern: New York, Interscience Publishers, p. 271-291. Drake, A. A., Jr., Davis, R. E., and Alvord, D. C., 1960, Taconic and post-Taconic folds in eastern Pennsylvania and western New Jersey: U.S. Geol. Survey Prof. Paper 400-B, p. B180-B181. Drake, A. A., Jr., Epstein, J. B., and Aaron, J. M., 1969, Geologic map and sections of parts of the Portland and Belvidere quadrangles, New Jersey-Pennsylvania: U.S. Geol. Survey Misc. Geol. Inv. Map I-522. Epstein, J. B., 1973, Geologic map of the Stroudsburg quad- rangle, Pennsylvania-New Jersey: U.S. Geol. Survey Geol. Quad. Map GQ-1047. 20 LYON STATION-PAULINS KILL NAPPE, EASTERN PENNSYLVANIA AND NEW JERSEY Field Conference of Pennsylvania Geologists, 20th, Hershey, 1954, Structure and stratigraphy of Lebanon County, by Carlyle Gray, C. E. Prouty, and J. R. Moseley: Harrisburg, Pa., Pennsylvania Geol. Survey, 44 p. Field Conference of Pennsylvania Geologists, 26th, Beth- lehem, 1961, Structure and stratigraphy of the Reading Hills and Lehigh Valley in Northampton and Lehigh Counties, Pennsylvania. Edited by J. Donald Ryan: Bethlehem, Pa., Lehigh Univ., 82 p. Field Conference of Pennsylvania Geologists, 31st, Harris- burg, 1966, Comparative tectonics and stratigraphy of the Cumberland and Lebanon Valleys, by D. B. Mac- Lachlan and S. I. Root: Harrisburg, Pa., Pennsylvania Geol. Survey, 90 p. Geyer, A. R., and others, 1958, Geologic map of the Lebanon quadrangle, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Atlas 167C. 1963, Geology of the Womelsdorf quadrangle, Penn- sylvania: Pennsylvania Geol. Survey, 4th ser., Atlas 177C. Gray, Carlyle, 1951, Preliminary report on certain limestones and dolomites of Berks County, Pennsylvania: Penn- sylvania Geol. Survey, 4th ser., Prog. Rept. 136, 85 p. 1952, The high calcium limestones of the Annville belt in Lebanon and Berks Counties, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Prog. Rept. 140, 17 p. 1959, Nappe structures in Pennsylvania [abs.]: Geol. Soc. America Bull., v. 70, no. 12, pt. 2, p. 1611. Gray, Carlyle, Geyer, A. R., and McLaughlin, D. B., 1958, Geologic map of the Richland quadrangle, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Atlas 167D. Gray, Carlyle, and others, 1960, Geologic map of Pennsyl- vania: Harrisburg, Pennsylvania Geol. Survey, 4th ser., scale 1 : 250,000. Gwinn, V. E., 1964, Thin-skinned tectonics in the Plateau and northwestern Valley and Ridge provinces of the central Appalachians: Geol. Soc. America Bull., v. 75, no. 9, p. 863-900. 1970, Kinematic patterns and estimates of lateral shortening, Valley and Ridge and Great Valley pro- vinces, central Appalachians, south-central Pennsyl- vania, in Fisher, G. W., and others, eds., Studies of Appalachian geology-central and southern: New York, Interscience Publishers, p. 127-146. Harwood, D. S., and Zietz, Isidore, 1974, Configuration of Precambrian rocks in southeastern New York and adja- cent New England from aeromagnetic data: Geol. Soc. America Bull., v. 85, no. 2, p. 181-188. Henderson, J. R., Andreasen, G. E., and Petty, A. J., 1966, Aeromagnetic map of northern New Jersey and adjacent parts of New York and Pennsylvania: U.S. Geol. Sur- vey Geophys. Inv. Map GP-562. Kimmel, H. B., 1901, Report on the Portland cement in- dustry: New Jersey Geol. Survey Ann. Rept. 1900, p. 9-101. Lewis, J. V., and Kimmel, H. B., 1912, Geologic map of New Jersey, 1910-12: New Jersey Dept. Conserv. and Develop., Atlas Sheet no. 40, revised 1931 by H. B. Kiimmel and 1950 by M. E. Johnson. MacLachlan, D. B., 1964, Major nappe in the Susquehanna River (Pennsylvania) region of the Great Valley [abs.]: Geol. Soc. America Spec. Paper 82, p. 126. --- 1967, Structure and stratigraphy of the limestones and dolomites of Dauphin County, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Bull. G 44, 168 p. MacLachlan, D. B., Buckwalter, T. V., and McLaughlin, D. B., 1976, Geology and mineral resources of the Sink- ing Spring 7%-minute quadrangle, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Atlas 177d. Miller, B. L., and others, 1939, Northampton County, Penn- sylvania: Pennsylvania Geol. Survey, 4th ser., Bull. C48, 496 p. --- 1941, Lehigh County, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Bull. C39, 492 p. Miller, R. L., 1937, Stratigraphy of the Jacksonburg Lime- stone: Geol. Soc. America Bull., v. 48, no. 11, p. 1687- 1718. Prouty, C. E., 1958, The Annville, Myerstown, and Hershey Formations of Pennsylvania: Pennsylvania Geol. Sur- vey, 4th ser., Bull. G 31, 47 p. Root, S. I., 1970, Structure of the northern terminus of the Blue Ridge in Pennsylvania: Geol. Soc. America Bull., v. 81, no. 3, p. 815-8830. £ --- 1973, Structure, basin development, and tectogenesis in the Pennsylvania portion of the folded Appalachians, in Jong, K. A. de, and Scholten, Robert, eds., Gravity and tectonics: New York, Interscience Publishers, p. 343-360. Sherwood, W. C., 1964, Structure of the Jacksonburg For- mation in Northampton and Lehigh Counties, Penn- sylvania: Pennsylvania Geol. Survey, 4th ser., Bull. G 45, 64 p. Stose, G. W., and Jonas, A. I., 1935, Highlands near Read- ing, Pennsylvania, an erosion remnant of a great over- thrust sheet: Geol. Soc. America Bull., v. 46, no. 5, p. 757-779. U.S. Geological Survey, 1966, Geological Survey research 1966: U.S. Geol. Survey Prof. Paper 550-A, 385 p. e 1969, Geological Survey research 1969: U.S. Geol. Survey Prof. Paper 650-A, 425 p. 1971, Geological Survey research 1971: U.S. Geol. Survey Prof. Paper 750-A, 418 p. --- 1972, Geological Survey research 1972: U.S. Geol. Survey Prof. Paper 800-A, 320 p. 1973, Geological Survey research 1973: U.S. Geol. Survey Prof. Paper 850, 366 p. Weller, Stuart, 1903, Report on paleontology, V. III, The Paleozoic faunas: New Jersey Geol. Survey, 462 p. Wood, G. H., Jr., and Bergin, M. J., 1970, Structural controls of the Anthracite region, Pennsylvania, in Fisher, G. W., and others, eds., Studies of Appalachian geology- central and southern: New York, Interscience Pub- lishers, p. 147-160. Zen, E-an, 1972, The Taconide zone and the Taconic orogeny in the western part of the northern Appalachian orogen : Geol. Soc. America Spec. Paper 135, 72 p. # U.S. GOVERNMENT PRINTING OFFICE: 1978 O- 261-221/160 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY & _s. s __£ 5 > & ,\V 8 3p» 3» 3p» 75 Modified from Gray and others, 1960 20 KILOMETERS | | J 1 1 15 MILES o -r c Note: 1, approximate line of section of plate 3D; 2, approximate line of section of plate 3C; 3, \ 2 - o t W f " L v o (be c Oe \Q B 0&0 70 < [ )‘¢?0// $ PROFESSIONAL PAPER 1023 A. GEOLOGIC SKETCH MAP AND SECTIONS OF WESTERN NEW JERSEY AND EASTERN PENNSYLVANIA SHOWING PAULINS KILL CARBONATE LOWLAND METERS 600 FEET 2000 300 1000 SEA LEVEL SEA LEVEL METERS 600 300 SEA LEVEL C C! METERS FEET 600 2000 300 1000 SEA LEVEL SEA LEVEL Modified from Behre, 1933 0 5 1 2 $ 4 5 6 KILOMETERS | | tea | | | | | METERS | | I I I l 600 0 Ya 1 2 5 4 MILES 300 SEA LEVEL NOTE: A- A 'at the Delaware River, B- B'near west end of Jacoby Creek Valley, and C-C'at Bangor, Pa. 300 Locations of sections are shown on plate 1A 600 C. GEOLOGIC SECTIONS OF THE EASTERNMOST PENNSYLVANIAN SLATE BELT AND PART OE THE PAULINS KILL VALLEY GEOLOGIC MAPS PLATE I E X PL A N A T l -O N (2 $ 'C Quaternary deposits § & ra az vrBzZ $28 A. bos H Silurian and Devonian rocks. undivided / z 8 Z § s < A [ae $ = -i Tuscarora Sandstone(?) D hock a 89 2 2 $ 3 g § Martinsburg Formation sO Om, Martinsburg Formation, undivided Omp, Pen Argyl Member Omr, Ramseyburg Member z Omb, Bushkill Member < E o I> 5 < S 3 C 8 rg S p s G Jacksonburg Limestone § mis 9 9 e & ~] p 6 Beekmantewn Group Ob, Beekmantow1 Group, undivided Oe, Epler Formation 2, g Or, Ricken bach Dolomite Sis Kittatinny S- € carbonate 5 O terrane Allentown Dolomite é "3 re §.» § | $ o 3 5 { TC §82 5 O ~ = 5 (32° 0O Leithsville Formation g 5 € 3 4 3 € 8 Hardyston Quartzite 7 jest 6 («al j g b Precambrian rocks, in places 6 includes Hardyston Quartzite (2 A. Contact Dotted where concealed Fault yo-r-r y "v" Thrust fault Dotted where concealed Approximate trace of Catasauqua aeromagnetic anomaly red: _o Anticline, showing trace of crest line and direction of plunge Dotted where concealed Ig» Modified from Davis and others (1967), D. SIMPLIFIED GEOLOGIC MAP AND sECTIONS OF THE PORTLAND, PA.. AREA INTERIOR-GEOLOGICAL SURVEY, RESTON, VA-1978-G77004 2 3 4 $ 6 KILOMETERS Drake and others (1969), and Epstein (1973) | | | I I | | | 2 3 4 MILES B B' FEET METERS FEET 2000 600 2000 1000 300 1000 AREA OF SEA LEVEL __ SEA LEVEL SEA LEVEL THIS REPORT 1000 300 1000 41° 2000 600 pe 2000 AND SECTIONS OF AREAS IN EASTERN PENNSYLVANIA AND NEW JERSEY UNITED STATES DEPARTMENT OF THE INTERIOR PROFESSIONAL PAPER 1023 GEOLOGICAL SURVEY PLATE 2 Rock concealed by drift __ SWARTSWOOD LAKE | 2 KILOMETERS | 1 MILE 1 KILOMETER I %2 MILE [ _'SW$fl§wbod . J1 KILOMETER + \ 2 KILOMETERS I | ‘ f 2 KILOMETERS 3 KILOMETERS I | % MILE 1 MILE f | 1 Modified from Kummel, 1901 Note: Location of area shown on plate 2 A & 1 MILE Note: A, Swartswood Lake area; B, Stillwater area; C, Marksboro or White Lake area; D, Diagrammatic GEOLOGIC STRIP MAP OF THE PAULINS KILL LAKE AREA section through Swartswood Lake area as interpreted by Kiummel (1901); E, same section as D using i e ere Ae n ta ee o nappe interpretation; 1, area of plate 2B; 2, area of plate 2C; and 3, area of plate 2D €. GEOLOGIC STRIP MAP OF THE MIDDLEVILLE AREA A. GEOLOGIC SKETCH MAPS AND SECTIONS OF THE PAULINS KILL VALLEY E X P LA NA T_ mo N e o o e Thrust fault Dashed where concealed Martinsburg Formation 704——t——— Om, Martinsburg Formation, undivided B. Omr, Ramseyburg Member Anticline Omb, Bushkill Member Showing plunge Teas .> Antiform Showing plunge Middle and Upper Ordovician ORDOVICIAN Jacksonburg Limestone 48 45 30 Inclined Overturned Rotated more Ordovician than 180° Strike and dip of bedding Ball indicates top known from sedimentary structures Ordovician Beekmantown Group l m- 18 €k Oe, Epler Formation ‘D Or, Rickenbach Dolomite Duck Pond Strike and dip of slaty cleavage Kittatinny carbonate terrane TTF" 36 Upper Cambrian CAMBRIAN Strike and dip of strain-slip cleavage Allentown Dolomite -- 50 Inclined Overturned Strike and dip of essentially parallel bedding and slaty cleavage Contact 30 Strike and dip of mylonitic foliation Dashed where concealed 2 KILOMETERS ‘ Sal ¥ 1 MILE Note: Location of area shown on plate 2A D. GEOLOGIC STRIP MAP OF THE WHITE LAKE AREA GEOLOGIC MAPS AND SECTIONS OF THE PAULINS KILL VALLEY INNER WINDOWS, NEW JERSEY INTERIOR-GEOLOGICAL SURVEY, RESTON, VA-1978-G77004 UNITED STATES DEPARTMENT OF THE INTERIOR PROFESSIONAL PAP§5A%g23 GEOLOGICAL SURVEY 19730 2730" E XP L A NA IT L QO N 40°39'30" & S a £s Omb , ‘ l _ s . L METERS ol 3» S yl o") ‘ Wil | 4 00 s a { U 300 1208 3 § G \ Bushkill Member of Martinsburg Formation . , . : 200 * SEA LEVEL SEA LEVEL 100 D E5 32 < ~ EAULT 1 S é 300 -2 _ __ & 3 F % ~. w 1000 <. 3 Jacksonburg Limestone z 400 -|___ __ _ - . ol Oj, Jacksonburg Limestone, undivided 5 a . i Ojr, cement rock facies S ' < # 23 - 00 Ojl, cement limestone facies O & From Davis and others, 1967 not 0 .5 ] 2 3 KILOMETERS | 1 | | | | I I | 0 Ya 1 2 MILES g 8 8 E 38 30" Note: The approximate location of the section is shown on plate 18 = 6 Beekmantown Group Ob, Beekmantown Group, undivided . O0, Ontelaunee Formation l Oe, Epler Formation W Or, Rickenbach Dolomite li C. GEOLOGIC SECTION THROUGH THE SOUTHWESTERN CORNER [0 § a. OF THE BANGOR QUADRANGLE, PA. -N. J. 5 § a. S 3 § G Allentown Dolomite "3 Z, S 94 5 R ~ 3 8 s ® °C ' is £ 3 31 G Leithsville Formation (®) & & 8 3 f y . f 3 Hardyston Quartzite a_ (- 7 tag? pe 0 D a 1 Li A} | SEAAAELTEESESL l a #8 f SFEiTLEVEL , S7 U* | S x ims spools; <>. [ O '~ , \t, 3 a0°37"30 oe a rfl/Wfifiy i ___ me. o oA. No |- ao 8 Mi / qulfl‘rkl" “At-Hwy l $1111" T L ”NH?!” " AM Th" all I (is ( A ) \/ [ A)? S 0 5 1 2 3 KILOMETERS ‘ C0 A foo iA . selon n ooh s - Ry - a f- 1000 ; 9 ' - d Pra &_ ‘fmfik’fflfi Wall | 1 A to i Precambrian rocks m {I | I | | | | | 500 . fig“ 1 ”4&nysz l M ¢ x af i 1500 E A _ _ { I , e" l . 0 Ya 1 2 MILES . 0 . Mg; $433; i??? film?” - ~ ”gm Wi Al- ‘ Wil "l % I _ _ MM r: ( I 3000 1000 3500 Note: 1, Approximate line of part of section of plate 3B - - - Contact // }, "° ( ”WE’W f ml, / i f" I f r $44? o Wwfiwfifmfifiw l 1 a ~. 4000 i fii he . . ? a . : 4500 Thrust fad! . / d I / / I W ‘ ___ lod - I LL. oncealed, barbs on upper plate A. GEOLOGIC MAP OF THE CATASAUQUA AREA, SHOWING THE WHITEHALL WINDOW __/ _ fl ‘ * <2 _ a ous ’ a A > . vf ‘ | 1, - 1 ‘ *+~ afa Y , , ty U / M 0 U a 6000 i s i fi [ ' ‘ ys ,. L e Inclined _ Overturned Rotated more than 180 2000 , ”WM/[124W | rm,“ lf { / ) Lf - l 25,2312 , W fig” hil figfi’“ ‘ 6500 La I ) 1 to A l R 5 al . g D 1% ‘ e A el {i | Strike and dip of beds i T L | I W @ all ase w U “$15 0 U Maggi; 7000 n ; L 1 ul 0 [ U [ Lat “fifigflxvfi: SLL L 7500 Ball indicates top known from sedimentary structures [0 W l male . A U Al t I ( Le op 0s LL I . -- ) wl w/ ill li l dl a j MB ( y- 2500 g sss 0 0 {0 A O I - f | C0 § wo . _ al. . W rll) _ W ) I A {y as. a We gay”? 8500 Bedding and essentially parallel cleavage l i i, (0 P Al ""”."7"§¢7‘*~‘§W¢’/ Is.. i fl o -> ”fiwflffi L M Wa La _ I il ”W filfiffiifigvfif _ 15, L mfifiw 7’p”‘3’£?5‘5 9000 Ruling lineation Based in part on Sherwood (1964, sec. D-D') 0 1000 2000 3000 METERS | fs psf tost { 37 1000 2000 3000 4000 5000 6000 7000 8000 9000 10,000 MILES & -- D. DIAGRAMMATIC GEOLOGIC SECTION, SHOWING RELATION OF THE STOCKERTIOWN FAULT TO IHE PORTLAND FAULT MUSCONETCONG NAPPE COLESVILLE FAULT MmUSsCcOoNETCONG NAPPE sOUTH MOUNTAIN NAPPE FEET SEA LEVEL - 500 METERS k ~ auks, t . ~ Nass o propor, t= 200 , 300 400 500 700 -L / ii B , ~ I / - / I / I - I ‘ " - A- 2500 800 . > ) I » > L m__ 900 1000 1100 1200 , i I I W L I Wi 1 ' 0 [ I L I il e 1300 " ' i I ( - I . a 1 ‘ I A / W L 1 I 7 A i 1s e , ‘ | . e . s i l 0 0 o 4500 &_ ) " A | » mS l i l ) l d | | l . (f T a - _ . p Ll l WW 1100 _ e 1400 -f Lf _ mgéfif Lal ___ _ ( v ___ "s _ m / 1 t W [ z I INTERIOR-GEOLOGICAL SURVEY, RESTON, VA-1978-G77004 1000 2000 3000 METERS 0 | | | | | | I I 1 I I I I I | 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 _ 10,000 FEET Note: Line of section is just east of west borders of the Allentown East and Catasauqua quadrangles, and is approximately located on plate 18. Geologic relations beneath the Portland (?) fault are diagrammatic B. SIMPLIFIED GEOLOGIC SECTION ACROSS THE LEHIGH VALLEY FROM SOUTH MOUNTAIN TO HOKENDAUQUA, PA. GEOLOGIC MAP AND SECTIONS OF AREAS IN THE LEHIGH VALLEY, PENNSYLVANIA General Geology and Mines of the East Tintic Mining District, Utah and Juab Counties, Utah By H. T. MORRIS and T. S. LOVERING With sections on THE GEOLOGY OF THE BURGIN MINE By A. PAUL MOGENSEN, W. M. SHEPARD, H. T. MORRIS, L. I. PERRY, and S. M. SMITH and THE GEOLOGY OF THE TRIXIE MINE By A. PAUL MOGENSEN, H. T. MORRIS, and S. M. SMITH G EO LOGICAL SURVEY PROFESSIONAL PA PER 10 24 A study of the rocks, geologic structures, and mines of a highly productive silver, gold, and base-metal mining district in the east-central Great Basin UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1979 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard, Director Library of Congress Cataloging in Publication Data Morris, Hal Tryon, 1920- General geology and mines of the East Tintic mining district, Utah and Juab Counties, Utah. "With sections on The geology of the Burgin Mine, by A. Paul Mogensen, W. M. Shepard, H. T. Morris, L. I. Perty, and S. M. Smith and The geology of the Trixie Mine, by A. Paul Mogensen, H. T. Morris, and S. M. Smith." (Geological Survey professional paper ; 1024) Bibliography: p. 194-196. 1. Geology-Utah-Utah Co. 2. Geology-Utah-Juab Co. 3. Mines and mineral resources-Utah-Utah Co. 4. Mines and mineral resources-Utah-Juab Co. I. Lovering, Thomas Seward, 1896- II. Title. QE170.U8M67 557.9224 78-606096 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-03159-1 CONTENTS ADSLTACL: : .s... ..... ? Shs Fa sond ria Sak Pn aaa ae a a+ are introduction .::.. ...-... f fada chs nan sas