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The Richmond and Greenwich Slices of the Hamburg Klippe 

In Eastern Pennsylvania Stratigraphy, Sedimentology, 

Structure, and Plate Tectonic Implications

By GARY G. LASH and AVERY ALA DRAKE, JR.

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1312

A stratigraphies sedimentologic, and structural 

stud}/ of a major Taconic-type allochthon in 

the Great Valley of eastern Pennsylvania

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1984
DEPARTMENT OF THE INTERIOR 

WILLIAM P. CLARK, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Library of Congress Cataloging in Publication Data

Lash, Gary George.

The Richmond and Greenwich slices of the Hamburg klippe in Eastern Pennsylvania.

(Geological Survey professional paper ; 1312)

Bibliography: p.

Supt. of Docs, no.: 119.16:1312

1. Nappes (Geology) Pennsylvania Hamburg region. I. Drake, Avery Ala, 1927- . II Title.

III. Series. 

QE606.5.U6L375 1983 551.8'7 83-600340

For sale by the Branch of Distribution, U.S. Geological Survey, 

604 South Pickett Street, Alexandria, VA 22304

Any use of trade names and trademarks in the publication is for descriptive 

purposes only and does not constitute endorsement by the U.S. Geological Survey.
CONTENTS

Page

Abstract................................................................................................ 1

Introduction ........................................................................................ 2

Previous work .................................................................................... 2

Geologic framework .......................................................................... 2

Terminology ....................................................................................... 3

Stratigraphy and sedimentology ............................................... 3

Windsor Township Formation .................................................. 3

Weisenberg Member .............................................................. 3

Switzer Creek Member ............................................................ 6

Dreibelbis Member ................................................................. 7

Miscellaneous units .................................................................. 9

Graywacke petrography ...................................................... 11

Provenance ................................................................................. 12

Age and correlation .................................................................. 13

Environment of deposition .................................................... 15

Page

Stratigraphy and sedimentology Continued 

Virginville Formation ......................................

Sacony Member ..............................................

Onyx Cave Member ......................................

Moselem Member ..........................................

.................................................... 17

.................................................... 17

.................................................... 18

.................................................... 20

Age and correlation .............................................................. 21

Environment of deposition ................................................. 22

Paleogeography ..................................................................... 24

Structure ................................

Rock fabric ........................

Faults ..................................

Style of deformation ........

Plate tectonic implications 

Conclusions ...........................

References cited .................

26

26

27

27

29

35

37

ILLUSTRATIONS

Page

FKJURE 1. Geologic maps of eastern Pennsylvania .......................... ...................................................................................................................... 4

2. Stratigraphic diagram of the Lehigh Valley sequence .............. .................................................................................................. 6

3. Bouma sequence and variations ................................ ........................................................................................................................... 6

4-14. Photographs showing:

4. Contorted beds and faults in siltstone of the Weisenberg Member ................................................................................. 7

5. Sequences of graywacke, siltstone, and mudstone of the Dreibelbis Member ............................................................ 7

6. Groove casts on the sole of a thick graywacke bed ........................ .......... ....................................................................... 8

7. Graywackes with thin pelitic intercalations .......................................................................................................................... 8

8. Flute casts on the sole of a thin Tc _t, turbidite ........................................................................................................................ 8

9. Contorted graywacke beds .......................................................................................................................................................... 9

10. Thick-bedded chert interbedded with red and light green shale and mudstone ......................................................... 9

11. Limestone megaclast ..................................................................................................................................................................... 10

12. Chaotic slump folds in interbedded mudstone and chert .............................................................................................. 10

13. Graywacke megaclast in boulder conglomerate ................................................................................................................. 10

14. Irregularly shaped graywacke megaclast in boulder conglomerate ............................................................................... 11

15. Classification diagram for the graywackes of the Windsor Township Formation .................................................................... 12

16. Triangular plot comparing detrital modes ........................................................................................................................................... 14

17. Correlation diagram for the Lehigh Valley sequence, Jutland klippe, and Windsor Township Formation ........................ 15

18. Depositional model for the Windsor Township Formation ................................................................................................................ 16

19-25. Photographs showing.

19. Ovoid masses of Sacony Member siltstone .............................................................................................................................. 18

20. Peloidal limestone filling channels in black shale and lime mud ...................................................................................... 19

21. Sedimentary boudinage in ribbon limestones ........................................................................................................................ 19

22. Polymict carbonate-clast conglomerate .................................................................................................................................. 19

23. Polymict carbonate-clast conglomerate containing clasts oriented perpendicular to bedding ................................ 20

24. Contorted beds in interlaminated shale and dolostone ................................... .................................................................... 21

25. Moselem Member mudstone and shale ................................................................................................................................... 21

26. Correlation diagram for the Lehigh Valley sequence, the Windsor Township Formation, the Virginville

Formation, and the Jutland klippe .............................................................................................................................................. 22

27. Facies diagram for the Sacony, Onyx Cave, and Moselem Members of the Virginville Formation ........................................ 24

28. Photograph showing soft-sediment folds in ribbon limestones of the Moselem Member ............................................................ 25

29. Plot of soft-sediment fold axes, fold vergence, slip plane, and slip-line orientation of slump folds

in the Moselem Member .................................................................................................................................................................... 25

30. Plot of fold axes, vergence, and slip-line orientation of tectonic folds in the Moselem Member .............................................. 26

ni
IV CONTENTS

Page

31-33. Photographs showing:

31. Large boudin or phacoid in a pelitic matrix ...................... ........................ ........................................ ....................... 28

32. Small graywacke boudin in a pelitic matrix ....... .............................................................................................................. 28

33. Pinch-and-swell structure ........... .............................. . .............................................................. .. ............................ 29

34. Plate tectonic model for the Hamburg klippe ................................................ ................................. ...... ................................... 30

TABLE

 Page

TABLE 1. Modal analyses of graywackes from the Windsor Township Formation ........................................................................................ 13
THE RICHMOND AND GREENWICH SLICES OF THE 

HAMBURG KLIPPE IN EASTERN PENNSYLVANIASTRATIGRAPHY, SEDIMENTOLOGY, STRUCTURE, 

AND PLATE TECTONIC IMPLICATIONS

By GARY G. LASH1 and AVERY ALA DRAKE, JR.

ABSTRACT

Taconic-type klippen, such as those in the northern and maritime Appalachians, are also characteristic of the Taconides of the 

central Appalachians. One such body of rock, the Hamburg klippe, 

anomalous with respect to the age and lithology of its surroundings, 

has long been recognized in the Great Valley of east-central 

Pennsylvania.

The Hamburg klippe is bounded on the southeast by the parautochthonous rocks of the Lehigh Valley sequence of Cambrian and 

Ordovician age. The carbonate rocks of this sequence were deposited 

on the southeast-facing shelf of the North American Continent and, 

with the underlying Proterozoic Y basement, were deformed into 

the Musconetcong nappe system during the Taconic orogeny. Rocks 

of the parautochthonous nappe system were thrust onto the klippe 

during the Alleghanian orogeny. To the north, the klippe is in fault 

contact with both the Shochary Ridge sequence of Ordovician age 

and the Shawangunk Formation of Late Ordovician(?) or younger 

age.

Recent detailed mapping at the eastern end of this klippe, 

between the Schuylkill River and Kutztown in eastern Pennsylvania, has led to the recognition of two stratigraphically and structurally different slices. The lower Greenwich slice consists of rocks 

of the Windsor Township Formation. The Windsor Township is a 

Middle Ordovician flysch sequence that contains various-sized 

bodies of Lower Ordovician chert, deepwater limestone, and variegated shale. The Windsor Township (about 6,215 m thick) consists of 

three members: (1) the Weisenberg (1,740 m thick), a gray-green 

shale unit that contains local conglomerate beds; (2) the Switzer 

Creek (815 m thick), a gray wacke-gray-green shale unit that contains local pebble conglomerate; and (3) the Dreibelbis (3,660 m 

thick), a graywacke-gray-green shale unit. The sedimentology and 

stratigraphy of these rocks suggest that the graywacke units (Dreibelbis and Switzer Creek) were deposited as channel-axis grainflow and turbidite sediments and as interchannel turbidite sediments, whereas rocks of the Weisenberg (the shale unit) were 

deposited as levee and open-fan muds adjacent to the channels. The 

rocks of the Windsor Township Formation were deposited in the 

middle-fan area of a large submarine fan, which had a continental 

source to the southeast. The older lenticular bodies of chert, deepwater limestone, and variegated shale are not restricted to any 

particular member but are found throughout the Windsor Township. These rocks probably were deposited in an abyssal environment that received periodic influxes of terrigenous material. They 

were emplaced later into the younger fan deposits.

The upper Richmond slice contains rocks of the Virginville 

Formation of Late Cambrian and Early Ordovician age. This unit is 

divided into three members: (1) the Sacony (245m thick), consisting

1 Department of Geology. State University of New York College at Fredonia. Fredonia, NY 14063.

of olive-green siltstone and shale; (2) the Onyx Cave (90 m thick), 

consisting of massive to laminated calcarenite, ribbon limestone, 

massive carbonate-clast conglomerate, and interlaminated black 

shale and orange dolostone; and (3) the Moselem (230 m thick), 

consisting of well-cleaved black and green argillite and mudstone 

and lesser proportions of ribbon limestone and carbonate-clast conglomerate. The Onyx Cave conformably overlies the Sacony, and 

both tectonically overlie the Moselem. The sedimentology and stratigraphy of these rocks suggest that (1) they were deposited near the 

base of a northwest-facing slope and (2) the Moselem is a distal 

equivalent of the Onyx Cave and was deposited to the northwest of it. 

We suggest that the rocks of the Virginville were deposited on a 

northwest-dipping slope adjacent to a shallow-water carbonate 

shelf. Subsequent to deposition, northwest-directed thrust faulting 

brought the Sacony and Onyx Cave over the Moselem.

The rocks of the Hamburg klippe record the effects of three 

phases of deformation. Folds related to the first and third phases 

trend east-northeast to east-southeast and, generally speaking, are 

differentiated only where overprinting is recognized. The second 

deformation phase produced folds that trend northeast. Faults 

within the Greenwich and Richmond slices range from steeply to 

moderately dipping upthrusts to subhorizontal thrust faults and 

typically are not well exposed. The contact between the Richmond 

and Greenwich slices is a thrust fault marked by slivers of Greenwich slice rocks tectonically mixed into the lower part of the Richmond slice.

Rocks in the Richmond slice and the parautochthon deformed 

differently than those in the Greenwich slice. The less competent 

rocks of the Richmond slice and surrounding parautochthon contain 

a slaty cleavage that is axially planar to folds formed during the 

first deformation (Di). The rocks of the Greenwich slice generally 

lack this cleavage but exhibit a scaly cleavage or a poorly developed 

fracture cleayage consisting of a group of intersecting fracture 

planes generally subparallel to bedding that formed prior to Di. The 

fabric of these rocks is similar to that of tectonic melanges formed 

by mechanical fragmentation and mixing.

Results obtained in the present study, combined with data from 

other investigations within the Pennsylvania Great Valley, are consistent with a plate tectonic model that involves late Proterozoic 

rifting leading to the development of a marginal basin separating 

the North American craton from a microcontinent to the southeast. 

In Cambrian to early Middle Ordovician time, carbonate shelves 

developed on both the craton and microcontinent. The Virginville 

Formation was deposited on the lower slope adjacent to the shelf of 

the microcontinent. Southeast-dipping subduction of the North 

American craton, as well as any oceanic crust that may have lain to 

the southeast of it, beneath the microcontinent began in late Early 

Ordovician to early Middle Ordovician (Chazyan) time. Subduction 

was accompanied by (1) trench sedimentation of the flyschoid rocks 

of the Windsor Township Formation, (2) off-scraping and gravity
RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

emplacement of the approaching older abyssal sediments, and (3) 

subduction-related deformation of all rocks of the Greenwich slice. 

The marginal basin was essentially closed by late Blackriveran to 

early Rocklandian time. Because the thick, buoyant continental 

crust of North America was unable to subduct beneath the microcontinent, the eastern margin of the North American craton was 

uplifted, exposing the miogeoclinal cover (Black River hiatus). At 

this time, deposition of the Jacksonburg Limestone and Martinsburg 

Formation exogeoclinal sequences began in response to uplift to the 

southeast. Stress continued to build up along the contact of the two 

plates during Rocklandian to Kirkfieldian time. Consequently, 

slices of continental basement from the eastern margin of North 

America were detached along southeasterly dipping ductile shear 

zones and were thrust into the overlying miogeoclinal sediments, 

resulting in the formation of a nappe system. The Richmond slice 

probably was thrust onto the Greenwich slice, and both were superposed on the forming nappe pile at this time of extreme crustal 

convergence. Continued northwest-directed movement of the nappes 

and Hamburg klippe during Shermanian time was followed by 

detachment of the allochthon from the advancing nappe pile and, 

finally, by its emplacement into the developing Martinsburg foredeep to the northwest.

INTRODUCTION

A large klippe consisting of several stacked slices 

is a major tectonic feature of the Taconide zone in the 

northern Appalachians (Zen, 1972). Taconic-type klippen are characteristic also of the Great Valley of the 

central Appalachians in New Jersey and especially 

eastern Pennsylvania (Drake, 1980). The eastern end 

of the largest klippe in Pennsylvania, the Hamburg 

klippe (Stose, 1946), was studied in the Kutztown and 

Hamburg 7%-minute quadrangles and surrounding 

areas (fig. 1).

These quadrangles lie along the northern side of 

the Great Valley of eastern Pennsylvania. There, the 

Great Valley is bounded on the north by quartzites of 

Late Ordovician(?) to Silurian age that hold up Blue 

Mountain of the Appalachian Valley and Ridge. On 

the south, the Great Valley is bounded by the Proterozoic Y rocks of the Reading Prong.

This paper describes, in detail, the stratigraphy, 

sedimentology, and structure of the rocks of the eastern 

end of the Hamburg klippe and speculates on the 

depositional environments and the plate tectonic implications of these rocks.

PREVIOUS WORK

Allochthonous rocks in the Great Valley of Pennsylvania were recognized by Stose (1946, 1950a, b), 

Stose and Jonas (1927), and Kay (1941). These noted 

similarities between these rocks and rocks of the 

Taconic sequence of New York and New England.

Stose (1946) referred to these rocks as the "Hamburg 

klippe." Proponents of the Hamburg klippe maintained 

that the rocks are lithologically different and older 

than the surrounding Martinsburg Formation.

Despite the arguments of Stose, Kay, and other 

geologists, Gray and Willard (1955) asserted that the 

variegated shale and associated rocks are facies equivalents of the parauthochthonous Martinsburg Formation and are not allochthonous. In addition, McBride 

(1962) in his study of the Martinsburg in New Jersey, 

Pennsylvania, and Virginia, recognized no allochthonous rocks.

In the late 1960's and early 1970's, several geologists studied the Hamburg klippe. Field studies by 

Myers (1969) and Platt and others (1972) showed that 

there are, indeed, allochthonous elements within the 

Great Valley. These studies, supported by faunal evidence, have shown that the rocks of the Hamburg 

klippe are older than the surrounding Martinsburg 

Formation. An Early Ordovician age for the klippe 

rocks was indicated.

Root (1977) and Root and MacLachlan (1978) discussed the stratigraphy and structure of the western 

end of the Hamburg klippe. Recently, Lash (1980a, b) 

and Kodama and Lash (1980) have described a plate 

tectonic model for the emplacement of the Hamburg 

klippe.

GEOLOGIC FRAMEWORK

In the Kutztown quadrangle, the rocks of the 

Hamburg klippe are thrust to the north onto the Shochary Ridge sequence (Lyttle and Drake, 1979) of 

interbedded graywacke and shale of Middle to Late 

Ordovician age (Wright and others, 1978, 1979). The 

allochthonous rocks in the Hamburg quadrangle are 

in fault contact with the clastic Upper Ordovician(?) 

and Lower and Middle Silurian rocks of the Shawangunk Formation and Upper Ordovician and Lower 

Silurian(?) rocks of the Spitzenberg Conglomerate of 

Whitcomb and Engel (1934). These rocks mark the 

southern boundary of the Valley and Ridge in the area 

of study. The allochthonous rocks are bounded to the 

south by parautochthonous rocks of the Lehigh Valley 

sequence, the contact being the Kutztown thrust, a 

gently southeast-dipping fault.

The Lehigh Valley sequence (MacLachlan, 1967) 

consists of the Allentown Dolomite, Beekmantown 

Group, Jacksonburg Limestone, and Martinsburg Formation (fig. 2). These rocks form the cover sequence of 

some of the nappes of the Reading Prong nappe megasystem of Drake (1978), a system of crystalline-cored,
GEOLOGIC FRAMEWORK

stacked nappes in the Great Valley of east-central 

Pennsylvania and western New Jersey. The Lehigh 

Valley sequence, therefore, is considered a parautochthonous sequence in the Alpine sense.

TERMINOLOGY

Some mention of terminology employed in this 

paper should be made. Bouma sequences (fig1 . 3) are 

used in a descriptive and nongenetic sense in discussions of the clastic rocks. The rock color chart (Goddard 

and others, 1948) is used to describe rock colors on 

fresh surfaces except where otherwise noted. Bedding 

parameters cited in the lithologic descriptions are 

from McKee and Weir (1953).

STRATIGRAPHY AND SEDIMENTATION

Field mapping, which led to this paper, indicates 

that the allochthonous rocks at the eastern end of the 

Hamburg klippe occur in two tectonic slices or lithotectonic units (fig. IB). These slices are in fault contact 

and probably are bounded above by a thrust fault. The 

lower Greenwich slice, named for Greenwich Township 

in Berks County, Pa., is overlain by the Richmond slice, 

named for Richmond Township, Berks County, Pa.

Rocks within the Richmond slice of the Hamburg 

klippe comprise a sequence of quartzose rocks, carbonate rocks, and black and green shale and mudstone 

that is herein named the Virginville Formation. The 

tectonically underlying, but younger, Greenwich slice 

consists primarily of graywacke and shale and lesser 

amounts of limestone, chert, and conglomerate and is 

here named the Windsor Township Formation.

WINDSOR TOWNSHIP FORMATION

The Windsor Township Formation is here named 

for exposures along the east and west banks of Maiden 

Creek in Windsor Township, Berks County, between 

the towns of Dreibelbis and Kempton in the Kutztown 

and Hamburg 7%-minute quadrangles (fig. IB). The 

formation is predominantly a graywacke-shale unit 

that locally contains boulder conglomerate and slivers 

of limestone, chert, and variegated shale and mudstone. The Windsor Township Formation is divided 

into three mappable members, here named (1) Weisenberg, (2) Switzer Creek, and (3) Dreibelbis. The 

Weisenberg is predominantly a shale, siltstone, and 

mudstone unit, and the Switzer and Dreibelbis are 

graywacke-shale sequences.

The Windsor Township Formation was mapped 

as "Lithotectonic Unit A" by Alterman (1972). She

demonstrated that rocks of the Hamburg klippe and 

the Martinsburg Formation are different and should 

not be treated as lithologic equivalents. Our detailed 

mapping substantiates Alterman's contention thatthe 

Windsor Township is a distinct lithotectonic and rockstratigraphic unit.

Intraformational faulting and the lack of marker 

beds preclude an accurate thickness determination, 

but the unit has a minimum thickness of 6,215 m, 

calculated on the basis of cross sections constructed for 

the Kutztown quadrangle (Lash, in press). This thickness may be somewhat high because of internal deformation.

WEISENBERG MEMBER

The rocks within the Weisenberg Member of the 

Windsor Township Formation consist of poorly cleaved 

to fissile, light-olive-gray (5F 5/2) to olive-gray (5F 

3/2) and grayish-olive (10F4/2) shale, mudstone, and 

claystone to micaceous siltstone, containing local interbeds of medium-dark-gray (7V4) to dark-greenish-gray 

(5GY 4/1) slightly silicified shale and mudstone. 

Locally associated with the pelitic rocks are wellsorted, parallel to cross laminated pale-brown (5YR 

5/2) and yellowish-gray (5F 7/2) thin-bedded siltstone, showing well-developed slump folds. The member also contains minor amounts of graywacke and 

chert. Polymict conglomerate deposits, here called the 

Werleys conglomerate and informally used to identify 

lenticular channel fill deposits in the Weisenberg 

Member, contain clasts of carbonate rock, silicified 

mudstone, and chert that are locally conspicuous. 

They are interpreted to be debris flows.

The Werleys conglomerate is best exposed in outcrops about 1,070 m east of Werleys Corner in the 

Slatedale 7 1/2-minute quadrangle (fig. IB). The conglomerate is a poorly sorted, polymict lenticular channel fill that contains clasts of limestone, shale, and 

sparse volcanic rocks. Clasts are as much as 7.5 cm in 

diameter. Weathering of the limestone clasts gives the 

rock a characteristic pitted appearance. Although 

outcrops are sparse, Werleys conglomerate is abundant in the Topton and Slatedale quadrangles and, to a 

lesser extent, in the New Ringgold and Kutztown 

quadrangles.

The Weisenberg Member is named for a series of 

exposures located about 1 km south of Weisenberg 

Church in the Slatedale quadrangle (fig. IB). It varies 

in thickness from one area to another, depending on 

the presence or absence of the graywacke members 

discussed above. The thickest sequence of the Weisenberg in the area studied is 1,740 m, an estimate based
41°-

RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA 

79° 77° 75°

Va lley and Ridge

20 30

I

40 50 MILES

I

I 

20

I 

30

I I 

40 50 KILOMETERS

EXPLANATION 

GREAT VALLEY ROCKS

1 Allochthonous rocks 

Nx' Martinsburg Formation

Cambrian and Ordovician 

carbonate rocks and quartzite

Proterozoic Y rocks
STRATIGRAPHY AND SEDIMENTOLOGY

76° 00' 75°45'

40°37'30"

40°30

 ;+. '.+".'4 * .".+. .

' ' ' '

. .+ . *+ .. 4- 4 .4'

0 Hamburg /reservoir

Lenhartsville 

Breibelbts*

5 MILES

7 KILOMETERS

EXPLANATION

Silurian and younger rocks 

Rocks of the Greenwich slice

Rocks of the Richmond slice

Parautochthonous Lehigh Valley sequence 

(includes the Pen Argyl Member of the 

Martinsburg Formation)

FIGURE 1. Maps of eastern Pennsylvania. A. Map showing location 

of study area. B. Generalized geologic map of part of eastern 

Pennsylvania and western New Jersey. After Root and MacLachlan (1978). C. Generalized geologic map of the Kutztown 

and Hamburg 7%-minute quadrangles and surrounding areas. 

Geology of the Temple quadrangle modified from Wood and

^^H Shochary Ridge sequence

 T Steeply dipping upthrust 

arrow on upper plate

 * Low-a nglethrustfau It 

teeth on upper plate

~*~^ Tear fault

 Normal fault

MacLachlan (1978). Geology of the New Ringgold, New Tripoli, 

and Slatedale quadrangles from Lyttle and Drake (1979). 

Quadrangles are Orwigsburg, OR; New Ringgold, NR; New 

Tripoli, NT; Slatedale, SL; Auburn, AU; Hamburg, HB; Kutztown, KU; Topton, TO; Bernville, BE; Temple, TE; Fleetwood, 

FL; and Maxatawny, MA.
RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

o

>

o

Q 

GC 

O

GC

DQ

O

Trentonian

Martinsburg 

Formation

Black River

Chazyan

Canadian

Upper

Middle

<D 

<D 

00

Rickenbach Dolomite

-Stonehenge Limestone

Allentown 

Dolomite

Leithsville 

Formation

Lower

Hardyston Quartzite

FIGURE 2. Stratigraphic diagram of the Lehigh Valley sequence. 

Modified from MacLachlan (1967).

upon the construction of geologic cross sections in the 

Kutztown quadrangle (Lash, in press).

Contorted bedding is the only sedimentary structure in the pelitic rocks other than bedding. These 

folds are best seen in the light-brown siltstone. The 

individual laminations have moved relative to each

COMPLETE SEQUENCE

e petitic interval

d upper interval of parallel lamination

c interval of current ripple lamination

b lower interval of parallel lamination

a graded interval

TRUNCATED SEQUENCE

BASE CUT-OUT SEQUENCE

-77-7777??

FIGURE 3. Bouma sequence and variations. T indicates turbidite; 

small letters indicate the Bouma interval. From Bouma (1962).

other, resulting in small-scale recumbent folds and 

faults (fig. 4).

SWITZER CREEK MEMBER

The Switzer Creek Member is named for exposures of interbedded calcareous graywacke and shale 

along Switzer Creek in the Topton and Kutztown 

quadrangles (fig. IB). This member is characterized 

by thick-bedded, medium- to coarse-grained graywacke that contains local conglomerate beds that contain shale and limestone clasts. Gray wacke sequences,
STRATIGRAPHY AND SEDIMENTOLOGY

l/>*

. *,\ v.f .-ft,., v.

FIGURE 4. Contorted beds and faults in siltstone of the Weisenberg 

Member. Coin for scale.

not amalgamated, contain interbedded dark-greenishgray (5GY 4/1) to light-olive-gray (5 Y 5/2) micaceous 

siltstone to mudstone. The Switzer Creek has a minimum thickness of 815 m, an estimate based on the 

construction of geologic cross sections in the Kutztown 

quadrangle (Lash, in press).

The high porosity of the gray wackes of the Switzer 

Creek differentiates them from graywackes of the 

Dreibelbis Member. The porosity results from the 

weathering of the high proportion of limestone clasts 

and calcite cement in the sandstone. As a result of the 

weathering, the sandstone takes on a limonite-stained, 

rotten, pitted appearance.

Bedding in the Switzer Creek is thick to massive; 

locally, sequences of graywacke beds are amalgamated. In general, the rocks of the Switzer Creek contain a higher proportion of conglomeratic beds and Ta 

and Ta_e partial Bouma sequences than the Dreibelbis 

Member.

DREIBELBIS MEMBER

The rocks herein named the Dreibelbis Member of 

the Windsor Township Formation constitute a sequence of interbedded graywacke and greenish-gray 

siltstone, mudstone, -and shale best exposed along the 

west bank of Maiden Creek just north of Dreibelbis in 

the Hamburg 7%-minute quadrangle (fig. IB). The 

lack of marker beds precludes an accurate thickness 

determination; however, the Dreibelbis has an apparent thickness of 3,660 m, as based on cross sections 

constructed for the Kutztown quadrangle (Lash, in 

press).

The rocks of the Dreibelbis Member were mapped 

as Martinsburg Formation by Willard (1943) and 

reported as such on the 1960 Geologic Map of Pennsylvania (Gray and others, 1960). More recently, Alterman (1972) named it the "Berks Formation."

The Dreibelbis Member is made up of three main 

rock associations. These rock types are not mutually 

exclusive and appear to be intercalated on all scales. 

These rocks, particularly the more coarse grained 

units, appear to form lens-shaped bodies, but, because 

of the poor exposure, formation of lens-shaped bodies 

cannot be proven.

The first rock association is typified by laminated 

to thin- to very thick bedded, medium- to coarsegrained calcareous graywacke interbedded with fineto medium-grained, thin- to medium-bedded graywacke in Tc_e partial Bouma sequences and very thin 

beds of siltstone and mudstone (fig. 5). The graywacke 

is associated with thick sequences of dark-greenishgray (5GF 4/1) to grayish-olive-green (5GF 3/2) to 

light-olive-gray (5F5/2) fissile to poorly cleaved silty 

shale. These rocks are only locally exposed, the best 

exposures being along Route 143 approximately 370 m 

west of Albany in the northwest corner of the Kutztown 

quadrangle (fig. IB).

Graywacke beds attain a maximum thickness of 

about 3 m. Bottom and top contacts are always sharp. 

Sole marks indicative of erosion (for example, groove 

casts as much as 20 cm in width) are common (fig. 6). 

Shale clast conglomerates occur locally. Thick graywacke beds are massive except for sparse parallel and 

long-wave-length ripple laminations. Sequences of 

amalgamated graywacke beds are locally conspicuous. 

Grading is uncommon.

Few of the thinner graywacke beds exceed 9 cm in 

thickness. These rocks are finer grained than the 

thicker graywackes. Most of these beds are not laterally continuous and may pinch out within the length of 

an outcrop. The partial Bouma sequence Tc_e is common, although Tb_e sequences occur in some outcrops. 

Well-developed parallel and ripple laminations, conFIGURE 5. Sequences of thick-bedded graywacke, siltstone, and 

mudstone of the Dreibelbis Member. Hammer lies along the 

contact of the graywacke beds (to the right of the hammer) and a 

thick sequence of mudstone and siltstone. Roadcut along Route 

143 approximately 370m west of Albany. Kutztown quadrangle.
RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

FIGURE 6. Groove casts on the sole of a thick graywacke bed. 

Roadcut along Route 143 approximately 370 m west of Albany, 

Kutztown quadrangle. Brunton compass for scale.

volute bedding, and graded bedding are conspicuous 

in these graywackes, whereas sole marks are sparse. 

The second rock association is characterized by 

sequences of thick- to very thick bedded, massive to 

parallel and long-wave-length ripple laminated, 

medium- to coarse-grained and locally conglomeratic, 

somewhat calcareous graywacke sandstone and lesser 

proportions of interbedded light-olive-gray (5 Y 5/2) to 

dark-greenish-gray (5GY 4/1) fissile siltstone and 

mudstone (fig. 7). The graywackes are poorly to well 

graded, and the partial Bouma sequence Ta_e is common, although Ta_ b and sparse Tb_e and Tc_e sequences 

are known. Individual graywacke beds as thick as 3 m

FIGURE 7. Predominantly thin- to thick-bedded graywacke with 

thin pelitic intercalations. Roadcut along Route 143 approximately 610 m north of Dreibelbis, Hamburg quadrangle. 

Hammer for scale.

were measured, but the average thickness is between 

0.5 and 1 m. Pelitic intercalations range from thin, 

discontinuous lenses to individual beds with an average thickness of approximately 12 cm.

Bedding is flat and parallel, and individual beds 

appear to be laterally continuous in outcrop. Most sole 

marks are scours, although lesser load and flute casts 

(fig. 8) are known. Some outcrops have flame structures 

along the contacts of massive graywacke beds with 

underlying pelitic intervals. Contorted beds suggestive 

of slump folds also are present in these rocks (fig. 9).

The third rock association of the Dreibelbis Member is characterized by medium to thick beds of finegrained, locally calcareous sandstone interbedded with 

greenish-gray (5GY 4/1) fissile siltstone, mudstone, 

and claystone-shale. The Tc_e partial Bouma sequence 

containing well-developed convolute bedding, and ripple lamination is extremely common. Both Tb_e and Td_e 

partial Bouma sequences are known but are not common. Sole marks are sparse and consist mainly of load 

casts and lesser groove and flute casts.

FIGURE 8. Flute casts on the sole of a thin Tc_e turbidite. Current 

direction is from right to left (northeast). Rock is associated 

with thick channel-axis turbidite and grain-flow sandstones. 

Exposure approximately 2.4 km north of Lenhartsville, Hamburg quadrangle. Coin for scale.
STRATIGRAPHY AND SEDIMENTOLOGY

FIGURE 9. Contorted graywacke beds. Note the lack of folding in 

overlying mudstone and siltstone. Roadcut approximately 2.4 

km northeast of Windsor Castle, Hamburg quadrangle. Shovel 

for scale.

These rocks are best seen in a series of exposures 

along the west bank of the Schuylkill River about 1.5 

km south of Hamburg in the.Hamburg quadrangle 

and in exposures along a secondary road approximately 1.2 km southeast of the Hamburg reservoir, 

also in the Hamburg quadrangle (fig. IB).

MISCELLANEOUS UNITS

Lenticular to tabular bodies of poorly cleaved to 

fissile, red and light-green mudstone and shale interbedded with limestone and chert are ubiquitous within 

the Windsor Township Formation. They are randomly 

distributed and are not restricted to a specific member. 

As a result, these rocks have only local stratigraphic 

significance. Individual bodies of the variegated shale 

and associated rocks are as much as 240 m thick but 

are generally thinner.

These rocks consist of dusky-red (5R 3/4) to very 

dusky red (WR 4/2) and grayish-red (5R 4/2) mottled 

mudstone and argillite to micaceous shale that is 

locally interbedded with laminated to thin-bedded 

siltstone. Associated with the red shale and mudstone 

are roughly equal amounts of grayish-yellow (5 Y 8/4) 

and pale-green (10G 6/2) to light-green (5 G 7/4) mudstone and micaceous siltstone. At some places, thinbedded, well-sorted siltstone is interbedded with the 

shale and mudstone.

Green and, less commonly, white chert and quartzite are interbedded with the mudstone and shale. 

Preliminary petrographic examination of the chert 

shows variable amounts of detrital quartz in a cryptocrystalline matrix. Millimeter-scale laminae of dolomite rhombs alternate with more quartzose laminae 

in some sections. Chert beds are as thick as 25 cm (fig. 

10), but most are less than 5 cm thick.

FIGURE 1U. Thick-bedded chert interbedded with red and light 

green shale and mudstone. The competent chert was boudined 

by hard rock deformation. Roadcut along Route 143 approximately 360 m west of Albany, Kutztown quadrangle. Hammer 

for scale.

Parallel lamination is the only sedimentary structure seen. The majority of the chert beds are discontinuous and display pinch-and-swell and pull-apart 

structures. The development of pinch-and-swell and 

pull-apart structures appears to be, in part, the result 

of tectonism, but differential compaction of the chert 

and mudstone probably was also a factor.

The red and green mudstone is associated with a 

grayish-black (N2) to medium-dark-gray (7V4) to lightgray (N7) weathering, thin-bedded calcilutite (micrite) 

to calcisiltite. In some exposures, these rock types are 

separated by thin laminae of black (Nl) shale. These 

rocks contain a variable amount of quartz, so that 

some of the carbonate rocks may be better described as 

quartzose limestone. Sedimentary structures are 

limited to parallel lamination and ripple cross lamination including climbing ripples. The laminations are 

especially well shown on weathered surfaces. Locally, 

the limestones are extremely distorted, suggesting 

differential compaction and slumping.
10 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

A limestone slide block or megaclast approximately 25 m in length was described by Epstein and 

others (1972) from an outcrop about 1.5 km east of 

Lenhartsville in the Kutztown quadrangle. This megaclast is composed of light-gray (N7) calcisiltite with 

starved ripples and climbing ripples surrounded by 

laminated dark-gray (N3) to medium-dark-gray (7V4) 

calcareous shale (fig. 11).

Numerous smaller clasts have been found that are 

lithologically similar to the megaclast. These clasts 

apparently slumped into the green and red shales that 

surround them (Epstein and others, 1972). A similar 

deposit can be seen along the abandoned Reading 

Railroad grade on the east bank of Maiden Creek 

approximately 610 m southeast of Dreibelbis in the 

Hamburg quadrangle.

Contorted beds indicative of slumping (fig. 12) are 

well exposed in an outcrop of red mudstone and white

FIGURE 11. Limestone megaclast consisting of starved ripples surrounded by calcareous shale. Exposure located approximately 

1.5 km east of Lenhartsville, Kutztown quadrangle. Lens cover 

for scale.

FIGURE 12. Chaotic slump folds in interbedded red mudstone and 

white dolomitic chert. Roadcut along Route 143 approximately 

760 m southwest of Albany, Kutztown quadrangle. Coin for 

scale.

dolomitic chert about 760 m southwest of Albany on 

Route 143 in the Kutztown quadrangle. At this locality, a 6.1-m-thick zone of rock has been folded. The 

folds are generally disharmonic, and, in some cases, an 

axial plane cleavage has formed. Moore and Geigle 

(1972) have described similar deformation in Holocene 

sediments in the Gulf of Mexico in which an incipient 

cleavage has formed axially planar to folds. Stone 

(1976) noted a similar phenomenon in glacial sediments in New England.

Polymict boulder conglomerate (figs. 13 and 14) 

crops out along Route 737 approximately 2 km north of 

Kutztown in the Kutztown quadrangle in an exposure 

approximately 1,435 m long. The boulder conglomerate contains clasts and megaclasts of calcareous graywacke, dark-greenish-gray (5GF 4/1) mudstone and

FIGURE 13. Large graywacke clast (megaclast) in boulder conglomerate. Roadcut along Route 737 approximately 2 km north 

of Kutztown, Kutztown quadrangle.
STRATIGRAPHY AND SEDIMENTOLOGY 11

FIGURE 14. Irregularly shaped graywacke megaclast in boulder 

conglomerate. Note scaly cleavage in the matrix surrounding 

the clast. Roadcut along Route 737 approximately 2 km north of 

Kutztown, Kutztown quadrangle.

shale, grayish-black (N2) to dark-gray (JV4) parallel 

laminated calcilutite and calcisiltite, pale-reddishbrown (WR 5/4) sandstone, and chert, all of which are 

rock types that occur in the Windsor Township Formation, randomly oriented in a highly contorted matrix 

of medium-dark-gray (JV4) to dark-greenish-gray(5GF 

4/1) and grayish-olive (10 Y 4/2) to pale-green (10G 

6/2) shale and mudstone that wraps around the clasts. 

Graywacke clasts are dominant and range in size from 

less than 2 cm to 3 m or more in length. Some of the 

larger blocks are "polished" along their bottom surfaces, indicating that they slid into place.

Detailed study of the exposure along Route 737 

indicates that the boulder conglomerate is zoned with 

respect to clast lithologies and sizes. Moving north 

along Route 737, the first 305 m of the conglomerate 

contains clasts of shale, mudstone, reddish-brown siltstone, and limestone. The largest clast is approximately 0.3 m long. This rock type grades into 915 m of 

conglomerate that contains extremely large clasts or 

megaclasts of graywacke, mudstone, and limestone. 

The next 30 m or so of conglomerate contains calcilutite clasts almost to the exclusion of all other types. The 

matrix for these clasts is the distinctive pale-green 

(10G 6/2) mudstone that so commonly occurs in the 

units of chert, limestone, and variegated shale and 

mudstone. The remaining 185 m of conglomerate contains small clasts of graywacke, shale, and limestone.

All clasts and the matrix of the boulder conglomerate are rock types that occur in the Windsor Township Formation. The graywacke is texturally and 

mineralogically distinct from the graywacke of the 

Ramseyburg Member of the parautochthonous Martinsburg Formation to the south. In addition, the

pelitic matrix of the boulder conglomerate is not the 

dark-gray (jV4) claystone slate that is typical of the 

Bushkill and Ramseyburg Members of the Martinsburg Formation but is typical of the Windsor Township 

Formation. This distinction becomes very important 

in deciding whether or not the boulder conglomerate 

represents a wildflysch in the Martinsburg.

Alterman (1972) first recognized this conglomerate and described it as a "wildflysch-type" of conglomerate, which heralded the approach of an allochthonous slice into the Martinsburg basin in much the 

same way as the wildflysch described by Bird (1969) 

and Zen (1972) heralded the advance of the allochthonous slices during sedimentation in the klippen of New 

York and New England. Analysis of the clasts in the 

conglomerate indicates that the clasts were derived 

from within the Windsor Township depositional basin, 

not the Martinsburg basin, and suggests a slumped 

level in the sense of Elter and Trevison (1973) with no 

input from sources outside the basin. The boulder conglomerate, therefore, should be considered as an 

intrabasin slump deposit.

GRAYWACKE PETROGRAPHY

Modal analysis of graywackes of the Dreibelbis 

and several samples of the Switzer Creek Members of 

the Windsor Township Formation indicates that they 

can be classified as quartzose to sublabilearenites (fig. 

15), according to the classification of Crook (1960). The 

small amounts of unstable rock fragments and feldspar 

in the graywackes indicate that the graywacke detrital suite of the Dreibelbis is mature. Limited study of 

the graywackes of the Switzer Creek indicates that 

their detrital suite is somewhat less mature and contains slightly more lithic fragments and feldspar.

Quartz is by far the most abundant mineral in the 

sandstones of the Dreibelbis Member. Plagioclase 

(albite to sodic oligoclase) is the dominant feldspar and 

ranges from very clean, angular grains to almost completely sericitized grains. In general, detrital feldspar 

grains are smaller and more angular than accompanying quartz grains. Lithic fragments include mudstone 

and shale, limestone, and polycrystalline quartz 

(quartzite and chert). The mudstone and shale were 

derived from underlying pelitic intervals. Carbonate 

is an extremely variable component and occurs as 

cement, as authigenic rhombohedra of ankerite, and 

rarely in detrital grains. A few lithic clasts of argillite 

and possibly slate also were noted. The matrix of the 

graywacke consists of variable proportions of quartz, 

sericite, and carbonate.

Analysis of the quartzose-feldspar-lithic fragments (QFL) plot (fig. 15) indicates that the plot cannot differentiate sandstones of the Dreibelbis Member
12 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

Quartzose arenites

Sublabile arenites

Feldspathic labile 

arenites

FIGURE 15. Classification diagram (QFL plot) for the graywackes of the Windsor Township Formation. The diagram employs the 

classification scheme of Crook (1960). Q, monocrystalline and polycrystalline quartz; F, total feldspar; and L. lithic (rock) fragments.

from those of the Switzer Creek Member. In addition, 

other plots such as Q,,,FL (Q,( ,=monocrystalline quartz) 

and QFL, (L,=lithic grains) yield similar results. The 

main petrographic difference between the two units is 

the carbonate content, as can be seen in table 1. The 

graywackes of the Switzer Creek are obviously much 

higher in carbonate than those of the Dreibelbis. This 

difference is reflected in the weathered appearance of 

the Switzer Creek graywackes.

PROVENANCE

The importance of province studies in understanding the interplay of tectonics and sedimentation

of a specific area was stressed by Suttner (1974). In 

addition, Dickinson (1970, 1971) contributed greatly 

to our knowledge of the various tectonic settings of 

graywackes of arc associations of the circum-Pacific 

region. His work indicates that graywackes derived 

from volcanic-arc settings are characteristically high 

in volcanic rock fragments and plagioclase.

Graham and others (1975) studied craton-derived 

graywackes from the Black Warrior Basin and the 

Ouachitas. They noted an almost total lack of volcanic 

detritus and feldspar and an overwhelming predominance of quartz in the detrital suite. The source area 

for these rocks is characterized by sedimentary rocks,
STRATIGRAPHY AND SEDIMENTOLOGY 

TABLE 1. Modal analyses of arai/icackexfrom the Windsor Toirnship Formation

[3, 9. 12, 13, 14, and 18, Switzer Creek Member; all others, Dreibelbis Member. A minimum of 400 points counted per section]

13

Constituent

Plagioclase

Potassium feldspar

Carbonate

Accessories

Matrix

Sample numbers

1

35.6

3.4

.4

..... 5.5

..... 0.0

0.3

.6

..... 55.3

2

39.8

2.2 

.5 

2.5

4.7

2.2

47.4

3

43.6

2.2 

0.0 

9.6

11.0 

1.3

1.9

31.4

4

46.8

3.3 

2.0 

6.0 

2.0 

2 

2.0 

40.1

5

49.9

1.7 

.5 

4.4 

0.0 

1.2 

3.6 

39.9

6

.9 

.7 

3.8 

10.3 

1.0 

1.6 

37.2

7

1.9 

.9 

1.9 

6.6 

.5 

2.4 

49.4

8

26.9

2.7 

1.3 

4.2 

5.1 

.4 

.6 

57.7

9

23.0 

2.0 

.7 

5.5 

10.5 

.7 

16 

57.2

10

47.7 

2.2 

2.1 

7.3 

6.7 

.5 

.6 

32.9

11

38.4 

7.2 

2.9 

6.2 

9.3 

2

1.9 

36.3

12

38.6 

2.5 

.5 

3.4 

23.0 

.3 

2

31.5

13

25.4 

.5 

0.0 

0.0 

2.6 

1.0 

1.4 

69.1

14

43.5 

1.9 

1.0 

.7 

19.0 

.5 

1.0 

32.4

15

46.6 

4.3 

.5 

3.8 

8.6 

.3 

.7 

35.9

16

52.6 

1.7 

.5 

3.6

7.3 

.4 

.7 

35.1

17

36.6 

.2

.7 

10.5 

7.6 

.8 

.7 

43.9

18

46.7 

1.2 

.2 

.9 

10.8 

2

3.8 

36.2

low-grade metamorphic rocks, and some plutonic 

rocks.

Crook (1974) suggested a correlation between the 

framework constituents of graywackes and their tectonic setting. He proposed that the three types of continental margins described by Mitchell and Reading 

(1969) have distinct compositional varieties of graywackes associated with them. They are (1) quartz-rich 

modern deep-sea sand and ancient graywacke (greater 

than 65 percent quartz) that is typical of Atlantic-type 

continental margins, (2) quartz-intermediate modern 

sand and ancient graywacke (15 to 65 percent quartz) 

that typifies trench sediments along Andean-type 

margins, and (3) quartz-poor modern sand and ancient 

graywacke (less than 15 percent quartz) that is found 

along western Pacific margins in trenches external to 

volcanic-arc systems. This work has been substantiated 

by Schwab (1975) who included more data from modern and ancient sands.

The graywacke of the Windsor Township Formation falls within the quartz-rich field of Crook (1974) 

(fig. 16). Graywackes of this classification probably are 

derived from a predominantly sedimentary province 

containing minor plutonic and low-grade metamorphic 

admixtures. The presence of variable amounts of carbonate may reflect some input from a carbonate shelf.

The petrographic data, therefore, are consistent 

with a cratonic source characterized by sedimentary 

rocks, low- to medium-grade metamorphic rocks, and 

some plutonic rocks. The mineralogy of the sandstones 

suggests an Atlantic-type margin.

AGE AND CORRELATION

The age of the Windsor Township Formation is still 

an enigma in spite of recent paleontological studies. 

Wright and others (1978, 1979) report a Middle Ordovician (Nemagraptus gracilix zone) age on the basis of 

graptolite collections from graywacke and gray-green 

shale. Perissoratis and others (1979) report that graptolites from rocks of the Jutland klippe in New Jersey 

(see fig. 14), a sequence of rocks lithologically similar 

to the limestone, chert, and variegated shale units of

the Windsor Township, range in age from Early 

(graptolite zones 2 to 4 of Berry, 1960,1968) to Middle 

(graptolite zones 11 to 12 of Berry, 1960,1968) Ordovician.

Bergstrom and others (1972) collected Early Ordovician conodonts from the limestone megaclast (fig. 

11) mentioned in the description of the red and green 

shale units (p. 10). In addition, these collections contain 

a Balto-Scandic fauna, as opposed to a North American 

mid-Continent fauna of the coeval Beekmantown Group 

(Bergstrom and others, 1972). The Early Ordovician 

age is similar to some of the graptolite ages of the 

lithologically similar Jutland klippe but does not agree 

with the graptolite fauna of the graywacke and graygreen shale sequence of the Windsor Township Formation.

Recent graptolite collections from rocks of the 

Weisenberg Member (P.T. Lyttle, oral commun., 1978) 

support a Middle Ordovician age (Nemagraptus gracilis zone) for the gray-green shale and graywacke of the 

Windsor Township. In addition, conodonts collected 

from limestone associated with several of the chert, 

limestone, and variegated shale and mudstone units 

are of Early Ordovician age and constitute a BaltoScandic fauna. A Middle Ordovician conondont was 

recovered from a chert, limestone, and variegated 

shale unit (J. E. Repetski, written commun., 1978), 

indicating that some of these rocks are coeval with the 

rocks of the graywacke-gray-green shale sequence.

These recent data support the age discrepancy 

described above and suggest, therefore, that a majority 

of the lenticular bodies of limestone, chert, and red and 

green shale, generally of Ordovician age, are allochthonous with respect to the Middle Ordovician graywacke-gray-green shale sequence of the Windsor 

Township Formation (fig. 17).

Recently, detailed stratigraphic studies at the 

western limit of the Hamburg klippe (Root, 1977; Root 

and MacLachlan, 1978) have shown that two allochthonous slices are in that area the Enola allochthon 

and the structurally overlying Summerdale allochthon. Rocks of the Enola allochthon, of uncertain age,
14 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

California Great Valley 

sequence

Overall limit 

Main clustering

Jackfork Sandstone

Ouachita Mountains flysch

Atoka Formation

Pottsville Formation

FIGURE 16. Triangular (QFL) plot comparing detrital modes for the New Zealand graywackes, California Great Valley sequence, Black 

Warrior Basin (Jackfork Sandstone, Atoka Formation, and Pottsville Formation), and Ouachita Mountains flysch (Graham and others, 

1975) and those of the present study (black dots). New Zealand and California Great Valley sequence graywackes are derived from a 

magmatic arc. The other graywacke suites are cratonic derived. Q, mono- and polycrystalline quartz; F, total feldspar; and L, lithic 

(rock) fragments.

are characterized by chert, limestone, and variegated 

shale and are quite similar, lithologically, to the variegated shale and mudstone units of the Windsor Township Formation. The Summerdale allochthon, also of 

uncertain age, consists of "greenish to medium-gray 

shales containing interbeds of calcareous graywacke 5 

to 60 cm thick" and "arenaceous conglomeratic limestones and subordinate platy limestone" (Root and

MacLachlan, 1978, p. 1521). Root and MacLachlan 

recognized the lithologic similarity of the carbonate 

rocks of the Summerdale allochthon to the carbonate 

rocks associated with the chert and variegated shale 

units of the Windsor Township. Therefore, the rocks of 

the Summerdale allochthon at the western end of the 

Hamburg klippe can be correlated with the rocks of 

the Windsor Township of the Greenwich slice.
STRATIGRAPHY AND SEDIMENTOLOGY 15

CJ

o

0 

CC 

O

CL 

CO

O

Trentonian

Black River

Chazyan

Canadian

Upper

FIGURE 17. Relations between the Lehigh Valley sequence, the 

Jutland klippe, and Windsor Township Formation. Age data 

from Bergstrom and others (1972), Epstein and Berry (1973), 

Wright and others (1978), Perissoratis and others (1979), and J. 

E. Repetski (written commun., 1978, 1979, 1980).

ENVIRONMENT OF DEPOSITION

Field and laboratory studies of the flyschoid rocks 

of the Windsor Township Formation suggest that the 

rocks represent middle-fan deposits of a large submarine fan. The submarine fan model and facies relations 

and terminology of the flysch deposits of the Hecho 

Group in the Spanish Pyrenees, as described by Mutti 

(1977) (fig. 18), have been adopted and somewhat modified for the study of the Windsor Township. The Dreibelbis Member is divided into three principal channel 

facies by using the classification of Mutti (1977): (1) the 

channel-margin facies, (2) channel-axis facies, and (3) 

interchannel facies. Detailed field mapping indicates 

that these facies are intercalated and suggests that the 

channel margin was shifting laterally with time.

The channel-margin facies is characterized by the 

thick- to very thick bedded, coarse-grained gray wacke 

that is interbedded with fine- to medium-grained, thin 

bedded Tc_ e graywacke and siltstone and mudstone 

described on p. 8. The thick graywacke beds were 

probably deposited as grain flows. Mutti and RicciLucchi (1978) maintain that deposits of this type are 

limited to the infilling of submarine valleys and channels. The thin-bedded Tc_e beds are probably the result 

of dilute turbidity currents associated with deposition 

of the thick beds. Nelson and others (1974) and Mutti 

and Ricci-Lucchi (1978) proposed that these "distal" 

deposits can be interpreted as thin levee and overbank 

deposits related to the emplacement of the thick graywackes and, therefore, are deposited in a "proximal" 

environment.

The channel-axis facies is characterized by the 

monotonous sequences of thick-bedded, calcareous 

graywacke sandstone that contains lesser proportions 

of intercalated mudstone and siltstone. The thick 

sequences of graywacke so characteristic of the S witzer 

Creek Member of the Windsor Township Formation 

are probably channel-axis facies rocks. The channelaxis facies can be subdivided into two subfacies on the 

basis of somewhat different sedimentary structures. 

Channel-axis subfacies I is characterized by thick- to 

very thick bedded massive graywacke sandstone. 

Scour marks are common on the soles of these beds. 

This subfacies is similar to "Facies A" of Mutti and 

Ricci-Lucchi (1978) and appears to have been deposited 

as grain flows or fluidized flows or a combination of 

both. The channel-axis subfacies II is characterized by 

medium- to thick-bedded, parallel- and long-wavelength ripple laminated graywacke beds. These rocks 

were apparently deposited as grain flows that had 

tractive action during deposition (Mutti and RicciLucchi, 1978). This subfacies is similar to "Facies B" of
16 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

Mutti and Ricci-Lucchi (1978).

The interchannel facies is characterized by the 

bundles of Tc_e partial Bouma sequences that are probably the result of dilute overbank turbidity currents 

associated with deposition of the thick graywackes of 

the channel-axis facies.

Rocks of the Weisenberg Member of the Windsor 

Township Formation are interpreted to be open-fan or 

levee mudstones and siltstones associated with the 

channel and interchannel facies rocks (see fig. 18) and 

as such resemble "Facies G" of Mutti and RicciLucchi's (1978) classification. These sediments are 

apparently the product of deposition from dilute turbidity currents and nepheloid layers. In addition, the 

planar- to ripple-laminated siltstones present in the 

Weisenberg may be "fossil contourites" (Bouma, 1972a, 

b) and the product of redistribution of material by 

bottom-following contour currents. Evidence supporting this theory includes the presence of distinct upper 

and lower bedding planes, a low matrix content, and 

the well-sorted nature of the siltstones. Heezen and 

Hollister (1964) have described evidence indicating 

the presence of these relatively fast-moving, contourfollowing currents along continental rises.

The spatial distribution and intercalation of the 

various channel facies of the Dreibelbis Member suggest that interchannel and channel deposits are not 

mutually exclusive. Nelson and Nilson (1974) have 

shown that thick-bedded, coarse-grained sandstones 

can be found in interchannel environments and vice 

versa. They and other geologists (Shepard, 1966; 

Normark, 1970) maintain that modern fans and associated channels meander and migrate laterally, resulting in the intermixing of facies. The spatial arrangement of facies in the Windsor Township Formation 

illustrates this migration of channels in an ancient fan 

deposit.

As stated at the beginning of this section, the flyschoid rocks of the Windsor Township Formation 

were deposited in the middle-fan area (supra fan?) of a

Channel-axis 

facies

\

Channel-margin 

facies Levee 

mudstone

Interchannel 

facies

Open-fan 

mudstone

Slumped 

mudstone

Broadly

channelized

interchannel

sandstone

beds

FIGURE 18. Depositional model for the flysch facies of the Windsor 

Township Formation excluding the units of variegated mudstone and shale, limestone, and chert and the boulder conglomerate. From Mutti (1977).

large submarine fan. Evidence for this environment of 

deposition includes the (1) predominance of coarsegrained, thick graywacke beds that appear to represent channel fills flanked by fine-grained sandstone, 

siltstone, and mudstone in probable levee and interchannel areas, (2) abrupt vertical and lateral variation 

and distribution of rocks thought to be of the channelaxis and interchannel facies, (3) the predominance of 

Ta and Ta_e partial Bouma sequences, and (4) the lack 

of the conglomeratic facies that is indicative of an 

inner fan environment. The Dreibelbis and Switzer 

Creek Members, therefore, are thought to be sequences of turbidite and grain-flow deposits that were 

incised into the underlying levee and open-fan mudstone and siltstone of the Weisenberg Member. The 

graywacke units may have a lenticular geometry, but 

this geometry is impossible to prove at present. Small 

lenticular bodies of conglomerate deposits, informally 

called the Werleys conglomerate, are channel fills (see 

p. 3) that have cut into the underlying mudstone and 

siltstone of the Weisenberg Member.

Middle-fan channels in the Windsor Township 

Formation are characterized as shallow, braided, and 

depositional as opposed to relatively straight and deep 

erosional channels more typical of inner fan deposits 

(Ingersoll, 1978).

The assemblage of thin-bedded chert, limestone, 

and variegated shale and mudstone within the Windsor Township represents a "starved sequence" deposited in deep water; this interpretation, however, was 

not always accepted. These rocks have, in the past, 

been interpreted to be shallow-water continental sediments (Willard, 1939,1943), although McBride( 1962). 

somewhat later, maintained that they were deepwater 

marine muds. The carbonate rocks interbedded with 

the chert and variegated shale of the Windsor Township lends further support to a deepwater, bathyal or 

abyssal environment of deposition. Wilson (1969), 

Cook and Taylor (1977), and Scholle (1978) presented 

criteria elsewhere to distinguish deepwater limestone, 

deposited below wave base, from shallow-water limestone. The dominance of micrite and lesser amounts of 

calcisiltite, the lack of shallow-water structures, the 

presence of millimeter-scale planar and ripple laminations, and the dark color of the limestone within the 

Windsor Township suggest deposition in an environment below wave base. In addition, the Balto-Scandic 

conodont fauna present in these rocks, a cold-water 

fauna, is also suggestive of great depths of deposition. 

Studies of Holocene sediments by Bouma and Hollister (1973) indicate that red and brown clays are presently accumulating as deep-sea sediments at depths 

greater than 5,000 m. Although the carbonate rocks of 

the Windsor Township are deepwater limestones, the
STRATIGRAPHY AND SEDIMENTOLOGY 17

depth of the basin could not have exceeded the carbonate compensation depth of 4,000 to 5,000 m on the 

basis of average depths for modern ocean basins.

Most of the lenticular to tabular bodies of variegated shale and associated rocks are allochthonous 

with respect to the graywacke and gray-green shale of 

the Windsor Township Formation. One body contains 

a Middle Ordovician conodont (equivalent to the 

Nemagra))tus gracilis graptolite zone, J. E. Repetski, 

written commun., 1978) and is, therefore, coeval with 

the graywacke and gray-green shale sequence of the 

Windsor Township. This occurrence may indicate 

intertonguing relations between the two rock types.

Petrographic studies of the graywacke and siltstone of the Windsor Township Formation point to a 

cratonic source area. The few volcanic clasts in the 

Werleys conglomerate of the Weisenberg Member 

may be older rift volcanics related to opening of the 

proto-Atlantic ocean. Although provenance is difficult 

to prove, slump folds in the graywacke suggest a 

paleoslope dipping to the northwest and, therefore, a 

southeastern source.

In summary, the rocks of the Windsor Township 

Formation were deposited in the middle-fan area of a 

submarine fan that had a probable source area to the 

southeast. The fan was active, as evidenced by the 

irregular spatial arrangement of the various turbidite 

facies that indicates the lateral migration and meandering of the channels. Limestone, chert, and red and 

green shale and mudstone represent bathyal to abyssal sediments. Apparent age discrepancies of the 

graptolite-bearing graywacke-gray-green shale sequence and the majority of the conodont-bearing red 

and green shale units indicate that the latter were 

deposited as pelagic sediments and later incorporated 

into the younger fan flysch.

VIRGINVILLE FORMATION

The Virginville Formation, named for the town of 

Virginville in the southeastern part of the Kutztown 

quadrangle, is herein defined as the 565-m-thick sequence of quartzose rocks, micrite, calcarenite, peloidal limestone, carbonate-clast conglomerate, and black 

shale and mudstone structurally overlying the Windsor Township Formation. Miller (1937) referred to 

these rocks as "Martinsburg Shale" and "Martinsburg 

Limestone." More recently, Alterman (1972) recognized the exotic character of these rocks and established that they were allochthonous. Neither the limestone nor the siliciclastic rocks have any known 

counterparts in the Lehigh Valley sequence.

The Virginville Formation crops out in the southwest corner of the Kutztown quadrangle and the

southern part of the Hamburg quadrangle. Alterman 

(1972) mapped rocks resembling those of the Virginville in the Temple quadrangle south of the Hamburg 

quadrangle and west of the Schuylkill River as "Lithotectonic Unit A." Wood and MacLachlan (1978) showed 

that the Virginville probably extends well into western 

Berks County. They referred to these rocks as "Lithotectonic Unit 2" and "Lithotectonic Unit 4."

The Virginville Formation is divided into three 

members the Sacony, the Onyx Cave, and the Moselem. The Moselem is tectonically overlain by the Sacony and Onyx Cave.

SACONY MEMBER

The Sacony Member is herein named for exposures of siliciclastic rocks along Sacony Creek 1.6 km 

northeast of Virginville in the Kutztown quadrangle. 

The Sacony was described as "Martinsburg Shale" by 

Miller (1937). Alterman (1972) referred to these rocks 

as the "Virginville Formation." The Sacony has a minimum thickness of about 245 m, an estimate based 

upon the construction of geologic cross sections in the 

Kutztown quadrangle (Lash, in press).

The rocks of the Sacony are typically massive, 

grayish-olive-green(5GF 3/2) to pale-blue-green (5BG 

7/2) and locally grayish-red (WR 4/2) micaceous siltstone to sandstone containing intercalations of grayishgreen (10GF7/2) to pale-blue-green (5BG 7/2) micaceous shale and mudstone. They weather to a distinctive 

rust color, quite evident in the soil, which aids in mapping in areas of poor exposure. Bedding is marked by 

lithologic and color contrasts, as well as by planar 

surfaces having a micaceous sheen. Discontinuous 

layers of quartz and dolomite also delineate bedding.

A distinctive feature of the Sacony Member is the 

lenticular or ovoid masses of the rock seen in outcrop 

(fig. 19). These were noted by Alterman (1972) who 

believed that these masses have a sedimentary origin. 

A lack of internal structures that support this interpretation suggests that the masses result from 

weathering.

At places, minor amounts of chert and highly 

cleaved grayish-black (N2) to light-gray (M>) and 

light-green (5G 7/4) thinly laminated, silicified shale 

are interbedded with the sandstone and siltstone. A 

fissile grayish-black (N2) shale also is present at a few 

localities.

Averaged analyses of the siltstone and sandstone 

show that quartz is by far the predominant detrital 

mineral (24.0 percent), followed by plagioclase (2.5 

percent), opaque minerals (2.3 percent), brown mica 

(2.2 percent), white mica (2.0 percent), potassium 

feldspar (1.1 percent), and lithic fragments (0.5 percent). Lithic fragments, which never exceed 0.8 per-
18 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

limestone interbedded with very thin to thin-bedded 

black, very finely crystalline to argillaceous limestone, 

(3) very thick bedded, massive carbonate-clast conglomerate, and (4) thinly laminated black shale and 

orange to light-yellow dolostone and fine-grained limestone. Local minor occurrences of thick-bedded quartzite and quartzose dolostone to granular dolostone are 

also present. All of the rock types can be found within a 

single outcrop of the Onyx Cave. The minimum thickness of the Onyx Cave, on the basis of geological cross 

sections constructed in the Kutztown quadrangle, is 90 

m (Lash, in press).

Miller (1937) first described the carbonate rocks 

of the Onyx Cave Member, which he believed were 

interbedded with shales of the Martinsburg Formaation. In his study, he made no distinction between 

"Martinsburg Shale" and the green siltstone and 

sandstone of the Sacony Member described herein. On 

the 1960 Pennsylvania State Geological Map (Gray 

and others, 1960), the limestones of the Onyx Cave are 

shown as limestones of the Beekmantown Group. 

Alterman (1972) referred to these rocks as the "Cave 

Limestone Member" of the "Virginville Formation" 

and regarded them as allochthonous.

The Onyx Cave Member conformably overlies the 

Sacony Member. The contact can be seen in an exposure approximately 1.5 km southeast of Onyx Cave in 

the Hamburg quadrangle. At this locality, younging 

directions in the Onyx Cave indicate that the sequence 

is right side up. The transition from the Sacony to the 

Onyx Cave is rapid and takes place over a distance of 

less than 1 m. Miller (1937) noted this exposure and 

cited a 3-m transition zone, but detailed petrographic 

studies do not support this. Directly overlying the 

green siltstone of the Sacony is a sequence of thinly 

laminated black shale and orange dolostone and calcisiltite. This sequence is in turn overlain and interbedded with ribbon limestones, thick polymict carbonate-clast conglomerate, calcisiltite, and thick quartzose limestone.

The Onyx Cave Member crops out as isolated 

patches. These patches are erosional remnants from a 

once larger mass. All of the major caves in the area 

except one have been formed along faults within the 

Onyx Cave.

The medium-light-gray (M5) calcarenites and 

quartzose limestones are typically massive. Micrite 

pebbles are found in several beds. Bedding is typically 

planar and parallel, although local lenses of quartzose 

limestone and calcarenite (fig. 20) cut into the underlying shale and argillaceous limestone. These lenses 

have maximum thicknesses of 18 cm and maximum 

widths of 1.5 m. These carbonate rocks may have been 

deposited in channels incised into shale and mudstone.

FIGURE 19. Ovoid masses of Sacony Member siltstone. Beds dip to 

the left (south) at about 45°. Exposure is approximately 150 m 

north of Virginville, along the old Reading- Railroad grade, 

Kutztown quadrangle. Hammer in lower left corner for scale.

cent, are always polycrystalline quartz (chert). Detrital micas as long as 0.27 mm were noted and show 

complex kinking from compaction. Some of the mica is 

not detrital and is related to an incipient cleavage. 

Quartz grains exhibit a medium to low sphericity, 

range from angular to round, and have slightly to 

strongly undulose extinction. Matrix constitutes 50 to 

74 percent (average is 65 percent) of the rock and 

consists of chlorite, sericite, microcrystalline quartz, 

and minor amounts of brown mica.

ONYX CAVE MEMBER

The Onyx Cave Member of the Virginville Formation, herein named for exposures at Onyx Cave in the 

Hamburg quadrangle, conformably overlies the Sacony Member and is dominated by four distinct rock 

types: (1) thin- to thick-bedded, granular and quartzose 

limestone, (2) thin- to medium-bedded, parallel- and 

cross-laminated black lime mudstone to granular
STRATIGRAPHY AND SEDIMENTOLOGY 19

FIGURE 20. Peloidal limestone filling channels in black shale and 

lime mud of the Onyx Cave Member. Roadcut located approximately 640 m north of Virginville, Hamburg quadrangle. Coin 

for scale.

The greater part of the Onyx Cave Member is made 

up of thin- to medium-bedded black (Nl) to dark-gray 

(7V3) lime mudstone to pelmicrite interbedded with 

thinner grayish-black (N2) to medium-dark-gray (N4) 

weathering to light-gray (Nl) argillaceous lime mudstone or ribbon limestone. The limestones are typically 

parallel to cross laminated, but massive beds can be 

found. Graded beds are fairly common but are difficult to recognize in the field. Boudinage is common 

(fig. 21) and, since it does not appear to be tectonic, is 

apparently related to differential compaction of the 

mud and carbonate.

Slump folds are common within the ribbon limestones. Soft sediment slumps have been described in 

similar rocks associated with the Cow Head Breccia of 

western Newfoundland (Hubert and others, 1977).

FIGURE 21. Sedimentary boudinage in ribbon limestones of the 

Onyx Cave Member. Exposure located approximately 3 km 

north of Kutztown, Kutztown quadrangle. Coin for scale.

Because of their dark color, millimeter-scale 

planar and parallel beddng, scarcity of burrows, and 

lack of wave-produced structures, the limestone and 

shale are thought to have had a deepwater origin. Such 

criteria have been used elsewhere (Cook and Taylor, 

1977) to connote a deepwater environment.

Polymict carbonate-clast conglomerates or edgewise conglomerates occur throughout the Onyx Cave 

Member (figs. 22 and 23). Individual beds are massive 

and range from 0.8 to 1.7 m in thickness. Clasts include 

micrite (lime mudstone), calcarenite, quartzose limestone, peloidal wackestone, calcisiltite, and locally 

moderate-yellowish-brown (10 YR 5/4) dolostone. The 

clasts are derived from rocks common to the Onyx 

Cave. The majority of the clasts are tabular, ranging 

up to 25 cm in length, but well-rounded clasts also are 

common. Comminuted clasts show that they were of 

semi-indurated nature prior to deposition. Clasts 

within individual beds are not graded or sorted,

FIGURE 22. Polymict carbonate-clast conglomerate of the Onyx 

Cave Member. The matrix is arenaceous. Variation in size and 

angularity of clasts is great. Bedding is irregular and has cut 

into underlying beds. Exposure is about 3 km north of Kutztown, Kutztown quadrangle. Mallet for scale.
20 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

detail by numerous geologists (Walker, 1970, 1975; 

Cook and others, 1972; Cook and Taylor, 1977; Cook, 

1979; Krause and Oldershaw, 1979). Walker (1975) 

proposed descriptive models for conglomerates of turbidite associations on the basis of the presence or 

absence of grading (reverse or normal), stratification, 

and imbrication of clasts. Conglomerates in the Onyx 

Cave Member best fit Walker's disorganized bed 

model.

The conglomerates are associated with rocks interpreted to be turbidites. They may be channel fills, but 

no conglomerate bed was seen to pinch out within a 

single outcrop, and the lateral extent of the conglomerate beds is not known. Therefore, whether the conglomerates are sheet flows or channel flows cannot be 

determined.

Sequences of thinly laminated to laminated black 

and current-ripple-laminated (Nl) to dark-gray (N3) 

and dark-yellowish-orange (10 YR 6/6) to pale-yellowish-orange (1017? 8/6) dolostone and calcisiltite 

occur throughout the Onyx Cave Member. These 

sequences commonly show evidence of syndepositional 

deformation in the form of small folds and pinch-andswell structures.

Thick-bedded, massive quartzite and quartzose 

dolostone to dolarenite occur locally. Scarcity of exposures precluded any detailed investigation of these 

rocks.

FIGURE 23. Polymict carbonate-clasl conglomerate in the Onyx 

Cave Member containing- clasts oriented perpendicular to bedding. Bedding is parallel to the bottom of the photograph. 

Exposure is located near the Sacony Bridge, Kutztown quadrangle. Mallet for scale.

although a few beds are capped by planar-laminated 

beds of graded sand-sized quartz and limestone grains.

The conglomerate matrix typically consists of 

well-rounded, in some cases frosted, quartz grains and 

peloids. Two of the beds studied, however, have a mudstone matrix. In these rocks, the clast-matrix ratio is 

much higher than that of the conglomerates having a 

sandy matrix. Clast fabric ranges from slightly imbricated to randomly oriented. In several examples, 

clasts are perpendicular to bedding (see fig. 23). Generally speaking, the clast-matrix ratio, clast size, and 

clast lithology do not vary systematically in vertical 

sections of beds, although the clast-matrix ratio decreases slightly up section in a few beds. The upper 

surface of individual conglomerate beds is planar to 

irregular and in some exposures is characterized by 

scour-and-fill structures.

Conglomerates in the Onyx Cave Member lack 

grading and stratification, and only a few are inbricated. Similar conglomerates have been described in

MOSELEM MEMBER

The Moselem Member of the Virginville Formation is herein defined as the 230-m-thick sequence of 

cleaved black and green mudstone and shale and variable amounts of carbonate rock best exposed along 

Maiden Creek north of Moselem and in the southern 

half of the Hamburg quadrangle. The Moselem is tectonically overlain by the Sacony and Onyx Cave 

Members. The unit differs from the Onyx Cave in that 

it contains more shale and mudstone and less carbonate 

rock. The carbonate rocks within the Moselem are 

grossly similar to those of the Onyx Cave. Alterman 

(1972) referred to the rocks of the Moselem as the 

"Black-Slate" unit, although she placed them in the 

same lithotectonic unit as the Windsor Township 

Formation of the present study.

In addition to the shale and mudstone described in 

more detail below, the unit also contains very thin to 

thinly bedded lime mudstone and micrite interbedded 

with argillaceous limestone to shale. The ribbon limestone of the Moselem Member, like that of the Onyx 

Cave Member, displays parallel to ripple lamination 

in some beds, whereas other beds show only sparse 

graded bedding. Slumped horizons are common and 

suggest a lower slope environment.
STRATIGRAPHY AND SEDIMENTOLOGY 21

Sequences of thinly interlaminated black (Nl) to 

dark-gray (M>) graphitic shale and dark-yellowishorange (WYR 6/6) to pale-yellowish-orange (WYR 

8/6) dolostone and calcisiltite are locally present. 

These sequences are, in some places, highly contorted 

and suggest some type of soft sediment deformation 

(fig. 24).

Carbonate-clast conglomerates within the Moselem Member are generally thinner than those in the 

Onyx Cave Member. In addition, the average clastmatrix ratio is somewhat lower in the conglomerates 

of the Moselem than that in the Onyx Cave.

Mudstone and shale, locally well cleaved, are the 

dominant rocks of the Moselem Member (fig. 25). 

Alterman (1972) noted the extreme variability of these 

rocks and attempted to divide them into mappable 

units. In the western part of the Kutztown quadrangle 

and the eastern part of the Hamburg quadrangle, the 

Moselem consists of thin- to thick-bedded, graphitic, 

grayish-black (7V2) mudstone and shale interbedded 

with dusky-brown (5YR 2/2) mudstone or claystone 

and locally ribbon limestone. Lenses rich in pyrite and 

as much as 18 cm long occur at places. The weathering 

of the pyrite gives the rock an orange-tan color. Other 

lithologies within the member include thin- to thickbedded, grayish-black (N2) dolostone interbedded with 

medium-dark-gray (7V4) to medium-gray (N5) mudstone and light-gray (N7) siliceous shale.

FIGURE 24. Contorted beds in interlaminated black shale and 

orange dolostone of the Moselem Member. Width of field is 

approximately 7 cm. Roadcut approximately 640 m north of 

Virginville, Hamburg quadrangle.

FIGURE 25. Well-bedded, dark-gray mudstone and shale of the 

Moselem Member. Exposed in a quarry approximately 915 m 

northwest of Virginville, Hamburg quadrangle. Hammer for 

scale.

In the western part of the Hamburg quadrangle, 

the dominant rock type is dark-gray (N3) to darkgreenish-gray (5G 4/1) siliceous argillite, which contains lenses and discontinuous beds of chert. Thinbedded, very light gray (MS) quartzite is interbedded 

with mudstone and shale locally. Pyrite nodules are 

extremely common in this rock and discolor it upon 

weathering.

The stratigraphic complexity of the Moselem 

Member probably results from the intertonguing of 

the different shales, mudstones, and carbonate rocks. 

Carbonate rocks are not restricted to any specific shale 

type but seem to be more commonly associated with 

the darker shales and mudstones rather than with the 

green varieties.

AGE AND CORRELATION

The age of the Virginville Formation is not known 

for certain. Recent conodont collections from the
22 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

Moselem and Onyx Cave Members (J. E. Repetski, 

written commun., 1978, 1979, 1980) suggest a Late 

Cambrian to late Early Ordovician (Arenigian) age 

(fig. 26). These rocks, therefore, are coeval with some 

of the bodies of chert, limestone, and variegated shale 

of the Windsor Township Formation. They are also 

coeval with parts of the Allentown Dolomite and 

Beekmantown Group of the Lehigh Valley sequence. 

The Virginville Formation cannot be correlated 

lithologically with any of the units of the Lehigh Valley 

sequence. Parts of the Virginville do resemble the 

Araby Formation and parts of the Frederick Limestone of the Frederick Valley, Md. (Reinhardt, 1974, 

1977). More specifically, the Sacony Member resembles the Araby Formation. Reinhardt (1974, p. 7) described the Araby, the Antietam Quartzite of Jonas 

and Stose (1938). as a "buff to tan or green siliciclastic 

rock unit" in which "bedding is poorly defined."

FIGURE 26. Age relations between the Lehigh Valley sequence, the 

Windsor Township Formation, the Virginville Formation, and 

the Jutland klippe. Age data from Bergstrom and others (1972), 

Epstein and Berry (1973), Wright and others (1978), Perissoratis and others (1979), and J. E. Repetski (written commun., 

1978, 1979, 1980).

The Onyx Cave Member is lithologically similar to 

the lower member of the Frederick Limestone, the 

Rocky Springs Station Member (Reinhardt, 1974, 

1977) that conformably overlies the Araby Formation, 

whereas the Moselem Member has no lithologic counterparts in the Frederick Valley.

Despite the strong lithologic comparisons of the 

Frederick Valley sequence and parts of the Virginville 

Formation, a direct biostratigraphic correlation is 

lacking. In fact, the limited amount of faunal data 

collected from the Virginville suggests that the rocks 

of the Virginville are younger than the rocks of the 

Frederick Valley sequence.

ENVIRONMENT OF DEPOSITION

Stratigraphic and sedimentologic studies of the 

Virginville Formation indicate that the formation can 

be described as a slope and toe-of-slope deposit and 

probably part of an upward-shallowing sequence. 

Reinhardt (1974, 1977) envisioned the same paleoenvironment for the Araby Formation and the Frederick 

Limestone of Maryland. Study of the Sacony Member 

of the Virginville Formation suggests that the Sacony 

was deposited in a low-energy clastic basin below 

wave base, similar to the environment suggested by 

Reinhardt (1974) for the Araby. The strained quartz 

and minor, but conspicuous, amounts of microcline 

and plagioclase as framework constituents are indicative of derivation from a plutonic-metamorphic source, 

with some input from sedimentary rocks in the form of 

chert, and not from a volcanic source as suggested by 

Alterman (1972). Reinhardt (1977), on the basis of 

geochemical evidence, suggested a westerly cratonic 

source for the Araby. For reasons explained below, 

however, a southeasterly cratonic source is proposed 

for the Sacony Member.

The transition from the siliciclastic rocks of the 

Sacony Member to the carbonate rocks of the Onyx 

Cave Member, a slope deposit, is abrupt. The Onyx 

Cave consists of thin-bedded ribbon limestones and 

thinly interlaminated black shale and dolostone suggestive of deposition in a quiet slope or toe-of-slope 

environment below wave base. The carbonate-clast 

conglomerates and thick, massive calcarenites indicate periodic influxes of material related, in part, to 

local slumping on the otherwise quiescent slope. Keith 

and Freidman (1977) have described a similar type of 

slope and toe-of-slope sequence from the Taconic region 

of New York.

Mcllreath and James (1978) have developed two 

facies models for carbonate slopes on the basis of the 

rock record and modern environments. The models 

are (1) depositional margins typified by slopes that are 

gentle and decrease in inclination basinward and (2)
STRATIGRAPHY AND SEDIMENTOLOGY 23

bypass margins characterized by a margin atop a cliff 

or submarine escarpment. The main difference between the two models is that, in bypass margins, material is transported directly from the shallow-water 

shelf to a deepwater environment, thus bypassing a 

large part of the slope; in the depositional margin, 

however, shallow-water material may not reach the 

middle or lower part of the slope because of the gentle 

inclination. In addition, the nature of the slope sediments are, in part, dependent upon whether the 

shallow-water margin is formed (1) by lime sands or 

(2) by reefs and associated reef material. The rock types 

and sedimentary structures indicate that the rocks of 

the Onyx Cave Member of the Virginville Formation 

were deposited on a depositional margin dominated by 

lime and quartz sand. The lack of reef-derived clasts 

and fossils and the presence of well-rounded quartz 

and carbonate grains support the depositional margin 

model, as opposed to the bypass margin model. Other 

evidence includes slope-derived carbonate-clast conglomerates, massive to graded calcarenite, paralleland cross-laminated peloidal calcarenite, and slumped 

ribbon limestone (fig. 27 and Mcllreath and James, 

1978).

Mcllreath and James (1978) pointed out that none 

of the slope facies are mutually exclusive, and, as such, 

the rocks of the Onyx Cave Member may have originated on a depositional margin characterized, in part, 

by reefs. In this case, the reef-derived material would 

not have traveled far enough downslope to become 

incorporated in the rocks of the Onyx Cave or Moselem 

Members. Nevertheless, the main body of evidence 

points to a margin characterized by lime and quartz 

sand and not reefs.

Analysis of the Moselem Member suggests that 

the Moselem can be interpreted as a toe-of-slope facies 

and probably a distal equivalent of the Onyx Cave 

Member (fig. 27), although the Moselem is now in fault 

contact with the latter. In addition, the Moselem 

probably interfingers with the Onyx Cave, as suggested by the presence of rock types common to each 

unit. Local slumped horizons and carbonate-clast conglomerates in the Moselem attest to a lower slope or 

toe-of-slope environment, although movement can 

occur on slopes as low as 4° (Lewis, 1971).

The carbonate rocks of the Virginville Formation 

were deposited by several different depositional 

mechanisms. Hemipelagic sedimentation and dilute 

turbidity currents probably resulted in deposition of 

the ribbon limestone. The rhythmic sequences of lime 

mudstone and black shale are suggestive of deposition 

by turbidity currents (Wilson, 1969). The sequences 

may be overbank levee deposits associated with the 

emplacement of the thick calcarenites and carbonateclast conglomerates.

The random orientation of clasts, clasts "floating" 

in matrix, poor sorting, and lack of grading are suggestive of some type of viscous debric flow mechanism 

(Johnson, 1970; Cook and Taylor, 1977; Hampton, 

1972). In addition, plug flow (Johnson, 1970; Shanmugan and Benedict, 1978) is indicated by the clasts that 

project through the top of beds.

Recently, Krause and Oldershaw (1979) have developed a two-layer sediment gravity flow model to 

explain the presence of turbidite caps on conglomerate 

beds. The few conglomerate beds of the Onyx Cave 

Member that are capped by turbidites can be classified as stratified disorganized beds and are interpreted 

to result from deposition farther downslope than the 

beds that lack the turbidite caps (Krause and Oldershaw, 1979) or the disorganized beds. Hampton (1972) 

and Krause and Oldershaw (1979) attribute the stratified cap to turbidity currents that develop on top of the 

main mass of sediment. Material in front of the flow is 

sheared backwards and on top of the moving mass 

creating turbulence.

The conglomerates probably result from translational and rotational slides (Cook, 1979). The lack of 

the turbidite caps on the majority of conglomerates 

suggests that the sediment mass did not move far from 

its source. The local origin of the conglomerates is 

further supported by the clasts being of deepwater 

rather than shallow-water carbonate rocks. The importance of this relation was noted by Cook and Taylor 

(1977). Thus, the carbonate-clast conglomerates probably originated in a slumped interval in which the 

sediment shear strength was exceeded, causing the 

mass to become mobile, break up, and become a debris 

flow. Although all clasts are locally derived, no conglomerate could be traced backward to an obvious 

slump or slide.

The mechanism of deposition of the planar- to 

current-ripple-laminated black shale and yelloworange dolostone and calcisiltite is not fully understood but may be the result of contour-following currents that redistributed previously deposited material.

The carbonate rocks were apparently deposited 

by a continuum of depositional mechanisms that were 

in operation on the slope. That is, the mechanisms 

were operating together such as do dilute turbidity 

currents related to emplacement of massive grain 

flows, or in opposition, such as do contour currents 

reworking and redistributing detritus deposited by 

dilute turbidity currents and debris flows.

In summary, then, the Sacony Member of the Virginville Formation was deposited in a low energy siliciclastic basin below wave base. The transition of the 

Sacony Member to the Onyx Cave Member, the slope
24 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

NW

ONYX CAVE AND MOSELEM MEMBERS 

Ribbon limestone 

Graded to massive calcarenite 

Slumped hemipelagic rocks 

Limestone conglomerate

liTTTii Black and green hemipelagic mudstone and argillite

SACONY MEMBER 

Siliciclastic rocks

Shale and mudstone

FIGURE 27. Facies diagram for the Sacony, Onyx Cave, and Moselem Members of the Virginville Formation. Stratigraphy is idealized and 

is in no way intended to imply specific horizon locations or thickness; the diagram is meant only to illustrate the proposed distribution of 

rock types.

facies, indicates the development and progradation of 

a carbonate shelf and slope. This slope is interpreted as 

a depositional rather than a bypass slope.

PALEOGEOGRAPHY

The facing direction of the slope recorded by the 

rocks of the Virginville Formation is not known for

certain. Some information concerning the direction of 

slope can be obtained by analysis of slump folds in the 

Onyx Cave Member and tectonic folds along the fault 

separating the Onyx Cave and Sacony Members from 

the Moselem Member.

The orientation of fold axes, axial planes, and 

bedding in slumped rocks has been used to determine
STRATIGRAPHY AND SEDIMENTOLOGY 25

gravity transport direction (Hansen, 1967; Corbett, 

1973; Hall, 1973; Stone, 1976). In addition, fold axes 

and fold vergence have been used to determine movement directions in tectonic folds (Moore and Wheeler, 

1978; Wheeler, 1978). All of these studies employed a 

method of fold analysis developed by Hansen (1967, 

1971) in which the slip or slump movement plane and 

direction of movement within this plane, the slip line, 

of a slump or tectonic sheet could be obtained by plotting the axes and sense of vergence of asymmetric 

folds on a stereo net. The investigations cited above 

and numerous others have shown that this method is 

useful in paleogeographic reconstructions and, therefore, is suited to the present study.

Excellent exposures of slump folds in the Moselem 

Member of the Virginville Formation can be found 

along the Reading Railroad grade approximately 1.2 

km southwest of Shoemakersville in the Temple quadrangle (fig. 28). The absence of cleavage and joints that 

are generally related to tectonic folds of the area, the 

truncation or beveling of some of the folds by overlying 

undeformed beds, and the general restriction of 

deformation to a single bed are suggestive of a softsediment origin of the folds. Slip-line analysis of these 

folds (fig. 29) indicates that mass movement, probably

FIGURE 28. Soft-sediment folds in ribbon limestone of the Moselem 

Member. Folds verge to the northwest (right). The layer of 

limestone pull-aparts attests to the unconsolidated nature of 

some of the sediments. Exposure along the Reading Railroad 

grade approximately 1.2 km southwest of Shoemakersville, 

Temple quadrangle. Hammer for scale.

by translational sliding, occurred on slopes that were 

inclined to the northwest.

Fault-related folds at the contact of the Moselem 

Member of the Onyx Cave and Sacony Members are 

characterized by overturned flexural-slip folds. These 

folds are always associated with an autoclastic melange 

that is restricted to the fault zone and thereby suggest 

a tectonic origin for the folds. Although a good amount 

of azimuthal scatter of the data occurs (fig. 30), analysis of the vergence of these folds indicates northwest 

transport of the upper plate containing the more 

"proximal" Onyx Cave Member over the more "distal" 

Moselem Member. In other words, the rocks of the 

Onyx Cave Member were deposited to the southeast of 

the rocks of the Moselem Member.

In summation, analysis of the tectonic and slump 

folds in the Virginville Formation indicates that (1) 

extensive remobilization of semiconsolidated to unconsolidated sediments occurred by translational sliding 

on slopes that were inclined to the northwest and (2) 

the more proximal carbonate slope rocks (Onyx Cave

Slip-line direction 

N. 30° W.

EXPLANATION

 Pole to average bedding plane

-» Pole to slip plane

FIGURE 29. Soft-sediment fold axes (dots), fold vergence (semicircular arrows), calculated slip plane (dashed girdle), and 

slip-line orientation of slump folds in the Moselem Member 

along the Reading Railroad grade 1.2 km southwest of Shoemakersville, Temple quadrangle.
26 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

Slip-line direction 

N. 18°W.

FIGURE 30. Fold axes (dots), vergence (semicircular arrows), and 

slip-line orientation of tectonic folds related to thrusting along 

the fault separating the Onyx Cave and Sacony Members and 

the Moselem Member.

Member) were thrust to the northwest over their basinal equivalent (Moselem Member), indicating that the 

rocks of the Onyx Cave Member were deposited to the 

southeast of the rocks of the Moselem Member

The rocks of the Virginville Formation may be a 

remnant of a sequence of carbonate slope and rise 

sediments that were deposited adjacent to a shallowwater carbonate shelf. This shelf may have formed on 

a topographic high or microcontinent to the southeast 

of North America. The rocks of the Virginville Formation may have been deposited on the northwestfacing bank of the microcontinent concomitant with 

shelf sedimentation on the southeast-facing slope of 

the North America craton. Thus, the Virginville Formation may represent a rock-stratigraphic, if not timestratigraphic, equivalent of the Frederick Valley 

sequence, which was deposited on a southeast-facing 

slope (Reinhardt, 1974, 1977).

STRUCTURE

The part of the central Appalachians of the present study is divisible into three structural terranes,

each characterized by a unique sedimentary history 

and, to a lesser extent, different structural styles. 

These terranes are the Valley and Ridge province in 

which the Upper Ordovician(?) to Lower Silurian 

Shawangunk Formation and younger rocks are exposed, the allochthonous Hamburg klippe consisting 

of the Greenwich and Richmond slices, and the parauthochthonous Lehigh Valley sequence of the Reading 

Prong nappe megasystem. The latter two are important to the present study, and their deformation is 

described below.

ROCK FABRIC

The rocks of the Lehigh Valley sequence and of the 

Hamburg klippe were folded during three main phases. 

The first fold phase (Fj) is marked by east-northeasttrending isoclinal to open, asymmetric to symmetric 

folds of various wavelengths and amplitudes. Axial 

planar slaty cleavage (SJ is well developed in the rocks 

of the Lehigh Valley sequence and locally in the less 

competent rocks of the Richmond slice of the Hamburg klippe. In contrast, the rocks of the Greenwich 

slice of the Hamburg klippe lack the well-developed 

slaty cleavage and are, instead, characterized by a 

"scaly" type of cleavage that is discussed in more detail 

on page 27.

The second fold phase (F2) is characterized by 

northeast-trending, parallel, symmetric to asymmetric, generally open folds of outcrop scale to small crenulations. A well-developed fracture and strain-slip or 

crenulation cleavage (S 2) has formed in response to 

folding. In some areas, earlier F2 parallel folds were 

flattened, with resultant thickening of the fold hinges 

and development of a south-dipping fracture cleavage 

that fans the folds. F2 structures are well developed in 

all rocks of the eastern end of the Hamburg klippe.

The latest fold phase (F3) is only locally developed. 

It is characterized by east-northeast-trending kink 

folds, small (meter-scale) open folds, and crenulations.

Detailed structural analysis indicates that the 

rocks of the Lehigh Valley sequence have been folded 

by all three fold phases. In contrast, ongoing studies of 

the Upper Ordovician to Silurian rocks of the Valley 

and Ridge northeast of Hamburg indicate that only 

the F2 and F3 fold phases are recorded by these rocks. 

This suggests, then, that the F] fold phase is related to 

a pre-Silurian (Taconic?) erogenic event and the F2 

and F3 folds are related to post-Silurian (Alleghanian) 

events. Additional evidence for the pre-Silurian fold
STRUCTURE 27

phase is (1) the apparent unconformable relations that 

exist between the steeply dipping allochthonous rocks 

and the overlying near-horizontal Upper Ordovician 

Spitzenberg Conglomerate (Whitcomb and Engel, 

1934) north of Lenhartsville and (2) the exposed angular unconformity and de'collement between the Shawangunk Formation and the Hamburg klippe at 

Schuylkill gap.

FAULTS

Low-angle thrust faults dominate the complex 

structure of the eastern part of the Hamburg klippe. 

The parautochthonous Lehigh Valley sequence is separated from the Hamburg klippe by the Kutztown 

thrust (fig. IB), a gently southeast-dipping thrust 

fault that has cut numerous early faults within the 

Lehigh Valley sequence. MacLachlan (1979), working 

in the Temple and Fleetwood quadrangles (fig. IB), 

referred to the Kutztown thrust as the Leinbachs 

thrust and maintained that it dips gently to the north 

with the Lehigh Valley sequence thrust beneath the 

klippe. However, the conspicuous occurrence of northdipping beds located along the trace of the fault about 

3 km southeast of Virginville suggests that the Lehigh 

Valley sequence moved .to the northwest over the 

allochthon, thereby dragging rocks that originally 

dipped south into north-dipping attitudes. The evidence suggests that the fault dips south in this area.

The Hamburg klippe is separated from the rocks 

of the Shochary Ridge sequence by the Kistler Valley 

fault, a steep southeast-dipping upthrust (Lyttle and 

Drake, 1979). On the basis of paleontologic evidence, 

Wright and others (1978, 1979) have questioned the 

presence of this fault and have, instead, suggested a 

depositional contact between the two sequences of 

rocks. This interpretation cannot explain the faultrelated deformation along the Kistler Valley fault 

(Lyttle and Drake, 1979). In addition, mapping in the 

Shawangunk Formation north of Hamburg (Lash, 

1980b) suggests that the Kistler Valley fault continues 

west into the Silurian clastic rocks north of Lenhartsville where movement on the fault has resulted in 

bedding discordancies in the rocks.

The fault separating the Richmond slice from the 

Greenwich slice of the Hamburg klippe is not exposed 

but is inferred from both the highly contrasting styles 

of deformation (discussed on p. 26) and the vastly 

different sedimentologic characteristics of the two 

slices. Additional evidence in support of the thrust 

contact of the two allochthonous slices can be found in 

exposures along the Reading Railroad grade 1.5 km

west of Shoemakersville in the Hamburg quadrangle. 

At this locality, slices of Middle Ordovician (Nemagraptiis gracilis graptolite zone) rocks of the Windsor 

Township Formation are found associated with larger 

slices of Lower Ordovician (Arenigian) ribbon limestones of the Moselem Member of the Virginville 

Formation. The tectonic slices of the Windsor Township rocks apparently represent slices of underlying 

rock detached and dragged (technically mixed?) into 

present position during emplacement of the Richmond 

slice much in the same way as the tectonic slices of the 

Stockbridge Formation of the Taconic Range were 

dragged along the sole of the allochthonous Everett 

Formation (Zen and Ratcliffe, 1966).

STYLE OF DEFORMATION

As described on page 26, the rocks of the Windsor 

Township Formation in the Greenwich slice lack the 

well-developed slaty cleavage of the equally incompetent Martinsburg Formation and Jacksonburg Limestone. Instead, they exhibit a "scaly" cleavage characterized by a poorly developed fracture cleavage that 

consists of a group of intersecting fracture planes. 

Cowan (1974) has referred to this type of cleavage as a 

"penetrative shear-fracture fabric" apparently produced by localized losses of resistance at geologically 

high strain rates (Raymond, 1975a), for example, 

strain rates typical of subduction complexes.

Without going into the details of melange nomenclature (for discussion see Berkland and others, 1972; 

Raymond, 1975a, b; Beutner, 1975), Cowan's (1974) 

term "tectonic melange" will be used to describe the 

rocks of the Greenwich slice. The term "tectonic 

melange" as defined by Cowan emphasizes that the 

melange records a deformation without regard to 

types of inclusions or even the presence of inclusions.

The main internal feature typical of tectonic 

melanges as described by Cowan is the pervasive, 

mesoscopic shear fracture. In the Greenwich slice, the 

shear fractures in the less competent argillaceous 

rocks result in a scaly appearance in which individual 

chips are polished and slickensided. Because of relative 

differences in competency, the rocks take on a very 

chaotic appearance upon deformation and are characterized by lentils or phacoids of more competent rocks 

embedded in a sheared matrix of less competent material (fig. 31). This phenomenon is best illustrated in the 

rocks of the Greenwich slice by zones of intense strain, 

here referred to as deformation zones, marked by 

small pull-apart (fig. 32) and small- to large-scale 

pinch-and-swell (fig. 33) structures.
28 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

FIGURE 31. Large boudin or phacoid of graywacke embedded in a 

sheared pelitic matrix. Width of boudin is approximately 2.5 m. 

Roadcut along: Route 143 approximately 360 m west of Albany. 

Kutztown quadrangle.

Outside the deformation zones, the less competent 

mudstone shows the penetrative shear-fracture fabric, 

and individual sandstone beds are essentially undeformed, although some beds are displaced along fractures at low angles to bedding. Disruption continues to 

increase in intensity toward the deformation zone 

until only isolated phacoids of beds surrounded by a 

completely sheared argillite matrix remain. This progressive style of deformation has been described from 

the Garzas tectonic melange of the Franciscan Complex by Cowan (1974). In addition, Hamilton (1979) 

noted a back-and-forth gradation in disruption, with 

increasing shearing into a fully developed melange 

characterized by abundant lenses and blocks, on 

Timor Island.

In his study of tectonic melanges. Cowan (1974) 

discussed the importance of determining the parentage of the melange. He noted that, although the position of an inclusion may now be relatable to surfaces of 

shear, the presence of the inclusion itself may have 

resulted from chaotic submarine slumps and not from 

tectonic mixing. Within the Windsor Township ForFIGURE 32. Small graywacke boudin embedded in a highly sheared 

pelitic matrix. Note scaly cleavage or "penetrative shearfracture fabric" (Cowan, 1974) of the pelitic matrix. A late 

subhorizontal northwest- (right-) dipping fracture cleavage 

cuts both matrix and boudin. Roadcut along Route 143 approximately 360 m west of Albany, Kutztown quadrangle. Lens cover 

for scale.

mation, "exotic" inclusions are represented by the 

Lower Ordovician chert, limestone, and variegated 

shale units. These inclusions were probably emplaced 

as subaqueous gravity slides into Middle Ordovician 

flysch prior to melange deformation of these rocks. 

This distinction is a very important point in the final 

tectonic synthesis.

The development of the tectonic melange fabric in 

the rocks of the Greenwich slice occurred prior to F! 

folding of the allochthon and parautochthon. This 

relation is illustrated in the Albany area and the area 

south of Dreibelbis, where individual deformation 

zones have been mapped around F, folds.

As noted on page 14, the Greenwich slice is lithologically similar to the Summerdale allochthon of Root 

and MacLachlan (1978) at the western end of the 

Hamburg klippe. This correlation is further supported
STRUCTURE 29

FIGURE 33. Pinch-and-swell structure. The more competent graywacke has deformed brittlely, whereas the less competent pelite 

has flowed around the graywacke. Roadcut along Route 143, 

approximately 360 m west of Albany, Kutztown quadrangle. 

Notebook in lower left corner for scale.

by the similar deformational styles of the two allochthons. Root and MacLachlan (1978) noted that rocks of 

the Summerdale allochthon have characteristics of a 

"highly sheared melange." The implication of the 

correlation from the eastern end of the Hamburg 

klippe to the western end is that the lower lithotectonic 

units of the Hamburg klippe are characterized by a 

slice or slices of chert, limestone, and variegated shale. 

The chert, limestone, and variegated shale slices are 

tectonically overlain by a highly sheared graywackeshale slice that contains olistoliths of rocks similar to 

that in the underlying slice. These slices are in turn 

tectonically overlain by slices such as the Richmond 

slice.

PLATE TECTONIC IMPLICATIONS

Many plate tectonic models have been proposed to 

explain the complex geology of the Appalachian orogen from Newfoundland to Georgia (Bird and Dewey, 

1970; Glover and Sinha, 1973; St. Julien and Hubert, 

1975; Thomas, 1977; Hatcher, 1978; Osberg, 1978; 

Schenk, 1978). All of these workers agree upon the 

closing of a proto-Atlantic ocean and associated subduction and obduction that resulted in the Taconian 

and Acadian orogenies. From the combined structural, sedimentologic, and stratigraphic data obtained 

in this study, a conceptual plate tectonic model for the 

early Paleozoic of this part of the central Appalachians 

is described below.

The proposed tectonic model (fig. 34) involves the 

aborted subduction of the North American Continent 

beneath a southeastern microcontinent. Tectonic 

models based on the abortive subduction of the continental margin have been suggested by other geologists 

for the northern and maritime Appalachians (Chappie, 1973; McBride, 1976; Hiscott, 1978; Stanley and 

Ratcliffe, 1979).

Late Proterozoic rifting in response to opening of 

the proto-Atlantic ocean resulted in the formation of a 

marginal basin separating the North American Continent from a microcontinent to the southeast (fig. 34A). 

The rifted blocks or microcontinents may be represented by such Precambrian complexes as the Fordham Gneiss terrane, Baltimore Gneiss terrane, Pine 

Mountains, eastern Great Smokey Mountains, and the 

Sauratown Mountains (Rankin, 1975; Thomas, 1977).

The Early Cambrian of the Appalachians was 

characterized by the formation of a stable carbonate 

platform on both the North American Continent 

(Rodgers, 1968) and the microcontinent (Thomas, 1977) 

(fig. 34^4). Development of the shelf on the North 

American craton is evidenced by the Frederick Valley 

sequence of Maryland interpreted by Reinhardt (1974, 

1977) to be part of the southeast-prograding carbonate 

shelf. In addition, the Cambrian and Ordovician carbonate rocks of the Pennsylvania Great Valley attest to 

the vast amount of shallow-water carbonate sedimentation during the lower Paleozoic on the North American Continent. Shallow-water shelf sediments on the 

microcontinent may be represented by such sequences 

as the Setters Formation and Cockeysville Marble 

associated with the Baltimore Gneiss or the lower 

Inwood Marble associated with the Fordham Gneiss. 

Carbonate rocks of the Virginville Formation of the 

present study were deposited on a northwest-facing 

bank and record maturation of a stable carbonate 

platform to the southeast, probably a microcontinent.

Shelf deposition and coeval deepwater sedimentation continued into Ordovician time. Some units of the 

Windsor Township Formation, variegated shale and 

mudstone and chert and limestone, represent deepwater pelagic sediments deposited concomitant with
30 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

A. Proterozoic Z to Early Cambrian. Rifting resulted in the separation of North America and a microplate located to the southeast, 

perhaps, represented by the Baltimore Gneiss terrane (Thomas, 

1977). The separating basin was not very extensive and was 

probably underlain by thinned continental crust as rifting 

never progressed beyond the intracontinental phase and the 

major rift center formed to the east of the microplate. The lack

of ophiolite debris in the flysch sequences of the Appalachian 

Great Valley in Pennsylvania precludes the development of extensive oceanic crust. Rocks of the Richmond slice of the Hamburg 

klippe were deposited on the northwest-facing lower slope of a 

passive continental margin on the microplate while coeval carbonate shelf deposits (Allentown Dolomite, Conococheague Group, for 

example) were deposited on the shelf of the North American craton.

NW

SEA LEVEL -North American shelf

+ + +

+ + + + + + + 

4- + + Rifted microplate 4- 

+ + + + + + + + 

+ x + + 4- + + + + + +

+

+ + + + +' +

+ + + + + + 

+ +North American craton +

SE

Early

Cambrian

B SEA LEVEL

Longitudinally derived Lower (?) to Middle

Ordovician clastic sediments and Lower to

Middle (?) Ordovician pelagic sediments

+ + + + + + + +

4- 4- 4- + 4- Peripheral bulge 

EXPLANATION

Richmond 

slice-_ ^

'"*"* + 4

+ + + +

444 + + to Middle 

+ + + + Ordovician

+ +

Late 

Cambrian

4

4- 4

Gneiss, granite

Limestone

Sandstone

Shale

Shaley limestone

B. Late Cambrian to Middle Ordovician. Subduction was probably dispersal of pelagite in Early Ordovician time followed by coarseinitiated by Early Ordovician time. Red and green shale of grained clastic sediment in Middle Ordovician time that was shed 

Early Ordovician age in the Greenwich slice reflects the uplift longitudinally from an uplifted area to the northeast. These clastic 

of a terrigenous source area. This uplift may record a collision rocks were deposited as abyssal plain turbidites (Stewart, 1976; 

at the New York Promontory that resulted in the longitudinal Dickinson, 1982).

FIGURE 34. PLATE TECTONIC MODEL FOR THE HAMBURG KLIPPE
PLATE TECTONIC IMPLICATIONS 31

C. Blackriveran. As the North American plate approached the slice continued to be supplied from a northeasterly source. These

trench, it was flexed upward resulting in rapid uplift and ero- sediments (clastic rocks stratigraphically overlying older pelagic

sion of the shelf carbonates at the southeastern margin of the sediments) were accreted onto the hanging wall of the trench. The

North American craton. Clastic sediments of the Greenwich Greenwich slice is part of this accretionary prism.

NW Lehigh Valley 

sequence

SE

.Black River hiatus SEA LEVEL

Accretionary prism 

(Greenwich slice)

Blackriveran

Black River hiatus

Lehigh Valley 

sequence

Lehigh Valley 

sequence^ SEA LEVEL

Martinsburg . , Formation Greenwich

RocklandianKirkfieldian

D. Rocklandian-Kirkfieldian. Rocklandian to Kirkfieldian time was 

characterized by deposition of the Jacksonburg Limestone during rapid basin subsidence. This concept is supported by the 

lithostratigraphic changes from the "cement-limestone" facies 

to the "cement-rock" facies of the Jacksonburg and by the transition from the shallow, warm-water North Atlantic province 

conodont fauna at the base of the Jacksonburg to the deep, 

cold-water North Atlantic fauna at its top. The basin probably 

formed by normal faulting in response to "trench suction" 

(Elsasser, 1971) rather than by tectonic loading at the continental margin. Deposition of the clastic rocks of the Martinsburg Formation was probably initiated at the end of Kirkfieldian time (all 

contacts are probably time transgressive). By this time, subduction 

had ended, and the closure of the Jacksonburg-Martinsburg basin 

was probably accomplished by reactivation of the early formed 

normal faults into thrust faults. The nappes of the Pennsylvania 

Great Valley and New Jersey were probably formed in this manner. 

After the Hamburg klippe was emplaced, it became a passive rider 

on the stacked nappe sequence. At this time of extreme compression, 

the Richmond slice was emplaced onto the Greenwich slice.

FIGURE 34.-PLATE TECTONIC MODEL FOR THE HAMBURG KLIPPE-Continued
32 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

E. Edenian. By Edenian time, the uplifted area related to the pro- tion. This uplift occurred as the tectonic wave was built up by the

posed collision at the New York Promontory had migrated accretion of basement rocks and overlying miogeoclinal sequences

laterally and closer to the Martinsburg basin of southeastern (nappes). The nappes continued to move by reactivation of the early

Pennsylvania and was now supplying the coarse clastic sedi- formed normal faults into thrust faults, and the basin continued to

ment of the Ramseyburg Member of the Martinsburg Forma- close.

NW

SEA LEVEL

SE

Black River hiatus

Hamburg klippe

 ^

Greenwich

.slice ..Richmond 

_/ / slice North American flank

+ Lehigh ValleyM- + + + 4.4.

-l- sequence 4-4-4-4-4.4.4.4. Lehigh Valle 

4.4-4.4-4. sequence

4- Crystalline-cored nappes 4

Edenian 

(C. Spiniferus)

Hamburg klippe

SEA LEVEL

4- 4- 4- +

4- + 4- 4- /+ 

4. Muddy turbidites (Pen Argyi 4. 4.

+ Member of Martinsburg 4- 4- Lehigh Valley 

4- 4- Formation) 4-4-4-

Richmond 

slice

Early Maysviliian 

(Late C. Spiniferus)

sequence

4-4-4-4-4-4-4-4- 4-

'+ + + +~~~^f~---j^__+'~'^f~ Crystalline-cored nappes

+ + + + +"+ T -f -±____+ + + 

+ + + + + + + + + + + + + + + + + + + + + +

+ + + + + + + + + + + + 4-+__^ J =t 1= i + ±__ 

+ + + + + + + + + + + +^-~~~~~~~~~^ +

+ + + + + + + + + 

+ + + + + + +

+ + + + + + 

+ + + + +

+ +_

F. Early Maysviliian. By Maysviliian time, tectonic movement had Pen Argyl contains structures typical of muddy, slow-moving, low

slowed significantly. The source area was now lowered, and the concentrate turbidity current deposits, as described by Stow and

more compositionally mature clastic rocks of the Pen Argyl Shanmugam (1980), that suggest the progradation of a muddy

Member of the Martinsburg Formation were deposited. The shoreline.

FIGURE 34.-PLATE TECTONIC MODEL FOR THE HAMBURG KLIPPE-Continued
PLATE TECTONIC IMPLICATIONS 33

Early Ordovician shallow-water carbonate rocks of 

the Beekmantown Group.

Closing of the marginal basin was accomplished 

by southeast-dipping subduction beneath the microcontinent. Subduction, which was probably initiated 

in early Early Ordovician time, resulted in the foundering or depressing of the carbonate shelf (fig. 345). 

Evidence for foundering of the lower Paleozoic North 

American shelf has been documented in Newfoundland by Stevens (1970) and also may be documented in 

rocks of the Lebanon Valley sequence of the central 

Appalachian Great Valley. MacLachlan and others 

(1975) noted that, in the Lebanon Valley west of Womelsdorf, Pa., the uppermost Ontelaunee Formation 

is overlain conformably or paraconformably by the 

Annville limestone, a high-calcium limestone unit, 

of definite Chazyan age. The change from almost pure 

dolomite of the Ontelaunee to the high-calcium 

limestone of the Annville may represent a transgressive period that resulted from foundering of the shelf. 

Therefore, progradation of the shelf seems to have 

continued until at least Whiterockian time and probably into Chazyan time. Progradation was followed by a 

period of transgression that resulted from foundering 

of the shelf in response to subduction and by deposition 

of rocks such as the high-calcium Annville Formation.

The style of deformation of the Greenwich slice of 

the present study and of the Summerdale allochthon of 

the western end of the klippe suggests that these rocks 

were deformed in a subduction complex and, therefore, represent trench sediments (fig. 345). Paleogeographic reconstructions based upon the stacking order 

of thrust sheets have been documented from numerous 

areas (Williams, 1975; Elliot, 1976) and may be applied 

to the rocks of the Hamburg klippe. If northwest 

transport during closing of the marginal basin can be 

assumed, the stacking order of the slices in the western 

end of the Hamburg klippe suggests that the abyssal 

sediments of the Enola allochthon were northwest of 

the rocks of the Summerdale allochthon and, by correlation, the Greenwich slice. In other words, the abyssal 

sediments were deposited to the northwest of the subduction zone.

Sparse directional paleocurrent data evince both 

northwesterly and southeasterly sources, but, as stated 

earlier, analysis of slump folds supports a predominantly southeasterly source, possibly the microcontinent. Despite this evidence, some of the detritus may 

represent second-cycle sediments originally deposited 

as continental slopes and rise sediments adjacent to 

the southeast-facing shelf.

As subduction continued, the older abyssal sediments, represented by the bodies of red and green 

shale and accompanying rocks, became detached from

the underlying plate and slid into the trench. Moore 

(1975) maintains that physical properties such as density and yield strength of clastic sediments (that is, 

hemipelagic and pelagic mud and red and brown 

clays) and the underlying biogenic sedimentary unit 

diverge with time; however, the same physical properties of the biogenic unit and the underlying upper 

basaltic layer of oceanic crust converge. This difference is significant in that the low density of the clastic 

sediments and resultant relative buoyancy would tend 

to favor the incorporation of these sediments into the 

trench sediments at shallow levels, presumably by 

slumping or sliding along a de'collement separating 

the physically contrasting units (Moore, 1975). As the 

abyssal sediments approached the trench, the more 

buoyant red and green mudstone and shale units 

became detached and were incorporated into the shallow levels of the trench sediments in a manner similar 

to that described above. The great amount of soft sediment deformation in some of these units attests to 

slumping and sliding during emplacement. Following 

emplacement of these units, the rocks were severely 

sheared and strained resulting in the tectonic melange 

style of deformation.

Root and MacLachlan (1978) maintain that the 

Enola and Summerdale allochthons were closely associated and were likely emplaced together from the 

same general source. Their assertion appears likely in 

that during subduction a large mass of pelagic sediments represented by the Enola allochthon became 

detached from the underlying plate along the de'collement separating the younger clastic sediments from 

the underlying units. This slice was accreted to the 

trench sediments, and the entire mass moved as a unit. 

It is possible, but difficult to prove at the present level 

of erosion, that detachment and accretion occurred 

several times prior to emplacement of the klippe onto 

the shelf. The majority of turbidite and grain flow 

deposits, as well as the olistoliths of pelagic and 

hemipelagic sediments, were emplaced during Chazyan time, essentially concomitant with foundering of 

the shelf.

As the North American craton approached the 

trench, the inability of the buoyant continental crust to 

subduct beneath the microcontinent resulted in uplift 

of the continental margin. Erosion of the shelf and 

continental margin rocks accompanied uplift and is 

evidenced by the Black River hiatus in the Lehigh 

Valley sequence (see fig. 2) and the Lebanon Valley 

sequence that is somewhat different from the tectonically lower Lehigh Valley sequence (MacLachlan and 

others, 1975). The lack of a well-defined Black River 

hiatus in the Cumberland Valley sequence (Root, 1977, 

fig. 2), the tectonically lowest and probably the least
34 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

traveled sequence in the Pennsylvania Great Valley, 

indicates that the area of the shelf defined by the carbonate rocks of this sequence was not uplifted but, 

instead, remained submerged and developed an almost 

uninterrupted stratigraphic sequence. Therefore, the 

farther northwest one moves from the tectonic welt or 

arch, the smaller the unconformity becomes, until conformable or paraconformable relations are realized.

Uplift and erosion of rocks of the Beekmantown 

Group are evidenced by the presence of dolomite 

clasts, presumably derived from the Ontelaunee Formation of the Beekmantown Group, within the lower 

unit, the "cement limestone" facies, of the Jacksonburg Limestone in New Jersey (Drake, 1969) and the 

Hershey Limestone, a unit which closely resembles the 

upper "cement rock" facies of the Jacksonburg (MacLachlan, 1967), near Myerstown, Pa. (MacLachlan 

and others, 1975). The presence of the basal calcirudite 

unit containing clasts of Beekmantown-type dolomite 

indicates that uplift of the continental margin was in 

progress by Rocklandian time, concomitant with deposition of the Jacksonburg Limestone. The change from 

the relatively shallow-water "cement limestone" facies 

to the deeper water "cement rock" facies of the Jacksonburg Limestone of the Lehigh Valley sequence 

indicates that the basin continued to deepen during 

Rocklandian and Kirkfieldian time. Deposition of the 

deepwater psammitic-pelitic Martinsburg Shale followed.

The inability of the North American Continent to 

subduct beneath the microcontinent retarded and 

eventually stopped subduction and locked the two 

plates. As stress built up along the contact of the two 

plates, detachment of wedges or slabs of basement 

rock and associated miogeoclinal rocks occurred (fig. 

34Z>). The detached basement represents the cores of 

the carbonate nappes of the Pennsylvania Great Valley. Because the Jacksonburg Limestone was involved 

in nappe formation (Drake, 1978), detachment and 

imbrication probably started somewhat after deposition of the Jacksonburg, possibly in Late Blackriveran 

to Kirkfieldian time.

The technically telescoped and thickened continental crust resulted from large-scale underthrusting 

and imbrication of slabs or wedges of cratonic basement on easterly inclined faults or ductile shear zones 

(fig. 34Z>). Detachment of basement wedges during 

collisional tectonics has been described from the 

northern Appalachians by Stanley and Ratcliffe (1979) 

and Ratcliffe (1979). At this time of extreme telescoping, the Richmond slice (consisting of carbonate-slope 

rocks of the eastern microcontinent) probably was 

emplaced upon the Greenwich slice, which had become

part of a massive wedge of basement, miogeoclinal, 

and eugeoclinal rocks.

Following the aborted subduction of the continental margin in late Blackriveran time, southeast-dipping 

subduction may have started to the southeast of the 

microcontinent. The continued southeast-dipping subduction probably contributed to the thrust emplacement of the Richmond slice and to further telescoping 

of the North American continental margin. The amount 

of time required to close the marginal basin that 

separated the North American Continent from the 

microcontinent as determined by the age of the trench 

sediments of the Windsor Township Formation is 

approximately two graptolite zones, an amount of 

time equal to that suggested by Chappie (1973) for a 

similar model for the northern Appalachians.

Continued convergence drove the wedge of accreted 

rocks up the basal slope that had been created by 

subduction of the North American Continent. Elliot 

(1976) and Wiltscko (1979) maintain that thrust sheets 

can move up basal slope as long as sufficient surface 

slope has developed within the thrust sheet itself. The 

mass will move in the downdip direction of the surface 

slope even if this means moving up basal slope. Once 

the wedge of basement, miogeoclinal, and eugeoclinal 

rocks built up sufficient surface slope, probably by 

shortening in the back of the wedge, it was able to 

move up the basal slope.

The massive wedge of thickened continental crust 

and rocks of the Hamburg klippe continued to move 

throughout late Middle Ordovician time and caused 

further depression of the shelf. Rocks of the Martinsburg Formation were deposited in a clastic wedge in a 

foredeep in front of the wedge of accreted rocks (fig. 

34Z), E). The entire Martinsburg appears to have been 

involved in nappe formation to some extent, which 

suggests that the nappes continued to "form" into 

Maysvillian time (see fig. 34F). The nappes continued 

to develop by movement along thrust faults separating 

each of the basement-cored nappes.

The Hamburg klippe may have become detached 

from the underlying nappes and may have slid in 

advance of them into the Martinsburg basin (fig. 34#). 

The mixed allochthonous-autochthonous terrane in 

the vicinity of Harrisburg, Pa., attests to the subaqueous gravity sliding mechanism for the emplacement of 

the Hamburg klippe into the Martinsburg basin. The 

age of the final emplacement of the klippe is not known. 

The matrix of the wildflysch at the western end of the 

klippe has not been dated, and there is no wildflysch at 

the eastern end despite previous reports (Alterman, 

1972). If there were wildflysch at the eastern end, it 

has been removed by faulting or is not exposed at the
PLATE TECTONIC IMPLICATIONS 35

present level of erosion.

Wright and Stevens (1978) suggest that the allochthons were emplaced during the lower Diplograptus 

multidens graptolite zone. This emplacement seems 

impossible if the minimum age of the Jacksonburg 

Limestone is early Rocklandian. Emplacement of the 

allochthons into the Martinsburg basin during lower 

Diplograptus multidens time would require uplift of 

the continental margin, detachment of basement and 

resultant nappe formation, and deposition of the Jacksonburg Limestone and a certain thickness of rocks of 

the Martinsburg Formation within a very short time. 

A more likely time of emplacement by analogy with 

the emplacement of the Normanskill Formation of 

New York State (Rickard and Fisher, 1973) and the 

Taconic klippe of New England (Zen, 1967) is the 0. 

Reudemanni graptolite zone or late Sherman Falls, 

although direct evidence is lacking. The true age of the 

final emplacement of the Hamburg klippe will not be 

known until datable fossils are obtained from wildflysch associated with the allochthons.

Finally, as motion of the two plates slowed and 

eventually stopped, post-Maysvillian slow heating and 

uplift resulted in the unconformity separating the 

Taconides of the Great Valley and the Alleghanides of 

the Valley and Ridge (Drake, 1980). Late Alleghanian 

thrusting, such as that described by Root (1977) and 

Root and MacLachlan (1978), from the western end of 

the klippe and the Kutztown thrust of the eastern end 

continues to move the nappes of the Reading Prong 

nappe megasystem to the northwest over the klippe 

rocks.

A modern analogy of the proposed model exists in 

the vicinity of Timor Island north of Australia. Timor 

Island, located in the outer Banda Arc (Hamilton, 1977, 

1979; Von der Borch, 1979), consists of a chaotic complex of highly deformed and imbricated rocks and was 

interpreted to be a tectonic melange by Fitch and 

Hamilton (1974) and Hamilton (1979). Seismic profiles 

of the island indicate a wedge-shaped morphology 

(Von der Borch, 1979) that thins to the south. Deep-sea 

drilling in the Timor Trough (Hamilton, 1977) south of 

Timor shows that shallow-water carbonate rocks of the 

Australian shelf underlie the trench fill and indicates 

foundering of the shelf. Foundering of the Australian 

shelf and attendant block faulting has been attributed 

to subduction of the continental margin beneath the 

Banda Arc (Crostella, 1977; Hamilton, 1979). The 

chaotic rocks of Timor Island, therefore, are considered to be part of an accretionary prism of trench, 

shelf, and crystalline rocks that moved with the upper 

plate (Hamilton, 1979) during subduction of the Australian shelf and basement.

Although obvious differences exist, the proposal 

model and the present-day tectonics of the TimorTanimbar area are grossly similar. The melange rocks 

of the Greenwich slice are similar in style of deformation and stratigraphy to the melange on Timor Island. 

In addition, the crystalline cores of the nappes of the 

Reading Prong nappe megasystem are represented on 

Timor Island by slabs of what appear to be Australian 

basement. Future research on the rocks of the Great 

Valley will undoubtedly clarify certain points of the 

proposed model and help to refine our ideas of the 

early Paleozoic plate tectonics of the central Appalachians.

CONCLUSIONS

Taconic-type klippen such as the well-known examples from the northern and maritime Appalachians 

also have been described from the central Appalachians. The Hamburg klippe of Stose (1946) constitutes one such body in the Great Valley of eastern 

Pennsylvania. The eastern end of the allochthon was 

mapped in the Kutztown and Hamburg 7%-minute 

quadrangles and surrounding areas.

This mapping has led to the recognition of two 

stratigraphically and structurally different slices. 

The lower Greenwich slice consists of rocks of the 

Windsor Township Formation (6,215 m), a flysch sequence that contains various sized bodies of chert, 

limestone, and variegated shale and boulder conglomerate. The rocks of the Windsor Township are subdivided into three members: (1) the Dreibelbis, a sequence of interbedded graywacke and gray-green 

shale, siltstone, and mudstone, (2) the Weisenberg, a 

gray-green shale unit that contains local lenses of polymict conglomerate, and (3) the Switzer Creek, a conglomeratic graywacke-gray-green-shale unit. The 

lenticular bodies of chert, limestone, and variegated 

shale and mudstone are not restricted to a particular 

member but occur throughout the formation and, 

therefore, have little regional stratigraphic significance. Graptolites collected from the flysch sequence 

of the Windsor Township yield Middle Ordovician 

(Nemagraptus gracilis zone) ages, whereas conodonts 

from the carbonate rocks of the bodies of red shale and 

associated rocks yield Early Ordovician (Arenigian) 

ages. Therefore, a definite age discrepancy exists 

between the two types of rock within the Windsor 

Township Formation.

Sedimentologic analysis of the flyschoid rocks of 

the Windsor Township Formation suggests that the 

rocks can be classified into one of four turbidite facies 

described by Mutti (1977) in his study of a flysch
36 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

sequence from the Spanish Pyrenees. These are (1) the 

channel-margin facies characterized by thick, massive 

(Ta, Ta_e partial Bouma sequences) graywacke beds 

locally interbedded with the Tc_e partial Bouma sequence and very thick intervals of siltstone and mudstone, (2) the channel-axis facies characterized by 

monotonous sequences of thick, massive (Ta , Ta e ) 

graywacke sandstone, (3) the interchannel facies 

characterized by sequences of bundles of Tc _e partial 

Bouma sequences intercalated with mudstone and 

siltstone, and (4) levee and overbank deposits characterized by mudstone and shale, locally slumped. The 

Dreibelbis Member contains rocks of the channelmargin, channel-axis, and interchannel facies, whereas most rocks of the Switzer Creek Member appear to 

be typical of the channel-axis facies. The Weisenberg 

Member appears to be a good example of levee and 

overbank mudstone and siltstone deposits. These rocks 

were probably deposited in the middle-fan area of a 

large submarine fan from a source to the southeast. 

The activity of the channels in the fan is evidenced by 

the intercalated nature of channel-axis and interchannel facies rocks. This sediment mixing suggests 

that the channels were meandering freely rather than 

being incised into the fan mud as would be expected in 

the upper parts of the fan. The older lenticular bodies 

of chert, deepwater limestone, and variegated shale 

were apparently deposited in an abyssal environment 

that received periodic influxes of terrigenous material. 

They were later emplaced into the younger fan deposits.

The upper Richmond slice contains rocks of the 

Virginville Formation (565 m thick) and is divided 

into three members. (1) The Sacony (245 m thick) consists of olive-green siltstone and shale. (2) The Onyx 

Cave (90 m thick) consists of massive to laminated 

calcarenite, ribbon limestone, massive carbonate-clast 

conglomerate, and interlaminated black shale and 

orange dolostone. (3) The Moselem (230 m thick) consists of well-cleaved argillite and mudstone and lesser 

proportions of ribbon limestone and carbonate-clast 

conglomerate. The limited amount of faunal evidence 

from these rocks suggests a Late Cambrian to Early 

Ordovician age. The sedimentology and stratigraphy 

of these rocks suggest that (1) they were deposited low 

on a northwest-facing depositional slope and (2) the 

Moselem Member is a distal equivalent of the Onyx 

Cave Member. The data suggest that the rocks of the 

Virginville were deposited on a northwest-dipping 

depositional slope, probably adjacent to a shallowwater carbonate shelf to the southeast. Subsequent 

thrusting juxtaposed the Sacony and Onyx Cave on top 

of the Moselem.

The rocks of the Hamburg klippe have been 

deformed by three phases of folding. In addition, the

Greenwich slice illustrates the effects of an earlier 

phase of deformation not present in the rocks of the 

Richmond slice. The rocks of the Greenwich slice 

exhibit a chaotic style of deformation characterized by 

pinch-and-swell and pull-apart structures. These rocks 

lack the well-developed slaty cleavage typical of lithologically similar rocks in the surrounding parautochthonous Lehigh Valley sequence.

First-phase deformation is typified by eastnortheast-eastsoutheast-trending folds. A slaty cleavage is 

axially planar to these folds in the Lehigh Valley 

sequence and in the incompetent rocks of the Richmond 

slice, but slaty cleavage is almost totally absent from 

rocks of the Greenwich slice. Second-phase deformation is characterized by northeast-trending strain-slip 

and fracture cleavage and minor folds and is well 

displayed in all rocks of the allochthon. Finally, thirdphase deformation is not well developed, but the structures that appear to be related to this deformation 

trend eastnortheast. This deformation can be distinguished from the first phase only where cross-cutting 

relations exist.

A conceptual plate tectonic model for the lower 

Paleozoic section of the central Appalachians has been 

developed. The model synthesizes structural, sedimentologic, and stratigraphic data of the present 

study with interpretations and conclusions of other 

geologists who have worked in the central Appalachian 

Great Valley. The proposed model explains the distribution of the allochthonous and parautochthonous 

rocks in the Great Valley in terms of the present-day 

tectonics of the Banda Sea north of Australia.

Late Proterozoic rifting resulted in the formation 

of a basin separating the North American craton and a 

microcontinent to the southeast. The microcontinent 

may be represented by such basement complexes as 

the Fordham Gneiss and Baltimore Gneiss terranes. 

From Early Cambrian to Early Ordovician time, a 

stable carbonate platform was established on the 

North American craton as evidenced by the Frederick 

Valley sequence of Maryland and the parautochthonous 

carbonate rocks of the Pennsylvania Great Valley. 

Formation of a carbonate platform on the microcontinent is illustrated by the Setters Formation and Cockeyville Marble overlying basement rocks of the Baltimore Gneiss (Thomas, 1977). The Virginville Formation, therefore, may represent Upper Cambrian to 

Lower Ordovician slope and lower slope rocks that 

were deposited basinward of a carbonate shelf on the 

microcontinent. Deposition of the deepwater olistoliths 

of chert, limestone, and variegated shale and mudstone 

of the Windsor Township Formation occurred concomitant with E arly Ordovician shelf deposition of the 

Beekmantown Group.
CONCLUSIONS 37

Subduction of the North American Continent probably began in early Early Ordovician time. Chazyan 

foundering of the shelf in response to subduction 

resulted in transgression characterized by deposition 

of high-calcium limestone such as the Annville Limestone. The trench sediments of the Windsor Township 

Formation were deposited in the middle-fan area of a 

large submarine fan. A southeasterly source for these 

sediments suggests that the fan was adjacent to the 

microcontinent. Trench sedimentation and melange 

deformation evidenced by the rocks of the Greenwich 

slice occurred during Chazyan time and was coeval 

with foundering of the North American shelf. As subduction continued, the chert, limestone, and variegated 

shale and mudstone units were detached from the 

subducting plate by the process of selective subduction 

and incorporated into the progressively deforming 

trench sediments.

As the North American Continent approached the 

trench, the continental margin was uplifted as a result 

of the aborted subduction of the buoyant continental 

material, and the plates became locked. Erosion of the 

shelf sediments in response to uplift produced the 

Black River hiatus. Deposition of the Jacksonburg 

Limestone to the northwest of the tectonic welt indicates that uplift and erosion were in progress by Rocklandian time. Continued uplift resulted in the transition from the shallow-water "cement limestone" facies 

to the deeper water "cement rock" facies.

The inability of the North American craton to be 

subducted beneath the microcontinent resulted in late 

Blackriveran to Kirkfieldian underthrusting and detachment of slabs of cratonic basement on easterly 

inclined faults. These slabs of basement and associated 

miogeoclinal rocks are represented by the carbonate 

nappes in the Lehigh and Lebanon Valleys. Continued 

convergence from the southeast, possibly as a result of 

a shift from southeast-dipping to northwest-dipping 

subduction southeast of the microcontinent, resulted 

in the thrust emplacement of the Richmond slice onto 

the Greenwich slice by Edenian time.

Sediments of the Martinsburg Formation were 

shed from the northwestward-advancing wedge of 

basement, miogeoclinal, and eugeoclinal rocks in a 

foredeep. As the wedge continued to move, the allochthons became detached from the underlying carbonate 

nappes and slid into the Martinsburg basin in advance 

of the nappes. This may have occurred in late Shermanian time although direct evidence is lacking. 

Nappe formation continued into Maysvillian time by 

thrusting along faults separating each of the basementcored carbonate nappes.

As motion between the two plates ceased, heating 

and uplift occurred in Maysvillian and Richmondian

time and resulted in the post-Martinsburg deposition 

(Hudson Valley) unconformity. Later Alleghanian 

thrust faulting further telescoped the nappes (Drake, 

1978) and translated them over the rocks of the Hamburg klippe.

REFERENCES CITED

Alterman, I. B., 1972, Structure and history of the Taconic and surrounding autochthon, east-central Pennsylvania: Columbia University, unpub. Ph.D. dissertation, 287 p.

Bergstrom, S. M., Epstein, A. G., and Epsteiri, J. B., 1972, Early 

Ordovician North Atlantic Province conodonts in eastern Pennsylvania: U.S. Geological Survey Professional Paper 800-D, p. 

D37-D44.

Berkland, J. 0., Raymond, L. A., Kramer, J. C., Moores, E. M., and 

O'Day, Michael, 1972, What is Franciscan?: Am. Assoc. Petroleum Geologists, 56, p. 2295-2302.

Berry, W. B. N., 1960, Graptolite faunas of the Marathon region, 

Texas: Univ. Texas Pub. 6005, 179 p.

___1968, Ordovician paleogeography of New England and adjacent areas based on graptolites, in Zen, E-An, White, W. S., 

Hadley, J. B., and Thompson, J. B., Jr., eds., Studies of Appalachian Geology: Northern Maritime: New York, Wiley Interscience, p. 23-35.

Beutner, E.G., 1975, Tectonite and melange A distinction: Geology, 

3, p. 358.

Bird, J. M., 1969, Middle Ordovician gravity sliding Taconic region, in Kay, Marshall, ed.. North Atlantic geology and continental draft: Am. Assoc. Petroleum Geologists Mem. 12, p. 

670-686.

Bird, J. M., and Dewey, J. F., 1970, Lithosphere plate-continental 

margin tectonics and the evolution of the Appalachian orogen: 

Geol. Soc. America Bull., 81, p. 1031-1060.

Bouma, A. H., 1962, Sedimentology of some flysch deposits, a graphic 

approach to facies interpretations: Amsterdam, Elsevier Publishing Co., 168 p.

___1972a, Recent and ancient turbidites and contourites: Gulf 

Coast Assoc. Geol. Soc. Trans., 22, p. 205-221.

___1972b, Fossil contourites in lower Neisenflysch, Switzerland:

Jour. Sed. Petrology, 42, p. 917-921.

Bouma, A. H., and Hollister, C. D., 1973, Deep ocean basin sedimentation: Soc. Econ. Paleontologists and Mineralogists. Pacific Sec. 

Short Course, Anaheim, Calif., 157 p.

Chappie, W. M., 1973, Taconic orogeny: abortive subduction of the 

North American continental plate: Geol. Soc. America Abs. 

with Programs, 5, p. 573.

Cook, H. E., 1979, Ancient continental slope sequences and their 

value in understanding modern slope development, in Doyle, L. 

J., and Pilkey, 0. H., eds., Geology of continental slopes: Soc. 

Econ. Paleontologists and Mineralogists Spec. Pub. 27, p. 

287-305.

Cook, H. E., McDaniel, P. N., Mountjoy. E. W., and Pray, L. C., 1972, 

Allochthonous carbonate debris flows at Devonian ("reef") 

margins, Alberta, Canada: Bull., Canadian Petroleum Geol., 

20, p. 439-497.

Cook, H. E., and Taylor, M. E., 1977, Comparison of continental slope 

and shelf environments in the upper Cambrian and lowest 

Ordovician of Nevada, in Cook, H. E., and Enos, Paul, eds., 

Deep-water carbonate environments: Soc. of Econ. Paleontologists and Mineralogists Spec. Pub. 25, p. 51-81.

Corbett, K. D., 1973, Open-cast slump sheets and their relationship 

to sandstone beds in an Upper Cambrian flysch sequence, Tas-
38 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

mania: Jour. Sed. Petrology, v. 43, p. 147-159.

Cowan, D. S., 1974, Deformation and metamorphismof the Franciscan subduction zone complex northwest of Pacheco Pass, California: Geol. Soc. America Bull., 85, p. 1623-1634.

Crook, K. A. W., 1960, Classification of arenites: Am. Jour. Sci., 258,

p.419-428.

 1974, Lithologenesis and geotectonics: The significance of 

compositional variation in flysch arenites (graywackes), in 

Dott, R. H., Jr., and Shaver, R. H., eds., Modern and ancient 

geosynclinal sedimentation: Soc. Econ. Paleontologists and 

Mineralogists Spec. Pub. 19, p. 304-309.

Crostella, A., 1977, Geosynclines and plate tectonics in Banda arcs, 

eastern Indonesia: Am. Assoc. Petroleum Geologists, 61, p. 

2062-2081.

Dickinson, W. R., 1970, Interpreting detrital modes of graywacke 

and arkose: Jour. Sed. Petrology, 40, p. 695-707.

___1971, Detrital modes of New Zealand graywackes: Sed. Geology, 5, p. 37-56. 

-1982, Compositions of sandstones in circum-Pacific subduction complexes and fore-arc basins: AAPG Bull., v. 66, no. 2, p. 

121-137.

Drake, A. A., Jr., 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 excursions: New Brunswick, N.J., Rutgers University Press, p. 57-131.

___1978, The Lyon Station-Paulins Kill nappe The frontal structure of the Musconetcong nappe system in eastern Pennsylvania 

and New Jersey: U.S. Geological Survey Professional Paper 

1023, 20 p.

___1980, The Taconides, Acadides, and Alleghenides in the

central Appalachians, in Wones, D. R., ed.. Proceedings, The 

Caledonides in the USA, IGCP Project 27 Caledonie orogen, 

1979 Meeting, Blacksburg, Va.: Virginia Polytechnic Institute 

and State University Memoir 2, p. 179-187.

Elliott, David, 1976, The motion of thrust sheets: Jour. Geophys. 

Research v. 81, p. 949-963.

Elsasser, W. M., 1971, Sea-floor spreading as thermal convection: 

Jour. Geophysical Research, v. 76, no. 5, p. 1101-1112.

Elter, P., and Trevisan, L., 1973, Olistostromes in thetectonic evolution of the northern Appenines, in Dejong, K. A., and Sholten, 

Robert, eds., Gravity and tectonics: John Wiley, New York, p. 

343-360.

Epstein, J. B., and Berry, W. B. N., 1973, Graptolites from the Martinsburg Formation, Lehigh Gap, eastern Pennsylvania: U.S. 

Geological Survey Journal of Research, 1, p. 33-37.

Epstein, J. B., Epstein, A. G., and Bergstrom, S. M., 1972, Significance of lower Ordovician exotic blocks in the Hamburg klippe, 

eastern Pennsylvania: U.S. Geological Survey Professional 

Paper 800-D, p. D29-D36.

Fitch, T. J., and Hamilton, Warren, 1974, Plate convergence, transcurrent faults, and internal deformation adjacent to southeast 

Asia and the western Pacific Reply: Jour. Geophys. Research, 

v. 79, p. 4982-4985.

Glover, Lynn, III, and Sinha, A. K., 1973, The Virgilina deformation, 

a Late Precambrian to Early Cambrian(?) orogenic event in the 

central Piedmont of Virginia and North Carolina: Am. Jour. 

Sci., 273-A, p. 234-251.

Goddard, E. N., and others, 1948, Rock-color chart, Washington, 

D.C., National Research Council [repub. by Geol. Soc. America, 

1951], 6 p.

Graham, S. A., Dickinson, W. R., and Ingersoll, R. V., 1975, Himalayan-Bengal model for flysch dispersal in the AppalachianOuachita system: Geol. Soc. America, 86, p. 273-286.

Gray, Carlyle, Sheps, V. C., and others, 1960, Geologic map of Pennsylvania: Pa. Geol. Survey, 4th ser., Map 1, scale 1:250,000.

Gray, Carlyle, and Willard, Bradford, 1955, Stratigraphy and structure of lower Paleozoic rocks in eastern Pennsylvania, in Field 

guidebook of Appalachian geology, Pittsburg to New York: 

Pittsburg, Geol. Soc., p. 87-92.

Hall, B. A., 1973, Slump folds and the determination of paleoslope 

[abs.]: Geol. Soc. America Abs. with Programs, v. 5, p. 648.

Hamilton, Warren, 1977, Subduction in the Indonesian region, in 

Talwani, Manik, and Pittman, W. C., Ill, eds., Island arcs, 

deep-sea trenches, and back-arc basins; Am. Geophys. Union. 

Washington, D.C., Maurice Ewing Series 1, p. 15-31.

___1979, Tectonics of the Indonesian region: U.S. Geological 

Survey Professional Paper 1078, 345 p.

Hampton, M. A., 1972, The role of subaqueous debris flow in generating turbidity currents: Jour. Sed. Petrology, 42, p. 775-793.

Hansen, Edward, 1967, Methods of deducing slip-line orientations 

from the geometry of folds: Carnegie Inst. Wash. Year Book 65, 

p.387-405.

___1971, Strain facies: Springer-Verlag, New York, 207 p.

Hatcher, R. D., Jr., 1978, Synthesis of the southern and central 

Appalachians, USA, in IGCP Project 27, Caledonian-Appalachian orogen of the North Atlantic region: Geological Survey 

of Canada, Paper 78-13, p. 149-157.

Heezen, B. C., and Hollister, C. D., 1964, Deep-sea current evidence 

from abyssal sediments: Marine Geology, 1, p. 141-174.

Hiscott, R. N., 1978, Provenance of Ordovician deep-water sandstones of the Tourelle Formation, Quebec, and implications for 

initiation of the Taconic orogeny: Canadian Jour. Earth Sci., 15, 

p. 1579-1597.

Hubert, J. F., Suchecki, R. K., and Callahan, R. K., 1977, The Cow 

Head Breccia: Sedimentology of the Cambro-Ordovician continental margin, Newfoundland, in Cook, H. E., and Enos, Paul, 

eds., Deep-water carbonates: Soc. Econ. Paleontologists and 

Mineralogists Spec. Pub. 25, p. 125-154.

Ingersoll, R. V., 1978, Submarine fan facies of the upper Cretaceous 

Great Valley sequence, northern and central California: Sed. 

Geology, 21, p. 205-230.

Johnson, A. M., 1970, Physical processes in geology: San Francisco, 

Freeman, Cooper, and Co., 577 p.

Jonas, A. L, and Stose, G. W., 1938, Geologic map of Frederick 

County: Maryland Geologic Survey, 1:62,500.

Kay, G. M., 1941, Taconic allochthon and the Martic thrust: Science, 

94, p. 73.

Keith, B. D., and Friedman, G. M., 1977, A slope-fan-basin model, 

Taconic sequence, New York and Vermont: Jour. Sed. Petrology, 47, p. 1220-1241.

Kodama, K. P., and Lash, G. G., 1980, Preliminary paleomagnetic 

results from late Early Ordovician red shale units in Taconic 

allochthons, eastern Pennsylvania [abs.]: EOS, v. 61, p. 220

Krause, F. F., and Oldershaw, A. E., 1979, Submarine carbonate 

breccia beds A depositional model for two-layer, sediment 

gravity flows from the Sekwi Formation (lower Cambrian), 

MacKenzie Mountains, Northwest Territories, Canada: Canadian Jour. Earth Sci., 16 p. 189-199.

Lash, G. G., 1980a, the Hamburg klippe Evidence for a continental icrocontinent collision in the central Appalachians [abs.]: 

Geol. Soc. America Abs. with Programs, v. 12, p. 68.

___1980b, Structural geology and stratigraphy of the allochthonous and authochthonous rocks of the Kutztown and 71/4-minute 

quadrangles, eastern Pennsylvania: unpublished Ph.D. dissertation, Lehigh University, Bethlehem, Pa., 266 p.

___Geologic map of the Kutztown quadrangle, Pennsylvania: 

U.S. Geological Survey Geologic Quadrangle Map, scale
REFERENCES CITED 39

1:24,000, [in press].

Lewis, K. B., 1971, Slumping on a continental slope inclined at l°-4°: 

Sedimentology, 16, p. 97-110.

Lyttle, P. T., and Drake, A. A., Jr., 1979, Discussion: Regional implications of the stratigraphy and structure of Shochary Ridge, 

Berks and Lehigh Counties, Pennsylvania: Am. Jour. Sci., 279, 

p.721-728.

MacLachlan, D. B., 1967, Structure and stratigraphy of the limestones and dolomites of Dauphin County, Pennsylvania: Pennsylvania Geologial Survey, 4th ser., Gen. Geol. Rpt. 44, 168 p.

___1979, Geology of the Temple and Fleetwood quadrangles: 

Pennsylvania Geological Survey, 4th ser., Atlas 187ab, 71 p.

MacLachlan, D. B., Buckwalter, T. V., and McLaughlin, D. B., 1975, 

Geology and mineral resources of the Sinking Spring quadrangle: Pennsylvania Geological Survey, 4th ser.. Atlas 177d, 228 p.

McBride, E. F., 1962, Flysch and associated sediments of the Martinsburg Formation (Ordovician), central Appalachians: Jour. 

Sed. Petrology, 32, p. 39-91.

McBridge, D. E. 1976, Tectonic setting of the Tetagouche Group, 

host to the New Brunswick polymetallic massive sulphide deposits, in Strong, D. F., ed., Metallogeny and plate tectonics: 

Geol. Assoc. Canada Spec. Paper 14, p. 473-485.

Mcllreath, I. A., and James, N. P., 1978, Facies model 13: Carbonate 

slopes: Geoscience Canada, 5, p. 189-199.

McKee, E. D., and Weir, G. W., 1953, Terminology for stratification 

and cross-stratification in sedimentary rocks: Geol. Soc. America Bull., v. 64, p. 381-389.

Miller, R. L., 1937, Martinsburg limestones in eastern Pennsylvania: 

Geol. Soc. America Bull., 48, p. 93-112.

Mitchell, A. H. G., and Reading, H. G., 1969, Continental margins, 

geosynclines, and ocean floor spreading: Jour. Geology, v. 77, p. 

629-646.

Moore, J. C., 1975, Selective subduction: Geology, 3, p. 530-532.

Moore, J. C., and Geigle, J. F., 1972, Incipient axial plane cleavage: 

Deep sea occurrence: Geol. Soc. America Abs. with Programs, 

4, p. 600.

Moore, J. C., and Wheeler, R. L., 1978, Structural fabric of a melange, 

Kodiak Islands, Alaska: Am. Jour. Sci., v. 278, p. 739-765.

Mutti, Emiliano, 1977, Distinctive thin-bedded turbidite facies and 

related depositional environments in the Eocene Hecho Group 

(south-central Pyrenees, Spain): Sedimentology, 24, p. 107-131.

Mutti, Emiliano, and Ricci-Lucchi, F., 1978, Turbidites of the northern Appennines: Introduction to facies analysis: Internal. Geology Rev., 20, p. 125-166.

Myers, P. B., Jr., 1969, Development of the Hamburg klippe in the 

Bernville-Strausstown area, Pennsylvania [abs.]: Geol. Soc. 

America Abs. with Programs, 1, p. 55-56.

Nelson, C. H., Mutti, Emiliano, and Ricci-Lucchi, Franco, 1974, Criteria for distinguishing thin-bedded turbidites deposited in 

proximal overbank and distal basin plain environments [abs.]: 

Geol. Soc. America Abs. with Programs 6, p. 887-888.

Nelson, C. H., and Nilsen, T. H., 1974, Depositional trends of modern 

and ancient deep-sea fans, in Dott, R. H., Jr., and Shaver, R. H., 

eds.. Modern and ancient geosynclinal sedimentation: Soc. 

Econ. Paleontologists and Mineralogists Spec. Pub. 19, p. 

69-91.

Normark, W. R., 1970, Growth patterns of deep-sea fans: AAPG

Bull., v. 54, p. 2170-2195.

Osberg, P. H., 1978, Synthesis of the geology of the northeastern 

Appalachians, USA, in IGCP Project 27, Caledonian-Appalachian Orogen of the North Atlantic region: Geological Survey 

of Canada, Paper 78-13, p. 137-147.

Perissoratis, Constantine, Brock, P. W. G., Bruckner, H. K., Drake, 

A. A., Jr., and Berry, W. B. N., 1979, The Taconides of western

New Jersey: New evidence from the Jutland klippe: Geol. Soc. 

America Bull., 90, Pt. II, p. 154-177.

Platt, L. B., Loring, R. B., Papaspyros, Athanasios, and Stephens, G. 

C., 1972, The Hamburg klippe reconsidered: Am. Jour. Sci., 

272, p. 305-318.

Rankin, D. W., 1975, The continental margin of eastern North 

America in the southern Appalachians: The opening and closing of the proto-Atlantic ocean: Am. Jour. Sci., 275-A, p. 

398-436.

Ratcliffe, N. M., 1979, Basement-cover rock interactions during remobilization of the Greenvillian core of the Green Mountains 

Berkshire Massive in the Taconic orogeny [abs.]: Abstracts of 

the IGCP project: The Caledonides in the USA, Blacksburg, 

Va., p. A15.

Raymond, L. A., 1975a, Tectonite and melange: A distinction: Geology, 3, p. 7-9. 

1975b, Reply to tectonite and melange: Geology, 3, p. 358-359.

Reinhardt, Juergen, 1974, Stratigraphy, Sedimentology, and Cambro-Ordovician paleogeography of the Frederick Valley, Maryland: Maryland Geological Survey, Report of Investigations 23, 

74 p. 

.1977, Cambrian off-shelf sedimentation, central Appalachians, in Cook H. E., and Enos, Paul, eds., Deep-water carbonates: Soc. Econ. Paleontologists and Mineralogists Spec. Pub., 

25, p. 83-112.

Rickard, L. V., and Fisher, D. W., 1973, Middle Ordovician Normanskill Formation, eastern New York, age, stratigraphic, and 

structural position: Amer. Jour. Sci., 273, p. 580-590.

Rodgers, John, 1968, The eastern edge of the North American Continent during the Cambrian and Early Ordovician, in Zen, E-An, 

White, W. S., Hadley, J. B., and Thompson, J. B., Jr., eds., Studies 

of Appalachian Geology, northern and maritime: Interscience, 

New York, p. 141-149.

Root, S. I., 1977, Geology and mineral resources of the Harrisbuirg 

West area: Pennsylvania Geological Survey, 4th ser., Atlas 

148ab,106 p.

Root, S. I., and MacLachlan, D. B., 1978, Western limit of Taconic 

allochthons in Pennsylvania: Geol. Soc. America Bull., 89, p. 

1515-1528.

St. Julien, P., and Hubert, C., 1975, E volution of the Taconic orogen 

in the Quebec Appalachians: Amer. Jour. Sci., 275-A, p. 

337-362.

Schenk, P. E., 1978, Synthesis of the geology of the Canadian Appalachians, in IGCP Project 27, Caledonian-Appalachian orogen 

of the North Atlantic region. Geological Survey of Canada 

Paper 78-13, p. 111-136.

Scholle, P. A., 1978, Deposition, diagenesis, and hydrocarbon potential of "deeper-water" limestones: Am. Assoc. Petroleum Geologists Continuing Education Course Notes, ser. no. 7, 25 p.

Schwab, F. L., 1975, Framework mineralogy and chemical composition of continental margin-type sandstone: Geology, 3, p. 

487-490.

Shanmugam, Ganapathy, and Benedict, G. L. Ill, 1978, Fine-grained 

carbonate debris flow, Ordovician basin margin, southern 

Appalachians: Jour. Sed. Pet., v. 48, no. 4, p. 1233-1239.

Shanmugam, Ganapathy, and Walker, K. R., 1978, Tectonic significance of distal turbidites in the Middle Ordovician Blockhouse 

and lower Sevier Formations in east Tennessee: Am. Jour. Sci., 

v. 278, p. 551-578.

Shepard, F. P., 1966, Meander in valley crossing a deep-ocean fan: 

Science, 154, p. 347-356.

Stanley, Rolfe, and Ratcliffe, N. M., 1979, Thrust faults in the HoosacRowe sequence of Massachusetts and their bearing on the 

reconstruction of the Caledonides in western New England
40 RICHMOND AND GREENWICH SLICES OF THE HAMBURG KLIPPE IN EASTERN PENNSYLVANIA

[abs.]: Abstracts of the IGCP project: The Caledonides in the

USA, Blackburg, Va.. p. A6. 

Stevens, R. K., 1970, Cambro-Ordovician flysch sedimentation and

tectonics in west Newfoundland and their possible bearing on a

proto-Atlantic ocean: Geol. Assoc. Canada Spec. Paper 7, p.

165-177. 

Stewart, R. J., 1976, Turbidites of the Aleutian abyssal plain;

mineralogy, provenance, and constraints for Cenozoic motion of

the Pacific plate: Geol. Soc. America Bull., v. 87, no. 5, p. 793-808. 

Stone, B. D., 1976, Analysis of slump slip lines and deformation

fabric in slumped Pleistocene lake beds: Jour. Sed. Petrology,

46, p. 313-325. 

Stose, G. W., 1946, The Taconic sequence in Pennsylvania: Am. Jour.

Sci., 244, p. 665-696. 

___1950a, Evidence of the Taconic sequence in the vicinity of

Lehigh River, Pennsylvania: Am. Jour. Sci., 248, p. 815-819. 

-1950b, Comments on the Taconic sequence in Pennsylvania:

Geol. Soc. America Bull., 61, p. 133-135.

Stose, G. W., and Jonas, A. T., 1927, Ordovician shale and associated 

lava in southeastern Pennsylvania: Geol. Soc. America Bull., 38, 

p.505-536.

Stow, D. A. V., and Shanmugam, Ganapathy, 1980, Sequence of 

structures in fine-grained turbidites, comparison of recent 

deep-sea and ancient flysch sediments: Sedimentary Geol., v. 

25, no. 1-2, p. 23-42.

Suttner, L. J., 1974, Sedimentary petrographic provinces: An evaluation, in Ross, C. A., ed., Paleogeographic provinces and provinciality: Soc. Econ. Paleontologists and Mineralogists, spec. 

Pub. 21, p. 75-84.

Thomas, W. A., 1977, Evolution of Appalachian-Ouachita salients 

and recesses from reentrants and promontories in the continental margin: Am. Jour. Sci., 277, p. 1233-1278.

Von der Borch, C. C., 1979, Continent-island arc collision in the 

Banda Arc: Tectonophysics, 54, p. 169-193.

Walker, R. G., 1970, Review of the geometry and facies organization 

of turbidites and turbidite-bearing basins, in Lajoie, J., ed., 

Flysch sedimentology in North America: Geol. Assoc. Canada 

Spec. Paper 7, p. 219-251.

Walker, R. G., 1975, Generalized facies model for resedimented conglomerates of turbidite association: Geol. Soc. America Bull., 

86, p. 737-748.

Wheeler, R. L., 1978, Slip planes from Devonian Millboro Shale, 

Appalachian Plateau province: Statistical extentions of discfold analysis: Am. Jour. Sci., v. 278, p. 497-517.

Whitcomb, L. and Engel, J. A., 1934, The probable Triassic age of 

the Spitzenberg conglomerate, Berks County, Pa.: Pennsylvania Acad. Sci. Proc., v. 8, p. 37-43.

Willard, Bradford, 1939, Ordovician shale of southeastern Pennsylvania: Pennsylvania Acad. Sci. Proc., 13, p. 126-133.

_____1943, Ordovician clastic sedimentary rocks in Pennsylvania: 

Geol. Soc. America Bull., 54, p. 1067-1122.

Williams, Harold, 1975, Structural succession, nomenclature, and 

interpretation of transported rocks in western Newfoundland: 

Canadian Journal Earth Sci., 12, p. 1874-1894.

Wilson, J. L., 1969, Microfacies in sedimentary structures in 

"deeper water" lime mudstone, in Friedman, G. M., ed., Depositional environments in carbonate rocks: Soc. Econ. Paleontologists and Mineralogists Spec. Pub. 14, p. 4-19.

Wiltschko, D. V., 1979, Partitioning of energy in a thrust sheet and 

implications concerning driving forces: Jour. Geophys. Research, 84, p. 6050-6058.

Wood, C. R., and MacLachlan, D. B., 1978, Ground-water resources 

of northern Berks County, Pennsylvania: Pennsylvania Geological Survey, 4th ser., Water Resources Map 44, 91 p.

Wright, T. 0., and Stephens, G. 0., 1978, Regional implications of 

the stratigraphy and structure of Shochary Ridge, Berks and 

Lehigh Counties, Pennsylvania: Am. Jour. Sci., v. 278, p. 

1000-10017.

Wright, T. 0., Wright, E. K., and Stephens, G. C., 1978, The autochthonous Martinsburg Formation of eastern Pennsylvania 

New evidence for a revised stratigraphy: Geol. Soc. America 

Abs. with Programs, 10, p. 91.

Wright, T. 0., Stephens, G. C., and Wright, E. K., 1979, A revised 

stratigraphy of the Martinsburg Formation of eastern Pennsylvania and paleogeographic consequences: Am. Jour. Sci., 

279, p. 1176-1186.

Zen, E-an, 1967, Time and space relationships of the Taconic allochthon and authochthon: Geol. Soc. America Spec. Paper 97,107

P-

___1972, The Taconide zone and the Taconic orogeny in the western part of the northern Appalachian orogeny: Geol. Soc. America Spec. Paper 135, 72 p.

Zen, E-an, and Ratcliffe, N. M., 1966, A possible breccia in 

southwestern Massachusetts and adjoining areas, and its bearing on the existence of the Taconic allochthon: U.S. Geological 

Survey Professional Paper 550-D, p. D39-46.

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