Contributions to New jersey Geology 

A. The Lake Hopatcong Intrusive Suite (Middle Proterozoic) of the New Jersey 

Highlands 

B. The High Point Member (Upper Ordovician) of the Martinsburg Formation in 

Northern New Jersey and Southeastern New York 

C. The Mount Eve Granite (Middle Proterozoic) of Northern New jersey and 

Southeastern New York 

D. The Byram Intrusive Suite of the Reading Prong-Age and Tectonic Environment 

U.S. GEOLOGICAL SURVEY BULLETIN 1952 

Prepared in cooperation with the 

New Jersey Geological Survey 

J.so 
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Ave. 
Contributions to New Jersey Geology 

Edited by AVERY ALA DRAKE, jR. 

A. The Lake Hopatcong Intrusive Suite (Middle Proterozoic) of the New Jersey 

Highlands 

By AVERY AlA DRAKE, JR., and RICHARD A. VOLKERT 

B. The High Point Member (Upper Ordovician) of the Martinsburg Formation in 

Northern New Jersey and Southeastern New York 

By AVERY AlA DRAKE, JR. 

C. The Mount Eve Granite (Middle Proterozoic) of Northern New Jersey and 

Southeastern New York 

By AVERY AlA DRAKE, JR., JOHN N. ALEINIKOFF, and RICHARD A. VOLKERT 

D. The Byram Intrusive Suite of the Reading Prong-Age and Tectonic Environment 

By AVERY AlA DRAKE, JR., JOHN N. ALEINIKOFF, and RICHARD A. VOLKERT 

Prepared in cooperation with the 

New Jersey Geological Survey 

U.S. GEOLOGICAL SURVEY BULLETIN 1952 
U.S. DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, Jr., Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Any use of trade, product, or firm names in this publication is for descriptive purposes 

only and does not imply endorsement by the U.S. Government 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1991 

For sale by the 

Books and Open-File Reports Section 

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Library of Congress Cataloging in Publication Data 

Contributions to New Jersey geology I edited by Avery Ala Drake, Jr. 

p. em. - (U.S. Geological Survey bulletin ; 1952) 

Includes bibliographical references. 

Supt. of Docs. no.: I 19.3:1952 

1. Geology-New Jersey. 2. Geology-New York (State) I. Drake, Avery Ala, 

1927- . II. Series. 

QE75.B9 no. 1952 

[QE141] 

557.3 s-dc20 

[557 .49] 90-13924 

CIP 
CONTENTS 

(Letters indicate the chapter) 

(A) The Lake Hopatcong Intrusive Suite (Middle Proterozoic) of the 

New jersey Highlands, by Avery Ala Drake, Jr., and Richard A. Volkert 

(B) The High Point Member (Upper Ordovician) of the Martinsburg 

Formation in Northern New Jersey and Southeastern New York, by 

Avery Ala Drake, Jr. 

(C) The Mount Eve Granite (Middle Proterozoic) of Northern New Jersey 

and Southeastern New York, by Avery Ala Drake, Jr., john N. 

Aleinikoff, and Richard A. Volkert 

(D) The Byram Intrusive Suite of the Reading Prong-Age and Tectonic 

Environment, by Avery Ala Drake, Jr., john N. Aleinikoff, and 

Richard A. Volkert 

Contents Ill 

Chapter A 

The Lake Hopatcong Intrusive Suite 

(Middle Proterozoic) of the 

New jersey Highlands 

By AVERY ALA DRAKE, jR., U.S. Geological Survey, and 

RICHARD A. VOLKERT, New jersey Geological Survey 

Prepared in cooperation with the 

New jersey Geological Survey 

U.S. GEOLOGICAL SURVEY BULLETIN 1952 

CONTRIBUTIONS TO NEW JERSEY GEOLOGY 

CONTENTS 

Abstract Al 

Introduction Al 

Byram Intrusive Suite Al 

Lake Hopatcong Intrusive Suite A4 

Regional Relations A 7 

References Cited AS 

FIGURES 

Al, A2. Maps showing: 

Al. Distribution of rocks older than 1 billion years in Eastern North 

America A2 

A2. Distribution of Middle Proterozoic rocks of the Reading Prong in 

New Jersey and immediately adjacent New York A3 

A3. Normative feldspar plot of rocks of the Byram Intrusive Suite A4 

A4. Quartz-alkali feldspar-plagioclase plot of rocks of the Lake Hopatcong Intrusive Suite AS 

AS. Normative feldspar plot of rocks of the Lake Hopatcong Intrusive Suite AS 

A6, A 7. Plots comparing: 

A6. Bulk chemistry of the Lake Hopatcong and Byram Intrusive 

Suites A6 

A 7. Normative mineralogy of rocks of the Lake Hopatcong and 

Byram Intrusive Suites A6 

AS. Normative feldspar plot of hornblende granite and alaskite from the Adirondack massif A 7 

A9. AFM plot comparing rocks of the Byram Intrusive Suite with hornblende 

granite and alaskite from the Adirondack massif A7 

AlO. Normative feldspar plot of quartz syenites from the Adirondack massif AS 

TABLES 

Al. Chemical analyses and CIPW norms of rocks of the Byram Intrusive Suite A4 

A2. Chemical analyses and CIPW norms of rocks of the Lake Hopatcong Intrusive 

Suite AS 

A3. Fe-Mg ratios of some rocks of the Lake Hopatcong and Byram Intrusive 

Suites A7 

Contents Ill 

The Lake Hopatcong Intrusive Suite (Middle 

Proterozo1ic) of the New Jersey Highlands 

By Avery Ala Drake, Jr., and Richard A. Volkert 

Abstract 

Detailed geologic mapping of the entire New Jersey 

Highlands has shown that quartz-poor and granitic rocks 

characterized by clinopyroxene and either mesoperthite 

or microantiperthite occur throughout. These rocks are 

particularly abundant in the Lake Hopatcong area and are 

included in the Lake Hopatcong Intrusive Suite (new 

name). They occur in large sheets thought to have been 

emplaced during the Grenville orogeny (1.1 Ga). The Lake 

Hopatcong rocks have not been recognized either in 

Pennsylvania or in southeastern New York, but are similar 

to quartz syenites in the Adirondack massif of New York. 

INTRODUCTION 

The New Jersey Highlands is the middle segment of 

the Reading Prong, one of the major external massifs of 

Middle Proterozoic rocks in the Appalachian orogen of 

Eastern North America (fig. AI). These highlands are 

continuous with the Durham and Reading Hills to the west 

and the Hudson Highlands to the east, the other segments of 

the Reading Prong (Drake and others, 1988). The Middle 

Proterozoic rocks of the Reading Prong consist of intrusive 

rocks and attendant migmatites, quartzofeldspathic and 

calcareous metasedimentary rocks, sodium-rich rocks of 

probable volcanic origin, and hypersthene-bearing charnockitic rocks of problematic origin. The distribution of these 

rocks in the New Jersey Highlands is shown in figure A2. 

Traditionally, the bulk of the Middle Proterozoic 

rocks in the New Jersey Highlands were considered to be 

intrusive and were divided into Byram "granite gneiss" 

(feldspar, dominantly potassic feldspar), Losee "diorite 

gneiss" (feldspar, dominantly plagioclase), and Pochuck 

"gabbro gneiss" (mafic rocks). These units were thought to 

grade into each other through intermediate forms (Spencer 

and others, 1908; Bayley, 1941). Some metasedimentary 

units were recognized, however, including the Franklin 

Limestone (Spencer and others, 1908) and the Pickering 

Gneiss near the Delaware River (Bayley, 1941). Since the 

Manuscript approved for publication July 19, 1990. 

end of World War II, many detailed examinations have 

been made in New Jersey and immediately adjacent Pennsylvania and New York. The most important of these 

include studies by Baker and Buddington (1970), Buckwalter (1959, 1962), Dodd (1965), Drake (1969), Hague and 

others (1956), Hotz (1953), Offield (1967), Sims (1958), 

and Young (1971, 1972, 1978). Most of these workers 

abandoned the classic formations in favor of more precise 

lithologic units. 

More recent work (Drake, 1984) has shown that most 

of the intrusive rocks in the New Jersey Highlands belong to 

three suites: (1) hornblende granite, microperthite alaskite, 

and related rocks; (2) quartz-poor clinopyroxene-bearing 

rocks generally called syenite, and related clinopyroxenebearing granite; and (3) microantiperthite-bearing alaskite 

of complex origin. Much less abundant postkir.ematic 

Mount Eve Granite crops out in the Unionville, Pine Island, 

Hamburg, Wawayanda, and Newton East quadrangles 

(Drake and others, chap. C, this vol.) (fig. A2). 

Drake ( 1984) redefined the name "Byram" to include 

the hornblende granite and associated rocks in a Byram 

Intrusive Suite. Although it was recognized in 1984 that the 

clinopyroxene rocks constitute a distinct suite of rocks, they 

were not formally named, as their relation to the Byram was 

uncertain. Recently, geologic mapping of all the 7 .5-minute 

quadrangles in the New Jersey Highlands has been completed for the new geologic map of New Jersey. Although 

more detailed chemical work will be necessary to clearly 

establish the petrogenetic relation of the clinopyroxenebearing rocks to the Byram, it is clear that they constitute a 

distinct intrusive suite and deserve a formal name. They are 

here named the Lake Hopatcong Intrusive Suite for their 

abundance in the Lake Hopatcong area in the Stanhope and 

Dover 7 .5-minute quadrangles, New Jersey (fig. A2). 

BYRAM INTRUSIVE SUITE 

Granitoid rocks consisting of quartz, microperthite, 

and oligoclase and containing varying amounts of mafic 

minerals (as much as 10 percent) crop out throughout the 

Reading Prong and constitute the Byram Intrusive Suite. 

The Lake Hopatcong Intrusive Suite (Middle Proterozoic) of the New jersey Highlands A 1 
N 

EXPLANATION 

Grenville Province 

Outliers of rocks 

(older than 1 billion years) 

0 200 MILES I I I I I 

0 300 KILOMETERS 

Figure A 1. Distribution of rocks older than 1 billion years in Eastern North America. 

LR, Long Range; C, Chain Lakes massif; G, Green Mountain massif; A, Adirondack 

massif; B, Berkshire massif; R, Reading Prong; H, Honey Brook upland; AW, 

Avondale-West Chester massif; BD, Baltimore "gneiss domes"; SM, Shenandoah 

massif; S, Sauratown Mountains window; FBM, French Broad massif; SA, Salem 

Church anticline; and P, Pine Mountain window. Modified from Drake (1984). 

They occur in regionally comformable sheets, but locally 

cut across the structure of the older rocks. They are 

interpreted to have been synkinematically emplaced during 

the Grenville orogeny (Drake, 1969, 1984; Rankin and 

others, 1989, in press). These rocks are described below to 

allow comparison with the rocks of the Lake Hopatcong 

Intrusive Suite. 

The Byram rocks are medium- to coarse-grained, 

pink to buff to bronze, gneissoid to indistinctly foliated 

granitoids and sparse granite gneiss. Petrographically, the 

A2 Contributions to New Jersey Geology 

Byram consists of four different rock types: hornblende 

granite, alaskite, biotite granite, and hornblende syenite. 

The potassic feldspar is largely microcline microperthite, 

although some rocks contain microcline. The hornblende is 

largely ferrohastingsite. Regionally, the bulk of the rocks 

are monzogranite and syenogranite, although syenite and 

quartz syenite are fairly common, and alkali feldspar granite 

and quartz monzonite occur in some places (Drake, 1984). 

Drake (1984) showed that rocks mapped as Byram 

have a similar chemistry from the southwestern end of the 
U PI 

NEW YORK 

0 10 20 MILES 

~---.-~--,--J 

0 10 20 30 KILOMETERS 

N 

A 

NE 

pp 

8 

NEW JERSEY 

E CNG BV 

R FL 

Figure A2. Distribution of Middle Proterozoic rocks of the Reading Prong in New jersey and immediately adjacent 

New York. Quadrangles (7.5-minute) are as follows: R, Riegelsville; F, Frenchtown; FL, Flemington; E, Easton; BL, 

Bloomsbury; HB, High Bridge; CN, Califon; G, Gladstone; BV, Bernardsville; B, Banger; BE, Belvidere; W, 

Washington; H, Hackettstown; C, Chester; M, Mendham; MO, Morristown; BT, Blairstown; T, Tranquility; S, 

Stanhope; DO, Dover; BN, Boonton; PP, Pompton Plains; NE, Newton East; FR, Franklin; N, Newfoundland; WN, 

Wanaque; RM, Ramsey; HA, Hamburg; WA, Wawayanda; GL, Greenwood Lake; SL, Sloatsburg; U, Unionville; 

and PI, Pine Island. Place mentioned in text: LH, Lake Hopatcong area. The complexities of the Byram and Lake 

Hopatcong Intrusive Suites prevent them from being shown on a map at this scale. 

Reading Prong in Pennsylvania at least to the Hudson River 

in New York, a distance of about 121 mi (miles). Six new 

analyses of Byram rocks are presented in table AI. Chemically, the Byram rocks are granite or quartz monzonite (fig. 

A3). Drake (1984) pointed out that the chemistry of some of 

the Byram rocks in New Jersey suggests that they are 

hybrids. The samples plotting as trondhjemite, tonalite, and 

off the diagram (fig. A3) are also probably hybrids. 

Rocks of the Byram Intrusive Suite are much more 

abundant in the southwestern part of the Reading Prong than 

in the eastern part of New Jersey and adjacent New York. 

The Byram has an upper intercept Pb-U age of about 1090 

Ma (Drake and others, chap. D, this vol.). The Byram is 

thought to have resulted from anatectic melting at a depth 

greater than the present erosion surface, because there is no 

evidence of melt generation in outcrop. 

The Lake Hopatcong Intrusive Suite (Middle Proterozoic) of the New Jersey Highlands A3 
Table A 1. Chemical analyses and CIPW norms of rocks 1 of 

the Byram Intrusive Su ite 

[In weight percent. Dashes indicate not present] 

2 3 4 5 6 

Chemical analyses 

Si02 67.6 77.5 66.3 71.2 64.6 68 .6 

Al20 3 13.4 10.0 17.0 13.9 12.7 14.0 

Fe20 3 3.4 1.0 1.5 1. 1 3.9 3.81 

FeO 2.7 1.8 2.6 2.6 5.9 2.0 

MgO .56 1.0 .66 .34 .19 .32 

CaO 2.0 1.5 2.3 1.8 2.3 .8 

Na20 3.0 .82 5.8 2.9 3.5 3.75 

K20 4.4 4.5 1.8 5.6 4.2 5.31 

H20+ .32 .98 .66 .52 .48 .63 

H2o- .2 .32 .3 .07 .07 .06 

Ti02 .87 .46 1.0 .45 .62 .5 

P20s .15 .1 .2 .11 .09 .09 

MnO .06 .04 .05 .05 .35 .05 

C02 .03 .04 .08 .04 .05 .03 

Total 98 .69 100.06 100.25 100.68 98.95 99.95 

CIPW norms 

Quartz 29.6 51.2 19.7 27.4 21.2 24. 8 

Orthoclase 26.7 27.2 10.6 33.4 25 .6 31.7 

Albite 26.2 7.3 49 .2 24.6 30.4 32.0 

Anorthite 9.2 6.7 10.6 8.1 6.1 3.1 

Corundum .2 1.2 1.7 .9 

Diopside 1.6 4.2 3.6 1.9 3.9 .8 

Hypersthene .7 2.0 5.4 

Magnetite 5.1 1.4 2.1 1.6 5.8 5.3 

Ilmenite 1.7 .9 2.0 .9 1.2 .9 

Apatite .3 .3 .3 .3 .3 .3 

Hematite .2 

Total 101.3 100.4 99.8 100.2 99 .9 100.0 

1

Descriptions and locations of rocks are as follows: 

1. Hornblende granite from outcrops on east side of northbound 

lanes of N.J. Route 15 about 0.2 mile south of Tierney's Comer, Dover 

7.5-minute quadrangle , N.J. Chemically, the rock is quartz monzonite. 

Rapid rock analysis by L. Mei, U.S. Geological Survey. 

2. Hornblende granite from outcrops on southbound lane of N.J. 

Route 15 about 0.35 mile south of intersection with Sparta Road, Newton 

East 7.5-minute quadrangle, N.J. The rock has a "messy" appearance, 

contains abundant fluorite , and does not plot in a named field on the 

O'Connor (1965) normative feldspar plot. Same analyst as 1. 

3. Hornblende granite from outcrops along west bank of Ravine 

Lake at the dam abutment, Gladstone 7 .5-minute quadrangle, N.J. 

Chemically, the rock is trondhjemite. Same analyst as 1. 

4. Hornblende granite from outcrops on ridge nose along unnumbered road about 0.85 mile southwest of the village of Echo Lake, 

Newfoundland 7.5-minute quadrangle, N.J. Chemically, the rock is quartz 

monzonite. Rapid rock analysis by H. Smith, U.S. Geological Survey. 

5. Hornblende granite from outcrops along unnumbered road about 

0.55 airline mile N. 25° W. from Seneca Lake, Newton East 7.5-minute 

quadrangle, N.J. Chemically, the rock is granite. Same analyst as 4. 

6. Magnetite alaskite from outcrops along unnumbered road about 

1.3 airline miles from Califon, Califon 7.5-minute quadrangle , N.J. 

Chemically, the rock is granite. Rapid rock analysis by J. Taggart, A. 

Bartel, and D. Siems, U.S. Geological Survey. 

A4 Contributions to New Jersey Geology 

Trondhjemite 

An 

. . .. . . AbL-__________ _L_G_ra_n_it_e ________ ·~:----------~--JQr 

Figure A3. Normative feldspar plot (O'Connor, 1965) of 

rocks of the Byram Intrusive Suite. Data from Drake (1984) 

and this study. 

LAKE HOPATCONG INTRUSIVE SUITE 

Rocks of the clinopyroxene-bearing, quartz-poor 

Lake Hopatcong Intrusive Suite (here named) are characterized by mesoperthite or microantiperthite and were first 

mapped as such by Baker and Buddington (1970). Such 

rocks were recognized, however, by Hague and others 

(1956), who called them Type III Byram gneiss. In addition, Sims (1958) recognized a sheet of pyroxene granite in 

the Boonton quadrangle (fig. A2), but included it in his 

hornblende granite. Young (1971, 1972, 1978) has made 

special studies of these rocks. 

Rocks of the Lake Hopatcong Intrusive Suite are most 

abundant in the Stanhope, Franklin, Dover, and Wawayanda quadrangles (fig. A2). At one time it was thought they 

did not occur south of the Green Pond syncline (fig. A2). 

However, our work shows that they occur throughout the 

New Jersey Highlands, in the High Bridge, Califon, Hackettstown, Chester, Tranquility, Mendham, Pompton Plains, 

and Newfoundland quadrangles, pyroxene granite being 

much more abundant than quartz-poor varieties away from 

the Lake Hopatcong area. Lake Hopatcong rocks have not 

been recognized in the Hudson Highlands, although Dodd 

( 1965) reported that two specimens of Storm King Granite 

from Bear Mountain, N.Y., contain less than 1 percent 

clinopyroxene, but contain neither mesoperthite nor 

microantiperthite. Neither pyroxene granite nor pyroxene 

syenite have been recognized in Pennsylvania. 

Rocks of the Lake Hopatcong Intrusive Suite are 

medium to medium coarse grained, buff to greenish gray, 

and gneissoid to indistinctly foliated. They are composed 

largely of mesoperthite or microantiperthite, quartz, oligoclase, and clinopyroxene (ferrohedenbergite). The rocks 
0 

Figure A4. Quartz-alkali feldspar-plagioclase plot (Streckeisen, 1976) of rocks of the Lake Hopatcong Intrusive 

Suite. Data from Baker and Buddington (1970), Drake 

(1984, unpub.), Hague and others (1956), and Young (1971, 

1972, 1978). 

invariably contain titanite and trace amounts of sulfide. 

Petrographically, the quartz-poor rocks range from quartz 

monzodiorite to quartz-alkali feldspar syenite and alkali 

feldspar syenite (fig. A4). The granites range from granodiorite to alkali feldspar granite (fig. A4). Abundant chemical and modal data have been presented by Baker and 

Buddington (1970), Drake (1984), and Young (1978). 

Additional chemical data are given in table A2. Chemically, 

the rocks are trondhjemite and granite (fig. AS), the bulk of 

An 

Figure AS. Normative feldspar plot (O'Connor, 1965) of 

rocks of the Lake Hopatcong Intrusive Suite. Data from 

Drake (1984), Young (1978), and this study. 

Table A2. Chemical analyses and CIPW norms of rocks 1 of 

the Lake Hopatcong Intrusive Suite 

[In weight percent. Dashes indicate not present.] 

2 3 4 

Chemical analyses 

Si02 

Al20 3 

Fe20 3 

FeO 

MgO 

CaO 

N~O 

K20 

H2o+ 

H20-

Ti02 

PzOs 

MnO 

C02 

64.5 

17.8 

1.1 

1.4 

1.4 

2.5 

7.1 

3.0 

.65 

.21 

.42 

.13 

.04 

.02 

74.4 

12.6 

1.82 

1.0 

.24 

.89 

4.42 

3.79 

.15 

.08 

.29 

.05 

.02 

.02 

Total 100.27 99.77 

Quartz 5.3 32.5 

Orthoclase 17. 8 22. 2 

Albite 60.3 37.7 

Anorthite 7.8 3.6 

Corundum 

Wollastonite 

Diopside 3.1 .6 

Hypersthene 3.0 

Magnetite 1.6 2.3 

Ilmenite .8 .6 

Apatite .3 .3 

Hematite .2 

Total 100.0 100.0 

68.6 

14.0 

3.81 

2.0 

.32 

.80 

3.75 

5.31 

{.69 

.50 

.09 

.05 

.03 

73.5 

12.2 

4.1 

1.3 

.24 

1.69 

4.58 

2.01 

{.08 

.40 

.06 

.04 

99.95 100.2 

CIPW norms 

24.9 35.7 

31.7 11.7 

32.0 38.8 

3.1 7.0 

.9 

.8 .4 

.4 

5.3 3.0 

.9 .8 

.3 .3 

.2 2.1 

100.1 100.2 

5 

68.9 

14.1 

3.49 

1.3 

.26 

1.27 

4.65 

4.9 

{.16 

.37 

.06 

.06 

6 

65.5 

14.3 

4.22 

2.6 

.49 

2.4 

4.65 

4.83 

{.08 

.60 

.11 

.08 

7 

61.3 

16.1 

5.1 

3.1 

.77 

2.4 

5.74 

4.37 

{.07 

.99 

.18 

.13 

99.52 99.86 100.25 

21.0 17.3 7.3 

28.9 28.4 26.1 

39.8 39.3 48.7 

3.1 3.9 5.0 

.4 1.3 .4 

1.3 3.3 4.1 

3.2 6.0 7.4 

.8 1.2 2.1 

.3 .3 .3 

1.3 

100.1 101.0 101.4 

1

Descriptions and locations of rocks are as follows: 

1. Pyroxene granite from outcrops along Peapack Brook about 1 

mile north-northwest of St. Bernardo School, Gladstone 7 .5-minute 

quadrangle, N.J. Chemically, the rock is trondhjemite. Rapid rock analysis 

by L. Mei, U.S. Geological Survey. 

2. Pyroxene granite from outcrops on east side of north-trending 

road 200 feet north of intersection with east-trending road 1 ,000 feet west 

of Payson Lakes Village, Pompton Plains 7.5-minute quadrangle, N.J. 

Chemically, the rock is granite. Rapid rock analysis by J. Taggart, A. 

Bartel, and D. Siems, U.S. Geological Survey. 

3. Pyroxene alaskite from outcrops on east side of northwesttrending road 1, 100 feet northwest of intersection with northeast-trending 

road about 1.3 miles west of Lower Valley, Califon 7.5-minute quadrangle, N.J. Chemically, the rock is granite. X-ray fluorescence analysis by 

Nuclear Activation Services, Inc., Ann Arbor, Mich. 

4. Pyroxene granite from outcrop on west side of road 0.45 mile 

north of road intersection 600 feet west of Hudson Maxim School, 

Hopatcong, Stanhope 7 .5-minute quadrangle, N.J. Chemically, the rock is 

trondhjemite. Same analyst as 3. 

5. Pyroxene granite from outcrop at second right-angle bend in 

unimproved road 1,000 feet north of northern limit of Hopatcong Hills, 

Stanhope 7.5-minute quadrangle, N.J. Chemically, the rock is granite. 

Same analyst as 3. 

6. Pyroxene-quartz syenite from outcrop at road intersection 1,750 

feet northwest of Byram Cove, Stanhope 7.5-minute quadrangle, N.J. 

Chemically, the rock is syenite. Same analyst as 3. 

7. Pyroxene syenite from outcrop along west-bound lane of 

Interstate 80 900 feet east of Route 206 interchange. Chemically, the rock 

is syenite. Same analyst as 3. 

The lake Hopatcong Intrusive Suite (Middle Proterozoic) of the New Jersey Highlands AS 
K2o~----------------------------------~FeO+ Na 0L-----------------------------------~cao 

MgO+MnO 

A B 

Figure A6. Plots comparing the bulk chemistry of the Lake Hopatcong (35 analyses) and Byram (40 analyses) Intrusive 

Suites. Data from Baker and Buddington (1970), Drake (1969, 1984, this study), and Young (1978). A, Modified A-K-F plot; 

B, Na20-K20-Ca0 plot. 

the granites being more sodic than those of the Byram. 

Granitic and quartz-poor phases commonly are found in the 

same outcrop, and map units are defined by the major phase 

present. This being the case, neither granite nor syenite is 

formally named. 

The relation of the Lake Hopatcong Intrusive Suite to 

the Byram Intrusive Suite is a major problem in New Jersey 

Highlands geology. Baker and Buddington (1970) suggested that the pyroxene-bearing rocks resulted from the 

Q 

A B 

desilication of Byram magma. This would not appear to be 

the case, as there is as much, if not more, amphibolite 

associated with mapped rocks of the Byram that are not 

desilicated. Drake (1984) presented chemical data for 

microperthite alaskite and amphibolite from the same outcrop, the alaskite containing a normal amount of quartz. In 

fact, Buckwalter (1959, 1962) and Drake (1969, 1984) 

suggested that some of the Byram hornblende granite is 

amphibolite granitized by alaskitic fluids. 

Q 

Figure A7. Plots comparing normative mineralogy of rocks of the Lake Hopatcong (35 analyses) and Byram (40 

analyses) Intrusive Suites. Data from Baker and Buddington (1970), Drake (1969, 1984, this study), and Young (1978). 

A, Q-Ab-Or plot; B, Q-Or-Ab+An plot. 

A6 Contributions to New Jersey Geology 
Table A3. Fe-Mg ratios of some rocks of the Lake Hopatcong and Byram Intrusive Suites i 

[Data from Baker and Buddington (1970), Drake (1984), and this study] 

Lake Hopatcong Byram 

38.0 18.3 

26.2 16.7 

23.1 15.2 

22.6 12.9 

22.5 10.0 

22.1 9.3 

22.0 7.5 

21.1 6.2 

18.4 6.0 

18.3 5.5 

18.2 4.1 

15.5 3.9 

13.9 3.7 

11.8 3.5 

10.5 2.8 

9.0 2.6 

8.3 2.3 

8.2 2.2 

1.8 2.1 

Median 18.3 Median 5.5 

Mean 17.4 Mean 7.1 

Rhett (1975) suggested that all the granite in the New 

Jersey Highlands originally contained pyroxene and that 

retrograde reactions south of the Green Pond syncline (fig. 

A2) altered the pyroxene to hornblende and quartz. This 

would not appear to be the case, as there is abundant 

hornblende granite north of the Green Pond syncline as well 

as east and west of the Lake Hopatcong area. In addition, 

the rocks south of the Green Pond syncline appear to be at 

higher metamorphic grade than those to the north (Offield, 

1967; Drake, 1984). 

The Lake Hopatcong and Byram Intrusive Suites 

differ in chemistry (fig. A6, table A3), normative mineralogy (fig. A7), and petrography. They clearly are two 

entities, but their petrogenetic relations await the completion of more sophisticated chemical studies. 

REGIONAL RELATIONS 

The similarity between the rocks of the Reading 

Prong and those of the Adirondacks has been recognized for 

many years (Engel, 1956; Sims, 1958; Drake, 1969, 1984; 

Baker and Buddington, 1970). Chemically, the hornblende 

granites and alaskites of the Adirondacks (fig. A8) are 

similar to many rocks of the Byram Intrusive Suite (fig. 

A3), although the Byram rocks have a much more variable 

composition. The two suites are also similar on an AFM 

plot (fig. A9), although the Byram rocks occupy a more 

extensive field. Rocks of the Lake Hopatcong Intrusive 

An 

Figure A8. Normative feldspar plot (O'Connor, 1965) of 

hornblende granite and alaskite from the Adirondack 

massif. All rocks are granite. Data from Buddington (1939, 

1957) and Buddington and Leonard (1962). 

Suite have some similarities to the quartz syenites of the 

Adirondacks (fig. A10), although the Adirondack rocks 

typically contain more normative anorthite and lack the 

range of composition of the Lake Hopatcong rocks. 

Rankin, Drake, and Ratcliffe (in press) have categorized the igneous rocks of the Reading Prong, Berkshire 

massif, and Green Mountain massif as defining pre kineAdirondack 

massif 

F 

AL-------------------------------------~M 

Figure A9. AFM plot comparing rocks of the Byram Intrusive Suite with hornblende granite and alaskite from the 

Adirondack massif. Data from Buddington (1939, 1957), 

Buddington and Leonard (1962), Drake (1984), and this 

study. 

The Lake Hopatcong Intrusive Suite (Middle Proterozoic) of the New Jersey Highlands A7 
An 

Figure A 10. Normative feldspar plot of quartz syenites 

from the Adirondack massif. Data from Buddington (1939, 

1957) and Buddington and Leonard (1962). 

matic, synkinematic, and postkinematic sequences. The 

rocks of the Byram Intrusive Suite are similar chemically to 

the synkinematic rocks of both the Berkshire and Green 

Mountain massifs. No pyroxene-bearing granites or syenites, however, are known in those massifs. It would appear, 

then, that the Reading Prong is more similar to the Adirondacks than to the Berkshire and Green Mountain massifs. 

Interestingly, the prekinematic and postkinematic 

sequences in the Reading Prong, Berkshire massif, and 

Green Mountain massif are also similar (Rankin and others, 

in press). An understanding of the Middle Proterozoic 

geology of the Appalachian orogen is beginning to emerge. 

REFERENCES CITED 

Baker, D.R., and Buddington, A.F., 1970, Geology and magnetite deposits of the Franklin quadrangle and part of the 

Hamburg quadrangle, New Jersey: U.S. Geological Survey 

Professional Paper 638, 73 p. 

Bay ley, W. S. , 1941 , Pre-Cambrian geology and mineral resources 

of the Delaware Water Gap and Easton quadrangles, New 

Jersey and Pennsylvania: U.S. Geological Survey Bulletin 

920, 96 p. 

Buckwalter, T.V., 1959, Geology of the Precambrian rocks and 

Hardyston Formation of the Boyertown quadrangle: Pennsylvania Geological Survey, 4th ser., Geological Atlas 197, 

15 p. 

---1962, The Precambrian geology of the Reading 15-minute 

quadrangle: Pennsylvania Geological Survey, 4th ser., 

Progress Report 161, 49 p. 

Buddington, A.F., 1939, Adirondack igneous rocks and their 

metamorphism: Geological Society of America Memoir 7, 

354 p. 

A8 Contributions to New jersey Geology 

---1957, Interrelated Precambrian granitic rocks, northwest 

Adirondacks, New Y~: Geological Society of America 

Bulletin, v. 68, p. 291-306. 

Buddington, A.F., and Leonard, B.F., 1962, Regional geology of 

the St. Lawrence County magnetite district, northwest 

Adirondacks, New York: U.S. Geological Survey Professional Paper 376, 145 p. 

Dodd, R.T., Jr., 1965, Precambrian geology of the Popolopen 

Lake quadrangle, southeastern New York: New York State 

Museum and Science Service Map and Chart Series 6, 39 p. 

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. 51-131. 

---1984, The Reading Prong of New Jersey and eastern 

Pennsylvania: An appraisal of rock relations and chemistry of 

a major Proterozoic terrane in the Appalachians, in Bartholomew, M.J., ed., The Grenville event in the Appalachians 

and related topics: Geological Society of America Special 

Paper 194, p. 75-109. 

Drake, A.A., Jr., Hall, L.M., and Nelson, A.E., 1988, Basement 

and basement -cover relation map of the Appalachian orogen 

in the United States: U.S. Geological Survey Miscellaneous 

Investigations Map I-1655, scale 1: 1 ,000,000. 

Engel, A.E.J., 1956, Apropos the Grenville, in Thompson, J.E., 

The Grenville problem: Royal Society Canada Special Publication 1, p. 74-98. 

Hague, J.M., Baum, J.L., Herrman, L.A., and Pickering, R.J., 

1956, Geology and structure of the Franklin-Sterling area, 

New Jersey: Geological Society of America Bulletin, v. 67, 

p. 434-474. 

Hotz, P.E., 1953, Magnetite deposits of the Sterling Lake, New 

York-Ringwood, New Jersey, area: U.S. Geological Survey 

Bulletin 982-F, p. 153-244. 

O'Connor, J.T., 1965, A classification for quartz-rich igneous 

rocks based on feldspar ratios: U.S. Geological Survey 

Professional Paper 525-B, p. B79-B84. 

Offield, T.W., 1967, Bedrock geology of the Goshen-Greenwood 

Lake area, New York: New York State Museum and Science 

Service Map and Chart Series 9, 78 p. 

Rankin, D.W., Drake, A.A., Jr., and Ratcliffe, N.M., in press, 

Proterozoic North American (Laurentian) rocks of the Appalachian orogen, in Reed, J.C., Jr., Bickford, M.E., Houston, 

R.S., Link, P.K., Rankin, D.W., Sims, P.K., and Van 

Schmus, W.R., Precambrian: Conterminous U.S. (The Geology of North America, v. C-2): Boulder, Colo., Geological 

Society of America. 

Rankin, D.W., Hall, L.M., Drake, A.A., Jr., Goldsmith, Richard, Ratcliffe, N.M., and Stanley, R.S., 1989, Proterozoic 

evolution of the rifted margin, in Hatcher, R.D., Jr., Thomas, W.A., and Viele, G.W., eds., The Appalachian and 

Ouachita regions (The Geology of North America, v. F-2): 

Boulder, Colo., Geological Society of America, p. 101-177. 

Rhett, D.W., 1975, Phase relationships and petrogenetic environment of Precambrian granites: Unpub. Ph.D. dissertation, 

Rutgers University (New Brunswick, N.J.), 157 p. 
Sims, P.K., 1958, Geology and magnetite deposits of the Dover 

district, Morris County, New Jersey: U.S. Geological Survey 

Professional Paper 287, 162 p. 

Spencer, A.C., Kummel, H.B., Wolff, J.E., Salisbury, R.D., and 

Palache, Charles, 1908, Franklin Furnace, New Jersey: U.S. 

Geological Survey Geologic Atlas of the United States, Folio 

161, 27 p. 

Streckeisen, Albert, 1976, To each plutonic rock its proper name: 

Earth Science Reviews, v. 12, p. 1-33. 

Young, D.A., 1971, Precambrian rocks of the Lake Hopatcong 

area, New Jersey: Geological Society of America Bulletin, v. 

82, p. 143-158. 

---1972, A quartz syenite intrusion in the New Jersey Highlands: Journal of Petrology, v. 13, p. 511-528. 

---1978, Precambrian salic intrusive rocks of the Reading 

Prong: Geological Society of America Bulletin, v. 89, 

p. 1502-1514. 

The Lake Hopatcong Intrusive Suite (Middle Proterozoic) of the New Jersey Highlands A9 

Chapter B 

The High Point Member (Upper Ordovician) 

of the Martinsburg Formation in Northern 

New Jersey and Southeastern New York 

By AVERY ALA DRAKE, jR. 

Prepared in cooperation with the 

New jersey Geological Survey 

U.S. GEOLOGICAL SURVEY BULLETIN 1952 

CONTRIBUTIONS TO NEW JERSEY GEOLOGY 

CONTENTS 

Abstract Bl 

Introduction Bl 

Bushkill Member B 1 

Ramseyburg Member B2 

Pen Argyl Member B4 

High Point Member B4 

Regional Relations B7 

References Cited B9 

FIGURES 

B 1. Generalized geologic map of parts of northern New Jersey and southeastern 

New York B2 

B2. Simplified geologic map of the High Point Member of the Martinsburg 

Formation B3 

B3. Schematic diagram showing the relation of the members of the Martinsburg 

Formation B4 

B4. Ideal sequence (the Bouma sequence) of structures in a turbidite bed B4 

B5-B10. Photographs showing: 

TABLE 

B5. Typical exposure of Ramsey burg Member of the Martinsburg 

Formation B6 

B6. Abundant load casts on the bottom of a Ramseyburg graywacke 

bed B7 

B 7. Scoured shale remnants on the top of a High Point graywacke 

bed B7 

B8. Rip-up clasts of shale in High Point graywacke B7 

B9. Outcrop of typical High Point BS 

B 10. Very large load casts in the High Point BS 

B 1. Classification of turbidite and other resedimented facies B5 

Contents Ill 

The High Point Member (Upper Ordovician) 

of the Martinsburg Formation in 

Northern New jersey and Southeastern New York 

By Avery Ala Drake, Jr. 

Abstract 

The High Point Member of the Martinsburg Formation is a unit of thick-bedded graywacke, amalgamated 

graywacke, and much less abundant dark-colored shale in 

northernmost New jersey and southeastern New York. It 

occurs stratigraphically above the Ramseyburg Member, 

as does the Pen Argyl Member in the Delaware Valley. 

Although probably of about the same age, these units are 

radically different sedimentologically. The muddy turbidites of the Pen Argyl were deposited in a densitystratified, anoxic basin, whereas the High Point is a 

sequence of high-energy turbidite facies Band less abundant facies C deposits. The High Point is a much more 

proximal deposit than the rocks of the Martinsburg to the 

southwest, and its character supports the concept based 

on paleocurrent information that the Martinsburg foreland basin was filled longitudinally from the northeast. 

INTRODUCTION 

The Martinsburg Formation is the fill in the Martinsburg foreland basin in the central Appalachians (Drake and 

others, 1989). In the Delaware Valley of New Jersey and 

Pennsylvania, the Martinsburg consists of three members, a 

lower Bushkill, a middle Ramseyburg, and an upper Pen 

Argyl, aggregating to a total thickness of about 14,000 ft 

(feet) (Drake and Epstein, 1967). This is the greatest 

thickness known from Virginia to New York, suggesting 

that the foreland basin is deepest here. This great thickness 

probably results from downbuckling due to the thrust load 

of the Hamburg klippe (Lash and Drake, 1984), following 

the concept of Jordan (1981). 

Geologic mapping at a scale of 1:24,000 (Drake and 

others, 1969, 1985; Drake and Lyttle, 1985; A.A. Drake, 

Jr., unpub. data) has traced the Bushkill and Ramseyburg 

Members into southeastern New York (fig. B1), and 

Manuscript approved for publication July 19, 1990. 

Epstein and Lyttle (1987) reported that the Bushkill Member can be recognized at least as far northeast as the 

Newburgh, N.Y., area. In southeastern New York, the 

Bushkill and Ramseyburg were miscorrelated with the 

Mount Merino Shale Member of the Normanskill Shale and 

Austin Glen Graywacke, units of the Taconic klippe, by 

Offield (1967). The Pen Argyl Member, on the other hand, 

disappears beneath the Silurian Shawangunk Formation just 

west of the Delaware River (Drake and Epstein, 1967). 

In northernmost New Jersey, a unit of thick-bedded 

graywacke and much less dark shale appears above the 

Ramseyburg (figs. B 1, B2). This unit is here named the 

High Point Member of the Martinsburg Formation, for 

typical exposures at High Point State Park and south along 

New Jersey Route 23 to Colesville, Port Jervis South 

quadrangle, Sussex County, N.J. (fig. B2). 

The Bushkill, Ramseyburg, and Pen Argyl Members 

of the Martinsburg Formation are discussed briefly below to 

establish their relation to the High Point and to point up the 

changes in the foreland basin between the Delaware Valley 

and southeastern New York. The relation of these members 

is shown in figure B3. 

BUSHKILL MEMBER 

In the Delaware Valley, the Bushkill Member overlies the euxinic cement rock facies of the Jacksonburg 

Limestone, the contact being marked by a decrease in 

carbonate and an increase in pelitic material (Drake, 1969). 

The basal Bushkill is black to dark-gray slate, reflecting the 

continuing stagnant conditions of the foreland basin at this 

time. Within a short vertical distance, thin-bedded slate and 

siltstone appear. Few beds exceed 4 in (inches) in thickness, 

and most are less than half an inch thick. Silt-shale ratios 

range from about 1:3 to 1:6, the lithologic change forming 

"ribbons" on slaty cleavage surfaces. In terms of Bouma's 

(1962) turbidite model (fig. B4), most beds lack one or 

more of the basal units and can be classed as Tb-e• Te-e• or 

Td-e turbidites. Te-e beds appear to be most common. These 

The High Point Member of the Martinsburg Formation in Northern New jersey and Southeastern New York 81 
PORT JERVIS 

NORTH 

BRANCHVILLE 

YANKEE LAKE 

Omu 

Older 

rocks 

Hamburg 

• 

HAMBURG 

DS 

MIDDLETOWN 

Middletown 

• 

Omu 

PINE ISLAND 

0 

I 

0 

I 

5 

5 

I 

I 

N 

A 

10 MILES 

I 

10 KILOMETERS 

Figure 81. Generalized geologic map of parts of northern New jersey and southeastern New York showing distribution of the Martinsburg Formation and location of 

7.5-minute quadrangles. Rock units: DS, undivided Silurian and Devonian rocks; 

Omu, Martinsburg Formation undivided; Omhp, High Point Member of Martinsburg Formation; Omr-Omb, Bushkill and Ramseyburg Members of Martinsburg 

Formation undivided. Sources of data: New jersey, detailed geologic mapping by 

A.A. Drake, Jr.; New York, Fisher and others (1970). 

rocks are assigned to turbidite facies D of Mutti and Ricci 

Lucchi (1978) and Walker and Mutti (1973) (table B1). 

These rocks, then, are classic "distal" turbidites. 

In the Delaware Valley, the Bushkill is about 4,000 ft 

thick. To the northeast, in the Unionville quadrangle (fig. 

B 1), it is about 1,500 ft thick. The euxinic basal part of the 

unit thickens, and turbidites first appear higher in the 

Bushkill. The changes in thickness and facies are difficult to 

track because much of the Martinsburg is covered by 

klippen of carbonate rocks in north-central New Jersey 

(Drake and others, 1985; Drake and Lyttle, 1985; A.A. 

Drake, Jr., unpub. data). 

The Bushkill is difficult to date precisely, as its 

contained graptolite fauna is sparse, represents a very 

82 Contributions to New Jersey Geology 

restricted and extreme biofacies, and contains only a few 

species which are both hard to identify and long ranging. It 

is younger than the Jacksonburg Limestone, so its lower 

part is probably of Rocklandian to Kirkfieldian (Llandeilian) age, and on the basis of graptolites, the unit ranges 

from Kirkfieldian (Llandeilian) to Edenian (Caradocian) in 

age (Drake and others, 1989). 

RAMSEYBURG MEMBER 

The Bushkill grades up into the Ramseyburg Member, a sequence of alternating beds of slate and thin- to 

thick-bedded graywacke and graywacke siltstone (fig. B5). 

The graywacke beds range from less than an inch to as 
410,---------------------------------------~~~---------r-------------------.------------~-.ro 

22' 

30" 

41° 

17' 

30" 

High Point 

State Park 

N 

A 

~;;)' ' su 

Ss 

Omhp 

Omr 

Omhp 

0 2 MILES 

0 2 KILOMETERS 

41°L_~------~--L_ ____________________________ L-----------------------------------------------~ 

15' 

Figure 82. Simplified geologic map of the High Point Member of the Martinsburg Formation in the Unionville 

quadrangle, New York-New Jersey, and the Port Jervis South quadrangle, New Jersey-New York. Ss, Shawangunk 

Formation (Middle Silurian); Omhp, High Point Member of Martinsburg Formation (Upper Ordovician); Omr, 

Ramseyburg Member of Martinsburg Formation (Upper Ordovician). A, B, C, and D: localities mentioned in text. F: 

graptolite locality. 

The High Point Member of the Martinsburg Formation in Northern New Jersey and Southeastern New York 83 
c: 

0 

·.;:::; 

co 

Eastern 

Pennsylvania 

Pen Argyl 

Member 

E 

01------~ 

u. 

El 

::l 

..c 

C/) 

c: 

·-e 

co 

New Jersey 

Ramseyburg Member 

~ Bushkill Member 

Southeastern 

New York 

Jacksonburg Limestone Balmville Limestone 

Figure 83. Schematic diagram showing the relation of the 

members of the Martinsburg Formation from eastern 

Pennsylvania to the Unionville quadrangle in southeastern 

New York. 

much as about 5 ft in thickness and average about 1 ft. The 

beds are very continuous in outcrop. Texturally, most of the 

graywacke is fine grained, but medium-grained sandstone 

occurs at places. Many beds contain the complete Bouma 

(1962) sequence (fig. B4), but basal cutout sequences, 

particularly Te-e sequences, are most common. Many beds 

contain abundant sole marks (fig. B6). It is difficult to 

assign the Ramseyburg to a turbidite facies of Mutti and 

Ricci Lucchi (1978) and Walker and Mutti (1973). The 

rocks have many characteristics of facies C (table B 1), but 

bed thickness and continuity, grain size, and the basal 

cutout sequences are more typical of facies D (table B 1). 

Certainly, the rocks of the Ramsey burg are much more 

"proximal" than those of the Bushkill Member, but they are 

not typical of the "proximal" turbidites of facies C (table 

B1). 

The Ramsey burg is about 2, 800 ft thick in the 

Delaware Valley (Drake and Epstein, 1967) and about 

3,500 ft thick in the Unionville quadrangle (fig. B1). As 

with the Bushkill, the change is difficult to track because of 

the carbonate klippen in north-central New Jersey. 

The Ramseyburg is also difficult to date. Drake and 

others (1989) estimate that it is Edenian (Caradocian) in 

age. 

PEN ARGYL MEMBER 

In the Delaware Valley the Ramseyburg grades up 

into the Pen Argyl Member, a unit consisting of laminated 

graywacke siltstone and slate, thick-bedded slate, and black 

slate. The beds in the laminated sequence rarely exceed a 

foot in thickness, although some are as much as 3 ft thick. 

The black slate beds range from less than an inch to 20 

inches in thickness, whereas the thick-bedded slate is 

commonly 5 ft thick, though intervals as thick as 30 ft have 

84 Contributions to New Jersey Geology 

. . : .··. . .· .. : .··. ..... . . ·. · ... ... 

... 

• • • • • 0. 

Grain 

size 

.... 

'Cii 

-6 

c: 

co 

(/) 

"C 

c: 

co 

(/) 

Q) 

C/) 

co 

..c 

e 

d 

c 

b 

Bouma (1962) 

divisions 

I ntertu rbidite 

(generally 

shale) 

Upper parallel 

laminae 

Ripples, wavy 

or convoluted 

laminae 

Plane parallel 

laminae 

Massive, 

graded 

Figure 84. Ideal sequence (the Bouma sequence) of structures in a turbidite bed (modified from Middleton and 

Hampton, 1973). 

been recognized. This rock is commercially exploited for 

roofing slate. Both the laminated rocks and the thickbedded slate are turbidites, but neither group has a predictable or cyclic arrangement of bedforms similar to that of 

sand turbidites (Bouma, 1962), and both groups are interpreted by Lash ( 1987) to be muddy turbidites deposited in 

an anoxic basin. 

The Pen Argyl is estimated to be as much as 6,000 ft 

thick in the Delaware Valley (Drake and Epstein, 1967). It 

does not crop out west of Hawk Mountain in Pennsylvania 

or east of the Delaware River. 

The Pen Argyl contains graptolites of Edenian (Caradocian) age near its upper contact (Epstein and Berry, 

1973). 

HIGH POINT MEMBER (HERE NAMED) 

The unit herein called the High Point Member was 

first recognized as a separate Martinsburg entity by Peter 

Lyttle (oral commun., 1983). It is characterized by thick or 

thick-appearing graywacke beds that have resulted from 

sedimentary amalgamation. At places, the graywacke contains intervals or interbeds of dark-colored shale. Much of 

the graywacke has a siliceous cement and typically contains 

rip-up clasts of dark-colored shale. The High Point lies 
Table 81. Classification of turbidite and other resedimented facies 

[Modified from Walker and Mutti, 1973] 

Facies 

A ........................... . 

AI·············· ··· ······ 

Az 

A3 ...................... . 

A4 ...................... . 

B ............................ . 

BI ..... .... .. ..... ....... . 

Bz ....................... . 

C ............................ . 

D ···························· 

E .............. ....... ....... . 

F ............................ . 

G ........................... . 

Description 

Coarse-grained sandstones and conglomerates. 

Disorganized conglomerates. 

Organized conglomerates. 

Disorganized pebbly sandstones. 

Organized pebbly sandstones. 

Medium-fine- to coarse-grained sandstones. 

Massive sandstones having "dish" structure. 

Massive sandstones not having "dish" structure. Most beds lack alternating 

parallel lamination but may contain crude, subparallel, faint stratification. 

Beds have a very high (> 10: 1) sand/shale ratio, indicating that sandstones 

are amalgamated; that is, beds are welded together without interbedded 

shales. Beds range from tens of centimeters to about 2 meters thick and 

have scoured bases, and most are lenticular. 

Medium- to fine-grained sandstones-classic "proximal" turbidites beginning with 

Bouma division a. Strata typically are sharp, flat based, and regularly bedded, 

and have good lateral continuity. Sandstones range from about 10 centimeters 

to 1 meter thick and have sand/shale ratios of about 5:1. Amalgamation is 

uncommon, and most sandstone beds grade up into shale (Bouma division e). 

Most beds in a sequence begin with Bouma division a. Parallel (Bouma divisions band d) and ripple cross-lamination (Bouma division c) is uncommon, 

and rock can typically be described as a Tae turbidite. Facies C is not sharply 

separated from Facies B2 , and there is a spectrum of beds between B2 and C. 

Fine- to very fine grained sandstones and siltstones-classic "distal" turbidites 

beginning with Bouma division b or c. Sandstone beds have sharp, flat bases, 

are prominently graded, and are about 1-10 centimeters thick. The sand/shale 

ratio is low, 1: 1 or less. Most sequences start with Bouma division b or c and 

can be described as Thede• Tbde• or Tcde turbidites, the Tcde being the model 

sequence. There is a gradation between turbidites of facies C and D. 

Similar to facies D, but has higher sand/shale ratios, thinner, more irregular 

beds, and more discontinuous beds in wedges and lenses. The tops of most 

sandstone beds are not graded but are in sharp contact with overlying shales. 

Facies is characterized by Tae turbidites. 

Chaotic deposits formed by downslope mass movements. 

Hemipelagic and pelagic shales and marl-silty or calcareous deposits having 

indistinct and poorly developed lamination or distinct parallel bedding and 

resulting from very dilute suspensions. 

above the Ramsey burg in an unknown manner. The contact 

occurs between rocks that were deposited in quite different 

sedimentary environments. It is placed at the first appearance of thick-bedded graywacke or amalgamated graywacke containing clasts of dark -colored shale. The contact 

is probably gradational, as Peter Lyttle (oral commun., 

1989) has reported that rocks like those herein called High 

Point are interbedded with rocks resembling the Ramseyburg in a unit informally called the graywacke at Pine Bush 

(Epstein and Lyttle, 1987) in the Pine Bush quadrangle, 

New York (fig. Bl). 

Tbc or Te-e (fig. B4) and have all the characteristics of 

turbidite facies D (table B1). The High Point in the nearest 

good exposure to the contact, locality D in figure B2, 

consists of three amalgamated beds having a total thickness 

of 57 in. Most of the graywacke is dark gray (N3) on fresh 

surfaces and weathers olive gray (5Y 4/1). Bed tops are 

marked by the scoured remnants of shale that is grayish 

black where fresh and pale yellowish brown (lOYR 6/2) 

where weathered (fig. B7). The graywacke also contains 

abundant rip-up clasts of shale (fig. B8), some of which are 

as long as 7 in. The graywacke beds here have graded bases 

Descriptions of important outcrops follow. The Ram- and parallel laminated tops, so are Tab turbidites (fig. B4). 

seyburg in the nearest good exposure to the contact, locality 

A in figure B2, is interbedded graywacke and slate in 

intervals 0.5 to 5 in thick. The rocks are Bouma sequence 

Another good exposure of High Point, locality B in 

figure B2, consists of 4 ft of graywacke, which is actually 

two amalgamated beds, the top of the lower bed being 

The High Point Member of the Martinsburg Formation in Northern New jersey and Southeastern New York 85 
Figure 85. Typical exposure of the Ramseyburg Member of the Martinsburg Formation. Hammer is 12.75 inches long. 

marked by sparse remnants of shale. Four feet of dark shale 

underlies the graywacke. 

Exceptional exposures of High Point occur at locality 

C in figure B2. In one exposure, a bed of graywacke is at 

least 63 in thick. Its bottom is not exposed, and there is no 

evidence of amalgamation. In another exposure, a 70-in bed 

is amalgamated to an 18-in bed below and a 24-in bed 

above. Grading was the only sedimentary structure noted, 

so the rocks here are T a turbidites. 

Few long exposures of High Point were found. One 

of the best (fig. B9) contains only a minor amount of shale. 

In other areas, such as in High Point State Park and along 

Interstate 84 (fig. B2), dark shale is fairly abundant. 

The High Point is characterized by abundant load 

casts, some of which are very large (fig. B10). Most of the 

rock in the High Point is silica cemented, but many beds in 

the lower part of the unit contain carbonate in their matrix. 

Much of the High Point can be assigned to turbidite 

facies B (table B 1), but other parts, particularly those that 

contain interbedded shale, are better assigned to turbidite 

facies C. In any case, the rocks were deposited in a much 

higher energy environment than the other parts of the 

Martinsburg Formation. 

86 Contributions to New Jersey Geology 

The High Point may be as much as 4,500 ft thick in 

the Unionville quadrangle, but this is only an estimate. 

Berry ( 1971) described four species of graptolites collected 

from the High Point 50-100 ft stratigraphically below the 

Shawangunk Formation along Interstate 84 in the Port 

Jervis South quadrangle (fig. B2). He assigned these 

graptolites to his Climacograptus spiniferus zone, suggesting that at least this part of the High Point is Edenian 

(Caradocian) in age. More recently, Parris and Cruikshank 

(in press) collected three specimens of Orthograptus 

quadrimucronatus from the High Point about 750 ft stratigraphically below the Shawangunk Formation along New 

Jersey Route 519 in the Port Jervis South quadrangle (fig. 

B2). It is, however, impossible to assign a zone or age on 

the basis of one species. It would appear, therefore, that at 

least the upper part of the High Point is the same age as the 

Pen Argyl Member in the Delaware Valley. 

The High Point is unconformably overlain by rocks of 

the Shawangunk Formation of probable Middle Silurian 

age. The low-angle unconformity is marked by an interval, 

less than 1 ft thick, of diamictite interpreted to be a colluvial 

deposit by Epstein and Lyttle (1987). 
Figure 86. Abundant load casts on the bottom of a Ramseyburg graywacke bed. Bed dips toward viewer and is 

overturned. Hammer is 12.75 inches long. 

REGIONAL RELATIONS 

McBride (1962), on the basis of paleocurrent indicators, first suggested that the Martinsburg foreland basin was 

filled from the northeast. Data reported herein support that 

Figure 87. Scoured shale remnants on the top of a High 

Point graywacke bed. Knife is 3.5 inches long. 

concept, as the Martinsburg lithology clearly becomes more 

proximal to the northeast. Much of the Bushkill Member is 

replaced by the turbidite facies C deposits of the Ramseyburg Member. The Bushkill-Ramseyburg sequence has 

been interpreted as unconfined sheet flows or as turbidites 

Figure 88. Rip-up clasts of shale in High Point graywacke. 

Knife is 3.5 inches long. 

The High Point Member of the Martinsburg Formation in Northern New jersey and Southeastern New York 87 
Figure 89. Outcrop of typical High Point. Two thin shale 

interbeds occur in the lower right of the photograph. The 

thin-bedded material in the upper part of the photograph 

is graywacke. Hammer is 12.75 inches long. 

deposited within wide, shallow channels (Lash, 1987). The 

high proportion of basal cutout sequences supports the latter 

concept. Much of the Bushkill-Ramseyburg interval in 

northernmost New Jersey and adjacent New York is 

replaced by the much more proximal turbidite facies B and 

lesser C High Point Member. Farther to the northeast in the 

Pine Bush quadrangle (fig. B 1), Ramseyburg-like rocks 

occur only within the High Point-like graywacke in the Pine 

Bush sequence (Epstein and Lyttle, 1987). Yet another 

Martinsburg unit, the shale and graywacke at Mamakating 

of Epstein and Lyttle (1987), occurs above the Pine Bush. 

Their brief description suggests that this unit was deposited 

in a lower energy environment than the High Point. The Pen 

Argyl Member in the Delaware Valley, the High Point, and 

the shale and graywacke at Mamakating (Berry, 1971) all 

contain graptolites of the Climacograptus spiniferus zone, 

suggesting that they all might be of about the same age, 

although they were deposited in radically different 

sedimentary environments. The Martinsburg would be an 

excellent field laboratory to study the evolution of 

foreland basins. 

Figure 810. Very large load casts in the High Point. Hammer is 12.75 inches long. 

88 Contributions to New Jersey Geology 
REFERENCES CITED 

Berry, W .B .N., 1971, Late Ordovician graptolites from southeastern New York: Journal of Paleontology, v. 45, p. 633-640. 

Bouma, A.H., 1962, Sedimentology of some flysch deposits: 

Amsterdam, Elsevier, 168 p. 

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. 51-131. 

Drake, A.A., Jr., and Epstein, J.B., 1967, The Martinsburg 

Formation (Middle and Upper Ordovician) in the Delaware 

Valley, Pennsylvania-New Jersey: U.S. Geological Survey 

Bulletin 1244-H, 16 p. 

Drake, A.A., Jr., Epstein, J .B., and Aaron, J .M., 1969, Geologic 

map and sections of parts of the Portland and Belvidere 

quadrangles, New Jersey-Pennsylvania: U.S. Geological 

Survey Miscellaneous Investigations Map 1-552, scale 

1:24,000. 

Drake, A.A., Jr., Kastelic, R.L., Jr., and Lyttle, P.T., 1985, 

Geologic map of the eastern parts of the Belvidere and 

Portland quadrangles, Warren County, New Jersey: U.S. 

Geological Survey Miscellaneous Investigations Map 

1-1530, scale 1:24,000. 

Drake, A.A., Jr., and Lyttle, P.T., 1985, Geologic map of the 

Blairstown quadrangle, Warren County, New Jersey: U.S. 

Geological Survey Geologic Quadrangle Map GQ-1585, 

scale 1:24,000. 

Drake, A.A., Jr., Sinha, A.K., Laird, Jo, and Guy, R.E., 1989, 

The Taconic orogen, in Hatcher, R.D., Jr., Thomas, W.A., 

and Viele, G.W., eds., The Appalachian-Ouachita orogen in 

the U.S. (The geology of North America, v. F-2): Boulder, 

Colo., Geological Society of America, p. 101-177. 

Epstein, J.B., and Berry, W.B.N., 1973, Graptolites from the 

Martinsburg Formation, Lehigh Gap, Pennsylvania: 

U.S. Geological Survey Journal of Research, v. 1, no. 1, 

p. 33-37. 

Epstein, J.B., and Lyttle, P.T., 1987, Structure and stratigraphy 

above, below, and within the Taconic unconformity, southeastern New York, in Waines, R.H., ed., New York State 

Geological Association annual meeting, 59th, Kingston, 

N.Y., November 6-8, 1987, Field trip guidebook, 

p. C1-C78. 

Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 1970, Geologic map of New York State, Lower Hudson sheet: New 

York State Museum and Science Service Map and Chart 

Series 15, scale 1:250,000. 

Jordan, T .E., 1981, Thrust loads and foreland basin evolution, 

Cretaceous, Western United States: American Association of 

Petroleum Geologists Bulletin, v. 65, p. 2506-2520. 

Lash, G.G., 1987, Sedimentology and possible paleooceanographic significance of mudstone turbidites and associated 

deposits of the Pen Argyl Member, Martinsburg Formation 

(Upper Ordovician), eastern Pennsylvania: Sedimentary 

Geology, v. 54, p. 113-135. 

Lash, G.G., and Drake, A.A., Jr., 1984, The Richmond and 

Greenwich slices of the Hamburg klippe in eastern Pennsylvania-Stratigraphy, sedimentology, structure, and plate tectonic implications: U.S. Geological Survey Professional 

Paper 1312, 40 p. 

McBride, E.F., 1962, Flysch and associated beds of the Martinsburg Formation (Ordovician), central Appalachians: Journal 

of Sedimentary Petrology, v. 32, no. 1, p. 39-91. 

Middleton, G.V., and Hampton, M.A., 1973, Sediment gravity 

flows; Mechanics of flow and deposition, in Middleton, 

G. V., and Bouma, A.H., co-chairmen, Turbidites and deepwater sedimentation: Los Angeles, Society of Economic 

Paleontologists and Mineralogists, Pacific Section, p. 1-38. 

Mutti, Emiliano, and Ricci Lucchi, F.R., 1978, Turbidites of the 

northern Apennines; Introduction to facies analysis: American Geological Institute Reprint Series 3, p. 125-166. 

Offield, T. W., 1967, Bedrock geology of the Goshen-Greenwood 

Lake area, New York: New York State Museum and Science 

Service Map and Chart Series 9, 78 p. 

Parris, D.C., and Cruikshank, K.M., in press, New biostratigraphic information on the Ordovician Martinsburg Formation of New Jersey and adjacent areas: New Jersey State 

Museum Investigation. 

Walker, R.G., and Mutti, Emiliano, 1973, Turbidite facies and 

facies associations, in Middleton, G. V., and Bouma, A.H., 

co-chairmen, Turbidites and deep-water sedimentation: Los 

Angeles, Society of Economic Paleontologists and Mineralogists, Pacific Section, p. 118-157. 

The High Point Member of the Martinsburg Formation in Northern New jersey and Southeastern New York 89 

Chapter C 

The Mount Eve Granite (Middle Proterozoic) 

of Northern New jersey and Southeastern 

New York 

By AVERY ALA DRAKE, jR., and JOHN N. ALEINIKOFF, 

U.S. Geological Survey, and RICHARD A. VOLKERT, 

New jersey Geological Survey 

Prepared in cooperation with the 

New jersey Geological Survey 

U.S. GEOLGICAL SURVEY BULLETIN 1952 

CONTRIBUTIONS TO NEW JERSEY GEOLOGY 

CONTENTS 

Abstract Cl 

Introduction Cl 

Regional Geology Cl 

Mount Eve Granite C3 

Petrography and Field Relations C3 

Chemistry C5 

U-Pb Geochronology C6 

Conclusions C7 

References Cited ClO 

FIGURES 

C 1, C2. Maps showing: 

C 1. Distribution of rocks older than 1 billion years in Eastern North 

America C2 

C2. Distribution of Middle Proterozoic rocks of the Reading Prong in 

northernmost New Jersey and immediately adjacent New 

York C3 

C3, C4. Generalized geologic maps of: 

C3. Parts of the Pine Island (New York-New Jersey), Unionville 

(New York-New Jersey), and Hamburg (New Jersey) 7.5-minute 

quadrangles showing distribution of the Mount Eve Granite C4 

C4. Southeast comer of the Newton East 7. 5-minute quadrangle showing location of an undeformed granitoid that may correlate with 

the Mount Eve Granite C5 

C5. Quartz-alkali feldspar-plagioclase plot of Mount Eve Granite C6 

C6-C9. Photographs showing: 

C6. Typical texture of Mount Eve Granite C6 

C7. Mount Eve Granite intruding amphibolite C6 

C8. Lenticular inclusion of potassic feldspar gneiss in Mount Eve 

Granite C7 

C9. Inclusions of amphibolite in Mount Eve Granite showing a slight 

preferred orientation C7 

C10. Normative feldspar plot of Mount Eve Granite CS 

C 11. Concordia diagram for zircons from the Mount Eve Granite C9 

TABLES 

C 1. Chemical analyses and CIPW norms of Mount Eve Granite CS 

C2. Uranium-lead concentration and isotopic composition data from zircon from the 

Mount Eve Granite C9 

Contents Ill 

The Mount Eve Granite (Middle Proterozoic) of 

Northern New jersey and Southeastern New York 

By Avery Ala Drake, Jr., John N. Aleinikoff, and Richard A. Volkert 

Abstract 

The Mount Eve Granite forms small intrusive bodies 

in a limited area of northern New jersey and adjacent New 

York. Most of the rock is syenogranite, and the unit is 

interpreted to be a Caledonian 1-type granite. The Mount 

Eve cuts across the structures in the metamorphic country 

rocks, and is itself undeformed. U-Pb data from abraded 

zircons plotted on a concordia diagram give an age of 

1 ,020±4 Ma, which is interpreted to be the crystallization 

age of the Mount Eve Granite. The lower intercept 

(280±190 Ma) suggests lead loss related to the Alleghanian 

orogeny, but the large uncertainty permits disturbance of 

the zircons during any event during the Phanerozoic. The 

Mount ~v~ is a p.ostkinematic intrusion emplaced during 

postcoll1s1on uplift. It, therefore, gives an upper bound 

for Grenvillian orogenesis in the Reading Prong. U-Pb 

systematics of unabraded zircons suggest an episode of 

lead loss coincident with the Avalonian event in southeastern New England and adjacent New York. 

INTRODUCTION 

Three suites of granitoid intrusive rocks occur in the 

New Jersey Highlands segment of the Reading Prong (figs. 

C 1, C2). The bulk of these rocks belong to the synkinematic 

Byram (Drake, 1984) and Lake Hopatcong (Drake and 

Volkert, chap. A, this vol.) Intrusive Suites, which form 

small to large, essentially conformable sheets within hornblende granulite facies country rocks that range from about 

200ft (feet) to as much as 4 mi (miles) long. The granitoid 

herein called Mount Eve Granite, on the other hand, forms 

small stocks that have dikelike and sill-like apophyses. The 

Mount Eve is restricted to the Pine Island, Unionville, 

Wawayanda, and Hamburg 7.5-minute quadrangles of New 

York and New Jersey (fig. C2). A small body of granitoid 

in the Newton East quadrangle (fig. C2) resembles the 

Mount Eve but differs from it in both petrography and 

chemistry. The purposes of this paper are to describe the 

Mount Eve Granite and to discuss its importance in deciphering the Grenvillian history of the Reading Prong. 

Manuscript approved for publication July 19, 1990. 

REGIONAL GEOLOGY 

The Losee Metamorphic Suite appears to constitute 

the oldest sequence of Middle Proterozoic rocks in the New 

Jersey Highlands. Parts of the Losee are well layered and 

foliated; other parts are poorly foliated granofels, and still 

others are granitoid or pegmatitic. Parts of the Losae 

contain fairly abundant amphibolite. The Losee rocks are 

very soda rich and have been interpreted to be metamorphosed quartz keratophyre and perhaps some trondhjemite 

intrusions (Drake, 1984). 

Closely associated with the Losee are chamockitic 

rocks. Some of these rocks have conspicuous alternating 

light and dark layers and have been interpreted to result 

from the high-grade metamorphism and anatexis of 

amphibolite-rich parts of the Losee Metamorphic Suite 

(Drake, 1984). A perplexing problem of these rocks is the 

general sparsity of orthopyroxene. Many rocks that have all 

the other attributes of charnockite lack hypersthene. Other 

chamockitic rocks are massive and have igneous textures. 

These rocks are interpreted to be enderbites. It appears that 

the chamockitic suite in the New Jersey Highlands includes 

both metamorphosed volcanic rocks and intrusions. 

The Losee and chamockitic rocks are unconformably 

overlain by a sequence of calcareous and quartzofeldspathic 

metasedimentary rocks. Calcareous rocks in the area of this 

report include marble and pyroxene (diopside) gneiss (fig. 

C3). The marble has traditionally been called Franklin 

Limestone (Spencer and others, 1908). Hague and others 

( 1956) found that the marble in its type area, the Franklin 

7.5-minute quadrangle (fig. C2), occurs in two major layers 

separated by a unit of potassic feldspar gneiss. They termed 

these layers the Franklin and Wildcat bands of marble and 

mapped them into the Pine Island quadrangle (fig. C2), 

where they are covered by lower Paleozoic sedimentary 

rocks. Detailed geologic mapping in connection with the 

new geologic map of New Jersey (R.A. Volkert and A.A. 

Drake, Jr., unpub. data) confirms the work of Hague and 

others (1956), and the Franklin Limestone is here redefined 

as Franklin Marble and revised to include only the Franklin 

band of marble. The Wildcat band of marble is herein 

formally named the Wildcat Marble. The lithic designation 

The Mount Eve Granite (Middle Proterozoic) of Northern New Jersey and Southeastern New York C1 
N 

EXPLANATION 

L........J 

~ 

Grenville Province 

Outliers of rocks 

(older than 1 billion years) 

0 200 MILES I I I I ! 

0 300 KILOMETERS 

Figure C1. Distribution of rocks older than 1 billion years in Eastern North America. 

LR, Long Range; C, Chain Lakes massif; G, Green Mountain massif; A, Adirondack 

massif; B, Berkshire massif; R, Reading Prong; H, Honey Brook upland; AW, 

Avondale-West Chester massif; BD, Baltimore "gneiss domes"; SM, Shenandoah 

massif; S, Sauratown Mountains window; FBM, French Broad massif; SA, Salem 

Church anticline; and P, Pine Mountain window. Modified from Drake (1984). 

"marble" is preferred to "Limestone" because the rock is 

marble. 

Pyroxene gneiss is highly variable in composition and 

may contain as much as 90 percent diopside or as much as 

80 percent plagioclase. That on Pochuck Mountain (fig. C3) 

is quite salic and contains layers of quartzite. 

Quartzofeldspathic gneiss includes a highly heterogeneous unit of biotite-quartz-feldspar gneiss and potassic 

C2 Contributions to New Jersey Geology 

feldspar gneiss. The more aluminous parts of both units 

contain sillimanite. The potassic feldspar gneiss on Pochuck 

Mountain (fig. C3) is characterized by quartz-sillimanite 

lenses as long as 3 in (inches). The biotite-quartz-feldspar 

gneiss is interpreted to be a metamorphosed graywackelike 

sand (Drake, 1984). Much of the potassic feldspar gneiss is 

interpreted to be a meta-arkose; other parts, however, are 

magnetite rich and resemble metamorphosed iron forma-
y 

41 °00' '---'--------'------'------'--"-----------' 

74°45' 

0 

I 

0 10 

10 

I 

I 

20 

I 

20 MILES 

I 

30 KILOMETERS 

Figure C2. Distribution of Middle Proterozoic rocks, Y, of 

the Reading Prong in northernmost New Jersey and immediately adjacent New York; £,Cambrian rocks; S£, Cambrian, Ordovician, Silurian rocks; OS, Silurian and Devonian rocks. Quadrangles (7.5-minute) are as follows: PJS, 

Port Jervis South; U, Unionville; PI, Pine Island; B, 

Branchville; HA, Hamburg; WA, Wawayanda; NE, Newton 

East; FR, Franklin; and N, Newfoundland. 

tion. Some workers (Grauch and Ludwig, 1980) have 

interpreted the potassic feldspar gneiss to be metamorphosed rhyolite, but many layers of the rock approach 

quartzite in composition, and a volcanic origin does not 

seem likely. The rocks, however, have magnetite-uraniumrare earth deposits that have a high barium content and, 

therefore, may well contain an exhalitive component. 

Amphibolite occurs with all the other rock units. 

Much is probably metasedimentary, as it occurs in uniform 

layers with the metasedimentary rocks. Small enclaves 

within other amphibolite bodies have coarsely crystalline 

igneous textures, so are probably metagabbro. Still other 

bodies, such as that on the south border of figure C3, 

contain relict pillow structures (Hague and others, 1956; 

Volkert and Drake, 1986) and are probably metavolcanic. 

Three phases of folds have been mapped in the New 

Jersey Highlands (Drake and others, 1985). These folds 

deform compositional layering and foliation marked by 

hornblende and feldspar crystals as well as lens-shaped 

lithologic units that probably resulted from regional transposition. None of the three mapped phases are first folds. 

The only evidence for earlier deformation is provided by the 

foliation and the regional transposition. The rocks of the 

Byram and Lake Hopatcong Intrusive Suites were emplaced 

synkinematically during the event, resulting in the oldest 

mapped folds. 

MOUNT EVE GRANITE 

The Mount Eve Granite is herein named for Mount 

Eve, Orange County, N.Y., in the Pine Island 7.5-minute 

quadrangle (figs. C2, C3), which is designated the type 

area. It also crops out on Mount Adam and in bodies both 

northeast and southwest of the type area. Intrusive bodies 

are abundant on Pochuck Mountain, and small bodies 

intrude the Franklin Marble near Amity (fig. C3). The 

granite was first recognized by Mather (1843), was later 

described by Kemp and Hollick (1894), and was mapped by 

Ries (1895). The name was first used by Hague and others 

( 1956), although there is no evidence that they meant to 

formalize it. Offield (1967) mapped and described the 

granite, but did not use the name Mount Eve. The name 

Mount Eve Granite as used by Hague and others ( 1956) is 

here accepted for use by the U.S. Geological Survey. 

Hague and others (1956) mapped a small granite body 

to the southeast of Lake Mohawk in the Newton East 

7 .5-minute quadrangle (figs. C2, C4). This granite is not 

deformed and physically resembles the Mount Eve, but it 

differs from the Mount Eve considerably, both petrographically and chemically (see below). 

The Mount Eve intrudes all the other map units in the 

Pine Island, Unionville, Wawayanda, and Hamburg quadrangles (fig. C3). The body in the Newton East quadrangle 

intrudes strongly foliated and lineated hornblende granite of 

the Byram Intrusive Suite. 

Petrography and Field Relations 

The Mount Eve Granite is a coarse- to mediumgrained, light-gray rock containing microcline or microcline 

microperthite, quartz, oligoclase, hornblende, and biotite. 

Allanite is a common accessory mineral, as is magnetite. 

Most of the rock is syenogranite, reflecting the high content 

of potassic feldspar (fig. C5). The one specimen from the 

Newton East quadrangle is, however, granodiorite. 

The Mount Eve Granite is undeformed (fig. C6), but 

at many places near contacts it has both a flow foliation and 

lineation. The fabric contains no evidence of either strain or 

recrystallization. There is abundant evidence at both map 

The Mount Eve Granite (Middle Proterozoic) of Northern New Jersey and Southeastern New York C3 

----- -------
Cambrian rocks 

UNCONFORMITY 

Mount Eve Granite 

INTRUSIVE CONTACTS 

Potassic feldspar gneiss 

Yb 

Biotite gneiss 

Amphibolite 

Pyroxene 

-

gneiss 

tY~w] 

Wildcat Marble 

I Y~f I 

Franklin Marble 

UNCONFORMITY 

IL-\\Ir- '11 

Losee Metamorphic Suite 

EXPLANATION 

Relative ages 

not known 

u 

D 

~ 

A 

B 

Contact 

High angle fault-U, upthrown side; 

0 , downthrown side 

Quarry 

Location of dated sample and 

chemical analysis 1 

Location of chemical analysis 2 

+ 

+ 

+ 

0 

I I 

0 2 

I 

2 MILES 

I 

3 KILOMETERS 

Figure C3. Generalized geologic map of parts of the Pine Island (New York-New Jersey), Unionville (New York-New 

Jersey), and Hamburg (New Jersey), Wawayanda (New Jersey-New York), 7.5-minute quadrangles showing distribution 

of the Mount Eve Granite. Geology of the Unionville quadrangle and the New Jersey part of the Pine Island quadrangles 

by A.A. Drake, Jr. (unpub. data). Geology of the Wawayanda and Hamburg quadrangles by R.A. Volkert (unpub. data). 

Geology of the New York part of the Pine Island quadrangle modified from Offield (1967). 

C4 Contributions to New jersey Geology 
EXPLANATION 

Cambrian rocks 

UNCONFORMITY 

&fQ~] Mount Eve Granite(?) 

INTRUSIVE CONTACTS 

Ybh 

Byram Intrusive Suite 

Ybh , hornblende 

granite 

Lake Hopatcong Intrusive Suite 

Ylhg , pyroxene granite; 

Ylhs, pyroxene syenite 

A 

INTRUSIVE CONTACTS 

!k~ } Potassic feldspar gneiss 

Amphibolite 

UNCONFORMITY 

~~~ vL ~I Losee Metamorphic Suite 

Contact 

Relative ages 

not known 

High angle fault-Dashed where concealed 

Thrust fault-Teeth on upper plate 

Location of chemical analysis 3 

0 

I I 

0 1 KILOMETER 

1 MILE 

I 

74° 

37' 

30" 

Figure C4. Generalized geologic map of the southeast corner of the Newton East 7.5-minute quadrangle showing location 

of an undeformed granitoid that may correlate with the Mount Eve Granite. Geology modified from Hague and others 

(1956). 

(fig. C3) and outcrop scales (figs. C7, C8) that the granite 

cuts across the layering, foliation, and folds in the metamorphic rocks. The Mount Eve contains abundant inclusions of the country rocks (figs. C7-C9). 

There is no evidence of either chilling against or 

reaction with the country rocks other than marble, although 

fairly abundant allanite-bearing pegmatites suggest that the 

magma was fairly fluid, as shown by contact aureoles in 

marble that are rich in choncrodite, scapolite, and other 

hydrous phases. 

Contact relations of the granitoid in the Newton East 

quadrangle could not be determined, but the body of 

potassic feldspar gneiss shown within the granite was 

probably engulfed. The granite does not have the strong 

penetrative fabric of the surrounding hornblende granite. 

Chemistry 

The limited amount of chemical data pertaining to the 

Mount Eve Granite are presented in table C 1 and classified 

in figure C 10. The sample from the Mount Eve quarry is a 

metaluminous granite, whereas the sample from Pochuck 

Mountain is corundum normative and is a peraluminous 

granite. Analyses of many more data will be needed to 

properly classify the Mount Eve Granite. 

Chemistry strongly suggests that the undeformed 

granite in the Newton East quadrangle is not Mount Eve 

Granite, and unless further chemical work shows a bimodal 

distribution of each type, the rocks are probably not 

petrogenetically related. 

The Mount Eve Granite (Middle Proterozoic) of Northern New Jersey and Southeastern New York C5 
Q 

Figure C5. Quartz-alkali feldspar-plagioclase plot (Streckeisen, 1976) of 12 samples of Mount Eve Granite. 

U-Pb Geochronology 

Zircons were separated from about 11.5 lb (pounds) 

of granite collected from a small, abandoned quarry on the 

east side of Mt. Adam (locality A in fig. C3). Most of the 

zircons are light to medium brown; some are gemlike and 

nearly clear. Length-to-width ratios range from 1 to 7, and 

lighter grains tend to be more acicular and doubly terminated. All grains have an adamantine luster. The smooth 

A 

Figure C6. Typical texture of Mount Eve Granite in quarry 

in the saddle between Mounts Adam and Eve (loc. A in fig. 

C3). Coin is 0.75 inch in diameter. 

faces and sharp interfacial angles on all grains indicate that 

these crystals have not been damaged or deformed. 

Seven size fractions of zircon were analyzed 

for uranium and lead concentrations and lead isotopiccompositions (table C2). In all cases, only the least magnetic, 

light-brown to clear zircons from each size fraction were 

analyzed. Zircons from the three coarse fractions, two of 

which were composed of handpicked, clear, elongate 

grains, were abraded to remove weak or damaged areas. 

B 

Figure C7. Mount Eve Granite intruding amphibolite in quarry in saddle between Mounts Adam and Eve. A, More distant 

view. Coin is 0.75 inch in diameter. 8, Close up. Granite cuts across the foliation in the amphibolite at a 90° angle. Coin 

is 0.75 inch in diameter. 

C6 Contributions to New Jersey Geology 
Figure C8. Lenticular inclusion of potassic feldspar gneiss 

in Mount Eve Granite in quarry in saddle between Mounts 

Adam and Eve (loc. A in fig. C3). Coin is 0.75 inch in 

diameter. 

Chemical methods for elemental extractions were modified 

from Krogh (1973). All isotopic ratios were measured on an 

automated, single collector, VG MicroMass 54E mass 

spectrometer, with Daly multiplier. Laboratory blank lead 

ranged from about 0.2 to 1 ng (nanogram), depending on 

sample size. Ages and concordia systematics were calculated using programs of Ludwig ( 1980, 1988). 

Uranium concentrations are relatively low, ranging 

from about 170 to 275 ppm (parts per million). The seven 

analyzed fractions form a linear array that is slightly 

discordant on a concordia plot (fig. C11), with an upper 

intercept age of 1034 ± 13 Ma and a lower intercept age of 

671 ± 110 Ma. However, because overgrowths are observed 

on many of the zircons, we also calculated a best-fit line 

through only the abraded fractions whose zircons should not 

contain any younger rims. This regression has intercept 

ages of 1020±4 and 280± 190 Ma. We interpret these 

results to indicate that the Mount Eve Granite crystallized at 

Figure C9. Inclusions of amphibolite in Mount Eve Granite 

in quarry in saddle between Mounts Adam and Eve (loc. A 

in fig. C4). Inclusions have a slight preferred orientation, 

probably resulting from flow alignment. Coin is 0.75 inch 

in diameter. 

about 1020 Ma. The lower intercept age is suggestive of 

Alleghanian disturbance and lead loss, but the uncertainty is 

large enough to include most possible events during the 

Phanerozoic. 

Fine, unabraded fractions are more discordant than 

the fractions composed of cores, and they plot to the left of 

the discordia shown in figure C11, suggesting formation of 

overgrowths probably during the Late Proterozoic (A valonian?). Modern lead loss slightly rotated the discordia for 

the composite grains, resulting in an upper intercept age that 

is somewhat too old. 

CONClUSIONS 

Igneous rocks in the New Jersey Highlands can be 

characterized as being prekinematic, synkinematic, and 

postkinematic as they relate to the Grenvillian orogenic 

event. The Losee Metamorphic Suite and the charnockitic 

The Mount Eve Granite (Middle Proterozoic) of Northern New Jersey and Southeastern New York C7 
Table C1. Chemical analyses and CIPW norms of Mount 

Eve Granite 1 

[In weight percent. Dashes indicate not present.] 

2 3 

Chemical analyses 

Si02 66.9 71.4 73.1 

Al20 3 13.9 14.3 14.6 

Fe20 3 1.6 1.71 1.4 

FeO 3.0 .88 .4 

MgO .74 .31 .16 

CaO 2.4 .77 1.5 

NazO 3.4 3.19 4.8 

K20 5.3 5.8 3.0 

H20+ .56 .53 .46 

H2o- .15 .12 .05 

Ti02 .74 .32 .11 

P20s .18 .05 .03 

MnO .10 .02 .02 

C02 .02 .01 .01 

Total 98.99 99.41 99.64 

CIPW norms 

Quartz 20.9 29.0 31.1 

Orthoclase 31.7 35.0 17.8 

Albite 29.3 27.2 40.4 

Anorthite 7.2 3.1 7.5 

Corundum 1.6 .8 

Diopside 3.3 .8 .4 

Hypersthene 3.3 

Magnetite 2.3 2.1 1.2 

Ilmenite 1.5 .6 .2 

Apatite . 3 .3 

Hematite .3 .6 

Total 99.8 100.0 100.0 

1

Descriptions and locations of rocks are as follows: 

1. Mt. Eve Granite from abandoned quarry in saddle between Mounts 

Adam and Eve 200 feet north of the intersection of Little Y ark and Hedges 

Roads, Pine Island 7.5-rninute quadrangle, N.Y.-N.J. (lac. A in fig. C3). 

Chemically, the rock is granite. This is the same locality as the dated 

sample. Rapid rock analysis by M. Kavulak, U.S. Geological Survey. 

2. Mt. Eve Granite from outcrop on northwest slope of Pochuck 

Mountain about 200 feet northeast of intersection of Liberty Comers Road 

and an unnamed northwest-trending road about 1 mile southwest of 

Owens, Unionville 7.5-minute quadrangle, N.Y.-N.J. (lac. Bin fig. C3). 

Chemically, the rock is granite. Rapid rock analysis by J. Taggart, A. 

Bartel, and D. Siems, U.S. Geological Survey. 

3. Granitoid from outcrop at sharp bend in unnumbered road about 1.4 

miles S. 5° W. from Sparta, N.J., Newton East 7.5-minute quadrangle, 

N.J. (lac. A in fig. C4). Chemically, the rock is trondhjemite. Rapid rock 

analysis by H. Smith, U.S. Geological Survey. 

sequence constitute the prekinematic sequence. They have 

been interpreted, on the basis of map relations, to be 

unconformably beneath the calcareous and quartzofeldspathic sequences. Recently, an unconformable contact 

between charnockite and an overlying feldspathic quartzite 

layer in potassic feldspar gneiss has been found, confirming 

C8 Contributions to New Jersey Geology 

An 

Figure Cl 0. Normative feldspar plot (O'Connor, 1965) of 

Mount Eve Granite. Sample 1 is from the Mount Eve 

quarry, sample 2 is from Pochuck Mountain, and sample 3 

is from south of Sparta, N.j. (loc. A in fig. C4). 

the earlier interpretation. These rocks have not yet been 

dated. 

The synkinematic rocks include the Byram and Lake 

Hopatcong Intrusive Suites, which were emplaced during 

the major episode of orogenesis. The Byram has an upper 

intercept U-Pb age of about 1090 Ma (Drake and others, 

chap. D, this vol.) . 

Evidence presented herein shows that the Mount Eve 

Granite is not deformed, and thereby is a posttectonic 

intrusion. It seems to have the general characteristics of 

Pitcher's (1982) Caledonian I-type granite, although we 

noted only metasedimentary xenoliths. This type of granite 

characteristically is emplaced during postcollision uplift. 

The Mount Eve Granite is postkinematic, and we place an 

upper bound for Grenvillian orogenesis in this part of the 

Reading Prong at 1020±4 Ma. 

The lower intercept age (fig. Cll) is 671 ± 110 Ma, 

suggesting an episode of lead loss corresponding to the time 

of the Avalonian event in eastern Connecticut and Rhode 

Island, where plagioclase gneisses and granites have been 

dated at about 620-600 Ma (Wintsch and Aleinikoff, 1987; 

Zartman and others, 1988). Farther west, in southern New 

York, using the Rb-Sr whole-rock method, Long (1969) 

determined an age of 563 ± 30 Ma for the Yonkers Gneiss 

(age recalculated using 87 = 1.42 x 10- 11 yr - 1

) and Mose 

and Hayes (1975) dated the Pound Ridge Gneiss at 583± 19 

Ma. A similar U-Pb lower intercept age has been found for 

the Storm King Granite (Aleinikoff, unpub. results, 1986). 

Thus, although evidence for an Avalonian disturbance is not 

pervasive throughout the Reading Prong and Hudson Highlands, some isotopic results suggest its occurrence in the 

area. 
Table C2. Uranium-lead concentration and isotopic compositien data from zircon from the Mount Eve Granite 

[mg, milligram; ppm, parts per million;] 

Weight Concentration 

(mg) (ppm) Pb composition2 Ratios3 Ages (Ma)4 

Fraction 1 

u Pb 206pb zo&Pb 206pb 206pb zo?Pb 207pb zo&pb 207pb 207pb 

204pb zo?Pb zoaPb 238u z3su zo&Pb 23au z3su 206pb 

( + 100)NMDEA 0.27 172.4 28.40 114320 13.660 15.601 .1684(.48) 1.696(.49) .0731(.08) 1003 1007 1016 

(-100+ 150)NMDEA 0.84 168.9 28.05 11107 13.436 16.423 .1698(.47) 1. 713(.47) .0731(.06) 1011 1013 1018 

(-150+200)NMD 6.64 238.6 39.35 2514.4 12.722 16.978 .1674(.55) 1.683(.56) .0729(.06) 998 1002 1012 

(-150+200)NMDA 0.58 266.8 42.98 9450.2 13.414 23.653 .1675(.46) 1.687(.47) .0730(.06) 998 1004 1015 

(-200+250)NMD 2.02 264.0 42.33 12684 13.527 21.768 .1663(.47) 1.670(.48) .0728(.11) 992 997 1008 

(-325+400)NMD 3.05 274.7 43.79 15862 13.596 20.980 .1652(.47) 1.655(.47) .0727(.06) 985 991 1004 

(-400)NMD 1.26 266.5 42.88 4225.7 13.180 17.698 .1645(. 79) 1.645(.80) .0725(.10) 982 987 1000 

1 Abbreviations: NM, nonmagnetic; D, diamagnetic; E. elongate; A, abraded. 2 Pb composition ratios corrected from 0.14± .05 %/average mass unit mass fractionation and 1 nanogram or less blank Pb of composition 

1:18.8:15.7:38.5. 3 2 sigma errors (expressed as a percent) in parentheses. 4 Ages corrected for common lead using appropriate values from Stacey and Kramers (1975). 

Constants: 235U=9.8485 E-10/yr; 238U= 1.55125 E-10/yr; 238UP35U= 137.88 (Steiger and, Jager 1977). 

0.176 

0.172 

:::::> 

~ 0.168 

-..0 

c... 

<0 

0 

N 

0.164 

0.160 

0.156 

1.54 1.58 1.62 1.66 

~ 

~ / 

~ / <::>/ 

/ 

/ 

Intercepts at 

/ 

/ 

/ 

/ 

/ 

1,019.8 ± 3.7 and 280 ± 190 million years 

( MSWD=0.0053) 

1.70 1.74 1.78 

2o1pb 1 23su 

1.82 

·figure C11. Concordia diagram for zircons from the Mount Eve Granite. MSWD, mean square 

of the weighted deviations (from the mean). 

The Mount Eve Granite (Middle Proterozoic) of Northern New Jersey and Southeastern New York C9 
REFERENCES CITED 

Drake, A.A., Jr., 1984, The Reading Prong of New Jersey and 

eastern Pennsylvania: An appraisal of rock relations and 

chemistry of a major Proterozoic terrane in the Appalachians, 

in Bartholomew, M.J., ed., The Grenville event in the 

Appalachians and related topics: Geological Society of America Special Paper 194, p. 75-109. 

Drake, A.A., Jr., Kastelic, R.L., Jr., and Lyttle, P.T., 1985, 

Geologic map of the eastern parts of the Belvidere and 

Portland quadrangles, Warren County, New Jersey: U.S. 

Geological Survey Miscellaneous Investigations Map 

I-1530, scale 1:24,000. 

Grauch, R.I., and Ludwig, K.R., 1980, Precambrian uranium 

mineralization in the central Appalachians: Geological Society of America Abstracts with Programs, v. 12, p. 39. 

Hague, J.M., Baum, J.L., Herrman, L.A., and Pickering, R.J., 

1956, Geology and structure of the Franklin-Sterling area, 

New Jersey: Geological Society of America Bulletin, v. 67, 

p. 434-474. 

Kemp, J.F., and Hollick, Arthur, 1894, The granite at Mounts 

Adam and Eve, Warwick, Orange County, N.Y., and its 

contact phenomena: New York Academy of Science Annals, 

V. 7, p. 638-654. 

Krogh, T .E., 1973, A low-contamination method for hydrothermal decomposition of zircon and extraction of U and Pb for 

isotopic age determination: Geochimica et Cosmochimica 

Acta, v. 37, p. 485-494. 

Long, L.E., 1969, Whole-rock Rb-Sr age of the Yonkers Gneiss, 

Manhattan Prong: Geological Society of America Bulletin, v. 

80, p. 2087-2090. 

Ludwig, K.R., 1980, Calculation of uncertainties ofU-Pb isotopic 

data: Earth and Planetary Science Letters, v. 46, p. 212-220. 

---1988, ISOPLOT VERSION 2-A plotting and regression 

program for isotope geochemists, for use with HP Series 

200/300 computers: U.S. Geological Survey Open-File 

Report 87-601, 59 p. 

Mather, W.W., 1843, Geology of New York, Part 1, Comprising 

the geology of the first geological district: Albany, New York 

Geological Survey, 653 p. 

Cl 0 Contributions to New Jersey Geology 

Mose, D.G., and Hayes, John, 1975, Avalonian igneous activity 

in the Manhattan Prong, southeastern New York: Geological 

Society of America Bulletin, v. 86, p. 929-932. 

O'Connor, J.T., 1965, A classification for quartz-rich igneous 

rocks based on feldspar ratios: U.S. Geological Survey 

Professional Paper 525-B, p. B79-B84. 

Offield, T.W., 1967, Bedrock geology of the Goshen-Greenwood 

Lake area, New York: New York State Museum and Science 

Service Map and Chart Series 9, 78 p. 

Pitcher, W.S., 1982, Granite type and tectonic environment, in 

Hsu, K.J., ed., Mountain building processes: New York, 

Academic Press, p. 19-40. 

Ries, Heinrich, 1895, Geology of Orange County: New York State 

Museum Annual Report 49, pt. 2, p. 393-475. 

Spencer, A.C., Kummel, H.B., Wolff, J.E., Salisbury, R.D., and 

Palache, Charles, 1908, Franklin Furnace, New Jersey: U.S. 

Geological Survey Geologic Atlas of the United States, Folio 

161, 27 p., 6 maps. 

Stacey, J. S., and Kramers, J.D., 1975, Approximation of terrestrial lead isotope evolution by a two-stage model: Earth and 

Planetary Science Letters, v. 26, p. 207-226. 

Steiger, R.H., and Jager, Emile, 1977, Subcommission on 

geochronology, Convention on the use of decay constants in 

geo- and cosmochronology: Earth and Planetary Science 

Letters, v. 36, p. 359-362. 

Streckeisen, Albert, 1976, To each plutonic rock its proper name: 

Earth Science Reviews, v. 12, p. 1-33. 

Volkert, R.A., and Drake, A.A., Jr., 1986, Some Middle Proterozoic rocks of the New Jersey Highlands, in Husch, J.M., 

and Goldstein, F.R., eds., Geology of the New Jersey 

Highlands and radon in New Jersey: Geological Association 

of New Jersey annual meeting, 3d, Randolph, N.J., Field 

guide and proceedings, p. 1-17. 

Wintsch, R.P., and Aleinikoff, J.N., 1987, U-Pb isotopic and 

geologic evidence for late Paleozoic anatexis, deformation, 

and accretion of the Late Proterozoic Avalon terrane, southcentral Connecticut: American Journal of Science, v. 287, 

p. 107-126. 

Zartman, R.H., Hermes, O.D., and Pease, M.H., Jr., 1988, 

Zircon crystallization ages, and subsequent isotopic disturbance events, in gneissic rocks of eastern Connecticut and 

western Rhode Island: American Journal of Science, v. 288, 

p. 376-402. 
Chapter D 

The Byram Intrusive Suite of the Reading ProngAge and Tectonic Environment 

By AVERY ALA DRAKE, JR., and JOHN N. ALEINIKOFF, U.S. 

Geological Survey, and RICHARD A. VOLKERT, New jersey 

Geological Survey 

Prepared in cooperation with the 

New jersey Geological Survey 

U.S. GEOLOGICAL SURVEY BULLETIN 1952 

CONTRIBUTIONS TO NEW JERSEY GEOLOGY 

CONTENTS 

Abstract Dl 

Introduction Dl 

Regional Geology Dl 

Byram Intrusive Suite D4 

Petrography and Field Relations D4 

Chemistry D4 

U-Pb Geochronology DS 

Storm King Granite D6 

Petrography and Field Relations D6 

Chemistry DlO 

Tectonic Environment Dll 

Conclusions Dll 

References Cited D13 

FIGURES 

D 1-D3. Maps showing: 

D 1. Distribution of rocks older than 1 billion years in Eastern North 

America D2 

D2. Highly generalized geologic map of the Durham and Reading 

Hills, New Jersey Highlands, and part of the Hudson 

Highlands D3 

D3. Distribution of Middle Proterozoic rocks of the Reading Prong in 

New Jersey and immediately adjacent New York DS 

D4. Modal Q-A-P plot of rocks of the Byram Intrusive Suite from the Durham 

and Reading Hills and the New Jersey Highlands D6 

D5. Geologic map of part of the Greenwood Lake quadrangle, New York-New 

Jersey D7 

D6. Modal Q-A-P plot of rocks of the Byram Intrusive Suite in the Greenwood 

Lake quadrangle, New York-New Jersey DS 

D7. Normative An-Ab-Or plot comparing rocks of the Byram Intrusive Suite with 

rocks of the Storm King Granite DS 

D8. Graph of Shand's index showing different tectonic environments of 

granitoids DS 

D9. Na20-K20 plot of rocks of the Byram Intrusive Suite and Storm King 

Granite D9 

D10. Graph of oxidation ratio vs. differentiation index of rocks of the Byram 

Intrusive Suite and Storm King Granite D9 

D11. Ti02-Fe0-Fe20 3 diagram for rocks of the Byram Intrusive Suite and Storm 

King Granite showing their oxidation state D9 

D12. Normative Q-Ab-Or plot of rocks of the Byram Intrusive Suite and Storm 

King Granite showing water pressures of 0.5, 2, and 5 kilobars D9 

D13. Plot of rocks of the Byram Intrusive Suite and Storm King Granite on the 

Or-Ab-An-Si02 system at 5 kilobars PH 0 DlO 

Dl4. Concordia plot of U-Pb data from zirco~s from sample NY/GL 1-82 DlO 

Contents Ill 
Contents IV 

D15. Generalized geologic map of the Bear Mountain area, New York D12 

D16. Modal Q-A-P plot of hornblende granite from the Hudson Highlands D13 

TABLES 

Dl. Molar Al20 3/(Ca0+ Na20+ K20) ratios of rocks of the Byram Intrusive Suite 

and Storm King Granite D8 

D2. U-Pb isotopic data from zircons from hornblende granite of the Byram Intrusive 

Suite Dll 
The Byram Intrusive Suite of the Reading ProngAge an~d Tectonic Environment 

By Avery Ala Drake, Jr., John N. Aleinikoff, and Richard A. Volkert 

Abstract 

Rocks of the Byram Intrusive Suite are the most 

abundant granitoid rocks in the Reading Prong of New 

Jersey and eastern Pennsylvania. The Storm King Granite 

in the Hudson Highlands to the east is similar to the Byram 

both petrographically and petrochemically, and the two 

units have been correlated by almost all geologists. Both 

units are 1-type granitoids, belong to the magnetite-series 

of granitoids, are interpreted to have been generated in a 

continental arc setting, and were synkinematically emplaced during the Grenville orogeny. 

Zircons from the Byram were difficult to date 

because of both an inherited component and later overgrowths. The time of emplacement of the Byram is best 

interpreted to be about 1090 Ma. The Storm King has a 

time of emplacement of about 1134 Ma. Taken at face 

value, this suggests that granite emplacement occurred 

over a period of about 44 m.y., not an unreasonable 

interpretation based on younger continental arc magma 

systems. In any case, the isotopic ages of these rocks 

suggest that the Grenville orogeny spanned the period 

1134 Ma to 1020 Ma, when the postkinematic Mount Eve 

Granite was emplaced. 

INTRODUCTION 

Granitoid rocks of the Byram Intrusive Suite are the 

most abundant intrusive rocks within the Durham and 

Reading Hills (Drake, in press a) and New Jersey Highlands 

(Drake, 1990) segments of the Reading Prong (fig. D1), a 

major external massif in the central Appalachians (Drake 

and others, 1988). Similar rocks crop out in the Hudson 

Highlands and were called Storm King Granite by Berkey 

(1907) and described in detail by Lowe (1950). Most 

geologists have correlated the Byram and Storm King 

because of their petrographic and chemical similarity. 

Recent U-Pb dating, however, suggests that the Storm King 

Granite has an age of about 1134 Ma (J.N. Aleinikoff, 

unpub. data) and the Byram an age of about 1090 Ma. In 

this paper we briefly discuss the petrography and petroManuscript approved for publication July 19, 1990. 

chemistry of the Byram Intrusive Suite and Storm King 

Granite, present the geochronological data for the Byram, 

interpret the tectonic environment within which the granitoids were emplaced, and attempt to explain the age 

dichotomy. 

REGIONAL GEOLOGY 

The Reading Prong is underlain by roughly equal 

parts of metavolcanic, metasedimentary, and granitoid 

intrusive rocks (fig. D2). The oldest of these rocks in 

Pennsylvania is the Hexenkopf Complex (Drake, 1984, in 

press a), a sequence of severely metamorphosed and altered 

mafic diorite, gabbro, pyroxenite, and impure chert that is 

interpreted to be an oceanic suite. The Hexenkopf Complex 

is unconformably overlain by the Losee Metamorphic Suite, 

a major rock unit in New Jersey and New York (fig. D2), 

where it is associated with rocks of charnockitic aspect. The 

Losee is interpreted to be a metamorphosed sequence of 

quartz keratophyre, dacite, and basalt, and related trondhjemite and tonalite intrusions (Drake, 1984, 1990, in press 

a). Many of the chamockitic rocks are interpreted to result 

from the high-grade metamorphism and anatexis of the 

Losee. Others are probably enderbite and quartz-poor 

enderbite intrusions (Drake, 1990). 

The Losee and chamockitic rocks are unconformably 

overlain by a sequence of marble, other calcareous rocks, 

and abundant quartzofeldspathic gneisses. Much of the 

quartzofeldspathic sequence is potassic feldspar gneiss that 

at places contains abundant magnetite, suggesting that it 

may be metamorphosed iron-formation, perhaps with an 

exhalitive component (Drake, 1984, 1990, in press a). 

All these rocks are intruded by large to small synkinematic sheets of the Byram Intrusive Suite (Drake, 1984), 

Storm King Granite (Lowe, 1950), and the Lake Hopatcong 

Intrusive Suite (Drake and Volkert, chap. A, this vol.). The 

Lake Hopatcong differs from the Byram and Storm King in 

that it is characterized by clinopyroxene and microantiperthite, whereas the other rocks are characterized by 

hornblende and microperthite. The Lake Hopatcong Intrusive Suite is not considered further herein. 

The Byram Intrusive Suite of the Reading Prong-Age and Textonic Environment 01 
N 

EXPLANATION 

Grenville Province 

Outliers of rocks 

(older than 1 billion years) 

0 200MILES I I I I I 

0 300 KILOMETERS 

Figure Dl. Distribution of rocks older than 1 billion years in Eastern North America. LR, 

Long Range; C, Chain Lakes massif; G, Green Mountain massif; A, Adirondack 

massif; B, Berkshire massif; R, Reading Prong; H, Honey Brook upland; AW, 

Avondale-West Chester massif; BD, Baltimore "gneiss domes"; SM, Shenandoah 

massif; S, Sauratown Mountains window; FBM, French Broad massif; SA, Salem 

Church anticline; and P, Pine Mountain window. Modified from Drake (1984). 

The metavolcanic and metasedimentary rocks are also 

intruded by small bodies of Mount Eve Granite in a small 

area of northern New Jersey and immediately adjacent New 

York (Drake and others, chap. C, this vol.). The Mount Eve 

appears to be postkinematic. It has an upper intercept U-Pb 

age of 1020±4 Ma, which can be taken as the upper bound 

for the Grenville orogeny in the New Jersey and Hudson 

Highlands (Drake and others, 1990, chap. C, this vol.). 

D2 Contributions to New Jersey Geology 

Three phases of folds have been mapped in the 

Durham and Reading Hills (Drake, in press b) and New 

Jersey Highlands (Drake and others, 1985). These folds 

deform compositional layering and foliation that is marked 

by hornblende and feldspar crystals, as well as lens-shaped 

rock bodies that probably result from regional transposition. 

None of these mapped phases are first folds. The only 

evidence for earlier deformation is provided by the foliation 
EXPlANATION 

Mesozoic rocks 

UNCONFORMITY 

Paleozoic rocks 

UNCONFORMITY 

[". - ,-- \-' 1 

t ~; :. ~ : : ~~~ :, ·: ~-

Granitoid rocks (Middle Proterozoic) 

INTRUSIVE CONTACTS 

Quartzofeldspathic rocks 

-

Marble 

(Middle Proterozoic) (Middle Proterozoic) 

UNCONFORMITY 

Losee Metamorphic Suite 

and charnockitic rocks 

(Middle Proterozoic) 

• • • 

K 

Contact 

Thrust fault-Sawteeth on upper plate 

High angle fault-Teeth on downthrown side 

Klippe 

0 

I 

0 

I 

20 MILES 

I 

20 KILOMETERS 

Figure D2. Highly generalized geologic map of the Durham and Reading Hills, New jersey Highlands, and part of the 

Hudson Highlands. Modified from Rankin, Drake, and Ratcliffe (1989). 

The Byram Intrusive Suite of the Reading Prong-Age and Textonic Environment 03 
and the regional transposition. The rocks of the Byram and 

Lake Hopatcong Intrusive Suites were emplaced synkinematically during the event, resulting in the oldest mapped 

folds. The Mount Eve Granite was emplaced after the 

youngest folds. 

Three fold phases are also recognized in the Hudson 

Highlands (Helenek, 1971; Dallmeyer, 1972; Ratcliffe and 

others, 1972; Helenek and Mose, 1984). The Storm King 

Granite was emplaced during the second of these phases 

(Ratcliffe, in Rankin and others, in press). The second 

mapped folds in the Hudson Highlands, therefore, correlate 

with the first mapped folds in the New Jersey Highlands and 

Durham and Reading Hills. 

BYRAM INTRUSIVE SUITE 

Rocks of the Byram Intrusive Suite are the most 

abundant of the Middle Proterozoic units in Pennsylvania 

(Drake, in press a) and western New Jersey. In central New 

Jersey, rocks of the Lake Hopatcong Intrusive Suite occur 

in subequal amounts with the Byram (Drake and Volkert, 

chap. A, this vol.). Many of the Lake Hopatcong rocks 

were mismapped as Byram by earlier workers. The Lake 

Hopatcong Intrusive Suite has not been recognized in 

southeastern New York. 

Petrography and Field Relations 

The Byram Intrusive Suite rocks are medium- to 

coarse-grained, pink to buff to bronze, gneissoid to indistinctly foliated granitoids and sparse granite gneiss. They 

consist largely of quartz, microperthite, and oligoclase. The 

Byram consists of five different rock types: hornblende 

granite, microperthite alaskite, hornblende-quartz syenite, 

hornblende syenite, and biotite granite. The hornblende 

granite differs from the alaskite in its content of hornblende 

(ferrohastingsite), and both differ from the syenites in their 

quartz contents. The quartz-poor rocks are most common in 

the Washington, Tranquility, and Stanhope quadrangles 

(fig. D3). Biotite granite occurs in sparse amounts and is 

interpreted to have resulted from the assimilation and 

modification of biotite-bearing metasedimentary rocks by 

alaskite (Drake, 1969, 1984; Sims, 1958). All phases of the 

Byram contain some magnetite, as much as 4 percent in 

some specimens, as well as accessory zircon, apatite, and 

sphene. 

Abundant modal data are available for rocks of the 

Byram Intrusive Suite in New Jersey west of the Franklin 

and Dover quadrangles (fig. D3) and in eastern Pennsylvania (fig. D4). The bulk of the rocks are either syenogranites 

or monzogranites that plot near the field boundary. Quartz 

syenite and syenite are underrepresented, because so few of 

these rocks have been point counted. Recent work north of 

the Wisconsinan terminal moraine, where more rocks are 

04 Contributions to New Jersey Geology 

exposed, shows that the interior parts of the intrusive sheets 

are alkali-feldspar granite, suggesting that these rocks may 

be a late differentiate. 

Migmatitic rocks have been recognized and described 

in western New Jersey and eastern Pennsylvania by Buckwalter (1962) and Drake and others (1961), but strangely 

have not been recognized east of the Belvidere quadrangle 

(fig. D3). Perhaps the migmatizing process has gone to 

completion in this area. 

To compare the rocks along the New Jersey-New 

York boundary with those from the better studied western 

area, modes of rocks from the Greenwood Lake quadrangle 

(figs. D3, D5) were plotted separately from those to the 

west (fig. D6). These modes have about the same distribution as those in figure D4, except that no syenites were 

recognized and there are proportionally fewer monzogranites and alkali feldspar granites. The dated sample ("x" in 

fig. D5) is an alkali feldspar granite containing about 57 

percent microperthite, 7 percent oligoclase, 31 percent 

quartz, and 5 percent hornblende. 

In most of New Jersey and eastern Pennsylvania, the 

Byram rocks form small to large, essentially conformable 

sheets within the hornblende granulite facies country rocks, 

which range from about 200 ft (feet) to as much as 4 mi 

(miles) long. The sheet from which the dated sample was 

taken in the Greenwood Lake quadrangle (fig. D5) appears 

to be more than 6 mi long, judging from the New York State 

map (Fisher and others, 1970). How much of this length is 

real and how much results from the requirements of 

small-scale compilation is unknown. In any case, the 

outcrop pattern and the bulbous southern end of the sheet 

east of Sterling Lake (fig. D5) suggest a refolded fold, and 

that the mapped synform is a third phase fold. 

Chemistry 

The chemistry of rocks from the Byram Intrusive 

Suite has been published by Baker and Buddington (1970), 

Drake (1969, 1984), Drake and Volkert (chap. A, this 

vol.), Sims (1958), and Young (1978). This chemistry is 

summarized in figure D7. Chemically, most of the rocks are 

granite and some are quartz monzonite. The aberrant 

trondhjemite and tonalite samples are hybrid rocks. The 

rocks are calc-alkaline (Drake, 1984; Drake and Volkert, 

chap. A, this vol.). Most are either mildly peraluminous or 

mildly metaluminous (fig. D8), but there is some scatter, 

probably because of the hybrid nature of some rocks. Their 

molecular ratios of Al20 3/(Ca0+ Na20+ K20) range from 

0.67 to 1.09, all being less than 1.1 (table D1). Their 

Na20/K20 ratios are greater than 1 (fig. D9), and their 

oxidation state is high (figs. D10, Dll). Almost all the 

rocks are diopside normative (Drake, 1984; Drake and 

Volkert, chap. A, this vol.). A Q-Ab-Or plot of the Byram 

rocks (fig. D12) shows that they tend to cluster at water 
0 

I 

0 

B 

E 

R 

I 

10 

10 

I 

I 

20 

I 

20 MILES 

I 

30 KILOMETERS 

N 

A 

NE 

U PI PLPK 

BM 

TH 

pp 

NEW JERSEY 

BV 

Figure 03. Distribution of Middle Proterozoic rocks of the Reading Prong in New Jersey and immediately adjacent New 

York. Quadrangles (7.5-minute) are as follows: R, Riegelsville; F, Frenchtown; FL, Flemington; E, Easton; BL, 

Bloomsbury; HB, High Bridge; CN, Califon; G, Gladstone; BV, Bernardsville; B, Banger; BE, Belvidere; W, Washington; 

H, Hackettstown; C, Chester; M, Mendham; MO, Morristown; BT, Blairstown; T, Tranquility; S, Stanhope; DO, Dover; 

BN, Boonton; PP, Pompton Plains; NE, Newton East; FR, Franklin; N, Newfoundland; WN, Wanaque; RM, Ramsey; HA, 

Hamburg; WA, Wawayanda; GL, Greenwood Lake; SL, Sloatsburg; TH, Thiels; U, Unionville; PI, Pine Island; WR, 

Warwick; MR, Monroe; PL, Popolopen Lake; and PK, Peekskill. Place mentioned in text: BM, Bear Mountain. 

pressures between 2 and 5 kb (kilobars). A normative 

An-Ab-Or plot (fig. D13) shows that most of the rocks plot 

in the low-temperature region of the system and near the 

orthoclase-oligoclase boundary of the granodiorite system 

(Tuttle and Bowen, 1958), suggesting that they solidified 

by fractional crystallization trending from granodioritic to 

alkali-feldspar granitic composition at temperatures roughly 

between 650 and 7 50 oc, assuming the system was water 

saturated. 

All these data suggest that rocks of the Byram 

Intrusive Suite are I-type granites that were derived from the 

melting of an igneous source (Chappell and White, 1974). 

In addition, most can be assigned to the magnetite series of 

Ishihara ( 1977). 

U-Pb Geochronology 

Zircons from hornblende granite sample NY /GL 1-82 

are heterogeneous in morphology. Nearly all the grains are 

fractured. Many are subhedral and nearly equant; about 10 

percent are euhedral, prismatic, and doubly terminated. 

Within the euhedral population, the grains are medium to 

dark brown, are finely zoned, and have thin, unzoned, clear 

overgrowths. About 20 percent of the euhedral zircons have 

an optically perceptible, rounded core (either clear or dark 

brown). Because of the variability in color, shape, zoning, 

and presence or absence of a core, we handpicked several 

fractions of zircons that appeared to be the least deformed 

(that is, had both terminations and minimal fractures), as 

The Byram Intrusive Suite of the Reading Prong-Age and Textonic Environment D5 
0 

Figure 04. Modal Q-A-P plot of rocks of the Byram Intrusive Suite from the Durham and Reading Hills and the New 

Jersey Highlands exclusive of the Greenwood Lake quadrangle. Data from Baker and Buddington (1970), Drake 

(1969), Hague and others (1956), Kastelic (1980), Sims 

(1958), Smith (1969), and Young (1971). 

well as three fractions separated by size and magnetic 

susceptibility. As discussed below, however, in spite of our 

attempts to prepare homogeneous splits, this granite has 

proved to be a formidable rock to date. 

Three fractions composed of diamagnetic and nonmagnetic zircons (table D2, fractions 6-8) have 207PbP06Pb 

ages ranging from 1031 to 1063 Ma. Five fractions composed of handpicked, nonmagnetic, abraded zircons have 

207PbP06Pb ages ranging from 1074 to 1110 Ma. Uranium 

concentrations range from 483 to 673 ppm in the unabraded 

splits and from 146 to 440 ppm in the abraded splits. As 

shown in figure D 14, the unabraded fractions are more 

discordant than the fractions of abraded zircon (except 

fraction 2). A best-fit regression through seven points 

(fraction 2 excluded) has an upper intercept age of 1122±53 

Ma and a large MSWD (mean square of the weighted 

deviations (from the mean)) (fig. D14). 

Based on morphology and isotopic systematics, we 

suggest that the unabraded zircons contain at least two age 

components: (1) the bulk of the crystals (euhedrally zoned) 

and (2) clear overgrowths. Grains with cores may have a 

third, inherited component. Fractions 6, 7, and 8 plot 

between these two age components (fig. D14). Four of the 

five abraded fractions (1, 3, 4, and 5) are between 2 and 4.5 . . 4 . h 2o7Pb/2o6Pb f percent d1scordant. Fract10n , w1t a age o 

1074 Ma, probably contained a small amount of rim 

material, despite abrasion. 207PbP06Pb ages of fractions 1, 

3, and 5 probably are representative of the age of intrusion 

of the granite. A best-fit line calculated for these three 

fractions and forced through a lower intercept of 0 ±50 Ma 

has an upper intercept age of 1088±41 Ma. The uncertainty 

06 Contributions to New Jersey Geology 

. . 2o7Pb/2o6Pb d is h1gh because of the 8-m.y. range m ages an 

the limited spread in Pb/U ages (table D2). Perhaps a better 

estimate of the age of emplacement, the weighted average 

of the 207PbP06Pb age of fractions 1, 3, and 5, is 1087±7 

Ma. The weighted average calculation assumes that the 

isotopic systematics of the cores were disturbed only in the 

geologic past. With a Paleozoic or Mesozoic Pb-loss event, 

the 207PbP06Pb ages become minimum ages. It is likely that 

the age of granite emplacement is about 1090 Ma. Thus, the 

upper intercept age based on the regression through seven 

fractions is spurious, the result of multiple times of zircon 

growth and lead loss. 

Fraction 2, with a 207PbP06Pb age of 1110 Ma, 

probably contained an inherited component. As noted 

earlier, about 20 percent of the prismatic grains contain 

cores. We suggest that despite our efforts to pick pristine, 

single-age-component grains, fraction 2 contained some 

grains with cores. 

The clear overgrowths probably formed after about 

1031 Ma e07PbP06Pb age of the ( -400)NM fraction (fraction 8, table D2)). A likely time of zircon overgrowth may 

be about 1020 Ma, the age of emplacement of the postkinematic Mount Eve Granite (Drake and others, chap. C, this 

vol.) of northern New Jersey and southeastern New York. 

Alternatively, the high-grade metamorphism responsible for 

regional foliation in the Byram Intrusive Suite, which 

occurred sometime between about 1090 and 1020 Ma 

(Drake and others, 1990), may have provided fluids and 

zircon for formation of the thin rims of zircon. 

STORM KING GRANITE 

Hornblende granite in the Hudson Highlands was 

named Storm King Granite by Berkey ( 1907) for exposures 

on Storm King Mountain in Putnam and Orange Counties, 

N.Y., and was mapped as such by Berkey and Rice (1919) 

and Lowe (1950). That name, however, was not used by 

Dodd (1965), who mapped in the same area (Popolopen 

Lake quadrangle, fig. D3) as Lowe, or by Jaffe and Jaffe 

(1973) in the Monroe quadrangle (fig. D3) immediately to 

the west. Storm King is not used on the Geologic Map of 

New York State (Fisher and others, 1970). More recent 

workers such as Helenek and Mose ( 1984) and Ratcliffe (in 

Rankin and others, in press) map the hornblende granite in 

the Hudson Highlands as Storm King Granite. It is considered herein that the hornblende granite in the Hudson 

Highlands is Storm King Granite. 

Petrography and Field Relations 

The typical Storm King Granite is medium to coarse 

grained, pink to buff to bronze, and gneissoid to nearly 
EXPLANATION 

Sedimentary rocks 

1.·. qd· :l Surficial deposits above Middle Proterozoic rocks 

(Quaternary) 

UNCONFORMITY 

Undifferentiated lower and middle Paleozoic rocks 

(Cambrian to Devonian) 

UNCONFORMITY 

Middle Proterozoic rocks 

Byram Intrusive Suite 

- Ybh 

Microperthite alaskite Hornblende granite 

INTRUSNE CONTACTS 

Metasedimentary and 

Metavolcanic rocks 

Potassic feldspar 

gneiss 

Amphibolite 

(some possibly 

intrusive) 

UNCONFORMITY 

Losee Metamorphic Suite 

~2~~~ ~;,~ 

Oligoclase 

quartz 

gneiss 

+ 

u 

X 

[~YJt:;~ [~~)P ·:j 

Oligoclase-quartz Plagioclasegneiss containing pyroxeneas much as 50 hornblende 

percent sadie gneiss of 

amphibolite charnockitic 

aspect 

Contact 

Thrust fault-Sawteeth on upper 

plate; dotted where concealed 

High angle fault-Relative 

movement shown where known 

Synform-Trough line and 

direction of plunge shown 

Overturned syncline-Trace 

of axial surface and direction of 

dip of limbs shown 

Magnetite mine 

Location of dated sample 

N 

A 

r---~~~~~~------~~~r.rr-~--~------r------------.~--~~r.-77;-~~F-~r--.410 

74° 

17' 

30" 

0 

0 2 

2 MILES 

3 KILOMETERS 

15' 

41° 

12' 

30" 

41° 

10' 

74° 

15' 

Figure 05. Geologic map of part of the Greenwood Lake quadrangle, New York-New Jersey, showing location of dated 

sample. Modified from Hotz (1953) and Offield (1967). 

The Byram Intrusive Suite of the Reading Prong-Age and Textonic Environment 07 
Q 

Figure 06. Modal Q-A-P (Streckeisen, 1976) plot of rocks of 

the Byram Intrusive Suite in the Greenwood Lake quadrangle, New York-New jersey. Dated sample, x. Data from 

Hotz (1953), Offield (1967), and this study. 

massive. It consists largely of quartz, microperthite, and 

oligoclase and as much as 13 percent hornblende (ferrohastingsite). The Storm King contains magnetite as well as 

minor amounts of apatite, zircon, sphene, tourmaline, and 

allanite. 

Dodd ( 1965) mapped leucogranite that appears to be 

similar to the microperthite alaskite of the Byram. He also 

described bitoite granite that grades down into hornblende 

An 

• Byram Intrusive Suite 

x Storm King Granite of 

Berkey (1907) 

Figure 07. Normative Ab-An-Or plot (O'Connor, 1965) 

comparing rocks of the Byram Intrusive Suite with rocks of 

the Storm King Granite of Berkey (1907). Byram data from 

Drake and Volkert (chap. A, this vol.). Storm King data 

from Lowe (1950). 

08 Contributions to New jersey Geology 

2.6 

.... 

ro 

0 E 2.2 

0 N 

~ 1.8 

+ 

~ ro 1.4 z 

...._ 

M 

0 N 

<( 

Metaluminous Peraluminous 

0.5 0.7 0.9 1.1 1.3 1.5 1.7 

Al 20 3 I (CaO + Na20 + K20) (molar) 

Figure 08. Shand's index showing different tectonic environments of granitoids (after Maniar and Piccoli, 1989). 

Fields are as follows: lAG, island arc granitoids; CAG, 

continental arc granitoids; CCG, continental collision 

granitoids; POG, postorogenic granites; RRG, rift-related 

granitoids; CEUG, continental epeirogenic uplift granitoids; and OP, oceanic plagiogranites. Data from Drake 

(1984), Drake and Volkert (chap. A, this vol.), and Lowe 

(1950). 

granite and upward into biotite-quartz-feldspar gneiss, suggesting that it is a hybrid rock like the biotite granite of the 

Byram Intrusive Suite. Dodd (1965) also mapped rocks that 

appear to be amphibolite migmatite (fig. D15) similar to 

those described by Buckwalter (1962) and Drake and others 

(1961) to the west. He (Dodd, 1965) suggested alternatively 

that these rocks may be restite from which melt has been 

extracted, rather than migmatite to which melt has been 

added. 

The Jaffes' description of hornblende granite in the 

Monroe quadrangle (fig. D3) is similar to that in the 

Popolopen Lake quadrangle. They also mapped small 

Table 01. Molar AI20 3/(CaO+Na20+K20) ratios of rocks 

of the Byram Intrusive Suite and Storm King Granite of 

Berkey (1907). 

[Data from Drake (1984), Drake and Volkert (chap. A, this vol.), and 

Lowe (1950)] 

Byram Intrusive Byram- Byram- Storm King 

Suite Cont. Cont. Granite 

0.99 1.01 0.84 1.02 

1.1 .99 .96 1.0 

1.09 .96 1.06 .77 

.98 .98 1.05 

.87 1.14 1.0 

1.04 1.07 1.01 

1.01 1.09 0.93 

1.06 1.04 1.05 

1.02 .67 
• • 5 

• 

- 4 • X c::: 

Q) • ~ ex • Q) • Q. • • • • • ..c 

- 3 ••• .t • C) • Byram Intrusive Suite 'Q) • ~ x Storm King Granite of • 

0 Berkey (1907) 

N 2 ctJ 

z 

• • • 

0~-L--~~---L--L--L--~~---L--L-~--J_~ 

0 2 3 4 5 6 

K20 (Weight percent) 

Figure 09. Na2 0-K2 0 plot of rocks of the Byram Intrusive 

Suite and Storm King Granite of Berkey (1907). 

bodies of microcline alaskite that resembles the alaskite of 

the Byram except in its alkali feldspar. They (Jaffe and 

Jaffe, 1973) also described, but did not map, biotite granite 

and migmatitic rocks. 

Modal data from the Popolopen Lake and Monroe 

quadrangles (fig. D3) are presented in figure D16. These 

data points have about the same distribution as those for 

0 

·~ 

80 

~ 60 

c::: 

0 

·~ 

C1l 

"0 

·x 

0 

40 

20 

• Byram Intrusive Suite 

X Storm King Granite of 

Berkey (1907) 

Mean= 38 

---

• 

• 

0 ~----~-----L----~------~-----L----~ 

40 50 60 70 80 90 100 

Differentiation index (Qtz +Or+ Ab) 

Figure 010. Oxidation ratio (2Fe20 3 X10 0/2Fe20 3 +F eO in 

mole percent (Chinner, 1960) vs. differentiation index 

(Thornton and Tuttle, 1960) of rocks of the Byram Intrusive 

Suite and Storm King Granite of Berkey (1907). Magnetite 

and ilmenite series fields from jin and others (1981). Data 

from Drake (1984), Drake and Volkert (chap. A, this vol.), 

and lowe (1950). 

• Byram Intrusive Suite 

x Storm King Granite of 

Berkey (1907) 

FeO L_____:IL._____J"-----___:,'--~'------'~~:..____;;t. __ __y_ __ _:u_ __ __::,[_ __ ~ Fe20 3 

Fe30 4 

Figure 011. Ti02-Fe0- Fe20 3 (mole percent) diagram for 

rocks of the Byram Intrusive Suite and Storm King Granite 

of Berkey (1907) showing their oxidation state. Magnetite 

and ilmenite series fields from Jin and others (1981). Data 

from Drake (1984), Drake and Volkert (chap. A, this vol.), 

and lowe (1950). 

areas to the west (figs. D4, D6). Here, as in northern New 

Jersey and Pennsylvania, alkali-feldspar granite appears to 

be restricted to the interior parts of the granitic bodies. 

The Storm King, like the Byram to the west, forms 

small to large, essentially conformable sheets within the 

hornblende granulite facies country rocks. The large Bear 

Mountain pluton (fig. D15) is a refolded sheet that is about 

5 mi long (Fisher and others, 1970) and about 1.25 mi wide. 

The largest sheet in the Monroe quadrangle (fig. D3) is 

0 

••• 

•• 

50 

• Byram Intrusive Suite 

X Storm King Granite of 

Berkey (1907) 

• 

Figure 012. Normative Q-Ab-Or plot of rocks of the Byram 

Intrusive Suite and Storm King Granite of Berkey (1907) 

showing water pressures of 0.5, 2, and 5 kilobars. 

The Byram Intrusive Suite of the Reading Prong-Age and Textonic Environment 09 
An 

• 

• Byram Intrusive Suite 

x Storm King Granite of 

Berkey (1907) 

Figure 013. Rocks of the Byram Intrusive Suite and Storm 

King Granite of Berkey (1907) plotted on the Si02 - saturated surface of the Or-Ab-An- Si02 system at 5 kilobars 

PH,a projected onto the Or- Ab-An face of the tetrahedron. Data from Drake (1969, 1984), Drake and Volkert 

(chap. A, this vol.), Lowe (1950), Sims (1958), and Young 

(1978). 

0.18 

::::> 0.17 co 

(") 

N 

-..0 

a.. 

<0 

0 

N 

0.16 

0.15 

0.14 

1.3 1.5 

about 6 mi long and about 0.5 mi wide (Jaffe and Jaffe, 

1973). Even larger sheets are shown by Fisher and others 

(1970), but this probably reflects the small-scale compilation, as the sheets mapped by Dodd (1965) and Jaffe and 

Jaffe (1973) are much smaller. 

Chemistry 

The only chemical data for the Storm King Granite 

that are available to us are the three analyses of Lowe 

(1950). These rocks are calc-alkaline (fig. D7). Two are 

slightly peraluminous, and a sample from the interior of the 

Bear Mountain pluton is metaluminous (fig. D8). The 

molecular ratios of Al20 3/(Ca0+ Na20+ K20) of Storm 

King samples are 1.02 or less (table D1). Their Na20/K20 

ratios are greater than 1 (fig. D9), and their oxidation state 

is high (figs. D10, D11). They are diopside normative 

(Lowe, 1950), and they plot at water pressures between 2 

and 5 kb on theQ-Ab-Or diagram (fig. D12). They lie in the 

low-temperature trough on the An-Ab-Or plot (fig. D13), 

suggesting that they, like the Byram, solidified from magmatic fractional crystallization trending from granodioritic 

to alkali-feldspar granitic composition at temperatures of 

650-750 °C. 

Intercepts at 

1,088 ± 41 and 0 ±50 million years 

(MSWD=56) 

Intercepts at 

1,122 ±53 and 660 ± 200 million years 

(MSWD=92) 

1.7 1.9 

2o1pb 1 23su 

2.1 

Figure 014. Concordia plot of U-Pb data from zircon from sample NY/GL 1-82. Diamonds are 

unabraded fractions (fractions 6-8, table D2); open circles are abraded fractions (fractions 

1-5, table D2); filled circles are used for regression forced through 0±50 Ma. MSWD, mean 

square of the weighted deviations (from the mean). See text for additional explanation. 

01 0 Contributions to New Jersey Geology 
Table 02. U-Pb isotopic data from zircons from hornblende granite of the Byram Intrusive Suite 

[mg, milligrams; ppm, parts per million] 

Concentration Pb composition2 Ratios (percent error)3 Ages (Ma)4 

Fraction 1 Weight (ppm) 2o&Pb 206pb 2o&Pb 2o&Pb 2o7Pb 2o7Pb 206pb 2o7Pb 207pb (mg) 

u Pb 2o4Pb 207pb 208pb 23su 23su 2o&Pb 23su 23su 206pb 

1 (-100+ 150)DA 1.01 370.2 65.13 17523 13.038 12.472 0.1767(.13) 1.849(.14) 0.0759(.06) 1049 1063 1092 

2 (-150+200)DA I .22 345.1 52.69 4670.4 12.561 10.149 .1501(.16) 1.585(.25) .0766(.19) 902 964 1110 

3 (-150+200)DA II .30 439.9 79.26 8961.2 12.943 12.077 .1803(.18) 1.881(.19) .0757(.06) 1068 1074 1086 

4 (-150+200)DA III .60 431.4 77.51 2354.9 12.307 11.054 .1770(.16) 1.835(.18) .0752(.08) 1050 1058 1074 

5 (-200+250)DA .30 145.8 25.61 13905 13.051 12.058 .1759(.18) 1.833(.26) .0756(.17) 1045 1058 1084 

6 (-100+ 150)D 1.22 506.3 84.77 215370 13.372 15.162 .1707(.21) 1.759(.22) .0747(.07) 1016 1030 1061 

7 (-150+200)D .26 483.1 80.56 44461 13.315 14.983 .1698(.18) 1.751(.19) .0748(.19) 1011 1027 1063 

8 (-400)NM 1.11 673.2 108.3 10893 13.345 15.100 .1637(.14) 1.662(.16) .0736(.06) 977 994 1031 

1 Abbreviations: D. diamagnetic; A, abraded; NM, nonmagnetic. 2 Blank and fractionation corrected. Blank lead composition is 1:18.7:15.6:37.2. 

3 2 sigma errors (expressed as percent) in parentheses. 4 Ages corrected for common lead using appropriate values from Stacey and Kramers (1975). 

Constants: 235U=9.8485 E-10/yr; 238U=1.55125 E-10/yr; 238U/235U=137.88 (Steiger and Jager, 1977). 

Available chemical data are similar to those of the 

Byram, as are other, more abundant Storm King data 

presented in Rankin and others (in press). The Storm King 

Granite, then, is anI-type granite derived from the melting 

of an igneous source (Chappell and White, 1974). 

TECTONIC ENVIRONMENT 

Maniar and Piccoli ( 1989) have recently developed 

criteria to determine the tectonic environment in which a 

granitoid was generated. The most critical factors for rocks 

like the Byram Intrusive Suite and Storm King Granite are 

their position on the Shand's index plot (fig. D8) and their 

molar ratios of Al20i(Ca0+ Na20+ K20). It can be seen 

that the bulk of the Byram and Storm King analyses plot 

within the continental arc granite field (fig. D8). There is an 

overlap between this field and that of continental collision 

granitoids, but rocks of these two environments can be 

separated on the basis of their molar ratios of 

Al20 3/(Ca0+ Na20+ K20) (Maniar and Piccoli, 1989). 

Continental arc granites have ratios less than 1.05, whereas 

continental collision granites have ratios greater than 1.15. 

It is not possible to discriminate between the environments 

that have ratios between 1.05 and 1.15. Most of the Byram 

and Storm King samples have ratios less than 1.05, and 

their highest ratio is 1.1 (table D1). It is concluded, 

therefore, that the Byram Intrusive Suite and Storm King 

Granite were generated in a continental arc setting. This 

conclusion is supported by their I-type nature and their 

assignment to the magnetite-series, which shows that they 

crystallized from highly oxidized magmas (Ishihara, 1977; 

Wones, 1981). Such magmas must come from an oxidized 

source, and a carbon-free ocean floor is a prime candidate 

for such a source. Such rocks must have been generated at 

an ocean-continental convergent margin along which a 

continental arc developed above a downgoing oceanic slab. 

It is difficult to determine at this time where the ocean was 

during Grenville time, but it was probably east of the 

Reading Prong (present direction), as granitoids similar to 

the Byram and Storm King occur in the external basement 

massifs and Adirondack Highlands to the north (Drake, 

1984; Drake and Ratcliffe, in Rankin and others, in press; 

Drake and Volkert, chap. A, this vol.). Such rocks are not 

known in the Honey Brook Uplands or internal basement 

massifs to the south (Crawford and Hoersch, 1984; Drake, 

1984; Drake and Ratcliffe, in Rankin and others, in press). 

Metamorphosed volcanic rocks, however, are abundant in 

the internal basement massifs that project to the east of the 

Reading Prong. 

CONCLUSIONS 

Rocks of the Byram Intrusive Suite and the Storm 

King Granite are quite similar in appearance, petrography, 

chemistry, and mode of emplacement. They differ in age, 

however, by 44 m. y. Taking the geochronologic data at 

face value suggests that granite emplacement occurred over 

this time span. Younger granitoids in continental arc settings such as the coastal batholith of Peru (Pitcher, 1978) 

and the Sierra Nevada batholith of California (Bateman and 

Clark, 1974) were emplaced over periods of 70 m.y. and 

60-80 m.y. respectively; therefore a period of intrusion of 

44 m.y. is not unreasonable. Some support for this concept 

is found in the work of Buddington and Leonard (1953), 

who found that the quartz- and potash-rich (alkali-feldspar 

granite) phases of the hornblende granite in the Adirondacks 

The Byram Intrusive Suite of the Reading Prong-Age and Textonic Environment 011 
EXPlANATION 

Quaternary deposits 

UNCONFORMITY 

Middle Proterozoic rocks 

Storm King Granite 

of Berkey (1907) 

INTRUSIVE CONTACTS 

Biotite-quartz-feldspar gneiss 

Biotite-hornblende-quartz feldspar gneiss, 

probably migmatized amphibolite 

Amphibolite and pyroxene amphibolite 

Garnet-pyroxene 

-

gneiss 

UNCONFORMITY 

Hypersthene-quartz-oligoclase 

gneiss (chamockite) 

Note: Pre-Storm King Granite rocks not 

separated east of 7 4 o longitude 

Contact 

u 

D High angle fault-U, upthrown side; 

D, downthrown side 

0 

I 

0 

Overturned synform-Direction 

of dip of limbs and plunge shown 

I 

1 MILE 

I 

1 KILOMETER 

74°00' 

,...,....,....-r~~....-:rrr-r-r----, 41 °22'30" 

N 

A 

Figure 015. Generalized geologic map of the Bear Mountain area, New York. Data from Dodd (1965) and 

Lowe (1950). 

012 Contributions to New Jersey Geology 
Q 

Figure 016. Modal Q-A-P (Streckeisen, 1976) plot of hornblende granite from the Hudson Highlands. (Storm King 

Granite is usage of Berkey, 1907.) Data from Dodd (1965): 

+,average of five samples from interior of West Mountain 

pluton of Storm King Granite, •, average of four samples 

from near contacts of West Mountain pluton of Storm 

King Granite; x, average of two samples from interior of 

Bear Mountain pluton of Storm King Granite; o, average 

of four samples from near contacts of Bear Mountain 

pluton of Storm King Granite; and o, other samples of 

hornblende granite from the Popolopen Lake quadrangle, 

New York. Data from Monroe quadrangle, New York, e, 

from Jaffe and Jaffe (1973). 

were younger differentiates of the same magma that produced the normal syeno- and monzogranites. The dated 

sample of Byram is an alkali-feldspar granite, whereas 

many of the other rocks are syeno- or monzogranites. On 

the other hand, zircons from the Storm King may, like the 

Byram, include an inherited element, and the rocks may 

actually be more similar in age. In any case, our current 

level of knowledge suggests that the Byram Intrusive Suite 

and Storm King Granite were generated in a continental arc 

setting, that magmatism extended from about 1134 Ma to 

1090 Ma, and that Grenville deformation extended from at 

least 1134 Ma to 1020 Ma, when the postkinematic Mount 

Eve Granite was intruded. 

REFERENCES CITED 

Baker, D.R., and Buddington, A.F., 1970, Geology and magnetite deposits of the Franklin quadrangle and part of the 

Hamburg quadrangle, New Jersey: U.S. Geological Survey 

Professional Paper 638, 73 p. 

Bateman, P.C., and Clark, L.D., 1974, Stratigraphic and structural setting of the Sierra Nevada batholith, California: 

Pacific Geology, v. 8, p. 79-89. 

Berkey, C.P., 1907, Structural and stratigraphic features of the 

basal gneisses of the Highlands: New York State Museum 

Bulletin 107, p. 361-387. 

Berkey, C.P., and Rice, Marion, 1919, Geology of the West Point 

quadrangle, New York: New York State Museum Bulletins 

225-226, 179 p. 

Buckwalter, T.V., 1962, The Precambrian geology of the Reading 

15-minute quadrangle: Pennsylvania Geological Survey, 4th 

ser., Progress Report 161, 49 p. 

Buddington, A.F., and Leonard, B.F., 1953, Chemical petrology 

and mineralogy of hornblendes in northwest Adirondack 

granitic rocks: American Mineralogist, v. 38, p. 891-902. 

Chappell, B.W., and White, A.J.R., 1974, Two contrasting 

granite types: Pacific Geology, v. 8, p. 173-174. 

Chinner, G.A., 1960, Pelitic gneisses with varying ferrous/ferric 

ratios from Glen Clova, Angus, Scotland: Journal of Petrology, v. 1, p. 178-217. 

Crawford, W.A., and Hoersch, A.L., 1984, The geology of the 

Honey Brook Upland, southeastern Pennsylvania, in Bartholomew, M.J., ed., The Grenville event in the Appalachians 

and related topics: Geological Society of America Special 

Paper 194, p. 111-125. 

Dallmeyer, R.D., 1972, Precambrian structural history of the 

Hudson Highlands, near Bear Mountain, New York: Geological Society of America Bulletin, v. 83, p. 895-904. 

Dodd, R.T., 1965, Precambrian geology of the Popolopen Lake 

quadrangle, southeastern New York: New York State 

Museum and Science Service Map and Chart Series 6, 39 p. 

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. 51-131. 

---1984, The Reading Prong of New Jersey and eastern 

Pennsylvania-An appraisal of rock relations and chemistry 

of a major Proterozoic terrane in the Appalachians, in 

Bartholomew, M.J., ed., The Grenville event in the Appalachians and related topics: Geological Society of America 

Special Paper 194, p. 7 5-109. 

---1990, The regional geologic setting of the FranklinSterling Hill district, Sussex County, New Jersey, in Character and Origin of the Franklin-Sterling Hill orebodies: 

Bethlehem, Pa., Franklin-Ogdensburg Mineralogical Society 

symposium, Lehigh University, Proceedings, p. 17-34. 

---in press a, Precambrian and lower Paleozoic metamorphic 

and igneous rocks of South Mountain and the Reading Prong, 

in Shultz, C. H., ed., The geology of Pennsylvania: Harrisburg, Pa., Pittsburgh Geological Society. 

---in press b, Structural geology and tectonics of South 

Mountain and the Reading Prong, in Shultz, C.H., ed., The 

geology of Pennsylvania: Harrisburg, Pa., Pittsburgh Geological Society. 

Drake, A.A., Jr., Aleinikoff, J.N., and Volkert, R.A., 1990, Synand post-kinematic granites of the New Jersey Highlands: 

Geological Society of America Abstracts with Programs, 

v. 22, p. 12. 

Drake, A.A., Jr., Hall, L.M., and Nelson, A.E., 1988, Basement 

and basement -cover relation map of the Appalachian orogen 

The Byram Intrusive Suite of the Reading Prong-Age and Textonic Environment 013 
in the United States: U.S. Geological Survey Miscellaneous 

Investigations Map I-1655, scale 1:1,000,000. 

Drake, A.A., Jr., Kastelic, R.L., Jr., and Lyttle, P.T., 1985, 

Geologic map of the eastern parts of the Belvidere and 

Portland quadrangles, Warren County, New Jersey: U.S. 

Geological Survey Miscellaneous Investigations Map 

I-1530, scale 1:24,000. 

Drake, A.A., Jr., McLaughlin, D.B., and Davis, R.E., 1961, 

Geology of the Frenchtown quadrangle, New JerseyPennsylvania: U.S. Geological Survey Geologic Quadrangle 

Map GQ-133, scale 1:24,000. 

Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 1970, Geologic map of New York State, Lower Hudson sheet: New 

York State Museum and Science Service Map and Chart 

Series 15, scale 1:250,000. 

Hague, J.M., Baum, J.L., Herrman, L.A., and Pickering, R.J., 

1956, Geology and structure of the Franklin-Sterling area, 

New Jersey: Geological Society of America Bulletin, v. 67, 

p. 434-474. 

Helenek, H.L., 1971, An investigation of the origin, structure, 

and metamorphic evolution of major rock units in the Hudson 

Highlands: Unpub. Ph.D. thesis, Brown University, 244 p. 

Helenek, H.L., and Mose, D.G., 1984, Geology and geochronology of Canada Hill Granite and its bearing on the timing of 

the Grenvillian events in the Hudson Highlands, New York, 

in Bartholomew, M.J., ed., The Grenville event in the 

Appalachians and related topics: Geological Society of America Special Paper 194, p. 57-73. 

Hotz, P.E., 1953, Magnetite deposits of the Sterling Lake, 

N.Y.-Ringwood, N.J., area: U.S. Geological Survey Bulletin 982-F, p. 153-244. 

Ishihara, S., 1977, The magnetite-series and ilmenite-series granitic rocks: Mining Geology, v. 27, p. 293-305. 

Jaffe, H.W., and Jaffe, E.B., 1973, Bedrock geology of the 

Monroe quadrangle, Orange County, New York: New York 

State Museum and Science Service Map and Chart Series 20, 

74 p. 

Jin, M-S, Kim, S-Y, and Lee, J-S, 1981, Granitic magmatism and 

associated mineralization in the Gyeongsand Basin, Korea: 

Mining Geology, v. 31, p. 245-260. 

Kastelic, R.L., Jr., 1980, Precambrian geology and magnetite 

deposits of the New Jersey Highlands in Warren County, 

New Jersey: U.S. Geological Survey Open-File Report 

80-789, 140 p. 

Lowe, K.E., 1950, Storm King Granite at Bear Mountain, N.Y.: 

Geological Society of America Bulletin, v. 61, p. 137-190. 

Maniar, P.D., and Piccoli, P.M., 1989, Tectonic discrimination 

of granitoids: Geological Society of America Bulletin, 

v. 101, p. 635-643. 

O'Connor, J.T., 1965, A classification for quartz-rich igneous 

rocks based on feldspar ratios: U.S. Geological Survey 

Professional Paper 525-B, p. B79-B84. 

Offield, T. W., 1967, Bedrock geology of the Goshen-Greenwood 

Lake area, New York: New York Museum and Science 

Service Map and Chart Series 9, 78 p. 

Pitcher, W.S., 1978, The anatomy of a batholith: Journal of the 

Geological Society of London, v. 135, p. 157-182. 

014 Contributions to New Jersey Geology 

Rankin, D.W., Drake, A.A., Jr., Glover, Lynn, III, Goldsmith, 

Richard, Hall, L.M., Murray, D.P., Ratcliffe, N.M., Read, 

J.F., Secor, D.T., Jr., and Stanley, R.S., 1989, Pre-orogenic 

terranes, in Hatcher, R.D., Jr., Thomas, W.A., and Viele, 

G.W., eds., The Appalachian-Ouachita Orogen, U.S. (The 

Geology of North America, v. F-2): Boulder, Colo., Geological Society of America, p. 7-100. 

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Geologic map of the U.S. Appalachians showing the Laurentian margin and Taconic orogen, in Hatcher, R.D., Jr., 

Thomas, W.A., and Viele, G.W., eds., The AppalachianOuachita Orogen, U.S. (The Geology of North America, 

v. F-2): Boulder, Colo., Geological Society of America, 

scale 1:1,500,000. 

---in press, Proterozoic North American (Laurentian) rocks of 

the Appalachian orogen, in Reed, J.C., Jr., Bickford, M.E., 

Houston, R.S., Link, P.K., Rankin, D.W., Sims, P.K., and 

Van Schmus, W.R., Precambrian: Conterminous U.S. (The 

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Ratcliffe, N.M., Armstrong, R.L., Chai, B.H.T., and Seneschel, 

R.G., 1972, K-Ar and Rb-Sr geochronology of the Canopus 

pluton, Hudson Highlands, New York: Geological Society of 

America Bulletin, v. 83, p. 523-530. 

Sims, P.K., 1958, Geology and magnetite deposits of the Dover 

district, Morris County, New Jersey: U.S. Geological Survey 

Professional Paper 287, 162 p. 

Smith, B.L., 1969, The Precambrian geology of the central and 

northeastern parts of the New Jersey Highlands, 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. 35-47. 

Stacey, J. S. , and Kramers, J.D. , 197 5, Approximation of terrestrial lead isotope evolution by a two-stage model: Earth and 

Planetary Science Letters, v. 26, p. 207-226. 

Steiger, R.H., and Jager, Emile, 1977, Subcommission of 

geochronology, Convention on the use of decay constants in 

geo- and cosmochronology: Earth and Planetary Science 

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Streckeisen, Albert, 1976, To each plutonic rock its proper name: 

Earth Science Reviews, v. 12, p. 1-33. 

Thornton, C.P., and Tuttle, O.F., 1960, Chemistry of igneous 

rocks-I, Differentiation index: American Journal of Science, v. 258, p. 664-684. 

Tuttle, O.F., and Bowen, N.L., 1958, Origin of granite in the 

light of experimental studies in the system NaA1Si30 8-

KA1Si308-Si02-H20: Geological Society of America Memoir 74, 153 p. 

Wones, D. R. , 1981 , Mafic silicates as indicators of intensive 

variables in granitic magmas: Mining Geology, v. 31, 

p. 191-212. 

Young, D.A., 1971, Precambrian rocks of the Lake Hopatcong 

area, New Jersey: Geological Society of America Bulletin, 

v. 82, p. 143-158. 

---1978, Precambrian salic intrusive rocks of the Reading 

Prong: Geological Society of America Bulletin, v. 89, 

p. 1502-1514. 
SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS 

Periodicals 

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Professional Papers are mainly comprehensive scientific reports 

of wide and lasting interest and importance to professional scientists 

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and of topographic, hydrologic, and geologic investigations. They also 

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