Index of Granitic Rock Masses 

in the 

State of Nevada 

By FLORIAN MALDONADO, RICHARD W. SPENGLER, 

W.F. HANNA, and G.L. DIXON 

Prepared in cooperation with the 

U.S. Department of Energy 

A compilation of data on 205 areas of exposed 

granitic rock masses in Nevada 

U.S. GEOLOGICAL SURVEY BULLETIN 1831 
DEPARTMENT OF THE INTERIOR 

DONALD PAUL HODEL, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1988 

For sale by the 

Books and Open-File Reports Section 

U.S. Geological Survey 

Federal Center, Box 25425 

Denver, CO 80225 

Any use of trade names is for descriptive purposes only and does not imply 

endorsement by the U.S. Geological Survey. 

Library of Congress Cataloging-in-Publication Data 

Index of granitic rock masses in the state of Nevada. 

(U.S. Geological Survey bulletin ; 1831) 

Bibliography: p. 

Supt. of Docs. no.: I 19.3:1831 1. Granite-Nevada. 2. Intrusions 

(Geology) -Nevada. I. Maldonado, Florian. II. United States. Dept. of 

Energy. Ill. Series. 

QE75.89 no. 1831 557.3 s [552'.3] 88-600149 

[OE462.G7] 
CONTENTS 

Abstract 1 

Introduction 1 

Definitions of selected terms as used in this report 1 

Scope of study 2 

Clark County 9 

Geology 9 

Plutons 9 

Lincoln County 1S 

Geology 1S 

Plutons 1S 

Southern Nye County 17 

Geology 17 

Plutons 17 

Northern Nye County 20 

Geology 20 

Plutons 22 

Esmeralda County 25 

Geology 25 

Plutons 27 

Mineral County 31 

Geology 31 

Plutons 31 

Lyon County 35 

Geology 35 

Plutons 35 

Churchill County 38 

Geology 38 

Plutons 40 

Lander County 42 

Geology 42 

Plutons 44 

Eureka County 46 

Geology 46 

Plutons 48 

White Pine County 50 

Geology 50 

Plutons 50 

Elko County 55 

Geology 55 

Plutons 55 

Humboldt County 61 

Geology 61 

Plutons 61 

Pershing County 66 

Geology 66 

Plutons 68 

Washoe, Storey, and Douglas Counties and Carson City 72 

Contents Ill 
Geology 72 

Plutons 72 

Selected references 77 

PLATE 

[Plate is in pocket) 

1. Map showing aeromagnetic data and distribution of plutonic rocks in Nevada 

FIGURES 

1. Index map of Nevada showing locations of counties and the Nevada Test 

Site 2 

2. Diagram showing variation of amplitude of aeromagnetic anomaly with 

increasing thickness of prismatic source 11 

3. Diagram showing variation of shape and location of aeromagnetic anomaly 

with change in total magnetization direction of prismatic source 12 

4-18. Location of plutons in: 

TABLES 

4. Clark County 13 

5. Lincoln County 16 

6. Southern Nye County 18 

7. Northern Nye County 21 

8. Esmeralda County 26 

9. Mineral County 32 

10. Lyon County 36 

11. Churchill County 39 

12. Lander County 43 

13. Eureka County 47 

14. White Pine County 51 

15. Elko County 57 

16. Humboldt County 63 

17. Pershing County 67 

18. Washoe, Storey, and Douglas Counties and Carson City 

(independent city) 73 

1. Generalized classification of granitic rocks 2 

2. Summary of data related to plutons in the State of Nevada 4 

3. Major stratigraphic and geologic time divisions 10 

IV Contents 
Index of Granitic Rock Masses in the State of Nevada 

By Florian Maldonado, Richard W. Spengler, W.F. Hanna, and G.L. Dixon 

Abstract 

A compilation of 205 areas of exposed granitic rock in 

Nevada was undertaken for the U.S. Department of Energy. 

The purpose was to obtain data for evaluating granitic rock 

masses as potential underground nuclear waste repositories. 

Information, compiled by county for areas of granitic rock 

exposure, includes general location, coordinates, land 

classification, areal extent, accessibility, composition, age, 

rocks intruded, aeromagnetic expression, mining activity, 

and selected references. 

INTRODUCTION 

This index of exposed granitic masses within the 

State of Nevada summarizes geographic information, 

geologic and aeromagnetic data, mining activity, and 

selected references. The information was obtained 

primarily from published and unpublished reports and 

maps of the U.S. Geological Survey (USGS) and the 

Nevada Bureau of Mines and Geology and has been 

released as an open-file report (Spengler and others, 

1979). This report is a summary of that open-file report 

that included all of the above listed factors in addition to 

hydrologic setting. Several maps included in the open-file 

report are omitted in this report because of their large 

size: (1) topographic map of the State of Nevada, (2) 

generalized land classification of Nevada, (3) generalized 

hydrology of Nevada and other parts of the Great Basin, 

showing ground-water discharge and major sources of 

recharge and runoff, ( 4) tectonic map of Nevada 

and parts of California, (5) preliminary location of 

earthquake epicenters throughout Nevada and in parts 

of California, and ( 6) composite aeromagnetic map of 

Nevada. 

This index involved compilation of data from 

several earth-science disciplines. Geographic and 

geologic data for Clark, northern Nye, Mineral, Eureka, 

Churchill, Elko, Washoe, Storey, and Douglas Counties 

and Carson City were compiled by Richard W. Spengler. 

Florian Maldonado compiled geographic and geologic 

information for Lincoln, Esmeralda, Lyon, White 

Pine, Lander, Pershing, Humboldt, and southern Nye 

Counties. W.F. Hanna contributed sections on aeromagnetic data. 

Definitions of Selected Terms as 

Used in This Report 

Aeromagnetic anomalies.-These features are 

perturbations of the Earth's magnetic field that have 

been sensed by an aircraft-borne magnetometer and are 

displayed as oontours. Relative maximums and 

minimums of closed-contour anomalies are referred to, 

respectively, as highs and lows. 

The source of an anomaly refers to the magnetized 

rocks that cause the anomaly-the total magnetization 

(magnetic dipole moment per unit volume) of the rocks 

is attributable to magnetite or a related magnetic mineral 

species. In general, mafic rocks such as basalt or diorite 

have stronger magnetizations than felsic rocks such as 

rhyolite or granite, largely because of greater abundances 

of magnetic mineral grains but occasionally because of 

the small size of microscopic domains within the grains. 

The trend, gradient, and wavelength of an anomaly 

refer, respectively, to the azimuthal orientation of its axis, 

the amount of change in amplitude per unit of horizontal 

distance across the entire anomaly (mathematically, this 

is actually about one-half the full wavelength), and the 

distance between successive similar points across the 

crest of the anomaly, assuming that it extends 

horizontally as a continuous waveform. 

Granitic rock.-A holocrystalline, quartz-bearing, 

plutonic rock ranging in composition from granite to 

diorite (table 1 ). 

Pluton.-A single exposure or group of exposures 

of a body of igneous rock that has formed beneath the 

surface of the Earth by crystallization of magma. The 

term has been broadly used to conveniently group 

outcrops rather than to imply any genetic relationship. In 

certain cases, the terms "stock" and "batholith" have 

been substituted for pluton. Herein, stock refers to 

igneous intrusions that have less than 100 km2 of surface 

exposure, and may or may not imply a discordant 

relationship with the surrounding country rock. Batholith 

Introduction 
Table 1. Generalized classification of granitic rocks 

Potassium feldspar Potassium feldspar Plagioclase feldspar 

>%total 11:!-% total >% total feldspar 

feldspar feldspar Potassium feldspar Potassium feldspar 

Texture >10 percent < 10 percent Quartz Quartz Quartz Quartz total feldspar total feldspar >10 <10 >10 <10 Quartz Quartz Quartz 

percent percent percent percent >10 percent > 10 percent I < 10 percent 

Equigranular Granite Syenite Quartz 

monzonite 

Monzonite Granodiorite Quartz 

diorite 

Diorite 

Quartz Quartz Porphyritic Granite Syenite monzonite Monzonite Granodiorite diorite Diorite 

granular porphyry porphyry porphyry porphyry porphyry porphyry porphyry 

denotes a plutonic mass that has more than 100 km2 of 

surface area. 

Scope of Study 

Information on the following factors: general 

location, coordinates, land classification, area, 

accessibility, composition, age, rocks intruded, aeromagnetic expression, and mining activity for each pluton in 

Nevada was obtained from the literature. The index was 

then compiled by county (fig. 1 ), with two exceptions. 

Nye County was divided into two sections; Washoe, 

Storey, and Douglas Counties and Carson City were 

combined into one section. The information compiled is 

presented for each county and begins with an 

introduction that briefly describes the regional geologic 

setting and is followed by a county map that indicates the 

location and distribution of plutons within that county. 

Information on the above factors is then presented for 

each pluton and summarized in table 2 for all the plutons. 

The following is an explanation of the factors. 

Designation of p/utons.-Individual exposures or 

groups of exposures were assigned a name, prefiX, and 

number to facilitate reference to the State map (pl. 1 ), 

county maps, figures, and discussions. Names of plutons 

were taken from the literature, where available. Granitic 

rock exposures not previously named were assigned 

names of local mining districts or topographic features 

occurring on or near the plutons. The prefix signifies the 

county in which the pluton occurs and the number 

represents the order of discussion for each pluton within 

a particular county.~ The prefix designations for the 

counties are as follows: 

CL-Clark 

LI-Lincoln 

SN-Nye (southern part) 

NN-Nye (northern part) 

ES-Esmeralda 

M-Mineral 

L-Lyon 

CH-Churchill 

LA-Lander 

EU-Eureka 

WP-White Pine 

EL-Elko 

li-Humboldt 

P-Pershing 

WS-Washoe 

*-Carson City (independent city) 

S-Storcy 

D-Douglas 

*Outcrops occurring in Carson City (independent city) are included in 

Washoe and Douglas Counties. 

2 Index of Granitic Rock Masses in Nevada 

Genera/location.-A generalized location of each 

pluton is given, referenced to a particular topographic, or 

cultural feature (pl. 1 ). 

Coordinates.-Latitude and longitude of the 

approximate center of each pluton have been recorded in 

degrees and minutes. Measurements were made from 

maps of 1:500,000 or 1:250,000 scale. Where a pluton 

consists of a cluster of outcrops, the coordinates were 

measured from a central point within the largest outcrop, 

or from a point centrally located within the group. 

Figure 1. Index map of Nevada showing locations of 

counties and the Nevada Test Site (NTS). 
Land classification.-Classification of land refers 

to either private ownership or to the administration of 

lands under Federal jurisdiction. Information was 

obtained and, in some cases, generalized from Lutsey 

and Nichols (1972). 

Area.-Exposed areas of granitic rock were 

measured using a compensating polar planimeter and are 

expressed in square kilometers. Approximate surface 

configurations were obtained from the respective county 

geologic maps and the Nevada State geologic map 

(1:500,000) by Stewart and Carlson (1974, and 1978). 

Where a pluton is represented by several isolated 

exposures, the cumulative area of all exposures is 

recorded. 

Accessibility.-Data given in this section were 

interpreted principally from U.S. Army Map Senrice 

topographic sheets (1:250,000), USGS topographic map 

series, and USGS State of Nevada map (1965, 

1:500,000). Data provide approximate distances to 

improved roads such as major State, U.S., and Interstate 

Highways, and railroads. Unimproved roads commonly 

extend to the plutons, but are mentioned only if major 

roadways are not nearby. 

Composition.-The major composition of the pluton is given. Many of the granitic rock masses have been 

classified by field inspection only and their composition 

(or classification) has not been confirmed by geochemical or petrographic analysis. 

Age.-Radiometric age data are presented where 

available; they include the age, method used, material 

dated, and reference. Where radiometric age 

determinations are not available, the age is based on fiield 

relationships. In cases where age is uncertain, a hyphen 

has been inserted between the divisions of geologic time 

to indicate and (or). 

Rocks intruded.-Included in this section are 

formation name(s), age(s), and rock type(s). Where 

rocks intruded are not exposed, rocks that overlie the 

pluton are noted. 

Aeromagnetic expression.-Two aeromagnetic 

anomaly maps of Nevada have been used in this report: 

(1) a mosaic of many individual maps (Zietz and others, 

1977), corresponding to aeromagnetic surveys having 

highly diverse flight specifications; and (2) a map of 

analytically merged aeromagnetic data (Sweeney and 

others, 1978), simulating a single aeromagnetic survey 

made at high elevation. Most surveys represented on the 

mosaic map correspond to a flight elevation of about 2.7 

km; a few were made at elevations ranging from about 

0.15 km to 3.8 km. The analytically merged map 

simulates a flight elevation of 3.8 km. 

Aeromagnetic anomalies or parts of anomalies 

have been correlated with previously mapped igneous or 

metamorphic rocks. Qualitative, rather than quantitative, 

inferences have been made about anomaly sources, with 

most information provided in brief telegraphic style. 

Information on anomalies is based on state-wide data 

published by Spengler and others (1979); quantitative 

analysis of anomalies in Nevada is currently underway 

(Blakely, 1986), with emphasis on determining the 

depths to the bottom of magnetic rock sources, for use in 

determining Curie-temperature isotherms. 

The amplitudes or shapes of anomalies depend 

largely on the thickness of the source rocks-an 

expression of the volume of magnetic material-and on 

the magnitude and direction of total magnetization in the 

source rocks. The direction of total magnetization may 

depart significantly from the direction of the Earth's 

ambient magnetic field because of the presence of 

anomalously directed remanent magnetization, 

especially in some volcanic rocks. 

As a semiquantitative aid to the infrequent user of 

aeromagnetic-anomaly data, a few examples of 

anomalies expected to be caused by terranes of plutonic 

and other magnetic rocks in Nevada are shown in 

idealized form in figures 2 and 3. Figure 2 shows 

variations of anomaly amplitudes with increasing 

thickness of a typical prismatic source; figure 3 shows 

variations of anomaly shape and anomaly location with 

respect to a source with change in direction of total 

magnetization. The height of the magnetometer above 

the source rocks is assumed to be 1.5 km. This height is 

representative of those areas where the high-level data 

(Sweeney and others, 1978) were acquired over highly 

elevated sources of about 2.3 km elevation and 

representative of those areas where the lower-level data 

(Zietz and others, 1977) were acquired over sources that 

range from moderately elevated at a 1.7 km elevation to 

moderately buried at a depth of 1.4 km. The principal 

inferences to be drawn from figures 2 and 3 are that (1) 

high-amplitude anomalies must have sources that are 

thick and have strong total magnetization, and (2) such 

anomalies will approximately outline the tops of sources 

if the total magnetization is steeply inclined. Both of 

these conditions appear to apply widely in Nevada. 

Mining activity.-Data provided in this section 

denote areas near plutons where mining and drilling 

operations were in progress as late as 1976, and name the 

major commodities being developed. Comments 

regarding historical mining activities (1900--1976) have 

been made for selected plutons. Areas of local mining 

have been extracted from Payne and Papke (1977). 

Selected references.-The major sources of geologic 

information for most counties are listed within the 

introduction to each county. Published sources of 

information pertaining to age determination are given 

Introduction 3 
,. Table 2. Summary of data related to plutons in the State of Nevada 

3' 

Q. 

= 0 

-

Q 

.. 

! 

Ct. 

() 

:a 

0 

() 

~ 

~ (II 

: 

(II 

s· 

z 

! 

Q. 

I» 

Pluton 

designation 

by county 

Clark County 

CL·1 

CL-2 

CL-3 

CL-4 

CL-5 

Cl-6 

CL-7 

CL-8 

Lincoln County 

Ll-1 

Ll-2 

Ll-3 

Ll-4 

Ll-5 

Ll-6 

Southern Nye 

County 

SN-1 

SN-2 

SN-3 

SN-4 

SN-5 

SN-6 

SN-7 

SN-8 

Northern Nye 

County 

NN-1 

NN-2 

NN-3 

NN-4 

NN-5 

NN-6a 

NN-6b 

NN-7 

NN-8 

NN-9 

NN-1 Oa 

Composition 

Q) Q) ..... 

~ -~ "§ ~ ·c: :0 .... 0 

co CO N 0 

t5 a 5 c: 

~ E (9 

X X 

X 

X X 

X 

X X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X X 

X 

2X 

X 

X 

X 

X X 

X 

X X X 

X 

X X 

X 

X X 

X 

X 

Age 

c: II) 

co 0 (.) :J 

..... 

Q) 

~ ·c;; ·c;; 0 

Q) ~ 

"§ -~ E II) II) (.) 

co co co t 

i5 co ~ :; a> Q) (.) 

Q) -, ~ u ct 

X 

X X 

X 

X 

X X 

X X 

X 

X 

X X 

X 

X X 

X 

X 

X X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X X X 

X 

X 

X 

X 

X X X 

X X X 

X 

X X X 

Aeromagnetic Expression 

Radiometric Thrust Anomaly Pluton areal extent 5 0ther 

age 1Commodity fault 

determination mined in Weak Approximately Larger Mixed 

made vicinity High Low or equals than or 

none exposures exposures unknown 

X Ag,Au X X 

X X 

X X X 

X X X 

X Ag,Au X X 

Pb,Ag X X 

X X X 

X X 

X X X 

X w X X X 

X X X 

X X X X 

X X X 

X X 

X X 

X X 

X X 

X w X X X 

X X X 

X X 

X X 

X X 

X X X 

X X X X 

X X 

X X X 

X Au X X 

X Ag,Au X X 

Ag,Au X X X 

X X X 

X w X X 

X X 

Au X X X 
S' 

~ 

0 

Q. 

c 

~ 0 

:I 

en 

NN-10b 

NN-11 

NN-12a 

NN-12b 

NN-12c 

NN-13 

Esmeralda County 

ES-1 

ES-2 

ES-3 

ES-4 

ES-5 

ES-6 

ES-7 

ES-8 

ES-9 

ES-10 

ES-11 

ES-12 

ES-13 

ES-14 

ES-15 

ES-16 

Mineral County 

M-1 

M-2 

M-3 

M-4 

M-5 

M-6 

M-7 

M-8 

M-9 

M-10 

M-11 

Luning County 

L-1 

L-2 

L-3 

L-4 

L-5 

L-6 

L-7 

L-8 

L-9 

L-10 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X X X 

X X X 

X 

X X X 

X X X 

X X X 

X X X 

X X 

X X X 

X X 

X X 

X X X X 

X X X 

X X X 

X X 

X X X 

X X 

X X 

X X 

X X 

X X 

X X 

X X X X 

X X X 

X 

X 

X X X X 

X X X X 

X X X X 

X X 

X X X 

X X X 

X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X 

X X X X 

w X X X 

Li X X X 

X X 

X X X 

X Pb, Ag, Au X X X 

X Au, W X X X X 

Au,Ag X X 

X X X X 

X X X X 

X X X 

X X X 

X X X 

X X X X X 

X· X X 

X X X X 

X X 

X X X X 

X X X 

X I X X 

X Au,Ag X X X 

w X X 

X X 

X Au,Ag X X 

X X 

X X X 

X X X 

X X X X 

X w X X X 

X X 

X X I 

X X 

Au,Ag X X 

X X X X 

X X 

Cu X X 

X X 

X X 

X X 

X X I 

X X 

I 
en 

:; 

a. 

~ 

0 

-

C) 

a; 

:::s 

::+ 

c;· 

:a 

g 

~ 

3: 

I» 

., 

., 

CD 

., 

s· 

z 

! 

a. 

I» 

Table 2. Summary of data related to plutons in the State of Nevada-Continued 

Composition Age 

Pluton Q) Radiometric Q) .... 1:: Cll 

.... "§ ctl () () ::I age designation .!!:! N ·- t 1:: .!!:! ~ ·c;; ·c;; 0 

Q) ~ 

.!!:! determination by county ·c: ctl 0 -c "§ E Cll Cll () 

ctl ::I N 0 ctl e ctl t 

(5 0 § 1:: 0 ctl 

..:: ::I a) Q) made ctl () 

~ E Q) ...., (5 u It 

Churchill County 

CH-1 X X X X 

CH-2 X X X X 

CH-3 X X X 

CH-4 X X X X 

CH-5 X X X 

CH-6 X X X X 

CH-7 X X X X 

CH-8 X X X X 

CH-9 X X X X X 

CH-10 X X X X X 

CH-11 X X X X X 

CH-12 X X 

Lander County 

LA-1 X X X X 

LA-2 X X X 

LA-3 X X X X X X X 

LA-4 X X X X 

LA-5 X X X 

LA-6 X X X X X 

LA-7 X X X X 

LA-8 X X X X 

LA-9 X X X 

LA-1 0 X X X X X X 

Eureka County 

EU-1 a X X X X X 

EU-1 b X X X 

EU-2 X X X 

EU-3 X X X 

EU-4 X 3X X 

EU-5 X X X X X X 

EU-6 X X X 

EU-7 X X X 

EU-8 X X X 

EU-9 X X X X X 

White Pine County 

WP-1 X X X X 

WP-2 X X X X X X 

WP-3 X X X X X X 

WP-4 X X 

WP-5 X X 

Aeromagnetic Expression 

Thrust Anomaly Pluton areal extent 50ther 1Commodity fault 

mined in Weak Approximately Larger Mixed 

vicinity High Low or equals than or 

none exposures exposures unknown 

X X 

Au, Ag, W X X X 

X X 

Sb X X 

w X X 

X X 

Pb X X 

X X 

X X 

X X 

X X 

X X 

Au. Cu X X X I 

Au. Cu X X X 

X X 

Au X X X X 

X X 

X X X 

X X 

X X 

X X 

X X X 

Au,Ag X X X X 

Au,Ag X X X X 

X X 

Fe X X 

X X 

Au,Ag X X X 

X X X 

X X 

X X 

X X 

Au. W X X X 

X X X 

X X X 

X X X 

X X X X 
~ 0 

Q. 

c 

n 

ct. 

0 

::::. 

..., 

WP-6 

WP-7 

WP-8 

WP-9 

WP-10 

WP-11 

WP-12 

WP-13 

WP-14 

WP-15 

WP-16 

WP-17 

WP-18 

Elko County 

EL-1 

EL-2 

EL-3 

EL-4 

EL-5 

EL-6 

EL-7 

EL-8 

EL-9 

EL-1 0 

EL-11 

EL-12 

EL-13 

EL-14 

EL-15 

EL-16 

EL-17 

EL-18 

EL-19 

EL-20 

EL-21 

EL-22 

Humboldt County 

H-1 

H-2 

H-3 

H-4 

H-5 

H-6 

H-7 

H-8 

H-9 

H-10 

H-11 

X 

X 

X 

X 

X X 

X 

X 

X 

X 

X 

X X 

X 

X 

X 

X 

X 

X 

X 

2X X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X X 

X X X X 

X X 

X X 

X X 

X X 

X X 

X X X X 

XI X 

X ~IX X X X 

X 

X X X 

X X X 

X X X X 

X X X X 

X X X 

X X X X 

X 

X X X X 

X X X 

X 

X X 

X X 

X X 

X 

X X X X 

X X 

X X 

X X 

X X 

X X X 

X X 

X X 

X X X 

X Pb. Ag X X 

X Au. Ag,Cu X X X 

X X X 

X X X X 

X X X X 

X X 

X X 

X X X 

X X 

X 

X X 

X X X X 

X Ag X X X 

X Au. Ag, W X X 

X Au. Ag, W X X 

X X X 

X X X 

X X X 

X X 

X I I I I I X 

X X 

X X X 

X X X 

X Cu X X 

X X 

X X X 

X X 

X X X X 

X X 

X X X X 

X X 

X X X X 

X X X 

X X X 

X X 

X X X 

X X X 

X X X X 

X w X X X 

X X X X 

X X 

Au X X 

X X X 

X X X 

X X X -------- ------ --
CG 

:; 

a. 

~ 

0 

C) -

; 

~ 

r! 

(') 

:c 

g 

~ 

3: 

II) 

en 

en 

CD 

en 

:;· 

z 

CD 

~ a. 

• 

Table 2. Summary of data related to plutons in the State of Nevada-Continued 

Composition Age 

Pluton CJ.) c: Radiometric CJ.) (/) ..... (IJ ..... :::J "§ u u age designation ~ N ·- ..... c: ~ :§ ·c;; ·c;; 0 ~ ·c: .... 0 :.0 "§ (/) (/) CJ.) 

-~ determination by county E u (IJ CIJ N 0 (IJ (IJ (IJ t:: (5 a a c: i:5 (IJ ;!: .... 1i) CJ.) made u :::J 

E (IJ CJ.) J u r- (5 a': 

H-12 X X 

H-13 X X X 

H-14 X X X X 

H-15 X X X 

H-16 X X X 

H-17 X X X 

H-18 X X X 

H-19 X X X 

Pershing County 

P-1 X X X 

P-2 X X X 

P-3 X X 

P-4 X X 

P-5 X X X 

P-6 X X X 

P-7 X X X 

P-8 4X X 

P-9 X X X 

P-1 0 X X X 

P-11 X X X 

P-12 4X X 

P-13 4X X X X X 

P-14 4X X 

P-15 X X X X 

P-16 X X 

P-17 X X X X 

P-18 X X X 

Washoe County 

WS-1 X X X 

WS-2 X X 

WS-3 X X 

WS-4 X X 

WS-5 X X 

WS-6 X X X X 

WS-7 X X 

WS-8 X X X 

WS-9 X X X X 

Douglas County 

D-1 X X X X 

D-2 X X X 

D-3 X X X X 

Aeromagnetic Expression 

Thrust Anomaly Pluton areal extent 5 0ther 1Commodity fault 

mined in Weak Approximately Larger Mixed 

vicinity High Low or equals than or 

none exposures exposures unknown 

X X 

Au X X 

X X 

X X X 

X X X 

X X X 

X X 

X X X 

X X 

X X 

X X 

Au. Ag X X 

Au X X 

X X 

w X X 

Au X X X 

X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X 

X X 

X X 

X X 

X X 

X X 

X X 

X X 

X X 

X X 

X X 

X X 
X 

X 

X 

X 

::l 

<C 

X 

X 

X 

X 

X 

~ c 

::J 

0 

u 

~ ....... ('.1 

ochch 

ci5 

under "Age", and sources of geologic data are given 

under "Selected references" for each pluton discussed. 

Time did not permit an exhaustive study of all available 

literature; however, additional reports are cited in the list 

of selected references at the back of this index. 

CLARK COUNTY 

Geology 

Clark County is situated in the extreme southern 

tip of Nevada, bounded on the southeast by the Colorado 

River, which forms a natural boundary between Nevada 

and Arizona. The southwest edge of the county forms 

part of the Nevada-California State line (fig. 4). 

Plutons exposed within Clark County range in 

composition from granite to diorite and range in age 

from Precambrian to Tertiary. The intrusions are south 

and east of Las Vegas and extend southward to the 

southern tip of Nevada. Most of the igneous masses lie 

adjacent to either Lake Mead or the Colorado River. 

Eastern Clark County differs geologically from 

other Nevada counties by having extensive exposures of 

Precambrian rocks. These rocks consist mainly of schist, 

gneiss, and granite that crop out in the Virgin Mountains 

east of Las Vegas and west of the Colorado River. The 

Precambrian granites are generally coarse grained and 

brecciated, and commonly form networks of dikes and 

stringers that intricately penetrate the metamorphic 

rocks. 

Triassic and Tertiary granitic rocks form a northtrending complex that underlies the Eldorado and Newberry Mountains, directly south of Boulder City. The 

plutons are discontinuously enclosed by Precambrian 

gneisses, schists, and granites. These rocks not only 

exhibit a wide variation in mineralogical composition but 

also vary considerably in texture. At many localities, 

dikes of several compositions and textures, including 

aplites, pegmatites, and hornblendites, cut both the metamorphic and granitic rocks. 

Plutons 

CL-1. Gold Butte District 

General location: South end of the south Virgin 

Mountains, directly east of the mouth of the Overton Arm of Lake Mead. 

Coordinates: lat 36°12' N., long 114°11' W. 

Land classification: The southern half of the area lies 

within the Lake Mead recreation area, and the 

northern half is designated as public domain. 

Clark County 9 
Table 3. Major stratigraphic and geologic time divisions . Modified from "Major geochronologic and chronostratigraphic 

units,• Geologic Names Committee, 1983, U.S. Geological Survey 

Era or System or Period 

Erathem 

QUATERNARY 

CENOZOIC 

TERTIARY 

CRETACEOUS 

MESOZOIC 

JURASSIC 

TRIASSIC 

PERMIAN 

PENNSYLVANIAN 

MISSISSIPPIAN 

DEVONIAN 

PALEOZOIC 

SILURIAN 

ORDOVICIAN 

CAMBRIAN 

PRECAMBRIAN 

Area: 120 km2

• 

Accessibility: Jeep trails extending northward that cross 

the Colorado River approximately 51 km north of 

the exposures. 

Composition: Granite and quartz monzonite. 

10 Index of Granitic Rock Masses in Nevada 

Age estimates 

commonly used for 

Series or Epoch 

boundaries (in 

millions of years 

Holocene 

0.010 -

Pleistocene 

2 (1.7-2.2) - Pliocene 

Miocene 

5 (4.9-5.3)-

24 (23-26)-

Oligocene 38 (34-38) -

Eocene 

55 (54-56)-

Paleocene 

63 (63-66)-

Upper (Late) I- 96 (95-97)-

Lower( Early) 

138 (135-141)-

Upper (Late) 

Middle (Middle) 

Lower( Early) 

205 (200-215)-

Upper (Late) 

Middle (Middle) 

Lower( Early) 

-240 -

Upper (Late) 

Lower( Early) 

290 (290-305)-

Upper (Late) 

Middle (Middle) 

Lower( Early) 

~330 -

Upper (Late) 

Lower( Early) 

360 (360-365) -

Upper (Late) 

Middle (Middle) 

Lower( Early) 

410 (405-415) -

Upper (Late) 

Middle (Middle) 

Lower( Early) 

435 (435-440)-

Upper (Late) 

Middle (Middle) 

Lower( Early) 

500 (495-510) -

Upper (Lat~ 

Middle (Mi die) 

Lower( Early) 

~570 -

Age: 1.06 Ga, 1.09 Ga, Rb-Sr, potassium feldspar (Volborth, 1962) (Precambrian). 

Rocks intruded: Precambrian gneiss, migmatite, 

granite, pyroxenite, and hornblendite. 
.------o---------' 

20 

Thickness= 1 50 m Thickness= 375 m 

A B 

1 

MAGNETIC 

NORTH 

Thickness = 7 50 m 

c 

10 KILOMETI:RS 

Thickness = 1 ,500 m 

D 

Figure 2. Variation of amplitude of aeromagnetic anomaly with increasing thickness of prismatic 

source as indicated, A-D. Hei~ht of aircraft magnetometer above source is 1.5 km; total 

magnetization of source is 1 Am· , of same direction and polarity as Earth's ambient ma~netic field; 

contour interval is 20 gammas (nT); areal extent of source is slightly greater than 50 km . Note that 

anomalies, regardless of thickness, occur almost directly over tops of sources. 

Aeromagnetic expression: 

Anomaly: High (long-wavelength, high-amplitude). 

Inferred source: Same areal extent as exposed plutonic rocks. 

Remark: Northward displacement of anomaly is 

associated with topography. 

Mining activity: Gold and silver have been mined at two 

localities within the district. 

Selected reference: Volborth, 1962. 

CL-2. Wilson Ridge 

General location: Hamblin Mountains. 

Coordinates: lat 36°10' N., long 114°35' W. 

Land classification: Recreation area. 

Area: 33 km 2

• 

Accessibility: A secondary, all-weather road extends 

east of Las Vegas and flanks the northern edge of 

Lake Mead, approximately 2 km north of the 

exposure. 

Composition: Granite and diorite. 

Age: Tertiary. 

Rocks intruded: Precambrian gneiss, schist and 

pegmatite, and Gale Hills Formation 

(Cretaceous(?) and Tertiary-conglomerate, 

sandstone, and limestone). 

Aeromagnetic expression: 

Anomaly: High (northeast-trending). 

Inferred source: Basalt and related extrusive rocks. 

Mining activity: None. 

Selected reference: Anderson, 1973. 

Clark County 11 
Magnetization direction: D = 0°, 1=0° 

A 

0----

Magnetization direction: D = 90°E., 1=0° 

B 

MAGNETIC 

NORTH 

Magnetization direction: D = 90°E., 1=60° 

c 

Magnetization direction: Vertical 

D 

Figure 3. Variation of shape and location of aeromagnetic anomaly with change in total magnetization direction of prismatic 

source. (D = declination, .I = inclination). Height of aircraft magnetometer above source is 1.5 km; total magnetization of 

source is 1 A m"1

; thickness of source is 1.5 km; contour interval is 20 gammas (nT); areal extent of source is slightly greater 

than 50 km2

• Note that anomalies associated with sources having shallow magnetization inclinations (A and B) occur over 

opposite edges of source. Anomalies associated with sources having steep magnetization inclinations (C and D) occur almost 

directly over tops of sources. 

CL-3. Boulder City 

General location: Underlies Boulder City. 

Coordinates: lat 35°59' N., long 114°49' W. 

Land classification: Private land within the city limits of 

Boulder City. 

Area: 34 km 2

• 

Accessibility: U.S. Highway 93 crosses the exposure. 

Composition: Granite and granodiorite. 

Age: 53± 10 Ma, lead-alpha, zircon (Schi1ling, 1965) 

(Tertiary). 

Rocks intruded: Patsy Mine Volcanics (Tertiary). 

Aeromagnetic expression: 

12 Index of Granitic Rock Masses in Nevada 

Anomaly: Low (long-wavelength, low-amplitude). 

Inferred source: Not highly magnetic. 

Remark: Exposed rocks occur near south flank of 

anomaly. 

Mining activity: None. 

Selected references: Anderson, 1969; Schilling, 1965. 

CL-4. Alunite 

General location: Northeastern extremity of the 

McCullough Range at Alunite. 

Coordinates: lat 35°58' N., long 114°56' W. 

Land classification: Public domain. 

Area: 13 km2

• 
LINCOLN COUNTY 115° r- _r ---------- ----~ -~- ---

1 

I 

I 

I 

~ z 

::JI 

§I 

~I zl 

ffii i:l 

~I I 

I 

I 

I 

I 

36° ~ 

' ' 

~ ' ' 

Indian Springs 

~ ' ' 

~ ' ' 

""' ' ' 

Figure 4. Locations of plutons in Clark County. 

Accessibility: U.S. Highways 95 and 93 pass about 0.5 

km north of the exposure. A branch of the Union 

Pacific Railroad parallels the highways. 

Composition: Granite. 

Age: Tertiary. 

Mead 

EXPLANATION 

Cenozoic Plutons 

Mesozoic Plutons 

Precambrian Plutons 

Strike-slip fault-Arrows 

indicate lateral movement 

Dashed where uncertain 

10 20 30 KILOMETERS , ____ _L ____ ~ 

Rocks intruded: Overlain by Tertiary volcanics and 

alluvium. 

Clark County 13 
Aeromagnetic expression: 

Anomaly: Common flank of high and low. 

Inferred source: Not highly magnetic. 

Mining activity: The area lies within the Alunite 

district, where gold and alunite were mined in the 

early 1900's; mining operations ceased in the late 

1930's. 

Selected reference: Longwell and others, 1965. 

CL-5. Knob Hill 

General location: Southern Eldorado Mountains, 

south of Nelson and north of Searchlight. 

Coordinates: lat 35°36' N., long 114°49' W. 

Land classification: The eastern part lies within the 

Lake Mead recreation area and the western half is 

designated as public domain, except for local 

patented mining claims near the towns of Nelson 

and Searchlight. 

Area: 150 (Tertiary granite and quartz monzonite) and 

18 (Precambrian granite) km2

• 

Accessibility: U.S. Highway 95 runs southward from 

Railroad Pass and passes within 8 km of the outcrops. Access to the northernmost exposures is by 

way of State Highway 60. 

Composition: Granite and quartz monzonite. 

Age: 26 ( + 4, -2) Ma, K-Ar, biotite-granite (Schilling, 

1965) (Tertiary); 14.0±0.6 Ma, K-Ar, biotitequartz monzonite (Krueger and Schilling, 1971) 

(Tertiary). Some plutonic bodies of Precambrian 

age. 

Rocks intruded: Precambrian gneiss and schist. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northwest-trending). 

Inferred source: About equal in areal extent to 

exposed plutonic rocks. 

Mining activity: Gold and silver have been mined west 

of the town of Nelson. 

Selected references: Krueger and Schilling, 1971; 

Schilling, 1965; Volborth, 1973. 

CL-6. Spirit Mountain 

General location: Newberry Mountains, near the 

southern tip of Nevada. 

Coordinates: lat 35°13' N., long 114°42' W. 

Land classification: The eastern half lies within the 

Lake Mead recreation area and the western part is 

designated as public domain. 

Area: 345 km2

• 

Accessibility: U.S. Highway 95 is west of the exposures 

and State Highway 77 traverses the exposures. 

Composition: Granite. 

Age: Precambrian; Tertiary. 

Rocks intruded: Tertiary granite intrudes Precambrian 

granite. 

14 Index of Granitic Rock Masses In Nevada 

Aeromagnetic expression: 

Anomaly: High (short-wavelength, low-amplitude, 

north-trending) and high (high-amplitude). 

Inferred source: Low-amplitude high has unknown 

source; high-amplitude high is associated with 

andesitic and basaltic extrusive rocks. The plutonic 

rocks are not highly magnetic. 

Mining activity: Lead and silver deposits have been 

mined along the west flank of the Newberry 

Mountains. 

Selected reference: Volborth, 1973. 

CL-7. Crescent Peak 

General location: Northern part of the New York 

Mountains, west of Searchlight. 

Coordinates: lat 35°28' N., long 115°07' W. 

Land classification: The southern part of the exposure 

consists mainly of patented mining claims, and the 

remainder is public domain. 

Area: 2 km2

• 

Accessibility: State Highway 68 is along the north end 

of the New York Mountains within 3 km of the 

exposure. The Union Pacific Railroad passes 

within 13 km of the outcrop. 

Composition: Quartz monzonite. 

Age: 98.9±3 Ma, K-Ar, biotite (Krueger and Schilling, 

1971) (Cretaceous). 

Rocks intruded: Precambrian gneiss. 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected references: Bingler and Bonham, 1973; Schilling 

1965; Krueger and Schilling, 1971. 

CL-8. Northern Lucy Grey Range 

General location: West of the McCullough Range and 

east of Roach Lake. 

Coordinates: lat 35°39' N., long 115°17' W. 

Land classification: Public domain. 

Area: 23 km 2

• 

Accessibility: Interstate 15 and the Union Pacific 

Railroad are approximately 6 km and 4 km west of 

the exposure, respectively. 

Composition: Granite. 

Age: Precambrian. 

Rocks intruded: Surrounded by alluvium. 

Aeromagnetic expression: 

Anomaly: High (north- to northeast-trending, in part 

over exposed rocks). One of the largest magnetic features, in both amplitude and extent, within Nevada. 

Inferred source: Maximum areal extent of source is 

estimated to be 300 km2

• 

Mining activity: None. 

Selected references: Hewett, 1956; Longwell and 

others, 1965. 
LINCOLN COUNTY 

Geology 

Lincoln County (fig. 5) is located in south1~astern 

Nevada entirely within the Basin and Range province, 

which consists of elongated north-south mountain ranges 

separated by wide basins. The crests of the mountain 

ranges are about 900-1,200 m higher than the adjacent 

basins. 

The bedrock of the county consists of 

approximately one-third Cenozoic sedimentary rocks, 

one-third Tertiary volcanic rocks, and one-third igneous, 

metamorphic, and sedimentary rocks that range in age 

from Precambrian to Triassic (Tschanz and Pampeyan, 

1970). 

The rocks have undergone two episodes of thrust 

faulting-one in the Late Cretaceous and early Tertiary 

and one post-Oligocene. The Paleozoic rocks have 

been displaced eastward as much as 26 km over younger 

rocks that are folded into overturned synclines beneath 

the thrust (Tschanz and Pampeyan, 1970). A major 

northeast-trending strike-slip fault of Laramide age, the 

Arrowhead Mine fault, has been inferred by Tschanz and 

Pampeyan (1970) in the southwestern part of the county 

(fig. 5). The fault has an apparent right-lateral 

displacement of about 40 km. Three post-!\1iocene 

left-lateral faults parallel the older right-lateral 

Arrowhead Mine fault. The older structures have been 

offset by basin-and-range faulting and partly covered by 

Cenozoic rocks. 

An east-trending structure named the Timpahute 

Lineament (Ekren and others, 1976, fig. 5) cro~;ses the 

central part of the county. In the western par1t of the 

county, the lineament is expressed by discontinuous 

east-northeast-trending topography from the Timpahute 

Range through the North and South Pahroc Ranges 

(Ekren and others, 1976). Several igneous intrusive 

bodies occur on or near the lineament, which has been 

the locus of recent seismicity in the southern part of the 

North Pahroc Range (Ekren and others, 1976) and is 

north of a west-southwest-trending zone of seismic 

activity. 

The geologic data were extracted and summarized 

from the following: Ekren and others (1 978) and 

Tschanz and Pampeyan (1970). 

Plutons 

Ll-1. Groom Range 

General location: North end of the Groom Range. 

Coordinates: lat 37°35' N., long 115°48' W. 

Land classification: Public domain. 

Area: 1 km2

• 

Accessibility: 8 km southwest of State Highway 25. 

Composition: Granite. 

Age: Cretaceous-Tertiary. 

Rocks intruded: Prospect Mountain Quartzite (Cambrian) and Chisholm Shale (Cambrian). 

Aeromagnetic expression: 

Anomaly: High (northeast-trending, long-wavell ength); outcrops occur along north flank of anomaly. 

Inferred source: Ash-flow tuffs, andesite flows, and 

:related extrusive rocks. 

Mining activity: None. 

Selected references: Ekren and others, 1978; Tschanz 

and Pampeyan, 1970. 

Ll-2. Lincoln Stock 

Gene1ral location: Western part of the Timpahute 

Range. 

Coordinates: lat 37°39' N., long 115°37' W. 

Land classification: Public domain and patented mining claims. 

Area: 2 km2

• 

Composition: Granite. 

Age: 88.1±2.7 Ma, and 92.7±2.9 Ma, K-Ar, biotite 

(Krueger and Schilling, 1971) (Cretaceous). 

Rocks intruded: Guilmette Formation (Devonianlimestone, dolomite, and quartzite), limestone of 

Mississippian age, Chainman Shale (Mississippian), Scotty Wash Quartzite (Mississippian), and 

limestone of Pennsylvanian age. 

Aeromagnetic expression: 

Anomaly: High (same as that referred to in LI-1). 

Inferred source: Unknown. 

Mining activity: Tungsten has been mined in immediate 

vicinity of the pluton. 

Selected reference: Krueger and Schilling, 1971. 

Ll-3.. Worthington Peak 

General location: North end of the Worthington Mounltains. 

Coordinates: lat 37°57' N., long 11Y36' W. 

Land classification: Public domain. 

Area: 3 km2

• 

Accessibility: 33 km northeast of State Highway 25. 

Composition: Granite. 

Age: Cretaceous-Tertiary. 

Rocks intruded: Pogonip Group (Ordovician-limestone), Eureka Quartzite (Ordovician), and Sevy 

Dolomite (Devonian). 

Lincoln County 15 
EXPLANATION 

Cenozoic Plutons-C. denotes small outcrops 

Cenozoic and (or) Mesozoic Plutons-CM denotes small outcrops 

Mesozoic Plutons-M denotes small outcrops 

--~:o......- Strike-slip fault-Arrows 

indicate lateral movement. Dashed where uncertain 

------Normal fault-Dashed 

where uncertain 

• • • Thrust fault-Sawteeth on 

upper plate 

_____ Trace of lineament 

10 20 30 KILOMETERS 

:>-I 

~I Ul 

~I ~I 

~I ~I 

I 

,----------------------~ 

380 r --" 

/'" (CM)} I \ (910 u-;y 

1 ----- I 

I 

I 

I 

I 

L~------------------~- - CLARK COUNTY 

Figure 5. Locations of plutons in Lincoln County. 

16 Index of Granitic Rock Masses in Nevada 

WHITE PINE COUNTY ----------~ 

I 

I 

l 

I 

I 

_________ _j 
Aeromagnetic expression: 

Anomaly: High (northwest-trending, high-amplitude). Outcrops occur along northeast flank. 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Stewart and Carlson, 1978. 

Ll-4. Bristol Range 

General location: West flank of the Bristol Range. 

Coordinates: lat 38°00' N., long 114°37' W. 

Land classification: Public domain. 

Area: 3 km2

• 

Accessibility: 7 km west of U.S. Highway 93 and 9 km 

northwest of the Union Pacific Railroad. 

Composition: Quartz monzonite. 

Age: 27.7±0.9 Ma, K-Ar, hornblende (Armstrong, 

1970a); 34.9±3.3 Ma, K-Ar, hornblende (Johnston, 1972) (Tertiary). 

Rocks intruded: Prospect Mountain Quartzite (Cambrian), Chisholm Shale (Cambrian), Lyndon Limestone (Cambrian), Highland Peak Formation 

(Cambrian-limestone and dolomite), and the 

Guilmette Formation (Devonian-limestone, dolomite, and quartzite). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude). 

Inferred source: · Ash-flow tuff and related extrusive 

rocks. 

Mining activity: None. 

Selected references: Armstrong, 1970a; Johnston, 1972. 

Ll-5. Chief Range 

General location: Southern part of the Chief Range. 

Coordinates: lat 3r41' N., long 114°30' W. 

Land classification: Public domain. 

Area: 6 km2• 

Accessibility: 1 km west of U.S. Highway 93 and Union 

Pacific Railroad. 

Composition: Granodiorite. 

Age: Tertiary. 

Rocks intruded: Prospect Mountain QuartziL~ (Cambrian), Pioche Shale (Cambrian), and Cambrian 

limestone, dolomite, and shale. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude). Main area of 

exposed rocks occurs at the east flank. 

Inferred source: Andesitic flows and related rocks. 

Mining activity: None. 

Selected reference: Stewart and Carlson, 1978.. 

Ll-6. Cedar Range 

General location: Western part of the Cedar Range. 

Coordinates: lat 37°39' N., long 114°18' W. 

Land classification: Public domain. 

Area: 6 km2

• 

Accessibility: 12 km east of U.S. Highway 93. Union 

Pacific Railroad located 5 km southwest of pluton. 

Composition: Granite and diorite. 

Age: Tertiary. 

Rocks intruded: Tertiary intermediate lava and welded 

tuff. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude). 

Inferred source: Maximum areal extent estimated to 

be as much as 15 km2

• 

Mining activity: None. 

Selected reference: Stewart and Carlson, 1978. 

SOUTHERN NYE COUNTY 

Gec:>logy 

The southern part of Nye County (fig. 6) is located 

in southwestern Nevada. 

Volcanic rocks of Tertiary age (27 to 7 m.y.) make 

up at least 90 percent of the outcrops (Ekren and 

others, 1971), and sedimentary rocks of late Precambrian 

and Paleozoic age constitute the remainder. The 

Tertiary rocks consist chiefly of ash-flow tuffs, silicic 

lavas, interbedded ash-fall tuff, and tuffaceous 

sedimentary rocks. Several volcanic centers are 

possible sources for the volcanic rocks. The area is in 

the western part of the Cordilleran miogeosyncline. 

The area consists primarily of alluvial valleys 

separated by north- trending mountain ranges and closed 

basins. Basin-and-range, high-angle, normal faults 

bound the mountain ranges. Two normal fault systems 

are present in the area (Ekren and others, 1971)-an 

early system that consists of two sets of faults that strike 

northeast and northwest, and a later system that strikes 

north. 

References: Cornwall, 1972; Ekren and others, 

1971. 

Plutons 

SN-1. Microgranite of Timber Mountain 

General location: Timber Mountain, west-central Nevada Test Site. 

Coordinates: lat 3r02' N., long 116°23' W. 

Land classification: Nevada Test Site. 

Area: Less than 1 km2

• 

Accessibility: Restricted. 

Composition: Granite. 

Southern Nye County 17 
11 r NORTHERN NYE COUNTY 116o 

38° ~--~------------------ -Ti 

I I 

! ,------------- l i 

I I L__l I 

I . I 

I I (M) 

i I • SN-8 ! c 

I NELLIS AIR FORCE BASE BOMBING AND GUNNERY RANGE r-

~~ L7 I§ 

gl (M) I~ u I ,SN-7 

~I "" II~ i! ~ (C)\/ I I 

I ::--, j) SN-6 .\ (~'----) --(M) -l! 

1 '\b . '.__ I SN-5 "SN-(:) j 

I " ~ 1 SN-3 ~~~ 

I

I . ~. L,_ I NEVADA TEST SITE I! 

37' l ~ i :os~!, ~r 

', !I 

"-J, l __ J ,o s~C)2 11 

""',"" ~ lj 

<;;~~ · -----· ~ ~ercuryn 

~<"k' I 

~' > 

"'-, I~ 

'"" I§ EXPLANATION 

Cenozoic Plutons- C denotes small outcrops 

Mesozoic Plutons-M denotes small outcrops 

10 20 30 KILOMETERS 

', I~ 

"' ' ld I 

""', I 

"" I ', I 

""', ~ I 

I 

',~ 

Figure 6. Locations of plutons in southern Nye County. 

18 Index of Granitic Rock Masses in Nevada 
Age: Tertiary. 

Rocks intruded: Tertiary volcanics. 

Aeromagnetic expression: 

Anomaly: Low (low-amplitude). Exposures occur 

at nose of anomaly. 

Inferred source: Plutonic rock in ring-dike structure 

(Kane and others, 1981). Source is small. 

Mining activity: None. 

Selected references: Carr and Quinlivan, 1966; Byers 

and others, 1976. 

SN-2. Wahmonie Granodiorite 

General location: Southeast of Lookout Peak, southwestern Nevada Test Site. 

Coordinates: lat 36°51' N., long 116°09' W. 

Land classification: Nevada Test Site. 

Area: Less than 1 km2

• 

Accessibility: Restricted. 

Composition: Granodiorite. 

Age: Tertiary (Ekren and Sargent, 1965). 

Rocks intruded: Tertiary volcanic rocks. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength). 

Inferred source: Plutonic rocks that increase areally 

in the subsurface (Bath and others, 1983). 

Mining activity: None. 

Selected references: Ekren and Sargent, 1965; Ponce, 

1981. 

SN-3. Twinridge Stock 

General location: Halfpint Range, northeastern 

Nevada Test Site. 

Coordinates: lat 37°11' N., long 115°58' W. 

Land classification: Nevada Test Site. 

Area: Less than 1 km 2

• 

Accessibility: Restricted. 

Composition: Quartz monzonite. 

Age: Cretaceous (Maldonado, 1981). 

Rocks intruded: Johnnie Formation (Precambrian-siltstone and limestone) and Stirling Quartzite (Pre-

. cambrian). 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, nose). 

Inferred source: Plutonic and volcanic rocks. Plutonic rocks inferred to be very limited (Bath and 

others, 1983). 

Mining activity: None. 

Selected references: Barnes and others, 1965; 

Maldonado, 1981. 

SN-4. Climax Stock 

General location: Southern Belted Range, northeastern Nevada Test Site. 

Coordinates: lat 37°14' N., long 116°03' W. 

Land classification: Nevada Test Site. 

Area: 3 km2

• 

Accessibility: Restricted. 

Composition: Quartz monzonite and granodiorite. 

Age: 101 ±3.2 Ma, fission-track, apatite, sphene, and 

zircon (Naeser and Maldonado, 1981) (Cretaceous). 

Rocks intruded: Stirling Quartzite (Precambrian) and 

Pogonip Group (Ordovician-limestone). 

Aeromagnetic expression: 

Anomaly: High (west flank of high-amplitude 

anomaly). 

Inferred source: Plutonic rocks that increase 

laterally in the subsurface (Bath and others, 1983). 

Mining activity: Tungsten has been mined. 

Selected references: Maldonado, 1977; Naeser and 

Maldonado, 1981. 

SN-5. Gold Meadows Stock 

General location: North-central Nevada Test Site. 

Coordinates: lat 37°14' N., long 116°13' W. 

Land classification: Nevada Test Site. 

Area: 2 km2

• 

Accessibility: Restricted. 

Composition: Quartz monzonite. 

Age:. 93.6±4.3 Ma, fission-track, zircon (Naeser and 

Maldonado, 1981) (Cretaceous). 

Rocks intruded: Stirling Quartzite (Precambrian) and 

Wood Canyon Formation (Precambrian and Cambrian-quartzite, siltstone, and shale). 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, long-wavelength, 

northwest flank). 

Inferred source: Plutonic rocks that increase areally 

at depth (Bath and others, 1983). 

Mining activity: None. 

Selected references: Snyder, 1977; Naeser and 

Maldonado, 1981; Gibbons and others, 1963. 

SN-6. Black Mountain Syenite 

General location: Black Mountain (Black Mountain 

Caldera). 

Coordinates: lat 37°16' N., long 116°37' W. 

Land classification: Nellis Air Force Base Bombing and 

Gunnery Range. 

Area: 21 km2

• 

Accessibility: 23 km northeast of U.S. Highway 95. 

Composition: Syenite. 

Age: Tertiary. 

Rocks intruded: Tertiary volcanics. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, elliptical). 

Southern Nye County 19 
Inferred source: Curvature of anomaly correlates 

with geometric configuration of the caldera. 

Mining activity: None. 

Selected references: Christiansen and Noble, 1965; 

Noble and others, 1965. 

SN-7. Gold Reed 

General location: Southeast flank of Quartzite Mountain, southern Kawich Range. 

Coordinates: lat 37°27' N., long 116°16' W. 

Land classification: Nellis Air Force Base Bombing and 

Gunnery Range. 

Area: Less than 1 km2

• 

Accessibility: 61 km northeast of U.S. Highway 95 and 

42 km southwest of State Highway 25. 

Composition: Granite. 

Age: 98.4±4.3 Ma, biotite (R.F. Marvin, written commun., 1980) (Cretaceous). 

Rocks intruded: Stirling Quartzite (Precambrian). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude). 

Inferred source: Mostly extrusive rocks, based on the 

correlation of similar anomalies with extrusive 

rocks within 20 km of the anomaly center. 

Mining activity: None. 

Selected reference: Ekren and others, 1971. 

SN-8. Cactus Range 

General location: Southwest flank of the Cactus Range. 

Coordinates: lat 3r40' N., long. 116°52' W. 

Land classification: Nellis Air Force Base Bombing and 

Gunnery Range. 

Area: Less than 1 km 2

• 

Accessibility: 38 km northeast of U.S. Highway 95 and 

75 km southwest of State Highway 25. 

Composition: Granite. 

Age: Cretaceous(?). 

Rocks intruded: Nopah Formation (Cambrian-dolomite) and Eleana Formation (Devonian and 

Mississippian-argillite, quartzite, and limestone). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northwest-trending 

southeast flank). 

Inferred source: Ash-flow tuffs and related extrusive 

rocks. 

Mining activity: None. 

Selected reference: Stewart and Carlson, 1978. 

20 Index of Granitic Rock Masses in Nevada 

NORTHERN NVE COUNTY 

Geology 

The northern part of Nye County, north of the 38th 

parallel (fig. 7), is centrally located within the Basin and 

Range province, which is characterized by a series of 

north- to northeast -trending mountain ranges separated 

by alluvial basins developed during late Tertiary time. 

The ranges are largely composed of a thick sequence of 

Tertiary rhyolitic flows and welded and nonwelded silicic 

ash-flow tuffs. Granitic rocks within the county intrude 

a wide variety of pre-Cenozoic sedimentary rocks, 

ranging in age from late Paleozoic to Mesozoic. The 

intrusives generally are exposed along steep, tilted range 

fronts marked by high-angle normal faults where erosion 

has stripped away the Tertiary cover. 

Tertiary granitic intrusions occurring along the east 

margin of the county (White Pine and Grant Ranges) 

intrude rocks consisting of limestone, dolomite, and 

minor amounts of shale and quartzite, and ranging in age 

from Early Cambrian to Devonian. The structure is 

dominated by north-trending folds and thrusts developed 

during Laramide time (Sevier orogeny) in the late Mesozoic. These structures are cut by a series of low-angle 

faults that placed younger rocks over older rocks. 

In the central part of the county (Toquima and 

Toiyabe Ranges), Mesozoic and Cenozoic plutonic rocks, 

mostly quartz monzonite and granodiorite, intrude a 

wide variety of lithologic assemblages: (1) upper Paleozoic and Mesozoic rocks of siliceous and volcanic 

assemblage, predominantly composed of chert, argillite, 

and greenstone; (2) shale and chert of a lower Paleozoic 

siliceous assemblage; (3) phyllite, shale, and limestone of 

a lower Paleozoic transitional assemblage; and ( 4) 

quartzite, siltstone, and carbonates of a lower Paleozoic 

carbonate assemblage. 

Rocks underlying north-central Nye County have 

undergone at least two major periods of deformation 

during Paleozoic and Mesozoic time. During the 

Antler orogeny, in Late Devonian and Early Mississippian time, siliceous and volcanic assemblage rocks to the 

west were thrust eastward over transitional and 

carbonate assemblages. During the Sonoma orogeny, 

in Late Permian and Early Triassic time, a thick 

accumulation of chert, limestone, shale, and phyllite in 

the western part of the county was transported eastward 

along the Golconda thrust. Both events led to the 

juxtaposition of the diverse facies described above. 
z 

0 

~ 

':1' 

CD 

.. 

:::J 

z 

'< 

CD 

0 

0 

c 

:::J 

~ 

~ 

"' (C) NN-10b 

(M) 

" · ...-~yNN-11 

~-.::>'- '\ 

~~ 

~~ ~-?~ <'~)._ 

-yo> 

0~ />~'\ EXPLANATION 

().,NN-3 

116° EUREK~ COUN_I~ - ~' 

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NN-1 o ~~1\t~ ,-, 

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0 ~l'y 

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~ I 

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I~ I 

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I 

Cenozoic Plutons-C. denotes small outcrops 

Cenozoic and (or) Mesozoic Plutons-CM denotes small outcrops 

Mesozoic Plutons-M denotes small outcrops 

§'\Tonopah (CM) 

38° '---- ::.:_:_L_- -----------------

,----------------~ __L _ J LINCOLN COUNTY 

Thrust fault-Sawteeth on 

upper plate 

Trace of lineament-Dashed where uncertain 

Figure 7. Locations of plutons in northern Nye County. 

SOUTHERNNYECOUNTY 

10 20 30 KILOMETERS 
East of the Toiyabe Range, Mesozoic and Cenozoic granitic rocks intrude thick sequences of intercalated 

clastic, carbonate, and metavolcanic rocks of late Paleozoic(?) and Mesozoic age. These intruded rocks include the Gabbs, Sunrise, Luning, and Pablo Formations, 

present to the west in adjoining Mineral County. Deposition was interrupted during the Jurassic by the Nevada 

orogeny. Folding and thrusting associated with this 

event were directed southward and eastward. The 

primary reference for northern Nye County is Kleinhampl and Ziony (1967). 

Plutons 

NN-1. Railroad and Silver Springs 

General location: West flank of the southern White 

Pine Range. 

Coordinates: lat 38°52' N., long 115°29' W. 

Land classification: Humboldt National Forest. 

Area: 4 km2

• 

Accessibility: State Highway 20 passes within 7 km of 

the outcrop. 

Composition: Quartz monzonite. 

Age: Tertiary. 

Rocks intruded: Cambrian shale and limestone. 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, northwest-trending). 

The trend is perpendicular to the exposure trend. 

Inferred source: Plutonic rocks having a maximum 

areal extent of from 5 to 10 km2

• Inference is 

based on occurrences of two minor exposures 

northwest and northeast of the main exposure, but 

within the confines of the anomaly. 

Mining activity: None. 

Selected references: Lumsden, 1964; Moores and 

others, 1968; Schilling, 1965. 

NN-2. Troy Peak 

General location: Adjacent to Timber Mountain in the 

southern Grant Range. 

Coordinates: lat 38°22' N., long 115°34' W. 

Land classification: Humboldt National Forest. 

Area: 27 km2

• 

Accessibility: A light-duty improved road passes within 

3 km of the main exposure and intersects U.S. 

Highway 6 at Currant. 

Composition: Quartz monzonite and granodiorite. 

Age: 23 ( + 4,-2) Ma,K-Ar, biotite (Schilling, 1965) 

(Tertiary). 

22 Index of Granitic Rock Masses in Nevada 

Rocks intruded: Prospect Mountain Quartzite (Cambrian), Pole Canyon Limestone (Middle Cambrian), and Pogonip Group (Ordovician-limestone). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength, 

north-trending, south flank). 

Inferred source: Plutonic rocks that extend somewhat 

discontinuously northward from exposed rocks for 

a distance of 40 km. Maximum areal extent may 

be as much as 100 or 150 km2

• 

Mining activity: None. 

Selected reference: Schilling, 1965. 

NN-3. Black Butte 

General location: Southeast of the Monitor Range. 

Coordinates: lat 38°06' N., long 116°47' W. 

Land classification: Public domain. 

Area: Less than 1 km 2

• 

Accessibility: U.S. Highway 6 lies 2.5 km north of the 

exposure. 

Composition: Granodiorite. 

Age: Jurassic(?)-Tertiary. 

Rocks intruded: Overlain by Tertiary volcanics. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, north flank). 

Inferred source: Although part of the source may be 

ash-flow tuff and andesitic and basaltic flows, most 

of it is inferred to be granodiorite having a 

maximum areal extent of from 10 to 15 km2

• 

Mining activity: None. 

Selected reference: Stewart and Carlson, 1978. 

NN-4. Clipper Gap 

General location: West flank of the Toquima Range 

along the north border of Nye County. 

Coordinates: lat 39°09' N., long 116°53' W. 

Land classification: Toiyabe National Forest. 

Area: 24 km 2

• 

Accessibility: State Highway 8A passes along the west 

side of Big Smoky Valley about 14 km west of the 

exposures. 

Composition: Quartz monzonite, granodiorite, and 

granite. 

Age: 150 Ma, K-Ar, biotite (Stewart and others, 1977) 

(Jurassic). 

Rocks intruded: Ordovician chert, siltstone, and volcanic rocks. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength, 

elliptical, north-trending). 

Inferred source: Same areal extent as exposed rocks. 

Mining activity: None. 

Selected references: McKee, 1972; Stewart and others, 

1977. 
NN-5. Northumberland 

General location: East flank of the Toquima Range. 

Coordinates: lat 3S0

5S' N., long 116°51' W. 

Land classification: Toiyabe National Forest. 

Area: 2 km2

• 

Accessibility: Light-duty improved State Road S2 

passes along the west side of Monitor Valley, 

approximately 9 km east of the outcrop. 

Composition: Granodiorite. 

Age: 154±3 Ma, K-Ar, biotite (Silberman and McKee, 

1971) (Jurassic). 

Rocks intruded: Pogonip Group (Ordovician-limestone), Ordovician limestone, dolomite, and shale. 

Aeromagnetic expression: None. 

Mining activities: Disseminated gold deposits have 

been mined. 

Selected reference: Silberman and McKee, 1971. 

NN-6a and 6b. Belmont and Manhattan 

General location: Two large exposures of granitic rock, 

within 5 km of one another, occur near the south 

end of the Toquima Range. 

Coordinates: Belmont pluton (6a)-lat 38°39' N., long 

117° w. 

Manhattan pluton (6b )-lat 38°29' N., long 117°04' 

w. 

Land classification: Toiyabe National Forest. 

Area: The northern exposure (6a) and southern exposure (6b) are 14S km2 and 62 km2

, respectively. 

Accessibility: State Highway SA passes within 5 km of 

the Belmont pluton; light-duty State Highway S2, 

2.5 km west of the Manhattan pluton crosses the 

Belmont pluton near Belmont. Light-duty State 

Highway 69 traverses the Toquima Range and ends 

at Manhattan. 

Composition: 6a-Granite and quartz monzonite. 

6b-Granite. 

Age: 6a; 76.4±2.S Ma, and 79.6 + 2.0 Ma, K-Ar biotitequartz monzonite (Krueger and Schilling, 1971) 

(Cretaceous). 

6b; Cretaceous. 

Rocks intruded: 6a; Gold Hill Formation (Cambrianquartzite, shale, and limestone) and Ordovician 

shale and limestone. 

6b; Palmetto Formation (Ordovician-shale, limestone, and quartzite) and Ordovician shale and 

limestone. 

Aeromagnetic expression: 

6a; Anomaly: High (low-amplitude plateau). 

Inferred source: Not highly magnetic. 

6b; Anomaly: High (high-amplitude, western half 

of outcrop area). 

Inferred source: Plutonic rock with a maximum areal 

extent of 100 km2

• 

Mining activity: Silver and gold have been mined within 

the Round Mountain, Manhattan, and Belmont 

mining districts. Mineralization occurred in association with Jurassic or Cretaceous granitic intrusives and Tertiary lavas. The principal production 

has come from the younger gold deposits of Manhattan and Round Mountain. 

Selected references: Ferguson, 1924; Ferguson and 

Cathcart, 1954; Krueger and Schilling, 1971. 

NN-7. Black Mountain 

General location: 10 km north of Tonopah in the San 

Antonio Mountains. 

Coordinates: lat 3S010' N., long 117°13' W. 

Land classification: Public domain. 

Area: 5 km2

• 

Accessibility: Interstate Highway 95 lies S km southwest, State Highway SA lies S km east, and State 

Highway S9 lies 9 km west of the outcrop. 

Composition: Diorite. 

Age: 59 Ma, fission track, sphene; 6S Ma, fission track, 

zircon (Carlson and others, 1975) (Cretaceous and 

Tertiary). 

Rocks intruded: Ordovician shale and limestone. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northern extremity). 

Inferred source: Extrusive rocks similar to those exposed south of the pluton. 

Mining activity: None. 

Selected reference: Carlson and others, 1975. 

NN-8. Toiyabe Range 

General location: Northwest of the town of Round 

Mountain, along the east flank of the Toiyabe 

Range. 

Coordinates: lat 39°02' N., long 117°13' W. 

Land classification: Toiyabe National Forest. A small 

segment of land (1 km2

) is designated as Indian 

Trust Allotments along the east margin of the 

southernmost exposure. 

Area: Beginning with the northernmost and moving 

southward, the five exposures encompass 30, 13, 1, 

10, and 10 km2

, respectively. 

Accessibility: All intrusives are within 5 km west of 

State Highway SA, which passes along the west side 

of Big Smoky Valley. 

Composition: Granite and granodiorite. 

Northern Nye County 23 
Age: 53.9± 1.5 Ma, K-Ar, biotite (Speed and McKee, 

1976); 58 Ma, K-Ar, biotite (Carlson and others, 

1975) (Tertiary). Parts of the pluton could be 

Jurassic-Tertiary in age. 

Rocks intruded: Gold Hill Formation (Cambrianquartzite, shale, and limestone), and Pablo Formation (Mississippian-andesite flows and breccias). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength, 

north-trending), associated with rocks mapped as 

quartz monzonite and granodiorite. 

Inferred source: Maximum areal extent of these 

rocks 

is estimated to be 50 km 2

• 

Mining activity: Tungsten has been mined along the 

west margin of the southernmost outcrop. 

Selected references: Stewart and others, 1977; Carlson 

and others, 1975; Speed and McKee, 1976. 

NN-9. Broad Creek 

General location: East flank of the Toiyabe Range, 

approximately 14 km northwest of the town of 

Round Mountain and about 13 km south of the 

stocks described above as NN-8. 

Coordinates: lat 38°46' N., long 117°13' W. 

Land classification: Toiyabe National Forest. 

Area: 7 km2

• 

Accessibility: Outcrop is easily accessible from Highway 8A, which passes within 1.6 km of the 

exposure. 

Composition: Quartz monzonite. 

Age: Tertiary. 

Rocks intruded: Palmetto Formation (Ordovicianshale, limestone, and quartzite), Pablo Formation 

(Mississipian-andesite flows and breccias), and 

Darrough Felsite (Tertiary). 

Aeromagnetic expression: 

Anomaly: High (northwest-trending), orthogonal to 

northeast -trending mapped outline of plutonic 

rock. 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Stewart and Carlson, 1978. 

NN-1 Oa and 1 Ob. Union Mining District 

General location: West flank of the Shoshone Mountains. The northernmost body (lOa) is centered 

near lone and the southernmost body (lOb) occurs 

near the boundary of the district, approximately 3.4 

km south of Spanish Canyon. 

Coordinates: lat 38°57' N., long 117°35' W., (lOa) and 

lat 38°47' N., long 117°37' W., (lOb). 

24 Index of Granitic Rock Masses in Nevada 

Land classification: The district lies within the Toiyabe 

National Forest except for a small area immediately surrounding the town of lone. 

Area: The outcrop near lone (lOa) is 1 km2 and the 

exposure south of Spanish Canyon (lOb) is less 

than 1 km2

• 

Accessibility: An unimproved light -duty road passes 

along the middle of lone Valley, through the town 

of lone. The road passes within 10 km of the 

southern exposure. 

Composition: lOa-Granodiorite, diorite, and quartz 

diorite. 

lOb-Quartz monzonite. 

Age: lOa-Mesozoic (Jurassic-Cretaceous). 

lOb-Mesozoic (Jurassic-Cretaceous). 

Rocks intruded: lOa-Pablo Formation (Mississippian-andesite flows and breccias). 

lOb-Dunlap Formation (Lower Jurassic sandstone, 

siltstone, and dolomite). 

Aeromagnetic expression: 

lOa-Anomaly: High (long-wavelength, northwesttrending, southeastern margin). 

Inferred source: Unknown. 

lOb-Anomaly: None. 

Mining activity: Gold has been mined within the lone 

area (lOa). 

Selected references: Silberling, 1959; Vitaliano, 1963. 

NN-11. Royston Hills 

General location: South of the Shoshone Mountains. 

Coordinates: lat 38°31' N., long 117°37' W. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: Unimproved State Highway 89 is located 

approximately 1.6 km east of the outcrops. 

Composition: Diorite. 

Age: Jurassic-Cretaceous. 

Rocks intruded: Luning Formation (Upper Triassiclimestone, dolomite, conglomerate, and shale). 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Stewart and Carlson, 1978. 

NN-12a, 12b, and 12c. Paradise Range 

General location, 12a: North of Sherman Peak along 

the east edge of the Paradise Range; referred to as 

the Lodi Hills pluton. 

Coordinates: lat 38°59' N., long 117°44' W. 

Land classification: Toiyabe National Forest. 

Area: 4 km2

• 

Accessibility: State Highway 91 rraverses the Paradise 

Range just north of Gabbs, 9 km south of the main 

outcrop. 

Composition: Granite. 
_Age: 46.9±2.0 Ma, K-Ar, biotite (Krueger and Schilling, 1971) (Tertiary). Parts of the pluton could be 

Jurassic-Tertiary. 

Rocks intruded: Pablo Formation (Mississippianandesite flows and breccias). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northwest-trending, 

southeast margin). 

Inferred source: Unknown; maximum areal extent 

estimated to be 15 km2

• 

Mining activity: None. 

Selected reference: Stewart and Carlson, 1978. 

General location, 12b: Approximately 10 km north of 

Gabbs. 

Coordinates: lat 38°59' N., long 117°53' W. 

Land classification: Public domain. 

Area: 8 km2

• 

Accessibility: State Highway 23 passes about 5 km west 

of the pluton and an unimproved road passes 1.6 

km to the east. 

Composition: Granite, granodiorite, and diorite. 

Age: Tertiary. 

Rocks intruded: Luning Formation (Upper Triassiclimestone, dolomite, conglomerate, and shale). 

Aeromagnetic expression: 

Anomaly: High (northeast-trending, north margin). 

See previous discussion. 

Inferred source: Unknown; maximum extent estimated to be 50 km 2

• 

Mining activity: Tungsten has been mined along the 

south margin of the outcrop. 

Selected references: Krueger and Schilling, 1971; 

Vitaliano, 1963; Vitaliano and Callaghan, 1963. 

General location, 12c: 1.6-12 km east and southeast of 

Gabbs, in the Paradise Range. The large exposure 

southeast of Gabbs is referred to in the literature as 

the Gabbs pluton. 

Coordinates: The outcrops are centered around lat 

38°51' N., long 117°51' W. 

Land classification: Toiyabe National Forest. 

Area: 15 km 2

• 

Accessibility: State Highway 23, provides easy access to 

the west flank of the Paradise Range. A few 

unimproved roads provide access to mining claims 

along the east flank. 

Composition: Granodiorite. 

Age: Cretaceous-Tertiary. 

Rocks intruded: Luning (Upper Triassic-limestone, 

dolomite, conglomerate, and shale), Gabbs (Triassic-limestone, dolomite, and siltstone), and 

Sunrise (Jurassic-limestone, dolomite, and siltstone) Formations. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, gentle north flank, 

approximately circular). 

Inferred source: Unknown; may be southeast subsurface extension of exposed rocks; maximum areal 

extent estimated to be from 5 to 20 km2

• 

Mining activity: Lithium has been mined about 3 km 

east of Gabbs. 

Selected references: Krueger and Schilling, 1971; 

Vitaliano, 1963; Vitaliano and Callaghan, 1963. 

NN--13. Monte Christo Mountains 

General location: Southern Monte Christo Mountains 

Coordinates: lat 38°59' N., long 118°09' W. 

Land classification: Public domain. 

Area: 18 km2

• 

Accessibility: Southern Monte Christo Mountains lie 

approximately 13 km west of State Highway 23. 

Several improved mining roads traverse the area. 

Composition: Quartz monzonite and granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Excelsior Formation (Middle Triassic(?)-volcanics ). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, north-trending, elliptical). 

Inferred source: Areal extent estimated to be the 

same as that of exposed rocks. 

Mining activity: None. 

Selected reference: Kleinhampl and Ziony, 1967. 

ESMERALDA COUNTY 

Geology 

Esmeralda County is located in southwestern 

Nevada, adjacent to the California border; its geology is 

arcuate ranges and intervening valleys. 

Outcrops in the county consist of sedimentary, 

igneous, and metamorphic rocks of late Precambrian to 

Holocene age. Precambrian and Cambrian rocks occur 

in the southern two-thirds of the county and are 

metamorphosed along the contact with igneous intrusives. 

Ordovician rocks are found throughout the county, but 

Silurian, Devonian, and Pennsylvanian rocks are absent; 

Permian strata are sparse. 

Mesozoic sedimentary rocks occur in the northern 

part of the county. Granitic rocks of Jurassic age and 

younger are present throughout the county. Because 

the plutonic rocks are lithologically similar to those of the 

Sierra Nevada, Albers and Stewart (1972) suggested that 

the plutonic bodies (fig. 8) are probably a continuation of 

the Sierra Nevada batholith. 

Esmeralda County 25 
--.......... , 

......... 

' ' ' ' 

-----

EXPLANATION 

II ::::::1

notes 

1: 

small 

:I::::~M outcrops d~ Trace of lineament 

10 20 30 KILOMETERS 

Figure 8. Locations of plutons in Esmeralda County. 

26 Index of Granitic Rock Masses in Nevada 

.o<f (M) 

~~ ES-8 

~Q) //"'f.. 

~'t:f (IJ I ~ \'# I ~ I 

•(M) \~ ES-7 

0<::-

~ Q) o'b . -oC5 

(M) - ~ ES-4 ~ 

--e.\ 

•) 

/ 

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(M) I 

ES- 91 

~ I 

I 

I 
Tertiary rocks include tuff, lava flows, volcanic 

breccia, and sedimentary rocks. The volcanic rocks 

range in composition from rhyolite to basalt and 

represent various periods of volcanic activity. 

A zone approximately 482 km long and 80-161 km 

wide (Albers and Stewart, 1972) forms a transition 

between the northwest-trending Sierra Nevada block to 

the west and the north-northeast-trending ranges of the 

Great Basin province to the east. One of the major 

structures in the county is an orocline that is well 

developed in the Silver Peak-Palmetto-Montezuma 

Range (Albers, 1967). · The arcuate shape, convex to the 

south, suggests drag caused by right-lateral shearing 

(Albers and Stewart, 1972). Oroclines are present in 

other parts of the county but are not as well 

developed. Right-lateral strike-slip faults are present in 

the county and include: (1) Death Valley-Furnace 

Creek fault zone, which has apparent right-lateral 

movement, with a separation of at least 29 km within the 

county (Albers and Stewart, 1972). (2) Soda Spring 

Valley fault, which is mainly in Mineral County but 

extends into Esmeralda County and has a separation of at 

least 13 km. (3) A fault in the Cedar Mountains that is 

considered to be part of a major fault zone, 805 km long, 

called the Walker Lane (Locke and others, 1940). 

Thrust faults are very common in the pre-Tertiary 

rocks, where at least 50 percent of the contacts between 

pre-Tertiary rocks are thrusts (Albers and Stewart, 1972) 

that formed largely in conjunction with development of 

the oroclinal structures and the intrusion of the quartzmonzonite plutons. High-angle normal faults of preTertiary and Tertiary age are very common and cut the 

older structures. 

References: Albers, 1967; Albers and Stewart, 

1972. 

Plutons 

ES-1. Grapevine Peak 

Location: Northeast flank of Grapevine Peak. 

Coordinates: lat 37°02' N., long 117°07' W. 

Land classification: Public domain; 0.5 km from the 

north boundary of Death Valley National Monument. 

Area: 4 km2

• 

Accessibility: 6 km southeast of State Highway 72 and 

14 km northeast of California State Highway 190. 

Composition: Monzonite and diorite. 

Age: Tertiary. 

Rocks intruded: Nopah Formation (Cambrian-dolomite) and Pogonip Group (Ordovician-limestone). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northern steep gradient). 

Inferred source: Unknown; presumed to be plutonic 

rocks. 

Min:ing activity: None. 

Selected reference: Albers and Stewart, 1972. 

ES-2. Sylvania 

General location: The pluton occurs in the Sylvania 

Mountains, and extends southeastward to Slate 

Ridge and Gold Mountain. 

Coordinates: lat 37°19' N., long 117°31' W. 

Land classification: Predominantly public domain, private land in the Sylvania Mountains area, and 

patented mining claims in the Gold Mountain and 

Slate Ridge area. 

Area: 244 km 2

• 

Accessibility: Approximately 2 km south of State Highway 3 to the northwest exposure of the pluton, 

approximately 1 km southwest of State Highway 71 

to the northeast exposure of the pluton. Dirt 

roads common throughout the area. 

Composition: Quartz monzonite. 

Age: 149±6 and 153±5 Ma, K-Ar, biotite (Albers and 

Stewart, 1972)(Jurassic). 

Rocks intruded: Wyman Formation (Precambrian-siltstone and limestone). 

Aeromagnetic expression: 

Anomaly: Low (high-amplitude, long-wavelength, 

northwestern trend) associated with western twothirds of main exposed mass. High (low-amplitude, 

short -wavelength) associated with eastern third of 

main exposed mass. Highs (high-amplitude, elongate, east to northeast trend) associated with small 

plutonic rock masses to south. 

Inferred sources: Positive anomalies form an 

elliptical ring that conforms approximately with the 

outcrop pattern of the two southern bodies and 

with the eastern third of the main body. The low 

is inferred to be caused by a northwest-trending 

belt of basalts that presumably has high-intensity, 

reversely polarized, total magnetization. The 

maximum areal extent of the inferred sources of 

highs is approximately the same as that of the 

exposed rocks. 

Mining activity: Lead, silver, and gold have been mined. 

Selected reference: Albers and Stewart, 1972. 

ES-3. Palmetto 

General location: Southern part of Silver Peak Range, 

western half of Palmetto Mountains. 

Coordinates: lat 37°34' N., long 117°51' W. 

Esmeralda County 27 
Land classification: Predominantly public domain, private lands, and patented mining claims. 

Area: 170 km2

• 

Accessibility: Approximately 5 km east of State 

Highway 3A. State Highway 3 intersects the southern exposure of the pluton. 

Composition: Quartz monzonite. 

Age: 129±6 Ma, K-Ar, hornblende; and 188±7 Ma, 

K-Ar, biotite (Albers and Stewart, 1972) (Jurassic 

and Cretaceous). 

Rocks intruded: Harkless Formation (Lower Cambrian-claystone and limestone), Emigrant Formation (Middle to Upper Cambrian-claystone 

and limestone), and Palmetto Formation (Ordovician-shale, chert, limestone, and quartzite). 

Aeromagnetic expression: 

Anomaly: Highs (northwest-trending belt of highs). 

Lows (low-amplitude). Highs (long-wavelength). 

Inferred source: Belt of highs is associated with 

plutonic rocks; lows are associated with small exposures of basalt, presumably possessing reversed 

total magnetization; long-wavelength highs, west of 

the northwestern extremity of the main mass, and 

south of the southeastern extremity of the main 

mass, may reflect buried tracts of plutonic rocks 

having maximum areal extents of from 10 to 25 

km2

• 

Mining activity: Tungsten and gold have been mined 

within or very near the pluton. 

Selected reference: Albers and Stewart, 1972. 

ES-4. Clayton Ridge 

General location: Two adjacent areas-southern Clayton Ridge and west flank of the Montezuma Range. 

Coordinates: lat 37°39' N., long 117°28' W. 

Land classification: Public domain. 

Area: 1 km2

• 

Accessibility: 16 km southeast of State Highway 47. 

Composition: Quartz monzonite. 

Age: Jurassic. 

Rocks intruded: Campito Formation (Precambrian and 

Cambrian-siltstone and quartzite). 

Aeromagnetic expression: 

Anomaly: High (low-amplitude flexure) associated 

with the northern exposure; high (high-amplitude) 

having a northern steep gradient, associated with 

the southern exposure. 

Inferred source: A variety of intrusive and extrusive 

rocks. 

Mining activity: Gold and silver have been mined approximately 8 km south of the quartz-monzonite 

intrusive. 

Selected reference: Albers and Stewart, 1972. 

28 Index of Granitic Rock Masses in Nevada 

ES-5. Dyer 

General location: Northwest flank of the Silver Peak 

Range. 

Coordinates: lat 37°45' N., long 118°00' W. 

Land classification: Public domain. 

Area: 5 km2

• 

Accessibility: Approximately 6 km east of State 

Highway 3A, and 0.5 km east of an improved 

surface road that connects with State Highway 3A. 

Composition: Quartz monzonite. 

Age: 147.0±5 Ma, K-Ar, biotite; 150.2±5 Ma, K-Ar, 

hornblende (Crowder and others, 1973) (Jurassic). 

Rocks intruded: Harkless Formation (Lower Cambrian-claystone and limestone). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelengths 

having a nose associated with exposed rocks. 

Inferred source: Unknown; maximum areal extent is 

about 100 km2

• 

Mining activity: None. 

Selected reference: Crowder and others, 1973. 

ES-6. Mineral Ridge 

General location: East-central part of Mineral Ridge. 

Coordinates: lat 37°45' N., long 117°39' W. 

Land classification: Public domain and patented mining claims. 

Area: 7 km2

• 

Accessibility: Approximately 2 km west of State Highway 47 and approximately 25 km south of U.S. 

Highways 6 and 95. 

Composition: Quartz monzonite. 

Age: 42±2 Ma, K-Ar, biotite; 51±2 Ma, K-Ar, hornblende (Albers and Stewart, 1972) (Tertiary). Parts 

of the pluton could be Mesozoic. 

Rocks intruded: Wyman Formation (Precambriansiltstone and limestone). 

Aeromagnetic expression: None. 

Mining activity: Lithium has been mined 1 km east of 

the intrusive. 

Selected references: Albers, 1967; Albers and Stewart, 

1972. 

ES-7. Paymaster Ridge 

General location: Pluton occurs between the Paymaster Ridge and Clayton Ridge. 

Coordinates: lat 37°45' N., long 117°28' W. 

Land classification: Public domain. 

Area: Less than 1 km 2

• 
Accessibility: 16 km east of State Highway 47 and 

approximately 17 km west of U.S. Highway 95. 

Composition: Quartz monzonite. 

Age: Jurassic-Cretaceous. 

Rocks intruded: Campito Formation, (Precambrian 

and Cambrian-siltstone and quartzite) and Poleta 

Formation (Cambrian-carbonates, limestone, and 

quartzite). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength, 

north flank of anomaly). 

Inferred source: A variety of intrusive and extrusive 

rocks. 

Mining activity: None. 

Selected reference: Albers and Stewart, 1972. 

ES-8. Montezuma 

General location: Exposures of the intrusive are 

located in the northwest flank of the Montezuma 

Range and the southern Paymaster Ridge. 

Coordinates: lat 37°45' N., long 117°17' W. 

Land classification: Predominantly public domain, 

some patented mining claims. 

Area: 6 km2

• 

Accessibility: 8 km west of U.S. Highway 95. 

Composition: Quartz monzonite. 

Age: Mesozoic. 

Rocks intruded: Harkless (Lower Cambrian -claystone and limestone) and Palmetto (Ordovician-shale, chert, limestone, and quartzite) Formations. 

Aeromagnetic expression: 

Anomaly: Short-wavelength anomalies are largely 

attributable to basaltic rocks. 

Inferred source: The granitic rocks have no magnetic 

signature. 

Mining activity: None. 

Selected reference: Albers and Stewart, 1972. 

ES-9. Goldfield Hills 

General location: Northwestern Goldfield Hills. 

Coordinates: lat 37°44' N., long 117°08' W. 

Land classification: Patented mining claims. 

Area: 1 km2

• 

Accessibility: 1 km east of U.S. Highway 95. 

Composition: Quartz monzonite. 

Age: 147±3 Ma, K-Ar, biotite; 170 Ma, fission-track, 

sphene (Ashley and Silberman, 1976) (Jurassic). 

Rocks intruded: Overlain by Tertiary volcanic rocks. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude) having a steep 

northwest flank associated with exposures of igneous rocks. 

Inferred source: Ash-flow tuffs and related extrusive 

rocks. 

Mining activity: None. 

Selected reference: Ashley and Silberman, 1976. 

ES-·1 0. lnyo Batholith 

General location: Northeast flank of the White Mountains. 

Coordinates: Iat 37°51' N., long 118°21' W. 

Land classification: Inyo National Boundary Peak 

Forest. 

Area: 103 km2

• 

Accessibility: 18 km southeast of U.S. Highway 6 and 2 

km west of State Highway 3A. 

Composition: Quartz monzonite. 

Age: 71, 75, and 78 Ma, K-Ar, biotite (Crowder and 

others, 1973); 157 Ma, K-Ar, biotite (Evernden and 

Kistler, 1970) (Jurassic and Cretaceous). 

Rocks intruded: Wyman Formation (Precambriansiltstone and limestone), Reed Dolomite (Precambrian), Harkless (Lower Cambrian-claystone and 

limestone), and Palmetto Formations (Ordovician-shale, chert, limestone, and quartzite). 

Aeromagnetic expression: 

Anomaly: Highly complex mixture of highs and lows. 

Inferred source: Much of the quartz-monzonite terrane is characterized by high-amplitude highs. 

Mining activity: None. 

Selected references: Crowder and others, 1973; 

Evernden and Kistler, 1970. 

ES-·11. Weepah 

General location: Northwest Weepah Hills. 

Coordinates: lat 37°56' N., long 117°30' W. 

Land classification: Public domain. 

Area: 22 km2

• 

Accessibility: 10 km southeast of U.S. Highways 6 and 

95. 

Composition: Quartz monzonite. 

Age: Cretaceous(?). 

Rocks intruded: Wyman (Precambrian-siltstone and 

limestone) and Campi to Formations (Precambrian 

and Cambrian-siltstone and quartzite). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude) connected to the 

high associated with two exposures of the Lone 

Mountain pluton (ES-12). 

Inferred source: Plutonic rocks having a maximum 

areal extent about the same as that of exposures. 

Mining activity: None. 

Selected reference: Albers and Stewart, 1972. 

Esmeralda County 29 
ES-12. Lone Mountain 

General location: Lone Mountain 

Coordinates: lat 38°01' N., long 117°26' W. 

Land classification: Public domain and patented mining claims. 

Area: 67 km 2

• 

Accessibility: 11 km south of U.S. Highways 6 and 95. 

Composition: Quartz monzonite. 

Age: 69± 1.4 Ma, K-Ar, biotite (Silberman and others, 

1975); 63.7 Ma, K-Ar biotite (Edwards and 

McLaughlin, 1972) (Cretaceous). 

Rocks intruded: Wyman (Precambrian-siltstone and 

limestone), Campito (Precambrian and Cambriansiltstone and quartzite), and Harkless (Lower Cambrian-claystone and limestone) Formations; Reed 

Dolomite (Precambrian); and Deep Spring 

Formation (Precambrian-marble, schist, and 

quartzite). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength, 

northwest-trending) associated with the large main 

mass and smaller southeast mass of the pluton. 

High (low-amplitude, isolated) associated with the 

north mass of plutonic rocks. 

Inferred source: The anomaly data suggest that the 

main mass and southeast mass of the Lone 

Mountain pluton are connected in the subsurface 

with the Weepah pluton (ES-11). The north mass 

apparently occurs as an isolated exposure. 

Mining activity: None. 

Selected references: Albers and Stewart, 1972; Bonham and Garside, 1979; Edwards and McLauglin, 

1972; Silberman and others, 1975. 

ES-13. Miller Mountain 

General location: Southeast flank of Miller Mountain. 

Coordinates: lat 38°01' N ., long 118°09' W. 

Land classification: Public domain. 

Area: 1 km2

• 

Accessibility: 2 km north of U.S. Highway 6 and 

approximately 11 km east of State Highway 10 (not 

shown on fig. 8). 

Composition: Quartz monzonite. 

Age: Cretaceous(?). 

Rocks intruded: Campito Formation (Precambrian and 

Cambrian-siltstone and quartzite). 

Aeromagnetic expression: 

Anomaly: High (low-amplitude) at the north margin 

of a crescent-shaped low. 

Inferred source: Exposed rocks. 

Mining activity: Diatomite has been mined, located 2 

km south of the intrusive. 

Selected reference: Albers and Stewart, 1972. 

30 Index of Granitic Rock Masses In Nevada 

ES-14. Candelaria Hills 

General location: Southeast flank of the Candelaria 

Hills. 

Coordinates: Two outcrops: lat 38°08' N., long 117°58' 

W; lat 38°09' N., long 117°57' W. 

Land classification: Public domain. 

Area: 1 km2

• 

Accessibility: One outcrop is approximately 5 km 

southwest of U.S. Highway 95; the other is 

intersected by U.S. Highway 95. 

Composition: Quartz monzonite. 

Age: 78 Ma, K-Ar, muscovite (Carlson and others, 

1975) (Cretaceous). 

Rocks intruded: Palmetto Formation (Ordovicianshale, chert, limestone, and quartzite). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength) 

having a northwest -trending nose, the north and 

southwest flanks of which are associated with two 

small exposures. 

Inferred source: Unknown buried magnetic rock and 

andesitic tuffs and flows and associated extrusive 

rocks. 

Mining activity: None. 

Selected reference: Carlson and others, 1975. 

ES-15. Monte Cristo 

General location: Northeastern Monte Cristo Range. 

Coordinates: lat 38°09' N., long 117°39' W. 

Land classification: Public domain. 

Area: Less than 1 km 2

• 

Accessibility: 9 km northwest of U.S. Highways 6 and 

95. 

Composition: Quartz monzonite. 

Age: 194 Ma, K-Ar, sericite (Carlson and others, 1975) 

(Jurassic). 

Rocks intruded: Palmetto Formation (Ordovicianshale, chert, limestone, and quartzite). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, short-wavelength). 

Inferred source: Andesitic extrusive rocks. 

Mining activity: None. 

Selected reference: Carlson and others, 1975. 

ES-16. Southern Royston Hills 

General location: South Royston Hills. 

Coordinates: lat 38°15' N., long 117°31' W. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: 12 km north of U.S. Highways 6 and 95. 

Composition: Quartz monzonite. 
Age: 202±3 Ma, K-Ar, hornblende (Speed and Armstrong, 1971) (Jurassic). 

Rocks intruded: Excelsior Formation (Middle Triassic 

(?)-greenstone, breccia, and tuffaceous sandstone). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength) 

having a gentle east gradient associated with the 

small exposures. 

Inferred source: Extrusive rocks. 

Mining activity: None. 

Selected reference: Speed and Armstrong, 1971. 

MINERAL COUNTY 

Geology 

Mineral County (fig. 9) is located along the west 

margin of the Basin and Range province. Most of the 

ranges in the county do not display the north to northeast 

trend characteristic of areas to the east. This discordance 

can be attributed to influences such as the northwesttrending Sierra Nevada batholith, immediately to the 

west, and structural features associated with the Walker 

Lane fault zone (Neilsen, 1965). 

The Walker Lane, trending northwest through the 

county, is a zone of deformation that includes extensive 

right-lateral strike-slip faults and low-angle normal 

faults. Deformation probably commenced in Early Jurassic time and has continued through the Cenozoic. A zone 

of high seismic activity, commonly referred to as the 

Nevada seismic zone (Gumper and Scholz, 1971), 

extends north through the county. Two of the 

earthquakes associated with this zone are the Cedar 

Mountains earthquake of 1932 and the Excelsior 

Mountains earthquake of 1934. 

. Most of the ranges and hills within the county 

contain exposures of granitic rock. The granitic masses 

range in size from dikes and small stocks to batholiths, 

such as the Wassuk Range; they consist mainly of quartz 

monzonite but range in composition from diorite to 

granite. The close similarity of textural and compositional characteristics of these granitic masses with 

those in the Sierra Nevada suggest a satellitic association 

with the Sierra Nevada batholith. 

Most of the granitic bodies intrude sedimentary 

and volcanic assemblages of Mesozoic age. Many of the 

intrusions appear to have been along zones of weakness 

associated with folding, thrusting, and lateral faulting 

during Mesozoic time. 

The overabundance of small isolated outcrops of 

intrusive rocks throughout the area makes compilation 

on an individual basis impractical. Therefore, exposures 

have been grouped into distinct geographic areas, 

predominantly mountain ranges and hills (fig. 9). 

Some of the geologic data were summarized from 

Ekren and others (1980). 

Plutons 

M-1. Wassuk Range 

General location: North-northwest-trending range along 

the west border of Mineral County. 

Coordinates: lat 38°35' N., long 118°48' W. 

Land classification: Northern exposures-Walker River Indian Reservation. 

Central exposures-Hawthorne Naval Ammunition 

Depot. 

Southern exposures-Private land and Toiyabe 

National Forest. 

Area: 570 km 2

• 

Accessibility: U.S. Highway 95 passes along the north 

end of the east flank of the W assuk Range. A few 

unimproved roads penetrate the range and 

intersect State Highway 31 that continues south 

along the east flank. Light-duty all-weather State 

Highway 3C passes along the west flank in Lyon 

County. 

Composition: Quartz monzonite, granodiorite, and 

granite. 

Age: 75 Ma, K-Ar, biotite-hornblende (Evernden and 

Kistler, 1970); 78 Ma, K-Ar, biotite; 80 Ma, K-Ar 

biotite; 117 Ma, K-Ar, hornblende; 135 Ma, K-Ar, 

hornblende (Carlson and others, 1975); 144 Ma, 

K-Ar, hornblende (Bingler and others, 1980) 

(Jurassic and Cretaceous). 

Rocks intruded: Excelsior Formation (Middle Triassic 

(?)-greenstone, breccia, and tuffaceous sandstone). 

Aeromagnetic expression: 

Anomaly: Low (high-amplitude, long-wavelength, 

northwest-trending) associated with northern 

exposures of plutonic rocks and basalt. Dipole 

anomalies are associated with central exposures. Highs and a low are associated with 

southern exposures. 

Inferred source: Plutonic rocks that may exhibit 

strong internal contrasts of magnetization; basalt. 

Mining activity: Gold and silver have been mined 

southwest of Mount Grant and west of Bald 

Mountain. 

Selected references: Evernden and Kistler, 1970; Carlson 

and others, 1975; Bingler and others, 1980. 

Mineral County 31 
CHURCHILLCOUNTY 118° 

10 20 30 KILOMETERS 

Figure 9. Locations of plutons in Mineral County. 

M-2. Rawhide-Eagleville District 

General location: Northeastern part of county. 

Coordinates: lat 39°00' N., long 118°18' W. 

Land classification: Public domain. 

32 Index of Granitic Rock Masses in Nevada 

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

® : ·,' ___.;.-- -- , ___ _ "~--::,_ t_.L 

........__./I 

~ 

Area: 13 km2• 

Cenozoic Plutons 

Cenozoic and (or) Mesozoic 

Plutons 

Mesozoic Plutons-M, denotes small outcrops 

Normal fault-Dashed 

where inferred; dotted 

where concealed 

• • Thrust fault-Sawteeth on 

upper plate 

Strike-slip fault-Dashed 

where inferred; dotted 

where concealed 

Trace of lineament-Dashed where uncertain 

Accessibility: State Highway 31 crosses over one of the 

outcrops and terminates. A light-duty road 

extends westward from outcrop and intersects U.S. 

Highway 95. 
Composition: Quartz monzonite. 

Age: Cretaceous-Tertiary. 

Rocks intruded: Excelsior Formation (Middle Triassic-

(?)-greenstone, breccia, and tuffaceous 

sandstone). 

Aeromagnetic expression: 

Anomaly: High (long-wavelength plateau). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 25 km2

• 

Mining activity: Tungsten has been mined within the 

area. 

Selected references: Ross, 1961; Schilling, 1965. 

M-3. Northern Gillis Range 

General location: Northeast of Walker Lake. 

Coordinates: lat 38°53' N., long 118°36' W. 

Land classification: Walker River Indian Reservation. 

Area: 12 km2

• 

Accessibility: U.S. Highway 95 and the Southern 

Pacific Railroad parallel the west flank of the Gillis 

Range and are, respectively, 10 km and 5 km from 

the nearest exposure. A light-duty, all-weather road 

is 2 km north of the north exposures. 

Composition: Granite. 

Age: Cretaceous(?). 

Rocks intruded: Excelsior (Middle Triassic(?)-

greenstone, breccia, and tuffaceous sandstone) and 

Luning (Upper Triassic-limestone, dolomite, 

conglomerate, and shale) Formations. 

Aeromagnetic expression: 

Anomaly: High (west-trending) having a north flank 

associated with the main exposed mass. High (longwavelength) having a west flank associated with the 

north exposure. 

Inferred source: Extrusive rocks. 

Mining activity: None. 

Selected reference: Ross, 1961. 

M-4. Southern Gillis Range 

General location: Northeast of Hawthorne and east of 

Walker Lake. 

Coordinates: lat 38°39' N., long 118°25' W. 

Land classification: Public domain, except for a few 

local patented mining claims. 

Area: 135 km2

• 

Accessibility: U.S. Highway 95 and the Southern 

Pacific Railroad pass along the west flank of the 

Gillis Range and State Highway 23 extends along 

the east margin of the range, intersecting U.S. 

Highway 95 at Luning. 

Composition: Granite. 

Age: 89 Ma, K-Ar, hornblende; 90 Ma, K-Ar, hornblende; and 94 Ma, K-Ar, biotite (Evernden and 

Kistler, 1970) (Cretaceous). 

Rocks intruded: Excelsior (Middle Triassic(?)-

greenstone, breccia, and tuffaceous sandstone) and 

Luning (Upper Triassic-limestone, dolomite, 

conglomerate, and shale) Formations. 

Aeromagnetic expression: 

Anomaly: None associated with main exposure. Highs 

(short -wavelength) associated with southeastern 

extremity of main mass. 

Inferred source: Extrusive rocks. 

Mining activity: Silver has been mined along the east 

flank of the range and gold and silver mined along 

the southwest flank, midway between Hawthorne 

and Luning. 

Selected references: Ferguson and Muller, 1949; 

Evernden and Kistler, 1970. 

M-5. Southern Gabbs Valley Range 

General location: Northeast of Luning in east part of 

county. 

Coordinates: lat 38°32' N., long 118°06' W. 

Land classification: Public domain and several 

patented mining claims. 

Area: 30 km 2

• 

Accessibility: U.S. Highway 95 and Southern Pacific 

Railroad parallel the Gabbs Valley Range on the 

west side, and State Highway 23 provides easy 

access to the northern exposures. 

Composition: Quartz monzonite, granodiorite, and 

diorite. 

Age: Cretaceous(?). 

Rocks intruded: Luning (Upper Triassic-limestone, 

dolomite, conglomerate, and shale), Gabbs (Triassic-limestone, dolomite, and siltstone), and 

Sunrise (Jurassic-limestone, dolomite, and siltstone) Formations. 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude) associated with 

plutonic rocks. 

Inferred source: Plutonic rock inferred to extend 

continuously in the subsurface from northwestern 

to southeastern exposures. Maximum areal extent 

is about 15 km2

• 

Mining activity: None. 

Selected reference: Ross, 1961. 

Mineral County 33 
M-6. Cedar Mountain 

General location: Near the east corner of county. 

Coordinates: lat 38°32' N., long 117°49' W. 

Land classification: Public domain. 

Area: 21 km2

• 

Accessibility: U.S. Highway 95 is 28 km southwest of 

the outcrops. Unimproved mining roads intersect 

Highway 95 at Mina and extend into the area. State 

Highway 89 (Nye County) passes 6 km northeast of 

the outcrop, along the east flank of Cedar 

Mountain. 

Composition: Granodiorite and quartz monzonite. 

Age: 40± 10 Ma, lead-alpha, zircon (Schilling, 1965; 

Marvin and Dobson, 1979) (Tertiary). Parts of 

the pluton could be Mesozoic. 

Rocks intruded: Luning Formation (Upper Triassiclimestone, dolomite, conglomerate, and shale). 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude). 

Inferred source: Granitic rocks. 

Mining activity: None. 

Selected references: Ferguson and Muller, 1949; 

Gianella and Callaghan, 1934; Knopf, 1921; Schilling, 1965; Marvin and Dobson, 1979. 

M-7. Garfield Hills 

General location: Southeast of Hawthorne and north of 

the Excelsior Mountains. 

Coordinates: lat 38°28' N., long 118°21' W. 

Land classification: Predominantly public domain. 

Numerous patented mining claims are scattered 

throughout the area. 

Area: 44 km 2

• 

Accessibility: U.S. Highway 95 and the Southern 

Pacific Railroad pass along the east and north 

flanks of the hills, and State Highway 31 is near the 

west boundary of the hills. 

Composition: Quartz monzonite, granodiorite, granite, 

and diorite. 

Age: Cretaceous(?). 

Rocks intruded: Excelsior (Middle Triassic(?)-

greenstone, breccia, and tuffaceous sandstone), 

Luning (Upper Triassic-limestone, dolomite, 

conglomerate, and shale), Gabbs (Triassic-limestone, dolomite, and siltstone), and Sunrise (Jurassic-limestone, dolomite, and siltstone) Formations. 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude). 

Inferred source: Two easternmost bodies of plutonic 

rocks. Anomalies farther west are associated with 

basalt. 

Mining activity: None. 

34 Index of Granitic Rock Masses in Nevada 

Selected references: Ferguson and Muller, 1949; Ferguson and others, 1954. 

M-8. Pilot Mountains 

General location: Southeast of Mina. 

Coordinates: lat 38°20' N., long 118°00' W. 

Land classification: Public domain. 

Area: 8 km2

• 

Accessibility: U.S. Highway 95 passes 6 km west of the 

outcrops. 

Composition: Granodiorite. 

Age: 68.7±1.8 Ma, K-Ar, biotite (Schilling, 1965) 

(Cretaceous). 

Rocks intruded: Excelsior (Middle Triassic(?)-

greenstone, breccia, and tuffaceous sandstone) and 

Luning (Upper Triassic-limestone, dolomite, 

conglomerate, and shale) Formations. 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude). 

Inferred source: Plutonic rocks; the two principal 

sources of anomalies have areal extents of about 10 

km2 and about 15 km2

, respectively. 

Mining activity: None. 

Selected references: Ferguson and Muller, 1949; 

Phoenix and Cathcart, 1952; Schilling, 1965. 

M-9. Excelsior Mountains 

General location: Southeast of Hawthorne and west of 

the Pilot Mountains. 

Coordinates: lat 38°16' N., long 118°29' W. 

Land classification: The western half of the main 

granitic mass is located within Toiyabe National 

Forest. The eastern outcrops are within public 

domain. 

Area: 123 km2

• 

Accessibility: State Highway 31 borders the northwest 

edge of the Excelsior Mountains. U.S. Highway 95 

and state Highway 10 pass east and southeast of the 

Excelsior Mountains, respectively. 

Composition: Quartz monzonite and granodiorite. 

Age: 86 Ma, K-Ar, biotite; 101 Ma, K-Ar, hornblende; 

102 Ma, K-Ar, hornblende (Evernden and Kistler, 

1970); 92 Ma, K-Ar, biotite (Marvin and Cole, 

1978) (Cretaceous). 

Rocks intruded: Excelsior (Middle Triassic-limestone, dolomite, conglomerate, and shale) and 

Dunlap (Jurassic-sandstone, conglomerate, limestone, and greenstone) Formations. 

Aeromagnetic expression: 

Anomaly: Grouping of short-wavelength, highamplitude highs and lows. 
Inferred Source: Plutonic rocks with areal extent of 

5 km2

• 

Mining activity: Tungsten has been mined along the 

northwest flank of the Excelsior Mountains. 

Selected references: Callaghan and Gianella, 1935; 

Ferguson and others, 1954; Marvin and Cole, 1978; 

Evernden and Kistler, 1970. 

M-1 0. Anchorite Hills 

General location: South of the Wassuk Range. 

Coordinates: lat 38°15' N., long 118°40' W. 

Land classification: Toiyabe National Forest. 

Area: 13 km2

• 

Accessibility: State Highway 31 passes along the east 

edge of the outcrop. 

Composition: Quartz monzonite and granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Overlain by Tertiary volcanic rocks. 

Aeromagnetic expression: None associated with 

granitic rocks. 

Mining activity: None. 

Selected reference: , Ross, 1961. 

M-11. Aurora Mining District 

General location: Southwest of Wassuk Range, near 

the Nevada-California State line (includes two 

outcrops northwest of district). 

Coordinates: lat 38°16' N., long 118°52' W. 

Land classification: Public domain, private land, and 

Toiyabe National Forest. 

Area: 6 km2

• 

Accessibility: State Highway 31 passes 11 km southeast 

of the outcrops. Light -duty Highway 3C is 9 km 

northwest of the south exposures and 10 km 

southeast of the northern exposures. 

Composition: Granite. 

Age: Cretaceous(?). 

Rocks intruded: Excelsior Formation (Middle Triassic 

(?)-greenstone, breccia, and tuffaceous 

sandstone). 

Aeromagnetic expression: 

Anomaly: High (flexure). 

Inferred source: Plutonic rocks. 

Mining activity: None. 

Selected reference: Ross, 1961. 

LYON COUNTY 

Geology 

Lyon County (fig. 10) is located in western Nevada, 

within the western Great Basin. The county lies on the 

east border of the Cretaceous Sierra Nevada batholith. 

The western part of the county is a gradational physiographic and structural transition between the Sierra 

Nevada and the Basin and Range province. 

The granitic bodies in the county are considered to 

be the eastern continuation of the Sierra Nevada batholith (Moore, 1969), with pre-Cretaceous rocks present as 

roof pendants on the batholith. The pre-Cretaceous 

rocks consist of metamorphosed volcanic rocks and 

minor, reworked, volcanic rocks of Triassic and Jurassic 

age. The granitic bodies are overlain unconformably by 

Tertiary volcanic rocks and, to a lesser extent, by basalt 

flows of Tertiary and Quaternary age. 

Deformation occurred during two periods: one 

preceding and accompanying the emplacement of the 

Cretaceous granitic rocks, and another in late Tertiary 

and Quaternary time that caused normal faulting, 

warping, and tilting (Moore, 1969). The major structural 

feature in the area is the Walker Lane fault zone, located 

in the extreme north-northeastern part of the county. 

The geologic data were summarized from Moore (1969). 

Plutons 

L-1. Round Mountain 

General location: Southwestern part of the Pine Grove 

Hills. 

Coordinates: lat 38°30' N., long 119°10' W. 

Land classification: Toiyabe National Forest. 

Area: 12 km2

• 

Accessibility: State Highway 22 is just west of the 

pluton. 

Composition: Quartz monzonite and granodiorite. 

Age: Cretaceous. 

Rocks intruded: Triassic and Jurassic metavolcanic 

rocks. 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Moore, 1969. 

Lyon County 35 
~ §; 

81 

I I 

I 

I 

01 

~1 Silver Springs 

7 

---\ 

\ 

__; 

I 

> 1:-' 

~I 

~~ 

~ \ 0 I 

" t_l 

EXPLANATION l 

Mesozoic Plutons 1 

I 

I 

" 

I 

I 

I 

I 

I o' 

'1(~~ 0~' /lz' '«/ 

)' 

L-2 I I \ ~I 

'----/ I 

___ _L_ _ _j 

10 20 30 KILOMETERS 

Figure 10. Locations of plutons in Lyon County. 

L-2. East Walker River 

General location: Southernmost Pine Grove Hills, 

southeastern part of the county. 

Coordinates: lat 38°33' N., long 118°57' W. 

36 Index of Granitic Rock Masses in Nevada 

Land classification: Public domain, private land, and 

national forest. 

Area: 64 km 2

• 

Accessibility: State Highway 3C intersects pluton. 
Composition: Quartz monzonite and granodiorite. 

Age: Cretaceous. 

Rocks intruded: Triassic and Jurassic metavolcanic 

rocks. 

Aeromagnetic expression: None, or very little. 

Mining activity: Gold and silver have been mined. 

Selected reference: Moore, 1969. 

L-3. Pine Grove Hills 

General location: Central and southern part of the Pine 

Grove Hills. 

Coordinates: lat 38°39' N., long 119°07' W. 

Land classification: Toiyabe National Forest, patented 

mining claims, and public domain. 

Area: 147 km2

• 

Accessibility: Main outcrop is 2 km east of State 

Highway 22 and 5 km west of State Highway 3C. 

Composition: Quartz monzonite and granodiorite. 

Age: 87.0±2.7 and 90.0±2.7 Ma, K-Ar, biotite 

(Krueger and Schilling, 1971) (Cretaceous). 

Rocks intruded: Triassic and Jurassic metasedimentary 

rocks. 

Aeromagnetic expression: 

Anomaly: Highs and lows. 

Inferred source: Pluton having complex distribution 

of magnetization. 

Mining activity: None. 

Selected reference: Krueger and Schilling, 1971. 

L-4. Wilson District 

General location: Eastern part of the county near the 

East Walker River. 

Coordinates: lat 38°46' N., long 119°03' W. 

Land classification: Private land and public domain. 

Area: 90 km 2

• 

Accessibility: State Highway 3C intersects exposures of 

the pluton. 

Composition: Quartz monzonite and granodiorite. 

Age: Cretaceous. 

Rocks intruded: Triassic and Jurassic metavolcanic 

rocks. 

Aeromagnetic expression: 

Anomaly: Highs (low-amplitude). 

Inferred source: Unknown. 

Mining activity: None. 

Selected references: Moore, 1969. 

L-5. Singatse Range 

General location: Outcrops occur all along the Singatse 

Range, west-central part of county. 

Coordinates: lat 38°55' N., long 119°15' W. 

Land classification: Public domain, patented mmmg 

claims, private land, and Bureau of Reclamation 

withdrawals. 

Area: 84 km2

• 

Accessibility: The central part of the outcrop is 4 km 

west of State Highway 3; State Highway 3 intersects 

part of the pluton to the south. The northernmost 

outcrop is 4 km west of U.S. Highway 95 Alternate. 

Composition: Granite, quartz monzonite, and granodiorite. 

Age: Cretaceous. 

Rocks intruded: Triassic and Jurassic metasedimentary 

rocks. 

Aeromagnetic expression: 

Anomaly: Highs (low-amplitude, long-wavelength). 

Inferred source: Weakly magnetized plutonic rocks. 

Mining activity: Copper has been mined at the Yerington 

open pit. 

Selected reference: Moore, 1969. 

L-6. Yerington 

General location: Luth Hill and other unnamed hills 

east and southeast of Yerington and west of 

Wassuk Range. 

Coordinates: lat 38°59' N ., long 119°05' W. 

Land classification: Public domain, patented mining 

claims, and private land. 

Area: 19 km2

• 

Accessibility: Westernmost outcrop is 2 km east of 

State Highway 3; easternmost outcrop is 10 km 

southwest of the Southern Pacific Railroad. 

Composition: Granite, quartz monzonite, granodiorite. 

Age: Cretaceous. 

Rocks intruded: Triassic and Jurassic metavolcanic and 

metasedimentary rocks. 

Aeromagnetic expression: 

Anomaly: High (short-wavelength). 

Inferred source: Easternmost exposure of plutonic 

rocks. 

Mining activity: None. 

Selected reference: Moore, 1969. 

L-7. Mason Butte 

General location: Mason Butte, northeast of the 

Singatse Range. 

Coordinates: lat 39°05' N., long 119°09' W. 

Land classification: Private land. 

Area: 1 km2

• 

Accessibility: 1 km east of State Highway 3 and 5 km 

southwest of the Southern Pacific Railroad. 

Composition: Quartz monzonite and granodiorite. · 

Age: Cretaceous. 

Rocks intruded: Bounded by alluvium. 

Lyon County 37 
Aeromagnetic expression: 

Anomaly: High (long-wavelength); northwestern part 

is associated with the plutonic rock exposure. 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Moore, 1969. 

L-8. Long Valley 

General location: Southeast flank of the Desert 

Mountains. 

Coordinates: lat 39°05' N., long 118°48' W. 

Land classification: Walker River Indian Reservation. 

Area: 4 km2

• 

Accessibility: 10 km northeast of State Highway 3 (U.S. 

Highway 95 Alt.) and 1 km west of U.S. Highway 

95. 

Composition: Quartz monzonite and granodiorite. 

Age: Cretaceous. 

Rocks intruded: Overlain by Tertiary andesitic and 

rhyolitic volcanic rocks. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northwesttrending, elongate, southeast flank). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 25 km2

• 

Mining activity: None. 

Selected reference: Moore, 1969. 

L-9. Desert Mountains 

General location: South flank of the Desert Mountains. 

Coordinates: lat 39°13' N., long 119°03' W. 

Land classification: Public domain. 

Area: Less than 1 km2

• 

Accessibility: 11 km east of State Highway 2B (U.S. 

Highway 95 Alternate) and 9 km north of the 

Southern Pacific Railroad. 

Composition: Quartz monzonite and granodiorite. 

Age: Cretaceous. 

Rocks intruded: Triassic and Jurassic metavolcanic 

rocks. 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, oval). 

Inferred source: Plutonic rocks having a maximum 

areal extent of 1 km2 (buried part). 

Mining activity: None. 

Selected reference: Moore, 1969. 

L-1 o. Churchill Butte 

General location: Churchill Butte, southwest of the 

Lahontan Reservoir. 

Coordinates: lat 39°20' N., long 119°16' W. 

Land classification: Public domain. 

Area: 3 km2

• 

38 Index of Granitic Rock Masses In Nevada 

Accessibility: 2 km north of State Highway 2B and 4 km 

south of U.S. Highway 50. 

Composition: Quartz monzonite and granodiorite. 

Age: Cretaceous. 

Rocks intruded: Triassic and Jurassic metasedimentary 

rocks. 

Aeromagnetic expression: 

Anomaly: Low (long-wavelength). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Moore, 1969. 

CHURCHILL COUNTY 

Geology 

Churchill County (fig. 11), in west-central Nevada, 

can be divided into two topographic areas. The western 

half of the county is dominated by relatively low relief, 

encompasses the Carson Sink, and is underlain by Pleistocene sediments of Lake Lahontan. The eastern part 

is marked by northeast -trending mountain ranges 

separated by intervening graben valleys or low east-west 

divides. 

The county is characterized on the east by Paleozoic rocks and on the west by Mesozoic rocks. The 

Paleozoic assemblage consists of chert, greenstone, and 

clastic and volcanic rocks exposed mainly along the east 

border of the county. Pre-Tertiary rocks exposed in the 

county, with the exception of granitic plutons, are largely 

Middle Triassic to Middle Jurassic in age. The Mesozoic 

sedimentary units consist chiefly of a shallow-water facies 

of conglomerate, sandstone, shale, limestone, and 

dolomite and an offshore facies of dolomite, limestone, 

and subordinate clastic rocks. At several places these 

rocks are metamorphosed; the degree of metamorphism 

usually depends on the proximity to intrusive rock 

masses. 

Most of the granitic rocks found within the county 

have been assigned a Cretaceous(?) age. The only pluton 

assigned a Tertiary age is exposed on the east side of the 

Stillwater Range. The granitic intrusives are chiefly granodiorite and quartz monzonite in compositiQn. 

Historic faults in western Nevada, north of Walker 

Lake, occur within a well-defined, north-trending, arcuate, linear zone known as the "Churchill arc:' (Shawe, 

1965). Many of these faults occur along the margins of 

the large grabens forming Dixie and Pleasant Valleys (in 

Pershing County) and their northern extensions. Faults 

within the arc change from predominantly strike slip at 

the south end (near the Walker Lane fault zone) to 

mainly dip slip at the north end (near the north county 
0 

::T 

c 

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40° - 119° PERSHING COUNTY T ---r------

) 

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Carson 

sink area 

,CH-12 

~----------

MINERAL COUNTY 

Figure 11. Locations of plutons in Churchill County. 

"') CH-6 J.. 

tlf# I 

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CH-4 (M) 

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) 

EXPLANATION 

Cenozoic Plutons 

Cenozoic and (or) Mesozoic Plutons-CM, denotes small outcrops 

Mesozoic Plutons-M, denotes small outcrops 

----~'{\:. 

10 20 30 KILOMETERS cOU~'\'l 1954 Fault scarps-Bar 

and ball on downthrown 

side 
line). In 1954, several earthquakes occurred within the 

county that resulted in considerable damage to manmade 

structures in the Fallon area. Fault scarps are still present 

near Stillwater and in the Dixie Valley-Fairview Peak 

area. Central Churchill County also is within a major 

narrow zone of high seismicity and recent faulting, which 

extends from Owens Valley (in California) to Winnemucca (in Humboldt County), termed the Nevada 

seismic zone (Gumper and Scholz, 1971). 

Much of the geologic information in this 

compilation has been synthesized from Willden and 

Speed (1974). 

Plutons 

CH-1. Topog Peak 

General location: Southwestern part of West Humboldt Range in northwestern part of county. 

Coordinates: lat 39°54' N., long 118°39' W. 

Land classification: Private land and Bureau of 

Reclamation withdrawals of public domain. 

Area: Less than 1 km2 • 

Accessibility: The Southern Pacific Railroad and U.S. 

Highway 95 are 6 km and 9 km, respectively, west 

of the outcrop. U.S. Highway 40 intersects U.S. 

Highway 95 northwest of the area. 

Composition: Quartz monzonite and granodiorite. 

Age: 75.9±1.5 Ma, K-Ar, biotite (Speed and Armstrong, 1971) (Cretaceous). 

Rocks intruded: Jurassic siltstone and limestone. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, short-wavelength). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Speed and Armstrong, 1971. 

CH-2. White Cloud Canyon 

General location: West flank of the Stillwater Range in 

northern part of county. 

Coordinates: lat 39°50' N., long 118°12' W. 

Land classification: Public domain and patented 

mining claims. 

Area: 8 km2

• 

Accessibility: A gravel road flanks the west side of the 

Stillwater Range, passes 2 km west of the outcrop, 

and joins a paved road at the town of Stillwater, 44 

km southwest of the exposure. 

Composition: Granite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Triassic limestone and shale. 

Aeromagnetic expression: None. 

40 Index of Granitic Rock Masses in Nevada 

Mining activity: Gold, silver, and tungsten have been 

mined within the contact metamorphic aureole 

surrounding the pluton; the area is known as the 

White Cloud mining district. 

Selected reference: Willden and Speed, 1974. 

CH-3. I xI Canyon 

General location: East flank of the Stillwater Range. 

Coordinates: lat 39°38' N., long 118°13' W. 

Land classification: Public domain. 

Area: 41 km2

• 

Accessibility: A gravel road, intersecting U.S. Highway 

50, 29 km south of the main exposure, extends 

along the west side of Dixie Valley and passes 2 km 

east of the intrusive body. 

Composition: Quartz monzonite. 

Age: 28±2 Ma, K-Ar, biotite (Speed and Armstrong, 

1971a) (Tertiary). 

Rocks intruded: Triassic shale and siltstone and 

Tertiary volcanic rocks. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, north-trending, 

north and east flanks). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 25 km2

• 

Mining activity: None. 

Selected reference: Speed and Armstrong, 1971. 

CH-4. Meadow Springs 

General location: West flank of the Clan Alpine 

Mountains in the northern half of the county. 

Coordinates: lat 39°42' N., long 117°51' W. 

Land classification: Public domain. 

Area: 6 km2

• 

Accessibility: The nearest maintained road in the 

vicinity of the intrusive is the gravel road extending 

along the west side of Dixie Valley, 23 km west of 

the exposure. 

Composition: Granodiorite and quartz monzonite. 

Age: 103±2 Ma, K-Ar, biotite (Speed and Armstrong, 

1971) (Cretaceous). 

Rocks intruded: Triassic siltstone and sandstone. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, elongate, northern 

flank). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 75 km2

• 

Mining activity: Antimony has been mined several 

kilometers north of the outcrop. 

Selected reference: Speed and Armstrong, 1971. 

CH-5. Tungsten Mountain 

General location: East flank of the Clan Alpine 

Mountains. 

Coordinates: lat 39°41' N., long 117°43' W. 

Land classification: Public domain. 
Area: 2 km2

• 

Accessibility: U.S. Highway 50 passes along the east 

side of Edwards Creek Valley, 14 km southeast of 

the outcrop. 

Composition: Granodiorite. 

Age: 87.4±2 Ma, K-Ar, biotite (Speed and Armstrong, 

1971) (Cretaceous). 

Rocks intruded: Triassic siltstone, mudstone, 

limestone, and conglomerate. 

Aeromagnetic expression: None. 

Mining activity: Scheelite has been mined along the 

contact between granodiorite and Upper Triassic 

rocks. 

Selected reference: Speed and Armstrong, 1971. 

CH-6. Mountain Wells Mining District 

General location: Southern part of the Stillwater 

Range. 

Coordinates: lat 39°27' N., long 118°18' W. 

Land classification: Public domain. 

Area: 5 km2

• 

Accessibility: The main outcrop 10 km west of the 

Dixie Valley improved road and 17.5 km north of 

U.S. Highway 50. 

Composition: Granodiorite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Triassic shale, sandstone, siltstone, 

and dolomite. 

Aeromagnetic expression: 

Anomaly: High (short-wavelength, oval). 

Inferred source: Subsurface extension of southern 

exposure, having a maximum areal extent of about 

5 km2

• 

Mining activity: None. 

Selected reference: Willden and Speed, 1974. 

CH-7. Chalk Mountain 

General location: Southeast edge of Dixie Valley. 

Coordinates: lat 39°20' N., long 118°08' W. 

Land classification: Public domain and local mining 

claims. 

Area: 1 km2

• 

Accessibility: The Dixie Valley improved road and U.S. 

Highway 50 are 1.5 km west and 4 km south, 

respectively, of the southern exposure. 

Composition: Granodiorite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Triassic limestone and dolomite. 

Aeromagnetic expression: 

Anomaly: High (elliptical, nose, north flank). 

Inferred source: Unknown. 

Mining activity: Lead has been mined. 

Selected reference: Willden and Speed, 1974. 

CH-8. Eastgate Mining District 

General location: Southeastern part of county, near 

Lander County line. 

Coordinates: lat 39°13' N., long 117°46' W. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: Main outcrop lies 2 km southeast of State 

Highway 2, which intersects U.S. Highway 50 west 

of Eastgate. 

Composition: Quartz monzonite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Triassic and Jurassic metavolcanic 

rocks. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, short-wavelength; 

north and west flanks). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Willden and Speed, 1974. 

CH-9. Bell Flat 

General location: Southeast of Bell Flat, near Mineral 

County line. 

Coordinates: lat 39°05' N., long 118°03' W. 

Land classification: Public domain. 

Area: Less than 1 km2

• 

Accessibility: State Highway 23 passes along the east 

edge of the exposure. 

Composition: Granodiorite and quartz monzonite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Overlain by Tertiary volcanic rocks. 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Slemmons, 1957. 

CH-1 o. Slate Mountain 

General location: Southeastern part of county, near the 

Mineral County line. 

Coordinates: lat 39°08' N., long 118°14' W. 

Land classification: Public domain. 

Area: 14 km2

• 

Accessibility: The intrusive occurs 5.5 km east of State 

Highway 31. 

Composition: Quartz monzonite and granodiorite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Triassic-Jurassic volcaniclastic rocks 

and limestone. 

Aeromagnetic expression: 

Anomaly: High (nose, southwest flank). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Willden and Speed, 1974. 

Churchill County 41 
CH-11. Sand Springs Range 

General location: Northern half of Sand Springs 

Range, in southern part of county. 

Coordinates: lat 39°11' N., long 118°23' W. 

Land classification: Public domain, U.S. Navy bombing 

target area, and U.S. Department of Energy 

(formerly U.S. Atomic Energy Commission) land. 

Area: 98 km2

• 

Accessibility: U.S. Highway 50 flanks the north edge of 

the pluton and State Highway 31 passes along the 

west side of Fairview Valley, less than 2 km east of 

the outcrop. 

Composition: Granite, granodiorite, and quartz 

monzonite. 

Age: 76±2 Ma, K-Ar, biotite; 79.6±2 Ma, K-Ar, 

biotite (Schilling, 1965) (Cretaceous). 

Rocks intruded: Triassic and Jurassic volcaniclastic 

rocks and limestone. 

Aeromagnetic expression: 

Anomaly: High (low-amplitude). 

Inferred source: Plutonic and volcanic rocks. 

Mining activity: None. 

Selected reference: Schilling, 1965. 

CH-12. Barnett Hills 

General location: Southwestern part of the county, 

southeast of Fallon. 

Coordinates: lat 39°09' N., long 118°36' W. 

Land classification: Public domain and Walker River 

Indian Reservation. 

Area: 2 km2

• 

Accessibility: The outcrop is located about 13 km east 

of U.S. Highway 95. 

Composition: Granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Overlain by Tertiary volcanics. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, short-wavelength, 

northwest-trending, east margin). 

Inferred source: Plutonic and volcanic rocks. 

Mining activity: None. 

Selected reference: Tocher, 1956. 

42 Index of Granitic Rock Masses in Nevada 

LANDER COUNTY 

Geology 

Lander County (fig. 12) is located in central and 

north-central Nevada and is made up of north-northeasttrending mountain ranges separated by wide basins. 

The county is underlain by sedimentary, igneous, 

and metamorphic rocks from Early Cambrian to 

Holocene age. The lower Paleozoic sediments were 

deposited in the Cordilleran geosyncline and are divided 

into two assemblages: (1) carbonate or eastern 

assemblage that forms the eastern ( miogeosyncline) part 

of the geosyncline and consists of limestone, dolomite, 

and minor shale and quartzite; and (2) siliceous and 

volcanic or western assemblage that forms the western 

(eugeosyncline) part of the geosyncline and consists of 

chert, clastic sedimentary, intercalated volcanic, and 

pyroclastic rocks. 

The lower Paleozoic rocks were folded and faulted 

in Late Devonian and Early Mississippian time, during 

the Antler orogeny (Stewart and others, 1977); siliceous 

and volcanic rocks have been thrust eastward over 

carbonate rocks. The axis of the Antler orogeny lies 

near Lander County where, by Middle Pennsylvanian 

time, the orogenic belt had beet) eroded; clastic material 

was deposited in troughs, forming sedimentary rocks 

ranging in age from Pennsylvanian to Permian. 

Mesozoic rocks are represented in the county by 

deposits derived from local uplifts and consist of coarse 

clastic rocks and limestones. Other Mesozoic rocks 

include quartz monzonite and granodiorite of Jurassic 

and Cretaceous age. 

Tertiary rocks consist mostly of volcanic types, with 

intrusive and sedimentary rocks less common. The 

volcanic rocks include tuffs, lavas, and breccias that range 

from rhyolite to basalt. 

The rocks in Lander County have been affected by 

several major orogenic episodes (Stewart and others, 

1977), as follows: 

1. The Antler orogeny (Late Devonian and Early 

Mississippian), during which a thick 

assemblage of siliceous and volcanic rocks was 

transported from west to east along the Roberts Mountains thrust. A carbonate 

assemblage forms the lower plate of this 

thrust. 

2. The Sonoma orogeny (Late Permian and Early 

Triassic), during which the area was subjected 

to folding and faulting. One of the major 

structures that developed was the Golconda 

thrust that transported the siliceous and 

volcanic assemblage eastward. 
EXPLANATION 

-

/ 

(_I 

\ 

Cenozoic Plutons-C. denotes small outcrops 

Cenozoic and (or) Mesozoic Plutons -CM denotes small outcrops 

Mesozoic Plutons-M denotes small outcrops 

Trace of lineament-Dashed 

where uncertain 

....... 

) 

) 

I 

I 

I 

I 

I 

_______ j 

30 KILOMETERS 

L__.--.L __ __,_ _ _ _j 

10 20 

Figure 12. Locations of plutons in Lander County. 

Lander County 43 
3. Basin and range deformation (Tertiary and 

Quaternary), consisting of high-angle normal 

faults bounding uplifted fault-block mountain 

ranges trending east-northeast, resulting in the 

present topography of the county. 

4. The Oregon-Nevada lineament, a major 

structural feature, located in the northeastern 

part of the county. The lineament consists of 

closely spaced, partly en echelon faults 

extending from Oregon into Nevada; it is 

defined in Nevada by north-northwesttrending faults, voluminous lava domes and 

flows of Miocene age, and a conspicuous 

linear aeromagnetic anomaly (Stewart and 

others, 1975). 

The northwest-trending fault zones that define the 

lineament are segmented by northeast-trending basinand-range faults (Stewart and others, 1975). The 

lineament has been interpreted to be the surface 

expression of a deep-seated fracture zone that may have 

a complex history of strike-slip and tensional movement 

(Stewart and others, 1975). 

The geologic data were summarized from Stewart 

and others (1975; 1977). 

Plutons 

LA-1. Copper Canyon Stock 

General location: East flank of Battle Mountain, with 

northernmost outcrops extending into Humboldt 

\County. 

Coordinates: lat 40°36' N., long 117°02' W. 

Land classification: Private land, public domain, and 

patented mining claims. 

Area: 6 km2

• 

Accessibility: Major southern outcrops 4 km west of 

State Highway SA, and northern outcrops 5 km 

southwest of Southern Pacific Railroad tracks. 

Composition: Granodiorite and quartz monzonite. 

Age: 3S.2±0.S Ma, K-Ar, biotite; 3S.2±0.S Ma, K-Ar, 

hornblende (Silberman and McKee, 1971) 

(Tertiary). 

Rocks intruded: Harmony Formation (Cambrian-sandstone, shale, and limestone), Pumpernickel 

Formation (Pennsylvanian and Permian-chert, 

siltstone, and pyroclastics), and Antler sequence 

(Pennsylvanian and Permian-limestone, sandstone, shale, and conglomerate). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northeast flank). 

44 Index of Granitic Rock Masses in Nevada 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 15 km2

• 

Mining activity: Copper and gold have been mined 

along east and southeast flanks of Battle Mountain. 

Selected references: Blake and others, 1979; Silberman 

and McKee, 1971; Theodore and others, 1973. 

LA-2. Trenton Canyon Stock 

General location: West flank of Battle Mountain at 

Trenton Canyon. 

Coordinates: lat 40°37' N., long 117°0S' W. 

Land classification: Private land and public domain. 

Area: 2 km2

• 

Accessibility: 14 km northwest of State Highway SA. 

Composition: Granodiorite. 

Age: S7.0±1.7 Ma, K-Ar, biotite, S7.2±1.7 Ma, K-Ar, 

biotite (Silberman and McKee, 1971) 

(Cretaceous). 

Rocks intruded: Pumpernickel (Pennsylvanian and 

Permian -chert, siltstone, and pyroclastics) and 

Havallah (Pennsylvanian and Permian-sandstone, 

shale, quartzite, and limestone) Formations and 

Antler sequence (Pennsylvanian and Permianlimestone, sandstone, shale, and conglomerate). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, steep north 

gradient). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 15 km2

• 

Mining activity: Copper and gold have been mined along 

the east and southeast flanks of Battle Mountain. 

Selected reference: Silberman and McKee, 1971. 

LA-3. Me Coy Stock 

General location: Northern part of the Fish Creek 

Mountains. 

Coordinates: lat 40°1S' N., long 117°15' W. 

Land classification: Public domain. 

Area: 4 km2

• 

Accessibility: 11 km west of State Highway SA. 

Composition: Granodiorite, quartz monzonite with 

some granite, and diorite. 

Age: S7±2.7 Ma, K-Ar, biotite; 90±2.7 Ma, K-Ar, 

biotite (Krueger and Schilling, 1971), and 153±3 

Ma, K-Ar, biotite (Silberman and McKee, 1971) 

(Jurassic and Cretaceous). 

Rocks intruded: Cane Spring Formation (Triassicsandstone, limestone, and conglomerate), and 

Osobb Formation (Triassic-limestone, dolomite, 

shale, and conglomerate). 

Aeromagnetic expression: 

Anomaly: High (west-trending). 

Inferred source: Extrusive and intrusive rocks. 
Mining activity: None. 

Selected references: Miller and Silberman, 1977; 

Krueger and Schilling, 1971; Silberman and 

McKee, 1971. 

LA-4. Granite Mountain Stock 

General location: Granite Mountain and vicinity, 

northern part of the Shoshone Range. 

Coordinates: lat 40°22' N., long 116°45' W. 

Land classification: Private land, public domain, and 

patented mining claims. 

Area: 11 km2

• 

Accessibility: Main outcrop is 10 km northwest of State 

Highway 21. 

Composition: Granodiorite and quartz monzonite. 

Age: 36.7±0.7 Ma, K-Ar, hornblende; 3S.O±O.S Ma, 

K-Ar, biotite (Silberman and McKee, 1971 ); 

40±20 Ma, K-Ar, biotite; 50± 10 Ma, Pb-Alpha, 

zircon (Marvin and Dobson, 1979) (Tertiary). 

Rocks intruded: Valmy Formation (Ordovician-chert, 

quartzite, greenstone, and pillow lava), Roberts 

Mountains Formation (Silurian and Devonianlimestone ), Slaven Chert (Devonian), Panther 

Canyon Member of the Augusta Mountain 

Formation (Triassic-dolomite, limestone, shale, 

sandstone, and conglomerate). 

Aeromagnetic expression: 

Anomaly: Low (low-amplitude) associated with 

northern exposure. High (high-amplitude) 

associated with central exposure. High (nose) 

associated with southern exposure. 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 15 km2

• 

Mining activity: Gold and clay have been mined in the 

northern part of the Shoshone Range. 

Selected references: Silberman and McKee, 1971; Silberman and others, 1969; Marvin and Dobson, 

1979. 

LA-5. Cain Creek Stock 

General location: 10 km south of the south edge of the 

Fish Creek Mountains near Cain Creek. 

Coordinates: lat 40°00' N., long 117°12' W. 

Land classification: Public domain, and private land. 

Area: 7 km2

• 

Accessibility: 5 km west of State Highway SA. 

Composition: Granodiorite. 

Age: 155±3 Ma, K-Ar, biotite (Silberman and McKee, 

1971) (Jurassic). 

Rocks intruded: Overlain by alluvium and Tertiary 

volcanic rocks. 

Aeromagnetic expression: 

Anomaly: High (elongate, northwest-trending, 

northwest flank). 

Inferred source: Although a small part of anomaly is 

associated with basalt, the predominant source is 

inferred to be plutonic rocks having a maximum 

areal extent of about 15 to 25 km2

• 

Mining activity: None. 

Selected references: Carlson and others, 1975; Silberman and McKee, 1971. 

LA-6. Steiner Spring 

General location: Northern part of the Shoshone 

Mountains. 

Coordinates: lat 39°4S' N., long 117°07' W. 

Land cla·ssification: Public domain. 

Area: 1 km2

• 

Accessibility: 5 km west of State Highway SA. 

Composition: Granodiorite and quartz monzonite. 

Age: Jurassic-Tertiary(?). 

Rocks intruded: Valmy Formation (Ordovician-chert, 

quartzite, greenstone, and pillow lava). 

Aeromagnetic expression: None well-defined. 

Mining activity: None. 

Selected reference: Stewart and others, 1975; 1977. 

LA-7. Iowa Creek Stock 

General location: Northwest flank of the northern 

Toiyabe Range, near Iowa Creek. 

Coordinates: lat 39°50' N., long 117°00' W. 

Land classification: Public domain. 

Area: 1 km2

• 

Accessibility: S km east of State Highway SA. 

Composition: Granite and quartz monzonite. 

Age: 67.9±2.7 Ma, K-Ar, biotite (Silberman and 

McKee, 1971) (Cretaceous). 

Rocks intruded: Valmy Formation. (Ordovician-chert, 

quartzite, greenstone, and pillow lava). 

Aeromagnetic expression: None well-defined. 

Mining activity: None. 

Selected reference: Silberman and McKee, 1971. 

LA-8. Ravenswood Stock 

General location: Shoshone Mountains, near Gilberts 

Creek. 

Coordinates: lat 39°42' N., long 117°12' W. 

Land classification: Public domain. 

Area: 5 km2

• 

Accessibility: S km west of State Highway SA. 

Composition: Granite and quartz monzonite. 

Age: 71.4± 1.4 Ma, K-Ar, biotite (Silberman and 

McKee, 1971) (Cretaceous). 

Rocks intruded: Cambrian quartzite and shale. 

Aeromagnetic expression: 

Anomaly: High (low-amplitude). 

Inferred source: Unknown. 

Lander County 45 
Mining activity: None. 

Selected reference: Silberman and McKee, 1971. 

LA-9. Steiner Creek 

General location: Northwest flank of Simpson Park 

Mountains, 6 km northeast of Steiner Creek. 

Coordinates: lat 39°42' N., long 116°47' W. 

Land classification: Private land. 

Area: 1 km2

• 

Accessibility: State Highway 21 bisects exposure. 

Composition: Granite. 

Age: 168±3 Ma, K-Ar, biotite (Silberman and McKee, 

1971) (Jurassic). 

Rocks intruded: Roberts Mountains Formation (Silurian and Devonian-limestone). 

Aeromagnetic expression: 

Anomaly: High (flat summit). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Silberman and McKee, 1971. 

LA-10. Austin 

General location: Central part of the Toiyabe Range, 

near Austin. 

Coordinates: lat 39°28' N., long 117°00' W. 

Land classification: Toiyabe National Forest, private 

land, and patented mining claims. 

Area: 161 km2

• 

Accessibility: U.S. Highway 50 bisects the mam 

exposures. 

Composition: Quartz monzonite and granodiorite, 

minor diorite, and alaskite. 

Age: 157 Ma, K-Ar, biotite (Krueger and Schilling, 

1971); 73 Ma, K-Ar, biotite; 80 Ma, K-Ar, 

muscovite; 138 Ma, K-Ar, biotite; 152 Ma, K-Ar, 

hornblende; and 155 Ma, K-Ar, biotite (Carlson 

and others, 1975) (Jurassic and Cretaceous). 

Rocks intruded: Cambrian quartzite and shales, Valmy 

Formation (Ordovician-chert, quartzite, greenstone, and pillow lava), and Slaven Chert (Devonian). 

Aeromagnetic expression: 

Anomaly: High associated with northern exposure. 

High (high-amplitude) that transects two major 

southern exposures and forms part of a magnetic 

lineament that extends for at least 100 km. 

Inferred source: Unknown. 

Mining activity: None. 

Selected references: Krueger and Schilling, 1971; Carlson and others, 1975. 

46 Index of Granitic Rock Masses in Nevada 

EUREKA COUNTY 

Geology 

Eureka County (fig. 13) is located within the northcentral part of the Basin and Range province, where most 

of the ranges trend in a north to northeast direction and 

are bounded by fault scarps on one or both sides. 

Movement along many of the faults has tilted the ranges 

eastward or southeastward. This tilting of the ranges is 

clearly shown by steep fault scarps along the west borders 

and the gradual merging with alluvium on the east flanks. 

The most prominent feature of the geology in the 

county is the Roberts Mountains thrust, a major 

structural element of the Antler orogenic belt. This 

thrust brings into contact thick sections of rock of early 

and middle Paleozoic age that contrast greatly in lithology. The upper plate of the thrust is almost entirely 

siliceous, consisting of sandstone, quartzite, shale, greenstone, and chert, whereas the lower eastern assemblage 

contains a sequence of rocks composed almost entirely of 

carbonates. After the major thrusting event, coarse clastics, eroded from highlands to the west, were deposited 

over the older facies. This overlap assemblage was 

subsequently folded and thrust faulted by intermittent 

orogenic movements during late Paleozoic and Mesozoic 

time. 

During the Mesozoic and extending into Tertiary 

time, many of the granitic rock masses were emplaced 

along zones of structural weakness associated with past 

deformation. The intrusives are chiefly composed of 

quartz monzonite and granodiorite, although several 

exposures are composed of alaskite. Mineralized areas, 

commonly associated with the intrusives, are mainly 

silver-gold-lead-zinc replacement deposits in eastern 

assemblage (carbonate) host rocks. 

The Oregon-Nevada lineament, trending in a 

north-northwest direction, extends into the southwestern 

part of the county. The lineament is marked by closely 

spaced faults, centers of volcanic activity, and a 

conspicuous aeromagnetic anomaly (Stewart and others, 

1975). The lineament may represent the surface 

expression of a deep-seated fracture zone and may be 

related to a system of interrelated strike-slip and tension 

zones. 

Much of the information summarized for Eureka 

County is from Roberts and others (1967). 
Cortez Window 

400 r® 

I {JJ (C) 

~L EU-6 

Keystone Window 

EXPLANATION 

CJ Cenozoic Plutons-C denotes small outcrops 

(C) 

~EU-8 

Cenozoic and (or) Mesozoic Plutons -CM denotes small outcrops 

Mesozoic Plutons-M denotes small outcrops 

• Thrust fault-Sawteeth on 

upper plate 

I 116° 

p-~ 

>- !-

IZ 

I§ 

IZ 

0:: 

I 

? 

--\ 

\ 

\ 

I 

J 

\ 

I 

) 

(CM) ~ o EU-9 1:::c 

________ _j_ _ _j == 

NYECOUNTY O 10 20 KILOMETERS 

Figure 13. Locations of plutons in Eureka County. 

Eureka County 47 
Plutons 

EU-1 a and 1 b. Tuscarora Mountains 

General location, 1a: North-central part of county, 

north of the Lynn mining district. 

Coordinates: lat 40°57' N., long 116°21' W. 

Land classification: Private land (railroad). 

Area: 4 km2

• 

Accessibility: U.S. Highway 40 is 33 km south of the 

outcrops. Western Pacific and Southern Pacific 

Railroads pass 40 km south of the area. A hardsurface secondary road extends northwest from 

Carlin to the Carlin Mine, approximately 4 km 

south of the outcrops. 

Composition: Granodiorite, granite, and diorite. 

Age: 121±5 Ma, K-Ar, biotite (Hausen and Kerr, 

1968) (Cretaceous). 

Rocks intruded: Vinini Formation (Ordovician-chert 

and shale). 

Aeromagnetic expression: 

Anomaly: Highs and lows. 

Inferred source: Plutonic rocks. 

Mining activity: Gold and silver have been mined in the 

immediate vicinity of the northwestern exposure. 

Gold has been mined within the Lynn mining 

district, south and southwest of the exposures. 

General location, 1b: Northwest of Marys Mountain. 

Coordinates: lat 40°50' N., long 116°18' W. 

Land classification: Private land (railroad). 

Area: Less than 1 km2

• 

Accessibility: U.S. Highway 40 and Western Pacific 

Railroad pass 23 km and 30 km south of the area, 

respectively. The Carlin Mine secondary road is 6 

km east of the outcrop. 

Composition: Granite. 

Age: 108±3 Ma, K-Ar, biotite (Morton and others, 

1977) (Cretaceous). 

Rocks intruded: Hamburg Dolomite (Cambrian) and 

Eureka Quartzite (Ordovician). 

Aeromagnetic expression: 

Anomaly: Highs and lows. 

Inferred source: Plutonic rocks. 

Mining activity: The exposure is near the Lynn mining 

district, where gold and silver have been mined. 

Selected references: Morton and others, 1977; Hausen 

and Kerr, 1968. 

48 Index of Granitic Rock Masses in Nevada 

EU-2. Boulder Valley 

General location: Northeast of the Shoshone Range in 

the northern part of the county. 

Coordinates: lat 40°43' N., long 116°27' W. 

Land classification: Private land. 

Area: 3 km2

• 

Accessibility: U.S. Highway 40 is about 4 km south of 

the exposure. Western Pacific and Southern 

Pacific Railroads lie 5 km south of the area. 

Composition: Quartz monzonite. 

Age: Cretaceous-Tertiary(?). 

Rocks intruded: Vinini Formation (Ordovician-chert 

and shale). 

Aeromagnetic expression: 

Anomaly: High (long-wavelength, north-trending, 

west flank). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Roberts and others, 1967. 

EU-3. Buck Rake 

General location: South end of the Tuscarora 

Mountains, north of the Humboldt River. 

Coordinates: lat 40°37' N., long 116°16' W. 

Land classification: Private land (railroad). 

Area: 5 km2

• 

Accessibility: U.S. Highway 40 is 5 km north of the 

main exposure. Western Pacific and Southern 

Pacific Railroads pass about 1.5 km south of the 

area. 

Composition: Quartz monzonite. 

Age: Cretaceous-Tertiary(?). 

Rocks intruded: Jurassic and Cretaceous volcanic 

rocks. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, short-wavelength, 

south flank). 

Inferred source: Unknown. 

Mining activity: Iron has been mined south of the main 

granitic body. 

Selected reference: Roberts and others, 1967. 

EU-4. Dry Hills 

General location: Southern Dry Hills, south of the 

Humboldt River. 

Coordinates: lat 40°27' N., long 116°24' W. 

Land classification: Public domain and private land. 

Area: 22 km 2

• 
Accessibility: State Highway 21 extends southward 

from U.S. Highway 40 and passes 8.5 km west of 

the west exposures. 

Composition: Granodiorite and monzodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Brock Canyon Formation(?) (Permian 

and Pennsylvanian-sandstone) and Permian(?) 

quartz latite porphyry. 

Aeromagnetic expression: 

Anomaly: Low (low-amplitude). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Muffler, 1964. 

EU-5. Cortez Mountains 

General location: Prominent northeast-trending range 

south of the Humboldt River. 

Coordinates: lat 40°19' N., long 116°22' W. 

Land classification: Public domain and private land. 

Area: 138 km2

• 

Accessibility: The westernmost exposure is about 13 

km southeast of State Highway 21. Light-duty 

improved State road 21 passes south of the 

exposures. 

Composition: Granodiorite, quartz monzonite with 

minor diorite, tonalite, and alaskite. 

Age: 125 Ma, K-Ar, biotite-quartz monzonite; 145 Ma, 

K-Ar, biotite-quartz monzonite; 124 Ma, K-Ar, 

biotite-granodiorite; 147 Ma, K-Ar, biotitegranodiorite; 150 Ma, K-Ar, hornblende-diorite 

(Schilling, 1965), and 150 Ma, K-Ar, biotite-quartz 

monzonite (Armstrong, 1970b) (Jurassic and 

Cretaceous). 

Rocks intruded: Brock Canyon Formation (Permian 

and Pennsylvanian-sandstone). 

Aeromagnetic expression: 

Anomaly: Lows (low-amplitude) associated with 

most of the plutonic rocks. High (high-amplitude, 

north flank) associated with basalt. 

Inferred source: Extrusive and intrusive rocks. 

Mining activity: Gold and silver have been mined 

approximately 8 km southwest of the main body in 

the Buckhorn mining district. 

Selected references: Armstrong, 1970b; Gilluly and 

Masursky, 1965; Muffler, 1964; Schilling, 1965; 

Stewart and others, 1975; Stewart and others, 1977; 

Wells and others, 1971. 

EU-6. Walti 

General location: Simpson Park Mountains near the 

west county line. 

Coordinates: lat 39°55' N., long 116°34' W. 

Land classification: Public domain. 

Area: 5 km2

• 

Accessibility: Light-duty improved State road 21 

intersects State Highway 21 and passes within 1 km 

of the western exposures. 

Composition: Granodiorite. 

Age: 33.4±0.7 Ma, K-Ar, biotite (Silberman and 

McKee, 1971) (Tertiary). 

Rocks intruded: Vinini Formation (Ordovician-chert 

and shale) and carbonates (Devonian). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, equidimensional, 

steep north flank). 

Inferred source: Plutonic rocks having a maximum 

areal extent of 15 km2

• 

Mining activity: None. 

Selected references: Silberman and McKee, 1971; 

Stewart and others, 1975. 

EU-·7. Whistler Mountain 

General location: Northwest of Eureka. 

Coordinates: lat 39°38' N., long 116°06' W. 

Land classification: Public domain. 

Area: 23 km2

• 

Accessibility: State Highway 20 passes 3 km east. 

Composition: Quartz monzonite (alaskite?). 

Age: 165 ( + 25, -8) Ma, K-Ar, biotite (Schilling, 1965) 

(Jurassic). 

Rocks intruded: Paleozoic carbonates and Vinini 

Formation (Ordovician-chert and shale). 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected references: Merriam and Anderson, 1942; 

Schilling, 1965. 

EU-·8. Wood Cone Peak 

General location: South Mahogany Hills. 

Coordinates: lat 39°29' N., long 116°06' W. 

Land classification: Public domain. 

Area: 3 km2

• 

Accessibility: U.S. Highway 50 passes 20 km north of 

the outcrop. 

Composition: Granodiorite. 

Age: 34.1 ± 1.5 Ma, K-Ar, biotite (Marvin and Cole, 

1978) (Tertiary). 

Rocks intruded: Pogonip Group (Ordovician-limestone) and Eureka Quartzite (Ordovician). 

Aeromagnetic expression: 

Anomaly: High (short wavelength, elliptical northtrending, steep north flank). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 10 km2

• 

Mining activity: None. 

Selected reference: Marvin and Cole, 1978. 

Eureka County 49 
EU-9. Ninemile Canyon 

General location: North Antelope Range. 

Coordinates: lat 39°13' N., long 116°17' W. 

Land classification: Public domain. 

Area: 1 km2

• 

Accessibility: The outcrop is located 35 km south of 

U.S. Highway 50, and 10 km east of State Highway 

82. 

Composition: Quartz monzonite, grandiorite. 

Age: Jurassic-Tertiary(?). 

Rocks intruded: Pogonip Group (Ordovician-limestone). 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Roberts and others, 1967. 

WHITE PINE COUNTY 

Geology 

White Pine County (fig. 14) is located in eastcentral Nevada where elongated north-trending 

mountain ranges are separated by wide basins. 

The county is underlain by rocks of sedimentary, 

igneous, and metamorphic origin, that range from Precambrian to Pliocene in age. The Precambrian to Lower 

Triassic sedimentary rocks make up the Cordilleran 

miogeosyncline. Middle Triassic, Upper Triassic, or 

Jurassic sedimentary rocks have not been identified in 

the county. Cretaceous rocks occur in the westernmost 

part of the county (Hose and others, 1976). 

Tertiary deposits consist of sedimentary and 

volcanic rocks. The volcanic rocks include ash-flow tuffs 

and lavas that range from rhyolite through andesite. 

Plutonic rocks are of Jurassic, Cretaceous, and 

Tertiary age and range from granite, through quartz 

monzonite, to granodiorite (Hose and others, 1976). 

The area was not exposed to any major tectonism 

during the Paleozoic Era, but two later major tectonic 

events took place in the county. The first event, during 

late Mesozoic to early Tertiary, consisted of high-angle 

normal faulting, thrust faulting, and folding. The second 

tectonic event took place during the Tertiary and 

Quaternary periods, reaching its climax in late Miocene 

(Hose and others, 1976) and consisted of high-angle 

faulting that resulted in elongated fault-block mountain 

ranges and basins that form the present topography. 

50 Index of Granitic Rock Masses in Nevada 

Geologic data were summarized from Hose and 

others (1976). 

Plutons 

WP-1. Southern Snake Range 

General location: North end of the southern Snake 

Range. 

Coordinates: lat 38°58' N., long 114°13' W. 

Land classification: Humboldt National Forest. 

Area: 84 km 2

• 

Accessibility: Northernmost major exposure is 3 km 

south of U.S. Highways 50 and 6. 

Composition: Quartz monzonite and granodiorite. 

Age: More than 50 radiometric age determinations 

ranging from 17 to 240 m.y., with most consistent 

determinations ranging from 156 to 160 Ma; the 

latest age determinations of 145±2.0 Ma, and 

170± Ma, lead-alpha, zircon (Marvin and Dobson, 

1979) (Jurassic). 

Rocks intruded: McCoy Creek Group of Misch and 

Hazzard (1962) (Precambrian-quartzite, schist, 

and pelitic rocks), Stella Lake Quartzite of Misch 

and Hazzard (1962) (Precambrian), Prospect 

Mountain Quartzite (Precambrian and Cambrian), 

Pioche Shale (Cambrian), and Cambrian limestone 

and shale. 

Aeromagnetic expression: 

Anomaly: High (long-wavelength, west flank). 

Inferred source: Unknown. 

Mining activity: Gold placer deposits have been found 

in the northwestern part of the range, and tungsten 

has been mined in the southeastern part of the 

range. 

Selected references: Hose and others, 1976; Lee and 

others, 1970; Marvin and Dobson, 1979; Misch and 

Hazzard, 1962. 

WP-2. Northern Snake Range 

General location: South end of the northern Snake 

Range. 

Coordinates: lat 39°15' N., long 114°12' W. 

Land classification: Humboldt National Forest. 

Area: 39 km2

• 

Accessibility: 9 km north of U.S. Highways 50 and 6. 

Composition: Quartz monzonite and granodiorite. 

Age: K-Ar determination on micas range from 17.0 to 

156 Ma (Lee and others, 1970) (Tertiary to 

Jurassic). 

Rocks intruded: Cambrian shale, limestone, and 

quartzite; Pogonip Group (Ordovian-limestone); 

Eureka Quartzite (Ordovician); Guilmette 
115o30' 115o00' ELKO COUNTY ,-----r---..=-(C)----r------

t

' --. (C) ( <6\vP-12 

( 

-r-wP-1 7 , J 

40°00' 't- _ _,/ ~--- (C) 

\ 

\ tJ W.f-16 

,~" 

\ ", ; 

/----, 

I WP-1 1 I 

I :-- (C) ( 1\J I 

Cherry Creek 1 ) .g' e-WP-15 

> ( i:i 

~) g, 

~I ~I 

wf 

I 

(M) 

WP-18-{"'\ 

I I ) 

I \'~!I 

v I 

~ ' ~ ' 

(M) 

WP-14 

~ 

;_.\.-."\ 

I ~ J \." / ) 

39°00''~ 

EXPLANATION '~, 

Cenozoic Plutons-C de-~ ' 

notes small outcrops 1\tr~ 

('~;--..... Cenozoic and (or) Meso- v4-~~ 

zoic Plutons r '"" 

-

Mesozoic Plutons-M. denotes small outcrops 10 

\" l) ) ,_./ 

20 30 KILOMETERS 

I 

I 

~ 

I 

I 

__ L ______ _j 

LINCOLN COUNTY 

'----'---~-·-___j 

• • Thrust fault-Sawteeth on 

upper plate 

Figure 14. Locations of plutons in White Pine County. 

Formation (Devonian-limestone); Sevy and 

Simonson Dolomites (Devonian-limestone); Pilot 

Shale (Devonian and Mississippian); Joana 

Limestone (Mississippian); and Chainman Shale 

(Mississippian). 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Lee and others, 1970. 

WP-3. Kern Mountains 

General location: Kern Mountains near Utah State 

line. 

Coordinates: lat 39°42' N., long 114°12' W. 

Land classification: Public domain, private land, and 

patented mining claims. 

Area: 107 km2

• 

Accessibility: 10 km southeast of State Highway 2. 

Composition: Granodiorite with some quartz monzonite and granite. 

Age: 23.3±0.6 Ma, K-Ar, biotite; 48.2± 1.0 Ma, K-Ar, 

muscovite; 72±7 Ma, Rb-Sr, whole rock (Hose and 

others, 1976) (Cretaceous and Tertiary). 

White Pine County 51 
Rocks intruded: Ordovician and Silurian sedimentary 

rocks, Sevy and Simonson Dolomites (Devonian), 

Pilot Shale (Devonian and Mississippian), Joana 

Limestone (Mississippian), Chainman Shale 

Mississippian), Ely Limestone (Pennsylvanian and 

Permian), and Riepe Spring Limestone of Stewart 

and Carlson (1978) (Pennsylvanian and Permian). 

Aeromagnetic expression: 

Anomaly: Low (long-wavelength, west-trending), 

perhaps coupled with a high to the south. 

Inferred source: Unknown. 

Mining activity: None. 

Selected references: Hose and others, 1976; Steele, 

1960. 

WP-4. Antelope Range 

General location: Central part of the Antelope Range. 

Coordinates: lat 39°53' N., long 114°27' W. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: 7 km northwest of State Highway 2. 

Composition: Quartz monzonite. 

Age: Tertiary. 

Rocks intruded: Ordovician and Silurian sedimentary 

rocks, Sevy and Simonson Dolomites (Devonian), 

Rib Hill Sandstone (Permian), and Arcturus 

Formation (Permian--limestone, sandstone, and 

siltstone). 

Aeromagnetic expression: 

Anomaly: Low. 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Hose and others, 1976. 

WP-5. Northern Schell Creek Range 

General location: Northern Schell Creek Range. 

Coordinates: lat 39°37' N., long 114°37' W. 

Land classification: Humboldt National Forest and 

private land. 

Area: 2 km2

• 

Accessibility: 8 km east of U.S. Highway 93, and 11 km 

east of Nevada Northern Railroad. 

Composition: Quartz monzonite. 

Age: Tertiary. 

Rocks intruded: Pogonip Group (Ordovician-limestone), Eureka Quartzite (Ordovician), Pilot Shale 

(Devonian and Mississippian), Joana Limestone 

(Mississippian), Chainman Shale (Mississippian), 

Ely and Riepe Spring Limestones (Pennsylvanian 

and Permian), and Park City Group (Permianlimestone and dolomite). 

Aeromagnetic expression: 

Anomaly: Highs and lows. 

Inferred source: Unknown. 

52 Index of Granitic Rock Masses in Nevada 

Mining activity: None. 

Selected reference: Hose and others, 1976. 

WP-6. Indian Creek 

General location: East flank of the central Schell Creek 

Range. 

Coordinates: lat 39°16' N., long 114°31' W. 

Land classification: Humboldt National Forest. 

Area: Less than 1 km2

• 

Accessibility: 23 km north of U.S. Highways 50 and 6, 

and 1 km west of an unnumbered paved road. 

Composition: Quartz monzonite. 

Age: Tertiary. 

Rocks intruded: McCoy Creek Group (Precambrianquartzite, schist, and pelitic rocks). 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, long-wavelength, 

west-trending). 

Inferred source: Granitic rocks having a maximum 

areal extent of about 100 km2

• 

Mining activity: None. 

Selected reference: Misch and Hazzard, 1962. 

WP-7. Southern Egan Range 

General location: East flank of the southern part of the 

Egan Range, near Ward Gulch. 

Coordinates: lat 39°05' N., long 114°52' W. 

Land classification: Public domain and private land. 

Area: 2 km2

• 

Accessibility: 9 km southwest of U.S. Highways 50 

and 6. 

Composition: Quartz monzonite. 

Age: 35.1±1.3 Ma, K-Ar, biotite (McKee and Marvin, 

1976) (Tertiary). 

Rocks intruded: Arcturus Formation (Permian-limestone, sandstone, and siltstone), Ely and Riepe 

Spring Limestones (Pennsylvanian and Permian). 

Aeromagnetic expression: 

Anomaly: Regional. 

Inferred source: Unknown. 

Mining activity: Lead and silver have been mined in 

vicinity of pluton. 

Selected reference: McKee and Marvin, 1976. 

WP-8. Saxton Peak 

General location: Egan Range. 

Coordinates: lat 39°16' N., long 11SOOO' W. 

Land classification: Patented mining claims. 

Area: 8 km2

• 

Accessibility: Outcrops occur on both north and south 

sides of U.S. Highway 50. Nevada Northern 

Railroad runs north and south of outcrops. 

Composition: Monzonite and quartz monzonite. 
Age: 109±1.5 Ma, K-Ar, hornblende (McDowell and 

Kulp, 1967); 115 ±3 Ma, fission track, sphene, 

zircon, and apatite (Hose and others, 1976) 

(Cretaceous). 

Rocks intruded: Guilmette Formation (Devonian), 

Pilot Shale (Devonian and Mississippian), Joana 

Limestone (Mississippian), Chainman Shale (Mississippian), Rib Hill Sandstone (Permian), Arcturus Formation (Permian-limestone, sandstone, 

and siltstone), and Ely and Riepe Spring 

Limestones (Pennsylvanian and Permian). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, steep north flank). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 10 km2

• 

Mining activity: Copper, gold, and silver have been 

mined. The granitic intrusives occur near the 

Ruth open-pit operation. 

Selected references: Brokaw, 1967; Hose and others, 

1976; McDowell and Kulp, 1967. 

WP-9. Heusser Mountain 

General location: Heusser Mountain, Egan Range. 

Coordinates: lat 39°29' N., long 114°52' W. 

Land classification: Public domain. 

Area: 3 km2

• 

Accessibility: 7 km west of U.S. Highway 93 and 3 km 

west of the Nevada Northern Railroad. 

Composition: Quartz monzonite. 

Age: 33.6±0.7 Ma, K-Ar, biotite (Armstrong, 1970a), 

and 30± 10 Ma, lead-alpha, zircon (Marvin and 

Dobson, 1979) (Tertiary). 

Rocks intruded: McCoy Creek Group (Precambrianquartzite, schist, and pelitic rocks). 

Aeromagnetic expression: 

Anomaly: High (west flank). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 50 km2

• 

Mining activity: None. 

Selected references: Armstrong, 1970a; Marvin and 

Dobson, 1979. 

WP-1 0. Northern Egan Range 

General location: East flank of the northern Egan 

Range. 

Coordinates: lat 39°38' N., long 114°52' W. 

Land classification: Public domain. 

Area: 25 km 2

• 

Accessibility: 8 km west of U.S. Highway 93 and 4 km 

west of Nevada Northern Railroad. 

Composition: Granite porphyry and quartz monzonite. 

Age: 36.2±0.7 Ma, K-Ar, no material indicated in 

reference (Armstrong, 1970a) (Tertiary). 

Rocks intruded: McCoy Creek Group (Precambrianquartzite, schist, and pelitic rocks), Silurian and 

Ordovician sedimentary rocks, Simonson and Sevy 

Dolomites (Devonian), Guilmette Formation 

(Devonian -limestone), Pilot Shale (Devonian and 

Mississippian), Joana Limestone (I\.1ississippian ), 

Chainman Shale (Mississippian), Rib Hill 

Sandstone (Permian), Arcturus Formation (Permian-limestone, sandstone, and siltstone), Ely 

and Riepe Spring Limestones (Pennsylvanian and 

Permian). 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, north-trending, 

north flank). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 25 km2

• 

Mining activity: None. 

Selected reference: Armstrong, 1970a. 

WP-11. Cherry Creek Range 

General location: North end of the Egan Range. 

Coordinates: lat 39°49' N., long 114°53' W. 

Land classification: Public domain, private land, and 

patented mining claims. 

Area: 16 km2

• 

Accessibility: 1 km west of the end of State Highway 35, 

14 km west of U.S. Highway 93, and 7 km west of 

the Nevada Northern Railroad. 

Composition: Quartz monzonite. 

Age: 40.3±4 Ma, fission track, sphene and zircon 

(Hose and others, 1976) (Tertiary). 

Rocks intruded: McCoy Creek Group (Precambrianquartzite, schist, and pelitic rocks); Cambrian, Silurian, and Ordovician sedimentary rocks; Pilot 

Shale (Devonian and Mississippian); Joana 

Limestone (Mississippian); and Chainman Shale 

(Mississippian). 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, long-wavelength). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 25 km2

• 

M:ining activity: None. 

Selected reference: Hose and others, 1976. 

W'P-12. Maverick Springs Range 

General location: East flank of the Maverick Springs 

Range. 

Coordinates: lat 40°05' N., long 11S016' W. 

Land classification: Public domain. 

Area: 6 km2

• 

Accessibility: 72 km north of U.S. Highway 50 and 3 km 

northwest of a dirt road. 

Composition: Quartz monzonite. 

Age: Tertiary. 

White Pine County 53 
Rocks intruded: Rib Hill Sandstone (Permian) and 

Park City Group (Permian -limestone and 

dolomite). 

Aeromagnetic expression: 

Anomaly: Short -wavelength, low-amplitude flexure. 

Inferred source: Exposed plutonic rocks. 

Mining activity: None. 

Selected reference: Hose and others, 1976. 

WP-13. Limestone Peak 

General location: West flank of Limestone Peak. 

Coordinates: lat 39°10' N., long 115°17' W. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: 22 km south of U.S. Highway 50 and 19 

km northwest of U.S. Highway 6. 

Composition: Quartz monzonite. 

Age: Tertiary. 

Rocks intruded: Surrounded by alluvium. 

Aeromagnetic expression: 

Anomaly: High (low-amplitude nose). 

Inferred source: Granitic rocks. 

Mining activity: None. 

Selected reference: Brokaw and others, 1973. 

WP-14. Mount Hamilton 

General location: West flank of Mount Hamilton, 

White Pine Range. 

Coordinates: lat 39°15' N., long 115°34' W. 

Land classification: Humboldt National Forest, private 

land, and patented mining claims. 

Area: 1 km2

• 

Accessibility: 16 km south of U.S. Highway 50. 

Composition: Quartz monzonite. 

Age: 90.4±2 Ma, K-Ar, biotite-chlorite (Armstrong, 

1970b); 128±1.5 Ma, lead-alpha, zircon (Marvin 

and Dobson, 1979) (Cretaceous). 

Rocks intruded: Cambrian limestone and shale. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength, 

circular, steep north flank). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 100 km2

• 

Mining activity: None. 

Selected references: Armstrong, 1970b; Marvin and 

Dobson, 1979. 

WP-15. Alligator Ridge 

General location: North end of Alligator Ridge. 

Coordinates: lat 39°50' N., long 115°29' W. 

Land classification: Public domain. 

Area: 1 km2

• 

54 Index of Granitic Rock Masses in Nevada 

Accessibility: 49 km north of U.S. Highway 50 and 8 km 

west of a dirt road. 

Composition: Quartz monzonite. 

Age: Tertiary. 

Rocks intruded: Devonian quartzite, dolomite, and 

limestone. Formerly included in the Nevada 

Formation of Hose and others, 1976 (now 

abandoned). 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Hose and others, 1976. 

WP-16. Little Bald Mountain 

General location: Little Bald Mountain. 

Coordinates: lat 39°57' N., long 115°33' W. 

Land classification: Public domain and patented 

mining claims. 

Area: 7 km2

• 

Accessibility: 59 km north of U.S. Highway 50. 

Composition: Granite and quartz monzonite. 

Age: Tertiary. 

Rocks intruded: Cambrian limestone and shale, 

Pogonip Group (Ordovician-limestone), Eureka 

Quartzite (Ordovician), Ordovician and Silurian 

sedimentary rocks, and Devonian sedimentary 

rocks formerly included in the Nevada Formation 

of Hose and others, 1976 (now abandoned). 

Aeromagnetic expression: 

Anomaly: Low (low-amplitude flexure). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Hose and others, 1976. 

WP-17. Northern Diamond Mountains 

General location: North end of the Diamond 

Mountains. 

Coordinates: lat 40°01' N., long 115°50' W. 

Land classification: Public domain. 

Area: Less than 1 km 2

• 

Accessibility: 71 km north of U.S. Highway 50 and 5 km 

east of State Highway 46 (Eureka County). 

Composition: Quartz monzonite. 

Age: 45 ± 10 Ma, lead-alpha, zircon (Marvin and 

Dobson, 1979) (Tertiary). 

Rocks intruded: Ely and Riepe Spring Limestones 

(Pennsylvanian and Permian). 

Aeromagnetic expression: 

Anomaly: Low (low-amplitude). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Marvin and Dobson, 1979. 
WP-18. Pancake Range 

General location: North end of the Pancake Range. 

Coordinates: lat 39°14' N., long 115°46' W. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: 15 km south of U.S. Highway 50. 

Composition: Granodiorite. 

Age: 108±3 Ma, K-Ar, biotite (Hose and others, 1976) 

(Cretaceous). 

Rocks intruded: Pilot Shale (Devonian and Mississippian), Joana Limestone (Mississippian), Chainman 

Shale (Mississippian), and Diamond Peak 

Formation (Mississippian-siltstone, claystone, 

and sandstone). 

Aeromagnetic expression: 

Anomaly: High (north-trending, southeast flank 

associated with plutonic rock). Low (lowamplitude, short -wavelength) centered over the 

main exposure. 

Inferred source: Granitic rocks. 

Mining activity: None. 

Selected references: Hose and others, 1976; Nolan and 

others, 1974. 

ELKO COUNTY 

Geology 

Elko County (fig. 15), in the northeast part of the 

State, lies in the Great Basin and has typical Basin and 

Range topography. The southern and western parts of 

the county are dominated by long, narrow ranges with 

north to northeast trends. In the northern part of the 

county the ranges exhibit a less definite trend. In the 

northwest, where the Basin and Range province borders 

the Columbia Plateaus province, the ranges are irregular 

in shape and are deeply dissected by canyons. 

Many of the exposed plutons within the county 

intrude thick Paleozoic sedimentary units. The Paleozoic 

rocks generally belong to two distinct facies: the western 

facies consists mainly of slate, chert, metamorphosed 

volcanic rock, and sandstone; the eastern carbonate 

facies consists of limestone, dolomite, and minor 

amounts of quartzite, conglomerate, and shale. Most of 

the Paleozoic formations have been intensely folded and 

broken by thrust and normal faults. At a few localities, 

intrusives penetrate Triassic sandstone, shale, and 

limestone; these sedimentary rocks represent outliers of 

rocks that arc more extensive in Utah. 

The plutons in this county range from Jurassic to 

Tertiary and arc commonly described as quartz monzonite or granodiorite. The granitic masses situated along 

the north border of the State have been described by 

previous workers as probably genetically related to the 

Idaho batholith. 

Much of the geologic information concerning 

granitic rocks in Elko County has been abstracted from 

Granger and others (1957). 

Plutons 

EL-1. Mountain City District 

General location: Mountain City. 

Coordinates: lat 41°51' N., long 11S056' W. 

Land classification: Northwestern exposures and the 

western part of the largest exposure are on the 

Duck Valley Indian Reservation. Eastern outcrops 

are on Humboldt National Forest lands. 

Area: 127 km2

• 

Accessibility: State Highway 51 crosses over the largest 

exposure in the Independence Range and is within 

16 km of the extreme northeast exposures. 

Composition: Granodiorite and quartz monzonite. 

Age: Range from 80 to 90 Ma, K-Ar, biotite (Coats and 

others, 1965); 70±20 and 110± 15 Ma, lead-alpha, 

zircon (Schilling, 1965) (Cretaceous; parts of the 

pluton could be Jurassic-Tertiary). 

Rocks intruded: Undifferentiated Antler orogenic 

sedimentary rocks that include Paleozoic volcanics, 

limestone, conglomerate, and phyllite. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, west -trending) 

associated with the main mass of plutonic rocks. 

Inferred source: Plutonic rocks that may extend 

westward in the subsurface for a distance of 30 km 

and that may have a maximum extent of 75 km 2

• 

M:ining activity: Silver has been mined near the two 

south exposures. 

Selected references: Coats, 1971; Coats and others, 

1965; Schilling, 1965. 

EL-2. Alder-Tennessee Mountain District 

(Bearpaw Mountain and Bruneau River) 

General location: East of Mountain City, near north 

county (and State) border. 

Coordinates: lat 41 °53' N., long 115°36' W. 

Land classification: Humboldt National Forest. 

Area: 136 km2

• 

Accessibility: The southernmost outcrop is 17 km 

northeast of State Highway 51. 

Composition: Granodiorite. 

Elko County 55 
Age: 73 Ma, K-Ar, biotite (Coats and others, 1965) 

(Cretaceous). 

Rocks intruded: Paleozoic eastern assemblage 

sediments (quartzite, siltstone, limestone, and 

dolomite) and Paleozoic transitional assemblage 

(phyllite, shale, and limestone). 

Aeromagnetic expression: 

Anomaly: Low (long-wavelength) associated with 

western two-thirds of north exposure. High 

(circular) associated with east third. Highs (highamplitude) associated with larger south exposure. 

Inferred source: Plutonic rocks having an areal 

extent about the same as that of the exposures. 

Mining activity: Tungsten, silver, and gold have been 

mined near the southwest margin of the main 

exposure. 

Selected reference: Coats and others, 1965. 

EL-3. Coleman Canyon 

General location: Northeast of Wild Horse. 

Coordinates: lat 41 °44' N., long 11S043' W. 

Land classification: Humboldt National Forest. 

Area: 3 km2

• 

Accessibility: State Highway 51 passes about 7.5 km 

southwest of the pluton. 

Composition: Diorite. 

Age: 152.1±5 Ma, K-Ar, biotite (Coats and McKee, 

1972) (Jurassic). 

Rocks intruded: Paleozoic slate, shale, and limestone. 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, short-wavelength, 

, elliptical). 

Inferred source: Plutonic rocks having the same 

areal extent as that of the exposures. 

Mining activity: Tungsten, silver, and gold have been 

mined directly north of the pluton. 

Selected reference: Coats and McKee, 1972. 

EL-4. White Elephant Butte (Elk Mountains) 

General location: Northeastern part of county. 

Coordinates: lat 41 °54' N., long 115°05' W. 

Land classification: Humboldt National Forest. 

Area: 10 km2

• 

Accessibility: U.S. Highway 93, extending northward 

from Wells, passes 29 km southeast of the 

exposure. 

Composition: Granodiorite. 

Age: 100± 10 Ma, lead alpha, zircon (Marvin and Cole, 

1978) (Cretaceous). 

Rocks intruded: Cambrian limestone and dolomite. 

Aeromagnetic expression: 

Anomaly: High (very high amplitude, elliptical). 

56 Index of Granitic Rock Masses in Nevada 

Inferred source: A plutonic body of 10 km 2 

maximum areal extent may underlie the 

southeastern part of the anomaly. 

Mining activity: None. 

Selected references: Coats and others, 1965; Marvin 

and Cole, 1978. 

EL-5. Contact District 

General location: Granite Range, northeastern part of 

county. 

Coordinates: lat 4J051' N., long 114°40' W. 

Land classification: Public domain, private land, and 

patented mining claims. 

Area: 161 km2

• 

Accessibility: The Union Pacific Railroad and U.S. 

Highway 93 pass between two major outcrops. 

Composition: Granodiorite. 

Age: 140±5 Ma, K-Ar, hornblende and 147±4 Ma, 

K-Ar, biotite (McDowell, 1971); 150 Ma, K-Ar, 

biotite (Coats and others, 1965) (Jurassic). 

Rocks intruded: Paleozoic limestone and shale. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength, 

west-trending). 

Inferred source: A plutonic rock body having a 

maximum areal extent of 50 km2 may underlie the 

eastern part of the anomaly. 

Mining activity: None. 

Selected references: Coats and others, 1965; 

McDowell, 1971. 

EL-6. Delano Peak 

General location: Northeastern part of county. 

Coordinates: lat 41°38' N., long 114°15' W. 

Land classification: Public domain and patented 

mining claims. 

Area: 5 km2

• 

Accessibility: U.S. Highway 93 and State Highway 30 

pass 45 km west and 37 km southeast of the 

outcrop, respectively. The Southern Pacific 

Railroad nearly parallels State Highway 30, and the 

Union Pacific Railroad nearly parallels U.S. 

Highway 93. 

Composition: Quartz monzonite and granodiorite. 

Age: 134.2±1.5 Ma, K-Ar, biotite; 136.0±2.0 Ma, 

K-Ar, biotite (Slack, 1974) (Cretaceous). 

Rocks intruded: Permian siltstone, sandstone, 

limestone, and dolomite. 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, long-wavelength). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Slack, 1974. 
m 

;: 

0 

(") 

0 

c 

:s 

~ 

Ul 

~ 

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r----- ------------

I 

I 

I 

I 

I 

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I 

410 L ______ _____ l (C) II® 

LANDER COUNTY ----r-EL-20 

EXPLANATION i ( Qt\ 

I

'-.._./ 

Cenozoic Plutons-C de- M 

notes small outcrops 1 E([_ 1 ~ 8 

Cenozoic and (or) Meso- S0 ··~ i~~ 

zoic Plutons-eM de- -"~~S 

notes small outcrops 

Mesozoic Plutons-M denotes small outcrops 

10 20 30 KILOMETERS 

I 

~\ c, 

i\ n, 

~\ 

~\ 

Figure 15. Locations of plutons in Elko County. 

(C) 

a EL-18 

, _ _., '%! (M) 

EL-3 

-----=-===-===1 

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---/ (M) 

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/--" 

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I 

'I 

I 

~ I 

I 

EL-14 X.,..--·\ 

I . ~ ~\ (@ ,~_, 

"'@' -.; '-..___./ 

<0 / (C M) !0:.""'-

\..c:,___/ EL-15 I 00 \ 

7-- .... \ 

(o /'V 

_________ '-- _ ___l ______ _ 

WHITE PINE COUNTY 

;::'\ 

(CM) 

Gl> EL-7 

I \ 

I 

I 

lc 

I.., 

l:l> 

(CM) ~:t EL-9 

!\'", 

l11 ' i ctor \ I 

\ \_../ o\ I 

I 

I 

I 

I 

/Ia A.·.EL-12 

\ lcr\ \ :; ---- (s-~~;~ riD } '------,. (C) I 

- ----43-E_!:-~- _j 
EL-7. Tony Mountain 

General location: Northeastern part of county, south of 

Tony Mountain. 

Coordinates: lat 41°29' N., long 114°27' W. 

Land classification: Public domain. 

Area: 5 km2

• 

Accessibility: The intrusive body is 24.5 km east of U.S. 

Highway 93 and 28.5 km east of the Union Pacific 

Railroad. The Southern Pacific Railroad passes 

about 30 km to the south, and State Highway 30 

traverses a mountain pass 44 km to the south. 

Composition: Granodiorite, quartz monozonite. 

Age: Jurassic-Tertiary(?). 

Rocks intruded: Permian limestone, dolomite, shale, 

and sandstone. 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Granger and others, 1957. 

EL-8. Silver Zone Pass 

General location: Northern Toana Range. 

Coordinates: lat 40°57' N., long 114°18' W. 

Land classification: Public domain and private land 

(railroad} 

Area: 16 km . 

Accessibility: The north exposure is 27 km southwest of 

Montello and 54.5 km southeast of Wells. The 

south exposure lies 27.5 km northwest of the 

border town of Wendover. 

Composition: Granodiorite. 

Age: 124±5 Ma, K-Ar, biotite (McDowell, 1971); 150 

Ma, K-Ar, biotite (Coats and others, 1965) 

(Jurassic and Cretaceous). 

Rocks intruded: Cambrian and Ordovician limestone, 

dolomite, quartzite, shale, and siltstone. 

Aeromagnetic expression: 

Anomaly: Low (low-amplitude, long-wavelength). 

Inferred source: Unknown. 

Mining activity: None. 

Selected references: Coats and others, 1965; 

McDowell, 1971. 

EL-9. Southern Pilot Range 

General location: Along the east border of the county 

at the Utah State line and north of Wendover. 

Coordinates: lat 40°54' N., long 114°06' W. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: The outcrops lie approximately 11 km 

northeast of U.S. Highway 40 and 13 km northeast 

of the Western Pacific Railroad. 

Composition: Granite. 

Age: Jurassic-Tertiary(?). 

58 Index of Granitic Rock Masses in Nevada 

Rocks intruded: Mississippian and Pennsylvanian 

limestone, dolomite, siltstone, and sandstone. 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Granger and others, 1957. 

EL-1 o. White Horse Flat 

General location: Extreme southeastern part of county. 

Coordinates: lat 40°16' N., long 114°16' W. 

Land classification: Public domain and patented 

mining claims. 

Area: 10 km2

• 

Accessibility: U.S. Highway Alternate 50 crosses 

Antelope Valley 5 km northwest of the west 

exposure. The Nevada Northern Railroad passes 

through Currie about 35 km west of the exposure. 

Composition: Quartz monzonite. 

Age: 140 ( + 21, -7) Ma, K-Ar, biotite (Schilling, 1965) 

(Jurassic; parts of pluton could be JurassicTertiary). 

Rocks intruded: Mississippian and Pennsylvanian 

limestone, dolomite, siltstone, and sandstone. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, elongate, northwesttrending). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 50 km2

• 

Mining activity: None. 

Selected references: Schilling, 1965; Armstrong, 1966. 

EL-11. Kingsley Mountains 

General location: Extreme southeastern part of county, 

south end of Kingsley Mountains. 

Coordinates: lat 40°07' N., long 114°21' W. 

Land classification: Public domain and patented 

mining claims. 

Area: 2 km2

• 

Accessibility: The exposure is 10 km southeast of U.S. 

Highway 50 Alternate and 31 km east of the 

Nevada Northern Railroad. 

Composition: Quartz monzonite. 

Age: 33.4±0.7 Ma, K-Ar, biotite (McKee and Marvin, 

1976); 35 Ma, K-Ar, biotite; and 40 Ma, lead-alpha, 

zircon (Schilling, 1965) (Tertiary). 

Rocks intruded: Cambrian dolomite and limestone. 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected references: McKee and Marvin, 1976; Schilling 

1965. 
EL-12. Dolly Varden Mountains 

General location: Southeastern part of county, 

northern Antelope Range. 

Coordinates: lat 40°211 N., long 114°32' W. 

Land classification: Public domain and mining claims. 

Area: 39 km2

• 

Accessibility: The main mass occurs 7 km southeast of 

the Nevada Northern Railroad, 15.5 km northeast 

of U.S. Highway 93, and 15 km northwest of U.S. 

Highway Alternate 50. 

Composition: Monzonite and syenite. 

Age: 125 ( + 19, -6) Ma, K-Ar, biotite-hornblende 

(Schilling, 1965) (Cretaceous; parts of pluton could 

be Jurassic-Tertiary). 

Rocks intruded: Permian limestone and shale. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength, 

northwest -trending). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 50 km2

• 

Mining activity: Copper has been mined. 

Selected reference: Schilling, 1965. 

EL-13. Currie 

General location: North of Currie, in southeastern part 

of county. 

Coordinates: lat 40~2 1 N., long 114°461 W. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: U.S. Highway 93 is 4 km west and the 

Nevada Northern Railroad passes 6 km east of the 

exposure. 

Composition: Granodiorite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Overlain by Tertiary volcanics. 

Aeromagnetic expression: 

Anomaly: West flank of high associated with the 

Dolly Varden pluton. 

Inferred source: Rocks of the Currie and Dolly 

Varden pluton may be connected at depth, despite 

observed contrasts of mineralogic and petrologic 

compositio_n. 

Mining activity: None. 

Selected reference: Granger and others, 1957. 

EL-14. Deicer Buttes 

General location: Northwest of Currie. 

Coordinates: lat 40°231 N ., long 115°03' W. 

Land classification: Public domain. 

Area: 37 km2

• 

Accessibility: The eastern exposures lie 11 km west of 

U.S. Highway 93, and the Nevada Northern 

Railroad passes through Currie 22 km southeast of 

the largest outcrop. 

Composition: Granodiorite and quartz monzonite. 

Age: 149 Ma, K-Ar, biotite (Armstrong and Suppe, 

1973) (Jurassic; parts of pluton could be JurassicTertiary). 

Rocks intruded: Permian limestone, dolomite, shale, 

and sandstone. 

Aeromagnetic expression: 

Anomaly: High (long-wavelength). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 150 km2

• 

Mining activity: None. 

Selected reference: Armstrong and Suppe, 1973. 

EL-15. Maverick Springs Range 

General location: Northern Maverick Springs Range. 

Coordinates: lat 40°15' N., long 11S015 1 W. 

Land classification: Public domain. 

Area: 5 km2

• 

Accessibility: U.S. Highway 93 is about 40 km 

northeast of central outcrop. 

Composition: Granodiorite, quartz monzonite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Permian limestone, dolomite, shale, 

siltstone, and sandstone. 

Aeromagnetic expression: None. 

Mining activity: None. 

Sellected reference: Granger and others, 1957. 

EL.-16. Southern Ruby Mountains 

General location: Southern Ruby Mountains. 

Coordinates: lat 40°231 N ., long 115°321 W. 

Land classification: Humboldt National Forest 

(northwest edge of body is designated as private 

land). 

Area: 253 km 2

• 

Accessibility: State Highway 46 is 5 km west of the 

exposure. 

Composition: Granite. 

Age: 26 to 30 Ma, K-Ar, biotite; 30 to 40 Ma, leadalpha, zircon (Schilling, 1965) (Tertiary; parts of 

the pluton could be Jurassic-Tertiary). 

Rocks intruded: Devonian limestone, sandstone, 

quartzite, and Mesozoic metasedimentary rocks. 

Aeromagnetic expression: None. 

Mining activity: None. 

, Selected references: Coats and others, 1965; Schilling, 

1965; Sharp, 1942. 

Elko County 59 
EL-17. East Humboldt 

General location: Southern East Humboldt Range. 

Coordinates: lat 40°41' N., long 115°06' W. 

Land classification: Humboldt National Forest, private 

land, and public domain. 

Area: 2 km2

• 

Accessibility: State Highway 11 passes within 5 km of 

the outcrops and connects with U.S. Highway 93 

about 5 km east of the area. 

Composition: Diorite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Permian siltstone, sandstone, 

limestone, and dolomite and Triassic siltstone and 

limestone. 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Granger and others, 1957. 

EL-18. Railroad Mining District 

General location: Southwest edge of county. 

Coordinates: lat 40°31' N., long 116°01' W. 

Land classification: Public domain, private land, and 

patented mining claims. 

Area: 2 km2

• 

Accessibility: The outcrop is about 28 km southwest of 

State Highway 51. 

Composition: Quartz monzonite. 

Age: 33 ( + 5, -2) Ma, K-Ar, biotite (Schilling, 1965); 

37.3±1.9 Ma, K-Ar, biotite (Marvin and Dobson, 

1979) (Tertiary). 

Rocks intruded: Paleozoic shale, siltstone, sandstone, 

limestone, quartzite, and conglomerate. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, equidimensional, 

steep north flank). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 15 km2

• 

Mining activity: None. 

Selected references: Schilling, 1965; Marvin and Dobson, 1979; Armstrong, 1966. 

EL-19. Adobe Range 

General location: West of Elko. 

Coordinates: lat 40°48' N., long 115°59' W. 

Land classification: Private land. 

Area: 2 km2

• 

Accessibility: The exposure lies 4 km northwest of U.S. 

Highway 40 (Interstate 80) and the Southern 

Pacific and Western Pacific Railroads. 

Composition: Granodiorite(?). 

Age: Jurassic-Tertiary. 

60 Index of Granitic Rock Masses in Nevada 

Rocks intruded: Pennsylvanian and Permian limestone, 

conglomerate, and siltstone and Devonian and 

Mississippian shale, siltstone, sandstone, and 

conglomerate. 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, circular). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 10 km2

• 

Mining activity: None. 

Selected reference: Granger and others, 1957. 

EL-20. Swales Mountain 

General location: Southernmost peak of the 

Independence Mountains. 

Coordinates: lat 40°56' N., long 116°03' W. 

Land classification: Public domain and private land. 

Area: 5 km2

• 

Accessibility: State Highway 11 (also called 51) passes 

12 km east, and U.S. Highway 40 (Interstate 80) is 

19 km southeast of the outcrops. 

Composition: Quartz monzonite and granodiorite with 

some diorite. 

Age: 38.3±1.3 Ma, K-Ar, biotite (Evans and Ketner, 

1971) (Tertiary). 

Rocks intruded: Vinini (Ordovician-chert and shale) 

and Roberts Mountains Formations (Silurian and 

Devonian -limestone). 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, circular). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 10 km2

• 

Mining activity: None. 

Selected reference: Evans and Ketner, 1971. 

EL-21. Nannie's Peak 

General location: Northwest of Elko at Lone 

Mountain. 

Coordinates: lat 41 °07' N., long 115°58' W. 

Land classification: Public domain and private land. 

Area: 8 km2

• 

Accessibility: The main mass occurs 7.5 km west of 

State Highway 11 (also called 51). 

Composition: Quartz monzonite. 

Age: 12 Ma, K-Ar, no mineral indicated in reference 

(Lovejoy, 1959) (Tertiary). 

Rocks intruded: McClellan Creek sequence (Devonian -limestone). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 15 km2

• 

Mining activity: None. 

Selected reference: Lovejoy, 1959. 
EL-22. Dry Creek Mountain 

General location: West of Tuscarora. 

Coordinates: lat 41 °19' N., long 116°20' W. 

Land classification: Public domain and private land. 

Area: 7 km2

• 

Accessibility: The east margin of the body lies about 8 

km west of State Highway 18 and 17.5 km westnorthwest of the intersection of Highway 18 and 

State Highway 11. 

Composition: Granodiorite. 

Age: 38.4± 1.5 Ma, K-Ar, biotite (McKee and Marvin, 

1976) (Tertiary). 

Rocks intruded: Ordovician chert, shale, quartzite, 

greenstone, limestone, and volcanic rock. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude). 

Inferred source: Granitic rocks having a maximum 

areal extent of about 75 km2

• 

Mining activity: None. 

Selected reference: McKee and Marvin, 1976. 

HUMBOLDT COUNTY 

Geology 

Humboldt County (fig. 16) is located in the 

northwestern part of the State. The southern and central 

parts of the county have topography typical of the Basin 

and Range province. The northeastern part of the county, 

a broad plateau underlain by volcanic rocks, is the 

southern extension of the Columbia Plateaus province. 

The northwestern part of the county is also a broad 

plateau that appears to be a transition zone between the 

Columbia Plateaus province on the north and the Basin 

and Range province on the south (Willden, 1964). 

Rocks of Cambrian, Ordovician, Mississippian, 

Pennsylvanian, Permian, Triassic, Jurassic(?), Cretaceous, and Tertiary ages are found in the county. 

The Cambrian, Ordovician, Mississippian, and 

Pennsylvanian rocks are in the southeastern part of the 

county and consist of clastic sedimentary rocks, with 

some carbonate and basic volcanic rocks. The Permian 

rocks consist of carbonate rocks, sandstone, chert, shale, 

conglomerate, and basic volcanic rocks (Willden, 1964). 

Triassic rocks are found in the central part of the county 

and consist of fine-grained clastic rocks and some 

quartzite and limestone. Cretaceous rocks that occur 

throughout the county consist of sandstone, siltstone, 

conglomerate, and granitic intrusives. Tertiary rocks 

consist of rhyolitic to dacitic welded tuff and lava flows. 

The regional structure of the county is not well 

known. Four periods of compressive deformation have 

affected the area (Willden, 1964), followed by normal 

faulting during the Tertiary. The Paleozoic rocks were 

folded and thrust faulted during the Antler orogeny 

(Late Devonian and Early Mississippian time) and again 

in Permian time. Triassic rocks were then folded and 

thrust faulted, followed by deformation of Cretaceous 

rocks in Late Cretaceous or early Tertiary time. Tertiary 

basin-and-range faults were superposed on the older 

structural complex. 

The Oregon-Nevada lineament, in the northeastern part of the county, consists of closely spaced, 

partly en echelon faults that extend from Oregon into 

Nevada. The segment of the lineament in Nevada is 

composed of closely spaced north-northwest-trending 

faults. 

The geologic data were summarized from Willden 

(1964). 

Plutons 

H-1. Disaster Peak 

General location: Northern part of the Trout Creek 

Mountains (Montana Mountains) near Disaster 

Peak. 

Coordinates: lat 41 °51' N., long 118°11' W. 

Land classification: Public domain. 

Area: 93 km 2

• 

Accessibility: 31 km east of State Highway 140 and 37 

km west of U.S. Highway 95. 

Composition: Granodiorite. 

Age: Cretaceous. 

Rocks intruded: Overlain by Tertiary volcanics. 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude, northwesttrending series). 

Inferred source: Plutonic rocks having a maximum 

areal extent about the same as that of exposure. 

Mining activity: None. 

Selected reference: Willden, 1964. 

H-2. Bilk Creek Mountains (Kings River Range) 

General location: Northern part of the Bilk Creek 

Mountains (Kings River Range). 

Coordinates: lat 41 °52' N., long 118°30' W. 

Land classification: Predominantly public domain. 

Area: 131 km2

• 

Humboldt County 61 
Accessibility: State Highway 140 borders the western 

outcrop. 

Composition: Granodiorite. 

Age: 90.6±3.2 Ma, K-Ar, biotite (Smith and others, 

1971) (Cretaceous). 

Rocks intruded: Overlain by Tertiary volcanic rocks. 

Aeromagnetic expression: 

Anomaly: Highs (short-wavelength). 

Inferred source: Basaltic flows and ash-flow tuff. 

Mining activity: None. 

Selected reference: Smith and others, 1971. 

H-3. Pueblo Mountains 

General location: East flank of the Pueblo Mountains. 

Coordinates: lat 41 °59' N., long 118°41' W. 

Land classification: Public domain and patented 

mining claims. 

Area: 4 km2

• 

Accessibility: 3 km north of State Highway 140. 

Composition: Quartz monzonite. 

Age: 92.4±1.3 Ma, K-Ar, biotite (Harrold, 1972) 

(Cretaceous). 

Rocks intruded: Permian and Triassic chlorite schist, 

hornfels, quartz-mica schist, and marble. 

Aeromagnetic expression: 

Anomaly: High (short-wavelength, doubly lobed). 

Inferred source: Composite extrusive and intrusive 

rocks. 

Mining activity: None. 

Selected reference: Harrold, 1972. 

H-4. Duffer Peak 

General location: Duffer Peak, Pine Forest Range. 

Coordinates: lat 4J040' N., long 118°45' W. 

Land classification: Public domain and private land. 

Area: 364 km 2

• 

Accessibility: Northernmost outcrop is 1 km south of 

State Highway 140, southernmost outcrop is 26 km 

west of State Highway 140. 

Composition: Granodiorite and quartz diorite. 

Age: 93.6±1.5 Ma, 101±2.0 Ma, and 107±2.1 Ma, 

K-Ar, biotite-quartz diorite (Harrold, 1972); 

160±2.0 Ma, lead-alpha, zircon-granodiorite 

(Marvin and Dobson, 1979) (Jurassic and 

Cretaceous). 

Rocks intruded: Happy Creek Volcanic Complex 

(Triassic? and Jurassic) and Triassic and Jurassic 

limestone, phyllite, slate, and quartzite. 

Aeromagnetic expression: 

Anomaly: Highs and lows arranged in a complex 

pattern. 

Inferred source: The highest amplitude anomalies 

are associated with diorite; lower amplitude 

anomalies are associated with granodiorite. 

62 Index of Granitic Rock Masses in Nevada 

Mining activity: None. 

Selected references: Harrold, 1972; Marvin and 

Dobson, 1979. 

H-5. Santa Rosa Peak 

General location: Santa Rosa Peak, central part of the 

Santa Rosa Range. 

Coordinates: lat 41°32' N., long 117°38' W. 

Land classification: Predominantly Humboldt National 

Forest and private land. 

Area: 133 km2

• 

Accessibility: Main outcrop is 6 km east of U.S 

Highway 95, and 5 km west of State Highway 8B. 

Composition: Granodiorite. 

Age: 97.8±3 Ma, K-Ar, biotite; 99.5±5 Ma, K-Ar, 

biotite (Silberman and McKee, 1971) 

(Cretaceous). 

Rocks intruded: Grass Valley Formation (Triassicshale, quartzite, and limestone), Winnemucca 

Formation (Triassic-shale, slate, carbonate rocks, 

sandstone, and quartzite), and Raspberry 

Formation (Triassic-phyllite, limestone, and 

quartzite). 

Aeromagnetic expression: 

Anomaly: Highs and lows, complexly distributed. 

Inferred source: Plutonic rocks. 

Mining activity: Tungsten has been mined in southern 

part of the Santa Rosa Range. 

Selected reference: Silberman and McKee, 1971. 

H-6. Osgood Mountain Stock 

General location: Northern part of the Osgood 

Mountains at Adam Peak. 

Coordinates: lat 41°10' N., long 117°15' W. 

Land classification: Private land and public domain. 

Area: 19 km2

• 

Accessibility: 32 km east of U.S Highway 95 and 7 km 

north of State Highway 18. 

Composition: Granodiorite. 

Age: 88.3±1.8 Ma, K-Ar, biotite; 89.9±1.8 Ma, K-Ar, 

hornblende; 92± 1.8 Ma, K-Ar, biotite (Silberman 

and McKee, 1971) (Cretaceous). 

Rocks intruded: Preble Formation (Cambrian-shale, 

limestone, and quartzite). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, elliptical, northtrending). 

Inferred source: Pluton having maximum areal 

extent of about 5 km2

• 

Mining activity: None. 

Selected references: Silberman and McKee, 1971; 

Silberman and others, 1974. 
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---·"...:..:.-_· _______ _ RAILR(}_AD _ i~£/ RAILROAD f1H-1 ll ~§ I~ PERSHING COUNTY - ------1 I j / 5 

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EXPLANATION 

Thrust fault-Sawteeth on 

upper plate '---; r----' 

v 

Figure 16. Locations of plutons in Humboldt County. 
H-7. Bloody Run Hills 

General location: Bloody Run Hills, southern part of 

the Santa Rosa Range. 

Coordinates: lat 41 °10' N., long 117°44' W. 

Land classification: Private land and public domain. 

Area: 37 km2

• 

Accessibility: 2 km west of U.S. Highway 95. 

Composition: Granodiorite. 

Age: Cretaceous. 

Rocks intruded: Singas Formation (Triassic-phyllite, 

limestone, and quartzite). 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude, oval). 

Inferred source: Plutonic rocks having maximum 

areal extents about the same as those of exposures. 

Mining activity: None. 

Selected reference: Willden, 1964. 

H-8. Slumbering Hills 

General location: Central part of the Slumbering Hills. 

Coordinates: lat 41 °13' N., long 118°00' W. 

Land classification: Public domain and private land. 

Area: 76 km2

• 

Accessibility: 23 km west of U.S. Highway 95. 

Composition: Granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Triassic and Jurassic phyllite, slate, 

and quartzite. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength, 

west-trending). 

Inferred source: Plutonic rocks that appear to extend 

westward 20 km and southward 10 km; may be 

connected to Jungo Hills pluton of H-14, 25 km to 

the southwest; maximum areal extent of subsurface 

plutonic rocks is about 200 to 300 km2

• 

Mining activity: Gold has been mined just north of 

pluton. 

Selected reference: Willden, 1964. 

H-9. Northern Jackson Mountains 

General location: Northern part of the Jackson 

Mountains. 

Coordinates: lat 41 °22' N., long 118°28' W. 

Land classification: Public domain, private land, and 

patented mining claims. 

Area: 32 km2

• 

Accessibility: Northern outcrop 9 km southwest of 

State Highway 140, southern outcrop 22 km 

southwest of State Highway 140. 

Composition: Granodiorite and diorite. 

Age: 170±2.0 Ma, lead-alpha, zircon (Marvin and 

Dobson, 1979) (Jurassic). 

64 Index of Granitic Rock Masses in Nevada 

Rocks intruded: Permian and Triassic volcanic and 

sedimentary rocks, Happy Creek Volcanic complex 

(Triassic? and Jurassic), and King Lear Formation 

(Cretaceous- conglomerate, siltstone, graywacke, 

and limestone). 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude, northeasttrending). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 35 km2

• 

Mining activity: None. 

Selected reference: Marvin and Dobson, 1979. 

H-1 o. Battle Creek 

General location: East flank of the northern part of the 

Black Rock Range. 

Coordinates: lat 41 °26' N., long 118°53' W. 

Land classification: Public domain and private land. 

Area: 34 km2

• 

Accessibility: 40 km southwest of State Highway 140. 

Composition: Granodiorite. 

Age: 96.3±3.5 Ma, K-Ar, biotite (Smith and others, 

1971) (Cretaceous). 

Rocks intruded: Overlain by Tertiary volcanic rocks. 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude). 

Inferred source: Intrusive and extrusive rocks. 

Mining activity: None. 

Selected reference: Smith and others, 1971. 

H-11. Pahute Peak 

General location: Within the Black Rock Range. 

Coordinates: lat 41°17' N., long 119°07' W. 

Land classification: Public domain. 

Area: 5 km2

• 

Accessibility: 24 km northeast of State Highway 34 

(Washoe County). 

Composition: Granodiorite. 

Age: 170±20 m.y., lead-alpha, ztrcon (Marvin and 

Dobson, 1979) (Jurassic). 

Rocks intruded: Overlain by Tertiary volcanic and 

sedimentary rock. 

Aeromagnetic expression: 

Anomaly: High (high-amplified, long-wavelength, 

northwest -trending). 

Inferred source: Extrusive and intrusive rocks. 

Mining activity: None. 

Selected reference: Marvin and Dobson, 1979. 
H-12. Donnelly Peak 

General location: Calico Mountains. 

Coordinates: lat 41 °06' N., long 119°16' W .. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: 8 km east of State Highway 34 (Washoe 

County). 

Composition: Granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Triassic and Jurassic phyllite, slate, 

and quartzite. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, short-wavelength, 

elliptical). 

Inferred source: Plutonic rocks having a maximum 

areal extent of from 1 to 5 km2

• 

Mining activity: None. 

Selected reference: Willden, 1964. 

H-13. Navajo Peak 

General location: Southern part of the Jackson 

Mountains at Navajo Peak. 

Coordinates: lat 41 °08' N., long 118°32' W. 

Land classification: Public domain and private land. 

Area: 38 km2

• 

Accessibility: 22 km north of State Highway 49, and 18 

km north of Western Pacific Railroad. 

Composition: Granodiorite, diorite, and some syenite. 

Age: Cretaceous(?). 

Rocks intruded: Permian and Triassic volcanic and 

sedimentary rocks, Happy Creek Volcanic complex 

(Triassic? and Jurassic), and King Lear Formation 

(Cretaceous-conglomerate, siltstone, graywacke, 

and limestone). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude). 

Inferred source: Plutonic rocks having an areal 

extent about the same as that of exposures. 

Mining activity: Gold has been mined near pluton. 

Selected reference: Willden, 1964. 

H-14. Jungo Hills 

General location: Jungo Hills, southwest of Desert 

Valley. 

Coordinates: lat 41 °04' N., long 118°22' W. 

Land classification: Public domain and private land. 

Area: 3 km2

• 

Accessibility: Southern outcrop is 13 km north of State 

Highway 49 and Western Pacific Railroad. 

Composition: Granodiorite and diorite. 

Age: Jurassic and Cretaceous. 

Rocks intruded: Permian and Triassic volcanic and 

sedimentary rocks and Happy Creek Volcanic 

Complex (Triassic? and Jurassic). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength) 

that noses southwestward from high of Slumbering 

Hills pluton (H-8). 

Inferred source: Plutonic rocks; maximum areal 

extent associated with steepest gradients is about 

15 km2

• 

Mining activity: None. 

Selected reference: Willden, 1964. 

H-15. Blue Mountain 

General location: Southwest flank of Blue Mountain. 

Coordinates: lat 40°59' N., long 118°03' W. 

Land classification: Private land and public domain. 

Area: 3 km2

• 

Accessibility: 2 km north of State Highway 49 and 4 km 

north of Western Pac:ific Railroad. 

Composition: Diorite. 

Age: Jurassic and Cretaceous. 

Rocks intruded: Triassic and Jurassic phyllite, slate, 

and quartzite. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northwest-trending). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 10 km2

• 

Mining activity: None. 

Selected reference: Willd1en, 1964. 

H-16. Winnemucca Mountain 

General location: Southeast flank of Winnemucca 

Mountain, approximately 4 km northwest of 

Winnemucca. 

Coordinates: lat 41 °00' N., long 117°44' W. 

Land classsification: Private land and public domain. 

Area: 1 km2

• 

Accessibility: 2 km west of Interstate Highway 95, 2 km 

northwest of State Highway 49, and 4 km northwest 

of Western Pacific and Southern Pacific Railroads. 

Composition: Diorite. 

Age: Jurassic and Cretaceous. 

Rocks intruded: Winnemucca Formation (Triassicshale, sandstone, limestone, and quartzite). 

Aeromagnetic expression: 

Anomaly: High (low-amplitude, nose). 

Inferred source: Unknown. 

Mining activity: None. 

Selected reference: Willden, 1964. 

Humboldt County 65 
H-17. Edna Mountain 

General location: Northwest of Pumpernickel Valley. 

Coordinates: lat 40°49' N., long 117°24' N. 

Land classification: Public domain and private land. 

Area: 5 km2

• 

Accessibility: Main outcrop is 8 km southwest of U.S. 

Highway 40 and 12 km south of Southern Pacific 

Railroad. 

Composition: Granodiorite. 

Age: 101 Ma, K-Ar, biotite; 106 Ma, K-Ar, biotite and 

hornblende; and 104 Ma, K-Ar, muscovite 

(Erickson and others, 1978)(Cretaceous). 

Rocks intruded: Edna Mountain Formation (Permiansandstone and quartzite), Pumpernickel Formation 

(Pennsylvanian and Permian-chert, siltstone, and 

pyroclastics), and Antler Peak Limestone (Pennsylvanian and Permian). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, short-wavelength, 

oval). 

Inferred source: Plutonic rocks having maximum 

areal extent of about 5 km2

• 

Mining activity: None. 

Selected reference: Erickson and others, 1978. 

H-18. Buffalo Mountain 

General location: Southeast of Pumpernickel Valley. 

Coordinates: lat 40°43' N., long 117°21' W. 

Land classification: Public domain. 

Area: 38 km 2

• 

Accessibility: 14 km southwest of U.S. Highway 40 and 

the Southern Pacific Railroad. 

Composition: Granodiorite. 

Age: 145±3 Ma, K-Ar, hornblende; 151±3 Ma, K-Ar, 

biotite; 153±3 Ma, K-Ar, biotite; and 157±3 Ma, 

K-Ar, biotite (Silberman and McKee, 1971) 

(Jurassic). 

Rocks intruded: Pumpernickel Formation (Pennsylvanian and Permian-chert, siltstone, and pyroclastics), Havallah Formation (Pennsylvanian and Permian-sandstone, shale, quartzite, and limestone), 

Cane Spring Formation (Triassic-limestone and 

dolomite), and Augusta Mountain Formation (Triassic-limestone and dolomite). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, chevron-shaped). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 10 km2

• 

Mining activity: None. 

66 Index of Granitic Rock Masses in Nevada 

Selected reference: Silberman and McKee, 1971. 

H-19. Gregg Canyon 

General location: East flank of the Sonoma Range. 

Coordinates: lat 40°43' N., long 117°32' W. 

Land classification: Private land and public domain. 

Area: 13 km2

• 

Accessibility: Northernmost outcrop is 17 km 

southwest of U.S Highway 40 and 18 km southeast 

of Southern Pacific Railroad. 

Composition: Granodiorite. 

Age: 104±2 Ma, K-Ar, biotite (Silberman and McKee, 

1971) (Cretaceous). 

Rocks intruded: Osgood Mountain Quartzite (Cambrian?), Preble Formation (Cambrian-shale, 

limestone, and quartzite), Valmy Formation 

(Ordovician-shale, quartzite, and greenstone), 

Pumpernickel Formation (Pennsylvanian and Permian-chert, siltstone, and pyroclastics), and 

Havallah Formation (Pennsylvanian and Permiansandstone, shale, quartzite, and limestone). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northwest-trending). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 15 km2

• 

Mining activity: None. 

Selected reference: Silberman and McKee, 1971. 

PERSHING COUNTY 

Geology 

Pershing County (fig. 17) is located in the 

northwestern part of the State. The county is 

characterized by north-northeast-trending mountain 

ranges separated by narrow valleys. 

The county is underlain by sedimentary, metamorphic, and igneous rocks of Cambrian to Holocene age. 

The Cambrian, Ordovician, Mississippian, Pennsylvanian, and Permian rocks are found in the eastern part of 

the county. They consist predominantly of clastic 

sedimentary, some carbonate, and minor volcanic rocks. 

Triassic and Jurassic rocks are found throughout the 

county and consist of clastic sedimentary rocks, some 

carbonate and volcanic rocks, granodiorite, leucogranite, 

and quartz monzonite intrusives. 

The Cretaceous rocks are granodiorite and quartz 

monzonite intrusives. No sedimentary rocks of 

Cretaceous age are present in the county. Tertiary rocks 

in the county consist of tuff, lava flows, breccia of 
., 

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WESTERN PACIFIC RAILROAD 

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HUMBOLDT COUNTY 118° -------rr--.....,--- /~------r 

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EXPLANATION 

Cenozoic Plutons 

Cenozoic and (or) Mesozoic Plutons 

Mesozoic Plutons- M denotes small outcrops 

P-17'{\/@~ .® \ ____ _ "-' / '/ -------, I ---......... l@i!Jb '\ 

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CHURCHILL COUNTY 

0 10 20 30 KILOMETERS 

Figure 17. Locations of plutons in Pershing County. 
rhyolitic, andesitic, and basaltic composition, and 

sedimentary rocks. Basaltic flows of Tertiary and 

Quaternary age are also present. 

The area has undergone four major periods of 

deformation that caused folding, thrusting, and highangle normal faulting (Johnson, 1977). The periods of 

deformation are: (1) Antler orogeny of Late Devonian 

and Early Mississippian age, (2) Sonoma orogeny of Late 

Permian and Early Triassic age, (3) Nevadan orogeny of 

Jurassic and Cretaceous age, and ( 4) basin and range 

deformation of Tertiary and Quaternary age. 

The geologic information was summarized from 

Johnson (1977) and Tatlock (1969). 

Plutons 

P-1. Nightingale-Shawave 

General location: Nightingale and Shawave Mountains, 

southwestern part of the county. 

Coordinates: lat 40°10' N., long 119°07' W. 

Land classification: Public domain, with some private 

lands. 

Area: 402 km 2

• 

Accessibility: Westernmost exposure is 7 km east of 

State Highway 34 (Washoe County). The northern 

part of the major exposure is 4 km south of State 

Highway 48. 

Composition: Granodiorite. 

Age: 90.2±6.1 Ma, K-Ar, biotite and 91.3±3.8 Ma, 

K-Ar, hornblende (Smith and others, 1971) 

(Cretaceous). 

Rocks intruded: Triassic and Jurassic shale, mudstone, 

siltstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: Highs. 

Inferred source: Northwest extension of highs at the 

north margin of the exposures may be underlain by 

plutonic rocks having a maximum areal extent of 

about 50 km2

• 

Mining activity: None. 

Selected references: Tatlock, 1969; Smith and others, 

1971. 

P-2. Selenite 

General location: Selenite Range, western part of the 

county. 

Coordinates: lat 40°30' N., long 119°15' W. 

Land Classification: Public domain and private land. 

Area: 193 km2

• 

68 Index of Granitic Rock Masses in Nevada 

Accessibility: 6 km east of State Highway 34 and 0.5 km 

south of the Western Pacific Railroad tracks. State 

Highway 48 intersects the northern and central part 

of the exposed pluton. 

Composition: Granodiorite. 

Age: 91.2±3.1 Ma, K-Ar, biotite; 93.9±6 Ma, K-Ar, 

hornblende (Smith and others, 1971) (Cretaceous). 

Rocks intruded: Permian volcanic and sedimentary 

rocks and Triassic and Jurassic shale, mudstone, 

siltstone, sandstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: Highs (north-trending belt). 

Inferred source: Plutonic rocks having areal extent 

about the same as that of exposures. 

Mining activity: Gypsum has been mined on the west 

flank and in central part of the Selenite Range. 

Selected reference: Smith and others, 1971. 

P-3. Heineke 

General location: Pahsupp Mountain area. 

Coordinates: lat 40°35' N ., long 119°00' W. 

Land classification: Public domain. 

Area: 198 km2

• 

Accessibility: 0.5 km south of Western Pacific 

Railroad, and northern exposure intersected by 

State Highway 49. 

Composition: Granodiorite. 

Age: Cretaceous. 

Rocks intruded: Permian volcanic and sedimentary 

rocks and Triassic and Jurassic shale, mudstone, 

siltstone, sandstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength). 

Inferred source: Plutonic rocks probably connected 

to Selenite pluton (P-2); maximum areal extent is 

about 75 to 100 km2

• 

Mining activity: None. 

Selected references: Johnson, 1977; Tatlock, 1969. 

P-4. Seven Troughs 

General location: Seven Troughs Range, western half 

of the county. 

Coordinates: lat 40°33' N., long 118°48' W. 

Land classification: Public domain and patented 

mining claims. 

Area: 67 km2

• 

Accessibility: Central exposure is 11 km northwest of 

State Highway 48. 

Composition: Granodiorite with some leucogranite. 

Age: Cretaceous. 
Rocks intruded: Triassic and Jurassic shale, mudstone, 

siltstone, sandstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude). 

Inferred source: Plutonic rocks having a maximum 

areal extent of from 200 to 300 km2 • 

Mining activity: Gold and silver have been mined along 

east flank of mountain range. 

Selected references: Johnson, 1977; Tatlock, 1969. 

P-5. Trinity Range 

General location: Trinity Range, central and southcentral parts of the county. 

Coordinates: lat 40°24' N., long 118°30' W. 

Land classification: Public domain, private land, and 

Bureau of Reclamation withdrawals. 

Area: 150 km2 • 

Accessibility: Main outcrop is 13 km west of U.S. 

Highways 95 and 40 and the Southern Pacific 

Railroad, and 12 km northeast of State Highway 48. 

Composition: Granodiorite. 

Age: 89.6±5.9 Ma, K-Ar, hornblende (Smith and 

others, 1971) (Cretaceous). 

Rocks intruded: Triassic and Jurassic shale, mudstone, 

sandstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 150 km2

• 

Mining activity: Gold, diatomite, and lightweight 

aggregate and perlite have been mined along the 

Trinity Range. 

Selected reference: Smith and others, 1971. 

P-6. Haystack Butte 

General location: Antelope Range and Majuba 

Mountain area. 

Coordinates: lat 40°46' N., long 118°26' W. 

Land classification: Public domain and private land. 

Area: 26 km2 • 

Accessibility: Main outcrop is 22 km northwest of U.S. 

Highways 95, 80, and 40; 21 km northwest of 

Southern Pacific Radilroad; and 3 km north of 

State Highway 49. 

Composition: Granodiorite. 

Age: 92.0±3.9 Ma, K-Ar, hornblende; and 95.2±6.3 

Ma, K-Ar, hornblende (Smith and others, 1971) 

(Cretaceous). 

Rocks intruded: Triassic and Jurassic shale, mudstone, 

siltstone, sandstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude) associated with 

northern exposure. High (low-amplitude) associated with southern exposure. 

Inferred source: The subsurface plutonic rocks of 

the northern exposure may be about 25 km2 in 

areal extent. 

Mining activity: Gold has been mined in the south end 

of Majuba Mountain near pluton. 

Selected reference: Smith and others, 1971. 

P-7. Eugene Mountains 

General location: Eugene Mountains, north-central 

part of the county near Humboldt County line. 

Coordinates: lat 40°42' N., long 118°14' W. 

Land classification: Public domain and private land. 

Area: 10 km2

• 

Accessibility: Southwesternmost outcrop is 6 km 

northwest of Southern Pacific Railroad and 7 km 

northwest of U.S. Highways 95, 80, and 40. State 

Highway 49 intersects main outcrop. 

Composition: Granodiorite. 

Age: 90.0±2.7 Ma, K-Ar, biotite (Krueger and Schilling, 1971). Ages range from 66.5 to 88.9 Ma, 

(Tingley, 1975) (Cretaceous). 

Rocks intruded: Triassic and Jurassic shale, mudstone, 

siltstone, sandstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude). 

Inferred source: Plutonic rocks having a cumulative 

areal extent of about 35 km2

• 

Mining activity: Tungsten has been mined in the central 

and southwestern part of the Eugene Mountains 

near the pluton. 

Selected references: Krueger and Schilling, 1971; 

Tingley, 1975. 

P-8. Humboldt Range 

General location: Scattered outcrops throughout the 

Humboldt Range. 

Coordinates: lat 40°16' N., long 118°08' W. 

Land classification: Public domain, private land, and 

patented mining claims. 

Area: 20 km 2

• 

Accessibility: Southern exposures, 18 km east of U.S. 

Highways 95, 80, and 40 and 19 km east of the 

Southern Pacific Railroad; northern exposures, 5 

km east of U.S. Highways 95, 80, and 40 and 6 km 

east of the Southern Pacific Railroad. 

Composition: Leucogranite. 

Age: Triassic. 

Rocks intruded: Koipato Group (Triassic-volcanic 

rocks) and Triassic limestone, dolomite, shale, 

sandstone, and conglomerate. 

Pershing County 69 
Aeromagnetic expression: 

Anomaly: Highs (high-amplitude) in regional northtrending belt. 

Inferred source: Plutonic rocks having a cumulative 

areal extent as great as 250 to 300 km2

• 

Mining activity: Gold has been mined in the 

southwestern part of the Humboldt Range. 

Selected references: Johnson, 1977; Tatlock, 1969. 

P-9. Rocky Canyon Stock 

General location: West flank of the Humboldt Range. 

Coordinates: lat 40°24' N., long 118°13' W. 

Land classification: Public domain and private land. 

Area: 8 km2

• 

Accessibility: 3 km east of the Southern Pacific 

Railroad and U.S. Highways 95, 80, and 40 and 8 

km southeast of Rye Patch Reservoir. 

Composition: Granodiorite. 

Age: 73.1±3 Ma, K-Ar, biotite, and 125±15 Ma, leadalpha, zircon (Marvin and Dobson, 1979) 

(Cretaceous). 

Rocks intruded: Koipato Group (Triassic-volcanic 

rocks) and Triassic limestone, dolomite, shale, and 

sandstone. 

Aeromagnetic expression: 

Anomaly: High. 

Inferred source: Plutonic rocks that appear to be 

connected in the subsurface to the Humboldt 

Range pluton (P-8). 

Mining activity: None. 

Selected reference: Marvin and Dobson, 1979. 

P-1 o. West Humboldt 

General location: West flank of the southern part of the 

West Humboldt Range. 

Coordinates: lat 40°04' N., long 118°25' W. 

Land classification: Public domain and private land. 

Area: 9 km2

• 

Accessibility: 6 km southeast of State Highway 59. 

Composition: Granodiorite. 

Age: 104±4 Ma, K-Ar, biotite (Smith and others, 

1971) (Cretaceous). 

Rocks intruded: Triassic and Jurassic shale, mudstone, 

siltstone, sandstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: High (low-amplitude flexure). 

Inferred source: Plutonic rocks that may be 

connected to the Trinity Range pluton (P-5). 

Mining activity: None. 

Selected reference: Smith and others, 1971. 

P-11. New York Canyon 

General location: West flank of the Stillwater Range. 

Coordinates: lat 40°03' N., long 118°01' W. 

70 Index of Granitic Rock Masses in Nevada 

Land classification: Public domain. 

Area: 4 km2

• 

Accessibility: 38 km southeast of U.S. Highways 95, 80, 

and 40 and the Southern Pacific Railroad; 5 km 

south of an improved-surface road. 

Composition: Quartz monzonite. 

Age: 69±3 Ma, K-Ar, biotite (Speed and Armstrong, 

1971) (Cretaceous). 

Rocks intruded: Triassic and Jurassic shale, mudstone, 

siltstone, sandstone, and carbonates. 

Aeromagnetic expression: None. 

Mining activity: Clay has been mined in the 

northwestern part of the Stillwater Range. 

Selected reference: Speed and Armstrong, 1971. 

P-12. Stillwater 

General location: East flank of the Stillwater Range. 

Coordinates: lat 40°04' N., long 117°49' W. 

Land classification: Public domain. 

Area: 2 km2

• 

Accessibility: 52 km southeast of U.S. Highways 95, 80, 

and 40 and the Southern Pacific Railroad; 4 km 

west of an improved-surface road. 

Composition: Leucogranite. 

Age: Triassic. 

Rocks intruded: Koipato Group. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northeast-trending). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 50 km2

• 

Mining activity: None. 

Selected references: Johnson, 1977; Tatlock, 1969. 

P-13. Granite Mountain Stock 

General location: Southern part of the East Range at 

Granite Mountain. 

Coordinates: lat 40°17' N., long 117°49' W. 

Land classification: Public domain, private land, 

patented mmmg claims, and Bureau of 

Reclamation withdrawals. 

Area: 78 km2

• 

Accessibility: 37 km east of U.S. Highways 95, 80, and 

40 and the Southern Pacific Railroad; 5 km west of 

an improved-surface road. A major improvedsurface road also intersects the pluton. 

Composition: Leucogranite and quartz monzonite. 

Age: 29±1 and 30.3±2.6 Ma, K-Ar, biotite-quartz 

monzonite; 30± 10 Ma, lead-alpha, zircon-quartz 

monzonite; and 180±30 Ma, lead-alpha, 

hornblende-leucogranite (Marvin and Dobson, 

1979) (Jurassic and Tertiary). 
Rocks intruded: Quartz monzonite intrudes the older 

leucogranite, Pumpernickel Formation (Pennsylvanian and Permian-chert, siltstone, and pyroclastics) and Havallah Formation (Pennsylvanian and 

Permian-sandstone, shale, quartzite, and 

limestone), and Koipato Group (Triassic-volcanic 

rocks). The leucogranite intrudes the Pumpernickel and Havallah Formations; Koipato Group; 

and shale, mudstone, sandstone, and carbonate of 

Triassic and Jurassic age. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, west-trending, elliptical). 

Inferred source: Plutonic rocks having an areal 

extent about the same as that of exposures. 

Mining activity: None. 

Selected reference: Marvin and Dobson, 1979. 

P-14. Home Creek 

General location: East flank of the East Range. 

Coordinates: lat 40°31' N., long 117°40' W. 

Land classification: Public domain. 

Area: 6 km2

• 

Accessibility: 32 km east of State Highway 50 and 2 km 

west of an improved-surface road. 

Composition: Leucogranite. 

Age: Triassic. 

Rocks intruded: Pumpernickel Formation (Pennsylvanian and Permian -chert, siltstone, and pyroclastics) and Havallah Formation (Pennsylvanian and 

Permian-sandstone, shale, quartzite, and limestone). 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected references: Johnson, 1977; Tatlock, 1969. 

P-15. Lee Peak Stock 

General location: Central part of the East Humboldt 

Range at Lee Peak. 

Coordinates: lat 40°35' N., long 117°52' W. 

Land classification: Public domain and private land. 

Area: 17 km2

• 

Accessibility: Easternmost part of the main outcrop is 

13 km east of State Highway 50; 18 km southeast of 

U.S. Highways 95, 80, and 40; and 15 km west of an 

improved-surface road. 

Composition: Quartz monzonite. 

Age: 131±3 Ma, K-Ar, biotite; and 149±3 Ma, K-Ar, 

hornblende (Silberman and McKee, 1971) 

(Jurassic and Cretaceous). 

Rocks intruded: Harmony Formation (Cambrian/ 

sandstone, shale, limestone, and chert); Ordovician 

volcanic rocks; Pumpernickel Formation (Pennsylvanian and Permian -chert, siltstone, and 

pyroclastics); Havallah Formation (Pennsylvanian 

and Permian -limestone, sandstone, shale, and 

quartzite); Triassic limestone, shale, and 

sandstone; and Triassic and Jurassic shale, mudstone, siltstone, sandstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northwest-trending). 

Inferred source: About 15 km north of exposures 

and having a maximum areal extent of about 50 

km2

• 

Mining activity: None. 

Selected reference: Silberman and McKee, 1971. 

P-16. Dun Glen Peak 

General location: Northern part of the East Range, 

near Dun Glen Peak. 

Coordinates: lat 40°51' N., long 117°53' W. 

Land classification: Public domain and private land. 

Area: 1 km2

• 

Accessibility: 5 km east of Interstate Highway 80 and 6 

km east of Southern Pacific Railroad. 

Composition: Granite. 

Age: Cretaceous. 

Rocks intruded: Triassic and Jurassic shale, mudstone, 

siltstone, sandstone, and carbonate. 

Aeromagnetic expression: 

Anomaly: High (elongate). 

Inferred source: Plutonic rocks that may extend in 

subsurface northward from the Lee Peak pluton 

(P-15). 

Mining activity: Gold has been mined in the northern 

part of the East Range. 

Selected references: Johnson, 1977; Tatlock, 1969. 

P-17. Grand Trunk Canyon 

General location: West flank of the Sonoma Range. 

Coordinates: lat 40°41' N., long 117°38' W. 

Land classification: Public domain and private land. 

Area: 10 km2

• 

Accessibility: Main outcrop is 4 km east of an 

improved-surface road and 35 km east of Interstate 

Highway 80. 

Composition: Granite. 

Age: Jurassic-Tertiary. 

Rocks intruded: Pumpernickel Formation (Pennsylvanian and Permian-chert, siltstone, and pyroclastics) and Havallah Formation (Pennsylvanian and 

Permian-sandstone, shale, quartzite, and limestone). 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Johnson, 1977, Tatlock, 1969. 

Pershing County 71 
P-18. Tobin 

General location: Three exposures-one at the central 

part of the Tobin Range; the second exposure near 

Needle Peak, Tobin Range; and the third at Fish 

Creek Mountain. 

Coordinates: Northernmost exposure at lat 40°28' N., 

long 117°30' W. 

Land classification: Public domain. 

Area: 5 km2

• 

Accessibility: 48 km east of State Highway 50 and 8 km 

east of an improved-surface road. 

Composition: Granite. 

Age: 153±3 Ma, K-Ar, biotite (Silberman and McKee, 

1971) (Jurassic). 

Rocks intruded: Pumpernickel Formation (Pennsylvanian and Permian-chert, siltstone, and pyroclastics) and Havallah Formation (Pennsylvanian and 

Permian-sandstone, shale, quartzite, and limestone). 

Aeromagnetic expression: 

Anomaly: High (short-wavelength, elliptical). 

Inferred source: Plutonic rocks having a maximum 

areal extent of about 1 km2

• 

Mining activity: None. 

Selected reference: Silberman and McKee, 1971. 

WASHOE, STOREY, AND 

DOUGLAS COUNTIES AND 

CARSON CITY (INDEPENDENT CITY) 

Geology 

Washoe, Storey, and Douglas Counties and Carson 

City (independent city, formerly Ormsby County; fig. 18) 

are located along the northwest border of the State of 

Nevada. The three counties and Carson City have been 

grouped mainly because they are all situated along a 

transition zone between the Sierra Nevada and the Basin 

and Range provinces. Also, a few granitic exposures of 

batholithic dimensions, in adjoining counties, extend into 

these three counties. An example is the Carson Range, 

where a continuous granite mass is exposed in three 

counties. 

Igneous, metamorphic, and sedimentary rocks, 

ranging in age from Permian(?) to Quaternary, are 

exposed within the area. The oldest rocks consist of 

metamorphosed volcanic and sedimentary strata that 

have been intruded by bodies of granitic rocks of late 

Mesozoic age. The Mesozoic metasediments commonly 

consist of slate, phyllite, metatuff, argillite, quartzite, 

recrystallized limestone, and hornfels. Metavolcanics 

include regionally and thermally metamorphosed lava 

72 Index of Granitic Rock Masses in Nevada 

flows, breccia, and pyroclastics ranging from basalt to 

rhyolite in composition. Extensive areas throughout the 

counties are covered by Tertiary rocks, chiefly basaltic, 

andesitic, and rhyolitic lava flows, breccia, and pyroclastics with intercalated lenses of sedimentary rocks. 

Granodiorite and quartz monzonite are the most 

abundant types of granitic rocks, although alaskite and 

granite porphyry are also present. Several quartz monzonite and granodiorite intrusions of Miocene and (or) 

Pliocene age are present in southern Washoe and Storey 

Counties. These Tertiary plutons commonly exhibit weak 

to intense hydrothermal alteration. 

Geologic evidence indicates two main deformational episodes. The first episode began in late Mesozoic 

time and the second commenced in the late Tertiary, and 

continued into the Quaternary. Late Mesozoic structure 

is represented by folds, faults, and low-grade regional 

metamorphism prior to intrusion of granitic plutons in 

the Cretaceous(?) Period. 

A late period of deformation probably began in the 

middle to late Tertiary and has continued into the 

Quaternary. Structural features associated with this 

episode include normal faults, strike-slip displacement, 

and folds related to strike-slip movement. The Walker 

Lane fault zone is the dominant Cenozoic structural 

element in Washoe and Storey Counties, although 

movement along it may have begun in Early Jurassic 

time. This zone of strike-slip faults extends northwestward through Washoe County from the vicinity of Wadsworth to Honey Lake Valley near Flanigan. The latest 

detectable displacement along the fault occurred in the 

late Pleistocene (Bonham, 1969). 

Most of the geologic data summarized herein have 

been abstracted from Bonham (1969) and Moore (1969). 

Plutons 

WS-1. Granite Range 

General location: North of Gerlach. 

Coordinates: lat 40°46' N., long 119°23' W. 

Land classification: Public and private land. 

Area: 154 km 2

• 

Accessibility: State Highways 81 and 34 pass along the 

west and east flanks of the range, respectively. 

Highway 34 extends southward and connects with 

Interstate 80. The Western Pacific Railroad passes 

along the south margin. 

Composition: Granodiorite. 

Age: 88.8 Ma, K-Ar, biotite (Krueger and Schilling, 

1971) and 91.9±6.1 Ma, K-Ar, biotite (Smith and 

others, 1971) (Cretaceous). 
OREGON --------, 

WASHOE COUNTY 

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......... 

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40o WS-3 ' \ 

t----..::: _ __..J 

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EXPLANATION 

Cenozoic Plutons-C. denotes small outcrops 

Mesozoic Plutons 

10 20 30 KILOMETERS 

~--~-----_J _____ j 

® 

Figure 18. Locations of plutons in Washoe, Storey, and Douglas Counties and Carson City (independent city). A, north 

half of map area; 8, south half of map area. 

Washoe, Storey, and Douglas Counties and Carson City 73 
Rocks intruded: Permian(?) and Triassic lava flows, 

pyroclastics, metabasalt, metaandesite flows, and 

limestone. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, long-wavelength). 

Inferred source: Pluton; an additional plutonic rock 

mass, having a maximum areal extent of about 50 

km2

, is inferred to occur northeast of the mapped 

pluton. 

Mining activity: None. 

Selected references: Krueger and Schilling, 1971; 

Smith and others, 1971. 

WS-2. Fox Range 

General location: Southwest of Gerlach. 

Coordinates: lat 40°34' N., long 119°33' W. 

Land classification: Public domain. The southernmost 

exposure is on the Pyramid Lake Indian 

Reservation. 

Area: 79 km2

• 

Accessibility: State Highway 34 passes 13 km east of 

the westernmost exposure. The Western Pacific 

Railroad passes along the west flank of the range 

within 4 km of the western outcrops and adjacent to 

the northernmost exposure. 

Composition: Granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Nightingale sequence (Triassic and 

Jurassic-slate, phyllite, hornfels, limestone, and 

dolomite). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude) associated with 

, northernmost exposure. 

Inferred source: Unknown. 

Mining activity: None. 

Selected references: Bonham, 1969; Moore, 1969. 

WS-3. Fort Sage Mountains 

General location: West of Pyramid Lake, along California State line. 

Coordinates: lat 40°01' N., long 119°57' W. 

Land classification: Public domain and private land. 

Area: 31 km2

• 

Accessibility: The main exposure is 30 km northwest of 

State Highway 33 and 10 km south of the Western 

Pacific Railroad. 

Composition: Granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Overlain by Pyramid sequence (Tertiary-volcanics) and Santigo Canyon Tuff 

(Tertiary). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, northwest-trending). 

74 Index of Granitic Rock Masses in Nevada 

Inferred source: Intrusive and extrusive rocks. 

Mining activity: None. 

Selected reference: Gianella, 1957. 

WS-4. Nightingale District (Truckee Range) 

General location: East of Pyramid Lake (includes 

isolated exposure along the east shoreline of 

Pyramid Lake). 

Coordinates: lat 39°56' N., long 119°16' W. 

Land classification: Public domain and private land. 

Westernmost outcrop lies on the Pyramid Lake 

Indian Reservation. 

Area: 12 km2

• 

Accessibility: State Highway 34 is 7.5 km west of the 

main eastern exposure and the Southern Pacific 

Railroad is 15 km southwest of the southern 

outcrop. 

Composition: Granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Nightingale sequence (Triassic and 

Jurassic-slate, phyllite, hornfels, limestone, and 

dolomite). 

Aeromagnetic expression: 

Anomaly: High (short-wavelength) associated with 

northern exposures. 

Inferred source: Intrusive and extrusive rocks. 

Mining activity: None. 

Selected references: Bonham, 1969; Moore, 1969. 

WS-5. Stateline Peak District 

General location: North of Reno, along the NevadaCalifornia border. 

Coordinates: lat 39°40' N., long 119°52' W. 

Land classification: Public domain and private land. 

Area: 341 km2

• 

Accessibility: State Highway 33 extends along the east 

edges of three exposures. An abandoned branch of 

the Southern Pacific Railroad passes about 14 km 

northeast of the northeastern exposure. U.S. 

Highway 40 (Interstate 80) and a branch of the 

Southern Pacific Railroad pass along the southern 

outcrops. 

Composition: Granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Overlain by Santiago Canyon Tuff 

(Tertiary). 

Aeromagnetic expression: 

Anomaly: Highs (high-amplitude, northwest-trending). 

Inferred source: Unknown. 

Mining activity: None. 

Selected references: Bonham, 1969; Moore, 1969. 
WS-6. Pah Rah Range 

General location: South of Pyramid Lake. 

Coordinates: lat 39°44' N., long 119°34' W. 

Land classification: Private land and Pyramid Lake 

Indian Reservation. 

Area: 44 km 2

• 

Accessibility: State Highway 33 extends along the west 

edge of the exposures, and an abandoned branch of 

the Southern Pacific Railroad passes along the 

northeast edge of the northernmost outcrop. U.S. 

Highway 40 (Interstate Highway 80) passes 17 km 

south of the southernmost exposure. 

Composition: Granodiorite and quartz monzonite. 

Age: Cretaceous(?)-Tertiary. 

Rocks intruded: Lava flows, breccia, and pyroclastic 

rocks of Tertiary(?) age. 

Aeromagnetic expression: 

Anomaly: Highs. 

Inferred source: Extrusive and intrusive rocks. 

Mining activity: None. 

Selected reference: Carlson and others, 1975. 

WS-7. Olinghouse District 

General location: Northeast of Reno. 

Coordinates: lat 39°42' N., long 119°24' W. 

Land classification: Public domain, private land, and a 

few local mining claims. 

Area: 6 km2

• 

Accessibility: The largest outcrop occurs 2.5 km west of 

State Highway 34 and 3 km west of an abandoned 

branch of the Southern Pacific Railroad. U.S. 

Highway 40 (Interstate Highway 80) lies 10 km to 

the south. 

Composition: Granodiorite. 

Age: Tertiary. 

Rocks intruded: Santiago Canyon Tuff and Chloropagus Formation of Axelrod (1956). 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected reference: Axelrod, 1956. 

WS-8. Peavine District 

General location: West of Reno, along the California 

State boundary. 

Coordinates: lat 39°34' N., long 119°55' W. 

Land classification: Private land. 

Area: 29 km2

• 

Accessibility: U.S. Highway 40 (Interstate 80) passes 

along the south edge of the larger exposures and 

U.S. Highway 395 (alternate U.S. Highway 40) 

passes 5 km north of the northernmost exposures. 

Composition: Granodiorite. 

Age: Cretaceous(?)-Tertiary. 

Rocks intruded: Peavine sequence (Triassic and Jurassic-metavolcanic and metasedimentary rocks); 

Tertiary granodiorite intrudes older, Cretaceous(?) 

granodiorite. 

Aeromagnetic expression: 

Anomaly: High (short -wavelength, elliptical, 

northwest-trending). 

Inferred source: Diverse magnetic lithologies. 

Mining activity: None. 

Selected references: Bonham, 1969; Moore, 1969. 

WS-9. Carson Bange 

General location:: North and east of Lake Tahoe. 

Coordinates: lat 39°10' N., long 119°53' W. 

Land classification: Private land, national forest, and 

State lands. 

Area: 453 km2

• 

Accessibility: U.S. Highway 395 extends southward 

from Reno along the east edge of the Carson range 

and State Highway 28 passes along the east edge of 

Lake Tahoe. 

Composition: Granodiorite and quartz monzonite. 

Age: 77.7±1.0 Ma, K-Ar, biotite-granodiorite (Marvin 

and Cole, 1978) (Cretaceous). 

Rocks intruded: Triassic metasedimentary and metavolcanic rocks. 

Aeromagnetic expression: 

Anomaly: Highs (north-trending). 

Inferred source: Plutonic rocks. 

Mining activity: None. 

Selected references: Thompson and White, 1964; Garside, 1974; Marvin and Cole, 1978; Evernden and 

Kistler, 1970. 

D-1. Pine Nut Mountains 

General location: Northeastern part of Douglas 

County. 

Coordinates: la1t 38°59' N., long 119°27' W. 

Land classification: Public domain, private land, and 

Indian Trust Allotments. 

Area: 310 km2

• 

Accessibility: The northwestern outcrops are within 5 

km of U.S. Highway 50. West-central exposures are 

10-15 km east of U.S. Highway 395. The southern 

extent of the mountains is less than 1 km north of 

State Highway 3. 

Composition: Quartz monzonite. 

Washoe, Storey, and Douglas Counties and Carson City 75 
Age: 81 Ma, K-Ar, biotite, and 106 Ma, K-Ar, hornblende (Noble and others, 1973); 146 Ma, K-Ar, 

hornblende (Krueger and Schilling, 1971); and 145 

Ma, K-Ar, biotite and 180 Ma, K-Ar, hornblende 

(Caster and McKee, 1975) (Jurassic and 

Cretaceous). 

Rocks intruded: Triassic and Jurassic shale, slate, tuffaceous sandstone, sandstone, graywacke, andesitic 

tuff, and lava flows. 

Aeromagnetic expression: 

Anomaly: Highs (northwest-trending). 

Inferred source: Unknown. 

Mining activity: Gold has been mined along the 

southeast flank of the Pine Nut mountains. 

Selected references: Krueger and Schilling, 1971; Noble 

and others, 1973; Caster and McKee, 1975. 

D-2. Dresslerville 

General location: Western part of Douglas County 

near the Nevada-California State border. 

Coordinates: lat 38°52' N., long 119°44' W. 

Land classification: Private land and Bureau of 

Reclamation withdrawals. 

Area: 6 km2

• 

Accessibility: U.S. Highway 395 passes 3.5 km 

northeast and State Highway 88 is 2 km west of the 

exposure. 

Composition: Quartz monzonite and granodiorite. 

Age: Cretaceous. 

Rocks intruded: Triassic and Jurassic andesite breccia, 

tuff, basalt, and rhyolitic lava flows. 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, short-wavelength). 

Inferred source: Granitic rocks; that part within 

Nevada is inferred to have a maximum areal extent 

of from 1 to 5 km2

• 

Mining activity: None. 

Selected references: Bonham, 1969; Moore, 1969. 

D-3. Northern Sweetwater Mountains 

General location: Southeastern part of Douglas County 

along Nevada-California border. 

Coordinates: lat 38°34' N., long 119°21' W. 

Land classification: Toiyabe National Forest. 

Area: 42 km2

• 

Accessibility: U.S. Highway 395 passes within 9 km of 

the Nevada segment of the plutonic mass. State 

Highway 22, in Lyon County, passes along the 

eastern slope of the northern Sweetwater 

Mountains, about 8 km east of the exposures. 

Composition: Granodiorite and quartz monzonite. 

Age: Jurassic and Cretaceous. 

Rocks intruded: Triassic and Jurassic metasedimentary 

and metavolcanic rocks. 

76 Index of Granitic Rock Masses in Nevada 

Aeromagnetic expression: None. 

Mining activity: None. 

Selected references: Bonham, 1969; Moore 1969. 

S-1. Comstock Lode 

General location: West of Virginia City. 

Coordinates: lat 39°18' N., long 119°39' W. 

Land classification: Private land, public domain, and 

patented mining claims. 

Area: 1 km2

• 

Accessibility: The outcrop is about 1 km southwest of 

State Highway 45. 

Composition: Granite. 

Age: 15 Ma, K-Ar, plagioclase (Carlson and others, 

1975) (Tertiary). 

Rocks intruded: Alta Formation (Tertiary-volcanics). 

Aeromagnetic expression: None. 

Mining activity: Lightweight aggregate and perlite have 

been mined along the west flank of the Virginia 

Range. 

Selected references: Thompson, 1956; Carlson and 

others, 1975. 

S-2. Flowery Range (Virginia Range) 

General location: Southeast part of Storey County. 

Coordinates: lat 39°21' N., long 119°30' W. 

Land classification: Private land, public domain, and 

patented mining claims. 

Area: 15 km2

• 

Accessibility: U.S. Highway 50 crosses the southernmost outcrop in Lyon County. State Highway 79 

passes 4 km southwest of the westernmost outcrop. 

Composition: Granodiorite. 

Age: Cretaceous(?). 

Rocks intruded: Peavine sequence (Triassic and Jurassic-slate, phyllite, argillite, quartzite, greywacke, 

and limestone). 

Aeromagnetic expression: 

Anomaly: High (high-amplitude, short-wavelength, 

north-trending). 

Inferred source: Plutonic rocks having a maximum 

areal extent of from 1 to 5 km2

• 

Mining activities: Gold has been mined approximately 

4 km south of the westernmost exposure. 

Lightweight aggregate and perlite have also been 

mined within the area. 

Selected references: Bonham, 1969; Moore, 1969. 
SELECTED REFERENCES 

Albers, J.P., 1967, Belt of sigmoidal bending and right-lateral 

faulting in the western Great Basin: Geological Society of 

America Bulletin, v. 78, no. 2, p. 143-155. 

Albers, J.P., and Stewart, J.H., 1972, Geology and mineral 

deposits of Esmeralda County, Nevada: Nevada Bureau 

of Mines and Geology Bulletin 78, 80 p. 

Anderson, R.E., 1969, Notes on the geology and paleohydrology of the Boulder City pluton, southern Nevada, 

in Geological Survey research 1969: U.S. Geological 

Survey Professional Paper 650-B, p. B35-B40. 

___ 1973, Large-magnitude late Tertiary strike-slip faulting 

north of Lake Mead, Nevada: U.S. Geological Survey 

Professional Paper 794, 18 p. 

Andreasen, G.E., and Zietz, Isidore, 1969, Magnetic fields for 

a 4x6 prismatic model: U.S. Geological Survey 

Professional Paper 666, 9 p. 

Armstrong, R.L., 1966, K-Ar dating using neutron activation 

for Ar analysis: Geochimica et Cosmochimica Acta, v. 30, 

no. 6, p. 565-600. 

___ 1968, Sevier orogenic belt in Nevada and Utah: 

Geological Society of America Bulletin, v. 79, p. 

429-458. 

___ 1970a, Geochronology of Tertiary igneous rocks, 

eastern Basin and Range province, western Utah, eastern 

Nevada, and vicinity, U.S.A.: Geochimica et Cosmochimica Acta, v. 34, no. 2, p. 203-232. 

___ 1970b, K-Ar dating using neutron activation for Ar 

analysis-Comparison with isotope dilation Ar analyses: 

Geochimica et Cosmochimica Acta, v. 34, no. 2, p. 

233-236. 

Armstrong, R.L., and Suppe, John, 1973, Potassium-argon 

geochronometry of Mesozoic igneous rocks in Nevada, 

Utah, and southern California: Geological Society of 

America Bulletin, v. 84, p. 1375-1392. 

Ashley, R.P., and Silberman, M.L., 1976, Direct dating of 

mineralization at Goldfield, Nevada, by potassium-argon 

and fission-track methods: Economic Geology, v. 71, no. 

5, p. 904-924. 

Axelrod, D.l., 1956, Mio-Pliocene floras from west-central 

Nevada: California University Publications in Geological 

Sciences, v. 33, p. 138-139. 

Bath, G.D., 1976, Intrepretation of magnetic surveys in intermontane valleys of Nevada and southern New Mexico: 

U.S. Geological Survey Open-File Report 76-440, 47 p. 

Bath, G.D., Jahren, C.E., Rosenbaum, J.G., and Baldwin, M.J., 

1983, Magnetic investigations, in Geologic and Geophysical Investigations of the Climax Stock intrusive, Nevada: 

U.S. Geological Survey Open-File Report 83-377, p. 

40-77. 

Barnes, Harley, Christiansen, R.L., and Byers, F.M., Jr., 1965, 

Geologic map of the Jangle Ridge Quadrangle, Nye and 

Lincoln Counties, Nevada: U.S. Geological Survey 

Geologic Quadrangle Map GQ-363, scale 1:24,000. 

Bingler, E.C., and Bonham, H.F., Jr., 1973, Reconnaissance 

geologic map of McCullough Range and adjacent areas, 

Clark County, Nevada: Nevada Bureau of Mines and 

Geology Map 45, scale 1:125,000. 

Bingler, E.C., Silberman, M.L., and McKee, E.H., 1980, K-Ar 

ages of volcanic and plutonic rocks in the northern 

Wassuck Range, central-western Nevada: Isochron/ 

West; no. 27, p. 13-16. 

Blake, D.W. Theodore, T.G., Batchelder, J.N., and Kretschmer, 

E.L., 1979, Structural relations of igneous rocks and 

mineralization in the Battle Mountain mining district, 

Lander County, Nevada, in Ridge, J.D., ed., Papers on 

mineral deposits of western North America: Nevada 

Bureau of Mines and Geology Report 33, p. 87-99. 

Blakely, R.J., 1986, Mapping the depth to the Currietemperature isotherm with aeromagnetic data from 

Nevada [ abs.]: Transactions of the American Geophysical Union, v. 64, no. 44, p. 920. 

Bonham H.F., 1969, Geology and mineral deposits of Washoe 

and Storey Counties, Nevada: Nevada Bureau of Mines 

Bulletin 70, 140 p. 

___ 1970, Geologic map and sections of a part of the 

Shoshone Mountains, Lander and Nye Counties: Nevada 

Bureau of Mines Map 38, scale 1:62,500. 

Bonham, H.F., Jr., and Garside, L.J., 1979, Geology of the 

Tonopah, Lone Mountain, Klondike, and northern Mud 

Lake quadrangles, Nevada: Nevada Bureau of Mines and 

Geology Bulletin 92, 142 p. 

Brokaw, A.L., 1967, Geologic map and sections of the Ely 

quadrangle, White Pine County, Nevada: U.S. 

Geological Survey Geologic Quadrangle Map GQ-697, 

scale 1:24,000. 

Brokaw, A.L., Bauer, H.L., and Breitrick, R.A., 1973, Geologic 

map of the Ruth quadrangle, White Pine County, 

Nevada: U.S. Geological Survey Geologic Quadrangle 

Map GQ-1085, scale 1:24,000. 

Byers, F.M., Jr., Carr, W.J., Orkild, P.P., Quinlivan, W.D., and 

Sargent, K.A., 1976, Volcanic suites and related 

cauldrons of Timber Mountain-Oasis Valley caldera 

complex, southern Nevada: U.S. Geological Survey 

Professional Paper 919, 69 p. 

Callaghan, Eugene, 1939, Geology of the Searchlight mining 

district, Clark County, Nevada: U.S. Geological Survey 

Bulletin 906-D, p. 135-188. 

Callaghan, Eugene, and Gianella, V.P., 1935, The earthquake 

of January 30, 1934, at Excelsior Mountains, Nevada: 

Seismological Society of America Bulletin, v. 25, p. 

161-168. 

Carlson, J.E., Laird, D.W., Peterson, J.A., Schilling, J.H., 

Silberman, M.L., and Stewart, J.H., 1975, Preliminary 

map showing distribution and isotopic ages of Mesozoic 

and Cenozoic intrusive rocks in Nevada: U.S. Geological 

Survey Open-File Report 75-499, scale 1:1,000,000. 

Carr, W.J., and Quinlivan, W.D., 1966, Geologic map of the 

Timber Mountain Quadrangle, Nye County, Nevada: 

U.S. Geological Survey Geologic Quadrangle Map 

GQ-503, scale 1:24,000. 

Caster, S., and McKee, E.H., 1975, Mesozoic intrusions, Pine 

Nut and Buckskin Ranges, western Nevada: Geological 

Society of America Abstracts with Programs, v. 7, no. 3, 

p. 303. 

Cebull, S.E., 1967, Bedrock geology of the southern Grant 

Range, Nye County, Nevada: Seattle, Wash., Washington 

University Ph. D. thesis, 130 p. 

Selected References 77 
Christiansen, R.L., and Noble, D.C., 1965, Black Mountain 

volcanism of Southern Nevada [abs.]: Geological Society 

of America Special Paper 82, p. 246. 

Coats, R.R., 1968, Preliminary geologic map of the 

southwestern part of the Mountain City quadrangle, Elko 

County, Nevada: U.S. Geological Survey Open-File Map, 

scale 1:20,000. 

___ 1971, Geologic map of the Owyhee quadrangle, 

Nevada-Idaho: U.S. Geological Survey Miscellaneous 

Geologic Investigations Map I-665, scale 1:48,000. 

Coats, R.R., and MacKenzie, Gordon, Jr., 1972, Tectonic 

implications of the presence of the Edna Mountain 

Formation in northern Elko County, Nevada: U.S. 

Geological Survey Professional Paper 800-C, p. 

C85-C94. 

Coats, R.R., Marvin, R.F., and Stern, T.W., 1965, 

Reconnaissance of mineral ages of plutons in Elko 

County, Nevada, and vicinity, in Geological Survey 

research 1965: U.S. Geological Survey Professional 

Paper 525-D, p. 011-015. 

Coats, R.R., and McKee, E.H., 1972, Ages of plutons and types 

of mineralization, northwestern Elko County, Nevada, in 

Geological Survey research 1972: U.S. Geological Survey 

Professional Paper 800-C, p. C165-C168. 

Cornwall, H.R., 1972, Geology and mineral deposits of 

southern Nye County, Nevada: Nevada Bureau of Mines 

and Geology Bulletin 77, 49 p. 

Crowder, D.F., McKee, E.H., Ross, D.C., and Krauskopf, K.B., 

1973, Granitic rocks of the White Mountains area, 

California-Nevada-Age and regional significance: 

Geological Society of America Bulletin, v. 84, no. 1, p. 

285-296. 

Edwards, George, and McLauglin, W.A., 1972, Shell list No. 

1-K/Ar and Rb/Sr age determinations of California, 

Nevada, and Utah rocks and minerals: Isochron/West, 

no. 3, p. 1-7. 

Ekren, E.B., Anderson, R.E., Rogers, C.L., and Noble, D.C., 

1971, Geology of northern Nellis Air Force Base 

Bombing and Gunnery Range, Nye County, Nevada: U.S. 

Geological Survey Professional Paper 651, 91 p. 

Ekren, E.B., Bucknam, R.C., Carr, W.J., Dixon, G.L., and 

Quinlivan, W.O., 1976, East-trending structural 

lineaments in central Nevada: U.S. Geological Survey 

Professional Paper 986, 16 p. 

Ekren, E.B., Byers, F.M., Jr., Hardyman, R.F., Marvin, R.F., 

and Silberman, M.L., 1980, Stratigraphy, preliminary 

petrology, and some structural features of Tertiary 

volcanic rocks in the Gabbs Valley and Gillis Ranges, 

Mineral County, Nevada: U.S. Geological Survey 

Bulletin 1464, 54 p. 

Ekren, E.B., Orkild, P.P., Sargent, K.A., and Dixon, G.L., 1978, 

Geologic map of Tertiary rocks, Lincoln County, Nevada: 

U.S. Geological Survey Miscellaneous Investigations 

Series Map I-1041, scale 1:250,000. 

Ekren, E.B., and Sargent, K.A., 1965, Geologic map of the 

Skull Mountain Quadrangle, Nye County, Nevada: U.S. 

Geological Survey Geologic Quadrangle Map GQ-387, 

scale 1:24,000. 

78 Index of Granitic Rock Masses in Nevada 

Erickson, R.L., Silberman, M.L., and Marsh, S.P., 1978, Age 

and composition of igneous rocks, Edna Mountain 

quadrangle, Humboldt County, Nevada: U.S. Geological 

Survey Journal of Research, v. 6, p. 727-743. 

Evans, J.G., and Ketner, K.B., 1971, Geologic map of the 

Swales Mountain quadrangle and part of the Adobe 

Summit quadrangle, Elko County, Nevada: U.S. 

Geological Survey Miscellaneous Geologic 

Investigations Map I-667, scale 1:24,000. 

Evernden, J.F., and Kistler, R.W., 1970, Chronology of 

emplacement of Mesozoic batholithic complexes in California and western Nevada: U.S. Geological Survey 

Professional Paper 623, 42 p. 

Fabiano, E.B., and Peddie, N.W., 1969, Grid values of total 

magnetic intensity IGRF-1965: U.S. Department of 

Commerce, Rockville, Md., E.S.S.A. Technical Report, 

C & GS-38. 

Ferguson, H.G., 1924, Geology and ore deposits of the Manhattan district, Nevada: U.S. Geological Survey Bulletin 

723, 163 p. 

Ferguson, H.G., and Cathcart, S.H., 1954, Geologic map of the 

Round Mountain quadrangle, Nevada: U.S. Geological 

Survey Geologic Quadrangle Map GQ-40, scale 

1:125,000. 

Ferguson, H.G., and Muller, S.W., 1949, Structural geology of 

the Hawthorne and Tonopah Quadrangles, Nevada: U.S. 

Geological Survey Professional Paper 216, 53 p. 

Ferguson, H.G., Muller, S.W., and Cathcart, S.H., 1954, 

Geology of the Mina Quadrangle, Nevada: U.S. 

Geological Survey Geologic Quadrangle Map GQ-45, 

scale 1:125,000. 

Fleck, RJ., 1970, Age and possible origin of the Las Vegas 

Valley shear zone, Oark and Nye Counties, Nevada: 

Geological Society of America Abstracts with Programs, 

v. 2, no. 5, p. 333. 

Garside, L.J., 1974, Geothermal exploration and development 

in Nevada through 1973: Nevada Bureau of Mines 

Report 21, 12 p. 

Gianella, V.P., 1957, Earthquake and faulting, Fort Sage 

Mountains, California, December 1950: Seismological 

Society of America Bulletin, v. 47, no. 3, p. 173-177. 

Gianella, V.P., and Callaghan, Eugene, 1934, The earthquake 

of December 20, 1932, at Cedar Mountain, Nevada, and 

its bearing on the genesis of Basin Range structure: 

Journal of Geology, v. 42, no. 1, p. 1-22. 

Gibbons, A.B., Hinrichs, E.N., Hansen, W.R., and Lemke, 

R.W., 1963, Geology of the Rainier Mesa Quadrangle, 

Nye County, Nevada: U.S. Geological Survey Geologic 

Quadrangle Map GQ-215, scale 1:24,000. 

Gilluly, James, and Masursky, Harold, 1965, Geology of the 

Cortez Quadrangle, Nevada, with a section on Gravity 

and aeromagnetic surveys, by D .R. Mabey: U.S. 

Geological Survey Bulletin 1175, 117 p. 

Gilluly, James, and Gates, Olcott, 1965, Tectonic and igneous 

geology of the northern Shoshone Range, Nevada, with a 

section on Gravity in Crescent Valley, by Donald Plouff: 

U.S. Geological Survey Professional Paper 465, 153 p. 

Granger, A.E., Bell, M.M., Simmons, G.C., and Lee, Florence, 

1957, Geology and mineral resources of Elko County, 

Nevada: Nevada Bureau of Mines Bulletin 54, 190 p. 
Gumper, F.J., and Scholz, Christopher, 1971, Microseismicity 

and tectonics of the Nevada seismic zone: Seismological 

Society of America Bulletin, v. 61, no. 5, p. 1413-1432. 

Hamilton, Warren, 1969, Mesozoic California and the underfloor of Pacific mantle: Geological Society of America 

Bulletin, v. 80, no. 12, p. 2409-2429. 

Harrold, J.L., 1972, K-Ar dates for plutonic rocks, Humboldt 

County, Nevada, and Harney County, Oregon: Isochron/ 

West, no. 5, p. 1-5. 

Hausen, D.M., and Kerr, P.F., 1968, Fine gold occurrence at 

Carlin, Nevada, in Ridge, J.D., ed., Ore deposits of the 

United States 1933-1967 (Graton-Sales Volume): New 

York, American Institute of Mining, Metallurgical, and 

Petroleum Engineers, p. 908-940. 

Hewett, D.F., 1956, Geology and mineral resources of the 

lvanpah Quadrangle, California and Nevada: U.S. 

Geological Survey Professional Paper 275, 172 p. 

Hope, R.A., 1976, Preliminary geologic map of Elko County, 

Nevada: U.S. Geological Smvey Open-File Report 

76-779, scale 1:100,000. 

Hose, R.K., Blake, M.C., Jr., and Smith, R.M., 1976, Geology 

and mineral resources of White Pine County, Nevada: 

Nevada Bureau of Mines and Geology Bulletin 85, 105 p. 

Johnson, M.G., 1977, Geology and mineral deposits of Pershing 

County, Nevada: Nevada Bureau of Mines and Geology 

Bulletin 89, 115 p. 

Johnston, W.P., 1972, K-Ar ages of Blind Mountain stock and 

Yuba Dike, Lincoln County, Nevada: Isochron/West, no. 

3, p. 30. 

Kane, M.F., Webring, M.W., and Bhattacharyya, B.K., 1981, A 

preliminary analysis of gravity and aeromagnetic surveys 

of the Timber Mountain area, southern Nevada: U.S. 

Geological Survey Open-File Report 81-189, 40 p. 

Kleinhampl, F.J., and Ziony, J.I., 1967, Preliminary geologic 

map of northern Nye County, Nevada: U.S. Geological 

Survey Open-File Map 67-613, scale 1:200,000. 

Knopf, Adolph, 1922, Ore deposits of Cedar Mountain, 

Mineral County, Nevada: U.S. Geological Survey 

Bulletin 725-H, p. 361-382. 

___ 1923, The Candelaria Silver district, Nevada: U.S. 

Geological Survey Bulletin 735-H, p. 1-22. 

Krueger, H.W., and Schilling, J.H., 1971, Geochron/Nevada 

Bureau of Mines K/ Ar age determinations; List 1: Isochron/West, no. 1, p. 9-14. 

Lee, D.E., Marvin, R.F., Stern, T. W., and Peterman, Z.E., 

1970, Modification of potassium-argon ages by Tertiary 

thrusting in the Snake Range, White Pine County, 

Nevada, in Geological Survey research 1970: U.S. 

Geological Survey Professional Paper 700-D, p. 

D92-D102. 

Locke, Augustus, Billingsley, P.R., and Mayo, E.B., 1940, Sierra 

Nevada tectonic patterns: Geological Society of America 

Bulletin, v. 51, no. 4, p. 513-540. 

LongwelJ, C.R., 1963, Reconnaissance geology between Lake 

Mead and Davis Dam, Arizona-Nevada, in Shorter 

contributions to general geology: U.S. Geological Survey 

Professional Paper 374-E, p. E1-E51. 

Longwell, C.R., Pampeyan, E.H., Bowyer, Ben, and Roberts, 

R.J., 1965, Geology and mineral deposits of Clark 

County, Nevada: Nevada Bureau of Mines Bulletin 62, 

218 p. 

Lovejoy, D.W., 1959, Overthrust Ordovician and the Nannie's 

Peak intrusive, Lone Mountain, Elko County, Nevada: 

Geological Society of America Bulletin, v. 70, no. 5, p. 

539-564. 

Lumsden, W.W., Jr., 1964, Geology of the southern White Pine 

Range and northern Horse Range, Nye and White Pine 

Counties, Nevada: Los Angeles, Calif., California 

University Ph. D. thesis, 249 p. 

Lutsey, LA., and Nichols, S.L., 1972, Land status map of 

Nevada: Nevada Bureau of Mines and Geology Map 40, 

scale 1:500,000. 

Maldonado, Florian, 1977, Summary of geology and physical 

properties of the Climax stock, Nevada Test Site: U.S. 

Geological Survey Open-File Report 77-356, 25 p. 

___ 1981, Geology of the Twinridge pluton area, Nevada 

Test Site, Nevada: U.S. Geological Survey Open-File 

Report 81-156, 13 p., scale 1:48,000. 

Marvin, R.F., and Cole, J.C., 1978, Radiometric ages-compilation A, U.S. Geological Survey: Isochron/West, no. 22, 

p. 3-14. 

Marvin, R.F., and Dobson, S.W., 1979, Radiometric 

ages-compilation B, U.S. Geological Survey: Isochron/ 

West, no. 26, p. 3-32. 

McDowell, F.W., 1971, K-Ar ages of igneous rocks from the 

western United States: Isochron/Wcst, no. 2, p. 1-16. 

McDowell, F.W., and Kulp, J.L., 1967, Age of intrusion and ore 

deposition in the Robinson mining district of Nevada: 

Economic Geology, v. 62, no. 7, p. 905-909. 

McKee, E.H., 1972, Preliminary geologic map of the Wildcat 

Peak quadrangle and the western part of the Diana's 

Punch Bowl quadrangle, Nevada: U.S. Geological Survey 

Miscellaneous Field Studies Map MF-337, scale 

1:62,500. 

McKee, E.H. Tarshis, A.L., and Marvin, R.F., 1976, Summary 

of radiometric ages of Tertiary volcanic and selected 

plutonic rocks in Nevada, Part V-northeastern Nevada: 

Isochron/West, no. 16, p. 15-27. 

Means, W.D., 1962, Structure and stratigraphy in the central 

Toiyabe Range, Nevada: University of California 

Publications in Geological Sciences, v. 42, no. 2, p. 

71-110. 

Merriam, C.W., and Anderson, C.A., 1942, Reconnaissance 

survey of the Roberts Mountains, Nevada: Geological 

Society of America Bulletin, v. 53, no. 12, p. 1675-1727. 

Miller, W.M., and Silberman, M.L., 1977, Cretaceous K-Ar age 

of hydrothermal alteration at the North Fish Creek 

porphyry copper prospect, Fish Creek Mountains, 

Lander County, Nevada: Isochron/West, no. 18, p. 7. 

Misch, Peter, and Hazzard, J.C., 1962, Stratigraphy and 

metamorphism of Late Precambrian rocks in central 

northeastern Nevada and adjacent Utah: American 

Association of Petroleum Geologists Bulletin, v. 46, no. 

3, p. 289, 302-303. 

Selected References 79 
Moore, J.G., 1969, Geology and mineral deposits of Lyon, 

Douglas, and Ormsby Counties, Nevada, with a section 

on Industrial minerals by N.L. Archbold: Nevada Bureau 

of Mines Bulletin 75, 45 p. 

Moores, E.M., 1963, Geology of the Currant area, Nye County, 

Nevada: Princeton, N.J., Princeton University Ph. D. 

thesis, 208 p. 

Moores, E.M., Scott, R.B., and Lumsden, W.W., 1968, Tertiary 

tectonics of the White Pine-Grant Range region, eastcentral Nevada, and some regional implications: 

Geological Society of America Bulletin, v. 79, no. 12, p. 

1703-1726. 

Morton, J.L., Silberman, M.L., Bonham, H.F., Gardsite, L.J., 

and Noble, D.C., 1977, K-Ar ages of volcanic rocks, 

plutonic rocks, and ore deposits in Nevada and eastern 

California-Determinations run under the USGSNBMG cooperative program: Isochron/West, no. 20, p. 

19-29. 

Muffler, L.J.P., 1964, Geology of the Frenchie Creek 

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Selected References 81