Mineral Resources of the Pahute Peak 

Wilderness Study Area, 

Humboldt County, Nevada

U.S. GEOLOGICAL SURVEY BULLETIN 1726-C

*4F?^

"- * * jL- <""<£*.. *:&&

Chapter C

Mineral Resources of the Pahute Peak 

Wilderness Study Area, 

Humboldt County, Nevada

By DONALD C. NOBLE, DONALD PLOUFF, 

JOEL R. BERGQUIST, and HARLAN N. BARTON 

U.S. Geological Survey

JERRY E. OLSON 

U.S. Bureau of Mines

U.S. GEOLOGICAL SURVEY BULLETIN 1726

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

HUMBOLDT AND PERSHING COUNTIES, NEVADA
DEPARTMENT OF THE INTERIOR 

DONALD PAUL MODEL, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1987

For sale by the

Books and Open-File Reports Section

U.S. Geological Survey

Federal Center, Box 25425

Denver, CO 80225

Library of Congress Cataloging-in-Publication Data

Mineral resources of the Pahute Peak Wilderness Study 

Area, Humboldt County, Nevada.

U.S. Geological Survey Bulletin 1726-C

Bibliography

Supt. of Docs. No.: I 19.3:1726-C

1. Mines and mineral resources Nevada Pahute Peak

Wilderness. 2. Geology Nevada Pahute Peak

Wilderness. 3. Pahute Peak Wilderness (Nev.) I. Noble,

Donald C. II. Geological Survey (U.S.) III. Series: U.S.

Geological Survey Bulletin 1726-C

QE75.B9 No. 1726-C 557.3s 87-600061

[TN24.N3] [553'.09793'54l
STUDIES RELATED TO WILDERNESS

Bureau of Land Management Wilderness Study Area

The Federal Land Policy and Management Act (Public Law 94-579, October 

21, 1976) requires the U.S. Geological Survey and the U.S. Bureau of Mines to 

conduct mineral surveys on certain areas to determine the values, if any, that may 

be present. Results must be made available to the public and be submitted to the 

President and the Congress. This report presents the results of a mineral survey 

of part of the Pahute Peak Wilderness Study Area (NV-020-621), Humboldt 

County, Nevada.

CONTENTS

Summary Cl

Abstract 1

Character and setting 1

Identified resources 1

Mineral resource potential 1 

Introduction 3

Area description 3

Previous and present investigations 3 

Appraisal of identified resources 3

Mining history 3

Mining claims 3

Mineralized areas 3

Copper Canyon anomalous area 3 

Pahute Peak anomalous area 5 

Clapper Creek anomalous area 5 

Other areas 5

Petrified wood 6

Geothermal energy 6 

Assessment of mineral resource potential 6

Geology 6

Geochemical studies 7

Geophysical studies 7 

Conclusions 8 

References cited 9 

Appendix. Definition of levels of mineral resource potential and certainty of

assessment and geologic time chart 11

FIGURES

1. Index map showing location of the Pahute Peak Wilderness Study Area, 

Humboldt County, Nevada C2

2. Map showing mineral resource potential and generalized geology of the 

Pahute Peak Wilderness Study Area, Humboldt County, Nevada 4

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

HUMBOLDT AND PERSHING COUNTIES, NEVADA

Mineral Resources of the Pahute Peak 

Wilderness Study Area, Humboldt County, Nevada

By Donald C. Noble, Donald Plouff, Joel R. Bergquist, 

and Harlan N. Barton 

U.S. Geological Survey

Jerry E. Olson

U.S. Bureau of Mines

SUMMARY

Abstract

The part of the Pahute Peak Wilderness Study 

Area (NV-020-621) requested for mineral surveys 

encompasses 25,200 acres in the central and southern 

parts of the Black Rock Range. Fieldwork for this 

report was done in 1984 and 1985. Three areas are 

identified as having mineral resource potential, and 

one area has potential for geothermal resources. An 

area at the northwest corner of the study area has 

moderate resource potential for gold, silver, copper, 

lead, zinc, molybdenum, and tungsten. An area 

adjacent and partially overlapping to the south has 

high resource potential for gold and silver. Most of 

the northern two-thirds of the study area has moderate 

resource potential for gold and silver. An area in the 

southwestern part of the study area has high potential 

for geothermal resources. There is low potential 

throughout the study area for mercury and uranium 

resources. Minor amounts of opal and petrified wood 

are found in the study area, but there are no 

indications of resource potential. In this report, 

references to the Pahute Peak Wilderness Study Area 

or study area refer only to that part of the wilderness 

study area requested by the U.S. Bureau of Leind 

Management for mineral surveys.

Character and setting

The Pahute Peak Wilderness Study Area is in the 

central and southern parts of the Black Rock Range in

Humboldt County, northwest Nev. (fig. 1). The study 

area includes some of the most rugged parts of the 

range, and relief locally exceeds 4,000 ft. A major 

active normal fault system bounds the west margin of 

the range. The area is underlain largely by slightly 

tilted rhyolitic to basaltic volcanic rocks of Oligocene 

and Miocene(?) age (fig. 2; see appendix for geologic 

time chart). Some of these rocks are hydrothermally 

altered, whereas others were altered by reaction with 

groundwater. Granodiorite to quartz monzonite of 

Cretaceous age and metasedimentary rocks of 

probable Mesozoic and Paleozoic age are exposed 

locally in the northwestern part of the study area. A 

few landslide masses are present along the west side of 

the Black Rock Range.

Identified Resources

There are no identified resources within the 

Pahute Peak Wilderness Study Area.

Mineral Resource Potential

The northwestern part of the study area around 

Copper Canyon is underlain by granitic and 

metasedimentary rocks and has moderate resource 

potential for gold, silver, copper, lead, molybdenum, 

tungsten, and particularly for zinc in skarn deposits. 

An area underlain by volcanic rock 2 mi south of 

Copper Canyon has high potential for gold and silver 

resources in precious-metal deposits of epithermal 

vein or disseminated type. Areas underlain by 

Cenozoic volcanic rocks in the central and northern

Cl
119°00'

/ v

)-/Soldier 

| / Meado 

)/ Ranch

A J

o

AREA OF MAP

41°00'

PAHUTE PEAK 

WILDERNESS 

STUDY AREA 

(NV-020-621)

!

5

O

O

m

Double 

Hot Springs 

KGRA

CQ

5 MILES

Figure 1. Index map showing location of the Pahute Peak Wilderness Study Area, Humboldt County, Nevada. 

Locations of Known Geothermal Resource Areas (KRGA) from Muffler (1979).

C2
parts of the study area have moderate resource 

potential for gold and silver in epithermal vein or 

disseminated deposits. The southwestern part of the 

study area has high potential for geothermal energy 

resources. The entire study area has low resource 

potential for mercury and uranium.

INTRODUCTION 

Area Description

The part of the Pahute Peak Wilderness Study 

Area (NV-020-621) studied covers 25,200 acres in the 

western part of the central and southern Black Rock 

Range in western Humboldt County, Nev. (fig. 1). The 

terrain is rugged over much of the study area, with 

elevations ranging from 4,005 ft in the southwestern 

part of the area to 8,594 ft at the summit of Pahute 

Peak (also known as Big Mountain). Cliffs and steep 

canyons are common, especially on the west slope of 

the range. The climate is arid to semiarid and 

vegetation is sparse, with saltbush, greasewood, and 

sagebrush the dominant vegetation.

The best access to the study area is from 

Gerlach via the Soldier Meadow County Road (HU 

217). From this road an unimproved dirt road 

generally follows the west margin of the study area. 

An unmapped but well-used jeep trail traverses the 

northern part of the study area, and unimproved jeep 

trails that cross the desert piedmont provide access to 

the west margin of the study area.

Previous and Present Investigations

The Pahute Peak Wilderness Study Area includes 

parts of the Big Mountain, Clapper Creek, Pidgeon 

Spring, and Pidgeon Spring SW 7 V2-minute 

quadrangles. Willden (1964) presented a geologic map 

of Humboldt County that differentiated Cenozoic and 

pre-Cenozoic rocks, but provides little detail of the 

Cenozoic stratigraphy. Unpublished reconnaissance 

geologic mapping of the Cenozoic rocks of the western 

part of Humboldt County by B.C. Noble, done for the 

geologic map of Nevada (Stewart and Carlson, 1978), 

served as the foundation for the geologic mapping done 

for this study. For information on mines and 

prospects, the U.S. Bureau of Mines searched 

Humboldt County claim records, U.S. Bureau of Land 

Management claim records, and U.S. Bureau of Mines 

production records. Claim owners were contacted for 

additional information and for permission to examine 

and publish data about their properties. Field studies 

to examine mines, prospects, and mineralized sites 

were carried out in 1984 by R.S. Gaps, J.E. Olson, and 

N.T. Zilka of the U.S. Bureau of Mines (Olson, 1986). 

All mineral properties identified were examined, 

sampled, and, if warranted, mapped.

The geochemical evaluation was based on data 

obtained from the geochemical evaluation of the study 

area by Barringer Resources, Inc. (1982), data on 

heavy-mineral concentrates (Day and Barton, 1986), 

and quantitative rock geochemical data (Olson, 1986). 

Rock geochemical data are available from the U.S.

Bureau of Mines, Western Field Operations Center, E. 

360 Third Avenue, Spokane, Washington, 99202.

APPRAISAL OF IDENTIFIED RESOURCES

By Jerry E. Olson, U.S. Bureau of Mines 

Mining History

Mining has occurred in districts near the Pahute 

Peak Wilderness Study Area, but only four prospects 

are located within the study area.

Alien Hardin reportedly found a 25-lb chunk of 

cerargyrite (horn silver) in 1849 near the study area 

(Vanderburg, 1938). Hardin City and a millsite were 

built (about 1 mi southwest of the present study area) 

subsequent to reports of the discovery of a "lost" silver 

mine. No workings exist near the millsite and there 

was apparently no production, but parts of the mill are 

still standing.

Mining Claims

U.S. Bureau of Land Management records 

indicate four areas under active or recent claim within 

or adjacent to the study area, and an additional claim 

was identified during field work. None of these claims 

are patented. The Copper Canyon area (fig. 2), at the 

north edge of the study area, is developed by numerous 

underground and surface workings. The remaining four 

claim blocks are 2 to 4 mi south of Copper Canyon. 

Workings are limited to a few small pits. Workings 

reported by the U.S. Bureau of Land Management 

(1983) near Clapper Creek were not found.

Mineralized Areas

Three mineralized areas were sampled by the 

U.S. Bureau of Mines. These three areas correspond to 

three areas discussed by the U.S. Bureau of Land 

Management (1983) and are based largely on 

interpretation of geochemical data in Barringer 

Resources, Inc. (1982).

Copper Canyon Area

Within the Copper Canyon area there are 

numerous workings, including a 300-ft adit near the 

mouth of the canyon. Several smaller adits and pits 

expose narrow quartz veins and probable poorly 

developed skarn zones. In the 28 rock samples 

analyzed by the U.S. Bureau of Mines, gold values were 

at or below detection limits. Molybdenum, tin, and 

tungsten were not detected. Silver values were 

generally low, but two samples contain 15 and 17 parts 

per million (ppm). Zinc concentrations in four samples 

from shear and gossan zones range from 0.018 to 8.7 

weight percent and was detected in amounts ranging 

from 0.8 to 8 weight percent in three other rock 

samples. Because zinc-bearing skarns are commonly 

found distant from the source (Einaudi and others,

C3
n9°07'30"

41°17'30"

41°07'30" -

118°57'30'

I

M/C Au, Ag,Cu, Pb, Zn, Mo, W [ 4 ] [ 5 ] [ 6 ]

M/B Au, Ag [ 7 ]

IWzPzg

H/C Au, Ag [ 2 ] [ 3 ]

L/B Hg, U [ 8 ] [ 9 ] 

(Entire study area)

APPROXIMATE BOUNDARY OF

PAHUTE PEAK WILDERNESS STUDY AREA 

(NV-020-621)

H/C Geothermal [ 1 ]

5 MILES ° Hardin City

Figure 2. Mineral resource potential and generalized geology of the Pahute Peak Wilderness Study Area, 

Humboldt County, Nevada.

C4
1981), the data may imply a source pluton beneath the 

Cenozoic volcanic rocks.

About 2 mi south of Copper Canyon a 20- to 30- 

ft-wide fault zone can be traced for at least 0.25 mi 

along the range front. This zone strikes N. 30° W. and 

dips 80° S. Within this zone, silicified volcanic and 

intrusive rocks contain disseminated pyrite and are cut 

by iron oxide-filled veinlets. Less than 0.25 mi farther 

south, another area of more pervasive argillic and

EXPLANATION

Area with high mineral resource potential 

Area with moderate mineral resource potential 

Area with low mineral resource potential

See appendix for definition of levels of mineral resource potential and certainty 

of assessment

Commodities

Ag

Au

Cu

Hg

Mo

Pb

U

W

Zn

Silver

Gold

Copper

Mercury

Molybdenum

Lead

Uranium

Tungsten

Zinc

[ ] Deposit types

1 Geothermal water

2 Epithermal base- and precious-metal vein deposits

3 Hot-spring low-grade gold

4 Porphyry base metals

5 Zinc-bearing skarn

6 Replacement

7 Volcanic-hosted gold

8 Epithermal mercury

9 Volcanogenic uranium

Geologic map units

Qac Alluvium and colluvium (Quaternary) Locally includes lake

sediments and sand dunes 

Ql Landslide deposits (Quatcrnary)-Locally includes colluvium,

alluvium, and talus 

Tl Rhyolite, dacite, and basalt (Miocene? and Oligoccnc) 

Includes interbcddcd tuffs and volcaniclastic sedimentary rock 

Ta Rhyolite ash-flow and air-fall tuffs (Oligoccne) Ashdown Tuff

and local units of volcaniclastic sedimentary rock 

Tr Rhyolite (Oligoccne)-Domcs, short flows, and dikes 

Tb Basalt (Oligocene)-Flows, dikes, and sills with interbcds of tuff

and volcaniclaslic sedimentary rocks 

M/.Pzg Granitic and mctasedimentary rocks (Mcso/.oic and Palcozoic?)-

Includes quartz monzonite and granodiorite of Cretaceous age

and locally metamorphosed limestone and other sedimentary

rocks that may range from Mississippian to Cretaceous age

 Contact-Dashed where approximately located 

_1 _ _.. Fault Dashed where approximately located; dotted where concealed. Bar and ball on downthrown side 

X Prospect

Figure 2. Continued.

silicic alteration is present along the same trend. 

Three pits in this area expose strongly altered volcanic 

and plutonic (gabbroic?) rocks with visible primary 

sulfide minerals (probably chalcopyrite and 

arsenopyrite) and minor secondary copper minerals 

(Olson, 1986). Of 14 samples taken from the rangefront fault zone and from old workings, 8 contain 

detectable amounts of gold, and 12 samples have 

detectable silver. The maximum and median values 

for gold and silver were 2.8 and 1.2, and 1.6 and 0.7 

ppm respectively (Olson, 1986). Anomalous arsenic 

values in six samples range from 0.1 to 17 weight 

percent. Antimony is present in six samples and 

ranges from 3.0 to 33 ppm. The alteration and 

anomalous precious-metal concentrations, which may 

be related to hydrothermal (hot spring) activity along 

the range-front zone, may indicate a larger 

mineralized area. No other workings or evidence of 

alteration or mineralization were found within the 

Copper Canyon area.

Pahute Peak Area

The Pahute Peak area is south of the Copper 

Canyon zone in the northwestern part of the study 

area. Two pits expose a fluorite vein that cuts 

volcanic and altered intrusive rocks on the north side 

of an unnamed canyon about 2.5 mi southeast of 

Copper Canyon. The vein is 2 to 4 ft wide, strikes 

east, and can be traced for about 300 ft. The vein 

contains massive fluorite with cryptocrystalline silica 

and opaque minerals. Two samples of vein material 

contain 20 percent and 10 percent fluorine (41 percent 

and 21 percent, respectively, of equivalent CaF2). 

Resources were not quantified because of the low 

grade and lack of exposure. One sample of charcoal(?) 

in tuff from the upper end of the same canyon contains 

0.06 percent equivalent uranium (Garside, 1973). The 

presence of vein fluorite, uranium oxide, and trace 

amounts of molybdenum, tungsten, and gold in rock 

chip samples, and the close proximity of a rhyolite 

dome, may be indicative of a buried porphyry 

molybdenum system (Burt and others, 1982). No other 

workings were found in the area. Of 25 samples taken 

at selected sites, four contain from 0.04 to 0.22 ppm 

gold and two contain about 2 ppm silver (Olson, 

1986).

Clapper Creek Area

Five samples collected along a ridge 1 mi 

northwest of Clapper Creek from silicified rhyolite 

domes contain 0.4 to 0.9 ppm silver. A 5-ft adit and 

numerous small pits reported at an andesite-quartzite 

contact by the U.S. Bureau of Land Management were 

not found by the U.S. Bureau of Mines (Olson, 1986).

Other Areas

No workings were found elsewhere in the Pahute 

Peak Wilderness Study Area. Of 105 samples taken by 

the U.S. Bureau of Mines outside the areas discussed 

above, 10 contain detectable amounts of gold and 

silver (Olson, 1986). These were collected in the

C5
southernmost part of the study area, northeast, east, 

and southeast of Clapper Creek, and southeast of 

Pahute Peak.

Five samples were collected within the study 

area for analysis of zeolite minerals. The two samples 

with the most zeolites contained only 9 percent 

clinoptilolite and are therefore not considered 

important source rocks for zeolite minerals.

Petrified Wood

Petrified (opalized) wood is found in 

volcaniclastic beds interbedded with basalt at four 

sites about 1 mi south of Clapper Creek. Petrified 

wood fragments range in size from small chips to one 

partially buried log about 50 ft long and 3 ft in 

diameter. Because the areas are largely inaccessible 

by vehicle, the large segments would be difficult to 

excavate. Smaller pieces may be of limited 

commercial or recreational interest.

Geothermal Energy

Double Hot Springs is about 4 mi southwest of 

the south end of the study area (fig. 1). There are 

several springs with surface temperatures of about 

176 F and a mean reservoir temperature of about 

261 °F (Brook and others, 1979). The Black Rock Point 

hydrothermal area is about 7 mi south of the south end 

of the study area and has springs with temperatures to 

194 °F and a mean reservoir temperture of about 

264 °F (Brook and others, 1979). Both of these hot 

spring areas are within the Double Hot Springs Known 

Geothermal Resource Area (KGRA), which is adjacent 

to the south end of the study area (fig. 1).

The Soldier Meadow hydrothermal area (KGRA) 

is about 6 mi northwest of the northwest corner of the 

study area (fig. 1) and includes several springs with 

surface temperatures of about 129 °F and a subsurface 

temperature of about 239 °F (White and Williams, 

1975).

ASSESSMENT OF MINERAL RESOURCE POTENTIAL

By Donald C. Noble, Donald Plouff, Joel R. Bergquist, 

and Harlan N. Barton 

U.S. Geological Survey

Geology

The Black Rock Range is a fault-block range that 

is structurally typical of the Basin and Range 

province. Major normal fault systems of late Cenozoic 

age bound both the east and west margins of the 

range. The western fault system is presently active, 

and the total throw is greater in most places than that 

of the eastern fault system. Like the Calico 

Mountains to the west and the Jackson Mountains to 

the east, parts of the range are slightly tilted to the 

east. Both the Black Rock Range and the Pahute Peak

Wilderness Study Area are underlain almost entirely by 

volcanic rocks of Oligocene and Miocene(?) age.

Granodiorite and quartz monzonite, which are 

similar to other plutonic rocks in western Nevada, are 

exposed over about 0.75 mi between Copper Canyon 

and Clapper Creek. Radiometric age determinations 

of 96 million years (Ma) indicate that these rocks are 

of Cretaceous age (Smith and others, 1971). Small 

bodies of metamorphosed limestone and other 

sedimentary rocks, intruded by the plutonic rocks, 

probably correlate with strata of Mississippian to 

Cretaceous age exposed in the southernmost part of 

the Black Rock Range, 20 mi northeast in the Pine 

Forest Range, and 30 mi east in the Jackson Mountains 

(Silberling and Jones, 1984).

The Cenozoic stratigraphy of western Humboldt 

County has been discussed by Noble and others (1970, 

1973). On the basis of this work and on mapping 

carried out as part of the present study, the Cenozoic 

rocks in the Pahute Peak study area can be subdivided 

into four units.

The lowermost volcanic unit consists of flows, 

dikes, and sills of basalt that interfinger with and 

intrude bedded tuffs, volcanic sandstones, and related 

strata. The basalts contain phenocrysts of plagioclase, 

clinopyroxene, and olivine, the latter typically altered, 

in a generally glassy or originally glassy groundmass. 

The volcaniclastic rocks locally contain logs, stumps, 

and smaller fragments of petrified wood. Both the 

flow rocks and pyroclastic rocks have been subjected 

to pervasive low-grade alteration characterized by the 

formation of abundant smectite and other secondary 

minerals. The highly irregular nature of the dikes and 

sills and the intricate manner in which the mafic flows 

intrude and interfinger with the pyroclastic rocks 

suggests that the flows were erupted through wet, 

unconsolidated pyroclastic strata.

The basalts of the lowermost volcanic unit are 

late Oligocene or older and underlie rocks of late 

Oligocene age. The basalts were dated at 26.3±0.9 Ma 

using potassium-argon methods on a whole-rock sample 

of basalt from the northern part of the study area 

(Noble and others, 1973). Ages were recalculated 

using presently accepted constants. Because the dated 

sample contained a small amount of glassy 

groundmass, the radiometric age should be considered 

a minimum.

The next unit is made up of rhyolite domes, short 

flows, and dikes. The domes overlie and intrude the 

basalts and associated sedimentary rocks. The domes, 

which contain phenocrysts of plagioclase, sanidine, 

quartz, and biotite, typically show well-developed flow 

banding and commonly have marginal glassy zones. An 

Oligocene age is required for the rhyolites because of 

the radiometric ages available for the underlying and 

overlying units.

The third of the four Cenozoic units is composed 

of volcaniclastic rocks of rhyolitic composition that 

are exposed largely on the west flank of the Black 

Rock Range. Included in this unit is a distinctive 

reddish, reddish-brown- to orange-weathering ash-flow 

tuff, called the Ashdown Tuff (Noble and others, 1970), 

that is densely welded in most localities. The Ashdown 

Tuff is also exposed in the northern Black Rock Range 

and in the Pine Forest Range (Noble and others, 

1970). Other units of ash-flow tuff are exposed

C6
locally, and north of Clapper Creek five ash-flow 

sheets can be recognized. These tuffs are medial to 

distal parts of ash-flow sheets from source areas 

outside of the Pahute Peak Wilderness Study Area.

Potassium-argon ages of about 25 Ma were 

obtained on the Ashdown Tuff in the northern part of 

the Black Rock Range, using presently accepted 

constants (Noble and others, 1970). Although no ages 

are available for the ash-flow sheets that underlie the 

Ashdown Tuff, regional relations (Noble, 1972; 

Robinson and others, 1984; Duffield and McKee, 1986) 

suggest that all the rocks of this unit are of late 

Oligocene age.

The fourth and stratigraphically highest unit is 

composed of ash-flow and air-fall tuffs that are 

overlain and intruded by buff- to black-weathering 

flows of rhyolite, dacite, and basalt. These rocks 

range from platy-weathering rhyolite flows exposed on 

Pahute Peak to olivine-bearing basalt exposed in the 

southern part of the study area. Pyroxene-bearing 

felsic rocks of probable ferrodacite composition are 

also common. A potassium-argon age of 25.9+0.9 Ma 

was obtained on a sample from this unit taken south of 

Clapper Creek. Similar ages have been obtained on 

correlative flows in the northern and central parts of 

the Black Rock Range (Noble and others, 1973). The 

lava flows of this group overlie the Ashdown Tuff and 

are in turn overlain elsewhere by the Summit Lake 

Tuff of Miocene (about 16 Ma) age (Noble and others, 

1970).

Mafic flows that contain phenocrysts of olivine, 

clinopyroxene, and plagioclase overlie the rhyolitic and 

ferrodacitic flows in the southern part of the study 

area. These rocks probably are either of similar age to 

the underlying late Oligocene rhyolitic and rhyodacitic 

flows, or are correlative with basalts of middle 

Miocene age in other parts of northwestern Nevada 

and southeastern Oregon (Noble and others, 1970; 

Stewart and Carlson, 1978; Hart and Carlson, 1985).

Many landslides are present on the west side of 

the Black Rock Range (Stewart and Carlson, 1978), and 

parts of the study area are underlain by landslide 

material. In places it is difficult to distinguish normal 

faults from slip surfaces, and areas near Clapper 

Creek that are mapped as bedrock may in fact be 

underlain by landslide material. In addition to 

alluvium, colluvium, talus, and landslide deposits, the 

Quaternary deposits in the southwestern part of the 

study area include lake sediments and sand dunes.

The granitic and metasedimentary rocks of preCenozoic age and, locally, the volcanic and 

sedimentary rocks of Cenozoic age are hydrothermally 

altered. Much alteration of originally glassy Tertiary 

volcanic rocks, particularly of the lowest volcanic 

unit, probably represents a combination of weathering 

and post-depositional alteration of highly reactive 

volcanic glass by groundwater.

Geochemical Studies

A wide range of major- and minor-element data 

on stream-sediment samples collected and analyzed by 

Barringer Resources, Inc. (1982), formed the principal

data base for geochemical studies of the Pahute Peak 

Wilderness Study Area. Forty-seven samples were 

collected within the study area, giving a sampling 

density of about 1 sample per mi . In addition, the 

U.S. Geological Survey took 23 samples of heavymineral concentrates from stream sediment along the 

west edge of the Pahute Peak Wilderness Study Area.

Samples were analyzed for 31 elements (Ag, As, 

Au, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, La, Mg, Mn, 

Mo, Nb, Ni, Pb, Sb, Sc, Sn, Sr, Th, Ti, V, W, Y, Zn, and 

Zr) using a six-step semiquantitative emission 

spectrographic method (Grimes and Marranzino, 

1968). Results of the analyses from the study area are 

given by Day and Barton (1986).

Barringer Resources, Inc. (1982), reports 

anomalous concentrations of barium, zinc, and 

molybdenum in the northwestern part of the Pahute 

Peak Wilderness Study Area. They relate these 

anomalous concentrations to their "mafic coppernickel, base and precious metals, and epithermal goldsilver models". Sporadic arsenic values of 10 to 78 

ppm and a single zinc value of about 200 ppm probably 

contributed significantly to anomalous composite 

values for the Barringer "base and precious metals and 

epithermal gold-silver models." These results are 

corroborated by U.S. Geological Survey data that 

include one sample of heavy-mineral concentrate from 

the Copper Canyon area that contains the following 

values in ppm: arsenic, 2,000; antimony, 500; lead, 

15,000; and zinc, greater than 20,000. The anomaly is 

also corroborated by the rock-chip sampling done by 

the U.S. Bureau of Mines (Olson, 1986).

Data from the U.S. Bureau of Mines (Olson, 1986) 

define a zone with highly anomalous concentrations of 

gold, silver, arsenic, and antimony located about 2 mi 

south of Copper Canyon. In addition, anomalous 

concentrations of gold and silver were found north of 

Clapper Creek and at localities several miles 

northeast, east, and south of Clapper Creek. Slightly 

anomalous concentrations of cobalt, chromium, 

copper, and nickel values reported by Barringer 

Resources, Inc. (1982), probably are related to basalts 

that overlie the granitic and sedimentary rocks.

Garside (1973) reported uranium-impregnated 

fossil wood within the study area. However, there is 

no evidence of anomalous concentrations of uranium in 

stream-sediment samples from the study area.

Although there are a number of mercury 

occurrences in northwestern Nevada (Williams and 

Compton, 1953; Bonham, 1969), there is no evidence of 

anomalous concentrations of mercury within the study 

area.

Geophysical Studies

J.S. Duval (written commun., 1985) estimated 

concentrations of potassium, equivalent uranium, and 

equivalent thorium by examining composite-color maps 

of gamma-ray spectrometric data. The maps were 

prepared at a scale of 1:1,000,000 from radiometric 

data acquired in regional surveys contracted by the 

U.S. Department of Fjiergy as part of the National 

Uranium Resources Evaluation (NURE) Program.

C7
East-trending flightlines were flown at altitudes of 

about 400 ft above mean terrain with a 3-mi spacing 

(Geodata International, Inc., 1979). Anomalous 

radioelement concentrations based on criteria 

discussed by Duval (1983) indicate that the study area 

has moderate radioactivity with values of 2 to 3 

weight percent potassium, 2.0 to 3.5 ppm equivalent 

uranium, and 7 to 12 ppm equivalent thorium.

An aeromagnetic survey of the region was flown 

at a constant barometric elevation of 9,000 ft above 

sea level with east-trending flightlines spaced at 2-mi 

intervals (U.S. Geological Survey, 1972). Contoured 

aeromagnetic data reveal a gradient of northwesttrending contours of magnetic intensity over most of 

the study area. This prominent magnetic gradient 

occurs between a 15- by 25-mi magnetic high centered 

1 mi north of the northeast corner of the study area 

and a 15- by 15-mi magnetic low centered about 1 mi 

west of the center of the west edge of the study 

area. The amplitudes of the anomalies are about 700 

nanoteslas (nT) and 150 nT, respectively. A minor 

closure of the complex magnetic high occurs at about 

the midpoint of the east edge of the study area. A 

minor closure of the low occurs at the midpoint of the 

west edge of the study area.

The broad magnetic high partly reflects the 

magnetization of Tertiary volcanic rocks exposed at 

the surface, because a nose of the magnetic high 

generally overlies the crestline of the Black Rock 

Range, and the periphery of the anomaly partly follows 

the border of the range. The contours that enclose the 

magnetic high generally are not correlated with 

topography, and the amplitude and areal extent of the 

magnetic high are unlike the irregular magnetic 

pattern typically associated with near-surface Tertiary 

volcanic rocks. Therefore, the large magnetic high 

may, in large part, reflect an underlying mafic pluton 

with relatively high magnetization. The thickness of 

this body is uncertain because the extent of the 

steepest gradients along the edges of the central high 

indicates that the maximum depth to the top of the 

mafic pluton could be as much as 1.5 mi beneath the 

surface.

Donald Plouff and C.F. Erdman established two 

gravity stations in the northern part of the study area 

and eight stations north of the study area to 

supplement gravity data from the National 

Geophysical Data Center (1984). The preliminary 

Bouguer gravity anomaly map (Donald Plouff, unpub. 

data, 1985) shows a northeast-elongated, 5- by 8-mi 

gravity high with an amplitude of 8 millgals (mGal), 

which nearly coincides with the central part of the 

magnetic high. Noses of the gravity high, which 

extend farther northwest and northeast, also correlate 

with the shape of the magnetic high. A small gravity 

high with an amplitude of about 4 mGal is correlated 

with a small magnetic high in the southernmost part of 

the study area. A small gravity low correlates with a 

saddle in the magnetic high near lat 41° 16' east of the 

study area. Closely spaced north-northwest-trending 

gravity contours along the west edge of the study area 

apparently reflect the steep contact between the 

dense body with high magnetization to the north and 

the less dense sediments and rocks beneath the 

western arm of the Black Rock Desert.

CONCLUSIONS

The evaluation of mineral resource potential is 

based on a variety of data that include the geologic, 

geochemical, and geophysical features, a survey of 

mines and prospects, and the mineral resources present 

in the surrounding regions. Mineral resource potential 

was classified using the system of Goudarzi (1984).

The potential for the following types of 

resources were evaluated for the Pahute Peak 

Wilderness Study Area: (1) base-metal (copper, zinc, 

lead, molybdenum, tungsten) and associated preciousmetal (gold-silver) deposits of porphyry, skarn, 

replacement, and vein type, (2) epithermal preciousmetal (gold-silver) deposits of vein, disseminated, and 

hot-spring type, (3) volcanic-hosted uranium deposits, 

(4) deposits of petrified wood and opal, and (5) 

geothermal energy resources.

The alteration of Mesozoic granitic and 

metamorphic rocks exposed in prospect workings near 

Copper Canyon and in other areas of the Black Rock 

and Pine Forest Ranges, combined with locally 

anomalous metal values, indicate a potential in the 

Copper Canyon area for porphyry, skarn, and 

replacement deposits of base and precious metals, and 

particularly skarn and replacement deposits of zinc. 

The area involved is restricted to outcrops of preCenozoic rock and areas directly east of outcrops 

where granitic rocks are overlain by a relatively thin 

cover of Cenozoic volcanic rocks. These areas have 

moderate resource potential, certainty level C, for 

gold, silver, copper lead, molybdenum, tungsten, and 

zinc. See appendix for definition of levels of 

resource potential and certainty of assessment.

Anomalous concentrations of gold, silver, 

arsenic, and antimony were found in an area with 

moderate to strong hydrothermal alteration along the 

western margin of the range about 2 mi south of 

Copper Canyon. The metal concentrations and 

alteration appear to be related to hydrothermal 

solutions localized by a normal fault zone of late 

Cenozoic age. This area has high resource potential, 

certainty level C, for gold and silver in epithermal 

vein or hot-spring type deposits.

Anomalous concentrations of gold and silver 

were recognized near Clapper Creek. Volcanic-hosted 

gold deposits of late Cenozoic age are known in 

northwestern Nevada, for example the Hog Ranch 

property, located in the northern part of the Leadville 

mining district, northern Washoe County, Nev. The 

central and northern parts of the study area thus have 

moderate resource potential, certainty level B, for 

gold and silver.

Although mercury deposits are known in 

northwestern Nevada, no anomalous concentrations of 

mercury were detected within the study area, and the 

study area has low potential, certainty level B, for 

mercury deposits.

Anomalous radioactivity was reported just below 

the west face of Pahute Peak, in the lowermost 

volcanic unit, and a sample of carbonized wood 

contained 0.06 percent equivalent uranium oxide 

(Garside, 1973). The petrified wood is sporadically 

distributed, and the stream-sediment survey conducted 

by Barringer Resources, Inc. (1982), did not reveal

C8
anomalous uranium values. No anomalous 

radioelement concentrations were recognized during 

an aerial gamma-ray survey. The study area has a low 

potential, certainty level B, for uranium resources.

Petrified wood is present in the Cenozoic 

sedimentary rocks of the lowermost volcanic unit. 

However, judging by its quality and lack of 

exploitation, it appears to be too sparse and too low 

grade to be considered a resource.

Although opal is mined locally in the Calico 

Mountains, rocks similar to the Calico host rocks are 

exposed over only a very small area in the 

southernmost part of the study area. There is no 

evidence of resource potential for opal.

From these investigations, it appears that the 

most important potential resource in the Pahute Peak 

Wilderness Study Area is geothermal energy. The 

northern part of the Double Hot Springs KGRA, which 

includes the Black Rock Point area, is adjacent to the 

southern tip of the study area (fig 1.). The Soldier 

Meadow KGRA is about 6 mi northwest of the study 

area. The mean reservoir temperatures of these areas 

were estimated to be about 261 to 264 °F and 239 °F, 

respectively (Brook and others, 1979; Renner and 

others, 1975; Mariner and others, 1974). No deep 

drilling for geothermal resources has been done in 

either KGRA. At present, only the hottest water in 

these KGRA's has marginal value for electrical 

generation, although it would be useful for industrial 

processing applications. The western part of the 

southern half of the study area has high potential for 

geothermal energy resources. This part of the Pahute 

Peak Wilderness Study Area has high potential, 

certainty level C, for geothermal resources.

REFERENCES CITED

Barringer Resources, Inc., 1982, Geochemical and 

geostatistical evaluation of wilderness study areas, 

Winnemucca District, northwest Nevada, prepared 

for United States Bureau of Land Management: 

Golden, Colo., 5 v., 24 pi., scale 1:250,000.

Bonham, H.F., 1969, Geology and mineral deposits of 

Washoe and Storey Counties, Nevada, with a 

section on Industrial minerals, by K.G. Papke: 

Nevada Bureau of Mines and Geology Bulletin 70, 

140 p.

Brook, C.A., Mariner, R.H., Mabey, D.R., Swanson, 

J.R., Guffanti, Marianne, and Muffler, L.J.P., 1979, 

Hydrothermal convection systems with reservoir 

temperatures 90° C., in Assessment of 

Geothermal Resources of the United States: U.S. 

Geological Survey Circular 790, p. 18-85

Burt, D.B., Sheridan, M.F., Bikun, J.V., and 

Christiansen, E.H., 1982, Topaz rhyolitesdistribution, origin, and significance for 

exploration: Economic Geology, v. 77, p. 1818- 

1836.

Day, G.W., and Barton, H.N., 1986, Analytical results 

and sample locality map of heavy-mineralconcentrate samples from the Pahute Peak 

Wilderness Study Area (NV-020-621), Humboldt 

County, Nevada: U.S. Geological Survey Open File 

Report 86-0271, 9 p.

Duffield, W.A., and McKee, E.H., 1986, 

Geochronology, structure, and basin and range 

tectonics of the Warner Range, northeastern 

California: Geological Society of America 

Bulletin, v. 97, p. 142-146.

Duval, J.S., 1983, Composite color images of aerial 

gamma-ray spectrometric data: Geophysics, v. 48, 

no. 6, p. 722-735.

Einaudi, M.T., Meinert, L.D., and Newberry, R.J., 

1981, Skarn deposits, in Skinner, B.J., ed., 

Economic Geology, Seventy-fifth Anniversary 

volume, p. 317-391.

Garside, L.J., 1973, Radioactive mineral occurrences 

in Nevada: Nevada Bureau of Mines and Geology 

Bulletin 81, 121 p.

Geodata International, Inc., 1979, Aerial radiometric 

and magnetic survey, Vya national topographic 

map, Nevada: U.S. Department of Energy OpenFile Report GJBX-136 (79), v. 2.

Goudarzi, G.H., 1984, Guide to preparation of mineral 

survey reports on public lands: U.S. Geological 

Survey Open-File Report 84-787, 42 p.

Grimes, D.J., and Marranzino, A.P., 1968, Directcurrent arc and alternating-current spark 

emmission spectrographic field methods for the 

semiquantitative analysis of geologic materials: 

U.S. Geological Survey Circular 591, 6 p.

Hart, W.K., and Carlson, R.W., 1985, Distribution and 

geochronology of Steens Mountain-type basalts 

from the northwestern Great Basin: Isochron/West, 

no. 43, p. 5-10.

Mariner, R.H., Rapp, J.B., Willey, L.M., and Presser, 

T.S., 1974, Chemical composition and estimated 

minimum thermal reservoir temperatures of 

principal hot springs of northern and central 

Nevada: U.S. Geological Survey Open-File Report, 

74-1066, 32 p.

Muffler, L.J.P., ed., 1979, Assessment of geothermal 

resources of the United States 1978: U.S. 

Geological Survey Circular 790, map 1, scale 

1:2,500,000.

National Geophysical Data Center, 1984, DMA gravity 

file of the U.S.: Boulder, Colo., National Oceanic 

and Atmospheric Administration, 2 magnetic tapes.

Noble, D.C., 1972, Some observations on the Cenozoic 

volcano-tectonic evolution of the Great Basin, 

western United States: Earth and Planetary 

Science Letters, v. 17, p. 142-150.

Noble, D.C., Hedge, C.E., McKee, E.H., and Korringa, 

M.K., 1973, Reconnaissance study of the strontium 

isotopic composition of Cenozoic volcanic rocks in 

the northwestern Great Basin: Geological Society 

of America Bulletin, v. 84, p. 1393-1406.

Noble, D.C., McKee, E.H., Smith, J.G., and Korringa, 

M.K., 1970, Stratigraphy and geochronology of 

Miocene rocks in northwestern Nevada: U.S. 

Geological Survey Professional Paper 700-D, p. 

D23-D32.

Olson, I.E., 1986, Mineral resources of the Pahute 

Peak Wilderness Study Area, Humboldt County, 

Nevada: U.S. Bureau of Mines Mineral Land 

Assessment Open-File Report, MLA-13-86, 20 p.

Renner, J.L., White, D.E., and Williams, D.L., 1975 

Hydrothermal convection system, in White, D.E., 

and Williams, D.L., eds., 1975, Assessment of

C9
geothermal resources of the United States 1975, 

U.S. Geological Survey Circular 726, 155 p.

Robinson, P.T., Brem, G.F., and McKee, E.H., 1984, 

John Day Formation of Oregon: A distal record of 

early Cascade volcanism: Geology, v. 12, p. 229- 

232.

Silberling, N.J., and Jones, D.L., eds., 1984, 

Lithotectonic terrane maps of the North American 

Cordillera: U.S. Geological Survey Open-File 

Report 84-0523, 106 p., scale 1:2,500,000.

Smith, J.G., McKee, E.H., Tatlock, D.B., and Marvin, 

R.F., 1971, Mesozoic granitic rocks in northwestern 

Nevada: A link between the Sierra Nevada and 

Idaho batholiths: Geological Society of America 

Bulletin, v. 82, p. 2933-2944.

Stewart, J.H., and Carlson, J.E., 1978, Geologic map 

of Nevada: U.S. Geological Survey, scale 

1:500,000.

U.S. Bureau of Land Management, 1983, Wilderness

technical report, Winnemucca district, Nev., 408 p.

U.S. Geological Survey, 1972, Aeromagnetic map of 

the Vya and part of the McDermitt 1° by 2° 

quadrangles, Nevada: U.S. Geological Survey 

Open-File Report, 1 pi., scale 1:250,000.

Vanderburg, W.O., 1938, Reconnaissance of mining 

districts in Humboldt County, Nevada: U.S. Bureau 

of Mines Information Circular 6995, 54 p.

White, D.E., and Williams, D.L., eds., 1975, 

Assessement of geothermal resources of the United 

States: U.S. Geological Survey Circular 726, 155 p.

Willden, Ronald, 1964, Geology and mineral deposits of 

Humboldt County, Nevada: Nevada Bureau of 

Mines Bulletin 59, 154 p.

Williams, Howel, and Compton, R.R., 1953, Quicksilver 

deposits of Steens Mountain and Pueblo Mountains, 

southeast Oregon: U.S. Geological Survey Bulletin 

995-B, p. 19-77.

CIO
APPENDIX. Definition of levels of mineral resource potential and 

certainty of assessment

Definitions of Mineral Resource Potential

LOW mineral resource potential is assigned to areas where geologic, geochemical, and geophysical characteristics define a geologic environment in which the existence of resources is unlikely. This broad 

category embraces areas with dispersed but insignificantly mineralized rock as well as areas with few 

or no indications of having been mineralized.

MODERATE mineral resource potential is assigned to areas where geologic, geochemical, and geophysical 

characteristics indicate a geologic environment favorable for resource occurrence, where interpretations 

of data indicate a reasonable likelihood of resource accumulation, and (or) where an application of 

mineral-deposit models indicates favorable ground for the specified type(s) of deposits.

HIGH mineral resource potential is assigned to areas where geologic, geochemical, and geophysical characteristics indicate a geologic environment favorable for resource occurrence, where interpretations of 

data indicate a high degree of likelihood for resource accumulation, where data support mineral-deposit 

models indicating presence of resources, and where evidence indicates that mineral concentration has 

taken place. Assignment of high resource potential to an area requires some positive knowledge that 

mineral-forming processes have been active in at least part of the area.

UNKNOWN mineral resource potential is assigned to areas where information is inadequate to assign low, 

moderate, or high levels of resource potential.

NO mineral resource potential is a category reserved for a specific type of resource in a well-defined 

area.

Levels of Certainty

U/A

UNKNOWN

POTENTIAL

H/B

HIGH POTENTIAL

M/B

MODERATE POTENTIAL

L/B

LOW

POTENTIAL

H/C

HIGH POTENTIAL

M/C 

MODERATE POTENTIAL

L/C

LOW

POTENTIAL

H/D

HIGH POTENTIAL

M/D

MODERATE POTENTIAL

L/D

LOW POTENTIAL

N/D

NO POTENTIAL

o

a.

I

LU 

OC

u. 

O

B C 

LEVEL OF CERTAINTY

A. Available information is not adequate for determination of the level of mineral resource potential.

B. Available information suggests the level of mineral resource potential.

C. Available information gives a good indication of the level of mineral resource potential.

D. Available information clearly defines the level of mineral resource potential.

Abstracted with minor modifications from:

Taylor, R. B., and Steven, T. A., 1983, Definition of mineral resource potential: Economic Geology,

v. 78, no. 6, p. 1268-1270. 

Taylor, R. B., Stoneman, R. J., and Marsh, S. P., 1984, An assessment of the mineral resource potential

of the San Isabel National Forest, south-central Colorado: U.S. Geological Survey Bulletin 1638, p.

40-42. 

Goudarzi, G. H., compiler, 1984, Guide to preparation of mineral survey reports on public lands: U.S.

Geological Survey Open-File Report 84-0787, p. 7, 8.

Cll
GEOLOGIC TIME CHART 

Terms and boundary ages used by the U.S. Geological Survey in this report

EON

Phanerozoic

Proterozoic

Archean 

pre- Arc

ERA

Cenozoic

Mesozoic

Paleozoic

Late Proterozoic

Middle Proterozoic

Early Proterozoic

Late Archean

Middle Archean

Early Archean 

:hean 2

PERIOD

Quaternary

Tertiary

Neogene 

Subperiod

Paleogene 

Subperiod

Cretaceous

Jurassic

Triassic

Permian

Carboniferous 

Periods

Pennsylvanian

Mississippian

Devonian

Silurian

Ordovician

Cambrian

 -(3800?)- -

EPOCH

Holocene

Pleistocene

Pliocene

Miocene

Oligocene

Eocene

Pateocene

Late 

Early

Late 

Middle 

Early

Late 

Middle 

Early

Late 

Early

Late 

Middle 

Early

Late 

Early

Late 

Middle 

Early

Late 

Middle 

Early

Late 

Middle 

Early

Late 

Middle 

Early

 _

AGE ESTIMATES 

OF BOUNDARIES 

(in Ma)

- 0.010 

- 1.7

O A

JO

\J*J

_ KK

- 96

 T3B

one

- ~240

^\J\J

oort

ocn

- 410

^\j\j

- 500

_ ~CTm ~'b/U

J7UU

- 1600

_ ocnn ZOUU

Owl/U

O*TV/U

'Rocks older than 570 Ma also called Precambrian, a time term without specific rank. 

Informal time term without specific rank.

C12