Mineral Resources of the Desatoya Mountains 

Wilderness Study Area, Churchill and 

Lander Counties, Nevada

U.S. GEOLOGICAL SURVEY BULLETIN 1727-A

Chapter A

Mineral Resources of the

Desatoya Mountains Wilderness Study Area,

Churchill and Lander Counties, Nevada

By EDWIN H. McKEE, HARLAN N. BARTON, 

JAMES E. CONRAD, and DAVID A. PONCE 

U.S. Geological Survey

DAVID A. BENJAMIN 

U.S. Bureau of Mines

U.S. GEOLOGICAL SURVEY BULLETIN 1727

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

WEST-CENTRAL 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 Desatoya Mountains Wilderness 

Study Area, Churchill and Lander Counties, Nevada

U.S. Geological Survey Bulletin 1727-A

Bibliography

Supt. of Docs. No.: I 19.3:1727-A

1. Mines and mineral resources Nevada Desatoya

Mountains Wilderness. 2. Desatoya Mountains Wilderness

(Nev.) I. Mckee, Edwin H. II. Geological Survey (U.S.) III.

Series.

QE75.B9 No. 1727-A 622s 87-600283

[TN24.N3] [533'.09793'52]
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 

mineral 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 Desatoya Mountains 

(NV-030-110) Wilderness Study Area, Churchill and Lander Counties, Nevada.

CONTENTS

Summary Al

Abstract 1

Character and setting 1

Identified resources 1

Mineral resource potential 1 

Introduction 2

Area description 3

Previous and present investigations 3 

Appraisal of identified resources 3

Mining and mineral exploration history 3

Reserves and identified resources 5

Recommendations for further work 5 

Assessment of mineral resource potential 5

Geology 5

Geochemical studies 6

Geophysical studies 6 

Mineral and energy resources 7 

References cited 8 

Appendixes

Definition of levels of mineral resource potential and certainty of assessment 11

Resource/reserve classification 12

Geologic time chart 13

FIGURES

1. Index map showing location of the Desatoya Mountains Wilderness Study Area, Churchill and Lander 

Counties, Nevada A2

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

Study Area, Churchill and Lander Counties, Nevada 4

TABLE

1. Claims in and near the Desatoya Mountains Wilderness Study Area 14

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: WEST-CENTRAL NEVADA

Mineral Resources of the

Desatoya Mountains Wilderness Study Area,

Churchill and Lander Counties, Nevada

By Edwin H. McKee, Harlan N. Barton, James E. Conrad, and David A. Ponce, 

U.S. Geological Survey

David A. Benjamin 

U.S. Bureau of Mines

SUMMARY

Abstract

The Desatoya Mountains Wilderness Study Area (NV030-110) encompasses 51,262 acres of the central part of the 

Desatoya Mountains, Churchill and Lander Counties, Nev. Of 

this area, mineral surveys were requested on 43,053 acres 

and were studied for this report. The U.S. Bureau of Mines 

and the U.S. Geological Survey conducted geological, geophysical, and geochemical surveys to assess the mineral 

resources (known) and the mineral resource potential (undiscovered) of the study area. In this report, any reference to the 

Desatoya Mountains Wilderness Study Area refers only to that 

part of the wilderness study area on which the Bureau of Land 

Management requested mineral surveys and is referred to as 

the study area. An areathat includes a tributary of Topia Creek 

on the east edge of the study area is assigned a moderate 

potential for gold and silver resources. In the northern part of 

the study area and in the Rock Creek and Gold Basin claim 

areas a low resource potential for gold and silver is indicated. 

The study area contains no identified mineral resources.

Character and Setting

The study area is in the Desatoya Mountains about 60 mi 

east of Fallon, Nev., and 40 mi west of Austin, Nev. (fig. 1). 

It includes the highest and most rugged parts of these mountains, with topographic relief as much as 3,500 ft between 

Desatoya Peak and the range front to the west. The west side 

of the mountains is precipitous; the eastern side is a dissected 

surface sloping gently to the east. The study area is underlain 

by a thick sequence of rhyolite welded tuffs and intrusive 

rocks mostly of Oligocene and (or) Miocene age (see appendixes for geologic time chart). These volcanic and intrusive

rocks are the products of a volcano that collapsed to form a 

large caldera located in the central part of what is now the 

Desatoya Mountains. This caldera, which formed about 24 

million years ago, was subsequently filled with volcanic 

material before being greatly modified by basin and range 

faulting and by erosion.

Identified Resources

No identified mineral or energy resources exist in the 

study area. Several areas with traces of gold and silver were 

recognized, but these occurrences do not qualify as resources. 

Parts of the study area are in the poorly defined Gold Basin and 

Eastgate mining districts. No mines are in the study area; there 

are seven claim groups or prospects in or within 0.5 mi of the 

study area boundary.

Mineral Resource Potential

An area in the northeastern part of the study area, near 

Topia Creek, has moderate mineral resource potential for gold 

and silver (fig. 2). This potential is indicated by gold and silver 

anomalies in a heavy-mineral concentrate sample and gold 

anomalies in two rock-chip samples.

Three areas have low mineral resource potential for 

gold and silver. These areas are the northern part of the study 

area north of Cold Springs Canyon, an area near the mouth of 

Rock Creek Canyon, and an area east of Carroll Summit. This 

assessment is based on small, scattered geochemical anomalies of gold and silver.

Several drainages in the central and southern parts of the 

study area showed weak anomalies of lead, tin, and bismuth 

from heavy-mineral concentrates from stream sediment.

A1
118000

3»°30' _

39«15'

APPROXIMATE BOUNDARY 

OF

DESATOYA MOUNTAINS

WILDERNESS STUDY AREA

(NV-030-110)

Figure 1. Index map showing location of the Desatoya Mountains Wilderness Study Area, Churchill and Lander 

Counties, Nevada.

These anomalies by themselves do not constitute enough INTRODUCTION

evidence to indicate any mineral resource potential for these

metals, and there is no other geological evidence for any This mineral resource study is a joint effort by the U.S.

resource potential for these metals. Geological Survey and the U.S. Bureau of Mines. Mineral

A2
assessments methodology and terminology were discussed by 

Goudarzi (1984). Identified resources are classified according to the system described by U.S. Bureau of Mines and U.S. 

Geological Survey (1980). See appendix for the definition of 

levels of mineral resource potential, certainty of assessment, 

and classification of identified resources. Studies by the U.S. 

Geological Survey are designed to provide a reasonable 

scientific basis for assessing the potential for mineral resources by determining geologic units and structures, possible 

environments of mineral deposition, presence of geochemical 

and geophysical anomalies, and applicable ore-deposit models. The U.S. Bureau of Mines evaluates identified resources 

at individual mines and known mineralized areas by collecting data on current and past mining activities and through field 

examination of mines, prospects, claims, and mineralized 

areas.

Area Description

The Desatoya Mountains Wilderness Study Area covers 51,262 acres in the central part of the Desatoya Mountains 

in west-central Nevada (fig. 1). Of this area, mineral surveys 

were requested on 43,053 acres by the Bureau of Land 

Management and were studied for this report (fig. 1). The 

terrain is rugged and topographic relief is as much as 3,500 ft. 

Elevation ranges from 9,973 ft at Desatoya Peak to about 

5,400 ft in Edwards Creek Valley at the north end of the area. 

The climate is semiarid and the vegetation is typical of the 

transition climatic zone.

The Desatoya Mountains are about 60 mi east of Fallon, 

Nev., and 40 mi west of Austin, Nev. The study area is 

bounded on the south by Nevada Highway 2 and by U.S. 

Highway 50 along the northwest corner of the area. 

Unimproved dirt roads reach the mouths of most of the 

canyons on the west side of the study area, and a few fourwheel-drive trails from the north, east, and south reach high 

points in the area.

Previous and Present Investigations

A geologic map of the Desatoya Wilderness S tudy Area 

was published by McKee and Conrad (1987). The eastern part 

of the area is briefly described in a report on the geology and 

mineral deposits of Lander County, Nev. (Stewart and 

McKee, 1977), and the western part in a report on the geology 

and mineral deposits of Churchill County, Nev. (Willden and 

Speed, 1974). Volcanic rocks collected from the study area 

have been radiometrically dated and are discussed in reports 

by McKee and Stewart (1971) and Willden and Speed (1974). 

Parts of the study area are included in the poorly defined Gold 

Basin and Eastgate mining districts. Both districts are briefly 

described in a report by Lincoln (1923), and more complete 

information about them is included in reports by Willden and 

Speed (1974) and Stager (1977). A report on the mining 

districts in Churchill County, including the western part of the

study area, is in Vanderburg (1940). Later reconnaissance 

geophysical and geochemical studies that touch on all or part 

of the study area include: aeromagnetic maps (U.S. Geological Survey, 1971 and 1972); a Bouguer gravity map (Erwin 

and Bittleson, 1977); aerial radiometric and magnetic surveys 

(Geodata International Inc., 1979); and geochemistry of 

stream sediments (U.S. Bureau of Land Management, Great 

Basin G.E.M. Joint Venture, 1983a, b). Benjamin (1987) 

studied mines and prospects in and near the wilderness study 

area.

The U.S. Geological Survey carried out field investigations in the study area in the summers of 1985 and 1986. The 

work included geologic mapping, geochemical sampling, and 

geophysical (gravity) studies. Geochemical samples were 

collected from all stream drainages to obtain information 

about mineral suites and trace-element signatures associated 

with mineralizing systems.

The U.S. Bureau of Mines conducted a search of 

Churchill and Lander County mining records, and U.S. Bureau of Mines and U.S. Bureau of Land Management mining 

claim and mineral-lease records in 1984. Field studies in 1985 

consisted of examination and geochemical sampling of areas 

of altered rock and those prospects and claims that could be 

found. Geochemical results for gold and silver were acquired 

by fire assay-inductively coupled plasma techniques combined with analyzed for 40 elements by semiquantitative 

spectrographic techniques. Zeolites were analyzed by X-ray 

diffraction. Detailed information and sample results are 

available from the Bureau of Mines, Western Field 

Operations Center, E. 360 Third Avenue, Spokane, WA 

99202.

APPRAISAL OF IDENTIFIED RESOURCES

By David A. Benjamin 

U.S. Bureau of Mines

Mining and Mineral Exploration History

Little mining activity has occurred in the Desatoya 

Mountains. Bureau of Land Management and historical 

government mining claim records indicate seven areas of 

claims are in or within 0.5 mi of the study area (fig. 2, Nos. 1- 

7; table 1). Historical mining claim records indicate several 

other claims may have been staked in or near the study area, 

but the location information is too vague for field identification. Descriptions of minor prospects and mineralized sites 

from which geochemical samples were gathered are listed in 

Benjamin (1987).

The first claims in the study area were staked in 1907 in 

the area north west of Cold Springs Canyon (table 1; fig. 2,No. 

3). The Cold Springs claim area has undergone a small 

amount of exploration work up to the present. The most recent 

exploration work has been done by Phelps Dodge Corporation

A3
]17°42'

39"28'

Figure 2. Mineral resource 

potential and generalized geology 

of the Desatoya Mountains 

Wilderness Study Area, Churchill 

and Lander Counties, Nevada. 

Geology from McKee and Conrad 

(1987).

39° 15' -

APPROXIMATE BOUNDARY 

OF

DESATOYA MOUNTAINS 

WILDERNESS STUDY AREA

A4
EXPLANATION

Area with moderate resource potential 

Area with low resource potential

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

of assessment

Commodities 

Ag Silver 

Au Gold

[ ] Deposit types 

1 Epithermal gold- and silver-bearing quartz veins and silicified zones

Correlation of map units

Holocene or Pleistocene - QUATERNARY

- Miocene and (or) Oligocene - TERTIARY

Q a

Qoa

Tm

Td

T t

Tr

T c

T a

C'

1

2

3

4

5

6

7

Description of map units

Alluvium, colluvium, and talus (Holocene or Pleistocene)-Mostly

stream sand and gravel, intermontane fans 

Older alluvium (Holocene or Pleistocene) Nonlithified, dissected

alluvial fans 

Tuff of Milkhouse Creek (Miocene and (or) Oligocene) Welded ashflow tuff 

Tuff of Desatoya Peak (Miocene and (or) Oligocene) Welded ashflow tuff 

Tuffaceous sedimentary rocks, rhyolite tuffs, and lava flows (Miocene

and (or) Oligocene) Soft, white to gray ashy sandstone, \vhite to

pink, crystal-rich welded tuff, and light-colored rhyolite lava flows.

All units are lenticular on scale of 1 mi or less 

Rhyolite lava flows (Miocene and (or) Oligocene) Flow-banded, pink

to gray lava flows and local ash flows 

Rhyolite of Campbell Creek (Miocene and (or) Oligocene) Densely

welded white to lavender tuff, lava flows and intrusive rocks.

Crystal-poor rhyolite containing phenocrysts of quartz, plagioclase, and sanidine 

Andesite lava flows (Miocene and (or) Oligocene) Platy to blocky

splitting, pink, red, and brown andesite to dacite lava flows

containing plagioclase and alkali feldspar 

Contact-Dashed where approximately located 

Normal fault-Ball and bar on downthrown side 

Trace of cooling breaks in tuff of Desatoya Peak 

Claim See table 1 for description

Cheyenne claims

Last Chance claims

Cold Springs claim area

Rollo claims

Rock Creek claims

Gold Basin claim area

Great Basin Resources claim area

Figure 2. Continued.

and AS ARCO. In 1911-12, the Cedar Creek area (the Cheyenne claims, fig. 2, No. 1) and the Gold Basin claims area (fig. 

2, No. 6) were first explored. The Gold Basin claims area had 

minor gold and silver production in 1911-12 and 1940-41. 

The Cheyenne claims in the Cedar Creek area were restaked 

in 1985. In 1915 the Rock Creek claims (fig. 2, No. 5) were 

staked; they have undergone minor surface exploration. In 

1919, the Last Chance claims (fig. 2, No. 2) were staked near 

the divide between Cold Springs Canyon and Cedar Creek. 

This area was explored using small surface pits and underground tunnels. In 1921 the Rollo claims (fig. 2, No. 4) were 

staked and explored by minor surface workings. The Great 

Basin Resources claim area (fig. 2, No. 7) was staked in 1981 

in the southwest corner of the study area; no workings are on 

these claims.

Reserves and Identified Resources

No mineral or energy resources were identified within 

or adjacent to the study area.

Sand and gravel deposits suitable for construction are 

present in the study area. Because similar materials of equal 

or better quality are abundant closer to local markets, and the 

probable costs of mining exceed the present market value of 

these materials, their future development is highly unlikely.

Recommendations for Further Work

Electrical resistivity studies along four zones that 

include the Cheyenne, Last Chance, Cold Springs, and Gold 

Basin Resources claims might help to determine the presence 

of buried metal-bearing deposits. Further surface 

geochemical sampling is needed at: (1) Rock Creek claims, 

(2) east of the Great Basin Resource claim area, and (3) several 

sites in the northern part of the study area (Benjamin, 1987). 

This sampling would augment initial geochemical sampling 

(Benjamin, 1987) and could serve as an indicator of 

unrecognized gold and silver deposits.

ASSESSMENT OF MINERAL RESOURCE 

POTENTIAL

By Edwin H. McKee, Harlan N. Barton, 

James E. Conrad, and David A. Ponce 

U.S. Geological Survey

Geology

Most of the rocks in the Desatoya Mountains Wilderness Study Area are late Oligocene and (or) early Miocene 

rhyolite welded ash-flow tuffs; lava flows and intrusive rocks 

of the same age are present in smaller amounts. These 

rhyolitic rocks intrude and overlie a thick sequence of andesite 

lava flows of Oligocene and (or) Miocene age that forms the

A5
basement in the area. The rhyolitic welded tuffs, lava flows, 

and intrusive bodies erupted from a late Oligocene and (or) 

early Miocene volcano located in the southeastern part of the 

study area. This volcano developed into a collapse caldera 

early in its eruptive period and was greatly modified by 

subsequent basin and range faulting and by later erosion. All 

physiographic and tectonic aspects of the caldera are obscured 

by the later tectonic and erosional events.

The eruptive center and caldera are recognized by the 

large volumes of massive welded tuff and numerous small 

intrusions that are exposed in the southeastern part of the study 

area. North of this area, the welded tuffs display welldeveloped cooling breaks and are stratified. The intracaldera 

and out-flow facies of the welded tuffs from this volcanic 

center define the general location of the caldera.

Andesite lava flows and flow breccias are the oldest 

rocks in the study area. The base of this sequence of andesites 

is not exposed in the study area but the sequence probably 

unconformably overlies metavolcanic and metasedimentary 

rocks of Mesozoic age, as is the case with other late Tertiary 

rocks in central Nevada. The andesitic rocks are hues of 

brown and red and are noticeably darker than the rhyolitic 

rocks in the region. The lava flows are thin and platy to blocky 

splitting. Phenocrysts of plagioclase and alkali feldspar are 

visible in hand specimen and thin section. Interbedded with 

the lava flows are breccias consisting of angular fragments of 

dark andesite in a softer granular matrix. A potassium-argon 

age determined on a whole rock sample of andesite from Park 

Canyon is about 25 Ma.

The oldest rocks erupted from the Desatoya Mountains 

volcanic complex are rhyolite ash-flow tuffs, lava flows, and 

intrusive rocks called the rhyolite of Campbell Creek (McKee 

and Conrad, 1987). North of the highway at Carroll Summit 

and near Campbell Creek the unit consists mostly of rhyolite 

domes. Along the east side of the Desatoya Mountains, the 

rhyolite of Campbell Creek is massive welded tuff with no 

cooling breaks. Because of the great thickness (at least 500 ft 

thick) and the massive, highly compacted nature of this tuff, 

it is likely that much of it was deposited in a basin, probably 

a caldera that formed after the first ash-flow eruptions. The 

welded tuff has strong eutaxitic texture and is white, pink, or 

lavender with sparse crystals of quartz, sanidine, and plagioclase. Potassium-argon age determinations of sanidine from 

several localities indicate that the rhyolite of Campbell Creek 

is about 25 Ma.

The tuff of Desatoya Peak (McKee and Conrad, 1987) 

is the second and most voluminous ash-flow tuff erupted from 

the Desatoya Mountains volcanic center. This welded tuff 

forms most of the mountains from Park Canyon in the southern part of the study area to Edwards Creek north of the area. 

Spectacular exposures of this tuff form the cliffs along the 

west side of the range, where more than 3,500 ft of tuff is 

exposed in vertical section. The tuff consists of at least two 

ash-flow sequences separated in places by a lenticular sequence of tuffaceous sedimentary rocks, air-fall tuffs, volcanic breccias, and lava flows. These intervening rocks can be 

as much as several hundred ft thick and can be traced for about 

10 mi before they pinch out. In the northern part of the 

Desatoya Mountains, about 5 mi northeast of the study area, 

the tuff of Desatoya Peak is less than 500 ft thick, has sharp 

upper and lower contacts, and is stratified. This thin, layered 

tuff is the outflow facies of the ash-flow sheet. The thick and 

massive tuff in the study area is the intracaldera facies of the 

same ash-flow sheet. The tuff of Desatoya Peak is pink to 

brown, densely welded, crystal-rich, lithic welded tuff. Phenocrysts are quartz, plagioclase, sanidine, and biotite; they are 

in a eutaxitic groundmass of devitrified glass shards. Chemical analysis suggests this tuff is a low-silica rhyolite or quartz 

latite.

The youngest volcanic rock unit in the study area is a 

thin (less than 70 ft) welded tuff called the tuff of Milkhouse 

Creek (McKee and Conrad, 1987). This tuff forms caps on 

peaks and spurs in the eastern part of the study area near 

Milkhouse Creek. Its contact with underlying units is sharp 

and probably unconformable; in places some sedimentary 

rock separates the tuff from the underlying rock unit. The tuff 

of Milkhouse Creek is pink to lavender, densely welded, 

crystal-poor tuff with scattered phenocrysts of quartz, sanidine, and plagioclase. Eutaxitic texture is strongly developed.

Sedimentary rocks comprise only a small part of the 

rocks in the study area. The oldest sedimentary rocks are 

lenticular strata that are found with lava flows and air-fall tuffs 

beneath the tuff of Desatoya Peak. Similar strata are present 

between the two major cooling units of the tuff of Desatoya 

Peak. These fine-grained, tuffaceous sandstones and 

siltstones are white to gray, thin bedded and fissile. Sedimentary features such as ripple marks and very small scale cross 

bedding indicate that they were deposited in water. Most of 

the individual beds can be traced for only a few tens on feet and 

entire sedimentary sequences pinch out in distances of about 

1 mi.

In the southwestern part of the study area, a thick 

accumulation of coarse, poorly sorted, nonlithified alluvial 

fan material forms a series of subdued hills. These old alluvial 

fans are presently being dissected by west-flowing drainages 

and debris from the fans is being redeposited in active modern 

alluvial fans.

Geochemical Studies

A reconnaissance geochemical study consisted of 

analysis and evaluation of stream-sediment samples and 

heavy-mineral concentrate samples from stream-sediment 

from 116 sites. Samples were analyzed for 31 elements by a 

six-step semiquantitative emission-spectrographic method 

(Grimes and Marranzino, 1968). Details on sample preparaA6
tion and analysis are in Barton and others (1987).

Areas or drainages with anomalous concentrations of 

metallic or metal-related elements were identified by comparing all values from the data set of 116 samples and on 

enrichment related to crustal abundance.

Geochemical anomalies for one or more elements were 

detected in twelve widely scattered drainages. Most of these 

anomalies are small and involve only a single element. A 

heavy-mineral concentrate sample from a tributary to Topia 

Creek in the northeastern part of the study area contains 100 

parts per million (ppm) gold and 100 ppm silver. Two rockchip samples from this area were analyzed by fire assayinduced coupled plasma techniques and found to contain 

0.079 and 0.252 ppm gold and nil and 0.42 ppm silver 

(Benjamin, 1987). A stream-sediment sample from a tributary to Cedar Creek contains 1.5 ppm silver. In the southern 

part of the study area six drainages have anomalies of tin 

ranging from 70 to 300 ppm. Three drainages in the central 

part of the study area have anomalous lead concentrations of 

between 500 and 1500 ppm. Anomalous concentrations of 

bismuth accompanied tin in one drainage and anomalous 

concentrations of bismuth and copper were detected in another drainage.

Geophysical Studies

Geophysical investigations of the study area include 

aerial gamma-ray, gravity, and aeromagnetic techniques. 

Interpretation of aerial gamma-ray maps provides estimates 

of the apparent surface concentrations of potassium, equivalent uranium, and equivalent thorium. The available maps 

were compiled at a scale of 1:1,000,000 as part of the National 

Uranium Resource Evaluation program (Geodata International Inc., 1979). The Desatoya Mountains Wilderness 

Study Area has an overall moderate radioactivity with values 

of 2 to 3 percent potassium, 4 to 6.5 ppm equivalent uranium, 

and 11 to 16 ppm equivalent thorium. These values are typical 

of terrains composed mostly of rhyolitic rock. There are no 

anomalies within the boundaries of the study area nor in the 

immediate vicinity (J.S. Duval, written commun., 1985).

Bouguer gravity anomaly maps of the study area and 

vicinity were prepared at scales of 1:250,000 and 1:62,500 

using existing data (Erwin and Bittleson, 1977) supplemented 

by recent data collected by the U.S. Geological Survey (R.N. 

Harris and J.M. Glen, unpub. data, 1986). Gravity data 

coverage is good throughout the study area, with measurements spaced at intervals of 3 mi or less in the Desatoya 

Mountains.

The southwestern part of the Desatoya Mountains is 

characterized by a complex subcircular gravity low of about 

30 mGal. This probably represents a thicker section of 

volcanic rocks and may be related to a hypothesized caldera 

in the southern Clan Alpine and Desatoya Mountains (Riehle

and others, 1972). The northern part of the Desatoya Mountains is characterized by a narrow north-trending gravity high 

of about 40 mGal that extends northward over Edwards Creek 

Valley. The highest values of the elongate gravity high 

coincide with exposures of the tuff of Desatoya Peak. The 

extension of the gravity high over Edwards Creek Valley may 

represent a pediment of moderately dense rhyolitic rocks at 

shallow depth. Alternatively, this high may represent fairly 

dense Mesozoic rocks buried at intermediate depths below the 

east half of the Desatoya Mountains.

A total-intensity aeromagnetic survey of the south end 

of the study area was flown at constant barometric elevation 

of 9,000 ft above sea level with an east-west flightline spacing 

of 1 mi (U.S. Geological Survey, 1971), and the remainder of 

the study area was flown at constant barometric elevation of 

9,000 ft above sea level with an east-west flightline spacing of 

2 mi (U.S. Geological Survey, 1972). The aeromagnetic map 

of the study area is complex and anomalies generally reflect 

relatively magnetic Tertiary volcanic rocks.

The most prominent magnetic feature of the study area 

is a 400-nT (nanoteslas) magnetic anomaly near Desatoya 

Peak. The crescent-shaped anomaly covers most of the study 

area and correlates with the tuff of DesatoyaPeak. About 2 mi 

south of the southeast border of the study area, small outcrops 

of granitic rocks underlie a 150-nT anomaly.

MINERAL AND ENERGY RESOURCES

Data from geologic studies, geochemical sampling, and 

examination of prospects and areas of altered rock recognized 

by the presence of limonite staining and (or) silicification 

suggest that there is moderate and low potential for resources 

of gold and silver in parts of the Desatoya Mountains Wilderness Study Area. Geologic mapping and aeromagnetic data 

indicate that the Desatoya Mountains are comprised of a thick 

accumulation of crystal-rich, rhyolite welded tuff and crystalpoor rhyolite domes. The range is characterized by massive 

outcrops of unaltered rhyolitic rock; no prevailing fault system or throughgoing structures were mapped, and alteration is 

not widespread or pervasive. Locally, small quartz veins and 

silicified or limonite-stained outcrops indicate that some 

alteration and mineralization has taken place after emplacement of the volcanic rocks. Geochemical sampling of stream 

sediments and altered rock confirms the presence of scattered 

anomalous concentrations of various metals. Gold, silver, tin, 

and copper in rhyolitic host rock, associated with quartz veins 

and local alteration and silicification, suggests epithermal 

activity. The lack of clearly discernible faults, the scattered 

and local nature of veins, alteration and silicification, and the 

dispersed geochemical anomalies, suggest that this epithermal system was not large and that it did not produce large areas 

of mineralized rock. Because of the weak nature of the

A7
alteration the most useful guide to areas of mineral resource 

potential in the Desatoya Mountains is the location of geochemical anomalies.

The areas of moderate and low resourcepotential shown 

on figure 2 are located on the basis of geochemical anomalies. 

One tributary to Topia Creek yielded anomalous concentrations of gold and silver from heavy-mineral concentrates and 

two rock chip samples from 0.25 to 0.5 mi east of this drainage 

yielded gold anomalies. The area that includes the Topia 

Creek tributary has moderate resource potential for gold and 

silver, certainty level B, although no source or site of the 

mineralization was recognized in the field. The part of the 

study area north of Cold Springs Canyon, the west-central 

part, and the southeast corner of the study area all yielded 

scattered rock samples with minor amounts of gold, silver, 

and copper. These areas are assigned a low resource potential 

for gold and silver, certainty level C (fig. 2).

There is no potential for sand and gravel resources 

beyond the known occurrences within the study area. An 

assumption that is part of this conclusion is that the known 

occurrences extend to depth in approximately uniform quality.

Geologic data indicate a low probability for the occurrence of oil and gas in the Cenozoic rocks of the study area. 

Evidence for hydrocarbon potential is negligible; the volcanic 

rocks and fluviatile sedimentary strata immediately underlying the study area might include suitable reservoir rocks, but 

lack hydrocarbon source beds. Because of widespread pervasive geothermal heating, the Desatoya Mountains and surrounding areas are considered to have no potential for petroleum resources (Sandberg, 1983).

The wilderness study area has no geothermal energy 

resource potential. There is no evidence of geothermal 

activity in or near the study area.

REFERENCES CITED

Barton, H.N., Day, Gordon, and Malcolm, M.J., 1987, Analytical results and sample locality map for heavy-mineral-concentrate and stream-sediment samples from 

the Desatoya Mountains Wilderness Study Area, 

Churchill and Lander Counties, Nevada: U.S. Geological Survey Open-File Report [in press].

Benjamin, D.A., 1987, Mineral resources of the Desatoya 

Mountains Study Area, Churchill and Lander Counties, Nevada: U.S. Bureau of Mines Open-File 

Report, MLA 70-86, 28 p.

Erwin, J.W., and Bittleson, E.W., 1977, Bouguer gravity map 

of Nevada, Millett sheet: Nevada Bureau of Mines 

and Geology Map 53, scale 1:250,000, 1 sheet.

Geodata International, Inc., 1979, Aerial radiometric and 

magnetic survey, Millett national topographic map, 

Nevada: Prepared for the U.S. Department of Energy, Grand Junction, Colorado, GJBX-154(79), 62 

PGoudarzi, G.H., 1984, Guide to preparation of mineral survey 

reports on public lands: U.S. Geological Survey 

Open-File Report 84-787, 51 p.

Grimes, D.J., and Marranzino, A.P., 1968, Direct-current arc 

and alternating-current spark emission spectragraphic field methods for the semiquantitative analysis of geologic materials: U.S. Geological Survey 

Circular 591, 6 p.

Lincoln, F.C., 1923, Mining districts and mineral resources of 

Nevada: Reno, Nev., Newsletter Publishing Company, 20 p.

McKee, E.H., and Conrad, J.E., 1987, Geologic map of the 

Desatoya Mountains Wilderness Study Area, 

Churchill and Lander Counties, Nevada: U.S. Geological Survey Miscellaneous Field Studies Map MF1944, scale 1:62,500.

McKee, E.H., and Stewart, J.H., 1971, Stratigraphy and potassium-argon ages of some Tertiary tuffs from Lander 

and Churchill Counties, Central Nevada: U.S. Geological Survey Bulletin 1311-B, 28 p.

Riehle, J.R., McKee, E.H., and Speed, R.C., 1972, Tertiary 

volcanic center, west-central Nevada: Geological 

Society of America Bulletin, v. 83, p. 1383-1396.

Sandberg, C.A., 1983, Petroleum potential of wilderness lands 

in Nevada: U.S. Geological Survey Circular 902-H, 

p. H1-H11.

Stager, H.K., 1977, Mineral Deposits, in Geology and mineral 

deposits of Lander County, Nevada: Nevada Bureau 

of Mines and Geology Bulletin 88, pt. 2, p. 60-102.

Stewart, J.H., and McKee, E.H., 1977, Geology, in Geology 

and mineral deposits of Lander County, Nevada: 

Nevada Bureau of Mines and Geology Bulletin 88, pt. 

1,p. 1-59.

U.S. Bureau of Land Management Great Basin G.E.M. Joint 

Venture, 1983a, Geochemical sample collection and 

chemical analyses for WSA's NV-030-102 and NV030-110, Nevada region, U.S. Bureau of Land Management, Denver Service Center, Denver, Colo., 33

P-

__1983b, Desatoya Mountains GEM resources area (GRA 

No. NV-06) technical report, prepared for U.S. Bureau of Land Management, Denver Service Center, 

Denver, Colo., 30 p.

U.S. Bureau of Mines and U.S. Geological Survey, 1980, 

Principles of a resource/reserve classification for 

minerals: U.S. Geological Survey Circular 831, 5 p.

U.S. Geological Survey, 1971, Aeromagnetic map of parts of 

the Tonopah and Millett 1° by 2° quadrangles, Nevada: U.S. Geological Survey Geophysical Investigations MapGP-752, scale 1:250,000, 1 sheet.

__1972, Aeromagnetic map of parts of the Lovelock, Reno, 

and Millett 1 by 2 degree quadrangles: U.S. Geological Survey Open-File Report 72-386, scale 

1:250,000, 1 sheet.

Vanderburg, W.O., 1940, Reconnaissance of mining districts 

in Churchill County, Nevada: U.S. Bureau of Mines 

Information Circular 7093, 57 p.

Willden, Ronald, and Speed, R.C., 1974, Geology and mineral 

deposits of Churchill County, Nevada: Nevada Bureau of Mines and Geology Bulletin 83, 95 p.

A8
APPENDIXES

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 permissive. 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 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 occurence, where interpretations of 

data indicate a high degree of likelihood for resource accumulation, where data supports 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

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.

A11
RESOURCE/RESERVE CLASSIFICATION

IDENTIFIED RESOURCES

Demonstrated

Measured Indicated

Inferred Probability Range

Hypothetical Speculative

ECONOMIC

MARGINALLY 

ECONOMIC

SUBECONOMIC

Reserves Inferred 

Reserves

I

Marginal 

Reserves

Inferred 

Marginal 

Reserves

Demonstrated

Subeconomic

Resources

Inferred

Subeconomic

Resources

Major elements of mineral resource classification, excluding reserve base and inferred reserve base. Modified from U.S. Bureau of Mine? 

and U.S. Geological Survey, 1980, Principles of a resource/reserve classification for minerals: U.S. Geological Survey Circular 831, p. 5.

A12
GEOLOGIC TIME CHART 

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

EON

Phanerozoic

Proterozoic

Archean 

pre - Ar

ERA

Cenozoic

Mesozoic

Paleozoic

Late Proterozoic

Middle Proterozoic

Early Proterozoic

Late Archean

Middle Archean

Early Archean 

chean 2

PERIOD

Quaternary

Neogene

Subperiod

Tertiary

Paleogene 

Subperiod

Cretaceous

Jurassic

Triassic

Permian

Pennsylvanian 

Carboniferous

Mississippian

Devonian

Silurian

Ordovician

Cambrian

 -(3800?)- -

.EPOCH

Holocene

Pleistocene

Pliocene

Miocene

Oligocene

Eocene

Paleocene

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

«% ji

oo

UU 

- RK

- 96

- I'M100

«)AC

- -240

&0W

OOU

- %0 OuU

- 410

A1C

9UU

_ A, CT/M

- onn

icnn

- 2500

ouuu 

 14JV1

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

Informal time term without specific rank.

A13
TABLE 1. Claims in and near the Desatoya

[nil, element not detected in sample; detection limits for

Location 

(fig. 2)

Name Summary

Cheyenne claims

Last Chance claims

Cold Springs claim 

area

Rollo claims

Rock Creek claims

Gold Basin claim 

area

Area first claimed in 1911-12 (16 claims in 

all). Mr. Stan Maestretti of Austin, Nev. 

restaked the area in 1985 as the Cheyenne 

claims. A N. 60° W.-trending zone of 

silicified, argillized breccia containing 

minor quartz veins is in rhyodacite tuff. 

Zone extends for at least 4,000 ft along 

strike.

No claims filed in the area since original 

claims in 1919. A N. 60° W.-trending shear 

zone that locally contains quartz veins cuts a 

rhyolite tuff. Many parts of zone contain 

fresh-looking tuff. Zone is irregular in 

shape both parallel and perpendicular to 

strike. Zone is as thick as 400 ft and 

extends for at least 1,200 ft along strike.

Area first claimed in 1907. In the 1950's 

area was restaked as the Oroplata claims by 

Mr. Gale Peer of Austin, Nev., who drove 2,000 

ft of adits and drifts, 400 ft of shaft, and 

performed surface stripping with a bulldozer. 

From 1979 to 1985 minor exploration work was 

undertaken by Phelps Dodge and ASARCO, Inc. 

No production is recorded. A large silicified 

breccia zone in rhyolite tuffs trends N. 20° 

to 80° W. through the area. Breccia zone does 

not appear to extend into study area.

Claims originally staked in 1921, but no 

claims staked in area since then. N. 45° to 

60° W.-striking zones of alteration area in 

rhyolite tuff. Zones are poorly defined in 

outline, as wide as 100 ft, and several 

hundred ft long. Alteration consists of 

argillization, bleaching, iron oxide staining, 

and minor quartz veining.

Area first staked in 1915; no claims staked in 

the area since 1928. A N. 80° E.-striking 

zone of strongly silicified rhyolite with 

sparce quartz veinlets trends through area. 

Zone has strong iron oxide staining on 

fracture surfaces. Zone is at least 20 ft 

wide.

Since early 1970's the Thunder claims have 

covered area (Mr. Charles Winrod and Mr. Stan 

Maestretti, Austin, Nev., owners). Country 

rock in area is rhyolite ash-flow tuff. Rock 

in mined area bleached, argillized, and 

silicified. Areas of brecciation with 

moderate to strong iron oxide staining. 

Individual zones of alteration trend N. 40° W. 

to N. 20° E. Mineral deposits do not appear 

to extend into the study area.

Great Basin County rock in area is Tertiary rhyolite ashResources claim fall tuff, and intrusive and extrusive 

area rhyolite. No evidence of mining activity or 

mineralized areas were observed.

A14
Mountains IVi/derness Study Area

gold and silver 0.007 and 0.3 ppm, respectively]

Workings Sample data

One 10-ft shaft, four 

trenches, and 14 pits.

Twelve chip samples from veins, breccia zones, and 

country rock contained nil to 0.20 ppm gold and nil 

to 11.55 ppm silver. Eight grab samples from dump 

material contained nil to 0.25 ppm gold and 0.54 

ppm to 8.83 ppm silver.

One 50 ft adit, one trench, 

and four pits.

Three chip samples from the adit contained 0.04 to 

0.088 ppm gold and 2.10 to 12.02 ppm silver. Seven 

chip samples from workings and outcrop contained 

nil to 0.06 ppm gold and nil to 9.16 ppm silver. 

Four grab samples from dump material contained 

0.018 to 0.09 ppm gold and 0.4 to 8.54 ppm silver.

Several shafts, adits, pits, 

trenches, and drill pads.

Four chip samples taken from quartz vein material 

and silicified tuff contained from 0.07 to 2.71 ppm 

gold and 2.55 to 31 ppm silver. Four dump grab 

samples contained from 0.03 to 4.13 ppm gold and 

0.5 to 80 ppm silver.

Two shallow pits and a 10-ft 

adit.

One chip sample from the adit contained 0.01 ppm 

gold and nil silver. One dump grab sample from a 

pit contained 0.036 ppm gold and nil silver. One 

float sample contained nil gold and 0.92 ppm 

silver.

Shallow pit 400 ft west of 

study area boundary.

Grab sample of dump material contained 0.11 ppm 

gold and 25.32 ppm silver. Two outcrop chip 

samples contained 0.045 and 0.047 ppm gold and 1.82 

and 3.86 ppm silver.

During 1911-12 a 250-ft-deep 

shaft was sunk with 700 ft of 

underground workings, producing 751 oz gold and 8,677 oz 

silver. During 1940-41 1,384 

short tons were produced with 

231 oz gold and 1,409 oz 

silver recovered. Presently 

the workings consist of four 

bulldozer cuts, a caved shaft, 

and an adit.

Four chip samples from altered rock exposed both in 

workings and in outcrop; contains 0.103 to 0.19 ppm 

gold and 1.14 to 4.82 ppm silver.

None Fifteen chip and one grab (float) samples were 

taken. Thirteen samples contained nil gold and 

silver. One sample contained 0.02 ppm gold and nil 

silver. Three of the 13 samples were analyzed for 

uranium; no anomalous values were obtained. Three 

samples were also inspected for zeolites; none were 

detected. Two samples of rhyolite taken several 

hundred ft east of the claims contained 0.03 and 

0.10 ppm gold and nil silver. A15


GPO 785-048/77400

mm