Mineral Resources of the 

Lime Canyon Wilderness Study 

Clark County, Nevada

U.S. GEOLOGICAL SURVEY BULLETIN 1 730-D

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Chapter D

Mineral Resources of the

Lime Canyon Wilderness Study Area,

Clark County, Nevada

By JAMES G. EVANS, GARY A. NOWLAN, and 

JOSEPH S. DUVAL 

U.S. Geological Survey

RICHARD A. WINTERS 

U.S. Bureau of Mines

U.S. GEOLOGICAL SURVEY BULLETIN 1730

MINERAL RESOURCES OF WILDERNESS STUDY AREAS: 

SOUTHERN NEVADA
DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, JR., Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Any use of trade, product, or firm names

in this publication is for descriptive purposes only

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

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1990

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 Lime Canyon Wilderness study area, Clark 

County, Nevada / by James G. Evans ... [et al.]

p. cm. (U.S. Geological Survey bulletin ; 1730-D)

Includes bibliographical references (p. ).

Supt. of Docs, no.: I 19.3: 1730-D

1. Mines and mineral resources Nevada Lime Canyon Wilderness. 

2. Lime Canyon Wilderness (Nev.) I. Evans, James George, 1938- 

II. Series.

QE75.B9 no. 1730-D 557.3 s dc20 90-3673 

UN24.N3] [553'.09793'13] CIP
STUDIES RELATED TO WILDERNESS

Bureau of Land Management Wilderness Study Areas

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 the Lime 

Canyon Wilderness Study Area (NV-050-231), Clark County, Nevada.

CONTENTS

Summary Dl

Abstract Dl

Character and setting Dl

Identified mineral resources Dl

Mineral resource potential Dl 

Introduction Dl

Area description D2

Previous and present investigations D3 

Appraisal of identified resources D3

Methods D3

Mining history D3

Mineral resources D4 

Assessment of mineral resource potential D5

Geology D5

Geochemical studies D8

Geophysical studies D9

Mineral and energy resource potential D9 

References cited DID 

Appendixes D12

Definition of levels of mineral resource potential and certainty of 

assessment D14

Resource/reserve classification D15

Geologic time chart D16

FIGURES

1. Index map showing location of Lime Canyon Wilderness Study Area, Clark 

County, Nevada D2

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

Canyon Wilderness Study Area, Clark County, Nevada D6

Contents

Mineral Resources of the

Lime Canyon Wilderness Study Area,

Clark County, Nevada

By James G. Evans, Gary A. Nowlan, and Joseph S. Duval 

U.S. Geological Survey

Richard A. Winters 

U.S. Bureau of Mines

SUMMARY 

Abstract

At the request of the Bureau of Land Management, the 

Lime Canyon Wilderness Study Area, comprising approximately 34,680 acres, was evaluated for mineral resources and 

mineral resource potential. Throughout this report, "wilderness study area" and "study area" refer to the 34,680 acres for 

which a mineral survey was requested. The U.S. Geological 

Survey and the U.S. Bureau of Mines conducted geologic, 

geochemical, and geophysical surveys to assess the identified 

mineral resources (known) and mineral resource potential 

(undiscovered) of the study area. Fieldwork for this report 

was carried out in 1987. The study area contains a 44-million-short ton inferred subeconomic resource of gypsum. 

Carbonate rock underlies 20 square miles of the study area, 

and sand and gravel covers 16 square miles of the study area. 

The eastern part of the study area has low potential for barite, 

copper, gold, lead, silver, and zinc resources. Nearly half of 

the study area has low potential for oil and gas. There is no 

potential for geothermal resources.

Character and Setting

The Lime Canyon Wilderness Study Area is 2 mi 

east of the Overton Arm of Lake Mead and 45 mi east of 

Las Vegas, Nev. (fig. 1). The study area's total relief of 

about 2,600 ft is expressed largely by several closely 

spaced ridges oriented generally north-south and several 

canyons, the deepest of which is Lime Canyon. The study 

area is underlain by Proterozoic granite and gneiss that is

Manuscript approved for publication, April 27, 1990

partly covered by sedimentary rocks of Paleozoic, Mesozoic, and Tertiary age and by alluvium that is as young as 

Quaternary (see "Appendixes" for geologic time chart). 

Numerous faults cut the rocks of the study area.

Identified Mineral Resources

The wilderness study area contains an estimated 44- 

million-short ton (st) inferred subeconomic resource of 

gypsum. Carbonate rock underlies more than 20 mi2 of the 

study area, and sand and gravel covers 16 mi2 in the western part of the study area. The high-volume, low-unitvalue commodities of the study area including gypsum, 

limestone, dolomite, and sand and gravel are not considered 

economic because the same commodities are available 

nearer to existing markets or railways.

Mineral Resource Potential

Most of the eastern part of the Lime Canyon Wilderness Study Area has low resource potential for barite, 

copper, gold, lead, silver, and zinc (fig. 2). Nearly half of 

the study area (underlain by unit TMzFfe, fig. 2) has low resource potential for oil and gas. The study area has no 

potential for geothermal resources.

INTRODUCTION

This mineral survey was requested by the U.S. 

Bureau of Land Management and is the result of a cooperative effort by the U.S. Geological Survey and the U.S.

Mineral Resources of the Lime Canyon Wilderness Study Area, Clark County, Nevada D1
Bureau of Mines. An introduction to the wilderness review 

process, mineral survey methods, and agency responsibilities was provided by Beikman and others (1983). 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. Identified resources are classified according to a 

system that is a modification of that described by 

McKelvey (1972) and U.S. Bureau of Mines and U.S. 

Geological Survey (1980). U.S. Geological Survey studies 

are designed to provide a scientific basis for assessing the 

potential for undiscovered mineral resources by determining geologic units and structures, possible environments of

mineral deposition, presence of geochemical and geophysical anomalies, and applicable ore-deposit models. Goudarzi (1984) discussed mineral assessment methodology 

and terminology as they apply to these surveys. See 

"Appendixes" for the definition of levels of mineral resource potential and certainty of assessment and for the 

resource/reserve classification.

Area Description

The Lime Canyon Wilderness Study Area (NV-050- 

231) covers approximately 34,680 acres in the desert highlands northeast of Lake Mead (fig. 1). The terrain of the

115°00 114°30' 114°00'

APPROXIMATE BOUNDARY

OF

LIME CANYON

WILDERNESS STUDY AREA

(NV-050-231)

Figure 1. Index map showing location of Lime Canyon Wilderness Study Area, Clark County, Nevada. 

D2 Mineral Resources of Wilderness Study Areas: Southern Nevada
study area is rugged; it rises from about 1,800 ft along the 

west side to sharp ridges above 3,000 ft in the northern part 

and above 4,000 ft in the southern part. The ridges are cut 

by a few steep rocky canyons and are separated by broad 

valleys. The deepest and most spectacular canyon is Lime 

Canyon, which is 1,200 ft deep at its east end. Although 

arid, the study area supports a variety of desert plants 

including native grasses, creosotebush, sagebrush, and 

Joshua trees. The area contains several species of lizards, 

small mammals, and birds including Gambel's quail. Rattlesnakes and desert tortoises inhabit the study area; the 

desert tortoise is listed on the "Federal Register of Threatened and Endangered Species" in the "threatened" category. The study area lies within the Gold Butte Herd Area 

for wild horses and burros. Other mammals include deer, 

bobcats, kit foxes, cottontails, and jack rabbits. The U.S. 

Bureau of Land Management plans to reintroduce bighorn 

sheep in this region. Part of the study area is used for 

grazing cattle.

The study area is accessible from the partly improved Gold Butte road from Mesquite on Interstate Highway 15. This road connects with jeep trails that provide 

access to the east side and parts of the west side of the 

study area.

Previous and Present Investigations

Early interpretations of the geology of the study area 

were made by Longwell (1928), Intermountain Association 

of Petroleum Geologists (1952), Bowyer and others (1958), 

and Longwell and others (1965). The geologic maps 

covering the study area presented in these reports range in 

scale from 1:200,000 to 1:380,365. Morgan (1968) 

mapped the geology of most of the study area at a scale of 

1:31,680. Volborth (1962) studied the Precambrian rocks 

south of the study area. These rocks were dated by Wasserberg and Lanphere (1965). The nonmarine Tertiary 

rocks were studied by Anderson and others (1972), Brenner 

and Glanzman (1979), and Bohannan (1984). The tectonics 

of the Lake Mead region, including the study area, were 

studied by Anderson (1973), Bohannan (1979), and Wernicke and others (1988).

The U.S. Geological Survey carried out field investigations in the study area during 1987. This work included 

geologic reconnaissance and geochemical sampling. 

Samples of the Proterozoic rocks were collected for petrographic analysis. Geochemical data were obtained from 60 

stream-sediment, 119 panned-concentrate (McHugh and 

others, 1989), and 40 rock samples (J.G. Evans, unpub. 

data, 1988).

The U.S. Bureau of Mines conducted field investigations in 1987 that included searches for mines, 

prospects, claims, and mineralized geologic structures 

(Winters, 1988).

APPRAISAL OF IDENTIFIED RESOURCES

By Richard A. Winters 

U.S. Bureau of Mines

Methods

Investigations by the U.S. Bureau of Mines included 

a search of U.S. Bureau of Mines records at the U.S. 

Bureau of Mines Library, Spokane, Wash., and examination of Clark County and U.S. Bureau of Land Management mining, lease, and claim records. Mineral production 

records of the U.S. Bureau of Mines and the State of 

Nevada were also examined. Aerial photographs were used 

in searching for mine workings and their accesses, and in 

determining the extent of the gypsum beds. Field studies 

in 1987 consisted of locating and sampling any mines, 

prospects, claims, and mineralized structures. Gamma-ray 

scintillometer readings were taken throughout the study 

area.

Eighty rock and 59 stream-sediment samples were 

collected. All samples were checked for radioactivity and 

fluorescence. Forty-nine rock samples were analyzed for 

gold by fire assay and atomic-absorption spectrophotometry and for 25 elements by inductively coupled plasmaatomic emission spectroscopy. Of the remaining 31 rock 

samples, 12 gypsum and 4 limestone samples were analyzed for major-element oxides by inductively coupled 

plasma-atomic emission spectroscopy, 12 were analyzed 

for uranium by neutron-activation analysis, 2 were analyzed for zeolites by X-ray diffraction, and 1 was analyzed 

for clay by X-ray diffraction, and 1 was analyzed for alabaster by petrographic evaluation.

Several sampling methods were used. They are (1) 

chip, a continuous series of rock chips taken across the 

measured thickness of a vein, structure, or bed; (2) random 

chip, rock chips taken at random intervals over a given area 

of apparently homogeneous exposure; (3) grab, an assortment of rock fragments; and (4) select, hand-picked chips 

of most altered or mineralized rock available. The streamsediment samples, each consisting of two level 14-in. 

panfuls, were concentrated on a laboratory-sized Wilfley 

table and inspected for microscopic gold and other valuable 

minerals.

Mining History

The wilderness study area is near the Gold Butte 

mining district, most of which is outside the southern 

boundary of the study area. Much of the district's mining 

history as presented here, is taken from Longwell and 

others (1965). Mining activity began in 1873 with Daniel 

Bonelli's discovery of mica deposits a short distance east of 

Gold Butte. Prior to 1900, Bonelli made several shipments

Mineral Resources of the Lime Canyon Wilderness Study Area, Clark County, Nevada D3
of sheet mica totaling an estimated 5 short tons (st). In 

1908, Frank Allsop shipped 2,500 Ib of sheet mica from the 

same area. Later, ultramafic rocks in the vicinity were 

mined for vermiculite.

Metal mining began in 1905 when gold was discovered in veins in the metamorphic and granitic rocks south 

of Gold Butte by Frank Burgess (Vanderburg, 1936). In 

1907, replacement bodies of silver-bearing copper and zinc 

ore were found in Paleozoic limestone north of Gold Butte 

(east of the wilderness study area) by Bonelli, Burgess, 

Syphus, and Gentry. This discovery resulted in enough 

mining activity in 1908 that the camp of Gold Butte was 

established. Small amounts of copper and zinc ore were 

reportedly shipped from this area between 1912 and 1918.

Since 1918, gold-bearing quartz veins in the granitic 

rocks have been the most valuable metallic ores in the 

district see Longwell and others (1965, p. 128) and Couch 

and Carpenter (1943) for metal production figures. The 

data of Longwell and others span the years 1905-62. Total 

production was 2,857 troy oz of gold (less than $100,000 at 

$35 per oz) during this period. One gold claim is presently 

being worked by the Bounsall family.

There are several workings in the wilderness study 

area: three shafts, one adit, and other minor workings in 

carbonate rock and redbeds; seven patented gypsum claims; 

numerous uranium exploration trenches in Tertiary sediments; and current gold claims with minor workings in 

alluvium near Gold Butte. The gold claims may correspond with the operations referred to by Vanderburg (1936, 

p. 63) and Longwell and others (1965, p. 127). Two 

unpatented mineral surveys, at which there are no workings, are located in the study area.

As much as 56 percent of the wilderness study area 

has been under lease or lease application for oil and gas. 

As of March 1987, 37 percent of the study area was still 

under lease application. No drilling has been done in the 

study area, but drilling has been done east of the study area.

Mineral Resources

Seven patented claims cover 861 acres of gypsum 

beds. The beds strike north, dip 35° to 45° E., are 75 to 100 

ft thick, occur in the upper Toroweap Formation, and are 

less resistant to weathering than the underlying limestone 

of the Toroweap Formation and the overlying Kaibab 

Limestone. The gypsum claims were located in 1924, 

recorded in 1928, and patented in 1933 by the McDonald 

Mines Co. All claims are not accurately located. Claim 

papers are on site. Two unpatented claims in the southern 

part of the study area overlap the southern part of one of the 

patented claims. Ten of the eleven rock samples taken 

from the patented claims contain 85 to 99 percent gypsum. 

The other sample contains 59 percent gypsum. Most 

samples have the gypsum content required for mine production (85 to 95 percent gypsum for most gypsum mines; 

Appleyard, 1983). Material containing less than 70 weight 

percent gypsum does not meet the standards for mining and 

industrial use (American Society for Testing and Materials, 

1986). Alabaster, a very fine grained rock gypsum, valued 

by sculptors for its suitability for carving, and occasionally 

found in commercial deposits, crops out in the study area. 

A 75-lb block of white alabaster from the resource area 

with pink banding was judged to have good sculpting 

qualities by a stone cutter. A sample of alabaster, studied 

petrographically, contains 96 percent gypsum, 3 percent 

calcium carbonate, and 1 percent quartz. An estimated 44 

million st subeconomic indicated resource of gypsum is 

present in the study area. This volume was obtained using 

the combined measured strike length of 29,460 ft, 75-ft 

thickness from Morgan (1968, p. 23), an arbitrary downdip 

distance of 300 ft, and a tonnage factor of 13.9 ft3 (cubic 

feet) per st. Parts of one gypsum zone are interlayered with 

carbonate rock. The volume for this 5,000-ft segment was 

calculated using an estimated 40-ft thickness of gypsum. 

Gypsum interbedded with carbonate crops out near one of 

the unpatented mineral surveys but is considered to be 

subeconomic because of its location and small volume it 

lies on a ridge top, has a horizontal extent of no more than 

260 ft, and is less than 100 ft thick. At the present time, 

the gypsum in the study area cannot compete commercially 

with the hundreds of years of reserves of gypsum in the Las 

Vegas area, which are close to markets and transportation.

More than 20 mi2, or about 40 percent of the wilderness study area, is underlain by 12 formations that contain 

limestone or dolomite (Morgan, 1968). The detailed sampling and in-depth study necessary to determine purity and 

volume of carbonate in the study area are beyond the scope 

of this investigation. Extensive mining of limestone in 

Clark County is primarily from the Crystal Pass Member of 

the Sultan Limestone. The limestone is currently being 

mined and abundant reserves of limestone are near markets 

and railroads. The abundance and availability of limestone 

closer to existing markets provide no incentive for further 

study of the limestone in the study area. Three samples of 

carbonate rock taken from the Horse Spring Formation 

(part of unit TMzft, fig. 2) consist of high-calcium limestone suitable for cement (Harben and Bates, 1984, p. 159). 

However, these samples are not representative of limestone 

units throughout the study area.

About 16 mi2 of the western part of the wilderness 

study area is covered by late Tertiary alluvial fans that 

contain millions of cubic yards of sand and gravel. Although the growth of Las Vegas and the needs of the 

nearby military installations and the State of Nevada Department of Transportation have accelerated the demand for 

sand and gravel, these materials are abundant near sites of 

use and transportation. Therefore, the large sand and 

gravel deposits in the study area are likely to be subeconomic into the foreseeable future.

D4 Mineral Resources of Wilderness Study Areas: Southern Nevada
The zeolite mineral clinoptilolite is contained in a 

3.5-ft-thick bed in the Tertiary Horse Spring Formation but 

does not constitute a minable occurrence because of its 

small size.

Permian redbeds (sandstone or sandy shale) that may 

be suitable for flagstone and molding sand occur in the 

study area but are not economic because they are not near 

markets or transportation.

Gold was detected in 8 of 10 tuffaceous and granitic 

rocks with thin quartz veins from the southeastern part of 

the study area. Seven of them contain gold at values from 

0.00032 to 0.012 troy oz per short ton (oz/st) (10 to 1,200 

parts per billion, ppb). One grab sample of quartz from 

alluvium contains 0.201 oz/st (6.3 parts per million, ppm) 

gold. Production of gold from the Gold Butte district came 

from quartz veins in granite south of the study area. Gold 

occurrences are indicated by the data obtained in this study; 

the gold concentrations in the samples are low and no 

continuous mineralized zones or structures were found.

Forty stream-sediment samples were collected from 

drainages throughout the study area. Twelve contain detectable amounts of gold. Eleven samples have gold concentrations ranging from 0.0000097 to 0.00017 troy ounces 

per cubic yard (oz/yd3) ($0.01 to $0.08/yd3 based on a gold 

price of $450/oz). The highest value was 0.00083 oz/yd3 

($0.37/yd3). The source of some of this gold is the Paleozoic and Mesozoic sedimentary rocks of the study area. 

Eighteen alluvial samples were collected from the southeastern corner of the study area near Gold Butte. None of 

these samples contains detectable amounts of gold. Inasmuch as Vanderburg (1936, p. 64) reports gravel in the 

Gold Butte area containing as much as 0.071 oz/yd3 

($32.14/yd3 based on a gold price of $450/oz), the possibility exists that the alluvium samples were taken on ground 

from which the gold had already been extracted by mining. 

This conclusion is consistent with the severe ground disturbance observed during this study. The value of the 

highest gold concentrations in stream-sediment samples 

($0.37/yd3) is much less than the unit production cost of the 

lowest cost domestic placer gold mine known to have 

operated in recent times (to 1984) or $3.95/yd3 at a production rate of 170,000 yd3 per year (Schumacher, 1985). 

Therefore, there are no identified placer gold resources in 

the study area.

Copper and silver were detected in five rock samples 

from five sites in the east-central part of the study area 

(Winters, 1988). A sample from a dump adjacent to a shaft 

contains 0.24 percent copper and 3 ppm silver in gypsiferous sandstone and poorly cemented conglomerate. A 

sample of silty sandstone collected at a dump adjacent to a 

shaft about 300 ft from the first shaft contains 1.8 percent 

copper and 7.5 ppm silver. Three brecciated limestone 

samples from a mineralized shear zone in an adit about 

1,000 ft from the two shafts contain 0.17 to 1.48 percent 

copper and 1 to 2 ppm silver. Two brecciated limestone

samples from the southwestern part of the study area contain high values of copper, lead, silver, and zinc (Winters, 

1988; copper, as much as 151 ppm; lead, as much as 950 

ppm; silver, as much as 1 ppm; and zinc, as much as 1,575 

ppm). On the basis of these data, there are no identified 

resources.

Although the Horse Spring Formation (part of unit 

TMzRt, fig. 2) is a favorable host for uranium accumulation 

in the region, airborne gamma-ray spectrometer data do not 

suggest uranium anomalies in the Horse Spring Formation 

of the study area (Aero Service Division, 1979). Garside 

(1973, p. 21) described one of the uranium prospects in the 

southeastern part of the study area as calcareous green and 

white clays, tuffaceous sediments, and red sandstone that 

contain the uranium-bearing mineral tyuyamunite(?). 

Another claim is in tuffaceous rock that contains very small 

values of gold (10 to 20 ppb). Uranium content in 25 rock 

samples from the southeastern part of the study area ranges 

from 1 to 30 ppm. Only four samples contain more than 16 

ppm uranium. These concentrations are not much greater 

than the 2 ppm crustal abundance for uranium and are 

much less than the approximately 800 ppm uranium needed 

to make mining economically feasible (Finch and others, 

1973). Scintillometer readings near the uranium claims 

were generally only slightly higher than a background of 30 

counts per second (cps) (maximum 115 cps). No uranium 

resources are indicated by these data in the study area.

ASSESSMENT OF MINERAL RESOURCE 

POTENTIAL

By James G. Evans, Gary A. Nowlan, and

Joseph S. Duval

U.S. Geological Survey

Geology

The Lime Canyon Wilderness Study Area is underlain by Proterozoic gneiss and granitic rocks and Paleozoic, Mesozoic, and Tertiary sedimentary rocks, Tertiary 

basalt and fanglomerate, and late Cenozoic alluvium. The 

geology shown in figure 2 is simplified from Morgan 

(1968) and from mapping of the northern part of the study 

area by J.G. Evans.

The oldest rock unit in the study area contains 

medium- to coarse-grained granitic rocks and mediumgrained gneiss, schist, and quartzite. The granitic rocks are 

commonly porphyritic with feldspar phenocrysts as much 

as 2 in. long. Some of these rocks resemble the rapakivitype granite in the Gold Butte area described by Volborth 

(1962). The granitic rocks are hypidiomorphic granular 

and consist mostly of potassium feldspar (40 to 60 percent 

orthoclase, perthite, and microcline), plagioclase (15 to 35 

percent), and quartz (10 to 35 percent) and have composiMineral Resources of the Lime Canyon Wilderness Study Area, Clark County, Nevada D5
114°20'

36° 25'

36° 15'

APPROXIMATE BOUNDARY

OF

LIME CANYON

WILDERNESS STUDY AREA

(NV-050-231)

L/B O,G (area underlain

by TMzft,Tf, QTa)

L/B Ba, Cu, Au, Pb, Ag, Zn 

(area underlain by TMzFt)

QTa

AREA OF AAAP

D6 Mineral Resources of Wilderness Study Areas: Southern Nevada
tions ranging from granite to quartz monzonite. They 

contain as much as 6 percent biotite and 5 percent amphibole, and they also contain minor amounts of magnetite 

and sphene. The metamorphic rocks consist mostly of plagioclase (10 to 65 percent), potassium feldspar (0 to 50 

percent), and quartz (5 to 30 percent for rocks other than 

quartzite). The gneiss and schist also contain as much as

B

Ag 

Au 

Ba 

Cu 

Pb 

Zn 

O,G

EXPLANATION

Area of low mineral resource potential (L)

Levels of certainty of assessment

Data only suggest level of potential

Commodities 

Silver 

Gold 

Barium 

Copper 

Lead 

Zinc 

Oil and gas

Identified resources

Indicated resources of gypsum See text for 

discussion

Inferred resources of carbonate rock (area 

underlain by TMzft ) See text for 

discussion

Inferred resources of sand and gravel (area 

underlain by Tf) See text for discussion

Geologic map units

Alluvium (Quaternary)

Older alluvium (Quaternary and Pliocene)

Fanglomerate (Pliocene)

Basalt (Pliocene)

Sedimentary rocks (Miocene, Mesozoic, and

Paleozoic) 

Granitoid and gneiss (Middle and Early

Proterozoic)

Contact

Fault Dotted where concealed

Thrust fault Sawteeth on upper plate

 ^ Figure 2. Mineral resource potential and generalized 

geology of Lime Canyon Wilderness Study Area, Clark 

County, Nevada.

1

0 °»c 

« 0 C * -

Qa 

QTa 

Tf 

Tb

YX

20 percent pyroxene, as much as 10 percent biotite, as 

much as 28 percent amphibole, and as much as 2 percent 

opaque minerals; they also contain minor amounts of 

sphene and zircon. The feldspars in the granitoids, gneiss, 

and schist are moderately altered to sericite, contain some 

muscovite, and are slightly saussuritized. The biotite is 

slightly altered to chlorite, mafic minerals are slightly to 

very altered to hematite, and some rocks show minor carbonate replacement. Wasserburg and Lanphere (1965) 

reported rubidium-strontium ages for the metamorphic 

rocks near Gold Butte, just south of the study area, at 1,700 

million years before present (Ma) (Early Proterozoic). 

They also dated the granitic rocks near Gold Butte at 1,060 

Ma (Middle Proterozoic). The age of the granitic and 

metamorphic rocks is considered to be Early and Middle 

Proterozoic.

The Paleozoic, Mesozoic, and Miocene sedimentary 

rocks that overlie the Proterozoic rocks are combined into 

one unit in this report. The stratigraphic nomenclature is 

from Morgan (1968). This unit includes the following 

Paleozoic formations that have a total stratigraphic thickness of 6,800 ft: Prospect Mountain Quartzite, Pioche 

Shale, Lyndon Limestone, Chisholm Shale, Peasley Limestone, and an unnamed dolomite, all of Cambrian age; 

unnamed dolomite and sandstone of Cambrian or Ordovician age; the Devonian Muddy Peak Limestone; the Mississippian Monte Cristo Limestone; the Pennsylvanian 

Callville Limestone; and the Pakoon Limestone, Queantoweap Sandstone, Hermit Formation (sandstone), Coconino Sandstone, Toroweap Formation (gypsum, sandstone, limestone), and Kaibab Limestone, all of Permian 

age. The unit also includes the following Mesozoic formations that have a combined stratigraphic thickness of 3,700 

ft: the Moenkopi Formation (gypsum, gypsiferous shale, 

limestone) and Chinle Formation (sandstone) of Triassic 

age, and the Aztec Sandstone of Triassic(?) to Jurassic age. 

The unit includes die following Miocene formations that 

may have a combined stratigraphic thickness of more than 

2,500 ft: an unnamed fanglomerate, the Horse Spring 

Formation (limestone, andesite, tuff, sandstone, magnesite, 

shale, gypsum), and the Muddy Creek Formation (gypsiferous sandstone and siltstone).

Unconsolidated fanglomerate that crops out along 

the west side of the study area is interbedded with basalt 

along the southeast boundary near Gold Butte. The rocks 

are younger than the Muddy Creek Formation and may be 

Pliocene in age.

Older alluvium, probably ranging in age from Pliocene to Holocene is present in the northeastern and southeastern parts of the study area. Holocene alluvium occupies the bottoms of two canyons in the southern part of the 

study area.

The study area is cut by numerous faults, only a few 

of which, possibly the most significant ones, are shown in 

figure 2. The Lime Ridge and Gold Butte faults are part

Mineral Resources of the Lime Canyon Wilderness Study Area, Clark County, Nevada D7
of the Lake Mead fault system (Bohannan, 1979, 1984); 

both show about 6 mi of left-lateral separation that occurred between 17 and 13 Ma. Cross sections by Morgan 

(1968) of the Virgin Mountains (fig. 1) show a low-angle 

normal fault beneath much of the study area. Part of this 

fault is exposed at the east end of Lime Canyon. This fault 

affected the unnamed fanglomerate and Horse Spring Formation and, therefore, must have been active during the 

Miocene after about 12 Ma. Block faulting from 12 to 6 

Ma tilted strata (Bohannan, 1984). As much as 40 mi of 

left-lateral slip may have taken place on the Lake Mead 

fault system (Anderson, 1973; Bohannan, 1979). The 

study area is near the eastern end of a zone of late Tertiary 

to Holocene crustal deformation that extends from the 

southern Sierra Nevada to the Colorado Plateau. This zone 

has undergone as much as 150 mi west-northwest extension (Wernicke and others, 1988).

Geochemical Studies

A reconnaissance geochemical survey was conducted in the Lime Canyon Wilderness Study Area. Minus-80-mesh stream sediments, panned concentrates derived from stream sediments, and rocks were collected 

during this study. Samples of stream sediment and panned 

concentrates were collected at 60 sites. Forty altered rock 

samples were collected, mostly from the Proterozoic rocks 

in the southern part of the study area, to determine the suite 

of elements associated with any mineralization that may 

have occurred in the area. Twelve unaltered samples of 

Proterozoic rock were taken for petrographic analysis.

Stream-sediment samples were collected from alluvium in active stream channels. Stream sediments represent a composite of the rock and soil exposed upstream 

from the sample site. The panned-concentrate samples 

represent a concentration of minerals that may be ore forming or ore related and permit determination of some elements that are not easily detected in bulk stream sediments. 

Two panned-concentrate samples were collected at each 

site. One sample was further concentrated by a series of 

steps using bromoform and magnetic separations to produce a "nonmagnetic heavy-mineral-concentrate sample." 

The other sample was analyzed for gold without further 

treatment and is termed a "raw panned-concentrate 

sample."

The stream sediments were analyzed for 35 elements, and the rock samples were analyzed for 31 elements 

using a semiquantitative direct-current arc emission spectrographic method (Grimes and Marranzino, 1968). Nonmagnetic heavy-mineral concentrates were analyzed for 37 

elements by the same method. In addition, samples were 

analyzed for certain elements by more sensitive methods. 

Stream-sediment samples were also analyzed for gold by 

graphite furnace atomic absorption (Meier, 1980; O'Leary

and Meier, 1986), for uranium by ultraviolet fluorimetry 

(Centanni and others, 1956; O'Leary and Meier, 1986), and 

for antimony, arsenic, bismuth, cadmium, and zinc by 

inductively coupled plasma-atomic emission spectroscopy 

(Crock and others, 1987). The raw panned-concentrate 

sample was analyzed for gold by flame atomic absorption 

(Thompson and others, 1968; O'Leary and Meier, 1986). 

Rock samples were also analyzed for gold, mercury, and 

uranium by methods mentioned above (gold, Thompson 

and others, 1968; O'Leary and Meier, 1986; mercury, 

Crock and others 1987; uranium, Centanni and others, 

1956; O'Leary and Meier, 1986). These analyses were 

used to identify drainages containing anomalous concentrations of elements indicative of mineralization. Anomalous 

concentrations in the stream-sediment, panned-concentrate, 

and rock samples were determined for each element by 

statistical examination of the data, by comparison of the 

data from the study area with data from nearby wilderness 

study areas (El Dorado, Ireteba Peaks, and Million Hills, 

McHugh and others, 1989 a, b), and by comparison to 

element concentrations in rocks listed by Rose and others 

(1979).

The study area contains anomalous concentrations of 

several elements, of which arsenic, barium, copper, gold, 

lead, molybdenum, silver, thorium, tin, tungsten, and zinc 

possibly resulted from mineralization. Areas underlain by 

rocks containing anomalous concentrations of some of 

these elements are shown in figure 2.

Samples collected in most drainages underlain by 

Paleozoic, Mesozoic, and Miocene sedimentary rocks are 

rich in barium; the values detected in heavy-mineral-concentrate samples are greater than 10,000 ppm and suggest 

the possibility that bedded barite deposits crop out in the 

study area (fig. 2).

Samples from three small areas adjacent to the areas 

having samples anomalous in barium also contain anomalous amounts of gold (0.33 to 0.65 ppm in raw pannedconcentrate samples). These areas are near sites at which 

the U.S. Bureau of Mines took stream-sediment samples 

that contain minute amounts of gold. Rock samples containing barium and gold collected on the east side of the 

study area also contain small amounts of copper, lead, silver, and zinc. The gold in this area may be related to the 

mineralization event during which these metals were concentrated. The two areas from which samples containing 

barium and gold were collected on the north and west sides 

of the study area are in largely unaltered sedimentary rock. 

This gold may be syngenetic or could have been deposited 

in or near faults by hydrothermal solutions.

Silver (0.5 to 1.5 ppm) occurs in samples of altered 

Proterozoic rocks and silicified carbonate rocks in the 

south-central part of the study area, where it is associated 

with lead (100 to 1,000 ppm) and zinc (200 to 1,500 ppm). 

A raw panned-concentrate sample from a small drainage at 

the south end of the study area contains an anomalous value

06 Mineral Resources of Wilderness Study Areas: Southern Nevada
of gold (0.1 ppm). The drainage contains the rock types 

that nearby have anomalous concentrations of silver, although silver was not detected in samples collected from 

that drainage.

Very small amounts of gold (0.02 to 0.04 ppm) were 

detected in panned concentrates from sediments in canyons 

that cut through the Proterozoic and carbonate rocks and 

Tertiary fanglomerate in the southwestern part of the study 

area.

High concentrations of lead (as much as 2,000 ppm) 

are found in heavy-mineral-concentrate samples from 

drainages in a band across the central part of the study area. 

Some of these samples also have high concentrations of 

barium (greater than 10,000 ppm) and zinc (as much as 

3,000 ppm), and some have no anomalous concentrations 

of lead, barium, zinc, or any other elements.

Fairly high values of tungsten (100 to 300 ppm) and 

barium are contained in heavy-mineral-concentrate samples 

from the east edge of the study area. Examination of 

nonmagnetic heavy-mineral-concentrate samples from the 

southeastern part of the study area under ultraviolet light 

shows the tungsten-bearing minerals scheelite and powellite (molybdenum-bearing scheelite) in approximately 

equal quantities. Scheelite and powellite occur in granitic 

dikes that cut Proterozoic rocks 13 mi southeast of the 

study area (Longwell and others, 1965). These minerals 

may have been deposited by hydrothermal fluids moving 

upward along faults from sources deep in Proterozoic rock.

Thorium occurs in fairly high concentrations (700 to 

5,000 ppm) in heavy-mineral-concentrate samples from the 

southeastern corner of the study area. The thorium-bearing 

minerals may have come from Proterozoic rocks in the 

study area and/or from reworked alluvium derived from 

Proterozoic rocks south of the study area.

Geophysical Studies

Aerial gamma-ray spectroscopy is a technique that 

provides estimates of the near-surface (to a maximum depth 

of about 20 in.) concentrations of percent potassium (K), 

ppm equivalent uranium (eU), and ppm equivalent thorium 

(eTh). Because the uranium and thorium measurements 

include radioactive daughter nuclei that are chemically 

distinct from the parent nuclei, the uranium and thorium 

data are described as equivalent concentrations. These data 

(K, eU, eTh) provide a partial geochemical representation 

of the near-surface materials. For a typical aerial survey, 

each measurement reflects average concentrations for a 

surface area of about 645,000 square feet to an average 

depth of about 12 in.

From 1975 to 1983, the U.S. Department of Energy 

contracted for aerial gamma-ray surveys that covered almost all the conterminous United States and much of 

Alaska. The flightline spacings of these surveys vary from

1 mi (rare) to 10 mi and are, in general, only suitable for 

producing regional-scale maps.

As part of a state mapping project, the data for 

Nevada and New Mexico were compiled and processed to 

produce a series of l:l,000,000-scale maps. These maps 

include composite-color maps by Duval (1983). These 

maps were examined to estimate the K, eU, and eTh concentrations for each of several wilderness study areas, 

including the Lime Canyon Wilderness Study Area, and the 

occurrence or absence of anomalous radioelement concentrations were noted. The definition of an anomaly requires 

that the element concentration as well as its ratios to the 

other two elements all be high values in the context of the 

map.

The Lime Canyon Wilderness Study Area has overall low radioactivity with values of 0-1.2 percent K, 1-2 

ppm eU, and 0-6 ppm eTh. No radioactivity anomalies 

exist within the boundaries of the study area or in the 

immediate vicinity. The uranium composite-color map 

suggests slight enrichment of uranium relative to potassium 

and thorium, but such enrichment is characteristic of the 

carbonate rocks in the southern part of Nevada, and the 

absolute concentrations of uranium are low.

Mineral and Energy Resource Potential

Geological and geochemical data indicate that the 

pan of the study area underlain by Paleozoic, Mesozoic, 

and Tertiary rocks has low resource potential for barium, 

copper, gold, lead, silver, and zinc with a B certainty level 

(fig. 2). Anomalous concentrations of these six elements 

occur in rock, stream-sediment, and panned-concentrate 

samples. These elements, along with molybdenum, tin, and 

tungsten, may indicate local hydrothermal alteration. The 

close association of most high barium concentrations in 

panned-concentrate samples with apparently unaltered sedimentary rocks suggests that bedded barite deposits may be 

present. The presence of anomalous concentrations of 

copper, lead, silver, and zinc in the three sample types and 

the occurrences of these elements studied by the U.S. 

Bureau of Mines suggest that carbonate replacement deposits similar to the ones along Tramp Ridge, 2 mi east of the 

study area (Longwell and others, 1965), may be present. 

The low level of potential is suggested by the lack of 

deposits found in the well-exposed rocks of the study area 

that have been mapped in detail (Morgan, 1968). The 

certainty level B is assigned because the data only suggest 

the level of resource potential.

Thorium occurs in fairly high concentrations in 

heavy-mineral-concentrate samples from the southeastern 

part of the study area. The thorium is probably from 

Proterozoic rocks in and/or south of the study area and 

these concentrations do not suggest that resources of thorium are present in the study area.

Mineral Resources of the Lime Canyon Wilderness Study Area, Clark County, Nevada D9
The oil and gas potential of the study area is low 

based on nearby oil and gas shows and recent exploratory 

drilling just north of the study area (Sandberg, 1983). 

Since 1983 much of the study area has come under lease or 

application for oil and gas and drilling has been done 2 mi 

east of the study area. The resource potential for oil and 

gas is low, certainty level B, for the part of the study area 

underlain by Paleozoic, Mesozoic, and Miocene sedimentary rocks. Some of the fanglomerate and older alluvium 

in the study area is underlain by these sedimentary rocks 

and, therefore, has been included in the part of the study 

area that has low potential for oil and gas.

No geothermal resources were found in or adjacent 

to the study area (Muffler, 1979). Although the study area 

contains Tertiary basalt at its south end and is in a region 

that probably underwent greater than normal heat flow 

during the Miocene to early Pliocene, the entire region has 

most likely cooled to near ambient temperatures since the 

early Pliocene. Therefore, no potential exists for geothermal resources, certainty level D.

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Aero Service Division, 1979, Airborne gamma-ray spectrometer 

and magnetometer survey, Las Vegas quadrangle, GJBX-59 

Final Report, v. 1 and 2: Western Geophysical Company of 

America, Subcontract no. 77-062-L, project no. 44-77-4118, 

Grand Junction, Colorado, v. 1, 70 p. with appendices A-J, v. 

2, 121 p.

American Society for Testing and Materials, 1986, Gypsum and 

related building materials and systems: Construction, Section 4, American Society for Testing and Materials, Philadelphia, Perm., p. 3-8.

Anderson, R.E., 1973, Large-magnitude Late Tertiary strike-slip 

faulting north of Lake Mead, Nevada: U.S. Geological 

Survey Professional Paper 794, 18 p.

Anderson, R.E., Longwell, C.R., Armstrong, R.L., and Marvin, 

R.F., 1972, Significant of K-Ar ages of Tertiary rocks from 

the Lake Mead region, Nevada-Arizona: Geological Society 

of America Bulletin, v. 83, no. 2, p. 273-288.

Appleyard, F.C., 1983, Gypsum and anhydrite, in Lefond, S.J., 

ed., Industrial Minerals and Rocks, 5th ed., v. 2: American 

Institute of Mining, Metallurgical, and Petroleum Engineers, 

Inc., p. 775-792.

Beikman, H.M., Hinkle, M.E., Frieders, Twila, Marcus, S.M., and 

Edward, J.R., 1983, Mineral surveys by the Geological Survey and the Bureau of Mines of Bureau of Land Management 

Wilderness Study Areas: U.S. Geological Survey Circular 

901, 28 p.

Bohannan, R.G., 1979, Strike-slip faults of the Lake Mead region 

of southern Nevada, in Armentrout, J.M., Cole, M.R., and 

TerBest, Harry, Jr., Cenozoic paleogeography of the western 

United States: Society of Economic Paleontologists and 

Mineralogists, Pacific Coast Paleogeography Symposium 3, 

p. 129-139.

 1984, Nonmarine sedimentary rocks of Tertiary age 

in the Lake Mead region, southeastern Nevada and northwestern Arizona: U.S. Geological Survey Professional 

Paper 1259, 72 p.

Bowyer, Ben, Pampeyan, E.H., and Longwell, C.R., 1958, Geologic map of Clark County, Nevada: U.S. Geological Survey 

Miscellaneous Field Investigations Map MF-138, scale 

1:200,000.

Brenner, E.F. and Glanzman, R.K., 1979, Tertiary sediments of 

the Lake Mead area, Nevada, in Newman, G.W., and Goode, 

H.D., eds., Basin and Range Symposium and Great Basin 

Field Conference: Rocky Mountain Association of Geologists, Denver, p. 313-323.

Centanni, F.A., Ross, A.M., and DeSesa, M.A., 1956, Fluorometric determination of uranium: Analytical Chemistry, v. 28, p. 

1651.

Couch, B.F. and Carpenter, J.A., 1943, Nevada's metal and 

mineral production (1859-1940, inclusive): Nevada Bureau 

of Mines and Geology Bulletin 38, no. 4, 159 p.

Crock, J.G., Briggs, P.H., Jackson, L.L., and Lichte, F.E., 1987, 

Analytical methods for the analysis of stream sediments and 

rocks from the wilderness study areas: U.S. Geological 

Survey Open-File Report 87-84, 35 p.

Duval, J.S., 1983, Composite color images of aerial gamma-ray 

spectrometric data: Geophysics, v. 48, no. 6, p. 722-735.

Finch, W.I., Butler, A.P., Jr., Amstrong, F.C., and Weissenbom, 

A.E., 1973, Uranium, in United States Mineral Resources, 

Brobst, D.A., and Pratt, W.P., eds.: U.S. Geological Survey 

Professional Paper 820, p. 456-468.

Garside, L.J., 1973, Radioactive mineral occurrences in Nevada: 

Nevada Bureau of Mines and Geology Bulletin 81, 121 p.

Goudarzi, 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, DJ. and Marranzino, A.P., 1968, Direct-current arc and 

alternating-current spark emission spectrographic field methods for the semiquantative analysis of geologic materials: 

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

Harben, P.W. and Bates, R.L., 1984, Geology of the nonmetallics: 

New York, Metal Bulletin, Inc., 392 p.

Intermountain Association of Petroleum Geologists, 1952, Guidebook to the geology of Utah; No. 7, Cedar City, Utah to Las 

Vegas, Nevada: 165 p., 1 pi., scale 1:380,365

Longwell, C.R., 1928, Geology of the Muddy Mountains, Nevada: 

U.S. Geological Survey Bulletin 798, 152 p.

Longwell, C.R., Pampeyan, E.H., Bowyer, Ben, and Roberts, R.J., 

1965, Geology and mineral deposits of Clark County, Nevada: Nevada Bureau of Mines Bulletin 62, 218 p.

McHugh, J.B., Bullock, J.H., Jr., Roemer, T.A., Briggs, P.H., and 

Nowlan, G.A., 1989a, Analytical results and sample locality 

map for stream-sediment and panned-concentrate samples 

from the Lime Canyon and Million Hills Wilderness Study 

Areas, Clark County, Nevada: U.S. Geological Survey 

Open-File Report 89-025, 21 p.

McHugh, J.B., Bullock, J.H., Jr., Roemer, T.A., and Nowlan, 

G.A., 1989b, Analytical results and sample locality map for 

stream-sediment and panned-concentrate samples from the El 

Dorado and Ireteba Peaks Wilderness Study Areas, Clark 

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

89-022, 19 p.

McKelvey, V.E., 1972, Mineral resource estimates and public 

policy: American Scientist, v. 60, p. 32-40.

D10 Mineral Resources of Wilderness Study Areas: Southern Nevada
Meier, A.L., 1980, Flameless atomic-absorption determination of 

gold in geological materials: Journal of Geochemical Exploration, v. 13, p. 77-85.

Morgan, J.R., 1968, Structure and stratigraphy of the northern part 

of the South Virgin Mountains, Clark County, Nevada: 

Unpub. thesis, Albuquerque, N. Mex., University of New 

Mexico 103 p.

Muffler, L.J.P., 1979, Assessment of geothermal resources of the 

United States 1978: U.S. Geological Survey Circular 790, 

163 p.

O'Leary, R.M., and Meier, A.L., 1986, Analytical methods used 

in geochemical exploration, 1984: U.S. Geological Survey 

Circular 948, 48 p.

Rose, A.W., Hawkes, H.E., and Webb, J.S., 1979, Geochemistry 

in mineral exploration (2d ed.): London, Academy Press, 

657 p.

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

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

Schumacher, O.L., 1985, Placer gold production and cost history 

of an Alaska placer gold mine, in Schumacher, O.L., ed., 

Mining Cost Service: Spokane, Wash., Western Mine Engineering, p. B1-B5.

Thompson, C.E., Nakagawa, H.M., and Van Sickle, G.H., 1968, 

Rapid analyses for gold in geologic materials, in Geological 

Survey Research 1968: U.S. Geological Survey Professional 

Paper 600, p. B130-B132.

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.

Vanderburg, W.O., 1936, Placer mining in Nevada: Nevada 

Bureau of Mines and Geology Bulletin 27, 180 p.

Volborth, A., 1962, Rapakivi-type granites in the Precambrian 

complex of Gold Butte, Clark County, Nevada: Geological 

Society of America Bulletin, v. 73, no. 7, p. 813-831.

Wasserburg, G.J., and Lanphere, M.A., 1965, Age determinations 

in the Precambrian of Arizona and Nevada: Geological 

Society of America Bulletin, v. 76, no. 7, p. 735-758.

Wernicke, Brian, Axen, G.J., and Snow, J.K., 1988, Basin and 

range extensional tectonics at the latitude of Las Vegas: 

Geological Society of America Bulletin, v. 100, no. 11, p. 

1738-1757.

Winters, R.A., 1988, Mineral resources of the Lime Canyon 

Wilderness Study Area, Clark County, Nevada: U.S. Bureau 

of Mines Open-File Report MLA 40-88, 42 p.

Mineral Resources of the Lime Canyon Wilderness Study Area, Clark County, Nevada D11

APPENDIXES
DEFINITION OF LEVELS OF MINERAL RESOURCE POTENTIAL 

AND CERTAINTY OF ASSESSMENT

LEVELS OF RESOURCE POTENTIAL

H 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.

M 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 for resource accumulation, and (or) where an application of mineral-deposit models 

indicates favorable ground for the specified type(s) of deposits.

L 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 little or no indication of having 

been mineralized.

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

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

moderate, or high level of resource potential.

LEVELS OF CERTAINTY

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

B Available information only 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.

UJ 

UJ

A

U/A

UNKNOWN POTENTIAL

B

H/B

HIGH POTENTIAL

M/B

MODERATE POTENTIAL

L/B

LOW POTENTIAL

C

H/C

HIGH POTENTIAL

M/C

MODERATE POTENTIAL

L/C

LOW POTENTIAL

D

H/D

HIGH POTENTIAL

M/D

MODERATE POTENTIAL

L/D

LOW POTENTIAL

N/D

NO POTENTIAL

LEVEL OF CERTAINTYAbstracted 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.

D14 Mineral Resources of Wilderness Study Areas: Southern Nevada
RESOURCE/RESERVE CLASSIFICATION

ECONOMIC

MARGINALLY 

ECONOMIC

SUBECONOMIC

IDENTIFIED RESOURCES

Demonstrated

Measured

Rese

Indicated

irves

Marginal 

Reserves

Demonstrated 

Subeconomic 

Resources

Inferred

Inferred 

Reserves

Inferred 

Marginal 

Reserves

Inferred 

Subeconomic 

Resources

UNDISCOVERED RESOURCES

Probability Range

Hypothetical Speculative

Major elements of mineral resource classification, excluding reserve base and inferred reserve base. Modified from McKelvey, V.E., 1972, Mineral 

resource estimates and public policy: American Scientist, v. 60, p. 32-40; and 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, p. 5.

Mineral Resources of the Lime Canyon Wilderness Study Area, Clark County, Nevada D15
GEOLOGIC TIME CHART

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

EON

Phanerozoic

ProCerozoic

Archean

pre-Archean2

ERA

Cenozoic

Mesozoic

Paleozoic

Late Proterozoic

Middle Proterozoic

Early Proterozoic

Late Archean

Middle Archean

Early Archean

PERIOD

Quaternary

Neogene

Subperiod

Tertiary ,

Paleogene 

Subperiod

Cretaceous

Jurassic

Triassic

Permian

Pennsylvanian 

Carboniferous

Periods

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 

MILLION YEARS (Ma)

 0.010

 1.7

 5

1 A

Tfl

 55

 66

96

1 no

 205

1Af\

 290 

 -330

 360 

 410

T.JI-J

 500

 '-570

.7\As

 1600

 2500

*JV/W

»J*tWV/

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

'Informal time term without specific rank.

D16 Mineral Resources of Wilderness Study Areas: Southern Nevada


SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS

Periodicals

Earthquakes & Volcanoes (issued bimonthly). 

Preliminary Determination of Epicenters (issued monthly).

Technical Books and Reports

Professional Papers are mainly comprehensive scientific reports of 

wide and lasting interest and importance to professional scientists and engineers. Included are reports on the results of resource studies and of 

topographic, hydrologic, and geologic investigations. They also include 

collections of related papers addressing different aspects of a single scientific topic.

Bulletins contain significant data and interpretations that are of lasting scientific interest but are generally more limited in scope or 

geographic coverage than Professional Papers. They include the results 

of resource studies and of geologic and topographic investigations; as well 

as collections of short papers related to a specific topic.

Water-Supply Papers are comprehensive reports that present significant interpretive results of hydrologic investigations of wide interest 

to professional geologists, hydrologists, and engineers. The series covers 

investigations in all phases of hydrology, including hydrogeology, 

availability of water, quality of water, and use of water.

Circulars present administrative information or important scientific 

information of wide popular interest in a format designed for distribution 

at no cost to the public. Information is usually of short-term interest.

Water-Resources Investigations Reports are papers of an interpretive nature made available to the public outside the formal USGS publications series. Copies are reproduced on request unlike formal USGS 

publications, and they are also available for public inspection at 

depositories indicated in USGS catalogs.

Open-File Reports include unpublished manuscript reports, maps, 

and other material that are made available for public consultation at 

depositories. They are a nonpermanent form of publication that may be 

cited in other publications as sources of information.

Maps

Geologic Quadrangle Maps are multicolor geologic maps on 

topographic bases in 7 1/2- or 15-minute quadrangle formats (scales mainly 1:24,000 or 1:62,500) showing bedrock, surficial, or engineering geology. Maps generally include brief texts; some maps include structure 

and columnar sections only.

Geophysical Investigations Maps are on topographic or planimetric 

bases at various scales; they show results of surveys using geophysical 

techniques, such as gravity, magnetic, seismic, or radioactivity, which 

reflect subsurface structures that are of economic or geologic significance. 

Many maps include correlations with the geology.

Miscellaneous Investigations Series Maps are on planimetric or 

topographic bases of regular and irregular areas at various scales; they 

present a wide variety of format and subject matter. The series also includes 71/2-minute quadrangle photogeologic maps on planimetric bases 

which show geology as interpreted from aerial photographs. Series also 

includes maps of Mars and the Moon.

Coal Investigations Maps are geologic maps on topographic or 

planimetric bases at various scales showing bedrock or surficial geology, stratigraphy, and structural relations in certain coal-resource areas.

Oil and Gas Investigations Charts show stratigraphic information 

for certain oil and gas fields and other areas having petroleum potential.

Miscellaneous Field Studies Maps are multicolor or black-andwhite maps on topographic or planimetric bases on quadrangle or irregular areas at various scales. Pre-1971 maps show bedrock geology 

in relation to specific mining or mineral-deposit problems; post-1971 

maps are primarily black-and-white maps on various subjects such as 

environmental studies or wilderness mineral investigations.

Hydrologic Investigations Atlases are multicolored or black-andwhite maps on topographic or planimetric bases presenting a wide range 

of geohydrologic data of both regular and irregular areas; principal scale 

is 1:24,000 and regional studies are at 1:250,000 scale or smaller.

Catalogs

Permanent catalogs, as well as some others, giving comprehensive listings of U.S. Geological Survey publications are available under 

the conditions indicated below from the U.S. Geological Survey, Books 

and Open-File Reports Section, Federal Center, Box 25425, Denver, 

CO 80225. (See latest Price and Availability List)

"Publications of the Geological Survey, 1879-1961" may be purchased by mail and over the counter in paperback book form and as a 

set of microfiche.

"Publications of the Geological Survey, 1962-1970" may be purchased by mail and over the counter in paperback book form and as a 

set of microfiche.

"Publications of the U.S. Geological Survey, 1971-1981" may be 

purchased by mail and over the counter in paperback book form (two 

volumes, publications listing and index) and as a set of microfiche.

Supplements for 1982,1983,1984,1985,1986, and for subsequent 

years since the last permanent catalog may be purchased by mail and 

over the counter in paperback book form.

State catalogs, "List of U.S. Geological Survey Geologic and 

Water-Supply Reports andMaps For (State)," may be purchased by mail 

and over the counter in paperback booklet form only.

"Price and Availability List of U.S. Geological Survey Publications," issued annually, is available free of charge in paperback booklet form only.

Selected copies of a monthly catalog "New Publications of the U.S. 

Geological Survey" available free of charge by mail or may be obtained 

over the counter in paperback booklet form only. Those wishing a free 

subscription to the monthly catalog "New Publications of the U.S. 

Geological Survey" should write to the U.S. Geological Survey, 582 

National Center, Reston, VA 22092.

Note. Prices of Government publications listed in older catalogs, 

announcements, and publications may be incorrect. Therefore, the 

prices charged may differ from the prices in catalogs, announcements, 

and publications.
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