U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2016–5089–B

Version 1.1, October 28, 2016

Prepared in cooperation with the Bureau of Land Management

Geology and Mineral Resources of the Sheldon-Hart Mountain 

National Wildlife Refuge Complex (Oregon and Nevada), the 

Southeastern Oregon and North-Central Nevada, and the 

Southern Idaho and Northern Nevada (and Utah) Sagebrush 

Focal Areas

Chapter B of

Mineral Resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, 

Oregon, Utah, and Wyoming
COVER. Photograph of remains of cyanide mill, National District, Nevada (U.S. Geological Survey photograph by Peter G. Vikre).
Geology and Mineral Resources of the SheldonHart Mountain National Wildlife Refuge 

Complex (Oregon and Nevada), the Southeastern 

Oregon and North-Central Nevada, and the 

Southern Idaho and Northern Nevada (and Utah) 

Sagebrush Focal Areas

By Peter G. Vikre, Mary Ellen Benson, Donald I. Bleiwas, Joseph P. Colgan, Pamela M. 

Cossette, Jacob DeAngelo, Connie L. Dicken, Ronald M. Drake II, Edward A. du Bray, 

Gregory L. Fernette, Jonathan M.G. Glen, Jon E. Haacke, Susan M. Hall, Albert H. Hofstra, 

David A. John, Stephen Ludington, Mark J. Mihalasky, James J. Rytuba, Brian N. Shaffer, 

Lisa L. Stillings, John C. Wallis, Colin F. Williams, Douglas B. Yager, and Lukas Zürcher

Chapter B of

Mineral Resources of the Sagebrush Focal Areas of Idaho, Montana, 

Nevada, Oregon, Utah, and Wyoming

Edited by Warren C. Day, Thomas P. Frost , Jane M. Hammarstrom, and Michael L. Zientek

Prepared in cooperation with the Bureau of Land Management

Scientific Investigations Report 2016–5089–B

Version 1.1, October 28, 2016

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Director

U.S. Geological Survey, Reston, Virginia

First release: 2016

Revised: October 27, 2016 (ver. 1.1)

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

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For an overview of USGS information products, including maps, imagery, and publications, 

visit http://store.usgs.gov.

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U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Vikre, P.G., Benson, M.E., Bleiwas, D.I., Colgan, J.P., Cossette, P.M., DeAngelo, J., Dicken, C.L., Drake, R.M., II, 

du Bray, E.A., Fernette, G.L., Glen, J.M.G., Haacke, J.E., Hall, S.M., Hofstra, A.H., John, D.A., Ludington, S., 

Mihalasky, M.J., Rytuba, J.J., Shaffer, B.N., Stillings, L.L., Wallis, J.C., Williams, C.F., Yager, D.B., and Zürcher, L., 

2016, Geology and mineral resources of the Sheldon-Hart Mountain National Wildlife Refuge Complex (Oregon and 

Nevada), the Southeastern Oregon and North-Central Nevada, and the Southern Idaho and Northern Nevada (and 

Utah) Sagebrush Focal Areas (ver. 1.1, October 28, 2016): U.S. Geological Survey Scientific Investigations Report 

2016–5089–B, 224 p., http://dx.doi.org/10.3133/sir20165089B.

ISSN 2328-0328 (online)
iii

Acknowledgments

Numerous persons assisted in preparation, accuracy, and completeness of this report. Ian 

Madin and Bob Houston, Oregon Department of Geology and Mineral Industries, and Ken 

Krahulec, Utah Geological Survey, participated in assessment tract delineation and rating 

and were ready sources of information on mineral resources in their respective states. 

Maps created by the Nevada Bureau of Mines and Geology (NBMG) that show areas of 

high mineral potential in northern Nevada (http://minerals.nv.gov/home/features/Mineral,_

Geothermal_and_Oil___Gas_Potential_Maps_of_Sagebrush_Focal_Areas_-_6/24/2015/), 

and discussions with James Faulds and John Muntean, NBMG, helped to guide the scope 

and content of this report. Location and status of Plans of Operation in the Humboldt-Toiyabe 

National Forest of Nevada were provided by Susan Elliott, U.S. Forest Service. Carma San 

Juan provided geographic information system (GIS), databases services, oversight, and figure 

construction. Thomas P. Frost, David A. Ponce, Barnaby W. Rockwell, and Steven M. Smith 

provided management perspective and geophysical and geochemical data and discussion 

that helped guide assessment tract delineation and rating. Michael L. Zientek provided report 

templates. Advisory Oversight Committee members Donald I. Bleiwas, Stephen E. Box, Jane 

M. Hammarstrom, Gilpin R. Robinson, and Michael L. Zientek provided advice on buffering 

assessment tract boundaries and on delineation and rating of cospatial tracts for different 

deposit types. Reviews by Charles Thorman, Ryan Taylor, and Kathryn Watts evaluated 

validity of assessment tracts and improved presentation content and style.
iv

Author Responsibilities

Peter G. Vikre—Introductory text, conjunctive text, summarizing text, and editing for all sections; contributions to exploration and mining activity, tract descriptions, and locatable mineral 

commodities not assessed

Mary Ellen Benson—Tract delineation, rating, and description for phosphate occurrences and 

diatomite deposits; figure construction

Donald I. Bleiwas—Market analyses of assessed locatable mineral commodities

Joseph P. Colgan—Geology; figure construction

Pamela M. Cossette—GIS; figure construction

Jacob DeAngelo—Geothermal occurrences; figure construction

Connie L. Dicken—GIS; land use statistics

Ronald M. Drake II—Oil and gas; figure construction

Edward A. du Bray—Geology; locatable mineral commodities not assessed

Gregory L. Fernette—Exploration and mining activity

Jonathan M.G. Glen—Geothermal occurrences; figure construction

Jon E. Haacke—Coal occurrences; figure construction

Susan M. Hall—Tract delineation, rating, and description for hydroallogenic uranium deposits; 

locatable mineral commodities not assessed

Albert H. Hofstra—Tract delineation, rating, and description for orogenic gold, epithermal 

gold and silver, volcanogenic massive sulfide copper, Carlin-type gold, black shale vanadium, 

sedimentary exhalative zinc-lead-silver-gold, Mississippi Valley-type lead and zinc, and bedded 

barite deposits

David A. John—Tract delineation, rating, and description for epithermal gold, silver, and 

mercury deposits

Stephen Ludington—GIS; tract delineation, rating, and description for epithermal gold and 

silver, and intrusion-related deposits 

Mark J. Mihalasky—GIS; tract delineation and rating for numerous deposit types; salable 

minerals sections; locatable mineral commodities not assessed
v

James J. Rytuba—Tract delineation, rating, and description for epithermal gold, silver, mercury, and gallium, volcanogenic uranium, gemstones, hectorite (lithium-rich clay), specialty clay, 

and zeolite deposits 

Brian N. Shaffer—Coal occurrences; figure construction

Lisa L. Stillings—Salable minerals sections; locatable mineral commodities not assessed

John C. Wallis—Figure construction

Colin F. Williams—Geothermal occurrences; figure construction

Douglas B. Yager—Potash occurrences

Lukas Zürcher—Tract delineation, rating, and description for intrusion-related deposits
vi

Contents

Acknowledgments........................................................................................................................................iii

Author Responsibilities................................................................................................................................iv

Geology and Mineral Resources of the Sheldon-Hart Mountain National Wildlife Refuge 

Complex (Oregon and Nevada), the Southeastern Oregon and North-Central Nevada, 

and the Southern Idaho and Northern Nevada (and Utah) Sagebrush Focal Areas............1

Executive Summary.......................................................................................................................................1

Purpose and Scope ..............................................................................................................................1

Geologic Framework ............................................................................................................................1

Locatable Mineral Commodities ........................................................................................................2

Assessment Tracts ...............................................................................................................................2

Leasable and Salable Mineral Commodities....................................................................................3

Introduction.....................................................................................................................................................4

Purposes of the Report ........................................................................................................................4

Organization and Terminology of this Report...................................................................................4

Description of Geology..................................................................................................................................7

Geologic Framework ............................................................................................................................7

Physiography................................................................................................................................7

Regional Geology and Tectonic Setting...................................................................................7

Geologic History...........................................................................................................................9

Paleozoic Continental Margin ..........................................................................................9

Mesozoic Magmatism and Crustal Shortening .............................................................9

Cenozoic Magmatism.......................................................................................................12

Cenozoic Structure and Sedimentary Basins ..............................................................16

Locatable Minerals......................................................................................................................................16

Leasable Minerals .......................................................................................................................................21

Oil and Gas...........................................................................................................................................21

Coal........................................................................................................................................................21

Potash...................................................................................................................................................21

Phosphate ............................................................................................................................................25

Geothermal...........................................................................................................................................25

Salable Minerals..........................................................................................................................................25

Mineral-Resource Potential of the Study Area for the Sheldon-Hart Mountain National Wildlife 

Refuge Complex Sagebrush Focal Area, Nevada and Oregon...............................................29

Introduction...................................................................................................................................................29

Description of Geology................................................................................................................................29

Mineral-Resource Potential.......................................................................................................................29

Mineral Deposit Types .......................................................................................................................29

Geology and Occurrence of Mineral Deposit Types.....................................................................29

Exploration and Mining Activity for Locatable Minerals..............................................................32

Mineral Potential of Locatable Minerals ........................................................................................38

Mineral Potential Tracts for Epithermal Gold, Silver, and Mercury Deposits...........................38

Buffering Epithermal Gold, Silver, and Mercury Tracts.......................................................38

Market Analyses of Gold, Silver, and Mercury..............................................................................42
vii

Mineral Potential Tracts for Gemstone Deposits and Lacustrine Diatomite Deposits............42

Market Analysis of Diatomite ...........................................................................................................43

Occurrence of Leasable Minerals ...................................................................................................43

Oil and Gas..................................................................................................................................43

Geothermal..................................................................................................................................43

Occurrence of Salable Minerals......................................................................................................43

Mineral-Resource Potential of the Study Area for the Southeastern Oregon and North-Central 

Nevada Sagebrush Focal Area, Nevada and Oregon..............................................................47

Introduction...................................................................................................................................................47

Description of Geology................................................................................................................................47

Mineral-Resource Potential.......................................................................................................................47

Mineral Deposit Types .......................................................................................................................47

Geology and Occurrence of Mineral Deposit Types.....................................................................50

Exploration and Mining Activity for Locatable Minerals..............................................................50

Mineral Potential of Locatable Minerals ........................................................................................61

Mineral Potential Tracts for Epithermal Gold, Silver, Mercury, and Gallium Deposits............61

Buffering Epithermal Mercury, Gold, Silver, and Gallium Tracts........................................78

Mineral Potential Tract for Volcanogenic Uranium Deposits......................................................78

Favorable Stratigraphy for Uranium Deposits ...............................................................................79

Mineral Potential Tract for Orogenic Low-Sulfide Gold-Quartz Vein Deposits ........................79

Market Analyses of Gold, Silver, Mercury, Gallium, and Uranium .............................................80

Mineral Potential Tract for Gemstone Deposits ............................................................................80

Mineral Potential Tracts for Hectorite (Lithium-Rich Clay) Deposits.........................................80

Mineral Potential Tracts for Specialty Clay Deposits ...................................................................81

Mineral Potential Tracts for Zeolite Deposits ................................................................................81

Mineral Potential Tracts for Lacustrine Diatomite Deposits .......................................................81

Market Analyses of Lithium, Zeolites, and Diatomite ...................................................................82

Occurrence of Leasable Minerals ...................................................................................................82

Oil and Gas..................................................................................................................................82

Geothermal..................................................................................................................................82

Potash..........................................................................................................................................82

Occurrence of Salable Minerals......................................................................................................83

Mineral-Resource Potential of the Study Area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area, Nevada, Idaho, and Utah ....................................................................89

Introduction...................................................................................................................................................89

Description of Geology................................................................................................................................89

Mineral-Resource Potential.......................................................................................................................89

Mineral Deposit Types .......................................................................................................................89

Geology and Occurrence of Mineral Deposit Types.....................................................................94

Exploration and Mining Activity for Locatable Minerals..............................................................94

Mineral Potential of Locatable Minerals ......................................................................................108

Mineral Potential Tracts for Epithermal Gold and Silver Deposits ...........................................108

Buffering Epithermal Gold and Silver Tracts .......................................................................153

Mineral Potential Tract for Hydroallogenic Uranium Deposits .................................................153

Stratigraphy Favorable for Uranium Deposits .............................................................................154
viii

Mineral Potential Tracts for Intrusion-Related Deposits, Including Porphyry Copper, 

Porphyry Molybdenum, Polymetallic Skarn, Replacement, and Vein, Tungsten 

Greisen Deposits, and Distal Disseminated Silver-Gold Deposits ..............................154

Rock Units Favorable for Intrusion-Related Deposits ................................................................167

Buffering Intrusion-Related Tracts .......................................................................................167

Mineral Potential Tracts for Volcanogenic Massive Sulfide Copper Deposits ......................168

Mineral Potential Tracts for Carlin-Type Gold Deposits.............................................................168

Stratigraphy Favorable for Black Shale Vanadium Deposits ....................................................170

Stratigraphy Favorable for Sedimentary Exhalative (SEDEX) Zinc-Lead-Silver-Gold 

Deposits ................................................................................................................................170

Stratigraphy Favorable for Mississippi Valley-Type (MVT) Lead and Zinc Deposits ............170

Market Analyses of Gold, Silver, Uranium, Copper, Molybdenum, Lead, Zinc, 

and Tungsten........................................................................................................................171

Mineral Potential Tracts for Lacustrine Diatomite Deposits .....................................................171

Mineral Potential Tracts for Bedded Barite Deposits.................................................................172

Market Analyses of Diatomite and Barite ....................................................................................172

Occurrence of Leasable Minerals .................................................................................................173

Coal.............................................................................................................................................173

Phosphate .................................................................................................................................180

Occurrence of Salable Minerals....................................................................................................181

Mineral-Resource Potential of the Nevada Additions Study Area ...................................................187

Introduction.................................................................................................................................................187

Description of Geology..............................................................................................................................187

Mineral-Resource Potential.....................................................................................................................187

Mineral Potential of Locatable Minerals ......................................................................................187

Exploration and Mining Activity for Locatable Minerals............................................................187

Occurrence of Leasable Minerals .................................................................................................188

Occurrence of Salable Minerals....................................................................................................189

References Cited........................................................................................................................................190

Appendix 1. Mineral-Potential Calssification System .........................................................................208

Level of Potential...............................................................................................................................208

Level of Certainty ..............................................................................................................................208

Reference Cited.................................................................................................................................208

Appendix 2. Mineral-Potential Assessment Tracts for Locatable Minerals ....................................210

Appendix 3. Locatable Mineral Commodities Not Assessed .............................................................211

Introduction........................................................................................................................................211

Locatable Metallic Mineral Commodities Not Assessed...........................................................211

Locatable Nonmetallic Mineral Commodities Not Assessed....................................................217

References Cited...............................................................................................................................219

Appendix 4. Oil and Gas Plays and Assessment Units ........................................................................222

Appendix 5. Dimensions of Epithermal Quartz-Adularia Gold-Silver Deposits in Northern 

Nevada...........................................................................................................................................223

References Cited...............................................................................................................................224
ix

Figures

 1. Surface land management map of the four USGS study areas that include three 

Sagebrush Focal Areas and the Nevada additions. USGS, U.S. Geological Survey.............5

 2. Physiographic map of the four USGS study areas that span the borders of Nevada, 

Oregon, Idaho, and Utah. USGS, U.S. Geological Survey...........................................................8

 3. Simplified geologic map and lithostratigraphic column of the four USGS study areas that 

span the borders of Nevada, Oregon, Idaho, and Utah, with stratigraphic and tectonic 

relationships in the area of the geologic map.............................................................................10

 4. Map showing Public Land Survey System (PLSS) sections that contain Bureau of Land 

Management (BLM) oil and gas leases and oil and gas exploration (dry) in the four 

 USGS study areas .............................................................................................................................22

 5. Map showing coal fields in the study area for Southern Idaho and Northern Nevada 

Sagebrush Focal Area......................................................................................................................23

 6. Map showing Bureau of Land Management (BLM) potash leases in the study area for the 

Southeast Oregon and North-Central Nevada Sagebrush Focal Area..................................24

 7. Map showing phosphate-bearing rocks in the study area for the Southern Idaho and 

Northern Nevada Sagebrush Focal Area.....................................................................................26

 8. Map showing Bureau of Land Management (BLM) geothermal leases, favorability, sites,

and systems in the four USGS study areas..................................................................................27

 9. Map showing proposed withdrawal areas that comprise the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon, and 

boundary of the U.S. Geological Survey (USGS) study area....................................................30

 10. Simplified geologic map of the study area for the Sheldon-Hart Mountain National Wildlife 

Refuge Complex Sagebrush Focal Area, Nevada and Oregon................................................31

 11. Map showing active and closed Bureau of Land Management (BLM) surface-management 

plans and notices for locatable mineral commodities in the study area for the SheldonHart Mountain National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and 

Oregon.................................................................................................................................................34

 12. Maps showing mining claims by Public Land Survey System (PLSS) section in the study 

area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush 

Focal Area, Nevada and Oregon....................................................................................................35

 13. Map showing mining districts and mine status in or near the study area for the SheldonHart Mountain National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and 

Oregon.................................................................................................................................................37

 14. Maps showing assessment tracts and level of resource potential for metallic and 

nonmetallic locatable minerals in the study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon................39

 15. Map showing Bureau of Land Management (BLM) oil and gas leases in the study area for 

the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal Area, 

Nevada and Oregon..........................................................................................................................44

 16. Map showing Bureau of Land Management (BLM) geothermal and sodium leases in the 

study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area, Nevada and Oregon...............................................................................45

 17. Map showing Bureau of Land Management (BLM) salable mineral commodity sites in the 

study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area, Nevada and Oregon...............................................................................46
x

 18. Map showing proposed withdrawal areas that comprise the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Nevada and Oregon, and boundary of 

the U.S. Geological Survey (USGS) study area......................................................................48

 19. Simplified geologic map of the study area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Nevada and Oregon.................................49

 20. Map showing active and closed surface-management plans and notices for locatable 

mineral commodities in the study area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Oregon and Nevada.................................52

 21. Maps showing mining claims by Public Land Survey System (PLSS) section in the study 

area for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, 

Nevada and Oregon ...................................................................................................................54

 22. Map showing mining districts, mine status, and active exploration areas in or near the 

study area for the Southeastern Oregon and North-Central Nevada Sagebrush Focal 

Area, Nevada and Oregon.........................................................................................................58

 23. Maps showing assessment tracts and level of resource potential for metallic and 

nonmetallic locatable minerals in the study area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Nevada and Oregon.................................62

 24. Map showing Bureau of Land Management (BLM) oil and gas, geothermal, and potash 

leases; oil and gas exploration (dry); and geothermal sites in the study area for the 

Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and 

Oregon ..........................................................................................................................................84

 25. Map showing Bureau of Land Management (BLM) salable mineral commodity sites in 

the study area for the Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Area, Nevada and Oregon..............................................................................................86

 26. Map showing proposed withdrawal areas that comprise the Southern Idaho and 

Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah, and boundary of 

the U.S. Geological Survey (USGS) study area......................................................................90

 27. Simplified geologic map of the study areas for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah; and the Nevada additions..92

 28. Map showing active and closed surface-management plans for locatable minerals in 

the study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Nevada and Oregon .................................................................................................................100

 29. Maps showing mining claims by Public Land Survey System (PLSS) section in the 

study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Nevada and Oregon .................................................................................................................102

 29. Maps showing mining claims by Public Land Survey System (PLSS) section in the 

study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Nevada and Oregon .................................................................................................................104

 30. Map showing mining districts, mine status, and active exploration areas in or near 

the study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Nevada, Idaho, and Utah.........................................................................................................106

 31. Maps showing assessment tracts for metallic locatable minerals and nonmetallic 

locatable minerals in the study area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area, Nevada, Idaho, and Utah...............................................................110

 32. Map showing Bureau of Land Management (BLM) oil and gas leases and gas 

exploration (dry) in the study area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah................................................174

 33. Map showing Bureau of Land Management (BLM) geothermal leases and sites in the 

study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Nevada, Idaho, and Utah.........................................................................................................176
xi

 34. Map showing coal fields in the study area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area, Idaho, Nevada, and Utah................................................178

 35. Map showing rocks containing phosphate in the study area for the Southern Idaho 

and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah.......................182

 36. Map showing Bureau of Land Management (BLM) salable mineral commodity sites in 

the study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Nevada, Idaho, and Utah.........................................................................................................184

 1-1. Matrix showing the classification system used for qualitative mineral-resource 

potential for locatable minerals in the Sagebrush Mineral-Resource Assessment.....209

Tables

 1. Locatable metallic (metals, metalliferous minerals) and nonmetallic (industrial) minerals, 

locatable or salable nonmetallic minerals, leasable minerals, salable minerals, and 

deposit types for locatable mineral commodities in the four USGS study areas ..............6

 2. Names, ages, and modal compositions of igneous intrusions, and additional adjacent 

igneous intrusions in the study areas for the Sheldon-Hart Mountain National 

Wildlife Refuge Complex, Southeastern Oregon and North-Central Nevada, and 

Southern Idaho and Northern Nevada Sagebrush Focal Areas.........................................13

 3. Mined deposits, with production, and resources of locatable mineral commodities 

within the USGS study areas ....................................................................................................17

 4. Type, number, and status of mining claims, leases for leasable mineral commodities 

(coal, geothermal, non-energy solid mineral, oil and gas leases), mineral material 

sales sites for salable mineral commodities, and surface-management plans in the 

proposed withdrawal area within the study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon............32

 5. Summary of active and closed mining claims for locatable minerals in Public Land 

Survey System (PLSS) sections that include the proposed withdrawal area within 

the study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area, Nevada and Oregon .........................................................................33

 6. Status and number of 43 Code of Federal Regulations (CFR) 3809 notices and plans of 

operations for locatable minerals in the proposed withdrawal area within the study 

area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush 

Focal Area, Nevada and Oregon..............................................................................................33

 7. Active 43 Code of Federal Regulations (CFR) 3809 notices and plans of operations 

summarized by locatable commodity in the proposed withdrawal area within the 

study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area, Nevada and Oregon .........................................................................33

 8. Mined deposits with production in the study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon............33

 9. Active (approved and pending) mineral material sales sites in the proposed withdrawal 

area within the study area for the Sheldon-Hart Mountain National Wildlife Refuge 

Complex Sagebrush Focal Area, Nevada and Oregon.........................................................43

 10. Type, number, and status of mining claims, leases, mineral material sales sites for 

salable mineral commodities, and surface-management plans in the proposed 

withdrawal area within the study area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Nevada and Oregon.................................51

 11. Summary of active and closed mining claims for locatable minerals in Public Land 

Survey System (PLSS) sections that are in the proposed withdrawal area within 

the study area for the Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Area, Nevada and Oregon..............................................................................................51
xii

 12. Status and number of surface-management plans for locatable minerals in the 

proposed withdrawal area within the study area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Nevada and Oregon.................................51

 13. Status and number of active surface-management plans in the proposed withdrawal 

area within the study area for the Southeastern Oregon and North-Central Nevada 

Sagebrush Focal Area, Nevada and Oregon, summarized by locatable commodity......51

 14. Mined deposits with production, and resources within and partly within the study area 

for the Southeastern Oregon and North-Central Nevada Focal Area ...............................60

 15. Active mineral material sales sites in the proposed withdrawal area within the study 

area for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, 

Nevada and Oregon ...................................................................................................................83

 16. Type, number, and status of mining claims, leases, mineral material sales sites for 

salable mineral commodities, and surface-management plans in the proposed 

withdrawal area within the study area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area, Idaho, Nevada, and Utah.................................................................95

 17. Summary of active and closed mining claims for locatable minerals in Public Land 

Survey System (PLSS) sections that include the proposed withdrawal area within 

the study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Idaho, Nevada, and Utah...........................................................................................................96

 18. Status and number of surface-management plans for locatable minerals in the 

proposed withdrawal area within the study area for the Southern Idaho and 

Northern Nevada Sagebrush Focal Area, Idaho, Nevada, and Utah.................................96

 19. Status and number of active surface-management plans in the proposed withdrawal 

area within the study area for the Southern Idaho and Northern Nevada Sagebrush 

Focal Area, Idaho, Nevada, and Utah, summarized by locatable commodity..................96

 20. Mined deposits with production and resources within, and partially within, the study 

area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, Idaho, 

Nevada, and Utah .......................................................................................................................97

 21. Active mineral material sales sites in the proposed withdrawal area within the study 

area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, Idaho, 

Nevada, and Utah .....................................................................................................................181

 22. Type, number, and status of mining claims, leases (coal, geothermal, non-energy solid 

mineral, oil and gas leases), mineral material sales sites, and 43 Code of Federal 

Regulations (CFR) 3809 plans in the proposed withdrawal area within the Nevada 

additions study area.................................................................................................................188

 23. Summary of active and closed mining claims for locatable minerals in Public Land 

Survey System (PLSS) sections that include the proposed withdrawal area within 

the Nevada additions study area ...........................................................................................189

 24. Status and number of 43 Code of Federal Regulations (CFR) 3809 plans of operations 

and notices for locatable minerals in the proposed withdrawal area within the 

Nevada additions study area..................................................................................................189

 25. Active mineral material sales sites in the proposed withdrawal area within the Nevada 

additions study area.................................................................................................................189

 3-1. Locatable metallic (metals, metalliferous minerals) and nonmetallic (industrial) 

minerals, locatable or salable nonmetallic minerals, leasable minerals, salable 

minerals, and deposit types for locatable mineral commodities in the four USGS 

study areas ................................................................................................................................212
xiii

[U.S. customary units to International System of Units]

Conversion Factors

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

yard (yd) 0.9144 meter (m)

Area

acre 4,047 square meter (m2

)

acre 0.4047 hectare (ha)

acre 0.4047 square hectometer (hm2

) 

acre 0.004047 square kilometer (km2

)

square foot (ft2

) 929.0 square centimeter (cm2)

square foot (ft2

) 0.09290 square meter (m2)

square inch (in2

) 6.452 square centimeter (cm2)

square mile (mi2

) 259.0 hectare (ha)

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

barrel (bbl; petroleum, 1 barrel=42 gal) 0.1590 cubic meter (m3

) 

Mass

ounce, troy (oz) 31.103 gram (g) 

pound, avoirdupois (lb) 0.4536 kilogram (kg) 

ton, short (2,000 lb) 0.9072 metric ton (t) 

ton, long (2,240 lb) 1.016 metric ton (t) 

[International System of Units to U.S. customary units]

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

kilometer (km) 0.5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Area

square meter (m2

) 0.0002471 acre 

square kilometer (km2

) 247.1 acre

square centimeter (cm2

) 0.001076 square foot (ft2)

square meter (m2

) 10.76 square foot (ft2) 

square centimeter (cm2

) 0.1550 square inch (ft2) 

square kilometer (km2

) 0.3861 square mile (mi2)

Volume

cubic meter (m3

) 6.290 barrel (petroleum, 1 barrel = 42 gal)

cubic meter (m3

) 264.2 gallon (gal) 

cubic meter (m3

) 0.0002642 million gallons (Mgal) 

cubic centimeter (cm3

) 0.06102 cubic inch (in3) 
xiv

Multiply By To obtain

cubic meter (m3

) 35.31 cubic foot (ft3)

cubic meter (m3

) 1.308 cubic yard (yd3) 

cubic kilometer (km3

) 0.2399 cubic mile (mi3) 

cubic meter (m3

) 0.0008107 acre-foot (acre-ft) 

Mass

gram (g) 0.032 ounce, troy (oz)

gram (g) 0.03527 ounce, avoirdupois (oz)

kilogram (kg) 2.205 pound avoirdupois (lb)

metric ton (t) 1.102 ton, short [2,000 lb]

metric ton (t) 0.9842 ton, long [2,240 lb]

Density

kilogram per cubic meter (kg/m3

) 0.06242 pound per cubic foot (lb/ft3) 

gram per cubic centimeter (g/cm3

) 62.4220 pound per cubic foot (lb/ft3) 

Supplemental Information

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as °F = (1.8 × 

°C) + 32.

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as °C = (°F – 

32) / 1.8.

Datum

Vertical coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.
xv

Abbreviations

Ad andradite (iron-rich garnet)

AMIS Automated Minerals Information System

AOC Assessment Oversight Committee

API American Petroleum Institute

AR “as received”

ASTER Advanced Spaceborne Thermal Emission and Reflection Radiometer

ASTM American Society for Testing and Materials

AU assessment unit (oil and gas)

BCF, BCFG billion cubic feet (of gas) 

BHT bottom-hole temperature

BLM Bureau of Land Management

BRW Bear River Watershed (Sagebrush Focal Area)

BV “best value”

CAGR compound annual growth rate

CAI color alteration index

CFR Code of Federal Regulations 

CIGS copper-indium-gallium selenide

CSA Canadian Standards Association

CSM clay-sulfate-mica

CSAMT controlled-source audiofrequency magnetotellurics

DLA Defense Logistics Agency

DOD U.S. Department of Defense

DOE U.S. Department of Energy

DOI U.S. Department of the Interior

EGS enhanced geothermal system

EIS Environmental Impact Statement

ETM+ Landsat 7 Enhanced Thematic Mapper Plus

FLPMA Federal Land Policy and Management Act of 1976

f.o.b. free on board

FWS U.S. Fish and Wildlife Service

g/t gram per metric ton

Ga giga-annum or billions of years ago

GFTZ Great Falls Tectonic Zone
xvi

GHC Geo-Heat Center

GIS geographic information system

HSSR Hydrogeochemical and Stream Sediment Reconnaissance

IDW inverse distance weighted

LEDs light-emitting diodes

LLD lower limit(s) of determination

m.y. millions of years

Ma mega-annum or millions of years ago

MAS Minerals Availability System

MCF thousand cubic feet of gas

MILS Mineral Industry Location System

MMBO million barrels of oil

MMBNGL million barrels of natural gas liquids

MOP muriate of potash

Moz million troy ounces

MRDS Mineral Resources Data System

Mt million metric tons

MTU metric ton unit

MVT Mississippi-Valley-type

MW megawatt

MWe megawatt electricity

NASGLP North American Soils Geochemical Landscape Project

NBMG Nevada Bureau of Mines and Geology

NDS National Defense Stockpile

NEPA National Environmental Policy Act of 1989

NGDB National Geochemical Database

NGL natural gas liquids

NGS National Geochemical Survey

NMIC USGS National Minerals Information Center

NOAA National Oceanic and Atmospheric Administration

NOGA USGS National Oil and Gas Assessment

NURE National Uranium Resource Evaluation

NWR National Wildlife Refuge

opt troy ounce per short ton

oz troy ounce 
xvii

PGE platinum-group element

PGM platinum-group metal

PLSS Public Land Survey System

ppm parts per million

REE rare earth element

REOE rare earth oxide equivalent(s)

RMOTC Rocky Mountain Oilfield Testing Center

ROD Record of Decision

RTP reduction-to-the-pole

SaMiRA Sagebrush Mineral-Resource Assessment

SEDAR Canadian System for Electronic Document Analysis and Retrieval

SEDEX sedimentary exhalative

SFA Sagebrush Focal Area

SG specific gravity

SI structural index

SOP sulfate of potash

SWIR shortwave-infrared (region of the electromagnetic spectrum)

t metric ton

TCM Tax Court Memorandum

Th/K thorium/potassium ratio

TMI total magnetic intensity

TOMS Topographically Occurring Mine Symbols

TPS total petroleum system

UMOS Utah Mineral Occurrence System

USBM former U.S. Bureau of Mines

USFS U.S. Forest Service

USGS U.S. Geological Survey

USMIN USGS Mineral Deposit Database

VMS volcanogenic massive sulfide

wt.% weight percent

WYO Southwestern and South-Central Wyoming (Sagebrush Focal Area)
xviii

Chemical Symbols and Formulas Used 

Ag silver Gd gadolinium

Al aluminum Ge germanium

Al2

O3 aluminum oxide H hydrogen

Ar argon H2

S hydrogen sulfide

As arsenic Hf hafnium

Au gold Hg mercury

B boron Ho holmium

Ba barium In indium

BaSO4 barium sulfate Ir iridium

Be beryllium K potassium

Bi bismuth K2

O potassium oxide

Br bromine La lanthanum

C carbon Li lithium

Corg organic carbon Lu lutetium

CO carbon monoxide Mg magnesium

CO2 carbon dioxide MgO magnesium oxide

Ca calcium Mn manganese

CaO calcium oxide Mo molybdenum

Cd cadmium N nitrogen

Ce cerium NH3 ammonia

CH4 methane Na sodium

Cl chlorine NaCl sodium chloride

Co cobalt Na2

O sodium oxide

Cr chromium Nb niobium

Cs cesium Nd neodymium

Cu copper Ni nickel

Dy dysprosium O oxygen

Er erbium Os osmium

Eu europium P phosphorous

F fluorine P4 elemental (white) phosphorus

Fe iron PO4 phosphate

Fe2

O3 ferric iron oxide P2O5 phosphorous pentoxide

Ga gallium Pb lead

GaAs gallium arsenide Pd palladium

GaN gallium nitride Pr praseodymium
xix

Pt platinum Te tellurium

Rb rubidium Th thorium

Re rhenium Ti titanium

Rh rhodium TiO2 titanium dioxide

Ru ruthenium Tm thulium

S sulfur Tl thallium

Sb antimony U uranium

Sc scandium U3

O8 triuranium octaoxide (yellowcake)

Se selenium V vanadium

Si silicon V2

O5 vanadium pentoxide

SiO2 silicon dioxide (silica) W tungsten

Sm samarium WO3 tungsten trioxide

Sn tin Y yttrium

Sr strontium Yb ytterbium

Ta tantalum Zn zinc

Tb terbium Zr zirconium

Mineral Formulas Used 

adularia KAlSi

3

O8

alunite KAl3(SO4)

2

(OH)

6

andradite (garnet) Ca3Fe3+

2

(SiO4)

3

ankerite Ca(Fe,Mg,Mn)(CO3)

2

argentite Ag2S

arsenopyrite FeAsS

barite BaSO4

bornite Cu5FeS4

cassiterite SnO2

chalcocite Cu2S

chalcopyrite CuFeS2

cinnabar HgS

clinoptilolite (zeolite) (Ca,Na,K)2-3Al3

(Al,Si)2Si13O36·12(H2O)

coffinite U[SiO4

,(OH)4]

corderoite Hg3

S2Cl2

dolomite CaMg(CO3)

2

erionite (zeolite) (Ca,Na,K)10[Al10Si26O72]·~30H2O
xx

fluorite CaF

2

galena PbS

hectorite (smectite clay) Na

3

(Mg,Li)

3

Si

4

O10(F,OH)

2

hematite Fe

2

O

3

ilmenite FeTiO

3

kaolinite Al

2

Si

2

O

5

(OH)

4

leucite K(AlSi

2

O

6

)

magnetite Fe

3

O

4

molybdenite MoS

2

molybdite MoO

3

monazite (Ce,La,Th,Nd)PO

4

montmorillonite (Na,Ca)0.33(Al,Mg)

2

(Si

4

O10)(OH)

2 · nH2

O

nepheline Na

3

KAl

4

Si

4

O16

opal SiO

2

·nH

2

O

phillipsite (zeolite) (Ca,Na,K)4-7[Al4-7Si2-9

O32]·12H

2

O

powellite CaMoO

4

pyrite FeS

2

quartz SiO

2

rutile TiO

2

scheelite CaWO

4

siderite FeCO

3

sillimanite Al

2

SiO

5

sylvite KCl

sylvinite KCl+NaCl

sphalerite (Zn,Fe)S

staurolite Fe

2

Al

9

Si

4

O23(OH)

stilpnomelane (K,Ca,Na)(Fe2+,Mg,Fe3+

)

8

(Si,Al)12(O,OH)27·nH

2

O

tetrahedrite (Cu,Fe,Ag,Zn)12Sb

4

S13

uraninite UO

2

xenotime YPO

4

zircon ZrSiO

4
Geology and Mineral Resources of the Sheldon-Hart 

Mountain National Wildlife Refuge Complex (Oregon and 

Nevada), the Southeastern Oregon and North-Central 

Nevada, and the Southern Idaho and Northern Nevada 

(and Utah) Sagebrush Focal Areas

By Peter G. Vikre, Mary Ellen Benson, Donald I. Bleiwas, Joseph P. Colgan, Pamela M. Cossette, Jacob DeAngelo, 

Connie L. Dicken, Ronald M. Drake II, Edward A. du Bray, Gregory L. Fernette, Jonathan M.G. Glen, Jon E. Haacke, 

Susan M. Hall, Albert H. Hofstra, David A. John, Stephen Ludington, Mark J. Mihalasky, James J. Rytuba, Brian N. 

Shaffer, Lisa L. Stillings, John C. Wallis, Colin F. Williams, Douglas B. Yager, and Lukas Zürcher

Executive Summary

Purpose and Scope

The U.S. Department of the Interior has proposed to withdraw 

approximately 10 million acres of Federal lands from mineral 

entry (subject to valid existing rights) from 12 million acres of 

lands defined as Sagebrush Focal Areas (SFAs) in Idaho, Montana, 

Nevada, Oregon, Utah, and Wyoming (for further discussion on 

the lands involved see Day and others, 2016). The purpose of the 

proposed action is to protect the greater sage-grouse (Centrocercus 

urophasianus) and its habitat from adverse effects of locatable 

mineral exploration and mining, subject to valid existing rights. 

This report addresses the mineral-resource potential of a subset of 

lands proposed for withdrawal. It summarizes the current status of 

locatable, leasable, and salable mineral commodities and assesses 

the potential of selected locatable minerals in lands proposed for 

withdrawal that span the Nevada, Oregon, Idaho, and Utah borders. 

 In this report, the four study areas evaluated by the U.S. 

Geological Survey (USGS) for the Sagebrush Mineral-Resource 

Assessment are (1) the Sheldon-Hart Mountain National Wildlife 

Refuge Complex Sagebrush Focal Area (943,866 acres [~3,820 

square kilometers, km2; 1,475 square miles, mi2]) in Washoe 

County, Nevada, and Harney and Lake Counties, Oregon; (2) the 

Southeastern Oregon and North-Central Nevada Sagebrush Focal 

Area (1,382,477 acres [~5,595 km2; 2,160 mi2]) in Humboldt 

County, Nevada, and Harney and Malheur Counties, Oregon; (3) 

the Southern Idaho and Northern Nevada Sagebrush Focal Area 

(3,734,263 acres [~15,112 km2

; 5,835 mi2]) in Cassia, Owyhee, 

and Twin Falls Counties, Idaho, Elko County, Nevada, and Box 

Elder County, Utah; and (4) the Nevada additions (394,289 

acres [~1,596 km2; ~616 mi2]) in Humboldt and Elko Counties, 

Nevada. Hereafter, we refer to these as the four USGS study 

areas. The charge to the USGS was to evaluate the proposed 

withdrawal areas, which are a subset of lands contained within the 

entire Sagebrush Focal Area. Because the detailed outline of the 

withdrawal areas are complicated and discontinuous, we chose 

to define the extent of our “study area” to the outer Public Land 

Survey System (PLSS) township boundary containing a given 

section of land within the withdrawal area. For a more detailed 

discussion see Day and others (2016).

Geologic Framework

The four study areas encompass the northern part of the 

Basin and Range physiographic province, a large, arid region of 

alternating north-trending rugged mountain ranges and low-relief 

intermontane basins. Parts of the study areas also cover the high 

lava plateaus of southern Idaho and the Nevada-California-Oregon 

border region. The Columbia Plateau physiographic province is 

characterized by subdued topography underlain by widespread, 

thick deposits of stratified volcanic rocks and isolated volcanic 

cinder cones. The study area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area includes the southwestern part of 

the Snake River Plain, a broad northeast-trending basin floored by 

basaltic lavas. The study areas drain largely to the north and then 

west via the Snake River, although the south flank of the study area 

for the Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Area drains to the south into the interior Humboldt River 

Basin in central Nevada.

Within the four study areas, the oldest rocks are Precambrian 

quartzite and schist and small quartz monzonite intrusions in the 

easternmost part of the study area for the Southern Idaho and 

Northern Nevada Sagebrush Focal Area; similar rocks may underlie 

Paleozoic shelf-slope sedimentary rocks (mostly carbonates) that 

crop out widely in the eastern part of this study area. Paleozoic 
2 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

rocks were overthrust, starting in the Late Devonian and continuing 

through the Mesozoic, by successively younger packages of 

deepwater marine sediments, which crop out in the central part 

of the study areas as the Roberts Mountains, Golconda, and 

Fencemaker allochthons. The far western part of the study areas

is mostly covered by Cenozoic volcanic rocks; basement there 

probably consists of Paleozoic sedimentary and Mesozoic volcanic 

arc rocks of the Black Rock and Pueblo terranes, which crop out 

between the study areas for the Sheldon-Hart Mountain National 

Wildlife Refuge Complex and Southeastern Oregon and NorthCentral Nevada Sagebrush Focal Areas.

Paleozoic and early Mesozoic sedimentary rocks throughout 

the study areas are intruded by Jurassic and Cretaceous granitic 

plutons emplaced during subduction of the Farallon Plate 

beneath western North America. Following a Late Cretaceous to 

early Tertiary hiatus, attributed to a change in subduction zone 

geometry, magmatism resumed with eruption of Eocene to early 

Miocene silicic to intermediate composition lava flows and tuffs. 

Beginning about 17 Ma, magmatism was dominated by bimodal 

basalt-rhyolite volcanism related to the Yellowstone Hot Spot. 

Miocene flood basalts, caldera-derived rhyolite ash-flow tuff, and 

rhyolite lava flows blanket much of the study areas. Extensional 

faulting has been ongoing since at least the middle Miocene, 

forming the present-day Basin and Range topography and creating 

numerous basins filled with sediments shed from the rising 

mountain ranges.

Locatable Mineral Commodities

Numerous locatable mineral commodities, including metallic 

and nonmetallic (also known as industrial) mineral commodities, 

occur in and near the four study areas. Many of these commodities 

have been mined, and numerous unmined deposits have been 

identified (resource; table 3). Metallic commodities (for example, 

copper, silver, and lead) commonly occur in several deposit types 

as determined by comparison to deposit type models, and two 

or more metals (for example, gold and silver) often have been 

produced from one deposit. Deposit types that occur in the study 

areas include epithermal gold, silver, and mercury, and gallium, 

gemstones, lacustrine diatomite, volcanogenic uranium, orogenic 

low-sulfide gold-quartz vein, hectorite (lithium-rich clay), 

specialty clays, zeolites, hydroallogenic uranium, Carlin-type 

gold, bedded barite, and numerous intrusion-related deposit types 

including porphyry copper, porphyry molybdenum, polymetallic 

skarn, replacement, and vein, tungsten greisen, and distal 

disseminated silver-gold. Favorable stratigraphy for lacustrine 

diatomite, intrusion-related, volcanogenic massive sulfide copper, 

Carlin-type gold, black shale vanadium, sedimentary exhalative 

zinc-lead-silver-gold, Mississippi Valley-type lead and zinc, and 

bedded barite deposits occurs in the study areas.

Forty-six locatable metallic and nonmetallic mineral 

commodities, and 14 commodities that are locatable or salable 

(depending largely on quality and value), were evaluated for 

assessment (table 1). Of these, 17 commodities were assessed that 

(1) occur as unmined resources, and (or) (2) have potential to occur 

in undiscovered deposits in each study area. Assessment of these 17 

commodities was based primarily on (1) deposits (mines, resources, 

prospects, and occurrences) containing the assessed commodity 

or commodities (table 3); (2) geological, geochemical, alteration, 

geophysical, and other characteristics of the deposits and deposit 

types which included the assessed commodity or commodities 

(appendix 2); (3) records of active and historical mining claims 

and surface-management plans provided by the Bureau of Land 

Management (BLM) and U.S. Forest Service (USFS); and (4) 

market analyses (appendix 5 and section I, Day and others, 2016). 

Locatable mineral commodities that were considered for assessment 

but were not assessed are briefly described in appendix 3.

Mineral potential assessment of the 17 commodities 

included (1) delineation of tracts that enclose rocks with favorable 

characteristics of deposit types (a) known to contain the assessed 

commodities, and (b) known to exist in the tract; (2) assignment 

of potential for undiscovered deposits in the tract (high, moderate, 

low, or none); and (3) assignment of relative certainty of mineral 

potential (A, least certain, to D, most certain). Tracts are described 

and justified in the separate report sections on each study 

area. Maps showing tract outlines and selected tract-defining 

characteristics accompany tract descriptions.

Assessment Tracts

In the study area for the Sheldon-Hart Mountain National 

Wildlife Refuge Complex Sagebrush Focal Area, tract SHEP01, 

Coyote Hills, has moderate potential (certainty level C) for 

epithermal gold, silver, and mercury deposits; tract SHEP02, 

Sheldon West, has moderate potential (certainty level B) for 

epithermal mercury deposits; and tract SHSS01, Dust Devil, 

has high potential (certainty level D) for sunstone deposits. 

Tract SHDT01, Washoe-Lake-Harney, encloses exposures of 

stratigraphic sections that contain lacustrine diatomite beds, and 

stratigraphy favorable for lacustrine diatomite deposits.

In the study area for the Southeastern Oregon and NorthCentral Nevada Sagebrush Focal Area, tract ONEP01, Cordero, 

has high potential (certainty level D) for epithermal mercury, 

gold, silver, and gallium deposits; tract ONEP02, Lucky Boy, 

has moderate potential (certainty level C) for epithermal mercury 

deposits; tract ONEP03, Buckskin, has high potential (certainty 

level D) for epithermal gold, silver, and mercury deposits; tract 

ONEP04, Paradise Valley, has moderate potential (certainty level 

C) for epithermal silver and gold deposits; tract ONVU01, Kings 

Valley, has high potential (certainty level D) for volcanogenic 

uranium deposits; tract ONOG01, Orovada, has moderate 

potential (certainty level C) for orogenic low-sulfide gold-quartz 

vein deposits; tract ONAG01, McDermitt Gemstones, has high 

potential (certainty level D) for semiprecious gemstone deposits; 

tract ONLI01, West Lith, has high potential (certainty level D) for 

hectorite (lithium-rich clay) deposits; tract ONLI02, Whitehorse 

Lithium, has moderate potential (certainty level B) for hectorite 

(lithium-rich clay) deposits; tract ONCL01, Colloid, has high 

potential (certainty level D) for specialty clay deposits; tract 

ONCL02, Whitehorse Clay, has moderate potential (certainty level 
Executive Summary 3

B) for specialty clay deposits; tract ONZE01, Nor Zeo, has high 

potential (certainty level D) for zeolite deposits; tract ONZE02, 

Whitehorse Zeolite, has moderate potential (certainty level C) 

for zeolite deposits; and tract ONDT01, Whitehorse Diatomite, 

has moderate potential (certainty level C) for lacustrine diatomite 

deposits. Tract ONDT02, Harney-Malheur, encloses exposures of 

stratigraphic sections that contain lacustrine diatomite beds and 

stratigraphy favorable for lacustrine diatomite deposits.

In the study area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area ten tracts have potential for 

epithermal gold, silver, and (or) mercury deposits: tract INEP01, 

Burner, moderate potential (certainty level C); tract INEP02, 

Cornucopia, moderate potential (certainty level C); tract INEP10, 

Good Hope, moderate potential (certainty level C); tract INEP03, 

Wood Gulch, high potential (certainty level D); tract INEP04, 

Jarbidge, high potential (certainty level D); tract INEP05, TJ, 

moderate potential (certainty level B); tract INEP06, Angel Wing, 

high potential (certainty level C); tract INE07, Oakley, high 

potential (certainty level D); tract INEP08, Star Lake, moderate 

potential (certainty level B); and tract INEP09, Gollaher, moderate 

potential (certainty level C). Tract INHU01, Racetrack, has high 

potential (certainty level D) for hydroallogenic uranium deposits. 

Five tracts have low potential (certainty level B); four of these 

have the word “permissive” in the tract name.

Fifteen tracts and tract groups (cospatial tracts assessed for 

several deposit types) were assessed with high to moderate potential 

(certainty levels B, C, and D ) for various intrusion-related deposits, 

including porphyry copper and molybdenum deposits, polymetallic 

(copper-lead-zinc-tungsten-silver-gold) skarn, replacement, and 

vein deposits, and distal disseminated silver-gold deposits: tract, 

INPR01, Pluton-related Permissive; tract INPR02, Mountain City 

Porphyry Copper, Mountain City Porphyry Molybdenum, and 

Mountain City Polymetallic Vein; tract INPR03, Cobb Creek; 

tract INPR04, Blue Jacket Polymetallic Replacement, Blue Jacket 

Polymetallic Vein, and Blue Jacket Tungsten Vein; tract INPR05, 

Alder Polymetallic Vein and Alder Tungsten-Molybdenum Skarn; 

tract INPR06, Island Mountain Distal Disseminated Gold-Silver 

and Island Mountain Polymetallic Vein and Skarn; tract INPR07, 

Charleston; tract INPR08, Elk Mountain Polymetallic Vein, Elk 

Mountain Copper Skarn, and Elk Mountain Tungsten-Molybdenum 

Skarn; tract INPR09, Contact Porphyry Copper, Contact Copper 

Skarn, Contact Tungsten Skarn, and Contact Polymetallic Vein; tract 

INPR10, Delano; tract INPR11, Indian Springs; tract INPR12, Gold 

Basin; tract INPR13, Texas Canyon; tract INPR14, Scraper Springs; 

tract INPR15, Ashbrook Polymetallic Replacement, Ashbrook Distal 

Disseminated Silver-Gold, and Ashbrook Polymetallic Vein.

Two tracts (including nested tracts) have potential for 

volcanogenic massive sulfide (VMS) copper deposits: tract 

INMS01, VMS Permissive, has low potential (certainty level B); 

and tracts INMS02 and INMS03, Rio Tinto 1 and Rio Tinto 2, 

have high potential (certainty levels D and C). 

Five tracts (including nested tracts) have potential for 

Carlin-type gold deposits: tract INCT01, Carlin Permissive, has 

low potential (certainty level B); tracts INCT02 and INCT03, 

Willow 1 and Willow 2, have moderate potential (certainty levels 

D and C); tracts INCT04 and INCT05, Big Springs 1 and Big 

Springs 2, have high potential (certainty levels D and C); tracts 

INCT06 and INCT07, Doby George 1 and Doby George 2, have 

high potential (certainty levels D and C); and tracts INCT08 and 

INCT09, North Star 1 and North Star 2, have moderate potential 

(certainty level D and C).

Four tracts have potential for lacustrine diatomite deposits: 

tract INDT01, Dickshooter, has high potential (certainty levelD); 

tract INDT02, Dickshooter North, has moderate potential 

(certainty level C); tract INDT03, Owyhee-Twin Falls, has 

moderate potential (certainty level B); and tract INDT04, OwyheeTwin Falls-Cassia-Elko, has low potential (certainty level B).

Two tracts (including nested tracts) have potential for 

bedded barite deposits: tract INBB01, Bedded-barite Permissive, 

has low potential (certainty level B); and tracts INBB02 and 

INBB03, Snake Mountains 1 and Snake Mountains 2, have high 

potential (certainty levels D and C).

In the study area for Nevada additions, no tracts were 

delineated and rated because there is insufficient evidence of 

mineral potential in much of the area. However, assessment tracts 

in the study area for Southeastern Oregon and North-Central 

Nevada Sagebrush Focal Area cover parts of the Nevada additions. 

These overlapping tracts are tract ONEP04, Paradise Valley; and 

tract ONOG01, Orovada. Tracts with low potential (favorable or 

permissive stratigraphy) for certain deposit types in the study area 

for the Southern Idaho and Northern Nevada Sagebrush Focal 

Area also extend into the Nevada Addition study area. These tracts 

consist of favorable stratigraphy for bedded barite, Carlin-type gold, 

lacustrine diatomite, volcanogenic massive sulfide copper, and 

intrusion-related deposits (porphyry copper, porphyry molybdenum, 

polymetallic [copper-lead-zinc-tungsten-silver-gold] skarn, 

replacement, and vein, and distal disseminated silver-gold deposits). 

Leasable and Salable Mineral Commodities

Leasable solid and fluid mineral commodities in the four 

study areas, including oil and gas, coal, potash, phosphate, borates, 

and geothermal (table 1), were qualitatively evaluated. None of 

these commodities has been produced within the study areas. There 

has been episodic exploration and leasing for oil and gas, coal, 

potash, phosphate, and geothermal, and favorable stratigraphy for 

these commodities exists in the four study areas. Two unmined coal 

fields and favorable stratigraphy for phosphate deposits that occur 

in and near the study area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area have low production potential 

because of low quality (value) and (or) quantity. 

Salable mineral commodities, or mineral materials, in the 

four study areas including common varieties (low unit value) 

of sand and gravel, aggregate, crushed rock, dimension stone, 

decorative stone, petrified wood, cinders, clay, and pumice 

(volcanic cinder), were qualitatively evaluated. There are 

numerous permits for salable commodities in the four study areas; 

most permits are for sand and gravel which has been produced 

from numerous sites. Other permits are for stone (including 

specialty, weathered, riprap, crushed, and dimension stone) 

gemstones, common clay, and pumice. 
4 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Introduction

The U.S. Department of the Interior has proposed to 

withdraw approximately 10 million acres of Federal lands 

identified within more than 165 million acres of lands defined as 

Sagebrush Focal Areas in Idaho, Montana, Nevada, Oregon, Utah, 

and Wyoming from mineral entry, subject to valid existing rights 

(U.S. Department of the Interior, 2015a,b). The purpose of the 

proposed action is to protect the greater sage-grouse (Centrocercus 

urophasianus) and its habitat from adverse effects of locatable 

mineral exploration and mining, subject to valid existing rights 

(Bureau of Land Management, 2015a,b,c). The Sagebrush Focal 

Areas consist of those public and National Forest System lands 

shown as Sagebrush Focal Areas on a map posted on the Bureau 

of Land Management (BLM) Web site (http://blm-egis.maps.

arcgis.com/apps/webappviewer/index.html?id=45b2d7896c364

67aac3990b739d75a26). In February 2016, the BLM requested 

assessments of two additional areas in Nevada, termed the 

“Nevada additions,” which lie to the south of the Southern Idaho 

and Northern Nevada Sagebrush Focal Area and the Southeastern 

Oregon and North-Central Nevada Sagebrush Focal Area (fig. 1). 

The proposed withdrawal areas within the three Sagebrush Focal 

Areas and the Nevada additions that span the borders of Nevada, 

Oregon, Idaho, and Utah encompass ~6,454,896 acres (~26,122 

square kilometers [km2

]; ~10,086 square miles [mi2]), of which, 

the BLM manages ~5,895,064 acres (~23,856 km2; ~9,211 mi2). 

The remaining land (~559,831 acres) is managed primarily by the 

U.S. Forest Service.

Purposes of the Report

The purposes of this report are to (1) assess the occurrence 

potential of deposits containing certain locatable mineral 

commodities, and (2) summarize the current status of locatable, 

leasable, and salable mineral commodities within four U.S. 

Geological Survey (USGS) study areas, including three Sagebrush 

Focal Areas that span the Nevada, Oregon, Idaho, and Utah 

borders, and the Nevada additions. The four USGS study areas 

include the Sheldon-Hart Mountain National Wildlife Refuge 

Complex Sagebrush Focal Area, the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, the Southern 

Idaho and Northern Nevada Sagebrush Focal Area, and the 

Nevada additions (fig. 1). The area studied includes the proposed 

withdrawal areas in southern Idaho, southern Oregon, northern 

Nevada, and northwestern Utah. The USGS study area boundaries 

coincide with Public Land Survey System (PLSS) townships 

that enclose parts of the proposed withdrawal area. The mineralresource potential of each study area is described in separate 

sections of this report.

Potential for occurrence of mineral deposits within 

the study areas was evaluated only for deposits of locatable 

mineral commodities. Locatable metallic and nonmetallic 

mineral commodities that were considered for evaluation are 

listed in table 1. A subset of those commodities was selected 

for assessment on the basis of commodities in mined deposits 

and unmined resources, and commodities that are the focus 

of current exploration programs within the four study areas. 

Assessed metallic mineral commodities are copper, gallium, 

gold, lead, lithium, mercury, molybdenum, silver, tungsten, 

uranium, and zinc. Assessed nonmetallic mineral commodities 

are barite, bentonite, diatomite, and zeolite. Deposit types in the 

study areas that contain the assessed metallic and nonmetallic 

mineral commodities include epithermal gold, silver, and 

mercury deposits, sunstone deposits, volcanogenic uranium 

deposits, hydroallogenic uranium deposits, lithium clay deposits, 

specialty clay deposits, a variety of intrusion-related porphyry and 

polymetallic deposits, Carlin-type gold deposits, volcanogenic 

massive sulfide (VMS) copper deposits, sedimentary exhalative 

(SEDEX) lead, zinc, and silver deposits, Mississippi Valley-type 

(MVT) lead and zinc deposits, lacustrine diatomite deposits, 

bedded barite deposits, zeolite deposits, and bentonite deposits 

(Day and others, 2016). 

This report was prepared as required by the Federal Land 

Policy and Management Act of 1976 (FLPMA; Pub. L. 94–579; 

90 Stat. 2743) for an application for withdrawal of lands. This 

report follows guidance provided in BLM Manual Sections 

3031 and 3060 for mineral assessments and mineral reports. 

The information and interpretations in this report do not 

include field examinations; instead, they are based on published 

descriptions (including documents available on Web sites) of 

stratigraphy, structure, mining districts, alteration, and exploration 

programs. The content of this report draws from the experience 

and knowledge of USGS geologists who have worked in the 

Sagebrush Focal Areas for more than 50 years.

Organization and Terminology of this Report

This report is based on guidance published in the BLM 

Manual Sections 3031 and 3060. To the extent possible, the 

information in this report has been organized to reflect BLM 

technical and legal language. Information and interpretations 

are organized by the types of mineral commodities defined by 

the BLM.

This report includes separate sections for each of the three 

Sagebrush Focal Areas, Sheldon-Hart Mountain National Wildlife 

Refuge Complex, Southeastern Oregon and North-Central Nevada, 

Southern Idaho and Northern Nevada, and for the Nevada additions, 

in which locatable mineral commodities were considered for 

assessment. Locatable mineral commodities that were assessed as 

numbered assessment tracts are grouped by deposit type on the basis 

of comparison to deposit type models (Day and others, 2016) in each 

study area. Leasable and salable mineral commodities that occur 

within the four study areas are broadly discussed in the following 

paragraphs. Deposits of several leasable mineral commodities are 

described in corresponding study area report sections.

Within the study areas, some lands, such as BLM wilderness 

study areas, have already been excluded from mineral entry. 

There are also inholdings of State and private lands within the 

study areas. Examples include the two sections set aside in every 

PLSS township to support State schools, mineral patents, and 
Introduction 

5

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CASSIA

COUNTY

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COUNTY GOODING

COUNTY

JEROME

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LINCOLN

COUNTY

MINIDOKA

COUNTY

OWYHEE

COUNTY

TWIN

FALLS

COUNTY

ELKO

COUNTY

HUMBOLDT

COUNTY

WASHOE

COUNTY

HARNEYCOUNTY

LAKE

COUNTY MALHEUR

COUNTY

BOX ELDER

COUNTY

CALIFORNIA

IDAHO

NEVADA

OREGON

UTAH

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114° 116° 118° 120°

43°42°

0 25 50 75 100 MILES0 25 50 75 100 KILOMETERS

Base modified from U.S. Geological Survey DEM data, 2016.Roads and political data copyright © 2014 Esri and its licensors.Boundary data from San Juan and others (2016).Surface Management data from BLM, 2015.USA Contiguous Albers Equal Area Conic Projection.Central meridian, 118° W., latitude of origin, 37.5° N.North American Datum of 1983.

Proposed withdrawal additions

Base data (in A and B)Base data (only in A)

USGS study area boundaryProposed withdrawal areas

USGS study area boundary(North-Central Idaho Study Area)

State boundariesCounty boundaries

Bureau of Land ManagementDepartment of DefenseDepartment of EnergyFish and Wildlife ServiceForest ServicePrivate LandsSheldon National Wildlife RefugeState Lands

EXPLANATION

A

B

Maparea

Study areas

IDAHO

MONTANA

OREGON WYOMING

UTAH NEVADA

WASHINGTON

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Focal area (only in B)

Surface management status (only in A)

Figure 1. Surface land management map of the four USGS study areas that include three Sagebrush Focal Areas and the Nevada additions. USGS, U.S. Geological Survey.
6 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Table 1. Locatable metallic (metals, metalliferous minerals) and nonmetallic (industrial) minerals, locatable or salable nonmetallic 

minerals, leasable minerals, salable minerals, and deposit types for locatable mineral commodities in the four USGS study areas. 

Locatable mineral commodities that were assessed are bold font. USGS, U.S. Geological Survey.

Locatable metals/ metalliferous minerals Locatable nonmetallic (industrial) minerals Leasable 

minerals Salable minerals

Aluminum Molybdenum Barite Borates, sodium Clay (common)

Antimony Nickel Bentonite Coal Sand and gravel

Beryllium Niobium (Columbium) Borates, calcium Geothermal Stone, building

Bismuth Platinum group metals Carbon Oil and gas Stone, crushed 

(aggregate)

Carbon Rare earth elements Diamond Phosphate Stone, dimension

Chromium Silicon Diatomite Potash —

Cobalt Silver Fluorspar (fluorite) Sodium —

Copper Tantalum Travertine — —

Gallium Tellurium Vermiculite — —

Germanium Thorium Zeolite — —

Gold Tin — — —

Iron Titanium — — —

Lead Tungsten — — —

Lithium Uranium — — —

Magnesium Vanadium — — —

Manganese Zinc — — —

Mercury Zirconium — — —

Deposit types for locatable commodities

Epithermal gold-silver (mercury) Lead-zinc skarn Volcanogenic massive sulfide

Basalt-hosted sunstone Polymetallic replacement Sedimentary-exhalative lead-zinc-silver 

(SEDEX)

Porphyry copper Polymetallic veins Bedded barite

Arc-related porphyry molybdenum (low-fluorine) Distal disseminated silver-gold (antimony) Mississippi Valley-type lead and zinc

Climax-type porphyry molybdenum Carlin-type gold (silver, mercury, antimony) Orogenic low-sulfide gold-quartz vein

Molybdenum-tungsten greisen Black shale vanadium Hectorite (lithium clay)

Copper skarn Hydroallogenic uranium Specialty clay

Tungsten skarn Volcanogenic uranium Zeolites

Classification based on quality

Locatable or salable nonmetallic (industrial) minerals, 

depending on quality

Quality criteria for locatable or salable determination

Building stone Salable; locatable if uncommon

Clay, specialty Locatable (for example, ceramic grade); otherwise salable

Garnet Locatable if high quality (for example, abrasive)

Gemstone Salable; locatable if uncommon (semi- and nonprecious)

Geodes Salable; locatable if uncommon

Gypsum Locatable if high quality (for example, optical grade)

Limestone Salable; locatable if high quality (for example, chemical, cement grade)

Mica Locatable if high quality (for example, large sheets, books)

Mineral specimens Locatable if uncommon

Perlite Locatable if high quality (for example, industrial or construction grade)

Pozzolan Salable; locatable if uncommon (for example, concrete additive specifications)

Pumice Salable; locatable if one dimension ≥2 inches

Silica and silica sand Salable; locatable if uncommon or high purity (for example, fracking proppant)

Stone, decorative Locatable; otherwise salable
Description of Geology 7

homesteads. With these exclusions, the proposed withdrawal areas 

have irregular and patchy shapes. To ensure complete coverage 

of the withdrawal areas, USGS used a study area that is made up 

of all the townships that include areas proposed for withdrawal. 

The townships include those first described by BLM (Bureau of 

Land Management, 2015c), as formally proposed by DOI (U.S. 

Department of the Interior, 2015a,b), plus amendments proposed 

by the State of Nevada (the “Nevada additions”) on January 15, 

2016 (http://gov.nv.gov/uploadedFiles/govnvgov/Content/News_

and_Media/Press/2016_Images_and_Files/Final Transmittal Letter 

1.15.16 Signed-reduced-combined.pdf), and further amended by 

BLM through correspondence (Anthony Titolo, BLM, written 

commun., April 22, 2016). 

Combinations of chemical, economic, geological, and 

legislated schemes are used to classify mineral commodities. 

Distinction is made between commodities mined or processed 

for metals (metallic) and those that are nonmetallic (nonmetallic 

or industrial). Another scheme differentiates commodities 

that are extracted out of solid rock (lode) from those that are 

concentrated in sediments by moving water (placer). Common 

variety mineral commodities are generally abundant and 

have wide application but relatively low unit value; they are 

largely mined from sites determined by transportation costs. 

Uncommon variety mineral commodities are relatively scarce 

(high unit value) and have specific qualities; their production 

is less sensitive to mining, processing, and transportation costs. 

Strategic and critical mineral commodities are distinguished 

by high importance to national security and prosperity. Other 

classification schemes distinguish mineral commodities on 

the basis of the source (for example, magma; sediments) 

and concentrating mechanism (for example, hydrothermal 

fluid; surface water) of the deposit containing the commodity 

of interest, resulting in deposits referred to as “magmatichydrothermal” and “placer,” for example.

The BLM differentiates “locatable,” “leasable,” and 

“salable” minerals. These legal terms, derived from the 

General Mining Act of 1872 (30 U.S.C.22–42), distinguish 

mineral commodities by the procedure required to enable 

their acquisition (ownership) and extraction on Federal lands. 

Locatable minerals include metallic mineral commodities as 

well as some uncommon varieties of industrial minerals with 

special qualities and uses. Rights to explore for, develop, 

and extract locatable mineral commodities can be acquired 

by U.S. citizens by claim location of tracts of public domain 

Federal lands. Claim location by lode (hard rock) and placer 

(unconsolidated sediments) claims is limited to 20 acres per 

claim, claim boundaries must be designated by appropriate 

monuments, and pre-existing claims must be avoided. Leasable 

minerals refer to mineral commodities that can be extracted 

under discretionary leases issued by the BLM (Mineral Leasing 

Act of 1920 [30 U.S.C. 181–287 et seq.]; the Geothermal 

Steam Act of 1970, as amended; or the Acquired Lands Act of 

1947, as amended). Examples of leasable mineral commodities 

include oil, gas, coal, oil shale, sodium, potash, phosphate, 

and all minerals within acquired lands. Salable minerals are 

those mineral commodities extracted under discretionary sales 

contracts between the producer and BLM (Mineral Materials 

Act of 1947 [30 U.S.C. 601 et seq.]). Salable minerals produced 

from sales sites are generally common variety, low unit value 

mineral commodities such as sand, gravel, and aggregate. 

Surface disturbance associated with mineral exploration and 

production must be approved and authorized according to 

surface-management notices and plans (43 Code of Federal 

Regulations [CFR] 3809 and 36 CFR 228 Subpart A).

Land use status of Federal lands within each of the study 

areas that span the borders of Nevada, Oregon, Idaho, and Utah, 

including number and type of claims, leases, sales sites, and 

surface-management (43 CFR 3809 and 36 CFR 228 Subpart A) 

authorizations, are tabulated in the study area report sections. 

Description of Geology

Geologic Framework 

Physiography

The Sheldon-Hart Mountain National Wildlife Refuge 

Complex, Southeastern Oregon and North-Central Nevada, 

and Southern Idaho and Northern Nevada Sagebrush 

Focal Areas, and the Nevada additions span the common 

borders of Nevada, Oregon, Idaho, and Utah. The four 

study areas encompass the northern parts of the Basin and 

Range physiographic province (fig. 2), a large, arid region 

of alternating north-trending rugged mountain ranges and 

low-relief intermontane basins. Parts of the study areas 

also cover the high lava plateaus of southern Idaho and the 

Nevada-California-Oregon border region. The Columbia 

Plateau physiographic province is characterized by subdued 

topography underlain by widespread, thick deposits of 

stratified volcanic rocks and isolated volcanic cinder cones. 

The study area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area includes the southwestern part of the 

Snake River Plain, a broad northeast-trending basin floored 

by basaltic lavas. The study areas drain largely to the north 

and then west via the Snake River, although the south flank of 

the study area for the Southeastern Oregon and North-Central 

Nevada Sagebrush Focal Area drains to the south into the 

interior Humboldt River Basin in central Nevada.

Regional Geology and Tectonic Setting

The geologic history of the study areas has been synthesized 

by Christiansen and Yeats (1992), Doebrich (1996), Wallace and 

others (2004), and Dickinson (2006, 2013). Pre-Cenozoic rocks 

can be divided into fault-bounded tectonostratigraphic packages 

that generally become younger westward across the study areas. 

The oldest rocks are Precambrian quartzite and schist that host 

small quartz monzonite intrusions in the easternmost part of the 

study area for the Southern Idaho and Northern Nevada Sagebrush 

Focal Area (Compton, 1972; Doelling and others, 1980); similar 
8 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah Goose Lake

LASSEN COUNTY

MODOC

COUNTY

ADA

COUNTY

CASSIA

COUNTY

ELMORE

COUNTY

GOODING

COUNTY LINCOLN COUNTY

JEROME

COUNTY

MINIDOKA

COUNTY

OWYHEE

COUNTY

TWIN

FALLS

COUNTY

ELKO

COUNTY

HUMBOLDT

COUNTY

WASHOE

COUNTY

HARNEYCOUNTY

LAKE

COUNTY MALHEUR

COUNTY

BOX ELDER

COUNTY

CALIFORNIA

IDAHO

NEVADA

OREGON

UTAH

114° 116° 118° 120°

43°42°

Base modified from U.S. Geological Survey DEM data, 2016.Physiography modified from N.M. Fenneman and D.W. Johnson (1946).Political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.Central meridian, 118° W., latitude of origin, 37.5° N.North American Datum of 1983.

0 25 50 75 100 MILES0 25 50 75 100 KILOMETERS

Physiography: division, province, section

Intermontane plateaus, Basin and Range, Great BasinIntermontane plateaus, Columbia Plateau, HarneyIntermontane plateaus, Columbia Plateau, PayetteIntermontane plateaus, Columbia Plateau, Snake River Plain

Base data

USGS study area boundary

USGS study area boundary(North-Central Idaho Study Area)

Proposed withdrawal areasState boundariesCounty boundaries

EXPLANATION

Maparea

Study areas

IDAHO

MONTANA

OREGON WYOMING

UTAH NEVADA

WASHINGTON

Snake River Plain

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Figure 2. Physiographic map of the four USGS study areas that span the borders of Nevada, Oregon, Idaho, and Utah. USGS, U.S. Geological Survey.
Description of Geology 9

rocks may underlie the Paleozoic shelf-slope sedimentary rocks 

(mostly carbonates) that crop out widely in the eastern part of this 

study area. Paleozoic rocks were overthrust, starting in the Late 

Devonian and continuing through the Mesozoic, by successively 

younger packages of deepwater marine sediments, which crop 

out in the central part of the study areas as the Roberts Mountains, 

Golconda, and Fencemaker allochthons. The far western part of 

the study areas is mostly covered by Cenozoic volcanic rocks, but 

basement there probably consists of Paleozoic sedimentary and 

Mesozoic volcanic arc rocks of the Black Rock (Darby and others, 

2000) and Pueblo terranes, which crop out between the study areas 

for the Sheldon-Hart Mountain National Wildlife Refuge Complex 

and Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Areas.

Paleozoic and early Mesozoic sedimentary rocks throughout 

the study areas are intruded by Jurassic and Cretaceous granitic 

plutons emplaced during subduction of the Farallon Plate 

beneath western North America. Following a Late Cretaceous to 

early Tertiary hiatus, attributed to a change in subduction zone 

geometry, magmatism resumed with eruption of Eocene to early 

Miocene silicic to intermediate composition lava flows and tuffs. 

Beginning about 17 Ma, magmatism was dominated by bimodal 

basalt-rhyolite volcanism related to the Yellowstone Hot Spot. 

Miocene flood basalts, caldera-derived rhyolite ash-flow tuff, and 

rhyolite lava flows blanket much of the study areas. Extensional 

faulting has been ongoing since at least the middle Miocene, 

forming the present-day Basin and Range topography and creating 

numerous basins filled with sediments shed from the rising 

mountain ranges.

Geologic History

Paleozoic Continental Margin

Precambrian basement rocks are exposed in a few ranges 

just east, southeast, and south of the study areas (Compton and 

others, 1977), and are presumed to represent the basement of the 

Paleozoic continental shelf sequence that is widely exposed in 

northeastern Nevada. The initial 87Sr/86Sr = 0.706 isopleth, which 

is generally considered to mark the boundary between continental 

crust to the east and oceanic or transitional crust to the west 

(Kistler and Peterman, 1978; Tosdal and others, 2000), trends 

northerly through central Nevada but bends eastward in northern 

Nevada, which relegates the majority of the study areas to a 

position west of the rifted continental margin (fig. 3).

Deposition of carbonate and siliciclastic sedimentary rocks 

in eastern Nevada, western Utah, and southwestern Idaho began 

in the Neoproterozoic and continued through the Triassic to Early 

Jurassic. These rocks were deposited in shelf, slope, and foreland 

basin environments along the western margin of North America 

and constitute a westward-thickening wedge composed of shale, 

limestone, dolomite, quartzite, conglomerate, and other siliciclastic 

rocks that reaches an aggregate thickness of more than 10 km. 

Carbonate units in this sequence are potential skarn host rocks, 

and the lower Paleozoic carbonates are of particular importance 

because they host large tonnage Carlin-type gold deposits 

throughout northern Nevada (Willden, 1964; LaPointe and others, 

1991; Doebrich, 1996; Wallace and others, 2004). 

During the middle Paleozoic and Mesozoic, shelf and 

slope rocks were overthrust by successive packages of deeper 

water rocks that young from east to west. The oldest package is 

the Roberts Mountains allochthon, a highly deformed sequence 

of lower Paleozoic chert, argillite, quartzite, and greenstone 

widely exposed in northeastern Nevada. The Roberts Mountains 

allochthon was thrust eastward over coeval shelf and slope strata 

during the Late Devonian–Mississippian Antler orogeny along the 

regionally extensive Roberts Mountains thrust (Roberts and others, 

1958; Stewart, 1980). Throughout northern Nevada, rocks of the 

Roberts Mountains allochthon host a variety of epigenetic mineral 

deposits (Willden, 1964; LaPointe and others, 1991).

The Golconda allochthon is a highly deformed package of 

Mississippian to Permian chert, argillite, shale, and mafic volcanic 

rocks deposited in an ocean basin and now exposed throughout 

north-central Nevada (for example, Silberling and Roberts, 1962; 

Brueckner and Snyder, 1985; Murchey, 1990). These rocks were 

thrust eastward over the Roberts Mountains allochthon and its 

Pennsylvanian-Permian overlap sequence along the Golconda 

thrust during the late Permian-Early Triassic Sonoma orogeny (for 

example, Miller and Miller, 1991). Rocks within the Golconda 

allochthon, especially those south of the study areas, contain 

diverse types of syngenetic and epigenetic mineral deposits 

(Willden, 1964; LaPointe and others, 1991).

Mesozoic Magmatism and Crustal Shortening

During the Triassic, a thick sequence of fine-grained 

sedimentary and minor carbonate rocks accumulated in a back-arc 

basin in what is now western Nevada. The lower part includes 

carbonate-rich rocks deposited on the continental shelf, whereas 

the upper part, rocks of the Auld Lang Syne Group (Burke and 

Silberling, 1973), consists of pelitic turbidite flows deposited as 

submarine fan deposits in a subsiding marine basin (Compton, 

1960; Oldow and others, 1990; Wyld, 2002). The siliciclastic 

rocks, part of the Fencemaker allochthon of the LuningFencemaker fold and thrust belt (Oldow and others, 1990; Wyld 

and Wright, 2001; Wyld and others, 2003), were thrust eastward 

over carbonate shelf strata during the Early to Middle Jurassic, 

isoclinally folded, and metamorphosed to greenschist facies. 

Fencemaker allochthon rocks host polymetallic vein deposits 

and epithermal precious metal and antimony veins in the Santa 

Rosa Range (Willden, 1964; Doebrich, 1996). Middle Jurassic 

deformation in eastern Nevada and western Utah, some structures 

of which lie within the southeastern part of figure 3A (Thorman 

and Peterson, 2011), is in part coeval with the Luning-Fencemaker 

fold and thrust belt.

The Pine Forest Range, Jackson Mountains, and Pueblo 

Mountains in northwestern Nevada expose Triassic to Middle 

Jurassic magmatic arc rocks and underlying Paleozoic 

basement assigned to the Black Rock and Pueblo terranes 

(Oldow, 1984; Silberling, 1991; Wyld and Wright, 2001), 

including lava flows, hypabyssal intrusive rocks, volcaniclastic 
10 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah Goose Lake

114° 116° 118° 120°

43°42°

CALIFORNIA

IDAHO

NEVADA

OREGON

UTAH

114° 116° 118° 120°

43°42°

Maparea

Study areas

IDAHO

MONTANA

OREGON WYOMING

UTAH NEVADA

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.Political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.Central meridian, 118° W., latitude of origin, 37.5° N.North American Datum of 1983.

0 25 50 75 100 MILES0 25 50 75 100 KILOMETERS

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

EXPLANATION

Base data

USGS study area boundaryState boundaries

Black Rock terrane (Triassic to Devonian)

Mesozoic granitic rocks (Cretaceous and Jurassic)

Pueblo terrane (Jurassic)

Golconda allochthon (Permian to Mississippian)Roberts Mountains allochthon (Devonian to Cambrian)Sedimentary rocks of the North Americancontinental shelf (Triassic to Neoproterozoic)Metamorphic rocks (Paleozoic and Neoproterozoic)Precambrian basement rocks (Proterozoic and Archean)

Surfical deposits (Quaternary)Volcanic rocks (Quaternary)

Fencemaker allochthon (Triassic) Mafic to intermediate lava flows (Pliocene and Miocene)

Rhyolite tuffs and lava flows (Pliocene and Miocene)Sedimentary rocks (Pliocene and Miocene)Volcanic and sedimentary rocks (early Miocene to Eocene)Intrusive rocks (Tertiary)

Generalized lithologic units (geologic age)

Proposed withdrawal additions

USGS study area boundary(North-Central Idaho Study Area)

Nevada additions

A

Figure 3. Simplified geologic map (

A) and lithostratigraphic column (

B) of the four USGS study areas that span the borders of Nevada, Oregon, Idaho, and Utah. USGS, U.S. Geological Survey. 

B, 

Stratigraphic and tectonic relationships in the area of the geologic map. Map was synthesized from state geologic maps of Nevada, Oregon, Idaho, California, and Utah (Jennings and others, 1977; Walker and MacLeod, 1991; Hintze and others, 2000; Saucedo and others, 2000; Miller and others, 2002; Crafford, 2007; Lewis and others, 2012).
Description of Geology 11

Roberts Mtns. thrust

Golconda thrust

?

Paleozoic Mesozoic Cenozoic

Paleogene Neogene

Eocene Oligocene Miocene

ERAPERIODEPOCH Pliocene

Quaternary

Pleistocene

550

500

450

400

350

300

250

200

150

100

50

40

30

10

20

5

4

3

2

1

0 Holocene Paleocene

WEST Distribution of pre-Tertiary rocks EAST Black Rock terrane

Pueblo

terrane

Jurassic and Cretaceous granitic rocks

Millions of years before present (Ma)

Sedimentary rocks

Silicic tuffs and lavas

Mafic to intermediate lavas

Volcanic and

sedimentary rocks

Intrusive rocks

Surficial

deposits

Note scale changes at 50 and 5 Ma. Volcanic

rocks

Fencemaker

allochthon

Golconda allochthon

Roberts Mountains allochthon 

Sedimentary rocks of the North American continental shelf



O

S

D

M



P



J

K

Black Rock terrane (Triassic to Devonian)

Mesozoic granitic rocks (Cretaceous

 and Jurassic)

Pueblo terrane (Jurassic)

Sedimentary rocks of the North American

 continental shelf (Triassic 

 to Neoproterozoic)

Golconda allochthon (Permian 

 to Mississippian)

Roberts Mountains allochthon

 (Devonian to Cambrian)

Surfical deposits (Quaternary)

Volcanic rocks (Quaternary)

Fencemaker allochthon (Triassic)

Intrusive rocks (Tertiary)

Rhyolite tuffs and lava flows

 (Pliocene and Miocene)

Sedimentary rocks (Miocene and Pliocene)

Mafic to intermediate lava flows 

 (Pliocene and Miocene)

Volcanic and sedimentary rocks

 (early Miocene to Eocene)

EXPLANATION

Generalized litho-tectonic units (geologic age)

B

Figure 3. Simplified geologic map (A) and lithostratigraphic column (B) of the four USGS study areas that span the borders of Nevada, Oregon, Idaho, 

and Utah. USGS, U.S. Geological Survey. B, Stratigraphic and tectonic relationships in the area of the geologic map. Map was synthesized from state 

geologic maps of Nevada, Oregon, Idaho, California, and Utah (Jennings and others, 1977; Walker and MacLeod, 1991; Hintze and others, 2000; Saucedo 

and others, 2000; Miller and others, 2002; Crafford, 2007; Lewis and others, 2012).—Continued
12 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

rocks, clastic sedimentary rocks, and limestone (Wyld, 

1996; Quinn and others, 1997). These rocks do not crop out 

within the study areas but probably represent basement to the 

volcanic rocks that underlie the study area for the SheldonHart Mountain National Wildlife Refuge Complex Sagebrush 

Focal Area.

Mesozoic igneous activity in the study areas was 

fundamentally driven by subduction of the Farallon Plate beneath 

the western edge of North America, which caused continental 

arc magmatism. Jurassic magmatism was dominated by the 

large granodiorite intrusion near Contact, Nevada (table 2). 

Several additional, very small volume Jurassic stocks and plugs 

are distributed across northern Nevada. Compositions of these 

intrusions (Streckeisen, 1976) range from granite to diorite, though 

medium- to coarse-grained granite and granodiorite are most 

common (fig. 3A; table 2).

Cretaceous granitic magmatism produced numerous, large, 

holocrystalline granitic intrusions distributed across northern 

Nevada and southern Idaho (table 2; fig. 3A). Compositions 

of these medium- to coarse-grained Cretaceous intrusions are 

almost exclusively granite to granodiorite. Porphyry copper and 

molybdenum (Seedorff and others, 2005), skarn (Meinert and 

others, 2005), and polymetallic vein and replacement deposits 

(Willden, 1964; LaPointe and others, 1991) are closely related to 

Cretaceous intrusions throughout the study areas.

Cretaceous convergence between the Farallon and North 

America Plates led to crustal shortening over a broad area of the 

western United States known as the Sevier fold and thrust belt 

(for example, Armstrong, 1968; DeCelles, 2004). Paleozoic and 

lower Mesozoic rocks in eastern Nevada and western Utah were 

deformed in the hinterland of this belt, primarily into open, upright 

folds. These structures generally trend north, but bend to an easttrending orientation along the Idaho border in the study area for 

the Southern Idaho and Northern Nevada Sagebrush Focal Area. 

Magmatism and deformation ceased in the Late Cretaceous as 

the angle of the subducting slab is inferred to have shallowed and 

extinguished the Cretaceous arc (for example, Humphreys and 

others, 2003). 

Cenozoic Magmatism

Following Late Cretaceous to early Cenozoic magmatic and 

tectonic quiescence, magmatism in northern Nevada and southern 

Idaho resumed in the Eocene and migrated south and west across 

Nevada during the Oligocene and early Miocene. Southwardsweeping middle Tertiary magmatism is generally attributed to 

progressive rollback or delamination of the formerly shallow 

Farallon slab (for example, Humphreys and others, 2003). In the 

study areas, slab rollback magmatism is largely restricted to rocks 

erupted about 43–22 Ma (Ludington and others, 1996) in a small 

area north of Elko, Nevada, and to rocks erupted about 38–24Ma 

in northwestern Nevada (Colgan and others, 2006b; Lerch and 

others, 2008). These rocks include voluminous ash-flow tuffs 

erupted from calderas in northeastern Nevada (Henry and John, 

2013), tuffaceous sediments, flow dome complexes, andesitic lava 

flows, and volumetrically minor intrusive rocks. Small, Eocene 

to Oligocene stocks at Mount Neva and Fourmile Creek (table 2), 

just south of the study area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area, are composed of granodiorite and 

rhyolite to dacite, respectively (du Bray and Crafford, 2007). The 

close temporal, spatial, and inferred genetic relations between 

Eocene intrusions in north-central Nevada and Carlin-type gold 

deposits have been documented by Ressel and Henry (2006) and 

Muntean and others (2011).

In contrast, some Cenozoic volcanic rocks in the study area 

for the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area reflect magmatism related to the ancestral 

Cascades Arc (du Bray and others, 2014). These rocks are 

consistent with steepening subduction and continued southwestdirected slab rollback that localized magmatism progressively 

further to the southwest (Dickinson, 2006). The ancestral Cascades 

Arc was established as a north-northwest-trending array of 

magmatic centers, principally composite volcanoes, lava dome 

complexes, and less common shield volcanoes, extending to the 

southeast from south-central Oregon. Ancestral Cascades Arc 

rocks in the Coyote Hills and Warner Mountains, in and near 

the study area for the Sheldon-Hart Mountain National Wildlife 

Refuge Complex Sagebrush Focal Area, include Oligocene to 

Miocene basalt, andesite, and rhyolite erupted from composite 

and shield volcanoes or flow dome complexes (Thomas, 1981; 

Colgan and others, 2011). Volcanic rocks in the Warner Mountains 

and Coyote Hills are associated with epithermal mineralization 

in the High Grade (Keats, 1985) and Lost Cabin (Thomas, 1981) 

districts, respectively.

Most Cenozoic igneous rocks in the study areas are Miocene 

to Holocene basalt and rhyolite erupted after about 17Ma. 

Voluminous bimodal Miocene volcanism in this region is generally 

attributed to west-southwest-directed passage of the North 

American Plate over the Yellowstone Hot Spot (for example, Pierce 

and Morgan, 1992). The earliest eruptions attributed to the hot spot 

are voluminous basaltic lava flows of the Steens–Columbia River 

flood basalt province. Between about 16.6 and 15.0 Ma, about 

235,000 cubic kilometers (km3) of basaltic lava was erupted from 

fracture zones in the vicinity of the Oregon-Idaho border (Camp 

and Ross, 2004; Camp and Hanan, 2008), and flowed across large 

parts of what is now southeastern Oregon and northwestern Nevada. 

Similar age basalt flows and dikes form the northern Nevada rift, 

which extends south-southeast from the northern Santa Rosa Range 

across the study area for the Southeastern Oregon and NorthCentral Nevada Sagebrush Focal Area (Zoback and others, 1994; 

John and others, 2000).

Basaltic volcanism was closely followed by eruptions 

of rhyolite tuffs and lava flows, forming the 16.5 to 15.5 Ma 

McDermitt and High Rock caldera complexes (Rytuba and 

McKee, 1984; Coble and Mahood, 2016) and Santa Rosa–

Calico volcanic field (Breuseke and Hart, 2009) in northwestern 

Nevada and southeastern Oregon. Voluminous flows of the 

Jarbidge Rhyolite also blanketed much of the Nevada-Idaho 

border area about 16 to 15 Ma (Brueseke and others, 2014). 

Caldera-forming eruptions migrated northeast from northwest 

Nevada, along the Snake River Plain, becoming progressively 

younger as the North American Plate moved over the stationary 
Description of Geology 13

Table 2. Names, ages, and modal compositions of igneous intrusions, and additional adjacent igneous intrusions in the study areas for 

the Sheldon-Hart Mountain National Wildlife Refuge Complex, Southeastern Oregon and North-Central Nevada, and Southern Idaho and 

Northern Nevada Sagebrush Focal Areas.

A. Names, ages, and modal compositions of igneous intrusions, listed from youngest to oldest. 

[Polygon centroids identify the central points of all mapped polygons associated with an individual intrusion. ID, Idaho; NV, Nevada; UT, Utah]

Intrusion name State Age (Ma) Modal composition Polygon centroid(s) References

Buckskin Mountain NV 16 Rhyolite −117.5574, 41.7912 du Bray, 2007; Vikre, 2007

Canyon Creek NV 16 Rhyolite −117.5904, 41.7079 du Bray, 2007; Vikre, 2007

Hinkley Summit NV 16 Dacite −117.5315, 41.6510 du Bray, 2007; Brueseke and Hart, 2009

National NV 16 Rhyolite −117.5882, 41.7767 du Bray, 2007; Vikre, 2007

Wildhorse NV Tertiary Granite −115.9335, 41.6492 du Bray, 2007

Red Butte UT 25 Monzogranite −113.7592, 41.7031; 

−113.7607, 41.6744

Miller and others, 2012

Almo ID 29 Granite −113.8563, 42.0612; 

−113.7131, 42.0738; 

−113.6774, 42.1423;

−113.6323, 42.1435; 

−113.7063, 42.1216; 

−113.8319, 42.0130; 

−113.7271, 42.0145

Miller and others, 2008

Bearpaw Mountain NV 75 Granite −115.5719, 41.9317 du Bray, 2007

Skull Creek NV 83 Granite −116.0238, 41.9330; 

−116.0059, 41.9525

du Bray, 2007

Castle Creek ID 87–60 Granodiorite −116.4044, 42.8199; 

−116.4077, 42.7661

Ekren and others, 1981

Cottonwood Creek west NV; ID 91–88 Granodiorite −115.8520, 41.9756; 

−115.8211, 41.9968; 

−115.8403, 41.9741; 

−115.8294, 42.0017

du Bray, 2007

McDonald Creek NV 91 Granodiorite −115.9383, 41.9173; 

−115.8307, 41.9216

du Bray, 2007

Mountain City NV 93 Granite −115.8628, 41.8388; 

−115.8405, 41.8321; 

−115.8482, 41.8509; 

−115.9064, 41.8589

du Bray, 2007

White Elephant Butte NV 100 Granodiorite −115.0757, 41.8957 du Bray, 2007

Bilk Creek NV 105 Granite-quartz 

monzonite

−118.4692, 41.8715; 

−118.5710, 41.9081

du Bray, 2007; Colgan and others, 2006b

Coffeepot NV 105–93 Granite −115.5422, 41.8259; 

−115.6408, 41.8321

du Bray, 2007

Santa Rosa NV 105 Granodiorite −117.6653, 41.5335 du Bray, 2007; Colgan and others, 2006b

Enright Hill NV 110 Granodiorite −115.8095, 41.8897; 

−115.8165, 41.8877

du Bray, 2007

Indian Springs NV 139–137 Monzogranitegranodiorite−114.2518, 41.6284 du Bray, 2007

Horse Heaven NV Cretaceous Granite −115.8856, 41.9431; 

−115.8775, 41.9551; 

−115.8649, 41.9671

du Bray, 2007

Long Canyon Copper Mountains NV Cretaceous Granite −115.6157, 41.9684 du Bray, 2007

Silver Creek NV Cretaceous Granite −116.0846, 41.7446 du Bray, 2007

Trail Creek NV Cretaceous Granodiorite −116.0541, 41.6920 du Bray, 2007

White Rock NV Cretaceous Quartz diorite −116.1196, 41.7003; 

−116.1387, 41.7007

du Bray, 2007

Columbia NV 150 Quartz diorite −116.0574, 41.6711; 

−116.0684, 41.6814; 

−116.1615, 41.7049

du Bray, 2007
14 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Table 2. Names, ages, and modal compositions of igneous intrusions, and additional adjacent igneous intrusions in the study areas for 

the Sheldon-Hart Mountain National Wildlife Refuge Complex, Southeastern Oregon and North-Central Nevada, and Southern Idaho and 

Northern Nevada Sagebrush Focal Areas.—Continued

Intrusion name State Age (Ma) Modal composition Polygon centroid(s) References

Contact NV 156–124 Granodiorite −114.7755, 41.7442; 

−114.5474, 41.7760; 

−114.8065, 41.7587; 

−114.6636, 41.7399

du Bray, 2007

Cottonwood Creek east NV Jurassic Diorite −115.1891, 41.7945 du Bray, 2007

Hammond Canyon NV 156 Granite −115.7327, 41.7327 du Bray, 2007

Ninemile Mountain NV Jurassic Granodiorite −114.4584, 41.4747 du Bray, 2007

Seventy Six Creek NV Jurassic Granite −115.4950, 41.6987; 

−115.4872, 41.7056; 

−115.5053, 41.7123

du Bray, 2007

Ingham Peak UT Precambrian Metamorphosed 

quartz monzonite

−113.6113, 41.7024; 

−113.7333, 41.7071;

−113.7536, 41.7696

Doelling and others, 1980

Vipont Mountains UT Precambrian Metamorphosed 

quartz monzonite

−113.7853, 41.8827 Doelling and others, 1980

Granite Peak Santa Rosa NV TertiaryCretaceousGranodiorite −117.5991, 41.6696 du Bray, 2007

Buttermilk Creek NV TertiaryCretaceousGranodiorite −117.4909, 41.5879 du Bray, 2007

Sawtooth NV Cretaceous Granodiorite −117.7467, 41.5739 du Bray, 2007

Disaster Peak NV Cretaceous Granodiorite-quartz 

diorite

−118.2699, 41.9724; 

−118.2025, 41.9004

du Bray, 2007

Trident Peak NV; OR Cretaceous Granodiorite −118.3413, 41.8178; 

−118.3321, 41.8366; 

−118.3467, 41.8487; 

−118.4261, 41.8928; 

−118.3869, 41.9058

du Bray, 2007

B. Additional adjacent igneous intrusions.

[ID, Idaho; NV, Nevada; UT, Utah]

Intrusion name State Age (Ma) Modal composition Polygon centroid(s) References

McGinty UT 37 Monzogranite to 

granodiorite

−114.0344, 41.3083 Miller and others, 1987

Fourmile Creek NV OligoceneEoceneRhyolite-dacite −116.4720, 41.4035; 

−116.4612, 41.4052

du Bray, 2007

Mount Neva NV 39 Granodiorite −116.3566, 41.3179; 

−116.3436, 41.3228; 

−116.3344, 41.3231; 

−116.3186, 41.3262; 

−116.3577, 41.3267; 

−116.3573, 41.3498

du Bray, 2007

Rocky Pass UT Tertiary Quartz monzonite −113.6299, 41.4929; 

−113.6393, 41.4994; 

−113.7717, 41.5095; 

−113.6328, 41.5117; 

−113.7561, 41.5145; 

−113.6185, 41.5110; 

−113.6653, 41.5050; 

−113.6929, 41.5245; 

−113.7202, 41.5288; 

−113.6434, 41.5288; 

−113.7534, 41.5363

Doelling and others, 1980

South Mountain ID 50–45 Quartz diorite to 

granodiorite

−116.9025, 42.7738; 

−116.8866, 42.7176

Ekren and others, 1981
Description of Geology 15

Table 2. Names, ages, and modal compositions of igneous intrusions, and additional adjacent igneous intrusions in the study areas for 

the Sheldon-Hart Mountain National Wildlife Refuge Complex, Southeastern Oregon and North-Central Nevada, and Southern Idaho and 

Northern Nevada Sagebrush Focal Areas.—Continued

Intrusion name State Age (Ma) Modal composition Polygon centroid(s) References

Summit Creek NV Cretaceous Granodiorite −116.1054, 41.8596 du Bray, 2007

Winter Creek NV Cretaceous Granite −116.1096, 41.7869 du Bray, 2007

Boone Peak ID 87–60 Granodiorite −116.6964, 42.9061 Ekren and others, 1981

Duffer Peak NV 96 Granodiorite −118.6949, 41.6898; 

−118.6330, 41.6270; 

−118.7586, 41.6479

Smith, 1973

Mahogany Mountain NV 105 Granodiorite −118.6348, 41.7873 Colgan and others, 2010

Rattlesnake Spring NV 106 Quartz monzodiorite −118.6348, 41.7873 Colgan and others, 2010 

Thacker Canyon NV 108 Granodiorite −118.6348, 41.7873 Colgan and others, 2010

Lone Mountain NV 110 Quartz monzodiorite −118.6754, 41.8554 Colgan and others, 2010

Cold Spring NV 111 Quartz monzodiorite −118.6754, 41.8554 Colgan and others, 2010

New York Peak NV Cretaceous Quartz monzonite −118.7586, 41.6479 Smith, 1973

Emigrant Pass NV 162 Granite −118.6542, 41.8880 Colgan and others, 2010

Happy Creek NV 173 Monzogranitegranodiorite−118.4528, 41.4515 du Bray, 2007

Rocky Canyon Jackson NV TertiaryCretaceousGranodiorite −117.6358, 41.3537 du Bray, 2007

Strawberry Butte NV; OR 176 Quartz diorite −118.6593, 42.0152; 

−118.6632, 41.9989; 

−118.6459, 42.0287; 

−118.6290, 42.0482; 

−118.6896, 41.9822

Wolak, 1994

Baltazor NV 182 Unspecified −118.6433, 41.9279 Wolak, 1994

Theodore NV 184 Quartz diorite −118.6514, 41.6674; 

−118.6261, 41.6710; 

−118.6098, 41.6851;

−118.6895, 41.7356

Colgan and others, 2010

Cowden Creek NV; OR 188 Tonalite to quartz 

diorite

−118.7027, 41.9453 Wolak, 1994

Andorno NV TertiaryCretaceousGranodiorite −117.7465, 41.4296 du Bray, 2007

Austin Creek NV TertiaryCretaceousGranodiorite −117.7349, 41.4479 du Bray, 2007

Davey Town NV TertiaryCretaceousGranodiorite −117.9255, 41.3146 du Bray, 2007

Flynn NV TertiaryCretaceousGranodiorite −117.7613, 41.2670 du Bray, 2007

Porcupine Creek NV TertiaryCretaceousGranodiorite −117.7193, 41.3802 du Bray, 2007

Stonehouse NV TertiaryCretaceousGranodiorite −117.6827, 41.4131 du Bray, 2007

Dennis Hill UT Precambrian Metamorphosed 

quartz monzonite

−113.6138, 41.7968; 

−113.6354, 41.8075; 

−113.6203, 41.8059; 

−113.6733, 41.8107; 

−113.6250, 41.8185; 

−113.6335, 41.8330; 

−113.6139, 41.8364

Compton, 1972

Century Hollow UT Precambrian Metamorphosed 

quartz monzonite

−113.5294, 41.8563; 

−113.5137, 41.8596; 

−113.4905, 41.8685; 

−113.4482, 41.8798

Compton, 1972

Cedar Hills UT Precambrian Metamorphosed 

quartz monzonite

−113.7251, 41.9495; 

−113.7111, 41.9846

Compton, 1972
16 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Yellowstone Hot Spot; most of these younger calderas are now 

buried by younger mafic lava flows (Pierce and Morgan, 1992).

The exceptionally high-volume, bimodal volcanism 

associated with the Yellowstone Hot Spot inundated the land 

surface throughout the study areas, covering older rocks and—

potentially—mineral deposits. Most epithermal gold, silver, 

and mercury deposits throughout the study areas are closely 

associated with Miocene bimodal volcanism (Vikre, 1985b, 

2007; John, 2001; Saunders and others, 2008). An unusually 

wide variety of epithermal deposit types, including gold, silver, 

mercury, uranium, lithium, and gallium deposits, are spatially and 

temporally associated with peralkaline volcanism and formation of 

the McDermitt caldera at about 16.5 Ma (Rytuba and Glanzman, 

1979; Castor and Henry, 2000; Rytuba and others, 2003; Myers 

and Underhill, 2005; Carew, 2008).

Cenozoic Structure and Sedimentary Basins

The study areas are coincident with the northern edge of 

the Basin and Range Province, a region of fault-block mountain 

ranges formed during Cenozoic crustal extension. Most extensional 

faulting was accommodated by large half-graben or horst-andgraben normal faults with kilometers of offset, which formed 

the north-trending ranges and intermontane valleys that give the 

province its name. In northwestern Nevada, major fault-block 

ranges began forming about 12 to10 Ma (Colgan and others, 

2006a,b) and extensional faulting has continued to the present, 

becoming overall younger to the north in southeastern Oregon 

(for example, Scarberry and others, 2010). Extensional faulting 

in northeastern Nevada occurred locally as early as the Eocene 

(Rahl and others, 2002), but the main episode began about 17 to 

16 Ma and has continued to the present (Colgan and Henry, 2009). 

Middle Miocene sedimentary rocks deposited in extensional basins 

during this period are widely exposed throughout northeastern 

Nevada (fig. 3). The northern and western parts of the study area 

for the Southern Idaho and Northern Nevada Sagebrush Focal 

Area encompass the Owyhee Plateau and part of the Snake River 

Plain (fig. 3), which are north of the Basin and Range proper, and, 

although cut by many faults, were much less affected by Cenozoic 

extension.

Cenozoic extension influenced the formation and 

distribution of mineral deposits in three major ways: (1) pre- and 

synmineralization extensional faults and fracture systems provided 

conduits for fluids in the shallow crust, influencing the location of 

deposits formed during and after extension; (2) postmineralization 

extensional faults locally dismembered deposits, increasing or 

decreasing deposit depth and continuity; and (3) sedimentary rocks 

deposited in extensional basins potentially buried deposits formed 

during earlier periods of mineralization.

Valleys between major fault-bounded ranges are filled with 

fluvial and lacustrine deposits consisting of silt, sand, and gravel 

eroded from the bounding ranges and by volcanic tephra and 

lava flows. These valley-fill deposits range from tens of meters to 

kilometers in thickness (Blakely and Jachens, 1991). Most high, 

steep mountain ranges are flanked by fan deposits consisting 

of massive, poorly sorted, unconsolidated deposits with silt- to 

boulder-size clasts in a silty to sandy matrix. These deposits 

form aprons at the break in slope where drainages emerge from 

steeper upland areas. During the Miocene and Quaternary, some 

low-lying regions were inundated by large pluvial lakes in which 

fine-grained sediments were deposited (Wallace and others, 2004). 

Surficial deposits may host placer and diatomite deposits and may 

conceal deposits in the underlying bedrock. Epithermal gold and 

silver deposits are locally forming in unconsolidated surficial and 

basin-fill deposits in upflow zones of active thermal systems along 

basin-bounding faults in the study areas (Breit and others, 2011; 

Coolbaugh and others, 2011).

Locatable Minerals

Numerous locatable mineral commodities, including metallic 

and nonmetallic (also known as industrial) mineral commodities, 

occur in and near the four study areas. Many metallic commodities 

(for example, copper, silver, and lead) occur in several deposit 

types as determined by comparison to deposit type models (Day 

and others, 2016), and two or more metals (for example, gold 

and silver) commonly have been produced from one deposit. 

Commodities that (1) have been mined within the USGS study area 

boundary (fig. 1; table 3); (2) are known to exist within the USGS 

study area boundary from exposures in prospects and exploration 

drill holes; and (3) are suspected to exist within the USGS study 

area boundary on the basis of stratigraphy (including intrusions) 

and structures known to contain mined deposits, are included 

in table 1. Of the 46 locatable metallic and nonmetallic mineral 

commodities in table 1, and 14 commodities that are locatable or 

salable (depending largely on quality and value), 17 commodities 

were assessed for potential to occur in undiscovered deposits 

in each study area. Assessment of these 17 commodities was 

based primarily on (1) deposits (mines, resources, prospects, and 

occurrences) containing the assessed commodity or commodities 

(table 3); (2) geological, geochemical, alteration, geophysical, 

and other characteristics of the deposits and deposit types which 

included the assessed commodity or commodities (appendix 2; Day 

and others, 2016); (3) records of active and historical mining claims 

and surface-management plans provided by the BLM and USFS 

were also used in the assessment process; and (4) market analyses 

(appendix 5 and section I, Day and others, 2016). Locatable 

mineral commodities that were considered for assessment but were 

not assessed are briefly described in appendix 3.

Mineral potential assessment of the 17 commodities 

included (1) delineation of tracts that enclose rocks with 

favorable characteristics of deposit types (a) known to contain 

the assessed commodities, and (b) known to exist in the tract; 

(2) assignment of potential for undiscovered deposits in the 

tract; (3) assignment of relative certainty of mineral potential. 

Characteristics of deposits, including production, resources, 

stratigraphy and geochemistry of host rocks, structural control 

of deposits, and alteration mineral associations, are tabulated for 

each tract (appendix 2). Tracts are described and justified in the 

separate report sections on each study area. Maps showing tract 
Table 3. Mined deposits, with production, and resources of locatable mineral commodities within the USGS study areas. USGS, U.S. Geological Survey. 

[Some sources are in Fernette and others, 2016a. Nevada mining districts are from Tingley (1992). One flask of mercury = 76 pounds of mercury; one unit of tungsten = 20 pounds of tungsten trioxide (WO3) or 

15.86 pounds of tungsten; est., estimate; g/metric ton, grams per metric ton; ID, Idaho; kg, kilogram; lbs, pounds; M+I+I, measured plus indicated plus inferred; MST, million short tons; NV, Nevada; opt, troy ounce per short ton; OR, Oregon; oz, troy ounce; ppm, part per million; ST, short ton; U O3 8, triuranium octoxide; UT, Utah; WO3, tungsten trioxide; @, at; %, weight percent; $, U.S. dollars; M, million]

Mine/ Deposit name Assessment tract name Mining district County, state Commodity Production years Production Resource Notes; source

Sheldon-Hart Mountain National Wildlife Refuge Complex study area

Antelope Mine SHEP02, Sheldon 

West 

Lone Pine Washoe, NV Mercury 1939 5 flasks mercury — Ross (1941), Bailey and Phoenix 

(1944), Holmes (1965), Bonham and Papke (1969)

Gray Mine SHEP01, Coyote 

Hills

— Lake, OR Mercury 1941–43 7 flasks mercury — Fernette and others (2016a)

Farnham, Mogul, 

Rabbit Hole Mines

— — Washoe, NV; 

Lake, OR

Mercury 1919/1942 34 flasks mercury — Fernette and others (2016a)

Southeastern Oregon and North-Central Nevada study area

National Mine ONEP03, Buckskin National Humboldt, NV Gold and 

silver

1909–1929 175,502 oz gold; 457,190 

oz silver

— Vanderburg (1938)

Buckskin National 

Mine

ONEP03, Buckskin National Humboldt, NV Gold and 

silver

1908–1941 24,000 oz gold; 300,000 

oz silver

138,351 ST @ 0.363 

opt gold; 3.37 opt silver

Fernette and others (2016a), Vikre 

(1985b)

McCormick/Paradise 

Mine

ONEP03, Buckskin National Humboldt, NV Mercury 1930s 58 flasks mercury est. 2,000–3,000 

flasks

Vanderburg (1938), Roberts 

(1940)

Silver Butte claims ONEP04, Paradise 

Valley

Paradise Valley Humboldt, NV Silver and 

gold

1879–1935 est. $1.5–3M — Vanderburg (1938)

Cordero ONEP01, Cordero Opalite Humboldt, NV Gold and 

silver

— — — —

Cordero Mine ONEP01, Cordero Opalite Humboldt, NV Mercury 1941–43 105,636 flasks mercury — Yates (1942); Bailey and Phoenix 

(1944); Rytuba (1976); Speer (1977); NI 43-101 NV Cordero Gold Silver Project August 1, 2007 technical report; Fernette and others (2016a)

Cordero (McDermitt) 

Mine

ONEP01, Cordero Opalite Humboldt, NV Mercury 1975–1986 269,580 flasks mercury 1,070,000 ST @ 

7.25 lbs mercury/ST

Bretz Mine ONEP01, Cordero Opalite Malheur, OR Mercury 1931–1968 14,807 flasks mercury —

Opalite Mine ONEP01, Cordero Opalite Malheur, OR Mercury — 12,367 flasks mercury —

Ruja Mine ONEP01, Cordero Opalite Humbolt, NV Mercury — 6,000 flasks mercury —

Cordero (McDermitt) 

Mine

ONEP01, Cordero Opalite Humboldt, NV Gallium — — 21,562,700 million 

metric tons @ 46.5 ppm gallium (M+I+I)

Carew (2008)

Moonlight Mine ONVU01, Kings 

Valley 

Opalite Humboldt, NV Uranium — 600 kg (~1,320 lbs) 479,000 ST @ 

0.108% U O3 8

Castor and Henry (2000), Fernette 

and others (2016a)

Kings Valley South; 

Kings Valley North

ONVU01, Kings 

Valley 

Opalite Humboldt, NV Uranium — — 2,499,000 ST @ 

0.076% U O3 8

NI 43-101 NV Kings Valley 

Project December 20, 2007 technical report; Eggleston and others (2007)

Locatable Minerals 17
18 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah Mine/ Deposit name Assessment tract name Mining district County, state Commodity Production years Production Resource Notes; source Southeastern Oregon and North-Central Nevada study area—Continued Aurora ONVU01, Kings Valley Opalite Malheur, OR Uranium

—

— 76,390,184 ST @ 

248 ppm U

O3 8

https://aurorauraniumlimited.

wordpress.com/projects/, accessed January 14, 2016; Meyers and Underhill (2005)

Kings Valley Lithium ONVU01, Kings 

Valley 

Opalite Humboldt, NV Lithium

—

— 823 MST @ 0.30% 

lithium

Tetra Tech (2014), Eggleston 

(2008)

Southern Idaho and Northern Nevada study area

Jarbidge INEP04, Jarbidge Jarbidge Elko, NV Gold and 

silver

1910–1950 355,707 oz gold; 

1,666,222 oz silver

— LaPointe and others (1991)

 Alpha Mine

—

—

— Gold and 

silver

1923–26 $12,512

— Couch and Carpenter (1943)

 Bluster 

—

—

— Gold and 

silver

1916–1929 $74,374

— Couch and Carpenter (1943)

 Wildcat

—

—

— Barite 1955–58 2,727 ST

— LaPointe and others (1991)

 Coon Creek

—

—

— Tungsten 1943–1956 608 units WO3 — Stager and Tingley (1988)

Buckeye and Ohio INEP10, Good Hope Good Hope Elko, NV Gold and 

silver

1880–1882; 

1921

District: $100,000; 

~91,000 oz gold

— Emmons (1910), Knox (1970), 

LaPointe and others (1991)

—

—

—

— Antimony 1950 “several thousand 

pounds”

— Lawrence (1963), LaPointe and 

others (1991)

— INEP02, Cornucopia Cornucopia Elko, NV Silver and 

gold

Late 1800s 760,000 oz silver; 13,000 

oz gold

— Emmons (1910)

Diamond Jim, 

Rosebud, Gribble

INPR06, Island 

Mountain

Island Mountain Elko, NV Gold, 

silver, lead, zinc, copper, antimony, tungsten

1918–1982 District: 1,520 oz gold; 

120,671 oz silver; 822 ST lead; 42 ST zinc; 5 ST copper; 11 ST antimony; 15 units tungsten

26,300,000 ST @ 

0.019 opt gold

LaPointe and others (1991); Fernette, Bellora, and others (2016)

Doby George INCT06, Doby 

George 1

Island Mountain Elko, NV Gold

—

— 27,100,000 ST @ 

0.028 opt gold

Davis and others (2006); NV NI 

43-101 Doby George-Wood Gulch-IL Ranch Properties April 24, 2008 technical report

Big Springs INCT04, Big 

Springs 1

Independence 

Mountains

Elko, NV Gold 1987–1993 386,000 oz gold 14.8 million metric 

tons @ 2 g/metric ton gold

Anova Metals Limited (2016)

Table 3. Mined deposits, with production, and resources of locatable mineral commodities within the USGS study areas. USGS, U.S. Geological Survey.—Continued 
Mine/ Deposit name Assessment tract name Mining district County, state Commodity Production years Production Resource Notes; source

Southern Idaho and Northern Nevada study area—Continued

Bull Run, Lucky Girl — Edgemont Elko, NV Gold, 

silver, lead, zinc, copper, tungsten

1902–1971 District: 39,121 oz gold; 

90,649 oz silver; 100 ST lead; 2 ST zinc; 1 ST copper; 3 units tungsten

— LaPointe and others (1991)

White Rock INEP06, Angel Wing — Elko, NV; Box 

Elder, UT

Gold 2009 — 9,000,000 ST @ 

0.018 opt gold; ~150,000 oz gold

Goodall (2003), Kehmeier (2009)

Gravel Creek INEP03, Wood 

Gulch

— Elko, NV Gold and 

silver

— — 16,940,000 ST @ 

0.08 opt gold; 1.2 opt silver

Inventory; Fernette and others 

(2016a)

Wood Gulch INEP03, Wood 

Gulch

— Elko, NV Gold 1988–1990 34,782 oz gold Est. 780,000 ST @ 

0.12 opt gold

NV NI 43-101 Doby GeorgeWood Gulch-IL Ranch 

Properties April 24, 2008 technical report

Blue Hill Creek INE07, Oakley — Cassia, ID Gold — — 14,400,000 ST @ 

0.016 opt gold

Fernette and others (2016a)

Cleveland, Delano INPR10, Delano Delano — Gold, 

silver, lead, zinc, copper

1918–1980 District: 333 oz gold; 

1,499,973 oz silver; 11,069 ST lead; 693 ST zinc; 84 ST copper; 384 units tungsten

— LaPointe and others (1991)

Indian Springs INPR10, Delano Delano Elko, NV Tungsten — — 18,900,000 ST @ 

0.17% WO3

Stager and Tingley (1988), 

LaPointe and others (1991)

Blue Ribbon-Boyce — Aurum Elko, NV Antimony 1940 7 ST antimony — Lawrence (1963)

Rio Tinto, Mountain 

Laurel, Silver King

INPR02, Mountain 

City; INMS02, Rio Tinto 1

Mountain City Elko, NV Copper, 

gold, silver, lead

1869–1982 District: 101,984 ST 

copper; 20,557 oz gold; 559,561 oz silver; 54 ST lead; <1 ST zinc

— LaPointe and others (1991)

Race Track, Rim 

Rock, South ForkPixley

INHU01, Racetrack Mountain City — Uranium 1950s–1960s 20,876 lbs U O3 8 1,100,000 lbs U O3 8 Drilled resource 1967–1983; 

Bayswater Uranium Corporation (2007); Proffitt and others (1982)

Blue Jacket INPR04, Blue Jacket Aura Elko, NV Gold, 

silver, copper, lead, zinc

— — 2 MST @ 0.01 opt 

gold; 2.2 opt silver; 0.25% copper; 2% lead; 1.8% zinc

Long and others (1998)

Locatable Minerals 19

Table 3. Mined deposits, with production, and resources of locatable mineral commodities within the USGS study areas. USGS, U.S. Geological Survey.—Continued 
20 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah Mine/ Deposit name Assessment tract name Mining district County, state Commodity Production years Production Resource Notes; source Southern Idaho and Northern Nevada study area—Continued Contact INPR09, Contact Contact Elko, NV Copper, gold, silver, lead, tungsten 1908–1965 District: 2,876 ST copper; 1,222 oz gold; 126,901 oz silver; 180 ST lead; 9 ST zinc; 117 units WO3 473,000,000 ST @ 0.19% copper LaPointe and others (1991), Fernette and others (2016a) Consolation-Boies, Big Ledge, Hunch, Jungle A, Jungle, Little Dry INBB02, Snake Mountains 1 Snake Mountains Elko, NV Barite 1974–1985 District: 1,008,964 ST barite

— LaPointe and others (1991)

Batholith

— Charleston Elko, NV Tungsten 1954–56 452 units WO3 — Stager and Tingley (1988)

Prunty

—

—

— Gold, 

silver, copper, lead, antimony, tungsten

— District: 2,177 oz gold; 

2,861 oz silver; 4 ST copper; 7 ST lead; <1 ST zinc; 16 ST antimony

— LaPointe and others (1991)

Garnet

— Alder Elko, NV Tungsten

—

— 748,000 ST @ 

0.43% WO3

LaPointe and others (1991)

Ashbrook INPR15, Ashbrook Ashbrook Box Elder, UT

—

— District: 180,000 ST ore; 

3,440,000 oz silver

— Gloyn and Krahulec (2006)

Table 3. Mined deposits, with production, and resources of locatable mineral commodities within the USGS study areas. USGS, U.S. Geological Survey.—Continued 
Leasable Minerals 21

outlines and selected tract-defining characteristics accompany 

tract descriptions (San Juan and others, 2016).

Leasable Minerals

Leasable solid and fluid mineral commodities covered 

in this report are oil and gas, coal, potash, phosphate, borates, 

and geothermal (table 1). None of these commodities has been 

produced within the USGS study area boundaries. No exploration 

and leasing activity for borates has occurred and there is 

apparently no permissive stratigraphy for borates in the four study 

areas. Exploration and leasing activity, and permissive stratigraphy 

for oil and gas, coal, potash, phosphate, and geothermal are 

briefly summarized below. Two unmined coal fields and favorable 

stratigraphy for phosphate deposits occur within the USGS 

study area boundary of the Southern Idaho and Northern Nevada 

Sagebrush Focal Area. The coal fields and favorable phosphate 

stratigraphy, which have low production potential because of low 

quality (value) and (or) quantity, are described in the report section 

“Mineral-Resource Potential of the Study Area for the Southern 

Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, 

and Utah.”

Oil and Gas 

The four study areas lie within the Eastern Great Basin, 

Idaho-Snake River Downwarp, and Western Great Basin oil and 

gas provinces. According to IHS Enerdeq well data (IHS Energy 

Group, 2016), there has been no significant oil or gas production 

within the study areas (fig. 4; appendix 4). Some oil has been 

produced in Elko County, Nevada, about 15 mi south of the study 

area for the Southern Idaho and Northern Nevada Sagebrush Focal 

Area, Nevada, Idaho, and Utah, in the Toano Draw Field and the 

Deadman Creek Field. About 367 barrels were produced from 

the Miocene Humboldt Formation in the 1990s before the well 

became inactive (LaPointe and others, 2007). Many dry wells are 

present in the study areas.

The four study areas have been assessed for potential 

hydrocarbon resources. Two plays (Miocene Lacustrine, and 

older Tertiary [nonquantitative]) from the 1995 assessment of the 

Idaho-Snake River Downwarp Province include some northeast 

PLSS townships within study areas. Some 1995 plays from the 

western part of the Great Basin Province include some western 

PLSS townships within study areas. These plays include the 

Eastern Oregon Neogene Basins, Cretaceous Source Rocks 

of Northwestern Nevada, and the Neogene Source Rocks of 

Northwestern Nevada and Eastern California; however, these 

are hypothetical plays and were not quantitatively assessed. 

There are also assessment units in the Eastern Great Basin 

Province that overlap some study areas. Overall, there are seven 

assessment units or plays in three oil and gas provinces included 

in parts of the four study areas. Within the Idaho-Snake River 

Downwarp Province, there are assessed mean potential resources 

of 0.9 million barrels of oil (MMBO), and 11.2 billion cubic 

feet (BCF) of gas (Peterson, 1995). Within the Eastern Great 

Basin Province, the USGS assessed potential mean resources of 

almost 1,300 MMBO, 1,302 BCF of gas, and 60 million barrels 

of natural gas liquids (NGLs) (U.S. Geological Survey Eastern 

Great Basin Assessment Team, 2007).

Of the 565 townships in the four study areas, 208 are not 

associated with an oil and gas assessment unit. Although some 

potential oil and gas resources have been accessed in the area 

and near some of the study areas, there has been no significant 

hydrocarbon production within the study areas and overall 

potential appears to be low to moderate considering the presence 

of several dry wells within the study areas. 

Coal

Two low-quality lignite coal fields are in the study area 

for the Southern Idaho and Northern Nevada Sagebrush Focal 

Area (fig. 5). A coal field is a discrete area underlain by strata 

containing one or more coal beds (Wood and others, 1983). 

In the context for this report, a coal field is considered an area 

where coal is or has been produced or has significant potential 

to be produced economically, and a coal region is considered 

as an area underlain by coal-bearing formations. These two 

low-quality lignite coal fields are described in the report section 

“Mineral-Resource Potential of the Study Area for the Southern 

Idaho and Northern Nevada Sagebrush Focal Area, Nevada, 

Idaho, and Utah; Coal.”

No coal resources and no coal-bearing formations occur 

in the study area for the Sheldon-Hart Mountain National 

Wildlife Refuge Complex Sagebrush Focal Area. The USGS 

report of coal fields in the conterminous United States (East, 

2013) shows that this study area is not within any known 

coal region and no coal fields or regions are within the 25-km 

buffer zone (Smith and Roe, 2015). Rocks and strata exposed 

at the surface within the proposed withdrawal area include 

Quaternary alluvium, and Tertiary, Miocene, and Pliocene 

basalts, andesites, and volcaniclastic strata.

Potash

 No potash production has occurred, and no potash deposits 

are in the four study areas. Closed and expired potash leases are 

in the study area for the Southeastern Oregon and North-Central 

Nevada Sagebrush Focal Area (fig. 6; table1). Favorable geologic 

environments in and near the four study areas, and the potash 

leases, are described in the report section “Mineral-Resource 

Potential of the Study Area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Nevada and Oregon; 

Occurrence of Leasable Minerals; Potash.”
22 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah Goose

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Base modified from U.S. Geological Survey DEM data, 2016.Roads and political data copyright © 2014 Esri and its licensors.Boundary data from San Juan and others (2016).USA Contiguous Albers Equal Area Conic Projection.Central meridian, 118° W., latitude of origin, 37.5° N.North American Datum of 1983.

0 25 50 75 100 MILES0 25 50 75 100 KILOMETERS

Southeastern Oregon and North-Central Nevada

Study Area

Sheldon-Hart Mountain National Wildlife Refuge Complex

Study Area

Southern Idaho and Northern Nevada

Study Area

Nevada additions

Base data

USGS study area boundary

USGS study area boundary(North-Central Idaho Study Area)

Proposed withdrawal areas

Proposed withdrawal additionsState boundariesCounty boundaries

Oil and gas exploration (dry)

EXPLANATION

Oil and gas sections

BLM—Leasable commodities, energy

Oil and gas exploration

Figure 4. Map showing Public Land Survey System (PLSS) sections that contain Bureau of Land Management (BLM) oil and gas leases and oil and gas exploration (dry) in the four USGS study areas (Dicken and San Juan, 2016; IHS Energy Group, 2016; Gunther and others 2016a,b). USGS, U.S. Geological Survey. 
Leasable Minerals 23

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Map

area Study areas

IDAHO

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OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

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North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Nevada additions

Southeastern Oregon and North-Central Nevada

Study Area Southern Idaho and Northern Nevada

Study Area

Proposed withdrawal additions

State boundaries

County boundaries

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

EXPLANATION

Goose Creek

Grouse Creek

Coal fields in the Southern Idaho and Northern Nevada Sagebrush Focal Area

Figure 5. Map showing coal fields in the study area for Southern Idaho and Northern Nevada Sagebrush Focal Area (East, 2013). The 

Goose Creek and Grouse Creek coals are low-quality lignite that has not been mined. USGS, U.S. Geological Survey.
24 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

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Nevada additions

Southeastern Oregon and North-Central Nevada

Study Area

Southern Idaho and Northern Nevada

Study Area

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

BLM—Leasable commodities (potash leases), non energy: commodity;

case disposition 

EXPLANATION

Potash, potassium; closed, rejected

Base data

USGS study area boundary

Proposed withdrawal areas

Proposed withdrawal additions

State boundaries

County boundaries

Figure 6. Map showing Bureau of Land Management (BLM) potash leases in the study area for the Southeast Oregon and NorthCentral Nevada Sagebrush Focal Area. No potash is currently being mined within the proposed withdrawal areas and U.S. Geological 

Survey (USGS) study area boundary (Dicken and San Juan, 2016).
Salable Minerals 25

Phosphate 

No phosphate production has occurred, and there are 

no phosphate deposits in the four study areas. However, 

mined phosphate deposits in southern Idaho occur in Permian 

Phosphoria Formation strata, which extend into the study 

area for the Southern Idaho and Northern Nevada Sagebrush 

Focal Area. Phosphate also occurs in the Mississippian 

Deseret Limestone, Woodman Formation, and Chainman 

Shale in the study area (fig. 7). Phosphate deposits in southern 

Idaho constitute a major source of phosphorous products and 

vanadium, a minor source of uranium, and a potential source 

of rare earth elements. The depositional environment of 

phosphate, phosphate resources, and phosphate occurrences 

are described in the report section “Mineral-Resource Potential 

of the Study Area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area, Nevada, Idaho, and Utah; Phosphate.”

Geothermal

The Great Basin is within the Basin and Range Province, 

which is characterized by active crustal extension and elevated 

heat flow relative to the rest of the continental craton (Sass 

and others, 2005). It represents one of the largest geothermal 

provinces in the world; more than 20 power plants with 

about 550 megawatts (mW) of installed capacity are in the 

Great Basin. Based on a 2008 assessment (Williams and 

others, 2008) geothermal systems in the Great Basin have the 

potential to produce about 30,000 mW. The high potential 

of the province is attributed to crustal thinning from high 

extensional strain rates (Blewitt and others, 2005; Faulds and 

others, 2012) that cause elevated crustal temperature gradients 

in much of the Great Basin. Many geothermal systems have 

little or no surface manifestation (Coolbaugh and others, 2006; 

Faulds and Hinz, 2015), and additional power generation 

will largely be derived from concealed and enhanced 

geothermal systems (Williams and others, 2008, 2011). The 

Snake River Plain along the northern margin of the Great 

Basin is also characterized by high heat flow and represents 

a potential geothermal resource area (Brott and others, 1981; 

Fleischmann, 2006; Shervais and others, 2016; Welhan, 2016).

Geothermal systems in the Great Basin are either 

magmatic or amagmatic. Magmatic systems derive heat from 

mid- to shallow-crustal magmas and are typically larger 

and higher temperature than amagmatic systems, which 

derive heat from deep circulation of water in extensional 

fault regimes (Duffield and Sass, 2003; Williams and others, 

2008). High-temperature (more than 150 degrees Celsius, °C) 

magmatic systems generate electrical power more efficiently 

than lower temperature amagmatic systems. Most magmatic 

systems are concentrated along the western margin of the Great 

Basin and in the Snake River Plain, whereas most amagmatic 

systems occur in the western interior of the Great Basin. 

Numerous low- and moderate- to high-temperature 

systems (90 °C to more than 150 °C) are within and adjacent 

to the four study areas (fig. 8). Although no geothermal power 

plants are in the study areas, four producing sites in Oregon, 

Idaho, and Nevada are within 100 km of the USGS study area 

boundary, and numerous are in development stages (National 

Renewable Energy Laboratory, 2016). Areas with elevated 

geothermal potential include parts of the proposed withdrawal 

areas based on geothermal resource favorability of both 

identified and undiscovered systems (Williams and others, 

2008).

Salable Minerals

Salable mineral commodities, or mineral materials, 

discussed in this report are common varieties (low unit value) 

of sand and gravel, aggregate, crushed rock, dimension stone, 

decorative stone, petrified wood, cinders, clay, and pumice. Some 

mineral commodities can be locatable or salable, depending 

on value or physical properties such as hardness, color, and 

appearance (table 1; appendix 3). Salable mineral commodities 

are used for road and building construction, agriculture, and 

landscaping. There are 670 authorizations (contracts; 110 

authorized, 545 closed, 7 pending, 6 expired, 1 rejected, and 1 

withdrawn) for salable mineral commodities within the USGS 

study area boundary for the four study areas. The number 

of authorizations and maps of salable mineral commodity 

authorization sites within each study area are included in the 

report sections on each study area. 

Most authorizations in the four study areas are for 

sand and gravel produced from numerous sites. Other 

authorizations are for stone (including specialty, weathered, 

riprap, crushed, and dimension stone) gemstones, common 

clay, and pumice (volcanic cinder). Some gemstones, 

including sunstones mined in the study area for the SheldonHart Mountain National Wildlife Refuge Complex Sagebrush 

Focal Area, have high unit value. High-value gemstones are 

locatable mineral commodities, and deposits of them are 

covered by lode mining claims. No authorizations for petrified 

wood exist in the four study areas.
26 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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area Study areas

IDAHO

MONTANA

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WYOMING

NEVADA UTAH

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Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Southern Idaho and Northern Nevada

Study Area

Southeastern Oregon and North-Central Nevada

Study Area

Nevada additions

Nevada additions

Proposed withdrawal additions

State boundaries

County boundaries

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

EXPLANATION

Pennsylvanian-Permian phosphorite, shale, chert, mudstone, 

 and limestone

Phosphate occurrences

Figure 7. Map showing phosphate-bearing rocks in the study area for the Southern Idaho and Northern Nevada Sagebrush Focal 

Area. Most phosphate in and adjacent to the Sagebrush Focal Area occurs in beds (as phosphorite) within sedimentary rock of the 

Pennsylvanian-Permian Phosphoria Formation (Compiled from Hintze and others, 2000; Crafford, 2007; Lewis and others, 2012). USGS, 

U.S. Geological Survey.
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0 25 50 75 100 MILES0 25 50 75 100 KILOMETERS

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Base data

USGS study area boundary

USGS study area boundary(North-Central Idaho Study Area)

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EXPLANATION

Geothermal; authorized

Geothermal; closed

BLM—Leasable commodities, energy: commodity; case disposition Hydrothermal favorability

HighLow

Geothermal sites

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Figure 8. Map showing Bureau of Land Management (BLM) geothermal leases, favorability, sites, and systems in the four USGS study areas (Dicken and San Juan, 2016; Williams and others, 2008a,b). USGS, U.S. Geological Survey.

Salable Minerals 27

Mineral-Resource Potential of the Study Area for the 

Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area, Nevada and Oregon

Introduction

The study area for the Sheldon-Hart Mountain National 

Wildlife Refuge Complex Sagebrush Focal Area spans the border 

of Oregon and Nevada and includes parts of Washoe County, 

Nevada, and Harney and Lake Counties, Oregon (fig. 9). This report 

section describes the mineral potential of the proposed withdrawal 

area within the study area for the Sheldon-Hart Mountain National 

Wildlife Refuge Complex Sagebrush Focal Area. This study area 

includes parts of the proposed withdrawal area described in the 

“Introduction” section of this report. The proposed withdrawal area 

within this study area encompasses 943,866 acres (~3,820 km2

; 

1,475 mi2) which are managed by the BLM.

Description of Geology

Paleozoic, Mesozoic, Tertiary, and Quaternary rocks are 

exposed within the study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area, Nevada 

and Oregon, and the USGS study area boundary (fig. 10). Paleozoic 

and Mesozoic rocks include volcanic and sedimentary rocks of the 

Black Rock (Devonian to Triassic) and Pueblo (Jurassic) terranes, 

and granitic rocks (Jurassic and Cretaceous). Tertiary strata are 

predominantly volcanic lava flows and tuffs, and sedimentary 

rocks (Miocene and Pliocene). Quaternary strata include volcanic 

rocks and surficial deposits. The terranes were juxtaposed by 

compressional tectonism during the Mesozoic. Terranes and 

Tertiary volcanic strata have been laterally displaced by late Tertiary 

extensional tectonism which produced the modern landforms of 

alternating, north-south-oriented mountain ranges separated by 

broad, relatively flat valleys (Basin and Range topography).

More complete descriptions of these strata, and their 

tectonic evolution, are in report section “Introduction; 

Description of Geology.”

Mineral-Resource Potential

Mineral Deposit Types

Characteristics of metallic and nonmetallic locatable 

mineral deposits, prospects, and host rocks in the study area for 

the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area, Nevada and Oregon (appendix 2), are 

compatible with classification of these deposits as epithermal gold, 

silver, and mercury deposits, gemstone deposits, and lacustrine 

diatomite deposits (Day and others, 2016). 

Epithermal gold, silver, and mercury deposits are 

shallowly formed vein, stockwork, disseminated, and 

replacement deposits that are mined primarily for gold 

and silver. Hot-spring-type mercury deposits are often the 

near-surface expression of gold and silver deposits that 

occur at deeper levels below mercury-enriched sinter and 

volcaniclastic strata. Epithermal gold, silver, and mercury 

deposits in the western United States occur largely in EoceneMiocene volcanic fields and have been mined primarily for 

gold and silver, and lesser mercury (on the basis of mass and 

value).

There are few deposit type models for gemstone deposits 

because of the small deposit size, small market, and limited 

number of most gemstone deposits, and because demand for 

most is based entirely on appearance. The gemstone deposits 

evaluated in this study area, sunstones, are a gem-quality 

form of copper-included feldspar which occur locally in 

weathered Tertiary basalt flows in several areas of Oregon.

Lacustrine diatomite deposits consist of chalklike, 

earthy siliceous sedimentary strata composed of diatoms. 

In volcanic terranes, diatomaceous lake sediments typically 

occur within sequences of volcanic and sedimentary rocks. 

Lacustrine diatomite deposits in the western United States 

occur primarily in high-silica sequences of middle Miocene 

flows and tuffs.

Geology and Occurrence of Mineral Deposit 

Types

The study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area 

is entirely underlain by Tertiary and Quaternary volcanic 

and sedimentary rocks (fig. 10). Epithermal gold and silver 

deposits in Tertiary volcanic rocks occur in the Coyote Hills, 

Lake County, Oregon; and epithermal mercury deposits 

occur in Tertiary volcanic rocks in the Antelope district, 

Washoe County, Nevada. Gemstone deposits occur in Tertiary 

basalts in Lake County, Oregon. Lacustrine diatomite occurs 

in Tertiary volcanic flows, tuffs, and associated epiclastic 

sedimentary strata.
30 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

MODOC

COUNTY

HUMBOLDT

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WASHOE

COUNTY

HARNEY

COUNTY

LAKE

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CALIFORNIA NEVADA

OREGON

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WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

EXPLANATION

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Figure 9. Map showing proposed withdrawal areas that comprise the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area, Nevada and Oregon, and boundary of the U.S. Geological Survey (USGS) study area. The study area boundary 

corresponds to townships that enclose the withdrawal areas.
Mineral-Resource Potential 31

Base modified from U.S. Geological Survey DEM data, 2016.

Political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

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120°00 118°30'

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Black Rock terrane (Triassic to Devonian)

Mesozoic granitic rocks (Cretaceous and Jurassic)

Pueblo terrane (Jurassic) Surfical deposits (Quaternary)

Volcanic rocks (Quaternary)

Intrusive rocks (Tertiary)

Rhyolite tuffs and lava flows (Pliocene and Miocene)

Sedimentary rocks (Pliocene and Miocene)

Mafic to intermediate lava flows (Pliocene and Miocene)

Volcanic and sedimentary rocks (Miocene to Eocene)

EXPLANATION

Generalized lithologic units (geologic age)

Base data

USGS study area boundary

State boundaries

Water body

Map

area

Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Figure 10. Simplified geologic map of the study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal 

Area, Nevada and Oregon. Synthesized from Jennings and others (1977), Walker and MacLeod (1991), Saucedo and others (2000), Miller 

and others (2002), and Crafford (2007). 
32 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Exploration and Mining Activity for Locatable 

Minerals

Metallic and nonmetallic locatable mineral commodities 

that have been mined and explored for in the study area for the 

Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area include gold, silver, mercury, and 

gemstones. Numerous lode and placer claims have been staked in 

the study area (fig. 11; tables 4, 5), and several plans of operations 

and notices covering mineral exploration have been approved or 

are pending (fig. 11; tables 6, 7). In addition, numerous claims 

were staked and filed in the study area from 1976 to 2007 (Causey, 

2007, 2011; fig. 12). 

Within the study area, two mercury deposit were mined 

for mercury with recorded production of 12 flasks (one flask of 

mercury is equal to 76 pounds of mercury) (table 8; Bailey and 

Phoenix, 1944; Fernette and others, 2016a). Gemstones have 

been mined from several sites in the study area, three of which are 

active mines, but production has not been published. Numerous 

mines and prospects excavated for mercury, gold, and silver 

deposits occur in several parts of the study area (fig. 13).

A qualitative estimate of past mining activity for 

locatable metallic (and nonmetallic) mineral commodities 

was made by counting mining-related symbols on USGS 

topographic maps that cover the study area (Fernette and 

others, 2016b). There are 156 mine features shown on USGS 

7.5-minute topographic maps, 8 of which are adits or mine 

shafts and 80 are prospect pits. These symbols are commonly 

associated with mining and exploration of locatable minerals 

and provide a broad indication of the extent of past mining 

activity in the area. Other mine symbols include borrow pits, 

gravel pits, and cinder pits, which are commonly associated 

with production of salable minerals.

A second qualitative estimate of past mining activity 

was made by extracting mines and deposits with the statuses 

“producer” and “past producer” from the USGS Mineral 

Resources Data System (MRDS). The MRDS database 

contains 32 records of “producer” and (or) “past producer,” 

3 of which were mined for mercury, 5 for gemstones, 1 for 

nonmetallic (industrial) minerals (perlite), and 23 for stone, 

sand, and gravel (U.S. Geological Survey, 2005). However, 

some MRDS records may be duplicates. The MRDS database 

contains no production data for these mines and deposits.

Table 4. Type, number, and status of mining claims, leases for leasable mineral commodities (coal, geothermal, non-energy solid 

mineral, oil and gas leases), mineral material sales sites for salable mineral commodities, and surface-management plans in the 

proposed withdrawal area within the study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal 

Area, Nevada and Oregon (Dicken and San Juan, 2016).

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey System (PLSS) section that includes a proposed withdrawal area]

Type Mineral 

type

Number 

of unique 

cases

Active Authorized Pending Closed Cancelled Expired Rejected Withdrawn

Mining claims Locatable 830 101 — — 729 — — — —

Coal leases Leasable — — — — — — — — —

Geothermal leases Leasable 69 — — — 69 — — — —

Non-energy solid 

mineral leases

Leasable — — — — — — — — —

Oil and gas leases Leasable 195 — — — 195 — — — —

Mineral materials 

sales sites

Salable 29 — 10 1 18 — — — —

Surface-management 

plans

— 44 — 5 3 35 — — — 1
Mineral-Resource Potential 33

Table 5. Summary of active and closed mining claims for locatable minerals in Public Land Survey System (PLSS) sections that include 

the proposed withdrawal area within the study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal 

Area, Nevada and Oregon.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey System (PLSS) section that includes a proposed withdrawal area]

Area Active lode 

claims

Closed lode 

claims

Active 

placer 

claims

Closed 

placer 

claims

Active 

millsites

Closed

millsites

Sections containing proposed withdrawal area 101 685 0 44 0 0

Table 6. Status and number of 43 Code of Federal Regulations (CFR) 3809 notices and plans of operations for locatable minerals in the 

proposed withdrawal area within the study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal Area, 

Nevada and Oregon.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey System (PLSS) section that includes a proposed withdrawal area]

Authorization type Number of 

unique cases Active Authorized Pending Closed Cancelled Expired Rejected Withdrawn

Plans of operations 5 — 1 2 1 — — — 1

Notice 39 — 4 1 34 — — — —

Table 7. Active 43 Code of Federal Regulations (CFR) 3809 notices and plans of operations summarized by locatable commodity in the 

proposed withdrawal area within the study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal 

Area, Nevada and Oregon.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey System (PLSS) section that includes a proposed withdrawal area]

Commodity Active notices Active plans of operations

Gemstone, semiprecious silica 4 3

Gold, lode 1 0

Table 8. Mined deposits with production in the study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush 

Focal Area, Nevada and Oregon.

[Sources from Fernette and others, 2016a,b. Mining districts are from Tingley (1992); One flask of mercury = 76 pounds of mercury; OR, Oregon; NV, Nevada]

Mine/ Deposit name Assessment tract Mining 

district County, state Commodity Production years

Production Resource Notes; source

Antelope Mine SHEP02, Sheldon West Lone Pine Washoe, NV Mercury 1939 5 flasks 

mercury

— Ross (1941), Bailey 

and Phoenix (1944), 

Holmes (1965), 

Bonham and Papke 

(1969)

Gray Mine SHEP01, Coyote Hills — Lake, OR Mercury 1941–1943 7 flasks 

mercury

— Brooks (1965), Fernette 

and others (2016a)

Farnham, Mogul, 

Rabbit Hole Mines

— — Washoe, NV 

Lake, OR

Mercury 1919/1942 34 flasks 

mercury

— Fernette and others 

(2016a)
34 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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WYOMING

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WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

EXPLANATION

BLM—Locatable commodities: commodity; case disposition; case type

Gold, gold lode; authorized, pending; surface-management notice

Gold, gold lode, gold placer, copper; closed, expired,

 cancelled; surface-management notice

Gemstone (sunstone; lode claims)

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Figure 11. Map showing active and closed Bureau of Land Management (BLM) surface-management plans of operations and notices 

for locatable mineral commodities in the study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal 

Area, Nevada and Oregon (Dicken and San Juan, 2016). USGS, U.S. Geological Survey.
Mineral-Resource Potential 35

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WASHOE

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HARNEY

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LAKE

COUNTY

CALIFORNIA NEVADA

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area

Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

EXPLANATION

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Number of active lode claims per section

1–8

9 –21

22–36

Sections with only closed claims (including placer)

Sections with one or more active placer claims outlined in white

A

Figure 12. Maps showing mining claims by Public Land Survey System (PLSS) section in the study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon. A, Number of active lode claims and placer claims per 

section (Dicken and San Juan, 2016). B, Thirty-five year averages of the number of active lode claims by section for mining claims 

located between 1976 and 2010 (Causey, 2007, 2011).
36 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Goose

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COUNTY HUMBOLDT

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CALIFORNIA NEVADA

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IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

EXPLANATION

4.48–26.86

1.72–4.47

0.44–1.71

0.12–0.43

0.04–0.11

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

B

Thirty-five year average of the number of active lode claims by section

Figure 12. Maps showing mining claims by Public Land Survey System (PLSS) section in the study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon. A, Number of active lode claims and placer claims per 

section (Dicken and San Juan, 2016). B, Thirty-five year averages of the number of active lode claims by section for mining claims 

located between 1976 and 2010 (Causey, 2007, 2011).—Continued
Mineral-Resource Potential 37

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

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COUNTY HUMBOLDT

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Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

EXPLANATION

Mine status

Active

Inactive

Uncertain

Mining districts

!(

!(

!(

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Figure 13. Map showing mining districts and mine status in or near the study area for the Sheldon-Hart Mountain National Wildlife 

Refuge Complex Sagebrush Focal Area, Nevada and Oregon (Fernette and others, 2016a). USGS, U.S. Geological Survey.
38 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Mineral Potential of Locatable Minerals

Potential for undiscovered deposits of locatable mineral 

commodities (metallic locatable minerals and nonmetallic 

locatable minerals) within this study area was evaluated for 

the locatable commodities gold, silver, mercury, gemstones, 

and diatomite. These mineral commodities were selected for 

evaluation on the basis of deposits in this study area with past 

and present production, prospects, hydrothermal alteration, 

stratigraphy of host rocks, and other geological characteristics 

of deposit types for these commodities (Day and others, 2016; 

appendix 2; table 1). Records of active and historic mining claims 

and surface-management plans provided by the BLM and USFS 

were also used in the assessment process. Mineral-resource 

potential is represented by rated tracts; these tracts consist of areas 

favorable for undiscovered deposits of one or more commodities 

that are enclosed by a tract boundary and are assigned qualitative 

potential (high, moderate, or low/permissive) and a level of 

potential certainty. The tract boundaries include a buffer of 

variable dimension that reflects spatial uncertainty of one or more 

of the characteristics used to delineate the tract. The qualitative 

mineral potential ratings are derived from a classification 

matrix that merges mineral potential and level of certainty. The 

methodology used to assess locatable mineral-resource potential 

and levels of certainty are reviewed in Day and others (2016) and 

are summarized in appendix 1.

Delineation and rating of tracts are based entirely on 

publications from libraries and Web sites; technical reports, 

documents, and maps from active Web sites and Web sites that 

are no longer maintained; and documents provided by companies 

with mineral rights on lands included in the proposed withdrawal 

area. Technical reports, documents, and maps that are not available 

on Web sites, and those provided by companies, can be accessed 

in a database (Fernette and others, 2016a) that includes mineral 

deposits with production and resources, and mineral exploration 

sites within the study areas. All publications, technical reports, 

documents, and maps used to delineate and rate tracts are cited in 

tract descriptions, in tables of tract characteristics, and in tables of 

deposit production, resources, and mineral exploration sites. We 

did not perform field examinations, mapping, or analyses of the 

tracts, deposits, and resources described in this report section.

Mineral Potential Tracts for Epithermal Gold, 

Silver, and Mercury Deposits

Two mineral potential tracts for epithermal gold, silver, and 

mercury deposits were delineated and rated: tract SHEP01, Coyote 

Hills, which has moderate potential for epithermal gold, silver, 

and mercury deposits, and tract SHEP02, Sheldon West, which 

has moderate potential for epithermal mercury deposits. These 

commodities occur in one well-defined deposit type, epithermal 

gold, silver, and mercury deposits (fig. 14A).

Tract SHEP01, Coyote Hills—A moderate potential 

(M), with certainty level C, for epithermal gold, silver, and 

mercury deposits is assigned to an area enclosing numerous 

prospects in the Coyote Hills, Lake County, Oregon (tract 

SHEP01, Coyote Hills; fig. 14A; appendix 2). The area 

consists of an Oligocene(?) rhyolite-dacite lava dome complex 

emplaced into Eocene to Oligocene andesite and basalt lava 

flows and breccias and volcaniclastic sedimentary rocks 

(Thomas, 1981; Walker and MacLeod, 1991). Faulting and 

hydrothermal activity shortly followed emplacement of the 

dome complex, which resulted in prominent areas of silicic 

and argillic alteration and low-grade precious and base metal 

mineralization. A minor production of mercury (less than 

10 flasks) during World War II was derived from cinnabar 

occurrences within the tract (Brooks, 1965; table 8).

The tract was delineated using a 3-km buffer around 

prospects in the Mineral Resources Data System and Mineral 

Information Layer for Oregon (MRDS, U.S. Geological Survey, 

2005; MILO-Mineral Information Layer for Oregon, 2016) 

and encompasses the entire silicic dome complex as mapped 

by Thomas (1981). It is characterized by scattered areas of 

advanced argillic, kaolinitic argillic, sericitic, and iron-oxide 

alteration interpreted from ASTER (Advanced Spaceborne 

Thermal Emission and Reflection Radiometer) remote-sensing 

spectra (Rockwell and others, 2015), and a small, sharp, closed 

aeromagnetic low (Day and others, 2016), which may reflect the 

hydrothermal alteration. An anomalous gold concentration was 

noted in a stream-sediment sample from the center of the tract. 

Numerous active lode claims are in the tract (for example, Camino 

Minerals claims; fig. 1) and a pending notice for gold exploration 

(Fernette and others, 2016a). In addition, numerous closed lode 

claims are in the tract (Causey, 2007, 2011; fig. 12).

Tract SHEP02, Sheldon West—A moderate potential (M), 

with certainty level B, for epithermal mercury, gold, and silver 

deposits has been assigned to an area delineated by Eocene to 

Oligocene andesite and rhyolite flows in the western part of the 

Sheldon Antelope Refuge, Washoe County, Nevada (Crafford, 

2007; tract SHEP02, Sheldon West; fig. 14A; appendix 2). 

Mercury, gold, and silver mineralization occurs in rhyolite and 

andesite flows and ash-flow tuffs, and in sedimentary rocks that 

have locally been altered along northwest-trending fault zones 

(Ross, 1941). Mercury production (5 flasks) is reported from 

the Antelope Mine (Bailey and Phoenix, 1944; table 8) and 

numerous prospects for mercury, gold, and silver are present in 

the tract (Fernette and others, 2016a). Anomalous concentrations 

of mercury, antimony, silver, and gold with potentially ore grade 

concentrations of gold (1.4 parts per million [ppm]) and silver 

(113 ppm) are locally present at the surface in altered andesite 

(Tuchek and others, 1984). Many closed lode claims are in the 

tract (Causey, 2007, 2011; fig. 12). 

Buffering Epithermal Gold, Silver, and Mercury 

Tracts

The epithermal gold, silver, and mercury tracts described 

above were delineated from characteristics of epithermal 

gold, silver, and mercury deposits based on the deposit model, 

which was assembled from characteristics of well-documented 
Mineral-Resource Potential 39

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Assessment tract type—Epithermal gold-silver (mercury)

Moderate potential, low certainty

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Moderate potential, moderate certainty

EXPLANATION

A

SHEP02, Sheldon West, M/B

SHEP01, Coyote Hills, M/C

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Figure 14. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the 

study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon (San Juan and 

others, 2016); A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for sunstone; and C, Assessment tract for 

lacustrine diatomite. USGS, U.S. Geological Survey.
40 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Goose

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COUNTY HUMBOLDT

COUNTY

WASHOE

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HARNEY

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EXPLANATION

Assessment tract type—Sunstone

High potential, high certainty

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

SHSS01, Dust Devil, H/D

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

B

Figure 14. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the 

study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon (San Juan and 

others, 2016); A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for sunstone; and C, Assessment tract for 

lacustrine diatomite. USGS, U.S. Geological Survey.—Continued
Mineral-Resource Potential 41

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COUNTY HUMBOLDT

COUNTY

WASHOE

COUNTY

HARNEY

COUNTY

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COUNTY

CALIFORNIA NEVADA

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120°00' 118°30'

42°30'

42°00'

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Study areas

IDAHO

MONTANA

OREGON

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WASHINGTON

Assessment tract type—Lacustrine diatomite

Low potential, low certainty

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

EXPLANATION

C

SHDT01, Washoe-Lake-Harney, L/B

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Figure 14. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the 

study area for the Sheldon-Hart Mountain National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon (San Juan and 

others, 2016); A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for sunstone; and C, Assessment tract for 

lacustrine diatomite. USGS, U.S. Geological Survey.—Continued
42 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

epithermal gold, silver, and mercury deposits and the 

magmatic-hydrothermal systems that formed the deposits (Day 

and others, 2016; appendix 2). Some of these characteristics 

may be concealed (for example, altered rocks covered by 

younger rocks; drill-defined gold and silver resources; deposits 

identified by drill-hole intercepts with elevated gold and silver 

values), and do not appear on published maps (geologic; 

topographic) or in other publications. Gold and silver 

occurrences on published maps and in other publications were 

the first criterion used to delineate possible concealed and 

unmapped epithermal gold and silver deposits. Other criteria 

used include the alteration and geochemical signatures of the 

magmatic-hydrothermal systems that form epithermal gold 

and silver deposits. The approximate diameters of footprints 

(surface exposures) of well-exposed epithermal gold and silver 

systems, based largely on mapped gold and silver occurrences, 

alteration, and geochemistry, range from several hundreds of 

meters to about 10 km, and are mostly 10–20 km2 in the study 

areas (appendix 5). If the areas of well-exposed systems are 

geometrically represented by circles concentric to mapped or 

published gold and silver occurrences, then circles enclosing 

systems that formed epithermal gold and silver deposits in the 

study areas have radii of 1.8–2.6 km. Based on the distribution 

and spatial density of gold and silver occurrences in the study 

areas, a circle with radius of 3 km centered on occurrences 

was used to delineate tracts. Tract boundaries represent the 

merged circumferences of circles concentric to all gold and 

silver occurrences within the tract. 

Market Analyses of Gold, Silver, and Mercury

Market analyses of gold, silver, and mercury are provided in 

appendix 5 and section I of Day and others (2016). 

Mineral Potential Tracts for Gemstone Deposits 

and Lacustrine Diatomite Deposits 

Two mineral potential tracts for gemstones deposits and 

lacustrine diatomite deposits were delineated and rated: tract 

SHSS01, Dust Devil, which has high potential for sunstone 

deposits, and tract SHDT01, Washoe-Lake-Harney, which 

encloses extensive exposures of stratigraphic sections that 

contain lacustrine diatomite beds and stratigraphy favorable 

for lacustrine diatomite deposits.

Tracts SHSS01, Dust Devil—A high potential (H), with 

certainty level D, for sunstone deposits has been assigned to two 

areas of porphyritic basalts in the High Lava Plains of Oregon 

(tract SHSS01, Dust Devil; fig. 14B; appendix 2). The two 

areas of the tract cover basalt flows in which there are sunstone 

mines, prospects, active mining claims, and active, authorized, 

and pending plans of operations and notices (fig. 11; tables 4, 5). 

The age of the basalts in which the sunstones occur is uncertain 

(Walker and MacLeod, 1991). Three operating sunstone mines are 

in the tracts: the Dust Devil, Sunstone Butte, and Spectrum Mines 

Area (figs. 13, 14C; table 8). Several prospects and occurrences 

occur within the tracts. The northern tract contains 2 PLSS 

sections with authorized plans of operations and notices, 5 PLSS 

sections in which surface-management plans are pending, and 9 

PLSS sections in which surface-management plans for sunstone 

have been submitted (fig. 11; tables 6, 7). A 2-mi2

 area of the basalt 

flows that contain sunstones originally described by Peterson 

(1972) has been withdrawn from mineral entry and established 

by the BLM as a free public collecting area. In the mines and 

collecting area, sunstones are extracted from weathered basalt in 

the near surface. However, at the Sunstone Butte Mine that was 

discovered in 2011, the sunstones occur in fragmented basalt.

Sunstone, the Oregon state gemstone, is a variety of 

transparent plagioclase feldspar (labradorite) that contains 

small inclusions of native copper. The color of the sunstone 

systematically varies with the concentration and size of copper 

particles. Sunstones with less than 20 ppm copper are pale 

yellow, with about 100 ppm copper are green, and with as 

much as 200 ppm copper are red (Hofmeister and Rosstnan, 

1985). Multicolored sunstones that are red and green also occur. 

Sunstones have also been termed heliolites (Pough, 1983). 

Specimens of Oregon sunstones are on display in major museums 

in the world. Sunstones are typically valued at $100 per carat but 

high-quality red or green sunstones may command as much as 

$1,000 per carat.

Tract SHDT01, Washoe-Lake-Harney—This tract has low 

potential (L) for lacustrine diatomite deposits at certainty level 

B (fig. 14C; appendix 2). It covers areas of northern Washoe 

County, Nevada, and Lake and Harney Counties, Oregon. The 

tract includes Miocene to Holocene stratigraphic units from the 

Nevada (Crafford, 2007) and Oregon (Walker and MacLeod, 

1991) state geologic maps that include diatomite as a minor or 

incidental lithology among sedimentary units associated with 

volcanic units. Included in this tract is unit QTls, Holocene to 

Pliocene landslide and colluvium deposits with minor basalt 

and diatomite (Crafford, 2007) equivalent to unit Qls (Stewart 

and Carlson, 1978). Additionally, this tract transects a regional 

system of Miocene to Pleistocene lake deposits that variably 

host diatomite or diatomaceous sediments (Wallace, 2003). 

These units are represented in Nevada as unit Ts3 (Crafford, 

2007), which includes the following units from Stewart and 

Carlson (1978): units Tts (minus units Ttsx1, Trd, and Trdx1) 

of the High Rock sequence, unit Tvv Virgin Valley beds of 

Merriam (1907), and unit Ttc Thousand Creek beds of Merriam 

(1907). This paleolake system containing diatomite extends 

into Oregon where it is represented as unit Ts, semiconsolidated 

lacustrine tuffaceous sandstone and siltstone, concretionary 

claystone, ash and ashy diatomite, conglomerate, minor 

fanglomerate, vitric-crystal and vitric-lithic tuff, pumice lapilli 

tuff, and tuff breccia; and is approximately correlative with the 

Banbury Basalt and Chalk Hills Formation, both of the Idaho 

Group (Walker and Repenning, 1966; Walker and MacLeod, 

1991; Miller and others, 2002, 2005). The diatomite potential 

from three previous mineral resources assessments conducted 

in the tract area was moderate and at A or B certainty (U.S. 

Geological Survey and U.S. Bureau of Mines, 1989). No current 

or past mines, no identified prospects or occurrences, and no 
Mineral-Resource Potential 43

active BLM claims or notices for diatomite are in the tract area 

or within the study area.

Market Analysis of Diatomite

Market analysis of diatomite is provided in appendix 5 

and section I of Day and others (2016). 

Occurrence of Leasable Minerals

Leasable mineral commodities (leasable solid and fluid 

minerals) include oil and gas, geothermal, coal, and non-energy 

solid minerals, including phosphate, potash, and sodium. These 

commodities were not evaluated for assessment, but were 

qualitatively appraised for exploration and mining activity, lease 

status, and potential for deposits within the study area for the 

Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area. No production of leasable solid minerals 

(coal, phosphate, potash, and sodium) or production of leasable 

fluid minerals (oil and gas, and geothermal) has occurred in 

the study area. Favorable stratigraphy for coal, phosphate, 

and potash is not exposed, or has not been recognized, or 

is concealed within the study area. Based on comparison to 

deposits of these commodities elsewhere in the western United 

States with past or present production (including oil and gas 

fields, and geothermal fields), and current market conditions, 

neither concealed or exposed deposits of these commodities are 

likely to be explored for, or produced, in coming decades, with 

the possible exception of geothermal. 

Although no oil and gas and geothermal have been 

produced, these commodities occur, or have been explored 

for in the study area for the Sheldon-Hart Mountain National 

Wildlife Refuge Complex Sagebrush Focal Area. There 

are closed leases for oil and gas, geothermal, and sodium 

indicating that exploration for these commodities has occurred 

in recent years (table 4). 

Oil and Gas

There are 195 closed oil and gas leases in the study area 

for the Sheldon-Hart Mountain National Wildlife Refuge 

Complex Sagebrush Focal Area (table 4). There is one dry 

well within the USGS study area boundary but external to the 

proposed withdrawal area (fig. 15). Oil and gas exploration, 

assessment, and potential in the four study areas are described 

in report section “Introduction; Leasable Minerals.”

Geothermal

There are 69 closed geothermal leases in the study area for 

the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area (fig. 16; table 4). Geothermal exploration, 

assessment, and potential in the four study areas are described in 

report section “Introduction; Leasable Minerals.”

Occurrence of Salable Minerals

Salable commodities, mainly sand and gravel, and 

aggregate, have been produced at several sites in the study 

area for the Sheldon-Hart Mountain National Wildlife 

Refuge Complex Sagebrush Focal Area. There are 29 salable 

commodity sites (mineral materials sales sites), 11 of which are 

authorized (approved) and pending, and 18 of which are closed 

(fig. 17; table 4). There are 9 approved (authorized) sites that are 

sand and gravel, 1 approved (authorized) site is crushed stone, 

and 1 pending site is specialty stone (table 9). There are 2 mine 

sites, basalt quarries, that are within the proposed withdrawal 

area (Fernette and others, 2016a).

Table 9. Active (approved and pending) mineral material sales sites in the proposed 

withdrawal area within the study area for the Sheldon-Hart Mountain National Wildlife 

Refuge Complex Sagebrush Focal Area, Nevada and Oregon.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey 

System (PLSS) section that includes a proposed withdrawal area]

Commodity Number of approved sites Number of pending sites

Sand and gravel, gravel 2 0

Sand and gravel 7 0

Stone, crushed and broken 1 0

Stone, specialty 0 1
44 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Goose

Lake

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COUNTY HUMBOLDT

COUNTY

WASHOE

COUNTY

HARNEY

COUNTY

LAKE

COUNTY

CALIFORNIA NEVADA

OREGON

¬« Lakeview 140

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120°00' 118°30'

42°30'

42°00'

Map

area

Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

EXPLANATION

Oil and gas exploration well (dry)

BLM—Leasable commodities, energy: commodity; case disposition

 Oil and gas; closed

Oil and Gas Exploration

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Figure 15. Map showing Bureau of Land Management (BLM) oil and gas leases in the study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon (Dicken and San Juan, 2016; Gunther and others 2016a,b; 

IHS Energy Group, 2016). USGS, U.S. Geological Survey.
Mineral-Resource Potential 45

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OREGON

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42°30'

42°00'

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area

Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

EXPLANATION

BLM—Leasable commodities

Energy: commodity; case disposition

Geothermal; authorized

Geothermal; closed

Sodium; closed

Non energy solid minerals: commodity; case disposition 

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Geothermal sites

!(

*#

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Geothermal developing sites 9/02/14

USGS low-temperature systems

USGS moderate- and high-temperature systems

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Figure 16. Map showing Bureau of Land Management (BLM) geothermal and sodium leases in the study area for the Sheldon-Hart 

Mountain National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon (Williams and others, 2008a,b; Dicken and San 

Juan, 2016). USGS, U.S. Geological Survey.
46 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Goose

Lake

MODOC

COUNTY HUMBOLDT

COUNTY

WASHOE

COUNTY

HARNEY

COUNTY

LAKE

COUNTY

CALIFORNIA NEVADA

OREGON

¬« Lakeview 140

£¤395

120°00' 118°30'

42°30'

42°00'

Map

area

Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 119° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 MILES

0 10 20 30 KILOMETERS

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

BLM—Salable mineral commodities: commodity; case disposition

Stone (specialty, weathered, riprap, crushed, dimension);

 authorized

Stone (specialty, weathered, riprap, crushed, dimension);

 closed, expired

Sand and gravel; authorized, pending

Sand and gravel; closed, expired, rejected

Abrasive, feldspar; closed

EXPLANATION

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Figure 17. Map showing Bureau of Land Management (BLM) salable mineral commodity sites in the study area for the Sheldon-Hart 

Mountain National Wildlife Refuge Complex Sagebrush Focal Area, Nevada and Oregon (Dicken and San Juan, 2016). USGS, U.S. 

Geological Survey.
Mineral-Resource Potential of the Study Area for 

the Southeastern Oregon and North-Central Nevada 

Sagebrush Focal Area, Nevada and Oregon

Introduction

The study area for the Southeastern Oregon and NorthCentral Nevada Sagebrush Focal Area spans the border of 

Oregon and Nevada and includes parts of Humboldt County, 

Nevada, and Harney and Malheur Counties, Oregon (fig. 18). 

This report section describes the mineral potential of the proposed 

withdrawal area within the study area for the Southeastern 

Oregon and North-Central Nevada Sagebrush Focal Area. 

This study area includes parts of the proposed withdrawal 

area described in the “Introduction” section of this report. The 

proposed withdrawal area within this study area encompasses 

1,382,477 acres (~5,595 km2; 2,160 mi2) of which the Bureau of 

Land Management (BLM) manages 1,213,644 acres and the U.S. 

Forest Service manages 168,833 acres. 

Description of Geology

Neoproterozoic, Paleozoic, Mesozoic, and Cenozoic rocks 

are exposed within the study area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Nevada and Oregon, 

and the USGS study area boundary (fig. 19). Neoproterozoic 

and Paleozoic rocks include metamorphosed sedimentary 

rocks. Paleozoic and Mesozoic sedimentary and volcanic rocks 

(Cambrian to Triassic) in part comprise the Roberts Mountains, 

Golconda, and Fencemaker allochthons, and the Black Rock 

(Devonian to Triassic) and Pueblo (Jurassic) terranes. These 

allochthons and terranes were intruded by granitic rocks (Jurassic, 

Cretaceous, and Tertiary). Tertiary strata are predominantly 

volcanic lava flows and tuffs, and sedimentary rocks (Eocene, 

Miocene and Pliocene). Quaternary strata include volcanic 

rocks and surficial deposits. The allochthons and terranes were 

juxtaposed by compressional tectonism during the Mesozoic. 

The allochthons, terranes, and Tertiary volcanic strata have been 

laterally displaced by late Tertiary extensional tectonism which 

produced the modern landforms of alternating, north-southoriented mountain ranges separated by broad, relatively flat valleys 

(Basin and Range topography). Basin and Range topographic 

landforms and broad Tertiary volcanic uplands dominate the study 

area.

More complete descriptions of these strata and their 

tectonic evolution, are in report section “Introduction; 

Description of Geology.”

Mineral-Resource Potential

Mineral Deposit Types

Characteristics of metallic and nonmetallic locatable 

mineral deposits, prospects, and host rocks in the study area 

for the Southeastern Oregon and North-Central Nevada 

Sagebrush Focal Area, Nevada and Oregon (appendix 2), are 

compatible with classification of these deposits as epithermal 

gold, silver, mercury, and gallium deposits, volcanogenic 

uranium deposits, gemstone deposits, specialty clay deposits, 

hectorite (lithium-rich clay) deposits, zeolite deposits, and 

lacustrine diatomite deposits (Day and others, 2016). 

Epithermal gold, silver, mercury, and gallium deposits 

are shallowly formed vein, stockwork, disseminated, and 

replacement deposits that are mined primarily for gold and 

silver. Hot-spring-type mercury deposits are often the nearsurface expression of gold and silver deposits that occur at 

deeper levels below mercury-enriched sinter and volcaniclastic 

strata. Only one gallium deposit occurs in the study area and 

it is in volcaniclastic strata subjacent to mercury deposits also 

in volcaniclastic strata. Epithermal gold, silver, and mercury 

deposits in the western United States occur largely in EoceneMiocene volcanic fields, and have been mined primarily for 

gold and silver, and lesser mercury (on the basis of mass and 

value). No epithermal gallium deposits have been mined. 

Volcanogenic uranium deposits include veins, 

stockworks, and stratabound deposits in felsic volcanic rocks 

and associated volcanoclastic sediments and tuffs in which 

uranium minerals are concentrated in fractures, faults, feeder 

zones, flow breccias, and permeable strata. 

In the study area, gemstone and specialty clay deposits 

occur in Tertiary volcanic rocks that have been hydrothermally 

altered. There are few deposit type models for gemstone 

deposits because of the small size, small market, and limited 

number of most gemstone deposits, and because demand for 

most is based entirely on appearance. There are no deposit 

type models for specialty clay deposits because of small 

deposit size and market based on specific composition, color, 

purity, and other market factors.

Hectorite (lithium-rich clay) deposits form in closedbasin evaporative lake environments, including playas and 

calderas that contain large proportions of volcanic ash. 
48 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah 78

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OWYHEE

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IDAHO

OREGON

NEVADA

116°00' 117°00' 118°00' 119°00'

42°30'42°00'41°30'

Map

area

Study areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH NEVADA

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.Roads and political data copyright © 2014 Esri and its licensors.Boundary data from San Juan and others (2016).USA Contiguous Albers Equal Area Conic Projection.Central meridian, 118° W., latitude of origin, 37.5° N.North American Datum of 1983.

0 10 20 30 40 50 MILES0 10 20 30 40 50 KILOMETERS

EXPLANATION

Base data

USGS study area boundaryProposed withdrawal areasProposed withdrawal additionsState boundariesCounty boundaries

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Figure 18. Map showing proposed withdrawal areas that comprise the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon, and boundary of the U.S. Geological Survey (USGS) study area. The study area boundary corresponds to townships that enclose the proposed withdrawal areas.
116°00' 117°00' 118°00' 119°00'

42°30'42°00'41°30'

OWYHEE

COUNTY

ELKO

COUNTY

HUMBOLDT

COUNTY

HARNEYCOUNTY

MALHEUR

COUNTY

IDAHO

OREGON

NEVADA

Map

area

Study areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH NEVADA

WASHINGTON

Base modified from U.S. Geological Survey DEM data, 2016.Political data copyright © 2014 Esri and its licensors.Boundary data from San Juan and others (2016).USA Contiguous Albers Equal Area Conic Projection.Central meridian, 118° W., latitude of origin, 37.5° N.North American Datum of 1983.

0 10 20 30 40 50 MILES0 10 20 30 40 50 KILOMETERS

EXPLANATION

Base data

USGS study area boundaryState boundaries

Mesozoic granitic rocks (Cretaceous and Jurassic)

Pueblo terrane (Jurassic)Black Rock terrane (Triassic to Devonian)Golconda allochthon (Permian to Mississippian)Roberts Mountains allochthon (Devonian to Cambrian)Sedimentary rocks of the North Americancontinental shelf (Triassic to Neoproterozoic)Metamorphic rocks (Paleozoic and Neoproterozoic)

Surfical deposits (Quaternary)Volcanic rocks (Quaternary)

Fencemaker allochthon (Triassic) Mafic to intermediate lava flows (Pliocene and Miocene)

Rhyolite tuffs and lava flows (Pliocene and Miocene)Sedimentary rocks (Pliocene and Miocene)Volcanic and sedimentary rocks (early Miocene to Eocene)Intrusive rocks (Tertiary)

Generalized lithologic units (geologic age)

Water bodyCounty boundaries

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Mineral-Resource Potential 49

Figure 19. Simplified geologic map of the study area for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon. Synthesized from Walker and McLeaod (1991), Miller and others (2002), Crafford (2007), and Lewis and others (2012). USGS, U.S. Geological Survey.
50 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Deposits consist of elevated concentrations of hectorite and 

other lithium minerals that have replaced pre-existing smectite 

clay and other minerals in lacustrine sediments. Lithium is 

thought to be derived from leaching by hydrothermal fluids of 

adjacent and subjacent volcanic ash and alkaline rocks. 

Zeolite deposits consist of concentrations of numerous zeolite 

minerals in rhyolitic to dacitic vitric tuffs that have accumulated 

in arid, closed-basin, evaporative lake environments and have 

been altered by saline, carbonate-rich waters. Enclosing strata 

may include bedded evaporites (trona, halite, borates), mudstone, 

diatomite, and oil shale. 

Lacustrine diatomite deposits consist of chalklike, earthy 

siliceous sedimentary strata composed of diatoms. In volcanic 

terranes, diatomaceous lake sediments typically occur within 

sequences of volcanic and sedimentary rocks. Lacustrine diatomite 

deposits in the western United States occur primarily in high-silica 

sequences of middle Miocene flows and tuffs.

Geology and Occurrence of Mineral Deposit Types

The study area for the Southeastern Oregon and NorthCentral Nevada Sagebrush Focal Area is predominantly underlain 

by Tertiary and Quaternary volcanic and sedimentary rocks. 

Mesozoic granitic intrusions are exposed in the western and 

southern parts of the study area. The southernmost exposures 

of granitic rocks are surrounded by siliciclastic strata of the 

Fencemaker allochthon (fig. 19). Epithermal gold, silver, mercury, 

and gallium, volcanogenic uranium, gemstone, specialty clay, 

lithium, zeolite, and lacustrine diatomite deposits, occur in 

Tertiary volcanic flows, intrusions, tuffs, and associated epiclastic 

sedimentary strata of the McDermitt and Whitehorse calderas, 

Humboldt County, Nevada, and Malheur and Harney Counties, 

Oregon, in the western part of the study area. Epithermal gold, 

silver, and mercury deposits occur in Tertiary volcanic rocks of the 

Santa Rosa-Calico volcanic field in the northern part of the Santa 

Rosa Range, and orogenic low-sulfide gold-quartz vein deposits 

occur in Mesozoic siliciclastic strata in the southern part of the 

Santa Rosa Range, Humboldt County, Nevada; these deposits are 

in the southeastern part of the study area. 

Exploration and Mining Activity for Locatable 

Minerals

Metallic and nonmetallic locatable mineral commodities 

that have been mined and explored for in the study area for 

the Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Area include gold, silver, mercury, gallium, uranium, 

gemstones, specialty clays, hectorite (lithium-rich clay), 

zeolites, and diatomite. Numerous lode and placer claims have 

been staked in the study area (fig. 20; tables 10, 11), there is an 

active plan of operations for uranium and there are numerous 

closed plans of operations and notices, indicative of current and 

recent mineral exploration (fig. 20; tables 12, 13). In addition, 

numerous claims were staked and filed in the study area from 

1976 to 2007 (Causey, 2007, 2011; fig. 21).

Within the study area, two gold and silver deposits at 

the National and Buckskin National Mines were mined with 

recorded production of about 200,000 oz (troy ounces) gold 

and 760,000 oz silver (Vanderburg, 1938; Vikre, 1985b). Six 

mercury deposits (Cordero, Cordero [McDermitt], Bretz, 

Opalite, Ruja, and McCormick/Paradise) were mined with 

recorded production of about 408,000 flasks of mercury 

(Vanderburg, 1938; Yates, 1942; Bailey and Phoenix, 1944; 

Rytuba, 1976), and one uranium deposit was mined with 

recorded production of about 600 kilograms (kg) of uranium 

(Castor and Henry, 2000; table 14; fig. 22).

A resource of 138,351 short tons at 0.363 troy ounce per 

short ton gold and 3.37 troy ounces per short ton silver has 

been defined by drilling at the Buckskin National Mine. At the 

Cordero (McDermitt) Mine a mercury resource (1,070,000 short 

tons at 7.25 pounds [lbs] of mercury per ton) overlies a drillidentified gallium resource (21,562,700 million metric tons at 

46.5 ppm [parts per million] gallium). An estimated resource 

of 2,000–3,000 flasks of mercury remains at the McCormick/

Paradise Mine. Three uranium resources have been defined 

by drilling. The Kings Valley South and Kings Valley North 

resources (2,499,000 short tons at 0.076 weight percent U3

O8), 

Aurora resource (76,390,000 short tons at 248 ppm U3O8), and 

Moonlight Mine resource (479,000 short tons at 0.108 percent 

U3O8), are active exploration projects (table 14). The National, 

Buckskin National, and McCormick Mines are within the 

proposed withdrawal area. The mercury and gallium resources 

at the Cordero (McDermitt) Mine are outside the proposed 

withdrawal area and are inside the USGS study area boundary. 

The Kings Valley South and Kings Valley North uranium 

resources are outside the proposed withdrawal area.

Several plans of operations and notices of mineral 

exploration for lithium, clays, and gemstones have been 

authorized, are pending, or are active, indicating recent and active 

mineral exploration in the study area (fig. 20; tables 12, 13). 

Within the study area, a lithium resource of 823 million 

short tons at 0.30 percent lithium (Kings Valley Lithium; table 14) 

comprises five deposits that have been defined by drilling. The 

Stage I deposit, 374,443,027 short tons at 0.292 percent lithium 

occurs outside the proposed withdrawal area and within the USGS 

study area boundary. The Stage II, Stage III, Stage IV, and Stage 

V deposits have a combined resource of 449,528,206 short tons at 

0.304 percent lithium (Fernette and others, 2016a). 

A qualitative estimate of past mining activity for 

locatable metallic (and nonmetallic) mineral commodities was 

made by counting mining-related symbols on U.S. Geological 

Survey (USGS) topographic maps that cover the study area 

(Fernette and others, 2016b). There are 1,798 mine symbols 

shown on USGS 7.5-minute topographic maps, 99 of which 

are adits, shafts, or open-pit mines, and 1,634 are prospect 

pits. These symbols are commonly associated with mining 

and exploration of locatable minerals and provide a broad 

indication of the extent of past mining activity in the area. 

Other mine symbols include borrow pits, gravel pits, and 

cinder pits, which are commonly associated with production of 

salable minerals.
Mineral-Resource Potential 51

A second qualitative estimate of past mining activity 

was made by extracting mines and deposits with the 

statuses “producer” and “past producer” from the USGS 

Mineral Resources Data System (MRDS; U.S. Geological 

survey, 2005). The MRDS database contains 150 records of 

“producer” and (or) “past producer,” including 59 deposits 

Table 10. Type, number, and status of mining claims, leases, mineral material sales sites for salable mineral commodities, and surfacemanagement plans in the proposed withdrawal area within the study area for the Southeastern Oregon and North-Central Nevada 

Sagebrush Focal Area, Nevada and Oregon.

[Leasable mineral commodities include coal, geothermal, non-energy solid mineral, oil and gas. Sources: Dicken and San Juan (2016) for Bureau of Land Management 

(BLM) 43 Code of Federal Regulations (CFR) 3809 data; Susan G. Summer Elliott, U.S. Forest Service (USFS), written commun., March 9, 2016, for USFS 36 CFR 228 

Subpart A plans. The number of cases is for the complete Public Land Survey System (PLSS) section that includes a proposed withdrawal area. —, no data]

that were mined for metallic minerals, 46 for gemstones, 2 for 

uranium, 2 for industrial minerals, and the 41 for stone, sand, 

and gravel. However, it should be noted that some MRDS 

records may be duplicates. The MRDS database includes 

partial production data for one mine, the McDermitt mercury 

mine, but no production data for other mines.

Type Mineral 

type

Number of 

unique cases Active Authorized/Approved

Pending/

Proposed Closed Cancelled Expired Rejected Withdrawn

Mining claims Locatable 20,097 2,464 — — 17,633 — — — —

Coal leases Leasable — — — — — — — — —

Geothermal leases Leasable 29 — — — 29 — — — —

Non-energy solid mineral 

leases Leasable 8 — — — 8 — — — —

Oil and gas leases Leasable 135 — — — 135 — — — —

Mineral materials sales sites Salable 104 — 17 — 86 — 1 — —

Surface-management plans — 128 1 4 1 113 — 10 — —

Table 11. Summary of active and closed mining claims for locatable minerals in Public Land Survey System (PLSS) sections that are in the 

proposed withdrawal area within the study area for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada 

and Oregon.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete PLSS section that includes a proposed withdrawal area]

Area Active lode 

claims

Closed lode 

claims

Active placer 

claims

Closed placer 

claims

Active 

millsites

Closed 

millsites

Sections containing proposed withdrawal area 2,427 17,209 37 255 0 169

Table 12. Status and number of surface-management plans for locatable minerals in the proposed withdrawal area within the study 

area for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon.

[Sources: Dicken and San Juan (2016) for Bureau of Land Management (BLM) 43 Code of Federal Regulations (CFR) 3809 plans; Susan G. Summer Elliott, U.S. 

Forest Service (USFS), written commun., March 9, 2016, for USFS 36 CFR 228 Subpart A plans. The number of cases is for the complete Public Land Survey System 

(PLSS) section that includes a proposed withdrawal area. —, no data]

Authorization type Number of 

unique cases Active Authorized/Approved

Pending/

Proposed Closed Cancelled Expired Rejected Withdrawn

Plans of operations 13 1 2 — 10 — — — —

Notice 115 — 1 1 103 — 10 — —

Table 13. Status and number of active surface-management plans in the proposed withdrawal area within the study area for the 

Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon, summarized by locatable commodity.

[Active includes active, authorized/approved, and pending/proposed from table 12. Sources: Dicken and San Juan (2016) for Bureau of Land Management (BLM) 

43 Code of Federal Regulations (CFR) 3809 plans; Susan G. Summer Elliott, U.S. Forest Service (USFS), written commun., March 9, 2016, for USFS 36 CFR 228 

Subpart A plans. The number of cases is for the complete Public Land Survey System (PLSS) section that includes a proposed withdrawal area]

Commodity Active notices Active plans of operations

Gold and silver 0 1

Clay, common 1 0

Gemstone, semiprecious silica 1 0

Lithium 0 1

Uranium and other minerals 0 1
52 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Figure 20. Map showing active and closed surface-management plans of operations and notices for locatable mineral 

commodities in the study area for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Oregon and Nevada, 

including data from the Bureau of Land Management (Dicken and San Juan, 2016, 43 Code of Federal Regulations [CFR] 3809 data) 

and the U.S. Forest Service (Susan G. Summer Elliott, U.S. Forest Service [USFS], written commun., March 9, 2016, for USFS 36 CFR 

228 Subpart A plans). USGS, U.S. Geological Survey.
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Northern Nevada 

Study Area

BLM—Locatable commodities: commodity; case disposition; case type

Gold, gold lode, gold placer, copper; closed, expired, cancelled;

 surface management-notice

Gold, gold lode; closed; surface management-plan

Uranium and other minerals; authorized; surface management-plan

Uranium, uranium and other minerals, uranium, (U3O8 content);

 closed; surface management-notice

Uranium and other minerals; closed; surface management-planwithdrawal-review

Lithium; authorized; surface management-plan

Lithium; authorized, pending; surface management-notice

Lithium; closed; surface management-notice

Mercury; closed; surface management-notice

Rare earths; closed; surface management-notice

Clay, bentonite; closed, expired; surface management-notice

Other (all locatables, none, to be defined) 

EXPLANATION

U.S. Forest Service—Management plans

Active

Inactive

Mineral-Resource Potential 53

Figure 20.—Continued
54 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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A

Figure 21. Maps showing mining claims by Public Land Survey System (PLSS) section in the study area for the Southeastern Oregon 

and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon. A, Number of active lode claims and placer claims per section 

(Dicken and San Juan, 2016). B, Thirty-five year averages of the number of active lode claims by section for mining claims located 

between 1976 and 2010 (Causey, 2007, 2011).
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Southern Idaho and

Northern Nevada 

Study Area

EXPLANATION

Number of active lode claims per section

1–8

9–21

22–36

37–51

52–82

Sections with only closed claims (including placer)

Sections with one or more active placer claims outlined in white

Mineral-Resource Potential 55

Figure 21.—Continued
56 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

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B

Figure 21. Maps showing mining claims by Public Land Survey System (PLSS) section in the study area for the Southeastern Oregon 

and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon. A, Number of active lode claims and placer claims per section 

(Dicken and San Juan, 2016). B, Thirty-five year averages of the number of active lode claims by section for mining claims located 

between 1976 and 2010 (Causey, 2007, 2011).
Mineral-Resource Potential 57

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6.27–43.27

3.03–6.26

1.46–3.02

0.38–1.45

0.01–0.37

Base data

USGS study area boundary

Proposed withdrawal areas

Proposed withdrawal additions

State boundaries

County boundaries

EXPLANATION

Southern Idaho and

Northern Nevada 

Study Area

Thirty-five year average of the number of active lode claims by section

Figure 21.—Continued
58 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

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Figure 22. Map showing mining districts, mine status, and active exploration areas in or near the study area for the Southeastern 

Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (Fernette and others, 2016a,b). USGS, U.S. Geological 

Survey.
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Active exploration areas

EXPLANATION

Mine status

Active

Inactive

Uncertain

Mining districts

!(

!(

!(

!( No data

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County boundaries

Mineral-Resource Potential 59

Figure 22.—Continued
60 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah Table 14. Mined deposits with production, and resources within and partly within the study area for the Southeastern Oregon and North-Central Nevada Focal Area. [Data from technical reports, including NI 43-101 documents, are in Fernette and others, 2016a. Nevada mining districts are from Tingley (1992). One flask of mercury = 76 pounds of mercury; est., estimate; g/ metric ton, grams per metric ton; kg, kilogram; lbs, pounds; M+I+I, measured plus indicated plus inferred; MST, million short tons; NV, Nevada; opt, troy ounce per short ton; OR, Oregon; oz, troy ounce; ppm, part per million; ST, short ton; U O3 8, triuranium octoxide; @, at; %, weight percent; $, U.S. dollars; M, million] Mine/Deposit name Assessment tract name Mining district County, state Commodity Production years Production Resource Notes; source National Mine ONEP03, Buckskin National Humboldt, NV Gold and silver 1909–1929 175,502 oz gold; 457,190 oz silver — Vanderburg (1938) Buckskin National Mine ONEP03, Buckskin National Humboldt, NV Gold and silver 1908–1941 24,000 oz gold; 300,000 oz silver 138,351 ST @ 0.363 opt gold; 3.37 opt silver Fernette and others (2016a), Vikre (1985b) McCormick/Paradise Mine ONEP03, Buckskin National Humboldt, NV Mercury 1930s 58 flasks mercury Est. 2,000–3,000 flasks Vanderburg (1938), Roberts (1940) Silver Butte claims ONEP04, Paradise Valley Paradise Valley Humboldt, NV Silver and gold 1879/1935 Est. $1.5–3M — Vanderburg (1938) Cordero ONEP01, Cordero Opalite Humboldt, NV Gold and silver — — — — Cordero Mine ONEP01, Cordero Opalite Humbolt, NV Mercury 1941–43 105,636 flasks mercury — Yates (1942); Bailey and Phoenix (1944); Rytuba (1976); Speer (1977); NI 43-101 NV Cordero Gold Silver Project August 1, 2007 technical report; Fernette and others (2016a) Cordero (McDermitt) Mine ONEP01, Cordero Opalite Humbolt, NV Mercury 1975–1986 269,580 flasks mercury 1,070,000 ST @ 7.25 lbs mercury/ST Bretz Mine ONEP01, Cordero Opalite Malheur, OR Mercury 1931–1968 14,807 flasks mercury —

Opalite Mine ONEP01, Cordero Opalite Malheur, OR Mercury — 12,367 flasks mercury —Ruja ONEP01, Cordero Opalite Humbolt, NV Mercury — 6,000 flasks mercury —Cordero (McDermitt) 

Mine

ONEP01, Cordero Opalite Humboldt, NV Gallium — — 21,562,700 million 

metric tons @ 46.5 ppm gallium (M+I+I)

Carew (2008)

Moonlight Mine ONVU01, Kings 

Valley 

Opalite Humboldt, NV Uranium — 600 kg (~1,320 lbs) 479,000 ST @ 0.108% 

U O3 8

Castor and Henry (2000), Fernette and others 

(2016a)

Kings Valley South; 

Kings Valley North

ONVU01, Kings 

Valley 

Opalite Humboldt, NV Uranium — — 2,499,000 ST @ 0.076% 

U O3 8

NI 43-101 NV Kings Valley Project December 

20, 2007 technical report; Eggleston and others (2007)

Aurora ONVU01, Kings 

Valley 

Opalite Malheur, OR Uranium — — 76,390,184 ST @ 248 

ppm U O3 8

https://aurorauraniumlimited.wordpress.

com/projects/, accessed January 14, 2016; Meyers and Underhill (2005)

Kings Valley Lithium ONVU01, Kings 

Valley 

Opalite Humboldt, NV Lithium — — 823 MST @ 0.30% 

lithium

Tetra Tech (2014), Eggleston (2008)
Mineral-Resource Potential 61

Mineral Potential of Locatable Minerals

Potential for undiscovered deposits of locatable mineral 

commodities (metallic locatable minerals and nonmetallic locatable 

minerals) within this study area was evaluated for the locatable 

commodities gold, silver, mercury, gallium, uranium, gemstones, 

lithium, specialty clays, zeolites, and diatomite. These mineral 

commodities were selected for evaluation on the basis of deposits 

in this study area with production and (or) defined resources, 

prospects, hydrothermal alteration, stratigraphy and structure 

of host rocks, and other geological characteristics of deposit 

types for these commodities (Day and others, 2016; appendix 2; 

table1). Records of active and historic mining claims and surfacemanagement plans provided by the BLM and USFS were also used 

in the assessment process. Mineral-resource potential is represented 

by rated tracts; tracts consist of areas favorable for undiscovered 

deposits of one or more commodities that are enclosed by tract 

boundaries, assigned qualitative potential (high, moderate, or low/

permissive), and assigned a level of potential certainty. The tract 

boundaries include a buffer of variable dimension that reflects 

spatial uncertainty of one or more of the characteristics used to 

delineate the tract. The qualitative mineral potential ratings are 

derived from a classification matrix that merges mineral potential 

and level of certainty (appendix 1). 

Delineation and rating of tracts are based entirely on 

publications available from libraries and Web sites, and on 

technical reports, documents, and maps available from Web sites, 

downloaded from Web sites that are no longer maintained, and 

provided by companies with mineral rights on lands included in 

the proposed withdrawal area. The technical reports, documents, 

and maps that are not available on Web sites, and those provided 

by companies, can be accessed in a database that includes mineral 

deposits with production and resources, and mineral exploration 

sites within the study areas (Fernette and others, 2016a). All 

publications, technical reports, documents, and maps used to 

delineate and rate tracts are cited in tract descriptions, in tables 

of tract characteristics, and in tables of deposit production, 

resources, and mineral exploration sites. We did not perform field 

examinations, mapping, or analyses of the tracts, deposits, and 

resources described in this report section. 

Mineral Potential Tracts for Epithermal Gold, 

Silver, Mercury, and Gallium Deposits

Four mineral potential tracts for epithermal gold, silver, 

mercury, and gallium deposits were delineated and rated in the 

study area: tract ONEP01, Cordero (mercury, gold, silver, and 

gallium); tract ONEP02, Lucky Boy (mercury); tract ONEP03, 

Buckskin (gold, silver, and mercury); and tract ONEP04, Paradise 

Valley (silver and gold).

Tract ONEP01, Cordero—A high potential (H), with certainty 

level D, for epithermal mercury, gold, silver, and gallium deposits 

is assigned to a tract delineated by the observed and inferred 

distribution of caldera-ring fractures and postcaldera intrusions in 

the McDermitt caldera, Humboldt County, Nevada, and Malheur 

County, Oregon (tract ONEP01, Cordero; fig.23A; appendix 2; 

Rytuba, 1976). The distribution of postcaldera intrusions in the 

subsurface is reflected by aeromagnetic high anomalies that 

occur inboard of the caldera margin (U.S. Geological Survey, 

Department of Interior and the National Geophysical Data Center, 

NOAA, 2002). The tract includes the Opalite Mining District 

(Tingley, 1992) which contains the McDermitt, Cordero, Bretz, 

Opalite, and Ruja Mines that have a total production of 10,530 

short tons of mercury (Yates, 1942; Bailey and Phoenix, 1944; 

Rytuba, 1976; table 14). The mercury deposits occur in tuffs and 

caldera-fill sediments that have been altered to an assemblage of 

adularia, quartz, opal, and clays in and adjacent to the ring fracture 

zone of the caldera (Rytuba and Glanzman, 1979). Mercury ore 

minerals are primarily cinnabar, corderoite, and elemental mercury 

in association with pyrite and the antimony minerals, stibnite, and 

stibiconite (Rytuba and others, 2003).

Other prospects within the caldera ring fracture zone, 

primarily the northwest part of the caldera, have been the 

focus of exploration and drilling for gold and silver, and active 

claims are present in the Albisu-Corral Canyon area. Extensive 

drilling has delineated a low-grade gold resource in stockwork 

veins that contain sulfide±quartz±calcite and occur in tuffs and 

basalt (Concordia Resources Corporation, 2011). The surface 

manifestations of these deposits are characterized by hydrothermal 

illite that has been mapped using ASTER (Advanced Spaceborne 

Thermal Emission and Reflection Radiometer) remote-sensing 

imagery (Rockwell and others, 2015).

Elevated concentrations of gallium occur in caldera-filling 

tuffs and flows located below the near-surface McDermitt 

mercury deposit. A measured and indicated NI 43-101-compliant 

resource consists of 14.97 million short tons at 47.7 ppm gallium, 

and anomalous gallium and light rare earth element (REE) 

concentrations, occur in a wide area outside the established 

resource (Carew, 2008). Gallium occurs in zones of alunitekaolinite-quartz alteration developed along caldera ring fracture 

faults (Rytuba and others, 2003). Low-grade uranium is associated 

with the Bretz and Opalite mercury deposits (Roper and Wallace, 

1981; Berry and others, 1982). Numerous active lode and placer 

claims are in the tract, as well as many closed lode claims (fig. 21; 

Causey, 2007, 2011).

Tract ONEP02, Lucky Boy—A moderate potential (M), with 

certainty level C, for epithermal mercury deposits is assigned 

to areas delineated by the observed and inferred distribution of 

caldera ring fracture of the Whitehorse caldera and postcaldera 

domes and intrusions, Harney and Malheur Counties, Oregon 

(tract ONEP02, Lucky Boy; fig. 23A; appendix 2; Rytuba and 

others, 1981). The western boundary of the caldera is coincident 

with an oval aeromagnetic low anomaly that extends beyond 

the caldera margin on the east side of the caldera. Hydrothermal 

alteration of the rhyolite domes consists of silicification and 

argillic alteration and presence of quartz and chalcedony veins 

(Rytuba and others, 1981). Two gold and silver prospects, Lucky 

Boy and Flagstaff Butte, without identified resources are present 

(Fernette and others, 2016a). Extensive drilling by several mining 

companies has occurred at the Flagstaff Butte prospect (Ferns and 

others, 1986; Hladky, 1993). Numerous active lode and placer 
62 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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ONEP01, Cordero, H/D

ONEP03, Buckskin, H/D

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A

Figure 23. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the study area 

for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (San Juan and others, 2016); USGS, U.S. 

Geological Survey; A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for volcanogenic uranium; C, Assessment 

tract for orogenic low-sulfide gold-quartz veins; D, Assessment tract for specialty gemstone; E, Assessment tracts for hectorite (lithium-rich clay); 

F, Assessment tracts for specialty clay; G, Assessment tracts for zeolites; and H, Assessment tracts for lacustrine diatomite.
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Assessment tract type—Epithermal gold-silver (mercury)

Moderate potential, moderate certainty

Base data

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Proposed withdrawal areas

EXPLANATION

High potential, high certainty

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 24A. Tracts ONEP01, ONEP02, ONEP03, ONEP04.

Southern Idaho and

Northern Nevada 

Study Area

Mineral-Resource Potential 63

Figure 23.—Continued
64 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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ONVU01, Kings Valley, H/D

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Nor

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Figure 23. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the study area 

for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (San Juan and others, 2016); USGS, U.S. 

Geological Survey; A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for volcanogenic uranium; C, Assessment 

tract for orogenic low-sulfide gold-quartz veins; D, Assessment tract for specialty gemstone; E, Assessment tracts for hectorite (lithium-rich clay); 

F, Assessment tracts for specialty clay; G, Assessment tracts for zeolites; and H, Assessment tracts for lacustrine diatomite.
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UTAH

NEVADA

WASHINGTON

Assessment tract type—Volcanogenic uranium (Aurora and Kings River type)

Base data

USGS study area boundary

Proposed withdrawal areas

EXPLANATION

High potential, high certainty

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B Figure 24B. Tract ONVU01.

thern Idaho and

rthern Nevada 

Study Area

Mineral-Resource Potential 65

Figure 23.—Continued
66 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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COUNTY

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NEVADA

OREGON

119°00' 118°00' 117°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

ONOG01, Orovada, M/C

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

S

N

Nevada additions

C

Figure 23. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the study area 

for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (San Juan and others, 2016); USGS, U.S. 

Geological Survey; A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for volcanogenic uranium; C, Assessment 

tract for orogenic low-sulfide gold-quartz veins; D, Assessment tract for specialty gemstone; E, Assessment tracts for hectorite (lithium-rich clay); 

F, Assessment tracts for specialty clay; G, Assessment tracts for zeolites; and H, Assessment tracts for lacustrine diatomite.
OWYHEE

COUNTY

ELKO

COUNTY

IDAHO

116°00'

Map

area

Study

 areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH

NEVADA

WASHINGTON

Assessment tract type—Orogenic low-sulfide gold-quartz vein

Base data

USGS study area boundary

Proposed withdrawal areas

EXPLANATION

Moderate potential, moderate certainty

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 24C. Tract ONOG01.

outhern Idaho and

Northern Nevada 

Study Area

Mineral-Resource Potential 67

Figure 23.—Continued
68 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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OREGON

119°00' 118°00' 117°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

ONAG01, McDermitt Gemstones, H/D

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Souther

Northe

Stu

Nevada additions

D

Figure 23. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the study area 

for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (San Juan and others, 2016); USGS, U.S. 

Geological Survey; A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for volcanogenic uranium; C, Assessment 

tract for orogenic low-sulfide gold-quartz veins; D, Assessment tract for specialty gemstone; E, Assessment tracts for hectorite (lithium-rich clay); 

F, Assessment tracts for specialty clay; G, Assessment tracts for zeolites; and H, Assessment tracts for lacustrine diatomite.
OWYHEE

COUNTY

ELKO

COUNTY

IDAHO

116°00'

Map

area

Study

 areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH

NEVADA

WASHINGTON

Assessment tract type—Specialty gemstone

Base data

USGS study area boundary

Proposed withdrawal areas

EXPLANATION

High potential, high certainty

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 24D. ONAG01.

rn Idaho and

ern Nevada 

udy Area

Mineral-Resource Potential 69

Figure 23.—Continued
70 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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COUNTY

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OREGON

119°00' 118°00' 117°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

ONLI01, West Lith, H/D

ONLI02, Whitehorse Lithium, M/B

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Nevada additions

E

Figure 23. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the study area 

for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (San Juan and others, 2016); USGS, U.S. 

Geological Survey; A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for volcanogenic uranium; C, Assessment 

tract for orogenic low-sulfide gold-quartz veins; D, Assessment tract for specialty gemstone; E, Assessment tracts for hectorite (lithium-rich clay); 

F, Assessment tracts for specialty clay; G, Assessment tracts for zeolites; and H, Assessment tracts for lacustrine diatomite.
OWYHEE

COUNTY

ELKO

COUNTY

IDAHO

116°00'

Map

area

Study

 areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH

NEVADA

WASHINGTON

Assessment tract type—Hectorite (lithium-rich clay)

Base data

USGS study area boundary

Proposed withdrawal areas

EXPLANATION

High potential, high certainty

Moderate potential, low certainty

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 24E. Tracts ONLI01, ONLI02.

Southern Idaho and

Northern Nevada 

Study Area

Mineral-Resource Potential 71

Figure 23.—Continued
72 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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COUNTY

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OREGON

119°00' 118°00' 117°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

ONCL02, Whitehorse Clay, M/B

ONCL01, Colloid, H/D

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Nevada additions

F

Figure 23. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the study area 

for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (San Juan and others, 2016); USGS, U.S. 

Geological Survey; A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for volcanogenic uranium; C, Assessment 

tract for orogenic low-sulfide gold-quartz veins; D, Assessment tract for specialty gemstone; E, Assessment tracts for hectorite (lithium-rich clay); 

F, Assessment tracts for specialty clay; G, Assessment tracts for zeolites; and H, Assessment tracts for lacustrine diatomite.
OWYHEE

COUNTY

ELKO

COUNTY

IDAHO

116°00'

Map

area

Study

 areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH

NEVADA

WASHINGTON

Assessment tract type—Specialty clay

High potential, high certainty

Moderate potential, low certainty

Base data

USGS study area boundary

Proposed withdrawal areas

EXPLANATION

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 24F. Tracts ONCL01, ONCL02.

Southern Idaho and

Northern Nevada 

Study Area

Mineral-Resource Potential 73

Figure 23.—Continued
74 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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COUNTY

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COUNTY

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OREGON

119°00' 118°00' 117°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

ONZE01, Nor Zeo, H/D

ONZE02, Whitehorse Zeolite, M/C

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

S

Nevada additions

G

Figure 23. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the study area 

for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (San Juan and others, 2016); USGS, U.S. 

Geological Survey; A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for volcanogenic uranium; C, Assessment 

tract for orogenic low-sulfide gold-quartz veins; D, Assessment tract for specialty gemstone; E, Assessment tracts for hectorite (lithium-rich clay); 

F, Assessment tracts for specialty clay; G, Assessment tracts for zeolites; and H, Assessment tracts for lacustrine diatomite.
OWYHEE

COUNTY

ELKO

COUNTY

IDAHO

116°00'

Map

area

Study

 areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH

NEVADA

WASHINGTON

Assessment tract type—Zeolites

Base data

USGS study area boundary

Proposed withdrawal areas

EXPLANATION

High potential, high certainty

Moderate potential, moderate certainty

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 24G. Tracts ONZE01, ONZE02.

Southern Idaho and

Northern Nevada 

Study Area

Mineral-Resource Potential 75

Figure 23.—Continued
76 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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COUNTY

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COUNTY

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OREGON

119°00' 118°00' 117°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

ONDT01, Whitehorse Diatomite, M/C

ONDT02, Harney-Malheur, L/B

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Nevada additions

H

Figure 23. Maps showing assessment tracts and level of resource potential for metallic and nonmetallic locatable minerals in the study area 

for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (San Juan and others, 2016); USGS, U.S. 

Geological Survey; A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for volcanogenic uranium; C, Assessment 

tract for orogenic low-sulfide gold-quartz veins; D, Assessment tract for specialty gemstone; E, Assessment tracts for hectorite (lithium-rich clay); 

F, Assessment tracts for specialty clay; G, Assessment tracts for zeolites; and H, Assessment tracts for lacustrine diatomite.
OWYHEE

COUNTY

ELKO

COUNTY

IDAHO

116°00'

Map

area

Study

 areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH

NEVADA

WASHINGTON

Assessment tract type—Lacustrine diatomite

Low potential, low certainty

Moderate potential, moderate certainty

Base data

USGS study area boundary

Proposed withdrawal areas

EXPLANATION

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 24H. Tracts ONDT01, ONDT02.

Southern Idaho and

Northern Nevada 

Study Area

Mineral-Resource Potential 77

Figure 23.—Continued
78 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

claims are in the tract, as well as many closed lode claims (fig. 21; 

Causey, 2007, 2011).

Tract ONEP03, Buckskin—A high potential (H), at certainty 

level D, for epithermal gold, silver, and hot spring mercury 

deposits is assigned to an area around Buckskin Mountain in 

the northern Santa Rosa Range, Humboldt County, Nevada 

(tract ONEP03, Buckskin; fig.23A; appendix 2). This area, 

which is within the National district (Tingley, 1992), includes a 

middle Miocene eruptive center that consists of a rhyolite flow 

dome complex and volcaniclastic sedimentary rocks overlying 

intermediate lava flows and breccias (Vikre, 1985a,b, 2007). 

The eruptive center is related to the early Yellowstone Hot Spot 

magmatism (Brueseke and others, 2007). The Miocene rocks were 

deposited on Jurassic-Triassic metasedimentary rocks of the Auld 

Lang Syne Group that were intruded by Late Cretaceous granitic 

plutons (Vikre, 1985b). Surficial hydrothermal deposits that form a 

mineralized hot spring system, including pool sinter and silicified 

sediments, cap Buckskin Mountain and are related to the rhyolite 

dome complex (Vikre, 2007). At deeper levels, this hydrothermal 

system formed epithermal quartz veins along north-striking highangle faults. Mining of the Bell vein on the east flank of Buckskin 

Mountain produced 24,000 oz gold and 300,000 oz silver from 

1906 to 1941, and mining of other middle Miocene epithermal 

veins in the National district produced 177,538 oz gold and 

471,541 oz silver during 1909–1936. Small amounts of mercury 

were produced from sinter and silicified clastic sedimentary rocks 

near the top of Buckskin Mountain (Roberts, 1940; Vikre, 1985b).

The tract was delineated using a 3-km buffer around deposits 

and prospects. Geologic mapping (Vikre, 1985a, 2007; Weiss and 

others, 2015) and interpreted ASTER remote-sensing imagery 

(Rockwell and others, 2015) were the basis for delineating strong 

argillic and advanced argillic alteration at Buckskin Mountain 

that underlie surficial hot spring deposits and overlie epithermal 

veins; the tract encompasses this alteration. Stream-sediment 

samples from the tract locally have anomalous concentrations of 

gold, arsenic, and copper. The tract contains numerous active lode 

claims, an active plan of operations, and closed notices and lode 

claims (figs. 20, 21; Causey, 2007, 2011). 

Tract ONEP04, Paradise Valley—A moderate potential 

(M), at certainty level C, for epithermal silver and gold 

deposits is assigned to the Red Hills at the northeast end of 

Paradise Valley, Humboldt County, Nevada (tract ONEP04, 

Paradise Valley; fig. 23A; appendix 2). This area includes 

Jurassic-Triassic metasedimentary rocks of the Auld Lang 

Syne Group that are intruded by a Cretaceous granitic pluton 

and overlain by a middle Miocene rhyolite dome complex and 

associated rhyolite lava flows (Willden, 1964; Crafford, 2007). 

Miocene mafic lava flows overlie hydrothermally altered 

rhyolites on the east side of the area. Some silver-rich quartz 

veins in the metasedimentary rocks are associated with clayaltered rhyolite porphyry dikes in the Paradise Valley district 

(Silver Butte Mine; Vanderburg, 1938; Bonham and others, 

1985; Tingley, 1992), and were mined on a small scale in the 

late 19th century. 

The tract was delineated using a 3-km buffer around 

small quartz vein deposits in Mesozoic metasedimentary 

rocks. The eastern part of the tract includes extensive areas 

of advanced argillic, argillic, and sericite-smectite alteration 

in Miocene rhyolite that is delineated by interpreted ASTER 

remote-sensing imagery (Rockwell and others, 2015). Streamsediment samples have anomalous concentrations of silver, 

arsenic, and lead, and composite hydrothermal mineralization 

geochemical anomalies (Ludington and others, 2006). An 

aeromagnetic low coincides with the altered rhyolites. Several 

active lode claims are in the area, as well as numerous closed 

lode claims and closed notices that indicate recent exploration 

activity (fig. 21; Causey, 2007, 2011).

Buffering Epithermal Mercury, Gold, Silver, and 

Gallium Tracts

The epithermal gold, silver, mercury, and gallium tracts 

described above were delineated from characteristics of epithermal 

gold, silver, and mercury deposits on the basis of the deposit 

model, which was assembled from characteristics of welldocumented epithermal gold, silver, and mercury deposits and 

the magmatic-hydrothermal systems that formed the deposits 

(Day and others, 2016; appendix 2; gallium is not included in the 

deposit model because of the rarity of gallium deposits). Some of 

these characteristics may be concealed (for example, altered rocks 

covered by younger rocks; drill-defined gold and silver resources; 

deposits identified by drill-hole intercepts with elevated gold and 

silver values) and do not appear on published maps (geologic; 

topographic) or in other publications. Gold and silver occurrences 

on published maps and in other publications were the first criterion 

used to delineate possible concealed and unmapped epithermal 

gold and silver deposits. Other criteria used include the alteration 

and geochemical signatures of the magmatic-hydrothermal 

systems that form epithermal gold and silver deposits. The 

approximate diameters of footprints (surface exposures) of wellexposed epithermal gold and silver systems, based primarily on 

mapped gold and silver occurrences, alteration, and geochemistry, 

range from several hundred meters to about 10km, and are

mostly 10–20 km2 in the study areas for the Sagebrush Focal 

Areas (appendix 5). If the areas of well-exposed systems are 

geometrically represented by circles concentric to mapped or 

published gold and silver occurrences, then circles enclosing 

systems that formed epithermal gold and silver deposits in the 

study areas have radii of 1.8–2.6 km. Based on the distribution 

and spatial density of gold and silver occurrences in the study 

areas, a circle with radius of 3 km centered on occurrences was 

used to delineate tracts. Tract boundaries represent the merged 

circumferences of circles concentric to all gold and silver 

occurrences within the tract. 

Mineral Potential Tract for Volcanogenic 

Uranium Deposits

One mineral potential tract for volcanogenic uranium 

deposits was delineated and rated in this study area: tract 

ONVU01, Kings Valley.
Mineral-Resource Potential 79

Tract ONVU01, Kings Valley—A high potential (H), with 

certainty level D, for volcanogenic uranium deposits (Auroratype and Moonlight-King River-type) is assigned to areas within 

the McDermitt caldera (tract ONVU01, Kings Valley; fig. 23B; 

appendix 2). The Kings Valley tract is delineated by the mapped 

McDermitt caldera margin buffered by 1 km to include uncertainty 

of the caldera margin. The tract includes uranium deposits, 

mapped and inferred subsurface flows and rhyolite caldera ring 

intrusions and domes, and caldera-fill sediments within the caldera 

that host uranium deposits. The McDermitt caldera is among 

the most highly mineralized calderas in the world and contains 

significant deposits of uranium. The potential for Aurora-type 

uranium mineralization is based on characteristics of the Aurora 

uranium deposit which occurs in intermediate composition ironrich lavas that fill the moat of the caldera. The Aurora deposit has 

a measured resource of 18.9 million pounds (Mlbs) triuranium 

octoxide U3O8 with a cutoff grade of 0.025 percent (Myers and 

Underhill, 2005). The uranium minerals uraninite, coffinite, 

and uranyl phosphates and uranium silicate have precipitated in 

the vesicles of lava flows (icelandites) and in flow breccias and 

fractures (Roper and Wallace, 1981). Alteration minerals include 

pyrite, fluorite, potassium feldspar, and chalcedony and opal. 

Other elements enriched in the deposit include arsenic, barium, 

mercury, molybdenum, antimony, and tungsten (Castor and Henry, 

2000). The lavas are covered by caldera lake sedimentary rocks 

and are exposed in limited areas. On the eastside of the caldera a 

geochemical anomaly of uranium, arsenic, and molybdenum in 

stream sediments indicates the potential for Aurora-type uranium 

mineralization in lava flows inferred to be present below caldera 

lake sediments in this area of the caldera.

The Moonlight-Kings River-type volcanogenic uranium 

deposits occur adjacent to rhyolite intrusions emplaced along the 

caldera ring fracture zone. The rhyolite intrusions are associated 

with a continuous series of aeromagnetic high anomalies that are 

inboard of the caldera margin and are interpreted to reflect rhyolite 

intrusions permissive for uranium deposits. The Moonlight Mine 

produced about 600 kg of U3

O8 at an average grade of 0.13 percent 

(Castor and Henry, 2000). Drilling along the western caldera ring 

fracture north of the Moonlight Mine has delineated a number of 

uranium deposits that are related to subsurface rhyolite intrusions. 

This mineralized zone has a measured resource of 4.838 Mlbs of 

U3

O8 with a cutoff grade of 0.035 percent for the North Zone and 

a cutoff grade of 0.050 percent for the South Zone and Moonlight 

Mine area (Eggleston and others, 2007). The uranium minerals 

include uraninite, coffinite, and uraniferous zircon, and the 

deposits are enriched in arsenic, gold, silver, molybdenum, and 

antimony (Castor and Henry, 2000).

Stratabound uranium deposits with a grade of 0.02 percent 

uranium occurs in a 2-m thick zone of silicified caldera-fill 

sedimentary rocks northwest of the Aurora uranium deposit, and 

drilling has documented this mineralized zone over a 3-km2 area 

(Roper and Wallace, 1981). This type of uranium mineralization 

is permissive throughout the area of the caldera where calderafill sediments are present.

A large low-grade resource of uranium occurs in altered 

tuffs and flow breccias associated with rhyolite domes in the 

southwest of part of the McDermitt caldera (Castor and Henry, 

2000). The rhyolite domes are interpreted to be the extrusive 

equivalent of subvolcanic rhyolite intrusions associated with 

Moonlight-Kings River-type uranium deposits.

Favorable Stratigraphy for Uranium Deposits

Outside delineated tracts in the study area for the 

Southeastern Oregon and North-Central Nevada Sagebrush Focal 

Area, it is conceivable that additional uranium deposits may 

be identified. Scattered occurrences, geochemical and surface 

radiometric anomalies, identification of permissive strata, and 

delineation of permissive tracts in past assessments support low 

potential throughout the study area for the Southeastern Oregon 

and North-Central Nevada Sagebrush Focal Area.

The Paradise Valley/Capitol Peak area is approximately 

15 km east of the McDermitt Caldera and was identified during 

the U.S. Department of Energy National Uranium Resource 

Evaluation program as favorable for uranium deposits based 

on radiometric and geochemical anomalies associated with a 

thick pile of permissive silicic volcanic rocks (Garside, 1982). 

However, no uranium occurrences or geochemical anomalies 

were confirmed by more recent geochemical and mineral deposit 

compilations, and a tract was not delineated (U.S. Geological 

Survey, 2005; Fernette and others, 2016a; Smith and others, 2016).

Mineral Potential Tract for Orogenic LowSulfide Gold-Quartz Vein Deposits

One mineral potential tract for orogenic low-sulfide goldquartz vein deposits was delineated and rated in this study area: 

tract ONOG01, Orovada.

Tract ONOG01, Orovada—A moderate potential (M), 

with certainty level C, for orogenic gold deposits is assigned 

to metamorphosed siliciclastic rocks of the Triassic Auld Lang 

Syne Group in the study area for the Southern Oregon and 

North-Central Nevada Sagebrush Focal Area (tract ONOG01, 

Orovada; fig. 23C; appendix 2). The tract includes the Orovada 

active exploration project (Fernette and others, 2016a) and 

extends into the proposed withdrawal area and the Nevada 

additions study area.

Orogenic gold veins form during metamorphic dewatering of 

siliciclastic sequences where ascending fluids cool and decompress 

in dilatant structures (Groves and others, 1998; Phillips and 

Powell, 2010). Such veins are present in metamorphosed Auld 

Lang Syne Group, part of the Jungo terrane, which was emplaced 

along the Fencemaker thrust fault and heated by Cretaceous 

granitic intrusions (Cheong and others, 2000). The tract consists 

of map units that comprise the Jungo terrane (Trs; fig. 19) and 

includes a 1-km-wide buffer to account for cover and uncertainty 

of mapped contacts.

Production of gold or other commodities was not 

recorded in the tract; 19 prospects and occurrences in the 

tract contain variable amounts of gold, silver, antimony, 

and base metals (Cheong and others, 2000; U.S. Geological 
80 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Survey, 2005; Johnston and others, 2015; Fernette and 

others, 2016a). Placer gold, possibly derived from orogenic 

gold veins, is reported in two drainages on the west side 

of this tract (Fernette and others, 2016a). Anomalous 

concentrations of gold and arsenic are present in stream 

sediments (Day and others, 2016; Smith and others 2016). 

The tract includes active lode claims, closed plans of 

operations and notices (fig. 20; tables 10, 11, 12, 13), and 

historic claims (fig. 21; Causey, 2007, 2011).

Market Analyses of Gold, Silver, Mercury, 

Gallium, and Uranium

Market analyses of gold, silver, mercury, gallium, and 

uranium are provided in appendix 5 and section I of Day and 

others (2016). 

Mineral Potential Tract for Gemstone Deposits

One mineral potential tract for gemstone deposits 

was delineated and rated in the study area: tract ONAG01, 

McDermitt Gemstones.

Tract ONAG01, McDermitt Gemstones—A high 

potential (H), with certainty level D, for semiprecious 

gemstone deposits is assigned to caldera-fill sediments in 

the northern part of the McDermitt caldera (tract ONAG01, 

McDermitt Gemstones; fig. 23D; appendix 2). Eight 

occurrences of agate, picture stone, wonderstone (decorative 

and ornamental rocks), petrified wood, and geodes have 

historical production, and seven prospects are in the study 

area. The agate is termed and marketed as Purple Cow 

agate. Green jasper in petrified wood has been marketed as 

larsonite. McDermitt picture stone is marketed in slabs and 

in jewelry. Detailed descriptions of the mine sites that have 

historical production and continue to produce semiprecious 

gemstones, picture rock, and petrified wood are provided by 

Kappele (2011).

Mineral Potential Tracts for Hectorite (LithiumRich Clay) Deposits

Two mineral potential tracts for hectorite (lithium-rich 

clay) deposits were delineated and rated in the study area: 

tract ONLI01, West Lith; and tract ONLI02, Whitehorse 

Lithium.

Tract ONLI01, West Lith—A high potential (H), with 

certainty level D, for deposits of lithium-bearing hectorite 

clay is in the West Lithium tract, defined by the distribution 

of sedimentary rocks and water-laid tuffs that fill the moat of 

the McDermitt Caldera (tract ONLI01, West Lith; fig. 23E; 

appendix 2). The McDermitt caldera is among the world’s most 

highly mineralized calderas and contains significant deposits 

of lithium in hectorite and illite clays. This lithium resource is 

potentially critical to the United States development of clean 

energy economy as defined in the American Recovery and 

Reinvestment Act (The White House, 2016). The stratiform 

lithium deposits and lithium-mineralized sedimentary rocks 

occur in caldera-fill sedimentary rocks that have been altered to 

zeolites and adularia (Glanzman and others, 1977; Glanzman 

and Rytuba, 1979; Eggleston, 2008). The highest concentrations 

of lithium occur in trioctahedral illite clays, and lower lithium 

concentrations occur in overlying trioctahedral and dioctahedral 

smectite clays (Glanzman and Rytuba, 1979; Stillings, 

2012). Observed factors that contribute to the high potential 

designation include the presence of five distinct lithium deposits 

that have been discovered in the past decade by Western 

Lithium. One deposit has been proposed for development; 

it contains 234 million short tons at a grade of 0.665 percent 

lithium (570 kilotons lithium carbonate equivalent, Eggleston, 

2008; Tetra Tech, 2014). More than 40 drill holes throughout the 

caldera have encountered lithium-mineralized rocks in calderafill sedimentary rocks at grades that are potentially economic 

(Tetra Tech, 2014). In addition, geochemical anomalies and 

mineralogical studies reported by Glanzman and others 

(1977), Rytuba and Glanzman (1979), and Stillings (2012) 

demonstrate that there are occurrences of lithium-mineralized 

rocks throughout the caldera-fill sedimentary rocks. The 

cumulative lithium resource in the caldera is comparable to the 

similar Sonora Lithium clay deposit in Mexico being developed 

by Bacanora and Rare Earth Minerals. Production from this 

deposit has recently been contracted by Tesla Motors to supply 

lithium for its lithium battery gigafactory in Reno, Nevada (The 

Northern Miner, 2015).

Tract ONLI02, Whitehorse Lithium—The caldera-fill 

sediments in the Whitehorse caldera have moderate potential (M), 

with certainty level B, for deposits of lithium-bearing hectorite 

clay (tract ONLI02, Whitehorse Lithium; fig. 23E; appendix 2). 

The tract boundary is defined mainly by the Whitehorse caldera 

margin, but extends beyond the southwest caldera margin to 

include sedimentary rocks (Tts) deposited within a structural basin 

that may represent an older caldera (Rytuba and others, 1981; 

Rytuba and others, 1982b; Barrow, 1983). The tract includes 

sedimentary rocks, water-laid tuffs, and diatomite of the Trout 

Creek Formation of Smith, 1927 (his unit Ttc) within the caldera 

and areas where the rocks are covered by younger basalt flows and 

alluvium (Rytuba and others, 1982a,b,c,d,e,f). 

The Whitehorse caldera has similar geochemistry to the 

nearby McDermitt caldera that contains a large resource of 

lithium-rich hectorite clay. Evidence for lithium resources 

in Whitehorse caldera stratigraphy includes limited surface 

geochemical samples that are anomalous in lithium and clays 

within the caldera-fill sedimentary rocks that have been documented by X-ray diffraction and scanning electron microscope 

studies of two drill holes (Rytuba and others, 1981).
Mineral-Resource Potential 81

Mineral Potential Tracts for Specialty Clay 

Deposits

Two mineral potential tracts for specialty clay deposits 

were delineated and rated in the study area: tract ONCL01, 

Colloid; and tract ONCL02, Whitehorse Clay. 

Tract ONCL01, Colloid—There is high potential (H), 

with certainty level D, for deposits of specialty clay, used 

primarily in cosmetics, in the Colloid tract, which is defined 

by the distribution of sedimentary and volcanic rocks that fill 

the moat of the McDermitt Caldera (tract ONCL01, Colloid; 

fig. 23F; appendix 2). This tract is spatially coincident with 

tract ONLI01, West Lith. Observed factors that contribute 

to the high potential designation include the presence of two 

clay mines that operate intermittently. J.M. Huber Corporation 

mines clays for specialty use and American Colloid has 

mined hectorite clay in the area known as the Huber open 

pit for the past 25 years (Odom, 1992; Tetra Tech, 2014). In 

addition, X-ray diffraction studies (Rytuba and others, 2003) 

demonstrate the widespread occurrence of clay minerals in the 

caldera-filling sedimentary rocks.

Tract ONCL02, Whitehorse Clay—The caldera-fill 

sedimentary rocks of the Whitehorse caldera have moderate 

potential (M) with certainty level B for deposits of specialty 

clay (tract ONCL02, Whitehorse Clay; fig. 23F; appendix 2). 

Delineation of tract boundaries and tract geology are described 

in report section “Tract ONLI02, Whitehorse Lithium.” 

The Whitehorse caldera contains sedimentary rocks 

similar to sedimentary rocks in the nearby McDermitt caldera 

that contains a large resource of specialty clay (tract ONCL01, 

Colloid, above). Evidence for specialty clay resources in 

Whitehorse caldera stratigraphy includes clays within the 

caldera-fill sedimentary rocks that are documented by X-ray 

diffraction and scanning electron microscope studies of two 

drill holes (Rytuba and others, 1981).

Mineral Potential Tracts for Zeolite Deposits

Two mineral potential tracts for zeolite deposits were 

delineated and rated in the study area: tract ONZE01, Nor 

Zeo; and tract ONZE02, Whitehorse Zeolite. 

Tract ONZE01, Nor Zeo—There is high potential (H), with 

certainty level D, for zeolite deposits in caldera-fill sediments 

that occur in the northern part of the McDermitt Caldera (tract 

ONZE01, Nor Zeo; fig. 23F; appendix 2). Zeolites are present 

throughout the northern part of the caldera-fill sedimentary rocks. 

The distribution of zeolites that consist of clinoptilolite, mordenite, 

and analcime was studied by X-ray diffraction methods and was 

delineated by Glanzman and Rytuba (1979) and Rytuba and others 

(2003). The zeolites formed by hydrothermal and diagenetic 

alteration of the caldera-fill sediments. In the southwestern part 

of the caldera, the sedimentary rocks are altered to alkali feldspar 

rather than zeolites. The area of caldera-fill sedimentary rocks 

that contains feldspar instead of zeolites was delineated by the 

X-ray diffraction studies reported by Rytuba and others (2003) 

and these areas were excluded from the tract. The boundary 

between potassium-rich and potassium-poor sedimentary rocks is 

also demonstrated with geochemical studies and by a radiometric 

survey (U.S. Geological Survey, 1982).

Tract ONZE02, Whitehorse Zeolite—The caldera-fill 

sedimentary rocks of the Whitehorse Caldera have moderate 

potential (M), with certainty level C, for zeolite deposits 

(tract ONZE02, Whitehorse Zeolite; fig. 23G; appendix 2). 

Delineation of tract boundaries and tract geology are described 

in report section “Tract ONLI02, Whitehorse Lithium.” 

The Whitehorse caldera contains sedimentary rocks similar 

to those in the nearby McDermitt caldera that are altered to 

zeolites. The zeolites formed from the alteration of water-laid tuffs. 

X-ray diffraction and scanning electron microscope studies of two 

drill holes in the Whitehorse caldera demonstrate the presence 

of anomalous amounts of the zeolites clinoptilolite, phillipsite, 

and erionite in caldera-fill sedimentary rocks (Rytuba and others, 

1981). Clays are associated with the zeolites (see report section 

“Tract ONCL02, Whitehorse Clay”).

Mineral Potential Tracts for Lacustrine 

Diatomite Deposits 

Two mineral potential tracts for lacustrine diatomite deposits 

were delineated and rated in the study area: tract ONDT01, 

Whitehorse Diatomite; and tract ONDT02, Harney-Malheur, 

which is based on favorable stratigraphy.

Tract ONDT01, Whitehorse Diatomite—This tract has 

moderate potential (M) for lacustrine diatomite deposits at 

certainty level C (tract ONDT01, Whitehorse Diatomite; fig.23H; 

appendix 2). The tract is located in eastern Harney County, 

Oregon, where it is delineated by the mapped extent of the Trout 

Creek Formation (Barrow, 1983), a lacustrine basin-fill unit 

generally within the Whitehorse caldera, a feature recognized 

by negative gravity and aeromagnetic anomalies (Rytuba and 

others, 1981). The host unit is delineated as the composited map 

extent of the Trout Creek Formation of Smith (1927; his unit Ttc, 

undivided) and subunits Ttcb (basalt unit), Ttcd (diatomaceous 

unit), and Ttct (tuffaceous unit), and was generated from the 

scanned, georeferenced, and digitized map of Barrow (1983). The 

unit spatially corresponds in part to unit Tts from the Oregon state 

map (Miller and others, 2002; geology from Walker and MacLeod, 

1991) and unit Tts (Walker and Repenning, 1965) that includes the 

Trout Creek Formation and Virgin Valley Beds.

The diatomite potential from a previous mineral 

assessment conducted in the vicinity of the tract was moderate 

with B certainty (U.S. Geological Survey and U.S. Bureau 

of Mines, 1989). Although current and past production was 

not recorded, two point locations within the tract are noted 
82 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

as the “Trout Creek Diatomite Occurrence” and the “Trout 

Creek West Deposit” (U.S. Geological Survey, 2016a). Total 

thickness of the Trout Creek Formation in the caldera is about 

183 m, with diatomaceous earth being the upper 37 m (Rytuba 

and others, 1981; Bawiec and others, 1989).

Tract ONDT02, Harney-Malheur—This tract has low 

potential (L) for lacustrine diatomite deposits at certainty level 

B (tract ONDT02, Harney-Malheur; fig. 23H; appendix 2). 

It is in eastern Harney and Malheur Counties, Oregon, and 

consists of Pliocene and Miocene stratigraphic units Ts and Ts? 

(Walker and MacLeod, 1991) on the Oregon state map (Miller 

and others, 2002); these units include diatomite as a minor or 

incidental lithology among sedimentary units associated with 

volcanic strata.

More specifically, the geologic units represented by 

unit Ts in Oregon are semiconsolidated to well-consolidated, 

mostly lacustrine tuffaceous sandstone, and siltstone, 

mudstone, concretionary claystone, pumicite, diatomite, 

air-fall and water-deposited vitric ash, palagonitic tuff, and 

tuff breccia, and fluvial sandstone and conglomerate (Walker 

and MacLeod, 1991). The Harney County portion of the tract 

was deposited in the Pueblo caldera in which the lower part 

of the caldera fill consists of thin beds of diatomaceous earth 

interstratified with tuffaceous sedimentary rocks and thin 

pyroclastic flows (Bawiec and others, 1989). Elsewhere in 

Harney and Malheur Counties, Walker and Repenning (1965; 

1966) show additional mapped units Pleistocene to Pliocene 

unit QTs, Pliocene unit Tst, and Miocene unit Tts as tuffaceous 

lacustrine sediments containing “ashy diatomite,” although the 

Oregon state map (Miller and others, 2002) does not mention 

diatomite in this unit. These units were not included in the 

tract because of their implied impure nature.

The diatomite potential from a previous mineral assessment 

conducted in the vicinity of the Harney County portion of the 

tract was low and of B certainty (U.S. Geological Survey and 

U.S. Bureau of Mines, 1989). No current or past mines, no 

identified prospects or occurrences, and no active claims, plans of 

operations, or notices are within the tract.

Market Analyses of Lithium, Zeolites, and 

Diatomite

Market analyses of lithium, zeolite, and diatomite are 

provided in appendix 5 and section I of Day and others (2016).

Occurrence of Leasable Minerals

Leasable mineral commodities (leasable solid and fluid 

minerals) include oil and gas, geothermal, coal, and nonenergy solid minerals, including phosphate and potash. These 

commodities were not evaluated for assessment, but were 

qualitatively appraised for exploration and mining activity, 

lease status, and potential for deposits within the study area 

for the Southern Oregon and North-Central Nevada Sagebrush 

Focal Area. No production of leasable solid minerals (coal, 

phosphate, and potash) or production of leasable fluid 

minerals (oil and gas, and geothermal) has occurred in the 

study area. Favorable stratigraphy for coal and phosphate is 

not exposed, has not been recognized, or is concealed within 

the study area. Based on comparison to deposits of these 

commodities elsewhere in the western United States with 

past or present production (including oil and gas fields, and 

geothermal fields), and current market conditions, neither 

concealed or exposed deposits of these commodities are likely 

to be explored for, or produced, in coming decades, with the 

possible exceptions of geothermal and potash.

Although no oil and gas, geothermal, and potash have been 

produced, these commodities occur, and have been explored 

for under leases in the study area for the Southern Oregon 

and North-Central Nevada Sagebrush Focal Area. Although all 

leases are closed, they indicate that exploration for these leasable 

commodities has occurred in recent years (table 10). 

Oil and Gas

There are 135 closed oil and gas leases in the study area 

for the Southern Oregon and North-Central Nevada Sagebrush 

Focal Area (table 10). One dry well is within the USGS study 

area boundary but external to the proposed withdrawal area 

(fig.24). Oil and gas exploration, assessment, and potential 

in the four study areas are described in report section 

“Introduction; Leasable Minerals.” 

Geothermal 

There are 29 closed geothermal leases in the study area 

for the Southern Oregon and North-Central Nevada Sagebrush 

Focal Area (fig. 24; table 10). Geothermal exploration, 

assessment, and potential in the four study areas are described 

in report section “Introduction; Leasable Minerals.” 

Potash

No potash occurrences are in the study area for the 

Southern Oregon and North-Central Nevada Sagebrush 

Focal Area. However, 8 leases for non-energy, solid mineral 

commodities were recorded by the BLM; all are closed (table 

10). The leases are situated near the former Lake Lahonton 

high-stand shoreline (fig. 24), suggesting that lacustrine basin 

brine containing potassium salts may have been the commodity 

sought. An important source of potash salt production in the 

western United States is brine in intracontinental, closed basins 

(Orris, 2011). Closed basins have restricted surface water inflow 

and outflow. Lowland basins and adjacent mountain ranges in 
Mineral-Resource Potential 83

the Basin and Range Province comprise physiography in which 

closed-basin lakes could form and brines could subsequently 

evolve. During the Pleistocene, at least two large, closed-basin 

lakes, Lake Bonneville and Lake Lahontan, formed in the Basin 

and Range. As Lake Bonneville water levels steadily declined 

from the high stand at about 15,000 years before present to the 

Holocene, lake water salinity and potash salt concentrations 

increased. 

Near Wendover, Utah, south of the study area for the 

Southern Idaho and Northern Nevada Sagebrush Focal Area, 

groundwater that is a remnant of Lake Bonneville is pumped from 

shallow groundwater wells and evaporated in solar evaporation 

ponds; precipitates are processed to recover potash and other salts. 

No producing closed-basin brine potash occurrences are known in 

the study areas to the west that are partially cospatial with former 

Lake Lahonton. South of the study area for the Sheldon-Hart 

Mountain National Wildlife Refuge Complex Sagebrush Focal 

Area, closed basin potash brine occurrences in Churchill County, 

Nevada (Dixie and North Sand Springs Marshes), in part coincide 

with the former extent Lake Lahontan (Papke, 1976). A potash 

tract was delineated that coincides with former Lake Bonneville, 

but a potash tract was not delineated for former Lake Lahontan 

(Orris and others, 2014).

Occurrence of Salable Minerals

Salable mineral commodities, mainly sand and gravel, and 

aggregate, have been produced at numerous sites in the study area 

for the Southern Oregon and North-Central Nevada study area. 

There are 104 salable commodity sites (mineral materials sales 

sites) in the study area, 17 of which are authorized (approved) and 

pending, and 87 of which are closed or expired (fig. 25; table 10). 

There are 7 approved (authorized) sites that are sand and gravel, 2 

are soil/topsoil, 4 are crushed stone, 2 are specialty stone, and 2 are 

weathered granite (table 15). 

Table 15. Active mineral material sales sites in the proposed withdrawal area within 

the study area for the Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Area, Nevada and Oregon.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey 

System (PLSS) section that includes a proposed withdrawal area]

Commodity Number of approved sites Number of pending sites

Sand and gravel 7 0

Soil/other, topsoil 2 0

Stone, crushed and broken 4 0

Stone, specialty 2 0

Stone, weathered granite 2 0
84 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

S

Nevada additions

Figure 24. Map showing Bureau of Land Management (BLM) oil and gas, geothermal, and potash leases; oil and gas exploration (dry); 

and geothermal sites in the study area for the Southeastern Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and 

Oregon (Williams and others, 2008a,b; Dicken and San Juan, 2016; Gunther and others 2016a,b; IHS Energy Group, 2016). USGS, U.S. 

Geological Survey.
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ELKO

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 areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH

NEVADA

WASHINGTON

Southern Idaho and

Northern Nevada 

Study Area

BLM—Leasable Commodities

EXPLANATION

Geothermal; closed

Oil and gas; closed

Non energy: eommodity; ease disposition 

Potash, potassium; closed, rejected

Geothermal sites

Oil and gas exploration (dry)

Oil and gas exploration

Base data

USGS study area boundary

Proposed withdrawal areas

Proposed withdrawal additions

State boundaries

County boundaries

Energy: commodity; case disposition

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Geothermal developing sites 9/02/14

USGS low-temperature systems

USGS moderate- and high-temperature systems

Geothermal operating sites 10/26/15

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Mineral-Resource Potential 85

Figure 24.—Continued
86 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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COUNTY

HARNEY

COUNTY

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COUNTY

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119°00' 118°00' 117°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

S

Nevada additions

Figure 25. Map showing Bureau of Land Management (BLM) salable mineral commodity sites in the study area for the Southeastern 

Oregon and North-Central Nevada Sagebrush Focal Area, Nevada and Oregon (Dicken and San Juan, 2016). USGS, U.S. Geological 

Survey.
OWYHEE

COUNTY

ELKO

COUNTY

IDAHO

116°00'

Map

area

Study

 areas

IDAHO

MONTANA

OREGON

WYOMING

UTAH

NEVADA

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

Proposed withdrawal additions

State boundaries

County boundaries

Southern Idaho and

Northern Nevada 

Study Area

Stone (specialty, weathered, riprap, crushed, dimension);

 authorized

Stone (specialty, weathered, riprap, crushed, dimension);

 closed, expired

Clay, common; authorized

Clay, common; closed

Gemstone; authorized, closed expired, pending, withdrawn

Sand and gravel; authorized, pending

Sand and gravel; closed, expired, rejected

To be defined, none; closed

EXPLANATION

BLM—Salable mineral commodities: commodity; case disposition

Mineral-Resource Potential 87

Figure 25.—Continued

Mineral-Resource Potential of the Study Area for the 

Southern Idaho and Northern Nevada Sagebrush Focal 

Area, Nevada, Idaho, and Utah

Introduction

The study area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area spans the borders of Idaho, Nevada, and 

Utah, and includes parts of Cassia, Owyhee, and Twin Falls 

Counties, Idaho; Elko County, Nevada; and Box Elder County, 

Utah (fig. 26). This report section describes the mineral potential 

of the proposed withdrawal area within the study area for the 

Southern Idaho and Northern Nevada Sagebrush Focal Area, 

which includes parts of the proposed withdrawal area described 

in report section “Introduction.” The proposed withdrawal area 

within this study area encompasses 3,734,263 acres (~15,112 km2

; 

5,835 mi2), of which, the Bureau of Land Management (BLM) 

manages 3,343,220 acres and the U.S. Forest Service manages 

390,933 acres. 

Description of Geology

Archean, Neoproterozoic, Paleozoic, Mesozoic, Tertiary, 

and Quaternary rocks are exposed within the proposed 

withdrawal area within the study area for the Southern Idaho 

and Northern Nevada Sagebrush Focal Area, Idaho, Nevada, 

and Utah, and the USGS study area boundary (fig. 27). Most 

pre-Tertiary rocks within the USGS study area boundary are 

in Nevada and Utah, whereas the USGS study area boundary 

in Idaho nearly entirely encloses Tertiary strata. Archean, 

Neoproterozoic, and Paleozoic rocks include metamorphosed 

igneous and sedimentary rocks. Paleozoic sedimentary rocks 

(Cambrian to Permian) comprise the Roberts Mountains and 

Golconda allochthons. These allochthons have been intruded 

by granitic rocks, mostly plutons (Jurassic, Cretaceous, and 

Tertiary). Tertiary strata are predominantly volcanic lava 

flows and tuffs, and sedimentary rocks (Eocene, Miocene, 

and Pliocene). Quaternary strata include volcanic rocks and 

surficial deposits. In Nevada and Utah, the two allochthons 

have been juxtaposed by compressional tectonism during the 

Mesozoic. The allochthons and Tertiary volcanic strata have 

been laterally displaced by late Tertiary extensional tectonism 

which produced the modern landforms of alternating, northsouth oriented mountain ranges separated by broad, relatively 

flat valleys (Basin and Range topography). In Idaho, exposed 

Miocene and Pliocene strata are part of a sequence of mostly 

rhyolite, basalt, and lacustrine rocks that fill a large, arcuate 

depression, the Snake River Plain, which spans the southern 

part of Idaho, southeastern Oregon, and northwestern 

Wyoming. These Tertiary strata form broad volcanic uplands 

across the northern and western parts of the study area.

More complete descriptions of these strata, and their 

tectonic evolution, are in report section “Introduction; 

Description of Geology.”

Mineral-Resource Potential

Mineral Deposit Types

Characteristics of metallic and nonmetallic locatable 

mineral deposits, prospects, and host rocks in the study area 

for the Southern Idaho and Northern Nevada Sagebrush Focal 

Area, Idaho, Nevada, and Utah (appendix 2), are compatible 

with classification of these deposits as numerous deposit types, 

including epithermal gold and silver deposits, hydroallogenic 

uranium deposits, various intrusion-related deposits, volcanogenic 

massive sulfide (VMS) deposits, Carlin-type gold deposits, 

lacustrine diatomite deposits, and bedded barite deposits. Within 

the study area there is also favorable or permissive stratigraphy 

for several of these deposit types (volcanogenic massive sulfide, 

Carlin-type gold, lacustrine diatomite, and bedded barite deposits) 

and for black shale vanadium deposits, sedimentary exhalative 

(SEDEX) zinc-lead-silver-gold deposits, and Mississippi Valleytype (MVT) lead and zinc deposits (Day and others, 2016).

Epithermal gold, silver, and mercury deposits are 

shallowly formed vein, stockwork, disseminated, and 

replacement deposits that are mined primarily for gold and 

silver. Hot-spring-type mercury deposits are often the nearsurface expression of gold and silver deposits that occur at 

deeper levels below mercury-enriched sinter and volcaniclastic 

strata. Epithermal gold, silver, and mercury deposits in the 

western United States occur largely in Eocene-Miocene 

volcanic fields and have been mined primarily for gold and 

silver, and lesser mercury (on the basis of mass and value).

Hydroallogenic uranium deposits are localized primarily 

by permeability and paleohydrology. They occur in a wide 

variety of rock types, including granitic and sedimentary 

rocks. Uranium in these largely Tertiary deposits is derived 

from low-temperature fluid leaching of volcanic rocks, often 

proximal to deposits, and is concentrated by fluid reduction in 

faults, shear zones, joints, and permeable strata. 
90 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

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ELMORE

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OWYHEE

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COUNTY

ELKO

COUNTY

HUMBOLDT

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117° 116° 115° 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 26. Map showing proposed withdrawal areas that comprise the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Nevada, Idaho, and Utah, and boundary of the U.S. Geological Survey (USGS) study area. The study area boundary corresponds to 

townships that enclose the proposed withdrawal areas. 
Twin Falls

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CASSIA

COUNTY

JEROME

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LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°

Map

area Study areas

IDAHO

MONTANA

OREGON WYOMING

NEVADA UTAH

WASHINGTON

EXPLANATION

Base data

USGS study area boundary

Proposed withdrawal areas

State boundaries

County boundaries

Proposed withdrawal additions

USGS study area boundary

(North-Central Idaho Study Area)

Figure 26.—Continued

Mineral-Resource Potential 91
92 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

117° 116° 115° 

42°30'

41°30'

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

HUMBOLDT

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Base modified from U.S. Geological Survey DEM data, 2016.

Political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Figure 27. Simplified geologic map of the study areas for the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Nevada, Idaho, and Utah; and the Nevada additions. Synthesized from Hintze and others (2000), Crafford (2007), and Lewis and 

others (2012). USGS, U.S. Geological Survey.
114°

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

S

ELKO

COUNTY

BOX ELDER

COUNTY

UTAH

Map

area Study areas

IDAHO

MONTANA

OREGON WYOMING

NEVADA UTAH

WASHINGTON

EXPLANATION

Base data

USGS study area boundary

State boundaries

Golconda allochton (Permian to Mississippian)

Intrusive rocks (Tertiary)

Mafic to intermediate lava flows (Pliocene and Miocene)

Mesozoic granitic rocks (Cretaceous and Jurassic)

Metamorphic rocks (Paleozoic and Neoproterozoic)

Precambrian basement (Proterozoic and Archean)

Rhyolite tuffs and lava flows (Pliocene and Miocene)

Roberts Mountains allochthon (Devonian to Cambrian)

Sedimentary rocks (Pliocene and Miocene)

Sedimentary rocks of the North American

 continental shelf (Triassic to Cambrian)

Surficial deposits (Quaternary)

Volcanic and sedimentary rocks (early Miocene to Eocene)

Volcanic rocks (Quaternary)

Generalized lihologic units (geologic age)

Water body

County boundaries

USGS study area boundary

(North-Central Idaho Study Area)

Figure 27.—Continued

Mineral-Resource Potential 93
94 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Numerous intrusion-related deposit types are represented 

in the study area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area, including porphyry copper, 

porphyry molybdenum, copper skarn, tungsten skarn, leadzinc skarn, polymetallic replacement, polymetallic vein, and 

distal disseminated silver-gold deposits. Porphyry copper and 

molybdenum deposits consist of copper minerals (mainly 

chalcopyrite) and molybdenite that are disseminated in highly 

altered, granitic and porphyritic, mostly felsic intrusions, and 

occur in veins and breccias in and adjacent to these intrusions. 

Most deposits are Mesozoic and Cenozoic, and many deposits, 

because of the large scale of mining, produce annually, in addition 

to copper and molybdenum, hundreds of thousands to millions of 

ounces of gold and silver. Copper, tungsten, and lead-zinc skarn 

and polymetallic replacement and vein deposits consist of copper, 

tungsten, lead, zinc, silver, gold, and numerous silicate, carbonate, 

oxide, sulfide, and sulfate minerals that have replaced, or comprise 

veins in, carbonate and lesser siliciclastic rocks adjacent to, 

proximal to, and distal to granitic and porphyritic, mostly felsic 

intrusions. In addition to copper, tungsten, lead, and zinc, silver 

and gold commonly have been recovered from these deposits, 

may have been the main commodity recovered, or, because of 

high unit value, may have enabled recovery of other metals. Some 

skarn, replacement, and vein deposits are adjacent to intrusions 

containing porphyry copper and molybdenum deposits. Distal 

disseminated silver-gold deposits occur mainly in carbonate and 

clastic sedimentary rocks distal to porphyry copper, skarn, and 

polymetallic vein deposits, and have been mined nearly entirely 

for silver and gold. 

Volcanogenic massive sulfide (VMS) deposits, from 

which copper and lesser zinc and silver are produced, consist 

of stratabound concentrations of sulfide minerals that were 

precipitated from hydrothermal fluids in extensional seafloor 

environments. These mostly Paleozoic and Mesozoic deposits 

are interbedded with basaltic to andesitic sills and flows, and 

siliciclastic rocks.

Carlin-type gold deposits consist of gold-bearing pyrite 

disseminated in Paleozoic marine, carbonaceous, calcareous, 

and (or) dolomitic sedimentary rocks which were deposited on 

slopes of the carbonate platform margin, or in marginal basin, 

shelf, foreland basin, and overlap sequences. These mostly 

Eocene deposits predominantly occur in the Great Basin of 

Nevada and compose a major crustal supply of gold.

Lacustrine diatomite deposits consist of chalklike, earthy 

siliceous sedimentary strata composed of diatoms. In volcanic 

terranes, diatomaceous lake sediments typically occur within 

sequences of volcanic and sedimentary rocks. Lacustrine 

diatomite deposits in the western United States occur primarily 

in high-silica sequences of middle Miocene flows and tuffs.

Bedded barite deposits are meters-thick, stratiform masses 

of barite and barite-rich strata that have lateral dimensions 

of as large as several kilometers. They form by precipitation 

from fluids vented in submarine basins and form beds or lenses 

within carbonate and siliciclastic sequences. In the Great Basin 

of the western United States, bedded barite deposits occur in 

middle to late Paleozoic rocks.

Geology and Occurrence of Mineral Deposit 

Types

The southeastern and eastern parts of the study area for 

the Southern Idaho and Northern Nevada Sagebrush Focal 

Area, Idaho, Nevada, and Utah, are underlain by Paleozoic 

and Mesozoic sedimentary and granitic rocks, and lower 

Paleozoic, Neoproterozoic, and older Precambrian siliciclastic 

and metamorphic rocks. These rocks are covered, in part, 

by Tertiary and Quaternary volcanic and sedimentary rocks. 

The Mesozoic granitic rocks have intruded Paleozoic and 

Mesozoic carbonate and siliciclastic strata of the North 

American continental shelf, the Roberts Mountains allochthon, 

and Precambrian rocks. The northern and western parts of 

the study area are underlain nearly entirely by Tertiary and 

Quaternary volcanic and sedimentary rocks (fig. 27).

Epithermal gold and silver deposits and lacustrine 

diatomite deposits occur in Tertiary volcanic flows, intrusions, 

tuffs, and associated epiclastic sedimentary strata in Elko 

County, Nevada, and Owyhee and Cassia Counties, Idaho. 

Most epithermal gold and silver deposits are in Elko 

County, Nevada, in the southeastern part of the study area. 

Hydroallogenic uranium deposits, intrusion-related deposits, 

VMS deposits, Carlin-type gold deposits, and bedded barite 

deposits occur mainly in pre-Tertiary sedimentary and igneous 

rocks and nearly all deposits are in in Elko County, Nevada, in 

the southeastern part of the study area. Favorable pre-Tertiary 

stratigraphy for volcanogenic massive sulfide deposits, 

Carlin-type gold deposits, bedded barite deposits, black shale 

vanadium deposits, SEDEX zinc-lead-silver-gold deposits, 

and MVT lead and zinc deposits is also exposed primarily in 

the southeastern part of the study area. Favorable stratigraphy 

for lacustrine diatomite deposits spans most of the study area.

Exploration and Mining Activity for Locatable 

Minerals

Metallic and nonmetal locatable mineral commodities 

that have been mined and explored for in the study area 

for the Southern Idaho and Northern Nevada Sagebrush 

Focal Area include gold, silver, copper, lead, zinc, uranium, 

antimony, tungsten, diatomite, and barite. Large numbers 

(thousands) of lode and placer claims have been staked 

in the study area (fig. 28, 29, 30; tables 16, 17); there are 

30 authorized, pending, approved, and proposed plans of 

operations and notices for gold, silver, tungsten, diatomite, 

and an unspecified commodity, and 101 closed and expired 

plans of operations and notices in the study area, indicative 

of current and recent mineral exploration (fig. 28; tables 18, 

19). In addition, numerous claims were staked and filed in the 

study area from 1976 to 2007 (Causey, 2007, 2011; fig. 29).

Several epithermal gold and silver deposits, various types 

of intrusion-related deposits, several hydroallogenic uranium 

deposits, one VMS deposit, and bedded barite deposits with 

recorded production exist within, or partially within the study area 
Mineral-Resource Potential 95

(table 20). Production from epithermal gold and silver deposits in 

the Jarbidge district (Elko County, Nevada) was about 0.36 million 

troy ounces (Moz) of gold and 1.67 Moz of silver. Production 

from epithermal gold and silver deposits in the Good Hope and 

Cornucopia districts (Elko County, Nevada) was about 0.10 Moz 

of gold and 0.76 Moz of silver. Gold and silver produced from 

intrusion-related, polymetallic deposits in the six largest districts 

in the study area (Island Mountain, Edgemont, Delano, Mountain 

City, Contact, and Charleston districts, Elko County, Nevada) 

total 64,390 troy ounces (oz) of gold and 5,840,616 oz of silver. 

The Carlin-type gold deposit at the Big Springs Mine produced 

about 0.4 Moz of gold. Total gold and silver production from these 

districts is about 0.53 Moz and 8.2Moz, respectively. Other metals 

produced from these districts include 104,954 short tons of copper, 

12,232 short tons of lead, 746 short tons of zinc, 27 short tons 

of antimony, and 971 units of tungsten trioxide (WO3). Uranium 

mines in the Mountain City district cumulatively produced about 

20,876 pounds (lbs) of triuranium octoxide (U3O8) (table 20).

Mining districts and exploration projects with gold and silver 

resources that are within or partially within the study area include 

Island Mountain (Elko County, Nevada; 26.3 million short tons at 

0.019 troy ounce per short ton gold), Doby George (Elko County, 

Nevada; 27.1 million short tons at 0.028 opt gold), Aura (Elko 

County, Nevada; 2 million short tons at 0.01 opt gold, 2.2 opt 

silver), White Rock (Elko County, Nevada and Box Elder County, 

Utah; 9 million short tons at 0.018 opt gold), Gravel Creek (Elko 

County, Nevada; 16.9 million short tons at 0.08 opt gold, 1.2 opt 

silver), Wood Gulch (Elko County, Nevada; 0.8 million short 

tons at 0.12 opt gold), Big Springs (Elko County, Nevada; 14.8 

million metric tons at 0.05 opt gold), and Blue Hill Creek (Cassia 

County, Oregon; 14.4 million short tons at 0.016 opt gold). These 

resources contain about 3.5 Moz of gold and about 25 Moz of 

silver (table20). 

Uranium resources include Race Track, Rim Rock, and 

South Fork-Pixley (Elko County, Nevada; cumulative resources 

are 1.1 million pounds [Mlbs] U3O8). Copper resources occur at 

Contact (Elko County, Nevada; 473 million short tons at 0.19 

percent copper). Tungsten resources occur at Indian Springs (Elko 

County, Nevada; 18.9 million short tons at 0.17 percent WO3) and 

in the Alder district (Elko County, Nevada; 0.75 million short tons 

at 0.43 percent WO3; table 20).

Although numerous lode and placer claims have been staked 

in the study area in the vicinity of diatomite and barite deposits 

(tables 16, 17, 18), there is only one active plan of operations 

specifically for diatomite (fig. 28; table 19). No diatomite 

production was recorded within the study area. Barite has been 

mined from a number of deposits in the Snake Mountains (Elko 

County, Nevada), and barite has been produced in the Jarbidge 

district (Elko County, Nevada). Cumulative barite production in 

the study area is about 1.01 million short tons (table 20).

A qualitative estimate of past mining activity for locatable 

metallic (and nonmetallic) mineral commodities was made by 

counting mining-related symbols on USGS topographic maps 

that cover the study area (Fernette and others, 2016b). There are 

2,402 mine symbols shown on USGS 7.5-minute topographic 

maps, 350 of which are adits, shafts, or open-pit mines, and 

1,869 are prospect pits. These symbols are commonly associated 

with mining and exploration of locatable minerals and provide a 

broad indication of the extent of past mining activity in the area. 

Other mine symbols include borrow pits, gravel pits, and cinder 

pits, which are commonly associated with production of salable 

minerals.

A second qualitative estimate of past mining activity 

was made by extracting mines and deposits with the statuses 

“producer” and “past producer” from the USGS Mineral 

Resources Data System (MRDS). The MRDS database contains 

434 records of “producer” and (or) “past producer.” These 

producers include 365 deposits mined for metallic minerals, 

13 deposits mined for industrial minerals, 4 deposits mined for 

uranium, and 42 deposits mined mostly for stone, sand, and gravel 

(U.S. Geological Survey, 2005). However, some MRDS records 

may be duplicates. 

Table 16. Type, number, and status of mining claims, leases, mineral material sales sites for salable mineral commodities, and surfacemanagement plans in the proposed withdrawal area within the study area for the Southern Idaho and Northern Nevada Sagebrush 

Focal Area, Idaho, Nevada, and Utah.

[Leasable mineral commodities include coal, geothermal, non-energy solid mineral, oil and gas. Sources: Dicken and San Juan (2016) for Bureau of Land Management 

(BLM) 43 Code of Federal Regulations (CFR) 3809 data; Susan G. Summer Elliott, U.S. Forest Service (USFS), written commun., March 9, 2016, for USFS 36 CFR 228 

Subpart A plans. The number of cases is for the complete Public Land Survey System (PLSS) section that includes a proposed withdrawal area. —, no data]

Type Mineral 

type

Number 

of unique 

cases

Active Authorized/

Approved

Pending/

Proposed Closed Cancelled Expired Rejected Withdrawn

Mining claims Locatable 29,165 3,221 — — 25,944 — — — —

Coal leases Leasable — — — — — — — — —

Geothermal leases Leasable 7 — — 2 5 — — — —

Non-energy solid mineral leases Leasable — — — — — — — — —

Oil and gas leases Leasable 1,029 — 8 2 1,019 — — — —

Mineral materials sales sites Salable 131 — 17 1 111 — 2 — —

Surface-management plans — 131 9 26 4 93 — 8 — —
96 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Table 17. Summary of active and closed mining claims for locatable minerals in Public Land Survey System (PLSS) sections that 

include the proposed withdrawal area within the study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, Idaho, 

Nevada, and Utah.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete PLSS section that includes a proposed withdrawal area]

Area Active lode 

claims

Closed lode 

claims

Active placer 

claims

Closed placer 

claims

Active 

millsites

Closed 

millsites

Sections containing proposed withdrawal area 3,148 24,906 43 869 30 167

Table 18. Status and number of surface-management plans for locatable minerals in the proposed withdrawal area within the study 

area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, Idaho, Nevada, and Utah.

[Sources: Dicken and San Juan (2016) for Bureau of Land Management (BLM) 43 Code of Federal Regulations (CFR) 3809 plans; Susan G. Summer Elliott, U.S. 

Forest Service (USFS), written commun., March 9, 2016, for USFS 36 CFR 228 Subpart A plans. The number of cases is for the complete Public Land Survey 

System (PLSS) section that includes a proposed withdrawal area. —, no data]

Authorization type Number of unique 

cases

Active Authorized/

Approved

Pending/

Proposed Closed Cancelled Expired Rejected Withdrawn

Plans of operations 33 9 2 1 21 — — — —

Notice 98 — 5 — 85 — 8 — —

Table 19. Status and number of active surface-management plans in the 

proposed withdrawal area within the study area for the Southern Idaho 

and Northern Nevada Sagebrush Focal Area, Idaho, Nevada, and Utah, 

summarized by locatable commodity.

[Active includes active, authorized/approved, and pending/proposed from Table 18. Sources: 

Dicken and San Juan (2016) for Bureau of Land Management (BLM) 43 Code of Federal 

Regulations (CFR) 3809 plans; Susan G. Summer Elliott, U.S. Forest Service (USFS), 

written commun., March 9, 2016, for USFS 36 CFR 228 Subpart A plans. The number of 

cases is for the complete Public Land Survey System (PLSS) section that includes a proposed 

withdrawal area. —, no data]

Commodity Active notices Active plans of operations

Gold and silver — 9

Gold 2 0

Gold, lode 3 1

Soil/other, diatomite 0 1

Tungsten, lode and placer 0 1
Mineral-Resource Potential 97

Table 20. Mined deposits with production and resources within, and partially within, the study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, Idaho, Nevada, and Utah.[Data from technical reports, including NI 43-101 documents, are in Fernette and others, 2016a,b. Nevada mining districts are from Tingley (1992). One unit of tungsten = 20 pounds of tungsten trioxide (WO3) or 15.86 

pounds of tungsten (W); est., estimate; g/metric ton, grams per metric ton; ID, Idaho; lbs, pounds; M+I+I, measured plus indicated plus inferred; MST, million short tons; NV, Nevada; opt, troy ounce per short ton; oz, troy 

ounce; ST, short ton; UT, Utah; @, at; %, weight percent; $, U.S. dollars]

Mine/Deposit name Assessment tract name Mining district County, state Commodity Production years Production Resource Notes; source

Jarbidge INEP04, Jarbidge Jarbidge Elko, NV Gold and silver 1910–1950 355,707 oz gold; 1,666,222 

oz silver

— LaPointe and others (1991)

 Alpha Mine Gold and silver 1923–26 $12,512 — Couch and Carpenter (1943) Bluster Gold and silver 1916–1929 $74,374 — Couch and Carpenter (1943) Wildcat Barite 1955–58 2,727 ST — LaPointe and others (1991) Coon Creek Tungsten 1943–1956 608 units WO3 — Stager and Tingley (1988)Buckeye and Ohio INEP10, Good Hope Good Hope Elko, NV Gold and silver 1880–82; 1921 District: $100,000; ~91,000 

oz gold

— Emmons (1910), Knox 

(1970), LaPointe and others (1991)

Antimony 1950 “several thousand pounds” — Lawrence (1963), LaPointe 

and others (1991)

INEP02, Cornucopia Cornucopia Elko, NV Silver and gold Late 1800s 760,000 oz silver; 13,000 

oz gold

— Emmons (1910)

Diamond Jim, 

Rosebud, Gribble

INPR06, Island Mountain Island Mountain Elko, NV Gold, silver, 

lead, zinc, copper, antimony, tungsten

1918–1982 District: 1,520 oz gold; 

120,671 oz silver; 822 ST lead; 42 ST zinc; 5 ST copper; 11 ST antimony; 15 units tungsten

26,300,000 ST 

@ 0.019 opt gold

LaPointe and others (1991), 

Fernette and others (2016a)

Doby George INCT06, Doby George 1 Island Mountain Elko, NV Gold — — 27,100,000 ST 

@ 0.028 opt gold

Davis and others (2006); 

Western Exploration and Development, Ltd. (2008)

Big Springs INCT04, Big Springs 1 Independence 

Mountains

Elko, NV Gold 1987–1993 386,000 oz gold 14.8 million 

metric tons @ 2 g/metric tongold

Anova Metals Limited 

(2016)

Bull Run, Lucky 

Girl

— Edgemont Elko, NV Gold, silver, 

lead, zinc, copper, tungsten

1902–1971 District: 39,121 oz gold; 

90,649 oz silver; 100 ST lead; 2 ST zinc; 1 ST copper; 3 units tungsten

— LaPointe and others (1991)

Burns — Edgemont Elko, NV Tungsten 1953 3 units WO3 — Stager and Tingley (1988)White Rock INEP06, Angel Wing — Elko, NV; Box 

Elder, UT

Gold 2009 — 9,000,000 ST 

@ 0.018 opt gold; ~150,000 oz gold

Goodall (2003), Kehmeier 

(2009)
98 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah Table 20. Mined deposits with production and resources within, and partially within, the study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, Idaho, Nevada, and Utah.—Continued Mine/Deposit name Assessment tract name Mining district County, state Commodity Production years Production Resource Notes; source Gravel Creek INEP03, Wood Gulch

— Elko, NV Gold and silver

—

— 16,940,000 ST 

@ 0.08 opt gold; 1.2 opt silver

Inventory; Fernette and 

others (2016a)

Wood Gulch INEP03, Wood Gulch

— Elko, NV Gold 1988–1990 34,782 oz gold Est. 780,000 ST 

@ 0.12 opt gold

NV NI 43-101 Doby GeorgeWood Gulch-IL Ranch 

Properties April 24, 2008 technical report

Blue Hill Creek INE07, Oakley

— Cassia, ID Gold

—

— 14,400,000 ST 

@ 0.016 opt gold

Fernette and others (2016a)

Cleveland, Delano INPR10, Delano Delano

— Gold, silver, 

lead, zinc, copper

1918–1980 District: 333 oz gold; 

1,499,973 oz silver; 11,069 ST lead; 693 ST zinc; 84 ST copper; 384 units tungsten

— LaPointe and others (1991)

Indian Springs INPR10, Delano Delano Elko, NV Tungsten

—

— 18,900,000 ST 

@ 0.17% WO3

Stager and Tingley (1988), 

LaPointe and others (1991)

Blue Ribbon-Boyce

— Aurum Elko, NV Antimony 1940 7 ST antimony

— Lawrence (1963)

Rio Tinto, Mountain 

Laurel, Silver King

INPR02, Mountain City; 

INMS03, Rio Tinto 2

Mountain City Elko, NV Copper, gold, 

silver, lead

1869–1982 District: 101,984 ST copper; 

20,557 oz gold; 559,561 oz silver; 54 ST lead; <1 ST zinc 

— LaPointe and others (1991)

Race Track, Rim 

Rock, South Fork-Pixley

INHU01, Racetrack Mountain City Uranium 1950s/1960s 20,876 lbs U

O3 8 1,100,000 lbs 

U

O3 8

Drilled resource 1967–1983; 

Bayswater Uranium Corporation (2007); Proffitt and others (1982)

Blue Jacket INPR04, Blue Jacket Aura Elko, NV Gold, silver, 

copper, lead, zinc

—

— 2 MST @ 0.01 

opt gold; 2.2 opt silver; 0.25% copper; 2% lead; 1.8% zinc

Long and others (1998)

Contact INPR09, Contact Contact Elko, NV Copper, gold, 

silver, lead, tungsten

1908–1965 District: 2,876 ST copper; 

1,222 oz gold; 126,901 oz silver; 180 ST lead; 9 ST zinc; 117 units WO3

473,000,000 

ST @ 0.19% copper

LaPointe and others (1991), 

Fernette and others (2016a)
Mineral-Resource Potential 99

Table 20. Mined deposits with production and resources within, and partially within, the study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, Idaho, Nevada, and Utah.—Continued

Mine/Deposit name Assessment tract name Mining district County, state Commodity Production years Production Resource Notes; source

Consolation-Boies, 

Big Ledge, Hunch, Jungle A, Jungle, Little Dry

INBB02, Snake 

Mountains 1

Snake Mountains Elko, NV Barite 1974–1985 District: 1,008,964 ST barite LaPointe and others (1991)

Batholith — Charleston Elko, NV Tungsten 1954–56 452 units WO3 — Stager and Tingley (1988)Prunty — — — Gold, silver, 

copper, lead, antimony, tungsten

— District: 2,177 oz gold; 

2,861 oz silver; 4 ST copper; 7 ST lead; <1 ST zinc; 16 ST antimony 

— LaPointe and others (1991)

Garnet — Alder Elko, NV Tungsten — — 748,000 ST @ 

0.43% WO3

LaPointe and others (1991)

Ashbrook INPR15, Ashbrook Ashbrook Box Elder, UT — — District: 180,000 ST ore; 

3,440,000 oz silver

Gloyn and Krahulec (2006)
100 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 28. Map showing active and closed surface-management plans for locatable minerals in the study area for the Southern 

Idaho and Northern Nevada Sagebrush Focal Area, Nevada and Oregon, including data from the Bureau of Land Management 

(Dicken and San Juan, 2016, 43 Code of Federal Regulations [CFR] 3809 data) and the U.S. Forest Service (Susan G. Summer Elliott, 

U.S. Forest Service [USFS], written commun., March 9, 2016, for USFS 36 CFR 228 Subpart A plans). USGS, U.S. Geological Survey. 
Twin Falls

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CASSIA

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JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

EXPLANATION

BLM—Locatable commodities: commodity; case disposition; case type

Gold, gold lode; authorized, pending; surface management-notice

Gold lode; pending; surface management-plan

Gold, gold lode, gold placer, copper; closed, expired, cancelled;

 surface management-notice

Gold, gold lode; closed; surface management-plan

Gold; closed; surface management-plan-WLD REV

Barium, barite; authorized; surface management-notice

Barium, barite; authorized; surface management-plan

Barium, barite; closed, expired; surface management-notice

Barium, barite; closed; surface management-plan

Travertine; closed; surface management-notice

Tungsten, lode and placer; authorized; surface management-plan

Tungsten; closed; surface management-notice

Uranium, uranium and other min., uranium, (U3O8 content);

 closed; surface management-notice

Soil/other, diatomite; authorized; surface management-plan

Other (all locatables, none, to be defined) 

U.S. Forest Service—Management plans

Active

Inactive

Mineral-Resource Potential 101

Figure 28.—Continued
102 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 29. Maps showing mining claims by Public Land Survey System (PLSS) section in the study area for the Southern Idaho and 

Northern Nevada Sagebrush Focal Area, Nevada and Oregon. A, Number of active lode claims and placer claims per section (Dicken 

and San Juan, 2016). B, Thirty-five year averages of the number of active lode claims by section for mining claims located between 1976 

and 2010 (Causey, 2007, 2011).
Twin Falls

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UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

EXPLANATION

Chapter B figure 29a. Number active lode claims per section, closed claims, and active placers.

Number of active lode claims per section

1–8

9–21

22–36

37–51

52–82

Sections with only closed claims (including placer)

Sections with one or more active placer claims outlined in white

A

Mineral-Resource Potential 103

Figure 29.—Continued
104 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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ELMORE

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COUNTY

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COUNTY

TWIN FALLS

COUNTY

ELKO

COUNTY

HUMBOLDT

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 29. Maps showing mining claims by Public Land Survey System (PLSS) section in the study area for the Southern Idaho and 

Northern Nevada Sagebrush Focal Area, Nevada and Oregon. A, Number of active lode claims and placer claims per section (Dicken 

and San Juan, 2016). B, Thirty-five year averages of the number of active lode claims by section for mining claims located between 1976 

and 2010 (Causey, 2007, 2011).
Mineral-Resource Potential 105

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114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

EXPLANATION

Chapter B figure 29b. Lode mining claims 1976-2010.

6.36–39.68

2.61–6.35

0.99–2.60

0.24–0.98

0.01–0.23

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

B

Thirty-five year average of the number of active lode claims by section

Figure 29.—Continued
106 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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COUNTY

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IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 30. Map showing mining districts, mine status, and active exploration areas in or near the study area for the Southern Idaho 

and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (Fernette and others, 2016a,b). USGS, U.S. Geological Survey.
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Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

EXPLANATION

Chapter B figure 31. Mines, Districts, exploration.

Mine status

Active

Inactive

Uncertain

Active exploration areas

Mining districts

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Mineral-Resource Potential 107

Figure 30.—Continued
108 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Mineral Potential of Locatable Minerals

Potential for undiscovered deposits of locatable mineral 

commodities (metallic locatable minerals and nonmetallic 

locatable minerals) within this study area was evaluated for 

locatable commodities gold, silver, uranium, copper, lead, zinc, 

tungsten, diatomite, and barite. These mineral commodities were 

selected for evaluation based on deposits in this study area with 

production and (or) defined resources, prospects, hydrothermal 

alteration, stratigraphy and structure of host rocks, and other 

geological characteristics of deposit types for these commodities 

(Day and others, 2016; appendix 2; table 1). Records of active and 

historic mining claims and surface-management plans provided 

by the BLM and USFS were also used in the assessment process. 

Mineral-resource potential is represented by rated tracts; tracts 

consist of areas favorable for undiscovered deposits of one or 

more commodities that are enclosed by tract boundaries, assigned 

qualitative potential (high, moderate, or low/permissive), and 

assigned a level of potential certainty. Tract boundaries include 

buffers of variable dimensions that reflect spatial uncertainty 

of one or more of the characteristics used to delineate the tract. 

The qualitative mineral potential ratings are derived from a 

classification matrix that merges mineral potential and level of 

certainty (appendix 1). 

Tract delineations and ratings are based entirely on 

publications from libraries and Web sites, and on technical reports, 

documents, and maps from Web sites, downloaded from Web 

sites that are no longer maintained, and provided by companies 

with mineral rights on lands included in the proposed withdrawal 

area. Technical reports, documents, and maps not available on 

Web sites and those provided by companies can be accessed in 

a database that includes mineral deposits with production and 

resources, and mineral exploration sites within the study areas 

(Fernette and others, 2016a). All publications, technical reports, 

documents, and maps used to delineate and rate tracts are cited in 

tract descriptions, in tables of tract characteristics, and in tables of 

deposit production, resources, and mineral exploration sites. We 

did not perform field examinations, mapping, or analyses of the 

tracts, deposits, and resources described in this report section.

Mineral Potential Tracts for Epithermal Gold and 

Silver Deposits

Ten mineral potential tracts for epithermal gold and silver 

deposits were delineated and rated in the study area: tract INEP01, 

Burner; tract INEP02, Cornucopia; tract INEP10, Good Hope; 

tract INEP03, Wood Gulch; tract INEP04, Jarbidge; tract INEP05, 

TJ; tract INEP06, Angel Wing; tract INE07, Oakley; tract INEP08, 

Star Lake; and tract INEP09, Gollaher.

Tract INEP01, Burner—A moderate potential (M), at 

certainty level C, for epithermal gold, silver, and mercury 

deposits is assigned to an area in the Burner Hills, Elko County, 

Nevada (tract INEP01, Burner; fig. 31A; appendix 2). This area 

consists of Paleozoic siliciclastic metasedimentary rocks that are 

unconformably overlain and intruded by Oligocene(?) andesites 

and tuffs, which in turn are overlain by late Miocene to Pliocene 

sedimentary rocks of the Big Island Formation (Coats, 1987; 

Crafford, 2007). Several brecciated quartz veins cut the Paleozoic 

rocks and Oligocene(?) andesites. Mining of these quartz veins, 

mostly in the late 19th century, produced small amounts of silver 

and lead (Emmons, 1910; LaPointe and others, 1991).

The tract was delineated using a 3-km buffer around 

small quartz vein deposits at the Mint and Silver Queen Mines. 

Sinter deposits occur nearby in the Oligocene(?) andesites 

in two places (Rice, 2003). Widespread argillic alteration in 

the Oligocene tuffs and andesites is delineated by interpreted 

ASTER (Advanced Spaceborne Thermal Emission and 

Reflection Radiometer) remote-sensing imagery (Rockwell and 

others, 2015). Fourteen active lode claims in the area, as well 

as closed notices and closed lode claims indicate recent and 

historic exploration activity (tables 16, 17, 18, 19; figs. 28, 29; 

Causey, 2007, 2011).

Tract INEP02, Cornucopia—A moderate potential 

(M), at certainty level C, for epithermal gold and silver, 

and hot spring mercury deposits is assigned to a large area 

encompassing the Cornucopia Mining District and prospects 

to the west in Elko County, Nevada (Tingley, 1992; tract 

INEP02, Cornucopia; fig. 31A; appendix 2). This area 

consists of Eocene sedimentary rocks, Eocene to Oligocene 

andesite lava flows and dikes and rhyolite ash-flow tuffs, 

Miocene rhyolite tuffs and lava flows, and Miocene to 

Pliocene sedimentary rocks (Coats, 1987; Crafford, 2007). In 

the late 19th century, mining of silver-rich quartz veins and 

silicified fault zones in Eocene and Oligocene rocks produced 

an estimated 760,000 oz of silver and 13,000 oz of gold 

(Emmons, 1910; Buchanan, 1981; LaPointe and others, 1991). 

Mine tailings from the Cornucopia district were reprocessed in 

the late 1930s (LaPointe and others, 1991). 

The tract was delineated using a 3-km buffer around 

mines and prospects in the Cornucopia district and includes 

the Wild Horse exploration project, about 6 km to the west 

in the western part of the district (Harrington, 2006). The 

area includes widespread propylitic alteration and local 

silicification, quartz-sericite-pyrite, and argillic alteration 

(Blakestad, 1990; LaPointe and others, 1991). Hot spring 

deposits including sinter are exposed at Wild Horse 

(Harrington, 2006) and are delineated by argillic and advanced 

argillic alteration interpreted from ASTER imagery (Rockwell 

and others, 2015). Composite geochemical anomalies occur in 

the eastern part of the district (Ludington and others, 2006). 

The tract includes active lode claims and active exploration 

areas for gold and silver in the Cornucopia district and at Wild 

Horse (Fernette and others, 2016a; tables 16, 17), and closed 

notices (fig. 28; table 18) and historic lode claims (fig. 29; 

Causey, 2007, 2011).

Tract INEP10, Good Hope—A moderate potential (M), 

at certainty level C, for epithermal gold, silver, and mercury 

deposits is assigned to an area encompassing the Good Hope 

Mining District in Elko County, Nevada (Tingley, 1992; tract 

INEP10, Good Hope; fig. 31A; appendix 2). This area consists 

of small exposures of lower Paleozoic metasedimentary rocks 
Mineral-Resource Potential 109

that are unconformably overlain by Eocene to Oligocene 

andesite lava flows and dikes and rhyolite ash-flow tuffs, 

which are overlain by late Miocene to Pliocene sedimentary 

rocks of the Big Island Formation (Coats, 1987; Crafford, 

2007). Mining in the early 1880s and in 1921 produced about 

91,000 oz silver and minor antimony from quartz veins in 

Eocene or Oligocene tuffs and andesite dikes (Emmons, 1910; 

Lawrence, 1963; Knox, 1970; LaPointe and others, 1991). 

The tract was delineated using a 3-km buffer around 

mines and prospects in the Good Hope district. The tract 

includes several areas of advanced argillic and kaolinitic 

argillic alteration interpreted from ASTER remote-sensing 

data (Rockwell and others, 2015). Composite geochemical 

anomalies occur in the southwest part of the area (Ludington 

and others, 2006). The area has numerous active lode claims 

and active exploration areas for gold and silver (Fernette and 

others, 2016a; tables 16, 17), closed notices, and closed and 

historic lode claims (figs. 28, 29; tables 16, 17; Causey, 2007, 

2011).

Tract INEP03, Wood Gulch—A high potential (H), at 

certainty level D, for epithermal gold and silver deposits is 

assigned to an area encompassing the Wood Gulch Mine and 

the Gravel Creek exploration project, Elko County, Nevada 

(tract INEP03, Wood Gulch; fig. 31A; appendix 2). The 

area consists of upper Paleozoic clastic sedimentary rocks 

unconformably overlain by Eocene volcaniclastic rocks and 

tuffs that are overlain by middle Miocene Jarbidge Rhyolite 

(Coats, 1987; Crafford, 2007; Christensen and others, 2015). 

The Wood Gulch Mine produced moderate amounts of gold 

and silver from narrow quartz veins and silicified zones in 

Paleozoic sedimentary rocks during mining from 1988 to 

1990 (LaPointe and others, 1991; Anderson, 2008). A resource 

of about 93,600 oz of gold has been defined at Wood Gulch 

(table 20). A resource of about 1.36 Moz of gold and about 

20.3 Moz of silver has been defined at Gravel Creek; gold 

and silver occur in quartz veins and hydrothermal breccias in 

Eocene volcaniclastic rocks and tuffs (table 20; Christensen 

and others, 2015; Fernette and others, 2016a).

This tract was delineated using 3-km buffers around the 

Wood Gulch Mine, the Gravel Creek exploration project, 

the Rail Creek target, and hot spring deposits and alteration 

features that are inferred to be surficial expressions of the 

Gravel Creek hydrothermal system (Christensen and others, 

2015). Numerous active lode claims (more than 300) and 

active exploration projects have been located in in this tract 

(Anderson, 2008; Christensen and others, 2015; Fernette and 

others, 2016a; tables 16, 17, 18, 19), and numerous closed and 

historic lode claims are in the tract (figs. 28, 29; tables 16, 17; 

Causey, 2007, 2011).

Tract INEP04, Jarbidge—A high potential (H), at 

certainty level D, for epithermal gold and silver deposits is 

assigned to an area surrounding the Jarbidge Mining District, 

Elko County, Nevada (Tingley, 1992; tract INEP04, Jarbidge; 

fig. 31A; appendix 2). This area mostly consists of lava flows, 

domes, and tuffs of the middle Miocene Jarbidge Rhyolite that 

are overlain by late Miocene sedimentary rocks and tuffs at 

the north end of the tract (Coats, 1987; Crafford, 2007). Lower 

Paleozoic metasedimentary and upper Paleozoic and Triassic 

marine sedimentary rocks are exposed near the south end of 

the tract. In the Jarbidge district, numerous epithermal quartzadularia veins formed along north- to northwest-striking 

normal faults in the Jarbidge Rhyolite during middle Miocene 

hydrothermal activity. Approximately 0.36 Moz of gold and 

1.67 Moz of silver were produced from these veins between 

1910 and 1950 (table 20; Schrader, 1923; LaPointe and others, 

1991). 

This tract was delineated using 3-km buffers around 

mines and prospects in the Jarbidge district. Extensive areas of 

argillic, advanced argillic, and sericitic alteration interpreted 

from ASTER remote-sensing spectra characterize the area 

(Rockwell and others, 2015). Stream-sediment samples have 

anomalous values for gold, arsenic, mercury, and selenium, 

and composite hydrothermal mineralization geochemical 

anomalies both upstream and downstream from the Jarbidge 

district (Ludington and others, 2006). Numerous active lode 

claims have been located in the area (Fernette and others, 

2016a; tables 16, 17); there is active exploration in the area 

and numerous closed and historic lode claims are in the tract 

(figs. 28, 29; tables 16, 17; Causey, 2007, 2011).

Tract INEP05, TJ—A moderate potential (M), at 

certainty level B, for epithermal gold and silver and hot spring 

mercury deposits is assigned to an area near Trout Creek (TJ) 

on the northeast side of Granite Range, Elko County, Nevada 

(tract INEP05, TJ; fig. 31A; appendix 2). This area consists of 

conglomerate, sandstone, siltstone, and volcaniclastic rocks 

of the late Miocene Humboldt Formation that unconformably 

overlie the Late Jurassic Contact pluton (Coats, 1987; 

Limbach, 1991). Late Tertiary ash-flow tuffs, tuffs, and 

tuffaceous sedimentary rocks overlie the Humboldt Formation 

on the east side of the tract. Sedimentary rocks of the 

Humboldt Formation were deposited in north-trending grabens 

that transect the west-elongated Contact pluton. Sinter, 

silicification, advanced argillic, and argillic alteration related 

to a hot spring system are present in Humboldt Formation 

rocks at the TJ (Trout Creek) prospect (Limbach, 1991, 1993). 

The altered rocks locally contain anomalous concentrations 

of gold, silver, mercury, and other elements characteristic of 

epithermal gold and silver deposits.

The tract was delineated using 3-km buffers around 

prospects (Limbach, 1991, 1993) and was expanded to the 

northwest and northeast to encompass adjacent areas of 

advanced argillic and kaolinitic argillic alteration, and hydrous 

silica in Miocene sedimentary rocks interpreted from ASTER 

remote-sensing spectra (Rockwell and others, 2015). Numerous 

active lode claims have been located in the tract, and many 

closed and historic lode claims are in the tract (figs. 28, 29; 

tables 16, 17; Causey, 2007, 2011).

Tract INEP06, Angel Wing—A high potential (H), at 

certainty level C, for epithermal gold and silver deposits is 

assigned to an area along the Nevada-Utah border in northeastern 

Elko County, Nevada, and northwestern Box Elder County, Utah 

(tract INEP06, Angel Wing; fig. 31A; appendix 2). This area 
110 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

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HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Chapter 

INEP01, Burner, M/C

INEP02, Cornucopia, M/C INEP03, Wood Gulch, H/D

INEP04, Jarbidge, H/D

INEP

INEP08, Star Lake, M/B

INEP

INEP10, Good Hope, M/C

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

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COUNTY

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COUNTY

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COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

B gure 31A. Tracts INEP01, INEP02, INEP03, INEP04, INEP05, INEP06, INEP07, INEP08, INEP09, INEP10.

INEP05, TJ, M/B

P06, Angel Wing, H/C

INEP07, Oakley, H/D

09, Gollaher, M/C

High potential, high certainty

EXPLANATION

Assessment tract type—Epithermal gold-silver (mercury)

Moderate potential, moderate certainty

Moderate potential, low certainty

High potential, moderate certainty

A

Mineral-Resource Potential 111

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.
112 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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COUNTY

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HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INHU01, Racetrack, H/D

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

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COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33B. Tract INHU01.

B

High potential, high certainty

EXPLANATION

Assessment tract type—Hydroallogenic volcanic-hosted uranium

Mineral-Resource Potential 113

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
114 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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ELMORE

COUNTY

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COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR02_pmv, Mountain City Polymetallic Vein, H/C

INPR02_pCu, Mountain City Porphyry Copper, M/B

INPR02_pMo, Mountain City Porphyry Molybdenum, M/B

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

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CASSIA

COUNTY

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COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33C. Tracts INPR02.

C

EXPLANATION

High potential, moderate certainty

Assessment tract types—Polymetallic vein, Porphyry copper, Copper 

skarn, and Arc-related porphyry molybdenum (low-fluorine)

Mineral-Resource Potential 115

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
116 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

§ ̈¦84

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£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR03, Cobb Creek, H/D

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33D. Tract INPR03.

D

EXPLANATION

Assessment tract type—Distal disseminated gold-silver

High potential, high certainty

Mineral-Resource Potential 117

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
118 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

§ ̈¦84

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£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR04_pmr, Blue Jacket Polymetallic Replacement, H/D

INPR04_pmv, Blue Jacket Polymetallic Vein, H/C

INPR04_Wv, Blue Jacket Tungsten Vein, M/B

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33E. Tracts INPR04.

E

EXPLANATION

Assessment tract types—Polymetallic replacement, Polymetallic vein, and 

Tungsten vein

High potential, high certainty

Mineral-Resource Potential 119

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
120 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

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£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

COUNTY HUMBOLDT

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR05_WMosk, Alder Tungsten-Molybdenum Skarn, H/D

INPR05_pmv, Alder Polymetallic Vein, M/C

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33F. Tract INPR05.

F

EXPLANATION

Assessment tract types—Tungsten skarn and Polymetallic vein

High potential, high certainty

Mineral-Resource Potential 121

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
122 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

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£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

INPR06_dd, Island Mountain Distal Disseminated Gold-Silver, H/D

INPR06_pmv, Island Mountain Polymetallic Vein and Skarn, H/C

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33G. Tract INPR06.

G

EXPLANATION

Assessment tract types—Distal-disseminated gold-silver, Polymetallic 

vein and skarn

High potential, high certainty

Mineral-Resource Potential 123

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
124 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

COUNTY HUMBOLDT

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR07, Charleston, M/C

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33H. Tract INPR07.

H

EXPLANATION

Assessment tract type—Polymetallic vein

Moderate potential, moderate certainty

Mineral-Resource Potential 125

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
126 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Tw

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR08_pmv, Elk Mountain Polymetallic Vein, M/C

INPR08_WMosk, Elk Mountain Tungsten-Molybdenum Skarn, M/C

INPR08_Cusk, Elk Mountain Copper Skarn, M/C

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
win Falls

£¤93

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33I. Tract INPR08.

I

EXPLANATION

Assessment tract types—Polymetallic vein, Copper skarn, and Tungsten skarn

Moderate potential, moderate certainty

Mineral-Resource Potential 127

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
128 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

§ ̈¦84

£¤26

£¤30

£¤93

£¤9

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR09_pCu, Contact Porphyry Copper, H/D

INPR09_Cusk, Contact Copper Skarn, H/D

INPR09_pmv, Contact Polymetallic Vein, M/C

INPR09_Wsk, Contact_Tungsten Skarn, M/C

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

3

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33J. Tract INPR09.

J

EXPLANATION

Assessment tract types—Porphyry copper, Copper skarn, Polymetallic vein, 

and Tungsten skarn

High potential, high certainty

Mineral-Resource Potential 129

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
130 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

INPR10, Del

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33K. Tract INPR10.

K

EXPLANATION

Assessment tract type—Polymetallic replacement

High potential, high certainty

ano, H/D

Mineral-Resource Potential 131

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
132 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

COUNTY

HUMBOLDT

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR11, Indian 

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33L. Tract INPR11.

n Springs, H/D

L

EXPLANATION

Assessment tract type—Molybdenum-tungsten greisen

High potential, high certainty

Mineral-Resource Potential 133

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
134 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

COUNTY HUMBOLDT

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR12, Gold Basin, M/B

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33M. Tract INPR12.

M

EXPLANATION

Assessment tract type—Polymetallic vein

Moderate potential, low certainty

Mineral-Resource Potential 135

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
136 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Tw

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR13, Texas Canyon, M/C

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
win Falls

£¤93

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33N. Tract INPR13.

N

EXPLANATION

Assessment tract type—Distal disseminated gold-silver and Polymetallic vein

Moderate potential, moderate certainty

Mineral-Resource Potential 137

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
138 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR14, Scraper Springs, M/C

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33O. Tract INPR14.

O

EXPLANATION

Assessment tract type—Climax-type porphyry molybdenum

Moderate potential, moderate certainty

Mineral-Resource Potential 139

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
140 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

§ ̈¦84

£¤26

£¤30

£¤93

£¤

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INPR15_dd, Ashbrook Distal Di

INPR15_pmr, Ashbrook Polyme

INPR15_pmv, Ashbrook Polyme

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤93

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33P. Tract INPR15.

sseminated Silver-Gold, H/D

etallic Replacement, M/C

etallic Vein, M/C

P

EXPLANATION

Assessment tract types—Distal disseminated silver-gold, Polymetallic 

replacement, and Polymetallic vein

High potential, high certainty

Mineral-Resource Potential 141

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
142 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Goose

Lake

£¤95

¬«78

LASSEN

COUNTY

MODOC

COUNTY

ADA

COUNTY

ELMORE

COUNTY 

OWYHEE

COUNTY

HUMBOLDT

COUNTY

WASHOE

COUNTY

HARNEY

COUNTY

LAKE

COUNTY MALHEUR

COUNTY

CALIFORNIA

IDAHO

NEVADA

OREGON

Lakeview

§ ̈¦84

£¤395

£¤395

£¤20

£¤95

120° 118° 116° 

43°

42°

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 118° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

INPR01, Pluton-related Permissiv

Sheldon-Hart Mountain National Wildlife Refuge

Complex Study Area

Southeastern Oregon and North-Central Nevada 

Study Area

Southern 

Norther

Stud

Nevada additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
CASSIA

COUNTY

GOODING

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

TWIN

FALLS

COUNTY

ELKO

COUNTY

BOX ELDER

COUNTY

UTAH

Twin Falls

§ ̈¦80

§ ̈¦84

£¤30

£¤93

£¤30

£¤26

£¤93

114°

Map

area Study areas

IDAHO

MONTANA

OREGON WYOMING

UTAH NEVADA

WASHNGTON

Chapter B gure 33Q. INPR01.

ve, L/B

n Idaho and

rn Nevada 

dy Area

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

EXPLANATION

Assessment tract type—Multiple intrusion-related deposit types

Low potential, low certainty

Q

Mineral-Resource Potential 143

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
144 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

COUNTY HUMBOLDT

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INMS01, VMS Permissive, L/B

INMS03, Rio Tinto 2, H/C

INMS02, Rio Tinto 1, H/D

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33R. INMS01, INMS02.

R

High potential, high certainty

EXPLANATION

High potential, moderate certainty

Assessment tract type—Volcanogenic massive sulfide (Besshi-subtype)

Low potential, low certainty

Mineral-Resource Potential 145

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
146 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INCT02, Willow 1, M/D

INCT01, Carlin Permiss

INCT03, Willow 2, M/

INCT05, Big Springs 2, H/C

INCT04, Big Springs 1, H/D

INCT07, Doby George 2, H/C

INCT08, North Star 1, M/D

INCT06, Doby George 1, H/D

INCT09, North Star 2, M/C

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

sive, L/B

/C

High potential, high certainty

EXPLANATION

High potential, moderate certainty

Assessment tract type—Carlin-type gold (silver, mercury, antimony)

Low potential, low certainty

Moderate potential, high certainty

Moderate potential, moderate certainty

S

Mineral-Resource Potential 147

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
148 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INDT01, Dickshooter, H/D

INDT04, Owyhee-Twin Falls-Cassia Elko, L/B

INDT03, Owyhee-Twin Falls, M/B

INDT02, Dickshooter North, M/C

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B gure 33T. Tracts INDT01, INDT02, INDT03, INDT04.

T

High potential, high certainty

EXPLANATION

Assessment tract type—Lacustrine diatomite

Low potential, low certainty

Moderate potential, moderate certainty

Moderate potential, low certainty

Mineral-Resource Potential 149

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
150 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

T

§ ̈¦84

£¤26

£¤30

£¤93

£¤93

£¤95

ELMORE

COUNTY

GOODING

COUNTY

OWYHEE

COUNTY

TWIN FALLS

COUNTY

ELKO

HUMBOLDT COUNTY

COUNTY

MALHEUR

COUNTY

IDAHO

NEVADA

OREGON

117°00' 116°00' 115°00' 

42°30'

42°00'

41°30'

Base modified from U.S. Geological Survey DEM data, 2016.

Roads and political data copyright © 2014 Esri and its licensors.

Boundary data from San Juan and others (2016).

USA Contiguous Albers Equal Area Conic Projection.

Central meridian, 115° W., latitude of origin, 37.5° N.

North American Datum of 1983.

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

INBB03, Snake Mountains 2, H/C

INBB01, Bedded-barite Permissiv

INBB02, Snake Mountains 1, 

Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 31A–U. Maps showing assessment tracts for metallic locatable minerals and nonmetallic locatable minerals in the study area for the

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (San Juan and others, 2016); USGS, U.S. Geological Survey; 

A, Assessment tracts for epithermal gold-silver (mercury); B, Assessment tract for hydroallogenic volcanic-hosted uranium; C, Assessment tracts for 

polymetallic vein, porphyry copper, copper skarn, and arc-related porphyry molybdenum (low-fluorine); D, Assessment tract for distal disseminated 

gold-silver; E, Assessment tracts for polymetallic replacement, polymetallic vein, and tungsten vein; F, Assessment tracts for tungsten skarn and 

polymetallic vein; G, Assessment tracts for distal disseminated gold-silver, polymetallic vein and skarn; H, Assessment tract for polymetallic vein; 
Twin Falls

£¤93

£¤

£¤30

CASSIA

COUNTY

JEROME

COUNTY

LINCOLN

COUNTY

MINIDOKA

COUNTY

BOX ELDER

COUNTY

UTAH

114°00'

Map

area Study areas

IDAHO

MONTANA

OREGON

WYOMING

NEVADA UTAH

WASHINGTON

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Chapter B figure 33U. Tracts INBB01, INBB02.

ve, L/B

, H/D

U

High potential, high certainty

EXPLANATION

High potential, moderate certainty

Assessment tract type—Bedded barite

Low potential, low certainty

Mineral-Resource Potential 151

I, Assessment tracts for polymetallic vein, copper skarn, and tungsten skarn; J, Assessment tracts for porphyry copper, copper skarn, polymetallic 

vein, and tungsten skarn; K, Assessment tract for polymetallic replacement; L, Assessment tract for molybdenum-tungsten greisen; M, Assessment 

tract for polymetallic vein; N, Assessment tract for distal disseminated gold-silver and polymetallic vein; O, Assessment tract for Climax-type porphyry 

molybdenum; P, Assessment tracts for distal disseminated silver-gold, polymetallic replacement, and polymetallic vein; Q, Assessment tract for 

multiple intrusion-related deposit types; R, Assessment tracts for volcanogenic massive sulfide (Besshi-subtype); S, Assessment tracts for Carlin-type 

gold (silver, mercury, antimony); T, Assessment tracts for lacustrine diatomite; and U, Assessment tracts for bedded barite.—Continued
152 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

consists of upper Paleozoic and Triassic limestone, siltstone, and 

chert overlain by Tertiary conglomerates and Miocene rhyolite 

tuffs. All of these rocks are intruded by Miocene rhyolites and 

dacites (Coats, 1987; Miller and others, 2012). Several types of 

gold and silver deposits occur in the tract, including epithermal 

quartz-carbonate veins that locally crop out in the pre-Tertiary 

limestones, disseminated deposits in Tertiary conglomerates and 

underlying calcareous sandstone and limestone, and brecciahosted deposits along the margins of a Miocene rhyolite intrusion 

(Goodall, 2003; Kehmeier, 2009; Pilot Gold, 2011; Ramelius 

Resources Limited, 2012). 

The tract was delineated using a 3-km buffer around 

the Angel Wing, Viper, and White Rock exploration projects 

(Fernette and others, 2016a). Surface samples and significant 

intervals in drill holes at the Viper and Angel Wing exploration 

projects locally contain highly anomalous concentrations of 

gold (more than 1 part per million [ppm]) and silver (more 

than 20 ppm) (Pilot Gold, 2011; Ramelius Resources Limited, 

2012). The White Rock project has a resource (non-NI 43-101 

compliant) of approximately 150,000 oz gold (Goodall, 2003; 

Kehmeier, 2009). Stream-sediment samples from the area 

have anomalous concentrations of mercury and selenium. 

Numerous active lode claims have been located and three 

active exploration areas are in the tract (Fernette and others, 

2016a; tables 16, 17, 18, 19). Active notices, closed plans of 

operations, and numerous closed and historic lode claims are 

in the tract (figs. 28, 29; tables 16, 17; Causey, 2007, 2011).

Tract INEP07, Oakley—A high potential (H), at certainty 

level D, for epithermal gold and silver deposits is assigned 

to an area in the Goose Creek Basin on the west side of the 

Middle Mountain in southwestern Idaho just north of the Utah 

border (tract INEP07, Oakley; fig. 31A; appendix 2). The 

area consists of the late Miocene Salt Lake Formation that 

was deposited in Goose Creek Basin, a north-trending graben 

on the west side of Middle Mountain (Sturm, 2013). Middle 

Mountain is along the western edge of the Albion-Raft RiverGrouse Creek metamorphic core complex, which is composed 

of ductilely deformed Precambrian through Mesozoic intrusive 

and metamorphic rocks that are structurally overlain by a 

series of brittle Paleozoic rocks, including quartzite, limestone, 

and minor phyllite (Sturm, 2013). The Goose Creek Basin is 

filled by the late Miocene Salt Lake Formation, which consists 

of tuffaceous siltstone, sandstone, conglomerate, and tuffs, 

and locally contains hot spring deposits. The Blue Hill Creek 

exploration project has a resource (NI 43-101 compliant) of 

approximately 230,400 oz of gold (appendix 2; Sturm, 2013).

The tract was delineated using a 3-km buffer around 

epithermal prospects in the late Miocene sedimentary rocks, 

including the drilled gold resource at Blue Hill Creek exploration 

project, prospects at Cold Creek with strongly anomalous gold 

values in drill holes, and active exploration areas (Sturm, 2013). 

Hot spring deposits, including sinter and silicified hydrothermal 

vent breccia, are preserved at the Blue Hill Creek exploration 

project in the Miocene sedimentary rocks (Sturm, 2013). A 

pronounced radiometric thorium/potassium (Th/K) low over 

the Miocene sedimentary rocks (Day and others, 2016) is 

suggestive of potassic alteration (see, for example, Morrell and 

others, 2011). The tract includes four active exploration projects, 

numerous active lode claims (tables 16, 17), and numerous 

closed and historic lode claims (figs. 28, 29; tables 16, 17; 

Causey, 2007, 2011).

Tract INEP08, Star Lake—A moderate (M) potential, with 

certainty B, for epithermal gold and silver deposits is assigned 

to an area of the Owyhee Plateau along the Humboldt-Elko 

County line, about 55 km northeast of the town of Paradise 

Valley (tract INEP08, Star Lake; fig. 31A; appendix 2). This 

area is characterized by subhorizontal Miocene ash-flow tuffs, 

overlain by slightly younger basalts and continental sediments. 

No mineral exploration activity was recorded prior to 2006 

when a project was established to explore stream-sediment 

geochemical anomalies reported by the USGS (Coombs and 

others, 2002; Ludington and others, 2006). 

The tract was delineated using a 3-km buffer around the 

project boundaries (Fernette and others, 2016a). The streamsediment geochemical anomalies that led to discovery of the 

prospect are characterized by antimony values as high as 

550ppm, 5–7 ppm arsenic, and 50–75 ppm zinc. Detailed ground

geochemical surveys have delineated arsenic anomalies of 100 to 

600 ppm (Altan Nevada Minerals Ltd., 2016). A small positive 

residual Bouguer gravity anomaly that coincides with the central 

part of the project area has been interpreted to be similar to the 

signature of the northern part of the Carlin Trend (Altan Nevada 

Minerals Ltd., 2016). ASTER satellite imagery shows scattered 

pixels indicative of sericite (Rockwell and others, 2015). Modeling 

of the gravity data suggests that the Paleozoic basement is less 

than 1 km beneath the surface (Ponce, 2004); the original target 

was Carlin-type gold mineralization along the extension of the 

Carlin Trend. However, four widely spaced core holes (340–770m

in depth) in 2009 revealed a hydrothermal system in Miocene 

rhyolite at depths below 450 m that is characterized by quartz 

veining, argillization, and brecciation, with anomalous gold values 

of as much as 0.101 g/t (gram per metric ton; approximately equal 

to part per million; Altan Nevada Minerals Ltd., 2016). The tract 

includes closed and historic lode claims and an active exploration 

area (figs. 28, 29, 30; tables 16, 17; Causey, 2007, 2011)

Tract INEP09, Gollaher—A moderate potential (M), 

with certainty level C, for epithermal gold and silver deposits is 

assigned to an area centered on the Gollaher exploration project 

(Fernette and others, 2016a), which extends into the proposed 

withdrawal area (tract INEP09, Gollaher; fig.31A; appendix 

2). This tract is based on several prospects in Mississippian to 

Permian siliciclastic and carbonate rocks and Miocene tuffaceous 

volcanic and sedimentary rocks that locally are overlain by 

Miocene Jarbidge Rhyolite or Quaternary alluvium (Crafford, 

2007). The tract includes these Paleozoic, Miocene, and 

Quaternary units and a 1-km buffer to account for volcanic rock 

and alluvial cover and uncertainty of mapped contacts. Although 

this active exploration area has potential for Carlin-type gold 

deposits and epithermal gold and silver deposits, according to 

company reports (West Kirkland Mining Inc., 2010, 2012), the 

area more closely resembles nearby epithermal tracts (for example, 

tract INEP06, Angel Wing) that include gold and silver vein 
Mineral-Resource Potential 153

mineralization in volcanic rocks, and disseminated gold and silver 

mineralization in underlying sedimentary rocks. The exploration 

projects derive from rock and soil geochemical surveys and 

drilling in the 1980s (West Kirkland Mining Inc., 2010, 2012). 

The tract encloses an active exploration area (Fernette and others, 

2016a) with one drill intercept that contains 18.9 ppm gold over 

60 cm (West Kirkland Mining Inc., 2010, 2012). Although little or 

no argillic or sericitic alteration is evident on interpreted ASTER 

imagery (Rockwell and others, 2016), quartz was mapped from 

interpretation of ASTER thermal emission data (Rockwell and 

Hofstra, 2008). There is one closed notice for gold on the east 

side of the tract (figs. 28, 29; tables 18, 19). The tract is largely 

on private land, which accounts for the paucity of published 

information on exploration activity.

Buffering Epithermal Gold and Silver Tracts

The epithermal gold and silver tracts described previously 

were delineated from characteristics of epithermal gold, silver, 

and mercury deposits on the basis of the deposit model, which 

was assembled from characteristics of well-documented 

epithermal gold, silver, and mercury deposits and the magmatichydrothermal systems that formed the deposits (Day and others, 

2016; appendix2). Some of these characteristics may be concealed

(for example, altered rocks covered by younger rocks; drilldefined gold and silver resources; deposits identified by drillhole intercepts with elevated gold and silver values) and do not 

appear on published maps (geologic; topographic) or in other 

publications. Gold and silver occurrences on published maps 

and in other publications were the first criterion used to delineate 

possible concealed and unmapped epithermal gold and silver 

deposits. Other criteria used include the alteration and geochemical 

signatures of the magmatic-hydrothermal systems that form 

epithermal gold and silver deposits. The approximate diameters 

of footprints (surface exposures) of well-exposed epithermal 

gold and silver systems, based largely on mapped gold and silver 

occurrences, alteration, and geochemistry, range from several 

hundred meters to about 10 km, and are mostly 10–20 km2 in the 

study areas (appendix 5). If the areas of well-exposed systems 

are geometrically represented by circles concentric to mapped 

or published gold and silver occurrences, then circles enclosing 

systems that formed epithermal gold and silver deposits in the 

study areas have radii of 1.8–2.6 km. Based on the distribution 

and spatial density of gold and silver occurrences in the study 

areas, a circle with a radius of 3 km centered on occurrences 

was used to delineate tracts. Tract boundaries represent the 

merged circumferences of circles concentric to all gold and silver 

occurrences within the tract.

Mineral Potential Tract for Hydroallogenic 

Uranium Deposits

One mineral potential tract for hydroallogenic uranium 

deposits was delineated and rated in this study area: tract 

INHU01, Racetrack. 

Tract INHU01, Racetrack—Nineteen uranium 

occurrences near Mountain City, Nevada, support delineation 

of the Racetrack permissive tract that has high potential (H) 

for uranium deposits, with certainty level D (tract INHU01, 

Racetrack; fig. 31B; appendix 2). The uranium occurrences, 

which fit the hydroallogenic uranium deposit type (Day and 

others, 2016), are near a Tertiary erosional surface represented 

by the contact between Cretaceous quartz monzonite and 

overlying Miocene volcanic rocks (Garside, 1973; Proffitt and 

others, 1982). The tract boundary is based on the distribution 

of the uranium occurrences, the presence of favorable host 

rocks, and anomalous uranium values (as much as 479 ppm 

uranium) in soil, rock, and talus samples (Proffitt and others, 

1982; U.S. Geological Survey, 2005; Fernette and others, 

2016a; Smith, 1997; Smith and others, 2016).

Cumulative production of 20,876 lbs U3

O8 in the 1950s 

and 1960s is reported from three mines and claim groups in 

this tract; the Rim Rock Mine (4,240 lbs of U3

O8), Race Track 

Mine (9,866 lbs of U3O8), Happy Joe Mine (2,259 lbs of U3O8), 

and the South Fork and Pixley Claims (4,511 lbs of U3O8; table 

20; Garside, 1973; Proffitt and others, 1982). Rock samples 

collected near the uranium occurrences contain 6–3,745 ppm 

U3O8, and the average grade of ore ranged from 0.12 percent to 

0.5 percent U3O8 (Garside, 1973; Proffitt and others, 1982). 

The Race Track Mine and Autunite prospect were explored 

by Samba Gold (Samba Gold Inc., 2007a,b). Bayswater Uranium 

Corporation established a land position in the area and acquired 

a resource from Pathfinder Mines Corporation of 1.1 Mlbs of 

U3O8 defined by 359 holes drilled from 1967 to 1983 (Bayswater 

Uranium Corporation, 2007). The tract boundary was modified 

from Proffitt and others (1982) by adding a 2-km buffer to correct 

for an error in georeferencing the original NURE (National 

Uranium Resource Evaluation) tract. Uranium occurrences and 

geochemical anomalies are located in the southwestern part of 

the tract. The rest of the tract is delineated by the occurrence of 

permissive Tertiary sedimentary and volcanoclastic source and 

host rocks that were deposited on a Tertiary erosional surface.

Hydroallogenic deposits form when uranium-enriched 

fluids are released from volcanic source rocks, transported by 

aqueous solutions, and concentrated in the same or nearby rocks 

(Mickle and Mathews, 1978). Three types of hydroallogenic 

deposits are identified in the Racetrack tract: (1) secondary 

uranium minerals in paleochannels or lows that are filled 

with Tertiary conglomerate, sandstone, and volcanic ashflow tuffs; (2) uranium concentrated in shear zones and joints 

within volcanic rocks; and (3) uranium in Cretaceous granite 

shear zones and grus that were originally overlain by Tertiary 

sedimentary and volcanic ash-flow tuffs (Proffitt and others, 

1982). In this tract, the sources of uranium are likely weathered 

Eocene volcanic rocks with some contribution from weathered 

Cretaceous granites. The deposits formed between 40 and 20 

million years ago where groundwater leached uranium from 

local ash-flow tuffs or granites and redeposited this uranium 

in zones of high porosity and permeability (faults or poorly 

consolidated sediments below ash-fall tuffs) (Proffitt and 

others, 1982). Uranium was chemically trapped and removed 
154 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

from groundwater by montmorillonite clay that is derived 

from alteration of volcanic rocks and by carbonaceous debris 

incorporated into the volcanic and sedimentary host rocks. 

Potential for significant uranium deposits may be limited by the 

disparate nature of these chemical traps within host sediments.

Stratigraphy Favorable for Uranium Deposits

In the easternmost portion of the study area, uranium-rich 

lignite and carbonaceous shale have been identified in the Goose 

Creek Basin (U.S. Department of Energy, 1980; Gallant, 1982; 

also see report section “Leasable Minerals; Coal”). Uranium 

produced in this area would likely be a byproduct of lignite 

mining, which is unlikely to occur based on the low quality of 

lignite as a solid fuel.

A number of uranium occurrences are described near 

Contact, Elko County, Nevada, including the Pink Horse, 

Contact occurrences, Texas Canyon project, and Podner 

and Prince Claims (U.S. Geological Survey, 2005; Fernette 

and others, 2016a). These occurrences may represent the 

hydroallogenic uranium deposit type similar to those in the 

Racetrack tract. In 2007, Gold Reef International evaluated 

a 0.50-square-mile (mi2) area around the Prince Claim and 

reported anomalous radioactivity and rock samples that 

contained as much as 1 percent U3O8 within a mineralized 

fault breccia (Gold Reef International, 2007). However, no 

resources or production are reported for occurrences in this area; 

therefore, a uranium tract was not delineated. 

Scattered uranium occurrences associated with 

polymetallic deposits and with volcanic domes, intrusions, and 

volcanoclastic sediments are reflected mainly by geochemical 

and geophysical anomalies, trenches, and prospect pits (Berry 

and others, 1982; Castor and others, 1982a,b; Gallant, 1982; 

Garside, 1982; Proffitt and others, 1982; Dayvault, 1983; U.S. 

Geological Survey, 2005; Fernette and others, 2016a). Castor 

and others (1982a,b) also note that Basin and Range faulting 

throughout the region has created basins that, coupled with 

abundant uranium-rich felsic volcanic and granitic source rocks, 

hold potential for hosting uranium deposits that has not been 

evaluated. However, no clear clustering of these anomalies 

occurs in the study area, nor is there reported production or 

reserves that would support delineation of higher potential 

tracts.

Mineral Potential Tracts for Intrusion-Related 

Deposits, Including Porphyry Copper, Porphyry 

Molybdenum, Polymetallic Skarn, Replacement, 

and Vein, Tungsten Greisen Deposits, and Distal 

Disseminated Silver-Gold Deposits

Fifteen tracts and tract groups were delineated and 

rated for various intrusion-related deposits, including 

porphyry copper and molybdenum deposits; polymetallic 

(copper-lead-zinc-tungsten-silver-gold) skarn, replacement, 

and vein deposits; and distal disseminated silver-gold deposits: 

tract INPR02, Pluton-related Permissive; tract INPR02_pCu, 

Mountain City Porphyry Copper, tract INPR02_pMo, 

Mountain City Porphyry Molybdenum, and tract INPR02_pmv, 

Mountain City Polymetallic Vein; tract INPR03, Cobb Creek; 

tract INPR04_pmr, Blue Jacket Polymetallic Replacement, 

tract INPR04_pmv, Blue Jacket Polymetallic Vein, and tract 

INPR04_Wv, Blue Jacket Tungsten Vein; tract INPR05_

pmv, Alder Polymetallic Vein and tract INPR05_WMosk, 

Alder Tungsten-Molybdenum Skarn; tract INPR06_dd, 

Island Mountain Distal Disseminated Gold-Silver and tract 

INPR06_pmv, Island Mountain Polymetallic Vein and Skarn; 

tract INPR07, Charleston; tract INPR08_Cusk, Elk Mountain 

Copper Skarn, tract INPR08_WMosk, Elk Mountain TungstenMolybdenum Skarn, and tract INPR08_pmv, Elk Mountain 

Polymetallic Vein; tract INPR09_pCu, Contact Porphyry 

Copper, tract INPR09_Cusk, Contact Copper Skarn, tract 

INPR09_Wsk, Contact Tungsten Skarn, and tract INPR09_pmv, 

Contact Polymetallic Vein; tract INPR10, Delano; tract INPR11, 

Indian Springs; tract INPR12, Gold Basin; tract INPR13, Texas 

Canyon; tract INPR14, Scraper Springs; tract INPR15_pmr, 

Ashbrook Polymetallic Replacement, tract INPR15_dd, 

Ashbrook Distal Disseminated Silver-Gold, and tract INPR15_

pmv, Ashbrook Polymetallic Vein (San Juan and others, 2016).

Tract INPR02_pCu, Mountain City Porphyry Copper—

There is moderate (M) potential, with certainty level B, for 

porphyry copper deposits in the Mountain City and Hicks 

Mining Districts near Mountain City, Elko County, Nevada 

(LaPointe and others, 1991; fig. 31C; appendix 2). The 

geology of the area is characterized by Paleozoic sedimentary 

and metavolcanic formations that are intruded by the Late 

Cretaceous Mountain City, Enright Hill, McDonald Creek, and 

Summit Creek plutons (Coats and McKee, 1972; Crafford, 

2007; du Bray and Crafford, 2007). Eocene volcanic and 

volcaniclastic rocks rest unconformably on Mesozoic and 

older strata. Miocene volcanic and volcaniclastic rocks cover 

older strata and are most widespread to the north and east of 

the Mountain City district. Paleozoic formations are tilted 

moderately to steeply northward and are cut by reverse faults. 

Younger, steep normal faults cut the quartz monzonite and 

older rocks. Miocene and older rocks are in turn cut by younger 

north- and east-trending normal faults (Coats, 1987; LaPointe 

and others, 1991).

In the Mountain City district, silver-gold lode and 

associated placer deposits were discovered in 1869 causing 

a rush that led to the founding of the town of Mountain City. 

Mining from polymetallic veins in the district continued into 

the early 1900s. After a period of low activity, mining in the 

district resumed in 1931 with the discovery of the Rio Tinto 

volcanogenic massive sulfide and the redevelopment of Van 

Duzer placer deposits (Coats and Stephens, 1968; Smith, 

1976; LaPointe and others, 1991). Mining activity in the Hicks 

district, 15 km east of Mountain City, started around 1880; 

however, no production was recorded during this period. 
Mineral-Resource Potential 155

Polymetallic veins around the Enright Hill pluton produced 

small quantities of lead-zinc-silver ore with minor gold and 

copper as byproducts from 1950 to 1952. The Enright Hill 

area was explored in the 1970s and 1980s for precious metals 

(Smith, 1976; LaPointe and others, 1991).

The tract was delineated by aggregating 3-km buffers 

around the Mountain City and Summit Creek plutons, and 

mines around the Enright Hill pluton in the Hicks district 

(Crawford, 2007; Fernette and others, 2016a). In the Mountain 

City district, soil and stream-sediment geochemistry is 

characterized by moderately high to high concentrations 

(8 to 15 times background) of arsenic and moderately high 

concentrations (4 to 7 times background) of silver and 

molybdenum. In the Hicks district, soil and stream-sediment 

geochemistry is characterized by moderately high to high 

concentrations (8 to 15 times background) of cadmium and 

moderately high concentrations (4 to 7 times background) 

of silver, beryllium, molybdenum, and tin (U.S. Geological 

Survey, 2016b).

The Mountain City district is located over a magnetic high 

that images the Mountain City pluton. Mines and prospects 

in the district are also cospatial with elevated uranium 

concentrations reflected by radiometric measurements. The 

uranium/thorium (U/Th) map around these mines is high. 

In contrast, the Hicks district occurs over a magnetic low 

that is cospatial with elevated northeast-trending uranium 

concentrations best reflected by the uranium/thorium (U/Th) 

map (Day and others, 2016).

Alteration is weakly-developed over the Golden Ensign, 

Nelson, and New Yorkey’s Claim based on interpretation of 

ASTER satellite imagery of (Rockwell and others, 2015). 

In contrast, a northeast trend of advanced argillic alteration 

minerals and ferric iron occurs along the Bieroth, Enright Hill, 

and Never Sweat Mines in the Hicks district. Advanced argillic 

alteration minerals and ferric iron are relatively well-developed 

on the McDonald Creek stock to the north, where the Copper 

Mountain copper occurrence is located.

Previous assessments estimate that all or parts of this 

tract are permissive for distal disseminated, polymetallic 

replacement, skarn, and porphyry copper deposits (U.S. 

Geological Survey, 2001; Wallace and others, 2004; Parks and 

others, 2016). There are 92 active lode claims in the tract area 

(Dicken and San Juan, 2016).

One porphyry-related occurrence is known in the 

Hicks district. About 1.5 km east of the Enright Hill dioritegranodiorite pluton, the Never Sweat Ag-(Au-Cu-Pb-Zn) quartz 

vein is associated with an altered porphyry dike emplaced in 

metamorphosed siltstone and shale units. The Never Sweat 

Mine is controlled by a 300-m-long northeast structure on 

which the Bieroth Au-Ag-(Pb-Zn), Enright Hill Au veins 

are also located (Smith, 1976; LaPointe and others, 1991). 

From 1950 to 1952, mines on Enright Hill produced a small 

quantity of lead-zinc-silver ore with minor gold and copper as 

byproducts. The area was explored throughout the 1970s and 

1980s for porphyry and precious metals deposits, and a drilling 

project in 1989 delineated a small gold resource at the Enright 

Hill Mine. Another copper occurrence is found at the Copper 

Mountain site to the north in the McDonald Creek pluton (U.S. 

Geological Survey, 2016a).

No porphyry copper deposits are known in the Mountain 

City district. However, along the southern contact between the 

Mountain City intrusion and Paleozoic rocks, mineralized rock 

exhibits characteristics that contrast with those of the more typical 

precious and base metal veins in the district. The Golden Ensign 

Ag-Au-W-(Cu-Mo-Pb-Zn) and Nelson Ag-(Au-Cu-Zn-Pb-As) 

skarns formed at the contact of a quartz monzonite intrusion with 

limestone. Mineralization is associated with dikes and irregular 

masses of altered aplite (Emmons, 1910). Sulfides include pyrite, 

chalcopyrite, galena, sphalerite, chalcocite, silver sulfosalts, and 

arsenopyrite. Scheelite and molybdenite are also present, but there 

is no recorded production of these metals. At the New Yorkey’s 

Claim, copper and gold occurs in sheeted veins that contain pyrite, 

copper minerals, and iron oxides (Smith, 1976; LaPointe and 

others, 1991). The Golden Ensign (Silver Banner) and Nelson 

Mines were among the largest producers in the district. They were 

active in the 1870s, in the early 1900s, and in the 1920s.

Tract INPR02_pMo, Mountain City Porphyry 

Molybdenum—There is moderate (M) potential, with certainty 

level B, for intrusion-related low-fluorine porphyry molybdenum 

deposits in the Mountain City district near Mountain City, Elko 

County, Nevada (LaPointe and others, 1991; fig. 31C; appendix2).

The geology, regional geochemical, geophysical, and remotesensing data that characterize the tract are described in report 

section “Tract INPR02_pCu, Mountain City Porphyry Copper.” 

Low-fluorine porphyry molybdenum is represented by the 

Huber Hill (Granite Ridge) prospect located in the Mountain 

City pluton 3 km east-southeast of Mountain City (Smith, 1976; 

LaPointe and others, 1991; Sherlock and others, 1996). In the 

Mountain City district, however, molybdenite also occurs at 

the Golden Ensign Ag-Au-W-(Cu-Mo Pb-Zn) skarn deposit. 

Molybdenum mineralization at Huber Hill consists of quartzpyrite-molybdenite veins in quartz monzonite near the contact 

with a granite porphyry. Molybdenite also occurs disseminated 

and in veins throughout the larger Granite Ridge area around 

Huber Hill (Smith, 1976; LaPointe and others, 1991). 

Molybdenum at Huber Hill was first identified in 1969. 

The prospect was drilled in the 1970s and early 1980s, but 

results did not indicate sufficient tonnage and grade to support 

an economically viable operation (LaPointe and others, 1991). 

Processed ASTER satellite imagery shows a well-developed 

1,000- by 300-m northeast-trending zone of advanced argillic 

alteration minerals and lesser sericite in this area.

Tract INPR02_pmv, Mountain City Polymetallic Vein—

There is high (H) potential, with certainty level C, for intrusionrelated silver-gold-(copper-lead-zinc) polymetallic vein deposits 

in the Mountain City and Hicks districts, Elko County, Nevada 

(LaPointe and others, 1991; fig. 31C; appendix 2). The geology, 

regional geochemical, geophysical, and remote-sensing data 

that characterize the tract are described in report section “Tract 

INPR02_pCu, Mountain City Porphyry Copper.”
156 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Polymetallic veins in the Mountain City district with 

reported production include the Independent, Mariposa, 

Mountain City, Protection, and Resurrection Mines. These 

mines produced precious metals and small quantities of 

copper, lead, and zinc from veins that occur mainly in the 

Late Cretaceous Mountain City quartz monzonite. Near the 

southern margin of the pluton, veins also cut Paleozoic rocks. 

The veins commonly occupy northwest-trending faults. Ore 

minerals in the quartz-pyrite-arsenopyrite veins consist of 

chalcopyrite, galena, sphalerite, tetrahedrite, argentite, and 

free gold (Coats and Stephens, 1968; Smith, 1976; LaPointe 

and others, 1991).

The Protection Au-Ag-(Cu-Pb-Zn), Resurrection 

Ag-(Cu-Pb), and Mountain City Ag-(Au-Cu-Pb) polymetallic 

veins were the district’s major producers into the early 20th 

century, but small and sporadic production continued until the 

early 1980s. In the early 1980s, a silver leach plant operated 

at the old Protection Mine (Smith, 1976; LaPointe and 

others, 1991). In the mid to late 1980s, exploration activity 

for precious metals increased. One exploration project (the 

Mountain City property) is active in the district (Fernette and 

others, 2016a). On the Mountain City property, sampling by 

First American Siver Corp. obtained silver values of as much 

as 84.9 opt, and gold values of as much as 0.218 opt from 

quartz veins (First American Silver Corp., 2011).

Tract INPR03, Cobb Creek—There is high (H) 

potential, with certainty level D, for intrusion-related, distal 

disseminated gold-silver deposits in the Mountain City and 

Aura districts near Mountain City, Elko County, Nevada 

(LaPointe and others, 1991; fig. 31D; appendix 2). The 

geology of the area is characterized by Paleozoic sedimentary 

and metavolcanic formations that are intruded by Late 

Cretaceous continental margin arc intrusions. Eocene volcanic 

and volcaniclastic rocks rest unconformably on Mesozoic 

plutons and older strata. Miocene volcanic and volcaniclastic 

rocks occur mostly outside the district to the northwest and 

southeast (Coats, 1987; Crafford, 2007). 

The Cobb Creek-McCall deposit was discovered in 

1983, and geophysical and geochemical surveys and drilling 

identified the Beaver Creek oxide gold target in the early 

1990s. Active exploration has continued to the present. In 

2004, the Cobb Creek-McCall near-surface oxide gold inferred 

mineral resource was estimated at 1.36 million short tons at 

0.040 opt gold, and the sulfide gold inferred mineral resource 

was estimated at 2.38 million short tons at 0.050 opt gold 

(Pawlowski, 2006).

The tract was delineated by aggregating 3-km buffers 

around the Cobb Creek, McCall, and Beaver Creek active 

exploration projects, and the antimony-precious metal vein 

at the Blue Ribbon-Boyce Mine (LaPointe and others, 1991; 

Fernette and others, 2016a). Regional stream-sediment 

geochemical samples do not cover the tract area. Surrounding 

the tract, stream-sediment data show the area to be characterized 

by high concentrations (more than 16 times background) of 

antimony, moderately high to high concentrations (8 to 15 times 

background) of silver, arsenic, cadmium, and molybdenum, 

and moderately high concentrations (4 to 7 times background) 

of copper (U.S. Geological Survey, 2016b). The tract is 

located at the northern margin of a broad gravity anomaly. 

A magnetic high to the north dips into the tract area imaging 

the continuation of a probable intrusion at depth. Uranium/

thorium (U/Th) is also moderately high in the area of the Cobb 

Creek resource, as reflected by radiometric measurements (Day 

and others, 2016). Interpretation of ASTER satellite imagery 

shows minor ferric iron zones over the Cobb Creek-McCall and 

Beaver Creek areas, and small carbonate-propylitic and ferric 

iron zones over the Silver Creek intrusion west, and 2 km north 

of the Blue Ribbon-Boyce Mine (Rockwell and others, 2015).

Previous assessments estimate that all or parts of this 

tract are permissive for distal disseminated, polymetallic 

replacement, skarn, and porphyry copper deposits (U.S. 

Geological Survey, 2001; Wallace and others, 2004; Parks and 

others, 2016). There are 42 active lode claims and 1 placer 

claim in the tract (Dicken and San Juan, 2016).

The gold-silver mineralization at the Cobb Creek 

project is considered similar to Carlin-type gold deposits by 

the deposit owners. However, proximity to intrusions and 

association of base metal-silver vein and skarn deposits with 

those intrusions suggests that the gold-silver deposit type is 

distal disseminated (Cox and Singer, 1990). The intrusionrelated Mountain Laurel Ag-(Au-Cu-Pb) and the Silver King 

Ag-Pb-(Au-Cu-Zn) mines are located in the vicinity of the 

Cobb Creek project. In the early 1980s, a small silver mining 

operation was still active at the Silver King Mine (LaPointe 

and others, 1991).

Antimony-bearing gold-silver distal disseminated 

deposits are surrounded by the Late Cretaceous Silver Creek 

and Winter Creek granitic intrusions to the south and west, 

and by the Mountain City granitic pluton to the north (U.S. 

Geological Survey, 2016a). The 100 Ma age of mineralization 

obtained from fuchsite at Cobb Creek is consistent with ages 

obtained from these nearby intrusions (Pawlowski, 2006). 

Three periods of structural deformation have been identified 

in the area. Late Paleozoic deformation produced N. 40°–70°

E. asymmetrical folds with steep dips to the northwest, and 

low-angle N.70°E.-striking shear zones. This event was 

followed by pre-Late Cretaceous N. 60°–70° W. and Late 

Cretaceous high-angle N. 30° E.- and N. 30° W.-trending 

faults. The ore zone at the Cobb Creek project is imaged by 

distinctive resistivity highs with no associated aeromagnetic 

response. Geochemical surveys show anomalous gold, silver, 

arsenic, antimony, copper, and molybdenum, with a strong 

correlation between gold and arsenic. Most of the Cobb 

Creek area is covered by alluvium. However, drilling has 

shown that deposits consist of bull quartz-calcite-pyritearsenopyrite stockworks, veins, and breccias that are hosted 

by argillized, potassium-metasomatized, and weakly silicified 

greenstone and argillite units of the Ordovician Valmy 

Formation. Probable similar antimony-gold deposits also 

occur at the historic Blue Ribbon-Boyce Mine, which has 

produced antimony from stibnite-bearing quartz stringers and 

disseminations. The Blue Ribbon-Boyce Mine is located at the 
Mineral-Resource Potential 157

margin of the Silver Creek biotite granite stock, about 4 km 

southwest of the Cobb Creek deposit (LaPointe and others, 

1991).

Tract INPR04_pmr, Blue Jacket Polymetallic 

Replacement—There is high (H) potential, with certainty level 

D, for intrusion-related silver-lead-(gold-copper-antimony-zinc) 

polymetallic replacement deposits in the Aura, Centennial, and 

Edgemont districts 20 km southwest of Mountain City, Elko 

County, Nevada (LaPointe and others, 1991; fig. 31E; appendix 

2). The geology of the area is characterized by deformed lower 

Paleozoic sedimentary rocks. These rocks are intruded by the 

Late Jurassic Columbia, Trail Creek, and White Rock dioritic 

to granodioritic stocks, dikes, and sills (LaPointe and others, 

1991; du Bray and Crafford, 2007). Intrusive and sedimentary 

rocks are displaced as much as 600 m by north- to northeasttrending normal faults. Eocene volcanic and volcaniclastic rocks 

rest unconformably on older strata. These rocks are covered 

by Miocene volcanic and volcaniclastic rocks and Quaternary 

alluvial deposits (Coats, 1987; LaPointe and others, 1991; 

Crafford, 2007).

The Aura district was organized in 1869, and ten lode 

mines and several placer claims were active in the 1870s. Placer 

mining declined between the 1880s and early part of the 20th 

century, but silver-rich ores in lode deposits were produced until 

the late 1940s. Production continued intermittently from a few 

mines into the 1980s (Smith, 1976; LaPointe and others, 1991). 

Significant production was derived from the Blue Jacket Mine, 

which in 1989 contained an estimated resource of 2 million 

short tons at 0.01 opt gold, 2.2 opt silver, 0.25 percent copper, 2 

percent lead, and 1.8 percent zinc (Long and others, 1998). Blue 

Jacket is an exploration project that is currently active (Fernette 

and others, 2016a). In contrast to the Aura district, lode deposits 

in the Edgemont district to the west were not discovered until the 

1890s. Most gold and silver production occurred between 1900 

and 1909. Mining revived in the 1930s through the early 1970s. 

During this period, lead was the major commodity produced, 

with lesser gold and silver, and minor copper, zinc, and tungsten. 

Exploration in the 1980s focused on Carlin-type gold deposits in 

the area (Smith, 1976; LaPointe and others, 1991). 

The tract was delineated by aggregating 3-km buffers 

around the mines and prospects (Fernette and others, 2016a; 

U.S. Geological Survey, 2016a). It encompasses the Mesozoic 

intrusions. Soil and stream-sediment geochemistry in the 

tract is characterized by high concentrations (more than 16 

times background) of antimony; moderately high to high 

concentrations (8 to 15 times background) of arsenic, cadmium, 

and magnesium; and moderately high concentrations (4 to 7 

times background) of silver, copper, molybdenum, lead, and 

silver (U.S. Geological Survey, 2016b). The tract occurs over 

a local low-intensity magnetic high and at the northern margin 

of a broad gravity low. The tract area is located at the margin of 

a local thorium high as reflected by radiometric measurements 

(Day and others, 2016). Prominent argillic alteration and ferric 

iron zones occur in quartzite along the 6-km east-northeasttrending range where the Bull Run Mine is located, and along 

the range where the Lucky Girl Mine is situated, based on 

interpretation of ASTER satellite imagery (Rockwell and 

others, 2015). Previous assessments estimate that the tract 

area is favorable and prospective for intrusion-related deposits 

(Wallace and others, 2004; Parks and others, 2016). There are 

169 active lode claims and 2 placer claims in the tract (Dicken 

and San Juan, 2016).

Polymetallic replacement deposits occur mostly in the 

eastern part of the tract and formed proximal to intrusive stocks 

and dikes. The deposits developed in recrystallized, bleached, 

and silicified dolomitic limestone along faults and bedding 

planes at the Aura King Ag-Pb-(Au-Cu-Zn), Aura Queen 

Au-(Ag-Cu-Pb-Zn), Big Four Pb-Ag-(Cu-Au-Sb-Zn), Blue 

Jacket Ag-Pb-Zn-(Au-Cu-Sb-As), Burns Pb-Zn-Ag-(Au-Sb), 

California Ag-Pb-(Zn-Au), Columbia Ag-Au-Pb-(Zn), and 

Infidel Ag-Pb replacement deposits, and at the Golden Eagle 

Au-Pb skarn. Sulfide, silicate, carbonate, and oxide minerals 

in replacement deposits include pyrite, galena, chalcopyrite, 

sphalerite, tetrahedrite, quartz, calcite, silica, and iron oxides. 

At the Golden Eagle skarn, calc-silicates with disseminated 

pyrite and chalcopyrite are cut by barren white quartz veins. A 

medium-grained strongly propylitized (epidote-chlorite-albite) 

diorite is associated with skarn mineralization (Smith, 1976; 

LaPointe and others, 1991).

Tract INPR04_pmv, Blue Jacket Polymetallic Vein—There 

is high (H) potential, with certainty level C, for intrusion-related 

silver-lead-(gold-copper-antimony-zinc) and gold-silver-(leadcopper) polymetallic vein deposits in the Aura and Edgemont 

districts 20 km southwest of Mountain City, Elko County, 

Nevada (LaPointe and others, 1991; fig. 31E; appendix 2). The 

geology, regional geochemical, geophysical, and remote-sensing 

data that characterize the tract are described in report section 

“Tract INPR04_pmr, Blue Jacket Polymetallic Replacement.” 

Polymetallic vein deposits occur in association with 

polymetallic carbonate replacement deposits where proximal 

to intrusive stocks and dikes. Polymetallic vein deposits in 

the Aura district are commonly hosted by faults in silicified 

dolomitic limestone at the Aura King Ag-Pb-(Au-Cu-Zn), 

Big Four Pb-Ag-(Cu-Au-Sb-Zn), Blue Jacket Ag-Pb-Zn-(AuCu-Sb-As), California Ag-Pb-(Zn-Au), Columbia Ag-Au-Pb-

(Zn), Infidel Ag-Pb, and Tiger Lode Ag-(Pb-Zn-Cu) veins and 

associated replacement systems, and the Polaris Ag-(Au-Cu-Pb) 

vein (LaPointe and others, 1991; Sherlock and others, 1996).

In contrast to the silver-rich carbonate-hosted veins in the 

Aura district, quartzite- and shale-hosted veins in the Edgemont 

district are gold rich. Polymetallic vein deposits include the Big 

Bob Au-(Ag), Bull Run Au-Ag-(Pb), Echo Canyon Au-Pb-(AgCu-Zn), Lucky Boy Au-(Ag-Pb), and Lucky Girl Au-(Ag-Cu-Pb) 

vein systems. Alteration selvages around these quartz veins consist 

of sericite and pyrite. Sulfides include pyrite, arsenopyrite, galena, 

and minor chalcopyrite. Polymetallic vein deposits in this district 

that are hosted by carbonate instead of quartzite and shale exhibit 

contrasting silver-rich mineralogy similar to that found in the Aura 

district. The Burns Pb-Zn-Ag-(Au-Sb) vein occurs in limestone, 

and the Nevada Zn-(Pb-Ag) vein occurs in the White Rock diorite 

stock near the contact with Ordovician limestone (Smith, 1976; 

LaPointe and others, 1991).
158 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

 Tract INPR04_Wv, Blue Jacket Tungsten Vein—There is 

moderate (M) potential, with certainty level B, for intrusionrelated tungsten vein deposits in the Aura and Edgemont 

districts 20 km southwest of Mountain City, Elko County, 

Nevada (LaPointe and others, 1991; fig. 31E; appendix 2). 

The geology, regional geochemical, geophysical, and remotesensing data that characterize the tract are described in 

report section “Tract INPR04_pmr, Blue Jacket Polymetallic 

Replacement.” 

A tungsten vein deposit and associated skarn occurrences are 

located close to the contact with one of the smaller White Rock 

stocks in the northwestern part of the tract. Here, a fault-vein is 

hosted by limestone at the Burns Scheelite Mine. Scheelite occurs 

in seams and disseminated in the quartz vein. A single shipment of 

6 short tons of ore in 1953 averaged 0.73 percent tungsten trioxide 

(WO3) (Smith, 1976; LaPointe and others, 1991).

Tract INPR05_pmv, Alder Polymetallic Vein—There 

is moderate (M) potential, with certainty level C, for 

polymetallic gold-silver vein deposits in the Alder district 

20 km west of Jarbidge, Elko County, Nevada (LaPointe and 

others, 1991; fig. 31F; appendix 2). The geology of the area 

is characterized by a deformed sequence of Lower Paleozoic 

carbonate and argillaceous rocks that have been intruded 

by the middle Cretaceous (120 Ma) granodiorite to quartz 

monzonite Coffeepot pluton (du Bray and Crafford, 2007). 

The Coffeepot pluton is cut by normal faults and is partly 

overlain by Miocene volcanic rocks (Coats, 1987; LaPointe 

and others, 1991; Crafford, 2007). 

The first discoveries in the Alder district were made in 

1869. Lode mining of silver-gold vein deposits continued 

intermittently from the early 1870s through the 1930s. Lode 

mining from 1916 through 1939 from the Clipper Alder, 

Pittsburg Silver, and Mohawk Mines yielded 53 oz of gold 

and 1,219 oz of silver. Precious-metal production has not 

been recorded from vein deposits since 1939 (Smith, 1976; 

LaPointe and others, 1991). 

The tract was delineated by a 3-km buffer around the 

Coffeepot pluton (Crawford, 2007). Soil and stream-sediment 

geochemistry in the tract is characterized by local moderately 

high to high concentrations (8 to 15 times background) 

of antimony, molybdenum, and uranium, and moderately 

high concentrations (4 to 7 times background) of silver, 

arsenic, beryllium, cadmium, iron, phosphorus, strontium, 

thorium, and vanadium (U.S. Geological Survey, 2016b). The 

Coffeepot pluton is well-imaged by magnetic high, and located 

over a gravity low (Day and others, 2016). Mines in the tract 

occur in association with a distinct U/Th high, as reflected by 

radiometric measurements (Day and others, 2016). A northsouth-trending, 4-km long zone of advanced argillic and ferric 

iron in the Coffeepot pluton between the Garnet and Little Joe 

Mines is interpreted from ASTER satellite imagery (Rockwell 

and others, 2015). South of the pluton, well-developed 

advanced argillic, ferric iron, and argillic alteration occurs in 

Proterozoic quartzite-dominated units and Quaternary glacial 

deposits. In the northern part of the pluton, an argillic and 

widespread sericite and ferric iron alteration zone occurs 2 km 

west-southwest and around the Red Ledge Claims prospect. 

An additional 500- by 200-m zone of advanced argillic, 

argillic, sericitic, and hydrous silica alteration is located at the 

Clipper Alder Mine. Previous assessments estimate that all or 

parts of this tract are favorable and prospective for intrusionrelated polymetallic deposits (Wallace and others, 2004; Parks 

and others, 2016). There are 74 active lode claims in the tract 

(Dicken and San Juan, 2016).

Precious metal-bearing polymetallic vein deposits occur at 

the Clipper Alder Au-(Ag-Pb-Cu-Fe), Mohawk Au-(Ag), Pittsburg 

Silver Ag-(Au), and Tennessee Gulch Au mines, and the Johnson 

Group Au prospect. Quartz-calcite veins with gold, pyrite, and 

minor argentiferous galena and other sulfides are common near 

and within the contact zone of the Coffeepot pluton, where they 

cut the Paleozoic rocks and the quartz monzonite. In several 

places, veins are adjacent to altered aplite and porphyry dikes and 

associated skarn (Smith, 1976; LaPointe and others, 1991).

Previous assessments that include all or parts of this tract 

assign favorable and prospective favorability for intrusionrelated polymetallic deposits (Wallace and others, 2004; Parks 

and others, 2016).

Tract INPR05_WMosk, Alder Tungsten-Molybdenum 

Skarn—There is high (H) potential, with certainty level D, for 

tungsten-molybdenum skarn deposits in the Alder district 20 km 

west of Jarbidge, Elko County, Nevada (LaPointe and others, 

1991; fig. 31F; appendix 2). The geology, regional geochemical, 

geophysical, and remote-sensing data that characterize the tract 

are described in report section “Tract INPR05_pmv, Alder 

Polymetallic Vein.”

Following discovery of tungsten in 1949, exploration 

in the district focused on scheelite- and molybdenite-bearing 

skarns. The Garnet Mine is the best developed and most 

productive skarn deposit in the district. Reserves in the 1950s 

were estimated at 224,000 short tons at 0.5 percent tungsten 

trioxide (WO3

), and 540,000 short tons at 0.4 percent tungsten 

trioxide (WO3) (LaPointe and others, 1991). However, only 

small quantities of tungsten were produced in 1970 and 1977. 

Between 1954 and 1956, the Batholith Mine produced 

1,000 short tons of tungsten ore averaging 0.5 percent to 

1.0 percent tungsten trioxide (WO3

). Tungsten ore was also 

shipped from the Coon Creek (Rowland) Mine in 1943 and 

from 1954 to 1956, yielding a total of 608 units of tungsten 

trioxide (WO3) (Stager and Tingley, 1988). The Little Joe 

Mine may have produced a few tons of sorted tungsten ore 

that contained 3 percent tungsten trioxide (WO3) from a 

narrow quartz vein (Smith, 1976).

Tungsten-molybdenum deposits in the Alder district occurs 

along the contact between deformed Paleozoic limestone and 

argillaceous rocks and the Coffeepot pluton. Dikes and sills 

intrude the sedimentary wall rocks along the contact. The principal 

tungsten-molybdenum skarns in the district occur at the Garnet, 

Little Joe, and Mohawk-Pittsburg Mines on the southwestern 

margin, and at the Batholith and Coon Creek Mines on the 

southeastern margin of the pluton (Smith, 1976; Sherlock and 

others, 1996; LaPointe and others, 1991). At the Garnet W-Mo-

(U-Cu-Bi) mine, garnet-epidote skarn is cut by an east-trending 
Mineral-Resource Potential 159

and clay-altered quartz monzonite dike. The skarn contains 

scheelite and molybdenite, and lesser amount of powellite, 

bismuthinite, and chalcopyrite. The skarn is cut by gray to white 

gold-, scheelite-, and molybdenite-bearing quartz veins. Uraninite 

(pitchblende) occurs in fault gouge. At the Little Joe W-(Mo-Cu) 

mine, skarn is cut by aplite dikes and veinlets of quartz and calcite. 

Scheelite occurs in the skarn and in tungsten-bearing quartz 

veinlets near the dikes. At the Batholith W-Mo and Conn Creek 

(Rowland) Cu-W-(Mo) mines, scheelite occurs with powellite and 

molybdenite in skarn at the contact between a quartz monzonite 

stock and limestone interbedded with shale and quartzite. At Coon 

Creek, chalcopyrite is more abundant. Garnet, epidote, calcite, 

and magnetite skarn is cut by quartz veins. Other tungsten skarns 

are located at the Apex W-(Mo), Chapin group W-(Mo), Copper 

Queen W-(Cu-Pb-Ag), Hot Springs Claims W, and Red Ledge 

Claims W prospects (Smith, 1976; LaPointe and others, 1991).

Tract INPR06_dd, Island Mountain Distal Disseminated 

Gold-Silver—There is high (H) potential, with certainty level D, 

for intrusion-related gold-silver, distal disseminated silver-gold 

deposits in the Island Mountain District southeast of Mountain 

City, Elko County, Nevada (LaPointe and others, 1991; fig. 31G; 

appendix 2). The geology of the area is characterized by deformed 

and faulted Paleozoic sedimentary rocks that are intruded by 

the Jurassic Island Mountain (Hammond Canyon) stock and 

Cretaceous Coffeepot quartz monzonite pluton on the west and 

north, respectively. These Paleozoic rocks and Mesozoic plutons 

are overlain by Eocene and Miocene volcanic and volcaniclastic 

strata. Northeast-striking faults cut the sedimentary and volcanic 

rocks and are displaced by younger northwest-striking faults. 

Quaternary alluvium covers parts of the area (Smith, 1976; Coats, 

1987; LaPointe and others, 1991; Crafford, 2007).

The tract was delineated by aggregating 3-km buffers 

around the centers of the Island Mountain and St. Elmo 

active exploration projects (Peatfield, 2004; Broili and others, 

2007; Fernette and others, 2016a). It excludes the contrasting 

mineralization style along the contact with the Coffeepot pluton 

in the northernmost part of the St. Elmo active exploration 

claim block, which is included in report section “Tract INPR05_

WMosk, Alder Tungsten-Molybdenum Skarn.”

In the Island Mountain project, soil and stream-sediment 

geochemistry in the tract is characterized by high concentrations 

(more than 16 times background) of cadmium; moderately high 

to high concentrations (8 to 15 times background) of antimony, 

arsenic, and uranium; and moderately high concentrations (4 to 

7 times background) of gold and molybdenum (U.S. Geological 

Survey, 2016b). The Island Mountain stock coincides with a 

local magnetic high that reflects the exposed intrusion as well 

as an internal gravity high. The area is cospatial with elevated 

potassium, uranium, and thorium concentrations, as reflected 

by thorium/potassium (Th/K) from radiometric measurements 

(Day and others, 2016). Advanced argillic alteration, argillic 

alteration, and ferric iron mainly along faults in Lower 

Paleozoic quartzite-dominated rocks is interpreted from ASTER 

satellite imagery (Rockwell and others, 2015). Also, small 

alteration zones occur in Paleozoic clastic and carbonate rocks 

and in the Island Mountain stock.

In the St. Elmo project, soil and stream-sediment 

geochemistry is characterized by moderately high 

concentrations (4 to 7 times background) of silver and 

cadmium (U.S. Geological Survey, 2016b). The St. Elmo 

project area is cospatial with elevated potassium, uranium, 

and thorium concentrations, as reflected by thorium/potassium 

(Th/K) from radiometric measurements, like those noted at the 

Island Mountain stock (Day and others, 2016). Well-developed 

advanced argillic, and argillic and ferric iron alteration 

northeast of the St. Elmo Mine and between the Diamond 

Jim and Rosebud Claims Mines is interpreted from ASTER 

satellite imagery (Rockwell and others, 2015). The alteration 

zones occur mainly in Lower Paleozoic quartzite.

Previous assessments estimate that all or parts of 

this tract are permissive for intrusion-related polymetallic 

replacement, porphyry copper, and skarn deposits (U.S. 

Geological Survey, 2001; Wallace and others, 2004; Parks and 

others, 2016). There are 186 active lode claims and 2 placer 

claims in the tract (Dicken and San Juan, 2016).

Distal disseminated gold-silver deposits in the Island 

Mountain district have been identified in two areas. The 

first gold-silver project occurs near the southwest contact of 

the Island Mountain stock (Peatfield, 2004), and the second 

project is located near the Diamond Jim and Rosebud Mines 

about 7 km to the east (Broili and others, 2007). The sedimenthosted style of gold-silver deposit is considered similar to 

Carlin-type gold deposits by the deposit owners. However, 

proximity to intrusions and association of base metal vein and 

skarn deposits with those intrusions suggests that the goldsilver deposit type is distal disseminated.

Deposits at the Island Mountain active exploration 

project are hosted by interbedded limestone and limy siltstone 

units of Permian age. These units are replaced by faultcontrolled limonitic bodies of jasperoid or massive silica. 

Disseminated gold and sulfide minerals occur mainly in some 

of these bodies, but is also found away from faults in favorable 

stratigraphy. Sedimentary units have been altered to skarn 

along the contact with the intrusion 100 to 200 m to the east. 

Contrasting bismuth-bearing silver and base-metal prospects 

occur in skarn and intrusion-hosted veins along the contact 

(Peatfield, 2004). 

Geochemical surveys at the Island Mountain project 

indicate anomalous gold, arsenic, antimony, and mercury 

concentrations. Magnetic surveys image the Island Mountain 

intrusion well, but also show a 500- by 1,000-m north-southtrending magnetic high over the distal disseminated gold 

target. Electrical surveys are roughly coincident but open to 

the north (Peatfield, 2004). Drill holes from several drilling 

programs estimate a current resource of 26.3 million short tons 

at 0.019 opt gold (Juhas and Hollenbeck, 2012).

Mineralization at the St. Elmo active exploration project 

is hosted by Cambrian to Ordovician quartzite, shale, and 

limestone rock succession that has been complexly faulted by 

Mesozoic (and possibly Paleozoic) thrust faults and northeast, 

north, and northwest-trending normal faults. These rocks 

have been intruded by the small Cretaceous Gold Creek 
160 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

hornblende-biotite quartz diorite intrusion exposed about 3 km 

west of the polymetallic vein at the St. Elmo Mine. Northeast 

of the St. Elmo Mine, fracture-controlled silica and jasperoid 

replacements are surrounded by strong bleaching, clay-sericite 

alteration, and iron-oxide staining. Jasperoids contain finegrained pyrite, and select samples contain as much as 5 g/t 

gold. A magnetic survey over the project area indicates two 

weak magnetic highs that may reflect buried intrusive bodies. 

At present, there are no available mineral-resource estimates 

for this early-stage exploration project (Broili and others, 

2007).

Tract INPR06_pmv, Island Mountain Polymetallic Vein 

and Skarn—There is high (H) potential, with certainty level 

C, for intrusion-related silver-lead (zinc-copper-antimonytungsten-gold) polymetallic veins and associated skarn 

deposits in the Island Mountain District southeast of Mountain 

City, Elko County, Nevada (LaPointe and others, 1991; 

fig. 31G; appendix 2). The geology, regional geochemical, 

geophysical, and remote-sensing data that characterize the 

tract are described in report section “Tract INPR06_dd, Island 

Mountain Distal Disseminated Gold-Silver.”

Silver-lead-copper-zinc-antimony veins in the Island 

Mountain district were discovered in 1869; however, mining 

in the area focused on placer gold between 1873 and 1901. 

About 40,000 oz of gold are reported to have been recovered 

from placers. Production from lode deposits was first recorded 

in 1934 from the Rosebud and Diamond Jim lead-(gold-silvercopper-zinc) vein deposits, but lead, silver, zinc, and copper 

production in the district occurred mostly between the 1950s 

and 1970s. Sporadic small-scale mining continued into the 

1980s. The Diamond Jim open-pit mine produced most of the 

ore in the district from 1954 and 1985 (Smith, 1976; LaPointe 

and others, 1991). 

Deposits in the Island Mountain district include Ag-Pb-

(Zn-Cu-Sb)-bearing polymetallic vein, and subordinate Sb-(W)-

dominated skarn deposits. Gold is variably present in both 

types of deposits. Quartz-calcite veins and local replacement 

bodies contain argentiferous galena, argentite, and minor 

stibnite, sphalerite, tetrahedrite, and tennantite (Smith, 1976; 

LaPointe and others, 1991). These veins also carry elevated 

concentrations of bismuth (Peatfield, 2004). Vein deposits in 

the district are represented by the Coleman Au-(Ag-Cu) and 

the Diamond Jim and Rosebud Pb-(Au-Ag-Cu-Zn) mines. The 

latter are located about 7 km east of the Island Mountain stock.

Ore in skarns commonly consists of pyrite, chalcopyrite, 

scheelite, and minor molybdenite. Skarns are closely 

associated with aplite dikes and cut by quartz-calcite veins. 

Skarn deposits include several occurrences along the edge 

of the Island Mountain stock, and the Gribble Sb-W-(Pb-Zn) 

mine located approximately 5 km northeast of the stock. 

Antimony was shipped in 1941 and 1951 from the Sb-W-

(Pb-Zn) vein and skarn deposit at the Gribble Mine. Between 

1952 and 1955, the Gribble Mine also produced tungsten 

trioxide (WO3

) (Smith, 1976; LaPointe and others, 1991).

Tract INPR07, Charleston—There is moderate (M) 

potential, with certainty level C, for intrusion-related 

copper-antimony-(gold-silver-zinc-lead) polymetallic vein 

deposits, in the Charleston District of Elko County, Nevada 

(LaPointe and others, 1991; fig. 31H; appendix 2). The geology 

of the area is characterized by highly deformed and locally 

recrystallized and hornfelsed Paleozoic sedimentary rocks that are 

intruded by the Jurassic Seventy Six Creek quartz monzonite stock 

(du Bray and Crafford, 2007). The stock and sedimentary rocks 

are cut by granitic, monzonitic, and dioritic dikes. These rocks 

are overlain by Eocene and Miocene volcanic and volcaniclastic 

strata, which are dissected by high-angle normal faults (Smith, 

1976; Coats, 1987; LaPointe and others, 1991; Ketner, 2005; 

Crafford, 2007).

Placer gold was discovered along Seventy Six Creek in 

1876. Mining activity continued into the 1930s, but placer 

production was limited. The most extensive workings along 

polymetallic veins in the district are those of the Prunty and 

Slattery Mines, which were most active between 1905 and 

1920. The Prunty Mine continued to be mined intermittently 

for its precious metals into the early 1980s. Production is also 

reported from the Black Warrior Au-Sb-(Ag-Cu-Pb), Carleton 

Tunnel Cu, Prunty Antimony Sb-Ag-(Cu-Au), Prunty Cu-Sb-

(Zn-Au-Ag-Pb-Bi), Rescue Cu-(Ag-Zn-Au-Sb-Bi), and Slattery 

Cu-(Ag-Pb) mines (Smith, 1976; LaPointe and others, 1991).

The tract was delineated by aggregating 3-km buffers 

around the Black Warrior, Carlton Tunnel, Prunty Antimony, 

Prunty, Rescue, and Slattery Mines (Fernette and others, 

2016a). The tract encompasses these mines and the Seventy 

Six Creek stock. Soil and stream-sediment geochemistry in 

the tract is characterized by high concentrations (more than 

16 times background) of cadmium, and moderately high 

concentrations (4 to 7 times background) of arsenic, barium, 

molybdenum, and strontium (U.S. Geological Survey, 2016b). 

The Seventy Six Creek stock is imaged by a magnetic high 

and located over a pronounced gravity low (Day and others, 

2016). The Charleston district is cospatial with elevated 

thorium/potassium (Th/K), as reflected by radiometric 

measurements (Day and others, 2016).

Well-developed advanced argillic, argillic, ferric iron 

and lesser sericite alteration in Proterozoic and in Paleozoic 

quartzite-dominated rocks is interpreted from ASTER satellite 

imagery (Rockwell and others, 2015). A 500- by 500- m 

advanced argillic, argillic, and ferric iron alteration zone is 

also present about 1 km north of the Charleston Tunnel Mine. 

Smaller advanced argillic and ferric iron alteration zones, 

based on interpretation of ASTER imagery, occur in the 

Seventy Six Creek intrusion.

Previous assessments estimate that all or parts of this tract 

are permissive for intrusion-related polymetallic replacement, 

porphyry copper, and skarn deposits (U.S. Geological Survey, 

2001; Wallace and others, 2004; Parks and others, 2016). There 

are 122 active lode claims and 3 placer claims in the tract 

(Dicken and San Juan, 2016).

Polymetallic veins in the Charleston district are associated 

with hydrothermally altered and sulfide-bearing granitic, 

monzonitic, and dioritic dikes that intrude quartzite, shale, and 

limestone units. Quartz-calcite-(barite) veins contain pyrite, 
Mineral-Resource Potential 161

arsenopyrite, pyrrhotite, chalcopyrite, sphalerite, galena, and 

stibnite. Silver and gold, and elevated concentrations of bismuth 

and selenium are also present (Smith, 1976; LaPointe and 

others, 1991).

Tract INPR08_WMosk, Elk Mountain Tungsten-Molybdenum 

Skarn—There is moderate (M) potential, with certainty levelC,

for intrusion-related tungsten-molybdenum skarn deposits in 

the Elk Mountain district 30 km northwest of Contact, Elko 

County, Nevada (LaPointe and others, 1991; fig. 31I; appendix 2). 

The geology of the area is characterized by lower Paleozoic 

sedimentary rocks that are intruded by Late Cretaceous White 

Elephant Butte (Elk Mountain) granodiorite to quartz monzonite 

stock and associated late dikes. Paleozoic carbonate rocks near 

the contact have been locally altered to skarn. Paleozoic rocks 

are partly covered by Eocene tuffs and Miocene rhyolites that are 

cut by northeast- and younger northwest-trending normal faults 

(Smith, 1976; Coats, 1987; LaPointe and others, 1991; Crafford, 

2007).

The tract was delineated by placing a 3-km buffer around 

mines and prospects, and by clipping the buffer to the west and 

south where the intrusion is in fault contact with thick Miocene 

and younger volcanic and volcaniclastic units (Fernette and 

others, 2016a). The tract encompasses the intrusion.

Soil and stream-sediment geochemistry in the tract is 

characterized by local, moderately high to high concentrations 

(8 to 15 times background) of molybdenum, and moderately 

high concentrations (4 to 7 times background) of cadmium, 

magnesium, and strontium (U.S. Geological Survey, 2016b). 

The granodiorite stock is prominently reflected by an isolated 

magnetic high and is cospatial with a gravity high and elevated 

concentrations of thorium and potassium (high thorium-potassium 

ratios) as reflected by radiometric measurements (Day and others, 

2016). A small northeast-trending zone of advanced argillic 

alteration, ferric iron, and argillic alteration in postmineralization 

Eocene rhyolitic strata is interpreted from ASTER satellite 

imagery (Rockwell and others, 2015). Previous assessments 

estimate that all or parts of this tract are permissive for intrusionrelated polymetallic replacement deposits and porphyry copper 

deposits (U.S. Geological Survey, 2001; Wallace and others, 2004; 

Parks and others, 2016). There are no active lode claims or placer 

claims in the tract (Dicken and San Juan, 2016).

Tungsten-molybdenum skarn deposits in the district are 

represented by the Pyramid (Robinette) W-Mo-(Au-Cu) mine 

and other tungsten-bearing occurrences around the southern 

contact of the intrusion. Garnet-dominated skarns are proximal 

to late intrusive dikes that cut granodiorite, limestone, and 

quartzite. The Pyramid Mine was the only productive skarn in 

the district. Scheelite and molybdenite ores locally contained as 

much as 0.25 percent tungsten trioxided (WO3

) and 0.2 percent 

MoS2. About 400 short tons of tungsten ore averaging 0.5 

percent tungsten trioxide (WO3) were mined and milled from the 

property in 1957 and 1958 (Sherlock and others, 1996; Smith, 

1976; Stager and Tingley, 1988; La Pointe and others, 1991).

Tract INPR08_Cusk, Elk Mountain Copper Skarn—There 

is moderate (M) potential, with certainty level C, for intrusionrelated copper skarn deposits in the Elk Mountain district 30 km 

northwest of Contact, Elko County, Nevada (LaPointe and others, 

1991; fig. 31I; appendix 2). The geology, regional geochemical, 

geophysical, and remote-sensing data that characterize the tract are 

described in report section “Tract INPR08_WMosk, Elk Mountain 

Tungsten-Molybdenum Skarn.”

Copper mineralization was first noted in the district as 

early as 1890, and little mining occurred until the 1940s and 

1950s. During the late 1960s, several companies explored for 

copper (Smith, 1976; LaPointe and others, 1991).

Copper skarn mineralization in the district is represented 

by the Valdez Au-Cu-(Ag-Pb) mine, and the Red Elephant, 

Estes Cu, and Jim Claims Cu-(Zn) prospects located along 

the eastern contact of the intrusion. The Valdez Mine consists 

of copper- and scheelite-bearing epidote skarn, faultcontrolled jasperoid after limestone, and a quartz vein. The 

Red Elephant skarn consists of a 4.5-meter-thick ore body 

containing malachite, azurite, chrysocolla, chalcopyrite, and 

bornite in a gangue of silicified or garnetized limestone. Skarn 

mineralization at the Jim Claims prospect is associated with a 

porphyritic quartz monzonite (Schrader, 1912; Smith, 1976; 

LaPointe and others, 1991).

Tract INPR08_pmv, Elk Mountain Polymetallic Vein—

There is moderate (M) potential, with certainty level C, 

for intrusion-related polymetallic vein deposits in the Elk 

Mountain district 30 km northwest of Contact, Elko County, 

Nevada (LaPointe and others, 1991; fig. 31I; appendix 2). 

The geology, regional geochemical, geophysical, and remotesensing data that characterize the tract are described in report 

section “Tract INPR08_WMosk, Elk Mountain TungstenMolybdenum Skarn.”

Polymetallic vein deposits in the district are represented 

by the Austean Cu-Au mine and the O’Neil Cu prospect 

located respectively along the northern and southern contacts 

of the intrusion. Quartz-calcite veins are commonly associated 

with steep brecciated and silicified fault zones. The veins 

are as much as 2 m wide and contain copper oxide minerals, 

native copper, stibnite, argentite, and gold (Schrader, 1912; 

Smith, 1976; LaPointe and others, 1991).

Tract INPR09_pCu, Contact Porphyry Copper—There 

is high (H) potential, with certainty level D, for copper-

(molybdenum-gold) porphyry and associated porphyry-related 

skarn deposits in the Contact district centered on the town of 

Contact, Elko County, Nevada (LaPointe and others, 1991; 

fig.31J; appendix 2). The geology of the area is characterized 

by a deformed sequence of Carboniferous quartzite, shale, and 

limestone units that have been intruded by the Jurassic Contact 

allanite-bearing biotite-hornblende granodioritic pluton (156Ma;

du Bray and Crafford, 2007). The Contact pluton consists of three 

main intrusions that are exposed just west and east, and 15km east

of the town of Contact. Sedimentary rocks are variably altered 

to hornfels and skarn within 600 m of the contact with these 

intrusions. Steeply dipping northeast, northwest, and contactparallel faults cut intrusive and sedimentary rocks. Faults trending 

N. 40°–70° E. and N. 40° W. commonly host potassically altered 

and mineralized quartz monzonite, quartz syenite, syenite, and 

alaskite porphyry dikes. The dikes are as wide as 60 m and as 
162 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

long as 8 km. Paleozoic and Mesozoic rocks are unconformably 

overlain by Miocene volcanic and volcaniclastic strata and 

Pliocene lacustrine deposits (Schrader, 1937; Coats, 1987; 

LaPointe and others, 1991; Crafford, 2007). 

Copper mining in the Contact district started in the late 

1870s. Largely unsuccessful efforts in consolidating and 

developing mining operations occurred between the 1880s 

and 1905. Mining activity in the district revived after 1905, 

and production from several mines, most notably from the 

Nevada Belleview, peaked during the first and second world 

wars. Operations continued through to 1957. Little production 

was recorded in the district from 1958 to 1969, but interest 

was renewed in the 1970s with several exploration projects for 

porphyry copper-molybdenum targets (Smith, 1976; LaPointe 

and others, 1991). Exploration efforts have continued until 

present, with the last drilling campaign occurring in 2012 

(Choquette and others, 2013).

The most productive deposits of the district have been along 

the northern contact zone of the western intrusion, where the 

Contact porphyry copper active exploration project is located 

(Long and others, 1998; Fernette and others, 2016a). The deposit 

has an estimated resource of 429 million short tons at 0.19 percent 

copper (0.07 percent copper cutoff grade; Choquette and others, 

2013). Active exploration projects are also evaluating copper 

oxide targets around the Copper Shield Cu-(Mo) and New York 

Cu mines within the intrusion about 1 km south of the contact 

(Choquette and others, 2013; Fernette and others, 2016a). 

The tract was delineated by aggregating 3-km buffers 

around mines and exploration projects (Fernette and others, 

2016a). Soil and stream-sediment geochemistry in the tract 

is characterized by high concentrations (more than 16 times 

background) of bismuth, copper, and lead, moderately 

high to high concentrations (8 to 15 times background) of 

antimony, calcium, and molybdenum, and moderately high 

concentrations (4 to 7 times background) of arsenic, cadmium, 

gold, magnesium, nickel, phosphorus, strontium, thorium, and 

zinc (U.S. Geological Survey, 2016b). The Contact pluton is 

prominently reflected by isolated magnetic and gravity highs, 

and by elevated concentrations of thorium and potassium, 

as reflected by radiometric measurements (Day and others, 

2016). A broad area of sericite and ferric iron alteration on the 

western intrusion is interpreted from ASTER satellite imagery 

(Rockwell and others, 2015). Previous assessments estimate 

that all or parts of this tract are permissive for intrusion-related 

polymetallic replacement, skarn, and porphyry copper deposits 

(U.S. Geological Survey, 2001; Wallace and others, 2004; 

Parks and others, 2016). There are 567 active lode claims and 

8 placer claims in the tract (Dicken and San Juan, 2016).

Copper deposits along the contact (skarn) and within 

the intrusion (vein) are associated with alaskite, quartz 

monzonite, and quartz syenite porphyry dikes that have been 

recognized in all three intrusions. In the northern part of the 

west intrusion, copper-molybdenum-precious metal porphyryrelated deposits are reported from the Contact and Copper 

Ridge active exploration projects; the Bonanza, Copper King, 

Copper Shield, Ivy Wilson, Junction, and Nevada-Bellevue 

Mines; and the Archie, Florence, Salt Lake, Yellow Girl, 

and White Elephant prospects. Cu-(Au-Ag-Mo) quartz veins 

adjacent to porphyry dikes are as large as 3-m wide and 3-km 

long. They consist of vitreous quartz with chalcopyrite and 

bornite, and lesser galena, sphalerite, molybdenite, argentite, 

and gold. Where hosted by the intrusion, veins exhibit potassic 

and sericitic alteration halos and disseminated copper minerals 

that extend hundreds of feet into the wall rock (Smith, 1976; 

LaPointe and others, 1991). Where hosted by carbonate units, 

copper sulfides and oxides occur in a gangue of garnet, axinite, 

epidote, calcite, quartz, actinolite, diopside, iron oxides, 

and chloropal (Schrader, 1937; LaPointe and others, 1991). 

Carbonate replacement deposits associated with porphyry 

dikes include the Hickey Pb-Ag-(Cu-Zn-Au) and Lena 

Shaft Cu mines, and Detweiler Cu prospect. The most distal 

Hickey replacement deposit is located about 1 km north of the 

intrusion contact.

Porphyry-related vein and skarn systems around the 

northern contact of the east intrusion occur at the O’Connell 

Group Ag-(Mo-Cu) skarn mine and the Clark Group 

Cu-(Au-Ag) vein prospect. Along the southern contact zone of 

the east intrusion, veins and skarns associated with porphyry 

dikes include the Chinaman Cu, High Ore Cu-(Ag), Johnson 

Cu-Ag-(Au-Mo), and Silk Worm Pb-Zn-(Cu-Mo-Au) vein, 

and the Blanchard Cu-(Au-Ag-Mo) skarn and War Eagle 

Cu-Ag-(Au-Pb-Zn-Mo) replacement mines (Schrader, 1937; 

Smith, 1976; LaPointe and others, 1991). The Silk Worm 

vein is located about 9 km south of the exposed intrusion 

contact. Four parallel veins associated with pervasively altered 

porphyry dikes also occur at the Toano Cu-(Fe) prospect. This 

prospect is located on the intrusion 15 km east of the town of 

Contact (LaPointe and others, 1991). 

Tract INPR09_Cusk, Contact Copper Skarn—There 

is high (H) potential, with certainty level D, for intrusionrelated copper-(gold-silver) skarn deposits in the Contact 

district centered on the town of Contact, Elko County, 

Nevada (LaPointe and others, 1991; fig. 31J; appendix 2). 

The geology, regional geochemical, geophysical, and remotesensing data that characterize the tract are described in report 

section “Tract INPR09_pCu, Contact Porphyry Copper.”

In the northern part of the western intrusion, copper 

skarn deposits occur along the contact with equigranular 

granodiorite and associated dikes. Deposits include the Alice 

Cu-(Au-Ag-Mo-Fe), Brooklin Cu-(Au-Ag), Green Monster 

Cu-(Au-Ag), Old Abe Cu, Rattler Cu-(Ag-Au), and Silver 

Circle Cu-Ag-(Pb-Au) mines, and Bryan Cu-(Ag-Au) and 

Standard Group Cu prospects. The Boston Cu-(Au-Ag) skarn 

is the only one reported in the northern part of the eastern 

intrusion (LaPointe and others, 1991). Production from these 

skarns was small (Smith, 1976).

Tract INPR09_Wsk, Contact Tungsten Skarn—There is 

moderate (M) potential, with certainty level C, for intrusionrelated tungsten skarn deposits in the Contact district centered 

on the town of Contact, Elko County, Nevada (LaPointe and 

others, 1991; fig. 31J; appendix 2). The geology, regional 

geochemical, geophysical, and remote-sensing data that 
Mineral-Resource Potential 163

characterize the tract are described in report section “Tract 

INPR09_pCu, Contact Porphyry Copper.”

Tungsten skarn mineralization occurs only in the southern 

part of the eastern intrusion. At the Tunnel Mine, scheelitebearing skarn occurs at the contact of the granodioritic 

intrusion with limestone, dolomite, and shale. The mine 

produced 210 short tons of ore at 0.6 percent tungsten trioxide 

(WO3) in 1954 and 1955 (Smith, 1976; Sherlock and others, 

1996). At the Hice W-Pb-Ag-(Au-barite) prospect located 

about 3 km south of the contact with the intrusion, a breccia 

composed of Paleozoic wall rock clasts is cemented by jasper, 

barite, and quartz. Ore consists of lead, gold, and silver 

(LaPointe and others, 1991).

Tract INPR09_pmv, Contact Polymetallic Vein—

There is moderate (M) potential, with certainty level C, for 

intrusion-related polymetallic vein deposits in the Contact 

district centered on the town of Contact, Elko County, 

Nevada (LaPointe and others, 1991; fig. 31J; appendix 2). 

The geology, regional geochemical, geophysical, and remotesensing data that characterize the tract are described in report 

section “Tract INPR09_pCu, Contact Porphyry Copper.”

In the northern part of the western intrusion, Cu-(Au-Ag) 

veins are hosted by the intrusion and sedimentary wall rocks 

around the contact. Vein deposits are represented in the Allen, 

Antelope, Blue Bird, Empire, Jules Verne, Mammoth, Marshall, 

New York, and Palo Alto Mines. In the southern part of the eastern 

intrusion, polymetallic veins occur at the Arizona Cu-Au-(Ag), 

Hanks-Miller Cu-(Au-Ag-Ba), Silver King Pb-Ag-Cu-Zn-

(Au-Mn), Silver Star Pb-Ag-(Au-Cu), and Vulcan Ag-(Cu-Pb-ZnBa-Au) mines. The Arizona and Hanks Miller veins are located 

at the contact, whereas the Silver King and Silver Star Mines 

are located 5 km south of the exposed contact of the pluton. The 

Vulcan Mine is located about 2 km south of the contact. The 

Copper Button Cu-(Au-Ag) prospect is the only prospect in the 

northern part of the eastern intrusion (Smith, 1976; LaPointe and 

others, 1991).

Tract INPR10, Delano—There is high (H) potential, 

with certainty level D, for intrusion-related lead-silver-zinc 

polymetallic replacement deposits in the northern part of 

the Delano district, Elko County, Nevada (LaPointe and 

others, 1991; fig. 31K; appendix 2). The geology of the area 

is characterized by west-dipping Permian sedimentary rocks 

that are cut by faults with attitudes parallel and at high angles 

to bedding (LaPointe and others, 1991). Paleozoic rocks are 

overlain unconformably by Miocene volcanic and Pliocene 

volcaniclastic strata (Crafford, 2007).

The Delano district was first identified in 1872, and 

production was first recorded from the Cleveland Mine in 

1908. Production in the district was mainly from the Delano 

and Cleveland Mines every year from 1917 through 1966 

(Smith, 1976). During that time period, 1.5 million oz of 

silver, 333 oz of gold, 22 million lbs of lead, 1.3 million lbs 

of zinc, and 168,000 lbs of copper were produced (Long and 

others, 1998). Since then, production has been intermittent. 

Exploration at the Delano and Cleveland Mines in the 1980s 

identified a resource of approximately 240,000 short tons 

averaging 6.43 opt silver, 5.6 percent lead, and 3.8 percent 

zinc with minor values in copper and gold (LaPointe and 

others, 1991).

The tract was delineated by aggregating 3-km buffers 

around the Cleveland, Delano, Gold Note, and 86 Mines. Soil 

and stream-sediment geochemistry in the area is characterized 

by moderately high concentrations (4 to 7 times background) 

of cadmium and molybdenum (U.S. Geological Survey, 

2016b). The tract is located along the margin of a gravity low. 

As reflected by radiometric measurements, the tract occurs 

on the margin of a thorium/potassium (Th/K) high (Day and 

others, 2016). Small, isolated zones of advanced argillic and 

minor ferric iron alteration in Paleozoic sedimentary rocks 

around the Delano and Cleveland Mines are interpreted from 

ASTER satellite imagery (Rockwell and others, 2015).

Previous assessments estimate that all or parts of 

this tract are permissive for intrusion-related polymetallic 

replacement, skarn, and porphyry copper deposits (U.S. 

Geological Survey, 2001; Parks and others, 2016). The mines 

are inactive at present (Fernette and others, 2016a). However, 

there are 105 active lode claims in the tract (Dicken and San 

Juan, 2016).

Polymetallic replacement deposits are represented by 

the Delano Pb-Ag-Zn-(Cu-Au-Sb), Cleveland Zn-Pb-CuAg-(Sb-Au), Gold Note Pb-Zn-Ag-(Au-Cu-Sb), and 86 

Ag-Pb mines. At these mines, mixed oxide-sulfide cerussite, 

galena, bindheimite, and minor anglesite, sphalerite, argentite, 

tetrahedrite, and malachite occur in a gangue of silica-jasper. 

At the Cleveland and Delano Mines, replacement mantos 

occur along two parallel limestone beds that are separated by 

a partly silicified dolomite. The upper manto is located along a 

limestone-dolomite contact, and the lower manto occurs along 

a limestone-sandstone contact. In the larger upper manto, ore 

shoots were as much as 6-ft thick, 125-ft long, and were mined 

450 ft downdip in the Cleveland Mine, and 1,700 ft downdip in 

the Delano Mine (LaPointe and others, 1991).

Subeconomic cassiterite quartz veins healed with 

chalcedony occur alongside replacement mineralization at 

some mines. Their relationship to the polymetallic replacement 

deposits in the district is unclear. Tin mineralization is likely 

associated with Miocene rhyolite porphyry dikes exposed in the 

area (Slack, 1972; Smith, 1976; LaPointe and others, 1991).

Tract INPR11, Indian Springs—There is high (H) 

potential, with certainty level D, for intrusion-related tungsten 

(molybdenum) greisen deposits in the southern part of the 

Delano district, 45 km north of Montello, Elko County, 

Nevada (LaPointe and others, 1991; fig. 31L; appendix 2). 

The geology of the area is characterized by folded and thrustfaulted Permian sedimentary rocks that are intruded by the 

Lower Cretaceous Indian Springs quartz monzonite stock. 

Rocks at the contact are locally altered to garnet-diopsideepidote skarn and cut by quartz monzonite and granite 

porphyry dikes (Slack, 1972). Paleozoic rocks surrounding 

the stock are unconformably covered by Miocene volcanic 

and Pliocene volcaniclastic strata (Coats, 1987; LaPointe and 

others, 1991; Crafford, 2007). 
164 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Tungsten exploration in the area resulted in discovery of 

the Indian Springs deposit in 1969. By the 1980s, 12,500 short 

tons of ore averaging 0.25 percent tungsten trioxide (WO3) had 

been mined at Indian Springs (LaPointe and others, 1991). The 

current indicated and inferred resource stands at 19 million short 

tons at 0.17 percent tungsten trioxide (WO3) (0.10 percent WO3

cutoff grade; SRK Consulting, 2007).

The tract was delineated by aggregating 3-km buffers 

around the Indian Springs deposit and Mitchell mine (Fernette 

and others, 2016a). The tract encompasses the Indian Springs 

stock. Soil and stream-sediment geochemistry in the tract is 

characterized by moderately high concentrations (4 to 7 times 

background) of cadmium and molybdenum (U.S. Geological 

Survey, 2016b). The tract is located along the margin of a 

broad gravity high, and elevated thorium and potassium 

concentrations as reflected by radiometric measurements 

(Day and others, 2016). Interpreted ASTER satellite imagery 

(Rockwell and others, 2015) shows an area of advanced 

argillic alteration and ferric iron about 1 km north of Indian 

Springs.

Previous assessments estimate that all or parts of this tract 

are permissive for intrusion-related polymetallic replacement, 

skarn, and porphyry copper deposits (U.S. Geological Survey, 

2001; Parks and others, 2016). There are 45 active lode claims 

in the tract (Dicken and San Juan, 2016).

The Indian Springs W-Mo deposit consists of quartztopaz-muscovite-fluorite greisen veins and stockworks that 

are related to northeast-trending late quartz monzonite and 

granite porphyry dikes on the eastern edge of the 135 Ma 

Indian Springs stock (Slack, 1972). Ore minerals include 

scheelite, powellite, pyrite, magnetite, molybdenite, and 

minor chalcopyrite. Greisen veins exhibit potassium-silicate 

and intense sericite and clay alteration envelopes that spread 

out over a 2,000- by 3,000-ft surface area (LaPointe and 

others, 1991; SRK Consulting, 2007). Scheelite also occurs in 

associated W-(Mo-Cu-Zn) skarn on the southeastern edge of 

the stock, and in an Ag-Cu-W quartz vein at the Mitchell Mine 

on the northwestern edge of the stock. A newly-identified zone 

of anomalous gold values in rock chip and soil samples occurs 

about 500 m to the east of the Indian Springs deposit (Fernette 

and others, 2016a).

Tract INPR12, Gold Basin—There is moderate (M) 

potential, with certainty level B, for intrusion-related 

gold-(silver-copper) polymetallic veins in the Gold Basin 

(Rowland) district, Elko County, Nevada (LaPointe and 

others, 1991; fig. 31M; appendix 2). The geology of the area is 

characterized by steeply dipping Cambrian to Pennsylvanian 

limestone, schist, argillite, and phyllite. These rocks are cut 

by several northeast-trending thrust faults which generally 

parallel the strike of the beds, and by steeply dipping northnorthwest and northeast-striking normal faults. To the south, 

Paleozoic rocks are intruded by the Cretaceous (73 Ma; du 

Bray and Crafford, 2007) Deep Creek quartz monzonite stock. 

Contact metamorphism developed adjacent to the stock and 

produced hornfels and marble, but no significant skarn. These 

Paleozoic and Mesozoic rocks are partially overlain by Eocene 

andesite flows and are more extensively covered by Miocene 

rhyolite tuffs (Smith, 1976; Coats, 1987; LaPointe and others, 

1991; Crafford, 2007).

Small amounts of gold-silver ore with byproduct copper 

were produced intermittently from 1930 through 1940, mainly 

from the Bruneau Mine. Ore from the Bruneau and Mendive veins 

is reported to have had grades of 0.30 opt gold and 0.68 opt silver. 

No production has been reported from the district since 1941 

(Smith, 1976; LaPointe and others, 1991).

The tract was delineated by aggregating 3-km buffers 

around mines and prospects (Fernette and others, 2016a). Soil 

and stream-sediment geochemistry in the tract is characterized 

by high concentrations (more than 16 times background) of tin, 

and moderate to high concentrations (8 to 15 times background) 

of antimony, cadmium, and molybdenum (U.S. Geological 

Survey, 2016b). The tract is, in part, cospatial with an isolated 

magnetic low, and at the tract northern margin, a broad gravity 

low. Elevated uranium, thorium, and potassium concentrations, 

as reflected by radiometric measurements, occur in the tract 

(Day and others, 2016). An east-northeast-trending zone of 

advanced argillic alteration and ferric iron, and argillic alteration 

along the western margin of the Deer Creek stock is interpreted 

from ASTER satellite imagery (Rockwell and others, 2015). No 

prospects are known in this area.

Previous assessments estimate that all or parts of this tract are 

permissive for intrusion-related polymetallic replacement, skarn, 

and porphyry copper deposits (U.S. Geological Survey, 2001; 

Wallace and others, 2004; Parks and others, 2016). There are 5 

active lode claims in the tract (Dicken and San Juan, 2016).

Deposits in the area are represented by fissure veins. 

These occur at the Bruneau (Elko) Au-(Ag-Cu) and Deep 

Creek Au mines, and the Bearpaw Mountain Au, Mendive 

Au-(Ag-Cu), and Taylor Creek Au-(Ag) prospects. The Deep 

Creek Mine and Bearpaw Mountain prospect are located 

closest to the Deep Creek stock, but their relation to the 

intrusion is not documented (Smith, 1976; LaPointe and 

others, 1991; Fernette and others, 2016a).

Tract INPR13, Texas Canyon—There is moderate (M) 

potential, with certainty level C, for distal disseminated 

gold-silver deposits and associated silver-gold-bearing 

polymetallic vein deposits located about 80 km northeast of 

Wells in Elko County, Nevada (LaPointe and others, 1991; 

fig. 31N; appendix 2). The geology of the area is characterized 

by Permian carbonate and clastic rocks that were deformed 

and mildly metamorphosed in Mesozoic time. Both Jurassic 

and Cretaceous granitic rocks intrude the sedimentary rocks 

in nearby areas. Much of the area is covered by relatively 

thin sequences of Miocene volcanic rocks, some of which are 

reported to include quartz-latite subvolcanic intrusions (Coats, 

1987; Crawford, 2007).

The tract was delineated by aggregating 3-km buffers 

around the Rock Springs, Golden Trail, and Texas Canyon 

(including the Prince mine) active exploration projects 

(Fernette and others, 2016a). Soil and stream-sediment 

geochemistry around the Texas Canyon and Golden Trail 

projects is characterized by moderately high to high 
Mineral-Resource Potential 165

concentrations (8 to 15 times background) of molybdenum 

and moderately high concentrations (4 to 7 times background) 

of gold and cadmium. Soil and stream-sediment geochemistry 

around the Rock Springs project is characterized by 

moderately high concentrations (8 to 15 times background) 

of molybdenum (U.S. Geological Survey, 2016b). Weak 

positive regional magnetic anomalies occur east of the Texas 

Canyon and south of the Golden Trail projects. The tract area 

is otherwise cospatial with a regional gravity low (Day and 

others, 2016), and elevated concentrations of uranium and 

thorium (Texas Canyon) and potassium and thorium (Golden 

Trail), as reflected by radiometric measurements (Day and 

others, 2016).

A 100- by 500-m advanced argillic and ferric iron 

alteration zone in Paleozoic rocks 500 m south of the Prince 

Mine is interpreted from ASTER satellite imagery (Rockwell 

and others, 2015). Ferrous or coarse-grained ferric iron is well 

developed in Miocene volcanic rocks to the west. Argillic 

and ferric iron alteration are also present in Paleozoic rocks at 

Golden Trail.

Previous assessments estimate that all or parts of this 

tract are permissive for intrusion-related polymetallic deposits 

(Wallace and others, 2004; Parks and others, 2016). There 

are 164 active lode claims in the tract (Dicken and San Juan, 

2016).

Gold occurs at the Golden Trail project, the Texas 

Canyon project, and the Rock Springs property (Capps, 

2012; Capps and others, 2015; Western Pacific Resources 

Corp., 2016). Although the companies that have explored 

these properties since the 1970s often characterize the 

mineralization as “Carlin-type,” we believe the geology, 

alteration, and mineralogy of the veins indicate they are 

they are related to nearby but largely unexposed Mesozoic 

intrusions.

At the Golden Trail project, gold occurs in faultcontrolled quartz-carbonate-clay-white mica veins, and 

adjacent silica replacements, iron oxide-rich breccias, and 

jasperoids. These are hosted within a broad zone of hornfels 

and Zn-(Pb-Cu)-bearing skarn, and more distally in decalcified 

and dolomitized limestone. Results from geochemical rockchip sampling indicate that anomalous gold is associated 

with elevated silver, arsenic, antimony, and thallium values. 

Gold values above 20 part per billion (ppb) are common 

with several samples assaying above 9 ppm gold. Part of the 

Golden Trail project was explored and drilled as a porphyry 

molybdenum target in the 1970s (Capps, 2012). Several 

granitic/monzonitic hypabyssal intrusive intercepts are 

reported in drill logs (Capps and others, 2015). 

The characteristics of gold mineralization at the Texas 

Canyon project are comparable to those at the Golden Trail 

project. At Texas Canyon, however, a sulfide-bearing coarsegrained granitic intrusion is exposed at the surface. Gold in 

veins and adjacent breccia and silica replacement zones is 

associated with elevated antimony, arsenic, lead, silver, zinc, 

and local mercury, molybdenum, and copper values. At the 

Prince Mine, parallel veins extend northeasterly to the central 

Texas Canyon claim area. Vein gangue mineralogy includes 

several generations of quartz, sericite, calcite, and dolomite. 

Pseudomorphs after sulfides suggest the former presence of 

pyrite, chalcopyrite, and stibnite. The Prince Mine is reported 

to also contain anomalous uranium values (Capps, 2012).

At the Rock Springs property, the main area of gold deposits 

occur along two parallel ridges that trend N. 60° E. Surface 

sampling in 1987–89 of structurally controlled jasperoids in both 

ridges returned values as high as 0.055 opt (1.88 g/t) gold and 

16.1 opt (551 g/t) silver, 750 ppm arsenic, 0.99 percent antimony, 

and 32 ppm mercury. Recent surface rock chip samples returned 

values as high as 0.04 opt (1.38 g/t) gold, 8.7 opt (300 g/t) silver, 

1.7 percent lead, and 2.0 percent zinc. Quartz veins along these 

ridges contain stibnite, stibiconite, and local pyrite and barite 

(Western Pacific Resources Corp., 2016).

An additional exploration project is reported at Gold 

Jackpot less than 1 km northeast of the Texas Canyon project. 

Here, 1988–1990 drill-hole data and geochemical samples 

are reported to show structurally controlled near-surface 

anomalous gold and elevated silver, arsenic, and tellurium 

values (Mexivada Mining Corp., 2012, 2013). 

Tract INPR14, Scraper Springs—There is moderate (M) 

potential, with certainty level C, for high-fluorine, porphyrymolybdenum-associated gold-bearing polymetallic skarn 

and quartz-alunite epithermal gold-silver deposits in the 

Scraper Springs area, 15 km northeast of Midas, Elko County, 

Nevada (LaPointe and others, 1991; fig. 31O; appendix 2). 

The geology of the area is characterized by an exposure 

of Paleozoic rocks in a window of Eocene and Miocene 

volcanic rocks. Paleozoic and Eocene volcanic rocks have 

been intruded by 39 Ma porphyritic diorite and quartz syenite 

intrusions. Skarn developed in Paleozoic rocks around the 

intrusion, and Tertiary volcanic rocks have been silicified 

and pervasively argillized (Coats, 1987; LaPointe and others, 

1991; Crafford, 2007; Cantor, 2012)

The tract was delineated by aggregating 3-km buffers 

around a several-square-kilometer area of hydrothermally altered 

volcanic rocks and drill holes (Cantor, 2012). The tract encloses 

the Scraper Springs property, the Rebel Claims prospect, and a 

zunyite locality. Soil and stream-sediment geochemistry in the 

tract is characterized by high concentrations (more than 16 times 

background) of bismuth, moderately high to high concentrations 

(8 to 15 times background) of molybdenum, and moderately high 

concentrations (4 to 7 times background) of cadmium. Local, 

elevated concentrations of gold, selenium, and tin occur in stream 

sediments (U.S. Geological Survey, 2016b). The tract is cospatial 

with a modest magnetic high and near a northwest-trending 

moderate gravity high (Day and others, 2016). A northwesttrending zone of elevated potassium concentrations, as reflected 

by radiometric measurements, coincides with much of the tract 

(Day and others, 2016). Well-developed advanced argillic, ferric 

iron, and argillic alteration in the tract are interpreted from ASTER 

satellite imagery (Rockwell and others, 2015).

Previous assessments estimate that all or parts of this 

tract are permissive for polymetallic replacement, skarn, and 

porphyry copper deposits (U.S. Geological Survey, 2001), 
166 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

hot spring gold-silver deposits, quartz-adularia vein deposits, 

quartz-alunite gold deposits, and epithermal deposits of 

mercury, antimony, manganese, and tin (U.S. Geological 

Survey, 2001; Wallace and others, 2004; Parks and others, 

2016). There are 75 active lode claims in the tract (Dicken and 

San Juan, 2016).

Mineral occurrences in the district include the zunyite 

locality, the Rebel and Willow epithermal silver-bariummanganese prospects, and the Scraper Springs molybdenum-

(fluorine) exploration project. The zunyite locality was 

identified and studied in the late 1970s (Coats and others, 

1979). This occurrence generated exploration interest for 

quartz-alunite epithermal gold-silver deposits in the area. 

In the 1980s and 1990s, exploration efforts resulted in the 

identification of the porphyry molybdenum-(fluorine) and 

associated gold-bearing polymetallic skarn target at Scraper 

Springs (Cantor, 2012). At Scraper Springs, alteration minerals 

in breccias and stockwork veins in Eocene volcanic rocks 

and intrusions include K-feldspar, sericite, and quartz, and 

advanced argillic associations (quartz, alunite, pyrophyllite, 

pyrite, topaz, kaolinite, and zunyite; Coats and others, 1979). 

Skarn minerals occur in Paleozoic sedimentary rocks adjacent 

to intrusions. Based on drill-hole logs and cuttings analyses, 

altered rocks contain 3 to more than 8 percent pyrite and 

elevated concentrations of gold, silver, molybdenum, fluorine, 

copper, zinc, and lead, and lesser bismuth, tellurium, selenium, 

and tin (Cantor, 2012). Notwithstanding some encouraging drill 

intercepts, a resource estimate has not been published. Exposed 

mineralization at nearby prospects is characterized by small 

silver-barite-manganese quartz veins and breccia zones (Rebel 

claims), and fault-controlled jasperoid (Willow claims) in 

altered volcanic rocks (LaPointe and others, 1991).

Tract INPR15_pmr, Ashbrook Polymetallic Replacement—

There is moderate potential (M), with certainty level C, for 

porphyry-related Ag-Au-Pb-(Cu-Zn) polymetallic replacement 

deposits in the Ashbrook district of northwestern Box Elder 

County, 13 km northwest of Lynn, Utah (fig. 31P; appendix 2). 

The geology of the area is characterized by folded and faulted 

Proterozoic metasedimentary and Paleozoic sedimentary rocks 

that are intruded by ~13 Ma granite and rhyolite porphyry plugs, 

dikes, and sills that are possibly related to the Jarbidge volcanic 

suite. Eocene to early Miocene east-dipping faults resulted in 

top-to-west block rotation followed by Miocene to Pliocene faults 

associated with denudation of the Raft River-Grouse Creek-Albion 

metamorphic core complex adjacent to the east. Quaternary 

alluvium covers parts of the district (Compton and others, 1977; 

Hintze and others, 2000; Gloyn and Krahulec, 2006).

The Ashbrook district was staked in 1873, and through 1920 

had intermittent production. Mining was most active between 

1920 and 1923, and halted because of a drop in silver prices. 

Mining in the district revived between 1934 and 1941, but was 

closed by the federal precious metal mine closure act of 1941. Past 

production in the district is estimated at 180,000 short tons of ore 

which yielded 3,440,000 oz of silver. In the 1950s, an exploration 

drilling program was conducted by the U.S. Bureau of Mines, 

and the Vipont tailings were re-processed between 1978 and 1984 

(Gloyn and Krahulec, 2006).

The tract was delineated by aggregating 3-km buffers around 

projects, mines, and prospects. Moderate to strong 

(8 to 15 times and more than 16 times background) selenium and 

tin, and moderate (4 to 7 times background) silver geochemical 

anomalies occur in the tract (U.S. Geological Survey, 2016b). 

The district is located approximately 8 km north of a reduced-topole magnetic high that images the Grouse Creek Pluton, and a 

moderate-intensity, north-south Bouguer gravity ridge (Day and 

others, 2016). The radiometric thorium/potassium (Th/K) map 

shows that the district is located on a north-northwest-trending 

low. A northwest-trending zone indicating advanced argillic plus 

ferric iron, argillic, and lesser sericite alteration is interpreted from 

ASTER satellite imagery (Rockwell and others, 2015).

Previous assessments estimate that this area is permissive 

for quartz-adularia and quartz-alunite, and hot spring epithermal, 

and polymetallic replacement, porphyry, and skarn deposits (U.S. 

Geological Survey, 2001; Parks and others, 2016). There are 9 

active lode claims in the tract (Dicken and San Juan, 2016).

The Ashbrook district includes the Vipont, LexintonArgenta, Sentinell, and Skoro Ag-Au-Pb-(Cu-Zn) carbonate 

replacement deposits and other prospects. Replacement gangue 

and ore minerals were deposited from oldest to youngest in 

three stages: (1) rhodochrosite; (2) quartz, pyrite, arsenopyrite, 

sphalerite, and chalcopyrite; and (3) galena, argyrodite, 

pyrargyrite, pearceite, tennantite, and other silver sulfosalts. 

Oxidized and enriched ore includes argentite, covellite, 

chalcocite, cerussite, and native silver (Peterson, 1942; Doelling 

and others, 1980; Gloyn and Krahulec, 2006).

Tract INPR15_dd, Ashbrook Distal Disseminated SilverGold—There is high (H) potential, with certainty level D, for 

intrusion-related distal disseminated silver-gold deposits in the 

Ashbrook district of northwestern Box Elder County, 13 km 

northwest of Lynn, Utah (fig. 31P; appendix 2). The geology, 

regional geochemical, geophysical, and remote-sensing data 

that characterize the tract are described in report section “Tract 

INPR15_pmr, Ashbrook Polymetallic Replacement.”

A distal disseminated gold-silver deposit in the Ashbrook 

district is exposed at the Vipont Mine. Stratiform disseminated 

mineralization is associated with silver-rich polymetallic veins 

and replacements. The mineralogy and sequence of deposition 

of gangue and ore is the same as that reported for replacement 

deposits in the district. The Vipont Ag-Au deposit is reported to 

contain an open-pit-mineable mineral resource of approximately 

430,000 short tons at an average grade of 5.06 opt silver and 

0.01 opt gold (Peterson, 1942; Doelling and others, 1980; Gloyn 

and Krahulec, 2006).

Tract INPR15_pmv, Ashbrook Polymetallic Vein—There 

is moderate (M) potential, with certainty level C, for intrusionrelated Ag-Au-(Pb-Cu-Zn) polymetallic vein deposits in the 

Ashbrook district of northwestern Box Elder County, 13 km 

northwest of Lynn, Utah (fig. 31P; appendix 2). The geology 

of the area is described in report section “Tract INPR15_pmr, 

Ashbrook Polymetallic Replacement.”
Mineral-Resource Potential 167

Au-Ag-(Pb-Cu-Zn) polymetallic veins in the Ashbrook 

district include the Peg Leg, Dolly Clark, and Midway 

tunnel Mines. These veins exhibit ore mineral associations 

that are similar to those in related replacement deposits (see 

report section “Tract INPR15_pmr, Ashbrook Polymetallic 

Replacement”). These veins have been classified as 

epithermal (U.S. Geological Survey, 2016a; Fernette and 

others, 2016a).

Rock Units Favorable for Intrusion-Related 

Deposits

There is low potential (L), with certainty level B for 

intrusion-related mineral deposits in large areas within the 

four study areas. A tract that encloses these areas consists of 

numerous separate enclosures in each study area (tract INPR01, 

Pluton-related Permissive, Jurassic to Holocene intrusionrelated deposits; fig. 31Q; appendix 2). The boundaries of 

the tract are based on the Oregon, Idaho, Nevada, and Utah 

state geologic maps (fig. 3A; Walker and MacLeod, 1991; 

Hintze and others, 2000; Miller and others, 2002; Crafford, 

2007; Lewis and others, 2012). The boundaries enclose 

autochthonous and allochthonous Paleozoic and Mesozoic 

stratigraphy that has been superpositioned by crustal 

compression in the Paleozoic and Mesozoic, and Eocene 

to Holocene volcanic rocks and intrusions that have been 

distended by crustal extension during the late Tertiary (see 

report section “Introduction; Description of Geology”). 

Appropriate units were selected from digital geologic maps 

of Nevada, Oregon, Idaho, and Utah; permissive intrusive map 

units were buffered by 10 km, permissive volcanic map units 

were buffered by 2 km, and those buffered units were merged 

into tracts. Mineral-resource occurrences (U.S. Geological 

Survey, 2005) that correspond to intrusion-related deposits in 

permissive igneous rock map units were buffered by 10 km and 

those buffered units were merged into the permissive map unitbased tracts. The composited tracts were aggregated, using a 

5-km aggregation distance, and a 2,000-km2

 minimum hole size. 

The aggregated tracts were smoothed, using a 5-km tolerance. 

Areas within the aggregated tracts where the depth to basement 

rocks is interpreted to exceed 1 km (Day and others, 2016) were 

excluded. The resulting tracts enclose stratigraphy favorable for 

intrusion-related deposits similar to deposits within assessed 

tracts described above, and include several assessed tracts.

Early-stage exploration projects for which there is 

limited information and for which no work has been reported 

in the past 5 to 10 years are included in tract INPR01, 

Pluton-related Permissive. One area was identified in PLSS 

ID080080S0010W0 and PLSS ID080080S0010E0. The 

identified area includes the Silver Rock and Clover Mountain 

gold-silver-(base metal) vein systems (Fernette and others, 

2016a). These veins are associated with Oligocene rhyolite 

dikes hosted in Cretaceous granite. A soil geochemical 

survey was conducted in 2008 at the Clover Mountain active 

exploration project, but the results of this survey have not been 

published (Thunder Mountain Gold, 2013, 2016). The Silver 

Rock Mine had historic production; however, no lode claims are 

currently active (Bennett and others, 2010).

Buffering Intrusion-Related Tracts

The intrusion-related tracts described previously 

represent numerous deposit types, including polymetallic vein, 

skarn, replacement gold-silver-copper-lead-zinc deposits, 

porphyry copper deposits, porphyry molybdenum deposits, 

tungsten greisen deposits, and distal disseminated goldsilver deposits. All intrusion-related tracts were delineated 

from characteristics of deposit models for these deposit 

types, which were assembled from characteristics of welldocumented intrusion-related deposits and the magmatichydrothermal systems that formed the deposits (Day and 

others, 2016; appendix 2). Some of these characteristics may 

be concealed (for example, altered rocks covered by younger 

rocks; drill-defined polymetallic resources; deposits identified 

by drill-hole intercepts with elevated metal values) whereas 

others are detectable only by instrumentation (for example, 

gravimetric, magnetic, and radiometric surveys) and do not 

appear on published maps (geologic; topographic) or may not 

appear in other publications.

Metal occurrences and intrusions on published maps and in 

other publications were the initial criteria used to delineate tracts 

for possible concealed and unmapped intrusion-related deposits. 

Other criteria used included the alteration, geochemical, and 

geophysical signatures of the magmatic-hydrothermal systems 

that form intrusion-related deposits. The approximate diameters 

of “footprints” (surface exposures) of well-exposed intrusionrelated systems range from hundreds of meters to tens of 

kilometers for very large to “giant” systems (Sillitoe, 2010; 

Richards, 2013). Since no evidence for very large to giant 

intrusion-related systems has been found in the study area for 

the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

radii less than 10 km from intrusion-related metal occurrences 

broadly represent the uncertainty associated with the location 

of an intrusion-related occurrence within concealed to partly 

concealed, small to large, intrusion-related systems (those with 

diameters of hundreds of meters to about 10 km). Additional 

footprint refinement of intrusion-related systems was derived 

from the median and 90th-percentile radii, about 0.6 km and 

2.6 km, respectively, of porphyry copper systems (Singer and 

others, 2008). These radii are minima because many porphyry 

systems used in their calculation are partly covered. For 

tract delineation in the study area for the Southern Idaho and 

Northern Nevada Sagebrush Focal Area, a 3-km buffer radius 

centered on intrusion-related metal occurrences was selected to 

represent the uncertainty associated with the surface projection 

of concealed to partly concealed intrusion-related systems. Tract 

boundaries represent the merged circumferences of circles (with 

3-km radii) concentric to all intrusion-related metal occurrences 

within the tract.
168 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Mineral Potential Tracts for Volcanogenic 

Massive Sulfide Copper Deposits

One low potential tract and two nested high potential 

tracts with different certainty levels were delineated for VMS 

deposits: tract INMS01, VMS Permissive; tract INMS02, Rio 

Tinto 1; and INMS03, Rio Tinto 2.

Tract INMS01, VMS Permissive—There is low potential 

(L), with certainty level B, for VMS copper-zinc-leadsilver-gold deposits in the study area (tract INMS01, VMS 

Permissive; fig. 31R; appendix 2). In VMS systems, sulfide 

minerals precipitate near seafloor vents where circulating 

hydrothermal fluids driven by magmatic heat mix with cool 

seawater (Shanks and Thurston, 2010). In Nevada, submarine 

volcanic rocks and VMS deposits and occurrences (Sherlock 

and others, 1996) occur in the following geologic map units: 

Black Rock/Pueblo terrane (unit Mzbr), Golconda allochthon 

(unit Pzh), and Roberts Mountains allochthon (unit Pzrm) 

(fig. 27). The tract encloses these units plus a 1-km buffer to 

account for cover and uncertainty of mapped contacts.

Tract INMS02, Rio Tinto 1; Tract INMS03, Rio Tinto 

2—There is high potential (H), with certainty levels D (Rio 

Tinto 1) and C (Rio Tinto 2), for volcanogenic massive 

sulfide copper-zinc-lead-silver-gold deposits (VMS) in 

an area centered on the Rio Tinto Mine, which is largely 

within the proposed withdrawal area within the study area 

(tract INMS02, Rio Tinto 1; tract INMS03, Rio Tinto 2; 

fig. 31R; appendix 2; Coats and Stephens, 1968; LaPointe 

and others, 1991). From 1932 to 1949, this mine produced 

1,110,000 million short tons of ore from the Ordovician 

Valmy Formation with an average grade of 9.7 percent 

copper (Coats and Stephens, 1968; LaPointe and others, 

1991). Because VMS deposits are known to occur in 

clusters (Shanks and Thurston, 2010), two buffers, 1.8 km 

and 6.7 km in width, were applied to the Rio Tinto Mine, 

which correspond to the 50th- and 90th-percentile spacing 

between VMS deposits in five well-described VMS districts 

(Galley and others, 2007). Deposit buffers were trimmed 

to map units of the Roberts Mountains allochthon and 

a 1-km-wide buffer was added to account for cover and 

uncertain contacts. There is high potential with certainty 

level D within the 1.8-km-wide buffer (dark magenta) and 

high potential with certainty level C within the 6.7-km-wide 

buffer (light magenta; fig. 31R). Within the tract, anomalous 

concentrations of copper, silver, gold, and arsenic are present 

in stream sediments (Day and others, 2016; Smith and others, 

2016). Supergene weathering and oxidation of associated 

pyrite in enclosing rocks (Coats and Stephens, 1968; 

LaPointe and others, 1991) are evident in the distribution 

of ferric and ferrous iron, and argillic alteration, based on 

interpretation of Landsat and ASTER imagery (Rockwell and 

others, 2015). The tract includes numerous patented, active, 

and historic lode claims (fig. 29; tables 16, 17; Causey, 

2007, 2011) but no exploration activity (Fernette and others, 

2016a).

Mineral Potential Tracts for Carlin-Type Gold 

Deposits

One low potential tract, four moderate potential tracts, 

and four nested high potential tracts were delineated for 

Carlin-type gold deposits: tract INCT01, Carlin Permissive; 

tract INCT02, Willow 1; tract INCT03, Willow 2; tract 

INCT04, Big Springs 1; tract INCT05, Big Springs 2; tract 

INCT06, Doby George 1; tract INCT07, Doby George 2; tract 

INCT08, North Star 1; and tract INCT09, North Star 2.

Tract INCT01, Carlin Permissive—There is low potential 

(L), with certainty level B, for Carlin-type gold deposits over 

much of the eastern part the study area for the Southern Idaho 

and Northern Nevada Sagebrush Focal Area (tract INCT01, 

Carlin Permissive; fig. 31S; appendix 2). In Eocene Carlintype systems, gold-bearing disseminated pyrite precipitates 

where hydrogen sulfide-bearing hydrothermal fluids react 

with iron-bearing minerals or fluids in sedimentary rocks 

(Hofstra and Cline, 2000). In areas of Nevada adjacent to 

the tract, most production and resources of Carlin-type gold 

deposits occur in Paleozoic sedimentary rocks deposited near 

the platform margin in slope environments, although gold 

deposits also are present in marginal basin, shelf, foreland 

basin, and overlap sequences (Cline and others, 2005; Berger 

and others, 2014; Cook, 2015). These sedimentary rocks 

correspond to the following geologic map units: sedimentary 

rock units of the North American Continental Shelf, Roberts 

Mountains allochthon, and Golconda allochthon (fig. 27). The 

low potential tract includes these units and a 1-km buffer to 

account for cover and uncertainty of contacts.

Tract INCT02, Willow 1; Tract INCT03, Willow 2—There 

is moderate potential (M), with certainty levels D (Willow 

1) and C (Willow 2), for Carlin-type gold deposits in an area 

centered on the Willow active exploration project (Carlin Gold 

Company, 2016; Fernette and others, 2016a), which extends 

into the proposed withdrawal area (tract INCT02, Willow 1; 

tract INCT03, Willow 2; fig. 31S; appendix 2). 

Because Carlin-type gold deposits occur in clusters 

(Hofstra and Cline, 2000), two buffers, 4.2 km and 2.0 km in 

width, were applied to the active exploration area and three 

prospects (Fernette and others, 2016a), which correspond to 

the 50th- and 90th-percentile spacing, respectively, between 

Carlin-type gold deposits in Nevada (Berger and others, 

2014). The west side of the resulting tract was trimmed 

to stratigraphy favorable for Carlin-type gold deposits 

(sedimentary rock units of the North American Continental 

Shelf, Roberts Mountains allochthon, and Golconda 

allochthon; fig. 27). The tract boundary was extended to the 

southeast to include an area with moderately anomalous gold 

in stream sediments (Day and others, 2016; Smith and others, 

2016). There is moderate potential with certainty level D 

within the 2.0-km-wide buffer and moderate potential with 

certainty level C in the rest of the tract (fig. 31S). 

The geology of the tract is typical of Carlin-type gold districts 

in Nevada (Carlin Gold Company, 2016). Alteration, including 
Mineral-Resource Potential 169

silicification (jasperoid), decalcification, and argillization, and 

gold, occur along northeast-striking, high-angle faults in the 

Ordovician and Silurian Hanson Creek Formation and Silurian 

and Devonian Roberts Mountains Formation. An Eocene felsic 

dike is phyllically altered. These formations are exposed between 

a northwest-striking range front fault and the Roberts Mountains 

thrust fault. Drilling of the Hot Creek prospect in the 1980s was 

based on gold, arsenic, and mercury anomalies near jasperoid 

(LaPointe and others, 1991); two additional holes were drilled 

in 2008 (Carlin Gold Company, 2016). Rock samples contain 

as much as 368 ppb gold at Currant Creek, as much as 159 ppb 

gold at Badger Creek, and anomalous concentrations of arsenic, 

antimony, mercury, and thallium (Carlin Gold Company, 2016).

The tract encloses several PLSS sections with plans of 

operations and notices for gold as well as numerous active, 

closed, and historic lode claims (figs. 28, 29; tables 16, 17, 18, 

19; Causey, 2007, 2011). 

Tract INCT04, Big Springs 1; Tract INCT05, Big 

Springs 2—There is high potential (H), with certainty levels 

D (Big Springs 1) and C (Big Springs 2), for Carlin-type 

gold deposits in an area centered on the Big Springs Mine, 

which is outside the proposed withdrawal area but is adjacent to 

the Nevada additions study area (tract INCT04, Big Springs 1; 

tract INCT05, Big Springs 2; fig. 31S; appendix 2). From 1987 

to 1993, the Big Springs Mine produced 386,000 oz of gold at 

0.12 opt gold. The mine is within an active exploration area that 

includes seven discrete deposits with an inferred total resource 

defined by 2,400 drill holes of 14.8 million metric tons at 2 g/t 

gold (table 20; 16.3 million short tons at 0.06 opt gold; Anova 

Metals Limited, 2016; fig. 30). 

Because Carlin-type gold deposits occur in clusters 

(Hofstra and Cline, 2000), two buffers, 4.2 km and 2.0 km in 

width, were applied to deposits, resources, and prospects in 

the mining district (U.S. Geological Survey 2005; Western 

Exploration and Development Ltd., 2008; Anova Metals Ltd., 

2016; Fernette and others, 2016a), which correspond to the 

50th- and 90th-percentile spacing between Carlin-type gold 

deposits in Nevada (Berger and others, 2014). The southwest 

side of the buffer was trimmed to the study area boundary, 

and the southeast side was trimmed to stratigraphy favorable 

for Carlin-type gold deposits (sedimentary rock units of 

the North American Continental Shelf, Roberts Mountains 

allochthon, and Golconda allochthon; fig. 27). There is high 

potential with certainty level D within the 2.0-km-wide 

buffer and high potential with certainty level C within the 

4.2-km-wide buffer (fig. 31S).

In this tract, gold deposits and resources mainly occur along 

high-angle faults in the Devonian to Pennsylvanian Dorsey 

Creek and Mikes Creek Members of the Schoonover Formation 

(Adams, 1996), which is part of the Golconda allochthon (fig.27).

Alteration, mineralization, and geochemical values in nearby 

prospects in the Schoonover Formation, in the Ordovician 

Valmy Formation of the Roberts Mountains allochthon, and 

in underlying Ordovician to Devonian carbonate rocks, are 

consistent with Carlin-type gold deposits. These rocks are partially 

covered by Tertiary volcanic rocks and Quaternary alluvium. 

Gold is associated with carbonate dissolution and silicification 

(Youngerman, 1992; Adams, 1996). The deposits contain in 

addition to gold, anomalous concentrations of arsenic, antimony, 

mercury, thallium, and cadmium (Youngerman, 1992). Ferric 

and ferrous iron occurs in the vicinity of deposits, based on 

interpretation of Landsat imagery (Rockwell and others, 2015). 

The tract includes one section with a closed plan of operations for 

gold as well as numerous active closed and historic lode claims 

(figs. 28, 29; tables 16, 17, 18, 19; Causey, 2007, 2011).

Tract INCT06, Doby George 1; Tract INCT07, Doby George 

2—There is high potential (H), with certainty levels D (Doby 

George 1) and C (Doby George 2), for Carlin-type gold deposits in 

an area centered on the Doby George deposit (Western Exploration 

and Development, Ltd., 2008; Fernette and others, 2016a), which 

extends into the proposed withdrawal area (tract INCT06, Doby 

George 1; tract INCT07, Doby George 2; fig. 31S; appendix 2; 

Western Exploration and Development Ltd., 2008). The Doby 

George deposit, which is part of an active exploration area (map 

and cross section in LaPointe and others, 1991), has a NI 43-101 

compliant gold resource, defined by 577 drill holes, of 27.1 million 

short tons at 0.028 opt gold (table 20; Western Exploration and 

Development Ltd., 2008).

Because Carlin-type gold deposits occur in clusters (Hofstra 

and Cline, 2000), two buffers, 4.2 km and 2.0 km in width, were 

applied to the gold resource and a nearby gold prospect (Western 

Exploration and Development Ltd., 2008; Fernette and others, 

2016a), which correspond to the 50th- and 90th-percentile spacing 

between Carlin-type gold deposits in Nevada (Berger and others, 

2014). The buffers were trimmed to stratigraphy favorable for 

Carlin-type gold deposits (sedimentary rock units of the North 

American Continental Shelf, Roberts Mountains allochthon, 

and Golconda allochthon; fig. 27). There is high potential with 

certainty level D within the 2.0-km-wide buffer and high potential 

with certainty level C within the 4.2-km-wide buffer (fig. 31S).

Based on the Western Exploration and Development 

Ltd. (2008) report, gold-mineralized rocks are localized along 

northeast- and northwest-striking, high-angle faults in calcareous 

siltstones and sandstones of the Schoonover sequence, which is 

part of the Golconda allochthon (fig. 27). Other potential host 

rocks include hornfels and skarn adjacent to a Cretaceous stock, 

and the Pennsylvanian Van Duzer Limestone, which occurs at 

a depth of about 1,500 ft in the deposit area. Gold resources are 

associated with silicified fault zones, decalcification, argillic 

alteration, and, in deep drill holes, carbon remobilization. 

Supergene oxidation extends about 400 ft below the surface. 

Sericitic alteration occurs with high-grade gold- mineralized rock 

along fractures in Mesozoic granodiorite. Drill intercepts contain 

as much as 0.719 opt gold. Soils are anomalous in gold, arsenic, 

and antimony. Stream sediments are anomalous in arsenic (Day 

and others, 2016; Smith and others, 2016). Ferric iron and clay 

minerals, and minor phyllic alteration, occur in the vicinity of 

deposits, based on interpretation of Landsat and ASTER imagery 

(Rockwell and others, 2015).

The tract includes two sections with closed notices for 

gold as well as numerous active, closed, and historic lode 

claims (figs. 28, 29; tables 16, 17, 18, 19; Causey, 2007, 2011).
170 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Tract INCT08, North Star 1; Tract INCT09, North 

Star 2—There is moderate potential (M), with certainty 

level D (North Star 1) and C (North Star 2), for Carlin-type 

gold deposits in an area centered on the North Star active 

exploration area, which covers a small proposed withdrawal 

area (tract INCT08, North Star 1; tract INCT09, North Star2; 

fig. 31S; appendix 2; Altan Nevada Minerals Ltd., 2015; 

Fernette and others, 2016a).

Because Carlin-type gold deposits occur in clusters 

(Hofstra and Cline, 2000), two buffers, 4.2 km and 2.0 km in 

width, were applied to the exploration area, which correspond 

to the 50th- and 90th-percentile spacing between Carlintype gold deposits in Nevada (Berger and others, 2014). The 

buffers were trimmed to stratigraphy favorable for Carlintype gold deposits (sedimentary rock units of the North 

American Continental Shelf, Roberts Mountains allochthon, 

and Golconda allochthon; fig. 27). There is moderate 

potential with certainty level D within the 2.0-km-wide buffer 

and moderate potential with certainty level C within the 

4.2-km-wide buffer (fig. 31S). 

Based on the Altan Nevada Minerals Ltd. (2015) report, 

jasperoid along a north-northeast-striking, high-angle fault 

in the Ordovician Vinini Formation contains as much as 

1.059 ppm gold, 457 ppm arsenic, 14 ppm antimony, and 

3.6 ppm mercury, and is enveloped by a 2-km-long gold, 

arsenic, and antimony soil anomaly. A drill hole encountered 

decalcification and silicification in the Vinini Formation and 

anomalous mercury in strata that resemble the Devonian 

Rodeo Creek unit, which is an important host rock for Carlintype gold deposits (Cline and others, 2005). Ferric and ferrous 

iron minerals, phyllic alteration, and hydrous silica occur in 

the vicinity of deposits, based on interpretation of Landsat and 

ASTER imagery (Rockwell and others, 2015). 

There were 163 lode claims in the exploration area in 

2015 (Altan Nevada Minerals Ltd., 2015). The tract includes 

two sections with active and numerous closed notices for gold, 

as well as numerous active, closed, and historic lode claims 

(figs. 28, 29; tables 16, 17, 18, 19; Causey, 2007, 2011). 

Stratigraphy Favorable for Black Shale 

Vanadium Deposits

There is low potential (L), with certainty level B, for 

vanadium deposits in Paleozoic, organic-rich, black shales 

in the study area. Vanadium in seawater is concentrated in 

organic matter that accumulates in euxinic basins with high 

organic productivity and low clastic sedimentation rates 

(Breit and Wanty, 1991; Lehmann and others, 2007). The 

resulting organic-rich black shales are petroleum source rocks 

(Poole and Claypoole, 1984; Anna and others, 2007) and 

typically contain anomalous concentrations of metals and 

trace elements (Desborough and Poole, 1983; Lehmann and 

others, 2007). In some basins, they occur with phosphorite 

(McKelvey and others, 1986), bedded barite (Papke, 1984), 

or SEDEX zinc-lead-silver-gold deposits (Emsbo, 2000, 

2009). Some of these black shales have been proposed to be 

potential sources for gold and minor elements in Carlin-type 

gold deposits (Emsbo and others, 2003; Large and others, 

2011). In neighboring areas of Nevada and Idaho, black shales 

with potentially extractable concentrations of vanadium (more 

than or equal to 1,500 ppm vanadium; American Vanadium, 

2011) are present in the following stratigraphic units: Permian 

Phosphoria Formation, Mississippian Chainman Shale, 

Devonian and Mississippian Pilot Shale, Devonian Popovich 

Formation, Devonian Woodruff Formation, Ordovician Vinini 

Formation, and correlative formations (Desborough and Poole, 

1983; Maughan, 1984; McKelvey and others, 1986; Poole and 

others, 1992; Emsbo and others, 2003; Hofstra and others, 

2011; American Vanadium, 2011; Poole and Sandberg, 2015; 

American Vanadium, 2015; National Geochemical Database, 

U.S. Geological Survey, 2016b; Stina Resources Ltd., 2016). 

Although black shale vanadium resources may be present in 

these formations in the study area, there is little or no evidence 

of exploration, detailed mapping, or analyses for vanadium. 

Consequently, no permissive tracts were delineated and no 

tracts with moderate or high potential were identified.

Stratigraphy Favorable for Sedimentary 

Exhalative (SEDEX) Zinc-Lead-Silver-Gold 

Deposits

There is low potential (L), with certainty level B, for 

SEDEX zinc-lead-silver-gold deposits in Ordovician and 

Devonian, organic-rich, black shales in the study area. In 

SEDEX systems, ore minerals precipitate in organic-rich, 

black shales when metal-laden basinal brines vent into euxinic 

seawater in bathymetric lows (Emsbo, 2009). In areas of 

Nevada adjacent to the study area, SEDEX deposits with 

potentially extractable concentrations of metals occur in the 

following stratigraphic units: Devonian Popovich Formation 

(Upper Zone of the Rodeo deposit; Emsbo, 2000), Devonian 

Rodeo Creek unit (Mike deposit; Bawden and others, 2003), 

Ordovician Vinini Formation (Blue Basin prospect and LAJ 

claims; LaPointe and others, 1991), and perhaps in other 

formations. Although SEDEX zinc-lead-silver-gold resources 

may be present in the study area, there is little or no evidence 

of exploration for, or descriptions of, SEDEX occurrences. 

Consequently, no tracts were delineated and no tracts with 

moderate or high potential were identified.

Stratigraphy Favorable for Mississippi ValleyType (MVT) Lead and Zinc Deposits

There is low potential (L), with certainty level B, 

for MVT lead and zinc deposits in the study area. In MVT 

systems, ore minerals precipitate in sedimentary rocks 

deposited in shelf sequences where metal-laden basinal brines 

mix with contrasting aqueous fluids, or natural gas, containing 

hydrogen sulfide (Leach and others, 2010). Geologic map 
Mineral-Resource Potential 171

unit PzMzs (sedimentary rock units of the North American 

Continental Shelf; fig. 27) is a permissive host unit for MVT 

deposits. In areas of Nevada adjacent to the study area, 

dolomitized limestones and hydrothermal dolomite represent 

brine migration pathways; MVT deposits and occurrences 

with potentially extractable concentrations of zinc, lead, 

silver, and barite have been identified at several locations 

(Papke, 1984; LaPointe and others, 1991; Diehl and others, 

2005, 2010), including Black Mountain which is an active 

exploration project (Firestone Ventures, 2016). Although MVT

lead and zinc deposits may be present in the study area, there 

is little or no evidence of exploration for, or descriptions of, 

MVT deposits or occurrences. Consequently, no permissive 

tracts were drawn.

Market Analyses of Gold, Silver, Uranium, 

Copper, Molybdenum, Lead, Zinc, and Tungsten

Market analyses of gold, silver, uranium, copper, 

molybdenum, lead, zinc, and tungsten is provided in appendix 5 

and section I of Day and others (2016).

Mineral Potential Tracts for Lacustrine 

Diatomite Deposits

Four tracts were delineated and rated for lacustrine 

diatomite deposits: tract INDT01, Dickshooter; tract INDT02, 

Dickshooter North; tract INDT03, Owyhee-Twin Falls; and 

tract INDT04, Owyhee-Twin Falls-Cassia-Elko. 

Tract INDT01, Dickshooter—High potential (H), at 

certainty level D, for lacustrine diatomite deposits is assigned 

to an area in western Owyhee County, Idaho (tract INDT01, 

Dickshooter; fig. 31T; appendix 2). The Dickshooter tract 

is based on (1) two sites of past diatomite production (U.S. 

Geological Survey, 2016a); (2) an active plan of operations, 

apparently for diatomite (table 19) in sec. 27, T. 11 S., R. 2 W. 

and sec. 3, T. 12 S., R. 2 W.; (3) active millsites in sec. 2, T. 

12 S., R. 2 W. and sec. 34, T. 11 S., R. 2 W., and active placer 

claims in sec. 3, T. 12 S., R. 2 W. (tables 16, 17); and (4) a 

published account of the diatomite deposit describing historic 

claims in sec. 34 and 35, south half of sec. 36, T. 11 S., R. 2 

W., and all of sec. 2 and 3, T. 12 S., R. 2 W. (Powers, 1947); 

and (5) the Owyhee County geologic map (1:125,000 scale) 

unit Tbs sediments that locally contain diatomite interbedded 

within the Miocene Banbury Basalt of the Idaho Group (Ekren 

and others, 1981).

On the Idaho state map (1:500,000 scale), the generalized 

host lithologic unit for Dickshooter tract is depicted as 

the broadly extensive unit Tpb that consists of Pliocene 

basalt flows, pyroclastic debris, clastic sediments, and 

diatomite (Bond and others, 1978). According to Malde and 

Powers (1962), this unit might include Miocene, Pliocene, 

or Pleistocene “Lake Idaho” sediments—units that are 

semiequivalent to Succor Creek unit, Banbury Basalt, 

Bruneau, Chalk Hills, Glenns Ferry, and Poison Creek 

formations. The more specific host unit for the Dickshooter 

past producing mine is mapped on the Owyhee County 

geologic map (1:125,000 scale) as unit Tbs sediments that 

locally contain diatomite interbedded within the Miocene 

Banbury Basalt (Ekren and others, 1981). In Powers (1947), 

this diatomite exposure corresponds with a drainage that has 

eroded through the capping basalt.

No previous mineral-resource assessments have been 

conducted in the tract area. 

Tract INDT02, Dickshooter North—Moderate potential 

(M), at certainty level C, for lacustrine diatomite deposits 

is assigned to an area north-northeast of tract INDT01, 

Dickshooter, in Owyhee County, Idaho (tract INDT02, 

Dickshooter North; fig. 31T; appendix 2). No current or past 

production and no identified prospects or occurrences were 

recorded within the two sections that comprise the Dickshooter 

North tract (sec. 11, T. 11 S., R. 2 W. and sec. 19, T. 10 S., 

R. 1 W.). Tract delineation and rating are based on (1) BLMauthorized surface-management plans, apparently for diatomite; 

and (2) the location of the two sections being within the 

generalized lithologic unit on the Idaho state map (1:500,000 

scale) depicted as the broadly extensive unit Tpb Pliocene basalt 

flows, pyroclastic debris, clastic sediments, and diatomite (Bond 

and others, 1978), which corresponds with the unit Tb Miocene 

Banbury Basalt (Ekren and others, 1981).

Two previous mineral assessments were conducted at 

Pole Creek just to the west and inside the margin of the tract. 

In a report prepared for the BLM, Mathews and Blackburn 

(1983) determined that the Pole Creek area (Gem Resources 

Area ID-010-10), which includes T. 11 S., R. 2 W., has high 

favorability for diatomite resources with a confidence level 

equivalent to a certainty of the current rating of D; they further 

stated that the probability of diatomite deposits within the 

Tbs map unit (Banbury Basalt) is excellent. Subsequently, the 

mineral assessment of the Pole Creek Wilderness Study Area 

(U.S. Geological Survey and U.S. Bureau of Mines, 1989) 

recognized a high favorability for diatomite, but did not rate 

the mineral potential.

Tract INDT03, Owyhee-Twin Falls—Moderate potential 

(M) for lacustrine diatomite deposits, at certainty level B, 

is assigned to an area of Owyhee and Twin Falls Counties, 

Idaho (tract INDT03, Owyhee-Twin Falls; fig. 31T; appendix 

2). The tract is delineated on the basis of lithologic units (1) 

from the Owyhee County Geologic Map (1:125,000 scale) that 

include unit Tbs Miocene sediments with lacustrine diatomite 

interbeds within the Banbury Basalt and unit Tch Miocene and 

Pliocene Chalk Hills Formation lake and stream deposits with 

diatomite in the Idaho Group (Ekren and others, 1981); and (2) 

the Twin Falls Quadrangle Geologic Map (1:250,000 scale) 

that include unit Qbs Pleistocene sediments with lacustrine 

diatomite within the Bruneau Formation and unit Tbs Pliocene 

sediments with lacustrine diatomite within the Banbury 

Basalt (Rember and Bennett, 1979). The tract is partially 

equivalent to the Miocene to Pleistocene stratigraphic unit 

Tpd from the Idaho state map (1:500,000 scale) (Bond and 
172 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

others, 1978) that includes diatomite as a minor or incidental 

lithology among sedimentary units associated with volcanic 

strata. The more detailed maps of Rember and Bennett (1979) 

and Ekren and others (1981) used to delineate the tract were 

georeferenced from .pdf files and digitized to bring them into a 

geographic information system (GIS), which enabled a higher 

resolution of areas where diatomite is exposed at the surface 

and along stream drainages.

The diatomite potential from previous mineral 

assessments conducted in the tract area was low and of C 

and D certainty (U.S. Geological Survey and U.S. Bureau 

of Mines, 1989). The Pole Creek Wilderness Study Area has 

high potential for lacustrine diatomite, with the equivalent of 

a certainty level of D. No current production is recorded in 

the tract. The only past production or active claims, plans of 

operations, or notices in the tract area are those indicated for 

tract INDT01, Dickshooter, and the adjacent tract INDT02, 

Dickshooter North.

Tract INDT04, Owyhee-Twin Falls-Cassia-Elko—This 

tract is rated as low potential (L) for lacustrine diatomite 

deposits at certainty level B (fig. 31T). It is located in 

Owyhee, Twin Falls, and Cassia Counties of southwestern 

Idaho, and Elko County, Nevada. The tract is delineated on 

the basis of permissive geology from (1) Idaho state map 

(1:500,000 scale) unit Tpb Pliocene basalt flows, pyroclastic 

debris, clastic sediments, and diatomite, and the coeval unit 

Tpd-Tpv Pliocene sandstone, conglomerate, siltstone, tuff, 

claystone, limestone, and diatomite (Bond and others, 1978); 

and (2) Nevada state map (1:250,000) unit QTls Holocene to 

Pliocene landslide deposits, colluvium, and talus mixed with 

basalt, tuff, diatomite, and tuffaceous sediments (Crafford, 

2007).

Although this type of lithology extends across the state 

border into Nevada, no state-scale maps indicate diatomite 

among the lithologic units in Elko and Humboldt Counties 

(Stewart and Carlson, 1978; Crafford, 2007). As a result, 

a system of Miocene to Pleistocene lake beds in northern 

Nevada, represented as unit Ts3 (Crafford, 2007) and 

equivalent units Ts3 and Tts (Stewart and Carlson, 1978) 

that include the Humboldt and Carlin Formations, which are 

known to variably host diatomite or diatomaceous sediments 

(Wallace, 2003), are not included in this tract.

The diatomite potential from previous mineral 

assessments conducted in areas within the tract was low 

and ranged from B, C, to D certainty (U.S. Geological 

Survey and U.S. Bureau of Mines, 1989). The Pole Creek 

Wilderness Study Area has high potential with the equivalent 

of a certainty level of D. In a single location within the 

proposed withdrawal area, but adjacent to (outside) the tract 

boundaries, the Imperial Mercury Prospect contains diatomite 

associated with gold and mercury mineralization (U.S. 

Geological Survey, 2016a). No current or past production, 

active claims, plans of operations, or notices for diatomite 

in the tract area are on record other than those indicated for 

tract INDT01, Dickshooter, and the adjacent tract INDT02, 

Dickshooter North.

Mineral Potential Tracts for Bedded Barite 

Deposits

A low potential tract and two nested high potential tracts 

were delineated for bedded barite deposits: tract INBB01, Beddedbarite; tract INBB02, Snake Mountains 1; and tract INBB03, 

Snake Mountains 2.

Tract INBB01, Bedded-barite Permissive—There is low 

potential (L), with certainty level B, for bedded barite deposits in 

the study area (tract INBB01, Bedded-barite Permissive; fig. 

31U). In sedimentary basins, barite precipitates from reduced 

basinal fluids that vent into oxygenated seawater containing sulfate 

(Johnson and others, 2009). In areas of Nevada adjacent to the 

study area, the vast majority of barite production is from bedded 

deposits in the Devonian Slaven Chert and Ordovician Vinini, 

Valmy, or Comus Formations (Papke, 1984; Poole, 1988; Koski 

and Hein, 2003; Papke and Castor, 2003). These formations occur 

within the geologic map unit comprising the Roberts Mountains 

allochthon (unit Pzrm; fig. 27). The tract includes this unit and a 

1-km-wide buffer to account for cover and uncertainty of mapped 

contacts.

Tract INBB02, Snake Mountains 1; Tract INBB03, Snake 

Mountains 2—There is high potential (H), with certainty 

level D (Snake Mountains 1) and C (Snake Mountains 2), 

for bedded barite deposits in an area centered on the Snake 

Mountains, which extends into the proposed withdrawal area 

(tract INBB02, Snake Mountains 1; tract INBB03, Snake 

Mountains2; fig. 31U; appendix 2). The tract is based on 

stratigraphy (Ordovician Valmy Formation) that hosts 7 bedded 

barite mines and 17 prospects from which more than 1 million 

short tons of barite has been produced (table 20; Papke, 1984; 

LaPointe and others, 1991; Fernette and others, 2016a). The 

tract includes anomalous concentrations of barium in stream 

sediments (Day and others, 2016; Smith and others 2016). 

Supergene weathering and oxidation of associated pyrite in 

enclosing siliciclastic rocks (Papke, 1984) are evident in the 

distribution of ferric and ferrous iron based on interpretation of 

Landsat imagery (Rockwell and others, 2015). 

Because bedded barite deposits occur in clusters (Papke, 

1984), two buffers, 2.7 km and 1.3 km in width, were applied to 

the deposits and prospects, which correspond to the 75th- and 

90th-percentile spacing between bedded barite deposits in the 

Roberts Mountains allochthon in Nevada (Fernette and others, 

2016a). There is high potential (H) with certainty level D within 

the 1.3-km-wide buffer and high potential with certainty level C in 

the rest of the tract (figs. 31A–31U). 

The tract includes several PLSS sections with active and 

closed plans of operations and notices for barite as well as 

numerous active, closed, and historic lode claims (figs. 28, 29; 

tables 16, 17, 18, 19; Causey, 2007, 2011).

Market Analyses of Diatomite and Barite

Market analyses of diatomite and barite is provided in 

appendix 5 and section I of Day and others (2016).
Mineral-Resource Potential 173

Occurrence of Leasable Minerals

Leasable mineral commodities (leasable solid and fluid 

minerals) include oil and gas, geothermal, coal, and nonenergy solid minerals, including phosphate and potash. These 

commodities were not evaluated for assessment, but were 

qualitatively appraised for exploration and mining activity, lease 

status, and potential for deposits within the study area for the 

Southern Idaho and Northern Nevada Sagebrush Focal Area. 

No production of leasable solid minerals (coal, phosphate, and 

potash) or production of leasable fluid minerals (oil and gas, and 

geothermal) is recorded for this study area. Based on comparison 

to deposits of these commodities elsewhere in the western United 

States with past or present production (including oil and gas fields, 

and geothermal fields), and current market conditions, neither 

concealed or exposed deposits of these commodities are likely to 

be explored for, or produced, in coming decades.

The leasable solid and fluid mineral commodities coal, 

geothermal, oil and gas, and phosphate have been explored 

for or occur in the study area. Although there is no recorded 

production of these commodities, authorized, pending, and 

closed leases for oil and gas (1,029 leases) and geothermal 

(7 leases; table 16; figs. 32, 33) indicate that exploration for 

these commodities has occurred in recent years. Oil and gas 

exploration, leases, dry wells, and geothermal leases and 

sites, are described for all four study areas in report section 

“Introduction; Leasable Minerals.”

There are no records of coal and phosphate leases. 

However, two coal fields, phosphorite beds (containing 

elevated concentrations of phosphate), and favorable 

stratigraphy for coal and phosphate deposits, are exposed in 

the eastern part of the study area. Insufficient quantity and 

(or) unmarketable quality of the coal fields and phosphorite 

beds have precluded production. The coal fields and phosphate 

occurrences are described in the following paragraphs.

Coal

A coal resource is a naturally occurring concentration 

or deposit of coal in the Earth’s crust in such forms and 

amounts that economic extraction is currently or potentially 

feasible (Wood and others, 1983). Part of the study area for 

the Southern Idaho and Northern Nevada Sagebrush Focal 

Area is within the Goose Creek coal field (East, 2013) and 

Grouse Creek coal field (Tabet, 2010; fig. 34). Both coal fields 

contain lignite of Paleogene age (Tabet, 2010; East, 2013). 

No other coal fields or coal regions are within the 25-km 

buffer zone. The USGS drilled six reconnaissance holes in the 

Goose Creek coal field but did not conduct a coal resource 

assessment. There is no known mining of the lignite beds 

in the Goose Creek and Grouse Creek coal fields in Utah 

(Doelling, 1972). A report by the State of Utah (2004) makes a 

reference to nine small coal fields (including the Goose Creek 

and Grouse Creek coal fields) stating that they “contain very 

small amounts of coal and will not likely be mined in the next 

50 years.”

The Goose Creek and Grouse Creek coal fields are situated 

in narrow structural basins in the northeastern part of the Basin 

and Range Province. Coal in the fields occurs within gently 

folded and significantly faulted sedimentary and volcanic 

beds that comprise the Salt Lake Formation and Payette 

Formation(?) (Doelling, 1972). North-trending normal faults 

with displacements as large as 900 ft are observed in both coal 

fields (Mapel and Hail, 1959).

Paleogene lignite beds in the Goose Creek and Grouse 

Creek coal fields are present in the lower member of the Salt Lake 

Formation and in the underlying Payette Formation(?) (Doelling, 

1972). Two principal lignite beds, the Barrett and Worthington 

beds, have been reported along with numerous thin, impure beds 

(Bowen, 1913). The correlation of the Payette Formation(?) 

(within the Goose Creek and Grouse Creek coal fields) to that 

of the Payette Formation(?) (of the Snake River Valley) is 

tenuous due to possible age discrepancies and differences in the 

association of volcanic rocks between the two areas. The Payette 

Formation(?) in the Snake River Valley is associated with basalts, 

whereas the Payette Formation(?) in the Goose Creek and Grouse 

Creek coal fields is associated with rhyolites (Bowen, 1913); 

but, in this report, both occurrences are referred to as the Payette 

Formation(?).

The lower member of the Salt Lake Formation is composed 

of shale, sandstone, conglomerate, and lignite interbedded with 

white volcanic ash. Conspicuous beds of black- to dark-reddishbrown welded tuff are present in the upper half of the lower 

member (Doelling, 1972). The thickness of the lower member 

ranges from 1,200 to 1,600 ft. Carbonaceous shale zones are 

common in the lower 600 ft (Doelling, 1972). The Barrett lignite 

is the thickest and most laterally continuous lignite bed in the Salt 

Lake Formation and has reported thicknesses ranging from 14 in. 

to 9 ft. It is described as being very dirty and impure, with thick 

carbonaceous shale partings (Bowen, 1913). The Barrett lignite 

lies about 500 ft below the top of the lower member of the Salt 

Lake Formation (Mapel and Hail, 1959). Three additional lignite 

zones, described as Zones A, B, and C, from top to bottom, are 

noted in the lower member of the Salt Lake Formation. All three 

zones are composed mainly of carbonaceous shale with impure 

lignite interbedded (Doelling, 1972). Zone A is approximately 

250 ft above the Barrett lignite, Zone B is about 160 ft below the 

Barrett lignite, and Zone C is about 70 ft below Zone B (Mapel 

and Hail, 1959).

The Payette Formation (?) is composed of interbedded 

shale and volcanic ash, with occasional beds of sandstone and 

conglomerates, as well as discontinuous beds of carbonaceous 

shale and lignite (Doelling, 1972). Total thickness of the 

formation reaches 900 ft. The Worthington lignite bed lies about 

500 ft below the top of the formation (Mapel and Hail, 1959). In 

the Goose Creek field, the Worthington lignite bed crops out to 

the west of the Salt Lake Formation lignites. The Worthington 

lignite bed ranges in thickness from 3 to 5 ft. One mine was 

reported to have operated in Idaho in the Worthington lignite 

bed during 1911, after which it closed due to the high moisture 

and ash content of the lignite (Bowen, 1913). Reported analysis 

of the Worthington lignite bed on an “as received” (AR) basis 
174 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Base modified from U.S. Geological Survey DEM data, 2016.

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!

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Figure 32. Map showing Bureau of Land Management (BLM) oil and gas leases and gas exploration (dry) in the study area for the 

Southern Idaho and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (Dicken and San Juan, 2016; Gunther and others, 

2016a,b; IHS Energy Group, 2016). USGS, U.S. Geological Survey.
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BLM—Leasable commodities, energy: commodity; case disposition 

EXPLANATION

Oil and gas; closed

Oil and gas exploration (dry)

Oil and gas exploration

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

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Oil and gas; pending

Mineral-Resource Potential 175

Figure 32.—Continued
176 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Figure 33. Map showing Bureau of Land Management (BLM) geothermal leases and sites in the study area for the Southern Idaho and 

Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (Dicken and San Juan, 2016; Williams and others 2008a,b). USGS, U.S. 

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BLM—Leasable commodities, energy: commodity; case disposition

EXPLANATION

Geothermal; closed

Geothermal sites

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Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

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USGS moderate- and high-temperature systems

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Chapter B gure 35. Geothermal leases and sites.

Mineral-Resource Potential 177

Figure 33.—Continued
178 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Southeastern Oregon and North-Central Nevada 

Study Area

Southern Idaho and

Northern Nevada 

Study Area

Nevada additions

Nevada

additions

Figure 34. Map showing coal fields in the study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, Idaho, 

Nevada, and Utah (East, 2013). USGS, U.S. Geological Survey.
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Chapter B gure 36. Coal elds.

EXPLANATION

Goose Creek

Grouse Creek

Coal fields

Mineral-Resource Potential 179

Figure 34.—Continued
180 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

is 34.5 percent moisture, 18.0 percent ash, 0.63 percent total 

sulfur, 5,810 British thermal units per pound (BTU/lb), and 26.4 

percent volatile matter (Bowen, 913).

Another carbonaceous zone, the Grant zone, is noted 

about 125 ft below the top of the Payette Formation (?) 

and contains as many as six laterally discontinuous beds of 

carbonaceous shale and lignite (Mapel and Hail, 1959). 

The USGS drilled six reconnaissance holes in 

the Goose Creek coal field in Cassia County, Idaho 

(Hildebrand, 1983). Core samples were only obtained 

from three holes, due to the lignite-bearing strata being 

poorly consolidated and difficult to sample, as well as 

groundwater inflows into the drill holes. Lignite was 

observed sandwiched between Miocene volcanic ash and 

tuffs. The lignites were reported to have highly variable 

thickness and ash content.

Because of the thinness, lack of lateral continuity, 

poor quality, and regional faulting, lignite beds in the 

Salt Lake Formation and Payette Formation (?) within the 

proposed withdrawal lands area are not likely to generate 

economic interest in the future. 

Phosphate 

Sedimentary phosphate deposits (phosphorites) 

occur in strata of the Permian Phosphoria Formation and 

Mississippian Deseret Limestone, Woodman Formation, 

and Chainman Shale in the study area (Ketner, 1982; Jewell 

and others, 2000; Ketner, 2009) (fig. 35). Phosphate in the 

Phosphoria Formation is mined east of the focal area in 

southeastern Idaho and northeastern Utah, but there has 

been no production of phosphate and there are no active 

or closed phosphate leasing in the study area (table 16). 

Large phosphate resources in Idaho and elsewhere, and 

consideration of the phosphate market, preclude leasing and 

production of phosphate in the study area in coming decades. 

However, vanadium, uranium, and rare earth elements (REE) 

in trace amounts within phosphate rock are recoverable 

as byproducts during phosphate processing and may be 

targeted for extraction under appropriate market conditions. 

Therefore, a brief description of the Western Phosphate 

Field, phosphate in the study area, and byproduct vanadium, 

uranium, are provided.

The Permian Phosphoria basin, a large, epicontinental, 

marine depositional basin centered in southeastern Idaho, 

formed subsequent to the ancestral Rocky Mountain 

orogeny of Pennsylvanian and early Permian time 

(Maughan, 1994). Phosphatic sedimentary strata of the 

Phosphoria Formation accumulated in the basin. Most 

western U.S. phosphate production is from the Phosphoria 

Formation in an extensive area of phosphate mining 

referred to as the Western Phosphate Field, centered 

in southeastern Idaho (Lee, 2000). Phosphate in the 

Phosphoria Formation occurs as pelletal phosphorite that 

is interbedded with organic-matter-enriched mudstone and 

siltstone, limestone, dolomite, and chert (Piper and Link, 

2002). Surface- and underground-minable resources in 

the Western Phosphate Field in Idaho include 7.6 billion 

metric tons at 24 percent phosphorus pentoxide (P2

O5) and 

17 billion metric tons at 28 percent phosphorus pentoxide 

(P2O5), respectively. A resource of 507 billion metric tons 

of lower grade phosphatic rocks underlies the field at 

depths of more than 305 m (Moyle and Piper, 2004).

The Phosphoria basin extended at least 500 km 

westward and 700 km southwestward into Nevada, 

and phosphate is documented in sedimentary strata of 

the Phosphoria Formation and correlative units that 

are widely distributed in northern Elko and northern 

Humboldt Counties, Nevada (Ketner, 2009). Phosphorus 

concentrations in northern Nevada exposures vary mostly 

from 1 to 10 percent phosphorus pentoxide (P2O5) and to 

a maximum of 30 percent phosphorus pentoxide (P2O5) 

locally (Ketner, 2009).

Phosphorites of the Mississippian Deseret Limestone 

and Woodman Formation formed in the Antler foreland 

basin that is situated in Utah and extends into the eastern 

half of Nevada (Jewell and others, 2000). The Chainman 

Shale of Utah and Nevada also contains phosphatic beds 

(Ketner, 1982). These deposits, referred to as the Delleevent phosphorites, consist of pelletal phosphatic crusts, 

pisolitic phosphates, and detrital aggregates of ooidal and 

other types of phosphate grains (Nichols and Silberling 

1991a,b). Concentrations of phosphorus pentoxide (P2O5) in 

the Deseret Limestone range from 23 to 36 percent, and in 

the Woodman Formation, from 25 to 30 percent (Jewell and 

others, 2000).

Elevated concentrations of vanadium, uranium, 

and lanthanum occur in carbonaceous shales and 

phosphorite beds of the Phosphoria Formation. Vanadium 

concentrations average about 0.05 percent vanadium 

pentoxide (V2O5) (Cathcart and Gulbrandsen, 1973), 

which exceeds average vanadium pentoxide (V2

O5) in 

marine shales (Fischer, 1962; Maughan, 1994). Vanadium, 

uranium, and lanthanum occur in francolite, a carbonaterich fluorapatite (Cathcart, 1991; Kolodny and Luz, 1992; 

Jarvis and others, 1994). Vanadium is recovered during 

processing of phosphate for production of elemental 

phosphorus and phosphoric acid (Coleman and Clevenger, 

1967); and by the mid-1980s, byproduct vanadium 

constituted the largest domestic source (Kuck, 1985); 

yet, by 2003, domestic vanadium was solely recovered 

from various industrial waste materials such as fly ash, 

petroleum residues, spent catalysts, and vanadium-bearing 

iron slag (Magyar, 2003). Uranium also has been recovered 
Mineral-Resource Potential 181

during phosphate processing (Kouloheris, 1979; Ulrich and 

others, 2014).

Trace concentrations of lanthanum in the Meade Peak 

Member of the Phosphoria Formation in southeastern Idaho 

are 50–300 ppm, and in the Retort Tongue of the Phosphoria 

Formation are 50–350 ppm, with highest concentrations in 

southwestern Montana (Maughan, 1994). Although REEs 

have not been recovered from sedimentary phosphate deposits 

(Long and others, 2010), processing of phosphorite for 

phosphoric acid production is a potential source of byproduct 

REE (Altschuler and others, 1967; Emsbo and others, 2015). 

Occurrence of Salable Minerals

Salable commodities, mainly sand and gravel, and 

aggregate, have been produced at numerous sites in the 

study area for the Southern Idaho and Northern Nevada 

study area. There are 131 salable commodity sites (mineral 

materials sales sites) in the study area, 18 of which are 

authorized (approved) and pending, and 113 of which 

are closed or expired (fig. 36; table 16). Seven approved 

(authorized) and pending sites are sand and gravel, three 

are crushed stone, and seven are specialty stone (table 21). 

Table 21. Active mineral material sales sites in the proposed withdrawal area within the 

study area for the Southern Idaho and Northern Nevada Sagebrush Focal Area, Idaho, 

Nevada, and Utah.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey System 

(PLSS) section that includes a proposed withdrawal area]

Commodity Number of approved sites Number of pending sites

Pumice, volcanic cinder 1 0

Sand and gravel 5 1

Sand and gravel, sand 1 0

Stone, crushed and broken 3 0

Stone, specialty 7 0
182 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Southeastern Oregon and North-Central Nevada 

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Study Area

Nevada additions

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Figure 35. Map showing rocks containing phosphate in the study area for the Southern Idaho and Northern Nevada Sagebrush Focal 

Area, Nevada, Idaho, and Utah. Based on stratigraphy from Hintze and others (2000), Crafford (2007), and Lewis and others (2012).
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Chapter B gure 37. Phosphate stratigraphy.

EXPLANATION

Pennsylvanian-Permian phosphorite, shale, chert, mudstone,

 and limestone

Phosphate potential areas 

Mineral-Resource Potential 183

Figure 35.—Continued
184 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Study Area

Nevada additions

Nevada

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Figure 36. Map showing Bureau of Land Management (BLM) salable mineral commodity sites in the study area for the Southern Idaho 

and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah (Dicken and San Juan, 2016). USGS, U.S. Geological Survey.
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BLM—Salable mineral commodities: commodity; case disposition

Stone (specialty, weathered, riprap, crushed, dimension);

 authorized

Stone (specialty, weathered, riprap, crushed, dimension);

 closed, expired

Gemstone; authorized, closed expired, pending, withdrawn

Pumice, volcanic cinder; authorized

Pumice, volcanic cinder; closed

Sand and gravel; authorized, pending

Sand and gravel; closed, expired, rejected

To be defined, none; closed

EXPLANATION

Base data

USGS study area boundary

Proposed withdrawal areas

USGS study area boundary

(North-Central Idaho Study Area)

Proposed withdrawal additions

State boundaries

County boundaries

Mineral-Resource Potential 185

Figure 36.—Continued

Mineral-Resource Potential of the Nevada Additions Study 

Area 

Introduction

The Nevada additions study area consists of two 

separate groups of townships with separate U.S. Geological 

Survey (USGS) study area boundaries in Humboldt and Elko 

Counties, Nevada (figs. 18, 26). This report section addresses 

mineral potential within the USGS study area boundaries 

of the proposed withdrawal area within the Nevada 

additions study area, which is described in report section 

“Introduction.” Numerous assessment tracts cover parts of 

the Nevada additions study area but are largely within the 

study areas for the Southeastern Oregon and North-Central 

Nevada Sagebrush Focal Area and the Southern Idaho and 

Northern Sagebrush Focal Area. Those tracts are described 

in report sections “Mineral-Resource Potential of the Study 

Area for the Southeastern Oregon and North-Central Nevada 

Sagebrush Focal Area, Nevada and Oregon,” and “MineralResource Potential of the Study Area for the Southern Idaho 

and Northern Nevada Sagebrush Focal Area, Nevada, Idaho, 

and Utah.” The proposed withdrawal area within the Nevada 

additions study area encompasses 394,289 acres (~1,596km2; 

~616 mi2) managed nearly entirely by the Bureau of Land 

Management (BLM). 

Description of Geology

Paleozoic, Mesozoic, Tertiary, and Quaternary rocks are 

exposed within the proposed withdrawal area within the Nevada 

additions and USGS study area boundary. These rocks and 

related structures are shown on the geologic maps of the study 

areas for the Southeastern Oregon and North-Central Nevada 

Sagebrush Focal Area and the Southern Idaho and Northern 

Sagebrush Focal Area (figs. 19, 27), and are described in the 

report sections on those study areas. The tectonic evolution of 

the Nevada additions study area is described in report section 

“Introduction; Description of Geology.”

Mineral-Resource Potential

Mineral Potential of Locatable Minerals

Potential for undiscovered deposits of locatable mineral 

commodities (metallic locatable minerals and nonmetallic 

locatable minerals) within the Nevada additions study area 

was evaluated for the same mineral commodities as the study 

areas (gold, silver, mercury, gallium, uranium, gemstones, 

lithium, specialty clays, zeolites, diatomite, barite, copper, 

molybdenum, lead, and zinc; table1). These commodities 

were selected for evaluation on the basis of deposits in the 

Nevada additions study area, the study area for the Southern 

Oregon and North-Central Nevada Sagebrush Focal Area, and 

the study area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area. 

No assessment tracts centered within the Nevada additions 

study area were delineated and rated because of insufficient 

evidence of mineral potential in much of the area. However, 

numerous assessment tracts cover parts of the Nevada additions 

study area. Two assessment tracts with moderate potential 

which cover parts of the Nevada additions study area, Paradise 

Valley (tract ONEP04; fig. 23A) and Orovada (tract ONOG01; 

fig. 23C), are largely within the study area for the Southeast 

Oregon and North-Central Nevada Sagebrush Focal Area, and 

those tracts are described in report section “Mineral-Resource 

Potential of the Study Area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Nevada and 

Oregon.” Assessment tracts with low potential for certain 

deposit types (that is, favorable or permissive stratigraphy for 

certain deposit types) that cover parts of the Nevada additions 

study area include bedded barite (fig. 31U), Carlin-type gold 

(fig. 31S), lacustrine diatomite (fig. 31T), volcanogenic massive 

sulfide (fig. 31R), and intrusion-related deposits (fig. 31Q). 

Those tracts are described in report section “Mineral-Resource 

Potential of the Study Area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area, Nevada, Idaho, and Utah.” 

Mineral deposit types, and geology and occurrence of mineral 

deposit types for tracts which partly cover Public Land Survey 

System (PLSS) townships of the Nevada additions study 

area, are also described in report sections “Mineral-Resource 

Potential of the Study Area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area, Nevada and 

Oregon,” and “Mineral-Resource Potential of the Study Area for 

the Southern Idaho and Northern Nevada Sagebrush Focal Area, 

Nevada, Idaho, and Utah.”

Exploration and Mining Activity for Locatable 

Minerals

Metallic locatable mineral commodities that have 

been mined and explored for in and marginal to the Nevada 

additions study area include silver and gold. The western 
188 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

part of this study area is partly within the Paradise Valley 

Mining District (Humboldt County, Nevada; Tingley, 1992) 

from which minor amounts of silver and gold were produced 

from epithermal silver and gold, and other deposit types 

(tract ONEP04, Paradise Valley; fig. 23C; Vanderburg, 1938; 

Willden, 1964; Bonham and others, 1985). Although no 

production was recorded from this district, ten active and 

thousands of closed and historic lode mining claims have 

been staked in the western part (figs. 21, 22; tables 22, 23; 

Causey, 2007, 2011). 

No mining and exploration for nonmetallic locatable 

mineral commodities was recorded in the Nevada additions 

study area. However, some lode mining claims could have 

been staked for nonmetallic locatable mineral commodities 

(figs. 21, 22; tables 22, 23; Causey, 2007, 2011).

Recent, closed, and historic (pre-2011) mining claims, 

and active exploration sites for locatable mineral commodities 

cover parts of, and are marginal to, the Nevada additions study 

area (figs. 21, 22, 29, 30; tables 22, 23). There are 1,332 closed 

mining claims, 10 active mining claims, 140 closed oil and gas 

leases, 6 authorized and 3 pending oil and gas leases, 1 closed 

and 1 authorized mineral materials sales sites, and 6 closed 

surface-management plans. The closed surface-management 

plans include 5 notices and 1 plan of operations. No active 

notices or plans of operations are in this area (tables 24, 25).

Occurrence of Leasable Minerals

Leasable mineral commodities (leasable solid and fluid 

minerals) were not evaluated for assessment, but were qualitatively 

appraised for exploration and mining activity and lease status. 

No production of leasable solid minerals (coal, phosphate, and 

potash) or production of leasable fluid minerals (oil and gas, and 

geothermal) was recorded. There is no record of leases for coal, 

phosphate, potash, and geothermal, and apparently no favorable 

stratigraphy for coal, phosphate, and potash; however, oil and 

gas leases cover parts of this study area (figs. 24, 32; table 22). 

However, based on comparison to deposits of these commodities 

Table 22. Type, number, and status of mining claims, leases (coal, geothermal, non-energy solid mineral, oil and gas leases), mineral 

material sales sites, and 43 Code of Federal Regulations (CFR) 3809 plans in the proposed withdrawal area within the Nevada additions 

study area.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey System (PLSS) section that includes a proposed withdrawal area]

Type Mineral 

type

Number 

of unique 

cases

Active Authorized Pending Closed Cancelled Expired Rejected Withdrawn

Mining claims Locatable 1,332 10 — — 1,322 — — — —

Coal leases Leasable — — — — — — — — —

Geothermal leases Leasable — — — — — — — — —

Non-energy solid 

mineral leases

Leasable — — — — — — — — —

Oil and gas leases Leasable 149 — 6 3 140 — — — —

Mineral materials 

sales sites

Salable 2 — 1 — 1 — — — —

Surface-management 

plans

— 6 — — — 6 — — — —
Mineral-Resource Potential 189

elsewhere in the western United States with past or present 

production (including oil and gas fields, and geothermal fields), 

and current market conditions, neither concealed nor exposed 

deposits of these commodities are likely to be explored for or 

produced in coming decades. Oil and gas exploration, leases, and 

dry wells, are described for all four study areas in report section 

“Introduction; Leasable Minerals; Oil and Gas.” 

Occurrence of Salable Minerals

Salable mineral commodities apparently have been 

produced at very few sites in the Nevada additions study 

area. One approved salable mineral commodity site (mineral 

materials sales site) for sand and gravel is in the western part 

of the Nevada additions study area (fig. 25; table 25).

Table 23. Summary of active and closed mining claims for locatable minerals in Public Land Survey System (PLSS) sections that 

include the proposed withdrawal area within the Nevada additions study area.

 [Source: Dicken and San Juan, 2016. The number of cases is for the complete section that includes a proposed withdrawal area]

Area Active lode 

claims

Closed lode 

claims

Active placer 

claims

Closed placer 

claims Active millsites Closed millsites

Cases containing proposed 

withdrawal area

10 1,112 — — — 210

Table 24. Status and number of 43 Code of Federal Regulations (CFR) 3809 plans of operations and notices for locatable minerals in the 

proposed withdrawal area within the Nevada additions study area.

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey System (PLSS) section that includes a proposed withdrawal area]

Authorization type Number of unique 

cases

Active Authorized Pending Closed Cancelled Expired Rejected Withdrawn

Plans of operations 1 — — — 1 — — — —

Notice 5 — — — 5 — — — —

Table 25. Active mineral material sales sites in the proposed withdrawal area 

within the Nevada additions study area. 

[Source: Dicken and San Juan, 2016. The number of cases is for the complete Public Land Survey 

System (PLSS) section that includes a proposed withdrawal area]

Commodity Number of approved sites Number of pending sites

Sand and gravel 1 —
190 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Appendixes 1–5
Appendix 1. Mineral Potential Classification System

The approach to classification of the qualitative mineralresource potential for locatable minerals followed that prescribed 

in Bureau of Land Management (BLM) Manual Sections 3031 

and 3060 defined originally by Goudarzi (1984) (fig. 1-1).

Level of Potential

N. The geologic environment, the inferred geologic processes, 

and the lack of mineral occurrences do not indicate 

potential for accumulation of mineral resources.

L. The geologic environment and the inferred geologic processes 

indicate low potential for accumulation of mineral 

resources.

M. The geologic environment, the inferred geologic processes, 

and the reported mineral occurrences or valid geochemical/

geophysical anomaly indicate moderate potential for 

accumulation of mineral resources.

H. The geologic environment, the inferred geologic processes, 

the reported mineral occurrences and (or) valid 

geochemical/geophysical anomaly, and the known mines or 

deposits indicate high potential for accumulation of mineral 

resources. The “known mines and deposits” do not have 

to be within the area that is being classified, but have to be 

within the same type of geologic environment.

ND. Minerals potential not determined due to lack of useful data. 

This does not require a level of certainty qualifier.

Level of Certainty

A. The available data are insufficient and (or) cannot be 

considered as direct or indirect evidence to support or 

refute the possible existence of mineral resources within 

the respective area.

B. The available data provide indirect evidence to support or 

refute the possible existence of mineral resources.

C. The available data provide direct but quantitatively minimal 

evidence to support or refute the possible existence of 

mineral resources.

D. The available data provide abundant direct and indirect 

evidence to support or refute the possible existence of 

mineral resources.

For the determination of “no potential” use N/D. This 

class shall be seldom used, and when used it should be for a 

specific commodity only. For example, if the available data 

show that the surface and subsurface types of rock in the 

respective area are batholithic (igneous intrusive), one can 

conclude, with reasonable certainty, that the area does not 

have potential for coal.

As used in this classification, potential refers to potential 

for the presence (occurrence) of a concentration of one or 

more energy and (or) mineral resources. It does not refer to 

or imply potential for development and (or) extraction of 

the mineral resource(s). It does not imply that the potential 

concentration is or may be economic, that is, could be 

extracted profitably. 

Reference Cited

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Open-File Report 84–787, 41 p., accessed December 9, 

2015, at https://pubs.er.usgs.gov/publication/ofr84787.
Level of certainty

A B C D

N

L

M

H

Level of resource potential

H/A

M/A

L/A

H/B

M/B

L/B

H/C

M/C

L/C

H/D

M/D

L/D

N/D

High potential with 

insufficient evidence

Moderate potential 

 with insufficient 

evidence

Low potential with 

insufficient evidence

High potential with 

indirect evidence

Moderate potential 

 with indirect evidence

Low potential with 

indirect evidence

High potential with 

direct evidence

Moderate potential

with direct evidence

Low potential with 

direct evidence

High potential with 

abundant direct and

indirect evidence

Moderate potential with 

abundant direct and

indirect evidence

Low potential with 

abundant direct and

indirect evidence

No potential

Current production/significant inventor.

Significant past production.

Active or pending notices or mine plans.

Numerous active claims.

USMIN active exploration.

Prospects, geochemical anomaly,

geophysical anomaly, and (or) 

related deposit type.

Historical mining.

Historical claims.

No active notices or mine plans.

No active exploration. 

No claims.

No other applicable data.

Permissive host rocks +/- previous assessment 

Permissive host rocks +/- previous assessment

Permissive host rocks +/- previous assessment 

Few active claims.

Historical mining. 

No USMIN active exploration. 

No active notices or mine plans.

Minor past production.

Attractive exploration targets.

Active or pending notices or mine plans.

Numerous active claims.

USMIN active exploration.

Attractive exploration targets.

Active or pending notices or mine plans.

Numerous active claims.

USMIN active exploration.

Contains 2 or more of the following:

Current production/significant inventory.

Significant past production.

Active or pending notices or mine plans.

Numerous active claims.

USMIN active exploration.

Contains 1 or more of the following:

Minor past production.

Attractive exploration targets.

Active or pending notices or mine plans.

Numerous active claims.

USMIN active exploration.

Attractive exploration targets.

Active or pending notices or mine plans.

Numerous active claims.

USMIN active exploration.

Chapter A Figure H3 (Appendix fig. for all other chapters)

Contains 2 or more of the following: Contains 2 or more of the following:

Contains 1 or more of the following: Contains 1 or more of the following:

Prospects, geochemical anomaly,

geophysical anomaly, and (or) 

related deposit type.

Prospects, geochemical anomaly,

geophysical anomaly, and (or) 

related deposit type.

Prospects, geochemical anomaly,

geophysical anomaly, and (or) 

related deposit type.

Prospects, geochemical anomaly,

geophysical anomaly, and (or) 

related deposit type.

Prospects, geochemical anomaly,

geophysical anomaly, and (or) 

related deposit type.

Prospects, geochemical anomaly,

geophysical anomaly, and (or) 

related deposit type.

Prospects, geochemical anomaly,

geophysical anomaly, and (or) 

related deposit type.

Reserved for a specific type of 

resource in a well-defined area. For 

example, it is appropriate to say that 

there is no oil potential in an area 

where the only rocks present are 

unfractured Precambrian granite, 

but the term ”low” is appropriate if 

there is a slight possibility for the 

presence of resources.

Figure 1-1. Matrix showing the classification system used for qualitative mineral-resource potential for locatable minerals 

in the Sagebrush Mineral-Resource Assessment (Goudarzi, 1984) (see text for abbreviations). USMIN, U.S. Geological Survey 

Mineral Deposit Database.

Appendix 1 209
Appendix 2. Mineral-Potential Assessment Tracts for 

Locatable Minerals in the Sheldon-Hart Mountain National 

Wildlife Refuge Complex, the Southeastern Oregon and 

North-Central Nevada, the Southern Idaho and Northern 

Nevada, Sagebrush Focal Areas, Nevada, Oregon, Idaho, 

and Utah

This appendix is available online only as an Excel (.xlsx) table at http://dx.doi.org/10.3133/sir20165089B. The table lists 

mineral-potential assessment tracts for locatable minerals in the Sheldon-Hart Mountain National Wildlife Refuge Complex, 

the Southeastern Oregon and North-Central Nevada, the Southern Idaho and Northern Nevada, Sagebrush Focal Areas, Nevada, 

Oregon, Idaho, and Utah.
Appendix 3. Locatable Mineral Commodities Not 

Assessed 

Introduction

Information concerning the geologic occurrence and 

principal sources of locatable mineral commodities is 

derived principally from the Mineral Commodities Summary 

(U.S. Geological Survey, 2016). Additional information 

was gleaned from several U.S. Geological Survey datasets, 

including (1) the National Minerals Information Center 

commodities Web site (http://minerals.usgs.gov/minerals/

index.html), (2) The National Geochemical database (http://

mrdata.usgs.gov/ngdb), (3) the Mineral Resources Data 

System (MRDS; http://mrdata.usgs.gov/mrds), and (4) 

Fernette and others, (2016a). In the following commodity 

descriptions, stream sediment, and soil and rock samples 

with moderately and strongly anomalous abundances have 

elemental concentrations 8 to 15, and more than 16 times 

background values, respectively. 

The distribution of geochemical anomalies and 

commodity occurrences within the four study areas 

are described for locatable metallic and nonmetallic 

commodities that were not assessed. For metallic locatable 

mineral commodities, available data, especially the apparent 

lack of geologic environments appropriate for the occurrence 

of significant deposits, indicates negligible resource potential 

for aluminum, beryllium, bismuth, chromium, cobalt, 

iron, germanium, manganese, nickel, niobium, tantalum, 

platinum group elements, tellurium, tin, titanium, vanadium, 

and zirconium in the four study areas; consequently, no 

assessment of these commodities, and the deposit types in 

which they occur, is warranted (table 3-1). 

Most geochemical anomalies associated with metallic 

locatable mineral commodities are geographically diffuse 

and reflect only weak to moderate enrichments. Many 

of these anomalies likely reflect mineralogically and 

geochemically distinct geologic units and are therefore 

manifestations of slightly unusual rock types, not 

mineralization. Widely dispersed sediment samples with 

anomalous abundances of chromium, cobalt, or titanium may 

reflect incidental concentration of detrital, chromium-cobalttitanium-rich opaque oxide minerals derived from mafic 

eruptive rocks, including the Columbia River and Steens 

Basalts, and basalts of the Snake River Plain, especially in 

and around the study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Focal Area. 

Similarly, sediment samples with moderately high iron 

contents may reflect local concentration of magnetite 

in fluvial sediments and (or) enhanced contributions of 

magnetite from weathered, iron-enriched skarn. Sediment 

samples with anomalous nickel abundances probably reflect 

fluvial concentration of nickel-rich olivine derived from 

nearby mafic volcanic rocks. Many samples with anomalous 

geochemistry are from sample sites outside the USGS study 

area boundaries of the four study areas. Accordingly, they 

represent geochemical processes that may also have been 

operative in the four study areas, but they do not directly 

identify the presence of mineralized rocks in a particular 

study area. Another subset of geochemically anomalous 

samples is geospatially coincident with demonstrably 

mineralized or hydrothermally altered rock. However, many 

of these anomalies represent geochemical dispersion haloes 

rather than mineralized rock that corresponds directly to 

mineralization consistent with deposits of commodities of 

interest. Mineral occurrence data indicate that significant 

deposits of these commodities are not present within the 

four study areas; accordingly, the potential for significant 

undiscovered deposits is correspondingly limited.

For locatable nonmetallic mineral commodities, 

the absence of geologic environments appropriate to the 

occurrence of significant deposits of some commodities, 

including fluorspar, garnet, calcium borates, uncommon 

decorative stone, mica, sulfur, and travertine, warrant 

exclusion from assessment of deposit types that contain those 

commodities. Other nonmetallic mineral commodities with 

historically low unit value, including bentonite, gypsum, 

perlite, pozzolan, and vermiculite, either do not occur in 

deposits in the four study areas, or the quantity, quality, 

depth of cover, and distance from markets of occurrences 

of these commodities, preclude their production in coming 

decades (table 3-1).

Locatable Metallic Mineral Commodities Not 

Assessed

Aluminum—Bauxite is the principal source of 

aluminum, and domestic resources comprise only a small 

fraction of the international supply. Neither bauxite nor 

geologic terranes favorable for its occurrence are known in 

the four study areas, therefore, the potential for aluminum 

deposits is correspondingly negligible. Aluminum is reported 

as the principle commodity at a minor mineral occurrence 

just north of Scraper Springs near the southern tip of the 

study area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area (U.S. Geological Survey, 2005).
212 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Table 3-1. Locatable metallic (metals, metalliferous minerals) and nonmetallic (industrial) minerals, locatable or salable nonmetallic 

minerals, leasable minerals, salable minerals, and deposit types for locatable mineral commodities in the four USGS study areas. 

Locatable mineral commodities that were assessed are bold font.

Locatable metals/ metalliferous minerals Locatable nonmetallic (industrial) minerals Leasable 

minerals Salable minerals

Aluminum Molybdenum Barite Borates, sodium Clay (common)

Antimony Nickel Bentonite Coal Sand and gravel

Beryllium Niobium (Columbium) Borates, calcium Geothermal Stone, building

Bismuth Platinum group metals Carbon Oil and gas Stone, crushed 

(aggregate)

Carbon Rare earth elements Diamond Phosphate Stone, dimension

Chromium Silicon Diatomite Potash —

Cobalt Silver Fluorspar (fluorite) Sodium —

Copper Tantalum Travertine — —

Gallium Tellurium Vermiculite — —

Germanium Thorium Zeolite — —

Gold Tin — — —

Iron Titanium — — —

Lead Tungsten — — —

Lithium Uranium — — —

Magnesium Vanadium — — —

Manganese Zinc — — —

Mercury Zirconium — — —

Deposit types for locatable commodities

Epithermal gold-silver (mercury) Lead-zinc skarn Volcanogenic massive sulfide

Basalt-hosted sunstone Polymetallic replacement Sedimentary-exhalative lead-zinc-silver 

(SEDEX)

Porphyry copper Polymetallic veins Bedded barite

Arc-related porphyry molybdenum (low-fluorine) Distal disseminated silver-gold (antimony) Mississippi Valley-type lead and zinc

Climax-type porphyry molybdenum Carlin-type gold (silver, mercury, antimony) Orogenic low-sulfide gold-quartz vein

Molybdenum-tungsten greisen Black shale vanadium Hectorite (lithium clay)

Copper skarn Hydroallogenic uranium Specialty clay

Tungsten skarn Volcanogenic uranium Zeolites

Classification based on quality

Locatable or salable nonmetallic (industrial) minerals, 

depending on quality

Quality criteria for locatable or salable determination

Building stone Salable; locatable if uncommon

Clay, specialty Locatable (for example, ceramic grade); otherwise salable

Garnet Locatable if high quality (for example, abrasive)

Gemstone Salable; locatable if uncommon (semi- and nonprecious)

Geodes Salable; locatable if uncommon

Gypsum Locatable if high quality (for example, optical grade)

Limestone Salable; locatable if high quality (for example, chemical, cement grade)

Mica Locatable if high quality (for example, large sheets, books)

Mineral specimens Locatable if uncommon

Perlite Locatable if high quality (for example, industrial or construction grade)

Pozzolan Salable; locatable if uncommon (for example, concrete additive specifications)

Pumice Salable; locatable if one dimension ≥2 inches

Silica and silica sand Salable; locatable if uncommon or high purity (for example, fracking proppant)

Stone, decorative Locatable; otherwise salable
Antimony—Antimony is derived principally from 

sedimentary and hydrothermal vein deposits, including 

epithermal and Carlin-type gold deposits; stibnite is the 

predominant antimony ore mineral. No primary antimony ore 

has been mined in the United States during the past 5 years. 

Domestic reserves are inconsequential in a global perspective 

and the majority of the antimony used domestically comes from 

China and Russia. Some epithermal and Carlin-type gold deposits 

in and near the four study areas have anomalously high antimony 

values and may be potential sources of antimony. Rock samples 

with moderately to highly anomalous antimony contents include 

(1) a group in and near the Lone Pine district in the study area for 

the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area; (2) individual samples in the Trident Peak, 

Disaster, Opalite, and Poverty Peak districts in the study area for 

the Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Area; and (3) individual samples in or near the Edgemont, 

Elk Mountain, and Contact districts in the study area for the 

Southern Idaho and Northern Nevada Sagebrush Focal Area. 

Sediment samples with strongly anomalous antimony abundances 

include one in the Lone Pine district and groups of samples 

(1) north and east of the Star Lake deposit; and (2) extending 

northeast in and adjacent to the Independence Mountains, 

Edgemont, Aura, Mountain City, Island Mountain, Gold Basin, 

Jarbidge, and Contact districts in the study area for the Southern 

Idaho and Northern Nevada Sagebrush Focal Area. Mineralized 

occurrences that include antimony as a commodity are in the 

Opalite, National, Paradise Valley, Burner, Aura, Mountain City, 

Hicks, Alder, Charleston, Elk Mountain, Delano, and Ashbrook 

districts across northern Nevada, in the study areas for the 

Southeastern Oregon and North-Central Nevada and Southern 

Idaho and Northern Nevada Sagebrush Focal Areas (U.S. 

Geological Survey, 2005; Fernette and others, 2016a).

Beryllium—The principal domestic source of beryllium 

is the epithermal Spor Mountain deposit in Utah where the 

ore mineral betrandite is associated with highly evolved 

topaz rhyolite. Christiansen and others (1986) describe topaz 

rhyolites in the western United States, including one in the 

geographically widespread Jarbidge Rhyolite, which crops 

out in the study area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area; however, neither betrandite 

nor beryl were identified in the rhyolite. Beryllium, in beryl, 

is also contained in some pegmatite dikes, but few of these 

occurrences, which require ore to be hand-sorted, constitute 

economically viable resources. Small quantities of beryl 

were recovered from pegmatites in the Almo area (U.S. 

Geological Survey, 2005) immediately east of the study area 

for the Southern Idaho and Northern Nevada Sagebrush Focal 

Area; however, beryl-bearing pegmatite dikes have not been 

documented elsewhere in the four study areas. In the study 

area for the Southern Idaho and Northern Nevada Sagebrush 

Focal Area, a single stream-sediment sample from Salmon 

Creek, northeast of the Hicks district, has a moderately 

anomalous beryllium abundance, whereas a rock sample 

from the Delano district has a strongly anomalous beryllium 

abundance. 

Bismuth—Bismuth is principally produced as a 

byproduct of lead ore processing, but bismuth is not presently 

recovered from the residues of domestic lead ore processing. 

Globally, only two mines, one in Bolivia and the other in 

China, produce bismuth from bismuth ore (U.S. Geological 

Survey, 2016); consequently, the potential for economically 

significant bismuth resources within the four study areas 

is limited. Five widely distributed sediment samples from 

the areas in and near the Jarbidge, Elk Mountain, Snake 

Mountains and Contact districts, and east of the Independence 

Mountains districts have highly anomalous bismuth 

abundances, whereas rock samples with anomalous bismuth 

abundances are limited to single samples in the Trident Peak, 

Contact, and Delano districts, all in the study areas for the 

Southeastern Oregon and North-Central Nevada and Southern 

Idaho and Northern Nevada Sagebrush Focal Areas. Bismuth 

is reported as an incidental component of occurrences in the 

National district, Southeastern Oregon and North-Central 

Nevada Sagebrush Focal Area, and in the Lime Mountain and 

Alder districts, in the Southern Idaho and Northern Nevada 

Sagebrush Focal Area (U.S. Geological Survey, 2005). An 

additional occurrence of bismuth is found in the Charleston 

district, Southern Idaho and Northern Nevada Sagebrush Focal 

Area (Fernette and others, 2016b).

Carbon/Diamond—Diamonds are a dense, crystalline 

phase of carbon, and form in the lithospheric mantle at 

depths of about 140–190 km (Erlich and Hausel, 2002). 

They are transported upward into cratonal crust as xenoliths 

(foreign inclusions) by ultramafic magmas that often erupt 

to form “pipes,” which are somewhat similar to a volcanic 

neck. Geologic names for these crystallized intrusions 

are kimberlites and lamproites. Few of these intrusions 

contain diamond xenoliths, and only a small percentage of 

diamond-bearing kimberlites, usually those containing a high 

percentage of gem quality diamonds, are minable. Diamonds 

are also recovered from alluvium derived from erosion of 

kimberlite intrusions. No kimberlites are exposed in the four 

study areas, and no alluvial diamonds have been found in or 

near the study areas. The nearest diamonds are in colluvium 

that fills Tertiary stream channels on the western slope of 

the Sierra Nevada Mountains, California, where they were 

recovered with gold in placer mines. 

Chromium—Globally, chromium is dominantly 

produced from layered mafic-ultramafic intrusions and from 

podiform deposits associated with ophiolitic rocks. Domestic 

chromium resources are generally limited to the Stillwater 

layered mafic-ultramafic complex in Montana. The four study 

areas lack similar geologic terranes, which suggests that 

chromium deposits are unlikely therein. There are 4 sediment 

samples in the western part of the study area for the SheldonHart Mountain National Wildlife Refuge Complex Sagebrush 

Focal Area that have moderately anomalous chromium 

abundances. Among sediment samples from the study area for 

the Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Area, 6 samples from in and near the Trident Peak and 

Disaster districts and 1 sample from the Santa Rosa Range 

Appendix 3 213
214 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

have moderately anomalous chromium abundances, whereas 

a group of 4 samples from north of Louse Canyon have 

strongly anomalous chromium abundances. Similarly, about 

10 samples from southwestern Idaho and one sample from 

Bruneau Canyon, in the study area for the Southern Idaho 

and Northern Nevada Sagebrush Focal Area, have moderately 

anomalous chromium abundances. Chromium abundances for 

samples from northeast Nevada are analytically incompatible 

with other data and were not evaluated. The four study areas 

include only one rock sample, from south of the Delano 

district in the study area for the Southern Idaho and Northern 

Nevada Sagebrush Focal Area, with moderately anomalous 

chromium content. An insignificant prospect in the study area 

for the Sheldon-Hart Mountain National Wildlife Refuge 

Complex Sagebrush Focal Area has chromium, cobalt, nickel, 

and platinum as minor constituents (U.S. Geological Survey, 

2005; Fernette and others, 2016a).

Cobalt—Cobalt is mostly derived as a byproduct from 

sediment-hosted stratiform copper, laterite, sedimentary 

exhalative (SEDEX), or layered mafic-ultramafic complex 

deposits. Only the sedimentary exhalative environment is 

present, although sparingly, within the four study areas, and 

therefore, potential for associated cobalt deposits is limited. 

There are 2 sediment samples with moderately anomalous 

cobalt abundances that are from near the center of the study 

area for the Sheldon-Hart Mountain National Wildlife Refuge 

Complex Sagebrush Focal Area, 1 sample is from north of 

the Disaster district in the study area for the Southeastern 

Oregon and North-Central Nevada Sagebrush Focal Area, 

and 2 samples are from the western part of the study area for 

the Southern Idaho and Northern Nevada Sagebrush Focal 

Area, which also includes 1 sample with a strongly anomalous 

cobalt abundance. None of the analyzed rock samples contains 

moderately or strongly anomalous cobalt abundances. In 

addition to its occurrence in the minor prospect described 

above, cobalt is a minor constituent of mineralized rock 

identified at a small prospect in the southwest part of the study 

area for the Southern Idaho and Northern Nevada Sagebrush 

Focal Area (U.S. Geological Survey, 2005).

Germanium—Germanium is principally derived as 

a byproduct of zinc ore processing. Zinc ore and sphalerite 

from the sedimentary exhalative deposit at Red Dog, Alaska, 

and from select Mississippi Valley-type deposits in Tennessee, 

are presently the sole domestic sources of germanium; these 

sources constitute a very small fraction of global germanium 

production. Historically, zinc production from the four 

study areas, largely limited to northern Nevada, is relatively 

minor and is restricted to skarn and polymetallic vein and 

replacement deposits. Given the relatively small size of these 

deposits, their relatively insignificant sphalerite content, 

large quantities of germanium-bearing sphalerite in deposits 

located in Alaska and Tennessee, and dominance of the global 

germanium markets by international suppliers, small skarn and 

polymetallic deposits in the four study areas probably do not 

contain economically significant germanium deposits. Streamsediment data do not include high germanium abundances, 

no rock samples contain high germanium abundances, nor 

is germanium described as a constituent of mineralized 

occurrences within any of the four study areas (U.S. 

Geological Survey, 2005).

Iron—Domestic iron ore production constitutes 

about 2 percent of worldwide production and is relatively 

inconsequential in a global context. Banded iron formation 

mines in Michigan and Minnesota dominate domestic 

production. The study areas lack banded iron formations, but 

small bodies of magnetite-rich skarn are present. However, 

these skarn deposits, including those associated with the 

granodiorite of the Contact Mining District (U.S. Geological 

Survey, 2005), are inconsequential relative to deposits in 

Michigan and Minnesota and do not constitute a significant 

resource. No analyzed rock or sediment samples contain 

strongly anomalous iron contents. Isolated iron-enriched 

mineral occurrences are present at several sites in and adjacent 

to the four study areas, but iron is not the primary commodity 

of interest among these occurrences. Scattered occurrences 

of volumetrically insignificant iron-rich rock have been 

identified in or near the Lone Pine, Rebel Creek, National, 

Paradise Valley, Cornucopia, Aura, Independence Mountains, 

Alder, and Contact districts in association with small placer, 

epithermal, skarn, and polymetallic vein deposits in which 

iron-rich gangue minerals may be abundant (U.S. Geological 

Survey, 2005). Additional, isolated occurrences of minor 

amounts of iron are scattered in and around the Disaster and 

Contact districts in the study area for the Southeastern Oregon 

and North-Central Nevada and Southern Idaho and Northern 

Nevada Sagebrush Focal Areas, respectively (Fernette and 

others, 2016a).

Magnesium—Magnesium is produced from seawater 

and brines, as well as from magnesium minerals such as 

magnesite, dolomite, brucite, and olivine (Kramer, 1985). 

Magnesium is produced from magnesite, brucite, and 

dolomite, in Nevada, but these mines are located south of the 

four study areas. In Utah, brines from the Great Salt Lake are 

processed for magnesium, but these deposits and facilities are 

outside the study area for the Southern Idaho and Northern 

Nevada Focal Area (Bray 2016a,b).

Manganese—Manganese is primarily derived from a 

variety of sediment- and volcanic-hosted deposits and from 

deep-sea nodules. Domestically, no ore principally mined 

for manganese has been produced in more than 45 years; the 

majority of domestically consumed manganese is derived from 

South Africa or Ukraine. No rock samples from in or near the 

four study areas contain moderately or strongly anomalous 

manganese abundances. Clusters of sediment samples with 

moderately to highly anomalous manganese abundances are 

restricted to an area in the eastern part of the study area for the 

Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Focal Area and a broad area west of the Bull Run 

Mountains, in north-central Nevada. Most mineral occurrences 

that include manganese as a commodity are poorly 

characterized and restricted to northern Nevada; these include 

occurrences in and near the Opalite and Poverty Peak districts 
in the study area for the Southeastern Oregon and NorthCentral Nevada Sagebrush Focal Area and Aura, Independence 

Mountains, Mountain City, Hicks, Elk Mountain, Contact, and 

Delano districts in the study area for the Southern Idaho and 

Northern Nevada Sagebrush Focal Areas (U.S. Geological 

Survey, 2005). In the Scraper Springs area (tract INOR14, 

Scraper Springs) and Alder districts, Southern Idaho and 

Northern Nevada Sagebrush Focal Area, manganese is also 

reported as a minor commodity (Fernette and others, 2016a).

Nickel—Nickel is principally derived from mafic-ultramafic 

complex intrusions and laterites. Domestic production is limited 

to one mine in Michigan and represents an inconsequential 

contribution to world nickel production. The geologic setting of 

the three Sagebrush Focal Areas includes neither mafic-ultramafic 

complex intrusions nor laterites. Sediment samples that have 

moderately or strongly anomalous nickel contents are scarce. 

The west part of the study area for the Sheldon-Hart Mountain 

National Wildlife Refuge Complex Sagebrush Area includes 

a small group of moderately to strongly nickel-anomalous 

sediment samples and six moderately anomalous samples are 

scattered across the study area for the Southeastern Oregon 

and North-Central Nevada, and Southern Idaho and Northern 

Nevada Sagebrush Focal Areas. Within the study area for the 

Southeastern Oregon and North-Central Nevada Sagebrush Focal 

Area, several rock samples from the Poverty Peak district contain 

moderately to strongly anomalous nickel abundances. In addition 

to its occurrence in the minor prospect described above, nickel is 

reported as an accompanying commodity in a small prospect in the 

study area for the Southern Idaho and Northern Nevada Sagebrush 

Focal Area, West of the Bull Run Mountains (U.S. Geological 

Survey, 2005).

Niobium and tantalum—See “Rare earth elements 

(REE), niobium, and tantalum.” 

Platinum group elements—The platinum group 

elements (PGE) are mined from deposits in mafic and 

ultramafic layered intrusions. The Bushveld Complex in South 

Africa is the world’s major producer of PGE ore; domestic 

production, very minor by comparison, is from the Stillwater 

Complex in Montana. The four study areas do not contain 

mafic-ultramafic intrusive complexes. Incomplete geochemical 

data indicate that neither sediment nor rock samples from 

the four study areas include anomalous PGE concentrations. 

Platinum is described as a secondary commodity of the 

Stillwater Complex described above (U.S. Geological Survey, 

2005).

Rare earth elements (REE), niobium, and tantalum—The rare earth elements (REE) include the 

15 lanthanoid elements, plus yttrium and scandium, which 

are commonly regarded as REE because they have similar 

chemical and physical properties and affinities with the 

lanthanoids (Van Gosen and others, 2014). Niobium 

(columbium) and tantalum are considered together with the 

REE because they often co-occur in similar host-rock types 

and minerals (Schulz and Papp, 2014).

Globally, ore-grade concentrations of REE, niobium, and 

tantalum are most commonly found in carbonatites, alkaline 

igneous rocks, and pegmatite dikes, including weatheringrelated deposits associated with each of these rock types (such as 

placers, laterites, and clay accumulations), as well as sedimentary 

phosphate deposits, all of which are rare or unknown in the four 

study areas. Domestically, REE are currently mined from only 

one deposit at Mountain Pass, California (Gambogi, 2016a,b). 

Domestic production of niobium or tantalum has not been reported 

since 1959 (Papp, 2016a). World production of REE has been 

dominated by ion-absorption clay deposits in southern China 

since the late 1990s, while niobium production is primarily from 

carbonatite deposits in Brazil, and tantalum mostly from sources 

in Congo (Kinshasa) and Rwanda. The global supply of REE will 

likely be derived from China in the near future. World resources 

of niobium and tantalum are considered adequate (Gambogi, 

2016a,b; Papp, 2016a,b).

REE, niobium, and tantalum have not been identified as 

economically recoverable commodities in mineral occurrences 

in the four study areas. Neither notable concentrations nor 

current exploration activities are related to these commodities. 

REE was reportedly associated with gallium mineralization at 

the Cordero gallium deposit, located in the McDermitt Caldera 

Complex, but no gallium or REE resources or production 

was recorded (the property is now a silver-gold exploration 

target; Silver Predator Corp., 2015). Elevated REE, niobium, 

and tantalum abundances occur in 9 stream-sediment and 2 

rock geochemical samples within the four study areas (Smith 

and others, 2016). There are 9 stream-sediment samples with 

moderately anomalous REE concentrations that are scattered 

across the Nevada parts of the four study areas. These samples 

are isolated, single-point anomalies with low to moderate 

concentrations of REE, niobium, or tantalum. 

Silicon—Silica (SiO2), in quartz veins, and quartz in 

quartzite, sandstone, and pegmatites, is used to produce silicon 

ferroalloys and silicon metal. Manufacture of silica and silicon 

requires high-purity feedstock and deposits with more than 98 

percent SiO2 are the preferred resources (Murphy and Brown, 

1985). None of the principal producers of silicon alloys or 

silicon metal have operations within the four study areas 

(Schnebele, 2016). In Oregon, silica resources are in quartz 

replacement deposits and quartzofeldspathic sands, which 

are mined for glass manufacture and construction sand from 

locations outside the study areas (Geitgey, 1989).

Tellurium—Most tellurium is produced as a byproduct 

of copper ore milling and refining; recovery from copper 

anode slimes constitutes its dominant source. Tellurium is also 

moderately to highly enriched in epithermal precious metal 

deposits but is seldom recovered from the associated ore. 

Historically, copper production from the four study areas has 

been moderate; copper resources in the Contact district within 

the study area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area constitute additional ore from which 

byproduct tellurium could be recovered. No rock samples 

with moderately or strongly anomalous tellurium abundances 

are present within the study areas. Sediment samples with 

moderately anomalous tellurium abundances, and one sample 

with a strongly anomalous abundance, are restricted to the 

Appendix 3 215
216 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Montana Mountains and widely spaced sites in and adjacent 

to the Santa Rosa Mountains, in the southeast part of the study 

area for the Southeastern Oregon and North-Central Nevada 

Sagebrush Focal Area. Tellurium resource potential in the four 

study areas is likely restricted to future copper production and 

the economics of tellurium byproduct recovery. The USMIN 

database (Fernette and others, 2016) identifies one isolated 

mineral occurrence, in the Contact district, Southern Idaho 

and Northern Nevada Sagebrush Focal Area, that includes 

tellurium as a minor commodity.

Thorium—Thorium is a radioactive element used in 

limited quantities in a number of industrial applications such 

as specialized metal, ceramics, and optics manufacturing 

(Gambogi and Aquino, 2013). The world demand for thorium 

is so low that thorium is not mined as a primary product. 

Research into the use of thorium as a fuel in nuclear reactors 

has been ongoing for at least 50 years. Should commercial 

thorium-fueled nuclear reactors be developed, world demand 

would significantly increase. The most likely source of 

thorium is as a coproduct of REE mining (Van Gosen and 

Tulsidas, 2016). Within the four study areas, no mineral 

deposits of the type that would potentially produce coproduct 

thorium are known.

No thorium production was recorded, and one thorium 

occurrence is in the study area for the Southeast Oregon and 

North-Central Nevada Sagebrush Focal Area (U.S. Geological 

Survey, 2005). Description of the occurrence also includes 

uranium and beryllium as commodities and appears to be part 

of a cluster of pegmatite deposits in Oligocene granites (Lewis 

and others, 2012). This deposit cluster includes the City of 

Rocks deposit from which a small amount of feldspar, but 

no thorium or uranium, was mined (Lesure, 1963). Thoriumbearing pegmatites have low mineral-resource potential unless 

thorium is further concentrated, most notably into heavy 

mineral sand deposits (Anderson and Savage, 1964: Van 

Gosen and Tulsidas, 2016). 

Tin—Tin ore forms in veins, disseminations, and skarns. 

Many deposits are associated with highly evolved magmatic 

systems, although more than half of the world’s tin is produced 

from placer deposits associated with hard-rock lode deposits. 

Domestic tin production has never been significant and no 

tin ore has been mined in the United States since 1993. Two 

rock samples with moderately anomalous tin abundances 

are restricted to the National district and a site south of the 

Elk Mountain district, in the study area for the Southeastern 

Oregon and North-Central Nevada, and Southern Idaho and 

Northern Nevada Sagebrush Focal Areas, respectively. Three 

clusters of sediment samples with moderately or strongly 

anomalous tin abundances include those in and near Owyhee 

Canyon in southeast Oregon and southwest Idaho, a set east 

of the Charleston district, and a group in extreme northwest 

Utah. Isolated samples with moderately or strongly anomalous 

tin abundances include single samples southwest of the 

National district, near the northeast tip of the study area for the 

Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Area, in the Gold basin district, west of the Elk Mountain 

district, and in the Burner district. Tin is reported as an 

incidental constituent of the polymetallic Cleveland deposit in 

the Delano Mountains, Southern Idaho and Northern Nevada 

Sagebrush Focal Area (U.S. Geological Survey, 2005).

Titanium—Most titanium is produced from ilmenite or 

rutile. Principal geologic sources for these two minerals are maficultramafic layered intrusive complexes, anorthosite intrusions, 

iron-oxide-apatite deposits, and placer deposits. In a global 

context, domestic production from two operations, in Virginia 

and Florida, is minor. The four study areas lack the geologic 

environments conducive to titanium deposits. In the study area for 

the Sheldon-Hart Mountain National Wildlife Refuge Complex 

Sagebrush Area, a single sediment sample from the Lone Pine 

district contains strongly anomalous titanium abundance, and 

several nearby samples and a group located north and east of 

the nearby Virgin Valley district contain moderately anomalous 

titanium abundances. Another small cluster of sediment samples 

with anomalous titanium abundances is west of the Bilk Creek 

Mountains in the study area for the Southeastern Oregon and 

North-Central Nevada Sagebrush Focal Area. About a dozen 

additional sediment samples with moderately anomalous titanium 

abundances are scattered across the study area for the Southeastern 

Oregon and North-Central Nevada and Southern Idaho and 

Northern Nevada Sagebrush Focal Areas. The study areas contain 

no rock samples with anomalous titanium contents. Titanium, 

zirconium, and fluorite are reported as incidental constituents of 

a minor mineral occurrence in the Disaster district, within the 

study area for the Southeastern Oregon and North-Central Nevada 

Sagebrush Focal Area, and titanium is reported as the primary 

commodity of a small prospect at Willies Point in the study area 

for the Southern Idaho and Northern Nevada Sagebrush Focal 

Area (U.S. Geological Survey, 2005).

Vanadium—Vanadium is not recovered as a primary 

commodity but rather as a byproduct from phosphate rock, 

some black shale deposits, uranium ore, and as a constituent 

of titanomagnetite. The United States obtains vanadium from 

foreign sources and presently has reserves that are minor in a 

global context. Some shale horizons within the four study areas 

are prospective sources of vanadium; however, no rock samples 

from within the study areas have moderate or strongly anomalous 

vanadium contents. Clustered groups of sediment samples with 

elevated vanadium abundances are limited to 1 highly anomalous 

sample and 10 moderately anomalous samples from north and 

southeast of the Lone Pine district, respectively, in and adjacent to 

the study area for the Sheldon-Hart Mountain National Wildlife 

Refuge Complex Sagebrush Focal Area, and a large group of 

moderately anomalous samples in and adjacent to the west edge 

of the study area for the Southeastern Oregon and North-Central 

Nevada Sagebrush Focal Area. There are 4 additional sediment 

samples with moderately anomalous vanadium abundances that 

are irregularly distributed across the study area for the Southern 

Idaho and Northern Nevada Sagebrush Focal Area. A northtrending array of outcrops in the study area for the Southern Idaho 

and Northern Nevada Sagebrush Focal Area is underlain by the 

Phosphoria Formation that includes occurrences with vanadium as 

a principal commodity (Fernette and others, 2016a).
Zirconium—Zirconium, from zircon, is principally 

derived as a byproduct from heavy mineral sands processed for 

their titanium or tin mineral content. Lack of data for domestic 

zirconium production, the small contribution of domestic titanium 

resources relative to global production, suggests that domestic 

zirconium production is similarly small; domestic zirconium 

mining is limited to beach sand operations in Florida, Georgia, 

and Virginia. No rock samples from the study areas contain 

anomalous zirconium abundances. A cluster of sediment samples 

from southwest Idaho in the west part of the study area for the 

Southern Idaho and Northern Nevada Sagebrush Focal Area, and a 

smaller subset of samples from the east part of the study area for 

the Southeastern Oregon and North-Central Nevada Sagebrush 

Focal Area, contain moderately to highly anomalous zirconium 

abundances. These elevated zirconium abundances may reflect 

mechanical concentration of zircon derived from high-silica 

rhyolite tuffs that crop out extensively in the southern Snake River 

Plain area. A single sediment sample from the Charleston district 

also contains a moderately anomalous zirconium abundance. 

Zirconium is reported as a minor constituent in the small prospect 

in the Disaster district (U.S. Geological Survey, 2005).

Locatable Nonmetallic Mineral Commodities 

Not Assessed

Bentonite—Bentonite is a smectite clay used for 

drilling mud, pet waste absorbents, foundry sand, and iron 

ore pelletizing (Flanagan, 2016). The sodium end member is 

called a “swelling clay” and is mined largely for use in drilling 

muds; calcium-bentonite is also mined for adsorbents and 

water treatment and filtering (Ampian, 1985). In Nevada, Kent 

Exploration and Senator Minerals have a surface bentonite 

deposit in Elko County, with an estimated 1.9 million short 

tons of high-quality calcium bentonite (U.S. Geological 

Survey, 2015a); this deposit is outside the USGS study area 

boundary. Bentonite deposits in Oregon are outside the study 

areas (Geitgey, 1989). Some Wilderness Study Areas in 

both Oregon and Nevada have moderate to low potential for 

undiscovered bentonite resources, but these areas are outside 

the study areas (Conrad, 1990; Diggles, 1991).

Calcium Borates—The bulk of calcium borate 

resources is comprised of the minerals ulexite, a sodiumcalcium borate, and colemenite, a calcium borate. Borates are 

used in ceramics, specialty glasses, fertilizers, and detergents, 

and ulexite is used in the specialty glass and ceramics 

industries (Crangle, 2016a). The majority of domestic borate 

resources are from dry lake beds in the Mojave Desert of 

California, although there is a low-grade colemenite deposit 

in Clark County, Nevada (Lyday, 1985). In Oregon, surface 

efflorescences of borate minerals have been found near Borax 

Lake in southern Harney County, which is outside the USGS 

study area boundary (Geitgey, 1989). 

Building Stone—The U.S. Geological Survey 

commodity summaries do not include “building stone,” 

instead they refer to “dimension stone” and “crushed stone.” 

The Maryland Geological Survey provides the following 

definition: “A building stone is defined as any massive, 

dense rock suitable for use in construction. Whether igneous, 

metamorphic or sedimentary, a building stone is chosen for 

its properties of durability, attractiveness, and economy. A 

dimension stone is a building stone that is often quarried and 

prepared in blocks according to specifications. A decorative 

stone is a stone that can be quarried, cut or carved and is most 

highly valued for its pleasing appearance. It is more often 

used in interior construction for decoration and monuments 

than as standard building stone” (Kruff and Brooks, 1990). 

The British Geological Survey notes that “Building stone is 

also commonly referred to as ‘Dimension Stone’ in many 

countries” (British Geological Survey, 2005). Hence, “building 

stone” is defined as “dimension stone” for the purpose of this 

description.

In 2015, dimension stone was mined from quarries in 34 

states. Texas, Indiana, Wisconsin, Massachusetts, and Georgia 

account for 66 percent of production. Limestone, granite, 

and sandstone are the primary rock types of this commodity 

(Dolley, 2015). Split dimension stone is produced in Clark and 

White Pine Counties, Nevada (U.S. Geological Survey, 2004), 

for use as flagstone, ashlar, boulders, crushed landscape rock, 

and other types of uncut building stone. These quarries are 

outside the four study areas. In Idaho, quarries in Bonneville 

and Cassia Counties produce travertine, quartzite, and Oakley 

stone (micaceous quartzite) for use as dimension stone. The 

quarries in Cassia County are outside the study area for the 

Southern Idaho and Northern Nevada Sagebrush Focal Area 

(Fernette and others, 2016a). In Utah, the Oakley Mountain 

Corporation and Sawtooth Stone LLC operate dimension stone 

quarries in Box Elder County; both quarries are at the edge of 

the study area for the Southern Idaho and Northern Nevada 

Sagebrush Focal Area. Approximately 18 suppliers and 

quarries for dimension stone are in Oregon, but all are on the 

western side of the state near centers of large population.

Decorative Stone, Uncommon—See “Limestone” 

and “Travertine.”

Fluorspar—Fluorspar is produced principally from 

Mississippi Valley-type deposits, limestone quarries, and 

highly evolved granitoid rocks; domestic production is 

minimal at present. Fluorspar is the principal commodity 

at the small Pavlak Mine in the Jarbidge district, Southern 

Idaho and Northern Nevada Sagebrush Focal Area. It is also 

reported in the minor prospect in the Disaster district and as 

an incidental component of mineralized rock in the Scraper 

Springs district and in the Delano district, Southern Idaho 

and Northern Nevada Sagebrush Focal Area (U.S. Geological 

Survey, 2005). As part of a fluorspar inventory of Nevada, 

Papke (1979) delineated a terrane, which extends south from 

Winnemucca, Nevada, into the southern part of the state 

that contains several dozen deposits. None of the deposits 

identified by Papke (1979) is within the four study areas.

Garnet—Garnet is produced principally from 

metamorphic rocks, and skarn and placer deposits. Domestic 

garnet production, limited to one operation in Idaho, one in 

Appendix 3 217
218 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

Montana, and two in New York, is minor in a global context. 

Garnet is reported only as a constituent of minor placer deposits 

east and north of the study area for the Southern Idaho and 

Northern Nevada Sagebrush Focal Area (U.S. Geological 

Survey, 2005).

Gypsum—Gypsum (CaSO2·2H2O) commonly occurs in 

bedded sedimentary deposits. In the United States, gypsum has 

been mined around the Great Lakes, and in Texas, Oklahoma, and 

California (Pressler, 1985). In 2015, Oklahoma, Texas, Nevada, 

Kansas, Iowa, and Arkansas were the leading crude gypsumproducing States (Crangle, 2016b). No gypsum deposits or 

resource potential have been identified within the study areas.

Limestone—Limestone constituted 70 percent of 

the domestic market for crushed stone in 2015, and was used 

primarily for road construction and maintenance (Willet, 2016a). 

Used as such, it is a salable commodity and is mined by contract. 

In Nevada, claims for cement-grade limestone were staked near 

Wells and Wendover, but these are outside the study area for the 

Southern Idaho and Northern Nevada Sagebrush Focal Area. 

In 2011, there were six quarries for limestone crushed stone in 

Nevada, but they are outside the study area for the Sagebrush 

Focal Areas (U.S. Geological Survey, 2015a). In Idaho, there were 

six quarries for limestone crushed stone in 2011 (U.S. Geological 

Survey, 2015b), but those within the study area for the Southern 

Idaho and Northern Nevada Sagebrush Focal Area are classified as 

salable. In Oregon, limestone has been mined for agricultural lime 

and for production of cement and calcium carbide. The limestone 

deposits are located in the north and southwestern portions of the 

state and outside the study areas (Geitgey, 1989).

Limestone is also used as dimension stone and constituted 

42 percent, by tonnage, of the market in 2015. Because 

dimension stone is selected for its color, grain texture, and 

pattern, an unusual deposit with prized and distinctive 

characteristics might be designated a locatable commodity. In 

2015, Texas, Indiana, Wisconsin, Massachusetts, and Georgia 

produced 66 percent of dimension stone used in the United 

States (Dolley, 2016). No high-quality, locatable, limestone 

production is recorded in the study areas.

Mica—Natural mica (mostly muscovite and phlogopite) 

is marketed as scrap, flake, and sheet products. Domestic 

production is mostly from Georgia, North Carolina, South 

Dakota, and Virginia, where it is mined from mica schists, 

sericite schists, and pegmatites. Mica is also produced as a 

coproduct of feldspar and kaolin mining. Most domestically 

produced micas are ground to small particle sizes and used 

in drywall joint compound, oil well drilling additives, paint, 

roofing, plastics, and rubber products. Sheet mica is used in the 

manufacture of electrical and electronic equipment (Willett, 

2014, 2016b). No mica mines or areas with mica potential have 

been identified in the four study areas.

Mineral Specimens, Uncommon— Mineral 

specimens are not described because there are a few deposit 

type models for them, deposits are mostly small, markets are 

mostly small and are set by collectors and dealers, and demand 

is based entirely on appearance.

Perlite—Perlite is rhyolite volcanic glass that has 

2–5 percent water (Bolen, 2010). It is mined in the states of 

Nevada, Oregon, and Idaho, but no significant production 

is reported in the four study areas. In Oregon, the Eagles 

Nest deposit at Tucker Hill in southern Lake County has 

produced perlite for many years but is outside the USGS 

study area boundary. Other perlite occurrences in Lake 

County, Oregon (Glass Slipper, No Name, and Lucky Day 

OO), are also outside the study area for the Sheldon-Hart 

Mountain National Wildlife Refuge Complex Sagebrush Focal 

Area (Peterson, 1961; Geitgey, 1989). A perlite occurrence 

with no resource estimate was identified in the Spaulding 

Wilderness Area (inside the USGS study area boundary), and 

a moderate potential for perlite was assigned to the Alvord 

Peak Wilderness Area (outside the USGS study area boundary; 

Diggles, 1991).

Pozzolan—Pozzolans are minerals and nonmineral 

materials that have properties of hydraulic cement when 

mixed with lime (CaO). Once prepared, hydraulic cement sets, 

hardens, and remains stable underwater. Pozzolanic minerals 

and materials are derived from certain volcanic rocks and some 

industrial byproducts such as slag and fly ash (van Oss, 1997). 

Pozzolans can partially or completely substitute for Portland 

cement. Uneconomic occurrences of pozzolan have been 

identified in tuffaceous rocks in the northwestern corner of the 

Spaulding Wilderness Study Area, Oregon (inside the USGS 

study area boundary; Sawlan and others, 1994). Pozzolanic 

rocks occur throughout the Basin and Range Province in 

Nevada, Oregon, Idaho, and Utah, and deposits closest to 

markets are preferentially mined (Sawlan and others, 1994).

Pumice—Pumice is porous, low-density volcanic rock 

formed by rapid cooling of gas-rich lava. It is an industrial 

mineral commodity used mostly as aggregate in production 

of lightweight construction building block and in horticulture. 

Less common uses include abrasives, concrete aggregate 

and admixture (ingredients which modify properties of 

concrete), absorbents, filtration, laundry stone washing (for 

example, “stone washed” blue jeans; Geitgey, 1989), and road 

construction (Crangle, 2013, 2016). Most domestic resources 

of pumice are in the western United States, and, in 2015, the 

largest producers were in Oregon and Idaho. Mining is by 

open pit, usually in remote areas with few land-use conflicts. 

Pumice production is highly influenced by transportation costs, 

and alternative mineral materials such as crushed aggregate, 

diatomite, expanded shale and clay, and vermiculite, which may 

be economically competitive substitutes for pumice (Crangle, 

2016).

The main pumice mines in Oregon are in the central part 

of the state, outside the study area for the Southeastern Oregon 

and North-Central Nevada Sagebrush Focal Area and USGS 

study area boundaries. Pumice occurs as scattered fragments 

in volcanic tuff in two Wilderness Study Areas (public lands 

proposed for Wilderness designation) within the study area 

for the Southeastern Oregon and North-Central Nevada 

Sagebrush Focal Area, but these areas have been assigned low 
mineral-resource potential (Diggles, 1991). No pumice mines 

or areas with potential for pumice production occur within the 

study area boundaries in Idaho, Nevada, and Utah (Fernette and 

others, 2016a).

Sulfur—Sulfur has been mined for thousands of years, 

but demand for sulfur increased significantly in the 1800s 

when sulfuric acid became one of the most common acids 

used by industry. Sulfur is one of the few chemical elements 

that can occur in its elemental (native) form. It is found in 

volcanic strata and fumeroles, evaporate deposits, and salt 

domes. In evaporates and salt domes elemental sulfur is 

produced by bacterial reduction of anhydrite (CaSO4). Sulfur 

can also be obtained from sulfide and sulfate deposits, and 

from sour natural gas (containing H2S) where it is recovered 

at the wellhead (Morse, 1985). In recent years, compliance 

with environmental regulations has led to increased sulfur 

recovery from fossil fuels, and more than 75 percent of the 

world’s sulfur is produced at petroleum refineries, naturalgas-processing plants, and coking plants, mostly in Louisiana 

and Texas. Byproduct sulfuric acid represents 6 percent of the 

sulfur market and is produced at nonferrous metal smelters 

and roasters (Apodaca, 2013, 2016). Sulfuric acid, a critical 

component for global fertilizer and manufacturing industries, 

is the main product derived from sulfur. No sulfur production 

or sulfur deposits are recorded in the four study areas.

Travertine—Travertine is a form of calcium carbonate 

(CaCO3) deposited by mineralized waters and hot springs. It 

is used in the construction industry for tiles, slabs, and pavers, 

where color, pattern, and texture determine marketability. 

Consequently, travertine is also considered decorative stone. 

Most travertine used in the United States is imported from 

Italy, Iran, Turkey, Mexico, and Peru (Stone Contact, 2016). 

While travertine deposits are known within the four study 

areas, none have produced travertine for commercial purposes. 

These deposits are unlikely to be mined in coming decades 

because of insufficient quantity, inferior quality, and distance 

from markets.

Vermiculite—Vermiculite is a hydrous magnesiumaluminum-iron silicate with a platy cleavage similar to that of 

mica. When it is heated to 900 °C, associated water vaporizes 

into steam and expands the cleavage planes, creating a 

lightweight, chemically inert, fire-resistant material used mainly 

in the agricultural and construction industries (Tanner, 2016). 

Major deposits in the United States are in Montana, Virginia, 

and South Carolina, but the United States reserve base includes 

deposits in Wyoming, Nevada, and Colorado (Meisinger, 1985). 

No vermiculite deposits or potential for vermiculite production 

has been identified in the four study areas.

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Appendix 3 221
Appendix 4. Oil and Gas Plays and Assessment Units 

in the Sheldon-Hart Mountain National Wildlife Refuge 

Complex, the Southeastern Oregon and North-Central 

Nevada, the Southern Idaho and Northern Nevada 

Sagebrush Focal Areas, Nevada, Oregon, Idaho, and Utah, 

and the Nevada Additions

This appendix is available online only as an Excel (.xlsx) 

table at http://dx.doi.org/10.3133/sir20165089B. The table relates 

Public Land Survey System (PLSS) townships to U.S. Geological 

Survey (USGS) reports on oil and gas resource assessments 

for assessment units or plays in the Sheldon-Hart Mountain 

National Wildlife Refuge Complex, the Southeastern Oregon and 

North-Central Nevada, the Southern Idaho and Northern Nevada 

Sagebrush Focal Areas and the Nevada additions, Nevada, 

Oregon, Idaho, and Utah. If an assessment was conducted in 1995 

then the terminology used was “play.” After 1995, the terminology 

became “assessment unit” (AU). In many cases, more than one 

play or AU may be present within a given PLSS township. The 

table lists each PLSS township and the associated play or AU, 

the name of the play or AU, the related USGS publication title, 

and a link to the published USGS geologic assessment report. 

The USGS reports include many additional details regarding the 

source rocks, reservoir rocks, type of trap, reservoir properties, and 

resource potential.
Appendix 5. Dimensions of Epithermal Quartz-Adularia 

Gold-Silver Deposits in Northern Nevada

Deposit/District Approximate area (maximum 

dimensions, in kilometers) Notes References

Buckhorn 0.5 × 1.5 Area containing main open pits Monroe and others (1988), 

Google Earth (2016)

Buckhorn 3 × 4 Area containing all open pits including large 

areas of post-alteration cover rocks

Monroe and others (1988), 

Jennings (1991), Google 

Earth (2016)

Buckskin Mountain 2 × 3 Surface alteration and underlying veins Vikre (1987), Weiss and 

others (2015)

Fire Creek 1 × 2.2 Exploration area Odell and others (2015)

Goldbanks 1–3 × 7 Alteration including areas of post-alteration 

cover rocks

Ellis and Stroup (2015)

Hycroft 3 × 6 Surface and subsurface extent of alteration Wilson (2010)

High Grade (CA) 1 × 5 Mapped alteration Feinstein (2011)

Ivanhoe 1 × 2 Area encompassing surface projection of 

veins, Hollister pit, and mercury-bearing 

sinters

Smith (2014)

Jarbidge 5 × 7 Area containing major veins Schrader (1923), Atna Resources Ltd. (2016)

Midas 2 × 5 Surface projection of veins Marma and Vance (2011)

Mule Canyon 2 × 6 Area containing 6 open pits and 2 prospects John and others (2003)

National 2 × 3 Area containing mines and prospects Vikre (1985b)

Seven Troughs 2 × 8 Mapped alteration Hudson and others (2006)

Sleeper 0.6 × 1.2 Ultimate pit outline Nash and others (1995)

Tuscarora 1.5 × 1.5 Area containing major veins Castor and others (2003)

Appendix 5 223
224 Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

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Menlo Park Publishing Service Center, California

Manuscript approval date June 30, 2016

Edited by Sarah E. Nagorsen

Design and layout by Cory D. Hurd
Vikre and others—Geology and Mineral Resources of Nevada, Oregon, Idaho, and Utah

—Scientific Investigations Report 2016–5089–B, ver. 1.1

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20165089B