DOCSLIB.ORG

Characterization of Mineral Deposits in Rocks of the Triassic to Jurassic Magmatic Arc of Western Nevada and Eastern California

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Characterization of Mineral Deposits in Rocks of the Triassic to Jurassic Magmatic Arc of Western Nevada and Eastern California U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY CHARACTERIZATION OF MINERAL DEPOSITS IN ROCKS OF THE TRIASSIC TO JURASSIC MAGMATIC ARC OF WESTERN NEVADA AND EASTERN CALIFORNIA by Jeff L. Doebrich1, Larry J. Garside2, and Daniel R. Shawe3 Open-File Report 96-9 Prepared in cooperation with the Nevada Bureau of Mines and Geology This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 1996 'U.S. Geological Survey, Reno Field Office, MS 176, Mackay School of Mines, University of Nevada, Reno, Nevada 89557-0047 'Nevada Bureau of Mines and Geology, MS 178, University of Nevada, Reno, Nevada 89557-0088 'U.S. Geological Survey, Retired, 8920 West 2nd Ave., Lakewood, Colorado 80226 CONTENTS ABSTRACT ................................................................................ 1 INTRODUCTION ........................................................................... 1 PURPOSE .......................................................................... 1 METHODS ......................................................................... 2 PREVIOUS INVESTIGATIONS ........................................................ 2 ACKNOWLEDGMENTS .............................................................. 3 GEOLOGY ................................................................................ 4 METALLOGENIC EPISODES ................................................................. 6 MINERAL DEPOSIT TYPES ................................................................. 10 EARLY TO MIDDLE JURASSIC MINERAL DEPOSITS ................................... 10 Sedimentary Gypsum Deposits ..................................................... 10 MIDDLE JURASSIC MINERAL DEPOSITS ............................................. 11 Porphyry Copper Deposits ......................................................... 11 Copper Skarn Deposits ............................................................ 12 Iron Skarn Deposits .............................................................. 13 MIDDLE JURASSIC TO TERTIARY MINERAL DEPOSITS ................................ 14 Polymetallic Replacement Deposits .................................................. 14 Polymetallic and Gold Veins, Undivided ............................................. 14 Aluminosilicate Deposits .......................................................... 15 LATE JURASSIC TO CRETACEOUS MINERAL DEPOSITS ............................... 16 Low-F Porphyry Molybdenum Deposits .............................................. 16 Tungsten Skarn Deposits .......................................................... 17 Tungsten Veins ................................................................. 17 Cu-Au Quartz-Tourmaline Veins .................................................... 18 Volcanic-Hosted Magnetite Deposits ................................................. 19 CRETACEOUS TO TERTIARY MINERAL DEPOSITS .................................... 21 Zinc Skarn Deposits .............................................................. 21 Barite Veins .................................................................... 22 Uranium-Bearing Deposits ......................................................... 22 TERTIARY MINERAL DEPOSITS ..................................................... 23 Adularia-Sericite Epithermal Gold-Silver Veins ........................................ 23 Quartz-Alunite Epithermal Gold-Silver Veins .......................................... 24 ROCK GEOCHEMISTRY ............................................................ 26 Introduction .................................................................... 26 Analytical Methods .............................................................. 26 Statistics ....................................................................... 26 Conclusions .................................................................... 27 THE APPARENT ABSENCE OF VOLCANOGENIC MASSIVE SULFIDE DEPOSITS- A DISCUSSION ................................................................. 34 SUMMARY ........................................................................ 35 MINERAL SYSTEMS ....................................................................... 36 YERINGTON SUPERSYSTEM ........................................................ 36 Yerington Batholith .............................................................. 36 Yerington System ................................................................ 38 Yerington porphyry copper deposit ............................................... 38 Pumpkin Hollow iron-copper skarn deposits ........................................ 40 Ann Mason System ............................................................... 43 Ann Mason porphyry copper deposit .............................................. 43 Copper skarn deposits ......................................................... 43 Bear System .................................................................... 47 MacArthur porphyry copper deposit .............................................. 48 The Bear-Lagomarsino-Airport porphyry copper deposits ............................. 48 Yerington Supersystem ~ A Discussion .............................................. 53 THE MEADOW LAKE SYSTEM ...................................................... 54 Introduction .................................................................... 54 Geology ....................................................................... 55 Ore Deposits .................................................................... 57 Alteration ...................................................................... 58 Age of Mineralization ............................................................. 59 Geochemistry ................................................................... 59 Origin of Mineral Deposits ......................................................... 59 THE PINE NUT SYSTEM ............................................................ 60 Pine Nut Porphyry Molybdenum Deposit ............................................. 60 Tungsten Skarn Deposits .......................................................... 66 THE LUCKY BOY AND PAMLICO MINING DISTRICTS: A COMPARATIVE STUDY by Daniel R. Shawe, Holly J. Stein, Jeff L. Doebrich, and Robert O. Rye ........................ 67 Introduction .................................................................... 67 Geology ....................................................................... 67 Lucky Boy mining district ...................................................... 67 Pamlico mining district ........................................................ 69 Mineral Deposits ................................................................ 69 Lucky Boy mining district ...................................................... 69 Pamlico mining district ........................................................ 70 Geochemistry and Isotopes ......................................................... 70 Summary and Conclusions ......................................................... 73 SUMMARY AND CONCLUSIONS ............................................................ 73 REFERENCES CITED ...................................................................... 75 Appendix 1 .--Mineral Deposit Data ............................................................. 91 Appendix 2.-Rock Geochemical Data ........................................................... 97 Appendix 3.--Rock Sample Descriptions ........................................................ 101 PLATES 1. Geologic map of the Lucky Boy mining district 2. Geologic map of the Pamlico mining district ABSTRACT Mineral deposit studies in the Triassic to Jurassic magmatic arc of western Nevada and eastern California were conducted to characterize mineral deposits and systems hosted by the arc complex and to evaluate the arc complex for volcanogenic massive sulfide potential. Early to Middle Jurassic sedimentary gypsum deposits represent the oldest economic concentration of minerals in the study area. Middle Jurassic arc-related hydrothermal mineral deposit types within the complex include porphyry Cu, Cu skarn, Fe skarn, polymetallic replacement, polymetallic vein, and aluminosilicate deposits. The majority of these deposits are related to the Yerington supersystem, which comprises at least three individual mineral systems (Yerington, Ann Mason, and Bear systems), each of which produced porphyry Cu and related skarn, replacement, and vein deposits. During the Middle to Late Jurassic there was an apparent evolution from Cu-Fe porphyry-skarn systems to Mo-W porphyry-skarn systems with assock*ed Cu-Au quartz-tourmaline veins (for example, Risue Canyon and Meadow Lake mining districts). This metallogenic evolution is consistent with a maturing and thickening magmatic arc through time. However, the presence of Jurassic Mo-W systems may be a consequence of deeper erosion in these areas and may represent the eroded remnants of porphyry copper systems. Cretaceous deposit types related to emplacement of the Sierra Nevada batholith and unrelated to the evolution of the Triassic to Jurassic magmatic arc include W skarns (Gardnerville mining district), W veins, a low-F porphyry Mo deposit (Pine Nut deposit, Gardnerville mining district), and Au-Cu quartz-tourmaline veins (Peavine mining district). Tertiary
Load more

Recommended publications
  • Yerington, Nevada October 19, 2006 Book AZ Yerington, Nevada 88
    Yerington, Nevada October 19, 2006 The Honorable Board of Lyon County Commissioners met this day in regular session with the following present: Chairman Bob Milz, Vice-Chair Phyllis Hunewill, Commissioners Don Tibbals and LeRoy Goodman. Commissioner Chet Hillyard arrived after the start of the meeting. Also present: County Manager Donna Kristaponis, District Attorney Leon Aberasturi, Clerk/Treasurer Nikki Bryan and Deputy Clerk Joanne Sarkisian. 1. Review and adoption of agenda County Manager Donna Kristaponis requested that item #35 be moved to the beginning of the agenda. There was a consensus to approve the agenda as amended. ITEM # 35 WAS HEARD AT THIS TIME. 2. Appointed Official’s reports Comptroller Josh Foli distributed the quarterly financial report showing the revenues and expenditures of the County funds through September 30, 2006. The figures for the consolidated tax do not include the current amounts. This is due to the process being approximately three months in arrears. Utilities Director Mike Workman gave a report on the new infiltration well. He also stated that his department has finished addressing the items in the Moss Adams Management Audit report. Mr. Workman also feels that the Rolling A wastewater treatment plant is ahead of schedule and should have a 750,000 gallon capacity on line by the beginning of 2007. He also mentioned that the Utilities Department will be ready to go to bid on approximately 12 to 15 monitoring wells in the next four to six weeks. Mr. Workman then mentioned the water and sewer ordinances that will be presented to the Board in the very near future.
    [Show full text]
  • Josie Pearl, Prospector on Nevada's Black Rock Desert
    JUNE, 1962 40c • • • • . Author's car crossing the playa of Black Rock Desert in northwestern Nevada. On Black Rock Desert Trails When Dora Tucker and Nell Murbarger first began exploring the Black Rock country in northwestern Nevada they did not realize what a high, wide and wild country it was. On the Black Rock a hundred miles doesn't mean a thing. In the 10,000 square miles of this desert wasteland there isn't a foot of pavement nor a mile of railroad— neither gasoline station nor postoffice. Antelopes out-number human beings fifty to one. There's plenty of room here for exploring. By NELL MURBARGER Photographs by the author Map by Norton Allen S AN illustration of what the want to! Ain't nothin' there!" is known as "the Black Rock country," Black Rock country affords Thanking him, we accepted his re- the desert from which it derives its in the way of variety and con- port as a favorable omen and headed name actually is a stark white alkali trast, we made a J 50-mile loop trip out into the desert. Almost invariably playa, averaging a dozen miles in out of Gerlach last June. Our previous we find our best prowling in places width and stretching for 100 miles exploring of the region had been mostly where folks have told us there "ain't from Gerlach to Kings River. Merging in the northern and eastern sections, nothin'." imperceptibly with the Black Rock on so we hadn't the slightest idea of what Rising precipitously from the dead the southwest is the section known as we might find in the southern part.
    [Show full text]
  • Douglas County 2019-20 Tentative Budget Message
    BOARD OF COMMISSIONERS 1594 Esmeralda Avenue, Minden, Nevada 89423 COMMISSIONERS: Barry Penzel, CHAIRMAN Patrick Cates Larry Walsh, VICE-CHAIRMAN COUNTY MANAGER Dave Nelson 775-782-9821 Wesley Rice John Engels DOUGLAS COUNTY 2019-20 TENTATIVE BUDGET MESSAGE The County’s tentative FY 2019-20 Operating and Capital Budget totals $128,410,503. The financial resources for the agencies that comprise the County’s budget are accounted (budgeted) for in 36 separate funds. The tentative General Fund budget totals $61,113,960 and includes 2.0% Contingency and the Ending Fund Balance is at 8.3%. Special Revenue Funds with contingency budgets have budgeted between 1.5% and 3.0% Contingency and 8.3% Ending Fund Balance. The highest overlapping tax rates in Douglas County for FY 19-20 are in the Town of Minden, Town of Gardnerville, Indian Hills GID and Topaz GID at 3.66. The County’s current tax rates for FY 2018-19 and those proposed for the tentative FY 2019-20 Budget are as follows: Fund FY 2018‐19 FY 2019‐20 Rate Rate General 0.8761 0.8761 Cooperative Extension 0.0100 0.0100 State Motor Vehicle Accident Indigent 0.0150 0.0150 State Medical Assistance to Indigents 0.0600 0.0600 Social Services 0.0337 0.0337 China Spring Youth Camp 0.0039 0.0039 911 0.0475 0.0475 Self‐Insurance Reserve 0.0075 0.0075 Ad Valorem Capital Projects 0.0500 0.0500 Western Nevada Regional Youth Center (WNRYC) 0.0080 0.0080 Preventative Road Maintenance 0.0563 0.0563 Total 1.1680 1.1680 Because of the abatement process, the County is no longer able to simply determine a rate, apply it to the assessed value and have a final revenue number.
    [Show full text]
  • Central Nevada
    University of Nevada Reno LATE CENOZOIC GEOLOGY AND TECTONICS OF STEWART AND MONTE CRISTO VALLEYS, WEST - CENTRAL NEVADA A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science .I by Mark Philip Molinari fit ; December, 1984 ii ABSTRACT Discontinuous right-normal-slip faults comprise the N30 0W trending, 45 kilometer long Stewart - Monte Cristo fault zone (SMCFZ). Initiation of the SMCFZ postdates the 15.5 to 11.0 m.y. Esmeralda Formation. Right-normal-slip >1 meter occurred on the southern segment of the SMCFZ during the 1932 Cedar Mountain earthquake (Ms= 7.2-7.3). Geomor- phic evidence supports at least three and possibly five or six surface faulting events on the southern segment during the latest Pleistocene and Holocene. Gentle folds in the Esmeralda Formation east of and sub-parallel to the SMCFZ are coeval with and genetically related to faulting. Structural development of the SMCFZ is similar to other right-lateral wrench faults and is consistent with labora- tory wrench fault models. The SMCFZ is the youngest and southeasternmost fault of a system of major late Cenozoic, left-stepping, en echelon right-slip faults in the central Walker Lane. - .~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ iii TABLE OF CONTENTS page ABSTRACT .................. S S ii INTRODUCTION . 0 0 1 0 * I Location and Extent of Study Area . S S S S 1 Regional Tectonic and Geologic Setting. S. S a * 0 1 Purpose and Scope ...... a a * a 5 Methodology . 6 Previous Work . 8 Physiography. 10 MESOZOIC STRATIGRAPHY. 13 Sedimentary Rocks . & 13 Mina Formation . 13 Luning Formation . 13 Plutonic Rocks .
    [Show full text]
  • Nevada County Welcomes You!
    Nevada County Welcomes You! From rolling western slopes to thick forests and towering peaks of the Sierra Nevada, this is Nevada County, a land of blue skies, sparkling rivers and lakes, green forests and golden opportunity. Discover this special place on earth where friendly locals preserve rich historical traditions, retain a deep sense of community and enjoy a bounteous outdoor environment. Explore the colorful streets and shops of Nevada City and Grass Valley, two of California’s most interesting Gold Rush towns. See tiny villages, such as Rough & Ready, Penn Valley and Washington, that dot the Nevada County landscape. Experience the heritage of California’s most successful gold mining region. Discover the historic mountain hamlet of Truckee, a cradle of California winter sports and world‐class center of outdoor recreation. Browse through the shops of Historic Downtown Truckee’s Commercial Row and tour Donner Memorial State Park to learn about the Donner Party’s ordeal beneath the snows of 1846. Visit museums, galleries, concerts and stage plays, climb aboard a horse drawn carriage, and sip award‐winning local wines. Attend unique community celebrations such as the Nevada County Fair, Nevada City Bicycle Classic, the Draft Horse Classic and Harvest Fair, Music in the Mountains , and Truckee Thursdays. All across Nevada County, visitors will find unique specialty shops, first‐class restaurants, award‐winning wineries and a range of lodging from historic hotels to Victorian bed and breakfast inns and mountain hideaways, all with a special brand of local friendliness and hospitality. Visit www.gonevadacounty.com for complete information on all the sites and activities of Nevada County, California! We hope you enjoy Nevada County as much as we do! Photo by Brian Lowenthal Life is good in the Northern Gold Country For a romantic country weekend, a vacation or even a lifetime, Grass Valley and Nevada City in the Northern Sierra Gold Country are colorful, vibrant communities with diversions aplenty.
    [Show full text]
  • Iidentilica2tion and Occurrence of Uranium and Vanadium Identification and Occurrence of Uranium and Vanadium Minerals from the Colorado Plateaus
    IIdentilica2tion and occurrence of uranium and Vanadium Identification and Occurrence of Uranium and Vanadium Minerals From the Colorado Plateaus c By A. D. WEEKS and M. E. THOMPSON A CONTRIBUTION TO THE GEOLOGY OF URANIUM GEOLOGICAL S U R V E Y BULL E TIN 1009-B For jeld geologists and others having few laboratory facilities.- This report concerns work done on behalf of the U. S. Atomic Energy Commission and is published with the permission of the Commission. UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1954 UNITED STATES DEPARTMENT OF THE- INTERIOR FRED A. SEATON, Secretary GEOLOGICAL SURVEY Thomas B. Nolan. Director Reprint, 1957 For sale by the Superintendent of Documents, U. S. Government Printing Ofice Washington 25, D. C. - Price 25 cents (paper cover) CONTENTS Page 13 13 13 14 14 14 15 15 15 15 16 16 17 17 17 18 18 19 20 21 21 22 23 24 25 25 26 27 28 29 29 30 30 31 32 33 33 34 35 36 37 38 39 , 40 41 42 42 1v CONTENTS Page 46 47 48 49 50 50 51 52 53 54 54 55 56 56 57 58 58 59 62 TABLES TABLE1. Optical properties of uranium minerals ______________________ 44 2. List of mine and mining district names showing county and State________________________________________---------- 60 IDENTIFICATION AND OCCURRENCE OF URANIUM AND VANADIUM MINERALS FROM THE COLORADO PLATEAUS By A. D. WEEKSand M. E. THOMPSON ABSTRACT This report, designed to make available to field geologists and others informa- tion obtained in recent investigations by the Geological Survey on identification and occurrence of uranium minerals of the Colorado Plateaus, contains descrip- tions of the physical properties, X-ray data, and in some instances results of chem- ical and spectrographic analysis of 48 uranium arid vanadium minerals.
    [Show full text]
  • Eocene–Early Miocene Paleotopography of the Sierra Nevada–Great Basin–Nevadaplano Based on Widespread Ash-Flow Tuffs and P
    Origin and Evolution of the Sierra Nevada and Walker Lane themed issue Eocene–Early Miocene paleotopography of the Sierra Nevada–Great Basin–Nevadaplano based on widespread ash-fl ow tuffs and paleovalleys Christopher D. Henry1, Nicholas H. Hinz1, James E. Faulds1, Joseph P. Colgan2, David A. John2, Elwood R. Brooks3, Elizabeth J. Cassel4, Larry J. Garside1, David A. Davis1, and Steven B. Castor1 1Nevada Bureau of Mines and Geology, University of Nevada, Reno, Nevada 89557, USA 2U.S. Geological Survey, Menlo Park, California 94025, USA 3California State University, Hayward, California 94542, USA 4Department of Earth and Environment, Franklin & Marshall College, Lancaster, Pennsylvania 17604, USA ABSTRACT the great volume of erupted tuff and its erup- eruption fl owed similar distances as the mid- tion after ~3 Ma of nearly continuous, major Cenozoic tuffs at average gradients of ~2.5–8 The distribution of Cenozoic ash-fl ow tuffs pyroclastic eruptions near its caldera that m/km. Extrapolated 200–300 km (pre-exten- in the Great Basin and the Sierra Nevada of probably fi lled in nearby topography. sion) from the Pacifi c Ocean to the central eastern California (United States) demon- Distribution of the tuff of Campbell Creek Nevada caldera belt, the lower gradient strates that the region, commonly referred and other ash-fl ow tuffs and continuity of would require elevations of only 0.5 km for to as the Nevadaplano, was an erosional paleovalleys demonstrates that (1) the Basin valley fl oors and 1.5 km for interfl uves. The highland that was drained by major west- and Range–Sierra Nevada structural and great eastward, upvalley fl ow is consistent and east-trending rivers, with a north-south topographic boundary did not exist before with recent stable isotope data that indicate paleodivide through eastern Nevada.
    [Show full text]
  • Ground-Water Resources-Reconnaissance Series Report 20
    - STATE OF NEVADA ~~~..._.....,.,.~.:RVA=rl~ AND NA.I...U~ a:~~::~...... _ __,_ Carson City_ GROUND-WATER RESOURCES-RECONNAISSANCE SERIES REPORT 20 GROUND- WATER APPRAISAL OF THE BLACK ROCK DESERT AREA NORTHWESTERN NEVADA By WILLIAM C. SINCLAIR Geologist Price $1.00 PLEASE DO NOT REMO V~ f ROM T. ':'I S OFFICE ;:: '· '. ~- GROUND-WATER RESOURCES--RECONNAISSANCE SERIES .... Report 20 =· ... GROUND-WATER APPRAISAL OF THE BLACK ROCK OESER T AREA NORTHWESTERN NEVADA by William C. Sinclair Geologist ~··· ··. Prepared cooperatively by the Geological SUrvey, U. S. Department of Interior October, 1963 FOREWORD This reconnaissance apprais;;l of the ground~water resources of the Black Rock Desert area in northwestern Nevada is the ZOth in this series of reports. Under this program, which was initiated following legislative action • in 1960, reports on the ground-water resources of some 23 Nevada valleys have been made. The present report, entitled, "Ground-Water Appraisal of the Black Rock Desert Area, Northwe$tern Nevada", was prepared by William C. Sinclair, Geologist, U. s. Geological Survey. The Black Rock Desert area, as defined in this report, differs some~ what from the valleys discussed in previous reports. The area is very large with some 9 tributary basins adjoining the extensive playa of Black Rock Desert. The estimated combined annual recharge of all the tributary basins amounts to nearly 44,000 acre-feet, but recovery of much of this total may be difficult. Water which enters into the ground water under the central playa probably will be of poor quality for irrigation. The development of good produci1>g wells in the old lake sediments underlying the central playa appears doubtful.
    [Show full text]
  • RECREATION SPECIALIST REPORT SEPTEMBER 2014 BORDERTOWN to CALIFORNIA 120 KV TRANSMISSION LINE I LIST of TABLES
    SPECIALIST REPORT: RECREATION BORDERTOWN TO CALIFORNIA 120 KV TRANSMISSION LINE PROJECT SIERRA COUNTY, CALIFORNIA AND WASHOE COUNTY, NEVADA Prepared by: Humboldt-Toiyabe National Forest Carson Ranger District 1536 South Carson Street Carson City, Nevada, 89701 Contact: Daniel Morris, Natural Resource Specialist September 2014 TABLE OF CONTENTS page 1.0 INTRODUCTION..............................................................................................................1 1.1 PURPOSE OF SPECIALIST REPORT ..............................................................................1 1.2 PROPOSED PROJECT ..................................................................................................1 1.2.1 Project Construction.....................................................................................2 1.2.2 Restoration of Project-Related Ground Disturbance ...................................7 1.2.3 Operation and Maintenance .........................................................................7 1.2.4 Design Features Common to All Alternatives .............................................7 1.3 PROPOSED ACTION AND ALTERNATIVES ...................................................................8 1.3.1 No Action Alternative ..................................................................................9 1.3.2 Action Alternatives ......................................................................................9 1.4 RECREATION RESOURCES ISSUE STATEMENT .........................................................14 2.0 AFFECTED
    [Show full text]
  • The Geology and Paleontology of Tule Springs Fossil Beds National Monument, Nevada
    The Geology and Paleontology of Tule Springs Fossil Beds National Monument, Nevada On December 19, 2014, Tule Springs Fossil Beds National Monument in Nevada was established by Congress as the 405th unit of the National Park Service to “conserve, protect, interpret, and enhance for the benefit of present and future generations the unique and nationally important paleontological, scientific, educational, and recreational resources and values of the land” (P.L. 113-291, sec. 3092). Photograph by Eric Scott, Cogstone Resource Management, Inc., used with permission. The upper Las Vegas Wash cuts through sediments formed by ancient springs and marshes that blanketed the Las Vegas Valley floor during the Pleistocene Epoch. These deposits have yielded thousands of vertebrate fossils and contain valuable information on past climatic and environmental conditions. This is Tule Springs Fossil Beds National Monument. A Brief History of Tule Springs techniques with massive earth-moving animals (Haynes, 1967). Consequently, activities. Heavy construction equipment the hypothesis that early humans coexisted Vertebrate fossils have been known carved enormous trenches into the sedi- with Pleistocene megafauna at Tule from the Las Vegas Valley for more than ments at Tule Springs to expose vertical Springs was disproven, and interest in the a century, beginning in 1903 when Josiah walls as deep as 13 meters (nearly site faded. A long intermission in scientific Spurr of the U.S. Geological Survey 43 feet!), which allowed the sediments to research followed, lasting until the 2000s reported teeth and bones in the sedi- be studied in detail. Geologist C. Vance when museum scientists conducted com- ments exposed in the wash between Corn Haynes, Jr., directed the geological inves- prehensive and systematic paleontological Creek Springs and Tule Springs (Spurr, tigations and subdivided the fossil-rich excavations of the area.
    [Show full text]
  • Carlin-Type Gold Deposits in Nevada: Critical Geologic Characteristics and Viable Models
    ©2005 Society of Economic Geologists, Inc. Economic Geology 100th Anniversary Volume pp. 451–484 Carlin-Type Gold Deposits in Nevada: Critical Geologic Characteristics and Viable Models JEAN S. CLINE,† University of Nevada, Las Vegas, 4505 Maryland Parkway, Box 454010, Las Vegas, Nevada 89154-4010 ALBERT H. HOFSTRA, Mineral Resources Program, U.S. Geological Survey, Mail Stop 973, Box 25046, Denver, Colorado 80225 JOHN L. MUNTEAN, Nevada Bureau of Mines and Geology, Mail Stop 178, University of Nevada, Reno, Nevada 89557-0088 RICHARD M. TOSDAL, AND KENNETH A. HICKEY Mineral Deposit Research Unit, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia, Canada V6T 1Z4 Abstract Carlin-type Au deposits in Nevada have huge Au endowments that have made the state, and the United States, one of the leading Au producers in the world. Forty years of mining and numerous studies have pro- vided a detailed geologic picture of the deposits, yet a comprehensive and widely accepted genetic model re- mains elusive. The genesis of the deposits has been difficult to determine owing to difficulties in identifying and analyzing the fine-grained, volumetrically minor, and common ore and gangue minerals, and because of postore weathering and oxidation. In addition, other approximately contemporaneous precious metal deposits have overprinted, or are overprinted by, Carlin-type mineralization. Recent geochronological studies have led to a consensus that the Nevada deposits formed ~42 to 36 m.y. ago, and the deposits can now be evaluated in the context of their tectonic setting. Continental rifting and deposi- tion of a passive margin sequence followed by compressional orogenies established a premineral architecture of steeply dipping fluid conduits, shallow, low dipping “traps” and reactive calcareous host rocks.
    [Show full text]
  • F I N a L Mineral Assessment Report
    BLM F I N A L MINERAL ASSESSMENT REPORT Battle Mountain District Office - Nevada J A N U A R Y 2 0 1 2 This page intentionally left blank Bureau of Land Management Mineral Assessment Report SUMMARY The Bureau of Land Management (BLM) Battle Mountain District Office (BMDO) is in the process of revising the district’s Resource Management Plan (RMP). As part of the RMP revision process, the BLM is required to prepare a Mineral Assessment Report providing information regarding mineral occurrences and potential within the BMDO Planning Area (planning area). This report provides an intermediate level of detail for mineral assessment as prescribed in BLM Manual 3060 (BLM 1994). Information presented in this report will be summarized and incorporated into an Environmental Impact Statement (EIS) for the proposed RMP and into the final RMP. The geologic history of central and southern Nevada and the planning area is very complex and includes two major cycles of sedimentation (western and eastern facies sources), episodic thrust faulting, mountain building, and associated intrusive and igneous activity. More recent geologic history includes a period of crustal extension that was accompanied by bimodal (rhyolite-basalt) volcanism, large volume caldera volcanism, and basin and range block-faulting resulting in high-levels of shallow crustal heat flow. The regional and local geologic setting has been instrumental in the location of and potential for numerous economic metallic mineral deposits in the planning area, as well as development of economic geothermal resources. MINING AND MINERAL ACTIVITY IN NEVADA Mineral exploration, particularly for gold, is an ongoing enterprise in Nevada by both operators of existing mines and by other exploration companies.
    [Show full text]