DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, DIRECTOR 408 A RECONNAISSANCE OF SOME MINING GAMPS IN ELKO, UNDER, AND EUREKA COUNTIES, NEVADA BY WILLIAM H. EMMONS WASHINGTON GOVERNMENT PRINTING OFFICE 1910 CONTENTS. Page. Introduction.............................................................. 9 Scope of report.......................................................... 9 Field work and acknowledgments...................................... 9 Bibliography........................................................ 11 Topography, climate, and vegetation.....:............................. 12 History........................................'...,.............,.... 14 Production............................................................ 14 General geology.......................................................... 15 Sedimentary rocks..................................................... 15 Introduction...................................................... 15 Cambrian system .....................................-- - --- 1' ^ Prospect Mountain quartzite................................... 17 Eldorado limestone........................................... 17 Secret Canyon shale.......................................... 18 Hamburg limestone............................................ 18 Dunderberg shale............................................. 18 Ordovician........................................................ 18 Pogonip limestone............................................. 18 Eureka quartzite.............................................. 18 Lone Mountain limestone...................................... 18 Devonian system................................................. 19 Carboniferous system ............................................. 20 White Pine shale. ......................'...................... 20 Diamond Peak quartzite...................................... 20 Lower coal measures........................................... 20 Weber conglomerate........................................... 20 Upper coal measures.......................................... 21 Mesozoic rocks.................................................... 21 Tertiary rocks..................................................... 21 Eocene...................................................... 21 Miocene...................................................... 22 Pliocene......... I..........................:................ 22 Quaternary deposits............................................... 23 Glacial deposits..................................... v.......... 23 Alluvial deposits............................................. 23 Igneous rocks......................................................... 24 Intrusive granitic rocks............................................ 24 Distribution and composition................................... 24 Contact relations and age...................................... 27 Porphyries associated with intrusive granitic rocks................... 29 Tertiary eruptive rocks............................................ 30 Rhyolite .................................................... 30 Basalt ...................................................... 31 Andesite .................................................... 32 Dacite ....................................................... 33 Succession of the Tertiary eruptive rocks....................... 33 Age of the Tertiary eruptive rocks............................... 34 3 4 CONTENTS. General geology Continued. page. Deformation of the rocks.............................................. 35 Re'sume' of geologic history......................°....................... 37 Ore deposits.............................................................. 39 General statement...................................................... 39 Earlier deposits (Cretaceous?).......................................... 40 General statement.................................................. 40 Contact-metamorphic deposits...................................... 40 Irregular replacement deposits.in limestone.......................... 41 'Replacement veins and sheeted zones in limestone and in shale...... 42 K Fissure veins in quartzite. ............... t.......................... 42 Fissure veins in the older intrusive rocks........................... 43 Later deposits (Miocene)................................................ 43 Fissure veins and sheeted zones in andesite.......................... 44 Fissure veins and fracture zones in rhyolite......................... 44 Placer deposits. ........................................................... 45 Prospecting............................................................ 46 Mountain ranges and mining districts........................................ 47* Owyhee Bluffs......................................................... 47 General features................................................... 47 Geologic features................................................... 47 Midas or Gold Circle district........................................ 48 Location and history........................................... 48 Geology...................................................... 48 General outline............................................ 48 Hydrothermal metapmorphism............................. 49 Fissuring and faulting.................:.................... 50 Ore deposits.................................v................ General features........................................... Prospecting the lodes...................................... Ore shoots................................................... 'Secondary enrichment...................................... Re'sume' of geology............................................. Mine descriptions............................................. Rex mine..................:............................. Gold Crown lode........................................... St. Paul-Banner lode......................................... GoldBn Chariot claim...................................... Esmeralda mine........................................... Water Witch mine............................................. Elko Prince lode........................................... Midas mine................................................ Gold Circle claim.......................................... Belvoir claim............................................. Eastern Star mine......................................... Independence Range.................................................. General features.................................................... Tuscarora........................................................... History...............................l........................ Ore deposits......................... ^........................ Silver lodes............................................... Gold deposits....................................'.......... Falcon mine...................................................... Cornucopia................................:.................-..-. 63 Good Hope district................................................. 65 CONTENTS. 5 Mountain ranges and mining districts Continued. Page. Burner Hills........................................................... 66 General features................................................... 66 Mint mine......................................................... 67 Centennial Range..................................................... 67 General features................................................... 67 Ore deposits...................................................... 69 Lime Mountain................................................... 70 Columbia and Aura............................................... 71 General statement. ........................................... 71 Mine descriptions............................................. 71 Infidel mine.............................................. 71 Big Four mine............................................ 72 Columbia Queen mine..................................... ^72 Blue Jacket mine......................................... 72 Jack Pot mine............................................ 73 California mine................ -- -.-.--.-.---.-.----..--. 74 Tiger lode................................................ 74 Humboldt mine........................................... 74 Polaris mine.. .....................................*...... 74 Aura King mine.......................................... 74 Edgemont......................................................... 75 Lucky Girl group.............................................. 75 Bull Run mine.................................:............. 79 Mountain City. .................................................. 80 Location and history........................................... 80 Geology...................................................... 80 Ore deposits.................................................. 81 Mine descriptions............................................. 82 Protection mine ............................................ 82 Resurrection mine........................................ 82 Nelson mine...........:.................................. 83 Mountain City mine,...................................... 83 Van Duzer Creek placers.......................................... 84 Lone Mountain....................................................... 84 Cortez Range between the Carlin and Dalton peaks...................... 86 General features..................................................