DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, DIRECTOR BTJXILETESr 347 THE AND WRANGELL MINING DISTRICTS, ALASKA BY FRED EUGENE WRIGHT AND CHARLES WILL WRIGHT WASHINGTON GOVERNMENT PRINTING OFFICE 1908 CONTENTS. Page. Preface, by Alfred H. Brooks______1___________________ 9 Introduction __._________________________________ 11 General statement _"________________________,_____ 11 Field work________________________________ 12 Maps __ 13 Literature ________'_____________________________ 14 History of mining developments- ____________!__________ 16 Ketchikan mining district______ 16 AVraugell mining district __ _________________________ IS Production _ __ 19 Geographic sketch of southeastern Alaska__________________ 21 Geography of the Ketchikan and Wruugell districts __ _____ 22 General statement _______________________________ 22 Mainland belt _______ _ __.,____________ 23 Seaward islands : 26 Climatic conditions ______ _ __ _____ 27 Timber and vegetation__ __________^.__ 30' Distribution of timber _ ____ 30 Value of timber ______ _____ ______-______ ' 31 Growth of vegetation__'_ ___________ 31 National forest________________ _____________ 32 General geology of southeastern Alaska_____ ____________ 32 General statement ________ ____ 32 Stratigraphic succession_ _ _ _____ 33 Rock formations .____ ___________ 36 Structure : _____ 38 Mineral deposits______________ : __________ 41 Geology of the Ketchikan and Wrangell mining districts__________ 43 . Geologic maps __ _ __ 43 Sedimentary rocks.____ ,. 1 ____ 45 General statement ___________ _ :__________ 45 Paleozoic strata ___ _______________________ 45 Silurian ______________________________ 45 Devonian _____________ ______________ 46 Carboniferous ___________________________ 52 Mesozoic strata______________________ _______ 57 Tertiary strata _ _ _ 59 Igneous rocks.______ : __ 61 Coast range intrusives __ 61 General description _______ _ __ __ __ 61 Average composition __.._____________________ 63 Contact metamorphism_ ___ ________ ____ 65 Dike rocks and mineralization_________________ 6S 3 4 CONTENTS. Geology of the Ketchikau and Wrangell uiiuing districts Continued. V:\gc. Igneous rocks Continued. Other intrusives ______________________________ 69 Extrusives ____________________________ 70 Greenstones ___________________________1_ 70 Andesites __________________________ 71 Basalts _________________________________ _ 72 Outline of geologic history_______________________ 73 Ore deposits________________________________ 77 General distribution of mineralization________________ 77 Coast Range intrusive belt and adjacent schists____._____ 77 Slate-greenstone belt__________________________ 78 Prince of Wales Island and the seaward islands__________ 79 Principal characteristics of ore deposits_______________ 80 General statement _________________________ 80 Vein deposits____________________________ SO Breccia veins_______________________________ 81 Lode deposits ________________________________ 82 Coutact-metainorphic deposits____________________ 83 Character of ores_________________________ 84 Copper ores ________________________________ 84 Gold ores _____________________________ sr» Ore minerals ___________:_______________________ Sf> Native minerals _____________________________ 85 Sulphides, tellurides, arsenides, etc___________________ SO Oxides, carbonates, and silicates__________________ 89 Detailed descriptions of mines and prospects___«._____________ 93 General statement ______________________ 93 Copper mines_________________________________ 93 General statement ____________ Jr_____________ 93 Hetta Inlet_________________________________ 94 General description.__________________________ 94. Geology ______________________________ 95 Ore deposits___________________________ i)r> Copper Mountain gronp.____________________ !>('» Jumbo group___ :_._________________ ____ 99 Green Monster group_______________________ 102 H'onghton group_______.._______ 103 Sultana group___________________________ 104 Corbin mine______________________________ 105 Copper City mine_________..______________ 100 Prospects on Gonld Island____________________ 107 Prospects at head of Copper Harbor______________ 107 Prospects on Hetta Mountain_______________ 108 Kasaan Peninsula.____________________________.. 108 General description.______________:__________ 108 Geology __________________________________ 110 Ore deposits___________________________.__ 11.1 Mamie mine____________________________ 112 Stevenstown mine________________________ 1.14 Mount Andrew mine______________________ 115 Uncle Sam mine__________________________ 117 Copper Queen group______________- __ - 1.17 CONTENTS. 5 Detailed descriptions of mines and prospects* Continued. Page. Copper mines Continued. Kasaan Peninsula Continued. Poor Man's group______________________ US Eagle's Nest group____________ __ US Tayjor prospect____________________ 110 Mammoth group.-_________ -__________ 110 Other prospects_________________________ 120 Karta Bay.________________________________ 122 General description_________________________ 122 Rush & Brown mine__________________________ 123 Venus group__.._____________________ 125 Goodro claims________________ ___ ___ 125 Tolstoi Bay.__________________________________ 126 General description.___________________ 126 Iron Cap group__________________________ 126 Wallace group_____________ 127 Tolstoi group_____________________________ 127 Big Five claim.____________________________ 127 Kasaan Bay prospects_____________________ _ 127 Sunny Day group________'____________________ 127 Shelton group._____^_____________________ 12S Niblack Anchorage_____________________________ 128 Genera] description____.______i_____________ 12S Niblack mine______________________________ 120 Lookout group____________________________ 131 Copper Cliff mine__________________________ 131 Wakefleld group____________________________ 132 North Arm of Moira Sound_______________________ 132 General description..______________________ 132 Cymru mine___L ___________________________ __ 132 Skowl Arm__________________________________ 134 General description____..__________________ 134 Khayyam mine___________________________ 185 Mammoth group_____________________________ 137 Gravina Island______________________________ 188 Genera] description.___________________________ 188 Prospects at Seal Bay and Dall Head______________ 188 Prospects at Vallenar Bay_____________________ 140 Duncan Canal______________________________ 1.40 Genera] description._____.___________________ 140 Portage Mountain group______________________ 141. Kupreanof group.________________:_________ 1.41 Taylor Creek prospects.:_______________________ 142 Gold mines__________________________________ 142 General statement_____________________________ 142 Thorne Arm___:______________________________ 1.43 George Inlet_______________________________ 1.40 Tongass Narrows____________________________ 151 Cleveland Peninsula.-.__________________________ 152 Twelvemile Arm__________________________ 1.58 General description__________.______________ 158 Prospects in the vicinity of Hollis_______________ 150 Prospects on Granite Mountain___.______________ 1.64 6 CONTENTS. Detailed descriptions of mines and prospects Continued. Page. Gold mines Continued. Cholmondeley Sound_____________________..___ 166 General description._______________________ 166 Prospects south of Cholmondeley Sound______ ______ 166 Prospects'at Kitkuu Bay______________ ___!______ 168 Prospects at head of Dora Bay.__.______________ 171 Dolomi_:_________________________________ 172 Prospects on south side of North Arm________________ 176 Gravina Island _______._____________________ 177 General description______________________ ___ 177 Goldstream group________:________________ 177 Heckmau group____________________:_____ 179 Moonshine group___________________________ 179 Annette Island_______________________________ 179 Dall Island_______=.________________________ 180 Baker Island_____________________________ 181 Woewodski Island _____________________________ 182 Woronkofski Island____________________________ 184 Smeatou Bay prospects-______________..________ 185 Unuk River prospects___________________________ 185 Silver, lead, and zinc mines_____..__._________________ 186 General description _____._______._______________ 186 South Arm of Cholmondeley Sound_________________ 187 Moonshine group____:__________________ 187 Groundhog and Glacier basins____________________ 1.88 Coronation Island prospects______________________ 190 Building stones_________________'___________________ 191 General statement_______________________________ 191 Marble_________________________________________ 191 Distribution ______________________~___________ 191 Necessary qualities__________________________ 192 Competitive districts____________________________ 192 Description of localities of occurrence__..___________ .1.92 Prince of Wales Island__________ ._________:__ .192 Alaska Marble Company__________________ 192 El Capitan Marble Company_________________ 195 Marble Island ____ _______-_ ____ _ 196 American Coral Marble Company______-___ 196 Revillagigedo Island-_____________ _ _____ 197 Ham Island ___________________ ____ 198 Granite ___________-______________ .______ 198 Distribution _i__________________________-_____ 198 Characteristics _____!_____________ 199 Market__________________________ _________ 199 Cement____________________ - 200 Mineral and thermal springs_____ _ __ _ 200 Future of the districts____._______________