Kotsina-Chitina Region, Alaska
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DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEOKGE OT.IS SMITH, DIRECTOR 374 MINERAL RESOURCES OF THE KOTSINA-CHITINA REGION, ALASKA BY FRED PL MOFFIT AND A. G. MADDREN WASHINGTON GOVERNMENT PRINTING OFFICE 1909 CONTENTS. Page. Preface, by Alfred H. Brooks _______________________ . 7 Introduction'_ _ 9 Geography and history , 11 Position __ ' 1.1 Trails and routes______ ____________ __________ 13 Vegetation and climatic conditions____________________ 18 History ________ _______._________________..__ 19 General geology _ _ 20 Introduction_____ 20 Undetermined rocks on Kotslna River_____:______________ 28 Nikolai greenstone ____________________ 23 Description ________________________________ 23 Occurrence and distribution__ _ ________________ 24 Structure of the greenstone______________________ 24 Age of the greenstone__ ____________________ 24 Chitistone limestone (Triassic)______________________ 25 Description _ __ _ _____ 25 Occurrence and distribution___________________^__ 25 Thickness of Chitistone limestone__________________ 26 Age of the Chitistone limestone____________________ 20 Triassic limestones and shales____________________ 28 Description ______________ ________________ 28 Occurrence and distribution _ _ ___________ 29 Fossils__________:_____________..____________ 29 Disturbances following deposition of Triassic _ __________ 29 Kennicott formation _________ _____________________ 30 Description _ _ ________ 30 Occurrence and distribution_______________________ 30 Age of Kennicott formation_____________________ 31 Post-Keunicott disturbance and erosion.__________________ 32 Coal-bearing rocks__________I__________._________ 32 Tertiary volcanic series_________________________ 33 Description and occurrence _ __________________ 33 Thickness of volcanic series______________.________ 33 Age of volcanic series- ___ _ ________________ 34 Igneous rocks . _____ 34. Preliminary statement ___________^______________ 34 Granular rocks in the unmetamorphosed sediments________ 34 Porphyries in the unmetamorphosed sediments___________ 35 Andesite cutting the Triassic____________________ 35 Intrusive rocks in Tertiary volcanic series______________ 36 Andesite flows__.____________: ______________ 36 3 4 CONTENTS. General geology Continued. Page. Faults ___.________________________________ 37 Pleistocene and Recent deposits______________________ 37 Introduction ______ ________________________ 37 Present features____________________________ 3S -Pre-Pleistocene land surface___________________._ 38 Erosion and deposition during Pleistocene and Recent time__ 39 Character of the valley-plain deposits__'._____________________ 41 Economic geology__________________________________'_ 42 General statement _______ ________________________ 42 Copper ______'________,___________-__________ 42 'The copper minerals- _____________________.__ 44 Preliminary statement ____________________ 44 Native copper_________________________ 44 Cuprite ____________________________.____ 45 Tenorite ________ ___________________ 45 Chalcocite ____-+ - ___________________________ 45 Bornite ____________________:__________ 46 Chalcopyrite _______________"____________ 46 Malachite _____________:_____1_________ 46 Azurite ________________________________ 47 Chalcanthite __ __ ____________________ 47 Occurrence of the ores__________________._______ 47 General statement.________________________ 47 Copper sulphide deposits in greenstone and limestone___ 48 Native copper associated with the greenstone________ 50 Placer copper__ _______ _______________ 50 Source and character of the copper deposits_____________ 50 Description of properties -__________,_____________ 54 Kotsina River basin__ ______ _____ ______ 54 Kotsina River__________________________ 54 Ames Creek.___________________________ 55 Rock Creek___ _____________,________ 55 Roaring Creek _ _ _____________ 56 Peacock Creek ____ 57 Rose claim.___________________ 57 White Dog and Mint claims______________ 58 Mountain claim________________'. _____ 58 Shower Gulch- - _ 58 Surprise Creek _ _______ 59 Laddie claim._______________________ 60 Sheehan claim_^___ _ 60 Hubbard claini 1____________________ 60 Klnvesna Creek 60 Copper Creek 62 Elliott Creek._____________________ _ 63 General description.________:__________ 63 Copper King and Mineral King claims________ 65 Claim at the head of Queen Creek__________ 66 Van Dyke claim___.,__________ 66 Copper Queen claim___ 66 Marmot claim __ 66 Louise claim 67 CONTENTS. 5 Economic geology Continued. Copper Continued. Description of properties Continued. Kotsina River basin Continued. Elliott Creek Continued. P»«<V Lizzie G claim_____ _____________ 67 Goodyear and Henry Prather claims__________ (57 Elizabeth, claim_____________________ 69 Marie Antoinette claim_________________ 70 Albert Johnson claim______________.__._ 70 Guthrie claim.___________________ ___ 70 Lei and and Lawton-claims________________ 71 Cliff claim._______________________._'_ 71 Chance claim__________________________ 71 Kuskulana River basin_____________________- __ 71 General description.-._____ ______ ____ 71 Nuggett Creek______________________ _____ 72 General outline. - 72 Valdess claim ____________________________ 7!:! One Girl claim ___ _ _________ 73 Strelna Creek ___ 74 Lakina River.____ ' ________'____^ 74 Kenuicott River basin____________________ 77 Hidden Creek_____________.._______ L _ 77 Glacier and Fourth of July creeks___________ 79 Nebraska claiui-_ __ _______________ 79 Bekka and Eli claims_________________ 79 Bonanza Creek __________________:_____ 80 Jumbo Creek_________________________ 86 Erie and Independence claims________ _ __ 87 Nikolai Creek _________________________ 88 Chit-stone River basin______________________ 89 Main stream _________________________ 89 Glacier Creek _________________________ 91 Dan Creek _______________.______________ 92 Gold______________________________________ 92 The Nizina placers ___________________________ 92 Location and history_ ____________________ 92 Geological sketch_________________________ 98 Chititu Creek ___________________________ 95 Dan Creek ___________________________ 97' Realgar __________________,__________________ 99 Coal ______________________________________ 100 Index ________________________________________ 101 ILLUSTRATIONS. Page. PLATE I. Topographic reconnaissance map of Chitina River and Copper River region, Alaska.________________________ In pocket. II. Geologic reconnaissance map and sections of the Chitiua copper belt, Alaska___________________________ In pocket. III. A, Contact of Nikolai greenstone and Chitistone limestone west of Nizina River, near Nikolai mine; B, Sheared greenstone on south side of Kotsina River below Surprise Creek_____ 24 IV. A, Thin-bedded Triassic limestone and shale on west branch of Rock Creek; B, Crumpling in thin-bedded Triassic limestone on ridge east of Gilahina River_____________ ____ V. Head of Nikolai Creek________________________ VI. A, Intrusions of fine-grained porphyry in black shale on Young Creek; B, Castle Mountain_____________________ 34 VII. A, Pleistocene gravel bluffs along north bank of Chitina River; B, Chitistone limestone on the. north side of Elliott Creek__ 38 VIII. View of Bonanza mine from Horseshoe trail--___________ 80 IX. A, View of the Nikolai vein and shaft; B, View along the vein of the Henry Prather claim____________________ 88 X. A, Contact of. the Chitistone limestone and Nikolai greenstone formations on east side of Nizina River; B, View across Nizina River into Dan Creek__________________ 92 FIGURE 1. Comparative grades of the four proposed railroad routes from the coast to the interior Copper River basin_________ 16 2. Sketch map of part, of Elliott Creek_______________ 64 3. Cl'OSS section of the Elliott Creek anticline_____'._________ 65 4. Diagram showing the relation of the faulted portions of the Goodyear claim, Elliott Creek_________________ 68 5. Sketch map of the Bonanza mine_ ___ _ _ 81 6. Form of ore body exposed in the main or northern tunnel at the Bonanza mine___________________________ 84 7. Form of ore body exposed in the southern tunnel at the Bonanza mine___________________________ 85 8. Ore body at the Jumbo claim_______:___________ 87 9. Sketch map of a part of Chititu Creek_____________ 96 6 . PREFACE. By ALFRED H. BROOKS. Native copper from the district described in this volume is the first mineral reported from Alaska. Steller, the naturalist who accompanied Bering on his voyage of discovery in 1741, noted the use of copper knives among the natives of Kayak Island. This copper undoubtedly came from the Chitina-Kotsina belt. Among the Alaskan natives the use of copper was widespread, for it was the only metal utilized by them, but apparently the century of occupation by the -Russians passed without any search on their part for the locality from which the supply was derived. The only attempt made by the Russians to explore the Copper River (Serebranikof, 1847) resulted in the massacre of the whole party by the Indians. The first successful explorations were made by Alien (1885) and by Schwatka and Hayes (1891), and the first systematic surveys were carried out by Schrader of the United States Geological Survey and his associates in 1900. It is part of the Survey's plan for the investigation of the mineral resources of Alaska to keep the work abreast of the mining develop ments in each district so far as the means available will permit. As a great deal of prospecting, which has developed many new facts in regard to the occurrence