STUDIES RELATED TO WILDERNESS WILDERNESS AREAS Geology and Mineral Resources of the North Absaroka Wilderness and Vicinity, Park County, Wyon1ing By WILLIS H. NELSON and HAROLD J. PROSTKA, U.S. GEOLOGICAL SURVEY , and FRANK E. WILLIAMS, U.S. BUREAU OF MINES With sections on MINERALIZATION OF THE SUNLIGHT MINING REGION and GEOLOGY AND MINERALIZATION OF THE COOKE CITY MINING DISTRICT By JAMES E. ELLIOTT, U.S. GEOLOGICAL SURVEY And a section on AEROMAGNETIC SURVEY By DONALD L. PETERSON, U.S. GEOLOGICAL SURVEY STUDIES RELATED TO WILDERNESS - WILDERNESS AREAS GEOLOGICAL SURVEY BULLETIN 1447 An evaluation of the mineral potential of the area UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1980 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard, Director Library of Congress Cataloging in Publication Data Nelson, Willis Howard, 1920- Geology and mineral resources of the North Absaroka Wilderness and vicinity, Park County, Wyoming. (Studies related to wilderness-wilderness areas) (Geological Survey Bulletin 1447) Bibliography: p. 99 Supt. of Doc. no.: I 19.3:1447 1. Geology-Wyoming-Park Co. 2. Mines and mineral resources - Wyoming-Park Co. I. Prostka, Harold J., joint author. II. Williams, Frank E., joint author. Ill. Title. IV. Series. V. Series: United States Geological Survey Bulletin 1447 QE75.B9 no. 1447 [ QE182.P3) 557.3'08s [557.87'42) 77-608170 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-03271-6 STUDIES RELATED TO WILDERNESS WILDERNESS AREAS Under the Wilderness Act (Public Law 88-577, Sept. 3, 1964) cer­ tain areas within the National forests previously classified as "wilder­ ness," "wild," or "canoe" were incorporated into the National Wilderness Preservation System as wilderness areas. The act pro­ vides that the Geological Survey and the Bureau of Mines survey these wilderness areas to determine the mineral values, if any, that may be present. The act also directs that results of such surveys are to be made available to the public and submitted to the President and Congress. This bulletin reports the results of a mineral survey of the North Absaroka Wilderness, Park County, Wyoming, and some adjoining national forest lands that may be considered for wilder­ ness designation. CONTENTS Page Summary ............................................................. 1 Introduction. 2 Acknowledgments . 2 Previous studies . 6 Present investigations. 6 Geology, by Willis H. Nelson and Harold]. Prostka, U.S. Geological Survey. 7 Precambrian rocks. 8 Paleozoic and Mesozoic rocks . 8 Cenozoic rocks . 10 Willwood Formation ............................................. 10 Absaroka Volcanic Supergroup and related intrusive rocks ................. 10 Washburn Group ............................................ 12 Cathedral Cliffs Formation .................................. 14 Lamar River Formation .................................... 16 Sunlight Group .............................................. 18 Wapiti Formation ........................................ 18 Trout Peak Trachyandesite ................................. 21 Thorofare Creek Group ........................................ 23 Langford Formation ...................................... 23 Related intrusive rocks ........................................ 24 Metamorphism and alteration ...................................... 25 Quaternary units .................................................... 26 Volcanic rocks .................................................. 26 Surficial deposits ................................................ 26 Structure and geologic history .......................................... 27 Aeromagnetic survey, by Donald L. Peterson, U. S. Geological Survey ................ 32 Metallic mineral deposits, by Frank E. Williams, U.S. Bureau of Mines ............... 33 Sunlight mining region ............................................... 34 History ........................................................ 34 Winona claims and prospects ....................................... 36 Copper Lakes prospects ........................................... 41 Copper Creek adit ............................................... 42 Galena Creek basin prospects ....................................... 44 Novelty claim ................................................... 45 Morning Star claim .............................................. 45 Evening Star claim ............................................... 47 Painter mine ................................................... 49 Newton prospect ................................................ 51 Upper Silvertip Basin prospect ...................................... 51 Lee City prospect ................................................ 51 Mineralization of the Sunlight mining region, by James E. Elliott, U. S. Geological Survey .......................................... 51 v VI CONTENTS Metallic mineral deposits-Continued Page Cooke City mining district . 54 History, by Frank E. Williams, U. S. Bureau of Mines ..................... 54 Republic mine . 55 Irma mine . 55 Martin claim . 56 Mohawk-Warrior mine. 56 Woody Creek adit. ............................................... 56 Geology and mineralization of the Cooke City mining district, by James E. Elliott, U. S. Geological Survey ........................... 57 Geochemical samples and analyses . 58 Mineral potential . 59 Copper ........................................................... 59 Silver and gold. 94 Molybdenum. 94 Lead ............................................................. 95 Zinc ............................................................. 95 Chromium . 96 Uranium .......................................................... 96 Barium ........................................................... 96 Tungsten. 96 Petroleum . 97 Coal ............................................................. 97 Bentonite . 97 Sulfur ............................................................ 98 Geothermal energy . 98 Conclusions . 98 References cited . 99 ILLUSTRATIONS Page PLATE 1. Geologic map of the North Absaroka Wilderness and vicinity, Park County, Wyoming ............................................ In pocket 2. Map showing aeromagnetic datd. sample localities, and altered areas, North Absaroka Wilderness, Park County, Wyoming ............ In pocket FIGURE 1. Index map of the North Absaroka Wilderness and vicinity. 3 2-12. Photographs: 2. Pilot Peak and Index Peak. 4 3. Rock glacier on north side of Hurricane Mesa . 4 4. Big Creek Falls . 5 5. Chaotic vent-facies deposits in Wapiti Formation, head of One Hunt Creek . 11 6. Alluvial-facies deposits in Wapiti Formation, head of Timber Creek ......................................... 12 7. Volcanic sediments of Cathedral Cliffs Formation, Fox Creek. 13 8. Autobrecciated intrusive andesite . 15 9. Allochthonous Lamar River Formation overlain by Wapiti Formation and Trout Peak Trachyandesite, Pilot Peak. 17 10. View of southeastern part of wilderness showing Willwood and Wapiti Formations and Trout Peak Trachyandesite.. 19 CONTENTS VII Page FIGURE 11. Intraformational unconformity in Trout Peak Trachyandesite, The Wall ............................................ 21 12. Langford Formation and Trout Peak Trachyandesite . 24 13. Diagrammatic map and cross section of Heart Mountain fault . 28 14-21. Maps, Sunlight mining region: 14. Claim locations. 37 15. Main Winona adit, Greenhorn claim, Sulphur Creek basin . 39 16. Copper King adit, Winona group, Sulphur Creek basin ............ 40 17. Mine working south of cabin, upper Copper Creek. 43 18. Novelty adit, Galena basin ................................. 46 19. MorningStar adit, Hughes Basin ............................. 47 20. Evening Star workings, Hughes Basin ......................... 48 21. Painter mine, Silvertip Basin. 50 22. Partial claim map, Cooke City (New World) mining district . 54 TABLES Page TABLE 1. Paleozoic and Mesozoic rocks in and near the North Absaroka Wilderness 9 2. Numbers of claims filed in recorders' offices, Sunlight mining region, by decades . 35 3. Assays from the Sunlight mining region. 35 4. Analyses of stream-sediment samples from the North Absaroka Wilderness . 60 5. Analyses of bedrock samples from the North Absaroka Wilderness ......... 76 6. Semiquantitative spectrographic analyses of bedrock samples from the Sunlight mining region . 90 STUDIES RELATED TO WILDERNESS-WILDERNESS AREAS GEOLOGY AND MINERAL RESOURCES OF THE NORTH ABSAROKA WILDERNESS, PARK COUNTY, WYOMING By WILLIS H. NELSON and HAROLD j. PROSTKA, U. S. Geological Survey, and FRANK E. WILLIAMS, U.S. Bureau of Mines SUMMARY 2 The North Absaroka Wilderness is approximately 560 square miles (I ,450 km ) of rugged scenic mountainous terrain that adjoins the eastern boundary of Yellowstone National Park in northwestern Wyoming. The area was studied during 1970, 1971, and 1972 by personnel of the U. S. Geological Survey and the U. S. Bureau of Mines to evaluate its mineral-resource poten­ tial as required by the Wilderness Act of 1964. This evaluation is based on a search of the litera­ ture, courthouse and production records, geologic field mapping, field inspection of claims and prospects, analyses of bedrock and stream-sediment samples, and an aeromagnetic survey. The North Absaroka Wilderness is underlain almost entirely by andesitic and basaltic vol­ canic rocks of Eocene age. These volcanics rest on deformed sedimentary rocks of Paleozoic and, locally, of Mesozoic