STUDIES RELATED TO WILDERNESS PRIMITIVE AREAS GLACIER, WYOMING GEOLOGICAL SURVEY BULLETIN 1319-F Mineral Resources of the Glacier Primitive Area, Wyoming By H. C. GRANGER, E. J. McKAY and R. E. MATTICK, U.S. GEOLOGICAL SURVEY, and by LOWELL L. PATTEN and PAUL McILROY, U.S. BUREAU OF MINES STUDIES RELATED TO WILDERNESS PRIMITIVE AREAS GEOLOGICAL SURVEY BULLETIN 1319-F An evaluation of the mineral potential of the area UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1971 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY William T. Pecora, Director Library of Congress catalog-card No. 73-609781 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 STUDIES RELATED TO WILDERNESS PRIMITIVE AREAS In accordance with the provisions of the Wilderness Act (Public Law 88-577, September 3, 1964) and the Conference Report on Senate bill 4, 88th Congress, the U.S. Geological Survey and the U.S. Bureau of Mines are making mineral surveys of wilderness and primi­ tive areas. Areas officially designated as "wilderness," "wild," or "canoe" when the act was passed were incorporated into the National Wilderness Preservation System. Areas classed as "primitive" were not included in the Wilderness System, but the act provides that each primitive area be studied for its suitability for incorporation into the Wilderness System. The mineral surveys constitute one aspect of the suitability studies. This bulletin reports the results of a mineral survey in the Glacier Primitive Area and vicinity, Wyoming. The area discussed in the report includes the primitive area, as denned, and some bordering areas that may come under discussion when the area is considered for wilderness status. CONTENTS Page Summary _______________________________ _ Fl Introduction ___________________________________ 2 Previous work __________________________~ __ 7 Acknowledgments ______________ _ 8 Geology _________________________________________ 9 Geologic setting and history _________________ _ 9 Precambrian rocks _______________________ 10 Gneissic rocks __________________ _ _ 11 Ultramafic rocks ____ __ __ ____ 14 Migmatite _______________________________ - 15 Mount Helen structural belt _____________________ 20 Granite of Middle Mountain _______________ _ 21 Porphyritic granite ___________________________ 22 Other granitic bodies _________________________ 23 Pegmatite bodies ___________________________ 24 Diabase ___________________________________ 24 Paleozoic rocks _________________________________ 27 Tertiary rocks _________________________________ 30 Quaternary deposits ______________________________ 31 Glacial deposits ____________________________ 31 Alluvium ________________________________ 32 Landslide debris ____________________________ 32 Felsenmeer _________________________________ 32 Structure ___________________________________ 33 Alteration related to faults ______________________ 38 Mineral resources _________________________________ 39 History and production _______.____________________ 39 Geochemical sampling and analytical techniques __________ 40 Results of sampling stream sediments for base metals ______- 41 Precious metals ________________________________ 44 Sulfide-mineral occurrences ________________________ 45 Gossan- and pyrite-bearing veins ___________________ 45 Disseminated sulfide-mineral occurrences _____________ 47 Magnetite-hematite veins __________________________ 47 Chromium and nickel _____________________________ 48 Nonmetallic minerals _____________________________ 49 Oil and gas _________________________________- 50 Mines and prospects ___________________________ 50 Lime Kiln Gulch _____________________________ 52 Whisky Mountain ____________________________ 53 Little Warm Spring Creek _____________________ 54 VI CONTENTS Page Mineral Resources Continued Mines and Prospects Continued Red Creek _______________________________ F55 Moon Lake _________________________________ 56 Dinwoody Creek _____________________________ 56 Union Pass _________________________________ 56 Decorative stone _____________________________ 57 Union Pass uranium claims _____________________ 57 Other prospects ______________________________ 57 Interpretation of aeromagnetic data ______________________ 57 Conclusions ______________________________________ 60 References cited _________________________________ 60 Index ________________________________________ 111 ILLUSTRATIONS [Plates are in pocket] PLATE 1. Geologic map of the Glacier Primitive Area, Wyoming. 2. Map of the Glacier Primitive Area, Wyoming, showing geochemical sample localities. Page FIGURE 1. Index map of Wyoming showing area studied ______ F2 2-16. Photographs: 2. Gannett Peak flanked by Mount Warren and Koven Peak as seen from the southern end of Downs Glacier _________ _ 3 3. Two prominent physiographic features: The For­ tress and the Brown Cliffs ___________- 4 4. Crest of the Wind River Range _________ 5 5. Broad glaciated and alluviated part of the valley of Dinwoody Creek _________________ 6 6. Part of a brecciated amphibolite block included in migmatite, showing the intricate pattern of cementation by pegmatite ____ _ ___ 13 7. Chimney Rock, a landmark along the south edge of upper Horse Ridge _______________ 15 8. Closeup of Chimney Rock from Horse Ridge __ 16 9. Migmatite showing disoriented blocks of biotite- quartz-feldspar gneiss _________ ___ 18 10. Migmatite showing the speckled hornblende phase of the porphyritic granite injected into biotite-quartz-feldspar gneiss __________ 19 11. Diabase dike ______________________ 26 12. The Paleozoic sedimentary sequence _______ 27 13. Uplifted segment of peneplain and terminal moraine ________________________ 31 14. Surfaces covered by felsenmeer __________ 33 15. The beveling effect of peneplanation on Horse Ridge __________________________ 34 CONTENTS VII Page FIGURES 2-16. Photographs Continued 16. Topographic lineament formed along the Alpine Lakes shear zone _________________ F36 17. Map showing claims and leases in and near the Glacier Primitive Area ________________________ 51 TABLES Page TABLE 1. Measured thicknesses of Paleozoic sedimentary rocks in and near the Glacier Primitive Area _____ _ F28 2. Some compositional differences in sediment-sample pairs collected from the same sample sites at different times __ 42 3. Some stream-sediment samples that contain anomalous lead or copper according to semiquantitative spectro- graphic analyses but show normal CxHM analyses _ 42 4. Crustal abundance of some metallic elements compared with their abundance in rocks of the Glacier Primitive Area _____________________ ___________ 49 5-11. Analyses of samples from the Glacier Primitive Area: 5. Sedimentary rock samples _______ - 64 6. Felsic rock samples ______________-_ _. 66 7. Mafic and ultramafic rock samples ___ . 76 8. Miscellaneous rock samples ____________ 80 9. Breccia and vein samples ____________ . 82 10. Stream-sediment and soil samples _________. 86 11. Pan-concentrated stream-sediment samples _ . 104 STUDIES RELATED TO WILDERNESS PRIMITIVE AREAS MINERAL RESOURCES OF THE GLACIER PRIMITIVE AREA, WYOMING By H. C. GRANGER, E. J. McKAY, and R. E. MATTICK, U.S. GEOLOGICAL SURVEY, and by LOWELL L. PATTEN and PAUL MC!LROY, U.S. BUREAU of MINES SUMMARY A mineral survey of the Glacier Primitive Area and an adjoining area to the northwest was made in 1968 and 1969 by the U.S. Geological Survey and the U.S. Bureau of Mines. The study area was mapped geologically, an aeromagnetic survey was made, a total of 1,076 samples (593 stream-sedi­ ment and panned-concentrate samples and 483 rock samples) was collected and analyzed, and known mineral deposits and claims were appraised from both geological and mineral-potential viewpoints. The area studied is along the northeast flank of the Wind River Range in western Wyoming and includes the Glacier Primitive Area, enclosing about 277 square miles, and an adjacent area of about 65 square miles. It contains some of the most spectacular alpine scenery in the Western United States. From the high, craggy, glacier-dominated spine of the Continental Divide, the terrain drops toward the east and north onto an intricately incised se­ ries of peneplained uplands and rounded hills. Much of the area is dotted with glacially carved lakes connected and drained by cascading mountain streams. Elevations range from 13,785 feet at the crest of Gannett Peak, the highest in Wyoming, to about 6,790 feet in the valley of Dinwoody Creek, whose source is partly in glaciers on the flanks of Gannett Peak. A large part of the area is above the tree line, but the lower elevations are partly covered with spruce, pine, grasses, and low-growing flowering plants. The study area is largely underlain by Precambrian crystalline rocks but is flanked along the northeast edge by a sequence of Paleozoic marine sedi­ mentary rocks which once also mantled the crystalline core of the Wind River Range. The north-central part of the study area is occupied by a north-trending granitic mass named the Middle Mountain batholith, which is about 5 miles wide and 25 miles long. This body grades outward into migma- tite and agmatite which, in turn, grade outward into paragneisses that form the framework of the core of the range. These rocks terminate rather ab­ ruptly on the south at a northwest-trending zone that probably represents a very old metamorphosed fault zone. South of this zone a different migmatite unit appears to border another granitic batholith whose northern parts are represented