Mineral Resources of the Minarets Wilderness and Adjacent Areas, Madera and Mono Counties, California
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STUDIES RELATED TO WILDERNESS WILDERNESS AREAS Mineral Resources of the Minarets Wilderness and Adjacent Areas, Madera and Mono Counties, California By U.S. GEOLOGICAL SURVEY and U.S. BUREAU OF MINES A. Regional Setting, Geology, and Geechemical Studies of the Minarets Wilderness and Adjacent Areas, Madera and Mono Counties, California By N. KING HUBER, U.S. GEOLOGICAL SuRVEY B. Geophysical Studies of the Minarets Wilderness and Adjacent Areas, Madera and Mono Counties, California By HOWARD W. OLIVER, U.S. GEOLOGICAL SuRVEY C. Geothermal-Resource Evaluation of the Minarets Wilderness and Adjacent Areas, Madera and Mono Counties, California By ROY A. BAILEY, U.S. GEOLOGICAL SuRVEY D. Economic-Mineral Appraisal of the Minarets Wilderness and Adjacent Areas, Madera and Mono Counties, California By HORACE K. THURBER, MICHAEL S. _MILLER, C. THOMAS HILLMAN, DAVIDS. LINDSEY, and RICHARD W. MORRIS, U.S. BUREAU OF MINES STUDIES RELATED TO WILDERNESS - WILDERNESS AREAS GEOLOGICAL SURVEY BULLETIN 1516-A-D An evaluation of the mineral potential of the area UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1982 • UNITED STATES DEPARTMENT OF THE INTERIOR JAMES G. WATT, Secretary GEOLOGICAL SURVEY Dallas L. Peck, Director Library of Congress Cataloging in Publication Data Mineral resources of the Minarets Wilderness and adjacent areas, Madera and Mono Counties, California. (Geological Survey bulletin ; 1516-A-D) Bibliography: p. 154-160 Supt. of Docs. no.: I 19.3:1516-A-D 1. Mines and mineral resources--California. I. United States. Geological Survey. II. United States. Bureau of Mines. ! III. Series: United States. Geological Survey. Bulletin 1516-A-D. QE75.B9 no. 1516-A-D 557.3s 81-607191 [TN24.C2J [553'09794'48] AACR2 For sale by the Superintendent of Documents, U. S. Government Printing Office Washington, D. C. 20402 • STUDIES RELATED TO WILDERNESS WILDERNESS AREAS In accordance with the provisions of the Wilderness Act (Public Law 88-577, September 3, 1964) and the Joint Con ference Report on Senate Bill 4, 88th Congress, the U.S. Geological Survey and U.S. Bureau of Mines have been conducting mineral surveys of wilderness and primitive areas. Studies and reports of all primitive areas have been completed. Areas officially designated as "wilderness," "wild," or "canoe" when the Act was passed were incor porated into the National Wilderness Preservation System, and some of them have been studied and others are presently being studied. The Act provided that areas under consider-' ation for wilderness designation should be studied for suit ability for incorporation into the Wilderness System. The mineral surveys constitute one aspect of the suitability studies. This report discusses the results of a mineral survey of the Minarets Wilderness, California, and adjacent areas th.at are being considered for wilderness designation . • CONTENTS • [Letters designate chapters] Page Summary.............................................................................................................................................................................. 1 (A) Regional setting, geology, and geochemical studies of the Minarets Wilderness and adjacent areas, Madera and Mono Counties, California, by N. King Huber, U.S. Geological Survey................................................ 5 (B) Geophysical studies of the Minarets Wilderness and adjacent areas, Madera and Mono Counties, California, by Howard W. Oliver, U.S. Geological Survey............................................................................................................................ 49 (C) Geothermal-resource evaluation of the Minarets Wilderness and adjacent areas, Madera and Mono Counties, California, by Roy A. Bailey, U.S. Geological Survey.......................................................................................................... 73 (D) Economic-mineral appraisal of the Minarets Wilderness and adjacent areas, Madera and Mono Counties, California, by Horace K. Thurber, MichaelS. Miller, C. Thomas Hillman, DavidS. Lindsey, and Richard W. Morris, U.S. Bureau of Mines .............................................................................. 91 Combined list of references ································································································-~·-······························ 154 ILLUSTRATIONS Page PLATE 1. Generalized geologic map of the Minarets Wilderness and adjacent areas, California .................................................................................... .In pocket 2. Map showing sample localities in the Minarets Wilderness and adjacent areas, California .................................................................................. .In pocket 3. Generalized magnetic-intensity map of the Minarets Wilderness and adjacent areas, California ............................................. ....... .In pocket FIGURE 1. Map of the Minarets Wilderness and adjacent areas, California .......... 2 • v ,, \ Any use of trade names or trademarks in this publication is for descriptive purposes only and does not constitute endorsement by the U.S. Geological Survey. STUDIES RELATED TO WILDERNESS • MINERAL RESOURCES OF THE MINARETS WILDERNESS AND ADJACENT AREAS, MADERA AND MONO COUNTIES, CALIFORNIA By U.S. GEOLOGICAL SURVEY and U.S. BUREAU OF MINES SUMMARY A mineral survey of the Minarets Wilderness and adjacent areas in the central Sierra Nevada, Calif., was conducted during 1973, 1974, and 1975. The total area covers about 240 mi2 (620 km2) in Sierra and lnyo National Forests, of which about 170 mi2 (440 km2) is within the officially designated Minarets Wilderness. The mineral-resource potential was evaluated by geological, geochemical, and geophysical studies by the U.S. Geological Survey, and by examination of mineral ized rocks, prospects, and mining claims by the U.S. Bureau of Mines. The results of the survey indicate that the study area has small to moderate submarginal to paramarginal resources of copper, silver, zinc, lead, iron, and tungsten and an unevaluated potential for molybdenum resources. Limestone is present, but not of commercial quantity or quality. No other industrial minerals have been recognized in quantity. Granitic rocks have potential use as decorative stone, and sand and gravel could be produced from either alluvial deposits or glacial drift; however, these commodities are more accessible elsewhere at localities closer to markets. The study area has no potential for fossil fuels, and, because of the general geologic environment, the potential for nuclear fuel minerals is considered to be low. The study area has low geothermal potential, even though it is on the west edge of the Mono-Long Valley Known Geothermal Resource Area. The area is underlain by metavolcanic and metasedimentary rocks that have been intruded by granitic rocks of the Sierra Nevada batholith. Pliocene and Pleistocene volcanic rocks are present locally. With few exceptions, the known occurrences of mineralized rock are confined to the metamorphic rocks,and the exceptions appear to be confined to plutonic rocks that are older than the Late Cretaceous granitic rocks which make up the bulk of the batholithic rocks in the study area. Although no mineral production has been recorded from prospects within the study area, mines adjacent to it have produced significant amounts of gold and tungsten. Production figures are incomplete, but mines in the Mammoth mining district (fig. 1) may have produced as much as $1 million worth of gold, silver, and other metals at then-current prices. The Monte Cristo mine adjacent to the old Mammoth Mine in the Mammoth district was in production during 1978. 1 2 MINARETS AND ADJACENT AREAS, CALIFORNIA The Strawberry mine, adjacent to the south boundary of the study area, produced over 40,000 short ton units (363,000 kg) of tungsten t~ioxide (W03) from high-grade ore, and additional unrecorded production is believed to have corp.e from the mine. In 1977 preparations were being made by a major company to resume tungsten production from the Strawberry mine. Approximately 1,200 mining claims have been located in the Minarets study area since the 1890's, of which about 25 were being held during the time of investigation. Nine claims have been patented. • EXPLANATION 1. Mono Pass prospects 2. Bliss prospect 3. Crown Point-Nidever prospect 4. Red Top Mountain prospects 5. Minarets magnetite prospect 6. Mark prospect Paved road Secondary road Trail )( Prospect Mammoth 'Jt mine Devils Postpile National Monument Study-area boundary 0 4 8 KILOMETERS 1 1 I 1 I I I 1 0 1 2 3 4 MILES FIGURE 1.-Minarets Wilderness and adjacent areas, California, showing areas of greatest mineral-resource potential. SUMMARY 3 The Crown Point-Nidever prospect on Shadow Creek (fig. 1, No. 3) has about 9 million tons (8 million t) of submarginal resources of zinc, silver, copper, and lead in tactite. Additional resources are in southeasterly extensions of the tactite in the Nelson adit area and on the Mike No. 2 claim, but no resource estimate could be made because the deposits are too poorly exposed. An iron-bearing lens on the Minarets magnetite prospect (fig.1, No.5) west oflron Mountain contains about 8.5 million tons (7.7 million t) of submarginal iron • resources. Other smaller magnetite masses are in the vicinity but are widely scattered and thus preclude resource estimates. North-south-trending gash fracture veins in metavolcanic rocks on the Mark prospect (fig. 1, No.6), in the southern part of the area, contain at least