Unnamed Occurrence (ARDF - LC002), Aniak District, Bethel Borough, Alaska, USA

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Site is in Lake Clark National Park and Preserve.
Location: About 3 km northwest of Telaquana Pass, on a mountain peak surrounded by glaciers. Locality 38 of MacKevett and Holloway (1977). Sec. 15, T. 10 N., R. 24 W., of the Seward Meridian. Location accurate within 1.6 km.
Geology: Skarn deposit; marble interbedded with schist, phyllite, and metamorphosed mafic volcanic rocks in a large roof pendant in granitic rocks (Nelson and others, 1983). Mineralization consists of pyrite, pyrhhotite and minor amounts of chalcopyrite and sphalerite in granitic rocks and in metasedimentary roof pendants (MacKevett and Holloway, 1977). Quite similar to the nearby Glacier Fork occurrence (ARDF number LC008) and another unnamed occurrence (ARDF number LC010). According to Nelson and others (1983, unit MzPzm), some of the metasedimentary rocks may correlate with the Kakhonak Complex of Permian (?), Triassic, and Jurassic age in the Iliamna quadrangle, and some may be graywacke of Jurassic and Cretaceous (?) age that has been metamorphosed by nearby plutonic rocks. Some of the metamorphosed volcanic rocks, especially in roof pendants, are probably part of the volcanic rocks of Tertiary age (Tv). Nelson and others (1983, unit Ti16) describe the granitic rocks as medium-grey, medium-grained biotite-hornblende granodiorite. Potassium-argon dates on biotite and hornblende from one speciman of this unit yielded ages of about 31 to 35 m.y. (Reed and Lanphere,1972; 1973).
Workings: Unknown
Age: The granodiorite that produced the skarn has potassium-argon dates on biotite and hornblende of about 31 to 35 m.y. (Reed and Lanphere,1972; 1973).
Alteration: Unknown
Production: No production
Reserves: No reserves

Commodities (Major) - Cu; (Minor) - Ag, Zn
Development Status: None
Deposit Model: Porphyry Cu or Cu skarn (Cox and Singer, 1986; model 17 or 18b)

References

Cobb, E.H., and Reed, B.L., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska; Supplement to Open-File Report 76-485; Part A, Summaries to January 1, 1981: U.S. Geological Survey Open-File Report 81-1343-A, 25 p. Cobb, E.H., and Reed, B.L., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska; Supplement to Open-File Report 76-485; Part B, Lists of references to Januray 1, 1981: U.S. Geological Survey Open-File Report 81-1343-B, 20 p. MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous mineral deposits in the western part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-F, 38 p., 1 sheet, scale 1:1,000,000. Nelson, W.H., Carlson, C., and Case, J.E., 1983, Geologic map of the Lake Clark quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1114-A, 1 sheet, scale 1:250,000. Reed, B.L., and Lanphere, M.A., 1972, Generalized geologic map of the Alaska-Aleutian range batholith showing potassium-argon ages of the plutonic rocks: U.S. Geological Survey Miscellaneous Field Studies Map MF-372, 2 sheets, scale 1:1,000,000. Reed, B.L., and Lanphere, M.A., 1973, Alaska-Aleutian Range batholith: Geochronology, chemistry, and relation to circum-Pacific plutonism: Geological Society of America Bulletin, v. 84, no. 8, p. 2583-2609.

Mineral List

Chalcopyrite

Pyrite

Sphalerite

3 entries listed. 3 valid minerals.