Unnamed Prospect (ARDF - ID010; head of Beaver Creek), Iditarod District, Yukon-Koyukuk Borough, Alaska, USA

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Location: This prospect is on a steep, north-northwest trending ridge that separates the head of Beaver Creek to the east from Windy Creek to the west. The prospect is at an elevation of about 3,200 feet, about 0.3 mile southeast of peak 3544, in the SW1/4 SE1/4 section 4, T. 32 N., R. 41 W., of the Seward Meridian. The location is accurate.
Geology: This prospect consists of chalcopyrite and pyrite in a tourmaline-quartz breccia near a N20E, steeply dipping, high-angle fault (Bundtzen and Laird, 1982). The size of the mineralized structure is not known. One grab sample from the breccia contained 2.00 percent copper, 110 parts per million (ppm) silver, 700 parts per billion (ppb) gold, and 300 ppm tungsten (Bundtzen and Laird, 1982; Miller, Bundtzen, and Gray, 2005). Grab samples of sulfide-quartz breccia collected by Battle Mountain Mining Company contained up to 10.7 parts per million gold, more than 50 ppm silver, 2,879 ppm copper, 983 ppm lead, 381 ppm arsenic, 4.2 ppm mercury, and 90 ppm tin (Szumigala, 1993).
Workings: The area was mapped and sampled by the U.S. Geological Survey and the Alaska Division of Geological and Geophysical Surveys in the late 1970s and in the 1980s. The area was studied by Anaconda Minerals Company in 1980 and 1981 (D. Obolewicz, written communication, 1981), and by Battle Mountain Mining Company in 1990 (Szumigala, 1993).
Age: Undated; may be related to emplacement of the Beaver Mountains stock which has been dated at 70.3 Ma (Bundtzen and Laird, 1982).
Alteration: Greisen developed with tourmaline, quartz, and white mica.

Commodities (Major) - Ag, Au, Cu; (Minor) - As, Hg, Pb, Sn, W
Development Status: None
Deposit Model: Sn-polymetallic veins (Cox and Singer, 1986; model 20b).

References

Bundtzen, T.K., and Laird, G.M., 1982, Geologic map of the Iditarod D-2 and eastern D-3 quadrangles, Alaska: Alaska Division of Geological and Geophysical Surveys Geologic Report 72, 1 sheet, scale 1:63,360. McGimsey, R.G., Miller, M.L., and Arbogast, B.F., 1988, Paper version of analytical results, and sample locality map for rock samples from the Iditarod quadrangle, Alaska: U.S. Geological Survey Open-File Report 88-421-A, 110 p., 1 sheet, scale 1:250,000. Miller, M.L., and Bundtzen, T.K., 1994, Generalized geologic map of the Iditarod quadrangle, Alaska showing potassium-argon, major oxide, trace element, fossil, paleocurrent, and archeological sample localities: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-A, 48 pages; 1 sheet, scale 1:250,000. Miller, M.L., Bundtzen, T.K., and Gray, J.E., 2005, Mineral resource assessment of the Iditarod quadrangle, west-central Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-B, scale 1:250,000, pamphlet. Szumigala, D.J., 1993, Gold mineralization related to Cretaceous-Tertiary magmatism in the Kuskokwim Mountains of west-central and southwestern Alaska: Los Angeles, University of California Ph.D. dissertation, 300 p.

Mineral List

Chalcopyrite Muscovite var: Sericite

Pyrite Quartz

'Tourmaline'

5 entries listed. 3 valid minerals.