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Lost Cabin Extension

Prospect, Inactive

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Commodities and mineralogy

Main commodities Cu
Ore minerals bornite; chalcocite; chalcopyrite

Geographic location

Quadrangle map, 1:250,000-scale MC
Quadrangle map, 1:63,360-scale C-8
Latitude 61.7307
Longitude -143.9861
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is west of the lower Kluvesna River. It is at an elevation of about 2,400 feet near the southeast corner of section 32, T. 1 S., R 8 E. of the Copper River Meridian. This is locality 177 of MacKevett (1976) and locality 1 of MacKevett and others (1978). The location is accurate to within about 100 feet.

Geologic setting

Geologic description

The deposit at this prospect consists of chalcocite, bornite, and chalcopyrite that are sparsely disseminated in iron-stained Triassic Nikolai Greenstone near its contact with overlying Triassic Chitistone Limestone (Moffit and Mertie, 1923; MacKevett, 1976). The deposits were explored by 4 adits and several open cuts. The widespread deposition of copper in Triassic greenstone and limestone of the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).
Geologic map unit (-143.988196793224, 61.7302370510395)
Mineral deposit model Basaltic Cu (Cox and Singer, 1986; model 23)
Mineral deposit model number 23
Age of mineralization Cretaceous? The widespread deposition of copper in Triassic greenstone and limestone of the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).
Alteration of deposit Oxidation.

Production and reserves

Workings or exploration The deposits were explored by 4 adits and several open cuts.
Indication of production None

Additional comments

The locality is in the Wrangell-Saint Elias National Park and Preserve.

References

MRDS Number A011761

References

MacKevett, E.M., Jr., 1976, Mineral deposits and occurrences in the McCarthy quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-773-B, 2 sheets, scale 1:250,000.
MacKevett, E.M., Jr., Cox, D.P., Potter, R.W., III, and Silberman, M.L., 1997, Kennecott-type deposits in the Wrangell Mountains, Alaska--High-grade copper ores near a basalt-limestone contact, in Goldfarb, R.J., and Miller, L.D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 66-89.
MacKevett, E.M., Jr., Smith, J.G., Jones, D.L., and Winkler, G.R., 1978, Geologic map of the McCarthy C-8 quadrangle, Alaska: U.S. Geological Survey Geologic Quadrangle Map GQ-1418, 1 sheet, scale 1:63,360.
Moffit, F.H., and Mertie, J.B., Jr., 1923, The Kotsina-Kuskulana district, Alaska: U.S. Geological Survey Bulletin 745, 149 p.
Silberman, M.L., MacKevett, E.M., Jr., Connor, C.L., and Mathews, A., 1980, Metallogenic and tectonic significance of oxygen isotope data and whole-rock potassium-argon ages of Nikolai Greenstone, McCarthy quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-2019, 31 p.
Reporters Travis L. Hudson (Applied Geology, Inc.)
Last report date 1/12/2003