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  3. Alaska Resource Data File (ARDF)

Unnamed (near head of Lakina Glacier)

Occurrence, Inactive

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Commodities and mineralogy

Main commodities Cu
Other commodities Ag; Cr
Ore minerals malachite

Geographic location

Quadrangle map, 1:250,000-scale MC
Quadrangle map, 1:63,360-scale C-7
Latitude 61.6248
Longitude -143.2948
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on the south end of a large nunatak near the head of Lakina Glacier. It is at an elevation of about 5,600 feet, 2,000 feet west-northwest of elevation 6830 and 8,000 feet southwest of elevation 8597. It is in the NE1/4 of section 7, T. 3 S., R. 12 E. of the Copper River Meridian. This is locality 119 of MacKevett (1976); the location is accurate to within about 500 feet.

Geologic setting

Geologic description

This occurrence consists of secondary copper minerals (assumed to be mostly malachite) in sheared Triassic Nikolai Greenstone (MacKevett, 1976). A sample contained 7 parts per million (ppm) silver, 500 ppm chromium, and 15,000 ppm copper. 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 (-143.296888088465, 61.6243583533231)
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 Only limited surface sampling.
Indication of production None

Additional comments

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

References

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.
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