Big Horn

Prospect, Inactive

Alternative names

Finch

Commodities and mineralogy

Main commodities Cu
Ore minerals bornite; chalcocite; malachite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MC
Quadrangle map, 1:63,360-scale C-7
Latitude 61.6565
Longitude -143.5958
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is on the north valley wall of Kuskulana Glacier. It is at an elevation of about 4,500 feet, 5,200 feet southwest of elevation 6940, and 1,700 feet from Kuskulana Glacier. The prospect is near the northwest corner of section 33, T. 2 S., R. 10 E. of the Copper River Meridian. This is locality 157 of MacKevett (1976); the location is accurate to within about 1,000 feet. Cobb and MacKevett (1980) included this prospect under the name 'Big Horn'.

Geologic setting

Geologic description

The deposit at this prospect consists of bornite-, chalcocite-, and malachite-bearing veins and pods in strongly faulted Triassic Nikolai Greenstone (MacKevett, 1976). One disk-shaped bornite-chalcocite-quartz mass was up to 16 feet across (Moffit and Mertie, 1923; Van Alstine and Black, 1946). The deposits were explored by several short adits and numerous surface workings. 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 (-143.59788925311, 61.6560488197341)
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 several adits and surface workings.
Indication of production None

Additional comments

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

References