Unnamed (near Yellow Hill)

Occurrences, Undetermined

Commodities and mineralogy

Main commodities Cr
Ore minerals chromite; magnetite

Geographic location

Quadrangle map, 1:250,000-scale KC
Quadrangle map, 1:63,360-scale A-5
Latitude 55.096
Longitude -131.565
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site represents six occurrences in about a square-mile area south and east of Yellow Hill. The occurrences are in sections 16, 17, 20, and 21, T. 78 S., R. 92 E., of the Copper River Meridian. The map site is at the approximate center of this area. The site corresponds to loc. 50a-f in Karl (1992). The location is accurate within about 0.1 mile.

Geologic setting

Geologic description

The country rocks in the area of this site are serpentinized dunite and subordinate clinopyroxenite, probably of Cretaceous age (Berg, 1972 [I 684]; Berg and others, 1988). The occurrences consist of serpentinized dunite containing disseminated magnetite and chromite, and stringers of chromite. The disseminated metalliferous minerals constitute about 3 percent of the dunite. Samples of the dunite contained up to 1000 ppm Ni, 200 ppm Co, and more than 5000 ppm Cr (Karl, 1992, loc. 50a-f).
Geologic map unit (-131.566677613944, 55.0956578201874)
Mineral deposit model Alaskan PGE (Cox and Singer, 1986; model 9).
Mineral deposit model number 9
Age of mineralization Probably Cretaceous.
Alteration of deposit Serpentinization of dunite hostrock.

Production and reserves

Workings or exploration Samples of chromite- and magnetite-bearing dunite contained up to 1000 ppm Ni, 200 ppm Co, and more than 5000 ppm Cr (Karl, 1992, loc. 50a-f).
Indication of production None

References