Unnamed (east of lower Gakona Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Co
Ore minerals chalcopyrite; pyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-3
Latitude 63.2199
Longitude -145.1148
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation 5,300 feet approximately 2 miles east of lower Gakona Glacier. It is in the SW1/4SW1/4 section 32, T. 19 S., R. 14 E., Fairbanks Meridian.

Geologic setting

Geologic description

The north-northeast-trending deposit at this site consists of steeply dipping east-west-trending Upper Triassic layered gabbro, peridotite, and pyroxenite (W.T. Ellis, oral communication, 1994). Some of the gabbro and pyroxenite are very coarse grained. A 3-foot-thick iron-stained zone that strikes north and dips 45E is serpentinized and contains disseminated to semimassive segregations of pyrite, pyrrhotite, and chalcopyrite. A grab sample of a sulfide-rich boulder contained 1,056 parts per million (ppm) copper and 102 ppm cobalt.
Geologic map unit (-145.117021782233, 63.2194960241499)
Mineral deposit model Ni-Cu-PGE in differentiated mafic-ultramafic sill.
Age of mineralization Late Triassic.
Alteration of deposit Conspicuous iron-staining and moderate to strong serpentinization.

Production and reserves

Workings or exploration The prospect was discovered in 1994 by American Copper and Nickel Company (W.T. Ellis, oral communication, 1994).
Indication of production None

References

Reporters W.T. Ellis (Alaska Earth Science), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS)
Last report date 8/14/2002