Unnamed (west of Mt. Fairweather)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu; Ni
Other commodities Co; Cr; PGE; Ti
Ore minerals chalcopyrite; cubanite; malachite; pentlandite or nickeliferous pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale MF
Quadrangle map, 1:63,360-scale D-5
Latitude 58.9
Longitude -137.63
Nearby scientific data Find additional scientific data near this location
Location and accuracy
The occurrence is on the west contact of the Mt. Fairweather mafic intrusion about 3.7 miles bearing about 263 degrees (true azimuth) from the top of Mt. Fairweather.
The location has not been occupied, but there are conspicuous copper (malachite?) stains both in the intrusion and the country rocks in the contact zone. The mineralization may extend north along the contact, because sulfide boulders were found on Sea Otter Glacier to the north, as well as on the glacier between Sea Otter and Fairweather Glaciers.

Geologic setting

Geologic description

This occurrence, and the occurrence of detrital mineralized mafic rocks in nearby glacial moraine (MF016 and MF017), suggests that there may be (a) Brady Glacier-type nickel-copper deposits in the Mount Fairweather layered mafic-ultramafic intrusion and (b) contact-type copper deposits in the schist country rocks. The inferred mineral deposits are in or at the contact of the Mt. Fairweather layered mafic intrusion, the northern-most of four layered mafic complexes of the Fairweather Range (Brew and others, 1978). The primary copper sulfides exposed at or near the contact have locally been oxidized to malachite, forming copper-stained zones visible from aircraft fly-by. The sites have not been occupied.
Geologic map unit (-137.631877259124, 58.8996466253344)
Mineral deposit model Cumulate or sulfide segregations in layered-mafic intrusions. Contact deposits in schist. Partly oxidized.
Age of mineralization Tertiary.
Alteration of deposit Local secondary alteration of copper-bearing minerals.

Production and reserves

Workings or exploration Helicopter reconnaissance reported in Kimball and others (1978, Fig. C-34, p. C117-C118) found conspicuous copper staining near the western contact of the Mt. Fairweather intrusion. No landings were possible.
Indication of production None

Additional comments

The site is in Glacier Bay National Park and Preserve. Further exploration would need mountaineering support.

References