Unnamed (moraine on Fairweather Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu; Ni
Other commodities Au; Ag; Co; Cr; Fe; PGE; Ti; V
Ore minerals chalcopyrite; cubanite; ilmenite; magnetite; pentlandite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale MF
Quadrangle map, 1:63,360-scale D-5
Latitude 58.873
Longitude -137.489
Nearby scientific data Find additional scientific data near this location
Location and accuracy Glacial moraine on a north arm of Fairweather Glacier, about 2.6 miles south-southeast of Mt. Fairweather contains sulfide- and oxide-rich mineral bearing detritus derived from the Mt. Fairweather. The metalliferous detritus is at about 6500-foot elevation and probably is derived from outcrops 0.2-0.4 mile to the west. The location is accurate within 0.25 miles.

Geologic setting

Geologic description

Cobbles of mafic rocks containing concentrations of magnetite-ilmenite or of disseminated sulfides, including chalcopyrite and pentlandite, occur in moraine adjacent to the Mt. Fairweather layered mafic intrusion and must have been derived from mineral deposits within the intrusion.
Plafker and MacKevett (1970) found as much as 0.5 percent copper, also 0.5 percent nickel in the first sampling of the moraine occurrence. Kimball and others (1978) found as much as 0.64 percent copper and 0.2 percent nickel in samples collected from the moraine. Gold, platinum or palladium, cobalt, and chromium were also reported in assays from samples from the moraine.
Geologic map unit (-137.490891769469, 58.8726273934143)
Mineral deposit model Unconsolidated glacial moraine containing metalliferous detritus.
Age of mineralization Recent morainal accumulation of sulfide- and heavy metallic oxide-bearing detritus derived from the Mt. Fairweather intrusion.

Production and reserves

Workings or exploration The mineralized rocks were collected from the moraine. No examination of the probable source area of the detritus was possible because of the extremely rugged terrane. Further investigations would call for trained mountaineers. The sites near Mt. Fairweather were first visited by Plafker and MacKevett (1970), who obtained materials estimated to contain as much as 0.5 percent each of copper and nickel. The sites were then resampled by the U.S. Bureau of Mines (Kimball and others, 1978, p. C108-C119). Samples 7K064 and 065 collected by the Bureau contained 0.03-0.05 ounce/ton gold, trace to 0.008 ounce/ton platinum or palladium, as much as 0.64 percent copper, 0.2 percent nickel, 200-300 ppm cobalt, and 2000-5000 ppm chromium.
Indication of production None

Additional comments

The site is in Glacier Bay National Park and Preserve. A search for the source of the metalliferous boulders would need mountaineering support.

References