Unnamed (head of Kuskokwim River)

Occurrences, Inactive

Commodities and mineralogy

Main commodities Au; Cu; Mo; Zn
Ore minerals arsenopyrite; chalcopyrite; pyrite; pyrrhotite; molybdenite; sphalerite
Gangue minerals ankerite; calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale LH
Quadrangle map, 1:63,360-scale B-2
Latitude 61.49
Longitude -153.4826
Nearby scientific data Find additional scientific data near this location
Location and accuracy
This occurrence is in the headwaters of the South Fork Kuskokwim River.
It is at an elevation of 4,000 feet along the south side of the river valley and 5.3 miles northeast of Snowcap Mountain. The map site is in the SE 1/4 section 12, T 16 N, R 24 W, of the Seward Meridian. This is locality 9 of Cobb (1972 [MF 412]; 1976 [OF 76-485]). The location is probably accurate to within one mile. Included with this location is a reported gold occurrence (Resource Associates of Alaska, 1976, p. 86) that is about 1 mile to the east, near peak 6425.

Geologic setting

Geologic description

Reed and Elliott (1970) reported that quartz float at this locality includes cobbles containing (1) as much as 40 percent disseminated pyrrhotite and minor chalcopyrite, (2) less than 2 percent molybdenite, and (3) 1- to 3-mm- wide veinlets with less than 10 percent sphalerite and pyrite. Samples contained as much as 12 ppm gold (Reed and Elliott, 1970; Gamble and others, 1989). Quartz veins 1 mile to the east, near peak 6425, are as much as 6 inches wide and contain arsenopyrite, pyrite, chalcopyrite, pyrrhotite, and as much as 2.3 ppm gold (Resource Associates of Alaska, 1976). These occurrences are near the contact of Tertiary diorite and quartz monzonite stocks with Cretaceous sedimentary rocks.
Geologic map unit (-153.484843819531, 61.4893569540709)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986, model 22c)
Mineral deposit model number 21c
Age of mineralization Tertiary. Quartz veins crosscut Tertiary intrusive rocks or nearby, thermally metamorphosed sedimentary rocks.
Alteration of deposit Silicification.

Production and reserves

Workings or exploration Reconnaissance sampling has been completed in this area (Reed and Elliott, 1970).
Indication of production None