Unnamed (head of South Fork Kuskokwim River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Cu
Ore minerals chalcopyrite; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale LH
Quadrangle map, 1:63,360-scale C-1
Latitude 61.5687
Longitude -153.3201
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 6,200 feet on a ridge along the east side of the southeast headwater tributary of South Fork Kuskokwim River. The map site is 0.4 mile south-southwest of peak 6980, in the northeast corner of section 17, T 17 N, R 22 W, of the Seward Meridian. This is locality Cobb (1972 [MF 412]; 1976 [OF 76-485]). The location is probably accurate to within a quarter of a mile.

Geologic setting

Geologic description

Reed and Elliott (1970) reported that sparse fractures as much as 1 cm wide in quartz monzonite are filled with quartz, chalcopyrite, pyrite, and traces of other sulfide minerals. Pyrite and chalcopyrite are also disseminated in the quartz monzonite. A sample of a vein contained greater than 20,000 ppm copper, 100 ppm silver, and anomalous lead. The mineralized quartz monzonite is Tertiary; it intrudes upper Mesozoic slate and graywacke as well as older, probably Cretaceous, granitic rocks (Cobb and Reed, 1981).
Geologic map unit (-153.32232559308, 61.5680694593986)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986, models 22c)
Mineral deposit model number 22c
Age of mineralization Tertiary. Quartz veins and mineralization crosscut Tertiary intrusive rocks.
Alteration of deposit Quartz veining.

Production and reserves

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