Unnamed (head of South Fork Kuskokwim River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Cu; Mo; Sn
Ore minerals chalcopyrite; pyrite
Gangue minerals quartz; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale LH
Quadrangle map, 1:63,360-scale C-2
Latitude 61.5182
Longitude -153.4803
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 4,800 feet on the south side of a glacier that occupies the central headwater tributary of the South Fork Kuskokwim River. The map site is in the SE1/4 section 32, T 17 N, R 23 W, of the Seward Meridian. This is locality 8 of Cobb (1972 [MF 412]; 1976 [OF 76-485]) and locality 24 of Gamble and others (1989). The location is probably accurate to within a quarter of a mile.

Geologic setting

Geologic description

Reed and Elliott (1970) reported finding two sulfide-bearing boulders at this locality. The boulders are of Tertiary quartz diorite and diorite gneiss (Cobb and Reed, 1981). The quartz diorite boulder contained quartz-tourmaline veins carrying 15 percent chalcopyrite and 5 percent pyrite. The diorite gneiss boulder contained tourmaline and 15 percent disseminated chalcopyrite. Rock samples contained as much as 50 ppm silver, 700 ppm molybdenum, 700 ppm tin, and 0.7 ppm gold.
Geologic map unit (-153.482542454751, 61.5175582416358)
Mineral deposit model Polymetallic veins and porphyry Cu? (Cox and Singer, 1986, models 22c and 21a?)
Mineral deposit model number 22c and 21a?
Age of mineralization Tertiary. Quartz veins and mineralization crosscut Tertiary intrusive rocks.
Alteration of deposit Quartz-tourmaline veining and replacement(?).

Production and reserves

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