Okok River

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals chalcopyrite
Gangue minerals ilmenite; magnetite; pyrite

Geographic location

Quadrangle map, 1:250,000-scale SL
Quadrangle map, 1:63,360-scale C-5
Latitude 63.37
Longitude -171.4
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Okok River flows southeast to its mouth on the southwest coast of St. Lawrence Island (about 1 mile west of Singikpak Point). The site, located within 1/2 mile, is on the west side of the river valley about 2 1/2 miles upstream of the mouth. It is locality 10 of Cobb (1972) and Cobb (1980) summarized relevant references under the name 'Okok R.'.

Geologic setting

Geologic description

Bedrock in the lower Okok River valley is a Triassic to Permian age assemblage characterized by gabbro and diabase intrusions (Patton and Csejtey, 1980). Gabbro samples from this assemblage along the Okok River contain disseminated chalcopyrite, ilmenite, magnetite, and pyrite. Two grab samples of this gabbro contain 700 ppm copper (Patton and Csejtey, 1971, P. C8). Stream sediments in the upper Okok River drainage do not have anomalous metal contents (Patton and Csejtey, 1972).
Geologic map unit (-171.402761383393, 63.3690752016795)
Mineral deposit model Disseminated sulfide minerals in gabbro.
Age of mineralization Disseminated sulfide minerals in gabbro of the Okok River drainage would be Permian in age, based on the results of two K/Ar age determinations for this assemblage (221 +/- 7 and 244 +/- 7 Ma; Patton and Csejtey, 1980).
Alteration of deposit The gabbro is apparently unaltered.

Production and reserves

Workings or exploration Two grab samples of gabbro contain 700 ppm copper (Patton and Csejtey, 1971, P. C8). Stream sediments in the upper Okok River drainage do not have anomalous metal contents (Patton and Csejtey, 1972).
Indication of production None

References