|Quadrangle map, 1:250,000-scale||SL|
|Quadrangle map, 1:63,360-scale||C-5|
|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 descriptionBedrock 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.|
|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|
Cobb, E.H., 1972, Metallic mineral resources map of the Saint Lawrence quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-465, 1 sheet, scale 1:250,000.
Cobb, E.H., 1980, Summaries of data and lists of references to metallic and selected nonmetallic mineral deposits in fifteen quadrangles in southwestern and west-central Alaska: U.S. Geological Survey Open-File Report 80-909, 103 p.
Patton, W.W., Jr., and Csejtey, Bela, Jr., 1971, Preliminary geologic investigations of western St. Lawrence Island, Alaska: U.S. Geological Survey Professional Paper 684-C, p. C1-C15.
Patton, W.W., Jr., and Csejtey, Bela, Jr., 1972, Analysis of stream-sediment and rock samples from St. Lawrence Island, Alaska, 1966-1971: U.S. Geological Survey Open-File Report 72-293, 78 p.
|Reporters||Travis L. Hudson (Applied Geology)|
|Last report date||9/10/1998|