|Quadrangle map, 1:250,000-scale||SL|
|Quadrangle map, 1:63,360-scale||C-6|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Ikalooksik River flows northward to Niyrakpak Lagoon on northwest St. Lawrence Island. This site includes the drainage area of the principal course of the river where stream sediments collected over a length of 8 miles have low but consistently anomalous amounts of copper. It was not identified as a separate locality by Cobb (1972, 1980).|
Stream sediments collected along the main drainage of the Ikalooksik River, over a distance of 8 miles, have low but anomalous levels of copper, vanadium, nickel, and manganese. Of the 21 stream sediment samples along this drainage, 18 have 100 to 150 ppm copper, all have 300 to 1,000 ppm vanadium, all have 30 to 100 ppm Ni, and 20 contain 1,500 to 5,000 ppm Mn (Patton and Csejtey, 1972). Nineteen of these samples have chromium values between 100 and 300 ppm. These widespread slightly elevated metal values probably reflect a general characteristic of the bedrock in the drainage area.The bedrock in this drainage 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 (see SL012) contain disseminated chalcopyrite and up to 700 ppm copper (Patton and Csejtey, 1971, p. C15). Samples of gabbro from along the Ikalooksik River are not available but the slightly elevated metal contents in stream sediments throughout this drainage probably reflect the presence of gabbro intrusions here.
|Geologic map unit||(-171.502779915865, 63.5390755991378)|
|Mineral deposit model||Disseminated sulfide minerals in gabbro.|
|Age of mineralization||Original, disseminated sulfide minerals in gabbro would be Triassic to Permian in age based on the results of two K/Ar age determinations on associated intrusive rocks (221 +/- 7 and 244 +/- 7 Ma; Patton and Csejtey, 1980).|
|Workings or exploration||Of the 21 stream sediment samples along this drainage, 18 have 100 to 150 ppm copper, all have 300 to 1,000 ppm vanadium, all have 30 to 100 ppm Ni, and 20 contain 1,500 to 5,000 ppm Mn (Patton and Csejtey, 1972). Nineteen of these samples have chromium values between 100 and 300 ppm.|
|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|