|Quadrangle map, 1:250,000-scale||GO|
|Quadrangle map, 1:63,360-scale||C-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is on the west side of Kemuk River, 2 miles southeast of Atshichlut Mountain. It is area 4 of Kilburn and others (1993) and also includes areas of copper-bearing mineralization noted by Hoare and Cobb (1977) along a north-trending fault west of Kemuk River (Hoare and Coonrad, 1978). The map site is at an elevation of about 1,300 feet, just east of the center of section 34, T 5 S, R 62 W, of the Seward Meridian. It is approximately located, perhaps within a mile.|
Geologic descriptionThe upland between Togiak Lake and Kemuk River is cored by a large, Cretaceous(?) granitic pluton with a well-developed hornfels aureole (Hoare and Coonrad, 1978). Many stream-sediment samples in this area contain anomalous amounts of copper and manganese (Cieutat and others, 1988; Hessin and others, 1978 [OF 78-9-M]). A large north-trending, high-angle fault transects the area just to the west of Kemuk River. Hoare and Cobb (1977) reported copper-bearing minerals in volcaniclastic rocks along this fault. Large debris fans on the west side of Kemuk River contain blocks of volcanic sandstone, bleached and iron-stained argillite, and highly silicified argillite that contain milky quartz veins, disseminated pyrite, and thin pyrite veinlets (Kilburn and others, 1992). Float samples of altered argillite contain up to 27 ppm Ag, 150 ppm As, 0.4 ppm Au, greater than 5,000 ppm Ba, 1.8 ppm Hg, 52 ppm Mo, 310 ppm Pb, and 570 ppm Zn (Kilburn and others, 1992, Table 1).
|Geologic map unit||(-159.802226723937, 59.6992485147836)|
|Mineral deposit model||Polymetallic veins (Cox and Singer, 1986; model 22c)|
|Mineral deposit model number||22c|
|Age of mineralization||Probably Late Cretaceous. Mineralization is probably related to the granitic pluton in the area, which is part of a regionally extensive Upper Cretaceous and Lower Tertiary plutonic suite. K/Ar ages for granitic samples from the nearby pluton to the east are 63.7 +/- 2 Ma on biotite and 67.5 +/-3 Ma on hornblende (Hoare and Coonrad, 1978).|
|Alteration of deposit||Silicification and oxidation.|
|Workings or exploration||Reconnaissance stream-sediment sampling has been completed in the area.|
|Indication of production||None|
|MRDS Number||A010301; DE00939|
Cieutat, B.A., Goldfarb, R.J., and Specman, W.S., 1988, Analytical results and sample locality map of stream-sediment, heavy-mineral-concentrate, and organic material samples from the Goodnews, Hagemeister Island, and Nushagak quadrangles, southwest Alaska: U.S. Geological Survey Open-File Report 88-591, 187 p., plate.
Hessin, T.D., Taufen, P.M., Seward, J.C., Quintana, S.J., Clark, A.L., Grybeck, Donald, Hoare, J.M., and Coonrad, W.L., 1978, Geochemical and generalized geological map showing distribution and abundance of copper in the Goodnews and Hagemeister quadrangles region, southwestern Alaska: U.S. Geological Survey Open-File Report 78-9-M, 2 sheets, scale 1:250,000.
Hoare, J.M., and Cobb, E.H., 1977, Mineral occurrences (other than mineral fuels and construction materials) in the Bethel, Goodnews, and Russian Mission quadrangles, Alaska: U.S. Geological Survey Open-File Report 77-156, 98 p.
Hoare, J.M., and Coonrad, W.L., 1978, Geologic map of the Goodnews and Hagemeister Island quadrangles region, southwestern Alaska: U.S. Geological Survey Open-File Report 78-9-B, 2 sheets, scale 1:250,000.
Kilburn, J., Box, S.E., Goldfarb, R.J., and Gray, J.E., 1992, Geochemically anomalous areas in the eastern Goodnews Bay 1 degre x 3 degree quadrangle, southwest Alaska, in Bradley, D.C., and Ford, A.B., eds., Geologic studies by the U.S. Geological Survey in 1990: U.S. Geological Survey Bulletin 1999, p. 156-162.
|Reporters||Travis L. Hudson|
|Last report date||3/20/2001|