|Quadrangle map, 1:250,000-scale||KC|
|Quadrangle map, 1:63,360-scale||A-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This site represents six occurrences in about a square-mile area south and east of Yellow Hill. The occurrences are in sections 16, 17, 20, and 21, T. 78 S., R. 92 E., of the Copper River Meridian. The map site is at the approximate center of this area. The site corresponds to loc. 50a-f in Karl (1992). The location is accurate within about 0.1 mile.|
Geologic descriptionThe country rocks in the area of this site are serpentinized dunite and subordinate clinopyroxenite, probably of Cretaceous age (Berg, 1972 [I 684]; Berg and others, 1988). The occurrences consist of serpentinized dunite containing disseminated magnetite and chromite, and stringers of chromite. The disseminated metalliferous minerals constitute about 3 percent of the dunite. Samples of the dunite contained up to 1000 ppm Ni, 200 ppm Co, and more than 5000 ppm Cr (Karl, 1992, loc. 50a-f).
|Geologic map unit||(-131.566677613944, 55.0956578201874)|
|Mineral deposit model||Alaskan PGE (Cox and Singer, 1986; model 9).|
|Mineral deposit model number||9|
|Age of mineralization||Probably Cretaceous.|
|Alteration of deposit||Serpentinization of dunite hostrock.|
|Workings or exploration||Samples of chromite- and magnetite-bearing dunite contained up to 1000 ppm Ni, 200 ppm Co, and more than 5000 ppm Cr (Karl, 1992, loc. 50a-f).|
|Indication of production||None|
Berg, H.C., 1972, Geologic map of Annette Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-684, 8 p., 1 sheet, scale 1:63,360.
|Reporters||H.C. Berg, USGS|
|Last report date||7/7/1999|