|Quadrangle map, 1:250,000-scale||SI|
|Quadrangle map, 1:63,360-scale||A-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is at an elevation of about 2,400 feet on the ridge west of upper Indian River, about 0.8 mile northeast of hill 2505. The occurrence is 0.1 mile southwest of the center of sec. 18, T. 55 S., R.64 E. It is location P-111 of Bittenbender and others (1999); location 53 of Cobb (1972, 1978); and MAS no. 0021140001 (U.S. Bureau of Land Management, 2002). The location is accurate within 0.5 mile.|
Geologic descriptionThis occurrence consists of magnetite and chromite in serpentine. Loney and others (1963, 1975) map this small Mesozoic serpentinite body (sliver?) in rocks of the Jurassic and Triassic, Kelp Bay Group which consists of phyllite, greenschist, greenstone, graywacke, and semischist that has been cataclastically deformed. There is no indication that the magnetite and chromite are other than normal trace minerals in the serpentine. Spectrographic analysis indicates a small amount of nickel in the samples but probably no more than the expected level of background in serpentine.
|Geologic map unit||(-135.302261265417, 57.0995387297852)|
|Mineral deposit model||Minor magnetite and chromite in serpentine.|
|Age of mineralization||The magnetite and chromite was probably contemporaneous with the solidification of the ultramafic rock that was altered to serpentine in the Mesozoic.|
|Workings or exploration||Only surface sampling.|
|Indication of production||None|
Bittenbender, P., Still, J.C., Maas, K., and McDonald, M., Jr., 1999, Mineral resources of the Chichagof and Baranof Islands area, southeast Alaska: Bureau of Land Management, BLM-Alaska Technical Report 19, 222 p.
Cobb, E.H., 1972, Metallic mineral resources map of the Sitka quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-467, scale 1:250,000.
Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Sitka quadrangle: U.S. Geological Survey Open-File Report 78-450, 124 p.
Loney, R.A., Berg, H.C., Pomeroy, J.S., and Brew, D.A., 1963, Reconnaissance geologic map of Chichagof Island and northwestern Baranof Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-388, 1 sheet, scale 1:250,000.
Loney, R.A., Brew, D.A., Muffler, L.J.P., and Pomeroy, J.S., 1975, Reconnaissance geology of Chichagof, Baranof, and Kruzof Islands, southeastern Alaska: U.S. Geological Survey Professional Paper 792, 105 p.
U.S. Bureau of Land Management, 2002, Alaska mineral locations database report (Sitka quadrangle), July 2, 2002, 205 p. [http://imcg.wr.usgs.gov/dem.html]
|Reporters||Donald Grybeck (U.S. Geological Survey)|
|Last report date||5/5/2005|