|Quadrangle map, 1:250,000-scale||KC|
|Quadrangle map, 1:63,360-scale||A-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The approximate location of this prospect is at the south entrance of Alava Bay, about 1.8 mile southwest of Ape Point. The site is in section 6, T. 77 S., R. 94 E., of the Copper River Meridian. It corresponds to loc. 100 in Elliott and others (1978), who erroneously placed it at the north corner of Alava Bay. The location is probably accurate within about 0.5 mile.|
The country rocks at Alava Bay include: Permian marble; an assemblage of undivided Mesozoic or upper Paleozoic, metamorphosed sedimentary, volcanic, and intrusive rocks; a stock, dikes, and sills of Cretaceous granodiorite; and a plug and associated dikes of ultramafic hornblendite and pyroxenite, also of Cretaceous age (Berg and others, 1988). The marble, the undivided assemblage, and some of the Cretaceous granodiorite were regionally metamorphosed to greenschist grade in middle or Late Cretaceous time. These metamorphic rocks subsequently were remetamorphosed to hornblende hornfels grade near the contacts of intrusive rocks that were emplaced after the regional metamorphism. The structural base of the Permian marble is a thrust fault that dips gently to moderately northeast.The deposit consists of magmatic titaniferous magnetite in a Cretaceous hornblendite-pyroxenite plug or dike that apparently intrudes both the Cretaceous granodiorite and the undivided metamorphic assemblage (Berg and others, 1978, p. 24,25; Berg and others, 1988). The magnetite occurs as individual crystals and as streaks and small, podlike segregations in the ultramafic rocks. The deposit was examined by private interests in the 1960s, but the results of that examination have not been made public.
|Geologic map unit||(-131.151688589942, 55.2196624712872)|
|Mineral deposit model||Alaskan PGE (Cox and Singer, 1986; model 9).|
|Mineral deposit model number||9|
|Age of mineralization||Cretaceous.|
|Workings or exploration||The deposit was examined by private interests in the mid-1960s, but the results of that examination have not been made public.|
|Indication of production||None|
Berg, H.C., Elliott, R.L., and Koch, R.D., 1978, Map and tables describing areas of metalliferous mineral resource potential in the Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-73-M, 52 p., 1 sheet, scale 1:250,000.
Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map I-1807, 27 p., scale 1:250,000.
|Reporters||H.C. Berg, USGS|
|Last report date||7/4/1999|