Unnamed (on Unavikshak Island) (ARDF #SW007) Cu

Unnamed (on Unavikshak Island)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Cu
Ore minerals	chalcopyrite; pyrite
Gangue minerals	quartz

Geographic location

Quadrangle map, 1:250,000-scale	SW
Quadrangle map, 1:63,360-scale	B-6
Latitude	56.49
Longitude	-157.72
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence is located on Unavikshak Island which is approximately 5 miles east of Cape Kumliun. No specific sites are described, however the location as plotted is accurate to within 1 mile.

Geologic setting

Geologic description The entire island has been mapped as a color anomaly (Cox and others, 1981). A mineralization system on the island has been classified by Wilson (1980) as a volcanic porphyry deposit, although no mention is made of ore or gangue minerals present. Rocks consist of andesite flows and sills of Oligocene to Pliocene age and sedimentary rocks of the Paleocene and Eocene Tolstoi Formation (Detterman and others, 1981). A hornblende andesite sill has been dated at approximately 36 m.y. and sericitic alteration at approximately 30 m.y. (Wilson, 1980).
Geologic map unit	(-157.722047548756, 56.4892350563923)
Mineral deposit model	Porphyry copper (Cox and Singer, 1986, model 17)
Mineral deposit model number	17
Age of mineralization	Tertiary.
Alteration of deposit	A small zone of sericitic alteration in undescribed rocks lies near the northern part of the island (Wilson, 1980). Propylitic and argillic types may also be present.

Production and reserves

Indication of production	None
Additional comments This site is on land selected by the Koniag Native Corporation.

References

MRDS Number	10308355
References Cox, D.P., Detra, D.E., and Detterman, R.L., 1981, Mineral resource maps of the Chignik and Sutwik Island quadrangles, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF- 1053-K, 2 sheets, scale 1:250,000. Detterman, R.L., Miller, T.P., Yount, M.E., and Wilson, F.H.,1981, Geologic map the Chignik and Sutwik Island quadrangles Alaska: U.S. Geologic Survey Miscellaneous Investigations Series Map I-1229, 1 sheet, scale 1:250,000. Wilson, F.H., 1980, Late Mesozoic and Cenozoic tectonics and age of porphyry copper prospects, Chignik and Sutwik Island quadrangles, Alaska Peninsula: U.S. Geological Survey Open-File Report 80-543, 94 p., 5 sheets, scales 1:250,000 and 1 inch = 1,000 feet.
Reporters	S.H. Pilcher (Anchorage)
Last report date	1/31/2000