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.