Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb
Other commodities Hg; Zn
Ore minerals pyrite
Gangue minerals chalcedony; epidote

Geographic location

Quadrangle map, 1:250,000-scale AD
Quadrangle map, 1:63,360-scale C-2
Latitude 51.9161
Longitude -176.6131
Nearby scientific data Find additional scientific data near this location
Location and accuracy Quarry at north end of Adak Naval Air Station developed area. About 1 mi (1.6 km) east of southern tip of Andrew Lake.

Geologic setting

Geologic description

Mineral occurrence is located in quarry in volcanic rocks of either the Finger Bay Volcanics or the Andrew Lake Formation. Dominant lithology is a massive andesite(?) cut by faults trending approximately east-west. A zone of iron-staining, possibly centered on a sheer zone or fault cuts through the quarry. Stained zone is approximately 10 to 15 meters wide and the included rocks contain variable amounts of pyrite.
Geologic map unit (-176.615580089651, 51.9147220265233)
Age of mineralization Tertiary.
Alteration of deposit Propylitic alteration characterized by silicification and replacement of mafic minerals by epidote and chlorite.

Production and reserves

Workings or exploration A number of samples (93AWs 14a-i) were collected during brief U.S. Geological Survey reconnaissance studies in 1993. Samples yielded as much as 4 ppb Au, 0.11 ppm Hg, 310 ppm Cu, 0.31 ppm Ag, 270 ppm Pb, and 190 ppm Zn.
Indication of production None


MRDS Number A106033
Reporters F.H. Wilson, T.D. Light
Last report date 2/22/1996