Unnamed (near West Twin Bay on Perry Island)

Occurrence, Inactive

Commodities and mineralogy

Main commodities W
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale C-3
Latitude 60.7244
Longitude -147.9643
Nearby scientific data Find additional scientific data near this location
Location and accuracy The occurrence is located in the SE1/4 section 1, T. 7 N., R. 8 E., of the Seward Meridian. It is situated on the east shore of West Twin Bay on the peninsula that separates West Twin Bay from East Twin Bay. This is location S-100 of Jansons and others (1984). This location is accurate to within a quarter of a mile.

Geologic setting

Geologic description

The occurrence consists of a 40-foot-wide quartz stockwork zone in granite containing aplite dikes (Jansons and others, 1984). Tysdal and Case (1979) mapped the rocks in this area as Eocene granite and granodiorite.
Some of the veins have been brecciated, and the surrounding granite is silicified. The U.S. Bureau of Mines collected samples from this prospect that contained as much as 99 ppm tungsten (Jansons and others, 1984).
Geologic map unit (-147.966356715287, 60.7238251331101)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Eocene; the occurrence is in Eocene granitic rock.
Alteration of deposit Silicification.

Production and reserves

Workings or exploration Samples collected by the U.S. Bureau of Mines contained as much as 99 ppm tungsten (Jansons and others, 1984).
Indication of production None