Unnamed (northern Chenega Island)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Fe; Mn
Ore minerals pyrite
Gangue minerals epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale B-3
Latitude 60.3411
Longitude -148.0338
Nearby scientific data Find additional scientific data near this location
Location and accuracy The occurrence is located near the summit of hill 1640 at an elevation of about 1,600 feet. It is in the NE1/4 section 22, T. 3 N., R. 8 E., of the Seward Meridian. This is location 220 of Tysdal (1978 [MF-880-A]) and location S-88 of Jansons and others (1984). This location is accurate to within a quarter of a mile.

Geologic setting

Geologic description

The occurrence is a 15-foot-wide shear zone containing quartz-epidote veins with traces of disseminated pyrite. The zone strikes N5E and dips vertically (Kurtak and Jeske, 1986). Several quartz veins and lenses occur within the zone; the largest of these measures 4 inches wide by 2 feet long. Relic pillow textures are common in the unsheared greenstone. The bedrock in this area is Orca Group of early Tertiary age (Nelson and others, 1985).
Two chip samples were collected: one 15-foot-long sample from sheared greenstone, and one of unknown length from greenstone with remnant pillow structures. They contained from 125 to 115 ppm copper and 1,400 to 1,600 ppm manganese, respectively (Kurtak and Jeske, 1986). Tysdal (1978 [MF-880-A]) reported 15 percent iron and 1,500 ppm manganese.
Geologic map unit (-148.035882968444, 60.3405407658561)
Age of mineralization Tertiary or younger; the mineralization is in rocks of the Orca Group of Tertiary age.

Production and reserves

Workings or exploration Two chip samples were collected: one 15-foot-long sample from sheared greenstone, and one of unknown length from greenstone with remnant pillow structures. They contained from 125 to 115 ppm copper and 1,400 to 1,600 ppm manganese, respectively (Kurtak and Jeske, 1986). Tysdal (1978 [MF-880-A]) reported 15 percent iron and 1,500 ppm manganese.
Indication of production None

References