Old Harbor

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals chalcopyrite; pyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale KD
Quadrangle map, 1:63,360-scale A-5
Latitude 57.14
Longitude -153.34
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is located on the northwest side of Sitkalidak Island approximately 5 miles south of Old Harbor (Berg and Cobb, 1967, figure 15, locality 14; Cobb, 1972, MF 460, locality 6; MacKevett and Holloway, 1977, locality 6).

Geologic setting

Geologic description

A sulfide-bearing shear zone is present along a footwall contact between a gabbro sill and Cretaceous metasedimentary rock. The shear zone is 10 to 20 feet in width and extends for approximately 2500 feet. Pyrite, pyrrhotite, and sparse chalcopyrite are disseminated in the shear zone. In addition, several sulfide masses containing abundant chalcopyrite occur about 1250 feet apart. Assays range from 0.9 percent copper in the disseminated mineralization to 5.52 percent in the chalcopyrite-rich zones (Berg and Cobb, 1967, p. 87).
Geologic map unit (-153.342253684414, 57.1392139661223)
Mineral deposit model Shear zone with minor copper values.
Age of mineralization Cretaceous or younger

Production and reserves

Workings or exploration Assays range from 0.09 percent copper in disseminated material to 5.52 percent copper in one chalcopyrite-rich mass. The shear zone was prospected by 3 short adits prior to WW II.
Indication of production None

Additional comments

Site is on land conveyed to the Koniag Corporation.

References