Unnamed (Bristol Bay coast north of Ugashik Bay)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Fe; Ti
Ore minerals gold; ilmenite; magnetite

Geographic location

Quadrangle map, 1:250,000-scale UG
Quadrangle map, 1:63,360-scale D-5
Latitude 57.88
Longitude -157.64
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site represents beach placer deposits which extend from 4 miles north of Cape Greig (Ugashik D-5) northward to 4 1/2 miles south of Goose Point (Naknek A-5), a total of 13 miles (MacKevett and Holloway, 1977, locality 9; Church and others, 1989: MF-1539I, locality 21).

Geologic setting

Geologic description

This site represents black sand beach placer deposits tested by the U.S. Bureau of Mines in 1969 (Kimball, 1972). The beach consists of silt to large boulder-sized detritus. The coarser material is mostly of igneous origin, and is thought to have been transported from the Aleutian Range. The finer material consists mostly of quartz and feldspar.
Black sand occurs as a veneer, generally forming thin layers or lenses, that covers wide sections of the upper part of the beach. These layers or lenses rarely exceed 6 inches thick, but one layer measured 14 inches. Buried layers were generally of the same thickness. Some of the black sand lenses are up to a 100 feet long, but most are short and narrow, and rarely cover an acre. A magnetic survey failed to detect any large buried bodies of black sand. Magnetite and ilmenite are abundant in the black sands, however hypersthene is the dominant mineral.
The U.S. Bureau of Mines drilled 21 holes along 13 miles of this beach. Hole depths ranged from 2 to 4 feet. They collected 125 samples, 89 of which contained trace to 0.007 ounce of gold per ton.
Geologic map unit (-157.642099436564, 57.8792582981241)
Mineral deposit model Placer gold-PGE (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration The U.S. Bureau of Mines drilled 21 holes in these deposits in 1969 (Kimball, 1972). Of 125 samples, 89 contained trace to 0.007 ounce of gold per ton.
Indication of production None

Additional comments

This occurrence is on state land.

References