Unnamed

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu; Pb; Zn
Ore minerals chalcopyrite; galena; sphalerite
Gangue minerals calcite; pyrite

Geographic location

Quadrangle map, 1:250,000-scale SL
Quadrangle map, 1:63,360-scale B-5
Latitude 63.331
Longitude -171.371
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site is on a wave cut bench and adjacent tidal zone about 1/2 mile west of the mouth of the Okok River on the southwest coast of St. Lawrence Island. It is located within 1/4 mile and is locality 11 of Cobb (1972). Cobb (1980) summarized relevant references under the name 'Unnamed occurrence'.

Geologic setting

Geologic description

Fine-grained gabbro, exposed on the wave cut bench here, is cut by a 1- to 2-inch wide calcite vein that contains galena, sphalerite, chalcopyrite, and pyrite (Patton and Csejtey, 1971, p. C15). A sample of this vein contained 1,000 ppm silver, 1 % copper, greater than 2 % lead, and greater than 1 % zinc (Patton and Csejtey, 1971, p, C8).
Geologic map unit (-171.373756784877, 63.3300753132744)
Mineral deposit model Sulfide-bearing calcite vein in gabbro.
Age of mineralization The gabbro is mapped as part of a mafic Triassic to Permian age assemblage (based on the results of two K/Ar age determinations, 221 +/- 7 and 244 +/- 7 Ma, Patton and Csejtey, 1980). However, the calcite-sulfide vein could be Cretaceous or Tertiary, the age of younger igneous rocks on western St. Lawrence Island (Patton and Csejtey, 1980).
Alteration of deposit Alteration is not described.

Production and reserves

Workings or exploration A sample of this vein contained 1,000 ppm silver, 1 % copper, greater than 2 % lead, and greater than 1 % zinc (Patton and Csejtey, 1971, p, C8).
Indication of production None

References