Unnamed (south of upper Caribou Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Bi; Sn
Other commodities Ag; As; Pb; Sb; Zn
Gangue minerals calcite; chlorite; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale ID
Quadrangle map, 1:63,360-scale C-4
Latitude 62.50971
Longitude -157.86091
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is 0.2 mile southeast of hill 1,850 on a north-facing knob in the headwaters of Caribou Creek. The occurrence at an elevation of about 1,600 feet in the SW1/4 SW1/4 section 18, T. 28 N., R. 46 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description

This occurrence is a zone of extensive tourmaline-calcite-chlorite alteration in intermediate dikes that intrude shale and sandstone of the Upper Cretaceous, Kuskokwim Group (Miller and Bundtzen, 1994; Miller, Bundtzen, and Gray, 2005). The occurrence is of uncertain size and orientation. Grab samples contain up to 200 parts per million (ppm) tin, 500 ppm zinc, 500 ppm antimony, 480 ppm arsenic, 200 ppm lead, 46 ppm bismuth, and 1,000 parts per billion (ppb) silver (McGimsey and others, 1988).
Geologic map unit (-157.863308135968, 62.5090271768207)
Mineral deposit model Sn-polymetallic deposit or Polymetallic vein (Cox and Singer, 1986; model 20b or 22c).
Mineral deposit model number 20b or 22c
Age of mineralization Unknown; the dikes that intrude the Upper Cretaceous Kuskokwim Group in the area are undated.
Alteration of deposit Development of tourmaline-chlorite-calcite greisen.

Production and reserves

Workings or exploration The occurrence was sampled by the U.S. Geological Survey in the 1980s (McGimsey and others, 1988).
Indication of production None