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  3. Alaska Resource Data File (ARDF)

Okpilak River

Occurrence, Inactive

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Commodities and mineralogy

Main commodities Mo; U
Other commodities F; REE
Ore minerals molybdenite
Gangue minerals fluorite; yttrocerite

Geographic location

Quadrangle map, 1:250,000-scale ML
Latitude 69.3
Longitude -144.02
Nearby scientific data Find additional scientific data near this location
Location and accuracy Accurate to within 1.6 kilometers (1 mi). Grybeck, 1977, p. 40, Location 13.

Geologic setting

Geologic description

Fluorite, molybdenite and (?)yttrocerite occur in samples of granite of Okpilak batholith. Representative sample in peripheral zone of granite contains 50 ppm eU. Heavy mineral fractions of concentrates contain 0.034-0.080% eU and 0.010-0.033% U.
Geologic map unit (-144.022736510915, 69.2997588006496)
Mineral deposit model Disseminated, felsic-hosted
Age of mineralization Probably Early Devonian

Production and reserves

Workings or exploration None
Indication of production None

References

MRDS Number A106145

References

Grybeck, Donald, 1977, Map showing known mineral deposits of the Brooks Range, Alaska: U.S. Geological Survey Open-File Report 77-166-C, 45 p., 1 sheet, scale 1:1,000,000.
Reporters Schmidt, J.M., Kelley, J.S.
Last report date 9/15/1996