Kiruktagiak River Occurrence, Colville Mining District, North Slope Borough, Alaska, USAi

Regional Level Types
Kiruktagiak River Occurrence	Occurrence
Colville Mining District	Mining District
North Slope Borough	Borough
Alaska	State
USA	Country

Location: Located on west side of upper Kiruktagiak River, 450-1200 m above mouth of Monitis Creek. Known to within one mile.
Geology: Phosphate deposits are restricted to 40 ft. black shale and chert horizon of the Alapha Limestone of late Mississippian age. Rocks of phosphitic zone are chiefly a mixture of phosphatic material, Ca CO3, silt, and clay; in some places secondary purple fluorite is on bedding surfaces and in veinlets. Phosphatic material occurs as pellets (oolites) as much as 10 mm long and are composed of carbonate-fluorapatite. There are marked lateral variations in lithologic character and phosphate content. On the Kiraktagiak River and Monotis Creek, measured sections indicate that the phosphatic units are either lenticular or displaced by small folds and faults.
Workings: A 38 ft. thick zone of chert and shale unit in the Mississippian Alapha limestone contains an average of 12% P2O5; The upper 19 ft. averages 19% P2O5. A 27 inch thick sequence contains 27% P2O5. Samples analyzed for vanadium contained 0.07%-0.49% V2O5. Highest uranium content was 0.21% U. Samples collected by the USBM contained up to 20.6% phosphate.
Age: Mississippian

Commodities (Major) - P; (Minor) - V, U
Development Status: No
Deposit Model: Bedded phosphorite

Other Databases

Link to USGS - Alaska:	CL004

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References