Unnamed (on Calico Bluff)

Occurrence, Inactive

Commodities and mineralogy

Main commodities U
Other commodities V

Geographic location

Quadrangle map, 1:250,000-scale EA
Quadrangle map, 1:63,360-scale D-1
Latitude 64.9093
Longitude -141.1923
Nearby scientific data Find additional scientific data near this location
Location and accuracy Calico Bluff is located on the west bank of the Yukon River about 12 miles downstream from the town of Eagle. The coordinates are the approximate center of the outcrop of the Calico Bluff Formation along the Yukon River, in the SW1/4 section 14, T. 1 N., R. 32 E., of the Fairbanks Meridian. The location is accurate. Calico Bluff is locality 11 of Eberlein and others (1977).

Geologic setting

Geologic description

The Calico Bluff Formation consists of rhythmically interbedded, bioclastic limestone and dark brownish-gray shale; it is about 1,400 feet thick (Foster, 1976). The Calico Bluff Formation contains rich invertebrate fauna and a few gymnosperm pollen grains and spores; it is of Late Mississippian to Early Pennsylvanian age (Foster, 1976).
In 1948, Wedow (1954) collected samples at scattered outcrops of the Calico Bluff Formation, from Calico Bluff to the Tatonduk River, during a reconnaissance for radioactive deposits in the Eagle-Nation area. Two units of black shale are slightly radioactive; both are near the base of the Calico Bluff Formation (Wedow, 1954). Selected samples that showed anomalous radioactivity in the field were assayed. They contain 0.001 to 0.005 percent uranium. A select sample of phosphatic material contains 0.019 percent uranium, and a sample of fossiliferous gray-black shale with a bluish phosphate bloom contains 0.009 percent uranium; these samples contain 0.46 and 0.68 percent V2O5, respectively (Wedow, 1954).
Geologic map unit (-141.19462488063, 64.9090246845822)
Mineral deposit model Sandstone U? (Cox and Singer, 1986; model 30c).
Mineral deposit model number 30c?
Age of mineralization The Calico Bluff Formation is of Late Mississippian to Early Pennsylvanian age (Foster, 1976).

Production and reserves

Workings or exploration In 1948, Wedow (1954) collected samples at scattered outcrops of the Calico Bluff Formation, from Calico Bluff to the Tatonduk River, during a reconnaissance for radioactive deposits in the Eagle-Nation area. Two units of black shale are slightly radioactive; both are near the base of the Calico Bluff Formation (Wedow, 1954). Selected samples that showed anomalous radioactivity in the field were assayed. They contain 0.001 to 0.005 percent uranium. A select sample of phosphatic material contains 0.019 percent uranium, and a sample of fossiliferous gray-black shale with a bluish phosphate bloom contains 0.009 percent uranium; these samples contain 0.46 and 0.68 percent V2O5, respectively (Wedow, 1954).
Indication of production None

References