Eagle Bluff

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Ag; Au; Co; Ni; Pb; Sn; Zn
Ore minerals azurite; chalcopyrite; malachite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale EA
Quadrangle map, 1:63,360-scale D-1
Latitude 64.7981
Longitude -141.1988
Nearby scientific data Find additional scientific data near this location
Location and accuracy Eagle Bluff is located along the west side of the Yukon River about 1 mile north of the town of Eagle. Eagle Bluff forms the southeast end of a northwest-trending ridge that rises approximately 1,400 feet above the Yukon River. The coordinates are on the east face of Eagle Bluff, in section 30, T. 1 S., R. 33 E., of the Fairbanks Meridian. The location is accurate. Several occurrences of mineralization are present for several miles along a northwest-southeast trend along the westward extension of Eagle Bluff. Eagle Bluff is locality 4 of Cobb (1972 [MF-393]) and locality 23 of Eberlein and others (1977).

Geologic setting

Geologic description

Eagle Bluff consists mainly of greenstone on the south and east faces; argillite crops out on the north face (Clark and Foster, 1971). The greenstone and argillite are probably equivalent to units of the Proterozoic Tindir Group; possibly the argillite is equivalent to the Adams Argillite, which is of Early Cambrian age (Foster, 1976). Limestone also crops out on Eagle Bluff, and argillite crops out for several miles from Eagle Bluff on the opposite bank of the Yukon River. The main trace of the Tintina Fault runs along the southwest side of Eagle Bluff; strands of the fault run through the bluff (Foster, 1976).
Copper minerals at Eagle Bluff include chalcopyrite, malachite, and azurite (Saunders, 1953). Chalcopyrite occurs in veins with quartz and calcite, as disseminated grains in limestone, and in amygdules in greenstone. Rock samples contain as much as 3.47 percent copper. Small patches of nickel and cobalt bloom are found in a shear zone located about 1 mile southeast of Eagle Bluff on the north side of the Yukon River, as well as on Eagle Bluff about 2 miles northwest of the Yukon River (Saunders, 1953). Several samples of sulfide ore encrusted with cobalt bloom were reportedly collected from a gold- and nickel-bearing vein on Eagle Bluff by a prospector. A variety of rock types from Eagle Bluff contain locally high but sporadic concentrations of copper (more than 10,000 ppm), lead (as much as 1,500 ppm), zinc (as much as 1,500 ppm), cobalt (as much as 2,000 ppm), silver (as much as 1.5 ppm), and tin (as much as 500 ppm) (Clark and Foster, 1971).
Eagle Bluff was visited by Wedow (1954) in 1948 in a reconnaissance for radioactive deposits in the Eagle-Nation area; he took samples but none was radioactive. Mining claims in the Eagle area were examined by Saunders (1954) in 1952. Clark and Foster (1971) conducted a geochemical and geological reconnaissance in the Seventymile River area in 1968.
Geologic map unit (-141.201112309654, 64.797823551859)

Production and reserves

Workings or exploration Eagle Bluff was visited by Wedow (1954) in 1948, in a reconnaissance for radioactive deposits in the Eagle-Nation area; he took samples, but none was no radioactive. Mining claims in the Eagle area were examined by Saunders (1954) in 1952. Clark and Foster (1971) conducted a geochemical and geological reconaissance in the Seventymile River area in 1968.
Indication of production None

References