Unnamed (midway between lower Rainy Creek and Ann Creek)

Occurrences, Active

Alternative names

Southeast Rainy

Commodities and mineralogy

Main commodities Au; Cu; Ni; Pd; Pt
Other commodities Cr
Ore minerals chalcopyrite; chromite; malachite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-4
Latitude 63.3039
Longitude -145.8315
Nearby scientific data Find additional scientific data near this location
Location and accuracy The area of the occurrences is at an elevation of about 4,150 feet about midway between lower Rainy Creek and Ann Creek. It is in the NE1/4NE1/4 section 4, T. 19 S., R. 10 E., Fairbanks Meridian.

Geologic setting

Geologic description

There are three occurrences. One consists of orange lichen-covered boulders of dunite containing traces of pyrite and pyrrhotite (W.T. Ellis, oral communication, 2001). About 2,000 feet to the southwest chalcopyrite is disseminated in malachite-stained hornfelsed strata adjacent to a gabbro dike that cuts the dunite (W.T. Ellis, oral communication, 2001). A sample of chromite-bearing dunite collected about 1,000 feet to the northeast contained more than 5,000 parts per million chromium (Nokleberg and others, 1991, sample 79HZ005A). Airborne magnetic data for this area show a large circular high that connects with the southeast part of the Rainy ultramafic-mafic complex intrusive (MH164) of Late Triassic age. The complex intrudes the Slana Spur Formation of Pennsylvanian age (Nokleberg and others, 1991).
Geologic map unit (-145.833754948137, 63.303484179458)
Mineral deposit model Ni-Cu-PGE in differentiated mafic-ultramafic sill; Cu skarn (Cox and Singer, 1986; model 18b).
Mineral deposit model number 18b
Age of mineralization Late Triassic or younger.
Alteration of deposit Local serpentinization of ultramafic rocks; contact metamorphism of sedimentary rocks; oxidation of copper minerals.

Production and reserves

Workings or exploration
A sulfide-bearing dunite sample collected by American Copper And Nickel Company contained 0.43 percent nickel, 0.24 percent copper, 216 parts per billion (ppb) palladium, 295 ppb platinum, and 245 ppb gold. A sample of copper-bearing hornfels contained 8.9 percent copper, 0.006 percent zinc, and 140 ppb gold.
The occurrences are on active claims of MAN Resources.
Indication of production None