Unnamed Occurrences (ARDF - MH161; midway between lower Rainy Creek and Ann Creek); Southeast Rainy, Delta River Mining District, Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrences (ARDF - MH161; midway between lower Rainy Creek and Ann Creek); Southeast Rainy	- not defined -
Delta River Mining District	Mining District
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

Location: 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.
Geology: 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).
Workings: 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.
Age: Late Triassic or younger.
Alteration: Local serpentinization of ultramafic rocks; contact metamorphism of sedimentary rocks; oxidation of copper minerals.

Commodities (Major) - Au, Cu, Ni, Pd, Pt; (Minor) - Cr
Development Status: No
Deposit Model: Ni-Cu-PGE in differentiated mafic-ultramafic sill; Cu skarn (Cox and Singer, 19

Other Databases

Link to USGS - Alaska:	MH161

Other Regions, Features and Areas containing this locality

References