Unnamed Occurrence (ARDF - MH134; east of peak 6346), Delta River Mining District, Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MH134; east of peak 6346)	- not defined -
Delta River Mining District	Mining District
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

Location: This occurrence is on the southeast side of a ridge about 0.4 mile southeast of the top of peak 6346 at an elevation of about 5,900 feet. It is on the west side of the North Fork Rainy Creek about 0.4 mile west of the center of section 26, T. 18 S., R. 9 E., Fairbanks Meridian.
Geology: The Rainy mafic-ultramafic complex is a steeply north dipping dike-like body of dunite that varies from less than 100 feet thick to more than 6,000 feet thick and extends for more than 12 miles in length. A discontinuous marginal gabbro package extends along most of the southern (lower) contact and is more discontinuous along the northern (upper) contact (W.T. Ellis, oral communication, 2001). The Rainy complex of Late Triassic age intrudes the Slana Spur Formation of Pennsylvanian age in the Wrangellia terrane (Nokelberg and others, 1992). On the western side of the complex the layered marginal gabbro sequence is as much as 1,500 feet thick. Prominent rock types are gabbronorites, very coarse grained clinopyroxene mafic gabbro, wherlite, and mineralized mafic gabbro. The mineralized gabbro contains 5 to 15 percent disseminated pyrrhotite with minor chalcopyrite and pentlandite and is iron and copper stained. Two anomalous samples contained 0.15 to 0.23 percent copper, 0.12 to 0.21 percent nickel, 153 to 180 parts per billion (ppb) palladium, 58 to 72 ppb platinum, and 18 to 51 ppb gold (W.T. Ellis, oral communication, 2001).
Workings: Exploration on the Rainy property was carried out by American Copper and Nickel Company (ACNC) working with Fort Knox Gold Resources Inc. Exploration since 1994 includes sampling, airborne and ground geophysical surveys, and one diamond drill hole (W.T. Ellis, oral communication, 2001). Two anomalous samples contained 0.15 to 0.23 percent copper, 0.12 to 0.21 percent nickel, 153 to 180 parts per billion (ppb) palladium, 58 to 72 ppb platinum, and 18 to 51 ppb gold (W.T. Ellis, oral communication, 2001). The nearby East Peak occurrence (MH135) was discovered and staked by ACNC in 1995, but the claims were allowed to lapse in 1999. The occurrence is now on active MAN Resources claims.
Age: Late Triassic, synchronous with emplacement of Rainy complex.
Alteration: The coarse-grained clinopyroxene olivine gabbro (melagabbro) is variably serpentinized.

Commodities (Major) - Au, Cu, Ni, Pd, Pt
Development Status: None
Deposit Model: Ni-Cu-PGE in differentiated mafic-ultramafic sill.

Other Databases

Link to USGS - Alaska:	MH134

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