Unnamed Occurrence (ARDF - MH144; south of West Fork Rainy Creek), Delta River Mining District, Southeast Fairbanks Census Area, Alaska, USAi
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Latitude & Longitude (WGS84):
63° 18' 13'' North , 145° 59' 49'' West
Latitude & Longitude (decimal):
Köppen climate type:
Location: This occurrence is at an elevation of about 5,000 feet on a northeast-facing slope on the southwest side of West Fork Rainy Creek. It is in the NE1/4NW1/4 section 3, T. 19 S., R. 9 E., Fairbanks Meridian. The occurrence corresponds to locality 8 of Rose (1965), locality 1 of Cobb (1979 [OFR 79-238]), and locality S34 in table 2 of Nokleberg and others (1991).
Geology: This occurrence consists of a 2- to 3-foot-thick by 10-foot-long lens of marcasite, chalcopyrite, and minor pyrite (Rose, 1965). The lens is in the hanging wall immediately above a fault that strikes N85W and dips 40 SW. The fault cuts Triassic amphibolite and serpentinite. The rock immediately overlying the sulfide lens contains garnet, olivine(?), and pyroxene. Rock 20 feet farther from the lens is partly altered to plagioclase(?) and zeolite (Rose, 1965). The marcasite is probably an alteration product of pyrrhotite. A sample of the sulfide lens assayed 0.37 percent copper, 0.5 percent nickel, 0.03 ounce of gold per ton, and 0.33 ounce of silver per ton (Rose, 1965). A U.S. Geological Survey sample contained 0.43 percent copper and 12.5 parts per million silver (Nokleberg and others, 1991).
Workings: Surface workings are present. A sample of the sulfide lens assayed 0.37 percent copper, 0.5 percent nickel, 0.03 ounce of gold per ton, and 0.33 ounce of silver per ton (Rose, 1965 ). A U.S. Geological Survey sample contained 0.43 percent copper and 12.5 parts per million silver (Nokleberg and others, 1991). The occurrence is on active claims of MAN Resources.
Age: Late Paleozoic or younger.
Alteration: The rock immediately overlying the sulfide lens contains garnet, olivine(?), and pyroxene. Rock 20 feet farther from the lens is partly altered to plagioclase(?) and zeolite (Rose, 1965). The marcasite is probably an alteration product of pyrrhotite.
Commodities (Major) - Ag, Au, Cu, Ni; (Minor) - Pd (?), Pt (?)
Development Status: None
Deposit Model: Ni-Cu-PGE in differentiated mafic-ultramafic sill; possible Cu skarn (Cox and S
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsCommodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
3 valid minerals.
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| ⓘ | Chalcopyrite | 2.CB.10a | CuFeS2 |
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
| ⓘ | Marcasite | 2.EB.10a | FeS2 |
List of minerals for each chemical element
| S | Sulfur | |
|---|---|---|
| S | ⓘ Chalcopyrite | CuFeS2 |
| S | ⓘ Marcasite | FeS2 |
| S | ⓘ Pyrite | FeS2 |
| Fe | Iron | |
| Fe | ⓘ Chalcopyrite | CuFeS2 |
| Fe | ⓘ Marcasite | FeS2 |
| Fe | ⓘ Pyrite | FeS2 |
| Cu | Copper | |
| Cu | ⓘ Chalcopyrite | CuFeS2 |
Other Databases
| Link to USGS - Alaska: | MH144 |
|---|
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