Unnamed Occurrence (ARDF - MH241; east of mile 195 on Richardson Highway), Chistochina Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MH241; east of mile 195 on Richardson Highway)	- not defined -
Chistochina Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

Location: This occurrence is at an elevation of 3,600 feet, 0.75 mile due east of mile 195 on the Richardson Highway. It is at the northeast corner of section 5, T. 20 S., R. 12 E., Fairbanks Meridian.
Geology: The rock exposed at this site is mainly Upper Triassic coarse-grained to pegmatitic olivine melagabbro containing 20 percent olivine, 70 percent clinopyroxene, and 10 percent intercumulus plagioclase. Mineralization consists of chalcopyrite, pentlandite, and pyrrhotite in iron-stained, magnetite-bearing skarn of intergrown clinopyroxene and amphibole. The olivine in the melagabbro is partly serpentinized, and the pyroxene is mostly altered to amphibole. A sample of the mineralized rock contained 1.07 percent copper, 1.58 percent nickel, 484 parts per billion (ppb) palladium, 300 ppb platinum, and 110 ppb gold. (The source of all this information is W.T. Ellis, oral communication, 1998.)
Workings: A sample of the mineralized rock contained 1.07 percent copper, 1.58 percent nickel, 484 parts per billion (ppb) palladium, 300 ppb platinum, and 110 ppb gold (W.T. Ellis, oral communication, 1998). The prospect had been staked, but the area is closed to mineral entry because it is in the Alyeska pipeline corridor.
Age: Late Triassic.
Alteration: The olivine is partly serpentinized, and the pyroxene is mostly altered to amphibole. There is also local iron staining.

Commodities (Major) - Cu, Ni, Pd, Pt
Deposit Model: Ni-Cu-PGE in differentiated mafic-ultramafic sill.

Other Databases

Link to USGS - Alaska:	MH241

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