Unnamed Occurrence (ARDF - MH271; near the glacier at the head of the West Fork Chistochina River), Chistochina Mining District, Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MH271; near the glacier at the head of the West Fork Chistochina River)	- not defined -
Chistochina Mining District	Mining District
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

Location: This occurrence is southeast of the terminus of the glacier at the the head of West Fork Chistochina River and at an elevation of about 4,100 feet. It is in the W1/2NE1/4 section 13, T. 20 S., R. 14 E., Fairbanks Meridian. The occurrence corresponds to locality 9 on figure 1 of Rose (1967) and locality 2 on figure 6 of Cobb (1979 [OFR 79-238]). The location is probably accurate within 1,000 feet.
Geology: The rocks near this site are andesite of the Slana Spur Formation of Pennsylvanian to Permian age (Richter and Dutro, 1975). The andesite is intruded by Mesozoic (?) quartz monzonite and is partly replaced by pods as much as 5 feet wide that have abundant chalcopyrite, pyrite, and magnetite in a gangue of quartz, epidote, chlorite, and an unspecified carbonate mineral (Rose, 1967). Rose found a boulder near the site that contained rhodonite, rhodochrosite, and quartz but could not determine if it was locally derived or transported.
Workings: The natural exposure of mineralized andesite is in an abandoned stream channel; the occurrence was not found during the investigations of I.M. Lange and W.J. Nokleberg in 1979 and 1980.
Age: Possibly Mesozoic, on the basis of the association with a quartz monzonite pluton of that age.
Alteration: Replacement of andesite by masses of skarn-like pyrite-chalcopyrite-magnetite accompanied by chlorite, epidote, quartz, and a carbonate mineral.

Commodities (Major) - Cu; (Minor) - Fe, Mn
Development Status: None
Deposit Model: Cu skarn (Cox and Singer, 1986; model 18b).

Other Databases

Link to USGS - Alaska:	MH271

Other Regions, Features and Areas containing this locality

References