Unnamed Occurrence (ARDF - MH095; north of upper East Fork Maclaren River), Valdez Creek Mining District, Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MH095; north of upper East Fork Maclaren River)	- not defined -
Valdez Creek Mining District	Mining District
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

This is a minor copper occurrence, typical of the Nikolai Greenstone.
Location: This occurrence is at an elevation of about 4,250 feet in a south-flowing tributary of the East Fork Maclaren River about 1.5 miles west of the foot of Eureka Glacier. The tributary creek is locally called Compass Creek. The occurrence is about 500 feet west of the center of section 4, T. 19 S., R.7E., Fairbanks Meridian. The site corresponds to locality 6 on page 21 of Rose, 1966 [ADMM GR 20]) and to locality 28 in figure 4 of Cobb (1979 [OFR 79-238]). (Rose's text gives the location as T. 18 S., instead of the correct location in T. 19 S., as shown on his figure 3.)
Geology: The rock at this occurrence is metabasalt of the Nikolai Greenstone of Late Triassic age (Nokleberg and others, 1991). The formation was mapped as the Amphitheater Basalt by Rose (1966 [ADMM GR 20, figure 3]). Vesicles in propylitized basalt are filled with opal, chlorite, pyrite and minor amounts of chalcopyrite (Rose, 1966, locality 6 [ADMM GR 20, p. 21]).
Workings: The occurrence is covered by active claims of Fort Knox Gold Resources Company (W.T. Ellis, unpublished field notes, 1996).
Age: The mineralization post-dates Late Jurassic folding. It is probably either Cretaceous, related to regional metamorphism or granitic plutonism (Nokleberg and others, 1986), or early Tertiary (Stout, 1976).
Alteration: Propylitic alteration of basalt.

Commodities (Major) - Cu
Development Status: None
Deposit Model: Basaltic Cu (Cox and Singer, 1986; model 23).

Other Databases

Link to USGS - Alaska:	MH095

Other Regions, Features and Areas containing this locality

References