FL Feeder Prospect, Delta River Mining District, Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
FL Feeder Prospect	Prospect
Delta River Mining District	Mining District
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

Location: The FL Feeder prospect is at an elevation of about 4,700 feet one mile east of the toe of the Eureka Glacier, in the SE1/4SE1/4 section 36, T. 18 S., R. 7 E., Fairbanks Meridian. It is in a tributary to locally named Landslide Creek (see figure 3 of Rose, 1966 [ADMM GR 20]).
Geology: The rocks in the area of the FL Feeder prospect occur within a body of diorite, quartz diorite, and gabbro that intrude andesite, dacite, and graywacke (Rose, 1966 [ADMM GR 20, figure 3]). A quartz monzonite crops out to the south of the gabbro body. The gabbroic body is possibly a sill (Nokleberg and others, 1991). The FL Feeder prospect consists of chalcopyrite- and pyrite-bearing hornblende-biotite gabbro breccia that trends southeasterly and cuts the enclosing gabbro at a high angle. The breccia is intensely amphibolitized and contains large porphyroblastic biotite crystals. The chalcopyrite and pyrite occur in clasts and matrix of the breccia. Samples of breccia assay as much as 1.1 percent copper, 0.1 percent nickel, 10 parts per million silver, and 192 parts per billion gold (W.T. Ellis, written communication, 1996).
Workings: The prospect is on active Fort Knox Gold Resource claims.
Age: Late Triassic, the age of the host rock.
Alteration: Secondary amphibole and biotite are strongly developed in the FL Feeder breccia.

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

Other Databases

Link to USGS - Alaska:	MH103

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References