Maclaren Glacier lode Prospect, Valdez Creek Mining District, Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
Maclaren Glacier lode Prospect	Prospect
Valdez Creek Mining District	Mining District
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

Location: This prospect is in a lode deposit at least one-half mile long. It is on the east side of the Maclaren Glacier valley at elevations ranging from 4,000 to 5,500 feet. The location is a general or approximate midpoint location for the prospect; it is in the NW1/4NW1/4 section 6, T.19 S., R. 7 E., Fairbanks Meridian. The location corresponds to locality 7 of Rose (1966 [ADMM GR 20]), locality 27 on figure 4 of Cobb (1979 [OFR 79-238]), locality 36 in table 2 of Nokleberg and others (1991), and to the Maclaren Glacier lode (locality A9) of Kurtak and others (1992).
Geology: At the Maclaren Glacier lode prospect, a steeply dipping fault that strikes west-northwest separates interlayered Triassic limestone and gabbro (on the south) from argillite, also of Triassic age (Nokleberg and others, 1991). Locally, the argillite is intruded by granodiorite of probable Cretaceous age (Rose, 1966 [ADMM GR 20]; Nokleberg and others, 1986). Limestone is replaced by magnetite-rich skarn, but the deposit is poorly exposed because of gravel cover. The skarn contains from 10 to 20 percent magnetite, and, locally, sphalerite and chalcopyrite, which is partly oxidized to azurite and malachite. The iron-rich skarn also locally contains chromium and nickel; sample 644 of magnetite-rich skarn assayed 16.9 percent iron, 2.8 percent copper, 0.12 percent chromium, 0.14 percent nickel, 45 parts per billion (ppb) gold, and 1 ppb silver (Kurtak and others, 1992, table A9). Locally the skarn contains more zinc and precious metals; sample 79IL054A assayed 5.5 percent zinc, 2.5 percent copper, 30 parts per million (ppm) silver, and 3.7 ppm gold (Nokleberg and others, 1991).
Workings: The occurrence is covered by active MAN Resources claims (W.T. Ellis, written communication, 2001).
Age: Probably Cretaceous, associated with granitic plutonism (Nokleberg and others, 1986).

Commodities (Major) - Cu, Fe; (Minor) - Ag, Au, Cr, Ni, Zn
Development Status: None
Deposit Model: Cu skarn (?) (Cox and Singer, 1986; model 18b).

Other Databases

Link to USGS - Alaska:	MH089

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References