Eagle; Northern Light Prospect, Valdez Creek Mining District, Matanuska-Susitna Borough, Alaska, USAi

Regional Level Types
Eagle; Northern Light Prospect	Prospect
Valdez Creek Mining District	Mining District
Matanuska-Susitna Borough	Borough
Alaska	State
USA	Country

Also see: Silver King (HE026), Liberty (HE028) and Lucrata (HE029).
Location: The Eagle prospect is at an elevation of about 2,800 feet on Costello Creek, about 0.3 mile south-southwest of the Dunkle mine camp. It is near the east-central boundary of sec. 18, T. 19 S., R. 11 W., of the Fairbanks Meridian. Access to the Eagle prospect is via the road to the Dunkle Coal Mine. The location is accurate within 500 feet. Published maps showing this prospect are Hawley and Clark (1974) and Hawley and others (1978). This is location 1 of Cobb (1978: OFR 78-1062).
Geology: Thick Quaternary glacial deposits and Upper Tertiary sedimentary strata cover most of the older bedrock in this area. Regionally, the main geologic feature is the northeast-trending Chulitna fault, which separates a sequence of Upper Jurassic to Upper Triassic(?) crystal tuff, argillite, chert, graywacke, and limestone on the north, from Upper Devonian to Lower Triassic volcanogenic and sedimentary rocks on the south. Faulting and shearing of the rocks has occurred, along with intrusions of Late Cretaceous dikes and stocks. The Eagle prospect is a 3-foot wide quartz vein that contains pods of arsenopyrite, chalcopyrite, sphalerite, and stibnite up to 1 foot wide. The vein is spatially associated with one or more dikes. The sulfide pods contain substantial Au and Ag values. Seven chip samples of the veins averaged 0.23 ounce of gold per ton and 4.55 ounces of silver per ton (Hawley and Clark, 1974; Ross, 1933; Bundtzen, 1983). The deposit is discontinuous, owing to post mineralization faulting and to pinch-and-swell structure of the vein. The Eagle vein is subparallel and about 400 feet east of the Lucrata segment of Upper Chulitna fault.
Workings: Exploration includes a 62-foot tunnel and open cuts over a strike length of 300 to 800 feet.
Age: Probably Late Cretaceous or younger.
Reserves: Estimated at 12,000 tons (Ross, 1933).

Commodities (Major) - Ag, Au, Cu, Zn; (Minor) - Sb
Development Status: Undetermined.
Deposit Model: Polymetallic vein (Cox and Singer, 1986; model 22c)

Other Databases

Link to USGS - Alaska:	HE030

Other Regions, Features and Areas containing this locality

References