Copper Creek Prospect, Nome Mining District, Nome Census Area, Alaska, USAi

Regional Level Types
Copper Creek Prospect	Prospect
Nome Mining District	Mining District
Nome Census Area	Census Area
Alaska	State
USA	Country

Location: The Copper Creek occurrence is in the valley of Copper Creek about 0.6 mile above the confluence of Copper Creek and Nugget Creek. Nugget Creek is a east tributary to lower Grand Central River. Copper Creek heads on hill 2160. The occurrence is at an elevation of about 800 feet. It is locality 5 of Hummel (1962 [MF 248]) and locality 17 of Cobb (1972 [MF 463], 1978 [OFR 78-93]).
Geology: An incline was driven on mineralized marble on the east side of Copper Creek; it showed roughly stratabound bornite and copper carbonate minerals in bleached marble with silica-rich zones (Cathcart, 1922). Nearby schist is cut by sulfide-bearing quartz-calcite veins. Country rock at the Copper Creek occurrence is dominantly graphitic and calcareous schist with some marble layers. Locally, marble has been bleached from a characteristic blue-gray color to white. One zone about 12 feet thick has been bleached; in other places altered white marble alternates with less altered bluish marble to form a banded unit (Cathcart, 1922, p. 219-220). The rocks mainly strike northeast and dip southeast (Hummel, 1962 [MF 248]). Near the prospect, marble layers as much as 100 feet thick are interlayered with schist. This prospect appears to have similarities to several other copper-bearing deposits in the eastern Teller quadrangle (for example, the Ward mine, Hudson, 1998, TE071) and in the western Solomon quadrangle (for example, the Wheeler mine, Hudson, 1999, SO172). The metamorphic rocks here are part of the Nome Group derived from Precambrian to early Paleozoic protoliths (Thurston, 1985; Till and Dumoulin, 1994). The Nome Group underwent regional blueschist facies metamorphism in the Late Jurassic or Early Cretaceous (Sainsbury, Coleman, and Kachadoorian, 1970; Forbes and others, 1984; Thurston, 1985; Armstrong and others, 1986; Hannula and McWilliams, 1995). The blueschist facies rocks were recrystallized to greenschist facies or higher metamorphic grades in conjunction with regional extension, crustal melting, and magmatism in the mid-Cretaceous (Hudson and Arth, 1983; Miller and Hudson, 1991; Miller and others, 1992; Dumitru and others, 1995; Hannula and others, 1995; Hudson, 1994; Amato and others, 1994; Amato and Wright, 1997, 1998). Lode gold mineralization on Seward Peninsula is mostly related to the higher temperature metamorphism in the mid-Cretaceous (Apodoca, 1994; Ford, 1993 [thesis]; Ford and Snee, 1996; Goldfarb and others, 1997). The origin of the nearly stratabound copper deposits is enigmatic. They could have formed in the Proterozoic, Paleozoic or, as replacement deposits, in the Mesozoic.
Workings: Early prospecting occurred here before 1913 (Moffit, 1913); an adit had been driven about 25 feet and abandoned. Cathcart (1922) reported a shallow shaft and incline were opened on the west side of the creek; about 200 feet to the east, the zone was explored with an incline. When visited by Cathcart, the incline was filled with ice at a depth of about 20 feet.
Age: Late Proterozoic, early Paleozoic, or mid-Cretaceous.
Alteration: Marble is bleached and contains bornite and secondary copper carbonate minerals in silica-rich zones, and oxidation.

Commodities (Major) - Cu
Development Status: No
Deposit Model: Carbonate-hosted, sulfide-bearing silica-rich rock.

Other Databases

Link to USGS - Alaska:	NM053

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References