Copper Creek

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals azurite; bornite; malachite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale NM
Quadrangle map, 1:63,360-scale D-1
Latitude 64.8807
Longitude -165.1767
Nearby scientific data Find additional scientific data near this location
Location and accuracy 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]).

Geologic setting

Geologic description

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.
Geologic map unit (-165.179325970271, 64.8799442505415)
Mineral deposit model Carbonate-hosted, sulfide-bearing silica-rich rock.
Age of mineralization Late Proterozoic, early Paleozoic, or mid-Cretaceous.
Alteration of deposit Marble is bleached and contains bornite and secondary copper carbonate minerals in silica-rich zones, and oxidation.

Production and reserves

Workings or exploration 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.
Indication of production None

References

MRDS Number A012795

References

Apodoca, L.E., 1994, Genesis of lode gold deposits of the Rock Creek area, Nome mining district, Seward Peninsula, Alaska: Boulder, Colorado, University of Colorado, Ph.D. dissertation, 208 p.
Armstrong, R.L., Harakal, J.E., Forbes, R.B., Evans, B.W., and Thurston, S.P., 1986, Rb-Sr and K-Ar study of metamorphic rocks of the Seward Peninsula and southern Brooks Range, Alaska, in Evans, B.W., and Brown, E.H., eds., Blueschists and eclogites: Geological Society of America Memoir 164, p. 184-203.
Ford, R.C., 1993, Geology, geochemistry, and age of gold lodes at Bluff and Mt. Distin, Seward Peninsula, Alaska: Golden, Colorado School of Mines, Ph.D. dissertation, 302 p.
Ford, R.C., and Snee, L.W., 1996, 40Ar/39Ar thermochronology of white mica from the Nome district, Alaska--The first ages of lode sources to placer gold deposits in the Seward Peninsula: Economic Geology, v. 91, p. 213-220.
Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 151-190.
Hannula, K.A., and McWilliams, M.O., 1995, Reconsideration of the age of blueschist facies metamorphism on the Seward Peninusla, Alaska, based on phengite 40Ar/39Ar results: Journal of Metamorphic Geology, v. 13, p. 125-139.
Hannula, K.A., Miller, E.L., Dumitru, T.A., Lee, Jeffrey, and Rubin, C.M., 1995, Structural and metamorphic relations in the southwest Seward Peninsula, Alaska; Crustal extension and the unroofing of blueschists: Geological Society of America Bulletin, v. 107, p. 536-553.
Hudson, T.L., 1994, Crustal melting events in Alaska, in Plafker, G., and Berg, H. C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, Vol. G-1, p. 657-670.
Hudson, T.L., and Arth, J. G., 1983, Tin granites of Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 94, p. 768-790.
Miller, E.L., Calvert, A.T., and Little, T.A., 1992, Strain-collapsed metamorphic isograds in a sillimanite gneiss dome, Seward Peninsula, Alaska: Geology, v. 20, p. 487-490.
Thurston, S.P., 1985, Structure, petrology, and metamorphic history of the Nome Group blueschist terrane, Salmon Lake area, Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 96, p. 600-617.
Till, A.B., and Dumoulin, J.A, 1994, Geology of Seward Peninsula and St. Lawrence Island, in Plafker, G., and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, v. G-1, p. 141-152.
Reporters C.C. Hawley and Travis L. Hudson
Last report date 10/22/1999