Unnamed (Two Plate Creek drainage area) (ARDF #MH081) Cu

Unnamed (Two Plate Creek drainage area)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Cu
Other commodities	Au
Ore minerals	bornite; chalcocite; chalcopyrite
Gangue minerals	carbonate mineral; epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale	MH
Quadrangle map, 1:63,360-scale	B-6
Latitude	63.2972
Longitude	-146.5903
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence, or possibly two occurrences, is on the south side of Two Plate Creek and about 2,000 feet east of the center of section 4, T. 19 S., R. 6 E., Fairbanks Meridian. The occurrence corresponds to locality 19 of Kaufman (1964), locality 23 on figure 4 of Cobb (1979 [OFR 79-238]), probably to locality 11 of Kurtak and others (1992), and possibly the Clara Marie or Kardex site number KX68-28 of Heiner and Porter (1972). Two occurrences are suggested by differences in rocks reported at the supposed site by Kaufman and by Kurtak and co-authors.

Geologic setting

Geologic description The rocks at and near the site on the south side of Two Plate Creek are reported to include greenstone and hornblende diorite (Kaufman, 1964) and argillite, hornfels, and andesite (Kurtak and others, 1992, table A11). At Kaufman's site, mineralized talus near the south valley wall contains bornite, chalcopyrite, and chalcocite associated with quartz-epidote vein material. The area is underlain by greenstone cut by hornblende diorite (Kaufman, 1964, p. 9-10). Weakly mineralized argillite and hornfels cut by quartz and quartz-carbonate veins occur in the same general area (Kurtak and others, 1992). A sample of limonite-stained argillite cut by quartz veinlets contained 2 parts per million silver and 0.43 percent copper. Gravel in Two Plate Creek is somewhat auriferous; pan-concentrate sample 1154 collected near the mouth of the creek had four very fine flakes of gold (Kurtak and others, 1992).
Geologic map unit	(-146.592567602167, 63.296768756524)
Mineral deposit model	Low-sulfide copper-bearing quartz veins; possible association with hornblende diorite intrusion or Basaltic Cu? (Cox and Singer, 1986; model 23?).
Mineral deposit model number	23?
Age of mineralization	Uncertain; possible association with a hornblende diorite pluton of Cretaceous (?) age.

Production and reserves

Workings or exploration	Two Plate Creek was located as a placer prospect in 1954 (U.S. Bureau of Mines, 1973); one lode claim, the Clara Marie, may have been staked for copper (Heiner and Porter, 1972, Kardex site number KX68-28).
Indication of production	None

References

References Cobb, E.H., 1979, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mount Hayes quadrangle, Alaska: U.S. Geological Survey Open-File Report 79-238, 140 p. Heiner, L.E., and Porter, Eve, 1972, Alaska Mineral Properties, volume 2: University of Alaska, Mineral Industry Research Laboratory Report 24, 669 p. Kaufman, M.A., 1964, Geology and mineral deposits of the Denali-Maclaren River area, Alaska: Alaska Division of Mines and Minerals Geologic Report 4, 15 p., 1 sheet, scale 1:125,000. Kurtak, J.M., Southworth, D.D., Balen, M.D., and Clautice, K.H., 1991, Mineral investigations in the Valdez Creek Mining District, south-central Alaska: U.S. Bureau of Mines Open-File Report 1-92, 658 p., 2 sheets, scale 1:250,000. U.S. Bureau of Mines, 1973, Alaska 1:250,000-scale quadrangle map overlays showing mineral deposit locations, principal minerals, and number and type of claims: U.S. Bureau of Mines Open-File Report 20-73, 95 overlays (updated in 1986, 1987).
Reporters	W.T. Ellis (Alaska Earth Science), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS)
Last report date	7/31/2001