|Quadrangle map, 1:250,000-scale||MC|
|Quadrangle map, 1:63,360-scale||C-8|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is on the west valley wall of Porcupine Creek. It is at an elevation of about 4,200 feet, 4,200 feet northeast of elevation 6437, and 1,200 feet southwest of the center of section 9, T. 3 S., R. 9 E. of the Copper River Meridian. This is locality 135 of MacKevett (1976) and locality 24 of MacKevett and others (1978). The location is accurate to within about 100 feet.|
Geologic descriptionThis deposit consists of malachite-stained fault zones that contain chalcopyrite, pyrite, and possibly gold; the faults cut Triassic Nikolai Greenstone intruded by a diorite apophyses of a Jurassic pluton (Moffit and Mertie, 1923; MacKevett, 1976). The deposits were explored by short adits and opencut. The widespread deposition of copper in Triassic greenstone and limestone of the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).
|Geologic map unit||(-143.791787147343, 61.6210391753494)|
|Mineral deposit model||Basaltic Cu (Cox and Singer, 1986; model 23)|
|Mineral deposit model number||23|
|Age of mineralization||Cretaceous? The widespread deposition of copper in Triassic greenstone and limestone of the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).|
|Alteration of deposit||Oxidation.|
|Workings or exploration||The deposits were explored by short adits and opencut.|
|Indication of production||None|
Additional commentsThe locality is in the Wrangell-Saint Elias National Park and Preserve.
MacKevett, E.M., Jr., 1976, Mineral deposits and occurrences in the McCarthy quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-773-B, 2 sheets, scale 1:250,000.
MacKevett, E.M., Jr., Cox, D.P., Potter, R.W., III, and Silberman, M.L., 1997, Kennecott-type deposits in the Wrangell Mountains, Alaska--High-grade copper ores near a basalt-limestone contact, in Goldfarb, R.J., and Miller, L.D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 66-89.
MacKevett, E.M., Jr., Smith, J.G., Jones, D.L., and Winkler, G.R., 1978, Geologic map of the McCarthy C-8 quadrangle, Alaska: U.S. Geological Survey Geologic Quadrangle Map GQ-1418, 1 sheet, scale 1:63,360.
Moffit, F.H., and Mertie, J.B., Jr., 1923, The Kotsina-Kuskulana district, Alaska: U.S. Geological Survey Bulletin 745, 149 p.
|Reporters||Travis L. Hudson (Applied Geology, Inc.)|
|Last report date||1/12/2003|