Main commodities | Cu |
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Ore minerals | bornite; chalcocite; malachite |
Gangue minerals | calcite; specularite |
Quadrangle map, 1:250,000-scale | NB |
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Quadrangle map, 1:63,360-scale | A-1 |
Latitude | 62.1828 |
Longitude | -141.4276 |
Nearby scientific data | Find additional scientific data near this location |
Location and accuracy | This prospect is 2,000 feet west of upper Reynolds Creek, a south tributary to the East Fork, Snag Creek. It is at an elevation of about 5,300 feet, 5,000 feet northeast of peak 6827. The site is 0.2 mile east of the center of section 25, T. 5 N., R. 21 E. of the Copper River Meridian. This is locality 2 of Richter and others (1973) and locality 48 of Richter and others (1975). Cobb and Richter (1980) included this prospect under the name 'Reynolds'. It is located to within a few hundred feet. |
Geologic descriptionSmall veins of bornite, chalcocite, specularite, malachite, and calcite cut amygdaloidal basalt of the Triassic, Nikolai Greenstone (Moffit, 1943). The deposits were explored by several open cuts. A chip sample across 5 feet of iron-stained greenstone contained 50 parts per million (ppm) boron, 150 ppm copper, 70 ppm nickel, and 200 ppm vanadium (Matson and Richter, 1971 [OFR 71-202]). Copper mineralization is locally common in Nikolai Greenstone and is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997). | |
Geologic map unit | (-141.429740359604, 62.1824723117417) |
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Mineral deposit model | Basaltic copper (Cox and Singer, 1986; model 23) |
Mineral deposit model number | 23 |
Age of mineralization | Cretaceous? Copper mineralization is locally common in Nikolai Greenstone and is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997). |
Alteration of deposit | Low-grade metamorphic assemblages including quartz, calcite, epidote, zeolites, and some native copper replace basalt or fill amygdules (Richter and others, 1973). |
Workings or exploration | The deposits were explored by several open cuts. |
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Indication of production | None |
Additional commentsThe prospect is in the Wrangell-St. Elias National Preserve. |
MRDS Number | A011418 |
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ReferencesMacKevett, 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.
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Reporters | Travis L. Hudson (Applied Geology) |
Last report date | 11/24/2002 |