|Quadrangle map, 1:250,000-scale||NB|
|Quadrangle map, 1:63,360-scale||A-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is on the low, west-facing slopes along the east side of Nabesna Glacier. It is at an elevation of about 4,800 feet, 1,500 feet east of the glacier, and 2,800 feet south-southwest of elevation 5570. The occurrence is about 0.6 mile southeast of the center of section 16, T. 3 N., R. 14 E. of the Copper River Meridian. This is locality 18 of Richter (1973), locality 28 of Richter and others (1975), and National Park Service locality WRST-47 (unpublished data). Cobb and Richter (1980) included this locality as an 'Unnamed occurrence'. It is located to within a few hundred feet.|
Geologic descriptionThis is a 30- by 200-foot zone of malachite- and azurite-stained amygdaloidal basalt (Richter and others, 1975). A composite chip sample across 50 feet of copper-stained basalt contained more than 20,000 parts per million (ppm) copper and 1.5 ppm silver (Richter and Matson, 1970 [OFR 70-276]). The basalt is part of the Triassic, Nikolai Greenstone (Richter, 1973). 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||(-142.846223154967, 62.0330971577391)|
|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).|
|Indication of production||None|
Additional commentsThe occurrence is in the Wrangell-St. Elias National Preserve.
Cobb, E.H., and Richter, D.H., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Nabesna quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-927, 117 p.
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.
Richter, D.H., and Matson, N.A., Jr., 1970, Geochemical data from the Nabesna A-4 quadrangle, Alaska: U.S. Geological Survey Open-File Report 70-276, 14 p., 1 sheet, scale 1:63,360.
|Reporters||Travis L. Hudson (Applied Geology)|
|Last report date||11/24/2002|