|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 east nose of a low ridge along the north side of a west tributary stream to lower Nabesna Glacier. It is at an elevation of about 3,800 feet, 2,500 feet west of the glacier and about 1.6 miles east-southeast of elevation 5370. The site is in the NE1/4 of section 13, T. 4 N., R. 13 E. of the Copper River Meridian. This is locality 11 of Richter (1973), locality 21 of Richter and others (1975), and National Park Service locality WRST-29 (unpublished data). Cobb and Richter (1980) included this locality as an 'Unnamed occurrence'. It is located to within a few hundred feet.|
Geologic descriptionSmall irregular masses of pyrite and minor chalcopyrite occur in contact-metamorphosed Triassic, Nikolai Greenstone. A chip sample of pyrite-bearing greenstone contained 500 parts per million (ppm) copper, more than 100 ppm scandium, 200 ppm nickel, and 300 ppm chromium (Richter and Matson, 1970 [OFR 70-276]). This occurrence is in the contact zone of a diorite stock that is inferred to be a border phase of the mid-Cretaceous Nabesna pluton (Richter, 1973).
|Geologic map unit||(-142.938423608594, 62.1279033852809)|
|Mineral deposit model||Contact metamorphic copper deposit|
|Age of mineralization||Mid-Cretaceous? The nearby diorite stock is inferred to be a border phase of the mid-Cretaceous Nabesna pluton (Richter, 1973).|
|Alteration of deposit||Tactite development in contact metamorphosed greenstone.|
|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.
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|