|Quadrangle map, 1:250,000-scale||NB|
|Quadrangle map, 1:63,360-scale||D-6|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is 3,500 feet east of the Mentasta Lodge on the Glenn Highway. It is at an elevation of about 3,000 feet in the SW1/4 of section 23, T. 13 N., R. 9 E. of the Copper River Meridian. This is locality 7 of Richter (1967) and locality 3 of Richter and others (1975). The location is accurate within a few hundred feet.|
Geologic descriptionBornite and minor chalcopyrite fill vesicles and form irregular segregations disseminated through a 400-foot-thick section of Triassic, Nikolai Greenstone (Richter, 1967, 1976). The host metabasalt is highly epidotized and locally cut by veinlets of red jasper. The bornite is associated with calcite and epidote. A grab sample containing copper minerals assayed 1.1 percent copper, 0.02 ounce of gold per ton, and 0.02 ounce of silver per ton (Richter, 1967). Alteration and copper mineralization in Nikolai Greenstone 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||(-143.657397773952, 62.8874244176783)|
|Mineral deposit model||Basaltic copper (Cox and Singer, 1986; model 23)|
|Mineral deposit model number||23|
|Age of mineralization||Cretaceous? Alteration and copper mineralization in the Nikolai Greenstone 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||Epidotization.|
|Workings or exploration||There are no known workings but some surface prospecting has probably occurred.|
|Indication of production||None|
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., 1967, Geology of the upper Slana-Mentasta Pass area, southcentral Alaska: Alaska Division of Mines and Minerals Geologic Report 30, 30 p., 2 sheets, scale 1:63,360.
Richter, D.H., 1976, Geologic map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-932, 1 sheet, scale 1:250,000.
|Reporters||Travis L. Hudson (Applied Geology)|
|Last report date||11/24/2002|