|Quadrangle map, 1:250,000-scale||VA|
|Quadrangle map, 1:63,360-scale||C-1|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is on the crest of the divide between the upper Middle Fork and East Fork Copper Creek (Val Alstine and Black, 1946, plate 30); it is at an elevation of about 5,300 feet nearly in the center of the S1/2 section 30, T. 2 S., R. 8 E., of the Copper River Meridian. This prospect is approximately located, probably to within one-quarter mile. It is included in locality 72 of Cobb and Matson (1972) and locality 58 of Winkler and others (1981 [OFR 80-892-B]).|
Geologic descriptionTriassic Nikolai Greenstone is cut by shear zones that contain calcite-epidote veinlets and small amounts of pyrite, bornite, and enargite. These sulfides are also disseminated in small grains (Van Alstine and Black, 1946). This prospect was explored by two open cuts, and about 100 pounds of hand-sorted bornite and enargite were left near each cut. A polished section of this material showed covellite inclusions in enargite. Chalcocite occurs on the borders of bornite grains, as veinlets in bornite, and as irregular patches replacing bornite (Van Alstine and Black, 1946). The copper mineralization is believed to be related to the regional mineralizing event that produced the rich Kennecott copper deposits in the McCarthy quadrangle (MacKevett and others, 1997).
|Geologic map unit||(-144.032894453514, 61.6612343801654)|
|Mineral deposit model||Veins, disseminations, and fracture fillings in greenstone; probably related to Kennecott-type copper deposits (MacKevett and others, 1997)|
|Age of mineralization||The copper mineralization is believed to be related to the mineralizing event that produced the rich Kennecott copper deposits in the McCarthy quadrangle to the east (MacKevett and others, 1997). This event is interpreted to have accompanied Late Jurassic or Early Cretaceous deformation and metamorphism (MacKevett and others, 1997, p. 88).|
|Workings or exploration||Van Alstine and Black (1946) reported that two open cuts explored this prospect.|
|Indication of production||None|
Additional commentsThis prospect is within the Wrangell-St. Elias National Park.
Cobb, E.H., 1979, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Valdez quadrangle, Alaska: U.S. Geological Survey Open-File Report 79-1241, 167 p.
Cobb, E.H., and Matson, N.A., Jr., 1972, Metallic mineral resources map of the Valdez quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-438, 1 sheet, 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.
Van Alstine, R.E., and Black, R.F., 1946, Copper deposits of the Kotsina-Kuskulana district, Alaska: U.S. Geological Survey Bulletin 947-G, p. 121-141.
|Reporters||Travis L. Hudson|
|Last report date||12/14/2001|