|Quadrangle map, 1:250,000-scale||MC|
|Quadrangle map, 1:63,360-scale||C-7|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is on the west valley wall of upper Lakina River. It is at an elevation of about 4,600 feet, 4,500 feet east-southeast of elevation 5710, and 8,800 feet north-northwest of the confluence of Mill Creek and Lakina River. The site is just inside the center of the south boundary of section 34, T. 3 S., R. 11 E. of the Copper River Meridian. This is locality 101 of MacKevett (1976); the location is accurate to within about 100 feet. Cobb and MacKevett (1980) included this prospect under the name 'Lakina R.'.|
Geologic descriptionThis prospect consists of two shear zones, each less than 1 meter thick, that contain chalcocite, bornite, covellite, malachite, and azurite (Moffit and Maddren, 1909; MacKevett, 1976). The shear zones cut Triassic Nikolai Greenstone and a nearby brecciated flow top in the Nikolai contains native copper. The deposits were explored by numerous surface workings and an adit. Some exploration was done as recently as the 1950s (MacKevett, 1976).
|Geologic map unit||(-143.398483472707, 61.5581526503852)|
|Mineral deposit model||Basaltic Cu (Cox and Singer, 1986; model 23)|
|Mineral deposit model number||23|
|Age of mineralization||Cretaceous? The widespread deposition of copper in Triassic greenstone and limestone of the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).|
|Alteration of deposit||Oxidation.|
|Workings or exploration||The deposits were explored by numerous surface workings and an adit. Some exploration was done as recently as the 1950s (MacKevett, 1976).|
|Indication of production||Undetermined|
Additional commentsThe locality is in the Wrangell-Saint Elias National Park and Preserve.
Cobb, E.H., and MacKevett, E.M., Jr., 1980, Summaries of data on and lists of references to metallic and selected nonmetallic mineral deposits in the McCarthy quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-885, 156 p.
MacKevett, E.M., Jr., 1976, Mineral deposits and occurrences in the McCarthy quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-773-B, 2 sheets, 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.
Moffit, F.H., and Maddren, A.G., 1909, Mineral resources of the Kotsina-Chitina region, Alaska: U.S. Geological Survey Bulletin 374, 103 p.
Silberman, M.L., MacKevett, E.M., Jr., Connor, C.L., and Mathews, A., 1980, Metallogenic and tectonic significance of oxygen isotope data and whole-rock potassium-argon ages of Nikolai Greenstone, McCarthy quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-2019, 31 p.
|Reporters||Travis L. Hudson (Applied Geology, Inc.)|
|Last report date||1/12/2003|