|Quadrangle map, 1:250,000-scale||NB|
|Quadrangle map, 1:63,360-scale||A-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is on the side of a ridge that makes up the north wall of Carl Creek. It is at an elevation of about 6,000 feet, about 2,500 feet south of peak 7064. The prospect is about 0.3 mile east-southwest of the center of section 8, T. 3 N., R. 21 E. of the Copper River Meridian. This is locality 4 of Richter and Matson (1970 [OFR 70-275]), locality 45 of Richter and others (1975), and is included in National Park Service locality 92 (unpublished data). Cobb and Richter (1980) included this prospect under the name 'Carl Cr.'. It is located to within a few hundred feet.|
Geologic descriptionThis porphyry copper-molybdenum deposit is similar to the one at NB082, which is located 4,000 feet to the southeast. Pyrite and chalcopyrite occur in quartz veinlets and as disseminations in granodiorite and quartz monzonite of the Cretaceous, Klein Creek pluton (Richter and Matson, 1970 [OFR 70-275]; Richter and others, 1975; Richter and Jones, 1973; Richter, Lanphere, and Matson, 1975). The mineralization is in a 300- by 600-foot hydrothermally altered zone characterized by veins of quartz and sericite. Surface samples average about 0.01 percent copper and less than 0.01 percent molybdenum. A grab sample of limonite-stained granodiorite contained 1.5 parts per million (ppm) silver, 15,000 ppm copper, 15 ppm molybdenum, and 300 ppm zinc (Richter and Matson, 1970 [OFR 70-275]). The deposit is estimated to contain about 8 million tons of material that average 0.20 percent copper and very low amounts of molybdenum (Richter and others, 1975). The Klein Creek pluton has a K/Ar date of 111 +/- 3.6 Ma (Richter, Lanphere, and Matson, 1975). In the area of Carl Creek, the porphyry intrudes volcanic rocks of the Cretaceous, Chisana Formation (Richter and Jones, 1973).
|Geologic map unit||(-141.595835180756, 62.0516552153384)|
|Mineral deposit model||Porphyry Cu-Mo (Cox and Singer, 1986; model 21a)|
|Mineral deposit model number||21a|
|Age of mineralization||Cretaceous; the Klein Creek pluton has a K/Ar date of 111 +/- 3.6 Ma (Richter, Lanphere, and Matson, 1975).|
|Alteration of deposit||Quartz-sericite-pyrite veining and replacement(?). Oxidation has produced iron- and copper-staining.|
|Workings or exploration||Surface prospecting has occurred since 1967.|
|Indication of production||None|
Additional commentsThe prospect 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 Jones, D.L., 1973, Reconnaissance geologic map of the Nabesna A-2 quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-749, 1 sheet, scale 1:63,360.
Richter, D.H., and Matson, N.A., Jr., 1970, Geochemical data from the Nabesna A-2 quadrangle, Alaska: U.S. Geological Survey Open-File Report 70-275, 12 p., 1 sheet, scale 1:63,360.
Richter, D.H., Lanphere, M.A., and Matson, N.A., Jr., 1975, Granite plutonism and metamorphism, eeastern Alaska Range, Alaska: Geological Society of American Bulletin, v. 86, p. 819-820.
|Reporters||Travis L. Hudson (Applied Geology)|
|Last report date||11/24/2002|