|Quadrangle map, 1:250,000-scale||KC|
|Quadrangle map, 1:63,360-scale||D-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is at an elevation of about 1300 feet in the walls of a steep avalanche gully west of the Chickamin River, approximately 2.5 miles north of its confluence with the South Fork. The site is in section 5, T. 69 S., R. 96 E., of the Copper River Meridian. It corresponds to area M-3 in Berg and others (1977), and to loc. 18 in Elliott and others (1978). The location is accurate within 0.1 mile.|
The country rocks in the area of this occurrence consist chiefly of rusty-weathering pelitic paragneiss that forms roof pendants, screens, and inclusions in Tertiary or Cretaceous foliated granodiorite and quartz diorite of the Coast Range batholith (Berg and others, 1977, p. 126; Berg and others, 1988). The paragneiss probably represents marine argillaceous and clastic strata that underwent high-grade regional metamorphism in Cretaceous or Tertiary time. The premetamorphic age of the strata is uncertain, but they probably are mainly Paleozoic and may be as old as Precambrian (Berg and others, 1988, p. 26; Gehrels and others, 1990; Crawford and others, 2000).The occurrence consists of a 150-foot-thick zone of rusty-weathering paragneiss that strikes about N10W and can be traced in outcrop for about a mile northwest of Chickamin River (Berg, 1977, p. 126 and pl. 2). The zone probably is the northwest extension of a similar rusty zone on the other side of the river (KC019). The paragneiss locally contains a little pyrrhotite and a trace of chalcopyrite. Eight chip samples across about 125 feet of section perpendicular to the foliation assayed as much as 340 ppm Cu and 2 ppm Ag (Berg and others, 1977, p. 126 and fig. 35).
|Geologic map unit||(-130.725706706978, 55.9086557169598)|
|Mineral deposit model||Disseminated base-metal sulfides in rusty-weathering paragneiss|
|Alteration of deposit||Conspicuous iron-staining.|
|Workings or exploration||Eight chip samples across about 125 feet of section perpendicular to the foliation assayed as much as 340 ppm Cu and 2 ppm Ag (Berg and others, 1977, p. 126 and fig. 35).|
|Indication of production||None|
Additional commentsSite is in Misty Fiords National Monument Wilderness.
Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map I-1807, 27 p., scale 1:250,000.
Berg, H.C., Elliott, R.L., Smith, J.G., Pittman, T.L., and Kimball, A. L., 1977, Mineral resources of the Granite Fiords Wilderness Study Area, Alaska, with a section on aeromagnetic data by Andrew Griscom: U.S. Geological Survey Bulletin 1403, 151 p.
Crawford, M.L., Crawford, W.A., and Gehrels, G.E., 2000, Terrane assembly and structural relationships in the eastern Prince Rupert quadrangle, British Columbia, in H.H. Stowell and W.C.McClelland, eds., Tectonics of the Coast Mountains, southeastern Alaska and British Columbia: Geological Society of America Special Paper 343, p. 1-21.
Elliott, R.L., Berg, H.C., and Karl, S.M., 1978, map and table describing metalliferous and selected non-metalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-73-B, 17 p., 1 sheet, scale 1:250,000.
Gehrels, G.E., McClelland, W.C., Samson, S.D., Patchett, P.J., and Jackson, J.L., 1990, Ancient continental margin assemblage in the northern Coast Mountains, southeast Alaska and northwest Canada: Geology, v. 18, no. 3, p. 208-211.
|Reporters||H.C. Berg, USGS|
|Last report date||6/29/1999|