|Quadrangle map, 1:250,000-scale||KC|
|Quadrangle map, 1:63,360-scale||D-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is at an elevation of about 2700 feet in section 4, T70S, R98E. It is near the head of an east-flowing tributary to upper Davis River and about 1.2 miles north-northeast of an unnamed lake at 3038 feet elevation. The site is in section 4, T. 70 S., R. 98 E., of the Copper River Meridian. It corresponds to area M-7 in Berg and others (1977), and to loc. 15 in Elliott and others (1978). The location is accurate within about 0.1 mile.|
The country rocks in the area of this occurrence are Tertiary or Cretaceous foliated granodiorite of the Coast Range batholith, and pelitic paragneiss that forms metamorphic roof pendants and screens in the batholith (Berg and others, 1977, p. 10; Berg and others, 1988). The paragneiss consists chiefly of quartz, biotite, feldspar, garnet, and sillimanite. It probably represents marine argillaceous and clastic sedimentary rocks 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 is a conspicuous zone of iron-stained paragneiss 120 feet wide and about 2 miles long (Berg and others, 1977, area M-7, p. 132 and pl. 2). The paragneiss contains small amounts of pyrite, pyrrhotite, and chalcopyrite that form small small pods parallel to the gneissic foliation. Two random chip samples across about half the width of the zone assayed up to 2 ppm Ag and 260 ppm Zn (Berg and others, 1977, p. 132).
|Geologic map unit||(-130.410703331894, 55.8356773675512)|
|Mineral deposit model||Sparsely disseminated base-metal sulfides|
|Alteration of deposit||Conspicuous iron-staining.|
|Workings or exploration||Two random chip samples across about 60 feet of the iron-stained zone assayed up to 2 ppm Ag and 260 ppm Zn (Berg and others, 1977, p. 132).|
|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|