Unnamed (on southern Chilkat Peninsula)

Occurrence in Alaska, United States with commodities Silver, Gold, Copper, Zinc, Arsenic, Lead, Tungsten

Geologic information

Identification information

Deposit ID 10308235
Record type Site
Current site name Unnamed (on southern Chilkat Peninsula)

Geographic coordinates

Geographic coordinates: -135.32208, 59.11975 (WGS84)
Relative position This occurrence is at the head of a small bay on the eastern shore of the Chilkat Peninsula about 2.3 miles north of its southern tip. It is about 0.9 miles, S60E from VABM 1450 'Kal'. It is shown as number 41 on sheet 1 of Still and others (1991).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Copper Primary
Zinc Primary
Arsenic Secondary
Lead Secondary
Tungsten Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Malachite Ore
Pyrite Ore
Sphalerite Ore
Quartz Gangue

Host and associated rocks

  • Host or associated Host
    Stratigraphic age (youngest) Late Triassic

Nearby scientific data

(1) -135.32208, 59.11975

Comments on the geologic information

  • Geologic Description = Still and others (1991) indicate that this occurrence is located in metabasalt along a north-northwest-striking lineament that is likely a splay off the fault that runs through Flat Bay. Brecciated sphalerite-bearing basalt boulders up to 1 foot by 2 foot in size contained up to 6.23 ppm gold, 13 ppm silver, 27% zinc, 2,600 ppm copper, 13 ppm tungsten, and 50 ppm arsenic. Iron-stained metabasalt rubble crop with chalcopyrite, pyrite, and malachite in a quartz knot contained 0.446 ppm gold, 220 ppm zinc, and 8,400 ppm copper. A stream sediment sample 0.8 miles north of this site and along the same lineament contained 0.024 ppm gold, 1.5 ppm silver, 3,000 ppm zinc, 1,150 ppm copper, and 590 ppm lead. Plafker, Hudson, and Silberling (1979) and Plafker and Hudson (1980) note that metabasalts on the Chilkat Peninsula are vesicular and/or amygdaloidal and that well-developed pillow textures are locally present. Based in part on fossil evidence that supports a Late Triassic (Karnian) age, they suggest that the metavolcanics and carbonates may correlate with similar rocks of the Wrangellia terrane. The age of the mineralization is not well established, but can be no older than the Late Triassic age of the host rocks. If the structure that localizes the mineralization is related to the nearby Chilkat Fault, then the age of the mineralization is probably Tertiary or younger as most movement on the Chilkat Fault has been post-Mesozoic (Lanphere, 1978).
  • Age = the age of this occurrence is not well established, but can be no older than the Late Triassic age of the host rocks (Plafker, Hudson and Silberling, 1979; Plafker and Hudson, 1980). If the structure that localize the mineralization is related to the Chatham Strait Fault, then the age of the mineralization is probably Tertiary or younger as most movement on the Chilkat Fault has been post-Mesozoic (Lanphere, 1978).

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Probably inactive

Mining district

District name Juneau (Skagway subdistrict)

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF SK003

Bibliographic references

  • Deposit

    Lanphere, M.A., 1978, Displacement history of the Denali fault system, Alaska and Canada: Canadian Journal of Earth Sciences, v. 115, p. 817-822

  • Deposit

    Plafker George, Hudson, T.L., and Silberling, N.J., 1979, Upper Triassic fossils from a sequence of volcanic and sedimentary rocks on the Chilkat Peninsula, southeastern Alaska, in Johnson, K.M., and Williams, J.R., eds., The United States Geological Survey in Alaska: Accomplishments during 1978: U.S. Geological Survey Circular 804-B, p. B107-B110.

  • Deposit

    Plafker, George, and Hudson, T., 1980, Regional implications of Upper Triassic metavolcanic and metasedimentary rocks on the Chilkat Peninsula, southeastern Alaska: Canadian Journal of Earth Sciences, v. 17, p. 681-689.

  • Deposit

    Gilbert, W.G., Still, J.C., Burns, L.E., Wier, K.R., and Redman, E.C., 1991, Geochemistry of Haines-Klukwan-Porcupine area, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 91-5, 1 sheet, scale 1:63,360, 75 p.

  • Deposit

    Still, J.C., 1991, Bureau of Mines mineral investigations in the Juneau mining district, Alaska, 1984 - 1988, v. 2, Detailed mine, prospect, and mineral occurrence descriptions, section A, Haines-Klukwan-Porcupine subarea: U.S. Bureau of Mines of Mines Special Publication, 214 p.

  • Deposit

    Still, J.C., Hoekzema, R.B., Bundtzen, T.K., Gilbert, W.G., Wier, K.R., Burns, L.E., and Fechner, S.A., 1991, Economic geology of Haines-Klukwan-Porcupine area, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 91-4, 156 p., 5 sheets, scale 1:63,360.

Comments on the references

  • Primary Reference = Still and others, 1991

General comments

Subject category Comment text
Deposit Model Name = Base and precious metal mineralization localized along a lineament (shear zone?) in metabasalt. The metals have probably been derived from the host metabasalts.
Deposit Other Comments = This occurrence is within the Chilkat State Park.

Reporter information

Type Date Name Affiliation Comment
Reporter 04-FEB-01 T.C. Crafford T. Crafford & Associates