Unnamed (north of mouth of Castle River)

Occurrence in Alaska, United States with commodities Silver, Barium-Barite, Lead, Zinc

Geologic information

Identification information

Deposit ID 10308050
Record type Site
Current site name Unnamed (north of mouth of Castle River)

Geographic coordinates

Geographic coordinates: -133.25888, 56.66574 (WGS84)
Relative position Coordinates are at the center of mineralized outcrops that occur discontinuously just above the high tide line for about a mile along the west shore of the large shallow bay at the mouth of the Castle River. Locality 29 of Grybeck, Berg, and Karl (1984). Probably a continuation of the mineral occurrence at PE025 described just to the northeast.
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Geographic areas

Country State
United States Alaska


Commodity Importance
Silver Primary
Barium-Barite Primary
Lead Primary
Zinc Primary

Materials information

Materials Type of material
Pyrite Ore
Sphalerite Ore

Mineral occurrence model information

Model code 184
USGS model code 28a
Deposit model name Massive sulfide, kuroko
Mark3 model number 93
Model code 187
USGS model code 28a.1
Deposit model name Massive sulfide, Sierran kuroko
Mark3 model number 44

Nearby scientific data

(1) -133.25888, 56.66574

Comments on the geologic information

  • Geologic Description = Outcrops of phyllitic, light greenish gray to cream, felsic metatuff intercalated with muscovite-rich siliceous phyllite occur discontinuously just above the high tide line for about a mile along the edge of a large shallow bay. The metatuff locally contains massive-sulfide layers up to several meters thick with abundant pyrite and sparse sphalerite(?) (Grybeck, Karl, and Berg, 1984). Grab samples of massive sulfide layers and felsic metatuff show up to 700 ppm Pb, 350 ppm Zn, 10 ppm Ag, and 2000 ppm Ba. Probably continuation of the mineralized unit at PE025 just to the northeast and thus Late Triassic in age. This is probably the locality noted by Buddington (1923) that he described as a pyrite layer about 4 feet wide exposed for 50 feet. . Brew (1997 [OF 97-156-J]) shows the deposit as part of a large unit of Mesozoic phyllite and slate with minor conglomerate, limestone, and quartzite. This unit is largely covered by vegetation and probably includes substantial additional Triassic Hyd Group rocks that host the volcanogenic massive sulfide deposits of the Duncan-Zarembo mineral belt (Berg, and Grybeck, 1980; Berg, 1981). Recent mapping by Sue Karl (oral communication, 1998) indicates that the rocks at this site are almost certainly Hyd Group strata that are in contact to the south toward the mouth of the Castle River with Mississippian and Permian argillite and volcanic graywacke of the Cannery Formation.
  • Age = Late Triassic.

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Active

Mining district

District name Kupreanof

Comments on the production information

  • Production Notes = None

Comments on the reserve resource information

  • Reserves = None

Comments on the workings information

  • Workings / Exploration = First identified by the USGS in 1979. Nine lode claims staked in the area in 1979 that probably covered this deposit. By 1995, a considerable block of ground several square miles in area was staked on and northwest of this site and PE025 (Department of Natural Resources unpublished Kardex mining claim information system). Informal discussions with industry geologists who worked in the area indicate that they found several to numerous additional occurrences of similar deposits on these claims. An aerial examination of the area in 1996 indicated no obvious signs of surface exploration in the vicinity. In 1998, there was renewed interest in the area encouraged by the geophysical surveys the State of Alaska had flown over the area.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF PE024

Bibliographic references

  • Deposit

    Buddington, A.F., 1923, Mineral deposits of the Wrangell district; U.S. Geological Survey Bulletin 739, p. 51-75.

  • Deposit

    Berg, H. C., and Grybeck, Donald, 1980, Upper Triassic volcanogenic Zn-Pb-Ag (-Cu-Au) mineral deposits near Petersburg, Alaska: U.S. Geological Survey Open-File Report 80-527, 11 p., 1 oversize sheet.

  • Deposit

    Berg, H.C., 1981, Upper Triassic volcanogenic massive sulfide metallogenic province identified in southeastern Alaska, in Albert, N.R.D., and Hudson, T.L., eds., The United States Geological Survey in Alaska: accomplishments during 1979: U.S. Geological Survey Circular 823-B, p. B104-B108.

  • Deposit

    Grybeck, D.J., Berg, H.C., and Karl, S.M., 1984, Map and description of the mineral deposits in the Petersburg and eastern Port Alexander quadrangles: U.S. Geological Survey Open-File Report 84-837, 86 p., 1 sheet, scale 1:250,000.

  • Deposit

    Brew, D.A., 1997, Reconnaissance geologic map of the Petersburg C-4 quadrangle, southeastern Alaska: U.S. Geological Survey Open-File Report 97-156-J, 21 p., 1 sheet, scale 1:63,360.

Comments on the references

  • Primary Reference = Grybeck, Berg, and Karl, 1984; this description

General comments

Subject category Comment text
Deposit Model Name = Kuroko massive-sulfide deposit model (Cox and Singer, 1986, model 28a); alternately a Sierran Kuroko deposit (Bliss, 1992; 28a1)

Reporter information

Type Date Name Affiliation Comment
Reporter 01-NOV-98 H.C. Berg and D.J. Grybeck U.S. Geological Survey