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Japan Bay

Prospect in Alaska, United States with commodities Silver, Barium-Barite, Lead, Zinc
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Economic information about the deposit and operations
  12. Mining district
  13. Links to other databases
  14. Bibliographic references
  15. General comments
  16. Reporter information

Geologic information

Identification information

Deposit ID 10001614
MRDS ID A012378
Record type Site
Current site name Japan Bay

Geographic coordinates

Geographic coordinates: -131.57676, 55.1778 (WGS84)
Relative position This site, informally called the Japan Bay prospect, is on the southwest shore of inner Sylburn Harbor, about 0.5 mile from its head. The site is in section 20, T. 77 S., R. 92 E., of the Copper River Meridian. It corresponds to loc. 18 in Berg (1972 [I 684]), loc. 136 in Elliott and others (1978), and loc. 19 in Karl (1992). The location is accurate within a few hundred feet.

Site location context

Political divisions (FIPS codes)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ketchikan A-5 NW(quadrangle 1:24,000 scale)

Ketchikan SW(quadrangle 1:100,000 scale)

Ketchikan(quadrangle 1:250,000 scale)

Federal lands

Annette Island Indian Reservation(American Indian Reservation)

American Indian Reservation UND(Type of land area)

UND(Federal land areas administered by UND)

Geographic areas

Country State
United States Alaska

Commodities

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

Materials information

Materials Type of material
Barite Ore
Galena Ore
Pyrite Ore
Sphalerite Ore
Calcite Gangue
Hematite Gangue

Alteration

  • (Local) Probable local permeation of some of the country rocks by hydrothermal hematite.

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Stratigraphic age (youngest) Late Permian
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite

Nearby scientific data

(1) -131.57676, 55.1778
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this site are recrystallized, locally intensely sheared and hematite?-altered, Upper Triassic rhyolite and limestone (Berg, 1972). The rocks are complexly folded and faulted, and were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time.? the deposit consists chiefly of barite veins in a 10-foot-wide shear zone in brecciated rhyolite (Karl, 1992, loc. 19). The veins contain minor quartz and calcite, and clots, laminae, and stringers of hematite, galena, and sphalerite. Barite forms irregular veins and masses up to 3 feet wide. The sheared rhyolite contains disseminated sulfides.? the prospect was explored in the 1970s and 1980s by private interests (Hawley and Associates, in Karl, 1992). The work included 5 diamond drill holes, soil surveys, and other studies. The drill holes indicated that the barite zone dips 25 W, and barite was intercepted as deep as 150 feet. The soil surveys indicated that the barite zone is about 100 feet wide and extends about 1000 feet to the south. The barite lenses and veins are sparse and irregular, and barite grade is low, but the deposit size is estimated to exceed 1,000,000 tons. Karl's (1992, loc. 19a, b) samples of the barite and of variously mineralized country rocks contained as much as 0.11 ppm Au, 50 ppm Ag, 1% Pb, 700 ppm Zn, and 10 ppm Mo.
  • Age = Late Triassic or younger.

Economic information about the deposit and operations

Development status Prospect
Commodity type Both

Mining district

District name Ketchikan

Comments on the reserve resource information

  • Reserves = the deposit size is estimated to exceed 1,000,000 tons (Karl, 1992, loc. 19).

Comments on the workings information

  • Workings / Exploration = The prospect was explored in the 1970s and 1980s by private interests (Hawley and Associates, in Karl, 1992, loc. 19). The work included 5 diamond drill holes, soil surveys, and other studies. The drill holes indicated that the barite zone dips 25 west, and barite was intercepted as deep as 150 feet. The soil surveys indicated that the barite zone is about 100 feet wide and extends about 1000 feet to the south. The barite lenses and veins are sparse and irregular, and barite grade is low, but the deposit size is estimated to exceed 1,000,000 tons. Karl's (1992, loc. 19a, b) samples of the barite and of variously mineralized country rocks contained as much as 0.11 ppm Au, 50 ppm Ag, 1% Pb, 700 ppm Zn, and 10 ppm Mo.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Karl, 1992

General comments

Subject category Comment text
Deposit Model Name = Polymetallic veins (Cox and Singer, 1986; model 22c)

Reporter information

Type Date Name Affiliation Comment
Reporter 06-JUL-1999 H.C. Berg U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.