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  3. Mineral Resource Data System (MRDS)

Unnamed (near head of Annette Bay)

Occurrence in Alaska, United States with commodities Gold, Copper, Lead
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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. Host and associated rocks
  9. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. General comments
  15. Reporter information

Geologic information

Identification information

Deposit ID 10307677
Record type Site
Current site name Unnamed (near head of Annette Bay)

Geographic coordinates

Geographic coordinates: -131.51776, 55.24074 (WGS84)
Relative position This site represents seven occurrences distributed in a triangular lowland area of about a square mile, whose apices are near the east foot of Nubbins Mountain, the northeast foot of Bush Mountain, and the northeast head of Annette Bay. The occurrences are in sections 25, 35, and 36, T. 76 S., R. 91 E., of the Copper River Meridian. The coordinates are for the approximate center of the area of occurrences. The site corresponds to loc. 5a-g in Karl (1992). The location is accurate within about 0.2 mile.

Site location context

Political divisions (FIPS codes)

Prince of Wales-Hyder(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ketchikan A-5(quadrangle 1:63,360 scale)

Ketchikan SW(quadrangle 1:100,000 scale)

Ketchikan(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Ketchikan(hydrologic unit)

Southern Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Annette Island Indian Reservation(American Indian Reservation)

American Indian Reservation BIA(Type of land area)

BIA(Federal land areas administered by BIA)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Copper Primary
Lead Primary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore

Alteration

  • (Local) Diorite hostrock is propylitized.

Host and associated rocks

  • Host or associated Host
    Rock type
    Stratigraphic age (youngest) Cretaceous
    Stratigraphic age (oldest) Jurassic

Nearby scientific data

(1) -131.51776, 55.24074
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this site are Upper Jurassic or Cretaceous andesitic or basaltic metavolcanic rocks that are gradationally interbedded with subordinate flyschlike metasedimentary rocks (Berg, 1972 [I 684]; Berg and others, 1988). The bedded rocks are intruded by a Jurassic or Cretaceous stock and dikes of diorite and quartz diorite. The rocks were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. The occurrences all are in propylitized diorite that contains about 5 percent of disseminated pyrite, and pyrite seams along fractures (Karl, 1992, loc. 5a-g). Samples of the diorite contained up to 0.26 ppm Au, 300 ppm Cu, 1500 ppm Zn, and 10 ppm Mo; a sample of chalcopyrite-bearing diorite near its contact with the bedded rocks contained 300 ppm Cu. The distribution and setting of the disseminated sulfide mineralization suggest that it may in part be cogenetic with Jurassic or Cretaceous emplacement of the diorite hostrock.
  • Age = Disseminated sulfide mineralization may in part be cogenetic with Jurassic or Cretaceous emplacement of the diorite hostrock.

Economic information about the deposit and operations

Development status Occurrence

Mining district

District name Ketchikan

Comments on the workings information

  • Workings / Exploration = Samples of the diorite contained up to 0.26 ppm Au, 300 ppm Cu, 1500 ppm Zn, and 10 ppm Mo; and a sample of chalcopyrite-bearing greenstone near a diorite contact contained 300 ppm Cu (Karl, 1992, loc. 5a-g).

Reference information

Bibliographic references

  • Deposit

    Berg, H.C., 1972, Geologic map of Annette Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-684, 8 p., 1 sheet, scale 1:63,360,

  • Deposit

    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 MF-1807,27 p., scale 1:250,000.

  • Deposit

    Karl, S.M., 1992, Map and table of mineral deposits on Annette Island, Alaska: U.S. Geological Survey Open-File Report 92-690, 57 p., 1 map, scale 1:63,360.

Comments on the references

  • Primary Reference = Karl, 1992

General comments

Subject category Comment text
Deposit Model Name = Disseminated sulfide deposit of late magmatic origin?

Reporter information

Type Date Name Affiliation Comment
Reporter 07-JUL-99 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.