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  3. Mineral Resource Data System (MRDS)

Unnamed (on Thomas Bay)

Prospect in Alaska, United States with commodities Gold, Arsenic, 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. 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 10000292
MRDS ID A010338
Record type Site
Current site name Unnamed (on Thomas Bay)
Related records 10258601

Geographic coordinates

Geographic coordinates: -132.79382, 56.98975 (WGS84)
Relative position Small prospect that occurs in outcrop just above the high tide level on the eastern shoreline of Thomas Bay. Near an unnamed point in the NW1/4, section 25, T. 56 S., R. 79 E. Location known to within 100 meters. Locality 20 of Grybeck, Berg, and Karl (1984).

Site location context

Political divisions (FIPS codes)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Petersburg D-3 NE(quadrangle 1:24,000 scale)

Petersburg N(quadrangle 1:100,000 scale)

Petersburg(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Central Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Arsenic Critical Secondary
Copper Secondary
Lead Secondary

Materials information

Materials Type of material
Arsenopyrite Ore
Chalcopyrite Ore
Galena Ore
Pyrite Ore
Pyrrhotite Ore
Quartz Gangue

Alteration

  • (Local) Unknown or minor.

Mineral occurrence model information

Model code 273
USGS model code 36a
Deposit model name Low-sulfide Au-quartz vein
Mark3 model number 27

Host and associated rocks

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

Nearby scientific data

(1) -132.79382, 56.98975
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = Buddington (1923) indicates that a quartz lode can be traced for about 250 feet; it consists of a sheeted zone at least 12 feet thick that may be as thick as 25-30 feet; about half of the sheeted zone is milky-white quartz and half schist. The quartz veins contain sparse, disseminated pyrite, arsenopyrite, chalcopyrite, pyrrhotite, and galena; specimens of arsenopyrite several inches across are common on the dump. Assays of selected samples show up to 3.85 ppm Au (Grybeck, Karl, and Berg, 1984). ? the country rock in the vicinity is Tertiary-Cretaceous biotite schist associated with the Coast Range metamorphic-plutonic complex to the east (Brew and others, 1984).
  • Age = Younger than the Cretaceous-Tertiary host rock.
  • Age = Host rock is Tertiary - Cretaceous.

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Probably inactive

Mining district

District name Petersburg

Comments on the production information

  • Production Notes = None

Comments on the reserve resource information

  • Reserves = None

Comments on the workings information

  • Workings / Exploration = There was some minor development on the prospect prior to 1921 and a claim was active as recently as 1979 (U. S. Bureau of Mines, 1980). Little indication of any surface activity since.

Reference information

Bibliographic references

  • Deposit

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

  • Deposit

    Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Petersburg quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-870, 53 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Petersburg quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-415, 1 sheet, scale 1:250,000.

  • Deposit

    U.S. Bureau of Mines, 1980, Claim map, Petersburg quadrangle, Alaska: U.S. Bureau of Mines Map 117, 1 sheet, scale 1:250,000.

  • Deposit

    Brew, D. A., Ovenshine, A. T., Karl, S. M., and Hunt, S. J., 1984, Preliminary reconnaissance geologic map of the Petersburg and parts of the Port Alexander and Sumdum 1:250,000 quadrangles, southeastern Alaska: U.S. Geological Survey Open-File Report 84-405, 43 p., 2 sheets, scale 1:250,000.

  • 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

    Cobb, E. H., 1972, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Petersburg Quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-870, 53 p.

Comments on the references

  • Primary Reference = Buddington, 1923

General comments

Subject category Comment text
Deposit Model Name = Low sulfide gold-quartz vein (Cox and Singer, 1986; model 36a)

Reporter information

Type Date Name Affiliation Comment
Reporter 01-NOV-1998 H.C. Berg U.S. Geological Survey
Reporter 01-NOV-1998 D.J. Grybeck 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.