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  3. Mineral Resource Data System (MRDS)

Unnamed (on Dubuque Mountain)

Occurrence in Alaska, United States with commodities Silver, Molybdenum
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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. 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 10307699
Record type Site
Current site name Unnamed (on Dubuque Mountain)

Geographic coordinates

Geographic coordinates: -131.43075, 55.11774 (WGS84)
Relative position This site represents two occurrences on Dubuque Mountain: one is at an elevation of 2100 feet, 0.1 mile northwest of the peak; the other is at an elevation of 1350 feet, 0.4 mile northwest of the peak. The occurrences are in section 8, T. 78 S., R. 93 E., of the Copper River Meridian. The map site is approximately midway between the occurrences. The site corresponds to loc. 31 in Berg (1972 [I 684]), and loc. 41a, b in Karl (1992). The location is accurate within 0.1 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
Silver Primary
Molybdenum Primary

Materials information

Materials Type of material
Hematite Ore
Magnetite Ore
Pyrite Ore
Quartz Gangue

Alteration

  • (Local) Schistose trondhjemite is intensely sericitized. One iron-stained zone is associated with a dark-green intermediate dike about 10 feet thick.

Mineral occurrence model information

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

Nearby scientific data

(1) -131.43075, 55.11774
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this site are undivided, metamorphosed Silurian and Ordovician volcanic, sedimentary, and intrusive rocks; and Silurian trondhjemite that intrudes the Silurian and Ordovician rocks (Berg, 1972, Berg and others, 1988). The rocks were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. The occurrences consist of quartz fissure veins and iron-stained zones in foliated, sericitized trondhjemite, or associated with aplite and intermediate dikes that cut the trondhjemite (Berg, 1972, loc. 31; Karl, 1992, loc. 41a, b). One iron-stained zone is associated with a dark-green intermediate dike about 10 feet thick. The quartz veins contain pyrite and hematite, and the trondhjemite contains inch-long pods of magnetite and hematite. A sample of sulfide-bearing aplite contained 0.5 ppm Ag and 15 ppm Mo (Karl, 1992, loc. 41b).
  • Age = the fissure veins probably are Late Cretaceous or younger. The mineralization associated with the dikes that cut the trondhjemite probably is Tertiary.

Economic information about the deposit and operations

Development status Occurrence

Mining district

District name Ketchikan

Comments on the workings information

  • Workings / Exploration = A sample of sulfide-bearing aplite contained 0.5 ppm Ag and 15 ppm Mo (Karl, 1992, loc. 41b).

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 = Possibly low-sulfide Au-quartz veins (Cox and singer, 1986; model 36a). Disseminated magnetite mineralization of undetermined 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.