1. Mineral Resources
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  3. Mineral Resource Data System (MRDS)

Unnamed (near Yellow Hill)

Occurrence in Alaska, United States with commodity Chromium
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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 10307695
Record type Site
Current site name Unnamed (near Yellow Hill)

Geographic coordinates

Geographic coordinates: -131.56676, 55.09574 (WGS84)
Relative position This site represents six occurrences in about a square-mile area south and east of Yellow Hill. The occurrences are in sections 16, 17, 20, and 21, T. 78 S., R. 92 E., of the Copper River Meridian. The map site is at the approximate center of this area. The site corresponds to loc. 50a-f in Karl (1992). The location is accurate within about 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
Chromium Critical Primary

Materials information

Materials Type of material
Chromite Ore
Magnetite Ore

Alteration

  • (Local) Serpentinization of dunite hostrock.

Mineral occurrence model information

Model code 23
USGS model code 9
Deposit model name Alaskan Cr-Pt (PGE)
Mark3 model number 120

Nearby scientific data

(1) -131.56676, 55.09574
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this site are serpentinized dunite and subordinate clinopyroxenite, probably of Cretaceous age (Berg, 1972 [I 684]; Berg and others, 1988). The occurrences consist of serpentinized dunite containing disseminated magnetite and chromite, and stringers of chromite. The disseminated metalliferous minerals constitute about 3 percent of the dunite. Samples of the dunite contained up to 1000 ppm Ni, 200 ppm Co, and more than 5000 ppm Cr (Karl, 1992, loc. 50a-f).
  • Age = Probably Cretaceous.

Economic information about the deposit and operations

Development status Occurrence

Mining district

District name Ketchikan

Comments on the workings information

  • Workings / Exploration = Samples of chromite- and magnetite-bearing dunite contained up to 1000 ppm Ni, 200 ppm Co, and more than 5000 ppm Cr (Karl, 1992, loc. 50a-f).

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 = Alaskan PGE (Cox and Singer, 1986; model 9)

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.