1. Mineral Resources
  2. Online Spatial Data
  3. Mineral Resource Data System (MRDS)

Unnamed

Occurrence in Alaska, United States with commodities Chromium, Nickel
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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. Mineral occurrence model information
  8. Nearby scientific data
  9. Economic information about the deposit and operations
  10. Mining district
  11. Links to other databases
  12. Bibliographic references
  13. General comments
  14. Reporter information

Geologic information

Identification information

Deposit ID 10005728
MRDS ID A011565
Record type Site
Current site name Unnamed

Geographic coordinates

Geographic coordinates: -151.91172, 62.72759 (WGS84)
Relative position Reed and others (1978, locality 23) locate this occurrence in the southwest quarter of Section 33, T. 31 N., R. 14 W., of the Seward Meridian adjacent to the Dall Glacier on a ridge at about 5000 feet within Denali National Park and Preserve.

Site location context

Political divisions (FIPS codes)

Denali(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Talkeetna C-4(quadrangle 1:63,360 scale)

Talkeetna NW(quadrangle 1:100,000 scale)

Talkeetna C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

North Fork Kuskokwim River(hydrologic unit)

Upper Kuskokwim River(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Chromium Critical Primary
Nickel Critical Primary

Materials information

Materials Type of material
Chromite Ore

Mineral occurrence model information

Model code 15
USGS model code 8a
Deposit model name Podiform chromite (minor)
Mark3 model number none

Nearby scientific data

(1) g
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = Reed and others (1978) report massive and disseminated chromite within sheared ultramafic rock at this locality. This is one of several chromite occurrences in a 25-mile long belt of alpine-type ultramafic bodies that are discontinuously exposed from the Dall Glacier northeast to the Lacuna Glacier which is part of the Dall Trend, described by C.C. Hawley and Associates, Inc. (1978, Fig. 4.1-(C)3 and Fig. 4.0-B). These chromite- and magnetite-bearing dunite and peridotite sills are shown by Reed and Nelson (1980) in a narrow belt of middle to upper Paleozoic sedimentary rocks that are exposed between the middle Tertiary (38 m.y.) Foraker pluton and the northwest trending fault which places the Paleozoic rocks over Mesozoic marine sedimentary rocks (KJs). Foley and others (1997, p. 431) suggest that these ultramafic bodies may be genetically related to the composite plutons (Tcp) of Reed and Nelson (1980) in the upper Yentna River. ? Reed and others (1978) describe the occurrences in this belt of ultramafic rocks as magmatic segregations of podiform and disseminated chromite hosted in dunite sills. Chromite occurs as: (1) disseminated rounded grains 1-3 mm in diameter, (2) streaks and lenses, (3) irregular pods up to 6 feet long and (4) lens-like bodies up to 6 feet thick and 60 feet long throughout the dunite. Chromium content of 0.7 to 1% from typical dunite is given in Reed and others (1978). The average of 3 microprobe analyses of one sample: 58.4% Cr2O3, 21.1% FeO, 8.9% MgO, and 9.7% Al2O3. Other chromite occurrences in this trend are described in TL002, TL003, TL008, TL010 - 012, and TL055.
  • Age = Mesozoic and (or) Paleozoic (Reed and Nelson, 1980) or Late Cretaceous/early Tertiary (Foley and others, 1997).

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Yentna

Comments on the workings information

  • Workings / Exploration = Reconnaissance mapping, stream silt and rock sampling are all that have been done here. Chromium content of 0.7 to 1% from typical dunite is given in Reed and others (1978). The average of 3 microprobe analyses of one sample: 58.4% Cr2O3, 21.1% FeO, 8.9% MgO, and 9.7% Al2O3.

Reference information

Bibliographic references

  • Deposit

    C.C. Hawley and Associates, Inc., 1978, Mineral appraisal of lands adjacent to Mt. McKinley National Park, Alaska: U.S. Bureau of Mines Open-File Report 24-78, 275 p., 7 plates.

  • Deposit

    Reed, B.L., Nelson, S.W., Curtin, G.C., and Singer, D.A., 1978, Mineral resources map of the Talkeetna Quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-870-D, 1 sheet, scale 1:250,000.

  • Deposit

    Reed, B.L., and Nelson, S.W., 1980, Geologic map of the Talkeetna quadrangle: U.S. Geological Survey Miscellaneous Investigations Map I-1174, scale 1:250,000.

  • Deposit

    Foley, J.Y., Light, T.D., Nelson, S.W., and Harris, R.A., 1997, Mineral occurrences associated with mafic-ultramafic and related alkaline complexes in Alaska: Economic Geology, Monograph 9, p. 396-449.

  • Deposit

    MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.

Comments on the references

  • Primary Reference = Reed and others, 1978

General comments

Subject category Comment text
Deposit Model Name = Podiform chromite (Cox and Singer, 1986; model 8a).
Deposit Other Comments = Mineral occurrences in the Dall Trend are all within Denali National Park and Preserve.

Reporter information

Type Date Name Affiliation Comment
Reporter 10-AUG-1998 Madelyn A. Millholland Millholland & Associates

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.