Yellow Hill

Occurrence in Alaska, United States with commodities Chromium, PGE, Asbestos

Geologic information

Identification information

Deposit ID 10001627
MRDS ID A012391
Record type Site
Current site name Yellow Hill

Geographic coordinates

Geographic coordinates: -131.57565, 55.10585 (WGS84)
Relative position This site consists of two occurrences near Yellow Hill, in sections 16 and 17, T. 78 S., R. 92 E., of the Copper River Meridian. One is at an elevation of about 300 feet, about 0.3 mile north-northeast of the top of Yellow Hill; the other is at an elevation of about 200 feet, about 0.45 mile northwest of the top of the hill. The coordinates are for the approximate midpoint between the occurrences. The site corresponds to loc. 22 in Berg (1972 [I 684]), loc. 149 in Elliott and others (1978), and loc. 49a, b in Karl (1992). The location is accurate within about 0.1 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Chromium Primary
PGE Secondary
Asbestos Secondary

Materials information

Materials Type of material
Chromite Ore
Chrysotile Ore
Magnetite Ore

Alteration

  • (Local) Serpentinization of dunite.

Mineral occurrence model information

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

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Peridotite > Dunite
  • Host or associated Host
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Peridotite > Dunite

Nearby scientific data

(1) -131.57565, 55.10585

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this site are hornblende gabbro and partly serpentinized dunite, probably of Cretaceous age (Berg, 1972). The occurrences consist of sparse, thin veinlets, and disseminated grains, of magnetite and chromite in massive dunite that also contains abundant thin seams of chrysotile (Berg, 1972, loc. 22; Karl, 1992, loc. 49a, b). Samples of the dunite contained up to 150 ppm Co, 2000 ppm Cr, and 150 ppm Ni; and one sample yielded a value of 0.029 Pt (Berg, 1972; Karl, 1992). Most samples of dunite from the Yellow Hill area, however, showed no Pt content above the lowest limit of detection. A sample of gabbro contained 0.015 ppm Pt (Karl, 1992, loc. 49b).
  • Age = Oxide minerals probably are magmatic segregations of Cretaceous age.

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Mining district

District name Ketchikan

Comments on the workings information

  • Workings / Exploration = Samples of the dunite contained up to 150 ppm Co, 2000 ppm Cr, and 150 ppm Ni; and one sample yielded a value of 0.029 Pt (Berg, 1972; Karl, 1992). Most samples of dunite from the Yellow Hill area, however, showed no Pt content above the lowest limit of detection. A sample of gabbro contained 0.015 ppm Pt (Karl, 1992, loc. 49b).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012391
USGS Alaska Resource Data File ARDF KC153

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

    Elliott, R.L., Berg, H.C., and Karl, Susan, 1978, map and table describing metalliferous and selected nonmetalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-file Report, 78-73-B,17 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 = Berg, 1972 (I 684)

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 06-JUL-1999 H.C. Berg U.S. Geological Survey