Unnamed (east side of Queen Inlet)

Occurrence in Alaska, United States with commodities Iron, Cobalt, Copper, Molybdenum, Tin

Geologic information

Identification information

Deposit ID 10002267
MRDS ID A013170
Record type Site
Current site name Unnamed (east side of Queen Inlet)
Related records 10209660

Geographic coordinates

Geographic coordinates: -136.51405, 58.90362 (WGS84)
Relative position The location is an area on the east side of Queen Inlet near its mouth, and about 2 miles east-northeast of the north end of Composite Island. Mineralization extends about 400 feet along the shore line and extends uphill to at least 1000 feet above sealevel. The coordinates are for the approximate center of the area. The deposit is accurately located. The location is number 39 of Cobb (1972) and number 40 of MacKevett and others (1971).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Iron Primary
Cobalt Secondary
Copper Secondary
Molybdenum Secondary
Tin Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Magnetite Ore
Pyrite Ore
Calcite Gangue
Garnet Gangue
Quartz Gangue

Alteration

  • (Local) Calc-rocks have been altered to tactite composed mainly of calcite, garnet, hornblende, pyroxene and quartz. Propylitic alteration of alaskite has introduced actinolite, calcite, chlorite, and epidote. Actinolite and chlorite, with plagioclase, have also formed in the alteration of the andesite dikes.

Mineral occurrence model information

Model code 62
USGS model code 18d
Deposit model name Skarn Fe

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Marble

Nearby scientific data

(1) -136.51405, 58.90362

Comments on the geologic information

  • Geologic Description = The area is underlain by a mixed beded unit of Devonian and Silurian age that is mostly volcanic. Minor amounts of slate, argillite, and marble occur with andesitic volcanics. A major fault that strikes northwest separates the Devonian-Silurian unit from hornfels and marble of undivided Paleozoic age--this fault may mark the uphill termination of the mineral occurrence (Brew and others, 1978, pl. 1A). The bedded rocks are cut by alaskite and porphyritic dikes, probably of Tertiary age. Detailed mapping shows very complex relations (MacKevett and others, 1971, pl. 10). Magnetite occurs in tactite and marble interleaved with alaskite; the marble units generally strike east-northeast and are cut by dark porphyritic andesite dikes that strike northwest. The magnetite-rich bodies are as much as 20 feet thick. The alaskite contains numerous irregular quartz veins and irregular clots, masses and disseminations of sulfides, mainly pyrite and minor chalcopyrite. The andesite dikes also contain disseminated and blebby pyrite. Except for one sample, which contained 7 percent iron, all samples (eight total) contained greater than 10 percent iron. An 18-foot chip sample of the richest magnetite zone contained 23.4 percent iron reported as ferric oxide. The samples were anomalous in copper, cobalt, and tin.? the magnetite bodies are marked by anomalies of about 1000 gammas. Exposure is poor; magnetic anomalies on an uphill traverse were as much as 1300 gammas, probably indicating buried magnetite lenses.
  • Age = Tertiary.

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Juneau

Comments on the workings information

  • Workings / Exploration = Poorly exposed bodies of magnetite and disseminated and blebby pyrite occur in tactite, marble and alaskite. An 18-foot chip sample of the richest-appearing magnetite body contained 23.4 percent iron as ferric oxide. Seven other samples showed major (greater than 10 percent) iron. Copper, cobalt, molybdenum, tin, and zinc were detected in anomalous amounts, respectively 300 ppm, 300 ppm, 20 ppm, 30 ppm, and 300 ppm. There are no mine workings. The most detailed investigation was conducted by the Geological Survey in 1966 (MacKevett and others, 1971).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013170
USGS Alaska Resource Data File ARDF MF059

Bibliographic references

  • Deposit

    MacKevett, E.M., Jr., Brew, D.A., Hawley, C.C., Huff, L.C., and Smith, J.G., 1971, Mineral resources of Glacier Bay National Monument, Alaska: U.S. Geological Survey Professional Paper 632, 90 p., 12 plates, scale 1:250,000.

  • Deposit

    Brew, D.A., Johnson, B.R., Grybeck, D., Griscom, A., Barnes, D.F., Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources of the Glacier Bay National Monument Wilderness Study Area, Alaska: U.S. Geological Survey Open-File Report 78-494, 670 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Mount Fairweather quadrangle, AK: U.S. Geological Survey Miscellaneous Field Study Map MF-436, 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = MacKevett and others, 1971

General comments

Subject category Comment text
Deposit Model Name = Contact and porphyry mineralization, magnetite (Fe) skarn (Cox and Singer, 1986; model 18d).
Deposit Other Comments = Lenses are too small for development, but mineralization is widespread and better deposits could exist in the same system. The mineralized area is in Glacier Bay National Park and Preserve.

Reporter information

Type Date Name Affiliation Comment
Reporter 22-DEC-98 Hawley, C.C. Hawley Resource Group