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Unnamed (west of Tarr Inlet)

Occurrence in Alaska, United States with commodities Copper, Silver, Zinc
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Geologic information

Identification information

Deposit ID 10002243
MRDS ID A013145
Record type Site
Current site name Unnamed (west of Tarr Inlet)

Geographic coordinates

Geographic coordinates: -137.00212, 58.97972 (WGS84)
Relative position The occurrence is at an elevation of 1700-1800 feet about 0.75 miles southwest of the shore of Tarr Inlet and about 5 miles northwest from the mouth of the inlet. It is in the NE 1/4 SW 1/4, section 28, T. 33 S., R. 51 E., of the Copper River Meridian. The occurrence is the same as number 63 of MacKevett and others (1971, table 9), and is probably in the same general area as number 26 of Kimball and others (1978), which is in the adjacent Mt. Fairweather D-4 quadrangle. The location is probably accurate within a radius of 0.25 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Zinc Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Quartz Gangue

Alteration

  • (Local) Greenish, sericitic alteration reported by MacKevett and others, (1971, table 9).

Mineral occurrence model information

Model code 53
USGS model code 17
Deposit model name Porphyry Cu
Mark3 model number 4

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granite
    Stratigraphic age (youngest) Late Cretaceous
  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Granite

Nearby scientific data

(1) -137.00212, 58.97972
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Comments on the geologic information

  • Geologic Description = The country rocks in the area of this occurrence consist of a granitic batholith of Cretaceous age that intrudes volcanic and volcaniclastic strata of Permian age, and an intermediate area of mixed granitic and metamorphic rocks (Brew and others, 1978). ? the mineral occurrence consists of quartz monzonite that is cut by veins and veinlets of quartz which contain pyrite and chalcopyrite. MacKevett and others (1971) reported a grab sample of sericitically altered quartz monzonite contained 1000 ppm copper, 300 ppm zinc, and 1 ppm silver. The ore mineralogy, alteration, and geologic setting suggest that the occurrence is part of a porphyry copper deposit.
  • Age = Cretaceous or younger, related to quartz monzonite intrusions.

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 = Surface exposure; one sample (Hx-391, table 9, MacKevett and others, 1971) contained 1000 ppm copper, 1 ppm silver , and 300 ppm zinc).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013145
USGS Alaska Resource Data File ARDF MF046

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

    Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources, in Brew, D. A., and others, Mineral resources of the Glacier Bay National Monument wilderness study area, Alaska: U.S. Geological Survey Open-File Report 78-494, p. C1-C375.

Comments on the references

  • Primary Reference = MacKevett and others, 1971

General comments

Subject category Comment text
Deposit Model Name = Porphyry copper (Cox and Singer, 1986; model 17).
Deposit Other Comments = the occurrence is in Glacier Bay National Park and Preserve.

Reporter information

Type Date Name Affiliation Comment
Reporter 09-APR-99 Hawley, C.C. Hawley Resource Group