Unnamed (east of Blunt Mountain)

Occurrence in Alaska, United States with commodities Silver, Gold, Copper, Lead, Zinc

Geologic information

Identification information

Deposit ID 10001620
MRDS ID A012384
Record type Site
Current site name Unnamed (east of Blunt Mountain)

Geographic coordinates

Geographic coordinates: -131.36481, 55.14168 (WGS84)
Relative position This site represents three occurrences east of Blunt Mountain. The occurrences are in section 2, T. 78 S., R. 93 E., of the Copper River Meridian and section 35, T. 77 S., R. 93 E., of the Copper River Meridian. They range in elevation from about 300 feet to sealevel, and are about 1.3-1.5 miles from the highest point on Blunt Mountain. The coordinates are for the approximate center of the half-square-mile area that contains the occurrences. The site corresponds to loc. 3 in Berg (1972 [I 684]), loc. 143 in Elliott and others (1978), and loc. 29a-c 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
Silver Primary
Gold Primary
Copper Primary
Lead Primary
Zinc Primary

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Pyrite Ore
Sphalerite Ore
Quartz Gangue

Alteration

  • (Local) Local sericitization and iron-oxide alteration.

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Stratigraphic age (youngest) Late Permian
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite

Nearby scientific data

(1) -131.36481, 55.14168

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this site are recrystallized, Upper Triassic rhyolite, felsic tuff, and limestone (Berg, 1972). The rocks are folded and complexly faulted, and were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time.? the occurrences consist of sparsely mineralized, auriferous, sulfide-bearing quartz fissure veins in rhyolite that locally is sheared, sericitized, and impregnated with finely disseminated iron oxide. The veins are up to about 3 feet thick and contain sparse clots of pyrite and other sulfide minerals that, judging from sample assays, include galena, chalcopyrite, and sphalerite. Samples of variously mineralized quartz veins and country rocks contained up to 0.43 oz. Au/ton; 0.91 oz. Ag/ton, 2% Pb, 16.75% Zn, and 1.25% Cu (Berg, 1972, loc. 3; Karl, 1992, loc. 29).
  • Age = Probably Late Cretaceous or younger.

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 variously mineralized quartz veins and country rocks contained up to 0.43 oz. Au/ton; 0.91 oz. Ag/ton, 2% Pb, 16.75% Zn, and 1.25% Cu (Berg, 1972, loc. 3; Karl, 1992, loc. 29).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012384
USGS Alaska Resource Data File ARDF KC146

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 = Karl, 1992

General comments

Subject category Comment text
Deposit Model Name = Polymetallic veins (Cox and Singer, 1986; model 22c)

Reporter information

Type Date Name Affiliation Comment
Reporter 06-JUL-1999 H.C. Berg U.S. Geological Survey