Unnamed (east of Crater Lake)

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

Geologic information

Identification information

Deposit ID 10001630
MRDS ID A012394
Record type Site
Current site name Unnamed (east of Crater Lake)

Geographic coordinates

Geographic coordinates: -131.35369, 55.0578 (WGS84)
Relative position This site represents three occurrences along a 0.3 mile stretch of the southeast shoreline of Annette Island, about 0.7 mile east of Crater Lake. The occurrences are in section 35, T. 78 S., R. 93 E., of the Copper River Meridian. The coordinates are for the approximate center of this group of occurrences. The site corresponds to loc. 7 in Berg (1972 [I 684]), loc. 153 in Elliott and others (1978), and loc. 39a-c in Karl (1992). The location is accurate within 0.1 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Gold Secondary
Lead Secondary

Materials information

Materials Type of material
Bornite Ore
Chalcopyrite Ore
Malachite Ore
Pyrite Ore
Calcite Gangue
Hematite Gangue
Quartz Gangue

Alteration

  • (Local) Local iron staining. Hydrothermal alteration (sericite, hematite) of country rocks.

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 Host
    Rock type Plutonic Rock > Granitoid > Quartz Monzonite
    Rock unit name Annette Pluton;Annette Pluton
    Rock description Annette Pluton;Annette Pluton

Nearby scientific data

(1) -131.35369, 55.0578

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this site include undivided, metamorphosed Silurian and Ordovician volcanic, sedimentary, and intrusive rocks; and Silurian felsic granitic rocks that intrude the undivided assemblage (Berg, 1972). The rocks were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time, and are intensely sheared, sericitized, and locally permeated with hydrothermal hematite.? the occurrences consist of sparse sulfide pods and sulfide-bearing quartz-calcite veins in the sheared granitic rock (Berg, 1972, loc. 7; Karl, 1992, loc. 39). The metalliferous minerals occur in iron-stained zones an inch or so wide and about a foot long. Sulfides include pyrite, chalcopyrite, and traces of bornite; some of the occurrences contain a little malachite, and the sheared rocks locally contain finely disseminated hematite.? Samples of sulfide-bearing granitic rock and of a pyritic quartz vein contained up to 0.41 ppm Au, 20 ppm Ag, and 2% Cu; a sample of a pyrite- and bornite-bearing quartz-calcite vein contained 0.07 ppm Au, 7 ppm Ag, 1% Cu, and 100 ppm Pb (Karl, 1992, loc. 39a-c).

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 sulfide-bearing granitic rock and of a pyritic quartz vein contained up to 0.41 ppm Au, 20 ppm Ag, and 2% Cu; a sample of a pyrite- and bornite-bearing quartz-calcite vein contained 0.07 ppm Au, 7 ppm Ag, 1% Cu, and 100 ppm Pb (Karl, 1992, loc. 39a-c).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012394
USGS Alaska Resource Data File ARDF KC157

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