Birdseye

Prospect in Alaska, United States with commodities Gold, Lead, Zinc

Geologic information

Identification information

Deposit ID 10001579
MRDS ID A012332
Record type Site
Current site name Birdseye
Related records 10233871

Geographic coordinates

Geographic coordinates: -131.56566, 55.30585 (WGS84)
Relative position The Birdseye prospect is on the Tongass Narrows shoreline of Revillagigedo Island, about 4 miles southeast of Ketchikan and 1.3 miles northwest of Mountain Point. The site is in section 3, T. 76 S., R. 91 E., of the Copper River Meridian. It corresponds to loc. 73 in Elliott and others (1978). The location is accurate within about 0.1 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Lead Secondary
Zinc Secondary

Materials information

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

Alteration

  • (Local) The wallrock adjacent to the veins is impregnated with sulfides.

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

Nearby scientific data

(1) -131.56566, 55.30585

Comments on the geologic information

  • Geologic Description = The country rocks in this part of Revillagigedo Island are mainly marine, andesitic or basaltic metavolcanic rocks and interbedded pelitic sedimentary rocks that are intruded by Cretaceous stocks, sills, and dikes of feldspar-porphyritic granodiorite, and by a stock and probably related plugs of Tertiary gabbro (Berg and others, 1988). The strata and some of the granodiorite were regionally metamorphosed to greenschist grade in Late Cretaceous time. These rocks subsequently were contact metamorphosed to hornblende hornfels: locally, near some of the Cretaceous granodiorite contacts, and, more widely, peripheral to the Tertiary gabbro. The premetamorphic age of the strata is uncertain. Berg and others (1988) note that they closely resemble Upper Jurassic to mid-Cretaceous flysch and volcanic rocks nearby on Gravina Island. The country rocks are cut by a high-angle fault along Tongass Narrows that displays about 4 miles of right-lateral offset.? the deposit consists of pyrite-bearing quartz fissure veins or lenses, 3-5 feet wide, in a porphyry dike/sill intruded parallel to the composition layering of slate and schist, which strike NW and dip 45 NE (Brooks, 1902, p. 62; Wright and Wright, 1908, p. 152. The dike/sill is 10-20 feet thick, contains many inclusions of black slate, and adjacent to the veins is impregnated with sulfide minerals. The ore minerals in the vein are pyrite, galena, sphalerite, and free gold. Pyrite-bearing quartz veins also occur in the slate and schist country rocks. These veins predate the porphyry dike and do not carry gold.? the prospect, one of the first discovered in the Ketchikan area, was explored in the early 1900s by surface stripping and a 32-foot-deep shaft. A small amount of gold probably was recovered, but there is no public record of any production.
  • Age = Cretaceous or younger.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Mining district

District name Ketchikan

Comments on the production information

  • Production Notes = A small amount of gold probably was recovered in the early 1900s, but there is no public record of any production.

Comments on the workings information

  • Workings / Exploration = The Birdseye deposit, one of the first discovered in the Ketchikan area, was explored in the early 1900s by surface stripping and a 32-foot-deep shaft.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012332
USGS Alaska Resource Data File ARDF KC076

Bibliographic references

  • Deposit

    Brooks, A.H., 1902, Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska: U.S. Geological Survey Professional Paper 1, 120 p.

  • Deposit

    Wright, F.E., and Wright, C.W., 1908, The Ketchikan and Wrangell mining districts, Alaska: U.S. Geological Survey Bulletin 347, 210 p.

  • 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

    Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map MF-1807,27 p., scale 1:250,000.

Comments on the references

  • Primary Reference = Wright and Wright, 1908

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