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Washington

Prospect in Alaska, United States with commodity Copper
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Economic information about the deposit and operations
  12. Mining district
  13. Links to other databases
  14. Bibliographic references
  15. General comments
  16. Reporter information

Geologic information

Identification information

Deposit ID 10001606
MRDS ID A012370
Record type Site
Current site name Washington
Related records 10209905

Geographic coordinates

Geographic coordinates: -131.76288, 55.15085 (WGS84)
Relative position The Washington prospect is at an elevation of less than 100 feet, about 0.2 mile northwest of the southwest head of Dall Bay, and about 0.1 mile from tidewater. The site is in section 31, T. 77 S., R. 91 E., of the Copper River Meridian. It corresponds to loc. 127 in Elliott and others (1978), and to loc. 317 in Maas and others (1995). The location is accurate within 0.1 mile.

Site location context

Political divisions (FIPS codes)

Ketchikan Gateway(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ketchikan A-6(quadrangle 1:63,360 scale)

Ketchikan SW(quadrangle 1:100,000 scale)

Ketchikan(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Ketchikan(hydrologic unit)

Southern Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Tongass National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Jasper Gangue
Quartz Gangue

Alteration

  • (Local) Probably local silicification, carbonatization, pyritization, and introduction of hydrothermal hematite.

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 > Mafic Intrusive Rock > Diorite > Diabase

Nearby scientific data

(1) -131.76288, 55.15085
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this prospect consist of an assemblage of undivided Silurian or Ordovician metamorphosed bedded and intrusive rocks that are intruded by stocks and dikes of Silurian trondhjemite (Berg, 1973; Berg and others, 1988), the rocks are cut by a complex system of high-angle faults that mainly strike NE and NW. Locally, they also are permeated by finely disseminated hydrothermal hematite, giving them (especially the trondhjemite) a pink or red hue commonly mistaken for potassium feldspar. ? According to Elliott and others (1978), the deposit consists of a mineralized zone along a sheared and brecciated contact between diabase and pegmatite (hydrothermally altered trondhjemite?). Pyrite and chalcopyrite occur in the zone, accompanied by quartz and jasper gangue. The deposit was explored in the early 1900s by a 20-foot drift or adit (Brooks, 1902, p. 72; Maas and others, 1995, p. 229). Similarities in character and setting of the Washington deposit to those of other lodes in the Dall Bay area (see, for example, KC 131, 132) suggest that it is a polymetallic vein of Late Triassic or younger age.
  • Age = Late Triassic or younger.

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Mining district

District name Ketchikan

Comments on the workings information

  • Workings / Exploration = The deposit was explored in the early 1900s by a 20-foot drift or adit (Brooks, 1902, p. 72; Maas and others, 1995, p. 229).

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Elliott and others, 1978; Maas and others, 1995

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

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.