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  3. Mineral Resource Data System (MRDS)

Unnamed (head of Purple Lake)

Occurrence 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. Host and associated rocks
  9. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. General comments
  15. Reporter information

Geologic information

Identification information

Deposit ID 10001625
MRDS ID A012389
Record type Site
Current site name Unnamed (head of Purple Lake)

Geographic coordinates

Geographic coordinates: -131.44064, 55.1078 (WGS84)
Relative position This occurrence is on the north shore of an unnamed small lake that drains into the head of Purple Lake. The site is in section 17, T. 78 S., R. 93 E., of the Copper River Meridian. It corresponds to loc. 23 in Berg (1972 [I 684]), loc. 147 in Elliott and others (1978), and loc. 42 in Karl (1992). The location is accurate within 0.1 mile.

Site location context

Political divisions (FIPS codes)

Prince of Wales-Hyder(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ketchikan A-5(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

Annette Island Indian Reservation(American Indian Reservation)

American Indian Reservation BIA(Type of land area)

BIA(Federal land areas administered by BIA)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary

Materials information

Materials Type of material
Chalcopyrite Ore

Alteration

  • (Local) Local sericitization of trondhjemite hostrock.

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granite
    Rock unit name Annette Pluton
    Rock description Annette Pluton
    Stratigraphic age (youngest) Late Silurian
    Stratigraphic age (youngest) Late Silurian
  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Granite

Nearby scientific data

(1) -131.44064, 55.1078
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The country rock in the area of this site is Silurian trondhjemite (Berg, 1972). Locally, the trondhjemite is sheared and sericitized, probably owing to Late Cretaceous greenschist-grade regional metamorphism. The occurrence consists of small amounts of chalcopyrite disseminated in the trondhjemite.

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Mining district

District name Ketchikan

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Karl, 1992

General comments

Subject category Comment text
Deposit Model Name = Disseminated Cu deposit of undetermined origin.

Reporter information

Type Date Name Affiliation Comment
Reporter 06-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.