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Unnamed (near mouth of creek draining Leduc Lake)

Occurrence in Alaska, United States with commodities Copper, Silver, Molybdenum, Lead, Zinc
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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 10001547
MRDS ID A012294
Record type Site
Current site name Unnamed (near mouth of creek draining Leduc Lake)

Geographic coordinates

Geographic coordinates: -130.81677, 55.92865 (WGS84)
Relative position This occurrence is at an elevation of about 100 feet in the canyon walls of the stream draining Leduc Lake, just before the stream enters Leduc River, 2 miles above its confluence with Chickamin River. The site is in section 36, T. 68 S., R. 94 E., of the Copper River Meridian. It corresponds to loc. 17 in Elliott and others (1978). The location is accurate within about 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 D-3(quadrangle 1:63,360 scale)

Ketchikan NW(quadrangle 1:100,000 scale)

Ketchikan(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Southern Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Misty Fiords National Monument Wilderness(Wilderness)

Wilderness FS(Type of land area)

FS(Federal land areas administered by FS)

Tongass National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Misty Fjords National Monument Wilderness(Wilderness)

Wilderness FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Molybdenum Secondary
Lead Secondary
Zinc Critical Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrrhotite Ore

Alteration

  • (Local) Locally conspicuous iron-staining.

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Gneiss

Nearby scientific data

(1) -130.81677, 55.92865
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this occurrence are pelitic paragneiss, subordinate quartzofeldspathic paragneiss, and minor marble. These metamorphic rocks form roof pendants, screens, and inclusions in Tertiary or Cretaceous foliated granodiorite and quartz diorite of the Coast Range batholith (Berg and others, 1977, p. 124-126; Berg and others, 1988). The metamorphic rocks probably represent marine argillaceous, clastic, and minor carbonate strata that underwent high-grade regional metamorphism in Cretaceous or Tertiary time. The premetamorphic age of the strata is uncertain, but they probably are mainly Paleozoic and may be as old as Precambrian (Berg and others, 1988, p. 26; Gehrels and others, 1990; Crawford and others, in press).? the occurrence is a poorly-exposed, rusty-weathering zone in paragneiss about 900-1800 feet wide and 2.5 miles long (Berg and others, 1977, area M-2, p. 124-126). Some of the rocks contain a little pyrrhotite and traces of chalcopyrite. Four chip samples of the accessible part of the zone, representing two separate horizons totalling about 200 feet thick, contained 30-160 ppm Cu, 10-90 ppm Pb, 80-400 ppm Zn, 5-50 ppm Mo, and 0.5-2.0 ppm Ag. A six-foot-thick layer of graphitic marble contained negligible amounts of these metals.

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 = Four chip samples of the accessible part of the iron-stained zone, representing two separate horizons totalling about 200 feet thick, yielded values of 30-160 ppm Cu, 10-90 ppm Pb, 80-400 ppm Zn, 5-50 ppm Mo, and 0.5-2.0 ppm Ag (Berg and others, 1977, p. 124-126). A six-foot-thick layer of graphitic marble contained negligible amounts of these metals.

Reference information

Comments on the references

  • Primary Reference = Berg and others, 1977

General comments

Subject category Comment text
Deposit Model Name = Disseminated base-metal sulfides in metamorphic roof pendant
Deposit Other Comments = Site is in Misty Fiords National Monument Wilderness.

Reporter information

Type Date Name Affiliation Comment
Reporter 29-JUN-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.