Unnamed (northeast side of Willoughby Island)

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

Geologic information

Identification information

Deposit ID 10002277
MRDS ID A013181
Record type Site
Current site name Unnamed (northeast side of Willoughby Island)
Related records 10233543

Geographic coordinates

Geographic coordinates: -136.13208, 58.59973 (WGS84)
Relative position The deposit is reported to be on the northeast side of Willoughby Island at an elevation of 450 feet. It is assumed to be about 0.5 mile southwest of Johnson Cove. Accuracy is uncertain. The site is about the same as locality 49 in Cobb (1972) and locality 95 in Kimball and others (1978). The deposit was not found by the U.S. Geological Survey in 1966 (MacKevett and others, 1971).

Site location context

Political divisions (FIPS codes)

Hoonah-Angoon(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Mount Fairweather C-1(quadrangle 1:63,360 scale)

Juneau NW(quadrangle 1:100,000 scale)

Mount Fairweather(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Glacier Bay(hydrologic unit)

Northern Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Glacier Bay National Park(National Park)

National Park NPS(Type of land area)

NPS(Federal land areas administered by NPS)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Arsenic Critical Secondary
Cobalt Critical Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Lollingite Ore
Calcite Gangue

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone

Nearby scientific data

(1) -136.13208, 58.59973

Economic information

Comments on the geologic information

  • Geologic Description = The northeastern part of Willoughby Island is underlain by massive and bedded limestone of Devonian and Silurian age, part of a major reefoid mass (Brew and others, 1978). Locally the marble is cut by mafic dikes of Late Cretaceous or Tertiary age. At this prospect, pyrite, loellingite (?) and chalcopyrite form massive replacement layers or lenses in marble. One such massive sulfide deposit was described as 5-feet-thick and traceable on strike for 15 feet (Reed, 1938). At least three other similar occurrences were reported nearby by Reed.
  • Age = Late Cretaceous or younger.

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Juneau

Comments on the workings information

  • Workings / Exploration = The deposit has not been found since Reed's visit in the 1930s (Reed, 1938). Workings are unknown, but there probably were shallow pits and trenches on the eight claims staked on the deposit before 1902.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Reed, 1938

General comments

Subject category Comment text
Deposit Model Name = Massive sulfide replacement in marble. Distal deposit related to subjacent intrusive; deposits formed after late emplacement of mafic dikes.
Deposit Other Comments = the deposit is in marble of Devonian and Silurian age; mineralization followed emplacement of mafic dikes of probable Late Cretaceous or Tertiary age. ? the site is in Glacier Bay National Park and Preserve.

Reporter information

Type Date Name Affiliation Comment
Reporter 14-APR-99 Hawley, C.C. Hawley Resource Group

Beyond USGS

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

Authoritative Alaska resources

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