Unnamed (in the northern Chilkat Range)

Occurrence in Alaska, United States with commodities Silver, Copper, Cobalt

Geologic information

Identification information

Deposit ID 10308239
Record type Site
Current site name Unnamed (in the northern Chilkat Range)

Geographic coordinates

Geographic coordinates: -135.7221, 59.14974 (WGS84)
Relative position This occurrence is at an elevation of about 5,000 feet about 3.7 miles, S87W from triangulation station 'Bow' on the west side of Chilkat Inlet. It is in the SW1/4, section 25, T. 31 S., R. 58 E. of the Copper River Meridian and is in a narrow septum of rock between two unnamed ice fields. The location corresponds to location 68 of Gilbert (1988).
(click for info)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Copper Primary
Cobalt Secondary

Materials information

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

Alteration

  • (Local) Skarn.

Mineral occurrence model information

Model code 59
USGS model code 18b
Deposit model name Skarn Cu
Mark3 model number 8

Nearby scientific data

(1) -135.7221, 59.14974

Comments on the geologic information

  • Geologic Description = Gilbert (1988) collected four rock samples described as, 'skarn with pyrrhotite (60%) and chalcopyrite', 'gossan with pyrrhotite', 'black schist with pyrrhotite (20%)', and 'quartz with pyrite in shear'. The samples contain up to 4.6 ppm silver, 5,950 ppm copper, and 95 ppm cobalt. The host rocks are mafic Paleozoic metavolcanics and metasediments that include argillaceous marble. Cretaceous medium-grained hornblende diorite and foliated granodiorite are nearby (Gilbert, 1988). The mineralization is probably the same age as the nearby Cretaceous intrusive rocks.
  • Age = the age is inferred to be Cretaceous based upon the Cretaceous age of nearby intrusive rocks (Gilbert, 1988).

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Probably inactive

Mining district

District name Juneau (Skagway subdistrict)

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF SK009

Bibliographic references

  • Deposit

    Gilbert, W.G., 1988, Preliminary geology and geochemistry of the north Chilkat Range: Alaska Division of Geological and Geophysical Surveys Report of Investigations 88-8, 2 sheets, scale 1:36,200.

Comments on the references

  • Primary Reference = Gilbert, 1988

General comments

Subject category Comment text
Deposit Model Name = Copper skarn? (Cox and Singer, 1986: model 18b?)

Reporter information

Type Date Name Affiliation Comment
Reporter 04-FEB-01 T.C. Crafford T. Crafford & Associates