Casey Glacier Sphalerite

Occurrence in Alaska, United States with commodities Lead, Zinc, Silver, Gold, Copper

Geologic information

Identification information

Deposit ID 10308519
Record type Site
Current site name Casey Glacier Sphalerite

Geographic coordinates

Geographic coordinates: -130.20476, 56.05177 (WGS84)
Relative position The Casey Glacier Sphalerite occurrence consists of mineralized boulders of float scattered in an area of about a quarter of a square mile (Maas, 1995, p. 233, 235). The occurrence is in the northeast corner of Section 23 between elevations of about 3500 and 4100 feet, on a north-facing mountainside south of the West Fork of Texas Creek. It is about 2.0 miles east of Texas Lake. The above coordinates are for the approximate center of the area of float boulders. The location is accurate to within about a quarter of a mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Lead Primary
Zinc Primary
Silver Secondary
Gold Secondary
Copper Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Pyrite Ore
Sphalerite Ore
Calcite Gangue
Quartz Gangue

Alteration

  • Intense silica and carbonate alteration of brecciated andesite hostrock.

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Nearby scientific data

(1) -130.20476, 56.05177

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this occurrence are pelitic metasedimentary and subordinate andesitic metavolcanic strata of the Jurassic or older Mesozoic Hazelton Group, which is underlain and locally intruded by the Triassic Texas Creek Granodiorite; and the Eocene Hyder Quartz Monzonite, which intrudes the Hazelton and Texas Creek rocks (Smith, 1977; Koch, 1996). Maas and others (1995, p. 235, 246) describe the occurrence as mineralized float boulders of brecciated Hazelton andesite containing massive bands and veinlets of sphalerite, galena, and minor(?) pyrite and chalcopyrite. The sulfides carry silver and a trace of gold. Intense silica and carbonate alteration has accompanied brecciation and mineralization. Lead-isotope studies of galena from this occurrence (Maas and others, p. 235) indicate that the mineralization is Jurassic in age, contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993).
  • Age = Lead-isotope studies of galena from this occurrence (Maas and others, 1995, p. 235) indicate that the mineralization is Jurassic in age, contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993).

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Mining district

District name Hyder

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF BC085

Bibliographic references

  • Deposit

    Smith, J.G., 1977, Geology of the Ketchikan D-1 and Bradfield Canal A-1 quadrangles, Alaska: U.S. Geological Survey Bulletin 1425, 49 p.

  • Deposit

    Alldrick, D.J., 1993, Geology and metallogeny of the Stewart mining camp, northwestern British Columbia: British Columbia Department of Mines and Petroleum Resources Bulletin 85, 105 p., 2 plates.

  • Deposit

    Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.

  • Deposit

    Koch, R.D., 1996, Reconnaissance geologic map of the Bradfield Canal quadrangle, southeastern Alaska: U.S. Geological Survey Open-File Report 81-728-A, 35 p., 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Maas and others, 1995

General comments

Subject category Comment text
Deposit Model Name = Polymetallic veins
Deposit Other Comments = Although no outcrop of the banded sulfides was found, the location of the boulder rubblecrop suggests that their source is beneath the icefield at the summit between Ferguson and Casey Glaciers (Maas, 1995, p. 235).

Reporter information

Type Date Name Affiliation Comment
Reporter 17-MAY-1998 H. C. Berg U.S. Geological Survey