Unnamed (west side of Casement Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Zn
Other commodities Ba
Ore minerals barite; pyrite
Gangue minerals ankerite; quartz

Geographic location

Quadrangle map, 1:250,000-scale JU
Quadrangle map, 1:63,360-scale D-6
Latitude 58.9715
Longitude -135.9875
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 1,000 feet, approximately 3 miles west of Snow Dome and 7 miles north of Adams Inlet. It is on a nunatak on the west side of lower Casement Glacier in the NE1/4 section 36, T.33 S., R.56 E. of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description

This occurrence consists of an iron-stained altered zone that is exposed on a small nunatak of thin-bedded limestone, argillite, and hornfels. The altered zone is about 30 feet thick and contains several quartz-ankerite-barite veins that are less than 1 foot thick. The veins and the altered zone strike N 58 W and dip vertically. Pyrite is the only visible sulfide mineral in either the veins or the altered zone. A select sample contained 300 ppm zinc (MacKevett and others, 1971).
The area is underlain by deformed and metamorphosed Silurian or Devonian carbonate, clastic and volcanic clastic rocks that have been intruded by Upper Jurassic and Lower Cretaceous granitic and dioritic rocks (Brew and others, 1992). The rocks immediately west of this occurrence are metamorphosed Silurian and Devonian graywacke and argillite that have been intruded by foliated Cretaceous granitic rocks (Brew and others, 1978).
Geologic map unit (-135.989385384594, 58.971108824119)
Mineral deposit model Possible polymetallic replacement deposit (Cox and Singer, 1986; model 19a)
Mineral deposit model number 19a
Alteration of deposit Iron staining is reported (MacKevett and others, 1971).

Production and reserves

Workings or exploration Only limited surface sampling.
Indication of production None