Jensen

Prospect, Inactive

Alternative names

Glacier Island
Portsmouth
Scotia Bell

Commodities and mineralogy

Main commodities Ag; Au; Cu
Ore minerals chalcopyrite; pyrite
Gangue minerals epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale D-1
Latitude 60.8886
Longitude -147.0802
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is located on the east side of Glacier Island about a mile south of Finski Point. It is in the W1/2 section 30, T. 11 S., R. 10 W., of the Copper River Meridian. This is location 189 of Tysdal (1978 [MF-880-A]) and location S-108 of Jansons and others (1984). This location is accurate to within half a mile.

Geologic setting

Geologic description

The prospect consists of several showings of shattered Orca Group (of Tertiary age) greenstone cemented by quartz and epidote containing pyrite and chalcopyrite in what appears to be a single shear zone in a pronounced gully. The shear zone strikes N5W and dips 65W (Cobb and Tysdal, 1980). The shear zone averages 4 feet in width; most of the mineralized portion is from 5 to 12 inches wide. One body of solid cupiferous pyrite in the zone is 10 feet wide and of unknown length. Another mineralized zone consists of a streak of solid chalcopyrite along the hanging wall of the shear. This zone is 3 inches thick; its length is unknown (Tuck, 1933).
Geologic map unit (-147.082241206846, 60.888059752026)
Mineral deposit model Besshi massive sulfide (Cox and Singer, 1986; model 24b)
Mineral deposit model number 24b
Age of mineralization Tertiary or younger; the veins cut Orca Group rocks of Tertiary age.
Alteration of deposit Basalt altered to greenstone.

Production and reserves

Workings or exploration There are three adits on the prospect. Two are located at 250 feet and one at 500 feet elevation. One of the lower adits has 225 feet of workings, and the other has 30 feet of workings. The upper adit is 30 feet long. There is also some surface trenching . Assays show traces of gold and silver (Tuck, 1933).
Indication of production None

Additional comments

There are considerable workings on this prospect, considering there has been no production.

References

MRDS Number A010416

References

Reporters Jeff A. Huber (Anchorage)
Last report date 3/9/2000