Geologic descriptionThe prospect consists of a 4-foot- by 20-foot open cut exposing interbedded graywacke and slate that contains a silicified, sulfide-bearing zone (Kurtak and Jeske, 1986). The slate and graywacke unit is roughly 300 by 1,000 feet and is enclosed by greenstone; both units are mapped as Orca Group of early Tertiary age (Nelson and others, 1985). The siliceous sulfide-bearing zone varies from 6 inches to 3 feet wide and contains from 5 to 30 percent sulfide minerals. These minerals consist of pyrite, chalcopyrite, and some covellite (Kurtak and Jeske, 1986). Samples from the open cut contained from 25 ppm to 3.8 percent copper and from 0.2 to 28 ppm silver (Kurtak and Jeske, 1986). |
Geologic map unit |
(-147.734837561673, 60.3294264827469) |
Mineral deposit model |
Besshi massive sulfide (Cox and Singer, 1986; model 24b) |
Mineral deposit model number |
24b |
Age of mineralization |
Tertiary or younger; the mineralization is in rocks of the Orca Group of Tertiary age. |
Alteration of deposit |
The mineralization is in silicified slate, but no details about the alteration are given (Kurtak and Jeske, 1986). |