Geologic description
The Talkeetna prospect consists of: 1) greenstone with replacement bodies of specular hematite and quartz; 2) greenstone breccia with clasts that are partially replaced by pyrite and chalcopyrite in a matrix that contains hematite, chalcopyrite, and quartz; and 3) an east-west shear zone with quartz veinlets that contain pyrite, chalcopyrite, and hematite (Capps, 1919 [B 692]). Amygdules in the greenstone are filled with epidote. Mineralization parallels the shear zone which is up to 30 feet thick and at least several hundred feet long. A conspicuous gossan contains copper carbonates (Capps, 1919 [B 692]). Capps reported samples that contain up to 8 percent copper. Csejtey and Miller (1978) collected float samples that contain small amounts of gold. U.S. Bureau of Mines grab samples contain up to 85,000 parts per million copper and 9.6 parts per million silver; 5-foot chip samples contain up to 25,000 parts per million copper and 5.4 parts per million silver (Fechner, 1986). A number of open cuts and trenches have been excavated through the gossan. As of January 1, 2000, Cominco held a block of approximately 25 state claims covering this and adjacent prospects (Northern Associates Inc., written communication, 2001). |