Geologic description
The Eb No. 4 prospect is hosted by the Fish Lake mafic-ultramafic complex, a lopolithic feeder of Late Triassic age of the Nikolai basalt flows (Nokleberg and others, 1991). The prospect lies in lower portion of the gabbroic unit of the second magmatic cycle of the Fish Lake ultramafic complex (W.T. Ellis, unpublished data, 1996). The prospect consists of float of sulfide-bearing coarse-grained pyroxenite; samples assay as much as 0.1 percent copper, 0.08 percent nickel, 140 parts per billion (ppb) palladium, and 85 ppb platinum. The metallic minerals are mainly pyrrhotite, along with chalcopyrite and pentlandite. The deposit does not crop out, but a good geophysical conductor is present that has been interpreted to be caused by sulfide accumulations (W.T. Ellis, unpublished data, 1996). Twelve hundred feet along strike a drill hole intersected 54 feet of pyroxenite grading 0.1 percent copper, 0.15 percent nickel, 198 ppb palladium, and 123 ppb platinum. This pyroxenite contained from 7 to 10 percent sulfides (W.T. Ellis, unpublished data, 1996). |
