The area of the showings is primarily underlain by Mesozoic Skeena Group rocks consisting of basaltic lava flows, tuff breccia, flow-banded rhyolite, chert and argillite. Rhyolite dikes and sills in the area have been dated (K-Ar 76.5 plus or minus 3.0 million years) as Upper Cretaceous. The Skeena Group rocks are intruded by an Eocene Nanika Intrusion comprised of quartz monzonite and por- phyritic monzonite.
One type of mineralization is hosted by a quartz filled shear zone with a width of approximately 3 metres that occurs in a sheared and sericitized rhyolite with patchy azurite staining. The minera- lization consists of chalcopyrite, pyrite, stibnite, galena and sphalerite with secondary chalcocite, malachite, azurite, limonite and manganese oxides. A small amount of molybdenite has also been reported in the vein. Values up to at least 233.14 grams per tonne silver and 2.06 grams per tonne gold have been obtained. In 1929, a 3.0 metre sample across the shear assayed 233.14 grams per tonne silver and 0.9 per cent copper (Minister of Mines Annual Report 1929, page 175).
The other type of mineralization occurs over widths of 12 to 15 metres in a tuff breccia consisting locally of rhyolitic breccia fragments in an andesitic matrix. Pyrrhotite, chalcopyrite, sphal- erite, and pyrite have selectively replaced the matrix and penetrated cracks in the coarse fragments. In 1929, a sample across 13.7 metres assayed 20.57 grams per tonne silver and 0.4 per cent copper (Minister of Mines Annual Report 1929, page 175). A recent minera- lized grab sample from the same area assayed 13.7 grams per tonne silver, 0.26 per cent copper, 0.12 per cent zinc, 10.72 per cent iron and 0.016 per cent nickel (Geology, Exploration and Mining 1970, page 147). Also, similar mineralization is visible in trenches and pits several metres to the north and east of the main showing. A company report quotes seven assays on grab samples from this area averaging 30.86 grams per tonne silver and 0.18 per cent copper (Geology, Exploration and Mining 1970, page 147).
