Eric Alfreds Albrechtsons HBSc thesis abstract

Sheared, steeply dipping volcanic rocks of the Triassic Nicola Group are found on the west side of the Thompson River.  Mapping of the 11 square kilometer Silica claim group located southwest of the town of Ashcroft, B.C., has revealed a sequence of intermediate and porphyritic felsic rocks.  This assemblage has been intruded by quartz diorite stocks, thought to be associated with the Guichon Creek batholith.  Petrographic and limited geochemical work has been done in order to better describe the observed rock units.  These studies imply that most of the siliceous, pyritic, quartz-feldspar porphyritic rocks have the magmatic characteristics of rhyolite flows, and may not be "silicified greenstones" or crystal tuffs as previously described.  Associated minor copper mineralization is seen both as co-precipitated chalcopyrite in pyrite hosted in small podiform masses of chlorite schist, and as malchite in quartz veins.  Despite the presence of the Guichon Creek batholith, the sulfide occurrences do not appear to be of porphyry-type mineralization; these may be indicative of volcanogenic sulfide concentrations located down dip or along strike of the sheared strata.