Trace element geochemistry of andesites associated with massive sulfide deposits in Noranda, Quebec

grantor: University of TorontoStudies on seafloor hydrothermal sulfide mineralization on at Southern Explorer Ridge in the NE Pacific (Michael et al., 1989; Scott et al., 1990; Constantin and Scott, 1994) have established a link between the presence of hydrothermal activity and the trace element composition of basaltic rocks. These studies have shown that the trace element signature of tholelitic basalts varies along the ridge axis with the enrichment of large Ion lithophile elements and increase in the Zr/Nb ratio near the, topographic high where sulfides are typically found. A similar variation is observed in the trace element composition of Archean andesites associated with Cu-Zn massive sulfide ores at Noranda, Quebec. The present study was carried out on two volcanic units the Amulet Andesite Formation and Flavrian Andesite Formation, which constitute part of the ore-hosting Mine Sequence. The association of massive sulfide deposits with the most enriched parts of the mafic volcanic sequences, as observed in the Noranda. camp, suggests possible lithogeochemical vectors pointing towards the hydrothermal vents. (Abstract shortened by UMI.)M.Sc