Constraints on ore vectoring from geochemical fingerprints of porphyry style pyrite

Abstract

Abstract The sulfur isotope compositions of three generations of pyrite originated from skarns, stockwork, and late-stage, post-hydrothermal veins from three various zones of the porphyry style Myszków Mo–Cu–W deposit (center, circum-deposit, and periphery) were investigated as a proxy for the mineralized core of porphyry system. Overall, the mode of δ34Spyrite decreases with time, from skarn- through main- up to late-stage of ore mineralization (with average values of + 6.13, + 5.65, and + 3.34 ‰, respectively). The gradual decrease in δ34S values outwards from the deposit core (av. 3.95 ‰), through circum-deposit (av. + 3.40‰) to distal zone (av. + 3.05 ‰) was detected only for late-stage pyrite. Both the temporal and lateral zonation of δ34Spyrite could be explained by the progressive temperature decrease of the mineralized system and the mixing of ore-forming solutions with more dilute meteoric waters. The trace geochemistry of late-stage pyrite shows relatively constant values of Tl (from 0.13 to 0.14 ppm), Ti (9.10–10.30 ppm), Cr (9.94–12.37 ppm), and Mn (6.94–7.59 ppm) regardless of the zone of the Myszków Mo–Cu–W deposit. While, As (24.96–184.80 ppm), Sb (0.50–13.52 ppm), Bi (0.57–1.54 ppm) in pyrite and Sb/Te (0.06–1.62), Co/Bi (3.32–34.23), and Ag/Ni (0.006–0.140) increase with the proximity to the ore, contrary to Ag/Co which rises towards the periphery of the deposit (0.04–0.13). Ultimately, these results indicate that sulfur isotope data supported by trace geochemistry of late-stage pyrite can be potentially used as vectoring proxies to predict the likely direction to the mineralized center of a porphyry system.