The origin of Pd in pentlandites from Creighton mine, Ni-Cu-PGE deposit, Sudbury, Canada

摘要

It is necessary to determine which mineral phases host the Platinum-Group Elements (PGE) in order to: a) efficiently extract the PGE and b) better understand the petrogenesis of the ores. Laser Ablation-ICP-MS has been used to determine the in situ PGE content of base metal sulfides (BMS) from PGE-reefs (e.g. Barnes et al. 2008). These studies have shown that: ① the concentration of IPGE (Os, Ir, Ru and Rh) in pyrrhotite and pentlandite is consistent with their formation from monosulfide solid solution (mss). ② pentlandite is a major carrier for Pd and ③ Pt and Au are not present in BMS. If pentlandite formed by exsolution from mss then it is not clear why it contains most of the Pd. This is because Pd is expected to concentrate into the Cu-rich liquid during mss fractional crystallization.