Contrasting Pd-bearing phases from the mineralized zones of the Lac-des-Iles-Complex (Ontario, Canada)

We have analyzed the base metal sulfide (BMS) assemblages in relation to silicate minerals present in rocks from mineralized zones of the Lac-des-Iles-Complex (LDIC). We found that the texture and mineralogy of BMS evolve with those of silicates according to the degree of alteration. In addition, in situ analysis of chalcophile elements in BMS combined with mass balance calculations show that pentlandite controls 30% of whole-rock Pd, the rest is present as platinum group minerals (PGM). There is no evidence to indicate a relationship between the enrichment of Pd and alteration of the BMS, particularly in the High-grade Zone. It is suggested that at low temperature (~ 450°C), a fluid rich in Pd, Bi, Sb and As was introduced into the High-grade Zone and Pd precipitated in the form of PGM, such as Pd-Bi-Te, Pd-Sb-As, Pd-As, Pd-S and Pd-Te