Geochemical characteristics of the platinum-group elements in the Abulangdang ultramafic intrusion, Sichuan Province, China

The contents of the platinum-group elements (PGEs: Os, Ir, Ru, Rh, Pt, Pd) in the Abulangdang ultramafic intrusion have been determined using ICP-MS after nickel sulfide fire assay preconcentration. Different samples show significant differences in absolute PGE abundance. They display a pronounced negative incline in mantle-normalized patterns which are characterized by strong enrichment in IPGEs (Os, Ir, Ru) and depleting to slight enrichment in PPGEs (Rh, Pt, Pd). The characteristics of PGE distribution in the Abulangdang rocks are due to the combined action of sulfide and non-sulfide (spinel/chromite or alloy or micro-granular aggregation of metals). In comparison with the mafic-ultramafic rocks which host Ni-Cu-PGE deposits in the Emeishan Large Igneous Province (ELIP), it is assumed that the Abulangdang ultramafic intrusion may be the product of early-stage magma activity in the ELIP. © Science Press, Institute of Geochemistry, CAS and Springer-Verlag GmbH 2009.