The distribution of platinum-group elements in gabbros from Zhujiapu, Dabie orogen
大别造山带祝家铺辉长岩的铂族元素特征

The contents of platinum group elements ( PGEs: Ir, Ru, Rh, Pt, Pd) in Zhujiapu gabbros have been determined using ICP-MS after a nickel sulphide fire assay preconcentration. The absolute PGE abundances for all of the fourteen samples are extremely low. They display pronounced positively-sloping in mantle-normalized pattern that highlight their slightly depleted in PPGEs and strongly depleted in IPGEs. Pd/Ir ratios (22-138) are higher than that of primitive mantle. These characters suggest the fractionation of PGE in the gabbros of Zhujiapu. Sulphide segregation has happened in the original magma. S-saturation of the magma can be promoted by crust contamination. PCE fractionation in the gabbros is controlled by the phase that can potentially fractionate IPGEs is spinel,sometimes maybe Os-Ir alloy,but the PPGEs reside in sulfide.