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Early Permian mafic-ultramafic complexes in eastern Xinjiang(新疆) are mainly dis-tributed in the Beishan(北山) area,Mid-Tianshan(天山) massif and Jueluotage(觉罗塔格) belt.Sys-tematic compositional mapping of olivines from these Early Permian mafic-ultramafic complexes demonstrates that an apparently spatial distribution and heterogeneous partial melting in the mantle source exists from the Beishan area,across the Mid-Tianshan massif,to the Jueluotage belt from the south to the north.This is probably consistent with the spatial evolutional differences and tectonic fea-tures of these three belts.The decreasing degree of partial melting,as revealed by decreasing Fo con-tents of olivines,from south to north and from east to west reflects the southward subduction of the Paleo-Asian Ocean and the south location of the indistinct mantle plume in the Permian.Simultane-ously,NiO and Fo-mapping in olivine also indicates that sulfide segregation before olivine crystalliza-tion played an important role in Ni-Cu mineralization in the mafic-ultramafic complexes.Olivines with the compositional range of Fo(77-86) and NiO(less than 0.22 wt.%) are more favorable for Ni-Cu sul-fide mineralization.
Early Permian mafic-ultramafic complexes in eastern Xinjiang (Xinjiang) are mainly dis-tributed in the Beishan area, Mid-Tianshan massif and Jueluotage belt.Sys-tematic compositional mapping of olivines from these Early Permian mafic-ultramafic complexes demonstrates that an apparently spatial distribution and heterogeneous partial melting in the mantle source exists from the Beishan area, across the Mid-Tianshan massif, to the Jueluotage belt from the south to the north. This is probably consistent with the spatial evolutional differences and tectonic fea- tures of these three belts. the decreasing degree of partial melting, as revealed by decreasing Fo con tents of olivines, from south to north and from east to west reflects the southward subduction of the Paleo-Asian Ocean and the south location of the indistinct mantle plume in the Permian.Simultane-ously, NiO and Fo-mapping in olivine also indicates that the sulfide segregation before olivine crystalliza tion an important role in Ni-Cu mineralization in the mafic-ultramafic complexes. Olivines with the compositional range of Fo (77-86) and NiO (less than 0.22 wt.%) are more favorable for Ni-Cu sul-fide mineralization.