Ore Genesis of Ore Body ^#1 of the Jinchuan Ni-Cu Sulfide Deposit

The Jinchuan Ni-Cu-(PGE) sulfide deposit is hosted by ultramafic intrusions in northwestern China.It is the third-largest Ni deposit in the world.The central part of the Jinchuan intrusion(Ore Body 1) has a "tongue-like" shape in cross section and hosts～56.8% of the known Ni resources.It is characterized by concentrically zoned,with net-textured ore surrounded by disseminated sulfide.Net-textured ore is dominant over other ore types in ore body ^#1.Based on 100% sulfide recalculation,different types of ore in ore body ^#1 have high and low value characteristics of IPGE,and Pt vary largely,Pt/(Pt+Pd) ratios of most samples are out of (0.3-0.7).The Ni,Cu content variations of drill hole samples indicate that Cu-rich ores concentrated at base of net-texture ore body,and content of this two elements appears obvious negative relationships,Ni/Cu ratios vary largely in deep.This research reveals that the ore body ^#1 was affected obviously by hydrothermal alteration.IPGE and small scale variations of Ni/Cu ratios are likely due to fractional crystallization of MSS.Small Cu-PPGE rich lenses and large scale variations of Ni/Cu in the deep part of ore body ^#1 may be the result of MSS fractionation or hydrothermal alteration.