Abstract:
The Pobei Cu-Ni deposit is located in the northeastern margin of Tarimcraton. The main ore types of this deposit contain speckled ore and sparse disseminated ore, which show gradual transition relationship. Sulfide ores show low ∑PGE content, which range from 2.47×10
-9 to 404.17×10
-9.The S has poor correlation with Ni, but has good positive correlation with Ir, Ru, Rh, Pt and Pd except few samples,which suggest that PGE were mainly occurred in the sufides. The Irshows significant positive correlation with Ru and Rh,but poor relationship with Pd.The Pd shows good positive correlation with Ru, Rh and Pt, which indicate that no obviousfractional crystallization of monosulfide solid solution(MSS) was occurred after the sulfide liquation. After normalizing to 100% sulfide, the average content of ∑PGE is 2 806.9×10
-9, the primitive mantle standardization diagram show left-oblique type of rich Pd and Pt, which are obviously depleted in PGE when compared with Ni and Cu. The simulated calculation shows that the "R" factors of the Pobei deposit are mainly range from 50 to 500, the content of Ru and Pd in parent magma are 0.36×10
-9 and 3.6×10
-9, respectively.A small amount of sulfide residual in the magma source is the main cause for the deficit of PGE.The silicate magma contained sulfide would consolidated into the rock and ore at stability dynamic environment, which were unfavourable for the effective accumulation sulfide, resulting the metal grade is low.