Geological Characteristics and Prospecting Potential of Magmatic Ni-Cu Sulfide Deposits in Northwest China

Northwest China is the most developed area of magmatic Ni-Cu sulfide deposits in China. There are mainly three important metallogenic periods. The geological characteristics, mineralization condition and formation indicators of these three periods are obviously different. This paper summarizes the current researches on the magmatic Ni-Cu sulfide deposits. On the basis of field investigation, the authors found that the tectonic background for the formation of giant or super-large magmatic Ni-Cu sulfide deposits is the continental rifts. Only the ferruginous ultramafic intrusion has the potential to be an economically-valuable deposit. The deep and large cut-through crust faults provide favorable conditions for the upwelling of mantle magma. The well-differentiated ultramafic-ultramafic complex has the potential to hold the Ni-Cu ore. Crystal differentiation promotes sulfide saturation, and crustal sulfur contamination is the key to mineralization. The complex of olivine and clinopyroxene with the low CaO and FeO content are more conducive to the formation of magmatic Ni-Cu sulfide deposit.The findings lay a foundation for the direction and the prospecting potential of mafic-ultramafic magmatic mineralization in Northwest China.