Deep segregation-injection ore-forming process and metallogenetic model for magmatic Cu-Ni (PGE) sulfide deposits—Geological comparative study on two deposits exemplified by Voisey`s Bay (Canada) and Jinchuan (China)

In this paper, geological and mineralization characteristics and metallogenetic model of Jinchuan Cu-Ni (PGE) magmatic sulfide deposit are systematically analysed and compared with Voisey`s Bay Cu-Ni (PGE) deposit (Canada), and the results show that the two world-class Cu-Ni (PGE) deposits have some common geological characteristics, and so, there are similarity and comparability on ore-forming and evaluation of the deposit. That means ore bearing magma at depth pulsating invasion along the magma flow conduit results in a large deposit in upper magmatic room which appears it was generated from a small rock mass. Several key aspects of the characteristics on ore-forming process and metallogenetic model emerged as follows: i) ore-bearing magma pulsating invasion in sequence reveals that segregation and differentiation has occurred during primitive magma staying at a lower magmatic room and resulted in layering structure of magma , ore-bearing magma, sulfide-enriched magma and sulfide mass ; ii)ore forming process occurs in a dynamic magma flow during pulsating invasion, melted magma mass contains volatile composition, acutely invasion results in brecciated wall rocks; iii) ore bearing magma invades along the same conduit or overpass to access to the bottom or upper part of the previous invasions to form ore body; ⅳ) magma interacts with wall rocks , exchanges some components and enrich metallogenetic materials during transportation .It is clarified that ore-bearing magma pulsating invasion and subsequent magma re-supply to be a very important ore-forming mechanism through which sulfide-bearing mafic-ultramafic magma assembles along the magma flowing conduit at depth to form super-larger Cu-Ni (PGE) magmatic sulfide deposits during the process of Magmatic Ni-Cu sulfide deposits forming by “injecting of sulfide-bearing magma segregated at depth”.