Geological comparative study of two Ni-Cu sulfide deposits of Maniitsoq and Jinchuan

The Maniitsoq nickel-copper deposit is located about 160 km north of Nuuk, Greenland. The deposit is a very large high-grade deposit with 19.5 million tons nickel @1.08%, and copper @ 0.54%, reached the world class scale. The authors comprehensively collected and analyzed the relevant data of the deposit, and compared it with China's Jinchuan nickel ore deposit. They occurred in same tectonic environment, with same rock characteristics, and mineralization features between the Maniitsoq nickel copper deposit in Greenland and the Jinchuan nickel copper deposit in China. Although the Maniitsoq and Jinchuan intrusive bodies are not large in scale, but the Jinchuan nickel copper deposit produces world-class ultra large copper nickel platinum group metal deposits, which is in line with the theory of "small rock mass forming large ore". Maniitsoq is likely to be the next world-class nickel copper sulfide deposit. By comparison, the Maniitsoq nickel copper deposit and the Jinchuan copper nickel deposit have similarities in diagenetic and deposit characteristics, and both belong to fissure penetrating magmatic deposits, i.e. "deep liquation-injection mineralization" ore-forming mechanism.

Mineralization occurs during the upwelling process in a dynamic magmatic environment, where magma melts are rich in volatile components and the upwelling activity is intense. During the migration process, magma interacts with surrounding rocks, undergoes component exchange, and accumulates ore-forming materials. Early sulfur saturation mechanisms such as crustal contamination or magma temperature reduction are necessary conditions for magma mineralization during channel migration or intrusion. In the process of deep melting penetration mineralization, the upwelling of ore bearing magma and subsequent magma recharge and mixing are important mechanisms for the accumulation of sulfides in the channels of Mg-Fe ultramafic rocks to form super large copper nickel platinum group metal deposits. We suggest that the exposed Maniitsoq intrusions represent the Ni-rich upper portions of magma conduits implying that there is potential for Cu-rich sulfides in unexposed deeper portions of the belt.