Role of volatiles in intrusion emplacement and sulfide deposition in the supergiant Norilsk-Talnakh Ni-Cu-PGE ore deposits

The Norilsk-Talnakh orebodies in Siberia are some of the largest examples on Earth magmatic Ni−Cu−platinum group element (PGE) deposits, formed by segregation immiscible sulfide melts from silicate magmas. They show distinctive features attributable to degassing a vapor phase during ore formation, including: vesiculation host intrusions, widespread intrusion breccias, and extensive hydrofracturing, skarns, metasomatic replacement country rocks. Much was generated assimilation anhydrite carbonaceous material, leading injection suspension fine droplets attached gas bubbles into propagating tube-like sills ("chonoliths"). Catastrophic exsolution associated with drop magma overpressure at transition vertical horizontal flow enabled explosive propagation chonoliths, rapid "harvesting" gravity deposition characteristic coarse globules that form much ore, fluid interaction