Sources and Evolution of Sulfur Isotopic Composition of Sulfides of the Kharaelakh and Pyasino–Vologochan Intrusions, Norilsk Ore Region

Abstract—: The paper discusses a problem of the source of sulfide sulfur in economic ore-bearing intrusions of the Norilsk type and less ore-bearing (subeconomic resources) intrusions of the Zub type of the Norilsk Complex. The data of previous studies indicate the relatively homogenous S isotopic composition of ore-bearing intrusions with a general enrichment in heavy (34S) isotope, which was considered one of favorable searching criteria for rich mineralization. The representative volume of new data on S isotopic composition of sulfides of the Kharaelakh intrusion showed that the sulfide liquid of disseminated and massive ores underwent progressive enrichment in 34S isotope from root–rear parts to the intrusion front. This trend contradicts models that suggest a primary heavy S isotopic composition of a deep source. Our genetic model envisages the decomposition of sulfates in an intrusion aureole, reduction of sulfate sulfur by hydrocarbons, and further assimilation of hydrogen sulfide by magma. This model serves for identifying the patterns of the distribution of orebodies within the deposits and directions of further exploration in the region.