Metallogenic process of magmatic Cu-Ni (PGE) sulfide system: Insights from Sr-Nd-Hf-S isotopes

Magmatic Cu–Ni (PGE) sulfide deposits constitute one of the important archives of critical metals and have important significance in the current global focus on new energy technologies. The Jinchuan deposit in China is a world-class magmatic copper-nickel sulfide deposit, with the largest nickel reserves and the second-largest copper and cobalt reserves in China. The genesis of this deposit remains debated. Here we apply multiproxy Sr–Nd–Hf–S isotopes and whole-rock geochemistry of mineralized and barren lherzolites in this deposit to understand the metallogenic system. The mineralized lherzolites Jinchuan are enriched in Fe, S, Cu, and Ni compared to barren lherzolites, reflecting sulfide accumulation, whereas the amphibole-rich samples suggest interaction with hydrous melts. The barren lherzolite has more concentrated Sr isotopes (∼ 0.711) than the mineralized samples (0.7093 to 0.7205). The Nd isotope ratios ( 143 Nd/ 144 Nd) for mineralized lherzolites range from 0.511801 to 0.512107, and those of the barren lherzolites range from 0.511936 to 0.511862. The Hf isotope values for mineralized lherzolites range from 0.282239 to 0.282560, and the barren lherzolites show a range of 0.282444 to 0.282347. The Nd and Hf isotopes indicate an enriched mantle source with deep crustal contamination, whereas Sr isotopes were strongly modified by alteration. The sulfur isotope values (δ 34 S = –3.74‰ to 2.81‰; anomalous Δ 33 S) reveal contributions from both mantle sulfur and Archean sedimentary sources. These results demonstrate that the Jinchuan deposit formed through mantle-derived magmatism, sulfide saturation and segregation, carbonatite–sulfide interaction. The study highlights the combined role of enriched mantle, deep crustal assimilation, and recycled sulfur in controlling ore genesis, providing new isotopic constraints on the formation of world-class magmatic Ni–Cu (PGE) sulfide deposits.