Linking mantle plume contributions to magmatic Ni-Cu-(PGE) sulfide deposit formation

The contributions of mantle plumes to the formation of magmatic nickel–copper–platinum-group element sulfide deposits remain poorly characterized. Here, we assess this ambiguity by utilizing the Hg isotope composition of sulfide ores from the giant Jinchuan deposit and those within the Central Asian Orogenic Belt, which represent magmatic sulfide deposits that formed within intracratonic and orogenic settings, respectively. The Δ199Hg values of the sulfide ores within the Central Asian Orogenic Belt (0.01 ± 0.16‰, 2 SD) and Jinchuan (−0.03 ± 0.11‰, 2 SD) are similar to those of mantle plumes (0.0 ± 0.1‰, 2 SD), but distinctly different from those of metasomatized lithospheric mantle (non-zero). This supports a plume origin for magmatic sulfide deposit formation, regardless of their formation in intracratonic or orogenic settings. These findings help to better understand the genesis of magmatic sulfide deposits in a diversity of tectonic settings and provide new insights into Hg isotope behavior during magmatic sulfide mineralization. Δ199Hg values in Central Asian Orogenic Belt and Jinchuan sulfide ores match mantle plume signatures and differ from metasomatized lithospheric mantle, indicating a mantle plume origin for these deposits, according to Hg isotope analysis of the Ni–Cu PGE ore samples.