The Late Silurian Langmuri Cu-Ni Deposit in East Kunlun Orogenic Belt: An Example of Magmatic Sulfide Deposit in a Post-Collisional Extensional Setting

The East Kunlun orogenic belt (EKOB), located in the northeastern part of the Qinghai-Tibet Plateau, is a significant Cu-Ni mineralization region associated with the geological evolution of the Paleo-Tethys and Proto-Tethys stages. Orogenic environments in this region exhibit considerable metallogenic potential, with two distinct metallogenic models: the subduction-related island arc model and the post-collisional extensional model. This study investigates the petrology, zircon U-Pb chronology, and geochemistry of ore-bearing intrusions in the Langmuri Cu-Ni deposit. The results reveal that the wehrlite yields a zircon U-Pb age of 420.0 +/- 1.4 Ma, with an average epsilon Hf(t) value of -5.5 and significant Nb-Ta negative anomalies. These features suggest that the parental magma was likely derived from the partial melting of a metasomatized continental lithospheric mantle. Additionally, crustal contamination during magma ascent triggered significant crustal sulfur assimilation. The Langmuri deposit represents a mineralization event formed during the final tectonic stage of the Proto-Tethys Ocean in a post-collisional extensional setting. Slab breakoff released hydrous fluids and melts that metasomatically enriched the lithospheric mantle, thereby providing the material basis for magmatic sulfide segregation.