Syn-collisional extension and Ni-Cu sulfide-bearing mafic magma emplacement along the Irtysh Shear Zone in the Central Asian Orogenic Belt

The Central Asian Orogenic Belt was characterized by a long-lived accretionary history from Neoproterozoic to Paleozoic, followed collisional phase of orogeny in the latest Paleozoic with closure Paleo-Asian Ocean. However, Ni-Cu sulfide mineralization associated mantle-derived mafic magmas relatively short-lived. Thus, coherence between protracted and transient sulfide-bearing magmatism is difficult understand. We investigated both sulfide-barren intrusions along major suture zone Irtysh Shear Zone within understand origin short-lived context collision two arc systems Chinese Altai East Junggar regions. Zircon U-Pb dating results for show that they were only emplaced briefly 290 Ma 280 after subduction terminated (ca. 312 Ma), substantially earlier than 274−271 Ma). Zircons all sulfide-bearing/barren yield arithmetic mean δ18O values ranging 6.0 7.4‰, higher typical mantle value (∼5.3‰), which indicates their derivation metasomatized inherited signatures. δ11B rocks these range −17.2‰ −2.3‰, significantly lower those volcanic arcs (up +18‰), suggests metasomatic components source dominated sediment melts rather fluids. pressure calculated using amphibole thermobarometry shows parental shallower intrusions. This supported fact country are shallow crustal lithologies sedimentary rocks, whereas barren deeper high-grade metamorphic granites. Olivine has forsterite (Fo) contents 51.1 mol% 76.2 Ni 196 ppm 1312 ppm. These much (Fo = 72.6−79.4 mol%; 1022−1925 ppm), may have experienced extensive olivine crystallization. Notably, emplacement (290−280 Ma) coincidently overlapped period orogen-parallel extension 295−280 response Junggar. Syn-collisional lead rapid ascent at level, preventing significant loss crystallization depths, thus providing metal-rich potential mineralization. Our highlight syn-collisional an essential geodynamic mechanism controls orogenic belts.