Permian mafic-ultramafic magmatism and sulfide mineralization in the Central Asian Orogenic Belt: A review

Abstract

World-class magmatic Ni-Cu-(PGE) deposits have been extensively studied and are thought to occur in extensional intraplate settings. Recent reports indicate significant magmatic sulfide mineralization within mafic–ultramafic intrusions in convergent margin setting, including the Central Asian Orogenic Belt, Kunlun Orogenic Belt, Appalachian Orogen, and Variscan Orogenic Belt, highlighting notable Ni-Cu resources. Understanding the petrogenesis and metallogeny of these sulfide-bearing intrusions is thus critical for comprehending the magmatic Ni-Cu-(PGE) sulfide mineralization of basaltic magmas. Preliminary studies suggest that magmatic sulfide deposits in convergent margin setting show characteristics distinct from those in intraplate settings. These deposits formed from siliceous high-magnesium basaltic (SHMB) magma, contrasting with high-magnesium basalt in intraplate settings. SHMB-like magmas result from hydrous melting of the metasomatized mantle sources at relatively lower temperature compared to those in intraplate settings. Intrusions in convergent margin settings generally arise from multiple magma injections of varying compositions, a feature of the unique magma emplacement process in compressional settings. SHMB-like magmas, rich in Cu and Ni, can achieve sulfide saturation through selective crustal contamination during emplacement. Comparing deposits in convergent margin and intraplate settings reveals that the difference of magmatic sulfide deposits stem from different mantle sources and evolution histories of magma conduit systems.