Tectonic and metallogenic processes along the east Tethyan metallogenic domain (Lhasa-southern Tibet, Kohistan island arc and Chagai magmatic belt): a perspective review

The eastern Tethyan metallogenic domain (ETMD), which resulted from the collisions between the Indo-Eurasian and Arabian-Eurasian plates, hosts several world-class porphyry copper (Cu) systems. This review evaluates the geological and geochemical characteristics of three key arc segments within the eastern Tethyan metallogenic domain (ETMD): the collision-related Lhasa terrane and the subduction-related Chagai and Kohistan arcs in order to assess the influence of tectono-magmatic processes on porphyry Cu-Au fertility. In the Lhasa terrane, fertile Miocene adakite-like intrusions originated from partial melting of thickened mafic lower crust, while ore-barren adakite characterized by relatively lower εNd(t), higher ⁸⁷Sr/⁸⁶Sr(i), and decreased fluid-sensitive element ratios (Ba/La, Pb/Ce, Sr/Nd), indicating reduced slab-derived fluid input and increased contributions from ancient basement crust. The Kohistan arc presents evidence of early island arc porphyry mineralization within Cretaceous Mirkhani granodiorite-diorite intrusions; however, high-pressure differentiation under garnet stability accompanied by metamorphic dehydration caused sulphide and volatile loss, limiting ore fertility than fertile Gangdese arc. The Chagai arc evolved from a juvenile island arc to a mature, mineralized continental arc with at least five mineralization phases from the Eocene to Pliocene. Fertile and barren porphyries here share similar trace element, rare earth element (REE), and Sr isotope patterns, reflecting a commonly enriched mantle source with variable crustal contamination. Fertile porphyries display large-ion lithophile element (LILE) enrichment, high-field-strength element (HFSE) depletion, and negative Ti-Nb-Ta anomalies, consistent with oxidized magmas formed in active subduction zones with significant crustal input. Comparative analysis highlights the crucial roles of crustal thickness, subduction-derived fluids, and tectonic settings in controlling porphyry fertility. This synthesis advances understanding of metallogenic processes and informs exploration strategies in convergent margin environments.