Acta Petrologica et Mineralogica

As a type of magmatic-hydrothermal deposit, porphyry copper deposits are closely related to the migration of Cu from melts to fluids. Many pieces of research have shown that chlorine plays a crucial role in this process, thereby the chlorine content directly determines the fertility of magma. The chlorine required for the mineralization of porphyry copper deposits in arc settings mainly comes from the subducting oceanic crust. But such an end-member is absent during the formation of a collisional porphyry copper deposit, the origin of chlorine in collisional settings is still uncertain. To further advance the research on the above scientific issues, this review summarizes the mineral characteristics of chlorine-containing magmatic minerals;estimates the chlorine content of fertile magma in collisional settings via apatite;calculates the exchange coefficient of amphibole in juvenile lower crust;discusses the chlorine source for porphyry copper deposit in collisional settings. The results show that: ① the Cl content in apatite, amphibole and biotite can be used to indicate the Cl content in melt or fluid;② Fertile magma from collisional settings have lower Cl content than its counterpart from arc settings, but the barren magma from arc environment have higher Cl content than its counterpart from collisional settings;③ The juvenile lower crust in Gangdese belt are the products of arc magma, and the consequent high Cl content can be inherited by the amphibole;④ The ultrapotassic magma formed by partial melting of mantle wedge during subduction of Indian continental crust may have high Cl content. And the Cl content of the residual melt will be further increased by the crystallization of amphibole, which is promoted by the addition of water-riched ultrapotassic magma.

collisional settings; chlorine; porphyry copper deposits; Tibet