Volatile evolution of magmas associated with the Bairong deposit, Tibet, and implications for porphyry Cu-Mo mineralization

•Multi-stage intrusions from pre- to post-mineralization at Bairong are studied.•They formed at 14.1 to 11.6 Ma and derived from a cogenetic magma chamber in a post-collisional setting.•They are all oxidized and hydrous with comparable magmatic S contents, but have different Cl contents.•Fluid exsolution and buffering effect of magmatic anhydrite possibly result in S-Cl decoupling.•Oxidized and hydrous magma with effective fluid exsolution is the key factor for Bairong Cu-Mo mineralization.