Mesozoic-Cenozoic exhumation of the giant Jinchuan Ni-Cu sulfide deposit, China: Evidence from single-grain apatite (U-Th)/He ages

The Jinchuan Ni-Cu sulfide deposit in the northeastern margin of the Tibetan Plateau is one of the largest magmatic sulfide deposits on the earth. However, the post-mineralization exhumation history of this deposit is poorly understood. We report new apatite (U-Th)/He data for bedrocks from the Jinchuan deposit and this new dataset reveals two periods of rapid exhumation at intervals of - 115-95 and - 65-55 Ma. Considering the tecton-thermal events in the adjacent terranes, the earlier stage of rapid exhumation during - 115-95 Ma likely resulted from the Lhasa-Qiangtang collision, whereas the late stage of rapid exhumation during - 65-55 Ma should be a geomorphological response to the initial collision of the Indian and Eurasian plates during the Cenozoic. The rapid exhumation during - 65-55 Ma raises the idea that the northeastern Tibetan Plateau uplifted to a certain extent at the early stage of the India-Asia collision during the early Cenozoic.