The Yarlung Zangbo suture zone records the opening and closing history of the Neo-Tethys Ocean. In this paper, we presented new radiolarian chronology, sandstone petrology and detrital zircon U-Pb data from the Najiu mélange within the Yarlung-Zangbo suture zone in the south of the Zhongba area. Our data indicated that the chert matrix in the Najiu melange contain well preserved Early Barremian radiolarian fossils, including Pseudodictyomitra carpatica with typical molecules. The sandstone blocks in the mélange are mainly lithic sandstones, and the maximum deposition age obtained from detrital zircon lie in the range of 95～73 Ma. Provenance analysis of the detrital zircon age showed that the sediments was derived from the Gangdese arc. The coherent quartz sandstone on the south side of the Najiu melange is Early Cretaceous in age, and the detrital zircon U-Pb provenance is typical of Tethys Himalayan affinity. Our data show that the Early Cretaceous chert matrix and late Cretaceous sandstone block constitutes the Cretaceous accretionary wedge and was obducted over the Tethyan Himalaya during India-Asia collision.
Guo Xudong Ding Lin Cai Fulong Wang Houqi Yue Yahui. Subduction and accretion process of the western segment of the Yarlung Zangbo suture zone in Zhongba area, Tibet[J]. Chinese Journal of Geology, 2019, 54(4): 1031-1047.