The establishment of Ediacaran Dabure Formation in southern Qiangtang of northern Tibet and its significance

The Qiangtang terrane is situated in the hinterland of the Tibetan Plateau on the northern margin of Gondwana. Because of its particular tectonic location, the understanding of the origin and tectonic evolution of the Qiangtang terrane is important in examining the formation and evolution of the Tibetan Plateau, the breakup of the Gondwana supercontinent, and the evolution of the Tethys Ocean. The Dabure clastic rocks discovered recently are characterized by low compositional and textural maturity, and have been affected by lower greenschist facies metamorphism. The deposits exhibit the typical features of turbidites. Based on detrital zircons U-Pb dating, the authors obtained the most reliable youngest age of detrital zircons from the Dabure clastic rocks, which is ca. 550Ma. Combining the data obtained by the authors with previous work on the basalts in the Dabure area (the Dabure basalts), the authors tentatively suggest that the Dabure clastic rocks represent the late Ediacaran (ca. 550Ma) sedimentary record of the Qiangtang terrane. On the basis of section measurement and regional correlation, the Ediacaran Dabure Formation was established. The establishment of the Dabure Formation not only has important theoretical significance for revealing the evolutionary history of the Qiangtang terrane in late Neoproterozoic but also provides new clues for tectonic evolution of the northeastern margin of Gondwana.