Establishment of Upper Jurassic Duiwangshan Formation in Duobuza area, Gerze County, Tibet, and its significance

The Duiwangshan Formation is a rock assemblage developed in the south of Qiangtang plate and consists of andesite, liparite, basaltic tuff and minor basaltic andesite interlayer. It has obvious rhythm distribution characteristics between extrusive facies and sedimentary facies of magma. Conducting LA-ICP-MS U-Pb dating, the authors obtained andesite average ²⁰⁶Pb/²³⁸U age of 150.5±0.6Ma, which indicates Duiwangshan Formation should have been formed in middle-late period of Late Jurassic. The Late Jurassic Duiwangshan Formation was established based on the detailed section measurement and regional correlation, which has important geological significance for the completion of the stratigraphic system in Bangong Co-Nujiang Suture Zone (BANSZ) and the study of tectonic evolution of Bangong Co-Nujiang Ocean in Late Jurassic.