Sedimentary Characteristics And Structure Significance Of The Upper Triassic Songre Formation At Dengmu Area, Jiacha, Tibet

The yarlung zangbo river is the combining site of Gangdese block and Himalaya block. Along the Yarlung Zangbo River south of a large area of exposed a deep half deep-sea sedimentary strata. Among them, in the north and the south in the Yangbajing –Qiongdui(or Jianzi-Langkazi) fracture to the East is a largely Late Triassic world of green schist facies and shallow metamorphic rock series, called "Langjiexue group". In this paper, we selected the songre formation of the study group as the research object, and analyzed the characteristics of the songre group. Through the analysis of the sedimentary composition of the Song Dynasty, it is considered that the formation of sandstone and mudstone is mainly composed of sandstone and mudstone. In the study of sedimentary facies, it is considered that the thermal formation of the Song Dynasty is a type of slope fan, which is further divided into 5inner fans, 13 Chinese fans and 9 outer fans. Through the study of paleocurrent direction, songre formation of paleocurrent direction of flow for the main single,Southeast 170 degrees 190 degrees ~ nanxi. And think that the sediments come from the north. Through the analysis of heavy minerals can be seen, songre formation is zircon + rutile + leucoxene combined with high content of characteristics. The content of rutile in the song is higher, and the reaction is influenced by the hydrothermal solution after the medium and high temperature magmatic period. The content of pyrite in the song group is higher, which indicates that there is a small amount of magnetite in volcanic hydrothermal activity. Through the sandstone rock geochemical data analysis, and tectonic setting of investment analysis, provenance investment map analysis can be found songre formation sandstone maturity are relatively high, songre formation of tectonic setting is active continental margin.