Outcrop Sequence Stratigraphy of the Paleogene Strata of Dahonggou Region in the Northeast Margin of Qaidam Basin

This paper studies in detail the sedimentary characters of the Paleogene-Neogene clastic succession exposed in the Dahonggou section in the northeast margin of Qaidam Basin.The results indicate that the depositional systems of Paleogene strata in Dahonggou section consist of alluvial fan,braided river delta littoral,and shallow lake from bottom to top,representing a fining-upward and regradational sequence.According to the sedimentary facies,stacking patterns of parasequences and relative lake level fluctuation,sequences of Paleogene strata in the Dahonggou section are divided into six 3th sedimentary sequences and twenty-seven 4th order sequences.It also has reconstructed the course of relative lake level fluctuation and sedimentary evolution of the Paleogene in Dahonggou region in the northeast margin of Qaidam Basin.