Abstract:

The Changfanggou Group(P₂-T₁),developed at the east part of Junggar is represented by some 1000m of elastic sediments which comprises fluvial-fan factes,meandering stream factes and low-sinuosity stream facies,braided stream factes and lacustrine fade.Sedimentary properties and the changes in fluvial styles reflect an increasing aridity and decreasing flora population under cyclic tectonic active condition during P₂-T₁ period.The changes in paleoclimate and paleotectonics resulted in the variation of sedimentary environment.The variation from meandering stream to low-sinuosity stream was a process from warm and humid climate,luxuriant plants to hot and semiarid climate, nonvegetation enveronment.The low sinuosity streams become braid streams and wedge-shaped braid factes developed in the study area with the uplift of provenance.