Detailed Sequence Stratigraphy Study Of Upper Permian At Southern Bogda Mountains In Xinjiang

It is a long-range study program to make sedimentary, sequence stratigraphy , paleoecology, 'paleoclimate analysis of the intact and well development Mid-Permian — Lower-Triassic nomarine strata in Xinjiang Uygur Autonomous Region of northwest China. This dissertation take the super representative Mid-Permian— Lower-Triassic sections located in Tarlonggou and Taodonggou, southern Bogda Mountains as study elements and start point, measured the Upper Permian (Quanzijie Formation, Wutonggou Formation, Guodikeng Formation) of the two sections at a cm-scale and a 50-km~2 (1: 50000) area between Tarlonggou and Taodonggou was mapped, base on all the work that have been done, detailed sedimentary facies, sedimentary environment and sequence stratigraphy study have been completed.A great deal of paleosol was found in Tarlonggou and Taodonggou sections, especially the super thick stacking paleosol, indicates that the climate at that time was from semi-arid to sub-humid, which was suitable for soil-forming process. Base on integrated study of sections, well log, bore log and interior compilation, colligate geological background information, lithologic association, sedimentary structure, geochemistry and paleontology characters, draw a conclusion that sedimentary facies of Tarlonggou and Taodonggou in Late-Permian composes of shallow littoral facies, delta facies, lake plain facies and fluvial faciesBecause of the feature of complexity, rapid facise changes, lack of uniform unconformity and multifactor controling of nonmarine sedmentary, apply the thought of high-resolution sequence stratigraphy that is more suited to nomarine strata, in base of high resolution measured sections, set up the bottommost and the smallest high resolution sedmentary cycles that can reflect single sedmentary event to identify the direction of short baselevel cycles, by summing up the characters and trends of the change in basic-cycles, confirm direction of the change in higher baselevel cycles. In this way, finally, identify five mid-baselevel cycles in Upper Permian. By comparing the two sections establish a landscape orientation isochronous strata framework and a...