Reconstruction Of Permian And Triassic Prototype Basin And Analysis Of Lithofacies Paleogeographic Characteristics In Western Turpan-Hami Basin-Eastern Junggar Basin

The western-eastern Turpan-Hami Basin is located in a typical superimposed basin with abundant oil and gas resources in China.The study area has experienced multi-stage tectonic movement superposition and transformation.The structure and stratigraphic distribution of deep strata,especially the characteristics of deep prototype basin,are the main problems restricting oil and gas exploration.Therefore,the restoration of prototype basin and the analysis of lithofacies paleogeographic characteristics are the necessary means to find favorable source rock development areas and guide the breakthrough of oil and gas exploration in Upper Paleozoic-Lower Mesozoic.In this paper,the Permian and Triassic in the western-Jundong area of the Turpan-Hami Basin are taken as the research object.Using previous research,logging data and seismic data,the tectonic evolution law of the western-Jundong area of the Turpan-Hami Basin is summarized.Combined with the prototype basin pattern and thickness distribution characteristics obtained by erosion recovery,the lithofacies paleogeographic characteristics of the study area are analyzed.The results show that during the sedimentary period of the Middle Permian,the rifting entered its heyday,and the rift trough was developed centered on the Bogda area.The Bogda rift trough was connected with the Taibei depression and the Tainan rift trough to form a unified deep lake and semi-deep lake deposit.Luxi uplift and Takequan uplift in the west of Tuha basin are developed and become the source area.The shore-shallow lake deposits are developed in the central and eastern parts of the Zhundong Depression,and the Shaqi Uplift provides provenance for the peripheral braided river delta.During the sedimentary period of the Upper Permian,the Bogda area experienced low-amplitude uplift,which divided the eastern Junggar Basin and the western Turpan-Hami Basin into two regions: north and south.Taibei Depression and Tainan Depression in the west of Turpan-Hami Basin are mainly fan delta-lacustrine sedimentary systems,and the range of Luxi Uplift and Takequan Uplift is expanded to provide provenance for its periphery.The Zhundong depression is dominated by shore-shallow lake deposits,the Beisantai uplift is formed,the Shaqi uplift is expanded,and the two uplifts provide provenance for the peripheral fan delta.During the middle and upper Triassic sedimentary period,the Bogda low uplift continued to uplift and develop into the Bogda Mountain;keyayi depression and Tuokexun depression are developed in the west of Tuha basin,Taibei depression and Tainan depression are further expanded,the sedimentary center moves southward,braided river delta deposits are developed in the southern margin of lacustrine deposits,and fan delta deposits are developed in the piedmont area of Bogda mountain.The range of Beisantai uplift and Shaqi uplift in the eastern Junggar Basin continues to expand.The Zhundong depression area on the south side of the uplift develops shore-shallow lake deposits,and braided river delta deposits are developed around the uplift.