Abstract: The analysis of tectonic evolutionary stages serves as the basis for addressing the basin formation and evolution,also as the important foundation for delineation of the spatial-temporal framework for oil and gas accumulation,and as a key reference for establishing the tectonic movement chronology for continents.Based on the information from deep boreholes and the high resolution reflection seismic data within the Junggar Basin,we delineated the tectonic evolution stages of the basin and explored the characteristics of every stage,through analyzing the tectonic subsidence and the tectono-stratigraphic sequence,and the tectonic events in the periphery of the basin.The results show that the basin has undergone six evolutionary stages,including the Carboniferous fault depression-depression,the Permian fault depression,the Middle Permian and Triassic foreland basin,the Jurassic extensional fault depression-compresso-shear basin,the Cretaceous-Paleogene intra-continental depression,and the Neogene-Quaternary intra-continental foreland basin,which can be grouped into four non-isochronous extension-compression cycles,namely the Carboniferous,Early Permian-Triassic,Jurassic,and Cretaceous-Quaternary cycles.The extension tends to be weaker,but the compression gets stronger north-southwardly,with time passing by.On the whole,the basin exhibits the character of "thrusting on its periphery and shrinking in scope",with the west-eastward shortening rate being 35.8%,almost three times of the 12.2% on the north-south direction.The compression from the west took place mainly during the Middle Permian-Early Triassic,while besides that,the compression from the east was still strong in the Late Triassic,early Middle Jurassic,and Late Jurassic-Early Cretaceous.The compression from the south took place strongly in the Middle and Late Permian,the Middle and Late Jurassic,and the Pliocene-Quaternary; while the extensive thrusting on the northern margin occurred in the Late Cretaceous.The pronounced spatial-temporal differences of the above extension and compression have given rise to the complex superimposed composite basin architecture,thus different tectonic units show strong differential evolution and unique features of oil and gas accumulation.

Key words: geological structure, tectonic subsidence, tectono-stratigraphic sequence, tectonic evolution, superimposed basin, Junggar Basin