Abstract: The Tarim Basin is a large craton basin developed in western China. The Bachu uplift is an important tectonic unit in western central uplift in the Tarim Basin. The boundary faults severely limit the range of the Bachu uplift. However, it is precisely the development of the boundary faults that makes the Bachu uplift formation a complex process. By exploring this formation process and its mechanism we can further study the characteristics and mechanism of deformation in the craton basin. In this work, we depicted the fault characteristics and geostructure of the Bachu uplift and built the tree-dimensional geological model based on drilling data and seismic interpretation. We further analyzed the formation mechanism of the Bachu uplift, taking into consideration of tectonic setting and evolutionary characteristics. The results show that seven major unconformities can be identified in the longitudinal direction, according to which, along with evolutionary characteristics, the Bachu uplift can be divided into seven tectonic layers. Based on the distribution characteristics of fault belt and stratigraphic tectonic configuration, the Bachu uplift is divided into four sub-tectonic units in the plane: western fault zone, Aqa-Tumuxiuke fault zone, Hemiros-Mazatag fault zone and eastern syncline zone. The Bachu uplift initially formed in the late Ordovician, was then strongly uplifted in the late Late Permian, and further uplifted in the early Neogene. During the Pliocene to Quaternary periods, the Bachu uplift was still subjected to extrusion transformation into the present form; its formation and evolution are mainly affected by the boundary faults.

Key words: Bachu uplift, tectonic-stratigraphic sequence, three-dimensional geological structure, genetic mechanism