Abstract:
The periphery of Bogda Mountain in Xinjiang is an important oil and gas resource investigation area in China. The structural deformation and evolutionary history of this area are complex, and the tectonic reworking in late-stage was intense, making it difficult to restore early structural characteristics and constraining the progress of oil and gas exploration. Based on detailed structural analysis of 2D seismic data from the periphery of Bogda Mountain, the authors in this study focused on the newly identified Sangezhuang sub-convex and adopted a "buried mountain massif structural analysis" approach to systematically determine the structural deformation styles and evolutionary history of Bogda Mountain periphery. The theoretical contributions of this study are threefold. Firstly, it confirms that Sangezhuang sub-convex was the buried terminal of Bogda Mountain arcuate orogenic belt, and its Cenozoic tectonic modification was weak, leading to good preservation of early structures, which provided a critical "window" for restoring the tectonic evolution of Bogda Mountain. Secondly, it identifies the Carboniferous-Early Permian normal faults in the seismic data, providing key seismic evidence for a rift basin setting in Bogda region. Thirdly, it reveals that shallow structural deformation in the area is dominated by thrust nappe structures, with decollement structures being secondary, deepening the understanding of the deformation mechanisms of the "rift-inverted" orogenic belt. In terms of application, the results defined three tectonic evolution stages around Bogda Mountain, that is the Carboniferous-Early Permian rift basin extension, the Late Permian-Cretaceous multi-phase compressional orogeny, and the Paleogene-recent differential intracontinental orogeny. Among these, initial uplift occurred in the Late Permian, and large-scale uplift took place during the latest Jurassic-Cretaceous. This tectonic evolution sequence could provide crucial geological basis for predicting source rock distribution, reservoir evaluation, and oil and gas exploration deployment in this region.