关键词: 柴达木盆地, 新生代, 前陆盆地, 几何形态, 沉积速率

Abstract: The characteristics of different stages of petroliferous basins are of great significance for the restoration of basin evolution and the evaluation of hydrocarbon generation, storage and transportation conditions. In this study, we systematically reviewed previous studies on the nature and evolution of the Cenozoic western Qaidam basin. Based on the interpretation of seismic profiles combining with the basin tectonic geometry, sedimentation rate, sedimentation phase, sedimentation cycle, sedimentation center migration and unconformity contact relationship within the basin, we concluded that the Cenozoic western Qaidam basin, as a large intracontinental depression in a compressional environment, has an asymmetric geometric configuration in the seismic section, high deposition rate but slightly lower than the western typical foreland basin, and migration of sediment centers due to strong shortening under overcompensation, with obvious reverse cycling sedimentary-tectonic development. Importantly, the deposition of Shizigou Formation is considered as the sedimentary boundary of the Cenozoic western Qaidam basin, showing that in the early stage, fine-grained far-source sediments were developed, belonging to a depression basin; While, in the later period, the sedimentation rate increased significantly, and the coarse-grained deposition developed, which had the characteristics of atypical foreland basin. The fact significantly suggests that it’s controlled by the combination of tectonic activity of the surrounding mountains and overcompensation state of the basin.

Key words: Qaidam basin, Cenozoic, foreland basin, geometric pattern, sedimentary rate