Quantitative Analysis of Faults in Huizhou Sub-basin, Pearl River Mouth Basin

This study used 2D seismic profiles to investigate the Cenozoic evolution of faults in the Huizhou Sub-basin. It aims to define the basin structure style through describing the geometric features of the faults and quantitatively analyzing their activities. The results indicate that the boundary faults in the Huizhou Sub-basin display en echelon arrangement in plan view, which indicates that, it was caused by a kind of oblique extension. Calculating the fault slips shows long-term activities of faults occurred in the basin, and some boundary faults kept active after 5.5 Ma. The evolution history of the fault system is reconstructed. Initially, during the Eocene–Early Oligocene, mainly NNE-NE and NW trending faults and NE striking grabens and half-grabens formed in the basin and a series of faults system controlled the deposition. During the Late Oligocene–Early Miocene, the structural activities were relatively weak, the fault activity and the fault growth rate decreased sharply. Finally, in the late stage from Late Miocene to the present, the structure movement was re-activated, and some faults were also reactivated. Our study will help better understand the structural features and evolution of the petroleum-bearing basins in the northern margin of the South China Sea.