The Tectonic Deformation Characteristics of the Pearl River Mouth Basin and Tectonic-sedimentary Forward Modeling of the Baiyun Sag

The relationship between the tectonic evolution of the Pearl River Mouth Basin and the spreading movement of the South China Sea has always been an hot issue, the deformation information of the basin is very important for understanding the multiple spreading movements of the South China Sea. In order to study the overall structural deformation characteristics of the Pearl River Mouth Basin and the tectonic evolution of the Baiyun Sag, we reinterpret three regional seismic profiles across the Pearl River Mouth Basin and one across the center of the Baiyun Sag. We also carry out forward modeling on the main normal fault system of the Baiyun Sag. The three seismic sections all reflect the structural characteristics of ‘three uplifts and two depressions’. It is also found that the cumulative amount of tectonic deformation is the largest in the central part of the basin, of which the Baiyun Sag is the most prominent. Based on the tectonic-sedimentary deformation characteristics reflected by the seismic section across the Baiyun Sag, we use a 2-D Move forward modeling to study the depression-controlled normal fault system based on fault geometry. The results reveal that the Baiyun Sag is controlled by three main faults, and the active time of the main faults is between the T80 and T70 reflector interfaces (ca. 38–32 Ma). The intense activity time and the sedimentary distribution characteristics in the Baiyun Sag indicate that its formation may be related to the initial rifting of the northern South China Sea and superimposed by the spreading of the northwest sub-basin. After the spreading of the northwest sub-basin, the whole Pearl River Mouth Basin was mainly affected by the spreading of the eastern sub-basin. © 2022 Science Press. All rights reserved.