Characteristics and evolution process of Cenozoic fault system in the western area of Wenchang A sag,Pearl River Mouth basin
Fault system development is an important manifestation of Cenozoic tectonic evolution in the western area of Wenchang A sag,the Pearl River Mouth basin.By using the latest 3D seismic data and finely characterizing the static characteristics of the fault system,combined with the calculation of fault activity rate to restore the dynamic evolution process of the fault system,the spatial and temporal differences in the development of the Cenozoic fault system in the western area of the Wenchang A sag are clarified.Based on the analysis of regional stress background,the genesis mechanism of fault system evolution is explored,and it is indicated that,the clockwise rotation of the regional extensional stress field at the northern margin of the South China Sea,caused by the subduction and collision between the three major plates,the subduction and disappearance of the ancient South China Sea,and the expansion of the new South China Sea since the Cenozoic era,controls the spatial and temporal differences in the evolution of the fault system.The results show that the development and evolution of the fault system in the western area of Wenchang A sag has undergone three stages of rifting,bending and tectonic activation,and three sets of predominantly NE(NEE),near-EW and NW(NWW)oriented faults have developed respectively,revealing the process of clockwise shift of the regional stress field extension from NW-SE to near-SN to NNE-SSW directions.Based on the combination and along-bearing relationship,it can be divided into two groups of overlapping fault zones:the early developed NE-oriented fault zone with strong activity intensity and extension property,and the later developed NW-oriented fault zone with low activity intensity and superimposed with certain slip nature,which is closely related to the pre-existing basement faults.The temporal and spatial differences in the evolution of the Cenozoic fault system in the western area of Wenchang A sag are a response to the clockwise rotation of the regional stress field at the northern margin of the South China Sea.
fault systemregional stress fieldpre-existing faultsthe western area of Wenchang A sagthe Pearl River Mouth basin
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NSTL
万方数据
