珠江口盆地西江主洼主干断层活动强度及构造演化特征分析

摘要

在文昌组和恩平组层序细分的基础上,对西江主洼主干断层的古近纪活动强度进行了分析;并且在此基础上利用平衡剖面技术对洼陷的主干剖面进行了构造演化恢复.认为:①NE向的F1号断层是区域性的控洼断层,对沉积充填及构造演化有重要作用;②多数主干断层在文昌期活动性较强,在恩平期活动较弱;③西江主洼构造演化阶段可分为初始断陷期、强烈断陷期、断拗过渡期和热沉降期,其中初始断陷期和强烈断陷期对于洼陷的形成、扩张以及沉积充填有十分重要的意义.%Based on the sequence classification of Wenchang and Enping formation,the activity intensity of main fault in Xijiang main sag was analyzed.And the tectonic evolution of main sections was also studied according to the balanced section technique.It's believed that,firstly,the fault number F1 in NE direction was a regional sag-controlling fault,and it had very important influence on the sedimentary filling and tectonic evolution;secondly,most of the main faults had a strong activity intensity in Wenchang stage while weak in Enping stage;thirdly,the tectonic evolution of Xijiang main sag could be divided into four stages,which begun with starting fault-depression stage,and followed strong fault-depression stage,fault-sag transition stage,thermal subsidence stage.Among the four stages,the stage of starting fault-depression and strong fault-depression were significant for the formation,enlargement and sedimentary filling of the Xijiang main sag.