CHARACTERISTICS AND FORMATION MECHANISM OF FAULTS IN QIONGDONGNAN BASIN

In Qiongdongnan basin,have developed three sets of faults,trending in NE, roughly EW and NW respectively. Of which, the NE-and EW-trending faults are major controlling faults. The early rifting stage of the Qiongdongnan basin was controlled by pre-existing basal faults and there developed many rifting structures. The late stage of the basin was mainly controlled by thermal subsidence and short of fault activity. The sedimentation of the basin shows a typical double-layer structure. Controlled by the retreating Pacific subduction zone, India-Tibet collision and South China Sea opening, the rifting of the Qiongdongnan basin could be divided into two main stages, that is strong extension from Eocene to early Oligocene and weak extension from late Oligocene to early Miocene.