The entire faulting system developed during the synrift stage is dominatedby continuous NE-NNE trending fault sets and continual EW trending fault sets. During the syn-rift stage a series of grabens and half grabens developed along the major northeast and north-northeast trending fault sets. Tectonic evolution of the postrift stage can be sub-divided into substages I (36.0–25.2 Ma) and II (25.2–5.2 Ma), underwent the Huagang Movement (25.2 Ma) and the Longjing Movement (5.2 Ma) (Fig. 2a).