The Stretch Tectonic Characteristics Research In Paleogene Of Heshan Sag In Pearl River Mouth Basin

Heshan sag is located in Pearl River Mouth basin with good exploration prospects.Based on the comprehensive analysis of regional angular unconformities,the stage evolution of tectonic subsidence,episodic activities of the fracture and the changes of ancient tectonic frameworks,There is a characteristic of incongruous multi-episodic rift in Heshan sag.Meanwhile,controlled by different intensity of fault activity,the spatial distribution and configuration of depositional system were distinctive in each episode:In early rifting episode,sedimentary process was entirely controlled by boundary fault and the fault activity was strong.The fan delta source controlled by the first scale tectonic transformation developed;In final rifting episode,the fault activity and the scale of tectonic transformation weakened,the shallow and braided delta developed;In the fault-depression stage,strata developed by layers.Strata were totally controlled by faults in initial episode,and there developed shallow-sea delta.In initial episode,the area accepted marine sedimentation and the sediment-gravity flows deep-water fan developed.