Abstract：Based on the interpretation results of the structural characteristics of 22 seismic profiles of Huanghua Depression in Bohai Bay Basin，the amount of extension，the extensional coefficient and the extensional ratio have been calculated by technique of balanced geological cross-sections, moreover， the spatial and temporal distribution of the extension amounts has been analyzed in this paper.The results show that Huanghua Depression was characterized by episodic evolution in the Cenozoic，and also the temporal and spatial distribution of extension amount of this depression was very uneven.On one side，the extension amount in space was mainly caused by the stretching displacement of the main basin boundary faults.The extension amount was correspondingly larger where the stretching displacement of the main basin boundary faults was bigger.On the other side，the main extensional period can be divided into three periods which are the Eocene，the Oligocene and the Neogene.Among them，the extension in Eocene occurred mainly in the southern part of the basin while the one in the Oligocene occurred in the north-central part.And also，the extension amount in the Neogene was smaller and mainly occurred in the central.The temporal and spatial distribution of extension amount was controlled by basin tectonic deformation and tectonic evolution.In the Eocene，the stretching displacement of NNE trending Cangdong fault was the main factor that controlled the basin extensional deformation and the amount of the stretching displacement was larger in the southern area of the basin.In the Oligocene，the amount of the stretching displacement was relatively large in the north-central part.At the same time the NE trending basement normal fault which was induced by dextral strike-slip of the NNE trending basement fault in inner basin contributed a lot to the basin extension.In the Neogene，the NNE trending basement fault still had dextral strike-slip displacement when the basin was in the thermal subsidence process after the basin rift.It was the reason which caused the NE trending normal fault in the cover rock in the central part of the basin.
Dong Min,Qi Jiafu,Yang Qiao et al. Characteristics of extension amounts and their temporal and spatial distribution of the Cenozoic of Huanghua Depression in Bohai Bay Basin[J]. JOPC, 2013, 15(3): 327-338.
