The east tectonic belt of Huanghua Depression includes Qidong

Baidong and Xingang tectonic belts.The reconstruction of the Cenozoic subsidence history of the east Huanghua tectonic belt was made by denuded amount analysis of three boreholes in the basin. The tectonic subsidence curves of the wells show that a rapid tectonic subsidence happened in the study area during Shahejie period

suggesting a rifting phase;a slow tectonic subsidence happened during Dongying period

suggesting a transitional phase of rifting-subsiding;Guantao-Minghuazhen period was a subsiding phase.The comparison of the three boreholes of the three tectonic belts situated on the same measuring line indicates that Qidong tectonic belt in the south part has the maximum amount of tectonic subsidance;Baidong tectonic belt in the middle is secondary and Xingang tectonic belt in the north part has the minimum amount.The tectonic subsidence trend reflects the extensional amount trend.