Construction Styles, Distribution Features and Genetic Dynamics of the Paleogene Sequence Boundaries in Jiyang Depression
济阳坳陷古近系层序界面构建样式、分布特征及其成因动力学分析

Under the control of tectonic episodes,multilevel sequence boundaries were developed from early to late Paleogene in Jiyang Depression,which are called Tr,T7,T6',T6,T4,T2',T2,T1' and T1,respectively.According to the contact relationship of strata and the definition of sequence boundary,the authors have divided for the first time the sequence boundaries into six genetic construction styles,i.e.,the onlap/truncation construction style,the parallel/truncation construction style,the onlap/parallel construction style,the onlap/toplap construction style,the parallel/parallel construction style,and the conformity construction style.In this paper T6'and T2' were taken as examples,below or above which stratigraphic and lithologoic traps are fairly developed.The authors analyzed the dynamic factors responsible for the differences in the construction styles of the sequence boundaries.The results show that there are two genetic dynamics factors controlling the differences of sequence boundaries:one is the migration and the differences of time and intension of fault activities,and the other is the migration of tectonic depocenters and the differences in tectonic subsidence extent.It is very important for geologists to identify stratigraphic and lithologic traps in Jiyang Depression,which are usually controlled by different construction styles of Paleogene sequence boundaries,as evidenced by the analysis of construction style differences and genetic dynamics.