关键词: 伸展构造, 拉伸量, 平衡剖面, 犁式正断层, 压实校正

Abstract: The crust of east China has been affected by extensional stress since the Mesozoic-Ceno-zoic. Ectensional structures developed widely in the Jiyang depression and its surroundings.After analysing outcrop sections and seismic profiles,we can sum up the characteristics of extensional strucyures and construct a geometric model of extensional structures in the studyarea. Not only can a series of parameters related to extensional activities be acquired,but alsocan the restored sturctural sections in different geological ages be obtained by using thd basicmethod of balanced-section based on the model,In terms of the calculation of two profiles inthe Yangxin sag of the Jiyang depression,the analysis results ane:the last rifting stage ofthe sag began form the second member of thd Kongdian lormation,the rifting actibity wasstrongest during the first member of the Kongdian formation and the lower part of the foruthmember of the Shahejie formation,tended to relax form the upper part of thd fourth memberof the Shahejie formation,and became much weaker in the second member of the Shahejieformation and thd Dongying formation which were thd transition stage form riftiong to sub-siding.