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选取横跨西湖凹陷的11条典型地震剖面,应用平衡剖面分析技术,计算了西湖凹陷新生代不同构造演化阶段的伸缩率.分析研究表明,西湖凹陷始新统平湖组三四段沉积前处于伸展状态,平湖组三四段至中新统玉泉组沉积时期处于压缩状态,中新统柳浪组沉积至今整体区域沉降.从演化阶段看,始新世中期以前西湖凹陷处于拉张期,始新世中期开始进入挤压期,期间玉泉运动(T30)、花港运动(T20)和龙井运动(T12)3次挤压的强度不断增大.结合凹陷沉积充填结构的分析,西湖凹陷新生代经历了古新世和早中始新世断陷、晚始新世和渐新世坳陷、早中中新世反转和晚中新世至今整体沉降的4个演化阶段.从空间演化上看,不同演化阶段南部和北部伸缩率存在一定的差异,这也是造成西湖凹陷构造南北分块的重要原因.“,”Eleven typical seismic sections were selected from the Xihu Sag to calculate the extensional and compressional rates of the sag in different tectonic evolutionary stages in Cenozoic,by means of the balanced cross section technique.Results suggeted that the Xihu Sag be in an extension state before the 3rd and 4th members of the Eocene Pinghu Formation was deposited,and in a compression state during the deposition of the 3rd and 4th members of the Eocene Pinghu Formation to the Miocene Yuquan Formation,and had remained in an sinking state since the Miocene Liulang Formation up to present.It,in a tectonic point of view,means that the Sag was extensional before the middle Eocene,and changed into compressional since then,and the compressional strength increased successively from the Yuquan movement(T30),to the Huagang movement(T20) and to the Longjing movement(T12).Based on the depositional architecture of the depression,the tectonic evolution of the Xihu Sag could be divided into four stages,namely the syn-rifting stage from Paleocene to middle Eocene,the post-rifting stage from late Eocene to Oligocene,the inversed stage during early to middle Miocene and the sinking stage since Miocene.The tectonic evolution shows some sort of difference between the south and the north of the Sag in different stages in terms of extensional and compressional rates,that might be the reason for the differentiation of structural appearance in the south and north of the Sag.