关键词: 走滑断裂, 拉分盆地, 郯-庐断裂营潍段, 莱州湾凹陷

Abstract: This paper points out distinctly for the first time that Laizhouwan Sag is a pull-apart sub-basin that is related to the strike-slipping of Yingkou-Weifang fault in the Cenozoic. Yingkou-Weifang fault is a segment of Tan-Lu fault system,we estimate its wrench displacement in the Cenozoic is about 40km. Utilizing balance cross section technique,we calculated the pull-apart extensional length in Laizhouwan Sag is about 5～7km,extensional rate is about 2000. Further more,based on the analyses of the characteristics of fault development and the subsidence history,we find that Laizhouwan Sag had been experienced three structural evolution stages-those were the initial strong rifting stag during Eocene,the tender rifting but stronger down-warp subsidence stag during Oligocene and the tectonic rejuvenation stage under the background of thermal subsidence during Neogene. Finally,the continental pull-apart extension model in the study area has been disussed. And also points out that the strike-slip belts on the eastern and western sides of the sag and the central structure belt in the sag are the good oil and gas potential exploration zones.

Key words: strike-slip fault, pull-apart basin, Yingkou-Weifang fault, petroleum exploration significance, Laizhouwan Sag