渤海湾盆地晚中生代-新生代伸展和走滑构造及深部背景

渤海湾盆地是一个在早白垩世被动裂陷盆地基础上发育起来的新生代主动裂陷盆地, 走滑作用贯穿始终, 特别是在兰聊-盐山断层以东, 使这个裂陷盆地具有鲜明的走滑特征。伸展和走滑作用此消彼长, 伸展构造和走滑构造相互叠加、转换, 垂向上相互叠置、交切, 并由此导致变换带的产生。晚中生代以来太平洋板块向欧亚板块俯冲的方向和速度变化、后撤以及板片窗效应、中始新世印欧板块碰撞导致的地幔上涌是控制盆地形成的深部背景, 郯庐断裂带早白垩世强烈的左行走滑、古新世-早始新世弱的左行走滑以及中始新世后的右行走滑活动也深刻地控制和影响着盆地的发育, 盆地内晚中生代-新生代的伸展和走滑构造的演化则是其浅部响应, 并由此控制着岩浆活动以及油气生成、运聚和分布的时空迁移。

Late Mesozoic to Cenozoic extension and strike slip structures and deep background of Bohai Bay Basin

The Bohai Bay Basin is a Cenozoic active rift basin superposed on the Early Cretaceous passive rift basin with strike slip action run though thoroughly, especially in area east of the Lanliao-Yanshan strike slip fault. So this rift basin shows significant strike slip characteristics. The extension and the strike slip action increased and decreased each other, made the extensional structure and strike slip structure superpose, transfer and cut. Meanwhile, the transfer zone in the basin was also generated. The changes of the Pacific-Eurasian plate subduction direction and velocity since～140 Ma, the roll back of the Pacific plate, and the slab window effect, together with the Middle Eocene Indo-Eurasin plate collision resulted in the asthenosphere mantle upwelling, are the deep back ground of the basin formation. Also the strike slip of extensive sinistral in Early Cretaceous, weak sinistral in Paleocene-Early Eocene, and dextral in Middle Eocene of the Tanlu fault profoundly controlled and influenced the basin evolution. The evolution of the extension and strike slip structure is the shallow response of the deep background, which controlled the spatiotemporal migration of magmatism, oil-gas formation, accumulation and distribution in basin.