中国大陆东部盆地构造动力学分析

在中国大陆东部地区，松辽、渤海湾和苏北等—系列中、新生代大中型含油气盆地与郯庐断裂具有密切的时空关系。郯庐断裂活动是邻近地区断裂变形、深部物质作用、岩石圈减薄、岩浆作用以及盆地形成和演化的主要控制因素。断裂活动和盆地动力学过程可以分为３个阶段。①在印支至早燕山运动期间，由于太平洋板块向北西俯冲，郯庐断裂发生大规模左行压扭活动。在松辽地区，派生的应力场使早期的地壳断裂成为郯庐断裂的分支，并发生张剪变形；在渤海湾和苏北地区，早期的两组剪切断裂联合成北凸的弧形断裂。由于断裂的触发与减压作用，地壳上部进一步张裂，形成断陷盆地。②从晚侏罗世开始至早白垩世，太平洋板块的俯冲作用时强时弱，郯庐断裂压扭与拉张裂陷交替进行。同时，由于重力均衡和深部幔隆的收缩作用，使松辽盆地整体下沉，渤海湾和苏北地区仍是幔隆和断陷盆地形成时期。③新生代期间，郯庐断裂分段活动，由于印度板块与欧亚板块的强烈碰撞效应，渤海湾、苏北地区和郯庐断裂带南段共同受到北西—南东方向的伸展变形，地幔再次拱升，渤海湾和苏北盆地形成

GEODYNAMICS OF SEDIMENTARY BASINS IN EASTERN CHINA

There are some oil|bearing basins along the Tanlu fault and its both sides, such as Songliao basin, Bohai Bay basin and North Jiangsu basin, which are parts of Tanlu fault system. According to the characteristics of tectonic geometry, kinematics and dynamics of the basins, the movement of Tanlu fault controlled the rise of upper mantle and the formation of the basins in Mesozoic|Cenozoic. The movement of Tanlu fault and the formation of the basins can be divided into three stages. During T|J-2, Pacific plate subduced towards north|west direction. The left|lateral compressive movement of Tanlu fault was caused by the subduction, and some derivative faults formed. The upper mantle uplifts were induced in the areas of Songliao, Bohai Bay and northern Jiangsu. Then the upper crust was extended, and many small rift basins also formed. The subduction and collision between Pacific plate and Eurasian plate changed into intermittent movements during J-3|K-1, and Tanlu fault and its both sides were mainly extended. The depressed basins of Songliao, Bohai Bay and North Jiangsu were developed in that period, and several petroleum systems formed at the same time in these basins. Because the direction of subduction of Pacific plate changed into south|west direction during Tanlu fault right|lateral compressive movement, extensional movement happened during K-2|N. Then Bohai Bay basin and North Jiangsu basin formed in that period.=