松辽盆地北部浅部基底推覆伸展作用的地震学证据与地质意义

已经利用近垂直反射地震叠偏剖面得到太平洋板块西向俯冲远程应力场形成上部地壳滑脱断裂的证据，在此基础上，利用油气地震叠偏剖面发现中远程的蒙古—鄂霍茨克缝合带、远程的太平洋板块西向俯冲带在松辽盆地滨北地区浅部基底共同作用形成的逆冲推覆断裂系统.该断裂系统基本呈双向形式，纵向与横向上表现出不均匀的强度，向西逆冲推覆的断裂系统厚度范围可达到约3~4 km，向东的断裂系统厚度范围可达到约1~2 km，断裂系统组构比较复杂.经过对控盆断裂孙吴—双辽断裂两侧地球物理场分布特征的分析，认为松辽盆地浅部基底的逆冲推覆断裂系统是叠加在孙吴—双辽断裂之上的新的断裂系统.考虑到蒙古—鄂霍茨克缝合带在远离1000多公里之外所产生的内蒙古阴山—燕山大型逆冲推覆断裂带以及松辽盆地的区域构造位置，认为在松辽盆地南部和滨北地区孙吴—双辽断裂构造线之外也应该存在浅部基底内的逆冲推覆断裂.

Seismic evidence and geological significance of thrust-extension structure in upper basement of north Songliao Basin

Nearly vertical seismic reflection stacked migration section study has proved that the distant stress field formed by the westward subduction of Pacific plate lead to the detachment of upper crust. In the upper basement of Songliao basin in Binbei area, the thrust-nappe fault system was controlled by middle-distance Mongolia-Okhotsk suture zone and distant westward subduction of Pacific plate together. The fault system shows bidirection and the asymmetric intensity shows in longitudinal and transverse directions. The thickness is 3~4 km and 1~2 km for the westward thrust-nappe fault system and the eastward fault system, respectively. The structure of fault system is complex. According to the distribution of geophysical field along both sides of the Sunwu-Shuangliao fault which controlled the evolution of the basin, the thrust-nappe fault system in the upper basement of Songliao basin was overlapped on the Sunwu-Shuangliao fault. As we know, the Mongolia-Okhotsk suture zone has formed the huge Yinshan-Yanshan thrust-nappe zone more than 1000 km far away from the suture zone. Taking this and the regional tectonic environment of Songliao basin into account, a thrust-nappe fault system should be formed in the south Songliao basin and the Binbei area beyond the Sunwu-Shuangliao fault system.