【摘要】 以歧口凹陷高精度大面积三维地震资料的应用为基础,结合前人研究成果,系统分析了歧口凹陷新生代走滑断裂特征及其对盆地发育演化过程的控制。认为,歧口凹陷新生代发育2组3支走滑断裂系,其中羊二庄走滑断裂系为兰聊走滑断裂在该地区的主要走滑分支,而沿岸走滑断裂带应为调节断裂带;沿岸及羊二庄走滑表现为右旋走滑性质,而海河走滑断裂则表现为左旋性质;新生代走滑表现为幕式活动特征,表现为张扭断裂的大量出现,可识别出沙一期及明化镇期2期走滑活动;走滑活动及发育与周边板块活动密不可分,2期走滑活动时限分别对应南海扩张及青藏高原的快速隆升,为太平洋板块、印度板块与欧亚板块的汇聚速度、方向变化所致;走滑断裂将歧口凹陷分割为结构构造特征不同的3个块体,受走滑活动影响歧口凹陷断陷阶段均表现为存在主沉降中心、沉积中心、断裂活动中心等的向NE方向迁移的特点,拗陷阶段表现为沉积速率、断层活动速率等的加速沉降及断层活动强度中心的NE向迁移过程,与典型伸展断陷盆地特征存在明显区别。更多还原

【Abstract】 Based on the newly obtained high resolution 3D seismic data,we analysed the characteristics of strike-slip faults in Cenozoic Qikou sag and its controlling role in basin evolution.There develop two group strike-slip faults with three branches in Cenozoic Qikou sag,the dextral Lankao-Liaocheng strike-slip fault system coastal strike-slip fault zone and Yangerzhuang strike-slip fault zone,and the sinistral Zhangjiakou-Penglai strike-slip fault system Haihe strike-slip fault zone.Characteristics and spatial distribution of Yangerzhuang strike-slip fault zone suggested that the strike-slip fault zone should be the main branch of the dextral Lankao-Liaocheng strike-slip fault system but not the costal branch as another view.One major result of the strike-slip tectonic is the sharp increase in number of extensional faults.The Cenozoic strike-slip tectonic can divided into two episodes of late Shahejie Formation episode and Minghuazhen Formation episode.The strike-slip tectonics originated from the collisions of surrounding plates.The late Shahejie Formation episode movement is corresponding to the opening of South China Sea at about 34Ma,and the Minghuazhen Formation episode movement is corresponding to the Tibet plateau fast uplifting at about 5 Ma.Strike-slip fault zone divided the Qikou sag into three blocks with different structure style.Due to the strike-slip tectonic the evolution of Qikou sag is distinct from classical extensional basin.In the rifting episode,there were several subsidence centers and one main subsidence center,meanwhile the depocenter,the main subsidence center and the fault activity center of different evolution stages migrated toward Northeast.In the thermal subsidence episode,the rate of deposit and subsidence and fault movement sped up,and the intensity center of fault movement migrated toward Northeast.更多还原