华北克拉通破坏区最新构造变动起始时间及其变形样式

Through the Neogene - Quaternary stratigraphic correlation, detail stratigraphic division by drilling across the main boundary of the Dachang concealed depression where the high-angle seismogenic fault has cut the paleogene listric faults, re-location of small to moderate earthquakes, their focal mechanism inversion, fitting of the focal faults and partitioning stress field analysis, high-resolution satellite image interpretation at the key tectonic sites, offset landform and geotectonic morphology measurements and seismotectonic map or map compilation of active faults and basins in the North China, division of active blocks and their kinematic characteristics, initiation time of the latest tectonic movement, crustal deformation style and vertical and horizontal partitioning tectonic characteristics in the break-up areas of the North China Craton will be well studied. This study will help us to discuss if the latest crustal deformation in the break-up areas of the North China Craton is under extension, compression or shearing (strike-slip faulting) environment, to study earthquake fault geometry and then to build a regional seismotectonic model, which is closely related to present devastating earthquake occurrence, and give a tectonic linkage between the latest tectonic deformation style and the craton break-up in the North China. Also this study will provide an evidence in Neotectonics to judge whether or not the break-up of the North China Craton has continued into the early Cenozoic.

通过对华北克拉通破坏区区域新近纪-第四纪地层对比、大厂隐伏凹陷新生代断层世代交替的钻孔探测、大地震震源区中小地震重新定位、震源机制反演、震源断层拟合和分区应力场分析、关键构造部位高分辨率卫星影像解译、断错地貌和构造地貌测量、地震构造图编制等研究工作，给出华北克拉通破坏区最新一期构造变动起始时间、变形样式和分区构造运动（水平与垂直运动）特征，进行华北及其邻区活动块体划分，讨论华北克拉通破坏区地壳伸展、挤压压缩或剪切走滑环境归属问题，有针对性地研究地震断层几何学特征，构建区域地震构造模型，建立与现今破坏性地震密切相关的最新构造变动样式和分区特征与克拉通破坏之间的某种构造连接，为华北克拉通破坏是否可能延续到新生代早期提供新构造运动依据，也为深刻理解华北克拉通破坏区大、特大地震频发机理提供一种可能的力学机理解释。

通过对夏垫断裂两侧钻孔岩芯的详细孢粉分析、古地磁测试和年代学编年研究，厘定大厂隐伏凹陷主控边界断裂世代交替发生的时间，结合对鄂尔多斯块体周缘大青山地区的不整合剖面的年代学研究，初步理解了华北克拉通最新构造变动起止时间。在收集、整理华北地区现有破坏性地震震源机制解，GPS形变场数据，以及小震重新定位资料，对华北地区的现今应变状态有了清晰的认识。对华北构造区典型断裂，南口-孙河断裂带、五台山北麓断裂，尤其郯庐断裂带，开展了高分辨率卫星解译和空间分布特征、地质填图、古地震探槽开挖和断错地貌的实测和编年，对断裂的几何学、运动学参数及滑动习性参数有了更可靠的数据支持。利用低温热年代学方法，初步对五台山晚新生代活动历史进行了研究。在上述研究的基础上，综合理解了华北克拉通破坏区最新构造变动样式和分区构造特征，为理解华北克拉通破坏区大地震频发机理提供解释。