大兴断裂分段性研究

RESEARCH ON THE SEGMENTATION OF DAXING FAULT

冀中坳陷大兴断裂具有分段性 ,且各段特征存在差异。根据大兴断裂展布方向的不同 ,将其划分为北段(NNE向 )、中北段 (NE向 )、中南段 (近EW向 )和南段 (近NS向 ) 4段。各分段断层的结构、形态、伴生构造、活动时间及对沉积作用的控制等都存在较明显差异。其中 ,NE走向段对整个廊固凹陷的构造特征具控制作用。各段的结合部位 ,构造特征各具特色。大兴断裂作为控制凹陷的边界大断层 ,在早第三纪相同的拉张应力场作用下 。

Daxing fault in Jizhong sag is characterized with segmentation and variations for each segment. The fault, according to its extending trends, can be divided into four segments namely; north segment(NNE trend), mid-north segment(NE trend), mid-south segment (near EW trend) and south segment(near NS trend).Each segment has a distinctive difference of its own in fault geometry, associated structures, active age and the sedimentation control etc. Especially, the NE trend segment controls the structural characteristics of the whole Langgu sag. The structural character varies in the hinge area between two segments. As a boundary fault controlling the sag, the evolution of Daxing fault has intrinsic correlations with each segment due to the same effects of extensional stress field in the early Tertiary.