华北沧东断裂的构造特征

地质和地球物理资料表明 ,沧东断裂为发育于上地壳的上陡下缓的铲状断裂 ,断面于 10km深处的上地壳底部变为近水平的拆离滑脱面。沧东断裂经历了中、新生代两个裂陷旋回 ,开始形成于晚侏罗世 ,此时为正断裂性质 ,早白垩世末期的燕山运动使断裂反转为逆断裂 ,并有一定的左旋走滑 ,形成正花状构造。早第三纪始新世时在中生代断裂的基础上改造成为正断裂 ,控制了黄骅坳陷下第三系的分布。早第三纪为断裂主要活动时期 ,塑造了现今沧东断裂的主要形态 ,断裂不同区段的产状、发育历史和活动强度表现出鲜明的分段性。晚第三纪以来断裂活动微弱。从浅层地震勘探结果看 ,沧东断裂晚更新世以来基本不活动 ,不是活动断裂

STRUCTURAL CHARACTERS OF THE CANGDONG FAULT IN NORTH CHINA

The latest geological and geophysical data show that the Cangdong fault is a listric fault in the upper crust. The plane of the fault becomes a detachment plane at the 10km depth in the crust. The Cangdong fault has undergone two rifting processes in Mesozoic and Cenozoic time. It formed in late Jurassic as a normal fault, and became a thrust fault by the end of early Cretaceous. It was a normal fault in Eocene, evidenced by the Mesozoic structure, and controlled the distribution of stratum of early Tertia