摘要
通过对大量地震剖面的重新解释,并结合盆地的钻探资料及前人研究成果,揭示了冀中坳陷中区中新生代以来先后经历了:①燕山中晚期(J3-K1)与阜平变质核杂岩形成有关的热力伸展,变质核杂岩拱升隆起导致侧向伸展,太行山东缘拆离断层发育并在其下降盘形成同期断陷盆地(保定凹陷);②古近纪(E)区域应力伸展,太行山东缘断裂及其下降盘的保定凹陷具有明显的继承性,并有"早盛早衰"的特点。而中区东部边缘断裂及其控制的沉积洼槽主要发育于该阶段,断裂强烈活动时间相对晚,但持续时间铰长;⑧古、新近纪之间(N／E)重力伸展,区域不均衡隆升导致饶阳凹陷南部发生大型重力滑覆构造,其运动轨迹类似昆虫前行时的"褶曲蠕动",与经典的重力滑动构造模式有所不同。三期不同性质、不同类型的伸展作用有机相联,彼此影响,并进一步探讨了各类伸展构造的个性特征、形成演化及其盆山耦合的响应关系。
Based on the interpretation of the seismic profiles in the middle Jizhong depression, it is pointed out that the area underwent three types of extension since the mid-Mesozoic, that is, heat doming extension, stress extension and gravity extension. The heat doming extension related with the Fuping nuclear complex took place in the Taihang Mountains in the middle-late Mesozoic. Doming of the nuclear complex lead to lateral extension and detachment faults were developed on the east margin of the Taihangshan Mountains to form a contemporaneous down-faulted basin (Baoding depression) in the foot wall. It is well known that the Bohai Bay Basin came into a stress extension stage in the Eogene, during which the detachment fault and normal fault are two types of growing faults. The former dips gently in shallow layers, but steeply in deep layers of the crust and becomes a horizontal ductile shear zone at the bottom, expressing strongly horizontal extension, whereas the latter has a small extension. A large-scale detachment structure was distinguished in the south area of the Raoyang depression. It is bounded by the Cangxi fault in the east, the Lixian slop in the west, the north Liulu fault in the north and the Hengshui fault in the south. The area is near 2000 km2. This took place due to gravity gliding after the unbalanced uplifting of the Cangxian bulge at the end of the Eogene. This structure is characterized by clear detachment faults, two different deformation systems, as well as the front edge and back edge. The gliding track in the area is like a crawl tract of insects. This is a new gravity gliding model. The three types of extensional structures are connected to each other, influence each other, and there are clear coupling relationships between basins and mountains.
出处
《地质论评》
CAS
CSCD
北大核心
2004年第5期484-491,共8页
Geological Review
关键词
中新生代
复合伸展构造
地震剖面
热力
应力
重力
extensional structure
heat
stress
gravity
Meso-Cenozoic
middle area of the Jizhong depression
