饶阳凹陷构造成因分析

Analysis of Structural Genesis in Raoyang Sag

饶阳凹陷是一个东断西超的新生代箕状断陷,内部发育了一系列伸展构造和走滑构造,伸展构造是主体。统计各层位四级断层的走向得出,古近纪由早至晚伸展方向由近东西向到北西-南东向再到近南北向顺时针旋转。右行走滑构造也很明显,表现为雁列构造、帚状构造、花状构造、主断裂尾部构造等主断面陡倾,主要形成于沙三段至东营组沉积期。马西、河间、留路等主控断层的坡坪式形态和伸展活动,导致了自东向西依次为断裂构造带、主洼槽带、中央潜山带、次洼槽带、斜坡的规律性分布。北部主滑脱面深度大,为基底掀斜翘倾区;中部主滑脱面深度较大,为基底断弯区;南部主滑脱面深度较小,为盖层滑脱断褶区。

Raoyang sag is a Cenozoic halfgraben-like fault depression with faulting in the eastern part and overlapping in the western part,in which a series of extensional and strike-slip structures are developed,dominated by extensional structure.The statistics of 4th-grade faults strikes in each horizon show that they trend from near EW to NW-SE and to near SN in the Early to Late Paleogene by turn clockwise.Dextral strike-slip structure assumes such main fault plane steep-tilting styles as enechelon,brush,flower structures and main fault tail structures,etc.,which are primarily formed in the third segment of Shahejie period and Dongying period.The ramp-flat patterns and extensional activities of master faults like Maxi,Hejian and Liulu faults result in regular distribution of the fault belt,major hollow groove belt,central buried hill belt,sub-swamp groove belt and slope from east to west direction.The main detachment plane with big depth in the north is basement-tilted area,the central part with medium depth is basement fault-bend area,and the southern part with small depth is cap rock-slip fault-fold area.