惠民凹陷南坡北北西向走滑断裂带的发育特征及成因分析

通过对惠民南坡前中生代断裂的平面分布和三维地震剖面特征的分析,识别出了一组在平面上相互平行,在剖面上具有负花状构造的北北西向走滑断裂带。通过对负花状构造的形态及其卷入地层特征的分析,认为该组断裂带经历过两期不同性质的走滑运动,在中生代经历了较强的左行张性走滑,在新生代经历了较弱的右行压性走滑。其演化过程与鲁西地块上北北西向走滑断层的演化过程一致,均属于郯庐断裂区域性走滑作用所形成的帚状构造体系的一部分,郯庐断裂在中生代的左行走滑和新生代的右行走滑是控制其发展演化的主要因素。

FEATURES AND ORIGIN OF THE NNW STRIKE-SLIP FAULTS ON THE SOUTHERN SLOPE OF HUIMIN SAG

Through analysis of the pre-Mesozoic faults in the southern slope of Huimin Sag based on fault distribution ichnography and on 3D seismic sections, it is recognized in this paper that a group of NNW faults are parallel to one another in the ichnography and showing sectional negative flower structures. Analytical results of the shapes of the negative flower structures and the stratigraphic features of the formations indicate that the strike-slip fault group have undergone two different courses of shearing activities, including strong sinistral shearing during the Mesozoic, followed by dextral shearing during the Cenozoic; Evolution of this fault group is similar to that of the NNW-trending strike-slip faults in the Luxi block, as they belong to the same brush fracture system controlled by the slip activity of Tan-Lu fault. It can be deduced that the formation and evolution of the fault group is mainly engendered by the sinistral strike-slip of Tan-Lu fault in the Mesozoic and the dextral strike-slip of Tan-Lu fault in the Cenozoic.