曲折边界斜向裂陷伸展的砂箱实验模拟

SANDBOX EXPERIMENTAL MODELING OF OBLIQUE EXTENSIONAL RIFTING WITH KINK BOUNDARY

根据黄骅盆地边界几何特征简化所设计的 3个砂箱实验模型表明 ,同一裂陷伸展过程可以形成不同走向的正断层 ,基底伸展边界方向的变化可以引起裂陷内部断层走向的变化 .裂陷盆地断层走向受基底伸展边界方向和裂陷伸展方向的共同影响 ,裂陷边界及其附近断层走向主要受基底伸展边界方向的影响 ,裂陷内部、离伸展边界较远部位的断层走向主要受伸展方向影响 .凸形曲折边界可以引起断层转向 ,而凹形曲折边界的复合方向构成对断层走向的控制 .黄骅新生代盆地可能形成于近S—N向的裂陷伸展过程 。

Three sandbox experimental models, designed in line with the simplified geometrical features of the boundary of the Huanghua basin, are discussed. It is indicated that normal faults of different orientations may occur in a single episode of rifting extension. The variation in the direction of basement extension boundary may result in the change in the orientation of the faults inside a rift. The orientations of faults inside a rifting basin are controlled by both the direction of the basement extension boundary and by that of the rifting extension in the said basin. The orientation of faults at or near the rift boundary is mainly dependent on the direction of the basement extension boundary. The orientation of the faults located inside a rift basin or relatively far away from the extension boundary, is mainly dependent on the rifting direction. The convex kink boundary may initiate a change in the orientation of the faults, but the complex direction of the concave kink boundary may control the orientation of the faults. Therefore, the Cenozoic Huanghua basin may have occurred during the approximately S-N_directed rifting process. Its kink shape of extension boundary may have resulted in the various changes in the fault orientation in this basin.