伸展方式对伸展构造形成特征影响的相似模拟

本文分析了三种不同基底伸展方式、具有膝状边界形态的砂箱实验模型 ,结果表明基底伸展方式的不同可以导致伸展盆地平面变形面貌和剖面构造样式上的显著差异。伸展方式对于凹形边界和凸形边界具有不同的影响。凹侧主动伸展模型在凹形边界附近形成平行边界复合方向的断层 ,在凸形边界附近则形成平行边界走向的断层。凸侧主动伸展则趋于在两侧边界附近形成近于垂直伸展方向的断层。由此可见 ,可能借助伸展盆地的断层平面变形面貌判别主动分离块体。

ANALOGUE MODELING OF INFLUENCE OF STRETCH MANNER ON GEOMETRIES OF EXTENSIONAL STRUCTURES

Three sandbox models of kink shape boundary and with different stretch manners are conducted in this study. The results indicated that differences of plane appearance and sectional pattern of structures in an extensional basin might be caused by different stretch manner in its base. Stretch manner has different influences on concave boundary and convex boundary of a model. In the model actively stretched by side of concave boundary, orientation of the faults formed near concave boundary is nearly parallel to complex direction of the boundary, and that of the faults formed near convex boundary is nearly parallel to direction of the boundary. But in the model actively stretched by side of convex boundary, orientation of faults formed near the two boundaries is almost perpendicular to the directions of boundaries. It is possible that active stretch block in an extensional basin can be distinguished according to its plane appearance of structures.