造山带内部的正花状构造

POSITIVE FLOWER STRUCTURES IN OROGENIC BELTS

正花状构造是地壳内一种重要的构造组合样式，其基本结构要素有两个，一是高角度主干走滑断层式剪切带，二是呈背冲形式的叠瓦状逆冲断裂双向变形带．地球上大多数造山带均有正花状构造的发育，且具尺度不变性、不对称性和多层次性，并以走滑及缩短位移场的联合或叠加为特征，反映了剪切及挤压作用的综合变形场，是陆—陆或硅铝壳块体间斜向会聚、碰撞地球动力学体制的必然结果。

The examples of positive flower structures taken from the Wudangshan area, the To ngbai-Dabie area, the western Qinling, the Xuefeng mountains and Himalayas show that the positive flower structure is an important tectonic association style in the crust. A positive flower structure consists largely of a strike-slip fault or shear zone that is present in the central axial zone of the structure and imbricate thrust or fold-thrust deformation belts that are present on eityer side of the strike-slip shear zone. The features of the positive flower structures in the orogenic belts, including a invariance, asymmetry and levels, are reviewed.A geodynamic model is developed rof the formation of these features. In this model, the oblique collision between continental blocks is consided as a geodynamic regime rof the devel opment of the positive flower structures in the Qinling-Dabie Orogenic belt. Such a model may be applied to other collision orogenic belts such as the Alps, the Himalayas, the southern Appalachians internides and the Xuefeng mountains