中国中西部前陆冲断带构造演化及变形特征

前陆冲断带可以分为3种基本类型:弧后前陆型、周缘前陆型和再生前陆型冲断带。相对国外典型前陆冲断带,中国中西部前陆冲断带在构造演化和变形方面具有独特性,属于再生前陆型冲断带,普遍经历了两期逆冲构造变形、或者"伸展-挤压-伸展-挤压"多期构造变形的叠加。中国中西部的再生前陆冲断带多具有"分带、分段和分层"的结构特征,表现出以主干断裂为界往往可以划分为若干个冲断变形带,沿走向方向表现为几个在构造变形上具有明显差异的变形区段,在垂向上由于滑脱层的发育表现出不协调的分层收缩、上下叠置的变形特征。

Evolution and deformation characteristic of the fold-thrust belts in the Central and West China

The fold-thrust belt could be distinguished into three types which are back-arc fold-thrust belt, peripheral fold-thrust belt and rejuvenated fold-thrust belt. The rejuvenated fold-thrust belts were widely developing in the foreland of the Central and West China. Uniqueness on evolution and deformation in relative to the classical fold-thrust belts, rejuvenated fold-thrust belts in the Central and West China were generally undergone either two periods of thrust deformation or multi-period alternation of "extension-compression-extension-compression" tectonic settings. The deformation characteristic can be concluded as "zonation, segmentation and decollement". The thrust belt can be divided into several zones parallel to the strike, and several segments with different characteristic of deformation perpendicular to the strike. Because of detachment layer, the thrust belt can also be divided into several deformation layers.