扬子地块北缘滑脱系统结构单位的组成与特征

STRUCTURAL ELEMENTS OF THE DECOLLEMENT IN THE NORTHERN MARGIN OF YANGZI MASSIF AND THEIR FEATURES

扬子地块北缘滑脱系统由一些发生于不同深度层次的滑脱面(带)及其之间的变形或未变形的岩石地层单位组成。鄂西北南化塘一带已确定出滑脱构造由三个主滑脱面(带)与下部强变形带、中部褶皱层及上部层滑岩片构成。这些结构单位各自都具有一定的岩石地层组成和变形构造形迹组合,并且自下而上虽然变形机制均以顺层剪切为主,但变形的性质与变形强度都有明显的变化。

The decollement in the northern margin of the Yangzi Massif is composed of the same decollement surfaces (or zones) formed at different levels and the deformed or undeformed strata among the surfaces. Three main decollement surfaces (or zones) and low-strong deformation zone, middle folding layers and upper bedding slip slabs have been demonstrated in the Nanhua area of the northwest part of Hubei province. Each of these elements has a special lithostratigraphy composition and a special deformational trace assemblage. Though the deformational mechanism is a main bedding shearing. the changes of nature and strength of the deformation are very clear.