武功山北缘剥离断层、近水平韧性剪切带与伸展构造

THE DENVDATIONAL FAULTS, HORIZONTAL DUCTILE SHEAR ZONE AND EXTENSIONAL TECTONICS ALONG THE NORTHERN EDGE OF WUGONGSHAN

武功山北缘的伸展构造结构完整,系由以脆性变形的上拆离盘及近水平的韧性剪切带为代表的变质核杂岩体所组成。上拆离盘组成于一系列的北倾犁式正断层系及拉张断陷盆地;变质核杂岩体的岩石以舌状—饼状褶皱、片理化、拉伸线理及条带状糜棱岩等近水平的韧性剪切变形为其特征。根据由伸展构造所控制的拉伸断陷盆地的沉积物时代来推测,武功山北缘的伸展构造可能发生于印支运动晚期。

Along the northern edge of Wugongshan, extensional tectonics are well developed, which are consisted of metamorphic core-complex (horizontal ductile shear zone). The hanging wall, is consisted of a series of listric normal faults. In footwall, the rocks in metamorphic core-complex are characterized by tongue- like and cake-like folds, schistosity, stretching lineation, striped mylonite and horizontal ductile shear zone. On the basis of evidence about the time of deposits in extension block basins, it is inferred that the extensional tectonics in this area were developed in late Indosinian stage.