东天山-北山造山带中大型韧性剪切带属性及形成演化时限与过程

Age and tectonic evolution of ductile shear zones in the eastern Tianshan Beishan orogenic belt

塔里木盆地北缘的东天山-北山造山带中发育多条近E-W走向的大型韧性剪切带,它们构成了造山带中不同地体单元的主要边界,是碰撞造山及造山后的产物。本文在野外调查基础上,通过微观/宏观构造、几何学/运动学/动力学/年代学相结合的研究、厘定了东天山北山造山带中的7条大型韧性剪切带,阐述了剪切带的延伸、规模、剪切变形特征、变形条件以及形成与演化时限。并讨论了这7条不同类型韧性剪切带的形成过程以及东天山和北山古生代造山过程中所起的重要作用。

Large scale ductile shear zones with east-west trending have been recognized in the eastern Tianshan-Beishan Paleozoic orogenic belt along the northern margin of Tarim Basin. They constitute main boundaries between different tectonic units, are considered as the result of the collisional or postcollisional orogenic event. Based on field work, combining with micro-macro structural and geochronological data, seven large scale ductile shear zones were determined, and their extension scale, shear deformation characteristics, deformation conditions, formation time were constrained. The formation process of the ductile shear zones and their roles played in the Paleozoic orogeny of the eastern Tianshan-Beishan orogenic belt were discussed.