辽吉裂谷带北缘连山关韧性剪切带的构造属性和运动学分析

发布时间：2018-06-03 20:51

  本文选题：连山关岩体 + 韧性剪切带　； 参考：《地球科学》2017年12期

【摘要】：韧性剪切带在岩石圈地壳中广泛存在,蕴含应力、应变和温压等环境参数,是构造解析、流变学和成因机制研究的重要对象.辽吉裂谷带位于辽宁东部-吉林南部,是华北克拉通重要的古元古代活动带之一.连山关岩体地处辽吉裂谷带北缘,经历复杂变质变形作用,岩体南缘发育NWW向右行走滑韧性剪切带.糜棱岩显微结构观测分析揭示,剪切带内糜棱岩以S、SL构造岩为主,总体呈压扁型应变.运动学涡度值为0.91~0.97,均大于0.75,指示简单剪切为主的变形特征.糜棱岩中云母显示塑性拉长,石英动态重结晶明显,以膨凸重结晶作用为主.EBSD分析结果表明,石英发育中低温菱面组构,对应变形温度450~550℃,暗示糜棱岩形成于低绿片岩相-低角闪岩相.结合前人研究成果,我们认为连山关韧性剪切带可能起源于早元古代晚期.连山关岩体先后经历早期隆起造成的伸展-滑脱作用和晚期与上覆辽河群共同经历的南北向挤压,从而在岩体南缘形成陡倾的右行韧性剪切带.
[Abstract]:Ductile shear zones exist widely in the lithospheric crust and contain environmental parameters such as stress strain and temperature and pressure. They are important objects for structural analysis rheology and genetic mechanism research. Liaoji rift belt is one of the important Paleoproterozoic active belts in North China Craton. Lianshanguan rock body is located in the northern margin of Liaoji rift belt and experienced complex metamorphic deformation. The NWW strike-slip ductile shear zone is developed in the southern margin of the rock mass. The observation and analysis of mylonite microstructure indicate that the mylonite in the shear zone is dominated by SzongSL tectonite, and generally shows flattened strain. The kinematic vorticity is 0.91 ~ 0.97, which is more than 0.75, indicating the deformation characteristics of simple shear. The mica in mylonite shows plastic elongation and obvious dynamic recrystallization of quartz. The results of EBSD analysis show that quartz develops at low temperature rhombohedral fabric, corresponding to deformation temperature 450 ~ 550 鈩，

本文编号：1974141