北京云蒙山变质核杂岩大水峪韧性剪切带的应变特征及构造意义  

Strain characteristics and tectonic significance of Dashuiyu ductileshear zone in Yunmengshan metamorphic core complex, Beijing

作　　者：赵腾格 侯泉林 石梦岩 丁林[1,3] ZHAO TengGe;HOU QuanLin;SHI MengYan;DING Lin(Key laboratory of Continental Collision and Plateau Uplift,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Key Laboratory of Computational Geodynamics,Chinese Academy of Sciences,Beijing 100049,China;Center for Excellencein Tibetan Plateau Earth Sciences,Chinese Academy of Sciences,Beijing 100101,China;Institute of Resources and Environment,Henan Polytechnic University,Jiaozuo 454150,China)

机构地区：[1]中国科学院青藏高原研究所大陆碰撞与高原隆升重点实验室,北京100101 [2]中国科学院大学地球与行星科学学院中国科学院计算地球动力学重点实验室,北京100049 [3]中国科学院青藏高原地球科学卓越创新中心,北京100101 [4]河南理工大学资源环境学院,焦作454150

出　　处：《岩石学报》2021年第8期2483-2501,共19页Acta Petrologica Sinica

基　　金：国家重点研发计划深地资源勘查开采重点专项(2016YFC0600401)资助.

摘　　要：北京云蒙山变质核杂岩东南缘的大水峪韧性剪切带是认识云蒙山变质核杂岩构造演化的关键。本文通过变形温度区间估算、有限应变测量以及运动学涡度计算等手段对大水峪韧性剪切带的应变特征进行了系统分析。长石石英温度计与EBSD石英组构分析结果表明剪切带的变形温度区间为480~650℃。剪切带南西段的变形温度自北向南逐渐降低,北东段的变形温度由岩基向断层方向先降低后升高。有限应变测量结果指示剪切带的变形整体经受压扁作用为主,南西段的压扁程度与韧性位移量均大于北东段。运动学涡度的计算结果表明剪切带在形成过程中主要受纯剪切控制。南西段的运动学涡度自北向南逐渐增大,北东段的运动学涡度由岩基向断层方向先减小后增大。据此认为岩浆作用是导致云蒙山变质核杂岩形成的主导因素,大水峪韧性剪切带北东段的拆离过程可能受到了东侧岩体的阻挡。The study of the Dashuiyu ductile shear zone on the southeastern margin of the Yunmengshan metamorphic core complex in Beijing provides a new basis for understanding the tectonic evolution process of the Yunmengshan metamorphic core complex.This paper systematically analyzes the strain characteristics of the Dashuiyu ductile shear zone by means of deformation temperature interval estimation,finite strain measurement and kinematic vorticity calculation and further explores the structural significance of its changes.The results of feldspar quartz thermometer and EBSD quartz fabric analysis show that the deformation temperature range of shear zone is 480~650℃.The deformation temperature of the southwest section of the shear zone gradually decreases from north to south,and the deformation temperature of the northeast section first decreases from the rock base to the fault and then increases.The finite strain measurement results indicate that the deformation of the shear zone is affected by flattening as a whole,and the flattening degree and ductile displacement of the southwestern section are greater than those of the northeastern section.The kinematic vorticity calculation results show that the shear band is mainly controlled by pure shear during the formation process.The kinematic vorticity in the southwestern section gradually increases from N to S,and the kinematic vorticity in the northeastern section first decreases and then increases from the rock base to the fault direction.Combined with the previous research results of Yunmengshan metamorphic core complex,comprehensive analysis shows that magmatism is the dominant factor leading to the formation of the Yunmengshan metamorphic core complex,and the detachment process of the northeast segment of the Dashuiyu ductile shear zone is blocked by the eastern rock mass.

关 键 词：云蒙山 韧性剪切带 有限应变测量 运动学涡度 

分 类 号：P542.33[天文地球—构造地质学] P545[天文地球—地质学]