地质论评2018，Vol.64Issue(2)：378-391,14.DOI:10.16509/j.georeview.2018.02.006
东秦岭卢氏地区奥陶系陶湾群的变质变形特征及形成环境分析
An Analysis on Metamorphic and Deformation Characteristics and Formation Environment of the Ordovician Taowan Group in Lushi Area, Eastern Qinling Mountains
摘要
Abstract
Objectives:The Taowan Group linearly distributes on the north side of the Luonan— Luanchuan fault zone and with quite different deformation characteristics and attitude of rocks in the east and west sections.Three structural profiles in Lushi area in the central the Taowan Group are choose as research objects,the deformation characteristics and why the attitude changes in different sections are studied.Methods:The detailed observation of structural profiles,measurement of foliation and lineation of mylonite,microstructure,paleotectonic stress field and geochronology analysis are used to study the Taowan Group.Results:The results show that the deformation mechanism of carbonate mylonite of the Taowan Group is a subgrain rotation type to high temperature boundary migration dynamic recrystallization.The kinematic characteristics of the shear zone are characterized by northward subduction and sinistral strike slip.The ductile deformation characteristics are consistent with the Luonan—Luanchuan fault zone in south side,and it is characterized by strong deformation near the fault zone and weak deformation far away from the fault zone.There are two groups of stress field directions,NE—SW direction and NW—SE direction.The NE—SW compressional stress may produced by subduction of the Kuanping group.However,the NW—SE stress may due to the influence of the Pacific plate.The geochronology indicates that the upper limit of ductile deformation is 386Ma.Conclusions:Carbonate mylonite of the Taowan Group is formed in a strong compression setting cuased by the Qinling micro-continental block oblique subduction to the North China plate.Its metamorphism and deformation is affected by activity of the Luonan—Luanchuan fault zone in Late Caledonian—Early Variscan,and is response to activity of the Luonan Luanchuan fault zone.关键词
东秦岭/卢氏/奥陶系陶湾群/碳酸质糜棱岩/洛南—栾川断裂带/锆石定年Key words
Lushi, Eastern Qinling Mountains/the Taowan Group, Ordovician/carbonate mylonite/Luonan—Luanchuan fault zone/zircon dating引用本文复制引用
韩旭,任升莲,李龙明,李加好,葛粲,宋传中,林寿发,王静雅,李振强..东秦岭卢氏地区奥陶系陶湾群的变质变形特征及形成环境分析[J].地质论评,2018,64(2):378-391,14.基金项目
本文为国家自然科学基金资助项目(编号:41572177,41272213,41573023,41072161,41502193,41272222)的成果.This work was jointly funded by the National Natural Science Foundation of China (No.:41572177,41272213,41573023,41072161,41502193,41272222) and the Doctoral foundation of the Ministry of Education. （编号:41572177,41272213,41573023,41072161,41502193,41272222）
