Structural Properties and Kinematic Analysis of Lianshanguan Ductile Shear Zone in Northern Liao-Ji Rift Zone,Northeastern North China Craton
Chang Ruihong;Li Weimin;Liu Yongjiang;Liang Chenyue;Li Jing;Zhang Li;Liu Xinyue;Fan Wenliang;College of Earth Sciences,Jilin University;Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Land and Resources;Key laboratory for Evolution of Past Life and Environment in Northeast Asia,Ministry of Education;Shenyang Geological Survey Center,China Geological Survey;Changchun Gold Research Institute;
The ductile shear zone is widely discovered in the lithospheric crust,and it contains abundance environmental parameters such as stress,strain temperature and pressure,hence it is an important object for the study of structural analysis,rheology and genetic mechanism.The Liao-Ji rift zone is one of the ancient primitive activities of the North China craton,located in the east of Liaoning Province and North of Jilin Province.The Lianshanguan granitic body,exposed in the Northern margin of Liao-Ji rift zone,experienced complex metamorphic deformation.The mylonitic in the ductile shear zone have obvious dextral strike-slip characteristics with an NWW strike.The observation and analysis of the microstructure of mylonitic reveals that the taconite developed in shear zone is S-SL type,representing a flattening strain.Kinematics vorticity of 0.91-0.97,which are greater than 0.75,indicates that the shearing is formed in the general shear dominated simple shear.In addition,The quartz dynamic recrystallization is obvious,while the mica shows plastic elongation.The quartz c-axis EBSD analysis shows that the quartz fabric is characterized by the middle to low temperature rhomb slipsystem,corresponding deformation temperature of 450-550℃,consistent with a greenschist-low amphibolite facies condition.Based on the previous studies,the forming age of the ductile shear deformation is considered to be the late Early Proterozoic.In conclusion,the Lianshanguan granitic body suffered an initial uplift stage,resulting extension-stretching-decollement within the Liaohe Formation surrounding the granitic body.Subsequently,the studied area was suffered a S-N directing compression,and led to the dextral strikeslip ductile shearing.
【Fund】： 国家自然科学基金重点项目(No.41230206);国家自然科学基金资助项目(No.41672185);; 国家重点研发计划项目(No.2016YFC0600108-02)
【CateGory Index】： P542
【CateGory Index】： P542