A PRELIMINARY STUDY ON THE DURATION OF STRUCTURAL DEFORMATION OF MYLONITES IN MAIN GAOLIGONG DUCTILE SHEAR ZONE IN WESTERN YUNNAN
WU Xiaoqi, LIU Deliang, LI Zhensheng and YANG Qiang (School of Earth and Space Sciences, University of Science & Technology of China, Hefei, Anhui 230026, China)
Study on duration of structural deformation can offer important information on restriction conditions to correlative geological events. In this paper, the authors took felsic mylonites from the main Gaoligong ductile shear zone as an example to analyze the duration by the strain rate method. The differential stress of the mylonites is 130.69 MPa based on the free dislocation density method of quartz, and the corresponding strain rate is 2.906×10 -13 s -1 . The volumetric factor is 0.7314, as was deduced by the isocon method, and the relevant duration of structural deformation of mylonites in the main Gaoligong ductile shear zone is 3.41×104a. This duration could be the reference data for further study about the whole tectonic system of Tethys, and can demonstrate the feasibility in studying the duration of structural deformation by the strain rate method.