滇西主高黎贡韧性剪切带糜棱岩形成时限的初探

构造形成时限的研究,可以为相关地质事件提供重要的制约条件。本次工作利用应变速率法进行分析,以主高黎贡韧性剪切带长英质糜棱岩为实例,通过石英自由位错法测得其差异应力130.69MPa,进而得出应变速率为2.906×10-13s-1;利用质量等比线法分析得出其体积因子为0.7314;进而可以求出构造形成时限为3.41万年。这一时间段的确定,为特提斯构造系形成时限的研究,给出了一项可供参考的数据,同时也表明应用应变速率法研究构造形成时限是可行的。

A PRELIMINARY STUDY ON THE DURATION OF STRUCTURAL DEFORMATION OF MYLONITES IN MAIN GAOLIGONG DUCTILE SHEAR ZONE IN WESTERN YUNNAN

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.