铁含量对滑石脱水动力学的影响及其地质意义

摘要

在常压下研究了2种不同铁含量滑石的原位X射线衍射高温脱水反应.选取粒径2～5 μm的2种不同铁含量的滑石样品,在常压、空气氛围下进行了同步辐射原位X射线衍射脱水实验.实验结果表明,铁含量高的滑石脱水温度明显偏低,2个滑石样品在常压下发生明显脱水反应的温度相差达127℃以上.滑石在常压下的脱水动力机制为随机成核和生长机制,符合Avrami方程.将实验数据拟合Avrami方程得出:n=1.669.由实验结果可以推测,不同铁含量的滑石脱水深度可能有几十到上百千米的差别,研究铁含量与滑石脱水动力的相关性对于了解俯冲带浅-中源地震的成因机制具有重要意义.%The effect of iron content on the kinetics of talc dehydration was studied with talc of different iron values using in-situ synchrotron X-ray diffraction (XRD).The sample particle size is 2～5 μ m.The air atmosphere synchrotron radiation in situ XRD dehydration experiment was carried out under atmospheric pressure.High content of iron obviously resulted in lower dehydration temperature.The difference of the dehydration temperature of two samples was above 127 ℃.The dehydration of talc followed random nucleation and growth mechanism,and fitted Avrami equation,with n being 1.669.The results suggest that the dehydration of different iron values of talc may occur at the different depths around hundreds of kilometers,so the study was significant to the understanding of the genetic mechanism of earthquakes in the subduction zone.