蒙脱石伊利石化的水热实验模拟

Transformation of montmorillonite illitization based on hydrothermal experiments

以蒙脱石为初始材料,通过水热实验模拟在不同温度压力条件下蒙脱石的伊利石化过程。利用X射线粉末衍射及X射线荧光光谱、红外光谱和扫描电镜等方法对样品的矿物物相、化学成分、晶体结构与微观形貌等进行分析,其结果表明:(1)蒙脱石至伊利石的转化受温度和压力条件的控制;(2)随着温度和压力的增高,蒙脱石伊利石化沿着蒙脱石-无序伊蒙混层-有序伊蒙混层-伊利石的转化序列进行转化;(3)水热实验模拟表明蒙脱石至伊利石的转化以溶解重结晶机制为主。实验结果不仅有助于了解埋藏与低级变质作用中的蒙脱石伊利石化过程,同时为研究断层活动所致断层泥中黏土矿物的转化及反演断层形成时温度压力条件提供基本参数。

Montmorillonite was selected as the initial material to simulate the transformation process of montmorillonite into illite by hydrothermal experiments in different temperautres and pressures.The mineralogical and chemical evolution,crystal structure and morphology of the clay minerals were analyzed using X-ray powder diffraction(XRD),X-ray fluorescence(XRF),Fourier transform infrared spectroscopy(FTIR)and scanning electron microscope(SEM).The results showed that:①the transformation process of montmorillonite illitization depends on the temperature and pressure;②with the increasing of temperature and pressure,the transformation sequence was from montmorillonite to disordered I/S,ordered I/S,and to illite;③the transformation process mainly involved dissolution and recrystallization mechanism.The experiment is helpful to the understanding of the transformation process of montmorillonite illitization under the condition of burial and very low-grade metamorphism,and provides basic parameters for the transformation of clay minerals contained in fault gouge during fault activity,as well as the temperature and pressure conditions for the inversion of fault formation.