断层泥伊利石物理化学特征及其意义

通过X射线衍射和化学分析等方法,研究了云南水电站断层泥中伊利石物理化学特征,结果显示：①伊利石物质的X射线衍射特征为⊿（002）-（001）] ＞8,Ir＞1,BB1 ＜4°,属I＋ISII有序混层,膨胀层小于15％,晶胞参数b0=8.991A,1M多型结构;②K2O的平均含量9.1％变化范围在8.5％-10％之间;③K2O和Fe2O3含量之间为负相关,K2O含量与⊿（002）-（001）] 2θ值呈正相关,而K2O与Ir值呈负相关.上述特征表明该断层泥伊利石是在低温（小于200℃）低压环境下生成.它的形成与断层稳定滑动机制有关.由此推测该断层未来发生大地震的可能性较小.

Characteristics of Illite Minerals in Fault Gouge and Their Geological Implications

The characteristics of minerals,such as illite,etc.in fault gouge from Xiaowan Fault are studied with X-ray diffraction and chemical analysis.The results show that：（1） X-ray diffraction features of illite are ⊿ （002）-（001）] ＞8°,I,＞1,BB1 ＜4°,belonging to orderly mixed layer.Expansive layer accounts are smaller than 15％.The crystal cell parameters b0=8.991 （A）,1M polytype structure.（2） KO2 content varies from 4.18％ to 5.56％.（3） There is negative correlation exists between K2O and Fe2O3.There is a positive correlation between ⊿ （002）-（001）] and K2O,but negative correlation exists between K2O and Ir.All of characteristics suggest that illite was formed in the environment with low-temperature and low-pressure,which is related with the low level of fault activity and low probability of strong earthquake occurrence in future.