Abstract: In this paper,characteristics of illite in fault gouges are studied by SEM, XRD and chemicalanalysis.The study shows that illite belongs to I ＋ISIl structure;expansibility takes approximately 15%; IMis of multiple paterns interlayer positive ions 2Ca＋Na＋K≈l;b₀ value of illite is 8.993Å in fault gouge at Xiaowan,which show that mechanisms of fault movement in Xiaowanare of low pressure and temperature(<200℃)。

Key words: Clay mineral, IIIite, X－ray diffraction, Fault gouge, Yunnan

摘要： 根据扫描电镜观察、X射线衍射和化学分析,研究断层泥中伊利石矿物的特征。研究表明,小湾断层泥中伊利石属I+ISII结构,膨胀层约占15%,IM多型,层间阳离子2Ca+Na+K≈1,伊利石的b₀值等于8.993Å,这些参数反映了小湾断层活动的机制为低压、低温(<200℃).

关键词: 粘土矿物, 伊利石, X射线衍射, 断层泥, 云南