巴州坳陷下白垩统—中侏罗统的粘土矿物特征

根据岩石薄片、Ｘ衍射和扫描电镜分析资料，本文研究了巴州坳陷下白垩统—中侏罗统粘土矿物特征，发现粘土矿物分为伊利石、伊／蒙混层和绿泥石三种类型。粘土矿物的类型和含量随深度而变化，形成了伊／蒙混层带、混层迅速转化带和伊利石带。粘土矿物的转化和自生粘土矿物的形成是沉积地层非常重要的成岩变化。

Clay minerals from the Lower Cretaceous to Middle Jurassic strata in the Bazhou depression,eastern Qilian folded belt

The properties of clay minerals from the Lower Cretaceous to Middle Jurassic strata in the Bazhou depression have been explored by means of thin section analysis,X ray diffraction analysis and scanning electron microscopy.The results of the study have contributed to the classification of the clay minerals into three types:illite,mixed layer illite/montmorillonite and chlorite.The types and contents of the clay minerals also vary with increasing buried depth.Three clay mineral zones may be delimited for the Lower Cretaceous to Middle Jurassic strata in the study area on the basis of the evolution of the clay minerals.They are mixed layer illite/montmorillonite zone,rapid conversion zone of mixed layers and illite zone.The evolution of clay minerals and formation of authigenic clay have recorded most important diagenetic changes of sedimentary strata in the study area.