Microstructural characterizations of three main constituents of mudstone

The aim of this study was to explore the principal contributing cause of the hardened mudstone using microstructural and microchemical evidences. The elemental and morphologic changes in the three separated phases of mudstone were illustrated by using X-ray fluorescence spectrometer (XRF) and scanning electron microscopy (SEM)/energy-dispersive X-ray analysis (EDAX) techniques. The results of XRF analyses for the isolated phases indicated that the each main composition of separated by using textural fractions is still the presence of sand, slit, and clay phases. Moreover, the results of XRF and EDAX analyses obtained a good consistency. Through the SEM/EDAX semiquantitative analyses, it was shown that the amount of Ca decreased with an increase in the amount of clay. Thus, it was suggested that the main contributing cause of the hardened mudstone was attributed to the cementing reaction between calcium species and quartz.