Argilaceous rock is one of the important candidate host rocks for the repository of high-level radioactive waste geological disposal. Geological survey has been conducted on the clay formations in Nanbaxian area

northwest portion of Qaidam in Qinghai Autonomous Region. The initial results indicated that the argillaceous rocks such as clays and siltstone were widely extended in the study area. Petrology and mineralogy studies by X-ray diffraction analysis demonstrated that the clays are mainly composed of quartz

calcite

mica

kaolinite and illite with the politic texture and compact structure. The results of this study showed that it is necessary to conduct further studies on the clay formations in Nanbaxian area as the possible host rocks for high-level radioactive waste geological disposal repository.