Explanation

A kind of massive clay rock with complex composition and no obvious bedding joints. It is formed by weakly consolidated clay through extrusion, dehydration, recrystallization and cementation. It is blocky and partially loses its plasticity, and does not immediately expand when exposed to water. Black mud rock often contains organic matter and is a good source rock series. The light colored mud rock produced in the coal measure strata or the Quaternary sedimentary layer can be used as raw materials for ceramics or refractory.

Classification