Pressure dissolution (Sorby 1908) is the petrologic process wherein minerals dissolve as the result of pressure applied externally to them. Because pressure dissolution leads to a reduction of volume of the rock in which it occurs, it is also called chemical compaction(Lloyed 1977). The product of chemical compaction as fellows:
In limestone-marl aternations, differential compaction happend, in limestone no or rare compaction, but it is common in marl. It is due to the stratified cementation, the more cemented strata resisted further compaction.
photo from Permian South China,Qixia Formation