Often high-Mg calcite, sometimes pelletal. Grains may behave in either a brittle or a ductile fashion. Early cementation, common in carbonates, protects grains from compaction. Carbonate rocks and particles are very susceptible to pressure solution . During compaction, strain is localized at grain contacts.
Pressure increases solubility.
If pore water is present, this results in localized dissolution at the grain contact. This results in irregular, sutured contacts between the grains. Stylolites in more cemented rocks, pressure solution takes place along much more extensive surfaces - these are stylolites . Dissolution often starts along a bedding surface, due to overburden pressure. A burial depth of at least several tens of metres is required for stylolite formation.