Editing Metamorphism (section)

===Plastic deformation===
In plastic deformation pressure is applied to the [[protolith]], which causes it to shear or bend, but not break. In order for this to happen temperatures must be high enough that brittle fractures do not occur, but not so high that diffusion of crystals takes place.{{sfn|Vernon|1976|p=149}}
As with pressure solution, the early stages of plastic deformation begin during diagenesis.{{sfn|Boggs|2006|pp=147–154}}