A metamorphic process is a process that certain rocks undergo to change their chemical or structural composition. In rocks, a metamorphic process may be classified as either contact or regional depending on the scale and area of rock that undergoes a change.
A contact metamorphic process is a process that occurs in a relatively small and localized area. The rocks undergoing the process change their structure or chemical composition due to moderate pressure and heat that they come into contact with. Regional metamorphic processes occur in very large areas such as whole mountain ranges. This type of process occurs due to heat, pressure and the movement of tectonic plates.