The word "posttectonic" refers to geological periods and processes that occur after the major tectonic movements have taken place. Some synonyms for this word include "post-orogenic," "post-metamorphic," and "post-volcanic." These terms describe the stages that occur in the geological history of the earth, which can span millions of years. Post-orogenic refers to the time after mountains have formed, when the earth's surface has stabilized and erosion processes begin to modify the landscape. Post-metamorphic refers to rocks that have undergone significant alteration due to heat and pressure, but are now stable and have ceased to change. Post-volcanic refers to rocks formed after a volcanic eruption and the subsequent cooling of magma.