Metamorphism's the solid-state recrystallization of pre-existing rocks due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids. Both mineralogical, chemical and crystallographic changes can occur during this process. Three types of metamorphism exist: dynamic, contact and regional. Metamorphism produced with increasing pressure and temperature conditions's known as prograde metamorphism. Conversely, decreasing temperatures a… (More on Metamorphism)