Origin of granite

There are two theories for the origin of granite. The magmatic theory states that granite is derived by the crystal fractionation of magma. Thus granite bodies are the result of intrusion of liquid magma into the existing rocks. The granitization theory states that granite is formed in place by extreme metamorphism. There is evidence to support both theories, and both are useful to explain different observed features. The two may actually merge: as metamorphic conditions increase to the melting point of the metamorphosed granite, it will melt and become a liquid magma.