Encyclopedia of Advanced Igneous Petrology, Hydrothermal Geochemistry, and Volcanic Formations

• Autometamorphism — A geological process of mineralogical transformation and alteration of an igneous rock, caused in the final stages of its consolidation by its own residual gases, water vapor, and hydrothermal solutions released during magma cooling. This phenomenon transforms unstable primary minerals into new secondary assemblages (such as serpentinization or chloritization of basalts) without the input of external tectonic pressures or temperatures.