Lexikon

in the geological terminology metamorphism means solid state changes in sedimentary, igneous and even metamorphic rocks. It takes place within the crust and in response to the agents of metamorphism: heat, pressure, chemically active fluids. The types of metamorphism are: 1. dynamic metamorphism that occurs along faults zones in response to pressure; 2. contact metamorphism resulting alteration of rocks at or near the contact of a cooling pluton; regional metamorphism occuring over a very large area in response to increased temperature and pressure.