The process by which a rock's overall chemical composition changes during metamorphism because of reactions with hot water that bring in or remove elements.
selected addition and removal of chemical elements by hot, briny fluids, which soak rocks during metamorphism. Often, the "parent" rock changes to resemble granite, even though it never was igneous.
the process by which the chemical constitution of a rock is changed by the action of fluids. [AHDOS
Metasomatism is the chemical alteration of a rock by hydrothermal and other fluids. It is also known as "alteration".