The process by which the chemical composition of a rock is changed by interaction with fluids; replacement of one mineral by another without melting.
The metamorphic process by which minerals of a rock or ore body are replaced by minerals of a different chemical composition as a result of the action of a fluid, esp. of moving water.
The process by which the chemical composition of a rock is changed through the introduction or extraction of chemicals dissolved in fluids that migrate through the rock's pores. Metasomatism often results in the formation of new minerals, especially metal ore deposits.