Definition of metasomatism in English:



  • [mass noun] Change in the composition of a rock as a result of the introduction or removal of chemical constituents.

    • ‘In the cooler middle and upper crust, felsic magmatism and aqueous metasomatism are most important.’
    • ‘In many cases, quartz overgrowths were preferentially corroded and dissolved in the presence of pyrophyllite, most likely during acidic metasomatism.’
    • ‘Much more commonly, however, metasomatism involves chemical exchange with fluids; in the earth's crust these fluids are usually aqueous solutions.’
    • ‘Textural relationships and geological context need to be determined to distinguish these burial-related phases from monazites ascribed to granite metasomatism or low-grade metamorphism.’
    • ‘Many experiments suggest that ancient subduction-related metasomatism affected OIB mantle sources long before island magmatism.’


Late 19th century: from meta- (expressing change) + Greek sōma, somat- body + -ism.