metasomatism
/ˌmɛtəˈsəʊmətɪz(ə)m
/noun [mass noun] Geology
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....
- 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.
- Much more commonly, however, metasomatism involves chemical exchange with fluids; in the earth's crust these fluids are usually aqueous solutions.
Derivatives
metasomatic
- Specifically, gangue formed by both metasomatic alteration and precipitation during ore formation can yield a wealth of information about the origins and physical conditions of the ore-forming fluids.
- Dolerite dykes that cut the peridotite show chilled margins and local metasomatic calcic alteration.
- Jadeite dykes are intruded within serpentinites and are the metasomatic products of crystallization from hydrous fluids reacting with the serpentinites.
metasomatize
- Most recent studies of potassic magma generation ascribe such characteristics to metasomatized portions of the subcontinental lithosphere.
- When metamorphism is accompanied by a change in the chemistry of a rock, the rock is said to have been metasomatized.
- These fluids altered and metasomatized the previously emplaced volcanic products (lavas, pyroclasts).
Origin
Late 19th century: from meta- (expressing change) + Greek sōma, somat- 'body' + -ism.