What is meant by mantle metasomatism?

Mantle metasomatism is a relatively recent concept introduced in the early 1970s when detailed studies of lithospheric mantle rock fragments (xenoliths), brought to the surface of in basaltic to kimberlitic magmas, became widespread.

What are the types of metasomatism?

Two main types of metasomatism are differentiated affecting mainly the harzburgites: a silicate-melt metasomatism of Fe–Ti type and a carbonatite metasomatism. Both types are recognized in the nearby Pyrenean peridotite massifs, but the presence of hydrous minerals is less frequent in the xenoliths.

What is metasomatism in geology?

Metasomatism refers to the process whereby a preexisting igneous, sedimentary, or metamorphic rock undergoes compositional and mineralogical transformations associated with chemical reactions triggered by the reaction of fluids (so-called metasomatic agents), which invade the protolith.

What is a contact metasomatism?

The term contact metasomatism, generally attributed in the first instance to Barrell (1907), refers to a process of chemical change in the composition of rocks adjacent to igneous intrusions, the change being brought about by migration of elements originating from the magma or the host.

What is the difference between metamorphism and metasomatism?

If metamorphism is defined as the process by which a mineral assemblage reequilibrates in response to changes in pressure and temperature (P, T), then metasomatism is the reequilibration of a rock involving a change in the chemical composition.

Which style of metamorphism is associated with Metasomatism?

allochemical metamorphism
This process of significant chemical change during metamorphism is known as ‘allochemical metamorphism’ or ‘metasomatism’, and rocks formed in this manner are metasomatic rocks.

What is the mechanism of metasomatism?

Metasomatism is first of all the result of interaction between the solid porous body of rock and the intra-pore fluids. Its essential consequence, and the criterion setting it apart from metamorphism, is the total change in the chemical composition of the body, within the volume affected by metasomatism (5).

What fluid is generally responsible for metasomatism?

Most metamorphic fluids must be rich in silica and alkalis, which may result in the appearance of aggressive silica-alkali fluids responsible for regional metasomatism and granitization. In general, the solubility of Fe-, Mg-, Mn-, and Ca-bearing minerals in alkaline solutions is low compared with acidic solutions.

What is the main cause of metasomatism?

In the metamorphic environment, metasomatism is created by mass transfer from a volume of metamorphic rock at higher stress and temperature into a zone with lower stress and temperature, with metamorphic hydrothermal solutions acting as a solvent.

Is metasomatism a type of metamorphism?

metamorphic process process is referred to as metasomatism. If a granite is emplaced into a limestone, the contact region may be flooded with silica and other components, leading to the formation of a metasomatic rock.

Is metasomatism a closed system?

Metamorphic mineral growth usually requires the movement of atoms, from a phase that is breaking down into one that is growing. So on the scale of a mineral grain we are not dealing with a closed system at all.

What is metasomatism and how this differentiates from metamorphism?