What is Pneumatolytic phase?

What is Pneumatolytic phase?

Pneumatolysis is an obsolete geologic term for magma emitting gasses that alter surrounding rock or crystallize minerals. Pneumatolysis is now considered a type of hydrothermal interaction.

What is pneumatolytic metamorphism?

Contact metamorphism in which the composition of a rock has been altered by introduced gaseous magmatic material.

What is hydrothermal metamorphism?

In metamorphic rock: Hydrothermal metamorphism. Changes that occur in rocks near the surface where there is intense activity of hot water are categorized as hydrothermal metamorphism.

What is Tourmalinisation?

Tourmalinisation is the metasomatic replacement of feldspars and micas by the mineral tourmaline. The reaction is complex but involves the circulation of hydrothermal fluids rich in both the elements boron and fluorine. Tourmaline (dark) + quartz (white).

What is lime Metasomatism?

1 Lime metasomatism is illustrated by the formation of epidote at the expense of micas, and iron metasomatism by many processes through which basic igneous rocks, slates, and limestones have been replaced by ferriferous solutionl to form iron ores.

What happens when shale is metamorphosed?

Shales that are subject to heat and pressure of metamorphism alter into a hard, fissile, metamorphic rock known as slate. With continued increase in metamorphic grade the sequence is phyllite, then schist and finally gneiss.

What causes 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.

How does metasomatism process occur?

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.