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Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith ) is subjected to temperatures greater than 150 to 200 °C (300 to 400 °F) and, often, elevated pressure of 100 megapascals (1,000 bar ) or more, causing profound physical or chemical changes.
In practice, garnet is commonly used in the study of metamorphic rocks due to its refractory nature. [22] In past studies, garnet is found to be a mineral that is stable under a wide range of P-T conditions, meanwhile chemically displays responses (e.g. ions exchange ) to the P-T variations throughout its metamorphic history without reaching ...
Granulite – Class of high-grade medium to coarse grained metamorphic rocks; Greenschist – Metamorphic rock – A mafic metamorphic rock dominated by green amphiboles; Hornfels – Group of metamorphic rocks Calcflinta – Calc-silicate hornfels; Jadeitite – Metamorphic rock found in blueschist-grade metamorphic terranes
In metamorphic geology, a compatibility diagram shows how the mineral assemblage of a metamorphic rock in thermodynamic equilibrium varies with composition at a fixed temperature and pressure. Compatibility diagrams provide an excellent way to analyze how variations in the rock's composition affect the mineral paragenesis that develops in a ...
Soapstone (also known as steatite or soaprock) is a talc-schist, which is a type of metamorphic rock. It is composed largely of the magnesium -rich mineral talc . It is produced by dynamothermal metamorphism and metasomatism , which occur in subduction zones , changing rocks by heat and pressure, with influx of fluids but without melting.
The platiness gives the rock schistosity (a tendency to split into layers). Other common minerals include quartz, orthoclase, talc, carbonate minerals and amphibole . [1] Greenschist is a general field petrologic term for metamorphic or altered mafic volcanic rock. In Europe, the term prasinite is sometimes used.
Impactite is rock created or modified by one or more impacts of a meteorite. [1] [2] Impactites are considered metamorphic rock, because their source materials were modified by the heat and pressure of the impact. [3] On Earth, impactites consist primarily of modified terrestrial material, sometimes with pieces of the original meteorite. [3]
The metamorphic facies is not usually considered when classifying metamorphic rock based on protolith, mineral mode, or texture. However, a few metamorphic facies produce rock of such distinctive character that the facies name is used for the rock when more precise classification is not possible. The chief examples are amphibolite and eclogite.