@prefix qx8: . @prefix skos: . qx8:-N5RTB4ND-P skos:prefLabel "quartzite"@fr, "quartzite"@en ; a skos:Concept ; skos:broader qx8:-13M320QW-Q . qx8:-TCTMWRN4-H skos:prefLabel "gneiss"@fr, "gneiss"@en ; a skos:Concept ; skos:broader qx8:-13M320QW-Q . qx8:-13M320QW-Q a skos:Concept ; skos:inScheme qx8: ; skos:definition "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. During this process, the rock remains mostly in the solid state, but gradually recrystallizes to a new texture or mineral composition. The protolith may be an igneous, sedimentary, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by their protolith, their chemical and mineral makeup, and their texture. They may be formed simply by being deeply buried beneath the Earth's surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction, and distortion. Metamorphic rock can be formed locally when rock is heated by the intrusion of hot molten rock called magma from the Earth's interior. The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides information about the temperatures and pressures that occur at great depths within the Earth's crust. (Adapted from: https://en.wikipedia.org/wiki/Metamorphic_rock)"@en, "Une roche métamorphique est un type de roches dont la formation a pour origine la transformation à l'état solide des roches sédimentaires, magmatiques ou encore métamorphiques dans un régime de contraintes au cours d'un temps long, en raison des modifications des paramètres physico-chimiques du milieu dans lequel elles évoluent (notamment la pression, la température et la teneur en eau). Cette transformation, désignée sous le terme de métamorphisme, se traduit par une modification de la texture, de l'assemblage minéralogique à l'équilibre ou de la composition chimique de la roche. La roche originelle d'une roche métamorphique est appelée le protolithe. En raison de leur diversité et de la complexité pour déterminer leur origine, la classification des roches métamorphiques n'est pas clairement définie et se base sur différents critères qui amènent à plusieurs types de classification. (Adapté de : https://fr.wikipedia.org/wiki/Roche_m%C3%A9tamorphique)"@fr ; skos:narrower qx8:-7QZ96S23-2, qx8:-N5RTB4ND-P, qx8:-TCTMWRN4-H, qx8:-KS4DWKXJ-J ; skos:prefLabel "roche métamorphique"@fr, "metamorphic rock"@en ; skos:exactMatch , , ; skos:broader qx8:-KFDBL3TR-S . qx8: a skos:ConceptScheme . qx8:-7QZ96S23-2 skos:prefLabel "amphibolite"@fr, "amphibolite"@en ; a skos:Concept ; skos:broader qx8:-13M320QW-Q . qx8:-KFDBL3TR-S skos:prefLabel "roche"@fr, "rock"@en ; a skos:Concept ; skos:narrower qx8:-13M320QW-Q . qx8:-KS4DWKXJ-J skos:prefLabel "greenstone"@en, "roche verte"@fr ; a skos:Concept ; skos:broader qx8:-13M320QW-Q .