Metamorphism
change of minerals in rocks without melting into magma, occurring due to heat, pressure, and chemically active fluids
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism usually takes place at temperatures in excess of 150 °C (300 °F), and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface.
Various forms of metamorphism exist, including regional, contact, hydrothermal, shock, and dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as prograde metamorphism, while decreasing temperature and pressure characterize retrograde metamorphism.
Metamorphic petrology is the study of metamorphism. Metamorphic petrologists rely heavily on statistical mechanics and experimental petrology to understand metamorphic processes.
Metamorphic processes
Metamorphism is the set of processes by which existing rock is transformed physically or chemically at elevated temperature, without actually melting to any great degree. The importance of heating in the formation of metamorphic rock was first recognized by the pioneering Scottish naturalist, James Hutton, who is often described as the father of modern geology.
This brief starts where responsible research should: with the source description of “Metamorphism” as change of minerals in rocks without melting into magma, occurring due to heat, pressure, and chemically active fluids. Everything that follows is an evidence route, not borrowed authority.
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The subject matters to the general reference register because the source frames it as change of minerals in rocks without melting into magma, occurring due to heat, pressure, and chemically active fluids. Its deeper value depends on whether names, dates, institutions and citations support that framing.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 16, 2026. The linked authority identifier is Q380971. The Library of Congress control number is sh85084270. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank.
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This entry incorporates text from “Metamorphism” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.