hypermetamorphic

Hypermetamorphism is a term used in geology to describe metamorphic conditions that exceed the intensity of typical regional metamorphism. It is generally linked to very high temperatures and/or significant fluid activity, causing rapid and extensive mineralogical changes in rocks.

The usage of hypermetamorphism is not uniform across the literature. Some authors apply it to ultra-high-temperature or ultra-high-pressure metamorphism, while others use it to describe intense hydrothermal alteration or rapid, metasomatic replacement that accompanies high-grade metamorphism.

Mechanisms involve deep burial in tectonic settings, contact with hot intrusions, and/or abundant fluids that promote metamorphic reactions. The resulting rocks may show disequilibrium textures, new mineral assemblages, and advanced recrystallization that erase earlier fabric.

Hypermetamorphic processes are reported in several tectonometamorphic belts and in zones of intense hydrothermal activity. Because the term is variably defined, precise interpretations depend on the regional context and the specific mineral associations observed.

See also metamorphism, granulite facies metamorphism, ultra-high-temperature metamorphism, contact metamorphism, and hydrothermal metamorphism.