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Migmatite identification and geology

A composite rock found in high-grade metamorphic terranes that contains both metamorphic and igneous-looking components, formed when partial melting begins but does not go to completion. The lighter-colored, granite-like portions leucosomes represent the partial melt or melt-derived material, while the darker, more refractory portions melanosomes and mesosomes represent the residual metamorphic host. Migmatites mark the transition between metamorphism and igneous processes. Field: petrology. Example: Migmatites exposed along the coast of southwest Finland display intricate folded leucosomes within biotite-rich gneiss, recording the onset of partial melting during the Svecofennian orogeny approximately 1.9 billion years ago.. Related terms: Gneiss, Partial melting, Anatexis, Leucosome.

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Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:42.055955+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Migmatite mean in geology?
A composite rock found in high-grade metamorphic terranes that contains both metamorphic and igneous-looking components, formed when partial melting begins but does not go to completion. The lighter-colored, granite-like portions leucosomes represent the partial melt or melt-derived material, while the darker, more refractory portions melanosomes and mesosomes represent the residual metamorphic host. Migmatites mark the transition between metamorphism and igneous processes.
What is an example of Migmatite?
Migmatites exposed along the coast of southwest Finland display intricate folded leucosomes within biotite-rich gneiss, recording the onset of partial melting during the Svecofennian orogeny approximately 1.9 billion years ago.
Which earth-science field uses the term Migmatite?
Migmatite is used in petrology.
Which terms are related to Migmatite?
Related terms in this reference are Gneiss, Partial melting, Anatexis, Leucosome.

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