migmatite
Sign in to savethumb|Ptygmatic folding in migmatite on Naissaar Island, Estonia thumb|Migmatite on the coast of Saaremaa, Estonia thumb|Intricately-folded migmatite from near Geirangerfjord, Norway
Article
12 sectionsContents
- The diagenesis - metamorphism sequence
- Partial melting, anatexis and the role of water
- Color-banded migmatites
- Migmatite textures
- Early history of migmatite investigations
- Agmatite
- Migmatite melts provide buoyancy for sedimentary isostasy
- Other migmatite hypotheses
- Etymology
- See also
- References
- External links
thumb|Ptygmatic folding in migmatite on Naissaar Island, Estonia thumb|Migmatite on the coast of Saaremaa, Estonia thumb|Intricately-folded migmatite from near Geirangerfjord, Norway
Migmatite is a composite rock found in medium and high-grade metamorphic environments, commonly within Precambrian cratonic blocks. It consists of two or more constituents often layered repetitively: one layer is an older metamorphic rock that was reconstituted subsequently by partial melting ("paleosome"), while the alternate layer has a pegmatitic, aplitic, granitic or generally plutonic appearance ("neosome"). Commonly, migmatites occur below deformed metamorphic rocks that represent the base of eroded mountain chains.