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A rock of both metamorphic and igneous origin that exhibits characteristics of both rock types and probably forms through the heating but not melting of rocks in the presence of abundant fluids.

[Greek migma, migmat-, mixture (from mignunai, to mix; see meik- in Indo-European roots) + -ite.]


(Geological Science) a composite rock body containing two types of rock (esp igneous and metamorphic rock) that have interacted with each other but are nevertheless still distinguishable
[C20: alteration of Swedish migmatit, from Greek migma mixture + -ite1]
References in periodicals archive ?
The lithology types include gneisses of the 'Paraiba do Sul Complex'; migmatites and granites from the 'Rio Negro Complex', 'Suite Serra dos Orgaos' and 'Suite Rio de Janeiro'; intrusive bodies of the 'Rio Bonito Alkaline Complex' (syenite and nephelinesyenite); and Quaternary sediments (continental and transitional to marine/coastal), represented by marsh sediments, marine sediments, coastal sediments and alluvial sediments (Silva and Cunha 2001).
Until then, however, she surrendered to this irresistible attraction or, one might say, passion even, which was otherwise so utterly lacking in her own life that if she had let this awareness take control over her, her body would no doubt have instantly grown into the vulcanite wall paved with dark violet amethyst crystals, or into the metamorphic minerals, serpentinites, migmatites, and pegmatites, which are the occurrence of emeralds, diamonds, chrysoberyls, brazilianites, aquamarines, agates, and other gemstones across the country.
The dominant rock types in the area include low grade metamorphic rock such as chlorite schist, schistose quartzite, and quartz mica schist along with high grade migmatites and gneisses.
2007) estimated the Zr/Hf ratios of zircons from migmatites and augen orthogneisses of the Spanish Central System and suggested a slightly higher range (Zr/Hf = 36-56) for pure crustal signatures.
In this area we deal only with characteristic petrographic varieties of these two formations: conglomerates, sandstones, gneiss boulders, migmatites and light gray granites (Teisseyre, 1951; Teisseyre and Gawronski, 1965; Porqbski, 1981; Marcinowski et al.
28%), represented by various gneisses, migmatites, quartzites and meta-limestones, associated with plutonic and meta-plutonic rocks, composed predominantly of granite (IPECE, 2010).
In the Saghand region, the Chaydouni--Posht Badam complex rocks (Amphibolites, Gneisses, Schists, Migmatites, Anatectites) are indicative of a tectonic melange of Precambrian metamorphic rocks that have been transformed into Serpentinite together with Pyroxenite and pyroxene--olivine-bearing rocks [3].
The oldest rock unit is represented by Firan--solaf gneiss rocks which composed of coarse medium grained banded hornblende gneiss intercalated by migmatites and crossed by dykes metagabbroic rocks contain coarse to medium gruined metagabbric, which variably deformed and locally banded Diorite rocks crop out sporad cally over the area (EL-Masry et al.
Prominent rock units include granite gneiss, migmatites, schist/ quartz schist, porphyritic granite, fine-medium grained granite and charnockite.