Migmatite

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migmatite

[′mig·mə‚tīt]
(petrology)
A mixed rock exhibiting crystalline textures in which a truly metamorphic component is streaked and mixed with obviously once-molten material of a more or less granitic character.

Migmatite

 

a rock consisting of metamorphic enclosing material with veins of granite. It is formed when liquid strata of granitic magma penetrate along the cleavage of metamorphic rocks. The granitic magma may form through the partial melting (anatexis) of metamorphic rocks under conditions of deep burial (regional metamorphism), when the molten rock is forced out of the unmelted metamorphic remainder. Many Precambrian migmatites were formed under such conditions. Migmatites located near large intrusive bodies of granitoids arose when granitic melt was injected into adjacent metamorphic rocks (injection gneiss). Migmatite is commonly found in ancient granite-gneiss complexes.

References in periodicals archive ?
The Laguigangri Group crops out in the core of the Yelaxiangbo dome and is composed of schist, gneiss, and migmatite units (Figure 1(b)).
Prominent rock units include granite gneiss, migmatites, schist/ quartz schist, porphyritic granite, fine-medium grained granite and charnockite.
The Bedonia Project is underlain by rocks of the Proterozoic Mount Andrews Migmatites and contains a number of magnetic features (ten current targets) that may be related to intrusive mafic rocks (the host rocks for the Nova nickelcopper discovery).
Carbon content (kg m-2, 0-30cm depth) in dominant soil units in PNM C (kg m-2) Umbric Leptosols of granites 18.2 Umbric Cambisols of schists 17 Umbric Cambisols of granites 7.6 Umbric Leptosols of basic rocks 6.9 Umbric Leptosols of schists 5.0 Chromi Luvisols of basic rocks 4.6 Dystric Fluvisols of alluvium 4.6 Dystric Leptosols of migmatites 2.6 Dystric Cambisols of migmatites 2.5 Eutric Leptosols of ulti amafie rocks 2.2 Haplic Alisols of sedimentary deposits 2.2 Eutric Leptosols of ultramafic rocks 2.2 Dystric Cambisols of sedimentary.
Within the Garzon Massif the plutonic bodies intrude Precambrian high grade metamorphic rocks whereas in the Upper Magdalena Valley, plutonic rocks intrude migmatites of unknown age (Alvarez, 1981; Kroonemberg, 1982; Alvarez and Linares, 1983; Velandia et al, 2001a, 2001b; Jimenez et al., 2006).
the GAC publication The Dynamics of Epeiric Seas, and the Atlas of Migmatites published by MAC), textbooks (e.g.
(2004), these soils were developed both from Devonian sedimentary rocks (Ponta Grossa Formation) and from Precambrian rocks such as subalcaline granites, syenites, and migmatites. The terrain is gently sloping to undulating, with slopes mostly <6%.
This atlas of migmatites, heterogeneous rocks often found in continental crusts, is designed for geologists and mineralogists who need a reference for identifying and classifying these substances in the field.
The Vijayan Complex rocks consists of mainly granitic gneisses, hornblende biotlite gneisses, and migmatites formed under amphibolites facies, and are mainly confined to the eastern sector.
The latter often contains migmatites or small bodies of enderbitic composition, otherwise plagioclase-potassium-feldspar leucosomes and granites prevail.