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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 ...
Migmatite is a gneiss consisting of two or more distinct rock types, one of which has the appearance of an ordinary gneiss (the mesosome), and another of which has the appearance of an intrusive rock such pegmatite, aplite, or granite (the leucosome). The rock may also contain a melanosome of mafic rock complementary to the leucosome. [11]
This page is intended to be a list of rock textural and morphological terms ... see also schlieren and migmatite; E ... Wikipedia® is a registered ...
The Migmatite-Gneiss Complex covers half of Nigeria's surface area and encompasses Archean gray gneisses, with tonalite and granodiorite consistencies. Within this complex are occurrences of schist , migmatite , garnet , sillimanite , kyanite and staurolite , which together indicate high-grade metamorphism up to the level of amphibolite on the ...
The rock record contains an uncertain age gap with younger 1.8 billion years old Proterozoic quartzofeldspathic and migmatite gneiss, with amphibolite and biotite schist. Around 1.9 billion years ago, mafic, intermediate and felsic rocks, in some cases with subordinate metasedimentary rocks, began to form and metamorphosed, reaching greenschist ...
A migmatite consists of dark, refractory rock (the melanosome) that is permeated by sheets and channels of light granitic rock (the leucosome). The leucosome is interpreted as partial melt of a parent rock that has begun to separate from the remaining solid residue (the melanosome). [41]
The minerals present in a granulite will vary depending on the parent rock of the granulite and the temperature and pressure conditions experienced during metamorphism. A common type of granulite found in high-grade metamorphic rocks of the continents contains pyroxene , plagioclase feldspar and accessory garnet , oxides and possibly amphiboles .
Svecofennian migmatite rock outcrop on the island of Berghamn in the municipality of Pargas at the southwestern tip of Finland. The lighter parts of the outcrop are granite and the darker parts are mica schist.