What minerals are in Migmatite?
(1) Petrologic Property
| Type | Subtype | Mineral composition |
|---|---|---|
| Regional metamorphic rock | Plagioclase leptite | Biotite (amphibolite), plagioclase, quartz, epidote |
| Plagioclase gneiss | Plagioclase, quartz, biotite | |
| Amphibolite (plagioclase amphibolite) | Andesine, hornblende | |
| Migmatite | Quartz, feldspar, less biotite |
What is the composition of a metamorphic rock?
General terms used to describe the chemical composition of both the protolith and the resulting metamorphic rock are: Pelitic Alumina rich rocks, usually shales or mudstones. Minerals like biotite, hornblende and plagioclase form during metamorphism and commonly produce amphibolites.
What is the parent rock of Migmatite?
Migmatite is a composite rock found in medium and high-grade metamorphic environments. If present, a mesosome, intermediate in color between a leucosome and melanosome, forms a more or less unmodified remnant of the metamorphic parent rock paleosome.
What is the composition of gneiss rock?
Gneiss is a medium- to coarse-grained, semischistose metamorphic rock. It is characterized by alternating light and dark bands differing in mineral composition (coarser grained than schist). The lighter bands contain mostly quartz and feldspar, the darker often contain biotite, hornblende, garnet or graphite.
What is migmatite composed of?
migmatite, in geology, rock composed of a metamorphic (altered) host material that is streaked or veined with granite rock; the name means “mixed rock.” Such rocks are usually gneissic (banded) and felsic rather than mafic in composition; they may occur on a regional scale in areas of high-grade metamorphism.
What is a migmatite in geology?
Migmatites are heterogeneous, medium- to high-grade metamorphic rocks with at least one component formed by partial melting. As migmatites form under P–T conditions common in the middle and lower crust, they are widespread and likely to be encountered in the field.
What is the texture and composition of metamorphic rocks?
html. TEXTURES Textures of metamorphic rocks fall into two broad groups, FOLIATED and NON-FOLIATED….
| Metamorphic Rocks | NOT BANDED |
|---|---|
| APHANITIC | |
| Fine-grained, PHYLLITIC texture, surfaces have satiny sheen, with crenulations (small wrinkles) | |
| ROCK NAME | PHYLLITE |
| PROTOLITH (Original Rock) | Shale Siltstone |
When rocks are metamorphosed the mineral components of the rock are?
Metamorphic rocks started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineral-rich fluids or, more commonly, some combination of these factors.
What is the texture of migmatite?
Migmatite – a high grade Barrovian metamorphic rock that has begin to fractionally melt. In appearance it looks like a gneiss intermixed with patches and splotches of phaneritic (coarse grained) igneous texture.
What type of rock is calcite?
Calcite is one of the most ubiquitous minerals, being an important rock forming mineral in sedimentary environments. It is an essential component of limestones, and occurs in other sedimentary rocks. It also occurs in metamorphic and igneous rocks, and is common in hydrothermal environments.
Why do gneisses shine?
Granite Gneiss/Schist. Gneiss is a metamorphic rock formed by changing schist, granite, or volcanic rocks through intense heat and pressure. Gneiss is foliated, which means that it has layers of lighter and darker minerals. Schists often have a high luster (they are very shiny) due to large crystals within the rock.
Why is Migmatite only half metamorphic rock?
Many migmatites probably represent the partial fusion of the metamorphic host during extreme metamorphism; the components of the rock with the lower melting temperatures are fused and gather to produce the streaks of granite. The migmatites of some Precambrian metamorphic terrains may be the result of this process.
What kind of rock is a migmatite made of?
Migmatite. The migmatites of some Precambrian metamorphic terrains may be the result of this process. Migmatite also can form near large intrusions of granite when some of the magma is injected into the neighbouring metamorphic rocks.
What kind of environment does migmatite come from?
Migmatite is a composite rock found in medium and high-grade metamorphic environments.
Why are migmatites found in Precambrian sedimentary rocks?
The migmatites of some Precambrian metamorphic terrains may be the result of this process. Migmatite also can form near large intrusions of granite when some of the magma is injected into the neighbouring metamorphic rocks.
Which is an example of a migmatite texture?
Schlieren textures are a particularly common example of granite formation in migmatites, and are often seen in restite xenoliths and around the margins of S-type granites.