What type of rock is Granulite?

To the German petrologists granulite means a more or less banded fine-grained metamorphic rock, consisting mainly of quartz and feldspar in very small irregular crystals and usually also containing a fair number of minute, rounded, pale-red garnets.

Is granulite metamorphic?

granulite facies, one of the major divisions of the mineral facies classification of metamorphic rocks, the rocks of which formed under the most intense temperature-pressure conditions usually found in regional metamorphism.

Is granulite a igneous rock?

Granulite (rock) – a high grade rock rich in pyroxene derived from the metamorphism of a mafic igneous parent rock.

What minerals are in granulite?

Trappgranulite: Obsolete term for mafic granulites (“pyroxene granulites”) mostly of basaltic composition and consisting of plagioclase, quartz, pyroxene (originally described as a micaceous mineral), pyrrhotine and garnet.

Is amphibolite an igneous rock?

Amphibolite: Some amphibolites are greenish, as determined by the color of the amphibole minerals. This specimen is actually an igneous rock. Some geologists call an igneous rock composed primarily of amphibole minerals an amphibolite or “hornblendite.” USGS image.

What is charnockite rock?

charnockite, any member of a series of metamorphic rocks with variable chemical composition, first described from the state of Tamil Nadu in southern India and named for Job Charnock. The term is often limited to the characteristic orthopyroxene granite of the series.

What kind of rock can be a protolith?

Protoliths are usually granites, rhyolites, or arkose sandstones and metamorphism results in gneisses containing an abundance of quartz, feldspar, and biotite.

Is Basalt a protolith?

Basalt is the most common mafic protolith. It can turn into mafic metamorphic rocks such as greenschist and amphibolites with chlorite, actinolite, biotite, hornblende, or plagioclase in them, depending on metamorphic grade.

Is gneiss a protolith?

The protolith of gneiss may be an igneous rock, in this case it is called an orthogneiss. It forms probably because of shear in vicous granitic magma. Paragneiss is a variety with a sedimentary protolith.

Which is the parent rock?

Parent rock can be sedimentary, igneous or metamorphic. In the context of metamorphic rocks, the parent rock (or protolith) is the original rock before metamorphism occurred.

What rocks form metamorphic rocks?

The word metamorphism is taken from the Greek for “change of form”; metamorphic rocks are derived from igneous or sedimentary rocks that have altered their form (recrystallized) as a result of changes in their physical environment.

Which rock is called primary rock?

Primary rock is an early term in geology that refers to crystalline rock formed first in geologic time, containing no organic remains, such as granite, gneiss and schist as well as igneous and magmatic formations from all ages.

What is regional metamorphic rock?

In regional metamorphism, rocks that form closer to the margin of the tectonic plates, where the heat and pressure are greatest, often differ in their minerals and texture from those that form farther away. Compare contact metamorphism.

What is regional rock?

Regional metamorphic rocks occur where rocks are altered by high temperatures and / or high pressures usually deep within the Earth. Regional metamorphism can affect large volumes of the crust and typically happens at convergent plate boundaries, beneath new mountain ranges.

Which rock is formed by regional metamorphism?

Regional metamorphism usually produces foliated rocks such as gneiss and schist.

What is an example of regional metamorphism rock?

Regionally metamorphosed rocks usually have a squashed, or foliated appearance – examples include slate, schist and gneiss (pronounced “nice”), formed by metamorphism of mudstones, and also marble which is formed by metamorphism of limestone.

What are the 5 types of regional metamorphism?

According to the composition type, metamorphic rock can be also divided into five series: (1) mudstone series (slate, phyllite, mica schist, biotite gneiss), (2) felsic series (quartzite, plagioclase gneiss, leptynite, and leucoleptite), (3) carbonate rock series (calcium and magnesium metamorphic rock series, such as …

Is igneous rock metamorphic?

If there is too much heat or pressure, the rock will melt and become magma. This will result in the formation of an igneous rock, not a metamorphic rock.

How do you identify regional metamorphism?

Regional metamorphism occurs when rocks are buried deep in the crust. This is commonly associated with convergent plate boundaries and the formation of mountain ranges. Because burial to 10 km to 20 km is required, the areas affected tend to be large. Most regional metamorphism takes place within continental crust.

How are metamorphic rocks classified?

Metamorphic rocks are broadly classified as foliated or non-foliated. Non-foliated metamorphic rocks do not have aligned mineral crystals. Non-foliated rocks form when pressure is uniform, or near the surface where pressure is very low.

How does metamorphic rock change into another type of metamorphic rock?

Metamorphic rocks are formed by tremendous heat, great pressure, and chemical reactions. To change it into another type of metamorphic rock you have to reheat it and bury it deeper again beneath the Earth’s surface.

What is pelitic rock in geology?

A pelite (Greek: pelos, “clay”) or metapelite is a metamorphosed fine-grained sedimentary rock, i.e. mudstone or siltstone.

What is Arenite rock?

arenite, any sedimentary rock that consists of sand-sized particles (0.06–2 millimetres [0.0024–0.08 inch] in diameter), irrespective of composition. More formal nomenclature of such rocks is based on composition, particle size, and mode of origin—e.g., sandstone, quartzite, lithic arenite, and feldspathic arenite.

Is shale a pelitic?

Metamorphic rocks

Disten or sillimanite, cordierite, and staurolite schists occur in conditions of high-degree metamorphism from pelite sediment, that is, shale, mudstone, and marl.

How do you identify sillimanite?

Sillimanite is a metamorphic mineral found in high grade aluminous schists and gneisses. It is a polymorph of andalusite and kyanite, all having formula Al₂SiO₅. Keys to identification are high relief, needle-like, fibrous or bladed habit, characteristic square cross sections with one diagonal cleavage.

Is sillimanite a rock or a mineral?

Sillimanite is one of three aluminosilicate polymorphs, the other two being andalusite and kyanite. A common variety of sillimanite is known as fibrolite, so named because the mineral appears like a bunch of fibres twisted together when viewed in thin section or even by the naked eye.

What rock is sillimanite found in?

Introduction: sillimanite is a metamorphic mineral found in high-grade rocks (upper amphibolite/lower granulite facies) most typically in aluminium-rich pelites. Sillimanite has two polymorphs, kyanite and andalusite, which develop under conditions of lower temperature and different pressure to sillimanite.