What type of rock is pelitic?

What type of rock is pelitic?

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

What minerals are in pelite?

As in the ALC, pelite in the Split Lake Block consists of well-layered quartz, feldspar, biotite, garnet, and sillimanite with trace sulfides ± graphite.

How is pelite formed?

pelite (adj. pelitic) An aluminium-rich, metamorphic rock formed by the metamorphism of clay-rich sedimentary rocks, e.g. shales and mudstones.

What is the protoliths of pelitic rock is?

Pelitic protoliths are mainly composed of clay minerals derived from weathered and eroded continental crust. With increasing metamorphic grade, they are transformed to slates, phyllites, mica-schists, and granulites. Carbonate rocks mainly originate from biogenic sediments. Pure carbonate sediments are SiO2-free.

What is pelitic gneiss?

Pelitic schists or pelitic gneisses are derived by metamorphism of argillaceous or fine-grained aluminous sediments. The pelitic protolith is generally very fine-grained. During metamorphic overprint there is only a slight coarsening of the mineral grains in the corresponding like-grained metamorphic product.

What does Schistosity mean in geology?

schistosity, mode of foliation that occurs in certain metamorphic rocks as a consequence of the parallel alignment of platy and lath-shaped mineral constituents. It reflects a considerable intensity of metamorphism—i.e., changes resulting from high temperatures, pressures, and deformation. Related Topics: foliation.

What is protolith marble?

A protolith is a parent rock in metamorphism; what the rock is before it undergoes metamorphism. Limestone is a protolith for marble.

Is gneiss a pelitic rock?

The gneisses are a very varied group, including both igneous rocks and metamorphosed sedimentary rocks , and may be categorized as quartzofeldspathic, pelitic, calcarous, or hornblende gneiss.

What kind of minerals are commonly found in gneiss?

Gneiss is a coarse to medium grained banded metamorphic rock formed from igneous or sedimentary rocks during regional metamorphism. Rich in feldspars and quartz, gneisses also contain mica minerals and aluminous or ferromagnesian silicates.

What is sillimanite mineral?

sillimanite, also called Fibrolite, brown, pale green, or white glassy silicate mineral that often occurs in long, slender, needlelike crystals frequently found in fibrous aggregates. An aluminum silicate, Al2OSiO4, it occurs in high-temperature regionally metamorphosed clay-rich rocks (e.g., schists and gneisses).

What mineral is sillimanite?

aluminosilicate mineral
Sillimanite is an aluminosilicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist Benjamin Silliman (1779–1864).

What minerals are in amphibole?

The amphiboles typically occur with plagioclase feldspar, quartz, and biotite, as well as with chlorite and oxide minerals. In magnesium-rich rocks, tremolite, anthophyllite, and hornblende may exist together. Gedrite and cummingtonite coexist with garnet in rocks enriched in aluminum and iron.

What is the mineral group of amphibole?

Amphiboles are a major group of hydrous minerals that occur in a wide range of rock types. They occur predominantly in metamorphic and igneous rocks of the Earth’s crust and upper mantle. Two metamorphic facies are defined by their characteristic amphiboles.

How does schistosity differ from cleavage?

Schistosity is when minerals that begin to grow in the rock form parallel lines. Disjunctive cleavage is when the cracks are somewhat parallel, with crossovers and zigzags and spaces of undeformed rock in between.

What rock shows schistosity?

Schist can form from many different kinds of rocks, including sedimentary rocks such as mudstones and igneous rocks such as tuffs. Schist metamorphosed from mudstone is particularly common and is often very rich in mica (a mica schist).

What is ACF diagram?

ACF diagram A three-component, triangular graph used to show how metamorphic mineral assemblages vary as a function of rock composition within one metamorphic facies.