Metamorphic rocks

In nature, there are several varieties of rocks: sedimentary, metamorphic and magmatic. They are all compounds of certain minerals.

In this article, we will consider in detail what metamorphic rocks are. Let us describe their types, characteristics and methods of use in industry.

However, first of all, it is necessary to tell what rock is. This term is used to refer to chemical natural compounds that are formed in the earth's crust.

Metamorphic rocks arise inThe result of exposure to high temperatures and strong pressure on fossil magmatic or sedimentary origin. However, the chemical composition of minerals does not undergo significant changes, but they acquire a new texture and structure.

Many metamorphic fossils differshale (the presence of thin strips). This characteristic indicates the way the mineral is formed (under pressure). Such fossils have the ability to break into thin plates.

If the process of converting one of the minerals intoother (metamorphism) occurs under the influence of heat intrusive masses at a shallow depth, in which case the metamorphic rocks will have a corneal structure. An example of this is hornfels (biotite, pyroxene, amphibolite), formed from clay.

The process of metamorphism (modification) cansubject to any fossil - magmatic, sedimentary or metamorphic origin. Any transformations in rocks are carried out by means of their recrystallization in the solid state. And the degree of transformation of the original minerals can be very diverse, from small modifications up to significant rearrangements in the composition and shape of the fossil. The nature of metamorphism is also different. There can be only a small compaction, and maybe complete recrystallization of the mineral.

All metamorphic rocks are inherently a secondary product. Depending on the degree of transformation, several types of transition minerals are distinguished:

• Contact. Occur as a result of intrusion of magma (introduction into the thickness of the earth's crust) and its interaction with sedimentary rocks. Minerals of this kind are formed under the influence of pressure and high temperature. Such fossils include marble, skarn, migmatite. The rocks of contact metamorphism have a predominantly crystalline, massive, saccharose and weakly layered structure, while the composition of minerals undergoes significant changes.
• Regional (deep). The process of modification takes place at great depths under the interaction of high pressure, temperature and fluids. Mineralogical composition of minerals in this case does not always change. The rocks differ in crystalline, slate, dense structure.
• Dynamo-metamorphism. The transformation process occurs in tectonic plates under the action of high pressure. This type of minerals forms strong zones of crumpling and complex folds. Such minerals include the milonites and ka-takalazites.

Usually, metamorphic rocks occur innature in the form of veins, layers and lenses. They often retain the form of occurrence of the original mineral, but when they come into contact with magma intrusions, minerals can be irregular in shape.

Metamorphic minerals are used throughoutworld as a decorative, building and ornamental material (quartzite, marble, slates, gneiss). They are also used as industrial raw materials (asbestos, talc, etc.). In nature, metamorphic rocks are most often located near deposits of minerals, precious and ornamental stones (ruby, emerald, jadeite, garnet, etc.).