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 as a result of exposure to high temperatures and strong pressure on fossils of 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 are distinguished by shale (the presence of thin stripes). 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 transformation of some minerals into others (metamorphism) occurs under the influence of heat intrusive masses at a shallow depth, in this case metamorphic rocks will have a corneal structure. An example of this is hornfels (biotite, pyroxene, amphibolite), formed from clay.

The process of metamorphism (modification) can be subjected to any fossils - magmatic, sedimentary or metamorphic origin. Any transformations in rocks are carried out by means of their recrystallization in the solid state. Moreover, the degree of transformation of the initial minerals can be very diverse, from small Modifications Up to significant rearrangements in the composition and appearance 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 (penetration into 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 are predominantly crystalline, massive, saccharose and weakly layered, 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, shale, 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 fossil include the milonites and ka-takalazites.

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

Metamorphic minerals are used all over the world as 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.).