Our planet is an integrated dynamic system. Its components are divided into shells - geospheres. The most voluminous of them is the mantle. Other planets have a similar shell, but we will talk about the earth.
What is a mantle?
The mantle is part of the Earth’s hard shell. It is conditionally divided into upper and lower parts, located between the earth's crust and the very center of the planet - the core. Its lower boundary runs at a distance of 2900 kilometers from the Earth's surface, the upper - at a distance of approximately 30 kilometers.
The mantle is the largest geosphere of the planet both in mass and in volume. It is about 80% of the globe, and its mass is 67% of the mass of the planet. At a depth of 670 kilometers, its lower and upper layers are separated by the Golitsyn line. It is named after the famous Russian physicist.
The crust and mantle are separated by the Moho line. Under the folded areas, it is much further from the surface, lying at a depth of about 70 kilometers, and under the oceans it rises much higher, located at a depth of about 7 kilometers. In this area, a sudden increase in the speed of seismic waves is observed.
Composition and structure
Despite all the information available, the mantle is one of the little-studied areas. Its location does not provide opportunities for large-scale research. Scientists obtain some of the information about it thanks to the movement of deep rocks to the surface of the Earth, but the exact geological composition of the shell remains a mystery.
With a high probability, it is known that the mantle is formed to a greater extent by refractory rocks, in contrast to the low-melting earth crust. The main rocks of the mantle are peritotites, eclogites, and perovskites. Mantle melts carry diamonds, xenoliths, alkaline basalts and kimberlites to the surface.
Many mantle rocks are not found at all in the earth's crust, for example, phlogopite peridotites or carbonatites. The shell contains a high concentration of oxygen, silicon, magnesium, aluminum, iron and their oxides.
Processes in the mantle
It is assumed that the temperature inside it reaches 2500 degrees Celsius, which means it must be liquid. However, high pressure increases the melting point of substances, so the mantle is a hard shell.
Due to the strong pressure in the earth's crust, cracks begin to form. When the pressure weakens, the rocks heat to such an extent that they begin to melt, forming magma. It moves up the splits and goes outside in the form of lava of volcanoes.
The activity of the mantle forms the relief of the planet. And in places where magmatic rocks are raised, large mineral deposits are formed.