The structure of our planet is heterogeneous. One consists of several levels, including solid and liquid shells. What are the layers of the earth called? How many of them? How do they differ from each other? Let's figure it out.
How did the layers of the earth form?
Among the planets of the terrestrial group (Mars, Venus, Mercury), the Earth has the largest mass, diameter and density. It formed about 4.5 billion years ago. According to one version, our planet, like others, was formed from small particles that arose after the Big Bang.
Debris, dust and gas began to unite under the influence of gravity and took on a spherical shape. The proto-earth was very hot and melted minerals and metals falling on it. More dense substances went down to the center of the planet, less dense went up.
So the first layers of the Earth appeared - the core and the mantle. Together with them, a magnetic field arose. From above, the mantle gradually cooled and covered with a film, which later became a bark. The processes of planet formation did not end there, in principle, they continue today.
Gases and seething mantle materials constantly broke out through cleavages in the crust. Their weathering formed the primary atmosphere. Then, along with hydrogen and helium, there was a lot of carbon dioxide in it. Water, according to one version, appeared later from the condensation of ice, which was brought in by asteroids and comets.
Nucleus
The layers of the Earth are represented by the core, mantle and crust. All of them differ in their properties. In the center of the planet is the core. It has been studied less than other shells, and all information about it is, albeit scientific, but still assumptions. The temperature inside the core reaches about 10,000 degrees, so it is not yet possible to get to it even with the best technology.
The core lies at a depth of 2900 kilometers. It is generally accepted that it has two layers - external and internal. Together they have an average radius of 3.5 thousand kilometers and are composed of iron and nickel. It is assumed that the core may contain sulfur, silicon, hydrogen, carbon, phosphorus.
Its inner layer is in a solid state due to enormous pressure. The size of its radius is 70% of the radius of the moon, which is about 1200 kilometers. The outer core is in a liquid state. It consists not only of iron, but also of sulfur and oxygen.
The temperature of the outer core ranges from 4 to 6 thousand degrees. Its fluid is constantly moving and thereby affects the Earth’s magnetic field.
Mantle
The mantle envelops the core and represents an average level in the structure of the planet. It is not available for direct research and is studied using geophysical and geochemical methods. It occupies about 83% of the planet. Under the surface of the oceans, its upper boundary runs at a depth of several kilometers; under the continents, these figures increase to 70 kilometers.
It is divided into upper and lower parts, between which passes a layer of Golitsin. Like the lower layers of the Earth, the mantle has a high temperature - from 900 to 4000 degrees. By its consistency, it is viscous, while its density fluctuates depending on chemical changes and pressure.
In composition, the mantle is similar to stone meteorites. It contains silicates, silicon, magnesium, aluminum, iron, potassium, calcium, as well as grospidity and carbonatite, which are not found in the earth's crust. Under the influence of strong temperatures in the lower level of the mantle, many minerals decompose into oxides.
Outer layer of the earth
The surface of Mokhorovichich is located above the mantle, denoting the boundary between the shells of different chemical composition. In this part, the speed of seismic waves increases sharply. The upper layer of the Earth is represented by the crust.
The outer part of the shell is in contact with the hydrosphere and the atmosphere of the planet. Under the oceans, it is much thinner than on land. About 3/4 of it is covered by water. The structure of the crust is similar to the crust of the planets of the earth group and partially of the moon. But only on our planet is it divided into continental and oceanic.
The oceanic crust is relatively young. Most of it is represented by basaltic rocks. The layer thickness in different parts of the ocean is from 5 to 12 kilometers.
The continental crust consists of three layers. Below are granulites and other similar metamorphic rocks. Above them is a layer of granite and gneiss. The upper level is represented by sedimentary rocks. The continental crust contains 18 elements, including hydrogen, oxygen, silicon, aluminum, iron, sodium and others.
Lithosphere
One of the spheres of the geographical shell of our planet is the lithosphere. It combines such layers of the Earth as the upper mantle and the crust. It is also defined as the hard shell of the planet. Its thickness is from 30 kilometers on the plains to 70 kilometers in the mountains.
The lithosphere is divided into stable platforms and mobile folded areas, in the areas of which mountains and volcanoes are located. The upper layer of the hard shell formed magma flows, which broke through the earth's crust from the mantle. Due to this, the lithosphere consists of crystalline rocks.
It is subject to external processes of the Earth, such as weathering. The processes in the mantle do not subside and are manifested by volcanic and seismic activity, the movement of lithospheric plates, and mountain building. This, in turn, also affects the structure of the lithosphere.