Earth's mantle is part of the geosphere, located between the bark and the core. It has a large proportion of the entire substance of the planet. The study of the mantle is important not only in terms of understanding the inner, it can shed light on the formation of the planet, give access to rare compounds and rocks, help understand the mechanism of earthquakes and however, information about the composition and features of the mantle is not easy. Board wells so deeply people do not know how. Earth's mantle is mainly now being studied using seismic waves. And also by modeling under the laboratory conditions.

Earth structure: mantle, core and bark

According to modern ideas, the inner structure of our planet is divided into several layers. The top is the bark, then lie the mantle and the core of the Earth. Cora - a solid shell, dividing oceanic and continental. The land mantle is separated from her the so-called Mochorovichi border (by the name of the Croatian seismologist who has established its location), which is characterized by the jump-shaking increase in the rates of longitudinal seismic waves.

The mantle is approximately 67% of the mass of the planet. According to modern data, it can be divided into two layers: upper and lower. The first is also isolated a layer of a golitsyn or an average manta, which is a transition zone from the top to the bottom. In general, the mantle extends at a depth of 30 to 2900 km.

The core of the planet, according to the presentation of modern scientists, consists mainly of iron crystal alloys. It is also divided into two parts. The inner core is solid, its radius is estimated at 1,300 km. External - liquid, has a radius of 2,200 km. Between these parts allocate the transition zone.

Lithosphere

The bark and the upper mantle of the Earth are combined by the concept of "lithosphere". This is a solid shell having stable and mobile areas. The solid shell of the planet consists of which, as assumed, moves along an asthenosphere - a rather plastic layer, which is likely to be viscous and highly heated fluid. It is part of the upper mantle. It should be noted that the existence of an asthenosphere as a continuous viscous shell is not confirmed by seismological studies. The study of the structure of the planet allows you to select several similar layers placed vertically. In the horizontal direction of the asthenosphere, apparently, is constantly interrupted.

Methods of studying the mantle

The layers lying below the bark are not allowed to explore. Huge depth, constant increase in temperature and increasing density are a serious problem for obtaining information about the composition of the mantle and kernel. However, it is still possible to present the structure of the planet. When studying the mantle, geophysical data becomes the main sources of information. The speed of seismic waves, the characteristics of the electrical conductivity and the force of gravity allow scientists to make assumptions about the composition and other features of the underlying layers.

In addition, some information can be obtained from and fragments of mantle breeds. The latter includes diamonds that can even tell a lot about the lower mantle. Mantle breeds and in the earth's crust are found. Their study helps to understand the composition of the mantle. However, they will not replace the samples extracted directly from the deep layers, since as a result of various processes occurring in the crust, their composition is different from the mantle.

Earth Mantle: Composition

Another source of information about what is mantle - meteorites. According to modern ideas, chondrites (the most common group of meteorites) is close to the earth's mantle.

It is assumed that it contains elements that were in solid state or entered into a solid connection in the process of forming the planet. These include silicon, iron, magnesium, oxygen and some others. In the mantle, they, uniting with forming silicates. In the upper layer, magnesium silicates are located, the amount of iron silicate is growing with depth. In the lower mantle, these compounds are decomposed on oxides (SiO 2, MGO, FEO).

Of particular interest to scientists are breeds that are not found in the earth's crust. As expected, in the mantle of such compounds (brins, carbonatites, and so on) a lot.

Layers

Let us dwell on the length of the layers of the mantle. According to the ideas of scientists, the top of them takes the range of about 30 to 400 km from the following, there is a transition zone that goes deep into another 250 km. The next layer is lower. His border is located at a depth of about 2900 km and comes into contact with the external core of the planet.

Pressure and temperature

With the promotion of the planet deep into the temperature, the temperature rises. Earth's mantle is under the action of extremely high pressure. In the asthenosphere zone, the effect of temperature outweighs, therefore, the substance is in the so-called amorphous or semi-flap. Deeper under the influence of pressure, it becomes solid.

Studies of mantle and borders Mochorovichich

The earth's mantle does not give peace by scientist for quite a long time. In laboratories above the rocks, experiments are presumably included in the upper and lower layer, allowing to understand the composition and features of the mantle. So, Japanese scientists have found that the bottom layer contains a large amount of silicon. In the upper mantle there are water reserves. It comes from the earth's crust, and also penetrates from here to the surface.

Of particular interest is the surface of Mochorovichich, the nature of which is incomprehensible to the end. Seismological studies suggest that at the level of 410 km under the surface there is a metamorphic change in rocks (they become more dense), which manifests itself in a sharp increase in the velocity of the waves. It is assumed that basalt rocks in the area are turned into an eclogite. In this case, an increase in the density of the mantle is about 30%. There is another version according to which the reason for changing the rate of seismic waves lies in the change in the composition of rocks.

Tickie hackken

In 2005, a specially equipped ship Chikyu was built in Japan. His mission is to make a record deep well at the bottom of the Pacific Ocean. Scientists suggest to take samples of the rocks of the upper mantle and the border of Mochorovichich to get answers to many questions related to the structure of the planet. The project is scheduled for 2020.

It should be noted that scientists did not just turn their eyes precisely to oceanic. According to research, the thickness of the bark at the bottom of the seas is significantly less than on continents. The difference is significant: under the thickness of water in the ocean to magma, it is necessary to overcome in some 5 km, whereas on land, this figure increases to 30 km.

Now the ship is already working: samples of deep coal layers are obtained. The implementation of the main goal of the project will make it possible to understand how the land's mantle is arranged, which substances and elements make up its transition zone, as well as find out the lower limit of the spread of life on the planet.

Our idea of \u200b\u200bthe structure of the Earth is not yet complete. The reason for this is the complexity of penetration in the subsoil. However, technical progress does not stand still. Achievements of science suggest that in the near future we will know about the characteristics of the mantle much more.

Line UMK "Classical Geography" (5-9)

Geography

The internal structure of the Earth. Mir of amazing secrets in one article

The inner structure of the Earth

Planet Earth consists of three main layers: earth crust, mantle and nuclei. You can compare the globe with an egg. Then the egg shell will be an earthly boron, an egg white - a mantle, and yolk - core.

The upper part of the Earth is called lithosphere(Translated from the Greek "Stone Ball"). This is a solid shell of the globe, which includes the earth's crust and the upper part of the mantle.

The training manual is addressed to students of grade 6 and is included in the CMD "Classical Geography". Modern design, a variety of questions and tasks, the possibility of parallel work with the electronic form of the textbook contribute to the effective learning learning material. The training manual complies with the Federal State Educational Standard of the Basic General Education.

Earth's crust

The crust is a stone shell that covers the entire surface of our planet. Under the oceans, its thickness does not exceed 15 kilometers, and on the mainland - 75. If you return to an analogy with the egg, then the earth's crust in relation to the entire planet thinner than the egg shell. This layer of land accounts for only 5% of the volume and less than 1% of the mass of the entire planet.

As part of the earth's crust, scientists have discovered silicon oxides, alkali metal, aluminum and iron. The bark under the oceans consists of a sedimentary and basalt layers, it is heavier continental (mainland). While the shell covering the continental part of the planet has a more complex structure.

Three layers of continental terrestrial crust are isolated:

sedimentary (10-15 km mostly sedimentary breeds);

granite (5-15 km of metamorphic rocks, according to properties similar to granite);

basalt (10-35 km of magmatic breeds).

Mantle

Under the earth's crust is the mantle ( "Cover, cloak"). This layer has a thickness of up to 2900 km. It accounts for 83% of the total volume of the planet and almost 70% of the mass. It consists of mantle of heavy minerals rich in iron and magnesium. This layer has a temperature of over 2000 ° C. Nevertheless, most of the substance of the mantle retains a solid crystalline state due to huge pressure. At a depth of 50 to 200 km, the moving upper layer of the mantle is located. It is called an asthenosphere ( "Impossile Sphere"). Asthenosphere is very plastic, precisely because of it there is an eruption of volcanoes and the formation of mineral deposits. In the thickness of the asthenosphere reaches from 100 to 250 km. The substance that penetrates the asthenosphere into the earth's bark and is poured sometimes to the surface, called magma ("Messa, thick ointment"). When Magma froze on the ground surface, it turns into Lava.

Core

Under the mantle, as if under the bedspread, there is a terrestrial core. It is located 2900 km from the surface of the planet. The kernel has a ball shape with a radius of about 3,500 km. Since people still failed to get to the nucleus of the Earth, the scientists are building guesses about its composition. Presumably, the kernel consists of iron with an admixture of other elements. This is the tight and heavy part of the planet. It accounts for only 15% of the volume of land and as much as 35% of the mass.

It is believed that the kernel consists of two layers - a solid internal nucleus (by a radius of about 1,300 km) and liquid external (about 2,200 km). The inner core seems to float in the external liquid layer. Because of this smooth movement around the Earth, its magnetic field is formed (it protects the planet from hazardous space radiation, and the compass arrow reacts to it). The kernel is the hottest part of our planet. For a long time it was believed that the temperature reaches it, presumably, 4000-5000 ° C. However, in 2013, scientists conducted a laboratory experiment, during which the melting point of iron was determined, which is probably part of the inner earth's nucleus. It turned out that the temperature between the inner solid and external liquid nucleus is equal to the temperature of the surface of the Sun, that is, about 6000 ° C.

The structure of our planet is one of the many unsolved secrets of secrets. Most of the information about it is obtained by indirect methods, no one scientist has failed to produce samples of the earth's core. The study of the structure and composition of the Earth is still conjugate with insurmountable difficulties, but researchers do not surrender and are looking for new ways to extract reliable information about the planet Earth.

When studying the topic "Interior structure of the Earth", students may have difficulties with memorizing titles and order of the globe layers. Latin names will be much easier to remember if the children will create their own earth model. You can offer students to perform a globe model from plasticine or tell about its device on the example of fruits (peel - earth bark, flesh - mantle, bone - core) and items that have a similar structure. Textbook O.A. Climanova will help in the lesson, where you will find colorful illustrations and detailed information on the topic.

\u003e What is the Earth?

Domestic structure of land. Examine the structure of the planet: bark, core, mantle, from which chemical elements the land, history of research, geology.

Earth is something more than we manage to see from our position. If it were possible to cut it in half, then you would be very surprised. We rush to search for new worlds, but we still do not know much about our.

But the seismology managed to open the structure of the Earth and show layers. Each is endowed with its properties, characteristics and composition. And all this affects the earth's processes. What is the earth?

Modern theory

The internal space of the planet is differentiated. That is, the structure (as well as the remaining planets) is represented by layers. Remove alone and get to the next one. Moreover, everyone will have its own temperature and chemical composition.

Our understanding of the layers of the planet is based on the results of seismological monitoring. It accommodates the study of sound waves created by an earthquake, as well as the analysis of how passing through various layers slows down their pace. Changes in seismic velocity lead to refraction.

They are used together with transformations in gravitational and magnetic fields and experiments with crystalline solids that imitate pressure and temperature indicator in the depths of the planet.

Research

Back in ancient times, mankind tried to figure out the Earth. The first attempts did not even relate to science. These were the legends and myths associated with Divine intervention. However, several theories spread among the population.

You could hear about flat land. This view was told in Mesopotamian culture. The planet was depicted as a flat disk, a furrowing ocean. Maya also considered it flat, but there were four jaguars on the corners that held the sky. Persians saw the cosmic mountain, and the Chinese had a four-sided cube.

In the 6th century BC e. The Greeks were inclined to a rounded form, and in the 3rd century BC. e. The idea of \u200b\u200bspherical land gained the soil under the legs and the first evidence base. At the same time, scientists start contact with geological studies, and philosophers consider minerals and metals.

But the real shift occurred only in the 16-17th centuries. Edmund Galeigh in 1692 suggested the theory of "Earth Earth". He believed that inside there is a cavity, that is, a certain kernel, whose thickness takes 800 km.

Between these spheres there is an air gap. In order not to occur the effect of friction, the inner sphere should be held in place in place. The model displayed two concentric shells around the kernel. The diameter corresponded to Mercury, Venus and Mars.

Galley was based on the density of the Moon and the Earth, put forward by Isaac Newton in 1687. Then scientists decided to consider the accuracy of the Bible. Researchers were important to calculate the real age of the planet and discover evidence of the flood. Here and began to consider fossil and generate a system for classifying the dating of layers.

In 1774, Abraham Werner presented in his writings a detailed system of identifying certain minerals based on their external characteristics.

In 1741, the first place for geology appeared in the National Museum of the Natural History of France. After 10 years, the term "geology" entered the source.

In the 1770s. Chemical analyzes are published in the first place in research. One of the important tasks was the study of places for the presence of liquid flooding in the past (flood). In the 1780s. There were those who believed that the layers were not created because of the water, but at the expense of fire. Followers were called plutonists. They believed that the planet was formed due to solidification of molten masses. And all this happened extremely slow. From here it flows out that the planet is much older than the said in the Bible.

In the 19th century, the industrial revolution was strongly influenced by the geology, as well as the concept of stratigraphic column - rock formations are arranged in the order of their appearance in time. Scientists have become aware that the age of the fossils can be calculated geologically (the more deeper, the older).

Researchers have the opportunity to go swimming to expand the horizons and compare finds in different places. Among such luckyrs were Charles Darwin, recruited by the captain of the Beagle ship.

The giant fossils found by him made a geologist from him, and his theories about the causes of disappearance led to the most important work "On the origin of species", written in 1859.

Scientists have increased their knowledge and created the geological maps of the Earth. They have already calculated the earthly age in millions of concepts, and not thousands. But technology development helped to move the remnants of dogmatic representations.

In the 20th century, radiometric dating appeared. Then they thought that the planetary age reaches 2 billion years. In 1912, Alfred Vegegen put forward the theory of continental drift. That is, once all the continents were one whole. Later, this was confirmed by geological analysis of samples.

The theory of slab tectonics arose from the study of the oceanic bottom. Geophysical data demonstrate the lateral movement of the continents, and the oceanic cort is younger than continental.

In the 20th century, seismology was actively developed, the study of earthquakes and the passage of waves through the Earth. It was this that helped to understand and get to the nucleus.

In 1926, Harold Jeffis said that the earth's crud is liquid, and in 1937, Inge Lemann expanded this theory, supplement that inside the liquid core there is a solid solid.

Ground layers

Earth can be divided mechanically or chemically. The first method is studying liquid states. A lithosphere, an asthenosphere and mesosphere, external and internally nucleus appear here. But the chemical method has gained great popularity, found a bark, mantle and core.

The inner core is solid, and external liquid. The lower mantle dwells under strong pressure, so it has a lower viscosity than the top. All differences are caused by processes accompanying planetary development within 4.5 billion years. Let's carefully study the inner structure of the Earth.

Bark

This is an external, cooled and frozen layer. It extends 570 km and represents only 1% of the planetary volume.

Thickest parts are the oceanic bark underlying the ocean pools (5-10 km), and the more dense is continental. The upper part of the mantle and the earth is a lithosphere, covering 200 km. Most of the cliffs formed 100 million years ago.

Upper mantle

It takes 84% \u200b\u200bof the volume and performs mostly solid, but sometimes behaves like a viscous liquid. It begins with the "surface of Mochorovichich" - 7-35 km and deepened by 410 km.

Movement in the mantle is reflected on the movement of tectonic plates. The process is caused by heat from depth. This is exactly what leads to earthquakes and the formation of mountain ranges.

The temperature rises by 500-900 ° C. The layer at a depth of 410-660 km is considered a transition zone.

Lower mantle

The temperature at a depth of 660-2891 km is capable of reaching 4000 ° C. But the pressure here is too strong, therefore viscosity and melting are limited. This layer knows little, but it is believed that seismically homogeneous.

External kernel

This is a liquid shell with a thickness of 2,300 km, and within a radius covers 3400 km. Here the density is much higher - 9900-12200 kg / m 3. It is believed that the kernel is presented with 80% of iron, as well as nickel and other light elements. There is no strong pressure, so it does not solidify, although according to the composition resembles the inner core. Temperature - 4030 ° C.

In the liquid kernel, due to temperature and turbulence, Dynamo is created that affects the magnetic field.

Inner kernel

What elements are the earth kernel? Represented by iron and nickel, and within a radius covers 1220 km. Density - 12600-13000 kg / m 3, which hints at the presence of heavy elements (platinum, gold, palladium, tungsten and silver).

The temperature here grows to 5400 ° C. Why are solid metals remain liquid? Because the melting point is extremely high, as well as pressure. Internally is not strongly connected with solid mantia, so it is believed that it rotates faster than the planet itself.

It is also believed that the inner core possesses layers separated by a transition zone with a thickness of 250-400 km. The lowest layer is capable of stretching 1180 km in diameter. Scientists testify to the dynamics, due to which the kernel is expanding 1 mm per year.

As you can see, our planet is an amazing and complete mysteries place. It still lies with warmth, accumulated billions of years ago. And this is not a dead body, but a dynamic object that is constantly changing.

Under the earth's crust is the following layer, referred to as Mantia. He surrounds the core of the planet and has a thickness of almost three thousand kilometers. The structure of the land mantle is very complex, therefore requires a detailed study.

Mantle and her features

The name of this shell (geospheres) comes from the Greek word denoting the cloak or bedspread. In fact, the mantle, as if the bedspread envelops the kernel. It accounts for about 2/3 of the mass of the earth and approximately 83% of its volume.

It is believed that the membrane temperature does not exceed 2500 degrees Celsius. Its density in different layers is significantly different: in the upper part it is up to 3.5 t / cubic meters, and in the lower - 6 tons / cubic meters. Mantle of hard crystalline substances (heavy minerals rich in iron and magnesium). An exception is only an asthenosphere, which is a semi-flap.

Structure shell

Now consider the structure of the land mantle. The geosphere consists of the following parts:

• upper mantle, thickness of 800-900 km;
• asthenosphere;
• lower mantle, thickness about 2000 km.

The upper mantle is part of the shell, which is located below the earth's crust and enters the lithosphere. In turn, it is divided into an asthenosphere and a layer of a golitsin, which is characterized by an intense increase in seismic waves. This part of the Earth's mantle affects such processes as tactical movements of plates, metamorphism and magmatism. It is worth noting that the structure is different depending on what kind of tectonic object it is located.

Asthenosphere. The name of the middle layer of the shell itself is translated from the Greek, like a "weak ball". The geosphere believed to the upper part of the mantle, and sometimes isolated in a separate layer, is characterized by a reduced hardness, durability and viscosity. The upper boundary of the asthenosphere is always below the extreme line of the earth's crust: under the continents - at a depth of 100 km, under the seabed - 50 km. The lower line is located at a depth of 250-300 km. Asthenosphere is the main source of magma on the planet, and the movement of amorphous and plastic substances is considered the cause of tectonic movements in horizontal and vertical planes, magmatism and metamorphism of the earth's crust.

About the bottom of the mantle scientists know a little. It is believed that on the border with the kernel there is a special layer d, resembling an asthenosphere. It is characterized by a high temperature (due to the proximity of the hot core) and the inhomogeneity of the substance. The masses include iron and nickel.

The composition of the land mantle

In addition to the structure of the land mantle, its composition is also interesting. The geosphele creates olivine and ultrasound (peridotitis, perovskites, dunits), but there are also the main breeds (eclogites). It has been established that in the shell contains rare varieties that are not found in the earth's crust (globiditis, flogopite peridotites, carbonatites).

If we talk about the chemical composition, then in the mantle in different concentrations contain: oxygen, magnesium, silicon, iron, aluminum, calcium, sodium and potassium, as well as their oxides.

Mantle and her study - video