The lithosphere of planet Earth is a solid shell globe, which includes multilayer blocks called lithospheric plates. As Wikipedia points out, translated from Greek language this is a "stone ball". It has a heterogeneous structure depending on the landscape and the plasticity of the rocks located in the upper layers of the soil.

The boundaries of the lithosphere and the location of its plates are not fully understood. Modern geology has only a limited amount of data about the internal structure of the globe. It is known that lithospheric blocks have boundaries with the hydrosphere and atmospheric space of the planet. They are in close relationship with each other and touch each other. The structure itself consists of the following elements:

1. Asthenosphere. A layer with reduced hardness, which is located in the upper part of the planet relative to the atmosphere. In places it has very low strength and is prone to fractures and ductility, especially if groundwater flows within the asthenosphere.
2. Mantle. This is a part of the Earth called the geosphere, located between the asthenosphere and the inner core of the planet. It has a semi-liquid structure, and its boundaries begin at a depth of 70–90 km. It is characterized by high seismic velocities, and its movement directly affects the thickness of the lithosphere and the activity of its plates.
3. Core. The center of the globe, which has a liquid etiology, and the preservation of the magnetic polarity of the planet and its rotation around its axis depends on the movement of its mineral components and the molecular structure of molten metals. The main component of the earth's core is an alloy of iron and nickel.

What is the lithosphere? In fact, it is the solid shell of the Earth, which acts as an intermediate layer between fertile soil, mineral deposits, ores and the mantle. On the plain, the thickness of the lithosphere is 35–40 km.

Important! In mountainous areas this figure can reach 70 km. In the area of ​​such geological heights as the Himalayan or Caucasus Mountains, the depth of this layer reaches 90 km.

Structure of the Earth

Layers of the lithosphere

If we consider the structure of lithospheric plates in more detail, they are classified into several layers, which form the geological features of a particular region of the Earth. They form the basic properties of the lithosphere. Based on this, the following layers of the hard shell of the globe are distinguished:

1. Sedimentary. Covers most of the top layer of all earth blocks. It mainly consists of volcanic rocks, as well as remains organic matter, which over many millennia have decomposed into humus. Fertile soils are also part of the sedimentary layer.
2. Granite. These are lithospheric plates located in constant movement. They are predominantly composed of super-strong granite and gneiss. The last component is a metamorphic rock, the vast majority of which is filled with minerals such as potassium spar, quartz and plagioclase. Seismic activity of this layer of solid shell is at the level of 6.4 km/sec.
3. Basaltic. It is predominantly composed of basalt deposits. This part of the Earth's solid shell was formed under the influence of volcanic activity back in ancient times, when the formation of the planet took place and the first conditions for the development of life arose.

What is the lithosphere and its multilayer structure? Based on the above, we can conclude that this is the solid part of the globe, which has a heterogeneous composition. Its formation took place over several millennia, and high-quality composition depends on what metaphysical and geological processes took place in a particular region of the planet. The influence of these factors is reflected in the thickness of lithospheric plates and their seismic activity in relation to the structure of the Earth.

Layers of the lithosphere

Oceanic lithosphere

This type of earth's shell differs significantly from its mainland. This is due to the fact that the boundaries of lithospheric blocks and the hydrosphere are closely intertwined, and in some parts of it the water space is distributed beyond the surface layer of lithospheric plates. This applies to bottom faults, depressions, cavernous formations of various etiologies.

Oceanic crust

That is why oceanic plates have their own structure and consist of the following layers:

• marine sediments that have a total thickness of at least 1 km (in the deep ocean, they may be completely absent);
• secondary layer (responsible for the propagation of medium and longitudinal waves moving at speeds of up to 6 km/sec, takes an active part in the movement of plates, which provokes earthquakes of varying power);
• the lower layer of the solid shell of the globe in the area where the ocean floor is located, which is mainly composed of gabbro and borders the mantle (average seismic wave activity is from 6 to 7 km/sec.).

A transitional type of lithosphere is also distinguished, located in the area of ​​oceanic soil. It is characteristic of island zones formed in an arc. In most cases, their appearance is associated with the geological process of movement of lithospheric plates, which were layered on top of each other, forming this kind of irregularities.

Important! A similar structure of the lithosphere can be found on the outskirts of the Pacific Ocean, as well as in some parts of the Black Sea.

Useful video: lithospheric plates and modern relief

Chemical composition

The lithosphere is not diverse in terms of its content of organic and mineral compounds and is mainly presented in the form of 8 elements.

Most of these are rocks that were formed during a period of active eruption of volcanic magma and plate movement. The chemical composition of the lithosphere is as follows:

1. Oxygen. Occupies at least 50% of the entire structure of the solid shell, filling its faults, depressions and cavities formed during the movement of plates. Plays a key role in the balance of compression pressure during geological processes.
2. Magnesium. This is 2.35% of the Earth's solid shell. Its appearance in the lithosphere is associated with magmatic activity in the early periods of the planet’s formation. It is found throughout the continental, marine and oceanic parts of the planet.
3. Iron. A rock that is the main mineral of lithospheric plates (4.20%). Its main concentration is in the mountainous regions of the globe. It is in this part of the planet that the highest density of this chemical element is found. It is not presented in pure form, but is found in lithospheric plates mixed together with other mineral deposits.

Lithosphemra (from the Greek lYaipt - stone and utsbYasb - ball, sphere) is the hard shell of the Earth. Comprises earth's crust and the upper part of the mantle, to the asthenosphere, where the velocities of seismic waves decrease, indicating a change in the plasticity of the rocks. In the structure of the lithosphere, mobile regions (folded belts) and relatively stable platforms are distinguished.

Scheme internal structure land

Diagram of the continental and oceanic crust



The main landforms on land are mountains and plains.

Classifications of landforms:

Taking into account the properties of the relief, several classifications have been developed:

1) Morphological classification, taking into account the size of landforms

Planetary forms are continents, mobile belts, ocean floors, and mid-ocean ridges;

Megaforms are parts of planetary forms, i.e. plains and mountains;

Macroforms are parts of megaforms: mountain ranges, large valleys and depressions;

Mesoforms are medium-sized forms: beams, ravines;

Microforms are irregularities that complicate the surface of mesoforms: karst sinkholes, gullies;

Nanoforms are very small irregularities that complicate meso- and microforms: hummocks, ripples on the slopes of dunes, etc.

2) Classification according to genetic characteristics

There are two classes:

• 1. Forms formed as a result of the activity of internal, endogenous forces;
• 2. Forms formed due to exogenous, external forces.

The first class includes two subclasses: a) forms associated with the movement of the earth’s crust; b) forms associated with volcanic activity. The second class includes: a) fluvial forms; b) aeolian forms; c) glacial; d) karst, etc.

3) Morphogenetic classification:

It was first proposed at the beginning of the 20th century by Engel. He identified three categories of relief:

• 1. Geotextures;
• 2. Morphological structures;
• 3. Morphosculptures.

In this case, the following stand out:

Geotextures are the largest landforms on Earth: planetary and megaforms. They are created by cosmic and planetary forces.

Morphostructures are large forms of the earth's surface that are created under the influence of endogenous and exogenous processes, but with the leading and active role of tectonic movements.

Morphosculptures are medium and small relief forms (meso-, micro- and nanoforms), created with the participation of endo- and exogenous forces, but with the leading and active role of exogenous forces.

4. Classification of relief by age

The development of the relief of any territory, as shown by the American geomorphologist W. Davis, occurs in stages. The age of a relief can be understood as certain stages of its development. For example, the formation of a river valley after the retreat of a glacier: first, the river cuts into the underlying rocks, there are many irregularities in the longitudinal profile, and there is no floodplain. This is the youth stage of the river valley. Then a normal profile is formed, and a river floodplain is formed. This is the maturity stage of the valley. Due to lateral erosion, the floodplain expands, the river flow slows down, and the channel becomes winding. The old age stage begins in the development of the river valley.

W. Davis took into account a complex of morphological and dynamic characteristics and identified three stages: youth, maturity and old age of the relief.

Geosynclines are mobile belts of the lithosphere, in which, during the tectonic cycle, forces of extension and subsidence are sequentially manifested, then compression and uplift of the earth's crust, as well as accumulation and dislocation, metamorphism and granitization of sedimentary rocks and the transformation of geosynclinal areas into platform and oceanic areas into continental.

Geosynclines have the following characteristics:

• 1) Colossal sizes (many thousands of kilometers in length and up to a thousand kilometers in width);
• 2) Shape (straight-line, arc-shaped and ring);
• 3) Increased permeability of the lithosphere for endogenous heat flows, as well as magmatic melts and other fluids. The bulk of intrusive and effusive bodies are confined to geosynclinal areas;
• 4) Morphotectonic expression. At the first stage of development, geosynclines are represented by marine depressions, and at the final stage - by continental high-mountain folded systems;
• 5) Specific formations;
• 6) Sharp changes in the thickness of sedimentary rocks along the strike of geosynclines. The total thickness of precipitation in some places can reach 20-25 km;
• 7) Processes of dislocation, metamorphism and granitization of sedimentary rocks.

In the structural division of geosynclines, the element of the first magnitude is the geosynclinal belt - a mobile zone of the lithosphere of planetary dimensions, experiencing tectogenesis of a constructive direction. Large geosynclinal belts generally separate and frame ancient platforms and are thought to have begun to form in the Late Proterozoic. earth crust continental platform

Platforms are sedentary large isometric blocks of the earth's crust or a foundation of igneous and metamorphic rocks, a sedimentary cover, characterized by relatively low permeability of the earth's crust, low seismicity and volcanism.

Platforms are divided into continental (cratons) and oceanic. Their main difference is:

• 1) heterogeneous composition of the second layer of the crust;
• 2) a large difference in the layer-by-layer and total thickness of the lithosphere;
• 3) in the unequal internal structure of these platforms;

The sedimentary cover of platforms is characterized by horizontal or almost horizontal occurrence of layers, comparative constancy of their composition, consistency of thickness and a set of specific platform formations.

Continental platforms are like the cores of continents and occupy large parts of the continents' area. Continental platforms are composed of typical continental crust, 35-40 km thick. Within the platforms, the thickness of the lithosphere reaches 150 - 200 km, and in some cases 400 km. A significant part of the platforms is covered with a non-metamorphosed sedimentary cover, 3 - 5 km thick, and in bends and depressions the thickness can reach 10 - 12 km, and in some cases 25 km. The sedimentary cover may include covers of plateau basalts, and sometimes more acidic volcanics. Where the platforms are not covered, a foundation composed of metamorphic rocks comes to the surface varying degrees metamorphism, as well as intrusive igneous rocks, mainly granites.

The platforms have a flat terrain (lowland or plateau). Some areas of the platforms may be covered by a shallow epicontinental sea (the White and Azov Seas). The platforms are characterized by low modern vertical movements, very weak seismicity, absence of volcanic activity and reduced heat flow (compared to the average terrestrial).

Continental platforms are divided into ancient and young.

The Ancients are the most typical platforms with Precambrian, mainly Early Precambrian basements and constitute the oldest central parts of the continents. Ancient platforms include the North American, East European, Siberian, and Sino-Korean. These platforms make up the northern row of platforms. Next come South American, African, Indian, Australian, Antarctic, which occupy the southern row. A separate group includes the South China Platform, which Japanese geologists call the Yangtze. The basement of these platforms is dominated by Archean formations. They are followed by the Early Proterozoic, Middle Proterozoic and Upper Proterozoic.

The ancient platforms have a polygonal outline and are separated from adjacent strike-slip and thrust structures by forward troughs. These troughs are superimposed on the lowered edges of the platforms, or are directly tectonically overlain by their overthrust peripheral zones. Along the periphery of the East European Platform, both types of such relations are observed.

Thus, the main features of ancient continental platforms are:

• 1) two-story structure (the foundation is composed of Precambrian rocks and sedimentary cover);
• 2) a large distribution of sedimentary cover of consistent thickness and identical composition;
• 3) discontinuous folding;
• 4) the absence of a direct inherited connection between the structures of the cover and the folding of the foundation.

Young continental platforms occupy a significantly smaller area of ​​the continents (about 5%) and are located mainly along the periphery of the continents or between ancient platforms.

Young platforms include the Central European and Western European, East Australian, and Patagonian platforms. They are located on the outskirts of continents. The West Siberian platform refers to platforms located between ancient platforms.

The foundation of young platforms is composed mainly of sedimentary-volcanic rocks of Phanerozoic age, which are weakly metamorphosed. Granites and other intrusive formations play a subordinate role in the composition of the basement and therefore the foundation of young platforms is called not crystalline, but folded. Therefore, the foundation of young platforms differs from the foundation of the sedimentary cover only in its high dislocation. In this regard, depending on the age of the final folding of the foundation of young platforms, all plateaus or parts thereof are divided into epicaledonian, epihercynian, and epicimmerian.

The sedimentary cover of young platforms is composed of Jurassic or Cretaceous-Quaternary deposits. Thus, on the Epihercynian platforms the cover begins with the Upper Permian, and on the Epicaledonian platforms - with the Upper Devonian. Due to the fact that young platforms are more covered with sedimentary cover than ancient ones, in the literature they are often called slabs.

Thus, young platforms are characterized by the following features:

• 1) three-story structure: foundation, intermediate complex and sedimentary cover;
• 2) young platforms are located on the periphery of geosynclinal belts and at the junction of ancient platforms;
• 3) partial inheritance of the structural plan and type of folding of the base in the sedimentary cover;
• 4) the presence of both intermittent and linear type folding.

Tectonic structures underlying the territory	Landform	Minerals	Conclusion about the connection
Kola Peninsula	The relief of the Kola Peninsula consists of depressions, terraces, mountains, and plateaus. The peninsula's mountain ranges rise more than 800 meters above sea level. The plains of the Kola Peninsula are occupied by swamps and numerous lakes.	In terms of diversity of mineral species, the Kola Peninsula has no analogues in the world. About 1000 minerals were discovered on its territory - almost 1/3 of all known on Earth. About 150 minerals are found nowhere else. Deposits of apatite-nepheline ores (Khibiny), iron, nickel, platinum metals, rare earth metals, lithium, titanium, beryllium, building and jewelry stones (amazonite, amethyst, chrysolite, garnet, jasper, iolite, etc.), ceramic pegmatites , mica (muscovite, phlogopite and vermiculite - the world's largest reserves)
Ural Mountains	The Urals is a region where different landforms border. The Ural mountains are low. Only a few peaks reach a height of 1500 m. The highest peak of the Urals is Mount Narodnaya (1895 m). Mountains consist of several chains parallel to each other. The chains are divided lengthwise and crosswise by depressions along which rivers flow. In addition, they are badly damaged. There are many relatively flat surfaces here. But although the Ural Mountains are not high, they are still mountains. The largest cities of the Urals are located either on flat areas or at altitudes up to 400 m above sea level.	The Urals are a treasury of various minerals. Of the 55 types of important minerals that were developed in the USSR, 48 are represented in the Urals. For eastern regions The Urals are most characterized by deposits of copper pyrite ores (Gaiskoye, Sibaiskoye, Degtyarskoye deposits, Kirovgrad and Krasnouralsk groups of deposits), skarn-magnetite (Goroblagodatskoye, Vysokogorskoye, Magnitogorskoye deposits), titanium-magnetite (Kachkanarskoye, Pervouralskoye deposits), oxide nickel ores (Orsko-Khalilovsky group deposits) and chromite ores (deposits of the Kempirsay massif), confined mainly to the greenstone belt of the Urals, coal deposits (Chelyabinsk coal basin), placers and primary deposits of gold (Kochkarskoye, Berezovskoye) and platinum (Isovskiye). Here are located largest deposits bauxite (North Ural bauxite-bearing region) and asbestos (Bazhenovskoe). There are deposits on the western slope of the Urals and in the Urals coal(Pechora coal basin, Kizelovsky coal basin), oil and gas (Volga-Ural oil and gas region, Orenburg gas condensate field), potassium salts(Verkhnekamsk basin). The Urals are especially famous for their “gems” - precious, semi-precious and ornamental stones (emerald, amethyst, aquamarine, jasper, rhodonite, malachite, etc.). The depths of the mountains contain more than two hundred different minerals. The bowls of the St. Petersburg Hermitage, as well as the interior decoration and altar of the Church of the Savior on Spilled Blood, are made from Ural malachite and jasper.

The lithosphere is the solid shell of the planet, the name of which comes from the Greek word "lithos", meaning stone. The term was proposed by J. Burrell in 1916 and was initially used by him as a synonym for the earth's crust. Only a few years later it was proven that the structure of the Earth's lithosphere is more complex. It includes the following:

• Earth's crust;
• Mantle (upper layer).

Base Layers

The Earth's crust is a component of the lithosphere, which has a depth of 35–70 km under the continental landmass and 5–15 km under the ocean floor. It also consists of layers:

• Continental crust: sedimentary, granite, basalt layer;
• Oceanic: a layer of marine sediments (may be completely absent in some cases), a middle layer of basalt and serpentine, a lower layer of gabbro.

Almost the entire periodic table can be found in the composition of the earth's crust, only in different parts. Most of all it contains oxygen, iron, silicon, aluminum, sodium, magnesium, calcium and potassium. The earth's crust accounts for about 1% total mass the entire planet.

The mantle is the lower part of the lithosphere, the depth of which reaches 2900 km. It consists mainly of silicon, oxygen, iron, magnesium, and nickel. Inside it there is a special layer - the asthenosphere, created from a special substance. The solid shell of the earth includes that part of the mantle that is located before the asthenosphere. This is the lower boundary of the shell, while the upper one is located next to the atmosphere and hydrosphere, with which the lithosphere interacts, partially penetrating into them.

It is a mistake to classify the lithosphere as the core, a separate layer of the globe, which is located at a depth of 2900–6371 km and consists of hot iron and nickel.

Shell Features

Based on the structure of the Earth's lithosphere, it can be argued that it is a relatively fragile shell, since it is not monolithic. It is divided by deep faults into separate blocks (or plates), which move very slowly in a horizontal direction along the asthenosphere. Therefore, a distinction is made between relatively stable platforms and moving areas (folded belts).

The structure of the Earth's lithosphere today is the division of the planet's surface into seven large and several small plates. The boundaries between them are marked by zones of highest volcanic and seismic activity. In diameter, these elements of the lithosphere are 1–10 thousand km.

Isostasy

I would also like to dwell on isostasy, a phenomenon that scientists discovered while studying mountain ranges and the force of gravity at their base (mountains are formed at the junction of lithospheric plates). Previously it was believed that large uneven terrain increases the force of gravity in the region. However, it turned out that gravity is the same over the entire earth's surface. Massive structures are balanced somewhere deep in the Earth, in the upper mantle: the larger the mountain, the deeper it is buried in the lithosphere. For some time, the earth's crust may be out of balance under the influence of tectonic forces, but then it still returns to it.

Structure and composition of the earth (lithosphere).

Earth, unlike other planets solar system, has a strong magnetic field, which is due to the peculiarity of its geological structure. Thanks to probing the Earth's interior with seismic waves, it was possible to establish that it has a shell structure and a differentiated chemical composition.

There are three main concentrically located areas:

Each of the Earth's shells is open system, which has a certain autonomy and its own internal laws of development, but at the same time they closely interact with each other.

The Earth's crust is the top layer of the Earth's solid shell.

Average thickness (thickness) of the Earth's crust 35 km:

Under the oceans it is 5 – 12 km:

Under flat massifs 30 – 40 km;

Under mountain ranges 50 – 70 km.

The earth's crust forms 3 (three) layers:

- “sedimentary”;

- “granite”;

- “basalt”.

"Sedimentary layer" composed of sedimentary rocks formed due to the decomposition products of other rocks, as well as the remains of dead animals and plants. This layer almost completely covers the surface of the Earth.

The thickness of the “sedimentary layer” ranges from 0 to several kilometers, but in some places it reaches 15–25 km.

"Granite layer" absent under the oceans, on the continents it is composed of rocks such as granites, as well as gneisses and other metamorphic rocks. The Earth's crust of this type is called continental. Its average power:

Under the plains there are massifs of about 10 km;

Under mountain ranges it increases to 20–30 km.

"Basalt layer" lies below the “granite” chemical composition corresponds to rocks called basalts. Its average power:

Under flat massifs 25 – 30 km;

Under mountain ranges – increases slightly;

In areas of deep ocean basins, under a kilometer-long layer of sediment lies a “basalt layer”, the thickness of which is only 6 km, and in some places even less.

The earth's crust is composed mainly of 8 (eight) chemical elements: - oxygen – 50%; - silicon; - aluminum; - iron; - calcium; - magnesium; - sodium; - potassium.

More than half (50%) of the earth's crust consists of silicon dioxide Si O 2 and 14 - 15% aluminum oxide AL 2 O 3 in combination with magnesium, iron, calcium, etc. This is the “stone material” that is familiar to us. . The average density of the Earth's crust is 5510 kg/m3 or 2.6 - 2.9 g/cm3.





The composition of the bark and outer shells is continuously renewed.

Thus, due to weathering and demolition, the material of the continental surface completely renewed in 80–100 million years.

The earth's crust and the upper solid layer of the mantle form the so-called lithosphere from the Greek "lithos" - stone, "sphere" - layer.

The thickness of the lithosphere is on average 100 km, and on continents and under the oceans it differs and averages:

On continents 25 – 200 km;

Under the oceans 5 – 100 km.

The portion of the mantle underlying the lithosphere is called the asthenosphere. It is approximately 100 km thick and probably consists of molten rocks. The temperature of the mantle in the upper part of the asthenosphere is 1000 0 C. In relation to the size of the entire planet, the lithosphere is no thicker than an eggshell and makes up only 1.5 of its volume or 0.8% of its mass.

The lithosphere consists of approximately 15 (fifteen) rigid plates, of which 6 - 7 plates are large, which can collide, sink under each other, move over one another, and rub against one another.





Together with the plates they can move and continents. These plates are sometimes called platforms.

Lithospheric plate can be formed:

Continental lithosphere;

Oceanic lithosphere.

The plates of the Earth's crust are gradually moving in different directions at a relatively slow speed of up to 5 cm per year (about the same speed our fingernails grow).

The edges of the slabs are called borders. Scientists have not yet studied the causes of plate movement.

Constant activity asthenosphere sets tectonic plates in motion, they:

They come closer (diverge); - collide; - diverge; - interlock; - rub one against the other.

In case of a collision.

Ocean plates

One of the ocean plates goes under the other and melts, sinking into the mantle and being absorbed by it. Magma rushes upward through the lithosphere and a chain is formed near the boundary on the plate at the top volcanoes.

The descending plate forms a depression - the Mariana Trench - about 11 km deep in the Pacific Ocean.

Continental plates.

Where two plates collide head-on.

At the boundary between the oceanic and continental plates, the oceanic plate “sinks” under the continental plate, creating a deep depression or trench on the surface.

As the plate sinks deeper and deeper into the mantle, it begins to melt. The crust of the upper plate is compressed and on it grow up, some of them represent mountains, volcanoes in the case of plate friction.

They rub their sides, moving either in the opposite direction or in the same direction, but at different speeds.

At the boundaries of these plates, the lithosphere is not destroyed.

Tremors can occur wherever rocks move along faults in the Earth's crust, but strong earthquakes tend to occur in well-defined zones. They occur most often in volcanic areas, such as the Pacific Ring of Fire.

In case of divergence or convergence of lithospheric plates.

If before the Earth was one continent, which divided into modern continents, then over the last 40 thousand years the continents began to unite. So Africa is creeping closer and closer to Europe.

This process causes the growth of the Alps and Pyrenees, as well as serious earthquakes in Italy, Greece, and Turkey.

The Mediterranean Sea is shrinking.

Scientists suggest that as a result of the rapprochement of Northern and South America towards Asia via Pacific Ocean, The Atlantic Ocean will expand.

Through Within a few hundred million years, a new continent, the Americas and Asia, may emerge.

The mantle (from the Greek “mantion” - blanket, cloak) is an intermediate shell between the Earth’s crust and the core, which is located at a depth of 6 – 70 to 2900 km and makes up the main volume of the planet.

The mass of the mantle makes up 31% of the Earth.

The mantle has a complex structure and is divided into:

- upper from 6 – 70 to 100 – 300 km – foci of deep-focus earthquakes form in it. They call her asthenosphere;

- average from 100 – 300 to 950 km;

- lower 950 – 2900 km.

The mantle is formed by various silicate compounds, the basis of which is silicon.

Mantle substances can be from solid to liquid molten and amorphous - plastic state. This is a semi-liquid - semi-viscous molten mass.

Depending on the power (depth) of the Earth increases:

Rock pressure and density;

Their temperature rises.

The sources of the Earth's internal thermal energy have not yet been sufficiently studied. The main ones are:

Radioactive decay of elements;

Redistribution of materials by density in the mantle, which is accompanied by the release of a significant amount of heat, the planet’s core is most likely the main source internal energy Earth, supplying heat to the mantle.

The core is like a “giant cauldron” without walls, in which the components of other geospheres are “aligned”.

More dense substances (compared to the Earth's crust) remain in the mantle.

Its density varies from – 3.3 g/cm 3 in the upper mantle at a depth of 50 – 980 km to 5.5 g/cm 3 at a depth of 950 – 2900 km.

Pressure at the upper boundary of the mantle is about 900,000 kPa or 9000 atm, and at the lower boundary it is about 140 million kPa or 1.4 million atm.

Having received warm from the core, the mantle heats up from 800 0 C at the top to 2250 0 C at a depth of 2900 km.

Earth's core

The core occupies the central region of the Earth's geoid, makes up 68% of the Earth's mass and is divided into two parts:

External;

Internal.

Outer core is located in the range of 2900 – 5100 km. There is no clear boundary between the outer and inner core. It is believed that the outer core consists of iron (52%) and a liquid mixture of solids formed by iron and sulfur (48%). The melting point of such a mixture is estimated to be approximately 3200 0 C. The substance of the outer core is “apparently” in a liquid state, but its density reaches 9.9 – 12.2 g/cm 3 . Pressure at the lower boundary of the outer core it reaches over 300 million kPa or 3 million atm.

The liquid state of the outer core is associated with ideas about the nature of terrestrial magnetism, believing that the Earth's magnetic field originates in the depths of the planet. The magnetic field is changeable. The position of the magnetic poles changes from year to year. Convincing experiments have shown that over the past 80 million years there has been not only a change in field strength, but also repeated systematic magnetization reversal, as a result of which the north and south magnetic poles of the Earth have changed places.

It is believed that the cause of this phenomenon is the mass of the liquid core, which moves as the Earth rotates around its axis.

Inner core is located in the range of 5100 – 6371 km. and is presumably in a solid state, and its density reaches 13.6 g/cm 3, and the pressure in the center of the Earth reaches 350 million kPa or 3.5 million atm.

The core is believed to be composed of iron (80%) and nickel (20%), which is identical in composition iron meteorites. This alloy, under the pressure of the earth’s interior, should have a temperature in the range of 2250 0 – 5000 0 C.

Lithosphere is the hard shell of the Earth.

Introduction

The lithosphere is important for all living organisms that live on its territory.

First of all, people, animals, insects, birds, etc. live on or inside land.

Secondly, this shell of the earth’s surface has enormous resources that organisms need for food and life.

Thirdly, it promotes the functioning of all systems, the mobility of the bark, rocks and soil.

What is the lithosphere

The term lithosphere consists of two words - stone and ball or sphere, which literally translated from Greek means the hard shell of the earth's surface.

The lithosphere is not static, but is in constant motion, which is why plates, rocks, resources, minerals, and water provide everything organisms need.

Where is the lithosphere located?

The lithosphere is located on the very surface of the planet, goes inside the mantle, to the so-called asthenosphere - a plastic layer of the Earth, consisting of viscous rocks.

What does the lithosphere consist of?

The lithosphere has three interconnected elements, which include:

• Crust (earth);
• Mantle;
• Core.



lithosphere structure photo

In turn, the crust and the uppermost part of the mantle - the asthenosphere - are solid, and the core consists of two parts - solid and liquid. The core has solid rock inside and the outside is surrounded by liquid substances. The crust consists of rocks that arose after the cooling and crystallization of magma.

Sedimentary rocks arise in various ways:

• When sand or clay breaks down;
• During the course chemical reactions in water;
• Organic rocks arose from chalk, peat, coal;
• Due to changes in the composition of rocks - completely or partially.

Scientists have found that the lithosphere consists of such important elements as oxygen, silicon, aluminum, iron, calcium, and minerals. According to its structure, the lithosphere is divided into mobile and stable, i.e. platforms and pleated belts.

A platform is usually understood as areas of the earth's crust that do not move as a result of the presence of a crystalline base. It can be either granite or basalt. In the middle of the continents there are usually ancient platforms, and at the edges there are those that arose later, in the so-called Precambrian period.

The folded belts arose after colliding with each other. As a result of such processes, mountains and mountain ranges arise. Most often they are located at the edges of the lithosphere. The most ancient ones can be seen in the center of the continent - this is Eurasia, or along the very edges, which is typical for America (North) and Australia.

Mountain formation occurs constantly. If a mountain range runs along a tectonic plate, this means that plates once collided here. There are 14 plates in the lithosphere, which makes up 90% of the entire shell. There are both large and small slabs.



tectonic plates photos


The biggest tectonic plates Pacific, Eurasian, African, Antarctic are considered. The lithosphere under oceans and continents is different. In particular, under the former the shell consists of oceanic crust, where there is almost no granite. In the second case, the lithosphere consists of sedimentary rocks, basalt and granite.

Lithosphere boundaries

The features of the lithosphere have different outlines. The lower boundaries are blurred, which is associated with a viscous medium, high heat conductivity and the speed of seismic waves. The upper boundary is the crust and mantle, which is quite thick and can only change due to the plasticity of the rock.

Functions of the lithosphere

The solid shell of the earth's surface has geological and ecological functions, which determine the course of life on the planet. It involves underground waters, oil, gases, fields of geophysical significance, processes, and the participation of various communities.

Among the most important functions are:

• Resource;
• Geodynamic;
• Geochemical;
• Geophysical.

Functions are manifested under the influence of natural and man-made factors, which is associated with the development of the planet, human activities and the formation of various ecological systems.

• The lithosphere arose in the process of gradually releasing substances from the Earth's mantle. Similar phenomena are still sometimes observed on the ocean floor, resulting in the appearance of gases and some water.
• The thickness of the lithosphere varies depending on climate and natural conditions. So, in cold regions, it reaches maximum value, and in warm weather it remains at minimum levels. The uppermost layer of the lithosphere is elastic, while the lower layer is very plastic. The solid shell of the Earth is constantly under the influence of water and air, which causes weathering. It happens physically when the rock disintegrates, but its composition does not change; as well as chemical - new substances appear.
• Due to the fact that the lithosphere is constantly moving, the appearance of the planet, its relief, the structure of plains, mountains, and lowlands change. Man constantly influences the lithosphere, and this participation is not always useful, resulting in serious contamination of the shell. First of all, this is due to the accumulation of garbage, the use of poisons and fertilizers, which changes the composition of soil, soil, and living beings.