What is the lithosphere made of. What is the lithosphere and what does it consist of? What is the lithosphere from a scientific point of view

Consists of many layers piled on top of each other. However, we know best of all the earth's crust and lithosphere. This is not surprising - after all, we not only live on them, but also draw from the depths most of the available to us natural resources. But even the upper shells of the Earth preserve millions of years of the history of our planet and the entire solar system.

These two concepts occur so frequently in the press and literature that they have become everyday vocabulary modern man. Both words are used to refer to the surface of the Earth or another planet - however, there is a difference between the concepts based on two fundamental approaches: chemical and mechanical.

Chemical aspect - the earth's crust

If we divide the Earth into layers, guided by differences in chemical composition, the earth's crust will be the upper layer of the planet. This is a relatively thin shell, ending at a depth of 5 to 130 kilometers below sea level - the oceanic crust is thinner, and the continental, in mountainous areas, is the thickest. Although 75% of the mass of the crust falls only on silicon and oxygen (not pure, bound in the composition different substances), it is distinguished by the greatest chemical diversity among all layers of the Earth.

The richness of minerals also plays a role - various substances and blends created over billions of years of planetary history. The Earth's crust contains not only "native" minerals that were created by geological processes, but also a massive organic legacy, such as oil and coal, as well as alien inclusions.

Physical aspect - lithosphere

Relying on physical characteristics Earth, such as hardness or elasticity, we get a slightly different picture - the inside of the planet will wrap the lithosphere (from other Greek lithos, "rocky, hard" and "sphaira" sphere). She is much thicker earth's crust: the lithosphere extends up to 280 kilometers deep and even captures the upper solid part of the mantle!

The characteristics of this shell fully correspond to the name - it is the only solid layer of the Earth, except for the inner core. Strength, however, is relative - the Earth's lithosphere is one of the most mobile in solar system, because of which the planet has repeatedly changed its appearance. But for significant compression, curvature and other elastic changes, thousands of years are required, if not more.

An interesting fact is that a planet may not have a surface crust. Thus, the surface is its hardened mantle; The planet closest to the Sun lost its crust a long time ago as a result of numerous collisions.

To summarize, the earth's crust is the upper, chemically diverse part of the lithosphere, the solid shell of the earth. Initially, they had almost the same composition. But when only the underlying asthenosphere affected the depths and high temperatures, the hydrosphere, atmosphere, meteorite remnants and living organisms actively participated in the formation of minerals on the surface.

Lithospheric plates

Another feature that distinguishes the Earth from other planets is the diversity of diverse landscapes on it. Of course, its incredible big role water also played, which we will talk about a little later. But even the basic forms of the planetary landscape of our planet differ from the same Moon. The seas and mountains of our satellite are pits from meteorite bombardment. And on Earth they were formed as a result of hundreds and thousands of millions of years of movement lithospheric plates.

You have probably already heard about plates - these are huge stable fragments of the lithosphere that drift along the fluid asthenosphere, like broken ice on a river. However, there are two main differences between the lithosphere and ice:

The gaps between the plates are small, and are quickly tightened due to the molten substance erupting from them, and the plates themselves are not destroyed by collisions.
Unlike water, there is no constant flow in the mantle, which could set a constant direction for the movement of the continents.

So, driving force drift of lithospheric plates is the convection of the asthenosphere, the main part of the mantle - hotter flows from the earth's core rise to the surface, when cold ones sink back down. Considering that the continents differ in size, and the relief of their lower side mirrors the irregularities of the upper side, they also move unevenly and inconstantly.

Main plates

Over billions of years of movement of lithospheric plates, they repeatedly merged into supercontinents, after which they separated again. In the near future, in 200–300 million years, the formation of a supercontinent called Pangea Ultima is also expected. We recommend watching the video at the end of the article - it clearly shows how lithospheric plates have migrated over the past few hundred million years. In addition, the strength and activity of the movement of the continents determines the internal heating of the Earth - the higher it is, the more the planet expands, and the faster and freer the lithospheric plates move. However, since the beginning of the Earth's history, its temperature and radius have been gradually decreasing.

An interesting fact is that plate drift and geological activity need not be fueled by the internal self-heating of the planet. For example, Jupiter's moon has many active volcanoes. But the energy for this is provided not by the core of the satellite, but by gravitational friction with , due to which the bowels of Io are heated.

The boundaries of the lithospheric plates are very arbitrary - some parts of the lithosphere sink under others, and some, like the Pacific plate, are generally hidden under water. Geologists today have 8 main plates that cover 90 percent of the entire area of the Earth:

Australian
Antarctic
African
Eurasian
Hindustan
Pacific
North American
South American

Such a division appeared recently - for example, the Eurasian plate 350 million years ago consisted of separate parts, during the merger of which were formed Ural mountains, one of the most ancient on Earth. Scientists to this day continue to study the faults and the bottom of the oceans, discovering new plates and refining the boundaries of the old ones.

Geological activity

Lithospheric plates move very slowly - they crawl over each other at a speed of 1–6 cm/year, and move away as much as 10–18 cm/year. But it is the interaction between the continents that creates the geological activity of the Earth, tangible on the surface - volcanic eruptions, earthquakes and the formation of mountains always occur in the zones of contact of lithospheric plates.

However, there are exceptions - the so-called hot spots, which can exist in the depths of lithospheric plates. In them, molten flows of matter from the asthenosphere break upward, melting through the lithosphere, which leads to increased volcanic activity and regular earthquakes. Most often this happens near those places where one lithospheric plate creeps onto another - the lower, depressed part of the plate sinks into the Earth's mantle, thereby increasing the pressure of magma on the upper plate. However, now scientists are inclined to the version that the “drowned” parts of the lithosphere are melting, increasing pressure in the depths of the mantle and thereby creating updrafts. This can explain the anomalous remoteness of some hot spots from tectonic faults.

An interesting fact is that shield volcanoes often form in hot spots, characteristic of their flat shape. They erupt many times, growing due to flowing lava. It is also a typical format for alien volcanoes. The most famous of them on Mars, the most high point planets - its height reaches 27 kilometers!

Oceanic and continental crust of the Earth

Plate interaction also leads to the formation of two various types the earth's crust - oceanic and continental. Since the oceans, as a rule, are the junctions of various lithospheric plates, their crust is constantly changing - it is broken or absorbed by other plates. At the site of the faults, there is direct contact with the mantle, from which hot magma rises. Cooling under the influence of water, it creates a thin layer of basalts - the main volcanic rock. Thus, the oceanic crust is completely renewed every 100 million years - the oldest sections that are located in pacific ocean, reach a maximum age of 156–160 Ma.

Important! The oceanic crust is not all of the earth's crust that is under water, but only its young sections at the junction of the continents. Part continental crust located under water, in the zone of stable lithospheric plates.

Age oceanic crust(red corresponds to young bark, blue to old).

A lot of people different ages interested in what the lithosphere is. Alone now this topic take place at school, others - restore forgotten or lost during study. Let's just say. The lithosphere is hard shell Earth. Wikipedia says that it consists of the earth's crust and the upper part of the mantle, all the way down to the asthenosphere. Well, now in more detail.

Parts of the Earth that are interconnected and form single system are called shells. There are three main shells, but they are still divided into several types. But it is most convenient to first divide the Earth into a core, a mantle and a crust. And the lithosphere is the entire earth's crust with part of the mantle. It occupies only one percent of the entire mass of the planet on which we live.

The layer we are considering consists of three layers. However, its composition is still the subject of controversy. Anyway building material are hard rocks that become ductile as they approach the mantle.

The structure of the lithosphere

It consists of three layers:

The main component of the earth's crust is plates that are constantly moving, as if floating on the surface of the asthenosphere.

The composition differs depending on where it is located - under the oceans or continents. The three layers described above are characteristic of the continental structure. Thus, in the oceanic part there is no granite layer, and there are also significantly fewer low-melting rare compounds.

Folded belts and platforms can also be distinguished in the structure. The first sections are quite mobile, and the second ones are stable.

Question about ecology

The lithosphere is the only layer of the Earth available to us, and we use it very actively. It contains all the breeds of interest to us, mineral resources. Human intervention leads to environmental issues, such as a decrease in soil fertility, erosion, collapses within the boundaries of the lithosphere. Moreover, such interventions lead not only to local difficulties, but also global cataclysms.

The boundaries of the lithosphere

It is difficult to accurately determine the boundaries of the lithosphere. You can determine its end as you move deeper in by how quickly they move seismic waves. Scientists also use such signs as a decrease in the viscosity of the medium and an increase in thermal conductivity. Usually, the distance from the earth's crust to the beginning of the asthenosphere is several tens of kilometers.

The thickness differs depending on the place where its dimensions are measured:

The lithosphere has the greatest thickness in cold regions. It can also increase as density decreases. heat flow.

How was it formed?

The lithosphere appeared due to substances released from the upper layer of the Earth's mantle. The formation of the lithosphere is a continuous process, and continues to this day. In the process of its appearance, gases and small amounts of water are released.

Highly important role played igneous crystalline substances who formed the most most lithosphere. In turn, they appeared thanks to magma that came out through volcanoes to the surface of the Earth and cooled down.

Most huge contribution in the study of the lithosphere was carried out by seismology. This is the science that studies earthquakes. After all main reason why this phenomenon occurs, which sometimes has terrifying consequences - a collision tectonic plates between themselves. And in order to understand the cause of the earthquake, it was necessary to detect them.
Before the lithospheric plates were discovered and understood real reasons earthquakes, people used to come up with many versions that are now striking in their absurdity, but were taken quite seriously before. For example, earlier people it was believed that earthquakes appeared due to the fact that the snakes that entangled the earth were moving. It was only later that scientists proved that these “snakes” are the mantle, which in itself is quite mobile and plastic.
The composition includes the upper part of the mantle, because it is as hard as the Earth's crust, but it has a different chemical composition.
The word "lithosphere" is translated as " stone ball».
The temperature differs depending on the depth. Each kilometer deep adds 35 degrees to the temperature.

And, finally, the lower boundary of the lithosphere has a temperature of 1300 degrees.

Properties of the lithosphere

A more common name for the properties of the lithosphere is functions. Can be distinguished following features this layer of the planet Earth:

findings

We understood what the lithosphere is, figured out interesting facts about this layer of our planet. We figured out what its structure is, what it includes. We realized that the temperature of the lithosphere differs depending on the depth and much more. I hope you find this article useful. Good luck.

Lithosphere- the outer solid shell of the Earth, which includes the entire earth's crust with part of the upper mantle of the Earth and consists of sedimentary, igneous and metamorphic rocks. The lower boundary of the lithosphere is fuzzy and is determined by a sharp decrease in rock viscosity, a change in the propagation velocity of seismic waves, and an increase in the electrical conductivity of rocks. The thickness of the lithosphere on the continents and under the oceans varies and averages 25-200 and 5-100 km, respectively.
Consider in general view geological structure Earth. The third planet farthest from the Sun - the Earth has a radius of 6370 km, an average density of 5.5 g / cm3 and consists of three shells - the crust, mantle and core. The mantle and core are divided into inner and outer parts.

The earth's crust is thin upper shell The Earth, which has a thickness on the continents of 40-80 km, under the oceans - 5-10 km and is only about 1% of the mass of the Earth. Eight elements - oxygen, silicon, hydrogen, aluminum, iron, magnesium, calcium, sodium - form 99.5% of the earth's crust. On the continents, the crust is three-layered: siege

solid rocks cover granite ones, and granite ones overlie basalt ones. Under the oceans, the crust is of an "oceanic", two-layer type; sedimentary rocks lie simply on basalts, there is no granite layer. There is also a transitional type of the earth's crust (island-arc zones on the margins of the oceans and some areas on the continents, such as the Black Sea). The Earth's crust is thickest in mountainous areas(under the Himalayas - over 75 km), the middle one - in the areas of the platforms (under the West Siberian lowland - 35-40, within the boundaries of the Russian platform - 30-35), and the smallest - in central regions oceans (5-7 km). Dominant part earth's surface- these are the plains of the continents and the ocean floor. The continents are surrounded by a shelf - a shallow-water strip up to 200 g deep and an average width of about 80 km, which, after a sharp steep bend of the bottom, passes into the continental slope (the slope varies from 15-17 to 20-30 °). The slopes gradually level off and turn into abyssal plains (depths 3.7-6.0 km). The greatest depths (9-11 km) have oceanic trenches, the vast majority of which are located on the northern and western outskirts Pacific Ocean.

The main part of the lithosphere consists of igneous igneous rocks (95%), among which granites and granitoids predominate on the continents, and basalts in the oceans.

The relevance of the ecological study of the lithosphere due to the fact that the lithosphere is the environment of all mineral resources, one of the main objects anthropogenic activities(composite natural environment), through significant changes in which the global ecological crisis. In the upper part of the continental crust, soils are developed, the importance of which for humans can hardly be overestimated. Soils are an organo-mineral product of a long-term (hundreds and thousands of years) general activities living organisms, water, air, solar heat and light are among the most important natural resources. Depending on climatic and geological and geographical conditions, soils have a thickness of 15-25 cm to 2-3 m.

Soils arose together with living matter and developed under the influence of the activities of plants, animals and microorganisms until they became a very valuable fertile substrate for humans. The bulk of organisms and microorganisms of the lithosphere is concentrated in soils, at a depth of no more than a few meters. Modern soils are three-phase system(different-grained particulate matter, water and gases dissolved in water and pores), which consists of a mixture of mineral particles (destruction products rocks), organic matter(waste products of the biota of its microorganisms and fungi). The soils are playing huge role in the circulation of water, substances and carbon dioxide.

With different breeds the earth's crust, as well as from its tectonic structures associated with various minerals: combustible, metal, construction, as well as those that are raw materials for the chemical and food industries.

Within the boundaries of the lithosphere, terrible ecological processes(shifts, mudflows, landslides, erosion), which have great value to form environmental situations in a certain region of the planet, and sometimes lead to global environmental disasters.

The deep layers of the lithosphere, which are explored by geophysical methods, have a rather complex and still insufficiently studied structure, just like the mantle and core of the Earth. But it is already known that the density of rocks increases with depth, and if on the surface it averages 2.3-2.7 g/cm3, then at a depth of close to 400 km it is 3.5 g/cm3, and at a depth of 2900 km ( boundary of the mantle and the outer core) - 5.6 g/cm3. In the center of the core, where the pressure reaches 3.5 thousand tons/cm2, it increases to 13-17 g/cm3. The nature of the increase in the deep temperature of the Earth has also been established. At a depth of 100 km, it is approximately 1300 K, at a depth of close to 3000 km -4800, and in the center of the earth's core - 6900 K.

The predominant part of the Earth's matter is in a solid state, but on the border of the earth's crust and upper mantle (depths of 100-150 km) lies a stratum of softened, pasty rocks. This thickness (100-150 km) is called the asthenosphere. Geophysicists believe that other parts of the Earth may also be in a rarefied state (due to decompaction, active radio decay of rocks, etc.), in particular, the zone of the outer core. The inner core is in metal phase, but there is no consensus on its material composition today.

The lithosphere is the outer solid shell of the Earth, including the earth's crust and the upper part of the mantle. The lithosphere includes sedimentary, igneous and metamorphic rocks.

The lower boundary of the lithosphere is fuzzy and is determined by a decrease in the viscosity of the medium, the speed of seismic waves, and an increase in thermal conductivity. The lithosphere covers the earth's crust and the upper part of the mantle several tens of kilometers thick to the asthenosphere, in which the plasticity of rocks changes. The main methods for determining the boundary between the upper boundary of the lithosphere and the asthenosphere are magnetotelluric and seismological.

The thickness of the lithosphere under the oceans ranges from 5 to 100 km ( maximum value on the periphery of the oceans, the minimum - under the Mid-ocean ridges), under the continents - 25-200 km (maximum - under ancient platforms, minimum - under relatively young mountain ranges, volcanic arcs). The structure of the lithosphere under the oceans and continents has significant differences. Under the continents in the structure of the earth's crust of the lithosphere, sedimentary, granite and basalt layers are distinguished, the thickness of which as a whole reaches 80 km. Beneath the oceans, the Earth's crust has repeatedly undergone partial melting processes during the formation of the oceanic crust. Therefore, it is depleted in fusible rare compounds, lacks a granite layer, and its thickness is much less than that of the continental part of the earth's crust. The thickness of the asthenosphere (a layer of softened, pasty rocks) is about 100-150 km.

Formation of the atmosphere, hydrosphere and earth's crust

The formation occurred during the release of substances from the upper layer of the mantle of the young Earth. Currently, on the ocean floor in the middle ridges, the process of formation of the earth's crust continues, which is accompanied by the release of gases and small volumes of water. Oxygen is present in high concentrations in the composition of the modern earth's crust, followed by silicon and aluminum in percentage. Basically, the lithosphere is formed by compounds such as silicon dioxide, silicates, aluminosilicates. Crystalline substances took part in the formation of most of the lithosphere igneous origin. They were formed during the cooling of magma that came to the surface of the Earth, which is in the bowels of the planet in a molten state.

In cold regions, the thickness of the lithosphere is the greatest, and in warm regions it is the smallest. The thickness of the lithosphere can increase with a general decrease in the heat flux density. The upper layer of the lithosphere is elastic, and the lower layer is plastic in terms of the nature of the reaction to constantly acting loads. In tectonically active areas of the lithosphere, horizons of reduced viscosity are distinguished, where seismic waves travel at a lower speed. According to scientists, according to these horizons, some layers “slip” in relation to others. This phenomenon is called stratification of the lithosphere. In the structure of the lithosphere, mobile areas (folded belts) and relatively stable areas (platforms) are distinguished. Blocks of the lithosphere (lithospheric plates) move along the relatively plastic asthenosphere, reaching sizes from 1 to 10 thousand kilometers in diameter. At present, the lithosphere is divided into seven main and a number of small plates. The boundaries separating the plates from each other are the zones of maximum volcanic and seismic activity.

Earth's lithosphere in literal translation means "stone shell". This is one of the shells of the planet, formed by solid components. Consider what the lithosphere consists of and the proportion of which the planet needs it.

What it is?
What is the lithosphere formed by?
How do plates move?
Ecological situation
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What it is?

The planet's lithosphere is the layer covering it, formed by the upper part of the mantle and the earth's crust. Such a definition was given in 1916 by the scientist Burrell. It is located on a softer layer - the asthenosphere. The lithosphere covers the entire planet completely. Top thickness hard shell is not the same in different areas. On land, the thickness of the shell is 20-200 km, in the oceans - 10-100 km. An interesting fact is the presence of a Mohorović surface. This is a conditional boundary separating layers with different seismic activity. Here there is an increase in the density of the substance of the lithosphere. This surface completely repeats the earth's relief.

Rice. 1. The structure of the lithosphere

What is the lithosphere formed by?

The development of the lithosphere has been going on since the formation of the planet. Solid earthly shell formed mainly by igneous and sedimentary rocks. In the course of various studies, the approximate composition of the lithosphere was established:

oxygen;
silicon;
aluminum;
iron;
calcium;
trace elements.

The outer layer of the lithosphere is called the earth's crust. This is a relatively thin shell, having a thickness of no more than 80 km. The greatest thickness is noted in the mountainous regions, the smallest - in the plains. The composition of the earth's crust on the continents includes three layers - sedimentary, granite and basalt. In the oceans, the crust is formed by two layers - sedimentary and basalt, the granite layer is absent.

Many planets have crust, but only the Earth has differences between oceanic and continental crust.

Under the crust is the main part of the lithosphere. It consists of separate blocks - lithospheric plates. These plates slowly move along a softer shell - the asthenosphere. The processes of plate movement are studied by the science of tectonics.

How do plates move?

The regularities of the lithosphere also include features of the movement of lithospheric plates. They constantly change their outlines, but this happens so slowly that a person is not able to notice it. It is assumed that 200 million years ago there was only one continent on the planet - Pangea. Due to some internal processes there was a separation of it into separate continents, the boundaries of which pass through the places of the split of the earth's crust. A sign of plate movement today can serve as a gradual warming of the climate.

Since the movement of lithospheric plates does not stop, some scientists suggest that in a few million years the continents will again unite into one continent.

What kind natural phenomena associated with plate movement? In the places of their collision, the boundaries of seismic activity pass - when the plates hit each other, an earthquake begins, and if this happened in the ocean, then a tsunami.

The movements of the lithosphere are also responsible for the formation of the planet's topography. The collision of lithospheric plates leads to the crushing of the earth's crust, resulting in the formation of mountains. Underwater ridges appear in the ocean, and in places where plates diverge - deep sea trenches. The relief also changes under the influence of air and water shells planets - hydrospheres and atmospheres.

Rice. 3. Due to the movement of lithospheric plates, mountains are formed

Ecological situation

One example of the connection between the biosphere and the lithosphere is the active influence of human actions on the shell of the planet. The rapidly developing industry leads to the fact that the lithosphere is completely polluted. Chemical and radiation waste, pesticides, hardly decomposable garbage are buried in the soil. The influence of human activity has a noticeable effect on the relief.

What have we learned?

We learned what the lithosphere is and how it was formed. We found out that the lithosphere consists of several layers, and its thickness is not the same in different parts of the planet. The components of the lithosphere are various metals and trace elements. The movement of lithospheric plates causes earthquakes and tsunamis. On the state of the lithosphere big influence has an anthropogenic impact.

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