What is the lithosphere. Question about ecology

The state of rest is unknown to our planet. This applies not only to external, but also to internal processes that occur in the bowels of the Earth: its lithospheric plates are constantly moving. True, some parts of the lithosphere are quite stable, while others, especially those located at the junctions tectonic plates, are extremely mobile and constantly shudder.

Naturally, similar phenomenon people could not leave it unattended, and therefore throughout their history they studied and explained it. For example, in Myanmar, the legend is still preserved that our planet is entwined with a huge ring of snakes, and when they begin to move, the earth begins to tremble. Similar stories could not satisfy inquisitive human minds for a long time, and in order to find out the truth, the most curious drilled the earth, drew maps, made hypotheses and put forward assumptions.

The concept of the lithosphere contains the solid shell of the Earth, consisting of the earth's crust and a layer of softened rocks, which are part of the upper mantle, the asthenosphere (its plastic composition makes it possible for the plates that make up the earth's crust to move along it at a speed of 2 to 16 cm per year). It is interesting that the upper layer of the lithosphere is elastic, and the lower layer is plastic, which makes it possible for the plates to maintain balance when moving, despite constant shaking.

During numerous studies, scientists came to the conclusion that the lithosphere has a heterogeneous thickness, and largely depends on the terrain under which it is located. So, on land, its thickness ranges from 25 to 200 km (the older the platform, the larger it is, and the thinnest is under the young mountain ranges).

But the thinnest layer of the earth's crust is under the oceans: its average thickness ranges from 7 to 10 km, and in certain regions Pacific Ocean even up to five. The thickest layer of the crust is located along the edges of the oceans, the thinnest - under the mid-ocean ridges. Interestingly, the lithosphere has not yet fully formed, and this process continues to this day (mainly under the ocean floor).

What is the earth's crust made of

The structure of the lithosphere under the oceans and continents is different in that there is no granite layer under the ocean floor, since the oceanic crust has undergone melting processes many times during its formation. common to oceanic and continental crust are such layers of the lithosphere as basalt and sedimentary.

Thus, the earth's crust consists mainly of rocks that are formed during the cooling and crystallization of magma, which penetrates into the lithosphere through cracks. If at the same time the magma could not seep to the surface, then it formed such coarse-grained rocks as granite, gabbro, diorite, due to its slow cooling and crystallization.

But the magma that managed to get out, due to rapid cooling, formed small crystals - basalt, liparite, andesite.

Concerning sedimentary rocks, then they were formed in the Earth's lithosphere in different ways: clastic ones appeared as a result of the destruction of sand, sandstones and clay, chemical ones formed due to various chemical reactions V aqueous solutions- this is gypsum, salt, phosphorites. Organic were formed by plant and lime residues - chalk, peat, limestone, coal.

Interestingly, some rocks appeared due to a complete or partial change in their composition: granite was transformed into gneiss, sandstone into quartzite, limestone into marble. According to scientific research, scientists managed to establish that the lithosphere consists of:

Oxygen - 49%;
Silicon - 26%;
Aluminum - 7%;
Iron - 5%;
Calcium - 4%
The composition of the lithosphere includes many minerals, the most common are feldspar and quartz.

As for the structure of the lithosphere, stable and mobile zones are distinguished here (in other words, platforms and folded belts). On tectonic maps, you can always see the marked boundaries of both stable and dangerous territories. First of all, this is the Pacific Ring of Fire (located along the edges of the Pacific Ocean), as well as part of the Alpine-Himalayan seismic belt ( Southern Europe and the Caucasus).

Description of platforms

A platform is a practically immovable part of the earth's crust that has gone through a very long stage geological formation. Their age is determined by the stage of formation of the crystalline basement (granite and basalt layers). Ancient or precambrian platforms on the map they are always located in the center of the continent, young ones are either on the edge of the mainland, or between the Precambrian platforms.

Mountain-fold area

The mountain-folded region was formed during the collision of tectonic plates, which are located on the mainland. If the mountain ranges were formed recently, increased seismic activity is recorded near them and they are all located at the edges lithospheric plates(younger massifs belong to the Alpine and Cimmerian stages of formation). Older areas related to ancient, Paleozoic folding, can be located both on the edge of the mainland, for example, in North America and Australia, and in the center - in Eurasia.

It is interesting that scientists determine the age of mountain-folded areas according to the youngest folds. Since mountain building is ongoing, this makes it possible to determine only the time frame of the stages of development of our Earth. For example, the presence of a mountain range in the middle of a tectonic plate indicates that the border once passed here.

Lithospheric plates

Despite the fact that the lithosphere is ninety percent composed of fourteen lithospheric plates, many do not agree with this statement and draw their own tectonic maps, saying that there are seven large and about ten small ones. This division is rather arbitrary, because with the development of science, scientists either identify new plates, or recognize certain boundaries as non-existent, especially when it comes to small plates.

It is worth noting that the largest tectonic plates are very clearly visible on the map and they are:

The Pacific is the largest plate on the planet, along the boundaries of which constant collisions of tectonic plates occur and faults form - this is the reason for its constant decrease;
Eurasian - covers almost the entire territory of Eurasia (except Hindustan and the Arabian Peninsula) and contains the most most continental crust;
Indo-Australian - consists of the Australian continent and the Indian subcontinent. Due to constant collisions with the Eurasian plate, it is in the process of breaking;
South American - consists of the South American mainland and part of the Atlantic Ocean;
North American - consists of the North American continent, part northeastern Siberia, the northwestern part of the Atlantic and half of the Arctic Oceans;
African - consists of the African continent and oceanic crust Atlantic and Indian Oceans. It is interesting that the plates adjacent to it move in the opposite direction from it, therefore the largest fault of our planet is located here;
The Antarctic Plate is made up of the mainland Antarctica and the nearby oceanic crust. Due to the fact that the plate is surrounded by mid-ocean ridges, the rest of the continents are constantly moving away from it.

Movement of tectonic plates

Lithospheric plates, connecting and separating, change their outlines all the time. This allows scientists to put forward the theory that about 200 million years ago the lithosphere had only Pangea - a single continent, which subsequently split into parts, which began to gradually move away from each other at a very low speed (an average of about seven centimeters per year ).

There is an assumption that due to the movement of the lithosphere, in 250 million years a new continent will form on our planet due to the union of moving continents.

When there is a collision of the oceanic and continental plates, the edge of the oceanic crust sinks under the continental one, while on the other side of the oceanic plate its boundary diverges from the plate adjacent to it. The boundary along which the movement of the lithospheres occurs is called the subduction zone, where the upper and plunging edges of the plate are distinguished. It is interesting that the plate, plunging into the mantle, begins to melt when the upper part of the earth's crust is squeezed, as a result of which mountains are formed, and if magma also breaks out, then volcanoes.

In places where tectonic plates are in contact with each other, there are zones of maximum volcanic and seismic activity: during the movement and collision of the lithosphere, the earth's crust collapses, and when they diverge, faults and depressions form (the lithosphere and the Earth's relief are connected with each other). This is the reason that along the edges of tectonic plates are located the most large forms relief of the Earth - mountain ranges with active volcanoes and deep-sea trenches.

Relief

It is not surprising that the movement of the lithosphere directly affects appearance of our planet, and the diversity of the Earth's relief is amazing (relief is a set of irregularities on earth's surface, which are above sea level at different heights, and therefore the main forms of the Earth's relief are conventionally divided into convex (continents, mountains) and concave - oceans, river valleys, gorges).

It is worth noting that the land occupies only 29% of our planet (149 million km2), and the lithosphere and the Earth's topography consist mainly of plains, mountains and low mountains. As for the ocean, its average depth is a little less than four kilometers, and the lithosphere and the relief of the Earth in the ocean consist of offshore, coastal slope, ocean floor and abyssal or deep sea trenches. Most of the ocean has a complex and varied relief: there are plains, basins, plateaus, hills, and ridges up to 2 km high.

Problems of the lithosphere

The intensive development of industry has led to the fact that man and the lithosphere in Lately began to get along extremely badly with each other: pollution of the lithosphere is acquiring catastrophic proportions. This happened due to the increase in industrial waste in conjunction with household waste and used in agriculture fertilizers and pesticides, which negatively affects chemical composition soil and living organisms. Scientists have calculated that about one ton of garbage falls per person per year, including 50 kg of hardly decomposable waste.

Today pollution of the lithosphere has become topical issue, since nature is not able to cope with it on its own: the self-purification of the earth's crust is very slow, and therefore harmful substances gradually accumulate and over time have a negative impact on the main culprit of the problem that has arisen - a person.

It is carried out by reducing the viscosity of rocks, increasing their electrical conductivity, and also due to the speed with which seismic waves propagate. The lithosphere has a different thickness on land and under the oceans. Its average value is 25-200 km for land and 5-100 km for.

95% of the lithosphere consists of igneous rocks of magma. Granites and granitoids are the predominant rocks on the continents, while basalts are such a rock.

The lithosphere is the medium for all known mineral resources, it is also an object human activity. Changes in the lithosphere affect the ecological.

Soils are one of the components of the upper parts of the earth's crust. For a person, they are of great importance. They are an organo-mineral product, which is the result of thousands of years of activity of various organisms, as well as factors such as air, water, solar light and warm. The thickness of the soil, especially in comparison with the thickness of the lithosphere itself, is relatively small. IN different regions it ranges from 15-20 cm to 2-3 m.

Soils appeared together with the emergence of living matter. Further they developed, they were influenced by the activity of microorganisms, plants and animals. The main number of all microorganisms and organisms that exist in the lithosphere is concentrated precisely in soils at a depth of several meters.

The lithosphere is called the outer shell of the Earth from a relatively solid material: this is the earth's crust and the upper layer of the mantle. The term "" was introduced by the American scientist Burrell in 1916, but at that time this concept meant only solid rocks that make up the earth's crust - the mantle was no longer considered part of this shell. Later, the upper parts of this layer of the planet (up to several tens of kilometers wide) were included in: they border on the so-called asthenosphere, which is characterized by low viscosity, high temperature at which the substances begin to melt.

The thickness is different in different parts Earth: under its layer can be from five kilometers in thickness - under the very deep places, and near the coast it already rises to 100 kilometers. Beneath the continents, the lithosphere extends up to two hundred kilometers in depth.

In the past, it was believed that the lithosphere has a monolithic structure and is not broken into parts. But this assumption has long been refuted - this one consists of several plates that move along the plastic mantle and interact with each other.

Hydrosphere

As the name implies, the hydrosphere is the shell of the Earth, consisting of water, or rather, these are all the waters on the surface of our planet and under the Earth: oceans, seas, rivers and lakes, as well as The groundwater. Ice and water in gaseous state or steam are also part water shell. The hydrosphere consists of more than one and a half billion cubic kilometers of water.

Water covers 70% of the Earth's surface, most of it falls on the World Ocean - almost 98%. Only one and a half percent is allocated to ice at the poles, and the rest is rivers, lakes, reservoirs, groundwater. Fresh water makes up only 0.3% of the entire hydrosphere.

The hydrosphere owes its appearance

The lithosphere of the planet Earth is a solid shell the globe, which includes multilayer blocks called lithospheric plates. As Wikipedia points out, translated from Greek This " 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 on internal arrangement 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 are in contact with each other. The structure itself consists of the following elements:

Asthenosphere. A layer with reduced hardness, which is located in the upper part of the planet in relation to the atmosphere. In some places it has very low strength, is prone to fracture and viscosity, especially if groundwater flows inside the asthenosphere.
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.
Core. The center of the globe, which has a liquid etiology, and from the movement of its mineral components and molecular structure molten metals depends on the preservation of the magnetic polarity of the planet and its rotation around its axis. Main component earth's core It is an alloy of iron and nickel.

What is the lithosphere? In fact, this is a solid shell of the Earth, which acts as an intermediate layer between fertile soil, mineral deposits, ores and 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 Caucasian mountains, the depth of this layer reaches 90 km.

Earth structure

Layers of the lithosphere

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

Sedimentary. Covers most of the top layer of all earth blocks. It mainly consists of volcanic rocks, as well as remnants organic matter, which over many millennia decomposed into humus. Fertile soils are also part of the sedimentary layer.
Granite. These are lithospheric plates located in in constant motion. They mainly consist of heavy-duty granite and gneiss. The last component is a metamorphic rock, the vast majority of which is filled with minerals from among potassium spar, quartz and plagioclase. The seismic activity of this layer of the hard shell is at the level of 6.4 km/sec.
Basaltic. Mostly composed of basalt deposits. This part of the solid shell of the Earth was formed under the influence of volcanic activity even 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 foregoing, we can conclude that this is a solid part of the globe, which has a heterogeneous composition. Its formation took place over several millennia, and its qualitative 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 the lithospheric plates, their seismic activity in relation to the structure of the Earth.

Layers of the lithosphere

oceanic lithosphere

This variety earth's shell significantly different from its mainland. This is due to the fact that the boundaries of the lithospheric blocks and the hydrosphere are closely intertwined, and in some of its parts body of water 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-type plates have their own structure and consist of the following layers:

marine sediments that have a total thickness of at least 1 km (may be completely absent in deep ocean areas);
secondary layer (responsible for the distribution of medium and longitudinal waves, moving at speeds up to 6 km / s., takes Active participation in the movement of plates, which provokes earthquakes of various power);
the lower layer of the solid shell of the globe in the region of the ocean floor, which is mainly composed of gabbro and borders on the mantle (the average activity of seismic waves is from 6 to 7 km/sec.).

A transitional type of lithosphere is also distinguished, located in the region of oceanic soil. It is characteristic of insular zones formed in an arcuate manner. In most cases, their appearance is associated with geological process movements of lithospheric plates, which were layered on top of each other, forming such 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

In terms of filling with organic and mineral compounds, the lithosphere does not differ in diversity and is mainly represented in the form of 8 elements.

For the most part, these are rocks that were formed during the period of active eruption of volcanic magma and the movement of plates. The chemical composition of the lithosphere is as follows:

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

Useful video: lithosphere and lithospheric plates

Conclusion

the rest chemical compounds, filling the lithospheric blocks are carbon, potassium, aluminum, titanium, sodium and silicon. In some regions of the planet, their concentration is greater, while in other parts of the solid shell of the Earth they are represented in a minimal amount.

Plains, lowlands, mountains, ravines - we all walk the earth, but we rarely think about the name of the upper shell of our planet with all its reliefs and landscapes. And her name is the lithosphere.

It includes not only the earth's crust, visible to the eye, but also a whole layer of solid earth rocks, as well as the upper part of the mantle, which has not yet been reached by deep drilling.

What does the word "lithosphere" mean?

Toponym for the first time "lithosphere" appeared in the dictionary of the ancient Greeks, combining two words together: λίθος , which means "stone", And φαίρα , translated as "sphere" or "ball". Close study of this concept began only in 1911, when the scientist A. E. Love published the monograph “Some Problems of Geodynamics”.

His idea was picked up in 1940 by the Harvard geologist Reginald Daly, who wrote the seminal work The Strength and Structure of the Earth. This work was accepted by many geologists and geophysicists, and by 1960 the so-called theory of tectonic plates was formed, which confirmed the existence of the lithosphere.

What is the thickness of the lithosphere?

Under the continents and oceans, the lithosphere has a different composition. Under the sea surface over millions of years of its history, it has gone through a number of stages of partial melting, so now it has a thickness of about 5–10 km and includes mainly harzburgites and dunites. At the same time, the granite layer is completely absent in its composition. Under the continents are several solid layers, the thickness of which is usually determined from the speed of seismic waves.

On the plains, the layer of the lithosphere reaches about 35 km, in the mountains it is somewhat larger - up to 70 km, and in the Himalayas the height of the upper layer of the Earth is over 90 km.

How many layers are in the lithosphere?

The lithosphere covers the entire surface of the globe, but, despite the large weight of the solid shell, it has a mass of only about 1% of total mass our planet.

According to studies, the lithosphere under the continents consists of three layers, differing in the way of formation and the type of rocks. Most of them are present crystalline substances, formed as a result of magma cooling - as it cools, hot solutions release minerals that either remain in their original form, or decompose under pressure and temperature and form new substances.

Upper sedimentary layer, which is loose continental deposits, appeared due to the chemical destruction of the rock, weathering and washing out by water. Over time, soil formed on it, which has a major impact on the interaction of living organisms and the earth's crust. Compared with the total thickness of the lithosphere, the thickness of the soil is relatively small - in different places it ranges from 20–30 cm to 2–3 meters.

As mentioned above, an intermediate granite layer exists only under the continents. It is composed mainly of igneous and metamorphic rocks that appeared after the crystallization of basaltic magma. These are, first of all, feldspars, the amount of which reaches 65% of the total mass of granite, as well as quartz and various dark-colored minerals - biotite, muscovite. The largest volumes of the granite layer are present at the joints continental plates where their depth is from 10 to 20 km.

The lower basalt layer is characterized by a high content of gabbro, iron, and non-ferrous igneous rocks. Their main mass forms the oceanic crust and is concentrated mainly in mountain ranges at the bottom of the ocean. However, large deposits of basalt can be found on the continents. In particular, in the CIS they occupy more than 44% of the entire territory.

Where seismic wave velocities decrease, indicating a change in rock plasticity. In the structure of the lithosphere, mobile areas (folded belts) and relatively stable platforms are distinguished.

The lithosphere under oceans and continents varies considerably. The lithosphere under the continents consists of sedimentary, granite and basalt layers with a total thickness of up to 80 km. The lithosphere under the oceans has undergone many stages of partial melting as a result of the formation of oceanic crust, it is highly depleted in low-melting rare elements, mainly consists of dunites and harzburgites, its thickness is 5-10 km, and the granite layer is completely absent.

The now obsolete term was used to designate the outer shell of the lithosphere sial, derived from the name of the basic elements of rocks Si(lat. Silicium- silicon) and Al(lat. Aluminum- aluminum).

Notes

Shells of the Earth
External
Internal

Wikimedia Foundation. 2010 .

Synonyms:

See what "Lithosphere" is in other dictionaries:

Lithosphere ... Spelling Dictionary

- (from litho ... and Greek sphaira ball) the upper solid shell of the Earth, bounded from above by the atmosphere and hydrosphere, and from below by the asthenosphere. The thickness of the lithosphere varies within 50,200 km. Until the 60s. the lithosphere was understood as a synonym for the earth's crust. Lithosphere ... Ecological dictionary

- [σφαιρα (ρsphere) sphere] the upper solid shell of the Earth, which has great strength and passes without a definite sharp boundary into the underlying asthenosphere, the strength of which is relatively low. L. in ... ... Geological Encyclopedia

LITHOSPHERE, the upper layer of the solid surface of the Earth, which includes the CRUST and the outermost layer of the MANTLE. The lithosphere can be of different thickness from 60 to 200 km in depth. Rigid, hard and brittle, it consists of a large number tectonic plates,… … Scientific and technical encyclopedic Dictionary

- (from litho ... and sphere), the outer shell of the solid Earth, including the earth's crust and part of the upper mantle. The thickness of the lithosphere under the continents is 25,200 km, under the oceans 5,100 km. Formed mainly in the Precambrian ... Modern Encyclopedia

- (from litho ... and sphere) the outer sphere of the solid Earth, including the earth's crust and upper part underlying its upper mantle ... Big Encyclopedic Dictionary

Same as the earth's crust... Geological terms

The hard shell of the earth. Samoilov K.I. Marine Dictionary. M. L.: State Naval Publishing House of the NKVMF USSR, 1941 ... Marine Dictionary

Exist., number of synonyms: 1 bark (29) ASIS synonym dictionary. V.N. Trishin. 2013 ... Synonym dictionary

The upper solid shell of the Earth (50 200 km), gradually becoming less strength and density of the rock substance with the depth of the sphere. L. includes the earth's crust (up to 75 km thick on the continents and 10 km under the ocean floor) and the Earth's upper mantle ... Emergencies Dictionary

Lithosphere- Lithosphere: the solid shell of the Earth, which includes the geosphere about 70 km thick in the form of layers of sedimentary rocks (granite and basalt) and the mantle up to 3000 km thick... Source: GOST R 14.01 2005. Environmental management. General provisions And… … Official terminology

Books

Earth is a restless planet. Atmosphere, hydrosphere, lithosphere. A book for schoolchildren... and not only, L. V. Tarasov. This popular educational book opens the world of natural spheres of the Earth to the inquisitive reader - the atmosphere, hydrosphere, lithosphere. The book describes in an interesting and intelligible way…