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, people could not leave such a phenomenon 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. Such 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 earth's crust and a layer of softened rocks that make up the upper mantle, the asthenosphere (its plastic composition enables 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 some regions of the Pacific Ocean it even reaches 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 the 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.

As for sedimentary rocks, they were formed in the Earth's lithosphere in different ways: detrital rocks appeared as a result of the destruction of sand, sandstones and clay, chemical ones were formed due to various chemical reactions in aqueous solutions it 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

The platform is practically immovable parts of the earth's crust that have gone through a very long stage of 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 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 the 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 ninety percent of the lithosphere consists 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 largest part of the 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 of northeastern Siberia, the northwestern part of the Atlantic and half of the Arctic Oceans;
• African - consists of the African mainland and the oceanic crust of the 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 enables 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 the oceanic and continental plates collide, 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 come into 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 to each other). This is the reason why the largest landforms of the Earth are located along the edges of the tectonic plates - 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 (the relief is a set of irregularities on the earth's surface, which are above sea level at different heights, and therefore the main forms of the Earth's relief are conditionally 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 a continental shelf, a coastal slope, an oceanic bed, 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 have recently become extremely difficult to get along with each other: pollution of the lithosphere is acquiring catastrophic proportions. This happened due to an increase in industrial waste in combination with household waste and fertilizers and pesticides used in agriculture, 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: self-purification of the earth's crust occurs very slowly, and therefore harmful substances gradually accumulate and over time negatively affect the main culprit of the problem that has arisen - man.

The lithosphere of the planet Earth is a solid shell of the globe, which includes multilayer blocks called lithospheric plates. As Wikipedia points out, translated from Greek it 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 on 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 are in contact with 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 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.
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, 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 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 remnants organic matter, which over many millennia decomposed into humus. Fertile soils are also part of the sedimentary layer.
2. Granite. These are lithospheric plates that are 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.
3. Basaltic. Mostly composed of basalt deposits. This part of the solid shell of the Earth was formed under the influence of volcanic activity 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 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 type of the earth's shell is 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 the water space extends beyond the surface layer of the 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 propagation of medium and longitudinal waves moving at speeds up to 6 km / s, takes an active part 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 the geological process of the movement 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:

1. 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.
2. Magnesium. This is 2.35% of the solid shell of the Earth. Its appearance in the lithosphere is associated with magmatic activity in the early periods of the formation of the planet. It is found throughout the continental, marine and oceanic parts of the planet.
3. 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 that the highest density of this 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.

Knowledge about the tectonic structure of the Earth is not yet deep enough, since it is built only on indirect evidence. Accurate data are available only on the upper layer of our planet, which does not exceed 1.5 dozen kilometers. If you think about it, we know much less about the internal structure of the Earth than about space, which is explored by satellites and spacecraft.
However, the study of the tectonic structure of the Earth is very important. It is associated with the features of the relief of the earth's surface, the appearance and location of all types of minerals, the formation of volcanoes and the occurrence of earthquakes. Knowledge of the tectonic structure of the Earth is also useful for obtaining information about possible geological and geographical changes.


The Earth is an oblate spheroid, which consists of the following layers:
1) Lithosphere
2) Mantle
3) Core


Let's look at each of these layers in more detail.
1. Lithosphere. Lithosphere in Greek means a stone ball. It is a spherical solid shell of the Earth. This layer is about 100 kilometers thick. Also included in the lithosphere is the asthenosphere, the so-called upper mantle, on which most of the lithosphere is located. The substance of which the asthenosphere consists is in a plastic state, that is, between a solid and a liquid body. As a result of this process, the lithosphere seems to be floating in the upper mantle.


The upper part of the lithosphere is the earth's crust. The outer boundary of the earth's crust is that part where the earth's surface is in contact with the atmosphere and hydrosphere. The lower part is located at a depth of 7 to 76 km.
The structure of the earth's crust has several layers. The thickness of the upper layer is in the range of 0–20 km. It consists of sedimentary rocks, such as sand, clay, limestone, etc. The results of seismic studies show that these rocks are loose, and the wave speed is very low.
Under the continents there is a granite layer, which consists of rocks, the density of which is equal to the density of granite. Seismic waves pass through this layer at a speed of 5 - 6 km/s.


There is no granite layer at the bottom of the oceans, but on the continents this layer can sometimes be seen on the surface.
Even lower is the basalt layer, in which seismic waves reach a speed of 6.5 km / s.
In the middle of the granite and basalt layer there is a boundary called the Conrad surface. Within this boundary, there is a jerk in the speed of the passage of seismic activity within 6–6.5 km/s.

Correspondingly, according to the thickness and structure, the crust is divided into two types: continental and oceanic. From the bottom of the continents, the crust includes the following layers: sedimentary, granite and basalt. Its thickness on the plains is 15 kilometers, and in the mountains it can increase to 80 kilometers, forming "mountain roots". At the bottom of the oceans, the granitic layer is in most cases completely absent, and the basalt layer is covered with a thin film of sedimentary rocks. In parts of the ocean with great depth, the thickness of the crust reaches 3–5 kilometers, and below is the upper mantle.


The relevance of the ecological study of the lithosphere is explained by the fact that it is in it that the source of all mineral resources. The lithosphere is also one of the most important objects of anthropogenic activity, as a result of significant changes in which a general ecological crisis. So, in the upper part of the earth's crust there are soils, the importance of which for mankind is difficult to overestimate. Soils are an organo-mineral product of long-term (hundreds and thousands of years) joint activities water, air, living organisms, solar heat and light are among the most important natural resources. Based on the climatic and geological and geographical conditions, the soils are from 15-25 centimeters to 2-3 meters thick.


2. The mantle is an intermediate shell that is located between the lithosphere and the core of the planet, which includes silicate rocks rich in iron and magnesium. The mantle is almost 2900 kilometers thick and makes up 83% of the volume and 67% of the mass of the Earth.




The temperature in the mantle, as is known, is no more than 2-2.5 thousand degrees. Its substance is in a hot state and feels very strong pressure from the lithosphere located above. The mantle has a great influence on the processes that occur on Earth. It is made up of several different layers. Magma chambers form in the upper layer of the mantle, resulting in ores, diamonds and other fossils. In the same way, heat is transferred to the Earth's surface. The upper mantle is constantly and actively moving, causing the movement of the lithosphere and the earth's crust.


3. The core is a layer rich in iron and nickel, which consists of two layers: inner and outer core. The outer core is liquid-like, because transverse waves do not pass through it and has a depth of up to 5 thousand km, the inner core consists of solid matter. Tension in the Earth's outer core magnetic field averages 25 Gauss, which is 50 times greater than on the surface. The material of the core, especially the inner one, is highly compacted and is equal in density to metals, which is why it is called metallic. Recent studies have proven that the Earth's inner core rotates slightly faster than the rest of the planet.

Almost nothing is known about the core, since all the data were obtained by indirect methods and research, and samples of the constituent substances of the core cannot be obtained, and are unlikely to be obtained in the near future.


And any negative lithospheric changes can exacerbate the global crisis. From this article you will learn about what the lithosphere and lithospheric plates are.

Concept definition

The lithosphere is the outer hard shell of the globe, which consists of the earth's crust, part of the upper mantle, sedimentary and igneous rocks. It is rather difficult to determine its lower boundary, but it is generally accepted that the lithosphere ends with a sharp decrease in the viscosity of rocks. The lithosphere occupies the entire surface of the planet. The thickness of its layer is not the same everywhere, it depends on the terrain: on the continents - 20-200 kilometers, and under the oceans - 10-100 km.

The Earth's lithosphere mostly consists of igneous igneous rocks (about 95%). These rocks are dominated by granitoids (on the continents) and basalts (under the oceans).

Some people think that the concepts "hydrosphere" / "lithosphere" mean the same thing. But this is far from true. The hydrosphere is a kind of water shell of the globe, and the lithosphere is solid.

Geological structure of the globe

The lithosphere as a concept also includes the geological structure of our planet, therefore, in order to understand what the lithosphere is, it should be considered in detail. The upper part of the geological layer is called the earth's crust, its thickness varies from 25 to 60 kilometers on the continents, and from 5 to 15 kilometers in the oceans. The lower layer is called the mantle, separated from the earth's crust by the Mohorovichich section (where the density of matter changes dramatically).

Earth consists of the earth's crust, mantle and core. The earth's crust is a solid, but its density changes dramatically at the boundary with the mantle, that is, at the Mohorovichic line. Therefore, the density of the earth's crust is an unstable value, but the average density of a given layer of the lithosphere can be calculated, it equals 5.5223 grams / cm 3.

The globe is a dipole, that is, a magnet. Earth's magnetic poles are located in the southern and northern hemispheres.



Layers of the Earth's lithosphere

The lithosphere on the continents consists of three layers. And the answer to the question of what the lithosphere is will not be complete without considering them.

The upper layer is built from a wide variety of sedimentary rocks. The middle one is conditionally called granite, but it consists not only of granites. For example, under the oceans, the granite layer of the lithosphere is completely absent. The approximate density of the middle layer is 2.5-2.7 grams/cm 3 .

The lower layer is also conditionally called basalt. It consists of heavier rocks, its density, respectively, is greater - 3.1-3.3 grams / cm 3. The lower basalt layer is located under the oceans and continents.

The earth's crust is also classified. There are continental, oceanic and intermediate (transitional) types of the earth's crust.



The structure of lithospheric plates

The lithosphere itself is not homogeneous, it consists of peculiar blocks, which are called lithospheric plates. They include both oceanic and continental crust. Although there is a case that can be considered an exception. The Pacific lithospheric plate consists only of oceanic crust. The lithospheric blocks consist of folded metamorphic and igneous rocks.

Each continent has at its base an ancient platform, the boundaries of which are defined by mountain ranges. Plains and only individual mountain ranges are located directly on the platform area.

Seismic and volcanic activity is quite often observed at the boundaries of lithospheric plates. There are three types of lithospheric boundaries: transform, convergent, and divergent. The outlines and boundaries of lithospheric plates change quite often. Small lithospheric plates are connected to each other, while large ones, on the contrary, break apart.



List of lithospheric plates

It is customary to distinguish 13 main lithospheric plates:

• Philippine plate.
• Australian.
• Eurasian.
• Somali.
• South American.
• Hindustan.
• African.
• Antarctic Plate.
• Nazca plate.
• Pacific;
• North American.
• Scotia plate.
• Arabian plate.
• Cooker Coconut.

So, we gave a definition of the concept of "lithosphere", considered the geological structure of the Earth and lithospheric plates. With the help of this information, it is now possible to answer with certainty the question of what the lithosphere is.

Line UMK O. A. Klimanova, A. I. Alekseev. Geography (5-9)

Geography

Earth's lithosphere

More than 4 billion years ago, from cosmic dust flying in interstellar space after, under the influence of gravity, a beautiful blue planet Earth. It is the third planet from the Sun solar system, and the only one on which life is known to mankind.

Glossary

Asthenosphere- located at a depth of about 150-200 km, a partially melted, viscous layer.

Lava magma that is devoid of gases and solidified on the Earth's surface.

Magma- fiery mass in the asthenosphere layer, molten, containing a large amount of gases.

Lithospheric plates- giant sections of the earth's crust, freely moving through the viscous layer of the mantle.

Areas of folding- sections of the earth's crust between the plates of the lithosphere, which are in relative motion, in the relief they correspond to the mountain systems of the land and the bottom of the seas.

Definition of the lithosphere

Lithosphere(λίθος - "stone" and σφαίρα - "ball") is called a solid earthly shell that completely covers the planet, protecting it from the temperature of the hot core reaching 60,000 ° C. The lithosphere is located between atmosphere and hydrosphere top and asthenosphere from below. The thickness of the hard shell of the Earth is not uniform, and in different areas it ranges from tens to several hundreds of kilometers.

Pangea

Despite its considerable age, the formation of the planet has not yet been completed. And the thin surface of the crust, which is home to humans, plants and animals, and the hot bowels are in constant motion. The outlines of the continents, the terrain, and climatic conditions are changing.

Looking at modern satellite images of the planet with the outline of six separate continents, it is hard to believe that about 250 million years ago there was a single supercontinent on the planet, called Pangea.

As a result of active processes in the bowels of the planet, a single continent split into modern continents, which, thanks to the slow, from 2.5 cm to 7 cm per year (according to various sources), the movement of tectonic plates over millions of years moved away by maximum distance. The proofs of this theory are detailed on page 178 of the textbook edited by O. A. Klimanova.

Climbing the scratching clouds of a mountain or descending into the depths of the ocean, a person considers himself a conqueror of nature, but not a single man-made skyscraper can be compared in height with the mountains, and not a single bathyscaphe has descended into the deepest Mariana Trench.

The surface of the lithosphere is not continuous, but is represented by separate plates, which in some places find each other, forming mountain ranges or diverge, forming sea depressions.

In the structure of the lithosphere, scientists distinguish eight large plates and a significant number of smaller ones. The plates are not fixed motionless, but slowly move along the hot and liquid asthenosphere, forming zones of seismic activity at the joints of the plates.



The textbook is addressed to students in grades 5-6 and is included in the line of geography textbooks edited by O.A. Klimanova and A.I. Alekseev. The methodological apparatus of the textbook is well developed and reflects the idea of ​​developmental and student-centered learning; the possibility of parallel work with the electronic supplement to the textbook contributes to the effective assimilation educational material. The textbook is especially suitable for grammar schools and classes with in-depth study of the humanities.

Major tectonic plates:

• australian plate
• Antarctic Plate
• African plate
• Eurasian plate
• Hindustan plate
• Pacific Plate
• North American Plate
• South American Plate

The structure of the lithosphere

If you look at the Earth in a cross section along the poles, then you can distinguish: the earth's crust, boundary layer, mantle, core.




The lithosphere includes: Earth's crust, transition layer and the topmost viscous mantle layer.

The lithosphere, which we are now talking about, is only about 1% of the radius of the earth, but it is this 1% that allows life to exist on the planet.

Earth's crust- the uppermost layer of the lithosphere. You can be convinced of the heterogeneity of the earth's crust by standing on the shore and looking at the cliff of a modest river, where layers of various rocks are located one above the other. Minerals found during excavations (oil, gas, iron ore, diamonds) tell scientists about the processes taking place on the planet millions of years ago.

The earth's crust is not only the uppermost layer of the lithosphere, but also the thinnest - its size ranges from 80 kilometers in the mountainous areas of the planet to 30 km in the plains. By type, the earth's crust is divided into oceanic and mainland. Such a division is typical only for the Earth, on the other planets there is no such division, according to the testimony of space probes and planetary rovers.

In the crust of the continental type, three layers of rocks are distinguished:

• sedimentary- formed by rocks of sedimentary and volcanic origin;
• granite- formed by rocks of metamorphic mountain origin, which are represented by quartz and feldspar;
• basaltic- igneous rocks participated in the formation.

The oceanic crust consists of sedimentary and basaltic layers.

Under the earth's crust, exactly repeating its shape, and separating it from the mantle, there is a boundary layer or surface of Mohorovichich. The Mohorovichic boundary is a thin layer of ash that is formed as a result of electrical discharge lightning flowing in the upper layer of the mantle.

The huge pressure between the mantle and the earth's crust has led to the fact that the ash layer is compressed and, when seismic waves are transmitted, behaves like a dense, almost monolithic substance. The surface of Mohorovichic performs hydro-, electrical and thermal insulation functions.

The mantle is divided into two layers:

• upper, which belongs to the lithosphere;
• lower, enveloping the red-hot core.

The core, liquid on the outside and dense inside, consists mainly of iron and nickel.

In the upper layer of the mantle, red-hot magma is formed, seeking its way out through faults in the earth's crust at the points of contact of tectonic plates. And it is in the depths that ordinary coal, under the influence of pressure and temperature, turns into the most durable (and also precious) stone - diamond.

Ways to study the earth's crust

How do scientists know this, you ask? After all, the thickness of the earth's crust is about 60-70 kilometers, and man-made drilling rigs have reached a depth of just over 12 kilometers.

One of the ways to study the earth's interior is described on page 86 of the textbook edited by Klimanova O.A.




Volcanoes are deadly, but at the same time impressive and bewitching evidence of the fiery processes taking place in the bowels of the earth. Having overcome the resistance of the earth's crust, hot magma is ejected to the surface under pressure, which, cooling in the atmosphere, turns into lava rivers carrying volcanic stones and gas, and with them information for scientists about the processes occurring deep inside the Earth.

Active active volcanoes are located along the lines of deep faults in the earth's crust. The Pacific Ring of Fire, which includes the volcanoes of Kamchatka, Japan, the Philippine Islands, Indonesia, Mexico, the Aleutian Islands, South America and Tierra del Fuego gives scientists answers to questions, and observers - an unforgettable sight.

But the “breathing” of the planet and its active life can be seen in less destructive examples.

Among the ancient city ruins of the small town of Pozzuoli, located on the shores of the Gulf of Naples, in the city center there are the remains of an ancient temple and the market square adjacent to it, built more than two thousand years ago, during the time of the Roman Empire. Even with the naked eye, it is noticeable that the marble columns are eaten away by sea stoners almost 6 meters in height.



It is known from historical chronicles that XIII century the town square sank below sea level. However, this did not happen all at once, as a result of an earthquake or other cataclysm, but slowly, year after year. For three centuries, the remains of the buildings were flooded, then the land slowly began to rise. By 1800, the ruins were again above sea level, and inquisitive tourists can observe with their own eyes the unique phenomenon of bradysames, when a layer of magma comes so close to the earth's crust that as a result of underground movements, the surface of the Earth rises and falls.

With the help of leading questions and visual material in the form of tables and diagrams, the children learn about the movement of lithospheric plates, indicating their boundaries on the map.

The guys schematically sketch the structure of the continental and oceanic crust.

Then samples of minerals of different origin are considered, differences between representatives of different lithospheric layers are determined.

The final stage is testing on the topic.

Topics of reports

• From Pangea to 6 continents. The movement of lithospheric plates
• Treasures of the bowels of the Earth
• Three lives of carbon: from graphite to diamond
• The richer, the more happy. Minerals of the native land

TEST

1. What is the name of the hard shell of the Earth?
   • lithosphere +
   • nanosphere
   • atmosphere
2. Pangea is...
   • name of the ancient Greek goddess of fertility
   • the name of a single continent that once existed on planet Earth +
   • name of a planet in the Crab Nebula
3. What is called the Pacific Ring of Fire?
   • oil tanker fires in the Pacific
   • active active volcanoes located along the lines of deep faults in the earth's crust +
   • a swarm of glowing plankton seen in the Pacific Ocean at night
4. What other phenomenon testifies to the “breathing” of the planet?
   • astronautics
   • tectonics
   • bradysames +
5. The Mohorovichic surface is located...
   • between the earth's crust and the upper layer of magma +
   • between basalt and sedimentary layers of the earth's crust
   • between the lower layer of magma and the earth's core
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