The rocky shell of the Earth - the earth's crust - is firmly attached to the upper mantle and forms a single whole with it - the lithosphere. The study of the earth's crust and lithosphere allows scientists to explain the processes occurring on the Earth's surface and anticipate changes in the appearance of our planet in the future.

Structure of the earth's crust

Earth's crust, consisting of igneous, metamorphic and sedimentary rocks, on continents and under oceans has different thickness and structure. It is customary to distinguish three layers in the continental crust. The upper layer is sedimentary, in which sedimentary rocks predominate. The two lower layers are conventionally called granite and basalt. The granite layer consists primarily of granite and metamorphic rocks. The basalt layer is made of denser rocks, comparable in density to basalts. Oceanic crust has two layers. In it upper layer– sedimentary – has a small thickness, the lower layer – basalt – consists of basalt rocks, and there is no granite layer.

The thickness of the continental crust under the plains is 30–50 kilometers, under the mountains – up to 75 kilometers. The oceanic crust is much thinner, its thickness is from 5 to 10 kilometers. There is a crust on other terrestrial planets, on the Moon and on many satellites of the giant planets of the Solar System. But only the Earth has two types of crust: continental and oceanic. On other planets, in most cases it consists of basalts.

Lithosphere

origin of name

The lithosphere is the solid shell of the Earth. It consists of the earth's crust, as well as the upper part of the mantle. The term “lithosphere” was proposed in 1916 by J. Burrell and until the 60s. twentieth century was synonymous with the earth's crust. Then it was proven that the lithosphere also includes the upper layers of the mantle up to several tens of kilometers thick. This concept itself comes from two Greek words, the first of which means “stone”, and the second means “ball” or “sphere”.

The lithosphere is the solid shell of the Earth, which includes the earth's crust and part of the upper mantle. The thickness of the lithosphere on land on average ranges from 35-40 km (in flat areas) to 70 km (in mountainous areas). Under the ancient mountains the thickness of the earth's crust is even greater: for example, under the Himalayas its thickness reaches 90 km. The Earth's crust under the oceans is also the lithosphere. Here it is the thinnest - on average about 7-10 km, and in some areas of the Pacific Ocean - up to 5 km.

General characteristics of the lithosphere

In the structure of the lithosphere, mobile regions (folded belts) and relatively stable platforms are distinguished.

The thickness of the lithosphere varies from 5 to 200 km. Under the continents, the thickness of the lithosphere varies from 25 km under young mountains, volcanic arcs and continental rift zones to 200 or more kilometers under the shields of ancient platforms. Under the oceans, the lithosphere is thinner and reaches a minimum of 5 km under the mid-ocean ridges; on the periphery of the ocean, gradually thickening, reaching a thickness of 100 km. The lithosphere reaches its greatest thickness in the least heated areas, and its least in the hottest ones.

According to the reaction to long-term effective loads in the lithosphere it is customary to distinguish the upper elastic and lower plastic layers. Also on different levels In tectonically active regions of the lithosphere, horizons of relatively low viscosity can be traced, which are characterized by low velocities of seismic waves. Geologists do not exclude the possibility of some layers slipping relative to others along these horizons. This phenomenon is called lithospheric layering.

The largest elements of the lithosphere are lithospheric plates with dimensions of 1–10 thousand km in diameter. Currently, the lithosphere is divided into seven main and several minor plates. The boundaries between plates are drawn along the zones of greatest seismic and volcanic activity.

Lithosphere boundaries

The upper part of the lithosphere borders the atmosphere and hydrosphere. The atmosphere, hydrosphere and upper layer of the lithosphere are in a strong relationship and partially penetrate each other.

The lower boundary of the lithosphere is located above the asthenosphere - a layer of reduced hardness, strength and viscosity in the upper mantle of the Earth. The boundary between the lithosphere and asthenosphere is not sharp - the transition of the lithosphere to the asthenosphere is characterized by a decrease in viscosity, a change in the speed of seismic waves and an increase in electrical conductivity. All these changes occur due to an increase in temperature and partial melting of the substance. Hence the main methods for determining the lower boundary of the lithosphere - seismological and magnetotelluric.

Lithospheric plates

Despite the fact that ninety percent of the lithosphere consists of fourteen lithospheric plates, many disagree with this statement and draw their own tectonic maps, saying that there are seven large and about ten small ones. This division is quite arbitrary, since 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 for Hindustan and the Arabian Peninsula) and contains the largest part of the continental crust;
• Indo-Australian - it includes 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 continent 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 continent and the oceanic crust of the Atlantic and Indian oceans. Interestingly, the plates adjacent to it move in the opposite direction from it, so the largest fault on our planet is located here;
• Antarctic plate – consists of the continent of Antarctica and nearby oceanic crust. Due to the fact that the plate is surrounded by mid-ocean ridges, the remaining continents are constantly moving away from it.

Geological activity

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

However, there are exceptions - so-called hot spots, which can also exist deep in lithospheric plates. In them, molten flows of asthenosphere matter break upward, melting 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 believe that the “drowned” parts of the lithosphere are melting, increasing pressure in the depths of the mantle and thereby creating upward flows. This can explain the anomalous distance of some hot spots from tectonic faults.

Interesting fact– shield volcanoes, characterized by their flat shape, often form in hot spots. They erupt many times, growing due to flowing lava. This is also a typical alien volcano format. The most famous of them is the Olympus volcano on Mars, the most high point planet – its height reaches 27 kilometers!

Lithosphere and crust of the Earth in astronomy

Studying the Earth rarely happens just like that - often the searches of scientists have a very clear practical goal. This is especially relevant in the study of the lithosphere: at the junctions of lithospheric plates, whole placers of ores and valuable minerals come out, for the extraction of which in another place it would be necessary to drill a many-kilometer well. Many data about the earth's crust were obtained thanks to the oil field - in the search for oil and gas deposits, scientists learned a lot about the internal mechanisms of our planet.

Therefore, it is not for nothing that astronomers strive for a detailed study of the crust of other planets - its outlines and appearance reveal everything internal organization space object. For example, on Mars, volcanoes are very high and erupt repeatedly, while on Earth they constantly migrate, appearing periodically in new places. This indicates that on Mars there is no such active movement of lithospheric plates as on Earth. Along with the absence magnetic field, the stability of the lithosphere became the main evidence of the stopping of the core of the red planet and the gradual cooling of its interior.

§ 13. The Earth's crust and lithosphere - the rocky shells of the Earth

Remember

• What inner shells of the Earth stand out? Which shell is the thinnest? Which shell is the largest? How are granite and basalt formed? What is their appearance?

The earth's crust and its structure. The Earth's crust is the outermost rocky shell of the Earth. It consists of igneous, metamorphic and sedimentary rocks. On continents and under oceans it is structured differently. Therefore, a distinction is made between the continental crust and the oceanic crust (Fig. 42). They differ from each other in thickness and structure. The continental crust is more powerful - 35-40 km, under high mountains- up to 75 km. It consists of three layers. The top layer is sedimentary. It is composed of sedimentary rocks. The second and third layers consist of a variety of igneous and metamorphic rocks. The second, middle layer is conventionally called “granite”, and the third, lower layer is called “basalt”.

Rice. 42. Structure of the continental and oceanic crust

The oceanic crust is much thinner - from 0.5 to 12 km - and consists of two layers. The upper, sedimentary layer is composed of sediments covering the bottom of modern seas and oceans. The bottom layer consists of solidified basaltic lavas and is called basalt.

Continental and oceanic crust on the surface of the Earth form giant steps of different heights. The higher levels are the continents rising above sea level, the lower ones are the bottom of the World Ocean.

Lithosphere. As you already know, under the earth's crust is the mantle. The rocks that make it up differ from the rocks of the earth's crust: they are denser and heavier. The earth's crust is firmly attached to the upper mantle, forming a single whole with it - the lithosphere (from the Greek "cast" - stone) (Fig. 43).

Rice. 43. Relationship between the lithosphere and the earth's crust

Consider the relationship between the earth's crust and lithosphere. Compare their thickness.

Remember why there is a layer of plastic material in the mantle. Determine from the drawing the depth at which it lies.

Find in the figure the boundaries of separation and the boundaries of collision of lithospheric plates.

Lithosphere is the solid shell of the Earth, consisting of the earth's crust and the upper part of the mantle.

Under the lithosphere there is a heated plastic layer of the mantle. The lithosphere seems to float on it. At the same time, she moves to different directions: rises, falls and slides horizontally. Together with the lithosphere, the earth's crust - the outer part of the lithosphere - also moves.

Rice. 44. Main lithospheric plates

The lithosphere is not monolithic. It is divided by faults into separate blocks - lithospheric plates (Fig. 44). In total, there are seven very large lithospheric plates and several smaller ones on Earth. Lithospheric plates interact with each other in different ways. Moving along the plastic layer of the mantle, they move apart in some places and collide with each other in others.

Questions and tasks

1. What two types of earth's crust do you know?
2. How is the lithosphere different from the earth's crust?
3. What lithospheric plate do you live on?

The rocky shell of the Earth - the earth's crust - is firmly attached to the upper mantle and forms a single whole with it -. The study of the earth's crust and lithosphere allows scientists to explain the processes occurring on the Earth's surface and anticipate changes in the appearance of our planet in the future.

Structure of the earth's crust

The earth's crust, consisting of igneous, metamorphic and sedimentary rocks, on continents and under oceans has different thickness and structure.

It is customary to distinguish three layers in the continental crust. The upper layer is sedimentary, in which sedimentary rocks predominate. The two lower layers are conventionally called granite and basalt. The granite layer consists primarily of granite and metamorphic rocks. The basalt layer is made of denser rocks, comparable in density to basalts. Oceanic crust has two layers. In it, the upper layer - sedimentary - has a small thickness, the lower layer - basalt - consists of basalt rocks, and there is no granite layer.

The thickness of the continental crust under the plains is 30-50 kilometers, under the mountains - up to 75 kilometers. The oceanic crust is much thinner, its thickness is from 5 to 10 kilometers.

There is a crust on other terrestrial planets, on the Moon and on many satellites of the giant planets. But only the Earth has two types of crust: continental and oceanic. On other planets, in most cases it consists of basalts.

Lithosphere

The rocky shell of the Earth, including the crust and the upper part of the mantle, is called the lithosphere. Beneath it there is a heated plastic layer of the mantle. The lithosphere seems to float on this layer. The thickness of the lithosphere in different regions of the Earth varies from 20 to 200 kilometers or more. In general, it is thicker under continents than under oceans.

Scientists have found that the lithosphere is not monolithic, but consists of. They are separated from each other by deep faults. There are seven very large and several smaller lithospheric plates, which constantly but slowly move along the plastic layer of the mantle. The average speed of their movement is about 5 centimeters per year. Some plates are entirely oceanic, but most have different types of crust.

Lithospheric plates move relative to each other in different directions: either they move away, or, conversely, they come closer and collide. As part of the lithospheric plates, their upper “floor” - the earth’s crust - also moves. Due to the movement of lithospheric plates, the location of continents and oceans on the Earth's surface changes. The continents either collide with each other or move thousands of kilometers away from each other.

Our Earth consists of many layers piled on top of each other. However, what we know best is 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 resources available to us. natural resources. But the upper shells of the Earth still preserve millions of years of history of our planet and the entire solar system.

Lithosphere and crust - 2 in 1

These two concepts appear so often in the press and literature that they have entered the 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 - earth's crust

If we divide the Earth into layers, guided by differences in chemical composition, the top layer of the planet will be the earth's crust. 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 crust, in mountainous areas, is thickest. Although 75% of the crust's mass is composed only of silicon and oxygen (not pure, bound in different substances), it has the greatest chemical diversity of all layers of the Earth.

The wealth of minerals also plays a role - various substances and mixtures created over billions of years of the planet’s history. The Earth's crust contains not only "native" minerals that were created by geological processes, but also massive organic heritage, such as oil and coal, as well as alien, meteorite inclusions.

Physical aspect - lithosphere

Based on the physical characteristics of the Earth, such as hardness or elasticity, we will get a slightly different picture - the interior of the planet will be enveloped by the lithosphere (from the Greek lithos, “rocky, hard” and “sphaira” sphere). It is much thicker than the earth's crust: the lithosphere extends up to 280 kilometers deep and even covers the upper solid part of the mantle!

The characteristics of this shell fully correspond to the name - it is the only one, besides the inner core, hard layer Earth. Strength, however, is relative - the Earth’s lithosphere is one of the most mobile in solar system, which is why the planet has changed its appearance more than once. But significant compression, curvature and other elastic changes require thousands of years, if not more.

An interesting fact is that the planet may not have a surface crust. Thus, the surface of Mercury is its solidified 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 hard shell of the Earth. Initially they had almost the same composition. But when the depths were affected only by the underlying asthenosphere and high temperatures, the hydrosphere, atmosphere, meteorite remains 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 different types of landscapes on it. Of course, air and water played an incredibly important role, 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 bombardment by meteorites. And on Earth they were formed as a result of hundreds and thousands of millions of years of movement of lithospheric plates.

You've 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:

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

Thus, the driving force behind the 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 fall back down. Considering that the continents differ in size, and the topography of their lower side mirrors the irregularities of the upper side, they also move unevenly and inconsistently.

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 several hundred million years. In addition, the strength and activity of continental movement is determined by 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 do not necessarily have to be powered by the internal self-heating of the planet. For example, Io, a moon of Jupiter, has many active volcanoes. But the energy for this is not provided by the satellite’s core, but by gravitational friction with Jupiter, due to which Io’s interior heats up.

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

1. Australian
2. Antarctic
3. African
4. Eurasian
5. Hindustan
6. Pacific
7. North American
8. 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 the Ural Mountains, one of the oldest on Earth, were formed. Scientists to this day continue to study faults and the ocean floor, discovering new plates and clarifying the boundaries of old ones.

Geological activity

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

However, there are exceptions - so-called hot spots, which can also exist deep in lithospheric plates. In them, molten flows of asthenosphere matter break upward, melting 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 believe that the “drowned” parts of the lithosphere are melting, increasing pressure in the depths of the mantle and thereby creating upward flows. This can explain the anomalous distance of some hot spots from tectonic faults.

An interesting fact is that shield volcanoes, characterized by their flat shape, often form in hot spots. They erupt many times, growing due to flowing lava. This is also a typical alien volcano format. The most famous of them is the Olympus volcano on Mars, the highest point on the planet - its height reaches 27 kilometers!

Oceanic and continental crust of the Earth

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

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 continents. Part of the continental crust is under water, in the zone of stable lithospheric plates.

The continental crust, on the contrary, is located in stable areas of the lithosphere - its age in some areas exceeds 2 billion years, and some minerals were born along with the Earth! The absence of active destructive processes allowed the development of a thick layer of sedimentary rocks, as well as the preservation of layers from different eras of the planet’s development. This also made it possible to create metamorphic substances - minerals formed due to the exposure of sedimentary or igneous rocks to unusual conditions. Diamonds are prime examples of such minerals.

Lithosphere and crust of the Earth in astronomy

Studying the Earth rarely happens just like that - often the searches of scientists have a very clear practical goal. This is especially relevant in the study of the lithosphere: at the junctions of lithospheric plates, whole placers of ores and valuable minerals come out, for the extraction of which in another place it would be necessary to drill a many-kilometer well. Much data about the earth's crust was obtained thanks to the oil field - in the search for oil and gas deposits, scientists learned a lot about the internal mechanisms of our planet.

Therefore, it is not for nothing that astronomers strive for a detailed study of the crust of other planets - its outlines and appearance reveal the entire internal structure of a space object. For example, on Mars, volcanoes are very high and erupt repeatedly, while on Earth they constantly migrate, appearing periodically in new places. This indicates that on Mars there is no such active movement of lithospheric plates as on Earth. Together with the absence of a magnetic field, the stability of the lithosphere became the main evidence of the stopping of the red planet’s core and the gradual cooling of its interior.
spacegid.com/li…

Among the layers that form our planet are the earth's crust and the lithosphere. However, not everyone understands whether we are talking about two objects separate from each other or in different words mean the same thing. To clarify the subject matter, let’s find out how the earth’s crust differs from the lithosphere.

Definition

Earth's crust- the outer, relatively thin shell of the Earth, bordering the mantle below.

Structure of the Earth

Lithosphere– the shell of the Earth, covering the entire earth’s crust and partly the mantle (its upper layer).

Comparison

Thus, talking directly about the difference between the earth’s crust and the lithosphere is somewhat illogical, since the earth’s crust is one of the components of the lithosphere. However, in some cases, the object of observation is precisely the earth’s crust, and in others, a more extensive zone, which also includes the mantle layer.

For example, information concerning the structure of the earth’s crust is of great importance for science. It is considered as a heterogeneous shell of the Earth in its composition. It has been established that under the waters of the oceans the crust has sedimentary and basalt layers, and in open areas of the planet (continents) it also contains an extensive granite layer. In addition, there are transitional areas, during which a smooth “flow” of the continental crust into the oceanic crust occurs. Why is it necessary to know about the structure of the earth's crust? For example, in order to determine the location of minerals.

Now let's turn to the study of the lithosphere. The emphasis in this case is on the processes occurring in it. It was found that the mantle layer within the lithosphere is rigid. And below is a plastic mantle:

The lithosphere itself, according to research, consists of plates different sizes. These plates are movable. They move very slowly but constantly along the soft mantle, sometimes approaching each other, sometimes diverging. The earth's crust, which is part of the lithospheric plates, is also in continuous motion, which leads to changes in the location of continents and oceans on the surface of the planet.

Observations of ongoing processes make it possible to explain many phenomena and predict natural disasters, such as earthquakes and landslides. The data obtained also helps to select the most suitable places for the construction of some facilities. In addition, research makes it possible to predict what the Earth will look like in the future.

So, trying to answer the question of what is the difference between the earth’s crust and the lithosphere, we have established that these names should not be identified with each other. In certain cases, it is appropriate to consider the earth’s crust as an independent object; in others, the lithosphere and the processes occurring in it are significant as a whole.