The internal structure and topography of the Earth

4. Movement earth's crust

The earth's crust only seems to be motionless, absolutely stable. In fact, it performs continuous and varied movements. Some of them occur very slowly and are not perceived by the human senses, others, such as earthquakes, are landslide, destructive. What titanic forces move the earth's crust?

The internal forces of the Earth, the source of their origin. It is known that at the boundary between the mantle and the lithosphere, the temperature exceeds 1500 °C. At this temperature, matter must either melt or turn into a gas. During the transition solids into liquid or gaseous state their volume should increase. However, this does not happen, since the overheated rocks are under pressure from the overlying layers of the lithosphere. There is a "steam boiler" effect, when matter tending to expand puts pressure on the lithosphere, setting it in motion together with the earth's crust. Moreover, the higher the temperature, the stronger the pressure and the more actively the lithosphere moves. Particularly strong pressure centers arise in those places of the upper mantle where radioactive elements are concentrated, the decay of which heats the constituent rocks to even higher temperatures. Movements of the earth's crust under the influence of internal forces The earth is called tectonic. These movements are divided into oscillatory, folding and discontinuous.

oscillatory movements. These movements occur very slowly, imperceptibly to humans, which is why they are also called secular or epeirogenic. In some places the earth's crust is rising, in others it is falling. In this case, the uplift is often replaced by a lowering, and vice versa. These movements can be traced only by those "traces" that remain after them on the earth's surface. For example, on the coast mediterranean sea, near Naples, are the ruins of the temple of Serapis, the columns of which are sea ​​shellfish at a height of up to 5.5 m above the level modern sea. This serves as unconditional proof that the temple, built in the 4th century, was at the bottom of the sea, and then it was raised. Now this piece of land is sinking again. Often on the coasts of the seas above them modern level there are steps - sea terraces, once created by the sea surf. On the platforms of these steps, you can find the remains of marine organisms. This indicates that the platforms of the terraces were once the bottom of the sea, and then the coast rose and the sea receded.

The lowering of the earth's crust below 0 m above sea level is accompanied by the advance of the sea - transgression, and the rise - by its retreat - regression. At present, in Europe, uplifts occur in Iceland, Greenland, and the Scandinavian Peninsula. Observations have established that the region of the Gulf of Bothnia is rising at a rate of 2 cm per year, i.e., 2 m per century. At the same time, the territory of Holland, southern England, northern Italy, the Black Sea lowland, and the coast of the Kara Sea are sinking. A sign of the lowering of the sea coasts is the formation of sea bays in the mouth sections of rivers - estuaries (lips) and estuaries.

With the rise of the earth's crust and the retreat of the sea, the seabed, composed of sedimentary rocks, turns out to be land. This is how vast marine (primary) plains are formed: for example, the West Siberian, Turan, North Siberian, Amazonian (Fig. 20).

Rice. 20. The structure of the primary, or marine, reservoir plains

Folding movements. In cases where rock layers are sufficiently plastic, under the action of internal forces, they are crushed into folds. When the pressure is directed vertically, the rocks are displaced, and if in the horizontal plane, they are compressed into folds. The shape of the folds is the most diverse. When the bend of the fold is directed downward, it is called a syncline, upward - an anticline (Fig. 21). Creases form in great depths, i.e. at high temperatures and high pressure, and then under the influence of internal forces, they can be lifted. This is how the folded mountains of the Caucasus, the Alps, the Himalayas, the Andes, and others arise (Fig. 22). In such mountains, folds are easy to observe where they are exposed and come to the surface.

Rice. 21. Synclinal (1) and anticlinal (2) folds

Rice. 22. Fold mountains

Breaking movements. If rocks are not strong enough to withstand the action of internal forces, cracks form in the earth's crust - faults and vertical displacement of rocks occurs. The descended areas are called grabens, and the raised ones are called horsts (Fig. 23). The alternation of horsts and grabens creates blocky (reborn) mountains. Examples of such mountains are: Altai, Sayan, Verkhoyansk Range, Appalachians in North America and many others. The revived mountains differ from the folded ones both in internal structure and in appearance- morphology. The slopes of these mountains are often steep, the valleys, like the watersheds, are wide and flat. Rock layers are always displaced relative to each other.

Rice. 23. Restored fold-block mountains

The sunken areas in these mountains, the grabens, are sometimes filled with water, and then deep lakes are formed: for example, Baikal and Teletskoye in Russia, Tanganyika and Nyasa in Africa.

Analysis demographic situation V Russian Federation

Migration volume indicators are absolute numbers migrations or migrants. These numbers may not coincide with each other due to the fact that the same person can migrate several times during the study period. Hence...

England

The changes taking place in England were also reflected in the field of ideology. In the second half of the 14th century, a broad movement for the reform of the Catholic Church unfolded in England ...

Influence of solar radiation on the geographic envelope of the Earth

As we already know, direct solar radiation, when passing through the atmosphere, it reaches the earth's surface weakened by atmospheric absorption and scattering. Also, there are always clouds in the atmosphere...

Internal structure and the relief of the earth

Science has established that more than 2.5 billion years ago, the planet Earth was completely covered by the ocean. Then, under the action of internal forces, the uplift of individual sections of the earth's crust began. The process of uplift was accompanied by violent volcanism...

Patterns and indicators of population distribution

The decline in the population of Russia and its aging is due to the unfavorable dynamics of birth and death rates. Figure 5 General indicators fertility and mortality. During the period...

The term "earth's crust" was introduced into literature by C. Layey in 1835. In the 19th century, this term meant only the surface visible to the human eye, rocks ...

Continental and oceanic crust: Comparative characteristics

The largest and most famous building blocks the earth's crust are continents and oceans, differing in structure. It is worth noting that this information should not be taken literally, i.e. ...

Glaciers of Altai

Glacier movement - viscoplastic flow and / or block sliding of ice along the bed and intraglacial ruptures and chips, from the feeding area to the end of the glacier. The speed depends on the thickness of the ice, the slope of the bed, the temperature...

Formation and evolution of the Earth

lithospheric relief-forming earth nebula large blocks Earth's lithosphere, located in in constant motion and limited by active fault zones. Theory...

General economic and geographical characteristics of Russia

Natural movement - natural regulator biological process all living things on Earth, including humans, manifested through such indicators as fertility, mortality ...

There are several hypotheses about the origin of the Earth. According to modern concepts, about 5 billion years ago, the condensation of a gas-dust cloud that fell into the gravitational field of the Sun ...

The main features of the development of the geosphere and the planetary differentiation of its landscapes

The degree of human alteration of landscapes is closely related to the size of the population, the energy base of the productive forces aimed at the development and use of the territory, as well as the duration of its exploitation...

Features of the distribution of the population in the world and the factors that determine them

The reproduction (natural movement) of the population is the most characteristic property of the population, which is studied by the science of demography. To use the simplest definition she has in her arsenal...

The Gulf Stream system of currents and its significance for geographical envelope

In the western part of the ocean, a branch of the South Trade Wind Current (Guiana Current) and the North Trade Wind Current enter the Caribbean Sea and form a backwater in the Gulf of Mexico, the excess of which rushes (at a speed of about 1 ...

Coordinate and height systems used in the Republic of Belarus

At present, a wide range of users have become available not only software products operating with a wide variety of coordinate systems and projections, but also navigation tools ...

Slow movements of the earth's crust. It seems to people that the surface of the Earth is motionless. In fact, every section of the earth's crust rises or falls, shifts to the right or left, forward or backward. But these movements are so slow that we usually don't notice them. However, scientists use very precise instruments to “see” these movements and measure their speed.

The ancient Greeks already knew that the earth's surface experiences ups and downs. The inhabitants of the Scandinavian Peninsula also guessed this: their ancient coastal settlements, after several centuries, were far from the sea.

The movements of the earth's crust, depending on the direction, are divided into vertical and horizontal. They appear simultaneously, accompanying each other.

Horizontal movements of the earth's crust are movements parallel to the surface of the earth.

Horizontal movements occur due to the movement of lithospheric plates. Continents move with the plates. The speed of horizontal movements is small - a few centimeters per year. However, they keep their direction very for a long time, therefore, over many millions of years, the continents move hundreds and thousands of kilometers relative to each other (Fig. 47).

Rice. 47. Change in the position of the continents

Australia and South America moving away from each other at a rate of 3 cm per year. Calculate how many kilometers they will move in 10 million years.

Horizontal movements play huge role in the formation of the earth's relief. Mountains form at the boundaries of lithospheric plates (Fig. 48).

Rice. 48. Formation of mountains: a - in the collision of lithospheric plates; b - when moving apart lithospheric plates

When lithospheric plates collide, rock layers are crushed into folds and land mountains are formed (Fig. 48, a). Where the plates move apart, mountain ranges form on the ocean floor. They consist of igneous rocks that have poured out to the bottom - basalts (Fig. 48, b).

Vertical movements of the earth's crust are movements perpendicular to the surface of the earth.

Vertical movements raise or lower individual parts of the land and the bottom of the oceans (Fig. 49). The sinking land is flooded by the sea, the rising bottom of the sea, on the contrary, becomes land.

Rice. 49. Slow uplifts of the earth's crust and an increase in land area in southwestern Finland

Vertical movements, unlike horizontal ones, often change their direction: ascending sections may begin to descend and then rise again.

The speed of modern vertical movements on the plains is small - up to several millimeters per year. Mountains can "grow" by several centimeters per year.

Rice. 50. Occurrence of rocks: a - horizontal; b - folded (rocks are crumpled into folds)

Movements of the earth's crust and the occurrence of rocks. The movements of the earth's crust change the occurrence of rocks. Sedimentary rocks accumulate in the oceans and seas in horizontal layers (Fig. 50, a). However, in the mountains, layers of the same rocks are crumpled into folds (Fig. 50, b). The rocks are crumpled into folds slowly, over millions of years.

Rice. 51. Displacement of the earth's crust

• Reset- a block of the earth's crust that has descended along a fault relative to another block. A ledge appears on the earth's surface.
• Horst- an uplifted area of ​​the earth's crust, bounded by faults. Horsts form mountain ranges with flat tops.
• Graben- lowered area of ​​the earth's crust, limited by faults. Graben depressions often serve as lake basins.

Calculate how high the mountains could acquire in a million years if they did not collapse, and the uplift would occur at a rate of 1 cm per year.

Vertical movements, like horizontal ones, form the relief: the outlines of the seas and continents, the height of individual land areas and the depth of sea depressions depend on them.

Thicknesses of rocks can be not only crumpled into folds. The pictures from space show that the Earth is divided into large and small sections-blocks by a dense network of faults (cracks). These blocks are displaced relative to each other, forming different forms relief (Fig. 51).

Questions and tasks

1. What landforms can be formed as a result of horizontal movements of the earth's crust?
2. What movements of the earth's crust change the shape of the continents?
3. What is the primary occurrence of sedimentary rocks? How can it change?

see Secular fluctuations.

• - vertical movements that unambiguously and simultaneously manifest themselves over vast areas, including both geosynclines and platforms ...

  Geological Encyclopedia

• - a zone of the earth's crust at a small depth from the day surface, where rocks have constant temperature close to the mean annual air temperature...

  Dictionary of hydrogeology and engineering geology

• Natural science. encyclopedic Dictionary

• - 1. Shore forming in areas experiencing positive flow. movement. 2...

  Geological Encyclopedia

• - radiological methods allow to estimate V. h. to. or, more precisely, the age of the most ancient parts of the earth's surface ...

  Geological Encyclopedia

• - One of the main phenomena in the life of the earth's crust are those changes in its configuration and its appearance, which are due to the displacement of the boundaries of land and sea. Continents and seas are no different, as one might think, ...

  Encyclopedic Dictionary of Brockhaus and Euphron

• - see Century fluctuations ...

  Encyclopedic Dictionary of Brockhaus and Euphron

• - about 70% of the earth's crust is covered with water of the oceans and seas, and this circumstance has a huge impact on its R. Under water, as well as on land, there are processes that change the height and R. of the crust, processes that are described in Art. Mountains...

  Encyclopedic Dictionary of Brockhaus and Euphron

• - slow, long-lasting uplift and subsidence of the earth's surface, caused by vertical movements of the earth's crust. See also Vibrational movements of the earth's crust....
• - movements of the earth's crust, causing the movement of the earth's surface in a direction perpendicular to it, that is, parallel to the radius of the earth. Usually referred to as the oscillatory movements of the earth's crust ...

  Great Soviet Encyclopedia

• - wave-like oscillatory movements of the earth's crust, conjugated long-term uplifts and lowerings of adjacent sections of the earth's surface ...

  Great Soviet Encyclopedia

• - tangential movements of the earth's crust, movements occurring in a direction parallel to the earth's surface. Contrasted with vertical movements of the cortex...

  Great Soviet Encyclopedia

• - slow ups and downs of the earth's crust, occurring everywhere and continuously ...

  Great Soviet Encyclopedia

• - Siberian branch RAS - organized in 1957 in Irkutsk. Studies of the structure of the earth's crust and processes in deep zones, as well as the patterns of formation of minerals...
• - everywhere and constantly manifesting slow uplifts and lowerings of the earth's crust, replacing each other in time and space ...

  Big encyclopedic dictionary

"Uplifts of the earth's crust" in books

III. FORMATION OF THE EARTH'S CRUST

author author unknown

CHAPTER 3 Evolution of the earth's crust. Continental drift and ocean floor spreading. mantle convection

From the book Amazing Paleontology [History of the Earth and Life on It] author Eskov Kirill Yurievich

CHAPTER 3 Evolution of the earth's crust. Continental drift and ocean floor spreading. Mantle convection The rocks that form the Earth's crust, as we remember, are igneous - primary, formed during the cooling and solidification of magma, and sedimentary - secondary,

author Efremov Ivan Antonovich

III. FORMATION OF THE EARTH'S CRUST

From the book History of Origin and Development globe author author unknown

III. FORMATION OF THE EARTH'S CRUST The fiery-liquid state of the earth ended, as we have seen, with the formation of a fused crust, which was completely covered by water. How did real continents, rising above the water in the form of islands, and those various masses of stones and layers of earth,

How we learned to read the history of the earth's crust

From the book Secrets of the Past in the Depths of Time author Efremov Ivan Antonovich

How we learned to read the history of the earth's crust In the previous chapter, we tried to take a look at great book nature. But this is also the general idea could have been formed only as a result of the hard work of outstanding minds, both the founders of geological science and the remaining

Relaxation of the earth's crust.

From the book Theoretical Geography author Votyakov Anatoly Alexandrovich

Relaxation of the earth's crust. The first thought that comes to mind when faced with Hall's paradox sounds somewhat unusual, but in fact it is completely natural: in a normal state, the earth's crust perfectly holds everything that is on it, but during

From the book 100 great records of the elements author

The most important builder of the earth's crust The earth's crust lies on the rocks of the upper mantle, between them there is an exchange of deep matter. Geologists cannot refuse this idea in any way, although many are against it. And for it ... we will not give all the arguments, one is enough

The main builder of the earth's crust

From the book 100 Great Records of the Elements [with illustrations] author Nepomniachtchi Nikolai Nikolaevich

The most important builder of the earth's crust The earth's crust lies on the rocks of the upper mantle, between them there is an exchange of deep matter. Geologists cannot refuse this idea in any way, although many people are against it. And for her ... we will not give all the arguments, one is enough

Gases of the earth's crust

From the book Big Soviet Encyclopedia(GA) author TSB

Secular oscillations of the earth's crust

TSB

Vertical movements of the earth's crust

From the book Great Soviet Encyclopedia (BE) of the author TSB

Wave motions of the earth's crust

From the book Great Soviet Encyclopedia (VO) of the author TSB

Horizontal movements of the earth's crust

From the book Great Soviet Encyclopedia (GO) of the author TSB

Vibrational movements of the earth's crust

From the book Great Soviet Encyclopedia (KO) of the author TSB

Divisibility of the earth's crust

From the book Great Geological Discoveries author Romanovsky Sergey Ivanovich

Divisibility of the earth's crust People who are far from our science think that geologists study the earth as a whole. This, of course, is not true. The geologist is not able, either with a hammer, or with deep-sea submersible vehicles, or even as a result of drilling the so-called