What are mountains and plains. Plains, their classification. Subdivision of the plains by absolute height. Landforms associated with continental glaciation. What are called plains

Plains- vast areas of the earth's surface with small (up to 200 m) elevation fluctuations and slight slopes.

Plains occupy 64% of the land area. In tectonic terms, they correspond to more or less stable platforms that have not shown significant activity in recent times, regardless of their age - they are ancient or young. Most of the plains on land are located on ancient platforms (42%).

According to the absolute height of the surface, plains are distinguished negative- lying below the level of the World Ocean (Caspian), base- from 0 to 200 m in height (Amazonian, Black Sea, Indo-Gangetic lowlands, etc.), sublime- from 200 to 500 m (Central Russian, Valdai, Volga Uplands, etc.). Plains also include plateau(high plains), which, as a rule, are located above 500 m and are separated from the adjacent plains by ledges (for example, the Great Plains in the USA, etc.). The height of the plains and plateaus determines the depth and degree of their dissection by river valleys, gullies and ravines: the higher the plains, the more intensely they are dissected.

In appearance, plains can be flat, wavy, hilly, stepped, and according to the general slope of the surface - horizontal, inclined, convex, concave.

Different appearance plains depends on their origin and internal structure, which largely depend on the direction of neotectonic movements. On this basis, all plains can be divided into two types - denudation and accumulative (see Scheme 1). Within the former, the processes of denudation of loose material predominate, within the latter, its accumulation.

It is quite obvious that denudation surfaces experienced ascending tectonic movements for most of their history. It is thanks to them that the processes of destruction and demolition - denudation - prevailed here. However, the duration of denudation can be different, and this is also reflected in the morphology of such surfaces.

With continuous or almost continuous slow (epeirogenic) tectonic uplift, which continued throughout the entire existence of the territories, there were no conditions for the accumulation of sediments on them. There was only a denudation cut of the surface by various exogenous agents, and if thin continental or marine sediments accumulated for a short time, then during subsequent uplifts they were carried outside the territory. Therefore, in the structure of such plains, an ancient base comes to the surface - folds cut by denudation, only slightly covered by a thin cover of Quaternary deposits. Such plains are called basement; it is easy to see that the basement plains in tectonic terms correspond to the shields of ancient platforms and the protrusions of the folded basement of young platforms. Basement plains on ancient platforms have a hilly relief, most often they are elevated. Such, for example, are the plains of Fennoscandia - the Kola Peninsula and Karelia. Similar plains are located in northern Canada. Basement hills are widespread in Africa. As a rule, long-term denudation cut off all the structural irregularities of the base, so such plains are astructural.

The plains on the "shields" of young platforms have a more "restless" hilly relief, with residual hill-type elevations, the formation of which is associated either with lithological features - harder stable rocks, or with structural conditions - former convex folds, microhorsts or exposed intrusions. Of course, all of them are structurally determined. This is how, for example, the Kazakh upland, partly the Gobi plains look like.

Plates of ancient and young platforms, which experience steady uplift only during the neotectonic stage of development, are composed of layers of sedimentary rocks of great thickness (hundreds of meters and a few kilometers) - limestones, dolomites, sandstones, siltstones, etc. Over millions of years, the sediments have hardened, become rocky and acquired stability to washout. These rocks lie more or less horizontally, as they once were deposited. The uplift of territories during the neotectonic stage of development stimulated denudation on them, which made it impossible for young loose rocks to be deposited there. Plains on the plates of ancient and young platforms are called reservoir. From the surface, they are often covered by loose Quaternary continental deposits of small thickness, which practically do not affect their height and orographic features, but determine their appearance due to morphosculpture (East European, southern part of West Siberian, etc.).

Since the stratified plains are confined to the platform plates, they are pronounced structural - their macro- and even mesoforms of the relief are determined by the geological structures of the cover: the nature of the bedding of rocks of different hardness, their slope, etc.

During the Pliocene-Quaternary subsidence of territories, even if relative, they began to accumulate sediments carried from the surrounding areas. They filled in all the previous surface irregularities. So formed accumulative plains, composed of loose, Pliocene-Quaternary deposits. Usually these are low-lying plains, which sometimes lie even below sea level. According to the conditions of sedimentation, they are divided into marine and continental - alluvial, eolian, etc. An example of accumulative plains is the Caspian, Black Sea, Kolyma, Yano-Indigirskaya lowlands, composed of marine sediments, as well as Pripyat, Lena-Vilyui, La Plata and others. Accumulative plains, as a rule, are confined to syneclises.

In large basins among the mountains and at their foothills, the accumulative plains have a surface inclined from the mountains, cut through by the valleys of many rivers flowing down from the mountains and complicated by their alluvial fans. They are composed of loose continental sediments: alluvium, proluvium, deluvium, lacustrine sediments. For example, the Tarim Plain is composed of sands and loesses, the Dzungarian Plain is composed of thick sand accumulations brought from neighboring mountains. The ancient alluvial plain is the Karakum desert, composed of sands brought by rivers from the southern mountains in the pluvial epochs of the Pleistocene.

Plain morphostructures usually include ridges. These are linearly elongated hills with rounded outlines of peaks, usually no more than 500 m high. They are composed of dislocated rocks of different ages. An indispensable feature of the ridge is the presence of a linear orientation inherited from the structure of the folded area on the site of which the ridge arose, for example, the Timan, Donetsk, Yenisei.

It should be noted that all the listed types of plains (basement, stratal, accumulative), as well as plateaus, plateaus and ridges, according to I. P. Gerasimov and Yu. structure.

Plains on land form two latitudinal series corresponding to the platforms of Laurasia and Gondwana. Northern range of plains formed within the relatively stable in modern times ancient North American and East European platforms and the young Epipaleozoic West Siberian platform - a plate that experienced even a slight subsidence and was predominantly a low-lying plain expressed in relief.

The Central Siberian Plateau, and in the morphostructural sense, these are high plains - a plateau, formed on the site of the ancient Siberian platform, activated in recent times due to resonant movements from the east, from the side of the active geosynclinal West Pacific belt. The so-called Central Siberian Plateau includes volcanic plateaus(Putorana and Siverma), tuff plateaus(Central Tunguska), trap plateaus(Tungusskoye, Vilyuiskoye), formation plateaus(Priangarskoe, Prilenskoe), etc.

The orographic and structural features of the plains of the northern row are peculiar: beyond the Arctic Circle, low coastal accumulative plains predominate; to the south, along the so-called active 62° parallel, there is a strip of basement hills and even plateaus on the shields of ancient platforms - Laurentian, Baltic, Anabar; in middle latitudes along 50° N. sh. - again a strip of stratal and accumulative lowlands - North German, Polish, Polissya, Meshchera, Sredneobskaya, Vilyuiskaya.

On the East European Plain, Yu.A. Meshcheryakov also revealed another pattern: the alternation of lowlands and uplands. Since the movements on the East European Platform were of an undulating nature, and their source in the neotectonic stage was the collisions of the Alpine belt, he established several alternating bands of uplands and lowlands, fanning out from southwest to east and taking on an increasingly meridional direction as they move away from the Carpathians. . The Carpathian strip of uplands (Volynskaya, Podolskaya, Pridneprovskaya) is replaced by the Pripyat-Dnieper lowland strip (Pripyatskaya, Pridneprovskaya), then follows the Central Russian strip of uplands (Belarusian, Smolensk-Moscow, Central Russian); the latter is replaced successively by the Upper Volga-Don strip of lowlands (Meshcherskaya lowland, Oka-Donskaya plain), then by the Volga upland, Zavolzhskaya lowland and, finally, by the strip of Cis-Ural uplands.

In general, the plains of the northern row are inclined to the north, which is consistent with the course of the rivers.

Southern range of plains corresponds to the Gondwanan platforms that have experienced activation in recent times. Therefore, within its limits, elevations predominate: layered (in the Sahara) and basement (in southern Africa), as well as plateaus (Arabia, Hindustan). Only within the limits of the inherited troughs and syneclises did stratal and accumulative plains form (the Amazonian and La Plata lowlands, the Congo depression, and the Central Lowland of Australia).

In general, the largest areas among the plains on the continents belong to layered plains, within which the primary plain surfaces are formed by horizontal layers of sedimentary rocks, and the socle and accumulative plains are of subordinate importance.

In conclusion, we emphasize once again that mountains and plains, as the main forms of relief on land, are created by internal processes: mountains gravitate towards mobile folded belts.

Lands, and plains - to platforms (Table 14). Relatively small, relatively short-lived landforms created by external exogenous processes are superimposed on large ones and give them a peculiar appearance. They will be discussed below.

Plains are very large areas of the earth's surface, the height fluctuations on which are small, and the existing slopes are insignificant. They are distinguished by absolute height and by the method of formation, or, in other words, by origin. What are the plains in terms of height and origin?

What are the plains in height

According to the absolute height, the plains are divided into lowlands, uplands, and plateaus. A lowland is a plain, the highest parts of which do not exceed 200 meters above sea level. Examples of such plains are the Caspian or Amazonian lowlands.

If the elevation difference of the earth's surface on a plain is in the range from 200 to 500 meters, then it is called a hill. In Russia, such plains include, for example, the Central Russian Upland or the Volga Upland.

Plateaus or, in other words, upland plateaus are plains located above half a kilometer above sea level. This, for example, is the Central Siberian Plateau or the Great Plains located in North America.

What are the plains by origin

By origin, alluvial (or, in other words, accumulative), denudation, marine, continental accumulative, water-glacial, abrasion and reservoir plains are distinguished.

Alluvial plains are formed as a result of many years of deposition and accumulation of river sediments. Examples of such plains are the Amazonian and La Plata lowlands.

Denudation plains are formed as a result of the long destruction of mountainous terrain. This, for example, is the Kazakh upland.

Sea plains are located along the coasts of the seas and oceans and they were formed as a result of the retreat of the sea. An example of such a plain is the Black Sea Lowland.

Continental accumulative plains are located at the foot of the mountains and they were formed as a result of the deposition and accumulation of rocks brought by water flows. Examples of such a plain are the Kuban or Chechen plains.

Water-glacial plains are called plains that were once formed as a result of the activity of a glacier, such as Polesie or Meshchera.

Abrasive plains were formed as a result of the destruction of the coastline of the seas by waves and surf.

Stratum plains make up 64% of all plains on the continents. They are located on platforms. earth's crust, but are composed of layers of sedimentary rocks. Examples of such plains are the East European, West Siberian and many others.

Earth's surface. On land, plains occupy about 20% of the area, the most extensive of them are confined to and. All plains are characterized by small fluctuations in elevation and slight slopes (slopes reach 5 °). According to the absolute height, the following plains are distinguished: lowlands - from 0 to 200 m (Amazonian);

• elevations - from 200 to 500 m above ocean level (Central Russian);
• upland, or plateaus - over 500 m above ocean level ();
• Plains lying below ocean level are called depressions (Caspian).

According to the general nature of the surface of the plain, there are horizontal, convex, concave, flat, hilly.

According to the origin of the plains, the following types are distinguished:

• marine accumulative(cm. ). Such, for example, is the lowland with its sedimentary cover of young marine strata;
• continental accumulative. They were formed as follows: at the foot of the mountains, the products of destruction carried out from them by water flows are deposited. Such plains have a slight slope to sea level. These most often include marginal lowlands;
• river accumulative. They are formed due to the deposition and accumulation of loose rocks brought ();
• abrasion plains(see Abrasion). They arose as a result of the destruction of the coast by the activity of the sea. These plains arise the faster, the weaker the rocks and the more often the unrest;
• structural plains. They have a very complex origin. In the distant past they were mountainous countries. Over the course of millions of years, the mountains were destroyed by external forces, sometimes to the stage of almost plains (peneplains), then as a result, cracks and faults arose, along which it poured out to the surface; she, like armor, covered the former unevenness of the relief, her own surface was preserved even or stepped as a result of the outpouring of traps. These are the structural plains.

The surface of the plains, which receive sufficient moisture, is dissected by river valleys, dotted with complex systems of gullies and.

The study of the origin of the plains and the modern forms of their surface is of great economic importance, since the plains are densely populated and developed by man. They have many settlements, a dense network of communications, large and land. Therefore, it is precisely with the plains that one has to deal with when developing new territories, designing the construction of settlements, communication lines, and industrial enterprises. As a result of human economic activity, the relief of the plains can change significantly: ravines are filled up, embankments are built, quarries are formed during open-pit mining, and man-made hills from waste rock - waste heaps - grow near the mines.

The change in the relief of the ocean plains is affected by:

• , eruptions, faults of the earth's crust. The irregularities created by them are transformed by external processes. Sedimentary rocks, settling to the bottom, level it. Most accumulates at the foot of the continental slope. In the central parts of the ocean, however, this process occurs slowly: a layer of 1 mm is created in a thousand years;
• natural currents that erode and transport loose rocks sometimes form underwater dunes.

The largest plains on earth

Plain

Plain

relatively flat surface with slight (up to 300–400 m) elevation fluctuations and a predominance of small (up to 5–10°) slopes; one of the two main types of relief of the globe (the second is mountains). Plains are found on different abs. heights on land and at the bottom of the oceans and seas (underwater plains). On land, plains are distinguished: lowlands, or lowlands located below at. m. (for example, the Caspian lowland), low - at high. up to 200 m, elevated - 200–500 m, upland (plateaus, plateaus), sloping piedmont. The most typical plains for platforms and intermontane depressions. They are characterized by an open horizon line - smooth or wavy, with soft outlines. According to the features of the relief, flat, wavy, ridged, hilly, ridge, stepped (terraced) plains are distinguished. According to the origin and predominance of certain exogenous processes distinguish between structural (eg, plateau), denudation and accumulative plains. Most of the large plains (Russian, West Siberian, Central Siberian, North American, Amazonian) have a complex origin. Plains occupy more than 20% of the land and are the main. areas of human settlement. At the bottom of the seas and oceans, they are subdivided depending on the depth, origin, type of bottom organisms (abyssal, bathyal plains).

Geography. Modern illustrated encyclopedia. - M.: Rosman. Under the editorship of prof. A. P. Gorkina. 2006 .

See what "plain" is in other dictionaries:

Cm … Synonym dictionary

PLAIN, plains, women. The earth's surface without mountains and significant hills. “Mountains are gone; began a plain without end. Nekrasov. “And that’s it, announcing the plain, cheers broke out in the distance.” Pushkin. Dictionary Ushakov. D.N. Ushakov. 1935 1940 ... Explanatory Dictionary of Ushakov

Plain, a large area of ​​the Earth's surface, over which there are no significant fluctuations in altitude. Some plains, such as PENEPLEN, result from the destruction of higher ground. But most of the plains… … Scientific and technical encyclopedic dictionary

PLAIN, s, wives. Flat, without high hills, the earth's surface, as well as (special) part of the bottom of the sea or ocean without sharp fluctuations in height. Russian plains. | adj. flat, oh, oh. R. landscape. Explanatory dictionary of Ozhegov. S.I. Ozhegov, N.Yu. Shvedova… … Explanatory dictionary of Ozhegov

- [it. Flache, Ebenes Land; French plaine pays] a surface, usually significant in area, but with minor elevation fluctuations; if the latter reach several hundred meters (Z. Siberia up to 200 m), then over a long distance, therefore the heights ... ... Geological Encyclopedia

plain- About the size, nature of the surface, color. Boundless, boundless, endless, boundless, boundless, brown, wavy, scorched, faded, smooth, blue, bluish-brown, huge, yellow, green, golden, boundless, ... ... Dictionary of epithets

plain- — EN plain An extensive, broad tract of level or rolling, almost treeless land with a shrubby vegetation, usually at a low elevation. (Source: MGH)… … Technical Translator's Handbook

plain- Relatively flat surfaces, sometimes quite extensive, with little elevation change and little slope... Geography Dictionary

- (Deut. 1:1, Deut. 2:8). Palestine is a mountainous land, and therefore there are few wide plains in it. Remarkable of them are the following: a) the plain of Jezreel, or Ezdrilon. b) a plain running along the Mediterranean Sea from the city of Carmel to the Egyptian stream, c) ... ... Bible. Old and New Testaments. Synodal translation. Bible encyclopedia arch. Nicephorus.

Exist., f., use. comp. often Morphology: (no) what? plains, why? plain, (see) what? plain, what? plain, about what? about the plain; pl. What? plains, (no) what? plains, why? plains, (see) what? plains, what? plains, about what? about the plains ... ... Dictionary of Dmitriev

Ararat Plain in Armenia Plains are areas of the land surface, the bottom of the seas and oceans, which are characterized by: a slight fluctuation in altitude (up to 200 m) and a slight slope of the terrain (up to 5 °). Plains occupy 64% of the land area. ... ... Wikipedia

Books

• Russian plain. The experience of spiritual resistance, . This collection includes materials from the international scientific-practical conference "The Russian Plain. The experience of spiritual resistance", held in January-February 2013 on the initiative of…

How are plains depicted on a physical map? Tell me about a plain that you know well.

1. Flat and hilly plains. Most of the world is occupied by plains. Vast areas of flat or hilly surface of the Earth, some parts of which vary in height, are called plains.
Imagine a flat, treeless steppe covered with grassy vegetation. On such a plain, the horizon is visible from all sides and has a rectilinear outline of the boundaries. This is a flat plain.
Eurasia between the rivers Yenisei and Lena is located Central Siberian plateau. Plateaus also occupy most of Africa.

The second type of plains is hilly plains. The relief of the hilly plains is very complex. Here there are separate hills and hills, ravines and depressions.
The surface of plains usually slopes in one direction. The direction of the flow of the rivers corresponds to this slope. The slope of the plain is clearly visible on the plan and on the map. The plains are the most convenient for human economic activity. Most of the settlements are located on the plains. Flat areas are convenient for agriculture, for the construction of transport routes, industrial buildings. Therefore, man has mastered flat areas since ancient times. At present, the overwhelming majority of the peoples of the globe inhabit flat places.

2. According to the absolute height, three types of plains are distinguished (Fig. 43). Plains with a height of up to 200 m above sea level are called lowlands. On the physical map of the lowlands are depicted in green. The lowlands located near the coast of the sea are lower than its level. These include Caspian lowland in the west of our country. The largest lowland on the globe is the Amazonian in South America.

Rice. 43. Differences of plains in height.

Plains with an absolute height of 200 m to 500 m are called hills (for example, a hill Ustyurt between the Caspian and Aral seas). On physical maps, hills are shown in yellowish color.
Plains with a height of more than 500 m are plateaus. Plateaus on the map are shown in brown.

3. Formation of plains. Plains are divided into several types according to the method of formation. Plains that have been formed as a result of exposure and uplift of the seabed are called primary plains. These plains include the Caspian lowland.
On the globe there are plains formed from river sediments and sediments. On such plains, the thickness of sedimentary rocks, consisting of pebbles, sand, clay, sometimes reaches several hundred meters. These plains are La Plata along the Parana River in South America, in Asia - Great China Plain, Indo-Gangetic And Mesopotage. At the same time, there are plains on the earth's surface formed as a result of the long-term destruction of mountains. Such plains consist of folded layers of hard rocks. Therefore, they are hilly. Examples of rolling plains include the East European Plain And Saryarka plain.
Some plains are formed by lava flows poured onto the earth's surface. In this case, there is a kind of leveling of the existing irregularities. These plains include the following plateaus: Central Siberian, Western Australian, Deccan.

4. Changing the plains. On the plains, slow oscillatory movements are observed due to the influence of internal forces.
Plains undergo various changes under the influence of external forces. Looking at a physical map, you will see how the surface of the earth is indented by rivers and their tributaries. River water, washing away the banks and the sole, forms a valley. Since the lowland rivers flow meandering, they form wide valleys. The greater the slope, the more rivers cut into the surface of the Earth and change its relief.
In spring, meltwater and heavy rain waters create temporary surface currents (watercourses) that form ravines and ditches. Usually ravines are formed on small slopes of hills that are not fastened by plant roots. If you do not take action on ichus in time ­ friction, then the ravines, branching, grow. This can cause great damage to the economy: fields, arable land, gardens, roads, various buildings. To stop the growth of ravines, they are covered with peat, rubble, stones. The bottom and slopes are covered with peat, which creates conditions for the growth of vegetation.
The moat, like the ravine, is an elongated depression. The only difference is that the moat has gentle slopes. Its bottom and slopes are covered with grass and shrubs.
The plains also change under the influence of the wind. The wind destroys solid rocks and carries away their particles. In deserts, steppes, on arable lands and on the shores of the seas, the effect of the wind is very noticeable. On the coasts of the seas or large lakes, you can see sand ridges formed by waves. The wind blowing from the sea surface easily carries away dry sand from the shores. The grains of sand are moved by the wind until they encounter some kind of obstacle (bush, stone, etc.). Sand, accumulating in this place, gradually takes the form of elongated mounds, on the side where the wind blows, the slopes are gentle, and on the other - steeper. The two lower edges of the mound are elongated and gradually decrease, therefore, they acquire a crescent shape. Such sandy hills are called dunes.
The height of the dunes, depending on the amount of sand and the strength of the wind, reaches from 20-30 m to 50-100 m. The wind, blowing sand grains from the slopes, shifts them towards the slope. Due to this, they are constantly moving forward.
Large dunes, moving from 1 m to 20 m a year, gradually change the terrain, and small dunes move up to 2-3 m per day during a strong storm. Moving dunes cover forests, gardens, fields, settlements.
Sandy hills in the desert are called dunes (Fig. 44). If the dunes are formed by the accumulation of sand brought by the waters of the oceans, seas and rivers, then the dunes arise from the sand during the weathering of local rocks. In our country, dunes are common in the Northern Aral Sea region, in the Kyzylkum, the Caspian lowland, and in the Southern Balkhash region. The height of dunes usually reaches 15-20 m, and in the largest deserts of the globe - the Sahara, Central Asia, Australia - up to 100-120 m.

Rice. 44. Dunes.

The dunes, like the dunes, are moved by the wind. Small dunes move up to 100-200 m per year, and large ones - up to 30-40 m per year. In most cases, the person himself contributes to the movement of sand. Sandy hills turn into wandering sands as a result of deforestation, overgrazing on pastures.
To stop the movement of dunes and dunes, drought-resistant shrubs and plants are planted on their gentle slopes. Trees are planted in the hollows between the hills.

1. What is called the plains? What types of plains exist?

2. How do the plains differ in height?

3. On the physical map, find all the plains named in the text.

4. If your area is flat, describe the topography of the land. By height and topography, determine what type of plains it belongs to. Learn from adults how your area is used for economic purposes?

5. What forces and how do they affect the change in the relief of the plains? Justify your answer with specific examples.

6. Why can't running water wash away slope soil with vegetation?

7*. In what parts of the territory of Kazakhstan is sandy relief common and why?