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 - their absolute height is 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).
By general character the surfaces of the plain 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 appeared, 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, receiving sufficient moisture, is dissected by river valleys, dotted complex systems beams and.
Study of the origin of the plains and modern forms their surface is of great economic importance, since the plains are densely populated and developed by man. There are many settlements on them, a dense network of communication lines, large lands. Therefore, it is precisely with the plains that one has to deal with when developing new territories, designing the construction of settlements, communication lines, industrial enterprises. As a result of human activities, the relief of the plains can change significantly: ravines are filled up, embankments are built, during mining open way quarries are formed, and near the mines hills created by man from waste rock - waste heaps grow.
The change in the relief of the ocean plains is affected by:
- , eruptions , faults earth's crust. The irregularities they create are transformed 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
There are several tectonic zones that differ in character rocks and violation of their occurrence:
I. Ciscaucasia with slightly hilly and flat relief. From the lower reaches of the Kuban to the lower reaches of the Terek passes the border between Ciscaucasia and the Greater Caucasus. This is a trough of a synclinal structure; in the western part it was called the Indolo-Kubansky, in the eastern part - the Terek-Caspian.
II. The Greater Caucasus is a meganticlinorium. The structure alternates between anticlinoria and synclinoria. There is an axial belt, a belt of the northern slope, a belt of the southern slope.
III. The Transcaucasian gently folded zone covers the Rionskaya and Kura depressions - gently folded structures with domes. Slightly hilly relief.
IV. The anticlinorium of the Lesser Caucasus is mountainous folded structures bordering the Armenian Highlands from the north and east.
V. Armenian folded zone - anticlinal and synclinal structures of sublatitudinal strike.
Within Ciscaucasia, the Kuban-Priazovsky lowland stands out, the mountains of the Mineralnye Vody group (up to 1400 m.) - in the center, and the Tersko-Kuma lowland in the east.
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Block #1 AFRICA
PRACTICAL WORK №1 "OROGRAPHIC OBJECTS OF AFIKA"
Run contour map(Grade 7) "Orographic objects of Africa" - designate the main landforms, according to the given nomenclature. According to the atlas of the 7th class, apply a scale of heights and paint over the contour map in accordance with the indicated relief forms.
Peninsulas, capes
1. Ras Engela (El Abyad). The northernmost point of the mainland (37021′ N, 9045′ E).
2. Green Cape (Almadi). The westernmost point of Africa (14045′ N, 17032′ W).
3. Good Hope Cape . In 1488, the Portuguese navigator V. Dias reached this cape on his way to India and named it Cape of Storms: storms from the Atlantic and Indian oceans met here. But the king of Portugal did not approve this harsh and true name, fearing a disadvantageous impression that would harm the colonial enterprises, and gave the name Cape of Good Hope hope to reach India. Located in the extreme south of Africa.
4. Igolny, cape. It was named by Portuguese navigators who noticed a magnetic anomaly near it - the deviation of the compass needle (needle). The southernmost point of the mainland (34052′ S, 19059′ E).
5. Somalia, peninsula. "Dark, black" according to the skin color of the population.
6. Ras Hafun, cape. The easternmost point of Africa (10026′ N, 51023′ E).
Mountain systems, highlands, uplands
Atlas Mountains:
1. High Atlas .
2. Toubkal (4165 m). The highest point of the Atlas Mountains.
Highlands, uplands:
What landforms dominate the African continent? Why?
Ahaggar. Highlands in the Sahara (highest point 2918 m).
2. Tibesti. Highlands in the Sahara.
3. Emi-Kushi (Emi-Usi) (3415 m). The highest point of the Tibesti highlands.
4. Cameroon, volcano (4070 m). It is located near the coast of the Gulf of Guinea.
5. South Guinean plateau . Located in the west of the Congo Basin.
6. Ethiopian (Abyssinian) highlands.
7. Ras Dashen (4620 m). The highest point of the Ethiopian highlands.
8. East African Highlands .
9. Kilimanjaro (5895 m), volcano . The highest peak in Africa.
10. Kenya (5199 m). Located in East Africa.
11. Karishimbi (4507 m) . One of the volcanoes of the Virunga massif.
12. dragon mountains . Located in South Africa, heights up to 3482 m.
13. cape mountains . Mountains in southern Africa, heights 2325 m.
Lowlands, plains, plateaus
1. high plateaus . Plateau between the Middle Atlas and Saharan Atlas and Anti-Atlas ranges.
2. Algiers-Tunisian lowland .
3. Libyan lowland .
4. Kattara (-133 m), depression. The lowest point in Africa, is located within the Libyan lowland.
5. Senegal-Mauritanian lowland .
6. Guinean lowland .
7. mozambican lowland .
8. Somali lowlands.
9. Darfur, plateau . It is located to the east of the basin of Lake Chad. Altitudes up to 3088 m (Marra).
10. Sahel. Plateau in the western Sahara.
11. Chad, plain . In its central part is Lake Chad.
12. Bodele, basin . The lowest part of the plain of Chad.
13. Kalahari, plain . Located in South Africa.
12Next ⇒
The relief of Africa is dominated by plains. This is due to the platform, which is the basis of almost the entire mainland.
What forms of relief prevail on the mainland of the West Siberian Plain Urgently!!!
A feature of the African plains is that high plains dominate among them - hills, plateaus, plateaus. On those parts of the platform, in the geological past they rose, high plateaus lie, On those that fell - depressions. It is interesting that even those parts of the platform sank (for example, the territory of the Sahara Desert) and where lowlands initially formed, now there are high plains exceeding 200 m. This is due to the general uplift of the entire territory of Africa in the Cenozoic. The lowlands stretched only in narrow strips along the sea coasts. Also, the mountains in Africa do not occupy at all large areas. In total, according to the height above sea level, the mainland is divided into two parts: Low Africa and High Africa.
The relief of Low Africa, covering the northern and western parts of the mainland, has heights of up to 1000 m. Large plains are located in this part. Their surface is very heterogeneous: uplands alternate with lowlands and plateaus. In those places where the crystalline rocks of the foundation (shields) come to the surface, among the sands of the Sahara, the highlands of Ahaggari Tibesti rise with heights of 3,000 m or more. Among the high plateaus up to 1000 m high lies the relatively low marshy depression of the Congo, which has a concave surface. In the northwest of the mainland rise the Atlas gpash, which formed at the junction of two lithospheric plates where the earth's crust was crumpled into folds.
The heights of High Africa, Covering the eastern and southern parts of the mainland, exceed 1000 m. The East African Plateau has the highest elevations - a huge, elevated plain. There are extinct volcanoes Kenya (5199 m) Kilimanjaro (5895 m). These volcanic mountains are confined to the East African Rift Zone. The Ethiopian highlands are also a highly elevated (2,000 - 3,000 m) large plain dotted extinct volcanoes. It ends abruptly in the east and descends in a staircase in the west. The Kalahari depression is surrounded on all sides by plateaus and plateaus. Mountains rise in the south of the mainland. The Cape Mountains are low and flat-topped. The Dragon Mountains are higher, from the coast by giant stairs they descend to the hinterland of the mainland.
Briefly all the landforms of Africa
Plains (height from 200 to 1000 m);
Lowlands;
Plateaus (East African Plateau);
Hollows (Chad, Kalahari);
The largest fault in the earth's crust on land;
Mountains (Atlas, Cape Mountains, Dragon Mountains);
Highlands (Ethiopian Highlands);
Volcanoes (Kilimanjaro, 5895 m. highest point).
Africa is located on one African plate. The African plate is moving to the northeast, colliding with the Eurasian plate. The consequence of this collision is the formation of the young Atlas Mountains in northern Africa. Further collision of plates will lead in the future, most likely, to the disappearance of the Mediterranean Sea and the transformation of Africa and Eurasia into a single continent. At the same time, in the area of the Red Sea, the processes of its expansion and the formation of a new oceanic crust are observed. In the future, the Red Sea will become a new ocean. However, the African plate itself is not completely stable. On its surface, the processes of breaking into two parts are clearly visible - in the area of the Great African Rifts in the southeast of the continent. On the territory of the faults is now fixed a large number of earthquakes and volcanic eruptions. Within 10 million years, a fault comparable to the Red Sea will form in the Ethiopian highlands.
Landforms of Africa
Part of the tectonic faults is now filled with water - first of all, these are lakes Nyasa and Tanganyika, as well as many other lakes in the region.
Africa is located on a single African platform, formed in the Archean period. In the south of the mainland, the old Cape and Dragon Mountains are located, significantly destroyed, in contrast to the Atlas continuing its formation. In general, two main regions can be distinguished in Africa: the North-Western plains and the South-Eastern - mountainous. The average height of the mainland is 750 meters. The plateaus occupy very large areas, while the lowlands are very few. The lowest point of the mainland is Lake Assal, the height of its depression is 157 meters above sea level. The highest point is Mount Kilimanjaro at 5895 meters.
Volcanoes and earthquakes are fairly common phenomena in Africa. In addition to Kilimanjaro, there are volcanoes such as Karisimbi (4507 m) and Cameroon (4100 m) (pictured). Earthquakes occur both in the north of Africa, where the border with the Euro-Asian lithospheric plate passes, and in the east of the mainland - in the area of tectonic faults and the Red Sea.
Africa is known for its richest deposits of diamonds (South Africa, Zimbabwe) and gold (South Africa, Ghana, Mali, Republic of the Congo). There are oil fields in Algeria, Libya, on the shelf of the Gulf of Guinea - in Nigeria. bauxite is mined in Guinea and Ghana. The resources of phosphorites, as well as manganese, iron and lead-zinc ores are concentrated in the zone north coast Africa. Large reserves of copper ores are concentrated in Zambia.
Features of the relief of Africa wikipedia
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Dragon Mountains in southeast Africa, mainly in South Africa, part of the Great Escarpment. . It is almost a monolithic basalt wall almost 250 km long. The height of some peaks in this chain exceeds 3300 m above sea level. In particular, the highest point - Mount Tkabana-Ntlenyana reaches a height of 3482 m. The mountains got their fabulous name because of the haze that hides the tops of the mountains. It is very similar to the puffs of smoke emitted from the dragon's nostrils. The beauty of these wonderful mountains is also truly fabulous. In winter, they are covered with snow, despite the proximity of the ever-warm indian ocean! And in summer, surrounded by greenery (the slopes of the Dragon Mountains are covered with boundless forests consisting of rare tree species), they conquer with their monumentality.
The mythical magic of the Dragon Mountains amazes everyone with the abundance of charming landscapes and dedicates to the hidden secrets of a rich history. Travelers will see beautiful landscapes with waterfalls and canyons, cliffs and valleys, evoking a touch of untouched nature. Especially beautiful is the Drakensberg mountain range called Amphitheatre, because of its flat top. ancient name Dragon Mountains "Ukutlamba", which means "palisade of spears".
What landforms prevail on the mainland Mount Atlas
According to Zulu legends, a mysterious monster lives here. There are no authentic facts about this, but who really lives in these magical mountains is antelopes, baboons, many small predators, as well as a variety of rare birds. Pure mountain lakes are literally teeming with fish - the most delicious of which is trout.
However, a purely natural attraction - the Drakensberg - is also considered to be a real historical complex. People (Bushmen) have inhabited these highlands since time immemorial, as evidenced by numerous drawings left on the rocky slopes of the Drakensberg. Especially a lot of them in the reserve "Giants Castle", listed in the book "World Heritage".
That is why mountain-building processes on the mainland are very poorly developed - young mountains grow only in the north of the continent.
Highlands and plateaus of Africa
More than 4/5 of Africa is occupied by plateaus. Lowlands on the mainland are virtually absent.
What landforms are predominant in Africa? Why?
Not only the mainland is located on the African-Arabian platform, but also Madagascar, the Seychelles and the Arabian Peninsula.
The African Highlands are located in the southeastern part of the mainland. The average heights here exceed 1000 m above sea level. In this region, the African-Arabian platform rises somewhat.
The Ethiopian highlands are located in southeastern Africa. This part of the mainland is called High Africa, it is here that highest peak continent - Mount Kilimanjaro.
These areas are characterized by frequent earthquakes, which provoke the eruptions of the Karisimbi and Cameroon volcanoes. Highlands are also found in the Sahara desert, the highest of them being the Tibesti and Ahaggar highlands.
Mountains of Africa
On the coast of the Indian Ocean are the Cape and Dragon Mountains - their height decreases towards the center of the mainland. The Cape Mountains formed during the Upper Paleozoic.
The region of the Cape Mountains is characterized by a Mediterranean type of climate. Cape Mountains - a prime example revived mountains that were formed on the ancient destroyed mountain systems and inherited from them a folded structure that can be traced in the modern relief.
The highest peak of the Cape Mountains is Mount Compasberg, whose height reaches 2500 m. In the north of the mainland, as a result of the displacement of the spirit of the lithospheric plates, young Atlas Mountains were formed.
These mountains are a continuation of the young mountains of Europe, which are located in the Gibraltar region. The length of the mountain ranges of the Atlas Mountains is 2500 km: they originate in the north of Morocco and stretch to Tunisia.
The highest peak of the Atlas Mountains is Mount Toubkal (4100m). Due to tectonic faults, earthquakes often occur in the Atlas Mountains region.
Lowlands of Africa
The lowlands of Africa occupy only 9% of its territory. The lowest point of the continent is the salt lake Assal, which is located on the territory of the state of Djibouti (Red Sea coast). Lowlands are also common in some countries of Central Africa.
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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 and 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 dismemberment by river valleys, gullies and ravines: what
the higher the plain, 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.
The different appearance of the 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 14-A-1-1). 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 plinth comes to the surface - folds cut off 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 - more
hard 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 that experience stable uplift only in the neotectonic stage of development are composed of layers sedimentary rocks large thickness (hundreds of meters and a few kilometers) - limestone, dolomite, sandstone, siltstone, etc. Over millions of years, the sediments hardened, became rocky and acquired resistance to erosion. 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 them. appearance due to morphosculpture (East European, southern part of West Siberian, etc.).
Since the stratal 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, Leno-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 by the valleys of many rivers flowing down from the mountains and complicated by their alluvial fans. They are difficult
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 southern mountains during 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, Timansky, 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 1 .
Plains on land form two latitudinal series corresponding to the platforms of Laurasia and Gondwana. Northern range of plains formed within relatively stable limits modern times the ancient North American and East European platforms and the young epipaleozoic West Siberian platform - a plate that has experienced even a slight subsidence and is predominantly a low-lying plain expressed in relief.
The Central Siberian Plateau, and in the morphological and structural sense, these are high plains - a plateau, formed on the site of the ancient Siberian platform, activated in modern 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.
Peculiar orographic and structural feature plains of the northern row: beyond the North
“Often, plateaus and plateaus are distinguished only by their appearance and degree of dissection, without taking into account their geological structure. Plateaus are considered less dissected landforms and are classified as high plains. Plateaus are usually higher, dissected in the marginal parts more intensely and deeper, therefore they are referred to as mountains.
the Arctic Circle is dominated by low coastal accumulative plains; 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, Vilyuyskaya.
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 Gondvan 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, stratal and accumulative plains were formed (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
into large ones and give them a peculiar appearance. They will be discussed below.
Table 14
Areas of the main types of continent morphostructures (%)
Peculiarities geographical location Western Siberia
Remark 1
To the east of the Ural Mountains lie vast expanses of the Asian part of Russia. This territory has long been called Siberia. But due to the variety tectonic structure This territory was divided into several separate regions. One of them is Western Siberia.
The basis of Western Siberia is the West Siberian Plain. It's bounded in the west Ural mountains, and in the east - the Yenisei River. In the north, the plain is washed by the waters of the seas of the Arctic Ocean. Southern borders approach the Kazakh uplands and the Turgai plateau. total area plains is about $3$ million km$²$.
The characteristic features of the West Siberian Plain are the following features:
- insignificant fluctuation of heights in such a vast territory;
- the length from north to south and an almost flat relief led to a clear change in natural zones with latitude (classical latitudinal zonality);
- formation of the largest swamp areas in the taiga and salt accumulation landscapes in the steppe zone;
- a transitional climate is formed from the temperate continental of the Russian Plain to the sharply continental of Central Siberia.
The history of the formation of the plain
The West Siberian Lowland lies on the Upper Paleozoic Plate. Sometimes this tectonic structure is also called epihercynian. The crystalline basement of the slab contains metamorphosed rocks. The foundation sinks towards the center of the slab. The total thickness of the sedimentary cover exceeds $4$ km (up to $6-7$ km in some areas).
As already mentioned, the foundation of the slab was formed as a result of the Hercynian orogeny. Further there was a peneplenization (leveling of a relief by means of erosive processes) of the ancient mountainous country. In the Paleozoic and Mesozoic, troughs form in the center, and the foundation was flooded by the sea. Therefore, it is covered with a significant thickness of Mesozoic deposits.
Later, during the era of the Caledonian folding, southeastern part the plains rose from the bottom of the sea. In the Triassic and Jurassic, the processes of relief denudation and the formation of a sedimentary rock mass predominated. Sedimentation continued into the Cenozoic. During the Ice Age, the north of the plain was under the thickness of the glacier. After its melting, a significant area of Western Siberia was covered with moraine deposits.
Characteristics of the relief of Western Siberia
As already noted, geological history led to the formation of a flat relief on the territory of the West Siberian Plain. But a more detailed study of the physical and geographical features of the region showed that the orography of the territory is complex and diverse.
Large relief elements on the territory of the plain are:
- lowlands;
- sloping plains;
- hills;
- plateau.
In general, the West Siberian Plain has the form of an amphitheater, open to the North Arctic Ocean. Plateau and upland areas predominate in the western, southern and eastern periphery. Lowlands prevail in the central regions and in the north. The lowlands are represented by:
- Kandinsky;
- Nizhneobskaya;
- Nadymskaya;
- Purskoy.
Among the plateau, the Ob plateau stands out. And the elevations are presented:
- Severo-Sosvinskaya;
- Turin;
- Ishimskaya;
- Chulym-Yenisei and others.
In the relief, there are zones of glacial-marine and permafrost-solifluction processes (tundra and northern taiga), fluvioglacial forms of lacustrine-glacial plains (up to the middle taiga), and a zone of semiarid structural-denudation plateaus with erosion processes.
Remark 2
Currently, human economic activity plays an important relief-forming role. The development of Western Siberia is accompanied by the development of minerals. This causes changes in the structure of rock layers and changes the course of physical and geographical processes. erosion processes are intensifying. In the south during development Agriculture a large amount of minerals are introduced into the soil. Chemical erosion develops. It is necessary to take a balanced approach to the development of the nature of Siberia.
It is characterized by a predominantly flat landscape, prevailing over the mountain landscape, not only on land, but also under water.
What are plains?
Plains are relatively flat, vast areas in which the heights of neighboring areas fluctuate within 200 m, they have a slight slope (no more than 5 m). The most illustrative example of a classical plain is the West Siberian Lowland: it has an exceptionally flat surface, on which the elevation difference is almost imperceptible.
Relief features
As we already understood from the above definition, plains are terrain with a flat and almost even relief, without noticeable ups and downs, or hilly, with a smooth alternation of surface elevations and depressions.
Flat plains are mostly insignificant in size. They are located near the seas and big rivers. Hilly plains with uneven terrain are more common. For example, the relief of the East European (Russian) Plain is characterized by the presence of both hills over 300 meters high and depressions, whose height is below sea level (Caspian lowland). Other famous plains of the world are Amazonian, Mississippi. They have a similar topography.
Plains Features
A distinctive feature of all plains is a clearly defined, clearly defined visible line horizon, which can be straight or undulating, which is determined by the relief of a particular area.
People from ancient times preferred to create settlements on the plains. Since these places are rich in forests and fertile soil. Therefore, today the plains are still the most densely populated. Most of the minerals are mined in the plains.
Considering that the plains are an area with a huge area and a large extent, they are characterized by a variety of natural areas. So, on the East European Plain there are territories with mixed and deciduous forests, tundra and taiga, steppe and semi-desert. The plains of Australia are represented by savannas, and the Amazonian lowland by selva.
Climatic features
The climate of the plain is a fairly broad concept, since it is determined by many factors. These are geographical location, climatic zone, area of the region, length, relative proximity to the ocean. In general, the flat terrain is characterized by a clear change of seasons due to the movement of cyclones. Often on their territory there is an abundance of rivers and lakes, which also affect climatic conditions. Some plains have their vast area consisting of the continuous desert of the Western Plateau of Australia).
Plains and mountains: what is their difference
Unlike plains, mountains are tracts of land that rise sharply above the adjacent surface. They are characterized by significant fluctuations in heights and large slopes of the relief. But small areas flat terrain are also found in the mountains, between mountain ranges. They are called intermountain basins.
Plains and mountains are landforms whose differences are based on their origin. Most of the mountains were formed under the influence of tectonic processes, the movement of layers that occurs deep in the earth's crust. In turn, the plains lie mainly on platforms - stable areas of the earth's crust, they were influenced by the external forces of the Earth.
Among the differences between mountains and plains, in addition to appearance and origin can be distinguished:
- maximum height (in the plains it reaches 500 m, in the mountains - over 8 km);
- area (the area of mountains on the entire surface of the Earth is significantly inferior to the area of plains);
- the probability of earthquakes (on the plains it is practically zero);
- degree of development;
- ways of human use.
major plains
located in South America, is the largest in the world, its area is about 5.2 million square meters. km. It has a low population density. It is characterized by a hot and humid climate, dense tropical forests, occupying vast areas and teeming with animals, birds, insects and amphibians. Many animal species of the Amazonian lowland are not found anywhere else.
The East European (Russian) Plain is located in the eastern part of Europe, its area is 3.9 million square kilometers. km. Most of the plains are in Russia. It has a gently sloping relief. The bulk of large cities are located here, as well as a significant share of the country's natural wealth.
Located in Eastern Siberia. Its area is about 3.5 million square meters. km. A feature of the plateau is the alternation of mountain ranges and wide plateaus, as well as the frequent permafrost, the depth of which reaches 1.5 km. The climate is sharply continental, the vegetation is dominated by deciduous forests. The plain is rich in minerals and has an extensive river basin.