Yakut folk song as a genre of folklore. Yakut folk art

Western Siberian Plain(it won’t be difficult to find it on a world map) - one of the largest in Eurasia. It stretches for 2500 km from the harsh shores of the Arctic Ocean to the semi-desert territories of Kazakhstan and for 1500 km - from Ural mountains and to the mighty Yenisei. This entire area consists of two cup-shaped flat depressions and many wetlands. Between these depressions stretch the Siberian Ridges, which rise 180-200 meters.

The West Siberian Plain is a rather interesting and fascinating point that deserves detailed consideration. The natural object located almost equidistant between the Atlantic and the continental center of the mainland. About 2.5 million sq. km covers the area of ​​this huge plain. This distance is very impressive.

Climatic conditions

Geographical position The West Siberian Plain on the mainland creates interesting climatic conditions. Therefore, the weather in most of the plain is temperate continental. Large Arctic masses enter this territory from the north, bringing with them intense cold in winter, and in summer the thermometer shows from + 5 °C to + 20 °C. In January, on the southern and northern sides the temperature can vary from -15 °C to -30 °C. The lowest winter indicator was recorded in the northeast of Siberia - down to -45 °C.

Humidity on the plain also spreads gradually from south to north. With the beginning of summer, most of it falls on the steppe zone. In mid-summer, in July, the heat takes over the entire south of the plain, and the humid front moves to the north, thunderstorms and showers sweep over the taiga. At the end of August, the rains reach the tundra zone.

Water streams

When describing the geographical location of the West Siberian Plain, it is necessary to talk about the water system. A huge number of rivers flow through this territory, and there are also numerous lakes and swamps. The largest and deepest river is the Ob with its tributary Irtysh. It is not only the largest this region, but also one of the greatest in the world. In terms of its area and length, the Ob dominates among the rivers of Russia. The Pur, Nadym, Tobol and Taz water streams suitable for navigation also flow here.

The plain holds the world record for the number of swamps. Such a vast territory cannot be found on the globe. The swamps cover an area of ​​800 thousand square meters. km. There are several reasons for their formation: excessive moisture, flat surface of the plain, a large number of peat, as well as low air temperature.

Minerals

This region is rich in mineral resources. This is largely influenced by the geographical location of the West Siberian Plain. Here, in huge quantities oil and gas deposits are concentrated. Its vast wetland areas contain a large reserve of peat - approximately 60% of the total amount in Russia. There are iron ore deposits. Siberia is also rich in its hot waters, which contain salts of carbonates, chlorides, bromine and iodine.

Animal and plant worlds

The climate of the plain is such that the flora here is quite poor compared to neighboring regions. This is especially noticeable in the taiga and tundra zones. The reason for such poverty of plants is long-term glaciation, which does not allow plants to spread.

The fauna of the plain is also not very rich, despite the enormous extent of the territories. The geographical position of the West Siberian Plain is such that it is almost impossible to meet interesting individuals here. There are no unique animals living only in this territory. All species that live here are common to other regions, both neighboring and the entire continent of Eurasia.

WEST SIBERIAN PLAIN (West Siberian Lowland), one of the largest plains globe. Located in the northern part of Asia, in Russia and Kazakhstan. The area is over 3 million km2, including 2.6 million km2 in Russia. The length from west to east is from 900 km (in the north) to 2000 (in the south), from north to south up to 2500 km. In the north it is washed by the Arctic Ocean; in the west it borders with the Urals, in the south - with the Turgai plateau and the Kazakh small hills, in the southeast - with the mountains of Southern Siberia, in the east - along the valley of the Yenisei River with the Central Siberian Plateau.

Relief. It is a low accumulative plain with a rather uniform topography, various forms of permafrost (extended up to 59° north latitude), increased swampiness and ancient and modern salt accumulation developed in the south in loose rocks and soils. The predominant heights are about 150 m. In the north, in the area of ​​distribution of marine accumulative and moraine plains, the general flatness of the territory is broken by moraine gently ridged and hilly-ridged (North-Sosvinskaya, Lyulimvor, Verkhne-, Srednetazovskaya, etc.) hills with a height of 200-300 m, the southern border of which runs around 61-62° north latitude; they are covered in a horseshoe shape from the south by the flat-topped heights of the Belogorsk Continent, Sibirskie Uvaly, etc. In the northern part, exogenous permafrost processes (thermoerosion, soil heaving, solifluction) are widespread, deflation occurs on sandy surfaces, and peat accumulation occurs in swamps. There are numerous ravines on the plains of the Yamal and Gydansky peninsulas and on the moraine hills. To the south, the area of ​​moraine relief is adjacent to flat lacustrine-alluvial lowlands, the lowest (height 40-80 m) and swampy of which are Kondinskaya and Sredneobskaya. The area not covered by Quaternary glaciation (south of the line Ivdel - Ishim - Novosibirsk - Tomsk - Krasnoyarsk) is a weakly dissected denudation plain, rising (up to 250 m) towards the Urals. In the interfluve of the Tobol and Irtysh there is an inclined, in places with ragged ridges, lacustrine-alluvial Ishim Plain (120-220 m) with a thin cover of loess-like loams and loess overlying salt-bearing clays. It is adjacent to the alluvial Barabinskaya Lowland and the Kulunda Plain, where the processes of deflation and modern salt accumulation develop. In the foothills of Altai there are ridge-hilly Priobskoe plateau (height up to 317 m - highest point West Siberian Plain) and Chulym Plain. ABOUT geological structure and minerals, see the article West Siberian Platform, with which the West Siberian Plain is geostructurally connected.

Climate. Continental climate prevails. Winter in polar latitudes is severe and lasts up to 8 months (the polar night lasts almost 3 months), average January temperatures range from -23 to -30 °C; in the central part, winter lasts up to 7 months, average January temperatures range from -20 to -22 °C; in the south, where the influence of the Asian anticyclone increases, at the same temperatures winter is shorter (up to 5-6 months). Minimum air temperature -56 °C. In summer, the westerly transport of Atlantic air masses predominates with invasions of cold air from the Arctic in the north, and dry warm air masses from Kazakhstan and Central Asia in the south. In the north, summer is short, cool and humid with polar days, in the central part it is moderately warm and humid, in the south it is arid and dry, with hot winds and dust storms. The average July temperature increases from 5 °C in the Far North to 21-22 °C in the south. The duration of the growing season in the south is 175-180 days. Atmospheric precipitation falls mainly in summer. The wettest (400-550 mm per year) are the Kondinskaya and Middle Ob lowlands. To the north and south, annual precipitation gradually decreases to 250 mm.

Surface waters. On the West Siberian Plain there are more than 2000 rivers belonging to the Arctic Ocean basin. Their total flow is about 1200 km 3 of water per year; up to 80% of the annual runoff occurs in spring and summer. The largest rivers are the Ob, Yenisei, Irtysh, Taz and their tributaries. The rivers are fed by mixed water (snow and rain), the spring flood is extended, and the low water period is long in summer, autumn and winter. Ice cover on rivers lasts up to 8 months in the north, and up to 5 in the south. Large rivers are navigable, are important rafting and transport routes, and, in addition, have large reserves of hydropower resources. The total area of ​​the lakes is more than 100 thousand km2. The largest lakes are located in the south - Chany, Ubinskoye, Kulundinskoye. In the north there are lakes of thermokarst and moraine-glacial origin. In the suffusion depressions there are many small lakes (less than 1 km2): in the Tobol-Irtysh interfluve - more than 1500, in the Barabinskaya Lowland - 2500, including fresh, salty and bitter-salty; There are self-sedating lakes.

Types of landscapes. The uniformity of the relief of the vast West Siberian Plain determines a clearly defined latitudinal zonation of the landscapes, although compared to the East European Plain, the natural zones here are shifted to the north. On the Yamal, Tazovsky and Gydansky peninsulas, under conditions of continuous permafrost, landscapes of arctic and subarctic tundra were formed with moss, lichen and shrub (dwarf birch, willow, alder) cover on gley soils, peat gley soils, peat podburs and turf soils. Polygonal mineral grass-hypnum bogs are widespread. The share of indigenous landscapes is extremely small. To the south, tundra landscapes and swamps (mostly flat-hilly) are combined with larch and spruce-larch woodlands on podzolic-gley and peat-podzolic-gley soils, forming a narrow zone of forest-tundra, transitional to the forest (forest-swamp) zone of the temperate zone, represented by the subzones northern, middle and southern taiga. What is common to all subzones is swampiness: over 50% of the northern taiga, about 70% - middle, about 50% - southern. The northern taiga is characterized by flat and large-hilly raised bogs, the middle one - ridge-hollow and ridge-lake bogs, the southern one - hollow-ridge, pine-shrub-sphagnum, transitional sedge-sphagnum and lowland tree-sedge. The largest swamp massif is the Vasyugan Plain. Forest complexes of different subzones are unique, formed on slopes with varying degrees of drainage. Northern taiga forest complexes on permafrost are represented by sparse and low-growing pine, pine-spruce and spruce-fir forests on gley-podzolic and podzolic-gley soils. Indigenous landscapes of the northern taiga occupy 11% of the area of ​​the West Siberian Plain. Common to the forest landscapes of the middle and southern taiga is the wide distribution of lichen and shrub-sphagnum pine forests on sandy and sandy loamy ferruginous and illuvial-humus podzols. On loamy soils in the middle taiga there are spruce-cedar forests with larch and birch forests on podzolic, podzolic-gley, peat-podzolic-gley and gley peat-podzols. In the subzone of the southern taiga on loams there are spruce-fir small-grass forests and birch forests with aspen on sod-podzolic and sod-podzolic-gley soils (including with a second humus horizon) and peat-podzolic-gley soils. Indigenous landscapes in the middle taiga occupy 6% of the area of ​​the West Siberian Plain, in the southern - 4%. The subtaiga zone is represented by parkland pine, birch and birch-aspen forests on gray, gray gley and soddy-podzolic soils (including with a second humus horizon) in combination with steppe meadows on cryptogleyed chernozems, sometimes solonetzic. Indigenous forest and meadow landscapes have practically not been preserved. Swampy forests turn into lowland sedge-hypnum (with ryams) and sedge-reed bogs (about 40% of the zone's territory). For forest-steppe landscapes of sloping plains with loess-like and loess-like covers on salt-bearing tertiary clays, birch and aspen-birch groves on gray soils and malts in combination with forb-grass steppe meadows on leached and cryptogleyed chernozems are typical, to the south - with meadow steppes on ordinary chernozems , in some places solonetzic and solonchakous. On the sands - pine forests. Up to 20% of the zone is occupied by eutrophic reed-sedge bogs. In the steppe zone, indigenous landscapes have not been preserved; in the past these were forb-feather grass steppe meadows on ordinary and southern chernozems, sometimes saline, and in the drier southern regions - fescue-feather grass steppes on chestnut and cryptogley soils, gley solonetzes and solonchaks.

Environmental problems and protected natural areas. In oil production areas, due to pipeline breaks, water and soil are polluted with oil and petroleum products. In forestry areas there are overcuttings, waterlogging, the spread of silkworms, and fires. In agricultural landscapes there is an acute problem of lack of fresh water, secondary salinization of soils, destruction of soil structure and loss of soil fertility during plowing, drought and dust storms. In the north, there is degradation of reindeer pastures, in particular due to overgrazing, which leads to a sharp reduction in their biodiversity. No less important is the problem of preserving hunting grounds and natural habitats of fauna.

To study and protect typical and rare natural landscapes, numerous reserves, national and natural parks. Among the largest reserves are: in the tundra - the Gydansky Reserve, in the northern taiga - the Verkhnetazovsky Reserve, in the middle taiga - the Yugansky Reserve, etc. A national park has been created in the subtaiga - Priishimskiye Bory. Natural parks have also been organized: in the tundra - Oleniy Ruchi, in the northern taiga - Numto, Sibirskie Uvaly, in the middle taiga - Kondinsky Lakes, in the forest-steppe - Bird Harbor.

Lit.: Trofimov V. T. Patterns of spatial variability of engineering-geological conditions of the West Siberian Plate. M., 1977; Gvozdetsky N. A., Mikhailov N. I. Physical geography of the USSR: Asian part. 4th ed. M., 1987; Soil cover and land resources Russian Federation. M., 2001.

The material contains information about the relief that is characteristic of the given territory. The article examines the processes that had a significant impact on the formation of the landscape of the West Siberian Plain. A table is provided that allows us to better understand the features of the formation of land cover throughout the entire existence of the plain region.

Relief of the West Siberian Plain

The plane is expressed by an extremely low accumulative plain with a uniform topography.

The main elements of the relief are wide, flat interfluves and river valleys.

It is characterized by various forms of permafrost and high swampiness. Also at the southern tip you can see both ancient and modern salt accumulations.

Rice. 1. Salt deposits.

In the north there is a general flatness. The homogeneous structure of the territory is disrupted by gently undulating and undulating hills with an average height of 200-300 m.

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The southern border consists of horseshoe-shaped hills with flat tops, including:

• Poluyskaya Upland;
• Belogorsk Continent;
• Tobolsk Continent;
• Siberian Uvaly.

On the peninsulas:

• Yamal;
• Tazovsky;
• Gydansky.

permafrost is observed.

Rice. 2. Yamal Peninsula.

The southern region has the character of a connecting territory, which includes flat lacustrine-alluvial lowlands. The lowest of them have a height of 40-80 m.

This territory is a weakly dissected denudation plain, rising up to 250 m to the west, to the foot of the Urals.

In the interfluve of the Tobol and Irtysh lies the lacustrine-alluvial and Ishim plain, which has a peculiarity - it is slightly inclined and has pronounced ribbed ridges. Alluvial lowlands adjoin this territory:

• Barabinskaya;
• Vasyugan Plain;
• Kulundinskaya plain.

"Living" earth

The tectonic structure of the West Siberian Plain is such that it includes a foundation and a cover. The plain plate is in constant motion.

The cuff of loose rocks “hides” underground rivers that carry both fresh and mineral-rich waters. There are hot springs with water temperatures ranging from 10 to 15°C.

Rice. 3. Underground river.

The West Siberian plate began its formation back in the Mesozoic era. During this period, the lands between the Urals and the Siberian platform “sank,” which led to the formation of a sedimentation basin.

Table "Relief of the West Siberian Plain"

What have we learned?

We found out what determines the specificity of relief formation on the territory of the West Siberian Plain. We received information about the depth of the frozen layer in this area of ​​land. We received information regarding the relief, which is typical for mountainous areas. Specified historical period formation of the West Siberian plate.

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West Siberian Plain

The West Siberian Lowland is one of the largest lowland accumulative plains on the globe. It is located to the north of the hilly plain of Kazakhstan and the Altai mountains, between the Urals in the west and the Central Siberian Plateau in the east. Extent from north to south up to 2500 km, from W. to E. from 1000 to 1900 km; area about 2.6 million. km 2. The surface is flat, slightly dissected, with small amplitudes of heights. The heights of the lowlands of the northern and central regions do not exceed 50-150 m, low elevations (up to 220-300 m) are characteristic mainly of the western, southern and eastern outskirts of the plain. The strip of hills also forms the so-called. Siberian Uvaly, extending in the middle part of the West-North. R. from the Ob almost to the Yenisei. Everywhere, wide, flat spaces of interfluves with slight surface slopes predominate, heavily swamped and in places complicated by moraine hills and ridges (in the north) or low sandy ridges (mainly in the south). Significant areas are occupied by flat ancient lake basins - woodlands. River valleys form a relatively sparse network and in the upper reaches most often appear as shallow hollows with poorly defined slopes. Only a few of the largest rivers flow in well-developed, deep (up to 50-80 m) valleys, with a steep right bank and a system of terraces on the left bank.

Z.-S. R. formed within the epi-Hercynian West Siberian plate, the foundation of which is composed of intensely dislocated Paleozoic sediments. They are covered everywhere with a cover of loose marine and continental Meso-Cenozoic rocks (clays, sandstones, marls, etc.) with a total thickness of over 1000 m(in foundation depressions up to 3000-4000 m). The youngest anthropogenic deposits in the south are alluvial and lacustrine, often covered with loess and loess-like loams; in the north - glacial, marine and glacial-marine (thickness in places up to 200 m). In the cover of loose sediments Z.-S. R. horizons are contained groundwater- fresh and mineralized (including brines), there are also hot (up to 100-150 ° C) waters (see West Siberian artesian basin). In the depths of Z.-S. R. concluded the richest industrial oil fields and natural gas(see West Siberian oil and gas basin).

The climate is continental and quite harsh. In winter, cold continental air masses of temperate latitudes predominate over the plain, and in the warm season, an area of ​​low pressure is formed and moist air masses from the North Atlantic often enter here. Average annual temperatures range from -10.5°C in the north to 1-2°C in the south, average temperatures in January range from -28 to -16°C, and in July from 4 to 22°C. The duration of the growing season in the extreme south reaches 175-180 days. The bulk of precipitation is brought by air masses from the west, mainly in July and August. Annual precipitation is from 200-250 mm in the tundra and steppe zones up to 500-600 mm in the forest area. Snow depth from 20-30 cm in the steppe up to 70-100 cm in the taiga of the Yenisei regions.

The plain territory is drained by more than 2000 rivers, the total length of which exceeds 250 thousand km. km. The largest of them are the Ob, Yenisei, and Irtysh. The main sources of river nutrition are melted snow waters and summer-autumn rains; up to 70-80% of the annual runoff occurs in spring and summer. There are many lakes, the largest are Chany, Ubinskoye, etc. Some of the lakes in the southern regions are filled with salty and bitter-salty water. Large rivers are important navigable and rafting routes connecting southern regions with the northern ones; The Yenisei, Ob, Irtysh, Tom also have large reserves of hydropower resources.

Flat relief of the W.-N. river. causes a clearly pronounced latitudinal geographical zoning. Specific feature most zones Western Siberia is excessive ground moisture and, as a consequence of this, the widespread occurrence of swampy landscapes, which in the south are replaced by solonetzes and solonchaks. The north of the plain is a tundra zone, in which landscapes of arctic, moss, and lichen tundra are formed on tundra arctic and tundra gley soils, and in the south - shrub tundra. To the south there is a narrow strip of forest-tundra, where complex landscape complexes of shrub tundra, spruce-larch woodlands, sphagnum and lowland bogs are developed on peaty-gley, gley-podzolic and bog soils. Most of W.-S. R. belongs to the forest (forest-swamp) zone, within which coniferous taiga, consisting of spruce, fir, cedar, pine, and Siberian larch, predominates on podzolic soils; Only in the extreme southern zone are taiga massifs replaced by a strip of small-leaved forests of birch and aspen. The total forest area exceeds 60 million hectares. ha, timber reserves 9 billion m 3, and its annual growth is 100 million. m 3. The forest zone is distinguished by the widespread development of raised ridge-hollow sphagnum bogs, which in some places account for more than 50% of the area. Typical animals of the forest zone are: brown bear, lynx, wolverine, marten, otter, weasel, sable, elk, Siberian roe deer, squirrel, chipmunk, muskrat and other representatives of the fauna of the European-Siberian subregion of the Palearctic.

To the south of the subzone of small-leaved forests there is a forest-steppe zone, where leached and ordinary chernozems, meadow-chernozems, dark gray forest and swamp soils, solonetzes, and malt soils are formed under the not yet plowed herb meadows, birch-aspen copses (“spikes”) and grassy bogs. . The extreme southern part of the W.-N. r. It occupies a steppe zone, in the north of which, until recently, grass-feather grasses of various types predominated, and in the south, feather-grass-fescue steppes predominated. Now these steppes with their fertile chernozem and dark chestnut soils have been plowed and only areas with saline soils have retained their virgin character.

Lit.: West Siberian Lowland. Essay on Nature, M., 1963; Western Siberia, M., 1963.

N. I. Mikhashov.

Big Soviet encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

See what the “West Siberian Plain” is in other dictionaries:

West Siberian Plain ... Wikipedia

Between the Urals in the west and the Central Siberian Plateau in the east. OK. 3 million km². The length from north to south is up to 2500 km, from west to east up to 1900 km. Height ranges from 50 to 150 m in the northern and central parts to 300 m in the western, southern and... ... Big Encyclopedic Dictionary

WEST SIBERIAN PLAIN, between the Urals in the west and the Central Siberian Plateau in the east. OK. 3 million km2. The length from north to south is up to 2500 km, from west to east up to 1900 km. Height from 50 to 150 m in the northern and central parts to 300 m in... ... Russian history

One of the largest on Earth. Occupies b. Part Zap. Siberia, stretching from the coast of the Kara Sea in the north to the Kazakh small hills in the south, from the Urals in the west to the Central Siberian Plateau in the east. OK. 3 million km². Wide flat or… Geographical encyclopedia

Between the Urals in the west and the Central Siberian Plateau in the east About 3 million km2. The length from north to south is up to 2500 km, from west to east up to 1900 km. Height from 50 to 150 m in the northern and central parts to 300 m in the western, southern and eastern parts.… … encyclopedic Dictionary

West Siberian Plain- West Siberian Plain, West Siberian Lowland. One of the largest low-lying accumulative plains in the world. It occupies most of Western Siberia, stretching from the coast of the Kara Sea in the north to the Kazakh small hills and ... Dictionary "Geography of Russia"

The West Siberian Plain is one of the largest accumulative lowland plains on the globe. It extends from the shores of the Kara Sea to the steppes of Kazakhstan and from the Urals in the west to the Central Siberian Plateau in the east. The plain has the shape of a trapezoid tapering to the north: the distance from its southern border to the northern reaches almost 2500 km, the width is from 800 to 1900 km, and the area is only slightly less than 3 million km 2.

The relief of the West Siberian Plain is one of the most homogeneous in the world. Occupying an area of ​​2.6 million km², the West Siberian Plain stretches from west to east, from the Urals to the Yenisei, for 1900 km, north to south, from the Arctic Ocean to Altai mountains, - at 2400 km. Only in the extreme south do altitudes exceed 200 m; the vast majority of the plain has an altitude of less than 100 m above sea level; Alluvial-lacustrine and accumulative relief predominates (also denudation in the south). Relief features characteristic of Western Siberia, such as vast floodplains and huge swamps, are especially common in the northern part of the plain; The relief north of the latitudinal section of the Ob River was formed under the influence of transgressions of the sea and glaciers.

In the northwest and northeast of the West Siberian Plain, the relief is accumulative glacial, formed by glaciers descending from the mountains of the Northern Urals and the Putorana Plateau. The valleys of large rivers are terraced. On the Yamal and Gydan peninsulas there are aeolian dunes. Relatively elevated and dry territories, where the bulk of the population of Western Siberia is concentrated, are located south of 55 ° C. Latitude.

The differentiated subsidence of the West Siberian Plate in the Mesozoic and Cenozoic led to the predominance within its boundaries of processes of accumulation of loose sediments, the thick cover of which levels out the surface irregularities of the Hercynian basement. Therefore, the modern West Siberian Plain has a generally flat surface. However, it cannot be considered as a monotonous lowland, as was recently believed. In general, the territory of Western Siberia has a concave shape. Its lowest sections (50-100 m) are located mainly in the central (Kondinskaya and Sredneobskaya lowlands) and northern (Nizhneobskaya, Nadymskaya and Purskaya lowlands) parts of the country. Along the western, southern and eastern outskirts stretch low (up to 200-250 m) hills: North Sosvinskaya, Turinskaya, Ishimskaya, Priobskoye and Chulym-Yenisei plateaus, Ketsko-Tymskaya, Verkhnetazovskaya, Nizhneeniseiskaya. A clearly defined strip of hills is formed in the inner part of the plain by the Siberian Uvals (average height - 140-150 m), stretching from the west from the Ob to the east to the Yenisei, and the Vasyugan Plain parallel to them.

Some orographic elements of the West Siberian Plain correspond to geological structures: gentle anticlinal uplifts correspond, for example, to the Verkhnetazovskaya and Lyulimvor hills, and the Barabinskaya and Kondinskaya lowlands are confined to syneclises of the base of the plate. However, in Western Siberia, discordant (inversion) morphostructures are also common. These include, for example, the Vasyugan Plain, which formed on the site of a gently sloping syneclise, and the Chulym-Yenisei Plateau, located in the zone of basement deflection.

The West Siberian Plain is usually divided into four large geomorphological regions: 1) marine accumulative plains in the north; 2) glacial and water-glacial plains; 3) periglacial, mainly lacustrine-alluvial plains; 4) southern non-glacial plains (Voskresensky, 1962).
The differences in the relief of these areas are explained by the history of their formation in Quaternary times, the nature and intensity of recent tectonic movements, and zonal differences in modern exogenous processes. In the tundra zone, relief forms are especially widely represented, the formation of which is associated with the harsh climate and widespread permafrost. Thermokarst depressions, bulgunnyakhs, spotted and polygonal tundras are very common, and solifluction processes are developed. Typical of the southern steppe provinces are numerous closed basins of suffusion origin, occupied by salt marshes and lakes; The network of river valleys here is sparse, and erosional landforms in the interfluves are rare.

The main elements of the relief of the West Siberian Plain are wide, flat interfluves and river valleys. Due to the fact that the interfluve spaces account for most of area of ​​the country, they determine the general appearance of the plain's topography. In many places, the slopes of their surfaces are insignificant, the flow of precipitation, especially in the forest-swamp zone, is very difficult and the interfluves are heavily swamped. Large areas are occupied by swamps north of the Siberian line railway, on the interfluves of the Ob and Irtysh, in Vasyugan and Barabinsk forest-steppe.

However, in some places the relief of the interfluves takes on the character of a wavy or hilly plain. Such areas are especially typical of some northern provinces of the plain, which were subject to Quaternary glaciations, which left here piles of stadial and bottom moraines. In the south - in Baraba, on the Ishim and Kulunda plains - the surface is often complicated by numerous low ridges stretching from northeast to southwest.

Western Siberia. Photo: Bernt Rostad

Another important element The country's topography is river valleys. All of them were formed under conditions of slight surface slopes and slow and calm river flows. Due to differences in the intensity and nature of erosion, the appearance of the river valleys of Western Siberia is very diverse. There are also well-developed deep (up to 50-80 m) valleys of large rivers - the Ob, Irtysh and Yenisei - with a steep right bank and a system of low terraces on the left bank. In some places their width is several tens of kilometers, and the Ob valley in the lower reaches reaches even 100-120 km. The valleys of most small rivers are often just deep ditches with poorly defined slopes; During spring floods, water completely fills them and even floods neighboring valley areas.

Currently, on the territory of the West Siberian Plain there is a slow shift of the boundaries of geographical zones to the south. Forests in many places encroach on the forest-steppe, forest-steppe elements penetrate into the steppe zone, and tundras slowly displace woody vegetation near the northern limit of sparse forests. True, in the south of the country man interferes with the natural course of this process: by cutting down forests, he not only stops their natural advance on the steppe, but also contributes to the shift of the southern border of forests to the north.