West Siberian Plain. Features of the nature of the West Siberian lowland or plain

West Siberian Plain(West Siberian lowland) - one of the largest accumulative lowland plains of the globe. It stretches 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 narrowing 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. It occupies the entire western part of Siberia from the Ural Mountains in the west to the Central Siberian Plateau in the east; the regions of Russia and Kazakhstan are located on it. The geographical position of the West Siberian Plain determines the transitional nature of its climate between the temperate continental climate of the Russian Plain and the sharply continental climate of Central Siberia. Therefore, the landscapes of the country are distinguished by a number of peculiar features: the natural zones here are somewhat shifted to the north compared to the Russian Plain, there is no zone of broad-leaved forests, and landscape differences within the zones are less noticeable than on the Russian Plain.

Geological structure and history of development

The West Siberian Plain is located within the epihercynian West Siberian Plate, the basement of which is composed of intensely dislocated and metamorphosed Paleozoic deposits, similar in nature to those of the Urals, and in the south of the Kazakh upland. The formation of the main folded structures of the basement of Western Siberia, which have a predominantly meridional direction, refers to the era of the Hercynian orogeny. They are everywhere covered with a cover of loose marine and continental Meso-Cenozoic rocks (clays, sandstones, marls, and the like) with a total thickness of more than 1000 m (in the basement 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, sea and ice-sea (thickness in places up to 4070 m).

The tectonic structure of the West Siberian plate is rather heterogeneous. However, even its large structural elements appear in the modern relief less distinctly than the tectonic structures of the Russian platform. This is explained by the fact that the relief of the surface of the Paleozoic rocks, lowered to a great depth, is leveled here by the cover of the Meso-Cenozoic deposits, the thickness of which exceeds 1000 m, and in individual depressions and syneclises of the Paleozoic basement - 3000-6000 m.

Significant changes in the conditions of accumulation of sedimentary deposits occurred in the Neogene. The suites of Neogene rocks, which come to the surface mainly in the southern half of the plain, consist exclusively of continental lacustrine-river deposits. They formed in the conditions of a poorly dissected plain, first covered with rich subtropical vegetation, and later with broad-leaved deciduous forests from representatives of the Turgai flora (beech, walnut, hornbeam, lapina, etc.). In some places there were areas of savannas, where giraffes, mastodons, hipparions, and camels lived at that time.

The events of the Quaternary period had a particularly great influence on the formation of the landscapes of Western Siberia. During this time, the territory of the country experienced repeated subsidence and was still an area of ​​predominantly accumulation of loose alluvial, lacustrine, and in the north - marine and glacial deposits. The thickness of the Quaternary cover reaches 200-250 m in the northern and central regions. However, in the south it noticeably decreases (up to 5-10 m in some places), and the impact of differentiated neotectonic movements is clearly expressed in the modern relief, as a result of which swell-like uplifts arose, often coinciding with positive structures of the Mesozoic sedimentary cover.

Lower Quaternary deposits are represented in the north of the plain by alluvial sands that fill buried valleys. The base of the alluvium is sometimes located in them 200-210 m below the modern level of the Kara Sea. Above them in the north, pre-glacial clays and loams with fossil remains of the tundra flora usually occur, which indicates a noticeable cooling of Western Siberia that had already begun at that time. However, in the southern regions of the country, dark coniferous forests with an admixture of birch and alder prevailed.

The Middle Quaternary time in the northern half of the plain was an epoch of marine transgressions and repeated glaciations. The most significant of them was Samarovskoye, the deposits of which compose the interfluves of the territory lying between 58-60 ° and 63-64 ° N. sh. According to currently prevailing views, the cover of the Samara glacier, even in the extreme northern regions of the lowland, was not continuous. The composition of boulders shows that its sources of food were glaciers descending from the Urals to the Ob valley, and in the east - glaciers of the Taimyr mountain ranges and the Central Siberian Plateau. However, even during the period of maximum development of glaciation in the West Siberian Plain, the Ural and Siberian ice sheets did not merge with each other, and the rivers of the southern regions, although they met a barrier formed by ice, found their way north in the gap between them.

Along with typical glacial rocks, the composition of the sediments of the Samarovo stratum also includes marine and glacial-marine clays and loams formed at the bottom of the sea advancing from the north. Therefore, the typical moraine relief forms are less distinct here than on the Russian Plain. On the lacustrine and fluvioglacial plains adjoining the southern edge of the glaciers, then forest-tundra landscapes prevailed, and in the extreme south of the country loess-like loams were formed, in which pollen of steppe plants (wormwood, kermek) is found. Marine transgression continued in the post-Samarovo time, the deposits of which are represented in the north of Western Siberia by the Messov sands and clays of the Sanchugov Formation. In the northeastern part of the plain, moraines and glacial-marine loams of the younger Taz glaciation are common. The interglacial epoch, which began after the retreat of the ice sheet, was marked in the north by the spread of the Kazantsevo marine transgression, whose deposits in the lower reaches of the Yenisei and Ob contained the remains of a more heat-loving marine fauna than currently living in the Kara Sea.

The last, Zyryansk, glaciation was preceded by a regression of the boreal sea, caused by uplifts in the northern regions of the West Siberian Plain, the Urals, and the Central Siberian Plateau; the amplitude of these uplifts was only a few tens of meters. During the maximum stage of development of the Zyryansk glaciation, glaciers descended into the regions of the Yenisei Plain and the eastern foot of the Urals to approximately 66 ° N. sh., where a number of stadial terminal moraines were left. In the south of Western Siberia, at that time, sandy-clay Quaternary deposits were being blown over, eolian landforms were formed, and loess-like loams were accumulating.

Some researchers of the northern regions of the country draw a more complex picture of the events of the Quaternary glaciation in Western Siberia. So, according to the geologist V.N. Saks and geomorphologist G.I. Lazukov, glaciation began here as early as the Lower Quaternary and consisted of four independent epochs: Yarskaya, Samarovo, Tazovskaya and Zyryanskaya. Geologists S.A. Yakovlev and V.A. Zubakov even counts six glaciations, referring the beginning of the most ancient of them to the Pliocene.

On the other hand, there are supporters of a one-time glaciation of Western Siberia. Geographer A.I. Popov, for example, considers the deposits of the glacial period of the northern half of the country as a single water-glacial complex consisting of marine and glacial-marine clays, loams and sands containing inclusions of boulder material. In his opinion, there were no extensive ice sheets on the territory of Western Siberia, since typical moraines are found only in the extreme western (at the foot of the Urals) and eastern (near the ledge of the Central Siberian Plateau) regions. The middle part of the northern half of the plain during the epoch of glaciation was covered by the waters of marine transgression; the boulders enclosed in its deposits are brought here by icebergs that have come off the edge of the glaciers that descended from the Central Siberian Plateau. Only one Quaternary glaciation of Western Siberia is recognized by the geologist V.I. Gromov.

At the end of the Zyryansk glaciation, the northern coastal regions of the West Siberian Plain again sank. The subsided areas were flooded by the waters of the Kara Sea and covered with marine sediments that make up the post-glacial marine terraces, the highest of which rises 50-60 m above the modern level of the Kara Sea. Then, after the regression of the sea, a new incision of rivers began in the southern half of the plain. Due to the small slopes of the channel in most of the river valleys of Western Siberia, lateral erosion prevailed, the deepening of the valleys proceeded slowly, therefore they usually have a considerable width, but a small depth. In the poorly drained interfluve spaces, the reworking of the ice age relief continued: in the north, it consisted in leveling the surface under the influence of solifluction processes; in the southern, non-glacial provinces, where more precipitation fell, the processes of deluvial washout played a particularly important role in the transformation of the relief.

Paleobotanical materials suggest that after the glaciation there was a period with a slightly drier and warmer climate than now. This is confirmed, in particular, by the findings of stumps and tree trunks in the deposits of the tundra regions of Yamal and the Gydan Peninsula at a distance of 300-400 km. to the north of the modern border of woody vegetation and the wide development of the tundra zone of relict large-hilly peatlands in the south.

Currently, in 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 advance on the forest-steppe, forest-steppe elements penetrate into the steppe zone, and the tundra is slowly replacing woody vegetation near the northern limit of sparse forests. True, in the south of the country, man intervenes in 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 displacement of the southern border of forests to the north.

Sources

• Gvozdetsky N.A., Mikhailov N.I. Physical geography of the USSR. Ed. 3rd. M., "Thought", 1978.

Literature

• West Siberian lowland. Essay on nature, M., 1963; Western Siberia, M., 1963.
• Davydova M.I., Rakovskaya E.M., Tushinsky G.K. Physical geography of the USSR. T. 1. M., Education, 1989.

The Russian Federation has one of the largest plains on the surface of the globe. In the north, it is bordered by the Kara Sea. In the south, it rubs off to the space of the Kazakh small sandpiper. The eastern part is the Central Siberian Plateau. The frontier in the west is ancient. The total area of ​​this flat space is almost 3 million kilometers.

In contact with

relief features

The territory where the West Siberian Plain is located was formed long ago and successfully survived all tectonic upheavals.

It is severely limited by officially recognized coordinates of extreme points:

• Cape Dezhnev, 169°42′ W, becomes the extreme eastern point on the mainland part of the space. d.;
• in the north, Cape Chelyuskin (Russia) becomes such a point, 77 ° 43′ N. sh.;
• coordinates 60° 00′ s. sh. 100° 00′ E d.

uplands

The height above sea level of the space under consideration is characterized by minimal differences.

It has the shape of a shallow dish. Elevation differences vary from 50 (minimum) to more than 100 meters in low areas, prevailing heights up to 200-250 meters located on the southern, western and eastern outskirts. On the northern outskirts, the elevation of the landscape is about 100-150 meters.

This is due to the location of the plain on the space of the epi-Hercynian plate, the basis of which is the foundation created by the imposition of Paleozoic deposits. This plate began to form in the Upper Jurassic, the so-called Upper Jurassic.

During the formation of the surface layer of the planet, the flat terrain, having sank, turned into a lowland and became a sedimentation basin. The site is located on the site located between the Urals and the Siberian platform.

Averages

This space belongs to the number of large low-lying areas on the planet, to the type of accumulative plains, has an average height of 200 meters. Low-lying areas are located in the central part of the area, in the northern areas, on the borders of the Kara Sea. Almost half space is located at an altitude of less than 100 meters above sea level. This ancient part of the earth's space also has its own "heights", smoothed over billions of years since its creation. For example, the North Sosvinskaya Upland (290 meters). The Upper Taz Upland rises to 285 meters.

low-lying places

The surface has a concave shape with minimal heights in the central part. The average minimum height is 100 meters. The reading is carried out according to tradition from sea level.

Fully justifies the name "plain". Elevation differences in a colossal space are minimal.

This feature also forms the continental climate. Frosts in some areas can drop to -50 degrees Celsius. Such indicators are noted, for example, in Barnaul.

In absolute terms, this territory also does not differ in large numbers. The absolute height here is only 290 meters. The parameters were fixed on the North Sosvenskaya Upland. In most of the plain, the figure is 100-150 meters.

This geographical feature occupies 1/7 of the Russian Federation. The plain stretches from the Kara Sea in the north to the Kazakh steppes in the south. In the west, it is limited by the Ural Mountains. The size is almost 3 million kilometers.

Characteristic

The general characteristic is based on the process of formation of the plain during the most ancient stages of the development of the planet and the long-term leveling of the surface during the passage of glacial masses. This explains the uniformity of the smoothed relief. Due to this, the space is strictly zoned. The north is distinguished by tundra, and south - steppe landscapes. The soil is minimally drained. Most of it is occupied by swampy forests and swamps directly. Such hydromorphic complexes occupy a large area, about 128 million hectares. The south of the plain is characterized by a large number of such spaces as various types of solods, solonetzes and large solonchaks.

Note! The climate of the plain, due to its large area, ranges from temperate continental in the Russian Plain to sharply continental. This indicator is different in Central Siberia.

For a long time people lived on the West Siberian Plain. Novgorodians came here already in the 11th century. Then they reached the lower reaches of the Ob. The period of opening space for the Russian state is associated with the legendary Yermak's campaigns from 1581 to 1584. It was at this time that many discoveries of lands were made in Siberia. The study of nature was carried out and described in the 18th century during the Great Northern and academic expeditions. Development in these places continued in the following decades. It was related:

• with the resettlement of the peasantry from Central Russia in the 19th century;
• planning the construction of the Siberian railway

Detailed soil and geographical maps of this land were compiled. Active development of the territories continued in the years after the change of state power in 1917 and beyond.

As a result, today it has become inhabited and mastered by man. Here are located such large regions of Russia as Pavlodar, Kustanai, Kokchetav regions, Altai Territory, the western regions of the Krasnoyarsk Territory, the eastern territories Sverdlovsk and Chelyabinsk regions.

About 150 years ago, the role of Siberia finally took shape as a kind of bridge between the European part of Russia and its eastern part. In our time, the role of this territory as an economic bridge, especially with the construction of the Baikal-Amur Mainline, has finally taken shape, using all types of transport for development.

Note! The active development of the territories is largely due to large volumes of deposits: natural gas, oil, brown coal, iron ores and many others.

The successful development of the territory was facilitated by a large number of large, which are mostly navigable, especially such giants as Ob, Irtysh, Yenisei. Nowadays, rivers are convenient transport routes, they are used to generate energy, which makes it possible to ensure a high level of quality of life for the population of the regions.

Age indicator

The basis of a smooth and even flat surface to the east of the Ural Mountains is a plate formed during the Paleozoic period. According to the parameters of the formation of the planet's surface, this plate is quite young. Over millions of years of formation, the surface of the plate was covered with Mesozoic and Cenozoic deposits.

According to their characteristics, they belong to the type of sea and sand- clay deposits. The layer thickness is up to 1000 meters. In the southern part, deposits in the form of loess reach a thickness of 200 meters and were formed due to the presence of areas of formation of lake deposits in these areas.

The West Siberian Plain (it will not be difficult to find it on the world map) is 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 the Ural Mountains to the mighty Yenisei. The whole area consists of two bowl-shaped flat depressions and many wetlands. Between these depressions stretch the Siberian Ridges, which rise to 180-200 meters.

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

Climatic conditions

The geographical position of the West Siberian Plain on the mainland causes interesting climatic conditions. Therefore, the weather in most of the plain has a temperate continental character. From the north, large arctic masses enter this territory, which bring with them severe cold in winter, and in summer the thermometer shows from + 5 ° С to + 20 ° С. In January, on the southern and northern sides, the temperature regime can range from -15 °С to -30 °С. The lowest indicator in winter was recorded in the north-east of Siberia - down to -45 °С.

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 the middle of summer, in July, the heat takes possession of 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

Describing the geographical position of the West Siberian Plain, it is necessary to talk about the water system. A huge number of rivers flow through this territory, as well as numerous lakes and swamps. The largest and most full-flowing river is the Ob with a tributary of the Irtysh. It is not only the largest in the region, but also one of the largest in the world. In terms of its area and length, the Ob dominates among the rivers of Russia. The water streams Pur, Nadym, Tobol and Taz, suitable for navigation, also flow here.

Plain in terms of the number of swamps is the world record holder. Such a vast territory cannot be found on the globe. Marshes occupy an area of ​​800 thousand square meters. km. There are several reasons for their formation: excessive moisture, a flat surface of the plain, a large amount of peat, and low air temperature.

Minerals

This region is rich in minerals. This is largely influenced by the geographical position of the West Siberian Plain. Oil and gas deposits are concentrated here in huge quantities. On its vast swampy areas there is a large supply 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 zone. The reason for such a poverty of plants is perennial glaciation, which does not allow plants to spread.

The fauna of the plain is also not very rich, despite the vast 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 with the rest of the regions, both neighboring ones, and the entire mainland of Eurasia.

The West Siberian Lowland covers an area of ​​about 3 million square kilometers. It covers 1/7 of the entire territory of Russia. The width of the plain varies. In the northern part it is about 800 km, and in the southern part it reaches 1900 km.

Areas

The West Siberian lowland is considered the most densely populated part of Siberia. On its territory there are several large regions, such as Omsk, Tyumen and Kurgan, as well as Novosibirsk and Tomsk. The greatest development of the lowland is noted in its southern part.

Climatic conditions

The climate in the lowland is dominated by continental, rather severe. Due to the large length of the West Siberian Plain from north to south, there are significant differences in the climate of the southern part from the northern one. The proximity of the Arctic Ocean plays an important role in the formation of weather conditions, as well as the fact that there are no obstacles on the plain to the movement of air masses from north to south and their mixing.

In the cold season, an area of ​​increased pressure appears over the southern part of the lowland, while in the north it decreases. Cyclones form at the boundary of air masses. Because of this, in regions located on the coast, the weather is very unstable in winter. can reach 40 meters per second. Winter throughout the territory of such a plain as the West Siberian Lowland is characterized by stable sub-zero temperatures, the minimum can reach -52 o C. Spring comes late and is cold and dry, warming occurs only in May.

In the warm season, the situation is reversed. Pressure rises over the Arctic Ocean, which causes northerly winds to blow throughout the summer. But they are pretty weak. July is considered the hottest time within the boundaries of the plain, called the West Siberian Lowland. During this period, in its northern part, the maximum temperature reaches 21 o C, and in the south - 40 o C. Such high marks in the south can be explained by the fact that the border with Kazakhstan and Central Asia passes here. This is where warm air masses come from.

The West Siberian lowland, whose height varies from 140 to 250 m, is characterized by winter with little precipitation. At this time of the year, only about 5-20 millimeters falls. What can not be said about the warm season, when 70% of annual precipitation pours onto the earth.

Permafrost is widespread in the northern part of the lowland. The earth freezes to a depth of 600 meters.

Rivers

So, compare the West Siberian Lowland and the Central Siberian Plateau. A strong enough difference will be that the plateau is indented by a huge number of rivers. There are practically no wetlands here. However, there are a lot of rivers on the plain. There are about 2 thousand of them. All of them together bring up to 1200 cubic kilometers of water into the Kara Sea every year. That's an amazing amount. After all, one cubic kilometer contains 1,000,000,000,000 (trillion) liters. Most of the rivers of Western Siberia are fed by melt water or precipitation in summer. Most of the water drains during the warm season. When a thaw occurs, the level in the rivers can rise by more than 15 meters, and in winter they are ice-bound. Therefore, during the cold period, the runoff is only 10%.

The rivers of this part of Siberia are characterized by slow currents. This is due to the flat terrain and slight slopes. For example, the Ob for 3,000 km drops by only 90 m. Because of this, the speed of its flow does not exceed half a meter per second.

lakes

There are even more lakes in these parts than rivers. And many times more. There are about a million of them. But almost all of them are small. A feature of local lakes is that many of them are filled with salt water. They also overflow very strongly in the spring. But over the summer they can significantly decrease in size, and by autumn they can completely disappear. During the last period, thanks to precipitation, the lakes are filled with water again, freeze in winter, and the cycle repeats. This is not the case with all water bodies, but with the so-called “mist” lakes that occupy the territory of this lowland - the West Siberian Plain. It is also characterized by another type of lakes. They occupy the natural unevenness of the relief, various pits and depressions.

swamps

Another feature of Western Siberia is that it beats all records in terms of the number of swamps. It is within the boundaries of this lowland that spilled which are considered one of the largest on the entire globe. Increased waterlogging is due to the high content of peat in the ground. The substance is able to retain a lot of water, because of this, “dead” areas appear. The area itself also contributes to the formation of swamps. The plain without drops does not allow water to drain, and it remains in a practically motionless state, eroding and softening the soil.

natural areas

Due to the fact that Western Siberia is strongly stretched from north to south, transitions are observed in it. They change from tundra in the north to deserts and semi-deserts in the south. Part of the lowland is occupied by the tundra zone, which is explained by the general northern position of the entire territory of the plain. To the south, the tundra gradually turns into the forest-tundra, and then into the forest-bog zone. The latter occupies 60% of the entire territory of Western Siberia.

There is a rather sharp transition to the steppe regions. Birch is the most common here, as well as aspen. In addition to them, the Plowed Steppe Zone also occupies the extreme southern position in the plain. The West Siberian lowland, whose geographical position is directly related to the distribution by zones, also creates favorable conditions for a pine forest located on low sandy spits.

The region is rich in representatives of the animal world. For example, about 99 species of mammals live here. Among them are fur-bearing animals such as arctic foxes, weasels and sables. There are large predators - bears and lynxes. Also, many birds live in these parts. In the reserves there are peregrine falcons, hawks and golden eagles. There are also birds listed in the Red Book. For example, a black stork or a white-tailed eagle.

Mineral resources

Compare the geographical location of the West Siberian Lowland with any other, and it will become clear that it is in the described plain that about 70% of oil production is concentrated. The plain is also rich in coal deposits. The total area of ​​land rich in these resources is estimated at 2 million square meters. km. The timber industry is also well developed. The greatest advantage is given to coal mining in the Kuzbass.

Central Siberian Plateau

Compared to the West Siberian Lowland, the Central Siberian Plateau is not waterlogged due to the fact that it is located on a hill. However, the river system is denser, which is also fed by rain and melting snow. Permafrost is ubiquitous. The climate on the plateau is sharply continental, which is why, as in the West Siberian Lowland, there are large temperature fluctuations in winter. The average in the north reaches -44 o C, and in the south -22 o C. This is also typical for the summer period. There is less variety of animals, but bears, reindeer and hares are also found. The plateau, as well as rich in oil and gas deposits. To this are added various ores and

WESTERN SIBERIAN PLAIN, The West Siberian Lowland, one of the largest plains in the world (the third largest after the Amazonian and East European plains), is located in the north of Asia, in Russia and Kazakhstan. It occupies the whole of Western Siberia, stretching from the coast of the Arctic Ocean in the north to the Turgai plateau and the Kazakh uplands in the south, from the Urals in the west to the Central Siberian plateau in the east. The length from north to south is up to 2500 km, from west to east from 900 km in (north) to 2000 (in south). The area is about 3 million km 2, including 2.6 million km 2 in Russia. The prevailing heights do not exceed 150 m. The lowest parts of the plain (50–100 m) are located mainly in its central (Kondinskaya and Sredneobskaya lowlands) and northern (Nizhneobskaya, Nadymskaya and Purskaya lowlands) parts. The highest point of the West Siberian Plain - up to 317 m - is located on the Priobsky Plateau.

At the base of the West Siberian Plain lies West Siberian platform. To the east it borders on Siberian platform, in the south - with Paleozoic structures of Central Kazakhstan, the Altai-Sayan region, in the west - with the folded system of the Urals.

Relief

The surface is a low accumulative plain with a rather uniform relief (more uniform than that of the East European Plain), the main elements of which are wide flat interfluves and river valleys; various forms of manifestation of permafrost (common up to 59 ° N), increased waterlogging, and developed (mainly in the south in loose rocks and soils) ancient and modern salt accumulation are characteristic. In the north, in the area of ​​​​distribution of marine accumulative and moraine plains (Nadymskaya and Purskaya lowlands), the general flatness of the territory is disturbed by moraine gently sloping and hilly-sloping (North-Sosvinskaya, Lyulimvor, Verkhne-, Srednetazovskaya, etc.) uplands 200–300 m high, the southern boundary of which runs around 61–62 ° N. sh.; they are horseshoe-shaped covered from the south by flat-topped uplands, among which are the Poluyskaya Upland, Belogorsky Mainland, Tobolsky Mainland, Siberian Uvaly (245 m), etc. In the north, permafrost exogenous processes (thermal erosion, heaving of soils, solifluction) are widespread, deflation is common on sandy surfaces, in swamps - peat accumulation. Permafrost is ubiquitous on the Yamal, Tazovsky, and Gydansky peninsulas; the thickness of the frozen layer is very significant (up to 300–600 m).

To the south, the area of ​​moraine relief is adjoined by flat lacustrine and lacustrine-alluvial lowlands, the lowest (40–80 m high) and swampy of which are the Konda lowland and the Sredneobskaya lowland with the Surgut lowland (105 m high). This territory, not covered by the Quaternary glaciation (to the south of the line Ivdel - Ishim - Novosibirsk - Tomsk - Krasnoyarsk), is a poorly dissected denudation plain, rising up to 250 m to the west, to the foothills of the Urals. In the interfluve of the Tobol and the Irtysh, there is an inclined, in places with ridges, lacustrine-alluvial Ishim Plain(120–220 m) with a thin cover of loess-like loams and loess occurring on salt-bearing clays. It is adjacent to alluvial Baraba lowland, Vasyugan Plain and Kulunda Plain, where the processes of deflation and modern salt accumulation are developed. In the foothills of Altai - the Ob plateau and the Chulym plain.

On the geological structure and minerals, see Art. West Siberian platform ,

Climate

The West Siberian Plain is dominated by a harsh continental climate. The significant length of the territory from north to south determines the well-defined latitudinal zonality of the climate and noticeable differences in the climatic conditions of the northern and southern parts of the plain. The nature of the climate is significantly influenced by the Arctic Ocean, as well as the flat relief, which contributes to the unhindered exchange of air masses between north and south. Winter in the polar latitudes is severe and lasts up to 8 months (the polar night lasts almost 3 months); the average January temperature is from -23 to -30 °C. In the central part of the plain, winter lasts almost 7 months; the average January temperature is from -20 to -22 °C. In the southern part of the plain, where the influence of the Asian anticyclone is increasing, at the same average monthly temperatures, winter is shorter - 5–6 months. Minimum air temperature -56 °C. The duration of snow cover in the northern regions reaches 240–270 days, and in the southern regions - 160–170 days. The thickness of the snow cover in the tundra and steppe zones is 20–40 cm; in the forest zone, from 50–60 cm in the west to 70–100 cm in the east. In summer, the western transfer of Atlantic air masses predominates with intrusions of cold Arctic air in the north, and dry warm air masses from Kazakhstan and Central Asia in the south. In the north of the plain, summer, which occurs under polar day conditions, is short, cool, and humid; in the central part - moderately warm and humid, in the south - arid and dry with dry winds and dust storms. The average July temperature rises 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 (from May to October - up to 80% of precipitation). Most precipitation - up to 600 mm per year - falls in the forest zone; the wettest are the Kondinskaya and Sredneobskaya lowlands. To the north and south, in the tundra and steppe zone, the annual precipitation gradually decreases to 250 mm.

surface water

On the territory of the West Siberian Plain, more than 2,000 rivers flow, belonging to the basin of the Arctic Ocean. 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 - the Ob, Yenisei, Irtysh, Taz and their tributaries - flow in well developed deep (up to 50–80 m) valleys with a steep right bank and a system of low terraces on the left bank. The feeding of the rivers is mixed (snow and rain), the spring flood is extended, the low water is long summer-autumn and winter. All rivers are characterized by slight slopes and low flow rates. The ice cover on the rivers lasts up to 8 months in the north, up to 5 months in the south. Large rivers are navigable, are important rafting and transportation routes, and, in addition, have large reserves of hydropower resources.

There are about 1 million lakes on the West Siberian Plain, the total area of ​​which is more than 100 thousand km2. The largest lakes are Chany, Ubinskoye, Kulundinskoye, and others. Lakes of thermokarst and moraine-glacial origin are widespread in the north. There are many small lakes in the suffusion depressions (less than 1 km 2): on the interfluve of the Tobol and Irtysh - more than 1500, on the Baraba lowland - 2500, among them there are many fresh, salty and bitter-salty ones; there are self-sustaining lakes. The West Siberian Plain is distinguished by a record number of swamps per unit area (the area of ​​the wetland is about 800 thousand km 2).

Landscape types

The uniformity of the relief of the vast West Siberian Plain determines the clearly pronounced latitudinal zonality of landscapes, although, compared with the East European Plain, the natural zones here are shifted to the north; landscape differences within the zones are less noticeable than on the East European Plain, and the zone of broad-leaved forests is absent. Due to the poor drainage of the territory, hydromorphic complexes play a prominent role: swamps and swampy forests occupy about 128 million hectares here, and in the steppe and forest-steppe zones there are many solonetzes, solods and solonchaks.

On the Yamal, Tazovsky and Gydansky peninsulas, in conditions of continuous permafrost, landscapes of arctic and subarctic tundra with moss, lichen and shrub (dwarf birch, willow, alder) vegetation have formed on gleyzems, peat-gleyzems, peat-podburs and soddy soils. Polygonal grass-hypnum swamps are widespread. The share of primary landscapes is extremely insignificant. To the south, tundra landscapes and swamps (mostly flat-hummocky) are combined with larch and spruce-larch light forests on podzolic-gley and peat-podzolic-gley soils, forming a narrow forest-tundra zone, transitional to the forest (forest-bog) zone of the temperate zone, represented by subzones of the northern, middle and southern taiga. Swampiness is common to all subzones: over 50% of the area of ​​the northern taiga, about 70% of the middle taiga, and about 50% of the southern taiga. The northern taiga is characterized by flat and large hillocky raised bogs, the middle taiga is characterized by ridge-hollow and ridge-lake bogs, the southern taiga is characterized by ridge-hollow, pine-shrub-sphagnum, transitional sedge-sphagnum and low-lying tree-sedge bogs. The largest swamp Vasyugan Plain. The forest complexes of different subzones, formed on slopes with different degrees of drainage, are peculiar.

Northern taiga forests on permafrost are represented by sparse low-growing, heavily waterlogged, pine, pine-spruce and spruce-fir forests on gley-podzolic and podzolic-gley soils. The indigenous landscapes of the northern taiga occupy 11% of the plain area. Indigenous landscapes in the middle taiga occupy 6% of the area of ​​the West Siberian Plain, in the southern - 4%. 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 illuvial-ferruginous and illuvial-humus podzols. On loams in the middle taiga, along with extensive swamps, spruce-cedar forests with larch and birch forests are developed on podzolic, podzolic-gley, peat-podzolic-gley and gley peat-podzols.

In the subzone of the southern taiga on loams - spruce-fir and fir-cedar (including urman - dense dark coniferous forests with a predominance of fir) small-grass forests and birch forests with aspen on sod-podzolic and sod-podzolic-gley (including with a second humus horizon) and peat-podzolic-gley soils.

The subtaiga zone is represented by park pine, birch and birch-aspen forests on gray, gray gley and soddy-podzolic soils (including those with a second humus horizon) in combination with steppe meadows on cryptogley chernozems, solonetsous in places. Indigenous forest and meadow landscapes are practically not preserved. Boggy forests turn into lowland sedge-hypnum (with ryams) and sedge-reed bogs (about 40% of the zone). Forest-steppe landscapes of sloping plains with loess-like and loess covers on salt-bearing tertiary clays are characterized by birch and aspen-birch groves on gray soils and solods in combination with forb-grass steppe meadows on leached and cryptogleyed chernozems, to the south - with meadow steppes on ordinary chernozems, in places solonetzic and saline. On the sands are pine forests. Up to 20% of the zone is occupied by eutrophic reed-sedge bogs. In the steppe zone, the primary landscapes have not been preserved; in the past, these were forb-feather grass steppe meadows on ordinary and southern chernozems, sometimes saline, and in drier southern regions - fescue-feather grass steppes on chestnut and cryptogley soils, gley solonetzes and solonchaks.

Environmental issues and protected natural areas

In areas of oil production due to pipeline breaks, water and soil are polluted with oil and oil products. In forestry areas - overcutting, waterlogging, the spread of silkworms, 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 habitats of fauna.

Numerous reserves, national and natural parks have been created to study and protect typical and rare natural landscapes. Among the largest reserves: in the tundra - the Gydansky reserve, in the northern taiga - the Verkhnetazovsky reserve, in the middle taiga - the Yugansky reserve and Malaya Sosva, etc. The national park Pripyshminsky Bory was created in the subtaiga. Natural parks are also organized: in the tundra - Deer streams, in the north. taiga - Numto, Siberian Ridges, in the middle taiga - Kondinsky lakes, in the forest-steppe - Bird's harbor.

The first acquaintance of Russians with Western Siberia took place, probably, as early as the 11th century, when the Novgorodians visited the lower reaches of the Ob River. With the campaign of Yermak (1582–85), a period of discoveries began in Siberia and the development of its territory.