On what platform is the West Siberian Plain located. Physical Geography - Western Siberia (West Siberian Plain)

The West Siberian Plain is one of the largest accumulative low-lying plains in the world. 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.

The relief of the West Siberian Plain is one of the most uniform 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 the Altai Mountains, for 2400 km. Only in the extreme south do heights exceed 200 m; the vast majority of the plain has a height of less than 100 m above sea level; alluvial-lacustrine and accumulative relief prevails (in the south also denudation). Such relief features characteristic of Western Siberia as vast floodplains and huge swamps are especially common in the northern part of the plain; the relief to the 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. Valleys of large rivers are terraced. There are eolian dunes on the Yamal and Gydan peninsulas. Relatively elevated and dry territories, where the main part of the population of Western Siberia is concentrated, are located south of 55 °C.

Differentiated lowerings West Siberian plate in the Mesozoic and Cenozoic, they determined the predominance within its boundaries of the processes of accumulation of loose deposits, the powerful cover of which levels the unevenness of the surface of the Hercynian basement. Therefore, the modern West Siberian Plain is characterized by a generally flat surface. However, it cannot be considered as a monotonous lowland, as it was considered until recently. 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 (Nizhnoeobskaya, Nadymskaya and Purskaya lowlands) parts of the country. Low (up to 200-250 m) elevations stretch along the western, southern and eastern outskirts: the North Sosvinskaya, Turinskaya, Ishimskaya, Priobskoye and Chulym-Yenisei plateaus, the Ketsko-Tymskaya, Verkhnetazovskaya, Nizhneeniseiskaya. A distinctly pronounced strip of uplands is formed in the inner part of the plain by the Siberian Uvals (average height - 140-150 m), extending 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 uplands, and the Baraba and Kondinsky lowlands are confined to the syneclises of the slab basement. However, discordant (inversion) morphostructures are also not uncommon in Western Siberia. 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 basement trough zone.

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) near-glacial, mainly lacustrine-alluvial, plains; 4) southern non-glacial plains (Voskresensky, 1962).
Differences in the relief of these areas are explained by the history of their formation in the Quaternary, the nature and intensity of the latest 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 a harsh climate and the widespread distribution of permafrost. Thermokarst basins, bulgunnyakhs, spotted and polygonal tundras are quite common, and solifluction processes are developed. The southern steppe provinces are characterized by numerous closed basins of suffusion origin, occupied by salt marshes and lakes; the network of river valleys here is not dense, and erosional landforms in the interfluves are rare.

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 certain northern provinces of the plain, which were subjected to Quaternary glaciations, which left here a heap 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 the northeast to the southwest.

Western Siberia. Photo: Bernt Rostad

Another important element relief of the country - river valleys. All of them were formed in conditions of small slopes of the surface, slow and calm flow of rivers. 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 places, their width is several tens of kilometers, and the Ob valley in the lower reaches even 100-120 km. The valleys of most small rivers are often only deep ditches with poorly defined slopes; during spring floods, water completely fills them and floods even neighboring valley areas.

Currently, there is a slow shift of borders on the territory of the West Siberian Plain. geographical areas 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: 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.

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 diversity of the tectonic structure, this territory was divided into several individual regions. One of them is Western Siberia.

The basis of Western Siberia is the West Siberian Plain. It is bounded in the west by the Ural Mountains, and in the east by the Yenisei River. In the north, the plain is washed by the waters of the seas of the Arctic Ocean. The southern borders approach the Kazakh uplands and the Turgai plateau. The total area of the plain 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, the southeastern part of the plain 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, the geological history determined 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 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 the layers rocks 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.

general characteristics

The West Siberian Plain is one of the largest accumulative low-lying plains in the world. 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 tapering to the north: the distance from its southern border to the northern reaches almost 2500 km, width - from 800 to 1900 km, and the area is only slightly less than 3 million sq. km 2 .

There are no other such vast plains in the Soviet Union, with such a poorly broken relief and such small fluctuations in relative heights. The comparative uniformity of the relief determines the distinct zonality of the landscapes of Western Siberia - from tundra in the north to steppe in the south. Due to the poor drainage of the territory within its boundaries, hydromorphic complexes play a very prominent role: swamps and swampy forests occupy here in total about 128 million ha, and in the steppe and forest-steppe zones there are many solonetzes, solods and solonchaks.

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, the zone of broad-leaved forests is absent, and landscape differences within the zones are less noticeable than on the Russian Plain.

The West Siberian Plain is the most inhabited and developed (especially in the south) part of Siberia. Within its boundaries are the Tyumen, Kurgan, Omsk, Novosibirsk, Tomsk and North Kazakhstan regions, a significant part of the Altai Territory, Kustanai, Kokchetav and Pavlodar regions, as well as some eastern regions of the Sverdlovsk and Chelyabinsk regions and western areas Krasnoyarsk region.

The acquaintance of Russians with Western Siberia took place for the first time, probably, as early as the 11th century, when the Novgorodians visited the lower reaches of the Ob. Ermak's campaign (1581-1584) opens a brilliant period of the Great Russian geographical discoveries in Siberia and the development of its territory.

However, the scientific study of the nature of the country began only in the 18th century, when detachments of the Great Northern expedition and then academic expeditions were sent here. In the 19th century Russian scientists and engineers are studying the conditions of navigation on the Ob, Yenisei and the Kara Sea, the geological and geographical features of the route of the Siberian railway that was being designed at that time, salt deposits in the steppe zone. A significant contribution to the knowledge of the West Siberian taiga and steppes was made by studies of soil-botanical expeditions of the Resettlement Administration, undertaken in 1908-1914. in order to study the conditions for the agricultural development of plots allocated for the resettlement of peasants from European Russia.

The study of the nature and natural resources of Western Siberia acquired a completely different scope after the Great October Revolution. In the research that was necessary for the development of the productive forces, no longer individual specialists or small detachments took part, but hundreds of large complex expeditions and many scientific institutes created in various cities of Western Siberia. Detailed and versatile studies were carried out here by the USSR Academy of Sciences (Kulunda, Baraba, Gydan and other expeditions) and its Siberian branch, the West Siberian Geological Administration, geological institutes, expeditions of the Ministry of Agriculture, Hydroproject and other organizations.

As a result of these studies, ideas about the country's relief have changed significantly, detailed soil maps of many regions of Western Siberia have been compiled, and measures have been developed for the rational use of saline soils and the famous West Siberian chernozems. big practical value had forest typological studies of Siberian geobotanists, the study of peat bogs and tundra pastures. But especially significant results were brought by the work of geologists. Deep drilling and special geophysical studies have shown that in the bowels of many regions of Western Siberia are the richest deposits of natural gas, large reserves iron ores, brown coal and many other minerals, which already serve as a solid base for the development of industry in Western Siberia.

Geological structure and history of the development of the territory

of the Taz Peninsula and the Middle Ob in the section Nature of the World Song and Cry of Mother Earth, "dedicated to the beauty of nature and environmental problems of Western Siberia and illustrated by the author's photographs.

Many features of the nature of Western Siberia are due to the nature of its geological structure and history of development. The entire territory of the country is located within the West Siberian epihercynian plate, the foundation of which is composed of 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.

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 topography of the surface of the Paleozoic rocks, subsided to a great depth, is leveled here by the cover of the Meso-Cenozoic deposits, the thickness of which exceeds 1000 m, and in separate depressions and syneclises of the Paleozoic basement - 3000-6000 m.

The Mesozoic formations of Western Siberia are represented by marine and continental sandy-argillaceous deposits. Their total capacity in some areas reaches 2500-4000 m. The alternation of marine and continental facies indicates the tectonic mobility of the territory and repeated changes in the conditions and regime of sedimentation on the West Siberian Plate that sank at the beginning of the Mesozoic.

Paleogene deposits are predominantly marine and consist of gray clays, mudstones, glauconite sandstones, opokas, and diatomites. They accumulated at the bottom of the Paleogene Sea, which, through the depression of the Turgai Strait, connected the Arctic Basin with the seas that were then located on the territory Central Asia. This sea left Western Siberia in the middle of the Oligocene, and therefore the Upper Paleogene deposits are already represented here by sandy-clayey continental facies.

Significant changes in the conditions of accumulation of sedimentary deposits occurred in the Neogene. Suites of rocks of the Neogene age, coming to the surface mainly in southern half plains, 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.

Especially big influence the formation of the landscapes of Western Siberia was influenced by the events of the Quaternary period. 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 in the northern and central regions reaches 200-250 m. However, in the south it noticeably decreases (in some places up to 5-10 m), and in the modern relief, the effects of differentiated neotectonic movements are clearly expressed, as a result of which swell-like uplifts arose, often coinciding with the positive structures of the Mesozoic cover of sedimentary deposits.

Lower Quaternary deposits are represented in the north of the plain by alluvial sands filling buried valleys. The sole of alluvium is located in them sometimes at 200-210 m below the current 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 southern regions The country was dominated by dark coniferous forests with an admixture of birch and alder.

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 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, sandy-argillaceous Quaternary sediments were being blown over at that time, eolian landforms were forming, and loess-like loams were accumulating.

Some researchers northern regions countries draw a more complex picture of the events of the Quaternary glaciation in Western Siberia. Thus, 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, Taz and Zyryanskaya. Geologists S. A. Yakovlev and V. A. Zubakov even count 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 glaciation era 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 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 atmospheric precipitation fell, the processes of deluvial washout played a particularly prominent 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 finds of stumps and tree trunks in the deposits of the tundra regions of Yamal and the Gydan Peninsula at 300-400 km north modern border woody vegetation and the wide development of relict large-hilly peatlands in the south of the tundra zone.

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: 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.

Relief

See photos of the nature of the West Siberian Plain: the Taz Peninsula and the Middle Ob in the Nature of the World section, and also read the book by V.P. Nazarov "Song and Cry of Mother Earth", dedicated to the beauty of nature and environmental problems of Western Siberia and illustrated with photographs of the author.

Scheme of the main orographic elements of the West Siberian Plain

Differentiated subsidence of the West Siberian Plate in the Mesozoic and Cenozoic determined the predominance of accumulation processes of loose deposits within it, the thick cover of which levels the unevenness of the surface of the Hercynian basement. Therefore, the modern West Siberian Plain is characterized by a generally flat surface. However, it cannot be considered as a monotonous lowland, as it was considered until recently. In general, the territory of Western Siberia has a concave shape. Its lowest parts (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: Severo-Sosvinskaya, Turin, Ishimskaya, Priobskoe and Chulym-Yenisei plateau, Ketsko-Tymskaya, Verkhnetazovskaya, Lower Yenisei. A distinct strip of hills form in the inner part of the plain Siberian Ridges(average height - 140-150 m), stretching from the west from the Ob to the east to the Yenisei, and parallel to them Vasyuganskaya plain.

Some orographic elements of the West Siberian Plain correspond to geological structures: gently sloping anticlinal uplifts correspond, for example, to the Verkhnetazovsky and lulimvor, a Barabinskaya and Kondinskaya the lowlands are confined to the syneclises of the slab basement. However, discordant (inversion) morphostructures are also not uncommon in Western Siberia. 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 basement trough zone.

The differences in the relief of these areas are explained by the history of their formation in the Quaternary, the nature and intensity of the latest 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 a harsh climate and the widespread distribution of permafrost. Thermokarst basins, bulgunnyakhs, spotted and polygonal tundras are quite common, and solifluction processes are developed. The southern steppe provinces are characterized by numerous closed basins of suffusion origin, occupied by salt marshes and lakes; the network of river valleys here is not dense, 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 a large part of the country's area, they determine the general appearance of the relief of the plain. In many places, the slopes of their surface are insignificant, the runoff of precipitation, especially in the forest-bog zone, is very difficult, and the interfluves are heavily swamped. Large areas are occupied by swamps to the north of the line of the Siberian railway, on the interfluve of the Ob and Irtysh, in the Vasyugan region and the Baraba 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 certain northern provinces of the plain, which were subjected to Quaternary glaciations, which left here a heap 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 the northeast to the southwest.

Another important element of the country's relief is the river valleys. All of them were formed in conditions of small slopes of the surface, slow and calm flow of rivers. 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 places, their width is several tens of kilometers, and the Ob valley in the lower reaches even 100-120 km. The valleys of most small rivers are often only deep ditches with poorly defined slopes; during spring floods, water completely fills them and floods even neighboring valley areas.

Climate

Western Siberia is a country with a fairly severe continental climate. Its large length from north to south determines a clearly pronounced climate zoning and significant differences in climatic conditions in the northern and southern parts of Western Siberia, associated with a change in the amount of solar radiation and the nature of the circulation of air masses, especially western transport flows. The southern provinces of the country, located inland, at a great distance from the oceans, are also characterized by a more continental climate.

During the cold period, two baric systems interact within the country: an area of relatively high atmospheric pressure, located above the southern part of the plain, an area of low pressure, which in the first half of winter extends in the form of a hollow of the Icelandic baric minimum over the Kara Sea and northern peninsulas. In winter, masses of continental air of temperate latitudes predominate, which come from Eastern Siberia or are formed on the spot as a result of air cooling over the territory of the plain.

Cyclones often pass in the border zone of areas of high and low pressure. Especially often they are repeated in the first half of winter. Therefore, the weather in the maritime provinces is very unstable; on the coast of Yamal and the Gydan Peninsula vouch strong winds, the speed of which reaches 35-40 m/s. The temperature here is even somewhat higher than in the neighboring forest-tundra provinces located between 66 and 69°N. sh. Further south, however, winter temperatures gradually rise again. In general, winter is characterized by stable low temperatures, there are few thaws here. The minimum temperatures throughout Western Siberia are almost the same. Even near the southern border of the country, in Barnaul, there are frosts down to -50 -52 °, i.e., almost the same as in the far north, although the distance between these points is more than 2000 km. Spring is short, dry and comparatively cold; April, even in the forest-marsh zone, is not yet quite a spring month.

In the warm season, low pressure sets in over the country, and an area of higher pressure forms over the Arctic Ocean. In connection with this summer, weak northerly or northeasterly winds predominate, and the role of western air transport noticeably increases. In May, there is a rapid increase in temperatures, but often, with the intrusions of arctic air masses, there are returns of cold weather and frosts. The warmest month is July, the average temperature of which is from 3.6° on Bely Island to 21-22° in the Pavlodar region. The absolute maximum temperature is from 21° in the north (Bely Island) to 40° in the extreme southern regions (Rubtsovsk). High summer temperatures in the southern half of Western Siberia are explained by the inflow of heated continental air here from the south - from Kazakhstan and Central Asia. Autumn comes late. Even in September, the weather is warm during the day, but November, even in the south, is already a real winter month with frosts up to -20 -35 °.

Most of the precipitation falls in the summer and is brought by air masses coming from the west, from the Atlantic. From May to October, Western Siberia receives up to 70-80% of the annual precipitation. There are especially many of them in July and August, which is explained by intensive activity on the Arctic and polar fronts. The amount of winter precipitation is relatively low and ranges from 5 to 20-30 mm/month. In the south, in some winter months, snow sometimes does not fall at all. Significant fluctuations in the amount of precipitation in different years are characteristic. Even in the taiga, where these changes are less than in other zones, precipitation, for example, in Tomsk, falls from 339 mm in a dry year up to 769 mm into wet. Especially large differences are observed in the forest-steppe zone, where, with an average long-term precipitation of about 300-350 mm/year in wet years falls up to 550-600 mm/year, and in dry - only 170-180 mm/year.

There are also significant zonal differences in evaporation values, which depend on the amount of precipitation, air temperature, and the evaporative properties of the underlying surface. Moisture evaporates most of all in the rainy-rich southern half of the forest-bog zone (350-400 mm/year). In the north, in the coastal tundra, where the air humidity is relatively high in summer, the amount of evaporation does not exceed 150-200 mm/year. It is approximately the same in the south of the steppe zone (200-250 mm), which is already explained by the low amount of precipitation falling in the steppes. However, evaporation here reaches 650-700 mm, therefore, in some months (especially in May), the amount of evaporating moisture can exceed the amount of precipitation by 2-3 times. In this case, the lack of atmospheric precipitation is compensated by the reserves of moisture in the soil accumulated due to autumn rains and melting snow cover.

The extreme southern regions of Western Siberia are characterized by droughts, which occur mainly in May and June. They are observed on average every three to four years during periods with anticyclonic circulation and increased frequency of arctic air intrusions. The dry air coming from the Arctic, when passing over Western Siberia, is warmed up and enriched with moisture, but its heating is more intense, so the air is increasingly moving away from the state of saturation. In this regard, evaporation increases, which leads to drought. In some cases, the cause of droughts is also the inflow of dry and warm air masses from the south - from Kazakhstan and Central Asia.

In winter, the territory of Western Siberia is covered with snow for a long time, the duration of which in the northern regions reaches 240-270 days, and in the south - 160-170 days. Due to the fact that the period of precipitation in solid form lasts more than six months, and thaws begin no earlier than March, the thickness of the snow cover in the tundra and steppe zones in February is 20-40 cm, in the swampy zone - from 50-60 cm in the west up to 70-100 cm in the eastern Yenisei regions. In treeless - tundra and steppe - provinces, where strong winds and snowstorms occur in winter, snow is distributed very unevenly, as the winds blow it from elevated relief elements into depressions, where powerful snowdrifts form.

The harsh climate of the northern regions of Western Siberia, where the heat entering the soil is not enough to maintain a positive temperature of the rocks, contributes to the freezing of soils and the widespread permafrost. On the Yamal, Tazovsky and Gydansky peninsulas, permafrost is found everywhere. In these areas of its continuous (confluent) distribution, the thickness of the frozen layer is very significant (up to 300-600 m), and its temperatures are low (on the watershed spaces - 4, -9 °, in the valleys -2, -8 °). Further south, within the limits of the northern taiga up to a latitude of about 64°, permafrost occurs already in the form of isolated islands interspersed with taliks. Its power decreases, temperatures rise to? 0.5 -1 °, and the depth of summer thawing also increases, especially in areas composed of mineral rocks.

Water

Western Siberia is rich in underground and surface waters; in the north, its coast is washed by the waters of the Kara Sea.

The entire territory of the country is located within the large West Siberian artesian basin, in which hydrogeologists distinguish several basins of the second order: Tobolsk, Irtysh, Kulunda-Barnaul, Chulym, Ob, etc. Due to the large thickness of the cover of loose deposits, consisting of alternating permeable ( sands, sandstones) and water-resistant rocks, artesian basins are characterized by a significant number of aquifers associated with suites of various ages - Jurassic, Cretaceous, Paleogene and Quaternary. The groundwater quality of these horizons is very different. In most cases, artesian waters of deep horizons are more mineralized than those lying closer to the surface.

In some aquifers of the Ob and Irtysh artesian basins at a depth of 1000-3000 m there are hot salty waters, most often of chloride calcium-sodium composition. Their temperature is from 40 to 120°C, the daily flow rate of wells reaches 1-1.5 thousand tons per day. m 3, and total stocks - 65,000 km 3; such pressure water can be used for heating cities, greenhouses and greenhouses.

Groundwater in arid steppe and forest-steppe regions of Western Siberia has great importance for water supply. In many areas of the Kulunda steppe, deep tubular wells were built to extract them. Quaternary groundwater is also used; however, in the southern regions, due to climatic conditions, poor drainage of the surface and slow circulation, they are often highly saline.

The surface of the West Siberian Plain is drained by many thousands of rivers, the total length of which exceeds 250 thousand km. km. These rivers carry out into the Kara Sea annually about 1200 km 3 water - 5 times more than the Volga. The density of the river network is not very large and varies in different places depending on the relief and climatic features: in the Tavda basin it reaches 350 km, and in the Baraba forest-steppe - only 29 km per 1000 km 2. Some southern regions of the country with a total area of more than 445,000 sq. km 2 belong to the territories of closed flow and are distinguished by an abundance of endorheic lakes.

The main sources of food for most rivers are melted snow water and summer-autumn rains. In accordance with the nature of food sources, the runoff is seasonally uneven: approximately 70-80% of its annual amount occurs in spring and summer. Especially a lot of water flows down during the spring flood, when the level of large rivers rises by 7-12 m(in the lower reaches of the Yenisei even up to 15-18 m). For a long time (in the south - five, and in the north - eight months) the West Siberian rivers are ice-bound. Therefore, the winter months account for no more than 10% of the annual runoff.

The rivers of Western Siberia, including the largest ones - the Ob, Irtysh and Yenisei, are characterized by slight slopes and low flow rates. So, for example, the fall of the Ob channel in the section from Novosibirsk to the mouth over 3000 km equals only 90 m, and its flow rate does not exceed 0.5 m/s.

The most important water artery of Western Siberia is the river Ob with its large left tributary the Irtysh. The Ob is one of the greatest rivers in the world. The area of its basin is almost 3 million hectares. km 2 and the length is 3676 km. The Ob basin is located within several geographical zones; in each of them, the nature and density of the river network are different. So, in the south, in the forest-steppe zone, the Ob receives relatively few tributaries, but in the taiga zone their number noticeably increases.

Below the confluence of the Irtysh, the Ob turns into a powerful stream up to 3-4 km. Near the mouth, the width of the river in places reaches 10 km, and depth - up to 40 m. This is one of the most abundant rivers in Siberia; it brings an average of 414 km 3 water.

The Ob is a typical flat river. The slopes of its channel are small: the fall in the upper part is usually 8-10 cm, and below the mouth of the Irtysh does not exceed 2-3 cm for 1 km currents. During spring and summer, the runoff of the Ob near Novosibirsk is 78% per annum; Near the mouth (near Salekhard), the seasonal distribution of runoff is as follows: winter - 8.4%, spring - 14.6, summer - 56 and autumn - 21%.

Six rivers of the Ob basin (Irtysh, Chulym, Ishim, Tobol, Ket and Konda) have a length of more than 1000 km; the length of even some second-order tributaries sometimes exceeds 500 km.

The largest of the tributaries - Irtysh, whose length is 4248 km. Its origins lie outside the Soviet Union, in the mountains of the Mongolian Altai. For a significant part of its turning, the Irtysh crosses the steppes of Northern Kazakhstan and has almost no tributaries right up to Omsk. Only in the lower reaches, already within the taiga, several large rivers flow into it: Ishim, Tobol, etc. The entire length of the Irtysh is navigable, but in the upper reaches in summer, during a period of low water level, navigation is difficult due to numerous rifts.

Along the eastern border of the West Siberian Plain flows Yenisei- the most abundant river in the Soviet Union. Her length is 4091 km(if we consider the Selenga River as the source, then 5940 km); the basin area is almost 2.6 million sq. km 2. Like the Ob, the Yenisei basin is elongated in the meridional direction. All its major right tributaries flow through the territory of the Central Siberian Plateau. From the flat swampy watersheds of the West Siberian Plain, only the shorter and less watery left tributaries of the Yenisei begin.

The Yenisei originates in the mountains of the Tuva ASSR. In the upper and middle reaches, where the river crosses the spurs of the Sayan Mountains and the Central Siberian Plateau, composed of bedrock, rapids (Kazachinsky, Osinovsky, etc.) occur in its channel. After the confluence of the Lower Tunguska, the current becomes calmer and slower, and sandy islands appear in the channel, breaking the river into channels. The Yenisei flows into the wide Yenisei Bay of the Kara Sea; its width near the mouth, located near the Brekhov Islands, reaches 20 km.

The Yenisei is characterized by large fluctuations in expenditure by season. Its minimum winter consumption near the mouth is about 2500 m 3 /sec, the maximum during the flood period exceeds 132 thousand km. m 3 /sec with an annual average of about 19,800 m 3 /sec. During the year, the river brings to its mouth more than 623 km 3 water. In the lower reaches, the depth of the Yenisei is very significant (in places 50 m). This makes it possible for sea vessels to rise up the river by more than 700 km and reach Igarka.

There are about one million lakes on the West Siberian Plain, the total area of which is more than 100 thousand hectares. km 2. According to the origin of the basins, they are divided into several groups: occupying the primary irregularities of the flat relief; thermokarst; moraine-glacial; lakes of river valleys, which in turn are divided into floodplain and oxbow lakes. Peculiar lakes - "fogs" - are found in the Ural part of the plain. They are located in wide valleys, flood in the spring, sharply reducing their size in the summer, and by autumn, many disappear altogether. In the forest-steppe and steppe regions of Western Siberia there are lakes that fill suffusion or tectonic basins.

Soils, vegetation and wildlife

The plain relief of Western Siberia contributes to a pronounced zonality in the distribution of soils and vegetation. Within the country there are tundra, forest-tundra, forest-bog, forest-steppe and steppe zones gradually replacing one another. Geographical zoning resembles, therefore, in in general terms zoning system of the Russian Plain. However, the zones of the West Siberian Plain also have a number of local specific features which noticeably distinguish them from similar zones in Eastern Europe. Typical zonal landscapes are located here on dissected and better drained upland and riverine areas. In poorly drained interfluve spaces, the runoff from which is difficult, and the soils are usually highly moistened, marsh landscapes prevail in the northern provinces, and landscapes formed under the influence of saline groundwater in the south. Thus, the nature and density of relief dissection play a much greater role here than on the Russian Plain in the distribution of soils and vegetation cover, causing significant differences in the regime of soil moisture.

Therefore, there are, as it were, two independent systems of latitudinal zonality in the country: the zonality of drained areas and the zonality of undrained interfluves. These differences are most clearly manifested in the nature of the soils. So, in the drained areas of the forest-bog zone, mainly strongly podzolized soils are formed under the coniferous taiga and soddy-podzolic soils under the birch forests, and in neighboring undrained places - thick podzols, marsh and meadow-bog soils. The drained spaces of the forest-steppe zone are mostly occupied by leached and degraded chernozems or dark gray podzolized soils under birch groves; in undrained areas, they are replaced by marsh, saline or meadow-chernozem soils. In the upland areas of the steppe zone, either ordinary chernozems, which are characterized by increased obesity, low thickness, and linguality (heterogeneity) of soil horizons, or chestnut soils predominate; in poorly drained areas, they usually include spots of solods and solodized solonetzes or solonetsous meadow-steppe soils.

Fragment of a section of swampy taiga in Surgut Polissya (according to V. I. Orlov)

There are some other features that distinguish the zones of Western Siberia from the zones of the Russian Plain. In the tundra zone, which extends much further north than on the Russian Plain, large areas are occupied by arctic tundra, which are absent in the mainland regions of the European part of the Union. The woody vegetation of the forest-tundra is represented mainly by Siberian larch, and not by spruce, as in the regions lying west of the Urals.

In the forest-bog zone, 60% of the area of which is occupied by swamps and poorly drained swampy forests 1, pine forests occupy 24.5% of the forested area, and birch forests (22.6%), mainly secondary ones, predominate. Smaller areas are covered with damp dark coniferous cedar taiga (Pinus sibirica), fir (Abies sibirica) and ate (Picea obovata). Broad-leaved species (with the exception of linden, occasionally found in the southern regions) are absent in the forests of Western Siberia, and therefore there is no zone of broad-leaved forests here.

1 It is for this reason that the zone in Western Siberia is called the forest-bog zone.

An increase in the continentality of the climate causes a relatively sharp transition, compared to the Russian Plain, from forest-bog landscapes to dry steppe spaces in the southern regions of the West Siberian Plain. Therefore, the width of the forest-steppe zone in Western Siberia is much less than on the Russian Plain, and of the tree species it contains mainly birch and aspen.

The West Siberian Plain is wholly part of the transitional Eurosiberian zoogeographic subregion of the Palearctic. 478 species of vertebrates are known here, of which 80 species are mammals. The fauna of the country is young and in its composition differs little from the fauna of the Russian Plain. Only in the eastern half of the country are some eastern, trans-Yenisei forms found: the Dzungarian hamster (Phodopus sungorus), chipmunk (Eutamias sibiricus) and others. In recent years, the fauna of Western Siberia has been enriched by muskrats acclimatized here (Ondatra zibethica), hare-hare (Lepus europaeus), American mink (Lutreola vison), teleutka squirrel (Sciurus vulgaris exalbidus), and carp were introduced into its reservoirs (Cyprinus carpio) and bream (Abramis brama).

Natural resources

The natural wealth of Western Siberia has long served as the basis for the development of various sectors of the economy. There are tens of millions of hectares of good arable land here. Particularly valuable are the lands of the steppe and forest-steppe zones with their climate favorable for agriculture and highly fertile chernozems, gray forest and non-saline chestnut soils, which occupy more than 10% of the country's area. Due to the flatness of the relief, the development of the lands of the southern part of Western Siberia does not require large capital expenditures. For this reason, they were one of the priority areas for the development of virgin and fallow lands; in recent years, more than 15 million hectares have been involved in crop rotation. ha new lands, the production of grain and industrial crops (sugar beet, sunflower, etc.) increased. The lands located to the north, even in the southern taiga zone, are still underused and are a good reserve for development in the coming years. However, this will require much greater expenditures of labor and funds for draining, uprooting and clearing land from shrubs.

The pastures of the forest-bog, forest-steppe and steppe zones are of high economic value, especially water meadows along the valleys of the Ob, Irtysh, Yenisei and their large tributaries. The abundance of natural meadows here creates a solid base for the further development of animal husbandry and a significant increase in its productivity. Moss pastures of the tundra and forest-tundra, occupying more than 20 million hectares in Western Siberia, are of great importance for the development of reindeer breeding. ha; more than half a million domestic deer graze on them.

A significant part of the plain is occupied by forests - birch, pine, cedar, fir, spruce and larch. The total forested area in Western Siberia exceeds 80 million hectares. ha; timber reserves of about 10 billion m 3, and its annual growth is over 10 million tons. m 3 . The most valuable forest areas are located here, which provide wood for various sectors of the national economy. The forests along the valleys of the Ob, the lower reaches of the Irtysh and some of their navigable or raftable tributaries are currently most widely used. But many forests, including especially valuable massifs of condo pine, located between the Urals and the Ob, are still poorly developed.

Dozens of large rivers of Western Siberia and hundreds of their tributaries serve as important shipping routes connecting the southern regions with the far north. The total length of navigable rivers exceeds 25,000 km. km. Approximately the same is the length of the rivers along which timber is rafted. The full-flowing rivers of the country (Yenisei, Ob, Irtysh, Tom, etc.) have large energy resources; if fully utilized, they could generate more than $200 billion. kWh electricity per year. The first large Novosibirsk hydroelectric power station on the Ob River with a capacity of 400,000 kWh. kW entered service in 1959; above it, a reservoir with an area of 1070 km 2. In the future, it is planned to build a hydroelectric power station on the Yenisei (Osinovskaya, Igarskaya), in the upper reaches of the Ob (Kamenskaya, Baturinskaya), on the Tom (Tomskaya).

The waters of the large West Siberian rivers can also be used for irrigation and watering of the semi-desert and desert regions of Kazakhstan and Central Asia, which are already experiencing a significant shortage of water resources. Currently, design organizations are developing the main provisions and a feasibility study for the transfer of part of the flow of Siberian rivers to the Aral Sea basin. According to preliminary studies, the implementation of the first stage of this project should provide an annual transfer of 25 km 3 waters from Western Siberia to Central Asia. To this end, on the Irtysh, near Tobolsk, it is planned to create a large reservoir. From it, to the south along the Tobol valley and along the Turgai depression into the Syrdarya basin, the Ob-Caspian canal, more than 1500 meters long, will go to the reservoirs created there. km. The rise of water to the Tobol-Aral watershed is supposed to be carried out by a system of powerful pumping stations.

At the next stages of the project, the volume of water transferred annually can be increased to 60-80 km 3 . Since the waters of the Irtysh and Tobol will no longer be enough for this, the work of the second stage involves the construction of dams and reservoirs on the upper Ob, and possibly on the Chulym and Yenisei.

Naturally, the withdrawal of tens of cubic kilometers of water from the Ob and Irtysh should affect the regime of these rivers in their middle and lower reaches, as well as changes in the landscapes of the territories adjacent to the projected reservoirs and transfer channels. Forecasting the nature of these changes now occupies a prominent place in the scientific research of Siberian geographers.

Until quite recently, many geologists, based on the idea of the uniformity of the thick strata of loose deposits that make up the plain and its apparent simplicity tectonic structure, very cautiously assessed the possibility of discovering any valuable minerals in its bowels. However, held in recent decades geological and geophysical studies, accompanied by the drilling of deep wells, showed the erroneousness of previous ideas about the poverty of the country in minerals and made it possible to imagine the prospects for the use of its mineral resources in a completely new way.

As a result of these studies, more than 120 oil fields have already been discovered in the strata of the Mesozoic (mainly Jurassic and Lower Cretaceous) deposits of the central regions of Western Siberia. The main oil-bearing areas are located in the Middle Ob region - in Nizhnevartovsk (including the Samotlor field, which can produce oil up to 100-120 million tons). t/year), Surgut (Ust-Balykskoe, Zapadno-Surgutskoe, etc.) and Yuzhno-Balyksky (Mamontovskoe, Pravdinskoe, etc.) districts. In addition, there are deposits in the Shaim region, in the Ural part of the plain.

In recent years, in the north of Western Siberia - in the lower reaches of the Ob, Taz and Yamal - the largest deposits of natural gas have also been discovered. The potential reserves of some of them (Urengoy, Medvezhye, Zapolyarny) amount to several trillion cubic meters; gas production at each can reach 75-100 billion cubic meters. m 3 per year. In general, the predicted gas reserves in the depths of Western Siberia are estimated at 40-50 trillion. m 3 , including categories A + B + C 1 - more than 10 trillion. m 3 .

Oil and gas fields of Western Siberia

The discovery of both oil and gas fields is of great importance for the development of the economy of Western Siberia and neighboring economic regions. The Tyumen and Tomsk regions are turning into important oil-producing, oil-refining and chemical industry. Already in 1975, more than 145 million tons of oil were mined here. t oil and tens of billions of cubic meters of gas. Oil pipelines Ust-Balyk - Omsk (965 km), Shaim - Tyumen (436 km), Samotlor - Ust-Balyk - Kurgan - Ufa - Almetyevsk, through which oil got out to European part USSR - to the places of its greatest consumption. For the same purpose, the Tyumen-Surgut railway and gas pipelines were built, through which natural gas from West Siberian deposits goes to the Urals, as well as to the central and northwestern regions of the European part of the Soviet Union. In the last five-year plan, the construction of the giant supergas pipeline Siberia - Moscow (its length is more than 3,000 km) was completed. km), through which gas from the Medvezhye field is supplied to Moscow. In the future, gas from Western Siberia will go through pipelines to the countries of Western Europe.

Brown coal deposits have also become known, confined to the Mesozoic and Neogene deposits of the marginal regions of the plain (North-Sosva, Yenisei-Chulym and Ob-Irtysh basins). Western Siberia also has colossal peat reserves. In its peatlands, the total area of which exceeds 36.5 million hectares. ha, concluded a little less than 90 billion. t air-dry peat. This is almost 60% of all peat resources of the USSR.

Geological research led to the discovery of the deposit and other minerals. In the southeast, in the Upper Cretaceous and Paleogene sandstones of the vicinity of Kolpashev and Bakchar, large deposits of oolitic iron ores have been discovered. They lie relatively shallow (150-400 m), the iron content in them is up to 36-45%, and the predicted geological reserves of the West Siberian iron ore basin are estimated at 300-350 billion tons. t, including in one Bakcharskoye field - 40 billion cubic meters. t. Numerous salt lakes in the south of Western Siberia contain hundreds of millions of tons of common and Glauber's salt, as well as tens of millions of tons of soda. In addition, Western Siberia has huge reserves of raw materials for the production of building materials (sand, clay, marls); on its western and southern outskirts there are deposits of limestones, granites, diabases.

Western Siberia is one of the most important economic and geographical regions of the USSR. About 14 million people live on its territory (the average population density is 5 people per 1 km 2) (1976). In cities and workers' settlements there are machine-building, oil refineries and chemical plants, enterprises of the timber, light and food industries. Various branches of agriculture are of great importance in the economy of Western Siberia. It produces about 20% of the commercial grain of the USSR, a significant amount of various industrial crops, a lot of butter, meat and wool.

The decisions of the 25th Congress of the CPSU outlined further gigantic growth in the economy of Western Siberia and a significant increase in its importance in the economy of our country. In the coming years, it is planned to create new energy bases within its borders based on the use of cheap coal deposits and hydropower resources of the Yenisei and Ob, develop the oil and gas industry, and create new centers of mechanical engineering and chemistry.

The main directions of development of the national economy plan to continue the formation of the West Siberian territorial production complex, to turn Western Siberia into the USSR's main oil and gas production base. In 1980, 300-310 million tons will be produced here. t oil and up to 125-155 billion m 3 natural gas (about 30% of gas production in our country).

It is planned to continue the construction of the Tomsk petrochemical complex, put into operation the first stage of the Achinsk oil refinery, expand the construction of the Tobolsk petrochemical complex, build plants for processing petroleum gas, a system of powerful pipelines for transporting oil and gas from the northwestern regions of Western Siberia to the European part of the USSR and to refineries eastern regions countries, as well as the Surgut-Nizhnevartovsk railway and begin construction of the Surgut-Urengoi railway. The tasks of the five-year plan provide for accelerating the exploration of oil, natural gas and condensate fields in the Middle Ob and in the north Tyumen region. The harvesting of timber, the production of grain and livestock products will also increase substantially. In the southern regions of the country, it is planned to carry out a number of major land reclamation measures - to irrigate and water large areas of land in the Kulunda and Irtysh regions, to begin construction of the second stage of the Aley system and the Charysh group water pipeline, and to build drainage systems in Baraba.

"of our website.

For a better understanding of what is written, see also " Dictionary of physical geography", which has the following sections:

The West Siberian lowland is a single physical-geographical region consisting of two flat bowl-shaped depressions, between which there are elevations elongated in the latitudinal direction (up to 175-200 m), orographically combined into Siberian ridges.

Almost from all sides the lowland is outlined by natural boundaries. In the west it is distinctly delimited by the eastern slopes of the Ural Mountains, in the north by the Kara Sea, in the east by the valley of the Yenisei River and the cliffs of the Central Siberian Plateau. Only in the south is the natural boundary less pronounced. Gradually rising, the plain passes here into the adjoining uplands of the Turgai plateau and the Kazakh hills.

The West Siberian lowland occupies about 2.25 million km 2 and has a length of 2500 km from north to south, and 1500 km from east to west (in the widest southern part). Exclusively flat terrain This territory is explained by the alignment of the complex-folded basement of the West Siberian Platform with a thick cover of Meso-Cenozoic deposits. During the Holocene period, the territory experienced repeated subsidence and was an area of accumulation of loose alluvial, lacustrine, and in the north - glacial and marine deposits, the thickness of which in the northern and central regions reaches 200-250 m. However, in the south, the thickness of Quaternary deposits drops to 5-10 m and in the modern relief, signs of the influence of neotectonic movements are clearly manifested.

The peculiarity of the paleogeographical situation lies in the strong watering of the territory inherited from the Holocene and the presence at present of a huge number of residual water bodies.

Large modern forms relief of Western Siberia are morphostructures created by the latest movements earth's crust. Positive morphostructures: uplands, plateaus, ridges - have a more dissected relief and better drainage. Dominant for the relief of the territory are negative morphostructures - plains covered with a thickness of loose layered deposits, often gleyed to a great depth. These properties worsen the water permeability of the strata and slow down the ground runoff.

The flatness of the territory determined the special nature of the hydrographic network: low water flow rates and significant tortuosity of the channels. The rivers of Western Siberia have a mixed supply - snow, rain, ground, with a predominance of the first. All rivers are characterized by a long spring flood, often turning into summer, which is explained by the different opening times of the rivers in various parts watersheds. Flood waters, spilling over many kilometers, are an important factor in the extremely high watering of watersheds, and rivers practically do not play their draining role during this period.

Thus, the combination of physical and geographical factors that favorably influence the bog-forming process determined the intensity of the formation and accumulation of huge peat reserves and the widespread distribution of peat deposits throughout the entire territory of the West Siberian Plain.

The vegetation cover of peat deposits in the West Siberian Lowland has not been studied in sufficient detail. The tree layer of forested peatlands here is much richer in species composition due to the species characteristic of the taiga forests of Siberia, such as cedar, fir, and larch. Usually, together with birch, spruce, and pine, they make up the forest stand of swamps in various combinations and quantities. Almost pure plantations of birch on peatlands are quite frequent and, under appropriate conditions, are found in all peat-bog regions of the West Siberian Lowland. On the lowland peatlands of the floodplains, pure willow thickets are noted.

In the shrub layer of the vegetation cover of the West Siberian swamps, such a representative of the Siberian flora as Salix sibirica is found, but the European species Calluna vulgaris is not reflected in it. Representatives of the Siberian flora were also noted in the grass layer: Carex wiluica, Cacalia hastata, Ligularia sibirica. Carex globularis, found in the European part of the Union as part of the vegetation of swampy spruce forests, has expanded its habitat in Western Siberia and is found in large numbers on typical high-moor peat bogs. sp. rubellum and Sph. cuspi datum, which are typical inhabitants of high-moor peatlands in the northwestern region of the European part of the Union, are rarely found in the moss cover of peatlands in the West Siberian Lowland. But in much greater numbers and in more southern latitudes, Sph. lindbergii and Sph. congstroemii, which are typical for the peatlands of the Arkhangelsk region and are rare in the peatlands of the middle zone. Sometimes Cladonia and Cetraria form continuous patches in the ridge-lake areas of the watershed peatlands of the Vasyugan region, and up to 12 species of Cladonia are found in this regenerative complex.

Of the plant phytocenoses of the West Siberian Lowland, it is necessary to note the grass-sedge phytocenosis, which covers large areas in the marginal areas of the lands (under conditions of some soil salinity). It includes reed grass (Scolochloa festucacea), reed grass (Calamagrostis neglecta), Carex omskiana, C. appropinquata and C. orthostachys. Peat bogs are characterized in the tree layer by birch (up to 15–20 m high) and conifers: spruce, cedar, pine, larch; in the undergrowth, along with willows (Salix sibirica, S. pentandra), blackcurrant, mountain ash, bird cherry; in the shrub layer - marsh myrtle, cranberries, blueberries, cloudberries. The herbage is rich in species and flourishes; C. caespitosa dominates in it, C. globularis, C. disperma are found among other sedges, and taiga plants (Equisetum silvaticum, Casalia hastata, Pyrola rolundifolia) grow in forbs along with marsh plants. Elements of the taiga flora are also noted in the moss cover: on hummocks of Sph. warnstorfii - Pleuroziumschreberi and Hylocomium splendens, in interhummock depressions - Thuidium recognitum, Helodium blandowii, on the slopes of hummocks - Climacium dendroides. Iron efflorescences can often be observed in the depressions between the bumps in the sogres.

Most often, the edge areas of low-lying marshy swamps of the floodplain terraces along the channels of the Ob, Irtysh, Chulym, Keti, and Tyma rivers are covered with sorams. From the outside, they gradually turn into swampy forests, towards the center of the peat bog - into a forest complex phytocenosis.

In the West Siberian Plain, borrowings predominate in the Ishim peat-bog region on the interfluve of the Ishim and Tobol in their middle reaches. Here they adjoin lakes or surround them with a continuous ring. Huge areas are sometimes occupied by borrowings in lowlands, no longer connected with lakes, but bearing the features of former channels between lakes.

Zaimishchno-ryam peatlands are often found in the eastern part of the South Baraba peat-bog region, where they are confined to lakes or flat depressions in which surface waters stagnate for a long time. Among the loans scattered raised raised peat bogs, occupying a small area compared to the loans. These are well-known "ryams". During the growing season, a variable water and mineral regime is created in the lands: in spring and in the first half of summer they are flooded with fresh deluvial melt waters, and often river hollow; in the second half of the growing season, the loans on a larger peripheral area dry up, and here there are favorable conditions for capillary rise to the surface of saline soil-ground waters and on the surface, efflorescences of salts (Ca, Cl and SO 3) are usually observed.

The area of the loan can be subdivided into: a zone of constant moisture with respect to fresh water(the central part of the loan, the shores of lakes and river channels) and a zone of variable moisture, where both the degree of watering and the degree of mineralization of the supply waters are variable (peripheral parts of the loans).

The central parts of the borrowings are covered with reed phytocenosis, in which the main background plants are reed, reed (Scolochloa festucacea), reed grass, sedges (C. caespitosa and C. wiluica). As an admixture, the phytocenosis includes Carex omskiana, C. buxbaumii, watch, bedstraw (Galium uliginosum). Among the components of the reed phytocenosis, reed, reed grass, Carex caespitosa and C. buxbaumii are salt-tolerant plants.

In the zone of borrowings where constant moisture begins to give way to variable moisture, under conditions of some salinity of the substrate, gradual thinning of reed beds and the introduction of sedges (C. diandra, C. pseudocyperus), cattail and reed grass are observed. The sedge-reed phytocenosis is characterized by scattered scattered birch (B. pubescens) and willow (S. cinerea) bushes.

Along the periphery of the borrowings in the zone of variable moistening, reedweed (Scolochloa, festucacea), which under the conditions of Baraba is an indicator of mixed chloride-sulfate salinization, displaces reed grass from the vegetation cover, and here a grass-sedge phytocenosis arises mainly from reedweed, Carex omskiana, C. appropinquata and C. orthostachys with a small contribution of the same reed.

The formation and development of ryams (oligotrophic pine-shrub-sphagnum islands) occurs in isolation from saline soils in both horizontal and vertical directions. Isolation in the horizontal direction is the deposit of loans; isolation in the vertical direction is a layer of reed peat with an average degree of decomposition of 22-23%, underlying the upper ryam deposit. The thickness of the reed peat is 0.5-1.5 m, the thickness of the upper fallow is 0.5-1 m. The stumpiness of the sphagnum deposit is low and decreases from the upper layers to the lower ones.

The surface of the ryam is sharply convex with asymmetrical slopes. Under the pine tree layer, there is a shrub layer and a moss cover of Sph. fuscum with admixture of Sph. angustifolium and Sph. magellanicum.

The largest ryams up to 1000-1500 ha (Big Ubinsky and Nuskovsky) are found in the northern and middle parts forest-steppe zones. Usually the area of ryams is 100-400 ha, sometimes 4-5 ha (small ryams of the Chulym region).

The peat deposits of Western Siberia are extremely diverse in terms of the conditions of formation and development, the qualitative and quantitative indicators of the deposit, vegetation cover, the nature of distribution and other factors, in the change of which there is a fairly clear pattern closely related to natural latitudinal zonality. According to this principle, 15 peat-bog areas have been identified on the territory of Western Siberia.

The extreme north of the West Siberian Lowland occupies area of arctic mineral sedge bogs. It geographically corresponds to the West Siberian subzone of the Arctic tundra. The total swampiness of this territory is almost 50%, which is a consequence of the water-resistant frozen layer located close to the surface, the excess of precipitation over evaporation and the flatness of the country. The thickness of the peat layer does not exceed a few centimeters. Deeply deposited peatlands should be classified as relics of the Holocene climatic optimum. Polygonal and even moss-sedge bogs are common here.

Noteworthy is the wide distribution of eutrophic moss-sedge bogs with a flat surface (up to 20-25% of the total area). It is dominated by Carex stans or Eriophorum angustifolium with a mossy carpet of Calliergon sarmentosum and Drepanocladus revolvens.

In the river valleys among the sedge marshes there are mounds covered with Sph. warnstorfii, Sph. lenense, Dicranum elongatum and lichens. Of the flowering plants, thickets of Betula nana and Rubus chamaemorus are abundant.

Along the shores of the bays and the Kara Sea, there are coastal swamps flooded with surge winds. sea water. These are largely brackish bogs with grasses (Dupontia fisonera), sedges (Carex rariflora, etc.) and Stellaria humifusa.

The moss tundra is especially characterized by the abundance of Eriophorum angustifolium on the moss cover of Aulacomnium turgidium, Camptothecium trichoides, Aulacomnium proliferum, Dicranum elongatum, Ptilium ciliare. Sometimes sedges (Carex stans, Carex rotundata) with a similar composition of moss cover and the participation of sphagnum mosses predominate in the swampy tundra.

South is located area of flat bogs. This zone geographically corresponds to the tundra. The swampiness of the zone is high (about 50%).

Flat-hilly peatlands represent a mosaic complex of hillocks and hollows. The height of the hillocks ranges from 30 to 50 cm, rarely reaches 70 cm. The area of the hillocks is up to several tens, less often hundreds of square meters. The shape of the mounds is lobed, round, oval, elongated or ridge-like, the tops of the mounds are occupied by lichens, mainly Cladonia milis and Cladonia rangiferina. Less common are Cetraria nivalis, C. cucullata, Cladonia amanrocraea. The slopes of the mounds are covered with green mosses. Abundant are Aulacomnium turgidium, Polytrichum strictum, Dicranum elongatum. Of the flowering plants, strongly oppressed Ledum palustre and Rubus chamaemorus grow in clusters. Between them are fragments of dicrane-lichen associations. Hollows are heavily watered with a continuous carpet of sphagnum mosses from Sph. lindbergii, Sph. balticum, Sph. subsecundum, Sph. Jensenii. Less commonly, Drepanocladus vernicosus, Drepanocladus fluitans are found in the hollows; Along with marshes, swampy areas are widespread, which are swampy shrub tundra with Betula papa and willows, sometimes with Ledum palustre, swampy moss tundra with Betula papa and Ledum palustre, tussock tundra with Eriophorum vaginatum.

Area of large-hilly swamps occupies the northern part of the forest zone and the southern forest-tundra. The swampiness of the zone is high. The hillocks are found singly, but more often they are located in groups or ridges 1-2 km long, up to 200 m wide. Single hillocks have a height of 2-2.5 m, soil hillocks 3-5 m, hillocks of the ridges reach a height of 8-10 m. Diameter bases of mounds 30-80 m, steep slopes (10-20°). Elongated depressions between hillocks are occupied by cottongrass-sphagnum and sedge-sphagnum oligotrophic or eutrophic hollows, sometimes with small lakes in the center. The surface of the largest mounds is broken by cracks up to 0.2-0.3 m deep. At the base of the mounds, sphagnum mosses grow and a layer of shrubs is developed, mainly Betula papa. Higher up the slope, lichens predominate. They are also characteristic of flat tops, which are often subjected to wind erosion.

Hilly peatlands are composed of peat up to 0.6 m thick on top, under which lies a highly ice-saturated mineral core, consisting of ice and loamy, silt-loamy, less often sandy material. The mineral core, in addition to ice-cement and its individual crystals, contains numerous ice interlayers, the thickness of which reaches several tens of centimeters and usually increases downwards, the number of interlayers also decreases downwards.

North Ob peat-bog region It is a poorly drained lacustrine-alluvial plain composed of medium- and fine-grained sands with a distinct horizontal layering.

The area is characterized by extremely high waterlogging. Peat deposits occupy more than 80% of the territory; form complex systems, covering flat interfluves and high river terraces. Raised convex heavily watered sphagnum peatlands dominate with ridge-lake complexes on flat tops and ridge-lake-hollow complexes on their slopes.

Areas with well-drained peatlands are insignificant and confined to the territory with the highest surface elevations. Fuscum and pine-sphagnum phytocenoses with a large number of various lichens are common here.

Lowland peat deposits are located mainly on the first floodplain terraces of large rivers.

The deposits of raised peatlands are shallow, on average about 2 m. slightly decomposed fuscum, complex, hollow types of structure predominate.

Kondinsky peat-bog area It is a vast alluvial and lacustrine-alluvial plain composed of layered sandy and clay deposits. For the left bank of the river The presence of a ridged relief is characteristic of the Konda and the right bank of its lower reaches. The area is characterized by extremely high watering. A significant part of the Kondinsky region is confined to the area of intense tectonic subsidence and, therefore, is characterized by the predominance of accumulation processes and the dominance of poorly drained swamps. Only West Side areas where denudation processes predominate are characterized by low waterlogging. The riverbeds are slightly incised. In the spring hollow waters these rivers overflow widely and do not enter the banks for a long time. Therefore, the river valleys are swampy for a long distance; near-terrace swamps are strongly flooded during floods. For the river basin Konda is characterized by the predominance of raised ridge-lake, ridge-lake-hollow and ridge-hollow peat deposits.

Lowland, sedge, reed, reed grass, birch-reed grass peatlands are confined to river beds.

Transitional sedge-sphagnum, tree-sphagnum and sphagnum bogs are found along low terraces and in places where they are articulated into bog systems. There are also complexes that form along the lines of the surface intrafallow runoff of swamp waters.

The gradual tectonic subsidence of the surface affects the extremely high watering of the territory, which contributes to the intensive development of regressive phenomena in the swamps, the destruction of the sphagnum sod of ridges, hollows, an increase in the area of hollows due to the degradation of ridges, etc.

Among the swamps there are a huge number of lakes. Some of them are completely covered with peat, but most of them have preserved an open water surface among peaty shores.

In the river basin Kondy, the main type of peat deposit is raised, which is dominated by a complex type of structure, which is due to the dominance of ridge-hollow complexes. Fuscum, Scheuchzerium-sphagnum and Magellanicum deposits are somewhat less common.

Transitional types of deposits compose peat bogs mainly of the second terrace of the river. Konda and its tributaries, and also occur along the edges of upland peat deposits, around mineral islands, or are confined to mesotrophic grass and moss swamps. The most common type of deposit is transitional fens.

Low-lying deposits are found in floodplains, forming narrow strips confined to the overgrown rivers of raised bogs.

The analysis of spore-pollen diagrams dates the Konda peatlands to the Early Holocene. The peat bogs have an ancient Holocene age, the deposit depth of which exceeds 6 m.

Middle Ob peat-bog region It is a lacustrine-alluvial and alluvial plain composed from the surface mainly of cover deposits underlain by either lacustrine layered clays or light loams, siltstone and sandy strata.

The territory is characterized by the development of progressive and predominant accumulation processes, which determines the predominant distribution of poorly drained swamps and constantly swampy forests. Only in the north of the region, where denudation processes predominate, are relatively drained swamps found.

The area is characterized by the dominance of raised sphagnum bogs with ridge-lake-hollow and ridge-hollow complexes. Marsh margins located at lower hypsometric levels (within the first floodplain terraces and floodplains of small lakes) are usually eutrophic or mesotrophic. The deposit of their central parts is represented by fuscum and complex types of structure and has a depth of 4-6 m.

Large peatlands on the watersheds of the first order are divided into three categories. On flat, level plateaus of watersheds, peatlands have a strongly convex surface with steep slopes and a flat central part. The difference in the levels of the center and edges is 4-6 m. The central main part of such peatlands is represented by a fuscum-deposit or complex upland and bears on the surface lake-denudation or ridge-lake vegetation complexes, and on the slopes - ridge-hollow.

On one-sidedly elevated watersheds with a gently concave asymmetric surface, high-moor peatlands show a drop in surface marks from an elevated slope to a lower one.

The thickness of the peat layer also decreases in the same direction. The deepest part of such peatlands is usually represented by a fuscum-type structure with a ridge-lake complex of vegetation on the surface. In the direction to the opposite slope of the watershed, the fallow passes into a complex upland one with a ridge-hollow complex in the vegetation cover. A shallow peripheral area with a transitional marsh deposit bears the vegetation of sphagnum marshes on the surface.

On symmetrical watersheds with a flat plateau, sometimes high-moor peatlands with a complex surface line are observed: two evenly elevated caps are separated by a trough up to 2-3 m deep. Such peatlands are composed mainly of high-moor fuscum or complex peat. Vegetation cover on the gangs is represented by a ridge-lake complex, in the area of the trough - by sphagnum swamps, often giving rise to rivers. A. Ya. Bronzov explains the formation of such massifs by the confluence of two (sometimes several) peat bogs with separate swamping centers. In some cases, the formation of a trough could occur as a result of the breakthrough and outpouring of intradeposit waters and partially the most liquefied and plastic peats from the peat bog, followed by subsidence of the peat deposit.

On watersheds of the second order, peatlands occupy interfluves that have undergone significant dissection. The depth of the erosion incision here reaches 20-30 m. This is the nature of the watersheds between large rivers, flowing approximately parallel to each other in their middle reaches.

In upland conditions, on the watersheds of the occurrence, there are large peat deposits of the raised type with a predominance of fuscum deposits and with ridge-lake and ridge-hollow complexes of vegetation on the surface.

Basically, the Middle Ob region, as well as the Vasyugan region located to the south, are territories of almost continuous swampiness. The swamps here completely cover the watersheds of the first and second orders, terraces and floodplains. High-moor peatlands predominate, the total area of which is about 90%.

Tym-Vakh peat-bog region occupies the Tym-Vakh interfluve and is composed of lacustrine-alluvial deposits. AT geographically it is confined to the Middle Vakh Plain and is characterized by high swampiness, which drops sharply in the northeastern part, where surface elevations reach 140 m.

Poorly drained raised sphagnum bogs with ridge-hollow-lake and ridge-hollow complexes dominate watersheds and fourth terraces. They are also found on low terraces and are confined to the hollows of the ancient runoff, where accumulation processes predominate. The deposit is characterized by great homogeneity and is composed of complex high-moor, Scheuchzerian and Fuscum peat.

The deposit of transitional swamps is represented by transitional marshes and forest-marsh types of structure. Lowland peatlands are rare and are confined mainly to floodplains and low terraces. The deposit of lowland bogs is composed of sedge peat.

Ket-Tymskaya peat-bog region occupies the interfluve of the Keti and Tym and extends east to the Yenisei. The watershed of the Ob and Yenisei has a clearly pronounced slope here with an increase in surface elevations to the east. The interfluves are composed of lacustrine-alluvial and deluvial deposits and are divided by a highly developed hydrographic network into a large number of small interfluves.

Due to the fact that the area is located within the contour of positive structures, the predominance of denudation processes causes the spread of well-drained swamps here. Regressive phenomena are less pronounced, there is a tendency for transgression of ridges, or ridges and hollows are in a state of dynamic equilibrium. The surface of the interfluve plateau has a clearly expressed crested relief. In some places, the dissected relief is leveled by a peat deposit 2-6 m deep fuscum - or a complex type of structure on the ridges, and in depressions - a transitional marsh or mixed marsh deposit with a lower horizon of lowland sedge peat 1.5 m thick. Some ridges are manes, towering above a peat deposit that fills depressions between ridges by 2-10 m. The width of ridges is up to 5 km. They are composed of sandy deposits and are usually overgrown with taiga forests of pine, fir, cedar, and birch. The peatlands of the depressions between ridges are represented by transitional marsh and mixed marsh types of structure. On the upper part of the slope of the watershed to the floodplain in the lower reaches of the Keti and Tyma rivers, there are frequent small rounded peatlands of suffusion depressions (from 10 to 100 ha, rarely more) with transitional and upland, less often with low-lying deposits.

The slopes of the watersheds are eroded, weakly dissected or almost undivided by ledges of terraces, covered with a cloak-like peat deposit, forming large peat bogs that stretch for long distances along the course of both rivers. Closer to the bottom of the watershed, these peatlands are composed of a low-lying deposit, higher up the slope - transitional, and in the upper parts of the slope - upland. Rather large lakes with sapropel deposits at the base are scattered on them, more often in the upper part of the slope, among the upper deposits.

In the upper reaches of the Keti and Tyma rivers, narrow terraces of both river valleys are covered with peat. Narrow peatlands stretched along the rivers are more often composed of transitional deposits. Raised slightly watered pine-shrub-sphagnum bogs are confined here to the watershed plain. The ridge-hollow complex is developed in the central parts of the largest peat bogs.

Lowland and transitional swamps are widespread on the first and partially on the second terraces of the river. Obi. Especially a lot of mesotrophic and eutrophic sedge, sedge-sphagnum, sedge-hypnum, tree-sedge bogs are found on the right-bank terraces of the river. Ob, between the rivers Ketyu and Tym. The average thickness of raised bogs is 3-5 m, lowland 2-4 m. Raised bogs are composed of fuscum, complex and Scheuchzeria-sphagnum types of structure. The deposit of mesotrophic swamps is represented by transitional marsh and forest-marsh types of structure. The deposit of lowland bogs is composed of sedge peat.

In the modern vegetation cover of swamps with a transitional deposit, one can observe an admixture of oligotrophic species, indicating the transition of peat formation to the stage of the oligotrophic type.

A feature of the Ket-Tym region is the significant distribution of transitional and low-lying peatlands in comparison with other peat-bog areas of the forest zone, where the dominants are exclusively raised bogs.

Tavda peat-bog region It is a flat, in some places gently undulating plain, composed of lacustrine-alluvial and alluvial sandy-loamy deposits.

Geographically, its central part is confined to the southern half of the Khanty-Mansiysk lowland, where accumulation processes predominate and the greatest swampiness takes place. In the northwestern outskirts, it enters the limits of the Tavdo-Konda Upland, and in the south - the Tobol-Ishim Plain. The swampiness of the area is high. A significant area is occupied by poorly drained lowland peat deposits, the deposit of which is composed mainly of sedge and sedge-hypnum types of structure with a small participation of deposits of forest-marsh and forest subtypes. The thickness of the deposits is small (2-4 m), occasionally there are peat deposits with a depth of 5 m. On flat watersheds, small raised-type peat bogs are common with deposits 6-7 m thick, often composed of peat of a low degree of decomposition almost to the mineral ground fuscum. There are many lakes on the surface of peat deposits, which at one time served as the centers of formation of the majority of peat deposits in the region.

Vasyugan peat-bog region is a vast, slightly elevated plain, experiencing tectonic uplift. It is composed of alluvial and subaerial sandy-loamy deposits. In the north and east of the region, lacustrine-alluvial deposits are widespread; in the south, subaerial loess-like loams enter its limits. The confinement of the area to the contours of positive structures determines the distribution of relatively drained swamps. Weakly drained swamps occupy the Demyan-Irtysh interfluve and depressions of the Ob-Irtysh watershed, where accumulation processes are developed.

In general, the area is characterized by high swampiness (up to 70%), especially its western part, where swampiness reaches 80% in some places.

Raised sphagnum bogs with ridge-hollow-lake and ridge-hollow complexes are confined to the flat tops of the watersheds. The slopes are less swampy. From the periphery, watershed raised sphagnum bogs are bordered by transitional sphagnum, grass-sphagnum areas of bogs. The deposit of raised bogs is composed of fuscum, complex, hollow and Scheuchzerian types of peat. The stratigraphy of lowland and transitional bogs is dominated by sedge and woody-herbal peat species.

In the middle part of the watersheds, low-lying slope deposits occur in very flat depressions. They are moistened by groundwater such as perched water from higher sections of the watersheds. At the base of the peatlands lie deoxidized silty calcareous loams, enriching the deposit with a significant amount of mineral salts. The nature of the vegetation cover indicates that a hard water regime is currently taking place. The peatbog deposit is represented by sedge-hypnum and hypnum types of structure. The thickness of the deposit is from 1.5 to 4.5 m.

Their areas are small, and they alternate with areas of sedge and swamp type of structure with a deposit depth of 1 to 3.5 m. types of structure with a deposit thickness of 1 to 2.8 m.

Upland areas in the form of islands lie among the low-lying deposits. Their peat stratum is represented mainly by the fuscum type of structure and reaches a thickness of 6 m. The world's largest watershed heterogeneous peat deposit "Vasyuganskoye" with an area of over 5 million hectares is located in the region. Lowland peatlands do not form at all in the area large areas and in addition to the slopes of the watersheds, they occupy mainly elongated sections in river valleys.

Low-lying sedge-hypnum bogs predominate on low terraces, which are heavily waterlogged, while low-lying and transitional woody-sphagnum, woody-herbaceous bogs develop in the terraced part. The floodplains are swamped mainly in the upper reaches of the rivers, where low-lying sedge, sedge-willow, tree-sedge and forest bogs are formed. In their canopy under birch canopy, Carex caespitosa and C. wiluica form high tussocks; there is a large amount of forbs in the depressions between tussocks.

Transitional type deposits are located either at the contact of upland deposits with wetland forests, or at the contact of upland and lowland areas. In both cases, these are most often heavily watered deposits with a thin peat layer (1.5–2 m) and vegetation cover of herbaceous plants (Carex lasiocarpa, C. rostrata, Scheuchzeria palustris) and hydrophilic sphagnum mosses (Sph obtusum, Sph. majus, Sph. fallax, Sph. jensenii), forming a smooth semi-submerged carpet.

The thickness of the peat layer in floodplain peatlands does not exceed 1.5-2 m. Their deposit of sedge, Scheuchzeria, wood-sedge or birch peat was in conditions of variable moisture with the participation of river waters, therefore its ash content is relatively increased.

Vasyugan region is characterized by intensive peat accumulation. The average thickness of peat deposits is 4-5 m. Their age dates back to the early Holocene. The areas of swamps up to 8 m deep have the Old Holocene age.

Ket-Chulym peat-bog area characterized by less peatiness compared to the Ket-Tymskaya, which finds its explanation in the geomorphological features of the area. The watershed Ket-Chulym plateau has a much greater degree of erosional dissection under the influence of the main water arteries. The rivers here cut deeply into the surface of the watersheds and have well-formed but narrow alluvial terraces. This caused a decrease in groundwater. Therefore, the total peat content in the Ket-Chulym region is reduced to 10%.

The relief of the watershed Ket-Chulym plateau is characterized by small saucer-shaped depressions of suffusion origin. They predetermine here basically

location and type of peatlands. The most widespread in peat bogs of suffusion depressions is the transitional marsh deposit with a total thickness of the peat layer from 1 to 4.5 m. Raised deposits are less common in them, mainly fuscum, complex and Scheuchzeria-sphagnum with a depth of up to 3-6 m. 1-2 m deep are occupied by cottongrass-sphagnum or Magellanicum-deposit. Lowland deposits in suffusion depressions are rare and are represented by forest, tree-sedge, multilayer forest-marsh and sedge types of structure. They fill the deepest hollows, in which the thickness of the peat suite reaches 4-5 m.

In the Ket-Chulym region, there is a certain regularity in the placement of near-terrace peat deposits. In the middle part of the river Ulu-Yul peatlands are small and located on sharply defined terraces. Downstream the river, the terrace ledges are smoothed out, the surfaces of the terraces are expanding, and the areas of peat deposits are also increasing. The latter acquire an elongated shape and are extended parallel to the river. Near the mouth of the river Ulu-Yul terraces are even weaker and peat deposits merge with each other, covering the surface of several terraces.

On terraces and in the terraced parts of river valleys, peat bogs are smaller in size (in comparison with peat bogs in the Ket-Tym region) and, without merging into massifs long distance, form on the terraces chains of disconnected deep-lying peat deposits extended parallel to the river, often of a low-lying type with forest, tree-sedge or sedge deposits.

Tura-Ishim peat-bog area is a lacustrine-alluvial plain composed of sandy-loamy deposits and is characterized by the predominance of denudation processes. The swampiness of the region is high. Lowland bogs dominate: sedge, sedge-hypnum, birch-sedge. Raised pine-sphagnum bogs occupy insignificant areas. The most waterlogged central parts of the interfluve are occupied by raised ridge-hollow bogs.

In general, this area is highly swampy, slightly dissected, gently flat, wide river valleys with large low-lying sedge-hypnum bogs at the foot of the terraces and along their slopes, and with medium-sized high-moor and transitional peat bogs on the watersheds. The total swampiness of the region is up to 40%.

An example of a peat deposit of the first floodplain terraces is Tarmanskoye, located in the valley of the river. Tours. It stretches along the river for up to 80 km and adjoins the ledge of the bedrock bank. Its deposit is almost entirely composed of sedge-hypnum and sedge peat, confirming the existence of subsoil nutrition.

The deposit includes within its boundaries a significant number of primary lakes of a rounded-elongated shape with an emerging orientation along the terrace. At the base of the lakes there are highly mineralized sapropels, which indicates the forest-steppe conditions during the formation of the lakes. In the lower horizons of the deposit or on the margins of the deposit, a high ash content of peat is observed as a result of clogging of the deposit with deluvial drifts.

North Baraba peat-bog area watershed sedge-hypnum bogs in the north borders on the Vasyugan peat-bog region, in the south on the South Baraba and is a gently undulating, slightly dissected plain. The region is composed of loess-like loams. The porosity is small. It is dominated by medium-sized low-lying peatlands of the type of borrowings with an area of 10 to 100 ha. The eastern margin, confined to the positive contours of the structures, is characterized by the development of relatively well-drained swamps. More than half of the peaty area is low-lying peatlands (54%) and about 27% is raised; the percentage of transitional peatlands is relatively high here (19%).

There are many lakes, depressions and peat deposits in the central part of the region. In the western part of the region, on the slopes of the Tara-Tartas interfluve, the main area of sedge-hypnum bogs is concentrated. Hypnum swamps develop in low relief elements, mainly in the places where ground hard water flows emerge, along the slopes of watersheds or in the terraced parts of river valleys. Therefore, a slightly increased ash content (up to 8-12%) is inherent in hypnum peat and peat deposits. The ash content of some terraced hypnum peatlands averages 6-7%. The ash content of the sedge-hypnum peat bogs of the Tara-Tartas interfluve is also measured by the same percentage.

To the east, sedge-hypnum peatlands yield their leading position in the lowland type to forest-marsh and forest deposits. The latter are located here along the edges of peat deposits, in the central sections of which, as well as in areas with a more elevated bottom relief, there are islands of upland deposits. Moreover, the fuscum fallow is usually peripheral in relation to the complex upland, which is located in the center, carrying a ridge-lake complex of vegetation on the surface.

Despite the increased carbonate content of the underlying rocks, the relatively low occurrence of groundwater, atmospheric precipitation, and partial uplift of the territory create favorable conditions for the gradual transition of lowland bogs to the oligotrophic stage of development. In the river valleys immediately adjacent to the river ridges, the richest in floristic composition woody-grass bogs (sogry) are common. In that part of the valley where anoxic groundwater flows and deluvial waters do not penetrate, sedge-hypnum bogs are formed. In addition to typical moss, there are sedge and sedge-grass bogs, and in the east - reed bogs, characteristic of the grass bogs zone.

In the riverine parts of the watersheds, along the banks of the upper reaches of the rivers, in the depressions of the terraces, transitional forest swamps are widespread. Watershed lowland sedge-hypnum and hypnum bogs usually have a simple structure and are composed of sedge-hypnum and sedge peat species. The presence of ryams (upper sphagnum islands) salient feature sedge-hypnum bogs of the North Baraba region. The hypnum deposit is more characteristic of swamps of low terraces, where soluble calcium salts predominate in water and mineral nutrition. The bog deposit of the watershed plains differs from the peat bog deposit of low terraces in terms of high rates of decomposition and ash content, which has a more complex stratigraphy. There are grass-hypnum, cottongrass-sedge, reed-sedge, reed-sedge, sedge-sphagnum types of peat.

The bottom layers of the deposit are usually composed of reed or sedge-reed types of structure. Peat species of the woody group take a significant part in the structure of the deposit of lowland near-terrace and floodplain-terrace bogs. Transitional forest swamps are widespread. They are formed in the interfluves, in the terraces above the floodplains and in the terraced parts. The deposit of these swamps is represented by transitional forest and forest-marsh types of structure.

In the pits, the upper horizons of the deposit (up to 2-4 m) are represented by fuscum-peat with separate layers of magellanicum, angustifolium, cotton grass-sphagnum, pine-cotton grass and pine-shrub peat species. The bottom layers of the deposit are usually represented by peat of transitional and lowland types. The average depth of the peat deposit on the watersheds is 2-3 m; on low terraces, the peat thickness increases to 5 m compared to the Vasyugan region. The beginning of the peat-forming process dates back to the early Holocene.

Tobol-Ishim peat-bog area located west of the river. Irtysh and crosses the interfluve of Ishim and Tobol in the middle reaches. The surface of the territory is quite dissected and well-drained. The swampiness of the region does not exceed 3%. It is dominated by small low-lying swamps of the type of borrowings with an area of 10 to 100 hectares. The confinement to the positive contours of the structures determines the development of predominantly well-drained peat deposits here.

The hryvnia nature of the relief, a poorly developed hydrographic network, a waterproof horizon close to the surface, and a slow runoff of surface waters led to the formation of a huge number of lakes, usually round or oval, with shallow depths, a flat bottom and strong overgrowth, in the spaces between the hryvnias. The lakes are often adjoined or surrounded by small-sized shallow sedge-reed bogs-bogs. During the period of snowmelt, the lakes are flooded with melt water, turning into temporary shallow water bodies, often interconnected, and then the flow through such a chain of lakes connected by lakes has the character of a river. There are very few isolated lakes. According to the chemical composition of the waters of the lakes, sometimes located in close proximity to one another, they are distinguished by considerable diversity. Nearby lie salty, bitter and fresh lakes.

Relatively larger occupants typical of the northern part of the region are surrounded by lakes with fresh and brackish water. The thickness of these deposits is up to 1-1.5 m. It is composed of highly mineralized sedge, sedge-reed and reed peat with an average ash content of 20-30%. Their vegetation cover is dominated by reed, reed-sedge and sedge (C. caespitosa, C. omskiana) phytocenoses.

Less large-sized borrowings are common in the southern part of the region around salt lakes. They are very shallow, composed of reed peat with a high degree of decomposition and high ash content. The reed association, less often the sedge association, dominates in their vegetation cover.

In the sandy expanses of the Tobol region and in the northern part of the region on the right bank of the Ishim, lowland peatlands (sedge and sedge-hypnum) have separate sections(like ryams) with upland fallows composed of fuscum-peat of a low degree of decomposition, with a convex surface and a secondary vegetation cover of pine-shrub phytocenosis, formed as a result of repeated fires.

In small basins of suffosis of ionic origin, there are shallow "chopping" peat bogs of the lowland type. They developed in solonetz microrelief depressions - "saucers". Salinization and the subsequent process of bogging leads to the appearance in them of areas that are exclusively characteristic of this area of marshy meadows with Carex intermedia, which are subsequently covered with thickets of shrubs, mainly Salix sibirica, and birch stands.

There are also treeless "choppy" swamps with sedge hummocks on the surface, surrounded by tall birch along the periphery. They formed in deeper and more humid depressions with diverse wetland vegetation, which varies greatly in composition in some cases: with tussocks of Carex omskiana, sometimes with Salix sibirica in the shrub layer. Such peatlands are never covered by birch over the entire area; the deposit in them is tree-sedge.

South Baraba peat-bog region large peat-ryam bogs are composed of alluvial-lacustrine and loess-like deposits. Its soil cover is dominated by peat-bog soils, solonetzes and solonchaks (up to 60%); a smaller area is occupied by chernozems, podzolic soils, etc.

The processes of salinization of soils (including peat ones) are widely manifested in the region. Their mineralization naturally increases from north to south. The general calm relief of the region is complicated by low ridges elongated in a southwestern direction in combination with depressions between ridges. The hydrographic network is quite dense. Both lakes and river beds are abundantly overgrown with aquatic and wetland vegetation and imperceptibly merge with wetlands. Very often, depressions between ridges are completely swamped. The relief of Baraba is characterized by suffusion depressions on various surface elements and a large number of lakes, different in size, origin and chemical composition of water.

The swampiness of the area is approximately 33%. Low-lying reed-sedge peatlands predominate here, accounting for up to 85% of the total wetland area. The remaining 15% is distributed between the upper deposits of the ryams and the transitional deposits of their peripheral areas.

Zaimishchno-ryam peat bogs are most common in the eastern half of the region, their area reaches several thousand hectares here, and the area of ryams - high, rising up to 8-10 m above the level of the occupant - up to a thousand hectares. In the direction to the west, the areas of borrowings decrease, ryams are less common, their height decreases.

The occurrence of high-lying deposits of ryams among the lowland deposits is associated with the feeding of ryam sites with fresh and slightly saline lacustrine or surface stagnant waters. The lakes are still preserved as open reservoirs adjacent to the ryams, sometimes traces of them remain at the base of the ryam deposits in the form of a thin layer of sapropel.

The degree of decomposition of borrowing peat, as a rule, exceeds the species index (30-50%), the average ash content is 20%. The deposit of borrowings is composed of highly mineralized peats of the marsh group: reed, reed-sedge and herbaceous (with a predominance of remains of svetluka and reed grass in the fiber). The total thickness of the borrowing deposits reaches 1.5 m. In the vegetation cover, reed, sedge-reed and sedge (or grass-sedge) phytocenoses are successively replaced in the direction from the center to the periphery. The latter borders on solonchak meadow vegetation. The areas fed by lake waters did not feel any variability in moisture and salt regime. Protected from the influence of saline groundwater by the low-lying deposits surrounding them, they were overgrown with Sph. teres, water bodies passed into the stage of a peat bog, gradually, as the deposits increased, they got out of the influence of lake waters and continued to develop as peat bogs of atmospheric nutrition. The dominance of Sph. fuscum maintains a regime of high humidity and low temperature in the deposit. sp. fuscum created its own substrate and microclimate even in forest-steppe conditions, and over the course of millennia it deposited powerful deposits of high-moor peat.

The modern vegetation cover of the ryams is secondary and arose under the influence of man. The degree of decomposition of the Fuscum deposit is always low, which, in addition to high humidity and low temperature, apparently contributes to its increased acidity, which inhibits microbiological processes. At the contact of the ryams and the borrowing proper, there is usually a belt of transitional fallow with a mesotrophic vegetation cover.

In addition to large borrow-ryam peat bogs, the South Baraba region is characterized by numerous small peat bogs in saucer-shaped depressions and depressions of suffusion origin along interfluves and ridges.

Transitional and lowland forest swamps usually form a narrow belt around ryams or are confined to mesorelief depressions. In the latter case, forest swamps are genetically related to birch groves. Kolochny bogs with a predominance of Carex intermedia are typical of the southern part of the region. Birch-reed bogs here are confined to flat, highly mineralized lowlands and represent one of the initial phases of bogging. The total area of the ryams is insignificant. They are found mainly in the northern half of the region.

According to the radiocarbon method absolute age The 3.1 m thick line is dated to the Middle Holocene, and the 1.35 m deep deposits are dated to the Late Holocene. The swamping processes are promoted by the gradual tectonic uplift of the area, which causes the disintegration of rivers and lakes into separate reservoirs.

East of the river Yenisei within the Asian part of the Union, seven large natural geographical areas are distinguished.

The West Siberian Plain is one of the largest flat territories world, it covers approximately 80% of Western Siberia.

Features of nature

In terms of total area, the West Siberian Plain is surpassed only by the Amazonian. The plain stretches from the coast of the Kara Sea south to the north of Kazakhstan. The total area of the West Siberian Plain is about 3 million square kilometers. km 2. Predominantly wide gently sloping and flat interfluves, which separate terraced valleys, prevail here.

The height amplitudes of the plain on average fluctuate between 20 and 200 m above sea level, but even highest points reach 250 m. Moraine hills in the north of the plain are combined with young alluvial and marine (river) plains, in the south - with lacustrine ones.

On the lands of the West Siberian Plain, a continental climate dominates, the level of precipitation here is different: in the tundra and steppe regions - about 200 mm per year, in the taiga area it increases to 700 mm. General average temperatures - - 16°C in winter, + 15°C in summer.

Large full-flowing rivers flow on the territory of the plain, in particular the Yenisei, Taz, Irtysh and Ob. There are also very large lakes (Ubinskoye, Chany), and many smaller ones, some of them are salty. Some regions of the West Siberian Plain are characterized by wetlands. The center of the northern part is continuous permafrost. Solonchaks and solonetzes are common in the extreme south of the plain. The western-northern territory in all respects corresponds to the temperate zone - forest-steppe, steppe, taiga, deciduous forests.

Flora of the West Siberian Plain

The flat relief significantly contributes to zoning in the distribution of vegetation cover. The zonality of this territory has significant differences in comparison with similar zones in Eastern Europe. Due to difficulties in runoff, lichens, mosses and shrubs grow predominantly in wetlands in the north of the plains. Southern landscapes are formed under the influence of groundwater with increased level salinity.

About 30% of the area of the plain is occupied by massifs of coniferous trees, many of which are swampy. Smaller areas are covered with dark coniferous taiga - spruces, firs and cedars. Occasionally, broad-leaved tree species are found in the southern regions. In the southern part there are very common birch forests, many of which are secondary.

Fauna of the West Siberian Plain

More than 450 species of vertebrates live in the expanses of the West Siberian Plain, of which 80 species belong to mammals. Many species are protected by law, as they belong to the category of rare and endangered. AT recent times, the fauna of the plain was significantly enriched with acclimatized species - muskrat, hare, teleutka squirrel, American mink.

In reservoirs live mainly carp and bream. In the eastern part of the West Siberian Plain there are some oriental views: chipmunk, Djungarian hamster, etc. In most cases, the fauna of this territory is not much different from the animal world of the Russian Plain.

Portal for the student. Self-training