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

Relief of the West Siberian Plain

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

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

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

Rice. 1. Salt deposits.

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

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

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

On the peninsulas:

• Yamal;
• Tazovsky;
• Gydansky.

permafrost is observed.

Rice. 2. Yamal Peninsula.

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

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

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

• Barabinskaya;
• Vasyugan Plain;
• Kulundinskaya plain.

"Living" earth

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

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

Rice. 3. Underground river.

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

Table "Relief of the West Siberian Plain"

Geographical area	Geological specificity	Relief
Yamal, Red Sea coast	Plate of the Paleozoic period. Covered with sedimentary cover formed by glacial deposits	Layers of horizontal order, turning into uplifts
Vasyuganye, Narym	Plate of the Paleozoic period. Covered with a sedimentary cover of river sediments and glacial deposits	Deflections in the central region and elevation in the form of Siberian Ridges
Altai foothills	Plate of the Paleozoic period. Covered with sedimentary cover	Plain elevation
	Caledonian orogeny	Destruction of ancient mountains. Formation of modern ones as a result of uplifting strata

What have we learned?

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

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The Russian Federation has one of the largest plains in area located on the surface of the globe. In the north, its border is the Kara Sea. In the south it extends to the space of the Kazakh fine sand. The eastern part is the Central Siberian Plateau. The border in the west becomes ancient. The total area of ​​this flat space is almost 3 million kilometers.

Relief features

The territory where the West Siberian Plain is located was formed a long time ago and has successfully survived all tectonic shocks.

It is strictly limited by officially recognized coordinates of the extreme points:

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

Hills

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

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

This is due to the location of the plain in the space of the Epihercynian plate, the basis of which is the foundation created by the overlay of Paleozoic sediments. This plate began to form in the Upper Jurassic period, the so-called Upper Jurassic.

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

Average values

This space is one of the largest low-lying areas on the planet, a type of accumulative plain, and has an average height of 200 meters. Low-lying areas are located in the central part of the area, in the northern areas, on the borders of the Kara Sea. Almost half space is located at an altitude below 100 meters above sea level. This ancient section of the earth’s space also has its own “elevations,” smoothed over billions of years since its creation. For example, the North Sosvinskaya Upland (290 meters). The Verkhnetazovskaya Upland rises to 285 meters.

Low places

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

It fully justifies the name “plain”. The height differences in the colossal space are minimal.

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

In absolute terms, this territory is also not distinguished by large numbers. The absolute height here is only 290 meters. Parameters were recorded on the North Sosvenskaya Upland. In most of the plain the figure is 100-150 meters.

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

Characteristic

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

Pay attention! The climate of the plain, due to its large area, ranges from moderately continental on the Russian Plain to sharply continental. Central Siberia is distinguished by this indicator.

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

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

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

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

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

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

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

Age indicator

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

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

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

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

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

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

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

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

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

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

The West Siberian Lowland is a single physical-geographical region consisting of two flat bowl-shaped depressions, between which lie latitudinally elongated elevations (up to 175-200 m), united orographically into the Siberian ridges.

The lowland is delineated by natural boundaries on almost all sides. In the west it is clearly 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 here passes into the adjacent hills of the Turgai plateau and the Kazakh hillocks.

The West Siberian Lowland occupies about 2.25 million km 2 and has a length from north to south of 2500 km, and from east to west (in the southern widest part) 1500 km. The exceptionally flat relief of this territory is explained by the leveling of the complex folded foundation of the West Siberian Platform with a thick cover of Meso-Cenozoic sediments. During the Holocene, the territory experienced repeated subsidence and was an area of ​​accumulation of loose alluvial, lacustrine, and in the north - glacial and marine sediments, the thickness of which in the northern and central regions reaches 200-250 m. However, in the south the thickness of Quaternary sediments drops to 5-10 m and the modern relief clearly shows signs of the impact of neotectonic movements.

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 reservoirs.

Large modern landforms of Western Siberia are morphostructures created by recent movements of the earth's crust. Positive morphostructures: hills, plateaus, ridges - have a more dissected topography and better drainage. Negative morphostructures are dominant for the relief of the territory - plains covered with a thickness of loose layered sediments, often gleyed to great depths. These properties impair the water permeability of the strata and inhibit groundwater flow.

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

Thus, the combination of physical and geographical factors that favorably influence the swamp formation process determined the intensity of the formation and accumulation of huge reserves of peat and the widespread distribution of peat deposits throughout 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 species characteristic of the taiga forests of Siberia, such as cedar, fir, and larch. Usually they, together with birch, spruce, and pine, make up the forest of swamps in various combinations and quantities. Almost pure stands of birch on peat bogs are quite common and, under appropriate conditions, are found in all peat-bog areas of the West Siberian Lowland. Pure thickets of willow are noted on the lowland peat bogs of the floodplains.

In the shrub layer of the vegetation cover of Western 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 herbaceous 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. Sph. rubellum and Sph. cuspi datum - typical inhabitants of high peat bogs in the northwestern region of the European part of the Union - are rarely found in the moss cover of peat bogs of the West Siberian Lowland. But in much greater quantities and in more southern latitudes, Sph are distributed here in the moss cover of swamps. lindbergii and Sph. congstroemii, which are typical for peat bogs of the Arkhangelsk region and are rare in peat bogs middle zone. Sometimes, in the ridge-lake areas of the Vasyugan watershed peatlands, Cladonia and Cetraria form continuous patches, 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 plant, which covers significant areas in the edge areas of the fields (in 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 by birch (up to 15-20 m in height) and conifers: spruce, cedar, pine, larch; in the undergrowth, along with willows (Salix sibirica, S. pentandra), black currant, rowan, bird cherry; in the shrub layer - bog myrtle, lingonberry, blueberry, cloudberry. The grass stand is rich in species and develops luxuriantly; it is dominated by C. caespitosa, other sedges include C. globularis, C. disperma, and taiga plants (Equisetum silvaticum, Casalia hastata, Pyrola rolundifolia) also grow in the forbs along with marsh plants. Elements of taiga flora are also observed in the moss cover: on hummocks Sph. warnstorfii - Pleuroziumschreberi and Hylocomium splendens, in inter-tussock depressions - Thuidium recognitum, Helodium blandowii, on the slopes of hummocks - Climacium dendroides. In the depressions between hummocks in Sogras one can often observe efflorescence of iron.

Most often, sogras cover the edge areas of low-lying marshy swamps of above-floodplain terraces along the channels of the Ob, Irtysh, Chulym, Keti, and Tym rivers. 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 between the Ishim and Tobol rivers in their middle reaches. Here they adjoin the lakes or surround them in a continuous ring. Huge areas are sometimes occupied by land in lowlands that are no longer connected with lakes, but bear the features of former channels between lakes.

Zaimishchno-ryam peatlands are often found in the eastern part of the South Barabinsk peat-bog region, where they are confined to lakes or flat depressions in which surface water stagnates for a long time. Among the fields there are scattered raised convex peat bogs, which occupy a small area compared to the fields. These are the well-known “ryams”. During the growing season, a variable water-mineral regime is created in the fields: in the spring and in the first half of summer they are filled with fresh deluvial soils. melt water, and often river hollows; in the second half of the growing season, the fields dry out over a larger peripheral area, and here favorable conditions arise for the capillary rise of saline soils to the surface. groundwater and salt efflorescence (Ca, Cl and SO 3) is usually observed on the surface.

The area of ​​the borrowing area can be divided into: a zone of constant moisture with relatively fresh waters (the central part of the borrowing area, the banks of lakes and river channels) and a zone of variable moisture, where both the degree of water content and the degree of mineralization of the feeding waters are variable (peripheral parts of the borrowings).

The central parts of the fields are covered with reed phytocenosis, in which the main background plants are reed, reed (Scolochloa festucacea), reed grass, sedge (C. caespitosa and C. wiluica). The phytocenosis includes Carex omskiana, C. buxbaumii, watchwort, and bedstraw (Galium uliginosum) as admixtures. 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 salinization of the substrate, a gradual thinning of reed thickets and the introduction of sedges (C. diandra, C. pseudocyperus), cattail and reed grass are observed. The sedge-reed phytocenosis is characterized by isolated scattered bushes of birch (B. pubescens) and willow (S. cinerea).

Along the periphery of the fields in the zone of variable moisture, reed grass (Scolochloa, festucacea), which in the conditions of Baraba is an indicator of mixed chloride-sulfate salinity, displaces reed grass from the plant cover, and here a grass-sedge phytocenosis arises mainly from reed grass, Carex omskiana, C. appropinquata and C. orthostachys with a small participation of the same reed grass.

The formation and development of ryams (oligotrophic pine-shrub-sphagnum islands) occurs in isolation from saline soils in both horizontal and vertical directions. Insulation in the horizontal direction is a deposit of loans; insulation in the vertical direction is a layer of reed peat with average degree decomposition 22-23%, underlying the upper ryam deposit. The thickness of the reed peat is 0.5-1.5 m, the thickness of the upper deposit is 0.5-1 m. The upper deposit is composed of weakly decomposed fuscum peat with a degree of decomposition of 5-20%. The stump content of the sphagnum deposit is low and falls from the upper layers to the lower ones.

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

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

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

The far 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 waterproof 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 several centimeters. Peatlands with deep deposits should be classified as relics of the Holocene climatic optimum. Polygonal and flat moss-sedge bogs are common here.

The wide distribution of eutrophic moss-sedge bogs with a flat surface (up to 20-25% of the total area) is noteworthy. Carex stans or Eriophorum angustifolium dominate here, with a moss carpet of Calliergon sarmentosum and Drepanocladus revolvens.

In river valleys among sedge bogs there are mounds covered with Sph. warnstorfii, Sph. lenense, Dicranum elongatum and lichens. Flowering plants include abundant thickets of Betula nana and Rubus chamaemorus.

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

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

Located further south area of ​​flat-hilly 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 mounds ranges from 30 to 50 cm, rarely reaching 70 cm. The area of ​​the mounds 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. Cetraria nivalis, C. cucullata, Cladonia amanrocraea are less common. The slopes of the hillocks are covered with green mosses. Aulacomnium turgidium, Polytrichum strictum, Dicranum elongatum are abundant. Among the flowering plants, the strongly oppressed Ledum palustre and Rubus chamaemorus grow in clusters. Between them are fragments of dicrane-lichen associations. The hollows are heavily watered with a continuous carpet of sphagnum mosses from Sph. lindbergii, Sph. balticum, Sph. subsecundum, Sph. Jensenii. Drepanocladus vernicosus is less common in hollows, Drepanocladus fluitans is common, Carex rotundata is common, Carex chordorrhiza is less common, Cephalozia fluitans sometimes grows. Along with swamps, wetlands are widespread, which are swampy shrub tundras with Betula papa and willows, sometimes with Ledum palustre, swampy moss tundras with Betula papa and Ledum palustre, hummocky tundras with Eriophorum vaginatum.

Area of ​​hummocky bogs occupies the northern part of the forest zone and the southern forest-tundra. The swampiness of the area is high. The mounds are found singly, but more often they are located in groups or ridges 1-2 km long, up to 200 m wide. Single mounds have a height of 2-2.5 m, soil mounds 3-5 m, ridge mounds reach a height of 8-10 m. Diameter the bases of the mounds are 30-80 m, the slopes are steep (10-20°). Inter-hill depressions are elongated, occupied by cotton grass-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, mainly Betula papa, is developed. Higher up the slope, lichens predominate. They are also typical for flat peaks, often subject to wind erosion.

The hummocky peatlands are topped with peat up to 0.6 m thick, under which lies a highly ice-saturated mineral core consisting of ice and loamy, silty-loamy, less often sandy loam material. The mineral core, in addition to ice-cement and individual crystals, contains numerous ice layers, the thickness of which reaches several tens of centimeters and usually increases downwards, the number of layers also decreases downwards.

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

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

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

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

Deposits of high peat bogs are shallow, on average about 2 m. poorly decomposed fuscum, complex, and hollow types of structure predominate.

Kondinskaya peat-bog region It is a vast alluvial and lacustrine-alluvial plain composed of layered sandy and clayey deposits. For the left bank of the river. Konda and the right bank of its lower reaches are characterized by the presence of rugged topography. The region is characterized by extremely high water content. A significant part of the Kondinsk region is confined to an area of ​​intense tectonic subsidence and is therefore characterized by the predominance of accumulation processes and the dominance of poorly drained swamps. Only the western part of the region, where denudation processes predominate, is characterized by low swampiness. The river beds are weakly incised. IN spring period The hollow waters of these rivers overflow widely and do not enter the banks for a long time. Therefore, river valleys are swamped over a large area; Near-terrace swamps are heavily flooded during high water. For the river basin Konda is characterized by the predominance of upland ridge-lake, ridge-lake-hollow and ridge-hollow peat deposits.

Lowland, sedge, reed, reed, birch-reed peat bogs are confined to river beds.

Transitional sedge-sphagnum, woody-sphagnum and sphagnum bogs are found on low terraces and in places where they join into bog systems. There are also complexes formed along the lines of surface intra-fallow flow of swamp waters.

The gradual tectonic subsidence of the surface affects the extremely high water content of the territory, which contributes to the intensive development of regressive phenomena in the swamps, the destruction of the sphagnum turf 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 peaty, but most have retained an open surface of water among peaty banks.

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

Transitional types of deposits make up peat bogs mainly on the second terrace of the river. Konda and its tributaries, and are also found along the edges of high-moor peat deposits, around mineral islands, or are confined to mesotrophic grass and moss swamps. The most common type of deposit is transitional swamp.

Low-lying deposits are found in river floodplains, forming narrow strips confined to overgrown rivers of high-moor swamps.

Analysis of spore-pollen diagrams dates the Kondinsky peatlands to the early Holocene. Peat bogs are of ancient Holocene age, the depth of which exceeds 6 m.

Middle Ob peat-bog region It is a lacustrine-alluvial and alluvial plain, composed on the surface mainly of cover deposits, underlying 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 drainable swamps found.

The region is characterized by the dominance of raised sphagnum bogs with ridge-lake-hollow and ridge-hollow complexes. The edges of swamps 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 first-order watersheds 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 peat bogs is represented by a fuscum deposit or a complex raised peat and bears lake-denudation or ridge-lake vegetation complexes on the surface, and ridge-hollow vegetation on the slopes.

On one-sidedly elevated watersheds with a gently concave asymmetrical surface, raised peat bogs give a drop in surface elevations 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 of structure with a ridge-lacustrine complex of vegetation on the surface. In the direction to the opposite slope of the watershed, the fallow becomes a complex upland with a ridge-hollow complex in the vegetation cover. The shallow-lying peripheral area with a transitional swamp deposit bears the vegetation of sphagnum swamps on the surface.

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

On second-order watersheds, 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, large peat deposits of the raised type with a predominance of fuscum deposits and with ridge-lake and ridge-hollow vegetation complexes on the surface are located on the watersheds of occurrence.

Basically, the Middle Ob region, as well as the Vasyugan region located to the south, are territories of almost continuous swamps. Swamps here completely cover watersheds of the first and second orders, terraces and river floodplains. 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. 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 the watersheds and fourth terraces. They are also found on low terraces and are confined to ancient drainage depressions, where accumulation processes dominate. The deposit is characterized by great homogeneity and is composed of complex raised, Scheuchzerian and fuscum peat.

The deposit of transitional swamps is represented by transitional swamps and forest-swamp 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-Tym peat-bog region occupies the area between the Keti and Tym rivers and extends east to the Yenisei. The watershed of the Ob and Yenisei has a clearly defined slope here with an increase in surface elevations to the east. The interfluve is composed of lacustrine-alluvial and deluvial deposits and is divided by a highly developed hydrographic network into a large number of small interfluves.

Due to the fact that the region is located within the contour of positive structures, the dominance of denudation processes determines the spread of well-drained swamps here. Regressive phenomena are less pronounced, there is a tendency for ridges to transgress, or ridges and hollows are in a state of dynamic equilibrium. The surface of the interfluve plateau has a clearly defined grivny 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 ridges, and in depressions - a transitional swamp or mixed swamp deposit with a lower horizon of low-lying sedge peat 1.5 m thick. Some ridges are ridges, towering above the peat deposit, filling the depressions between the ridges by 2-10 m. The width of the ridges is up to 5 km. They are composed of sandy sediments and are usually overgrown with taiga forest of pine, fir, cedar, and birch. The peatlands of the inter-ridge depressions are represented by transitional swamp and mixed swamp types of structure. On the upper part of the slope of the watershed towards the floodplain in the lower reaches of the Keti and Tym rivers there are often small round peat bogs of suffosion depressions (from 10 to 100 ha, rarely more) with transitional and upland deposits, less often with lowland deposits.

The slopes of the watersheds are eroded, weakly dissected or almost undivided by terrace ledges, cloak-like covered with peat deposits, 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 lowland deposits, higher up the slope - transitional, and in the upper sections of the slope - highland. On them, often in the upper part of the slope, rather large lakes with sapropel deposits at the base are scattered among the upper deposits.

In the upper reaches of the Keti and Tym rivers, the narrow terraces of both river valleys are covered with peat. Narrow peatlands stretched along rivers are often composed of transitional deposits. Raised, poorly 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 Ketyu and Tym rivers. The average thickness of raised bogs is 3-5 m, lowland 2-4 m. Raised bogs are composed of fuscum, complex and Scheuchzerian-sphagnum types of structure. The deposit of mesotrophic swamps is represented by transitional swamp and forest-swamp types of structure. The deposit of lowland bogs is composed of sedge peat.

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

A special feature of the Ket-Tym region is the significant distribution of transitional and lowland peatlands compared to other peat-bog areas of the forest zone, where exclusively raised bogs are dominant.

Tavdinskaya peat-bog region It is a flat, sometimes 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-Mansi Lowland, where accumulation processes predominate and the greatest swampiness occurs. Its northwestern edge extends into the Tavdo-Kondinskaya Upland, and its southern edge into the Tobol-Ishim Plain. The swampiness of the area is high. A significant area is occupied by poorly drained lowland peat deposits, the deposits of which are composed mainly of sedge and sedge-hypnum types of structure with a small participation of deposits of the forest-bog and forest subtypes. The thickness of the deposits is small (2-4 m), peat deposits 5 m deep are occasionally found. On flat watersheds, small high-moor peatlands with deposits 6-7 m thick are common, often folded almost to the mineral soil with fuscum peat of a low degree of decomposition. There are many lakes on the surface of peat deposits, which at one time served as centers for the formation of most 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 common; in the south, subaerial loess-like loams extend into its boundaries. The location of the area to the contours of positive structures determines the distribution of relatively drained swamps. Poorly drained swamps occupy the Demyan-Irtysh interfluve and depressions of the Ob-Irtysh watershed, where accumulation processes are developed.

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

Raised sphagnum bogs with ridge-hollow-lake and ridge-hollow complexes are confined to the flat tops of 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-grass 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 areas of watersheds. At the base of the peat bogs lie deoxidized silty calcareous loams, which enrich the deposit with a significant amount of mineral salts. The nature of the vegetation cover indicates that the hard-water regime currently exists. The peat 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. The edges of lowland deposits of the swamp subtype are represented by lowland forest (pine, birch) and forest swamp, wood-sedge, wood-sphagnum, swamp forest types of structure with deposit thickness from 1 to 2.8 m.

The upland areas in the form of islands lie among the lowland deposits. Their peat layer is represented predominantly by the fuscum type of structure and reaches a thickness of 6 m. The world's largest watershed heterogeneous peat deposit, Vasyuganskoe, with an area of ​​over 5 million hectares, is located in the region. Lowland peatlands generally do not form large areas in the region and, in addition to the slopes of watersheds, occupy mainly elongated areas in river valleys.

On low terraces, heavily swamped, lowland sedge-hypnum bogs predominate; lowland and transitional woody-sphagnum, woody-herbaceous bogs develop in the near-terrace part. Floodplains are swamped mainly in the upper reaches of rivers, where lowland sedge, sedge-willow, tree-sedge and forest swamps are formed. In their vegetation cover under the canopy of birch, Carex caespitosa and C. wiluica form high hummocks; in the inter-tussock depressions there is a large amount of forbs.

Deposits of the transitional type are located either at the contact of upland deposits with swampy 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 a vegetation cover of herbaceous plants(Carex lasiocarpa, C. rostrata, Scheuchzeria palustris) and from 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 peat bogs does not exceed 1.5-2 m. Their deposits of sedge, Scheuchzeria, wood-sedge or birch peat were in conditions of variable moisture with the participation of river waters, so its ash content is relatively increased.

The 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 are of ancient Holocene age.

Ket-Chulym peat-bog region characterized by less peat compared to Ket-Tymskaya, which is explained in the geomorphological features of the region. The watershed Ket-Chulym plateau has a significantly 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 peat bogs. The most widespread in the peat bogs of suffosion depressions is the transitional swamp deposit with a total thickness of the peat layer from 1 to 4.5 m. Rare deposits are less common in them, mainly fuscum, complex and Scheuchzerian-sphagnum with a depth of up to 3-6 m. Flat suffosion depressions 1-2 m deep are occupied by cotton grass-sphagnum or magellanicum deposits. Lowland deposits in suffosion depressions are rare and are represented by forest, tree-sedge, multi-layer forest-fen and sedge types of structure. They fill the deepest basins, in which the thickness of the peat suite reaches 4-5 m.

In the Ket-Chulym region, a certain pattern is noted in the distribution of near-terrace peat deposits. In the middle part of the river. Ulu-Yul peatlands are small in size and located on sharply defined terraces. Downstream of the river, the terrace ledges are smoothed out, the surfaces of the terraces expand, and the area of ​​peat deposits increases. The latter acquire an elongated shape and are stretched parallel to the river. Near the mouth of the river. The Ulu-Yul terraces are even less pronounced and peat deposits merge with each other, covering the surface of several terraces.

On terraces and in near-terrace parts of river valleys, peat bogs are smaller in area (in comparison with the peat bogs of the Ket-Tym region) and, without merging into large-scale massifs, on the terraces they form chains of isolated deep-lying peat deposits extended parallel to the river, often of lowland type with forest, wood-sedge or sedge deposit.

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

In general, this is an area of ​​high swampiness of weakly dissected gently flat wide river valleys with large lowland sedge-hypnum bogs at the bottoms of terraces and along their slopes and with medium-sized raised and transitional peat bogs on watersheds. The total swampiness of the region is up to 40%.

An example of a peat deposit of the first terraces above the floodplain 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 main bank. Its deposit is almost entirely composed of sedge-hypnum and sedge peats, confirming the existence of ground 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 forest-steppe conditions during the formation of the lakes. In the lower horizons of the deposit or on the edges of the deposit, high ash content of peats is observed as a result of clogging of the deposit with colluvial drifts.

North Baraba peat-bog region watershed sedge-hypnum bogs in the north borders on the Vasyugan peat-bog region, in the south on the South Barabinskaya region and is a gently undulating, weakly dissected plain. The region is composed of loess-like loams. There is little peat. It is dominated by small low-lying peatlands, such as borrowed areas, with an area of ​​10 to 100 hectares. 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 peat area is lowland peat (54%) and approximately 27% is upland; The percentage of transitional peatlands here is relatively large (19%).

In the central part of the region there are many lakes, depressions and peat deposits. In the western part of the region, on the slopes of the Tara-Tartas interfluve, the main area of ​​sedge-hypnum bogs is concentrated. Hypnosis swamps develop in low-lying elements of the relief, mainly in places where hard-water groundwater flows emerge, along the slopes of watersheds or in the near-terrace parts of river valleys. Therefore, a slightly increased ash content (up to 8-12%) is characteristic of hypnotic peats and peat deposits. The ash content of some near-terrace hypnotic peat bogs averages 6-7%. The same percentages are used to measure the ash content of the sedge-hypnum peat bogs of the Tara-Tartas interfluve.

Towards the east, sedge-hypnum peat bogs give way to their leading position in the lowland type to forest-bog and forest deposits. The latter are located here along the edges of peat deposits, in the central areas of which, as well as in areas with a more elevated bottom topography, there are islands of upland deposits. Moreover, the fuscum fallow is usually peripheral in relation to the complex upland one, 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, recharge from atmospheric precipitation, as well as partial uplift of the territory create favorable conditions for the gradual transition of lowland swamps to the oligotrophic stage of development. In the river valleys directly adjacent to the river ridges, the richest in floristic composition are the woody and herbaceous swamps (sogr). In that part of the valley where anoxic groundwater flows and colluvial water does not penetrate, sedge-hypnum bogs are formed. In addition to typical mosses, there are sedge and sedge-grass bogs, and in the east there are reed bogs, characteristic of the grass bog zone.

In the riverine parts of watersheds, along the banks of the upper reaches of rivers, and in the depressions of 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. Presence of ryams (high sphagnum islands) characteristic feature sedge-hypnum bogs of the North Barabinsk region. Hypnosis deposits are more typical for swamps on low terraces, where soluble calcium salts predominate in the water-mineral nutrition. Deposit of swamps of watershed plains along high rates the degree of decomposition and ash content differs from the peat deposits of low terraces, which have a more complex stratigraphy. Here you can find grass-hypnum, cotton grass-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 play a significant role in the structure of deposits of lowland near-terrace and floodplain-near-terrace bogs. Transitional forest swamps are widespread. They form in the interfluves, in the terraces above the floodplain and in the near-terrace parts. The deposits of these swamps are represented by transitional forest and forest-swamp types of structure.

In the ryams, 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 types of peat. The bottom layers of the deposit are usually represented by peat of transitional and lowland types. The average depth of peat deposits on 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 formation process dates back to the early Holocene.

Tobol-Ishim peat-bog region 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 lowland swamps such as borrows with an area of ​​10 to 100 hectares. The location of the positive contours of the structures determines the development of predominantly well-drained peat deposits here.

The ridged nature of the relief, a poorly developed hydrographic network, a waterproof horizon located close to the surface, and slow runoff of surface waters led to the formation in the interridge spaces of a huge number of lakes, usually round or oval with shallow depths, a flat bottom and strong overgrowth. Lakes are often adjacent to or surrounded by small, shallow-lying sedge-reed bogs. During the period of snowmelt, the fields are filled with meltwater, turning into temporary shallow reservoirs, often interconnected, and then the flow through such a chain of lakes connected by the fields has the character of a river. There are very few isolated lakes. By chemical composition The waters of the lake, sometimes located in close proximity to one another, are distinguished by significant diversity. Salty, bitter and fresh lakes lie almost nearby.

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

Smaller areas of borrowings are common in the southern part of the region around salt lakes. They are very shallow, composed of reed peat with an increased degree of decomposition and high ash content. The reed association, and less often the sedge association, predominate in their vegetation cover.

In the sandy spaces of the Tobol region and in the northern part of the region on the right bank of Ishim, lowland peat bogs (sedge and sedge-hypnum) have separate areas (such as ryams) with high-lying deposits composed of fuscum peat of low degree of decomposition, with a convex surface and secondary vegetation cover of pine trees. shrub phytocenosis that developed as a result of repeated fires.

In small basins of suffoses of ionic origin, shallow “split” peatlands of lowland type are found. They developed in solonetz microrelief depressions - “saucers”. Salinization and the subsequent process of swamping lead to the appearance of swampy meadows with Carex intermedia, which are exclusively characteristic of this territory, which are subsequently covered with thickets of shrubs, mainly Salix sibirica, and birch stands.

There are also treeless “spike” swamps with sedge hummocks on the surface, surrounded on the periphery by tall-trunked birch. They formed in deeper and more moist depressions with diverse wetland vegetation, greatly varying in composition in some cases: with hummocks of Carex omskiana, sometimes with Salix sibirica in the shrub layer. Such peat bogs are never covered over the entire area with birch; the deposits in them are tree-sedge.

South Baraba peat-bog region large borrow-ryam peatlands 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.

Soil salinization processes (including peat soils) are widespread 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 the southwestern direction in combination with interridge depressions. 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 the depressions between the ridges are completely swamped. Characteristic of the Baraba relief are suffusion depressions on various surface elements and a large number of lakes, different in size, origin and chemical composition of water.

The area's swampiness is approximately 33%. Lowland reed-sedge peatlands predominate here, constituting up to 85% of the total wetland area. The remaining 15% is distributed between the upper ryam deposits and the transition deposits of their peripheral areas.

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

The emergence of high-lying ryam deposits among lowland deposits is associated with the feeding of ryam areas with fresh and slightly saline lake 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 deposit in the form of a thin layer of sapropel.

The degree of decomposition of borrowed peats, as a rule, exceeds the species indicator (30-50%), the average ash content is 20%. The deposit of borrowings is composed of highly mineralized peats of the swamp group: reed, reed-sedge and grass (with a predominance of remains of light grass and reed grass in the fiber). The total thickness of the borrowing deposits reaches 1.5 m. In the vegetation cover, in the direction from the center to the periphery, reed, sedge-reed and sedge (or grass-sedge) phytocenoses are successively replaced. The latter borders on saline meadow vegetation. Areas fed by lake waters did not experience variability in moisture and salt conditions. Protected from the influence of saline groundwater by the surrounding low-lying deposits, they were overgrown with alloys of Sph. teres, the reservoirs passed into the peat stage; gradually, as the deposits grew, they came out from under the influence of lake waters and continued to develop as atmospherically fed peatlands. Dominance in these areas of Sph. fuscum maintains a regime of high humidity and low temperature in the deposit. Sph. fuscum created its own substrate and microclimate even in forest-steppe conditions and over thousands of years deposited powerful deposits of high-moor peat.

The modern vegetation cover of the ryams is secondary and arose under human influence. The degree of decomposition of the fuscum deposit is always reduced, which is facilitated, in addition to increased humidity and low temperature, apparently by its increased acidity, which inhibits microbiological processes. At the contact of the ryams and the dams themselves, there is usually a belt of transitional deposits with mesotrophic plant cover.

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

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

According to the radiocarbon method, the absolute age of the ryam with a thickness of 3.1 m dates back to the Middle Holocene, and the borrows with a depth of 1.35 m - to the Late Holocene. The processes of swamping are facilitated by the gradual tectonic uplift of the area, which causes the disintegration of rivers and lakes into separate bodies of water.

East of the river The Yenisei within the Asian part of the Union is divided into seven large natural geographical areas.

West Siberian Plain with a total area of ​​3.5 million square meters. km belongs to the accumulative type of plains. It is one of the largest low-lying swampy areas on earth, covered with tundra and taiga. For a long time the harsh climate and frozen ground prevented geological exploration of the territory. Today, geologists attribute the plain to the presence of the tectonic plate of the same name. Its foundation is best studied along the periphery. By drilling deep and ultra-deep wells Its southern region and center have been quite well studied by geologists. If drilling is not available, scientists use geophysical data. The tectonic structure and structure of the large West Siberian plate is very diverse and not entirely clear. It is the structure of the foundation that generates lively scientific discussion. Most scientists agree that the crystalline basement consists of large geoblocks, consolidated and separated by deep faults.

Geology of the West Siberian Plain

The plain of Western Siberia is located on the epihercynian tectonic plate of the same name, which has a clearly defined two-tier structure. At its base, it is represented by a heterogeneous foundation of different ages from the Precambrian to the Paleozoic. The base of the tectonic plate is primarily a depression with steep sides to the northeast. It is exposed in a few elevated areas along the edges of the lowlands. The basement rocks are covered with a layer of marine and continental Mesozoic and Cenozoic geological deposits of clays and sandstones up to 1000 meters thick. In depressions at the base of the plate, the thickness of sediments reaches up to 3-4 thousand meters. In the basement of the plate, geologists distinguish three ophiolitic volcanic belts. They were named Nizhnevartovsk-Aleksandrovsk, Trans-Ural and Western Surgut based on their location; schist deposits, siliceous shales and jaspers of Devonian age appear here.

Scientists determine the age of the foundation in pre-Paleozoic times, the ancient Baikal, the subsequent Caledonian and Hercynian folds. It is dissected by deep tectonic faults of different geological ages. The Omsk-Pursky and Trans-Ural fault lines extend submeridionally. Schemes of the location of isolated tectonic structures on the plain show that in the foundation of the plate one can distinguish between the edge and extensive internal areas; it has depressions and uplifts. It is covered by a cover of sedimentary rocks of Mesozoic and Cenozoic age. The cover includes marine and coastal-continental deposits up to 3-4 thousand meters in the south and 7-8 thousand meters in the north. In the south, young alluvial and lacustrine sedimentary strata formed; to the north, marine and glacial sediments formed.

History of the formation of the territory

The formation of the plate began in the Late Jurassic period. Then, as a result of the action of the geological forces of the earth, the huge area between the Urals and the Siberian platform gradually began to descend. During its development, the plate was repeatedly exposed to marine transgressions. During the Oligocene period, the ancient sea left the West Siberian plate, and a huge lacustrine alluvial alluvial plain was formed here. In the Oligocene and later in the Neogene, its individual parts experienced tectonic uplift and subsidence under the influence of the internal forces of the earth. During its development, the territory was repeatedly flooded by the sea in the Jurassic, Cretaceous and Paleogene periods. This is the reason for the constant swampiness of the plain over vast areas.

In the Upper Triassic, the plate subsided differentially and gradually accumulated sedimentary cover. In Mesozoic and Cenozoic geological times, these processes continued with prolonged subsidence of the plate. Today the cover is composed of sandy, siltstone, mudstone, continental and clayey deposits up to 8 km in the north of the plain. When tectonic movements occur on different stages development, local geological structures arose in the cover. In such uplifts on the territory of near-fault zones, reservoirs of gas and oil were formed.

In the Oligocene, tectonic movements separated the sea of ​​Western Siberia from the large Arctic basin. For a short time, the marine regime remained in the center of the plate, but in the Oligocene the sea left the plain. Therefore, the upper horizon of the cover is composed of continental lacustrine-alluvial and sandy-clay deposits up to 2 km thick.

In the Neogene period, the Ob-Yenisei sublatitudinal uplifts gradually began to separate; they are located above the large Trans-Siberian Fault and clearly correspond to the Siberian Uvaly hills. It was then, in the Neogene period, that the main features of the orographic pattern of the plain gradually formed. Depressions in the relief corresponded to troughs; large rivers flowed through them. The ancient sea was 200 meters below the modern level, the bottom of the Kara Sea was dry land.

Tectonic structures

In the most submerged northern region of the plate there are the Yamalo-Gydan and Nadym-Taz syneclises. They are separated by the narrow sublatitudinal Messoyakha megaswell. In the center of the slab there is a large Khantei anteclise. In it, geologists distinguish two formed vaults, they were called Surgut and Nizhnevartovsk. Large anteclises are Ket-Vakh and Khantei. To the south of them are the sublatitudinal Kulunda and Middle Irtysh syneclises. The Khantymansi and Chulym syneclises stand out in size. The Pursky Trench is located above the Koltogorsk-Urengoy rift zone. The Khudosei tectonic trench connects with the small Chulman syneclise.

Between the cover and the pre-Paleozoic foundation there is a transitional layer of rocks of Triassic and Jurassic geological age. Geologists associate its formation with movements of the foundation, which resulted in the formation of a rift zone inside the continent with graben-like depressions. Sedimentary and volcanogenic coal-bearing horizons accumulated in them; their thickness reaches up to 5 km. The volcanic strata of the transitional geological layer are basaltic lavas. The formation of the rift zone on the continent in Western Siberia did not continue, and a new ocean did not form.

The connection between tectonics and minerals

In the deposits of the sedimentary cover of the plain, horizons of pure fresh, mineralized underground water and brine are concentrated. Some areas have hot springs with temperatures ranging from 100°C to 150°C. In the depths of the plate there are industrially rich deposits of natural gas and oil. They are concentrated in the depths of the West Siberian oil and gas basin, which is promising for production. At a depth of more than two kilometers in the sediments of the Khanty-Mansi large syneclise, in the Salym, Surgut and Krasnoselsky regions, the richest shale oil deposits in the country are concentrated in layers that belonged to the Bazhenov formation.

Relationship between tectonic structure and relief

Modern forms of relief of the plain are often due to the long-term geological development of the territory, its tectonic structure and the influence of physical weathering processes. The modern orographic pattern depends on the tectonic structure and plate structure. This gradually occurs even under conditions of long-term Meso-Cenozoic subsidence and the process of accumulation of thick layers of loose sediments. Such accumulation levels out all the irregularities of the Epi-Hercynian basement, which is in relative late Cenozoic peace. The small amplitude of new tectonic movements determines the low-lying hypsometric status of the plain. The maximum amplitudes of uplifts on the plain are heights from 100 to 150 m on the periphery; identical subsidences are observed to the north and closer to the center. On the vast territory of the plain, lowland and elevated areas can be distinguished.

The entire territory of the Western Siberian plain plunges stepwise from south to north and looks like a stepped giant amphitheater in the orographic picture; it is open to the coast of the Kara Sea. In its orographic structure, geomorphologists distinguish three altitude levels. Half of the territory belongs to the first level with a height of up to 100 meters. The second hypsometric level is heights from 100 m to 150 m, the third from 150 m to 200 m, some areas up to 250-300 m.

The relief of Western Siberia is monotonous, almost flat, with a predominant height of 100 meters. Only on the periphery, in the west, north and south, the height of orographic structures reaches 300 meters. In the center of the plain there are large Sredneobsky and Kondinsky lowland areas. In the north lie the vast Nadym, Lower Ob and Pur lowlands. Along the periphery of the plain there are low Turin, Ishim, North Sosvinsk plains, the Chulym-Yenisei and Priobskoe plateaus, the Lower Yenisei, Verkhnetazovsk and Tym uplands. The 150-meter individual ridges of the Siberian Uvals run in a single chain inside the plain. Parallel to them is the vast Vasyugan Plain.

A clear correspondence is observed between the Lyulimvor and Verkhnetazovskaya heights with anticlinal tectonic structures. Syneclises in the foundation of the slab correspond to the Kondinskaya and Barabinskaya lowlands. Disconformity or inversion structures are often found on the plain. Thus, the Vasyugan Plain was formed on a gently sloping syneclise, and the Chulym-Yenisei Plateau is located on a tectonic trough of the plate foundation.