The relief form of the West Siberian Plain briefly. I. Physiographic characteristics of the continent. Environmental problems and protected natural areas

Geological structure of Western Siberia

The base of the West Siberian Plain is a young plate of the same name. The plate in the east borders on the Siberian platform, from the south Paleozoic structures of Central Kazakhstan, Altai, and the Salair-Sayan region approach it, and in the west the border goes with the folded system of the Urals. Determining the northern border is difficult because it is covered by the waters of the Kara Sea. The base of the West Siberian plate is the Paleozoic basement, with an average depth of $7$ km. In the mountainous regions of the southeastern part, ancient Precambrian and Paleozoic rocks come to the surface, and within the West Siberian Plain they are hidden by a thick cover of sedimentary rocks.

The West Siberian plate began its formation in the Mesozoic era, in the Upper Jurassic period. At this time, the area between the Urals and the Siberian platform subsided, resulting in a huge sedimentation basin. Marine transgressions more than once captured the West Siberian Plate during its development. In the Lower Oligocene, the plate was freed from the sea and turned into a huge lake- alluvial plain. A new uplift of the northern part of the plate occurs in the late Oligocene and Neogene, and in the Quaternary period of the Cenozoic era the plate descends again. The development of the plate occurs in such a way that it resembles the process of oceanization and the development of swamps.

The slab foundation is divided into two parts:

1. External side belt. It is represented by slopes of a folded mountain frame, descending towards the central part of the depression. The foundation is located at a depth of $2.5$ km. In the southwest of the Kustanai saddle it approaches the surface at only $300$-$400$ m.
2. Inner area. It is divided into two stages: the southern stage – the Middle Ob meganteclise with a basement depth of up to $4$ km and the northern stage – the Yamalo-Taz megasyneclise descended to a depth of up to $12$ km.

Between the sedimentary cover and the foundation of the plate lies a transitional complex, the age of which is Triassic-Lower Jurassic. The foundation underwent extension and, as a result, the formation of an intracontinental rift zone with a system of graben-like depressions occurred. The depressions were the site of accumulation of sedimentary-volcanogenic and sedimentary coal-bearing continental strata up to $5$ km thick. The transitional complex also contains igneous rocks, represented by basaltic lavas and tuffs.

The development of the intracontinental rift zone within Western Siberia did not lead to the formation of a new ocean. Almost continuous formation of the cover under conditions of plate subsidence took place during the Mesozoic and Cenozoic era. It is composed of sandy-siltstone coastal-continental deposits and marine clayey and sandy-clayey strata. Their thickness reaches $4$ km in the southern part and $7$-$8$ km in the northern part. Numerous local structures are expressed in the sedimentary cover. These are mainly oil and gas reservoirs.

The general orographic features of Western Siberia were already formed by the end of the Neogene. The sea had a level lower than the modern one by $200$-$250$ m, and a significant part of the bottom of the Kara Sea was dry land. At the end of the Neogene, a general cooling of the climate and the development of Quaternary glaciation began.

Relief of Western Siberia

The development of the modern relief of Western Siberia was greatly influenced by the geological development of the territory, tectonic structure and exogenous relief-forming processes. The unevenness of the foundation was leveled out as a result of the accumulation of a thick layer of loose sediments. The periphery of the plain has a small amplitude of uplifts, reaching $100$-$150$ m. The central and northern parts of the plain are characterized by subsidence of $100$-$150$ m. However, a number of lowlands and hills can be distinguished. The plain is open to the north, towards the Kara Sea and has the shape of a stepped amphitheater.

There are three altitude levels on the territory of the West Siberian Plain:

1. Level one has a height of less than $100$ m and occupies half of the territory;
2. The second level is at an altitude of $100$-$150$ m;
3. The third level is located in the range of $150$-$200$ m with small areas from $250$-$300$ m.

The edges of the plain have more high level and are represented by the North Sosvinskaya, Verkhnetazovskaya, Lower Yisei uplands, Priobsky plateau, Turinskaya, Ishimskaya, Kulundinskaya, Ketsko-Tymskaya plains. The northern and central parts of the plain are represented by areas below $100$ m. These are the lowest areas of the plain. The Nizhneobskaya, Nadymskaya, Purskaya, Tazovskaya, Kondinskaya lowlands have a height of less than $50$ m. In the inner parts of the plain there is a strip of clearly defined hills - Verkhnetazovskaya, Numto ridge, Belogorsk continent, Lyulimvor.

From an orographic point of view, the elevation of the plain along the edges and the descent of the surface of the plate towards the center are clearly visible. The interior regions of the plain, where thick Mesozoic deposits occur, are already losing the clarity of expression in the relief of large basement structures. The number of inversion structures is growing. The Vasyugan Plain, for example, is nothing more than an anteclise located within a syneclise. Within the inner zone, under the conditions of recent subsidence, the formation of accumulative and stratified-accumulative plains took place. They are composed of Neogene-Quaternary loose sediments.

The types of morphosculptures created by exogenous relief-forming processes are located on the plain in the direction from north to south. Off the coast of the Kara Sea there are sea plains. They were formed in post-glacial times after the retreat of the sea. Moraine and fluvio-glacial plains are located to the south. Here they are adjacent to glacial, lacustrine-alluvial plains.

Minerals of Western Siberia

The main wealth of the West Siberian Plain is hydrocarbons - oil and gas. Experts estimate the area of ​​promising oil and gas fields at $1.7 million sq km. Associated with the middle Ob region are: large deposits such as Samotlorskoye, Megionskoye, located in the Nizhnevartovsk region. Large deposits in the Surgut region - Ust-Balykskoye, Fedorovskoye, etc.

Natural gas in the Subpolar region - the Medvezhye, Urengoy fields, in the Arctic - Yamburgskoye, Ivankovskoye, etc. There is oil and gas in the Urals, and new promising fields have been discovered on the Yamal Peninsula. In general, more than $300 oil and gas deposits have been discovered on the plain.

In addition to hydrocarbons, large deposits are known in Western Siberia coal, the main reserves of which are located within Kuzbass. Kuznetsk coal reserves are estimated at $600 billion tons. Almost $30$% of these coals are coking. The large thickness of coal seams and their close location to the surface allow their development not only by mines, but also open method. Brown Kansk-Achinsk coals lie to the northeast of the Kuznetsk basin. In the largest Itat field, the thickness of the layers reaches $80$ meters, and the depth ranges from $10$ to $220$ meters. The cheapest coal in Russia is mined here. Anthracite coals are concentrated in the Gorlovka basin, located in the south of the Novosibirsk region. Brown coals of the Tyumen region have not yet been put into operation.

Of the fuel resources in the depths of the West Siberian Plain there is $50$% of all-Russian reserves peat.

Stands out for its reserves and ore base. Significant iron ore resources are concentrated in the Narym, Kolpashevo, and Yuzhno-Kolpashevo deposits. Brown iron ores occur here. Gornaya Shoria is characterized by magnesium ore deposits - Tashtagol and Sheregesh. In Altai there are the Inskoye and Beloretskoye fields. There are deposits of manganese ores and nephelines in Kemerovo region. Place of Birth mercury in Altai.

The lakes of the Kulunda steppe contain reserves soda and salts.

Limestones in the Novosibirsk and Kemerovo regions.

Altai has significant reserves building materials.

In addition to minerals, Western Siberia is rich forest resources. Timber reserves account for $11$% of Russian reserves.

Note 1

Issues of protection and rational use of natural resources are also relevant for Western Siberia. Careless use of resources can ruin surrounding nature and lead to negative consequences.

West Siberian Lowland the third largest plain on our planet after the Amazon and Russian. Its area is about 2.6 million square kilometers. The length of the West Siberian Lowland from north to south (from the coast to the mountains of Southern Siberia and) is about 2.5 thousand kilometers, and from west to east (from to) - 1.9 thousand kilometers. The West Siberian Lowland is quite clearly limited in the north coastline sea, from the south - the hills of Kazakhstan and mountains, from the west - the eastern foothills of the Urals, and in the east - the valley of the Yenisei River.

The surface of the West Siberian Lowland is flat with a fairly insignificant difference in elevation. Small elevations are characteristic mainly of the western, southern and eastern outskirts. There their height can reach about 250-300 meters. The northern and central regions are characterized by lowlands with an altitude of 50-150 meters above sea level.

Along the entire surface of the plain there are flat areas of interfluves, as a result of which they are significantly swamped. In the northern part there are sometimes small hills and sandy ridges. Quite impressive areas on the territory of the West Siberian Lowland are occupied by ancient basins, the so-called woodlands. here they are mainly expressed by rather shallow hollows. Only some of the largest rivers flow in deep (up to 80 meters) valleys.

Yenisei River

The glacier also influenced the nature of the relief of Western Siberia. The northern part of the plain was mainly exposed to it. At the same time, water accumulated in the center of the lowland, as a result of which a fairly flat plain was formed. In the southern part there are slightly elevated sloping plains with many shallow basins.

More than 2,000 rivers flow through the West Siberian Lowland. Their total length is about 250 thousand kilometers. The largest are. Not only are they navigable, but they are also used to generate energy. They feed mainly from melt water and rain (in the summer-autumn period). There are also a large number of lakes here. In the southern regions they are filled with salt water. The West Siberian Lowland holds the world record for the number of swamps per unit area (the area of ​​the wetland is about 800 thousand square kilometers). The reasons for this phenomenon are the following factors: excess moisture, flat topography, and the ability of peat, which is available here in large quantities, to retain a significant amount of water.

Due to the large extent of the West Siberian Lowland from north to south and the uniformity of the relief, there are many natural zones within its borders. In all zones, lakes and swamps occupy fairly large areas. are absent here, and the area is rather insignificant.

The zone occupies a large area, which is explained by the northern position of the West Siberian Plain. To the south is the forest-tundra zone. As mentioned above, the forests in this area are mainly coniferous. The forest-swamp zone occupies about 60% of the territory of the West Siberian Lowland. Behind the strip coniferous forests followed by a narrow zone of small-leaved (mainly birch) forests. The forest-steppe zone is formed under flat-flat terrain. The groundwater lying here at shallow depths is the cause of a large number of swamps. In the extreme southern part of the West Siberian Lowland is located, which is mostly plowed.

The flat southern regions of Western Siberia are rich in ridges - sandy ridges 3-10 meters high (sometimes up to 30 meters), covered with pine forest, and kolki - birch and aspen groves that are scattered among the steppes.

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

Relief of the West Siberian Plain

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

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

Characteristic here various forms manifestations of permafrost and high swampiness. Also at the southern tip you can see both ancient and modern salt accumulations.

Rice. 1. Salt deposits.

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

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

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

On the peninsulas:

• Yamal;
• Tazovsky;
• Gydansky.

permafrost is observed.

Rice. 2. Yamal Peninsula.

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

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

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

• Barabinskaya;
• Vasyugan Plain;
• Kulundinskaya plain.

"Living" earth

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

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

Rice. 3. Underground river.

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

Table "Relief of the West Siberian Plain"

What have we learned?

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

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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 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 the latest movements 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 at different times opening up rivers in various 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 is not reflected in it European look Calluna vulgaris. 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 in the Arkhangelsk region and are rare in peat bogs in the 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 terraces above the floodplain 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 flooded with fresh deluvial melt water, and often with river hollow water; in the second half of the growing season, the fields dry out over a large peripheral area, and here favorable conditions arise for the capillary rise of saline soil-groundwater to the surface and efflorescence of salts (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 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 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).

Peat deposits in Western Siberia are extremely diverse in terms of the conditions of formation and development, qualitative and quantitative indicators of the deposit, vegetation cover, distribution patterns and other factors, the changes of which can be traced to a fairly clear pattern, closely related to natural latitudinal zoning. 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 bays and the Kara Sea there are coastal swamps that are flooded during surge winds sea ​​water. 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 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 its 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 layering.

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 peatlands 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 big amount various lichens.

Lowland peat deposits are located mainly on the first terraces above the floodplain 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 the spring, 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 Kondin 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 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 the hollows of ancient drainage, 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 region is composed of lacustrine-alluvial and deluvial deposits and is dissected by a highly developed hydrographic network into big number 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, more often in the upper part of the slope, among the upland deposits there are quite a few large lakes with sapropel deposits at the base.

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 peat bogs 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 peatlands 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, Vasyuganskoye, 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 hydrophilic sphagnum mosses (Sph . obtusum, Sph. majus, Sph. fallax, Sph. jensenii), forming a smooth carpet semi-submerged in water.

The thickness of the peat layer in floodplain peatlands 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 river waters, therefore 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 the 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. Dominate lowland marshes: 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 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, nutrition due to atmospheric precipitation, as well as partial elevation 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. In terms of high levels of decomposition and ash content, the deposit of bogs on watershed plains differs from the deposit of peat bogs on 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.

Rough terrain, poorly developed hydrographic network, waterproof horizon located close to the surface, slow runoff 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 heavy 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. In terms of chemical composition, the waters of the lakes, 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 a high 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 a 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 areas 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 a birch stand.

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 topography 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 the eastern half of the region, their areas here reach several thousand hectares, and the area of ​​ryams - high, rising up to 8-10 m above the level of the ryam - 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 bog stage; gradually, as the deposits grew, they came out of the influence of lake waters and continued to develop as atmospherically fed peat bogs. 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 fuscum deposits 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 the initial phases of swamping. 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.