The 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 lowland swampy areas on earth, covered with tundra and taiga. For a long time, the harsh climate and permafrost hindered the geological study of the territory. Today, geologists attribute the plain to the presence of the tectonic plate of the same name. Its foundation is best studied in the periphery. By the method of drilling deep and superdeep 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 precisely the structure of the foundation that causes a 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 pronounced two-tier structure. At its base, it is represented by a heterogeneous basement of different ages from the Precambrian to the Paleozoic. The base of the tectonic plate is primarily a depression with steep sides from the northeast. It is exposed in a few elevated areas along the edges of the lowland. 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 slab, the thickness of the deposits reaches up to 3-4 thousand meters. In the basement of the slab, geologists distinguish three ophiolite volcanic belts. They were named according to their location Nizhnevartovsk-Aleksandrovsk, Trans-Ural and West Surgut, scoop-shale deposits, siliceous schists and jaspers of Devonian age appear here.
Scientists determine the age of the foundation by the pre-Paleozoic time, the ancient Baikal, followed by the Caledonian and Hercynian folding. It is dissected by deep tectonic faults of different geological age. The fault lines of the Omsk-Pursky and Zauralsky ones extend submeridionally. The diagrams of the location of isolated tectonic structures on the plain show that in the basement of the slab one can distinguish between the marginal and the vast inner regions, it has depressions and uplifts. It is covered by a cover of sedimentary rocks of the Mesozoic and Cenozoic age. In the cover, marine and coastal-continental deposits are distinguished up to 3-4 thousand meters in the south and 7-8 thousand meters in the north. In the south, young alluvial and lacustrine strata of sediments were formed, to the north, marine and glacial ones.
The history of the formation of the territory
The formation of the plate began in the Late Jurassic. Then, as a result of the action of the geological forces of the earth, a huge area between the Urals and Siberian platform gradually began to decline. The plate repeatedly experienced the impact of marine transgressions during its development. In 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, some of its parts experienced tectonic uplifts and subsidences under the influence of the internal forces of the earth. During development, the territory was repeatedly flooded by the sea in the Jurassic, Cretaceous and Paleogene periods. This is the reason for the constant swamping of the plain over vast expanses.
In the Upper Triassic, the plate subsided differentially and gradually accumulated a sedimentary cover. In the Mesozoic and Cenozoic geological time these processes continued with prolonged deflection of the slab. Today, the cover is composed of sandy, silty, mudstone, continental, and clay deposits up to 8 km in the north of the plain. With the occurrence of tectonic movements at different stages of development, local geological structures arose in the cover. In such uplifts on the territory of the fault zones, reservoirs of gas and oil were formed.
In the Oligocene, tectonic shifts separated the sea of Western Siberia from the large Arctic basin. The maritime regime was still preserved in the center of the plate for a short time, but in the Oligocene the sea left the plain. Therefore, the upper horizon of the cover is composed of continental lacustrine-alluvial and sandy-argillaceous deposits up to 2 km thick.
IN Neogene period the Ob-Yenisei sublatitudinal uplifts began to gradually separate, they are located above the large Trans-Siberian fault and clearly correspond to the Siberian Uvaly upland. It was then in the Neogene period that the main features of the plain orography pattern gradually formed. The depressions in the relief corresponded to the troughs; major rivers. The ancient sea was 200 meters below the modern level, the bottom of the Kara Sea was land.
Tectonic structures
The Yamal-Gydan and Nadym-Taz syneclises are located in the most submerged northern region of the plate. They are separated by a narrow sublatitudinal Messoyakha megaswell. In the center of the plate is a large Khantei anteclise. In it, geologists distinguish two arches that have taken shape, they are 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 Khanty-Mansiysk and Chulym syneclises stand out in size. Above the Koltogorsk-Urengoy rift zone is the Pursky trench. The Khudosei tectonic trench connects with the small Chulman syneclise.
Between the cover and the pre-Paleozoic basement there is a transitional layer of rocks of the Triassic and Jurassic geological age. Geologists associate its formation with basement movements, as a result of which a rift zone was formed 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, a new ocean did not form.
The connection of tectonics with minerals
In the deposits of the sedimentary cover of the plain, horizons of pure fresh, mineralized underground water and brine are concentrated. In some areas there are hot springs with temperatures ranging from 100°C to 150°C. In the bowels of the plate there are industrially richest deposits of natural gas and oil. They are concentrated in the bowels of the West Siberian oil and gas basin, which is promising for production. At a depth of more than two kilometers in the deposits of the Khanty-Mansiysk large syneclise, in the Salym, Surgut and Krasnoselsk regions, in the layers belonging to the Bazhenov formation, the richest shale oil deposits in the country are concentrated.
The connection of the tectonic structure with the relief
Modern landforms 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 structure of the plate. This gradually occurs even under conditions of prolonged Meso-Cenozoic subsidence and the process of accumulation of thick strata of unconsolidated deposits. Such accumulation levels out all the irregularities of the Epihercynian basement, which is in a relatively late Cenozoic calm. A small amplitude of new tectonic movements determines the low hypsometric status of the plain. The maximum amplitudes of uplifts on the plain are from 100 to 150 m at the periphery; to the north and closer to the center, identical subsidences are observed. On the vast territory of the plain, low-lying and elevated areas can be distinguished.
The entire territory of the plain of Western Siberia gradually plunges from south to north and looks like a stepped giant amphitheater in the orographic pattern; it is open to the coast of the Kara Sea. Geomorphologists distinguish three altitudinal levels in its orographic structure. Half of the territory belongs to the first level up to 100 meters high. The second hypsometric level is 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 predominance of 100 meters in height. 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 low-lying areas. In the north are the vast Nadym, Nizhneobsk and Pursk lowlands. Along the periphery of the plain are the low Turin, Ishim, North Sosvinskaya plains, the Chulym-Yenisei and Priobskoye plateaus, the Lower Yenisei, Upper Taz and Tymskaya uplands. 150-meter separate ridges of the Siberian Ridges pass in a single chain inside the plain. Parallel to them is the vast Vasyugan Plain.
A clear correspondence is observed between the Lulimvor and Verkhnetazovskoye uplands and anticlinal tectonic structures. The syneclises in the basement of the slab correspond to the Kondinsky and Baraba lowlands. Unconformity 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 basement.
Western Siberia is a territory stretching for 2500 km from the Arctic Ocean to the dry steppes of Kazakhstan and for 1500 km from the Ural Mountains to the Yenisei. About 80% of the area of Western Siberia is located within the West Siberian Plain, which consists of two flat bowl-shaped heavily swamped depressions separated by Siberian Ridges elevated to 175-200 m. In the southeast, the West Siberian Plain, gradually rising, is replaced by the foothills of Altai, Salair, Kuznetsk Alatau and Mountain Shoria. The total area of Western Siberia is 2.4 million km2.
Geology and orography
At the base of the West Siberian Plain lies the West Siberian Plate. In the east, it borders on the Siberian platform, in the south - on the Paleozoic structures of Central Kazakhstan, Altai and the Salair-Sayan region, in the west - on the folded system of the Urals. northern border plate is unclear, it is covered by the waters of the Kara Sea.At the base of the West Siberian Plate there is a Paleozoic basement, the depth of which is, on average, 7 km. The most ancient Precambrian and Paleozoic rocks in Western Siberia come to the surface only in the mountainous regions of its southeast, while in the West Siberian Plain they are hidden under a thick cover of sedimentary rocks. The West Siberian Plain is a young subducting platform, the speed and magnitude of subsidence of individual sections of which, and hence the thickness of the cover of loose deposits, are very different.
The formation of the West Siberian Plate began in the Upper Jurassic, when, as a result of breaking, destruction and regeneration, the vast territory between the Urals and the Siberian platform sank, and a huge sedimentary basin arose. In the course of its development, the West Siberian Plate was captured more than once by marine transgressions. At the end of the Lower Oligocene, the sea left the West Siberian plate, and it turned into a huge lacustrine-alluvial plain. In the middle and late Oligocene and Neogene, the northern part of the plate experienced uplift, which was replaced by subsidence in the Quaternary. The general course of the development of the plate with the subsidence of colossal spaces resembles the process of oceanization that has not reached its end. This feature of the plate is emphasized by the phenomenal development of waterlogging.
Much remains unclear and controversial regarding the nature, size, and number of ancient glaciations in this area. It is believed that glaciers occupied the entire northern part of the plain north of 60 o N. latitude. Due to the continentality of the climate and the low amount of precipitation, the glaciers on the West Siberian Plain were thin, inactive, and did not leave behind powerful moraine accumulations.
Climate
Western Siberia is located almost at the same distance from Atlantic Ocean, and from the center of continentality of Eurasia, so its climate is moderately continental. In winter and summer, when cyclonic activity, and with it the influx of Atlantic air, weakens, Arctic air enters Western Siberia. The deep penetration of Arctic air masses is facilitated by the flatness of the terrain and its openness to the north.The average temperature in January decreases from -15 (C in the southwest to -30 (C) in the northeast of Western Siberia. The average temperature in July increases from +5 (C in the north to +20 (C) in the south. The northeast is the most continental Western Siberia, where the difference between the average temperatures in January and July reaches 45 o.
Hydrography
The rivers of Western Siberia belong to the Kara Sea basin. The largest water artery - the Ob with a tributary of the Irtysh - is one of the greatest rivers in the world. The Ob River is formed at the confluence of the Biya and Katun, originating in Altai, and flows into the Ob Bay of the Kara Sea. Among the rivers of Russia, it ranks first in terms of basin area and third in terms of water content. In the forest zone, up to the mouth of the Irtysh, the Ob receives its main tributaries: on the right - the rivers Tom, Chulym, Ket, Tym, Vakh; on the left - the Parabel, Vasyugan, Bolshoi Yugan and Irtysh rivers. The largest rivers in the north of Western Siberia - Nadym, Pur and Taz - originate in the Siberian Uvals.Geographic zoning
Western Siberia covers five natural zones: tundra, forest-tundra, forest, forest-steppe, steppe, as well as low-mountain and mountain regions of Salair, Altai, Kuznetsk Alatau and Mountain Shoria. Perhaps nowhere on the globe does the zonality of natural phenomena manifest itself with the same regularity as on the West Siberian Plain.Tundra occupying the northernmost part Tyumen region(Peninsula Yamal and Gydan) and having an area of about 160 thousand km2, has no forests. Lichen and moss tundras of Western Siberia are found in combination with hypnum-grass and lichen-sphagnum tundras, as well as large-hilly swampy massifs.
Forest-tundra zone extends to the south of the tundra in a strip of about 100-150 km. As a transitional zone between tundra and taiga, it is a mosaic combination of areas of light forests, swamps, and thickets of shrubs. The northern limit of woody vegetation is represented by sparse crooked larch forests, occupying areas along river valleys.
Forest (taiga, forest-bog) zone covers the space between 66 o and 56 o N.S. a strip of about 1000 km. It includes the northern and middle parts of the Tyumen region, the Tomsk region, the northern part of the Omsk and Novosibirsk regions, occupying about 62% of the territory of Western Siberia. The forest zone of the West Siberian Plain is divided into subzones of the northern, middle, southern taiga and birch-aspen forests. The main type of forests in the zone are dark coniferous forests with a predominance of Siberian spruce, Siberian fir and Siberian pine (cedar). Dark coniferous forests are almost always found in ribbons along river valleys, where they find the conditions for the drainage they need. On the watersheds, they are confined only to hilly, elevated places, and flat territories are occupied mainly by swamps. The most important element of the taiga landscapes is lowland, transitional and upland swamps. The forest cover of Western Siberia is only 30.5% and is a consequence of weak dissection and the associated poor drainage of the entire region, which contributes to the development of not forest-forming, but swamp-forming processes throughout the entire area of the taiga zone. The West Siberian Plain is characterized by exceptional watering and swampiness, its middle and northern parts are among the most waterlogged spaces on the earth's surface. The world's largest swamps (Vasyugan) are located in the southern taiga. Along with the dark coniferous taiga, pine forests occur on the West Siberian Plain, confined to the sandy deposits of the ancient alluvial plains and to the sandy terraces along the river valleys. In addition, within the forest zone, pine is a characteristic tree of sphagnum bogs and forms peculiar associations of sphagnum pine forests on waterlogged soils.
forest-steppe zone , adjacent to the subzone of deciduous forests of the forest zone, is characterized by the presence of both forest and steppe plant communities, as well as swamps (ryams), solonchaks and meadows. The woody vegetation of the forest-steppe zone is represented by birch and aspen-birch forests, which occur in islands or in the form of pegs, usually confined to saucer-shaped depressions, while the main background is formed by meadow and forb-cereal steppe. Only in the Tobol and Ob region of this zone are natural insular pine forests common. characteristic feature The forest-steppe of Western Siberia is a hryvnia-hollow relief and an abundance of saline endorheic lakes.
steppe zone covers the southern part of the Omsk and the southwestern part of the Novosibirsk regions, as well as the western part Altai Territory. It includes the Kulundinskaya, Aleiskaya and Biyskaya steppes. Ribbon pine forests grow along the ancient glacier water runoffs within the zone.
The significant height of the mountains of Western Siberia determines the development of altitudinal zonation here. In the vegetation cover of the mountains of Western Siberia, the leading position is occupied by forests covering most of the area of the Salair Ridge and the Kuznetsk Alatau and about 50% of the territory of Altai. The alpine belt is clearly developed only in the Altai mountains. The forests of Salair, Kuznetsk Alatau, the northeastern and western parts of Altai are characterized by the wide development of the relict formation of the black taiga, which is found only in the mountains of southern Siberia. Among the black taiga in the basin of the Kondoma River there is a relic "linden island" - a plot of linden forest with an area of about 150 km2, considered as a remnant of tertiary vegetation.
Biodiversity
Higher vascular plants are characterized by the least diversity in all zonal areas of Western Siberia. On average, the flora of Western Siberia is poorer than in adjacent regions by about 1.5 times; the gap is especially large for the taiga and tundra zones. The fauna of Western Siberia is characterized by a higher relative diversity. So, in the four main orders of mammals in Western Siberia, there are 80 species, for Eastern Siberia and European Russia - 94 and 90, respectively. Species common with Eastern Siberia - 13, with European Russia - 16, common for all three regions - 51; found only in Western Siberia - no. The fauna of birds is distinguished by the greatest diversity, the main part of whose species in Western Siberia are migratory. In terms of the total number of bird species, Western Siberia is not significantly inferior to adjacent regions in any zonal area, and surpasses them in waterfowl and near-water ones.The main reason for the poverty of the flora and fauna of Western Siberia is most often considered the consequences of the Pleistocene glaciation, which was the most devastating on its territory, as well as the remoteness of mountain refugia that fed the migration flow in the Holocene.
Administrative division
On the territory of Western Siberia are located the Tyumen, Tomsk, Omsk, Novosibirsk, Kemerovo regions, as well as parts of the Kurgan, Chelyabinsk and Sverdlovsk regions and the Altai and Krasnoyarsk territories. The largest city in Western Siberia - Novosibirsk (1.5 million inhabitants) is located on the Ob River.Economic use(resource extraction, timber industry)
The most developed industries in Western Siberia are mining (oil, gas, coal) and forestry. At present, Western Siberia provides over 70% of the all-Russian oil and natural gas production, about 30% of coal production, and about 20% of timber harvested in the country.A powerful oil and gas production complex is currently operating on the territory of Western Siberia. The largest deposits of oil and natural gas are associated with a thick layer of sedimentary rocks of the West Siberian Plain. The area of oil and gas bearing lands is about 2 million km2. Forest and marsh landscapes, until the 1960s, completely untouched by industrial development and practically unexplored, are dissected for hundreds of kilometers by pipelines, roads, power lines, dotted with drilling sites, oiled with oil spills and oil products, covered with burnt areas and soaked forests that appeared as a result of the use obsolete technologies for the production and transportation of oil and gas.
It should be noted that Western Siberia, like no other in world region, replete with rivers, lakes and swamps. They contribute to the active migration of chemical pollutants entering the Ob River from numerous sources, which carries them into the Gulf of Ob and further into the Arctic Ocean, endangering the destruction of ecosystems remote from the areas of the oil and gas complex.
In contrast to the West Siberian Plain, the Kuznetsk mountain region stands out for its coal reserves: the Kuznetsk coal basin accounts for 40% of the country's industrial coal reserves. The main production centers are the cities of Leninsk-Kuznetsky and Prokopyevsk.
Prepared by E.A. Chelaznova
West Siberian Plain West Siberian Lowland, one of the largest low-lying accumulative plains the globe. It is located north of the low-hill plain of Kazakhstan and the Altai mountains, between the Urals in the west and the Central Siberian plateau in the east. Extending from north to south up to 2500 km, from W. to E. from 1000 to 1900 km; an area of about 2.6 million sq. km 2. The surface is flat, slightly dissected, with small height amplitudes. The heights of the lowlands of the northern and central regions do not exceed 50-150 m, low elevations (up to 220-300 m) are characteristic mainly of the western, southern, and eastern margins of the plain. A strip of hills also forms the so-called. Siberian Ridges, stretching in the middle part of the Z.-S. R. from the Ob almost to the Yenisei. Wide, flat spaces of interfluves predominate everywhere, with slight slopes of the surface, heavily waterlogged and in places complicated by moraine hills and ridges (in the north) or low sandy ridges (mainly in the south). Significant areas are occupied by flat ancient lake basins - woodlands. The river valleys form a relatively sparse network and in the upper reaches they are most often shallow hollows with poorly pronounced slopes. Only a few of the largest rivers flow in well-developed, deep (up to 50-80 m) valleys, with a steep right bank and a system of terraces on the left bank. Z.-S. R. formed within the epihercynian West Siberian plate, the basement of which is composed of intensely dislocated Paleozoic deposits. They are everywhere covered with a cover of loose marine and continental Meso-Cenozoic rocks (clays, sandstones, marls, etc.) with a total thickness of over 1000 m(in foundation depressions up to 3000-4000 m). The youngest Anthropogenic deposits in the south are alluvial and lacustrine, often covered by loess and loess-like loams; in the north - glacial, marine, and glacial-marine (capacity in places up to 200 m).
In the cover of loose deposits Z.-S. R. groundwater horizons are enclosed - fresh and mineralized (including brines), hot (up to 100-150 ° C) waters are also found (see West Siberian artesian basin). In the depths of Z.-S. R. the richest industrial deposits of oil and natural gas are enclosed (see the West Siberian oil and gas basin).
The climate is continental, quite severe. In winter, masses of cold continental air of temperate latitudes predominate over the plain, and in the warm season, an area of low pressure is formed and humid air masses from the North Atlantic often come here. The average annual temperatures are from -10.5°C in the north to 1-2°C in the south, the average temperatures in January are from -28 to -16°C, and in July from 4 to 22°C. The vegetation period in the extreme south reaches 175-180 days. The bulk of precipitation is brought by air masses from the west, mainly in July and August. Annual precipitation from 200-250 mm in tundra and steppe zones up to 500-600 mm in the forest zone. Snow cover thickness from 20-30 cm in the steppe up to 70-100 cm in the taiga of the Yenisei regions. The territory of the plain drains more than 2,000 rivers, the total length of which exceeds 250,000 km. km. The largest of them are the Ob, Yenisei, Irtysh. The main sources of river nutrition are melted snow water and summer-autumn rains; up to 70-80% of the annual runoff occurs in spring and summer. There are many lakes, the largest are Chany, Ubinskoye, and others. Some of the lakes in the southern regions are filled with salty and bitter-salty water. Large rivers are important navigable and rafting routes connecting the southern regions with the northern ones; The Yenisei, the Ob, the Irtysh, and the Tom have, in addition, large reserves of hydropower resources. The flatness of the relief Z. - S. r. determines a distinct latitudinal geographic zonality. A specific feature of most zones of Western Siberia is excessive soil moisture and, as a consequence, the wide distribution of marsh landscapes, which give way to solonetzes and solonchaks in the south. The north of the plain is a tundra zone, in which arctic, moss, and lichen landscapes form on arctic tundra and tundra gley soils, and in the south, shrub tundra. To the south there is a narrow strip of forest-tundra, where on peaty-gley, gley-podzolic and marsh soils complex landscape complexes of shrub tundra, spruce-larch woodlands, sphagnum and lowland bogs are developed. Most of the Z.-S. R. refers to the forest (forest-marsh) zone, within which coniferous taiga prevails on podzolic soils, consisting of spruce, fir, cedar, pine, Siberian larch; only in the extreme south of the zone are taiga massifs replaced by a strip of small-leaved birch and aspen forests. The total forest area exceeds 60 million hectares. ha, wood reserves 9 billion. m 3, and its annual growth is 100 million. m 3. The forest zone is distinguished by the wide development of raised ridge-hollow sphagnum bogs, which in some places account for more than 50% of the area. Of the animals of the forest zone, the following are typical: brown bear, lynx, wolverine, marten, otter, Siberian weasel, sable, elk, Siberian roe deer, squirrel, chipmunk, muskrat, and other representatives of the fauna of the European-Siberian subregion of the Palearctic. To the south of the subzone of small-leaved forests, there is a forest-steppe zone, where leached and ordinary chernozems, meadow-chernozem, dark gray forest and marsh soils, solonetzes, solods . The extreme southern part of the Z. - S. p. It occupies the steppe zone, in the north of which until recently forb feather grass steppes predominated, and in the south - feather grass-fescue steppes. Now these steppes, with their fertile chernozem and dark chestnut soils, have been plowed up, and only areas with saline soils in places have retained their virgin character. Lit.: West Siberian lowland. Essay on nature, M., 1963; Western Siberia, M., 1963. N. I. Mikhashov.
Big soviet encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .
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West Siberian Plain ... Wikipedia
Between the Urals in the west and the Central Siberian Plateau in the east. OK. 3 million km². The length from north to south is up to 2500 km, from west to east up to 1900 km. Height from 50 150 m in the northern and central parts to 300 m in the western, southern and ... ... Big Encyclopedic Dictionary
WESTERN SIBERIAN PLAIN, between the Urals in the west and the Central Siberian Plateau in the east. OK. 3 million km2. The length from north to south is up to 2500 km, from west to east up to 1900 km. Height from 50 150 m in the northern and central parts to 300 m in ... ... Russian history
One of the largest on earth. Takes b. h. Zap. Siberia, stretching from the coast of the Kara Sea in the north to the Kazakh uplands in the south, from the Urals in the west to the Central Siberian Plateau in the east. OK. 3 million km². Wide flat or ... Geographic Encyclopedia
Between the Urals in the west and the Central Siberian Plateau in the east About 3 million km2. The length from north to south is up to 2500 km, from west to east up to 1900 km. Height from 50 150 m in the northern and central parts to 300 m in the western, southern and eastern. ... ... encyclopedic Dictionary
West Siberian Plain- West Siberian Plain, West Siberian Lowland. One of the largest low-lying accumulative plains of the globe. It occupies most of Western Siberia, stretching from the coast of the Kara Sea in the north to the Kazakh uplands and ... Dictionary "Geography of Russia"
West Siberian Plain- West Siberian Plain ... Russian spelling dictionary
West Siberian Plain of the USSR. physical map - … Geographic atlas
West Siberian Lowland the third largest plain on our planet after the Russian one. 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 bounded from the north by the coastline of the sea, from the south by the hills of Kazakhstan and mountains, from the west by the eastern foothills of the Urals, and in the east by the valley of the Yenisei River.
The surface of the West Siberian Lowland is flat with a rather insignificant elevation difference. Small hills 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 a height of 50-150 meters above sea level.
On the entire surface of the plain there are flat areas of interfluves, as a result of which they are significantly waterlogged. In the northern part, small hills and sandy manes are sometimes found. Rather impressive areas on the territory of the West Siberian Lowland are occupied by ancient hollows, 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 had an impact on the nature of the relief of Western Siberia. The northern part of the plain was mainly affected by 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 on the territory of the West Siberian Lowland. Their total length is about 250 thousand kilometers. The largest are . They are not only navigable, but also used to generate energy. They feed mainly on meltwater 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: excessive moisture, flat relief, and the ability of peat, which is available here in large quantities, to hold 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 areas. Sufficient in all areas large areas occupied by lakes and swamps. are absent here, and the zone is rather insignificant.
A large area is occupied by the zone, 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 mostly coniferous. The forest-bog zone occupies about 60% of the territory of the West Siberian Lowland. The strip of coniferous forests is followed by a narrow zone of small-leaved (mainly birch) forests. The forest-steppe zone is formed in the conditions of a flat relief. Lying here at shallow depths are the cause of a large number of swamps. In the extreme southern part of the West Siberian Lowland is located, which is mostly plowed up.
In the flat southern regions of Western Siberia, a variety of manes are introduced - sandy ridges 3-10 meters high (sometimes up to 30 meters), covered with pine forests, and pegs - birch and aspen groves that are scattered among the steppes.
The West Siberian Lowland, which extends into Russia, in Western Siberia, is one of the three largest plains on our planet in terms of area. The natural wealth extracted in its regions is truly limitless.
The West Siberian Plain has a significant territory in Russia (here it occupies 2.6 million km 2 out of the total area of more than 3 million km 2) and is partially included in the Kazakhstan expanses. At the West Siberian lowland (as the plain is also called), the length from the northern limits to the southern ones is about 2500 km, and from western borders to the eastern ones - from 1 thousand km to 2 thousand km.
Its boundaries:
- in the south direction: with the Turgai dining country and Saryarka;
- in northern parts: with the Arctic Ocean;
- in the western direction: with the Urals;
- in the east: with the Central Siberian plateau along the Yenisei river valley;
Theory of education, the age of the plain
The plain is based on a young platform. It was formed in the Paleozoic (570-240 million years ago), while the Altai Ranges were formed during the Caledonian (490-360 million years ago) orogeny.
West Siberian Plain - characteristics and features.
Stages of formation of the West Siberian Plate:
- It began to form in the Upper Jurassic period (152-157 million years ago). Then, during the breaking and rebirth of the plate, a giant territory (approximately between the Urals and the Siberian platform) sank, which led to the emergence of a sedimentation (in which sedimentation occurs) basin. In the process of its development, the West Siberian Plate was repeatedly captured by the sea advancing on land as a result of subsidence. earth's crust or rising sea levels.
- At the end of the Lower Oligocene (the period from 33.9 to 23.03 million years ago), the sea left the West Siberian plate, and it became a giant lacustrine-alluvial (alluvial) plain.
- On average and late period Oligocene and in the Neogene (23.03 - 2.58 million years ago) in the north, the plate rose, but at a later time (from 2.6 million years and later) it sank.
The plate developed during the subsidence of vast expanses, which indicates the likelihood of oceanization not completely completed, and this is emphasized by very strong waterlogging.
Relief and landscape
The West Siberian Plain has a very uniform relief. Its predominant part is below 100 m above sea level. More common are alluvial-lacustrine and accumulative (formed as a result of uneven accumulation of river, lacustrine, marine and other sediments, products of volcanic activity) reliefs.
In the southern part, a denudation relief is observed (formed during the transfer of weathered rocks from elevated areas of the terrain to lower ones).
Extensive floodplains and huge swamps are characteristic, mainly in the north. The relief, formed by the influence of glaciers and the advance of the sea on land, is noted north of the Ob River. Severe soreness. Salt accumulation is observed mainly to the south. In the north, the uniform flat relief is disturbed by elevations up to 200-300 m.
The accumulation of peat is typical for swamps. The sandy upper layers are subject to deflation (fluttering and wind blowing of particles of loose rocks, snow, as well as their transfer and grinding during transfer). Permafrost (the thickness of the frozen layer is up to 600 m) is observed in Yamal and other peninsulas.
To the south, the area of relief created by the activity of glaciers is adjacent to lacustrine and lacustrine-alluvial plains. Between the rivers Tobol and Irtysh is the sloping Ishim plain.
Natural areas are marked in the landscape:
Tectonic structure of the plain
The tectonic structure of the plain is based on the West Siberian young plate. Its foundation was formed from richly distributed Paleozoic deposits. On top they have loose continental and marine rocks of the Meso-Cenozoic with a thickness of more than 1 km.
The latest deposits are in the southern part, they are anthropogenic - lacustrine and alluvial, often hidden by loess (mountain loose porous rocks) and loess-like loams.
In the north of the deposit:
- glacial;
- marine;
- ice-sea (there are more than 4 km thick).
Climate
The West Siberian Lowland has a continental climate, typical of the interior regions of large continents. On the plain, zonality in latitudes is clearly manifested. The features of the weather regime are strongly affected by the Arctic Ocean.
The nature of the winter climate in the plain
Indicators observed:
| polar latitudes | central part | South part | |
| Duration winter months | Up to 8; around 3 - polar night | Around 7 | 5-6 |
| Average t January, ᵒ С | – 23 – 30 | –19 –22 | –18 –22 |
| Time of snow cover | 8-9 months | Fluctuates between digit values at other latitudes | 5-6 months |
Features of the summer climate
In summer, Atlantic air masses come from the west. At the same time, cold air comes from the Arctic, and from the southern regions, Central Asia- its warm and dry streams.
The nature of summer in the plains:
- northern: short, cool, with an abundance of precipitation;
- central: warm and moderately humid;
- southern: arid, with lack of moisture; characterized by dry winds, dust storms.
The air in the middle of summer usually warms up to values: from +5 ᵒС in the north to +22 ᵒС - to the south. Precipitation occurs mainly in summer, with the greatest amount of up to 600 mm per year. This is seen in the forests. In other zones, to the south and north, the amount of precipitation becomes less, reaching up to 250 mm during the year.
Rivers
More than 2 thousand rivers drain the plain. Their total length is over 250 thousand km. The total flow of water is 1200 km3 per year. The rivers are fed by melted snow and rainwater. Therefore, the water runoff is most voluminous in the summer and spring months (70-80% of the annual amount). In winter, the rivers freeze, at this time the annual flow is about 10% of the total volume.
Large rivers of the plain are navigable. They have significant reserves of hydropower resources.
All rivers of the plain are characterized by a low flow rate and slight slopes.
Ob
This is a very significant, high-water river, one of the greatest water arteries of the earth. The length of the Ob is 3676 km. The area of the basin is approximately 3 million km2. After joining the Irtysh River, the Ob's water flow acquires a width of up to 3-4 km. Near the mouth it reaches 10 km, the depth reaches 40 km.
The main tributaries of the Ob:
- Irtysh;
- Vasyugan;
- Northern Sosva;
- Chumysh;
- Ket;
- Big Yugan;
and others.
Irtysh
This is the most significant tributary of the Ob. Its length is 4248 km. The area of the basin is 1643 km2. It starts in the mountains of Mongolia. For a long period, the Irtysh has practically no tributaries. Then, in the taiga area, the Tobol, Ishim and other large rivers flow into it.
Yenisei
It flows nearby eastern border West Siberian lowland. This water artery is the most abundant in Russia. The length is 4091 km. The area of the basin is about 2.6 km2. The river begins in the Tuvan Republic. There are rapids in the middle and upper currents. Below, when the Lower Tunguska flows into the Yenisei, the speed of water movement weakens. Islands of sand loomed in the riverbed.
The Yenisei River flows into the bay of the Kara Sea, called the Yenisei Bay. In the lower reaches, the depth of the river reaches 50 km. Therefore, seagoing vessels can rise through the waters further than 700 km without interference.
The main tributaries of the Yenisei:
- Angara;
- Lower Tunguska;
- Stony Tunguska.
The Krasnoyarsk and Sayano-Shushenskaya hydroelectric power stations were built on the river.
Taz
Flows in the Yamalo-Nenets Autonomous Okrug. It starts on the Siberian Ridges from the raised bog. It flows into the Taz Bay, while forming a multi-branched delta. Length - 1401 km. The area of the basin is 150 thousand km2. The width of the channel in the lower reaches reaches 1000 m, the depth is up to 14.5 m.
lakes
The West Siberian Plain is unusually rich in lakes, there are approximately 1 million of them. Their total area exceeds 100,000 km 2.
Most large lakes:
- Vats;
- Small Chans;
- Kulunda;
- Sartlan
and others.
There are many salty, bitter-salty and self-sustaining lakes (with a very high salt content). In the north of the lowland, there are often lakes with thermokarst origin. There are many small lakes, the area of each does not reach 1 km2.
Flora
Due to the vast area of the West Siberian Plain, many types of vegetation can be distinguished that grow in various natural zones.
Some are listed in the table:
| polar desert |
|
| Tundra |
|
| Forest-tundra of Siberia |
|
| woodlands |
|
| Mountain forest belt |
|
| Aspen-birch forests |
|
| Taiga |
|
| Steppe |
|
Fauna
The animal world is also very diverse.
About 500 species of vertebrates have been identified here, of which the species are:
- mammals - 80;
- birds - 350;
- amphibians - 7;
- fish - 60.
You can roughly describe the fauna in the table:
| polar desert | Because of the permafrost animal world this area is limited. Meet:
|
| Tundra | The same animals are found as in the polar desert, and others:
|
| Forest-tundra of Siberia | Animals of the polar desert live and such:
|
| woodlands | Many inhabitants of the forest-tundra are noted (the first 5 in the table) and:
|
| Mountain forest belt | There are inhabitants of woodlands, as well as:
|
| Aspen-birch forests |
|
| Taiga | Replete with previously listed representatives of the fauna - rodents, predators, birds |
| forest-steppe zone | Meet different types rodents, also
|
The ichthyofauna is extremely rich.
Here are just a few types of fish:
The groundwater
The West Siberian artesian megabasin is a huge reservoir of fresh groundwater with an area of almost 3 million km3. The geological reserves of fresh groundwater for household and drinking purposes are over 65 thousand km 3.
2 hydrogeological levels of the inner basin are distinguished, separated by a thick layer of marine sediments of a clay character.
In the upper floor in the central areas of the basin and to the north, the waters are mostly fresh, which can be used for water supply. IN southbound water reservoirs have a more diverse chemical composition. They are mineralized up to 10-15 g/l, which is associated with ongoing continental salinization.
In the lower floor of the artesian basin, the water-bearing layers are saturated, flowing to the surface along the edges of the basin, in the Ob-Yenisei interfluve. In this place, up to several hundred meters deep, there are fresh waters suitable for human drinking and household needs.
From the edges to the central part of the basin, there is an increase in the clay component of sediments, the process of water exchange worsens, and the mineral component of groundwater increases (80 g/l). Hot (reach 150 °C) waters come across at a distance of 2,500-3 km inland.
natural areas
The West Siberian Plain is so large that it includes 5 natural zones plus mountainous and low-mountain regions.
All of them have specific features and are quite clearly separated:
| Zones | Peculiarities |
| Tundra | Celebrated in the north of the Tyumen region Area - approximately 160,000 km 2 No forests There are moss, lichen-sphagnum, lichen and other tundras. |
| Forest-tundra | It is located in a southerly direction relative to the tundra with an area of about 100-150 km, representing an adjacent zone with signs of both taiga and tundra Combines swamps, light forests, shrub thickets |
| Forest (also can be called taiga or forest swamp) | The strip is about 1000 km long. Territorially includes up to 62% of all Western Siberia It is divided into subzones of the taiga according to the cardinal points: northern, southern, middle The predominant forests of this zone are dark coniferous An important element is swamps, here are the greatest wetlands in the world |
| Forest-steppe | There are forest and steppe plant communities There are meadows and marshes Solonchaks marked Birch and mixed forests grow (aspens with birches) Forbs observed |
| steppe | In the west of the Altai Territory, in the south of Omsk, in Novosibirsk region Characteristic: flat terrain, grassy vegetation, a minimum of trees |
| Altitudinal zonality | It is due to the significant height of the mountains. This includes lowland and mountainous areas:
|
Minerals
The West Siberian Plain is replete with all sorts of minerals. 140 very large deposits have been discovered within its limits.
Found in the bowels:
- gold;
- platinum;
- titanium;
- iridium;
- chromium;
- zirconium;
- bronze;
- molybdenum;
- silver;
- barium;
- mercury;
- manganese;
- coal;
- natural gas;
- peat;
- limestone;
- cesium;
- brown coal;
- strontium;
- calcium;
- tungsten;
- scandium;
- oil;
- ores.
Oil is produced everywhere in Western Siberia; in 2017, 340 wells were in operation. Marshes provide good ground for maintaining natural gas reserves, storing coal deposits and other valuable hydrocarbons. Very large reserves of shale, oil, and gas have been explored in the open spaces of the Middle Ob Lowland.
The Tazovo-Purskaya lowland is a significant region for the production and processing of natural gas and oil. The Yamal Peninsula is fraught with colossal reserves of "black gold", polymetallic and gas sources. Brown coal, potash salts, and iron ore are also mined here.
Dominant Heights
For the most part, they are not higher than 150 m. The lowest areas of the plain reach 50-100 m. They can be observed mainly in a northerly direction. Such lowlands as Purskaya, Nizhneobskaya and Nadymskaya, with Kondinskaya and Sredneobskaya hiding in its central part, are the lowest in the described geographical area.
The most high point plains is defined on the Priobsky plateau. It is located at an elevation of 317 m.
Regions
The Yamalo-Nenets and Khanty-Mansi Autonomous Regions, as well as several regions, are located on the plains:
- Tomsk;
- Tyumenskaya;
- Kemerovo;
- Omsk;
- Novosibirsk.
In these regions, industry is actively operating, enterprises for the extraction and processing of minerals have been set up. Regions often have large areas, often - abundant waterlogging. Partially, the Russian regions of Kurgan, Chelyabinsk, Sverdlovsk, as well as Kazakhstani: Akmola, Pavlodar, Kustanai and others are also located here.
Large cities located on the plain and their features
Most Big city― Novosibirsk (about 1 million 500 thousand inhabitants). This is a major transport hub of the country, one of the centers of scientific and cultural life.
Other significant cities of the West Siberian Lowland:
There is industry, engineering. There is an international airport.
Ecological situation and specially protected natural areas
We did not bypass the West Siberian Plain ecological problems:
| In the regions of oil production | Due to violations of the integrity of pipelines, oil and products of its processing enter the water and soil |
| In forestry areas |
|
| In agricultural landscapes |
|
| In the north | Degradation of reindeer vegetative pastures due to overgrazing |
Also topical is the problem of preserving spaces for hunting and habitats for the existence of fauna in nature.
For the purposes of conservation and research of natural landscapes, natural parks, reserves and similar objects, for example:
- nature reserves: Malaya Sosva, Verkhnetazovsky, Gydansky;
- natural parks: Kondinsky lakes, Deer streams, Siberian Uvaly;
- National parks: Pripyshminsky Bory and others.
The value of the plain in Russia and the world
The West Siberian Plain is one of the largest plains on the planet Earth. Here, countless deposits of minerals are stored in the bowels of the earth. Gigantic water resources are concentrated here. The area of swamps in total exceeds 600 thousand km 2, which is much more than the territories of France, Spain or Switzerland.
More than 60% of the oil treasures of this region are concentrated in the swamps, they are also the richest source of fresh water. The colossal reserves of bog peat are capable of sequestering carbon, while hindering the development of the greenhouse effect.
Most of the lowland area is covered by taiga. The forest potential of the West Siberian Lowland is very valuable for the development of the forest industry. These resources are more and more intensively involved in the sphere every year. economic development. The export of wood and lumber from Russia to other countries is increasing.
There is reason to believe that Western Siberia for Russia is the most prosperous region in terms of natural resources. Mineral resources regions have commercial value and are extremely important in the global economy. They are transported across railway and pipelines to the European part of Russia and further to other countries.
The landscapes of nature in Russia are magnificent and unique. The beautiful West Siberian Lowland, which has taken possession of almost the entire space of Western Siberia, is a plain with the richest mineral, water and forest resources. It is a very valuable region for Russian Federation and other countries of the world.
Article formatting: Lozinsky Oleg
Video about the West Siberian Plain
Features of the nature of the West Siberian Plain:
