Why is Western Siberia a plain? Physical Geography - Western Siberia (West Siberian Plain)

The West Siberian Plain is one of the largest flat areas in the world, covering approximately 80% of Western Siberia.

Features of nature

In terms of total area, the West Siberian Plain is surpassed only by the Amazon. The plain stretches from the coast of the Kara Sea south to the north of Kazakhstan. The total area of ​​the West Siberian Plain is about 3 million. km 2. Here, predominantly wide, gently-stepped and flat interfluves predominate, separating terraced valleys.

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

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

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

Flora of the West Siberian Plain

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

About 30% of the plain's area is occupied by tracts of coniferous trees, many of which are swampy. Smaller areas are covered with dark coniferous taiga - spruce, fir and cedar. Broad-leaved tree species are occasionally found in the southern regions. In the southern part there are very common birch forests, many of which are secondary.

Fauna of the West Siberian Plain

The vastness of the West Siberian Plain is home to more than 450 species of vertebrates, of which 80 species belong to mammals. Many species are protected by law because they belong to the category of rare and endangered. Recently, the fauna of the plain has been significantly enriched with acclimatized species - muskrat, brown hare, teledut squirrel, and American mink.

The reservoirs are inhabited mainly by carp and bream. In the eastern part of the West Siberian Plain, some eastern species are found: chipmunk, Djungarian hamster, etc. In most cases, the fauna of this territory is not much different from the fauna of the Russian Plain.

West Siberian Plain- the plain is located in northern Asia, occupies the entire western part of Siberia from the Ural Mountains in the west to the Central Siberian Plateau in the east. In the north it is limited by the coast of the Kara Sea, in the south it extends to the Kazakh small hills, in the southeast the West Siberian Plain, gradually rising, gives way to the foothills of Altai, Salair, Kuznetsk Altai and Mountain Shoria. The plain has the shape of a trapezoid tapering towards the north: the distance from its southern border to the northern reaches almost 2500 km, the width is from 800 to 1900 km, and the area is only slightly less than 3 million km².

The West Siberian Plain is the most populated and developed (especially in the south) part of Siberia. Within its borders are the Tyumen, Kurgan, Omsk, Novosibirsk and Tomsk regions, the eastern regions of the Sverdlovsk and Chelyabinsk regions, a significant part of the Altai Territory, the western regions of the Krasnoyarsk Territory (about 1/7 of the area of ​​Russia), as well as the northern and northeastern regions of Kazakhstan.

Relief and geological structure

The surface of the West Siberian Lowland is flat with a fairly insignificant difference in elevation. However, the relief of the plain is quite diverse. The lowest areas of the plain (50-100 m) are located mainly in the central (Kondinskaya and Sredneobskaya lowlands) and northern (Nizhneobskaya, Nadymskaya and Purskaya lowlands) parts. Along the western, southern and eastern outskirts stretch low (up to 200-250 m) hills: North Sosvinskaya and Turinskaya, Ishim Plain, Priobskoye and Chulym-Yenisei Plateau, Ket-Tymskaya, Verkhnetazovskaya and Lower Yenisei uplands. A clearly defined strip of hills is formed in the inner part of the Sibirskie Uvaly plain (average height - 140-150 m), stretching from the west from the Ob to the east to the Yenisei, and the Vasyuganskaya, parallel to them, is equal.

The relief of the plain is largely determined by its geological structure. At the base of the West Siberian Plain lies the epi-Hercynian West Siberian Plate, the foundation of which is composed of intensely dislocated Paleozoic sediments. The formation of the West Siberian plate began in the Upper Jurassic, when, as a result of breaking off, destruction and degeneration, a huge area between the Urals and the Siberian platform sank, and a huge sedimentation basin arose. During its development, the West Siberian Plate was repeatedly captured 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 gave way to subsidence in Quaternary time. The general course of development of the plate with the subsidence of colossal spaces resembles an incomplete process of oceanization. This feature of the slab is emphasized by the phenomenal development of wetlands.

Individual geological structures, despite the thick layer of sediments, are reflected in the relief of the plain: for example, the Verkhnetazovskaya and Lyulimvor hills correspond to gentle anticlinal uplifts, and the Barabinskaya and Kondinskaya lowlands are confined to the syneclises of the foundation of the plate. However, in Western Siberia, discordant (inversion) morphostructures are also common. These include, for example, the Vasyugan Plain, formed on the site of a gently sloping syneclise, and the Chulym-Yenisei Plateau, located in the zone of basement deflection.

The mantle of loose sediment contains horizons of groundwater - fresh and mineralized (including brine), and hot (up to 100-150°C) water is also found. There are industrial deposits of oil and natural gas (West Siberian oil and gas basin). In the area of ​​the Khanty-Mansi syneclise, Krasnoselsky, Salym and Surgut regions, in the layers of the Bazhenov formation at a depth of 2 km, there are the largest shale oil reserves in Russia.

Climate

The West Siberian Plain is characterized by a harsh, fairly continental climate. Its large extent from north to south determines a clearly defined climate zonation and significant differences in climatic conditions in the northern and southern parts of Western Siberia. The continental climate of Western Siberia is also significantly influenced by the proximity of the Arctic Ocean. The flat terrain facilitates the exchange of air masses between its northern and southern regions.

During the cold period, within the plain, there is an interaction between an area of ​​relatively high atmospheric pressure located over the southern part of the plain and an area of ​​low pressure, which in the first half of winter extends in the form of a trough of the Icelandic baric minimum over the Kara Sea and the northern peninsulas. In winter, continental air masses of temperate latitudes predominate, which come from Eastern Siberia or are formed locally as a result of cooling of the air over the plain.

Cyclones often pass through the border zone of areas of high and low pressure. Therefore, in winter the weather in the coastal provinces is very unstable; On the coast of Yamal and the Gydan Peninsula, strong winds occur, the speed of which reaches 35-40 m/sec. The temperature here is even slightly higher than in neighboring forest-tundra provinces, located between 66 and 69° N. w. However, further south, winter temperatures gradually rise again. In general, winter is characterized by stable low temperatures and few thaws. Minimum temperatures throughout Western Siberia are almost the same. Even near the southern border of the country, in Barnaul, there are frosts down to -50 -52°. Spring is short, dry and relatively cold; April, even in the forest-swamp zone, is not yet quite a spring month.

In the warm season, low pressure is established over Western Siberia, and an area of ​​higher pressure forms over the Arctic Ocean. In connection with this summer, weak northern or northeastern winds predominate and the role of westerly air transport noticeably increases. In May there is a rapid increase in temperatures, but often, when arctic air masses invade, there are returns of cold weather and frosts. The warmest month is July, the average temperature of which is from 3.6° on Bely Island to 21-22° in the Pavlodar region. The absolute maximum temperature is from 21° in the north (Bely Island) to 44° in the extreme southern regions (Rubtsovsk). High summer temperatures in the southern half of Western Siberia are explained by the arrival of heated continental air from the south - from Kazakhstan and Central Asia. Autumn comes late.

The duration of snow cover in the northern regions reaches 240-270 days, and in the south - 160-170 days. The thickness of the snow cover in the tundra and steppe zones in February is 20-40 cm, in the forest-swamp zone - from 50-60 cm in the west to 70-100 cm in the eastern Yenisei regions.

The harsh climate of the northern regions of Western Siberia contributes to soil freezing and widespread permafrost. On the Yamal, Tazovsky and Gydansky peninsulas, permafrost is found everywhere. In these areas of continuous (merged) distribution, the thickness of the frozen layer is very significant (up to 300-600 m), and its temperatures are low (in watershed areas - 4, -9°, in valleys -2, -8°). To the south, within the northern taiga to a latitude of approximately 64°, permafrost occurs in the form of isolated islands interspersed with taliks. Its power decreases, temperatures rise to 0.5 -1°, and the depth of summer thawing also increases, especially in areas composed of mineral rocks.

Hydrography

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

More than 2,000 rivers flow on the territory of the West Siberian Plain, the total length of which exceeds 250 thousand km. These rivers carry about 1,200 km³ of water into the Kara Sea annually - 5 times more than the Volga. The density of the river network is not very large and varies in different places depending on the topography and climatic features: in the Tavda basin it reaches 350 km, and in the Barabinsk forest-steppe - only 29 km per 1000 km². Some southern regions of the country with a total area of ​​more than 445 thousand km² belong to areas of closed drainage and are distinguished by an abundance of drainless lakes.

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

The rivers of Western Siberia, including the largest ones - the Ob, Irtysh and Yenisei, are characterized by slight slopes and low flow speeds. For example, the fall of the Ob riverbed in the area from Novosibirsk to the mouth over a distance of 3000 km is only 90 m, and its flow speed does not exceed 0.5 m/sec.

On the West Siberian Plain there are about one million lakes, the total area of ​​which is more than 100 thousand km². Based on the origin of the basins, they are divided into several groups: those occupying the primary unevenness of the flat terrain; thermokarst; moraine-glacial; lakes of river valleys, which in turn are divided into floodplain and oxbow lakes. Peculiar lakes - "fogs" - are found in the Ural part of the plain. They are located in wide valleys, overflow in the spring, sharply reducing their size in the summer, and by autumn many disappear altogether. In the southern regions, lakes are often 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, permafrost and the ability of peat, which is available here in large quantities, to retain a significant amount of water.

Natural areas

The large extent from north to south contributes to a pronounced latitudinal zonality in the distribution of soils and vegetation cover. Within the country there are gradually replacing one another tundra, forest-tundra, forest-swamp, forest-steppe, steppe and semi-desert (in the extreme south) zones. In all zones, lakes and swamps occupy fairly large areas. Typical zonal landscapes are located on dissected and better drained upland and riverine areas. In poorly drained interfluve spaces, where drainage is difficult and the soils are usually highly moist, swamp landscapes predominate in the northern provinces, and landscapes formed under the influence of saline groundwater in the south.

A large area is occupied by the tundra zone, which is explained by the northern position of the West Siberian Plain. To the south is the forest-tundra zone. The forest-swamp zone occupies about 60% of the territory of the West Siberian Plain. There are no broad-leaved and coniferous-deciduous forests here. The strip of coniferous forests is followed by a narrow zone of small-leaved (mainly birch) forests. The increase in climate continentality causes a relatively sharp transition, compared to the East European Plain, from forest-swamp landscapes to dry steppe spaces in the southern regions of the West Siberian Plain. Therefore, the width of the forest-steppe zone in Western Siberia is much smaller than on the East European Plain, and the tree species found in it are mainly birch and aspen. In the extreme southern part of the West Siberian Lowland there is a steppe zone, which is mostly plowed. The flat landscape of the southern regions of Western Siberia is added to the variety of manes - sandy ridges 3-10 meters in height (sometimes up to 30 meters), covered with pine forest.

Gallery

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Landscape of the West Siberian Plain

Steppe in the outskirts of Mariinsk1.jpg

Mariinsky forest-steppes

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Notes

Links

• West Siberian Plain // Great Soviet Encyclopedia: [in 30 volumes] / ch. ed. A. M. Prokhorov. - 3rd ed. - M. : Soviet encyclopedia, 1969-1978.
• in the book: N. A. Gvozdetsky, N. I. Mikhailov. Physical geography of the USSR. M., 1978.
• Kröner, A. (2015) The Central Asian Orogenic Belt.

An excerpt characterizing the West Siberian Plain

It was one of those March nights when winter seems to want to take its toll and pours out its last snows and storms with desperate anger. To meet the German doctor from Moscow, who was expected every minute and for whom a support was sent to the main road, to the turn to the country road, horsemen with lanterns were sent to guide him through the potholes and jams.
Princess Marya had left the book long ago: she sat silently, fixing her radiant eyes on the wrinkled face of the nanny, familiar to the smallest detail: on a strand of gray hair that had escaped from under a scarf, on the hanging pouch of skin under her chin.
Nanny Savishna, with a stocking in her hands, in a quiet voice told, without hearing or understanding her own words, what had been told hundreds of times about how the late princess in Chisinau gave birth to Princess Marya, with a Moldavian peasant woman instead of her grandmother.
“God have mercy, you never need a doctor,” she said. Suddenly a gust of wind hit one of the exposed frames of the room (by the will of the prince, one frame was always displayed with larks in each room) and, knocking off the poorly closed bolt, fluttered the damask curtain, and, smelling cold and snow, blew out the candle. Princess Marya shuddered; The nanny, having put down the stocking, went to the window and leaned out and began to catch the folded frame. The cold wind ruffled the ends of her scarf and the gray, stray strands of hair.
- Princess, mother, someone is driving along the road ahead! - she said, holding the frame and not closing it. - With lanterns, it should be, doctor...
- Oh my god! God bless! - said Princess Marya, - we must go meet him: he doesn’t know Russian.
Princess Marya threw on her shawl and ran towards those traveling. When she passed the front hall, she saw through the window that some kind of carriage and lanterns were standing at the entrance. She went out onto the stairs. There was a tallow candle on the railing post and it was flowing from the wind. The waiter Philip, with a frightened face and another candle in his hand, stood below, on the first landing of the stairs. Even lower, around the bend, along the stairs, moving footsteps in warm boots could be heard. And some familiar voice, as it seemed to Princess Marya, said something.
- God bless! - said the voice. - And father?
“They’ve gone to bed,” answered the voice of the butler Demyan, who was already downstairs.
Then the voice said something else, Demyan answered something, and footsteps in warm boots began to approach faster along the invisible bend of the stairs. "This is Andrey! - thought Princess Marya. No, this cannot be, it would be too unusual,” she thought, and at the same moment as she was thinking this, on the platform on which the waiter stood with a candle, the face and figure of Prince Andrei appeared in a fur coat with a collar sprinkled with snow. Yes, it was him, but pale and thin, and with a changed, strangely softened, but alarming expression on his face. He walked onto the stairs and hugged his sister.
-You didn’t receive my letter? - he asked, and without waiting for an answer, which he would not have received, because the princess could not speak, he returned, and with the obstetrician, who entered after him (he met with him at the last station), with quick steps he again entered the the stairs and hugged his sister again. - What fate! - he said, “Dear Masha,” and, throwing off his fur coat and boots, he went to the princess’s quarters.

The little princess was lying on pillows, wearing a white cap. (Suffering had just released her.) Black hair curled in strands around her sore, sweaty cheeks; her rosy, lovely mouth with a sponge covered with black hairs was open, and she smiled joyfully. Prince Andrei entered the room and stopped in front of her, at the foot of the sofa on which she was lying. Brilliant eyes, looking childish, scared and excited, stopped at him without changing expression. “I love you all, I haven’t done harm to anyone, why am I suffering? help me,” her expression said. She saw her husband, but did not understand the significance of his appearance now before her. Prince Andrei walked around the sofa and kissed her on the forehead.
“My darling,” he said: a word he had never spoken to her. - God is merciful. “She looked at him questioningly, childishly and reproachfully.
“I expected help from you, and nothing, nothing, and you too!” - said her eyes. She wasn't surprised that he came; she did not understand that he had arrived. His arrival had nothing to do with her suffering and its relief. The torment began again, and Marya Bogdanovna advised Prince Andrei to leave the room.
The obstetrician entered the room. Prince Andrei went out and, meeting Princess Marya, again approached her. They started talking in a whisper, but every minute the conversation fell silent. They waited and listened.
“Allez, mon ami, [Go, my friend,” said Princess Marya. Prince Andrey again went to his wife and sat down in the next room, waiting. Some woman came out of her room with a frightened face and was embarrassed when she saw Prince Andrei. He covered his face with his hands and sat there for several minutes. Pathetic, helpless animal groans were heard from behind the door. Prince Andrei stood up, went to the door and wanted to open it. Someone was holding the door.
- You can’t, you can’t! – a frightened voice said from there. – He began to walk around the room. The screams stopped and a few seconds passed. Suddenly a terrible scream - not her scream, she could not scream like that - was heard in the next room. Prince Andrei ran to the door; the scream stopped, and the cry of a child was heard.
“Why did they bring the child there? thought Prince Andrei at the first second. Child? Which one?... Why is there a child there? Or was it a baby born? When he suddenly realized all the joyful meaning of this cry, tears choked him, and he, leaning with both hands on the windowsill, sobbed, began to cry, as children cry. The door opened. The doctor, with his shirt sleeves rolled up, without a frock coat, pale and with a shaking jaw, left the room. Prince Andrey turned to him, but the doctor looked at him in confusion and, without saying a word, walked past. The woman ran out and, seeing Prince Andrei, hesitated on the threshold. He entered his wife's room. She lay dead in the same position in which he had seen her five minutes ago, and the same expression, despite the fixed eyes and the paleness of her cheeks, was on that charming, childish face with a sponge covered with black hairs.
“I love you all and have never done anything bad to anyone, so what did you do to me?” her lovely, pitiful, dead face spoke. In the corner of the room, something small and red grunted and squeaked in Marya Bogdanovna’s white, shaking hands.

Two hours after this, Prince Andrei entered his father’s office with quiet steps. The old man already knew everything. He stood right at the door, and as soon as it opened, the old man silently, with his senile, hard hands, like a vice, grabbed his son’s neck and sobbed like a child.

Three days later the funeral service was held for the little princess, and, bidding farewell to her, Prince Andrei ascended the steps of the coffin. And in the coffin was the same face, although with closed eyes. “Oh, what have you done to me?” it said everything, and Prince Andrei felt that something was torn away in his soul, that he was guilty of a guilt that he could not correct or forget. He couldn't cry. The old man also entered and kissed her wax hand, which lay calmly and high on the other, and her face said to him: “Oh, what and why did you do this to me?” And the old man turned away angrily when he saw this face.

Five days later, the young Prince Nikolai Andreich was baptized. The mother held the diapers with her chin while the priest smeared the boy’s wrinkled red palms and steps with a goose feather.
The godfather grandfather, afraid to drop him, shuddering, carried the baby around the dented tin font and handed him over to his godmother, Princess Marya. Prince Andrei, frozen with fear that the child would not be drowned, sat in another room, waiting for the end of the sacrament. He looked joyfully at the child when the nanny carried him out to him, and nodded his head approvingly when the nanny told him that a piece of wax with hairs thrown into the font did not sink, but floated along the font.

Rostov's participation in Dolokhov's duel with Bezukhov was hushed up through the efforts of the old count, and Rostov, instead of being demoted, as he expected, was appointed adjutant to the Moscow governor general. As a result, he could not go to the village with his entire family, but remained in his new position all summer in Moscow. Dolokhov recovered, and Rostov became especially friendly with him during this time of his recovery. Dolokhov lay sick with his mother, who loved him passionately and tenderly. The old woman Marya Ivanovna, who fell in love with Rostov for his friendship with Fedya, often told him about her son.
“Yes, Count, he is too noble and pure of soul,” she used to say, “for our current, corrupted world.” Nobody likes virtue, it hurts everyone's eyes. Well, tell me, Count, is this fair, is this fair on Bezukhov’s part? And Fedya, in his nobility, loved him, and now he never says anything bad about him. In St. Petersburg, these pranks with the police officer were something they joked about, because they did it together? Well, Bezukhov had nothing, but Fedya bore everything on his shoulders! After all, what did he endure! Suppose they returned it, but how could they not return it? I think there weren’t many brave men and sons of the fatherland like him there. Well now - this duel! Do these people have a sense of honor? Knowing that he is the only son, challenge him to a duel and shoot so straight! It's good that God had mercy on us. And for what? Well, who doesn’t have intrigue these days? Well, if he is so jealous? I understand, because he could have made me feel it before, otherwise it went on for a year. And so, he challenged him to a duel, believing that Fedya would not fight because he owed him. What baseness! That's disgusting! I know you understood Fedya, my dear count, that’s why I love you with my soul, believe me. Few people understand him. This is such a high, heavenly soul!
Dolokhov himself often, during his recovery, spoke to Rostov such words that could not have been expected from him. “They consider me an evil person, I know,” he used to say, “so be it.” I don’t want to know anyone except those I love; but whom I love, I love him so much that I will give my life, and I will crush the rest if they stand on the road. I have an adored, unappreciated mother, two or three friends, including you, and I pay attention to the rest only as much as they are useful or harmful. And almost everyone is harmful, especially women. Yes, my soul,” he continued, “I have met loving, noble, sublime men; but I haven’t met women yet, except for corrupt creatures - countesses or cooks, it doesn’t matter. I have not yet encountered that heavenly purity and devotion that I look for in a woman. If I found such a woman, I would give my life for her. And these!...” He made a contemptuous gesture. “And do you believe me, if I still value life, then I value it only because I still hope to meet such a heavenly being who would revive, purify and exalt me.” But you don't understand this.
“No, I understand very much,” answered Rostov, who was under the influence of his new friend.

In the fall, the Rostov family returned to Moscow. At the beginning of winter, Denisov also returned and stayed with the Rostovs. This first time of the winter of 1806, spent by Nikolai Rostov in Moscow, was one of the happiest and most cheerful for him and for his entire family. Nikolai brought many young people with him to his parents’ house. Vera was twenty years old, a beautiful girl; Sonya is a sixteen-year-old girl in all the beauty of a newly blossoming flower; Natasha is half a young lady, half a girl, sometimes childishly funny, sometimes girlishly charming.
In the Rostov house at that time there was some kind of special atmosphere of love, as happens in a house where there are very nice and very young girls. Every young man who came to the Rostovs’ house, looking at these young, receptive, smiling girlish faces for something (probably at their happiness), at this animated running around, listening to this inconsistent, but affectionate to everyone, ready for anything, hope-filled babble of a woman The youth, listening to these inconsistent sounds, now singing, now music, experienced the same feeling of readiness for love and expectation of happiness, which the youth of the Rostov house themselves experienced.
Among the young people introduced by Rostov, one of the first was Dolokhov, who was liked by everyone in the house, with the exception of Natasha. She almost quarreled with her brother over Dolokhov. She insisted that he was an evil person, that in the duel with Bezukhov Pierre was right, and Dolokhov was to blame, that he was unpleasant and unnatural.
“I don’t understand anything,” Natasha shouted with stubborn willfulness, “he’s angry and without feelings.” Well, I love your Denisov, he was a carouser and that’s all, but I still love him, so I understand. I don’t know how to tell you; He has everything planned, and I don’t like it. Denisova...
“Well, Denisov is a different matter,” answered Nikolai, making him feel that in comparison with Dolokhov, even Denisov was nothing, “you need to understand what kind of soul this Dolokhov has, you need to see him with his mother, this is such a heart!”
“I don’t know this, but I feel awkward with him.” And do you know that he fell in love with Sonya?
- What nonsense...
- I'm sure you'll see. – Natasha’s prediction came true. Dolokhov, who did not like the company of ladies, began to visit the house often, and the question of who he was traveling for was soon (although no one spoke about it) was resolved so that he was traveling for Sonya. And Sonya, although she would never have dared to say this, knew this and every time, like a redneck, she blushed when Dolokhov appeared.
Dolokhov often dined with the Rostovs, never missed a performance where they were present, and attended adolescentes [teenagers] balls at Yogel’s, where the Rostovs always attended. He paid preferential attention to Sonya and looked at her with such eyes that not only she could not stand this look without blushing, but also the old countess and Natasha blushed when they noticed this look.
It was clear that this strong, strange man was under the irresistible influence exerted on him by this dark, graceful, loving girl.
Rostov noticed something new between Dolokhov and Sonya; but he did not define to himself what kind of new relationship this was. “They are all in love with someone there,” he thought about Sonya and Natasha. But he was not as comfortable with Sonya and Dolokhov as before, and he began to be at home less often.
Since the autumn of 1806, everything again started talking about the war with Napoleon even more fervently than last year. Not only were recruits appointed, but also 9 more warriors out of a thousand. Everywhere they cursed Bonaparte with anathema, and in Moscow there was only talk about the upcoming war. For the Rostov family, the whole interest of these preparations for war lay only in the fact that Nikolushka would never agree to stay in Moscow and was only waiting for the end of Denisov’s leave in order to go with him to the regiment after the holidays. The upcoming departure not only did not prevent him from having fun, but also encouraged him to do so. He spent most of his time outside the house, at dinners, evenings and balls.

The eastern territories of Russian Asia open from the Ural Mountains to the West Siberian Plain. Its settlement by Russians began in the 16th century, from the time of Ermak’s campaign. The expedition's route ran from the south of the plain.

These territories are still the most densely populated. However, we must remember that already in the 11th century the Novgorodians established trade relations with the population on the lower Ob.

Geographical position

The West Siberian Plain is washed from the north by the harsh Kara Sea. In the east, along the border of the Yenisei River basin, it neighbors the Central Siberian Plateau. The southeast is protected by the snowy foothills of Altai. In the south, the Kazakh small hills became the border of flat territories. The western border, as stated above, is the oldest mountains of Eurasia - the Ural Mountains.

Relief and landscape of the plain: features

A unique feature of the plain is that all the heights on it are very weakly expressed, both in absolute and relative values. The area of ​​the West Siberian Plain, very low-lying, with many river channels, is swampy on 70 percent of the territory.

The lowland stretches from the shores of the Arctic Ocean to the southern steppes of Kazakhstan and almost all is located within the territory of our country. The plain provides a unique opportunity to see five natural zones with their characteristic landscape and climate conditions.

The relief is typical of low-lying river basins. Small hills alternating with swamps occupy the interfluve areas. The south is dominated by areas with saline groundwater.

Natural areas, cities and plain regions

Western Siberia is represented by five natural zones.

(Swampy area in the tundra of the Vasyugan swamps, Tomsk region)

The tundra occupies a narrow strip in the north of the Tyumen region and almost immediately turns into forest-tundra. In the extreme northern areas you can find massifs of a combination of lichens and mosses of Western Siberia. The area is dominated by swampy terrain, turning into open forest-tundra. Vegetation here includes larch and bushes.

The taiga of Western Siberia is characterized by dark coniferous zones with a variety of cedar, northern spruce and fir. Occasionally you can find pine forests occupying areas between the swamps. Most of the lowland landscape is occupied by endless swamps. One way or another, the whole of Western Siberia is characterized by swampiness, but there is also a unique natural massif here - the largest swamp in the world, the Vasyugan swamp. It occupied large territories in the southern taiga.

(Forest-steppe)

Closer to the south, nature changes - the taiga brightens, turning into forest-steppe. Aspen-birch forests and meadows with coppice appear. The Ob basin is decorated with pine island forests that arose naturally.

The steppe zone occupies the south of the Omsk and southwestern parts of the Novosibirsk regions. Also, the area of ​​distribution of the steppe reaches the western part of the Altai Territory, which includes the Kulundinskaya, Aleiskaya and Biyskaya steppes. The territory of ancient water drainages is occupied by pine forests

(Fields in the taiga of the Tyumen region, Yugra)

The West Siberian Plain provides the opportunity for active land use. It is very rich in oil and almost all of it is lined with production rigs. The region's developed economy attracts new residents. Large cities in the northern and central parts of the West Siberian Plain are well known: Urengoy, Nefteyugansk, Nizhnevartovsk. In the south are the cities of Tomsk, Tyumen, Kurgan, Omsk.

Rivers and lakes of the plain

(Yenisei River on hilly-flat terrain)

Rivers flowing through the West Siberian Lowland flow into the Kara Sea. The Ob is not only the longest river of the plain, but together with its tributary the Irtysh, it is the longest water artery in Russia. However, there are also rivers on the plain that do not belong to the Obi basin - Nadym, Pur, Taz and Tobol.

The territory is rich in lakes. They are divided into two groups according to the nature of their occurrence: some were formed in pits dug by a glacier passing through the lowlands, and some - in places of ancient swamps. The area holds the world record for swampiness.

Plain climate

Western Siberia in its north is covered with permafrost. A continental climate is observed throughout the plain. Most of the plain's territory is very susceptible to the influence of its formidable neighbor - the Arctic Ocean, whose air masses unhindered dominate the lowland region. Its cyclones dictate precipitation and temperature patterns. In areas of the plain where the Arctic, subarctic and temperate zones converge, cyclones often occur, leading to rain. In winter, cyclones generated at the junctions of the temperate and arctic zones soften the frosts in the north of the plains.

More precipitation falls in the north of the plain - up to 600 ml per year. Temperatures in the north in January on average do not rise above 22°C, in the south at the same time frosts reach 16°C. In July in the north and south of the plain, it is 4°C and 22°C, respectively.

The plain has the shape of a trapezoid tapering towards the north: the distance from its southern border to the northern reaches almost 2500 km, the width is from 800 to 1900 km, and the area is only 2.7 million km².

The West Siberian Plain is the most populated and developed (especially in the south) part of Siberia. Within its borders are the Tyumen, Kurgan, Omsk, Novosibirsk and Tomsk regions, the Yamalo-Nenets and Khanty-Mansi Autonomous Okrugs, the eastern regions of the Sverdlovsk and Chelyabinsk regions, a significant part of the Altai Territory, the western regions of the Krasnoyarsk Territory (about 1/7 of the area of ​​Russia). In the Kazakh part, within its boundaries there are areas of the North Kazakhstan, Akmola, Pavlodar, Kustanai and East Kazakhstan regions of Kazakhstan.

Relief and geological structure

The surface of the West Siberian Lowland is flat with a fairly insignificant difference in elevation. However, the relief of the plain is quite diverse. The lowest areas of the plain (50-100 m) are located mainly in the central (Kondinskaya and Sredneobskaya lowlands) and northern (Lower Obskaya, Nadymskaya and Purskaya lowlands) parts. Along the western, southern and eastern outskirts there are low (up to 200-250 m) hills: the North Sosvinskaya and Turinskaya, Ishim plains, the Priobskoye and Chulym-Yenisei plateaus, the Ketsko-Tymskaya, Verkhnetazovskaya and Lower Yenisei uplands. A clearly defined strip of hills is formed in the inner part of the plain by the Siberian Uvals (average height - 140-150 m), stretching from the west from the Ob to the east to the Yenisei, and the Vasyugan Plain parallel to them.

The relief of the plain is largely determined by its geological structure. At the base of the West Siberian Plain lies the epi-Hercynian West Siberian Plate, the foundation of which is composed of intensely dislocated Paleozoic sediments. The formation of the West Siberian plate began in the Upper Jurassic, when, as a result of breaking off, destruction and degeneration, a huge area between the Urals and the Siberian platform sank, and a huge sedimentation basin arose. During its development, the West Siberian Plate was repeatedly captured 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 gave way to subsidence in Quaternary time. The general course of development of the plate with the subsidence of colossal spaces resembles an incomplete process of oceanization. This feature of the slab is emphasized by the phenomenal development of wetlands.

Individual geological structures, despite the thick layer of sediments, are reflected in the relief of the plain: for example, the Verkhnetazovskaya and Lyulimvor hills correspond to gentle anticlinal uplifts, and the Barabinskaya and Kondinskaya lowlands are confined to the syneclises of the foundation of the plate. However, in Western Siberia, discordant (inversion) morphostructures are also common. These include, for example, the Vasyugan Plain, formed on the site of a gently sloping syneclise, and the Chulym-Yenisei Plateau, located in the zone of basement deflection.

The mantle of loose sediment contains horizons of groundwater - fresh and mineralized (including brine), and hot (up to 100-150°C) water is also found. There are industrial deposits of oil and natural gas (West Siberian oil and gas basin). In the area of ​​the Khanty-Mansi syneclise, Krasnoselsky, Salym and Surgut regions, in the layers of the Bazhenov formation at a depth of 2 km, there are the largest shale oil reserves in Russia.

Climate

The West Siberian Plain is characterized by a harsh, fairly continental climate. Its large extent from north to south determines a clearly defined climate zonation and significant differences in climatic conditions in the northern and southern parts of Western Siberia. The continental climate of Western Siberia is also significantly influenced by the proximity of the Arctic Ocean. The flat terrain facilitates the exchange of air masses between its northern and southern regions.

During the cold period, within the plain, there is an interaction between an area of ​​relatively high atmospheric pressure located over the southern part of the plain and an area of ​​low pressure, which in the first half of winter extends in the form of a trough of the Icelandic baric minimum over the Kara Sea and the northern peninsulas. In winter, continental air masses of temperate latitudes predominate, which come from Eastern Siberia or are formed locally as a result of cooling of the air over the plain.

Cyclones often pass through the border zone of areas of high and low pressure. Therefore, in winter the weather in the coastal provinces is very unstable; On the coast of Yamal and the Gydan Peninsula, strong winds occur, the speed of which reaches 35-40 m/sec. The temperature here is even slightly higher than in neighboring forest-tundra provinces, located between 66 and 69° N. w. However, further south, winter temperatures gradually rise again. In general, winter is characterized by stable low temperatures and few thaws. Minimum temperatures throughout Western Siberia are almost the same. Even near the southern border of the country, in Barnaul, there are frosts down to −50…−52°. Spring is short, dry and relatively cold; April, even in the forest-swamp zone, is not yet quite a spring month.

In the warm season, low pressure is established over Western Siberia, and an area of ​​higher pressure forms over the Arctic Ocean. In connection with this summer, weak northern or northeastern winds predominate and the role of westerly air transport noticeably increases. In May there is a rapid increase in temperatures, but often, when arctic air masses invade, there are returns of cold weather and frosts. The warmest month is July, the average temperature of which is from 3.6° on Bely Island to 21-22° in the Pavlodar region. The absolute maximum temperature is from 21° in the north (Bely Island) to 44° in the extreme southern regions (Rubtsovsk). High summer temperatures in the southern half of Western Siberia are explained by the arrival of heated continental air from the south - from Kazakhstan and Central Asia. Autumn comes late.

The duration of snow cover in the northern regions reaches 240-270 days, and in the south - 160-170 days. The thickness of the snow cover in the tundra and steppe zones in February is 20-40 cm, in the forest-swamp zone - from 50-60 cm in the west to 70-100 cm in the eastern Yenisei regions.

The harsh climate of the northern regions of Western Siberia contributes to soil freezing and widespread permafrost. On the Yamal, Tazovsky and Gydansky peninsulas, permafrost is found everywhere. In these areas of continuous (merged) distribution, the thickness of the frozen layer is very significant (up to 300-600 m), and its temperatures are low (in watershed areas - 4. -9°, in valleys -2. -8°). To the south, within the northern taiga to a latitude of approximately 64°, permafrost occurs in the form of isolated islands interspersed with taliks. Its power decreases, temperatures rise to 0.5–1°, and the depth of summer thawing also increases, especially in areas composed of mineral rocks.

Hydrography

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

More than 2,000 rivers flow on the territory of the West Siberian Plain, the total length of which exceeds 250 thousand km. These rivers carry about 1,200 km³ of water into the Kara Sea annually - 5 times more than the Volga. The density of the river network is not very large and varies in different places depending on the topography and climatic features: in the Tavda basin it reaches 350 km, and in the Barabinsk forest-steppe - only 29 km per 1000 km². Some southern regions of the country with a total area of ​​more than 445 thousand km² belong to areas of closed drainage and are distinguished by an abundance of drainless lakes.

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

The rivers of Western Siberia, including the largest ones - the Ob, Irtysh and Yenisei, are characterized by slight slopes and low flow speeds. For example, the fall of the Ob riverbed in the area from Novosibirsk to the mouth over a distance of 3000 km is only 90 m, and its flow speed does not exceed 0.5 m/sec.

On the West Siberian Plain there are about one million lakes, the total area of ​​which is more than 100 thousand km². Based on the origin of the basins, they are divided into several groups: those occupying the primary unevenness of the flat terrain; thermokarst; moraine-glacial; lakes of river valleys, which in turn are divided into floodplain and oxbow lakes. Peculiar lakes - “fogs” - are found in the Ural part of the plain. They are located in wide valleys, overflow in the spring, sharply reducing their size in the summer, and by autumn many disappear altogether. In the southern regions, lakes are often 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, permafrost and the ability of peat, which is available here in large quantities, to retain a significant amount of water.

Natural areas

The large extent from north to south contributes to a pronounced latitudinal zonality in the distribution of soils and vegetation cover. Within the country there are gradually replacing one another

The authors of all physical-geographical zoning schemes highlight Western Siberia with an area of ​​about 3 million sq. km. the same. Its boundaries coincide with the contours of the EpiPaleozoic West Siberian Plate. The geomorphological boundaries are also clearly expressed, coinciding mainly with the 200 m isohypsum, and in the north - with the coastline of the bays (lips) of the Kara Sea. Only the borders with the North Siberian and Turan plains are drawn.

Geological development and structure. In the Precambrian, the small West Siberian Platform and the foundation of the western part of the Siberian Platform were formed (approximately up to the line coinciding with the bed of the Taz River). The Ural geosyncline formed between the East European and West Siberian platforms, and the Yenisei geosyncline formed between the Siberian platforms. During their evolution in the Paleozoic, folded structures were formed along the outskirts of the West Siberian Platform: Baikalides west of the Yenisei Ridge, Salairids north of the Kuznetsk Alatau, Caledonides north of the western part of the Kazakh hills. These disparate structures were united by Hercynian folded areas, which also directly merged with the Hercynides of the Urals, Western (Rudny) Altai and the eastern part of the Kazakh hillocks. Thus, the nature of the West Siberian plate can be understood in two ways. Considering the “patchwork” nature of its foundation, it is often called heterogeneous, but since most of it was formed in the Paleozoic, the plate is considered Epipaleozoic. Noting the decisive role of the Hercynian folding, the slab is laid epihercynian.

Along with the long processes of formation of the foundation, in the Paleozoic (as well as the Triassic and Early Jurassic) the cover was created for just as long. In this regard, Paleozoic-Early Jurassic strata deposited on top of folded structures are usually classified into a special, “intermediate” or “transitional” floor (or complex), which geologists attribute either to the foundation or to the cover. It is believed that the present cover was formed only in the Meso-Cenozoic (starting from the mid-Jurassic period). The deposits of the cover overlapped the border zones of neighboring folded structures (the Siberian Platform, the Salairides of the Kuznetsk Alatau, the Caledonides and Hercynides of the Rudny Altai, Kazakhstan, and the Urals) and noticeably expanded the territory of the West Siberian Plate.

Crystalline folded foundation The plate consists of ancient (Precambrian and Paleozoic) metamorphic (schists, gneisses, granite gneisses, marbles), volcanic and sedimentary rocks. All of them are crushed into complex folds, broken into blocks by faults, and broken through by intrusions of acidic (granitoids) and basic (gabbroids) composition. The surface relief of the foundation is very complex. If you mentally remove the deposits of the cover, a sharply dissected surface of the mountain structure will be exposed with height amplitudes of 1.5 km in the peripheral parts and significantly larger ones in the north of the axial zone. The depths of the foundation naturally increase towards the axial zone and within this zone in the northern direction - from –3 to –8...-10 km, according to some data and more. The ancient West Siberian platform is fragmented into many blocks, most of which are deeply depressed, and some (for example, the Berezovsky block) are relatively elevated and can be traced on the surface (the Berezovsky Upland with maximum absolute heights of over 200 m). The margins of the West Siberian plate correspond to the slopes of neighboring folded structures, which are a kind of “shields”. In the internal parts of the plate there are syneclises (Omsk, Khanty-Mansiysk, Tazovsk and others), separated uplifts ( Vasyuganskoe) and vaults(Surgutsky, Nizhnevartovsky, etc.). Within the Kemerovo region there is part Teguldet depression with depths up to –2.5 km, strongly reminiscent of the Minusinsk depression.

“Intermediate floor consists of weakly dislocated and weakly metamorphosed strata of Paleozoic rocks overlying the basement of pre-Hercynian age (they are absent within the Hercynian structures), as well as trap rocks of the Triassic and coal-bearing terrigenous rocks of the Early Jurassic. At the end of the Permian and Triassic, a vast zone of lithospheric extension arose in Siberia. It covered the Tunguska syneclise of the Siberian Platform and submeridionally oriented zones between the Urals and the Irtysh and Poluy rivers, as well as between 74 and 84 degrees East. Many alternating grabens and horsts arose, linearly elongated in the submeridional direction (“key structure”). Trap magmatism covered almost the entire West Siberian plate (and the neighboring Tunguska syneclise). In recent decades, forecasts have been made regarding the high degree of oil and gas content of the “intermediate” floor.

Case composed of horizontally lying strata of Meso-Cenozoic sandy-clayey rocks. They have a variegated facial composition. Almost until the end of the Paleogene, marine conditions prevailed in the north; to the south they were replaced by lagoonal conditions and in the extreme south by continental ones. From the middle of the Oligocene, the continental regime spread everywhere. Sedimentation conditions changed directionally. The warm and humid climate persisted until the end of the Paleogene, and luxuriant vegetation existed. During the Neogene, the climate became noticeably cooler and drier. A huge mass of organic matter accumulated in the Jurassic and, to a lesser extent, Cretaceous strata. Organic matter dispersed in sandy-clayey material sank into the depths of the earth's crust, where it was exposed to high temperatures and petrostatic pressure, stimulating the polymerization of hydrocarbon molecules. At relatively shallow depths (up to about 2 km), long hydrocarbon chains arose, which led to the emergence of oil. At great depths, on the contrary, only gaseous hydrocarbons were formed. Therefore, the main oil fields gravitate to the southern part of the West Siberian Plate with relatively low cover thicknesses, and gas fields - to the northern regions with maximum basement depths.

Hydrocarbons dispersed in the form of an insignificant impurity slowly float to the earth's surface, most often reach the atmosphere and are destroyed. The preservation and concentration of hydrocarbons in large deposits is facilitated by the existence of reservoirs (sand and other rocks with a certain porosity) and seals (clayey, impermeable rocks).

Minerals. In the conditions of the cover of the West Siberian plate composed of sedimentary rocks, only exogenous deposits are common. Sedimentary fossils dominate, and among them are caustobiolites (oil from the southern part of the plain; the largest field is Samotlor; gas from the northern part - Urengoy in the Pur river basin, Yamburg on the Tazovsky Peninsula, Arctic on Yamal; brown coal - Kansk-Achinsk basin; peat, brown iron ore – Bakchar; evaporites of Kulunda and Baraba).

Relief. Orography and morphometry. The West Siberian Plain is considered an “ideal” low-lying plain: its absolute heights are almost everywhere below 200 m. This level is exceeded only by tiny sections of the North Sosvinskaya Upland (including the Berezovskaya Upland), the Belogorsk Continent (the right bank of the Ob River north of the mouth of the Irtysh), and the eastern section of the Siberian Uvaly ; more extensive hills are located in the foothills of Altai, the Kazakh hills, and the Urals. For a long time, on hypsometric maps, the West Siberian Plain was painted a uniform green color. A detailed study revealed, however, that the orography of the region is no less complex than within the East European Plain. Plains with heights of more than 100 m (“highlands”) and less than 100 m (lowlands) are clearly distinguished. The most famous “hills” are: Sibirskie Uvaly, Nizhneeniseiskaya, Vasyuganskaya, Barabinskaya, Kulundinskaya, (Pri) Chulymskaya; lowlands: Surgut Polesie, Kondinskaya, Severayamalskaya, Ust-Obskaya.

Morphostructure. The morphostructure of the accumulative plain clearly predominates. Only along the outskirts, especially in the southwest, south, southeast, are there denudation plains, including inclined stratal plains.

Main events of the Pleistocene. The entire territory of Western Siberia was affected to some extent glaciation on natural conditions, including morphosculpture. The ice came from the Ural-Novaya Zemlya and Taimyr-Putorana centers, which were significantly smaller than the Kola-Scandinavian center. Three glaciation epochs are most recognized: the maximum Samarova (first half of the Middle Pleistocene), Tazovsky (second half of the Middle Pleistocene), Zyryanovsky (Upper Pleistocene). Synchronously with the glacials appeared boreal transgressions, covering much larger areas than in the northeast of European Russia. At least in the northern part of Western Siberia, the glaciers were shelf glaciers and “floated”, carrying moraine material with ice. A similar picture is still observed today in the Kara Sea, which is a natural continuation of the West Siberian Plain. Land cover glaciers operated south of the Siberian Uvaly.

As now, the largest rivers flowed in accordance with the slope of the surface to the north, i.e. towards the glacier. The glacial tongue acted as a dam, to the south of which periglacial lakes (Purovskoye, Mansiyskoye, etc.) were formed, into which the melt waters of the glacier also flowed. This explains the significantly greater role of aquiglacial deposits than in Eastern Europe, and among them, outwash sands and plains.

Excessive flow of water into the periglacial lakes overwhelmed them, leading to the “splashing out” of water both to the north (which led to the formation of underwater drainage troughs, for example, the St. Anna Trench) and to the south, into the extra-glacial lakes of Western Siberia (Ishimskaya, Kulundinskaya and Barabinskaya plains). Lake and river accumulation took place here intensively. But these reservoirs also overflowed, excess water flowed through the Turgai Strait into the lakes and seas of the Black Sea-Balkhash system.

In the extreme south of Western Siberia, fine silty material was transported to the far margins of the periglacial zone mainly by flowing waters, rarely by wind. Accumulating in an arid climate, it created layers of loess-like, cover loam and loess. Thus, we can distinguish a number of zones of relict relief formation of the West Siberian Plain, successively replacing each other in a southern direction: a. boreal-marine accumulation (Yamal, territories adjacent to the Ob, Taz and Gydan bays from the south and east); b. glacial accumulation (peripheral areas of the Subpolar Urals and Putorana); V. water-glacial accumulation (mainly glacial-lacustrine - up to the parallel of the Irtysh mouth); g. terminal moraines of the Samarovo glacier (up to 59 degrees N), overlain by water-glacial deposits of the Tazovsky and Zyryanovsky glaciers; d. glacial-lacustrine accumulation; e. river and “normal” lake accumulation; and. loess formation.

Zoning of modern relief formation and types of morphosculpture. The Pleistocene relief is intensively reworked by modern agents. In the southern direction the following zones are distinguished: a. marine relief; b. cryogenic morphosculpture; V. fluvial morphosculpture, arid relief formation.

The extremely rugged coastline and low-lying flat topography of coastal areas significantly increases the area marine relief formation. The littoral zone, flooded by the sea at high tides and released at low tides, is very wide. A certain role is played by the surge of water onto flat coastal areas by the wind and the impact of the sea on the supralittoral zone, which lies above the littoral zone. Especially stand out laid down up to several kilometers wide, thermal abrasion dynamically developing shores and low but vast sea terraces.

Cryogenic The relief is widespread in the north, from the tundra to the northern subzone of the taiga inclusive. Polygonal soils, hydrolaccoliths, and heaving mounds are especially widely developed. The most significant role is played fluvial processes and forms: valley-watershed relief; in the southern regions of Western Siberia, ravines are developed in a cloak of loess-like loams and other rocks. Large ravines exist, for example, in the city limits and in the vicinity of the city of Novosibirsk. In the steppe zone it appears arid relief formation(steppe suffusion-subsidence and deflationary saucers, less often primitive accumulative sand forms).

Since relict and modern landforms overlap each other, it is necessary to identify a number of “total” geomorphological zones.

Climate The West Siberian Plain is continental (with a continentality index of 51 - 70%). It occupies a natural place in the series of increasing degrees of continentality in the eastern direction: transitional from oceanic to continental (Fennoscandia) – moderate continental (Russian Plain) – continental (Western Siberia). The most important reason for this pattern is the weakening of the climate-forming role of the Atlantic in the direction of the western transport of air masses and the gradually intensifying processes of their transformation. The essence of these processes boils down to the following: an increase in the severity of winters at almost identical summer temperatures and the resulting increase in the amplitudes of air temperature fluctuations; a decrease in precipitation and a clearer expression of the continental precipitation regime (summer maximum and winter minimum).

As in the Urals (and for the same reasons, see the corresponding section of the manual), cyclonic weather prevails in the northern part of the plain throughout the year, and anticyclonic weather prevails in the southern part. In addition, the enormous size of the territory determines the zonality of other climatic characteristics. Heat supply indicators change greatly, especially in the warm part of the year. As on the Russian Plain (see the corresponding section), there is a thickening of summer isotherms in the northern part (from 3 degrees on the Arctic coast to 16 degrees at the 64th parallel) and their thinning (up to 20 degrees at the 53rd parallel) in the southern part of the West Siberian Plain. The same can be said about the distribution of precipitation (350 mm on the coast of the Kara Sea - 500-650 mm in the middle zone - 300-250 mm in the south) and moisture (from a sharp excess - dryness indices 0.3 - in the tundra to an optimum - close to 1 in the forest-steppes - and a slight deficiency - up to 2 - in the steppe zone). In accordance with the listed patterns, the degree of continental climate of the plain increases in the southern direction.

The large extent of the plain from west to east also has an effect. The decrease in average January temperatures in this direction in the northern part of the West Siberian Plain (from –20 to –30 degrees) has already been mentioned. In the middle zone of the region, a very significant decrease in the amount of precipitation in the western part due to the influence of the barrier role of the Urals and their increase in the eastern part - in front of the barrier of the Central Siberian Plateau. In the same direction, the degree of continentality and climate severity increases.

Western Siberia exhibits typical Siberian climate features. These include, first of all, the general severity of winters or at least their individual time periods: average January temperatures are in the range of -18...-30 degrees; on the Russian Plain only the extreme northeast approaches such temperatures. A Siberian weather feature is the widespread occurrence of temperature inversions, despite the flatness of the region's topography. This is facilitated partly by the specificity of air masses overcoming the barrier of the Urals (see the corresponding section), partly by the abundance of flat orographic basins. The climate of Western Siberia is characterized by instability of weather during the transitional seasons of the year and a high probability of frost at this time.

It should be noted that there are sharp differences in the weather of the European part and Siberia. With increased cyclonic activity west of the Urals in Siberia, there is a high probability of anticyclone dominance; in summer there is a predominance of cool, rainy weather on the Russian Plain and hot, dry weather in Siberia; The mild, snowy winters of the Russian Plain correspond to the frosty, low-snow winters in Siberia. The reverse weather relationship occurs with a diametrically opposite change in the characteristics of the pressure field of the Russian Plain and Siberia.

Inland waters. Rivers, related mainly to the Kara Sea basin (basins of the Ob, Pura, Taz, Nadym, Messoyakha and a number of small rivers), are predominantly snow-fed and belong to the West Siberian type of intra-annual flow regime. It is characterized by a flood extended over time (over 2 months), but the excess of water consumption during the flood period over the annual average is small (4–5 times). The reason for this is the natural regulation of flow: excess water during floods is absorbed by very capacious floodplains and swamps. Accordingly, the summer low-water period is relatively weakly expressed, since the summer runoff is replenished from water “saved” during the flood. But the winter low-water period is characterized by very low costs, since there is only one greatly weakened power source left - groundwater. During this period, the oxygen content in rivers catastrophically decreases: it is spent on oxidation processes of organic substances contained in the water and does not penetrate well under the ice. Fish accumulate in pools, form dense mass aggregations, and are in a sleepy state.

The groundwater form a single system - the West Siberian hydrogeological basin (see its description in the general review). Their characteristics are subject to zonal distribution. In the polar and subpolar parts of the plain, groundwater lies almost on the surface, it is cold and practically does not contain mineral (gyrocarbonates, silica) impurities. In this zone, the formation of groundwater is strongly influenced by permafrost; in the northern half of Yamal and Gydan it is continuous, and to the south it is island-like. In the middle zone, as you move south, the depths, temperature and degree of mineralization of waters consistently increase. Calcium compounds appear in the solutions, then sulfates (gypsum, mirabilite), Na and K chlorides. Finally, in the extreme south of the plain, sulfates and chlorides play a leading role, so the water acquires a bitter and salty taste.

Swamps in conditions of flat, low-lying terrain, which greatly impedes the drainage of soils and soils, they become one of the leading components of landscapes. The areas of swamps and the degree of swampiness are very large (50 - 80%). Many researchers consider swamps to be aggressive PTCs, capable not only of self-preservation, but also of constant expansion at the expense of forest landscapes. This becomes possible due to the directional increase in the degree of hydromorphism of forest PTCs due to the accumulation of water (excess moisture, poor drainage) and organic matter (peat). This process is irreversible, at least in the modern era.

Zoning is observed in the distribution of bogs. Tundra swamps develop on permafrost and polygonal soils; they are frozen and contain mainly mineral substances. Within the forest-tundra and forest zone, raised oligotrophic bogs with a convex surface and a predominance of sphagnum and sedges predominate in the vegetation. In the subtaiga zone, in raised and mesotrophic transitional bogs, often hummocky, with a flat surface, green mosses and marsh grasses are mixed with sphagnum and sedges. In more southern areas, the predominance passes to lowland hummocky eutrophic bogs with a concave surface and rich vegetation.

Lakes. In the northern third of the West Siberian Plain, myriads of small thermokarst lakes (Yambuto, Neito, Yaroto, etc.) are scattered. There are very numerous small lakes of various origins in the middle zone (Piltanlor, Samotlor, Cantlor, etc.). Finally, the largest and relatively small relict lakes, often salty, are located in the south, within the Barabinskaya, Kulundinskaya, Priishimskaya and other plains (Chany, Ubinskoye, Seletyteniz, Kyzylkak, etc.). They are complemented by small saucer-shaped lakes of suffusion-subsidence genesis.

Latitudinal zonation structure. The flatness of the surface of Western Siberia determines the ideal manifestation of the latitudinal zonality of the distribution of most components of nature. However, the dominance of hydromorphic intrazonal landscapes (swamps, floodplains, riverine spaces), on the contrary, makes it difficult to identify zones.

Zonal spectrum, due to the large extent of the plain along the meridian, it is extensive: three tundra subzones, two forest-tundra subzones, northern, middle and southern taiga, sub-taiga, two forest-steppe subzones, two steppe subzones. This speaks in favor of recognition complexity of the structure zonality.

Outlines (“geometry”) of zones. In Western Siberia, the forest zone has been narrowed. Its northern border is shifted to the south, especially in comparison with Central Siberia. Usually there are two reasons for this shift - geological-geomorphological (poor drainage of the surface, which does not create conditions for the development of the root system of trees) and climatic (insufficient heat supply and sharply excessive moisture in the summer). The southern borders of the taiga and subtaiga, on the contrary, are shifted to the north under the influence of insufficient moisture for tree vegetation. The forest-steppe and steppe zones are also shifted to the north for the same reason.

Qualitative specificity of the Western Siberian provinces zones. Tundra. North of the 72nd parallel there is a subzone of arctic tundra with scanty soil and plant cover confined to frost cracks (mosses, lichens, cotton grass, partridge grass on gleyed arctic-tundra soils). Between the 72nd and 70th parallels there is a subzone of moss-lichen tundra with an admixture of wild rosemary, cranberries, blueberries and other shrubs, as well as cotton grass. The shrub tundra subzone is dominated by shrub birch, willow, and alder on tundra-gley soils. In general, the zone is called meadow-tundra; Swamps and thermokarst lakes play a significant role. Tundra fauna with ungulate and Ob lemmings is typical.

Forest-tundra stretches in a narrow (50 - 150 km) intermittent strip in the west of the plain to the south, in the east north of the Arctic Circle. Against the background of the southern tundra there are open spaces and woodlands of Siberian larch and spruce on gley-podzolic soils.

Taiga (forest-swamp zone). The predominant dark coniferous taiga consists of spruce Picea obovata, fir Abies sibirica, cedar Pinus sibirica; there is an admixture of Siberian larch Larix sibirica, and pine forests form extensive areas, especially in the western part of the plain. The degree of swampiness reaches its maximum. The soils are podzolic, often swampy and gleyed.

IN northern subzone(up to 63 - 61 degrees N in the south) forests are depressed and sparse. Mosses and sphagnum grow under their canopy; shrubs play a lesser role. Continuous permafrost is almost ubiquitous. Significant areas are occupied by swamps and meadows. Dark-coniferous and light-coniferous taiga play almost the same role. Middle taiga subzone reaches 58 - 59 degrees north latitude in the south. It is clearly dominated by dark coniferous taiga. Forests of good quality, with a developed shrub layer. Permafrost is insular. The swamps reach their maximum extent. Southern subzone It is distinguished by a more elevated and dissected relief. There is no permafrost. The southern border of the taiga approximately coincides with the 56th parallel. Spruce-fir forests dominate with a significant admixture of small-leaved species, pine and cedar. Birch forms large tracts - belniki or white taiga. In it, trees transmit more light, which favors the development of the herbaceous layer. Soddy-podzolic soils predominate. The swampiness is great, especially in Vasyugan. The southern taiga subzone extends into the Kemerovo region in two sections.

Subtaiga zone of small-leaved West Siberian forests stretches in a narrow strip from the Middle Urals to the Kemerovo region, within which it occupies the interfluve of the Yaya and Kiya rivers. Most often birch forests are identified (warty birch, downy birch, Krylova and others), less often aspen-birch forests on gray forest and soddy-podzolic soils.

Forest-steppe forms a relatively narrow strip stretching from the Southern and Middle Urals in the west to the foothills of Altai, Salair and the Chulyma River in the east; The eastern section of the zone is called the Mariinskaya forest-steppe and is located within the Kemerovo region. Woodlands (splitting trees) of warty birch or birch and aspen grow on gray forest, often solodized or podzolized soils. They alternate with meadow steppes or steppe meadows of mesophilic grasses (meadow bluegrass, reed grass, steppe timothy), rich forbs and legumes (china, clover, mouse peas) on leached and podzolized chernozems. Northern and southern subzones are distinguished with forest cover of 20–25% and 4–5%, respectively (theoretically, more or less 50%). The average plowed area of ​​the zone is 40%, pastures and hayfields occupy 30% of the total area.

Steppe the southern edge of the West Siberian Plain reaches in the east to the foothills of Altai; to the east, in the pre-Salair part of the Kemerovo region, there is a small isolated “island” of the zone, called the “steppe core” of the Kuznetsk basin. Strictly speaking, it belongs to the Altai-Sayan mountainous country, but differs little from the Western Siberian steppes. In the northern subzone, forb-grass steppes grow on ordinary chernozems. The southern subzone of feather grass-fescue (grass) steppes develops on southern low-humus chernozems and dark chestnut soils. Halophytes grow (or even dominate) on solodized soils and solonetzes. There are practically no areas of natural virgin steppes.

Physico-geographical zoning. The ideally expressed flatness of the territory makes Western Siberia a standard for the physiographic zoning of plains. In all variants of the zoning scheme of the USSR and Russia, this physical-geographical country stands out equally, which indicates the objectivity of its selection. Morphostructural (predominance of the accumulative plain), geostructural (unified geostructure of the young plate), macroclimatic (dominance of continental climate) criteria for the isolation of a physical-geographical country are understood in the same way by all authors of zoning schemes. The specificity of the structure of the latitudinal zonation of the West Siberian Plain is unique, individual and sharply contrasts with the dominance of the altitudinal zonation of neighboring mountainous countries (Urals, Kazakh small hills, Altai, Kuznetsk Alatau) and the combination of altitudinal and zonal patterns in Central Siberia.

Units second rank – physical-geographical region- are allocated according to the zonal criterion. Each region represents a segment of a complex zone within Western Siberia. The identification of such zones can be carried out with varying degrees of generalization, which leads to discrepancies in their number. This manual recommends the identification of three zones and their corresponding areas, listed in the following text.

A. The area of ​​marine and moraine plains of the tundra and forest-tundra zones.

B. The area of ​​moraine and outwash plains of the forest zone.

B. The area of ​​accumulative and denudation plains of the forest-steppe and steppe zones.

In all areas, using genetic criteria, physical geographical provinces– units third rank. The essence of the criterion is revealed in the relevant sections of the general review and when highlighting the problem of zoning the Russian Plain (see book 1 of this manual).