Central and northeastern Siberia. Eastern Siberia: climate, nature

a) The North-East of Russia is characterized by sharp orographic contrasts: medium-altitude mountain systems predominate, along with them there are plateaus, highlands and lowlands. North-Eastern Siberia is a predominantly mountainous country; lowlands occupy a little more than 20% of its area. The most important orographic elements - the marginal mountain systems of the Verkhoyansk Range and the Kolyma Highlands - form a 4000 km long arc convex to the south. Inside it are located the chains of the Chersky ridge, elongated parallel to the Verkhoyansk system, the ridges Tas-Khayakhtakh, Tas-Kystabyt (Sarycheva), Momsky, and others.

The mountains of the Verkhoyansk system are separated from the Chersky ridge by a lowered strip of the Yansky, Elginsky and Oymyakonsky plateaus. The Nera plateau and the Upper Kolyma highlands are located in the east, and in the southeast the Sette-Daban ridge and the Yudomo-Maysky highlands adjoin the Verkhoyansk ridge.

The highest mountains are located in the south of the country. Their average height is 1500-2000 m, however, in the Verkhoyansk, Tas-Kystabyt, Suntar-Khayat and Chersky ridges, many peaks rise above 2300-2800 m, and the highest of them - Mount Pobeda in the Ulakhan-Chistai ridge - reaches 3003 m.

In the northern half of the country, the mountain ranges are lower and many of them stretch in a direction close to meridional. Along with low ridges (Kharaulakhsky, Selennyakhsky), there are flat ridge-like uplands (Polousny Ridge, Ulakhan-Sis) and plateaus (Alazeysky, Yukagirsky). A wide strip of the coast of the Laptev Sea and the East Siberian Sea is occupied by the Yana-Indigirskaya lowland, from which, along the valleys of the Indigirka, Alazeya and Kolyma, the intermountain Sredneindigirskaya (Abyiskaya) and Kolyma lowlands protrude far to the south.

Thus, the North-East of Siberia is a huge amphitheater, inclined towards the Arctic Ocean;

b) The main plan of the modern relief of North-Eastern Siberia was determined by neotectonic movements. In the development of the relief of the Northeast after the Mesozoic mountain building, two periods are distinguished: the formation of widespread leveling surfaces (peneplains); and the development of intense newest tectonic processes that caused splits, deformation and displacement of ancient alignment surfaces, volcanism, violent erosion processes. At this time, the formation of the main types of morphostructures takes place: folded-block areas of ancient median massifs (Alazeya and Yukagagir plateaus, Suntar-Khayata, etc.); mountains revived by the latest arch-block uplifts and depressions of the rift zone (Moma-Selennyakh depression); folded mid-mountains of Mesozoic structures (mountains Verkhoyansk, Sette-Daban, Anyui, etc., the Yanskoye and Elga plateaus, the Oymyakon highlands); stratal-accumulative, sloping plains, created mainly by subsidence (Yano-Indigirskaya and Kolyma lowlands); fold-block ridges and plateaus on the sedimentary-volcanic complex (the Anadyr plateau, the Kolyma highlands, the ridges - Yudomsky, Dzhugdzhur, etc.);

c) The territory of the current North-Eastern Siberia in the Paleozoic and the first half of the Mesozoic was a site of the Verkhoyansk-Chukotka geosynclinal marine basin. This is evidenced by the large thickness of the Paleozoic and Mesozoic deposits, in some places reaching 20-22 thousand m, and the intense manifestation of tectonic movements that created the folded structures of the country in the second half of the Mesozoic. Especially typical are deposits of the so-called Verkhoyansk complex, whose thickness reaches 12-15 thousand m. It includes Permian, Triassic and Jurassic sandstones and shales, usually intensively dislocated and broken through by young intrusions.

The most ancient structural elements are the Kolyma and Omolon median massifs. Their base is composed of Precambrian and Paleozoic deposits, and the Jurassic suites covering them, unlike other areas, consist of weakly dislocated carbonate rocks, occurring almost horizontally; effusives also play a prominent role.

The remaining tectonic elements of the country are of younger age, predominantly Upper Jurassic (in the west) and Cretaceous (in the east). These include the Verkhoyansk folded zone and the Sette-Dabansky anticlinorium, the Yana and Indigirsko-Kolyma synclinal zones, as well as the Tas-Khayakhtakhsky and Momsky anticlinoria. The extreme northeastern regions are part of the Anyui-Chukotka anticline, which is separated from the median massifs by the Oloy tectonic depression filled with volcanic and terrigenous Jurassic deposits;

d) The main types of relief of North-Eastern Siberia form several distinct geomorphological tiers. The most important features of each of them are associated, first of all, with the hypsometric position, due to the nature and intensity of the latest tectonic movements. However, the location of the country in high latitudes and its harsh, sharply continental climate determine the altitudinal limits of the distribution of the corresponding types of mountain relief, which are different from those in more southern countries. In addition, the processes of nivation, solifluction, and frost weathering are of greater importance in their formation. The forms of permafrost relief formation also play a significant role here, and fresh traces of Quaternary glaciation are characteristic even of plateaus and areas with low mountain relief.

In accordance with morphogenetic features, the following types of relief are distinguished within the country: accumulative plains, erosion-denudation plains, plateaus, low mountains, mid-mountain and high-mountain alpine relief.

Accumulative plains occupy areas of tectonic subsidence and accumulation of loose Quaternary deposits - alluvial, lacustrine, marine and glacial. They are characterized by slightly rugged topography and slight fluctuations in relative heights. Forms that owe their origin to permafrost processes, large ice content of loose deposits and the presence of thick underground ice are widespread here: thermokarst basins, permafrost heaving mounds, frost cracks and polygons, and high ice cliffs that are intensively collapsing on sea coasts. Accumulative plains occupy vast areas of the Yana-Indigirskaya, Sredneindigirskaya and Kolyma lowlands, some islands of the seas of the Arctic Ocean (Faddeevsky, Lyakhovsky, Bunge Land, etc.). Small areas of them are also found in depressions in the mountainous part of the country (Momo-Selennyakhskaya and Seimchanskaya depressions, Yanskoye and Elga plateaus).

Erosion-denudation plains are located at the foot of some northern ridges (Anyuisky, Momsky, Kharaulakhsky, Kulara), on the peripheral sections of the Polousny ridge, the Ulakhan-Sis ridge, the Alazeysky and Yukagirsky plateaus, as well as on Kotelny Island. The height of their surface usually does not exceed 200 m, but near the slopes of some ridges it reaches 400-500 m. In contrast to the accumulative plains, these plains are composed of bedrock of various ages; the cover of loose sediments is usually thin. Therefore, rubble placers, sections of narrow valleys with rocky slopes, low hills prepared by denudation processes, as well as spots-medallions, solifluction terraces and other forms associated with the processes of permafrost relief formation are often found.

The plateau relief is most typically expressed in a wide strip separating the systems of the Verkhoyansk Range and the Chersky Range (Yanskoye, Elginskoye, Oymyakonskoye and Nerskoye plateaus). It is also characteristic of the Upper Kolyma Highlands, the Yukagir and Alazeya Plateaus, large areas of which are covered with Upper Mesozoic effusive rocks, which occur almost horizontally. However, most of the plateaus are composed of Mesozoic deposits folded into folds and represent denudation leveling surfaces, currently located at an altitude of 400 to 1200-1300 m. Upper Kolyma Highlands, where numerous granite batholiths appear in the form of high domed hills prepared by denudation. Many rivers in regions with a flat mountainous relief are mountainous in nature and flow in narrow rocky gorges.

The low mountains are occupied by areas subjected to uplifts of moderate amplitude (300-500 m) in the Quaternary. They are located mainly along the outskirts of high ridges and are dissected by a dense network of deep (up to 200-300 m) river valleys. The low mountains of North-Eastern Siberia are characterized by relief forms due to nival-solifluction and glacial processing, as well as an abundance of stony placers and rocky peaks.

The mid-mountain relief is especially characteristic of most massifs of the Verkhoyansk Range, the Yudomo-Maya Highlands, the Chersky Range, Tas-Khayakhtakh and Momsky. Significant areas are occupied by mid-mountain massifs also in the Kolyma Uplands and the Anyui Range. Modern medium-altitude mountains arose as a result of the latest uplifts of denudation plains of leveling surfaces, parts of which have been preserved here in places to this day. Then, in the Quaternary, the mountains were vigorously eroded by deep river valleys.

The height of the mid-mountain massifs is from 800-1000 to 2000-2200 m, and only at the bottom of deeply incised valleys the marks sometimes drop to 300-400 m. Relatively gentle relief forms predominate in the interfluve spaces, and fluctuations in relative heights usually do not exceed 200-300 m Forms created by Quaternary glaciers, as well as by permafrost and solifluction processes, are widespread everywhere. The development and preservation of these forms is facilitated by the harsh climate, since, unlike the more southern mountainous countries, many mid-mountain massifs of the Northeast are located above the upper limit of woody vegetation, in the mountain tundra. River valleys are quite diverse. Most often these are deep, sometimes canyon-like gorges (the depth of the Indigirka valley reaches, for example, 1500 m). However, the upper reaches of the valleys usually have a wide flat bottom and less high slopes.

The high-mountainous alpine relief is associated with areas of the most intense Quaternary uplifts located at an altitude of more than 2000-2200 m. areas of the Verkhoyansk Range. Due to the fact that the most significant role in the formation of the Alpine relief was played by the activity of Quaternary and modern glaciers, it is characterized by deep dissection and large amplitudes of heights, the predominance of narrow rocky ridges, as well as cirques, cirques and other glacial landforms;

The physical and geographical country of North-Eastern Siberia is a gigantic territory located in high-altitude latitudes and covering an area of more than one and a half million kilometers, which is limited: in the east by the channel of the Lena River, and in the west by large mountain ranges belonging to the Pacific watershed. It includes eastern Yakutia and the west of the Magadan region and is washed by the Arctic Ocean.

The extreme points of the region are: Cape St. Helena (in the far north) and the May River basin (in the south). Due to the fact that more than half of the territory that is part of this country is located beyond the Arctic Circle, it is characterized by a diverse and contrasting relief. There are plateaus, mountain ranges and flat lowlands located along the valleys of large rivers. Although this geographical country is located almost entirely on the territory of the stable Verkhoyansk-Chukotka folding, its relief continues to form.

North-Eastern Siberia is distinguished by a rather harsh climate, prone to sudden temperature changes and relatively low rainfall (one hundred to one hundred and fifty millimeters). For example: in winter, temperatures can range from minus five degrees (in November-December) to minus sixty (in January-February). Summer temperature is no exception, the temperature ranges from plus fifteen in May to plus forty in August. The depth of soil freezing in this area reaches several hundred meters. Also, North-Eastern Siberia is characterized by a distinct zoning - swampy light forests, arctic wastelands and tundra.

Despite the fact that North-Eastern Siberia is distinguished by a diverse relief, however, for the most part it is still a mountainous country, the lowlands in which occupy less than twenty percent of the area. The highest mountain ranges (average height of one and a half thousand meters and above) are located in the south of the region. Many mountain peaks of the Verkhoyansk and Chersky mountain ranges located there reach a height of two and a half thousand meters and more. The highest point in the region is Mount Pobeda, which is part of the Ulan-Chistai mountain range. It reaches a height of three thousand two hundred meters above sea level.

We owe the first mentions of the nature of this region to explorers I. Rebrov, I. Erastev and M. Stradukhin. The northern islands were discovered by A. Brunche and E. Toll, and they were studied by S. Obruchev, only in the thirties.

Geological structure of North-Eastern Siberia

This region, in the Paleozoic and Mesozoic eras, belonged to the geosynclinal marine basin. This statement is proved by the presence of Paleozoic-Mesozoic deposits located at a depth of twenty-two thousand meters. The most ancient are the Kolyma and Omolon median massifs. Younger are: western Upper Jurassic and eastern Cretaceous tectonic elements.

These include:

Sette-Dabanskaya, Tas-Khayanskaya and Momskaya atiklinoriya
Yanskaya and Indigirsko-Kolyma geological zones
Verkhoyansk zone of increased folding

By the end of the Cretaceous period, North-Eastern Siberia was a territory located on a hill in relation to neighboring regions. The temperate climate of that time and the processes of destruction of mountain ranges smoothed out the relief, forming significant flat surfaces. The folded relief in this area was formed under the influence of powerful tectonic processes characteristic of the Neogene and Quaternary period. The amplitude of these changes reached two kilometers. Particularly high mountain ranges were formed in those areas where tectonic processes were most intense.

Approximately, at the end of the Quaternary period, a powerful process of glaciation began. Due to this, large-sized valley glaciers began to form on the mountain ranges that continue to form. In the same period, the formation of permafrost begins in the coastal lowlands and the New Siberian Islands. The thickness of permafrost and intrasoil glaciation reaches fifty meters, and on the steep shores of the Arctic Ocean it exceeds sixty meters.

Valley glaciation was better expressed. On the outskirts of mountain ranges there are cirques, trough valleys and other forms of glacial exaration. In these areas, the thickness of the glaciers in some places reached three hundred meters. The Siberian mountain ranges were influenced by three independent waves of glaciation in the Middle Quaternary and Upper Quaternary geological periods.

These include:

Tobychanskoe glaciation.
Elga and Bokhapchinsky glaciers.

The first glaciation led to the appearance of coniferous trees in Siberia, including the relic Dahurian larch. The second interglacial period that followed was characterized by the predominance of mountain, taiga forests. Which, in our time, are the main representatives of wildlife in this region. The last ice age did not affect the flora and fauna of the region. During this period, the northern limit of the forest gradually shifts to the south.

The flat territories of North-Eastern Siberia are characterized by passive glaciation. A significant part of which was passive, inactive glacial formations.

Relief of the North-East of Siberia

The relief of this region is formed by several well-developed geomorphological tiers. Each stage is characterized by a unique intensity of tectonic processes and is associated with a hypsometric position. Altitudinal redistributions corresponding to the prevailing types of mountain relief explain the sharp continentality of the local climate. Also, the processes of nivation, soliflucation and frost weathering take part in its formation.

Within a given geographical country and in accordance with its morphogenetic features, the following are distinguished:

Accumulative and erosion-denudation plains;
Plateaus and low mountains;
Low-mountain and mid-mountain alpine relief.

Separate low-lying territories are occupied by weakly crossed accumulative plains, characterized by small altitudinal fluctuations. Landforms are spreading, which owe their formation to the processes of permafrost and ice cover.

Among them are:

Frost cracks and polygons;
Thermokarst basins;
Permafrost mounds;
Ice cliffs.

Accumulative plains include: Indigirskaya and Kolyma plateaus.

At the base of the Anyui, Mom, Kharaulakh and Kular mountain ranges, plains were formed that had an erosion-denudation nature. The surface of these plains has an average height of two hundred meters, and in some places reaches half a kilometer. Mountain deposits here are loose and thin.

Between the Verkhoyansk and Chersk mountain ranges there are a number of territories with a pronounced plateau relief. The largest of them are the Elga, Yanskoye, Oymyakonskoye and Nerskoye plateaus. Most of which, consists of Mesozoic rocks and have a height of up to one and a half kilometers.

The areas that were subjected to moderate uplifts in the Quaternary period are occupied by mountain lowlands, up to five hundred meters high. They occupy a position on the outskirts of the region and are dissected by a dense network of river valleys of different depths. With their typical rocky terrain.

The mid-mountain relief is typical, mainly for the Verkhoyansk mountain range, the Yudomo-Maisky upland and the Chersky, Tas-Khayansky, Momsky mountain ranges. In the Kolyma and Anyui highlands there are mid-mountain massifs, with average heights from eight hundred meters to two kilometers. They are located above the upper boundary of the plant mass, in the mountain tundra.

The mountain ridges of the highest ranges - Suntar-Khayat, Tas-Khayat and Ulan-Chistai are characterized by high-altitude alpine relief and have a height of more than two thousand meters. They are characterized by elevation changes, narrow rocky ridges, kars, circuses, etc.

The composition of Central and North-Eastern Siberia includes the entire territory of Siberia, lying to the east of the Yenisei. The Yenisei valley serves as a frontier, beyond which the structure of the subsoil, the relief, the climate, the water regime of the rivers, and the nature of the soil and vegetation cover change. In contrast to Western Siberia, elevated areas of plateaus and mountains prevail here. Therefore, the eastern part of our country is called High Siberia.

The eastern half of Russia is under the influence of the Pacific lithospheric plate, which is moving under the Eurasian continent. As a result, significant uplifts of the earth's crust took place here in the Mesozoic and Neogene-Quaternary times. Moreover, they covered the most diverse in structure and age tectonic structures - the Siberian platform with its ancient basement, the Baikalides, as well as Mesozoic folded structures of the Northeast. In the Neogene-Quaternary time, the Central Siberian Plateau was formed.

Some sections of the ancient foundation of the platform turned out to be highly elevated, for example, the Anabar Plateau and the Yenisei Ridge. Between them was the Tunguska depression of the foundation. But it also rose in modern times and the Putorana Mountains formed in its place. On the Taimyr Peninsula, the revived Byrranga mountains arose, in the North-East - rejuvenated mountains: the Verkhoyansk Range, the Chersky Mountains and the Koryak Uplands. Lowlands occupy in Central Siberia troughs between mountains and uplands (Vilyuiskaya and North Siberian) or the lowered northern edge of the Eurasian continent (Yano-Indigirskaya and Kolyma).

Uplifts of hard sections of the earth's crust were accompanied by numerous faults. The igneous masses intruded along the faults into the bowels of the platform, in some places they poured out onto the surface. The erupted magma solidified, forming lava plateaus.

Deposits of iron and copper-nickel ores and platinum are associated with outcrops of crystalline rocks of the basement. The largest coal deposits are located in tectonic troughs. Among them stands out the largest coal basin in the country - Tunguska. Coals are mined in the south of Yakutia, where the railway line from BAM is connected. Many minerals are associated with intrusions and outpourings of magmas. In sedimentary rocks, under their influence, in a number of places, coals turned into graphite. In the areas of ancient volcanism, the so-called explosion pipes were formed, to which the diamond deposits of Yakutia are confined. In the Northeast, deposits of tin ores and gold are associated with volcanic processes of past geological epochs. The sedimentary strata of the Lena-Vilyui and North Siberian lowlands contain hard and brown coal, oil and gas.

The climate of the whole of Central Siberia is sharply continental with long and very cold winters.. A significant part of the territory is located in the arctic and subarctic climatic zones. Here is the cold pole of the northern hemisphere. In winter, stable, cloudy weather with severe frosts prevails. In the intermountain basins, where heavy cold air stagnates, the average January temperature drops to -40...-50°C. But calm, dry weather helps the population endure these severe frosts. In summer, it is cloudy and the land is very hot. On the plains of central Yakutia, the average temperature in July reaches +19°C, it can rise up to +30°C and even up to +38°C. In summer, the weather is clear and hot for several weeks.

In connection with the heating of the land over Central Siberia in the summer, a reduced atmospheric pressure is established, and air rushes here from the Arctic and Pacific oceans. Along the northern coasts, the Arctic climatic front (its Pacific branch) is established, so in summer cloudy, cool weather with rains and snowfalls prevails in these areas. The abundance of moisture leads to the formation of glaciers and snowfields in the mountains. They are most widely developed in the south of the Chersky Ridge.

In most of Central Siberia, permafrost up to 1 km or more in the north has been preserved since the glacial period. In winter, ice forms on many rivers, especially in the basins of the Yana, Indigirka and Kolyma rivers, some rivers freeze to the bottom.

A number of large rivers flow through Central Siberia- Lena, tributaries of the Yenisei - Lower Tunguska, Podkamennaya Tunguska and Angara, in the northeast - the rivers Yana, Indigirka and Kolyma. All rivers originate in the mountains of the extreme south and east of the country, where relatively much precipitation falls, and carry water to the seas of the Arctic Ocean. On their way, they cross faults in the earth's crust, so their valleys often have the character of gorges with numerous rapids. Central Siberia has huge reserves of hydropower, some of which is already in use. The Irkutsk, Bratsk, and Ust-Ilim hydroelectric power plants were built on the Angara, the Vilyui hydroelectric power station operates on the Vilyui, and the Sayano-Shushenskaya hydroelectric power station operates on the Yenisei.

Most of Central Siberia is covered with light coniferous larch forests. She sheds her needles for the winter. This protects it from freezing during severe frosts. The superficial root system allows larch to grow using thawed soil layers in summer. Pine forests grow along the valleys of the Angara and Lena, where the frozen strata are covered with thick alluvial deposits. Many peaks and high parts of the slopes are occupied by rocky deserts. The northern plains are dominated by tundra and forest-tundra.

In the forests of Central Siberia, there are many fur-bearing animals, the fur of which is highly valued. In harsh climates, it becomes very lush and soft. The most common hunting animals include squirrel, sable, ermine, marten, Siberian weasel and otter.

General characteristics of North-Eastern Siberia

To the east of the lower reaches of the Lena lies a vast territory, bounded in the east by the mountain ranges of the Pacific watershed. This physical and geographical country was named North-Eastern Siberia. Including the islands of the Arctic Ocean, North-Eastern Siberia covers an area of more than $1.5 million sq. km. Within its borders is the eastern part of Yakutia and the western part of the Magadan region. North-Eastern Siberia is located in high latitudes and is washed by the waters of the Arctic Ocean and its seas.

Cape Svyatoi Nos is the northernmost point. The southern regions are in the Mai River basin. Almost half of the country's territory is located north of the Arctic Circle, which is characterized by a diverse and contrasting relief. There are mountain ranges, plateaus, flat lowlands along the valleys of large rivers. Northeastern Siberia belongs to the Verkhoyansk-Chukotka Mesozoic folding, when the main folding processes took place. The modern relief was formed as a result of the latest tectonic movements.

The climatic conditions of North-Eastern Siberia are severe, January frosts reach -$60$, -$68$ degrees. Summer temperature +$30$, +$36$ degrees. The temperature amplitude in some places is $100$-$105$ degrees, there is little precipitation, about $100$-$150$ mm. Permafrost fetters the soil to a depth of several hundred meters. On the flat territories, the distribution of soils and vegetation cover is well expressed in zonality - on the islands, the zone of arctic deserts, continental tundra and monotonous swampy larch woodlands. Altitudinal zonality is characteristic of mountainous regions.

Remark 1

Explorers I. Rebrov, I. Erastov, M. Stadukhin delivered the first information about the nature of North-Eastern Siberia. It was the middle of the $XVII$ century. The northern islands were studied by A.A. Bunge and E.V. Toll, but the information was far from complete. Only in the $30$ years of the expedition of S.V. Obruchev changed the ideas about the features of this physical and geographical country.

Despite the diversity of the relief, North-Eastern Siberia is mainly a mountainous country, lowlands occupy $20% of the area. The mountain systems of the outlying ranges of the Verkhoyansk, Chersky, Kolyma Uplands are located here. In the south of North-Eastern Siberia there are the highest mountains, the average height of which reaches $1500$-$2000$ m. whose height is $3147$ m.

Geological structure of the North-East of Siberia

In the Paleozoic era and at the beginning of the Mesozoic era, the territory of North-Eastern Siberia belonged to the Verkhoyansk-Chukotka geosynclinal marine basin. The main evidence of this is the thick Paleozoic-Mesozoic deposits, reaching $20$-$22 thousand meters in places, and strong tectonic movements, which created folded structures in the second half of the Mesozoic. The most ancient structural elements include the median massifs Kolyma and Omolon. A younger age - Upper Jurassic in the west, and Cretaceous in the east - have other tectonic elements.

These elements include:

Verkhoyansk folded zone and Sette - Dabansky atiklinorium;
Yanskaya and Indigirsko-Kolyma synclinal zones;
Tas-Khayakhtakhsky and Momsky anticlinoria.

By the end of the Cretaceous, northeastern Siberia was a territory elevated above neighboring regions. The warm climate of that time, and the denudation processes of mountain ranges leveled the relief and formed flat surfaces of leveling. The modern mountain relief was formed under the influence of tectonic uplifts in the Neogene and Quaternary period. The amplitude of these uplifts reached $1000$-$2000m. Cenozoic subsidences are occupied by lowlands and intermountain basins with strata of loose deposits.

Approximately from the middle of the Quaternary period, glaciation began, on mountain ranges that continued to rise, large valley glaciers appeared. The glaciation had an embryonic character, according to D.M. Kolosov, on the plains, firn fields formed here. The formation of permafrost begins in the second half of the Quaternary in the archipelago of the New Siberian Islands and in the coastal lowlands. The thickness of permafrost and ground ice reaches $50$-$60$ m in the cliffs of the Arctic Ocean.

Remark 2

The glaciation of the plains of northeastern Siberia was thus passive. A significant part of the glaciers were slow-moving formations that carried little loose material. The exaration impact of these glaciers had little effect on the relief.

Mountain-valley glaciation is better expressed, on the outskirts of mountain ranges there are well-preserved forms of glacial exaration - cirques, trough valleys. Valley Middle Quaternary glaciers reached a length of $200$-$300$ km. The mountains of North-Eastern Siberia, according to most experts, experienced three independent glaciations in the Middle Quaternary and Upper Quaternary.

These include:

Tobychanskoe glaciation;
Elga glaciation;
Bokhapcha glaciation.

The first glaciation led to the appearance of Siberian conifers, including Dahurian larch. During the second interglacial epoch, mountain taiga prevailed. It is typical for the southern regions of Yakutia at the present time. The last glaciation had almost no effect on the species composition of modern vegetation. The northern limit of the forest at that time, according to A.P. Vaskovsky, was noticeably shifted to the south.

The relief of the North-East of Siberia

The relief of North-Eastern Siberia forms several well-defined geomorphological tiers. Each stage is associated with a hypsometric position, which was determined by the nature and intensity of the latest tectonic movements. The position in high latitudes and the sharp continentality of the climate cause different altitudinal limits of the distribution of the corresponding types of mountainous relief. In its formation, the processes of nivation, solifluction, and frost weathering are of greater importance.

Within North-Eastern Siberia, in accordance with morphogenetic features, the following are distinguished:

Accumulative plains;
Erosion-denudation plains;
Plateau;
low mountains;
Mid-mountain and low-mountain alpine relief.

Separate areas of tectonic subsidence occupy accumulative plains, characterized by a slightly rugged relief and small fluctuations in relative height. Such forms are spreading, which owe their formation to permafrost processes, large ice content of loose deposits and thick underground ice.

Among them are:

Thermokarst basins;
Permafrost heaving mounds;
Frost cracks and polygons;
High ice cliffs on the sea coasts.

The accumulative plains include the Yano-Indigirskaya, Sredne-Indigirskaya, and Kolyma lowlands.

At the foot of a number of ridges - Anyuisky, Momsky, Kharaulakhsky, Kulara - formed erosion-denudation plains. The surface of the plains has a height of no more than $200$ m, but can reach $400$-$500$ m near the slopes of a number of ridges. Loose deposits here are thin and they are composed mainly of bedrock of different ages. As a result, gravel placers, narrow valleys with rocky slopes, low hills, spots-medallions, and solifluction terraces can be found here.

Between the Verkhoyansky ridge and the Chersky ridge there is a pronounced plateau terrain- Yanskoye, Elginskoye, Oymyakonskoye, Nerskoye plateaus. Most of the plateaus are composed of Mesozoic deposits. Their modern height is from $400$ to $1300$ m.

Those areas that were subjected to uplifts of moderate amplitude in the Quaternary are occupied low mountains, with a height of $300$-$500$ m. They occupy a marginal position and are dissected by a dense network of deep river valleys. Typical landforms for them are an abundance of stony placers and rocky peaks.

Middle mountain relief is mainly characteristic of most of the massifs of the Verkhoyansk Range system. Yudomo-May Highland, Chersky Ridge, Tas-Khayakhtakh, Momsky. In the Kolyma Highlands and the Anyui Range, there are also mid-mountain massifs. Their height is from $800$-$2200$ m. The mid-mountain massifs of North-Eastern Siberia are located in the mountain tundra, above the upper limit of woody vegetation.

High Alpine relief. These are the crests of the highest mountain ranges - Suntar-Khayata, Ulakhan-Chistai, Tas-Khayakhtakh, etc. They are associated with the areas of the most intense uplifts of the Quaternary period. The height is more than $2000$-$2200$ m. The activity of Quaternary and modern glaciers plays a significant role in the formation of the Alpine relief, therefore large amplitudes of heights, deep dissection, narrow rocky ridges, cirques, cirques and other glacial landforms will be characteristic.

Eastern Siberia is part of the Asian territory of the Russian Federation. It is located from the borders of the Pacific Ocean to the Yenisei River. This zone is characterized by an extremely harsh climate and limited fauna and flora.

Geographic Description

Eastern and occupy almost two-thirds of the territory of Russia. They are located on the plateau. The eastern zone covers an area of about 7.2 million square meters. km. Its possessions extend up to the Sayan mountain ranges. Most of the territory is represented by the tundra lowland. The mountains of Transbaikalia play a significant role in the formation of the relief.

Despite the harsh climatic conditions, there are quite a lot of large cities in Eastern Siberia. The most attractive from an economic point of view are Norilsk, Irkutsk, Chita, Achinsk, Yakutsk, Ulan-Ude, and others. Within the zone are the Zabaikalsky and Krasnoyarsk Territories, the republics of Yakutia, Buryatia, Tuva and other administrative regions.

The main type of vegetation is the taiga. It will be washed from Mongolia to the borders of the forest-tundra. Occupies over 5 million sq. km. Most of the taiga is represented by coniferous forests, which make up 70% of the local vegetation. Soils develop unevenly relative to natural zones. In the taiga zone, the soil is favorable, stable, in the tundra - rocky, frozen.

Within the interfluve and lowlands, insignificant swamps are observed. However, they are much less than in the same Western Siberia. But in the eastern region, arctic deserts and deciduous plantations are often found.

Terrain characteristics

Eastern Siberia of Russia is located at a high level above the sea. All the fault of the plateau, which is located in the middle part of the zone. Here the height of the platform varies from 500 to 700 meters above sea level. The relative averageness of the region is noted. The highest points are the interfluve of the Lena and the Vilyui plateau - up to 1700 meters.

The base of the Siberian platform is represented by a crystalline folded basement, on which there are huge sedimentary layers up to 12 kilometers thick. The north of the zone is determined by the Aldan shield and the Anabar massif. The average thickness of the soil is about 30 kilometers.

To date, the Siberian platform contains several main types of rocks. These are marble, and schist, and charnockite, etc. The oldest deposits date back to 4 billion years. Igneous rocks were formed as a result of eruptions. Most of these deposits are located in and also in the Tunguska depression.

The modern relief is a combination of lowlands and uplands. Rivers flow in the valleys, swamps form, coniferous trees grow better on the hills.

Features of the water area

It is generally accepted that the Far East faces the Arctic Ocean with its "facade". The eastern region borders on such seas as the Kara, Siberian and Laptev. Of the largest lakes, it is worth highlighting Baikal, Lama, Taimyr, Pyasino and Khantayskoye.

Rivers flow in deep valleys. The most significant of them are the Yenisei, Vilyui, Lena, Angara, Selenga, Kolyma, Olekma, Indigirka, Aldan, Lower Tunguska, Vitim, Yana and Khatanga. The total length of the rivers is about 1 million km. Most of the inland basin of the region belongs to the Arctic Ocean. Other external water areas include such rivers as Ingoda, Argun, Shilka and Onon.

The main source of nutrition for the inner basin of Eastern Siberia is the snow cover, which melts in large volumes under the influence of sunlight from the beginning of summer. The next most important role in the formation of the continental water area is played by rains and groundwater. The highest level of the basin's runoff is observed in the summer.

The largest and most important river in the region is the Kolyma. Its water area occupies more than 640 thousand square meters. km. The length is about 2.1 thousand km. The river originates in the Upper Kolyma Highlands. Water consumption exceeds 120 cubic meters per year. km.

Eastern Siberia: climate

The formation of meteorological features of the region is determined by its territorial location. The climate of Eastern Siberia can be briefly described as continental, consistently severe. There are significant seasonal fluctuations in cloudiness, temperature, and precipitation levels. The Asian anticyclone forms vast areas of high pressure in the region, especially this phenomenon occurs in winter. On the other hand, severe frost makes air circulation changeable. Because of this, temperature fluctuations at different times of the day are more significant than in the west.

The climate of North-Eastern Siberia is represented by changeable air masses. It is characterized by increased precipitation and dense snow cover. This area is dominated by continental flows, which are rapidly cooling in the ground layer. That is why in January the temperature drops to a minimum. Arctic winds prevail at this time of the year. Often in winter, you can observe air temperatures down to -60 degrees. Basically, such minima are inherent in depressions and valleys. On the plateau, the indicators do not drop below -38 degrees.

Warming is observed with the arrival of air flows from China and Central Asia to the region.

winter time

No wonder it is believed that Eastern Siberia has the heaviest and most severe. The table of temperature indicators in winter is proof of this (see below). These indicators are presented as average values for the last 5 years.

Due to the increased dryness of the air, the constancy of the weather and the abundance of sunny days, such low rates are easier to tolerate than in a humid climate. One of the defining meteorological characteristics of winter in Eastern Siberia is the absence of wind. Most of the season there is a moderate calm, so there are practically no blizzards and snowstorms here.

Interestingly, in the middle part of Russia, a frost of -15 degrees is felt much stronger than in Siberia -35 C. Nevertheless, such low temperatures significantly worsen the living conditions and activities of local residents. All living quarters have thickened walls. Expensive fuel boilers are used to heat buildings. The weather begins to improve only with the onset of March.

warm seasons

In fact, spring in this region is short, as it comes late. The eastern one, which changes only with the arrival of warm Asian air currents, begins to wake up only by mid-April. It is then that the stability of positive temperatures during the daytime is noted. Warming comes in March, but it is insignificant. By the end of April, the weather begins to change for the better. In May, the snow cover completely melts, the vegetation blooms.

In summer, the weather becomes relatively hot in the south of the region. This is especially true for the steppe zone of Tuva, Khakassia and Transbaikalia. In July, the temperature here rises to +25 degrees. The highest rates are observed on flat terrain. It is still cool in the valleys and highlands. If we take the whole of Eastern Siberia, then the average summer temperature here is from +12 to +18 degrees.

Climate features in autumn

Already at the end of August, the first frosts begin to envelop the Far East. They are observed mainly in the northern part of the region at night. During the day the bright sun shines, it rains with sleet, sometimes the wind intensifies. It is worth noting that the transition to winter is much faster than from spring to summer. In the taiga, this period takes about 50 days, and in the steppe area - up to 2.5 months. All these are characteristic features that distinguish Eastern Siberia from other northern zones.

The climate in autumn is also represented by an abundance of rains coming from the west. Moist Pacific winds blow most often from the east.

Precipitation level

Relief is responsible for atmospheric circulation in Eastern Siberia. Both the pressure and the speed of air mass flows depend on it. About 700 mm of precipitation falls annually in the region. The maximum indicator for the reporting period is 1000 mm, the minimum is 130 mm. The level of precipitation is not clearly defined.

On the plateau in the middle lane, it rains more often. Due to this, the amount of precipitation sometimes exceeds the mark of 1000 mm. The most arid region is Yakutsk. Here the amount of precipitation varies within 200 mm. The least rain falls between February and March - up to 20 mm. The western regions of Transbaikalia are considered the optimal zones for vegetation with respect to precipitation.

Permafrost

Today there is no place in the world that could compete in terms of continentality and meteorological anomalies with a region called Eastern Siberia. The climate in some areas is striking in its severity. In the immediate vicinity of the Arctic Circle lies the permafrost zone.

This area is characterized by low snow cover and low temperatures throughout the year. Because of this, mountain weather and the ground lose a huge amount of heat, freezing to whole meters in depth. The soils here are predominantly stony. Groundwater is underdeveloped and often freezes for decades.

Vegetation of the region

The nature of Eastern Siberia is mostly represented by taiga. Such vegetation extends for hundreds of kilometers from the Lena River to the Kolyma. In the south, the taiga borders on the local possessions are untouched by man. Nevertheless, due to the arid climate, the threat of large-scale fires always hangs over them. In winter, the temperature in the taiga drops to -40 degrees, but in summer the figures often rise to +20. Rainfall is moderate.

Also, the nature of Eastern Siberia is represented by the tundra zone. This zone is adjacent to the Arctic Ocean. The soils here are bare, the temperature is low, and the humidity is excessive. Flowers such as cotton grass, gravel, poppy, saxifrage grow in mountainous areas. From the trees of the region, one can distinguish spruces, willows, poplars, birches, pines.

Animal world

Almost all regions of Eastern Siberia are not rich in fauna. The reasons for this are permafrost, lack of food and underdevelopment of deciduous flora.

The largest animals are the brown bear, lynx, elk and wolverine. Sometimes you can meet foxes, ferrets, stoats, badgers and weasels. Musk deer, sable, deer and bighorn sheep live in the central strip.

Because of the eternally frozen soil, only a few species of rodents are found here: squirrels, chipmunks, flying squirrels, beavers, marmots, etc. But the feathered world is extremely diverse: capercaillie, crossbill, hazel grouse, goose, crow, woodpecker, duck, nutcracker, sandpiper, etc. .