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 slightly more than 20% of its area. The most important orographic elements - the marginal mountain systems of the Verkhoyansk Range and the Kolyma Plateau - form a convex arc to the south, 4000 km long. Inside it are located the chains of the Chersky ridge, Tas-Khayakhtakh, Tas-Kystabyt (Sarycheva), Momsky and others, stretched parallel to the Verkhoyansk system.

The mountains of the Verkhoyansk system are separated from the Chersky ridge by a low strip of the Yana, Elga and Oymyakon plateaus. In the east are the Nerskoye Plateau and the Upper Kolyma Highlands, and in the southeast the Sette-Daban ridge and the Yudomo-Mayskoye Highlands adjoin the Verkhoyansk Range.

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

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

Thus, Northeast Siberia is a huge amphitheater inclined towards the Arctic Ocean;

b) The basic 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 planation surfaces (peneplains); and the development of intense new tectonic processes that caused splits, deformation and movement of ancient planation surfaces, volcanism, and violent erosion processes. At this time, the formation of the main types of morphostructures took place: folded-block areas of the ancient middle massifs (Alazeya and Yukagagir plateaus, Suntar-Khayata, etc.); mountains, revived by the latest arch-block uplifts, and depressions of the rift zone (Mom-Selennyakh depression); folded middle mountains of Mesozoic structures (Verkhoyansk, Sette-Daban, Anyui mountains, etc., Yanskoye and Elga plateaus, Oymyakon highlands); stratified-accumulative, sloping plains created mainly by subsidence (Yana-Indigirka and Kolyma lowlands); folded-block ridges and plateaus on the sedimentary-volcanic complex (Anadyr Plateau, Kolyma Highlands, ridges - Yudomsky, Dzhugdzhur, etc.);

c) The territory of present-day North-Eastern Siberia in the Paleozoic and the first half of the Mesozoic was a section of the Verkhoyansk-Chukchi geosynclinal sea basin. This is evidenced by the large thickness of Paleozoic and Mesozoic sediments, in some places reaching 20-22 thousand m, and the intense manifestation of tectonic movements that created folded structures in the country in the second half of the Mesozoic. Particularly typical are the deposits of the so-called Verkhoyansk complex, the thickness of which reaches 12-15 thousand m. It includes Permian, Triassic and Jurassic sandstones and shales, usually intensively dislocated and intruded by young intrusions.

The most ancient structural elements are the Kolyma and Omolon middle massifs. Their base is composed of Precambrian and Paleozoic sediments, and the Jurassic formations covering them, unlike other areas, consist of weakly dislocated carbonate rocks lying 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-Daban anticlinorium, the Yansk and Indigirka-Kolyma synclinal zones, as well as the Tas-Khayakhtakh and Mom anticlinoriums. The extreme northeastern regions are part of the Anyui-Chukotka anticline, which is separated from the middle massifs by the Oloi tectonic depression, filled with volcanogenic and terrigenous Jurassic deposits;

d) The main types of relief of North-Eastern Siberia form several clearly defined geomorphological stages. The most important features of each of them are associated, first of all, with the hypsometric position, determined by the nature and intensity of recent tectonic movements. However, the country's location in high latitudes and its harsh, sharply continental climate determine the altitudinal limits of distribution of the corresponding types of mountainous relief that are different from those in more southern countries. In addition, the processes of nivation, solifluction and frost weathering become more important in their formation. 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 the morphogenetic characteristics within the country, the following types of relief are distinguished: 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 sediments - alluvial, lacustrine, marine and glacial. They are characterized by slightly rugged terrain and slight fluctuations in relative heights. Forms that owe their origin to permafrost processes, high ice content of loose sediments and the presence of thick underground ice are widespread here: thermokarst basins, frozen heaving mounds, frost-breaking cracks and polygons, and on the sea coasts intensively collapsing high ice cliffs. Accumulative plains occupy vast areas of the Yana-Indigirsk, Middle Indigirsk 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 the depressions of the mountainous part of the country (Momo-Selennyakh and Seymchan basins, Yanskoye and Elga plateaus).

Erosion-denudation plains are located at the foot of some northern ridges (Anyuysky, Momsky, Kharaulakhsky, Kular), 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. Unlike accumulative plains, these plains are composed of bedrock of various ages; the cover of loose sediments is usually thin. Therefore, there are often gravelly placers, areas of narrow valleys with rocky slopes, low hills prepared by denudation processes, as well as medallion spots, solifluction terraces and other forms associated with the processes of permafrost relief formation.

The flat-mountain relief is most typically expressed in a wide strip separating the systems of the Verkhoyansk ridge and the Chersky ridge (Yanskoye, Elga, Oymyakon and Nerskoye plateaus). It is also characteristic of the Upper Kolyma Highlands, the Yukagir and Alazeya plateaus, significant areas of which are covered with Upper Mesozoic effusives, lying almost horizontally. However, most of the plateaus are composed of folded Mesozoic sediments and represent denudation leveling surfaces, currently located at an altitude of 400 to 1200-1300 m. In places, higher remnant massifs rise above their surface, typical, for example, of the upper reaches of the Adycha and especially The Upper Kolyma Highlands, where numerous granite batholiths appear in the form of high dome-shaped hills prepared by denudation. Many rivers in areas with flat mountain topography are mountainous in nature and flow through narrow rocky gorges.

Low mountains are occupied by areas that were subject to uplifts of moderate amplitude (300-500 m) in the Quaternary. They are located mainly on 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 typical relief forms caused by nival-solifluction and glacial processing, as well as an abundance of rocky placers and rocky peaks.

Mid-mountain relief is especially characteristic of most of the massifs of the Verkhoyansk ridge system, the Yudomo-Maisky highlands, the Chersky ridge, Tas-Khayakhtakh and Momsky. Significant areas are occupied by mid-mountain massifs also in the Kolyma Highlands and the Anyui Range. Modern mid-altitude mountains arose as a result of recent uplifts of denudation plains of planation surfaces, sections of which in some places have been preserved here to this day. Then, in Quaternary times, the mountains were subjected to vigorous erosion by deep river valleys.

The height of mid-mountain massifs ranges from 800-1000 to 2000-2200 m, and only at the bottom of deeply incised valleys do the elevations sometimes drop to 300-400 m. In the interfluve spaces, relatively flat landforms predominate, and fluctuations in relative heights usually do not exceed 200-300 m Forms created by Quaternary glaciers, as well as permafrost and solifluction processes, are widespread throughout. The development and preservation of these forms is facilitated by the harsh climate, since, unlike more southern mountainous countries, many mid-mountain massifs of the Northeast are located above the upper limit of tree vegetation, in a strip of 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, upper valleys usually have wide, flat bottoms and shallower slopes.

The high alpine relief is associated with areas of the most intense Quaternary uplifts, located at an altitude of more than 2000-2200 m. These include the crests of the highest ridges (Suntar-Khayata, Tas-Khayakhtakh, Chersky Tas-Kystabyt ridge. Ulakhan-Chistai), as well as the central 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-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 bed of the Lena River, and in the west by large mountain ranges belonging to the Pacific watershed. It includes eastern Yakutia and western Magadan region and is washed by the Arctic Ocean.

The extreme points of the region are: Cape St. Helens (in the far north) and the May River basin (in the south). Due to the fact that more than half of the territory that makes up this country is located beyond the Arctic Circle, it is characterized by a varied and contrasting topography. 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-Chukchi fold, its relief continues to form.

North-Eastern Siberia is characterized by a rather harsh climate, prone to sudden temperature changes and relatively low precipitation (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 temperatures are no exception; temperatures range 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 clearly defined zonation - swampy woodlands, arctic wastelands and tundras.

Despite the fact that North-Eastern Siberia has a varied topography, for the most part it is still a mountainous country, the lowlands of 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 located there in the Verkhoyansk and Chersky mountain ranges reach a height of two and a half thousand meters and higher. The highest point in the region is Mount Pobeda, part of the Ulan-Chistai mountain range. It reaches a height of three thousand two hundred meters above sea level.

We owe the first mention of the nature of this region to the 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 a geosynclinal sea basin. This statement is proven by the presence of Paleozoic-Mesozoic deposits located at a depth of twenty-two thousand meters. The Kolyma and Omolon middle massifs are considered the most ancient. Younger are: western Upper Jurassic and eastern Cretaceous tectonic elements.

These include:

Sette-Dabanskaya, Tas-Khayanskaya and Momskaya aticlinoria
Yana and Indigirka-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 periods. The amplitude of these changes reached two kilometers. Especially high mountain ranges were formed in those areas where tectonic processes were most intense.

Around the end of the Quaternary period, a powerful process of glaciation began. Thanks to this, large-sized valley glaciers began to form on the mountain ranges that continued 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 exceeds sixty meters.

Valley glaciation was more pronounced. On the outskirts of mountain ranges there are cirques, trough valleys and other forms of glacial gouging. In these areas, the thickness of 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:

Tobychan glaciation.
Elginsky and Bokhapchinsky glaciers.

The first glaciation led to the appearance of coniferous trees in Siberia, including the relict Daurian larch. The second interglacial period that followed was characterized by the predominance of mountain and 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, slow-moving glacial formations.

Relief of North-East Siberia

The relief of this region is formed by several well-developed geomorphological stages. Each stage is characterized by a unique intensity of tectonic processes and is associated with a hypsometric position. The altitudinal ranges corresponding to the prevailing types of mountainous relief explain the sharp continental nature of the local climate. Also, the processes of nivation, solifluction and frost weathering take part in its formation.

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

Accumulative and Erosion-denudation plains;
Highlands and lowlands;
Low-mountain and mid-mountain alpine terrain.

Some lowland areas are occupied by weakly rugged accumulative plains, characterized by slight altitudinal fluctuations. Landforms are spreading, which owe their formation to the processes of permafrost and ice content.

Among them are:

Frost cracks and polygons;
Thermokarst basins;
Permafrost mounds;
Icy sea cliffs.

Accumulative plains include: the Indigirka and Kolyma plateaus.

At the base of the Anyuisky, Momsky, Kharaulakhsky and Kularsky mountain ranges, plains of erosion-denudation nature were formed. The surface of these plains has an average height of two hundred meters, and in some places reaches half a kilometer. The rock deposits here are loose and thin.

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

Areas that in the Quaternary period were subject to uplifts of moderate amplitude 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 varying depths. With typical rocky terrain.

Mid-mountain relief is typical mainly for the Verkhoyansk mountain range, the Yudomo-Maysky highlands 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 border of the vegetation massif, in a strip of mountain tundra.

The mountain ridges of the highest ranges - Suntar-Hayat, Tas-Hayat and Ulan-Chistai - are characterized by high-altitude alpine terrain and have heights of more than two thousand meters. They are characterized by elevation changes, narrow rocky ridges, punishments, circuses, etc.

Central and North-Eastern Siberia includes the entire territory of Siberia lying east of the Yenisei. The Yenisei Valley serves as a boundary beyond which the structure of the subsoil, relief, climate, water regime of rivers, and the nature of soil and vegetation change. Unlike Western Siberia, elevated areas of plateaus and mountains predominate 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 occurred here in the Mesozoic and Neogene-Quaternary times. Moreover, they covered the most diverse tectonic structures in structure and age - the Siberian Platform with its ancient foundation, the Baikalids, as well as folded Mesozoic structures of the Northeast. In the Neogene-Quaternary, the Central Siberian Plateau was formed.

Some areas 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 in modern times it also rose and in its place the Putorana Mountains formed. On the Taimyr Peninsula, the revived Byrranga Mountains arose, in the North-East - rejuvenated mountains: the Verkhoyansk Range, the Chersky Mountains and the Koryak Highlands. In Central Siberia, lowlands occupy troughs between mountains and hills (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. Along faults, magmatic masses penetrated into the depths of the platform, and 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 basement rocks. The largest coal deposits are located in tectonic troughs. Among them, the country's largest coal basin, the Tunguska, stands out. 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 areas of ancient volcanism, 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 eras. The sedimentary strata of the Leno-Vilyui and North Siberian lowlands contain hard and brown coal, oil and gas.

The climate of all 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. The cold pole of the northern hemisphere is located here. In winter, stable, partly cloudy weather with severe frosts prevails. In intermountain basins, where heavy cold air stagnates, the average January temperature drops to -40...-50°C. But windless, dry weather helps the population endure these severe frosts. In summer there are few clouds and the land gets very hot. On the plains of central Yakutia, the average July temperature reaches +19°C, and can rise to +30°C and even +38°C. In summer the weather is clear and hot for several weeks.

Due to the heating of the land over Central Siberia in the summer, low atmospheric pressure is established, and air from the Arctic and Pacific oceans rushes here. The Arctic climate front (its Pacific branch) is established along the northern coasts, so in the summer cloudy, cool weather with rain and snowfall 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 glacial times. 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 Yana, Indigirka and Kolyma rivers. 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 hydroelectric power, some of which is already in use. The Irkutsk, Bratsk, and Ust-Ilimsk hydroelectric power stations were built on the Angara, the Vilyuiskaya hydroelectric power station operates on the Vilyui, and the Sayano-Shushenskaya hydroelectric power station on the Yenisei.

Most of Central Siberia is covered with light coniferous forests consisting of larch. For the winter it sheds its needles. This protects it from freezing during severe frosts. The superficial root system allows larch to grow using thawed layers of soil in the summer. Along the valleys of the Angara and Lena, where the frozen strata are covered with thick alluvial deposits, pine forests grow. The lower parts of the mountain slopes are covered with larch forests, which in the upper parts are replaced by dwarf cedar and mountain tundra. Many peaks and high parts of the slopes are occupied by rocky deserts. The northern plains are dominated by tundra and forest-tundra.

The forests of Central Siberia are home to many fur-bearing animals, whose fur is highly valued. In harsh climates it becomes very lush and soft. The most common game animals include squirrel, sable, ermine, marten, weasel and otter.

General characteristics of North-Eastern Siberia

To the east of the lower reaches of the Lena lies a vast territory, bounded on the east by the mountain ranges of the Pacific watershed. This physical-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 are 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 Svyatoy Nos is the extreme northern point. The southern regions are located in the Mai River basin. Almost half of the country’s territory is located north of the Arctic Circle, which is characterized by varied and contrasting topography. There are mountain ranges, plateaus, and flat lowlands along the valleys of large rivers. North-Eastern Siberia belongs to the Verkhoyansk-Chukchi Mesozoic folding, when the main folding processes took place. The modern relief was formed as a result of recent tectonic movements.

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

Note 1

Explorers I. Rebrov, I. Erastov, M. Stadukhin brought the first information about the nature of North-Eastern Siberia. It was the middle of the 17th 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 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. Here are located the mountain systems of the outlying ridges of the Verkhoyansk, Chersky, and Kolyma Highlands. In the south of North-Eastern Siberia there are the highest mountains, the average height of which reaches $1500$-$2000$ m. Many peaks of the Verkhoyansk ridge and the Chersky ridge rise above $2300$-$2800$ m. The peak is located in the Ulakhan-Chistai ridge - this is Mount Pobeda, whose height is $3147$ m.

Geological structure of North-East 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 sea 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 middle Kolyma and Omolon massifs. The remaining tectonic elements have a younger age - Upper Jurassic in the west, and Cretaceous in the east.

These elements include:

Verkhoyansk folded zone and Sette – Daban atiklinorium;
Yana and Indigirka-Kolyma synclinal zones;
Tas-Khayakhtakh and Momsky anticlinoriums.

By the end of the Cretaceous period, North-Eastern Siberia was a territory elevated above neighboring regions. The warm climate of this time and the denudation processes of mountain ranges leveled the relief and formed flat leveling surfaces. The modern mountainous relief was formed under the influence of tectonic uplifts in the Neogene and Quaternary periods. The amplitude of these uplifts reached $1000$-$2000$ m. Particularly high ridges rose in those areas where the uplifts were most intense. Cenozoic depressions are occupied by lowlands and intermountain basins with layers of loose sediments.

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

Note 2

The glaciation of the plains of North-Eastern Siberia was thus passive. A significant part of the glaciers were inactive formations that carried little loose material. The exaration effect 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 gouging - cirques, trough valleys. Mid-Quaternary valley 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 times.

These include:

Tobychan glaciation;
Elga glaciation;
Bokhapcha glaciation.

The first glaciation led to the appearance of Siberian conifers, including Daurian larch. During the second interglacial era, mountain taiga was dominant. It is typical for the southern regions of Yakutia at present. 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.

Relief of North-East Siberia

The relief of North-Eastern Siberia forms several well-defined geomorphological stages. Each tier is associated with a hypsometric position, which was determined by the nature and intensity of recent tectonic movements. The position in high latitudes and the sharp continentality of the climate determine other altitudinal limits for the distribution of the corresponding types of mountainous relief. In its formation, the processes of nivation, solifluction, and frost weathering become more important.

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

Accumulative plains;
Erosion-denudation plains;
Plateau;
Lowlands;
Mid-mountain and low-mountain alpine terrain.

Certain areas of tectonic subsidence occupy accumulative plains, characterized by slightly rugged terrain and slight fluctuations in relative height. Such forms are widespread that owe their formation to permafrost processes, high ice content of loose sediments and thick underground ice.

Among them are:

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

Accumulative plains include the Yana-Indigirskaya, Sredne-Indigirskaya, and Kolyma lowlands.

At the foot of a number of ridges - Anyuisky, Momsky, Kharaulakhsky, Kular - formed erosion-denudation plains. The surface of the plains has a height of no more than $200$ m, but can reach $400$-$500$ m on the slopes of a number of ridges. The loose sediments here are thin and are composed mainly of bedrock of different ages. As a result, here you can find gravelly placers, narrow valleys with rocky slopes, low hills, medallion spots, and solifluction terraces.

Between the Verkhoyansk 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 subject 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 rocky placers and rocky peaks.

Mid-mountain terrain mainly characteristic of most of the massifs of the Verkhoyansk Range system. Yudomo-Maysky upland, Chersky ridge, Tas-Khayakhtakh, Momsky. There are also mid-mountain massifs in the Kolyma Highlands and Anyui Range. Their height ranges from $800$-$2200$ m. The mid-mountain massifs of North-Eastern Siberia are located in a strip of mountain tundra, above the upper limit of tree vegetation.

High alpine terrain. These are the ridges 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. In the formation of the alpine relief, a significant role is played by the activity of Quaternary and modern glaciers, therefore large amplitudes of heights, deep dissection, narrow rocky ridges, cirques, cirques and other glacial forms of relief 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.

Geographical description

Eastern and occupy almost two-thirds of the territory of Russia. Situated on a plateau. The eastern zone covers an area of about 7.2 million square meters. km. Her possessions extend all the way to the Sayan mountain ranges. Most of the territory is represented by 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 few large cities in Eastern Siberia. The most attractive from an economic point of view are Norilsk, Irkutsk, Chita, Achinsk, Yakutsk, Ulan-Ude, etc. Within the zone are the Trans-Baikal and Krasnoyarsk territories, the republics of Yakutia, Buryatia, Tuva and other administrative regions.

The main type of vegetation is taiga. It stretches from Mongolia to the borders of the forest-tundra. Occupies more than 5 million square meters. 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 and stable, in the tundra it is rocky and frozen.

Within the interfluve and lowlands, minor swamps are observed. However, there are much fewer of them than in Western Siberia. But in the eastern region there are often arctic deserts and deciduous plantations.

Relief characteristics

Eastern Siberia of Russia is located at a high level above the sea. The plateau, which is located in the middle part of the zone, is to blame. Here the height of the platform varies from 500 to 700 meters above sea level. The relative averaging of the region is noted. The highest points are considered to be 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.

Today, the Siberian platform contains several main types of rocks. This includes marble, crystalline slate, charnockite, etc. The oldest deposits date back to 4 billion years. Igneous rocks are formed as a result of eruptions. Most of these deposits are found in the Tunguska depression.

The modern relief is a combination of lowlands and hills. Rivers flow in the valleys, swamps form, and 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 “façade”. The eastern region borders on the Kara, Siberian and Laptev seas. 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 region's inland basin belongs to the Arctic Ocean. Other external water areas include rivers such as Ingoda, Argun, Shilka and Onon.

The main source of nutrition for the inland basin of Eastern Siberia is the snow cover, which melts in large quantities under the influence of sunlight from the beginning of summer. The next most important role in the formation of continental waters is played by rain and groundwater. The highest level of basin flow is observed in 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. The annual water consumption exceeds 120 cubic meters. km.

Eastern Siberia: climate

The formation of meteorological features of a region is determined by its territorial location. The climate of Eastern Siberia can be briefly described as continental, consistently harsh. There are significant seasonal fluctuations in cloudiness, temperature, and precipitation levels. The Asian anticyclone forms vast areas of high pressure in the region, this phenomenon is especially common 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 variable air masses. It is characterized by increased precipitation and dense snow cover. This area is dominated by continental flows, which rapidly cool in the surface layer. That is why in January the temperature drops to a minimum. Arctic winds predominate at this time of year. Often in winter you can observe air temperatures down to -60 degrees. Basically, such minimums are characteristic of basins 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 into the region.

winter time

It is not for nothing that it is believed that Eastern Siberia has the heaviest and most severe conditions. The table of temperature indicators in winter is proof of this (see below). These indicators are presented as average values over 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 levels are more easily tolerated 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 moderate calm, so there are practically no blizzards or blizzards here.

It is interesting that in the central 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 areas 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 arrives 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 begins 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 and the vegetation blooms.

In the summer in the south of the region the weather becomes relatively hot. 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, there are rains with sleet, and sometimes the wind increases. It is worth noting that the transition to winter occurs 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 rain coming from the west. Humid Pacific winds most often blow from the east.

Precipitation level

The relief is responsible for atmospheric circulation in Eastern Siberia. Both the pressure and the speed of air mass flow depend on it. The region receives about 700 mm of precipitation annually. 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 zone it rains more often. Due to this, the amount of precipitation sometimes exceeds 1000 mm. The most arid region is considered to be Yakutia. Here the amount of precipitation varies within 200 mm. The least amount of rain falls between February and March - up to 20 mm. The western regions of Transbaikalia are considered optimal zones for vegetation relative to precipitation.

Permafrost

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

This area is characterized by light snow cover and low temperatures throughout the year. Because of this, mountain weather and soil lose a huge amount of heat, freezing to depths of meters. The soils here are predominantly rocky. Groundwater is poorly developed 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 Kolyma. In the south, the taiga borders on the local property, untouched by man. However, 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 readings often rise to +20. Precipitation is moderate.

The nature of Eastern Siberia is also 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. In mountainous areas, flowers such as cotton grass, grass grass, poppy, and saxifrage grow. Trees in the region include spruce, willow, poplar, birch, and pine.

Animal world

Almost all areas of Eastern Siberia are not distinguished by the richness of their fauna. The reasons for this are permafrost, lack of food and underdeveloped deciduous flora.

The largest animals are brown bear, lynx, elk and wolverine. Sometimes you can see foxes, ferrets, stoats, badgers and weasels. The central zone is home to musk deer, sable, deer and bighorn sheep.

Due to the perpetually 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: wood grouse, crossbill, hazel grouse, goose, crow, woodpecker, duck, nutcracker, sandpiper, etc. .