Features of the relief of northeastern Siberia. Eastern Siberia: Mineral Resources and Relief Questions and Tasks

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-East 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 convex arc 4000 km long to the south. Inside it are the chains of the Chersky ridge stretched parallel to the Verkhoyansk system, the Tas-Khayakhtakh, Tas-Kystabyt (Sarycheva), Momsky ridges, etc.

The mountains of the Verkhoyansk system are separated from the Chersky ridge by a low strip of the Yansky, Elginsky and Oymyakonsky plateaus. In the eastern part, the Nerskoe plateau and the Upper Kolymskoe plateau are located, and in the southeast the Sette-Daban ridge and the Yudomo-Maiskoe 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-Khayata 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 the meridional direction. Along with low ridges (Kharaulakhsky, Selennyakhsky), there are flat ridge-like uplands (Polousny ridge, Ulakhan-Sis) and plateaus (Alazey, Yukagirsky). A wide strip of the coast of the Laptev Sea and the East Siberian Sea is occupied by the Yano-Indigirskaya lowland, from which, along the Indigirka, Alazeya and Kolyma valleys, the intermountain Sredneindigirskaya (Abyiskaya) and Kolymskaya 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 orogeny, two periods are distinguished: the formation of widespread flattening surfaces (peneplains); and the development of intense newest tectonic processes that caused splits, deformation and movement of ancient surfaces of alignment, volcanism, violent erosion processes. At this time, the formation of the main types of morphostructures takes place: folded-block areas of ancient middle massifs (Alazey and Yukagagir plateaus, Suntar-Khayata, etc.); mountains, revived by the newest arch-block uplifts, and depressions of the rift zone (Momsko-Selenyakhskaya depression); folded middle-mountains of the Mesozoic structures (the Verkhoyansk, Sette-Daban, Anyui and other mountains, the Yanskoe and Elga plateaus, the Oymyakonskoe highlands); stratal accumulative, inclined plains, created mainly by subsidence (Yano-Indigirskaya and Kolymskaya lowlands); folded-block ridges and plateaus on the volcanic-sedimentary complex (Anadyr plateau, Kolyma plateau, 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 site of the Verkhoyansk-Chukotka geosynclinal sea basin. This is evidenced by the large thickness of the Paleozoic and Mesozoic deposits, sometimes reaching 20-22 thousand meters, 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 the deposits of the so-called Verkhoyansk complex, the thickness of which reaches 12-15 thousand meters. It includes Permian, Triassic and Jurassic sandstones and shales, usually intensively dislocated and broken by young intrusions.

The most ancient structural elements are the Kolyma and Omolon median massifs. Their base is composed of Precambrian and Paleozoic sediments, and the overlying Jurassic formations, in contrast to other areas, consist of weakly dislocated carbonate rocks, lying almost horizontally; effusive rocks also play a prominent role.

The rest of the tectonic elements of the country are of a younger age, mainly the Upper Jurassic (in the west) and Cretaceous (in the east). These include the Verkhoyansk fold zone and the Sette-Daban anticlinorium, the Yansk and Indigir-Kolyma synclinal zones, and the Tas-Khayakhtakh and Momsky 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 volcanic and terrigenous Jurassic deposits;

d) The main types of relief in Northeastern Siberia form several distinct geomorphological layers. 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 different, than in more southern countries, the altitude limits of the distribution of the corresponding types of mountainous relief. In addition, the processes of nivation, solifluction, and frost weathering are of greater importance in their formation. Permafrost relief forms also play a significant role here, and fresh traces of Quaternary glaciation are characteristic even of plateaus and areas with low mountainous 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 a slightly rugged relief and slight fluctuations in relative heights. Forms are widespread here, owing their origin to permafrost processes, high ice content of loose sediments and the presence of powerful underground ice: thermokarst basins, permafrost heaving mounds, frost cracks and polygons, and high ice cliffs that are intensively breaking down on the sea coasts. Accumulative plains occupy vast areas of the Yano-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 the depressions of the mountainous part of the country (Momo-Selenyakhskaya and Seimchanskaya hollows, Yanskoye and Elga plateau).

Erosion-denudation plains are located at the foot of some northern ridges (Anyuisky, Momsky, Kharaulakhsky, Kular), on the peripheral sections of the Polousny ridge, Ulakhan-Sis ridge, Alazey and Yukagir plateau mountains, as well as on Kotelniy 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 accumulative, these plains are composed of bedrocks of various ages; the cover of loose sediments is usually thin. Therefore, rubble 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 are often found.

The plateau relief is most typically expressed in a wide strip dividing the systems of the Verkhoyansk ridge and the Chersky ridge (Yanskoe, Elginskoe, Oymyakonskoe and Nerskoe plateaus). It is also characteristic of the Upper Kolyma Uplands, the Yukagir and Alazey Uplands, significant areas of which are covered with Upper Mesozoic effusive rocks, lying almost horizontally. However, most of the plateaus are folded by folded Mesozoic sediments and represent denudation flattening surfaces located at an altitude of 400 to 1200-1300 m. The Upper Kolyma Upland, where numerous granite batholiths appear in the form of high dome-shaped hills, prepared by denudation. Many rivers in areas with flat mountain relief are mountainous and flow in narrow rocky gorges.

Low mountains occupy areas that were subjected 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. For the low mountains of North-Eastern Siberia, typical 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 typical for most of the massifs of the Verkhoyansk ridge system, the Yudomo-Maisky Upland, the Chersky, Tas-Khayakhtakh and Momsky ridge. Large areas are also occupied by mid-mountain ranges in the Kolyma Upland and Anyui ridge. Modern high-altitude mountains have arisen as a result of the newest uplifts of the denudation plains of the leveling surfaces, parts of which have been preserved in places here to the present day. Then, in the Quaternary, the mountains underwent vigorous erosional dissection by deep river valleys.

The height of mid-mountain massifs is from 800-1000 to 2000-2200 m, and only at the bottom of deeply incised valleys, the marks sometimes decrease to 300-400 m.Relatively gentle relief forms prevail in interfluvial spaces, 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 everywhere. The development and preservation of these forms is facilitated by the harsh climate, since, in contrast to the more southern mountainous countries, many mid-mountain massifs of the Northeast are located above the upper limit of woody vegetation, in a strip of mountain tundra. The river valleys are quite diverse. Most often these are deep, in places canyon-like gorges (the depth of the Indigirka valley reaches, for example, 1500 m). However, the headwaters of the valleys usually have a wide flat bottom and less elevated 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. These include the ridges of the highest ridges (Suntar-Khayata, Tas-Khayakhtakh, Chersky Tas-Kystabyt. Ulakhan-Chistay), as well as central areas of the Verkhoyansk ridge. 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 kars, circuses and other glacial forms of relief;

e) Among the minerals of this region, one can note numerous deposits of metals, in particular, tin, tungsten, gold, molybdenum, etc. These deposits are associated with Mesozoic-Cenozoic magmatism. The region also has coal and brown coal basins (Zyryanskiy, Verkhoyanskiy).

General characteristics of North-Eastern Siberia

To the east of the lower reaches of the Lena River lies a vast territory, bounded in the east by the mountains 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 square kilometers. Within its borders is the eastern part of Yakutia and the western part of the Magadan region. Northeastern Siberia is located in high latitudes and is washed by the waters of the Arctic Ocean and its seas.

Cape Svyatoy Nos is the northernmost point. The southern regions are in the Mai river basin. To the north of the Arctic Circle, almost half of the country's territory is located, which is characterized by a varied 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.

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Climatic conditions of North-East Siberia are severe, January frosts reach - $ 60, - $ 68 degrees. Summer temperature + $ 30 $, + $ 36 $ degrees. The range of temperatures in some places is $ 100 - $ 105 degrees, little precipitation, about $ 100 - $ 150 mm. Permafrost binds the ground to a depth of several hundred meters. On flat territories, zoning is well expressed in the distribution of soils and vegetation cover - on the islands there is a zone of arctic deserts, mainland tundra, and monotonous swampy larch woodlands. Altitude zoning is typical for mountainous regions.

Remark 1

Pathfinders I. Rebrov, I. Erastov, M. Stadukhin provided the first information about the nature of North-Eastern Siberia. This 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 S.V. Obruchev changed ideas about the peculiarities of this physical and geographical country.

Despite the diversity of the topography, North-Eastern Siberia is mainly a mountainous country, lowlands occupy $ 20% of the area. Here are the mountain systems of the marginal ridges of the Verkhoyansk, Chersky, Kolyma Uplands. In the south of Northeastern 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 summit is in the Ulakhan-Chistai ridge - this is Mount Pobeda, 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 Northeast Siberia belonged to the Verkhoyansk-Chukotka geosynclinal sea basin. The main evidence of this is the powerful Paleozoic-Mesozoic deposits, reaching in places $ 20 - $ 22 thousand meters and strong tectonic movements that created folded structures in the second half of the Mesozoic. The most ancient structural elements are the middle massifs Kolymsky and Omolonsky. Younger age - in the west the Upper Jurassic, and in the east Cretaceous - have the rest of the tectonic elements.

These elements include:

Verkhoyansk fold zone and Sette - Daban aticlinorium;
Yanskaya and Indigirsko-Kolymskaya synclinal zones;
Tas-Khayakhtakh and Momsky anticlinoria.

By the end of the Cretaceous, northeastern Siberia was a territory elevated above neighboring regions. The warm climate of this time, and the denudation processes of the mountain ranges leveled the relief and formed flat surfaces of the alignment. 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. Especially high ridges rose in those areas where the uplifts were most intense. Cenozoic subsidence is occupied by lowlands and intermontane basins with strata of loose deposits.

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

Remark 2

Thus, the glaciation of the plains of North-Eastern Siberia was passive. A significant part of the glaciers were inactive formations that carried a little loose material. The exaration effect of these glaciers on the relief had little effect.

Mountain-valley glaciation is more pronounced; on the outskirts of mountain ranges, there are well-preserved forms of glacial gouging - kars, trough valleys. Valley mid-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;
Bohapcha glaciation.

The first glaciation led to the emergence of Siberian conifers, including the Daurian larch. In the second interglacial epoch, mountain taiga was predominant. 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 displaced to the south.

Relief of the North-East of Siberia

The relief of North-Eastern Siberia forms several well-defined geomorphological layers. Each tier 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 determine other 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, there are:

Accumulative Plains;
Erosion-denudation plains;
Highlands;
Low mountains;
Mid-mountain and low-mountain alpine relief.

Some areas of tectonic subsidence occupy accumulative plains characterized by a slightly rugged relief and small fluctuations in relative altitude. Such forms are spread, which owe their formation to permafrost processes, large ice content of loose sediments and powerful underground ice.

Among them are:

Thermokarst basins;
Frozen 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, Kharaulakh, Kular - formed erosion-denudation plains... The surface of the plains has a height of no more than $ 200 $ m, but it can reach $ 400 - $ 500 $ m on the slopes of a number of ridges. Loose deposits are thin here and they are composed mainly of bedrocks of different ages. As a result, one can find here rubble placers, narrow valleys with rocky slopes, low hills, medallion spots, solifluction terraces.

Between the Verkhoyansk ridge and the Chersky ridge, there is a pronounced plateau relief- Yanskoe, Elginskoe, Oymyakonskoe, Nerskoe plateaus. Most of the plateaus are composed of Mesozoic deposits. Their modern height is from $ 400 to $ 1300 m.

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

Mid-mountain relief is mainly typical for most of the massifs of the Verkhoyansk ridge system. Yudomo-Maisky highlands, Chersky ridge, Tas-Khayakhtakh, Momsky. The Kolyma Upland and Anyui Ridge also have mid-mountain ranges. Their height is 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 woody vegetation.

High alpine relief... These are the crests of the highest mountain ranges - Suntar-Khayata, Ulakhan-Chistay, Tas-Khayakhtakh, etc. They are associated with the regions of the most intense uplifts of the Quaternary period. Height over $ 2000 - $ 2200 m. In the formation of the alpine relief, a significant role belongs to the activity of Quaternary and modern glaciers, therefore, large amplitudes of heights, deep dissection, narrow rocky ridges, kars, circuses and other glacial landforms will be characteristic.

Lesson 48. EASTERN SIBERIA AND NORTH-EASTERN SIBERIA. SPECIFICITY OF NATURE

Option 1

Option 2

1) Set the Match: Natural Frontier

a) the Arctic Ocean;

b) Kazakh Upland. Part of the border

south;

north;

west;

East.

The foundation of the West Siberian platform, in comparison with the East European platform, was formed:

a) earlier;

b) at the same time;

c) later.

The territory of Western Siberia has a general bias:

a) to the north;

b) to the south.

The lower-lying flat topography of Western Siberia is associated with:

a) with a greater depth of the foundation;

b) with the features of the new movements of the earth's crust.

The increasing continental climate of Western Siberia is manifested in:

a) in a colder winter;

in colder winters and more rainfall

1) Set the correspondence:

Part of the border

a) west;

b) east.

Natural frontier

Ural Mountains;

Kazakh Upland;

Yenisei.

The foundation of the West Siberian platform compared to the East European:

a) younger;

b) the same age;

c) more ancient.

The relief of Western Siberia is:

a) the predominance of hills;

b) alternation of highlands and lowlands;

c) the predominance of lowlands.

The thickness of the sedimentary cover on the West Siberian platform in comparison with the East European:

a) less;

b) the same;

c) more.

The main reason for the increase in the degree of continentality of the climate in Western Siberia in comparison with the Russian Plain is: a) the impact of the Arctic Ocean;

reducing the influence of the Atlantic; c) weakening of the western transfer

6) Permafrost in Western Siberia, in comparison with the Russian Plain, has:

a) wider distribution;

b) less widespread.

Western Siberia has the following range of natural zones:

a) from arctic deserts to forest-steppes;

b) from tundra to steppes;

c) from forest tundras to semi-deserts.

The predominant type of soil in Western Siberia:

a) tundra-gley;

b) podzolized;

c) sod-podzolic

6) The boundary of the distribution of permafrost in Western Siberia is shifted in comparison with the East European Plain:

a) to the west;

b) to the north;

c) to the south.

The distribution of natural zones on the territory of Western Siberia is a manifestation of:

a) latitudinal zoning;

b) altitudinal zonality.

The main types of natural resources in Western Siberia are:

a) oil and gas;

b) oil, gas and forest resources;

c) oil, gas, forest and soil resources

Tasks: to form knowledge about the peculiarities of the geographical position of Eastern and North-Eastern Siberia as a factor that determines the natural features of this territory; to develop the skills of students to independently establish a connection between the geological structure and the relief and minerals; to systematize the knowledge of students about the reasons for the formation of a sharply continental climate in Eastern and North-Eastern Siberia; to consolidate the ability to independently determine quantitative climatic indicators for various regions of Siberia and to acquaint with the peculiarities of the climate; study the features of the regime and nature of the flow of rivers and their relationship with the relief and climate of Siberia.

1. Testing knowledge and skills on the topic "West Siberian Plain".

It is advisable to check the level of assimilation of knowledge and skills in a condensed form. Factual knowledge can be tested frontally in the form of a small test for options

Answers:

Option I - 1 - 1 c, 2a, 2 - c; 3 - a; 4 - b; 5 - a; 6 - a; 7 - b; 8 - c.

Option II - 1 - 1a, 2b; 2 - a; 3 - c; 4 - c; 5 - b, c; 6 - c; 7 - a; 8 - b.

II. Obtaining new knowledge.

The study of this topic is complicated by the lack of study time. When preparing for lessons, the teacher first of all selects the main thing, prepares assignments for students' independent work. The methods of organizing cognitive activity can be varied: solving cognitive problems, heuristic conversation, a seminar on the problems of rational use of natural conditions and resources, a game, a competition of characteristics of individual geographic objects, composing crosswords, small travel games.

The teacher distributes the study time at his own discretion. Traditionally, in the first lesson, natural components are considered, in the second, natural complexes are studied.

When studying the nature of Central and North-Eastern Siberia, it is important to draw the attention of students to the understanding of the features of nature, the manifestation of interconnections, the characteristic features and integrity of landscapes. For this, it is advisable to use a heuristic conversation with the practical and independent work of students with maps, a textbook, and visual aids.

1. Students characterize the geographical position of a large natural area "Eastern and Northeastern Siberia" independently, using a physical map of Russia and a map of large natural areas included in the atlas.

Questions and tasks:

1) What are the boundaries of Eastern and North-Eastern Siberia of the natural territory in the north, west, south and east.

2) Specify which landforms are part of Eastern and North-Eastern Siberia.

3) Describe the geographic location of this large natural area.

4) What is the peculiarity of its geographical position in comparison with the West Siberian Plain?

5) How does the Arctic Ocean affect the natural conditions of East and North-East Siberia?

6) How does the Atlantic Ocean affect the natural conditions of this part of Siberia?

7) Explain why the Pacific Ocean, relatively close to Eastern Siberia, has practically no effect on its natural conditions.

8) Make a general conclusion about how the geographical position of Eastern and North-Eastern Siberia affects the natural conditions of the territory.

Summarizing the students' answers, the teacher talks about the size of this natural area and the reasons for close attention to the study of the natural conditions and resources of Eastern and North-Eastern Siberia at the present time.

1) On the tectonic map, establish on which geological structures Eastern and Northeastern Siberia is located.

2) What forms of relief are located in this area?

3) What is the originality of the surface structure?

When characterizing the relief, students pay attention to the fact that the territory of the region is much higher than neighboring Western Siberia. Uplands rise up to 500 m, plateaus - up to 1000 m, uplands - up to 1500 - 2000 m. The highest point is Pobeda Peak in the ridge. Chersky with a height of 3147 m. Thus, a conclusion is formed about the diversity of the relief of Eastern and North-Eastern Siberia.

When analyzing the tectonic map, students are convinced that the Siberian Platform lies at the base of the Central Siberian Plateau. How to explain the structure of the surface and differences in the relief on the plateau? If students have difficulties, then the teacher himself answers this question.

Teacher. The reason for the differences in the relief on the Central Siberian Plateau lies in the unevenness of the platform foundation. Where the foundation comes to the surface, the Anabar plateau was formed. Separate blocks of the basement are omitted, in the relief this is expressed by the lowlands - the North Siberian and Central Yakutsk. A feature of the region's relief is the presence of volcanic plateaus. In the Mesozoic, a huge amount of lava poured out through cracks in the platform, which, solidifying, formed continuous covers. A lot of lava solidified among sedimentary rocks. Subsequently, loose rocks were destroyed, and igneous ones remained, forming a stepped relief - traps. Another feature of the relief is the abundance of kurums. They are formed as a result of intense frost weathering.

4) Using the maps, determine which minerals are mined on the Central Siberian Plateau. Explain why both sedimentary and magmatic minerals are mined on the plateau.

5) What minerals are the mountains of Mesozoic folding and explain why there are many different minerals in these mountains?

The teacher only explains that deposits of ore minerals are associated with traps, and iron ore and diamonds are associated with kimberlite pipes.

Teacher. Interestingly, the discovery of diamonds on the territory of the Siberian Platform is an example of a brilliant confirmation of a scientific prediction. This forecast was made by V.S.Sobolev in 1937 based on a comparison of the geology of the Siberian and African platforms. The search for diamonds began in 1940, and in 1947 the first diamonds were found in placers, and in 1954 the first kimberlite pipes were found. A feature of the development of the mountains of North-Eastern Siberia is the formation of placer gold deposits. Placers are located in terraces, valleys and river beds. They were formed due to the erosion of granite igneous rocks. Gold is a common companion for tin, cobalt, arsenic and other ores.

3. The climatic features of Eastern and North-Eastern Siberia are studied using atlas maps. It is important that schoolchildren independently work through the factual material characterizing the features of the climate, and, relying on it, draw general conclusions about the typical features of the climate of this territory. The teacher organizes the work using the following tasks:

1) For the cities of Norilsk, Irkutsk and Oymyakon, determine the average temperatures in July, January and the annual temperature range; calculate the maximum annual temperature amplitude; calculate the moisture coefficient; determine the types of air masses.

2) On the basis of the obtained climatic data, draw a conclusion about the typical features of the climate of Eastern and North-Eastern Siberia.

Students write down the main features of the sharply continental climate in a notebook:

large fluctuations in daily, monthly and annual temperatures;

low amount of precipitation;

high volatility.

Oymyakon and Verkhoyansk are the cold poles of the northern hemisphere, where the average January temperature drops to -50 °, and the absolute minimum temperature is about -70 ° C.

3) What are the reasons that explain why in the vast territory of Eastern and Northeastern Siberia, stretching from north to south for 2000 km and from west to east for more than 3000 km, a sharply continental climate has formed with very cold winters, the warmest summers and a small amount of precipitation compared to other regions of Russia at the same latitudes.

The task should be completed in writing.

Climatic factors:

northern geographical position;

the influence of the Arctic;

remoteness from the Atlantic Ocean;

significant absolute heights of the terrain;

strong cooling of the mainland in winter, which contributes to the development of stable anticyclones.

4) Remember what kind of weather the winter anticyclones are characterized by and what atmospheric processes are observed in them.

Explanations of the teacher: The Siberian anticyclone is characterized by stable, very cold, clear, sunny, little cloudy, dry and calm weather in winter. The lowest air temperatures are observed in the interior regions of North-Eastern Siberia, in poorly ventilated intermontane basins, where cold air stagnates and is especially strongly cooled. It is in such places that Verkhoyansk and Oymyakon are located. These intermontane basins are characterized by winter temperature inversions in the lower air layer. During inversions, an increase in air temperature with a height of 2 degrees for every 100 m is observed. For this reason, it is less cold on the mountain slopes than in the basins, sometimes this difference is 15-20 °.

4. Characterizing the permafrost, the teacher draws the attention of students to the cause-and-effect relationship in nature.

In one case, permafrost is a consequence of climatic conditions, a sharp continental climate. It is almost ubiquitous throughout the region. The thickness of the permafrost layer in many places exceeds hundreds of meters (in the Vilyui basin - 600 m). In summer, the upper horizon of the frozen strata thaws in the north by 20-40 cm, and in the south by several meters.

In another case, permafrost is the cause that determines the development of other components and natural phenomena. It causes waterlogging of the plains, has a great influence on the regime of inland waters, cools the soil and thereby inhibits the soil-forming process. On permafrost, only plants with a superficial root system, such as larch, can grow.

5. In the final part of the lesson, in order to consolidate the students' skills to establish and characterize the connections of rivers with other components of nature, tasks of a partial search nature are proposed:

Explain why p. The Yenisei is the most abundant river in Russia, despite the fact that there is little rainfall in the basin.

Explain why there are many rapids and waterfalls on the Yenisei, Angara, Vilyue, but not on the Lena.

It is known that winters in Eastern Siberia are characterized by little snow, and in many places the snow is completely swept away. However, in spring, on the rivers of Siberia, there is a high rise in water, which reaches 10 m on the Lena, and even 20 - 25 m on the Lower Tunguska. Explain this natural phenomenon.

III. Summing up the lesson.

Homework: § 37, 38, draw the nomenclature on the contour map.

Covers an area of about 7 million square kilometers. Eastern Siberia is called the region located east of, to the mountains that form a divide between and. The largest area is. In the north and east there are two lowlands: the North Siberian and Central Yakutsk. In the south and west there are mountains (, Yenisei ridge). The length of this area from north to south is about 3 thousand kilometers. In the south, the border with and is located, and the northernmost point is Cape Chelyuskin.

During the Mesozoic period, most of Central Siberia experienced uplift. It is no coincidence that the highest point of the Central Siberian Plateau is located in this area - (its height is 1700 meters above sea level). In the Cenozoic, the uplift of the surface continued. At the same time, a river network was being created on the surface. In addition to the Putorana plateau, the Byrranga, Anabar and Yenisei massifs rose most intensively. Subsequently, active tectonic processes that took place in this area led to a change in the river system. Traces of river systems that existed in ancient times have survived to our time. At the same time, river terraces and deep river valleys in the central part of Siberia were formed.

Cape Chelyuskin

The overwhelming majority of the river valleys of Central Siberia are canyon-like and asymmetric. Their characteristic feature is also a large number of terraces (six to nine), which indicates the repeated tectonic uplifts of the territory. The height of some terraces reaches 180-250 m. On and in the North Siberian lowland, river valleys are younger, and the number of terraces is somewhat less. Even the largest rivers have three or four terraces here.

On the territory of the Central Siberian Plateau, four relief groups can be distinguished:

plateaus, mountain ridges, ridges, and mid-mountain massifs on ledges
stratal heights and plateaus on sedimentary Paleozoic rocks;
plateau
and reservoir-accumulative

Most of the tectonic processes that took place in antiquity and in modern times, on the territory Eastern Siberia coincided in their direction. However, this did not happen throughout the entire territory of the Central Siberian Plateau. As a result of these inconsistencies, depressions similar to the Tunguska were formed. Permafrost is absent (Lena-Angarsk and Lena-Aldan plateaus). But the main small relief forms on the territory of the Central Siberian plateau are still erosional and cryogenic.

Due to the strongest monsoons of the sharply continental characteristic of Eastern Siberia, here you can find a large number of stony placers and talus in mountain ranges, on the slopes of river valleys and on plateau surfaces.