Relief features as a result of the geological history of formation. Features of the relief as a result of the geological history of the formation of the territory

The modern surface of Belarus is represented by an accumulative plain, which combines low, undulating and hilly variants. It is the result of a very long process of interaction between exogenous and endogenous forces, the influence of which is manifested both in the geological and geomorphological structure. The average height of the territory is 150 meters, the height fluctuation is 80 - 346 meters above sea level. Of the total area of the republic of 207.6 thousand square kilometers, low plains account for about two thirds, and uplands with heights of more than 200 meters occupy about one third.

Being the extreme western part of the East European Platform, the territory of Belarus inherited a number of its tectonic elements, which characterize the complexity of the structure of the crystalline basement, which had a certain influence on the formations of a younger relief. According to modern views, the crystalline base of the western part of the East European Plain is strongly broken by deep tectonic faults separating individual structural elements. Structural elements of the first order include uplifts: Belarusian and Voronezh anteclises, Ukrainian shield, depressions: Orsha, Brest (Podlyassko-Brest), Pripyat and Dnieper-Donetsk troughs and saddles: Latvian, Zhlobin, Braginsko-Loevskaya. Closest to the surface, crystalline rocks occur in the south of the territory in the area of the Mikashevichsko-Zhitkovichi horst. The active tectonic life of the platform was expressed in the formation of faults. At the beginning of the Phanerozoic, faults were the site of the formation of rifts, outpourings of volcanic products of the main type, and manifestations of seismicity. In the Phanerozoic, the interaction of endogenous and exogenous processes was expressed in the repeated change of sea and land. Powerful marine deposits of the Devonian, Cretaceous and other geological periods leveled tectonic irregularities and accumulated such minerals as oil, rock and potash salts, coals, oil shale. By the beginning of the Cenozoic, the surface of Belarus was a leveled plain with a developed hydrographic network, with maximum heights up to 180 meters. Despite a significant sedimentary cover, the flat surface retained the features of Precambrian structures that determined the main uplifts and subsidences of the relief. The activity of endogenous processes in the Cenozoic and modern stages of geological history is weakly manifested, which is typical for vast ancient platforms. It is expressed in epeirogenic uplifts and subsidences, in very rare earthquakes (the last one was in 1977). Slow vertical movements and structural features of the basement are found in the structure of the longitudinal and transverse profile of river valleys, the location of lake basins, fluctuations in the level of groundwater, and the intensity of slope processes. An important feature of the modern relief on the territory of the republic should be considered its inheritance from the main structural elements of the platform. This affected the location of large lowlands - Polesskaya and Polotsk, the most significant glacial uplands - the Belarusian ridge (Novogrudok, Minsk, Grodno, Oshmyanskaya), the coincidence of tectonic faults with hollows of glacial ploughing and erosion. The main buried hollows are confined to the arches of tectonic structures, faults, paleovalleys, where their length reaches several tens and even hundreds of kilometers, and the depth of the incision is up to 130-160 meters with deepening of the hollows of glacial gouging and erosion, the lowest elevations of the surface of bedrocks are associated ( Grodno Upland -167 meters, Volkovysk -136 meters). The Dvina-Dnieper hollow is cut into the Devonian rocks by 140 meters. Structural features of the territory are expressed in the structure of large river valleys and lake basins.

Characteristic in this regard are the valleys of the Dnieper, Berezina, Pripyat, Ushach, Braslav, Budovich and other lake groups. A clear connection between the modern relief and geological structures of various orders is noted in Polissya, where the thickness of anthropogenic sediments is small. The composition and conditions of occurrence of rocks of the sedimentary cover were also reflected in the relief. This is manifested, for example, in the spread of underground karst; in areas of close occurrence of karst rocks in Polissya and in the east of the republic, rounded and oval lake basins were formed, separated by ridge-shaped watersheds, which correspond to the eroded surface of limestones.

The modern relief of Belarus was formed as a result of glacial accumulation and exaration, the activity of melt water, subsequent erosion and denudation processes associated with climate and geomorphological processes of the post-glacial period. For the territories of the republic, as well as the entire East European Plain, a five-fold onset of continental glaciation is accepted. The first two epochs - Nareva and Berezina, separated by the Belovezhskaya interglacial, are compared with the Gyunts and Mindel glaciations of Western Europe. The boundary of the ancient glacial epochs reached the southern limits of Belarus, but their deposits are buried under younger sediments. The Berezina glaciation on the East European Plain corresponds to the Oka, and the subsequent Alexandrian interglacial epoch corresponds to the Likhvinian.

The activity of glaciers during the epochs of glaciation was expressed in the formation of marginal uplands, as well as deep troughs of glacial gouging and erosion. In the interglacial epochs, the pradovalleys of modern rivers were formed, the location of which expressed the direction of surface water runoff and the structural features of the territory. In the depressions of the moraine relief, lacustrine reservoirs formed, leaving after their descent a series of typical clays and sands.

The Dnieper glacier, the maximum for the whole of Eastern Europe, covered the entire territory of Belarus. His vigorous activity was expressed in the formation of pressure marginal hills, plowing hollows. In Western Europe, this glaciation is compared with the Rissian.

Numerous outliers and glaciodislocations played an important role in the relief of that time. In the Dnieper time, the main elevations were created on the glacial-accumulative plain of Belarus, reaching 150-180 meters of absolute height. During the next Shklovsky interglacial in Polesie, there was a lacustrine-outland reservoir, after the descent of which a lowland arose, and to the north of it the ancient Baltic-Black Sea watershed was formed. The next interglacial was called the Shklovsky.

The Sozhsky (Moscow) glacier spread within the republic to the south to the line Pruzhany - Bereza - Ivatsevichi - Gantsevichi - Soligorsk - Lyuban - Glussk - Bobruisk - Rogachev - Slavgorod - Kostyukovichi - Klimovichi. Its edge was very winding, small-scalloped and divided into Neman, Minsk and Dnieper streams. Uplands of pre-Moscow age played the role of inter-blade, angular massifs, and glacial lobes occupied surface depressions. The Moscow ice sheet has finally shaped the large uplands of the center of Belarus. Its advance was rhythmic, and each stage and phase of retreat was characterized by the formation of a geomorphological complex, in which there was a frontal upland of the terminal moraine, a prefrontal (proximal) hilly-moraine-lacustrine relief of the bottom-moraine plain, and a postfrontal (distal) outwash-lacustrine belt.

The Neman stream in the Volkovysk and Mostovsky phases completed the formation of the Volkovysk, Grodno, Slonim, Oshmyansk, and partly Novogrudok uplands. The Minsk Stream in different phases of deglaciation created the main part of the Novogrudok Upland, the Kopyl Upland, the complex Minsk Upland, and other sections of the Belarusian Ridge. The Dnieper Stream took part in the creation of the eastern part of the Minsk and Orsha Uplands.

In the Muravino (Mikulino) interglacial, the relief of Belarus was close to modern. This affected the formation of near-glacial lake lowlands, the abundance of small glacial lake basins. The river network south of the border of the future Valdai glacier generally corresponded to the modern one, the watershed line coincided with the highest elevations of the Belarusian Ridge.

The last Poozersky (Valdai) glacier covered only the northern part of the current territory of the republic, but its relief-forming significance is very high. In the south, the border of this glacier passed along the line Grodno - Vilnius - Svir - Myadel - Podsvilie - Lepel - Holopenichi - Orsha. It broke up into three streams - Baltic, Chudsky, Ladoga. The Peipus flow was of primary importance, and at its maximum stage it was divided into the Disna and Polotsk lobes. During the period of active movement and the phase of deglaciation: Ozerskaya (Orsha), Sventsyanskaya, Braslavskaya uplands were formed in the north of Belarus: Sventsyanskaya, Braslavskaya, Neshcherdovskaya, Ushachsko-Lepelskaya, Vitebskaya, Gorodokskaya and other smaller ones. Some of them (Sventsyanskaya, Braslavskaya) have the character of a frontal terminal moraine; Ushach-sko-Lepelskaya is a lobed massif; Vitebsk and Gorodokskaya belong to island corner formations. A typical feature of the uplands is the abundance of lakes, the basins of which were created by the glacier and its waters. The wide distribution of forms of water-glacial accumulation - ozes, kams, limnokams testifies to the solid role of dead ice as a relief-forming factor. The melted glacial waters of the Valdai glacier created a whole system of near-glacial lake reservoirs, the flow from which, at the level of the second floodplain terraces, was directed south along the valleys of the Dnieper, Berezina and their tributaries. These are Polotsk, Disna, Narochano-Vileika, Luchosskoye, Surazhskoye, Verkhneberezinskoye lakes. The descent of reservoirs occurred along a whole system of through river valleys crossing the heights of the Poozersky and Sozh glaciations.

The activity of the melt waters of the last glacier played a big role in the processing of the relief of the central and southern parts of Belarus. Within the uplands, they formed valley sands, filled depressions, rising to a height of more than 150 meters along the slopes, leaving behind rough water-glacial sediments, which, for example, are composed of the Central Berezinsky Plain. In closed depressions and on the slopes of uplands, sediments of a fine granulometric composition also accumulated, providing material for the formation of loess-like rocks. In the south, in the lowland of Polesye, during the epoch of the melting of the Poozersky glacier, there also existed a lacustrine-outland basin, which was later drained by the Pripyat River.

As the ice cover deglaciated, the Baltic-Black Sea watershed was formed, which by the beginning of the Holocene (10 thousand years ago) occupied its present position. The rivers of the Neman and Zapadnaya Dvina basins received flow to the northwest with the help of through valleys. In the river valleys, a floodplain terrace and a floodplain formed.

At the beginning of the Holocene, the descent of the near-glacial lakes ended and the modern pattern of the hydro-network was finally formed, in which the lakes of the last glacial epoch play an important role in the north. The rivers of the central part of Belarus developed an equilibrium profile, their deep terraced valleys dissected moraine heights, giving the largest of them the appearance of low mountains with relative heights of 40-60 meters. Polissya acquired the character of an alluvial lowland, formed mainly by two levels of the floodplain and the Pripyat terrace above the floodplain. On the surface of the Polesskaya lowland, flat depressions, occupied by marshy lowlands and shallow lakes, acquired a noticeable role. They are outlined by crescent-shaped sandy parabolic Polissya dunes. Similar dunes formed at the beginning of the Holocene on the surface of sandy near-glacial lake lowlands in the north. An important event of the Late Glacial and Early Holocene was the afforestation of thin elutriated water-glacial, deluvial and eolian sediments that covered the slopes of the uplands. Their thickness varies from 2 - 3 meters in the center to 5 - 8 in the east. Loess-like rocks contributed to the leveling of the surface of the uplands and, at the same time, to the secondary erosional dismemberment of their slopes by gully-gully systems. Characteristic in this regard are the southwest of the Minsk, Novogrudok, Kopyl, Orsha, Mozyr uplands, the depth and frequency of ravine dismemberment of which is not inferior to the Central Russian Upland and reaches 3-4 square kilometers.

Relief typification

In order to understand the features of the relief, it is necessary to know the geological history of its formation. Scientists, studying the layers of rocks, found out that all of them have come a long way of formation and have a different age. You will learn about this from this lesson, having made a fascinating journey through the history of the development of the earth's crust. And also, learn to read the geochronological table and get acquainted with the geological map.

Topic: Geological structure, relief and minerals

Lesson: Features of the relief as a result of the geological history of the formation of the territory

To understand the pattern of formation of mountains and plains, it is necessary to get acquainted with the history of the geological formation of the territory. The history of the geological development of any territory is learned by studying the age, composition and occurrence of rocks. It is from these data that one can find out what happened to the territory in distant geological epochs, whether the territory was covered by the sea or volcanoes erupted, whether there were deserts or glaciers here.

Some parts of the earth's surface are composed of ancient metamorphic rocks, others are young volcanic, and still others are sedimentary. Rocks can lie horizontally or form folds. All rocks have an absolute or relative age. . Relative age is defined by the concepts of "old" and "younger". Sedimentary and volcanic rocks accumulate in horizontal layers and it is therefore natural to assume that the older ones are deeper and the younger ones are closer to the surface. (see fig. 1)

Rice. 1. Occurrence of layers of sedimentary rocks

help determine relative age and ancient fossils. (see fig. 2)

Rice. 2. Trilobite. Age about 380 million years

Powerful strata of sedimentary rocks are formed at the bottom of the oceans. The ocean once covered the vast territories of our planet and various animals lived in it, which died and settled to the bottom, were covered with sand, silt, soft tissues decomposed, and hard tissues became fossils.

The more complex the organism is, the younger the rock; the simpler, the older. Absolute age breeds is the number of years that have passed since the formation of these breeds.

The study of rocks, extinct remains of animals and plants, made it possible to identify several stages in the formation of the geological history of our planet. These stages are reflected in the geochronological table ("geo" - earth, "chronos" - time, "logos" - doctrine). The geochronological table is a geological record of events taking place on our planet. The table shows the sequence and duration of the change of various geological stages, and the table can also present various geological events in different periods, typical animals, as well as minerals that were formed in different eras. The geochronological table is built on the principle: from ancient to modern, so you need to read it from bottom to top. (see fig. 3)

Rice. 3. Geological table ()

According to the most significant changes that have occurred on our planet in the geological past, all geological time is divided into two large geological segments - eons: Cryptozoic- time of hidden life, Phanerozoic- explicit life time. The aeons include era: Cryptozoic - Archean and Proterozoic, Phanerozoic - Paleozoic, Mesozoic and Cenozoic. (see fig. 4)

Rice. 4. Division of geological time into eons and eras

The last three eras: Paleozoic, Mesozoic, Cenozoic are divided into periods, due to the fact that the geological world was very complicated at that time. The names of the periods were given according to where rocks of a given age were first discovered, or according to those rocks that make up a particular area, for example: Permian and Devonian by the name of the area, and Carboniferous, or Cretaceous by rocks. We live in the Cainozoan era, the modern one, which continues to this day. It began about 1.7 million years ago. (see fig. 3)

Let's consider some characteristics of geological eras. archaeus and Proterozoic considered the time of hidden life (Cryptose). It is believed that the organic life forms that existed at that time did not have hard skeletons, so they did not leave any traces in the sediments of these eras. (see fig. 5)

Rice. 5. Cryptozoic (Archaean and Proterozoic) ()

The time of domination of invertebrates, crustaceans, insects, mollusks. In the late Paleozoic, the first vertebrates appeared - amphibians, fish. The plant kingdom was dominated by algae and pselophytes . Later, horsetails and club mosses appear. (see fig. 6)

Rice. 6. Paleozoic ()

Large reptiles dominate in the Mesozoic, and gymnosperms dominate in the plant world. .(see fig. 7)

In the Cenozoic - the dominance of angiosperms flowering plants, the appearance of mammals and, finally, humans. (see fig. 8)

Rice. 8. Cenozoic ()

In each of the geological epochs and periods, the accumulation of the chemical and mechanical composition of rocks took place. In order to find out what rocks this or that territory of our country is composed of, we can use the geological map of Russia. (see fig.9)

Rice. 9. Geological map of Russia ()

Geological map contains information about the age of rocks, about minerals. Information on the map is shown in different colors. If you look at the geological map, you will see that the most ancient rocks form the territory of Transbaikalia and the Kola Peninsula.

Different periods are shown in different colors, for example, the Carboniferous rocks are shown in grey, while the Mesozoic rocks are shown in green. Analyzing the geological map, one can pay attention to the fact that the East European Plain is composed of rocks of the Paleozoic era, and only in the Far North-West we see outcrops of rocks of the Archean and Proterozoic period. The West Siberian lowland is composed of young deposits of the Paleogene and Neogene.

Using geological maps, you can get information about minerals, as well as predict their search.

The geological age of our planet is approximately 4.7 billion years. It was during this period that the core, the mantle, were formed as a result of the differentiation of matter. (see fig. 10)

Rice. 10. The internal structure of the Earth

The earth's crust is broken into blocks - lithospheric plates. Moving through the mantle, lithospheric plates changed the outlines of continents and oceans. (see fig. 11)

Rice. 11. Lithospheric plates

There were periods when the lithospheric plates descended, and then the land area decreased, and the area of the World Ocean increased. Such eras, more peaceful in geological terms, were called epochs of the seas. They alternated with geologically more turbulent and shorter periods, which were called epochs of land. These epochs were accompanied by active volcanism and mountain building.

Homework

Using the geochronological table, determine which periods are older: Devonian or Permian, Ordovician or Cretaceous, Jurassic or Neogene?
Which of the eras is more ancient: Proterozoic or Mesozoic, Cenozoic or Paleozoic?
What era and period are we living in?

Geography of Russia. Nature. Population. 1 hour Grade 8 / auth. V.P. Dronov, I.I. Barinova, V.Ya Rom, A.A. Lobzhanidze
Geography of Russia. population and economy. Grade 9 / author V.P. Dronov, V.Ya. Rum
Atlas. Geography of Russia. Population and economy / publishing house "Drofa" 2012
TMC (educational kit) "SPHERES". Textbook "Russia: nature, population, economy. Grade 8 "author. V.P. Dronov, L.E. Savelyeva. Atlas.

Other tutorials on this topic

The structure of the earth's crust (lithosphere) in Russia ().
The relief of Russia, the geological structure and minerals ().

Find out more on the topic

Relief, geological structure and minerals ().
The history of life on Earth ().
Interactive geological atlas of Russia ().
Site of the Mineralogical Museum named after A.E. Fersman ().
Website of the State Geological Museum named after V.I. Vernadsky ().

Video Lesson 2: Relief of Russia

Lecture: Features of the geological structure, the distribution of large landforms in Russia

Geological structure

The formation of the earth's crust began 3.5 billion years ago. The formation of the earth's surface took place in several stages.

Geological era is a long period of formation of the Earth's surface.

There are 5 of them in total. Eras unite geological periods.

Russia is located on the Eurasian continent, on the Eurasian lithospheric plate. The structure of the plates is not the same in tectonics. There are relatively stable and mobile areas. Stationary sections are called platforms. Mobile - mobile folded belts. The location of the main landforms is determined by the structure of the Eurasian plate.

The territory of the country lies on the East European and Siberian platforms. These territories are stable. At the base is a fixed foundation, covered with a layer of sedimentary rocks. The foundation was formed in the Precambrian period, it is composed of granites, quartzites, shales, gneisses. Sedimentary rocks have a horizontal structure. Each layer of rocks corresponds to a certain time of deposition. There are places where the foundation of the slab comes to the surface. Such places are called shields. For example, the Aldan shield on the Siberian platform.

At the boundaries of the lithospheric plates there are seismically active areas, accompanied by movements of the earth's crust, volcanic eruptions. Such areas affect part of Russia: the Kuril Islands and the Kamchatka Peninsula. These territories are part of the Pacific Ring of Fire. The southern territory is occupied by mountain ranges, there is a general slope to the north. Major rivers of the country flow to the north. On the territory of our country there are mountain belts in the middle of a fixed plate, for example, the Ural Mountains. From which we can conclude that once this territory was seismically active, there was a boundary between two lithospheric plates, which later merged. Folded areas were formed at different times: Paleozoic, Mesozoic, Cenozoic folding. The Urals and Western Sayan are areas of Paleozoic folding. Folded areas of the northeastern part belong to the areas of Mesozoic folding.
The elevation difference is about 5670 m.

Landforms

Tectonic processes have formed the main landforms.

relief formation is a continuous process that is transforming the surface of the land at the present time.

There are internal and external processes. The internal ones include the movements of the earth's crust, the external ones are the activity of water, wind, glaciers, and permafrost.

The East European Plain is located in the western part, it is separated from the West Siberian Plain by the Ural Mountains. The Central Siberian plateau occupies the central part. The eastern and southeastern parts are occupied by mountains, ranges, and highlands. The largest of them: the Sayan Mountains, Altai, the Verkhoyansk Range, the Stanovoy Range, the Aldan and Chukchi Highlands. Negative landforms are of tectonic and glacial origin, for example, Lake Baikal is of tectonic origin.

Ancient glaciation

The ancient Quaternary glaciation had a great influence on the relief. The glacier originated in the north of the mainland, and from there it moved in three directions. The movement of the glacier transformed the earth's surface: the mountains were smoothed out, in the areas of the melting of the glacier, sedimentary and rocks brought by the glacier remained. These deposits are called moraine, respectively, the relief in such areas is called moraine. After the melting of the glacier, large streams of water formed, which carried sand with them. With the deposition of sand, flat land areas were formed. The same waters filled all the low areas of land, forming lakes of glacial origin, located in the north of the Russian Plain.

Influence of flowing waters on the relief structure

Flowing waters have tremendous power, capable of transforming the earth's surface, creating ravines, gorges, hollows. They also have storage energy, able to carry sand and stones. Sand usually settles in places where the river flows calmly. Flowing waters form a water-erosive relief, characteristic of mountainous areas with sufficient moisture.

Weathering

The activity of the wind affects the relief. The wind destroys sandy landforms, the sand is transferred to another place, where it forms new landforms - dunes. A striking example is the Caspian lowland, where an aeolian relief was formed with the help of the wind.

1) Baltic 2) Bering 3) Barents. 4) northern

2. The indigenous peoples of the European north include:
1) Bashkirs. 2) Tuvans. 3) Komi. 4) Chuvash

3. Which of the following industries has the largest share in the economy of the European North?
1) light. 2) metallurgy. 3) food. 4) chemical

4. the main center of the coal industry of the European north is the city:
1) Arkhangelsk. 2) Murmansk. 3) Vorkuta. 4) Syktyvkar

5. To the border with which European states does the territory of the European North have access?
1) Denmark and Norway
2) Denmark and Sweden
3) Sweden and Finland
4) Finland and Norway

6. The indigenous peoples of the European north include:
1) Adyghes. 2) Kalmyks. 3) Buryats. 4) Karelians

7. Which of the branches of engineering has received the most development in the European north?
1) automotive industry
2) machine tool building
3) aircraft building
4) shipbuilding
Please help guys!

What areas borders the Volga region? 1) European South, Central Russia and Urals 2) Urals, European North and European South 3) Western

Siberia, the Urals and the European South

4) Central Russia, European South and Western Siberia

Which statement about the geographical location of the Volga region is true?

A) The region has an advantageous transport and geographical position, its territory is crossed by a dense network of railways and roads, a network of pipelines.

B) The Volga region occupies an inland position, but thanks to the canal system it has access to the Baltic, Black, Azov and White Seas.

1) only A is true 3) both are true

2) only B is true 4) both are true

Which of the following statements correctly characterizes the climate of the Volga region?

1) The region is characterized by high summer temperatures, arid climate and uneven precipitation.

2) The climate on the Volga Upland is drier and more continental than in the Trans-Volga region.

3) In the Trans-Volga region, winters are warmer and more snowy than in the Volga region.

4) In most of the area, the moisture coefficient is greater than or equal to one.

The food of the rivers of the Volga region is mainly:

1) rainy 3) glacial

2) snow 4) underground

What natural resources are rich in the Volga region?

1) forest and fish

2) agro-climatic and land

3) mineral and forest

4) biological and recreational

What minerals are mined in the Volga region?

1) nickel ores 3) apatites

2) table salt 4) peat

City-millionaire in the Volga region:

1) Samara 2) Penza 3) Astrakhan 4) Saratov

The second most populous people of the Volga region:

1) Russians 2) Tatars 4) Kalmyks 4) Bashkirs

Which of the following industries has received the most development in the Volga region?

1) timber industry 3) ferrous metallurgy

2) chemical industry 4) non-ferrous metallurgy

In terms of the level of development of mechanical engineering, the Volga region is inferior to:

1) Central Russia 3) European Northwest

2) Ural 4) Western Siberia

Most of the oil is processed at refineries:

1) Samara region 3) Astrakhan region

2) Saratov region 4) Republic of Tatarstan

Large fish processing center:

1) Volgograd 2) Samara 3) Astrakhan 4) Kazan

1. Evaluate the features of the EGP, the geopolitical position of the European North. 2. What determines the specifics of the ecological and geographical position of the area?