Features of the relief as a result of the geological history of the formation of the territory. The history of the formation of the relief How the features of the formation of the relief of the territory influenced

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.

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, molluscs. 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 ().

The relief is all the irregularities of the earth's surface, which is formed due to the interaction of the internal and external forces of the Earth.
Landforms are distinguished by size, structure, origin, etc. There are convex (positive) and concave (negative) relief forms.

At the heart of the territory of the Russian Federation are large tectonic formations - shields, platforms, folded belts, the impact of which is expressed in the versatility of the relief of our state. So, Russia is characterized by numerous lowlands, uplands, as well as mountain systems.

The structure of the earth's crust

The largest features of the country's relief are determined by the peculiarities of the geological structure and tectonic structures. The territory of Russia, like the whole of Eurasia, was formed as a result of the gradual convergence and collision of individual large lithospheric plates.
The structure of lithospheric plates is heterogeneous. Within their limits there are relatively stable areas - platforms and mobile folded belts. The location of the largest forms of land relief - plains and mountains - depends on the structure of lithospheric plates. Areas with a flat relief are confined to platforms - stable areas of the earth's crust, where folding processes have long ended.

The most ancient of the platforms are East European and Siberian. At the base of the platforms lies a rigid foundation composed of igneous and highly metamorphosed rocks of the Precambrian age (granites, gneisses, quartzites, crystalline schists). The foundation is usually covered with a cover of horizontal sedimentary rocks, and only on the Siberian Platform (Central Siberian Plateau) are significant areas occupied by volcanic rocks - Siberian traps. The outcrops of the foundation, composed of crystalline rocks, to the surface are called shields. In our country, the Baltic Shield on the Russian Platform and the Aldan Shield on the Siberian Platform are known.

Mountainous regions are distinguished by a more complex geological structure. Mountains are formed in the most mobile parts of the earth's crust, where, as a result of tectonic processes, rocks are crushed into folds, broken by faults and faults. These tectonic structures arose at different times - in the eras of Paleozoic, Mesozoic and Cenozoic folding - in the marginal parts of the lithospheric plates during their collision with each other. Sometimes folded belts are located in the inner parts of the lithospheric plate (Ural Range). This indicates that once there was a boundary between two plates, which later turned into a single, larger plate.

The youngest mountains of our country are located in the Far East (Kuril Islands and Kamchatka). They are part of the vast Pacific volcanic belt, or the Pacific Ring of Fire, as it is called. They are distinguished by significant seismicity, frequent strong earthquakes, and the presence of active volcanoes.

When looking at the map, two features of the Russian relief are striking:
1) the predominance of plains in the western and central parts of the country, and mountains - along its eastern and partly southern outskirts;
2) lower altitude position of the western part compared to the eastern.
The border between them is clearly visible in the prevailing coloring of the map and clearly coincides with the Yenisei valley. The third feature can be traced upon a more detailed examination of the map: the greater height of the southern mountains compared to the eastern ones. The Caucasus and Altai are among the high mountains of Eurasia.

Plains occupy about 60% of the country's territory. They stretched from the western borders of Russia to the Lena, from the coast of the Arctic Ocean to the foothills of the Caucasus, Altai and Sayan Mountains. The two largest plains of Russia - East European and West Siberian - are among the greatest plains in the world.

The East European Plain stands out among other plains with the most diverse relief. There are large hills, some marks of which exceed 300 and even 400 m (the highest point of the Bugulmino-Belebeevskaya upland reaches 479 m), and vast lowlands with small hills and ridges scattered over them (in the north) or rather monotonous (Caspian region). The lowest parts of the plain are located in the coastal strip of the Caspian Sea with a height of 26 m. The average height of the plain is 170 m.

In the extreme north-west of the country, within the Kola Peninsula, on the large intrusive massifs of the Khibiny, Lovozero and Monchetundra, some peaks exceed 1100 m; the highest of them is Mount Chasnachorr (1191 m) in the Khibiny.
The West Siberian Plain is characterized by an exceptionally uniform relief with slight elevation fluctuations. Only some small areas in the marginal parts of the plain exceed 200 m. It reaches its maximum heights on the North Sosvinskaya (290 m) and Verkhnetazovsky (285 m) uplands. Almost half of the territory lies below 100 m above sea level. The average height of the plains is only 120 m.
The East European and West Siberian plains are separated by low and narrow (up to 150 km) Ural Mountains, only some peaks of which exceed 1500 m. The highest point of the Urals is Mount Narodnaya (1895 m).

In the interfluve of the Yenisei and Lena, the Central Siberian Plateau is located - a plain raised to a considerable height (up to 400-600 m and higher) and deeply dissected by large river valleys. It reaches its highest heights within the Putorana Plateau (1701 m). The average height of the plateau is 480 m.
To the east, the Central Siberian Plateau gradually passes into the Central Yakut Plain, and to the north it descends in a steep ledge to the North Siberian Lowland.

The mountain frame in the southwest is represented by the mountains of the Greater Caucasus, stretching from the Black Sea to the Caspian. Here is the highest point of Russia - the two-headed Elbrus (5642 m) and all the other "five-thousanders". From Altai begins the southern mountainous belt of Siberia. It is represented by high and mid-mountain ridges of Altai (Belukha - 4506 m) and Sayan (Mount Munku-Sardyk - 3491 m), mountain ranges and highlands of Tuva, Baikal and Transbaikalia. In Transbaikalia, the peaks of the Stanovoy Upland reach the highest heights (the highest point is 3073 m). Through the Stanovoy Range, the mountains of southern Siberia are connected with the mountain structures of the eastern outskirts.

To the east of the Lena and up to the shores of the Pacific Ocean, there are medium-altitude ridges and highlands: Verkhoyansky (2389 m), Chersky ridge (Pobeda - 3003 m), Suntar-Khayata (2959 m), Dzhugdzhur (1906 m), Yano-Oymyakonskoe , Kolyma, Chukotka, Koryakskoe (Ice Mountain - 2453 m). To the south, they pass into the low and medium-altitude ridges of the Amur region, Primorye (Sikhote-Alin) and Sakhalin, the maximum heights of which do not reach 2500 m. The eastern outpost is represented by the folded and volcanic mountains of Kamchatka and the Kuriles. In Kamchatka, there is the highest point of the Asian territory of Russia - the active volcano Klyuchevskaya Sopka (4688 m). All the highest peaks of Kamchatka and the Kuriles are active or extinct volcanoes.

The territory of Russia is characterized by the predominance of low and medium-altitude mountains. Mountains over 1500 m high occupy less than 10% of the country's area.
Thus, the eastern and southeastern outskirts of Russia are represented by mountain structures. In the southwest, near the southern border of the East European Plain, the lonely Caucasus rises.

The main landforms of Russia - plains, mountains and highlands - owe their origin to the internal forces of the Earth. But many essential details of their modern relief were created by external forces. Almost everywhere the formation of the modern relief took place and is taking place under the influence of flowing waters. As a result, erosional landforms were formed - river valleys, beams and ravines. The ravine-gully network is especially dense on such uplands as the Central Russian, Volga, and in the foothills. Many coastal sea plains have a flat, level topography that has been shaped by processes associated with the advance and retreat of the sea. Therefore, on vast expanses of modern land, marine sediments lie horizontally. Such are the plains of the Caspian, Black Sea, Azov, Pechora and northern parts of the West Siberian lowlands.

In the vast territories of our country, many landforms were created as a result of Quaternary glaciations. Their influence is especially great in the northern half of the European part of Russia, which was repeatedly covered with glaciers descending far to the south from the Scandinavian mountains and the Polar Urals. Traces of the activity of the glacier on the plains are numerous hills and ridges composed of moraine. Landforms that arose as a result of the activity of melted glacial waters are also widespread here. These are hills and flat sandy plains, diverse in form and material composition. Similar relief forms associated with the activity of the glacier and its melt waters are also found on the territory of Western and Eastern Siberia. But here they occupy a smaller area, since glaciation in these areas was less intense: in conditions of a sharply continental climate, where there is little precipitation, glaciers of considerable thickness could not form.

Mountain glaciers in the Quaternary existed in almost all mountains. The highest of them still have glaciers. Traces of former mountain glaciations are such landforms as cirques and trough valleys. They are widespread in the Caucasus, the Urals, the Sayans, Altai and many other mountains of Russia.
In a number of regions of Russia there are relief forms formed by the activity of the wind. They are especially widely represented in arid regions of the country. So, in the deserts of the Caspian Sea, sandy hills were formed - dunes and ridges. Eolian forms are also found in humid areas. The dunes of the Baltic States arose as a result of winnowing the sand of sea beaches and spits.

In the north of the European part of the country and east of the Yenisei, landforms associated with permafrost strata are found almost everywhere. Heaving mounds are especially common, resulting from freezing of groundwater, various kinds of subsidence of soil over areas of thawing frozen rocks. These processes interfere with construction, often accompanied by the destruction of roads, houses and industrial buildings.

The Caspian lowland is the lowest point of the Russian relief