General information
The eastern part of Russia is characterized by the widespread development of mountain-folded regions of Mesozoic and Alpine age, which are part of the Pacific fold belt. Mesozoids are mountainous folded areas that completed their geosynclinal development in the Cretaceous period. However, typical platform development within their boundaries has not yet begun. The earth's crust has not acquired sufficient strength and thickness here. Examples of them are the Verkhoyansk-Kolyma (Verkhoyansk-Chukotka) and Far Eastern (Sikhote-Alin) regions.
The Verkhoyansk-Kolyma region occupies vast areas of the northeastern part of Russia. In the north, this region is washed by the Laptev and East Siberian seas. It also includes the islands of Novosibirsk, De Long, Lyakhovsky, Wrangel and others.
Stratigraphy
Precambrian deposits found within the most ancient massifs of the Verkhoyansk-Kolyma region. They are represented by deeply metamorphosed gneisses, crystalline schists, and amphibolites. In composition and appearance, these rocks are close to the rocks of the Archean complex of the Aldan Shield of the Siberian Platform.
Proterozoic formations are represented by various schists, quartzites, and marbled limestones. The deposits are intruded by granite intrusions. The total thickness of the Precambrian strata is over 5 km.
Breeds Paleozoic group combine sediments of Cambrian - Permian age. Paleozoic formations emerge on the surface only in the cores of anticlinoria. At the same time, Permian deposits are more widely developed. In the Paleozoic group, two strata are distinguished. Lower includes breeds from Cambrian to Lower Carboniferous. It is represented by alternating limestones, marls, dolomites, shales, and sandstones.
There are interlayers of conglomerates (Devonian) and effusive rocks (Cambrian, Devonian). There are intrusions of gabbrodiabases and granites. The total thickness of the Paleozoic terrigenous-carbonate strata is more than 15 km.
The Verkhoyansk complex, which includes Upper Paleozoic strata And lower Mesozoic(Middle and Upper Carboniferous, Permian, Triassic, Lower and Middle Jurassic). The complex is composed of uniformly interbedded dark gray and black sandstones, clayey shales with rare interlayers of limestone. Its thickness exceeds 10 km.
Mesozoic group(Upper Jurassic - Cretaceous) is widespread within the Verkhoyansk-Kolyma region. Upper Jurassic It is represented by terrigenous carbon-bearing deposits with interlayers of conglomerates and volcanic rocks (porphyrites and diabases) with a total thickness of more than 2 km. Lower Cretaceous composed of volcanic-terrigenous strata with layers of coal. The thickness of the thickness is up to 1 km. Along the coast of the Sea of Okhotsk, the thickness of the Lower Cretaceous volcanogenic formations reaches 3 km. The deposits of the Verkhoyansk complex of the Upper Jurassic and Lower Cretaceous are metamorphosed and folded into various folds. Only within the ancient middle massifs of the Verkhoyansk-Kolyma region do they lie almost horizontally.
Upper Cretaceous lies unconformably throughout and is composed of typically continental sediments. These are sands, clays, sometimes with layers of coal (lower reaches of the Kolyma and Indigirka rivers). Acid effusives and their tuffs are widespread. The thickness of the Upper Cretaceous is up to 1 km.
Sediments Cenozoic group are not widespread. Paleogene It is represented by thin sandy-clayey continental sediments and rather significant effusive strata of acidic composition.
Neogene deposits are known in river basins and intermountain depressions. These are continental terrigenous sediments of low thickness.
Lntropogenic the formations consist of glacial, alluvial, colluvial and marine sediments up to 100 m thick.
Objectives: to introduce the influence of internal and external factors on the formation of relief; show the continuity of relief development; consider the types of natural phenomena, the causes of their occurrence; talk about the influence of man on the terrain.
Equipment: physical map, tables, pictures, video about natural phenomena, books, diagrams.
During the classes
I. Organizational moment
II. Checking homework
1. Repetition of terms and concepts
Platform, shield, folded region, tectonics, paleontology, deposit.
Option 1
1. Stable areas of the earth’s crust are called:
a) platforms;
c) folded areas.
2. The plains are located:
a) at the boundaries of lithospheric plates;
b) on platforms;
c) in folded areas.
3. The mountains are located:
a) on platforms;
b) on slabs;
c) in folded areas.
4. The following ridges rose into the Mesozoic folding:
b) Sikhote-Alin;
c) Caucasus.
5. The reborn mountains are:
b) Caucasus;
6. Deposits are confined to ancient folded areas:
a) coal, oil, gas;
b) iron ores, gold;
c) both.
7. The largest coal basins are:
a) Samotlor, Kansko-Achinsky;
b) Tunguska, Lensky;
c) Urengoy, Yamburg.
8. Landforms of glacial origin include:
a) moraines, trogs, sheep's foreheads;
b) ravines, beams;
c) barchans, dunes.
9. The surface of Russia goes down:
b) to the north;
c) to the west;
d) to the east.
Answers: 1 - a; 2 - b; 3 - in; 4 - b; 5 - a; 6 - b; 7 - b; 8 - a;
Option 2
a) Proterozoic;
b) Paleozoic;
c) Archean.
2. The geological era, which continues today, is called:
a) Mesozoic;
b) Cenozoic;
c) Paleozoic.
3. The science of minerals is called:
a) petrography;
b) paleontology;
c) geotectonics.
4. Find a correspondence between the mountains and their highest peaks:
1) Caucasus: a) Victory;
2) Altai; b) Belukha;
3) Sayans; c) Elbrus;
4) Chersky ridge. d) Munku-Sardyk.
5. Choose the correct statements:
a) large plains are located on platforms;
b) aeolian processes create moraines:
c) the Kamchatka peninsulas and the Kuril Islands - the most seismically active zones in Russia;
d) the main part of the mountains is located in the west and north of Russia;
e) the Ural Mountains are located between the Russian and West Siberian plains.
6. Find correspondence between concepts and their definitions:
1) mud-stone flow;
2) snow melting from mountain slopes;
3) loose clay-boulder glacial deposits.
a) avalanche;
c) moraine,
7. Which map shows the structure of the earth's surface (crust)?
a) on the physical;
b) on geological;
c) on tectonic.
Answers: 1 - in; 2 - b; 3 - a; 4 - 1) c, 2) b, 3) d, 4) a; 5 - a, c, d; 6 - 1) b, 2) a, 3) c; 7 - c.
III. Learning new material
(The following concepts are written on the board: endogenous processes, exogenous processes, volcanism, earthquakes, recent tectonic movements, glaciation, moraines, aeolian relief, dunes, screes, landslides, avalanches, mudflows, erosion.)
Look at the blackboard. We will look at these terms today in class, and remember some of them.
The relief is constantly changing under the influence of exogenous (external) and endogenous (internal) factors.
(The teacher draws a diagram on the board while giving explanations.)
The relief is constantly changing under the influence of exogenous (external) and endogenous (internal) factors. Both of these factors act simultaneously.
Endogenous processes are called neotectonic or recent. They can appear in both mountains and plains.
In the mountains, movements of the earth's crust are most active. In the Caucasus, movements occur at a speed of 5-8 cm per year; in young mountains, where the earth's crust is plastic, movements are accompanied by the formation of folds. In areas of ancient folding (Urals, Altai, Sayans, etc.), where the earth's crust is more rigid, faults and normal faults are formed. The areas undergo vertical movements, some blocks rise, others fall, forming intermountain basins.
On the platforms, the latest movements are manifested in centuries-old slow fluctuations of the earth's crust, some areas slowly rising, while others are falling at a rate of about 1 cm per year. But there can also be faults on platforms, an example of this is the faults in eastern Africa (Great African Rifts).
Exogenous processes are processes that occur under the influence of flowing waters (rivers and glaciers, mudflows), permafrost, and wind.
Glacial landforms
During the Quaternary period, a huge shell of ice up to 4 km thick buried almost all of Europe. The centers of glaciations were Scandinavia, the Polar Urals, the Putorana Plateau and the Byrranga Mountains on the Taimyr Peninsula. The cold was advancing on the Earth in giant waves. There were several such waves. The formation of glaciers is associated with them. Since the Cambrian, scientists have counted up to five such glaciations. At the beginning of the Quaternary period, the great glaciation began for the fifth time. This happened more than 200 thousand years ago. The glacier retreated relatively recently - only 12-15 thousand years ago.
1. Moraine (French moraine) - a geological body composed of glacial deposits. The boulders in moraines consist mainly of granites and gneisses. In addition to rounded boulders, on the surface of the moraine there are sometimes large, up to several tens of meters in diameter, poorly rounded boulders of rapakivi granites - outliers. The colossal boulder is widely known, which was used as a pedestal for the installation of the monument to Peter 1 in St. Petersburg. This boulder, called the “Thunder Stone,” was found near the village of Lakhta on the shores of the Gulf of Finland. Its length is 13 m, width - 7 m, height - 8 m. Delivery to St. Petersburg took two years.
The moraine is an unsorted mixture of clastic material of various sizes - from giant boulders with a diameter of up to several hundred meters, to clay and sandy material formed as a result of the grinding of debris by the glacier as it moves. It is difficult to note any pattern in the distribution of fragments of different sizes in the body of the glacier, therefore the rocks deposited by the glacier are unsorted and unlayered.
2. Terminal moraine ridges are the boundaries of glacier movement and represent brought debris material. Enormous terminal moraines and associated water-glacial ridges are located in Finland and on the Karelian Isthmus. These include the Michurinskaya ridge and the Northern Uvaly, which are a water-glacial formation.
3. On the Baltic and Canadian shields, the rocks are smoothed by the glacier, there are numerous ram's foreheads - protrusions of igneous and metamorphic rocks with scratches and scars on the surface; slopes facing the movement of the glacier are gentle, those opposite are steep.
4. Oz (ridge, ridge) is a ridge with rather steep slopes (30-45°), reminiscent of a road embankment. The eskers are usually composed of sand, often with pebbles and gravel; pine loves sandy soils, so it often grows on eskers. There is no consensus on the origin of ozkes. There is a water flow along the glacier, it carries a lot of sand, pebbles, and boulders; Having reached the edge of the glacier, the flow forms a fan, the edge of the glacier retreats, and the cone retreating with it gradually forms a ridge. There is another explanation: a stream flowing on the surface of a glacier or inside it deposits sandy rocks with large fragments along its bed; when the glacier melts, all these sediments fall on the underlying surface, forming a ridge on it. One way or another, eskers are formed by streams flowing along the glacier or in it, which is confirmed by the layering of the rocks that make up the esker, such as is formed by water flows. The height of the escarpment can reach several tens of meters, the length - from hundreds of meters to tens (occasionally even hundreds) of kilometers. The peculiarity of eskers is that they do not take into account the relief at all: an esker ridge can stretch along a watershed, then go down a slope, cross a valley, rise again, then go into the lake, forming a long peninsula, dive and emerge on the other side. And so on until its length is enough.
5. Kom (English kate or German katt - ridge) is a hill, externally usually difficult to distinguish from a moraine, but the material composing it is better sorted than a moraine and is layered. The origin of kamas, like eskers, is explained in different ways: these can be deposits of lakes that existed on the surface of a glacier or near its edge.
6. Vast areas are occupied by outwash (Il. sand - sand) - surfaces on which sands brought by melted glacial waters are common (Pripyat Polesie, Meshchera Lowland, etc.). Outwash has a characteristic landscape, but they are also not particularly perceived as landforms.
7. Lakes in glacial basins. Exaration occurs unevenly, because the rocks underlying the glacier are not equally stable. As a result, basins are formed, usually elongated in the direction of glacier movement. Most of the lakes of Karelia and Finland, as well as the Canadian Shield, are located in such basins. The basins of large lakes are tectonic troughs, but they also experienced glacial treatment. Thus, on the northern shores of Lakes Ladoga and especially Onega there are bays that are clearly of glacial origin, this can be seen if only because they extend from northwest to southeast, which is a common direction for Karelian lakes.
8. Ice moves in streams in mountain valleys, expanding and deepening them, forming trough-shaped valleys - troughs (German trog - trough).
9. Mountains where there is glaciation or there was one in the geologically recent past are characterized by steep ridges and sharp peaks; in the top parts there are kars (German kar), bowl-shaped niches with slopes that are steep in the upper parts and gentler below. Karas, or mountain cirques, are formed under the influence of frost weathering, serve as places for the accumulation of snow and the formation of glaciers. When adjacent punishments are connected by their side parts, a protrusion in the form of a three- or four-sided pyramid often remains between them. Karas and trogs can be seen not only in the mountains where there is modern glaciation. There are almost no glaciers in the mountains of Transbaikalia, but the solid crystalline rocks perfectly preserve the forms formed during the Quaternary glaciation.
Aeolian landforms
Barchans are a type of dunes, relief mobile formations of sand in deserts, blown by the wind and not fixed by plant roots. They reach a height of 0.5-100 m. The shape resembles a horseshoe or sickle. In cross section they have a long and gentle windward slope and a short, steep leeward slope.
Depending on the wind regime, clusters of dunes take different forms. For example, there are dune ridges stretched along the prevailing winds or their resultant; dune chains transverse to mutually opposite winds; dune pyramids in places of convection of vortex flows, etc.
Without being fixed, dunes under the influence of winds can change shape and mix at a speed of several centimeters to hundreds of meters per year.
Thermal landforms in our country are represented mainly by frost weathering.
1. Frost heaving is characteristic of different regions of the cold belt, although it is unevenly developed due to local characteristics of the composition, structure and properties of rocks. Small heaving mounds may arise directly from the increase in the volume of freezing water in the pound. But migration mounds have large values when new volumes of water migrate to the freezing front from the underlying thawed part of the soil, which is accompanied by intense segregated ice formation. This is often associated with peat bogs, to which, when freezing, moisture migrates from rocks with much higher humidity. Such mounds were observed in Western Siberia.
2. In such a cold climate, small-polygonal structural forms are also developed, associated with cracking of the soil into small polygons, uneven freezing of the seasonally thawed layer and the development of stresses and often ruptures in closed systems. Among such small-polygonal structures one can name medallion spots. When freezing occurs from above and along cracks inside the landfill, hydrostatic pressure is created, the liquefied soil of the upper permafrost crust breaks through and spreads over the surface. The second type of polygonal structural forms are stone rings and polygons. This occurs in loose rocks of heterogeneous composition, containing inclusions of stone fragments (crushed stone, pebbles, boulders). As a result of repeated freezing and thawing, large clastic material is pushed out of the rock to the surface and moves towards crack zones, with the formation of stone borders.
3. Slope processes in areas of permafrost development include two types: solifluction and kurums (stone flows). Solifluction refers to the slow flow of loose, highly waterlogged dispersed sediments along the slopes. During the seasonal thawing of ice-saturated dispersed pounds of the seasonally thawed layer, they become heavily waterlogged with melt and rainwater, lose their structural connections, transform into a viscoplastic state and slowly move down the slope. In this way, sinter forms in the form of tongues or terraces are formed. Kurums are mobile stone placers in the mountains and plateaus of Eastern Siberia and other areas where rocks come close to the surface. The formation of clastic material in kurums is associated with frost weathering during periodic seasonal freezing and thawing and other processes. Kurums in some places form continuous stone fields (ranging in size from a few hundred square meters to several tens of square kilometers).
4. One of the most famous examples of permafrost degradation is thermokarst. This name was given to the process of thawing underground ice, accompanied by subsidence of the earth's surface, the formation of depressions and shallow thermokarst lakes.
Natural phenomena
Open your textbooks, find a map of the latest tectonic movements (according to R.: Fig. 26 on p. 26; according to B.: Fig. 22 on p. 46).
The latest tectonic movements → earthquakes, volcanism.
(To create an image of natural phenomena, you can show the video “Natural Phenomena.”)
Consider the structure of the landslide (according to R.: p. 72; according to B.: Fig. 27 on p. 51).
Reason: gravity → landslides, avalanches, mudflows
What natural disasters are possible in your area? How to protect yourself from dangerous phenomena?
Homework
1. According to R.: § 12, 13.
2. Draw on the contour map the relief forms formed under the influence of external factors. To do this, come up with and write down symbols for these landforms in the map legend.
Additional material
Plains of Russia
Name |
Geographical position |
Landform |
Predominant heights, m |
Maximum height, m |
Valdai |
Eastern Europe |
Elevation |
||
Privolzhskaya |
Elevation |
|||
Northern Uvaly |
Elevation |
|||
Smolensk-Moscow |
Elevation |
|||
Central Russian |
Elevation |
|||
Caspian |
Flat lowland |
|||
West Siberian |
Flat lowland |
|||
Sibirskie Uvaly |
North of Western Siberia |
Elevation |
||
North Siberian |
Eastern Siberia |
Hilly lowlands |
||
Central Siberian |
Plateau |
|||
Vitimskoe |
Mountain belt of Southern Siberia |
Plateau |
||
Yano-Indigirskaya |
Northeast Siberia |
Lowland |
||
Kolyma |
Lowland |
Mountains of Russia
Name |
Geographical position |
Highest peak, m |
||
Ural |
East of the Russian Plain |
Hercynian folding |
Mount Narodnaya, 1895 |
|
Mountain belt of southern Siberia |
Mount Belukha, 4506 |
|||
Western Sayan |
Caledonian, Hercynian folds |
Mount Kyzyl-Taiga, 3121 |
||
Eastern Sayan |
Mount Munsu-Sardyk, 3491 |
|||
South of the Russian Plain |
Alpine orogeny |
Mount Elbrus, 5642; Mount Kazbek, 5033; Mount Dykhtau, 5204 |
||
Sikhote-Alin |
Primorye |
Mesozoic folding |
Mount Tordoki-Yani, 2077 |
|
Chersky Ridge |
Northeast Siberia |
Mesozoic folding |
Mount Pobeda, 3147 |
- Mesozoic folding (in English literature - Cimmerian) is the era of folding, in which many mountain ranges appeared, which are now located in Central Asia.
Related concepts
The Atlantic (Greek Ατλαντικα) is a hypothetical ancient continent that formed in the Proterozoic about 2 billion years ago from various platforms located in the territory of modern West Africa and Eastern South America. The name was proposed by Rogers in 1996 and comes from the Atlantic Ocean that now passes through the old continent. (from the Latin name of Scotland - Caledonia, Caledonia) - an era of tectogenesis, expressed in a combination of geological processes (intense folding, mountain building and granitoid magmatism) at the end of the early - beginning of the middle Paleozoic (500-400 million years). It completed the development of geosynclinal systems that existed from the end of the Proterozoic - the beginning of the Paleozoic, and led to the emergence of folded mountain systems - the Caledonides. The term was introduced by the French geologist M. Bertrand in 1887.
Sections: Geography
Purpose and objectives of the lesson: Continue to form in students an understanding of the peculiarities of the patterns of relief formation and its modern development - the influence of internal and external factors using the example of the Belgorod region. Show the continuity of relief development. To develop the ability to work with maps (tectonic, geological), tables. Talk about the influence of humans on the relief.
Equipment: Physical, tectonic, geological map of Russia and the Belgorod region; geochronological table.
During the classes
I. Organizational moment.
II. Repetition. Checking homework.
Working with cards. Test tasks.
Option 1 |
Option 2 |
| 1. Stable areas of the earth’s crust are called: a) platforms; b) shields; c) folded areas. |
1. The most ancient geological era is called: a) Proterozoic; b) Paleozoic; c) Archean. |
| 2. The plains are located on: a) boundaries of lithospheric plates; b) platforms; c) in folded areas. |
2. The geological era in which we live now is called: a) Mesozoic; b) Cenozoic; c) Paleozoic. |
| 3. Mountains are located on: a) platforms; b) slabs; c) in folded areas. |
3. Which peak corresponds to the Caucasus mountain system? a) Pobeda; b) Belukha; c) Narodnaya; d) Elbrus. |
| 4. The following ridges rose into the Mesozoic folding: a) Altai; b) Sikhote-Alin; c) Caucasus. |
4. Which mountain ranges belong to the Alpine folding? a) Ural; b) Caucasus; c) Altai. |
| 5. Deposits are confined to ancient folded areas: a) coal, oil, gas; b) iron ores, gold. |
5. Which mountains are younger? a) Chersky ridge; b) Caucasian. |
| 6. What is the highest mountain in Russia? a) Folk; b) Elbrus; c) Belukha; d) Victory. |
6. What mountain system does the height of 1896m correspond to? a) Folk; b) Elbrus; c) Belukha; d) Victory. |
| 7. What era of new life are we living in? a) Mesozoic; b) Cenozoic; c) Proterozoic. |
7.The most ancient mountain formation? a) Hercynian; b) Proterozoic; c) Archean. |
Answers: Option 1: 1-a; 2-b; 3-in; 4-b; 5 B; 6-b; 7-b. Option 2: 1-a; 2-b; 3-g; 4-b; 5 B; 6-a; 7-in.
III. Learning new material.
- Look at the blackboard. We will look at these terms in today's lesson.
Erosion, landslides, karst, suffusion phenomena, aeolian processes, technogenic relief.
1. Working with the textbook “Geography of the Belgorod Region” part 1. (make notes in a notebook while working)
- Using Fig. 2 p. 5 of the textbook, answer - what major landform lies at the base of the Belgorod region?
- What tectonic structure is located at the base of the East European Plain?
- What is the name of the projection of the crystalline basement in the Belgorod region? (Voronezh massif).
- How is the Voronezh anteclise, a large tectonic uplift, expressed in relief? (Central Russian Upland).
- Using Fig. 3. Geochronological table and fig. 4. map of the geological structure of the Belgorod region, determine what rocks represent the sedimentary cover? (Rocks of the Cenozoic and Mesozoic eras)
- Where in the region do chalk deposits predominate? (Along the river valleys and in the eastern part of the region).
- According to Fig. 5 page 7 determine what is the thickness of rocks of various systems, deposits, formations?
- Why does the earth's surface in the region have a general slope in the southern and southwestern direction? (The north-eastern part of the region is confined to the arched (elevated) part of the Voronezh massif, and the rest of the territory is located on its southwestern and southern slopes.
- What rocks are associated with terrestrial magnetic anomalies in the region? (The upper part of the crystalline massif represents a series of narrow ridges consisting of layers of ferruginous quartzites (Stary Oskol)).
2. Work according to Fig. 6. with a map of mineral resources of the Belgorod region. Exercise. Answer the questions:
- What mineral resources are represented on the map of the Belgorod region?
- What is the leading mineral resource for the region?
- What iron ore areas can you name?
3. Teacher information about iron ores in the Belgorod region.
On the state balance sheet according to B.o. as of 01/01/1998 there were 14 deposits with balance iron ore reserves of 52.2 billion tons, or 51% of Russia's reserves. Ores are rich or poor in pure iron content. The main reserves of rich iron ore (97.6%) with an iron content of 67-69% are concentrated in the Belgorod iron ore region.
Low-grade iron ores (34.6% - total iron content - ferruginous quartzites) have been explored in the Oskol basin.
The share in iron ore production is 40% of the Russian one. Currently, two mining and processing plants (Lebedinsky, Stoilensky), the KMAruda plant operate on the raw material base of iron ores, and the Yakovlevsky mine for the extraction and processing of KMA iron ores is being built.
The Lebedinskoye iron ore deposit (Fig. on page 10) is one of the unique ones in the KMA basin. Thanks to its huge reserves (22.4 billion tons) and the quality of the ore (no harmful impurities), it is included in the Guinness Book of Records. At the current pace of development of the deposit by Lebedinsky GOK, it will ensure uninterrupted, sustainable operation of the plant for a period of more than 500 years. The Lebedinsky quarry is a huge man-made bowl on the surface of the Earth, which is visible from space orbital stations. Its dimensions: surface length 5000 m, width – 3500 m, depth more than 300 m.
(Physical education pause)
4. Conversation with students.
— As a result of what processes is the relief formed? (internal - endogenous and external - exogenous processes)
Endogenous or internal processes are called newest, which on platforms manifest themselves in secular slow fluctuations of the earth's crust at a speed of 1 cm per year.
Exogenous processes occur under the influence of flowing waters (rivers, mudflows, glaciers), wind, and permafrost.
— What processes are decisive in the formation of the modern relief of the Belgorod region? (exogenous)
Exogenous processes:
- flowing waters(form river valleys, ravines, hollows);
- wind(aeolian - dunes, hilly sands);
- Human(quarries, waste heaps).
The main features of the modern relief of the Belgorod region (Fig. 7. p. 14 Relief of the Belgorod region) began to be created at the end of the Neogene period, after it was freed from the Neogene sea - the last one that covered its territory. The region occupies part of the southern slope of the Central Russian Upland and is an erosion-denudation plain with average heights of about 200 m, dissected by a valley and a ravine-gully network. The maximum elevation of the relief is 276 m on the watershed of the Donetsk Seimitsa, Seim and Korocha rivers. The total length of the gully-beam network on the territory of B.O. about 50 thousand km, which is comparable in length to the length of the equator.
The natural processes that shape the relief on the territory of B.O. are quite diverse. The most common are linear erosion, landslides, karst, suffusion phenomena, aeolian processes, and technogenic relief.
5. Working with the textbook. Find explanations of natural processes in the text on pages 15-16. Read it out loud.
IV. Consolidation.
Students prepare questions for each other on the topic of the lesson and ask them.
V. Homework assignment.
VI. Reflection.
Literature: Geography of the Belgorod region: Textbook. manual for students in grades 8–9 of secondary schools: In 2 parts. Part one. Nature - M.: Moscow State University Publishing House, 2006. - 72 p.
The entire modern relief of both Russia and the whole world began to form a very long time ago, at the dawn of the geological history of the Earth. The above also applies to the folding of the planet - mountain ranges, depressions. It was formed over many geological eras, and continues to change its appearance even now. In this article we would like to focus your attention on the Cenozoic folding - the “youngest”. And let's start with a general analysis of geological eras.
What are the types of folds?
The topography of our planet is historically heterogeneous - some objects were formed earlier, others millions of years later. Accordingly, all existing folds are named after the era in which they acquired their appearance. Let's get to know them briefly.
Archean folding. The oldest one is 1.6 billion years old. Basically, it includes platforms - the peculiar “cores” of the continents, their most stable and level areas.
Baikal folding. Age - 1200-500 million years. It got its name from the name of a Russian lake, since the area where it is located was formed during this period. The Baikal region also includes the Brazilian Peninsula, the Patom Highlands, etc.
Caledonian folding. Formed 500-400 million years ago. Named after about. Caledonia, where it was first discovered by geologists. Great Britain, eastern Australia, Scandinavia, southern China were formed during this era.
Hercynian folding. Relief formed 400-230 million ago. Here we include the Urals, most of Europe, the Great Dividing Range, the Cape Mountains, and the Appalachians.
Mesozoic folding. Age - 65-160 million years. It was formed when dinosaurs reigned on Earth. The Russian Far East and the Cordilleras appeared precisely then.
The last to take shape was the Alpine or Cenozoic folding. Let's talk more about her era.
Cenozoic - what is it?
Cenozoic - the Cenozoic era - is the geological era in which we live today. And it began 66 million years ago. Its border was marked by the mass extinction of biological species, which began at the end of the Cretaceous period.
This name was first used in 1861 by John Phillips, an English geologist. Its short designation, which you can find in the scientific literature, is KZ. The word is formed from the merger of two ancient Greek words: καινός ("new") + ζωή ("life"). Accordingly, “new life”.
The Cenozoic itself is divided within itself into several more periods:
- Paleogene (65.5-23.03 million years ago). Includes:
- Paleocene;
- Eocene;
- Oligocene
- Neogene (23.03-2.59 million years ago). Consists of two stages:
- Miocene;
- Pliocene
- Quaternary period. It began 2.59 million years ago and continues to this day. So far, scientists have identified only two eras within it - the Pleistocene and Holocene.
What is remarkable about the Cenozoic era?
What significant happened for geological history during the Cenozoic era? The following events are highlighted:
- Separation of New Guinea and Australia from Gondwana.
- The approach of the above-mentioned massifs to Southeast Asia.
- Establishment of Antarctica at the South Pole.
- Expansion of the Atlantic Ocean.
- Continuation of continental drift, the adjoining of North America to South America.
Transformations in the biological world also turned out to be significant:
- All animals larger than a crocodile have disappeared from the face of the Earth.
- As a result of continental drift, unique biological communities were formed on the continents.
- The advent of the era of mammals and angiosperms.
- The era of savannas, insects, flowering plants.
- The emergence of a new biospecies - Homo sapiens.
What is this - Cenozoic folding?
As we said, at present geologists agree that the Alpine-Himalayan belt is quite complexly constructed. Its development continues in our era - it is at the orogenic stage. For people, this is dangerous due to increased seismic activity and volcanic eruptions, which leads to the destruction of structures, settlements, and human casualties.
Cenozoic regions in the Russian Far East
Now let's look at the specifics of the mountains of the Cenozoic folding in the Far East. As for the West Kamchatka system, it is a terrigenous complex of the Upper Cretaceous. It is covered by Paleogene and Neogene rocks.
The Central and Eastern Kamchatka systems formed in the Paleogene. But large basalt volcanoes in this area appeared in the Pliocene-Pleistocene era. What’s interesting: The Eastern zone is still actively being formed today due to modern volcanism (28 active volcanoes).
The Kuril island arc (Big and Small ridges) was formed in the Cretaceous and is crushed by transverse grabens (faults, downed areas of the terrain). A deep-sea trench is located in front of the arc front.
And finally, the Cenozoic folding of Sakhalin. It is divided into western and eastern parts by the Central Kuril Graben. Sakhalin is rich in coal deposits, gas and oil deposits.
So we presented the mountain systems of the areas of Cenozoic folding, along which are the regions of Russia - the Caucasus and the Far East. This geological zone is the youngest. Moreover, it is still being formed: for example, these processes are very noticeable in Kamchatka. However, they are accompanied by earthquakes and volcanism that are dangerous for people.