Topic: "Development of landforms". Terms (concepts): Endogenous processes Exogenous processes Volcanism Earthquakes Recent tectonic movements Glaciation. Geography presentation "development of landforms"

It would seem that all processes for the formation of the Earth's landscapes have long been completed: there are high mountains and deep depressions, plains, lowlands, hills. However, even today there is a continuous development of landforms. Under the influence of internal and external forces appearance the globe continues to undergo changes.

relief formation

The modern relief is changing all the time: there is a continuous process of destruction, displacement and accumulation rocks leading to the formation of new landscape forms.

All processes affecting the formation of relief are divided into two large groups: internal (endogenous) and external (exogenous).

Endogenous processes are the latest tectonic processes occurring in the bowels of the earth. They're in equally appear both in the mountains and on the plains.

Where the earth's crust, due to its antiquity, has lost its former plasticity, the rocks can no longer bend in the form of folds. As a result, powerful faults and faults are formed under the influence of tectonic movements, which dismember the land into huge blocks.

Development of landforms in Russia

Formation of relief on the territory modern Russia originates from the Quaternary period. At this time, the vast majority of land on the planet was covered with glaciers. The centers of glaciation were the Central Siberian Plateau, the Taimyr Peninsula and the current Ural mountains.

Rice. 3. Taimyr Peninsula.

Over time, when the glaciers began their gradual conquest of the south, layers of clay, gravel, and sand began to move after them. However, in the southern regions, under the influence of heat, the glaciers began to melt rapidly. This led to the subsidence of loose rocks and the formation of a moraine relief. This type of relief prevails, for example, in the Smolensk and Moscow regions.

The water formed after the melting of glaciers filled the depressions in the rocks, which, in turn, led to the formation of lakes in the northern part of the Russian Plain.

Endogenous processes are called neotectonic or recent. They can manifest themselves both in the mountains and on the plains Endogenous processes (recent tectonic movements) In folded areas: the revival of mountains, volcano mountains, grabens, horsts, intermountain basins On platforms: secular slow oscillations earth's crust

The latest movements In the Neogene-Quaternary, almost the entire territory of our country experienced uplift, except for the northern outskirts of the Asian part, the central regions West Siberian Plain and the Caspian lowland. The most active movements of the earth's crust are in the mountains. In the Caucasus, their speed is 5-8 cm per year. In young mountains, where the earth's crust is plastic, folds form.

Exogenous processes are processes that occur under the influence of flowing waters (rivers, glaciers, mudflows), permafrost, and wind. Exogenous factors Glaciation Moraines Outland plains “Sheep foreheads” lakes Flowing waters River valleys Ravines troughs Wind Aeolian landforms (dunes, dunes) Man Quarries Waste heaps tunnels

Ancient (Quaternary) glaciation Centers - the cities of Scandinavia, the Polar Urals, the Putorana Plateau and the city of Byrranga. From here, the ice spread to other territories. The result of the activity of the glacier was rounded rocks - "ram's foreheads", moraines, outwash plains, numerous lakes.

Conclusion Thus, the formation and development of landforms is the result of the joint action of internal and external forces and processes. They act as a unity of opposites. Internal processes are creative - they form large landforms: plains, mountains. External processes are destructive, they form smaller forms: river valleys, ravines, etc.

Literature Barinova I.I. Nature. Grade 8: Textbook - M .: Bustard, 2002 Zhizina E.A. Lesson developments in geography: Nature of Russia: Grade 8. - M .: "VAKO", Electronic textbook: Geography. Russia. nature and population. Grade 8, - M., 2004 Electronic encyclopedia of the Perm region, 2000.

Lesson 9

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Tasks: to form an idea of the interaction of internal and external processes as a source of relief development; to acquaint with the features of the formation of the relief on the territory of Russia in general and the Volgograd region in particular; show the impact of society on changing the surface of the Earth.

During the classes

I. Testing knowledge and skills on the topic "Mineral resources of Russia".

Possible verification options:

1. Individual writing Verification work. Students receive cards with glued parts contour maps individual regions and given tasks for them. It is possible to propose the contours of Western Siberia, the Central Siberian Plateau, the East European Plain, the Ural Mountains. Tasks - name the tectonic structure, its age, landform, height, mineral deposits, explain their origin.

2. Individual survey:

1) Tell us about minerals and their relationship with the tectonic structure of the territory.

2) Tell us about the minerals associated with platforms and folded areas.

3) Give an assessment of the mineral resource base of Russia.

4) Tell us about the rational use of mineral resources and the protection of subsoil.

5) Describe the environmental problems associated with mining.

3. Frontal conversation is conducted on the main questions of the previous lesson:

1) What are minerals?

2) What is a deposit?

3) What is a swimming pool?

4) What determines the location of certain mineral deposits?

5) What minerals is Russia rich in?

6) Not far from the Arctic Circle, in Vorkuta and Ukhta, we mine coal and gas. What does their presence in the area mean? How has the nature of this territory changed since the formation of oil and coal?

7) What research methods are currently used by geologists?

8) Name the largest coal and oil and gas fields in Russia.

9) Where is iron ore mined in the East European Plain? What tectonic structure are these deposits associated with?

10) What measures should be taken to conserve minerals?

11) Can dirt be a mineral? Why?

12) What mineral does the teacher use when explaining new material? How was this mineral formed?

13) What is the classification of minerals?

4. Verification of the nomenclature of mineral pools.

Students must fill in the gaps in the table:

The study new topic involves the development and concretization of knowledge about the action of internal and external relief-forming processes. Therefore, during the introductory conversation, it is necessary to update the information received by schoolchildren in the process of studying geography courses in grades 6 and 7. The teacher organizes a conversation, as a result of which he finds out what the students know about the change in relief. Based on the knowledge of the students, the teacher builds his subsequent lecture.

This stage of the lesson is conducted in the form of a lecture. The teacher accompanies his story with a demonstration of paintings and illustrations of various forms of relief. For better assimilation of the material, it is necessary to consolidate it during the lecture. Questions and assignments are given in section IV. The result of the lecture is the compilation of a table by students in notebooks, which indicates the relief-forming factors and the relief forms they create. The teacher needs to get the students to understand keywords, it is also desirable to write them down in a notebook during the lecture.

1. The relief of the earth's surface is formed under the influence of processes that can be divided into two groups:

I. internal or endogenous(from the Greek endon - inside and genes - giving birth, born). Their source is thermal, chemical, radioactive energy bowels of the earth. Endogenous processes manifest themselves in the form of mountain-building movements, the intrusion of magma into the earth's crust, its outpouring to the surface, slow fluctuations of the earth's crust, etc. Landforms that are created mainly by endogenous processes are called endogenous.

II. External, or exogenous(from the Greek echo - outside, outside). They flow almost exclusively due to solar energy coming to Earth. Landforms created as a result of these processes are called exogenous. To external processes often include anthropogenic factors, but they can also be distinguished into a separate group.

Landforms are created due to the interaction of endogenous and exogenous processes, but in most cases it is possible to single out the leading process belonging to one or another group. The larger the relief form, the greater the role of endogenous processes in its formation. Exogenous processes create details, small forms, to which mountains and plains owe their originality and diversity. Endogenous and exogenous processes operate continuously and simultaneously; at some time, some may be more pronounced, at another period, others, but the action of both groups of processes does not stop.

2. Endogenous landforms are created as a result of movements of the earth's crust. We are used to believing that we ourselves are moving along the motionless surface of the Earth. But for the Earth to move - no, not like a planet around the Sun, but like the soil under our feet ... Well, except perhaps in separate places and occasionally - during earthquakes, landslides or explosions. But now we will not talk about that. That same unshakable Earth, or rather the earth's crust, oscillates and moves everywhere and always. Only we notice it rarely or not at all. Literally every point of the earth's crust moves: rises up or falls down, shifts forward, backward, right or left relative to other points. Their joint movements lead to the fact that somewhere the earth's crust slowly rises, somewhere it sinks. These slow movements went unnoticed until late XVIII century. The well-known Swedish physicist and astronomer Anders Celsius laid the foundation for the study of modern movements of the earth's crust (we still use the 100-degree temperature scale proposed by him). He made notches on the coastal rocks of the Scandinavian Peninsula to study the mutual movements of land and sea. It soon became clear that the serifs were getting higher and higher above mean sea level. The scientist believed that the matter was in the lowering of the sea level. But later it turned out that the reason was the rise of land. Since the Celsius experiment, 250 years have passed, during which time scientists have solved many questions. For example, it was found that Northern Europe (Scandinavian, Kola Peninsula, Finland, Karelia) rises from the surrounding seas at a rate of up to 1 cm per year. But the territory of Denmark and the Netherlands, on the contrary, is lowered. Already, about 1/3 of the Netherlands is below sea level. The Lower Volga region is also experiencing uplifts, because earlier these areas were occupied by the sea. mountain systems also experience uplifts. Despite the fact that rocks have great strength and hardness, they can be crumpled into folds and torn apart by tectonic faults, as well as broken by cracks. For example, Lake Baikal is located in a graben. The graben is a parallel system of faults that delineate a depression. The greatest depth of the lake reaches 1620 m. Slow movements of the earth's crust often proceed imperceptibly: stresses slowly increase, layers of rocks slowly deform, crumpling into folds, displacement along ruptures slowly occurs, and only sometimes this movement, like an explosion, occurs in seconds. Then the earth shakes. A strong earthquake can produce significant changes in the earth's surface. Along the faults of the earth's crust, its blocks are displaced, and where there used to be a flat place, a cliff appears. Rockfalls and landslides occur in the mountains.

3. Landforms created by exogenous processes.

On elevated areas of the earth's surface, the destruction of rocks occurs. Then, the direct action of gravity, water, wind, ice transfer crushed, destroyed rocks to lower areas of the surface, where they are deposited. The demolition of rock particles from elevated areas is called denudation (from Latin denudation - exposure). The deposition of rock is accumulation (from Latin accumulatio - gathering in a heap, accumulation). The rate of denudation depends on which rocks are destroyed and demolished. Sedimentary rocks are usually destroyed more easily, igneous and metamorphic rocks are more stable. Denudation reduces high areas of the earth's surface, accumulation increases low ones, thus reducing the overall elevation difference.

Exogenous processes begin with the preparation of rocks for transfer, with their destruction. All processes of destruction are called weathering. It occurs under the action of sunlight, water, air, organisms.

1) slope processes. The essence of these processes is that under the action of gravity - with or without water - the rocks that make up the slope are demolished from its upper part to the foot, where they are deposited. At the same time, the slope gradually becomes flatter. The steeper the slope, the stronger the slope processes. Slope processes accompany any type of exogenous processes and many types of endogenous ones and are so closely related to them that they seem to be part of these processes. The falling or rolling of small debris (sand, gravel) is called shedding. If large debris falls or rolls down, it is a rockfall; when a large mass of rock descends along the slope, which is crushed and mixed in the process of movement, this is a collapse. Large landslides can move huge amounts of rock. So, in 1911, in the Pamirs, the famous Usoi collapse occurred as a result of an earthquake, which created a dam in the river valley, above which Sarez Lake was formed. The weight of the collapse amounted to 7 billion tons.

2) Landforms created by flowing waters.mi. flowing water

The most active factor in the transfer of rock particles. The erosion of rocks by flowing water is called erosion (from Latin erosio

Erosion), and the landforms formed by this process are erosional. These will include ravines, ravines, river valleys. A ravine is a steep rut on a hill formed by melt and rain water, i.e., a temporary watercourse. The length of the ravine can reach several kilometers, the depth - several tens of meters, the width - tens, sometimes hundreds of meters. The ravines are gradually growing, their upper reaches are moving further and further. They do great harm agriculture, dismembering and destroying fields. The sites are dissected by ravines to such an extent that the slopes of neighboring ravines intersect and become unsuitable for any use. They are called badlands, badlands. The fight against ravines is carried out by fixing their slopes with forest plantations. The old, no longer growing ravine turns into a beam; the beam is wider than the ravine, its slopes are more gentle, they are overgrown with grass, sometimes shrubs or forests. Permanent streams - streams and rivers - flow in the valleys developed by flowing water together with slope processes. In terms of relief, the valleys of mountain and lowland rivers differ sharply. valleys mountain rivers narrow, steeply sloping, deeply incised. The valleys of lowland rivers are wide (up to tens of kilometers), their depth is small, and the slopes are gentle. Landforms created by flowing waters are widespread in some areas, such as the Volgograd region.

3) Landforms, created by groundwater. Travel speed groundwater small, so they affect the relief mostly not mechanically, but by dissolving the rutting rocks. Limestones are dissolving rock salt, gypsum and some other rocks. Dissolving the rock, water forms cavities, caves, dips, etc. This process is called karst, and landforms are called karst. The caves are complex systems passages and halls, the length can reach several kilometers. In Russia, the Kungur cave in the Urals is widely known. Funnels are a frequent form of karst relief - closed depressions of a conical, bowl-shaped shape with a diameter of several meters. They are found in the south of the Volgograd region in the Volga region.

4) Landforms created by glaciers. Most of the work of moving rock fragments is done by glaciers - natural ice accumulations in places where low temperatures prevail. Glaciers move under the force of gravity because ice is plastic and can flow slowly. The rock fragments carried by the glacier and eventually deposited by it are called moraine. Mountain glaciers are located in near-top bowl-shaped niches - kars. When the glacier moves down the mountain valley, it expands and deepens it, forming a trough-shaped valley - a trough. In lower places, where it is warmer, the glacier melts, and the moraine brought by it remains. Cover glaciation captures not only mountainous regions, but also vast areas on the plains. In the Quaternary period, several ice sheets arose. Their centers in Russia were located on the Kola Peninsula, the Polar Urals, the Putorana Plateau, and the Byrranga Mountains. As the climate became warmer, the glaciers became shorter and gradually disappeared altogether. In areas where glaciers deposited material, large areas remained, occupied by hilly moraine relief. This type of relief prevails on the Valdai and Smolensk-Moscow uplands of the Russian Plain. The last glaciation reached the Volgograd region.

5) Landforms in areas with a dry climate. The relief of areas with insufficient moisture - deserts and semi-deserts - is usually primarily associated with the action of the wind. The relief forms formed as a result of the action of the wind are called aeolian - after the ancient Greek wind god Aeolus. The simplest eolian forms are blowout basins. These are depressions formed in those places where small particles are carried by the wind from the surface, not protected by vegetation. The bottom of the basin is strewn with pebbles, rubble and boulders. Dunes are common in deserts. This accumulation of free-flowing sand, blown by the wind, is from a meter to 100-150 m high. The dune has the shape of a crescent in plan, with its convex side turned towards the wind.

6) Coastal landforms. Peculiar landforms are created on the shores of the seas and large lakes. Almost all of them are related to geological structure coast, with the activity of sea or lake waves. On fairly steep banks, a cliff is most often formed - a vertical or almost vertical ledge. Beaches are formed near the gently sloping shores - accumulations of marine sediments.

7) Landforms in areas of permafrost distribution. Permafrost affects the relief, as water and ice have different density, as a result of which freezing and thawing rocks undergo deformation. The most common type of frozen soil deformation is heaving associated with an increase in the volume of water during freezing. The relief forms that arise in this case are called heaving mounds; their height is usually no more than 2 m. In the course of layer-by-layer freezing, ground and river ice is formed. Giant icings up to 20 km2 are known. Ice thickness varies from a few to 500 m.

8) Landforms created by living organisms. On land, such forms are usually small. These are marsh hummocks, marmots, in tropical countries - termite mounds. Marmots and ground squirrels can often be found in the steppes of the Volga region. In the temperate zone large areas occupy swamps with peat ridges; the height of the ridges is small - usually 0.5 m, sometimes a little more, the ridges can be extended for hundreds of meters and for kilometers. The role of living organisms on the shores of the seas is incomparably greater. Reef-building organisms actively manifest themselves in the tropical zone, the result of which are coral reefs.

9) Landforms created by man. A person can transform the relief of the earth's surface directly (making an embankment, digging a foundation pit) or by influencing the natural processes of relief formation - accelerating or slowing them down. Landforms created by man are called anthropogenic (from the Greek anthropos - man and genes - giving birth, born). The direct impact of man on the relief is most pronounced in the areas of mining. Underground mining is accompanied by the removal to the surface of a large amount of waste rock and the formation of dumps having a conical shape - waste heaps. Numerous waste heaps create a characteristic landscape of coal-mining areas. At open pit mining minerals are created quarries - extensive depressions formed by digging. Significant changes in the relief are made during transport, industrial and civil construction. Sites are leveled for structures, embankments and excavations are created for roads. The indirect influence of man on the relief was first felt in agricultural areas. felling forests and plowing of slopes create conditions for the rapid growth of ravines. The construction of buildings and engineering structures contributes to the occurrence or intensification of landslides.

relief-forming factor	Created landforms
I. Endogenous: 1.Mountain building movements. 2.The intrusion of magma into the earth's crust. 3.outpouring of magma to the surface. 4.Folding. 5.Tears and deformations	1. Large landforms
II. Exogenous: 1. Direct action of gravity	1.Scree. 2.Crash. 3.Landslide
2. Activity of flowing waters	1. Ravines. 2. Beams. 3. Bad lands. 4.River valleys
3. Glacier activity	1.Kary. 2.Trogs. 3.Hilly-morainic relief
4. Groundwater activity	1. Caves. 2. Funnels
5. Activity of sea and lake waves	1.Cliff (cliff). 2.Beach
6. Wind activity	1.Blowing pits. 2. Dunes, dunes. 3. Aeolian cities
7. Impact of permafrost	1. Bumps of heaving. 2.Thermokarst depressions
8. Activity of living organisms	1. Bog bumps. 2.Marmots. 3. Peat ridges. 4.Termite mounds. 5. Coral reefs
9. Human activities	1.Careers. 2. Dumps. 3. Waste heaps. 4. Mounds. 5. Notches. 6. Foundation pits. 7.Terraced slopes

IV. Fixing the material.

To increase the effectiveness of students' learning activities in the classroom, questions and tasks to consolidate the material must be used during the lecture.

1. According to Figure 17, determine in which regions of Russia the uplifts of the earth's crust in the Neogene-Quaternary time were the most intense. What tectonic structures are these areas confined to? By physical map determine what kind of relief was formed in these areas and what are its heights. Why are the Ural Mountains lower than Altai?

2. In what regions of Russia do slow subsidence occur? How will this affect the appearance of the earth's surface?

3. On the map "Earthquake distribution areas" trace in which areas the strongest earthquakes are observed. What is it connected with? Within which tectonic structures are earthquakes extremely rare? Why?

4. On the map "Ancient glaciation" determine the southern boundary of the spread of ice sheets. What areas of our country have experienced the greatest impact of the glacier? What forms of relief prevail in the center of glaciation, and which ones - in the more southern regions where the ice melted?

5. Consider whether mountainous or lowland areas are most characterized by erosional relief. Which rocks are most susceptible to erosion?

6. In what regions of Russia does the activity of flowing waters especially affect the relief, in which - the activity of the wind?

V. Summing up.

Homework:§ 8 to s. 52, learn keywords.