Plain - a piece of land, the slope of which does not exceed 50 o, and the heights do not differ by more than 200 meters. This is the most common type of relief on the planet, occupying about 64% of the territory. On the territory of the Russian Federation there are about 30 plains, the most famous of which is East European. In terms of area, it is second only to the Amazonian lowland and is the second in the world.

For Russia, the plains are of great importance, because almost 75% of the country is located on this type of terrain. Historically, it was on the flat areas that the Slavic civilization developed: ancient cities and roads, there were political upheavals and wars. The fertile soils of the plains not only provided people with food, but also brought unique features into culture and industry.

East European Plain (4 million km2)

One of the largest plains on the planet, covering most of of Eastern Europe, received a second name - Russian. The distance between the northern and southern borders exceeds 2500 km. And from west to east it stretches for 2700 km. Borders:

• In the northwest - the Scandinavian mountains;
• In the southwest - the mountains of Central Europe (Sudet);
• In the southeast - Caucasian mountains;
• In the west - the Vistula River;
• In the north - the White and Barents Seas;
• In the east - the Ural Mountains and Mugodzhary.

The height of the plain above sea level is not uniform. Frequently occurring hills are located at elevations of 200-300 m, and major rivers, such as the Volga, Dnieper, Danube, Don, Western Dvina and Vistula. The origin of the vast majority of uplands and lowlands is tectonic.

Two plates lie at the base of the plain: Russian with a Precambrian crystalline basement and Scythian with a Paleozoic folded basement. The relief does not express the inter-tile boundary.

Glaciation had a significant impact on the process of relief formation, especially changing the surface of the northern areas. The passage of the glacier gave rise to the formation of many lakes for which the area is famous. This is how the White, Chudskoye and Pskov lakes were formed. In the southern part, the activity of glaciation is weakly manifested due to erosion processes.

Central Siberian Plateau (about 3.5 million km2)

In the eastern part of Russia there is another largest flat area - the Central Siberian Plateau. It covers areas Irkutsk region, Krasnoyarsk Territory and Yakutia.

• On South - mountain system Eastern Sayan, as well as the mountainous regions of the Baikal and Transbaikalia;
• In the west - the valley of the Yenisei River;
• In the north - the North Siberian lowland;
• To the east is the valley of the Lena River.

The plateau is located on the Siberian platform. A characteristic feature is the alternating plateaus and ridges. the highest peak is Mount Stone (height 1701 m above zero), belonging to the middle mountains of Putorana. The western edge of the plateau is covered by dissected uplands of the Yenisei Ridge (the highest point is Mount Enashimsky Polkan 1104 m high). The territory of the Central Siberian Plateau is distinguished by the largest permafrost rocks in the world, the height of which reaches 1500 km.

West Siberian Plain (2.6 million km²)

The plain is located in the northern part of Asia and covers the entire territory of western Siberia. It has a characteristic trapezoidal shape, which narrows towards the north. The length from south to north is about 2500 km, and from west to east it varies from 800 to 1950 km. Borders:

• In the west - the Ural Mountains;
• In the east - the Central Siberian Plateau;
• In the north - the Kara Sea;
• In the south - the Kazakh uplands;
• In the southeast - West Siberian Plain and foothills of Altai.

The surface of the plain is relatively uniform with little elevation change. Low-lying areas are concentrated in the central and northern parts, and low elevations are located along the eastern, southern and western outskirts(height does not exceed 250 m).

Baraba lowland (117 thousand km2)

The Baraba stele is located in the southern part of Western Siberia, between the Irtysh and Ob rivers. It is an undulating plain, in the southern part of which manes (parallel elevations) are common. On the territory of the lowland are Novosibirsk and Omsk region. It is composed of thick deposits of Mesozoic and Cenozoic age.

In lower areas (height 80-100 m), fresh (Ubinskoye) and salty (Chany, Tandovo and Sartlan) lakes, swamps filled with peat moss and solonchak fields were formed. In the course of exploration activities in the north of the plain, deposits of oil and natural gas were discovered.

Kulunda Plain (100 thousand km²)

The Kuludin Plain is the southern part of the West Siberian Plain and covers the regions of Altai and the Pavlodar region. Its appearance is associated with the accumulative activity of large rivers - the Irtysh and the Ob. The southeast of the plain adjoins the Altai foothills. The highest point does not exceed 250 m, low-lying areas mainly occupy the central part (100-120 m above sea level).

The relief is distinguished by the alternation of elevated ridges (50-60m) and lowered areas separating them. The valleys of the rivers Burla, Kuchuk and Kulunda pass through the lowlands. For the industry of Western Siberia, the plain is of great importance due to the closed lakes, from which table and Glauber salt (Kuchukskoye and Kulunda lakes), as well as soda (Petukhovskie lakes) are extracted.

Azov-Kuban (Kuban-Azov lowland) plain (about 50 thousand km2)

The lowland is located in the Western part of the Ciscaucasia and covers the territory of the Krasnodar Territory, Stavropol Territory and the Rostov region. The height of the plain above sea level does not exceed 300 m.

• In the south - the Kuban River;
• In the west - the Sea of ​​Azov;
• In the east - the Kuma-Manych depression;
• In the north - the Yegorlyk River.

The main part of the plain is located within the Scythian plate. Rocks of Meso-Cenozoic age, mainly of sedimentary origin. The lowland area adjacent to the Black Sea is divided by a large number of branches of the Kuban River. In swampy areas of the plain, there are floodplains (flooded floodplains of rivers) and estuaries (bays that occur when a river flows into the sea).

A plain is a type of relief, which is a flat, vast area. More than two-thirds of Russia's territory is occupied by plains. They are characterized by a slight slope and slight fluctuations in the heights of the terrain. A similar relief is also found at the bottom of marine areas. The territory of the plains can be occupied by any: deserts, steppes, mixed forests, etc.

Map of the largest plains of Russia

Most of the country is located on a relatively flat type of terrain. Favorable allowed a person to engage in cattle breeding, build large settlements and roads. On the plains, it is easiest to conduct construction activities. Many minerals and others are concentrated on them, including, and.

Below are maps, characteristics and photos of landscapes of the largest plains in Russia.

the East European Plain

East European Plain on the map of Russia

The territory of the East European Plain is approximately 4 million km². The natural northern border is the White and Barents Seas, in the south of the land they are washed by the Azov and Caspian Seas. The Vistula River is considered the western border, and the Ural Mountains - the eastern.

At the base of the plain lies the Russian platform and the Scythian plate, the foundation is covered with sedimentary rocks. Where the base is raised, uplands were formed: Pridneprovskaya, Central Russian, Volga. In places where the foundation is deeply lowered, lowlands lie: Pechora, Black Sea, Caspian.

The territory is located in moderate latitude. Atlantic air masses penetrate the plain, bringing with them precipitation. The western part is warmer than the east. The minimum temperature in January is -14˚C. In summer, the air from the Arctic gives coolness. The largest rivers flow south. Short rivers, Onega, Northern Dvina, Pechora, are directed to the north. The Neman, Neva and Zapadnaya Dvina carry waters to the west. They all freeze over in the winter. Spring floods begin.

Half of the country's population lives on the East European Plain. Almost all woodlands are a secondary forest, a lot of fields and arable lands. There are many minerals on the territory.

West Siberian Plain

West Siberian Plain on the map of Russia

The area of ​​the plain is about 2.6 million km². Western border are the Ural Mountains, in the east the plain ends with the Central Siberian Plateau. The Kara Sea washes the northern part. The southern border is considered to be the Kazakh small sandbox.

At the base lies West Siberian plate, sedimentary rocks lie on the surface. The southern part is higher than the northern and central. The maximum height is 300 m. The edges of the plain are represented by the Ket-Tym, Kulunda, Ishim and Turin plains. In addition, there is the Nizhneeniseyskaya, Verkhnetazovskaya and North Sosvinskaya uplands. Siberian ridges - a complex of hills in the west of the plain.

The West Siberian Plain lies in three: arctic, subarctic and temperate. Due to the low pressure, arctic air penetrates the territory, cyclones are actively developing in the north. Precipitation is unevenly distributed, the maximum number falls on middle part. Most precipitation falls between May and October. Thunderstorms often occur in the southern strip in summer.

The rivers flow slowly, and many swamps have formed on the plain. All reservoirs have a flat character, they have a small slope. Tobol, Irtysh and Ob originate in mountainous areas, so their regime depends on the melting of ice in the mountains. Most reservoirs have northwest direction. In the spring comes a long flood.

Oil and gas are the main wealth of the plain. In total, there are more than five hundred deposits of combustible minerals. In addition to them, there are deposits of coal, ore and mercury in the bowels.

The steppe zone, located in the south of the plain, is almost completely plowed up. On the black soil there are fields of spring wheat. Plowing, which lasted for many years, led to the formation of erosion and dust storms. There are many salt lakes in the steppes, from which table salt and soda are extracted.

Central Siberian Plateau

Central Siberian Plateau on the map of Russia

The area of ​​the plateau is 3.5 million km². In the north it borders on the North Siberian Lowland. The Eastern Sayans are a natural border in the south. In the west, the lands originate from the Yenisei River, in the east they end at the Lena River valley.

At the heart of the plateau lies the Pacific lithospheric plate. Because of it, the earth's crust has risen significantly. The average heights are 500 m. The Putorana Plateau in the northwest reaches 1701 m in height. The Byrranga Mountains are located in Taimyr, their height exceeds a thousand meters. There are only two lowlands in Central Siberia: North Siberian and Central Yakut. There are many lakes here.

Most of the territories are located in the arctic and subarctic zones. The plateau is fenced off from the warm seas. Because of the high mountains, precipitation is unevenly distributed. They fall in large numbers in the summer. The earth is very cold in winter. The minimum January mark is -40˚C. Dry air and lack of winds help to endure such difficult conditions. Powerful anticyclones form during the cold season. There is little rainfall in winter. In summer, a cyclonic type of weather sets in. The average temperature during this period is +19˚C.

The largest rivers Yenisei, Angara, Lena, Khatanga flow through the lowland. They cross the faults of the earth's crust, so they have many thresholds and gorges. All rivers are navigable. Central Siberia has enormous hydropower resources. Most of the major rivers are located in the north.

Almost the entire territory is located in the zone. Forests are represented by larch species that shed their needles for the winter. Pine forests grow along the Lena and Angara valleys. In the tundra there are shrubs, lichens and mosses.

There are a lot of minerals in Siberia. There are deposits of ore, coal, oil. In the southeast are deposits of platinum. There are salt deposits in the Central Yakut lowland. There are deposits of graphite on the Nizhnyaya Tunguska and Kureika rivers. Diamond deposits are located in the northeast.

Due to difficult climatic conditions, large settlements are located only in the south. Economic activity human is focused on the mining and logging industry.

Azov-Kuban Plain

Azov-Kuban plain (Kuban-Azov lowland) on the map of Russia

The Azov-Kuban Plain is a continuation of the East European Plain, its area is 50 thousand km². The Kuban River is the southern border, and the northern one is the Yegorlyk River. In the east, the lowland ends with the Kuma-Manych depression, Western part goes to the Sea of ​​Azov.

The plain lies on the Scythian plate and is a virgin steppe. The maximum height is 150 m. Large rivers Chelbas, Beisug, Kuban flow in the central part of the plain, there is a group of karst lakes. The plain is located in the continental belt. Warm weather softens the local climate. In winter, the temperature rarely drops below -5˚C. In summer, the thermometer shows +25˚C.

The plain includes three lowlands: Prikubanskaya, Priazovskaya and Kuban-Priazovskaya. Rivers often flood settlements. On the territory there gas fields. The region is famous for its black earth fertile soils. Almost the entire territory is developed by man. People grow cereals. The diversity of flora is preserved only along the rivers and in the forests.

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Which is determined by the predominance plains. belongs to the most large forms relief - geotectures.

Geological dictionary: in 2 volumes. - M.: Nedra. Edited by K. N. Paffengolts et al.. 1978 .

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Ministry of Education of the Russian Federation

State educational institution of higher

vocational education

"Ural State Pedagogical University"

Faculty of Geography and Biology

Control work on geomorphology on the topic: "Features of relief formation within mountainous and lowland countries"

Performed:

Student 204 group

Unopened Yana

Yekaterinburg 2011

1. Introduction 3

2. Relief formation within mountainous countries 4

2.1 Classification of mountains according to structural features 6

3. Relief formation within the plain countries 8

3.1. Genetic types of plains 11

4. Conclusion 14

5. References 15

Annex 16

1. Introduction.

The main landforms of the Earth are mountains and plains. Mountains occupy about 40% of the earth's land, and plains - more than 60%.

Mountains are vast, highly elevated above the surrounding area, strongly and deeply dissected areas of the earth's crust with a folded or folded-block structure. The mountainous countries consist of individual mountain ranges and intermountain valleys and basins separating them.

Plains are vast areas of the earth's surface with small (up to 200 m) elevation fluctuations and slight slopes. In tectonic relationship, they correspond to more or less stable platforms that have not shown significant activity in recent times. 42% of the plains are located on ancient platforms.

The topic of relief formation is quite closely considered in universities, in geographical and geological specialties. In 6th grade this topic considered in the lessons "Mountains" and "Plains". And so throughout school course geography in lessons related to the topic "Relief".

The purpose of my work is to identify the features of relief formation within mountainous and lowland countries.

My job is to analyze literary sources, describe the process of formation of mountains, describe the process of formation of plains, identify the genetic types of plains and describe the process of their formation.

2. Relief formation within mountainous countries.

A mountainous country is a vast area of ​​the earth's surface with sharp fluctuations in elevation, significantly raised above the surrounding plains. Usually a mountainous country is formed as a result of a single stage tectonic development and consists of several mountain systems that differ in structure and appearance. Sometimes mountainous countries stretch for several thousand kilometers and have a complex configuration.

The highest mountains on Earth are folded or regenerated mountains. Many mountains were formed as medium-high or even low. The height of the rising mountains depends on the intensity of mountain building processes. Gradually disintegrating under the action exogenous processes, the mountains go down, and the higher they are, the more intense the destruction. If no new uplifts occur, high mountains turn into medium-altitude ones, and medium-altitude ones into low ones, and then a denudation plain appears in place of the mountains.

Mountains are divided into 3 groups according to their height:

-low(800 m above ocean level): Northern Urals, spurs of the Tien Shan, individual ranges of Transcaucasia;

- medium-altitude(up to 2000 m above sea level). They are characterized by smoothed, soft outlines of peaks, gentle slopes (mountains of the Middle Urals). They are covered with forests and do not rise above the snow line. Very rarely, these mountains have pointed peaks, a narrow jagged ridge (the Polar Urals, the Khibiny, the mountains of the island of Novaya Zemlya);

-high(more than 2000 m above sea level). Such mountains have steep slopes, their ridges are narrow, jagged. These are the mountains of Pamir, Tien Shan, Caucasus, Himalayas, Cordillera, Andes.

Mountains originate in orogenic-geosynclinal highly mobile zones of the earth's crust, otherwise in geosynclinal (folded) belts that stretch inside the continents and along their margins. In the first case, they are located between the ancient continental platforms, in the second case, between the platforms and the ocean floor. At the early stages of the development of these zones (geosynclinal stage), there is a subsidence and accumulation of thick strata of sedimentary, sedimentary-volcanogenic and igneous rocks.

Folded deformations also develop. Next comes a turning point in the development of the geosyncline, which is expressed in the transition to a general uplift of the zone, which enters the orogenic stage, i.e. mountain building stage. This stage coincides with the most intensive processes of folding and thrust formation, metamorphization of rocks, and ore formation. Geosynclinal troughs turn into folded (fold-block, fold-cover) mountain structures. Intermountain troughs are formed, and on the border with the platform - edge troughs. The troughs are filled with destruction products of growing mountains.

The process of mountain formation as a result of the development of geosynclines and the formation of folded structures occurred in different geological periods. The most ancient orogenic processes took place as early as the Archean time, covering vast expanses of modern continents. On the mainland of Eurasia, the regions of Archean folding occupy the spaces between the Yenisei and the Lena and most of the northern part of Europe.

But the current mountains, formed according to the scheme that is given, include only relatively young, Cenozoic, mountain uplifts. The older ones were leveled long ago by denudation processes and then raised again in the form of vaults and blocks by the latest tectonic movements. Arch and block, and most often arch-block uplifts led to the formation of revived mountains. They are as widespread as the mountains formed by the young, Cenozoic, folding.

2.1 Classification of mountains according to the features of the structure.

Fold mountains. These are primary uplifts during the bending of the earth's layers by tectonic movements, mainly in geosynclinal areas, in the ocean depths. In general, on land, folded mountains are a rare phenomenon, since when rising above sea level, rock folds lose their plasticity and begin to break, give cracks with displacements and disruption of the ideal folding of the successive and continuous alternation of synclines and anticlines. Typical folded mountains have survived only in separate areas in the Himalayas, Copenhagen, Dagestan, that is, in the mountains that arose in Alpine folding.

arched mountains. In many areas, land areas that have experienced tectonic uplift, under the influence of erosion processes, have acquired a mountainous appearance. Where the uplift took place on a relatively small area and had an arched character, arched mountains formed, a prime example which are the Black Hills in South Dakota, having a diameter of approx. 160 km. This area experienced arch uplift, and much of the sediment cover was removed by subsequent erosion and denudation. As a result, exposed central core, composed of igneous and metamorphic rocks. It is framed by ridges composed of more resistant sedimentary rocks, while the valleys between the ridges have been worked out in less resistant rocks.

Remaining mountains (plateau). Due to the action of erosion-denudation processes, mountain landscapes are formed on the site of any elevated territory. With the destruction of high plateaus, such as Colorado (in the southwestern United States), a highly dissected mountainous terrain is formed. The Colorado Plateau, hundreds of kilometers wide, was uplifted to a height of approx. 3000 m. Erosion-denudation processes have not yet managed to completely transform it into a mountain landscape, however, within some large canyons, for example grand canyon R. Colorado, mountains a few hundred meters high arose. These are erosional remnants that have not yet been denuded. As further development erosion processes, the plateau will acquire an increasingly pronounced mountainous appearance.

Blocky mountains (folded-blocky). This is the uplift of the earth's crust as a result of tectonic faults during repeated rises (movements) of ancient, destroyed mountain systems (reborn mountains). Blocky mountains often consist of layers of rocks crumpled into folds, have flat surfaces of peaks and steep rocky slopes of valleys.

volcanic mountains. There are different types. Volcanic cones, common in almost all regions of the globe, are formed by accumulations of lava and rock fragments erupted through long cylindrical vents by forces acting deep in the bowels of the Earth. illustrative examples volcanic cones - Mount Mayon in the Philippines, Fuji in Japan. Ash cones have similar structure, but not so high and composed mainly of volcanic slag - porous volcanic rock that looks like ash. Such cones are found near Lassen Peak in California and northeastern New Mexico. Shield volcanoes are formed by repeated outpourings of lava. They are usually not as tall and not as symmetrical as volcanic cones. There are many shield volcanoes in the Hawaiian and Aleutian Islands. In some areas, outbreaks volcanic eruptions were so close together that the igneous rocks formed entire ridges that connected the originally isolated volcanoes. This type includes the Absaroka Range in the eastern part yellowstone park in Wyoming. Chains of volcanoes meet in long narrow zones.

3. Relief formation within the plain countries.

A flat country is a vast territory on the earth's surface, the geomorphological appearance of which is determined by the predominance of plains. It belongs to the largest landforms - geotectures.

The relief of the plains is not very diverse. This is due to the homogeneity geological structure platform sections continental crust and their low mobility. The significant uplift of some platform plains (for example, in Eastern Siberia and North America), which determines the great depth of their erosional dissection, is the result of neotectonic movements. The surface of the plains, in general, can be horizontal, inclined, convex, concave. The general character of its relief is varied: flat, hilly, wavy, stepped, etc.

The following plains are distinguished by absolute height:

- lowlands- their absolute height is from 0 to 200 m (Amazonian);

- hills- from 200 to 500 m above the ocean level (Central Russian);

- plateaus- over 500 m above the ocean level (Middle Siberian Plateau);

- depression- plains lying below the ocean level (Caspian).

The main geomorphological processes on the plains include fluvial, glacial, and eolian processes.

Surface flowing water is one of the most important factors in the transformation of the Earth's relief. The totality of geomorphological processes carried out by flowing waters is called fluvial. Watercourses perform destructive work - erosion, material transfer and accumulation and create worked out (erosive) and accumulative landforms. Both are closely related to each other, since what was carried away by water in one place is deposited somewhere else. Erosive work - difficult process and it is composed of a number of private processes:

From the entrainment of clastic rock material entering the channel from the weathered steep slopes of the valley;

From grinding or scraping (corrosion) of the bottom of the channel by solid material drawn along it (sand, pebbles, boulders);

From the dissolution of some rocks (limestones, dolomites, gypsum) with water, exposed in the channel.

A common feature of the erosive work of watercourses is its selective, selective nature. During the development of the channel, the water, as it were, reveals the most pliable areas for cutting, adapting to the outcrops of more easily eroded rocks. Where kinetic energy ("living force") flowing water falls sharply due to a decrease in slope or water flow, an excess of transported solid material is deposited in the channel of the watercourse or on a flat horizontal surface onto which the river exits the mountains: sedimentation or accumulation occurs. In addition to river valleys, under the influence of erosion, ravines and gullies are formed (erosion forms created by intermittent watercourses and often forming complex-branched systems).

As examples of plains, on which one of the main geomorphological processes are fluvial, one can cite such as the Russian Plain, the Mississippi Lowland.

Glacial relief-forming processes are due to the activity of ice. A prerequisite for the development of such processes is glaciation, i.e. long-term existence of masses of ice within a given area of ​​the earth's surface. During geological history On the Earth, conditions arose more than once under which the largest covers of continental ice were formed, extending over many millions of square kilometers.

The glacier performs denudation, transport and accumulation works. The destruction of rocks is called exaration. The plains are dominated by glacial accumulation. The material carried by the glacier accumulates where the flow of ice through melting and evaporation predominates. This material is accumulated at the edge of the glacier in the form of a ridge, repeating in terms of the outline of the edge. The ridge is usually curved in the form of a horseshoe and is called the terminal moraine. With intensive melting and retreat of the glacier, several terminal moraines are formed. As a result of the melting of the glacier, the bottom moraine is exposed from under the ice; There is a thick cover of detrital deposits, called the main moraine.

The glacial relief is characteristic of the North German and Polish plains, the Russian plain.

Eolian processes are associated with the effect of wind on the relief. The wind captures, separates from the surface and carries unbound soil particles. This process is called deflation. A somewhat smaller denudation role is played by the knocking out of weakly bonded particles and the destruction of rocks due to dynamic shocks of the air flow together with those moving in this flow. solid particles- eolian corrosion.

3.1. Genetic types of plains.

Primary plains, or marine accumulation plains- the most extensive in area. They are formed as a result of marine accumulation during temporary flooding of platform areas by transgressions of shallow epicontinental seas with their subsequent transformation into land during oscillatory positive motion. They represent the seabed exposed from under the water, covered with sedimentary marine deposits, usually already covered with a layer of eluvium or some other continental formations (glacial, fluvial, eolian), often defining the secondary micro- and mesorelief of these plains. Plains of the European part can serve as examples of marine accumulation plains. former USSR, West Siberian Plain, Caspian lowland.

Alluvial plains are formed as a result of the accumulative activity of rivers and are composed of layered river sediments from the surface. The thickness of the latter in some cases can reach a very significant thickness - several tens and even hundreds of meters (lower reaches of the Ganga river, the Po river valley, the Hungarian lowland), in others - it forms only a thin floor over eroded bedrock. The first takes place in river deltas and in areas of tectonic subsidence river basins, the second - in normal floodplains of mature river valleys. The alluvial plains include the Kura-Araks, Upper Rhine and other plains.

fluvioglacial plains. The transfer, sorting and redeposition of solid clastic material over large areas can also be carried out melt water glaciers flowing from under their ends or edges. These waters usually do not have the nature of regular permanent streams near their exit, often changing their water content and direction of flow from the place of exit from under the ice. They are overloaded with rewashed clastic material of moraines, sorting by size, transporting and depositing it, widely distributing it during their wandering in front of the glacier front. Examples include the Munich and other plains at the northern foot of the Alps, the Kuban, Kabardin, Chechen plains at the northern foot of the Greater Caucasus.

lake plains represent the flat bottoms of former lakes, dried up either as a result of the descent by the rivers flowing from them, or as a result of the disappearance of the dam, or due to the filling of their baths with sediment. Along their margins, such lacustrine plains are often outlined by ancient coastlines, expressed in the form of low abrasion ledges, coastal ridges, coastal dune ridges or lake terraces, indicating the former level of the lake. In most cases, plains of lacustrine origin are of insignificant size and are much inferior in size to the first three types. An example of one of the most extensive lacustrine plains is the plain of the Quaternary glacial Lake Agassiz in North America. The plains of Turaigyr-kobo, Jalanash and Kegen in Kazakhstan also belong to the lake plains.

Residual or marginal plains. These names mean spaces that originally had a large absolute altitude and a pronounced relief, which perhaps once even represented a mountainous country, which acquired a flat character only as a result of a long-term impact of exogenous factors of destruction and demolition - pppa.ru. These plains are, therefore, in the final stage of the descending development of a mountainous country, assuming a prolonged state of relative tectonic quiescence, which, apparently, rarely occurs. As an example of a marginal plain, already somewhat modified by subsequent processes, one can cite the North America sloping plain sloping gently to the east.

Volcanic upland plateaus. They arise when huge masses of predominantly basic lava pour onto the surface through cracks in the earth's crust. Spreading due to its great mobility over vast areas, the lava fills and buries all the irregularities of the primary relief and forms huge lava plateaus. Examples are the Columbian basalt plateau of North America, the trap plateau of the northwestern Deccan, and some parts of the Transcaucasian Highlands.

4. Conclusion

As a result of writing the work, I got acquainted with the processes that formed the main forms that make up the Earth's relief - mountains and plains. Familiarize yourself with the literature on this topic.

This work can be used in learning activities(not only school, but also university).

In general, the study of the origin of the plains and modern forms their surface is of great economic importance, since the plains are densely populated and developed by man. They have many settlements, a dense network of communications, large forests and agricultural land. It is with the plains that one has to deal with when developing new territories, designing the construction of settlements, communication lines, and industrial enterprises.

5. References

1. Leontiev, O.K. General geomorphology / O.K. Leontiev, G.I. Levers. - M .: Higher. school, 1988. - 319 p.

2. Lyubushkina, S.G. General geography: textbook. allowance for students. higher textbook establishments on special "Geography" / S.G. Lyubushkina, K.V. Pashkang; ed. A.V. Chernov. – M.: Enlightenment, 2004. – 288 p.

3. Milkov F.N. General geography: textbook. for stud. geographer. specialist. universities / F.N. Milkov. - M .: Higher. school, 1990. - 335 p.

4. Rychagov, G.I. General geomorphology: textbook. 3rd ed., revised. And extra. / G.I. Levers. - M .: Publishing House of Moscow. un-ta.: Nauka, 2006. - 416 p.

5. Engineering geology [Electronic resource] : scientific reference resource / Access mode: http://www.pppa.ru/geology/about02/. Date of visit: 03/07/2011

APPENDIX

Attachment 1.

Appendix 2. Collision of platforms and bowing of the earth's crust on I stage of the era of folding

Appendix 3. The emergence of mountains. II folding stage.

The most commonly used and almost generally accepted unit of the tectogenic series is the country. Many authors call it physical-geographical, and some even call it landscape. The first term is too broad, because all taxonomic units of both unilateral and landscape GCs are physiographic. However, in order to reduce discord in terminology, the use of the name "physico-geographical country" is acceptable, while the term "landscape country" seems completely unacceptable (see below).

Countries are also still large parts of continents (sometimes two neighboring continents). There are also island countries. The leading factor in the isolation of countries is the most general and significant differences in the neotectonic regime within the subcontinents. The indicator of this tectogenic unit is the predominance of plain or mountainous terrain the same genetic type. Consequently, a country typically corresponds to either a flat area of ​​a platform or a mountainous area of ​​a fold belt of a certain neotectonic regime and folding age. For example, the West Siberian country (Fig. 10) corresponds to the lowland of the same name, which is confined to a young (Epipaleozoic) platform, neotectonically almost stable (neotectonic uplifts and subsidences of very small amplitude - see FGAM, 1964).

But often countries, especially mountainous ones, combine two or more morphostructural regions for more low rank. So, the country of the Near Asian highlands consists of the Asia Minor, Armenian and Iranian highlands. it specific example implementation of the method of combining "small" GCs, because, according to at least, the first two highlands (the Iranian highlands, perhaps, is a special country), having a number of significant tectogenic similarities, individually do not meet the criterion of the complexity of the country. In other cases, non-compliance with this criterion forces us to use the method of joining a "small" GC when selecting countries. An example is the East European country, which consists not only of the vast plain of the same name on a Precambrian folded base, corresponding to the criterion of the complexity of the country, but also of a relatively small and monotonous plain, which is confined to the Paleozoic Scythian (South Russian) plate; this plain is a "small" GC.

Already from the foregoing it follows that the countries are divided into lowland and mountainous. However, so common division often not enough. Due to the fact that in the mountainous countries there are areas with a flat relief, and in the plains - with a mountainous one, and the role of the plain or mountainous relief, respectively, can be different, the lowland countries are divided by us into plains proper and mountainous plains, and mountainous countries into mountainous ones proper. and plain-mountainous. When using this classification, the word "properly" in the names of lowland and mountainous countries can be omitted (see Fig. 10).

In lowland countries, mountainous areas are either absent or small in size and occupy a small part of the country (for example, the East European Plain Country). In mountainous countries the same role flat territories(example - Central Asian mountainous country). In mountainous-plain countries, with a general predominance of flat relief, the role of mountainous regions is significant, and among them there are large ones. An example is the North European mountainous plain country. In addition to the predominant basement plains of the Baltic Shield, it includes the Scandinavian blocky highlands. In the lowland-mountainous countries, the ratio of the plain and mountainous relief is inverse compared to the mountainous-plain countries (for example, the lowland-mountainous country of North-Eastern Siberia).

When identifying countries, their compliance with the complexity criterion is especially important, because the combined taxonomic unit is not used at this stage of zoning. This is mainly due to the fact that the country serves as the largest unit of layout of physical and geographical material in the text characteristic of the Civil Code ( section VII, 2), and not only tectogenic units of a lower rank are described within the country, but also landscape HAs. Given this country function, it is essential that countries be comparable in terms of size and complexity of structure.

When identifying a country's compliance with the complexity criterion, it should be borne in mind that the above feature is not applicable for this unit: division into at least two GCs of directly lower rank. The fact is that the next unit - subcountry - is not mandatory, since some countries are not divided into subcountries. Therefore, when identifying the compliance of the allocated territorial units with the criterion of the complexity of the country, the only way remains: their comparison with the reference and extreme GCs. given rank. For countries, this basic method of determining compliance with the criterion of complexity (see Section II, 6) is applicable, because in the allocation of these GCs, especially on the territory of the USSR, Soviet geographers have already achieved significant unity.

When determining the compliance of tectogenic HAs with the criterion under consideration, it must be taken into account that the complexity of their structure is determined not only by their tectonic-geomorphological, but also by zonal and sectoral complexity. This is explained as follows. Those features of zonal and sectoral HAs that are determined by the peculiarities of the tectonics and topography of the territory, i.e., are genetically subordinate to these features, can be legitimately considered as manifestations of tectogenic differentiation. One of them is, for example, that in mountainous countries zones are expressed not directly, but through types of altitudinal zonality. The latter are nothing but mountain tectogenic variants of the corresponding zones of the plains. But even in the lowland countries, zones and subzones are represented by special tectogenic variants. Thus, the East European Plain is characterized by a relatively well-drained taiga, and the West Siberian country is much more swampy. The more zones, subzones, sectors, subsectors a country crosses, the more tectogenic variants of these climatogenic HAs are within its boundaries and the more complex its structure.

The complexity of the structure of tectogenic HAs is also somewhat dependent on their area. Larger countries usually overlap a large number zonal and sectoral GCs. But even with the same zonal and sectoral complexity, those large tectogenic HAs that are relatively simple in terms of tectonics and geomorphology are comparable in complexity and diversity. natural conditions with GCs occupying a smaller area, but characterized by a more complex relief. Even a comparatively uniform relief in separate parts of a large territory varies, which leads to a certain heterogeneity of other components as well, and, consequently, increases the "total" diversity of its nature.

The tectonic-geomorphological, zonal, sectoral and "areal" components of the complexity of the structure of physical-geographical countries can, as it were, compensate each other. Thus, mountainous countries, generally speaking, should be smaller in area than flat ones. It is legitimate to refer to countries as mountainous or plain-mountainous territories that do not have great height and a variety of topography, as well as a vast area, but complex in zonal or, even more so, zonal and sectoral relations. An example is the Novaya Zemlya-Ural plain-mountainous country, located in seven zones and two sectors (cf. Fig. 10, 7, 2). Further, a tectogenic country cannot be zonal homogeneous, because otherwise it would turn into a landscape unit - a region. However, high mountainous and lowland-mountainous countries with a complex relief can be simple in terms of sectoral and zonal terms, in particular, they can be located in only two or three zones, and even predominantly in one of them. An example is the Central Asian mountainous country, which does not go beyond the limits of one sector and lies for the most part in the zone of subtropical semi-deserts and deserts.

Non-compliance with the criterion of complexity does not allow us to consider a large tectogenic HA as a country. For example, unlike a number of authors (FGAM, 1964), we do not include the Yakutsk Basin among the countries. It is located within one subsector, one zone, and, moreover, mainly within the same - middle taiga - subzone. In addition, the basin does not have a complex relief, and is even inferior in area to many mountainous countries (apparently, similar considerations apply to the selection of subcontinents. But when taking into account the zonal complexity of these units, not zones, but geographical zones should be taken into account).

When identifying tectogenic countries and constructing their boundaries, the leading importance is given not to neotectonic, but to paleotectonic similarities and differences, if, of course, they are expressed in the modern topography, petrographic composition of rocks, and at least in some other geocomponents. The priority of paleotectonics in this case is explained by several reasons. First, the structural and petrographic features of many territories are mainly or largely associated with paleotectonics. And these features play an important relief and landscape-forming role. Secondly, paleotectonic units usually coincide with paleogeographic units that differ in the common development in the geological past. Therefore, paleotectonic units are convenient for characterizing the history of the formation of the modern relief of countries, the roots of which often go far into the depths of the geological past. Thirdly, the country is a tectogenic unit, the most convenient for taking into account the paleotectonic similarities and differences of territories in the course of physical and geographical zoning. Subcontinents are unsuitable for this purpose, because they are heterogeneous in paleotectonic terms. When identifying tectogenic units with a rank below the country, the possibilities for taking into account paleotectonic features during zoning are much less, since direct links between paleo- and neotectonics are much less common in these units than in countries. The latter, however, correspond to the main types of morphostructures, in the identification of which IP Gerasimov and Yu. A. Meshcheryakov (FGAM, 1964) assign an important role to paleotectonics.

However, it must be emphasized again that in this case we are talking not about any paleotectonic similarities and differences, but only about those that are expressed in the relief, i.e., corrected by neotectonics. If the same type of paleotectonic structures are significantly different in neotectonic regime, then, of course, they cannot be combined into one country. This applies, for example, to the Paleozoic structures of the Tien Shan mountain system and the Kazakh uplands. The former experienced intense and highly differentiated neotectonic movements; secondly, the neotectonic regime was closer to that characteristic of the plains.

Therefore, the indication of the priority of paleotectonics in the identification of countries is somewhat arbitrary and, in essence, does not contradict the neotectonic leading factor in the isolation of these tectogenic HAs. Priority should be understood only in the sense that preference is given to paleotectonic features if territories with more or less similar morphometric characteristics of the relief are zoned. Thus, the Trans-Ural peneplain has a transitional character from the eastern foothills of the Urals to the layered plains of the West Siberian Lowland. Although the topography of the peneplain is generally closer to the plains than to the mountains, based on the priority of paleotectonics, the peneplain should be included in the Novaya Zemlya-Ural plain-mountainous country. Within its limits, the rocks of the Ural-Tian-Shan Paleozoic geosyncline prevail in the surface occurrence, and the structural and petrographic features of the latter are manifested in the relief and in some other aspects of the nature of the peneplain (for more details, see: Prokaev, 1973, where other examples are given, as well as exceptions to the rule). The borders of the Novaya Zemlya-Ural and West Siberian countries are drawn where the hercynides of the Urals are overlain by Cenozoic loose deposits in most of the area and are no longer expressed in the relief and other geocomponents.

The considered methodological provisions are nothing more than the implementation of the genetic approach in the selection of countries. It is important that in this case it is not general position, but specified in the form of a specific methodology. It is based both on the objective role of paleotectonic and neotectonic differences in the separation of tectogenic HAs, and, in particular, on an expedient system for taking these differences into account during regionalization, i.e., ultimately, on the principle of comparability of its results.

What has been said about the country can be summarized as the following definition of this most important unit of the tectogenic series. A country is a large tectogenic geocomplex, usually confined to a flat area of ​​a platform or a mountainous area of ​​a folded belt of a certain neotectonic regime and age of folding. With the general predominance of mountainous or flat relief of one genetic type, there may be large areas inside the country that differ significantly from the typical neotectonic movements and relief (areas of mountainous relief in lowland countries and plains in mountainous countries; the role of both flat and mountainous relief). The unity of the country in terms of tectonics and geomorphology determines the specific nature of zonality within its boundaries, the isolation of specific variants of zones and subzones that cross the country.

Many Soviet geographers consider the country not as a one-sided tectogenic, but as a landscape GC (for example, "Physical-geographical zoning of the USSR", 1968). Moreover, they argue that the country is characterized not only by tectonic and geomorphological commonality, but also by sectoral unity, as well as a certain set of horizontal zones and types of structure of altitudinal zonality (here and below, when discussing other points of view, our terminology is usually used, and not the terminology of the corresponding authors. This essentially shortens the exposition, because the meaning of our terms is already known to the reader). In other words, according to these scientists, the country is a truly complex unity, since when it is distinguished, not only morphostructural, but also sectoral, zonal and altitudinal features are taken into account.

However, it is impossible to agree with the above considerations. Countries are often sectorally heterogeneous, occupying parts of two or sometimes three sectors. For example, the border of the temperate continental and continental sectors of Eurasia only on the territory of the USSR crosses the West Siberian, Novaya Zemlya-Urals, East European and Crimean-Caucasian countries (cf. Figs. 2 and 10).

The presence within each country of a certain set of zones is by no means proof that the country is a landscape unity. After all, a set of zones is characteristic of any large territory, even if it is enclosed in political, administrative or any other non-natural boundaries. The set of zones is determined not by the tectonic and geomorphological basis of the country, but by its position in planetary system zones and sectors, which is largely independent of morphostructures. Therefore, the boundaries of physical-geographical countries are completely inconsistent with the boundaries of the zones, they are intersected by them.

Although countries differ from each other in the nature of the same zones, this is a manifestation of not zonal, but tectogenic differentiation. Therefore, the presence of specific tectogenic variants of zones within each of the countries cannot be considered as a sign of their zonal homogeneity. According to the actual zonal features of nature, due to planetary differences in the amount and ratio of heat and moisture, the countries are heterogeneous. Namely, the most significant, background features of their soils, vegetation and wildlife are associated with the zonal and sectoral features of the territories. Consequently, countries that are distinguished by the homogeneity of the main features of the tectonic-geomorphological component are heterogeneous in terms of the most important features of the climate and biocomponents. Therefore, in relation to a given physical-geographical unit, one cannot speak of a comparable homogeneity of all geocomponents (an example has already been considered in Section II, 2).

Let us briefly dwell on an additional unit of the tectogenic series - a subcountry, or a group of krais (the first name is preferable: it is constructed in the same way as the names of a number of other zoning units (see the commonly used "subregion", "subdistrict", etc.)). Subcountry - the largest, orographically clear separate part countries (mountain system, highlands, etc.). For example, in the Central Asian mountainous country, the sub-countries are Tien Shan, Pamir-Alay, Hindu Kush; in Asia Minor - Asia Minor, Armenian and, possibly (see p. 68) Iranian highlands. Each of these regions is comparable in complexity of the geological structure and relief with some countries, for example, with the Novaya Zemlya-Urals. Therefore, tectogenic regions, landscape regions and provinces, if they are singled out directly within such countries, turn out to be incomparable in tectonic and geomorphological complexity with the similar units of countries that are relatively simple orographically. This makes it necessary to single out named units within sub-countries, which in this case, as it were, replace countries. Subcountries are also necessary for the textual physical-geographical characteristics of countries consisting of several large orographic units.

In concluding the section on the country, let us touch on the complex and little-developed question of the position of the islands in the system of countries (or sub-countries) of the land. It seems that the mainland islands should be considered as a special country if their totality meets both criteria for the rank of this unit (for example, the Philippine-Malay island mountainous country). In the absence of such a correspondence, the mainland islands should be included in those countries that are similar to them in tectonics and geomorphology. For example, the Franz Josef Land archipelago is part of the East European flat country, about. Newfoundland is part of the Appalachian lowlands.

When determining the rank of groups of oceanic islands, it is necessary to widely use the methods of combining and joining "small" GCs, as well as a combined taxonomic unit. So, the numerous small islands of Polynesia, occupying the vast water area of ​​the Pacific Ocean, can be considered as a combined unit - a subcontinent-country (Polynesia itself, apparently, cannot be considered a subcontinent due to the small total area of ​​the islands and their significant genetic uniformity, see FGAM, 1964) . The islands of Eastern Micronesia, located, like the islands of Polynesia, within an ancient oceanic platform (thalassocraton), are probably a subcountry of the Polynesian subcontinent-country. Western Micronesia, which is part of the Pacific geosynclinal belt, is a subcountry of either the Philippine-Malayan or East Asian mountainous island countries, or is divided between them (this issue requires special study).

The issue of dividing the World Ocean into large tectogenic GCs located in several geographical zones and corresponding to the physical and geographical countries of the land has not yet been resolved ( physical geography World Ocean, 1980).