General features of the relief of foreign Europe. General features of the relief of Russia

On the hypsometric map of Russia and on images from space, the orographic pattern of the entire territory of our country is clearly visible. It is characterized by a complex mix of low and raised plains, plateaus, highlands and mountains.

On huge plains, vast areas are occupied by lowlands with heights of less than 200 m, among which in some places there are scattered hills and individual island ridges. The SS plains are raised higher; these are rather plateaus heavily indented by valleys, especially along the edges. They form, as it were, a step in the transition from the lowlands of the west of the country to the highlands of its east. Most plains have a stable basement for a long time, a calm geological regime. But in the distant past, the plains either submerged or rose, and more than once served as the bottom of the sea, and their very plain is often due to strata deposited in the ancient seas.

The mountainous regions of the country, in contrast to the plains, are not so calm: the earth's crust is here and now mobile, subject to compression, distortion, fragmentation, especially intensive uplifts and subsidence; it is the arena of ongoing modern mountain building.

The map shows that the mountainous outskirts of our country are divided into three heterogeneous stripes - southern, eastern and diagonal. South - a link of the Alpine-Himalayan belt of geologically young mountain structures (Caucasus). The eastern strip is a link in an even younger East Asian belt of mountains, and together with it - a part of the grandiose ring of mountain systems, which embraces the Pacific Ocean on almost all sides (Sikhote-Alin, Kuril-Kamchatka ridge, Sakhalin). The third strip of mountains obliquely crosses the eastern half of the country from the uplands of Chukotka and Kolyma to the south of Siberia.

The southern and eastern stripes are not only zones of the latest vertical uplifts, but also of the most recent folding. In contrast to them, the structures of the third band are built by folds of various, including the most ancient, age. However, the latest uplift here also took place a long time ago, as well as in zones of young folding.

But not all the links of the folded margins were raised at the last stage of geological history. Some, on the contrary, sank and in places turned out to be flooded by the seas - the Pacific, Caspian, Black. Therefore, the bands of uplifted folds do not form continuous barriers, but alternate with depressions, depressions, and here and there, in coastal areas, form islands.

Mountain fringes could exist in the north of the country, but the land here for a large extent sank under the waters of the Arctic seas, and the mountain systems turned into isolated archipelagos. This is how Franz Josef Land and Severnaya Zemlya emerged. The northern continuation of the Ural mountain rampart separated itself in the form of two islands of Novaya Zemlya.

This is, in the most general outline, the picture of the horizontal dissection of the land surface of our country. But dismemberment in plan is also characteristic of the coasts, where peninsulas and islands, bays and straits differ.

The largest bays represent whole seas: Baltic, White, Black with Azov, Okhotsk, each of them has its own dead-end bends.

The Far Eastern seas - the Bering and the Japanese -, in contrast to the "seas-bays", are "seas-straits". Each of the marginal seas of the Arctic Ocean is also a kind of bay-strait: they are delimited by archipelagos of islands, interrupted by straits.

The bottom of the seas has its own relief, in which one can distinguish between plains and mountain systems (for example, a strip of mountains with mountain ranges of Mendeleev, Lomonosov and Otto Schmidt in the Central Arctic), and the deepest depressions, including the Kuril-Kamchatka, the third in the world in depth , reaches 10,540 m below ocean level. The relatively shallow bottom near the Arctic seas rises above the depths of the central parts of the Arctic Ocean like a balcony, forming a continental shelf or shelf.

Plains are concentrated mainly in the western half of Russia, and plateaus, highlands and mountains predominate in the east - from the Yenisei valley to the shores of the Pacific seas. Plains make up about 60% of the territory. The two largest of them - BE and ZS - are among the greatest plains in the world. Medium-altitude mountain systems stretch like a solid barrier parallel to the coasts of the Pacific Ocean seas. In the south, along the border, there is a belt of high mountains, from which the entire territory drops to the Arctic Ocean. The largest rivers of Siberia - the Ob, Yenisei, Lena - flow to the north along this slope. And to the south from the Arctic, powerful currents of cold air pass through the plains.

The southern belt of mountains is included in the belt of high uplifts of Eurasia and consists of separate mountain systems of different ages: the Caucasus, Altai, Sayan, Baikal and Transbaikalia. The Caucasus and Altai are among the high mountains of Eurasia.

Climate is a long-term weather regime that has developed as a result of the interaction of the atmosphere with all natural and geographical factors and is subject to the influence of space and human economic activity.

The climate of Russia is formed under the influence of a number of climate-forming factors and processes. The main climate-forming processes are radiation and circulation, which are determined by the conditions of the territory.

Radiation- incoming solar radiation is an energy base, it determines the main flow of heat to the surface. The farther from the equator, the smaller the angle of incidence of the sun's rays, the smaller the amount supplied. The expenditure part consists of reflected radiation (from the albedo) and effective radiation (it increases with decreasing cloud cover, the total - from north to south).

In general, the radiation balance in the country is positive. The only exceptions are some islands in the Arctic. In winter it is negative everywhere, in summer it is positive.

Circulating... Due to the different physical properties of land and the ocean, there is unequal heating and cooling of the air in contact with them. As a result, there are movements of air masses of various origins - atmospheric circulation. It proceeds under the influence of low and high pressure centers, their position and severity change seasonally. However, in most of our country, westerly winds prevail, bringing Atlantic air masses, with which the main precipitation is associated.

The influence is especially great in winter, due to the western transport of warm and humid air masses from the Atlantic.

The large size of the territory of our country, the presence of vast valleys and large mountain systems have led to a clear zonal provincial distribution of soils, vegetation and animals. The main conditions for the formation of biocomponents are the ratio of temperature and moisture. the relief of the territory and the degree of continentality of the climate have a significant impact on their distribution.

The unity of the biocomplex is due to the zonal structure of atmospheric processes, the interaction of all components of nature and the long history of the development of the territory in the Phanerozoic.

The distribution of soils, vegetation and animals on the territory of Russia determines the law of zoning on the plains and altitudinal zoning in the mountains. Therefore, when moving along the meridians or along the slopes of mountains, due to changes in hydro-climatic conditions, there is a gradual change of some types of soil and vegetation, as well as animal complexes, by others.

But at the same time, the increasing continentality of the climate to the east (up to certain limits) and the different geological history of large geostructures (platforms and folded belts) led to the differentiation of soils, vegetation and fauna, i.e. to the manifestation of provinciality (sector).

The peculiarities of the territory orography are predetermined by the complex geological history and various geological structures. Large lowlands, plains and plateaus correspond to platforms, and mountain structures correspond to folded belts.

The territory of Russia is located on several lithospheric plates: the northern part of the Eurasian, the western part of the North American, the northern part of the Amur. And only the Okhotsk plate is almost entirely located on the territory of the country.

The earth's crust within Russia, as elsewhere on Earth, is heterogeneous and uneven in age. It is heterogeneous both in plan and in vertical direction.

More rigid, stable parts of the earth's crust - platforms - differ from the more mobile ones - folded belts, which are more susceptible to both compression and vertical swing. As a rule, the platforms are characterized by a two-tier structure, where a crushed crushed base and a cover of horizontal layers covering it are distinguished.

The most ancient platforms are the Precambrian. Their foundation is not only complicated by the oldest rocks, which are more than 570-600 million years old, but was also crumpled into folds before the strata of subsequent eras appeared. This is the structure of our two vast platforms, which are among the largest in the world.

In those parts where the oldest structures of the Earth were not flooded with seas, or where marine sediments were eroded in subsequent eras, an ancient foundation - the so-called shields - comes to the surface. There are also underground outcrops of the basement, which are close to the surface (Voronezh crystalline massif). Don only in one place reached its vault.

Stable platforms increased in size over time - sections of neighboring folded zones were soldered to them, which acquired rigidity in the process of crushing. At the end of the Precambrian era, i.e. 500-600 million years ago, the Baikal folding sharply increased the Precambrian core of the future Siberian platform: huge folded massifs of the Baikal region and parts of Transbaikalia joined the Aldan shield.

During the Paleozoic era, powerful folding shook the earth's crust twice. The first, called the Caledonian folding, took place in several stages in the Early Paleozoic, 300-400 million years before the present day. The folds in the center of the Sayan Mountains remained his monuments. The second, called the Hercynian folding, took place in the Late Paleozoic (200-250 million years ago) and turned a huge trough of the earth's crust between the Russian and Siberian platforms into the Ural-Tien Shan fold zone. As a result of this folding, the Russian and Siberian platforms merged into an integral continent - the basis of the future Eurasia.

In a wide belt adjacent to the Pacific Ocean, the main stage of crustal collapse was the Mesozoic era - 60-190. its structures, called the Pacific ones, extended the Siberian platform from the east, forming powerful folded areas in Primorye, Amur, Transbaikalia and in the northeast of Siberia.

After the Mesozoic movements, only two vast strips, where a restless regime remained, did not lose their pliability to crumples. One stretched across the Alps and the Caucasus to the Himalayas. The second strip, bordering the east of Asia and including the western outskirts of the Pacific Ocean, is the East Asian fold region. Both areas continued to exist not only in the Mesozoic, but also later. It was in the Cenozoic, i.e. in the last 60 million years, they have been the scene of powerful collapses. The last of the folds, the Alpine, developed here, during which the bowels of the Caucasus, Sakhalin, Kamchatka and the Koryatsky Upland were crushed. These active areas continue to exist today, showing their activity by numerous earthquakes, and volcanism in the East Asian mountain-island arcs.

In the second half of the Alpine era of folding - in the Neogene, 10-20 ml. years ago, a completely new stage in the history of the earth's crust began, which was of particular importance for the modern relief. It is associated with the latest, or neotectonic movements, mainly vertical uplifts and subsidences, which encompassed not only the alpine mobile zones, but also structures of various ages that are significantly distant from them.

The youngest folded zones, the Caucasus, Sakhalin and the Kuril-Kamchatka arc, have been very intensely affected. All these mountainous countries exist now not so much as a result of recent folding, but as a result of the recentness and intensity of these recent vertical uplifts. In the general diagonal belt of mountains, structures of different ages were involved in the uplift, such as the Precambrian (south of the Aldan Shield, Baikalids of the Stanovoy Range and Highlands), Paleozoic (Hercynides of Altai, Urals), Mesozoic (northeast Asia). Recent movements were expressed not only in uplifts, but also in lowering. Depressions of the earth's crust have created the modern appearance of the depressions of the seas and large lakes, many lowlands and depressions (Baikal). The piedmont depressions adjacent to the young mountains underwent especially strong diving.

The stability of the platforms in relation to crushing does not mean immobility in general. Both platforms and folded areas are subject to a different type of movement - alternating vertical vibrations (concepts and descents).

The relationship between the relief and the structure of the earth's crust is approximately as follows: the higher the surface, the greater the thickness of the crust. The largest is where the mountain formations are (40-45 km), the smallest is the basin of the Sea of ​​Okhotsk. Isostatic equilibrium. At the contact of the Eurasian and North American plates, the plates move apart (Momsky rift) and a zone of diffuse seismicity is formed. The latter is also typical for the margin of the Okhotsk plate. At the contact between the Eurasian and Amur regions, there is also a separation - the Baikal rift. Okhotomorskaya at the contact with the Amurskaya (Sakhalin and the Sea of ​​Japan), the convergence of plates is 0.3-0.8 cm per year. The Eurasian is bordered by the Pacific, North American, African (Arabian) and Indian (Hindustan-Pamir). The compression belts of the lithosphere between them are Alpine-Asian in the south and Tsirkum-Pacific in the east. The edges of the Eurasian Plate are active in the east and south and passive in the north. In the east - the submersion of the oceanic under the mainland: the junction zone consists of marginal seas, island arcs and a deep-sea trench. In the south, there are mountain ranges. Passive margins in the north - a huge shelf and a distinct continental slope.

Eurasia is characterized by linear and ring structures, established according to satellite imagery data, geological-geophysical and geological studies. seismic cores of the continental crust. Nuclear, 14.

The heat flow of the Earth on the territory of Russia has different meanings: the smallest values ​​are on ancient platforms and the Urals. Elevated - on all young platforms (slabs). The maximum values ​​are folded belts, the Baikal rift, marginal TO seas.

With depth, the temperature in the Earth gradually increases. Under the oceanic plates, the temperature of the mantle reaches the melting point of the mantle rocks. Therefore, the surface of the beginning of melting of mantle material is taken as the base of the lithosphere under the oceans. Below the oceanic lithosphere, the mantle material is partially molten and plastic with reduced viscosity. The plastic layer of the mantle stands out as an independent shell - the asthenosphere. The latter is clearly expressed only under the oceanic plates, practically absent under the thick continental plates (basaltic magmatism). In the boundaries of the continental plates, it can manifest itself only when the hot mantle matter, due to the split of the plate, can rise to the level of the beginning of melting of this matter (80-100 km).

The asthenosphere has no ultimate strength and its substance can deform (flow) under the action of even very small excess pressures, although very slowly due to the high viscosity of the asthenospheric substance (about 10 18 - 10 20). For comparison, the viscosity of water 10 -2, liquid basaltic lava 10 4 - 10 6, ice - about 10 13 and rock salt - about 10 18.

The movements of lithospheric plates over the asthenosphere surface occur under the influence of convective currents in the mantle. Individual lithospheric plates can diverge, approach, or slide relative to each other. In the first case, tension zones with rift cracks appear between the plates along the boundaries of the plates, in the second, compression zones accompanied by the thrust of one of the plates onto the other, in the third, shear zones, transform faults, along which the neighboring plates are displaced.

As the main categories of tectonic regions, we will single out: 1. relatively stable regions - ancient platforms, mainly with a pre-Upper Proterozoic metamorphic basement, 2. mobile mobile belts of the Neogean, consisting of folded regions of different ages (in the place of dead geosynclinal regions) and modern geosynclinal regions, 3.areas, transitional - metaplatforms.

Ancient platforms, or cratons, represent vast areas of the ancient continental crust, measured in millions of square kilometers, largely formed in the Archean and almost entirely by the end of the Early Proterozoic. Neogei is a relatively calm tectonic regime: "sluggishness" of vertical movements, their weak differentiation in area, relatively low rates of uplifts and subsidence (less than 1 cm / thousand years). At the early mega-stage of development, most of their area was uplifted, and the subsidence mainly involved narrow linearly elongated graben-like depressions - aulacogenes. At a later, plate mega-stage (phanerozoic), a significant area of ​​platforms was drawn into the subsidence, on which a cover of almost undisturbed sediments was formed - a plate. Simultaneously with the sinking of the basement, the regions of the platforms were isolated within the limits of the plates, which for most of their history had a tendency to uplift and represent vast protrusions of the ancient basement - shields.

The cover of ancient platforms usually does not bear traces of metamorphic changes, which, like the absence or limited development of manifestations of magmatism, is explained by a significant decrease in the thermal regime during the formation of ancient platforms and, as a rule, by a low heat flow in most of their territory (except for aulacogens). However, in some zones of ancient platforms, manifestations of magmatism took place, and in some rare phases, due to anomalous heating of the upper mantle beneath them, ancient platforms could become the arena of powerful trap magmatism in effusive and intrusive forms.

Movable belts... They were founded mainly in the ancient Proterozoic. In its development, 2 mega-stages pass: geosynclinal (the greatest tectonic mobility, expressed in differentiated horizontal and vertical movements and a high, albeit inconsistent thermal regime in the crust and upper mantle) and postgeosynclinal (in place of dead geosynclinal belts, activity is reduced, but much more, than on ancient platforms).

The total duration of the goesynclinal process is 1-1.5 billion years, but in some areas it ends earlier. “Cycles”, the geosynclinal stage proper and the shorter orogenic stage (orogenesis) are distinguished.

Actually geosynclinal: stretching of the crust, the emergence of elongated graben-like depressions. Wide deflections break up into narrow ones. At the end there is actually a hesinkle. stages stop lowering. At the beginning of the orogenic stage, they undergo severe compressive deformations (from the inner zones to the periphery). They turn into folded structures. During the orogenic stage, they experience a gradually increasing uplift, not completely compensated by denudation, and at the late orogenic stage they turn into mountain structures. Thus, there is a complete reversal of the tectonic plan (geosynclinal troughs into mountain rises). At the same time, in the zones of growing folded structures, edge deflections appear to compensate for their uplift, in the rear - internal deflections or depressions filled with debris.

The "cycles" into which the process of development of geosynclinal belts breaks down end with a relative hardening of the crust, acquiring the features of a typical (mature) continental type crust over a significant (or entire) area. At the beginning of the next "cycle", this crust is partially destroyed and the geosynclinal regime is regenerated, while other areas are excluded from the further geosynclinal process.

In most of the North Atlantic mobile belt, the geosynclinal process ended in the middle of the Paleozoic, the Ural-Mongolian - at the end of the Paleozoic - early Mesozoic, for most of the Mediterranean belt, it is close to completion, and significant parts of the Pacific belt are still at different stages of the geosynclinal process.

Metaplatform areas... Something average in the nature of tectonic structures, the degree of mobility of the crust and the peculiarities of tectonic movements. At the borders. Structurally, it is a combination of two main types of tectonic elements - mobile aulacogeosynclinal zones and relatively "rigid" metaplatform massifs separated by these zones from ancient platforms. The aulacogeosynclinal zones represent linearly elongated zones of an intermediate character between the aulacogens of ancient platforms and the geosynclinal troughs of mobile belts. In the Late Proterozoic, simultaneously with the mobile belts framing the platforms, usually branching off from the latter. Tomb-base troughs - compression - metamorphism, intrusive bodies - folded zones (Donetsk, Timanskaya).

The role of climate in human life can hardly be overestimated. It determines the ratio of heat and moisture, and, consequently, the conditions for the occurrence of modern relief-forming processes, the formation of inland waters, the development of vegetation, and the placement of plants. The peculiarities of the climate have to be taken into account in the economic life of a person.

Influence of geographic location.

Air masses and their repeatability. Three types of air masses are characteristic of Russia: arctic air, temperate air, and tropical air.

Most of the country is dominated by air masses throughout the year. moderate latitudes, represented by two sharply different subtypes: continental and marine. Continental the air is formed directly over the mainland, it is dry throughout the year, low temperatures in winter and rather high in summer. Nautical air comes from the North Atlantic, and in the eastern regions - from the northern part of To. Compared to continental air, it is more humid, cooler in summer and warmer in winter. Moving through the territory of Russia, the sea air is quickly transformed, acquiring the features of the continental.

Arctic the air is formed over the ice of the Arctic, so it is cold, has a low absolute humidity and high transparency. Influence on the northern part of the country, especially SS and NE. In transitional seasons, it causes frosts. In summer, advancing and drying up more and more, it brings droughts and dry winds (south of the BE and WS). The air that forms over the Arctic can be called continental. Only over the Barents Sea is the Arctic marine being formed.

Tropical air over the southern territories, is formed over Central Asia, Kazakhstan, the Caspian lowland, the eastern regions of the Ciscaucasia and Transcaucasia as a result of the transformation of the air of temperate latitudes. Differs in high temperatures, low humidity and low transparency. To the south of the Far East, the tropical sea air sometimes penetrates from the central regions of To, and into the Caucasus from the Mediterranean. Differs in high humidity and high temperatures.

Atmospheric fronts.

Physical and geographical conditions of the territory... The underlying surface, over which they form and acquire new properties, has a great influence. So, in winter, humid air masses bring the latent heat of vaporization to a cold surface and warming sets in. In summer, humid air masses also bring precipitation, but evaporation and a slight cooling begins on the warm underlying surface.

The influence of the relief on the climate is great: with altitude, the temperature drops for every 100 meters by 0.6 ° C (due to a decrease in the radiation balance), atmospheric pressure decreases. Affected by exposure. Mountains play an important barrier role.

Special role - sea ​​currents... Warm North Atlantic, cold around the Kuriles, Kamchatka, the Sea of ​​Okhotsk.

Climatic features of the winter period. In cold weather on the territory of Russia, from October to April, an area of ​​increased pressure (Asian maximum) is established, an area of ​​reduced pressure near the eastern coasts (Aleutian minimum) develops and the Icelandic minimum increases, reaching the Kara Sea. Differences in pressure between these main baric centers of the winter period reach the greatest values ​​and this contributes to an exacerbation of circulation processes.

In connection with the western transport, the development of cyclones and anticyclones, the circulation processes are very pronounced and they largely determine the distribution of heat and moisture. The influence of the Atlantic, the Asian maximum, the Aleutian minimum and solar radiation is clearly traced.

From the Atlantic Ocean in winter, air masses bring a large amount of heat to the mainland. Therefore, in BE and the northern half of the ZC, the temperature decreases not so much from south to north as from west to east and northeast, which is confirmed by the course of the January isotherms.

The impact of the Asian maximum is reflected in the extremely low temperature of Central Siberia, the Northeast and the position of the isotherms. In the basins, the temperature reaches -70 (the cold pole of the northern hemisphere - Oymyakon and Verkhoyansk).

In the Far East, the Aleutian minimum and the Okhotsk branch of the Arctic front predetermines cyclonic activity, which is reflected in warmer and snowy winters than on the continent; therefore, the January isotherms run parallel to the coast.

The greatest amount of winter precipitation falls in the west, where air from the Atlantic enters in cyclones. From west to east and north-east, the amount of precipitation gradually decreases.

Climatic features of the summer period. The ratio of radiation and circulation conditions changes dramatically. The temperature regime is determined by radiation conditions - the entire land is heated much more than the surrounding water areas. Therefore, from April to October, the isotherms extend almost sublatitudinally. In July, throughout Russia, the average monthly temperatures are positive.

In summer, the Azores maximum moves to the north and its eastern branch penetrates the EE plain. From it, the pressure decreases to the north, south and east. The Arctic maximum remains above the SL. Therefore, cold air moves to the inner, warmer territories of Russia, where it heats up and moves away from the saturation point. This dry air contributes to the origin of droughts, sometimes with dry winds in the southeast of the EE Plain, in the south of the WS Plain and in the north of Kazakhstan. The development of dry, clear and warm weather is also associated with the spur of the Azores maximum. Above the TO, the North Pacific maximum moves to the north (the Aleutian minimum disappears), and the sea air rushes to land. The summer Far Eastern monsoon appears.

In summer, there is also a western transfer - from the Atlantic - the largest amount of precipitation.

All air masses entering the country in summer are transformed into continental air of temperate latitudes. On atmospheric fronts (arctic and polar), cyclonic activity develops. It is most pronounced on the polar front over the EE plain (continental and maritime temperate).

The Arctic front is expressed within the Barents and Kara Seas and on the coast of the eastern seas of the North Caucasus Region. Along the line of the Arctic front, cyclonic activity intensifies and causes prolonged drizzling rains in the subarctic and arctic belts. In summer, the maximum precipitation falls, which is associated with increased cyclonic activity, moisture content of air masses and convection.

Radiation and circulation conditions change in spring and autumn. In the spring, the negative radiation balance turns into a positive one, and vice versa in the fall. In addition, the position of the high and low pressure regions, the type of air masses, and, consequently, the position of the atmospheric fronts change.

On the hypsometric map of Russia and on images from space, the orographic pattern of the entire territory of our country is clearly visible. It is characterized by a complex mix of low and raised plains, plateaus, highlands and mountains.

On huge plains, vast areas are occupied by lowlands with heights of less than 200 m, among which in some places there are scattered hills and individual island ridges. The SS plains are raised higher; these are rather plateaus heavily indented by valleys, especially along the edges. They form, as it were, a step in the transition from the lowlands of the west of the country to the highlands of its east. Most plains have a stable basement for a long time, a calm geological regime. But in the distant past, the plains either submerged or rose, and more than once served as the bottom of the sea, and their very plain is often due to strata deposited in the ancient seas.

The mountainous regions of the country, in contrast to the plains, are not so calm: the earth's crust is here and now mobile, subject to compression, distortion, fragmentation, especially intensive uplifts and subsidence; it is the arena of ongoing modern mountain building.

The map shows that the mountainous outskirts of our country are divided into three heterogeneous stripes - southern, eastern and diagonal. South - a link of the Alpine-Himalayan belt of geologically young mountain structures (Caucasus). The eastern strip is a link in an even younger East Asian belt of mountains, and together with it - a part of the grandiose ring of mountain systems, which embraces the Pacific Ocean on almost all sides (Sikhote-Alin, Kuril-Kamchatka ridge, Sakhalin). The third strip of mountains obliquely crosses the eastern half of the country from the uplands of Chukotka and Kolyma to the south of Siberia.

The southern and eastern stripes are not only zones of the latest vertical uplifts, but also of the most recent folding. In contrast to them, the structures of the third band are built by folds of various, including the most ancient, age. However, the latest uplift here also took place a long time ago, as well as in zones of young folding.

But not all the links of the folded margins were raised at the last stage of geological history. Some, on the contrary, sank and in places turned out to be flooded by the seas - the Pacific, Caspian, Black. Therefore, the bands of uplifted folds do not form continuous barriers, but alternate with depressions, depressions, and here and there, in coastal areas, form islands.

Mountain fringes could exist in the north of the country, but the land here for a large extent sank under the waters of the Arctic seas, and the mountain systems turned into isolated archipelagos. This is how Franz Josef Land and Severnaya Zemlya emerged. The northern continuation of the Ural mountain rampart separated itself in the form of two islands of Novaya Zemlya.

This is, in the most general outline, the picture of the horizontal dissection of the land surface of our country. But dismemberment in plan is also characteristic of the coasts, where peninsulas and islands, bays and straits differ.

The largest bays represent whole seas: Baltic, White, Black with Azov, Okhotsk, each of them has its own dead-end bends.

The Far Eastern seas - the Bering and the Japanese -, in contrast to the "seas-bays", are "seas-straits". Each of the marginal seas of the Arctic Ocean is also a kind of bay-strait: they are delimited by archipelagos of islands, interrupted by straits.

The bottom of the seas has its own relief, in which one can distinguish between plains and mountain systems (for example, a strip of mountains with mountain ranges of Mendeleev, Lomonosov and Otto Schmidt in the Central Arctic), and the deepest depressions, including the Kuril-Kamchatka, the third in the world in depth , reaches 10,540 m below ocean level. The relatively shallow bottom near the Arctic seas rises above the depths of the central parts of the Arctic Ocean like a balcony, forming a continental shelf or shelf.

Plains are concentrated mainly in the western half of Russia, and plateaus, highlands and mountains predominate in the east - from the Yenisei valley to the shores of the Pacific seas. Plains make up about 60% of the territory. The two largest of them - BE and ZS - are among the greatest plains in the world. Medium-altitude mountain systems stretch like a solid barrier parallel to the coasts of the Pacific Ocean seas. In the south, along the border, there is a belt of high mountains, from which the entire territory drops to the Arctic Ocean. The largest rivers of Siberia - the Ob, Yenisei, Lena - flow to the north along this slope. And to the south from the Arctic, powerful currents of cold air pass through the plains.

The southern belt of mountains is included in the belt of high uplifts of Eurasia and consists of separate mountain systems of different ages: the Caucasus, Altai, Sayan, Baikal and Transbaikalia. The Caucasus and Altai are among the high mountains of Eurasia.

Climate is a long-term weather regime that has developed as a result of the interaction of the atmosphere with all natural and geographical factors and is subject to the influence of space and human economic activity.

The climate of Russia is formed under the influence of a number of climate-forming factors and processes. The main climate-forming processes are radiation and circulation, which are determined by the conditions of the territory.

Radiation- incoming solar radiation is an energy base, it determines the main flow of heat to the surface. The farther from the equator, the smaller the angle of incidence of the sun's rays, the smaller the amount supplied. The expenditure part consists of reflected radiation (from the albedo) and effective radiation (it increases with decreasing cloud cover, the total - from north to south).

In general, the radiation balance in the country is positive. The only exceptions are some islands in the Arctic. In winter it is negative everywhere, in summer it is positive.

Circulating... Due to the different physical properties of land and the ocean, there is unequal heating and cooling of the air in contact with them. As a result, there are movements of air masses of various origins - atmospheric circulation. It proceeds under the influence of low and high pressure centers, their position and severity change seasonally. However, in most of our country, westerly winds prevail, bringing Atlantic air masses, with which the main precipitation is associated.

The influence is especially great in winter, due to the western transport of warm and humid air masses from the Atlantic.

The large size of the territory of our country, the presence of vast valleys and large mountain systems have led to a clear zonal provincial distribution of soils, vegetation and animals. The main conditions for the formation of biocomponents are the ratio of temperature and moisture. the relief of the territory and the degree of continentality of the climate have a significant impact on their distribution.

The unity of the biocomplex is due to the zonal structure of atmospheric processes, the interaction of all components of nature and the long history of the development of the territory in the Phanerozoic.

The distribution of soils, vegetation and animals on the territory of Russia determines the law of zoning on the plains and altitudinal zoning in the mountains. Therefore, when moving along the meridians or along the slopes of mountains, due to changes in hydro-climatic conditions, there is a gradual change of some types of soil and vegetation, as well as animal complexes, by others.

But at the same time, the increasing continentality of the climate to the east (up to certain limits) and the different geological history of large geostructures (platforms and folded belts) led to the differentiation of soils, vegetation and fauna, i.e. to the manifestation of provinciality (sector).

The peculiarities of the territory orography are predetermined by the complex geological history and various geological structures. Large lowlands, plains and plateaus correspond to platforms, and mountain structures correspond to folded belts.

The territory of Russia is located on several lithospheric plates: the northern part of the Eurasian, the western part of the North American, the northern part of the Amur. And only the Okhotsk plate is almost entirely located on the territory of the country.

The earth's crust within Russia, as elsewhere on Earth, is heterogeneous and uneven in age. It is heterogeneous both in plan and in vertical direction.

More rigid, stable parts of the earth's crust - platforms - differ from the more mobile ones - folded belts, which are more susceptible to both compression and vertical swing. As a rule, the platforms are characterized by a two-tier structure, where a crushed crushed base and a cover of horizontal layers covering it are distinguished.

The most ancient platforms are the Precambrian. Their foundation is not only complicated by the oldest rocks, which are more than 570-600 million years old, but was also crumpled into folds before the strata of subsequent eras appeared. This is the structure of our two vast platforms, which are among the largest in the world.

In those parts where the oldest structures of the Earth were not flooded with seas, or where marine sediments were eroded in subsequent eras, an ancient foundation - the so-called shields - comes to the surface. There are also underground outcrops of the basement, which are close to the surface (Voronezh crystalline massif). Don only in one place reached its vault.

Stable platforms increased in size over time - sections of neighboring folded zones were soldered to them, which acquired rigidity in the process of crushing. At the end of the Precambrian era, i.e. 500-600 million years ago, the Baikal folding sharply increased the Precambrian core of the future Siberian platform: huge folded massifs of the Baikal region and parts of Transbaikalia joined the Aldan shield.

During the Paleozoic era, powerful folding shook the earth's crust twice. The first, called the Caledonian folding, took place in several stages in the Early Paleozoic, 300-400 million years before the present day. The folds in the center of the Sayan Mountains remained his monuments. The second, called the Hercynian folding, took place in the Late Paleozoic (200-250 million years ago) and turned a huge trough of the earth's crust between the Russian and Siberian platforms into the Ural-Tien Shan fold zone. As a result of this folding, the Russian and Siberian platforms merged into an integral continent - the basis of the future Eurasia.

In a wide belt adjacent to the Pacific Ocean, the main stage of crustal collapse was the Mesozoic era - 60-190. its structures, called the Pacific ones, extended the Siberian platform from the east, forming powerful folded areas in Primorye, Amur, Transbaikalia and in the northeast of Siberia.

After the Mesozoic movements, only two vast strips, where a restless regime remained, did not lose their pliability to crumples. One stretched across the Alps and the Caucasus to the Himalayas. The second strip, bordering the east of Asia and including the western outskirts of the Pacific Ocean, is the East Asian fold region. Both areas continued to exist not only in the Mesozoic, but also later. It was in the Cenozoic, i.e. in the last 60 million years, they have been the scene of powerful collapses. The last of the folds, the Alpine, developed here, during which the bowels of the Caucasus, Sakhalin, Kamchatka and the Koryatsky Upland were crushed. These active areas continue to exist today, showing their activity by numerous earthquakes, and volcanism in the East Asian mountain-island arcs.

In the second half of the Alpine era of folding - in the Neogene, 10-20 ml. years ago, a completely new stage in the history of the earth's crust began, which was of particular importance for the modern relief. It is associated with the latest, or neotectonic movements, mainly vertical uplifts and subsidences, which encompassed not only the alpine mobile zones, but also structures of various ages that are significantly distant from them.

The youngest folded zones, the Caucasus, Sakhalin and the Kuril-Kamchatka arc, have been very intensely affected. All these mountainous countries exist now not so much as a result of recent folding, but as a result of the recentness and intensity of these recent vertical uplifts. In the general diagonal belt of mountains, structures of different ages were involved in the uplift, such as the Precambrian (south of the Aldan Shield, Baikalids of the Stanovoy Range and Highlands), Paleozoic (Hercynides of Altai, Urals), Mesozoic (northeast Asia). Recent movements were expressed not only in uplifts, but also in lowering. Depressions of the earth's crust have created the modern appearance of the depressions of the seas and large lakes, many lowlands and depressions (Baikal). The piedmont depressions adjacent to the young mountains underwent especially strong diving.

The stability of the platforms in relation to crushing does not mean immobility in general. Both platforms and folded areas are subject to a different type of movement - alternating vertical vibrations (concepts and descents).

The relationship between the relief and the structure of the earth's crust is approximately as follows: the higher the surface, the greater the thickness of the crust. The largest is where the mountain formations are (40-45 km), the smallest is the basin of the Sea of ​​Okhotsk. Isostatic equilibrium. At the contact of the Eurasian and North American plates, the plates move apart (Momsky rift) and a zone of diffuse seismicity is formed. The latter is also typical for the margin of the Okhotsk plate. At the contact between the Eurasian and Amur regions, there is also a separation - the Baikal rift. Okhotomorskaya at the contact with the Amurskaya (Sakhalin and the Sea of ​​Japan), the convergence of plates is 0.3-0.8 cm per year. The Eurasian is bordered by the Pacific, North American, African (Arabian) and Indian (Hindustan-Pamir). The compression belts of the lithosphere between them are Alpine-Asian in the south and Tsirkum-Pacific in the east. The edges of the Eurasian Plate are active in the east and south and passive in the north. In the east - the submersion of the oceanic under the mainland: the junction zone consists of marginal seas, island arcs and a deep-sea trench. In the south, there are mountain ranges. Passive margins in the north - a huge shelf and a distinct continental slope.

Eurasia is characterized by linear and ring structures, established according to satellite imagery data, geological-geophysical and geological studies. seismic cores of the continental crust. Nuclear, 14.

The heat flow of the Earth on the territory of Russia has different meanings: the smallest values ​​are on ancient platforms and the Urals. Elevated - on all young platforms (slabs). The maximum values ​​are folded belts, the Baikal rift, marginal TO seas.

With depth, the temperature in the Earth gradually increases. Under the oceanic plates, the temperature of the mantle reaches the melting point of the mantle rocks. Therefore, the surface of the beginning of melting of mantle material is taken as the base of the lithosphere under the oceans. Below the oceanic lithosphere, the mantle material is partially molten and plastic with reduced viscosity. The plastic layer of the mantle stands out as an independent shell - the asthenosphere. The latter is clearly expressed only under the oceanic plates, practically absent under the thick continental plates (basaltic magmatism). In the boundaries of the continental plates, it can manifest itself only when the hot mantle matter, due to the split of the plate, can rise to the level of the beginning of melting of this matter (80-100 km).

The asthenosphere has no ultimate strength and its substance can deform (flow) under the action of even very small excess pressures, although very slowly due to the high viscosity of the asthenospheric substance (about 10 18 - 10 20). For comparison, the viscosity of water 10 -2, liquid basaltic lava 10 4 - 10 6, ice - about 10 13 and rock salt - about 10 18.

The movements of lithospheric plates over the asthenosphere surface occur under the influence of convective currents in the mantle. Individual lithospheric plates can diverge, approach, or slide relative to each other. In the first case, tension zones with rift cracks appear between the plates along the boundaries of the plates, in the second, compression zones accompanied by the thrust of one of the plates onto the other, in the third, shear zones, transform faults, along which the neighboring plates are displaced.

As the main categories of tectonic regions, we will single out: 1. relatively stable regions - ancient platforms, mainly with a pre-Upper Proterozoic metamorphic basement, 2. mobile mobile belts of the Neogean, consisting of folded regions of different ages (in the place of dead geosynclinal regions) and modern geosynclinal regions, 3.areas, transitional - metaplatforms.

Ancient platforms, or cratons, represent vast areas of the ancient continental crust, measured in millions of square kilometers, largely formed in the Archean and almost entirely by the end of the Early Proterozoic. Neogei is a relatively calm tectonic regime: "sluggishness" of vertical movements, their weak differentiation in area, relatively low rates of uplifts and subsidence (less than 1 cm / thousand years). At the early mega-stage of development, most of their area was uplifted, and the subsidence mainly involved narrow linearly elongated graben-like depressions - aulacogenes. At a later, plate mega-stage (phanerozoic), a significant area of ​​platforms was drawn into the subsidence, on which a cover of almost undisturbed sediments was formed - a plate. Simultaneously with the sinking of the basement, the regions of the platforms were isolated within the limits of the plates, which for most of their history had a tendency to uplift and represent vast protrusions of the ancient basement - shields.

The cover of ancient platforms usually does not bear traces of metamorphic changes, which, like the absence or limited development of manifestations of magmatism, is explained by a significant decrease in the thermal regime during the formation of ancient platforms and, as a rule, by a low heat flow in most of their territory (except for aulacogens). However, in some zones of ancient platforms, manifestations of magmatism took place, and in some rare phases, due to anomalous heating of the upper mantle beneath them, ancient platforms could become the arena of powerful trap magmatism in effusive and intrusive forms.

Movable belts... They were founded mainly in the ancient Proterozoic. In its development, 2 mega-stages pass: geosynclinal (the greatest tectonic mobility, expressed in differentiated horizontal and vertical movements and a high, albeit inconsistent thermal regime in the crust and upper mantle) and postgeosynclinal (in place of dead geosynclinal belts, activity is reduced, but much more, than on ancient platforms).

The total duration of the goesynclinal process is 1-1.5 billion years, but in some areas it ends earlier. “Cycles”, the geosynclinal stage proper and the shorter orogenic stage (orogenesis) are distinguished.

Actually geosynclinal: stretching of the crust, the emergence of elongated graben-like depressions. Wide deflections break up into narrow ones. At the end there is actually a hesinkle. stages stop lowering. At the beginning of the orogenic stage, they undergo severe compressive deformations (from the inner zones to the periphery). They turn into folded structures. During the orogenic stage, they experience a gradually increasing uplift, not completely compensated by denudation, and at the late orogenic stage they turn into mountain structures. Thus, there is a complete reversal of the tectonic plan (geosynclinal troughs into mountain rises). At the same time, in the zones of growing folded structures, edge deflections appear to compensate for their uplift, in the rear - internal deflections or depressions filled with debris.

The "cycles" into which the process of development of geosynclinal belts breaks down end with a relative hardening of the crust, acquiring the features of a typical (mature) continental type crust over a significant (or entire) area. At the beginning of the next "cycle", this crust is partially destroyed and the geosynclinal regime is regenerated, while other areas are excluded from the further geosynclinal process.

In most of the North Atlantic mobile belt, the geosynclinal process ended in the middle of the Paleozoic, the Ural-Mongolian - at the end of the Paleozoic - early Mesozoic, for most of the Mediterranean belt, it is close to completion, and significant parts of the Pacific belt are still at different stages of the geosynclinal process.

Metaplatform areas... Something average in the nature of tectonic structures, the degree of mobility of the crust and the peculiarities of tectonic movements. At the borders. Structurally, it is a combination of two main types of tectonic elements - mobile aulacogeosynclinal zones and relatively "rigid" metaplatform massifs separated by these zones from ancient platforms. The aulacogeosynclinal zones represent linearly elongated zones of an intermediate character between the aulacogens of ancient platforms and the geosynclinal troughs of mobile belts. In the Late Proterozoic, simultaneously with the mobile belts framing the platforms, usually branching off from the latter. Tomb-base troughs - compression - metamorphism, intrusive bodies - folded zones (Donetsk, Timanskaya).

The role of climate in human life can hardly be overestimated. It determines the ratio of heat and moisture, and, consequently, the conditions for the occurrence of modern relief-forming processes, the formation of inland waters, the development of vegetation, and the placement of plants. The peculiarities of the climate have to be taken into account in the economic life of a person.

Influence of geographic location.

Air masses and their repeatability. Three types of air masses are characteristic of Russia: arctic air, temperate air, and tropical air.

Most of the country is dominated by air masses throughout the year. moderate latitudes, represented by two sharply different subtypes: continental and marine. Continental the air is formed directly over the mainland, it is dry throughout the year, low temperatures in winter and rather high in summer. Nautical air comes from the North Atlantic, and in the eastern regions - from the northern part of To. Compared to continental air, it is more humid, cooler in summer and warmer in winter. Moving through the territory of Russia, the sea air is quickly transformed, acquiring the features of the continental.

Arctic the air is formed over the ice of the Arctic, so it is cold, has a low absolute humidity and high transparency. Influence on the northern part of the country, especially SS and NE. In transitional seasons, it causes frosts. In summer, advancing and drying up more and more, it brings droughts and dry winds (south of the BE and WS). The air that forms over the Arctic can be called continental. Only over the Barents Sea is the Arctic marine being formed.

Tropical air over the southern territories, is formed over Central Asia, Kazakhstan, the Caspian lowland, the eastern regions of the Ciscaucasia and Transcaucasia as a result of the transformation of the air of temperate latitudes. Differs in high temperatures, low humidity and low transparency. To the south of the Far East, the tropical sea air sometimes penetrates from the central regions of To, and into the Caucasus from the Mediterranean. Differs in high humidity and high temperatures.

Atmospheric fronts.

Physical and geographical conditions of the territory... The underlying surface, over which they form and acquire new properties, has a great influence. So, in winter, humid air masses bring the latent heat of vaporization to a cold surface and warming sets in. In summer, humid air masses also bring precipitation, but evaporation and a slight cooling begins on the warm underlying surface.

The influence of the relief on the climate is great: with altitude, the temperature drops for every 100 meters by 0.6 ° C (due to a decrease in the radiation balance), atmospheric pressure decreases. Affected by exposure. Mountains play an important barrier role.

Special role - sea ​​currents... Warm North Atlantic, cold around the Kuriles, Kamchatka, the Sea of ​​Okhotsk.

Climatic features of the winter period. In cold weather on the territory of Russia, from October to April, an area of ​​increased pressure (Asian maximum) is established, an area of ​​reduced pressure near the eastern coasts (Aleutian minimum) develops and the Icelandic minimum increases, reaching the Kara Sea. Differences in pressure between these main baric centers of the winter period reach the greatest values ​​and this contributes to an exacerbation of circulation processes.

In connection with the western transport, the development of cyclones and anticyclones, the circulation processes are very pronounced and they largely determine the distribution of heat and moisture. The influence of the Atlantic, the Asian maximum, the Aleutian minimum and solar radiation is clearly traced.

From the Atlantic Ocean in winter, air masses bring a large amount of heat to the mainland. Therefore, in BE and the northern half of the ZC, the temperature decreases not so much from south to north as from west to east and northeast, which is confirmed by the course of the January isotherms.

The impact of the Asian maximum is reflected in the extremely low temperature of Central Siberia, the Northeast and the position of the isotherms. In the basins, the temperature reaches -70 (the cold pole of the northern hemisphere - Oymyakon and Verkhoyansk).

In the Far East, the Aleutian minimum and the Okhotsk branch of the Arctic front predetermines cyclonic activity, which is reflected in warmer and snowy winters than on the continent; therefore, the January isotherms run parallel to the coast.

The greatest amount of winter precipitation falls in the west, where air from the Atlantic enters in cyclones. From west to east and north-east, the amount of precipitation gradually decreases.

Climatic features of the summer period. The ratio of radiation and circulation conditions changes dramatically. The temperature regime is determined by radiation conditions - the entire land is heated much more than the surrounding water areas. Therefore, from April to October, the isotherms extend almost sublatitudinally. In July, throughout Russia, the average monthly temperatures are positive.

In summer, the Azores maximum moves to the north and its eastern branch penetrates the EE plain. From it, the pressure decreases to the north, south and east. The Arctic maximum remains above the SL. Therefore, cold air moves to the inner, warmer territories of Russia, where it heats up and moves away from the saturation point. This dry air contributes to the origin of droughts, sometimes with dry winds in the southeast of the EE Plain, in the south of the WS Plain and in the north of Kazakhstan. The development of dry, clear and warm weather is also associated with the spur of the Azores maximum. Above the TO, the North Pacific maximum moves to the north (the Aleutian minimum disappears), and the sea air rushes to land. The summer Far Eastern monsoon appears.

In summer, there is also a western transfer - from the Atlantic - the largest amount of precipitation.

All air masses entering the country in summer are transformed into continental air of temperate latitudes. On atmospheric fronts (arctic and polar), cyclonic activity develops. It is most pronounced on the polar front over the EE plain (continental and maritime temperate).

The Arctic front is expressed within the Barents and Kara Seas and on the coast of the eastern seas of the North Caucasus Region. Along the line of the Arctic front, cyclonic activity intensifies and causes prolonged drizzling rains in the subarctic and arctic belts. In summer, the maximum precipitation falls, which is associated with increased cyclonic activity, moisture content of air masses and convection.

Radiation and circulation conditions change in spring and autumn. In the spring, the negative radiation balance turns into a positive one, and vice versa in the fall. In addition, the position of the high and low pressure regions, the type of air masses, and, consequently, the position of the atmospheric fronts change.

General features of the bottom topography of the World Ocean

The most general idea of ​​the nature of the bottom topography of the World Ocean is given by the bathygraphic curve. It shows the distribution of the ocean floor area at different depth levels. Studies in the Atlantic, Pacific and Indian Oceans have shown that from 73.2 to 78.8% of the ocean floor area lies at depths from 3 to 6 km, from 14.5 to 17.2% of the ocean floor - at depths from 200 m to 3 km, and only 4.8-8.8% of the oceans are less than 200 m deep.

The Arctic Ocean differs sharply from all other oceans by the structure of the bathygraphic curve. Here, the bottom space with depths less than 200 m occupies 44.3%, with depths from 3 to 6 km only 27.7%.

Depending on the depth, the ocean is usually divided into the following bathymetric zones:

littoral or coastal, limited to depths of several meters;

nerite - to depths of about 200m;

bathyalny - with depths of up to 3 km;

abyssal with depths from 3 to 6 km;

hypabyssal with depths of more than 6 km.

The boundary depths of these zones are rather arbitrary. In some specific cases, they can move strongly. For example, in the Black Sea, the abyssal begins at a depth of 2 km

In fact, the bathygraphic curve cannot serve as a source for obtaining an idea of ​​the main elements of the relief of the seabed of the World Ocean. But since the time of G. Wagner (from the end of the 19th century), a tradition has been established to identify various sections of this curve with the main relief elements at the bottom of the World Ocean.

At the bottom of the World Ocean, the largest elements are distinguished, which include geotextures or planetary morphostructures:

underwater outskirts of continents;

transition zones;

ocean bed;

mid-ocean ridges.

These major elements are distinguished on the basis of fundamental differences in the structure of the relief of the solid earth's surface and various types of the earth's crust.

The planetary morphostructures of the World Ocean bottom, in turn, are subdivided into morphostructures of the second order:

The underwater outskirts of the continents are:

from the shelf;

continental slope;

continental foot.

Transition zones are divided into transition zones, each of which is represented by:

the basin of the marginal sea;

island arc;

deep-sea gutter.

The ocean bed consists of:

from oceanic basins of various types;

oceanic uplifts of various types.

Mid-ocean ridges are subdivided:

to rift zones;

flank zones.

Submarine outskirts of continents

The shelf is a relatively flat, shallow part of the ocean floor. It is adjacent to the sea or ocean. Sometimes the shelf is called a continental shelf. It is cut through by numerous flooded river valleys, half-buried by later bottom sediments. Various traces of relief-forming activity of glaciers are found on the shelves located in the zone of Quaternary glaciers: polished rocks, "sheep's foreheads", marginal moraines.

Ancient continental deposits are widespread on the shelves. All this testifies to the recent existence of land on the shelf.

Thus, the shelf was formed as a result of the recent flooding of the former coastal land with ocean waters. The flooding occurred as a result of the rise in the level of the World Ocean after the end of the last glaciation.

The activities of modern relief-forming agents take place on the shelf:

abrasion and accumulative activity of sea waves;

tidal activity;

activity of coral polyps and calcareous algae of tropical and equatorial seas.

Of particular interest are the wide shelves adjacent to the vast coastal plains. Oil and gas fields are discovered and developed within the plains. Often these deposits continue to the shelf. At present, there are many examples of intensive development of such deposits. All this indicates the common geological structure of the shelf and adjacent land.

Fish resources of the shelf are of no less practical interest. The shelf resources are large in terms of stocks of building materials.

Continental slope. The shelf from the ocean side is outlined by a morphologically pronounced boundary - the edge of the shelf (a sharp bend in the profile). A sharp increase in the steepness of the bottom immediately begins behind the edge of the shelf - a bottom zone with steep slopes. This zone can be traced within the depths of 100-200 m and up to 3-3.5 km, and is called the continental slope.

The characteristic features of the continental slope are:

deep transverse, in relation to its longitudinal profile, dissection by valley-like forms - underwater canyons. The underwater canyons are believed to be of complex origins. The primary forms of the canyons are formed under the influence of tectonic faults. Secondary forms are formed as a result of the action of turbidity currents on the primary forms. Turbidity streams develop pre-existing canyons. Turbidity flows are flows of a suspension of suspended sedimentary material moving under the influence of gravity.

frequent stepped profile. The continents as a whole are characterized by ascending vertical movements of the earth's crust, and the ocean floor - sagging, sinking. The result is a stepped continental slope profile. On the continental slope, gravitational processes such as underwater landslides and creeps take place. The gravitational processes on the continental slope together represent the most important mechanism for the movement of sedimentary material from the shelf and the upper part of the continental slope to great depths. The movement of sedimentary material along a stepped slope is carried out as follows: sedimentary material reaches a step, accumulates as much as possible, and then it is discharged to a step. Such a picture is typical, for example, for the Patagonian shelf in the Atlantic Ocean. Moreover, individual steps of the continental slope can be highly developed in width. They are called edge plateaus.

often encountered monoclinic structure of the continental slope. In this case, the continental slope turns out to be folded by a series of inclined sedimentary layers. The layers consistently build up the slope and thereby cause it to move towards the ocean. Recently, it has been found that the continental slope has an abundant living population. Many commercial fish are caught on the continental slope.

The continental foot is the largest accumulative form of the ocean floor.

Usually it is a wavy, inclined plain that adjoins the base of the continental slope. Its origin is associated with the accumulation of huge masses of sedimentary material and its deposition in a deep deflection of the earth's crust. Sedimentary material moves here under the influence of gravitational processes and currents. Thus, the trough turns out to be buried under these sediments. Where the amount of precipitation is especially high, the outer boundary of the “lens” of precipitation is extended into the ocean floor. As a result, the oceanic crust is already buried under the sediments.

The activity of bottom abyssal currents is also confined to the continental foot. These currents form the deep bottom water masses of the ocean. Abyssal currents move huge masses of semi-suspended sedimentary material in the zone of the continental foot. Moreover, this movement occurs parallel to the base of the continental slope. Large masses of precipitation fall out of the water column along the path of the currents. This material is used to build huge bottom accumulative landforms - sedimentary ridges.

In other cases, between the base of the continental slope and the ocean floor, instead of a mountain-hilly relief, there is a narrow deep depression, with a bottom leveled under the influence of accumulation.

Taken together, the underwater margin of the continental slope can be regarded as a gigantic mass of "continental terrace". In turn, this terrace is the concentration of sedimentary material on the ocean floor. Due to the accumulation of sediments, this terrace tends to move out into the ocean and "creep" to the peripheral areas of the oceanic crust.

Since continents are protrusions of the earth's surface, that is, three-dimensional bodies, the continental shelf can be considered as a part of the continental surface, flooded by the waters of the ocean. The continental slope is like a slope, the "end" of a continental block. Moreover, the continental slope and the continental shelf are morphologically a single system. The continental foot also gravitates towards this system. Thus, together they form a first-order morphostructure - the underwater margin of the continents.

Transition zones

In most of the periphery of the Atlantic, Indian and the entire Arctic oceans, the underwater margins of the continents are in direct contact with the ocean floor.

On the periphery of the Pacific Ocean in the Caribbean and Scotia Seas, as well as on the northeastern edge of the Indian Ocean, more complex systems of transition from continent to ocean have been identified. Along the entire length of the western edge of the Pacific Ocean, from the Bering Sea to New Zealand, an extensive transition zone lies between the underwater margins of the continents and the ocean floor.

In the most typical form, the transition zones are presented as a complex of three large relief elements:

depressions of the marginal seas;

island arcs - mountain systems separating the basins of the marginal seas from the ocean and crowned with islands;

deep-sea trenches - narrow, very deep depressions (depressions), usually on the outer side of island arcs. Moreover, the depressions are characterized by the greatest depths of the oceans.

Depressions of the marginal seas. The seas are usually deep. Often in the seas the bottom is uneven and abounds in mountains, hills, hills. The thickness of sediments in such seas is not great.

In other seas, the bottom is ideally leveled, and the thickness of sediments exceeds 2-3 km. Moreover, it is the sediments that level the relief by burying the fundamental irregularities.

The earth's crust under the basins of the marginal seas is suboceanic.

Island arcs are sometimes crowned with volcanoes. Many of them are active. More than 70% of active volcanoes are confined to island arcs. The largest of the ridges protrude above sea level and form islands (for example, the Kuril Islands).

There are transition areas in which there is not one, but several island arcs. Sometimes arcs of different ages merge with each other, forming large tracts of island land. Such massifs, for example, are characteristic of the islands of Sulawesi and Halmager. The largest island massif is the Japanese island arc. Under such large island massifs, continental-type crust is often found. The most important feature of the transition zone is a high degree of seismicity.

There are epicenters:

surface earthquakes (30-50 km). They are concentrated mainly in the deep-sea trenches and on the outer edge of the island arcs;

mid-focus earthquakes - 300-50 km;

deep focus earthquakes - more than 300 km deep. These epicenters are found mainly in the deep-water basins of the marginal seas.

All sources of earthquakes are confined to some zones extending from the Earth's surface into its bowels. These zones are called the Benioff-Zavaritsky zones. They go under the marginal seas or even under the outskirts of the mainland and are inclined at an angle of 30-60º. These are zones of increased instability of the substance that composes the Earth. They penetrate the earth's crust, the upper mantle and end at depths of up to 700 km.

Thus, the transition zones are distinguished by sharp contrasts of depths and heights, as well as an abundance of volcanoes.

The transitional zones are characterized by the geosynclinal type of the earth's crust.

Ocean bed

The relief of the ocean floor is characterized by a combination of:

vast basins;

uplifts separating these basins.

Basins of the ocean floor. The bottom of the hollows is almost everywhere characterized by an increased distribution of hilly relief - the relief of abyssal hills. Abyssal hills are submerged elevations ranging from a few meters to 500 m in height. In diameter, the hills range in size from 1 to several tens of kilometers. Abyssal hills form clusters at the bottom of the hollows, which occupy large areas. Almost everywhere, the abyssal hills are cape-like covered with bottom sediments.

Where the thickness of precipitation is great, the hilly relief is replaced by undulating abyssal plains.

Where the sediments completely bury the irregularities of the bedrock, flat abyssal plains are formed. They occupy no more than 8% of the bottom area of ​​the basins.

Seamounts rise above the bottom of the hollows. These are detached mountains with a predominantly volcanic origin. Some of them are so high that their peaks protrude above the sea level and form volcanic islands.

In some places, valleys are found within the limits of the bed. Their length can reach several thousand kilometers. Their formation is associated with the activity of bottom currents and turbidity flows.

The ocean floor uplifts are not uniform. Most of the uplifts are linearly oriented and it is customary to call them oceanic (but not mid-oceanic) ridges. Morphologically, oceanic ridges are subdivided:

on oceanic shafts (vaulted shafts);

arched-block ridges;

blocky ridges.

In addition to ridges, oceanic uplands are distinguished in the ocean floor uplifts. They differ:

large width of the top surface;

relative isometricity of outlines.

If such an elevation along the edges of the sharply expressed scarps, then it is called an oceanic plateau (for example, the Bermuda plateau in the Atlantic Ocean).

There are no earthquakes on the ocean floor. However, in some ridges and even in isolated mountains, modern volcanism is manifested.

A characteristic feature of the relief and tectonics of the ocean floor are zones of oceanic faults. These include:

blocky (horst) ridges, linearly located landforms;

depressions-grabens, stretching for hundreds and thousands of kilometers. They form deep oceanic troughs that cut rift and flank zones of mid-ocean ridges.

Mid ocean ridges

Mid-ocean ridges were identified in the 50-60s of the last century. The mid-ocean ridge system stretches across all the oceans. It begins in the Arctic Ocean, continues in the Atlantic Ocean, goes into the Indian Ocean and passes into the Pacific Ocean. The study of the relief of this system shows that, in essence, it is a system of uplands, consisting of a number of ridges. The width of such a highland can reach 1000 km. The total length of the entire system exceeds 60 thousand km. In general, this is the most grandiose mountain system on Earth, which has no equal on land.

In the mid-oceanic ridges, there are rift and flank zones.

The axial part of the system is characterized by a rift structure. It is broken by faults of the same origin as the ridge. In the axial part proper, these faults form depressions - rift valleys. Rift valleys intersect with transverse troughs that are confined to transverse fault zones. In most cases, the trenches are deeper than rift valleys. The gutters are characterized by maximum depths.

On both sides of the rift zone, the flank zones of the system extend. They also have mountainous relief, but less dissected and less sharp than in the rift zone. The peripheral part of the flanking zones is characterized by a low-mountain relief, which gradually turns into a hilly relief of the ocean floor.

The mid-ocean ridges are also characterized by volcanism and a high degree of seismicity. Here, only surface earthquakes are widespread with source depths of no more than 30-50 km.

The mid-oceanic ridges are characterized by special features of the structure of the earth's crust. Under the sedimentary layer of variable thickness in the mid-oceanic ridges, there is a layer of the earth's crust that is denser than basalt. Studies have shown a wide distribution of rocks inherent in the Earth's mantle. In this regard, a hypothesis of plate tectonics, a hypothesis of growth (“spreading”) of the oceanic crust and huge displacements of lithospheric plates in the zone confined to the mid-ocean ridges arose. Thus, the type of crust for the zone of mid-oceanic ridges is called riftogenic.

The southern continents are conventionally called not only Australia and Antarctica, which are completely in the Southern Hemisphere, but also Africa and South America, partially located in the Northern Hemisphere. All four continents have a common history of the development of natural conditions - they were all part of a single continent of Gondwana.

Geographical position. Consideration of the geographical position of the continent always precedes its study. What is geographic location? This is essentially the address of the mainland. And its nature depends on which part of the earth's surface the continent is located in. If it is located near the pole, naturally, there will be harsh natural conditions, and if it is near the equator, then it will have a hot climate. The amount of solar heat and precipitation received, their distribution over the seasons depends on the geographical location.

You know from the previous course in geography: to determine the position of any geographic object on the surface of the Earth, you need to know its geographic coordinates. First of all, they determine the extreme northern and southern points of the continent, that is, they find out in what latitudes it is located. Also important is the position of the mainland in relation to the initial meridian, its extreme western and eastern points. The extent of the ocean's influence, the continentality of its climate, and the variety of natural conditions depend on the length of the continent from west to east. The proximity of other continents and the surrounding oceans are also important. (For a plan of characterizing the geographical position of the mainland, see the appendix.)

The peculiarities of the geographical position of the southern continents are that three continents: South America, Africa and Australia are located near the equator, therefore high temperatures prevail in most of the territory all year round. Only a narrow southern part of South America reaches temperate latitudes. Most of the continents are located in the subequatorial and tropical zones. Antarctica is the only continent of the Earth that is located around the South Pole, which determines the exceptional severity of its nature.

Thus, the geographical position caused great contrasts in the nature of the southern continents: from eternal summer to eternal winter.

1. Using the plan, determine the geographical position of the island of Madagascar.
2. The largest desert in the world is located in the northern part of Africa. What influence do you think the geographical position of the mainland has on her education?

General features of the relief. As you already know (see the topic "Lithosphere and the relief of the Earth"), the northern and southern continents developed in different ways. Since the southern continents were once a single continent, they share similar natural features.

A close examination of the physical map of the world and individual continents allows us to highlight several common features of the relief of all four continents:

1. In the relief of all continents, two main parts stand out - vast plains and mountains.
2. Most of the continents are plains located on platforms.
3. Various mountain systems are located on the outskirts of the continents: the Andes in South America in the west, Atlas in Africa in the northwest, the Great Dividing Range in Australia in the east. These mountains, as it were, surround the former plains of Gondwana. The structure of the plains of the modern continents has much in common. Most of them are formed on ancient platforms, formed at the base of crystalline and metamorphic rocks.

In addition to relatively flat areas on the plains, there are territories where ancient crystalline rocks of the platform base protrude to the surface. On these ledges, blocky mountains and highlands were formed in the form of horst uplifts. Troughs of platforms, covered with sedimentary rocks, are represented in the relief by vast depressions, some of which are low-lying plains.

What are the reasons for the collapse of Gondwana into separate continents? Scientists believe that about 200 million years ago, the internal forces of the Earth (the movement of matter in the mantle) led to the split and expansion of a single continent.

There is also a hypothesis about the cosmic reasons for the change in the external appearance of our planet. It is believed that the collision of an extraterrestrial body with our planet could cause a split of the giant land, the expansion of sections of the lithosphere, the rise and fall of individual sections, which were accompanied by the outpouring of basaltic lavas. In the spaces between the individual parts of Gondwana, the Indian and Atlantic oceans gradually formed, and where the lithospheric plates collided with other plates, folded mountain regions were formed.

Mineral deposits are closely related to the geological history, the composition of rocks and the relief of the continents. All southern continents are rich in them. Deposits of ferrous and non-ferrous metal ores (copper, lead, zinc, nickel, etc.), diamonds, noble and rare metals are associated with the close occurrence of the crystalline basement of the platforms and its outcrops. Their deposits are located both on the plains and in the mountains.

Plains, composed of sedimentary rock strata, are rich in deposits of oil, natural gas, phosphorites, bituminous and brown coal. Geologists conducting exploration of deposits use data on the unity of the structure of the relief of the continents. Over the past decades, in similar geological conditions, for example, oil fields have been found off the western coast of Africa and at approximately the same latitudes off the eastern coast of South America.

1. Using the plan of characteristics of the geographical position of the continent (ocean), explain the importance of each point of the plan.
2. What are the patterns of the location of mountains and vast plains on the surface of the Earth and how is this manifested on the continents of the Southern Hemisphere?

A general idea of ​​the distribution of ocean depths is given by bathygraphic curves of the World Ocean as a whole and of individual oceans (Fig. 19.1). Comparison of these curves shows that the distribution of depths in the Pacific and Atlantic oceans is almost the same and follows the same patterns as the distribution of depths throughout the World Ocean. From 72.3 to 78.8% of the ocean floor area lies at depths from 3000 to 6000 m, from 14.5 to 17.2% - at depths from 200 to 3000 m, and only from 4.8 to 8.8% of the area oceans have depths less than 200 m. Corresponding figures for the World Ocean are 73.8; 16.5 and 7.2%. The Arctic Ocean is sharply distinguished by the structure of the bathygraphic curve, where the bottom space with depths of less than 200 m occupies 44.3%, and the depths most characteristic of all oceans (i.e., from 3000 to 6000 m) are only 27.7%. Depending on the depth, the oceans are usually divided into bathymetric zones: littoral, i.e. coastal, limited by depths of several meters; nerite- to depths of about 200 m; bathyal- up to 3000 m; abyssal- from 3000 to 6000 m; hypabyssal depth - more than 6000 m.

According to modern concepts, the ocean floor, according to the most characteristic features of its structure, is divided into underwater continental margins, a transition zone, an ocean floor and mid-ocean ridges.

Submarine continental margins divided into shelf, continental slope and continental foot (Fig. 19.2).

Shelf (continental shelf) adjoins directly to land, extending to a depth of 200 m. Its width varies from the first tens of kilometers to 800-1000 km in the Arctic Ocean. This is a shallow part of the sea with a relatively flat surface, the slope of which is generally about 1 °. Submarine river valleys, flooded sea terraces and ancient coastlines are often observed on the shelf surface. The shelves have a continental-type crust with a three-layer structure (sedimentary, granite-gneiss and basalt layers).

Mainland (continental) slope extends from the outer edge of the shelf, called by the edge, to depths of 2-2.5 km, and in some places up to 3 km. The slope of the slope surface is on average 3-7 °, but sometimes it reaches 15-25 °. The relief of the continental slope is often characterized by a stepped structure, characterized by alternating scarps with steep slopes - up to 25 °, with sub-horizontal steps, which, apparently, is associated with tectonic ruptures.

In many places, the continental slope is cut by deep K-shaped hollows with steep sides - canyons... Part of them is the continuation of the mouths of such rivers as the Congo, Indus, Hudson (see Fig. 19.2), Colombia. The mechanism of canyon formation is associated with the erosional activity of turbidity streams; erosional activity of the rivers that drained the continental margins during the epoch of lowering of the sea level; discontinuous tectonics.

Continental foot is an intermediate element between the continental slope and the ocean floor and is a hollow sloping plain tens and hundreds of kilometers wide, extending to depths of 3500 m and more. The thickness of sediments at the foot in some places reaches 5 km or more, which is the result of the removal of material by turbidity flows and the gravitational transport of sediments from the continental slope.

Among the underwater continental margins, according to the features of the relief and articulation with the continent, tectonic activity and the nature of magmatism, the following types are distinguished: passive (Atlantic) type and active, which include two:

a) Western Pacific;

b) Andean Pacific.

Passive (Atlantic) type. These margins are formed as a result of the fracture of the continental crust during rifting and its pushing apart in opposite directions as the oceanic bed grows. A rift zone can be represented by a single graben or a system of grabens. The relief of the margins is gentle due to weak tectonic activity and intense accumulation of sediments, in the formation of which a significant proportion is made by extensive fan fans. The most noticeable morphological boundary is the bend from the shelf to the continental slope (shelf edge). Limestone barrier reefs that form at the beginning of the continental slope can play an important role.

In the early stages of the formation of the margins, the introduction of large intrusive bodies of basic composition is possible. The nature of the junction with the continent is calm, gradual, without a sharp difference in depths and slopes: continent -> shelf -> continental slope -> continental foot -> ocean floor (see Fig. 19.2). These margins are characteristic of the North and South Atlantic, the Arctic Ocean and a large part of the Indian.

Active (Andean) type characterized by a sharp contrast of the relief, due to the combination of the highest Andean ridge, the absolute marks of which reach almost 7000 m and the deep-water (6880 m) Peruvian-Chilean trench, crowned with a chain of young volcanoes that form the Andean volcanic belt. The following transition is observed here: a continent with a volcanic belt -> a sedimentary terrace and a continental slope adjacent to the continent -> Peruvian-Chilean trench.

The Andes are distinguished by an unusually high seismicity and are the arena of intense volcanism.

Active (Western Pacific) type characterized by a different transition from the continent to the ocean floor: continent -> depressions of the marginal seas (Okhotsk, Japanese, etc.) -> island arcs (Kuril, Japanese, etc.) -> deep-sea trenches (Kuril-Kamchatka, etc.) -> bed ocean. Essentially the entire Pacific Ocean is accompanied by margins of this type. They are characterized by high seismicity with a concentration of earthquake foci at depths above 250-300 km, active volcanic activity with explosive eruptions. Known catastrophic eruptions are associated with island volcanic arcs: Krakatoa, Mont Pele, Bezymyanny, St. Helles, etc.

The volume of ejection of volcanic material during catastrophic eruptions is enormous: from 1 to 20 km3, capable of covering an area of ​​500-600 km2 and being carried far into sea basins, with the formation of tongues of foreign tuffaceous-clastic material among normal pelagic and terrigenous sediments.

Transition zone is located on the ocean side of the underwater continental margins and includes the basins of the marginal seas separating them from the open ocean, island arcs and deep-sea trenches elongated along their outer edge. These zones are distinguished by an abundance of volcanoes, sharp contrasts of depths and heights. The maximum depths are confined precisely to the deep-sea trenches of the transition zones, and not to their own ocean floor.

Deep sea trenches- the deepest depressions in the world: Mariana - 11022 m, Tonga - 10 822 m, Philippine - 10 265 m, Kermadek - 10047 m, Izu-Boninsky - 9 860 m, Kuril-Kamchatsky - 9 717 m, Northern Novo-Hebrides - 9 174 m, Volcano - 9 156 m, Bougainvillea - 9 103 m, etc.

Deep-sea trenches are especially widespread in the Pacific Ocean, where in its western part they form an almost continuous chain stretching along island arcs from the Aleutian, Kuril-Kamchatka to New Zealand and developing within the Philippine-Marian expansion. These are narrow and deep up to 9-11 km ditches of an asymmetric structure: the sharp slopes of the troughs are very steep, in places they descend in almost vertical ledges, elongated along the strike of the trenches. The height of the ledges is 200-500 m, the width is 5-10 km, and the oceanic slopes are more gentle, separated from the adjacent oceanic basins by a low, gentle swell and covered with a thin layer of sediments. The bottoms of the troughs are narrow, rarely reaching a width of 10-20 km, mostly flat, gentle, sometimes parallel uplifts and troughs are found on them, and in some places they are separated by transverse rapids that impede the free circulation of water. The sediment cover is extremely thin, no more than 500 m, in some places it is completely absent and lies horizontally.

The earth's crust within the transition zone has a mosaic structure. There are areas of the earth's crust of continental and oceanic types, as well as transitional crust (subcontinental and suboceanic).

Island arcs- these are mountain structures protruding above sea level with their peaks and ridges, forming islands. The arcs have a convex shape and their convexity is directed towards the ocean. There are exceptions: the New Hebrides and Solomon arcs are convex to the Australian continent. Island arcs consist of some volcanic accumulations (Kuril, Marian) or contain remnants of former arcs in their basement, or ancient crystalline strata (Japanese arc).

An important distinguishing feature of island arcs is their very high seismicity. It was found that earthquake foci are concentrated in a narrow (no more than 100 km) zone sloping obliquely from the deep-water trench under the island arc. This deep seismic-focal zone is called the Vadati-Zavaritsky-Benioff zone (VZB).

Marginal seas are located in the rear of the island arcs. Typical examples of such seas are the Okhotsk, Japanese, Caribbean and others. The seas consist of several deep-water basins with a depth of 2 to 5-6 km, separated by shallow-water uplifts. In some places, deep-sea basins are adjoined by vast shelf spaces. Deep-sea basins have a typical oceanic crust, only the sedimentary layer is sometimes thickened up to 3 km.

World Ocean Bed. The area of ​​the bed occupies 194 million km2, which is more than 50% of the surface of the World Ocean, and is located at depths of 3.5-4 to 6 thousand km. Basins, mid-ocean ridges and various heights are distinguished within the bed. Plains are confined to the bottom of the ocean floor hollows, which, due to their hypsometric position, are usually called abyssal (abyssal is an area of ​​the ocean, the depth of which exceeds 3500-4000 m). Abyssal plains are the flat and deepest (3000-6000 m) areas of the ocean floor filled with sediments of turbidity flows, as well as pelagic sediments of chemogenic and organogenic origin.

Among the oceanic basins, two types are distinguished by the bottom topography: flat abyssal plains, most developed within the Atlantic Ocean; hilly abyssal plains, developed mainly in the Pacific Ocean.

The hills- these are projections of the bottom surface with a height of 50 to 500 m and in diameter - from several hundred meters to several kilometers. The slopes of the hills are gentle - 1-4 °, rarely - 10 °, the tops are usually flat. According to the American researcher G. Menard, the hills are either small laccoliths (mushroom-like intrusions of magma), or small volcanoes or even cinder cones covered by deep-sea sediments.

Guyots, volcanic underwater mountains with flat peaks, are widespread in the Pacific Ocean. According to A. Allison et al., Some of them are very large: the Horaizn guyot is 280 km long and 66 km wide. These volcanic mountains have acquired a truncated shape as a result of wave erosion. Nowadays, their tops are located at depths of 1000-2000 m, which, apparently, is associated with the tectonic subsidence of the ocean floor. The subsidence of the ocean floor is confirmed by drilling data on atolls, where coral reef rocks were uncovered at depths from 338 to 1400 m. Currently, corals live at shallow depths of 50-60 m.

Mid ocean ridges represent a planetary system of underwater mountain ranges, with a total length of about 61,000 km (see Fig. 18.1). In the Atlantic and Indian Oceans, they extend through the central parts, and in the Pacific and Arctic they are displaced to the marginal parts. Their height reaches 3000-4000 m, width - from 250 to 2000 km, sometimes they protrude above the ocean surface in the form of islands. Narrow rift valleys (from the English rift - gorge) stretch through the central part of the ridges, dissected by a whole system of subparallel transform faults with a vertical displacement of up to 3-5 km. The horizontal displacement of individual parts of the rifts is several tens and the first hundreds of kilometers. The bottom of the rift valley is often lowered to a depth of 3000-4000 m, and the ridges bordering it are at depths of 1500-2000 m. The width of the valleys is 25-50 km. Mid-ocean ridges are characterized by high seismicity, high heat flow and active volcanism.

Such interesting formations as "black" and "white" smokers are confined to the area of ​​rift valleys of the mid-oceanic ridges. Here, where the oceanic crust is constantly renewed due to the outpouring of hot mantle basalts, high-temperature (up to 350 °) hydrothermal springs are widespread, the water of which is enriched with metals and gases. These sources are associated with the modern ore formation of sulfide ores on the ocean floor, which contain zinc, copper, lead and other valuable metals.

"Smokers" are gigantic, tens of meters high, truncated cones, from the tops of which jets of hot solutions and columns of black smoke are beating (Fig. 19.3). There are also inactive, long extinct hydrothermal structures. A.P. During the first geological expedition with deep-sea vehicles on the Mid-Atlantic Ridge, Lisitsyn managed to prove that these ancient buildings, which are accumulations of metals, the total mass of which is millions of tons, can survive under certain conditions. According to calculations, the share of these ore structures accounts for more than 99% of the total amount of sulfide ores, the origin of which is associated with the middle ridges.