East European Platform: landform. Minerals of the East European Platform
The East European (Russian) Plain is one of the largest plains in the world by area; It extends from the coast of the Baltic Sea to the Ural Mountains, from the Barents and White Seas to the Azov and Caspian Seas.
The East European Plain has the highest density of rural population, large cities and many small towns and urban-type settlements, and a variety of natural resources. The plain has long been developed by man.
Relief and geological structure
The East European Elevated Plain consists of hills with heights of 200-300 m above sea level and lowlands along which large rivers flow. The average height of the plain is 170 m, and the highest - 479 m - is on the Bugulminsko-Belebeevskaya Upland in the Ural part. The maximum elevation of the Timan Ridge is somewhat lower (471 m).
According to the characteristics of the orographic pattern within the Eastern European plain Three stripes are clearly visible: central, northern and southern. A strip of alternating large uplands and lowlands passes through the central part of the plain: the Central Russian, Volga, Bugulminsko-Belebeevskaya uplands and General Syrt are separated by the Oka-Don lowland and the Low Trans-Volga region, along which the Don and Volga rivers flow, carrying their waters to the south.
To the north of this strip, low plains predominate, on the surface of which smaller hills are scattered here and there in garlands and individually. From west to east-northeast, the Smolensk-Moscow, Valdai Uplands and Northern Uvals stretch here, replacing each other. They mainly serve as watersheds between the Arctic, Atlantic and internal (drainless Aral-Caspian) basins. From the Northern Uvals the territory descends to the White and Barents Seas. This part of the Russian Plain A.A. Borzov called it northern slope. Large rivers flow along it - Onega, Northern Dvina, Pechora with numerous high-water tributaries.
The southern part of the East European Plain is occupied by lowlands, of which only the Caspian is located on Russian territory.
The East European Plain has a typical platform topography, which is predetermined by the tectonic features of the platform: the heterogeneity of its structure (the presence of deep faults, ring structures, aulacogens, anteclises, syneclises and other smaller structures) with the unequal manifestation of recent tectonic movements.
Almost all large hills and lowlands of the plain are of tectonic origin, with a significant part inherited from the structure of the crystalline basement. In the process of a long and complex development path, they formed as a single territory in morphostructural, orographic and genetic terms.
At the base of the East European Plain lie the Russian plate with a Precambrian crystalline foundation and in the south the northern edge of the Scythian plate with a Paleozoic folded foundation. These include syneclises - areas of deep foundation (Moscow, Pechora, Caspian, Glazov), anteclises - areas of shallow foundation (Voronezh, Volgo-Ural), aulacogens - deep tectonic ditches, in the place of which syneclises subsequently arose (Kresttsovsky, So-ligalichsky, Moskovsky, etc.), protrusions of the Baikal foundation - Timan.
The Moscow syneclise is one of the oldest and most complex internal structures Russian plate with a deep crystalline foundation. It is based on the Central Russian and Moscow aulacogens, filled with thick strata of the Riphean and is expressed in relief by fairly large uplands - Valdai, Smolensk-Moscow and lowlands - Upper Volga, North Dvina.
The Pechora syneclise is located wedge-shaped in the northeast of the Russian Plate, between the Timan Ridge and the Urals. Its uneven block foundation is lowered to different depths- up to 5000-6000 m in the east. The syneclise is filled with a thick layer of Paleozoic rocks, overlain by Meso-Cenozoic sediments.
In the center of the Russian plate there are two large anteclises - the Voronezh and the Volga-Ural, separated by the Pachelma aulacogen.
The Caspian marginal syneclise is a vast area of deep (up to 18-20 km) subsidence of the crystalline basement and belongs to the structures of ancient origin; the syneclise is limited on almost all sides by flexures and faults and has angular outlines.
The southern part of the East European Plain is located on the Scythian epi-Hercynian plate, lying between the southern edge of the Russian plate and the alpine folded structures of the Caucasus.
Modern relief, which has undergone a long and complex history, turns out to be in most cases inherited and dependent on the nature of the ancient structure and manifestations of neotectonic movements.
Neotectonic movements on the East European Plain manifested themselves with different intensity and direction: in most of the territory they are expressed by weak and moderate uplifts, weak mobility, and the Caspian and Pechora lowlands experience weak subsidence (Fig. 6).
The development of the morphostructure of the northwestern plain is associated with the movements of the marginal part of the Baltic shield and the Moscow syneclise, therefore monoclinal (sloping) strata plains are developed here, expressed in orography in the form of hills (Valdai, Smolensk-Moscow, Belorussian, Northern Uvaly, etc.), and strata plains occupying a lower position (Verkhnevolzhskaya, Meshcherskaya). The central part of the Russian Plain was influenced by intense uplifts of the Voronezh and Volga-Ural anteclises, as well as subsidence of neighboring aulacogens and troughs. These processes contributed to the formation of layered, stepwise uplands (Central Russian and Volga) and the layered Oka-Don plain. The eastern part developed in connection with the movements of the Urals and the edge of the Russian plate, so a mosaic of morphostructures is observed here. In the north and south, accumulative lowlands of the marginal syneclises of the plate (Pechora and Caspian) are developed. Between them alternate stratified-tiered uplands (Bugulminsko-Belebeevskaya, Obshchiy Syrt), monoclinal-stratified uplands (Verkhnekamskaya) and the intraplatform folded Timan Ridge.
During the Quaternary, climate cooling in the northern hemisphere contributed to the spread of glaciation.
There are three glaciations on the East European Plain: Oka, Dnieper with the Moscow stage and Valdai. Glaciers and fluvioglacial waters created two types of plains - moraine and outwash.
The southern border of the maximum distribution of the Dnieper cover glaciation crossed the Central Russian Upland in the Tula region, then descended along the Don valley - to the mouth of the Khopr and Medveditsa, crossed the Volga Upland, then the Volga near the mouth of the Sura River, then went to the upper reaches of the Vyatka and Kama and crossed the Urals in area 60° N. Then came the Valdai glaciation. The edge of the Valdai ice sheet was located 60 km north of Minsk and went northeast, reaching Nyandoma.
Natural processes of the Neogene-Quaternary time and modern climatic conditions on the territory of the East European Plain determined various types of morphosculptures, which are zonal in their distribution: on the coast of the seas of the Arctic Ocean, marine and moraine plains with cryogenic relief forms are common. To the south lie moraine plains, transformed at various stages by erosion and periglacial processes. Along the southern periphery of the Moscow glaciation there is a strip of outwash plains, interrupted by remnant elevated plains covered with loess-like loams, dissected by ravines and ravines. To the south there is a strip of fluvial ancient and modern landforms on highlands and lowlands. On the coast of the Azov and Caspian Seas there are Neogene-Quaternary plains with erosional, depression-subsidence and aeolian relief.
The long geological history of the largest geostructure - the ancient platform - predetermined the accumulation of various minerals on the East European Plain. The richest deposits are concentrated in the foundation of the platform iron ores(Kursk magnetic anomaly). Associated with the sedimentary cover of the platform are deposits of coal (eastern part of Donbass, Moscow basin), oil and gas in Paleozoic and Mesozoic deposits (Ural-Volga basin), and oil shale (near Syzran). Building materials (songs, gravel, clays, limestones) are widely used. Brown iron ores (near Lipetsk), bauxites (near Tikhvin), phosphorites (in a number of areas) and salts (Caspian region) are also associated with the sedimentary cover.
Climate
The climate of the East European Plain is influenced by its position in temperate and high latitudes, as well as neighboring territories (Western Europe and Northern Asia) and the Atlantic and Arctic oceans. Total solar radiation per year in the north of the plain, in the Pechora basin, reaches 2700 mJ/m2 (65 kcal/cm2), and in the south, in the Caspian lowland, 4800-5050 mJ/m2 (115-120 kcal/cm2). The distribution of radiation across the plain changes dramatically with the seasons. In winter, radiation is much less than in summer, and more than 60% of it is reflected by snow cover. In January, the total solar radiation at the latitude Kaliningrad - Moscow - Perm is 50 mJ/m2 (about 1 kcal/cm2), and in the southeast of the Caspian lowland it is about 120 mJ/m2 (3 kcal/cm2). Radiation reaches its greatest value in summer and July; its total values in the north of the plain are about 550 mJ/m2 (13 kcal/cm2), and in the south - 700 mJ/m2 (17 kcal/cm2). All year round Western transport of air masses dominates over the East European Plain. Atlantic air brings coolness and precipitation in summer, and warmth and precipitation in winter. When moving east, it transforms: in summer it becomes warmer and drier in the ground layer, and in winter - colder, but also loses moisture
During the warm period of the year, from April, cyclonic activity occurs along the lines of the Arctic and polar fronts, shifting to the north. Cyclonic weather is most typical for the northwest of the plain, so cool sea air from temperate latitudes often flows into these areas from the Atlantic. It lowers the temperature, but at the same time it heats up from the underlying surface and is additionally saturated with moisture due to evaporation from the moistened surface.
The position of January isotherms in the northern half of the East European Plain is submeridional, which is associated with greater frequency of occurrence in the western regions of the Atlantic air and its lesser transformation. The average January temperature in the Kaliningrad region is -4°C, in the western part of the compact territory of Russia about -10°C, and in the northeast -20°C. In the southern part of the country, isotherms deviate to the southeast, amounting to -5...-6°C in the area of the lower reaches of the Don and Volga.
In summer, almost everywhere on the plain, the most important factor in the distribution of temperature is solar radiation, so isotherms, unlike in winter, are located mainly in accordance with geographic latitude. In the far north of the plain, the average July temperature rises to 8°C, which is associated with the transformation of air coming from the Arctic. The average July isotherm of 20°C goes through Voronezh to Cheboksary, approximately coinciding with the border between forest and forest-steppe, and the Caspian lowland is crossed by an isotherm of 24°C.
The distribution of precipitation over the territory of the East European Plain depends primarily on circulation factors (westerly transport of air masses, the position of the Arctic and polar fronts and cyclonic activity). Especially many cyclones move from west to east between 55-60° N. latitude. (Valdai and Smolensk-Moscow uplands). This strip is the most humidified part of the Russian Plain: the annual precipitation here reaches 700-800 mm in the west and 600-700 mm in the east.
Relief has an important influence on the increase in annual precipitation: on the western slopes of the hills, 150-200 mm more precipitation falls than on the underlying lowlands. In the southern part of the plain, maximum precipitation occurs in June, and in the middle zone - in July.
The degree of moisture in an area is determined by the ratio of heat and moisture. It is expressed in various quantities: a) the moisture coefficient, which on the East European Plain varies from 0.35 in the Caspian Lowland to 1.33 or more in the Pechora Lowland; b) the dryness index, which varies from 3 in the deserts of the Caspian lowland to 0.45 in the tundra of the Pechora lowland; c) average annual difference in precipitation and evaporation (mm). In the northern part of the plain, moisture is excessive, since precipitation exceeds evaporation by 200 mm or more. In the band of transitional moisture from the upper reaches of the Dniester, Don and Kama rivers, the amount of precipitation is approximately equal to evaporation, and the further south of this band, the more evaporation exceeds precipitation (from 100 to 700 mm), i.e., moisture becomes insufficient.
Differences in the climate of the East European Plain affect the nature of vegetation and the presence of fairly clearly defined soil and plant zonation.
In areas where rocks of the crystalline foundation of platforms come to the surface, for example in Ukraine - in the middle reaches of the Dnieper near the city of Dnepropetrovsk and Krivoy Rog, it is clear that these rocks are folded, broken by cracks and have the same structures as in the mountains. From this it was concluded that once upon a time, in the first stages of the formation of platforms, mountains existed in the place of modern plains. Then came long periods of quiet tectonic life, during which the mountains were almost completely destroyed by external forces of denudation. Mountain ranges and peaks were lowered and leveled. An almost plain was formed, which the American geologist and geographer William Davis, one of the founders of the science of geomorphology, proposed to call peneplain (“pene” - almost, “plain” - plain). The primary ancient peneplains gradually sank and were covered by the waters of the Paleozoic and Mesozoic seas. Sediment layers accumulated at the bottom of the seas. After the departure of the sea and the gentle general uplift of the platform, these sedimentary rocks formed a platform cover.
Simultaneously with the general weak tectonic uplifts and subsidences of the entire platform, its individual sections experienced local (local) movements up or down. It was these movements that formed the gentle uplifts and deflections in the surface of the foundation and in modern relief- those hills and flat depressions that we have already talked about.
Local movements on the platforms continue today. Accurate measurements showed that, for example, the Kursk region rises by 3.6 mm per year, and Krivoy Rog by 10 mm per year. The seeming inviolability and immobility of the surface of our planet is illusory. In fact, movements of different directions and different strengths, caused by not yet fully understood processes occurring in the bowels of the Earth, occur continuously throughout the entire history of the planet.
On the plains. where natural grassy vegetation is destroyed, under the influence of heavy rains or during rapid snow melting, jets of water collecting on the slopes erode them and form deep, rapidly growing ravines.
The surface exposed from under the waters of the departed sea is affected by exogenous forces - river erosion and accumulation, wind, gravitational shedding, collapse and sliding of collapsing rocks, their dissolution groundwater. As a result of the interaction of tectonic movements and exogenous processes, the hilly or flat, undulating or basin relief of the plains was formed. And the stronger the tectonic movements, the more strongly they are affected by exogenous processes. However, these processes depend not only on tectonic movements. Different parts of the earth's surface receive different amounts of solar heat. Some areas receive a lot of precipitation in the form of rain and snow, while others suffer from drought. Differences in climate also determine differences in the operation of exogenous processes.
In humid countries, the main work is done by water. After rains or snow melting, it is partially absorbed into the soil covered with forests and meadows, and partially flows down the slopes. Both soil and surface water collects in streams, which connect into small rivers, and then into large water streams. Rivers flow, eroding their beds, washing away the banks, causing them to collapse and slide. A network of large and small river valleys emerges. Valley relief is a distinctive feature of geomorphological landscapes in humid areas.
Where ravines are located close to each other, an impassable mixture of sharp and narrow ridges and “small gorges” is formed. This type of terrain is called badland or bad lands.
In forest-steppe and steppe areas there is less precipitation, and it falls very unevenly throughout the year. Rivers and valleys here no longer dissect the surface so densely. But where the natural grassy vegetation is destroyed, during rare but heavy rainfalls or during the spring rapid melting of snow, streams of water collecting on the slopes cut them and form deep, rapidly growing ravines.
In arid areas of semi-deserts and deserts, rain falls very rarely. The vegetation here is sparse and does not cover the soil with a protective carpet. The main acting force is the wind. It reigns everywhere in deserts, even in rare riverbeds, dry most of the year.
The wind blows dust and grains of sand out of the soil. Black storms carry dust for many hundreds of kilometers. Falling to the ground when the wind subsides, this dust can form powerful layers of dusty deposits - the so-called loess.
Sand, carried by the wind in the air or rolled over a bare surface, accumulates in deserts, piling up moving dunes, dune chains and ridges. The pattern of the aeolian relief of sands, especially clearly visible on aerial photographs, is determined by the regime and strength of the winds and the obstacles encountered along their path - mountain ranges and ridges.
The climate of any region of the Earth did not remain the same. The causes of climate change on our planet are complex and not yet fully understood. Scientists associate these changes with cosmic phenomena, with changes in the position of the Earth's axis and migrations of the poles, with vertical and horizontal displacements of continents.
Lake Elk. Karelia. Such lakes are located in depressions of the moraine-glacial relief.
The Earth has experienced strong climate fluctuations in recent geological times, especially during the Quaternary period (Anthropocene). During this period, large glaciations arose in the polar regions of the globe. In Eurasia, glaciers gradually descended from the mountains of northern Scandinavia, the Urals, Central Siberia. They connected with each other and formed vast ice sheets. In Europe, during the maximum glaciation (200-300 thousand years ago), the edge of the ice sheet, several hundred meters high, reached the northern foothills of the Alps and Carpathians, descended in tongues along the valleys of the Dnieper to Dnepropetrovsk and the Don to Kalach.
The ice in the ice sheet slowly spread from the center to the edges. On the elevations of the subglacial relief, glaciers tore off and smoothed rocks, turning out large boulders and blocks of rock. And now, especially in areas close to the centers of previous glaciations - in Scandinavia, on the Kola Peninsula, in Karelia, smoothed and scratched, and sometimes polished to a shine, granite rocks, the so-called sheep's foreheads, are perfectly preserved. By the location of scratches and marks on these rocks and glacial boulders, scientists determine the direction of movement of ancient, long-vanished glaciers.
Spotted tundra. It is flat, dry, clayey tundra with clay patches the size of a plate or wheel, usually completely devoid of vegetation. The patches are interspersed with dry, vegetated tundra or bordered by a border of plants.
Stones were frozen into the ice, and it carried them hundreds and thousands of kilometers, piling them up along the edges of the ice sheets in the form of ridges and hilly moraines. Streams of unfrozen water flowed in the cracks on the glaciers, inside and under them, saturated with sand, pebbles and gravel. Some cracks were completely clogged with sediment. And when the glaciers began to melt and retreat, sand and gravel masses were projected from cracks onto the surface freed from under the ice. Winding ridges formed. Such sand ridges up to 30-40 km long and from several meters to 2-3 km wide are often found in the Baltic states, near Leningrad, Karelia, and Finland. They are called azami (ridge in Swedish). Eskers, moraine ridges and hills, as well as kamas - rounded sandy mounds and drumlins - hills of a characteristic elongated shape - are typical witnesses to the relief-forming work of ancient cover glaciations that covered vast territories.
Residual glacial moraine, composed of loose loams with an accumulation of rock fragments.
Glaciers advanced and retreated several times in the northern regions of Europe, Asia, and North America. During these great Quaternary glaciations, air temperatures throughout the Earth decreased, especially strongly in the polar and temperate latitudes. In the vast areas of Europe, Siberia and North America, where glaciers did not penetrate, the soil froze to a depth of several hundred meters. Permafrost of soils was formed, which has survived to this day in Western and Eastern Siberia, on Far East, in Canada, etc. In summer, the surface of the frozen ground thaws, the soil overflows with water, and many small lakes and swamps form. In winter, all this water freezes again. When freezing, as you know, water expands. Ice contained in soils breaks them apart with cracks. The network of these cracks often has a regular lattice (polygonal) pattern. The surface bulges and lumps form. Trees in such areas lean in different directions. When thawing soil ice and permafrost, basins and depressions are formed - thermokarst relief. Permafrost heaving and thawing subsidence destroy buildings, roads, airfields, and people developing polar frozen regions have to devote a lot of effort to combat these harmful natural phenomena.
Relief of the East European PlainAlmost the entire length is dominated by gently sloping terrain. The East European Plain almost completely coincides with the East European Platform. This circumstance explains its flat terrain, as well as the absence or insignificance of manifestations of such natural phenomena, like earthquakes, volcanism. Large hills and lowlands arose as a result of tectonic movements, including along faults. The height of some hills and plateaus reaches 600-1000 meters.
On the territory of the Russian Plain, platform deposits lie almost horizontally, but their thickness in some places exceeds 20 km. Where the folded foundation protrudes to the surface, hills and ridges are formed (for example, the Donetsk and Timan ridges). On average, the height of the Russian Plain is about 170 meters above sea level. The lowest areas are on the Caspian coast (its level is approximately 26 meters below the level of the World Ocean).
Relief of the West Siberian PlainThe differentiated subsidence of the West Siberian Plate in the Mesozoic and Cenozoic led to the predominance within its boundaries of processes of accumulation of loose sediments, the thick cover of which levels out the surface irregularities of the Hercynian basement. Therefore, the modern West Siberian Plain has a generally flat surface. However, it cannot be considered as a monotonous lowland, as was recently believed. Overall territory Western Siberia has a concave shape. Its lowest areas (50-100 m) are located mainly in the central (Kondinskaya and Sredneobskaya lowlands) and northern (Lower Obskaya, Nadymskaya and Purskaya lowlands) parts of the country. Along the western, southern and eastern outskirts stretch low (up to 200-250 m) hills: North Sosvinskaya, Turinskaya, Ishimskaya, Priobskoye and Chulym-Yenisei plateaus, Ketsko-Tymskaya, Verkhnetazovskaya, Nizhneeniseiskaya. A clearly defined strip of hills is formed in the inner part of the plain by the Siberian Uvals (average height - 140-150 m), stretching from the west from the Ob to the east to the Yenisei, and the Vasyugan Plain parallel to them.
Some orographic elements of the West Siberian Plain correspond to geological structures: gentle anticlinal uplifts correspond, for example, to the Verkhnetazovskaya and Lyulimvor hills, and the Barabinskaya and Kondinskaya lowlands are confined to syneclises of the base of the plate. However, in Western Siberia, discordant (inversion) morphostructures are also common. These include, for example, the Vasyugan Plain, which formed on the site of a gently sloping syneclise, and the Chulym-Yenisei Plateau, located in the zone of basement deflection.
The West Siberian Plain is usually divided into four large geomorphological regions: 1) marine accumulative plains in the north; 2) glacial and water-glacial plains; 3) periglacial, mainly lacustrine-alluvial plains; 4) southern non-glacial plains (Voskresensky, 1962).
The differences in the relief of these areas are explained by the history of their formation in Quaternary times, the nature and intensity of recent tectonic movements, and zonal differences in modern exogenous processes. In the tundra zone, relief forms are especially widely represented, the formation of which is associated with the harsh climate and widespread permafrost. Thermokarst depressions, bulgunnyakhs, spotted and polygonal tundras are very common, and solifluction processes are developed. Typical of the southern steppe provinces are numerous closed basins of suffusion origin, occupied by salt marshes and lakes; The network of river valleys here is sparse, and erosional landforms in the interfluves are rare.
The main elements of the relief of the West Siberian Plain are wide, flat interfluves and river valleys. Due to the fact that the interfluve spaces account for most of the country's area, they determine the general appearance of the plain's topography. In many places, the slopes of their surfaces are insignificant, the flow of precipitation, especially in the forest-swamp zone, is very difficult and the interfluves are heavily swamped. Large areas are occupied by swamps north of the Siberian Railway line, on the interfluves of the Ob and Irtysh, in the Vasyugan region and the Barabinsk forest-steppe. However, in some places the relief of the interfluves takes on the character of a wavy or hilly plain. Such areas are especially typical of some northern provinces of the plain, which were subject to Quaternary glaciations, which left here piles of stadial and bottom moraines. In the south - in Baraba, on the Ishim and Kulunda plains - the surface is often complicated by numerous low ridges stretching from northeast to southwest.
Another important element The country's topography is river valleys. All of them were formed under conditions of slight surface slopes and slow and calm river flows. Due to differences in the intensity and nature of erosion, the appearance of the river valleys of Western Siberia is very diverse. There are also well-developed deep ones (up to 50-80 m) valleys of large rivers - the Ob, Irtysh and Yenisei - with a steep right bank and a system of low terraces on the left bank. In some places their width is several tens of kilometers, and the Ob valley in the lower reaches reaches even 100-120 km. The valleys of most small rivers are often just deep ditches with poorly defined slopes; During spring floods, water completely fills them and even floods neighboring valley areas.
The East European Platform is located on the Russian or East European Plain, the foundation of which extends to the northern borders. In the east, the platform reaches the western slope of the Ural Mountains, and in the south and southwest it is limited by the mountains of the Caucasus, Crimea, and the Carpathian Mountains of the Alpine orogeny. The main geostructures of the platform are syneclises– areas of deep foundation, anteclises– areas of shallow foundation, aulacogens– deep tectonic ditches.
Separate parts of the platform sank in the Lower Paleozoic, as a result of which the Baltic and Ukrainian shields, the Voronezh ledge and the Oka-Volga anteclise became isolated. The Baltic and Moscow syneclises separated the platform uplifts. Also large elements of the platform are the Saratov-Ryazan syneclise and the Kama-Pechora syneclise. The East European Platform has a Precambrian crystalline basement, and in the south, the northern edge of the Scythian plate has a Paleozoic folded basement. On the Precambrian foundation of the platform there are strata of Precambrian and Phanerozoic sedimentary rocks with slightly disturbed occurrence.
One of the oldest and most complex internal structures of the East European Platform is Moscow syneclise, Central Russian and Moscow aulacogens, which are filled with Riphean strata. During the Quaternary period, uneven uplifts occurred here, which in the relief were indicated by large hills.
Pechora syneclise passes in the northeast of the platform between the Timan Ridge and the Urals. Its block foundation in the east descends to a depth of $5$-$6$ thousand m. The syneclise is filled with thick strata of Paleozoic rocks, overlain by Meso-Cenozoic deposits.
In the center of the platform there are large anteclises - Voronezh and Volga-Ural. They are separated by the Pachelma aulacogen. To the north, the Voronezh anteclise gently descends into the Moscow syneclise. Sediments low power, represented by Ordovician, Devonian and Carboniferous rocks, cover its foundation, and on the steep southern slope there are Carboniferous, Cretaceous and Paleogene rocks. Large uplifts and depressions (arches and aulacogens) form the Volga-Ural anteclise. The sedimentary cover of the arches has a thickness of at least $800$ m.
Caspian regional syneclise. The crystalline foundation of this vast area has a deep dive reaching $20$ km. The syneclise is an ancient structure and is bounded on all sides by flexures and faults. Its outlines are angular. The Ergeninsky and Volgograd flexures frame it from the west, and in the north - the flexures of General Syrt. Further subsidence to $500$ m occurred in the Neogene-Quaternary time, accompanied by the accumulation of a thick layer of marine and continental sediments.
On south part of the East European Plain lies on the Scythian Epihercynian Plate.
Relief of the East European Plain
The Russian Plain, located on the East European Platform, is formed by hills whose height above sea level is $200$-$300$ m. Its average height is $170$ m, and its maximum is $479$ m, located in the Ural part on the Bugulma-Belebeevskaya Upland. If we talk about the features of the orographic pattern, then within the plain we can distinguish central, northern, southern parts.
central part is represented by a strip of alternating large uplands and lowlands - the Central Russian, Volga, Bugulminsko-Belebeevskaya uplands and the General Syrt. They are separated by the Oka-Don lowland and the Low Volga region. Here the Volga and Don flow in a southern direction.
IN northern part The relief consists of low plains with scattered small hills. Replacing each other, the Smolensk-Moscow, Valdai Uplands and Northern Uvaly stretch in the north-east direction. These are peculiar watersheds between two oceans and an internal closed basin. Toward the White and Barents Seas from the Northern Uvals, the territory of the plain decreases, as evidenced by the Onega, Northern Dvina, and Pechora rivers flowing to the north.
South part The plains are occupied by lowlands, but within Russian territory only the Caspian Lowland can be called.
Note 1
The relief of the East European Plain is typical platform, predetermined by its tectonic features, i.e. heterogeneity of the structure, as evidenced by the presence of deep faults, ring structures, aulacogens, anteclises, syneclises and the unequal manifestation of recent tectonic movements.
The large hills and lowlands of the East European Plain are of tectonic origin. They were formed as unified territories in morphostructural, orographic and genetic terms. The formation of the relief of the plain was significantly influenced by glaciers - Okskoye, Dnieper, Valdai. Glaciers participated in the creation of moraine and outwash plains. The moraine relief, eroded by the waters of the Dnieper glacier, has not survived to our time
Minerals of the East European Plain
The geological history of the ancient platform influenced the formation of minerals.
Open on the plain largest deposit iron ores– Kursk Magnetic Anomaly (KMA). The deposit's reserves are estimated at $31.9 billion tons, which is $57.3% of the country's total ore reserves. The ore occurs mainly in the Kursk and Belgorod regions. KMA ores contain $41.5% iron, which is higher than the average for Russia. Ore is mined at the Mikhailovskoye, Lebedinskoye, Stoilenskoye, and Gubkinskoye deposits. Small ore reserves are noted in Tula and Oryol regions. Close location to the surface of the earth allows for mining open method, which has a huge impact on the nature of the chernozem zone of the Russian Plain, namely, it leads to the destruction of tens of thousands of hectares of chernozem soil.
Reserves have been explored within the Belgorod region bauxite– Vislovskoye field. Alumina content is estimated at $20$-$70$%.
Chemical raw materials on the Russian Plain it is represented by phosphorites in the Moscow region, potassium, rock salts of the Verkhnekamsk basin and the Iletsk deposit in the Orenburg region. The salts of lakes Elton and Baskunchak are also known.
Reserves construction raw materials, represented by chalk, marl, cement, fine-grained sand, are common in the Belgorod, Bryansk, Moscow, and Tula regions. High-quality cement marls are known in the Saratov region. Glass sands in the Ulyanovsk region, in the Orenburg region there is an asbestos deposit. Quartz sands Bryansk and Vladimir regions are used for the production of artificial quartz, glass, and crystal tableware. Kaolin clays from the Tver and Moscow regions are used to operate the porcelain and faience industry.
There are deposits on the territory of the East European Plain hard and brown coals. They are extracted in the Pechora, Donetsk, and Moscow basins. Brown coals of the Moscow region are used as chemical raw materials and as technological fuel for the ferrous metallurgy of the region.
Within the Volga-Ural and Timan-Pechora oil and gas regions they produce oil and natural gas . There are also gas condensate fields in the Astrakhan and Orenburg regions.
Oil shale known in the Leningrad, Pskov regions, in the Middle Volga region and in the north of the Caspian lowland.
Significant reserves peat, which is of significant importance in the fuel balance of some regions of the plain. Within the Central Federal District alone, its reserves amount to $5 billion tons. There are peat deposits in the Kirov and Nizhny Novgorod regions and in the Republic of Mari El.
Deposits discovered in the Arkhangelsk region diamonds.
Note 2
Compared to other physical-geographical countries of Russia, the East European Plain has been inhabited for a long time and has high density population, the greatest development, which means that it has undergone significant anthropogenic changes.
For centuries, the Russian Plain served as a territory connecting Western and Western trade routes. eastern civilization. Historically, two busy trade arteries ran through these lands. The first is known as the “path from the Varangians to the Greeks.” According to it, as is known from school history, medieval trade in goods of the peoples of the East and Rus' with the states of Western Europe was carried out.
The second is the route along the Volga, which made it possible to transport goods by ship to Southern Europe from China, India and Central Asia and in the opposite direction. The first Russian cities were built along trade routes - Kyiv, Smolensk, Rostov. Veliky Novgorod became north gate routes from the “Varangians”, who protected the safety of trade.
Now the Russian Plain is still a territory of strategic importance. The capital of the country and the largest cities are located on its lands. The most important administrative centers for the life of the state are concentrated here.
Geographical position of the plain
The East European Plain, or Russian, occupies territories in eastern Europe. In Russia, these are its extreme western lands. In the northwest and west it is limited by the Scandinavian Mountains, the Barents and White Seas, the Baltic coast and the Vistula River. In the east and southeast it neighbors Ural mountains and the Caucasus. In the south, the plain is limited by the shores of the Black, Azov and Caspian seas.
Relief features and landscape
The East European Plain is represented by a gently sloping relief, formed as a result of faults in tectonic rocks. Based on relief features, the massif can be divided into three stripes: central, southern and northern. The center of the plain consists of alternating vast hills and lowlands. The north and south are mostly represented by lowlands with rare low altitudes.
Although the relief is formed in a tectonic manner and minor tremors are possible in the area, there are no noticeable earthquakes here.
Natural areas and regions
(The plain has planes with characteristic smooth drops)
The East European Plain includes all natural areas, found in Russia:
- Tundra and forest-tundra are represented by the nature of the north of the Kola Peninsula and occupy a small part of the territory, slightly expanding to the east. The vegetation of the tundra, namely shrubs, mosses and lichens, is replaced by birch forests of the forest-tundra.
- Taiga, with its pine and spruce forests, occupies the north and center of the plain. On the borders with mixed broad-leaved forests, areas are often swampy. A typical Eastern European landscape - coniferous and mixed forests and swamps give way to small rivers and lakes.
- In the forest-steppe zone you can see alternating hills and lowlands. Oak and ash forests are typical for this zone. You can often find birch and aspen forests.
- The steppe is represented by valleys, where oak forests and groves, forests of alder and elm grow near the river banks, and tulips and sages bloom in the fields.
- In the Caspian lowland there are semi-deserts and deserts, where the climate is harsh and the soil is saline, but even there you can find vegetation in the form of various varieties of cacti, wormwood and plants that adapt well to sudden changes in daily temperatures.
Rivers and lakes of the plain
(River on a flat area of the Ryazan region)
The rivers of the “Russian Valley” are majestic and slowly flow their waters in one of two directions - north or south, to the Arctic and Atlantic oceans, or to the southern inland seas of the continent. Northern rivers flow into the Barents, White or Baltic seas. Rivers of the southern direction - to the Black, Azov or Caspian Sea. The largest river in Europe, the Volga, also “flows lazily” through the lands of the East European Plain.
The Russian plain is a kingdom natural water in all its manifestations. A glacier that passed through the plain thousands of years ago formed many lakes on its territory. There are especially many of them in Karelia. The consequences of the presence of the glacier were the emergence in the North-West of such large lakes as Ladoga, Onega, and the Pskov-Peipus reservoir.
Under the thickness of the earth in the localization of the Russian Plain, reserves of artesian water are stored in the amount of three underground basins of huge volumes and many located at shallower depths.
Climate of the East European Plain
(Flat terrain with slight drops near Pskov)
The Atlantic dictates the weather regime on the Russian Plain. Western winds, air masses, moving moisture, make summers on the plain warm and humid, winters cold and windy. During the cold season, winds from the Atlantic bring about ten cyclones, contributing to variable heat and cold. But air masses from the Arctic Ocean also tend to the plain.
Therefore, the climate becomes continental only in the interior of the massif, closer to the south and southeast. The East European Plain has two climatic zones - subarctic and temperate, increasing continentality to the east.
This physical-geographical country with an area of about 4 million square meters. km. – the largest within Russia. The geographical literature has established the idea of the coincidence of the boundaries of the Russian Plain and the East European Platform. The boundaries of the latter run in the west along the line: the south of the Scandinavian Peninsula - the mouth of the Danube - the Perekop Isthmus - the lower reaches of the Seversky Donets - the Volga delta - Mugodzhary; in the east - along the western foot of the Urals. Administrative boundaries divide the territory of the Russian Plain into foreign and Russian parts. We have to study part of the East European Plain within the borders of the former USSR.
Helogical development. This part of the Russian Plain is based on two geostructures of the second rank: the Russian Plate and the Ukrainian Shield. Like the Baltic shield, they survived the nuclear, protoplatform and platform-geosynclinal epochs of development (see the corresponding section). In the Phanerozoic, the development of the Russian plate was very different from the genesis of shields. Her foundation complex orthogonal and diagonal fault systems was divided into many blocks that experienced differentiated subsidence. Already in the Precambrian, a large number of narrow linearly elongated rift-like structures, called aulacogens by N.S. Shatsky, were formed along the faults. In the Riphean, volcanogenic and sedimentary strata began to accumulate on their bottoms. In the Phanerozoic, sedimentation covered the entire area of the geostructure, regardless of the relief of the foundation—the formation of a cover and the transformation of the geostructure into a two-story (slab) structure took place. The processes of transformation of the foundation also continued actively.
The development of aulacogens followed two paths: conservation or degeneration into syneclises or exagonal depressions (see the corresponding section general overview). The surface of the basement was flooded by shallow epiplatform seas, at the bottom of which sedimentation successively occurred. Transgressions of the seas have never covered the entire surface of the Russian plate at the same time. In the early Paleozoic (Cambrian, Ordovician, Silurian) they timidly penetrated into the extreme north-west of the plate, forming sandy-clayey layers (not cemented!) of Glint. The Devonian seas covered significantly large areas northwest (main Devonian field). Marine and lagoonal facies Carboniferous period cover the Moscow region from the north-west and south like a horseshoe. Lagoonal sediments of the Permian period filled the northeast of the Russian plate and the structures of the Cis-Ural foredeep (the main Permian field). Thus, the Paleozoic transgressions covered the northern strip of the Russian plate, successively passing along it from west to east.
In the Mesozoic, the maximum transgressions shifted to the middle zone of the plate. Triassic lagoonal facies superimposed on Permian deposits, moving especially strongly into the middle zone in the pre-Ural part of the structure. Jurassic deposition reflected further reduction of lagoons in the middle zone. During the Cretaceous period, marine and lagoonal deposits spread over vast areas, especially in the western middle zone. In the Cenozoic, the maximum transgressions covered the south of the Russian plate, successively moving from west to east.
Geotectonic structure . Lower structural floor Russian plate and Ukrainian shield similar to the foundation of the Baltic Shield (see the corresponding section). The plate includes geostructures of the third rank: syneclises (Moscow, Baltic, Black Sea), exagonal depressions (Caspian, Pechora), anteclises (Volga-Ural, Voronezh, Belorussian and similar slopes of neighboring shields - the Baltic and Ukrainian). The thickness of the cover within the anteclises is small (the minimum within the Voronezh anteclise is 40 m), in syneclises it reaches 2–3 km, in exagonal depressions – 9–25 km. ABOUT fundamental differences syneclises and exagonal depressions, see the corresponding section of the general overview. On a surface Ukrainian shield There is a thin cover of Paleogene and Neogene deposits, so the basement rocks are exposed only in the valleys of large rivers. Structures Timan uplift similar to shields, but they developed in folded complexes of the Riphean and underwent folding in the Baikal era. The East European Platform forms a significant part of the Eurasian lithospheric plate, which experienced virtually no significant horizontal movements.
Relief. Orography and hypsometry . The ancient relief of the Russian Plain has not been preserved due to its rapid variability. The modern relief was formed under the influence of the latest tectonics. Very weak, weak, and less often moderate uplifts predominated. In the Caspian, Pechora, and Black Sea lowlands, weak subsidence was observed. This differentiation of the latest movements, with their overall low intensity, determined the universal distribution of plains of different altitudinal levels. In the northern strip of the Russian Plain, lowlands predominate: Pechora and Dvinsko-Mezen (against the general lowland background of which small hills up to 275 - 300 m high are scattered). They are separated by the uplands of Timan and Kanin Kamen, 200–300 m high. In the extreme west there is the complexly dissected Baltic Plain, against the low-lying background of which the low (maximum 145–300 m) uplands stand out: Kurzeme, Vidzeme, Zhamait.
In the middle zone, highlands and lowlands alternate. Along the Northern Uvals, Valdai, Smolensk-Moscow, Belorussian and smaller uplands, the Klinsko-Dmitrovskaya ridge, there is a watershed of rivers of the northern and southern directions. Lowland woodlands alternate with them - Vyatsko-Kama, Unzhensko-Vetluzhskoye, Meshcherskoye, Pripyatsko-Dnieper. To the south, meridionally oriented elevations alternate: High Trans-Volga region (General Syrt and Bugulminsko-Belebeevskaya); Privolzhskaya and Ergeni; Central Russian and Donetsk Ridge; Volyn, Dnieper, Podolsk, Kodri and lowlands: Low Trans-Volga region, Oksko-Don, Dnieper. At one time, such alternation led to the emergence of the doctrine of the undulating nature of the relief.
In the south of the Russian Plain, dominance again passes to the low-lying plains (Caspian, Kumo-Manych depression, Black Sea and North Crimean). The highest altitudes, close to 500 m, are reached in areas adjacent to the Carpathians; the minimum altitude is observed on the shores of the Caspian Sea and is 26 m below sea level. The average altitude of the Russian Plain is estimated at 170 m.
Morphostructure. The morphostructure of the strata plains clearly predominates on the horizontally and subhorizontally lying layers of the cover of the Russian plate. In the peripheral areas of the East European Plain, flat (no more than 3–5 degrees) monoclinal bedding of layers predominates; alternation of weak and armoring layers is often observed. This leads to the formation of monoclinal-layered plains with a wide distribution of asymmetrical ridges - cuestas. The classic ones are the cuestas of the northwestern part of the Russian Plain. Along the southern coast of the Gulf of Finland and Lake Ladoga, cuestas called Glint (or Baltic-Ladoga ledge) were formed on strata of Cambrian, Ordovician and Silurian age. Cuestas are also developed within the main Devonian field and in the Carboniferous zone.
IN central regions The Russian Plain is dominated by the horizontal occurrence of layers in which formation-denudation hills were formed (Central Russian, Volga and others). When alternating weak and armoring layers, multi-tiered-stratal plains with stepped relief are formed. Within the lowland plains arose accumulative plains, the largest of which are the Caspian, Black Sea, Pechora, Oksko-Don. On the Dnieper Upland, where crystalline rocks of the basement of the Ukrainian shield lie under a thin cover, the morphostructure of a semi-buried basement plain has formed. Within the Timan and Donetsk ridges, structural-denudation ridge uplands similar to the basement plains were formed.
The influence of anthropogene events on the relief. Pleistocene glaciation . Along with the Alps and North America The Russian Plain was a kind of testing ground for the study of the Pleistocene. A number of study methods have been proposed, among which stratigraphic and paleontological ones are of particular importance. The stratigraphic method involves a detailed study and comparison of geological sections of the Pleistocene and, above all, moraines, fluvioglacial deposits, and in the periglacial region - loess and loam. Among paleontological remains, plant remains play an important role, which are usually divided into two complexes. Complex dryad flora is typical for glacial ones. For it, the remains of polar willow and birch, partridge grass or dryad grass, club mosses, diatoms and other frost-resistant representatives are common. Typical for interglacials Brazenieva flora (water lily, yew, hornbeam, fossil hazel, linden, holly, forest grape).
Okskoe glaciation covered large areas, its southern border was located only slightly north of the border of maximum glaciation. The glacier moved a particularly large amount of loose, often sandy, material and leveled the surface. Maximum Dnieper the glacier in the southern regions of the Russian Plain had a thickness of no more than 500 - 700 m (in the center – 4900 m), since it could not cover the Central Russian Upland. Its distant penetration to the south was facilitated by the previous leveling of the surface made by the Oka glacier, the relatively “high” temperature of the ice and, as a result, the plasticity and strong watering of the ice. The huge mass of the glacier “pushed through” earth's crust approximately 1 km, and when the ice moved, it created glacial dislocations. At the southern border, the pressure of the glacier has weakened greatly, the terminal moraines are thin, but the scale of water-glacial deposits is significant. During Moscow During the glaciation, the glacier, under the influence of the Valdai Hills, was divided into two large tongues, one of which moved to the south, the other to the southeast. The Valdai glacier developed in conditions of a particularly harsh climate, so the ice was hard and low-plasticity, glacier advancement was minimal, but gouging was exacerbated, moraine deposits were enriched with boulders, and moraine relief forms were most clearly expressed.
In the periglacial zone, permafrost became widespread in the Pleistocene. During the era of maximum glaciation, its southern border reached the lower reaches of the Volga, Don and Dnieper. In the Holocene, it quickly degraded within 1–1.5 thousand years. Relict forms of cryogenic relief have been preserved - traces of fissure-polygonal formations, “wedges” of ice wedges, thermokarst depressions and others. Aeolian forms were widespread, relics of which are present in the modern relief: on the outwash plains of woodlands there are sandy formations (dunes, ridges), from the latitude of Moscow to the coasts of the southern seas there is a smoothed relief in loess deposits. In the latter, in the Pleistocene, a valley-gully relief was already formed.
Evolution of the Black Sea–Caspian Basin . Under the influence of rhythmic climate changes and tectonic movements, the following transgressions appeared in the south of the Russian Plain (see Table 2).
Table 2. Transgressions of the Black Sea-Caspian basin in the Pleistocene.
