BLACK LANDS OF THE CASPIAN DEPRESSION
Black Lands (Kalmyk "har gazr") is a semi-desert territory, deprived of continuous snow cover in winter due to strong winds. Black sagebrush and brown semi-desert soils reinforce the “color” meaning of the placename, but the word “black” implies more than just color.

In aerial photography, the Caspian depression (depression) looks like a crown crowning the northern coast of the Caspian Sea. This territory is a flat plain, the southern part of which lies almost 30 m below the level of the World Ocean, and in the northern part the height rises to 150 m above ocean level (Indera, Big and Small Bogdo mountains). The Caspian lowland is located within the boundaries of the Caspian syneclise (from ancient Greek “together” and “inclination”) - a gentle depression of the earth’s crust formed in the Paleozoic. The folded basement of the syneclise lies at a depth of 3000-4000 m and is covered with a thickness of sediments, the thickness of which reaches the greatest depth here for the Russian Platform. In ancient times, the Caspian Lowland was part of the World Ocean; the modern relief was influenced by numerous ups and downs of the Caspian Sea.

In the south of the northwestern sector of the Caspian lowland, between the Kuma-Manych depression,

The Ergeninskaya Upland and the Volga (at the junction with the Sarpinskaya Lowland) are the so-called Black Lands. This waterless territory with uncomfortable climatic conditions and natural foci of plague, leprosy (the old name is leprosy) and other diseases are unsuitable for life. The population density here is extremely low - less than 4 people/km2. IN summer time Dust storms rage here, up to 40 days a year. The only direction of agriculture in these places is transhumance. Having deprived the Black Lands of water, nature did not skimp on minerals: over hundreds of millions of years, sedimentary rocks accumulated here, and now the Black Lands are the region of the richest Caspian oil field, a place of extraction of uranium, titanium, precious metals - gold, silver and platinum, rare earth elements - scandium, yttrium, rhenium, gallium.

Active mining also has a negative effect: the surface of the Black Lands is quickly turning into an anthropogenic desert (especially considering that the soil here began to form only 4-5 thousand years ago, there is almost no turf). To preserve the local ecosystem, a state government was created biosphere reserve"Black Lands".

In the northeast, “Khar Gazr” descends into the Volga delta, to the Caspian Sea, where stripes of Baer’s mounds (first described in 1866 by academician K. M. Baer) stretch along the coast - sand ridges of regular shape with a height of 6 to 45 m, width 200-300 m and up to several kilometers long, alternating with ilmens (small lakes overgrown with reeds). Human economic activity can lead to their complete destruction in the near future.

The Volga-Akhtuba floodplain with the vast delta of the Volga River crosses the Caspian Lowland in the northwestern part. As it approaches the sea, the main branches of the Volga, 300-600 m wide, branch into numerous channels and eriks about 30 m wide. When it flows into the Caspian Sea, the river has about 800 mouths. The Volga water, saturated with industrial and agricultural runoff, poses a serious threat to the environment in the Caspian lowland. In 2000, to protect the ecosystem of swamps and nesting birds, it was created natural Park“Volga-Akhtuba floodplain”: there are more than 200 species here.

GENERAL INFORMATION
Location: in the extreme southeast of the Russian Plain, skirting the Caspian Sea from the north.
Administrative affiliation: Astrakhan region (Russia), Republic of Kalmykia (as part of the Russian Federation), Republic of Dagestan (as part of the Russian Federation), Republic of Kazakhstan.
Origin: tectonic, sedimentary rocks.
Languages: Russian, Kazakh, Kalmyk, Dagestan, Tatar, Bashkir.
Ethnic composition: Russians, Kazakhs, Kalmyks, Dagestanis, Tatars, Bashkirs.
Religions: Orthodoxy, Islam.
Monetary units: Russian ruble, Kazakhstani tenge.
Large cities: Astrakhan (Russia), Aty pay (Kazakhstan).
The largest rivers: Volga, Terek, Sulak, Ural, Emba.
The largest lakes (salty): Baskunchak, Elton, Manych-Gudilo, Tinaki.
Natural boundaries: in the west it is limited by the Stavropol, Ergeni and Volga hills, in the north - by General Syrt, in the northeast and east - by the Pre-Urape plateau, in the southeast - by the cliff of the Ustyurt plateau and the Mangyshlak peninsula, in the south - by the coast of the Caspian Sea.
FIGURES Area: about 200,000 km2.
Length: from north to south - up to 550 km, from west to east - up to 770 km.
Population: about 2 million people.
Population density: about 10 people/km2.
Lowest point: -28 m below sea level.
The most high point: Mount Bolshoye Bogdo (149.6 m above sea level).

CLIMATE
Sharply continental. Severe and little snow winter, hot summer.
Average January temperature: - 14°C in the north, -8°C on the Caspian Sea coast.
Average July temperature: +22°C in the north, +24°C on the coast of the Caspian Sea.
Average annual precipitation: less than 200 mm.
Relative humidity: 50-60%.

ECONOMY
Minerals: oil, natural gas, uranium, titanium, gold, silver, platinum, scandium, yttrium, rhenium, gallium, table salt.
Industry: mining (oil and gas, ore, salt mining).
Agriculture: plant growing (melon growing, gardening, vegetable growing), livestock breeding (pasture - sheep breeding).
Sphere of services: tourism (recreational fishing in the Volga delta), transport.
INTERESTING FACTS - The thickness of the surface salt deposits on Lake Baskunchak reaches 10-18 m. Only certain types of bacteria live in brine (saturated salt solution). Today, the extremely pure salt of Lake Baskunchak accounts for up to 80% of the total salt production in Russia: from 1.5 to 5 million tons of salt are mined here per year. The Baskunchak railway was built to export salt.
- The Kordon tract is a natural monument of regional significance (status since 1995): here in natural conditions The Mexican prickly pear cactus grows, blooming with large yellow or pale pink flowers. The cactus was planted for experimental purposes by scientists from the Khosheutov point of the Republic of Armenia in 1904-1917.
- Big Bogdo was nicknamed the “singing mountain”: during the weathering process, depressions similar to giant honeycombs were formed on the rocky cliffs. If the wind blows, the holes produce characteristic sounds of different pitches.

The Caspian Lowland is located in the southeastern part of the Russian Plain, adjacent to the Caspian Sea. In the west, the lowland is bordered by the eastern slopes of the Stavropol plateau and Ergeni, in the north by the slopes of General Syrt. In the east, the border coincides with the Pre-Ural plateau and the Northern Chink of the Ustyurt plateau. In the southern part, significant areas lie below sea level by 27m.

Most of the lowland is administratively part of the Kazakh SSR - the West Kazakhstan Territory and partly in the regions of the Volgograd, Saratov, Astrakhan and Kalmyk Autonomous Soviet Socialist Republics.

The Caspian lowland is located within a deep tectonic basin - the Caspian syneclise, founded in the Paleozoic and representing a complex and heterogeneous section of the Russian Platform. The syneclise is complicated by a number of tectonic structures IIorder. Crystalline rocks lie here at a depth of more than 3000 m and are overlain by Paleozoic and Meso-Cenozoic sediments. Within the lowlands, Permian deposits of Kungurian age are developed from ancient rocks, at the base of which lie rock salt stocks. The Permian rocks are overlain by Triassic sediments. They are overlain by Jurassic, Cretaceous and Paleogene sediments. The end of the Paleogene is characterized by orogenic movements that covered large areas. They are associated with the lowering of the lowland and the penetration of seas into its territory. The most extensive was the Akchagyl basin, which occupied almost the entire territory of the modern Caspian Sea, the Caspian Lowland and penetrated to the north. The long arm of this basin also went towards the Black Sea. In the north, the sediments of this basin are represented by thin, thick-layered clays, and near the coast - by sands; In some places there are small layers of oil shale. The total thickness of Akchagyl deposits reaches 80-100 m. The Absheron basin, which replaced the Akchagyl basin, was smaller. He left sands, conglomerates, clays with a thickness of more than 400 m. Quaternary deposits are represented by genera of marine and continental origin with a thickness of over 30 m. Marine sediments consist of clayey, sandy-clayey and sandy strata with marine fauna left by the Baku, Khozar, Lower and Upper Khvalynsk transgressions. They alternate with continental deposits - loess-like loams, sands, peat bogs, silts.

The deposits of the Lower Khvalynsk transgression are represented by chocolate clays and partly loams. The southern part was subject to the Upper Khvalynian transgression. The consequence of the Upper Khvalynian transgression are sands and sandy loams of the Upper Khvalynian age. The boundary between the two indicated transgressions runs approximately along the zero horizontal line.

Many researchers synchronize the Caspian transgressions with the glaciation periods of the Russian Plain, but due to insufficient data, the synchronization scheme is not yet sufficiently substantiated.

The Caspian lowland is characterized by peculiar structures - salt domes, characteristic of salt tectonics. The reason for their formation is associated with orogenic movements, due to which horizontally lying layers of Permian, Mesozoic and Tertiary rocks in many places are folded into small brachyanticlinal folds containing a gypsum and salt core.

Due to tangential pressure, salt masses were squeezed upward from the original deposit and broke through the overlying rocks, forming domes. Due to the redistribution of salt masses, new places of their concentration were created. Salt domes are hills 100-150 m high. m, in which gypsum and salts come to the surface (M. Bogdo, B. Bogdo, Bis-Chokho, Chapchagi, etc.). Associated with them is the existence of self-settling lakes - Elton, Baskunchak, etc., which feed saline solutions, coming from salt domes. In the Emba region, oil fields are also confined to domes composed of Jurassic and Lower Cretaceous rocks.

Orographically, the Caspian Lowland is a large depression, flat, gently inclined towards the sea. M.V. Karandeeva writes that the main type of lowland relief is the marine accumulative plain. Erosion, aeolian, suffosion and other types and forms of relief are developed on it.

The northern part of the Caspian lowland is characterized by monochromatic flat surfaces, the relative heights of which do not exceed 1.0-1.5 m. The sea flat plains are broken by depressions and numerous hillocks - marmots. Depressions are depressions with a depth of 0.3 to 2.0 m and diameter from 10 to 100 m. Their shape is usually round or oval. They stand out on the surface of the lowland not so much because of their depth as because of their fresher and greener vegetation.

Among the flat sea plains in this part of the lowland, erosional landforms are developed, which are presented in the form of hollows. The hollows sometimes stretch for tens of kilometers, in several rows. They begin in the northern part of the lowland and end in the estuaries, before reaching the Caspian Sea. Small hollows usually do not have clearly defined slopes, their width is 100 - 1000 m. An example of hollows is the Sarpinsko-Davanskaya, which stretches from Krasnoarmeysk to the south, along Ergeni, and then breaks up into branches. The hollow is covered with a thin layer of alluvium; in the Ergeni region it is currently covered with alluvium from ravines, which divides the hollow into separate depressions - lakes. The formation of hollows is associated with the flows of the receding sea. The Sarpinsko-Davanskaya hollow once served as a branch of the Volga and was fed by its waters. After the Volga deepened its channel, the Sarpinsko-Davanskaya hollow was separated from it, and its further existence occurred due to temporary flows from Ergeni. In addition to the above-described landforms, coastal landforms have been preserved within the lowland: estuaries, takyrs, etc., which are confined to the boundaries of the distribution of the Khvalyn seas.

Due to the fact that in the southern part of the lowland large areas are occupied by sand, aeolian relief prevails here. Between the Volga and Ergeni, as well as to the east on the Volga-Ural watershed, there are massifs of blowing sands - Astrakhan and Ryn-Sands. Here the sands form in places dunes 5-6 high m, and sometimes 15 m, mounds, ridges and basins. The basins have a depth of up to 8 m, and area - up to 3 km 2. Their shape is in most cases oval; the windward slopes are steep and the leeward slopes are gentle. Sand blown from the basins is deposited in the form of mounds on the surfaces adjacent to their western and northwestern sides.

Along the shores of the Caspian Sea, from the river. Emba to the mouth of the river. Kuma, there are mounds elongated almost in the latitudinal direction, the so-called Baer mounds. Their height is 7 - 10 m, width - 200-300 m and length - from 0.5 to 8 km. The width of interridge depressions reaches 400-500 m. During floods of the Volga they are filled with water. The city of Astrakhan and all villages within the Volga delta are built on these hillocks.

There is still no consensus on the origin of the mounds. Academician K. M. Baer assumed that they occurred from a catastrophically rapid flow of water during a sudden drop in the level of the Caspian Sea. I.V. Mushketov explains the origin of the mounds for various reasons: some mounds were formed due to the dislocation of the main rocks on which Caspian sediments were deposited (near Kamennoy Yar), others are a product of erosion (near Astrakhan), and others are overgrown valleys (near Enotavka). B. A. Fedorovich explains the origin of the Baer mounds by the corrosive and accumulative activity of the wind, the predominant direction of which coincides with the Voeikov axis, oriented latitude-wise in the northern Caspian region.

Salt domes, the Volga-Akhtuba and Ural valleys add variety to the lowland relief. The Volga Valley is a blooming oasis against the background of a semi-desert. The islands in the river's floodplain are green with groves of sedges, silver poplars, and willows. The Volga Valley within the lowland is incised by 20-30 m into the Lower and Upper Khvalynian marine sediments, which serve as the bedrock coast. The right bank is steep, vertical, and is strongly washed away by the river. The left main bank is located at a great distance from the riverbed. On the left bank there is a well-developed floodplain terrace (Volga-Akhtubinskaya), which extends for tens of kilometers.

The hydrographic network of the lowland is poor; Three large transit rivers flow within its boundaries: the Volga, Ural and Terek, which have no tributaries within the lowland. Rivers drain only the narrow coastal strips immediately adjacent to them. In addition to these rivers, there are several small rivers - Bolshoy and MaliyUzen, Uil, Sagiz, Kushum, which dry up in the hot season or break up into separate

closed, more or less significant basins of standing water, forming lake spills. An example is the Sarpinsky lakes, which collect water flowing from the Ergeniy, in the central part - the Kamysh-Samarsky lakes, receiving the waters of the Bolshoi and Maly Uzeni, and others. The waters of the river. In dry years, the Kums do not reach the Caspian Sea, and the waters of the river. The embs reach it only during high water. In summer in the river The Embe, like all small rivers of the semi-desert, has brackish water. Within the lowlands there are a lot of small and large salt and occasionally fresh lakes. Fresh lakes arise in depressions closed on all sides, in which melted snow waters collect.

The climate of the Caspian Lowland is characterized by the greatest continentality compared to other regions of the Russian Plain. This is due to the distance from Atlantic Ocean, with a predominance of continental air masses and with increased insolation.

In winter, the spread of the spurs of the Siberian anticyclone and the associated cold eastern winds, the frequency of which reaches 50%, play a significant role in the formation of weather conditions. Temperatures in the winter months in the Caspian region are unusually low for this latitude (from -14 in the north to -8° on the Caspian Sea coast). The same temperature conditions are observed in winter in Arkhangelsk and Leningrad. In some cases, frosts reach -30, -40°. The Caspian Sea, which freezes in the northern part, does not have a warming effect even on coastal areas. Snow cover lasts 4-5 months, but its height is small - 10-20cm.

Spring in the Caspian region is friendly and short - during the end of April and beginning of May, the temperature rises rapidly due to increased incoming radiation and the influx of warm air from the southern regions of Kazakhstan.

Summer is very hot and dry. The amount of total solar radiation for June-August reaches 50 kcal/cm 2, the same amount as in Crimea. Isotherms of the summer months are located in the latitudinal direction: in the northern part of the Caspian region average temperature July about +22°, in the south +23, +24°. The absolute maximum temperature is above +40°.

Maximum precipitation falls in the first half of summer, most often in the form of short-term showers, and is only 20-30 mm per month. Annual precipitation amounts decrease in the southeast direction from 350 to 200-150 mm. Evaporation is about 1000 mm, thus, the total moisture deficit reaches 800mm.

Droughts, characteristic of the southern and southeastern regions of the European territory of the USSR, are here of the greatest intensity and frequency (up to 30%). Dry winds blow very often, especially dry and hot ones, over the sandy semi-deserts of the southeast.

The Caspian lowland lies in the semi-desert zone, and is characterized by light chestnut solonetzic soils, the absorbent complex of which contains sodium. Thickness of humus horizons - 30-40 cm, the amount of humus is small in the upper horizons - 1-3%, and it is distributed unevenly across the soil profile. The lower part of the soil profile is saline with soluble salts. The soil cover of the semi-desert is variegated: it consists of light chestnut solonetzic soils, solonetzes and leached meadow-chestnut soils of depressions. The semi-desert is characterized by an abundance of salt lakes, salt marshes and rivers carrying salt water. Salt marshes stretch along the shores of the Caspian in a wide strip. Sands are widespread in the Astrakhan Trans-Volga region. A significant part of these sand massifs belongs to the moving category.

In the north of the Caspian lowland, the vegetation is represented by the wormwood-cereal type; As you move south, the number of grasses decreases and wormwood begins to predominate. In the south, saltworts predominate. The grass cover here is very sparse, the vegetation is low-growing, due to which it suffers less from evaporation: the plants have a very well-developed root system, allowing them to intensively use soil moisture. On slightly saline loams, the predominant importance is: white wormwood( Artemisia maritima), and on clayey, more saline soils - black wormwood ( Artemisia pauciflora); a lot of fescue ( Festuca sulcata), feather grass( Stipa capillata), thin-legged ( Koeleria gracilis). There are many tulips in spring( Tulipa schrenkii), buttercup ( Ranunculus polyrhisus), bluegrass (Roa bulbosa var vivipara). On salt licks, in addition to black wormwood, biyurgun solyanka grows ( Anabasis salsa) and lichens ( Aspicilia); in rainy times, colonies of algae appear on the salt licks, looking like black, hair-like threads pressed to the ground, more than 30 in lengthcm.

Various saltworts, black wormwood and shrubs grow on the salt marshes: tamarisk ( Tamarix romosissima), kermek ( Statice suffruticosa). Kiyak grass grows on the sands( Elymus giganteus), which is a sand fixer. Willows are found in wet hollows among the sands.( Salix rosmarinifolia), sucker ( Elaeagnus angustifolia) and other shrubs. In the depressions, among the lumpy sands, where fresh groundwater lies very close to the surface, white poplar grows( Populus alba), sedge (Ro Pulus nigra), aspen, willow ( Salix rosmarinifOla), rose hip ( Rosa cinnamomea). In the Volga floodplain there are: oak( Quercus robur), elm ( Ulmuslaevis), osokor.

Characteristic representatives of animals are: sandy or yellow gopher( Citellus fulvus), jerboa ( Alactaga elates), gerbil ( Meriones tamariscinus), hamster ( Cricetus cricetus). Saiga is found in the sands between the Volga and the Urals( Saiga tatarica), Corsac fox is widespread( Vulpes corsac).

Among the birds found: black lark( Melanocorypha yeltonieusis) and small ( Calandrella). The floodplains and deltas of rivers, especially the Volga, abound in birds. Typical for the Volga delta: great cormorant( Phalacrocorax carbo), white-tailed eagle( Haliaetus albicilla), grey goose (Apse rapseg), egret ( Egretta alba), Sultan's chicken( Porphyrio polioeephalus), pheasant ( Phasianus colchicus), mustachioed tit ( Ponurus biarmicus).

The Caspian lowland is used as pasture. The low depth of snow cover allows the use of pastures in winter time. With estuary irrigation, it is possible to obtain high yields of wheat, millet and forage grasses.

In the Volga-Akhtuba floodplain, melon growing, horticulture and gardening, sowing industrial crops and rice flourish.

In the Astrakhan Nature Reserve there is a relict plant - lotus( Nelumbium caspicum).

The Emba oil field is being developed and table salt is being extracted (lakes Baskunchak and Elton).

- Source-

Davydova, M.I. Physical geography of the USSR / M.I. Davydova [and others]. – M.: Education, 1966.- 847 p.

Post Views: 587

General characteristics of the Caspian lowland

The northern coast of the Caspian Sea is occupied by a lowland of the same name. Part of this lowland is located in Kazakhstan. It is limited from the north by General Syrt, from the west by the Volga Upland, and from the east by the Pre-Ural Plateau and Ustyurt. The occupied area is about 200 thousand square meters. km and slopes towards the sea.

The northern part of the lowland has heights of up to 100 m, and the southern part lies 28 m below sea level. This flat, drainless plain is composed of rocks of late Quaternary age. There is no permanent hydrographic network within the Caspian Lowland, although it is crossed by such large rivers as:

• Volga,
• Ural,
• Terek,
• Kuma.

In the summer, small rivers dry up or break up into basins that form lake floods, for example, Kamysh-Samarsky lakes, Sarpinsky lakes. Among the salt lakes, Elton and Baskunchak are well known to everyone.

Note 1

The largest river of the Russian Plain, the Volga, crosses the Caspian Lowland in the west. The river has the largest delta in Europe and begins north of Astrakhan. Its main branches are 300-600 m wide, branching into numerous channels and eriks, which are small watercourses up to 30 m wide. Flowing into the Caspian Sea, the Volga is divided into 800 mouths.

The climate of the territory is sharply continental, with average January temperatures ranging from -14 degrees in the north and up to -8 degrees on the coast. July temperatures vary from north to south from +22 to +24 degrees, respectively. Precipitation falls unevenly. In the southeast of the lowlands, precipitation falls no more than 150-200 mm. To the northwest their number increases to 350 mm. More evaporates than falls out. Dry winds often occur.

The vegetation cover of the Caspian lowland is characterized by steppe and semi-desert vegetation. It changes from north to south from the feather-grass-forb steppe, south of the feather-fescue steppe, to the wormwood-grass semi-desert in the south. Meadow vegetation covers large estuaries and is represented by thickets of wheatgrass. Vegetation cover is thinning out in desert areas.

The lowland vegetation is used as pasture for livestock. Melon growing, horticulture, and vegetable growing are practiced in the Volga-Akhtuba floodplain.

Table salt is mined from salt lakes. On the territory of the Caspian lowland there is the Ural-Emba oil and gas region and oil and gas production is underway.

Fauna of the Caspian Lowland

Within Russia, on the coast of the Caspian Sea, the Volga-Ural interfluve stands out, where the best pastures are located, hunting and fishing are developed, as well as the Ural-Emba interfluve with known oil and gas reserves.

The deserts of the Caspian lowland are home to 56 species of mammals, 278 species of birds, 18 species of amphibians and reptiles. A number of species are classified as rare and endangered. The Caspian coast is of great importance for migratory and wintering birds. According to experts, about 1.5 million waterfowl winter within the southern Caspian Sea.

The northern and northeastern Caspian coast is a migration area for about 3 million shorebirds. 2.5 thousand pairs of mute swans, 500 pairs of gray geese, which gather here to molt in the summer, and more than 2 thousand pairs of dabbling ducks nest in the reed thickets.

In this area, 20 thousand pairs of gulls and terns, and up to 1 thousand pairs of pink pelicans have made their nesting grounds.

Note 2

The main population of commercial ungulate mammals is concentrated in the Volga-Ural interfluve - the saiga, the population of which numbers up to 300 animals. At the beginning of 2009, the Nature Management and Environmental Protection Service noted that groups of 10-12 saigas were recorded in the Akhtuba area. In the Volgograd region their number was up to 100 individuals. In the summer of the same year, 1.5 thousand saigas were recorded entering from the territory of Kazakhstan. This indicates their spontaneous movement from one territory to another, which greatly complicates full monitoring and protection.

The Caspian seal appears in the waters of the northern part of the Caspian Sea in winter and spring, the population of which ranges from 450-500 thousand individuals. Five species of animals are numerous:

• fox,
• steppe polecat,
• wolf,
• saiga,
• Eversman's hamster.

More than 30 species are common in the region; the remaining species are found in the Caspian deserts.

The endemic species include the long-spined hedgehog - rare view insectivores, with a body weight of up to 750 g and leading a nocturnal lifestyle, the Ustyurt mountain sheep of the bovid family of the artiodactyl order, the honey badger - the only species in the mustelidae family, the Caspian seal - an inhabitant of the entire water area of ​​the Caspian Sea, but in the cold season it concentrates on the northern coast of the Caspian Sea, Bobrinsky's leather jacket - bat order of bats. These animal species are endangered.

Very low level of numbers and density of animals such as gerbils and jerboas. IN last years it is up to 6 individuals per 1 hectare. The number of gophers is even lower - 3 individuals per 1 hectare. A significant role in the region is played not only by valuable commercial species– saiga, fox, steppe polecat, but also those who are carriers infectious diseases– jumping jerboa, gray hamster, gerbils.

Environmental problems of the territory

One of environmental problems territory is associated with rising levels of the Caspian Sea. The result of this was the flooding of vast areas of the Caspian lowland, flooding of port facilities, settlements, transport communications, etc. The rapid growth of cities, the saturation of industrial enterprises, the activities of which contribute to the pollution of the Volga and its tributaries, the plowing of land and improper agricultural practices accelerate development erosion processes.

The territory of the Republic of Kalmykia is overloaded with pasture lands, where haphazard grazing of livestock is carried out. The result is desertification and loss of grass. In order to prevent desertification of Kalmyk lands, the “Federal Program to Combat Desertification of the Territory” is in effect. There are first positive results in resolving this issue.

Another pressing problem is the pollution of the Volga water. Flowing through the entire Russian Plain and receiving untreated water from enterprises along its entire length, the river carries it into the Caspian Sea, creating an unfavorable environmental situation in the area. As a result of pollution of the Caspian Sea, its biodiversity is reduced, alien bacteria penetrate, and pollution from land-based sources occurs.

Note 3

The main pollutant is oil, which suppresses the development of phytobenthos and phytoplankton. The sea served as a testing ground for the introduction of new species, but with the penetration of alien organisms from other seas, events began to develop according to a dramatic scenario. An example of drama is the mass reproduction of the ctenophore Mnemiopsis. Appearing for the first time in the Sea of ​​Azov, it literally devastated it, and penetration into the Caspian Sea was not difficult. Feeding on zooplankton, the ctenophore destroys the food base of Caspian fish. Not having natural enemies, rapidly multiplying, it became out of competition with other consumers of plankton.

Oil pollution negatively affects heat-gas-moisture exchange between the water surface and the air basin. The rate of water evaporation decreases several times.

Oil pollution affects waterfowl, whose feathers lose their water-repellent and heat-insulating properties. As a result, birds die in large numbers. Oil spills also affect other animals of the Caspian lowland, for example, the number of sea pike perch is declining.

The construction of hydroelectric power stations on rivers also leads to undesirable consequences - fish are deprived of their natural habitats, river beds begin to silt. Fortunately, a protected area has been created in the northern Caspian Sea and an appropriate regime has been introduced, which prohibits any geophysical work.

Note 4

To eliminate or at least somewhat mitigate negative environmental phenomena, large investments are required. But, unfortunately, enterprises do not have available funds for these purposes. The Caspian Sea and its northern shores continue to gradually become polluted

Caspian lowland, the geographical location of which is determined by the bottom area ancient sea, - a flat area with flat stretches of land, slightly inclined towards the largest salt lake on the planet - the Caspian Sea. There are many attractions of various origins located on the plain. The indigenous inhabitants are Kalmyks.

Short description

This area is practically waterless, with small mountains and hills visible in places. These are the Small and Large Bogdo, the Inder Mountains. The territory of the Caspian lowland extends 700 km in length and 500 km in width. Occupies about 200 sq. km of total area. It is surrounded on several sides by the hills of the Volga region, the Pre-Ural plateau, and also by hills. The coast from the north, from the southeast side and Kazakhstan in the west are the boundaries of the territory called the Caspian Lowland. On the map of the hemispheres its location can be seen more accurately.

The river and ravine network is poorly developed. The lowland consists of clay and sand. The terrain of the territory is characterized by movement of the earth's crust, which is accompanied by the growth of ravines, craters, and landslides.

Inland waters

The Caspian lowland is crossed by six large rivers (Ural, Volga, Terek, Emba, Kuma, Sulak) and several small watercourses. The latter often dry out completely in the summer season, forming many pits. The Volga is the most abundant and longest river of the plain. All water flows are fed by snow and groundwater. Most of these reservoirs are fresh, but there are also salty ones. Most famous salt Lake of those places is Inderskoye Lake, its area is 75 square meters. km.

Structural features

The Caspian lowland, the height of which varies mainly within 100 m, also has a minimum value, namely on the southern side it rises by only 25 m. The geological structure of the territory consists of several large tectonic structures: the Ergeninskaya Upland, the Caspian deep depression, and the Nogai , Terskoy. Once upon a time, the territory of the plain was constantly flooded by sea waters, as a result of which clay and loamy deposits remained on the north and sandy deposits on the south.

Unique Baer mounds

The Caspian lowland has small and large depressions, estuaries, spits, hollows, and along the seashore there are Baer mounds, stretching in a strip. They begin between the mouths and the Emba. Their height varies from 10 to 45 m, their length is about 25 km, and their width is 200-300 m. The distance between the ridges of the Baer mounds is 1-2 km. This relief formation looks like artificially made sea waves. Their peaks are wide and their slopes are gentle. They can be described in different ways, due to the heterogeneity of addition. In the first case, they are composed of late Khvalynian sand, and in the second - early Khvalynian clay, covered with sand.

The origin of these mounds is still unclear. There are a number of hypotheses:

• The first of which is the result of some shallowing of the Caspian Sea.
• The second talks about tectonic origin.
• The third indicates glacial lakes.

But there are allegations that these versions are untenable. Due to the location of the Baer mounds near the coast, a change in their structure and clarity is observed. Losing their forms closer to the north, they are replaced by other reliefs.

Climate

The Caspian lowland is an area where the constant “guests” are anticyclones that come from the depths of Asia. But with cyclones it’s more difficult, because of this the climate here is very dry. Winters are relatively harsh and have little snow, temperatures vary from -8 o C to -14 o C. Summers are quite hot for this area. July temperature: +22… +23 o C. 150-200 mm of precipitation falls on the south-eastern side, and 350 mm on the north-western side. Evaporation rate 1000 mm. Humidification is extremely insufficient. Dry winds are characteristic and they form hills called dunes.

Soil Features

The Caspian lowland, or rather its lands, have several colors: from light chestnut to desert-steppe brown. The soil here is highly saline. In the north there are steppes with cereals and wormwood; to the south there are semi-deserts and deserts, where wormwood mainly grows. Pastures predominate among the land. Arable land occupies less than 20% of the entire territory, mainly near the Volga-Akhtuba floodplain. Here people grow and do gardening and vegetable growing. Oil and gas production has been established in the Ural-Emba oil and gas region, and table salt is extracted in Baskunchak. Baskunchak is also rich in gypsum and limestone, the annual production of which is about 50 tons.

Animal world

The fauna is influenced by the European fauna. The Caspian lowland in the north is inhabited by ferrets, marmots, raccoons, and water rats. Fish fishing is well developed: sturgeon, stellate sturgeon and others. Local seals are considered the most valuable animals. Along the banks, in the Turgai thickets, there are many birds, goitered gazelles, foxes, long-eared hedgehogs, jerboas, mice, and larks also live there.

The famous Black Lands reserve, created in a place where there are practically no people living and no water, is located in the Caspian lowland, a most interesting object from the point of view of science and geotourism. The Caspian Lowland is a territory located at the extreme point of the southeast of the Russian Plain and encircling the Caspian Sea. In the southeast, the black lands or Khar-Gazr in Kalmyk, approaches the Volga delta, this is where another interesting natural object- Baer mounds (in honor of Ak.

Where is the Caspian lowland located on the physical map?

K.M. Burr, who discovered this miracle of nature), which are sand ridges up to 45 meters high and up to 300 meters wide, the length of which is several kilometers. Between the hillocks you can see ilmens, small lakes overgrown with grass; any activity is prohibited here, as it can destroy these delightful creations of nature.

On the territory of the Caspian lowland there is the Volga-Akhtuba floodplain, where the Great Russian River, dividing into many branches, there are about 800 of them, flows into the Caspian Sea and ends its course. A natural park of the same name was established in this territory with the aim of protecting the ecosystem and nests of more than 200 species of birds. This place is extremely popular among fishermen, because the variety and size of underwater inhabitants can surprise even the most experienced fisherman! Therefore, when traveling in the Volga Delta, you should definitely take a selfie with a huge catch, especially since fishing promotions in July will allow you to save significantly on this type of vacation. Another miracle of nature located in the Caspian lowland can be safely called the famous salt lake Baskunchak, which is rightfully considered a bottomless bowl of salt. In addition to the above-mentioned attractions created by nature, it should also be noted: the Lotus Valley, the Burley Sands reserve, the Kordon tract, the Manych-Gudilo nature reserve and, of course, the Big Bogdo salt dome.

In addition to natural attractions, the region is also rich in historical ones. Among the architectural monuments, it is worth noting such as the Devil's Settlement, located in the Ikryaninsky district, erected during the time of the Golden Horde, Sarai-Batu, or as it is also called Selitrennoye Gordische, is a fortified complex built around the beginning of the 13th century. It is also worth noting the burials discovered here dating back to the Bronze Age and more recent monuments, such as the Khosheutovsky khurul, a monument to the wars that defeated Napoleon. Also on the territory of cities located in the Caspian lowland there are many cultural and religious buildings built in different eras.

The most big city Astrakhan, the center of the region of the same name, is located here; most of the enterprises involved in the extraction and processing of minerals, which the lowland area is rich in, are concentrated here. And oil, uranium, gas, and many industrial and precious metals are mined here.
Part of the Caspian lowland is located on the territory of Kazakhstan; here the largest regional center is the city of Atyrau, considered the oil capital of all of Kazakhstan.

The Caspian lowland is not only the “Black Land” where nothing grows except wormwood, but also the most fertile lands of the Astrakhan region, where the climate allows you to grow some of the most delicious watermelons. The list of attractions in the region is not limited to the list above; even ten similar articles would not be enough to describe them all; such a volume of printed information is unlikely to be adequately absorbed, therefore, if you are interested, we advise you to visit this unique place located on the territory of our Motherland. Good luck.

Tags: travelRussia

The relief of the Saratov region is varied; in one article we cannot show you how different it is from each other in different parts of the region, so we will write about each type of relief separately. In this article you will learn everything about the Caspian Lowland, including its geological structure and hydrography. Read the article about the geological structure of the Saratov region in our article: Geological structure of the Saratov region.

Caspian lowland is located in the basin of the lower reaches of the Bolshoi and Maly Uzeni rivers and occupies the southeastern part of the Saratov region.

Caspian Lowland: description and features

Geologically, this lowland is the youngest - it is a marine accumulative plain of early Khvalynian age. Its surface is smooth, slightly hilly and slightly dissected. Absolute elevations: in the north - from 45-50 m, in the south - 20-25 m. Flat, featureless watersheds up to 50 m high are composed of sea sands, sandy loams and “chocolate” clays of early Khvalynian age, lying almost horizontally.

On its surface there are many estuaries, as well as small “steppe saucers” (depressions) with a diameter of 1.5-2 m. Some estuaries due to the accumulation melt water form lakes and wetlands.

The relief of the region is characterized by modern movement of the earth's crust. It is accompanied by increased erosion processes (growth of ravines, landslides, sinkholes, etc.) and leveling of the relief. Also read our article about the Relief of the Saratov region.

The lowland is separated from the Syrtovaya Plain to the north by a well-defined abrasive pre-Syrtove ledge, which has the shape of a straight slope 50-80 m wide, less often 20 m. The surface of the plain has a slight slope to the south and southeast.

Estuaries, suffoeic depressions, saucer-shaped depressions, mounds of biogenic origin, coastal ramparts, lakes, differing in shape, size, and duration of the waterway, are widespread. The river and ravine-gully network on it is poorly developed. The lowland is composed of clays, loams, and sands. The depth of valley incision does not exceed 2-5 m. Erosion gives way to accumulation.

During the Quaternary period, the Caspian lowland was the scene of several transgressions of the Caspian Sea. The largest of them was the early Prague, when the sea covered the entire lowland. The boundary of this transgression in the north is clearly marked by an abrasion scarp. Since then, erosion and other processes have little changed the original appearance of the sea plain.

The Caspian lowland is confined to the Caspian syneclise and is currently an area of ​​subsidence and accumulation of a thick (up to 17 km) cover of sedimentary deposits. Against the background of the general subsidence, areas of intense uplift stand out in places where salt domes and massifs develop.

When writing the article, the following sources were used: Geography of the Saratov region. Saratov, 1997, sargidro.narod.ru; Photo: 5klass.net

Sights of Russia: Caspian Lowland

Abstract on the topic:

Caspian lowland

Plan:

Introduction
• 1Geographical location
• 2Geological structure
• 3Climate and vegetation
• 4Economic significance
• 5Source

Introduction

Caspian lowland- a lowland located on the East European Plain, surrounding the northern part of the Caspian Sea.

1. Geographical location

The Caspian lowland is bordered in the north by General Syrt, in the west by the Volga Upland and Ergeni, in the east by the Pre-Ural Plateau and Ustyurt. The area of ​​the lowland is about 200 thousand km². The height above sea level is up to 149m, the southern part of the lowland lies below sea level (up to −28m).

The Caspian lowland is a flat surface, gently inclined towards the sea, among which rise individual hills - the Inder Mountains, Big Bogdo, Small Bogdo and others.

The Caspian lowland is crossed by the rivers Ural, Volga, Terek, Kuma and others. Small rivers (Bolshoy and Maly Uzen, Wil, Sagiz) dry up in the summer or break up into a number of basins, forming lake spills - Kamysh-Samara lakes, Sarpinsky lakes. There are many salt lakes (Baskunchak, Elton, etc.).

2. Geological structure

The Caspian lowland includes several large tectonic structures (Caspian syneclise, Ergeninsky uplift, Nogai and Tersk depressions). In Quaternary times, the lowland was repeatedly flooded by the sea, which left clayey and loamy deposits in the northern part and sandy deposits in the southern part.

The surface of the Caspian lowland is characterized by micro- and mesoforms in the form of depressions, estuaries, spits, hollows, in the south - eolian forms, and along the coast of the Caspian Sea - a strip of Baer hillocks.

3. Climate and vegetation

The climate is sharply continental. Average temperatures in January range from −14° in the north to −8° on the coast; in July, respectively, +22°, +23°. Precipitation ranges from 200-150mm in the southeast to 350mm in the northwest, evaporation is about 1000mm. Dry winds are frequent.

The soils and vegetation of the Caspian lowland are characterized by great complexity. Salt licks and solonchaks are often found.

In the north there are wormwood-grass steppes on light chestnut soils, in the south there are semi-deserts and deserts on brown and sandy soils with a predominance of wormwood.

4.

Map of the Caspian lowland

Economic significance

Used as pasture.

In the Volga-Akhtuba floodplain, melon growing, gardening, and vegetable growing are widespread.

Oil and gas production (Caspian oil and gas province), in lakes - extraction of table salt (lakes Baskunchak, Elton, etc.).

5. Source

Grigoriev A.A. Brief geographical encyclopedia. Volume 3. - M.: Soviet encyclopedia, 1962. - P.580.

Satellite photograph of the lower Volga, Caspian Lowland and northern Caspian Sea

Caspian lowland- lowland surrounding the northern part of the Caspian Sea.

Geographical position

The Caspian lowland is bordered in the north by the Common Syrt, in the west by the Volga Upland and Ergeni, in the east by the Pre-Ural plateau and Ustyurt. The area is about 200 thousand km². The height is up to 149m, the southern part of the lowland lies below ocean level and is −28m.

The Caspian lowland is crossed by the rivers Ural, Volga, Terek, Kuma; small rivers (B. and M. Uzen, Wil, Sagiz) dry up in the summer or break up into a number of basins, forming lake floods - Kamysh-Samara lakes, Sarpinsky lakes. There are many salt lakes (Baskunchak, Elton, etc.).

The Caspian lowland is a flat surface, gently inclined towards the sea, among which rise individual hills - the Inderskpe Mountains, Big Bogdo, Small Bogdo and others.

Map on Google.Earth

Geological structure

The Caspian lowland includes several large tectonic structures (Caspian syneclise, Ergeninsky uplift, Nogai and Tersk depressions). In Quaternary times it was repeatedly flooded by the sea, which left clay and loamy deposits in the northern part and sandy deposits in the southern part.

The surface of the Caspian lowland is characterized by micro- and mesoforms in the form of depressions, estuaries, spits, hollows, in the south - aeolian forms, and along the coast of the Caspian Sea - a strip of Baer hillocks.

Climatic conditions

The climate is dry, continental.

Caspian lowland

Average temperatures in January range from −14° in the north to −8° on the coast; in July, respectively, +22°, +23°. Precipitation ranges from 200-150mm in the southeast to 350mm in the northwest, evaporation is about 1000mm. Dry winds are frequent.

The soils and vegetation of the Caspian lowland are characterized by great complexity. The soils are light chestnut, solonetzic, and there are solonetzes and solonchaks. In the north there is wormwood-cereal vegetation, to the south the number of cereals decreases, and wormwood begins to predominate. Used as pasture. In the Volga-Akhtuba floodplain there is melon growing, horticulture, and vegetable growing. Oil fields (Emben oil region), table salt in lakes (Baskunchak, Elton lakes, etc.).

Source

Grigoriev A.A. Volume 3 // Concise geographical encyclopedia. - M.: Soviet Encyclopedia, 1962. - P. 580 p.

§ 24. Plains (textbook)

§ 24. Plains

1.Remember how plains are indicated on the map.

2.What landforms are common in your area?

Surface of plains. Our planet is dominated by flat terrain. This is clearly visible on the physical map of the hemispheres.

There are plains flat. The surface is smooth, there are no noticeable ascents and descents. Eat rolling plains, Where increases alternate with decreases. However, such inequalities have a relative height of no more than 200 m. Therefore, plains- These are relatively flat areas earth's surface with slight variations in height. Most of the plains of the globe are huge in size. Their names reflect this: Great Chinese Plain in Eurasia, Great Plains V North America. On one Eastern European Plain The territory of many states fit in - Ukraine, Belarus, Moldova, Lithuania, Latvia, Estonia and Russia (western part).

Heights of the plains. Based on the altitude above sea level, the plains are divided into low (lowlands), high (highlands) and high (Plateau).

Lowlands have absolute heights of up to 200 m.

For example, West Siberian Plain with a flat surface in Eurasia. On the earth's surface there are lowlands located even below sea level. For example, Caspian lowland lies 28 m below sea level.

Hills— These are plains with absolute heights from 200 to 500 m. Hills include, for example Podolsk in Ukraine.

Plateau— These are also plains, only they are quite high - more than 500 m above sea level. Examples are Central Siberian Plateau and plateaus Dean in Asia.

The flat terrain of Ukraine is created by alternating lowlands and hills. By physical map It is easy to determine where they are located: the yellowish color of the hills differs from the green color indicating the lowlands. So, Pridneprovskayaelevation located in the western part, and Black Sea Lowland lies in the south of the country. However, in nature it is difficult to notice the transition from one type of plain to another. If you travel, for example, from Odessa to Vinnitsa, the terrain will gradually rise and the traveler, unnoticed by himself, will continue his journey no longer on the lowlands, but on the hills. Changes in absolute altitudes can only be determined using special instruments.

Education of the plains. Plains can form as a result of the seabed being raised and freed from water. This is observed during vertical movements of the earth's crust. Such plains are called primary. For example, Prichernomorskayalowland was once a section of the bottom of the Black Sea.

Secondaryplains are formed in different ways. Some of them are created by river sediments (sands, loams), for a long time accumulated in depressions of the earth's crust. Their surface is flat or slightly wavy. So, Mesopotamian lowland formed by sediments of the Tigris and Euphrates rivers. Plains can also arise in place of mountains when, under the influence of external processes, their peaks and slopes are destroyed, and basins are filled with debris. Then the mountainous terrain gradually levels out and turns into a hilly plain. An example is Kazakh small hills— A high plain, among which rise individual remnants of mountain ranges. Ukraine is such a plain Donetsk Ridge.

Plains are usually covered with thick sedimentary rocks: sand, clay, forests, gravel, limestone. Deep beneath them lie igneous and metamorphic rocks: granite and gneiss. In some places they come to the surface. Layers of sedimentary rocks lie horizontally or with a slight slope. You can determine in which direction the plain is tilted both on the ground and on the map by the direction of the rivers.

Changes in the surface of the plains. Plains change under the influence of internal and external processes. Plains, as a rule, lie on platforms - ancient, leveled, stable sections of lithospheric plates. Therefore, internal processes manifest themselves there mainly in slow vertical movements.

External processes are associated with the work of water and wind. Where there is enough flowing water, river valleys and ravines are formed. Ravines destroy areas of fertile land. To combat them, people plant bushes and trees. In deserts where it is dry, the surface of the plains changes due to weathering, as well as the action of the wind, which creates sand ridges, dunes and dunes. Now significant external force became and economic activity person. During the construction of cities and roads, ravines are filled up and embankments are created. When mining minerals, quarries appear, and hills of waste rock grow near the mines - waste heaps Unfortunately, human transformation of a natural surface often has negative consequences. Careless economic activity can lead to the emergence of a dense network of ravines, turning fertile lands into wastelands.

Questions and tasks

1.What are called plains? What kind of surface can plains have?

2.How are plains differentiated by height?

3. Using the height scale in the atlas, determine what color each type of plain is indicated by height. Give examples of each type of plain.

4.What kind of plains are there in Ukraine?

5. The Dnieper divides Ukraine into Right Bank and Left Bank. Using the physical map of Ukraine, determine which one is higher.

6.How are plains formed?

7. Under the influence of what processes can the surface of the plains change?