The Caspian lowland on the physical map of the world. The Caspian lowland is the Crown of the Caspian Sea. Sights of Russia: Caspian lowland

BLACK LAND OF THE CASPIAN DEPRESSION
The Black Lands (Kalmyk. "Khar 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 toponym, but the word "black" does not mean only color.

On aerial photographs, 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 below the level of the World Ocean by almost 30 m, and in the northern part the height rises to 150 m above the ocean level (mountains Indersky, Big and Small Bogdo). The Caspian lowland is located within the boundaries of the Caspian syneclise (from the ancient Greek “together” and “inclination”) - a gentle trough of the earth's crust that formed in the Paleozoic. The folded basement of the syneclise lies at a depth of 3000-4000 m and is covered with a layer of sedimentary deposits, the thickness of which reaches here the greatest depth 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 Kumo-Manych depression,

The Ergeninsky 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 is of little use for life. Here, the population density is extremely low - less than 4 people / km2. In the summer, 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 stint 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 for the extraction of uranium, titanium, precious metals - gold, silver and platinum, rare earth elements - scandium, yttrium, rhenium, gallium.

Active development of deposits also has a negative effect: the surface of the Black Lands quickly turns into an anthropogenic desert (especially considering that soils began to form here only 4-5 thousand years ago, there is almost no turf). In order to preserve the local ecosystem, the state biosphere reserve "Chernye Zemli" was created.

In the northeast, "Khar Gazr" descends into the Volga delta, to the Caspian Sea, where strips of Baer hillocks stretch along the coast (first described in 1866 by academician K. M. Baer) - sandy ridges of regular shape from 6 to 45 m high, wide 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 a 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 eriki, about 30 m wide. At the confluence with the Caspian Sea, the river has about 800 mouths. The Volga water, saturated with industrial and agricultural effluents, poses a serious danger to the environment in the Caspian lowland. In 2000, to protect the ecosystem of swamps and nesting birds, the natural park "Volga-Akhtuba floodplain" was created: there are more than 200 species of them.

GENERAL INFORMATION
Location: in the extreme south-east of the Russian Plain, around the Caspian Sea from the north.
Administrative affiliation: Astrakhan region (Russia), Republic of Kalmykia (part of the Russian Federation), Republic of Dagestan (part of the Russian Federation), Republic of Kazakhstan.
Origin: tectonic, deposition of sedimentary rocks.
Languages: Russian, Kazakh, Kalmyk, Dagestan, Tatar, Bashkir.
Ethnic composition: Russians, Kazakhs, Kalmyks, Dagestanis, Tatars, Bashkirs.
Religions: Orthodoxy, Islam.
Monetary units: Russian ruble, Kazakh tenge.
Large cities: Astrakhan (Russia), Aty pay (Kazakhstan).
The largest rivers: Volga, Terek, Sulak, Ural, Emba.
The largest lakes (salt): Baskunchak, Elton, Manych-Gudilo, Tinaki.
Natural borders: in the west it is bounded by the uplands of Stavropol, Ergen and Volga, in the north - by the General Syrt, in the northeast and east - by the Pre-Durap 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 highest point: Mount Bolshoye Bogdo (149.6 m a.s.l.).

CLIMATE
Sharply continental. Severe and little snowy winter, hot summer.
Average January temperature: -14°С in the north, -8°С on the coast of the Caspian Sea.
Average temperature in July: +22°С in the north, +24°С on the coast of the Caspian Sea.
Average annual precipitation: less than 200 mm.
Relative air 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), animal husbandry (pasture - sheep breeding).
Services: tourism (amateur fishing in the Volga delta), transport.
CURIOUS FACTS - The thickness of the surface deposits of salt on Lake Baskunchak reaches 10-18 m. Only certain types of bacteria live in brine (saturated saline 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 annually. The Baskunchak railway was built for the export of salt.
- The Cordon tract is a natural monument of regional significance (status since 1995): here, under natural conditions, the Mexican prickly pear cactus grows, blooming with large yellow or pale pink flowers. The cactus was planted for experimental purposes by the scientists of the Khosheut station of the Republic of Armenia in 1904-1917.
- Big Bogdo was nicknamed the "singing mountain": in the process of weathering, depressions similar to giant honeycombs formed on the rocky cliffs. If the wind blows, the holes make characteristic sounds of different heights.

The Caspian lowland goes around the north - the largest endorheic lake in the world. The lowland itself is mostly waterless, relatively flat, gently inclined towards the sea space (the bottom of the ancient sea), receiving a small amount of moisture in the form of rain, only 10% of the territory of which is available for irrigation. The river, Terek, Sulak, Kuma, Emba and smaller rivers flow along the lowland to the Caspian Sea, in summer they dry up in places and form chains of small lakes.

On aerial photographs, 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 below the level of the World Ocean by almost 30 m, and in the northern part the height rises to 150 m above the ocean level (mountains Indersky, Big and Small Bogdo). The Caspian lowland is located within the boundaries of the Caspian syneclise (from ancient Greek “together” and “inclination”) - a gentle trough of the earth's crust that formed in the Paleozoic. The folded basement of the syneclise lies at a depth of 3000-4000 m and is covered with a layer of sedimentary deposits, the thickness of which reaches here the greatest depth for the Russian platform. In ancient times, the Caspian lowland was part of the World Ocean, and 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 Kumo-Manych depression, the Ergeninskaya upland and the Volga (at the junction with the Sarpinsky lowland), there 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 is of little use for life. There is an extremely low population density - less than 4 people / km 2. In the summer, 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 stint 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 for the extraction of uranium, titanium, precious metals - gold, silver and platinum, rare earth elements - scandium, yttrium, rhenium, gallium.
Active development of deposits also has a negative effect: the surface of the Black Lands quickly turns into an anthropogenic desert (especially considering that soils began to form here only 4-5 thousand years ago, there is almost no turf). In order to preserve the local ecosystem, the state biosphere reserve "Chernye Zemli" was created.
In the northeast, "Khar Gazr" descends into the Volga delta, to the Caspian Sea, where strips of Baer hillocks stretch along the coast (first described in 1866 by academician K.M. Baer) - sandy ridges of regular shape from 6 to 45 m high, wide 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.
with a 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 eriki, about 30 m wide. At the confluence with the Caspian Sea, the river has about 800 mouths. The Volga water, saturated with industrial and agricultural effluents, poses a serious danger to the environment in the Caspian lowland.
In 2000, to protect the ecosystem of swamps and nesting birds, the natural park "Volga-Akhtuba floodplain" was created: there are more than 200 species of them.
People have settled in these places for a long time. Bronze Age burials were found in the area of ​​the Turtle farm (Volga-Akhtuba floodplain). In ancient times, transit trade was of great importance for the region: one of the routes of the Great Silk Road passed here.
The dry climate of the Caspian lowland and a large number of sunny days a year contribute to the development of melon growing, horticulture and vegetable growing in the Volga-Akhtuba floodplain.
Astrakhan watermelons are considered the best in Russia and Kazakhstan. All other lands are suitable only for pasture or unsuitable at all. An important sector of the economy of the Caspian lowland is the extraction of table salt, mainly in salt lakes and Elton. Salt lakes are among the protected natural objects in the territory.
In general, the landscape, plants (wormwood, feather grass, fescue, wheatgrass, etc.) and animals of semi-deserts and deserts are characteristic of the entire lowland. Among mammals, rodents and hedgehogs predominate; predators feed on them - wolves, foxes, jackals; preserved steppe antelopes - saigas, in the south - wild boars; birds - eagles, flamingos, pelicans, Siberian Cranes, larks, gray cranes, ducks, geese, etc. There are many reptiles, for example, a marsh turtle, muzzle, steppe viper, etc.
The name of Lake Baskunchak in the Astrakhan region is translated from Turkic as “sunny” or “glorious”. The reason is that nearby is Mount Big Bogdo - an object of religious worship of the Kalmyks. The area of ​​the lake is about 100 km2, and it is fed by salt springs. In the summer, the lake dries up and becomes like a snowy desert with a hard and dry salt cover. There is an unusually high amount of table salt, which makes up to 98% of all lake sediments. Salt reserves in Baskunchak are considered inexhaustible.
A feature of the relief characteristic of the Caspian lowland is salt domes, one of which is Mount Big Bogdo, 149 m high. This hill near Lake Baskunchak is called a “mountain” because it stands out sharply in the middle of a flat plain. It was formed as a result of the rise of plastic salt-bearing strata.
Every year Mount Big Bogdo becomes higher and higher: the salt dome located inside the mountain annually increases by about 1 mm. "Bogdo" in the languages ​​of the Mongols and Kalmyks is something sublime, majestic, in some cases the holiness of the object is implied. The local population is sure that Mount Big Bogdo was consecrated by the Dalai Lama - the high priest of the Buddhist Church in Tibet - and they come to worship it.
At present, the largest cities of the Caspian lowland are the Russian and Kazakh Atyrau.
Astrakhan - the administrative center of the eponymous region of the Russian Federation - stands in the upper part of the Volga delta, stretching along both banks of the river for 45 km. In the VIII-X centuries. Here was Itil - the capital of the Khazar Khaganate. Itil is also the name of the Volga among the Arabs, and later - among the Tatars and Bashkirs. In the XIV century. Astrakhan (Khadzhi-Tarkhan) was the headquarters of the khans of the Golden Horde. In 1556, Tsar Ivan the Terrible (1530-1584) annexed the Astrakhan Khanate to Russia. In 1692, a plague epidemic killed more than 10 thousand people out of 16 thousand inhabitants of the city. Currently, Astrakhan is a major river port and a gas production center.
Atyrau (until 1991 - Guryev) is the regional center of the Atyrau region of the Republic of Kazakhstan, standing on the banks of the Ural River. Founded in the 17th century. as a Cossack prison (fortification). In 1991 it was renamed to Atyrau. It is considered the "oil capital" of Kazakhstan: oil production began here in the 17th century.

general information

Location: in the extreme south-east of the Russian Plain, around the Caspian Sea from the north.

Administrative affiliation: Astrakhan Region (Russia), Republic of Kalmykia (part of the Russian Federation), Republic of Dagestan (part of the Russian Federation), Republic of Kazakhstan.

Origin: tectonic, deposition of sedimentary rocks.

Languages: Russian, Kazakh, Kalmyk, Dagestan, Tatar, Bashkir.

Ethnic composition: Russians, Kazakhs, Kalmyks, Dagestanis, Tatars, Bashkirs.

Religions: Orthodoxy, Islam.
Monetary units: Russian ruble, Kazakh tenge.

Large cities: Astrakhan (Russia), Atyrau (Kazakhstan).

Major rivers: Volga, Terek, Sulak, Ural, Emba.

The largest lakes (salty): Baskunchak, Elton, Manych-Gudilo, Tinaki.

Natural borders: in the west it is bounded by the uplands of Stavropol, Ergen and Volga, in the north - by General Syrt, in the northeast and east - by the Pre-Durap 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.

Numbers

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 / km 2.

lowest point:-28 m below sea level.

highest point: Mount Big Bogdo (149.6 m above sea level).

Climate and weather

Sharply continental.

Severe and little snowy winter, hot summer.

January average temperature:-14°С in the north, -8°С on the coast of the Caspian Sea.
July average temperature:-22°С in the north, +24°С on the coast of the Caspian Sea.
Average annual rainfall: 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, horticulture, vegetable growing), animal husbandry (pasture - sheep breeding).
Services: tourism (amateur fishing in the Volga delta), transport.

Attractions

■ Natural: natural park "Volga-Akhtuba floodplain" and the Volga delta, Astrakhan nature reserve, natural biosphere reserve "Chernye zemli", nature reserve "Manych-Gudilo" (salt lake), Kumo-Manych depression (border between Europe and Asia), strip of Baer Bugrov, Mount Bolshoe Bogdo (salt dome), Bogdinsko-Baskunchaksky Reserve (Lake Baskunchak, Baskunchakskaya Cave, Surikovskaya Balka), Lotus Valley in Astrakhan in the Volga Delta, Kordon tract, Sands of Burley nature reserve (Kharabalinsky district).
■ historical: burials of the Bronze Age (Turtle farm, Volga-Akhtuba floodplain), the Golden Horde settlement of Devil's settlement (Ikryaninsky district, XIII-XIV centuries), Saray-Batu - Selitrennoe settlement (1242-1254), settlement "Self-made" - Itil (XI-XIII centuries), Kalmyk temple-monument Khosheut khurul in honor of the victory of Russian troops over Napoleon in the Patriotic War of 1812 (1814-1818).
■ Cultural: the museum "Russian watermelon" (Kamyzyak), the mausoleum of the poet Kurmangazy (1818-1889) and the Museum of the culture of the Kazakh people (the village of Altynzhar, Astrakhan region).
■ Cult: Church of the Intercession of the Most Holy Theotokos (village of Solenoye Zaimishche, Astrakhan Region, 1906), Church of the Nativity of the Most Holy Theotokos (village of Nikolskoye, Astrakhan Region, late 19th - early 20th centuries).

Curious facts

■ The thickness of the surface deposits of salt on Lake Baskunchak reaches 10-18 m. Only certain types of bacteria live in brine (saturated saline 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 annually. The Baskunchak railway was built for the export of salt.
■ The Cordon tract is a natural monument of regional significance (status since 1995): here the Mexican prickly pear cactus grows in natural conditions, blooming with large yellow or pale pink flowers. The cactus was planted for experimental purposes by the scientists of the Khosheut station of the Republic of Armenia in 1904-1917.
■ Big Bogdo was nicknamed the "singing mountain": in the process of weathering, depressions similar to giant honeycombs formed on the rocky cliffs. If the wind blows, the holes make characteristic sounds of different heights.

■ A lotus flower grows in the Astrakhan Nature Reserve. It has been known in the Volga delta for more than 200 years, here it is called the Caspian rose. Lotus blooms from mid-July to September. According to one version, the lotus was brought here by birds during migration. According to another, the lotus was brought to the delta by nomadic Kalmyks, according to whose beliefs the lotus is a sacred plant. And according to the third, the lotus has always grown in the Volga delta since time immemorial. The floating leaves of the nut-bearing lotus reach 80 cm in diameter and can support a small child, almost like the famous tropical victoria regia.
■ The squeaky gecko, a lizard only 4.1 cm long, lives in the vicinity of Mount Bolshoye Bogdo.
■ Fish living in the Volga delta can reach gigantic sizes. In 1926, a beluga 424 cm long, weighing about 1 ton, 75 years old, was caught. In 2003, at the competition "Catch a fish for history", organized by the Astrakhan State Historical and Architectural Museum-Reserve, a catfish 2.5 m long and weighing 93 kg was presented.
■ The Caspian lowland is characterized by strong winds up to 1220 m/s and more. In June 1985, a tornado passed in the village of Tambovka with a wind speed of over 40 m/s.
■ In Astrakhan, watermelons have been grown since the 7th century. Translated from the Turkic watermelon (harbyuz) - "big cucumber". This fruit was eaten not only raw: for the winter, watermelons were pickled and boiled with pepper. In 2007, a variety of watermelon Lunny was created here - with lemon-yellow pulp. At the end of August, the city hosts the Russian Watermelon festival and a competition for the largest watermelon, as well as a competition for the title of the fastest watermelon eater.

Caspian lowland occupies the northern coast of the Caspian Sea, and is a flat plain with an inclination to the sea, among which mountains rise up to 150 meters high.

The lowland is represented by steppe, semi-desert and desert landscapes, which are of scientific and environmental value. The unique water body of the Caspian Sea is the largest salt lake in Europe, Baskunchak, taken under protection in the Bogdinsko-Baskunchak Reserve.

In the west, the Caspian lowland is crossed by the Volga.

The Volga Delta is the largest and most environmentally friendly in Europe. It begins to the north of Astrakhan, where a large branch, the Buzan, separates. Throughout the entire journey from Astrakhan to the rumbles of the Caspian Sea, the delta is extremely diverse, the main branches 300 - 600 meters wide branch into numerous channels and eriki - small watercourses up to 30 meters wide. At the confluence with the Caspian, the Volga has about 800 mouths.

About 500 plant species belonging to 82 families have been identified on the territory of the Volga delta. The richest among these families are the genera of wormwood, pondweed, astragalus, sedge, milkweed and salt.

About 260 species of birds can be found within the Astrakhan region. Some, settled, can be found all year round, others - migratory and nomadic, during migrations. The conditions for birdwatching are especially favorable in the Astrakhan Nature Reserve, where you can go to watch the spring and autumn bird migrations.

Caspian lowland located on the East European Plain in Russia and Kazakhstan, surrounds the northern part of the Caspian Sea.

The Caspian lowland is surrounded in the north by the Common Syrt, in the west by the Volga Upland and Ergeni, in the east by the Cis-Ural Plateau and Ustyurt. The area of ​​the lowland is about 200 thousand km². The height above sea level is up to 100 m, the southern part of the lowland lies below sea level (up to −28 m). The northwestern part of the lowland between the Ergeninsky Upland, the Kumo-Manych Depression and the Volga is called the Black Lands.

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 Ural, Volga, Terek, Kuma and other rivers. Small rivers (Big and Small Uzen, Wil, Sagiz) dry up in summer or break up into a series of basins, forming lake overflows - Kamysh-Samarsky lakes, Sarpinsky lakes. There are many salt lakes (Baskunchak, Elton, etc.).

Geological structure

The Caspian lowland includes several large tectonic structures (the Caspian syneclise, the Ergenin uplift, the Nogai and Terek depressions). In the Quaternary, 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.

Climate and vegetation

The climate is sharply continental. Average temperatures in January are from -14° in the north to -8° on the coast, in July - from +22° in the north to +24°C in the south. west, evaporation - about 1000 mm. Dry winds are frequent.

Soils and vegetation of the Caspian lowland are characterized by great complexity. Often there are solonetzes, solonchaks.

In the north - sagebrush-cereal steppes on light chestnut soils, in the south - semi-deserts and deserts on brown and sandy soils with a predominance of sagebrush.

Economic importance

Used as pasture.

In the Volga-Akhtuba floodplain, melon growing, horticulture, and vegetable growing are common.

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

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 the Ergeni, in the north by the slopes of the Common Syrt. In the east, the border coincides with the Cis-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 Volgograd, Saratov, Astrakhan and Kalmyk Autonomous Soviet Socialist Republics.

The Caspian lowland is located within a deep tectonic basin - the Caspian syneclise, laid down 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 overlain by Paleozoic and Meso-Cenozoic deposits. Within the lowland, Permian deposits of Kungur age are developed from ancient rocks, at the base of which are stocks of rock salt. Triassic deposits overlie the Permian rocks. 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 lowlands and the penetration of the seas into its territory. The most extensive was the Akchagyl basin, which occupied almost the entire territory of the modern Caspian, the Caspian lowland and penetrated to the north. The long arm of this basin also went towards the Black Sea. In the north, the deposits 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 the 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 rocks of marine and continental origin with a thickness of more than 30 m. Marine sediments consist of clayey, sandy-clayey and sandy strata with marine fauna left by the Baku, Khazar, Lower and Upper Khvalynian 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 by loams. The southern part was subjected to the Upper Khvalynian transgression. The consequence of the Upper Khvalynian transgression are sands and sandy loams of Upper Khvalynian age. The boundary between the two indicated transgressions runs approximately along the zero horizontal.

Many researchers synchronize the Caspian transgressions with the epochs of glaciation of the Russian Plain, but due to insufficient data, the synchronization scheme has not yet been 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 the horizontally lying layers of Permian, Mesozoic and Tertiary rocks are crumpled in many places into small brachianticlinal folds, which are based on a gypsum and salt core.

Due to tangential pressure, salt masses were squeezed out of the original deposit upwards and broke through the overlying rocks, forming domes. In view of the redistribution of salt masses, new places of their concentration were created. Salt domes are hills with a height of 100-150 m, in which gypsum and salts come to the surface (M. Bogdo, B. Bogdo, Bis-Chokho, Chapchagi, etc.). They are associated with the existence of self-sustaining lakes - Elton, Baskunchak, etc., which are fed by saline solutions coming from salt domes. In the Emba region, oil fields are also associated with domes composed of Jurassic and Lower Cretaceous rocks.

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

The northern part of the Caspian lowland is characterized by plain flat surfaces, the relative heights of which do not exceed 1.0-1.5 m. Marine flat plains are disturbed by depressions and numerous tubercles - marmots. Depressions are depressions with a depth of 0.3 to 2.0 m and diameters from 10 to 100 m. Their shape is usually round or oval. They stand out on the surface of the lowlands not so much in depth as in 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. Hollows sometimes stretch for tens of kilometers, in several rows. They begin in the northern part of the lowlands and end in estuaries, not 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 the Ergeni, and then splits into branches. The hollow is covered with a thin layer of alluvium; in the Ergenei region, it is currently filled with alluvium beams, which divides the hollow into separate depressions - lakes. The formation of hollows is associated with the currents 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 separated from it, and its further existence was due to temporary flows from Ergeni. In addition to the landforms described above, coastal landforms have been preserved within the lowlands: 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 sands, the eolian relief prevails here. Between the Volga and Ergeny, as well as to the east on the Volga-Ural watershed, there are massifs of blown sands - Astrakhan and Ryn-Sands. Here the sands form in some places dunes 5-6 m, and sometimes 15 m, mounds, ridges and depressions. 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 slopes facing the prevailing winds are steep on the windward side and gently sloping on the leeward side. Sand blown out of 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. Embas to the mouth of the river. Kuma, there are hillocks, elongated almost in the latitudinal direction, the so-called Baer hillocks. Their height - 7 - 10 m, width - 200-300 m and length - from 0.5 to 8 km. The width of inter-ridge depressions reaches 400-500 m. During the floods of the Volga, they are filled with water. The city of Astrakhan and all the villages within the Volga delta are built on these mounds.

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

Salt domes, the Volga-Akhtuba and Ural valleys add variety to the relief of the lowlands. The Volga Valley is a blooming oasis against the backdrop of a semi-desert. The islands in the floodplain are green with groves of black poplars, silvery poplars, and willows. The Volga valley within the lowland is incised by 20-30 m in the Lower and Upper Khvalynsk marine sediments, which serve as a bedrock coast. The right bank is steep, sheer, strongly washed away by the river. The left root bank is at a great distance from the riverbed. In the left bank, a floodplain terrace (Volga-Akhtubinskaya) is well developed, which extends for tens of kilometers.

The hydrographic network of the lowlands is poor; three large transit rivers flow within its boundaries: the Volga, the Urals and the Terek, devoid of tributaries within the lowlands. Rivers drain only narrow, immediately adjacent coastal strips. In addition to these rivers, there are several small rivers - Big and Small Uzen, Uil, Sagiz, Kushum, which dry up or break up into separate

closed, more or less significant basins of stagnant water, forming lake overflows. An example is the Sarpinsky lakes, into which the waters flowing from the Ergeni are collected, in the central part - the Kamysh-Samarsky lakes, which receive the waters of the Big and Small Uzen, and others. The waters of the river. Kuma in dry years do not reach the Caspian Sea, and the waters of the river. Embas reach it only in high water. In the summer in the river Embe, as in all small rivers of the semi-desert, the water is brackish. Within the lowlands there are a lot of small and large saline 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 in comparison with other regions of the Russian Plain. This is due to the remoteness from the Atlantic Ocean, with the predominance of continental air masses and with increased insolation.

In winter, the distribution of the spurs of the Siberian anticyclone and the associated cold easterly winds, the frequency of which reaches 50%, play a significant role in the formation of weather conditions. The temperatures of the winter months in the Caspian region are unusually low for this latitude (from -14 in the north to -8 ° on the coast of the Caspian Sea). The same temperature conditions are observed in Arkhangelsk and Leningrad in winter. 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. The 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 the beginning of May, the temperature rises rapidly due to the intensification of 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 number as in the Crimea. The isotherms of the summer months are located in the latitudinal direction: in the northern part of the Caspian Sea, the average July temperature is about +22°, in the southern part +23, +24°. The absolute maximum temperature is above +40°.

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

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

The Caspian lowland lies in the semi-desert zone, and it is characterized by light chestnut solonetsous soils, the absorbing 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 unevenly distributed over 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 solonetsous 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 in a wide strip along the shores of the Caspian Sea. Sands are widespread in the Astrakhan Trans-Volga region. A significant part of these sand massifs belongs to the category of moving ones.

In the north of the Caspian lowland, vegetation is represented by wormwood-cereal type; as you move south, the amount of cereals decreases and wormwood begins to predominate. Saltworts predominate in the south. The grass cover here is very sparse, the vegetation is stunted, due to which it suffers less from evaporation: the plants have a very well-developed root system, which allows them to intensively use soil moisture. On slightly saline loams, the following are predominant: 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). Lots of tulips in spring( Tulipa schrenkii), buttercup ( Ranunculus polyrhisus), bluegrass (Roa bulbosa var vivipara). On salt licks, in addition to black wormwood, biyurgun hodgepodge grows ( Anabasis salsa) and lichens ( Aspicilia); in rainy seasons, colonies of algae appear on solonetzes, having the appearance of black, hair-like, threads more than 30 long pressed to the ground.cm.

Various saltworts, black wormwood and shrubs grow on salt marshes: tamarisk ( Tamarix romosissima), kermek ( Statice suffruticosa). The kiyak grass grows on the sands( Elymus giganteus), which is a sand binder. In wet basins among the sands there are willows( Salix rosmarinifolia), goof ( Elaeagnus angustifolia) and other shrubs. In depressions, among hilly sands, where fresh groundwater lies very close to the surface, white poplar grows.( Populus alba), speck (Ro pulus nigra), aspen, willow ( Salix rosmarinifaboutla), rose hip ( Rosa cinnamomea). In the floodplain of the Volga there are: oak( Quercus robur), elm ( Ulmuslaevis), speck.

Characteristic representatives of animals are: sandy gopher, or yellow( 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), ubiquitous corsac fox( Vulpes corsak).

Of the birds found: black lark( Melanocorypha yeltonieusis) and small ( Calandrella). Floodplains and river deltas, especially the Volga, abound in birds. The Volga Delta is characterized by: great cormorant( Phalacrocorax carbo), white-tailed eagle( Haliaetus albicilla), grey goose (apse rapseg), white heron ( Egretta alba), sultan chicken( Porphyrio polioephalus), pheasant ( Phasianus colchicus), whiskered tit ( Ponurus biarmicus).

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

In the Volga-Akhtuba floodplain, melon growing, horticulture and horticulture, industrial crops and rice are flourishing.

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

The Emba oil field is being developed, table salt is being mined (Lakes Baskunchak, Elton).

- Source-

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

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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. From the north it is limited by the Common Syrt, from the west by the Volga Upland, and from the east by the Cis-Ural Plateau and Ustyurt. The occupied area is about 200 thousand square meters. km and has a slope to the sea.

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

• Volga,
• Ural,
• Terek,
• Kuma.

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

Remark 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 starts north of Astrakhan. Its main branches are 300-600 m wide, branching into numerous channels and eriki, which are small, up to 30 m wide, watercourses. 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 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 lowland, precipitation is no more than 150-200 mm. To the northwest, their number increases to 350 mm. Evaporates more 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 grass-fescue steppe, to the wormwood-cereal semi-desert in the south. Meadow vegetation covers large estuaries and is represented by thickets of couch grass. Vegetation cover is thinning out in desert areas.

The vegetation cover of the lowlands is used for pastures for livestock. Melon growing, horticulture, and vegetable growing are practiced in the Volga-Akhtuba floodplain.

Salt is mined in salt lakes. The Ural-Embinsky oil and gas region is located on the territory of the Caspian lowland and oil and gas are being produced.

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 inhabited by 56 species of mammals, 278 species of birds, 18 species of amphibians and reptiles. A number of species belong to the category of rare and endangered. The Caspian coast is of great importance for migratory and wintering birds. According to experts, about 1.5 million waterfowl winter in the southern Caspian.

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

In this area, 20 thousand pairs of gulls and terns, up to 1 thousand pairs of pink pelicans arranged their nests.

Remark 2

In the Volga-Ural interfluve, the main population of commercial ungulate mammals is concentrated - the saiga, whose population numbers up to 300 heads. At the beginning of 2009, the Service for Nature Management and Environmental Protection 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 period of the same year, 1.5 thousand saigas entered from the territory of Kazakhstan. This indicates their spontaneous movement from one territory to another, which greatly complicates the conduct of full-fledged monitoring and protection.

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

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

More than 30 species are common for the region, the remaining species are found in the deserts of the Caspian Sea.

Endemics include the long-spine hedgehog - a rare species of insectivore, weighing up to 750 g and leading a nocturnal lifestyle, the Ustyurt mountain sheep of the family of bovids of the artiodactyl order, the honey badger - the only species in the mustelid family, the Caspian seal - an inhabitant of the entire water area of ​​the Caspian Sea, but in the cold season concentrated on the northern coast of the Caspian Sea, Bobrinsky's leather bat is a bat of the order of bats. These animal species are endangered.

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

Environmental problems of the territory

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

The territory of the Republic of Kalmykia is overloaded with grazing lands, where unsystematic grazing is carried out. The result is their desertification, the herbage is knocked out. In order to prevent desertification of the Kalmyk lands, the “Federal Program to Combat Desertification of the Territory” is in force. There are first positive results in resolving this issue.

Another acute problem is water pollution in the Volga. Flowing through the entire Russian Plain and, taking untreated waters of enterprises along its entire length, the river carries them into the Caspian Sea, creating an unfavorable ecological situation in this area. As a result of pollution of the Caspian Sea, its biodiversity is reduced, foreign bacteria penetrate, and pollution from land sources occurs.

Remark 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 can be called the mass reproduction of the comb jelly Mnemiopsis. Appearing for the first time in the Sea of ​​Azov, he literally devastated it, and penetration into the Caspian Sea was not difficult. Feeding on zooplankton, comb jelly destroys the food base of Caspian fish. Having no natural enemies, rapidly multiplying, it became out of competition with other plankton consumers.

Oil pollution adversely affects the 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 zander is declining.

The construction of hydroelectric power plants on rivers also leads to undesirable consequences - fish are deprived of their natural habitats, the riverbed begins to silt. Fortunately, a protected area has been created in the northern Caspian and an appropriate regime has been introduced, which provides for the prohibition of any geophysical work.

Remark 4

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