Tectonic structure of the East European Plain. Relief of the East European Plain

The East European Plain is part of the East European Platform. This is an ancient and stable block, bordering with folded belts. In the east, the platform is framed by the Urals. The tectonic structure of the East European Plain is such that in the south it adjoins the Mediterranean folded belt and the Scythian plate, which occupies the area of Ciscaucasia and Crimea. The border with it runs from the mouth of the Danube, along the Black and Azov seas.

Tectonics

The complex tectonic structure of the East European Plain has been studied by many scientists. Foreign experts call it Russian (just like a platform). Part of its southern border passes through the Tsimlyansk reservoir region . There is a large geological anomaly here - the Main East European fault. The structure of the platform on this site is very complex, as it wedges into the Scythian plate.

Because of the colossal area, the tectonic structure of the East European Plain is uneven. Scientists distinguish two large shield-protrusions (Ukrainian and Baltic), as well as several areas of shallow and deep bedding of the foundation. It is composed of Archean, Lower Proterozoic and deep-metamorphosed formations.

Archean layers

The multi-tiered tectonic structure of the East European Plain is such that the foundation is exposed in the area of the Baltic Shield in Karelia and on the Kola Peninsula. The same can be traced to the Archean layer in the Konotop, Podolsky and Pridneprovsky massifs. Here it is represented by amphibolites, migmatites and gneisses. In these rocks, there are many clusters of ferruginous quartzites and graphite. Their age is about 3 million years.

Another example of the Archaean stratum is the Voronezh anteclise, where the foundation is laid not very deep. It consists of volcanic and feminine formations. These rocks are distinguished by a large number of intrusions of acidic and basic composition, the age of which is about 2.7 million years.

Lowering and lifting

In general, the territory of the East European Plain is a platform cover, which is composed of deposits of the Proterozoic, Paleozoic, Mesozoic and Cenozoic eras. The foundation of the Russian plate is distinguished by the uneven relief of the foundation roof. In its structure, four main zones of descents and uplifts are distinguished. They alternately alternate with each other. This is the Caspian depression zone, the Sarmatian uplift zone, the Baltic-Central Russian lowland zone and the Baltic zone of uplifts.

The average capacity of the platform is from 35 to 40 kilometers (the maximum power recorded in the Voronezh anteclise is 55 kilometers, where there is a thickened basalt layer). The minimum figures relate to the Caspian syneclise. The rise of the basalt layer led to the thinning of the earth's crust in the Pachelmsky avlakogen.

The Caspian Massif

The approximate age of the East European Plain is 1.6-2.6 million years (its oldest sites are located in the eastern part). To the ancient massifs can be attributed to the Tatarsky, the Caspian and Zhigulyovsko-Pugachevsky. They share a prototypical cover. The largest massif is the Caspian. Wells are present in the Samara Trans-Volga and Saratov Volga regions. High-alumina Archaean gneisses and shales have been discovered in them.

The Caspian massif, due to which the height of the East European Plain is determined on its southeastern borders, is distinguished by a specific deep structure. In its center there is no granite layer, but there is a rise in basalt in the Aralsor and Hobdin gravity maxima. Another picture is formed on the outskirts of the massif. There is a thin layer of granite.

The Caspian syneclise includes many salt domes. On its western and northern sides there are deep faults (the Volgograd step, the Zhadovsky ledge, the Tokarev flexure). The foundation here is lowered to a depth of 25 kilometers. Salt domes are most developed in the Guriev zone. Their size can be hundreds of square kilometers. They have a triangular, round and even elliptical shape. The largest salt domes - Chelkarsky, Dossor, Inder, Makat, Elton and Saharno-Lebyazhinsky.

Syneclise and anteclise

Moscow syneclise is the largest on the Russian platform. This is in its central part of the East European Plain. Photos and studies of geologists show that on its northern side there are two uplifts (Soligalichskoe and Sukhonskoye). The most descended part of the syneclise is located not far from Syktyvkar, where several salt domes (Seregovsky domes), composed of Devonian salt, are traced. Its basis is the Central Russian aulacogene, which is filled with sediments.

Another important tectonic element of the plain is the Volga-Ural Antekliza. It consists of large basins and uplifts. Antekliza is a complex structure. Its main uplift is the Tokmov arch in Mordovia. The key water artery of the region - the Volga flows through the anteclise. Other large rivers of the East European Plain (Don, Dnieper, Western Dvina) are inferior to it in the area of the basin and other characteristics.

Relief

The average height of the East European Plain is 170 meters. The highest indicator was recorded on the Preduralal Upland in Tatarstan (479 meters). In general, the relief of the plain varies depending on the region. Its central part is divided into several alternating lowlands and hills. The first of them is located in the valley of the Oka, to the north of the Donetsk ridge. This is the Central Russian Upland. During the Dnieper glaciation, it was covered with a glacier. This is evidenced by characteristic sediments, including moraine on the right bank of the Oka River, not far from Serpukhov.

In the Urals there is the Bugulmino-Belebeevskaya Upland. It is a hilly and straggly plateau. It is composed of siltstones, limestones, clays, marls and sandstones. There are many karst dips and caves. The erosion relief is dissected by rivers - tributaries of the Volga, Kama and Belaya. The hill is rich in oil fields (Romashkinskoye, Tuimazinskoye, Shkapovskoye). Gentle slopes are weathered less than the tops of the syrt.

The Volga Upland

On the right bank of the Volga, the Volga Upland begins. It stretches from Volgograd to Nizhny Novgorod, and in the west neighbors with the Tambov Lowland. The relief of the East European Plain in this part of it was formed as a result of the destruction of rocks, after which clays, sands, chalk, marl and gum formed here. All these deposits belong to the Paleogene, Jurassic and Cretaceous.

The more ancient and hard Permian and Carboniferous limestones come to the surface on the banks of the Samara Luke. Among the deposits, strong sandstones should also be distinguished. The crystalline basement of the Volga Upland is lowered to a great depth (about 800 meters).

The closer to the Oka-Don lowland, the more the surface decreases. The Volga slopes are precipitous and are dissected by numerous ravines and gullies. Because of this, a highly rugged terrain was formed here.

Common Syrt and Oka-Don lowlands

The common Syrt is another important component of the relief, which is distinguished by the East European Plain. Photos of this region on the border of Russia and Kazakhstan show the region of chernozem, chestnut soils and solonchaks prevailing at the watersheds and river valleys. The common Syrt begins in the Trans-Volga region and extends 500 kilometers in an easterly direction. It is mainly located in the interfluve between the Big Irgiz and the Lesser Irgiz, in the east it adjoins the Southern Urals.

Between the Volga and Central Russian Uplands is the Oka-Don lowland. Its northern part is also known as Meshchera. The northern border of the lowlands is the Oka. In the south, its natural boundary is the Kalach Upland. An important part of the lowland is the Oka-Zninsky shaft. It stretches through Morshansk, Kasimov and Kovrov. In the north, the surface of the Oka-Don lowland was formed from glacial deposits, and in the south its base is sand.

Valdai and Northern Uvaly

A huge East-European plain lies between the Atlantic and Arctic Oceans. The basins of rivers flowing into them begin at the Valdai Upland. Its highest point is 346 meters. Valdai is located in the Smolensk, Tver and Novgorod regions. It differs hilly, ridge and moraine relief. There are many marshes and lakes here (including Seliger and Verkhnevolzhskie lakes).

The northernmost part of the East European Plain is the Northern Uval. They occupy the territory of the Republic of Komi, Kostroma, Kirov and Vologda regions. The hill consisted of a gradual decline in the northern direction, until it rested on the White and Barents Seas. Its maximum height is 293 meters. Northern Uvaly - watershed of the Northern Dvina and Volga basin.

Black Sea lowland

In the south-west, the East European Plain ends with the Black Sea Lowland located on the territory of Ukraine and Moldova. On the one hand, it is bounded by the Danube delta, and on the other by the Azov river Kalminus. The Black Sea lowland consists of Neogene and Paleogene deposits (clays, sands and limestones). They are covered with loams and loess.

The lowland is crossed by the valleys of several rivers: the Dniester, the Southern Bug and the Dnieper. Their banks are characterized by steep and frequent landslides. On the coast there are many estuaries (Dniester, Dnieper, etc.). Another recognizable feature is the abundance of sandy braids. In the Black Sea lowland dominated by a steppe landscape with dark chestnut and chernozem soils. This is the richest agricultural granary.