Tectonic lakes: examples, list. The largest glacial-tectonic lakes

The lake is an element of the hydrosphere. It is a reservoir that has arisen naturally or artificially. It is filled within its bed with water and has no direct connection with the sea or the ocean. There are about 5 million such reservoirs in the world.

general characteristics

In terms of planetology, the lake is an existent in space and time, an object filled with a substance that is in a liquid state. In the geographical sense it is represented as a closed deepening of the land into which water enters and where water accumulates. The chemical composition of the lakes remains constant for a relatively long time. The substance filling it is updated, but much less frequently than in the river. In this case, the currents present in it do not act as the predominant factor determining the regime. Lakes provide regulation of river flow. In the water pass chemical reactions. In the course of interactions, some elements settle in bottom sediments, others pass into water. In some water bodies, which usually do not have a runoff, the content of salts increases due to evaporation. As a result of this process, there is a significant change in the salt and mineral composition of the lakes. Due to the large thermal inertia, large objects soften the climatic conditions of the adjacent zones, reducing seasonal and annual meteorological fluctuations.

Bottom sediments

When they accumulate, there are significant changes in the relief, the size of the lake basins. When the reservoirs are overgrown, new forms are formed-plain and convex. Lakes often form barriers to groundwater. This, in turn, causes bogging of nearby land sites. In the lakes there is a continuous accumulation of mineral and organic elements. As a result, powerful deposits of sediments are formed. They change in the course of further development of water bodies and their transformation into land or marsh. Under certain conditions, bottom sediments are converted into mountain fossils of organic origin.

Features of education

Reservoirs occur for a variety of reasons. Their natural creators are the wind, water, tectonic forces. On the surface of the earth, the basins can be washed out with water. Due to the action of the wind, a depression is formed. The glacier grinds the hollow, and the mountain collapse stems the river valley. So it turns out a bed for the future pond. After filling with water, a lake appears. In geography, water bodies are classified according to the mode of formation, the presence of life, the concentration of salts. Only in the salt lakes there are no living organisms. Most of the reservoirs are created due to displacements of the earth's crust or volcanic eruptions.

Classification

According to their origin, water bodies are divided into:

1. Tectonic lakes. They are formed due to the filling of cracks in the water. Thus, the Caspian Sea, the largest lake in Russia and the whole planet, was formed by displacements. Prior to the uplift of the Caucasian Range, the Caspian Sea was associated with the Black Sea. Another example of a large-scale fault is the East African rift structure. It extends from the south-eastern region of the continent to the north to south-west Asia. Here lies a chain of tectonic lakes. The most famous are the lake. Albert, Tanganyika, Edward, Nyasa (Malawi). To the same system is the Dead Sea. It is considered the lowest situated tectonic lake in the world.
2. River water bodies.
3. Primorskie lakes (estuaries, lagoons). The most famous is the Venetian lagoon. It is located in the northern region of the Adriatic Sea.
4. The failure of the lake. As one of the features of some of these reservoirs is their periodic occurrence and disappearance. This phenomenon depends on the specific dynamics of groundwater. A typical example of a karst lake is Lake. Ertsov, located in the South. Ossetia.
5. Mountain water reservoirs. They are located in the ridge basins.
6. Glacial lakes. They are formed when the ice thickness is shifted.
7. The pond lake. Such reservoirs are formed during the collapse of the mountain part. An example of such a lake is Lake. Ritsa, located in Abkhazia.

Volcanic water reservoirs

Such lakes are located in extinct craters and explosion tubes. Such water bodies are found in Europe. For example, volcanic lakes are present in the Eifel region (in Germany). Near them, there is a weak manifestation of volcanic activity in the form of hot springs. As the most common type of such lakes is a crater filled with water. Oz. Crai-ter of the volcano Mazama in Oregon was formed more than 6.5 thousand years ago. Its diameter is 10 km, and the depth is 589 m. Some lakes are formed during the blocking by lava flows of volcanic valleys. Gradually, they accumulate water and form a pond. So, for example, there was a lake. Kivu is the depression of the East African rift structure, located on the border of Rwanda and Zaire. Leaving once from the lake. Tanganyika r. Ruzizi flowed along the Kivu valley to the north, towards the Nile. But from the moment, after the eruption of the nearby volcano, the channel was blocked, it filled the hollow.

Other types

Lakes can form in the voids of limestone. Water dissolves this rock, forming huge caves. Such lakes can occur in areas of underground salt deposits. Lakes can be artificial. They are intended, as a rule, to store water for different purposes. Often, the creation of artificial lakes is associated with the carrying out of various earthworks. However, in some cases, their appearance is an incidental consequence of them. So, for example, artificial reservoirs are formed in the developed quarries. Among the largest lakes worth noting the lake. Nasser, located on the border of Sudan and Egypt. It was formed by damming the valley of the river. Nile. Another example of a large artificial lake is the lake. Mead. It appeared after the installation of the dam on the river. Colorado. As a rule, such lakes serve local HPPs, provide nearby settlements and industrial zones with water.

The largest glacial-tectonic lakes

The movement of the earth's crust is one of the main reasons for the formation of water bodies. Due to this displacement in a number of cases, glaciers are slipping. Reservoirs are very common in the plains and in the mountains. They can be found both in the basins and between the hills in the depressions. Glacial-tectonic lakes (examples: Ladoga, Onega) are quite common in the Northern Hemisphere. Avalanches left deep enough depressions after themselves. They accumulated melt water. Deposits (moraine) dammed the depressions. So water bodies were formed in the Lake District. At the foot of the town of Bolshoy Arber there is a lake. Arbersee. This reservoir remained after the ice age.

Tectonic lakes: examples, characteristics

Such reservoirs are formed in the areas of shear and fracture of the cortex. Usually, the tectonic lakes of the world are deep and narrow. They differ in sheer straight-line shores. These ponds are mainly in through deep gorges. The tectonic lakes of Russia (examples: Kuril and Dalnee in Kamchatka) are characterized by a low-lying bottom (below the oceanic level). So, the lake. Kurilskoye is located in the southern part of Kamchatka, in a picturesque deep basin. The area is surrounded by mountains. The maximum depth of the reservoir is 360 m. It has steep banks, from which a multitude of mountain streams flow. From the reservoir flows p. The lake. Hot springs come to the surface along the coast. In the center of the lake there is a small elevation - an islet. He is called "heart-stone." Not far from the lake are unique pumice deposits. They are called Kutkhin bata. Today Lake. Kurilskoye is a zakaznik and declared a zoological natural monument.

Bottom profile

The glacial-tectonic lakes of the world have a sharply outlined relief. It is represented in the form of a broken curve. Glacial deposits and accumulative processes in sediments can not have a significant effect on the clarity of the hollow lines. However, in some cases, the effect can be quite noticeable. Glacier-tectonic lakes can have a bottom covered with "scars", "ram's foreheads". They are fairly well seen on islands and rocky shores. The latter consist mainly of hard stone rocks. They are weakly susceptible to erosion, which, in turn, causes a small rate of accumulation of precipitation. Such tectonic lakes of Russia are classified as a = 2-4 and a = 4-10. The deep-sea zone (over 10 m) of the total volume is 60-70%, shallow (up to 5 m) - 15-20%. The tectonic lakes are distinguished by the heterogeneity of water according to thermal indices. During the maximum warming of the surface, the low temperature of the bottom waters is maintained. This is due to stable thermal stratifications. Vegetation is rare. It can be found along the shores in closed bays.

Spread

Where, besides Kamchatka, are there tectonic lakes? List of the most famous reservoirs of the country includes such entities as:

1. Sandalwood.
2. Sundozero.
3. Pallier.
4. Randozero.
5. Salvilambi.

These reservoirs are located in the basin of the Suna River. In the forest-steppe Zauralye also there are tectonic lakes. Examples of water bodies:

1. Welgi.
2. Argayash.
3. Shablish.
4. Tishki.
5. Sugoyak.
6. Calda.
7. B. Kuyash and others.

The depth of water bodies in the Trans-Ural plain does not exceed 8-10 m. They are related to erosion-tectonic lakes by origin. Their cavities were modified, respectively, under the influence of erosion processes. Many reservoirs in the Trans-Urals are confined to ancient river valleys. This, in particular, such tectonic lakes as Kamishnoe, Alakul, Peschanoe, Etkul and others.

The unique pond

In the southern part of Eastern Siberia lies Lake. Baikal is a tectonic lake. Its length is more than 630 km., And the length of the coastline is 2100 km. The width of the reservoir varies from 25 to 79 km. The total area of the lake is 31.5 square kilometers. Km. This pond is considered the deepest on the planet. It contains the largest volume of fresh water on Earth (23 thousand m ³ ). This is 1/10 of the world stock. Complete renewal of water in the reservoir occurs over 332 years. Its age is about 15-20 million liters. Baikal is considered one of the oldest lakes.

Terrain

Baikal lies in a deep depression. It is surrounded by mountain ranges covered with taiga. The terrain near the reservoir is characterized by a complex, deeply dissected relief. Not far from the lake there is a noticeable expansion of the mountain strip. The ridges run parallel to each other in the direction from the northwest to the southeast. They are separated by hollow-like depressions. River valleys along their bottom, in some places small tectonic lakes are formed. Displacements of the earth's crust take place in this region today. This is indicated by relatively frequent earthquakes near the basin, exits to the surface of hot springs, as well as the lowering of large areas of the coast. The water in the lake is blue-green. It is distinguished by its exceptional transparency and purity. In some places, it is possible to clearly see stones lying at a depth of 10-15 m, thickets of algae. The white disk, lowered into the water, is visible even at a depth of 40 m.

Distinctive features

The shape of the lake is a born crescent. The reservoir stretched between 55 ° 47 'and 51 ° 28' sow. Latitude and 103 ° 43 'and 109 ° 58' east. Longitude. The maximum width in the center is 81 km, the minimum (opposite the delta of the Selenga River) is 27 km. The lake is located above the sea level at an altitude of 455 m. 336 rivers and streams flow into the reservoir. Half of the water enters it from the river. The Selenga. Leaves from the lake one river - Angara. It should be noted, however, that in the scientific community there are still discussions on the exact number of flows flowing into the body of water. Most scientists agree that there are fewer than 336.

Water

The liquid substance that fills the lake is considered unique in nature. As was said above, the water is surprisingly clear and pure, rich in oxygen. In the recent past, it was even considered curative. Baikal's water was treated for various diseases. In the spring, its transparency is higher. According to the indicators, it is approaching the standard - the Sargasso Sea. In it, the transparency of water is estimated at 65 m. During the period of mass flowering of algae, the lake's index decreases. Nevertheless, even at this time in the calm from the boat you can see the bottom at a fairly decent depth. High transparency is caused by the activity of living organisms. Thanks to them, the lake is slightly mineralized. The water is approximate in structure to distilled water. Importance of the lake. Baikal can not be overestimated. In this regard, the state provides special environmental protection for this area.