Lakes of tectonic origin always have great depth. Glacial lakes of Russia. Tectonic lakes: examples, characteristics

The science of limonology deals with the study of lakes. Scientists distinguish several types by origin, among which there are tectonic lakes. They are formed as a result of the movement of lithospheric plates and the appearance of depressions in the earth's crust. This is how the deepest lake in the world - Baikal and the largest in area - the Caspian Sea were formed. In the East African rift system, a large rift has formed, where a number of lakes are concentrated:

Tanganyika;
Albert;
Nyasa;
Edward;
Dead Sea (is the lowest lake on the planet).

By their form, tectonic lakes are very narrow and deep bodies of water, with distinct shores. Their bottom is usually located below ocean level. It has a clear outline that resembles a curved, broken, curved line. At the bottom, you can find traces of various forms of relief. The shores of tectonic lakes are composed of hard rocks, and they are poorly eroded. On average, the deep-water zone of lakes of this type is up to 70%, and shallow water - no more than 20%. The water of tectonic lakes is not the same, but generally has a low temperature.

The largest tectonic lakes in the world

The Suna River basin has both large and medium tectonic lakes:

Randozero;
Palier;
Salvilambi;
Sandal;
Sundozero.

Among the lakes tectonic origin Kyrgyzstan should be named Son-Kul, Chatyr-Kul and Issyk-Kul. On the territory of the Trans-Ural plain there are also several lakes formed as a result of a tectonic fault in the solid shell of the earth. These are Argayash and Kaldy, Uelgi and Tishki, Shablish and Sugoyak. In Asia, there are also tectonic lakes Kukunor, Khubsugul, Urmia, Biwa and Van.

There are also a number of lakes of tectonic origin in Europe. These are Geneva and Veettern, Como and Constance, Balaton and Lake Maggiore. Among the American lakes of tectonic origin, the Great North American Lakes should be mentioned. Winnipeg, Athabasca and Big Bear Lake are of the same type.

Tectonic lakes are located on plains or in the area of \u200b\u200bintermontane troughs. They are of considerable depth and enormous size. Not only folds of the lithosphere, but also ruptures of the earth's crust take part in the formation of lake depressions. The bottom of tectonic lakes is below ocean level. Such reservoirs are found on all continents of the earth, but their greatest number is located precisely in the fault zone of the earth's crust.

The uniqueness of natural lakes lies in a number of their special characteristics. They are characterized by a slowed down water exchange, free thermal regime, a peculiar chemical composition, drops in the water level.

In addition, they create their own microclimate and cause changes in the adjacent landscape. They accumulate mineral and organic substances, some of which have value and usefulness.

Geographic feature "lake" (meaning)

There are about 5,000,000 lakes in our world. Lakes on the globe occupy almost 2% of the surface, which is almost 2.6 million km 3. As a component of the hydrosphere, the classic natural lakes, are reservoirs of natural origin, which are lake bowls with water that do not have direct contact (contact) with the sea or ocean. There is a whole science that studies them - limnology. However, there are also man-made lakes that have arisen as a result of human activities.

If we consider the lake as geographic feature, then its definition becomes clearer: it is a pit on land with closed edges, into which flowing water falls and as a result accumulates there.

Characteristics of lakes

To give an accurate description of a particular lake, you need to determine its origin, position (above or below ground), type of water balance (waste or not), mineralization parameters (fresh or not), its chemical composition, etc.

In addition, the following parameters must be accurately determined: total area water surface, the total length of the coastline, the maximum distance between opposite banks, the average width of the lake (calculated by dividing the area by the previous indicator), the volume of water that fills it, its average and maximum depth.

Lake types by origin

The generally accepted classification of lakes by origin is as follows:

Anthropogenic (artificial) - created by man;
Natural - arose naturally (exogenous or endogenous - either from within the Earth, or as a result of processes on its surface), without human intervention.

Natural lakes, in turn, have their own division according to the principle of origin:

Tectonic - cracks in the earth's crust that have arisen for one reason or another are filled with water. The most famous lake of this type is Baikal.
Glacial - the glacier melts and the resulting water creates a lake in the hollow of the glacier itself or any other. Such lakes, for example, in Karelia and Finland: lakes appeared along the trajectory of the glacier along tectonic cracks.
Old woman, lagoon or estuary - a decrease in water level cuts off part of the river or ocean.
Karst, suffusion, thermokarst, aeolian - leaching, subsidence, thawing, blowing, respectively, create a depression that is filled with water.
A dam occurs when a landslide or earthquake cuts off a part of the water surface from the main water body by a land bridge.
Water often collects in mountain basins and craters of volcanoes or channels of their eruption.
Other.

The value of lakes in nature and for humans

Lakes are natural reservoirs of water that can regulate river flow: take in excess water and, conversely, give away part of it with a general decrease in the water level in the river. A large body of water has a large thermal inertia, the effect of which can significantly soften the climate of nearby territories.

The lakes are important subject for fishing, organizing salt extraction, laying waterways... Water from lakes is often used for water supply. The reservoirs can be used to organize the energy reservoir of a hydroelectric plant. Sapropels are mined from them. Some lake mud has medicinal properties and are used in medicine. The importance of lakes in the ecosystem of the planet can hardly be overestimated; they are an organic element of the entire natural mechanism.

The largest lakes in the world

Among the lakes, there are two main record holders:

The Caspian Sea is the largest in area (376,000 km 2), but relatively shallow (30 m);

(Lake Baikal)

Baikal is a depth record (1620 meters!).

Tectonic lakes are the average size record holders in the lake community.

Definition 1

In the aspect of planetology, a lake is an object that stably exists in space and time, which is filled with a substance in a liquid form.

In a geographical sense, it can be represented as a closed depression of land, into which water is systematically. For a sufficiently long period of time, the chemical composition of the lakes does not change. The liquid filling it is renewed, but much less frequently than in the river. At the same time, the currents present in it do not act as the main factor through which it is possible to determine the general regime.

Remark 1

Lakes mainly provide balancing of river flow, as complex chemical reactions take place in their waters.

In the process of interactions, some elements pass into a liquid, while others settle in bottom sediments. In some water bodies that do not have such a runoff, the salt content increases significantly due to evaporation. As a result, there is a radical change in the mineral and salt composition of the lakes. Large objects soften climatic conditions territories close to them by means of large-scale thermal inertia, thereby reducing seasonal and annual weather fluctuations.

Tectonic lakes: characteristics, examples

Definition 2

Tectonic lakes are reservoirs that were formed at the sites of faults and shifts in the earth's crust.

Basically, these objects are narrow and deep, and also differ in straight, steep banks. Such lakes are located mainly in deep through gorges. Tectonic lakes of Russia (examples: Dalneye and Kurilsk in Kamchatka) are characterized by a low-lying bottom. So, the Kurilskoye reservoir flows in the southern part of Kamchatka, in a colorful deep basin. This area is completely surrounded by mountains. Maximum depth the lake is about 360 m, and a huge number of mountain streams constantly flow down from the steep shores. From this reservoir flows the Ozernaya river, along the banks of which rather hot springs come to the surface. In the center of the reservoir there is an island in the form of a small dome-shaped elevation, popularly called "heart-stone". Not far from the lake there are unique pumice deposits called Kutkhiny baty. Today Kurilskoye Lake is considered a nature reserve and declared a natural zoological monument.

Interestingly, tectonic lakes are located only in explosion tubes and extinct craters... Such reservoirs are often found in European countries. For example, volcanic lakes are observed in the Eifel region (in Germany), near which a weak manifestation of volcanic activity in the form of hot springs is recorded. A crater filled with water is the most common type of such body of water.

Example 1

For example, Lake Kreyter of the Mazama volcano in Oregon was formed about 6.5 thousand years ago.

Its diameter reaches 10 km, and its depth is more than 589 m. Part of the reservoir was formed by volcanic valleys in the process of blocking by continuous lava flows, in which water accumulates over time and a lake forms. This is how the Kivu reservoir appeared, which is a depression of the East African rift structure, which is located on the border of Zaire and Rwanda. The Ruzizi River, flowing out more than 7 thousand years ago from Tanganyika, flowed along the Kivu valley to the northern regions, towards the Nile. But from that period, the channel was "sealed" in with the eruption of a nearby volcano.

Bottom profile of tectonic lakes

Tectonic water bodies of the world have a clearly outlined bottom relief, presented in the form of a broken curve.

Accumulative processes and glacial deposits in sediments did not have a significant effect on the relief of the lines of the basins, but in a number of special cases the effect can be quite noticeable.

Glacial-tectonic lakes can have a bottom covered with "scars" and "sheep's foreheads", which can be observed on rocky shores and islands. The latter are formed mainly from hard rock, which practically does not lend itself to erosion. As a result of this process, a low rate of precipitation accumulation occurs. Geographers classify similar tectonic reservoirs in Russia as a \u003d 2-4 and a \u003d 4-10. The deep-water surface (over 10 m) of the total volume reaches approximately 60-70%, shallow-water (up to 5 m) - 15-20%. These lakes are characterized by diverse waters in terms of thermal indicators. The low temperature of the bottom waters remains during the period of maximum surface heating. This is due to thermal stable stratifications. Vegetation in these zones is extremely rare, since it can only be found along the shores in closed bays.

Features of the formation of reservoirs

Lakes arise for a variety of reasons. Their natural creators are:

water;
wind;
tectonic forces.

On the earth's surface, basins are often washed out by means of water. Due to the action of the wind, a depression is created, after which the glacier resurfaces the depression, and a rock fall gradually damages the river valley. This is how the bed for the future reservoir is formed.

By origin, the lakes are divided into:

river reservoirs;
seaside lakes;
mountain reservoirs;
glacial lakes;
dammed reservoirs;
tectonic lakes;
failing lakes.

Tectonic lakes appear as a result of water filling small cracks in the crust. Thus, the shifts formed the Caspian Sea - the largest body of water in Russia and the entire planet. Before the rise of the Caucasian ridge, the Caspian Sea was directly connected with the Black Sea. Another striking example of a large-scale fracture of the earth's crust is the East African structure, which extends from the southwestern region of the continent northward to the southeast of Asia. A chain of tectonic reservoirs is located here. The most famous are Tanganyika, Albert Edward, Nyasa. Experts refer to the same system the Dead Sea - the lowest tectonic lake in the world.

Seaside lakes are estuaries and lagoons, which are mainly located in northern regions Adriatic Sea... One of the specific features of failed water bodies is their systematic disappearance and emergence. it a natural phenomenon directly dependent on the unique dynamics of groundwater. Lake Ertsov, located in South Ossetia, is considered an ideal example of this object. Mountain reservoirs are located in ridge basins, and glacial lakes are formed when the thickness of perennial ice moves.

A lake is a body of water with a slowed down water exchange. Lakes are classified according to various criteria: in origin (tectonic, volcanic, dammed, glacial, sinkhole, karst, etc.); by salinity (fresh, brackish, saline, brine, etc.); by trophicity (oligotrophic, mesotrophic, eutrophic, etc.); by position in the landscape (lowland, floodplain, highland, etc.); in depth (shallow, deep, superdeep); by morphology (rounded, elongated, ribbon-like, sickle-shaped, distinct, etc.); by flow (closed, low flow, periodically flow, temporary, relic); by type of use (fishery, for water supply, for the extraction of salt, sapropel ore, therapeutic mud, etc.); by condition (clean, polluted, overgrown, etc.).

How many years do lakes live?

Most often, it is relatively short - several thousand or tens of thousands of years. This applies primarily to glacial and old lakes. Karst, volcanic and especially tectonic lakes can exist for millions and tens of millions of years. For example, one of the lakes in Australia was formed about 700 million years ago.

How many lakes are there on Earth?

The exact calculation has not yet been made. There are probably about 2 million lakes in Canada and Alaska, about 100 thousand in Finland and on the Scandinavian Peninsulas. About 100 thousand in Great Britain and Ireland, as well as Denmark, Belgium, Holland and France. Hydrologists believe that there are about 5 million lakes on the earth.

Tectonic lakes.

They form in places of faults and shifts in the earth's crust. As a rule, these are deep narrow reservoirs with straight-sided steep banks, located in deep through gorges The bottom of such lakes located in Kamchatka is located below ocean level. Tectonic lakes include Dalneye and Kurilsk. Kuril Lake is located in the south of Kamchatka in a deep picturesque basin surrounded by mountains. The maximum depth of the lake is 306 m. Its banks are steep. Numerous mountain streams flow from them. The lake is a waste water, from which the Ozernaya river starts. On the shores of the lake, hot springs come to the surface, and in the middle of it there rises an island called the Heart-stone. Not far from the lake there is a unique outcrop of pumice stones called Kutkhiny baty. Currently, the lake is declared a nature reserve and a zoological natural monument

The bottom profile of tectonic lakes is sharply delineated, looks like a broken curve. Glacial deposits and the processes of sediment accumulation have little changed the clarity of the tectonic lines of the lake basin. The influence of the glacier on the formation of the basin is noticeable; it leaves traces of its presence in the form of scars, sheep's foreheads, which are clearly visible on rocky shores and islands. The shores of the lakes are composed mainly of hard stone rocks, which are poorly eroded, which is one of the reasons for the weak sedimentation process. These lakes belong to the group of lakes of normal depth (a \u003d 2-4) and deep (a \u003d 4-10). The deep-water zone (more than 10 m) of the total volume of the lake is 60-70%, shallow water (0-5m) 15-20%. The waters of the lakes are thermally inhomogeneous: during the period of the greatest heating of surface waters, low bottom temperatures remain, which is facilitated by stable thermal stratification. Aquatic vegetation is rare, only in a narrow strip along the shores of closed bays. Typical lakes in the river basin. The Suna are large and medium-sized: Palje, Sundozero, Sandal, as well as the very small lakes Salvilambi and Randozero, located on the private catchments of the Palje and Sandala lakes.

As a result of the movement of the earth's crust, depressions are formed in some places over time. Tectonic lakes appear in these depressions. The three most large lakes Kyrgyzstan: Issyk-Kul, Son-Kul and Chatyr-Kul are formed tectonic way.

There are many lakes in the forest-steppe Trans-Urals. Here such large reservoirs as Uelgi, Shablish, Argayash, B. Kuyash, Kaldy, Sugoyak, Tishki, etc. The depths of the lakes on the Trans-Ural plain are noticeably reduced and do not exceed 8-10 m. By their origin, these lakes belong to the erosion-tectonic type. Tectonic depressions have been modified as a result of the impact of erosion processes. Many lakes of the Trans-Urals are confined to the ancient hollows of river runoff (Etkul, Peschanoe, Alakul, Kamyshnoe, etc.).

Lake Baikal. General information

Lake Baikal

Baikal - a freshwater lake in the south Eastern Siberia, it stretched from 53 to 56 ° N. and from 104 to 109 ° 30''E. Its length is 636 km, and the coastline is 2100 km. The width of the lake varies from 25 to 79 km. The total area of \u200b\u200bthe lake (mirror area) is 31,500 sq. Km.

Baikal is the deepest lake in the world (1620 m). It contains the largest reserves of fresh water on earth - 23 thousand cubic kilometers, which is 1/10 of the world's fresh water supply. The complete change of such a huge amount of water in Lake Baikal has been taking place for 332 years.

This is one of the oldest lakes, its age is 15 - 20 million years.

336 rivers flow into the lake, including the Selenga, Barguzin, Upper Angara, and only one Angapa flows out. There are 27 islands on Lake Baikal, the largest of which is Olkhon. The lake freezes in January, opens up in May.

Baikal lies in a deep tectonic depression and is surrounded by mountain ranges covered with taiga; the area around the lake has a complex, deeply dissected relief. Near Baikal, the strip of mountains is noticeably expanding. Mountain ranges stretch here parallel to one another in the direction from north-west to south-east and are separated by hollow-like depressions, along the bottom of which rivers flow and in some places lakes are located. The height of most of the ranges of Transbaikalia rarely exceeds 1300 - 1800, but the highest ridges reach high values. For example, xp. Khamar-Daban (Sokhor peak) - 2 304 m, and the Barguzinsky ridge. about 3000 m.

Tectonic movements continue here to this day. This is evidenced by frequent earthquakes in the region of the basin, outcrops of hot springs and, finally, sinking of significant parts of the coast.

The waters of Lake Baikal are blue-green in color, are distinguished by exceptional purity and transparency, often even greater than in the ocean: you can clearly see stones and thickets of greenish algae lying at a depth of 10 - 15 m, and a white disk immersed in the water is visible at a depth of 40 m.

Baikal lies in the temperate zone.

Geography of Lake Baikal

Lake Baikal is located in the south of Eastern Siberia. In the shape of a nascent crescent, Baikal stretches from southwest to northeast between 55 ° 47 "and 51 ° 28" north latitude and 103 ° 43 "and 109 ° 58" east longitude. The length of the lake is 636 km, the maximum width in the central part is 81 km, the minimum width opposite the Selenga delta is 27 km. Baikal is located at an altitude of 455 m above sea level. Length coastline about 2000 km. The area of \u200b\u200bthe water table, determined at the water edge of 454 m above sea level, is 31,470 square kilometers. The maximum depth of the lake is 1637 m, the average depth is 730 m. 336 permanent rivers and streams flow into Lake Baikal, while the Selenga brings half of the water flowing into the lake. The only river flows out of Lake Baikal - the Angara. However, the question of the number of rivers flowing into Baikal is rather controversial, most likely there are fewer of them than 336. There is no doubt that Baikal is the deepest lake in the world, the closest contender for this title, the African lake Tanganyika, is 200 meters behind. There are 22 islands on Lake Baikal, although, as mentioned above, there is no unanimity on this issue. Most large island - Olkhon.

Lake Baikal age

Usually the age of the lake is given in the literature as 20-25 million years. In fact, the question of the age of Lake Baikal should be considered open, since the use of various methods for determining the age gives values \u200b\u200bfrom 20-30 million to several tens of thousands of years. Apparently, the first estimate is closer to the truth - Baikal is in fact a very ancient lake.

It is believed that Baikal emerged as a result of tectonic forces. Tectonic processes are still going on, which is manifested in the increased seismicity of the Baikal region. If we assume that the age of Lake Baikal is indeed several tens of millions of years, then this is the most ancient lake on Earth.

origin of name

Numerous scientific studies are devoted to the problem of the origin of the word "Baikal", which indicates a lack of clarity in this issue. There are about a dozen possible explanations for the origin of the name. Among them, the most likely is the version of the origin of the name of the lake from the Turkic-speaking Bai-Kul - a rich lake. Of the other versions, two more can be noted: from the Mongolian Baigal - rich fire and Baigal Dalai - big lake... The peoples who lived on the shores of the lake called Baikal in their own way. Evenks, for example, - Lamu, Buryats - Baigal-Nuur, even the Chinese had a name for Baikal - Beihai - North Sea.

The Evenk name Lamu - More was used for several years by the first Russian explorers in the 17th century, then they switched to the Buryat Baigal, slightly softening the letter "g" by phonetic replacement. Quite often Baikal is called the sea, simply out of respect, for its violent disposition, for the fact that the distant opposite shore often hides somewhere in the haze ... At the same time, the Maloye More and the Big Sea are distinguished. Small Sea is located between the northern coast of Olkhon and the mainland, everything else is the Big Sea.

Baikal water

Baikal water is unique and amazing, like Baikal itself. It is unusually transparent, clean and oxygenated. In not so ancient times, it was considered healing, with its help diseases were treated. In spring, the transparency of Baikal water, measured with the Sekki disk (a white disk with a diameter of 30 cm), is 40 m (for comparison, in the Sargasso Sea, which is considered the standard of transparency, this value is 65 m). Later, when a massive algal bloom begins, the transparency of the water decreases, but in calm weather, the bottom is visible from the boat at a fairly decent depth. Such high transparency is explained by the fact that Baikal water, due to the activity of living organisms inhabiting it, is very weakly mineralized and close to distilled. The volume of water in Lake Baikal is about 23 thousand cubic kilometers, which is 20% of the world's fresh water reserves.

They form in places of faults and shifts in the earth's crust. As a rule, these are deep narrow reservoirs with straight-sided steep banks, located in deep through gorges The bottom of such lakes located in Kamchatka is located below the ocean level. Tectonic lakes include Dalneye and Kurilsk. Kuril Lake is located in the south of Kamchatka in a deep picturesque basin surrounded by mountains. The maximum depth of the lake is 306 m. Its banks are steep. Numerous mountain streams flow from them. The lake is a waste water, from which the Ozernaya river starts. On the shores of the lake, hot springs come to the surface, and in the middle there is an island called the Heart-stone. Not far from the lake there is a unique outcrop of pumice stones called Kutkhiny baty. Currently, the lake has been declared a nature reserve and a zoological natural monument.

The bottom profile of tectonic lakes is sharply delineated and looks like a broken curve. Glacial deposits and sediment accumulation processes have little changed the clarity of the tectonic lines of the lake basin. The influence of the glacier on the formation of the basin is noticeable; it leaves traces of its presence in the form of scars, lamb's foreheads, which are clearly visible on rocky shores and islands. The shores of the lakes are composed mainly of hard stone rocks that are poorly eroded, which is one of the reasons for the weak process of sedimentation. These lakes belong to the group of lakes of normal depth (a \u003d 2-4) and deep (a \u003d 4-10). The deep-water zone (more than 10 m) of the total volume of the lake is 60-70%, shallow water (0-5 m) 15-20%. The waters of the lakes are thermally inhomogeneous: during the period of the greatest heating of surface waters, low bottom temperatures remain, which is facilitated by stable thermal stratification. Aquatic vegetation is rare, only in a narrow strip along the shores of closed bays. Typical lakes in the river basin. The Suna are large and medium-sized: Palje, Sundozero, Sandal, as well as the very small lakes Salvilambi and Randozero, located on the private catchments of the Palje and Sandala lakes.

As a result of the movement of the earth's crust, in some places, depressions are formed over time. It is in these depressions that tectonic lakes arise. The three largest lakes in Kyrgyzstan: Issyk-Kul, Son-Kul and Chatyr-Kul are formed by tectonic means.

(Visited 1,060 times, 1 visits today)