Origin of Lake Baikal. Lake Baikal on the map. Age of the Baikal basin. The history of Baikal and its origin
When traveling around Lake Baikal in a kayak, the last thing you think about is that now you have 20% of the world's reserves of the purest fresh water.
This section contains basic information about the lake, and links to the Magic of Baikal pages, where you can get more detailed information. In the process of collecting information, I encountered the fact that data from different sources diverge, sometimes significantly. For example, there is still no generally accepted opinion regarding the number of islands on Baikal, the number of rivers flowing into the lake, etc. The origin of the names of capes, islands, bays and other objects is often a mystery shrouded in darkness. I tried to take information from reliable sources and point out the discrepancies and their reasons. Located in Vladivostok recreation center Rus.
Lake Baikal is located in the south Eastern Siberia. In the form of a crescent being born, Baikal stretched 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 (between the capes Goly on west bank Baikal and Sredny on the east). Baikal is located at an altitude of 455 m above sea level. Length coastline about 1850 km (excluding part of the coast north of the island Yarki). More than half of the lake's shoreline is under the protection of Lake Baikal environmental organizations.
The area of the water mirror, determined at the water's edge of 454 m above sea level, is 31,470 square kilometers. The maximum depth of the lake is 1637 m, average depth- 730 m. Sometimes in the literature there is a statement that the maximum depth of Baikal is 1642 m. Which value is correct? The answer to this question is somewhat paradoxical - both are correct. The fact is that the measurement error of such depths is about 2%, i.e. 30 meters. Therefore, it is correct to say that the greatest depth of Baikal is 1640 m.
336 permanent rivers and streams flow into Baikal, while half of the water entering the lake comes from the Selenga. flows out of Baikal the only river- Angara. However, the question of the number of rivers flowing into Baikal is rather controversial, most likely there are fewer than 336. There is no doubt that Baikal is the most deep lake in the world, the closest contender for this title, African lake Tanganyika, lags behind by as much as 200 meters. There are 30 islands on Baikal, although, as mentioned above, there is no unanimity on this issue. The largest is Olkhon Island.
Age of Lake Baikal.
The age of the lake is usually given in the literature as 20-25 million years. In fact, the question of the age of Baikal should be considered open, since the use of various methods for determining the age gives values from 20-30 million to several tens of thousands of years. Apparently, the first estimate is closer to the truth - Baikal is really very ancient lake. If we assume that the age of Baikal is indeed several tens of millions of years, then this is the oldest lake on Earth.
It is believed that Baikal arose as a result of the action of tectonic forces. Tectonic processes are still going on, which is manifested in the increased seismicity of the Baikal region.
Origin of name.
Numerous scientific studies have been devoted to the problem of the origin of the word "Baikal", which indicates a lack of clarity in this matter. There are about a dozen possible explanations for the origin of the name. Among them, the most probable 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 - a 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 - the North Sea.
The Evenk name Lamu - the Sea 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 temper, for the fact that the far opposite coast is often hidden somewhere in the haze. At the same time, the Small Sea and the Big Sea are distinguished. Small Sea - what is located between north coast Olkhon and the mainland, everything else is the Big Sea.
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Experts still cannot determine the exact age of the reservoir - presumably 25-35 million years. And this main riddle of the many: after all, the lakes exist for about 10-15 thousand years, after which they turn into a swamp or finally dry up. Baikal not only does not age - on the contrary, the researchers note that the formation continues to this day. Each year, its banks diverge by 2 cm. Therefore, many experts believe that amazing lake- and not a lake at all, but a nascent ocean.
Although in Lately, at the suggestion of the doctor of geological and mineralogical sciences Alexander Tatarinov, the version about the relative youth of Baikal is increasingly being discussed. And there is evidence, albeit indirect, for this. It is enough to look deeper into the history of Baikal. Investigating the material composition of bottom sediments and the physical and chemical processes occurring in them, scientists came to the conclusion that the shoreline of the lake is about 8 thousand years old, and the deep-water parts are about 150 thousand years old.
There are many assumptions about how the miracle lake appeared.
Some experts believe that the depression was formed in the Precambrian period by the confluence of three basins: in the Lower Cambrian era, they made up three bays of the Lower Cambrian Sea. Then the sea receded, and these three basins remained closed. Subsequently, over many years and epochs, erosion destroyed the barriers between them and connected the basins to each other.
The Baikal basin appeared due to a long process of subsidence, which continues to this day, others believe.
Some scientists suggest that the formation of the lake is associated with its location within the boundaries of a transform fault, others believe that the formation of Baikal is associated with the presence of a hot mantle flow under it. There is also an opinion that the lake appeared as a result of shifts of a huge fault that crosses Eurasia from the southwest to the northeast. The Baikal depression, according to this theory, was formed due to a fault that ran at an angle to the main fault. Such a mechanism is called "pull-apart" in the literature. This explains the rhombic shape of the Baikal depression, as well as tectonic movements during earthquakes.
The latest results obtained using the seismic tomography method in the Laboratory of Geodynamics and Paleomagnetism of the Institute of Geology of the Siberian Branch of the Russian Academy of Sciences allowed us to take a fresh look at this problem and propose a scheme for the formation and evolution of the Baikal region.
Thus, geologists do not yet have exact data on the time of the origin of Baikal. At the same time, there are currently no grounds to deny its existence back in the Cenozoic era. It is obvious that the history of the emergence of Baikal will worry scientists around the world for a long time to come.
Lake Baikal
The crescent of the lake is located in the very center of the Baikal rift zone - a break in the earth's crust in the continental part of Eurasia. There is constantly high seismic activity. In the very basin of the lake there is a continuous anomalous heating of the earth's interior. Scientists believe that heated substances could lift the earth's crust, deforming and cracking it. As a result of this movement, a chain of ridges surrounding the lake was probably formed.
What is certain is that the lake is located in a rift basin and is similar in structure, for example, to the Dead Sea basin. Some researchers explain the formation of Baikal by its location in the zone of a transform fault, others suggest the presence of a mantle plume under the lake, and others explain the formation of the basin by passive rifting as a result of the collision of the Eurasian plate and Hindustan.
Be that as it may, the transformation of Baikal continues to this day - earthquakes constantly occur in the vicinity of the lake, which means that the history of Baikal will continue. There are suggestions that the subsidence of the basin is associated with the formation of vacuum chambers due to the outpouring of basalts on the surface (Quaternary period).
In 1996 the lake was listed world heritage UNESCO.
Baikal is located almost in the center of Asia. Its length is 636 km, maximum width 81 km, the length of the coastline is about 2 thousand km. The area is 31.5 thousand square kilometers, and here it is second only to the Caspian, Victoria, Tanganyika, Huron, Michigan and Upper and ranks seventh among the world's lakes. Baikal is the deepest lake in the world: 1637 m, its average depth is 730 m. But on the other hand, it is unrivaled in terms of water volume among the fresh lakes of the world. 23 thousand cubic km of Baikal waters - neither more nor less - 20% of the world and 80% of Russia's water reserves. Moreover, there is more water in Baikal than in all the Great American Lakes taken together.
"Baikal" - the history of the name
The most common version is that “Baikal” is a Turkic-speaking word, comes from “bay” - rich, “kul” - lake, which means “rich lake”. However, there is evidence that in the past different peoples called the lake differently.
Chinese in ancient chronicles 110 BC the Mongols called it "Beihai" - the northern sea, the Mongols - "Tengis", "Tengis-dalai", the Buryat-Mongols - "Baigaal-dalai" - a large body of water, the ancient peoples of Siberia - "Lamu", which means the sea. Under the name "Lamu" the lake is often mentioned in Evenk legends, and it was under this name that Russian explorers first became known.
After the first Russian detachment came to the shore of the lake in 1643 under the leadership of Kurbat Ivanov, the Russians switched to the Buryat-Mongolian name "Baigaal" or "Baigaal-dalai". At the same time, they linguistically adapted it to their language, replacing the “g” characteristic of the Buryats with the more familiar “k” for the Russian language - Baikal.
The history of the discovery of Baikal
One of the most important stages in the exploration of Siberia can rightfully be considered the discovery of Lake Baikal. The Russians first came here in 1643, when the Cossack Kurbat Ivanov with his detachment got from Verkhnelensky prison to west coast lake, going to it directly opposite the island of Olkhon. Ivanov compiled a "Drawing of Baikal and falling rivers and lands to Baikal" - the first schematic map of the places visited by the Cossacks. This is how the history of Baikal began.
Two years later, ataman Vasily Kolesnikov prepared a detachment of hundreds of Cossacks and went to Baikal in search of silver ore, which, according to rumors, was in abundance in these parts. Having sailed to the northern end of the lake, he founded the Verkhneangarsky prison, which became a staging post for moving further, in Transbaikalia and on Far East.
One of the main events of these years was the foundation by Yakov Pokhabov in 1661 of the Irkutsk prison on the right bank of the Angara opposite the mouth of the Irkut. And for three and a half centuries, Baikal has been inextricably linked with Irkutsk, the city that has become its “gateway”. Anyone who comes to the Baikal region will certainly stop at.
It is impossible not to mention Archpriest Avvakum, a prominent church leader of the 17th century, who was exiled to Siberia for his Old Believer views. In his Life of Archpriest Avvakum, he vividly described what he saw on his way to exile in the 1650s: The water is fresh, seals and hares are great in it: in the ocean-sea, living on the Mezen, I have not seen such. For the first time, Baikal and its environs were described in such detail.
One of the first explanations regarding the appearance of Lake Baikal was put forward by members of the expedition of the St. Petersburg Academy of Sciences at the end of the 18th century. German researchers Johann Georgi and Peter Pallas, who collaborated with the Academy at the invitation of Catherine II, believed that the lake basin was formed after a tectonic failure of part of the land, which was caused by a natural disaster.
The reason for the failure, Georgi believed, was a powerful earthquake, which could well even affect the course of the course of local rivers.
A century later, the political exile Jan Chersky, a Pole, put forward his own version of the origin of Baikal. He relied on his observations and research, which he made during his travels around the lake. The talented scientist suggested that the basin and the mountains around it arose after the slow earth's crust in a horizontal direction.
Since then, many scientists have put forward their own arguments in favor of one hypothesis or another, which often differed only in small details. V.A. came closest to the modern understanding of the problem of Baikal formation. Obruchev. In his opinion, Baikal was formed together with mountain system Siberia.
Obruchev believed that the depression, which later became a lake, arose after the subsidence of land along two fracture surfaces that followed in a vertical direction.
A modern view on the problem of the emergence of Baikal
Only scientific achievements last century. When geologists and geophysicists discovered the existence of a global system of faults in the earth's crust, it turned out that the appearance of Baikal became part of the processes that took place on a global scale. The researchers found that several depressions on Earth have a nature similar to Baikal. Examples are lakes Tanganyika and Nyasa, as well as the Red Sea.
According to scientists, the tectonic processes that led to the formation of the lake began more than 30 million years ago.
The Baikal basin is considered today central part rift of the same name, that is, a depression formed after the shift of the earth's crust. The length of the rift is more than two thousand kilometers. The depression is located between two powerful lithospheric plates. At first, geophysicists believed that the lake basin arose as a result of the collision of these plates, but then there was an assumption that an increase in the temperature of the mantle located under the Baikal depression was added to their interaction.
Baikal(bur. Baigal dalai, Baigal nuur) - lake tectonic origin in the southern part of Eastern Siberia, the deepest lake in the world and the largest (by volume) reservoir of watery fresh water. It contains about 19% of the global supply of fresh water. The lake is located in the rift plain in Eastern Siberia on the border Irkutsk region and the Republic of Buryatia. 336 rivers flow into it, many of which are the Selenga, Upper Angara, Barguzin and others, and one river flows out - the Angara.
Information about Baikal:
Geographical location and dimensions of the basin
Baikal is located in the center of Asia, in Russia, on the border of the Irkutsk region and the Republic of Buryatia. The lake stretches from northeast to southwest for 620 km in the form of a huge crescent. The width of Lake Baikal ranges from 24 to 79 km. There is no other deepest lake on earth. The bottom of Baikal is 1167 meters below the level of the World Ocean, and the mirror of its waters is 453 meters higher.
The area of the aquatic surface is 31,722 km² (excluding islands), which is approximately equal to the area of \u200b\u200bsuch states as Belgium, the Netherlands or Denmark. Baikal ranks sixth among the largest lakes in the world in terms of the area of its water surface.
The lake is located in a specific basin, surrounded on all sides by mountain ranges and hills. With all this, the western coast is rocky and steep, the relief east coast- more gentle (in some places the mountains recede from the coast for 10 km).
Depth
Baikal is the deepest lake on the planet Earth. Modern meaning the greatest depth of the lake - 1637 m - was established in 1983 by L.G. Kolotilo and A.I. Sulimov during the performance of hydrographic work by the expedition of the GUNiO of the USSR Ministry of Defense at the point with coordinates 53 ° 14 "59" N. latitude. 108°05"11" E
The greatest depth was mapped in 1992 and proved in 2002 as a result of a joint Belgian-Spanish-Russian project to create the latest bathymetric map of Baikal, when the depths were digitized at 1,312,788 points of the lake’s water area (the depth values were obtained as a result of recalculation acoustic sounding data combined with additional bathymetric information, including echolocation and seismic profiling; one of the creators of the discovery of the greatest depth, L.G. Kolotilo, was a participant in this project).
If we take into account that the water surface of the lake is located at an altitude of 453 m above sea level, then the lower point of the basin lies 1186.5 m below the level of the world ocean, which makes the Baikal bowl also one of the deepest continental depressions.
The average depth of the lake is also very large - 744.4 m. It exceeds greatest depths many very deep lakes.
Apart from Baikal, only two lakes on Earth have a depth of more than 1000 meters: Tanganyika (1470 m) and the Caspian Sea (1025 m). According to some data, the subglacial Lake Vostok in Antarctica has a depth of more than 1200 m, but it must be taken into account that this subglacial “lake” is not a lake in the sense that we are used to, because there are four kilometers of ice above the water and it is a kind of closed container, where the water is under tremendous pressure, and the "surface" or "level" of water in different parts of this "lake" differs by more than 400 meters. Consequently, the concept of "depth" for the subglacial Lake Vostok is fundamentally different from the depth of "ordinary" lakes.
Water volume
Water reserves in Baikal are huge - 23,615.39 km³ (about 19% of global fresh water reserves - in all fresh lakes the world contains 123 thousand km³ of water). In terms of water reserves, Baikal occupies the 2nd place in the world among lakes, second only to the Caspian Sea, but the water in the Caspian Sea is salty. There is more water in Baikal than in all 5 Great Lakes taken together, and 25 times more than in Lake Ladoga.
Tributaries and runoff
336 rivers and streams flow into Baikal, but this number takes into account only constant tributaries. The largest of them are Selenga, Upper Angara, Barguzin, Turka, Snezhnaya, Sarma. One river flows out of the lake - the Angara.
Water characteristics
Baikal water is very transparent. The main characteristics of Baikal water can be briefly described as follows: it contains very few dissolved and suspended mineral substances, negligible organic impurities, and a lot of oxygen.
The water in Baikal is cool. Temperature surface layers even in summer it does not exceed +8…+9°C, in some bays - +15°C. The temperature of the deep layers is about +4°C. Only in the summer of 1986 did the surface water temperature in the northern part of Baikal rise to a record 22-23°C.
The water in the lake is so transparent that individual pebbles and various objects can be seen at a depth of 40 m. At this time Baikal water happens to be blue. In summer and autumn, when a mass of plant and animal organisms develop in the water warmed by the sun, its transparency drops to 8-10 m, and the color becomes blue-green and green. Pure and clearest water Baikal contains so few mineral salts (96.7 mg/l) that it can be used instead of distilled water.
The freezing period is on average January 9 - May 4; Baikal freezes completely, not counting a small, 15-20 km long section located at the source of the Angara. The sailing period for passenger and cargo ships is usually from June to September; research vessels begin navigation right after the ice breaks up the lake and complete it with the freezing of Lake Baikal, in other words, from May to January.
By the end of winter, the ice thickness on Baikal reaches 1 m, and in the bays - 1.5-2 m. severe frost cracks, which have a local name "stanovye cracks", break the ice into separate fields. The length of such cracks is 10-30 km, and the width is 2-3 m. Breaks occur once a year in approximately the same areas of the lake. They are accompanied by a sonorous crack, reminiscent of thunder or cannon shots. It seems to a person standing on the ice that the ice cover is bursting just under his feet and he this moment fall into the abyss. Thanks to the cracks in the ice, the fish in the lake do not die from a lack of oxygen. Baikal ice, in addition, is very transparent, and the sun's rays fall through it, therefore planktonic aquatic plants that produce oxygen rapidly develop in the water. It is possible to follow along the shores of Lake Baikal in winter ice grottoes and splashes.
Baikal ice presents scientists with many mysteries. So, in the 1930s, specialists from the Baikal Limnological Station found unusual forms of ice cover, corresponding only to Baikal. For example, “hills” are cone-shaped ice mounds up to 6 m high, hollow inside. Appearance they resemble ice tents, "open" in the opposite direction from the coast. The hills can be placed separately, and from time to time they form small " mountain ranges". There are also a number of other types of ice on Baikal: “sokuy”, “kolobovnik”, “autumn”.
In addition, in the spring of 2009, the Internet was widely distributed satellite imagery various parts of Lake Baikal, where they were found dark rings. According to scientists, these rings appear due to the rise of deep waters and an increase in the temperature of the surface layer of water in the central part of the ring structure. As a result of this process, an anticyclonic (clockwise) direction appears. In the zone where the direction achieves the highest velocities, the vertical water exchange increases, which leads to accelerated destruction of the ice cover.
Bottom relief
The bottom of Lake Baikal has a pronounced relief. Along the entire coast of Baikal, coastal shallow waters (shelves) and underwater slopes are developed to a greater or lesser extent; the bed of 3 main basins of the lake is expressed; there are underwater banks and even underwater ridges.
The Baikal basin is divided into three basins: Southern, Middle and Northern, separated from each other by 2 ridges - Akademichesky and Selenginsky.
More expressive is the Academic Ridge, which stretches along the bottom of Lake Baikal from Olkhon Island to the Ushkany Islands (which are its highest part). Its length is about 100 km, highest altitude above the bottom of Lake Baikal 1848 m. The thickness of bottom sediments in Baikal reaches about 6 thousand m, and highest mountains on Earth, with a height of more than 7000 m.
Islands and peninsulas
There are 27 islands on Baikal (Ushkany Islands, Olkhon Peninsula, Yarki Peninsula and others), the largest of them is Olkhon (71 km long and 12 km wide, located almost in the center of the lake near its western coast, the area is 729 km², according to other data - 700 km²), most largest peninsula- Holy Nose.
seismic activity
The Baikal region (the so-called Baikal rift zone) is one of the areas with the highest seismicity: earthquakes constantly occur here, the strength of most of which is one or two points on the MSK-64 intensity scale. But there are also strong ones; So, in 1862, during the ten-point Kudarinsky earthquake in the northern part of the Selenga delta, a land area of 200 km² with 6 uluses, in which 1300 people lived, went under water, and Proval Bay was formed. Strong earthquakes were also recorded in 1903 (Baikal), 1950 (Mondinskoe), 1957 (Muiskoe), 1959 (Middle Baikal). The epicenter of the Middle Baikal earthquake was located at the bottom of Lake Baikal near the village of Sukhaya ( southeast coast). His strength reached 9 points. In Ulan-Ude and Irkutsk, the force of the head shock reached 5-6 points, cracks and minor damage were observed in buildings and structures. The last strong earthquakes on Baikal occurred in August 2008 (9 points) and in February 2010 (6.1 points).
Climate
Baikal winds often raise a storm on the lake. The water mass of Baikal influences the climate of the coastal area. Winter is milder here summer time- cooler. The arrival of spring on Baikal is delayed by 10-15 days compared to the surrounding areas, and autumn is often quite long.
The Baikal region is distinguished by a large total duration of sunshine. For example, in the village of Huge Goloustnoye, it reaches 2524 hours, which is more than in the Black Sea resorts, and is a record for Russia. There are only 37 days in the absence of the sun in the same inhabited Friday, and 48 on the Olkhon Peninsula.
The special features of the climate are justified Baikal winds, which have their own names - barguzin, sarma, verkhovik, kultuk.
Origin of the lake
The origin of Baikal still causes scientific controversy. Scientists usually determine the age of the lake at 25-35 million years. This fact also makes Baikal unique natural object, because most of lakes, separate glacial origin, live an average of 10-15 thousand years, and later they are filled with silty sediments and become swampy.
But there is also a version about the youth of Baikal, put forward by A.V. Tatarinov in 2009, which received circumstantial evidence during the second step of the Mirs expedition to Baikal. Namely, the activity of mud volcanoes at the bottom of Lake Baikal allows scientists to believe that the modern coastal strip of the lake is only 8 thousand years old, and the deep-water part is 150 thousand years old.
Of course, only that the lake is located in a rift basin and is similar in structure, for example, to the Dead Sea basin. Some researchers explain the formation of Baikal by its location in the transform fault zone, others imply the presence of a mantle plume under Baikal, and others explain the formation of the basin by passive rifting as a result of the collision of the Eurasian plate and Hindustan. Be that as it may, the transformation of Baikal continues to this day - earthquakes constantly occur in the lake districts. There are speculations that the subsidence of the basin is associated with the formation of vacuum chambers due to the outpouring of basalts on the surface (Quaternary period).
Additional information on the site about lakes:
Baikal(bur. Baigal dalai, Baigal nuur) is a lake of tectonic origin in the southern part of Eastern Siberia, the deepest lake in the world and the largest (by volume) reservoir of liquid fresh water. It contains about 19% of the world's fresh water. The lake is located in rift valley in Eastern Siberia on the border of the Irkutsk region and the Republic of Buryatia. 336 rivers flow into it, including the Selenga, Upper Angara, Barguzin, and others, and one river, the Angara, flows out.
Information about Baikal:
- Area - 31,722 km 2
- Volume - 23,615 km 3
- The length of the coastline is 2100 km
- The greatest depth is 1642 m
- Average depth - 744 m
- Height above sea level - 456 m
- Water transparency - 40 m (at a depth of up to 60 m)
Geographical location and dimensions of the basin
Baikal is located in the center of Asia, in Russia, on the border of the Irkutsk region and the Republic of Buryatia. The lake stretches from northeast to southwest for 620 km in the form of a giant crescent. The width of Lake Baikal ranges from 24 to 79 km. There is no other lake so deep on earth. The bottom of Lake Baikal is 1167 meters below the level of the World Ocean, and the mirror of its waters is 453 meters higher.
The water surface area is 31,722 km² (excluding islands), which is approximately equal to the area of countries such as Belgium, the Netherlands or Denmark. In terms of the area of the water surface, Baikal ranks sixth among the largest lakes in the world.
The lake is located in a kind of basin, surrounded on all sides by mountain ranges and hills. At the same time, the western coast is rocky and steep, the relief of the eastern coast is more gentle (in some places the mountains recede from the coast for tens of kilometers).
Depth
Baikal is the deepest lake on the planet Earth. The modern value of the maximum depth of the lake - 1637 m - was established in 1983 by L.G. Kolotilo and A.I. Sulimov during the performance of hydrographic work by the expedition of the GUNiO of the USSR Ministry of Defense at the point with coordinates 53°14′59″ N. 108°05′11″ E
The maximum depth was mapped in 1992 and confirmed in 2002 as a result of a joint Belgian-Spanish-Russian project to create a new bathymetric map of Baikal, when the depths were digitized at 1,312,788 points of the lake water area (the depth values were obtained as a result of recalculation acoustic sounding data combined with additional bathymetric information, including echolocation and seismic profiling; one of the authors of the maximum depth discovery, L.G. Kolotilo, was a participant in this project).
If we take into account that the water surface of the lake is located at an altitude of 453 m above sea level, then the lower point of the basin lies 1186.5 m below the level of the world ocean, which makes the Baikal bowl also one of the deepest continental depressions.
The average depth of the lake is also very large - 744.4 m. It exceeds the maximum depths of many very deep lakes.
In addition to Baikal, only two lakes on Earth have a depth of more than 1000 meters: Tanganyika (1470 m) and the Caspian Sea (1025 m). According to some reports, the subglacial Lake Vostok in Antarctica has a depth of more than 1200 m, but it must be borne in mind that this subglacial “lake” is not a lake in the sense that we are used to, since there are four kilometers of ice above the water and it is a kind of closed container, where the water is under enormous pressure, and the "surface" or "level" of water in different parts of this "lake" differs by more than 400 meters. Thus, the concept of "depth" for the subglacial Lake Vostok is fundamentally different from the depth of "ordinary" lakes.
Water volume
The water reserves in Baikal are gigantic - 23,615.39 km³ (about 19% of the world's fresh water reserves - all fresh lakes in the world contain 123 thousand km³ of water). In terms of water reserves, Baikal ranks second in the world among lakes, second only to the Caspian Sea, but the water in the Caspian Sea is salty. There is more water in Baikal than in all five Great Lakes taken together, and 25 times more than in Lake Ladoga.
Tributaries and runoff
336 rivers and streams flow into Baikal, but this number takes into account only permanent tributaries. The largest of them are Selenga, Upper Angara, Barguzin, Turka, Snezhnaya, Sarma. One river flows out of the lake - the Angara.
Water properties
Baikal water is extremely transparent. The main properties of Baikal water can be briefly described as follows: it contains very few dissolved and suspended mineral substances, negligibly few organic impurities, and a lot of oxygen.
The water in Baikal is cold. The temperature of the surface layers even in summer does not exceed +8…+9°C, in some bays - +15°C. The temperature of the deep layers is about +4°C. Only in the summer of 1986 did the surface water temperature in the northern part of Baikal rise to a record 22-23°C.
The water in the lake is so transparent that individual stones and various objects can be seen at a depth of 40 m. At this time, the Baikal water is blue. In summer and autumn, when a lot of plant and animal organisms develop in the water warmed by the sun, its transparency decreases to 8-10 m, and the color becomes blue-green and green. The purest and most transparent water of Lake Baikal contains so few mineral salts (96.7 mg/l) that it can be used instead of distilled water.
The freezing period is on average January 9 - May 4; Baikal freezes over entirely, except for a small area, 15-20 km long, located at the source of the Angara. The sailing period for passenger and cargo ships is usually from June to September; research vessels begin navigation after the ice breaks up the lake and complete it with the freezing of Lake Baikal, that is, from May to January.
By the end of winter, the thickness of ice on Baikal reaches 1 m, and in the bays - 1.5-2 m. In severe frosts, cracks, locally called "stanovo cracks", break the ice into separate fields. The length of such cracks is 10-30 km, and the width is 2-3 m. Breaks occur annually in approximately the same areas of the lake. They are accompanied by a loud crack, reminiscent of thunder or cannon shots. It seems to a person standing on the ice that the ice cover is bursting just under his feet and he will now fall into the abyss. Thanks to cracks in the ice, fish in the lake do not die from lack of oxygen. Baikal ice is also very transparent, and the sun's rays penetrate through it, so planktonic algae, which release oxygen, flourish in the water. Along the shores of Lake Baikal, one can observe ice grottoes and splashes in winter.
Baikal ice presents scientists with many mysteries. So, in the 1930s, specialists from the Baikal Limnological Station discovered unusual forms of ice cover, typical only for Lake Baikal. For example, “hills” are cone-shaped ice hills up to 6 m high, hollow inside. Appearance they resemble ice tents, "open" in the opposite direction from the coast. Hills can be located separately, and sometimes form miniature "mountain ranges". Also on Baikal there are several more types of ice: "sokuy", "kolobovnik", "autumn".
In addition, in the spring of 2009, satellite images of different parts of Lake Baikal were distributed on the Internet, on which dark rings were found. According to scientists, these rings arise due to the rise of deep waters and an increase in the temperature of the surface layer of water in the central part of the ring structure. As a result of this process, an anticyclonic (clockwise) current is formed. In the area where the current reaches maximum speeds, vertical water exchange increases, which leads to accelerated destruction of the ice cover.
Bottom relief
The bottom of Lake Baikal has a pronounced relief. Along the entire coast of Baikal, coastal shallow waters (shelves) and underwater slopes are more or less developed; the bed of the three main basins of the lake is expressed; there are underwater banks and even underwater ridges.
The Baikal basin is divided into three basins: Southern, Middle and Northern, separated from each other by two ridges - Akademichesky and Selenginsky.
The most expressive is the Academic Ridge, which stretches along the bottom of Lake Baikal from Olkhon Island to the Ushkany Islands (which are its most high part). Its length is about 100 km, maximum height above the bottom of Lake Baikal 1848 m. The thickness of bottom sediments in Baikal reaches about 6 thousand m, and as established by gravimetric survey, one of the highest mountains on Earth, more than 7000 m high, is flooded in Baikal.
Islands and peninsulas
There are 27 islands on Baikal (Ushkany Islands, Olkhon Island, Yarki Island and others), the largest of them is Olkhon Island (71 km long and 12 km wide, located almost in the center of the lake near its western coast, area - 729 km², according to other sources - 700 km²), the largest peninsula is Svyatoy Nos.
seismic activity
The Baikal region (the so-called Baikal rift zone) belongs to areas with high seismicity: earthquakes regularly occur here, the strength of most of which is one or two points on the MSK-64 intensity scale. However, there are also strong ones; So, in 1862, during the ten-point Kudarinsky earthquake in the northern part of the Selenga delta, a land area of 200 km² with 6 uluses, in which 1300 people lived, went under water, and Proval Bay was formed. Strong earthquakes were also recorded in 1903 (Baikal), 1950 (Mondinskoe), 1957 (Muiskoe), 1959 (Middle Baikal). The epicenter of the Middle Baikal earthquake was located at the bottom of Baikal near the village of Sukhaya (southeast coast). His strength reached 9 points. In Ulan-Ude and Irkutsk, the strength of the main shock reached 5-6 points, cracks and minor damage were observed in buildings and structures. The last strong earthquakes on Baikal occurred in August 2008 (9 points) and in February 2010 (6.1 points).
Climate
Baikal winds often raise a storm on the lake. The water mass of Lake Baikal influences the climate of the coastal area. Winters are milder here, and summers are cooler. The onset of spring on Baikal is delayed by 10-15 days compared to the surrounding areas, and autumn is often quite long.
The Baikal region is distinguished by a large total duration of sunshine. For example, in the village of Bolshoe Goloustnoye it reaches 2524 hours, which is more than in the Black Sea resorts, and is a record for Russia. Days without sun in the same year locality there are only 37, and on the island of Olkhon - 48.
The special features of the climate are due to the Baikal winds, which have their own names - barguzin, sarma, verkhovik, kultuk.
Origin of the lake
The origin of Baikal still causes scientific controversy. Scientists traditionally determine the age of the lake at 25-35 million years. This fact also makes Baikal a unique natural object, since most of the lakes, especially of glacial origin, live on average 10-15 thousand years, and then they are filled with silty sediments and become swampy.
However, there is also a version about the youth of Baikal, put forward by Doctor of Geological and Mineralogical Sciences A.V. Tatarinov in 2009, which received indirect confirmation during the second stage of the Mirs expedition to Baikal. In particular, the activity of mud volcanoes at the bottom of Lake Baikal allows scientists to assume that the modern coastline of the lake is only 8 thousand years old, and the deep-water part is 150 thousand years old.
What is certain is that the lake is located in a rift basin and is similar in structure, for example, to the Dead Sea basin. Some researchers explain the formation of Baikal by its location in the zone of a transform fault, others suggest the presence of a mantle plume under Baikal, and others explain the formation of the basin by passive rifting as a result of the collision of the Eurasian plate and Hindustan. Be that as it may, the transformation of Baikal continues to this day - earthquakes constantly occur in the vicinity of the lake. There are suggestions that the subsidence of the basin is associated with the formation of vacuum chambers due to the outpouring of basalts on the surface (Quaternary period).
Sources and additional information:
- ru.wikipedia.org - article about Baikal in Wikipedia;
- lake-baikal.narod.ru - Lake Baikal in questions and answers. Basic figures;
- magicbaikal.ru - site "Magic of Baikal";
- shareapic.net - map of Lake Baikal;
- chemezova.ru — helpful information about the rest of Baikal.
