What is the origin of Lake Baikal. Origin of lakes Sources and additional information

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.

Origin of Lake Baikaldescribed in the legends of the Buryats - the indigenous inhabitants of the Baikal region. They gave the name to Lake Baigal. According to legend, the earth cracked, and fire broke out from there. In horror, people shouted: "Bye, gall!" (“fire, stop!”). The fire went out and the crack filled with water. So, according to legend, the lake and its name appeared. There are other beautiful legends about the origin of the lake. According to one of them, the old man Baikal mourned his runaway daughter Angara and cried out a whole lake. According to another legend, a golden chariot with a fiery dragon descended from the sky. From the blow of his tail, the earth shook, a crevice formed, ice melted on the tops of the mountains, and a lake formed. These are all beautiful myths, but what really happened?

Location and dimensions

Baikal is in the south Eastern Siberia. The lake has the shape of a crescent and is elongated in a direction approximately from north to south. The longitudinal dimension is about 640 km. The transverse size ranges from 25 km to 79 km. The contour of the coastline is 2 thousand km. This is one of largest lakes on the ground.

The basin of the lake is divided into three separate parts - Southern, Middle, Northern. They have different depths. The deepest of them is the Middle - 1642 m. The northern and middle basins are separated by the Akademichesky ridge. Only in some parts of the lake the peaks of the ridge protrude above the water and form islands. Between the Southern and Middle depressions is the Selenga bridge. This structure is hidden by the waters of Lake Baikal.

The sides of the basin are asymmetric. western slope goes sharply down, and the eastern one is more gentle. The relief of the slopes is also different. The eastern coast is with underwater valleys, canyons, and the western coast is almost without dismemberment. The bottom of all depressions is leveled and has a slight slope to west bank. The bottom depth gradually decreases due to river sediments.

The lake is surrounded by mountains. They are made up of:

• Granite.
• Marble.
• Gneiss.
• Slate.
• Jade.
• Magnetite.
• Quartz.
• Lapis lazuli.

earthquakes

In the Baikal zone, the seismic background is high, and earthquakes are very frequent. Their strength is small - 1-2 points. But there are catastrophic aftershocks. So, as a result of an earthquake in the middle of the 19th century. with a force of 10 points, Proval Bay was formed. Its depth reaches 6 m, and the area is almost 200 km². Almost 100 years later, as a result of the same event, the bottom of the Middle Basin sank by 15-20 m.

Not now active volcanoes, but geologists are still studying their past activities. The origin of Lake Baikal and the current formation is associated with seismic activity in this zone. So, it is known that the shores of this lake diverge by 2 cm per year.

Glaciers

During the ice age, the relief of Baikal underwent changes. These traces are visible in the wreckage rocks under ice, sediment and bottom sediments. Geologists suggest that the thickness of the descending glaciers was 80-120 m. Perhaps there was no permanent ice cover. Otherwise life in the lake could not be. However, among the inhabitants now living in the lake there are golomyankas, sponges, amphipods, sculpins, flatworms. These organisms originated before this period.

Age

It is believed that Baikal is supposedly 25 million years old. However, this fact causes surprise and controversy about the age of the lake. The fact is that the lake usually does not live that long. This applies especially to those lakes that are of glacial origin. They exist for 10-15 thousand years, then they are filled with silt and disappear. There is speculation that it may be younger. At the same time, it is believed that the deep-sea part is 150 thousand years old, and the coastal part is only 8 thousand years old.

Versions

There is no consensus on the formation of Baikal. One thing is obvious, that it is located in the rift basin. Several versions of the formation of this lake were put forward:

• As a result of the failure of land during an earthquake (Pallas' hypothesis).
• As a result of compression of the earth's crust in a horizontal direction (Chersky's hypothesis).
• As a result of land subsidence along fault surfaces (Obruchev's hypothesis).
• As a result of processes in the world rift system, the Baikal rift (fault of the earth's crust).

And which version is closer to you?

lake formation process

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 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 east coast- more gentle (in some places the mountains recede from the coast for tens of kilometers).

Depth

Baikal is the most deep lake planet Earth. Modern meaning 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

Max 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’s water area (the depth values ​​were obtained as a result of recalculation of acoustic sounding 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 - in all fresh lakes the world contains 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 the temperature surface water in the northern part of Baikal rose 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 Baikal water happens to be 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. 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 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 ice thickness on Baikal reaches 1 m, and in the bays - 1.5-2 m. severe frost cracks, which are locally called "stave gaps", 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. On the shores of Lake Baikal can be observed in winter ice grottoes and splashes.

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, Internet satellite imagery different parts of Baikal where they were found dark rings. 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 zone where the current reaches maximum speeds, the vertical water exchange intensifies, 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 west coast, area - 729 km², according to other sources - 700 km²), largest peninsula- Holy Nose.

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 Lake 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 unique. natural object, since most lakes, especially glacial origin, live an average of 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.

Lake Baikal is the deepest on the planet Earth, as well as the richest fresh water(slightly less than 20% of world reserves are concentrated in this reservoir). Let's get acquainted with the origin of the basin of Lake Baikal and learn some interesting facts about it.

Description of the reservoir

This amazing lake is located in Eastern Siberia, on the border of the Buryat Republic and the Irkutsk region. The features of the reservoir are:

• Area - more than 31 thousand square meters. km.
• Volume - more than 23,615 cubic meters. km.
• The length of the coastline is 2.1 thousand km.
• The length of Lake Baikal is over 630 km.
• The deepest section is 1.6 km.
• Average depth - 740 m.
• More than 330 rivers flow into it, the largest of which are the Barguzin, Selenga, Turka, Upper Angara.

The reservoir has the shape of a crescent, the width of which is from 25 to almost 80 km. Interestingly, the giant lake is equal in size to the areas of such states as Denmark or Belgium. Located on the territory of the Asian part of the Russian Federation, Baikal is surrounded on all sides by mountains and hills, in the west its coast is steep, towards the east it becomes gentle.

Briefly about depth

This unusual reservoir is a true leader, since the greatest depth of Lake Baikal is 1637 meters. This value was identified during a hydrographic survey in 1983. The data were later confirmed in 2002, during a joint study by several countries:

• Russia;
• Belgium;
• Spain.

It is interesting that the surface of the lake is located at an altitude of just over 450 m above the level of the World Ocean, while the lowest point is located at a depth of more than 1180 m below sea level. Therefore, the bowl of the deepest lake on the planet becomes the deepest among the continental depressions.

The average depth indicator is also amazing, more than 744 meters. It is known that there are only two lakes on the planet with places more than a kilometer deep:

• Tanganyika.
• The Caspian Sea (despite the name, this is also a lake).

But the deepest section of Baikal is almost 200 meters higher than the similar place of Tanganyika.

Origin theories

Consider the origin of Lake Baikal, which is this moment has not yet been fully explored and is controversial in scientific world. First we present scientific facts which are recognized by all researchers:

• The reservoir is located in the rift basin.
• Its structure is in many ways reminiscent of the Dead Sea.

But what caused the formation of this fault? Further opinions of scientists differ:

• According to the first theory, Lake Baikal, whose area is more than 31 thousand km 2, is located in the area of ​​a transform fault. That is why it has become so profound.
• There is an opinion that there is a mantle plume under the reservoir.
• Another version - the collision of the Eurasian plate and Hindustan (which in those eras was an independent continent) led to changes in the surface of the Earth, it was then that the highest Mountain peaks Himalayas and the Baikal depression. However, later this hypothesis was criticized, since scientists were able to prove that by the time the Himalayas were formed, the platforms of the earth's crust, on the border of which the depression is located, had already been formed and colossal changes did not affect them.
• The outpouring of basalt on the surface led to the appearance of vacuum centers and subsidence of the depression.

How do researchers explain the origin of the Baikal basin? It is believed that it is the central part of the Baikal Rift Zone. Under the depression, processes of heating of the bowels take place, the substance of which, spreading, creates horizontal stretching. In turn, they contribute to the formation of new faults and the opening of ancient ones, the lowering of entire blocks and the formation of depressions.

Detailed description of the process

Let us describe in detail the origin of Lake Baikal, which is essentially rift. At the same time, the word "rift" refers to a break in the earth's crust, shaped like a crack or ditch. The Baikal rift is very long, its length is more than 2.5 thousand km, it extends in the central part of Asia from Yakutia to Mongolia. And the lake is located in the central part of the fault, in its deepest area.

The maximum rift depth was calculated: the most deep place lakes (1637 m) + rock fragments, dead animals and plant organisms (approximately 8 km) = 9637 meters.

How did the fracture itself form?

• Under the influence of high temperatures, the earth's crust became thinner and covered with cracks.
• This process was accompanied by earthquakes and the appearance of faults.
• The completion of the process was the appearance of the rift zone.

It is possible that the collision of Hindustan and Eurasia somehow affected the process, corrected it, but could not be the root cause.

The lake continues to form

From almost all sides, the lake basin is surrounded by tectonic depressions:

• Upper Angarsk - in the north;
• Barguzinskaya - in the northeast;
• Onotskaya and Malomorsko-Buguldeiskaya - in the west;
• Khubsugulskaya and Tunkinskaya - in the southwest.

Interestingly, the formation of the reservoir cannot be considered a fully completed process; regular earthquakes continue to modify the relief of Baikal. Minor earthquakes here are a constant phenomenon, but sometimes real disasters occur here:

• In 1862, as a result of a shaking of the earth's crust with a force of about 10 points, an entire piece of land went under water, forming Proval Bay (its depth is about 6 meters).
• In 1959, a 9.5 magnitude earthquake caused the bottom of the lake to sink 20 meters.

The researchers found that the shores of the lake are moving away from one another by about 2 cm annually. This is also due to seismic activity. This fact allowed some scientists to make a bold assumption that Baikal is not a lake, but an ocean at the stage of its inception. In 100 million years, according to this version, Asia will split, a new ocean will appear in place of the reservoir.

Now there are no active volcanoes on the lake, but traces of their activity in past eras continue to be studied by scientists.

Ice influence

Despite tectonic origin Lake Baikal, the features of its relief were seriously influenced by the Ice Age. Evidence that the lake has collided with glaciers can be found by analyzing rock fragments located at its bottom. IN scientific literature they are called bottom moraines. Also traces ice age are bottom sediments, sediments. They allow us to conclude that the thickness of the glaciers moving along the lake was at least 80 meters, but not more than 120 meters.

Scientists have found that the permanent ice cover, most likely, did not fetter the Baikal waters, otherwise life in the lake would be impossible. Meanwhile, researchers managed to discover life forms that formed long before the glaciers:

• Sponges.
• Flatworms.
• amphipods.

They indicate that there was no permanent ice cover on the lake.

Age

The age of Lake Baikal also causes an equal amount of controversy. There are several positions:

• It is traditionally considered that the reservoir is unique: from 25 to 35 million years are attributed to it, which is uncharacteristic for glacial reservoirs, as a rule, they exist for no more than 15 thousand years, after which they become covered with sediments, silt or swamp.
• In 2009, Doctor of Sciences Tatarinov expressed the idea that the deepest parts of the reservoir are no more than 150 thousand years old, and the coastline is much younger - about 8 thousand years old. This hypothesis even has a number of indirect evidence that were obtained during the study, namely the analysis of the activity of bottom mud volcanoes.

There is also a hypothesis that the outlines of the great lake were laid at the end of the Mesozoic period, that is, when the planet acquired modern look and continents were formed. This process took place 60 million years ago. However, a fact was previously indicated that refutes this version.

Water properties

Having considered the origin of Lake Baikal, we learn the properties of its water:

• She is transparent. Objects can be seen even at a distance of 40 meters.
• The color depends on the season: in spring it is blue, in summer and autumn it is densely covered with vegetation, acquiring a blue-green hue.
• Rich in oxygen.
• It contains a very meager amount of dissolved minerals and salts, so it can be used as distilled.
• Very cold, average temperature on the surface in summer time rarely exceeds +9 °C, only in some bays it reaches +15 °C. In the depths the temperature is up to +3...+4 °C.

Ice on the lake appears in the second week of January and stays until the beginning of May, covering the entire reservoir, except for a small area at the source of the Angara (no more than 20 km in length). Interestingly, the ice is also very transparent, it passes the sun's rays through its thickness, which is why plankton actively develops in the depths of the lake.

Bottom Features

We examined the origin of Lake Baikal, now let's see what the specifics of its bottom are. First of all, this is a pronounced relief:

• Shelves and underwater slopes are scattered along the coast.
• There are three basins (Southern, Middle, Northern).
• It is possible to note the presence of underwater ridges (Academic, Selenginsky).
• There are also underwater banks.

These are the features of the bottom of Lake Baikal. Thanks to modern research managed to establish that in this amazing reservoir flooded highest mountains planets whose height is more than 7 km. The thickness of bottom sediments is more than 6 km.

Let's get acquainted with a selection of interesting cognitive facts about the amazing reservoir - the pearl of Siberia:

• In Lake Baikal, whose area is 31,722 km, it is forbidden to catch sturgeon. And the total number of fish species that live here is more than 2 thousand.
• Despite the fact that the reservoir is a lake, not a sea, waves up to 5 m high and even storms are periodically observed here.
• On the coast amazing lake larches grow, the age of which is more than 700 years.
• The length of Lake Baikal is 636 km.
• In the waters of Lake Baikal there are 60-year-old long-lived sturgeons.
• The most non-standard inhabitant of the lake is a transparent fish, almost completely consisting of fatty tissues, the golomyanka is viviparous.

We examined the origin of Lake Baikal and learned that, despite numerous studies, this unusual body of water has not yet revealed all its secrets to humanity.

Baikal - freshwater lake in the south of 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 ​​the lake (mirror area) is 31,500 sq. km.

Baikal is the deepest lake in the world (1620 m). It contains the largest fresh water reserves on earth - 23 thousand cubic km, which is 1/10 of the world's reserve fresh water. A complete change of such a huge amount of water in Baikal takes 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 Angara flows out. Baikal has 27 islands, the largest of which is Olkhon. The lake freezes in January, opens in May.

Baikal lies in a deep tectonic depression and is surrounded by taiga-covered mountain ranges; the area around the lake has a complex, deeply dissected relief. Near Baikal, the band of mountains expands noticeably. mountain ranges stretch here parallel to one another in the direction from the northwest to the southeast and are separated by basin-like depressions, along the bottom of which rivers flow and lakes are located in some places. The height of most of the ridges of Transbaikalia rarely exceeds 1300 - 1800, but most high ridges reach high values. For example, xr. Khamar-Daban (Sokhor peak) - 2304 m, and the Barguzinsky ridge. about 3000 m.

Tectonic movements continue here even now. This is evidenced by frequent earthquakes in the region of the basin, outcrops of hot springs, and, finally, subsidence of significant sections of the coast.

The waters of Baikal have a blue-green color, are distinguished by exceptional purity and transparency, often even greater than in the ocean: you can clearly see stones lying at a depth of 10-15 m and thickets of greenish algae, and a white disk lowered into 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 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. Baikal is located at an altitude of 455 m above sea level. The length of the coastline is about 2000 km. 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. 336 permanent rivers and streams flow into Baikal, while half of the volume of 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 deepest lake in the world, the closest contender for this title, African lake Tanganyika, lags behind by as much as 200 meters. There are 22 islands on Baikal, although, as mentioned above, there is no unanimity on this issue. Most large island— Olkhon.

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.
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. If we assume that the age of Baikal is indeed several tens of millions of years, then this is the oldest lake on Earth.

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 Evenki 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 shore 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.

Baikal water.

Baikal water is unique and amazing, like Baikal itself. It is unusually transparent, pure and saturated with oxygen. In not so ancient times, it was considered healing, with its help, diseases were treated. In spring, the transparency of Baikal water, measured using the Secchi 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 algae bloom begins, the transparency of the water decreases, but in calm weather, the bottom can be seen from a boat at a fairly decent depth. Such a high transparency is due to the fact that Baikal water, due to the activity of living organisms that live in it, is very weakly mineralized and close to distilled. The volume of water in Baikal is about 23 thousand cubic kilometers, which is 20% of the world's fresh water reserves.

Climate.

The climate in Eastern Siberia is sharply continental, but the huge mass of water contained in Baikal and its mountainous surroundings create an unusual microclimate. Baikal works like a big thermal stabilizer - in winter it is warmer in Baikal, and in summer a little cooler than, for example, in Irkutsk, located at a distance of 60 km from the lake. The temperature difference is usually around 10 degrees. A significant contribution to this effect is made by forests growing on almost the entire coast of Lake Baikal.

Baikal's influence is not limited to regulation temperature regime. Due to the fact that evaporation cold water from the surface of the lake is very insignificant, clouds cannot form over Baikal. In addition, the air masses that bring clouds from the land heat up when passing the coastal mountains, and the clouds dissipate. As a result most time over Baikal the sky is clear. This is also evidenced by the numbers: the number of hours of sunshine in the area of ​​Olkhon Island is 2277 hours (for comparison, on the Riga seashore in 1839, in Abastumani (Caucasus) - 1994). You should not think that the sun always shines over the lake - if you are not lucky, then you can run into one or even two weeks of disgusting rainy weather even in the sunny place Baikal - on Olkhon, but this is extremely rare.

The average annual water temperature on the surface of the lake is +4°C. Near the coast in summer the temperature reaches +16-17°C, in shallow bays up to +22-23°C.

Wind and waves.

The wind on Baikal blows almost always. More than thirty local names of winds are known. This does not mean at all that there are so many different winds on Baikal, just that many of them have several names. Peculiarity Baikal winds in that almost all of them almost always blow along the coast and there are not as many shelters from them as we would like.

Prevailing winds: northwest, often called mountain winds, northeast (barguzin and verkhovik, also known as angara), southwest (kultuk), southeast (shelonnik). Max Speed wind, registered on Baikal, 40 m/s. In the literature, there are also large values ​​- up to 60 m / s, but there is no reliable evidence for this.

Where there is wind, there, as you know, there are waves. I note right away that the opposite is not true - the wave can be even with complete calm. Waves on Lake Baikal can reach a height of 4 meters. Sometimes values ​​​​of 5 and even 6 meters are given, but this is most likely an estimate “by eye”, which has a very large error, as a rule, towards overestimation. The height of 4 meters was obtained using instrumental measurements in the open sea. The excitement is strongest in autumn and spring. In the summer on Lake Baikal, strong excitement is rare, and calm often occurs.