Lake Baikal description briefly. Location of Baikal. Reasons to visit Baikal
Baikal is the oldest lake in the world. Its age is about 30 million years. During this period, the formation of Lake Baikal was accompanied by earthquakes, uplifts and subsidence of huge areas of the earth's surface.
Baikal- the deepest of all the lakes of our planet. His maximum depth- 1637 m. In the literature, you can find various values \u200b\u200bof its maximum depth, for example, 1642 m or even 1647 m. deepest point lakes - 1637 meters. She is located south of the cape Izhimei, Olkhon Island.
In 2008 and 2009, researchers on the Mir submersibles re-examined the most deep places Lake Baikal and came to the conclusion that the maximum depth of the lake, nevertheless, remains the same - 1637 m.
In terms of water volume, Baikal ranks first among freshwater lakes peace. It contains 23,000 km3 of water. This is about 20% of the surface fresh waters of the Earth, or about 80% of the surface fresh waters of Russia, excluding glaciers. The reserves of surface fresh waters in Russia make up about 30% of the reserves of the surface fresh waters of the Earth. Surface fresh waters are fresh lakes, reservoirs, rivers and swamps. This list does not include underground fresh water, as well as glaciers, both underground and surface.
in the waters Baikal There are more than 2,500 species and subspecies of animals and more than 1,000 species and varieties of plants.
More than 50% of animal species live only in Lake Baikal and are not found anywhere else. Among them are the smallest epishura crustacean, gammarus benthic crustaceans, freshwater sponges, giant bottom worms, fish - omul, sturgeon, golomyanka, yellowfly, longfly, and of course, the Baikal seal - seal.
The Baikal coast is famous all over the world for its extraordinary beautiful scenery, magnificent bays and coves.
The listed characteristics of Baikal are so amazing and unusual that in 1996 the lake was included in the List of World Heritage Sites. natural heritage UNESCO. Inclusion in the list means that the governments of the countries that own these objects and each person individually must treat them with special care and protect them from pollution and destruction.
The size of Lake Baikal can be compared with the size of some European countries. The area of Baikal is comparable to the area European state Belgium.
Are there lakes on Earth similar to Lake Baikal? Yes, I have. Lake Tanganyika in Africa. Tanganyika is also an ancient body of water, and its shape is very similar to Baikal - just as elongated. Square Tanganyikamore area Baikal. The lake is located in the tropical zone, the water in it is warm. And in warm water more bacteria and algae breed than in the cold waters of Lake Baikal. Therefore, the transparency of the water in the lake is low, and the water is less suitable for drinking.
Lake Upper in the USA and Canada. It is also often compared to Baikal. The area of Lake Superior is larger than the area of Lake Baikal, but it is much smaller and younger. Lake Superior is only 10 thousand years old.
More than others, a lake looks like Baikal Khubsugul. It is located in the Baikal rift zone, it is distinguished by the same purest and clear water, a wide variety of flora and fauna. Khubsugul is several times smaller than Lake Baikal. The volume of Khubsugul's water is 383 km3, which is more than 60 times less than the volume of Baikal's water. Khubsugul and Baikal are connected by a system of rivers.
The Egin-Gol River flows out of Khubsugul, it carries its waters to the Selenga River, and the Selenga flows into Baikal. Therefore, Khubsugul is often called the younger brother of Baikal.
Comparative characteristics of some large lakes of the world
Baikal stretches from southwest to northeast for 636 km. Is it a lot or a little? Compare on the map of Russia: the length of the lake is equal to the distance between the two most famous cities of our Motherland - between Moscow and St. Petersburg.
The maximum width of Lake Baikal is 81 km, it is located opposite the Barguzin Bay, the minimum width is 27 km - at the confluence of the Selenga River.
Length coastline lakes - 2000 km. It will take almost 4.5 months to go around Baikal. It will be a very difficult journey, as in some places impenetrable rocks come close to the shore, and they will have to be bypassed.
The main characteristics of Lake Baikal
cartographic basis. Map of Lake Baikal.
Atlas “Lake Baikal. Past. The present. Future". FSUE "VostSib AGP", 2005.
Baikal is filled with waters of more than 300 rivers, rivers and streams. In the literature, you can find data, for example, that 544 tributaries flow into Baikal, or 1123 tributaries. These results were obtained not by counting the tributaries themselves, but by the mountain gorges depicted on geographical maps. And along the ravines flow both permanent and temporary watercourses. In dry years, they can dry up, in years with heavy rains they can be filled with water again. Therefore, the number of tributaries is not constant.
- the deepest lake. Depth of Baikal about 1700 meters. In the world only one lake can be compared to depth with Lake Baikal. This lake Tanganyika in East Africa. Its depth is about 1400 meters. Depth of Lake Baikal comparable to the depth of the Northern Arctic Ocean, the average depth of which is 1220 meters.
Baikal - most big lake in Asia. Water surface area Lake Baikal over 30 thousand square kilometers.
Lake Baikal water is its main value. Lake Baikal – most large reservoir of fresh water in the world. Baikal contains approximately a fifth of the world's reserves.
The deepest bay Lake Baikal- Barguzinsky. The depth of the Barguzinsky Bay is almost 1300 meters.
Most big bay Lake Baikal- Barguzinsky. The area of the bay is 725 square kilometers.
The youngest bay of Baikal- Fail Bay. Proval Bay was formed after a powerful earthquake in 1862. Part of the Selenga delta with an area of about 200 square kilometers has gone under water. This earthquake also caused the formation the youngest cape of Baikal- Cape Oblom.
Most big Island Lake Baikal- Olkhon. The island is located in the middle Baikal and divides lake to the Big and Small seas. The island is 71 kilometers long and 12 kilometers wide.
On Cape Kotelnikovsky is the most. Water temperature in mineral springs Cape Kotelnikovsky plus 81 degrees Celsius.
The basin of Lake Baikal – deepest mainland depression. Bottom of Lake Baikal lies below the level of the world ocean by about 1200 meters.
The largest influx Lake Baikal the Selenga river. The Selenga has a length of about 1000 kilometers. About half of all the water that enters lake, brings precisely the Selenga.
Most large peninsula Lake Baikal- Holy Nose. The peninsula measures about 50 kilometers long and about 20 kilometers wide.
Depth of Lake Baikal
Basin of Baikal consists of three rather separate parts. The middle basin is the deepest. It is here near the eastern coast of Olkhon Island depth of Lake Baikal reaches almost 1700 meters. Depth southern basin Lake Baikal approximately 1432 meters. The largest measured depth northern part Lake Baikal 890 meters. Medium lake depth also very large - more than 700 meters. The biggest depth Small Sea - near the northwestern coast of Olkhon Island. It is approximately equal to 250 meters. The smallest depth in the open Baikal- about 30 meters. Northern and middle basins Lake Baikal separates the underwater Academic Ridge. lake depth in these places about 260 meters. Between the middle and southern basins Lake Baikal the Selenga bridge is located. The smallest depth here 360 meters.
Where is Baikal located?
Baikal is located in the middle of Asia in the south of Eastern Siberia between the Republic of Buryatia and the Irkutsk region Russian Federation. Close to lakes the cities of Irkutsk and Ulan-Ude are located.
Length, length, width of Baikal
Lake Baikal is a fracture in the earth's crust filled with water. water in lake carry several hundred large and small streams. Lake Baikal stretched from south to northeast: length or length of Baikal about 640 kilometers. The largest width of Baikal 80 kilometers. Small earthquakes constantly occur in the vicinity of the lake. Occasionally there are big ones. coast Baikal moving away from each other at a rate of 2 centimeters per year - Baikal is growing!
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- the greatest on our planet. It is inextricably linked with Russia and is one of its symbols. Located near the center of Asia, Lake Baikal is known far beyond this continent.
The Baikal basin was formed by tectonic processes: the lake lies in deep depression surrounded on all sides by mountain ranges. is the oldest lake in the world. He is about 25 million years old. During all this time, the shores of Baikal diverged from average speed 2 cm per year, and in the distant future, Baikal may turn into real ocean. Baikal is the deepest lake on Earth. Its maximum depth is 1620 meters. This allows Baikal, with a relatively small surface area (31,500 km 2 .), to contain 20% of the world's fresh water reserves: 23 thousand km 3. About the same amount contain all five Great Lakes North America together taken - Upper, Michigan, Erie, Ontario and Huron. In order to fill the empty basin of Baikal, it would take the volume of water that all the rivers of the planet bring into the world ocean in 300 days. And another “Great Giant”, the Amazon River, would need to feed Baikal for four years to do this.
336 rivers flow into the lake, but the main role in the water balance of the lake is played by Selenga, contributing to the basin 50% of the annual inflow of water. At the same time, the lake gives life to only one river - Angara, on which the dam of the Irkutsk hydroelectric power station was built in 1959, which raised the water level in Baikal by a meter. It is on the Angara, which is called the “daughter of Baikal”, that the largest Bratskoye reservoir on our planet with a volume of 169.3 km 3 was created. The water in Baikal is dark blue and so transparent that in June, when transparency reaches its maximum, one can observe forty-meter depths with the naked eye. It is curious that the water in the lake is fresher than the water of the rivers flowing into it, and its mineralization decreases with depth. Scientists have put forward a hypothesis about the existence of a permanent powerful superfresh source at the bottom of Lake Baikal. Until it is proven or disproven.
Water exchange of Lake Baikal
Speaking of exceptional purity, one of its inhabitants should be mentioned, thanks to which water from the lake can be safely drunk without any additional purification. This is a tiny crab epishura, which is one of the endemics of the lake (that is, it is not found anywhere except Baikal). It is this crustacean, repeatedly passing the waters of the lake through itself, and cleans them. Epishura is not the only Baikal endemic. Two thirds of the flora and fauna of the lake live only in Baikal. The most famous are the Baikal seal, the Baikal omul, the Baikal seal, some species of gobies, as well as the golomyanka viviparous fish. In total, 2.6 thousand species and varieties of plants and animals live in the lake.
Ecology of Lake Baikal
In the 20th century, the unique world of the lake faced a problem that threatened the possibility of the continued existence of nature. In the early 60s of the XX century, the construction of the Baikal Pulp and Paper Mill (PPM) began on the southern shore of the lake. In this regard, a discussion immediately unfolded. Scientific expeditions were sent to the Baikal region, the purpose of which was to find out how the environmentally negative activity of the plant affects unique nature lakes. Newspapers actively discussed the possibility of creating "clean" technologies for pulp and paper production. The problem was reflected even in art: in 1970, director S. A. Gerasimov shot the film “ At a lake", whose heroes are looking for a compromise between the need to create a plant and the desire to preserve Baikal. Despite harsh criticism, the pulp and paper mill was built and put into operation in 1966. Its effluents, as well as those of the pulp and paper mill (PPM) on the Selenga River in in large numbers contain toxic phenols, chlorides, sulfates and particulate matter.
Baikal Pulp and Paper Mill
As a result, back in 1994, in the area of the Baikal pulp and paper mill, the water pollution zone extended to 10 km2, and the area of the polluted bottom area was 70 km2. The Selenga River, which plays an important role in the water balance of the lake, also brings the runoff of the city of Ulan-Ude into its basin. An increased concentration of phenols was found in its waters, and the content of oil products exceeds the MPC (maximum permissible concentration) by 3–15 times. The forces of the lake are still coping with the misfortunes that have fallen, however, the resources of Baikal are not unlimited, and if nothing is done, they will run out sooner or later. Then the life of a listed lake World Heritage UNESCO will be in danger, and it is possible that, many years later, our descendants, having gone to the water surface
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 - a large 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 shore is often hidden somewhere in the haze... At the same time, the Small Sea and the Big Sea are distinguished. The Small Sea is what 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, 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 and 90% of Russian fresh water reserves. Every year, the Baikal ecosystem reproduces about 60 cubic kilometers of clear, oxygenated water.
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 indeed a 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 also taking place in present time, which is manifested in the increased seismicity of the Baikal region.
Climate in the area of Lake Baikal.
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 70 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.
The influence of Lake Baikal is not limited to the regulation of the temperature regime. Due to the fact that the evaporation of cold water from the surface of the lake is very small, 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, the sky over Baikal is clear most of the time. This is also evidenced by the numbers: the number of hours of sunshine in the region of Olkhon Island is 2277 hours (for comparison - on the Riga seashore 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 get 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 on Baikal.
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). Maximum wind speed, registered on Baikal, 40 m/s. Large values are also found in the literature - 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 large error, as a rule, in the direction of 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.
Ichthyofauna of Baikal.
Depending on the habitat conditions, fish can be divided into several groups. Sturgeon, pike, burbot, ide, roach, dace, perch, minnow occupy coastal shallow waters and river deltas in Baikal. Fish of Siberian mountain rivers: grayling, taimen, lenok inhabit small tributaries of the lake and its coastal zone. Omul, since ancient times considered a symbol of Baikal, inhabits its open and coastal part, whitefish, another well-known inhabitant of Baikal, inhabits only the coastal part.
The most remarkable group of Baikal fish are gobies, of which there are 25 species. Most Interest of them are golomyanka. This miracle of Baikal is not found anywhere else in the world. Golomyanka is unusually beautiful, shimmers in the light blue and pink, and if it is left in the sun it will melt, leaving only bones and a greasy stain. She is the main and most numerous inhabitant of Baikal, but rarely gets into the nets of fishermen. Her only enemy is the seal, for which she is the main food.
In order to preserve rare and endangered animals, the strictest and complete ban on hunting, the maximum preservation of the habitat, the creation of special nurseries, national parks, nature reserves and sanctuaries
Baikal has an elongated crescent shape. His extreme points lie between 51°29" (st. Murino) and 55°46" (mouth of the Kichera River) north latitude and between 103°44" (st. Kultuk) and 109°51" (Dagar Bay) east longitude.
The shortest line passing through the area of the lake and connecting the most remote points of its shores, i.e. the length of the lake, equal to 636 km, the largest width of Baikal, equal to 79.4 km, is located between Ust-Barguzin and Onguren; the smallest, different 25 km, is located opposite the delta of the river. Selengi.
The area from which rivers currently collect water and bring it into Baikal, or its so-called catchment area, is 557,000 square meters. km *) . It is distributed in relation to the area of the lake itself very unevenly (see the map of the basin). Along the entire western shore, the border of this area runs just a few kilometers from the lake shore. It is limited almost everywhere by the watershed of the mountains visible from the lake.
*) According to Yu.M. Shokalsky, the basin of Lake Baikal reaches 582,570 sq. km. - Approx. ed.
The basin of the Lena River approaches this watershed along the entire length of northern Baikal, and the Lena itself originates 7 km from the shore of Lake Baikal near Cape Pokoiniki. The catchment area of Baikal to the south and southwest of the lake towards the Selenga River basin is most widespread. The basin of this river, equal to 464,940 sq. km, is 83.4% of the total catchment area of Lake Baikal. The next largest basin is the Barguzin River, whose basin is 20,025 sq. km and is 3.5% of the total catchment area of Lake Baikal. The share of all other tributaries of Baikal accounts for a catchment area of 72,035 sq. km, equal to 13.1% of the total catchment area of the lake.
Lake Baikal itself is located in a narrow basin, bordered by mountain ranges, spurs of the Sayan, cut in a number of places by relatively narrow valleys, along which its tributaries flow into the lake.
In the south, along its eastern shores, snow-covered peaks of the Khamar-Daban ridge stretch almost all year round with the highest heights up to 2000 m above sea level. This is exactly the chain of mountains that is visible to anyone passing along the shores of Lake Baikal along railway. These mountains are especially clearly visible on the stretch between st. Baikal and st. Kultuk. The Pribaikalsky Range adjoins the western shores of southern Baikal. Its height almost along its entire length from Kultuk to the Small Sea does not exceed 1300-1200 m above sea level, but these mountains stand on the very shore of Lake Baikal.
Starting from the Small Sea and up to the northernmost tip of the western shores of Lake Baikal, the Baikal mountain range, gradually rising to the north from Cape Rytoy to Cape Kotelnikovsky. In this section, Mount Karpinsky reaches greatest height at 2176 m, Mount Blue - 2168 m, etc. Almost the entire length of the peaks of the Baikal Range is covered with snow that does not melt even in the middle of summer, and in many places traces of glaciers that descended from them until recently are visible.
This ridge is crossed by a series of deeply incised valleys along which mountain streams stretch. In terms of their picturesqueness, the eastern shores of the northern part of the lake are one of the most wonderful places on Baikal. To the eastern shores, starting from the Chivyrkuisky Bay and to the northernmost tip of the lake, another ridge approaches - the Barguzinsky, reaching a considerable height - up to 2700 m. This ridge, however, is located at some distance from the shores, and relatively low foothills adjoin directly to the latter, in some places forming picturesque cliffs, and on the predominant part of the coast, gently descending to the waters of the lake.
The interval of the eastern shore of the lake between the Selenga and the Barguzin Bay is bordered by the Ulan-Burgasy ridge, which has a height of 1400-1500 m near Baikal.
The most pronounced bend of the coastline of Lake Baikal is the Svyatoy Nos peninsula, located between the two largest bays on Baikal - Barguzinsky and Chivyrkuisky.
This peninsula in the form of a massive block of stone, reaching a height of 1684 m, rises above Baikal, falling to the water with steep rocky cliffs. However, towards the mainland, it falls more gently and then passes into a narrow and swampy isthmus, merging with a vast lowland adjacent to the river valley. Barguzin. There is no doubt that until recently the Svyatoy Nos Peninsula was an island, and the waters of the Chivyrkuisky and Barguzinsky bays formed one vast strait, subsequently filled with drifts from the river. Barguzin.
Baikal has 19 permanent islands, the largest of them is Olkhon. It has a length of 71.7 km and an area of 729.4 sq. km. Olkhon Island, - separated from the continent by a strait less than a kilometer wide, called "Olkhon Gates", elongated in a northeasterly direction, is a mountain range, with the highest point - Mount Izhimey, reaching a height of 1300 m and abruptly breaking off to the east shore. The northern part of the island is wooded, while the southern part is completely devoid of tree vegetation and is covered with meadows with traces of steppe vegetation that was once, apparently, widespread here.
The shores of Olkhon facing the Small Sea are subjected to very strong destruction by the surf. Interesting both in its position and in its picturesqueness is the group of the Ushkany Islands, located opposite the Svyatoy Nos peninsula in the middle part of the lake. This group consists of four islands, of which Big Ushkany Island has an area of 9.41 sq. km, and the remaining three islands (Thin, Round and Long) do not exceed half a square kilometer. The large Ushkany Island reaches a height of 150 m, while the small ones are only a few meters above the average water level of Lake Baikal. All of them are rocky, with banks composed mainly of limestone and covered with dense forest. These islands are greatly destroyed and, as it were, cut off by the surf.
The time is not far off when the small Ushkany Islands will disappear under the surface of the waters of Lake Baikal.
The remaining islands on Baikal are all located near its shores, four of them are in the Chivyrkuisky Bay (Bol. and Small. Kyltygey, Elena and Baklany), six in the Small Sea (Khubyn, Zamugoy, Toinik, Ugungoy, Kharansa, Izokhoy, etc.) and the rest - in close proximity to the shores of other parts of Baikal, such as Listvenichny, Boguchansky, Baklany (near Peschanaya Bay), etc.
All islands have a total area of 742.22 sq. km, and most of them are large capes, separated from the continent under the influence of the destructive force of the surf. In addition, there are also several low sandy islands on Baikal, which in high water are completely hidden under water and protrude above the surface only when the water is low. Such are the islands elongated in the form of narrow strips separating Proval Bay from Baikal (Chayachi Islands, Sakhalin), such are the islands separating from open Baikal Angarsk litter - the so-called Yarki. The islands separating the Istoksky Sor from the open Baikal belong to the same type.
The bays and inlets, which are so important for the anchorage of small vessels, are a relatively rare phenomenon on Baikal, moreover, they are very unevenly distributed along the coast.
The largest bays, Chivyrkuisky and Barguzinsky, which we have already mentioned above, are formed by the Svyatoy Nos peninsula protruding from the lake. Almost a bay is the so-called Small Sea, separated from open Baikal by Olkhon Island and Proval Bay, to the north of the Selenga Delta.
Peschanaya and Babushka bays on the western shore of southern Baikal are famous for their picturesqueness. Further, a peculiar group of bays, or rather lagoons, bearing the name “sors” on Baikal, are its former bays separated from the open lake by narrow sandy spits. Such are the Posolsky and Istoksky sors, separated from Baikal by narrow strips of land washed by the action of the surf, such is the Angarsky sor in the very north and Rangatui in the depths of the Chivyrkuisky Bay. All of them are separated from Baikal by narrow strips of sediment, in the form sandbars, in high water sometimes completely hiding under the surface of the lake.
Except for these, almost separated from Baikal by its deposits, large bays, then all other bends of its shore depend to a large extent on the direction of the coastline of Baikal, since the sinuosity of its shores depends on whether the shore is directed along or across the dominant direction of the mountain ranges that make up the shores.
Those sections of the Baikal coast that are directed across the main direction of the mountain ranges that limit its basin are characterized by significant indentation, such as, for example, the Olkhon Gates or South coast Barguzinsky Bay. Those sections of the coast, which in their direction coincide with the direction of the mountain ranges that limit the Baikal basin in this area, are characterized, on the contrary, by exceptional straightness, disturbed only by secondary accumulations of coastal sediments or the eroding effect of the surf. This is the entire section of the western shore of Lake Baikal from the mouth of the river. Sarma to Cape Kotelnikovsky, such is the area that limits the Svyatoy Nos peninsula from the west, and many others.
In many areas, the shore of Lake Baikal is completely straight for many kilometers, and almost sheer cliffs, many meters high, break into the water very often. Particularly characteristic in this regard is the section between Sosnovka and the entrance to the Chivyrkuisky Bay on east coast middle Baikal or a section from Onguren to Cape Kocherikovsky on the western shore of middle Baikal.
According to the distribution of depths or the topography of the bottom, Baikal can be divided into three main deep depressions. The first of them - southern, occupies the entire southern Baikal to the confluence of the river. Selenga. The greatest depth of this depression is 1473 m, while the average depth is 810 m. The depression of southern Baikal is characterized by an exceptionally steep bottom slope near the western and southwestern shores and a relatively gentle slope near the opposite slopes.
Lacustrine deposits at the bottom of the southern depression have not completely smoothed out the features of the original relief, at the bottom of which there are a number of hollows and irregularities adjoining the Trans-Baikal coast and elongated in a northeasterly direction. These underwater ridges are especially pronounced in the part of the depression adjacent to the delta of the river. Selenga, and hide under its deposits. One of these ridges stands out so much that it forms in the middle of the width of Baikal on the line between the village. Goloustny and s. Posolsky shallow water, where depths of 94 m have been discovered, and the depths in this shallow water have not yet been sufficiently explored and it cannot be vouched for that even smaller depths will not be found there. This shallow water is, in all probability, a remnant of what has been noted here on old maps Stolbovoy Island, partly destroyed by the waters of Baikal, partly submerged under its surface.
On the bridge separating the southern deep basin of Baikal from its middle basin, the depth does not exceed 428 m, and this bridge basically reflects the structure of the bedrock. This view is supported by the presence of a longitudinal ridge, elongated in front of the Selenga delta, extending far both in the southwestern and northeastern directions and is known from local residents called "manes". In its part adjacent to the Selenga, this lintel is gradually and significantly modified by the offsets of the Selenga.
To the east of the ridge directed to the northeast, approximately opposite the channel of the Selenga delta, called Kolpinnaya, there is a deepening of the bottom, reaching 400 m and locally called the "deep". A legend is connected with this abyss that in this place in the bottom of Baikal there is a hole through which Baikal connects either with Lake Kosogol or with the North Polar Sea. The emergence of this legend was facilitated by the fact that in the region of the depression there is a local whirlpool, which is well observed on quiet days, when all objects floating on the surface receive rotational motion. This whirlpool, which gives the impression that water is drawn into the hole below, is caused by the meeting of currents in two directions, which mix the surface layers of water to a depth of about 25 m.
The middle deep basin of Baikal occupies the entire space between the barrier against the Selenga and the line connecting the northern tip of Olkhon Island through the Ushkany Islands with Cape Valukan on the eastern shore of Lake Baikal. In this depression are the greatest depths of Baikal, reaching 1741 m. This depth is located at a distance of 10 km from Cape Ukhan on Olkhon. The average depth of the basin reaches 803 m. The area occupied by depths over 1500 m, which are not found in the other two deep basins of Baikal, is 2098 sq. km. km. The bottom has a particularly steep drop near the eastern shores of Olkhon Island, as well as to the east of the Ushkany Islands, where in some areas of the bottom the slope angle reaches over 80 °.
The bottom sections adjacent to the eastern coast of the depression are more gentle, and depths of 100 m in some places are here several kilometers from the coast.
The Barguzinsky Bay, which is part of the middle basin, has a very complex bottom topography. It is divided into two depressions by an underwater ridge. In the part of the bay adjacent to the southern head of the Svyatoi Nos peninsula, depths of more than 1300 m enter, which go far into its northern part. The relief of the bottom of the entire eastern part of the bay is influenced by the drifts of the river. Barguzin, which covered the bedrock topography with a thick layer of sediments.
The depression of middle Baikal is separated from the northern depression by an underwater ridge, open station in 1932 and named Academic.
This ridge, on which the depths do not exceed 400 m, stretches from the northern tip of Olkhon Island to the Ushkany Islands and further, less pronounced, to the north to Cape Valukan. Thus, the Ushkany Islands themselves are only protruding above the surface northern part Academic Ridge. This ridge has slopes that descend very steeply to the southeast towards the depression of middle Baikal, and gently to the northwest towards northern basin, i.e. retains the same features as the profiles of Olkhon Island and Bolshoi Ushkany Island.
The northern deep basin of Baikal occupies the entire space located north of the Akademichesky Range and includes the Small Sea. This depression has the greatest depth of only 988 m, its average depth is 564 m. south end Small Sea to the Kotelnikovsky Cape area. In the northern depression near the western shores, the bottom slopes more steeply into the depths than near the eastern shores, where there are significant shallow waters.
Most of the surface of the bottom of Lake Baikal at depths of more than 100 m is covered with thick deposits of silt, which mainly consists of countless shells, dead and fallen to the bottom of algae that lived in the upper layers of water. Only in a few places, like the Akademichesky Ridge, does the bottom of Baikal consist of bedrock; there are also areas of the bottom where great depths ah you can find rounded boulders and pebbles, obviously, these are the flooded channels of ancient rivers, not covered with silt deposits due to the bottom currents there.
As for the shallow depths of Baikal, many consist of vast areas, especially those adjacent to river deltas, of sand or sand mixed with silt. Even closer to the coast, the bottom is covered mainly with stones and more or less large pebbles. Only in a few areas the bottom to the very shores is composed of sand. Such areas have great importance as suitable for seine fishing.
Not always, however, Baikal had those character traits bottom topography and the form of its outlines that it currently possesses. There is reason to assert the opposite, namely, that Baikal in its present form was formed, from a geological point of view, relatively recently - at the end of the Tertiary or even at the beginning of the so-called Quaternary time. By this time, according to modern views of geologists, the formation of great depths of Baikal, as well as the formation of those mountain ranges that border the lake, belongs. There is little information about what the reservoir that was on the site of Baikal before that time was.
Apparently, it was a complex system of lakes, interconnected by straits and occupying a larger territory than modern Baikal. There is reason to believe that this multi-lake area extended to Transbaikalia, Mongolia, and possibly Manchuria and Northern China.
Thus, Baikal in its current state is, to a certain extent, a remnant of water bodies that once occupied a vast area and repeatedly underwent significant changes. How this could affect the composition of the fauna and flora of Baikal, we will consider below, in the corresponding chapter.
During ice age when powerful glaciers covered some parts of Siberia large spaces, there was no continuous glaciation in the Baikal region, and glaciers descended to the shores of Baikal only in some places. Heaps of stones and sand, brought by glaciers and called moraines, in northern Baikal in many places descend from the adjacent mountains to Baikal itself, but it can be argued that this ice has never completely covered the surface of Baikal.
The moraines left after the ice age had a significant impact on the formation of the shores of Northern Baikal. Some capes in the north of Baikal are made of moraine materials, such as, for example, Cape Bolsodey. On the eastern shore of Northern Baikal, where many capes are also made of moraine material, they were subjected to severe destruction by the surf. Smaller boulders and loose material were washed away by the waves, and large boulders, preserved in the area as dangerous pitfalls for navigation, are the remains of moraines that were in these places and indicate their much greater distribution in the past than is the case now.
Geologists have made different assumptions about how the Baikal basin with its vast depths was formed in its modern form.
During the eighteenth and first half of the nineteenth centuries, geologists believed that Baikal was a deep sinkhole in the earth's crust, resulting from major disaster that took place in this area of the mainland. I.D. Chersky significantly changed these ideas. He considered Baikal not a failure, but a very ancient reservoir, preserved from the time of the Silurian Sea and gradually deepened due to the slow and smooth bowing of the earth's crust.
Later acad. V.A. Obruchev returned to the old ideas about the failure and explains the formation of the modern depths of Baikal by subsidence of the bottom of the graben, which this lake is. This subsidence occurred simultaneously with the uplift, which formed a mountainous country on the coast of Lake Baikal, and apparently continues to this day.
There are other geologists who also associate the formation of Baikal with the arched uplift of the Baikal region and subsidence - the collapse of the central part of this arch, but the time of this uplift, in their opinion, refers to the second half of the Quaternary period, i.e. to the time of the existence of primitive man.
Finally, according to the latest views of E.V. Pavlovsky, the Baikal depressions and the ridges separating them are the so-called synclines and anticlines, complicated by faults and developed gradually over many geological epochs, against the background of a general arched uplift of the Stanovoi ridge.
Finally, according to the views of N.V. Dumitrashko, Baikal is a complex system of three basins. The southern one arose during the Upper Jurassic, the middle one - in the Tertiary time, the northern one - at the border of the Tertiary and Quaternary time. The hollows and the ridges surrounding them are blocks into which the Baikal region was divided during the last epochs of mountain building. The slumped boulders turned into depressions, the rising ones turned into ridges. We have a range of evidence that the formation Baikal basin continues to this day, and that the bottom of the basin at the same time continues to sink, and its edges in the form of limiting, Baikal depressions of mountain ranges rise.
Signs of the lowering of the coast, villages. Ust-Barguzin in 1932. Photo by G.Yu. Vereshchagin
The subsidence of the shores of Baikal is especially pronounced in places where the basin continues beyond its shores, such as, for example, to the west of the area between Kultuk and Slyudyanka, in the Barguzin Bay, in the area between the Kichera and Upper Angara rivers, as well as on the far protruding basins of Baikal, the delta of the river. Selenga. In all these places, not only are there features of the coastline, which indicate the gradual sinking of the coast under the lake level, but there are also those confirming this. historical facts. So the village of Ust-Barguzin has already changed its place twice, moving away from the shore of Lake Baikal, as the waters of the lake flood the place of its former location. This village is in a semi-flooded state at the present time. A similar phenomenon is observed in the village located at the mouth of the river. Kichery (Nizhnangarsk), where once was the center of the entire district, and now only a small number of houses remain. In the Selenga delta, the lowering of the terrain is expressed in the gradual swamping of the delta's meadows and the transformation into a swamp of once-dry mowings and even fields.
But the most significant is the lowering of part of the coast in the area of the river. Selenga in December 1861, which led to the formation of Proval Bay. Then the northern part of the river delta disappeared under the waters of Lake Baikal. Selenga, the so-called Tsagan steppe with all the Buryat uluses, hayfields and other lands, with total area about 190 sq. km. This was preceded by an earthquake, while a strong vertical impact was felt, from which the soil on the steppe swelled with mounds and sand, clay and water were thrown out of the wide cracks formed. The steppe was flooded with water, which spouted fountains, more than two meters high. And the next day, the water of Baikal flooded the entire descended space to the Bortogoi steppe. According to eyewitnesses, the water came from the lake like a wall. In place of the steppe, Proval Bay is currently spreading with depths of up to three meters.
The secondary redistribution of sediments along the shores leads to a number of changes in the nature of the Baikal coastline, of which we will only point out the most important ones. Thus, the accumulation of these sediments in bays and other bends of the coast leads to their gradual straightening and the formation of shallow, gently descending to the water's edge coasts, composed of sand or small pebbles, which are usually good non-aqueous tones.
The movement of sediment along the coast leads to other phenomena: for example, islands located near the coast are gradually attached to the coast by forming a bridge made of sediment connecting them to the coast. The largest of these bridges on Baikal connects, as already noted, the former rocky island of Svyatoy Nos with the continent, turning it into a peninsula. Typical dams made of sediments are observed on some capes of the Small Sea, such as Kurminsky, which was also once an island and only secondarily, by sediments, is attached to the coast. In the same way, some capes in the Chivyrkuisky Bay are attached to the coast, for example, Cape Monakhov, Cape Katun, etc.
The advancing coastal shaft near the mouth of the river. Yaksakan ( East Coast northern Baikal). Photo by L.N. Tyulina
The movement of sediments along the coast also leads to the lacing of its bays from the lake. It is this process that caused the formation of its so-called sors on Baikal. Once it was just the bends of the coast - bays. Away from these bays along the coast, under the influence of the prevailing direction of the surf, the movement of sediments, which, having reached the bay, was deposited on its bottom in a direction that is a continuation of the general direction of the coast in this area. Thus arose narrow, elongated in the form of stripes sand islands, by which the litter is gradually separated from Baikal. In some cases, such bridges have already led to the almost complete separation of bays from the lake, such as, for example, Posolsky sor. In other cases, this process is not completed, such as, for example, the Istoksky sor, or it is just beginning, which takes place in Proval Bay.
In the cases prevailing on Lake Baikal, coastal sediments are weakly accumulated near its shores, and as a result, the shores themselves are exposed to the destructive action of the surf. Some parts of the coast are literally gnawed away by the surf. Up to a height of 5 meters or more, the rocks are destroyed, representing cliffs with an uneven, porous surface, and in many places niches and caves are carved into the rocks by the surf.
The destruction is especially strong on the shore of the island facing the Small Sea. Olkhon and, in particular, on the capes of this coast, as well as on the capes of the Olkhon Gate Strait.
The surf can also lead to the complete destruction of the islands, as if cutting them near the water's edge. It is in this state, very close to complete destruction, that the Small Ushkany Islands are located, of which the long island is currently only a few meters wide.
Completely cut off by the surf of Lake Baikal, apparently, is the island of Stolbovoy, which was once in the middle of Lake Baikal between Goloustnoye and Posolsky and marked on old maps, and now its trace has been preserved only in the form of a shoal in this place.
The surf leads to the separation of capes from the continent and their transformation into islands. This is observed in the Small Sea, where the islands of Kharansa and Edor arose in this way.
Enormous waves, causing a strong surf, as well as the roughness of the lake, in which this excitement is repeated very often, cause an exceptionally strong influence of the surf on the shores and leads both to their destruction and to the movement of sediments and the formation of shore sections washed by the lake. Baikal is a classic place for studying the work of the lake on its shores, which is far from being appreciated in this regard to the proper degree.
