The modern tectonic structure of the Caucasus was formed about 25 million years ago during the Tertiary period. Today, these are areas in which volcanoes are periodically activated due to internal geological processes. They are the same age as the Alps and consist of gneiss and granite.
General information
The Caucasus is a vast deformation zone where the Arabian and Eurasian plates collided. The mountains here were formed due to the movement of continents. Every year, the Arabian Plate, pressed by the African Plate, moves north by several centimeters.
For this reason, destructive earthquakes are frequent in the region, due to which the Caucasus suffers. The tectonic structure is slowly changing, causing tremors to occur that destroy human infrastructure on the surface of the earth. For example, in 1988, a colossal tragedy occurred in Armenia, in which 20 thousand people died, and another 500 thousand lost their homes.
Breeds
The strata plains, sloping to the north, are formed from Paleozoic crushed rocks. They are riddled with veins of acidic magma and look like giant folds. They consist of granite, quartzite and slate. In the valley of the Alikonovka River near Kislovodsk you can find the most ancient rocks of the ridge.
The tectonic structure here brought to the surface red and pink granites, the age of which is estimated at 220-230 million years. During the Mesozoic era, they were destroyed, which is why they formed a layer of crust, the thickness of which is about 50 meters. Its composition includes quartz and mica.
Here you can also find geodes - geological formations in the form of closed cavities in sedimentary rocks. Mineral substance is deposited inside, which forms symmetrical layers. Moreover, the inner surface of such cavities can be formed from crystals, kidney-shaped crust, deposits and other mineral aggregates. Caucasian geodes sometimes contain the rare material celestine, a mineral of a transparent blue hue.
Sediments
But on the southern slopes you can find sedimentary rocks formed during the existence of Jurassic and Cretaceous reservoirs. Previously, there were seas here, but now there are brown and yellow limestones, dolomites and red ferruginous sandstones.
The structure of the Caucasus Mountains also includes deposits of various stones, for example, travertine, which appeared after the evaporation of mineral waters. In such rocks you can see clear traces of leaves and branches that existed millions of years ago.
Structure
The tectonic structure of the Caucasus divides this mountain system into two ridges. One of them is called Big, and the other is called Small. Between them lie plains.
The Greater Caucasus is also known as the Northern Caucasus (this term is especially often used in Russia to refer to the local republics within the federation). To the south of it there is a watershed ridge. Further still lies the region known as Transcaucasia. It most often includes the territory of three states: Georgia, Armenia and Azerbaijan.
Geologists also identify two more important regions: the Scythian platform and the intermountain zone.
Greater Caucasus
The Greater Caucasus extends for 1,100 kilometers in the direction from northwest to southeast. Its natural borders are the Black and Caspian Seas. Approximate extreme points include Anapa in the Krasnodar Territory and Mount Ilkhydag near Baku, Azerbaijan.
This mountain system is divided into several parts. The watershed ridge (or Main Caucasian) has a height of 3 to 5 thousand meters. The highest peaks in Europe are located here. The tectonic structure of the Caucasus has created majestic landscapes.
The mountain structure of this massif consists of a crystalline foundation of ancient age - this is the Main Range. Its core is surrounded by a young cover consisting of new rocks. It is they who form what in science is called “lift wings.” There are only two of them - northern and southern.
The first is composed of folded sediment. They are crushed by rocks of Mesozoic and Cenozoic age. The young wing is formed from thick sediments, which are the cause of great geological stress in this region. The structure is such that the rocks remain crumpled into complex and numerous folds. The nappes and thrusts broke them into several parts. The wings give scientists information from which it follows that the main mountain masses of the ridge are moving south. Old sediments are covered by young ones and are hidden under the waters of the Azov, Black and Caspian seas.
In the Paleozoic era, the northern part of the Caucasus was the outskirts where the continent and the Paleotethys ocean came into contact. At first it was a quiet region without volcanic or geological activity of the type that now exists in the Atlantic. However, over time, the situation changed, internal processes made themselves felt.
Lesser Caucasus
The second significant ridge of the general chain. The Caucasus ends here. The tectonic structure of this region consists of ridges, highlands of volcanic origin, as well as plateaus. One of the differences from the Greater Caucasus is the absence of a single massif. On the contrary, many small ridges intersect here, resulting in the formation of a large number of valleys. There are no significant glaciers or majestic mountains here. The reason is that tectonically this region is very young. High peaks have not yet formed.
The moving parts of the Alpine-Himalayan belt collide here, which is why the Lesser Caucasus has a much more complex geological structure, unlike its “big brother”. To the south another plate begins. While the North Caucasus has almost no volcanic arcs or troughs, there are an order of magnitude more of them here.
Geological history of the region
The geological history of the Lesser Caucasus can be described by several features, which corresponded to all the processes occurring here over millions of years.
Previously, this place was occupied by a tectonic suture and the huge Tethys Ocean. The local volcanic activity in the depths of the waters was the most powerful on Earth during the Mesozoic era. The ocean was surrounded by several microcontinents. Over time, they finally surrounded this pool, dividing it into several parts. At the turn of 85 million years ago, a single continent was formed, which was subjected to tectonic changes many times.
Gondwana, which moved from the north, caused the vast oceanic spaces to shrink to small sizes. Underwater volcanoes and the former boundaries of miniature continents also disappeared.
Scythian platform
An important part of the ridge is the Scythian young platform. It consists of two floors. The lower one is the foundation, made up of rocks of Paleozoic origin (230-430 million years old). The top floor is called the cover. It is younger and consists of Mesozoic rocks (65-250 million years old). These are marine sediments made of clay and carbonate. In the middle part of the Ciscaucasia, which corresponds to the Stavropol Territory, the foundation rises and further to the east and west it begins to sink.
The Scythian platform on its southern borders ends in several troughs - Kuban, Terek, Kusaro-Divichensky. Here, 40 million years ago, rocks were destroyed, which resulted in the formation of thick layers of molasse deposits. The Caucasus is especially beautiful in these places. Photos of the local gorges and mineral springs are breathtaking. It was these lands that Lermontov sang about while in his famous exile.
The peculiarity of the occurrence and composition of the rocks, together with this, indicate that this territory was previously a sea. This was about 230 million years ago. The continental block was uplifted and covered with shallow water. This structure collapsed after the emergence of the Greater Caucasus. Then troughs arose here, in the place of which colossal receptacles for earthly rocks appeared. This process continues today, which may explain the frequent cataclysms.
Intermountain massif
It is located south of the Greater Caucasus. In the era when the Alps first formed (about 200 million years ago), there was an elevated element of the earth's crust. It was a carbonate platform that looked like a small continent. However, with the beginning of the formation of mountains (30 million years ago), this area began to sag and fall down. The sea, which was at the center of the structure, gradually split into the Black Sea and Caspian Seas.
These are the two interconnected parts. Their tectonic structure is interesting. The Caucasus (a table with important information is presented below) can be divided into three segments. These are the Azerbaijani and Georgian blocks, as well as the Dzirul crystalline massif that separates them.
Study history and resources
Thanks to many internal processes, the structure of the Caucasus allowed various natural resources to appear here. People who lived in those places in ancient times learned to mine and process them. Numerous traces of human activity can still be found in forgotten mines of gold, silver, lead, copper, oil, coal, etc.
Local subsoil stores about 200 billion as well as natural gas. These are large reserves that will last for several decades.
There has always been interest in the structure of this land - people wanted to understand where such resources came from. The first attempts to study the geology of the Caucasus date back to the 18th century, when scientific expeditions initiated by Lomonosov were sent here.
In the 19th century, Musin-Pushkin and Dubois de Montpere went here for research. However, the real father of the study of the geology of the Caucasus is the German specialist Hermann Abikh. He took Russian citizenship and often traveled to the south of the country in the 60s of the 19th century. The subject of his study was tectonic structure. For his numerous discoveries, he became an honorary member of the St. Petersburg Academy of Sciences.
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The Achishkho mountain range is the closest ridge to Red Polyana and the most picturesque. The highest mountain, Achishkho, has a height of 2391 meters above sea level. An interesting fact about the name of the ridge: “Achishkho” translated from Abkhaz means “horse”. This is confirmed by the view from below, from Polyana to the mountain range. If you look closely, you can see the outline of a horse. The most popular hiking route passes through a special place located on the mountainside, approximately 1800 meters above sea level, where there was a weather station from the 30s to the 90s.
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The Aibga mountain range is located on the territory of the Sochi National Park, on the eastern side of Krasnaya Polyana. The ridge extends over 20 kilometers and consists of four highest points called peaks. The most popular peak mountain among tourists is the Black Pyramid, 2375 meters above sea level. It has an unusual shape, which makes it especially popular among climbers. In addition, from the top of the mountain there is a wonderful, breathtaking landscape. Having conquered this mountain, you will see the valley of the Mzymta River, the peaks of Chugush and Pseashkho.
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One of the most beautiful resort places in our country is Dombay. The main attractions of this city are its picturesque places. The Mussa-Achitara ridge is considered the most picturesque ridge in this part of the Caucasus. In order to appreciate all the beauty that surrounds the guests of the resort, you need to climb the mountainside by cable car. From this place there is a wonderful picturesque view of the peaks and glaciers of the Main Range, the Teberda and Gonachkhiri valleys.
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Ine Peak is located near the place where the northern Dzhugurlutchat glacier originates. The name of the mountain is translated as “Needle”; the mountain got its name because of its pointed top; this unusual view for mountains attracts many tourists from all over the world. The top of Ine Peak is covered with snow all year round, and although its sheer cliffs are relatively difficult to conquer, the top of Ine Peak is quite a popular place among climbers. The height of the “needle” reaches 3455 meters, which is about 600 meters lower than the highest mountain of the Caucasus watershed ridge. It is best to view the mountain from the site of Mount Mussa-Achi-Tara; it is 400 meters lower than Ine Peak, but in exchange it can be reached by cable car.
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In the North Caucasus, among the Dombay glade, somewhat east of the Back (Small) Belalakai mountain, there is a peak called Sufrudzhu. The height of the mountain is 3871 m. A wide depression divides the massif into two even parts - Southern and Northern. Both peaks are clearly visible from the Musat-Cheri ski resort. The southern part was called Sufrudju's Tooth, which means "Tiger's Fang". The massif stretches for 3600 m and acts as the main attraction of the mountainous Dombay.
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Belalakai is a mountain located next to the village in Dombay, since the village is a resort. The mountain has become a symbol of this village and attracts a lot of tourists. Its height is 3861 meters. Although the height of this mountain is 200 meters lower than the highest in Abkhazia, it is no less a landmark. Belalakai owes its fame to quartz. Most of the mountain consists of dark soil rocks and dark granite, however, due to centuries-old geological processes, there are deposits of quartz on the mountain. It is this quartz that created the white stripes that decorate the top of this mountain; the white stripes of Belalakai are especially visible in late summer. Due to the beauty of the local landscapes, the mountain has been mentioned more than once in songs and poems.
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Dzhuguturluchat is a relatively small massif in the Greater Caucasus Range. The mountain range rose to a height of 3921 meters, which is only 120 meters less than the highest point on the Caucasus ridge. In the highest areas of the mountain range there are herds of aurochs; it was they who gave these mountains the name “Dzhugurluchat” - which translates as: “herd of aurochs”. The mountain range originates from the Dombay plateau, however, the most beautiful places open from a place called “Mussa-Achi-Tara”; this is where most tourists gather.
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Cheget is one of the highest mountains in the Caucasus. Its height reaches about 3770 meters. It is a popular tourism destination among travelers. From the mountain you can enjoy the view of the highest peak in Europe – Elbrus. Another feature of Mount Cheget is the second line of the cable car, which passes through an area where there is snow that does not melt throughout the year.There are three lines of the cable car in total. The height of the first reaches about 1600 meters. It is one of the most popular for tourists who come to Cheget to enjoy the view of Elbrus.
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This mountain, after Elbrus, is the second most popular among climbers. This is because it is also quite high - 4454 meters above sea level.
There are several ways to get to the mountain: by cable car or on foot. Tourists who choose the first method can use the Cheget cable car at the final point, where small cafes are located. The second and more difficult path, which takes several hours, is from the Cheget meadow along a path already crowded with tourists. However, it is better to hit the road with an experienced guide, otherwise there is a chance of getting lost in the mountains.
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The North Caucasus will captivate many tourists with its beauty and landscapes. Mount Semenov-Bashi, located in the east of the Caucasus Range, is no exception. In reality, it is just a protrusion 3602 m high above the ground. The mountain was named in honor of the Russian explorer P.P. Semenov-Tyan-Shansky. This man was a traveler and was the chairman of the Russian Geographical Society.
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Mount Chotcha is part of the Caucasus range, which is famous for its picturesque mountains and rocks. Chotcha, unlike other mountains, is divided into two parts, as if someone cut the mountain in the middle into two halves. Unlike mountains that have just a smaller mountain next to them, at first glance you can see that the mountain has one base on which there are two rocks. The rock in the foreground is lower than the back one; it is 3637 meters high, which is 400 meters lower than the highest mountain of the Caucasus range. The second rock is only three meters higher than the first, it is 3640 meters above sea level.
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Mount Ertsog is on the list of one of the most visited places in the Caucasus range. The Alibek River flows at the foot of the mountain; in addition to the mountain itself, this place has a very beautiful lowland. In the gorge where the river flows, a massive slope descends; it becomes especially beautiful in the spring, when the sun illuminates the slope full of bright green vegetation. Mount Erzog is part of the Teberdinsky ridge; the ridge itself encircles a lowland with a river and makes a very strong impression on tourists who visit it.
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Mount Sulokhat is located in the Dombay region and is one of the largest points of the Caucasian watershed ridge. The height of the mountain is 3439 meters, which is about 600 meters lower than the largest mountain on the Caucasus ridge. Mount Sulohat is surrounded by many legends, the most popular about the origin of the name of the mountain. In ancient times, the foot of the mountain was inhabited by the Alan tribe. In this tribe there lived a girl named Sulohat, she was of extraordinary beauty and courage and was the daughter of the leader of the tribe.
1. What is the Caucasus. Geography, structure, structure.
Many people are familiar with the Caucasus.
Gigantic mountain ranges crowned with snowy peaks raised above the clouds. Deep gorges and abysses. Endless steppe expanses. Subtropical vegetation of the warm shores of the Black Sea, dry semi-deserts of the Caspian region, flowering alpine meadows of mountain slopes. Stormy mountain streams with waterfalls, the serene surface of mountain lakes, and drying up steppe rivers of the foothills. Failed volcanoes of Pyatigorye and volcanic lava highlands of Armenia. These are just some of the contrasts of this huge region.
What is the Caucasus geographically?
In a direction approximately from north to south, the Caucasus consists of the following parts.
The Cis-Caucasian Plain, which is a natural continuation of the Russian or East European Plain, begins south of the Kuma-Manych depression. The western part of the Ciscaucasia is crossed by the flat part of the Kuban River, which flows into the Sea of Azov. The eastern part of the Ciscaucasia is irrigated by the flat section of the Terek River, which flows into the Caspian Sea. In the central part of the Ciscaucasia lies the Stavropol Upland with average heights from 340 to 600 meters and individual elevations up to 832 m (Mount Strizhament).
The next part is the Greater Caucasus. It extends over a distance of about 1,500 kilometers, from the Taman to the Absheron peninsulas.
The Greater Caucasus is formed by four mostly parallel ridges, rising step by step from north to south. The smallest Pasture Range, it is also called the Black Mountains. Behind it rises the Rocky Ridge. These two ridges are cuesta ridges, with a gentle northern slope and a steep southern slope. After Skalisty rises the Side, or Front Range, where Elbrus, Dykh-Tau, Koshtan-Tau, Kazbek and others are located.
The narrow Arkhyz-Zagedan, Bezhetinskaya and other depressions separate the Side Range from the Main, or Watershed Range.
The narrow southern slope of the Greater Caucasus gives way to the Transcaucasian depression, which consists of the Rioni or Colchis depression and the Kura depression. Between the depressions there is a narrow Suramsky or Likhsky ridge.
Even further south lies the Transcaucasian Plateau, which is part of the vast Western Asian Plateaus. In the north and northeast of the highlands are the Lesser Caucasus ranges. And to the southwest of the Lesser Caucasus stretch the lava massifs of the Armenian-Javakheti Highlands.
But the Caucasus has not always been like this, and will not always be like this. This, in general, quite obvious consideration serves as a convenient transition to the question of how exactly the Caucasus was formed. Behind the rather dry phrase “geological history of the Caucasus” there are stages in the life of the living planet, the Earth, full of drama and impressive disasters. Millions of years of consistent and sometimes leisurely changes end in impulses of huge volcanic eruptions and, conversely, outbreaks of catastrophic events respond over a subsequent time interval of millions of years. And the calm muddy bottom of the warm sea becomes an icy mountain peak, from the edge of which rock falls collapse with a roar.
It is very difficult to identify a point in time from which to begin describing the history of the Caucasus. Simply because to fully understand the processes at a certain point in time, one must also know the previous episodes. When you talk about the collapse of strata, the formation of mountains at a certain point in time, the question always arises of how and when these strata themselves were formed. And those may be the products of the destruction of some more ancient mountains or structures. And so behind each ancient geological episode one can see a clear or not so clear picture of previous events...
2. Evolution of the Caucasus. From seas to mountains.
The starting, albeit very conditional, period in time, from which we can say that events are already related to the processes that led to the formation of the modern Caucasus, is the second half and end of the Paleozoic era (that is, the period of time from 400 to 250 million years ago). l.n.). At that time there were not only people on Earth, but also dinosaurs. Let's take a mental look at the entire region at that time.
There has been a strong and relatively calm Russian platform for a long time. It came together about 2 billion years ago from three blocks of crystalline foundation. These blocks were formed even earlier - from the merger of basalt plates and the further melting of their heap into granites of the continental crust.
In the second half of the Paleozoic, the Russian Platform became part of the Laurasia continent. It is gradually moving closer to another continent, Gondwana.
Let us recall the main provisions of the concept of moving lithospheric plates. Blocks of relatively hard rocks - lithospheric plates - move along the surface of the mantle under the influence of mantle convective flows - very slow on the time scale familiar to us, but quite noticeable on the geological time scale. Plates are either oceanic or continental. The continental plate along its periphery includes areas with oceanic crust. Lithospheric plates float on the surface of the asthenosphere (the asthenosphere is the upper weakened layer of the mantle with reduced viscosity) and move along it. This movement is caused by the convective movement of the mantle as a whole. The earth's crust is of two types - continental (granite) and oceanic (basalt).
New oceanic crust is formed in spreading zones - mid-ocean ridges, where the asthenosphere material builds up the plate, and is absorbed in subduction zones, where the plate material returns to the asthenosphere.
So, in the second half of the Paleozoic there is a convergence of Laurasia (North America plus Europe) and Gondwana (Africa plus South America).
In the process of convergence in the south of the Russian Platform, where the Ciscaucasia lies today, an area of folding is formed, a mobile belt associated with the existence of a subduction zone, when the oceanic crust is absorbed under the continent, weakening its edge and providing volcanic activity and mobility of the crust of the entire region.
The global convergence at that time, at the end of the Paleozoic, ended with the collision of Laurasia and Gondwana and the formation of the supercontinent or supercontinent Pangea. Between the continents connected in the area of the modern Mediterranean Sea and diverging to the east, a wedge-shaped space was formed - the Tethys Ocean.
Locally, in the process of convergence, the mentioned moving belt experienced its evolution and lived its history. Its history is a local episode of the global picture of the convergence of lithospheric plates.
Compressional deformations in the mobile belt, which created the folded structure, began in the middle of the Visean century of the early Carboniferous period, the Carboniferous (about 335 million years ago). The cause of the deformations was the pressure of the oceanic crust on the belt in the process of convergence of continental blocks. They turned the mobile belt, the future Scythian platform, into an orogen, a mountain structure.
In the Permian period (its time interval from 299 to 250 million years ago), the orogen began to experience collapse, the rapid disappearance of mountains. The reasons for the collapse are the following. Since this orogen was not sandwiched between continental masses, but arose as a result of the movement of the oceanic plate under the continent, then with the weakening of the pressure and subsidence of the oceanic plate, the forces uplifting the mountains also weakened. The blocks that made up the mountains began to slide down. Then the crumpled, compressed, compressed folds were penetrated by granite intrusions (intrusions). These intrusions seemed to reinforce and fix the folds. Pressure and temperature turned sedimentary and volcanic rocks into chlorite and sericite schists, which mainly comprise the Scythian plate.
Thus, along the northern edge of the Tethys Ocean, on the site of today’s plains of Ciscaucasia, a young (compared to the ancient East European or Russian platform) Scythian platform was formed from a mobile belt. Its latitudinal folds and slightly still moving heterogeneous blocks preserve memories of compression processes and the life of a mountain structure. Despite the fact that we practically cannot see them.
So, the main result of the events of that time, the end of the Paleozoic, was the formation of the Scythian platform, attached to the Russian platform along its current southern edge.
As geologists know, supercontinents are unstable formations. Immediately after formation, the supercontinent tends to break up. The reason for this is the same mantle flows that clustered the continents and pushed them together. Following the formation of a supercontinent, the lithosphere, which goes under it from all sides in subduction zones, accumulates under it and then floats up, splitting the supercontinent.
The Triassic period (250 - 200 million years ago, this is the first period of the Mesozoic era) was precisely the time when the split of Pangea began. The blocks of lithospheric plates that made up Pangea began to move away from each other. Africa and Eurasia began to move away from each other. The fragmentation of the continental bridge between Europe, Africa and America began.
When continental blocks move apart from each other, the oceanic crust located between these blocks grows (in fact, this is what spreading consists of). Augmentation occurs when new crust forms at mid-ocean ridges.
In our case, the axis of expansion of the Tethys Ocean fell on the northern edge of Gondwana. It was due to this, due to the formation of rifts, that continental blocks broke away from Gondwana, beginning their journey towards Eurasia. Let us recall that a rift is the initial stage of the development of the ocean as a structure; a rift may later become (but will not necessarily become!) a mid-ocean ridge. A rift is a gap that forms when the crust is pushed sideways by rising magma. Thus, in the Late Triassic, Iran and, apparently, central Türkiye broke away from Arabia. At the end of the Triassic - the beginning of the Jurassic (the Jurassic period lasts from 199 to 145 million years ago), heterogeneous blocks broke away from Gondwana, which subsequently formed into the Transcaucasian massif (in our time it separates the Greater and Lesser Caucasus).
On the opposite side of the Tethys Ocean, on the southern edge of Eurasia, oceanic crust was absorbed in subduction zones along the edge of the plate. Apparently, the formation of the crust exceeded the rate of movement of the lithospheric plates of Eurasia and Africa.
Subduction of oceanic crust caused the emergence of a volcanic belt along the northern coast of the Tethys Ocean. Apparently, in the Triassic it was an Andean-type belt, like the modern western coast of South America.
During the Jurassic period, the second period of the Mesozoic era, the collapse of the supercontinent Pangea and its parts continued. And at the time described, the turn of the collapse of Gondwana came. In the Early Middle Jurassic, Gondwana began to split into South America, Africa with Arabia, Antarctica and India. The split of South America and Africa (with Arabia) naturally led to the growth of oceanic lithosphere between them and, which is very important for the region we are describing, to a reduction in the distance between Africa and Eurasia. The Tethys Ocean began to shrink in size.
Where the oceanic crust of the Tethys Ocean was intensely moving under the edge of the Scythian plate, a weakening of this edge occurred. This is a consequence of the fact that the oceanic plate, going down, melts, and the excess of the molten substance tries to break through upward.
Rifting began to occur on the weakened edge of the plate - the formation of rifts with the moving apart of the broken fragments of the previous foundation. The new crust expanded towards the ocean. The crust was generally continental, granitic, but intruded by basaltic outpourings. Thus (at the end of the Lower and beginning of the Middle Jurassic, about 175 million years ago) the so-called Greater Caucasus basin was formed. It was a regional sea. It was separated from the main Tethys ocean by an island volcanic arc, the existence of which is also explained by the weakening of the lithosphere in the subduction zone, underthrust, and the breakthrough of magma to the surface with the formation of volcanoes. The Greater Caucasus basin was 1700-1800 km long and 300 km wide.
Late Jurassic, 145 million years ago. The Greater Caucasus basin and island arc already exist. Note that the pictures depict structures, not seas and land. Although often the structures and pools coincide.
Almost immediately after its formation, the crust of the Greater Caucasus Basin began to sink under the continent, under the margin of Eurasia. The movement of the crust of the Tethys Ocean being absorbed to the south, causing weakening and stretching of the margin, simultaneously tries to close the newly formed basins.
And the system of volcanic arcs was awaiting a new transformation. This time at the beginning of the next, Cretaceous, period (it occupies the range of 145-65 million years ago). Stretching of the cortex in the rear of the arcs occurred again, for the same reasons as before. And already the stretching and spreading was so significant that as a result, a deep-sea depression of the Southern Caspian with oceanic crust was formed. To the west, the crust simply thinned, forming the base of the vast Proto-Black Sea basin.
At the beginning of the Late Cretaceous, about 90 million years ago, the first collision of Gondwanan continental blocks with the Lesser Caucasus island arc occurred. These blocks are central Turkey, or Kirsehir (split off from Gondwana, as mentioned earlier, in the Triassic) and the Daralagez, or South Armenian block (split off from Afro-Arabia at the end of the Early Cretaceous, 110 million years ago). The northern branch of the Tethys Ocean closed and disappeared. The remains of the bottom of this ocean, rocks called ophiolites, now lie in a strip along Lake Sevan and in a number of other places. Immediately after the collision, the subduction zone jumped further south, to the edge of the newly pushed continental blocks. This clicking relieved the compressive stress in the zone of volcanic arcs and tension again occurred in the rear of the arc. At the end of the Late Cretaceous, approximately 80 million years ago, as a result of this back-arc spreading, the Western Black Sea and Eastern Black Sea deep-sea ocean basins were formed. They are the basis of the structure of the modern Black Sea, and it can be considered that the Black Sea was created precisely then. By now, these depressions are completely filled with sediments.
Sometimes, when talking about the origin of the Black and Caspian Seas, they are called the remnants of the Tethys Ocean. This is not entirely true; these seas, as we see, are the remains of back-arc basins that were separated from the ocean by island arcs.
By the way, in the same Late Cretaceous, on the other coast of the Tethys Ocean, the southern one, an interesting phenomenon occurred. Due to the compression of the oceanic crust (as we remember, the lithospheric plates of Africa and Eurasia continued to move closer together) and the reduction of the space between the blocks of plates, this oceanic crust literally crawled onto the edge of the Arabian coast from above, and did not sink under the continent, as happens in most cases. This phenomenon is called obduction. The oceanic crust continues to lie there, occupying large areas. These are the ophiolites of Oman and others known to scientists.
Thus, the main trend in the Mesozoic period of time, in relation to the region under consideration, was the formation and evolution of island volcanic arcs and back-arc basins. This evolution is associated with the subduction zone.
Time continued to flow. The Mesozoic era gave way to the Cenozoic.
The region, like the entire planet, has entered a new period of development. Both the planet and individual places were characterized by new specific events. For the planet as a whole, the boundary of the Cretaceous (this is still the Mesozoic) and the Paleogene (this is the Cenozoic) is marked by the gradual extinction of dinosaurs and the arrival of mammals to replace them. In the plant world, flowering plants enter the scene with full power, crowding out gymnosperms.
At the beginning of the Paleogene period (the Paleogene occupies the range 65 - 23 million years ago and is divided into the Paleocene, Eocene and Oligocene), the situation in the region we are talking about continued to be, in principle, similar to the Mesozoic. The Tethys Ocean gradually shrank, Africa moved closer to Eurasia. Oceanic crust subducted under the margin of Eurasia framed by island arcs.
Scientists managed to reconstruct the appearance of the region of the future Caucasus at that time. Of course, it was different from today. But its modern elements and parts became more and more clearly visible in the structures, and sometimes they looked completely different from what we see today.
Above modern Ciscaucasia, above the Scythian plate (and extending much further north) lay a vast sea basin. It was the shelf of the Eurasian continent with not too great depths. Carbonate (limestones and marls) and clay sediments accumulated at its bottom, covering the structures of the Scythian plate.
In the future, this part will become the lowland Ciscaucasia and the northern slope of the Greater Caucasus.
To the south lay a volcanic arc that separated the Greater Caucasus Basin from the rest of the Tethys Ocean. Its northern strip will in the future be the underwater rises of the Shatsky shaft and the Kurdamir shaft, as well as the Dzirul ledge. The basis of this strip is the Transcaucasian massif. The southern part of the arc will in the future become the Lesser Caucasus.
Even further south lay the vast but shrinking Tethys Ocean, and beyond it jutted out the Arabian Plate, still integral with Africa. This entire mass of blocks gradually approached the island arc.
35 million years ago, towards the end of the Eocene epoch (the second Paleogene epoch after the Paleocene), the Arabian salient almost came close and came into contact with the island arc. The bed of the Tethys Ocean, its bottom, was swallowed up under the arc.
Starting from the Oligocene (occupies the interval 34-23 million years ago), the collision of the Arabian protrusion with the island arc began. The consequence of this was the pushing of fragments of the island arc to the north and the gradual reduction of the back-arc basin. The reduction in distance was especially large directly opposite the Arabian salient, where movements reached 300-400 kilometers. The island volcanic arc curved to the north.
Oligocene, 34-23 million years ago. The beginning of block collision and crowding. The beginning of the rise of the Caucasus.
In the Oligocene, the Greater Caucasus was not yet a mountain structure. Both the Greater and Lesser Caucasus were islands and underwater hills. Their number and the area they occupied increased.
Finally, the entire space of the former Greater Caucasus basin, capable of shrinking, has ended. There was no bark left to be absorbed. Squeezed between the continental blocks between the edge of Eurasia and Afro-Arabia, the Caucasus zone has become the scene of a new stage of development (or another catastrophe, as often happens). Monstrous forces and energies again transformed the collision zone. From the late Miocene (the Miocene is a period of time from 23 to 5.4 million years ago), the uplift increased sharply. The Greater Caucasus began to rise. The sediments layered over many millions of years, lining and forming the seabed, began to turn into mountains. Apparently, at the end of the late Sarmatian century, 12 million years ago. Mountainous terrain formed in the Caucasus. It is assumed that the relief then was a combination of low plains in internal depressions, denudation and abrasive-erosive plains and ridges and remnant massifs up to 700 meters high above them, rising several hundred meters above them.
Fig.7 End of the Miocene, 12 million years ago. Formation of the Caucasus Mountains.
The continuing pressure of Afro-Arabia led to a weakening of the earth's crust in the area in the direction of the "edge" up to present-day Pyatigorsk, and 7-9 million years ago magmatic diapirs of the mineral water group formed there (diapiric structures are folds curved upward due to the pressure of magma from below ). Molten magma tried to make its way to the surface, swelling the sediments of the seas. But its viscosity was too high, the magma did not penetrate into the open sky, and failed volcanoes - laccoliths - now adorn the Ciscaucasia.
In the late Miocene, 7-6 million years ago. The volcanism of the Lesser Caucasus sharply increased. Extensive volcanic covers were formed from lavas and products of explosive eruptions.
In the late Pliocene, by the time of 2 million years ago. The Elbrus volcano and the Verkhnechegemskaya caldera were formed, and volcanoes arose in the Kazbek region.
Finally, in the Quaternary period (began 1.8 million years ago), the relief of the Caucasus sharply rejuvenated due to ongoing uplifts under conditions of compression between lithospheric plates. In the Greater Caucasus, the uplift of the outer elements of the mountain structure, the former shelf with a crystalline base, and the tucking of the southern slope continued. In the Lesser Caucasus, blocks simply rose along fault lines.
In the Quaternary period, volcanism in the Lesser Caucasus existed only in certain parts of it. But nearby, in the Armenian-Javakheti Plateau, the eruptions were very intense, forming the volcanoes Aragats and Ararat.
The main result of the Cenozoic events, therefore, was the collision of lithospheric plates, the closure of the Tethys Ocean and the uplift of mountain structures in place of sea basins.
3. Traces of events. What do we see today?
Now, knowing and understanding the history of the formation of the Caucasus, let us again pass from north to south over it and get acquainted with the traces of past processes. This will be a very superficial acquaintance.
The plains of Ciscaucasia are composed of Neogene and Quaternary deposits on the surface. Below them, and further down under the Mesozoic and Paleogene strata, lies the uneven surface of the Scythian plate.
Thanks to pressure from Arabia, the structures of the Scythian plate are partly raised, forming the Stavropol and Mineralovodsk arches.
To the right and left of this zone are the forward deflections of the plate foundation - Terek-Caspian and Western and Eastern Kuban. Thanks to their subsidence, for example, the floodplains of the Kuban and the salt lakes of the Kuma delta were formed (due to the filling of river beds with sediments).
Even further south, the Northern slope of the Greater Caucasus begins.
The rocky ridge is composed (ridge and summit plateau) of Middle Jurassic and Lower Cretaceous limestones.
In the Labino-Malkin zone, in the central part of the northern slope, the foundation of the plate simply reaches the surface in the river valleys, bent back by the monstrous pressure of the converging continents. The southern end of the Labino-Malkin zone is the Front Range, its central part.
The rising Vodorazdelny and Bokovoy ridges in the Central Caucasus are composed of already hard crystalline rocks. The depression between them is composed of Early Jurassic shales.
In the Western Caucasus, the Vodorazdelny Range is composed of crystalline rocks. The lateral one is sedimentary Paleozoic.
In the Eastern Caucasus, the ridges are composed mainly of Jurassic shales
The southern slope of the Greater Caucasus is composed of Lower-Middle Jurassic shale strata. These are the same deep-sea sediments of the Greater Caucasus Basin that were mentioned earlier.
To the south is the Transcaucasian massif. In its highest place, in the center, in the Dzirula ledge, ancient pre-Paleozoic rocks are close to the surface. This is the foundation of the northern part of the former volcanic arc.
Well, then there are the Lesser Caucasus mountains, composed of volcanic-sedimentary strata of the Cretaceous and Paleogene. The thicknesses were crumpled into folds, then broken into blocks and pushed upward. This is a former volcanic arc, its southern part. The territory of the west and south of the Lesser Caucasus (Armenia, Adjara, Trialeti) is composed of Paleogene and Cretaceous marine sediments with products of underwater and above-water volcanic eruptions. The north and east of the Lesser Caucasus are composed of Jurassic marine rocks also with eruption products.
In conclusion, it is interesting to look at the region from above. It is clearly visible how the Arabian Plate is pressed into a jumble of microblocks, putting pressure on the Lesser Caucasus and further through Transcaucasia to the North Caucasus. How the chain of the Pontic Mountains (northern coast of Turkey) - Lesser Caucasus - Elburz (ridge along the southern coast of the Caspian Sea) stretches, marking the line of closure of the northern branch of the Tethys Ocean. Just to the south, the Taurus Mountains (southern Turkey) – Zagros (ridge in southwest Iran) range marks the southern branch of the Tethys Ocean. And between them, these chains, are Central Türkiye and Iran, pushed to the sides by the protrusion of the Arabian Plate.
Global view of the region.
This is what the geological history of the Caucasus looks like. As in other places on the planet, every stone means something, every slope testifies to processes millions and billions of years ago. Both small stones and structures the size of half a continent can tell their own stories, intertwining and complementing each other. So that the end result is a holistic history of the region in all its impressive dynamics. It is not easy to describe the life of the lithosphere. She doesn't know human emotions. And the witnesses to the events are not people either. And the time scales do not fit into the usual size range. Only by gathering together in the knowledge of scientists, events receive literary life. But the stones don't need us. It seems that we need them and are drawn to explore and describe them.
Steppe Ranger
Used literature:
History of the Tethys Ocean. ed. A.S. Monin, L.P. Zonenshain. 1987 156 p.
Paleogeography. A.A. Svitoch, O.G. Sorokhtin, S.A. Ushakov. 2004 448 p.
Geology of Russia and adjacent territories. N.V. Koronovsky. 2011 240 p.
Physical geography of the USSR. F.N. Milkov, N.A. Gvozdetsky. 1975 448 p.
Poetry of the Caucasus Mountains. M.G. Leonov. Nature. 2003 No. 6.
Here is a detailed map of the Caucasus Mountains with the names of cities and towns in Russian. Move the map while holding it with the left mouse button. You can move around the map by clicking on one of the four arrows in the upper left corner.
You can change the scale using the scale on the right side of the map or turning the mouse wheel.
In which country are the Caucasus Mountains located?
The Caucasus Mountains are located in Russia. This is a wonderful, beautiful place, with its own history and traditions. Coordinates of the Caucasus Mountains: northern latitude and eastern longitude (show on large map).
Virtual walk
The “man” figurine above the scale will help you take a virtual walk through the cities of the Caucasus Mountains. By clicking and holding the left mouse button, drag it to any place on the map and you will go for a walk, while inscriptions with the approximate address of the area will appear in the upper left corner. Select the direction of movement by clicking on the arrows in the center of the screen. The “Satellite” option at the top left allows you to see a relief image of the surface. In the “Map” mode you will have the opportunity to get acquainted in detail with the roads of the Caucasus Mountains and the main attractions.
antiqus classics
Caspian mountains
- Caspian mountains
- and gates (Greek Κασπία ὄρη, Latin Caspii monies).
- 1. The fanatical mountains between Armenia and Albania on the one hand and Media on the other (now Qaradagh, Siah-Koh, i.e. Black and Talysh Mountains). In a broad sense, this name refers to the entire chain of mountains running south of the river. Arak (from the Kotur River to the Caspian Sea). Here were the so-called.
Caspian Gate (Kaspiapili), a narrow mountain pass 8 Roman miles long and one chariot wide (now the Chamar pass between Narsa-Koh and Siah-Koh). This was the only way from Northwestern Asia to the northeastern part of the Persian state, because the Persians locked this passage with iron gates, which were guarded by guards (claustra Caspiarum).
The Caucasus Mountains are a mountain system between the Black and Caspian seas.
It is divided into two mountain systems: the Greater Caucasus and the Lesser Caucasus.
The Caucasus is often divided into the Northern Caucasus and Transcaucasia, the border between which is drawn along the Main, or Watershed, ridge of the Greater Caucasus, which occupies a central position in the mountain system.
The most famous peaks are Mt. Elbrus (5642 m) and Mt.
Kazbek (5033 m) is covered with eternal snow and glaciers.
From the northern foot of the Greater Caucasus to the Kuma-Manych depression, the Ciscaucasia stretches with vast plains and hills. To the south of the Greater Caucasus are the Colchis and Kura-Araks lowlands, the Inner Kartli Plain and the Alazan-Avtoran Valley [Kura Depression, within which the Alazan-Avtoran Valley and the Kura-Araks Lowland are located]. In the southeastern part of the Caucasus are the Talysh Mountains (up to 2492 m high) with the adjacent Lenkoran Lowland. In the middle and west of the southern part of the Caucasus is the Transcaucasian Highlands, consisting of the ridges of the Lesser Caucasus and the Armenian Highlands (Aragats, 4090 m).
The Lesser Caucasus is connected to the Greater Caucasus by the Likhsky ridge, in the west it is separated from it by the Colchis Lowland, in the east by the Kura Depression. Length - about 600 km, height - up to 3724 m.
Mountains near Sochi - Aishkho (2391 m), Aibga (2509 m), Chigush (3238 m), Pseashkho and others.
Location of the Caucasus Mountains mountain system on the world map
(the boundaries of the mountain system are approximate)
Hotels in Adler from 600 rubles per day!
Caucasus Mountains or Caucasus- a mountain system between the Black and Caspian seas with an area of ~ 477488 m².
The Caucasus is divided into two mountain systems: the Greater Caucasus and the Lesser Caucasus, very often the mountain system is divided into the Ciscaucasia (North Caucasus), the Greater Caucasus and the Transcaucasus (South Caucasus). The state border of the Russian Federation with the countries of Transcaucasia runs along the crest of the Main Ridge.
Highest Peaks
The largest mountain peaks of the Caucasus Mountains (indicators from different sources may vary).
|
Height, m |
Notes |
|
| Elbrus | 5642 m | the highest point of the Caucasus, Russia and Europe |
| Shkhara | 5201 m | Bezengi, the highest point of Georgia |
| Koshtantau | 5152 m | Bezengi |
| Pushkin Peak | 5100 m | Bezengi |
| Dzhangitau | 5085 m | Bezengi |
| Shkhara | 5201 m | Bezengi, the highest point of Georgia |
| Kazbek | 5034 m | Georgia, Russia (highest point of North Ossetia) |
| Mizhirgi Western | 5025 m | Bezengi |
| Tetnuld | 4974 m | Svaneti |
| Katyn-tau or Adish | 4970 m | Bezengi |
| Shota Rustaveli Peak | 4960 m | Bezengi |
| Gestola | 4860 m | Bezengi |
| Jimara | 4780 m | Georgia, North Ossetia (Russia) |
| Ushba | 4690 m | |
| Tebulosmta | 4493 m | highest point of Chechnya |
| Bazarduzu | 4485 m | highest point of Dagestan and Azerbaijan |
| Shan | 4451 m | highest point of Ingushetia |
| Adai-Khokh | 4408 m | Ossetia |
| Diklosmta | 4285 m | Chechnya |
| Shahdag | 4243 m | Azerbaijan |
| Tufandag | 4191 m | Azerbaijan |
| Shalbuzdag | 4142 m | Dagestan |
| Aragats | 4094 m | highest point of Armenia |
| Dombay-Ulgen | 4046 m | Dombay |
| Zilga-Khokh | 3853 m | Georgia, South Ossetia |
| TASS | 3525 m | Russia, Chechen Republic |
| Tsitelikhati | 3026.1 m | South Ossetia |
Climate
The climate of the Caucasus is warm and mild, with the exception of the highlands: at an altitude of 3800 m there is the border of “eternal ice”. In the mountains and foothills there is a large amount of precipitation.
Flora and fauna
The vegetation of the Caucasus is distinguished by its rich species composition and diversity: oriental beech, Caucasian hornbeam, Caucasian linden, noble chestnut, boxwood, cherry laurel, Pontine rhododendron, some types of oak and maple, wild persimmon, as well as subtropical tea bushes and citrus fruits grow here.
In the Caucasus there are brown Caucasian bears, lynxes, wildcats, foxes, badgers, martens, deer, roe deer, wild boars, bison, chamois, mountain goats (turs), small rodents (forest dormouse, vole). Birds: magpies, blackbirds, cuckoos, jays, wagtails, woodpeckers, owls, eagle owls, starlings, crows, goldfinches, kingfishers, tits, Caucasian grouse and mountain turkeys, golden eagles and lambs.
Population
More than 50 peoples live in the Caucasus (for example: Avars, Circassians, Chechens, Georgians, Lezgins, Karachais, etc.) which are designated as Caucasian peoples. They speak Caucasian, Indo-European, and Altai languages. Largest cities: Sochi, Tbilisi, Yerevan, Vladikavkaz, Grozny, etc.
Tourism and recreation
The Caucasus is visited for recreational purposes: there are many seaside resorts on the shores of the Black Sea, and the North Caucasus is popular for its balneological resorts.
Rivers of the Caucasus
Rivers originating in the Caucasus belong to the basins of the Black, Caspian and Azov seas.
- Bzyb
- Kodori
- Ingur (Inguri)
- Rioni
- Kuban
- Podkumok
- Araks
- Liakhva (Big Liakhvi)
- Samur
- Sulak
- Avar Koisu
- Andean Khoisu
- Terek
- Sunzha
- Argun
- Malka (Kura)
- Baksan
- Chegem
- Cherek
Countries and Regions
The following countries and regions are located in the Caucasus.
- Azerbaijan
- Armenia
- Georgia
- Russia: Adygea, Dagestan, Ingushetia, Kabardino-Balkaria, Karachay-Cherkessia, Krasnodar Territory, North Ossetia-Alania, Stavropol Territory, Chechnya
In addition to these countries and regions, there are partially recognized republics in the Caucasus: Abkhazia, South Ossetia, Nagorno-Karabakh.
Largest cities of the Caucasus
- Vladikavkaz
- Gelendzhik
- Hot Key
- Grozny
- Derbent
- Yerevan
- Essentuki
- Zheleznovodsk
- Zugdidi
- Kislovodsk
- Kutaisi
- Krasnodar
- Maykop
- Makhachkala
- Mineralnye Vody
- Nazran
- Nalchik
- Novorossiysk
- Pyatigorsk
- Stavropol
- Stepanakert
- Sukhum
- Tbilisi
- Tuapse
- Tskhinvali
- Cherkessk
Cheap flights to Sochi from 3000 rubles.
Where is it located and how to get there
Address: Azerbaijan, Armenia, Georgia, Russia
Geographical location. On the huge isthmus between the Black and Caspian seas, from the Taman to the Absheron peninsula, there are the majestic mountains of the Greater Caucasus.
North Caucasus- This is the southernmost part of Russian territory. The border of the Russian Federation with the countries of Transcaucasia runs along the ridges of the Main, or Watershed, Caucasian Range.
The Caucasus is separated from the Russian Plain by the Kuma-Manych depression, on the site of which a sea strait existed in the Middle Quaternary.
The North Caucasus is an area located on the border of the temperate and subtropical zones.
The epithet “the best” is often applied to the nature of this territory. Latitudinal zonality is replaced here by vertical zonality. For a resident of the plains, the Caucasus Mountains are a vivid example of the “multi-storey™” of nature.
Remember where the southernmost point of Russia is located and what it is called.
Features of the nature of the North Caucasus. The Caucasus is a young mountain structure formed during the period of Alpine folding. The Caucasus includes: Ciscaucasia, Greater Caucasus and Transcaucasia. Only the Ciscaucasia and the northern slopes of the Greater Caucasus belong to Russia.
Rice. 92. Orographic scheme of the Caucasus
The Greater Caucasus is often presented as a single ridge. In fact, it is a system of mountain ranges. From the Black Sea coast to Mount Elbrus is the Western Caucasus, from Elbrus to Kazbek is the Central Caucasus, east of Kazbek to the Caspian Sea is the Eastern Caucasus. In the longitudinal direction, an axial zone is distinguished, occupied by the Vodorazdelny (Main) and Bokovy ridges.
The northern slopes of the Greater Caucasus form the Skalisty and Pastbishchny ridges. They have a cuesta structure - these are ridges in which one slope is gentle and the other is steep. The reason for the formation of a quest is the interlayering of layers composed of rocks of different hardness.
The chains of the Western Caucasus begin near the Taman Peninsula. At first, these are not even mountains, but hills with soft outlines. They increase when moving to the east. Mountains Fisht (2867 m) and Oshten (2808 m) - the highest parts of the Western Caucasus - are covered with snowfields and glaciers.
The highest and grandest part of the entire mountain system is the Central Caucasus. Here even the passes reach an altitude of 3000 m; only one pass - the Cross Pass on the Georgian Military Road - lies at an altitude of 2379 m.
The highest peaks in the Central Caucasus are the double-headed Elbrus, an extinct volcano, the highest peak in Russia (5642 m), and Kazbek (5033 m).
The eastern part of the Greater Caucasus is mainly the numerous ridges of mountainous Dagestan (translated as the Country of Mountains).
Rice. 93. Mount Elbrus
Various tectonic structures took part in the structure of the North Caucasus. In the south there are folded block mountains and foothills of the Greater Caucasus. It is part of the alpine geosynclinal zone.
Oscillations of the earth's crust were accompanied by bending of the earth's layers, their stretching, faults, and ruptures. Through the cracks that formed, magma poured out to the surface from great depths, which led to the formation of numerous ore deposits.
Uplifts in recent geological periods - Neogene and Quaternary - turned the Greater Caucasus into a high-mountainous country. The rise in the axial part of the Greater Caucasus was accompanied by an intense subsidence of the earth's layers along the edges of the emerging mountain range. This led to the formation of foothill troughs: in the west of the Indolo-Kuban and in the east of the Terek-Caspian.
The complex history of the geological development of the region is the reason for the richness of the subsoil of the Caucasus in various minerals. The main wealth of the Ciscaucasia is oil and gas deposits. In the central part of the Greater Caucasus, polymetallic ores, tungsten, copper, mercury, and molybdenum are mined.
In the mountains and foothills of the North Caucasus, many mineral springs were discovered, near which resorts were created that have long gained worldwide fame - Kislovodsk, Mineralnye Vody, Pyatigorsk, Essentuki, Zheleznovodsk, Matsesta. The sources are varied in chemical composition, temperature and are extremely useful.
Rice. 94. Geological structure of the North Caucasus
The geographical location of the North Caucasus in the south of the temperate zone determines its mild, warm climate, transitional from temperate to subtropical. The parallel of 45° N runs here. sh., that is, this territory is equidistant from both the equator and the pole. This situation determines the amount of solar heat received: in summer 17-18 kcal per square centimeter, which is 1.5 times more than the average European part of Russia receives. With the exception of the highlands, the climate in the North Caucasus is mild and warm; on the plains, the average July temperature everywhere exceeds 20°C, and summer lasts from 4.5 to 5.5 months. Average January temperatures range from -10 to +6°C, and winter lasts only two to three months. In the North Caucasus is the city of Sochi, which has the warmest winter in Russia with a January temperature of +6.1°C.
Using the map, determine whether in the foothills of the North Caucasus there are any obstacles to the path of arctic or tropical air masses. What atmospheric fronts pass near this area? Analyze on maps how precipitation is distributed in the North Caucasus, explain the reasons for this distribution.
The abundance of heat and light allows the vegetation of the North Caucasus to develop in the north of the region for seven months, in the Ciscaucasia - eight, and on the Black Sea coast, south of Gelendzhik - up to 11 months. This means that with the appropriate selection of crops, you can get two harvests a year.
The North Caucasus is distinguished by a very complex circulation of various air masses. Various air masses can penetrate this area.
The main source of moisture for the North Caucasus is the Atlantic Ocean. Therefore, the western regions of the North Caucasus are characterized by high rainfall. The annual precipitation in the foothill areas in the west is 380-520 mm, and in the east, in the Caspian region, it is 220-250 mm. Therefore, in the east of the region there are often droughts and hot winds. At the same time, they are often accompanied by dusty, or black, storms. Storms occur in the spring, when the top layers of parched soil, still loosely held together by newly emerged plants, are blown away by strong winds. Dust rises in clouds into the air, obscuring the sky and the sun.
Measures to combat black storms include properly planned forest shelterbelts and advanced agricultural technology. However, until now, due to black storms, several tens of thousands of hectares have to be reseeded (re-seeded), from which the most fertile layer of soil is blown away during dust storms.
Highland climate very different from the plains and foothills. The first main difference is that much more precipitation falls in the mountains: at an altitude of 2000 m - 2500-2600 mm per year. This is due to the fact that mountains trap air masses and force them to rise. At the same time, the air cools and gives up its moisture.
The second difference in the climate of the highlands is the decrease in the duration of the warm season due to the decrease in air temperature with height. Already at an altitude of 2700 m on the northern slopes and at an altitude of 3800 m in the Central Caucasus there is a snow line, or the border of “eternal ice”. At altitudes above 4000 m, even in July, positive temperatures are very rare.
Remember by what amount the air temperature decreases when rising for every 100 m. Calculate how much the air cools when rising to a height of 4000 m, if its temperature at the surface of the earth is +20 ° C. What happens to the moisture in the air?
In the mountains of the Western Caucasus, due to the abundance of precipitation during the winter, a four to five meter layer of snow accumulates, and in the mountain valleys, where it is blown away by the wind, up to 10-12 m. The abundance of snow in winter leads to the formation of snow avalanches. Sometimes one awkward movement, even a sharp sound, is enough for a thousand-ton mass of snow to fly down a steep ledge, destroying everything in its path.
Explain why there are practically no avalanches in the mountains of the Eastern Caucasus.
Think about what differences will be observed in the change in altitudinal zones on the western and eastern slopes.
The third difference in the high-mountain climate is its amazing diversity from place to place due to the height of the mountains, slope exposure, proximity or distance from the sea.
The fourth difference is the uniqueness of atmospheric circulation. Cooled air from the highlands rushes down through relatively narrow intermountain valleys. When descending for every 100 m, the air warms up by about 1°C. Descending from an altitude of 2500 m, it heats up by 25°C and becomes warm, even hot. This is how a local wind is formed - the foehn. Hairdryers are especially frequent in the spring, when the intensity of the general circulation of air masses sharply increases. Unlike a foehn, when masses of dense cold air invade, bora is formed (from the Greek boreas - north, north wind), a strong cold downward wind. Flowing through low ridges into an area with warmer rarefied air, it heats up relatively little and “falls” at a high speed along the leeward slope. Bora is observed mainly in winter, where the mountain range borders the sea or a large body of water. The Novorossiysk forest is widely known (Fig. 95). And yet, the leading factor in climate formation in the mountains, which greatly influences all other components of nature, is altitude, leading to vertical zonation of both climate and natural zones.
Rice. 95. Scheme of formation of the Novorossiysk forest
The rivers of the North Caucasus are numerous and, like the relief and climate, are clearly divided into lowland and mountainous. There are especially numerous turbulent mountain rivers, the main source of food for which is snow and glaciers during the melting period. The largest rivers are the Kuban and Terek with their numerous tributaries, as well as the Bolshoy Yegorlyk and Kalaus, which originate in the Stavropol Upland. In the lower reaches of the Kuban and Terek there are floodplains - vast wetlands covered with reeds and reeds.
Rice. 96. Altitudinal zone of the Greater Caucasus
The wealth of the Caucasus is its fertile soils. In the western part of Ciscaucasia, chernozems predominate, and in the eastern, drier part, chestnut soils predominate. The soils of the Black Sea coast are intensively used for gardens, berry fields, and vineyards. The world's northernmost tea plantations are located in the Sochi region.
In the Greater Caucasus Mountains, altitudinal zonation is clearly expressed. The lower belt is occupied by broad-leaved forests with a predominance of oak. Above are beech forests, which with height transform first into mixed and then into spruce-fir forests. The upper border of the forest is at an altitude of 2000-2200 m. Behind it, on mountain meadow soils, there are lush subalpine meadows with thickets of Caucasian rhododendron. They pass into short-grass alpine meadows, followed by the highest mountain belt of snowfields and glaciers.
Questions and tasks
- Using the example of the North Caucasus, show the influence of the geographical location of the territory on the features of its nature.
- Tell us about the formation of the modern relief of the Greater Caucasus.
- On the contour map, indicate the main geographical objects of the area and mineral deposits.
- Describe the climate of the Greater Caucasus, explain how the climate of the foothills differs from the high-mountain regions.