Caves are formed as a result. Fairytale world of caves. Planet Earth. Caves by size

Cave - a cavity in the upper part of the earth's crust, communicating with the surface by one or more inlets. Another definition: a cave is a natural underground cavity accessible to human penetration, having unlit sunlight parts and length (depth) is greater than the other two dimensions. Most large caves- complex systems of passages and halls, often with a total length of up to several tens of kilometers. Caves are an object of speleology study. Speleotourists make a significant contribution to the study of caves.

Caves according to their origin can be divided into five groups: tectonic, erosional, ice, volcanic and, finally, the most large group- karst. Caves in the entrance part, with suitable morphology (horizontal spacious entrance) and location (close to water), were used by ancient people as comfortable dwellings.

Caves by origin

Karst caves

Most of these caves. It is karst caves that have the greatest length and depth. Karst caves are formed as a result of the dissolution of rocks by water, so they are found only where soluble rocks occur: limestone, marble, dolomite, chalk, as well as gypsum and salt. Limestone, and even more so marble, dissolves very poorly with pure distilled water. Solubility increases several times if dissolved carbon dioxide is present in water (and it is always present in natural water), but limestone still dissolves weakly compared to, say, gypsum or, moreover, salt. But it turns out that this has a positive effect on the formation of extended caves, since gypsum and salt caves not only quickly formed, but also quickly destroyed.

A huge role in the formation of caves is played by tectonic cracks and faults. According to the maps of the explored caves, one can very often see that the passages are confined to tectonic disturbances that can be traced on the surface. Also, for the formation of a cave, a sufficient amount of water precipitation is necessary, a successful form of relief: precipitation from large area should fall into the cave, the entrance to the cave should be located significantly higher than the place where groundwater is discharged, etc.

A bunch of karst caves are relic systems: the water stream that formed the cave left it due to a change in relief or for more deep levels(due to lowering of the local basis of erosion - the bottom of the neighboring river valleys), or ceased to fall into the cave due to a change in the surface catchment, after which the cave goes through various phases of aging. Very often, the studied caves are small fragments of an ancient cave system, opened up by the destruction of the enclosing mountain ranges.

Evolution karst processes and their chemistry are such that water, having dissolved mineral substances of rocks (carbonates, sulfates), after some time deposits them on the vaults and walls of caves in the form of massive crusts up to a meter or more thick (cave marble onyx) or ensembles special for each cave mineral aggregates of caves, forming stalactites, stalagmites, helictites, draperies and other specific karst mineral forms - sinter formations.

IN Lately All more caves opens in rocks traditionally considered non-karst. For example, in sandstones and table quartzites mountains tepui South America, the caves of Abismo Gai Collet with a depth of −671 m (2006), Cueva Ojos de Cristal with a length of 16 km (2009) were discovered. Apparently, these caves also have karst origin. hot tropical climate Under certain conditions, quartzite can be dissolved in water.

Another exotic example of the formation of karst caves is the very long and deepest cave in the US mainland, Lechugia Cave (and other caves in Carlsbad national park). According to the modern hypothesis, it was formed by the dissolution of limestones by rising thermal waters saturated with sulfuric acid.

Tectonic caves

Such caves can arise in any rocks as a result of the formation of tectonic faults. As a rule, such caves are found in the sides of river valleys deeply cut into the plateau, when huge rock masses break off from the sides, forming sagging cracks (sherlops). Seizure cracks usually converge with depth in a wedge. Most often they are filled with loose deposits from the surface of the massif, but sometimes they form rather deep vertical caves up to 100 m deep. Sherlops are widespread in Eastern Siberia. They are relatively poorly studied and probably occur quite often.

erosion caves

Caves formed in insoluble rocks due to mechanical erosion, that is, worked out by water containing grains of solid material. Often such caves are formed on the seashore under the action of the surf, but they are small. However, the formation of caves, worked out along the primary tectonic cracks by streams going underground, is also possible. Quite large (hundreds of meters long) erosional caves are known, formed in sandstones and even granites. Examples of large erosion caves would be T.S.O.D. (Touchy Sword of Damocles) Cave in gabbro (4 km/−51 m, New York), Bat Cave in gneisses (1.7 km, North Carolina), Upper Millerton Lake Cave in granites (California).

Glacial caves

Caves formed in the body of glaciers by melt water. Such caves are found on many glaciers. Melted glacial waters are absorbed by the body of the glacier along large cracks or at the intersection of cracks, forming passages that are sometimes passable for humans. The length of such caves can be several hundred meters, the depth - up to 100 m or more. In 1993, a giant Izortog glacial well, 173 m deep, was discovered and explored in Greenland; the inflow of water into it in summer was 30 m³ or more.

Another type of glacial caves are caves formed in a glacier at the point where intraglacial and subglacial waters exit at the edge of glaciers. Meltwater in such caves can flow both along the glacier bed and over glacial ice.

A special type of glacial caves - caves formed in glaciers at the exit point of underground caves located under the glacier. thermal waters. Hot water is capable of making voluminous galleries, however, such caves do not lie in the glacier itself, but under it, since the ice melts from below. Thermal ice caves meet in Iceland, Greenland and reach the considerable sizes.

Volcanic caves

These caves are formed during volcanic eruptions. The lava flow, cooling down, is covered with a solid crust, forming a lava tube, inside of which molten rock is still flowing. After the eruption has already, in fact, ended, the lava flows out of the tube from the lower end, and a cavity remains inside the tube. It is clear that lava caves lie on the very surface, and often the roof collapses. However, as it turned out, lava caves can reach very large sizes, up to 65.6 km long and 1100 m deep (Kazumura Cave, Hawaiian Islands).

In addition to lava tubes, there are vertical volcanic caves - the vents of volcanoes.

Caves by type of host rocks

The longest Mammoth Cave in the world (USA) is karst, laid in limestone. It has a total length of passages of more than 600 km. The longest cave in Russia - the Botovskaya cave, over 60 km long, is laid in a relatively thin layer of limestone, sandwiched between sandstones, located in the Irkutsk region, the river basin. Lena. Slightly inferior to it is Bolshaya Oreshnaya - the world's longest karst cave in conglomerates in the Krasnoyarsk Territory. The longest cave in gypsum is Optimistic, in Ukraine, with a length of more than 230 km. The formation of such extended caves in gypsum is associated with a special arrangement of rocks: the layers of gypsum that enclose the cave are covered from above with limestone, due to which the vaults do not collapse. Caves are known in rock salt, in glaciers, in solidified lava, etc.

Caves by size

Most deep caves the planets are also karst: Krubera-Voronya (up to −2196 m), Snezhnaya (−1753 m) in Abkhazia. In Russia, the deepest cave is Throat Barloga (−900 m) in Karachay-Cherkessia. All these records are constantly changing, only one thing is invariable: karst caves are in the lead.

The deepest caves in the world

The depth of a cave is the height difference between the entrance (the highest of the entrances, if there are several) and the lowest point of the cave. If there are passages in the cave located above the entrance, the concept of amplitude is used - the difference in levels between the lowest and highest points of the cave. According to estimates, maximum depth the occurrence of cave passages under the surface (not to be confused with the depth of the cave!) can be no more than 3000 meters: deeper than any cave will be crushed by the weight of the overlying rocks. For karst caves, the maximum depth of occurrence is determined by the karst base (the lower limit of karst processes coinciding with the base of the limestone sequence), which can be lower than the erosion base due to the presence of siphon channels. The deepest cave, at present, is the Krubera-Voronya cave with a depth of 2196 m, this is the first and only cave that crossed the line of 2 km. The first explored cave with a depth of more than 1000 meters was the French Berger abyss, considered the deepest in the world from the discovery in 1953 until 1963.

The longest caves in the world

Contents of the caves

Speleofauna

Although the living world of caves, as a rule, is not very rich (excluding the entrance part, where sunlight enters), nevertheless, some animals live in caves or even only in caves. First of all, these are bats, many of their species use caves as a daily shelter or for wintering. Moreover, bats sometimes fly into very remote and hard-to-reach corners, perfectly orienting themselves in narrow labyrinth passages.

In addition to bats, several species of insects, spiders (Neoleptoneta myopica), shrimp (Palaemonias alabamae) and other crustaceans, salamanders and fish (Amblyopsidae) live in some caves in warmer climates. cave views adapt to complete darkness, and many of them lose their organs of vision and pigmentation. Often these species are very rare, many of them are endemic.

archaeological finds

Primitive people used caves all over the world as a dwelling. Even more often, animals settled in the caves. Many animals died in the cave-traps, starting from steep wells. The extremely slow evolution of caves, their constant climate, and protection from the outside world have preserved a huge number of archaeological finds to us. These are pollen of fossil plants, bones of long-extinct animals (cave bear, cave hyena, mammoth, woolly rhinoceros), cave drawings ancient people (caves Kapova in the Southern Urals, Divya in the Northern Urals, Tuzuksu in the Kuznetsk Alatau, Niah Caves in Malaysia), tools of their labor (villages Strashnaya, Okladnikova, Kaminnaya in Altai), human remains of different cultures, including Neanderthals , up to 50-200 thousand years old (Teshik-Tash cave in Uzbekistan, Denisova cave in Altai, Cro-Magnon in France and many others).

The caves may have played the role of modern cinemas.

Water in the caves

Water, as a rule, is found in many caves, and karst caves owe their origin to it. In the caves you can find condensate films, drops, streams and rivers, lakes and waterfalls. Siphons in caves significantly complicate the passage, require special equipment and special training. Often there are underwater caves. In the entrance areas of the caves, water is often present in a frozen state, in the form of ice deposits, often very significant and perennial.

Air in the caves

In most caves, the air is breathable due to natural circulation, although there are caves in which you can only be in gas masks. For example, guano deposits can poison the air. However, in the vast majority natural caves air exchange with the surface is quite intense. The reasons for air movement are most often the temperature difference in the cave and on the surface, so the direction and intensity of circulation depend on the season and weather conditions. In large cavities, the movement of air is so intense that it turns into wind. For this reason, air draft is one of the important features when looking for new caves.

cave deposits

There are mechanical (clay, sand, pebbles, boulders) and chemogenic deposits (stalactites, stalagmites, etc.). IN cave systems with an active watercourse, as a rule, mechanical deposits are presented in the form of blocky blockages, often of very large volumes, formed as a result of the collapse of the set of passages that the water flow forms by dissolving. Blockages are difficult to pass, and dangerous, since the balance of a block blockage is often unstable. Clay deposits are widely represented in the galleries left by an active stream that carried mechanically insoluble rock particles. In the limestone containing the cave, the soluble component is calcium carbonate, which often makes up only about 50% of the rock. The remaining minerals are usually insoluble, and if the water that dissolves the rock is presented in the form of a drop, infiltrate, with a low water flow, unable to provide mechanical transfer of particles, clay deposits begin to accumulate. Very often, ancient passages are completely covered with clay.

Chemogenic deposits (sinter formations) also usually adorn ancient cave galleries, where water, slowly filtering through cracks in limestone, is saturated with calcium carbonate, and when it enters the cavity of the cave, due to a slight change in the partial pressure of water vapor when a drop breaks off, or when when it falls to the floor, or when turbulence occurs when draining, calcium carbonate crystallizes from a saturated solution in the form of calcite.

excursion caves

Some caves are equipped for visiting tour groups(so-called showcaves). To do this, in the part of the cave, the most spacious and rich sinter formations, pave footpaths, ladders, bridges, electric lighting is created; in some cases, if the entrance part of the cave is a technically difficult area, tunnels are made. On the territory of the former USSR, the most famous caves are Marble in the Crimea, Kungurskaya in the Urals, Novoafonskaya in Abkhazia.

Caves in the solar system

In addition to the Earth, caves have been found on the Moon and Mars. Apparently, these are volcanic caves, ancient traces of volcanic activity.

artificial caves

Caves - dungeons of the industrial world

Under any major city there is a system of dungeons for technical purposes: basements of ground buildings, metro, life support system (water supply, heating, sewerage, electrical and telephone cables, fiber optic network), bomb shelters, bunkers in case of war, and so on.

Cave - as the dwelling of holy ascetics

Many holy ascetics settled in the caves. Later, monasteries and Lavra were founded on these places:

• Kiev-Pechersk Lavra
• Pskov-Caves Monastery
• Holy Dormition cave monastery(Crimea)
• Kholkovsky Monastery
• Chelter Coba
• Basarbovsky Monastery
• Cave churches in Ivanovo

Holy ascetics who lived in caves:

• “And Lot went out of Segor and dwelt in the mountain, and his two daughters with him, for he was afraid to dwell in Segor. And he dwelt in a cave, and his two daughters with him” (Genesis 19:30)
• “And the Prophet Elijah went into the cave there and spent the night in it” (1 Kings 19.9)
• Hilarion of Kyiv
• Anthony Pechersky
• Varlaam Pechersky

cave houses

Many peoples made dwellings in caves, as they were easy to keep clean and maintain a constant temperature throughout the year.

• Cappadocia
• Anasazi
• Guadis
• Sassi Di Matera

Healing caves

In many medical institutions there are rooms called "salt caves". The walls are lined with potash salt bricks, and patients spend some time in them, listening to music and getting a healing effect.

Entertaining caves

Horror caves are known as a part of amusement parks, cafes and bars, finished under a cave.

Caves in mythology, mysticism and religion.

V. G. Ivanchenko wrote about the symbolic and mystical meaning of the caves in his article “The Sign of the Cave”, published in the journal “Orientation”.

Caves in art, literature and cinematography

Caves appear in many fantastic works (both in fantasy and science fiction). Caves (more precisely, bunkers) in science fiction mainly serve as shelters after a global catastrophe that made life on the surface impossible. And also the caves in fantasy are inhabited by: gnomes, kobolds, goblins, dragons, and in Russian folk tales"Mistress" lives there copper mountain", Dragon. In northern mythology, Sirte live in caves. One of the most famous literary characters who ended up in the caves were: Tom Sawyer along with Becky Thatcher, Bilbo Baggins.

underground cavities

In addition to caves that have access to the surface and are accessible for direct study by humans, there are closed underground cavities in the earth's crust. The deepest underground cavity (2952 meters) was discovered by drilling on the coast of Cuba. In the Rhodope Mountains, an underground cavity was discovered at a depth of 2400 meters while drilling. On the Black Sea coast in Gagra, drilling discovered underground voids at depths up to 2300 meters.

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Before answering the question “How do caves form?”, you need to understand what caves are and what they are.

Caves are empty spaces in rocks underground or under water, as well as above ground. Caves are through with several holes or with one. They are divided into horizontal, vertical, as well as inclined and single-level or multi-level. The size of the cave also varies. It happens that the cave stretches for many kilometers, rises or falls even under the water of an underground river. But the most important difference between one cave and another is the material from which they are composed, and how they were formed.

So, the largest group of caves is Karst. They are divided into marble, salt, crystal, gypsum and limestone caves, as well as others. Such caves are formed due to the dissolution of various rocks in water, and many of them have their own stalactites and stalagmites.

Evolutionists argue that the main factor that forms these caves is carbon dioxide-laden groundwater seeping through cracks along the limestone beds. This process, in their opinion, takes millions of years. But recently another factor has become known that washes out the caves much faster - this is sulfuric acid.

There are also erosive caves by water (along coastline), which are mechanically washed out by water with large grains of sand, fragments of stones, etc. Tectonic caves are formed in the sides of rivers in places of tectonic faults.

Volcanic caves appear during volcanic eruptions, when lava solidifies, creating a kind of pipe through which it flows further, forming voids. Caves in the vents of volcanoes are also volcanic. During the global flood, called Noah's Flood in the Bible, there was a worldwide volcanic activity, as a result of which many caves of this type formed very quickly.

Karst caves, photos of which can be seen in this article, are widespread throughout the world. It is for this species that formation with the greatest extent and depth is characteristic. In most cases, when caves form naturally, their shape depends on the degree of influence of water on rocks. That is why karst caves are found in those places where there are deposits of various soluble rocks.

Limestone under the influence clean water dissolves very badly. However, if the water contains an increased amount carbon dioxide, the solubility of the rock can accelerate several times.

Basic data

Karst caves are underground cavities that can form an exit to the surface or form in a closed space. In fact, they are depressions of various lengths and lengths, created naturally, without human intervention, in a variety of karst rocks. At the same time, the karst layer in each cave has its own percentage of moisture content.

It is noteworthy that salt caves are formed and destroyed quickly enough, as a result of which they almost never have time to reach the same length as limestone or marble, formed under the influence of water.

The relief of the caves

For the accelerated formation of such caves, it is necessary to have small cracks and depressions called kars in the rock layers, as well as a network of such natural holes as:

• Funnels. characteristic feature is an irregular or cone-shaped recess. They reach a diameter of up to 250-300 m at a depth of 50 m to 100 m. At the bottom, you can find special holes called ponors, into which the bulk of the groundwater. These sites are often the initial formations of future mines, wells or abysses, the depth of which in some cases exceeds a thousand meters. So, for example, one of the largest abysses in the world called Jean-Bernard is located in the Alps of France. Its depth is 1410 m.
• Basins are cavities periodically filled with water (disappearing lakes).
• Polya are hollows 20-200 km 2 in size. They are also characterized by periodic filling with water.
• Wells.
• Mines.

It is noteworthy that underground passages and depressions of various lengths initially form in karst rocks, and a full-fledged karst cave begins to gradually form from them, the formation of which can take more than one hundred years.

Education

The formation of karst caves largely depends on tectonic cracks and faults, into which large volumes of water sediments flow over a long period. In addition, for the formation of a cave, it is necessary that the entrance to it be located much higher than the place where groundwater accumulates. It is noteworthy that the main feature of karst processes is that often water, having dissolved the rock, after some time washes it back, forming a number of sinter formations.

The degree of expressiveness of karst forms

According to the degree of expressiveness, surface and underground karst formations can be divided into:

• naked - pronounced and located on the surface of the earth;
• turfed - can be covered with a layer of soil;
• covered - the karst layer is covered with loose sediments with an insoluble structure;
• armored - the karst layer is covered with semi-rock and rock formations.

Inside such caves, as a result of the lack of access to sunlight and the increased content of carbon dioxide concentration, a special microclimate has been observed for centuries, which allows preserving the natural beauty of karst formations.

Climate influence

In regions characterized by low air temperatures, underground cavities of karst caves in winter time Years freeze so much that even in summer the temperature in them does not rise above zero. In such caves one can often observe the formation of ice crust, stalactites or other forms of frozen moisture on the ceiling and walls.

Karst caves of the world

The longest cave in the world, formed in limestone, was named Mamontova. It is located in the USA (Kentucky) and has a total length of over 400 km. Two rivers flow through it at once: the Styx and the Echo.

The longest cave in gypsum - Optimistic - is located in Ukraine (Ternopil region, Podolia). It was discovered back in 1966. The length of the passages in it is more than 230 km. The area of ​​the cave itself reaches 2 hectares. This length was achieved due to the fact that the layers of gypsum in which the cave was formed are covered from above with a layer of limestone, which keeps the vaults from collapsing.

It is noteworthy that the deepest caves in the world are also karst. An example is the Abkhaz: Krubera-Voronya and Snezhnaya. The depth of the first is 2191 m, and the second is 1753 m.

A large number of karst caves are also found in Europe. The most famous of them is the Moravian Karst ( Czech Republic). Its underground karst deposits of Devonian limestone formed over 350 million years ago. It represents a whole area of ​​karst subsidence.

At the same time, one of the most popular caves among tourists remains the Postojnska Yama karst cave (Slovenia). Its total length is no more than 20 km, however, the Poika River flows through its underground territory, in the waters of which you can see unusual whitish fish without eyes.

Karst caves in Russia

Despite the variety of karst caves around the world, the largest and longest of them - Bolshaya Oreshnaya - is located in the Krasnoyarsk Territory.

One of the longest limestone caves in Russia - Botovskaya ( Irkutsk region). Its length is about 60 km.

The deepest karst cave, Gorlo Barloga, is located in Karachay-Cherkessia and goes 900 m deep.

Caves of the Crimean Peninsula

Special attention should be paid to the Crimea, which has long been famous for its karst cavities.

Despite the fact that their formations occupy an impressive part of the peninsula, karst caves such as:

1. Red. The labyrinths of its passages occupy 6 floors with a vault height of about 30 m and a length of halls up to 80 m. It accounts for 1/3 of the area of ​​all formations of this type on the peninsula. The underground river Su-Uchkhan flows along the bottom of the cave, the vaults of which are decorated with extremely beautiful columns, stalagmites and stalactites.
2. Marble is located at an altitude of 1000 m above sea level. It got its name as a result of formation in marbled limestone. It contains the most beautiful cascades of lakes, placers of cave pearls and stone waterfalls.
3. Emine-Bair-Khosar occupies one of the first places among the world natural phenomena. It represents more than 1500 galleries and halls, a small fraction of which is equipped for visiting tourists. In this cave, you can see a unique collection of the remains of representatives of the wild fauna that inhabited the Crimean peninsula several million years ago.

Research features

Underground waters gradually wash out and widen the cracks in the rock and begin to form galleries and grottoes. It is noteworthy that those karst caves, where water flows make more impressive paths for themselves, gradually expand and form an intricate system of underground passages, which can be located at various levels and connected by mines and wells of various depths.

Any person who decides to travel along the underground river must always remember that this is a very dangerous occupation. Although most of The tunnels are quite wide, in certain areas they gradually narrow. At the same time, under the influence of the current, the boat can simply crash against the walls of the cave. In addition, tourists in such suits are also waiting for numerous rapids and waterfalls, as well as unexpected deep abysses. You can also get serious injuries by bumping into natural growths of rock: both protruding from the water and hanging from the ceiling. As a result, you can be knocked off the boat into icy water, which is fraught with not only bruises, but also hypothermia. That is why, when exploring karst caves, it is necessary to exercise utmost care and caution in order to preserve only pleasant impressions from unforgettable trip these wonderful places.

LITERATURE

CAVES CLASSIFICATION, KARST PHENOMENA AND CAVEL FORMATION

TYPES OF CAVES

There are caves (in terms of origin - speleogenesis):

- natural (karst, etc.),

- artificial (anthropogenic - catacombs, quarries; examples: near Moscow: Silicates, Syany, Kiseli, Volodar, Nikita; in Crimea: Sevastopol, Kerch; in Odessa: Odessa). There are underground cities and temples: Chufut-Kale (Bakhchisaray, Crimea), Kiev Pechersk Lavra, etc. There are also modern underground structures and communications - they are dealt with by "diggers" - they are not speleologists.

Natural caves are:

- karst (in karst rocks),

- underground cavities in non-karsting rocks associated with mountain building processes (tectonic processes).

Cavities in non-karsting rocks :

- niches, cracks, faults and faults hidden or having access to the surface in granites, basalts, diorites and other water-insoluble rocks, which were formed during the movement of the earth's crust. These are very rarely observed small cavities, usually filled with water.

- caves of volcanic origin: tunnels and corridors in frozen lava flows - from above, lava cools and hardens faster in contact with air, inside it flows, forming cavities. Speleology is mainly concerned with karst caves.

Karst caves

Word karst- distorted Slovenian (and Slovak) word KRAS - proper name - name mountainous area in Slovenia, where there are many caves. Other caves of this type began to be called by this name. Karst rocks are the rocks that make up the upper part of the earth's crust, which, to one degree or another, can dissolve in water (they are subjected to leaching).

The main karst rocks:

- Limestone - calcium carbonate Ca2CO3,

- Dolomite is a mixture of limestone with magnesium carbonate Mg2CO3,

- Gypsum - calcium sulfate Ca2SO4,

- Rock salt NaCl,

Ice H2O.

There are also various subspecies of karst rocks that are mentioned in the literature (and, of course, are found in practice):

- marl limestones (include aluminosilicate deposits, alumina),

- conglomerates (mixtures of karst and non-karst rocks), etc.

About limestones, as the most common karst rock:

They come in different ages: Cambrian, Permian, Jurassic, Cretaceous, etc.

In addition, limestones are:

- massive (clean) - these karst well,

- layered (large and small) - these karst the worse, the finer the layer,

- marbled (recrystallized) - karst worse.

The two classic karst rocks are limestone and gypsum. These rocks are often referred to as sedimentary, which emphasizes their supposed origin: the result of biogenic sediment in the waters of ancient seas.

HYPOTHESIS ON THE ORIGIN OF KARST REGIONS

Namely, there is a hypothesis that:

- in ancient times, 300-400 million years ago, a process of growth and death of living organisms took place in sea water, intensively using calcium to build their shells. The water was a saturated solution of calcium carbonate. Dead shells sank to the bottom and accumulated along with sediments precipitating out of solution as a result of climatic changes;

- for millions of years, limestone mass accumulated at the bottom in layers;

- under pressure, the limestone sediment changed its structure, turning into a stone lying in horizontal layers;

- at the moment of movements of the earth's crust, the sea receded, and the former bottom became land;

- Two scenarios were possible for the development of events: 1) the layers remained almost horizontal and untorn (as near Moscow) PICTURE 5.and 2) the bottom protruded forming mountains, while the integrity of the limestone layers was violated, numerous transverse cracks and faults formed in them. PICTURE 6. This is how the future karst area was formed.

This hypothesis is confirmed by the finds of the remains of ancient shells and other former living organisms in the thickness of limestones. Be that as it may, it is obvious that the caves and the rocks where they form are closely connected with ancient life on Earth.

CONDITIONS FOR THE FORMATION OF CAVES.

There are three main conditions for the formation of karst caves:

- Presence of karst rocks.

- The presence of mountain building processes, movements of the earth's crust in the zone of distribution of karst rocks, as a result - the presence of cracks in the thickness of the massif.

- Presence of aggressive circulating waters.

Without any of these conditions, cave formation will not occur. However, for these the necessary conditions local features of the climate, the structure of the relief, the presence of other rocks can be superimposed. All this leads to the appearance of caves. different kind. Even in one cave there are various "composite" elements that are formed in different ways. The main morphological elements of karst caves and their origin.

Morphological elements of karst caves:

- vertical abysses, shafts and wells,

- horizontally inclined caves, and meanders,

halls,

Labyrinths.

These elements arise depending on the type of disturbances in the thickness of the karst massif.

Types of violations:

1. Faults and faults,

2. Cracks:

bedding,

- on the border of karst and non-karst rock,

- tectonic (usually transverse),

- so-called lateral cracks.

Scheme of the formation of vertical elements of caves (wells, mines, abysses):

Leaching.

Wells are formed at the intersection of tectonic cracks - in the most mechanically weak point of the massif. This is where precipitation water is absorbed. And slowly dissolves the limestone; over millions of years, water expands cracks, turning them into wells. This is a zone of vertical circulation of groundwater.

Nival wells(from array surface):

In winter, the cracks are clogged with snow, then it slowly melts, this is aggressive water, it intensively erodes and expands the cracks, forming wells from the surface of the earth.

Formation of horizontally inclined passages:

Water, penetrating through the layer (layer) of karst rock, reaches the bedding crack and begins to spread along it along the plane of the "fall" of the layers. There is a process of leaching, a subhorizontal course is formed. Then the water will reach the next intersection of tectonic cracks and again a vertical well or ledge will form. Finally, the water will reach the border of karsting and non-karsting rocks and then spread only along this border. Usually an underground river is already flowing here, there are siphons there. This is a zone of horizontal circulation of groundwater.

Hall formation.

The halls are found in fault zones - large mechanical disturbances in the massif. The halls are the result of alternating processes of mountain building, leaching, and again mountain building (earthquakes, landslides).

It happens that additional mechanisms are included:

- mechanical removal of rock fragments by water flows,

- the action of pressure thermal waters (New Athos cave).

Formation of horizontal labyrinths.

The leaching process occurs along a "grid" of tectonic cracks. A typical example is gypsum caves. Western Ukraine. The named mechanisms of formation of structural elements (morphology) of caves are common for all types of karst rocks.

In general, we can say that the karst massif is a "sieve" that sifts through precipitation and flowing waters. All karst caves - both vertical and horizontal - are channels for the natural drainage of water in the karst massif. The result of this circulation is the indispensable release of groundwater to the surface - in the form of obvious or hidden sources, including submarine ones.