Karst caves. What is karst and karst caves

What is the meaning of the words "karst cave"? How did these beautiful natural objects form? You can find answers to these questions in this article. In addition, here we list the longest in the world (you can also see photos of these underground voids). Curiously, most of them are located in the United States.

A cave is ... The meaning of the words "karst cave"

These underground cavities from the most ancient times served as a dwelling for animals, as well as primitive people. They hid them from the cold and wild predators. Interestingly, caves have been found not only on Earth, but also on the Moon and Mars. Let us first find out the meaning of the words "karst cave".

This phrase consists of two parts: "cave" and "karst".

• A cave is any underground cavity of natural origin.
• Karst is both a process and a result of the destruction (dissolution) of certain rocks by aggressive (in terms of chemical composition) groundwater.

The term "karst" itself comes either from the German word karst, or from the name of a plateau in Slovenia (Kras), where these natural phenomena are most pronounced.

What is a karst cave?

This type of caves is the most common among all other underground cavities. What is a karst cave and how is it formed?

There are two main definitions. According to the first, it is a natural cavity (emptiness) in the upper part of the earth's crust, which is connected to its surface by one or more entrances. According to the second definition, a karst cave is an underground cavity of natural origin, which is not illuminated by the Sun, but is accessible to penetration from the outside.

The study of caves is carried out by a special science - speleology, the material for which is often mined by the so-called speleologists.

How are karst caves formed?

Caves of this type are formed due to, namely, due to the dissolution of rocks by water. It should be noted that karst caves are present only in those areas of the Earth where unstable rocks occur, which are easily dissolved by water. Among these are gypsum, salt, chalk (kaolin), dolomite, marble and limestone.

Worse than all the others, limestone and marble are destroyed. Caves in these rocks are formed for a very long time. On the other hand, they are better preserved than others. For example, gypsum caves very often collapse and collapse.

An important role in the formation of underground voids is played not only by the chemical composition of water (it should contain an increased concentration of carbon dioxide), but also by the presence of cracks and extended faults in the earth's interior. They, as a rule, are those axial lines along which the caves are formed.

Most of the studied caves are relic type systems. This means that the water has already left these underground cavities. Nevertheless, it is she who acts as the sculptor who forms the internal "micro-relief" of the cave. saturated with sulfates and carbonates, deposits them on the walls, floors and vaults of underground cavities. This is how what we call is formed. Very often, these growths take on strange and bizarre forms that look even more unusual in the darkness.

Main types of caves

According to the mechanism of genesis (formation), in addition to karst, there are also tectonic, volcanic, erosional, and glacial caves.

Underground cavities are also classified by size (by total length and depth), as well as by the type of rocks in which they are formed. So, there are caves:

• limestone;
• plaster;
• chalky;
• salt;
• caves in conglomerates and so on.

TOP 5 longest caves on the planet

Four of the five longest caves in the world are located in the United States, and one more is in Ukraine.

(about 630 km) - the longest cave system on Earth. It was formed in limestone 10 million years ago. Every year the length of the cave increases, as speleologists explore its new corridors.

Jewel Cave (257 km) - located near the city of Custer. Its unique feature is calcite crystals, which cover the walls of all underground corridors in a thick layer.

Cave Optimisticheskaya (231 km) - a multi-level network of labyrinths in Ukraine (in the Ternopil region), the largest underground system in Eurasia. Formed in gypsum.

Wind Cave (217 km) is another American wonder of nature, which is known for its honeycomb-like patterns on the vaults.

Lechugia Cave (207 km) is a gypsum cave in the USA (New Mexico), whose hallmark is unusual "chandelier" formations, reaching up to 5-6 meters in diameter.

Conclusion

Well, now you know the meaning of the words "karst cave". This is an underground cavity of natural origin, which has one or more exits to the surface. All caves are classified by speleologists according to size, mechanism of genesis, as well as according to the rocks in which they are laid (formed).

One summer I found myself in a cave for the first time, and in the famous cave of Petralona, ​​located in northern Greece. This cave is of great importance in the field of anthropology and paleontology - it is here, according to Greek scientists, that the skeleton of the oldest Neanderthal man in Europe, who lived in Europe more than 700 thousand years ago, was found. And since then, the question of the cradle of humanity, where humanity nevertheless originated, has been controversial, despite numerous studies and collected evidence.

But most of all, this Greek cave struck me with its size and beauty. Here I first saw a cave lake, stalactites, stalagmites and stalagnates. Passing from hall to hall of this cave, I thought how it happens that “icicles” - stalactites - hang from above. Why do they have such bizarre shapes and do not melt? And below, like trees, other “icicles” grow - stalagmites. What do they grow out of if there are stones around? Why don't they fall? Why are they both hard and brittle at the same time, but wet to the touch? What if you grow a stalagmite or stalactite at home and decorate your room? Or such a curiosity can be useful in everyday life?

After returning home, I decided to investigate this issue. And I had to start with studying the “habitat” of these amazing cave formations - from the caves themselves. There was also a lot of interesting and exciting here. I still had the initial idea and information after visiting the Greek cave. Our guide was very interesting and told in detail about the cave in which I was. But how are the caves themselves born? And why exactly in them, and nowhere else, do stalactites and stalagmites appear? What are these stalactites made of?

In the course of my research, in order to solve the tasks set, I had to study scientific articles and the results of speleological research. Speleology is a science that deals with the study of caves. In addition, I decided to conduct an experiment on growing a stalactite at home.

And in order to understand the nature of stalactites and stalagmites, first I needed to learn everything about caves - what are they and how do they form? I found the necessary theoretical information in encyclopedias and on Internet sites.

Caves. Their education.

A cave is a natural cavity in the upper thickness of the earth's crust, which communicates with the earth's surface by one or more outlets passable for a person. The largest caves are complex systems of passages and halls, the total length of which often reaches several tens of kilometers. Caves are an object of speleology study.

Caves have long been associated with the history of human development. Even in the Stone Age, caves saved people from the winter cold. But even after the ancient people stopped using the caves as dwellings, the caves were surrounded by an aura of the unusual and strange. The Greeks believed that the caves were the temples of their gods - Zeus, Pan, Dionysius and Pluto. In ancient Rome, it was believed that nymphs and sorceresses lived in caves. The ancient Persians and other peoples believed that the king of all earthly spirits, Mithras, lives in the caves. Today, the vast and beautiful caves attract tourists.

In nature, there are no two identical caves. Caves form in different ways. However, all the largest caves in the world are formed in a similar way. Some large caves began to be created 60 million years ago. Rains poured down, rivers overflowed, and monolithic mountains slowly collapsed, and large voids appeared inside the hills, mountains and rocks (Appendix 1).

The rock in which the caves arise is limestone. This is a soft rock, it can be dissolved by weak acid. The acid that breaks down limestone comes from rainwater. Falling raindrops take carbon dioxide from the air and soil. This carbon dioxide turns water into carbon dioxide.

Therefore, acid rain watered limestone for millions of years. They constantly dripped onto the mountains, and cracks began to appear on them. And the rains continued to pour. The water flowed, widening the cracks. She found new cracks in the monolith. The cracks widened into tunnels. Tunnels crossed, niches appeared. After millions of years, the caves took their shape. And the water made the caves bigger and bigger.

Some caves have holes in the ceiling (Appendix 2). They formed in the place where water once accumulated, which then broke into the cave. In the caves you can find rows of galleries going one above the other. Streams of water flow through some caves, in others - after their formation, the water goes down, and the cave dries up.

Caves are hidden everywhere: in the mountains, just in stony soil, composed of soft rocks. Caves are built not only by water, but also by wind, sea surf, and volcanic lava. Caves remain after the extraction of rock salt. There are also ice caves, only they are short-lived.

Types of caves.

The caves can be divided according to their origin into five groups. These are tectonic, marine, glacial, volcanic and, finally, the largest and most common group, karst caves.

Tectonic caves can occur 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 massifs of rock break off from the sides, forming cracks (sherlops), which in turn usually converge with depth like a wedge. Sometimes they form rather deep vertical caves up to 100 m deep. This type of caves is widespread in Eastern Siberia.

Sea caves arose under the influence of splashing waves on stone cliffs along the coast (Appendix 3). Sea waves containing grains of solid material (pebbles, fine sand) dissolved the cliffs. They were destroyed, undermined from year to year by the surf. Separate caves are located under water. They are usually the result of the activity of groundwater, washing out soft rocks, for example, the same limestone.

Glacial caves are found in many glaciers and are formed inside the glaciers by melt water (Appendix 4). Glacial melt water is absorbed by the glacier along large fissures or at the intersection of fissures. At the same time, passages are formed along which a person can sometimes pass. Such caves have the shape of a well and reach a depth of 100 meters or more. In 1993, a giant glacial well "Izotrog" with a depth of 173 meters was discovered and explored.

A special type of glacial caves are caves formed in a glacier at the point where underground thermal waters come out. Since the water is hot, it is able to make voluminous galleries. Such caves are located not in the glacier itself, but under it, since the ice melts from below. Thermal glacial caves are found in Iceland, Greenland and reach considerable sizes.

Volcanic or lava caves occur during volcanic eruptions (Appendix 5). 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, lava caves can reach very large sizes. Such, for example, as the Kazumura Cave in Hawaii - 65.6 km long and 1100 m deep. And the largest volcanic cave in the world Cueva de Loe Verdes is located on one of the Canary Islands.

Karst caves are the majority of such caves (Appendix 6). It is karst caves that have the greatest length and depth.

Caves are formed due to the dissolution of rocks by water. Therefore, karst caves are found only where soluble rocks occur: limestone, marble, chalk, 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 in nature it is always dissolved in water. However, all the same, limestone dissolves poorly, compared, say, with 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 form, but also quickly collapse.

Caves are a special world that has no analogues on the surface. There is neither winter nor summer in the caves. The temperature is always the same. In cold caves, it ranges from +2 to +8 degrees, and in warm and hot - from +15 to +28.

It turns out that the air in the caves is sterile. It has a thousand times fewer germs than on the surface. It turns out that radioactive isotopes of carbon penetrate into the caves along with underground waters. They cause the glow of stalactites, ionize the air, kill microbes.

The longest cave in the world - Flint Mammoth - is located in the USA, in the state of Kentucky. The length of all its corridors is more than 550 kilometers. And the deepest cave is located in Abkhazia - the cave of Krubera-Voronya. A person can go down to 2 kilometers into it.

Despite the fact that so much is already known about caves, more discoveries lie ahead of scientists. Each cave has passages, crevices and corridors that cave travelers - speleologists - do not yet know about. They think that they have already studied everything, but suddenly one day they notice a gap behind a stone blockage, and behind it is a corridor, beyond which there are several more meters of cave beauty.

As a result of these studies, it can be concluded that there are several types of caves, but the most common are karst. For the formation of a cave, a sufficient amount of water precipitation and a successful form of relief are necessary, that is, precipitation from a large area must fall into the cave, and the entrance to the cave must be located noticeably higher than the place where groundwater is discharged.

Stalactites, stalagmites and stalagnates

Water is a great power. She grinds stone when she makes her way, she builds galleries, and then she leaves them, undermines rocks, and they sink, collapse, move. This is how the caves themselves are born. However, water is not only a builder, but also an artist, a sculptor!

Caves are in different rocks, and water brings different particles into them, builds from different materials: from calcite, gypsum, rock salt. The dissolution and destruction of sedimentary rocks by water is called karst - the karst process.

The karst process is two-faced: water dissolves rock in one place, transfers it to another, and there it creates beautiful sinter formations from the same rock - stalactites and stalagmites.

Stalactites (from the Greek stalaktós - dripping drop by drop) are drip-drop formations hanging in the form of conical icicles, draperies, curving fringe or hollow tubes from the vaults and upper parts of the walls of karst caves or other underground voids (Appendix 7).

Stalagmites (from the Greek stálagma - drop), drip-and-drop formations of columnar, conical and other shapes, rising from the bottom of caves and other underground karst cavities (Appendix 8).

Stalagnates are sag-drop formations in the form of columns that appear in caves when stalactites and stalagmites join (Appendix 9).

How are they formed? A raindrop, seeping through a crack in the rock, dissolves a piece of stone. Thus, each such drop contains particles of limestone or other minerals. By dissolving limestone, water takes away the mineral calcite from it. A drop of solution saturated with calcite through the smallest cracks reaches the ceiling of an already created cave and hangs on it (Appendix 10).

Gradually, very slowly, the drop evaporates, and the piece of calcite or other mineral brought by it with the thinnest film settles on the ceiling. After some time, the next droplet comes to this place and again deposits calcite. Growing, grains of calcite first turn into a thin transparent and empty tube inside. Why empty? Yes, because the drop itself is empty inside.

But then a grain of sand gets into the drop and clogs the tube. Then other drops begin to flow around this tube from all sides, and a stone icicle grows, the same as the ice one - a stalactite.

But the drops come unevenly from one side or the other, and the stalactite is not quite round. And then it rains on the surface, the water becomes dirty, the stalactite darkens. The rain has stopped, the water is clear again, and the next layer of stalactite has become a different color. If you cut it, then the cut will have the same rings as a tree, but not annual ones. It's just that in spring and autumn there is more water, and the stalactite grows faster. The water is darker, and the ring is darker, there is less water, and growth has stopped (Appendix 11).

I even found the chemical formula for the formation of a stalactite. Here it is: CaCO3 + H2O + CO2 Ca2+ + 2 HCO3

But not all calcite settles on the ceiling and gives growth to the stalactite. Under their own weight, some of the drops fall to the floor, and a stalagmite grows from below towards the stalactite. When a stalactite and a stalagmite join and grow together, a calcite column is formed - a stalagnate. And stalactites, and stalagmites, and columns are very large - tens of meters in height and several meters in diameter.

Water drops, falling on them, form streams that flow around the columns from all sides, and then there are streaks in the form of ribs. If the drops flow down the wall of the cave, then no less amazing streaks appear on it in the form of stone waterfalls, flags and other fantastic formations.

Sometimes streaks of completely unexpected forms appear in the caves. Stalactites suddenly begin to grow at random, creating bizarre stone weaves. Surprisingly beautiful stone and gypsum stalactite flowers appear on the floor and on the walls - corallites, crystallictites and helictites (Appendix 12).

Where there is an imbalance in the flow of the solution - for example, it drips from above, but so little that the drops immediately spread like a film - hybrid forms arise, the stalagmite blooms with a bush. In this case, a wide variety of transitional forms, polymineral forms, and much more arise. For example, you can find formations that exactly copy the architecture of wasp nests. And the gypsum web, which is thinner than a human hair, crumbles into dust at the slightest fluctuation of air.

Billions of drops over millions of years have created in the cave a whole forest of stalactites, stalagmites, fantastic interior decoration of columns and openwork stone curtains, flags and waterfalls (Appendix 13).

On the floor of the cave, flowing water also deposits calcite and forms "baths" that vary in shape and color. The smallest particles of salts of various minerals and metals - copper, cobalt, iron - make the stains pink, yellow, blue, red, carrot, black. Very rarely found in the "baths" the so-called cave pearls. It is formed in the same way as the sea, but not in the shell. Sometimes cave pearls reach three to five centimeters in diameter - almost like a ping-pong ball - but this is very rare.

A wide variety of stalactites can be found in karst caves. For example, tubular stalactites, they are pasta. The channel, which runs along their entire length, for centuries automatically suggested to researchers that the stalactite is fed through this channel. But it turned out that this was not the case at all. It turned out that the channel is just a consequence of crystallization along the perimeter of the detached drop. That is why new stalactites, growing in place of the broken ones, do not continue the original pipe, but grow slightly to the side, where it is more convenient for water to drip.

The most spectacular of the stalactites are draperies (Appendix 14) that appear on sloping walls. It is then that the growing stalactite begins to influence the point of separation of the drop, and it becomes mobile, moving along the slightest whim of the water stream and fixing in its dashingly swirling form the direction of these jets, where they should flow.

When a mineral changes, say, calcite to gypsum, the cave also changes, and beyond recognition (Appendix 15). Gypsum has a different crystallization chemistry. Therefore, in such a cave, gypsum formations “grow” - “crystal chandeliers” (Appendix 16) and gypsum “snow-covered firs”.

They form in an extremely remarkable way. The cave also has dry and wet seasons, and gypsum is a highly soluble mineral. When moisture settles on the surface, the gypsum dissolves. When the moisture evaporates, the gypsum crystallizes. Water "likes" to settle in depressions, and to evaporate from ledges is elementary physics. And then it turns out that the inner cavity of the stalagmite continues to dissolve, and the outer surface - to grow, moreover, branched bushes of crystals. Those same “snow-covered firs” appear. When the wall becomes thinner so that the stalagmite no longer holds its own weight, then “dying”, it falls into itself, providing its own “reserves” of gypsum for the growth of other formations.

It takes a lot of time to create all this extraordinary underground beauty. Scientists have calculated that, on average, a stalactite grows by four tenths of a millimeter per year and grows by only four centimeters in a hundred years. And in 100 years, a stone icicle will appear at this place - a stalactite 4 centimeters long. And every 100 years, the stalactite will grow by the same amount. And below, where the drop fell, a stone tower will grow - a stalagmite. After millions of years, the stalactite and stalagmite will unite and turn into a sparkling column. This means that a man who broke a meter-long stone icicle destroyed what nature had been creating for about two and a half thousand years!

Thus, in the course of the study, I learned that stalactites, stalagmites and stalagnates are drip-leak formations in caves. The process of formation of stalactites and stalagmites is a complex chemical process, which consists in the fact that water dissolves the rock, transfers it to another place and after a while deposits it back, creating sinter formations. This process takes hundreds, thousands of years.

Other mysteries of the caves

Paleontology is the science that studies fossil plants and animals. Fossils are the remains of animals that lived millions of years ago, which have survived to this day. It is mainly through the study of fossils that we know what the animal world was like hundreds of millions of years ago.

At the beginning of my work, I already said that the study of caves is of great scientific importance in paleontology, mineralogy, anthropology, and archeology. This is confirmed by the loudest and most interesting discovery of the 20th century - the discovery of the Petralona cave in northern Greece. I myself was in this cave, and it became the starting point for me in studying the mechanism of formation of caves and stalactites. Therefore, I want to briefly talk about it (Appendices 17-24).

In 1959, on the peninsula of Chalkidiki, in northern Greece, at an altitude of 250 meters above sea level, at the foot of Mount Katsika, an entrance to a cave was discovered. It all happened quite by accident, a shepherd named Petralona was tending sheep in the area. Once, having heard the quiet murmur of water, I decided to carefully examine the foot of the mountain and stumbled upon the entrance to the cave. Further research was undertaken by specialists, in particular the famous Greek anthropologist Aris Poulianos, who later built a paleontological museum next to the cave and even sometimes conducts excursions himself. I was lucky, I also saw him when I was on a tour.

The area of ​​the cave is 10 thousand square meters, the total length of the corridors (passages) is 1,500 meters. The tourist route, open to the public, is still only 600 meters. The finds that were discovered inside this cave made a real revolution in anthropology. In 1960, a year after the discovery of the cave itself, a skull and skeleton of an ancient European, a Neanderthal man, called archanthropus, was discovered inside. The results of the first study of the skull were presented at the International Congress of Anthropologists in Moscow in 1964 and made a great impression on specialists.

In addition, petrified bones, stone tools, animal remains - bears, hyenas, turtles, rhinos, lions and even a giraffe were found in the cave. And another unusual find from the Petralona cave is traces of fires and ash, which is 1 million years old. According to scientists, these are the oldest traces of the use of fire by man.

Until recently, it was believed that the age of mankind is 3.5-4 million years, and Africa is the homeland. However, the finds from the Petralone cave and their dating give the right to assume that the cradle of mankind is South-Eastern Europe, and man appeared 11-12 million years ago in Greece. All finds from the Petralona cave are exhibited in the anthropological museum built next to the cave.

In fact, there are a lot of mysteries and mysteries in the caves. As I found out in the course of my research, the animal world of the dungeons is unusual and interesting. Even primitive man knew and painted on the walls of animals that lived in caves - a cave lion, a hyena, a cave bear. By the way, rock paintings also carry a lot of interesting information for scientists (Appendix 25).

Ancient animals died out long ago, people left the caves, but the caves themselves were not empty. Serious biological research into the underworld began only in 1831, when the first cave beetle was found. Since then, many different cave creatures have been discovered - both aquatic and terrestrial. These are troglobionts, which means "living in caves" - crustaceans, fish, wood lice, centipedes, spiders, false scorpions and other insects.

The adaptation of living organisms to cave life is very complex and diverse. Compared to their terrestrial relatives, they have longer and thinner bodies, more elongated legs and antennae, they are transparent and colorless. Since there is no light in the caves, they do not need sight, and therefore they do not have eyes. In the caves there are blind beetles, fish, amphibians, crayfish and even blind and wingless flies. The air in the caves is saturated with moisture, and therefore troglobionts can live both in water and on land.

According to scientists, animals and insects went into the caves due to climate change on Earth, namely during a cold snap. Thus, the majority of modern cave dwellers are representatives of past eras, living fossils that are no longer found on the surface, but have retained the appearance and habits of bygone millennia.

However, most lovers of the dark spend only part of their lives underground. For example, butterflies only hibernate in caves. And some species of grasshoppers, leading a nocturnal lifestyle, are there all day. The cave bear also belonged to them, because the cave was for him only a place of rest. The hyena and the lion spent even less time in the caves. Unlike the cave bear, they never went far into the depths of the cave, but stayed at the entrance.

Treasures of the caves - another mystery and mystery of the caves. For many millennia, legends and tales have been talking about treasures hidden in caves. Under the ground, more than once, the bones of lost treasure hunters were found, who never managed to find the treasured treasures. One of the caves in the Czech Tatras is called the Cave of the Treasure Seekers. And how many legends are made about pirate treasures hidden, including in caves. But in every legend there is some truth.

CONCLUSION

The object of my research was the caves and their mysteries, the main of which are stalactites, stalagmites and stalagnates, the mechanism of their formation and the possibility of creating in domestic conditions, that is, at home. At the beginning of the work, I intended to conduct an experiment on such cultivation. I thought that by studying the nature and mechanism of stalactite formation, I could do the same myself. But even in the course of theoretical research, I realized that it is impossible to grow a real stalactite at home.

In order to grow a stalactite, several very essential conditions are required. Namely - a cave with a certain relief and microclimate, a constant flow of water, the presence of carbon dioxide, and most importantly - several hundred and even thousands of years. Human life is not enough to repeat such an unusual and beautiful phenomenon as a stalactite or stalagmite. There is only one thing left - to admire and cherish.

Based on the results of my research, I can draw the main conclusion - there are such natural phenomena that a person should study, protect, but it is not at all necessary to repeat them or use them in his life. Perhaps someday people will invent a time machine or a time accelerator and then they will be able to artificially accelerate the natural process of stalactite growth, but the next question arises, is it necessary?

Why do I need this knowledge? Can they be useful to me in life? I think yes. And mainly, in order to better understand the world around us, to see and appreciate the beauty that nature can create. And yet - suddenly the climate on the Planet will change dramatically again and people will again have to return to the caves. With this knowledge, it will be easier for me to get used to it myself and help others.

Moscow State Institute of Steel and Alloys

Vyksa Branch

(University of Technology)

Subject abstract

crystal physics

On the topic: "The formation of caves and karsts"

Student: Pichugin A.A.

Groups:MO-07 (MChM)

Lecturer: Lopatin D.V.

Moscow 2008

I. General information about caves and karsts

II. Hypothesis about the origin of karst areas

III. Conditions for the formation of caves

IV. Types of caves:

1. Karst caves

2. Tectonic caves

3. Erosion caves

4. Glacial caves

5. Lava cave

V. Caves in the territory of the Baikal region

VI. Cave Kyzylyarovskaya them. G.A. Maksimovich.

General information about caves and karsts

Karst(from German Karst, after the name of the limestone alpine plateau Kras in Slovenia), - a set of processes and phenomena associated with the activity of water and expressed in the dissolution of rocks and the formation of voids in them, as well as peculiar landforms that arise in areas composed of relatively easily water-soluble rocks (gypsum, limestone, marble, dolomite and rock salt).

Negative landforms are most characteristic of karst. By origin, they are divided into forms formed by dissolution (surface and underground), erosive and mixed. According to morphology, the following formations are distinguished: karrs, wells, mines, dips, funnels, blind karst ravines, valleys, fields, karst caves, underground karst channels. The following conditions are necessary for the development of the karst process: a) the presence of a flat or slightly inclined surface so that water can stagnate and seep in through cracks; b) the thickness of karst rocks must have a significant thickness; c) the groundwater level should be low so that there is sufficient space for the vertical movement of groundwater.

According to the depth of the groundwater level, deep and shallow karst are distinguished. There is also a distinction between "bare", or Mediterranean karst, in which karst landforms are devoid of soil and vegetation cover (for example, the Mountainous Crimea), and "covered" or Central European karst, on the surface of which weathering crust is preserved and soil and vegetation cover is developed.

Karst is characterized by a complex of surface (craters, karrs, gutters, basins, caverns, etc.) and underground (karst caves, galleries, cavities, passages) relief forms. Transitional between surface and underground forms are shallow (up to 20 m) karst wells, natural tunnels, mines or failures. Sinks or other elements of surface karst through which surface waters enter the karst system are called ponors.

Karst, limestone plateaus - a complex of irregularities, convex outcrops of rocks, depressions, caves, disappeared streams and underground drains. Occurs in water-soluble and weathered rocks. The process is typical for limestone, as well as for those places where rocks are washed out. Many rivers are underground, there are also many caves and large caverns. The largest caves can collapse and form a gorge or gorge. Gradually all the limestone can be washed away. The phenomenon is named after the Karst plateau in the former Yugoslavia. Characteristic karst systems are widely represented in the Crimean mountains and in the Urals.

Karst can be observed in the Western Alps, in the Appalachians (USA) and in southern China because the limestone rock layers, which first consisted of a layer of calcite (calcium carbonate), up to 200 m thick, which was partially eroded by water. Carbon dioxide from the atmosphere was dissolved in the rain and contributed to the formation of weak carbonic acid, which in turn contributed to the erosion of rocks, especially along cleavage lines and layers, increasing them to the formation of karst caves, valleys that arose as a result of the collapse of cave walls, which, with further development processes can turn into gorges, and, finally, remains of limestone, characteristic of the karst landscape, that have not been eroded, remain.

Cave- a natural cavity in the upper thickness of the earth's crust, communicating with the earth's surface by one or more outlets passable for a person. The largest caves are 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.

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

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;

Over 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 shifts in the earth's crust, the sea receded, and the former bottom became dry land;

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

1. The presence of karst rocks.

2. 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.

3. Presence of aggressive circulating waters.

Without any of these conditions, cave formation will not occur. However, these necessary conditions may be superimposed by local features of the climate, the relief structure, and the presence of other rocks. All this leads to the appearance of caves of various types. 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,

Labyrinths.

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

Types of violations:

Faults and faults, cracks:

bedding,

On the border of karst and non-karst rock,

Tectonic (usually transverse),

The so-called lateral resistance 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 the surface of the massif):

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 moves:

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,

Action of pressure thermal waters (New Athos cave).

Karst is understood as a geological process and related phenomena that develop as a result of the interaction of water with soluble rocks. These include zones in which the properties of rocks change, surface and underground karst forms, and karst deposits.

In the zones of changes in the water-physical and physical-mechanical properties of rocks, disintegration, brecciation, vugginess and deconsolidation of rocks occur. On the surface of soluble rocks, negative corrosion forms are formed - niches, karr, funnels, hollows, fields, ditches, karst logs, ravines, valleys and canyons. Niches are recesses of various shapes and genesis on the slopes of karst massifs. Carr are microforms in the form of grooves, grooves, holes on horizontal or vertical surfaces of rocks. Closed, rounded, oval or irregularly shaped depressions up to 100 m in diameter, widening upwards, form funnels, and more than 100 m in diameter form depressions. Polya are closed or semi-closed forms of various sizes (up to 500 km2 in area), having a flat bottom and periodically heated by karst waters. Karst ravines, ravines, valleys and canyons differ from one another in the steepness of the slope and the nature of the runoff absorption (from partial to complete). Ditches are elongated corrosion-gravity depressions with steep sides, usually oriented parallel to the crest of the slope. With selective dissolution, positive forms occasionally appear - remnants (towers, cones, etc.).

Underground karst forms include negative corrosion, corrosion-erosion or corrosion-gravity forms, having a width or height at the entrance less than the length or depth (caves, wells, mines). Caves are horizontal, inclined or complex (labyrinth) cavities in karst rocks with a cross section of more than 30 cm. Vertical cavities in karst rocks of a cone-shaped, cylindrical, slit-like or other complex shape up to 20 m deep are called wells; and with a depth of more than 20 m - mines.

Karst deposits - sediments of different genesis, composition and size - are formed in surface and underground karst forms (residual clay; landslide accumulation; water mechanical deposits; carbonate flour, breccia, calcareous tuff, stalactites, stalagmites, stalagnates, bark, cave pearls; bone material , ice, etc.).

One of the main conditions for the development of karst is the presence of carbonate, sulfate or salt rocks in the section of the earth's crust. According to their lithology, four subgroups are distinguished: I - strata of the same type of karst rocks; II - strata of interbedding of different types of karst rocks; III - strata of interbedding of karst and non-karst rocks; IV - interlayers of karst rocks among non-karst ones; seven lithological types: carbonate, sulfate, hydrochloric, carbonate-sulfate, terrigenous-carbonate, terrigenous-sulfate, carbonate-terrigenous; nine lithological types: limestone, dolomite, chalk, gypsum, rock salt, limestone-gypsum, terrigenous-limestone, terrigenous-gypsum, limestone-terrigenous.

According to the nature of the overlying deposits, karst types are distinguished: open (karsting rocks come to the surface or are covered with sedimentary unconsolidated deposits up to 2 m thick), covered (karsting rocks are covered with sedimentary unconsolidated deposits of various genesis with a thickness of more than 2 m), overlapped (karsting rocks are covered with sedimentary cemented deposits, igneous or metamorphic rocks of different thicknesses), overlapped-covered (karsting rocks are overlain by sedimentary cemented, igneous or metamorphic rocks and sedimentary non-cemented deposits of different thicknesses).

Separately, manifestations of hydrothermokarst are distinguished - the processes of dissolution of rocks, the formation and filling of karst forms and fluids. Hydrothermokarst, mainly in carbonate rocks, is associated with the formation of many deposits - lead, zinc, antimony, mercury, uranium, gold, fluorite, barite, celestite, Icelandic spar, bauxite, etc.
More than 60% of the territory of Russia is subject to the development of karst processes in rocks from the Archean-Proterozoic to the Neogene age. The most developed are terrigenous-carbonate (40%), carbonate-terrigenous (24%) and carbonate (14%) lithological types of karst.

The largest area (40.6%) is occupied by territories of a simple structure, where in the section there are overlapping karst rocks of one or two systems, 24% of the territory has a complex structure (3–5 systems); 2% - a very complex structure (more than five systems).
Karst rocks are more developed in the European part of Russia (72%), less - in the Asian part (64%). They are present in 70% of the permafrost area and in 33% of the area covered by Quaternary glaciation.

Caves. One of the most striking manifestations of karst is the caves. They are horizontal and inclined. The caves consist of galleries, halls (grottoes), meanders (winding galleries), narrow passages and manholes, organ pipes (going up from the gallery of usually blind wells), blockages (sections of the gallery with a collapsed vault). Large caves often form labyrinths: flat (without floors or laid in one layer) or three-dimensional (going to great depths). In flooded caves, there are lakes, streams, cave rivers with waterfalls and siphons (places where the river goes under the arch of the cavity). There are caves completely filled with water.

In the middle of the twentieth century. in Russia, about 350 small karst caves were known, the longest of which were considered in limestone - Vorontsovskaya (Western Caucasus, more than 5 km), and in gypsum - Kungurskaya (Urals, 4.5 km). There was no information about karst mines in Russia. As a result of active speleological research, more than 4 thousand natural cavities of various sizes and origins have been discovered to date, of which 141 belong to large caves more than a kilometer long and more than 100 m deep. ), in gypsum - Kulogorskaya-Troya (16.25 km, Arkhangelsk region), in conglomerates - Bolshaya Oreshnaya (47.0 km, Krasnoyarsk Territory). Most of the large caves are in the Greater Caucasus (35), in the Pinego-Kuloi (22) and South Ural regions (19).

The use of caves in the country is quite diverse. For industrial purposes, they are used to organize water supply; in medical - for treatment (for example, bronchial asthma in the underground workings of a potash mine in the Perm Territory); in sports - for various sporting events; in scientific - for geological, biological, archaeological and other research; in tourism as excursion objects (Kungurskaya, Kapova, Vorontsovskaya, Big Azishskaya caves, Sablinsky catacombs).

The Kungur Ice Cave is one of the largest caves in Russia. Its length is 5.7 km. The cave is located on the outskirts of the city of Kungur (Perm Territory) on the right bank of the Sylva River at the base of the slope of Ice Mountain. The entrance to the cave is located in a rock outcrop of Lower Permian gypsum, anhydrite and dolomite. The cave is a labyrinth formed in the slope part of the Sylva river valley. The average thickness of the roof is 65.0 m. Based on the theodolite survey conducted by E. P. Dorofeev, a plan of the cave was drawn up, which includes 48 grottoes (the largest are the Geographers grotto, about 50 thousand m3, the Velikan grotto, about 45 thousand m3). The amplitude of the cave is 32 m, the area is 65.0 thousand m2; volume - 206 thousand m3. There are 70 lakes in the cave with a total area of ​​7.4 thousand m2 (the largest underground lake - Friendship of Peoples - with an area of ​​1,460 m2). In different seasons of the year, the number and size of lakes change. Kungur cave is famous for its ice formations. At the entrance to it, mainly congelation ice is developed, which occurs when water freezes (sinter, lacustrine, segregation, ice-cement and vein). ice is formed as a result of air exchange between and underground cavities or their individual sections. These are crystals (leaf-shaped, tray, pyramidal, rectangular, needle-shaped) and complex shapes (ensembles). Special observations have shown that the intensity of sublimation is 0.2 mm/day. (in the water layer). These ices have low mineralization and are sensitive to pollution.

Kapova cave (Shulgan-Tash) is located in the Republic of Bashkortostan and is part of the Shulgan-Tash nature reserve. This is one of the largest multi-storey caves in the Urals, 2,640 m long, an archaeological monument of world importance with Paleolithic paintings and ancient people's sites. It was formed in a karst massif on the right bank of the Belaya. The massif is composed of limestones of the Visean stage of the Lower Carboniferous. The entrance to the cave looks like an arch 48x18 m in size. The cave is a system of galleries, corridors and halls with a north-north-west and north-east strike, located on three levels. The most significant halls (Chaos, Drawings, Diamond, Crystal) are formed on the middle and upper tiers. At the bottom, the Shulgan River flows (average water flow is 50 l / s), which disappears from the surface 2.5 km north of the cave. In the siphon part of the river, at the entrance to the cave, the depth reaches 30 m. The oldest is the middle floor of the cave, where the modern entrance to it is located. The cave is decorated with calcite sinter formations, in winter - with ice stalactites and stalagmites.

In 1959, the zoologist A. V. Ryumin discovered Paleolithic drawings of an ancient man in the cave, which brought her world fame. To date, more than 50 different types of colorful images of animals (mammoth, rhinoceros, bison), an anthropomorphic creature, paint spots and various geometric signs in the form of trapezoids, rectangles and triangles, made in ocher of various tones, have been found in the cave. The sizes of the drawings are from 6 cm to 1.06 m. They are placed in four halls: in the Dome, Signs and Chaos on the middle tier and in the Drawings Hall on the upper tier. The age of the drawings is at least 13–14 thousand years. Points, scrapers, notched tools, blades with a blunt edge, and some other tools made of local cave limestone and calcite, as well as flint and green-brown jasper, were found in the cultural layer on the middle tier of the cave. Many legends, legends, beliefs and fairy tales are associated with the cave.

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Karst caves- these are underground cavities formed even thicker than the earth's crust, in areas where readily soluble carbonate and halogen rocks are distributed, being subjected to leaching and mechanical stress, these rocks are gradually destroyed, which leads to the formation of various karst forms. Among them, the most interesting are underground karst forms - caves, mines and wells, sometimes characterized by a very complex structure.

One of the main conditions formation of karst caves is the presence of karst rocks, characterized by significant lithological diversity. Among them are carbonate rocks (limestones, dolomites, writing chalk, marbles), sulfate (gypsum, anhydrite) and halide (rock, potassium salts). Karst rocks are very widespread.

In many places, they are covered by a thin cover of sandy-argillaceous deposits or directly come to the surface, which favors the active development of karst processes and the formation of various karst forms. The intensity of karst formation is also significantly affected by the thickness of the rocks, their chemical composition and occurrence features.

Water is the builder of karst caves

As already mentioned, the builder of karst caves is water. However, in order for water to dissolve rocks, they must be permeable, i.e., fractured. Rock fracturing is one of the main conditions for the development of karst. If the carbonate or sulphate massif is monolithic and consists of solid rock varieties devoid of fracturing, then it is not affected by karst processes.

However, this phenomenon is rare, since limestones, dolomites and gypsums are fissured in nature. Cracks that cut through limestone massifs have a different origin. Highlight cracks lithogenetic, tectonic, mechanical unloading and weathering. The most common are tectonic cracks, which usually cut through different layers of sedimentary rocks, without refracting during the transition from one layer to another and without changing their width.

Tectonic fracturing is characterized by the development of complex mutually perpendicular cracks 1–2 mm wide. Rocks are characterized by the greatest fragmentation and fracturing in zones of tectonic disturbances.

Falling on the surface of a karst massif, atmospheric precipitation penetrates deep into this massif through cracks of various origins. Circulating through underground channels, water leaches the rock, gradually expands the underground passages and sometimes forms huge grottoes. Moving water is the third prerequisite for the development of karst processes.

Without water, which dissolves and destroys rocks, there would be no karst caves. That is why the features of the hydrographic network and the peculiarity of the hydrogeological regime largely determine the degree of trickiness of the karst strata, the intensity and conditions for the development of underground cavities.

Rain and melt snow water

The main role in the formation of many karst cavities is played by infiltration and inflation rain and snowmelt waters. Such caves are corrosion-erosion origin, since the destruction of the rock occurs both due to its chemical leaching and by mechanical erosion. However, one should not think that these processes proceed simultaneously and continuously.

At different stages of the development of caves and in different parts of them, one of these processes usually dominates. The formation of some caves is entirely associated with either corrosion or erosion processes. There are also nival-corrosion caves, which owe their origin to the activity of melted snow waters in the zone of contact between the snow mass and karst rock. These include, for example, relatively shallow (up to 70 m) vertical cavities in the Crimea and the Caucasus.

Many caves arose as a result of the collapse of the roof over underground corrosion-erosion voids. Some natural cavities were formed by leaching of rocks by artesian, mineral and thermal waters ascending along cracks. Thus, karst caves can be of corrosion, corrosion-erosion, erosion, nival-corrosion, corrosion-gravity (failure), hydrothermal and heterogeneous origin.

condensation water

In addition to infiltration, inflation and pressure waters, condensation waters also play a certain role in the formation of caves, which, gathering on the walls and ceiling of the caves, corrode them, creating bizarre patterns. Unlike underground streams, condensation waters affect the entire surface of the cavity, and therefore have the greatest impact on the morphology of the caves.

Particularly favorable conditions for moisture condensation are characterized by small cavities located at a considerable depth from the surface, since the amount of condensation moisture is directly dependent on the intensity of air exchange and inversely on the volume of the cavity. Observations carried out in , showed that 3201.6 m3 of water condenses during the year, and 2500 times more (i.e. 0.008004 km3) in the underground cavities of the entire main ridge. These waters are highly aggressive.

Their hardness exceeds 6 meq (300 mg/l). Thus, due to infiltration waters, the caves of the Crimean Mountains, as shown by simple calculations, increase by about 5.3% compared to the total volume. The average mineralization of condensation waters is about 300 mg/l, therefore, they carry out 2401.2 tons (8004 106l X 300 mg/l) of calcium carbonate during the year.

The total removal of calcium carbonate by karst springs in the Crimean Mountains is about 45,000 tons/year. Consequently, the role of condensation water in the formation of underground cavities is relatively small, and their impact on the rock as a denudation agent is limited mainly to the warm period.