Cave formation. Formation and development of caves. Geographical object. The meaning of caves

One summer, I found myself in a cave for the first time, and in the famous Petralona cave, 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 began, 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. Moving from hall to hall of this cave, I thought how it is that “icicles” - stalactites - hang from above. Why do they have such bizarre shapes and don’t melt? And from below, like trees, other “icicles” grow - stalagmites. What do they grow from if there are stones around? Why don't they fall? Why are they 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 can such a curiosity be useful in everyday life?

Returning home, I decided to investigate this issue. And we had to start by studying the “habitat” of these amazing cave formations - from the caves themselves. It turned out there was a lot of interesting and exciting things here too. I still had an initial idea and information after visiting the Greek cave. Our guide spoke very interestingly and in detail about the cave I was in. But how are the caves themselves born? And why do stalactites and stalagmites appear in them, and nowhere else? What are these stalactites made of?

During my research, in order to solve the problems, 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 stalactite at home.

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

Caves. Their education.

A cave is a natural cavity in the upper layer of the earth’s crust, which communicates with the surface of the earth by one or more exit openings passable to humans. 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 study for speleology.

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 ancient people stopped using caves as homes, the caves were surrounded by an aura of the unusual and strange. The Greeks believed that the caves were temples to their gods - Zeus, Pan, Dionysius and Pluto. IN ancient Rome It was believed that nymphs and witches lived in the caves. The ancient Persians and other peoples believed that the king of all earthly spirits, Mithras, lived in the caves. These days, the vast and beautiful caves attract tourists.

In nature, there are no two identical caves. Caves are formed 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. The rains poured, the rivers overflowed, and the monolithic mountains slowly collapsed, and large voids appeared inside the hills, mountains and rocks (Appendix 1).

The rock in which the caves appear is limestone. It is a soft rock and can be dissolved by a 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, for millions of years, acid rain watered the limestones. They constantly dripped onto the mountains, and cracks began to appear on them. And the rains continued to fall. The water flowed, widening the cracks. She found new cracks in the monolith. The cracks expanded into tunnels. The tunnels crossed and niches appeared. After millions of years, the caves took their shape. And the water made the caves larger and larger.

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, 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 rocky soil made of soft rocks. Caves are built not only by water, but also by wind, sea surf, and volcanic lava. Caves remain after rock salt mining. There are also ice caves, but they are short-lived.

Types of caves.

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

Tectonic caves can occur in any rock as a result of the formation of tectonic faults. As a rule, such caves are found on the sides of river valleys deeply cut into the plateau, when huge masses of rock break off from the sides, forming cracks (sherlops), which in turn usually converge like a wedge with the depth. Sometimes they form quite deep vertical caves up to 100 m deep. This type of cave is widespread in Eastern Siberia.

Sea caves arose under the influence of splashing waves on rock cliffs along the coast (Appendix 3). Sea waves containing grains of hard material (pebbles, fine sand) dissolved the cliffs. They were destroyed, undermined year after year by the surf. Some caves are located underwater. They are usually the result of the activity of groundwater, washing away soft rocks, for example, the same limestone.

Glacier caves are found in many glaciers and are formed inside glaciers by meltwater (Appendix 4). Glacial meltwater is absorbed by the glacier along large cracks or at the intersection of cracks. In this case, passages are formed along which a person can sometimes pass. Such caves have the shape of a well and reach depths of 100 meters or more. In 1993, the 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 where underground thermal waters emerge. Since the water is hot, it is capable of creating 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 and Greenland and reach significant sizes.

Volcanic or lava caves occur during volcanic eruptions (Appendix 5). The lava flow, as it cools, becomes covered with a hard crust, forming a lava tube, inside which molten rock still flows. After the eruption has actually 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 extent 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 especially marble, dissolve very poorly in 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, limestone still dissolves poorly, compared to, say, gypsum or, especially, salt. But it turns out that this has a positive effect on the formation of extended caves, since gypsum and salt caves not only form quickly, 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 caves - from +15 to +28.

It turns out that the air in the caves is sterile. It contains a thousand times fewer microbes than on the surface. It turns out that radioactive carbon isotopes penetrate into the caves along with groundwater. They cause stalactites to glow, ionize the air, and 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 Krubera-Voronya cave. A person can descend 2 kilometers into it.

Despite the fact that so much is already known about the caves, new discoveries await scientists ahead. 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 - a corridor, beyond which there are several more meters of cave beauty.

As a result of these studies, we can conclude that there are several types of caves, but the most common are karst ones. To form a cave, a sufficient amount of water sediments and a favorable shape of the relief are necessary, that is, sediments from a large area must fall into the cave, and the entrance to the cave must be located noticeably above the place where the groundwater is discharged.

Stalactites, stalagmites and stalagnates

Water is a great force. She sharpens the stone when she makes her way, she builds galleries, and then leaves them, undermines the 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 and sculptor!

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

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

Stalactites (from the Greek stalaktós - flowed drop by drop) are drip-drip formations hanging in the form of conical icicles, draperies, curving fringes 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-drip formations of columnar, conical and other shapes, rising from the bottom of caves and other underground karst cavities (Appendix 8).

Stalagnates are drip-drop formations in the form of columns that appear in caves when stalactites and stalagmites are connected (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 the mineral calcite from it. A drop of a 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 particle of calcite or other mineral it brought settles on the ceiling in a thin film. After some time, the next droplet comes to this place and again deposits calcite. As they grow, grains of calcite first turn into a thin, transparent tube that is empty 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 an ice one - a stalactite.

But the drops arrive unevenly, from one side to the other, and the stalactite is not entirely round. And then it rains on the surface, the water becomes dirty, the stalactite darkens. The rain stopped, the water was clear again, and the next layer of stalactite became a different color. If you cut it, then the cut will have the same rings as a tree, but not annual ones. There is simply more water in spring and autumn, 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 process of stalactite formation. Here it is: CaCO3 + H2O + CO2 Ca2+ + 2 HCO3

But not all the calcite settles on the ceiling and gives rise to stalactite growth. 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 connect and grow together, a calcite column is formed - a stalagnate. Both stalactites, 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 smudges appear in the form of ribs. If the drops flow down the wall of the cave, then no less amazing deposits appear on it in the form stone waterfalls, flags and other fantastic formations.

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

Where there is an imbalance in the flow of solution - for example, it drips from above, but so little that the drops immediately spread out like a film - hybrid forms arise, the stalagmite blooms as 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 plaster web, which is thinner than a human hair, crumbles into dust at the slightest vibration of air.

Billions of drops over millions of years created in the cave a whole forest of stalactites, stalagmites, a 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” of various shapes and colors. The smallest particles of salts of various minerals and metals - copper, cobalt, iron - make the stains pink, yellow, blue, red, carrot, black. So-called cave pearls are very rarely found in “baths”. It is formed in the same way as sea water, but not in a shell. Sometimes cave pearls reach three to five centimeters in diameter - almost like a ping-pong ball - but this is very rare.

In karst caves you can find a wide variety of stalactites. For example, tubular stalactites, also known as pasta. For centuries, a channel running along their entire length automatically led researchers to believe that the stalactite was fed through this channel. But it turned out that this is 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 broken ones do not continue the original tube, but grow slightly to the side, where it is more convenient for water to drip.

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

When a mineral changes, say, calcite to gypsum, the cave changes, 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 spruce trees”.

They are formed 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 “loves” to settle in depressions, and evaporate from ledges - this is elementary physics. And then it turns out that the internal cavity of the stalagmite continues to dissolve, and the outer surface continues to grow, moreover, into branchy bushes of crystals. Those same “snow-covered spruce trees” appear. When the wall becomes thinner so that the stalagmite no longer supports its own weight, then “dying” it falls inside 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 over a hundred years it increases by only four centimeters. And after 100 years, a stone icicle will appear in 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 - a stalagmite - will grow. After millions of years, the stalactite and stalagmite will unite and turn into a sparkling column. This means that a person who broke a meter-long stone icicle destroyed what nature had been creating for about two and a half thousand years!

Thus, during the research, I learned that stalactites, stalagmites and stalagnates are drip-drip formations in caves. The process of formation of stalactites and stalagmites is a complex chemical process, which consists in the fact that water dissolves rock, transports it to another place and after some time deposits it back, creating sinter formations. This process lasts hundreds, thousands of years.

Other cave mysteries

Paleontology is a science that deals with the study of fossil plants and animals. Fossils are the remains of animals that lived millions of years ago that have survived to this day. Thanks mainly to the study of fossils, we know what it was like animal world 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 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 Chalkidiki peninsula, in northern Greece, at an altitude of 250 meters above sea level at the foot of Mount Katsika, a cave entrance was discovered. It all happened completely by accident, a shepherd named Petralona was tending sheep in the area. One day, having heard the soft murmur of water, I decided to carefully examine the foot of the mountain and came across the entrance to a cave. Further research was carried out 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 an excursion.

The area of ​​the cave is 10 thousand square meters, the total length of the corridors (passages) is 1,500 meters. A 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 opening of the cave itself, the skull and skeleton of the oldest European, Neanderthal man, called the Archanthropus, were discovered inside. The results of the first study of the skull were presented at the International Congress of Anthropologists in Moscow in 1964 and produced great impression for specialists.

In addition, fossilized bones, stone tools, and the remains of animals - bears, hyenas, turtles, rhinoceroses, 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 human use of fire.

Until recently, it was believed that the age of humanity is 3.5-4 million years, and its homeland is Africa. However, finds from the Petralone cave and their dating give the right to assume that the cradle of humanity 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 secrets in the caves. As I found out during my research, the animal world of the dungeons is unusual and interesting. Even primitive man knew and drew on the walls the animals that lived in caves - a cave lion, a hyena, a cave bear. By the way, rock paintings also contain a lot of information interesting for scientists (Appendix 25).

Ancient animals became extinct long ago, people left the caves, but the caves themselves were not empty. Serious biological research 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 “cave-dwelling” - crustaceans, fish, woodlice, centipedes, spiders, pseudoscorpions 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 caves, they do not need vision and therefore have no eyes. Blind beetles, fish, amphibians, crayfish and even blind and wingless flies are found in the caves. The air in caves is saturated with moisture, and therefore troglobionts can live both in water and on land.

According to scientists, animals and insects went into caves due to climate change on Earth, namely during cold weather. 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 dark lovers spend only part of their lives underground. For example, butterflies only spend the winter in caves. And some species of grasshoppers, which are nocturnal, stay there all day. This included the cave bear, because the cave was only a resting place for him. The hyena and lion spent even less time in the caves. Unlike the cave bear, they never went far into the cave, but stayed near the entrance.

Treasures of the caves are another mystery and mystery of the caves. For many millennia, legends and tales speak of treasures hidden in caves. The bones of lost treasure hunters who never managed to find treasures have been found underground more than once. One of the caves in the Czech Tatras is called the Cave of Treasure Seekers. And there are so many legends about pirate treasures hidden, including in caves. But every legend has some truth.

CONCLUSION

The object of my research was caves and their mysteries, the main of which are stalactites, stalagmites and stalagnates, the mechanism of their formation and the possibility of creating them in everyday conditions, that is, at home. At the beginning of my 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 during the 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 topography 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 extraordinary and beautiful phenomenon as a stalactite or stalagmite. There is only one thing left to do - admire and cherish.

Based on the results of my research, I can draw the main conclusion - there are such natural phenomena, which a person should study, cherish, 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 speed up 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, to see and appreciate the beauty that nature can create. And also, suddenly the climate on the Planet will change dramatically again and people will have to return to the caves again. With this knowledge, it will be easier for me to get comfortable there myself and help others.

Caves are cavities formed in the upper part of the earth's crust as a result of natural processes. This is how scientific language describes these mysterious objects prosaically. However, true connoisseurs of caves will always have living words for them.

So, for example, Alfred Begley, a Swiss cave explorer, said about them: “Under the earth’s surface in absolute darkness there is such a huge world that we can talk about a new continent.”

Geographical object. The meaning of caves

The importance of caves for humans can hardly be overestimated. After all, caves were the first homes for primitive people, so revealing the secrets kept by caves helps add missing puzzles to the picture of human history and evolution.

The great educational value of caves is evidenced by the increased interest in speleology in recent decades, both on the part of researchers and on the part of tourists and adventure lovers. Around the world, the number of caves prepared for tourist visits is growing.

Karst cave cavities are of great importance for agriculture, since their presence leads to the withdrawal of groundwater to greater depth, drying out the upper layers of the soil, which must be taken into account when planning agricultural work. And some caves with a microclimate characterized by particularly low temperatures are used as large “refrigerators” for storing food and various materials.

Caves are of great importance for the extraction and research of various minerals and some iron ores.

Characteristics of caves

Caves are protected from the outside world, have a constant internal climate and evolve extremely slowly. These characteristics make them invaluable for archaeology: the caves have preserved for us the remains of ancient people, the bones of extinct animals and plant pollen.

The speleofauna is not particularly diverse, and yet there are animals and plants that live mainly in caves or only in them. These are bats that perfectly navigate even the longest and most confusing underground passages, some insects, shrimp and other crustaceans, spiders, fish and salamanders. Cave dwellers, adapted to complete darkness, are often completely blind and lack pigment.

Cave deposits are divided into mechanical and chemogenic. Mechanical deposits are clay, blocky rubble, sand, pebbles; chemogenic - stalactites and stalagmites decorating ancient cave galleries.

Types of caves

Exist artificial(educated by man) and natural(formed by natural processes) caves. Natural caves are divided according to their origin (leading process) into the following five types.

Karst. The largest group. They are the most beautiful, deep and extended. The process of their formation is a consequence of the dissolution of various rocks in water (gypsum, limestone, chalk, salt, marble, etc.). It is in karst caves that stalactites, stalagmites, as well as helicates and amazing cave onyx are formed.

Erosive. The formation process is similar to karst caves, however, erosion caves are formed as a result of mechanical erosion, i.e. washed out with water containing solid particles (sand, stone fragments, etc.). Often formed by coastline.

Tectonic. They are formed at the sites of tectonic faults. They are most common on the sides of river valleys, wedged deep into the plateau.

Volcanic. They are formed as follows: during a volcanic eruption, the lava flow cools and becomes covered with a crust, forming a lava tube. Inside the pipe, the lava continues to flow for some time, resulting in the formation of a cavity. Also classified as volcanic are caves formed by volcanic vents.

Glacial. Formed in the body of glaciers. Among glacial caves, there are caves formed by melt water, caves formed in glaciers at the outlet of subglacial and intraglacial waters, as well as caves formed in glaciers at the outlet of subglacial thermal springs.

The largest caves

(Son Doong Cave)

The largest cave in the world is the cave opened in 2009 Shondong V Central Vietnam(Quang Binh province). More famous, but smaller Mammoth Cave , located in Kentucky, USA. It is a system of karst caves formed in a limestone layer.

In Russia the longest is Botovskaya, whose length reaches 60 km. Located in Romania Movile cave- one of three caves in the world formed as a result of exposure of rock to sulfuric acid. The cave is unique in that it is a closed ecosystem, isolated from the Earth's ecosystem.

Deepest cave

(Krubera Cave)

The deepest cave in the world - Krubera cave or Crow- located in Abkhazia (Gagra ridge). The cave branches into two branches: the depth of one is 2,196 m, the depth of the other is 1,300 m. It was discovered in 1960.

Longest cave

The longest in the world is the one already mentioned above. Mammoth cave system(Kentucky, USA). Its length is 627,644 m. Mammoth Cave lies in the foothills of the western Appalachians and in the explored part there are 20 large halls, the same number of deep shafts and about 225 underground passages.

Moscow State Institute of Steel and Alloys

Vyksa Branch

(University of Technology)

Abstract on the subject

crystal physics

On the topic: “Formation of caves and karsts”

Student: Pichugin A.A..

Groups:MO-07 (MFM)

Teacher: 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. Glacier caves

5. Lava Cave

V. Caves in the Baikal region

VI. Cave Kyzylyarovskaya named after. 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 relief forms that arise in areas composed of relatively rocks that are easily soluble in water (gypsum, limestone, marble, dolomite and rock salt).

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

Based on the depth of the groundwater level, karst is distinguished between deep and shallow. There are also “bare” or Mediterranean karst, in which karst relief forms are devoid of soil and plant cover (for example, Mountain Crimea), and “covered” or Central European karst, on the surface of which the weathering crust is preserved and soil and plant cover are developed.

Karst is characterized by a complex of surface (craters, quarries, trenches, 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, shafts or failures. Karst sinkholes or other elements of surface karst through which surface water flows into the karst system are called ponors.

KARST, limestone plateau - a complex of irregularities, convex rock outcrops, depressions, caves, disappeared streams and underground drains. Occurs in water-soluble and weathered rocks. The process is typical for limestone, as well as in places where rocks are washed away. Many rivers are underground, and 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 Crimean mountains and in the Urals.

Karst can be observed in the Western Alps, in the Appalachians (USA) and in southern China because layers of limestone rocks, first consisting of a layer of calcite (calcium carbonate), up to 200 m thick, were partially eroded by water. Carbon dioxide from the atmosphere 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 process can turn into gorges, and finally, the remains of limestone that have not been eroded, characteristic of a karst landscape, remain.

Cave- a natural cavity in the upper layer of the earth's crust, communicating with the surface of the earth by one or more exit openings passable for humans. 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 study for speleology.

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

HYPOTHESIS ABOUT THE ORIGIN OF KARST AREAS

Namely, there is a hypothesis that:

In ancient times 300-400 million years ago in sea ​​water There was a process of growth and death of living organisms that intensively used calcium to build their shells. The water was a saturated solution of calcium carbonate. The dead shells sank to the bottom and accumulated along with sediments that precipitated out of solution as a result of climate change;

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

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

At the moment of movement of 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 undisturbed (as near Moscow); 2) the bottom bulged out to form mountains, while the integrity of the limestone layers was violated, and 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 remains of ancient shells and other former living organisms in the limestone layer. Be that as it may, it is clear that caves and the rocks where they form are closely related to ancient life on Earth.

CONDITIONS FOR CAVE FORMATION

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

1. 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 water.

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

At the border of karst and non-karst rock,

Tectonic (usually transverse),

So-called side thrust cracks.

Scheme of the formation of vertical elements of caves (wells, shafts, abysses): Leaching.

Wells are formed at the intersection of tectonic cracks - at the mechanically weakest point of the massif. Water from atmospheric precipitation is absorbed there. And slowly dissolves the limestone; Over millions of years, water expands the 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 passages:

Water, having penetrated through the layer (layer) of karst rock, reaches the bedding crack and begins to spread along it along the plane of “dip” of the layers. The leaching process occurs and a subhorizontal passage 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 boundary of karstic and non-karstic rocks and then spread only along this boundary. Usually an underground river already flows here and there are siphons. This is a zone of horizontal circulation of groundwater.

Formation of halls.

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 mountain building again (earthquakes, landslides).

Sometimes additional mechanisms are activated:

Mechanical removal of rock fragments by water flows,

The effect of pressure thermal waters (New Athos Cave).

A cave is a cavity in the upper part of the earth's crust, connected to the surface by one or more entrance holes. Another definition: a cave is a natural underground cavity accessible to human penetration, having parts not illuminated by sunlight and a length (depth) greater than the other two dimensions. 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 study for speleology. Speleotourists make a significant contribution to the study of caves.

Caves according to their origin can be divided into five groups: tectonic, erosion, glacial, volcanic and, finally, the largest group - karst. The caves in the entrance area, 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 are like this. It is karst caves that have the greatest extent and depth. Karst caves are formed due to 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 especially marble, dissolves very poorly in pure distilled water. Solubility increases several times if dissolved carbon dioxide is present in the water (and it is always present in natural water), but still limestone dissolves poorly compared to, say, gypsum or, especially, salt. But it turns out that this has a positive effect on the formation of extended caves, since gypsum and salt caves not only form quickly, but also quickly collapse.

Tectonic cracks and faults play a huge role in the formation of caves. From the maps of the studied caves one can 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 sediments and a successful relief shape are necessary: ​​sediments from a large area should fall into the cave, the entrance to the cave should be located noticeably above the place where the groundwater is discharged, etc.

Many karst caves are relict systems: the water flow that formed the cave left it due to changes in the topography either to deeper levels (due to a decrease in the local basis of erosion - the bottom of neighboring river valleys), or stopped flowing into the cave due to changes in the surface catchment, after which the cave goes through various phases of aging. Very often, the caves studied are small fragments of an ancient cave system, exposed by the destruction of the host mountain ranges.

The evolution of karst processes and their chemistry are such that often water, having dissolved the 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 thick or more (cave marble onyx) or special for each cave of ensembles of mineral aggregates of caves, forming stalactites, stalagmites, helictites, draperies and other specific karst mineral forms - sinter formations.

Recently, more and more caves have been opening in rocks that were traditionally considered non-karst. For example, in the sandstones and quartzites of the tepui table mountains of South America, the Abismo Gai Collet caves, with a depth of −671 m (2006), and Cueva Ojos de Cristal, with a length of 16 km (2009), were discovered. Apparently, these caves are also of karst origin. In hot tropical climates, under certain conditions, quartzite can be dissolved by water.

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

Tectonic caves

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

Erosion caves

Caves formed in insoluble rocks due to mechanical erosion, that is, worked through by water containing grains of solid material. Often such caves are formed on the seashore under the influence of the surf, but they are small. However, the formation of caves is also possible, excavated along primary tectonic cracks by streams going underground. Quite large (hundreds of meters long) erosion caves formed in sandstones and even granites are known. Examples of large erosion caves include 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).

Glacier 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, depth - up to 100 m or more. In 1993, a giant glacial well “Isortog” with a depth of 173 m was discovered and explored in Greenland; the influx 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 of release of intraglacial and subglacial waters 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 are caves formed in glaciers at the outlet of underground thermal waters located under the glacier. Hot water can create voluminous galleries, but such caves do not lie in the glacier itself, but underneath it, since the ice melts from below. Thermal glacial caves are found in Iceland and Greenland and reach significant sizes.

Volcanic caves

These caves appear during volcanic eruptions. The lava flow, as it cools, becomes covered with a hard crust, forming a lava tube, inside which molten rock still flows. After the eruption has actually 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 in length and 1100 m in depth (Kazumura Cave, Hawaiian Islands).

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

Caves by type of host rock

The longest cave in the world, Mammoth Cave (USA), is a karst cave built in limestone. It has a total length of passages of more than 600 km. The longest cave in Russia is the Botovskaya cave, over 60 km long, laid in a relatively thin layer of limestone, sandwiched between sandstones, located in the Irkutsk region, 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 Optimisticheskaya, 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 containing the cave are covered with limestone on top, due to which the vaults do not collapse. There are known caves in rock salt, in glaciers, in solidified lava, etc.

Caves by size

The deepest caves on the planet are also karst: Krubera-Voronya (up to −2196 m), Snezhnaya (−1753 m) in Abkhazia. In Russia, the deepest cave is Gorlo Barloga (−900 m) in Karachay-Cherkessia. All these records are constantly changing, but only one thing remains constant: karst caves are in the lead.

The deepest caves in the world

The depth of a cave is the difference in height between the entrance (the highest of the entrances, if there are several of them) and the lowest point of the cave. If there are passages in the cave located above the entrance, use the concept of amplitude - the difference in levels between the lowest and highest point caves. 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 that, any cave will be crushed by the weight of the overlying rocks. For karst caves, the maximum depth is determined by the karst base (the lower limit of karst processes, coinciding with the base of the limestone strata), which can be lower than the erosion base due to the presence of siphon channels. Most deep cave, is currently the Krubera-Voronya cave with a depth of 2196 m, this is the first and only cave that has crossed the 2 km mark. The first cave to be explored with a depth of more than 1000 meters was the French Berger Chasm, which was considered the deepest in the world from its discovery in 1953 until 1963.

		Depth, m		Location
1	Krubera-Voronya
2
3
4	Lamprechtsofen
5	Mirolda
6	Jean-Bernard
7	Torca del Cerro
8	Pantyukhinskaya
9	Sima de la Corniza
10				Slovenia

The longest caves in the world

			Depth, m	Location
1	Mamontova
2
3	Ox-Bel-Ha
4	Optimistic
5
6
7	Sak-Actun
8				Switzerland
9	Fisher Ridge
10	Gua-Air-Jernich			Malaysia

Contents of the caves

Speleofauna

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

In addition to bats, some caves in warm climates are home to several species of insects, spiders (Neoleptoneta myopica), shrimp (Palaemonias alabamae) and other crustaceans, salamanders and fish (Amblyopsidae). Cave species adapt to complete darkness, and many of them lose their organs of vision and pigmentation. These species are often very rare, many of them endemic.

Archaeological finds

Prehistoric people used caves all over the world as homes. Even more often, animals settled in caves. Many animals died in trap caves starting from vertical wells. The extremely slow evolution of caves, their constant climate, and protection from the outside world have been preserved to us great amount archaeological finds. This is pollen from fossil plants, bones of long-extinct animals (cave bear, cave hyena, mammoth, woolly rhinoceros), rock paintings of ancient people (Kapova caves on Southern Urals, Divya in the Northern Urals, Tuzuksu in Kuznetsk Alatau, Niah-Caves in Malaysia), tools of their labor (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 served as modern cinemas.

Water in caves

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

Air in 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 overwhelming 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 time of year and weather conditions. In large cavities, the air movement is so intense that it turns into wind. For this reason, air draft is one of the important signs when searching for new caves.

Cave deposits

There are mechanical (clay, sand, pebbles, blocks) 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 rubble, often of very large volumes, formed as a result of the collapse of the arch of passages, which is formed by dissolution of the water flow. Rubbles are difficult to pass and dangerous, since the balance of a blocky rubble is often unstable. Clay deposits are widely represented in galleries that were abandoned by an active watercourse that carried out mechanically insoluble rock particles. The soluble component of the cave's limestone is calcium carbonate, which often makes up only about 50% of the rock. The remaining minerals, as a rule, are insoluble, and if the water dissolving the rock is presented in the form of a drop, an infiltrate, with low water flow, unable to provide mechanical transport of particles, the accumulation of clay deposits begins. Very often ancient passages are completely blocked with clay.

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

Excursion caves

Some caves are equipped for visiting by excursion groups (so-called showcaves). To do this, in the part of the cave that is most spacious and rich in sinter formations, pedestrian paths, ladders, bridges are laid, and 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 Mramornaya in Crimea, Kungurskaya in the Urals, and Novoafonskaya in Abkhazia.

Caves in the Solar System

In addition to the Earth, caves have been discovered 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 big city there is a system of technical dungeons: basements of above-ground buildings, metro, life support systems (plumbing, heating, sewerage, electrical and telephone cables, fiber optic network), bomb shelters, bunkers in case of war, etc.

The cave is like the dwelling of holy ascetics

Many holy ascetics built their homes in the caves. Later, monasteries and Lavras were founded on these places:

• Kiev-Pechersk Lavra
• Pskov-Pechersky Monastery
• Holy Dormition Cave Monastery (Crimea)
• Kholkovsky Monastery
• Chelter-Koba
• Basarbovsky Monastery
• Cave churches in Ivanovo

Holy ascetics who lived in caves:

• “And Lot went out from Zoar and lived in the mountain, and his two daughters with him, for he was afraid to live in Zoar. And he lived in a cave, and with him his two daughters" (Genesis 19.30)
• “And he the Prophet Elijah entered a cave there and spent the night in it” (3rd Book of Kings 19.9)
• Hilarion of Kyiv
• Anthony Pechersky
• Varlaam Pechersky

Caves-houses

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

• Cappadocia
• Anasazi
• Guadiz
• Sassy Di Matera

Medicinal caves

Many medical institutions have rooms called “salt caves”. The walls are lined with potassium salt bricks, and patients spend some time in them, listening to music and receiving a healing effect.

Entertaining caves

There are well-known caves of horror as part of amusement parks, cafes and bars decorated to look like caves.

Caves in mythology, mysticism and religion.

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

Caves in art, literature and film

Caves appear in many fantasy works (both fantasy and science fiction). Caves (more precisely, bunkers) in science fiction mainly serve as shelters after a global catastrophe that has made life on the surface impossible. And also caves in fantasy are inhabited by: gnomes, kobolds, goblins, dragons, and in Russian folk tales the “Mistress of the Copper Mountain”, the Serpent Gorynych, lives there. In northern mythology, Sirtya live in caves. One of the most famous literary heroes who ended up in the caves was: Tom Sawyer, along with Becky Thatcher, Bilbo Baggins.

Underground cavities

In addition to caves that have access to the surface and are accessible to direct human exploration, 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 during drilling. On Black Sea coast In Gagra, drilling discovered underground voids at a depth of up to 2300 meters.

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

Caves are empty spaces in rock formations underground or under water, as well as above ground. Caves can be through-holes with several openings or with one. They are divided into horizontal, vertical, as well as inclined and single-level or multi-level. The sizes of the caves also vary. 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 made 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 creating these caves is groundwater, saturated with carbon dioxide, which seeps through cracks along the limestone layers. This process, in their opinion, takes millions of years. But recently another factor has become known that washes out caves much faster - sulfuric acid.

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

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