The world ocean covers about 70 percent of the Earth's surface, but it is only 5% studied by people. It turns out that humanity does not even imagine what secrets the deep blue waters hide. And this review contains a “ten” of incredible ocean finds that open up new facets of the past for people. present, and sometimes even allow you to look into the future.

1. Movement of tectonic plates

coast of Iceland
IN last years The North American and Eurasian tectonic plates are moving further apart as the North American plate moves westward. This impressive phenomenon can be seen both on land and deep underwater by diving between these two plates near Iceland. This has already been done by a number of underwater photographers and scuba divers.

Diver and marine biologist Alexander Gorchak, who explored the area, described his experience as something incredible. However, he notes that untrained visitors to the site can easily become disorientated and dizzy due to the colossal "walls" of the slabs and the crystal clear water. Now the plates diverge at a rate of about 2.5 cm per year.

2. City of Pavlopetri

south coast of Greece
Discovered in 1967 by Dr. Nick Flemming, this seaport Neolithic era can be found underwater at south coast Greece. Ancient pottery was discovered at this site, so archaeologists have suggested that the city of Pavlopetri traded both on land and at sea. According to Flemming, Pavlopetri is thousands of years older than most ancient underwater ruins that have already been discovered. The estimated area of ​​the city is about 100,000 square meters.

The remote location saved the ruins from looting and final destruction. Neolithic pottery is one of the most notable finds in this underwater city. It was thanks to her that the researchers realized how ancient these ruins are. Pavlopetri was originally thought to have been built during the Bronze Age. But after further research, the city turned out to be more than 1,000 years older than previously thought.

3. Underwater river

Black Sea
At the bottom of the Black Sea there is a whole ecosystem with a flowing river, rapids and waterfalls. It sounds crazy - a river flowing along the bottom of the sea ... In fact, this is because the water in the river is much more salty and, therefore, denser than the surrounding water in the Black Sea. The high salinity of this water allows it to flow rapidly across the sea, thus creating a river. As if that weren't unusual enough, the river's large volume (35 meters deep and 1 kilometer wide) is believed to make it the sixth deepest river in the world.

Finding this wonderful little ecosystem in the sea could be critical to researchers' understanding of Earth's oceans in general. A discovery like this could potentially help scientists better understand life underwater and the various conditions that allow such phenomena to occur on our planet.

4. Pearl Canyon

Bering Sea
Those who think that the underwater river is impressive will definitely like this underwater canyon. It is so huge that it can only be seen from space. Located in the Bering Sea, Zhemchug is also the deepest underwater canyon. Given its volume of 5800 cubic kilometers and a depth of 2.6 kilometers, the entire Grand Canyon could fit in the Pearl. Submarines can safely travel through this canyon.

5. Bimini Road

coast Bahamas
One of the most popular tourist attractions in the Bahamas is Bimini Road - underwater road opened in the 1930s. The origin of this formation at the bottom is unknown, although many believe that this is the path leading to the lost Atlantis. Located at a depth of only 6 meters, Bimini Road is accessible to anyone who wants to dive and see the mysterious formation with their own eyes.

6. British Atlantis

North Sea
While the real Atlantis has yet to be found, a similar discovery has been made deep in the North Sea. "Doggerland" is the name of a huge landmass that sank into the ocean at least 8,500 years ago. Researchers believe that this piece of land previously stretched from Scotland to Denmark and was once inhabited by mammoths. After this land was settled by the Mesolithic people, it eventually sank to the bottom of the sea.

Those who discovered Doggerland called it "the real heart of Europe" because of its large size and the hypothetical huge hunter-gatherer community (numbering in the tens of thousands) that lived here. Doggerland is particularly impressive because it has taught scientists that the islands that are now Britain were once connected to the rest of Europe. Although this is not the real Atlantis, this underwater world is just as interesting.

7. Ruins of Atlit Yam

Mediterranean Sea
Ancient cities found deep in the sea are always intriguing, no matter how many have been discovered. The ruins of Atlit-Yam are located at a depth of 8-12 meters in the Mediterranean Sea off the coast of Israel. Discovered in 1984, the city is believed to be from the Neolithic era and is one of the largest underwater settlements ever found. During exploration in Atlit-Yam, the remains of houses, wells, people and animals, as well as objects, artifacts and mysterious structures dating back thousands of years, were found.

One of its most impressive structures is said to be a ritual site made up of huge stones arranged in a circle around what used to be a spring. Sixty-five burial sites of human remains have been found around and in the city, some of which have provided scientists with evidence of the earliest known cases of tuberculosis. Bones from wild and domesticated animals have also been found, suggesting that those who inhabited Atlit Yam hunted and raised animals for food.

8. Black smokers

coast of Norway/Greenland
Unusual smoke-like formations sometimes occur underwater when seawater meets magma. These hydrothermal vents are a type of hot springs that spurt out jets of water and liquids that reach temperatures of 370 degrees Celsius or more. They are often called "black smokers" because of the color of their "smoke", which is a suspension of sulfur compounds with iron, copper and zinc.

Similar holes have been found in various places in the world's oceans, but the northernmost group of "smokers" was discovered in the Arctic Circle between Norway and Greenland in 2008. In this place, there are five black smokers that look like underwater towers, from the tops of which black "smoke" comes out. One of them is almost four stories high.

9 Ghost Fleet

Chui lagoon
Shipwrecks are one of the most interesting things to find in the ocean. They tell the story of other times, and often thanks to them people will know what happened hundreds of years ago. Chuuk Lagoon is located on the Caroline Islands in pacific ocean, north of New Guinea and east of the Philippines.

The wreckage of countless Japanese ships and aircraft that were destroyed in World War II was found here. Jacques Cousteau made a film about the Phantom Fleet in 1969. It is claimed that the remains of the bodies still remain among the ships and aircraft, and the site itself is partially visible above the surface of the water.

10. Great Blue Hole

Belize coast
Big blue hole in Belize every year attracts curious divers and thrill seekers. Off the coast of Belize, this natural sinkhole is the largest underwater sinkhole in the world. The hole was first made into a film in 1971 by Jacques Cousteau, and the place has since become a tourist attraction.

The Great Blue Hole was formed from a limestone cave during the last ice age hundreds of thousands of years ago. Its dimensions are really impressive - this "hole" at the bottom of the sea is 300 meters across and its depth is 125 meters.

Of great interest today are and. Sometimes these finds are estimated at millions of dollars.

On the ocean floor, researchers have identified many unusual structural forms. Of these, the most studied are underwater valleys and canyons, which usually begin on the shelf and are often traced not only on the slope, but also within the ocean floor.

Canyons are an extremely common landform on the ocean floor. If you make an underwater trip along the edge of the continental shelf of any continent, then it is easy to make sure that it is literally pitted with transverse underwater ravines that cross the edge and cut deeply into the continental slope.

The dimensions of many valleys and canyons are impressive. The width of large canyons is measured in tens, and the length - many hundreds of kilometers.

A typical example of such a structure is the Congo Canyon, which is an underwater continuation of a flooded mouth - the estuary of the great African river. Already at the mouth of the estuary, the depth reaches 450 m; a deeply incised canyon crosses a shelf strip about 90 km wide and the entire slope about 120 km long (Fig. 14). As can be seen from the profile, the incision of the canyon reaches its maximum depth in the region of the edge of the continental shelf, where the height of the canyon walls reaches 1 km!

There are several hypotheses about the origin of canyons.

First of all, it is natural to assume that within the shelf the canyon is an underwater continuation of the channel, flooded as a result of the secular - eustatic rise in the level of the World Ocean. It is much more difficult to explain the continuation of the canyon on the continental slope, since it is unlikely that the level fluctuations were measured in kilometers.

It is also unlikely that a later subsidence of the continental slope occurred after the formation of a canyon on its surface. And finally, one more circumstance. If, nevertheless, we assume that submarine canyons are flooded river valleys, then their subsequent smoothing in the underwater state will be natural as a result of the accumulation of sediments brought by rivers from collapsing banks. It has been calculated, for example, that the total mass of rock fragments carried by the river. Congo into the ocean, reaches 86 million tons per year. Compared to the volume of an underwater canyon, this is a modest amount, but it is still sufficient to completely fill the canyon within just a few thousand years. At the same time, the results of a survey of the canyon walls indicate the absence of modern sediments on them and even ongoing erosion.

Thus, it is more likely to assume that submarine canyons are formed not on land, but already on the ocean floor, at least within the continental slope and deeper.

Modern researchers associate the formation of submarine canyons with turbidity flows periodically rolling down the slope from the shelf. These flows carry huge masses of loose sediments, both river and other nature, accumulating on the shelf. Such turbidity suspension flows have a significant destructive force, leading to a deepening of the canyon and erosion of its walls. Even breaks in strong transoceanic communication cables, sometimes crossing submarine canyons, are associated with the activity of turbidity flows.

The result of the activity of turbidity flows are extensive accumulations of relatively shallow sediments deposited on the shelf and then rolling down the slope, like an avalanche. Such accumulations of poorly sorted sediments transported to the foot of the continental slope are called turbidites. At opening mouths of canyons, turbidites often form alluvial fans. Thus, the top of the fan of the Congo Canyon is located at a depth of about 3.0-3.1 km. Here, already within the alluvial fan, the canyon sharply "shallows", is divided into several branches; at the same time, some of the branches continue at a distance of up to 500 km from the coast.

Even more impressive canyons Bering Sea. Starting on the edge of the shelf, at a considerable distance from the coast, numerous canyons cut the continental slope here and continue for many hundreds of kilometers. A kind of "champion" is the Bering Canyon, the length of which from the top to the mouth reaches 1100 km; another "record holder" is the Zhemchug canyon, the volume of which reaches 8500 km 3 .

The position of large canyons on the continental slope is often associated with transverse faults. This determines the height and steepness of the walls of the underwater canyon. Thus, the height of the slopes of the Zhemchug canyon, associated with a graben (extended failure), exceeds 1.5 km. Naturally, collapses and landslides often occur here, gradually washed away by periodic turbidity flows.

Unlike the Congo Canyon, the canyons of the Bering Sea do not show a direct connection with the rivers flowing into it and are practically not traced in the shelf topography. However, American geologists believe that the origin of these canyons occurred during the ice age, when the shelf here was dry land and the Yukon and Kuskokwim rivers flowed through it. Now the underwater continuations of the channels on a very wide and almost horizontal shelf are almost completely covered with sediments, however, on the slope, the development of canyons under the influence of turbidity flows continues.

The largest on the planet is the Mid-Ocean Canyon in the northwestern Atlantic. Beginning in the Davis Strait between Canada and Greenland, this canyon continues south and southwest into the Baffin Sea, crossing the continental slope and ocean floor to depths of nearly 6 km in the Nares Deep Sea Basin. Unlike conventional canyons, which are oriented mostly perpendicular to the coastline, the Mid-Ocean Canyon is located almost parallel to the shores. At the same time, many smaller canyons “flow” into it from the continental slope of the Labrador Peninsula, Greenland, Newfoundland, and even Iceland (Fig. 15). In essence, this is a whole system of canyons, resembling a developed river network with numerous tributaries. The length of the main "channel" of the canyon alone exceeds 3000 km!

Submarine canyons are also characteristic of inland seas. In the Black Sea, submarine canyons are the most studied in its east coast, in the area of ​​Cape Pitsunda, where 11 relatively small submarine canyons were discovered. As the studies of Soviet scientists have shown, practically all the rivers of Transcaucasia correspond to underwater canyons, continuing to depths of 1-1.5 km and ending with alluvial fans.

Rice. 22. Steps inclined towards land on the continental slope of the Black Sea.

The waters of the Black Sea, starting from a depth of about 200 meters, contain hydrogen sulfide. In this stagnant water, devoid of oxygen, only bacteria can exist. However, on ledges, samples of bottom sediments down to a depth of 800 meters consisted of fine clayey sand with shells.

Based on the types of these shells, it was possible to determine that the age of the deposits is several tens of millennia. However, the deposits of the deeper parts of the sea show that during this period the sea, as now, was contaminated with hydrogen sulfide. Consequently, the shells lived in shallow water near the shore and were only subsequently moved to greater depths as a result of discharges.

In other samples taken at the same depths, deposits of coastal gravel and even pebbles were found. All this confirms the correctness of the guess made.

Further, even more interesting things turned out. In some soil samples obtained on the steepest parts of the continental slope, the sequence of layers turned out to be unusual. Separate layers of soil slid down the slope and crumpled and mixed along the way. Similar landslides occur on clay riverbanks in spring and rainy weather. But on seabed such phenomena were established by Acad. Arkhangelsk for the first time.

How does the slumping process take place? The layers of silt become thicker and heavier as they accumulate. Finally, their weight becomes so great that the mass of silt overcomes the friction that exists between the layers and sets in motion.

Sliding can occur for no apparent reason, but most often it begins under the influence of earthquakes. In the Black Sea, the silts are very "fat". They can start crawling on slopes as low as 2 degrees. More dense and "skinny" muds are sometimes retained on very steep slopes (up to 10 degrees), as was recently established in the seas of the Sunda archipelago.

Thus, it was found that the continental slope of the Black Sea is at least partially a series of stepped faults. As a result of these discharges, sections of the shelf relatively recently subsided by many hundreds of meters.

The largest number of earthquake sources, covering the coasts of all seas and oceans, falls, as a rule, on the area of ​​the continental slope, which once again confirms the conclusion made. Often there are sudden movements seabed. For example, during the earthquake of 1931 in the area of ​​New Foundland (North America), communication over telegraph cables laid on the seabed was instantly interrupted. When the cables were raised for repair, it turned out that they were all torn along the line of the continental slope.

A lot of such facts have been accumulated to date, and almost all geologists who have studied this issue unanimously believe that the continental slope plays an important role in the development of the earth's crust. Grandiose faults occurred along the line of the continental slope, which gave the modern look to the oceans and continents.

What is the surface of the continental slope? With the help of echo sounders, more or less pronounced irregularities are detected on it. We can say that the slope has a "blocky" structure. However, in those places where the mainland is demolished a large number of silt, the slope is relatively flat. This is due to the fact that the silt, covering the irregularities, sometimes smooths them out so much that it makes the slope gentle. Such a structure has continental slopes located against the mouths major rivers eg Amazon, Mississippi, Danube.

But in most places, silt deposits are small, and the slope is washed by strong sea currents. Here, soil tubes-shells bring stones from the bottom, sometimes with sand. It happens that the soil does not get into the instruments at all, and only animals that live attached to the rocks (anemones, hydroids, bryozoans, etc.) are raised onto the deck.

submarine canyons

In the late 60s of the last century, Russian sailors-hydrographers conducted depth measurements along the Caucasian coast of the Black Sea. Here it was required to lay a telegraph cable at depths of several hundred meters, so that neither storms nor currents could damage it. At that time, the belief prevailed that the continental slope was, as it were, an even "scree" formed by sediments. However, the measurements showed sharp jumps in depths. At the bottom there were peculiar valleys and ridges resembling a relief Caucasus mountains. These observations were published in the "Sea Collection" (1869), but they did not attract attention at the time, since the science of the relief of the seabed did not yet exist at that time.

At the beginning of the 20th century, a similar picture was discovered in Atlantic Ocean, against the mouth of the river. Congo, as well as on the continental slopes near british isles and North America. These discoveries were also made while laying telegraph cables.

Starting from the 30s of our century, when the echo sounder was widely used, more and more new information began to appear about the discovery in different places. the globe huge "ravines" running across the continental slope to a depth of two or more thousand meters (Fig. 23). Since these "ravines" sometimes look like land gorges (Fig. 24), which in America are called canyons, they began to be called "submarine canyons".

Rice. 23. Gentle underwater canyon coming from the mouth of the river. Ingur in the eastern part of the Black Sea.

Rice. 24. Comparative cross-sectional profiles of the Monterey Submarine Canyon off the coast of California (top) and the Colorado River Grand Canyon (bottom) (the vertical scale in this figure is five times the horizontal scale).

There are various theories trying to explain this incomprehensible phenomenon. According to some, underwater canyons arise as a result of the action of the so-called artesian waters, which break out under pressure from cracks in the seabed. These waters allegedly dissolve the surrounding rocks, forming "ravines" at the bottom. Others believed that the canyons were washed by special "density" currents. Turbid water is known to be slightly heavier than clear water. At the mouths of rivers flowing into large freshwater lakes, one can observe how muddy flood waters quickly flow down the slope into the depths. At the same time, they sometimes wash depressions in the form of gutters in the silt. Maybe this is how submarine canyons form. Still others believed that canyons are flooded river valleys.

Which of these theories is correct? This can only be ascertained through detailed research. It is clear, however, that the question of the origin of canyons cannot be decided on the basis of any one fact, as the authors of the theories listed above did.

A variety of methods have been applied to find out what the structure of submarine canyons is. First, a detailed measurement. An echo sounder does not always give an accurate picture of the relief of underwater canyons, since their slopes are very steep, so much so that the reflection of not only sound, but also ultrasonic waves is greatly distorted. Here I had to return to the wire lot.

Many canyons really resemble mountain river valleys. The steepness of the slopes of the canyons often reaches 20–30 degrees (Fig. 25). There are even steeper sections up to sheer ones. There are no loose deposits on these slopes. Therefore, they are composed of bedrock.

Rice. 25. Steep-sloping underwater canyon Cap-Breton in the Bay of Biscay (France).

To obtain samples of these rocks, special devices were designed that literally tore loose pieces from the rocks. It turned out that in some canyons the walls are composed of crystalline rocks, such as basalts or granites.

But what kind of river will be able to “cut through” such a deep valley in such strong rocks in a short period? It is clear that canyons are not at all the beds of flooded rivers, as some believed. Attempts were made to study the composition of the deposits of the bottom of the canyons, but a thick layer of deposits lies under the surface silt, which has not yet been penetrated.

Finally, a diver with a camera was lowered into the canyon. He penetrated to a depth of almost 100 meters and photographed sheer walls and scatterings of stones.

It was possible to establish that landslides often occur in canyons. Silts and sands quickly accumulate in the upper part of the canyon, and then, under the influence of a strong storm or earthquake, all this mass slides down the steep bottom. Therefore, the depth of the top of the canyon changes dramatically from time to time. Such phenomena were known at the end of the last century in our Black Sea.

Canyons exist along the banks of the most varied structure; often they are a continuation of river mouths. It is also characteristic that they are usually found in groups (Fig. 26). Only isolated cases of isolated submarine canyons are known. In this respect, they resemble fjords - deep gorges in the coastal zone, which form narrow and long bays in Norway, Chile, New Zealand, Chukotka and many other places.

underwater canyon

a deep valley with steep slopes, having a V-shaped transverse profile. Submarine canyons cut through the continental slope and enter the continental shelf. They are ubiquitous in the oceans.

• - canyon - a narrow and deep river valley with steep or stepped rocky sides, the bottom is entirely occupied by the bed of a river or temporary watercourse ...

  Geographic Encyclopedia

• Natural science. encyclopedic Dictionary

• - a gorge, a deep narrow valley with steep or steep slopes, often stepped ...

  Geological Encyclopedia

• - a deep river valley or gorge, usually of erosional origin, at the bottom of which a river or water stream flows, with high, often sheer cliffs ...

  Ecological dictionary

• - a deep valley with steep slopes, having a V-shaped transverse profile. Submarine canyons cut through the continental slope and enter the continental shelf...

  Marine vocabulary

• - a mining site in the west of the United States, in the state of Utah, south of the Great Salt Lake, in the suburban area of ​​Salt Lake City. 1.5 thousand inhabitants...

  Big Soviet Encyclopedia

• - a deep river valley with very steep slopes and a relatively narrow bottom, usually occupied by the riverbed ...

  Big encyclopedic dictionary

• - Loans. at the end of the 19th century. from Spanish lang., where cañon "gorge" "pipe" - Suf. the derivative will increase, character from caño "pipe" lat. canna "pipe, reed". See canister...

  Etymological dictionary of the Russian language

• - ; pl. cano/ny, R....

  Spelling Dictionary of the Russian Language

• - CANYON, -a, husband. A deep narrow valley with very steep slopes, washed out by a river flowing along its bottom...

  Explanatory dictionary of Ozhegov

• - CANYON, canyon, husband. . A deep narrow valley eroded by a river...

  Explanatory Dictionary of Ushakov

• - canyon m. A deep narrow river valley with steep, steep slopes ...

  Explanatory Dictionary of Efremova

• - Kan "...

  Russian spelling dictionary

• - geogr...

  Dictionary of foreign words of the Russian language

• - ...

  Word forms

• - gorge, valley, ...

  Synonym dictionary

"Underwater Canyon" in books

How big is the Grand Canyon?

author

How big is the Grand Canyon?

From the book The Newest Book of Facts. Volume 1. Astronomy and astrophysics. Geography and other earth sciences. Biology and medicine author Kondrashov Anatoly Pavlovich

How big is the Grand Canyon? Canyons are deep river valleys with very steep, often steep slopes and a narrow bottom, usually completely occupied by the riverbed. One of the largest canyons in the world - the Grand Canyon of the Colorado River in the United States - has a length of more than 320 kilometers,

SCRIPPS CANYON

From the book Exploration of the Ocean Depths author Shenton Edward G

Grand Canyon

From the book 100 great wonders of nature the author Wagner Bertil

Grand Canyon (USA) "... The first feeling - you see a dream. Terrifying failure!

Grand Canyon

From the book of 100 great reserves and parks author Yudina Natalya Alekseevna

Grand Canyon National Park USA Grand Canyon (Grand Canyon) is located in northwestern Arizona and covers an area of ​​4931 square meters. km. It stretches for almost 170 km along the Colorado River and a section of the Kaibab Plateau. Back in 1887, Senator B. Harrison proposed organizing

How was the Grand Canyon formed?

From the book Who's Who in the Natural World author Sitnikov Vitaly Pavlovich

How was the Grand Canyon formed? In the US state of Arizona, there is a miracle created by nature itself. It's called the Grand Canyon. If you have a good imagination, then looking at it, you can see a magical city made of stone with temples, towers and castles of the most

How was the Grand Canyon formed?

From the book Countries and Peoples. Questions and answers author Kukanova Yu. V.

How was the Grand Canyon formed? For millions of years, water has affected the substances that make up the earth's crust, breaking the most durable rocks and thereby changing the surrounding landscapes. Thus, canyons arose on Earth, the deepest of which

How big is the Grand Canyon?

From the book The Newest Book of Facts. Volume 1 [Astronomy and astrophysics. Geography and other earth sciences. Biology and Medicine] author Kondrashov Anatoly Pavlovich

How big is the Grand Canyon? Canyons are deep river valleys with very steep, often steep slopes and a narrow bottom, usually completely occupied by the riverbed. One of the largest canyons in the world - the Grand Canyon of the Colorado River in the United States - has a length of more than 320 kilometers,

How did the Grand Canyon form?

From the book All About Everything. Volume 2 the author Likum Arkady

How did the Grand Canyon form? The Grand Canyon is one of the greatest sights on the surface of the Earth. In some places, it looks like a magical city of stone with temples, towers and castles of dazzling colors. One of the most amazing things about the Canyon,

grand canyon

From the book 100 great secrets of the Earth author Volkov Alexander Viktorovich

grand canyon For millions of years, the Colorado River has carved this huge gorge through the rocks. It stretched for four and a half hundred kilometers in the northern part american state Arizona. Its depth reaches 1800 meters, and its width is from 6 to 30 kilometers. All over it

How was the Grand Canyon formed?

From the book All About Everything. Volume 3 the author Likum Arkady the author Ryansky Andrey S.

Canyon (The Canyon) An amazing place. You are swimming along an ordinary plateau, decorated with solitary corals and rather densely populated, when suddenly, right before your eyes, as if from nowhere, in the clear blue water, a curtain of rising to the surface appears.

On a sunny June morning, guided by the good wishes of our comrades, we set off on a small boat from the pier of the Sukhumi rescue station. One of us is a marine geologist, the other is a hydrologist. Our boat crossed the Sukhumi Bay and finally stopped in the sea opposite the town of Kelasuri. There, as shown by echo sounding, the bottom is cut through by a narrow and deep hollow - a canyon.

Canyons - grandiose underwater gorges - stretch along the bottom where the underwater continuations of the continents descend steeply to the bed of the seas and oceans. They often begin near the land itself and go perpendicular to the coastline to depths of more than two kilometers. Steep walls of underwater gorges are cut into the bottom of the sea by 200 meters or more.

The canyons of the ocean floor are enormous and rival the largest valleys and canyons on land, such as the Grand Canyon of Colorado in North America. There are smaller canyons in the Black Sea. They cross the continental slope of the Caucasian coast. Many of them start near the coast at a depth of 20-25 meters and end at a depth of 500-700 meters.

In the science of the structure of the seabed, the section devoted to submarine canyons invariably causes heated debate. Until now, scientists remain mysterious about their origin.

What force could create these deep and long hollows at the bottom? Judging by the deposits into which the canyons are cut, they apparently formed in the Quaternary, that is, a little over a million years ago. On land, such hollows are created by rivers. But there are no rivers at the bottom of the oceans. Ocean currents usually do not penetrate to great depths, capturing only surface water. Yes, most currents do not have enough speed to erode the bottom so much.

Some scientists put forward the following hypothesis: submarine canyons formed on land and only then were flooded by the sea. But geologists rebelled against these statements: such a grandiose, at least 100 meters, relatively recent and widespread rise in ocean level could not have occurred; it would not have gone unnoticed, and geologists do not find traces of such changes.

Then they began to put forward other, sometimes curious and fantastic, assumptions. Their presentation would probably take up several thick volumes. For example, the following hypothesis was proposed: submarine canyons are formed by waves that occur during underwater earthquakes. These giant waves, tsunamis, really produce huge destruction on the shores. The whole world is aware of the recent tsunami damage on the coast of Chile. However, these waves quite rarely occur on the same sections of the coasts and affect mainly the coast and the shallow water of the bottom. At a depth of more than 100 meters, tsunamis are practically not felt. This hypothesis is refuted by such a simple fact that many large canyons are located in areas where tsunamis are not observed, and, on the contrary, where tsunamis are frequent, there are often no canyons.

The American scientist Johnson expressed the idea that canyons are formed in those places where artesian sources come out at the bottom. Groundwater, according to Johnson, coming out under pressure on the continental slope, erodes or dissolves the rocks that make up the bottom. But even this theory does not withstand serious criticism, since canyons are sometimes located in such geological conditions where it is impossible to assume the dissolution of the rocks of the continental slope.

Two hypotheses are now the most popular: the first is about the tectonic origin of canyons, the second is about their formation under the influence of the so-called turbidity, or suspension, currents. Supporters of the first claim that as a result of subsidence of the ocean floor, the continental slope cracked and the canyons are grandiose tectonic cracks. It is known that similar cracks also occur on land when the earth's crust sinks or rises. Therefore, the statements of supporters of the tectonic origin of underwater gorges sound very plausible.

However, some scientists, and among them such prominent geologists as the American F. Schipard and the Frenchman J. Bourcart, still do not recognize the tectonic theory. In their opinion, many geological facts testify against it. For example, between canyons and geological structures seabed is sometimes not observed compliance. Many of the canyons are winding and shaped more like torrential valleys than tectonic fissures.

And what do supporters of the theory of canyon formation under the action of turbidity currents say? Sea water, enriched with silt particles, sinks to the bottom and flows down the continental slope in streams, cutting deep gorges.

However, this theory, as well as the tectonic one, has many opponents who, with facts in hand, and, I must say, quite weighty ones, refute it. In a word, a situation was created when almost every scientist began to put forward his own hypothesis of the origin of the mysterious canyons and refute everything else.

When the opportunity presented itself to visit one of the canyons, to see it with our own eyes, we, of course, could not deny ourselves such a pleasure. We were also concerned about an important problem that had practical significance. It is known that the Caucasian coast of the Black Sea is strongly destroyed by waves. Wide beaches, which are formed at the foot of coastal ledges from sand and pebbles carried by rivers, could save the coast from destruction. But the beaches in the Caucasus do not increase, but, on the contrary, decrease; Coastal erosion is becoming an increasingly formidable phenomenon. The question arose before scientists: where does all the detrital material that the rivers carry out disappear? It was suggested that the culprit should be sought in the depths, at the bottom of the sea: apparently, pebbles and sand, moving under the action of waves along the coast, fall to the tops of the canyons and roll down to great depths along their channels. Is it so?

The first attempt to descend into the canyon was unsuccessful. At a depth of 25 meters, solid black darkness surrounded us from all sides. It was not visible any air bubbles escaping from the scuba gear, nor the figure of a comrade swimming nearby. Holding on to the rope, we went down to the bottom and literally fell into liquid sticky silt. It was useless to stay at depth: nothing could be seen. Are all the Black Sea canyons shrouded in darkness? Or did we fail because we plunged into the Poti canyon, where the muddy waters of the Rioni flow? And so we decided to go down to another canyon - Kelasuri.

We put on thick diving sweaters and scuba gear. Take a depth gauge and an underwater compass. The helmsman Dima checks the landmarks on the shore for the last time and shouts: “Guys, it's ready! Break a leg!"

Hand in hand, we quickly began to sink. Through the cloudy milky water we can hardly distinguish each other.

The lower, the colder and clearer the water. Suddenly buried in a muddy bottom, raising a cloud of turbidity. Monotonous light brown plain. The bottom surface is dotted with many round holes dug in the mud by polychaete worms. Having determined the direction by the compass, we sail to the north half a meter from the bottom.

Finally, at a depth of 25 meters - a sharp inflection of the bottom surface. We rush down, and suddenly a steep slope of an underwater canyon opens up in front of us.
The cold is breathtaking. But as the water temperature drops, visibility improves dramatically.

This is what happens when you step out of a semi-dark room on a bright spring evening.

At a depth of forty-five meters, visibility became quite good. The violet-blue color of the water seemed to be sharply perceived not only by the eyes, but by the whole being, giving a real feeling of great depth. In the transparent thickness, small jellyfish seem to soar. Their openwork domes move in slow jerks.

10 meters from us - the slope of the canyon. It is dissected by small but deep ruts. The slope is very steep, in some places sheer, and thin layers of compacted silt are exposed in steep ledges from under soft silt. You can see small circuses cut into the slope in a semicircle. Apparently, they arose at the sites of landslides. Separate blocks of dense silt act as bizarre sharp-edged ribs.

We slowly slide down to the bottom of the canyon. He steeply goes into the inky abyss. Damn cold. The water temperature here is about seven degrees Celsius. Attention is increasingly focused on their own feelings. Hearing sharply sharpens. Every slight sound takes on a harsh metallic hue. You can clearly hear how the parts of the lung machines work loudly and how the air with a whistling noise passes through the airways and fills the lungs.

The slope of the canyon becomes less steep, and here we are at the bottom of the gorge. The dim arrow on the dark dial of the depth gauge crossed the mark of 70 meters (Only divers who have undergone special training go down to such depths.).

The almost flat bottom of the canyon, 15 meters wide, is sandwiched between steep slopes. It is lined with a layer of semi-liquid silt. Here, among the silt, lies a small shell of a dead rapana, then a boulder with a diameter of about 20 centimeters and several separately lying pebbles.

Suddenly our attention is attracted by a bright yellow object lying at the bottom. Have we become victims of deep intoxication? Half-meter yellow crocodile on the 4th day of the canyon. What an obsession! Mirage does not disappear. We swim up to the crocodile with a feeling of deepest amazement, we grab it by the torso. In the hands - the most ordinary children's Crocodile Krokodilovich, made of celluloid. Here's an unexpected trophy!

While one is hiding this funny gift from the sea, the other is trying to determine the density of bottom silt: a hand with a little effort enters it up to the elbow...

When we went upstairs, the helmsman Dima looked at his watch: the dive lasted 17 minutes.

What did we manage to find out in the canyon? No, pebbles from the Black Sea beaches do not go into the canyons in large quantities. Those who explained the erosion of the coast were right not by underwater, but by purely terrestrial causes. The regulation of the river systems of the Caucasus has led to the fact that the rivers have become shallower. They erode the banks in the upper reaches less and bring less pebbles to sea ​​shores. At the same time, on the beaches themselves, the pebbles are intensively worn out. A lot of it is taken out from the beaches by economic organizations for the needs of construction. About what huge harm the unreasonable removal of pebbles from the beaches brings, has already been repeatedly mentioned in our press. This means that the main method of combating coastal erosion should be not fencing the tops of the canyons, but artificial fixing of the beaches and protecting them from plunder.

It remains for us to say what our observations have yielded for the theory. The hypothesis of the tectonic origin of the canyon is unacceptable in this case, since it assumes that canyons are ancient landforms preserved at the bottom of the sea. But we have seen with our own eyes that the slopes of the canyon have fresh ledges and ruts and remain very steep, despite the fact that collapses constantly occur on them. If, under modern conditions, the channel of the canyon had not been constantly washed out, then for decades this hollow would have been completely covered with silt.

It is impossible to explain the formation of canyons in the Black Sea by the action of artesian sources and tsunami waves. There are no such phenomena in this area.

According to our assumption, special natural currents that occur in the coastal part of the sea can wash out the canyons. These currents act during storms, when masses of sea water come up to the shore and return to the sea along the bottom, moreover, in the form of separate powerful jets.

Some swimmers are familiar with similar currents. If a bather gets into a powerful jet of current, he will certainly be carried far into the sea. In such cases, it is useless to swim to the shore, the only salvation is to cross the stream and swim ashore in another place.

The study of such currents began relatively recently, and their role in the erosion of the bottom has not been elucidated. Perhaps their power is such that they, at least in the conditions of the Black Sea, can wash canyons? However, such an assumption can now be made only as a hypothesis. Further research needs to be done.

V. Bogdanov, P. Kaplin