The deepest depressions on earth. Plains: characteristics and types Landforms of land

05.03.2020

Humanity has a special relationship with mountains. They are conquered by climbers, poets sing, artists and photographers capture them. The antipode of peaks - deep depressions on the earth's surface, in comparison with them, is greatly ignored. Only the Mariana Trench confidently comes to mind from geography lessons, well, at best, the deepest lake - Baikal. This is largely due to the fact that it is easier to climb 5 kilometers than to descend 500 meters. First of all, technical solutions, equipment, equipment, and financial costs are incomparable. One of the famous people said that humanity has studied space better than the oceans. But there are depressions on land, it is worth learning about some in more detail.

Dead Sea Valley

It is also called the Salt Sea. Its surface is 422 meters below the long-term average level of the Baltic Sea, which is accepted in Russia as a zero mark. It is considered the lowest mark on land. Like Baikal, the sea was formed as a result of tectonic changes more than 2 million years ago. The length of the sea is about 70 km, and the width is up to 18 km. Maximum depth - 368 m.

The lake is located in the south of Eastern Siberia. Its surface today is 456.22 m above sea level. Formed over 25 million years ago. The depth of the fault in the earth's crust reaches 6–8 km and is mostly filled with sediments. It is considered the oldest lake and the largest natural reservoir of fresh water on Earth. The quality due to the absence of impurities approaches distilled water. Its dimensions:

Length - 636 km.
Width - up to 80 km.
Maximum depth - 1642 m(according to recent research).

In the summer of 2009, it was actively studied using Russian-made Mir deep-sea manned submersibles. In addition to scientists, many famous people took part in the dives, including V.V. Putin, who gave an interview to journalists from a depth of 1400 m.

The lake in Africa is comparable with Baikal in all respects and is similar in origin. Located at an altitude of 773 m. Length - 650 km, the width reaches 72 km. The maximum depth is 1470 m.
Caspian Sea
The surface of a huge reservoir is located at around 28 meters below the level of the Baltic. Because of its size and salty water, the ancient inhabitants of Europe and Asia considered it an ocean. The depth reaches 1025 m.

Rivaling the Amazon for the top spot on the planet in terms of the volume of water it carries, the Congo is the only great river to cross the equator twice. But she is also amazing in the depths in the lower reaches, where she created the waterfalls of Livingston. There, the distance from the surface to the bottom reaches 230 m than no other river in the world can boast.

Its total length reaches 446 km. Maximum depth reaches 1.8 km. The greatest canyon is located in the territory of the national park in the state of Arizona. The walls of the gorge are a real geological and archaeological museum, as they are witnesses of four geological epochs in the history of the planet.

It is also located in Arizona. According to the research and calculations of scientists, the crater is the result of a meteorite hitting the Earth weighing two million tons, consisting of a substance with a high content of iron and nickel. Today its dimensions are:

Diameter - 1220 m.
The height of the shaft around the crater is up to 50 m.
Max Depth 184 m.

According to one of the many theories, he is the culprit of the death of dinosaurs.

Bentley Trench, Antarctica

Under the ice dome of the sixth continent, the deepest place on the Earth, not covered by ocean water, is hidden from human sight. True, it can only be attributed to land conditionally. Scientists discovered it recently - in 1961. The depth of the depression was 2555 meters which is impressive.
By the way, few people know that Antarctica is not only a lifeless ice plateau on which sleigh trains crawl from station to station, but also huge mountains. Such, for example, as:

Vinson - 4892 m.
Kirkpatrick - 4528 m.

Now we can move on to the really deepest depressions on Earth - the ocean.

The Pacific Ocean is not only the largest in area, but also the deepest. The dimensions of many depressions at the bottom are simply amazing - from 8 to 10 km. The study of most of them became possible only in the second half of the last century due to technical complexity.

The record holder is the famous Mariana Trench. It is located near Japan. The length of this underwater trench exceeds 1500 km. In 1960, for the first time, she submitted to the technical achievements and courage of people who decided to dive. The water pressure per 1 cm of the surface of the descent vehicle reached 1100 kg. In 2011, scientists using the latest sonar equipment recorded a maximum depth of 10,994 m. In March 2012, the famous director and explorer Cameron, in a single-seat deep-sea submersible, plunged to a depth of 10,898 m, filming unique material for his new film using various video equipment.

man-made hollows

Mankind, as a result of its industrial and research activities, has created over the centuries many pits, mine workings, mines, quarries, and wells. Some of them are comparable in size to the activities of nature. Here are some of them:

The Kimberley place in Africa, which has become a household name for diamond deposits. The quarry is called Big Hole. Gemstone miners dug 240 meters deep, manually throwing 28 million tons of sifted soil to the surface from 1866 to 1914, extracting almost 3 tons of diamonds.
Diamond quarry Mir in Yakutia. The dimensions reached 1.2 km in diameter with a maximum depth of 525 m.
Bingham Canyon. This polymetallic ore deposit is located in the US state of Utah. Development has been carried out since 1863 to the present day in an open way. During this time, the width of the quarry has reached 4 km, and the depth is 1200 m. It is considered the largest in the world.
Towton mine. Located in South Africa. The working depth is 4 km.
Superdeep well SG-3, which was completed in 1970 in the Murmansk region, reached a mark of 12,262 m.
Today, this is the maximum depth reached by mankind in the study of the Earth's surface. But there is no limit to discoveries and research. After all, mankind, given the size of the planet and the thickness of the hard shell - the lithosphere, figuratively speaking, could not even pierce the skin of an apple.

Landform classifications

There are several classifications of landforms of the Earth, which have different bases. According to one of them, two groups of landforms are distinguished:

positive - convex in relation to the plane of the horizon (continents, mountains, hills, hills, etc.);
negative - concave (oceans, basins, river valleys, ravines, beams, etc.).

The classification of the forms of the Earth's relief by size is presented in Table. 1 and in fig. one.

Table 1. Landforms of the Earth by size

Rice. 1. Classification of the largest landforms

We will separately consider the relief forms characteristic of the land and the bottom of the World Ocean.

The relief of the Earth on the map of the World

Ocean floor landforms

The bottom of the World Ocean is divided by depth into the following components: continental shelf (shelf), continental (coastal) slope, bed, deep-sea (abyssal) basins (troughs) (Fig. 2).

continental shelf- the coastal part of the seas and lying between the coast and the continental slope. This former coastal plain in the topography of the ocean floor is expressed as a shallow, slightly hilly plain. Its formation is mainly associated with the subsidence of individual land areas. This is confirmed by the presence of underwater valleys, coastal terraces, fossil ice, permafrost, remnants of terrestrial organisms, etc. within the continental shallows. Continental shallows are usually distinguished by a slight bottom slope, which is practically horizontal. On average, they drop from 0 to 200 m, but depths of more than 500 m can occur within their limits. The relief of the continental shoal is closely related to the relief of the adjacent land. On mountainous coasts, as a rule, the continental shelf is narrow, and on flat coasts it is wide. The continental shelf reaches its greatest width off the coast of North America - 1400 km, in the Barents and South China Seas - 1200-1300 km. Typically, the shelf is covered with clastic rocks brought by rivers from land or formed during the destruction of the coast.

Rice. 2. Landforms of the ocean floor

Continental slope - the inclined surface of the bottom of the seas and oceans, connecting the outer edge of the continental shoal with the ocean floor, extending to a depth of 2-3 thousand m. It has rather large angles of inclination (on average 4-7 °). The average width of the continental slope is 65 km. Off the coast of coral and volcanic islands, these angles reach 20-40°, and near the coral islands there are angles of greater magnitude, almost vertical slopes - cliffs. Steep continental slopes lead to the fact that in the areas of maximum inclination of the bottom, masses of loose sediments slide down to the depths under the action of gravity. In these areas, a bare sloping bottom can be found.

The relief of the continental slope is complex. Often the bottom of the continental slope is indented by narrow deep canyon gorges. They often visit steep rocky shores. But there are no canyons on continental slopes with a gentle slope of the bottom, and also where there are islands or underwater reefs on the outer side of the continental shelf. The tops of many canyons adjoin the mouths of existing or ancient rivers. Therefore, canyons are considered as an underwater continuation of flooded riverbeds.

Another characteristic element of the relief of the continental slope are underwater terraces. These are the underwater terraces of the Sea of Japan, located at a depth of 700 to 1200 m.

Ocean bed- the main expanse of the bottom of the World Ocean with prevailing depths of more than 3000 m, extending from the underwater margin of the mainland into the depths of the ocean. The area of the ocean floor is about 255 million km 2, i.e., more than 50% of the bottom of the World Ocean. The bed is distinguished by insignificant angles of inclination, on average they are 20-40 °.

The relief of the ocean floor is no less complex than that of the land. The most important elements of its relief are abyssal plains, oceanic basins, deep-sea ridges, mid-ocean ridges, uplands and underwater plateaus.

In the central parts of the oceans are located mid-ocean ridges, rising to a height of 1-2 km and forming a continuous ring of uplifts in the Southern Hemisphere at 40-60 ° S. sh. Three ridges extend northward from it, extending meridianally, in each ocean: the Mid-Atlantic, Mid-Indian and East Pacific. The total length of the Middle Oceanic Ranges is more than 60,000 km.

Between the mid-ocean ridges are deep-sea (abyssal) plains.

abyssal plains- smooth surfaces of the bottom of the World Ocean, which lie at depths of 2.5-5.5 km. It is the abyssal plains that occupy approximately 40% of the ocean floor area. Some of them are flat, others are wavy with a height amplitude of up to 1000 m. One plain is separated from the other by ridges.

Some of the solitary mountains located on the abyssal plains protrude above the surface of the water in the form of islands. Most of these mountains are extinct or active volcanoes.

Chains of volcanic islands above a subduction zone, where one oceanic plate subducts under another, are called island arcs.

In shallow waters in tropical seas (mainly in the Pacific and Indian Oceans), coral reefs are formed - calcareous geological structures formed by colonial coral polyps and some types of algae that can extract lime from sea water.

About 2% of the ocean floor is deep-water (over 6000m) depressions - gutters. They are located where the oceanic crust subducts under the continents. These are the deepest parts of the oceans. More than 22 deep-sea basins are known, 17 of them are in the Pacific Ocean.

landforms

The main landforms on land are mountains and plains.

The mountains - isolated peaks, massifs, ridges (usually more than 500 m above sea level) of various origins.

In general, 24% of the earth's surface is covered by mountains.

The highest point of the mountain is called mountain top. The highest mountain peak of the Earth is Mount Chomolungma - 8848 m.

Depending on the height, the mountains are low, medium, high and highest (Fig. 3).

Rice. 3. Classification of mountains by height

The highest mountains of our planet are the Himalayas, the Cordilleras, the Andes, the Caucasus, the Pamirs can serve as an example of high mountains, the Scandinavian Mountains and the Carpathians are medium, and the Ural Mountains are low.

In addition to the mountains mentioned above, there are many others on the globe. You can get acquainted with them on the maps of the atlas.

According to the method of formation, the following types of mountains are distinguished:

folded - formed as a result of crushing into folds of a thick layer of sedimentary rocks (mainly formed in the Alpine era of mountain building, therefore they are called young mountains) (Fig. 4);
blocky - formed as a result of raising to a great height of hard blocks of the earth's crust; characteristic of ancient platforms: the internal forces of the Earth split the rigid foundation of the platforms into separate blocks and raise them to a considerable height; as a rule, ancient or revived) (Fig. 5);
folded-blocky - these are old folded mountains that have largely collapsed, and then, in new periods of mountain building, their individual blocks were again raised to a great height (Fig. 6).

Rice. 4. Formation of folded mountains

Rice. 5. Formation of old (blocky) mountains

According to the location, epigeosynclinal and epiplatform mountains are distinguished.

By origin, mountains are divided into tectonic, erosional, volcanic.

Rice. 6. Formation of fold-block renewed mountains

tectonic mountains- these are mountains that were formed as a result of complex tectonic disturbances of the earth's crust (folds, thrusts and various kinds of faults).

Erosive mountains - high plateau-like areas of the earth's surface with a horizontal geological structure, strongly and deeply dissected by erosion valleys.

Volcanic mountains - these are volcanic cones, lava flows and tuff covers distributed over a large area and usually superimposed on a tectonic base (on a young mountainous country or on ancient platform structures, such as volcanoes in Africa). Volcanic cones formed by accumulations of lava and rock fragments erupted through long cylindrical vents. These are the Maoin mountains in the Philippines, Mount Fuji in Japan, Popocatepetl in Mexico, Misty in Peru, Shasta in California, etc. Thermal cones have a structure similar to volcanic cones, but are not so high and are composed mainly of volcanic slag - a porous volcanic rock that looks like ash.

Depending on the areas occupied by mountains, their structure and age, mountain belts, mountain systems, mountainous countries, mountain prices, mountain ranges and uplifts of a smaller rank are distinguished.

mountain range called a linearly elongated positive landform, formed by large folds and having a significant length, mostly in the form of a single watershed line, along which the most
significant heights, with clearly defined ridges and slopes facing in opposite directions.

Mountain chain- a long mountain range, elongated in the direction of the general strike of the folds and separated from adjacent parallel chains by longitudinal valleys.

mountain system- formed during one geotectonic epoch and having spatial unity and a similar structure, a set of mountain ranges, chains, highlands(extensive mountain uplifts, which are a combination of high plains, mountain ranges and massifs, sometimes alternating with wide intermountain basins) and intermountain depressions.

Mountain country- a set of mountain systems formed in one geotectonic epoch, but having a different structure and appearance.

mountain belt- the largest unit in the classification of mountain relief, corresponding to the largest mountain structures, combined spatially and according to the history of development. Usually the mountain belt stretches for many thousands of kilometers. An example is the Alpine-Himalayan mountain belt.

Plain- one of the most important elements of the relief of the land surface, the bottom of the seas and oceans, characterized by small fluctuations in heights and slight slopes.

The scheme of formation of plains is shown in fig. 7.

Rice. 7. Formation of plains

Depending on the height, among the land plains, there are:

lowlands - having an absolute height from 0 to 200 m;
elevations - not higher than 500 m;
plateaus.

Plateau- a vast area of relief with a height of 500 to 1000 m or more, with a predominance of flat or slightly undulating watershed surfaces, sometimes separated by narrow, deeply incised valleys.

The surface of the plains can be horizontal and inclined. Depending on the nature of the mesorelief that complicates the surface of the plain, flat, stepped, terraced, undulating, ridged, hilly, hilly, and other plains are distinguished.

According to the principle of the predominance of existing exogenous processes, the plains are divided into denudation, formed as a result of the destruction and demolition of previously existing uneven terrain, and accumulative resulting from the accumulation of loose sediments.

Denudation plains, the surface of which is close to the structural surfaces of a slightly disturbed cover, are called reservoir.

Accumulative plains are usually subdivided into volcanic, marine, alluvial, lacustrine, glacial, etc. Accumulative plains of complex origin are also common: lacustrine-alluvial, delta-marine, alluvial-proluvial.

The general features of the relief of the planet Earth are the following:

Land occupies only 29% of the Earth's surface, which is 149 million km2. The bulk of the land mass is concentrated in the Northern Hemisphere.

The average land height of the Earth is 970 m.

On land, plains and low mountains up to 1000 m high prevail. Mountain elevations above 4000 m occupy an insignificant area.

The average depth of the ocean is 3704 m. The relief of the bottom of the World Ocean is dominated by plains. The share of deep-sea depressions and trenches accounts for only about 1.5% of the ocean area.

Nature never ceases to amaze us with its magnificent phenomena, such as these inexplicable depressions in the earth. These holes, which can be found all over the world, form gradually or can appear suddenly.

1 Dean's Blue Hole, Bahamas

Dean's Blue Hole is the world's deepest abyss filled with salt water. Its depth reaches 202 m, and it is located in a bay to the west of the city of Clarence in Long Island, in the Bahamas. Dean's Blue Hole is named after a family of local landowners. It is located in a small bay, separated from the open sea by a small peninsula. Over the past few years, this cavity has become a world-class freediving center.

2. Biman Karst Depression, Oman

This karst depression was formed naturally when soil collapsed over unstable soil layers. An underwater tunnel departs from the funnel, leading to the sea, located 500 meters away. The constant flow of sea water causes fresh and sea water to mix in the funnel. It is possible to dive here, but this should be done with caution due to strong tides. The sinkhole is located about 6 km from Dibab and is separated from it by the road from Muscat to Sur, which runs along the coast. At the moment, a large highway is being built next to the sinkhole.

3. Great Blue Hole, Belize

The Great Blue Basin is a huge underwater sinkhole off the coast of Belize. It is located near the center of the Lighthouse Reef, a small atoll located 70 km from the mainland and the city of Belize. The depression is round in shape, with a diameter of more than 300 m, and its depth is 124 m. The Great Blue Depression, which is part of the Belize Barrier Reef, is under the protection of UNESCO as part of the World Heritage Site. The site is popular with divers who are attracted by the opportunity to dive into the crystal clear waters and see different types of fish, including giant groupers, baleen nurse sharks and several types of reef sharks, such as the Caribbean reef shark and black tail shark.

4. Ik Kil, Mexico

Ik Kil is a famous sinkhole located near Piste in the municipality of Tinum (Yucatan, Mexico). It is located in the northern center of the Yucatan Peninsula and is part of the Ik Kil archaeological park near Chichen Itza. It is open to the public, swimming is allowed, and there are frequent bus tours. The funnel is located in the open air and goes down 26 meters. A carved staircase leads down to the diving platform. The diameter of Ik Kil is about 60 meters and the depth is about 40 meters. Vineyards that reach the edge of the funnel stretch their vines down to the water's edge, where they are washed by small waterfalls that run along the walls. In addition, frolicking black catfish can be seen in the funnel.

5. Red Lake, Croatia

Red Lake is a depression enclosing a karst lake near the town of Imotski, Croatia. It is known for its numerous caves and strikingly high cliffs, reaching 241 meters above sea level and going under water. The depth of this depression is estimated to be approximately 530 meters, and the volume is 25-30 million cubic meters. Such impressive dimensions allow it to be the third largest depression in the world. Water flows out of the lake through groundwater, the paths of which go lower than the bottom of the lake itself.

6. Sunset, Mexico

Zakaton is a karst basin filled with thermal water that belongs to the Zakaton system, a group of unusual karst formations located in the municipality of Aldama in the northeastern state of Tamaulipas (Mexico). It is the deepest depression of all known depressions in the world filled with water - its depth is 339 meters. Zakathon is the only one of the five depressions located on Rancho La Azoufrosa that has a noticeable flow of water. Zakathon takes its name from the free-rolling forage grass bushes (zacate) that move across the ground driven by the wind.

7. Morning Splendor Pool, Wyoming, USA

This is one of the most popular and beautiful thermal pools in Yellowstone Park. The depth of this pool is 4 meters. The Morning Glory pool got its name in 1880 for its resemblance to the Morning glory flower. The unusual color of the pool is associated with bacteria that live in the water. However, once the pool was in danger of losing its color when the Great Circular Road ran next to it. Proximity to the pool increased the likelihood that thoughtless patrons would throw coins into it, thereby causing the pool to cool and endangering the existence of the bacteria that live in it and give it color. Today, to get to the Morning Splendor pool, you need to walk along the Upper Geyser Basin, but the walk is undoubtedly worth the effort.

8. Neversink Depression, Alabama, USA

Neversink Depression is a limestone cave in Alabama. It is one of the most photographed depressions in the world due to its waterfalls and beautiful fern-covered ledges. At the top, the diameter of the depression is about 12 m, but it widens downward and reaches 30 m at the bottom, which is 50 m from the ground. Neversink is home to bats and several rare and endangered species of ferns.

9. Giant cauldron in Rovaniemi, Finland

The gigantic cauldron in Rovaniemi is one of the most interesting places in Finland. The gigantic cauldron has a diameter of 5.7-8 meters and a height of almost 15 meters.

10. Balaa sinkhole, Lebanon

The Balaa sinkhole is located in northern Lebanon. This is a funnel about 250 meters deep. The most amazing feature of this depression is the waterfall that seeps from one of its sides, creating three natural bridges one over the other.

Bonus: Man-made Great Kimberley Basin, South Africa

Kimberley is home to the De Beers United Diamond Mining and the capital of the world's diamond industry, home to some of the richest diamond mines in the world. The place became the center of the diamond rush, when in 1871 a diamond was found on the small hillock of Kolsberg Koppi. A few months after the start of excavations, more than 30,000 people randomly dug up a piece of land measuring 200 by 300 meters in search of diamonds. They quickly swept the hill and plunged down to 1100 meters, thus creating the large depression that we know now. 28 million tons of earth have been excavated to extract 14.5 million carats of diamonds. It was here that the famous diamond of 83.5 carats called the "Star of Africa" was found.

1 Dean's Blue Hole, Bahamas

Dean's Blue Hole is the world's deepest abyss filled with salt water. Its depth reaches 202 m, and it is located in a bay to the west of the city of Clarence in Long Island, in the Bahamas. Dean's Blue Hole is named after a family of local landowners. It is located in a small bay, separated from the open sea by a small peninsula. Over the past few years, this cavity has become a world-class freediving center.