Mountains are the most picturesque regions of the world. Majestic and beautiful are the peaks of the Tien Shan, the Caucasus, the Alps sparkling with eternal snows, the impregnable snow-white masses of the Himalayas; the harsh ridges of the Urals are also beautiful, crowned with intricately weathered rocks rising like watchtowers above the chaos of boulders; green slopes and valleys of the Carpathians with fast-flowing rivers are good.
Mountains attract people not only for their beauty. In their depths are hidden ore riches, with the extraction and use of which the cultural development of mankind is connected. Fast mountain - a powerful source of energy. Clean mountain air and a variety of which young mountains are especially rich in restore the strength and health of sick and tired people.
You can get to know the structure of mountains quite well without laying boreholes and without digging deep mines: the structure of mountains is revealed in gorges and on exposed slopes in river valleys.
Let's make a mental journey through the river valleys Northern Urals and get acquainted with the structure of this ridge. To cross the Northern Urals, one must take a boat up one of the tributaries of the Pechora that escapes from it, cross the mountain watershed on foot and go down on a raft along one of the rivers of the eastern slope belonging to the basin of the river. Obi. On the banks of the Ural rivers act picturesque rocks and exposed cliffs, or outcrops. You will see that they are composed of sedimentary rocks: limestones, sandstones, conglomerates, clay and siliceous shales. In these rocks there are imprints and fossilized remains of extinct organisms; they are especially numerous in limestones.
Limestone deposits indicate that millions of years ago there was an open, shallow warm area, at the bottom of which there were marine animals that had calcareous skeletons.
Sandstones with the remains of marine organisms and plant imprints, which are visible here, were deposited in the area of the sea coast or sea islands, and sandstones and clays with the remains of plants and freshwater - river or lake sediments. In the coastal outcrops of the rivers of the western slope of the Urals, layers of marine sediments protrude mainly.
The remains of organisms found in rocks make it possible not only to determine the conditions under which these rocks were formed, but also make it possible to find out which of the layers were deposited earlier and which later.
Geologists divide the history of the Earth into five major periods of time, or eras: the Archeozoic (the era of ancient life), the Proterozoic (the era of primary life), the Paleozoic (the era ancient life), Mesozoic (the era of middle life) and Cenozoic (the era of new life). The duration of eras is measured in hundreds of millions of years. They, in turn, are divided into periods, the duration of which is measured in tens of millions of years.
The study of the fossil remains of animals and plants found in the strata that make up the Ural Range shows that they were deposited during the Paleozoic era of the Earth's history. As you move east, layers of more and more ancient sediments of the Paleozoic era will appear in the coastal rocks of the Ural rivers.
Along the westernmost outskirts of the Urals stretches from north to south a strip of sediments formed in the last, Permian period of this era. The rocks deposited at the beginning of the Permian period consist of sandstones, conglomerates and shales with marine fauna, and the sediments of the second half of the Permian period were formed not in the sea, but in rivers and lakes; they contain the remains of plants, freshwater mollusks and fish, and in one outcrop on the shore of the Upper Pechora, bones of large extinct reptiles were found.
In the Polar Urals, in the basin of the tributary of the Pechora river. Mustache, among the Permian deposits are numerous seams of coal. Here in 1926 prof. A. A. Chernov discovered the richest coal-bearing Pechora basin. Within the Upper Pechora, the Permian deposits do not contain coal at all. But deposits of rock salt and valuable potash salts have been discovered here.
The thickness of the Permian deposits on the western slope of the Northern Urals is very high; it reaches several kilometers.
Further east of the band of Permian rocks in the foothills of the western slope of the Urals, a band of deposits of the Carboniferous period that preceded the Permian extends. It is mainly with the remains of marine animals. In these regions of the Urals, the places are especially picturesque. Looking closely at the water-smoothed surface of limestone, one can, as it were, look at the bottom of the carboniferous, where various shells, large colonies of corals or whole layers of rocks, consisting of segments of stems of sea lilies and needles, are visible. sea urchins. Looking through a magnifying glass, you can be sure that it often consists entirely of the smallest shells of rhizomes - foraminifers.
Among the deposits formed at the beginning of the Carboniferous period, in addition to limestones, there are layers of sandstones with plant remains, and in some places with layers of coal. This means that at that time there was a shallowing of the sea and in some places land appeared, covered with rich vegetation, which provided material for the formation of coal.
Behind the band of carboniferous limestones, an area of more ancient deposits appears - the Devonian, and then the Silurian periods. They also consist partly of limestones, partly of sandstones. Among them are siliceous and - monuments of the deeper regions of the sea.
Examining the rocks of the Paleozoic rocks protruding along the banks of the rivers, one can notice that the layers do not lie horizontally. Limestone strata in coastal cliffs are usually inclined, or "fall", in one direction or another at a smaller or larger angle to the horizon. Sometimes the layers are vertical. These. inclined and vertical layers are parts of large, dilapidated folds. The sizes of the folds are very diverse: from the smallest, measured in centimeters, to the huge ones, having tens of kilometers in length, hundreds and thousands of meters in width. Such large folds can form high mountain ranges.
The most ancient and most altered sediments form the main Ural Range. Looking at the exposed rocks and scree on the peaks Ural mountains, you can see crystalline schists formed as a result of changes in sedimentary rocks, mica schists, less often marbles. It is often possible to observe how these rocks are interbedded with green shales of a different origin, formed due to the metamorphism of basaltic lavas.
It is assumed that the ancient crystalline schists of the Urals belong to the deposits of the Cambrian period and even part of the Proterozoic era.
A number of peaks of the Ural Mountains consist of deep igneous rocks: granites, gabbro, etc.
In the area of ancient shales of the mountain strip, especially where granites and gabbro are common, there are various ore deposits for which the Urals are so famous. There are lead and zinc ores, and a number of other metals.
On the eastern slope of the Urals, the area of Paleozoic deposits is again opened. They will differ from the sediments of the western slope corresponding to them in age by abundance.
At the very outskirts of the eastern foothills of the Urals, on their border with the vast West Siberian lowland, younger deposits emerge, formed during the Mesozoic and Cenozoic eras. These marine and continental sediments are covered with Ice Age Quaternary rocks. Unlike Paleozoic deposits, they lie horizontally.
What can be said about the origin Ural Range based on what you saw while crossing it?
In what direction did the forces that caused the folding act? Oblique, overturned and recumbent folds in the mountains directly indicate in which direction the forces that crushed the layers acted. Such folds undoubtedly formed under the influence of lateral, horizontal pressure. This pressure was most often one-sided, since in each mountainous region the folds usually overturn and lie down in one predominant direction. On the western slope of the Urals, the folds are tilted and overturned to the west under the influence of pressure that came from the east. A straight crease can result from pressure both from the bottom up and from the sides, in a horizontal direction. This is easy to verify with a simple experiment. If you put a stack of sheets of paper on the table, bring a stick under it and lift it, then the paper will bend; and forms a straight line anticlinal fold. The same fold can be obtained by carefully squeezing sheets of paper lying on the table from both sides with your hands. As can be seen, the folds are formed as a result of the disruption of the original bedding. Such disturbances in the occurrence of earth layers are called dislocations.
As can be seen, the Ural Range is composed of a thick layer of Paleozoic sedimentary rocks and almost exclusively marine origin. Among the latter, there are many erupted volcanic rocks in the mountain belt and on the eastern slope. This indicates that in the place of the Urals in the Paleozoic there was a sea, at the bottom of which underwater eruptions and powerful outpourings of lavas occurred.
The thickness of the Paleozoic deposits in the Urals is great; it reaches 10-12 km. How could a layer of sediments of such enormous thickness be formed? This can only be explained by the fact that in the region of the sea basin, which was located on the site of the present Urals, as precipitation accumulated, the seabed was lowered.
At the end of the Paleozoic era, the layers that had been deposited over many millions of years were folded into folds and mighty mountain ranges. Particularly significant uplifts occurred in the area of the current mountain strip.
The folds that can be found in many outcrops of the Urals have a rather complex structure. Geologists have long been interested in the conditions under which they form. For the occurrence of bends in thick layers of sandstones and limestones, the rocks had to be in a particularly pliable, plastic state. On the surface of the earth, these rocks, under the conditions familiar to us, are rigid: they are not capable of giving smooth bends and must split under the pressure of the internal forces of the Earth. The plasticity of the rock is acquired in the depths of the earth's crust, so geologists have concluded that the folds, forming mountains, arise in the deep bowels of the Earth.
The formation of the Ural Mountains was accompanied by the introduction of molten, which formed slowly cooling underground foci -. From these cooling hearths, incandescent vapors and hot solutions rose and penetrated into the cracks of the surrounding rocks. The formation of those ore deposits and precious stones for which the Urals are famous. The destruction of the Ural Range, which has been going on for many millions of years, has revealed batholiths frozen in the depths, which now protrude to the surface.
Getting acquainted with the history of the formation of the Urals, south to make sure that in its place during the Paleozoic era there was a region of long-term subsidence, flooded. At the bottom of this sea, there was an accumulation of thick layers of sediments that could be folded into folds. Such areas are called geosynclines. At the end of the Paleozoic (in the Permian period) and at the beginning of the Mesozoic (in the Triassic), major mountain-building processes took place in the Ural geosyncline and high mountain ranges arose.
The emergence of mountains on the site of geosynclines is the basic law of mountain building, which is confirmed by the study of any mountainous country.
After the formation of folds, the intrusion of molten magma and the uplift of mountains, the geosyncline changes its properties. It turns into a more stable, rigid area of the earth's crust, where folds can no longer appear, and under the pressure of mountain-building forces, the rocks split, cracks appear, along which the layers move. This is how faults, grabens and horsts are formed. Areas of the Earth that are not capable of crushing are called platforms. On them, slow uplifts of vast spaces are observed, followed by slow lowerings. These fluctuations are associated with the advances and retreats of the sea.
Splits on the platforms, leading to the formation of normal faults, occur under the influence of pressure coming from geosynclines. In some cases, the movement along the faults reaches a large scale: horsts appear, raised to a height of up to 3-4 km. Fault faults still take place in many mountains on Earth. In the mountains Central Asia, for example, are often associated with rupture of earth layers and the formation of faults.
Horst uplifts lead to the fact that mountain ranges are formed in place of the platforms. These mountains are called blocky(resurrected), as opposed to folded(Urals, Caucasus, Alps), where fold processes play the main role.
Mountains are not eternal, they are “born” and “age”, gradually turning into hills. But how are mountains formed, how do these majestic accumulations of stone giants appear?
As scientists have found out, mountains are formed, or were formed millions of years ago, in four different ways and, according to the method of formation, are folded, vaulted, solid or volcanic.
How are fold mountains formed?
Folded mountains were formed as a result of pressure and compression of the earth's surface during the tectonic movement of the earth's crust. They look like giant folds of rock layers. The Alps are an example of folding mountains.
How are arched mountains formed?
Vaulted mountains are rocks that were raised above the Earth's surface by molten lava as it moved out of the earth's interior. For such mountains, the shape of the vault is characteristic, which is why they are called so.
How are whole mountains formed?
Whole mountains were formed when entire sections of the earth's surface were raised or lowered during tectonic movement. Whole mountain ranges (for example, the Sierra Nevada) are the result of faults or, conversely, failures of the earth's crust.
How are volcanic mountains formed?
Volcanic mountains are extinct or (for example, Vesuvius or Fujiyama). They consist of lava, ash ejected during volcanic eruptions and have a conical shape.
These are the main ways of forming mountains, but many mountains appeared as a result of their combination during the tectonic movement of the layers of the earth's crust.
First, let's see what is currently known about the structure and development of mountain systems. Mountains have some peculiarities. The first of these is the staging of development. There are usually three stages.
First - period of subsidence and accumulation of thick sedimentary strata.
Second - stage of formation and formation of mountains.
And finally, the third - the stage of aging and destruction of mountains. Such a sequence of the process of mountain building was noticed even during the formation of the doctrine of geosynclines ( late XIX- the beginning of the 20th century).
However, in our opinion, in the doctrine of the development of mountains, a very significant, albeit outwardly hardly noticeable, stage was omitted, which can be conditionally called prageosynclinal, i.e., preceding the appearance of the geosynclinal basin. It was revealed only now, at the stage of widespread use of deep drilling and seismic methods, which made it possible to better understand the structure of mountains and foothills. The presence of this stage is confirmed, for example, by analysis of the geological structure of the northwestern part of the Appalachians and the Swiss Jura. So, on the northwestern margin of the Appalachians, the folds are located directly on the Precambrian basement ( left side drawing). Moreover, the lower layers lie almost horizontally, and if they did not gradually sink to the southeast into the depths of the Appalachian Mountains, then it would be impossible to assume their connection with the Appalachian fold zone. But such a connection exists, and, obviously, weakly disturbed strata underlying the sedimentary rocks characterize some preliminary phase of the formation of the geosyncline. This stage differs from the next one, the actual geosynclinal one, by a calm, gradual subsidence. Thus, the full cycle of mountain development does not consist of three, but of four stages.
The second feature of mountains is the complexity and diversity of structures within a single mountain system.
Structural variegation is often so great that it seems that neighboring areas are not part of a single mountain structure.
Finally, the third feature of mountains is that within their limits the earth's crust is thickened. With an average thickness on the continents of 30-35 km in young folded systems - the Pamirs, the Caucasus, the Alps, the Cordillera, the Hades - it reaches 50-62 km. And since the mountains do not rise above 7-8 km above sea level, the crust within them is, as it were, pressed into the peridotite shell, forming “mountain roots”.
According to the geophysicist I.P. Kosmiiskaya, the thickening of the crust in young mountain ranges occurs due to a more powerful granite layer.
Indeed, in terms of the speed of propagation of seismic waves, this part is quite close to granites. But is it granite?
As already mentioned, the thickness of the sedimentary strata crumpled into folds in mountainous areas reaches twenty or more kilometers, in any case, it is almost always at least fifteen. This is probably just the value that corresponds to the thickness of the granitic part of the crust that is absent here, and sedimentary rocks in the mountainous regions apparently lie directly on the basalts. This is confirmed by geophysical data on typical geosynclinal depressions - the Black Sea and the Caspian.
Do all mountains have roots? No, this belongs only to young fold systems, therefore, at the stage of subsidence and in the era of mountain aging, there are no roots. Consequently, only when the mountains rise upwards, and their bases sink down into the peridotite zone, do the roots of the mountains appear.
These are the facts. They demand an explanation.
Let's look at the aforementioned stages in the development of mountain systems, how these facts are linked with the idea of the expansion of the Earth. The first stage is prageosynclinal. It is characterized by the accumulation, sometimes very significant, of sedimentary strata lying horizontally, and the complete absence of volcanism. Consequently, there is still no direct connection with the deep layers of the Earth. The accumulation of sediments is obviously caused by extension (but not rupture) and deflection of the granite layer of the earth's crust.
The second stage, actually geosynclinal, is the time of prolonged subsidence and accumulation of thick sedimentary strata, accompanied by intense outpourings of lavas and active volcanic activity. The stage under consideration is due to further stretching and rupture of the granite part of the crust, which leads to direct contact of sedimentary rocks with deep crystalline ones. From the basalt strata, now overlain by crushed rocks of the granite layer and relatively loose sedimentary rocks, magma is easily released, literally stuffed with expanded (due to pressure reduction) gases.
The third stage - the stage of formation of folds and mountains - can also be explained by accepting the expansion hypothesis, although it would seem that this is where its Achilles' heel is located. After all, it is usually believed that the folds are the result of lateral pressure or pressure coming from below. And suddenly - the denial of both.
Why, in our opinion, is it impossible to consider lateral pressure as the main factor leading to the formation of folds? Because it cannot be transmitted over a distance equal to many hundreds of kilometers, and will be extinguished already a few kilometers from the pressing object.
In addition, the neighborhood of diverse sites found in some mountainous regions can serve as confirmation that there were probably no single mountain-building movements that formed the entire mountain system at once, and each site arose on its own, individually.
Then, perhaps, the mechanism of "vertically moving pistons" worked here? It is unlikely, since simultaneously with the rise of the tops of the mountains to transcendental heights, their roots penetrated downward, i.e., the movement simultaneously went in opposite directions.
So, we can assume that neither horizontal compression nor vertical uplift could lead to the formation of mountains. Therefore, one thing remains: it is likely that mountains are formed as a result of deconsolidation of crystalline and sedimentary rocks that make up the upper part of the earth's crust.
Is it not surprising that now we have to return to the conclusion made back in 1899 by Datton, who pointed out that one of the causes of mountain building is "... the gradual expansion or decrease in the density of underground magmas."
I. V. Kirillov also came to the idea of "swelling" as a possible cause of the formation of mountains. His idea formed the basis of our development.
Under what conditions and how, from our point of view, does the “swelling process” take place? It should go especially vigorously at the base of the mountains, since magmas saturated with expanded gases “act” there. But "swelling" alone is not enough for mountains to appear, since the rocks "swell" first under conditions of stretching of the crust and, therefore, cannot rise up, all the while spreading to the sides. And only at the moments of suspension of tension, when the rocks that have increased in volume no longer have an exit to the sides, they rise up with force and are pressed down into the plastic basalt mass, forming mountains and their roots.
Since the history of the Earth is dominated by extension, and its temporary suspensions are not very long, the epochs of mountain building turn out to be much shorter than the periods of formation of geosynclinal troughs preceding them. No wonder the epochs of mountain building are called revolutionary stages in the development of the Earth, during which its face is dramatically transformed.
Finally, the last stage is the stage of mountain aging. This process is also explained in terms of the expansion hypothesis.
Aging is a slowdown of some active processes, due to which destruction begins to prevail over creation. This is what happens in this case as well. We have seen that the intrusion of magmas saturated with expanded gases is the result of an imbalance, and as soon as it is restored - and this happens at a time when magmas are degassed and sedimentary rocks are granitized - the very process of growth of mountains and their roots dies out and begins destruction occurring under the action of water, weathering and other factors.
The tops of the mountains disappear, and their roots are pulled up. After several stages of folding, the geosynclinal zones turn into young platform areas.
Hello friends! So, today I have prepared for you material on the formation of mountains, as well as a table of the highest mountains in the world by continent, which you can see at the end of the article. Well, let's find out what mountains are, how they form and how to distinguish them...
There were times when mountains were considered mysterious and dangerous place. However, many of the mysteries associated with the appearance of mountains have been unraveled in the past two decades thanks to a revolutionary theory - lithospheric plate tectonics.
Mountains are elevated areas of the earth's surface that rise steeply above the surrounding area.
Peaks in the mountains, unlike plateaus, occupy a small area. Mountains can be classified according to different criteria:
- Geographical position and age, taking into account their morphology;
- Features of the structure, taking into account the geological structure.
Mountains in the first case are divided into mountain systems, cordillera, single mountains, groups, chains, ridges.
The name Cordelier comes from the Spanish word for chain. Cordeliers include groups of mountains, ranges and mountain systems of different ages.
In western North America, the Cordelier region includes the Coast Ranges, the Sierra Nevada, the Cascade Mountains, the Rocky Mountains, and many smaller ranges between the Sierra Nevada in Nevada and Utah and the Rocky Mountains.
To the Cordeliers Central Asia(you can learn more about this part of the world) include, for example, the Tien Shan, Kanlun and the Himalayas. Mountain systems are made up of groups of mountains and ranges that are similar in origin and age (the Appalachians, for example).
The ridges consist of mountains that stretch in a narrow long strip. Solitary mountains, usually of volcanic origin, are found in many parts of the world.
Second classification The mountains are compiled taking into account the endogenous processes of relief formation.
Volcanic mountains.
Volcanic cones are widespread in almost all regions of the globe.
They are formed by accumulations of rock fragments and lava erupted through vents by forces that operate deep in the bowels of the Earth.
Illustrative examples of volcanic cones are Shasta in California, Fujiyama in Japan, Mayon in the Philippines, Popocatepetl in Mexico.
Ash cones have a similar structure, but they are mostly volcanic cinders and are not as tall. There are such cones in northeastern New Mexico and near Lassen Peak.
During repeated eruptions of lava, shield volcanoes form (more about volcanoes). They are kind of not as tall and not as symmetrical as volcanic cones.
There are many shield volcanoes in the Aleutian and Hawaiian Islands. The chains of volcanoes meet in long narrow bands.
Where the plates that lie at the ridges stretching along the bottom of the oceans diverge, magma, trying to fill the crevice, rises up, eventually forming a new crystalline rock.
Sometimes magma piles up on the seabed - thus, underwater volcanoes appear, and their peaks rise above the surface of the water as islands.
If two plates collide, one of them raises the second, and that, drawn deep into the oceanic basin, melts to the state of magma, part of which is pushed to the surface, creating chains of islands of volcanic origin: for example, Indonesia, Japan, the Philippines arose like this.
The most popular chain of such islands is these are the Hawaiian Islands, 1600 km long. These islands were formed as a result of the northwestward movement of the Pacific Plate over a hot spot in the earth's crust. hot spot in the earth's crust this is the place where a hot mantle flow rises to the surface, which melts the oceanic crust moving above it.
If we count from the surface of the ocean, where the depths are about 5500 m, then some of the peaks Hawaiian Islands will be among the highest mountains in the world.
Fold mountains.
Most experts today believe that the cause of folding is the pressure that occurs when the tectonic plates drift.
The plates on which the continents rest move only a few centimeters a year, but their convergence causes the rocks on the edges of these plates and the layers of sediment on the ocean floor that separate the continents to gradually rise up the crests of mountain ranges.
Heat and pressure are formed during the movement of the plates, and under their influence, some layers of the rock are deformed, lose their strength and, like plastic, bend into giant folds, while others, stronger or not so heated, break and often tear off from their base.
At the stage of mountain building, heat also leads to the appearance of magma near the layer that underlies the continental crust.(more detailed information about the earth's crust).
Huge patches of magma rise and solidify to form the granite core of the folded mountains.
Evidence of past clashes of continents - these are old folded mountains that have stopped growing for a long time, but have not yet collapsed.
For example, in the east of Greenland, in the northeast of North America, in Sweden, in Norway, in the west of Scotland and Ireland, they appeared at a time when Europe (more about this part of the world) and North America(more about this continent), came together and became one huge continent.
This huge mountain range, due to the formation Atlantic Ocean, broke later, about 100 million years ago.
At first, many large mountain systems were folded, but in the course of further development their structure became much more complicated.
Zones of initial folding are limited by geosynclinal belts - huge troughs in which sediments accumulated, mainly in shallow oceanic formations.
Often folds are visible in mountainous areas on exposed cliffs, but not only there. Synclines (troughs) and anticlines (saddles) are the simplest of folds. Some folds are overturned (lying down).
Others are displaced in relation to their base so that the upper parts of the folds are put forward - sometimes for several kilometers, and they are called integuments.
Blocky mountains.
Many large mountain ranges were formed as a result of tectonic uplift, which occurred along the faults of the earth's crust.
The Sierra Nevada Mountains in California it is a huge horst about 640 km long and 80 to 120 km wide.
The eastern edge of this horst was raised the highest, where the height of Mount Whitney reaches 418 m above sea level.
To a large extent, the modern appearance of the Appalachians was formed due to several processes: the primary folded mountains were subjected to denudation and erosion, and then uplifted along faults.
In the Great Basin, between the Sierra Nevada mountains to the west and the Rocky Mountains to the east, there is a series of blocky mountains.
Long narrow valleys lie between the ridges, they are partially filled with sediments brought from adjacent blocky mountains.
Domed mountains.
In many areas, land areas that have undergone tectonic uplift, under the influence of erosion processes, have taken on a mountainous image.
In those areas where the uplift took place on a relatively small area and was of a domed nature, dome-shaped mountains formed. The Black Hills are a striking example of such mountains, which are about 160 km across.
This area has undergone dome uplift and much of the sedimentary cover has been removed by further denudation and erosion.
The central core, as a result, was exposed. It consists of metamorphic and igneous rocks. It is surrounded by ridges, which are composed of more resistant sedimentary rocks.
Remaining plateaus.
Due to the action of erosion-denudation processes, a mountain landscape is formed on the site of any elevated territory. Its appearance depends on its initial height.
With the destruction of a high plateau, like Colorado, for example, a strongly dissected mountainous relief was formed.
The Colorado Plateau hundreds of kilometers wide was raised to a height of about 3000 m. Erosion-denudation processes have not yet managed to completely transform it into a mountainous landscape, but within some large canyons, for example grand canyon R. Colorado, mountains a few hundred meters high arose.
These are eroded remnants that have not yet been denuded. With the further development of erosion processes, the plateau will acquire an increasingly pronounced mountainous appearance.
In the absence of re-elevation, any territory will eventually level out and turn into a plain.
Erosion.
Already at the time when the mountains grow, the process of their destruction begins. In the mountains, erosion is especially strong, because the slopes of the mountains are steep and the effect of gravity is most powerful.
As a result of this, blocks that collapse from frost roll down and are carried away by glaciers or turbulent waters of mountain streams rushing through deep gorges.
It is all these forces of nature, together with plate tectonics, that form the impressive mountain landscape.
Table of the highest mountains in the world by continent
|
Mountain peaks |
Absolute height, m |
|
Europe |
|
| Elbrus, Russia |
5642 |
| Dikhtau, Russia |
5203 |
| Kazbek, Russia - Georgia |
5033 |
| Mont Blanc, France |
4807 |
| Dufour, Switzerland - Italy |
4634 |
| Weishorn, Switzerland |
4506 |
| Matterhorn, Switzerland |
4478 |
| Bazarduzu, Russia - Azerbaijan |
4466 |
| Finsterarhorn, Switzerland |
4274 |
| Jungfrau, Switzerland |
4158 |
| Dombay-Ulgen (Dombay-Elgen), Russia - Georgia |
4046 |
|
Asia |
|
| Chomolungma (Everest), China - Nepal |
8848 |
| Chogori (K-2, Godui-Austen), India - China |
8611 |
| Kanchenjunga, Nepal - China |
8598 |
| Lhotse, Nepal - China |
8501 |
| Makalu, China - Nepal |
8481 |
| Dhaulagari, Nepal |
8172 |
| Manaslu, Nepal |
8156 |
| Chopu, China |
8153 |
| Nanga Parbat, Kashmir |
8126 |
| Annapurna, Nepal |
8078 |
| Gasherbrum, Kashmir |
8068 |
| Shishabangma, China |
8012 |
| Nandadevi, India |
7817 |
| Rakaposhi, Kashmir |
7788 |
| Kamet, India |
7756 |
| Namchabarw, China |
7756 |
| Gurla Mandhata, China |
7728 |
| Ulugmustag, China |
7723 |
| Kongur, China |
7719 |
| Tarichmir, Pakistan |
7690 |
| Gongashan (Minyak-Gankar), China |
7556 |
| Kula Kangri, China - Bhutan |
7554 |
| Muztagata, China |
7546 |
| Communism Peak, Tajikistan |
7495 |
| Pobeda Peak, Kyrgyzstan - China |
7439 |
| Jomolhari, Bhutan |
7314 |
| Lenin Peak, Tajikistan - Kyrgyzstan |
7134 |
| Peak Korzhenevskaya, Tajikistan |
7105 |
| Peak Khan Tengri, Kyrgyzstan |
6995 |
| Kangrinboche (Kailash), China |
6714 |
| Khakaborazi, Myanmar |
5881 |
| Damavend, Iran |
5604 |
| Bogdo-Ula, China |
5445 |
| Ararat, Turkey |
5137 |
| Jaya, Indonesia |
5030 |
| Mandala, Indonesia |
4760 |
| Klyuchevskaya Sopka, Russia |
4750 |
| Trikora, Indonesia |
4750 |
| Ushba, Georgia |
4695 |
| Belukha, Russia |
4506 |
| Munkhe-Khairkhan-Uul, Mongolia |
4362 |
|
Africa |
|
| Kilimanjaro, Tanzania |
5895 |
| Kenya, Kenya |
5199 |
| Rwenzori, Congo (DRC) - Uganda |
5109 |
| Ras Dashen, Ethiopia |
4620 |
| Elgon, Kenya-Uganda |
4321 |
| Toubkal, Morocco |
4165 |
| Cameroon, Cameroon |
4100 |
|
Australia and Oceania |
|
| Wilhelm, Papua New Guinea |
4509 |
| Giluwe, Papua New Guinea |
4368 |
| Mauna Kea, about. Hawaii |
4205 |
| Mauna Loa, about. Hawaii |
4169 |
| Victoria, Papua New Guinea |
4035 |
| Capella, Papua New Guinea |
3993 |
| Alyuert Edward, papua new Guinea |
3990 |
| Kosciuszko, Australia |
2228 |
|
North America |
|
| McKinley, Alaska |
6194 |
| Logan, Canada |
5959 |
| Orizaba, Mexico |
5610 |
| Elijah, Alaska - Canada |
5489 |
| Popocatepetl, Mexico |
5452 |
| Foraker, Alaska |
5304 |
| Iztaxihuatl, Mexico |
5286 |
| Lucaynia, Canada |
5226 |
| Bona, Alaska |
5005 |
| Blackburn, Alaska |
4996 |
| Sanford, Alaska |
4949 |
| Wood, Canada |
4842 |
| Vancouver, Alaska |
4785 |
| Churchill, Alaska |
4766 |
| Fereeter, Alaska |
4663 |
| Bear, Alaska |
4520 |
| Hunter, Alaska |
4444 |
| Whitney, California |
4418 |
| Elbert, Colorado |
4399 |
| Massive, Colorado |
4396 |
| Harvard, Colorado |
4395 |
| Rainier, Washington |
4392 |
| Nevado de Toluca, Mexico |
4392 |
| Williamson, California |
4381 |
| Blanca Peak, Colorado |
4372 |
| La Plata, Colorado |
4370 |
| Ancompagre Peak, Colorado |
4361 |
| Creston Peak, Colorado |
4357 |
| Lincoln, Colorado |
4354 |
| Grace Peak, Colorado |
4349 |
| Antero, Colorado |
4349 |
| Evans, Colorado |
4348 |
| Longs Peak, Colorado |
4345 |
| White Mountain Peak, California |
4342 |
| North Palisade, California |
4341 |
| Wrangel, Alaska |
4317 |
| Shasta, California |
4317 |
| Sill, California |
4317 |
| Pikes Peak, Colorado |
4301 |
| Russell, California |
4293 |
| Split Mountain, California |
4285 |
| Middle Palisade, California |
4279 |
|
South America |
|
| Aconcagua, Argentina |
6959 |
| Ojos del Salado, Argentina |
6893 |
| Bonet, Argentina |
6872 |
| Bonete Chico, Argentina |
6850 |
| Mercedario, Argentina |
6770 |
| Huascaran, Peru |
6746 |
| Llullaillaco, Argentina - Chile |
6739 |
| Erupaja, Peru |
6634 |
| Galan, Argentina |
6600 |
| Tupungato, Argentina - Chile |
6570 |
| Sajama, Bolivia |
6542 |
| Coropuna, Peru |
6425 |
| Illampu, Bolivia |
6421 |
| Illimani, Bolivia |
6322 |
| Las Tortolas, Argentina - Chile |
6320 |
| Chimborazo, Ecuador |
6310 |
| Belgrano, Argentina |
6250 |
| Toroni, Bolivia |
5982 |
| Tutupaca, Chile |
5980 |
| San Pedro, Chile |
5974 |
|
Antarctica |
|
| Vinson array |
5140 |
| Kirkpatrick |
4528 |
| markham |
4351 |
| Jackson |
4191 |
| Sidley |
4181 |
| Minto |
4163 |
| Wertherkaka |
3630 |
Well, dear friends, now we have found out the process of formation of mountains, learned their main types and characteristics of each of them, and also examined the most high mountains world in the table.
The question of how mountains were formed occupied people already in ancient times, but they could not answer it, since they knew too little the composition and structure of the earth's crust. Therefore, they thought that the masses supporting the clouds were created by gods or spirits. People believed that the gods built mountains in order to support the vault of heaven. We have already talked about Mount Olympus, on which, according to legend, the gods lived ancient greece. People also thought that mountains were not fixed in one place and that the gods could pick them up and throw them at each other during their battles.
The inhabitants of Kamchatka have the following legend about Mount Shiveluch. This mountain is a volcano; it stands completely apart from other volcanoes of Kamchatka. Local Kamchadal residents believe that once this volcano was located among other volcanoes on the site of the current Kronotsky Lake. But the groundhogs, which were found in abundance in this area, disturbed the volcano so much by digging their holes on its slopes that he finally decided to leave them. The volcano broke away from the ground, leaving behind a large depression, in which water later accumulated and a lake formed. The volcano flew north, but during the flight it caught on the top of a neighboring mountain and broke it off, and descending to the ground, squeezed out depressions for two more lakes before choosing a place for itself 220 kilometers from the old one. In this new place, the volcano strengthened forever.
Many peoples have similar legends about the formation of mountains. They certainly have nothing to do with the actual formation of mountains.
2. MOUNTAINS - WRINKLES OF THE COOLING EARTH
Many people compare mountains on Earth to the wrinkles that form on the skin of a drying apple or potato. It is sometimes said that the mountains on Earth arose in exactly the same way as these wrinkles.
It's not quite right. The earth does not shrink, but decreases in its volume, because it is constantly cooling, cooling down. This cooling began even when the substance that makes up the Earth began to condense into a ball of hot gases, and then into a fiery-liquid ball; it continued, albeit more slowly, after the formation of the solid earth's crust, and is also happening at the present time. Volcanoes, ejecting hot gases and fiery liquid lava, as well as forming numerous hot springs, constantly bring a lot of heat from the earth's interior to the surface, and this heat is lost to the Earth irretrievably; the heat that the sun's rays give the Earth penetrates only a few meters deep into the earth's crust. Thus, the Earth loses more heat than it receives, and therefore slowly cools.
Volcanic eruptions, hot springs, as well as observations in boreholes and deep mines show that with the deepening into the earth's crust, the temperature of the rocks rises markedly. This proves that a lot of heat has been preserved in the bowels of the Earth, and this heat continues to be consumed. But, as is known, any body during cooling decreases in its volume; the earth's core (the inner part of the globe) is also decreasing. Therefore, the earth's crust, adapting to the shrinking core, must wrinkle, its layers form folds-wrinkles, which represent mountain ranges. If we recall that the diameter of the globe is approximately 13 thousand kilometers, and the highest mountains reach only 7–8 kilometers, then they are insignificant wrinkles compared to the Earth, much smaller than the wrinkles of the peel of a dried apple.
This explanation for the formation of mountains is still very common among scientists; it is, in general, correct, but not sufficient. The formation of mountains is more complex than has just been described. It will become clear to us if we get to know more closely the structure of these "wrinkles" or, as scientists call them, the folds of the earth's crust.
3. WHAT DO THE MOUNTAIN FOLDS TELL?
Folds can be very well seen and studied on the slopes of mountains and hills, in gorges, in steep cliffs of the banks of rivers, lakes and seas - in general, almost everywhere where layers of sedimentary rocks protrude. It is precisely such rocks, consisting of separate regular layers lying on top of each other like the leaves of a book, that well show the folded formation of mountains. The layers were originally formed in the water at the bottom of some reservoir and, during their formation, lay flat - horizontally or with a very gentle slope in one direction or another. But in the mountains we see that these layers are inclined steeply or stand even vertically - "set on their heads." It means that some powerful force lifted them, moved them from their place.
Rice. 8. Mountain folds.
Let's follow the same rock layer in a fold (Fig. 8). We will see that it rises, gradually bends, forming an arch, then falls down, then rises again. And all the other layers lying under it and above it repeat the same movement. Sometimes such a fold is completely isolated, lonely, but usually one fold is followed by others. The shapes of the folds are different - sometimes flat (Fig. 9, a), then steep (Fig. 9, b), sometimes with smooth bends, sometimes with fractures at an angle (Fig. 9, v). There are folds in which the inflection is turned neither up nor down, but sideways; such folds are called recumbent (Fig. 9, G). Sometimes very complex folding is obtained, which can also often be seen in the mountains (Fig. 9, d); it shows that in this place the earth's crust was compressed, wrinkled very strongly, and the folds were bent, forming mountains.
Rice. 9. Various forms of folds: a - flat; b - cool; c - with a sharp fracture; g - recumbent; d is complex.
The reader, who has never been in the mountains and who has not seen these folds with his own eyes, will say with disbelief: this cannot be! Layers of such hard rocks as sandstones, limestones, shales are not paper, not cloth, not leather, which can be bent in any way. Scientists used to think so too, and therefore believed that the folds were formed at a time when the rocks were still soft and consisted of sand, clay, and silt. But the study of the mountains showed that the rocks did bend in a solid state. This can be seen from the fact that the layers suffered greatly during bending - they are torn apart by small cracks, in some places even crushed, and parts of the torn layers are often moved away from each other (Fig. 10). Such broken folds can be seen in the mountains; shifts sometimes reach a huge value.
Rice. 10. Shear formation due to fold rupture. The black straight line shows in which direction the shift occurred.
The bends of solid rocks are explained as follows. The layers now raised high in the mountains formerly lay at great depths and were under the pressure of all the layers lying above. And under strong pressure, even solid bodies can change their shape. So, for example, lead under strong pressure can pass through a narrow hole in a jet, like water, and thick sheets of iron, steel, copper bend like a sheet of paper. Glass and ice are very fragile bodies, but they can also be bent without breaking if you press on them very slowly and gradually.
In the depths of the earth's crust, rocks could bend very strongly, tearing only slightly; of course, these bends happened very slowly. But when the pressure force was already too great, then the fold was torn in one place or another and its parts moved towards each other, as we saw in Figure 10.
4. Faults of the Earth's crust
The ruptures of rock layers occurred not only from the pressure of the upper layers on the lower ones. In addition to these pressure forces, which crushed layered rocks into folds, other forces acted, lifting molten masses from the depths of the earth from the bottom upwards, to the surface of the Earth. They tore the earth's crust with large cracks, along which one side went up or the other went down. Such breaks and movements of the earth's crust are called faults (Fig. 11); they can often be seen both in the mountains and in the mines, both near folds, and in such areas where there are no folds. The faults are well known to both the miner and the miner from bitter experience. Encountering a crack along which a displacement has occurred, he sees that a layer of coal or a vein with ore behind the crack suddenly disappears, as if cut off, and the face rests on empty rock. The disappeared continuation of the layer or vein has to be looked for at the top, bottom or side.
Rice. 11. Reset. Layers that make up a single whole before the break are shaded in the same way.
When dumping, sometimes entire sections, huge blocks of the earth's crust move; they also form mountains, but these mountains are of a different kind than those produced by the formation of folds.
The ruptures of the earth's crust with deep cracks created convenient ways for the molten masses located at a depth to climb up; along the cracks of the gaps, an easier road was prepared for them. Molten masses used this road and penetrated the surface of the Earth, creating volcanoes, or stopped at some depth, where they solidified, forming massifs of deep rocks. That is why along the large cracks that cut through the earth's crust, we especially often see extinct and active volcanoes. Such areas where the earth's crust is strongly cut by cracks and where there are many volcanoes, we see along the coast Pacific Ocean, - there stretch long chain fire-breathing mountains.
5. WHAT FORCES FORMED THE MOUNTAINS?
Now we know how the mountains were formed, how they rose up. It remains to answer the question - what forces created these irregularities on the surface of the continents?
There are several scientific assumptions (or, as scientists call them, hypotheses) about the reasons for the formation of mountains. We will not consider all these hypotheses here - this would require a lot of time. We will confine ourselves to presenting one hypothesis proposed by the Soviet scientist Usov and the American geologist Vecher. This hypothesis is called "pulsating" from the word "pulsate", that is, to act in jolts. It consists of the following.
It is well known that all bodies expand when heated and contract when cooled. This also applies to the particles of substances that make up the Earth.
Because Earth cools all the time, then its particles are compressed, attracted to each other. This compression causes the particles to move faster; scientists have established that such an increase in movement leads to an increase in temperature, to heating of bodies. And this heating causes the expansion of bodies and the repulsion of particles from each other. Thus, in the depths of the Earth, from the beginning of its formation to the present, there has been a struggle between the forces of attraction and repulsion of particles. As a result of this struggle, the solid earth's crust oscillates, and all those irregularities that we spoke about are created on its surface. According to the Usov-Becher theory, compression and expansion do not occur simultaneously, but alternately, in the form of shocks - the earth's interior "pulsates". A sharp contraction is usually followed by a more or less sharp expansion. Folding of rocks is caused by their compression in geosynclines, and the uplift of folded strata from geosynclines and their transformation into mountain ranges occurs during expansion, which has replaced compression.
In the earth's crust, periods (times) of compression are expressed in different ways in its different parts: in geosynclines, where thick strata of sedimentary rocks have accumulated, compression creates strong and complex folding; in stable places, separate blocks move out along rupture cracks. Periods of stretching of the earth's crust during the expansion of the Earth's core also cause various consequences: stable places are cut by new cracks of ruptures, old cracks expand, and volcanic rocks are poured onto the surface through both; individual blocks and squares rise. In geosynclines, strata of sedimentary rocks, strongly compressed during the period of compression, bulge upward and form mountain ranges, and molten masses penetrate these strata from the depths through cracks and form massifs and veins of deep rocks, partly also reaching the surface and creating volcanoes.
The study of the structure of mountains in different countries showed that periods of strong contraction and the formation of folds occur everywhere on the Earth almost simultaneously and consist of several separate shocks separated from each other by times of comparative rest. A lot of time elapses from one push to the next.
The last strong movements on Earth occurred, as scientists have established, more than a million years ago.
At present, the Earth is experiencing a quieter period, but accurate observations have shown that weak movements of the earth's crust are still ongoing. By measuring the level of the oceans, scientists have found that in some places the shores are rising, in others they are lowering.
On the slopes of river valleys, so-called terraces are formed, i.e. steps, which are formed due to the uplift of the terrain, which caused an increase in the slope of the river channel and therefore an increase in the eroding power of the water and a new incision of the channel into the old deposits of the same river or into the root bottom of the valley. Finally, strong earthquakes occurring in different countries from time to time are undoubtedly caused by a sudden displacement of strata in the depths of the crust, and at times repeated eruptions of the same volcano prove that weak movements of the earth's crust are still taking place.
On the site of internal and coastal geosynclines, mountains arise, which join the continents and increase their size; this is repeated in every period of expansion, so that during such past periods the continents gradually grew larger.
On the other side, large areas the earth's crust can sink below ocean level and be flooded by the sea; near mountain range, rising from the geosyncline, a new depression is formed, which can also be flooded with water. The sea advances on land and its retreat occurs when the earth's crust rises and geosynclines turn into mountain structures. So there is a constant struggle between land and water.
Research has shown that in general area continents has increased significantly against the original.
