What are fold mountains: examples. Classification of mountains. Mountains, differences in mountains by height and origin. Main forms of mountainous landforms

Mountain systems occupy about forty percent of the surface of our planet: they can be seen on every continent, on many islands and on the ocean floor. The fewest ranges are found on the Australian continent, and almost all the mountain ranges of Antarctica are reliably hidden under ice.

Parts are called mountains earth's crust, which, as a result of the movement of tectonic plates, volcanic eruptions or other processes occurring within the planet, rose to a significant height and began to rise above the plains. The height of some hills is small and amounts to about three hundred meters, others rise more than eight thousand meters above. The type of mountains is extremely diverse: it can be a single peak, or it can be a long mountain range, which includes hundreds and even thousands of cones.

Considering that the structure of the mountains is ten percent sedimentary, and ninety percent igneous and metamorphic rocks (appearing as a result of changes in the structure of sedimentary and volcanic rocks), geologists often discover mineral deposits inside them and under the mountain.

The mountain relief consists of several parts:

Mountain (hill) – low or high mountain cone-shaped, consisting of a top, slopes and a bottom (the place where the slopes merge with the surrounding area);
Ridges are strongly elongated mountain heights, the slopes of which, on the one hand, are often gentle, and on the other, steep. They are also watersheds because they direct river water flowing downhill from different sides of the slopes in opposite directions. For example, the Rocky Mountains extend from the north to southeast direction, while their length is about five thousand kilometers, thanks to which the Rocky Mountains are a watershed between the basins of the Pacific and Atlantic oceans;
A saddle is a depression of relief between two hills located near each other, usually the beginning of two valleys that go downhill in different directions;
A hollow is an open, slightly inclined, downhill depression in the relief, which below, when the slopes merge, forms a drainage line;
Basin - located below sea level, a cone-shaped depression, which is characterized by a bottom, slopes and an edge line - the place where the slopes meet the surface.

Formation theory

Throughout the history of their development, people have put forward a variety of theories about how exactly the mountains of the world were formed. At first these were myths, legends and tales, then the versions began to be more substantiated. For example, it has been suggested that mountain systems arose due to the movement of matter under the ocean floor, causing the arching of its surface, which causes the heaving of the earth's crust along the margins of the ocean.

This hypothesis did not explain in any way the presence of mountain systems inside the continent. Then they considered the version that the Earth is constantly decreasing in volume, and this happens in leaps and bounds and leads to deformation of the surface, where folds are formed, some of which rise above the surface, and the other goes downhill.

Later, the idea emerged that the mountain system was formed during continental drift. The idea was not bad, but it did not explain the reason for the movement of the continents, so it was forgotten. Instead, another hypothesis arose, suggesting that there are currents inside the Earth that cause the rise and fall (going downhill) of the earth's crust, affecting the topography of the planet. Despite the fact that many people liked the idea, no scientific evidence was found to support it.

The modern hypothesis of the formation of mountains arose in the middle of the last century, when it was proven that during the collision of which a thinner plate goes under the neighboring one, forming hills on the earth's surface. This theory was combined with previous versions, it explained a lot and was accepted as the main one.

Age of the mountains

Based on the theory of the movement of tectonic plates and soil analyses, it was found that each mountain system was formed at one time. The age of young ranges ranges from 50 to 80 million years, while old mountain systems appeared more than a hundred million years ago (for comparison, the age of our planet is about four and a half billion years).

Young mountain ranges (Rocky Mountains, Himalayas) are interesting because their internal processes are still developing. For example, due to the constant collision of the Indian and Asian plates, the high mountains of the Himalayas grow by five centimeters per year. This process is always accompanied by earthquakes, and in some cases – volcanic eruptions. A young, growing mountain system is easily recognizable by its sharply defined relief, consisting of alternating peaks and protrusions, the sharp shape of the peaks, and the presence of very steep and high slopes that complicate both the ascent and descent from the mountain.

The ancient mountain system differs from the younger one in that all processes inside it have long ceased, while external processes that cause erosion continue to affect the surface of the Earth. Interesting fact: geologists have discovered more than one area on the plains where there was previously a mountain system, from which only roots remained, securely hidden under a thick layer of sedimentary rocks. The most ancient hills of the Earth were recognized as the remains of mountains that are located in the Hudson Bay area: they appeared almost simultaneously with our planet.

As for the ancient mountains, which time has not erased from the face of the Earth (for example, the Ural or Scandinavian), they can be recognized primarily by their height, not exceeding one and a half thousand meters, gentle slopes, and also by severe erosion. If in the young mountains water flows flow in narrow gorges, then the rivers of the old mountain flow along a well-defined wide river valley.

It is not uncommon for older mountain ranges to include younger formations. For example, the Rocky Mountains, which appeared as a result of a tectonic shift from 80 to 50 million years ago, are a young part of the Western Cordillera, which began to form more than 120 million years ago. It should be noted that the Rocky Mountains are still growing, so earthquakes and post-volcanic phenomena are common in the region where they are located.

Types of mountains

The answer to the question of what kinds of mountains there are is not as simple as it seems: mountain ranges differ not only in age, but also in structure, origin, shape, location, height:

In terms of altitude, low mountains are characterized by heights of up to 800 meters, middle mountains – up to 3 thousand meters and high mountains – more than 3 thousand meters. The height of mountains in some cases can reach incredible proportions. For example, which for a long period was listed in reference books as the highest mountain in the world, is almost nine kilometers. Recently this primacy was called into question when, big mountain, exceeding the size of Chomolungma: the height of the inactive Mauna Kea volcano from its base to its summit exceeds ten kilometers.
By origin - volcanic, tectonic or erosional (erosion of plains by strong river flows, for example, canyons and mesas consisting of limestone, basalt, sandstone).
At the top, a young high mountain usually has a peak-shaped, pointed shape. The top of the mountain can have a plateau-shaped, dome-shaped or rounded shape, which is typical both for old, heavily destroyed volcanoes and for areas where a large mountain has arisen as a result of the collision of plates.

Zoning

If the hill itself is not high, then the nature of the mountain at its base and at the top is not particularly different. True, this largely depends on which altitudinal group it belongs to. For example, the characteristic of continental-type mountains implies a complete absence of forests.

But when describing the low and middle elevations of the coastal type, one cannot fail to mention the presence of a forest landscape and meadows. If we are talking about a mountain higher than three thousand meters, it is worth considering: in order to climb to its top, you need to overcome absolutely all the belts of our planet. Therefore, the weather in the mountains differs significantly from the climate of the adjacent plains.

This is explained by the fact that the temperature drops by six degrees with each kilometer traveled. In addition, atmospheric pressure decreases, the level of solar radiation increases and the amount of precipitation changes. Accordingly, such weather in the mountains also affects nature.

Exactly how many zones a high mountain will have depends largely on what climatic zone it is in (mountain ranges near the equator have the largest number of zonal zones). It is also important at what height these zones will be located, how the slopes are located: on the sunny side they are usually lower. Geologists divide altitudinal zones into several parts.

Nival altitude belt

Only a high mountain can boast of having a nival belt: in the tropics it begins at an altitude exceeding 6.5 km above sea level. m., the further north it is, the lower it is located (ascent and descent from the mountain is quite difficult and often fraught with death).

This zone is characterized by the presence of glaciers and eternal snow (the Rocky Mountains or the Himalayas, which include the highest mountain in the world, Everest), while the surface not covered with snow is subject to severe erosion, primarily weathering. The vegetation here is extremely sparse - lichens and a few herbs. There are also few animals: sometimes predators wander here, rodents are found, birds fly in and some types of insects can be seen.

Mountain-tundra altitudinal belt

Winter in the mountain-tundra zone is long, summer is short and cold. Average temperatures do not exceed +9°C. A strong wind constantly blows here, and the soil often freezes (only lichens, mosses, and low shrubs grow). This belt is not typical for all mountains: in warm latitudes it is absent; instead, an alpine or subalpine belt is located at this level.

Alpine altitudinal belt

The alpine belt is typical for mountains of the coastal type, and is almost never found in sharply continental latitudes. In the Himalayas it is located at an altitude exceeding 3.6 kilometers, in the Alps and Andes - 2.2 kilometers. During the short summer period, the meadows bloom profusely here, but winter is long and the slopes are completely covered with snow.

Desert-steppe belt

Characteristic of mountains that are located in desert and semi-desert areas of tropical latitudes and temperate zones. In drier areas it is located above the subalpine zone, in more humid areas it is located above the mountain forest zone. The landscape of this zone is first characterized by the presence of steppe, then semi-desert and desert.

Subalpine altitudinal zone

In this zone, meadows are mixed with small areas of forests. Sometimes geologists combine this zone with the alpine zone and call it the mountain-meadow belt.

Mountain-forest altitudinal belt

The mountain-forest belt is characterized by the presence of forest landscapes, while there is an extremely large amount of vegetation here and all its types largely depend on the latitude where the mountain is located. This belt goes downhill.

Human life in the mountains

Despite the fact that people settle mainly in the lowlands, at the base of the mountain, they long ago learned to benefit from almost the entire mountain surface and learn to make the most of relatively small spaces. For example, in the Alps (the highest mountain is Mont Blanc with a height of 4810 m), at the foot you can often see grape and garden plots, the middle part is sown with agricultural crops, and on alpine meadows graze cattle.

In these same mountains, thanks to a large amount of minerals, salt and precious metals, the mining industry is developed, paper and pulp are harvested from the forest, and hydroelectric power stations were built on the banks of the rivers.

People also actively use the mountains located on the American continent. A striking example is the Rocky Mountains (the largest mountain in the range is Elbert, 4.4 km high). The Rocky Mountains hide in their depths huge reserves of coal, lead, zinc, silver, shale, oil and natural gas. Despite the fact that relatively few people live here (four people per square kilometer, and the population of only a few cities exceeds fifty thousand),

The Rocky Mountains have extremely developed agriculture and forestry industries. Americans and Canadians successfully use mountain lands for grazing livestock and growing crops.

The Rocky Mountains are now an extremely popular destination among tourists: there are a huge number of national parks here, including Yellowstone, famous for its geysers and geothermal springs.

- Peak-shaped mountain peaks;
- Plateau-shaped mountain peaks;
- Domed tops mountains

- Mountain belts;
- Mountain countries;
- Mountain systems;
- Mountain ranges;
- Mountain groups;
- Single mountains.

Let's consider all the listed types and types of mountains in more detail.

Types and types of mountains by height:

The main feature by which mountains are classified is the height of the mountains. So, according to the height of the mountains there are:

Lowlands (low mountains) – mountain heights up to 800 meters above sea level.

Features of low mountains:

The tops of the mountains are round, flat,
The slopes are gentle, not steep, covered with forest,
Characteristically, there are river valleys between the mountains.

Examples: Northern Urals, spurs of the Tien Shan, some ridges of Transcaucasia, Khibiny Mountains on the Kola Peninsula, individual mountains of Central Europe.

Medium mountains (medium or mid-altitude mountains) – the height of these mountains is from 800 to 3000 meters above sea level.

Features of the middle mountains:

Medium-altitude mountains are characterized by altitudinal zonation, i.e. change of landscape with change in altitude.

Examples of medium mountains: Mountains of the Middle Urals, Polar Urals, island mountains New Earth, mountains of Siberia and the Far East, mountains of the Apennine and Iberian Peninsulas, Scandinavian mountains in northern Europe, Appalachians in North America and etc.

More examples of medium mountains (added at the request of visitors):

more than half of the territory Altai mountains(800-2000 meters),
mid-mountain ridges of the Eastern Sayans,
Aldan Highlands (height up to 2306 meters),
medium-altitude ridges of the Chukotka Plateau,
Orulgan ridge as part of the Verkhoyansk ridge (height - up to 2409 meters),
Chersky ridge (the highest point is Mount Chingikan with a height of 1644 meters),
Sikhote-Alin (the highest point is Mount Tordoki-Yani with a height of 2090 meters),
High Tatras (highest point - Mount Gerlachovsky Štit, 2655 m),
mid-mountain ridges of Transbaikalia (Daursky (up to 1526 m), Malkhansky (up to 1741 m), Dzhidinsky (up to 2027 m), Olekminsky Stanovik (average ridge height - from 1000 to 1400 m, maximum - 1845 m), Vitim Plateau (height from 1200 up to 1600 m) etc.).

Highlands (high mountains) – the height of these mountains is more than 3000 meters above sea level. These are young mountains, the relief of which is intensively formed under the influence of external and internal processes.

Features of the highlands:

The mountain slopes are steep, high,
The peaks of the mountains are sharp, peak-shaped, and have a specific name - “Carlings”,
The mountain ridges are narrow, jagged,
It is characterized by altitudinal zones from forests at the foot of the mountains to icy deserts at the tops.

Examples of highlands: Pamir, Tien Shan, Caucasus, Himalayas, Cordillera, Andes, Alps, Karakorum, Rocky Mountains, etc.

Types and types of mountains by origin.

The next characteristic by which mountains are classified is their origin. So, according to the origin of mountains, there are tectonic, volcanic and erosional (denudation):

are formed as a result of the collision of moving sections of the earth's crust - lithospheric plates. This collision causes folds to form on the surface of the earth. This is how they arise fold mountains . When interacting with air, water and under the influence of glaciers, the rock layers that form folded mountains lose their plasticity, which leads to the formation of cracks and faults. Currently, folded mountains have been preserved in their original form only in certain parts of the young mountains - the Himalayas, formed during the era of Alpine folding.

With repeated movements of the earth's crust, hardened folds of rock are broken into large blocks, which, under the influence of tectonic forces, rise or fall. This is how they arise fold-block mountains. This type of mountains is typical for old (ancient) mountains. An example is the Altai mountains. The emergence of these mountains occurred during the Baikal and Caledonian era mountain building, in the Hercynian and Mesozoic era they were subject to repeated movements of the earth's crust. The type of folded-block mountains was finally adopted during the Alpine folding.

formed during volcanic eruptions. They are usually located along fault lines in the earth's crust or at the boundaries lithospheric plates.

Volcanic there are mountains two types:

Volcanic cones. These mountains acquired their cone-shaped appearance as a result of the eruption of magma through long cylindrical vents. This type of mountain is widespread throughout the world. These are Fuji in Japan, Mount Mayon in the Philippines, Popocatepetl in Mexico, Misti in Peru, Shasta in California, etc.
Shield volcanoes. Formed by repeated outpouring of lava. They differ from volcanic cones in their asymmetrical shape and small size.

In areas of the globe where active volcanic activity occurs, entire chains of volcanoes can form. The most famous is the chain Hawaiian Islands of volcanic origin with a length of more than 1600 km. These islands are the tops of underwater volcanoes, whose height from the surface of the ocean floor is more than 5500 meters.

Erosion (denudation) mountains .

Erosion mountains arose as a result of the intensive dissection of stratified plains, plateaus and plateaus by flowing waters. Most mountains of this type are characterized by a table shape and the presence of box-shaped and sometimes canyon-type valleys between them. The last type of valley occurs most often when a lava plateau is dissected.

Examples of erosional (denudation) mountains are the mountains of the Central Siberian Plateau (Vilyuisky, Tungussky, Ilimsky, etc.). Most often, erosion mountains can be found not in the form of separate mountain systems, but within mountain ranges, where they are formed by the dissection of rock layers by mountain rivers.

Types and types of mountains according to the shape of the peak.

Another sign of mountain classification is the shape of the peak.

By the nature of the apical endings there are mountains: peak-shaped, dome-shaped, plateau-shaped, etc.

Added at the request of visitors:

Peaked mountain peaks.

Peaked mountain peaks- these are pointed mountain peaks, shaped like peaks, which is where the name of this species comes from mountain peaks. They are characteristic mainly of young mountains with steep rocky slopes, sharp ridges and deep crevices in river valleys.

Examples of mountains with peaked peaks:

Peak Communism (mountain system – Pamir, height 7495 meters)

Pobeda Peak (Tian Shan mountain system, height 7439 meters)

Mount Kazbek (mountain system – Pamir, height 7134 meters)

Pushkin Peak (mountain system – Caucasus, height 5100 meters)

Plateau-shaped mountain peaks.

Mountain peaks that are flat in shape are called plateau-shaped.

Examples of plateau-like mountains:

Front Range(English) FrontRange) is a mountain range in the southern part of the Rocky Mountains in the United States, adjacent to the Great Plains on the west. The ridge stretches from south to north for 274 km. Highest point- Mount Grays Peak (4349 m). The ridge is composed mainly of granites. The peaks are plateau-shaped, the eastern slopes are gentle, the western slopes are steep.

Khibiny(kild. Umptek) - the largest mountain range on the Kola Peninsula. Geological age is about 350 million years. The peaks are plateau-shaped, the slopes are steep with isolated snowfields. However, not a single glacier was discovered in the Khibiny Mountains. The highest point is Mount Yudychvumchorr (1200.6 m above sea level).

Amby(translated from Amharic as Mountain Fortress) is the name of the flat-topped hills and mesas in Ethiopia. They consist mainly of horizontal sandstones and layers of basalt. This determines the flat-topped shape of the mountains. Ambas are located at an altitude of up to 4,500 m.

Variety of mountains with plateau-like peaks are the so-called mesas(German) Tafelberg, Spanish Mesa- in the lane table) – mountains with a truncated flat top. The flat top of these mountains is usually composed of a durable layer (limestone, sandstone, traps, hardened lava). The slopes of mesa mountains are usually steep or stepped. Table mountains arise when stratified plains (for example, the Turgai Plateau) are dissected by flowing waters.

Famous mesas:

Amby, (Ethiopia)

Elbe Sandstone Mountains, (Germany)

Lilienstein, (Germany)

Buchberg, (Germany)

Koenigstein, (Germany)

Tafelberg (Thule), (Greenland)

Ben Bulben, (Ireland)

Etjo, (Namibia)

Gamsberg, (Namibia)

Grootberg, (Namibia)

Waterberg, (Namibia)

Szczelinec Wielkiy, (Poland)

Kistenstöckli, (Switzerland)

Tafelberg (Suriname)

Tepui, (Brazil, Venezuela, Guyana)

Monument Valley, (USA)

Black Mesa (USA)

Table Mountain, (South Africa)

Dining room (mountain, Caucasus).

Dome-shaped mountain peaks.

The dome-shaped, that is, rounded, shape of the top can be taken by:

Laccoliths are unformed volcanoes in the form of a hill with a magma core inside,

Extinct ancient heavily destroyed volcanoes,

Small areas of land that have undergone a dome-shaped tectonic uplift and, under the influence of erosion processes, have taken on a mountainous appearance.

Examples of mountains with a dome-shaped peak:

Black Hills (USA). This territory underwent a dome uplift, and most of The sedimentary cover was removed by further denudation and erosion. As a result, the central core was exposed. It consists of metamorphic and igneous rocks.

Ai-Nikola(Ukrainian Ai-Nikola, Crimean Catholicate. Ay Nikola, Ai Nikola) - a domed outlier mountain, the southeastern spur of Mount Mogabi near the western outskirts of the village of Oreanda. It is composed of Upper Jurassic limestones. Height - 389 meters above sea level.

Castel(Ukrainian Kastel, Crimean Catholicate. Qastel, Kaastel) - a mountain 439 m high on the southern outskirts of Alushta, behind the Professor's Corner. The dome of the mountain is covered with a forest cap, and chaos has formed on the eastern slope - boulders of stone, sometimes reaching 3-5 m in diameter.

Ayu-Dag or Bear Mountain(Ukrainian Ayu-Dag, Crimean Catholicate. Ayuv Dağ, Ayuv Dag) - mountain on South Coast Crimea, located on the border of Big Alushta and Big Yalta. The height of the mountain is 577 meters above sea level. This is a classic example of a laccolith.

Kara- Dag (Ukrainian Kara-Dag, Crimean Catholicate. Qara dağ, Kаara dag) - mountain-volcanic massif, Crimea. Maximum height - 577 m (Mount Holy). It is a heavily destroyed volcanic form with a dome-shaped top.

Mashuk- remnant magmatic mountain (laccolith mountain) in the central part of Pyatigorye in the Caucasus Mineralnye Vody, in the northeastern part of the city of Pyatigorsk. The height is 993.7 m. The peak has a regular dome shape.

Types and types of mountains by geographical location.

Various types mountains are divided by geographical location. On this basis, it is customary to group mountains into mountain systems, ridges, mountain ranges and single mountains.

Let's take a closer look:

Mountain belts - the largest formations. There are the Alpine-Himalayan mountain belt, stretching across Europe and Asia, and the Andean-Cordilleran mountain belt, passing through North and South America.

Mountain country – many mountain systems.

Mountain system – mountain ranges and groups of mountains that are similar in origin and of the same age (for example, the Appalachians)

Mountain ranges – mountains connected to each other, elongated in a line. For example, the Sangre de Cristo Mountains (North America).

Mountain groups – also interconnected mountains, but not stretched out in a line, but forming a group of indefinite shape. For example, Mount Henry in Utah and Bear Paw in Montana.

Single mountains

The highest mountains in the world. 7 peaks of the world.

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General concept. A mountain is usually called any pronounced rise, the base, slopes and top of which can be relatively easily distinguished. Free-standing mountains are extremely rare. Most often, mountains are combined into large groups, and their bases closely merge, forming a common skeleton, or the base of the mountains, clearly rising above the neighboring plain regions.

Based on the location of the mountains in the plan, they distinguish separately standing mountains, mountain ranges and mountain ranges. The first, that is, free-standing mountains, as already mentioned, are relatively rare and are either volcanoes or the remains of ancient destroyed mountains. The second, i.e. mountain ranges, are the most common type of mountainous areas.

Mountain ranges usually consist not of one, but of many rows of mountains, sometimes located very closely. As an example, we can point to the Main Caucasus Range, along the northern slope of which at least four more or less clearly defined rows of mountains are distinguished. Other mountain ranges have a similar character.

Mountain ranges They are vast mountain uplifts, equally developed in both length and width.

Large mountain ranges are rare. Most often they form separate sections of mountain ranges. An example of a large, highly dissected massif is the Khan Tengri mountain range.

The height of mountains is always measured vertically from the base to the top or from ocean level and also to the top. The height from the bottom to the top is called relative. The height from ocean level to the top is absolute. Absolute height makes it possible to compare the heights of mountains regardless of where they are located. In geography, absolute heights are almost always given.

Depending on their height, mountains are divided into low(below 1 thousand), average(from 1 to 2 thousand. m) And high(above 2 thousand m). When it comes to mountain ranges or mountainous areas, they usually include: small mountains, middle mountains And highlands. Examples of small mountains are the Timan Ridge, the Salair Ridge, as well as the foothills of many mountainous countries. Examples of middle mountains in the USSR are the Urals, the mountains of Transbaikalia, Sikhote-Alin and many others.

Types of mountains, identified on the basis of their height, are also characterized by relief features. For example, the highlands are characterized by sharp peaks, jagged ridges and deeply incised valleys (Fig. 235, 1). The highlands are also characterized by snowy peaks and glaciers. Mountains of medium height (or medium altitude) usually have rounded and seemingly smoothed shapes of the peaks and soft outlines of the ridges (Fig. 235, 2). The same, only even more smoothed forms are characteristic of small mountains. But here relative height becomes of great importance. If individual mountains of small mountains do not rise above the total surface above 200 m, then they are no longer called mountains, but hills.

Finally, mountains are also divided according to their origin. This division by origin is especially important for us, because it largely determines the character, structure, and location of the mountains. Depending on the origin (genesis) there are:

1) tectonic mountains,

2) volcanic mountains,

3) mountains are erosive.

We will analyze each of these types of mountains separately. Tectonic mountains, in turn, are divided into folded, folded-block and table-block.

Fold mountains. Let us recall that we call folded mountains those mountains in which folding clearly predominates. Fold mountains are found on all continents and many islands and are perhaps the most common, and fold mountains are the highest in height.

Mountains consisting of one fold (anticline) are relatively very rare. Much more often, mountain ranges consist of many parallel folds. In addition, the folds are usually much shorter in length than the ridges, due to which there may be several folds along the line of one ridge.

The very shape of the fold (in plan) largely determines the elongated shape of the ridges of folded mountains. Indeed, most of the folded mountains have a characteristic shape (Urals, Greater Caucasus, Cordillera).

Fold mountains usually consist of a series of parallel mountain ranges. In most cases, mountain ranges are located very close to one another, and, merging at their bases, form a wide and powerful mountain range. Mountain ranges stretch for hundreds and sometimes thousands of kilometers (the Caucasus Range is about 1 thousand. km, Ural over 2 thousand km). Most often, large ridges (in plan) have an arcuate shape and less often a rectilinear one.

Examples of arcuate ridges are the Alps, Carpathians, and Himalayas; examples of rectilinear ones are the Pyrenees, the Main Caucasus Range, the Urals, the southern part of the Andes, etc.

There are often cases when mountain ranges branch and even diverge like a fan. Examples of branching ridges are the Pamir-Alai mountains, Southern Urals and many others. Instead of the word branching, many authors use the word virgation. In cases where the branches of the ridges extend at a very acute angle or are located parallel to each other, the term “echelon” arrangement of the ridges is sometimes used.

Folds that appear on the surface of the Earth, under the influence of weathering, the work of flowing waters, the work of ice and the activity of other agents, immediately begin to collapse. Anticlines, as the most elevated parts of folded mountains, are destroyed first. The rapid destruction of anticlines is partly facilitated by the fracturing characteristic of bends. Therefore, when folds are severely destroyed, valleys often appear in place of anticlines. (anticlinal valleys), and in place of synclines there are mountain ranges. And the steeper the folds, the more intense the destruction of anticlines. As a result, the observed forms of mountains do not always correspond to structural forms, that is, forms determined by anticlines and synclines.

In cases where mountains, chains and ridges arise on the site of the wings of an anticline, the dip of the strata usually occurs only in one direction. The structure of such mountain chains is called monoclinal. The ridges or chains of mountains that arose on the site of the wings of a destroyed anticline are called cuestas, cuesta ridges, or cuesta chains. Asymmetry of slopes is typical for cuestas. The cuesta terrain is wide; distributed on all continents. An example is the northern foothills of the Caucasus.

Mesa Mountains are relatively rare. They arise on the site of lowland countries broken by faults, most often composed of horizontal strata. Elevated areas form mountains, usually table-type. The degree of elevation of areas can be different (from tens of meters to thousands of meters). It is difficult to notice any pattern in the distribution of rises and falls here. A typical example of table-block mountains is part of the Jura Mountains (Table Jura), as well as the Black Forest, Vosges, and some parts of the Armenian Highlands. An example of raising table forms to a lower height is Samarskaya Luka. There are many very high table rises in southern Africa.

Much more widespread fold-block mountains. The history of the formation of folded block mountains is quite complex. Let us consider, as an example, the main stages of the development of Altai. First, on the site of modern Altai (at the end of the Paleozoic), a high folded mountainous country arose. Then the mountains gradually collapsed and the country became a hilly plain. During the Tertiary period, this leveled section of the earth's crust, under the influence of the internal forces of the Earth, broke into pieces, with some parts rising and others falling. The result was a complex mountainous country, the ridges of which were located in a variety of directions. Examples of folded-block mountains in the USSR are the Tien Shan, Transbaikalia, Bureinsky Mountains and many others.

Volcanic mountains we are already quite familiar. Let us only note the special nature of the destruction of volcanic mountains under the influence of external agents.

Peaks high volcanoes, like the peaks of other high mountains, are subject to vigorous processes of physical weathering. Here, as in other mountains, under the influence of sharp temperature fluctuations, powerful accumulations of rocks, stones and boulders are formed. Just like in other mountains, “stone streams” descend down the slopes. The only difference is that the “stone flows” descend not only along the outer slopes of the cone, but also along the inner slopes of the crater. On higher volcanic mountains glaciers develop, the destructive work of which is already known to us.

Below the snow line, the main destroyers are rainfall. They cut through potholes and ravines radiating from the edges of the crater along the internal (crater) and external slopes (Fig. 236). These erosion grooves on the outer and inner slopes of the volcano are called Barrancos. At first, the barrancos are numerous and shallow, but then their depth increases. As a result of the growth of the outer and inner barrancos, the crater expands, the volcano gradually lowers and takes the shape of a saucer surrounded by a more or less raised rampart.

As for laccoliths, they first lose their outer cover, consisting of sedimentary rocks. First, this cover is destroyed at the top, then on the slopes; at the base, the remains of the cover, together with deluvial cloaks, last much longer. Laccoliths freed from the cover of uplifted sedimentary rocks are called opened(or prepared) laccoliths.

Erosion mountains. By the name erosion mountains we mean mountains that have arisen mainly as a result of the erosive activity of flowing waters. Such mountains can arise as a result of the dissection of plateaus and flat hills by rivers. An example of such mountains is the many interfluve mountains of the Central Siberian Plateau (Vilyuisky, Tungussky, Ilimsky, etc.). They are characterized by table shapes and box-shaped valleys, and in some cases even canyon-shaped ones. The latter are especially characteristic of a dissected lava plateau.

Much more often, mountains of erosion origin are observed within the middle mountains. But these are no longer independent mountain systems, but parts of mountain ranges that arose as a result of the dissection of these ranges by mountain streams and rivers.

Vertical zonation of landforms in the mountains. Each ridge, each mountain range often differs from each other in its relief forms. It is enough to compare, for example, the shapes of peaks and ridges with the highlands of the middle mountains. The former are distinguished by sharp peaks and jagged ridges, the latter, on the contrary, have soft, calm outlines of both peaks and ridges (Fig. 235).

This striking difference is due to many reasons, but the most important of them is their altitude above sea level, or, more precisely, the climatic conditions that exist at different altitudes. IN mountain zone, located above the snow line, the water is predominantly in a solid state (i.e., in the state of snow and ice). It is clear that there can be no streams or rivers there, and therefore, the erosive activity of flowing waters will be absent. But there are snow and ice there, which carry out tireless and highly peculiar work.

The situation is completely different in the lower zones, where the main agents are flowing waters. It is clear that the forms of relief of high mountains that arise under certain conditions will differ sharply from the forms of mountains that arise under other conditions.

As you rise upward, the physical-geographical conditions do not change immediately, but more or less gradually. It is clear that relief forms, determined by various physical and geographical conditions, will also change gradually. Let us dwell on the relief forms of the three most typical zones: high mountains, middle mountains and low mountains.

Landforms of high mountains. Frosty weathering, the work of snow and ice - these are the main factors that most affect mountains that rise above the snow line. The thin, clear air favors the heating of steep slopes devoid of snow cover. Clouds that temporarily cover the sun lead to rapid cooling. Thus, here at high altitudes, the rocks that make up the mountains are subject to not only daily, but also more frequent temperature fluctuations. The latter creates extremely favorable conditions for frost weathering, and the presence of steep slopes helps weathering products quickly roll down and expose the surface of rocks for further weathering.

Frost weathering in the mountains is greatly aided by winds, the speed of which, as is known, increases significantly with altitude. Therefore, the winds here are capable of blowing away (and blowing out of cracks) not only small dust particles, but also larger debris.

The variety of rocks that make up the mountains leads to uneven weathering. As a result, areas composed of stronger rocks turn out to be highly elevated above the general level of areas composed of less durable rocks. With further frost weathering, highly elevated areas take the form of sharp peaks, peaks and ridges, which gives the ridges of mountain ranges a jagged shape.

In cases where the rocks are homogeneous, the pointed peaks eventually round out and become flat. On their surface, as a result of the same frost weathering, entire “seas” of rocks and stones accumulate. On slopes, and especially on steep ones, the products of frost weathering slide down in huge “rock flows”, forming colossal screes; Screes below the snow line are washed away by flowing waters. Talus that descends into glacier feeding areas and onto the edges of glaciers is carried away by glaciers. This is how the steep slopes of high mountains are unloaded from frost weathering products.

In high mountains, in addition to frost weathering, as already mentioned, snow and ice carry out enormous destructive work.

We have already talked enough about what forms of relief arise as a result of glacial and steam-forming activity. These forms will be dominant within the highlands. Above the modern snow line, sharp peaks, peaks and jagged ridges with cirques and glacial cirques usually catch the eye. Near the snow line there are glacial valleys with moraines and cirques. Even lower are traces of ancient glaciers and pits, at the bottom of which there are lakes or swamps or simply a drainage funnel.

Highland landforms were first studied in the Alps. Hence, all high mountains with sharp peaks, peaks, sharp jagged ridges, ravines, snow and glaciers began to be called mountains alpine type. Along with this, all forms characteristic of high mountains are often called alpine forms.

Landforms of low and middle mountains. Let us now turn to the lower sections of the mountains, which, based on their heights and dominant forms, can be classified as small and medium mountains. There are no longer eternal snows or glaciers here.

Sometimes, however, there may be traces of ancient glaciations, more or less modified by the work of flowing waters and other agents. These are usually dilapidated troughs, carts and circuses, along the bottom of which there are lakes and rivers. In some places, the remains of moraines, smoothed rocks and typical glacial boulders have been preserved.

In the mountains medium height Frost weathering is much less pronounced, occurring only during cold periods of the year. True, chemical and organic weathering occurs more intensely here, but the area of distribution of this weathering is much smaller. This happens because the slopes of the mountains we characterize are more sloping, due to which weathering products more often remain in place and delay further weathering. In the same areas where rocks come to the surface, they quickly weather and take on various, sometimes very characteristic, shapes.

If above the snow line the main destroyers were frost weathering, snow and ice, then here the main destroyers are flowing waters.

Mountains are generally characterized by a large number of rivers and all kinds of watercourses. Even in desert countries, mountains are always rich in water, because the amount of precipitation usually increases with height. The Tien Shan and Pamir-Alai mountains in Central Asia, from where such powerful rivers as the Syr-Darya and Amu-Darya receive their food, can be very indicative in this regard.

Mountain rivers are distinguished by a large slope of their channels, rapid currents, and an abundance of rapids, cascades and waterfalls, which determines their enormous destructive power. Finally, it should be noted that mountain rivers, fed by meltwater from snow and glaciers, have a large rise in water levels every day in the summer, which also increases their destructive power. All this taken together leads to the fact that the mountain slopes are cut through by a large number of transverse valleys. The latter often have the character of gorges. Depending on the strength of the rocks composing their slopes, gorges can be very deep and narrow. But, no matter how strong the rocks are, the steep slopes of the gorges are still gradually destroyed, become sloping and the gorges turn into ordinary wide valleys.

If the height of the mountains does not exceed the height of the snow line, then all the main work of destroying the mountains is done by rivers. The upper reaches of mountain streams, cutting into the slopes, reach watershed ridges. Here they meet the headwaters of rivers on the opposite slope, and their valleys little by little unite and cut the mountain ranges into pieces. As the rivers continue to flow, the mountain ranges break up into separate mountains, which in turn fall apart. Thus, in place of mountain ranges, as a result of the work of flowing waters alone, hilly countries can appear. The lower the mountains become, the more sedimentary their slopes become, and the rivers flowing from the slopes can no longer have the same destructive power. Nevertheless, the rivers continue their work. They deposit destruction products at the bottom of valleys, fill basins and erode slopes. Ultimately, the mountains can be destroyed to the ground, and in their place a leveled, slightly hilly surface will remain. Only rare preserved, isolated mountains still remind one of the mountainous country that was once here. These remaining isolated mountains are called outliers mountains, or witness mountains(Fig. 237 a, b, c). The leveled, slightly hilly surface that remains in place of the mountains is called peneplain, or simply a leveled surface.

If areas of low and medium mountains find themselves in dry climate conditions (in deserts and semi-deserts), then wind becomes of great importance in the formation of small forms. The wind, as already mentioned, helps weathering, carrying away particles of the resulting loose rocks. In addition, in desert countries the wind often carries sand. Under the impact of grains of sand, resistant rocks are polished, while less resistant rocks are destroyed.

The process of destruction of mountains occurs so quickly that if the mountains stopped uplifting, they would all be destroyed to the ground within one or two geological periods. But this does not happen, because under the influence of the internal forces of the Earth, the growth of mountains (uplift) usually continues for a very long time. So, for example, if the Ural Mountains, which arose as a high mountainous country at the end of the Paleozoic era, had not experienced further uplifts, they would have disappeared long ago. But thanks to repeated uplifts, despite continuous destruction, these mountains continue to exist.

When mountains are destroyed, two cases are possible. The first case: the rise of mountains proceeds more slowly than their destruction. Under these conditions, the height cannot increase, but can only decrease. When the uplift of mountains occurs faster than destruction, then the mountains rise.

To understand the nature of each mountain we study, it is necessary to pay special attention to the following points:

1. For folded mountains - the time of formation of the first folds and the time of formation of the last folds. For blocky ones - the state of a given mountainous country before the onset of faults and the time of the first and last movements of layers of the earth's crust along cracks.

2. The state of the mountains at the beginning of the Ice Age and during the glaciation period.

3. The state and life of mountains in post-glacial times.

The first, in addition to the age of the mountains, gives us an idea of the main large forms and location of the ridges themselves. In addition, here we learn about the nature of rocks and the way they are deposited, which is of great importance in the further formation of mountains.

The second, i.e., the state of the mountains at the beginning of the Ice Age and during the glaciation period, is especially important for those mountains that were subject to glaciation. Glaciers, depending on their nature (continental ice, valley glaciers, etc.), can greatly change even large forms of mountain relief.

The state of the mountains in post-glacial times largely determines the nature of the details of the forms. Climate is of greatest importance in this case. For example, in cold climates, frost weathering and the work of snow and ice can occur at all altitudes. Therefore, here not only high mountains, but also mountains of medium height have alpine shapes (Anadyrsky, Koryaksky ridges, etc.).

By age, mountains are distinguished between young and ancient. However, one should distinguish between the geological and geomorphological ages of mountains. Geological age is the time when a folded structure first formed. Geomorphological age is the time of the last formation of mountainous relief. In nature there are mountains that formed as folded structures in the Caledonian era, but their relief was formed in Quaternary time under the influence of new orogenic movements. Geomorphologically ancient mountains have been subject to destruction for a long time. In relief, they most often appear as peneplains, or outlier mountains. The relief forms of ancient mountains are soft, with gentle slopes.

The slopes in conditions are quite humid climate covered with a thick cloak of deluvial-elluvial formations. The river valleys are well developed. Young mountains have a great height, a highly dissected surface, and a large range of heights. Valleys often have the character of gorges and gorges. As a rule, modern glaciers develop on them. The relief of young mountains is characterized by sharp, steep shapes. An example of such mountains are Caucasus Mountains.

Mountains are different: old and young, rocky and flat, domed and peaked. Some of them are covered with dense forests, others with lifeless stone deposits. But in this article we will talk about their height. Which mountains are medium and which are considered high?

Mountain as a landform

First of all, it is worth answering the question of whether this is a positive form of relief, characterized by a sharp and isolated elevation of the terrain. In any mountain, three main elements are clearly visible:

vertex;
foot;
slope.

Any mountain system on the planet is nothing more than a complex system valleys (depressions) and ridges consisting of dozens of individual peaks. All of them are external manifestations of the internal (endogenous) forces of the Earth - tectonic movements of the earth's crust and volcanism.

Mountains create the most beautiful and unique landscapes on the surface of our planet. They are distinguished by their unique soil cover, unique flora and fauna. But people settle in the mountains extremely reluctantly. According to statistics, about 50% of the earth's population lives at altitudes not exceeding 200 meters above sea level.

Classification of mountains in geomorphology. Mountains are medium, low and high

In geomorphological science, mountains are usually classified according to a number of characteristics: age, height, geographical location, genesis, shape of peaks, etc.

By their origin they can be tectonic, denudation or volcanic, and by age - old or young. Moreover, a mountain system whose formation time does not exceed 50 million years is considered young. By geological standards, this is a very small age.

Depending on the shape of their peak, mountains are:

peaked;
domed;
plateau-shaped (“table”).

Geographers distinguish mountains based on their altitude above sea level:

low;
average;
tall.

Sometimes in the literature you can find intermediate altitude types, for example, medium-high or medium-low mountains. It is immediately worth noting that mountains of medium height can be found in any part of the world. However, most of them are in Europe and Asia.

Middle Mountains: examples and height

8848 meters - reaches this mark highest peak world - Chomolungma, or Everest. The absolute height of the middle mountains is much more modest: from 1 to 3 km above sea level.

The most famous examples of such mountain systems are the Carpathians, Appalachians, Tatras, Apennines, Pyrenees, Scandinavian and Drakensberg Mountains, Australian Alps, Stara Planina. There are medium mountains also within Russia. These are the Eastern Sayan, Sikhote-Alin (pictured below) and others.

An important feature of the middle mountains is the presence of altitudinal zones. That is, the vegetation and landscapes here change with altitude.

Carpathians

The Carpathians are the largest mountain system in Europe, spanning eight countries. Linguists, explaining the origin of its name, came to the conclusion that this toponym has Proto-Indo-European roots and is translated as “stone”, “rock”.

The Carpathians stretch in an arc of one and a half thousand kilometers, from the Czech Republic to Serbia. And the highest point of this mountain system is located on the territory of Slovakia (Mount Gerlachovsky Štit, 2654 m). An interesting fact: between the Alps and the extreme eastern spurs of the Carpathians there are only 15 kilometers.

The Carpathians are young mountains. They formed in the Cenozoic. However, their outlines are smooth and gentle, which is more typical of older geological structures. This can be explained by the fact that the Carpathians are predominantly composed of soft rocks (chalk, limestone and clay).

The mountain system is divided into three conventional parts: Western, Eastern (or Ukrainian) and Southern Carpathians. It also includes the Transylvanian Plateau. are characterized by fairly high seismicity. Here is the so-called Vrancea zone, which “produces” earthquakes with a magnitude of 7-8.

Appalachia

Geomorphologists often call the Appalachians the identical twin of the Carpathians. In appearance they are not much different from each other. The Appalachian Mountains are located in the eastern part of North America, within two states (USA and Canada). They stretch from to the Gulf of Mexico in the south. The total length of the mountain system is about 2500 kilometers.

If the European Carpathians are young mountains, then the American Appalachians are a product of earlier Hercynian and Caledonian folds. They formed about 200-400 million years ago.

The Appalachian Mountains are rich in a variety of mineral resources. Coal, asbestos, oil, and iron ore are mined here. In this regard, this mountainous region is also very often called the historical “industrial belt” of the United States.

Australian Alps

It turns out that the Alps are not only in Europe. Residents of the smallest and driest continent can also go hiking in the real Alps. But only in Australia!

This mountain system is located in the southern part of the continent. It is here that the highest point in all of Australia is located - Mount Kosciuszko (2228 m). And on the slopes of these mountains the most long river mainland - Murray.

The Australian Alps are stunningly diverse in landscape terms. In these mountains you can find snow-capped peaks, deep green valleys, and lakes with clear water. The mountain slopes are decorated with bizarre-looking rocks. The Australian Alps are home to several picturesque national parks and excellent ski resorts.

Finally

Now you know which mountains are medium and which are high. Geomorphologists distinguish three types of mountain systems based on height. The middle mountains have an altitude of 1000 to 3000 meters above sea level. The Carpathians, Appalachians, and Australian Alps are the most striking examples of such mountain systems in the world.

Mountains vary in height, shape, age, origin, geographical location, etc. The article provides a description of the listed types of mountains.

Mountains by height

Lowlands

Low mountains or low mountains - mountain heights up to 800 meters above sea level.

Peculiarities:

The tops of the mountains are round, flat,
The slopes are gentle, not steep, covered with forest,
Characteristically, there are river valleys between the mountains.

Examples: Northern Urals, spurs of the Tien Shan, some ridges of Transcaucasia, Khibiny Mountains on the Kola Peninsula, individual mountains of Central Europe.

Srednegorye

Middle mountains (medium or mid-altitude mountains) - the height of these mountains is from 800 to 3000 meters above sea level.

Medium-altitude mountains are characterized by altitudinal zonation, i.e. change of landscape with change in altitude.

Examples of medium mountains: Mountains of the Middle Urals, Polar Urals, mountains of the island of Novaya Zemlya, mountains of Siberia and the Far East, mountains of the Apennine and Iberian Peninsulas, Scandinavian mountains in northern Europe, Appalachians in North America, etc.

Highlands

Highlands (high mountains) - the height of these mountains is more than 3000 meters above sea level. These are young mountains, the relief of which is intensively formed under the influence of external and internal processes.

Peculiarities:

The mountain slopes are steep, high,
The peaks of the mountains are sharp, peak-shaped, and have a specific name - “Carlings”,
The mountain ridges are narrow, jagged,
It is characterized by altitudinal zones from forests at the foot of the mountains to icy deserts at the tops.

Examples: Pamir, Tien Shan, Caucasus, Himalayas, Cordillera, Andes, Alps, Karakoram, Rocky Mountains, etc.

Mountains by shape

According to the nature of the summit endings, mountains are: peak-shaped, dome-shaped, plateau-shaped, etc.

Peaked mountain peaks

Peaked mountains are pointed mountain peaks that are shaped like peaks, hence the name of this type of mountain peak. They are characteristic mainly of young mountains with steep rocky slopes, sharp ridges and deep crevices in river valleys.

Examples of mountains with peaked peaks:

Peak Communism (mountain system - Pamir, height 7495 meters)
Pobeda Peak (Tian Shan mountain system, height 7439 meters)
Mount Kazbek (mountain system - Pamir, height 7134 meters)
Pushkin Peak (mountain system - Caucasus, height 5100 meters)

Domed mountain peaks

The dome-shaped, that is, rounded, shape of the top can be taken by:

Laccoliths are unformed volcanoes in the form of a hill with a magma core inside,
Extinct ancient heavily destroyed volcanoes,
Small areas of land that have undergone a dome-shaped tectonic uplift and, under the influence of erosion processes, have taken on a mountainous appearance.

Examples of mountains with a dome-shaped peak:

Black Hills (USA). The area was subject to dome uplift and much of the sedimentary cover was removed by further denudation and erosion. As a result, the central core was exposed. It consists of metamorphic and igneous rocks.
Ai-Nikola (Ukrainian Ai-Nikola, Crimean tat. Ay Nikola, Ai Nikola) is a domed outlier mountain, the southeastern spur of Mount Mogabi near the western outskirts of the village of Oreanda. It is composed of Upper Jurassic limestones. Height - 389 meters above sea level.
Kastel (Ukrainian Kastel, Crimean Catholicate. Qastel, Kaastel) is a mountain 439 m high on the southern outskirts of Alushta, behind the Professor’s Corner. The dome of the mountain is covered with a forest cap, and chaos has formed on the eastern slope - boulders of stone, sometimes reaching 3-5 m in diameter.
Ayu-Dag or Bear Mountain (Ukrainian Ayu-Dag, Crimean Catholicate. Ayuv Dağ, Ayuv Dag) is a mountain on the southern coast of Crimea, located on the border of Big Alushta and Big Yalta. The height of the mountain is 577 meters above sea level. This is a classic example of a laccolith.
Kara-Dag (Ukrainian Kara-Dag, Crimean Catholicate. Qara dağ, Kаara dag) is a mountain-volcanic massif, Crimea. Maximum height - 577 m (Mount Holy). It is a heavily destroyed volcanic form with a dome-shaped top.
Mashuk is a remnant magmatic mountain (laccolith mountain) in the central part of Pyatigorye on the Caucasian Mineral Waters, in the northeastern part of the city of Pyatigorsk. The height is 993.7 m. The peak has a regular dome shape.

Plateau-shaped mountain peaks

Mountain peaks that are flat in shape are called plateau-shaped.

Front Range Front Range) is a mountain range in the southern Rocky Mountains of the United States, adjacent to the Great Plains to the west. The ridge stretches from south to north for 274 km. The highest point is Mount Grays Peak (4349 m). The ridge is composed mainly of granites. The peaks are plateau-shaped, the eastern slopes are gentle, the western slopes are steep.
Khibiny (Kild. Umptek) is the largest mountain range on the Kola Peninsula. Geological age is about 350 million years. The peaks are plateau-shaped, the slopes are steep with isolated snowfields. However, not a single glacier was discovered in the Khibiny Mountains. The highest point is Mount Yudychvumchorr (1200.6 m above sea level).
Amba (translated from Amharic as Mountain Fortress) is the name of the flat-topped hills and mesas in Ethiopia. They consist mainly of horizontal sandstones and layers of basalt. This determines the flat-topped shape of the mountains. Ambas are located at an altitude of up to 4,500 m.

Mountains by age

By age, mountains are divided into:

Young mountains,
Old (ancient) mountains.

Young mountains formed over the last 50 million years. In these mountain systems, internal processes are very actively developing, accompanied by the formation of mountains, earthquakes, and sometimes even volcanic activity. The youngest mountains on Earth are those belonging to the continental and island rings Pacific Ocean. The Caucasus Mountains are recognized as the youngest mountains in Russia. Here is the highest mountain in Russia - Elbrus (5642 m). (In the picture on the left: The Himalayas are young mountains, geological age about 38 million years)

Features of the young mountains:

the process of growth of young mountains is still ongoing,
the relief is sharp, highly dissected,
the peaks of the ridges are sharp,
the mountain slopes are steep and high,
high absolute altitudes,
significant height amplitude,
the valleys of numerous rivers are presented in the form of gorges, gorges,
Young mountains are characterized by the development of glaciers.

Examples of young mountains are:

Alps,
Caucasus Mountains,
Carpathians,
Kopet-Dag,
Pamir,
Mountains of Kamchatka.

Old (ancient) mountains are several hundred million years old. They differ in that the internal processes in them have long since died down, while the external processes that influence the destruction of the mountains are still active. This will continue until the relief is completely leveled. On many modern plains there are areas where, by all indications, there were once ancient mountains. From these mountains, only roots remained in the depths, covered with a thick layer of sedimentary rocks.

Features of old (ancient) mountains:

were heavily damaged,
have less contrasting relief,
the elevation differences are small,
gentle slopes,
The river valleys are well developed.

Examples of old (ancient) mountains are:

Ural mountains,
Timan,
Yenisei Ridge,
Khibiny ( Kola Peninsula, geological age approximately 350 million years).

By origin

Tectonic mountains are formed as a result of the collision of moving sections of the earth's crust - lithospheric plates. This collision causes folds to form on the surface of the earth. This is how folded mountains arise. When interacting with air, water and under the influence of glaciers, the rock layers that form folded mountains lose their plasticity, which leads to the formation of cracks and faults. Currently, folded mountains have been preserved in their original form only in certain parts of the young mountains - the Himalayas, formed during the era of Alpine folding.

With repeated movements of the earth's crust, hardened folds of rock are broken into large blocks, which, under the influence of tectonic forces, rise or fall. This is how folded block mountains arise. This type of mountains is typical for old (ancient) mountains. An example is the Altai mountains. The emergence of these mountains occurred during the Baikal and Caledonian eras of mountain building; in the Hercynian and Mesozoic eras they were subject to repeated movements of the earth's crust. The type of folded-block mountains was finally adopted during the Alpine folding.

Volcanic mountains are formed during the process of volcanic eruptions. They are usually located along fault lines in the earth's crust or at the boundaries of lithospheric plates.

There are two types of volcanic mountains:

Volcanic cones. These mountains acquired their cone-shaped appearance as a result of the eruption of magma through long cylindrical vents. This type of mountain is widespread throughout the world. These are Fuji in Japan, Mount Mayon in the Philippines, Popocatepetl in Mexico, Misti in Peru, Shasta in California, etc.
Shield volcanoes. Formed by repeated outpouring of lava. They differ from volcanic cones in their asymmetrical shape and small size.

In areas of the globe where active volcanic activity occurs, entire chains of volcanoes can form. The most famous is the chain of Hawaiian Islands of volcanic origin, more than 1600 km long. These islands are the tops of underwater volcanoes, whose height from the surface of the ocean floor is more than 5500 meters.

Erosion (denudation) mountains

By geographical location

On this basis, it is customary to group mountains into mountain systems, ridges, mountain ranges and single mountains.

Mountain belts are the largest formations. There are the Alpine-Himalayan mountain belt, stretching across Europe and Asia, and the Andean-Cordilleran mountain belt, passing through North and South America.

Mountainous country - many mountain systems.

Mountain system - mountain ranges and groups of mountains that are similar in origin and have the same age (for example, the Appalachians)

Mountain ranges are interconnected mountains stretched out in a line. For example, the Sangre de Cristo Mountains (North America).

Mountain groups are also mountains connected to each other, but not elongated in a line, but forming a group of indefinite shape. For example, Mount Henry in Utah and Bear Paw in Montana.

Solitary mountains are mountains that are not connected to other mountains, often of volcanic origin. For example, Mount Hood in Oregon and Rainier in Washington.