What are the mountains in height. What are mountains? Volcanic mountains, folded mountains, blocky, domed mountains

Mountains are different: old and young, rocky and gently sloping, domed and peaked. Some of them are covered with dense forests, others - with lifeless stone placers. 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 landform, characterized by a sharp and isolated uplift of the terrain. In any mountain, three main elements are clearly visible:

• vertex;
• foot;
• slope.

Any mountain system of the planet is nothing but a complex system of 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 a peculiar 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 medium, low and high

In geomorphological science, it is customary to classify mountains according to a number of criteria: by age, height, geographical location, genesis, shape of peaks, etc.

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

According to the shape of their top, mountains are:

• peaked;
• domed;
• plateau-like ("canteen").

By height above sea level, geographers distinguish mountains:

• low;
• medium;
• high.

Sometimes in the literature one can also find intermediate high-altitude types, for example, medium-high or medium-low mountains. It should be noted right away 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 - this mark is reached by the highest peak in the world - Chomolungma, or Everest. Altitude medium mountains are 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 Dragon Mountains, Australian Alps, Stara Planina. There are middle mountains and within Russia. These are the Ural Mountains, Eastern Sayan, Sikhote-Alin (pictured below) and others.

An important feature of medium mountains is the presence of altitudinal zonation. That is, the vegetation and landscapes here change with height.

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 stretched 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 (mountain Gerlakhovski-Shtit, 2654 m). An interesting fact: between the Alps and the extreme eastern spurs of the Carpathians - only 15 kilometers.

The Carpathians are young mountains. They formed in the Cenozoic. However, their outlines are smooth, gentle, which is more typical for 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 conditional parts: Western, Eastern (or Ukrainian) and Southern Carpathians. It also includes the Transylvanian Plateau. are quite seismic. Here is the so-called Vrancea zone, which "produces" earthquakes with a force of 7-8 points.

Appalachians

Geomorphologists often refer to the Appalachians as an 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 Gulf of Mexico on South. The total length of the mountain system is about 2500 kilometers.

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

The Appalachians are rich in various mineral resources. Coal, asbestos, oil, iron ore are mined here. In this regard, this mountain region also very often referred to as 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 originates the most long river mainland - Murray.

The Australian Alps are stunningly diverse in landscape terms. In these mountains one can meet snow-capped peaks, and deep green valleys, and lakes with the purest water. The slopes of the mountains 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 according to height. The middle mountains have a height of 1000 to 3000 meters above sea level. The Carpathians, Appalachians, Australian Alps - these are the most striking examples of such mountain systems in the world.

Mountains occupy about 24% of all land. Most mountains in Asia - 64%, least of all in Africa - 3%. 10% of the population lives in the mountains the globe. And it is in the mountains that most of the rivers on our planet originate.

Characteristics of the mountains

By geographical location, mountains are combined into various communities, which should be distinguished.

. mountain belts- the largest formations, often stretching across several continents. For example, the Alpine-Himalayan belt runs through Europe and Asia, or the Andean-Cordillera, stretching through North and South America.
. mountain system- groups of mountains and ranges, similar in structure and age. For example, the Ural Mountains.

. mountain ranges- a group of mountains, elongated in a line (Sangre de Cristo in the USA).

. mountain groups- also a group of mountains, but not elongated in a line, but simply located nearby. For example, the Ber-Po Mountains in Montana.

. Solitary mountains- not related to others, often of volcanic origin (Table Mountain in South Africa).

Natural areas of mountains

natural areas in the mountains they are arranged in layers and are replaced depending on the height. At the foot, there is most often a zone of meadows (in the highlands) and forests (in the middle and low mountains). The higher, the more severe the climate becomes.

The change of belts is influenced by climate, height, topography of mountains and their geographical position. For example, continental mountains do not have a belt of forests. From the foot to the top, natural areas change from deserts to grasslands.

Mountain views

There are several classifications of mountains according to various criteria: by structure, shape, origin, age, geographical location. Consider the most basic types:

1. By age distinguish old and young mountains.

old called mountain systems which is hundreds of millions of years old. The internal processes in them have subsided, and the external ones (wind, water) continue to destroy, gradually comparing them with the plains. The old mountains include the Ural, Scandinavian, Khibiny (on the Kola Peninsula).

2. Height distinguish between low, medium and high mountains.

Low mountains (up to 800 m) - with rounded or flat tops and gentle slopes. There are many rivers in these mountains. Examples: Northern Urals, Khibiny, spurs of the Tien Shan.

Medium mountains (800-3000 m). They are characterized by a change in landscape depending on the height. This is the Polar Urals, Appalachians, mountains Far East.

High mountains (over 3000 m). Basically, these are young mountains with steep slopes and sharp peaks. Natural areas change from forests to icy deserts. Examples: Pamir, Caucasus, Andes, Himalayas, Alps, Rocky Mountains.

3. By origin they distinguish volcanic (Fujiyama), tectonic (Altai Mountains) and denudation, or erosional (Vilyuysky, Ilimsky).

4. According to the shape of the top mountains are peak-shaped (Communism Peak, Kazbek), plateau-shaped and table-shaped (Amby in Ethiopia or Monument Valley in the USA), domed (Ayu-Dag, Mashuk).

Climate in the mountains

The mountain climate has a number of characteristic features that appear with height.

Decrease in temperature - the higher, the colder. It is no coincidence that the peaks of the highest mountains are covered with glaciers.

The atmospheric pressure drops. For example, at the top of Everest, the pressure is two times lower than at sea level. That is why water in the mountains boils faster - at 86-90ºC.

The intensity of solar radiation increases. In the mountains, sunlight contains more ultraviolet light.

The amount of precipitation is increasing.

High mountain ranges delay precipitation and affect the movement of cyclones. Therefore, the climate on different slopes of the same mountain may differ. On the windward side there is a lot of moisture, sun, on the leeward side it is always dry and cool. A striking example is the Alps, where subtropics are represented on one side of the slopes, and a temperate climate dominates on the other.

The highest mountains in the world

(Click on the picture to enlarge the scheme in full size)

There are seven highest peaks in the world, which all climbers dream of conquering. Those who succeeded become honorary members of the "Seven Peaks Club". These are mountains such as:

. Chomolungma, or Everest (8848 m). Located on the border of Nepal and Tibet. Belongs to the Himalayas. It has the shape of a trihedral pyramid. The first conquest of the mountain took place in 1953.

. aconcagua(6962 m). It is the highest mountain in the southern hemisphere, located in Argentina. Belongs to the Andes mountain system. The first ascent took place in 1897.

. McKinley- the highest peak in North America (6168 m). Located in Alaska. First conquered in 1913. It was considered the highest point in Russia until Alaska was sold to America.

. kilimanjaro- the highest mark in Africa (5891.8 m). Located in Tanzania. First conquered in 1889. This is the only mountain where all types of the Earth's belts are represented.

. Elbrus- the highest peak in Europe and Russia (5642 m). Located in the Caucasus. The first ascent took place in 1829.

. Vinson Massif- the highest mountain of Antarctica (4897 m). It is part of the Ellsworth Mountains. First conquered in 1966.

. Mont Blanc- the highest point in Europe (many attribute Elbrus to Asia). Height - 4810 m. Located on the border of France and Italy, belongs to the mountain system of the Alps. The first ascent in 1786, and a century later, in 1886, Theodore Roosevelt conquered the summit of Mont Blanc.

. Pyramid of Carstens- the highest mountain in Australia and Oceania (4884 m). Located on the island of New Guinea. The first conquest was in 1962.

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 smallest ranges are located on the Australian continent, and almost all the mountain ranges of Antarctica are safely hidden under the ice.

Mountains are called part of the earth's crust, which, as a result of movement tectonic plates, volcanic eruptions or other processes occurring inside the planet, rose to a considerable height and began to rise above the plains. The height of some hills is small and is about three hundred meters, others rise more than eight thousand meters above sea level. The type of mountains is extremely diverse: it can be a separate peak, or it can be the longest mountain ranges, which include hundreds and even thousands of cones.

Considering that the structure of the mountains is ten percent sedimentary, and ninety percent igneous and metamorphic rocks (appeared 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 relief of the mountains consists of several parts:

• Mountain (hill) - a low or high cone-shaped mountain, consisting of a peak, slopes and a sole (the place where the slopes merge with the surrounding territory);
• Ridges are mountain heights strongly elongated in a line, the slopes of which, on the one hand, are often flat, on the other, are steep. They are also watersheds, since they direct the water of the rivers flowing downhill from different sides of the slopes in opposite directions. For example, the Rocky Mountains are elongated from the north in a southeast direction, while their length is about five thousand kilometers, due to which the Rocky Mountains are a watershed between the basins of the Pacific and Atlantic oceans;

• Saddle - a relief depression between two hills located next to each other, usually is the beginning of two hollows that go downhill in different directions;
• Hollow - an open depression in the relief lowering downhill at a slight slope, which at the bottom, when the slopes merge, forms a spillway line;
• Basin - located below sea level, a depression having a conical shape, which is characterized by a bottom, slopes and an edge line - the place where the slopes merge with the surface.

Formation theory

About how exactly the mountains of the world were formed, people throughout the history of their development put forward a variety of theories. At first it was 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 its surface to buckle, which causes the earth's crust to swell along the ocean margins.

This hypothesis did not explain in any way the presence of mountain systems within the mainland. Then they considered the version that the Earth is constantly decreasing in volume, and this happens abruptly and leads to deformation of the surface, where folding forms, some of which rise above the surface, and the other goes downhill.

Later, the idea appeared that the mountain system was formed during the drift of the continents. 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 earth's crust to rise and fall (go downhill), affecting the relief of the planet. Despite the fact that many people liked the idea, no scientifically based evidence was found to confirm it.

The modern hypothesis of mountain formation arose in the middle of the last century, when the movement of lithospheric plates was proved, during the collision of which a thinner plate goes under the neighboring one, forming elevations 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 mountains

Based on the theory of the movement of tectonic plates and soil analysis, it was found that each mountain system was formed at its own time. The age of young ranges is from 50 to 80 million years, while the 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 they 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 by volcanic eruptions. The young, growing mountain system is easily recognizable by its sharply defined relief, consisting of alternating peaks and ledges, the sharp shape of peaks, the presence of very steep and high slopes, which complicate both the ascent and descent from the mountain.

It differs from the younger ancient mountain system in that all processes inside it have long subsided, while external ones, causing erosion, continue to affect the surface of the Earth. An interesting fact: geologists have discovered more than one area on the plains, where previously there was 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 region: they appeared almost simultaneously with our planet.

As for the ancient mountains, which time has not wiped off 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 strong erosion. If in young mountains water streams flow in narrow gorges, then rivers old mountain flow along a well-defined wide river valley.

It is not uncommon for older mountain ranges to include young 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 Western Cordillera, which began to form more than 120 million years ago. It should be noted that the Rocky Mountains are still growing, therefore, in the region where they are located, earthquakes and post-volcanic phenomena are not uncommon.

Mountain views

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

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

Zoning

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

But giving a description of the low and medium 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 with a height of more than three thousand meters, it is worth considering: in order to climb to its top, you must overcome absolutely all the belts of our planet. Therefore, the weather in the mountains differs significantly from the climate of the plains located near them.

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

How many belts a high mountain will have depends largely on in what climate zone it is located (mountains near the equator have the largest number of zonal belts). 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 belts into several parts.

Nival high-altitude belt

The presence nival belt only a high mountain can boast: in the tropics, it begins at an altitude exceeding 6.5 km above sea level. m., the farther 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 snows (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 meet, birds fly in and you can see some types of insects.

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 ground often freezes (only lichens, mosses, and low shrubs grow). This belt is not typical for all mountains: it is absent in warm latitudes, instead of it, an alpine or subalpine belt is located at this level.

Alpine altitudinal belt

The Alpine belt is characteristic of mountains of the coastal type, and almost never occurs 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. In the short summer period, meadows bloom profusely here, but the winter is long and the slopes are completely covered with snow.

Desert-steppe belt

It is typical for mountains that are located in desert and semi-desert areas of tropical latitudes and in temperate zones. In more arid regions it is located above the subalpine belt, in more humid regions it is above the mountain-forest zone. The landscape of this zone is first characterized by the presence of a steppe, then semi-deserts and deserts.

Subalpine altitudinal belt

In this zone, meadows are mixed with small patches 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 the vegetation here is extremely abundant 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 have long since learned to benefit from almost the entire mountain surface and are learning 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 vineyards and orchards, the middle part is sown with crops, and cattle graze in alpine meadows.

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

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

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

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

Mountains can be classified according to different criteria: 1) geographical location and age, taking into account their morphology; 2) structural features, taking into account the geological structure. In the first case, mountains are subdivided into cordillera, mountain systems, ranges, groups, chains and single mountains.

The name "cordillera" comes from the Spanish word meaning "chain" or "rope". The cordillera includes ranges, groups of mountains and mountain systems of different ages. The Cordillera region in western North America includes the Coast Ranges, the Cascade Mountains, the Sierra Nevada, the Rocky Mountains, and many smaller ranges between the Rocky Mountains and the Sierra Nevada in Utah and Nevada. The Cordilleras of Central Asia include, for example, the Himalayas, the Kunlun and the Tien Shan.

Mountain systems consist of ranges and groups of mountains that are similar in age and origin (for example, the Appalachians). The ranges consist of mountains stretched out in a long narrow strip. The Sangre de Cristo Mountains, stretching in the states of Colorado and New Mexico for 240 km, usually no more than 24 km wide, with many peaks reaching a height of 4000–4300 m, are a typical ridge. The group consists of genetically closely related mountains in the absence of a clearly defined linear structure characteristic of the ridge. Mount Henry in Utah and Bear Po in Montana are typical examples of mountain groups. In many parts of the world there are single mountains, usually volcanic origin. Such, for example, are Mount Hood in Oregon and Rainier in Washington, which are volcanic cones.

The second classification of mountains is based on the endogenous processes of relief formation. Volcanic mountains are formed by the accumulation of masses of igneous rocks during volcanic eruptions. Mountains can also arise as a result of the uneven development of erosion-denudation processes within a vast territory that has experienced tectonic uplift. Mountains can also be formed directly as a result of tectonic movements themselves, for example, during arched uplifts of sections of the earth's surface, with disjunctive dislocations of blocks of the earth's crust, or during intense folding and uplift of relatively narrow zones. The latter situation is characteristic of many large mountain systems of the globe, where orogeny continues at the present time. Such mountains are called folded, although during the long history of development after the initial folding, they were also influenced by other mountain building processes.

Fold mountains.

Initially, many large mountain systems were folded, but in the course of subsequent development, their structure became very complicated. The zones of initial folding are limited by geosynclinal belts - huge troughs in which sediments accumulated, mainly in shallow oceanic settings. Before folding began, their thickness reached 15,000 m or more. The confinement of folded mountains to geosynclines seems paradoxical, however, it is likely that the same processes that contributed to the formation of geosynclines subsequently ensured the collapse of sediments into folds and the formation of mountain systems. At the final stage, folding is localized within the geosyncline, since, due to the large thickness of the sedimentary strata, the least stable zones of the earth's crust arise there.

A classic example of folded mountains is the Appalachians in eastern North America. The geosyncline in which they formed was much longer than modern mountains. For about 250 Ma, sedimentation took place in a slowly sinking basin. The maximum thickness of precipitation exceeded 7600 m. Then the geosyncline underwent lateral compression, as a result of which it narrowed to about 160 km. Sedimentary strata accumulated in the geosyncline were strongly folded and broken by faults, along which disjunctive dislocations occurred. During the stage of folding, the territory experienced intense uplift, the speed of which exceeded the rate of impact of erosion-denudation processes. Over time, these processes led to the destruction of mountains and the reduction of their surface. The Appalachians have been repeatedly uplifted and subsequently denuded. However, not all parts of the zone of initial folding experienced repeated uplift.

Primary deformations during the formation of folded mountains are usually accompanied by a significant volcanic activity. Volcanic eruptions appear during folding or shortly after its completion, and large masses of molten magma pour out in folded mountains, composing batholiths. They are often exposed during deep erosional dissection of folded structures.

Many folded mountain systems are dissected by huge overthrusts with faults, along which rock covers tens and hundreds of meters thick were displaced for many kilometers. In folded mountains, both fairly simple folded structures (for example, in the Jura Mountains) and very complex ones (as in the Alps) can be represented. In some cases, the process of folding develops more intensively along the periphery of geosynclines, and as a result, two marginal folded ridges and a central uplifted part of mountains with less development of folding are distinguished on the transverse profile. Overthrusts extend from the marginal ridges towards the central massif. Massifs of older and more stable rocks that limit the geosynclinal trough are called forelands. Such a simplified structure scheme is not always true. For example, in the mountain belt located between Central Asia and Hindustan, the sublatitudinally oriented Kunlun mountains are represented at its northern border, Himalayas - at the south, and between them the Tibetan Plateau. In relation to this mountain belt, the Tarim Basin in the north and the Hindustan Peninsula in the south are forelands.

Erosion-denudation processes in folded mountains lead to the formation of characteristic landscapes. As a result of the erosional dissection of the layers of sedimentary rocks crumpled into folds, a series of elongated ridges and valleys is formed. The ridges correspond to outcrops of more stable rocks, while the valleys are worked out in less stable rocks. Landscapes of this type are found in western Pennsylvania. With deep erosional dissection of a folded mountainous country, the sedimentary stratum can be completely destroyed, and the core, composed of igneous or metamorphic rocks, can be exposed.

Blocky mountains.

Many large mountain ranges were formed as a result of tectonic uplifts that occurred along faults in the earth's crust. The Sierra Nevada Mountains in California are a huge horn stretching approx. 640 km and a width of 80 to 120 km. The eastern edge of this horst was raised the highest, where the height of Mount Whitney reaches 418 m above sea level. The structure of this horst is dominated by granites, which form the core of a giant batholith, but sedimentary strata have also been preserved, accumulated in a geosynclinal trough in which the Sierra Nevada folded mountains were formed.

The Appalachians today are largely shaped by several processes: the original folded mountains were eroded and denuded and then uplifted along faults. However, the Appalachians cannot be considered typical blocky mountains.

A series of blocky mountain ranges lie in the Great Basin between the Rocky Mountains to the east and the Sierra Nevada to the west. These ridges were uplifted as horsts along the faults limiting them, and the final appearance was formed under the influence of erosion-denudation processes. Most of the ranges extend in the submeridional direction and have a width of 30 to 80 km. As a result of uneven uplift, some slopes turned out to be steeper than others. Long narrow valleys lie between the ridges, partially filled with sediments carried from adjacent blocky mountains. Such valleys, as a rule, are confined to subsidence zones - grabens. There is an assumption that blocky mountains Great Basin were formed in the zone of extension of the earth's crust, since most of the faults here are characterized by tensile stresses.

Arch mountains.

In many areas, land areas that have experienced tectonic uplift, under the influence of erosion processes, have acquired a mountainous appearance. Where the uplift took place in a relatively small area and had an arched character, arched mountains formed, a striking example of which are the Black Hills in South Dakota, which are approx. 160 km. This area experienced arch uplift, and most of the sediment cover was removed by subsequent erosion and denudation. As a result, the central core, composed of igneous and metamorphic rocks, was exposed. It is framed by ridges composed of more resistant sedimentary rocks, while the valleys between the ridges have been worked out in less resistant rocks.

Where laccoliths (lenticular bodies of intrusive igneous rocks) have been intruded into the sedimentary rock mass, the overlying deposits could also experience dome uplifts. A good example of eroded arched uplifts is Mount Henry in Utah.

The Lake District in the west of England also experienced an arch uplift, but of somewhat lesser amplitude than in the Black Hills.

Remaining plateaus.

Due to the action of erosion-denudation processes, mountain landscapes are formed on the site of any elevated territory. The degree of their severity depends on the initial height. With the destruction of high plateaus, such as Colorado (in the southwestern United States), a highly dissected mountainous relief. The Colorado Plateau, hundreds of kilometers wide, was uplifted to a height of approx. 3000 m. Erosion-denudation processes have not yet managed to completely transform it into a mountain landscape, however, within some major canyons, such as the Grand Canyon. Colorado, mountains a few hundred meters high arose. These are erosional 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 repeated uplifts, any area will eventually level out and turn into a low monotonous plain. Nevertheless, even there, isolated hills, composed of more stable rocks, will remain. Such remnants are called monadnocks after the name of Mount Monadnock in New Hampshire (USA).

volcanic mountains

there are different types. Volcanic cones, common in almost all regions of the globe, are formed by accumulations of lava and rock fragments erupted through long cylindrical vents by forces acting deep in the bowels of the Earth. Illustrative examples of volcanic cones are Mayon Mountains in the Philippines, Mount Fuji in Japan, Popocatepetl in Mexico, Misty in Peru, Shasta in California, etc. Ash cones have a similar structure, but are not so high and are composed mainly of volcanic slag - porous volcanic rock, outwardly like ashes. Such cones are found near Lassen Peak in California and northeastern New Mexico.

Shield volcanoes are formed by repeated outpourings of lava. They are usually not as tall and not as symmetrical as volcanic cones. There are many shield volcanoes in the Hawaiian and Aleutian Islands. In some areas, the centers of volcanic eruptions were so close together that the igneous rocks formed entire ridges that connected the originally isolated volcanoes. This type includes the Absaroka Range in the eastern part of Yellowstone Park in Wyoming.

Chains of volcanoes meet in long narrow zones. Probably the most famous example is the chain of volcanic Hawaiian Islands, stretching over 1600 km. All these islands were formed as a result of outpourings of lava and eruptions of detrital material from craters located on the ocean floor. If we count from the surface of this bottom, where the depths are approx. 5500 m, then some of the peaks of the Hawaiian Islands will be among the highest mountains in the world.

Thick layers of volcanic deposits can be cut by rivers or glaciers and turn into isolated mountains or groups of mountains. A typical example is the San Juan Mountains in Colorado. Intense volcanic activity here manifested itself during the formation of the Rocky Mountains. Lavas of various types and volcanic breccias in this area cover an area of ​​more than 15.5 thousand square meters. km, and the maximum thickness of volcanic deposits exceeds 1830 m. Under the influence of glacial and water erosion, the massifs of volcanic rocks were deeply dissected and turned into high mountains. Volcanic rocks are currently preserved only on the tops of the mountains. Below, thick strata of sedimentary and metamorphic rocks are exposed. Mountains of this type are found on eroded areas of lava plateaus, in particular the Columbian, located between the Rocky and Cascade Mountains.

Distribution and age of mountains.

Mountains are found on all continents and many major islands- in Greenland, Madagascar, Taiwan, New Zealand, British and others. The mountains of Antarctica are largely buried under the ice sheet, but there are individual volcanic mountains, such as Mount Erebus, and mountain ranges, including the mountains of Queen Maud Land and The land of Mary Byrd is high and well-defined in relief. Australia has fewer mountains than any other continent. In North and South America, Europe, Asia and Africa, cordillera, mountain systems, ranges, mountain groups and single mountains are represented. The Himalayas, located in the south of Central Asia, are the highest and youngest mountain system in the world. The longest mountain system is the Andes in South America, stretching for 7560 km from Cape Horn to caribbean. They are older than the Himalayas and apparently had a more complex history of development. The mountains of Brazil are lower and much older than the Andes.

IN North America mountains show a very wide variety in age, structure, structure, origin and degree of dissection. Laurentian Upland, occupying the territory from Lake Superior to Nova Scotia, is a relic of highly eroded high mountains formed in the Archaean more than 570 million years ago. In many places, only the structural roots of these ancient mountains remain. The Appalachians are intermediate in age. They first experienced uplift in the Late Paleozoic c. 280 million years ago and were much higher than now. Then they underwent significant destruction, and in the Paleogene ca. 60 million years ago were re-raised to modern heights. The Sierra Nevada mountains are younger than the Appalachians. They also went through a stage of significant destruction and re-uplift. The Rocky Mountains of the United States and Canada are younger than the Sierra Nevada but older than the Himalayas. The Rocky Mountains formed during the Late Cretaceous and Paleogene. They survived two major stages of uplift, the last being in the Pliocene, only 2–3 million years ago. It is unlikely that the Rocky Mountains have ever been higher than at present. The Cascade Mountains and Coast Ranges of the western United States and most of the mountains of Alaska are younger than the Rocky Mountains. The coast ranges of California are still experiencing very slow uplift.

Variety of structure and structure of mountains.

The mountains are very diverse not only in age, but also in structure. The Alps in Europe have the most complex structure. The rock strata there were exposed to unusually powerful forces, which was reflected in the intrusion of large batholiths of igneous rocks and in the formation of extremely diverse overturned folds and faults with huge amplitudes of displacement. In contrast, the Black Hills have a very simple structure.

The geological structure of mountains is as diverse as their structures. For example, the rocks that make up the northern part of the Rocky Mountains in the provinces of Alberta and British Columbia are mostly Paleozoic limestones and shales. In Wyoming and Colorado, most of the mountains have cores of granites and other ancient igneous rocks overlain by layers of Paleozoic and Mesozoic sedimentary rocks. In addition, various volcanic rocks are widely represented in the central and southern parts of the Rocky Mountains, but there are practically no volcanic rocks in the north of these mountains. Such differences are found in other mountains of the world.

Although in principle no two mountains are exactly the same, young volcanic mountains are often very similar in size and shape, as evidenced by the examples of Fujiyama in Japan and Mayon in the Philippines, which have regular cone-shaped shapes. However, note that many volcanoes in Japan are composed of andesites (an igneous rock of intermediate composition), while the volcanic mountains in the Philippines are composed of basalts (a heavier black rock containing a lot of iron). The volcanoes of the Cascades in Oregon are mostly composed of rhyolite (a rock containing more silica and less iron than basalts and andesites).

ORIGIN OF MOUNTAINS

No one can explain with certainty how mountains formed, but the lack of reliable knowledge about orogeny (mountain building) should not and does not prevent scientists from trying to explain this process. The main hypotheses for the formation of mountains are discussed below.

Submergence of ocean trenches.

This hypothesis proceeded from the fact that many mountain ranges are confined to the periphery of the continents. The rocks that make up the bottom of the oceans are somewhat heavier than the rocks that lie at the base of the continents. When large-scale movements occur in the bowels of the Earth, oceanic depressions tend to sink, squeezing the continents upward, and folded mountains form at the edges of the continents. This hypothesis not only does not explain, but also does not recognize the existence of geosynclinal troughs (depressions of the earth's crust) at the stage preceding mountain building. It does not explain the origin of such mountain systems as the Rocky Mountains or the Himalayas, which are removed from the continental margins.

Kober's hypothesis.

The Austrian scientist Leopold Kober studied the geological structure of the Alps in detail. Developing his concept of mountain building, he tried to explain the origin of large thrusts, or tectonic sheets, which are found both in the northern and southern parts of the Alps. They are composed of thick layers of sedimentary rocks subjected to significant lateral pressure, which resulted in the formation of recumbent or overturned folds. In some places, boreholes in the mountains open up the same layers of sedimentary rocks three times or more. To explain the formation of overturned folds and related thrusts, Kober suggested that the once central and South part Europe was occupied by a huge geosyncline. Thick strata of Early Paleozoic deposits accumulated in it under the conditions of an epicontinental marine basin that filled the geosynclinal trough. Northern Europe and Northern Africa were forelands composed of very stable rocks. When the orogeny began, these forelands began to approach each other, squeezing up the unstable young sediments. With the development of this process, which was likened to a slowly compressing vise, the uplifted sedimentary rocks were crushed, formed overturned folds, or advanced on the approaching forelands. Kober tried (without much success) to apply these ideas to explain the development of other mountainous areas. In itself, the idea of ​​lateral movement of land masses seems to explain the orogeny of the Alps quite satisfactorily, but turned out to be inapplicable to other mountains and therefore was rejected as a whole.

Continental drift hypothesis

proceeds from the fact that most mountains are located on the continental margins, and the continents themselves are constantly moving in a horizontal direction (drifting). During this drift, mountains are formed on the outskirts of the impending mainland. So, the Andes were formed during the migration South America to the west, and the Atlas Mountains - as a result of the movement of Africa to the north.

In connection with the interpretation of mountain building, this hypothesis encounters many objections. It does not explain the formation of the broad symmetrical folds that are found in the Appalachians and Jura. In addition, on its basis it is impossible to substantiate the existence of a geosynclinal trough that preceded mountain building, as well as the presence of such generally recognized stages of orogeny as the replacement of the initial folding by the development of vertical faults and the resumption of uplift. Nevertheless, in recent years much evidence has been found for the continental drift hypothesis, and it has gained many supporters.

Hypotheses of convection (subcrustal) currents.

For more than a hundred years, the development of hypotheses about the possibility of the existence of convection currents in the bowels of the Earth, causing deformations of the earth's surface, continued. From 1933 to 1938 alone, at least six hypotheses were put forward about the participation of convection currents in mountain building. However, all of them are based on such unknown parameters as the temperature of the earth's interior, fluidity, viscosity, crystal structure of rocks, compressive strength of various rocks, etc.

As an example, consider the Griggs hypothesis. It assumes that the Earth is divided into convection cells extending from the base of the earth's crust to the outer core, located at a depth of approx. 2900 km below sea level. These cells are the size of the mainland, but usually the diameter of their outer surface is from 7700 to 9700 km. At the beginning of the convection cycle, the masses of rocks enveloping the core are strongly heated, while on the surface of the cell they are relatively cold. If the amount of heat coming from the earth's core to the base of the cell exceeds the amount of heat that can pass through the cell, a convection current occurs. As the heated rocks rise up, the cold rocks from the surface of the cell sink. According to estimates, in order for the substance from the surface of the nucleus to reach the surface of the convection cell, it takes approx. 30 million years. During this time, long downward movements occur in the earth's crust along the cell periphery. The subsidence of geosynclines is accompanied by the accumulation of sediments hundreds of meters thick. In general, the stage of subsidence and filling of geosynclines lasts approx. 25 million years. Under the influence of lateral compression along the edges of the geosynclinal trough caused by convection currents, the deposits of the weakened zone of the geosyncline are crushed into folds and complicated by faults. These deformations occur without significant uplift of the folded strata disturbed by faults over a period of approximately 5–10 Ma. When the convection currents finally die out, the compressive forces are weakened, the subsidence slows down, and the thickness of the sedimentary rocks that filled the geosyncline rises. The estimated duration of this final stage of mountain building is approx. 25 million years.

The Griggs hypothesis explains the origin of geosynclines and their filling with sediments. It also reinforces the opinion of many geologists that the formation of folds and thrusts in many mountain systems proceeded without significant uplift, which occurred later. However, it leaves a number of questions unanswered. Do convection currents really exist? Earthquake seismograms testify to the relative homogeneity of the mantle - the layer located between the earth's crust and core. Is the division of the Earth's interior into convection cells justified? If there are convection currents and cells, mountains must appear simultaneously along the boundaries of each cell. How true is this?

The Rocky Mountain system in Canada and the United States is about the same age throughout its entire length. Its uplift began in the Late Cretaceous and continued intermittently during the Paleogene and Neogene, however, the mountains in Canada are confined to the geosyncline, which began to sag in the Cambrian, while the mountains in Colorado belong to the geosyncline, which began to form only in the Early Cretaceous. How does the hypothesis of convection currents explain such a discrepancy in the age of geosynclines, which exceeds 300 million years?

Hypothesis of swelling, or geotumor.

The heat released during the decay of radioactive substances has long attracted the attention of scientists interested in the processes occurring in the bowels of the Earth. The release of enormous amounts of heat from the explosion of the atomic bombs dropped on Japan in 1945 stimulated the study of radioactive substances and their possible role in mountain building processes. As a result of these studies, J.L. Rich's hypothesis appeared. Rich assumed that somehow large amounts of radioactive substances were concentrated locally in the earth's crust. When they decay, heat is released, under the influence of which the surrounding rocks melt and expand, which leads to swelling of the earth's crust (geotumor). When land rises between the geotumor zone and the surrounding area unaffected by endogenous processes, geosynclines form. Sediments accumulate in them, and the troughs themselves deepen both because of the ongoing geotumor and under the weight of sediments. The thickness and strength of rocks in the upper part of the earth's crust in the area of ​​the geotumor decreases. Finally, the earth's crust in the geotumor zone turns out to be so highly elevated that part of its crust slides along steep surfaces, forming overthrusts, crushing sedimentary rocks into folds and uplifting them in the form of mountains. This kind of movement can be repeated until the magma begins to pour out from under the crust in the form of huge lava flows. When they cool, the dome settles, and the period of orogeny ends.

The swelling hypothesis has not been widely accepted. None of the known geological processes makes it possible to explain how the accumulation of masses of radioactive materials can lead to the formation of geotumors with a length of 3200–4800 km and a width of several hundred kilometers, i.e. comparable to the Appalachian and Rocky Mountain systems. Seismic data obtained in all regions of the globe do not confirm the presence of such large geotumors of molten rock in the earth's crust.

Contraction, or compression of the Earth, hypothesis

is based on the assumption that throughout the history of the existence of the Earth as a separate planet, its volume has been constantly reduced due to compression. Compression of the inner part of the planet is accompanied by changes in the solid earth's crust. Stresses accumulate discontinuously and lead to the development of powerful lateral compression and crustal deformations. Downward movements lead to the formation of geosynclines, which can be flooded by epicontinental seas and then filled with sediments. Thus, at the final stage of development and filling of the geosyncline, a long, relatively narrow wedge-shaped geological body is created from young unstable rocks, resting on the weakened base of the geosyncline and bordered by older and much more stable rocks. With the resumption of lateral compression in this weakened zone, folded mountains are formed, complicated by overthrusts.

This hypothesis seems to explain both the contraction of the earth's crust, expressed in many folded mountain systems, and the reason for the emergence of mountains at the site of ancient geosynclines. Since in many cases compression occurs deep within the Earth, the hypothesis also provides an explanation for the volcanic activity that often accompanies mountain building. However, a number of geologists reject this hypothesis on the grounds that heat loss and subsequent compression were not large enough to allow for the formation of folds and faults that are found in modern and ancient mountainous regions of the world. Another objection to this hypothesis is the assumption that the Earth does not lose, but accumulates heat. If this is true, then the value of the hypothesis is reduced to zero. Further, if the core and mantle of the Earth contain a significant amount of radioactive substances that emit more heat than can be removed, then, respectively, both the core and the mantle expand. As a result, tensile stresses will arise in the earth's crust, and by no means compression, and the entire Earth will turn into a hot melt of rocks.

MOUNTAINS AS A HUMAN HABITAT

Influence of altitude on climate.

Let's consider some climatic features of mountain territories. Temperatures in the mountains drop by about 0.6°C for every 100 m of elevation. The disappearance of vegetation cover and the deterioration of living conditions high in the mountains are explained by such a rapid drop in temperature.

Atmospheric pressure decreases with altitude. Normal atmospheric pressure at sea level is 1034 g/cm2. At an altitude of 8800 m, which roughly corresponds to the height of Chomolungma (Everest), the pressure drops to 668 g/cm 2 . At higher altitudes large quantity heat from direct solar radiation reaches the surface, since the layer of air that reflects and absorbs radiation is thinner there. However, this layer retains less heat reflected by the earth's surface into the atmosphere. Such heat losses explain the low temperatures at high altitudes. Cold winds, cloudiness and hurricanes also contribute to lower temperatures. Low atmospheric pressure at high altitudes has a different effect on living conditions in the mountains. The boiling point of water at sea level is 100° C, and at an altitude of 4300 m above sea level, due to lower pressure, it is only 86° C.

The upper border of the forest and the snow line.

In descriptions of mountains, two terms are often used: "upper border of the forest" and "snow line". The upper limit of the forest is the level above which trees do not grow or hardly grow. Its position depends on average annual temperatures, precipitation, slope exposure and geographic latitude. In general, the forest boundary in low latitudes is located higher than in high latitudes. In the Rocky Mountains in Colorado and Wyoming, it passes at altitudes of 3400–3500 m, in Alberta and British Columbia it drops to 2700–2900 m, and in Alaska it is even lower. Above the forest line, in conditions of low temperatures and sparse vegetation, quite a few people live. Small groups of nomads move across northern Tibet, and only a few Indian tribes live in the high uplands of Ecuador and Peru. In the Andes, in the territories of Bolivia, Chile and Peru, pastures are higher, i.e. at altitudes over 4000 m, there are rich deposits of copper, gold, tin, tungsten and many other metals. All foodstuffs and everything necessary for the construction of settlements and the development of deposits have to be imported from the lower regions.

The snow line is the level below which snow does not remain on the surface all year round. The position of this line varies with annual solid precipitation, slope exposure, altitude and latitude. At the equator in Ecuador, the snow line runs at an altitude of approx. 5500 m. In Antarctica, Greenland and Alaska, it is only a few meters above sea level. In the Rocky Mountains of Colorado, the height of the snow line is approximately 3700 m. This does not mean at all that snowfields are widespread everywhere above this level, but they are not below. In fact, snowfields often occupy protected areas above 3700 m, but they can also be found at lower altitudes in deep gorges and on the slopes of the northern exposure. Since snowfields, growing every year, may eventually become a source of food for glaciers, the position of the snow line in the mountains is of interest to geologists and glaciologists. In many regions of the world, where regular observations of the position of the snow line were carried out at meteorological stations, it was found that in the first half of the 20th century. its level increased, and, accordingly, the size of snowfields and glaciers decreased. There is now indisputable evidence that this trend has been reversed. It is difficult to judge how stable it is, but if it persists for many years, it could lead to the development of an extensive Pleistocene-like glaciation that ended ca. 10,000 years ago.

In general, the amount of liquid and solid precipitation in the mountains is much greater than in the adjacent plains. This can be both a favorable and a negative factor for the inhabitants of the mountains. Atmospheric precipitation can fully meet the needs for water for domestic and industrial needs, but in case of excess it can lead to devastating floods, and heavy snowfalls can completely isolate mountain settlements for several days or even weeks. strong winds form snowdrifts that block roads and railways.

Mountains as barriers.

The mountains of the whole world have long served as barriers to communication and some activities. The only route from Central Asia to South Asia for centuries ran through the Khyber Pass on the border of modern Afghanistan and Pakistan. Countless caravans of camels and foot porters carrying heavy loads of goods traversed this wild place in the mountains. Famous passes in the Alps, such as St. Gotthard and Simplon, were used for many years as a connection between Italy and Switzerland. Today, through the tunnels laid under the passes, intensive railway traffic is maintained all year round. In winter, when the passes are littered with snow, all transport communication is carried out through tunnels.

Roads.

Due to the high altitudes and rugged terrain, the construction of roads and railways in the mountains is much more expensive than on the plains. Automotive and railway transport it wears out faster there, and the rails under the same load fail in a shorter period than on the plains. Where the bottom of the valley is wide enough, the railroad track is usually placed along the rivers. However mountain rivers often overflow their banks and can destroy large sections of roads and railways. If the width of the bottom of the valley is insufficient, the roadbed has to be laid along the sides of the valley.

Human activities in the mountains.

In the Rocky Mountains, in connection with the laying of roads and the provision of modern amenities (for example, the use of butane for lighting and heating houses, etc.), human living conditions at altitudes up to 3050 m are steadily improving. Here, in many settlements located at altitudes from 2150 to 2750 m, the number of summer houses significantly exceeds the number of houses of permanent residents.

The mountains are a relief from the summer heat. good example such a refuge is the city of Baguio, the summer capital of the Philippines, which is called "the city of a thousand hills." It is located just 209 km north of Manila at an altitude of approx. 1460 m. At the beginning of the 20th century. the Philippine government built government buildings, housing for employees and a hospital there, since in Manila itself it was difficult to establish an efficient operation of the government apparatus in the summer due to intense heat and high humidity. The experiment of creating a summer capital in Baguio proved to be very successful.

Agriculture.

In general, such features of the relief as steep slopes and narrow valleys limit the possibilities for the development of agriculture in the mountains of the temperate zone of North America. There, small farms mainly grow corn, beans, barley, potatoes and tobacco in some places, as well as apples, pears, peaches, cherries and berry bushes. In very warm climates, bananas, figs, coffee, olives, almonds, and pecans are added to the list. In the north of the temperate zone of the Northern Hemisphere and in the south of the southern temperate zone, the growing season is too short for most crops to mature, and late spring and early autumn frosts are common.

Pasture animal husbandry is widespread in the mountains. Where summer rainfall is plentiful, herbs grow well. IN Swiss Alps in summer, whole families move with their small herds of cows or goats to the high valleys, where they make cheese and make butter. In the Rocky Mountains of the United States, large herds of cows and sheep are driven from the plains to the mountains every summer, where they fatten their weight in rich meadows.

Logging

- one of the most important sectors of the economy in the mountainous regions of the globe, which ranks second after pasture animal husbandry. Some mountains are devoid of vegetation due to lack of rainfall, but in the temperate and tropical regions, most mountains are (or used to be) heavily forested. The variety of tree species is very large. Tropical mountain forests provide valuable hardwood (red, rose and ebony, teak).

Mining industry.

The extraction of metal ores is an important branch of the economy in many mountainous regions. Thanks to the development of copper, tin and tungsten deposits in Chile, Peru and Bolivia, mining settlements arose at altitudes of 3700–4600 m, where, due to the cold, strong winds and hurricanes create the most difficult living conditions. The productivity of miners there is very low, and the cost of mining products is excessively high.

Population density.

Due to the climate and topography mountainous areas often cannot be as densely populated as the plains. So, for example, in mountain country Bhutan, located in the Himalayas, has a population density of 39 people per square kilometer. km, while at a short distance from it on the low Bengal plain in Bangladesh, it is more than 900 people per 1 sq. km. km. Similar differences in population density in the mountains and on the plains exist in Scotland.

There are many types and types of mountains * Mountains differ in structure, shape, age, origin, height, geographical location, etc.

Consider the main types of mountains.

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) - the height of the mountains is up to 800 meters above sea level.

Features of lowlands:

• The tops of the mountains are rounded, flat,
• The slopes are gentle, not steep, overgrown with forest,
• The presence of river valleys between the mountains is characteristic.

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

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

Medium mountains features:

• For medium-altitude mountains, altitudinal zonality is characteristic, i.e. change of landscape with a change in altitude.

Examples of medium mountains: Mountains of the Middle Urals, Polar Urals, mountains of the island 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, etc.

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

• more than half of the territory of the Altai Mountains (800-2000 meters),
• mid-mountain ranges of the Eastern Sayan,
• Aldan Highlands (height up to 2306 meters),
• mid-altitude ridges of the Chukchi Highlands,
• the 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, 2090 meters high),
• High Tatras (The highest point is Mount Gerlachovsky Shtit, 2655 m),
• mid-mountain ranges of Transbaikalia (Daursky (up to 1526 m), Malkhansky (up to 1741 m), Dzhidinsky (up to 2027 m), Olekminskiy Stanovik (average height of the ridge - 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.

Highlands features:

• The slopes of the mountains are steep, high,
• The peaks of the mountains are sharp, peaked, have a specific name - "carlings",
• The ridges of the mountains are narrow, jagged,
• Characterized by altitudinal zonality from forests at the foot of the mountains to icy deserts at the peaks.

Highlands examples: Pamir, Tien Shan, Caucasus, Himalayas, Cordillera, Andes, Alps, Karakorum, Rocky Mountains, etc.

The next sign by which mountains are classified is their origin. So, by origin, mountains are tectonic, volcanic and erosional. (denudation):

are formed as a result of the collision of mobile sections of the earth's crust - lithospheric plates. This collision causes the formation of folds on the surface of the earth. This is how folded 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. At present, folded mountains in their original form have been preserved only in certain parts of the young mountains - the Himalayas, formed in the era of Alpine folding.

With repeated movements of the earth's crust, the hardened folds of rock break into large blocks, which, under the influence of tectonic forces, rise or fall. This is how fold-block mountains. This type of mountains is typical for old (ancient) mountains. An example is the mountains of Altai. The emergence of these mountains fell on the Baikal and Caledonian epochs of mountain building, in the Hercynian and Mesozoic epochs they underwent repeated movements of the earth's crust. The type of folded-blocky mountains was finally accepted during the Alpine folding.

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

Volcanic mountains are two types:

Volcanic cones. These mountains acquired a cone-shaped appearance as a result of the eruption of magma through long cylindrical vents. This type of mountains is widespread throughout the world. These are Fujiyama in Japan, Mayon Mountains in the Philippines, Popocatepetl in Mexico, Misty 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 with a length of more than 1600 km. These islands are the peaks of underwater volcanoes, the height of which is more than 5500 meters from the surface of the ocean floor.

Erosive (denudation) mountains .

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

Examples of erosion (denudation) mountains are the mountains of the Central Siberian Plateau (Vilyui, Tungus, Ilim, etc.). Most often, erosional 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.

Another feature of the classification of mountains is the shape of the peak.

By the nature of the vertex endings mountains are: peaked, dome-shaped, plateau-shaped, etc.

Peaked mountain peaks.

Peaked mountain peaks- these are the pointed peaks of the mountains, shaped like peaks, from where the name of this type of mountain peaks came from. Inherent mainly in young mountains with steep rocky slopes, sharp ridges and deep crevices in river valleys.

Examples of peaked mountains:

Communism Peak (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-like mountain peaks.

The tops of mountains that have a flat shape are called plateau-like.

Examples of plateau mountains:

Frontal ridge(English) FrontRange listen)) is a mountain range in the southern part of the Rocky Mountains in the United States, adjoining the Great Plains from the west. The ridge stretches from south to north for 274 km. The highest point is Mount Grace Peak (4349 m). The ridge is composed mainly of granites. The peaks are plateau-like, the eastern slopes are gentle, the western ones are steep.

Khibiny(kild. Umptec) - the largest mountain range on the Kola Peninsula. The geological age is about 350 million years. The peaks are plateau-like, the slopes are steep with individual snowfields. At the same time, not a single glacier was found in the Khibiny. The highest point is Mount Yudychvumchorr (1200.6 m above sea level).

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

A variety of mountains with plateau-like peaks are the so-called mesas(German Tafelberg, Spanish mesa- in lane. table) - mountains with a truncated flat top. The flat top of these mountains is usually composed of a solid layer (limestone, sandstone, traps, hardened lava). The slopes of mesas are usually steep or stepped. Table mountains arise when flowing waters dissect layered plains (for example, the Turgai plateau).

Famous mesas:

• Amby, (Ethiopia)
• Elbe Sandstone Mountains, (Germany)
• Lilienstein, (Germany)
• Buchberg, (Germany)
• Königstein, (Germany)
• Tafelberg (Thule), (Greenland)
• Ben Bulben, (Ireland)
• Etjo, (Namibia)
• Gamsberg, (Namibia)
• Grootberg, (Namibia)
• Waterberg, (Namibia)
• Szczelinec the Great, (Poland)
• Kistenstöckli, (Switzerland)
• Tafelberg (Suriname)
• Tepui, (Brazil, Venezuela, Guyana)
• Monument Valley, (USA)
• Black Mesa (USA)
• Table Mountain, (South Africa)
• Dining room (mountain, Caucasus).

domed mountain peaks.

Dome-shaped, that is, rounded, the shape of the top can take:

Laccoliths - not formed volcanoes in the form of a hill with a core of magma inside,

Extinct ancient heavily destroyed volcanoes,

Small areas of land that have undergone tectonic uplift of a domed character and, under the influence of erosion processes, have taken on a mountainous image.

Examples of mountains with a domed top:

Black Hills (USA). This area has undergone dome uplift and much of the sedimentary cover has been removed by further denudation and erosion. The central core was exposed as a result. It consists of metamorphic and igneous rocks.

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

Castel(Ukrainian Kastel, Crimean Tatar Qastel, Kastel) - 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 - stone blocks, sometimes reaching 3-5 m in diameter.

Ayu-Dag or Bear Mountain(Ukr. Ayu-Dag, Crimean Tatar. Ayuv Dağ, Ayuv Dag) - 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 laccolith.

Kara- Dag (Ukrainian Kara-Dag, Crimean Tatar. Qara dağ, Qara dag) is a mountain-volcanic massif, Crimea. Max Height- 577 m (Holy mountain). It is a strongly destroyed volcanic form with a domed top.

Mashuk- remnant magmatic mountain (mountain-laccolith) in the central part of Pyatigorye in the Caucasian Mineralnye Vody, in the north-eastern part of the city of Pyatigorsk. The height is 993.7 m. The top has a regular domed shape.

Different types of mountains are also separated 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 are the largest formations. Allocate the Alpine-Himalayan mountain belt, stretching through Europe and Asia, and the Andean-Cordillera 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 have the same age (for example, the Appalachians)

mountain ranges - interconnected mountains, elongated in a line. For example, the mountains of Sangre de Cristo (North America).

mountain groups - also interconnected mountains, but not elongated in a line, but forming a group of indefinite shape. For example, Mount Henry in Utah and Bear Po in Montana.

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