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What are folded mountains: examples. Classification of mountains

The surface of the globe is forty percent occupied by mountains. This is a form of relief, representing a sharp rise among the rest of the territory, with significant differences in altitude - up to several kilometers. Sometimes the mountains have a pretty clear line of the sole at the slope, but more often - the foothills.

To find folded mountains on a map is very simple, because mountains as such are everywhere, on absolutely all continents and even on every island. Somewhere there are more, somewhere - less, as, for example, in Australia. In Antarctica, the ice layer hides them. The highest (and youngest) system of mountains is the Himalayas, the longest - the Andes, which stretched across all South America for seven and a half thousand kilometers.

How old is the mountain

The mountains are like people, they too can be young, mature and old. But if people are younger, the smoother, then the mountains have the opposite: a sharp relief and large heights indicate a young age.

In the old mountains and the relief is worn, smoothed, and the heights are not with such large swings. For example, the Pamirs are young mountains, and the Ural mountains are old, any map will show.

Characteristics of the relief

Folded mountains have an integrated structure, but for the most detailed inspection it is necessary to know the principles by which a general characterization of the relief is compiled. This applies not only to high mountains, but also literally meter deviations from the state of flat land - this is the so-called mountain microrelief. From the ability to correctly classify and depends on the exact knowledge of what mountains are.

Here it is necessary to consider such elements as the foot, valleys, slopes, moraines, passes, ridges, peaks, glaciers and many others, since on the earth there are various, including folded mountains.

Classification of mountains in height

The height can be classified very simply - only three groups:

  • The lowlands with a height of not more than a kilometer. Most often these are old mountains, destroyed by time, or very young, gradually growing. They have rounded peaks, gentle slopes on which trees grow. Such mountains are on every continent.
  • The middle reaches from a thousand to three thousand meters in height. Here is another, varying landscape, depending on the height - the so-called altitude zonality. Such mountains - in Siberia and the Far East, the Apennines, the Iberian Peninsula, Scandinavian, Appalachian and many others.
  • Highlands - more than three thousand meters. It is always a young mountain, prone to weathering, the effects of temperature changes and the growth of glaciers. Characteristic features: the troughs - the troughs of the valleys, the carlings - the sharp peaks, the glacial circuses - similar to the bowls of the depression on the slopes. Here the altitude is marked by belts - the forest at the foot, the icy deserts closer to the peaks. The term generalizing these characteristics is the "alpine landscape". The Alps are a very young mountain system, like the Himalayas, the Karakoram, the Andes, the Rocky and other folded mountains.

Classification of mountains by geographical location

Geographical position divides the relief into mountain ranges, mountain systems, mountain groups, mountain chains and solitary mountains. Of the largest formations are the mountain belts: the Alpine-Himalayan - across the whole of Eurasia, the Andijan-Cordillera - across the Americas.

Slightly less - a mountainous country, that is, a set of unified mountain systems. In turn, the mountain system consists of groups of mountains and ridges of the same age, most often folded mountains. Examples: Appalachian, Sangre de Cristo.

The group of mountains differs from the ridge in that it does not build its peaks by a narrow long strip. Solitary mountains are often of volcanic origin. By the form of the tops are divided into piciform, plate-like, domed and some others. Submarine mountains can form their islands with their peaks.

Formation of mountains

Orogenesis is the most complicated of processes, as a result of which rocks are creased into folds. What is folded mountains, scientists know reliably, but how they appeared - only hypotheses are considered.

  • Hypothesis one - oceanic depressions. The map clearly shows that all mountain systems are located on the outskirts of the continents. This means that the continental rocks are lighter than the bottom rocks of the ocean. The movements inside the Earth seem to squeeze the continent out of its interior, and the folded mountains are the bottom surfaces that emerged on the dry land. This theory has many opponents. For example, folded mountains - this is the Himalayas, which are clearly not bottom, as they are on the mainland. And according to this hypothesis it is impossible to explain the existence of depressions - geosynclinal troughs.
  • The hypothesis of Leopold Kober, who studied the geological structure of his Alps. These young mountains have not yet been subjected to destructive processes. It turned out that the tectonic large overthrusts were formed by huge thicknesses of sedimentary rocks. Alpine mountains have clarified their origin, but this path is absolutely different from the origin of other mountains, this theory was no longer possible anywhere else.
  • The continental drift is a very popular theory, also subject to criticism, as it did not explain the entire process of orogenesis.
  • Subcortical currents in the bowels of the Earth cause deformation of the surface and form mountains. However, this hypothesis has not been proved. On the contrary, mankind does not even know such parameters as the temperature of the earth's interior, let alone viscosity, fluidity and crystalline structure of deep rocks, compressive strength, and so on.
  • The hypothesis of Earth's compression - with its advantages and disadvantages. We do not know whether the planet accumulates heat or loses it if it loses - this theory is consistent if it does not accumulate.

What are the mountains

In the troughs of the earth's crust, all kinds of sedimentary rocks accumulated, which then crumpled and with the help of volcanic activity formed folded mountains. Examples: Appalachians on the east coast of North America, Zagros Mountains in Turkey.

The blocky mountains appeared because of tectonic uplifts along the faults in the earth's crust. As, for example, the Californian - Sierra Levada. But sometimes already formed folded suddenly begin to rise along the fault. So folded-blocky mountains are formed. The most typical are the Appalachians.

Those mountains that formed as folded strata of rocks, but were broken by young faults into blocks and climbed to different heights, also folded-blocky. The Tien Shan Mountains, for example, as well as the Altai Mountains.

The arched mountains are a tectonic elevation plus erosion processes in a small area. These are the mountains of the Lake District in England, as well as the Black Hills, located in South Dakota.

Volcanic formed under the influence of lava. There are two types: volcanic cones (Fujiyama and other similar ones) and shield volcanoes (less high and not so symmetrical).

Mountain climate

The mountain climate is radically different from the climate of any other territories. Temperatures drop more than half a degree, for every hundred meters of altitude. The wind is also usually very cold, which contributes to cloudiness. Frequent hurricanes.

With recruitment and atmospheric pressure decreases. On Mount Everest, for example, up to 250 millimeters of mercury. The water boils at eighty-six degrees.

The higher, the less vegetative cover, to its complete absence, and in the glaciers and snow caps there is practically no life.

Linear Zones

Thanks to the break-tectonic analysis, it was possible to make a definition of what folded mountains are, as a result of which they were formed and how dependent on deep planetary faults. All - both ancient and modern - mountain areas enter certain linear zones, which were formed only in two directions - north-west and northeast, repeating the direction of deep faults.

These belts are fringed by platforms. There is a dependence: the position and shape of the platform changes, and external forms change, and orientation in the space of folded belts. When forming the mountains, all is resolved by fault tectonics (blocks) of the crystalline base. Vertical movements of foundation blocks form folded mountains.

Examples of the Carpathians or the Verkhoyansk-Chukotka region show different types of tectonic movements in the formation of mountain folds. The Zagros mountains were also characteristic.

Geological structure

In the mountains everything is varied - from structure to structure. The rocks, for example, of the same Rockies vary throughout their entire length. In the northern part - Paleozoic shales and limestones, further - closer to Colorado - granites, igneous rocks with Mesozoic sediments. Still further - in the central part - volcanic rocks, which in the northern areas do not exist. The same picture will appear if we consider the geological structure of many other mountain ranges.

They say that there are no two identical mountains, but volcanic origin, for example, arrays often have a series of similar features. Correct contours of the cone of Japanese and Philippine volcanoes, for example. But we will now begin a detailed geological analysis, we will see that the saying is quite right. Many of Japan's volcanoes are composed of andesites (magma), and the Philippine rocks are basalt, much heavier because of the high iron content. And the Oregon Cascade Mountains have combined their volcanoes with rhyolite (silica).

Formation time of folded mountains

The formation of mountains throughout the process was due to the development of geosynclines in different geological periods, even in the folding times to the Cambrian. But the modern mountains are only young (relatively, of course) - Cenozoic uplifts. More ancient mountains were long ago leveled and were again raised by new tectonic movements in the form of blocks and arches.

The swardy-blocky mountains are most often revived. They are as common as the younger ones, folded. Today's Earth relief is neotectonics. One can study folding, which formed tectonic structures, if we consider the difference in the age of the mountains, and not the relief created by it. If Cenozoic is recent, it is difficult to think about the age of the earliest mountain formations.

And only volcanic mountains can grow up right before our eyes - during the eruption. Eruptions most often occur in the same place, therefore each portion of lava builds up the mountain. In the center of the mainland, the volcano is a great rarity. They, as a rule, form entire underwater islands, often forming arcs several thousand kilometers long.

How the mountains die

The mountains could stand forever. But they are being killed, albeit slowly, when compared to human life. It, first of all, frosts, splitting the rock into small pieces. So screes are formed, which then snow or ice are brought down, building up moraine ridges. It's water - rain, snow, hail - piercing the roads even through such indestructible walls. Water is collected in the rivers, which are arranged for themselves winding between the mountain spurs of the valley. The history of the destruction of the unshakable mountains, of course, is long, but inevitable. And the glaciers! Whole spurs, it happens, they are completely cut off by them.

Such erosion gradually reduces mountains, turning them into a plain: somewhere green, with deep rivers, somewhere deserted, sanding all the remaining hills. Such a surface of the Earth is called "Peneplain" - almost a plain. And, I must say, this stage is extremely rare. The mountains are reborn! The earth's crust starts to move again, the terrain rises, starting a new phase of terrain development.

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