Mountain systems are perhaps one of the most monumental and impressive creations of nature. When you look at the snow-covered peaks, lined up one after another for hundreds of kilometers, you involuntarily wonder: what kind of immense force created them?
Mountains always seem to people to be something unshakable, ancient, like eternity itself. But the data of modern geology perfectly demonstrate how changeable the relief of the earth's surface is. Mountains can be located where the sea once splashed. And who knows which point on Earth will be the highest in a million years, and what will happen to the majestic Everest…
Mechanisms for the formation of mountain ranges
To understand how mountains are formed, you need to have a good idea of what the lithosphere is. This term refers to the outer shell of the Earth, which has a very heterogeneous structure. On it you can find peaks thousands of meters high, and the deepest canyons, and vast plains.
The Earth's crust is formed by giant lithospheric plates, which are located inin constant motion and from time to time collide with edges. This leads to the fact that certain parts of them crack, rise and change the structure in every possible way. As a result, mountains are formed. Of course, the change in the position of the plates occurs very slowly - only a few centimeters per year. However, it was thanks to these gradual shifts that dozens of mountain systems formed on Earth over millions of years.
The land has both sedentary areas (mostly large plains are formed in their place, such as the Caspian Sea), and rather "restless" areas. Basically, ancient seas were once located on their territory. At a certain moment, a period of intense movement of lithospheric plates and pressure of the incoming magma began. As a result, the seabed, with all its variety of sedimentary rocks, rose to the surface. So, for example, the Ural Mountains arose.
As soon as the sea finally "recedes", the rock mass that appeared on the surface begins to be actively affected by precipitation, winds and temperature changes. It is thanks to them that each mountain system has its own special, unique relief.
How tectonic mountains are formed
Scientists believe the movement of tectonic plates is the most accurate explanation of how folded and blocky mountains are formed. When the platforms shift, the earth's crust in certain areas can be compressed, and sometimes even broken, rising from one edge. In the first case, folded mountains are formed (some of their areas can be found inHimalayas); another mechanism describes the occurrence of blocky (for example, Altai).
Some systems feature massive, steep, but not too divided slopes. This is a characteristic feature of blocky mountains.
How volcanic mountains are formed
The process of forming volcanic peaks is quite different from how folded mountains are formed. The name speaks quite clearly about their origin. Volcanic mountains arise in the place where magma erupts to the surface - molten rock. It can come out through one of the cracks in the earth's crust and accumulate around it.
In some parts of the planet, you can observe entire ranges of this type - the result of the eruption of several nearby volcanoes. Regarding how mountains are formed, there is also such an assumption: molten rocks, finding no way out, simply press on the surface of the earth's crust from the inside, as a result of which huge "bulges" appear on it.
A separate case - underwater volcanoes located at the bottom of the oceans. The magma that comes out of them is able to solidify, forming entire islands. States such as Japan and Indonesia are located precisely on land areas of volcanic origin.
Young and ancient mountains
The age of the mountain system is clearly indicated by its topography. The sharper and higher the peaks, the later it formed. Mountains are considered young if they were formed no more than 60 million years ago. This group includes, for example, the Alpsand the Himalayas. Studies have shown that they originated about 10 million years ago. And although there was still a huge amount of time before the appearance of man, compared to the age of the planet, this is a very short time. The Caucasus, Pamir and Carpathians are also considered young.
An example of ancient mountains is the Ural Range (its age is more than 4 billion years). This group also includes the North and South American Cordilleras and the Andes. According to some reports, the most ancient mountains on the planet are in Canada.
Modern mountain formation
In the 20th century, geologists came to an unequivocal conclusion: there are huge forces in the bowels of the Earth, and the formation of its relief never stops. Young mountains “grow” all the time, increasing in height by about 8 cm per year, the ancient ones are constantly being destroyed by wind and water, slowly but surely turning into plains.
A striking example of the fact that the process of changing the natural landscape never stops is the constantly occurring earthquakes and volcanic eruptions. Another factor influencing the process of how mountains are formed is the movement of rivers. When a certain piece of land is raised, their channels become deeper and cut harder into the rocks, sometimes paving entire gorges. Traces of rivers can be found on the slopes of the peaks, along with the remains of the valleys. It is worth noting that the same natural forces that once formed their relief are involved in the destruction of mountain ranges: temperatures, precipitation and winds, glaciers and underground sources.
Scientific versions
Modern versions of orogeny (the origin of mountains) are represented by several hypotheses. Scientists put forward the following probable causes:
- dive ocean trenches;
- drift (slip) of the continents;
- subcrustal currents;
- bloating;
- reduction of the earth's crust.
One of the versions of how mountains are formed is connected with the action of gravity. Since the Earth is spherical, all particles of matter tend to be symmetrical about the center. In addition, all rocks differ in mass, and the lighter ones eventually become "displaced" to the surface by heavier ones. Together, these causes lead to the appearance of irregularities in the earth's crust.
Modern science is trying to determine the underlying mechanism of tectonic change based on what mountains were formed as a result of a particular process. There are still many questions connected with orogeny that still remain unanswered.
