Orogenesis

Formation of mountain ranges

La orogenesis is the formation of great mountains and elevations of the land through certain movements of the tectonic plates. The fact that the Earth is rotating means that it acts as a kind of living entity and that it also undergoes transformations like living beings. The way it expresses changes in the terrain and the appearance of the lithosphere is through earthquakes. Through the movement of tectonic plates in the earth's crust, new mountains are formed by the process called orogenesis.

Do you want to know more about orogenesis and its types? We tell you everything.

Mechanism of orogenesis

Tectonic plate movement

Since the Earth has no modus operandi accelerated, let's say, we must bear in mind that its moment of action is not on a human scale. considering the geological time we can say that orogeny is a fairly slow process that occurs horizontally. It is a movement of the thinner layers of the Earth's surface in which the terrain shortens or lengthens, depending on the type of movement.

In some cases, there is neither elongation nor shortening, just a deformation. In these cases, the tectonic plates move in shear and have neither convergent nor divergent movement. The mechanism of orogenesis is also recognized as a kind of rejuvenation for the mountain ranges and mountains that exist on the continents.

As we know, after the passage of thousands of years, the mountains deteriorate and lose their peaks due to the continuous erosion of wind, rain, snow, and different types of weathering geological agents. By ello, the only way the Earth has to rejuvenate its surface is through orogeny or the formation of new mountains or mountain ranges.

The name of orogenesis comes from the set of "golds" which means mountain and "genesis" which is defined as origin or creation.

How is it produced?

Himalayan Formation

Since it is a very slow process and thousands of years pass, various phases occur through which orogenesis takes place. Let's see each one of them:

  • Folding. There are softer materials on the earth's surface that can mold and collide with each other. During these folds, the terrain begins to change. It can be seen in the formation of small hills.
  • Failure. As the folds of softer materials collide, there comes a time when harder materials collide. It is then that the folds that have formed are broken.
  • Thrust This is the last phase in which all the material is returned to its original position.

During the evolution of the orogeny, volcanic eruptions sometimes form. For example, this is what has happened in the case of the Andes. If the orogen that forms is mechanical or collision, it is less likely that volcanoes will arise. However, if the orogen is thermal, yes. In those of collision, spaces are formed full of folds and areas of thickening. This occurs because one continental plate ends up on another. We can see it clearly in the Alps.

As a result of these processes, elongated structures are formed that have slight arc-like bulges. These arches have the name of orogenic belts. They are easy to identify as they are shaped like stretched slices and have a position parallel to the rocks. Along the entire length, the belts are linked to the spaces where the tectonic plates subduct. It is here where volcanoes are formed.

Types of orogenesis

plates and mountain formation

Orogenesis is a process that can take place in several ways:

  • Symmetric orogenesis: it occurs when two continental plates compress into a depression in the earth's crust. This orogeny can be seen in reality in the Pyrenees, the Alps and the Himalayas.
  • Asymmetric orogenesis: in this case, it is formed because a continental plate collides with another oceanic one. When this happens, the sediments fold and accumulate in the subduction zones. Therefore, the oceanic plate subducts and the continental one predominates. An example of this type of orogenesis are the Rocky Mountains and the Andes.

The Alpine-type orogeny is part of the Tertiary period. In this formation, mountain ranges such as the Pyrenees, the Cantabrian Mountains and the Alps have been created. If we continue to connect the lines that have given rise to these mountain ranges, we can continue to the East connecting the Alps with the Caucasus and linking with the Himalayas. Without going any further, the Spanish mountain ranges such as Betica are formed with alpine orogenesis. In America we have the Andes and the Rocky Mountains.

Another type of orogeny is the Hercynian. It is estimated that it began to occur 300 million years ago. In different parts of the world, it has had an important influence on the Caledonian folding, affecting much of Europe, Tasmania, North America and the Appalachians.

Finally, the Caledonian orogeny is the one that takes place with the displacement of the tectonic plates that took place 400 years ago. In this fold the Caledonian chain was formed and vestiges of it can still be seen in Canada, North Asia, Australia and Scotland.

How orogeny affects the environment

Hills and creasing

The formation of mountains and mountain ranges influences the transformation of the environment at the geological level. As the relief changes, species have to adapt to new environments and modify their survival patterns. All of this is a complicated evolutionary process for humans to learn, given that our time on Earth is very short. We only live for about 100 years on average, so we cannot see anything, but nothing of the changes that exist. The only thing that we can notice the earthquakes resulting from these movements of the Earth's plates, but we cannot appreciate the displacement of the plates every year. We know that they move a few centimeters a year, something insignificant for the human scale.

With this information you will be able to know more about orogenesis.


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