We explain what orogenesis is, what types of relief it forms, its phases and types. Also, how tectonic plates intervene.
What is orogenesis?
Orogenesis is the type of geological process that usually forms mountains and mountain ranges on the earth's surface. This occurs when two tectonic plates meet and one of them, a continental crust, fractures and wrinkles on itself, generating widening and folding that, from our perspective, are mountains.
The orogenesis It also includes certain magmatic movements that throw new material to the surface especially granitic type. But this generally produces orogenic belts, which are elongated and parallel strips of rock, which exhibit very similar characteristics throughout the whole, and occur especially in subduction zones and volcanic zones.
This phenomenon occurs because one of the two plates submerges back into the mantle, below the crust of the other, suffering the physical effects of heat, pressure and gravity that modify its structure underground.
However, orogenesis is a long and slow process, which occurs in three phases or stages:
- Folding In which the soft elements of both plates collide with each other and form folds or deformations in the crust.
- Failure That is, failure production, when harder materials exert pressure and the folds break.
- Riding When one plate moves over or under the other.
This process is very important for the diversification of the relief of the Earth's crust and the renewal of mountain ranges. In fact, the earth's crust is considered a living entity, in the sense that, given enough time, it will change and rearrange itself, and where there were valleys there may be mountains, or vice versa.
Types of orogenesis
We can distinguish two different forms of this process:
- Symmetrical orogeny That which involves two continental plates, which are compressed together due to a depression in the Earth's crust, between two masses that approach each other. Such is the case of the mountain ranges of the Alps or the Himalayas, for example.
- Asymmetric orogeny That which involves a continental plate and an oceanic plate, the latter being below the first, so that the sediments accumulate in the subduction zone. Such is the case of the Andes mountain range, or the Rockies.
Continue with: Geomorphology
References
- “Orogenesis” on Wikipedia.
- “Orogenesis” in Enciclopedia.us.
- “Orogeny” in The Encyclopaedia Britannica.
