On geological agents They are those that shape the landscape and transform the characteristics of the rocks and the relief. The main geological agents are erosion, transportation, and sedimentation. One of the types of erosion is weathering. It is the process of disintegration or decomposition of rocks and minerals that are above the earth's surface.
In this article, we'll tell you what weathering is, what types there are, and how it affects the geology of the land.
What is weathering
As we have mentioned, it is the result of the changes that rocks and minerals experience when they are on the Earth's surface. These changes take place due to the continuous contact of the same with the atmosphere, biosphere, hydrosphere or certain geological agents such as wind and weather. The alteration of rock can lead to an increase in volume, a decrease in consistency, a reduction in particle size, or even the formation of other minerals.
There are several studies that reveal that weathering is an exogenous process. That is, this weathering is highly relevant in the analysis of relief forms. When we look at the relief of a landscape, we must understand that the landscape has been transformed over billions of years. This means that geological agents do not act on a human scale. The scale we must consider in this case is that of the geological time.
It must be said that erosion, whether caused by wind or water, can transform a relief or alter the formation of rocks, but only if enough years pass for this impact to have a significant impact on the formation of the landscape. This weathering It helps distinguish different types of soils as well as understand their compounds and nutrients.
One of the main factors influencing weathering is climate, the duration of the processes linked to it, and the intrinsic characteristics of the rock. Depending on the color, fissures, mineral proportions, and other characteristics, weathering will occur sooner or later. The composition of the minerals, such as the quartz, which can influence a rock's resistance to weathering processes. If you'd like to delve deeper into this topic, you can read about how these rocks form in [this article](https://www.meteorologiaenred.com/how-rocks-are-formed.html).
Types of weathering
The way rocks change is not always the same. There are two types of weathering depending on their origin. We have, on the one hand, chemical weathering and, on the other, physical weathering. Some studies have added a third type of weathering: biological weathering. Let's break down and analyze each type.
Physical weathering
This type of weathering causes rock to break down. Under no circumstances does it affect the chemical or mineral composition of the rock. During the physical weathering process, rocks gradually break down, allowing erosion to do its job better. The changing results can easily be seen in the rock's physical condition. These conditions are continually altered by the action of different environmental elements, including the following:
- Decompression: This is the fracture that occurs in more developed rocks. These fractures or cracks occur even when the pressure is not high. These cracks originate in rocks that are formed horizontally.
- Thermoclasty: It's like the action of the different temperature ranges that exist between day and night. It can be defined as a clash between the internal temperatures of the rock and its surroundings. These drastic changes that occur in some desert areas cause cracks in the rock. During the day, the sun causes the rock to heat up and expand, while at night it cools and contracts. These continuous processes of expansion and contraction are what cause the cracks that fracture the rock.
- Gelifraction: This is the breaking of rock due to the pressure of small pieces of ice that unfold over it. When water is frozen, its volume increases by up to 9%. This liquid, when present inside rocks, generates pressure on the walls, causing them to gradually fracture.
- Haloclasty: This is the process by which the salt exerts a certain pressure on the rock that produces its cracking. These are high concentrations of salt found in rock in various arid environments. When the rains fall, the salt is washed away and precipitates on the surface of the rock. In such a way, that the salt adheres to the cracks and the poles of the stones and, once crystallized, they raise their volume, increasing the force on the stones and generating their rupture. In most cases we find angular rocks of a small size that have been produced by this process called Haloclasty.
Chemical weathering
This is the process that causes a loss of rock bonding. Different atmospheric variables such as oxygen, carbon dioxide, and water vapor affect the rock. Chemical weathering can be understood in various phases. Let's define each phase:
- Oxidation: It is about the relationship between minerals and atmospheric oxygen and its continuous contrast.
- Dissolution: it is quite relevant in those minerals that are soluble in water.
- Carbonation: it is about the combination and the effect that the union of water with carbon dioxide produces.
- Hydration: It is the stage in which several minerals combine, producing an increase in the rock's volume. An example of this is what happens with gypsum.
- Hydrolysis: it is about the breakdown of certain minerals due to the work that the trillions of hydrogen do with the hydroxide in the water.
- Biochemistry: It is the disintegration of biological agents that exist in the soil and gives rise to the formation of organic acids.
Biological weathering
This type of weathering is what some experts have added. The animal and plant kingdoms are also responsible for external weathering. The action of certain roots, organic acids, water modify the anatomy of rocks. In addition, some organisms such as earthworms can also alter rock formation. This phenomenon is interesting, especially considering the impact on the soil and their formation over time. If you're interested, you can read more about the different types of [sedimentary rocks](https://www.meteorologiaenred.com/rocas-sedimentarias.html).
I hope that with this information you can learn more about weathering.
