One of the most common problems in maintaining agricultural land is soil erosion. It takes place in arid regions in open areas. Most often, natural weathering leads to this, which is fought in different ways, usually based on the regulation of the hydraulic characteristics of the land cover. But there is also a wider understanding of weathering, which affects not only the soil layer, but also rocks. In this case, it is appropriate to raise the question of what is the weathering of minerals? This is also a natural process of destruction, which, however, can occur not only due to excessive aridity.
Weathering Overview
Weathering refers to the process of external impact on a rock, during which the destruction or decomposition of its material base occurs. Factors causing such phenomena can have a different nature - from chemical water to atmospheric reactions. In most cases, minerals are affected by a combination of different factors that ultimately lead to depletion of the rock. Moreover, in the question of what weathering is, one cannot rely on the classical understanding of the activity of the wind itself or another exogenous factor. Even the usual chemical and physical processes do not fully reflect the completeness of this phenomenon. For example, gas reactions can also participate in the destruction. In particular, carbon dioxide and oxygen provide an active biochemical effect. Another thing is that the prerequisites for them can be connected with the result of human activity - for example, within the framework of the content of the same agriculture.
Types of weathering
Usually, chemical and physical weathering processes are distinguished, which are most often interconnected and complement each other. Unless their intensity may vary depending on environmental conditions. But also in some regions the processes of biogenic and radiation influence are widespread. Moreover, it is precisely such phenomena that often bear the most pronounced character of destruction. Chemical and physical processes are still more natural and can be said to occur in a constant mode, only with varying degrees of influence on the structure of natural materials. Biogenic weathering can also be the result of already intense chemical decomposition.
The activity of one or another weathering factor depends not only on external influences, but also on rock characteristics. Most often, experts consider a set of phenomena. So, as the primary factors that determine certain weathering processes, we single out the climate, features of the relief, tectonic characteristics, composition and structure of the rock.
Physical weathering process
Among the main causes of this kind of weathering, experts call sharp and regular temperature changes. If in the daytime the surface of the mineral heats up and expands, then at night against the background of cooling the reverse process of structural reduction occurs. As a result, cracking and crushing of the rock into small particles takes place. This is a kind of deformation, which, again, is permanent, albeit subtle. Physical weathering is especially pronounced in cold regions, where frosts often occur. The fact is that moisture accumulating in the structure of the mineral during such periods hardens and crystallizes, which increases stress and naturally leads to more intense cracking. They contribute to the destructive activity and vibration of the relief cover, which are often manifested in regions unstable from the point of view of the tectonic structure.
Chemical weathering process
Phenomena of this nature can also be associated with an extensive group of factors, moreover, not always contributing specifically to destruction. Depending on the chemical reaction affecting the structure of the rock, both deformation processes and the formation of new minerals can be observed. In both cases, a qualitative change in the composition and structure of the object will occur. In the list of direct factors that activate chemical weathering, water, oxygen and carbon dioxide are released. For example, water resources naturally act as a kind of solvent for rocks. The intensity of the interaction of water and mineral depends on the chemical composition of the liquid. Moreover, the reactions themselves can be different. So, minerals of igneous rocks are affected by water through a hydrolysis reaction. Its result may be the replacement of alkaline elements with hydrogen ions.
Biogenic or organic weathering
As already noted, biological factors can also have an equal effect on minerals. These include the activities of plants, small rodents, and especially microorganisms with fungi and bacteria. Together, these factors can provide a more serious destructive process than physical or chemical factors. But it also depends on the specific conditions of the terrain in which the rock lies. What is biogenic weathering in practice? This may be, for example, the activity of living organisms that crush a mineral in a soil layer. Thus, the root system of trees acts. And some types of mosses can also act as a source of a chemical reaction, releasing acids, which later decompose the individual components of mountain conglomerate.
Features of radiation weathering
One of the most dangerous is the process of radiation exposure. It is characterized by high intensity and duration, and in many cases it is simply impossible to stop it. But here it is worth highlighting natural solar radiation, which is included in the group of radiation factors, and technogenic processes. In the second case, weathering of rocks occurs as a result of human activity. A classic example is the operation of landfills that store toxic hazardous waste. Accordingly, the nearest massifs with rocks will be subject to both destructive effects and active decomposition factors.
What is weathering crust?
We will deal with this issue. Weathering processes can occur continuously or periodically. But in both cases, the surface on which certain factors of qualitative deformation act, acquires a characteristic appearance. This will be the weathering crust, which is characterized by friability and depleted chemical composition.
As a rule, the upper layers of such layers are less decomposed and are distinguished by the presence of metal components. It can be, for example, hydroxides of silicon or aluminum. This is followed by a zone in which iron hydroxides will be present, the formation of which was affected by chemical weathering with a lower intensity. In the lower layers of the crust, limestone and gypsum aggregates are usually located.
Weathering Products
Typically, stone fragments, sand particles, gravel, clay fractions and kaolin remain in the weathering process. Moreover, elements detached from the main breed can have different sizes and shapes - this already depends on the specific conditions and weathering factors. In some cases, the formation of kurum is also possible. These are massive blocks and boulders formed from freshly broken off fractions mentioned above. The standard sizes of kurums vary from 1 to 2 m, although there are specimens that go far beyond this. Most often, the formation of such blocks provides physical weathering, the result of which may be the creation of a stone shell with kurum flooring.
Conclusion
Weathering occurs not only with varying degrees of intensity, but also differs in stages of implementation. The simplest example is the physical process of destruction due to temperature exposure. Further, a chemical reaction may also be connected, in which a liquid with active elements will participate. Now it’s worth turning to the question of what is weathering of an organic nature. In part, this is a process of biological destruction, which can naturally lead to the formation of new breeds. Accordingly, weathering cannot be considered only as the destruction of an existing mineral. Even if the deformation ends at the stage of physical separation of a certain mass of particles, this change can contribute to the formation of new minerals or conglomerates, which is confirmed by the existence of kurum.