What is weathering? Types of weathering

One of the most common problems in the maintenance of agricultural land is soil erosion. It takes place in arid regions in open areas. Most often this leads to natural weathering, which is struggled in different ways, usually based on the regulation of hydraulic engineering indicators of land cover. But there is also a broader 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 because of excessive aridity.

General information on weathering

Under weathering is understood the process of external impact on the rock, in which the destruction or decomposition of its material basis occurs. The factors that cause such phenomena can have different character - from chemical water to atmospheric reactions. In most cases, the minerals are affected by a combination of different factors that eventually lead to depletion of the rock. And in the question of what is weathering, one can not 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, in the destruction can participate and the reaction of gas action. 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 same agricultural activities.

Types of weathering

Typically, chemical and physical weathering processes are identified, which are often interrelated and complementary. Is that their intensity may differ depending on environmental conditions. But also in some regions the processes of biogenic and radiation influence are widespread. Moreover, it is these phenomena that often bear the most pronounced nature of destruction. Chemical and physical processes are still more natural and can be said to occur in a constant regime, only with varying degrees of influence on the structure of natural materials. Biogenic weathering can also be a consequence of already intensive chemical decomposition.

The activity of this or that weathering factor depends not only on the external impact, but also on the characteristics of the rock. Most often, experts consider a set of phenomena. Thus, as the primary factors that determine certain weathering processes, the climate, terrain features, tectonic characteristics, composition and structure of the rock are distinguished.

Process of physical weathering

Among the main causes of this kind of weathering specialists call sharp and regular temperature changes. If in the daytime the surface of the mineral heats up and expands, then at night against a background of cooling the reverse process of structure reduction takes place. As a result, there is a cracking and crushing of the rock into small particles. This is a kind of deformation, which, again, has a permanent character, albeit unobtrusive. Particularly pronounced physical weathering in cold regions, where often there are frosts. The fact is that moisture accumulating in the mineral structure during such periods hardens and crystallizes, which increases the 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 that are unstable in terms of tectonic structure.

The process of chemical weathering

Phenomena of this nature can also be associated with a large group of factors, not always contributing precisely to destruction. Depending on the chemical reaction affecting the structure of the rock, deformation processes and the formation of new minerals can also be observed. In both cases, there will be a qualitative change in the composition and structure of the object. In the list of immediate factors that activate chemical weathering, secrete water, oxygen and carbon dioxide. For example, water resources naturally act as a kind of rock solvents. The intensity of interaction between water and mineral depends on the chemical composition of the liquid. In this case, the reactions themselves can be different. So, on minerals of igneous rocks water influences through the hydrolysis reaction. Its result can be the replacement of alkaline elements with hydrogen ions.

Biogenic or organic weathering

As already noted, biological factors can have no less effect on minerals. These include the activities of plants, small rodents and especially microorganisms with fungi and bacteria. In complex, 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 weathering of nutrients in practice? This can be, for example, the activity of living organisms that crush the mineral in the soil layer. Thus, the root system of trees acts. And some types of mosses can also act as a source of chemical reaction, releasing acids, which further decompose individual components of the mountain conglomerate.

Peculiarities 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 immediately it is worth highlighting the natural solar radiation, which is part of the group of radiation factors, and the technogenic processes. In the second case, the weathering of rocks occurs as a result of human activity. A classic example is the work of polygons on which toxic waste is stored. Accordingly, the nearest arrays with rocks will be subject to both destructive effects and active degradation factors.

What is the weathering crust?

We will also deal with this issue. The processes of weathering can occur continuously or in periods. But in both cases the surface on which certain factors of qualitative deformation act, takes on a characteristic appearance. This will be the weathering crust, which is characterized by looseness and depleted chemical composition.

As a rule, the upper layers of such layers are less decomposed and differ in the presence of metal components. It can be, for example, hydroxides of silicon or aluminum. Then follows the zone in which iron hydroxides are present, the formation of which was influenced by chemical weathering with a lower intensity. In the lower strata of the crust, limestone and gypsum joints usually lie.

Weathering Products

Usually, in the process of weathering, there are stone fragments, sand particles, gravel, clay fractions and kaolin. In this case, the elements detached from the main rock can have different sizes and shapes - this depends on the specific conditions and weathering factors. In some cases, the formation of curum is possible. These are massive blocks and boulders formed from freshly broken above-mentioned fractions. The standard sizes of kurums vary from 1 to 2 m, although there are also instances that go far beyond this range. Most often, the formation of such blocks provides physical weathering, which can result in the creation of a stone shell with a curum flooring.

Conclusion

Weathering occurs not only with varying degrees of intensity, but also differs in stages of realization. The simplest example is the physical process of destruction due to the temperature effect. Further, a chemical reaction can also be connected, in which a liquid with active elements will participate. Now we should turn to the question of what is the weathering of an organic character. In part this is a process of biological destruction, which can naturally lead to the formation of new breeds. Accordingly, weathering can not be considered only as the destruction of the existing mineral. Even if the deformation ends at the stage of the 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.