We explain what erosion is and what this physical process consists of. Also, how wind erosion and water erosion are carried out.
What is erosion?
Erosion is the wear that the different physical processes of the earth’s surface exert over time on soils, rocks and materials that could exert resistance to them. The main erosive agents are wind, water, ice and changes in temperature.
Erosion is not equivalent to weathering, a process of alteration or disintegration of rocks. For erosion to exist, a transport of matter or its movement is required, the repeated passage of which generates friction and wear on the materials, producing the relief, for example, of valleys, canyons, caverns, plateaus and other structures whose formation does not the hand of man intervenes.
Nevertheless, certain human activities can promote or even accelerate erosion. For example, logging for agricultural purposes removes the topsoil from the soil, leaving it exposed to rain or wind, which can eventually lead to infertility of the soil due to loss of nutrients.
In fact, under favorable conditions, erosion can be an intense force in soil desertification, which would contribute to the expansion of 35% of the land area that is already considered desert.
On the other hand, the action of wind or water can produce interesting natural monuments: natural arches or peculiar rock formations, such as those that exist in the Salar de Uyuni, in Bolivia, or in the Valley of the Moon in San Juan, Argentina.
Eolic erosion
This is the name given to the erosion product of the constant action of the wind over the years, transporting tiny particles of sand or rock that, in constant friction against soils, stones and mountains, are reducing their outer layers, carving them.
Wind erosion in desert areas it is responsible for shaping sand dunes, to displace them, or to form the stone deserts, called “erg”. In humid areas, on the other hand, it usually produces flat or slightly wavy reliefs, due to the transport of much finer materials, such as sedimentary clay deposits.
Water erosion
Water erosion is due to the action of the multiple forms of water, from the rain, the rivers, the seas and their phase changes according to the climatic seasons. Thus, the constant pounding of the waves on the sand on the shore reduce and round the pebbles that make up the sand, giving them their characteristic fineness and roundness, which is also the case with river stones.
On the other hand, the larger rocks resist the impact of the water without moving, but gradually losing particles of their outer layer, thus acquiring the roundness and smoothness that usually characterize them, or the holes and craters into which the drops of water fall incessantly .
The cliffs, likewise, or tidal flats, are the product of the action of the sea over the centuries, just as it happens with the riverbeds, in which the soil matter is eroded and sedimented at the same time.
The same occurs in glacial regions, in which the movement of ice, or even its constant formation and melting, have an impact on the surrounding materials, also causing their wear.