Eolian processes. Destroying activity of the wind
how wind is created;
in which parts of the Earth deserts have been formed;
how rocks are impacted by weathering processes.
to explain the term ‘eolian processes’;
to list the main factors conducive to the occurrence of eolian processes;
to use a selected example to discuss the influence of wind on the formation of terrain.
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The destructive force of the wind consists in the blowing away of fine eluvial material, or in the grinding of rock surface by the sand carried by the wind. Only in exceptional situations can strong winds tear off small fragments of brittle rocks. The hitting with fine particles of sand carried by the wind can damage even hard rocks. However, this process is very slow. Therefore, above all, the transporting and building forces of the wind play a huge role in the shaping of terrain. When blowing almost incessantly, the wind is able to carry and lay off, in other places, large amounts of tiny grains of rock. However, in order for these processes to take place, the following factors should occur at the same time:
the wind must be strong enough;
the rocks in the substrate must be heavily disintegrated;
the substrate must not be wet or covered with abundant vegetation.
For most of the day, and almost the entire year round, these conditions are fulfilled in deserts, and it is there that the ‘sculpting’ activity of the wind manifests itself most strongly. Hot deserts exist mainly in high atmospheric pressure areas in tropical zones, where atmospheric circulation causes extremely low rainfall. Deserts are also formed in subtropical and temperate zones in areas where distance from water bodies and the lay of the land contribute to the creation of extremely continental characteristics of the climate and the associated low rainfall. Depending on the nature of the substrate, there are three main types of deserts:
Wind also transforms the Earth’s surface on the sandy coasts of seas and oceans, on plowed farmland, in open‑pit mines, and on the forelands of glaciers and ice sheets, but only if the surface layer of soil and eluvium is dry. The processes associated with the activity of the wind are called eolian processeseolian processes.
Depending on the speed, wind can lift larger or smaller grains of sand and dust. Maybe these grains hit the rocks and slowly grind, groove, smoothen and scratch. This process is called a corrasioncorrasion. The closer to the Earth's surface, the more the sand is raised by the wind, and the process of corrasion is stronger. Therefore, rocks protruding above the desert surface are subject to the greatest damage in their lower part. As a result, various, sometimes very fanciful, rock forms are created. Rock fungi are rocks, which in the upper part are wider than in the lower part.
Move the elements to the corresponding groups.
glacier and ice sheet forelands, meadows and pastures, bogs and marshes, sandy coasts, rainforests, deserts
areas with intense wind-sculpting activities | |
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areas with low intensity of wind-sculpting activities |
Keywords
erg, hamada, eolian processes, serir
Glossary
erg – pustynia piaszczysta z wielką ilością lotnego piasku i wyraźnie ukształtowanymi wydmami; nazwa pochodzenia arabskiego
hamada – pustynia kamienista; najczęściej jest to równina pokryta odłamami i okruchami skalnymi, pozbawiona gleby i roślinności; nazwa pochodzenia arabskiego
procesy eoliczne – wszystkie rodzaje oddziaływania wiatru na rzeźbę terenu; ich rozwój uwarunkowany jest obecnością wystarczająco silnych wiatrów, mocnym rozdrobnieniem skał podłoża, ubóstwem szaty roślinnej i suchym klimatem
serir – pustynia żwirowa; nazwa pochodzenia arabskiego
korazja – proces polegający na szlifowaniu, żłobieniu, zdzieraniu i wygładzaniu powierzchni skał (podłoża skalnego) wskutek uderzeń ziaren piasku niesionego przez wiatr.