Video: Erosion processes

Natural elements, such as water, wind, and ice  cause a continuous wearing down of rocks and soils: this is erosion which shapes the landscape in many different ways.

Atmospheric agents can act to produce physical or chemical effects. The wind carries away fine particles of soil, redepositing them, sometimes very far away. This is also how it creates the dunes in deserts and on coasts, which it ceaselessly reshapes.

Rain washes out soils, but also dissolves limestone because of the Carbonic Acid it contains.

Alternate thawing and freezing breaks down rocks.

Flowing water, as in a river, slowly digs V-shaped valleys, above all when there is a rapid current and a heavy flow.

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In grinding down the rocky base beneath them, glaciers create large U shaped valleys (…) which  are still visible long after the glaciers themselves have disappeared.

Every year, billions of tons of sand, mud and rocks make up a large part of the sediments that are later transported elsewhere by air and water.

They end up accumulating, due to the force of gravity, above all at the bottoms of seas, lakes and large rivers, where they form thick sedimentary layers. With the passage of time and under certain conditions of pressure and temperature, these sedimentary layers are more and more compacted, to the point that they form sedimentary rocks, such as limestone and sandstone.

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As a result of geological movements, these rocks can find themselves back in the open air where they are in turn subjected to the erosive actions of the elements.