Desilification
The desilication is a step in the flow of silicate weathering , in which, by hydrolysis and subsequent reaction of the resulting acid with water from silicate minerals orthosilicic acid (H 4 SiO 4 ) is formed. As a result of this process, the starting mineral loses a large part of its silicate content.
As the water-soluble orthosilicic acid produced during desilification is washed out, the mineral topsoil ( A horizon ) is depleted in silicates. Enrichment of the silica in the mineral subsoil ( B horizon ) through the reaction of the orthosilicic acid with water is possible under suitable conditions. The resulting silica in the reaction is very stable, and may thereby be formed by silicification silicate crusts ( silcrete ).
Desilification favors a soil formation process in which silicates are washed out of the topsoil . This process can be observed predominantly in tropical climates . The humid tropical climate favors desilification because the solubility of the silicon dioxide is greater there than in cool and moderate climatic conditions. The solubility of amorphous silicon dioxide also increases linearly with temperature, so that the dissolution and transport of silicon dioxide in the soil water is favored.
The leaching only creates pure leached soils if they remain untouched for long periods of time, since every intervention repeatedly creates a mixture in the topsoil, which counteracts the leaching.
literature
- Frank Ahnert: Introduction to Geomorphology . 1st edition. Verlag Eugen Ulmer, Stuttgart 1996, ISBN 3-8252-8103-5 , p. 108, 116 .