- Ferrallitisation
Ferrallitisation is the process in which rock is changed into a
soil consisting ofclay (kaolinite ) andsesquioxide s, in the form of hydrated oxides of iron andaluminium . In humidtropical areas, with consistently high tempetures and rainfall for all or most of the year,chemical weathering rapidly breaks down the rock. This at first produces clays which later also break down to formsilica . The silica is removed byleaching and the sesquioxides of iron and aluminium remin, giving the charartistic red colour of many tropical soils. Ferrallitisation is the reverse ofpodsolisation , where silica remains and the iron and aluminum are removed. In tropicalrain forest s with rain throuhtout the year, ferrallitic soils develop. Insavanna areas, with altering dry and wet climates,ferruginous soil occur.
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