The dominant soil-forming processes in the Central East Sahara are based on physical weathering. They lead to the break up of rocks and stones as well as to the formation of various soil structures. These processes are controlled by temperature fluctuations, frostFrost, salt crystals, and wind abrasion (wind-sand-blower). By the first three weathering factors, the weathered product remains in situ, whereas under wind abrasion the weathered product is eroded and relocated. Insolation weathering is mainly due to temperature fluctuations. The greater the temperature fluctuation amplitude and the temperature change rate, the more intense the insolation weathering is. This also depends on the mineral composition of the stone, the color of the minerals, and the thermal conductivity of the rocks. Frost weathering occurs when sufficient moisture is present on frostFrost days. Under recent climatic conditions, this occurs only for a few days per year. Salt weathering occurs When salts crystallize from supersaturated salt solutions, high pressures can occur if the volumes of the solution and the precipitated crystals are larger than the volume of the supersaturated starting solution. Rock fragmentation also occurs when, the volume of the reaction product in a chemical reaction, is greater than that of the reactants such as e.g. limestones containing pyrite. Wind abrasion occurs when wind speeds exceed 25 kN (12.87 m/s). Sand can be eroded and transported. The sand transported by the wind acts like sandblasters that can rub solid rock and knock out rock particles that are blown away and deposited as aeolian sediment.