Silt is produced by the mechanical weathering of rock, as opposed to the chemical weathering that results in clays. This mechanical weathering can be due to grinding by glaciers, aeolian (wind) abrasion as well as water erosion of rocks on the bedss of rivers and streams. Silt is sometimes known as 'rock flour' or 'stone dust', especially when produced by glacial action.
Silt can occur as a deposit or as material transported by a stream or by a current in the ocean. Silt is easily transported in water and is fine enough to be carried long distances by air as 'dust'. Thick deposits of silty material resulting from aeolian deposition are often called loess (a German term) or limon (French). Silt and clay contribute to turbidity in water.
See also sediment.