Cover-beds as soil parent materials in midlatitude regions

In parts of southern France, the Russian Plain, south central Turkey, the western USA and in Germany, slopes are covered by deposits (cover-beds) formed by geomorphic processes not limited to linear discharges. Often, loess material is mixed into them. Cover-beds usually form sequences of two or more distinct layers, and their distribution depends on the geomorphic, climate-driven processes of their formation. As they influence pedogenesis, they contribute to the understanding of soil properties and soil distribution. Horizon boundaries occur at depths where cover-bed properties change. Where aeolian matter is mixed in, podzolisation is buffered but depletion of clay may occur; loess-rich cover-beds may entirely decouple pedogenesis from bedrock influence. In humid areas, soil-water stagnation is often associated with varying cover-bed bulk densities, particularly upon flat relief. In semiarid areas, deep soil profiles consist of multiple layer sequences often with argillic and calcic properties within the same horizons. They reflect several cycles of cover-bed deposition and incorporation of loess, alternating with decalcification accompanied and followed by clay translocation. This led to the overprinting of buried soils by pedogenic carbonate leached from younger sediments. Synchronous sediment and/or airborne carbonate accretion and pedogenesis, which is usually invoked to explain soil profiles with several calcic horizons, cannot apply to cover-beds.