Frost and soils: implications for paleosols, paleoclimates and stratigraphy

Frost is a pedogenetic agent. This paper describes the use of frost features in soil for paleoclimatic and stratigraphic interpretation. It is possible to differentiate periods of frost activity from those of temperate pedogenesis by macroscopic and microscopic criteria and to distinguish between soils with pre-, syn- and epigenetic frost effects. An experimental approach is necessary to determine initial frost effects because they are usually difficult to observe at natural active sites. Work with ecologists also clarifies the evolution of frost-affected soils under climatic and vegetational constraints. Vegetation has important effects on the thermal and hydraulic regimes of soils and on erosion susceptibility. The recognition of fossil cryosoils often allows the reconstruction of sequences of paleoclimatic events in periods or environments with little or no micropaleontological evidence. The interrelations between frost and other pedogenetic processes allow a better understanding of climatic evolution and deterioration throughout the Neogene and especially during the Quaternary and the Holocene. Most of the inherited frost features in European soils are younger than 480 ka BP. The differentiation between frost and tectonic perturbations is very important for calculation of soil erosional budgets.