Pedostratigraphy (soil-stratigraphy) can be defined as the study of the stratigraphical and spatial relationships and implications of surface and buried soils. It has emerged as a key means of interpreting palaeosols; records of metastability in landscapes when rates of erosion and accumulation are slow. Past landscapes and their soils can be interpreted by analysing their environment of formation; however, post-depositional changes can be difficult to account for. A series of seminal studies in the 1950s and 1960s demonstrated the widespread utility and application of pedostratigraphy to understanding Quaternary and older environments. These studies led to inclusion of pedostratigraphic units in the North American Stratigraphic Code. The geosol was formulated as the fundamental pedostratigraphic unit, but its acceptance and utility is not universal. Similarly, different ideas on the status and nomenclature of palaeosols have emerged. Pedostratigraphy has become one of the fundamental tools in interpreting long continental records, and correlating them to marine oxygen-isotope records in deep ocean basins, as a means of documenting and understanding global climate change.
Palaeosols are widely used in Quaternary stratigraphy as stratigraphical markers. In particular, they are very important in loess sequences such as those in China, and elsewhere. It is important, however, to understand that fossil soils are not chronostratigraphical units. This is because the former can have boundaries that are time-transgressive and may cut across sediment sequences of differing ages. In contrast, the boundaries for chronostratigraphic units are isochronous.
*Modified from: Elias, S. 2007. Encyclopaedia of Quaternary Science. Elsevier, Amsterdam, 2847-2856.