Core concepts of paleopedology

The current renaissance of scientific interest in paleosols has brought a variety of views and approaches to paleopedology. Two main approaches have emerged for the description and labelling of paleosols. Geosols are ancient land surfaces, consisting of laterally connected suites of paleosols used for stratigraphic subdivision of sedimentary deposits. Pedotypes are individual kinds of paleosols named after localities like geosols. Pedotypes are used for mapping and describing individual profiles, usually for the purpose of paleoenvironmental interpretation. Both pedotypes and geosols are field-based labels for which genetic or interpretive considerations are at a minimum. They can be interpreted using at least three distinct approaches. Taxonomic uniformitarianism is based on the assumption that a paleosol is formed in a similar environment to a surface soil of the same type. The factor function approach interprets specific aspects of paleoenvironments from measured features of paleosols by comparison with paleoenvironmentally related variation of that feature in surface soils. Finally, the process model approach seeks to recreate soil-forming processes mathematically with input from measurable features of paleosols. Each approach has limitations, such as the need for proxy features to classify paleosols in systems designed for surface soils, the attainment of similar appearance of a paleosol by different pathways and the mathematical uncertainty of model assumptions. The approaches of classification, experimentation and modelling are not unique to paleopedology, being widespread among other sciences. Fundamental to paleopedology, however, are the concepts of profiles and soilscapes of the past. (C) 1998 Published by INQUA/Elsevier Science Ltd. All rights reserved.