Multisol - a proposal

This contribution proposes a term that can be useful for field descriptions of paleosols, with the ultimate goal of contributing to introduce the paleopedology into a tri-dimensional approach. A Multisol is defined as a soil or paleosol body that, maintaining an identifiable continuity, bifurcates into two or more layers located at different levels of the sedimentary column. The layers coalesce, disappear or bifurcate again over distances of tens or hundreds of meters. Field techniques in paleopedology are normally based on the study, description and sampling of a soil profile, that is, an excavation made at a point considered representative of a study area and all significant characteristics of the field are obtained from that precise point. In fact, this procedure represents a mono-dimensional approach to nature. Such a methodology is based on the current concept or implicit doctrine that soil is the result of pedogenetic processes acting on a stable surface not previously touched by pedogenesis and perfectly stable and devoid of erosion and sedimentation. Even concepts more complex than standard studies, such as pedocomplex and welded soils, are considered inside the theoretical basis that assumes that a soil (paleosol) is a unique, homogeneous, isolated sheet located on (or between) clearly different sediment strata or other geological bodies, which is in many cases a simplification. In some cases paleosols outcrop over hundreds of meters or more in cliffs and river banks, allowing the use of techniques of field geology and in consequence a tri-dimensional approach that is more correct in soil science. By applying the concept of Multisol and methods of geologic survey, four cases of Multisols in Argentina are described, each with different characteristics and environmental meaning. In theory, Multisols can develop in any environment where pedogenesis and sediment accumulation or erosion co-exist, ergo in most landscapes. In dynamic environments, as most landscapes are, different possibilities for development of Multisols appear.