ABSTRACT

The reliability of radiocarbon dates from soils is a topic of continuing controversy. The dating of soils has immense potential for the provision of an absolute timescale for landform development, for the rates of operation of earth-surface processes, and for the reconstruction of environmental change. Soil organic matter has been subjected to varying degrees of decomposition, humification and translocation, processes that do not necessarily reach an equilibrium in surface soil profiles; neither do they necessarily cease following burial. Initiation of soil development at a site results in the establishment and gradual differentiation of a soil profile, one aspect of which is the accumulation of soil organic matter. Allochthonous material may be carried on to a soil surface by a wide variety of sub-aerial processes, such as colluvial, alluvial or aeolian transport. Root penetration and decomposition is a normal process in surface soils. Once soil burial has occurred, however, roots that penetrate through the overburden must be regarded as contaminants.