STRATIGRAPHY VS PEDOGENESIS - PROBLEMS OF THEIR CORRELATION WITHIN COASTAL SEDIMENTARY FACIES

Stratigraphic differentiation of Quaternary coastal sedimentary sequen ces is frequently based upon the recognition of individual palaeosols. A number of assumptions are commonly made in the compilation of such lithostratigraphies; first, that the development of soil profiles (spo dosols) within coastal sedimentary sequences occur within stable sedim entary units and second, that one soil profile equals one sedimentary unit. After examining and thermoluminescence dating podzol (spodosol) profiles within 11 barrier and dune complexes along a 900 km stretch o f coastline in south-east Australia we can now show that such assumpti ons are not tenable. At eight of the ten locations examined the A and B horizons of these soils, although having the appearance of being int act and genetically related, revealed great discrepancies in age. We s uggest that coastal podzol profiles are particularly susceptible to re working primarily because of the variability in induration, and hence preservation potential, of successive horizons. Recognition of this si tuation as probably being the norm rather than a local anomaly suggest s that the practice of dividing sedimentary units into lithostratigrap hic units on the basis of palaeosols and then using this criteria as a basis for sampling and determining chronostratigraphies may well lead to erroneous interpretations especially when reconstructing Quaternar y environmental and geological histories.