The origin and stratigraphic significance of the Quaternary Waterloo Rock of the Botany Basin of south-east Australia

The Waterloo Rock is an informally defined, variably indurated layer widely encountered in the Quaternary deposits of the Botany Basin of south-east Australia. The unit has been identified as a regionally significant stratigraphic marker, as playing an important role in the hydrogeological behaviour of the Botany Sands Aquifer and as a distinctive component of the soils of the Tuggerah Soil Landscape of the Botany Lowlands. Yet no systematic account exists of its nature, origin and stratigraphic significance. The Waterloo Rock may develop in at least two distinct contexts: as a result of the precipitation of cementing agents in the B horizons of soils and as the product of deposition at or close to the groundwater table. Its origin is thus more complex than suggested by many commentators and the unit should not be employed as a simple indicator of the location of the palaeo-water table or the presence of a palaeosol. Nor may the deposits of the Waterloo Rock be correlated stratigraphically, contro...