Summary

The timing and process for ferruginisation of the land surface in south-eastern Australia is uncertain but the features of a ferruginised landscape are ubiquitous. In some instances these may be quite young (i.e. less than 2 million years).

The ironstone gravels and even buckshot and mottles in many soils must be seen as weathering features rather than primary pedogenic products. Hence the proposition here that the gravels are litho relics rather than concretions. It is true that some of the gravels have concentric features indicating progressive precipitation, however, the cores of the gravels have a fabric that is similar to the underlying regolith (sandy depositional fabric). The concentric features should therefore be interpreted as the result of more recent pedogenic processes of redox, dissolution and re-precipitation of iron oxides, superimposed on the litho relic.

These mottling features have been observed in Rhyolite on the Dundas Tablelands, the Parilla sands, gravels at Stawell, as well as the Moorabool Viaduct and Dilwyn Formation.