FERRUGINOUS WEATHERING UNDER COOL TEMPERATE CLIMATES DURING THE LATE PLEISTOCENE IN SOUTHEASTERN AUSTRALIA

Ferruginous and kaolinic profiles in cold or temperate lands have usua lly been attributed to former tropical climates. There is, however, mu ch evidence to suggest that ferruginous profiles in S.E. Australia for med by prolonged weathering under cool temperature climates. The new t echnique of U/Th dating of Fe/Mn pedogenetic concretions, supported by extensive TL dating of host sediments, shows that such profiles forme d in alluvial, colluvial, aeolian and marine sediments near Sydney dur ing the Last Glacial, when temperatures were depressed by about 5-degr ees-C below present levels. Given sufficient duration of weathering, p rofiles developed under cool temperature climates can mimic those foun d in the subtropics and tropics. Therefore, relict profiles of this ty pe found in high latitudes may not be reliable indicators of previous high temperatures. The correct analogy for much preglacial or intergla cial whethering in lands of the Northern Hemisphere may not be the tro pics, but the unglaciated temperate lands of the Southern Hemisphere.