A Composite Regolith Profile at Ceduna, South Australia

Volume: 130Start Page: 197End Page: 20

Amino acid racemisation dating of a raised gravel beach deposit, Sellicks Beach, South Australia

Volume: 126Start Page: 21End Page: 2

TIMING EXTENT AND CHARACTER OF LATE CENOZOIC FAULTING ON THE EASTERN MARGIN OF THE MT. LOFTY RANGES SOUTH AUSTRALIA

Volume: 113Start Page: 63End Page: 6

Age and origin of alluvial sediments within and flanking the Mt Lofty Ranges, southern South Australia: a late quaternary archive of climate and environmental change

Quaternary alluvial sediments occur within and on the flanks of the Mt Lofty Ranges of southern South Australia. Within the ranges they occupy colluvium-filled bedrock depressions, alluvial-fan sequences at hill/plain junctions and river terraces that flank major streamlines in both locations. Sediments ranging in age throughout the Quaternary have been identified, but this paper focuses on those deposits of Late Quaternary age. Luminescence dating has verified a Last Interglacial age (132-118 ka) for the most widespread of the alluvial units, the Pooraka Formation. A younger, Marine Isotope Stage 3, alluvial unit, in places containing bones of the extinct marsupial Diprotodon, has also been identified. Deposition of the alluvial sediments is associated with relatively warmer and wetter conditions, whereas the valleys that they occupy were eroded under drier climatic conditions. A more widespread occurrence of Stage 3 units is expected to be present but has not yet been verified. Cold, arid environments are inferred from the presence of dunes (∼18 ka) deposited during the Last Glacial Maximum when stream valleys were incised. Grey/black mid-Holocene alluvium (Waldeila Formation), forming present-day floodplains and low river terraces, equates with the Holocene Hypsithermal. The sequence of climatic changes revealed by these sediments is correlated with evidence of Late Quaternary climatic change from other Australian locations. The identification of equivalent units in different tectonic settings reveals that sedimentation is largely climatically driven although active tectonism may accelerate the supply of sediments available for transport.R. P. Bourman; J. R. Prescott; D. Banerjee; N. F. Alley and S. Buckma

The age of the Pooraka Formation and its implications, with some preliminary results for luminescence dating

Volume: 121Start Page: 83End Page: 9

The age of the Pooraka formation and its implications, with some preliminary results from luminescence dating

Stratigraphic relationships, supported by luminescence dating, suggest that the Pooraka Formation spans a far greater time interval than previously recognised on the basis of radiocarbon dating and stratigraphic analysis of discrete sedimentary sections. It extends back as far as the Last Interglacial. Re-evaluation of the radiocarbon ages that indicate an interstadial age (i.e. Oxygen Isotope Stage 3; 45 to 30 ka BP) for the sediments is required. Alternatively, a considerable time interval for deposition of the Pooraka Formation would necessitate that the unit be diachronous across the landscape. An age extending back to the Last Interglacial (Oxygen Isotope Substage 5c; c. 125 ka BP) would provide the appropriate palaeo-climates and palaeo-environments for fluvial sedimentation. The revised age has implications for landscape evolution, archaeological and palaeomagnetic prospecting as well as the antiquity of the Diprotodon in the Adelaide area