TL chronology and stratigraphy of riverine source bordering sand dunes near Wagga Wagga, New South Wales, Australia

Abstract

Riverine source bordering dunes are found throughout the Murray Basin of southeastern Australia at the eastern and northern margins of Late Quaternary palaeochannels. The dunes are dominated by locally derived sand but often contain a minor calcareous clay component originating from a distant westerly source. In the bedrock-confined valley of the Murrumbidgee River near Wagga Wagga the dunes occur as discrete mounds on the floodplain or as drapes over the marginal valley side slopes. TL dating of three stratigraphic units within the dunes shows that phases of sand accumulation occurred between 15 and 25 ka in Oxygen Isotope Stage 2 (Clarendon Unit), between 35 and 60 ka in Stage 3 (Glenfield Unit) and between 80 and 120 ka in Stage 5 (Yarragundry Unit). The TL ages here, which show excellent agreement with those determined respectively for the Yanco, Kerarbury and Coleambally phases of palaeochannel activity on the Riverine Plain (J. Quat. Sci. 11 (1996) 311), extend the emerging regional model of Late Quaternary climatic and hydrologic change for southeastern Australia.