Interglacial-glacial climatic signatures preserved in a regressive coastal barrier, southeastern Australia

Regressive barriers persisting in the landscape over interglacial-glacial cycles are important repositories of paleoclimatic signatures such as past sea level and regional aridity. The Gippsland region of Victoria contains a multi-barrier system formed during past interglacial-glacial cycles and the late-Holocene. An extensive series of parallel foredune ridges forming the elongate inner barrier was sampled for luminescence dating with ages indicating deposition ca.125,000-108,000 years ago coinciding with the later phase of the Last Interglacial (LIG) Marine Isotope Stage (MIS) 5e and the transition to MIS 5d. Ground Penetrating Radar (GPR) imaged beach-face reflectors within the LIG barrier indicate that sea level was within −2 to +3 m of present level during MIS 5e in this far-field location. Significant reworking of the barrier system through blowout and parabolic dune activity occurred between 23,000-18,000 years ago corresponding to the Last Glacial Maximum (LGM) with an estimated 160,000,000 m3 of coastal sediments eroded and redistributed. The morphological changes to this coastal barrier over the most recent interglacial-glacial cycle (MIS 5e to present) also imply significant landscape instability during the LGM in southeastern Australia and are further evidence for extension of the geographical range and intensity of aridity at this time.