THE LAST INTERGLACIAL SHORELINE IN SOUTHERN AUSTRALIA - MORPHOSTRATIGRAPHIC VARIATIONS IN A TEMPERATE CARBONATE SETTING

Coastal marine strata of last interglacial age are preserved extensive ly around the southern Australian coastline. The sedimentary facies ha ve many features in common with adjacent Holocene coastal facies and c ontemporary peritidal environments, but are partly lithified, mostly e levated, and laterally displaced inland. Sediments are dominantly biog enic skeletal carbonates of cool-temperate water affinities (foram-mol lusc-coralline alga association). Surficial calcrete development has a ided preservation of morphostratigraphic forms and sedimentary structu res. Large coastal barrier complexes comprising aeolian dune, foredune and back-barrier lagoon facies characterize exposed coastal tracts fa cing the Southern Ocean. In contrast, broad, low-gradient peritidal co mplexes, with a shoaling-upward sequence of subtidal, intertidal, and supratidal mud/sand flat facies, characterize protected shorelines of major gulfs and embayments. A similar upward-shoaling sequence is pres erved in back-barrier lagoons. Along the more tectonically stable part of southern Australia, the last interglacial palaeo shoreline is cons istently recorded at 2 m above present sea level. This is an important regional datum that is significantly below the +6 m level globally at tributed to this sea level highstand. Elsewhere, neotectonic variation s in shoreline elevation are clearly discernible with uplift of up to 18 m associated with Quaternary volcanism near Mount Gambier. The last interglacial strata contain a number of fossils with tropical affinit ies that no longer live in the local waters. The presence of these fos sils is consistent with warmer coastal waters during the last intergla ciation, but does not necessarily imply warmer oceanic waters or a war mer continental climate.