AMINOSTRATIGRAPHY OF QUATERNARY COASTAL SEQUENCES IN SOUTHERN AUSTRALIA - AN OVERVIEW

Since the early 1980s, amino acid racemisation reactions have been app lied to the dating of Quaternary coastal deposits in Australia. Sequen ces of Middle Pleistocene age or younger have received the greatest at tention. Amino acid racemisation has been applied as a relative and nu meric dating method, as well as for identifying remanie fossils and in delineating the spatial distribution of some fossil mollusc species. The method has also been used to verify the radiocarbon ages of fossil molluscs from interstadial sediments. It has also been used in studie s of coastal neotectonics and in comparisons with other dating methods (e.g. electron spin resonance and thermoluminescence). The most relia ble results are from replicate analyses of the hinge region of well-pr eserved and diagenetically unmodified fossil bivalve molluscs from dee ply buried situations (i.e. > 1 m). Molluscs have been dated from a ra nge of sites around the southern Australian coastline and include spec imens of Plio-Pleistocene age, and from Middle Pleistocene (Oxygen Iso tope Stage 7; ca. 220 ka BP), Late Pleistocene (Substage 5e; ca. 125 k a BP), interstadial (Stage 3; 45 to 30 ka BP), last glacial (Stage 2; ca. 18 ka BP) and Holocene sequences. Amino acid racemisation dating o f the Australian Quaternary coastal record has: (1) confirmed the wide spread occurrence of last interglacial coastal strata and allowed thei r correlation with sequences of equivalent age from the northern hemis phere; (2) identified strata of penultimate interglacial age; and (3) confirmed the interstadial age of marine strata (Stage 3) in Gulf St V incent, South Australia. Aminostratigraphic studies of the southern Au stralian Quaternary coastal record also indicate that sea-levels durin g the penultimate interglacial (Stage 7) may have been higher than oth erwise predicted on the basis of the oxygen isotope record.