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The Coorong Coastal Plain in southeastern South Australia preserves a long Quaternary record of cool-water, temperate-carbonate sedimentation in the form of high wave energy, barrier shoreline deposits and associated back-barrier lagoon facies that formed during successive sea-level highstands. Whole-rock samples of bioclastic skeletal carbonate sand with subordinate quartz were collected from aeolian facies (modern and relict foredunes) of a Holocene embayment fill and from ten Pleistocene barriers across the coastal plain in a transect from Robe to Naracoorte. The extent of leucine racemization (total acid hydrolysate and free amino acids) in the Pleistocene skeletal carbonate sand (63–500 μm) increases monotonically with age and is consistently higher than for entire fossil molluscs from the same allostratigraphic units, reflecting the lengthy residence time for bioclasts in this high wave energy …