Glacial Lowstand Deposits on the Outer Continental Shelf of Southeastern Australia

Vibracores collected from water depths of 130 to 150 m on the outer continental shelf of southeastern Australia contain evidence for several cycles of shallow marine deposition. One of these vibracores (112/VC/134; lat. 33°24′S, long, 151°58′ E) preserves evidence for the last three glacial lowstands, as inferred from radiocarbon dating, amino acid racemization, and fossil mollusc assemblages. The core contains the inner-shelf molluscs Pecten fumatus, Placamen placidium, and Tawera gallinula, which today live in water depths of 10 to 50 m, in the cool waters of southern Australia. Radiocarbon dating and amino acid racemization analyses on multiple valves of P. fumatus in the core indicate three distinct age groupings of fossil molluscs: (1) those younger than 20,000 yr B.P., (2) those with minimum ages of about 100,000 yr, and (3) those with minimum ages of about 200,000 yr. We assign these sediments to oxygen isotope stages 2, 6, and 8, respectively. The core contains the first shallow-marine lowstand deposits to be recovered from the shelf of eastern Australia. These deposits constrain the last three glacial lowstands on this margin to water depths <130 m below present sea level.