Stratigraphic information concerning the retreat of the Antarctic ice sheet from the continental shelf after the last glacial maximum is reviewed and compared with new results from a shelf valley off Mac. Robertson Land, East Antarctica. Radiocarbon dates and detailed lithostratigraphic logs indicate that the onset of open marine conditions over shallow shelf banks (<200 m water depth) were achieved prior to 7 000 yr BP and over deep (~1 000m) middle to outer shelf valleys open marine conditions were achieved prior to 5,400 yr BP. Radiocarbon dating of bulk-organic carbon in some diatom oozes by the AMS method demonstrates problems of contamination. Jurassic pollen, spores and organic matter has been eroded and incorporated into Holocene diatom ooze, causing anomalously old 14C dates (eg. one surface age of 7 084 ±86 yr BP was determined). This problem may arise at other locations around East Antarctica where older strata outcrop on the seafloor.