Fluctuation of Antarctic Ice Sheet and environmental change during the late Quaternary

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1.The investigate on ESR dating of in situ fossil aragonitic shells from raised beaches in the Lutzow-Holm Bay region to compare ESR ages with ^<14>C dates and to discuss on late Pleistocene chronology. From the ESR ages, the ^<14>C ages (33 -43 ka) seem to be underestimated and to be much closer to the marine isotope stage (MIS) 4-5 or MIS 6-7 rather than to MIS 3.2.Amino acid chronology was applied also for the same samples of molluscan shell. Amino acid ages range from 212 ka to 414 ka, if they have been experienced constant condition of -10ーC. These ages are the oldest age among ^<14>C age, ESR age and amino acid age.3.Glacial erratics as well as bedrock samples from Mt.Riiser-Larsen were collected for Cosmogenic Radio Nuclides (CRN) dating. The results of the CRN dating are approximately 50ka that is consistent with the TL and radiocarbon age results from the lake sediments in the coastal site. The lowest glacial erratics recovered from 290m in altitude show the minimum CRN age of 24ka indicating the timing of the final melting of the ice sheet in this area. Given that the trimline at the Mt.Riiser-Larsen indicates the maximum height of the most recent episode of expansion of the ice sheet, EAIS in this area experienced 2 distinct events of retreat since about 50ka to the Holocene.