Late Quaternary East Antarctic melting event in the Soya Coast region based on stratigraphy and oxygen isotopic ratio of fossil molluscs

• Main Authors: Miura,Hideki, Maemoku,Hideaki, Seto,Koji, Moriwaki,Kiichi
• Format: Report
• Language: English
• Published: National Institute of Polar Research/Department of Geography, Faculty of Education, Yamaguchi University/Department of Geoscience, Interdisciplinary Faculty of Science and Engineering, Shimane University/National Institute of Polar Research 1998
• Subjects: oxygen isotopic ratio; fossil mollusc; East Antarctic Ice Sheet; Ice melting event; Late Quaternary; Antarctic; East Antarctica; Ongul; Ongul Island; Langhovde; East Ongul Island; Antarc*; Antarctica; Ice Sheet; Polar geoscience
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3033; http://id.nii.ac.jp/1291/00003033/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3033&item_no=1&attribute_id=18&file_no=1

TAMS ^<14>C ages of in situ fossil molluscs (Laternula elliptica) from marine beds of raised beaches in the Soya Coast region, East Antarctica, are divided into two groups late Pleistocene (30-46 ka) in older marine beds and Holocene (3-7 ka) in younger beds The δ^<18>O (PDB) values of 24 fossils in the older marine beds on East Ongul Island and the northern part of Langhovde ranged from about 2 9 to 4 2‰, and those of 27 fossils in the younger beds from about 3 9 to 4 6‰, the variation of the former is wider than that of the latter Relatively lower values of the oxygen isotopic ratio in the Pleistocene fossil compared to the Holocene analogues suggest that relatively more ^<18>O-depleted meltwater was supplied to the sea during the last interstadial than Postglacial age along the northern part of the Soya Coast Some fluvial sediments associated with the meltwater can often be observed under the Holocene marine beds or over the older marine beds The δ^<18>O values of fossils in the upper part of the older beds are higher than those in the lower part on East Ongul Island On the other hand, the time-series variation of oxygen isotopic ratio during the Holocene shells (since 7 ka) does not show such a tendency These facts lead us to the following conclusions (1) the EAIS had possibly retreated from the northern Soya Coast prior to the LGM, (2) there was more meltwater along the northern part of Soya Coast during the last interstadial (30-46ka) than in the Postglacial age, (3) a relatively strong fluvial process probably caused by the ice melting event might have occurred in the Lutzow-Holm Bay region around 30-46 ka