HR: 0800h
AN: PP51A-1331    [Abstracts]
TI: Holocene melting history of Antarctic ice sheet inferred from relative sea-level records around the Lutzow-Holm Bay, Antarctica.
AU: * Okuno, J
EM: okuno@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, Univ. of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032 Japan
AU: Miura, H
EM: miura@nipr.ac.jp
AF: National Institute of Polar Research, 1-9-10 Kaga, Itabashi-ku, Tokyo, 173-8515 Japan
AU: Maemoku, H
EM: maemoku@hiroshima-u.ac.jp
AF: Hiroshima Univ., 1-1-1 Kagamiyama, Higashi-hiroshima, 739-8524 Japan
AB: The relative sea-level record from the last glacial period around the Antarctica is very important to infer the melting history of Antarctic ice sheet, since it is significantly dependent on crustal movements due to rebound after ice retreat. The relative sea-level variations from last glacial maximum around Antarctica are, however, more poorly defined than on any other continents. Recently, Miura et al. (2002) determined the accurate sea-level curve using in situ fossil shells and sequence stratigraphy of raised beach deposits at Skarvsnes, Lutzow-Holm Bay region, East Antarctica, and they deduced that the rapid sea-level falling event which magnitude is about 6 m for about 1000 yrs occurred in the mid-Holocene (4000 - 2700 yrBP). This event is attributed to the rapid removal of a regional ice load as a response to a warmer climatic event, which has been reported as ``mid-Holocene climatic optimum'' from various records around the Antarctica. Then we estimate the melting ice volume around Lutzow-Holm Bay region in the mid-Holocene by comparing the observations and predictions using the glacio-isostatic-adjustment model. In this study, we examine the possibility of the episodic melting of Antarctic ice sheet, and evaluate the spatial distribution, temporal change and volume of the melting ice loads by precise calculations. In our preliminary results, we can??t explain the rapid sea-level falling event unless the regional ice loads of 150 - 200 m melt around the Lutzow-Holm Bay. This result means that the volume of melting ice loads is corresponding to about 1 m for eustatic sea level (ESL) rise. Since previous authors have ascribed about 2 m for ESL to the Holocene Antarctic ice melting on the basis of relative sea-level variations at far-field, so this 1 m ESL rise is equivalent to 30 - 50 percent of the previous Antarctic melting estimate.
DE: 9310 Antarctica
DE: 8162 Rheology--mantle
DE: 1744 Tectonophysics
DE: 1824 Geomorphology (1625)
DE: 1645 Solid Earth
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting