HR: 08:45h
AN: C11B-04    [Abstracts]
TI: Modelling Near-Field Antarctic Sea-Level Data to Explore the Possibility of a Dominant Antarctic Contribution to Meltwater Pulse IA.
AU: * Bassett, S E
EM: s.e.bassett@dur.ac.uk
AF: Department of Earth Sciences University of Durham, Science Labs South Road, Durham, DH1 3LE United Kingdom
AU: Milne, G A
EM: g.a.milne@dur.ac.uk
AF: Department of Earth Sciences University of Durham, Science Labs South Road, Durham, DH1 3LE United Kingdom
AU: Bentley, M J
EM: M.J.Bentley@dur.ac.uk
AF: Department of Geography University of Durham, Science Labs South Road, Durham, DH1 3LE United Kingdom
AU: Huybrechts, P
EM: phuybrechts@awi-bremerhaven.de
AF: Alfred-Wegener-Institute, Am Handelshafen 12, Bremerhaven, 27570 Germany
AB: Sea-level data obtained from Barbados and Sunda Shelf show a rapid rise in global sea level of ~ 20 m between 14.5 and 13.5 kyr BP (meltwater pulse IA or mwp-IA). The relative contributions from major ice sheets to mwp-IA are not well known and the effect of such an event on the climate system would vary dramatically for different melt source scenarios [e.g. Weaver et al., Science 299, 5613, 2003; Clark et al., Paleoceanography 11, 5, 1996]. Recent far-field sea-level modelling studies have suggested a dominant Antarctic contribution to MWP-IA [Clark et al., Science 295, 2438 2002; Bassett et al., Science 309, 5736]. Work on sea-level and climate modelling as well as investigations into the oxygen isotope record have suggested the optimum contribution from the Antarctic to be ~ 15 m of eustatic equivalent sea-level [Bassett et al., Science 309, 5736; Weaver et al., Science 299, 5613, 2003; Rohling et al., Nature, 430, 7003, 2004]. Results from glaciological, glacio-isostatic and geological studies suggest, however, that the Antarctic ice sheet may have contributed only 12-20 m of total eustatic equivalent sea-level from the last glacial maximum to present day, with much of this melt occurring during the Holocene period [e.g. Huybrechts, Quaternary Science Reviews, 21, 1-3, 2002; Bentley, Quaternary Science Reviews, 18, 14, 1999; Denton and Hughes, Quaternary Science Reviews, 21, 1-3, 2002; Nakada et al., Marine Geology, 167, 2000; Ivins et al. XVIII SCAR Meeting, 2005]. We have performed a modelling analysis of sea-level observations from the Antarctic continent to further test the plausibility of a dominant Antarctic contribution to mwp-IA and examine the apparent discrepancy between the studies outlined above. We modified the loading history from a 3D, thermomechanical ice sheet model to explore a variety of different Antarctic melt source geometries in order to: (1) determine whether the near-field sea-level observations are consistent with a significant Antarctic contribution to mwp-IA, and (2) determine the primary source components of this meltwater within the Antarctic ice complex. Our results indicate that the near-field sea-level observations are consistent with a large and rapid melt of the Antarctic ice sheet around 14 cal. kyr BP and therefore support the conclusion of a large Antarctic contribution to the mwp-IA event.
DE: 0726 Ice sheets
DE: 0798 Modeling
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
SC: Cryosphere [C]
MN: Fall Meeting 2005