HR: 14:20h
AN: PP53B-03 INVITED    [Abstracts]
TI: Searching for Eustasy in Deglacial Sea Level Histories
AU: * Mitrovica, J X
EM: jxm@physics.utoronto.ca
AF: Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S1A7, Canada
AU: Milne, G A
EM: g.a.milne@durham.ac.uk
AF: Department of Earth Sciences, Durham University, Science Labs, Durham, DH1 3LE, United Kingdom
AU: Latychev, K
EM: latychev@physics.utoronto.ca
AF: Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S1A7, Canada
AB: Relative sea-level (RSL) histories over the last glacial cycle may be decomposed into a eustatic (i.e., globally uniform) term and a far more complex signal associated with glacial isostatic adjustment (GIA). The spatial and temporal complexity of the latter arises from deformational and gravitational perturbations driven by the surface mass (ice plus ocean) redistribution. Any attempt to accurately estimate excess ice volume since the LGM reduces to an effort to isolate the eustatic signal, either by choosing to analyze RSL records at a geographic site where GIA effects are thought to be small or where these effects can be removed using numerical models of post-glacial sea-level change. In this talk we present a large suite of global, deglacial sea-level predictions generated by varying parameters defining both the Late Pleistocene ice history and viscoelastic Earth model. Our calculations are based on a new generation of post-glacial sea-level algorithms that take accurate account of shoreline migration processes and Earth rotation, as well as 3-D Earth structure. We use the model predictions to generate global maps of the mean departure of the sea-level histories from the eustatic signal and a standard deviation that reflects reasonable uncertainties in the input (ice, Earth) parameters. Our results demonstrate that there are relatively few locations where: (I) the total predicted RSL change closely tracks the eustatic value; and (II) the GIA component of the signal is insensitive to reasonable variations in the input parameters (and so can be accurately removed from the observations). The maps will be a useful tool for field scientists in choosing suitable sites for future data acquisition.
DE: 0726 Ice sheets
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
DE: 4926 Glacial
DE: 8162 Rheology: mantle (8033)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting