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GSA Connects 2021 in Portland, Oregon

Paper No. 139-4
Presentation Time: 8:50 AM

RAPID POSTGLACIAL REBOUND AMPLIFIES GLOBAL SEA-LEVEL RISE FOLLOWING WEST ANTARCTIC ICE SHEET COLLAPSE


PAN, Linda1, POWELL, Evelyn M.1, LATYCHEV, Konstantin2, MITROVICA, Jerry X.1, CREVELING, Jessica3, GOMEZ, Natalya4, HOGGARD, Mark J.5 and CLARK, Peter U.3, (1)Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, (2)Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138; Lamont-Doherty Earth Observatory, Columbia University, 61 Rte 9W, Palisades, NY 10964, (3)College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 101 SW 26th Street, Corvallis, OR 97331, (4)Earth and Planetary Sciences Department, McGill University, 3450 University St., Montreal, QC H3A 0E8, Canada, (5)Lamont-Doherty Earth Observatory, Columbia University, 61 Rte 9W, Palisades, NY 10964; Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138; Research School of Earth Sciences, Australian National University, 142 Mills Rd, Canberra, ACT 0200, Australia

Studies of peak global mean sea level (GMSL) during the Last Interglacial (LIG; 130-116 ka) commonly cite values ranging from ~2-5 m for the maximum contribution from grounded, marine-based sectors of the West Antarctic Ice Sheet (WAIS). This estimate does not include postglacial rebound and the associated meltwater flux out of marine sectors as they become exposed by retreating ice, a contribution typically considered to be small and slowly accumulating. However, geodetic, seismic and geological evidence indicate that West Antarctica is underlain by low-viscosity shallow mantle, and thus the assumption that the contribution to GMSL from the outflux mechanism is negligible should be revisited. We incorporate both the outflux mechanism and complex 3-D viscoelastic mantle structure in new sea-level predictions and find that the water outflux mechanism contributes ~1 m of additional GMSL change within ~1 kyr of WAIS collapse. This conclusion has important implications for the sea-level budget not only during the LIG, but also during all previous interglacials. Finally, we discuss the importance of including this mechanism in analyses of site-specific sea-level indicators, as well as the inaccuracies that are introduced by the common assumption that the Earth’s viscoelastic structure varies with depth alone.
Recorded Presentation Recorded Presentation

Session No. 139

T71. Advances and New Voices in Marine and Coastal Geoscience I
Tuesday, 12 October 2021: 8:00 AM-12:00 PM
D136 (Hybrid Room) (Oregon Convention Center)
Geological Society of America Abstracts with Programs. Vol 53, No. 6
doi: 10.1130/abs/2021AM-368205
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