80-2 Reconstructing Antarctic Ice Sheet deglaciation from integrated marine and terrestrial datasets

Session: Recent Advances in Glacial Geology, Geomorphology, and Chronology

Presenting Author:

Authors:

Abstract:

The growing acquisition of geologic datasets over the last few decades has significantly improved our understanding of Antarctic deglaciation, but each type of data is spatially and temporally limited. Marine geomorphology, sedimentology, and radiocarbon data can be used to reconstruct past ice-sheet margin evolution as the ice sheet receded across the continental shelf, while cosmogenic-nuclide concentrations at exposed rock outcrops reveal terrestrial ice thinning patterns. Historically, though, marine- versus terrestrial-based studies have generated divergent narratives on the last deglaciation: exposure ages indicate terrestrial deflation thousands of years after the marine grounding line had already receded across the continental shelf. This disconnect between marine and terrestrial archives has hindered the creation of a single, data‑consistent story of Antarctic deglaciation.

To comprehensively reconstruct the deglacial evolution of the Antarctic ice sheet, these discrete snapshots of geologic information about marine and terrestrial ice sheet change must be integrated to reflect the behavior of the whole. Here we use numerical ice sheet modeling that physically links changes in ice sheet margin position (i.e., marine grounding line retreat) with changes in ice thickness (i.e., terrestrial ice surface deflation). Specifically, we align marine and terrestrial datasets using a common metric: model-data timing mismatch. We also apply these model-data comparison techniques to find internally consistent ice sheet change histories that match the sparse geologic data across both marine and terrestrial environments. Used together, models and data can provide a robust and physically based reconstruction of glacial evolution.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8454

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