Reconstructing the Dynamics of Marine-Based East Antarctic Ice Sheet Sectors During Past Warm Periods: Insights from Glaciomarine Sediments

The East Antarctic Ice Sheet (EAIS) is the largest reservoir of frozen freshwater on Earth, with the potential to raise global sea levels by approximately 52.2 meters if fully melted. Despite its critical role in the global climate system, significant uncertainties remain regarding its sensitivity to past and future warming scenarios. Marine-based sectors of the EAIS, such as the Wilkes Subglacial Basin (WSB) and Aurora Subglacial Basin (ASB), are particularly vulnerable to climate-induced instability due to their grounding below sea level. Recent studies have documented mass loss from these sectors during past warm periods (Blackburn et al., 2020), and numerical models predict their substantial contributions to future sea-level rise under warming scenarios (DeConto and Pollard, 2016).

This study aims to reconstruct the behavior of the WSB and ASB during past climatic warm periods using glaciomarine sediments deposited along the continental margins of the Sabrina Coast (draining ASB via Totten Glacier) and the George V Coast (draining WSB via the Mertz, Cook, and Ninnis glaciers). Recovered during IODP Leg 318 and DSDP Leg 28 expeditions, these sediments archive multiple glacial cycles and capture evidence of ice sheet advances and retreats.

Preliminary results focus on characterizing iceberg-rafted debris (IRD) and integrating Nd-Sr isotopic data to infer sediment provenance and ice sheet dynamics. Data reveals that during the Pliocene, shifts in sediment origins were highlighted by significant increases in the accumulation rates of ice-rafted debris. These findings suggest that deglacial warming led to accelerated iceberg calving, followed by the retreat of the ice margin further inland (Bertram et al, 2018).

These findings, combined with available ice core records and numerical ice sheet models, aim to provide a multi-dimensional understanding of EAIS stability under projected warming scenarios. The results will refine predictions of sea-level rise, enhance understanding of glacial-climate interactions, and inform evidence-based strategies for mitigating climate change impacts.