Characterizing West Antarctic Ice Sheet Dynamics during Marine Isotope Stage 5 using Analysis of Iceberg Rafted Debris

Description

Past periods of climate warming provide valuable analogues for understanding how the West Antarctic Ice Sheet (WAIS) may respond to ongoing climate change and its potential contribution to sea-level rise. Because the WAIS is highly vulnerable to ocean-driven melting, identifying the conditions that led to past ice-sheet retreat is critical for improving projections of future changes. This study investigates the relationship between ocean warming, iceberg melting, and environmental change by comparing marine sediment records from IODP Site U1533, in the Amundsen Sea near Thwaites Glacier, and ODP Site 1101, west of the Antarctic Peninsula. Iceberg-rafted debris (IRD) was used as a proxy for iceberg discharge and ice-sheet instability, Ba/Rb ratios were used to reconstruct changes in marine productivity associated with warmer interglacial conditions, and magnetic susceptibility measurements were analyzed to identify variations in sediment composition associated with changes in depositional processes. Focusing on Marine Isotope Stage 5 (MIS 5) and comparing multiple interglacial intervals, we evaluate how these proxy records respond to ocean warming. Pronounced IRD peaks occur at the onset and termination of interglacial periods, indicating increased iceberg melting. Ba/Rb ratios also increase during interglacial intervals, consistent with enhanced marine productivity under warmer ocean conditions. These results suggest that the WAIS responds rapidly to relatively modest ocean warming and that periods of climate transition represent an increase in ice-sheet instability. This work improves our understanding of WAIS sensitivity to ocean warming and provides insights for predicting future Antarctic contributions to global sea-level rise.

Institutions

• University of South Florida St. Petersburg

  Florida, St. Petersburg
• Eckerd College

  Florida, St. Petersburg

Categories

Funders

• U.S. National Science Foundation

  Government of the United States of America

  Virginia, Alexandria

  Grant ID: OCE-2244285

Licence