Collaborative Research: Origin, Timing, and Significance of Millennial-Scale Ice-Rafted Detritus (IRD) Events in the Southern Ocean during the last Ice Age

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AbstractUnder this award the PIs will study ice-rafted detritus (IRD) in high-sedimentation-rate cores from the high-latitude South Atlantic (SA). Previos studies have identified six to seven discrete episodes of IRD deposition between 12 and 60 kyr during the last glaciation that have been suggested to be regionally correlative. If these events can be shown to be widely distributed and synchronous, they may indicate instability in Antarctic ice sheets. The PIs will examine the origin of these South Atlantic IRD (SA-IRD) events, their significance for Antarctic ice-sheet dynamics, and their exact relationship to millennial-scale climate events recorded in polar ice cores. This project will 1.) map the aerial distribution of IRD events in the South Atlantic basin; 2.) date SA-IRD events using AMS-14C and estimating particle flux and sediment redistribution using the Th-normalization method; 3.) trace the origin of IRD events to their Antarctic source area(s) using mineralogy and geochemistry; and 4.) correlate South Atlantic IRD events to Antarctic and Greenland ice cores, other marine sediment cores (e.g., North Atlantic), and global sea level records.