Correlation of Ice-Rafted Detritus in South Atlantic Sediments with Climate Proxies in Polar Ice over the Last Glacial Period

Abstract

Previous study identified 6–7 millennial-scale episodes of South Atlantic ice-rafted sediment deposition (SA events) during the glaciation. Questions remain, however, regarding their origin, significance for sea-ice and/or Antarctic ice-sheet dynamics, and relationship to climate. Here I correlate sediment core (TTN057–21) SA events to Greenland and Antarctic ice using two independent methods, stable isotopes and geomagnetic paleointensity, placing SA events in the context of polar climate change in both hemispheres. Marine isotopic stage (MIS) 3 SA events generally coincided with Greenland interstadials and with cooling following Antarctic warm events (A1-A4). This anti-phase behavior is best illustrated when SA0 coincided with both the Antarctic Cold Reversal and Bolling-Allerod warming in Greenland. Moreover, SA events coincide with sea-level rises during the deglaciation (mwp1A) and MIS 3 (30.4, 38.3, 43.7, 51.5 ka), implying unpinning of grounded Weddell Sea region ice masses discharged debris-laden bergs that had a chilling effect on South Atlantic surface temperatures.