IRD flux and supporting data on two cores in the western North Atlantic

A series of catastrophic iceberg discharges termed Heinrich events punctuated the last ice age in the North Atlantic. During Heinrich events, coarse terrigenous debris released from the drifting icebergs and preserved in deep-sea sediments serves as an indicator of their passage. Quantifying the vertical flux of ice-rafted debris (IRD) in pelagic sediments can resolve questions regarding the timing and variation in ice sheet calving intensity. In this study, 230Thxs-based IRD flux was measured throughout the last glacial period in a deep-sea sediment core from the western North Atlantic (EW9303-37JPC, 43.68°N, 46.28°W, 3981 m), and complemented during Marine Isotope Stages (MIS) 1-3 by measurements from DY081-GVY01 (50.16°N, 45.51°W, 3721m) in the Labrador Sea. The cores are downstream from the Hudson Strait, a leading candidate for the conduit of the icebergs from the Laurentide ice sheet (LIS). We compare our results with the directly equivalent existing data in the eastern North Atlantic, and show that EW37JPC and DY001GVY have higher IRD fluxes during all Heinrich events, notably including 3 and 6. This study demonstrates that the Laurentide played a role in all Heinrich events and raises the likelihood that a single mechanism can account for their genesis.