Age and Isotopic Characterization of Ice-Rafted Sand Grains in the North Atlantic

9633554 Broecker Climatic cooling enhances the deposition of ice rafted detritus (IRD) every 1000 to 2000 years. Several such dampened events can be found in the Holocene that thus something other than ice sheets may be modulating these events. The PIs plan to target 3 layers, the Younger Dryas, and H3 and H6 Heinrich events for special focus. Multiple tools will be used to determine the likely sources for IRD, including grain size, stable isotopic analysis, and composition of Pb isotopes in feldspar grains and Ar/Ar in hornblende to determine the provenance. Samples from the Hudson Straits, Gulf of St. Lawrence, Denmark Straits and East Greenland current areas may help identify the sources from Greenland, Scandinavia, etc.