ICE-RAFTED DEBRIS IN THE NORTH ATLANTIC DURING THE PLEISTOCENE (~1.4-1.7 MA): INTEGRATED OCEAN DRILLING PROGRAM (IODP) EXPEDITION 306, SITE U1314

During IODP Expedition 306 cores of sediment were obtained for the purpose constructing the paleoceanographic history and climatic variance in the North Atlantic. Sediment for this research came from Site U1314, which is located southeast of Greenland and south of Iceland on the southern part of the Gardar Drift. Site U1314 is just north of the classic IRD (Ice-Rafted Debris) belt.

Samples used in this study were obtained from the IODP Bremen Core Repository. Approximately 10 cc of sediment was collected for each sample at a resolution of one sample every 1500-2000 years. The focus of the research was to collect and analyze all coarse-grained sediment. To obtain this particular size sediment the samples were weighed, dried, wet sieved at 150µm and 2mm, dried and weighed once more. The >150 ìm size-fraction defines IRD for this study.

Careful examination of the samples under a binocular microscope shows that the IRD is composed of quartz (including rose quartz), basalt, felsic igneous, obsidian, sandstone, and schist. These compositional variations for the IRD allow provenance to be determined. Mass accumulation rates (MARs) were calculated for the IRD in order to more accurately quantify the IRD input when compared with the biogenic (dominantly foraminifera) input. From the IRD data, in addition to shipboard lightness and magnetic susceptibility data, climate patterns (i.e., glacial pulses), and thus the paleoclimate history near the Gardar Drift is determined for the interval 1.4-1.7 Ma.