15384±578 cal. yr BP), Hudson (between 7707±185 and 7795±131 cal. yr BP) and Aguilera (<3596±230 cal. yr BP) volcanoes also occur in some of the cores as indicated by the characteristic compositions of their tephra glass, which differ both from each other and also from that of tephra derived from Mount Burney. Significant loss of alkali elements during alteration of the volcanic glass in the tephra layers was observed, especially within acid peat soils, and this may be an important factor in the plant nutrient supply.]]>

Abstract. Five gravity cores taken from the Reykjanes Ridge have been used to establish a link between sediment physical properties and atmospheric records documented by 5•aO variations in Greenland ice cores over the last 45,000 calendar years. Marine Gamma Ray Attenuation Porosity Evaluator density and magnetic susceptibility variations could be linked with the ice core Dansgaard-Oeschger and Bond cycles. This is supportedby ice-rafted detrl'tUs (IRD), grain size, the quartz/feldspar ratio, and carbonate, isotopic, and f6raminiferal records. The covariation of the sediment physical properties and •5•aO in Greenland ice indicates a coupling of atmospheric temperature and paleocirculation variations. Gradual reduced bottom currents (Iceland-Scotland Overflow Water) and enhanced iceberg discharges have been reconstructe. d fo.r cold atmospheric periods relative to interstadial times. In. the study area_the magnetic susceptibility signal is not relatecl to the ice-rafted detritus input but most probably reflects the variations oI-the IceIand-Scotland Overflow Water intensity transporting titanomagnetlte into the R(,•ykjanes Ridge region.

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Some close-up core photographs have been tonally enhanced to better illustrate particular features of interest.Cover photograph shows the Oden (left), Sovetskiy Soyuz (middle), and drilling vessel Vidar Viking (right) on location in the Arctic sea ice. Photograph by Jens Matthiessen. The Integrated Ocean Drilling Program (IODP) is the most ambitious ocean exploration and drilling program ever undertaken. With multiple platforms and multiple partners, our research spans the globe and truly represents international collaboration and diplomacy among scientists and nations interested in attaining scientific goals. ISSNThe Proceedings present the scientific and engineering results of IODP drilling projects, each an important component of an international program designed to better understand Earth, its environmental changes and processes, the deep biosphere, and climate change.The collective effort required to conduct each IODP expedition is colossal. Beginning with scientists who submit ocean drilling research proposals, there are others who evaluate, rank, and prioritize proposals. Scientists also schedule the science operations, select science party members from scores of international scientists qualified to participate, plan platform operations, ready the drillship, and choose borehole locations. There are onboard logistics to manage and critical communications to coordinate among various academic institutions, governments, and national science organizations. And the resulting data must be managed and made accessible to scientists, particularly those who will prepare future proposals. Every aspect of planning an IODP expedition takes a village-or several. There are many participants and many more stakeholders.

Marine records from the Reykjanes Ridge indicate ice sheet variations and abrupt climate changes. One of these records, ice-rafted detritus (IRD), serves as a proxy for iceberg discharges that probably indicates ice sheet fluctuations. The IRD records suggest that iceberg discharge 68,000–10,000 yr B.P. happened more frequently than the 7000- to 10,000-yr spacing of the Heinrich events. An IRD peak 67,000 to 63,000 yr B.P. further suggests that the Middle Weichselian glaciation started about 12,000 yr earlier in the North Atlantic than in the Norwegian Sea. Several later IRD events, in contrast, correlate with Norwegian Sea IRD-rich layers and imply coeval ice sheet advances in the North Atlantic and the Norwegian Sea. Coccoliths in a core from the Reykjanes Ridge show distinct peaks in species that record occasional inflow of warm surface water during the last glaciation, as previously reported from the eastern Labrador Sea. High abundances of coccoliths, together with a decrease of Neogloboquadrina pachyderma sin. and relatively low δ18O values, imply enhanced advection of the North Atlantic Current 69,000–67,000 yr B.P., 56,000–54,000 yr B.P., 35,000–33,000 yr B.P., and 26,000–23,000 yr B.P. This advection provided a regional moisture source for extension of ice sheets onto the shelf. In contrast, most of the IRD events are characterized by cold polar surface water masses indicating rapid variations in ocean surface conditions.