Ice-Ocean-Atmosphere Interactions Along the East Greenland Margin on Decade to Century Timescales Over the Last 14 ka

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Abstract OPP-0082347 The Principal Investigators will conduct a detailed study of high resolution IMAGES (International Marine Global Change Study) cores from the East Greenland continental shelf. Cores up to 25 m long were collected from specially targeted, high-resolution sites with support from a an NSF grant their partnership in the 1999 international IMAGES V cruise, Legs 3 and 4 in the Nordic Seas. The Leg 4 Greenland cores were collected for study of climate and glacial history of the shelf from degradation to the present. The sites were selected from seismic profiles and shorter gravity cores collected on previous. The 25 meter, high resolution cores are unprecedented in this are and likely represent at most the last 14,000 years. Initial radiocarbon and dating results and previous work indicate that the Principal Investigators will be able to resolve changes occurring on decade-to-century time scales. These records will provide an excellent basis for looking at the natural variability of sea ice and climate in the Arctic under a wide range of environmental conditions. The goal is to document the hydrography of the East Greenland Current, including its sea-ice cover and freshwater flux, and associated changes in the extent of the Greenland Ice Sheet and local glaciers during three critical time intervals. They will employ multiple proxies that have been calibrated to modem oceanographic, biological and sedimentological data. The proxies include: oxygen and carbon stable isotope analysis of benthic and planktonic foraminifers, benthic and planktic foraminiferal assemblages, grain-size changes (including quantification of iceberg rafted grains), carbon and carbonate flux changes, diatom assemblages and abundances lithofacies and paleomagnetic intensity records. The Principal Investigators will employ sampling intervals to provide decade to-century scale resolution of the environmental changes that have occurred through the critical time periods. These cores from a shelf area directly influenced by the arctic sea ice, rapid sedimentation rates and little influence of relative sea-level fluctuations offer exciting prospects for understanding natural variability in the Arctic sea ice, in the properties of the EGC, and in the interplay of paleoceanography, glacial history and paleoclimate.