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

主要研究人员将对来自东格陵兰大陆架的高分辨率IMAGES（国际海洋全球变化研究）岩心进行详细研究。最长可达25米的岩芯是在1999年国际IMAGES V巡航的第3和第4阶段，在北欧海域，在国家科学基金会的支持下，从专门的高分辨率地点收集的。Leg 4格陵兰岩心的收集是为了研究冰架从退化到现在的气候和冰川历史。这些地点是从以前收集的地震剖面和较短的重力岩心中选择的。25米高分辨率的岩心在这个地区是前所未有的，可能最多代表了过去的14000年。最初的放射性碳和定年结果以及之前的工作表明，首席研究人员将能够解决十年到一个世纪时间尺度上发生的变化。这些记录将为在广泛的环境条件下观察北极海冰和气候的自然变化提供一个极好的基础。目的是记录东格陵兰洋流的水文情况，包括它的海冰覆盖和淡水流量，以及在三个关键时间间隔内格陵兰冰盖和当地冰川范围的相关变化。他们将采用根据现代海洋学、生物学和沉积学数据校准的多种代用物。代用物包括：底栖和浮游有孔虫的氧碳稳定同位素分析、底栖和浮游有孔虫组合、粒度变化（包括冰山漂流颗粒的定量）、碳和碳酸盐通量变化、硅藻组合和丰度、岩相和古地磁强度记录。主要研究人员将采用采样间隔来提供在关键时期发生的十年到世纪尺度的环境变化的分辨率。这些岩心来自直接受北极海冰影响的陆架地区，沉降速度快，相对海平面波动影响小，为了解北极海冰的自然变率、EGC的性质以及古海洋学、冰川史和古气候的相互作用提供了令人兴奋的前景。

Abstract OPP-0082347The 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.