Radiocarbon Profiles and Rapid Climate Change in the Deep North Atlantic: Deep Sea Corals from the Glacial to the Holocene

摘要：在这一奖项下，国际海洋研究所建议使用来自深海珊瑚的U系列和14C测年数据来直接测量过去深海的14C/12C比值(14C)。这应该表明大西洋颠覆环流的强度历史，这是理解气候变化的一个关键因素。国际和平研究所从新英格兰海山采集了一套珊瑚样本，深度范围约为1100-2500米。在收集的样本中，有超过3,700个我们的主要物种克里斯蒂亚氏菌的个体样本，以及超过60公斤的另一个物种Solenosmilia sp.的样本。从前100个U系列的年代来看，很明显，大约30%的收藏涵盖了放射性碳年龄窗口。随着来自一个关键深度区间的许多样品的出现，并跨越大冰川至全新世早期，提议的结果将是来自过去北大西洋的多个14C剖面。此外，在单个珊瑚骨架内进行高分辨率14C年龄采样可以限制深水质量转变的速度和时间。独立的U系列年龄控制允许将这些日期确定的水团重组与任何其他日期确定的气候档案进行比较。将产生两种类型的数据集：年龄相同但深度不同的许多珊瑚的轮廓，以及年龄重叠的相同深度的几个珊瑚的时间序列。这两种类型的.14C重建将与快速气候变化的冰芯记录和包含深层环流速率和碳循环变化信息的大气.14C记录进行比较。根据冰芯(和石笋)的比较，PI将决定快速气候期间深海和大气的分相。

Abstract: Under this award the PI proposes to use coupled U-series and 14C dates from deep-sea corals to directly measure the 14C/12C ratio (14C) of the past deep ocean. This should give an indication of the history of the strength of Atlantic overturning circulation which is a critical element in understanding climate change. The PI has collected a suite of coral samples from the New England Seamounts over a depth range of ~1,100-2,500 meters. In the collection there are over 3,700 individual samples of our main species, D. cristagalli, and over 60 kg of another species, Solenosmilia sp. From the first 100 U-series dates it is clear that about 30% of the collection covers the radiocarbon age window. With many samples from a key depth interval, and spanning the LGM to the early Holocene, the proposal outcome will be multiple profiles of 14C from the past North Atlantic. In addition, high-resolution 14C age sampling within single coral skeletons can constrain the rates and timing of deep-water mass transitions. Independent U-series age control allows these well-dated water mass reorganizations to be compared to any other well dated climate archives. Two types of data sets will be produced; profiles from many corals with the same age but different depths, and time-series from several corals of overlapping age at the same depth. These two types of .14C reconstructions will be compared to ice core records of rapid climate change and records of atmospheric .14C that contain both deep circulation rate and carbon cycle change information. From the ice core (and stalagmite) comparisons the PI will determine the phasing of the deep ocean and the atmosphere during rapid climate.