Rapid changes in surface and deep water conditions at the Faeroe Margin during the last 58,000 years
Rapid changes in surface and deep water conditions at the Faeroe Margin during the last 58,000 years
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过去 58,000 年来法罗群岛边缘地表和深水状况的快速变化
DOI：
10.1029/96pa02618
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
L. Labeyrie
中科院分区：
文献类型：
--
作者：
T. L. Rasmussen;E. Thomsen;T. V. Weering;L. Labeyrie
一个高分辨率的活塞芯，ENAM 93 -21，从附近的法罗群岛海峡附近的水深1020米的磁化率，表面氧同位素，粒度分布，冰筏碎屑（IRD）的内容，和分布的南极和底栖有孔虫的变化进行了研究。覆盖过去58，000年的核心与格陵兰冰芯相关，并与来自挪威海和北大西洋的古记录进行比较。从格陵兰冰芯的调查时间段中识别出的所有15个Dansgaard-Oeschger气候循环都已在ENAM 93 -21芯中确定。每个周期根据特征性底栖和浮游动物群被细分为三个间隔。间的间隔包含一个相对温暖的南极动物区系和底栖动物区系类似于现代动物在挪威海。这表明目前的温盐对流，深水对北大西洋深水（NADW）有重大贡献。过渡冷却间隔的特点是更多的冷水浮游有孔虫和冰相关的底栖物种。底栖动物表明底层水条件有限，对NADW的贡献减少。N.厚皮病最冷的地表水条件出现在视距间隔。底栖动物以与大西洋中层水有联系的物种为主，这表明大西洋对挪威海的影响有所增加，而且可能没有通过法罗群岛-设得兰海峡对北大西洋平均水深作出贡献。这三种不同的环流模式可以与在挪威海和北大西洋的古海洋事件。
A high-resolution piston core, ENAM93-21, from a water depth of 1020 m near the Faeroe-Shetland Channel is investigated for variations in magnetic susceptibility, surface oxygen isotopes, grain size distribution, content of ice-rafted detritus (IRD), and distribution of planktonic and benthic foraminifera. The core, covering the last 58,000 years, is correlated with the Greenland ice cores and compared with paleorecords from the Norwegian Sea and the North Atlantic Ocean. All fifteen Dansgaard-Oeschger climatic cycles recognized from the investigated time period in the Greenland ice cores have been identified in the ENAM93-21 core. Each cycle is subdivided into three intervals on the basis of characteristic benthic and planktonic faunas. Interstadial intervals contain a relatively warm planktonic fauna and a benthic fauna similar to the modern fauna in the Norwegian Sea. This indicates thermohaline convection as at present, with a significant contribution of deep water to the North Atlantic Deep Water (NADW). Transitional cooling intervals are characterized by more cold water planktonic foraminfera and ice-related benthic species. The benthic fauna signifies restricted bottom water conditions and a reduced contribution to the NADW. The peak abundance of N. pachyderma (s.) and the coldest surface water conditions are found in the stadial intervals. The benthic fauna is dominated by species with an association to Atlantic Intermediate Water, suggesting an increased Atlantic influence in the Norwegian Sea, and there was probably no contribution to the NADW through the Faeroe-Shetland Channel. The three different modes of circulation can be correlated to paleoceanographic events in the Norwegian Sea and the North Atlantic Ocean.