Centennial- to millennial-scale ice-ocean interactions in the subpolar northeast Atlantic 18-41 kyr ago
Centennial- to millennial-scale ice-ocean interactions in the subpolar northeast Atlantic 18-41 kyr ago
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18-41年前亚极地东北大西洋发生百年至千年规模的冰海相互作用
DOI：
10.1029/2010pa002084
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
S. Hemming
中科院分区：
文献类型：
--
作者：
I. Hall;E. Colmenero;R. Zahn;V. Peck;S. Hemming
为了监测英国-爱尔兰冰盖（BIIS）在海洋同位素阶段（MIS） 2和3的演变及其对海洋表面结构的影响，我们分析了MD04-2829CQ（东北大西洋北罗克尔海槽Rosemary Bank）岩心沉积物的年代为~ 41 ~ ~ 18 ka B.P.的浮冰碎屑通量和组成、单个角闪石颗粒的40Ar/39Ar年龄、多物种浮游稳定同位素记录。浮游有孔虫组合数据和基于动物群的海面温度（SSTs）表明，该地区BIIS动力学与海洋表面结构和水性质之间存在密切的相互作用。核心位置位于北大西洋洋流（NAC）下方，是监测相关海洋锋面位置变化的理想地点，可以记录动物的变化。这些数据揭示了一系列biis来源的冰山裂冰事件，这些事件与低海温有关，通常与浮游有孔虫组合的剧烈变化同步，并与Neogloboquadrina pachyderma （sinisstral coiling）和Globigerina bulloides分类群的稳定同位素记录的变化同步。产犊事件的节奏，从典型的MIS 3晚期的Dansgaard-Oeschger千禧年时间尺度到从~ 28 ka b.p.的多世纪周期，代表了BIIS的建立及其向Heinrich事件（HE） 2和末次盛冰期增长的不稳定性。我们的数据证实了BIIS的不稳定性与邻近东北大西洋地表水的温度和盐度之间的强耦合，并证明了BIIS改变NAC流向北欧海的能力。相比之下，地下水体质量受到的影响较小，除了在格陵兰岛含有he的冰期，当最强烈的水柱重组与来自劳伦泰德冰盖的米色碳酸盐沉积同时发生时。
In order to monitor the evolution of the British-Irish Ice Sheet (BIIS) and its influence in surface ocean structure during marine isotopic stages (MIS) 2 and 3, we have analyzed the sediments recovered in core MD04-2829CQ (Rosemary Bank, north Rockall Trough, northeast Atlantic) dated between ∼41 and ∼18 ka B.P. Ice-rafted debris flux and composition, 40Ar/39Ar ages of individual hornblende grains, multispecies planktonic stable isotope records, planktonic foraminifera assemblage data and faunal-based sea surface temperatures (SSTs) demonstrate a close interaction between BIIS dynamics and surface ocean structure and water properties in this region. The core location lies beneath the North Atlantic Current (NAC) and is ideal for monitoring the shifts in the position of its associated oceanic fronts, as recorded by faunal changes. These data reveal a succession of BIIS-sourced iceberg calving events related to low SST, usually synchronous with dramatic changes in the composition of the planktonic foraminifera assemblage and with variations in the stable isotope records of the taxa Neogloboquadrina pachyderma (sinistral coiling) and Globigerina bulloides. The pacing of the calving events, from typically Dansgaard-Oeschger millennial timescales during late MIS 3 to multicentennial cyclicity from ∼28 ka B.P., represents the build-up of the BIIS and its growing instability toward Heinrich Event (HE) 2 and the Last Glacial Maximum. Our data confirm the strong coupling between BIIS instabilities and the temperature and salinity of surface waters in the adjacent northeast Atlantic and demonstrate the BIIS's ability to modify the NAC on its flow toward the Nordic Seas. In contrast, subsurface water masses were less affected except during the Greenland stadials that contain HEs, when most intense water column reorganizations occurred simultaneously with the deposition of cream-colored carbonate sourced from the Laurentide Ice Sheet.