Evidence for regional cooling, frontal advances, and East Greenland Ice Sheet changes during the demise of the last interglacial
Evidence for regional cooling, frontal advances, and East Greenland Ice Sheet changes during the demise of the last interglacial
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DOI：
10.1016/j.quascirev.2016.08.029
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发表时间：
2016-10
影响因子：
4
通讯作者：
Nil Irvalı;U. Ninnemann;H. F. Kleiven;E. Galaasen;Audrey Morley;Y. Rosenthal
中科院分区：
文献类型：
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作者：
Nil Irvalı;U. Ninnemann;H. F. Kleiven;E. Galaasen;Audrey Morley;Y. Rosenthal
利用高分辨率岩样和海面气候记录描绘了北大西洋气候、水文和格陵兰冰盖（GIS）活动从海洋同位素阶段（MIS） 5e高峰到末次冰期开始的过程。我们使用了在格陵兰岛南部回收的Eirik Drift沉积物MD03-2664(57°26.34'N, 48°36.35'W)，用于监测地理信息系统范围的波动和冰山崩解事件。我们的研究结果表明，在MIS 5e早期存在大量的冰筏碎片（IRD），直到122kyr BP由于GIS的减弱而逐渐减少。北亚极环流海表温度（SSTs）在MIS 5e早期达到峰值，与日照峰值一致。区域变冷导致最后一次间冰期的消亡，开始于MIS 5e底栖δ18O高原结束之前，大约在119 kyr BP，当时夏季日晒减弱。这一逐渐冷却趋势在约117 kyr BP被一个突然和短暂的冷却事件打断。在117 kyr BP降温事件期间，IRD丰度的增加表明，区域冰盖生长发生在MIS 5e底栖生物δ18O高原结束和主要冰川开始之前。格陵兰岛南部的海温在冰期开始时经历了两步冷却，这与北大西洋和欧洲大部分地区观测到的模式相似。底栖生物δ18O的增加是平行的，这表明这两步冷却与北半球冰川作用的两阶段强化有关。
High-resolution lithic and sea surface climate records are used to portray the progression of North Atlantic climate, hydrography, and Greenland Ice Sheet (GIS) activity through the peak of Marine Isotope Stage (MIS) 5e into the last glacial inception. We use Eirik Drift sediment core MD03-2664 (57°26.34′N, 48°36.35′W), recovered south of Greenland, strategically located to monitor fluctuations in GIS extent and iceberg calving events. Our results show that a significant amount of ice-rafted debris (IRD) was present during the early MIS 5e, until gradually tapering off by 122 kyr BP due to a diminishing GIS. Sea surface temperatures (SSTs) in the northern subpolar gyre reached peak values early in MIS 5e coinciding with peak insolation. Regional cooling leading to the demise of the last interglacial started prior to the end of the MIS 5e benthic δ18O plateau, at approximately 119 kyr BP, as summer insolation waned. This gradual cooling trend is interrupted by an abrupt and brief cooling episode at ∼117 kyr BP. Increased IRD abundance during the 117 kyr BP cooling event suggests that regional ice sheet growth occurred prior to the end of the MIS 5e benthic δ18O plateau, and the major glacial inception. SSTs south of Greenland followed a two-step cooling during the glacial inception similar to the pattern observed across much of the North Atlantic and Europe. Benthic δ18O increases in parallel, suggesting that this two-step cooling is linked to a two-phased intensification of Northern Hemisphere glaciation.