Delayed hydrological response to Greenland cooling at the onset of the Younger Dryas in western Europe
Delayed hydrological response to Greenland cooling at the onset of the Younger Dryas in western Europe
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DOI：
10.1038/ngeo2053
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发表时间：
2014-02
影响因子：
18.3
通讯作者：
O. Rach;A. Brauer;H. Wilkes;D. Sachse
中科院分区：
文献类型：
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作者：
O. Rach;A. Brauer;H. Wilkes;D. Sachse
最后一次冰消期的总体变暖趋势被新仙女木打断，这是一个突然变冷和广泛环境变化的时期，，。冰芯记录显示，格陵兰岛的突然冷却始于12,846年前，比西欧的重大环境和植被变化早了大约170年，这一变化被经典地定义为新仙女木。然而，这种时间上的差异福尔斯在年龄模型的不确定性范围内。在这里，我们使用的氢同位素组成的脂质生物标志物，从Meerfelder Maar湖的精确定年纹沉积物重建西欧的水文气候。我们观察到12，850年前水生和陆地脂质的氢同位素值下降，表明该地区的气候变冷与格陵兰岛的突然变冷同步。第二次下降发生在170年后，主要是在水生脂质的氢同位素记录，但在较小程度上在陆地脂质，我们归因于干旱化，以及水分来源和途径的变化。因此，我们确认，确实有一个冷却和大量的水文和环境变化之间的滞后在西欧。我们认为这种延迟与北大西洋海冰的扩张以及随后西风系统的南移有关。我们进一步认为，这些水文变化放大了西欧的环境变化在新仙女木的开始。
The general warming trend of the last deglaciation was interrupted by the Younger Dryas, a period of abrupt cooling and widespread environmental change,,,,,,,,,. Ice core records suggest the abrupt cooling began 12,846 years ago in Greenland, about 170 years before the significant environmental and vegetation change in western Europe classically defined as the Younger Dryas. However, this difference in timing falls within age model uncertainties. Here we use the hydrogen isotope composition of lipid biomarkers from precisely dated varved sediments from Lake Meerfelder Maar to reconstruct hydroclimate over western Europe. We observe a decrease in the hydrogen isotope values of both aquatic and terrestrial lipids 12,850 years ago, indicating cooling climate in this region synchronous with the abrupt cooling in Greenland. A second drop occurs 170 years later, mainly in the hydrogen isotope record of aquatic lipids but to a lesser extent in the terrestrial lipids, which we attribute to aridification, as well as a change in moisture source and pathway. We thus confirm that there was indeed a lag between cooling and substantial hydrologic and environmental change in western Europe. We suggest the delay is related to the expansion of sea ice in the North Atlantic Ocean and the subsequent southward migration of the westerly wind system. We further suggest that these hydrological changes amplified environmental change in western Europe at the onset of the Younger Dryas.