North Atlantic marine radiocarbon reservoir ages through Heinrich event H4: a new method for marine age model construction
North Atlantic marine radiocarbon reservoir ages through Heinrich event H4: a new method for marine age model construction
复制标题
通过 Heinrich 事件 H4 北大西洋海洋放射性碳储层年龄：海洋年龄模型构建的新方法
DOI：
--
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
P. Reimer
中科院分区：
文献类型：
--
作者：
J. Olsen;T. L. Rasmussen;P. Reimer
挪威-格陵兰海致密盐水的冷却和下沉对北大西洋深水的形成至关重要。挪威-格陵兰海的对流使得温暖的地表水向北流动，冷盐水向南输送。这种循环系统对气候变化高度敏感，并以不同的模式运行。末次冰期以暖间冰期和冷间冰期的千年尺度Dansgaard-Oeschger （D-O）事件为特征。类似的千年尺度变化（与D-O事件有关）在海洋核中也很明显，这表明大气和海洋环流系统存在很强的耦合。特别持久的寒冷气候与北大西洋海因里希事件有关，在海因里希事件中，从大陆上释放出来的冰山导致融水在北大西洋北部和北欧海域扩散。据信，融水层导致了深层对流的停止或接近停止，从而导致了寒冷的气候。融水的扩散和海洋环流的变化对大气与深海之间的碳交换有较大的影响，导致表层海洋14C活动的深刻变化。这里我们展示了海因里希事件H4的海相14C储层年龄(R)高达约2000年。我们的R估计是基于一种新的年龄模型构建方法，该方法使用基于间期突变变暖的已识别的温度层和结合点。
Abstract Cooling and sinking of dense saline water in the Norwegian–Greenland Sea is essential for the formation of North Atlantic Deep Water. The convection in the Norwegian–Greenland Sea allows for a northward flow of warm surface water and southward transport of cold saline water. This circulation system is highly sensitive to climate change and has been shown to operate in different modes. In ice cores the last glacial period is characterized by millennial-scale Dansgaard–Oeschger (D–O) events of warm interstadials and cold stadials. Similar millennial-scale variability (linked to D–O events) is evident from oceanic cores, suggesting a strong coupling of the atmospheric and oceanic circulations system. Particularly long-lasting cold stadials correlate with North Atlantic Heinrich events, where icebergs released from the continents caused a spread of meltwater over the northern North Atlantic and Nordic seas. The meltwater layer is believed to have caused a stop or near-stop in the deep convection, leading to cold climate. The spreading of meltwater and changes in oceanic circulation have a large influence on the carbon exchange between atmosphere and the deep ocean and lead to profound changes in the 14C activity of the surface ocean. Here we demonstrate marine 14C reservoir ages (R) of up to c. 2000 years for Heinrich event H4. Our R estimates are based on a new method for age model construction using identified tephra layers and tie-points based on abrupt interstadial warmings.