Deepwater evolution in the inner Labrador Sea over the last 30 ka BP (DEEPTELLs)

拉布拉多海水（LSW）的形成是通过拉布拉多海的深水对流，被认为是稳定了大约7 kaBP以来的现代海洋环流。尽管其在现代海洋环流的重要性，有人认为，在拉布拉多海的深水形成是一个独特的功能，在全新世，并没有发生在最后一个冰期。相反，从拉布拉多海深水流出通道中哈特拉斯角外沉积物岩心中的底栖有孔虫重建的低冰川三角洲13 C特征被解释为到达高北方纬度的南方来源深水。这种简化的概念最近受到质疑，因为需要考虑源自北大西洋地区的冰川深水端元组成的变化，甚至拉布拉多海的深水地层。以前对拉布拉多海的研究是基于沉积学和地表水重建，因此对拉布拉多海的冰川和冰消期深水组成和结构知之甚少。在拟议的研究中，我们的目标是重建在拉布拉多海的水团结构和组成在末次冰期和冰消期，以测试是否LSW形成活跃在末次冰期和它的重要性，为冰川状态的大西洋翻转环流（AMOC）。重建工作将在拉布拉多内海水深1200至3300米处采集的四个沉积岩芯上进行，覆盖了填充拉布拉多海的不同深水物质。为了确定潜在的端元组成变化，将使用底栖有孔虫的δ 13 C和δ 18 O分析以及底栖有孔虫和介形类的Mg/Ca温度重建。研究结果有助于更好地了解拉布拉多海对全球冰消期AMOC变化和更稳定的AMOC模态的重要性。这对于评估拉布拉多海在人为强迫气候变暖下的重要性也至关重要，并应有助于进一步测试和改进用于预测未来气候变化的气候模型。

The formation of Labrador Sea Water (LSW) through deepwater convection in the Labrador Sea is supposed to stabilize the modern ocean circulation since about 7 ka BP. Despite its importance in the modern ocean circulation, it is suggested that deepwater formation in the Labrador Sea is a unique feature in the Holocene and did not occur during the last Glacial period. Instead, low glacial delta13C signatures reconstructed from benthic foraminifera in sediment cores off Cape Hatteras in the outflow pathway of deepwater from the Labrador Sea are interpreted as southern sourced deepwater that reached up to high northern latitudes. This simplified concept is recently questioned, as changes in the end member composition of the glacial deepwater originating from the North Atlantic region and even deepwater formation in the Labrador Sea need to be considered. Previous studies from the Labrador Sea are based on sedimentological and surface water reconstruction, thus little is known about the glacial and deglacial deepwater composition and -structure in the Labrador Sea. In the proposed study we aim to reconstruct the water mass structure and composition in the Labrador Sea during the last Glacial and the Deglaciation in order to test whether LSW formation was active during the last Glacial and which importance it had for the glacial state of the Atlantic Overturning Circulation (AMOC). The reconstructions will be conducted on four sediment cores taken in the Inner Labrador Sea at water depth between 1200 and 3300 m, covering the different deepwater masses that are filling the Labrador Sea. To identify potential end member composition changes, delta13C and delta18O analyses on benthic foraminifera and Mg/Ca temperature reconstruction from benthic foraminifera and ostracods will be used. The results of the study can help to gain a better understanding of the importance of the Labrador Sea for the Glacial and Deglacial global AMOC changes and for more stable AMOC modes. This will be also pivotal to assess the importance of the Labrador Sea under anthropogenic forced climate warming and should help to further test and improve climate models used to predict future climate change.