Variability of (sub)surface water masses at the Iberian Margin during the mid-Pleistocene

在中更新世（0.7 - 1.2 Ma），冰川旋回从41 kyrs转移到100 kyrs。这一时期，“中更新世革命”（MPR），伴随着气候系统的根本变化，记录冰川冰量的快速增长，北大西洋的冷却和季风强度的增强。大气环流的伴随变化应该影响到风驱动的海洋表面环流，如北大西洋副热带环流。作为一个重要的热盐库，后者构成了大西洋温盐环流的一个关键部分。更好地了解其相对于MPR的长期演变是重要的，但到目前为止还没有很好地受到数据的约束。为了填补这一空白，拟议项目的目的是重建中更新世海面和温跃层温度和盐度在伊比利亚边缘（地点U1385，IODP Exp。339）。这将通过结合δ 18 O和Mg/Ca分析浅和深居浮游有孔虫来完成，分辨率约为0.5至1 kyr。伊比利亚边缘南部是进行拟议的古海洋学研究的理想地点，因为该地点的表层沃茨受到高纬度气候过程的影响，但也受到亚热带环流沃茨的影响。另一方面，底栖记录可以与反映冰量变化的南极气候波动联系起来。这种特殊的情况下，可以确定跨半球的相位关系的海洋-大气系统具有很大的地层信心。生成的数据将记录边界条件的变化，特别是冰量的变化如何影响亚热带环流沃茨的空间延伸和特征。

During the mid-Pleistocene (0.7 – 1.2 Ma), glacial cyclicity shifted from 41 kyrs to 100 kyrs. This period, the “Mid-Pleistocene Revolution” (MPR), was accompanied by a fundamental change of the climate system, documented by rapid growth of glacial ice volume, cooling in the North Atlantic and enhanced monsoonal strength. Concomitant shifts in atmospheric circulation should have affected the wind-driven oceanic surface circulation such as the North Atlantic subtropical gyre. As an important heat and salt reservoir, the latter con-stitutes a pivotal part of the Atlantic thermohaline circulation. A better understanding of its long-term evolution with respect to the MPR is important but not well-constrained by data so far. To fill this gap, the pro-posed project aims on the reconstruction of mid-Pleistocene sea-surface and thermocline temperatures and salinities at the Iberian Margin (Site U1385, IODP Exp. 339). This will be done by combined δ18O and Mg/Ca analyses on shallow and deep dwelling planktonic foraminifera in ~0.5 to 1 kyr resolution. The southern Iberian Margin is ideally suited for the proposed paleoceanographic study since surface waters at this location are influenced by high-latitude climate processes but are also affected by subtropical gyre waters. Benthic records, on the other hand, can be linked to Antarctic climate fluctuations reflecting changes in ice volume. This particular situation allows the determination of inter-hemispheric phase relations within the ocean-atmospheric system with great stratigraphic confidence. The generated data will document how changed boundary conditions, in particular ice volume, influenced the spatial extension and characteristics of subtropical gyre waters.