Variability of the Mediterranean Outflow on glacial-interglacial and millennial time scales

地中海外流水（MOW）通过对大西洋中层盐度收支的贡献，对北大西洋晚更新世古海洋学和气候演变产生了重要影响。由于直布罗陀的底床深度较浅（286米），海平面的变化以及地中海和热带大西洋环流的水文变化对MOW产生了很大影响。在这项研究中，我们建议重建详细的流动路径，流动强度和过去的混合MOW与其他东北大西洋水体通过放射性同位素分析钕（Nd）和铅（Pb），这有可能解开MOW的演变在前所未有的细节和精度。我们将从大量沉积物的自生铁锰涂层中提取底部沃茨的溶解放射性同位素特征。粘土部分的同位素组成将提供独立的限制过去的水流路径的水团。这项研究将进行一套从葡萄牙的边缘，加迪斯湾，并从阿尔沃兰海在西地中海，这将使重建MOW动力学在大西洋东部约30万年的半远洋沉积物的井芯。最近的许多证据表明，MOW在最后一次重大气候转变（终止1）期间对海洋学变化起着关键作用，这就是为什么特别强调在这段时间内MOW变化的高分辨率记录。

Mediterranean Outflow Water (MOW) has exerted significant influence on the Late Pleistocene paleoceanography and climate evolution in the North Atlantic region through its contribution to the mid-depth Atlantic salinity budget. The MOW has been strongly influenced by changes in sea level due to the shallow (286 m) sill depth of the Strait of Gibraltar but also by changes in the hydrology of the Mediterranean Sea and the tropical Atlantic gyre. In this study we propose to reconstruct in detail the flow path, flow strength and past mixing of MOW with other eastern North Atlantic water masses through radiogenic isotope analyses of neodymium (Nd) and lead (Pb), which have the potential to unravel the evolution of MOW at unprecedented detail and precision. We will extract the dissolved radiogenic isotope signatures of bottom waters from authigenic ferromanganese coatings of bulk sediments. The isotope composition of the clay fraction will provide independent constraints on the past flow paths of the water masses. The study will be carried out on a suite of well-dated cores of hemipelagic sediments from the Portuguese margin, the Gulf of Cadiz, and from the Alboran Sea in the Western Mediterranean, which will allow the reconstruction of MOW dynamics in the eastern Atlantic Ocean back to approximately 30 ka. A lot of recent evidence points to a critical role of MOW for oceanographic changes during the last major climatic transition (Termination 1), which is why particular emphasis will be on a high resolution record of MOW variability during this period of time.