Mediterranean Outflow Water (MOW) adds salt and density to open ocean intermediate waters and is therefore an important motor of Atlantic meridional overturning circulation (AMOC) and climate variability. However, the variability in strength and depth of MOW on geological timescales is poorly documented. Here we present new detailed records, with excellent age control, of MOW variability from 416 ka to present from rapidly accumulated marine sediments recovered from the West Iberian Margin during Integrated Ocean Drilling Program (IODP) Expedition 339. Our records of X‐ray fluorescence (XRF), physical grain size, and paleocurrent information from the anisotropy of magnetic susceptibility (AMS) indicate (i) a close relationship between the orientation of principle AMS axes and glacial‐interglacial cycles and (ii) two distinct regimes of MOW behavior over the last ~416 kyr in grain‐size and AMS variability at orbital (mainly precessional) and suborbital timescales. Between marine isotope stage (MIS) 10 and MIS 4, MOW was focused at a generally shallow depth on the West Iberian Margin, and changes in MOW strength were strongly paced by precession. A transition interval occurred during MISs 5 and 4, when MOW deepened and millennial‐scale variability in flow strength was superimposed on orbitally paced change. During MIS 11 and from MIS 3 to present, MOW was deeply focused and millennial‐scale variability dominated. We infer that late Pleistocene variability in MOW strength and depth were strongly climate influenced and that changes in circum‐Mediterranean rainfall climate were likely a primary control.

中文翻译：

---

更新世晚期地中海向北大西洋的地中海流出的气候变化

地中海外流水（MOW）为开阔的海洋中间水域增加了盐分和密度，因此是大西洋经向翻转循环（AMOC）和气候多变性的重要动力。然而，在地质时间尺度上，MOW的强度和深度的变化性文献很少。在这里，我们提供了新的详细记录，其精确的年龄控制是从416 ka到MOB可变性的最新记录，这些记录是在综合海洋钻探计划（IODP）远征339期间从西伊比利亚边缘采集的快速累积的海洋沉积物中得到的。我们的X射线荧光记录XRF），物理粒度，来自磁化率各向异性（AMS）的古电流信息表明（i）AMS原理轴的方向与冰川-冰晶间的循环之间存在密切的关系，并且（ii）晶粒在最后一个〜416历程中MOW行为的两个不同状态轨道（主要是进动）和亚轨道时标的大小和AMS变异性。在海洋同位素阶段10（MIS）和MIS 4之间，MOW集中在西伊比利亚边界的一个较浅的深度上，MOW强度的变化受到岁差的强烈影响。在MIS 5和MIS 4中发生过渡间隔，这是因为MOW加深了，流动强度的千禧年尺度变化叠加在了轨道上的变化上。在MIS 11以及从MIS 3到现在的过程中，MOW着重关注，并且千禧年规模的可变性占主导地位。