Age determinaton and age model of sediments from the Bay of Biscay@en

Continuous high-resolution mass accumulation rates (MAR) and X-ray fluorescence (XRF) measurements from marine sediment records in the Bay of Biscay (NE Atlantic) have allowed the determination of the timing and the amplitude of the 'Fleuve Manche' (Channel River) discharges during glacial stages MIS 10, MIS 8, MIS 6 and MIS 4-2. These results have yielded detailed insight into the Middle and Late Pleistocene glaciations in Europe and the drainage network of the western and central European rivers over the last 350 kyr. This study provides clear evidence that the 'Fleuve Manche' connected the southern North Sea basin with the Bay of Biscay during each glacial period and reveals that 'Fleuve Manche' activity during the glaciations MIS 10 and MIS 8 was significantly less than during MIS 6 and MIS 2. We correlate the significant 'Fleuve Manche' activity, detected during MIS 6 and MIS 2, with the extensive Saalian (Drenthe Substage) and the Weichselian glaciations, respectively, confirming that the major Elsterian glaciation precedes the glacial MIS 10. In detail, massive 'Fleuve Manche' discharges occurred at ca 155 ka (mid-MIS 6) and during Termination I, while no significant discharges are found during Termination II. It is assumed that a substantial retreat of the European ice sheet at ca 155 kyr, followed by the formation of ice-free conditions between the British Isles and Scandinavia until Termination II, allowed meltwater to flow northwards through the North Sea basin during the second part of the MIS 6. We assume that this glacial pattern corresponds to the Warthe Substage glacial maximum, therefore indicating that the data presented here equates to the Drenthe and the Warthe glacial advances at ca 175-160 ka and ca 150-140 ka, respectively. Finally, the correlation of our records with ODP site 980 reveals that massive 'Fleuve Manche' discharges, related to partial or complete melting of the European ice masses, were synchronous with strong decreases in both the rate of deep-water formation and the strength of the Atlantic thermohaline circulation. 'Fleuve Manche' discharges over the last 350 kyr probably participated, with other meltwater sources, in the collapse of the thermohaline circulation by freshening the northern Atlantic surface water.

来自东北大西洋比斯开湾海洋沉积物记录的连续高分辨率质量堆积速率（MAR）与X射线荧光光谱（XRF）测量数据，使得研究人员得以确定MIS 10（海洋同位素阶段10）、MIS 8、MIS 6以及MIS 4-2冰期阶段内，曼恩河（Fleuve Manche，英吉利河）的入海径流时间与规模。上述研究结果为欧洲中更新世晚期至晚更新世冰期演化，以及过去35万年以来西欧与中欧河流的流域网络格局，提供了详尽的认知视角。本研究提供了明确证据，证明每一个冰期阶段内曼恩河均连通了北海南部盆地与比斯开湾；同时揭示出MIS 10与MIS 8冰期内的曼恩河径流活动规模显著低于MIS 6与MIS 2冰期。研究团队将MIS 6与MIS 2冰期内观测到的显著曼恩河径流活动，分别对应大规模萨利安冰期（德伦特亚阶）与威斯康星冰期，由此证实主要的埃尔斯特冰期早于MIS 10冰期。具体而言，大规模曼恩河径流事件发生于约15.5万年前（MIS 6中期）以及冰期终止期I期间，而冰期终止期II期间未观测到显著径流活动。研究推测，约15.5万年前欧洲冰盖发生大规模退缩，随后不列颠群岛与斯堪的纳维亚半岛之间形成无冰区域，直至冰期终止期II，这使得融水在MIS 6的后半段得以沿北海南部盆地向北流动。我们认为该冰期模式对应瓦尔泰亚阶冰期鼎盛期，由此表明本次发布的数据分别对应约17.5万-16万年前的德伦特冰进与约15万-14万年前的瓦尔泰冰进。最后，将本研究记录与大洋钻探计划（ODP）980站位数据进行对比后发现，与欧洲冰体部分或完全消融相关的大规模曼恩河径流事件，与深水形成速率以及大西洋热盐环流强度的显著减弱同步发生。过去35万年来的曼恩河径流或许与其他融水水源一道，通过淡化北大西洋表层海水，参与了热盐环流的崩溃过程。