Abstract Lateglacial climatic oscillations exerted profound impacts on the Meuse fluvial system. In the Lower Meuse (southern Netherlands), geomorphological studies in the last decades mainly centred on Lateglacial vegetation evolution, channel pattern changes and river terrace formation. Little information has been reported about the paleohydrology and its relation with the regional climate conditions. This study investigates a sediment core that contains flood sediments deposited from the early Allerod up to the middle Holocene. We conducted grain size analysis, thermogravimetric analysis (organic matter and calcium carbonate content), pollen and macrofossil analysis, and determined the oxygen and carbon stable isotope ratios of biogenic carbonate (opercula of the freshwater gastropod Bithynia tentaculata). The chronology of the core is based on AMS 14C dating and pollen biostratigraphical correlation. The pollen and macrofossil studies reveal that the core site was a lake environment during the Allerod and Younger Dryas periods. The oxygen isotope record in conjunction with organic matter and carbonate content are believed to have captured the intra-Allerod Cold Period (IACP). The synchronous variation of oxygen and carbon isotopes with calcium carbonate content indicates a dominant evaporation effect on carbonate chemistry of the lake environments during the warm Allerod interstadial. End-member modelling decomposes the grain-size distributions into two sandy end members (bed load) and two silty-clayey end members (suspended load). In order to highlight the flood signal, we constructed two flood energy indexes (FEI-1 and FEI-2) that reflect the coarseness of the suspended load and bed load, respectively. Both indexes show a relatively high flood condition during the IACP, followed by a low flood phase in the Late Allerod and quickly intensified flood conditions at the onset of the Younger Dryas. In the second phase of the Younger Dryas, deposition of sandy aeolian sediments to the core site complicates the paleoflood identification using FEI-2 (bed load). This study shows a high sensitivity of the hydrological process and sedimentary environment at the Lower Meuse to the regional climate system.

中文翻译：

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Allerød-Younger Dryas 气候转变期间默兹河下游的快速洪水加剧和环境响应

摘要 晚冰期气候振荡对默兹河流系统产生了深远的影响。在下默兹（荷兰南部），过去几十年的地貌研究主要集中在晚冰期植被演化、河道格局变化和河流阶地形成。关于古水文及其与区域气候条件关系的报道很少。这项研究调查了一个沉积物核心，其中包含从早期 Allerod 沉积到全新世中期的洪水沉积物。我们进行了粒度分析、热重分析（有机质和碳酸钙含量）、花粉和大型化石分析，并确定了生物碳酸盐（淡水腹足动物 Bithynia tentaculata 的鳃盖）的氧和碳稳定同位素比率。核心的年表基于 AMS 14C 年代测定和花粉生物地层相关性。花粉和大型化石研究表明，核心地点是 Allerod 和 Younger Dryas 时期的湖泊环境。氧同位素记录连同有机物和碳酸盐含量被认为记录了阿勒罗德内部冷期 (IACP)。氧和碳同位素与碳酸钙含量的同步变化表明，在温暖的 Allerod 间质期间，蒸发对湖泊环境的碳酸盐化学具有主导作用。端部建模将粒度分布分解为两个砂质端部（床荷载）和两个粉质粘土端部（悬浮荷载）。为了突出洪水信号，我们构建了两个洪水能量指数（FEI-1 和 FEI-2），分别反映了悬浮荷载和床荷载的粗度。两个指数都显示了 IACP 期间相对较高的洪水状况，随后是晚 Allerod 的低洪水阶段，并在 Younger Dryas 开始时迅速加剧了洪水状况。在 Younger Dryas 的第二阶段，沙质风成沉积物沉积到核心位置使使用 FEI-2（床负荷）的古洪水识别变得复杂。这项研究表明，默兹河下游的水文过程和沉积环境对区域气候系统具有高度敏感性。随后是晚阿勒罗德的低洪水阶段，并在新仙女木开始时迅速加剧了洪水状况。在 Younger Dryas 的第二阶段，沙质风成沉积物沉积到核心位置使使用 FEI-2（床负荷）的古洪水识别变得复杂。这项研究表明，默兹河下游的水文过程和沉积环境对区域气候系统具有高度敏感性。随后是晚阿勒罗德的低洪水阶段，并在新仙女木开始时迅速加剧了洪水状况。在 Younger Dryas 的第二阶段，沙质风成沉积物沉积到核心位置使使用 FEI-2（床负荷）的古洪水识别变得复杂。这项研究表明，默兹河下游的水文过程和沉积环境对区域气候系统具有高度敏感性。