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首页> 外文期刊>Estuarine Coastal and Shelf Science >Seasonal variations in the characteristics of superficial sediments in a macrotidal estuary (the Seine inlet, France)
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Seasonal variations in the characteristics of superficial sediments in a macrotidal estuary (the Seine inlet, France)

机译：巨潮河口（法国塞纳河入海口）表层沉积物特征的季节性变化

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摘要

Seasonal variations in the sedimentary regime in the mouth of the Seine river, a macrotidal estuary, are described for a 3-year period. The aim of this study is to characterize and to understand the main governing mechanisms, using data from more than a thousand of superficial sediment grab samples or box cores gathered throughout the study period. Analyses of lithofacies and rheo-logical properties were carried out. The distribution of sediments is governed by seasonal meteorological variations. The surface covered by mud reaches a maximum (40% of the total mouth area) during winter. After the winter, the soft mud deposits are progressively redistributed throughout the whole estuary area and onto the shelf. During the lowest freshwater flow at the end of summer, the fine-grained sediments cover less than 20% of the river mouth area. These seasonal variations mainly depend on the river discharge intensity, but are also linked to wave activity. In the study area, the amount of fine-grained deposits after high river flow periods depends on (1) volume of mud erodable within the estuary, (2) the duration of the flood tidal influx, and (3) the duration preceding the particular annual high river flow. During the last decades, filling of the estuary upstream from Honfleur has led to a downstream shift of the fine-grained sediment deposition area; following this, the present-day mud deposition area is in the open part of the estuary, in the subtidal shallow area. Subsequently, fresh mud deposits undergo intense hydrodynamical and meteorological effects, and are partly reworked by waves and tidal currents effects. In this study, it is shown that the behaviour of suspended matter and of superficial sediments is strongly influenced by short but intense events including high river flows and gales.
机译：塞纳河河口（一个大潮河口）的沉积状态随季节变化为期三年。这项研究的目的是使用整个研究期间收集的上千个表面沉积物抓取样品或箱芯的数据来表征和理解主要的治理机制。进行岩相和流变学特性分析。沉积物的分布受季节性气象变化的影响。冬季，被泥覆盖的表面最大（占口部总面积的40％）。冬季过后，软泥沉积物将逐渐在整个河口区域重新分布到架子上。在夏季末淡水流量最低的时候，细颗粒的沉积物覆盖不到河口面积的20％。这些季节变化主要取决于河流的排放强度，但也与波浪活动有关。在研究区域中，高流量时期后的细颗粒沉积物的数量取决于（1）河口内易蚀泥浆的体积，（2）潮汐潮涌的持续时间和（3）特定潮汐之前的持续时间每年高河流量。在过去的几十年中，翁弗勒尔上游的河口被填满，导致细颗粒沉积物沉积区域向下游移动。此后，目前的泥沙沉积区域位于河口的开放部分，即潮下浅水区。随后，新鲜的泥浆沉积物经历了强烈的水动力和气象作用，并由于波浪和潮流影响而部分地被重新加工。在这项研究中，研究表明，悬浮物和表层沉积物的行为受到短暂但强烈的事件的强烈影响，包括高流量的河流和大风。

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