The transfer and storage of chemical elements in particulate matter are controlled by physical, chemical and biological processes. Their dynamics are well understood, especially in environments that show strong tectonic and/or geomorphic pressures, and are frequently reconstructed over centuries or decades to evaluate climate change effects for example. However, observations carried out at high spatial and temporal resolutions are less common, particularly in lowland areas. The present study aimed to better understand the links between earth surface processes, such as soil weathering and erosion, by combining pedology, geochemistry and hydrology at a small catchment scale. It focuses on the transfer of selected chemical elements (Ca, K, Ti, Fe, Mn, Rb and Sr) associated with particulate erosion and transport. The first (topsoil) and last (subsoil) soil horizons from different soil profiles and stream bed-load sediments of the Egoutier catchment (8 km2, Loiret, France) were studied. The objective was to investigate the relationship between the weathering and erosion processes. The soils are developed on ancient alluvium as evidenced by their physical and chemical properties, which clearly displayed a weathering profile from bedrock to topsoil layers. Ca, Fe and Rb showed migration dynamics from the topsoils to the subsoils, whereas Mn appeared immobilized within topsoils. Enrichments of all investigated elements increased in bed-load sediments. Topsoil erosion is the main source of sediment. However, Fe and Rb enrichments also highlight the remobilization of subsoils during periods of enhanced precipitation. Furthermore, Fe and Rb enrichments show a selective erosion of clay minerals. K and Sr contents evidence mineral break-up processes favoring mechanical erosion of all mineral phases. Moreover, their enrichments can be interpreted as the result of higher erosion rates and deposition during high rainfall events. The same conclusion can be drawn for Mn and Ca although their spatial variabilities depend on contributions from runoff in urban areas, as rainwaters from anthropized areas supply Ca mineral phases and diluted Mn depleted bearing phases from topsoil layers.

中文翻译：

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流域尺度下沉积物空间和时间演化的地球化学见解（法国埃古捷流）

颗粒物中化学元素的转移和储存受到物理、化学和生物过程的控制。它们的动态是众所周知的，特别是在显示出强烈构造和/或地貌压力的环境中，并且经常在几个世纪或几十年内重建以评估气候变化影响。然而，以高空间和时间分辨率进行的观测并不常见，尤其是在低地地区。本研究旨在通过在小流域范围内结合土壤学、地球化学和水文学，更好地了解地球表面过程之间的联系，例如土壤风化和侵蚀。它侧重于与颗粒侵蚀和传输相关的选定化学元素（Ca、K、Ti、Fe、Mn、Rb 和 Sr）的转移。研究了来自不同土壤剖面的第一个（表土）和最后一个（底土）土壤层以及 Egoutier 流域（8 平方公里，法国卢瓦雷特）的河流床载沉积物。目的是调查风化和侵蚀过程之间的关系。土壤是在古老的冲积层上发育的，其物理和化学特性证明了这一点，它们清楚地显示了从基岩到表土层的风化剖面。Ca、Fe 和 Rb 显示出从表土到底土的迁移动态，而 Mn 似乎固定在表土中。床载沉积物中所有研究元素的富集增加。表层土壤侵蚀是沉积物的主要来源。然而，Fe 和 Rb 的富集也突出了降水增强期间底土的再活化。此外，Fe 和 Rb 富集显示出粘土矿物的选择性侵蚀。K 和 Sr 含量证明矿物分解过程有利于所有矿物相的机械侵蚀。此外，它们的富集可以解释为高降雨事件期间较高的侵蚀率和沉积的结果。对于 Mn 和 Ca 可以得出相同的结论，尽管它们的空间变异性取决于城市地区径流的贡献，因为来自人类化地区的雨水提供了 Ca 矿物相和来自表土层的稀释的 Mn 耗尽轴承相。