Manière, Louis; Grosbois, Cécile; Dhivert, Elie; Mondamert, Leslie; Labanowski, Jérôme; Meybeck, Michel: Spatial and temporal variations of major and trace elements in sediments of the Loire River basin (France, 1850-2022) [dataset bundled publication]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.986591 (dataset in review)

This dataset contains geochemical analyses (major and trace elements) of 15 sediment cores, 17 river bank sediment profiles and 91 surface sediment samples collected in the Loire River basin. The sampling campaign began in 2009 with the first coring survey at the most downstream station of the Loire River and continued until 2022 throughout the whole basin except the estuary. The aim of this data collection was to characterize spatial and temporal trends of these elements over the recorded period in sediments (minimum the last 50 years) and trace element transfers along the sediment cascade of the Loire River and its main tributaries. Analyses focused on major and trace elements compositions (heavy metals and metalloids), all conducted using the same analytical procedures at the French National Centre for Scientific Research (CNRS) SARM-CRPG facilities (Nancy, France; https://sarm.cnrs.fr). In addition, total and organic carbon, grain-size and 137Cs measurements were carried out at the GéHCO research unit (University of Tours) and at the LSCSE research unit (CEA-CNRS-UNSQ) respectively. This large distribution of sediment chemical composition covers the main geological formations drained by the Loire River and its tributaries, including the upstream French Massif Central and the downstream Armorican Massif, characterized by crystalline and volcanic bedrock, as well as the sedimentary bedrock of the southern Paris Basin in the middle basin. A wide range of anthropogenic activities were also considered throughout the basin, from mining and associated ore-processing operations to urban and industrial activities. This dataset provides a spatial and temporal perspective on the evolution of numerous chemical elements at the Loire River basin scale. It can be used to compare the Loire sediment composition to other river basins, to assess the influence of anthropogenic sources on aquatic environments, and to define geochemical fingerprints of historical sources abandoned over several decades.