Tracing Sediment Sources Using Strontium Isotopes in a Pond Draining an Agricultural Catchment (Loire River Basin, France)

Marion Le Gall (1, 2) , O. Evrard (1, 2) , François Thil (1, 3) , Anthony Foucher (4) , Sébastien Salvador-Blanes (4) , Olivier Cerdan (5) , Sophie Ayrault (1, 2)

1 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
2 GEDI - Géochimie Des Impacts
3 GEOTRAC - Géochrononologie Traceurs Archéométrie
4 GéHCO EA6293 - GéoHydrosystèmes COntinentaux
5 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

Soil erosion in agricultural catchments leads to the accelerate supply of sediment to rivers. Here, we determine the sources contributing to the siltation of a pond in the Louroux catchment (24 km², French Loire River basin), representative of lowland agricultural environments of Northwestern Europe. Strontium isotopic ratios were determined in potential sources and sediment core samples collected in the Louroux pond, at the outlet of the catchment. These ratios were shown to provide good discrimination between different sediment sources (soil, suspended particulate matter, calcareous rock samples), and their respective contributions were calculated using mass balance equations. These results should be used to guide the implementation of soil conservation measures to limit sediment supply to the Louroux River.

Mots clés: end-member; Panoply; mass balance equation; core sediment; 87 Sr/ 86 Sr isotopic ratio; soil erosion

Domaines: Interfaces continentales, environnement; Science des sols; Hydrologie; Géochimie; Géomorphologie

Marion Le Gall, O. Evrard, François Thil, Anthony Foucher, Sébastien Salvador-Blanes, et al.. Tracing Sediment Sources Using Strontium Isotopes in a Pond Draining an Agricultural Catchment (Loire River Basin, France). Procedia Earth and Planetary Science, 2015, 13, pp.30 - 34. ⟨10.1016/j.proeps.2015.07.007⟩. ⟨hal-01806108⟩