Impact of rock weathering on the chemical composition of groundwater determined by inverse modeling in large sedimentary basins

Philippe Négrel (1) , Romain Millot (1) , Emmanuelle Petelet-Giraud (1) , Eline Malcuit (1) , Agnès Brenot (1)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

This study focuses on the geochemistry of groundwater in large Eocene aquifers sedimentary system with the main goals of investigating the influence of rock weathering and quantifying the inputs from each of several end-members (i.e silicate, carbonate, evaporite) by using an inverse method approach of budget equations. We report here the results obtained on 42 groundwater samples collected in a large aquifer (The) in the Adour-Garonne district (SW France). Mass budget equations solved using an inverse method allowed to estimate the contribution of the different sources among which, carbonate inputs dominate, evaporites often plays the second role, and silicate inputs may be important.

Domaines: Géochimie; Milieux et Changements globaux

Philippe Négrel, Romain Millot, Emmanuelle Petelet-Giraud, Eline Malcuit, Agnès Brenot. Impact of rock weathering on the chemical composition of groundwater determined by inverse modeling in large sedimentary basins. 14th International Symposium on Water-Rock Interaction, WRI 14, Jun 2013, Avignon, France. pp.615-619, ⟨10.1016/j.proeps.2013.03.135⟩. ⟨hal-00798218⟩