Séminaire du Lhyges le vendredi 19 mai à 11h.
Intervenant : Daniel Emilio Martinez, Principal Researcher of the National Council of Scientific and Technical Research (CONICET), Professor of the National University of Mar del Plata, Argentina.
Titre : "Geochemical and isotopic views on the regional Quaternary aquifer in the Pampeana Plain, Argentina".
Résumé :
The geographical region known as Pampeana Plain in Argentina corresponds approximately to a large structural basin occupying the central sector of the country, with a total area over 1,500,000 km2. During the Pleistocene a large and continuous sedimentation of wind carried particles, mainly coming from the Andean volcanoes, take place. These deposits form an important aquifer which supports around 60% of the national GDP. Despite the advantages of the widespread accessibility of groundwater, the heterogeneity of the sedimentary sequences makes necessary the application of geochemical and isotopic tools in order to improve the understanding of the system.
A general description of the basin origin and the main geochemical processes determining the groundwater composition is presented. Special consideration is done on specific troubles like marine intrusion, the upward flow of saline waters and arsenic and fluoride contamination. The contribution of water isotopes and noble gasses to the interpretation of the flow conditions is shown in some very well studied points.