Géosciences de surface (Hydrologie-Hydrogéologie) Eaux fortement minéralisées et circulations profondes dans le socle. Exemple des Alpes franco-italiennes

Highly mineralised waters and deep groundwater circulation in crystalline basement. Example in the French–Italian Alps. The presence in the French–Italian Alps of several springs characterized by a high sodium–chloride content, depleted in oxygen-18, tritium free and with low carbon-14 activity, is well known. The geological, hydrological, and geochemical studies in progress for the new high-speed railway tunnel crossing the French–Italian Alps, show, in the drilled boreholes at a mean elevation of 700 masl, the presence of brines. Brines appear to be the basis of the geological, structural, and hydrodynamic systems, and fill the largest faults and the main tectonic cont acts. The brines squeezed by tectonic activity, are mobilised at