Petersen J.O., Deschamps Pierre, Hamelin Bruno, Goncalves J., Michelot J.L., Zouari K. (2013). Water-rock interaction and residence time of groundwater inferred by U-234/U-238 disequilibria in the Tunisian Continental Intercalaire aquifer system. In :
Hellmann R. (ed.), Pitsch H. (ed.). Proceedings of the fourteenth international symposium on water-rock interaction (WRI 14). Procedia Earth and Plantetary Science, 7, p. 685-688. International Symposium on Water-Rock Interaction, 14., Avignon (FRA), 2013/06/09-14. ISSN 1878-5220.
Titre du document
Water-rock interaction and residence time of groundwater inferred by U-234/U-238 disequilibria in the Tunisian Continental Intercalaire aquifer system
Année de publication
2013
Auteurs
Petersen J.O., Deschamps Pierre, Hamelin Bruno, Goncalves J., Michelot J.L., Zouari K.
In
Hellmann R. (ed.), Pitsch H. (ed.), Proceedings of the fourteenth international symposium on water-rock interaction (WRI 14)
Source
Procedia Earth and Plantetary Science, 2013,
7, p. 685-688 ISSN 1878-5220
Colloque
International Symposium on Water-Rock Interaction, 14., Avignon (FRA), 2013/06/09-14
The uranium content and 234U/238U ratios have been measured in more than thirty groundwater samples over the Tunisian part of the Continental Intercalaire (CI) aquifer. In this large artesian aquifer, uranium behavior is mainly controlled by redox front systems. The uranium concentrations vary by 5 orders of magnitude from 10-4 to 20 ppb and the (234U/238U) activity ratio from 1 to 10. Close to CI outcrops in the Dahar Mountains, the stepwise decrease in U concentrations combined with a significant increase of the (234U/238U) ratio up to 10 ("augmenting regime") is followed, downflow by a (234U/238U) decrease up to 3 ("decaying regime"), clearly indicating the occurrence of a redox front. We will discuss the significance of 234U-238U disequilibria in terms of water residence times and its potential to trace water-rock interaction mechanisms.
Plan de classement
Transports solides et qualité physico-chimique des eaux [062MECEAU04]
;
Géochimie [064GEOCHI]
Descripteurs
EAU SOUTERRAINE ; AQUIFERE ; HYDROGEOLOGIE ; QUALITE DE L'EAU ; URANIUM ; ECHANTILLONNAGE ; ANALYSE CHIMIQUE ; METHODOLOGIE ; MASSIF ; INTERACTION ROCHE EAU
Description Géographique
TUNISIE
Localisation
Fonds IRD [F B010065837]
Identifiant IRD
fdi:010065837
