PhD project in co-tutorship at U. Avignon/UQAM: Modeling of processes leading to isotopic record of behavior of continental hydrosystems by limestone concretions.
This thesis aims to establish the control factors and mechanisms at the origin of the recording of isotopic signatures during the precipitation of calcareous concretions at the level of the sources. From targeted laboratory experiments, a numerical modeling of the coupled behavior of the chemistry of major elements (Ca, Mg) and isotopologues (13C-12C, 18O-16O) will be proposed (a modeling of the behavior of trace elements (Sr, Ba, Ra) and stable isotopes of strontium may also be considered if the opportunity arises). It aims to transcribe the variations of chemical and isotopic compositions of calcareous concretions into variations of hydrological factors (flow of sources and recharge rate). This modeling approach will be extended to data from travertine deposits (Turkey, Spain, France, Poland) to reconstruct the response of sources to recent climate changes and groundwater abstraction.
(13C-12C, 18O-16O) sera proposée (une modélisation du comportement des éléments traces (Sr, Ba, Ra) et des isotopes stables du strontium pourra également être envisagée si l’opportunité se présente). Elle vise à transcrire les variations de compositions chimiques et isotopiques des concrétions calcaires en des variations de facteurs hydrologiques (débit des sources et taux de recharge). Cette approche de modélisation sera étendue à des données issues de dépôts de travertins (Turquie, Espagne, France, Pologne) pour reconstituer la réponse des sources aux changements récents du climat et aux prélèvements d’eau souterraine.