Description du sujet de thèse

Plio-Quaternary paleogeographic evolution of the western Alpine piedmont (France) by multi-method analysis and dating of morpho-sedimentary archives

Contexte de travail

The Earth's surface dynamics is the result of complex interactions between internal (tectonic) and external (climate) forcing factors. Alluvial terrace sequences, i.e. former river floodplains that have undergone subsequent tectonic deformation and climate-related transformations (e.g. pedogenesis), provide particularly rich records of landscape evolution. Since the Alpine foreland basins accumulate sediments generated by (glacio-)fluvial erosion and transport occurring in the adjacent mountain range, knowledge of the chronostratigraphic record of key areas such as the Bas-Dauphiné and the Dombes (western Alpine foreland) can help to reconstruct and quantify long-term landscape evolution, paleogeographic changes (structuring of the Rhône and Isère watersheds upstream) and sediment budgets in the past.
Studying those sedimentary archives also offers key opportunities to (1) better understand the clastic sedimentary dynamics and deposition patterns during past global climate changes, (2) question the temporal evolution of ecosystems over recent geological past, and (3) characterize the landscapes and environments that were exploited by early human societies. These research outcomes can then serve as training sets for generating future landscape evolution scenarios. Finally, Plio-quaternary alluvial sequences deposited in the alpine foreland basins often host groundwater resources (aquifers) of major importance to societies. Providing new constraints on the 3D architecture of these aquifers at the scale of the western Alpine piedmont thus participates in the evaluation of future opportunities and challenges of their management.
Within the framework of an interdisciplinary scientific project based at the “Environnement Ville Société” (EVS Lyon) laboratory, the PhD student will lead a research work co-financed by the “Référentiel Géologique de la France” program (RGF, BRGM) and the H2O'Lyon Graduate School.