• Researcher: Rocio Jaimes
• Host institution: Université de Genève
• Supervisor: Sébastien Castelltort

Objectives:

Exceptional preservation of entire source-to-sink systems in the Southern Pyrenean Foreland basin during Paleocene and Early Eocene provides a unique opportunity to apply novel geochemical tools for quantifying the chemical weathering evolution along the sediment routing system and over a period of time characterized by multiple hyperthermal events (e.g., PETM, ETM2, ETM3). It was recently shown that εNd and εHf decoupling in the detrital clay fraction of sediments (ΔεHf), reflects variations in chemical weathering intensity of the continent. Variations in physical erosion and chemical weathering, tectonically or climatically driven, are also reflected by the nature and relative proportion of clay minerals. We will use an approach combining clay mineralogical analyses with clay Hf and Nd isotope analyses (ΔεHf) on samples distributed along the entire S2S from proximal alluvial plains to basin floor fans, and distributed stratigraphically from the PETM to ETM3, hyperthermals and inter-hyperthermals included. These results will be a natural benchmark for chemical weathering models developed in ESR15.

 

Expected Results:

• first quantification of chemical weathering perturbation due to extreme global climate perturbation,
• response timescale of chemical weathering to rapid climate change,
• generic predictions for global climate impact on continental solute fluxes.

 

Secondments:

• Université Bourgogne Franche Comté (E. Pucéat, P. Pellenard) - Nd/Hf analyses and interpretation (8 months)
• GFZ – Helmholtz Centre Potsdam (J. Braun) - Numerical experiments of weathering during hyperthermals (1 month)