Postdoc in geochemical modeling of the Critical Zone (M/F)

Job Description

Missions

Lake sediments are valuable archives for reconstructing past environmental conditions at the catchment scale. In recent years, the isotopes of the trace element lithium (Li) in lake detrital sediments have emerged as powerful tracers of soil dynamics over centennial to millennial timescales. However, the interpretation of these signals remains limited by the lack of an appropriate process-based modeling framework capable of providing quantitative constraints on the history of soil formation, erosion, pH, and drainage.
The objectives of this project are to:
a) develop a multi-component reactive transport modeling framework embedding the lithium isotope system; and
b) apply this framework to interpret Holocene geochemical and Li isotope records from major lake archives in the European Alps.

Activity

- Develop a 1D reactive transport model (RTM) incorporating Li isotopes using the CrunchTope software, representing weathering processes typical of Alpine soils
- Contribute to mineralogical and geochemical analyses of existing bedrock and soil samples collected along soil chronosequences (multi-millenial scale) in modern glacier retreat areas in the French Alps
- Use these data to constrain RTM simulation parameters
- Conduct a detailed sensitivity analysis of RTM outputs (geochemical composition and Li isotopic signatures of eroded solids and drained fluids) to assess the effects of changing erosion, variations in drainage rates, and shifts in pH
- Apply inverse modeling of existing lake sedimentary archive data using the RTM framework to quantitatively reconstruct past changes in erosion, drainage, and pH at the scale of major Alpine catchments in France

Your Profil

Skills

- PhD in Earth Sciences or a closely related field
- Demonstrated experience in high-quality academic research involving numerical modeling
- Experience in isotopic geochemistry and/or sedimentology is desirable but not required
- Strong publication record in peer-reviewed scientific journals
- Proven capacity for independent decision-making, problem-solving, planning, and organization
- Excellent interpersonal and communication skills.

Your Work Environment

This project is fully funded by the ERC Starting Grant “LAKE-SWITCH: Using lake sediments to reconstruct soil weathering trajectories during the Holocene.” The supervisory team includes Mathieu Dellinger (CNRS, EDYTEM Chambéry), Julien Bouchez (CNRS, IPG Paris), and Jennifer Druhan (University of Illinois Urbana-Champaign and IPGP).

The Centre National de la Recherche Scientifique (CNRS) is a major public research institution with laboratories distributed across France. EDYTEM is part of Université Savoie Mont-Blanc, a leading academic institution in the Auvergne-Rhône-Alpes region. Its Bourget-du-Lac campus is ideally located near Lake Bourget, between Chambéry and Aix-les-Bains, offering excellent opportunities for outdoor activities alongside a rich program of sports and cultural events. The Institut de Physique du Globe de Paris, a world-renowned geosciences institution affiliated with CNRS and a component of Université Paris Cité, brings together more than 500 researchers, engineers, and staff. Its research spans the Earth and planetary sciences, from the core to surface environments, combining observation, experimentation, and modeling. The IPGP campus is located in the heart of Paris, offering all the advantages of a vibrant international capital.

Constraints and risks

The successful candidate will be affiliated with both EDYTEM (“Environments, Dynamics and Mountain Territories”; Le Bourget-du-Lac, France), where they will join the “Critical Zone” research team, and Institut de Physique du Globe de Paris, as part of the G2E (Geochemistry of Outer Layers) group. As such, the position requires geographical mobility between the two host institutions. The successful candidate will have flexibility in choosing their primary place of work.

Compensation and benefits

Compensation

From €3,041.58 gross per month, depending on experience and the current CNRS pay scale

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions