Missions

The objective of the project is to set-up a method to measure the isotopic composition of lithium (7Li/6Li), silica (30Si/28Si) and Ge/Si ratios (optional) in modern and Holocene biogenic silica from Alpine Lake sediments. The goals will be to characterize the isotopic fractionation factor between biogenic silica and water and reconstruct the past isotopic composition of lake waters during the Holocene for quantifying past changes in chemical erosion. The Research Engineer will optimize previously existing methods for extraction and purification of biogenic silica from lake sediments. This will include sieving, heavy liquid separation and chemical leaching methods. The isotopic composition of lithium (7Li/6Li), silica (30Si/28Si) and Ge/Si ratios (optional) will then be measured on the purified biogenic silica sample. Lake water samples isotopic analysis will also be conducted.

Activities

- Laboratory analysis: biogenic silica concentration measurement, extraction and purification.
- Laboratory analysis: Li, Sr, Ge, Si concentration and Li-Si isotope measurements in lake sediments and lake waters
- Data processing and interpretation, writing of scientific articles and presentation of results in international conferences.

Skills

- A PhD (completed) in isotope geochemistry or in a closely related field
- Experience in conducting high quality academic research on sedimentary and/or isotope geochemistry
- Experience in lacustrine environments would be an advantage but is not required.
- The position requires geographical mobility for training in biogenic silica purification and for performing silicon isotope analyses at Durham University (the total Durham secondment duration will be a minimum of 6 weeks and may be extended up to 24 weeks upon the candidate's request).
- Experience in isotope geochemistry, particularly on lithium and silicon isotopes, i.e. working in clean lab environments, column chemistry procedures and mass-spectrometer measurements
- Prior experience in biogenic silica analysis and/or diatom identification will be viewed as an advantage
- A good track record of publishing in peer-reviewed scientific journals
- Experience of decision-making, problem-solving, planning and organizing
- Excellent interpersonal and communication skills

Work Context

This project is fully funded as part of the European Research Council (ERC) Starting Grant “LAKE-SWITCH: Using Lake sediments to reconstruct soil weathering trajectories over the Holocene”. This projects aim at developing and applying new combination of proxy-archives in lake sediments to reconstruct past changes in chemical weathering and soil pedogenesis. The supervisory team will be composed of Dr. Mathieu Dellinger (CNRS researcher, EDYTEM) and Dr. Jotautas Baronas (Durham University). Dr. Pierre Sabatier (MCF, EDYTEM) will also be involved in the supervision of the candidate. The National Center for Scientific Research (CNRS) is a French public research organization with laboratories (and researchers, engineers and support staff) located throughout France. The RI will be integrated into the “Critical Zone” research team at the EDYTEM research unit (“Environments, Dynamics and Mountain Territories”; Le Bourget-du-lac, France) and will be based at two locations: at EDYTEM and at Earth Sciences Department of Durham University (UK). The RI will join the ERC-funded LAKE-SWITCH team (1 PhD and 1 Assistant Engineer) and will interact with international collaborators in the EU and in the UK.
The EDYTEM research unit is part of the University Savoie Mont-Blanc (USMB), one of the major academic institutions in the Auvergne Rhone Alpes region. The Bourget-du-lac campus (where EDYTEM is located) is perfectly located for outdoor activities, close to the Bourget Lake between Chambéry and Aix-les-Bains, with a wide selection of sports, leisure and cultural events offered by the University.
The researcher will also be integrated into the vibrant Environmental Research Group and Durham Geochemistry Centre (DGC) in the Department of Earth Sciences at Durham University, comprised of several principal investigators, technicians, and postgraduate students. DGC is a state-of-the-art analytical facility housing an extensive clean lab and a suite of mass spectrometers, supported by experienced permanent staff. At Durham, the researcher will use geochemical labs to separate and purify lacustrine bSi, followed by SEM, ICP-MS, and MC-ICP-MS analyses.