Current Projects
Early atmosphere and seawater – Multiple sulfur isotopes analysis of sulfate and sulfide minerals in Archean paleosols, terrigeneous sediments and hydrothermal systems with the aim of better understanding the chemistry and dynamics of the Archean atmosphere and terrestrial overprints. Other proxies involve fluid inclusions present in hydrothermal systems, which can preserve pristine signatures of Archean seawater and atmosphere composition.
Biogeochemical cycling of marine nutrients and their impact on life evolution. Collaborative geochemical exploration of microbially-mediated cycling of carbon, nitrogen, sulfur, and metals as expressed in their abundances, redox state and isotopic compositions, with the aim of establishing how the levels of trace nutrients in the oceans evolved through time as a consequence of changing redox conditions, and how this evolutionary trend may have affected/delayed the evolution of life.
Early ecosystems and metabolic functions. Image and analyze the abundance, distribution and speciation of sulfur, arsenic and metals (from Fe to U) in living and ancient microbiological mats (stromatolites) and micro-organisms (microfossils) using the new generation of scanning X-ray nanoprobe emerging at synchrotron facilities (e.g., Nanoscopium beamline). This in turn provides data by which to tie physiological inference from trace metal distribution and speciation patterns directly to the fossil biomass, providing a means to understand the interplay between microbial metabolisms and bio-availability of trace metals and to distinguish true bio-geochemical proxies from artefacts in the Precambrian Record.
Archean Geodynamics. Investigate the mechanisms of crust formation on early Earth. A key question of current interest is how and when subduction initiated as it is intrinsically connected to the secular evolution of the atmosphere, through sea-level changes caused by ocean-mantle interaction, and from then on to the enrichment and recycling of key elements for life in the progressively emerging continental masses.
FUNDING SOURCES
ANR-eLIFE1
LABEX UnivEarthS- Frontier Project “Earth as a Living Planet: From Early Ages to Present dynamics
Programme National de Planétologie
FAPESP project, the co-evolution of life and oxygen: a South American perspective