From the study of ancient sedimenatry rocks, varying mainly from the Archean and Proterozoic ( 3.8 Ga to 600 Ma), we try to reconstruct the chemical evolution of the oceans and the atmosphere, as well as the evolution of living organisms through the history of the Earth . To answer these questions, we couple isotope tools (C, N, S , O, Fe, Δ47 ) often with petrographic and mineralogical obesrvations. The study of Archean paleo-environments is generally conducted in association with our colleagues from the laboratory Géobiosphère Actuelle et Primitive (GAP).
Interpretation of data on ancient rocks can be complex and requires a calibration of our isotope tools by two complementary approaches:
1) study modern analogs to the ancient oceans, such as the Lac Pavin (Massif Central, France) or Dziani Lake (Mayotte). This approach is usually done in collaboration with our colleagues from the Water Geochemistry group (LGE).
2) bacterial cultures in the laboratory and analysis of the products obtained under different physico-chemical conditions, this approach being undertaken in collaboration with our colleagues from GAP.