Global geochemical cycles

This course is opened to international master students and will be entirely taught in English. It will address the global  geochemical cycles of volatile elements, with a focus on carbon, hydrogen, sulfur and nitrogen cycles. 
 The distribution of these volatile elements in the main Earth’s reservoirs (i.e. mantle, crust, ocean, atmosphere and  biosphere) and the fluxes exchanged between these reservoirs will be presented and discussed.  
 The state-of-the-art methods used by geochemists to determine budgets and fluxes will also be presented. Specifically,  students will be trained to use stable isotope compositions coupled with various geochemical and geophysical  parameters. Students will then discover the laboratories, analytical techniques and mass spectrometers used to  perform these kinds of study. 
 The determination of fluxes exchanged between mantle and surface reservoirs at mid-ocean ridges and subduction  zones will be explored for all selected elements. Students will be trained to solve questions about the extent of  degassing associated to volcanism, or devolatilization related to subduction metamorphism, as well as the isotope  effects associated to these processes. 
 The geochemical budgets and fluxes will finally be used to (i) decipher the long-term evolution of the surface and  mantle compositions, (ii) predict the future of the Earth’s reservoirs, and (iii) extrapolate previous distribution, including  the initial state of the Earth. This last part has strong implications for understanding the formation and early  differentiation of our planet. 

 Master the tools of elemental and isotopic geochemistry. Discover several techniques for measuring  precise isotopic compositions (C, S, N, H) in natural materials. Learn the modelling of various  geochemical processes (melting, crystallization, degassing, devolatilization).

Knowledge in geochemistry, chemistry and geosciences is useful but not mandatory