Séminaire "Experimental study of serpentinization and abiotic CH4 production in martian conditions" par Valentin Fortier (Université Libre de Bruxelles)

Lundi 14 Novembre 2022, 14:00 - 15:00
par Stéphanie BEAUNAY


Abstract : Methane is still a debate subject on Mars regarding all of its aspect: production, removal, link with a biological activity, and even detection with the disagreement between rover and orbiter. In my work, I consider the hypothesis of a current production through abiotic processes, and more precisely by FTT reactions: processes using metallic catalyst to sustain H2 reaction with a carbon source to form hydrocarbons and water.

In this frame, we consider the required H2 to be coming from another abiotic reaction named serpentinization: the oxidation of Fe2+ bearing minerals (such as olivine and pyroxene) by liquid water that will form serpentines, Fe3+ bearing minerals, other secondary minerals, and the H2.
Thanks to serpentines detection on the surface of Mars, we know that serpentinization happened, meaning the geology is suiting, and that nowadays the only missing key seems to be liquid water. But we also know that we have conditions to have liquid water in the martian underground, meaning that we have the conditions for serpentinization to happen right now in the martian sub-surface.
      In our work, we have done experiments to test serpentinization and methanation H2 and CH4 production capacity with a martian like material in martian underground conditions. To do so, we first developed for our experiments a martian meteorite shergottite analogue using pure terrestrial minerals.
We then developed a first experimental protocol focusing on water-rock reactions for serpentinization, where we checked the evolution of gas and ions concentrations in the liquid phase during the experiments. At the end of the experiment, we retrieved the solid phase and analyzed it to characterize the mineral phases produced and consumed.
The second experimental setup is focusing on gas-rock interactions for FTT reactions. We used our analog and various other similar samples, and we checked which gas were used and produced during the experiments.