The quantity of methane in Mars' atmosphere, and the potential mechanism(s) responsible for its production, are still unknown. In order to test viable, abiotic, methangenic processes, we experimentally investigated two possible impact mechanisms for generating methane. In the first suite of experiments, basaltic rocks were impacted at 5kms(-1) and the quantity of gases (CH4, H-2, He, N-2, O-2, Ar and CO2) released by the impacts was measured. In the second suite of experiments, a mixture of water ice, CO2 ice and anhydrous olivine grains was impacted to see if the shock induced rapid serpentinization of the olivine, and thus production of methane. The results of both suites of experiments demonstrate that impacts (at scales achievable in the laboratory) do not give rise to detectably enhanced quantities of methane release above background levels. Supporting hydrocode modelling was also performed to gain insight into the pressures and temperatures occurring during the impact events.
Bibliographical noteThe researchers at Kent acknowledge the STFC, UK for funding this work. Nisha Ramkissoon thanks the UK Space Agency for her support via an Aurora studentship. KM’s work is funded by the UnivEarthS LabEx project of the University of Sorbonne Paris Cité.