Fate of mixed CH4-CO2 clathrates in large icy satellites

Within a growing number of icy satellites of the outer solar system, the presence of liquid water has been suggested in a form of subsurface oceans. An intriguing aspect of extra-terrestrial ocean worlds is the influence of high pressure (HP) on their physical state and thermochemical evolution. While a variety of volatile compounds are expected to be present in significant amount in the interior of icy moons, some of these compounds should be stable in the form of gas clathrate hydrates. Clathrate formation and destabilization govern the volatile reservoir and chemical exchange in the interior, affecting astrobiological potential of subsurface oceans. While mixed guest molecules clathrates are expected to be present in the large ocean worlds, almost all previous HP studies have been performed on pure end-member compositions. Herein, we propose to study mixed CH4-CO2 clathrates at relevant HP-LT conditions using in situ X-Ray diffraction in a cryostat-cooled diamond anvil cell.