LAVA FLOWS AND INTRUSION EFFECTS ON THE THERMAL VIABILITY OF VOLATILE LAYERS

Both MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) and SHARAD (Shallow Radar sounder) have identified subsurface reflectors on Mars that are consistent with the presence of buried water, primarily as ice, but including at least one possible liquid water locale. Geomorphologic evidence (lobate debris aprons, for example) are also consistent with the presence of subsurface volatiles on Mars. Mars also displays abundant evidence of volcanism. It is likely that lava (or magma) and water have interacted on Mars in the past. Being able to constrain these magma-water interactions, and understand their behaviors, could provide insight into both the volcanic and volatiles histories of Mars.

We model the thermal long term viability of solid and pore-space-filling H₂O and CO₂ ices in the martian near subsurface and their thermal response to volcanic flows and intrusions. We consider different thicknesses of overlying sediments, overlying sediments and lava flows, and intrusions below the volatiles. We use multiphysics (COMSOL) software to obtain 2-D and limited 3-D thermal solutions for the stacked materials, and to track phase changes and pressure fields within the porous layers.

We find that 2-D and 3-D models differ from prior 1-D models in that tracking the more complex thermal solution better allows for considering the time-dependence of thermal solutions. This allows better insight into volatile layer longevity as a stand-alone problem and in potential lava-water interaction conditions.