Abstract. The search for life on Mars has recently focused on its potential survival in deep (>2 km) subpermafrost aquifers where anaerobic bacteria, similar to those found in deep subsurface ecosystems on Earth, may have survived in an environment that has remained stable for billions of years. An anticipated by-product of this biological activity is methane. The detection of large deposits of methane gas and hydrate in the Martian cryosphere, or as emissions from deep fracture zones, would provide persuasive evidence of indigenous life and confirm the presence of a valuable in situ resource for use by future human explorers.
IntroductionWith an average surface temperature of -200 K, a CO2 atmosphere with a surface pressure of-6 mbar, and a high incident flux of UVB, the present Martian surface environment is hostile to life as we know it. However, there is abundant The depth to which significant porosity, permeability, and water persist on Mars is unknown. However, in light of the considerable extent to which impacts, volcanism, tectonics, and the presence of abundant water have affected the evolution of its surface, it is likely that the gross physical and hydraulic properties of the Martian crust will closely resemble those found on Earth, appropriately scaled to reflect the gravitationally induced differences in lithostatic pressure at a given depth. This suggests that the porosity and permeability conditions 4165