Surface Expressions of Subsurface Sediment Mobilization Rooted into a Gas Hydrate-Rich Cryosphere on Mars.

We report on evidence for fluid circulation in the upper crust of Mars, which could create environments favorable for life and its development. We investigate the nature of the thumbprint terrains covering part of Arcadia Planitia in the Martian northern hemisphere. Our analytic procedure allowed us to (i) hypothesise a potential relationship between these thumbprint terrains and an inferred underground fracture network that extends to where the clathrate-rich cryosphere contacts with the underlying hydrosphere; (ii) support the hypothesis that these thumbprint terrains are made of fine grained loosely packed materials erupted from deep beneath the subsurface mobilized by water; and (iii) date the thumbprint terrains of Arcadia Planitia to ~370 Ma. We conclude that the study area is an area worthy of astrobiological investigation, bringing water and fine grained sediment from depth to the surface for investigation.