Exobiological implications of potential sedimentary deposits on Mars

One of main objectives of Mars exploration in the 21st century is to search for evidence of present or ancient life. Sedimentary processes are important on the Martian surface. However, styles of Martian sedimentation can be dierent from its terrestrial counterpart in some aspects because of the relatively stable Martian crust and the lack of a continuous and active surface hydrological cycle. Certain types of sedimentary deposits on Earth are closely linked to biological activities, and searching for such deposits on Mars can potentially enhance the chance of nding life or evidence of ancient life on the planet. A wide range of hypothesized siliciclastic and non-siliciclastic sedimentary deposits on Mars are of particular interest for the future exobiological exploration. Searching the substrate of sedimentary deposits is the preferred strategy because it is dicult to preserve organic matter or geochemical evidence of biological activity in the photochemically active and oxidizing surface environment of Mars.