Vision and Voyages for Planetary Science in the - Solar System ...

developed hydrothermal systems and hot springs that might have sustained locally habitable
environments. 18
Since ~3.5 billion years ago, rates of weathering and erosion appear to have been very low and
the most characteristic fluvial features are outflow channels formed by the catastrophic release of nearsurface
water. 19 Groundwater is likely to be stable at greater depths and it might sustain habitable
environments. In all epochs, the combination of volcanism and water-rich conditions might have
sustained hydrothermal systems in which life could have thrived.
FIGURE 6.3 Diverse mineralogy observed with CRISM data formed by water-related processes and
indicative of potentially habitable environments. SOURCE: B.L. Ehlmann and J.F. Mustard, Stratigraphy
of the Nili Fossae and the Jezero Crater Watershed: A Reference Section for the Martian Clay Cycle,
presentation at the First International Conference on Mars Sedimentology and Stratigraphy, April 19-21,
2010, El Paso, Texas, #6064, Lunar and Planetary Science Conference 2010. Lunar and Planetary
Institute.
Important Questions
Some important questions concerning the past and present habitability of Mars include the
following:
• Which accessible sites on Mars offer the greatest potential for having supported life in the
past? How did the major factors that determine habitability—duration and activity of liquid water, energy
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