Two small depressions on Mars found to be rich in minerals formed by water could have been places able to support life relatively recently in the planet's history. These findings were published October 1, 2011, in the journal Geology. The team, led by Catherine Weitz of the Planetary Science Institute, studied layered outcrops at the western region of the huge Valles Marineris canyon system.
Many ancient clay-rich rocks have been found on Mars in recent years. What is interesting about this study at Noctis Labyrinthus is that we see alternating rock layers of clays and sulfates, including some clay outcrops as young as 2-3 billion years old, rather than the more common 4 billion year old clay rocks. Dr. Weitz reports, "This indicates a different water environment in these troughs or depressions relative to what was happening elsewhere on Mars."
Each trough probably experienced multiple water-infilling episodes at variable pH levels that deposited clays under neutral to basic conditions and sulfate minerals under acidic conditions. This dynamic geochemical environment indicates that these two troughs are unique and could have provided a more habitable region on Mars at a time when drier conditions dominated the surface.
The team and I mapped hydrated minerals within each trough using high-resolution images from the High Resolution Imaging Science Experiment (HiRISE) camera and hyperspectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the Mars Reconnaissance Orbiter (MRO) spacecraft, combined with Digital Terrain Models (DTMs) to determine elevations and view geometric relationships between units.
This area would be a fantastic place to investigate with a rover, but the rugged terrain would be challenging for both landing and driving. I'm continuing to investigate sites of interesting aqueous mineralogy on Mars in order to search for possible sites where life may have been possible.
Learn more about Janice and her research in her Q&A, Mars: Back through the Looking Glass."