Mawrth Vallis is a valley north of the equator of Mars (22.3°N, 343.5°E). The name ‘Mawrth’ means ‘Mars’ in Welsh.
note: in the coming days we will dedicate a Picture of the Day story to the name-giving on Mars.
All the other landing sites that were under consideration for Curiosity are located south of the equator, but the fact that Mawrth Vallis is an ancient water outflow rich in light-coloured clays. Mawrth Vallis is one of the oldest valleys on Mars. Mawrth Vallis is in the middle of a region that has always been of great interest to scientists. It sits on the boundery of the much higher south of Mars and the lowlands of the north of Mars.
At Mawrth Vallis we find layered cliffs that have been imaged and probed by several satellites. The European Space Agency’s Mars Express orbiter identified the presence of phyllosilicate (clay) minerals which form only if water is available with its OMEGA spectrometer. NASA’s Mars Reconnaissance Orbiter (MRO) then identified aluminium-rich and iron-rich clays in this old river bed. Among the clays recently discovered by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of MRO are montmorillonite and kaolinite, and nontronite. Microscopic life can be found in such clays on Earth, which seems to promise the possibility of finding (ancient) life on Mars in them as well.
Today’s image shows Mawrth Vallis snaking as it descends from the highlands of Arabia Terra in the right background. The dark rough areas in the foreground contain deposits of weathered clays discussed above. Just outside the rim of the large crater visible in part on the right. This view looks southeast and has a 1.5x vertical exaggeration.
Credit: NASA/JPL/Arizona State University, R. Luk.