In situ detection of boron by ChemCam on Mars

Patrick J. Gasda , Ethan B. Haldeman , Roger C. Wiens , William Rapin , Thomas F. Bristow , John C. Bridges , Susanne P. Schwenzer , Benton Clark , Kenneth Herkenhoff , Jens Frydenvang , Nina L. Lanza , Sylvestre Maurice (1) , Samuel Clegg , Dorothea M. Delapp , Veronica L. Sanford , Madeleine R. Bodine , Rhonda Mcinroy

1 CNES - Centre National d’Études Spatiales [Paris]

We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels <0.05 wt % B by the NASA Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater.

Keywords: boron; Mars habitability; ChemCam; prebiotic chemistry; Mars groundwater; NASA Curiosity rover

Domains: Sciences of the Universe [physics]

Patrick J. Gasda, Ethan B. Haldeman, Roger C. Wiens, William Rapin, Thomas F. Bristow, et al.. In situ detection of boron by ChemCam on Mars. Geophysical Research Letters, 2017, 44, pp.8739-8748. ⟨10.1002/2017GL074480⟩. ⟨insu-03676956⟩