Atmospheric origins of perchlorate on Mars and in the Atacama

doi:doi:10.1029/2009JE003425

Abstract

Cited By (7)

Abstract

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115, E00E11, 15 PP., 2010
doi:10.1029/2009JE003425

Atmospheric origins of perchlorate on Mars and in the Atacama

D. C. Catling

Department of Earth and Space Sciences, Astrobiology Program, University of Washington, Seattle, Washington, USA

Department of Earth Sciences, University of Bristol, Bristol, UK

M. W. Claire

Department of Astronomy, Astrobiology Program, University of Washington, Seattle, Washington, USA

K. J. Zahnle

NASA Ames Research Center, Moffet Field, California, USA

R. C. Quinn

NASA Ames Research Center, Moffet Field, California, USA

SETI Institute, Moffett Field, California, USA

B. C. Clark

Space Science Institute, Boulder, Colorado, USA

M. H. Hecht

JPL, California Institute of Technology, Pasadena, California, USA

S. Kounaves

Department of Chemistry, Tufts University, Medford, Massachusetts, USA

Isotopic studies indicate that natural perchlorate is produced on Earth in arid environments by the oxidation of chlorine species through pathways involving ozone or its photochemical products. With this analogy, we propose that the arid environment on Mars may have given rise to perchlorate through the action of atmospheric oxidants. A variety of hypothetical pathways can be proposed including photochemical reactions, electrostatic discharge, and gas-solid reactions. Because perchlorate-rich deposits in the Atacama desert are closest in abundance to perchlorate measured at NASA's Phoenix Lander site, we made a preliminary study of the means to produce Atacama perchlorate to help shed light on the origin of Martian perchlorate. We investigated gas phase pathways using a 1-D photochemical model. We found that perchlorate can be produced in sufficient quantities to explain the abundance of perchlorate in the Atacama from a proposed gas phase oxidation of chlorine volatiles to perchloric acid. The feasibility of gas phase production for the Atacama provides justification for future investigations of gas phase photochemistry as a possible source for Martian perchlorate.

Received 7 May 2009; accepted 18 September 2009; published 22 January 2010.

Citation: Catling, D. C., M. W. Claire, K. J. Zahnle, R. C. Quinn, B. C. Clark, M. H. Hecht, and S. Kounaves (2010), Atmospheric origins of perchlorate on Mars and in the Atacama, J. Geophys. Res., 115, E00E11, doi:10.1029/2009JE003425.

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