Organic synthesis on Mars by electrochemical reduction of CO<sub>2</sub>.

Steele, A; Benning, L G; Wirth, R; Siljeström, S; Fries, M D; Hauri, E; Conrad, P G; Rogers, K et al. · Sci Adv · 2018

basic_science · Level V

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Abstract

The sources and nature of organic carbon on Mars have been a subject of intense research. Steele <i>et al.</i> (2012) showed that 10 martian meteorites contain macromolecular carbon phases contained within pyroxene- and olivine-hosted melt inclusions. Here, we show that martian meteorites Tissint, Nakhla, and NWA 1950 have an inventory of organic carbon species associated with fluid-mineral reactions that are remarkably consistent with those detected by the Mars Science Laboratory (MSL) mission. We advance the hypothesis that interactions among spinel-group minerals, sulfides, and a brine enable the electrochemical reduction of aqueous CO<sub>2</sub> to organic molecules. Although documented here in martian samples, a similar process likely occurs wherever igneous rocks containing spinel-group minerals and/or sulfides encounter brines.