Naturally Occurring “Batteries” Fueled Organic Carbon Synthesis on Mars

A high-resolution Transmission Electron Micrograph (scale 50nm) of a grain from a Martian meteorite. Reminiscent of a long dinner fork, the organic carbon layers are found between the intact “tines.” This texture is created when the volcanic minerals of the Martian rock interact with a salty brine and become the anode and cathode of a naturally occurring battery in a corrosion reaction. This reaction would then have enough energy—under certain conditions—to synthesize organic carbon. 

“Revealing the processes by which organic carbon compounds form on Mars has been a matter of tremendous interest for understanding its potential for habitability,” Steele said.

He and his co-authors took a deep dive into the minerology of these three Martian meteorites. Using advanced microscopy and spectroscopy, they were able to determine that the meteorites’ organic compounds were likely created by electrochemical corrosion of minerals in Martian rocks by a surrounding salty liquid brine.

“The discovery that natural systems can essentially form a small corrosion-powered battery that drives electrochemical reactions between minerals and surrounding liquid has major implications for the astrobiology field,” Steele explained.

Credit:  NASA/ Carnegie Institution for Science

A similar process could occur anywhere that igneous rocks are surrounded by brines, including the subsurface oceans of Jupiter’s moon Europa, Saturn’s moon Enceladus, and even some environments here on Earth, particularly early in this planets’ history.

The team included Carnegie’s Pamela Conrad and Jianhua Wang; Liane Benning, Richard Wirth, and Anja Schreiber of the German Research Centre for Geosciences; Sandra Siljeström of the RISE Research Institutes of Sweden; Marc Fries and Francis McCubbin of the NASA Johnson Space Center; Karyn Rogers of Rensselaer Polytechnic Institute; Jen Eigenbrode of NASA’s Goddard Space Flight Center; A. Needham of USRA–Science and Technology Institute; David Kilcoyne of Lawrence Berkeley National Laboratory; and Juan Diego Rodriguez Blanco of University of Leeds.

The paper is dedicated to the memory of Erik Hauri, a Carnegie scientist and co-author on the paper who died in September.