Haematite–water system on Mars and its possible role in chemical evolution
AbstractRecent findings on the presence of water on Mars (Baker, V.R. (2006). Geomorphological evidence for water on Mars. Elements2(3), 139–143; DeJong, E. (2006). Geological evidence of the presence of water on Mars. Abstracts from the 40th Western Regional Meeting of the American Chemical Society, Anaheim, CA, January, 2006, pp. 22–25. American Chemical Society, Washington, DC; McSween, H.Y. Jr. (2006). Water on Mars. Elements2(3), 135–137; Mitrofanov, I.G. (2005). Water explorations on Mars. Priroda9, 34–43) strongly suggest that there existed a period of chemical evolution eventually leading to life processes on primitive Mars (Kanavarioti, A. & Maneinelli, R.L. (1990). Could organic matter have been preserved on Mars for 3.5 billion years. Icarus84, 196–202). Owing to the adverse conditions, it is quite likely that the process of chemical evolution would have been suppressed and any living organisms that formed would have become extinct over time on Mars. The presence of water as a necessity for the survival of living organisms and the presence of grey haematite, originated under aqueous conditions, have led us to investigate the possible role of haematite in the chemical evolution on Mars. Our observations suggest that iron oxide hydroxide (FeOOH), a precursor of haematite, has a much higher binding affinity towards ribose nucleotides (the building blocks of RNA) than the haematite itself. This would mean that during the process of haematite formation, especially through the probable process of Fe3+ hydrolysis by aqueous ammonia, the precursors of haematite might have played a significant role in the processes leading to chemical evolution and the possible origin of life on Mars.
