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GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L24102, doi:10.1029/2007GL031184, 2007

Search for past life on Mars: Physical and chemical characterization of minerals of biotic and abiotic origin: 2. Aragonite

F. Stalport

Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR 7583, CNRS, Université Paris VII and Paris XII, Créteil, France


P. Coll

Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR 7583, CNRS, Université Paris VII and Paris XII, Créteil, France


C. Szopa

Service d'Aéronomie, L'Institut Pierre Simon Laplace, Université Pierre et Marie Curie-Paris VI, UMR 7620, CNRS, Verrières-le-Buisson, France


A. Person

Laboratoire de Biominéralisations et Paléoenvironnements, Université Pierre et Marie Curie-Paris VI, Paris, France


R. Navarro-González

Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR 7583, CNRS, Université Paris VII and Paris XII, Créteil, France


M. Cabane

Service d'Aéronomie, L'Institut Pierre Simon Laplace, Université Pierre et Marie Curie-Paris VI, UMR 7620, CNRS, Verrières-le-Buisson, France


P. Ausset

Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR 7583, CNRS, Université Paris VII and Paris XII, Créteil, France


M. J. Vaulay

Interfaces, Traitements, Organisation et Dynamique des Systemes, Université Paris VII, Paris, France


Abstract

One of the major objectives of the future Martian surface probes will be to reveal a past or present biological activity. We propose that biominerals could have recorded such an activity at Mars, and thus could be interesting targets for these missions. Therefore, we try to find a method capable to discriminate biominerals from their geochemical counterparts. With this aim, various terrestrial aragonites of biotic and abiotic origins were studied as reference minerals, because they could have also been produced at Mars. Their thermal properties were studied with differential thermal analysis, and then compared. The results show that biotic aragonites thermally decompose at temperatures at least 20°C lower than the temperatures of decomposition of abiotic aragonites. Therefore, the temperatures of thermal degradation of such biominerals could be a relevant parameter to find a past biological activity at Mars, and differential thermal analysis could be useful for situ astrobiological exploration of Mars.

Received 29 June 2007; accepted 13 November 2007; published 19 December 2007.

Keywords: Mars; life; biomineralization; carbonates.

Index Terms: 6225 Planetary Sciences: Solar System Objects: Mars; 0456 Biogeosciences: Life in extreme environments.

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Citation: Stalport, F., P. Coll, C. Szopa, A. Person, R. Navarro-González, M. Cabane, P. Ausset, and M. J. Vaulay (2007), Search for past life on Mars: Physical and chemical characterization of minerals of biotic and abiotic origin: 2. Aragonite, Geophys. Res. Lett., 34, L24102, doi:10.1029/2007GL031184.