HR: 08:30h
AN: P41D-03    [Abstracts]
TI: Limitations on Detection of Low Levels on Organics in Mars-Like Soils using Pyrolysis GCMS: Implications for the Viking Lander Results
AU: * Navarro-Gonzalez, R
EM: navarro@nucleares.unam.mx
AF: Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Apartado Postal 70-543, Mexico City, DF 04510 Mexico
AU: Navarro, K F
EM: rnavarro94@prodigy.net
AF: Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Apartado Postal 70-543, Mexico City, DF 04510 Mexico
AU: de la Rosa, J
EM: delarosa@nucleares.unam.mx
AF: Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Apartado Postal 70-543, Mexico City, DF 04510 Mexico
AU: Molina, P
EM: paolam@nucleares.unam.mx
AF: Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Apartado Postal 70-543, Mexico City, DF 04510 Mexico
AU: Iñiguez, E
EM: iniguez@nucleares.unam.mx
AF: Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Apartado Postal 70-543, Mexico City, DF 04510 Mexico
AU: Miranda, L D
EM: lmiranda@servidor.unam.mx
AF: Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Mexico City, DF 04510 Mexico
AU: Morales, P
EM: pmorales@geologia.unam.mx
AF: Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la Investigación, Ciudad Universitaria, Ciudad Universitaria, Apartado Postal 70-296, Mexico City, DF 04510 Mexico
AU: Cienfuegos, E
EM: edithca@servidor.unam.mx
AF: Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la Investigación, Ciudad Universitaria, Ciudad Universitaria, Apartado Postal 70-296, Mexico City, DF 04510 Mexico
AU: Coll, P
EM: pcoll@lisa.univ-paris12.fr
AF: Laboratoire Inter-Universitaire des Systèmes Atmosphériques, UMR CNRS 7583, Universités Paris 12 & Paris 7, CMC, 61 Avenue du Général de Gaulle, Creteil, F94010 France
AU: Raulin, F
EM: raulin@lisa.univ-paris12.fr
AF: Laboratoire Inter-Universitaire des Systèmes Atmosphériques, UMR CNRS 7583, Universités Paris 12 & Paris 7, CMC, 61 Avenue du Général de Gaulle, Creteil, F94010 France
AU: Amils, R
EM: ramils@cbm.uam.es
AF: Centro de Astrobiología (CSIC-INTA), Torrejón de Ardoz, Madrid, 28850 Spain
AU: McKay, C P
EM: cmckay@mail.arc.nasa.gov
AF: Space Science Division, NASA-Ames Research Center, Building 245 Room 212 // M.S. 245-3, Moffett Field, CA 94035 United States
AB: The non-detection of organics by the Viking pyrolysis gas chromatography mass spectrometry (pyr-GC-MS) experiment suggested chemical rather than biological interpretations for the reactivity of the Martian soil. Here we report that pyr-GC-MS may be blind to low levels of organics on Mars. A comparison between pyr-GC-MS and total organics has been conducted for a variety of Mars analog soils. In the Antarctic dry valleys and the Atacama Desert we find 10-90 μg of refractory or graphitic carbon per gram of soil which would have been undetectable by the Viking pyr-GC-MS. In iron-contain soils (jarosites from Rio Tinto and Panoche Valley) and the Mars simulant (palogonite), oxidation of the organic material to carbon dioxide (CO₂) by iron oxides and/or their salts drastically attenuates the detection of organics. The release of 50-700 ppm of CO₂ and of 0.01-1.0% of water vapour (H₂O) by pyr-GC-MS in the Viking analysis may indicate that an oxidation of organic material took placed. Therefore, the Martian surface could have several orders of magnitude more organics than previously thought. Because of the simplicity of sample handling, pyr-GC-MS is still considered the standard method for organic detection on future Mars missions. Nevertheless, the design of future organic instruments for Mars should include other methods in order to be able to detect extinct and/or extant life.
DE: 0424 Biosignatures and proxies
DE: 0456 Life in extreme environments
DE: 1060 Planetary geochemistry (5405, 5410, 5704, 5709, 6005, 6008)
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: Fall Meeting 2005