Martian Chlorobenzene Identified by Curiosity in Yellowknife Bay: Evidence for the Preservation of Organics in a Mudstone on Mars

• Main Authors: Glavin, Daniel, Freissinet, Caroline, Mahaffy, Paul, Miller, K., Eigenbrode, J., Summons, R., Martin, M., Franz, H., Steele, A., Archer, D., Atreya, S., Brinckerhoff, W., Brunner, A., Buch, A., Cabane, Michel, Coll, Patrice, Conrad, P., Des Marais, D., Dworkin, J., Fairén, A., François, P., Grotzinger, J., Kashyap, S., Malespin, C., McAdam, Amy, Ming, D, Navarro-González, R., Pavlov, A., Squyres, S., Stern, J., Sumner, D., Sutter, B., Szopa, Cyril
• Other Authors: NASA Goddard Space Flight Center (GSFC), Massachusetts Institute of Technology (MIT), NASA Johnson Space Center (JSC), NASA, Department of Atmospheric, Oceanic, and Space Sciences Ann Arbor (AOSS), University of Michigan Ann Arbor, University of Michigan System-University of Michigan System, Ecole Centrale Paris, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center (ARC), Centro de Astrobiologia Madrid (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas Madrid (CSIC), Cornell University New York, California Institute of Technology (CALTECH), University of Massachusetts Amherst (UMass Amherst), University of Massachusetts System (UMASS), Universidad Nacional Autónoma de México (UNAM), University of California Davis (UC Davis), University of California, Jacobs Technology ESCG
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology; [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]; Yellowknife; Yellowknife Bay
• Online Access: https://hal.archives-ouvertes.fr/hal-01815498; https://hal.archives-ouvertes.fr/hal-01815498/document; https://hal.archives-ouvertes.fr/hal-01815498/file/1178.pdf

International audience The Sample Analysis at Mars (SAM) instrument on the Curiosity rover is designed to determine the inventory of organic and inorganic volatiles thermally evolved from solid samples using a combination of evolved gas analysis (EGA), gas chromatography mass spectrometry (GCMS), and tunable laser spectroscopy [1]. The first sample analyzed by SAM at the Rocknest (RN) aeolian deposit revealed chlorohydrocarbons derived primarily from reactions between a martian oxychlorine phase (e.g. perchlorate) and terrestrial carbon from N-methyl-N-(tert-butyl-dimethylsilyl)trifluoroacetamide (MTBSTFA) vapor present in the SAM instrument background [2]. No conclusive evidence for martian chlorohydrocarbons in the RN sand was found [2]. After RN, Curiosity trav-eled to Yellowknife Bay and drilled two holes separated by 2.75 m designated John Klein (JK) and Cumber-land (CB). Analyses of JK and CB by both SAM and the CheMin x-ray diffraction instrument revealed a mudstone (called Sheepbed) consisting of ~20 wt% smectite clays [3], which on Earth are known to aid the concentration and preservation of organic matter. Last year at LPSC we reported elevated abundances of chlorobenzene (CBZ) and a more diverse suite of chlorinated hydrocarbons including dichloroalkanes in CB compared to RN, suggesting that martian or mete-oritic organic compounds may be preserved in the mudstone [4]. Here we present SAM data from additional analyses of the CB sample and of Confidence Hills (CH), another drill sample collected at the base of Mt. Sharp. This new SAM data along with supporting laboratory analog experiments indicate that most of the chlorobenzene detected in CB is derived from martian organic matter preserved in the mudstone [5].