Characterization and Development of a Mineralogical and Chemical Analog of Cumberland Drill Sample Sediments for Organic Molecule Identification in Evolved Gas Analysis Experiments. - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Communication Dans Un Congrès Année : 2018

Characterization and Development of a Mineralogical and Chemical Analog of Cumberland Drill Sample Sediments for Organic Molecule Identification in Evolved Gas Analysis Experiments.

Résumé

The first evidence of organic molecules indigenous to the surface of Mars was captured by the Sample Analysis at Mars (SAM) instrument aboard the Mars Science Laboratory (MSL) Curiosity rover. A Gas Chromatography-Mass Spectrometry (GCMS) coupled to an Evolved Gas Analysis (EGA) experiment identified a chlorobenzene release during pyrolysis of the sediments from the Cumberland drill sample from the Sheepbed mudstone unit of Gale Crater. In order to better understand the nature of the precursor organic molecules and oxychlorine species that were likely to have reacted together during the pyrolysis of the Cumberland sample in the SAM oven, we have developed a mineralogical and chemical analog material. This Cumberland Analog (CBA) is based on mineral abundances determined by the Chemistry and Mineralogy (CheMin) instrument that employs X-Ray Diffraction (XRD) for identification and relative abundance of crystalline minerals. The CBA mixture includes fourteen minerals that were individually characterized by XRD, X-Ray Fluorescence (XRF) and GCMS. These analyses were also used to account for any trace mineral and organic components, including cyclic hydrocarbons and sulfur compounds. The individual mineral components and the mixture were also pyrolyzed to understand and identify the organic background present in an EGA analysis. CBA includes several key components such as a fine-grained palagonite material to represent the unknown x-ray amorphous portion of the sample, and griffithite, a close terrestrial analog to the Fe-smectite found in the Cumberland drill sample. CBA has been used for a number of SAM-like experiments on breadboard and testbed instruments. CBA will also be analyzed with models of the ChemCam (MSL) and SuperCam (Mars 2020) instruments, which are also sensitive to hydrogen content and carbon-bearing species. These analyses can substitute different trace perchlorate minerals and organic substituents to reconstruct the chlorobenzene release from Cumberland, increasing our understanding of the organic molecules preserved in martian sediments. CBA is also available for use by the wider Mars science community to support further investigation of data collected by MSL.
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Dates et versions

insu-04425928 , version 1 (30-01-2024)

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H. Graham, J. C. Stern, Caroline Freissinet, A. Mcadam, C. A. Knudson, et al.. Characterization and Development of a Mineralogical and Chemical Analog of Cumberland Drill Sample Sediments for Organic Molecule Identification in Evolved Gas Analysis Experiments.. American Geophysical Union, Fall Meeting 2018, Dec 2018, Washington (Etats-unis), United States. pp.abstract #P51C-15B. ⟨insu-04425928⟩
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