Biomarker Analysis of Samples Visually Identified as Microbial in the Eocene Green River Formation: An Analogue for Mars

摘要

One of the major exploration targets for current and future Mars missions are lithofacies suggestive of biotic activity. Although such lithofacies are not confirmation of biotic activity, they provide a way to identify samples for further analyses. To test the efficacy of this approach, we identified carbonate samples from the Eocene Green River Formation as microbial or non-microbial based on the macroscale morphology of their laminations. These samples were then crushed and analyzed by gas chromatography/mass spectroscopy (GC/MS) to determine their lipid biomarker composition. GC/MS analysis revealed that carbonates visually identified as microbial contained a higher concentration of more diverse biomarkers than those identified as non-microbial, suggesting that this could be a viable detection strategy for selecting samples for further analysis or caching on Mars. Key Words: Life detectionBiomarkersStromatolitesGreen River Formation. Astrobiology 15, 770-775.