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Indigenous Organic Molecular Biosignatures are Detectable via ToF-SIMS of a Kerogen-rich Jurassic Clay

Publication Type
Conference Paper
Journal Name
AGU Astrobiology Science Conference Proceedings
Book Title
Proceedings of the 2022 Astrobiology Science Conference (AbSciCon22)
Publication Date
Page Numbers
1 to 1
Publisher Location
District of Columbia, United States of America
Conference Name
2022 Astrobiology Science Conference (AbSciCon22)
Conference Location
Atlanta, Georgia, United States of America
Conference Sponsor
NASA, AGU
Conference Date
-

Time of Flight - Secondary Ion Mass Spectrometry (ToF-SIMS) is a Mass Spectrometry (MS) imaging technique that can be used in conjunction with traditional organic geochemical analysis (organics extracted from a crushed sample) in order to determine how molecules observed in the organic extracts were incorporated into a particular rock sample. This type of analysis may be used on samples collected as part of Mars Sample Return (MSR) in order to determine if potential organic compounds were indigenous to Mars or whether they are contaminants.

Here we show that Organic Molecular Biosignatures (OMBs including steranes and derivatives of a carotenoid) are detectable via ToF-SIMS within a Jurassic mudstone. The OMBs are only detectable in areas with high organic carbon, likely kerogen, indicating that they are indigenous to the rock. We conclude that: I) Indigenous OMBs are detectable via ToF-SIMS in ancient, kerogen-rich samples; II) the presence of a molecular ion strengthens the interpretation of ToF-SIMS spectra of complex natural material, and III) the spatial co-occurrence of kerogen and potentially indigenous OMBs in ancient sediments is a valid test of their character. These conclusions are directly relevant to MSR sample selection as well as the analysis of MSR samples upon return.