Detecting Kerogen as a Biosignature Using Co-located UV Time-Gated Raman and Fuorescence Spectroscopy
Abstract
The Mars 2020 mission will analyze samples in situ and identify any that could have preserved biosignatures in ancient habitable environments for later return to Earth. Highest-priority targeted samples include aqueously formed sedimentary lithologies containing fossil biosignatures as aromatic carbon (kerogen). In this study, we analyze non-extracted, naturally preserved kerogen in a diverse suite of realistic Mars analogs using combined UV excitation time-gated (UV-TG) Raman and laser-induced fluorescence spectroscopy. We interrogated kerogen and its host matrix in samples to: (1) explore the capabilities of UV-TG Raman and fluorescence spectroscopy for detecting kerogen in high-priority targets in the search for a Martian fossil record; (2) assess the effectiveness of time-gating and UV laser wavelength in reducing fluorescence; and (3) identify sample-specific issues which could challenge rover-based identifications of kerogen using UV-TG Raman spectroscopy. We found that ungated UV Raman is suited to identify diagnostic kerogen Raman bands without interfering fluorescence and that fluorescence features indicating kerogen are detectable. These data highlight the value of using both co-located Raman and fluorescence data sets together to strengthen the confidence of kerogen detection as a potential biosignature and are obtainable by SHERLOC onboard Mars 2020.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.P53D2666S
- Keywords:
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- 5210 Planetary atmospheres;
- clouds;
- and hazes;
- PLANETARY SCIENCES: ASTROBIOLOGY;
- 5215 Origin of life;
- PLANETARY SCIENCES: ASTROBIOLOGY;
- 6099 General or miscellaneous;
- PLANETARY SCIENCES: COMETS AND SMALL BODIES;
- 6299 General or miscellaneous;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS