Sedimentary Organics in Glen Torridon, Gale Crater, Mars: Results from the SAM Instrument Suite and Supporting Laboratory Analyses

Maeva Millan (1, 2, 3) , Amy J. Williams (4) , Amy C Mcadam (3) , Jennifer L. Eigenbrode (3) , Andrew Steele (5) , Caroline Freissinet (1) , Daniel P. Glavin (3) , Cyril Szopa (1) , Arnaud Buch (6) , Roger E. Summons (7) , James M. T. Lewis (3, 8, 9) , Gregory M. Wong (10) , Christopher H. House (10) , Brad Sutter (11) , Ophélie McIntosh (1) , Alexander B. Bryk (12) , Heather B. Franz (3) , Chad I. Pozarycki (13, 3) , Jennifer C. Stern (3) , Rafael Navarro-González (14) , P. Douglas Archer (11) , Valerie Fox (13) , Kristen A. Bennett (15) , Samuel Teinturier (3, 16) , Charles Malespin (3) , Sarah Johnson (2) , Paul R. Mahaffy (3)

1 PLANETO - LATMOS
2 Department of Biology [Washington]
3 GSFC Solar System Exploration Division
4 UF|Geological - Department of Geological Sciences [Gainesville]
5 Carnegie Earth and Planets Laboratory
6 LGPM - Laboratoire de Génie des Procédés et Matériaux
7 EAPS - Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge]
8 Department of Physics and Astronomy [Washington]
9 CRESST - Center for Research and Exploration in Space Science and Technology [GSFC]
10 Penn State Department of Geosciences
11 Jacobs Technology ESCG
12 EPS - Department of Earth and Planetary Science [UC Berkeley]
13 School of Chemistry and Biochemistry [Atlanta]
14 UNAM - Universidad Nacional Autónoma de México = National Autonomous University of Mexico
15 Astrogeology Science Center [Flagstaff]
16 GESTAR - Goddard Earth Sciences and Technology and Research

The Sample Analysis at Mars (SAM) suite instrument on board NASA’s Curiosity rover has characterized the inorganic and organic chemical composition of seven samples from the Glen Torridon clay-bearing unit. A variety of organic molecules were detected with SAM using pyrolysis (up to ~850°C) and wet chemistry experiments coupled with evolved gas analysis (EGA) and gas chromatography-mass spectrometry (GCMS). SAM EGA and GCMS analyses revealed a greater diversity and abundance of sulfur-bearing aliphatic and aromatic organic compounds in the sediments of this Gale crater unit than earlier in the mission. We also report the detection of nitrogen-containing, oxygen-containing, and chlorine- containing molecules, as well as polycyclic aromatic hydrocarbons found in Glen Torridon (GT), although the sources of some of these organics may be related to the presence of chemical reagents in the SAM instrument background. However, sulfur-bearing organics released at high temperature (>600°C) are likely derived from martian sources (e.g., igneous, hydrothermal, atmospheric, or biological) or exogenous sources and consistent with the presence of recalcitrant organic materials in the sample. The SAM measurements of the GT clay-bearing unit expand the inventory of organic matter present in Gale crater and is also consistent with the hypothesis that clay minerals played an important role in the preservation of ancient refractory organic matter on Mars. These findings deepen our understanding of the past habitability and biological potential of Gale crater.

Mots clés: Glen Torridon; Clays; Organic Molecules; Mars Science Laboratory; Sample Analysis at Mars; Pyrolysis-GCMS; Wet Chemistry

Domaines: Planète et Univers [physics]

Maeva Millan, Amy J. Williams, Amy C Mcadam, Jennifer L. Eigenbrode, Andrew Steele, et al.. Sedimentary Organics in Glen Torridon, Gale Crater, Mars: Results from the SAM Instrument Suite and Supporting Laboratory Analyses. Journal of Geophysical Research. Planets, 2022, 127 (11), pp.e2021JE007107. ⟨10.1029/2021je007107⟩. ⟨insu-03775640v3⟩