A Review of Sample Analysis at Mars-Evolved Gas Analysis Laboratory Analog Work Supporting the Presence of Perchlorates and Chlorates in Gale Crater, Mars

The Sample Analysis at Mars (SAM) instrument on the Curiosity rover has detected evidence of oxychlorine compounds (i.e., perchlorates and chlorates) in Gale crater, which has implications for past habitability, diagenesis, aqueous processes, interpretation of in situ organic analyses, understanding the martian chlorine cycle, and hazards and resources for future human exploration. Pure oxychlorines and mixtures of oxychlorines with Mars-analog phases have been analyzed for their oxygen (O2) and hydrogen chloride (HCl) releases on SAM laboratory analog instruments in order to constrain which phases are present in Gale crater. These studies demonstrated that oxychlorines evolve O2 releases with peaks between ~200 and 600 °C, although the thermal decomposition temperatures and the amount of evolved O2 decrease when iron phases are present in the sample. Mg and Fe oxychlorines decompose into oxides and release HCl between ~200 and 542 °C. Ca, Na, and K oxychlorines thermally decompose into chlorides and do not evolve HCl by themselves. However, the chlorides (original or from oxychlorine decomposition) can react with water-evolving phases (e.g., phyllosilicates) in the sample and evolve HCl within the temperature range of SAM (<~870 °C). These laboratory analog studies support that the SAM detection of oxychlorine phases is consistent with the presence of Mg, Ca, Na, and K perchlorate and/or chlorate along with possible contributions from adsorbed oxychlorines in Gale crater samples.

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Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars

Science ◽

10.1126/science.aas9185 ◽

2018 ◽

Vol 360 (6393) ◽

pp. 1096-1101 ◽

Cited By ~ 133

Author(s):

Jennifer L. Eigenbrode ◽

Roger E. Summons ◽

Andrew Steele ◽

Caroline Freissinet ◽

Maëva Millan ◽

...

Keyword(s):

Organic Matter ◽

Evolved Gas Analysis ◽

Gas Analysis ◽

Gas Chromatography Mass Spectrometry ◽

Pyrolysis Products ◽

Evolved Gas ◽

Gale Crater ◽

In Situ Detection ◽

Curiosity Rover

Establishing the presence and state of organic matter, including its possible biosignatures, in martian materials has been an elusive quest, despite limited reports of the existence of organic matter on Mars. We report the in situ detection of organic matter preserved in lacustrine mudstones at the base of the ~3.5-billion-year-old Murray formation at Pahrump Hills, Gale crater, by the Sample Analysis at Mars instrument suite onboard the Curiosity rover. Diverse pyrolysis products, including thiophenic, aromatic, and aliphatic compounds released at high temperatures (500° to 820°C), were directly detected by evolved gas analysis. Thiophenes were also observed by gas chromatography–mass spectrometry. Their presence suggests that sulfurization aided organic matter preservation. At least 50 nanomoles of organic carbon persists, probably as macromolecules containing 5% carbon as organic sulfur molecules.

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Application of Ion Attachment Mass Spectrometry to Evolved Gas Analysis for in Situ Monitoring of Porous Ceramic Processing

Analytical Chemistry ◽

10.1021/ac0518248 ◽

2006 ◽

Vol 78 (7) ◽

pp. 2366-2369 ◽

Cited By ~ 10

Author(s):

Takahisa Tsugoshi ◽

Takaaki Nagaoka ◽

Megumi Nakamura ◽

Yoshiro Shiokawa ◽

Koji Watari

Keyword(s):

Mass Spectrometry ◽

Evolved Gas Analysis ◽

Porous Ceramic ◽

Gas Analysis ◽

In Situ Monitoring ◽

Ceramic Processing ◽

Evolved Gas ◽

Ion Attachment

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Detection of organic carbon in Mars-analog paleosols with thermal and evolved gas analysis

10.31223/x50g88 ◽

2021 ◽

Author(s):

Adrian Broz ◽

Joanna Clark ◽

Brad Sutter ◽

Doug Ming ◽

Briony Horgan ◽

...

Keyword(s):

Organic Carbon ◽

Evolved Gas Analysis ◽

Gas Analysis ◽

14C Dating ◽

Mars Rover ◽

Evolved Gas ◽

Near Surface ◽

Carbon Decomposition ◽

Preservation Potential ◽

Mars Analog

Decades of space exploration have shown that surface environments on Mars were habitable billions of years ago. Ancient, buried surface environments, or paleosols, may have been preserved in the geological record on Mars, and are considered high-priority targets for biosignature investigation. Studies of paleosols on Earth that are compositionally similar to putative martian paleosols can provide a reference frame for constraining their organic preservation potential on Mars. However, terrestrial paleosols typically preserve only trace amounts of organic carbon, and it remains unclear whether the organic component of paleosols can be detected with Mars rover-like instruments. Furthermore, the study of terrestrial paleosols is complicated by diagenetic additions of organic carbon, which can confound interpretations of their organic preservation potential. The objectives of this study were a) to determine whether organic carbon in ~30-million-year-old Mars-analog paleosols can be detected with thermal and evolved gas analysis, and b) constrain the age of organic carbon using radiocarbon (14C) dating to identify late diagenetic additions of carbon. Al/ Fe smectite-rich paleosols from the Early Oligocene (33 Ma) John Day Formation in eastern Oregon were examined with a thermal and evolved gas analyzer configured to operate similarly to the Sample Analysis at Mars Evolved Gas Analysis (SAM-EGA) instrument onboard the Mars Science Laboratory Curiosity rover. All samples evolved CO2 with peaks at ~400 °C and ~700° C from the thermal decomposition of refractory organic carbon and small amounts of calcium carbonate, respectively. Evolutions of organic fragments co-occurred with evolutions of CO2 from organic carbon decomposition. Total organic carbon (TOC) ranged from 0.002 - 0.032 ± 0.006 wt. %. Like modern soils, the near-surface horizons of all paleosols had significantly higher TOC relative to subsurface layers. Radiocarbon dating of four samples revealed an organic carbon age ranging between ~6,200 – 14,500 years before present, suggesting there had been inputs of exogenous organic carbon during diagenesis. By contrast, refractory carbon detected with EGA and enrichment of TOC in near-surface horizons of all three buried profiles were consistent with the preservation of trace amounts of endogenous organic carbon. This work demonstrates that near-surface horizons of putative martian paleosols should be considered high priority locations for in-situ biosignature investigation and reveals challenges for examining organic matter preservation in terrestrial paleosols.

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