Sulfur‐bearing phases detected by evolved gas analysis of the Rocknest aeolian deposit, Gale Crater, Mars. Issue 2 (15th February 2014)

• Record Type: Journal Article
• Authors: McAdam, Amy C.; Franz, Heather B.; Sutter, Brad; Archer, Paul D.; Freissinet, Caroline; Eigenbrode, Jennifer L.; Ming, Douglas W.; Atreya, Sushil K.; Bish, David L.; Blake, David F.; Bower, Hannah E.; Brunner, Anna; Buch, Arnaud; Glavin, Daniel P.; Grotzinger, John P.; Mahaffy, Paul R.; McLennan, Scott M.; Morris, Richard V.; Navarro‐González, Rafael; Rampe, Elizabeth B.; Squyres, Steven W.; Steele, Andrew; Stern, Jennifer C.; Sumner, Dawn Y.; Wray, James J.
• Is Part Of: Journal of geophysical research. Volume 119:Issue 2(2014:Feb.)
• Page Start: 373
• Page End: 393
• Publication Date: 2014-02-15
• Subjects: Planets -- Periodicals; Geophysics -- Periodicals; 559.9
• DOI: 10.1002/2013JE004518
• Languages: English
• ISSNs: 2169-9097

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>The Sample Analysis at Mars (SAM) instrument suite detected SO<sub>2</sub>, H<sub>2</sub>S, OCS, and CS<sub>2</sub> from ~450 to 800°C during evolved gas analysis (EGA) of materials from the Rocknest aeolian deposit in Gale Crater, Mars. This was the first detection of evolved sulfur species from a Martian surface sample during in situ EGA. SO<sub>2</sub> (~3–22 µmol) is consistent with the thermal decomposition of Fe sulfates or Ca sulfites, or evolution/desorption from sulfur‐bearing amorphous phases. Reactions between reduced sulfur phases such as sulfides and evolved O<sub>2</sub> or H<sub>2</sub>O in the SAM oven are another candidate SO<sub>2</sub> source. H<sub>2</sub>S (~41–109 nmol) is consistent with interactions of H<sub>2</sub>O, H<sub>2</sub> and/or HCl with reduced sulfur phases and/or SO<sub>2</sub> in the SAM oven. OCS (~1–5 nmol) and CS<sub>2</sub> (~0.2–1 nmol) are likely derived from reactions between carbon‐bearing compounds and reduced sulfur. Sulfates and sulfites indicate some aqueous interactions, although not necessarily at the Rocknest site; Fe sulfates imply interaction with acid solutions whereas Ca sulfites can form from acidic to near‐neutral solutions. Sulfides in the Rocknest materials suggest input from materials originally deposited in a reducing environment or from detrital sulfides from an igneous source. The presence of sulfides also suggests that the materials have not been extensively altered by oxidative aqueous weathering. The possibility of both reduced and oxidized sulfur compounds in the deposit indicates a nonequilibrium assemblage. Understanding the sulfur mineralogy in Rocknest materials, which exhibit chemical similarities to basaltic fines analyzed elsewhere on Mars, can provide insight in to the origin and alteration history of Martian surface materials.</p> </abstract>