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Evolved gas analyses of sedimentary rocks and eolian sediment in Gale Crater, Mars: Results of the Curiosity rover's sample analysis at Mars instrument from Yellowknife Bay to the Namib Dune
Author(s) -
Sutter B.,
McAdam A. C.,
Mahaffy P. R.,
Ming D. W.,
Edgett K. S.,
Rampe E. B.,
Eigenbrode J. L.,
Franz H. B.,
Freissinet C.,
Grotzinger J. P.,
Steele A.,
House C. H.,
Archer P. D.,
Malespin C. A.,
NavarroGonzález R.,
Stern J. C.,
Bell J. F.,
Calef F. J.,
Gellert R.,
Glavin D. P.,
Thompson L. M.,
Yen A. S.
Publication year - 2017
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2016je005225
Subject(s) - impact crater , geology , mars exploration program , sedimentary rock , carbonate , geochemistry , mineralogy , aeolian processes , sulfate , magnesite , pyrite , astrobiology , chemistry , geomorphology , physics , organic chemistry , magnesium
Abstract The sample analysis at Mars instrument evolved gas analyzer (SAM‐EGA) has detected evolved water, H 2 , SO 2 , H 2 S, NO, CO 2 , CO, O 2 , and HCl from two eolian sediments and nine sedimentary rocks from Gale Crater, Mars. These evolved gas detections indicate nitrates, organics, oxychlorine phase, and sulfates are widespread with phyllosilicates and carbonates occurring in select Gale Crater materials. Coevolved CO 2 (160 ± 248–2373 ± 820 μgC (CO2) /g) and CO (11 ± 3–320 ± 130 μgC (CO) /g) suggest that organic C is present in Gale Crater materials. Five samples evolved CO 2 at temperatures consistent with carbonate (0.32 ± 0.05–0.70 ± 0.1 wt % CO 3 ). Evolved NO amounts to 0.002 ± 0.007–0.06 ± 0.03 wt % NO 3 . Evolution of O 2 suggests that oxychlorine phases (chlorate/perchlorate) (0.05 ± 0.025–1.05 ± 0.44 wt % ClO 4 ) are present, while SO 2 evolution indicates the presence of crystalline and/or poorly crystalline Fe and Mg sulfate and possibly sulfide. Evolved H 2 O (0.9 ± 0.3–2.5 ± 1.6 wt % H 2 O) is consistent with the presence of adsorbed water, hydrated salts, interlayer/structural water from phyllosilicates, and possible inclusion water in mineral/amorphous phases. Evolved H 2 and H 2 S suggest that reduced phases occur despite the presence of oxidized phases (nitrate, oxychlorine, sulfate, and carbonate). SAM results coupled with CheMin mineralogical and Alpha‐Particle X‐ray Spectrometer elemental analyses indicate that Gale Crater sedimentary rocks have experienced a complex authigenetic/diagenetic history involving fluids with varying pH, redox, and salt composition. The inferred geochemical conditions were favorable for microbial habitability and if life ever existed, there was likely sufficient organic C to support a small microbial population.