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Title: Redox stratification of an ancient lake in Gale crater, Mars

Abstract

In 2012, NASA’s Curiosity rover landed on Mars to assess its potential as a habitat for past life and investigate the paleoclimate record preserved by sedimentary rocks inside the ~150-kilometer-diameter Gale impact crater. Geological reconstructions from Curiosity rover data have revealed an ancient, habitable lake environment fed by rivers draining into the crater. We synthesize geochemical and mineralogical data from lake-bed mudstones collected during the first 1300 martian solar days of rover operations in Gale. We present evidence for lake redox stratification, established by depth-dependent variations in atmospheric oxidant and dissolved-solute concentrations. Paleoclimate proxy data indicate that a transition from colder to warmer climate conditions is preserved in the stratigraphy. Lastly, a late phase of geochemical modification by saline fluids is recognized.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [1]; ORCiD logo [3]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [6]; ORCiD logo [7]; ORCiD logo [8]; ORCiD logo [9]; ORCiD logo [10];  [11]; ORCiD logo [12]; ORCiD logo [13]; ORCiD logo [13];  [14]; ORCiD logo [15] more »;  [2]; ORCiD logo [16]; ORCiD logo [17] « less
  1. Stony Brook Univ., Stony Brook, NY (United States)
  2. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  3. Brown Univ., Providence, RI (United States)
  4. NASA Ames Research Center (ARC), Moffett Field, CA (United States)
  5. Univ. Paul Sabatier, Toulouse (France)
  6. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  7. Consejo Superior de Investigaciones Cientificas - Instituto Nacional de Tecnica Aeroespacial (CSIC-INTA), Madrid (Spain); Cornell Univ., Ithaca, NY (United States)
  8. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Copenhagen, Copenhagen (Denmark)
  9. Univ. of Guelph, Guelph, ON (Canada)
  10. Smithsonian Institution, Washington, D.C. (United States)
  11. Imperial College, London (United Kingdom)
  12. U.S. Geological Survey, Flagstaff, AZ (United States)
  13. NASA Johnson Space Center, Houston, TX (United States)
  14. Brock Univ., St. Catharines, ON (Canada)
  15. Stony Brook Univ., Stony Brook, NY (United States); California Inst. of Technology (CalTech), Pasadena, CA (United States)
  16. Univ. of California, Davis, CA (United States)
  17. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
National Aeronautic and Space Administration (NASA); USDOE
OSTI Identifier:
1418769
Report Number(s):
LA-UR-17-27689
Journal ID: ISSN 0036-8075
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Science
Additional Journal Information:
Journal Volume: 356; Journal Issue: 6341; Journal ID: ISSN 0036-8075
Publisher:
AAAS
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Planetary Sciences

Citation Formats

Hurowitz, Joel A., Grotzinger, John P., Fischer, Woodward W., McLennan, Scott M., Milliken, Ralph E., Stein, Nathan, Vasavada, Ashwin R., Blake, David F., Dehouck, Erwin, Eigenbrode, Jen L., Fairen, Alberto G., Frydenvang, Jens, Gellert, Ralf, Grant, John A., Gupta, Sanjeev, Herkenhoff, Kenneth E., Ming, Doug W., Rampe, Elizabeth B., Schmidt, Mariek E., Siebach, Kirsten L., Stack-Morgan, Katherine, Sumner, Dawn Y., and Wiens, Roger Craig. Redox stratification of an ancient lake in Gale crater, Mars. United States: N. p., 2017. Web. doi:10.1126/science.aah6849.
Hurowitz, Joel A., Grotzinger, John P., Fischer, Woodward W., McLennan, Scott M., Milliken, Ralph E., Stein, Nathan, Vasavada, Ashwin R., Blake, David F., Dehouck, Erwin, Eigenbrode, Jen L., Fairen, Alberto G., Frydenvang, Jens, Gellert, Ralf, Grant, John A., Gupta, Sanjeev, Herkenhoff, Kenneth E., Ming, Doug W., Rampe, Elizabeth B., Schmidt, Mariek E., Siebach, Kirsten L., Stack-Morgan, Katherine, Sumner, Dawn Y., & Wiens, Roger Craig. Redox stratification of an ancient lake in Gale crater, Mars. United States. doi:10.1126/science.aah6849.
Hurowitz, Joel A., Grotzinger, John P., Fischer, Woodward W., McLennan, Scott M., Milliken, Ralph E., Stein, Nathan, Vasavada, Ashwin R., Blake, David F., Dehouck, Erwin, Eigenbrode, Jen L., Fairen, Alberto G., Frydenvang, Jens, Gellert, Ralf, Grant, John A., Gupta, Sanjeev, Herkenhoff, Kenneth E., Ming, Doug W., Rampe, Elizabeth B., Schmidt, Mariek E., Siebach, Kirsten L., Stack-Morgan, Katherine, Sumner, Dawn Y., and Wiens, Roger Craig. Fri . "Redox stratification of an ancient lake in Gale crater, Mars". United States. doi:10.1126/science.aah6849.
@article{osti_1418769,
title = {Redox stratification of an ancient lake in Gale crater, Mars},
author = {Hurowitz, Joel A. and Grotzinger, John P. and Fischer, Woodward W. and McLennan, Scott M. and Milliken, Ralph E. and Stein, Nathan and Vasavada, Ashwin R. and Blake, David F. and Dehouck, Erwin and Eigenbrode, Jen L. and Fairen, Alberto G. and Frydenvang, Jens and Gellert, Ralf and Grant, John A. and Gupta, Sanjeev and Herkenhoff, Kenneth E. and Ming, Doug W. and Rampe, Elizabeth B. and Schmidt, Mariek E. and Siebach, Kirsten L. and Stack-Morgan, Katherine and Sumner, Dawn Y. and Wiens, Roger Craig},
abstractNote = {In 2012, NASA’s Curiosity rover landed on Mars to assess its potential as a habitat for past life and investigate the paleoclimate record preserved by sedimentary rocks inside the ~150-kilometer-diameter Gale impact crater. Geological reconstructions from Curiosity rover data have revealed an ancient, habitable lake environment fed by rivers draining into the crater. We synthesize geochemical and mineralogical data from lake-bed mudstones collected during the first 1300 martian solar days of rover operations in Gale. We present evidence for lake redox stratification, established by depth-dependent variations in atmospheric oxidant and dissolved-solute concentrations. Paleoclimate proxy data indicate that a transition from colder to warmer climate conditions is preserved in the stratigraphy. Lastly, a late phase of geochemical modification by saline fluids is recognized.},
doi = {10.1126/science.aah6849},
journal = {Science},
number = 6341,
volume = 356,
place = {United States},
year = {Fri Jun 02 00:00:00 EDT 2017},
month = {Fri Jun 02 00:00:00 EDT 2017}
}

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Cited by: 9works
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  • We report that the Curiosity rover observed high Mn abundances (>25 wt % MnO) in fracture-filling materials that crosscut sandstones in the Kimberley region of Gale crater, Mars. The correlation between Mn and trace metal abundances plus the lack of correlation between Mn and elements such as S, Cl, and C, reveals that these deposits are Mn oxides rather than evaporites or other salts. On Earth, environments that concentrate Mn and deposit Mn minerals require water and highly oxidizing conditions; hence, these findings suggest that similar processes occurred on Mars. In conclusion, based on the strong association between Mn-oxide depositionmore » and evolving atmospheric dioxygen levels on Earth, the presence of these Mn phases on Mars suggests that there was more abundant molecular oxygen within the atmosphere and some groundwaters of ancient Mars than in the present day.« less
  • The Mars Science Laboratory rover Curiosity encountered potassium-rich clastic sedimentary rocks at two sites in Gale Crater, the waypoints Cooperstown and Kimberley. These rocks include several distinct meters thick sedimentary outcrops ranging from fine sandstone to conglomerate, interpreted to record an ancient fluvial or fluvio-deltaic depositional system. Furthermore, from ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) chemical analyses, this suite of sedimentary rocks has an overall mean K 2O abundance that is more than 5 times higher than that of the average Martian crust. The combined analysis of ChemCam data with stratigraphic and geographic locations then reveals that the mean K 2Omore » abundance increases upward through the stratigraphic section. Chemical analyses across each unit can be represented as mixtures of several distinct chemical components, i.e., mineral phases, including K-bearing minerals, mafic silicates, Fe-oxides, and Fe-hydroxide/oxyhydroxides. Possible K-bearing minerals include alkali feldspar (including anorthoclase and sanidine) and K-bearing phyllosilicate such as illite. Mixtures of different source rocks, including a potassium-rich rock located on the rim and walls of Gale Crater, are the likely origin of observed chemical variations within each unit. Physical sorting may have also played a role in the enrichment in K in the Kimberley formation. The occurrence of these potassic sedimentary rocks provides additional evidence for the chemical diversity of the crust exposed at Gale Crater.« less
  • At Gale crater, Mars, ChemCam acquired its first laser-induced breakdown spectroscopy (LIBS) target on Sol 13 of the landed portion of the mission (a Sol is a Mars day).
  • The Mars Science Laboratory rover Curiosity found host rocks of basaltic composition and alteration assemblages containing clay minerals at Yellowknife Bay, Gale Crater. On the basis of the observed host rock and alteration minerals, we present results of equilibrium thermochemical modeling of the Sheepbed mudstones of Yellowknife Bay in order to constrain the formation conditions of its secondary mineral assemblage. Building on conclusions from sedimentary observations by the Mars Science Laboratory team, we assume diagenetic, in situ alteration. The modeling shows that the mineral assemblage formed by the reaction of a CO₂-poor and oxidizing, dilute aqueous solution (Gale Portage Water)more » in an open system with the Fe-rich basaltic-composition sedimentary rocks at 10–50°C and water/rock ratio (mass of rock reacted with the starting fluid) of 100–1000, pH of ~7.5–12. Model alteration assemblages predominantly contain phyllosilicates (Fe-smectite, chlorite), the bulk composition of a mixture of which is close to that of saponite inferred from Chemistry and Mineralogy data and to that of saponite observed in the nakhlite Martian meteorites and terrestrial analogues. To match the observed clay mineral chemistry, inhomogeneous dissolution dominated by the amorphous phase and olivine is required. We therefore deduce a dissolving composition of approximately 70% amorphous material, with 20% olivine, and 10% whole rock component.« less
  • Zinc-enriched targets have been detected at the Kimberley formation, Gale crater, Mars, using the Chemistry Camera (ChemCam) instrument. The Zn content is analyzed with a univariate calibration based on the 481.2 nm emission line. The limit of quantification for ZnO is 3 wt % (at 95% confidence level) and 1 wt % (at 68% confidence level). The limit of detection is shown to be around 0.5 wt %. As of sol 950, 12 targets on Mars present high ZnO content ranging from 1.0 wt % to 8.4 wt % (Yarrada, sol 628). Those Zn-enriched targets are almost entirely located atmore » the Dillinger member of the Kimberley formation, where high Mn and alkali contents were also detected, probably in different phases. Zn enrichment does not depend on the textures of the rocks (coarse-grained sandstones, pebbly conglomerates, and resistant fins). The lack of sulfur enhancement suggests that Zn is not present in the sphalerite phase. Zn appears somewhat correlated with Na 2O and the ChemCam hydration index, suggesting that it could be in an amorphous clay phase (such as sauconite). On Earth, such an enrichment would be consistent with a supergene alteration of a sphalerite gossan cap in a primary siliciclastic bedrock or a possible hypogene nonsulfide zinc deposition where Zn, Fe, Mn would have been transported in a reduced sulfur-poor fluid and precipitated rapidly in the form of oxides.« less