Chemistry and mineralogy of outcrops at Meridiani Planum

Clark, B. C.; Morris, R. V.; McLennan, Scott M.; Gellert, R.; Jolliff, Bradley L.; Knoll, Andrew H.; Squyres, S. W.; Lowenstein, Tim K.; Ming, D. W.; Tosca, Nicholas J.; Yen, A. S.; Christensen, P. R.; Gorevan, S.; Brückner, J.; Calvin, W. M.; Dreibus, G.; Farrand, W. H.; Klingelhoefer, G.; Waenke, H.; Zipfel, J.; Bell, James F.; Grotzinger, J. P.; McSween, H. Y.; Rieder, R.

doi:10.1016/j.epsl.2005.09.040

Cited by 364 publications

(355 citation statements)

References 58 publications

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“…Most other sulfate minerals hydrate and can change hydration state readily. Arcanite, K 2 SO 4 , is one of the few sulfates that is a stable non-hydrate and was also considered but potassium is not abundant on the martian surface and anhydrite is more representative of Ca-sulfates that Curiosity might encounter on Mars (e.g., Clark et al 2005). For the basaltic component, we used a specimen from Totavi, NM, USA, that has been analyzed many times as an internal standard for X-ray fluorescence analyses at Los Alamos National Laboratory (LANL).…”

Section: Preparation Methods and Selection Of Target Compositionsmentioning

confidence: 99%

Ceramic ChemCam Calibration Targets on Mars Science Laboratory

et al. 2012

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The ChemCam instrument on the Mars Science Laboratory rover Curiosity will use laser-induced breakdown spectroscopy (LIBS) to analyze major and minor element chemistry from sub-millimeter spot sizes, at ranges of ∼1.5-7 m. To interpret the emission spectra obtained, ten calibration standards will be carried on the rover deck. Graphite, Ti metal, and four glasses of igneous composition provide primary, homogeneous calibration targets for the laser. Four granular ceramic targets have been added to provide compositions closer to soils and sedimentary materials like those expected at the Gale Crater field site on Mars. Components used in making these ceramics include basalt, evaporite, and phyllosilicate materials that approximate the chemical compositions of detrital and authigenic constituents of clastic and evaporite sediments, including the elevated sulfate contents present in many Mars sediments and soils. Powdered components were sintered at low temperature (800°C) with a small amount (9 wt.%) of lithium tetraborate flux to produce ceramics that retain volatile sulfur yet are durable enough for the mission. The ceramic targets are more heterogeneous than the pure element and homogenous glass standards but they provide standards with compositions more similar to the sedimentary rocks that will be Curiosity's prime targets at Gale Crater.

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Section: Preparation Methods and Selection Of Target Compositionsmentioning

confidence: 99%

Ceramic ChemCam Calibration Targets on Mars Science Laboratory

et al. 2012

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“…These outcrops are composed dominantly of fineto medium-grained sandstones. Geochemical and mineralogic data show that the grains are composed of 50% fine-grained siliciclastic materials derived from the weathering of basaltic rock, 40% sulfate minerals, and 10% hematite Clark et al 2005). Exposed rocks are soft, as revealed through grinding using the rock abrasion tool (RAT); they have a resistance to abrasion similar to talc .…”

Section: Regional Settingmentioning

confidence: 99%

Sulfate-Rich Eolian and Wet Interdune Deposits, Erebus Crater, Meridiani Planum, Mars

Metz

Grotzinger

Rubin

et al. 2009

Journal of Sedimentary Research

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This study investigates three bedrock exposures at Erebus crater, an , 300 m diameter crater approximately 4 km south of Endurance crater on Mars. These outcrops, called Olympia, Payson, and Yavapai, provide additional evidence in support of the dune-interdune model proposed for the formation of the deposits at the Opportunity landing site in Meridiani Planum. There is evidence for greater involvement of liquid water in the Olympia outcrop exposures than was observed in Eagle or Endurance craters. The Olympia outcrop likely formed in a wet interdune and sand sheet environment. The facies observed within the Payson outcrop, which is likely stratigraphically above the Olympia outcrop, indicate that it was deposited in a damp-wet interdune, sand sheet, and eolian dune environment. The Yavapai outcrop, which likely stratigraphically overlies the Payson outcrop, indicates that it was deposited in primarily a sand sheet environment and also potentially in an eolian dune environment. These three outcrop exposures may indicate an overall drying-upward trend spanning the stratigraphic section from its base at the Olympia outcrop to its top at the Yavapai outcrop. This contrasts with the wetting-upward trend seen in Endurance and Eagle craters. Thus, the series of outcrops seen at Meridiani by Opportunity may constitute a full climatic cycle, evolving from dry to wet to dry conditions.

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“…Perhaps some of the inhibition of microbial growth and replication at low pressure might be relaxed in bacterial and archaeal species with ClC Cl Ϫ channels when cells are in the presence of Cl Ϫ salts. Chloride salts have been confirmed for Mars regolith in several locations, including Meridiani Planum (Opportunity rover), Gusev Crater (Spirit rover), and the northern polar plains (Phoenix lander) (8,21,35). Current results suggest that bacterial species with ClC Cl Ϫ channels may be more capable of survival, and possibly growth, on Mars.…”

Section: Discussionmentioning

confidence: 72%

“…Bacteria were grown in all possible combinations of three salts (MgSO 4 , MgCl 2 , and NaCl), four salt concentrations (0, 5, 10, or 20%), and four temperatures (5, 10, 20, or 30°C) to study the interactive effects of salt and temperature on bacterial survival and growth. Salts were selected based on published literature identifying MgSO 4 , MgCl 2 , and NaCl on Mars (8,55). Cultures were prepared in 5 ml sterile mLB broth containing each of the salts at each of the concentrations and incubated at each temperature.…”

Section: Methodsmentioning

confidence: 99%

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Effects of Simulated Mars Conditions on the Survival and Growth of Escherichia coli and Serratia liquefaciens

Berry

Jenkins

Schuerger

2010

Appl Environ Microbiol

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Escherichia coli and Serratia liquefaciens, two bacterial spacecraft contaminants known to replicate under low atmospheric pressures of 2.5 kPa, were tested for growth and survival under simulated Mars conditions. Environmental stresses of high salinity, low temperature, and low pressure were screened alone and in combination for effects on bacterial survival and replication, and then cells were tested in Mars analog soils under simulated Mars conditions. Survival and replication of E. coli and S. liquefaciens cells in liquid medium were evaluated for 7 days under low temperatures (5, 10, 20, or 30°C) with increasing concentrations (0, 5, 10, or 20%) of three salts (MgCl 2 , MgSO 4 , NaCl) reported to be present on the surface of Mars. Moderate to high growth rates were observed for E. coli and S. liquefaciens at 30 or 20°C and in solutions with 0 or 5% salts. In contrast, cell densities of both species generally did not increase above initial inoculum levels under the highest salt concentrations (10 and 20%) and the four temperatures tested, with the exception that moderately higher cell densities were observed for both species at 10% MgSO 4 maintained at 20 or 30°C. Growth rates of E. coli and S. liquefaciens in low salt concentrations were robust under all pressures (2.5, 10, or 101.3 kPa), exhibiting a general increase of up to 2.5 orders of magnitude above the initial inoculum levels of the assays. Vegetative E. coli cells were maintained in a Mars analog soil for 7 days under simulated Mars conditions that included temperatures between 20 and ؊50°C for a day/night diurnal period, UVC irradiation (200 to 280 nm) at 3.6 W m ؊2 for daytime operations (8 h), pressures held at a constant 0.71 kPa, and a gas composition that included the top five gases found in the martian atmosphere. Cell densities of E. coli failed to increase under simulated Mars conditions, and survival was reduced 1 to 2 orders of magnitude by the interactive effects of desiccation, UV irradiation, high salinity, and low pressure (in decreasing order of importance). Results suggest that E. coli may be able to survive, but not grow, in surficial soils on Mars.The search for extant life on Mars remains a stated goal of NASA's Mars Exploration Program and Astrobiology Institutes (13,17). Intrinsic within such a life detection strategy is a requirement to understand how terrestrial life might survive, replicate, and proliferate on Mars. To mitigate the risks of the forward contamination of Mars, the bioloads on spacecrafts targeted for landing must be reduced to low density and diversity (4, 7). Planetary protection guidelines are designed to prevent both the forward contamination of the martian surface and to ensure the scientific integrity of any deployed life detection experiments. To date, 12 spacecraft have landed or crashed onto the Mars surface as a result of U.S., Russian, and European space program missions, but it is currently unknown if terrestrial microorganisms typically found on spacecraft surfaces can grow and replicate under con...

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Chemistry and mineralogy of outcrops at Meridiani Planum

Cited by 364 publications

References 58 publications

Ceramic ChemCam Calibration Targets on Mars Science Laboratory

Ceramic ChemCam Calibration Targets on Mars Science Laboratory

Sulfate-Rich Eolian and Wet Interdune Deposits, Erebus Crater, Meridiani Planum, Mars

Effects of Simulated Mars Conditions on the Survival and Growth of Escherichia coli and Serratia liquefaciens

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