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NOTE ADDED BY JPL WEBMASTER: This content has not been approved or adopted by, NASA, JPL, or the California Institute of Technology. This
document is being made available for information purposes only, and any views and opinions expressed herein do not necessarily state or reflect those
of NASA, JPL, or the California Institute of Technology.
H. Clenet, C. Quantin, M. Andreani and P. Allemand
29/02/2012, Washington
CARBONATE-BEARING CRUSTAL EXPOSURE IN AN IMPACT CRATER ASSOCIATED WITH AN
OUTFLOW CHANNEL CONTEXT
[email protected]@univ-lyon1.fr
Regional context
Map from Edwards et al., 2008, JGR
Proposed landing site
Olivine layer in Eos Chasma
Mineralogy in thecentral peak
R : LCPINDEX [0.05-0.14]G: HPCINDEX [0.05-0.23]B: OLINDEX [0.005-0.05]
From Ehlmann et al., 2008
« Direct » carbonation reactionsForsterite → Magnésite
Fayalite→ Sidérite
Enstatite → Magnésite Ferrosilite → Sidérite
Diopside → Dolomite
High PCO2
3𝐹𝑒2𝑆𝑖𝑂4+𝑆𝑖𝑂2+2𝐻 2𝑂→2𝑀𝑔3𝑆𝑖2𝑂5(𝑂𝐻 )4
Serpentinization of olivine (fayalite + aqueous silica = serpentine)
2𝑀𝑔3𝑆𝑖2𝑂5(𝑂𝐻 )4+3𝐶𝑂2→𝑀𝑔3 𝑆𝑖4𝑂10(𝑂𝐻 )2+3𝑀𝑔𝐶𝑂3+𝐻 2𝑂Carbonation of serpentine (serpentine + CO2 = talc + magnésite)
Serpentine and carbonation reactions
Low PCO2
Circulation of fluids enriched in CO2
High PCO2
then
© IPGP (CNRS, Univ Paris Diderot)/Università di Modena e Reggio EmiliaMenez et al., Nature Geoscience 2012
Blue=hydrogarnet (Ca3Al2(SiO4)3-x(OH)4x)Green=serpentinized pyroxeneRed=Ferric oxydeYellow=organic molecules
Serpentinization of olivine (forsterite + H2O = serpentine + brucite + magnetite)
2𝑀𝑔3𝑆𝑖2𝑂5(𝑂𝐻 )4+3𝐶𝑂2→𝑀𝑔3 𝑆𝑖4𝑂10(𝑂𝐻 )2+3𝑀𝑔𝐶𝑂3+𝐻 2𝑂Carbonation of serpentine (serpentine + CO2 = talc + magnésite)
Serpentine and carbonation reactions
𝑀𝑔1,8 𝐹𝑒0,2𝑆𝑖𝑂4+1,37𝐻2𝑂→0,5𝑀𝑔3𝑆𝑖2𝑂5(𝑂𝐻 )4+3𝑀𝑔(𝑂𝐻 )2+0,067𝐹𝑒3𝑂4 +0,067𝐻 2
Low PCO2
High PCO2
then
Habitability?
Circulation of fluids enriched in CO2
Hydrothermal system Hesperian aqueous activity
Emplacement of the mafic unit
Post-impact process
?
Paleolake induced deposits
High T° Low T°
Landing contraints
Elevation
Slope
Conclusion
-Primitive martian crust
-Putative hydrothermal system and its exobiological niches
-Outflow channel context