ORALS
SESSION:
GeochemistryTuePM1-R8
| Navrotsky International Symposium (2nd Intl. Symp. on Geochemistry for Sustainable Development) |
| Tue. 28 Nov. 2023 / Room: Coral Reef | |
| Session Chairs: Megan Householder; Zi-Kui Liu; Session Monitor: TBA |
15:20: [GeochemistryTuePM108] OL
THERMODYNAMIC INSIGHT INTO COMPLEX OXIDES OF MARTIAN RELEVANCE Christophe Drouet1 ;
Alexandra Navrotsky2 ;
1CIRIMAT Institute, Toulouse, France;
2Arizona State University, Phoenix, United States;
Paper Id: 458
[Abstract] A series of complex oxides have, along the years, raised interest in the field of Martian mineralogy. This includes compounds of the Jarosite, Apatite and Jahnsite large groups of minerals. Whereas some of them, typically F- and Cl-apatites have been identified on the red planet, the presence of some other phases like Jarosites and more recently Jahnsites have been suspected to occur on Mars without actual proofs of their presence. Whether for confirming or invalidating the possible presence of such oxide phases on the surface of Mars, or for better assessing their eventual evolution in the Martian atmosphere and surface conditions, it is primordial to have access to thermodynamic data – as much reliable as possible – yet sometimes scarcely available. Thus, in this long run work along the years, we have launched synthesis procedures with the view to prepare relevant compositions of these three families of minerals ore relevance to Mars mineralogy, and explored their thermodynamics through oxide-melt solution calorimetry when possible, and via the ThermAP (Applied Predictive Thermodynamics) simplified predictive approach. In this presentation, the main milestones and findings of this research will be reminded, and the main thermodynamic trends will be highlighted with regards to Jarosites, Apatites and Jahnsites.
References:
[1] A. Navrotsky, F.L. Forray, C. Drouet, Jarosite stability on Mars, Icarus 176 (2005) 250-253.
[2] C. Drouet, A Comprehensive Guide to Experimental and Predicted Thermodynamic Properties of Phosphate Apatite Minerals in view of Applicative Purposes, The Journal of Chemical Thermodynamics, 81 (2015) 143-159 (= initiation of the ThermAP model).
[3] C. Drouet, Applied predictive thermodynamics (ThermAP). Part 2. Apatites containing Ni2+, Co2+, Mn2+, or Fe2+ ions, The Journal of Chemical Thermodynamics, 136 (2019) 182-189 (= extension of the ThermAP model).
[4] Fau et al., Time-resolved Raman and luminescence spectroscopy of synthetic REE-doped hydroxylapatites and natural apatites, The American Mineralogist, 107(7) (2022) 1341-1352.
[5] C. Drouet, M. Loche, S. Fabre, P.Y. Meslin, On the occurrence of Jahnsite/Whiteite phases on Mars: a thermodynamic study, The American Mineralogist, 107(9) (2022) 1807-1817.
