Tronche, E. J. and van Kan Parker, M. and de Vries, J. and Wang, Y. and Sanehira, T. and Li, J. and Chen, B. and Gao, L. and Klemme, S. and McCammon, C. A. and van Westrenen, W. (2010) The thermal equation of state of FeTiO_3 ilmenite based on in situ X-ray diffraction at high pressures and temperatures. American Mineralogist, 95 (11-12). pp. 1708-1716. ISSN 0003-004X http://resolver.caltech.edu/CaltechAUTHORS:20101207-100818824
- Published Version
See Usage Policy.
Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20101207-100818824
We present in situ measurements of the unit-cell volume of a natural terrestrial ilmenite (Jagersfontein mine, South Africa) and a synthetic reduced ilmenite (FeTiO_3) at simultaneous high pressure and high temperature up to 16 GPa and 1273 K. Unit-cell volumes were determined using energy-dispersive synchrotron X-ray diffraction in a multi-anvil press. Mössbauer analyses show that the synthetic sample contained insignificant amounts of Fe^(3+) both before and after the experiment. Results were fit to Birch-Murnaghan thermal equations of state, which reproduce the experimental data to within 0.5 and 0.7 GPa for the synthetic and natural samples, respectively. At ambient conditions, the unit-cell volume of the natural sample [V_0 = 314.75 ± 0.23 (1 ) Å^3] is significantly smaller than that of the synthetic sample [V_0 = 319.12 ± 0.26 Å^3]. The difference can be attributed to the presence of impurities and Fe^(3+) in the natural sample. The 1 bar isothermal bulk moduli K_(T0) for the reduced ilmenite is slightly larger than for the natural ilmenite (181 ± 7 and 165 ± 6 GPa, respectively), with pressure derivatives K_0' = 3 ± 1. Our results, combined with literature data, suggest that the unit-cell volume of reduced ilmenite is significantly larger than that of oxidized ilmenite, whereas their thermoelastic parameters are similar. Our data provide more appropriate input parameters for thermo-chemical models of lunar interior evolution, in which reduced ilmenite plays a critical role.
|Additional Information:||© 2010 Mineralogical Society of America. Manuscript received September 29, 2009; Manuscript accepted July 3, 2010; Manuscript handled by Artem Oganov. We thank De Beers Group Services for supplying the natural ilmenite sample, Wim Lustenhouwer for support during electron microprobe analysis, and Xinyang Chen and Zeyu Li for support during synchrotron experiments. We thank Jelle van Sijl for creating a GSAS conversion program for this work. Comments by three anonymous reviewers significantly improved the quality of this manuscript. Portions of this work were performed at GeoSoilEnviroCARS (Sector 13), Advanced Photon Source (APS), Argonne National Laboratory. GeoSoilEnviroCARS is supported by the National Science Foundation-Earth Sciences (EAR-0217473), Department of Energy-Geosciences (DE-FG02-94ER14466), and the State of Illinois. Use of the APS was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. W-31-109-ENG-38, partially by COMPRES, the COnsortium for Materials Properties Research in Earth Sciences under NSF Cooperative Agreement EAR06-49658. J.L. acknowledges support by NASA grant NNX09AB946 and NSF grants EAR069639 and EAR0738973. B.C. acknowledges support by the Texaco Postdoctoral Fellowship from the Division of Geological and Planetary Sciences, California Institute of Technology. This work was funded by a European Science Foundation EURYI award to W.v.W.|
|Subject Keywords:||Ilmenite; equation of state; X-ray diffraction; lunar magma ocean|
|Official Citation:||Tronche, E. J., M. van Kan Parker, et al. (2010). "The thermal equation of state of FeTiO3 ilmenite based on in situ X-ray diffraction at high pressures and temperatures." American Mineralogist 95(11-12): 1708-1716.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||10 Dec 2010 21:55|
|Last Modified:||26 Dec 2012 12:43|
Repository Staff Only: item control page