Jackson, Jennifer M. and Sturhahn, Wolfgang and Tschauner, Oliver and Lerche, Michael and Fei, Yingwei (2009) Behavior of iron in (Mg,Fe)SiO_3 post-perovskite assemblages at Mbar pressures. Geophysical Research Letters, 36 . L10301. ISSN 0094-8276 http://resolver.caltech.edu/CaltechAUTHORS:20090713-085032457
- Published Version
Restricted to Repository administrators only
See Usage Policy.
Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20090713-085032457
The electronic environment of the iron sites in post-perovskite (PPv) structured (^(57)Fe,Mg)SiO_3 has been measured in-situ at 1.12 and 1.19 Mbar at room temperature using ^(57)Fe synchrotron Mössbauer spectroscopy. Evaluation of the time spectra reveals two distinct iron sites, which are well distinguished by their hyperfine fields. The dominant site is consistent with an Fe^(3+)-like site in a high spin state. The second site is characterized by a small negative isomer shift with respect to α-iron and no quadrupole splitting, consistent with a metallic iron phase. Combined with SEM/EDS analyses of the quenched assemblage, our results are consistent with the presence of a metallic iron phase co-existing with a ferric-rich PPv. Such a reaction pathway may aid in our understanding of the chemical evolution of Earth's core-mantle-boundary region.
|Additional Information:||© 2009 American Geophysical Union. Received 18 February 2009; accepted 30 March 2009; published 19 May 2009. We thank J. Zhao for technical assistance, D. Stevenson for discussions, D. Adams and two anonymous reviewers for their comments. Support for this work was provided in part by the National Science Foundation (NSF) EAR 0711542 and Caltech (J.M.J.), NSF-EAR 0552010 and NNSA Cooperative Agreement DOE-FC52-06NA27684 (O.T.), the U.S. DOE, Office of Science, BES under DE-AC02- 06CH11357, and COMPRES under NSF Cooperative Agreement EAR 06-49658. X-ray diffraction experiments were performed at HPCAT (Sector 16, APS). SEM and EDS analyses were carried out at the Caltech GPS Division Analytical Facility (MRSEC Program of the NSF under DMR-0080065).|
|Subject Keywords:||post-perovskite; iron; Mössbauer|
|Official Citation:||Jackson, J. M., W. Sturhahn, O. Tschauner, M. Lerche, and Y. Fei (2009), Behavior of iron in (Mg,Fe)SiO3 post-perovskite assemblages at Mbar pressures, Geophys. Res. Lett., 36, L10301, doi:10.1029/2009GL037815.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||11 Aug 2009 18:39|
|Last Modified:||26 Dec 2012 11:04|
Repository Staff Only: item control page