Behavior of iron in (Mg,Fe)SiO[subscript 3] post-perovskite assemblages at Mbar pressures
The electronic environment of the iron sites in postperovskite (PPv) structured ({sup 57}Fe,Mg)SiO{sub 3} has been measured in-situ at 1.12 and 1.19 Mbar at room temperature using {sup 57}Fe synchrotron Moessbauer 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{sup 3+}-like site in a high spin state. The second site is characterized by a small negative isomer shift with respect to {alpha}-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 coexisting 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.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1005683
- Journal Information:
- Geophys. Res. Lett., Vol. 36, Issue 2009; ISSN 0094-8276
- Country of Publication:
- United States
- Language:
- ENGLISH
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