X-ray diffraction study of iron partitioning between α and γ phases of the (Mg,Fe)2SiO4 system
✍ Scribed by Jiuhua Chen; Donald J. Weidner
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 405 KB
- Volume
- 239
- Category
- Article
- ISSN
- 0378-4371
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✦ Synopsis
We have studied the time dependence of the Fe partitioning between olivine and ringwoodite at pressures and temperatures where the phases coexist. Using SAM85, a cubic anvil high-pressure apparatus with synchrotron radiation, we collected energy dispersive X-ray diffraction spectra as a function of time at 900°C/ll.5GPa, lll7°C/ll.7GPa and 900°C/ll.IGPa. These data were analyzed with Rietveld refinement techniques to determine very accurate lattice parameters and phase fractions. The time evolution of the sample volume indicates that iron-magnesium exchange occurs at lll7°C on the scale of minutes, but does not evolve at 900°C. Using unit cell volume as a measure of iron content, the Fe partitioning in olivine and ringwoodite increases by 4% and 5%, respectively within 1 h at 1117°C while the phase fraction increases 10% for olivine and decreases 10% for ringwoodite.
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## Denmuk (Rectiwd in UK 13 Nowmber 1929