Abstract
The solubility of hydrogen in Fe2O3-doped rutile and TiO2 (II) at 1100 degreesC has been experimentally determined. H incorporation in rutile is coupled to substitution of Fe3+ onto the octahedral Ti4+ site. In contrast, TiO2 (II) contains no structurally-incorporated hydrogen. The dominant Fe3+ incorporation mechanism in both phases is unrelated to H content, and involves substitution of Fe3+ onto octahedral Ti4+ sites, charge-balanced by oxygen vacancies. Substitution of Fe2O3 into TiO2 (II) stabilizes the structure to much lower pressures than in the pure TiO2 system. Results indicate that Al-bearing stishovite could act as an important carrier of water in subducting oceanic crust, but that formation of the post-stishovite phase with the alpha-PbO2 structure would represent a significant dehydration event at the base of the lower mantle.
Original language | English |
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Article number | 04610 |
Number of pages | 5 |
Journal | Geophysical Research Letters |
Volume | 31 |
Issue number | 4 |
DOIs | |
Publication status | Published - 24 Feb 2004 |
Keywords / Materials (for Non-textual outputs)
- WATER
- STISHOVITE
- MINERALS
- ABSORPTION
- SUBSTITUTION
- MORB