Abstract
We determined phase relations in FeCr2O4at 12-28 GPa and 800-1600 °C using a multi-anvil apparatus. At 12-16 GPa, FeCr2O4spinel (chromite) first dissociates into two phases: a new Fe2Cr2O5phase + Cr2O3with the corundum structure. At 17-18 GPa, the two phases combine into CaFe2O4-type and CaTi2O4-type FeCr2O4below and above 1300 °C, respectively. Structure refinements using synchrotron X-ray powder diffraction data confirmed the CaTi2O4-structured FeCr2O4(Cmcm), and indicated that the Fe2Cr2O5phase is isostructural to a modified ludwigite-type Mg2Al2O5(Pbam). In situ high-pressure high-temperature X-ray diffraction experiments showed that CaFe2O4-type FeCr2O4is unquenchable and is converted into another FeCr2O4phase on decompression. Structural analysis based on synchrotron X-ray powder diffraction data with transmission electron microscopic observation clarified that the recovered FeCr2O4phase has a new structure related to CaFe2O4-type. The high-pressure phase relations in FeCr2O4reveal that natural FeCr2O4-rich phases of CaFe2O4-and CaTi2O4-type structures found in the shocked Suizhou meteorite were formed above about 18 GPa at temperature below and above 1300 °C, respectively. The phase relations also suggest that the natural chromitites in the Luobusa ophiolite previously interpreted as formed in the deep-mantle were formed at pressure below 12-16 GPa.
| Original language | English |
|---|---|
| Pages (from-to) | 1788-1797 |
| Number of pages | 10 |
| Journal | American Mineralogist |
| Volume | 99 |
| Issue number | 8-9 |
| DOIs | |
| Publication status | Published - Aug 1 2014 |
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Keywords
- crystal structure
- FeCr2O4
- high pressure
- ophiolite
- phase transition
- Post-spinel
- Rietveld analysis
- shocked meteorite
ASJC Scopus subject areas
- Geochemistry and Petrology
- Geophysics
Cite this
High-pressure phase transitions in FeCr2O4and structure analysis of new post-spinel FeCr2O4and Fe2Cr2O5phases with meteoritical and petrological implications. / Ishii, Takayuki; Kojitani, Hiroshi; Tsukamoto, Shoichi; Fujino, Kiyoshi; Mori, Daisuke; Inaguma, Yoshiyuki; Tsujino, Noriyoshi; Yoshino, Takashi; Yamazaki, Daisuke; Higo, Yuji; Funakoshi, Kenichi; Akaogi, Masaki.
In: American Mineralogist, Vol. 99, No. 8-9, 01.08.2014, p. 1788-1797.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - High-pressure phase transitions in FeCr2O4and structure analysis of new post-spinel FeCr2O4and Fe2Cr2O5phases with meteoritical and petrological implications
AU - Ishii, Takayuki
AU - Kojitani, Hiroshi
AU - Tsukamoto, Shoichi
AU - Fujino, Kiyoshi
AU - Mori, Daisuke
AU - Inaguma, Yoshiyuki
AU - Tsujino, Noriyoshi
AU - Yoshino, Takashi
AU - Yamazaki, Daisuke
AU - Higo, Yuji
AU - Funakoshi, Kenichi
AU - Akaogi, Masaki
PY - 2014/8/1
Y1 - 2014/8/1
N2 - We determined phase relations in FeCr2O4at 12-28 GPa and 800-1600 °C using a multi-anvil apparatus. At 12-16 GPa, FeCr2O4spinel (chromite) first dissociates into two phases: a new Fe2Cr2O5phase + Cr2O3with the corundum structure. At 17-18 GPa, the two phases combine into CaFe2O4-type and CaTi2O4-type FeCr2O4below and above 1300 °C, respectively. Structure refinements using synchrotron X-ray powder diffraction data confirmed the CaTi2O4-structured FeCr2O4(Cmcm), and indicated that the Fe2Cr2O5phase is isostructural to a modified ludwigite-type Mg2Al2O5(Pbam). In situ high-pressure high-temperature X-ray diffraction experiments showed that CaFe2O4-type FeCr2O4is unquenchable and is converted into another FeCr2O4phase on decompression. Structural analysis based on synchrotron X-ray powder diffraction data with transmission electron microscopic observation clarified that the recovered FeCr2O4phase has a new structure related to CaFe2O4-type. The high-pressure phase relations in FeCr2O4reveal that natural FeCr2O4-rich phases of CaFe2O4-and CaTi2O4-type structures found in the shocked Suizhou meteorite were formed above about 18 GPa at temperature below and above 1300 °C, respectively. The phase relations also suggest that the natural chromitites in the Luobusa ophiolite previously interpreted as formed in the deep-mantle were formed at pressure below 12-16 GPa.
AB - We determined phase relations in FeCr2O4at 12-28 GPa and 800-1600 °C using a multi-anvil apparatus. At 12-16 GPa, FeCr2O4spinel (chromite) first dissociates into two phases: a new Fe2Cr2O5phase + Cr2O3with the corundum structure. At 17-18 GPa, the two phases combine into CaFe2O4-type and CaTi2O4-type FeCr2O4below and above 1300 °C, respectively. Structure refinements using synchrotron X-ray powder diffraction data confirmed the CaTi2O4-structured FeCr2O4(Cmcm), and indicated that the Fe2Cr2O5phase is isostructural to a modified ludwigite-type Mg2Al2O5(Pbam). In situ high-pressure high-temperature X-ray diffraction experiments showed that CaFe2O4-type FeCr2O4is unquenchable and is converted into another FeCr2O4phase on decompression. Structural analysis based on synchrotron X-ray powder diffraction data with transmission electron microscopic observation clarified that the recovered FeCr2O4phase has a new structure related to CaFe2O4-type. The high-pressure phase relations in FeCr2O4reveal that natural FeCr2O4-rich phases of CaFe2O4-and CaTi2O4-type structures found in the shocked Suizhou meteorite were formed above about 18 GPa at temperature below and above 1300 °C, respectively. The phase relations also suggest that the natural chromitites in the Luobusa ophiolite previously interpreted as formed in the deep-mantle were formed at pressure below 12-16 GPa.
KW - crystal structure
KW - FeCr2O4
KW - high pressure
KW - ophiolite
KW - phase transition
KW - Post-spinel
KW - Rietveld analysis
KW - shocked meteorite
UR - http://www.scopus.com/inward/record.url?scp=84906996508&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84906996508&partnerID=8YFLogxK
U2 - 10.2138/am.2014.4736
DO - 10.2138/am.2014.4736
M3 - Article
AN - SCOPUS:84906996508
VL - 99
SP - 1788
EP - 1797
JO - American Mineralogist
JF - American Mineralogist
SN - 0003-004X
IS - 8-9
ER -