Phase transitions in orthopyroxene (En90) to 49GPa from single-crystal X-ray diffraction
Author(s): Finkelstein, Gregory J; Dera, Przemyslaw K; Duffy, Thomas S
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Full metadata record
DC Field | Value | Language |
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dc.contributor.author | Finkelstein, Gregory J | - |
dc.contributor.author | Dera, Przemyslaw K | - |
dc.contributor.author | Duffy, Thomas S | - |
dc.date.accessioned | 2023-12-11T17:42:01Z | - |
dc.date.available | 2023-12-11T17:42:01Z | - |
dc.date.issued | 2015-07 | en_US |
dc.identifier.citation | Finkelstein, Gregory J., Przemyslaw K. Dera, and Thomas S. Duffy. "Phase transitions in orthopyroxene (En90) to 49 GPa from single-crystal X-ray diffraction." Physics of the Earth and Planetary Interiors 244 (2015): 78-86. doi:10.1016/j.pepi.2014.10.009. | en_US |
dc.identifier.issn | 0031-9201 | - |
dc.identifier.uri | https://manuscript.elsevier.com/S0031920114002209/pdf/S0031920114002209.pdf | - |
dc.identifier.uri | http://arks.princeton.edu/ark:/88435/pr1qv3c386 | - |
dc.description.abstract | Synchrotron-based high-pressure single-crystal X-ray diffraction experiments were conducted on ∼Mg0.9Fe0.1SiO3 (En90) orthopyroxene crystals at room temperature to a maximum pressure of 48.5 GPa. The sample was compressed in a diamond anvil cell with a neon pressure-transmitting medium and a gold pressure calibrant. In addition to the previously described orthopyroxene to β-opx transition (designated HPCEN2 in previous studies), we observe two further phase transitions at 29.9 GPa and 40.3 GPa. However, we do not observe the γ-opx phase recently described in an Fe-rich orthopyroxene composition. The structures of both of the new phases were solved in space group Pca21. While their Mg–O layers remain pyroxene-like, their Si–O layers transform in a stepwise fashion to akimotoite-like sheets, with sites in 4-, 4+1-, or 6-fold coordination, depending on the specific structure and layer. Due to the increased Si–O coordination number, we designate the new structures α- and β-post-orthopyroxene (α-popx and β-popx). α-popx has one Si–O layer that is entirely tetrahedral, and one layer that contains both tetrahedra and 4+1-coordinated Si in distorted square pyramids. β-popx retains the mixed 4- and 4+1-coordinated Si layer found in α-popx, while the other Si layer adopts fully octahedral coordination. The α- and β-popx structures show a progressive transformation towards the arrangement of Si layers found in akimotoite, a potentially important phase in the earth’s transition zone. Metastable transformations in pyroxenes are of interest for understanding possible metastability in geological environments such as subducting slabs and meteorite impacts. | en_US |
dc.format.extent | 78 - 86 | en_US |
dc.language | English | en_US |
dc.language.iso | en_US | en_US |
dc.relation.ispartof | Physics of the Earth and Planetary Interiors | en_US |
dc.rights | Author's manuscript | en_US |
dc.title | Phase transitions in orthopyroxene (En90) to 49GPa from single-crystal X-ray diffraction | en_US |
dc.type | Journal Article | en_US |
dc.identifier.doi | doi:10.1016/j.pepi.2014.10.009 | - |
pu.type.symplectic | http://www.symplectic.co.uk/publications/atom-terms/1.0/journal-article | en_US |
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