Variation in XANES in biotite as a function of orientation, crystal composition, and metamorphic history
Microscale analysis of ferrous:ferric iron ratios in silicate minerals has the potential to constrain geological processes but has proved challenging because textural information and spatial resolution are limited with bulk techniques, and in situ methods have limited spatial resolution. Synchrotron...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
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Mineralogical Society of America
2014
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| Online Access: | http://hdl.handle.net/20.500.11937/39843 |
| _version_ | 1848755704361385984 |
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| author | Evans, Katy Dyar, M. Reddy, Steven Lanzirotti, A. Adams, D. Tailby, N. |
| author_facet | Evans, Katy Dyar, M. Reddy, Steven Lanzirotti, A. Adams, D. Tailby, N. |
| author_sort | Evans, Katy |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Microscale analysis of ferrous:ferric iron ratios in silicate minerals has the potential to constrain geological processes but has proved challenging because textural information and spatial resolution are limited with bulk techniques, and in situ methods have limited spatial resolution. Synchrotron methods, such as XANES, have been hampered by the sensitivity of spectra to crystal orientation and matrix effects. In an attempt to break this nexus, biotites from Tanzania were characterized with a combination of optical microscopy, electron microprobe, Mössbauer analysis, electron backscatter diffraction (EBSD) and X-ray absorption near edge structure (XANES) spectroscopy. Pre-edge and edge characteristics of the FeKa absorption feature were compared to orientation information derived by EBSD and ferric iron content derived from Mössbauer analysis. Statistically significant correlations between measured spectral features and optic/crystallographic orientation were observed for individual samples. However, orientation corrections derived from these correlations did not reduce the uncertainty in Fe3+/Fetot. The observations are consistent with matrix- and ordering-dependency of the XANES features, and further work is necessary if a general formulation for orientation corrections is to be devised. |
| first_indexed | 2025-11-14T09:00:32Z |
| format | Journal Article |
| id | curtin-20.500.11937-39843 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:00:32Z |
| publishDate | 2014 |
| publisher | Mineralogical Society of America |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-398432017-10-02T02:28:09Z Variation in XANES in biotite as a function of orientation, crystal composition, and metamorphic history Evans, Katy Dyar, M. Reddy, Steven Lanzirotti, A. Adams, D. Tailby, N. orientation Fe biotite oxidation XANES Microscale analysis of ferrous:ferric iron ratios in silicate minerals has the potential to constrain geological processes but has proved challenging because textural information and spatial resolution are limited with bulk techniques, and in situ methods have limited spatial resolution. Synchrotron methods, such as XANES, have been hampered by the sensitivity of spectra to crystal orientation and matrix effects. In an attempt to break this nexus, biotites from Tanzania were characterized with a combination of optical microscopy, electron microprobe, Mössbauer analysis, electron backscatter diffraction (EBSD) and X-ray absorption near edge structure (XANES) spectroscopy. Pre-edge and edge characteristics of the FeKa absorption feature were compared to orientation information derived by EBSD and ferric iron content derived from Mössbauer analysis. Statistically significant correlations between measured spectral features and optic/crystallographic orientation were observed for individual samples. However, orientation corrections derived from these correlations did not reduce the uncertainty in Fe3+/Fetot. The observations are consistent with matrix- and ordering-dependency of the XANES features, and further work is necessary if a general formulation for orientation corrections is to be devised. 2014 Journal Article http://hdl.handle.net/20.500.11937/39843 10.2138/am.2014.4222 Mineralogical Society of America fulltext |
| spellingShingle | orientation Fe biotite oxidation XANES Evans, Katy Dyar, M. Reddy, Steven Lanzirotti, A. Adams, D. Tailby, N. Variation in XANES in biotite as a function of orientation, crystal composition, and metamorphic history |
| title | Variation in XANES in biotite as a function of orientation, crystal composition, and metamorphic history |
| title_full | Variation in XANES in biotite as a function of orientation, crystal composition, and metamorphic history |
| title_fullStr | Variation in XANES in biotite as a function of orientation, crystal composition, and metamorphic history |
| title_full_unstemmed | Variation in XANES in biotite as a function of orientation, crystal composition, and metamorphic history |
| title_short | Variation in XANES in biotite as a function of orientation, crystal composition, and metamorphic history |
| title_sort | variation in xanes in biotite as a function of orientation, crystal composition, and metamorphic history |
| topic | orientation Fe biotite oxidation XANES |
| url | http://hdl.handle.net/20.500.11937/39843 |