Details
| Original language | English |
|---|---|
| Pages (from-to) | 331-340 |
| Number of pages | 10 |
| Journal | Schweizerische Mineralogische und Petrographische Mitteilungen |
| Volume | 83 |
| Issue number | 3 |
| Publication status | Published - Nov 2003 |
Abstract
In the OH-stretching range, most of the micas studied exhibit partial dioctahedral character, which increases with increasing fO2. At both the Ni-NiO and wüstite-magnetite oxygen buffers, our spectra of annite indicate the presence of aluminum and Fe3+ in octahedral sites, which is required to articulate the octahedral layers. The decomposition of the infrared spectra allows one to redefine the assignment of annite absorption bands. Three V-bands of " dioctahedral-type" (in the range 3580-3520 cm-1) are characterized by the bulk number of charges of the two adjacent cations: two bands due to OH groups adjacent to an octahedral vacancy and bonded to Fe2+Al3+□ or Fe2+Fe 3+□ (range 3580-3540 cm-1); a band due to OH groups bonded to Fe3+Fe3+□ at 3530 cm -1. For Al-rich annite, the band assigned to OH-Fe 2+Fe3+□ is replaced by a band due to OH groups adjacent to Fe3+Al3+□. An 8-fold charged environment OH-Fe2+Al3+Al3+ does not seem likely in the micas studied. At higher wavenumbers, two I-bands of "trioctahedral-type" (OH-Fe2+Fe 2+Fe3+ and Fe2+Fe2+Al 3+) and one N-band corresponding to OH-Fe 2+Fe2+Fe2+ have been resolved. For all trioctahedral-type bands (I- and N-bands), a systematic shift is observed toward lower wavenumbers with increasing aluminum content of the mica. When compared to N- or I-bands, V-bands show an opposite behaviour.
Keywords
- 8-fold charged, Annite, Ferrous aluminous biotites, OH-groups, OH-stretching vibrations
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geology
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Schweizerische Mineralogische und Petrographische Mitteilungen, Vol. 83, No. 3, 11.2003, p. 331-340.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Infrared spectra of annite in the OH-stretching vibrational range
AU - Boukili, Boubker
AU - Holtz, François
AU - Robert, Jean Louis
AU - Joriou, Mohammed
AU - Bény, Jean Michel
AU - Naji, Mohamed
N1 - Copyright: Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2003/11
Y1 - 2003/11
N2 - In the OH-stretching range, most of the micas studied exhibit partial dioctahedral character, which increases with increasing fO2. At both the Ni-NiO and wüstite-magnetite oxygen buffers, our spectra of annite indicate the presence of aluminum and Fe3+ in octahedral sites, which is required to articulate the octahedral layers. The decomposition of the infrared spectra allows one to redefine the assignment of annite absorption bands. Three V-bands of " dioctahedral-type" (in the range 3580-3520 cm-1) are characterized by the bulk number of charges of the two adjacent cations: two bands due to OH groups adjacent to an octahedral vacancy and bonded to Fe2+Al3+□ or Fe2+Fe 3+□ (range 3580-3540 cm-1); a band due to OH groups bonded to Fe3+Fe3+□ at 3530 cm -1. For Al-rich annite, the band assigned to OH-Fe 2+Fe3+□ is replaced by a band due to OH groups adjacent to Fe3+Al3+□. An 8-fold charged environment OH-Fe2+Al3+Al3+ does not seem likely in the micas studied. At higher wavenumbers, two I-bands of "trioctahedral-type" (OH-Fe2+Fe 2+Fe3+ and Fe2+Fe2+Al 3+) and one N-band corresponding to OH-Fe 2+Fe2+Fe2+ have been resolved. For all trioctahedral-type bands (I- and N-bands), a systematic shift is observed toward lower wavenumbers with increasing aluminum content of the mica. When compared to N- or I-bands, V-bands show an opposite behaviour.
AB - In the OH-stretching range, most of the micas studied exhibit partial dioctahedral character, which increases with increasing fO2. At both the Ni-NiO and wüstite-magnetite oxygen buffers, our spectra of annite indicate the presence of aluminum and Fe3+ in octahedral sites, which is required to articulate the octahedral layers. The decomposition of the infrared spectra allows one to redefine the assignment of annite absorption bands. Three V-bands of " dioctahedral-type" (in the range 3580-3520 cm-1) are characterized by the bulk number of charges of the two adjacent cations: two bands due to OH groups adjacent to an octahedral vacancy and bonded to Fe2+Al3+□ or Fe2+Fe 3+□ (range 3580-3540 cm-1); a band due to OH groups bonded to Fe3+Fe3+□ at 3530 cm -1. For Al-rich annite, the band assigned to OH-Fe 2+Fe3+□ is replaced by a band due to OH groups adjacent to Fe3+Al3+□. An 8-fold charged environment OH-Fe2+Al3+Al3+ does not seem likely in the micas studied. At higher wavenumbers, two I-bands of "trioctahedral-type" (OH-Fe2+Fe 2+Fe3+ and Fe2+Fe2+Al 3+) and one N-band corresponding to OH-Fe 2+Fe2+Fe2+ have been resolved. For all trioctahedral-type bands (I- and N-bands), a systematic shift is observed toward lower wavenumbers with increasing aluminum content of the mica. When compared to N- or I-bands, V-bands show an opposite behaviour.
KW - 8-fold charged
KW - Annite
KW - Ferrous aluminous biotites
KW - OH-groups
KW - OH-stretching vibrations
UR - http://www.scopus.com/inward/record.url?scp=16344368118&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:16344368118
VL - 83
SP - 331
EP - 340
JO - Schweizerische Mineralogische und Petrographische Mitteilungen
JF - Schweizerische Mineralogische und Petrographische Mitteilungen
SN - 0036-7699
IS - 3
ER -