A framework for quantitative in situ evaluation of coupled substitutions between H<sup>+</sup> and trace elements in natural rutile
<p>The coupling behaviour of H<span class="inline-formula"><sup>+</sup></span> and trace elements in rutile has been studied using in situ polarised Fourier transform infrared (FTIR) spectroscopy and laser ablation inductively coupled plasma mass spectrometry...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-04-01
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| Series: | European Journal of Mineralogy |
| Online Access: | https://ejm.copernicus.org/articles/35/243/2023/ejm-35-243-2023.pdf |
| _version_ | 1797852042369171456 |
|---|---|
| author | M. Lueder R. Tamblyn J. Hermann |
| author_facet | M. Lueder R. Tamblyn J. Hermann |
| author_sort | M. Lueder |
| collection | DOAJ |
| description | <p>The coupling behaviour of H<span class="inline-formula"><sup>+</sup></span> and trace elements in rutile has been
studied using in situ polarised Fourier transform infrared (FTIR)
spectroscopy and laser ablation inductively coupled plasma mass spectrometry
(LA–ICP–MS) analysis. H<span class="inline-formula"><sub>2</sub></span>O contents in rutile can be precisely and
accurately quantified from polarised FTIR measurements on single grains in
situ. The benefits of this novel approach compared to traditional
quantification methods are the preservation of textural context and
heterogeneities of water in rutile. Rutile from six different geological
environments shows H<span class="inline-formula"><sub>2</sub></span>O contents varying between <span class="inline-formula">∼</span> 50–2200 <span class="inline-formula">µ</span>g g<span class="inline-formula"><sup>−1</sup></span>, with large intra-grain variabilities for vein-related samples
with H<span class="inline-formula"><sub>2</sub></span>O contents between <span class="inline-formula">∼</span> 500 and
<span class="inline-formula">∼</span> 2200 <span class="inline-formula">µ</span>g g<span class="inline-formula"><sup>−1</sup></span>. From FTIR peak deconvolutions, six distinct
OH absorption bands have been identified at <span class="inline-formula">∼</span> 3280, <span class="inline-formula">∼</span> 3295, <span class="inline-formula">∼</span> 3324,
<span class="inline-formula">∼</span> 3345, <span class="inline-formula">∼</span> 3370, and
<span class="inline-formula">∼</span> 3390 cm<span class="inline-formula"><sup>−1</sup></span> that can be related to coupled substitutions
with Ti<span class="inline-formula"><sup>3+</sup></span>, Fe<span class="inline-formula"><sup>3+</sup></span>, Al<span class="inline-formula"><sup>3+</sup></span>, Mg<span class="inline-formula"><sup>2+</sup></span>, Fe<span class="inline-formula"><sup>2+</sup></span>, and Cr<span class="inline-formula"><sup>2+</sup></span>,
respectively. Rutile from eclogite samples displays the dominant exchange
reactions of Ti<span class="inline-formula"><sup>4+</sup></span> <span class="inline-formula">→</span> Ti<span class="inline-formula"><sup>3+</sup></span>, Fe<span class="inline-formula"><sup>3+</sup></span> <span class="inline-formula">+</span> H<span class="inline-formula"><sup>+</sup></span>, whereas
rutile in a whiteschist shows mainly Ti<span class="inline-formula"><sup>4+</sup></span> <span class="inline-formula">→</span> Al<span class="inline-formula"><sup>3+</sup></span> <span class="inline-formula">+</span> H<span class="inline-formula"><sup>+</sup></span>.
Trace-element-dependent H<span class="inline-formula"><sup>+</sup></span> contents combined with LA–ICP–MS
trace-element data reveal the significant importance of H<span class="inline-formula"><sup>+</sup></span> for charge
balance and trace-element coupling with trivalent cations. Trivalent cations
are the most abundant impurities in rutile, and there is not enough H<span class="inline-formula"><sup>+</sup></span>
and pentavalent cations like Nb and Ta for a complete charge balance,
indicating that additionally oxygen vacancies are needed for charge
balancing trivalent cations. Valance states of multivalent trace elements
can be inferred from deconvoluted FTIR spectra. Titanium occurs at 0.03 ‰–7.6 ‰ as Ti<span class="inline-formula"><sup>3+</sup></span>, Fe, and Cr are preferentially
incorporated as Fe<span class="inline-formula"><sup>3+</sup></span> and Cr<span class="inline-formula"><sup>3+</sup></span> over Fe<span class="inline-formula"><sup>2+</sup></span> and Cr<span class="inline-formula"><sup>2+</sup></span>, and V
most likely occurs as V<span class="inline-formula"><sup>4+</sup></span>. This opens the possibility of H<span class="inline-formula"><sup>+</sup></span> in rutile as
a potential indicator of oxygen fugacity of metamorphic and subduction-zone
fluids, with the ratio between Ti<span class="inline-formula"><sup>3+</sup></span>- and Fe<span class="inline-formula"><sup>3+</sup></span>-related H<span class="inline-formula"><sup>+</sup></span>
contents being most promising.</p> |
| first_indexed | 2024-04-09T19:27:37Z |
| format | Article |
| id | doaj.art-5855a2e64fe94f2d856044433dec2247 |
| institution | Directory Open Access Journal |
| issn | 0935-1221 1617-4011 |
| language | English |
| last_indexed | 2024-04-09T19:27:37Z |
| publishDate | 2023-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | European Journal of Mineralogy |
| spelling | doaj.art-5855a2e64fe94f2d856044433dec22472023-04-05T05:32:25ZengCopernicus PublicationsEuropean Journal of Mineralogy0935-12211617-40112023-04-013524326510.5194/ejm-35-243-2023A framework for quantitative in situ evaluation of coupled substitutions between H<sup>+</sup> and trace elements in natural rutileM. LuederR. TamblynJ. Hermann<p>The coupling behaviour of H<span class="inline-formula"><sup>+</sup></span> and trace elements in rutile has been studied using in situ polarised Fourier transform infrared (FTIR) spectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) analysis. H<span class="inline-formula"><sub>2</sub></span>O contents in rutile can be precisely and accurately quantified from polarised FTIR measurements on single grains in situ. The benefits of this novel approach compared to traditional quantification methods are the preservation of textural context and heterogeneities of water in rutile. Rutile from six different geological environments shows H<span class="inline-formula"><sub>2</sub></span>O contents varying between <span class="inline-formula">∼</span> 50–2200 <span class="inline-formula">µ</span>g g<span class="inline-formula"><sup>−1</sup></span>, with large intra-grain variabilities for vein-related samples with H<span class="inline-formula"><sub>2</sub></span>O contents between <span class="inline-formula">∼</span> 500 and <span class="inline-formula">∼</span> 2200 <span class="inline-formula">µ</span>g g<span class="inline-formula"><sup>−1</sup></span>. From FTIR peak deconvolutions, six distinct OH absorption bands have been identified at <span class="inline-formula">∼</span> 3280, <span class="inline-formula">∼</span> 3295, <span class="inline-formula">∼</span> 3324, <span class="inline-formula">∼</span> 3345, <span class="inline-formula">∼</span> 3370, and <span class="inline-formula">∼</span> 3390 cm<span class="inline-formula"><sup>−1</sup></span> that can be related to coupled substitutions with Ti<span class="inline-formula"><sup>3+</sup></span>, Fe<span class="inline-formula"><sup>3+</sup></span>, Al<span class="inline-formula"><sup>3+</sup></span>, Mg<span class="inline-formula"><sup>2+</sup></span>, Fe<span class="inline-formula"><sup>2+</sup></span>, and Cr<span class="inline-formula"><sup>2+</sup></span>, respectively. Rutile from eclogite samples displays the dominant exchange reactions of Ti<span class="inline-formula"><sup>4+</sup></span> <span class="inline-formula">→</span> Ti<span class="inline-formula"><sup>3+</sup></span>, Fe<span class="inline-formula"><sup>3+</sup></span> <span class="inline-formula">+</span> H<span class="inline-formula"><sup>+</sup></span>, whereas rutile in a whiteschist shows mainly Ti<span class="inline-formula"><sup>4+</sup></span> <span class="inline-formula">→</span> Al<span class="inline-formula"><sup>3+</sup></span> <span class="inline-formula">+</span> H<span class="inline-formula"><sup>+</sup></span>. Trace-element-dependent H<span class="inline-formula"><sup>+</sup></span> contents combined with LA–ICP–MS trace-element data reveal the significant importance of H<span class="inline-formula"><sup>+</sup></span> for charge balance and trace-element coupling with trivalent cations. Trivalent cations are the most abundant impurities in rutile, and there is not enough H<span class="inline-formula"><sup>+</sup></span> and pentavalent cations like Nb and Ta for a complete charge balance, indicating that additionally oxygen vacancies are needed for charge balancing trivalent cations. Valance states of multivalent trace elements can be inferred from deconvoluted FTIR spectra. Titanium occurs at 0.03 ‰–7.6 ‰ as Ti<span class="inline-formula"><sup>3+</sup></span>, Fe, and Cr are preferentially incorporated as Fe<span class="inline-formula"><sup>3+</sup></span> and Cr<span class="inline-formula"><sup>3+</sup></span> over Fe<span class="inline-formula"><sup>2+</sup></span> and Cr<span class="inline-formula"><sup>2+</sup></span>, and V most likely occurs as V<span class="inline-formula"><sup>4+</sup></span>. This opens the possibility of H<span class="inline-formula"><sup>+</sup></span> in rutile as a potential indicator of oxygen fugacity of metamorphic and subduction-zone fluids, with the ratio between Ti<span class="inline-formula"><sup>3+</sup></span>- and Fe<span class="inline-formula"><sup>3+</sup></span>-related H<span class="inline-formula"><sup>+</sup></span> contents being most promising.</p>https://ejm.copernicus.org/articles/35/243/2023/ejm-35-243-2023.pdf |
| spellingShingle | M. Lueder R. Tamblyn J. Hermann A framework for quantitative in situ evaluation of coupled substitutions between H<sup>+</sup> and trace elements in natural rutile European Journal of Mineralogy |
| title | A framework for quantitative in situ evaluation of coupled substitutions between H<sup>+</sup> and trace elements in natural rutile |
| title_full | A framework for quantitative in situ evaluation of coupled substitutions between H<sup>+</sup> and trace elements in natural rutile |
| title_fullStr | A framework for quantitative in situ evaluation of coupled substitutions between H<sup>+</sup> and trace elements in natural rutile |
| title_full_unstemmed | A framework for quantitative in situ evaluation of coupled substitutions between H<sup>+</sup> and trace elements in natural rutile |
| title_short | A framework for quantitative in situ evaluation of coupled substitutions between H<sup>+</sup> and trace elements in natural rutile |
| title_sort | framework for quantitative in situ evaluation of coupled substitutions between h sup sup and trace elements in natural rutile |
| url | https://ejm.copernicus.org/articles/35/243/2023/ejm-35-243-2023.pdf |
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