Spherulite crystallization induces Fe-redox redistribution in silicic melt
International audience Rhyolitic obsidians from Krafla volcano, Iceland, record the interaction between mobile hydrous species liberated during crystal growth and the reduction of ferric iron in the silicate melt. We performed synchrotron µ-FTIR and µ-XANES measurements along a transect extending fr...
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Online Access: | https://insu.hal.science/insu-00442797 https://insu.hal.science/insu-00442797/document https://insu.hal.science/insu-00442797/file/Castro-ChemicalGeology-2009.pdf https://doi.org/10.1016/j.chemgeo.2009.09.006 |
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ftunivpoitiers:oai:HAL:insu-00442797v1 2024-09-15T18:14:04+00:00 Spherulite crystallization induces Fe-redox redistribution in silicic melt Castro, Jonathan M. Cottrell, Elizabeth Tuffen, H. Logan, Amelia V. Kelley, Katherine A. Institut des Sciences de la Terre d'Orléans (ISTO) Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS) Department of Mineral Sciences Washington Smithsonian Institution Department of Environmental Science Lancaster Lancaster University Graduate School of Oceanography Narragansett University of Rhode Island (URI) 2009 https://insu.hal.science/insu-00442797 https://insu.hal.science/insu-00442797/document https://insu.hal.science/insu-00442797/file/Castro-ChemicalGeology-2009.pdf https://doi.org/10.1016/j.chemgeo.2009.09.006 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.chemgeo.2009.09.006 insu-00442797 https://insu.hal.science/insu-00442797 https://insu.hal.science/insu-00442797/document https://insu.hal.science/insu-00442797/file/Castro-ChemicalGeology-2009.pdf doi:10.1016/j.chemgeo.2009.09.006 info:eu-repo/semantics/OpenAccess ISSN: 0009-2541 Chemical Geology https://insu.hal.science/insu-00442797 Chemical Geology, 2009, 268 (3-4), pp.272-280. ⟨10.1016/j.chemgeo.2009.09.006⟩ Obsidian Spherulite Oxidation–reduction FTIR XANES [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology [SDE.MCG]Environmental Sciences/Global Changes info:eu-repo/semantics/article Journal articles 2009 ftunivpoitiers https://doi.org/10.1016/j.chemgeo.2009.09.006 2024-07-18T03:12:20Z International audience Rhyolitic obsidians from Krafla volcano, Iceland, record the interaction between mobile hydrous species liberated during crystal growth and the reduction of ferric iron in the silicate melt. We performed synchrotron µ-FTIR and µ-XANES measurements along a transect extending from a spherulite into optically distinct colorless and brown glass zones. Measurements show that the colorless glass is enriched in OH groups and depleted in ferric iron, while the brown glass shows the opposite relationship. The color shift between brown and clear glass is sharp, suggesting that the colorless glass zone was produced by a redox front that originated from the spherulite margin and moved through surrounding melt during crystallization. We conclude that the most likely reducing agent is hydrogen, produced by magnetite crystallization within the spherulite. The Krafla obsidians dramatically capture redox disequilibrium on the micoscale and highlight the importance of hydrous fluid liberation and late-stage crystallization to the redox signature of glassy lavas. Article in Journal/Newspaper Iceland Université de Poitiers: Publications de nos chercheurs.ses (HAL) Chemical Geology 268 3-4 272 280 |
institution |
Open Polar |
collection |
Université de Poitiers: Publications de nos chercheurs.ses (HAL) |
op_collection_id |
ftunivpoitiers |
language |
English |
topic |
Obsidian Spherulite Oxidation–reduction FTIR XANES [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology [SDE.MCG]Environmental Sciences/Global Changes |
spellingShingle |
Obsidian Spherulite Oxidation–reduction FTIR XANES [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology [SDE.MCG]Environmental Sciences/Global Changes Castro, Jonathan M. Cottrell, Elizabeth Tuffen, H. Logan, Amelia V. Kelley, Katherine A. Spherulite crystallization induces Fe-redox redistribution in silicic melt |
topic_facet |
Obsidian Spherulite Oxidation–reduction FTIR XANES [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology [SDE.MCG]Environmental Sciences/Global Changes |
description |
International audience Rhyolitic obsidians from Krafla volcano, Iceland, record the interaction between mobile hydrous species liberated during crystal growth and the reduction of ferric iron in the silicate melt. We performed synchrotron µ-FTIR and µ-XANES measurements along a transect extending from a spherulite into optically distinct colorless and brown glass zones. Measurements show that the colorless glass is enriched in OH groups and depleted in ferric iron, while the brown glass shows the opposite relationship. The color shift between brown and clear glass is sharp, suggesting that the colorless glass zone was produced by a redox front that originated from the spherulite margin and moved through surrounding melt during crystallization. We conclude that the most likely reducing agent is hydrogen, produced by magnetite crystallization within the spherulite. The Krafla obsidians dramatically capture redox disequilibrium on the micoscale and highlight the importance of hydrous fluid liberation and late-stage crystallization to the redox signature of glassy lavas. |
author2 |
Institut des Sciences de la Terre d'Orléans (ISTO) Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS) Department of Mineral Sciences Washington Smithsonian Institution Department of Environmental Science Lancaster Lancaster University Graduate School of Oceanography Narragansett University of Rhode Island (URI) |
format |
Article in Journal/Newspaper |
author |
Castro, Jonathan M. Cottrell, Elizabeth Tuffen, H. Logan, Amelia V. Kelley, Katherine A. |
author_facet |
Castro, Jonathan M. Cottrell, Elizabeth Tuffen, H. Logan, Amelia V. Kelley, Katherine A. |
author_sort |
Castro, Jonathan M. |
title |
Spherulite crystallization induces Fe-redox redistribution in silicic melt |
title_short |
Spherulite crystallization induces Fe-redox redistribution in silicic melt |
title_full |
Spherulite crystallization induces Fe-redox redistribution in silicic melt |
title_fullStr |
Spherulite crystallization induces Fe-redox redistribution in silicic melt |
title_full_unstemmed |
Spherulite crystallization induces Fe-redox redistribution in silicic melt |
title_sort |
spherulite crystallization induces fe-redox redistribution in silicic melt |
publisher |
HAL CCSD |
publishDate |
2009 |
url |
https://insu.hal.science/insu-00442797 https://insu.hal.science/insu-00442797/document https://insu.hal.science/insu-00442797/file/Castro-ChemicalGeology-2009.pdf https://doi.org/10.1016/j.chemgeo.2009.09.006 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
ISSN: 0009-2541 Chemical Geology https://insu.hal.science/insu-00442797 Chemical Geology, 2009, 268 (3-4), pp.272-280. ⟨10.1016/j.chemgeo.2009.09.006⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.chemgeo.2009.09.006 insu-00442797 https://insu.hal.science/insu-00442797 https://insu.hal.science/insu-00442797/document https://insu.hal.science/insu-00442797/file/Castro-ChemicalGeology-2009.pdf doi:10.1016/j.chemgeo.2009.09.006 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1016/j.chemgeo.2009.09.006 |
container_title |
Chemical Geology |
container_volume |
268 |
container_issue |
3-4 |
container_start_page |
272 |
op_container_end_page |
280 |
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1810451844007198720 |