A new petrogenetic model for low-Ca boninites: Evidence from veined sub-arc xenoliths on melt-mantle interaction and melt fractionation
International audience Low-Ca boninites (LCB) are arc-related magmatic rocks enriched in large ion lithophile elements (LILE), light rare earth elements (LREE), Zr and Hf relative to medium to heavy REE (MREE-HREE). These signatures are commonly attributed to a unique slab-derived agent that metasom...
Published in: | Geochemistry, Geophysics, Geosystems |
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Main Authors: | , |
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2012
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Online Access: | https://hal.science/hal-00793975 https://hal.science/hal-00793975/document https://hal.science/hal-00793975/file/Geochem%20Geophys%20Geosyst%20-%202012%20-%20B%20nard%20-%20A%20new%20petrogenetic%20model%20for%20low%25u2010Ca%20boninites%20Evidence%20from%20veined%20sub%25u2010arc.pdf https://doi.org/10.1029/2012GC004145 |
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ftinsu:oai:HAL:hal-00793975v1 |
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openpolar |
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Open Polar |
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Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
island arc low-Ca boninite mantle xenolith melt-rock interaction modeling [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDE.MCG]Environmental Sciences/Global Changes |
spellingShingle |
island arc low-Ca boninite mantle xenolith melt-rock interaction modeling [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDE.MCG]Environmental Sciences/Global Changes Bénard, A. Ionov, D. A. A new petrogenetic model for low-Ca boninites: Evidence from veined sub-arc xenoliths on melt-mantle interaction and melt fractionation |
topic_facet |
island arc low-Ca boninite mantle xenolith melt-rock interaction modeling [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDE.MCG]Environmental Sciences/Global Changes |
description |
International audience Low-Ca boninites (LCB) are arc-related magmatic rocks enriched in large ion lithophile elements (LILE), light rare earth elements (LREE), Zr and Hf relative to medium to heavy REE (MREE-HREE). These signatures are commonly attributed to a unique slab-derived agent that metasomatized a depleted mantle source but their origin in such an agent remains enigmatic. We report andesite-hosted refractory spinel harzburgite xenoliths from the Kamchatka arc, which contain a series of orthopyroxene-rich veins; these veins range in thickness, the contents of clinopyroxene and amphibole and degrees of reaction with the host. Vein minerals in reaction zones with host harzburgites show progressive depletion in MREE-HREE at constant Zr-Hf and develop patterns (U-shaped REE with Zr-Hf spikes) that mimic those of LCB. Major and trace element modeling suggests that these veins (1) formed from a high-temperature (≥1400°C), MgO-rich (∼30 wt.%) and silicic (∼54 wt.% SiO2) initial melt, strongly depleted in Al2O3, TiO2and alkalis and (2) record fractionation of the initial melt to form hydrous liquids; the initial melt was equilibrated with metasomatized Kamchatka harzburgites and was similar in trace element abundances to island arc tholeiite (LREE-depleted to flat LREE-MREE patterns, low Nb and Ta but no significant Zr-Hf anomalies, high LILE). We argue that primary magmas of LCB formed by fluid-fluxed (LILE-rich and [Nb, Ta]-depleted fluid) melting of a cpx-free, highly refractory (≥30% melt extraction) harzburgitic source similar to arc peridotites from Kamchatka and elsewhere. This peculiar source may explain the distinctive major element features of LCB primary magmas. We propose that the primary magmas of LCB develop their characteristic trace element patterns through fractionation and reaction with refractory peridotites in the mantle wedge. Slab-related components alone may explain the high LILE in LCB but not their distinctive REE patterns and positive Zr-Hf anomalies. |
author2 |
Laboratoire Magmas et Volcans (LMV) Observatoire de Physique du Globe de Clermont-Ferrand (OPGC) Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Bénard, A. Ionov, D. A. |
author_facet |
Bénard, A. Ionov, D. A. |
author_sort |
Bénard, A. |
title |
A new petrogenetic model for low-Ca boninites: Evidence from veined sub-arc xenoliths on melt-mantle interaction and melt fractionation |
title_short |
A new petrogenetic model for low-Ca boninites: Evidence from veined sub-arc xenoliths on melt-mantle interaction and melt fractionation |
title_full |
A new petrogenetic model for low-Ca boninites: Evidence from veined sub-arc xenoliths on melt-mantle interaction and melt fractionation |
title_fullStr |
A new petrogenetic model for low-Ca boninites: Evidence from veined sub-arc xenoliths on melt-mantle interaction and melt fractionation |
title_full_unstemmed |
A new petrogenetic model for low-Ca boninites: Evidence from veined sub-arc xenoliths on melt-mantle interaction and melt fractionation |
title_sort |
new petrogenetic model for low-ca boninites: evidence from veined sub-arc xenoliths on melt-mantle interaction and melt fractionation |
publisher |
HAL CCSD |
publishDate |
2012 |
url |
https://hal.science/hal-00793975 https://hal.science/hal-00793975/document https://hal.science/hal-00793975/file/Geochem%20Geophys%20Geosyst%20-%202012%20-%20B%20nard%20-%20A%20new%20petrogenetic%20model%20for%20low%25u2010Ca%20boninites%20Evidence%20from%20veined%20sub%25u2010arc.pdf https://doi.org/10.1029/2012GC004145 |
genre |
Kamchatka |
genre_facet |
Kamchatka |
op_source |
ISSN: 1525-2027 EISSN: 1525-2027 Geochemistry, Geophysics, Geosystems https://hal.science/hal-00793975 Geochemistry, Geophysics, Geosystems, 2012, 13 (1), pp.Q0AF05. ⟨10.1029/2012GC004145⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2012GC004145 hal-00793975 https://hal.science/hal-00793975 https://hal.science/hal-00793975/document https://hal.science/hal-00793975/file/Geochem%20Geophys%20Geosyst%20-%202012%20-%20B%20nard%20-%20A%20new%20petrogenetic%20model%20for%20low%25u2010Ca%20boninites%20Evidence%20from%20veined%20sub%25u2010arc.pdf doi:10.1029/2012GC004145 |
op_rights |
http://hal.archives-ouvertes.fr/licences/copyright/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1029/2012GC004145 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
13 |
container_issue |
6 |
container_start_page |
n/a |
op_container_end_page |
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1769007118331936768 |
spelling |
ftinsu:oai:HAL:hal-00793975v1 2023-06-18T03:41:30+02:00 A new petrogenetic model for low-Ca boninites: Evidence from veined sub-arc xenoliths on melt-mantle interaction and melt fractionation Bénard, A. Ionov, D. A. Laboratoire Magmas et Volcans (LMV) Observatoire de Physique du Globe de Clermont-Ferrand (OPGC) Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS) 2012 https://hal.science/hal-00793975 https://hal.science/hal-00793975/document https://hal.science/hal-00793975/file/Geochem%20Geophys%20Geosyst%20-%202012%20-%20B%20nard%20-%20A%20new%20petrogenetic%20model%20for%20low%25u2010Ca%20boninites%20Evidence%20from%20veined%20sub%25u2010arc.pdf https://doi.org/10.1029/2012GC004145 en eng HAL CCSD AGU and the Geochemical Society info:eu-repo/semantics/altIdentifier/doi/10.1029/2012GC004145 hal-00793975 https://hal.science/hal-00793975 https://hal.science/hal-00793975/document https://hal.science/hal-00793975/file/Geochem%20Geophys%20Geosyst%20-%202012%20-%20B%20nard%20-%20A%20new%20petrogenetic%20model%20for%20low%25u2010Ca%20boninites%20Evidence%20from%20veined%20sub%25u2010arc.pdf doi:10.1029/2012GC004145 http://hal.archives-ouvertes.fr/licences/copyright/ info:eu-repo/semantics/OpenAccess ISSN: 1525-2027 EISSN: 1525-2027 Geochemistry, Geophysics, Geosystems https://hal.science/hal-00793975 Geochemistry, Geophysics, Geosystems, 2012, 13 (1), pp.Q0AF05. ⟨10.1029/2012GC004145⟩ island arc low-Ca boninite mantle xenolith melt-rock interaction modeling [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDE.MCG]Environmental Sciences/Global Changes info:eu-repo/semantics/article Journal articles 2012 ftinsu https://doi.org/10.1029/2012GC004145 2023-06-05T21:02:53Z International audience Low-Ca boninites (LCB) are arc-related magmatic rocks enriched in large ion lithophile elements (LILE), light rare earth elements (LREE), Zr and Hf relative to medium to heavy REE (MREE-HREE). These signatures are commonly attributed to a unique slab-derived agent that metasomatized a depleted mantle source but their origin in such an agent remains enigmatic. We report andesite-hosted refractory spinel harzburgite xenoliths from the Kamchatka arc, which contain a series of orthopyroxene-rich veins; these veins range in thickness, the contents of clinopyroxene and amphibole and degrees of reaction with the host. Vein minerals in reaction zones with host harzburgites show progressive depletion in MREE-HREE at constant Zr-Hf and develop patterns (U-shaped REE with Zr-Hf spikes) that mimic those of LCB. Major and trace element modeling suggests that these veins (1) formed from a high-temperature (≥1400°C), MgO-rich (∼30 wt.%) and silicic (∼54 wt.% SiO2) initial melt, strongly depleted in Al2O3, TiO2and alkalis and (2) record fractionation of the initial melt to form hydrous liquids; the initial melt was equilibrated with metasomatized Kamchatka harzburgites and was similar in trace element abundances to island arc tholeiite (LREE-depleted to flat LREE-MREE patterns, low Nb and Ta but no significant Zr-Hf anomalies, high LILE). We argue that primary magmas of LCB formed by fluid-fluxed (LILE-rich and [Nb, Ta]-depleted fluid) melting of a cpx-free, highly refractory (≥30% melt extraction) harzburgitic source similar to arc peridotites from Kamchatka and elsewhere. This peculiar source may explain the distinctive major element features of LCB primary magmas. We propose that the primary magmas of LCB develop their characteristic trace element patterns through fractionation and reaction with refractory peridotites in the mantle wedge. Slab-related components alone may explain the high LILE in LCB but not their distinctive REE patterns and positive Zr-Hf anomalies. Article in Journal/Newspaper Kamchatka Institut national des sciences de l'Univers: HAL-INSU Geochemistry, Geophysics, Geosystems 13 6 n/a n/a |