Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean
International audience Mid-ocean ridge basalts (MORB) from the Arctic Ocean have been much less studied than those from the Indian, Atlantic, and Pacific due to the difficulty of access related to ice cover. In 2001 and 2004 the Arctic ridges (Gakkel Ridge and Lena Trough) were intensively sampled....
Published in: | Geochemistry, Geophysics, Geosystems |
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Format: | Article in Journal/Newspaper |
Language: | English |
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2010
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Online Access: | https://insu.hal.science/insu-03605322 https://insu.hal.science/insu-03605322/document https://insu.hal.science/insu-03605322/file/Geochem%20Geophys%20Geosyst%20-%202010%20-%20Nauret%20-%20Rare%20gases%20in%20lavas%20from%20the%20ultraslow%20spreading%20Lena%20Trough%20Arctic%20Ocean.pdf https://doi.org/10.1029/2010GC003027 |
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[SDU]Sciences of the Universe [physics] |
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[SDU]Sciences of the Universe [physics] Nauret, F. Moreira, Manuel Snow, J. E. Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean |
topic_facet |
[SDU]Sciences of the Universe [physics] |
description |
International audience Mid-ocean ridge basalts (MORB) from the Arctic Ocean have been much less studied than those from the Indian, Atlantic, and Pacific due to the difficulty of access related to ice cover. In 2001 and 2004 the Arctic ridges (Gakkel Ridge and Lena Trough) were intensively sampled. In this study we present the first helium, neon, and argon concentrations and isotopic ratios in a suite of samples from the ultraslow spreading Lena Trough (∼0.75 cm/yr effective full rate). Central Lena Trough (CLT) lavas display 4 He/ 3 He between 89,710 and 97,530 (R/Ra between 7.4 and 8.1), similar to the mean MORB ratio of 90,000 ± 10,000 (R/Ra = 8 ± 1). In a three neon isotope diagram, the samples fall on the MORB line, without showing any excess of nucleogenic 21 Ne. The 40 Ar/ 36 Ar ratios vary from 349 to 6964. CLT samples have a typical MORB He and Ne isotopic composition. Rare gases do not indicate any mantle heterogeneities or contribution of subcontinental lithospheric mantle, although this has been suggested previously on the basis of the Sr-Nd and Pb isotopic systems. Based on noble gas systematics, a DUPAL-like anomaly is not observed in the Arctic Ocean. We propose two possible models which reconcile the rare gases with these previous studies. The first is that the Lena Trough mantle has a marble cake structure with small-scale heterogeneities (<1 km), allowing rapid diffusion and homogenization of rare gases compared to elements such as Sr, Nd, and Pb. The second model proposes that the recycled component identified by other isotopic systems was fully degassed at a recent date. It would therefore have a negligible mass budget of rare gases compared to other isotopic systems. This would suggest that the mantle enrichment beneath Lena Trough was generated by rift-forming processes and not by recycling. |
author2 |
Institut de Physique du Globe de Paris (IPGP) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS) 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 |
Nauret, F. Moreira, Manuel Snow, J. E. |
author_facet |
Nauret, F. Moreira, Manuel Snow, J. E. |
author_sort |
Nauret, F. |
title |
Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean |
title_short |
Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean |
title_full |
Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean |
title_fullStr |
Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean |
title_full_unstemmed |
Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean |
title_sort |
rare gases in lavas from the ultraslow spreading lena trough, arctic ocean |
publisher |
HAL CCSD |
publishDate |
2010 |
url |
https://insu.hal.science/insu-03605322 https://insu.hal.science/insu-03605322/document https://insu.hal.science/insu-03605322/file/Geochem%20Geophys%20Geosyst%20-%202010%20-%20Nauret%20-%20Rare%20gases%20in%20lavas%20from%20the%20ultraslow%20spreading%20Lena%20Trough%20Arctic%20Ocean.pdf https://doi.org/10.1029/2010GC003027 |
genre |
Arctic Arctic Ocean |
genre_facet |
Arctic Arctic Ocean |
op_source |
ISSN: 1525-2027 EISSN: 1525-2027 Geochemistry, Geophysics, Geosystems https://insu.hal.science/insu-03605322 Geochemistry, Geophysics, Geosystems, 2010, 11, ⟨10.1029/2010GC003027⟩ |
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http://hal.archives-ouvertes.fr/licences/copyright/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1029/2010GC003027 |
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Geochemistry, Geophysics, Geosystems |
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6 |
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ftccsdartic:oai:HAL:insu-03605322v1 2023-10-29T02:33:58+01:00 Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean Nauret, F. Moreira, Manuel Snow, J. E. Institut de Physique du Globe de Paris (IPGP) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS) 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) 2010 https://insu.hal.science/insu-03605322 https://insu.hal.science/insu-03605322/document https://insu.hal.science/insu-03605322/file/Geochem%20Geophys%20Geosyst%20-%202010%20-%20Nauret%20-%20Rare%20gases%20in%20lavas%20from%20the%20ultraslow%20spreading%20Lena%20Trough%20Arctic%20Ocean.pdf https://doi.org/10.1029/2010GC003027 en eng HAL CCSD AGU and the Geochemical Society info:eu-repo/semantics/altIdentifier/doi/10.1029/2010GC003027 insu-03605322 https://insu.hal.science/insu-03605322 https://insu.hal.science/insu-03605322/document https://insu.hal.science/insu-03605322/file/Geochem%20Geophys%20Geosyst%20-%202010%20-%20Nauret%20-%20Rare%20gases%20in%20lavas%20from%20the%20ultraslow%20spreading%20Lena%20Trough%20Arctic%20Ocean.pdf BIBCODE: 2010GGG.11.AC04N doi:10.1029/2010GC003027 http://hal.archives-ouvertes.fr/licences/copyright/ info:eu-repo/semantics/OpenAccess ISSN: 1525-2027 EISSN: 1525-2027 Geochemistry, Geophysics, Geosystems https://insu.hal.science/insu-03605322 Geochemistry, Geophysics, Geosystems, 2010, 11, ⟨10.1029/2010GC003027⟩ [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2010 ftccsdartic https://doi.org/10.1029/2010GC003027 2023-09-30T22:34:57Z International audience Mid-ocean ridge basalts (MORB) from the Arctic Ocean have been much less studied than those from the Indian, Atlantic, and Pacific due to the difficulty of access related to ice cover. In 2001 and 2004 the Arctic ridges (Gakkel Ridge and Lena Trough) were intensively sampled. In this study we present the first helium, neon, and argon concentrations and isotopic ratios in a suite of samples from the ultraslow spreading Lena Trough (∼0.75 cm/yr effective full rate). Central Lena Trough (CLT) lavas display 4 He/ 3 He between 89,710 and 97,530 (R/Ra between 7.4 and 8.1), similar to the mean MORB ratio of 90,000 ± 10,000 (R/Ra = 8 ± 1). In a three neon isotope diagram, the samples fall on the MORB line, without showing any excess of nucleogenic 21 Ne. The 40 Ar/ 36 Ar ratios vary from 349 to 6964. CLT samples have a typical MORB He and Ne isotopic composition. Rare gases do not indicate any mantle heterogeneities or contribution of subcontinental lithospheric mantle, although this has been suggested previously on the basis of the Sr-Nd and Pb isotopic systems. Based on noble gas systematics, a DUPAL-like anomaly is not observed in the Arctic Ocean. We propose two possible models which reconcile the rare gases with these previous studies. The first is that the Lena Trough mantle has a marble cake structure with small-scale heterogeneities (<1 km), allowing rapid diffusion and homogenization of rare gases compared to elements such as Sr, Nd, and Pb. The second model proposes that the recycled component identified by other isotopic systems was fully degassed at a recent date. It would therefore have a negligible mass budget of rare gases compared to other isotopic systems. This would suggest that the mantle enrichment beneath Lena Trough was generated by rift-forming processes and not by recycling. Article in Journal/Newspaper Arctic Arctic Ocean Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Geochemistry, Geophysics, Geosystems 11 6 n/a n/a |