Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean)
We report a survey carried out on basalt flows from Amsterdam Island in order to check the presence of intermediate directions interpreted to belong to a geomagnetic field excursion within the Brunhes epoch, completing this paleomagnetic record with paleointensity determinations and radiometric dati...
Published in: | Geophysical Journal International |
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Main Authors: | , , , , |
Other Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2003
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Subjects: | |
Online Access: | https://hal.archives-ouvertes.fr/hal-00000314 https://hal.archives-ouvertes.fr/hal-00000314v2/document https://hal.archives-ouvertes.fr/hal-00000314v2/file/GC102.pdf https://doi.org/10.1046/j.1365-246X.2003.01993.x |
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ftccsdartic:oai:HAL:hal-00000314v2 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
geomagnetic excursion paleointensity indian ocean Mono Lake Laschamp quaternary Amsterdam Island 40Ar/39Ar dating paleomagnetism geomagnetism [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] |
spellingShingle |
geomagnetic excursion paleointensity indian ocean Mono Lake Laschamp quaternary Amsterdam Island 40Ar/39Ar dating paleomagnetism geomagnetism [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] Carvallo, Claire Camps, Pierre Ruffet, Gilles Henry, Bernard Poidras, Thierry Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean) |
topic_facet |
geomagnetic excursion paleointensity indian ocean Mono Lake Laschamp quaternary Amsterdam Island 40Ar/39Ar dating paleomagnetism geomagnetism [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] |
description |
We report a survey carried out on basalt flows from Amsterdam Island in order to check the presence of intermediate directions interpreted to belong to a geomagnetic field excursion within the Brunhes epoch, completing this paleomagnetic record with paleointensity determinations and radiometric dating. The directional results corroborate the findings by Watkins and Nougier (1973) : normal polarity is found for two units and an intermediate direction, with associated VGPs close to the equator, for the other two units. A notable result is that these volcanic rocks are well suited for absolute paleointensity determinations. Fifty percent of the samples yields reliable intensity values with high quality factors. An original element of this study is that we made use of the PTRM-tail test of Shcherbakova et al. (2000) to help in the interpretation of the paleointensity measurements. Doing thus, only the high temperature intervals, beyond 400 degres C, were retained to obtain the most reliable estimate of the strength of the ancient magnetic field. The normal units yield Virtual Dipole Moments (VDM) of 6.2 and 7.7 10e22 Am2 and the excursional units yield values of 3.7 and 3.4 10e22 Am2. These results are quite consistent with the other Thellier determinations from Brunhes excursion records, all characterized by a decrease of the VDM as VGP latitude decreases. 40Ar/39Ar isotopic age determinations provide an estimate of 26+-15 Kyr and 18+-9 Kyr for the transitional lava flows, which could correspond to the Mono Lake excursion. However, the large error bars associated with these ages do not exclude the hypothesis that this event is the Laschamp. |
author2 |
Laboratoire de Tectonophysique (Tectonophysique) Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS) Géosciences Rennes (GR) Université de Rennes 1 (UR1) Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS) Laboratoire de Géomagnétisme et Paléomagnétisme (LGP) Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Carvallo, Claire Camps, Pierre Ruffet, Gilles Henry, Bernard Poidras, Thierry |
author_facet |
Carvallo, Claire Camps, Pierre Ruffet, Gilles Henry, Bernard Poidras, Thierry |
author_sort |
Carvallo, Claire |
title |
Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean) |
title_short |
Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean) |
title_full |
Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean) |
title_fullStr |
Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean) |
title_full_unstemmed |
Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean) |
title_sort |
mono lake or laschamp geomagnetic event recorded from lava flows in amsterdam island (southeastern indian ocean) |
publisher |
HAL CCSD |
publishDate |
2003 |
url |
https://hal.archives-ouvertes.fr/hal-00000314 https://hal.archives-ouvertes.fr/hal-00000314v2/document https://hal.archives-ouvertes.fr/hal-00000314v2/file/GC102.pdf https://doi.org/10.1046/j.1365-246X.2003.01993.x |
long_lat |
ENVELOPE(10.533,10.533,-71.833,-71.833) ENVELOPE(-67.086,-67.086,-66.354,-66.354) |
geographic |
Indian Shcherbakova Watkins |
geographic_facet |
Indian Shcherbakova Watkins |
genre |
Amsterdam Island |
genre_facet |
Amsterdam Island |
op_source |
ISSN: 0956-540X EISSN: 1365-246X Geophysical Journal International https://hal.archives-ouvertes.fr/hal-00000314 Geophysical Journal International, Oxford University Press (OUP), 2003, 154, pp.767-782. ⟨10.1046/j.1365-246X.2003.01993.x⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/arxiv/physics/0304061 info:eu-repo/semantics/altIdentifier/doi/10.1046/j.1365-246X.2003.01993.x hal-00000314 https://hal.archives-ouvertes.fr/hal-00000314 https://hal.archives-ouvertes.fr/hal-00000314v2/document https://hal.archives-ouvertes.fr/hal-00000314v2/file/GC102.pdf ARXIV: physics/0304061 doi:10.1046/j.1365-246X.2003.01993.x |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1046/j.1365-246X.2003.01993.x |
container_title |
Geophysical Journal International |
container_volume |
154 |
container_issue |
3 |
container_start_page |
767 |
op_container_end_page |
782 |
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1766364803535732736 |
spelling |
ftccsdartic:oai:HAL:hal-00000314v2 2023-05-15T13:22:25+02:00 Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean) Carvallo, Claire Camps, Pierre Ruffet, Gilles Henry, Bernard Poidras, Thierry Laboratoire de Tectonophysique (Tectonophysique) Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS) Géosciences Rennes (GR) Université de Rennes 1 (UR1) Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS) Laboratoire de Géomagnétisme et Paléomagnétisme (LGP) Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS) 2003 https://hal.archives-ouvertes.fr/hal-00000314 https://hal.archives-ouvertes.fr/hal-00000314v2/document https://hal.archives-ouvertes.fr/hal-00000314v2/file/GC102.pdf https://doi.org/10.1046/j.1365-246X.2003.01993.x en eng HAL CCSD Oxford University Press (OUP) info:eu-repo/semantics/altIdentifier/arxiv/physics/0304061 info:eu-repo/semantics/altIdentifier/doi/10.1046/j.1365-246X.2003.01993.x hal-00000314 https://hal.archives-ouvertes.fr/hal-00000314 https://hal.archives-ouvertes.fr/hal-00000314v2/document https://hal.archives-ouvertes.fr/hal-00000314v2/file/GC102.pdf ARXIV: physics/0304061 doi:10.1046/j.1365-246X.2003.01993.x info:eu-repo/semantics/OpenAccess ISSN: 0956-540X EISSN: 1365-246X Geophysical Journal International https://hal.archives-ouvertes.fr/hal-00000314 Geophysical Journal International, Oxford University Press (OUP), 2003, 154, pp.767-782. ⟨10.1046/j.1365-246X.2003.01993.x⟩ geomagnetic excursion paleointensity indian ocean Mono Lake Laschamp quaternary Amsterdam Island 40Ar/39Ar dating paleomagnetism geomagnetism [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] info:eu-repo/semantics/article Journal articles 2003 ftccsdartic https://doi.org/10.1046/j.1365-246X.2003.01993.x 2021-11-21T06:23:24Z We report a survey carried out on basalt flows from Amsterdam Island in order to check the presence of intermediate directions interpreted to belong to a geomagnetic field excursion within the Brunhes epoch, completing this paleomagnetic record with paleointensity determinations and radiometric dating. The directional results corroborate the findings by Watkins and Nougier (1973) : normal polarity is found for two units and an intermediate direction, with associated VGPs close to the equator, for the other two units. A notable result is that these volcanic rocks are well suited for absolute paleointensity determinations. Fifty percent of the samples yields reliable intensity values with high quality factors. An original element of this study is that we made use of the PTRM-tail test of Shcherbakova et al. (2000) to help in the interpretation of the paleointensity measurements. Doing thus, only the high temperature intervals, beyond 400 degres C, were retained to obtain the most reliable estimate of the strength of the ancient magnetic field. The normal units yield Virtual Dipole Moments (VDM) of 6.2 and 7.7 10e22 Am2 and the excursional units yield values of 3.7 and 3.4 10e22 Am2. These results are quite consistent with the other Thellier determinations from Brunhes excursion records, all characterized by a decrease of the VDM as VGP latitude decreases. 40Ar/39Ar isotopic age determinations provide an estimate of 26+-15 Kyr and 18+-9 Kyr for the transitional lava flows, which could correspond to the Mono Lake excursion. However, the large error bars associated with these ages do not exclude the hypothesis that this event is the Laschamp. Article in Journal/Newspaper Amsterdam Island Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Indian Shcherbakova ENVELOPE(10.533,10.533,-71.833,-71.833) Watkins ENVELOPE(-67.086,-67.086,-66.354,-66.354) Geophysical Journal International 154 3 767 782 |