High-resolution record of the Upper Olduvai transition from Po Valley (Italy) sediments: support for dipolar transition geometry?
International audience A detailed record of the Upper Olduvai polarity transition, composed of > 100 transitional directions, has been obtainedfrom the Crostolo section in northern Italy. A careful examination of the rock magnetic properties of the sediments usingstandard paleomagnetic techniques...
Published in: | Physics of the Earth and Planetary Interiors |
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Online Access: | https://hal.archives-ouvertes.fr/hal-03583548 https://doi.org/10.1016/0031-9201(91)90138-8 |
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ftunivnantes:oai:HAL:hal-03583548v1 2023-05-15T16:19:40+02:00 High-resolution record of the Upper Olduvai transition from Po Valley (Italy) sediments: support for dipolar transition geometry? Tric, Emmanuel Laj, Carlo Jéhanno, Célestine Valet, Jean-Pierre Kissel, Catherine Mazaud, Alain Iaccarino, Silvia Centre des Faibles Radioactivités Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS) Università degli studi di Parma = University of Parma (UNIPR) 1991-01 https://hal.archives-ouvertes.fr/hal-03583548 https://doi.org/10.1016/0031-9201(91)90138-8 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/0031-9201(91)90138-8 hal-03583548 https://hal.archives-ouvertes.fr/hal-03583548 doi:10.1016/0031-9201(91)90138-8 ISSN: 0031-9201 EISSN: 0031-9201 Physics of the Earth and Planetary Interiors https://hal.archives-ouvertes.fr/hal-03583548 Physics of the Earth and Planetary Interiors, 1991, 65 (3-5), pp.319-336. ⟨10.1016/0031-9201(91)90138-8⟩ [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment info:eu-repo/semantics/article Journal articles 1991 ftunivnantes https://doi.org/10.1016/0031-9201(91)90138-8 2022-11-30T00:23:20Z International audience A detailed record of the Upper Olduvai polarity transition, composed of > 100 transitional directions, has been obtainedfrom the Crostolo section in northern Italy. A careful examination of the rock magnetic properties of the sediments usingstandard paleomagnetic techniques, thermomagnetic, scanning electron microscopy, microprobe, X-ray diffraction andMdssbauer analysis, shows that greigite is the main magnetic carrier of the remanence. The correlation of a shift in themagnetic record to a small-scale sedimentary feature observed in the section indicates that themagnetization was acquired atdeposition, or very shortly after. The virtual geomagnetic pole (VGP) path is largely confined along a great circle over Northand South America — 90° west of the site and consists ofthree stages: first, the VGP moves to southern mid-latitudes, then,after a period ofstandstill, it comes back to almost true north, and, finally, the south pole is reached in a third step. Althoughdifferent from a record from the southern Indian Ocean, this path is virtually identical to those obtained for the sametransition from North Pacific deep-sea cores, and partly coincides with a North Atlantic record, which suggests that a dipolarcomponent may be present in the transitional field during the Upper Olduvas reversal. A review of the recently obtainedrecords of various transitions shows that in more than two-thirds ofthe cases the VGP paths are similarly confined along ameridian over the Americas or antipodal to them, irrespective ofthe sampling site and ofthe sense of the transition. Althoughnot deterministic, this tendency suggests that a similar dipolar component might be present in the transitional fields of otherreversals of different ages. Article in Journal/Newspaper Geomagnetic Pole North Atlantic South pole Université de Nantes: HAL-UNIV-NANTES Indian Pacific South Pole Physics of the Earth and Planetary Interiors 65 3-5 319 336 |
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Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment Tric, Emmanuel Laj, Carlo Jéhanno, Célestine Valet, Jean-Pierre Kissel, Catherine Mazaud, Alain Iaccarino, Silvia High-resolution record of the Upper Olduvai transition from Po Valley (Italy) sediments: support for dipolar transition geometry? |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment |
description |
International audience A detailed record of the Upper Olduvai polarity transition, composed of > 100 transitional directions, has been obtainedfrom the Crostolo section in northern Italy. A careful examination of the rock magnetic properties of the sediments usingstandard paleomagnetic techniques, thermomagnetic, scanning electron microscopy, microprobe, X-ray diffraction andMdssbauer analysis, shows that greigite is the main magnetic carrier of the remanence. The correlation of a shift in themagnetic record to a small-scale sedimentary feature observed in the section indicates that themagnetization was acquired atdeposition, or very shortly after. The virtual geomagnetic pole (VGP) path is largely confined along a great circle over Northand South America — 90° west of the site and consists ofthree stages: first, the VGP moves to southern mid-latitudes, then,after a period ofstandstill, it comes back to almost true north, and, finally, the south pole is reached in a third step. Althoughdifferent from a record from the southern Indian Ocean, this path is virtually identical to those obtained for the sametransition from North Pacific deep-sea cores, and partly coincides with a North Atlantic record, which suggests that a dipolarcomponent may be present in the transitional field during the Upper Olduvas reversal. A review of the recently obtainedrecords of various transitions shows that in more than two-thirds ofthe cases the VGP paths are similarly confined along ameridian over the Americas or antipodal to them, irrespective ofthe sampling site and ofthe sense of the transition. Althoughnot deterministic, this tendency suggests that a similar dipolar component might be present in the transitional fields of otherreversals of different ages. |
author2 |
Centre des Faibles Radioactivités Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS) Università degli studi di Parma = University of Parma (UNIPR) |
format |
Article in Journal/Newspaper |
author |
Tric, Emmanuel Laj, Carlo Jéhanno, Célestine Valet, Jean-Pierre Kissel, Catherine Mazaud, Alain Iaccarino, Silvia |
author_facet |
Tric, Emmanuel Laj, Carlo Jéhanno, Célestine Valet, Jean-Pierre Kissel, Catherine Mazaud, Alain Iaccarino, Silvia |
author_sort |
Tric, Emmanuel |
title |
High-resolution record of the Upper Olduvai transition from Po Valley (Italy) sediments: support for dipolar transition geometry? |
title_short |
High-resolution record of the Upper Olduvai transition from Po Valley (Italy) sediments: support for dipolar transition geometry? |
title_full |
High-resolution record of the Upper Olduvai transition from Po Valley (Italy) sediments: support for dipolar transition geometry? |
title_fullStr |
High-resolution record of the Upper Olduvai transition from Po Valley (Italy) sediments: support for dipolar transition geometry? |
title_full_unstemmed |
High-resolution record of the Upper Olduvai transition from Po Valley (Italy) sediments: support for dipolar transition geometry? |
title_sort |
high-resolution record of the upper olduvai transition from po valley (italy) sediments: support for dipolar transition geometry? |
publisher |
HAL CCSD |
publishDate |
1991 |
url |
https://hal.archives-ouvertes.fr/hal-03583548 https://doi.org/10.1016/0031-9201(91)90138-8 |
geographic |
Indian Pacific South Pole |
geographic_facet |
Indian Pacific South Pole |
genre |
Geomagnetic Pole North Atlantic South pole |
genre_facet |
Geomagnetic Pole North Atlantic South pole |
op_source |
ISSN: 0031-9201 EISSN: 0031-9201 Physics of the Earth and Planetary Interiors https://hal.archives-ouvertes.fr/hal-03583548 Physics of the Earth and Planetary Interiors, 1991, 65 (3-5), pp.319-336. ⟨10.1016/0031-9201(91)90138-8⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/0031-9201(91)90138-8 hal-03583548 https://hal.archives-ouvertes.fr/hal-03583548 doi:10.1016/0031-9201(91)90138-8 |
op_doi |
https://doi.org/10.1016/0031-9201(91)90138-8 |
container_title |
Physics of the Earth and Planetary Interiors |
container_volume |
65 |
container_issue |
3-5 |
container_start_page |
319 |
op_container_end_page |
336 |
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1766006080342589440 |