Global equivalent magnetization of the oceanic lithosphere
International audience As a by-product of the construction of a new World Digital Magnetic Anomaly Map over oceanic areas, we use an original approach based on the global forward modeling of seafloor spreading magnetic anomalies and their comparison to the available marine magnetic data to derive th...
Published in: | Earth and Planetary Science Letters |
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Online Access: | https://insu.hal.science/insu-03579371 https://doi.org/10.1016/j.epsl.2015.08.002 |
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ftunivnantes:oai:HAL:insu-03579371v1 2023-11-12T04:06:34+01:00 Global equivalent magnetization of the oceanic lithosphere Dyment, J. Choi, Y. Hamoudi, M. Lesur, V. Thébault, Erwan 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 de Planétologie et Géodynamique UMR 6112 (LPG) Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST) Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) 2015 https://insu.hal.science/insu-03579371 https://doi.org/10.1016/j.epsl.2015.08.002 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2015.08.002 insu-03579371 https://insu.hal.science/insu-03579371 BIBCODE: 2015E&PSL.430.54D doi:10.1016/j.epsl.2015.08.002 ISSN: 0012-821X Earth and Planetary Science Letters https://insu.hal.science/insu-03579371 Earth and Planetary Science Letters, 2015, 430, pp.54-65. ⟨10.1016/j.epsl.2015.08.002⟩ marine magnetic anomalies magnetization oceanic lithosphere [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2015 ftunivnantes https://doi.org/10.1016/j.epsl.2015.08.002 2023-10-24T22:40:48Z International audience As a by-product of the construction of a new World Digital Magnetic Anomaly Map over oceanic areas, we use an original approach based on the global forward modeling of seafloor spreading magnetic anomalies and their comparison to the available marine magnetic data to derive the first map of the equivalent magnetization over the World's ocean. This map reveals consistent patterns related to the age of the oceanic lithosphere, the spreading rate at which it was formed, and the presence of mantle thermal anomalies which affects seafloor spreading and the resulting lithosphere. As for the age, the equivalent magnetization decreases significantly during the first 10-15 Myr after its formation, probably due to the alteration of crustal magnetic minerals under pervasive hydrothermal alteration, then increases regularly between 20 and 70 Ma, reflecting variations in the field strength or source effects such as the acquisition of a secondary magnetization. As for the spreading rate, the equivalent magnetization is twice as strong in areas formed at fast rate than in those formed at slow rate, with a threshold at ∼40 km/Myr, in agreement with an independent global analysis of the amplitude of Anomaly 25. This result, combined with those from the study of the anomalous skewness of marine magnetic anomalies, allows building a unified model for the magnetic structure of normal oceanic lithosphere as a function of spreading rate. Finally, specific areas affected by thermal mantle anomalies at the time of their formation exhibit peculiar equivalent magnetization signatures, such as the cold Australian-Antarctic Discordance, marked by a lower magnetization, and several hotspots, marked by a high magnetization. Article in Journal/Newspaper Antarc* Antarctic Université de Nantes: HAL-UNIV-NANTES Antarctic Australian-Antarctic Discordance ENVELOPE(124.000,124.000,-49.000,-49.000) Earth and Planetary Science Letters 430 54 65 |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
marine magnetic anomalies magnetization oceanic lithosphere [SDU]Sciences of the Universe [physics] |
spellingShingle |
marine magnetic anomalies magnetization oceanic lithosphere [SDU]Sciences of the Universe [physics] Dyment, J. Choi, Y. Hamoudi, M. Lesur, V. Thébault, Erwan Global equivalent magnetization of the oceanic lithosphere |
topic_facet |
marine magnetic anomalies magnetization oceanic lithosphere [SDU]Sciences of the Universe [physics] |
description |
International audience As a by-product of the construction of a new World Digital Magnetic Anomaly Map over oceanic areas, we use an original approach based on the global forward modeling of seafloor spreading magnetic anomalies and their comparison to the available marine magnetic data to derive the first map of the equivalent magnetization over the World's ocean. This map reveals consistent patterns related to the age of the oceanic lithosphere, the spreading rate at which it was formed, and the presence of mantle thermal anomalies which affects seafloor spreading and the resulting lithosphere. As for the age, the equivalent magnetization decreases significantly during the first 10-15 Myr after its formation, probably due to the alteration of crustal magnetic minerals under pervasive hydrothermal alteration, then increases regularly between 20 and 70 Ma, reflecting variations in the field strength or source effects such as the acquisition of a secondary magnetization. As for the spreading rate, the equivalent magnetization is twice as strong in areas formed at fast rate than in those formed at slow rate, with a threshold at ∼40 km/Myr, in agreement with an independent global analysis of the amplitude of Anomaly 25. This result, combined with those from the study of the anomalous skewness of marine magnetic anomalies, allows building a unified model for the magnetic structure of normal oceanic lithosphere as a function of spreading rate. Finally, specific areas affected by thermal mantle anomalies at the time of their formation exhibit peculiar equivalent magnetization signatures, such as the cold Australian-Antarctic Discordance, marked by a lower magnetization, and several hotspots, marked by a high magnetization. |
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 de Planétologie et Géodynamique UMR 6112 (LPG) Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST) Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Dyment, J. Choi, Y. Hamoudi, M. Lesur, V. Thébault, Erwan |
author_facet |
Dyment, J. Choi, Y. Hamoudi, M. Lesur, V. Thébault, Erwan |
author_sort |
Dyment, J. |
title |
Global equivalent magnetization of the oceanic lithosphere |
title_short |
Global equivalent magnetization of the oceanic lithosphere |
title_full |
Global equivalent magnetization of the oceanic lithosphere |
title_fullStr |
Global equivalent magnetization of the oceanic lithosphere |
title_full_unstemmed |
Global equivalent magnetization of the oceanic lithosphere |
title_sort |
global equivalent magnetization of the oceanic lithosphere |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://insu.hal.science/insu-03579371 https://doi.org/10.1016/j.epsl.2015.08.002 |
long_lat |
ENVELOPE(124.000,124.000,-49.000,-49.000) |
geographic |
Antarctic Australian-Antarctic Discordance |
geographic_facet |
Antarctic Australian-Antarctic Discordance |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
ISSN: 0012-821X Earth and Planetary Science Letters https://insu.hal.science/insu-03579371 Earth and Planetary Science Letters, 2015, 430, pp.54-65. ⟨10.1016/j.epsl.2015.08.002⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2015.08.002 insu-03579371 https://insu.hal.science/insu-03579371 BIBCODE: 2015E&PSL.430.54D doi:10.1016/j.epsl.2015.08.002 |
op_doi |
https://doi.org/10.1016/j.epsl.2015.08.002 |
container_title |
Earth and Planetary Science Letters |
container_volume |
430 |
container_start_page |
54 |
op_container_end_page |
65 |
_version_ |
1782327661390987264 |