Évolution Temporelle et Spatiale du Système d'Interaction entre le point chaud de Tristan da Cunha et la Dorsale de l'Atlantique Sud.
In this work we have studied the space and time evolution of the Tristan hotspot and south Mid-Atlantic Ridge interaction system. The Tristan hotspot and its associated bathymetrical features (i.e. Walvis Ridge in the African plate and Rio Grande Rise in the South American plate) are ones of the mos...
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Other Authors: | , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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HAL CCSD
2011
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Subjects: | |
Online Access: | https://theses.hal.science/tel-00652905 https://theses.hal.science/tel-00652905/document https://theses.hal.science/tel-00652905/file/PESSANHA_ivo_2011_these-1.pdf |
id |
ftunivbrest:oai:HAL:tel-00652905v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Université de Bretagne Occidentale: HAL |
op_collection_id |
ftunivbrest |
language |
French |
topic |
hotspot mid-ocean ridge South Atlantic Walvis Ridge Rio Grande Rise geoid kinematics reconstructions axial jumps African plate South America plate plume flux isotopic ratio spherical harmonics point chaud Tristan da Cunha dorsale Atlantique Sud chaîne Walvis élévation du Rio Grande MBA RMBA géoïde reconstructions cinématiques sauts d'axes plaque africaine plaque sud-américaine flux de panache rapport isotopique harmoniques sphériques Gough et RSA [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDE.MCG]Environmental Sciences/Global Changes |
spellingShingle |
hotspot mid-ocean ridge South Atlantic Walvis Ridge Rio Grande Rise geoid kinematics reconstructions axial jumps African plate South America plate plume flux isotopic ratio spherical harmonics point chaud Tristan da Cunha dorsale Atlantique Sud chaîne Walvis élévation du Rio Grande MBA RMBA géoïde reconstructions cinématiques sauts d'axes plaque africaine plaque sud-américaine flux de panache rapport isotopique harmoniques sphériques Gough et RSA [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDE.MCG]Environmental Sciences/Global Changes Machado Pessanha, Ivo Bruno Évolution Temporelle et Spatiale du Système d'Interaction entre le point chaud de Tristan da Cunha et la Dorsale de l'Atlantique Sud. |
topic_facet |
hotspot mid-ocean ridge South Atlantic Walvis Ridge Rio Grande Rise geoid kinematics reconstructions axial jumps African plate South America plate plume flux isotopic ratio spherical harmonics point chaud Tristan da Cunha dorsale Atlantique Sud chaîne Walvis élévation du Rio Grande MBA RMBA géoïde reconstructions cinématiques sauts d'axes plaque africaine plaque sud-américaine flux de panache rapport isotopique harmoniques sphériques Gough et RSA [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDE.MCG]Environmental Sciences/Global Changes |
description |
In this work we have studied the space and time evolution of the Tristan hotspot and south Mid-Atlantic Ridge interaction system. The Tristan hotspot and its associated bathymetrical features (i.e. Walvis Ridge in the African plate and Rio Grande Rise in the South American plate) are ones of the most significant features of the South Atlantic Ocean. However, this system is not as well studied as the systems in the North Atlantic (e.g. Azores and Iceland), and their origin and evolution is an open subject. Data compilation of the available surveys from the National Geophysical Data Center (NGDC) and satellite-derived bathymetry were treated to generate a Digital Elevation Model (DEM) for the entire South Atlantic Ocean. Satellite-derived free-air anomaly data and sediment thickness data were used to calculate the mantle Bouguer anomaly (MBA) and digital isochrons of the ocean floor were used to calculate the residual mantle Bouguer anomaly (RMBA), residual bathymetry and new poles for the South America and Africa relative plate motions. Satellite-derived geoid data and the Earth Gravitational Model - EGM2008 were used for the separation of the different components in the geoid data with the calculation of filters using different levels and degree of spherical harmonics. From kinematic reconstructions based on new rotation poles calculated in this work and using the most accepted hypothesis for the current position of the hotspot, as the volcanic island of Tristan da Cunha, the chronology of the emplacement of the volcanic structures could be detailed. This highlighted the existence of several axes jumps and periodic variations in the magma supply to the axis resulting in a periodic alternation between periods of construction and axial ruptures of the axial plateau. The detailed comparison of the estimated position for the Tristan da Cunha hotspot and the location of the volcanic structures of the Walvis Ridge whose ages are known, underlined that the formation of the Walvis Ridge cannot be explained in its ... |
author2 |
Domaines Océaniques (LDO) Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS) Université de Bretagne occidentale - Brest Marcia Maia(marcia.maia@univ-brest.fr) |
format |
Doctoral or Postdoctoral Thesis |
author |
Machado Pessanha, Ivo Bruno |
author_facet |
Machado Pessanha, Ivo Bruno |
author_sort |
Machado Pessanha, Ivo Bruno |
title |
Évolution Temporelle et Spatiale du Système d'Interaction entre le point chaud de Tristan da Cunha et la Dorsale de l'Atlantique Sud. |
title_short |
Évolution Temporelle et Spatiale du Système d'Interaction entre le point chaud de Tristan da Cunha et la Dorsale de l'Atlantique Sud. |
title_full |
Évolution Temporelle et Spatiale du Système d'Interaction entre le point chaud de Tristan da Cunha et la Dorsale de l'Atlantique Sud. |
title_fullStr |
Évolution Temporelle et Spatiale du Système d'Interaction entre le point chaud de Tristan da Cunha et la Dorsale de l'Atlantique Sud. |
title_full_unstemmed |
Évolution Temporelle et Spatiale du Système d'Interaction entre le point chaud de Tristan da Cunha et la Dorsale de l'Atlantique Sud. |
title_sort |
évolution temporelle et spatiale du système d'interaction entre le point chaud de tristan da cunha et la dorsale de l'atlantique sud. |
publisher |
HAL CCSD |
publishDate |
2011 |
url |
https://theses.hal.science/tel-00652905 https://theses.hal.science/tel-00652905/document https://theses.hal.science/tel-00652905/file/PESSANHA_ivo_2011_these-1.pdf |
long_lat |
ENVELOPE(141.394,141.394,-66.820,-66.820) ENVELOPE(159.367,159.367,-81.633,-81.633) ENVELOPE(141.394,141.394,-66.820,-66.820) ENVELOPE(140.900,140.900,-66.735,-66.735) |
geographic |
Dorsale Gough La Dorsale Mid-Atlantic Ridge Tristan |
geographic_facet |
Dorsale Gough La Dorsale Mid-Atlantic Ridge Tristan |
genre |
Iceland North Atlantic South Atlantic Ocean |
genre_facet |
Iceland North Atlantic South Atlantic Ocean |
op_source |
https://theses.hal.science/tel-00652905 Géophysique [physics.geo-ph]. Université de Bretagne occidentale - Brest, 2011. Français. ⟨NNT : ⟩ |
op_relation |
tel-00652905 https://theses.hal.science/tel-00652905 https://theses.hal.science/tel-00652905/document https://theses.hal.science/tel-00652905/file/PESSANHA_ivo_2011_these-1.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1768390101178515456 |
spelling |
ftunivbrest:oai:HAL:tel-00652905v1 2023-06-11T04:13:17+02:00 Évolution Temporelle et Spatiale du Système d'Interaction entre le point chaud de Tristan da Cunha et la Dorsale de l'Atlantique Sud. Machado Pessanha, Ivo Bruno Domaines Océaniques (LDO) Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS) Université de Bretagne occidentale - Brest Marcia Maia(marcia.maia@univ-brest.fr) 2011-11-21 https://theses.hal.science/tel-00652905 https://theses.hal.science/tel-00652905/document https://theses.hal.science/tel-00652905/file/PESSANHA_ivo_2011_these-1.pdf fr fre HAL CCSD tel-00652905 https://theses.hal.science/tel-00652905 https://theses.hal.science/tel-00652905/document https://theses.hal.science/tel-00652905/file/PESSANHA_ivo_2011_these-1.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-00652905 Géophysique [physics.geo-ph]. Université de Bretagne occidentale - Brest, 2011. Français. ⟨NNT : ⟩ hotspot mid-ocean ridge South Atlantic Walvis Ridge Rio Grande Rise geoid kinematics reconstructions axial jumps African plate South America plate plume flux isotopic ratio spherical harmonics point chaud Tristan da Cunha dorsale Atlantique Sud chaîne Walvis élévation du Rio Grande MBA RMBA géoïde reconstructions cinématiques sauts d'axes plaque africaine plaque sud-américaine flux de panache rapport isotopique harmoniques sphériques Gough et RSA [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] [SDE.MCG]Environmental Sciences/Global Changes info:eu-repo/semantics/doctoralThesis Theses 2011 ftunivbrest 2023-05-02T22:36:11Z In this work we have studied the space and time evolution of the Tristan hotspot and south Mid-Atlantic Ridge interaction system. The Tristan hotspot and its associated bathymetrical features (i.e. Walvis Ridge in the African plate and Rio Grande Rise in the South American plate) are ones of the most significant features of the South Atlantic Ocean. However, this system is not as well studied as the systems in the North Atlantic (e.g. Azores and Iceland), and their origin and evolution is an open subject. Data compilation of the available surveys from the National Geophysical Data Center (NGDC) and satellite-derived bathymetry were treated to generate a Digital Elevation Model (DEM) for the entire South Atlantic Ocean. Satellite-derived free-air anomaly data and sediment thickness data were used to calculate the mantle Bouguer anomaly (MBA) and digital isochrons of the ocean floor were used to calculate the residual mantle Bouguer anomaly (RMBA), residual bathymetry and new poles for the South America and Africa relative plate motions. Satellite-derived geoid data and the Earth Gravitational Model - EGM2008 were used for the separation of the different components in the geoid data with the calculation of filters using different levels and degree of spherical harmonics. From kinematic reconstructions based on new rotation poles calculated in this work and using the most accepted hypothesis for the current position of the hotspot, as the volcanic island of Tristan da Cunha, the chronology of the emplacement of the volcanic structures could be detailed. This highlighted the existence of several axes jumps and periodic variations in the magma supply to the axis resulting in a periodic alternation between periods of construction and axial ruptures of the axial plateau. The detailed comparison of the estimated position for the Tristan da Cunha hotspot and the location of the volcanic structures of the Walvis Ridge whose ages are known, underlined that the formation of the Walvis Ridge cannot be explained in its ... Doctoral or Postdoctoral Thesis Iceland North Atlantic South Atlantic Ocean Université de Bretagne Occidentale: HAL Dorsale ENVELOPE(141.394,141.394,-66.820,-66.820) Gough ENVELOPE(159.367,159.367,-81.633,-81.633) La Dorsale ENVELOPE(141.394,141.394,-66.820,-66.820) Mid-Atlantic Ridge Tristan ENVELOPE(140.900,140.900,-66.735,-66.735) |