The South Moroccan margin and the first phases of Central Atlantic opening
We here propose a twofold approach to study the continental margins of the Central Atlantic Ocean, with special focus on the South Morocco Margin, in front of Reguibat bloc. This approach is based on plate kinematics reconstructions and geological field studies to map and constrain the geometry of t...
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2007
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ftunivnantes:oai:HAL:tel-00266944v1 2023-05-15T17:37:08+02:00 The South Moroccan margin and the first phases of Central Atlantic opening La marge sud-marocaine et les premières phases d'ouverture de l'océan Atlantique Central Labails, Cinthia 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 Jean-Louis Olivet(jl.olivet@gmail.com) 2007-03-05 https://theses.hal.science/tel-00266944 https://theses.hal.science/tel-00266944/document https://theses.hal.science/tel-00266944/file/figures-vol2.pdf https://theses.hal.science/tel-00266944/file/texte-vol1.pdf fr fre HAL CCSD tel-00266944 https://theses.hal.science/tel-00266944 https://theses.hal.science/tel-00266944/document https://theses.hal.science/tel-00266944/file/figures-vol2.pdf https://theses.hal.science/tel-00266944/file/texte-vol1.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-00266944 Géologie appliquée. Université de Bretagne occidentale - Brest, 2007. Français. ⟨NNT : ⟩ South Moroccan margin combined wide-angle and deep reflection seismic tectonic inheritance non-volcanic continental passive margin crustal structure marge continentale passive Sud Maroc structure crustale sismique réflexion et réfraction héritage tectonique [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology info:eu-repo/semantics/doctoralThesis Theses 2007 ftunivnantes 2023-02-08T06:25:15Z We here propose a twofold approach to study the continental margins of the Central Atlantic Ocean, with special focus on the South Morocco Margin, in front of Reguibat bloc. This approach is based on plate kinematics reconstructions and geological field studies to map and constrain the geometry of the plate boundary though time and seismic sections (reflection and refraction) to decipher the tectonic and sedimentary history of the margin. Sahabi et al. (2004) recently showed that the opening of the central Atlantic Ocean started 195 my ago (Sinemurian basis) (i.e. 20 my later than what was generally proposed in earlier models). Based on this result and on the analysis of geophysical data (including new seismic lines, a new magnetic anomaly grid and satellite derived gravimetry), our kinematic study evidences several tectonic phases: oceanic accretion started at an extremely slow rate (~0.8 cm/y) during about 30 my (Lias-Dogger). At ~165 my ago (Callovian basis), a change in the relative plate motions occurred, that resulted in a change in basement topography and an acceleration of spreading rate, up to ~ 4.8 cm/y. The BSMA (Blake Spur Magnetic Anomaly) is related to this change. From Magnetic Chron M22 (150 my, Tithonian basis) onwards, the spreading rate slowed down to about 2.6 cm/y until Magnetic Chron M0 (125 my, Barremian-Aptian). On geodynamic side, the Atlantic domain divides into two major domains: whereas Europe and the future North Atlantic, at Permo-Triassic times, know period of distension, central Atlantic Ocean stay in compression during the end of Permian (Alleghanian phase) et seems to register distension only at Triassic times. Margin segment, localized between Moroccan Meseta and Nova Scotia, characterized by a huge Triassic province of evaporates, occupies an intermediate position between these two domains. Besides to this segment clearly inherited of Hercynian orogeny, meridional domain is also segmented with a segmentation wavelength of about 600 km. An analysis in several regions worldwide ... Doctoral or Postdoctoral Thesis North Atlantic Université de Nantes: HAL-UNIV-NANTES |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
French |
topic |
South Moroccan margin combined wide-angle and deep reflection seismic tectonic inheritance non-volcanic continental passive margin crustal structure marge continentale passive Sud Maroc structure crustale sismique réflexion et réfraction héritage tectonique [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology |
spellingShingle |
South Moroccan margin combined wide-angle and deep reflection seismic tectonic inheritance non-volcanic continental passive margin crustal structure marge continentale passive Sud Maroc structure crustale sismique réflexion et réfraction héritage tectonique [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology Labails, Cinthia The South Moroccan margin and the first phases of Central Atlantic opening |
topic_facet |
South Moroccan margin combined wide-angle and deep reflection seismic tectonic inheritance non-volcanic continental passive margin crustal structure marge continentale passive Sud Maroc structure crustale sismique réflexion et réfraction héritage tectonique [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology |
description |
We here propose a twofold approach to study the continental margins of the Central Atlantic Ocean, with special focus on the South Morocco Margin, in front of Reguibat bloc. This approach is based on plate kinematics reconstructions and geological field studies to map and constrain the geometry of the plate boundary though time and seismic sections (reflection and refraction) to decipher the tectonic and sedimentary history of the margin. Sahabi et al. (2004) recently showed that the opening of the central Atlantic Ocean started 195 my ago (Sinemurian basis) (i.e. 20 my later than what was generally proposed in earlier models). Based on this result and on the analysis of geophysical data (including new seismic lines, a new magnetic anomaly grid and satellite derived gravimetry), our kinematic study evidences several tectonic phases: oceanic accretion started at an extremely slow rate (~0.8 cm/y) during about 30 my (Lias-Dogger). At ~165 my ago (Callovian basis), a change in the relative plate motions occurred, that resulted in a change in basement topography and an acceleration of spreading rate, up to ~ 4.8 cm/y. The BSMA (Blake Spur Magnetic Anomaly) is related to this change. From Magnetic Chron M22 (150 my, Tithonian basis) onwards, the spreading rate slowed down to about 2.6 cm/y until Magnetic Chron M0 (125 my, Barremian-Aptian). On geodynamic side, the Atlantic domain divides into two major domains: whereas Europe and the future North Atlantic, at Permo-Triassic times, know period of distension, central Atlantic Ocean stay in compression during the end of Permian (Alleghanian phase) et seems to register distension only at Triassic times. Margin segment, localized between Moroccan Meseta and Nova Scotia, characterized by a huge Triassic province of evaporates, occupies an intermediate position between these two domains. Besides to this segment clearly inherited of Hercynian orogeny, meridional domain is also segmented with a segmentation wavelength of about 600 km. An analysis in several regions worldwide ... |
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 Jean-Louis Olivet(jl.olivet@gmail.com) |
format |
Doctoral or Postdoctoral Thesis |
author |
Labails, Cinthia |
author_facet |
Labails, Cinthia |
author_sort |
Labails, Cinthia |
title |
The South Moroccan margin and the first phases of Central Atlantic opening |
title_short |
The South Moroccan margin and the first phases of Central Atlantic opening |
title_full |
The South Moroccan margin and the first phases of Central Atlantic opening |
title_fullStr |
The South Moroccan margin and the first phases of Central Atlantic opening |
title_full_unstemmed |
The South Moroccan margin and the first phases of Central Atlantic opening |
title_sort |
south moroccan margin and the first phases of central atlantic opening |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://theses.hal.science/tel-00266944 https://theses.hal.science/tel-00266944/document https://theses.hal.science/tel-00266944/file/figures-vol2.pdf https://theses.hal.science/tel-00266944/file/texte-vol1.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
https://theses.hal.science/tel-00266944 Géologie appliquée. Université de Bretagne occidentale - Brest, 2007. Français. ⟨NNT : ⟩ |
op_relation |
tel-00266944 https://theses.hal.science/tel-00266944 https://theses.hal.science/tel-00266944/document https://theses.hal.science/tel-00266944/file/figures-vol2.pdf https://theses.hal.science/tel-00266944/file/texte-vol1.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766136871099826176 |