Contrasting stress fields on correlating margins of the South Atlantic
Autor(a) principal: | |
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Data de Publicação: | 2015 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1016/j.gr.2014.09.006 http://hdl.handle.net/11449/177477 |
Resumo: | The passiveness of passive continental margins across the globe is currently under debate since several studies have shown that these margins may experience a variety of stress states and undergo significant vertical movement post-breakup. Of special interest is the South Atlantic, because the bounding continents have very different recent geological histories, with Africa experiencing continental rifting whereas South America is influenced by subduction on the Pacific side. It is not clear to what extent the Atlantic continental margins are subject to the same stresses and vertical motions as the main continents. To address this problem, we performed a paleostress analysis of two originally adjacent areas, i.e. NW Namibia and SE/S Brazil. Both areas are covered by the ~ 133-Ma-old Paraná-Etendeka extrusives that were emplaced shortly before or during the onset of the Atlantic rifting. Thus, the volcanics serve as a time marker for syn- or post-rift deformation. Collected fault slip data in the volcanics reveal remarkable differences between the two correlating areas. NW Namibia was dominated by extension in ENE-WSW and SW-NE directions, and by minor strike-slip movement with NW-SE directed compression. SE/S Brazil was mostly affected by strike-slip faulting, with compression oriented E-W and SW-NE. Similar fault systems appear widespread across SE Brazil and may be the combined result of flexural margin bending and the Nazca plate subduction. The results of NW Namibia differ from known compressional stress tensors in western South Africa, post-dating 90 Ma. The south-western African continental margin may thus have experienced a spatially variable stress history. Our results show that the tectonic evolution of the continental margins of the South Atlantic is not passive and that both margins vary significantly in structural style and stress fields, indicating that variable plate boundary forces play a major role in margin evolution. |
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Contrasting stress fields on correlating margins of the South AtlanticBrazilNamibiaPaleostressPassive marginSouth AtlanticThe passiveness of passive continental margins across the globe is currently under debate since several studies have shown that these margins may experience a variety of stress states and undergo significant vertical movement post-breakup. Of special interest is the South Atlantic, because the bounding continents have very different recent geological histories, with Africa experiencing continental rifting whereas South America is influenced by subduction on the Pacific side. It is not clear to what extent the Atlantic continental margins are subject to the same stresses and vertical motions as the main continents. To address this problem, we performed a paleostress analysis of two originally adjacent areas, i.e. NW Namibia and SE/S Brazil. Both areas are covered by the ~ 133-Ma-old Paraná-Etendeka extrusives that were emplaced shortly before or during the onset of the Atlantic rifting. Thus, the volcanics serve as a time marker for syn- or post-rift deformation. Collected fault slip data in the volcanics reveal remarkable differences between the two correlating areas. NW Namibia was dominated by extension in ENE-WSW and SW-NE directions, and by minor strike-slip movement with NW-SE directed compression. SE/S Brazil was mostly affected by strike-slip faulting, with compression oriented E-W and SW-NE. Similar fault systems appear widespread across SE Brazil and may be the combined result of flexural margin bending and the Nazca plate subduction. The results of NW Namibia differ from known compressional stress tensors in western South Africa, post-dating 90 Ma. The south-western African continental margin may thus have experienced a spatially variable stress history. Our results show that the tectonic evolution of the continental margins of the South Atlantic is not passive and that both margins vary significantly in structural style and stress fields, indicating that variable plate boundary forces play a major role in margin evolution.Institut für Geowissenschaften, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher Weg 21School of Geographical and Earth Sciences, University of GlasgowInstituto de Geociencias e Ciencias Exatas, UNESPInstitute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234Instituto de Geociencias e Ciencias Exatas, UNESPInstitut für Geowissenschaften, Johannes Gutenberg-Universität MainzSchool of Geographical and Earth Sciences, University of GlasgowUniversidade Estadual Paulista (Unesp)Institute of Earth Sciences, University of HeidelbergSalomon, EricKoehn, DanielPasschier, CeesHackspacher, Peter Christian [UNESP]Glasmacher, Ulrich Anton2018-12-11T17:25:39Z2018-12-11T17:25:39Z2015-01-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article1152-1167application/pdfhttp://dx.doi.org/10.1016/j.gr.2014.09.006Gondwana Research, v. 28, n. 3, p. 1152-1167, 2015.1342-937Xhttp://hdl.handle.net/11449/17747710.1016/j.gr.2014.09.0062-s2.0-849407667582-s2.0-84940766758.pdf10401359359087340000-0003-2125-3050Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengGondwana Researchinfo:eu-repo/semantics/openAccess2023-10-23T06:10:01Zoai:repositorio.unesp.br:11449/177477Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462023-10-23T06:10:01Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Contrasting stress fields on correlating margins of the South Atlantic |
title |
Contrasting stress fields on correlating margins of the South Atlantic |
spellingShingle |
Contrasting stress fields on correlating margins of the South Atlantic Salomon, Eric Brazil Namibia Paleostress Passive margin South Atlantic |
title_short |
Contrasting stress fields on correlating margins of the South Atlantic |
title_full |
Contrasting stress fields on correlating margins of the South Atlantic |
title_fullStr |
Contrasting stress fields on correlating margins of the South Atlantic |
title_full_unstemmed |
Contrasting stress fields on correlating margins of the South Atlantic |
title_sort |
Contrasting stress fields on correlating margins of the South Atlantic |
author |
Salomon, Eric |
author_facet |
Salomon, Eric Koehn, Daniel Passchier, Cees Hackspacher, Peter Christian [UNESP] Glasmacher, Ulrich Anton |
author_role |
author |
author2 |
Koehn, Daniel Passchier, Cees Hackspacher, Peter Christian [UNESP] Glasmacher, Ulrich Anton |
author2_role |
author author author author |
dc.contributor.none.fl_str_mv |
Institut für Geowissenschaften, Johannes Gutenberg-Universität Mainz School of Geographical and Earth Sciences, University of Glasgow Universidade Estadual Paulista (Unesp) Institute of Earth Sciences, University of Heidelberg |
dc.contributor.author.fl_str_mv |
Salomon, Eric Koehn, Daniel Passchier, Cees Hackspacher, Peter Christian [UNESP] Glasmacher, Ulrich Anton |
dc.subject.por.fl_str_mv |
Brazil Namibia Paleostress Passive margin South Atlantic |
topic |
Brazil Namibia Paleostress Passive margin South Atlantic |
description |
The passiveness of passive continental margins across the globe is currently under debate since several studies have shown that these margins may experience a variety of stress states and undergo significant vertical movement post-breakup. Of special interest is the South Atlantic, because the bounding continents have very different recent geological histories, with Africa experiencing continental rifting whereas South America is influenced by subduction on the Pacific side. It is not clear to what extent the Atlantic continental margins are subject to the same stresses and vertical motions as the main continents. To address this problem, we performed a paleostress analysis of two originally adjacent areas, i.e. NW Namibia and SE/S Brazil. Both areas are covered by the ~ 133-Ma-old Paraná-Etendeka extrusives that were emplaced shortly before or during the onset of the Atlantic rifting. Thus, the volcanics serve as a time marker for syn- or post-rift deformation. Collected fault slip data in the volcanics reveal remarkable differences between the two correlating areas. NW Namibia was dominated by extension in ENE-WSW and SW-NE directions, and by minor strike-slip movement with NW-SE directed compression. SE/S Brazil was mostly affected by strike-slip faulting, with compression oriented E-W and SW-NE. Similar fault systems appear widespread across SE Brazil and may be the combined result of flexural margin bending and the Nazca plate subduction. The results of NW Namibia differ from known compressional stress tensors in western South Africa, post-dating 90 Ma. The south-western African continental margin may thus have experienced a spatially variable stress history. Our results show that the tectonic evolution of the continental margins of the South Atlantic is not passive and that both margins vary significantly in structural style and stress fields, indicating that variable plate boundary forces play a major role in margin evolution. |
publishDate |
2015 |
dc.date.none.fl_str_mv |
2015-01-01 2018-12-11T17:25:39Z 2018-12-11T17:25:39Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1016/j.gr.2014.09.006 Gondwana Research, v. 28, n. 3, p. 1152-1167, 2015. 1342-937X http://hdl.handle.net/11449/177477 10.1016/j.gr.2014.09.006 2-s2.0-84940766758 2-s2.0-84940766758.pdf 1040135935908734 0000-0003-2125-3050 |
url |
http://dx.doi.org/10.1016/j.gr.2014.09.006 http://hdl.handle.net/11449/177477 |
identifier_str_mv |
Gondwana Research, v. 28, n. 3, p. 1152-1167, 2015. 1342-937X 10.1016/j.gr.2014.09.006 2-s2.0-84940766758 2-s2.0-84940766758.pdf 1040135935908734 0000-0003-2125-3050 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
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Gondwana Research |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
1152-1167 application/pdf |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
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Repositório Institucional da UNESP |
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Repositório Institucional da UNESP |
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Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
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