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Volcanic passive margins: another way to break up continents

Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features...

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Autores principales: Geoffroy, L., Burov, E. B., Werner, P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4595843/
https://www.ncbi.nlm.nih.gov/pubmed/26442807
http://dx.doi.org/10.1038/srep14828
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author Geoffroy, L.
Burov, E. B.
Werner, P.
author_facet Geoffroy, L.
Burov, E. B.
Werner, P.
author_sort Geoffroy, L.
collection PubMed
description Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle.
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spelling pubmed-45958432015-10-13 Volcanic passive margins: another way to break up continents Geoffroy, L. Burov, E. B. Werner, P. Sci Rep Article Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle. Nature Publishing Group 2015-10-07 /pmc/articles/PMC4595843/ /pubmed/26442807 http://dx.doi.org/10.1038/srep14828 Text en Copyright © 2015, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Geoffroy, L.
Burov, E. B.
Werner, P.
Volcanic passive margins: another way to break up continents
title Volcanic passive margins: another way to break up continents
title_full Volcanic passive margins: another way to break up continents
title_fullStr Volcanic passive margins: another way to break up continents
title_full_unstemmed Volcanic passive margins: another way to break up continents
title_short Volcanic passive margins: another way to break up continents
title_sort volcanic passive margins: another way to break up continents
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4595843/
https://www.ncbi.nlm.nih.gov/pubmed/26442807
http://dx.doi.org/10.1038/srep14828
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