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The interaction of the Mid-Atlantic Ridge with the North Atlantic Mantle Plume has produced a magmatic plateau centred about Iceland. The crust of this plateau is 30 km thick on average. This abnormal thickness implies that, unlike other slow-spreading ridges, addition of magmatic material to the cr...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.551.8410 2023-05-15T16:45:50+02:00 b Olivier Bourgeois Olivier Dauteuil Erwan Hallot The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.551.8410 http://www.mantleplumes.org/WebDocuments/Bourgeois2005.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.551.8410 http://www.mantleplumes.org/WebDocuments/Bourgeois2005.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.mantleplumes.org/WebDocuments/Bourgeois2005.pdf text ftciteseerx 2016-01-08T11:35:52Z The interaction of the Mid-Atlantic Ridge with the North Atlantic Mantle Plume has produced a magmatic plateau centred about Iceland. The crust of this plateau is 30 km thick on average. This abnormal thickness implies that, unlike other slow-spreading ridges, addition of magmatic material to the crust is not balanced by crustal stretching. The thermal effect of the plume also reduces the strength of the lithosphere. Both mechanisms affect the rifting process in Iceland. A structural review, including new field observa-tions, demonstrates that the structure of the Iceland plateau differs from that of other slow-spreading oceanic ridges. Lithospheric spreading is currently accommodated in a 200 km wide deformation strip, by the development of a system of half-grabens controlled by growth faults. Similar extinct structures, with various polarities, are preserved in the lava pile of the Iceland plateau. These struc-tures are identified as lithospheric rollover anticlines that developed in hanging walls of listric faults. We introduce a new tectonic model of accretion, whereby the development of the magmatic plateau involved activation, growth and decay of a system of growth fault/rollover systems underlain by shallow magma chambers. Deactivation of a given extensional system, after a lifetime of a few My, was at the expense of the activation of a new, laterally offset, one. Correspondingly, such systems formed successively at differ-ent places within a 200 km wide diffuse plate boundary. Unlike previous ones, this new model explains the lack of an axial valley in Iceland, the dip pattern of the lava pile, the complex geographical distribution of ages of extinct volcanic systems and the outcrops of extinct magma chambers. Text Iceland North Atlantic Unknown Iceland Plateau ENVELOPE(-12.000,-12.000,69.500,69.500) Mid-Atlantic Ridge |
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English |
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The interaction of the Mid-Atlantic Ridge with the North Atlantic Mantle Plume has produced a magmatic plateau centred about Iceland. The crust of this plateau is 30 km thick on average. This abnormal thickness implies that, unlike other slow-spreading ridges, addition of magmatic material to the crust is not balanced by crustal stretching. The thermal effect of the plume also reduces the strength of the lithosphere. Both mechanisms affect the rifting process in Iceland. A structural review, including new field observa-tions, demonstrates that the structure of the Iceland plateau differs from that of other slow-spreading oceanic ridges. Lithospheric spreading is currently accommodated in a 200 km wide deformation strip, by the development of a system of half-grabens controlled by growth faults. Similar extinct structures, with various polarities, are preserved in the lava pile of the Iceland plateau. These struc-tures are identified as lithospheric rollover anticlines that developed in hanging walls of listric faults. We introduce a new tectonic model of accretion, whereby the development of the magmatic plateau involved activation, growth and decay of a system of growth fault/rollover systems underlain by shallow magma chambers. Deactivation of a given extensional system, after a lifetime of a few My, was at the expense of the activation of a new, laterally offset, one. Correspondingly, such systems formed successively at differ-ent places within a 200 km wide diffuse plate boundary. Unlike previous ones, this new model explains the lack of an axial valley in Iceland, the dip pattern of the lava pile, the complex geographical distribution of ages of extinct volcanic systems and the outcrops of extinct magma chambers. |
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The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Olivier Bourgeois Olivier Dauteuil Erwan Hallot |
spellingShingle |
Olivier Bourgeois Olivier Dauteuil Erwan Hallot b |
author_facet |
Olivier Bourgeois Olivier Dauteuil Erwan Hallot |
author_sort |
Olivier Bourgeois |
title |
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title_short |
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title_full |
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title_full_unstemmed |
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url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.551.8410 http://www.mantleplumes.org/WebDocuments/Bourgeois2005.pdf |
long_lat |
ENVELOPE(-12.000,-12.000,69.500,69.500) |
geographic |
Iceland Plateau Mid-Atlantic Ridge |
geographic_facet |
Iceland Plateau Mid-Atlantic Ridge |
genre |
Iceland North Atlantic |
genre_facet |
Iceland North Atlantic |
op_source |
http://www.mantleplumes.org/WebDocuments/Bourgeois2005.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.551.8410 http://www.mantleplumes.org/WebDocuments/Bourgeois2005.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766035988150222848 |