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Maia, Marcia; Pessanha, Ivo; Courreges, Esther; Patriat, Martin; Gente, Pascal; Hemond, Christophe; Janin, Myriam; Johnson, Kevin; Roest, Walter; Royer, Jean-yves; Vatteville, Judith. |
The Amsterdam-Saint Paul plateau results from a 10 Myr interaction between the South East Indian Ridge and the Amsterdam-Saint Paul hot spot. During this period of time, the structure of the plateau changed as a consequence of changes in both the ridge-hot spot relative distance and in the strength of the hot spot source. The joint analysis of gravity-derived crust thickness and bathymetry reveals that the plateau started to form at similar to 10 Ma by an increase of the crustal production at the ridge axis, due to the nearby hot spot. This phase, which lasted 3-4 Myr, corresponds to a period of a strong hot spot source, maybe due to a high temperature or material flux, and decreasing ridge-hot spot distance. A second phase, between similar to 6 and... |
Tipo: Text |
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Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00047/15865/13284.pdf |
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Maia, Marcia; Sichel, Susanna; Briais, Anne; Brunelli, Daniele; Ligi, Marco; Ferreira, Nicolas; Campos, Thomas; Mougel, Berengere; Brehme, Isa; Hemond, Christophe; Motoki, Akihisa; Moura, Denise; Scalabrin, Carla; Pessanha, Ivo; Alves, Eliane; Ayres, Arthur; Oliveira, Pedro. |
Mantle exhumation at slow-spreading ridges is favoured by extensional tectonics through low-angle detachment faults1, 2, 3, 4, and, along transforms, by transtension due to changes in ridge/transform geometry5, 6. Less common, exhumation by compressive stresses has been proposed for the large-offset transforms of the equatorial Atlantic7, 8. Here we show, using high-resolution bathymetry, seismic and gravity data, that the northern transform fault of the St Paul system has been controlled by compressive deformation since ~10 million years ago. The long-lived transpression resulted from ridge overlap due to the propagation of the northern Mid-Atlantic Ridge segment into the transform domain, which induced the migration and segmentation of the transform... |
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Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00345/45603/49042.pdf |
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