Shear-wave splitting beneath the Galápagos archipelago

Abstract : Shear-wave splitting measurements in the Galápagos archipelago show a rapid change from consistently oriented anisotropy to no measurable anisotropy. At the western edge of the archipelago delay times are 0.4– 0.9 s and fast polarization directions are 81– 109°E. These directions are consistent with anisotropy resulting from shear of the asthenosphere by the overlying plate; there is no indication of fossil lithospheric anisotropy in the plate spreading direction. In contrast, beneath the center of the archipelago the upper mantle is isotropic or weakly anisotropic. The isotropic region coincides approximately with a volume of anomalously low upper mantle velocities, suggesting that the presence of melt may weaken the effects of fabric on anisotropy or that melt preferred orientation generates a vertical fast polarization direction. Alternatively, the complex flow field associated with a near-ridge hotspot may result in apparent isotropy.
Type de document :
Article dans une revue
Geophysical Research Letters, American Geophysical Union, 2005, 32, 〈10.1029/2005GL024014〉
Liste complète des métadonnées

Littérature citée [21 références]  Voir  Masquer  Télécharger

http://hal.univ-reunion.fr/hal-01249089
Contributeur : Fabrice Fontaine <>
Soumis le : jeudi 31 décembre 2015 - 07:10:51
Dernière modification le : mardi 29 mai 2018 - 12:50:15
Document(s) archivé(s) le : mardi 5 avril 2016 - 13:46:04

Fichier

GRL2005.pdf
Fichiers éditeurs autorisés sur une archive ouverte

Identifiants

Collections

Citation

Fabrice R. Fontaine, Emilie Hooft, Peter Burkett, Douglas Toomey, Sean C. Solomon, et al.. Shear-wave splitting beneath the Galápagos archipelago. Geophysical Research Letters, American Geophysical Union, 2005, 32, 〈10.1029/2005GL024014〉. 〈hal-01249089〉

Partager

Métriques

Consultations de la notice

456

Téléchargements de fichiers

185