Sr-Nd-Hf isotopes along the Pacific Antarctic Ridge from 41 to 53°S

International audience Major, trace element and Sr-Nd-Hf isotope data in basalts collected along the Pacific-Antarctic Ridge (PAR) axis between 53 and 41°S, far from any hotspot influence, reveal tight coherent geochemical variations within the depleted MORB mantle. All samples are located below the...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Hamelin, C., Dosso, Laure, Hanan, B., Barrat, Jean-Alix, Ondréas, Hélène
Other Authors: Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Geological Sciences, San Diego State University (SDSU), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2010
Subjects:
Online Access:https://hal-insu.archives-ouvertes.fr/insu-00563384
https://hal-insu.archives-ouvertes.fr/insu-00563384/document
https://hal-insu.archives-ouvertes.fr/insu-00563384/file/GRL-Hamelin-2010.pdf
https://doi.org/10.1029/2010GL042979
Description
Summary:International audience Major, trace element and Sr-Nd-Hf isotope data in basalts collected along the Pacific-Antarctic Ridge (PAR) axis between 53 and 41°S, far from any hotspot influence, reveal tight coherent geochemical variations within the depleted MORB mantle. All samples are located below the Pacific reference line defining two sub-oceanic mantle domains on each side of the Easter microplate. The data extend the PAR 66-53°S field towards more radiogenic Sr (0.70264), less radiogenic Nd (ɛ = 7.7) and Hf (ɛ = 11.4) values. The along ridge geochemical variability is closely related to the morphological segmentation of the ridge. Anomalous geochemical features are attributed to the atypical morphology of two segments due to the presence of off-axis magmatism. The first order ridge discontinuity defined by the Menard transform fault separates two slightly different mantle domains, each with its own history.