Helium isotopes on the Pacific-Antarctic ridge (52.5°–41.5°S)

International audience The first isotopic data and concentrations of helium are reported for the Pacific-Antarctic ridge between 52.5°S and 41.5°S. The 4He/3He ratio is extremely homogeneous over more than 1200 km, with a mean ratio of 99,275 (R/Ra = 7.29) and a standard deviation of 2719 (0.19), wh...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Moreira Manuel, A., Dosso, Laure, Ondréas, Hélène
Other Authors: Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), 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), Unité Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2008
Subjects:
helium isotopes
mantle geochemistry
Pacific-Antarctic ridge
[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry
[SDE.MCG]Environmental Sciences/Global Changes
Antarc*
Antarctic
Online Access:https://insu.hal.science/insu-00305185
https://insu.hal.science/insu-00305185/document
https://insu.hal.science/insu-00305185/file/GRL-Moreira-2008.pdf
https://doi.org/10.1029/2008GL033286
Description
Summary:International audience The first isotopic data and concentrations of helium are reported for the Pacific-Antarctic ridge between 52.5°S and 41.5°S. The 4He/3He ratio is extremely homogeneous over more than 1200 km, with a mean ratio of 99,275 (R/Ra = 7.29) and a standard deviation of 2719 (0.19), which is the lowest dispersion observed for the global mid oceanic ridge system. Moreover, the Menard T.F. is a frontier between two mantles with slightly different helium isotopic ratios (96,595 ± 1520 and 100,347 ± 2330). No difference in the helium concentration between the two ridge segments defined by the Menard T.F. can be observed, as well as no significant difference in the U and Th contents suggesting that the difference in helium isotopic ratio is old (>500 My) and may represent a slight difference in degassing or/and trace element depletion history

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