Géochimie isotopique du lithium dans les basaltes-Géochimie des ...

tel-00344949, version 1 - 7 Dec 2008
Analytical techniques
Major and trace elements:
Supplementary Materials
2. Article soumis à EPSL
Major element analyses were performed by ICP‐AES at Centre de Recherches
Pétrographiques et Géochimiques, Nancy following the method described in Carignan et al.
�2001�. The relative standard deviations are less than 2%. Trace element analyses were
performed by ICP‐MS at Grenoble using the method described in Barrat et al. �2000�. Based
on standard measurements and sample duplicates trace element concentrations
reproducibility
is generally better than 5%.
Sr, N d and Pb measurements: Sr measurements.
Isotopic compositions of Sr were determined at Géosciences Rennes. For Sr, rock
powders were leached for 3 hours in hot �150°C� 6N HCl, and rinsed in deionized water
prior to dissolution. Conventional ion exchange techniques were used for separation of Sr
and isotope ratio measurements were carried out by thermal ionization mass spectrometry
using a Finnigan Mat 262 equipped with 7 collectors. Isotopic ratios were normalized for
instrumental mass fractionation relative to 86 Sr/ 88 Sr � 0.1194. 87 Sr/ 86 Sr of the NBS 987 Sr
standard yielded 0.710213�22 �2 σ, n�14� and the sample Sr isotopic compositions are
eported relative to 87Sr/ 86 r
Sr � 0.71024.
Nd measurements.
Isotopic compositions of Nd were measured at Institut Universitaire Européen de la Mer,
Brest using a Thermo Finnigan, Triton. The Nd purification was done according to the
procedure described in Dosso et al. �1993�. TRU.Spec chromatographic resins from
Eichrom were used to separate the REE fraction from the sample matrix. Then, the
separation and elution of Nd and other REE were realized on Ln.Spec. resin. During the
course of the study, analyses of the La Jolla standard were performed and give an average
of 143 Nd/ 144 Nd � 0.511845�6 �n � 15�. All Nd data are fractionation corrected to
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