Géochimie isotopique du lithium dans les basaltes-Géochimie des ...
Géochimie isotopique du lithium dans les basaltes-Géochimie des ...
Géochimie isotopique du lithium dans les basaltes-Géochimie des ...
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tel-00344949, version 1 - 7 Dec 2008<br />
2. Article soumis à EPSL<br />
Figure 2.12 : AFC model for Li concentration and isotopic composition. Two<br />
calculations are shown, each one for extremes value of the Li distribution<br />
coefficient �see the text for more details�. Fractional crystallization without<br />
assimilation is unable to generate Li isotopic fractionation by more than 1 ‰<br />
�Tomascak et al., 1999�.<br />
Although a majority of major and trace element contents in meta‐sedimentary xenoliths<br />
are consistent with those in greywacke‐pelitic rocks, the high grade metamorphism has<br />
significantly modified their large ion lithophile element concentrations �e.g. Rb, Sr, Li�<br />
�Leyreloup et al., 1977�. These xenoliths display mineralogical characteristics which are<br />
typical for almost anhydrous granulite facies rocks �Downes and Leyreloup, 1986�.<br />
Therefore, it is likely that meta‐sediments have released significant amounts of water<br />
<strong>du</strong>ring their metamorphic evolution towards the granulite facies. Numerous studies have<br />
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