C ONCLUSIONS DE CE CHAPITRE

Dans ce chapitre, j’ai décrit les multiples processus pouvant intervenir dans la signature isotopique des OIB entre le moment de leur genèse lors de la fusion des panaches mantelliques et leur échantillonnage en surface. Ces interactions de faibles profondeurs peuvent être responsables d’une part non négligeable de la variabilité isotopique des OIB. Ces interactions sont multiples et peuvent intervenir à tous niveaux de la lithosphère océanique au sens large. En plus de cette variété de lieux, il faut noter aussi la grande diversité de composants avec lesquels les magmas peuvent interagir : lithosphère océanique métasomatisée, lithosphère sous-continentale détachée, croûte océanique et eau de mer. De plus, le simple effet de genèse des basaltes par fusion peut mener à une mauvaise identification des composants à l’origine des interactions.

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