Lithium isotope composition of rocks and minerals as tracers for metamorphic processes within the lithosphere at MAR between 14° and 16° N (ODP Leg 209)

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We propose to investigate the d7Li isotope systematics of rocks drilled during ODP Leg 209. The project is focused on the evolution of conditions... of seawater-peridotite interactions because of the remarkable variability of serpentinization reactions and intensities of alteration observed in Leg 209 samples. These rocks provide a unique opportunity to gain new insights into the metamorphic transformation of the oceanic lithosphere, which is important for the rheology of the crust and key to understand geochemical mass cycles. The process of serpentinization will be studied using lithium isotopic composition of the different serpentinization styles. The composition of carbonate veins... will provide insights into late oxidative low temperature alteration processes. In order to study high temperature alteration of peridotite hosted gabbros we will determine d7Li values of amphiboles. All proposed subtopics are planned and will be investigated in close cooperation with scientist of the shipboard party.