M. Carpentier, C. Chauvel, and N. Mattielli (2008). "Pb-Nd isotopic constraints on sedimentary input into the Lesser Antilles Arc system." EARTH AND PLANETARY SCIENCE LETTERS 272:199-211.

Lesser Antilles lavas exhibit a large range of Pb-Nd isotopic compositions, which includes the most radiogenic Pb isotopic compositions known for intra-oceanic arcs. They are also characterized by a strong chemical zoning from north to south along the arc, with the highest Pb isotope ratios being found in the southern islands. We studied the geochemical characteristics of subducting sediments at different latitudes, in order to constrain a potential north-south chemical gradient in the sediments. We show that mixing of local depleted mantle with sediments subducting under the northern part of the arc could explain the northern island lava Pb-Nd isotopic compositions. In the south, subducting sediments display higher Pb isotopes, and mixing of local depleted mantle with these sediments satisfactory explains the very radiogenic Pb isotopic composition of lavas from the southern part of the Lesser Antilles arc. Using PetDB, we compiled data for Atlantic MORB to determine the Pb and Nd isotopic compositions of the local depleted mantle. When combined with our measurements on the subducting sediments, these data helped us to evaluate the sedimentary contribution in the Lesser Antilles magma genesis. - M. Carpentier

 

M. Carpentier, C. Chauvel, and N. Mattielli (2008). "Pb-Nd isotopic constraints on sedimentary input into the Lesser Antilles Arc system." EARTH AND PLANETARY SCIENCE LETTERS 272:199-211. doi:10.1016/j.epsl.2008.04.036



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