Propagation en contexte arrière-arc : premiers résultats de la campagne ProFeTi (Bassin Nord-Fidjien, Pacifique SW)

Sampling was conducted as part of the ProFeTi cruise of RV Alis in the middle of the North Fiji Basin along the NS spreading segment, which has been propagating northward inside the N15 segment for at least 1 Ma. Despite its back-arc geodynamic position, no geochemical signature of a subduction zone is noticeable. The studied sample set shows that the magma reservoir of this propagating segment evolves towards a thermal and geochemical equilibrium, which is disturbed by the following processes: 1) the influence of the remoteness of the propagator tip from the magmatic feed zones focused under the segment centre, 2) the periodic input of early magmas evolving as the propagator matures, and 3) the cold-edge effect of the N15 crust into which the NS segment propagates.