Résultats préliminaires du Leg 134 de l'Océan Drilling Program dans la zone de collision entre l'arc insulaire des Nouvelles-Hébrides et la Zone d'Entrecasteaux

Results of ODP Leg 134 indicate that the eastern d'Entrecasteaux zone (DEZ) is an immature intra-oceanic island arc along rvhich subduction ceased prior IO the Late Oligocene and that the DEZ emerged several times before the Late Pliocene or Early Pleistocene. The sedimentary cover of the North d'Entrecasteau.u Ridge (NDR), rvhich is part of the DEZ, is tectonically accreted at the toe of the inner wall of the New Hebrides trench arid undergoes severe dewatering. Within the accreted rocks fluids appear to concentrate along thrust zones. Directly east of the collision, the intra-arc North Aoba basin underwent a major tectonic event during the Late Pliocene or Early Pleistocene. During the Pleistocene, the axis of the basin migrated westward towards its present location. These events can be attributed to the DEZ-arc collision.