Origin of the New Caledonian ophiolites based on a French-Australian seismic transect

The origin, age and nature of the New Caledonian ophiolites are still debated. Recently, as part of the joint French-Australian Seismic Transect (FAUST) program, the Australian research vessel Rig-Seismic recorded a series of multichannel deep-seismic profiles between the New Hebrides Are and the Australian margin. These profiles, which ran south of New Caledonia, image the southern prolongation of the overthrusted ophiolites and allow a new interpretation of the Eocene compressive tectonism along the New Caledonia-Norfolk Ridge. A model involving abduction of the whole oceanic lithosphere of the Loyalty Basin is consistent with the age and origin of the ophiolite. Variations in tectonic style along strike in the north-south-trending part of the Norfolk Ridge have produced ophiolite exposures related to uplifted and partially overthrust upper mantle slivers within the southern part of the Loyalty Basin. (C) 2000 Elsevier Science B.V. All rights reserved.