Transect sismique continu entre l'arc des Nouvelles-Hébrides et la marge orientale de l'Australie: programme FAUST (French Australian Seismic Transect)

Abstract

Within the framework of the joint FAUST (French Australian Seismic: Transect) program, the Australian research vessel Rig-Seismic recorded a series of multichannel seismic profiles between the New Hebrides Arc and the Australian Margin. The very high quality of these profiles allows the examination of the continental or oceanic basement over the whole area surveyed. In basins beneath the eastern margin of the northern Lord Howe Rise and the New Caledonia Basin, where the crust is thinner, the Moho discontinuity is present at about 8.5 seconds two-way time (TWT) (about 12–13 km) on the profiles processed onboard. The data collected suggest that the sedimentary section within the basins includes syn-rift Cretaceous sediments that are not yet definitively identified. The Upper Eocene-Middle Oligocene subduction of the Australian plate beneath the Pacific plate is highlighted by thrust faults concentrated along the Lord Howe, Norfolk and Fairway Ridges. This episode probably corresponds to the period of convergent tectonism associated with the Upper Eocene obduction of the New Caledonian ophiolites.