Mesozoic diapirs at the eastern edge of Lord Howe Rise (southwest Pacific):: ZoNeCo 5 cruise.

The objective of the ZoNeCo 5 cruise on R/V L'Atalante was the bathy-metrical and geological survey of the eastern edge of the Lord Howe Rise, a key structure between New Caledonia and the eastern margin of Australia. The acquired data better defines the relationships between the New Caledonia Basin and the Lord Howe Rise in an area which is the southern prolongation of the Fairway basin. This basin contains a thick sedimentary sequence ranging from Lower Cretaceous to the present day. This basin extends on more than 70 000 km(2). The main result of the cruise was the discovery of a Pre-Cretaceous or Cretaceous series including salt or mud diapirs. At about 600 m below the sea floor and coincident with the distribution of diapirs, an extensive BSR (Bottom Simulating Reflector) suggests the existence of a large gas hydrates deposit. (C) 2000 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.