Over a period of several years, various geophysical and geological studies have been performed on the Ligurian Sea margins in order to better understand the geodynamic processes of the region. These processes led firstly to the opening of the Ligurian Sea, and the separation of the Corsica-Sardinia microplate from the European plate during the lower Miocene, and secondly to the opening of the Northern Tyrrhenian Sea, which was initiated in the Upper Miocene.

In order to complete this work, more detailed studies are now being performed on the South Corsican-North Sardinian shelf. The result of these studies will be to reconstruct the evolution of the Corsican margins, and  to relate the submarine structures and evolution to the land geology.

Precise knowledge of the sea-floor morphology of the shelf has been obtained through processing  data from numerous detailed hydrographic surveys carried out by the French Hydrographic Office (SHOM). These data, completed by seismic reflection data acquired during 1999, have led to new , precise imaging of the structures of the Bonifacio shelves and their  contrasting morphologies. The Western shelf of Bonifacio Straits on one side is characterised by an Upper Miocene to Quaternary palaeomorphology (plateaus and palaeovalleys) where Lower to Upper Miocene series are still largely outcropping; whereas on the Eastern shelf, a thick Pliocene prograding sequence has doubled the width of the shelf, which is covered by a rather thin but continuous Quaternary sequence.

The Bocca 2000 cruise (7-16 October 2000) which is being conducted on the INSU ship Tethys II, is devoted to the acquisition of  additional seismic reflection profiles that aims to complete the investigation of the Bonifacio Miocene basin structure and its complex vertical evolution. These studies are conducted through co-operation between various laboratories and organisations: University of Corsica (Corte), BRGM, University of Brest, and the University of Cagliari which also performs sedimentological and geological studies. By combining these results, a new common mapping of the South Corsica-Sardinia land and sea areas will be achieved.

For further information please contact :
Pol Guennoc, Bureau de Recherche Géologique et Minière, France. p.guennoc@brgm.fr