Canyon of Capbreton:: new morphostructural and morphosedimentary approaches.: First results of the ITSAS cruise

A recent cruise of the Suroit using new technologies for acquisition and processing of acoustic data (very high-resolution seismic and swath mapping) associated to an accurate satellite positioning, allowed producing a new bathymetric map of the upper part of the canyon. It shows the meandering shape of the canyon and superposed polyphase terrace. Such a morphology is due to activity of gravity flows that occurred as soon as the Upper Eocene. Very high-resolution seismic data allowed to confirm the influence of old tectonic structures on the location and the general shape of the canyon and to show that neotectonics that affects Plio-Quaternary deposits corresponds to recurrent activity of old tectonic structures. (C) 2001 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.