High-resolution seismic and sequence stratigraphy of the Upper Jurassic deposits of the Boulonnais (northern France)

Very high-resolution seismic data were obtained from a Kimmeridnian-Tithoni an submarine series located off the Boulonnais (northern France). The data were compared with high-resolution sequence stratigraphic results obtained on the same formations cropping out on the adjacent coastal cliffs. The sei smic data provide better defined geometrical relationships between the sequ ences and the surfaces ('toplap','downlap') than the ones identified in the field. Based on the identification of downlap and toplap surfaces, one of the major contributions of the seismic data is to point out that the sandst one bodies isolated in offshore shales are sharp-based shoreface deposits i nduced by forced regression. ((C) Academie des sciences / Elsevier, Paris.) .