On the Kimmeridgian (Jurassic) succession of the Normandy coast, northern France

• Published in: Proceedings of the Geologists' Association 2005, Vol.116 (1), p.33-43
• Main Author: Gallois, R.W.
• Format: Article
• Language: English
• Subjects: Dorset; Kimmeridge Clay; Kimmeridgian Stage; Normandy; stratigraphy
• ISSN: 0016-7878
• DOI: 10.1016/S0016-7878(05)80015-X

Kimmeridgian rocks crop out on the Normandy coast north and south of the Seine Estuary at Le Havre in a series of small foreshore and cliff exposures separated by beach deposits and landslips. A total thickness of about 45 m of richly fossiliferous strata is exposed, ranging from the base of the Baylei Zone to the middle part of the Eudoxus Zone. The sections are mostly unprotected by sea-defence works and are subject to rapid marine erosion and renewal. Taken together, the Normandy exposures currently provide a more complete section through the low and middle parts of the Kimmeridgian Stage than any natural English section, including those of the Dorset type area. Descriptions and a stratigraphical interpretation of the Normandy sections are presented that enable the faunal collections to be placed in their regional chronostratigraphical context. The Kimmeridgian succession at outcrop on the Normandy coast contains numerous sedimentary breaks marked by erosion, hardground and omission surfaces. Some of these are disconformities that give rise to rapid lateral variations in the succession: biostratigraphical studies need, therefore, to be carried out with particular care.