THE DOGGER OF THE BOULONNAIS (NORTHERN PARIS BASIN) - NEW CHRONOLOGICAL AND SEQUENCE STRATIGRAPHIC FRAMEWORK OF THE JURASSIC CARBONATE FORMATIONS ON THE MARGIN OF THE LONDON-BRABANT MASSIF

New lithological units overlying transgressively the Palaeozoic are de scribed in the Dogger of the Boulonnais. Both litho- and biofacies ind icate continental to open marine depositional environments. Palaeowate r-depth variations suggest a sequence stratigraphic interpretation. Br achiopod associations, ammonites and dinoflagellate cysts bring new bi ochronological data: the oldest dated deposits are from the Late Bajoc ian-Early Bathonian, whereas the first marine ones are from the earlie st Upper Bathonian. The main transgressive or regressive events are sy nchronous with those described elsewhere in the Paris basin. However, the drowning of the basement appears to have happened later in the Bou lonnais.