FORAMINIFERAL ASSEMBLAGES FROM THE LATE LOWER AND MIDDLE CENOMANIAN OF SPEETON (NORTH YORKSHIRE, UK) - RELATIONSHIPS WITH SEA-LEVEL FLUCTUATIONS AND WATERMASS DISTRIBUTION

Twenty-seven marl samples from the late Lower and Middle Cenomanian of Speeton (North Yorkshire, UK) have been studied and six benthic foram iniferal assemblages (A to F) have been recognized by cluster analysis . These assemblages can be classified according to their constituent a gglutinated foraminifera. Assemblages characterized by high abundances of non-calcareous agglutinates (A and E) have low numbers of planktic s and are associated with cold-water pulse faunas of mid Russian affin ity (belemnites, brachiopods and bivalves). These are interpreted as r epresenting a cold North Sea watermass. Assemblages characterized by h igh abundances of planktics (B and C) are associated with pulse faunas that lack cold-water elements and are interpreted as representing a w arm watermass. The foraminiferal assemblages are also related to sea-l evel fluctuations and individual assemblages were probably depth contr olled. The assemblages can, therefore, be used to construct a sea-leve l curve and this agrees with the placement of critical sequence strati graphic surfaces (e.g. sequence boundaries and flooding surfaces).