Abstract
Variation in dinoflagellate cyst assemblages from the Turonian of southern England is addressed. Little recent work has been done on the palynomorphs from this part of the Upper Cretaceous. Sampling every 1-2 m of the succession from three areas (Sussex, Kent and the Isle of Wight), together with recording of sedimentological and macropalaeontological data provide a good basis for a biostratigraphical analysis. The dinoflagellate cyst assemblages recovered are dominated by several species, notably Cyclonephelium distinctum, C. membraniphorum, Senoniasphaera rotundata and Heterosphaeridium difficile. The base of the Turonian is redefined biostratigraphically by the first appearance H. difficile. Using the ranges and acmes of this and other species, three palynozones are proposed for the Turonian of Sussex and Kent. Some species referred to in open nomenclature are discussed, namely: ?Microdinium sp. A, Litosphaeridium sp. A, Senoniasphaera sp. A, Odontochitina operculata formae A and B, and Canningia sp. B. Turonian dinoflagellate cyst assemblages are of particular interest to palynologists because the composition of all microplankton groups are known to have been strongly affected at the end of the Cenomanian by a global oceanic anoxic event. The recovery of the dinoflagellate cyst 'population' after this event is documented.
Published Version
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