Abstract: North Atlantic Neogene Dinoflagellate Cyst Chronostratigraphy: True Business Horizons

Laurent De Verteuil, Martin J. Head, Geoffrey Norris

Knowledge of Neogene dinocysts has mushroomed over the last ten years. We present a state-of-the-art synthesis of the field, based on a decade of taxonomic and stratigraphic research in the North Atlantic and adjacent basins. At middle latitudes, over 50 highest and lowest occurrence events are synchronous between the eastern and western North Atlantic to within 1.5 Ma or better. Events that are diachronous by 2 Ma or more can often be related to water mass provenance and regional temperature gradients. All the dinocyst horizons are plotted against the most recent Neogene geochronology, which has a combined astronomic and radiometric calibration. Our stratigraphic data are principally from ODP Sites 902-905 on the continental slope and upper rise off New Jersey, DSDP Site 603 on the lower continental rise off New Jersey, and DSDP Site 610 in the Rockall Trough west of Ireland. Control at each site is provided by some combination of magnetostratigraphy, calcareous nannofossil stratigraphy, strontium isotope stratigraphy and seismic stratigraphy. In evaluating each horizon we considered the literature records from the rest of the North Atlantic and the Mediterranean. Our results demonstrate the importance of cyst wail ultrastructure in Neogene taxonomic determinations and the explosive potential of dinocyst stratigraphy for high-resolution basin analysis.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela