The Anglo-Belgo-Paris Basin, historical cradle of the Paleogene stratigraphy since the XVIIIth century, is known by the presence of very specific so-called “Sparnacian” deposits (very diverse and laterally highly variable, predominantly lagoonal to terrestrial facies), which encompass the short stratigraphic interval of the Paleocene-Eocene Thermal Maximum (PETM). Due to the insufficient paleontological record, the “Sparnacian” succession of the Paris and Dieppe-Hampshire Basins still needs a robust chronostratigraphic correlation with other Paleogene records worldwide. In order to refine the stratigraphy of the Thanetian-Lower Ypresian succession in northern France a number of cores and outcrop sections have been investigated palynologically. As a result, an updated version of the Dinoflagellate cyst zonation for the Paris and Dieppe Basins is proposed and contains six new or revised Biozones for this stratigraphical interval: Alisocysta margarita, Apectodinium hyperacanthum, Apectodinium-extreme acme, Biconidinium longissimum-acme, Dracodinium astra, and Axiodinium lunare/Stenodinium meckelfeldense. Based on combined bio-, litho- and chemostratigraphic data, it appears that the dinocyst assemblages, corresponding to the PETM event interval (“Sparnacian” deposits, Soissonnais and upper Mortemer Formations with the most negative 13δCorg values between -27 and -32 ‰ PDB), are characterized by an extreme acme of Apectodinium spp. (70-98%) in both basins, sometimes alternating with an extreme acme of a few gonyaulacoid groups in the Dieppe Basin. Dinocyst assemblages from the PETM interval contain a significant number of atypical, longer specimens of Apectodinium parvum, which could represent an ecological onshore substitute of species Axiodinium augustum in the Paris and Dieppe-Hampshire Basins. The establishment of a new Biconidinium longissimum-acme Zone suggests the absence of an important stratigraphical hiatus previously inferred for the Paris Basin.
Dinoflagellate Cyst Biostratigraphy of Late Paleocene and Early Eocene Sediments from Holes 552, 553A, and 555, Leg 81, Deep Sea Drilling Project (Rockall Plateau)