Coniacian–Campanian palynology, carbon isotopes and clay mineralogy of the Poigny borehole (Paris Basin) and its correlation in NW Europe

Abstract

The Poigny borehole near Provins (Seine-et-Marne) provides the most complete single pristine section through the Upper Cretaceous Chalk of the Paris Basin. A well preserved and diverse palynoflora including 236 species and subspecies of organic-walled dinoflagellate cysts (dinocysts) is documented from the borehole, together with a high-resolution carbon-isotope curve (${\delta }^{13}$C$_{\mathrm{carb}}$) for the Coniacian–Campanian interval. Integration of the palynological and ${\delta }^{13}$C$_{\mathrm{carb}}$ data provides a basis for a chemostratigraphic and biostratigraphic correlation to England and Germany. Carbon isotope events (CIEs) are used to refine the placement of sub-stage boundaries in the core, and to calibrate and correlate distinctive palynological events with those from other European sections. Thirty-three palynological events in the upper Coniacian–Campanian, judged to be of biostratigraphic significance, are described. Palynological assemblages, the peridinioid/gonyaulacoid (P/G) dinocyst ratio and clay mineralogy are compared to depositional sequences and implicate sea-level as a major driver of palaeoenvironmental change.

Keywords

• Sea-level change
• Poigny borehole
• Dinoflagellate cysts
• Biostratigraphy
• Santonian
• Campanian
• Carbon isotopes
• Sea-level change