Integrated bio-chemostratigraphical correlations and climatic evolution across the Danian-Selandian boundary at low latitudes

• Published in: Palaeogeography, Palaeoclimatology, Palaeoecology
• Main Authors: Storme, Jean Yves, Steurbaut, Etienne, Devleeschouwer, Xavier, Dupuis, Christian, Iacumin, Paola, Rochez, Gaëtan, Yans, Johan
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2014
• Subjects: Biostratigraphy; Climatic perturbations; Danian-Selandian boundary; Decoupled carbon isotopes; Paleocene; pCO; North Atlantic
• Online Access: https://researchportal.unamur.be/en/publications/0cea2f57-5665-4836-8fee-75460b09c996; https://doi.org/10.1016/j.palaeo.2014.09.002; http://www.scopus.com/inward/record.url?scp=84907484516&partnerID=8YFLogxK

The Global Boundary Stratotype Section and Point for the base of the Selandian Stage is defined in the Zumaia section (Spain) at an abrupt change in lithology (base of Itzurun Formation), which coincides with the onset of a negative carbonate carbon isotope shift. However, this lithological change is not always very well expressed in other sections. In order to document the stratigraphic position of the Danian/Selandian boundary (DSB) on a more global scale, we have investigated three sections across the DSB, the Zumaia reference section (GSSP), the Loubieng section (auxiliary DSB reference section, France) and the Sidi Nasseur section (Tunisia). The Danian/Selandian boundary interval is subdivided and correlated throughout low latitudes, from the Altlantic Bay of Biscay to the Southern Tethys, on the basis of seven calcareous nannofossil and planktonic foraminiferal events (E-events). The base of the Selandian is proved to coincide with the end of the Braarudosphaera acme, which correlates with the lowest consistent occurrence (LCsO) of Lithoptychius aff. bitectus (=Fasciculithus janii sensu Steurbaut and Sztrákos, 2008) (event E4), but which is slightly posterior to the second radiation of the fasciculiths, up to now considered to represent the primary correlation tool of the DSB. A short-term δ 13 C org negative excursion, associated with an increase in pCO 2 is recorded at the very base of the Selandian. It is interpreted as a short period of global warming (hyperthermal), the duration of which is estimated at ~30kyr. It is followed in all the three studied sections by a long-term decoupled carbon isotope event, marked by increasing δ 13 C org and decreasing δ 13 C carb values. It may reflect a period of climatic cooling of a few 100kyr, interpreted as a possible precursor of the global cooling event, marking the late Paleocene in the North Atlantic realm. The integration of the biostratigraphic and the isotope data indicates major differences in sedimentation rates during the early Selandian in the studied ...