The Global Boundary Stratotype Section and Point for the base of the Danian Stage (Paleocene, Paleogene, “Tertiary”, Cenozoic) at El Kef, Tunisia — Original definition and revision

Abstract

The Cretaceous/Paleogene (K/Pg) Working Group, after many years of studies, voted to define the Global Stratotype Section and Point (GSSP) for the base of the Danian Stage at the base of the boundary clay at a section near El Kef, Tunisia. The GSSP was approved by the International Commission on Stratigraphy (ICS) and ratified by the International Union of Geological Sciences (IUGS) in 1991. Nevertheless, the GSSP was not officially published, although some papers dealing with geological aspects of the K/Pg boundary at El Kef have been published and this is quite well known. In April 2006, the GSSP was revisited, a marker was put in place and protection of the site was requested. Many correlation criteria are present at the GSSP of which the most useful are the meteorite impact evidence (iridium anomaly, Ni-rich spinel, etc.) and the mass extinction of planktic micro-and nannofossils. This event coincides with the GSSP, allowing us to propose that the K/Pg boundary is marked exactly by the moment of the meteorite impact, which implies that all the sediments generated by the impact belong to the Danian. This definition solves problems of correlation in the Yucatan peninsula (Mexico) and its surroundings.

Climate and sea‐level changes across a shallow marine Cretaceous–Palaeogene boundary succession in Patagonia, Argentina

“…Molina et al . ) is not preserved at San Ramón. This suggests a possible small stratigraphic hiatus at the boundary.…”

Calcareous nannofossil biostratigraphy: historical background and application in Cenozoic chronostratigraphy

“…The GSSP of Danian Stage was ratified in 1991 (Molina et al . ) at the El Kef section (Tunisia); this boundary coincides with the base of the Palaeogene system (Palaeocene series) and was defined at the base of a dark clay layer that documents the last among the big five mass extinctions. Calcareous nannofossils suffered a profound extinction event followed by a relatively slow recovery.…”

Geophysical Characterization of the Chicxulub Impact Crater

“…In the seismic profiles, we have mapped the base of the post‐impact Cenozoic sediments as the top of the K‐Pg deposit. Although the formal boundary between the Cretaceous and the Paleogene is at the base of all impact‐related deposits [ Molina et al ., ] that depth within the crater is difficult to determine precisely, and thus following the Schulte et al . [] discussion of a proximal impact sequence in Mexico, we refer to the entire thickness of impact deposits below the post‐impact Paleogene sediments as the K‐Pg event deposit.…”