Vol. 29 No.4 December 2006

Journal of International Geoscience

Published by the International Union of Geological Sciences

by Eustoquio Molina¹, Laia Alegret¹, Ignacio Arenillas¹, José A. Arz¹, Njoud Gallala²,Jan Hardenbol³, Katharina von Salis⁴, Etienne Steurbaut⁵, Noël Vandenberghe⁶, and Dalila Zaghbib-Turki²

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

1 Departamento de Ciencias de la Tierra, Universidad de Zaragoza. E-50009 Zaragoza, Spain.
2 Département de Geologie, Faculté des Sciences de Tunis, 2092 Tunis El Manar, Tunisia.
3 Global Sequense, Chronostratigraphy Inc., 826, Plainwood Drive, Houston, Texas 77079-4227, USA.
4 Via Maistra 9, CH-7513 Silvaplana, Switzerland.
5 Royal Belgian Institute of Natural Sciences, Vautierstraat 29, B-1000 Brussels, Belgium.
6 Departement Geogra!e-Geologie, Afdeling Geologie, B-3000 Leuven, Belgium.

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.

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