A new sediment core from the Bedoulian (Lower Aptian) stratotype at Roquefort-La Bédoule, SE France Janne Lorenzen a, * , Wolfgang Kuhnt a , Ann Holbourn a , Sascha Flögel b , Michel Moullade c, d , Guy Tronchetti c a Institute of Geosciences, University of Kiel, Ludewig-Meyn-Str.14, 24118 Kiel, Germany b GEOMAR, Wischhofstr. 1-3, 24148 Kiel, Germany c Université de Provence, Marseille, Case 67, 3 Pl. Victor Hugo, 13331 Marseille Cedex 03, France d Muséum d’Histoire Naturelle de Nice, 60 Bd Risso, 06300 Nice, France article info Article history: Received 3 June 2011 Accepted in revised form 23 March 2012 Available online xxx Keywords: Aptian OAE 1a La Bédoule Bedoulian Stable isotopes abstract New drill cores from the Lower Aptian historical stratotype at Roquefort-La Bédoule (SE France) provide continuous high-resolution geochemical and isotope records which closely track the onset of OAE 1a in a subtropical intra-shelf basin (South Provençal Basin). The drilling operation recovered a total of 180 m of undisturbed sediments in three holes. The lowermost 67 m correspond to the Bedoulian (core LB1) and are here analyzed in high-resolution using geochemical proxies (stable carbon isotopes, stable oxygen isotopes, and carbonate content) and foraminiferal biostratigraphy. Pervasive bioturbation through core LB1 suggests mostly oxygenated bottom water conditions with transient dysoxic episodes, as shown by higher pyrite and glauconite concentrations within the marlstones. Unprecedented resolution over the negative d 13 C excursion preceding OAE 1a (segment C3) reveals a characteristic double trough extending over w5.5 m in core LB1. This long-lasting negative excursion was possibly linked to multiple pulses of enhanced CO 2 release to the atmosphere. Estimated sedimentation rates of 1.6e2 cm/kyr indicate that the negative d 13 C excursion lasted >200 kyr, while the main positive carbon isotope shift (segment C4) had a duration of >300 kyr. Fluctuations in d 18 O suggest transient episodes of climate warming and cooling at the northern margin of the Tethys or even on a more global scale prior to the onset of OAE 1a. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction: drilling location, research history The historical stratotype area of the Lower Aptian (Bedoulian) is located between the towns of Cassis and Roquefort-La Bédoule, about 16 km SE of Marseille (SE France) (Fig. 1). Here, the Bedoulian series corresponds to an expanded, continuous succession of clay-rich marlstones and limestones that were deposited in an intra-shelf basin along the northern Tethys margin (Fig. 2). The so- called South Provençal Basin was located on a carbonate platform (North Provençal Platform) and had no direct connection to the Vocontian Basin or other areas of high terrigenous flux. Since the 19th century, the ammonite-rich beds of this area were intensely excavated by the cement industry in several quarries. Its fossil richness established La Bédoule as a location of major geological interest, and it was chosen by Toucas (1888) as the type-locality of the Lower Aptian substage. Initially known as a rich fossiliferous outcrop over more than a century, the stratotype was then inves- tigated with more advanced palaeontological, biostratigraphical and sedimentological methods. This new integrated approach was initiated at the time of the Lower Cretaceous Congress of Lyon (1963) (Fabre-Taxy et al., 1965), and was then continuously devel- oped during the last five decades (Barrier, 1977; Moullade et al., 1980, 1998d; Busnardo, 1984; Conte, 1994; Delanoy et al., 1997; Ropolo et al., 2006; Moullade and Tronchetti, 2010). Initial stable isotope measurements (Kuhnt et al., 1998) on outcrop samples revealed that the Cassis-Roquefort-La Bédoule sedimentary archive provides unprecedented resolution over the onset, development and termination of the early Aptian Oceanic Anoxic Event (OAE) 1a. Chemostratigraphy and isotope stratigraphy were developed to constrain the timing and duration of the d 13 C excursion, which characterizes OAE 1a (Renard et al., 2005; Kuhnt et al., 2011). The published carbon isotope record from Cassis- Roquefort-La Bédoule (Kuhnt et al., 1998, 2011; Moullade et al., 1998a; Kuhnt and Moullade, 2007) shows a distinct positive * Corresponding author. Tel.: þ49 431 880 5073; fax: þ49 431 880 4376. E-mail address: lorenzen@gpi.uni-kiel.de (J. Lorenzen). Contents lists available at SciVerse ScienceDirect Cretaceous Research journal homepage: www.elsevier.com/locate/CretRes 0195-6671/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.cretres.2012.03.019 Cretaceous Research xxx (2012) 1e11 Please cite this article in press as: Lorenzen, J., et al., A new sediment core from the Bedoulian (Lower Aptian) stratotype at Roquefort-La Bédoule, SE France, Cretaceous Research (2012), doi:10.1016/j.cretres.2012.03.019