A new sediment core from the Bedoulian (Lower Aptian) stratotype at Roquefort-La Bédoule, SE France.

Lorenzen, Janne, Kuhnt, Wolfgang, Holbourn, Ann, Flögel, Sascha, Moullade, Michel and Tronchetti, Guy (2013) A new sediment core from the Bedoulian (Lower Aptian) stratotype at Roquefort-La Bédoule, SE France. Cretaceous Research, 39 . pp. 6-16. DOI 10.1016/j.cretres.2012.03.019.

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Supplementary data:

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 δ13C excursion preceding OAE 1a (segment C3) reveals a characteristic double trough extending over ∼5.5 m in core LB1. This long-lasting negative excursion was possibly linked to multiple pulses of enhanced CO2 release to the atmosphere. Estimated sedimentation rates of 1.6–2 cm/kyr indicate that the negative δ13C excursion lasted >200 kyr, while the main positive carbon isotope shift (segment C4) had a duration of >300 kyr. Fluctuations in δ18O 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.

Document Type: Article
Additional Information: WOS:000312685000002
Keywords: Geochemistry; Aptian; OAE 1a; La Bédoule; Bedoulian; Stable isotopes; OCEANIC ANOXIC EVENT; CARBON-ISOTOPE STRATIGRAPHY; LIVELLO SELLI; PACIFIC-OCEAN; LOW LATITUDES; TETHYS; 1A; DEPOSITION; EVOLUTION; SECTION
Research affiliation: OceanRep > SFB 754 > A7
Kiel University
OceanRep > SFB 754
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
UNSPECIFIED
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.cretres.2012.03.019
ISSN: 0195-6671
Projects: SFB754, Future Ocean
Expeditions/Models/Experiments:
Date Deposited: 25 Apr 2012 08:10
Last Modified: 22 Sep 2016 08:57
URI: http://oceanrep.geomar.de/id/eprint/14262

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