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Decoupling of carbon isotope records across the Tithonian and Berriasian
Madeleine Larissa Vickers, Johannes Monkenbusch, Gregory D. Price, Nicolas Rudolph Thibault, Christoph Korte, Jennifer Galloway, Steve Grasby

Building: Muséum d'Histoire Naturelle de Genève
Room: Lobby /Hall/
Date: 2018-12-05 11:02 AM – 11:05 AM
Last modified: 2018-12-01

Abstract


The published carbonate δ13C record across the Jurassic-Cretaceous boundary (from the base of the Kimmeridgian to the base of the Valanginian), shows no major negative carbon isotope excursions (CIEs; see global δ13C stack of Price et al., 2016). This composite δ13Ccarbonate curve includes data from many sites, but is dominated by Tethysian data. The organic carbon δ13C record for this interval is much more limited, with published data from only a few sites in the northern hemisphere. Arctic δ13Corg data (from Svalbard and Arctic Russia; Hammer et al., 2012; Zakharov et al., 2014; Koevoets et al., 2016) show a prominent negative excursion of c. 4 ‰ in the Tithonian, whereas δ13Corg data from Dorset, UK (Morgans-Bell et al., 2001), and the North Sea (Turner et al., 2018), do not show such an excursion. It may be that the lack of a prominent negative excursion in these Tethysian and Boreal records relates to limited coverage of the key Tithonian interval. However, it may be that pools of organic carbon and dissolved inorganic carbon during this time were effectively decoupled, or there was latitudinal decoupling between the Arctic and Tethysian/Boreal Seas. A high Arctic carbonate dataset and more extensive Tethysian organic carbon data is necessary to resolve the cause of this Arctic organic CIE.