Orbital control on the timing of oceanic anoxia in the Late Cretaceous

• Main Authors: Batenburg, Sietske J., De Vleeschouwer, David, Sprovieri, Mario, Hilgen, Frederik J., Gale, Andrew S., Singer, Brad S., Köberl, Christian, Coccioni, Rodolfo, Claeys, Philippe, Montanari, Alessandro
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: ddc:550; North Atlantic
• Online Access: http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/42447; https://nbn-resolving.org/urn:nbn:de:hebis:30:3-424475; https://doi.org/10.5194/cp-2015-182; http://publikationen.ub.uni-frankfurt.de/files/42447/container.zip

The organic rich Livello Bonarelli formed as a result of oxygen deficiency and carbonate dissolution in the oceans during the Cenomanian/Turonian (C/T) transition. During this Ocean Anoxic Event 2 (OAE2), a combination of factors caused increased productivity, incomplete decomposition of organic matter and widespread deposition of black shales. Although these sediments are extensively studied, the exact extent, cause, timing and duration of oceanic anoxia are debated (Sinton and Duncan, 1997; Mitchell et al., 2008). Contrasting causal mechanisms have been suggested, including stratification of the water column (Lanci et al., 2010) versus intensification of the hydrological cycle driving a dynamic ocean circulation (Trabucho-Alexandre et al., 2010). Studies on trace-elemental and (radiogenic) isotope compositions of Cenomanian marine successions have suggested a volcanic origin of OAE2, by delivering nutrients to the semi-enclosed proto-North Atlantic (Zheng et al., 2013, and references therein; Du Vivier et al., 2014). Deciphering the importance of volcanic and oceanographic processes requires tight constraints on their relative timing. Regularly occurring black cherts and shales below the Livello Bonarelli demonstrate that oceanic conditions in the Umbria-Marche Basin were punctuated by episodes of regional anoxia from the mid-Cenomanian onwards. Their hierarchical stacking pattern suggests an orbital control on the deposition of organic rich horizons (Mitchell et al., 2008; Lanci et al., 2010). Stable carbon isotope data reveal that long-term 15 variations in eccentricity paced the carbon cycle (Sprovieri et al., 2013) and sea level changes (Voigt et al., 2006) of the Late Cretaceous. Here we investigate the role of orbital forcing on climate and the carbon cycle, and, specifically, on organic-rich sedimentation prior, during, and after OAE2. We also explore the potential for establishing an anchored astrochronology for the C/T interval in Europe. Recent improvements in the astronomical solution (La2011; ...