EGU General Assembly 2022
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Integrated calcareous plankton biostratigraphy and stable isotopes stratigraphy of Cenomanian-Turonian interval of Breonio and Quero sections (central-western Tethys)

Michela Simonato1, Silvia Gardin2, Luca Giusberti1, Valeria Luciani3, Nereo Preto1, Guido Roghi4, Simone Barbieri5, Federico Xausa1, and Eliana Fornaciari1
Michela Simonato et al.
  • 1Department of Geosciences, University of Padua, Padua, Italy (
  • 2Center for Research on Palaeobiodiversity and Palaeoenvironments, Sorbonne University, Paris, France (
  • 3Department of Physics and Earth Sciences, University of Ferrara, Ferrara, Italy (
  • 4Institute of Geosciences and Earth Resources (IGG-CNR), Padua, Italy (
  • 5Trento, Italy (

The late Cenomanian-Turonian interval is characterized by major changes in the global carbon cycle, identified by stable carbon isotope excursions with associated climatic variations (e.g., OAE2, Late Turonian Events). These changes are linked to significant paleoceanographic modifications that impacted the biota, especially primary producers (e.g., calcareous plankton), forcing extinctions and evolutionary radiations. A reliable biostratigraphy is an essential tool to correlate both environmental and biotic changes worldwide.

Calcareous nannofossils and planktic foraminifera are well recognized as useful markers for biostratigraphy and paleoecological studies. However, the Cenomanian-Turonian calcareous nannofossil biohorizons are still poorly constrained because the nannofossil assemblages suffer from marked provincialism and taxonomic uncertainty that can blur their biochronological potential.

In order to improve the calcareous nannofossil biostratigraphic scheme of the late Cenomanian-Turonian interval, we present new data from the Breonio section (northeastern Italy), in the southwestern part of the Trento Plateau, and from the Quero section (northeastern Italy), located in the western Belluno Basin (central-western Tethys).

The analyses of calcareous nannofossil and planktic foraminiferal assemblages were integrated with the δ13C, δ18O and CaCO3 curves. The δ13C values highlight several positive, global, stable carbon isotope shifts in both sections. The CaCO3 signal of the Quero section suggests that the isotopic signal is pristine because the CaCO3 values are not coupled with δ13C isotope shifts. On the contrary CaCO3 curve seems generally to reflect the lithological signal. On the basis of biostratigraphic data the detected positive shifts have been correlated with the late Cenomanian-Turonian events, specifically, the Oceanic Anoxic Event 2, Holywell, Round down, Pewsey, and Late Turonian Events 1, 2, 3. The stratigraphic position of biohorizons with respect to the globally recognized δ13C excursions can provide a valuable mean to evaluate their potential synchronism/diachronism.

Our preliminary data show a good correspondence with the recent calcareous nannofossil-planktic foraminiferal integrated scheme (Geologic Time scale 2020; Gale et al. 2020) for the late Cenomanian-Turonian interval, although some calcareous nannofossil markers were not recorded. Interestingly, some «standard» and additional calcareous nannofossil events are promising proxies for the Late Turonian Events 1 and 2.



Gale A.S., Mutterlose J. & Batenburg S. (2020). The Cretaceous Period, in Gradstein F.M. et al., eds., Geologic Time Scale 2020: Boston, Elsevier, pp. 1023-1086.

How to cite: Simonato, M., Gardin, S., Giusberti, L., Luciani, V., Preto, N., Roghi, G., Barbieri, S., Xausa, F., and Fornaciari, E.: Integrated calcareous plankton biostratigraphy and stable isotopes stratigraphy of Cenomanian-Turonian interval of Breonio and Quero sections (central-western Tethys), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11890,, 2022.