Climate-ocean interactions in the eastern subtropical Cretaceous Atlantic: Integrating long-term and punctuated Late Aptian to Early Albian climate records from the Mazagan Plateau (DSDP Site 545)
Zusammenfassung der Projektergebnisse
Marine biotic crises in the Mesozoic greenhouse have been linked to episodes of extreme global warmth, often associated with widespread ocean anoxia. However, there is also evidence that cooling may have caused similar crises. Convincing support for such a scenario is pending as robust temperature records are rare and not sufficiently detailed to confirm relationships between cooling and biotic turnover. Results of a high-resolution study, combining TEX86-derived sea-surface temperatures (SST), organic and carbonate δ13C isotopes, calcareous nannofossil studies, and biogeochemical modeling, constrain the timing and magnitude of late Aptian cooling (~114-116 Ma) and associated biotic crises. Our results show a two million-year-long surface-water cooling by ~5 °C that coincided with a positive ~1.5 to 2 ‰ carbon isotope excursion in the global carbon cycle, a crisis of the plankton population of the North Atlantic demonstrated by the decline in calcareous nannoconids and planktic foraminifer abundance, and increasing surface-water productivity. Results from combined climate- and biochemical modeling suggests the burial of ~812,000 Gigatons (Gt) of carbon over ~2.5 Myrs is need to explain the δ13C isotope excursion. We identify the evolving Atlantic Southern Ocean and Tethys basins as important sinks where ~50% of the total global carbon was buried. This study provides evidence that global cooling during greenhouse periods can cause perturbations to marine ecosystems and biogeochemical cycles at scales comparable to those associated with global warming.
Projektbezogene Publikationen (Auswahl)
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(2011): Long term cooling and punctuated climate events recorded in Late Aptian to Early Albian sediments from the eastern subtropical Atlantic (Mazagan Plateau, DSDP Site 545). 25nd IMOG, Interlaken, Switzerland
McAnena, Herrle, J., Hoffmann, P., Wagner, T.
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(2012). Evidence for long term cooling and short punctuated climate events at the Aptian-Albian boundary in the subtropical Atlantic (Mazagan Plateau, DSDP Site 545), European Geosciences Union General Assembly 2012, Vienna, Austria, 22.-27. April 2012
McAnena, A., J. Herrle, A. Griesand, T. Wagner, H.M. Talbot,, P. Hofmann
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(2012). Sea surface temperature development in the subtropical North Atlantic during the Aptian: Implications for Oceanic Anoxic Event 1a and the Late Aptian Cold Snap. International Conference of the Geologische Vereinigung and Sediment, Hamburg, Germany, 23-28 September 2012
Hofmann, P., McAnena, A., Wiegand, R., Handley, L., Wagner, T., Talbot, H.M., Herrle, J.
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2012. Low sea-surface temperatures during the Aptian-Albian transition (mid-Cretaceous epoch) and the effect on the evolution of marine calcifying organisms" GV and SEDIMENT meeting 2012 in Hamburg: Land and Sea: Processes and Products 23.09.-28.09.2012
Griesand, A., Herrle, J.O., Hofmann, P., Wagner, T.
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(2013). Implications of the Late Aptian Cold Snap. IODP/ICDP Meeting 2013, 25-27 March, Freiberg, Germany
Hofmann, P., McAnena, A., Wagner, T., Talbot, H.M., Pross, J., Herrle, J., Floegel, S.
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(2013). Sea surface temperature development and carbon isotope disturbance in the subtropical North Atlantic: Implications for the Late Aptian Cold Snap. IMOG, September 2013, Tenerife, Spain
Wagner, T., Hofmann, P., McAnena, A., Talbot, H.M., Herrle, J., Pross, J., Floegel, S.
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Atlantic cooling associated with a marine biotic crisis during the mid-Cretaceous period. Nature Geosciences 6, 558-561 (2013)
McAnena, A., Flögel, S., Hofmann, P., Herrle, J.O., Griesand, A., Pross, J., Talbot, H.M., Rethemeyer, J., Wallmann, K., Wagner, T.
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(2014). Gateway opening of the South Atlantic Ocean: New high resolution insights from the Aptian to Albian Falkland Plateau (DSDP Site 511). IODP/ICDP Meeting 2014, March, Erlangen, Germany
Hofmann, P., Wagner, T., Herrle, J., McAnena, A.
