EGU General Assembly 2020
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Thirty-five million years of changing climate – carbon cycle dynamics

David De Vleeschouwer1, Anna Joy Drury2, Maximilian Vahlenkamp1, Diederik Liebrand1, Fiona Rochholz1, and Heiko Pälike1
David De Vleeschouwer et al.
  • 1Universität Bremen, MARUM, MARUM, Bremen, Germany (
  • 2University College London Earth Sciences, London, United Kingdom

Fifty-one years of scientific ocean drilling through the International Ocean Discovery Program (IODP) and its predecessors generated a treasure trove of Cenozoic climate and carbon cycle dynamics. Yet, it remains unclear how climate system and carbon cycle interacted under changing geologic boundary conditions. Here, we present the carbon isotope (d13C) megasplice, documenting deep-ocean d13C evolution since 35 million years ago (Ma). We juxtapose the d13C megasplice with its d18O counterpart and determine their phase-difference on ~100-kyr eccentricity time-scales. This analysis uncovers that 2.4-Myr eccentricity modulates the in-phase relationship between d13C and d18O during the Oligo-Miocene (34-6 Ma), potentially related to changes in continental weathering. At 6 Ma, a striking switch from in-phase to anti-phase behaviour occurs, signalling a threshold in the climate system. We hypothesize that Arctic glaciation and the emergence of bipolar ice sheets enabled eccentricity to exert a major influence on the size of continental carbon reservoirs. Our results suggest that a reverse change in climate - carbon cycle interaction should be anticipated if CO2 levels rise further and we return to a world of unipolar ice sheets.

How to cite: De Vleeschouwer, D., Drury, A. J., Vahlenkamp, M., Liebrand, D., Rochholz, F., and Pälike, H.: Thirty-five million years of changing climate – carbon cycle dynamics, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21479,, 2020.


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