EGU2020-9074
https://doi.org/10.5194/egusphere-egu2020-9074
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Exploring Mesozoic Climates - Modeling and Evaluation of Proxy Distributions

Jan Landwehrs1,2, Georg Feulner2, Matthias Hofmann2, Stefan Petri2, Benjamin Sames1, and Michael Wagreich1
Jan Landwehrs et al.
  • 1University of Vienna, Department of Geodynamics and Sedimentology, Wien, Austria (jan.landwehrs@univie.ac.at)
  • 2Potsdam Institute for Climate Impact Research, Earth System Analysis, Potsdam, Germany

The Mesozoic Era (~252-66 Ma) is a decisive period in Earth’s history. It is marked by a tectonic transition from the Pangea supercontinent towards a modern continental configuration as well as the ecological success of the dinosaurs and the evolution of mammals, flowering plants, stony corals and important groups of planktic calcifiers. The Mesozoic is generally considered as a greenhouse climate period, with especially high global temperatures during the Triassic and the Late Cretaceous. Here, we present novel modeling results on the evolution of global climatic conditions through the Mesozoic.

An ensemble of equilibrium climate states for 40 geological timeslices between 255 and 60 Ma is simulated with the CLIMBER-3α Earth System Model of Intermediate Complexity. The influence of changing paleogeography, sea level, vegetation cover, solar luminosity, orbital configuration and atmospheric CO2 concentration is systematically tested based on constraints from published geological proxy reconstructions and previous modeling work.

Atmospheric pCO2 is found to be the strongest driver of global mean temperatures, which are generally elevated above the present and reach 20°C in the Late Triassic to Early Jurassic and the mid-Cretaceous if a recently published pCO2 proxy compilation is employed. The simulated seasonal latitudinal shift of high precipitation zones exhibits a maximum during the mid-Triassic to Early Jurassic and therefore supports the notion of a “Megamonsoon” during this time. Simulated humid and arid climate zones generally agree well with spatial distributions of geologic climate indicators like coal and evaporites, although some discrepancies exist. The same applies to the correlation of fossil stony coral reef distributions with regions where seawater temperatures would have been suitable for (modern) coral reefs. We will discuss which changes of Earth System parameters throughout the Mesozoic can best explain shifts in these distributions.

How to cite: Landwehrs, J., Feulner, G., Hofmann, M., Petri, S., Sames, B., and Wagreich, M.: Exploring Mesozoic Climates - Modeling and Evaluation of Proxy Distributions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9074, https://doi.org/10.5194/egusphere-egu2020-9074, 2020

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Presentation version 1 – uploaded on 17 Apr 2020
  • CC1: Comment on EGU2020-9074, Mathieu Martinez, 01 May 2020

    Very interesting study, showing the large scale changes in seasonal temperatures and precipitation. I'm interested at what could happen at higher frequency. It seems that after the Early Jurassic, the warmest seasons remain very arid in the northwestern margin of the Tethys Ocean (I see there lots of haches during the warmest season in the Northern Hemisphere). Am I wrong? What would be the consequence of increasing or decreasing the seasonal contrast by modulating, for instance, the eccentricity cycles?

    • AC1: Reply to CC1, Jan Landwehrs, 01 May 2020

      Thank you Mathieu!
      Linking orbital climatic effects in geological proxies and models can certainly provide important insights. We also performed simulations with some different orbital configurations for a subset of the timeslices (not included here). From a glance at existing plots it appears that this region is indeed simulated to be relatively arid but influenced by precession (dryer at Southern Hemisphere Summer Maximum insolation) at high eccentricity. 
      We'll try to publish the presented data soon and we will certainly look deeper into the orbital effects at a later time. I'll read your 2015 PNAS paper (wanted to do this anyway) and would be happy to discuss possible conclusions regarding your work.
      With kind regards,
      Jan Landwehrs

      • CC2: Reply to AC1, Mathieu Martinez, 01 May 2020

        Many thanks for your answer, very informative! Looking forward to discuss about your study

  • CC3: Comment on EGU2020-9074, Alexander Orkhonselenge, 04 May 2020

    Dear Colleague, 

    Great work! Could you let me know the dot- and cross-patterned areas, please? I would like to see the Cenozoic climates in your further work!

    Best regards,

    Orkhon