EGU2020-10864, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-10864
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The continental Middle Miocene Climatic Transition in Southern Europe as derived from clumped isotope analyses

Niklas Löffler1,2, Andreas Mulch1,2, Wout Krijgsman3, Emilija Krsnik1,2, and Jens Fiebig1,2
Niklas Löffler et al.
  • 1Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, 60325 Frankfurt (Main), Germany (niklas.loeffler@senckenberg.de)
  • 2Institute of Geosciences, Goethe University, Altenhoeferallee 1, 60438 Frankfurt (Main), Germany
  • 3Paleomagnetic Laboratory “Fort Hoofddijk”, Utrecht University, Budapestlaan 17, 3584 CD Utrecht, The Netherlands

Reconstructing Cenozoic terrestrial paleoclimate is frequently limited by temporal resolution and suitable quantitative tools to reliably assess changes in temperature and aridity. The dynamics of ocean temperatures1 and chemistry2, varying pCO23, and faunal assemblages are known to a certain extent, however, terrestrial data on temperatures, which are mostly indirectly derived from fossil assemblages and palynologycal data4 are rare. This study contributes to the understanding of the dynamics and variability of terrestrial temperatures during one of the most extreme Neogene climate changes, the Middle Miocene Climate Transition (MCT). The comparison of pCO2 forecasts for the coming century and reconstructed Mid-Miocene pCO2 levels suggest that the Mid-Miocene is an important time interval for ascertaining suitable model projections of the future anthropogenic impact on climate. In order to establish an appropriate understanding and modeling of the natural variability of the European/Mediterranean climate system, quantitative climate information of the European continental Mid-Miocene is mandatory. This would facilitate the identification of main drivers of climate evolution in an area which is exposed to the present climate change and its subsequent natural hazards.

 

This study presents a profound and well-dated terrestrial clumped isotope (Δ47) paleosoil carbonate dataset from Spain that ranges from 13.0 to 15.1 Ma (100 kyr resolution) and hence covers an interval that was previously classified as the MCT. The Δ47 data is supported by stable carbon and oxygen isotope analyses that are in agreement with previously published continental and oceanic records. A distinct decline in apparent Δ47-based temperatures between 13.7 and 14.1 Ma reveals a substantial drop in continental temperatures and indicates changes in seasonality of pedogenic carbonate formation. The major cooling thereby coincides with a change in Milanković periodicities and can be linked to oceanic isotope records5. While the transition into the MCT shows a high temperature variability indicating varying environmental conditions, calculated oxygen isotopic values of the soil water point to a rather stable moisture source across the MCT in Southern Europe.

 

1: Super, J. R., Thomas, E., Pagani, M., et al. (2018) North Atlantic temperature and pCO2 coupling in the early-middle Miocene. Geology, 46(6), 519-522.

2: Pearson, P. N., and Palmer, M. R. (1999) Middle Eocene seawater pH and atmospheric carbon dioxide concentrations. Science, 284(5421), 1824-1826.

3: Pagani, M., Freeman, K. H., and Arthur, M. A. (1999) Late Miocene atmospheric CO2 concentrations and the expansion of C4 grasses. Science, 285(5429), 876-879.

4: Lewis, A. R., Marchant, D. R., Ashworth, A. C., et al. (2008) Mid-Miocene cooling and the extinction of tundra in continental Antarctica. Proceedings of the National academy of Sciences.

5: Holbourn, A., Kuhnt, W., Clemens, S., et al. (2013) Middle to late Miocene stepwise climate cooling: Evidence from a high resolution deep water isotope curve spanning 8 million years. Paleoceanography, 28(4), 688-699.

How to cite: Löffler, N., Mulch, A., Krijgsman, W., Krsnik, E., and Fiebig, J.: The continental Middle Miocene Climatic Transition in Southern Europe as derived from clumped isotope analyses, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10864, https://doi.org/10.5194/egusphere-egu2020-10864, 2020