EGU23-17389, updated on 14 Jun 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A millennial-scale record of mean annual air temperatures spanning 70 ka over the Cretaceous-Paleogene boundary

Lauren O'Connor1, Rhodri Jerrett1, Gregory Price2, Bart van Dongen1, Emily Crampton-Flood1, and Sabine Lengger2
Lauren O'Connor et al.
  • 1Department of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
  • 2School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK

The Cretaceous-Paleogene (K-Pg) boundary experienced major environmental perturbations due to volcanism and bolide impact, as well as the most famous mass extinction in geologic history. However, the response of the climate system to these drivers at different timescales, and thus their relationship to the mass extinction is highly debated. In particular, the role of climate change in biodiversity patterns immediately preceding the boundary is poorly understood. 

Lipids from fossil peats (coals) provide an opportunity to reconstruct terrestrial temperatures across the Cretaceous–Paleogene boundary at a millennial-scale resolution. Here we present mean annual air temperature records spanning ~70 ka over the K-Pg boundary, from sites across North America (palaeolatitudes 45–55 degrees N). Our data show that temperatures ranged from 16–29 degrees C, more than 10 degrees C higher modern temperatures at equivalent latitudes in North America.

Using 5-ka temporal bins, our data show that MAATs peaked at ~26 degrees C in the last millennia of the Cretaceous, following 35 ka of warming from ~23 degrees C. Peak warmth was followed by ~5 degrees C cooling over the following 30 ka. We observe no “impact winter” nor a spike in temperature immediately following the boundary. If such phenomena occurred, their duration was below the resolution of our record: ~1 ka. Our record also shows a previously unrecognised brief interval of cooling from 10 to 5 ka pre-boundary.

Our study places new bounds on millennial-scale trends in MAAT change in the terrestrial realm and demonstrates large and rapid temperature swings across the K-Pg interval. These data allow for improved understanding of the role of climate in the decline of Cretaceous flora and fauna and may help elucidate the relative influence of volcanism and bolide impact on terrestrial temperatures.

How to cite: O'Connor, L., Jerrett, R., Price, G., van Dongen, B., Crampton-Flood, E., and Lengger, S.: A millennial-scale record of mean annual air temperatures spanning 70 ka over the Cretaceous-Paleogene boundary, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17389,, 2023.