Clim. Past Discuss., 9, 5837-5854, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Climate of the Past (CP). Please refer to the corresponding final paper in CP.
A seasonality trigger for carbon injection at the Paleocene-Eocene thermal maximum
J. S. Eldrett1, D. R. Greenwood2, M. Polling3, H. Brinkhuis3, and A. Sluijs3
1Shell International Exploration and Production Inc. 3333 Highway 6, Houston, Texas 77082, USA
2Biology Department, Brandon University, 270 18th Street, Brandon, Manitoba, R7A 6A9, Canada
3Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Laboratory of Palaeobotany and Palynology, Budapestlaan 4, 3584 CD Utrecht, the Netherlands

Abstract. The Paleocene-Eocene thermal maximum (PETM) represents a ~170 kyr episode of anomalous global warmth ~56 Ma ago. The PETM is associated with rapid and massive injections of 13C-depleted carbon into the ocean-atmosphere system reflected as a prominent negative carbon isotope excursion (CIE) in sedimentary components. Earth's surface and deep ocean waters warmed by ~5 °C, of which part may have occurred prior to the CIE. However, few records document continental climatic trends and changes in seasonality have not been documented. Here we present the first high-resolution vegetation reconstructions for the PETM, based on bioclimatic analysis of terrestrially-derived spore and pollen assemblages preserved in an expanded section from the Central North Sea. Our data indicate reductions in boreal conifers and an increase in mesothermal to megathermal taxa, reflecting a shift towards wetter and warmer climate. We also record an increase in summer temperatures, greater in magnitude than the rise in mean annual temperature changes. Within the CIE, vegetation varies significantly with initial increases in epiphytic and climbing ferns, and development of extensive wetlands, followed by abundance of Carya spp. indicative of broadleaf forest colonization. Critically, the change in vegetation we report occurs prior to the CIE, and is concomitant with anomalous marine ecological change, as represented by the occurrence of Apectodinium augustum. This suggests that amplifications of seasonal extremes triggered carbon injection.

Citation: Eldrett, J. S., Greenwood, D. R., Polling, M., Brinkhuis, H., and Sluijs, A.: A seasonality trigger for carbon injection at the Paleocene-Eocene thermal maximum, Clim. Past Discuss., 9, 5837-5854, doi:10.5194/cpd-9-5837-2013, 2013.
Search CPD
Discussion Paper
Final Revised Paper