Persistent near-tropical warmth on the Antarctic continent during the early Eocene epoch

Contreras, L. et al. (2012) Persistent near-tropical warmth on the Antarctic continent during the early Eocene epoch. Nature, 488, pp. 73-77. (doi: 10.1038/nature11300) (PMID:22859204)

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Abstract

The warmest global climates of the past 65 million years occurred during the early Eocene epoch (about 55 to 48 million years ago), when the Equator-to-pole temperature gradients were much smaller than today1, 2 and atmospheric carbon dioxide levels were in excess of one thousand parts per million by volume3, 4. Recently the early Eocene has received considerable interest because it may provide insight into the response of Earth’s climate and biosphere to the high atmospheric carbon dioxide levels that are expected in the near future5 as a consequence of unabated anthropogenic carbon emissions4, 6. Climatic conditions of the early Eocene ‘greenhouse world’, however, are poorly constrained in critical regions, particularly Antarctica. Here we present a well-dated record of early Eocene climate on Antarctica from an ocean sediment core recovered off the Wilkes Land coast of East Antarctica. The information from biotic climate proxies (pollen and spores) and independent organic geochemical climate proxies (indices based on branched tetraether lipids) yields quantitative, seasonal temperature reconstructions for the early Eocene greenhouse world on Antarctica. We show that the climate in lowland settings along the Wilkes Land coast (at a palaeolatitude of about 70° south) supported the growth of highly diverse, near-tropical forests characterized by mesothermal to megathermal floral elements including palms and Bombacoideae. Notably, winters were extremely mild (warmer than 10 °C) and essentially frost-free despite polar darkness, which provides a critical new constraint for the validation of climate models and for understanding the response of high-latitude terrestrial ecosystems to increased carbon dioxide forcing.

Item Type:Articles (Letter)
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Bendle, Dr James
Authors: Contreras, L., Pross, J., Bijl, P.K., Greenwood, D.R., Bohaty, S.M., Bendle, J.A., Röhl, U., Tauxe, L., Raine, J.I., Huck, C.E., van de Flierdt, T., Jamieson, S.S.R., Stickley, C.E., van de Schootbrugge, B., Schouten, S., Escutia, C., and Brinkhuis, H.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Research Group:IODP Expedition 318 Scientists
Journal Name:Nature
Publisher:Nature Publishing Group
ISSN:1476-4687
ISSN (Online):1476-4687
Published Online:01 August 2012

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
547411A biomarker goldmine in Wilkes Land, Antarctica: nuggets from the Eocene Greenhouse in sediments from IODP Expedition 318 (BIGWIG).James BendleNatural Environment Research Council (NERC)NE/I00646X/1SCHOOL OF GEOGRAPHICAL & EARTH SCIENCES