Temperate rainforests near the South Pole during peak Cretaceous warmth


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Johann.Klages [ at ] awi.de

Abstract

The mid-Cretaceous period was one of the warmest intervals of the past 140 million years, driven by atmospheric carbon dioxide levels of around 1,000 parts per million by volume. In the near absence of proximal geological records from south of the Antarctic Circle, it is disputed whether polar ice could exist under such environmental conditions. Here we use a sedimentary sequence recovered from the West Antarctic shelf—the southernmost Cretaceous record reported so far—and show that a temperate lowland rainforest environment existed at a palaeolatitude of about 82°S during the Turonian–Santonian age (92 to 83 million years ago). This record contains an intact 3-metre-long network of in situ fossil roots embedded in a mudstone matrix containing diverse pollen and spores. A climate model simulation shows that the reconstructed temperate climate at this high latitude requires a combination of both atmospheric carbon dioxide concentrations of 1,120–1,680 parts per million by volume and a vegetated land surface without major Antarctic glaciation, highlighting the important cooling effect exerted by ice albedo under high levels of atmospheric carbon dioxide.



Item Type
Conference (Invited talk)
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Primary Division
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Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
Invited lecture, 23 Apr 2020 - 23 Apr 2020, University of California Santa Barbara, California, USA.
Eprint ID
51802
Cite as
Klages, J. P. , Salzmann, U. , Bickert, T. , Hillenbrand, C. D. , Gohl, K. and PS104, S. S. P. (2020): Temperate rainforests near the South Pole during peak Cretaceous warmth , Invited lecture, University of California Santa Barbara, California, USA, 23 April 2020 - 23 April 2020 .


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