1. Temperate rainforests near the South Pole during peak Cretaceous warmth
- Author
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Klages, J.P., Salzmann, U., Bickert, T., Hillenbrand, C.-D., Gohl, K., Kuhn, G., Bohaty, S.M., Titschack, J., Müller, J., Frederichs, T., Bauersachs, T., Ehrmann, W., van de Flierdt, T., Pereira, P.S., Larter, R.D., Lohmann, G., Niezgodzki, I., Uenzelmann-Neben, G., Zundel, M., Spiegel, C., Mark, C., Chew, D., Francis, J.E., Nehrke, G., Schwarz, F., Smith, J.A., Freudenthal, T., Esper, O., Pälike, H., Ronge, T.A., Dziadek, R., Afanasyeva, V., Arndt, J.E., Ebermann, B., Gebhardt, C., Hochmuth, K., Küssner, K., Najman, Y., Riefstahl, F., Scheinert, M., PS104, the Science Team of Expedition, and Natural Environment Research Council (NERC) more...
- Subjects
Spores ,Geologic Sediments ,Rainforest ,010504 meteorology & atmospheric sciences ,General Science & Technology ,Climate ,WEST ANTARCTICA ,Antarctic ice sheet ,Antarctic Regions ,F800 ,ANTARCTIC ICE-SHEET ,010502 geochemistry & geophysics ,BOUNDARY-CONDITIONS ,01 natural sciences ,Science Team of Expedition PS104 ,Temperate climate ,JAMES-ROSS-ISLAND ,Glacial period ,History, Ancient ,0105 earth and related environmental sciences ,Carbon dioxide in Earth's atmosphere ,Multidisciplinary ,Science & Technology ,Atmosphere ,Fossils ,AMUNDSEN SEA EMBAYMENT ,Temperature ,COEXISTENCE APPROACH ,Carbon Dioxide ,Models, Theoretical ,Cretaceous ,Multidisciplinary Sciences ,HETEROCYST GLYCOLIPIDS ,Science & Technology - Other Topics ,PROXY DATA ,Pollen ,Climate model ,Physical geography ,Temperate rainforest ,MARIE BYRD LAND ,Geology ,New Zealand - Abstract
The mid-Cretaceous period was one of the warmest intervals of the past 140 million years1–5, driven by atmospheric carbon dioxide levels of around 1,000 parts per million by volume6. 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. Multi-proxy core data and model simulations support the presence of temperate rainforests near the South Pole during mid-Cretaceous warmth, indicating very high CO2 levels and the absence of Antarctic ice. more...
- Published
- 2020