Terrestrial cooling in Northern Europe during the Eocene–Oligocene transition
| Autor: | Margaret E. Collinson, Kyger C. Lohmann, Melanie J. Bugler, Michael T. Hren, Nathan D. Sheldon, Jerry J. Hooker, Stephen T. Grimes |
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| Rok vydání: | 2013 |
| Předmět: |
Climate
Climate Change Gastropoda Antarctic Regions Climate change Paleontology Paleoclimatology Animals Glacial period geography Carbon dioxide in Earth's atmosphere Multidisciplinary geography.geographical_feature_category Atmosphere Fossils Ice Temperature Northern Hemisphere Water Geology Carbon Dioxide Models Theoretical United Kingdom Europe Sea surface temperature Oceanography Physical Sciences Deep ocean water Ice sheet |
| Zdroj: | Proceedings of the National Academy of Sciences. 110:7562-7567 |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | Geochemical and modeling studies suggest that the transition from the “greenhouse” state of the Late Eocene to the “icehouse” conditions of the Oligocene 34–33.5 Ma was triggered by a reduction of atmospheric p CO 2 that enabled the rapid buildup of a permanent ice sheet on the Antarctic continent. Marine records show that the drop in p CO 2 during this interval was accompanied by a significant decline in high-latitude sea surface and deep ocean temperature and enhanced seasonality in middle and high latitudes. However, terrestrial records of this climate transition show heterogeneous responses to changing p CO 2 and ocean temperatures, with some records showing a significant time lag in the temperature response to declining p CO 2 . We measured the Δ 47 of aragonite shells of the freshwater gastropod Viviparus lentus from the Solent Group, Hampshire Basin, United Kingdom, to reconstruct terrestrial temperature and hydrologic change in the North Atlantic region during the Eocene–Oligocene transition. Our data show a decrease in growing-season surface water temperatures (∼10 °C) during the Eocene–Oligocene transition, corresponding to an average decrease in mean annual air temperature of ∼4–6 °C from the Late Eocene to Early Oligocene. The magnitude of cooling is similar to observed decreases in North Atlantic sea surface temperature over this interval and occurs during major glacial expansion. This suggests a close linkage between atmospheric carbon dioxide concentrations, Northern Hemisphere temperature, and expansion of the Antarctic ice sheets. |
| Databáze: | OpenAIRE |
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