Cold spells in the Nordic Seas during the early Eocene Greenhouse.

Autor:	Vickers ML; IGN, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark. mlv@ign.ku.dk., Lengger SK; Biogeochemistry Research Centre, School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK., Bernasconi SM; ETH Zurich, Geologisches Institut, Sonneggstrasse 5, 8092, Zürich, Switzerland., Thibault N; IGN, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark., Schultz BP; Museum Salling, Fur Museum, Nederby 28, 7884, Fur, Denmark., Fernandez A; Bjerknes Centre for Climate Research and Department of Earth Science, University of Bergen, Allégaten 41, N-5007, Bergen, Norway., Ullmann CV; Camborne School of Mines, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, UK., McCormack P; Biogeochemistry Research Centre, School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK., Bjerrum CJ; IGN, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark., Rasmussen JA; Museum Mors, Fossil- and Mo-clay Museum, Skarrehagevej 8, 7900, Nykøbing Mors, Denmark., Hougård IW; IGN, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark., Korte C; IGN, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.
Jazyk:	angličtina
Zdroj:	Nature communications [Nat Commun] 2020 Sep 18; Vol. 11 (1), pp. 4713. Date of Electronic Publication: 2020 Sep 18.
DOI:	10.1038/s41467-020-18558-7
Abstrakt:	The early Eocene (c. 56 - 48 million years ago) experienced some of the highest global temperatures in Earth's history since the Mesozoic, with no polar ice. Reports of contradictory ice-rafted erratics and cold water glendonites in the higher latitudes have been largely dismissed due to ambiguity of the significance of these purported cold-climate indicators. Here we apply clumped isotope paleothermometry to a traditionally qualitative abiotic proxy, glendonite calcite, to generate quantitative temperature estimates for northern mid-latitude bottom waters. Our data show that the glendonites of the Danish Basin formed in waters below 5 °C, at water depths of <300 m. Such near-freezing temperatures have not previously been reconstructed from proxy data for anywhere on the early Eocene Earth, and these data therefore suggest that regionalised cool episodes punctuated the background warmth of the early Eocene, likely linked to eruptive phases of the North Atlantic Igneous Province.
Databáze:	MEDLINE
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