Cold spells in the Nordic Seas during the early Eocene Greenhouse

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 o...

Full description

Bibliographic Details
Published in:Nature Communications
Main Authors: Vickers, Madeleine L., Lengger, Sabine K., Bernasconi, Stefano M., Thibault, Nicolas, Schultz, Bo Pagh, Fernandez, Alvaro, Ullmann, Clemens V., McCormack, Paul, Bjerrum, Christian J., Rasmussen, Jan Audun, Hougård, Iben Winther, Korte, Christoph
Format: Text
Language:English
Published: Nature Publishing Group UK 2020
Subjects:
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7501286/
http://www.ncbi.nlm.nih.gov/pubmed/32948769
https://doi.org/10.1038/s41467-020-18558-7
Description
Summary: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.