Impact of global cooling on Early Cretaceous high pCO 2 world during the Weissert Event

• Published in: Nature communications Vol. 12; no. 1; p. 5411
• Main Authors: Cavalheiro, Liyenne, Wagner, Thomas, Steinig, Sebastian, Bottini, Cinzia, Dummann, Wolf, Esegbue, Onoriode, Gambacorta, Gabriele, Giraldo-Gómez, Victor, Farnsworth, Alexander, Flögel, Sascha, Hofmann, Peter, Lunt, Daniel J, Rethemeyer, Janet, Torricelli, Stefano, Erba, Elisabetta
• Format: Journal Article
• Language: English
• Published: England 13.09.2021
• ISSN: 2041-1723

The Weissert Event ~133 million years ago marked a profound global cooling that punctuated the Early Cretaceous greenhouse. We present modelling, high-resolution bulk organic carbon isotopes and chronostratigraphically calibrated sea surface temperature (SSTs) based on an organic paleothermometer (the TEX proxy), which capture the Weissert Event in the semi-enclosed Weddell Sea basin, offshore Antarctica (paleolatitude ~54 °S; paleowater depth ~500 meters). We document a ~3-4 °C drop in SST coinciding with the Weissert cold end, and converge the Weddell Sea data, climate simulations and available worldwide multi-proxy based temperature data towards one unifying solution providing a best-fit between all lines of evidence. The outcome confirms a 3.0 °C ( ±1.7 °C) global mean surface cooling across the Weissert Event, which translates into a ~40% drop in atmospheric pCO over a period of ~700 thousand years. Consistent with geologic evidence, this pCO drop favoured the potential build-up of local polar ice.