Impact of global cooling on Early Cretaceous high pCO2 world during the Weissert Event

• Published in: Nature Communications
• 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: Article in Journal/Newspaper
• Language: English
• Published: Nature Research 2021
• Subjects: Weddell; Weddell Sea; Antarc*; Antarctica
• Online Access: https://oceanrep.geomar.de/id/eprint/54156/; https://oceanrep.geomar.de/id/eprint/54156/1/s41467-021-25706-0.pdf; https://oceanrep.geomar.de/id/eprint/54156/2/41467_2021_25706_MOESM3_ESM.xlsx; https://oceanrep.geomar.de/id/eprint/54156/8/41467_2021_25706_MOESM1_ESM.pdf; https://doi.org/10.1038/s41467-021-25706-0

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 TEX86 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 pCO2 over a period of ~700 thousand years. Consistent with geologic evidence, this pCO2 drop favoured the potential build-up of local polar ice.