Impact of global cooling on Early Cretaceous high pCO 2 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: 2021
• Subjects: Antarc*; Antarctica; Weddell Sea
• Online Access: https://hdl.handle.net/1983/39c72005-088d-4d4a-9077-0e1db211158f; https://research-information.bris.ac.uk/en/publications/39c72005-088d-4d4a-9077-0e1db211158f; https://doi.org/10.1038/s41467-021-25706-0; https://research-information.bris.ac.uk/ws/files/308946725/Full_text_PDF_final_published_version_.pdf; http://www.scopus.com/inward/record.url?scp=85114862842&partnerID=8YFLogxK

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 86 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 2 over a period of ~700 thousand years. Consistent with geologic evidence, this pCO 2 drop favoured the potential build-up of local polar ice.