Impact of global cooling on Early Cretaceous high pCO2 world during the Weissert Event
Liyenne Cavalheiro, Thomas Wagner, Sebastian Steinig, Cinzia Bottini, Wolf Dummann, Onoriode Esegbue, Gabriele Gambacorta, Victor M. Giraldo-Gómez, Alexander Farnsworth, Sascha Flögel, Peter Hofmann, Daniel J. Lunt, Janet Rethemeyer, Stefano Torricelli, Elisabetta Erba
Abstract
Abstract 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 p CO 2 over a period of ~700 thousand years. Consistent with geologic evidence, this p CO 2 drop favoured the potential build-up of local polar ice.