Impact of global cooling on Early Cretaceous high pCO<sub>2</sub> world during the Weissert Event.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34518550.
- Also identified by DOI 10.1038/s41467-021-25706-0 and PMC identifier 8437947.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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<sub>86</sub> 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<sub>2</sub> over a period of ~700 thousand years. Consistent with geologic evidence, this pCO<sub>2</sub> drop favoured the potential build-up of local polar ice.