Summary
Researchers analyzed lignite samples from the Western Interior of the United States to reconstruct mean annual air temperatures (MAATs) leading up to the Cretaceous-Paleogene (K-Pg) boundary. They found a long-term warming trend of ~3°C over the last 100 kyr of the Cretaceous, followed by a transient cooling event of 2-5°C, coinciding with the peak of the Poladpur "pulse" of Deccan eruption ~30 kyr before the K-Pg boundary.
Highlights
- Reconstructed MAATs using the MBT'5me proxy calibration developed for peats.
- Found a long-term warming trend of ~3°C over the last 100 kyr of the Cretaceous.
- Identified a transient cooling event of 2-5°C, coinciding with the peak of the Poladpur "pulse" of Deccan eruption.
- The cooling event was likely caused by the aerosolization of volcanogenic sulfur.
- Temperatures returned to pre-event values before the mass extinction.
- The study suggests that volcanogenic climate change was not the primary cause of K-Pg extinction.
- The findings support both models of climate change induced by Deccan volcanism.
Key Insights
- The study provides the first terrestrial evidence for a transient cooling event linked to Deccan volcanism, which was previously recognized in marine records.
- The cooling event was likely caused by the conversion of volcanogenic sulfur into sulfate aerosols, which would have reflected sunlight and cooled the planet.
- The long-term warming trend of ~3°C over the last 100 kyr of the Cretaceous was likely driven by Deccan CO2 emissions.
- The study highlights the varying tempo of Deccan volcanism-induced climate change, with both longer-term warming and shorter-term cooling events.
- The findings suggest that the primary cause of the K-Pg extinction was not volcanogenic climate change, but rather another factor, such as the Chicxulub meteorite impact.
- The study emphasizes the utility of lignite and coal records as sensitive archives of deep-time terrestrial climate change.
- The research provides a new perspective on the role of Deccan volcanism in shaping the Earth's climate and ecosystems during the Cretaceous-Paleogene transition.
Mindmap
Citation
O’Connor, L. K., Jerrett, R. M., Price, G. D., Lyson, T. R., Lengger, S. K., Peterse, F., & van Dongen, B. E. (2024). Terrestrial evidence for volcanogenic sulfate-driven cooling event ~30 kyr before the Cretaceous–Paleogene mass extinction. In Science Advances (Vol. 10, Issue 51). American Association for the Advancement of Science (AAAS). https://doi.org/10.1126/sciadv.ado5478