The sulfur cloud from the asteroid impact blocked out the Sun and caused a 'global winter' that lasted more than a decade.
Notes on verification
Confirmed by multiple peer-reviewed studies (PNAS, Nature Geoscience) and research institution summaries showing sulfur/soot-driven impact winter lasting years to over a decade following the Chicxulub asteroid impact.
Sources
- 30 Seconds May Have Made All the Difference for Dinosaurs | HISTORY (history.com)
- https://www.pnas.org/doi/full/10.1073/pnas.2119194119 (pnas.org)
- https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/25079/Junium_2022_PNAS_Massiveperturbations_CC.pdf?sequence=1 (research-repository.st-andrews.ac.uk)
- https://www.nature.com/articles/s41561-023-01290-4 (nature.com)
- https://www.pik-potsdam.de/en/news/latest-news/how-the-darkness-and-the-cold-killed-the-dinosaurs (pik-potsdam.de)
- https://www.gi.alaska.edu/news/first-day-dinosaur-extinction (gi.alaska.edu)