Cause of end-Cretaceous dinosaur extinction

A study suggests that an asteroid impact, not volcanic activity, was the main cause of dinosaur extinction. Nonavian dinosaurs went extinct during the end-Cretaceous mass extinction, 66 million years ago, which coincided with both the Chicxulub asteroid impact and heightened volcanic activity in the Deccan Traps. The relative contribution of the two environmental perturbations to the mass extinction is a subject of debate. Alessandro Chiarenza and colleagues modeled the climatic perturbations caused by the two potential extinction drivers at the end of the Cretaceous period as well as their effects on dinosaur habitat suitability. The analysis found that a reduction in sunlight of 10-15% caused by an asteroid impact resulted in global cooling that would have virtually eliminated suitable dinosaur habitat worldwide. Heightened volcanism would have led to a much smaller reduction in sunlight that would likely have been insufficient to cause complete extinction by itself. Heightened volcanism would have also increased atmospheric CO2, leading to global warming and an increase in dinosaur habitat suitability over the long term. Simulations combining an asteroid impact and heightened volcanism exhibited accelerated postimpact climate recovery, compared with an impact in the absence of volcanism. The results suggest that the asteroid impact, not heightened volcanism, was the main driver of nonavian dinosaur extinction and that volcanically induced warming might have instead mitigated the effects of the impact, according to the authors.

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Article #20-06087: “Asteroid impact, not volcanism, caused the end-Cretaceous dinosaur extinction,” by Alfio Alessandro Chiarenza, Alexander Farnsworth et al.

MEDIA CONTACT: Alfio Alessandro Chiarenza, Imperial College London, UNITED KINGDOM; tel: 469-426-9229, +39 329 238 7726; e-mail:

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; Alex Farnsworth, University of Bristol, UNITED KINGDOM; tel: +44-117-331-8352; e-mail:

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; Philip Mannion, University College London, UNITED KINGDOM; tel: +44-20-3108-8208; e-mail:

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