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[dinosaur] Asteroid impact, not volcanism, caused end-Cretaceous dinosaur extinction (free pdf)




Ben Creisler
bcreisler@gmail.com

A new paper with free pdf:

Alfio Alessandro Chiarenza, Alexander Farnsworth, Philip D. Mannion, Daniel J. Lunt, Paul J. Valdes, Joanna V. Morgan, and Peter A. Allison (2020)
Asteroid impact, not volcanism, caused the end-Cretaceous dinosaur extinction
Proceedings of the National Academy of Sciences (advance online publication)
doi: https://doi.org/10.1073/pnas.2006087117
https://www.pnas.org/content/early/2020/06/23/2006087117

Free pdf:
https://www.pnas.org/content/pnas/early/2020/06/23/2006087117.full.pdf

Significance

We present a quantitative test of end-Cretaceous extinction scenarios and how these would have affected dinosaur habitats. Combining climate and ecological modeling tools, we demonstrate a substantial detrimental effect on dinosaur habitats caused by an impact winter scenario triggered by the Chicxulub asteroid. We were not able to obtain such an extinction state with several modeling scenarios of Deccan volcanism. We further show that the concomitant prolonged eruption of the Deccan traps might have acted as an ameliorating agent, buffering the negative effects on climate and global ecosystems that the asteroid impact produced at the CretaceousâPaleogene boundary.

Abstract

The Cretaceous/Paleogene mass extinction, 66 Ma, included the demise of non-avian dinosaurs. Intense debate has focused on the relative roles of Deccan volcanism and the Chicxulub asteroid impact as kill mechanisms for this event. Here, we combine fossil-occurrence data with paleoclimate and habitat suitability models to evaluate dinosaur habitability in the wake of various asteroid impact and Deccan volcanism scenarios. Asteroid impact models generate a prolonged cold winter that suppresses potential global dinosaur habitats. Conversely, long-term forcing from Deccan volcanism (carbon dioxide [CO2]-induced warming) leads to increased habitat suitability. Short-term (aerosol cooling) volcanism still allows equatorial habitability. These results support the asteroid impact as the main driver of the non-avian dinosaur extinction. By contrast, induced warming from volcanism mitigated the most extreme effects of asteroid impact, potentially reducing the extinction severity.

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News:

Asteroid impact, not volcanoes, made the Earth uninhabitable for dinosaurs

http://www.imperial.ac.uk/news/198595/asteroid-impact-volcanoes-made-earth-uninhabitable/

https://phys.org/news/2020-06-asteroid-impact-volcanoes-earth-uninhabitable.html

https://www.theguardian.com/science/2020/jun/29/dinosaurs-wiped-out-by-asteroid-not-volcanoes-researchers-say


Volcanoes may have helped life bounce back after dinosaur-killing asteroid strike

https://www.nationalgeographic.com/science/2020/06/volcanoes-helped-life-bounce-back-afterdinosaur-killing-asteroid/

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