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K-Pg impact fires did not cause plant extinctions (free pdf)

Ben Creisler

A new online paper that may be of interest.

Claire M. Belcher, Rory M. Hadden, Guillermo Rein, Joanna V. Morgan,
Natalia Artemieva, and Tamara Goldin (2015)
An experimental assessment of the ignition of forest fuels by the
thermal pulse generated by the Cretaceous–Palaeogene impact at
Journal of the Geological Society (advance online publication)

A large extraterrestrial body hit the Yucatán Peninsula at the end of
the Cretaceous period. Models suggest that a substantial amount of
thermal radiation was delivered to the Earth’s surface by the impact,
leading to the suggestion that it was capable of igniting extensive
wildfires and contributed to the end-Cretaceous extinctions. We have
reproduced in the laboratory the most intense impact-induced heat
fluxes estimated to have reached different points on the Earth’s
surface using a fire propagation apparatus and investigated the
ignition potential of forest fuels. The experiments indicate that dry
litter can ignite, but live fuels typically do not, suggesting that
any ignition caused by impact-induced thermal radiation would have
been strongly regional dependent. The intense, but short-lived, pulse
downrange and at proximal and intermediate distances from the impact
is insufficient to ignite live fuel. However, the less intense but
longer-lasting thermal pulse at distal locations may have ignited
areas of live fuels. Because plants and ecosystems are generally
resistant to single localized fire events, we conclude that any fires
ignited by impact-induced thermal radiation cannot be directly
responsible for plant extinctions, implying that heat stress is only
part of the end-Cretaceous story.

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