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| This fire-recovery pattern is similar to that seen in some parts of the world today. For example, after a forest fire in New England, ferns are often the pioneering plant that grows first. Many years are needed for birch forests, and eventually hardwood maple forests, to recover. |
| ATMOSPHERIC HEATING: Jay Melosh at the University of Arizona and several of his colleagues realized that the post-impact fires were produced when impact ejecta superheated the atmosphere. Some of the debris ejected from the Chicxulub crater rose above the Earth's atmosphere before it rained back down to Earth. The particles of material in the ejecta plume, just like falling meteors, heated the atmosphere. There was so much debris falling through the atmosphere at the same time, that it heated the atmosphere to far higher temperatures than individual meteors. A large fraction of this heat was radiated to the ground, raising surface temperatures to several hundreds of degrees and causing vegetation to burst into flames. |
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| New model calculations of these processes by David Kring (Univ. Arizona) and Daniel D. Durda (Southwest Research Institute) show how the fires were ignited, initially around the impact site and, soon afterwards, at a spot on the opposite side of the Earth where a concentrated stream of debris rained back down on Earth. As the Earth rotated below the impact ejecta, the fires spread to the west of these two locations over the following hours to days. Fires were ignited in North America, South America, Africa, and Asia. Depending on the trajectory of the impacting asteroid or comet, and details in the expanding plume of impact ejecta, fires may have also been ignited in Antarctica or Europe. |
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