Effects of the K-P Firestorms

Analysis of the recovery from the K-P mass extinction should begin with a clear understanding of the conditions at the start of the recovery. Numerical modeling of the Chicxulub impact shows that re-entrant ejecta carried about 20,000,000 megatons of kinetic energy around the globe. This is roughly equivalent to one-megaton hydrogen bombs being detonated at six-kilometer intervals around the entire planet. This kinetic energy was converted to heat when the ejecta re-entered the atmosphere, and much of this heat was conveyed to the Earth's surface by infrared radiation. The radiation was intense enough to ignite continental-scale firestorms that burned with blast-furnace intensity for several hours, reducing the entire unsheltered biomass to ash. All of the terrestrial survivors were sheltered from this heat and fire either underground or in water. This theoretical model is supported by the following evidence: 1) A global 3-mm layer of re-entrant spherules which, at sub-orbital speeds, carried a quantity of kinetic energy consistent with the numerical models; 2) no fossil evidence of survivors in the early Paleocene other than those that were plausibly sheltered in burrows or in water. 3) the observed soot in the K-P boundary sediments in Europe and New Zealand; 4) the observed absence of charcoal in the K-P sediments: Charcoal would have burned in the extraordinarily high temperatures of a continental-scale firestorm, and the source of additional charcoal would have been removed for decades to centuries until earliest Paleocene forests grew back from buried roots and seeds to the point they could experience forest fires once again. Finally, uncharred plant matter observed in the K-P sediments was sheltered by water. No simple explanation other than IR radiation and firestorms has been proposed that is similarly consistent with all the available K-P data and modeling results.