Study Says 66-Million-Year Asteroid Triggered 3.5-Fold Stronger Firestorms

3 articles · Updated · Space.com · Aug 1

A new JGR Biogeosciences study says the Chicxulub impact’s first hours may have been deadlier than thought, with a dust-amplified heat pulse potentially killing most exposed land animals within one to two hours.
The mechanism was a fine silicate dust layer formed from vaporized rock: acting like an insulating blanket, it redirected thermal radiation back to Earth and made surface heating about 3.5 times stronger than spherule-only models.
Researchers estimate exposed terrestrial animals received roughly 17 times the thermal dose lethal to humans, while the heat exceeded ignition thresholds for grass, lichen and pine needles that could have spread larger fires.
Evidence for the dust layer comes from Tanis in North Dakota and the Raton Basin on the Colorado-New Mexico border, but direct wildfire evidence for this inferno scenario has so far been found only in North America.
The same dust could also explain the years-long impact winter that followed, linking an immediate global burn phase with the longer darkness and cooling long blamed for the dinosaurs’ extinction.