Impact mechanics of the Cretaceous-Tertiary extinction bolide

On Earth impact of ~ 10 km diameter, asteroidal or cometary objects the vaporized, melted and (< 1 mm) solid ejecta transfer ~40–50% of their energy to the atmosphere, giving rise to a short possibly lethal (to large animals) heating pulse. Some 1–20 projectile masses of early, high-speed and highly shocked (diameter, <1 µm) extraterrestrial-rich ejecta is lofted to altitudes of 10 km where it can be globally distributed. It is proposed that this material represents the global Cretaceous–Tertiary boundary layer. When in the upper atmosphere it may have caused decreases in solar tropospheric insolation and resulting major extinctions in biota.