Dandy wrote:
Everytime there is a report in the media about the exstinction of the dinos, the impact of an asteroid on the Yucatan peninsula in Mexico is quoted as the reason.
Given the size of Yucatan I always doubted that an impact there could cause an worldwide mass destinction.
It was what was hit, rather than the size of the impact, there have been larger impacts.
The Yucatan, where the giant asteroid hit, was especially rich in sulfur and Limestone (calcium sulfate). The impact vaporized the sulfate and deposited billions of tons of sulfur dioxide gas, carbolic acid, and hydrogen sulfide into the atmosphere.
Volcanic eruptions show that sulfur dioxide gas would convert to sulfuric acid clouds in the atmosphere, and that such clouds could remain in the atmosphere for years. These clouds may have initially been thick enough to shut down photosynthesis for a year, and perhaps longer.
Meteorite impact and the mass extinction of species at the Cretaceous/Tertiary boundary
A key aspect of the Yucatan site is that the upper 3 km of rock were rich in water, carbonate, and sulfate, which upon impact produced about 200 gigatons each of SO2 and H2O vapor and other gases that greatly altered the properties of the stratosphere.
