The asteroid with a diameter of about ten kilometres that created the Chicxulub crater most probably caused the worldwide extinction of species at the boundary between the Cretaceous and the Palaeogene. The event caused the extinction of about 75 percent of all species. Its effect was due mainly to the fact that it impacted into rocks rich in carbonate and anhydrite. This hurled massive amounts of carbon dioxide (CO2) and sulphur dioxide (SO2) into the atmosphere. It is estimated that between 200 and 3000 cubic kilometres of sediments vaporised, releasing 35 to 700 million tons of sulphur and 10 billion tons of CO2 into the atmosphere. The ozone layer would probably have been destroyed within a very short time, and there must have been complete darkness over the Earth for months due to the dust in the atmosphere. This had serious short- and long-term consequences for the climate and biosphere. The crater that remains has a diameter of 180 kilometres and extends from the Yucatán peninsula to the Gulf of Mexico.
In http://www.sciencedaily.com/releases/2009/09/090911210024.htm
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