The dinosaurs were wiped out as the result of a single gigantic asteroid and not by a series of multiple impacts according to researchers from the University of Missouri-Columbia led by Professor Ken MacLeod.
The research team believe that a piece of rock about 10 km wide hit Mexico’s Yucatan Peninsula and created the Chicxulub crater measuring 180 km across 65.5 million years ago. The impact would of caused earthquakes and tsunamis, sparked global fires and spewed enormous amounts of rock and dust into the atmosphere blocking the sun for years.
However researchers from Princeton University believe in a competing theory that the Chicxulub crater is not the cause of the mass extinctions and predates the end of the dinosaurs by 300,000 years. The Princeton group believe that one or more other chunks of rock came along at a later date and that their impact craters have not as yet been found.
MacLeod’s team believe that the single impact theory is supported by their latest research in which they examined sediment taken from drill sites deep below the sea surface about 4,500 km from the Yucatan impact site. The samples that they examined contained a layer of impact related material but no other evidence of impact above or below that layer indicating, they believe, that there were no other impacts.

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