The idea that dinosaurs survived for some time after the asteroid impact blamed for wiping them out 65 million years ago has been dealt a blow. Dinosaur egg fragments dug out of rocks in China seem to postdate the dramatic extinction event popularly believed to have extinguished the creatures. But new data suggests the egg pieces got mixed up in later deposits through the action of mud and debris flows. Details of the latest findings are published in the Journal of Geology.Dinosaurs survived until the end of the Cretaceous Period of Earth history. But by the beginning of the Tertiary Period, about 65 million years ago, they had apparently vanished. At numerous sites around the world, a clay layer separates rocks laid down in the Cretaceous from those deposited in the Tertiary. This is known as the K-T boundary. The boundary contains high concentrations of the element iridium, commonly found in meteorites. Researchers have proposed that a meteorite impact which produced a huge crater at Chicxulub in Mexico, could have been responsible for the demise of the creatures. Discoveries of dinosaur egg fragments in deposits from Nanxiong Basin, southern China, which contain Tertiary animal remains and pollen, suggested dinosaurs there could have survived until about 62 million years ago.
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