Dinosaur eggs from China found to be around 86 million years old, according to ‘atomic clock’ dating

Researchers collected and vaporized samples from fossilized eggshells in China's Qinglongshan fossil reserve. They calculated how old the eggs were by measuring accumulated lead and uranium atoms in the samples Bi Zhao

A clutch of 28 dinosaur eggs found in the Qinglongshan fossil reserve in central China is about 86 million years old, according to scientists who used an “atomic clock” method to date the samples. Researchers said they now hope the eggs, and the technique employed to evaluate their age, might help to reveal how dinosaurs living in China’s Yunyang Basin adapted to a cooling climate.

The dating technique used on the eggs, known more formally as carbonate uranium-lead, or U-Pb, dating, is a common process for determining the age of carbonate minerals — those containing ca