Chinese scientists have used an unconventional method of dinosaur egg dating to determine that a fossilized egg in central China is about 86 million years old. This breakthrough provides new insights into dinosaur reproduction and ancient environmental changes.
On September 30, researchers at the Hubei Institute of Geosciences announced that they applied carbonate uranium-lead (U-Pb) techniques to eggshell minerals from Qinglong Mountain in Shiyan City, Hubei Province. The method uses lasers to vaporize the minerals. Scientists then measure uranium and lead ratios, making dinosaur egg dating more precise than earlier methods.
Lead researcher Zhao Bi explained that the technique has previously dated Earth, lunar rocks, and cave formations. Using it on fragile dinosaur eggshells is unprecedented. Earlier studies relied on surrounding rock layers, which only gave approximate age ranges. Dinosaur egg dating now allows direct measurement of the fossils themselves.
The study, published in Frontiers in Earth Science, found that eggshell minerals from Qinglong Mountain formed between 87.65 and 84.17 million years ago. Zhao noted that this period coincided with global cooling after a long greenhouse climate since roughly 93 million years ago. The results suggest that dinosaurs laid eggs during this climatic transition.
Since the 1990s, paleontologists have uncovered more than 3,000 dinosaur egg fossils at Qinglong Mountain. The site now includes a national-level nature reserve and an on-site museum. Most eggs belong to Placoolithus tumiaolingensis, but researchers continue searching for new types each year.
The fossilized eggs in this study are flat, circular, and have thick, bi-layered shells. Scientists believe the method of dinosaur egg dating could also work for eggs from other sites or non-dinosaur carbonate fossils. This could provide broader insights into evolutionary timelines.
Experts emphasize the importance of this direct dating approach. Guntupalli Prasad, a paleontologist at the University of Delhi, said it reduces uncertainties and strengthens fossil research. Susannah Maidment from London’s Natural History Museum cautioned that burial changes could alter minerals and affect age estimates.
Zhao admitted the study is exploratory, sampling only one eggshell from a 15-meter-thick layer. Still, he stressed the findings are meaningful, as few of the world’s 200-plus dinosaur egg sites have been precisely dated.
He concluded that broader use of dinosaur egg dating could help reconstruct reproductive behavior, reveal ancient climates, and illuminate mysteries of dinosaur evolution and extinction.
