Overview
- Scientists directly dated eggshell carbonates with a micro‑laser uranium–lead method, analyzing vaporized material by mass spectrometry.
- The dated fossils are a clutch of 28 eggs from the Qinglongshan site in central China, yielding a Late Cretaceous age of roughly 85–86 million years with about ±1.7 million years uncertainty.
- These results provide the first reliable absolute ages for fossils at China’s first national dinosaur egg reserve, which preserves more than 3,000 eggs across three sites.
- Most eggs at the site are attributed to Placoolithus tumiaolingensis in the Dendroolithidae family, whose highly porous shells are hypothesized to reflect adaptation to cooler conditions.
- The team plans to sample eggs from additional layers and nearby basins to build regional timelines and test ideas about dinosaur ecology and movements.