Overview

• Using carbonate U–Pb analysis via LA‑MC‑ICP‑MS, researchers dated eggshell and infill calcite from a Qinglongshan clutch to a depositional age of 85.91 million years with an uncertainty of about ±1.7 million years.
• The study reports the first in‑situ isotopic ages for dinosaur eggshells, resolving a long‑standing age gap at China’s Qinglongshan egg reserve.
• Eggshell calcite yielded more consistent results than the calcite infill initially targeted, a finding the team says was unexpected and important for future sampling.
• Independent paleontologists welcomed the advance but cautioned that diagenetic alteration must be ruled out to ensure accuracy, prompting calls for further mineralogical checks.
• The dated material comes from a cluster of 28 eggs at a site holding more than 3,000 largely in‑situ eggs, and the authors plan broader sampling to build regional and global timelines linking nests to Cretaceous climate shifts.