Cretaceous 'Pompeii' of China isn't what we thought

Two perfectly articulated skeletons of the sheep-size dinosaur Psittacosaurus, found in China's Yixian Formation. New research suggests they died in burrow collapses, not via volcanism, as previously thought.

For decades, the Yixian Formation was known as the "Pompeii" of the dinosaur world. Anan early Cretaceous formation in northeast China, it holds some of the best preserved fossils on Earth and is a treasure trove for paleontologists that provides a snapshot into life 130 million to 120 million years ago.

Researchers believed that the formation's fossils were preserved by the ash deposited from volcanic eruptions, similar to how Mount Vesuvius covered the city of Pompeii in 19 feet (6 meters) of ash in 79 AD.