Two complete skeletons of the dinosaur Psittacosaurus from one of the sites analyzed by the research team. Some scientists say these fossils show evidence of preservation due to their burrows collapsing.
NPS has news of an interesting new theory of how a group of dinosaurs were preserved in China. Recent research offers a new perspective on the preservation of dinosaur fossils in China's Yixian Formation, often dubbed the "Chinese Pompeii." Previously, the exceptional preservation of these Cretaceous-period fossils was attributed to periodic volcanic eruptions over a 90,000-year span. However, a study published in the Proceedings of the National Academy of Sciences (PNAS) challenges this view. Paul Olsen of Columbia University proposes that many of these dinosaurs perished due to the collapse of their burrows, leading to suffocation. This theory suggests that rather than catastrophic volcanic events, more mundane processes like burrow collapses played a significant role in the fossilization of these ancient creatures.
Olsen and his colleagues studied the sediment surrounding and inside two three-dimensional fossils of Psittacosaurus. “The sediment inside the animal in both dinosaurs was much finer grained than the sediment outside of it,” he says.
That observation indicated to Olsen that the animals were buried with their skin and muscles still intact, since the flesh would have only allowed fine grained material to flow slowly into the body cavity, filtering out anything coarse. Olsen and his collaborators argue that such a burial would not have been the result of catastrophic volcanic flows. He says burrow collapse is a more straightforward conclusion.
“Maybe some of them collapsed because a big sauropod dinosaur walked by,” says Olsen. “Or maybe it was an earthquake. Or maybe it was just the water-logged mud simply collapsed.”
