A fossil site in China that has given up thousands of stunningly well-preserved specimens to paleontologists since the 1920s was the Pompeii of the early Cretaceous.
Millions of years ago, birds, dinosaurs and small mammals that lived in this north-eastern region of China were caught off guard by eruptions from nearby volcanoes. A scorching flood of hot rocks and ash petrified them and transported the carcasses into low-lying volcanic lakes, where they remained until humans unearthed them eons later, a new study suggests.
Given the abundance of volcanic rocks in the area, scientists have suspected that volcanic activity had a hand in preserving the specimens. But the new work, published in the Tuesday issue of Nature Communications, is the first to make a case for the flows killing and transporting the animals.
"That’s quite a radical, new idea," Mike Benton, a paleontologist at the University of Bristol, wrote to NBC News in an email, and "quite a challenge" to the previously theories that indicated that rivers, and not volcanic runoff, carried the animals into the lakes.
From fossils extracted from five locations from the region, now known as the Jehol biota, researchers identified scorched tissue, and "re-crystallized" sections of bone on fossils. Both were indications that the animals had been exposed to intense heat, Baoyu Jiang, a paleontologist at Nanjing University, and author on the new study told NBC News.
Though famous fish fossils have emerged from the region, only terrestrial fossils — birds, lizards, mammals — showed marks of transport by these volcanic pyroclastic flows, at least so far, he said.
Benton, who was not involved with the new study, said that the "basis of the work is good," but it's "unlikely" that the flows transported the animals. "At Pompeii, people were overwhelmed and killed, but not transported," and it's likely that's what happened to the dinosaurs too.