Dinosaurs were found frozen mid-sleep after a prehistoric catastrophic ash burial similar to Pompeii

The serenity of the afternoon in a beautiful prehistoric forest was abruptly interrupted by the deafening sound of the earth roaring with fury. In the heart of what is today northeastern China, there occurred a gigantic volcanic eruption that produced an infernal mass of ash, gas and burning rocks, which engulfed everything it touched in its wake. For hundreds of years, the doomed city of Pompeii in Italy remained the classic example of the devastating fury of nature.Today, however, palaeontologists are uncovering a far older, Mesozoic version of this same tragedy, revealing that millions of years before humans walked the Earth, several dinosaur communities were entombed instantly by volcanic ash in their final, ordinary moments of life.These fascinating facts have been extracted from the rich fossil layers belonging to the Yixian Formation located in Liaoning Province. In addition to its technical name, the 'Jehol Biota', this unusual site has acquired the rather unsettling reputation of being known as the Chinese Pompeii. While regular fossil finds are normally represented by fragments of bones spread around an excavation site, findings in the Jehol Biota consist of fully formed and well-preserved skeletons retrieved straight from the rock layers. What stands out most in this discovery is the realistic position of the animals frozen in time – in many cases, they seem to be simply catching some shut-eye through the storm.The physics of prehistoric preservationExactly how such incredible preservation occurs has always been at the heart of scientific debates on the subject. One groundbreaking paper published in the peer-reviewed journal Nature Communications provided a revealing analysis of this unusual setting. This research team focused their attention on studying the volcanic deposits containing the bodies of prehistoric creatures to reveal the physics behind the preservation process.The findings from this study correspond to those of similar geological investigations, such as those found in the journal Palaeogeography, Palaeoclimatology, Palaeoecology. It is through the meticulous petrological mapping of the sediment layers that geologists have been able to determine that it was the rapidly moving density currents of finely powdered volcanic rocks (known as pyroclastic density currents) that overwhelmed the organisms.A series of quick geological events in the Early Cretaceous period saw intense flows of hot ash and debris cover the rivers and lakes, trapping the dinosaurs in pockets of earth without air and before any scavengers or natural forces could destroy their remains. The immediate trapping was a form of perfect geological preservation that helped the remains retain their articulations intact without being damaged by the pressure of tectonic movement throughout hundreds of millions of years that followed. Frozen behaviour patterns in the false hushThe wide diversity of creatures trapped in this early volcanic event allows for unique insight into the behavioural traits of Early Cretaceous life forms. One of the most frequently uncovered victims of this event is Psittacosaurus, a small and dog-sized horned dinosaur that moved around in herds in the thick bushes of the time. Scientists have recovered complete family groups of Psittacosaurus locked in clusters, indicating that these creatures used to group themselves for protection or social interaction in the closing volcanic atmosphere.Far more moving is the find of small, bird-like theropods, such as Mei long, an animal whose name directly means “sleeping dragon.” This fragile little dinosaur was discovered perfectly preserved, with its lengthy tail curled up around its body, and its head positioned under its front limb, mirroring the precise position that can be seen in birds today when they sleep. Previously, it was thought that these dinosaurs had died from malnutrition or illness, but the geology proves otherwise. The lethal flows of volcanic ash were so swift and silent that the sleeping dragon never got the chance to wake up.As more research is conducted by international teams on the minute pieces of the Jehol Biota, it becomes increasingly clear that the lesson learned is one of immense gratitude for the fortunate circumstances surrounding palaeontological discoveries. As violent volcanic eruptions usually result in mass deaths with only ashes remaining afterwards, this particular incident happened to be a natural time capsule. By capturing the creatures as they slept and showcasing their natural interactions through fossils, the Chinese ash fields were able to remove any clinical detachment found within fossilised remains and present a vividly lifelike glimpse of a beautiful past.