The Chinese Pompeii? Death and destruction of dinosaurs in the Early Cretaceous of Lujiatun, NE China

- We present a systematic description of the sedimentology of the Lujiatun Unit.
- Our data show multiple fossiliferous horizons within the Lujiatun Unit.
- Most Lujiatun fossils originate from remobilised volcaniclastic sediments.
- Burial events are not necessarily associated with volcanic eruptions.
- Our results provide a basis for understanding the taphonomy of Lujiatun fossils.

The Lujiatun Unit (Yixian Formation) yields some of the most spectacular vertebrate fossils of the Jehol Group (Lower Cretaceous) of NE China. Specimens are preserved both articulated and three-dimensional, unlike the majority of Jehol fossils, which are near two-dimensional compression fossils. The site has been referred to as the 'Chinese Pompeii' because the dinosaurs and other animals were assumed to have been killed and buried by hot, airborne volcanic debris and ash in a single event; this has yet to be confirmed. Field and laboratory evidence for the sedimentological context of the fossils from the Lujiatun Unit is described in detail, and used to assess whether the fossil remains correspond to a single depositional event and whether this event was the direct result of volcanic activity. Fossils of the Lujiatun Unit occur in several horizons of volcaniclastic sediments that represent multiple depositional events. Petrological analysis shows that the fossil-bearing sediments were remobilised and deposited by water. The Lujiatun dinosaurs and other fossils were therefore not killed by a single airborne volcanic ash, but in multiple flood events with a high load of volcaniclastic debris.