Trace Element Determination of Late Cretaceous Dinosaur Eggshell Fossils from Xixia Basin, Henan Province by ICP-OES and Its Implications for Extinction of Dinosaurs

Dinosaur egg fossils are important for exploring the survival and extinction of the dinosaurs. Current researches on dinosaur egg fossils are concentrated in their biology and burial features. In this study, Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) was used to determine trace element composition of twelve dinosaur eggshell fossils in the late Cretaceous from Xixia basin and their surrounding rocks, in order to the relationship between trace elements and the extinction of dinosaurs. Results show that the dinosaur eggshell fossils are depleted in organic elements such as C, N, P and S, and mainly consist of essential elements such as Ca, Al, Mg, Fe and K and other trace elements such as Sr, Mn, Ba, La, Zn, B, V, Co and Ir. Abnormal high Ir and Sr may be related to the extraterrestrial impact event causing the dramatic changes of the ecological environment. Element assemblages indicated that the climate during the late Cretaceous in this area might have been semiarid to arid. Abnormal high Ir and Sr in the environment probably have caused structure and pathological changes of those eggs within the dinosaurs. Thereby the dinosaur eggs could not be hatched, which probably resulted in the gradual demise of dinosaurs. This study provides an important basis for investigating the living environment of dinosaurs, causes of extinction and the late Cretaceous climate.