[Characterization of dinosaur fossils and their surrounding rocks by atomic emission spectrometry and X-ray powder diffractometry].

More dinosaur fossils have been found in the Laochangqing valley, Lufeng county than anywhere else in the world, and the dinosaur fossils found here cover the longest time span (including the early and middle Jurassic ages). This excavation offers an ideal experimental base for prehistoric biology studies. This paper presents an elementary analysis of the components and structure of the dinosaur fossils in three different geologic-layers and their surrounding rocks in the above mentioned area. Atomic emission spectrum shows that the fossils are rich in the contents of calcium (>5%) and phosphor, but low in the content of silicon (3%-8%), while the surrounding rocks are high in the content of silicon (>10%). Furthermore, XRD results show that the major compound of the fossils is CaCO3 (66%), followed by SiO2 (17%); while that of the surrounding rocks is SiO2 (>80%), followed by CaCO3 (<12%). The most important difference between the fossils and the surrounding rocks is, according to the experiment, that phosphate has been identified in the former but not in the latter. This is a characteristic that can be used to distinguish the dinosaur fossils from other rocks. This paper provides valuable data for further zoological studies on the living conditions and evolution of the dinosaurs in the Laochangqing valley, Lufeng county.