Resumen de Mineralogical, elemental and chemical composition of dinosaur bones from Teruel (Spain)

Luis de Luque Ripoll, Luis Alcalá Martínez, Luis Mampel, María Dolores Pesquero, Alberto Cobos Periáñez, Ainara Aberasturi Rodríguez, Paz Marzo, Ramiro Alloza Izquierdo

• A detailed study has been carried out on 25 samples of dinosaur bone fragments which come from 8 sites belonging to six stratigraphic units that span from the Tithonian (Upper Jurassic) to Albian (Lower Cretaceous) in the province of Teruel, Spain. The aim of the study is to further understand the mineralogical, elemental and chemical composition of the bones which come from different depositional environments and try to determine the processes which created this composition starting from the initial biogenic phosphate. A diversity of chemical compositions within the same sedimentary environment, within the same site and even within the same fossil is documented. This supports the idea that fossilization and postmortem diagenesis is not a homogeneous process. The compositions of bones varied widely in their proportions of francolite, dahllite and hydroxyapatite phosphates. The most common cement is calcite but the presence of unidentified iron oxides is also very frequent. Haematite or barite cements are found more rarely. The association between the authigenic minerals kaolinite and palygorskite provides information about the geochemical processes occurring in the microenvironment of fossilization, and the presence of iron oxides, pyrite or barite is informative of microbial activity. Furthermore, different sources for fossils from a same site can potentially be differentiated. In sum, a direct relationship between the mineralogy of the bone and cement composition and the sedimentary environment cannot be inferred.