RARE EARTH ELEMENT GEOCHEMISTRY OF VERTEBRATE FOSSILS FROM THE CRETACEOUS MORENO FORMATION, CALIFORNIA

The Cretaceous Moreno Formation of California contains remains of marine reptiles such as plesiosaurs, mosasaurs, and even some dinosaurs (hadrosaurs) that have floated into the marine environment. The goal of this study is to examine the rare earth element (REE) concentrations of bone fragments from these vertebrate remains in order to finger-print bones from the formation, address taphonomy, and interpret the depositional environment. The bones will be cleaned of sediment and encrusting gypsum and anhydrite, cleaned of any diagenetic carbonate, and then digested in concentrated trace grade nitric acid. Samples will then be diluted, and analyzed via inductively coupled mass spectrometry. The REE composition of the bone apatite is acquired during the early diagenesis of the bone and can help indicate the chemistry of the depositional environment and can be used to determine time-averaging. The unique REE patterns can also be used to chemically finger-print bones for purposes of assessing poaching from public lands. Illegal excavation and sale of fossil bones from public lands is a major hinderance to the paleontologic community making this study an important way to combat theft of fossil bones.