High Quality Content by WIKIPEDIA articles! The Adamantina Formation is a geological formation in Brazil whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation. According to most studies, the Adamantina Formation dates from the Turonian to the Santonian stage (90-83.5 million years ago) of the late Cretaceous, although some studies found much younger age - Campanian to Maastrichtian (83.5-65 million years ago) of the late Cretaceous.