Ground Penetrating Radar to detect dinosaur bones within a Cretaceous hard limestone in Sicily

Ground Penetrating Radar (GPR) can be important in facilitating planning for the identification and extraction of buried vertebrate remains, particularly at sites that are difficult to access, where excavation would be costly and labor-intensive. This is the case at Grotta Lunga (northwestern Sicily), one of the southernmost European dinosaur sites, a key site for understanding the relationships between African and European dinosaurs. An incomplete theropod bone was discovered at this site in 2005, and to date there have been no further finds due to the difficulties of excavation in hard rock and in a cave environment. With the aim of exploring deeper into the rock volume around the bone, we tested GPR as a method to investigate the Cretaceous limestone at Grotta Lunga. Despite its potential, GPR has been rarely applied in paleontology and very seldom has led to the successful detection of buried dinosaur bones. Our analysis identified some remarkable GPR reflections on the cave wall, in the vicinity of the dinosaur bone, indicating the existence of reflective objects embedded in a position stratigraphically compatible with the dinosaur remains. Data processing was carried out to show the best result without compromising data quality. For this purpose we used the synthetic hyperbola method, Kirchhoff migration and Hilbert transform. The GPR signals detected at Grotta Lunga in the graphical form of hyperbolas are interpreted as the result of reflections produced by fossil bones embedded in the Cretaceous limestone investigated and indicate the presence of additional dinosaur remains. Our investigation provides useful information for planning future excavations.