Geological Map of the Frasassi Gorge (Northern Apennines, Italy)

This work presents a new 1:10,000-scale geological map of the Frasassi area (central Italy), integrating recent surface and cave surveys. The map is complemented by new data on the lithostratigraphic characterisation of the Calcare Massiccio Formation (MAS), which forms the core of the local Jurassic structural high. This refined analysis allows for a more detailed subdivision of the MAS and better correlation with the overlying condensed Jurassic succession (BU) and surrounding Maiolica Formation (MAI). The map documents the complex tectono-sedimentary contacts between these units, highlighting the geometry of the MAS–MAI boundary and the occurrence of neptunian dykes both at the surface and within the cave system. The proposed structural interpretation suggests that the Frasassi high was an elongated NW–SE block bounded by conjugate oblique-slip normal faults later reactivated during folding. The results refine the understanding of Jurassic paleogeography and post-Jurassic deformation in the northern Apennines and provide an updated framework to support future geological studies in the area.