Stratigraphic and structural features of the Sibillini Mountains (Umbria-Marche Apennines, Italy)

In this paper we illustrate the stratigraphic and structural features of the Sibillini Mountains on the basis of a 1:40.000 geological map. Following the “Foglio 132 Norcia” (Geological Map of Italy at 1:100.000 scale; SCARSELLA, 1941), this new geological map is the first cartographic document that covers the whole area of the Sibillini Mts. This area is key for understanding the geological evolution of the external zones of the Apennine orogen, mostly owing to the pronounced structural elevation of the Apennine ridge at the Sibillini Mts. area. This allowed us to: a) carry out stratigraphic and structural analyses for the Umbria-Marche sedimentary cover to the oldest units; b) analyze the paleo-tectonic setting of this sector of the Afro-Adriatic continental margin and the behavior of pre-existing structures during the subsequent deformation events; c) investigate in depth the major Apennine thrust front (“Sibillini Mountains Thrust”) exposed in several sites (Fiastrone, Ambro, Tenna and Tronto valley) and its relationship with the units of the adjacent Messinian foredeep.