Platform-to-basin facies transition and tectono-sedimentary processes in the Jurassic deposits of the Furlo area (Umbria-Marche Apennines, Italy)

Abstract

The Jurassic successions of the Furlo area (Northern Marche, Italy) are characterized by complex tectono-stratigraphic relationships related to the extreme differentiation of depositional environments occurring from the early Jurassic. In the area of the future Umbria-Marche Apennines, including the Furlo sector, the Sinemurian tectonic event dismembered the wide peritidal carbonate platform of the Calcare Massiccio Fm. into a series of uplifted and downthrown platform blocks bounded by extensional faults. The subsequent drowning of these blocks led to the development of two main environments: pelagic carbonate platforms and basins. The present paper focuses on an analysis of facies that characterize some paleogeographic sectors connecting these two different environments in order to understand the role of tectonics as a control on sedimentary processes. In these sectors, different types of facies have been identified and interpreted. Relationships between facies types, their stacking pattern, and sedimentary structures enabled the identification of different depositional processes directly or indirectly controlled by the tectonic evolution of the study area. The data compiled, compared with those from the literature, were used to relate the Furlo area to a general pelagic carbonate ramp environment constituted by two tilted and drowned carbonate platform blocks; these originated as a result of early Jurassic tectonic activity characterized by some approximately perpendicular faults showing a prevailing rotational character.