Pre-thrusting normal faults within syn-orogenic basins of the Outer Central Apennines, Italy: implications for Apennine tectonics

Extensional deformations are common within foredeep basins, and generally consist of hinterland-dipping normal faults located at the foredeep-foreland transition zones. Normal faults at the belt- foredeep boundaries, by contrast, are far less documented, nor their occurrence is predicted by simple orogenic load models. New sur- face data integrated with available seismic reflection profiles across the Central Apennines of Italy reveal the occurrence normal faults located in the inner edges of foredeep depressions. Extensional def- ormations are systematically found within sequentially younger Tor- tonian, Messinian and Early Pliocene foredeep basins, thus suggest- ing that normal fault development was an intrinsic feature of the evolving belt-foredeep-foreland system. Foreland extension is consis- tent with existing geodynamic models for the Apennines, and could represent the effects of lithospheric bending: its recognition and doc- umentation elsewhere could provide significant insights to improve our understanding of syn-orogenic basin dynamics