Foreland-dipping normal faults in the inner edges of syn-orogenic basins: a case from the Central Apennines, Italy

Extensional deformations are common within foredeep basins and generally co nsist of hinterland-dipping normal faults located at the foredeep-foreland transition zones. Foreland-dipping normal faults at the belt-foredeep bound aries, by contrast, are far less documented and their occurrence is not pre dicted by simple orogenic load models. New surface data integrated with sei smic reflection profiles across the Central Apennines of Italy reveal the o ccurrence of foreland-dipping normal faults located in the inner edges of f oredeep depressions. Extensional deformations are systematically found with in sequentially younger Tortonian, Messinian and Early Pliocene foredeep ba sins, thus suggesting that normal fault development was an intrinsic featur e of the evolving belt-foredeep-foreland system and could have influenced t he stratal architectures of the host syn orogenic deposits. Foreland extens ion is consistent with existing geodynamic models for the Apennines and cou ld represent the effects of lithospheric bending: its recognition and docum entation elsewhere could provide significant insights to improve our unders tanding of syn-orogenic basin dynamics. (C) 2001 Elsevier Science B.V. All rights reserved.