Coexistence of fault‐propagation and fault‐bend folding in curve‐shaped foreland fold‐and‐thrust belts: examples from the Northern Apennines (Italy)

Terra Nova, 24, 396–406, 2012 Abstract Fault‐bend and fault‐propagation folds have unique profiles in foreland fold‐and‐thrust belts that are caused by different fault‐related folding models and controlled by the mechanical characteristic of the multilayer and/or by reactivation of normal faults in a positive inversion tectonics context. In this work, NNE–SSW‐ and NW–SE‐trending anticlines, related to the Neogene curve‐shaped Olevano‐Antrodoco‐Sibillini thrust (Northern Apennines, Italy), are investigated to reconstruct fault‐related folding mechanisms. Geological and structural analysis allows us to interpret the NNE–SSW‐trending anticlines as fault‐bend reactivation folds and the NW–SE‐trending anticlines as fault‐propagation shortcut anticlines. The coexistence of fault‐bend and fault‐propagation folding processes involving the same multi‐layered succession in different arms of a curve‐shaped thrust is explained in an inversion tectonics context. This along‐strike variation of different folding mechanisms might be recognised in similar curve‐shaped orogenic thrust‐belts controlled by structural inheritance.