Thrust-related Folds within Inversion Tectonics Dominated Areas - Structures from the Apennines Thrust Belt (Italy)

Thrust fault-related folds form important structural hydrocarbon traps in fold-and-thrust belts. This contribution presents the analysis and understanding of thrust-related folding within a thrust belt that suffered an extensional fault heritage by examining surface and subsurface examples from the Apennines thrust belt of Italy. The geometrical characterisation of the fold structures has been carried out by integrating field geological and structural data with the interpretation of seismic reflection profiles. The development of thrust-related folding models is discussed with respect to mechanical multilayers and the reactivation or thrust shortcut of a pre-existing normal fault. Fault-bend and positive flower structures or fault-propagation folds are developed respectively along oblique and frontal thrust ramps that characterise a curved thrust belt depending on the dominant positive inversion tectonic process and the mechanical stratigraphy of the involved multilayer.