Styles of tectonic inversion within syn-orogenic basins: examples from the Central Apennines, Italy

The geometry of several thrust-related folds in the Central Apennines of Italy results from a switch in deformation regime, from extension to contraction. This switch in tectonic regime occurred during the deposition of syn-orogenic sediments, and the emplacement and migration of the thrust belt–foredeep system towards the foreland in Neogene time. The styles of positive tectonic inversion result from normal faults that were steepened, rotated and truncated by thrusts, with local development of minor folds due to buttressing. Normal fault-controlled escarpments are also locally preserved in the forelimbs and backlimbs of thrust-related anticlines. The location and amplitudes of contractional structures across the belt reflects the distribution of pre-thrusting normal faults within precursor syn-orogenic basins, a result that may improve our understanding of the evolution of Apennine, as well as other thrust belt–foredeep systems.