Late Miocene-Quaternary compressive events in the Tyrrhenian side of the Northern Apennines.

Since late Miocene, the internal zones of the Northern Apennines have been affected by an extensional tectonic regime, affecting a previous orogen, that gave rise to basins infilled by marine and continental deposits. This tectonic regime has been considered the only one acting in the area since late Miocene. Recent research has demonstrated, at least locally, the existence of shortening events affecting the sediments of late Tortonian-Quaternary age. Four main compressive events, affecting bedrocks and basin filling deposits of the whole region, have been detected; they alternate with the extensional events and are considered responsible for the main regional unconformities. The main four compressive events detected in the internal areas can be dated to late Messinian, early Pliocene, late Pliocene and middle Pleistocene.