Quaternary geodynamics of the Apennine belt

The drastic tectonic reorganization that the Apennine belt has undergone around the middle Pleistocene is interpreted as a consequence of the fact that since that time the Adriatic plate has accelerated carrying the outer sectors of the Apennines, formed by the Molise-Sannio units, the eastern part of the Latium-Abruzzi platform and the Romagna-Marche-Umbria and Ligurian units. The consequent oblique separation between such mobile units and the western almost fixed part of the belt has been accommodated by sinistral transtensional deformation in the axial part of the chain. During this process the belt-parallel push of the Adriatic has caused rapid uplift, bowing and outward extrusion of the outer mobile units. It is argued that this geodynamic interpretation provides a plausible and coherent explanation for the observed deformation pattern in the Apennines and that, on the other hand, such a result can hardly be achieved by the alternative geodynamic models so far proposed.