GNGTS 2014 - Atti del 33° Convegno Nazionale

while migrating these wedges have undergone significant shortening, of the order of tens of kilometres (Finetti, 2005b; Finetti et al. , 2005). The shortening evidenced by CROP sections contrasts with the horizontal extension that is predicted in the migrating arc by modelling (Fig. 1). �� ��� ���� ���� ������ �� ������� �� ��� In the Arc, this regime is induced by the trench suction force exerted by the sinking slab, while in the foreland extension develops in response to the downward pull of its subducted portion. At present, theAdriatic foreland is constituted by the inner continental domain of theAdriatic promontory. The western oceanic margin (Ionian Tethys by Finetti, 2005c) of this promontory (in front of the Southern Apennines belt ) was consumed under the eastward migrating Arc. Then, such subduction process came to an end around the late Miocene-early Pliocene (Cello and Mazzoli, 1999; Finetti et al. , 2005), in the southern Apennines consuming boundary, and around the upper Pliocene-lower Pleistocene, in the northern Calabria consuming boundary (e.g., Guarnieri and Carbone, 2003). The oceanic slab built up by such subduction is imaged in the CROP cross sections. The presence of major thrust fault systems clearly indicates that the continental Adriatic foreland has undergone strong shortening in the Pliocene, during the formation of the Tyrrhenian basin (Fig. 2). From the structural/tectonic features shown in the Fig. 2 – A) CROP cross section from the central Tyrrhenian (Vavilov basin) to the southern Apennines (modified after Finetti and Del Ben, 2005a). 1) Oceanic crust 2) Upper continental crust 3) Lower continental crust 4) Lithospheric mantle 5) Asthenospheric mantle 6) Remnants of the Alpine Tethys 7) Kabylo-Calabrides Units 8) Ionian Tethys oceanic slab 9) Ionides 10) Pre-Pliocene sedimentary cover 11) Pliocene-Quaternary sediments 12,13,14) Major thrust, normal and strike-slip faults of the Tyrrhenian stage, respectively. Black dots on the colours mark the Adriatic crustal units. B) CROP cross section from the southernmost Tyrrhenian (Marsili basin) to the Adriatic foreland, through the southern Apennines (modified after Finetti et al. , 2005). C) CROP cross section from the Marsili basin to Adriatic foreland, through Northern Calabria (modified after Finetti, 2005b). GNGTS 2014 S essione 1.2 153