THE PUGLIA UPLIFT (SE ITALY) - AN ANOMALY IN THE FORELAND OF THE APENNINIC SUBDUCTION DUE TO BUCKLING OF A THICK CONTINENTAL LITHOSPHERE

The Apenninic foreland shows two distinct structural signatures compar ing the central Adriatic Sea and the Puglia region. During the Pliocen e-Pleistocene the central Adriatic underwent high subsidence rates due to the eastward rollback of the hinge of the west dipping Apenninic s ubduction. The Puglia region and the Bradanic foredeep are located sou thward along strike in the same foreland, but, in contrast with the ce ntral Adriatic, after Pliocene-early Pleistocene subsidence they under went uplift since the middle Pleistocene. The geometry and the kinemat ics of the frontal accretionary wedge and related foreland changed fro m that moment on between the two areas. At the front of the central no rthern Apennines, off scraping and subsidence continued, whereas the f oredeep and foreland of the southern Apennines were buckled. Those dif ferences are interpreted as being due to the larger subduction hinge r ollback rate since middle Pleistocene of the central Adriatic lithosph ere (70 km thick) with respect to the thicker Puglia (110 km). The dif ferent thicknesses of the continental crust and lithosphere were inher ited from the Mesozoic rifting that disrupted the Adriatic plate. The different thicknesses appear to have controlled the variable degree of flexure of the lithosphere and its asthenospheric penetration rate. T he Tremiti E-W alignment is the right-lateral lithospheric transfer zo ne of those different tectonic regimes. The consequent different dip o f the subduction in the two sections (steeper west of Puglia) could al so explain the lower elevation of the southern Apennines, compared to their central-northern sector.