GNGTS 2019 - Atti del 38° Convegno Nazionale

GNGTS 2019 S essione 1.2 135 THE BRADANO BASIN (SOUTHERN ITALY), TECTONIC AND STRATIGRAPHIC EVIDENCES OF A FRAGMENTED APENNINIC COLLISIONAL OROGEN IN THE IONIAN SEA J. Basso 1 , A. Artoni 1 , L. Torelli 1 , A. Polonia 2 , M. Carlini 3 , L. Gasperini 2 , P. Mussoni 1,4 1 Department of Chemistry, Life Sciences and Environmental Sustainability University of Parma, Parco Area delle Scienze, 157/A - Parma, Italy 2 Institute of Marine Science CNR ISMAR-Bo, Via Gobetti, 101, 40129 Bologna, Italy 3 Department of Biological, Geological and Environmental Sciences - University of Bologna, Via Zamboni 67, Bologna, Italy 4 ENI S.p.A., E & P Div., Via Emilia, 1 – 20097, San Donato Milanese (MI), Italy Abstract. The Bradano Basin is a key area to constrain the Africa-Eurasia collisional processes in the Central Mediterranean region (Faccenna et al. , 2014, 2001; Jolivet and Faccenna, 2000; Palano et al. , 2017). The Bradano Basin is located at the junction between the Southern Apennine and the Calabrian Arc, between the Ionian Calabrian Margin, to the West, and the Apulian Margin, to the East (Pescatore and Senatore, 1986; Pieri et al. , 1997; Rossi and Sartori, 1981). This basin is the site of pervasive tectonic deformation dissected by at least two major transverse structures and it is bounded to the east by the Apulian Foreland Ramp generally viewed as an “undeformed” foreland area (Catalano et al. , 2001; Doglioni et al. , 1999, 1996, 1994; Merlini et al. , 2000; Polonia et al. , 2011; Ricchetti et al. , 1988). Multi-scale, high-resolution seismic reflection profiles combined with exploration wells and seafloor bathymetry, reveals that active deformation involves the Apulia foreland ramp since Pliocene. Thrusts and thrust-related anticlines, together with an extensional fault system and two main transcurrent systems (the Amendolara Transpressive System and the Apulian Transtensive System) have been recognized to segment the Bradano basin. These tectonic structures were formed during two main tectono-stratigraphic events. During the first event (middle-upper Pliocene), the Southern Apennine thrust fronts, bounded to the west by the Amendolara left- lateral transpressive System, were activelymoving toward E onto theApulian plate above shallow detachment surfaces. Toward the end of this event, the Southern Apennines fronts thrust over the Pliocene Bradano Foredeep Basin while deeper detachment surfaces were activated and allowed the extensional fault system and the Apulian Transtensive System to be positively inverted. During the second event (from Pleistocene to Present), out-of-sequence thrusting reshaped the Southern Apennines orogenic wedge and the Amendolara Transpressive System became a NE-vergent (Apenninic) compressional feature; in the meanwhile, to the east, extensional and transtensional faults of the Apulian Transtensive System continued to be inverted. This reconstruction suggests that, since Pleistocene, the Bradano Basin whose outermost front is located in the Apulian Foreland Ramp can be considered part of the Southern Apennine orogenic wedge. Multichannel seismic and bathymetric data reveal that this region is undergoing compression and inversion of older extensional and transtensional fault systems implying it is part of a fragmented Apenninic collisional orogen and no undeformed foreland area can be recognized in this portion of the Ionian Sea. References Catalano, R., Doglioni, C., Merlini, S., 2001. On the Mesozoic Ionian Basin. Geophys. J. Int. 144, 49–64. doi:10.1046/ j.0956-540X.2000.01287.x Doglioni, C., Harabaglia, P., Martinelli, G., Mongelli, F., Zito, G., 1996. A geodynamic model of the Southern Apennines accretionary prism. Terra Nov. 8, 540–547. doi:10.1111/j.1365-3121.1996.tb00783.x Doglioni, C., Merlini, S., Cantarella, G., 1999. Foredeep geometries at the front of the Apennines in the Ionian Sea (central Mediterranean). Earth Planet. Sci. Lett. 168, 243–254. doi:10.1016/S0012-821X(99)00059-X Doglioni, C., Mongelli, F., Pieri., P., Pieri, Piero, 1994. The Puglia uplift (SE Italy): An anomaly in the foreland of the Apenninic subduction due to buckling of a thick continental lithosphere. Tectonics 13, 1309–1321. doi:10.1029/94TC01501 Faccenna, C., Becker, T.W., Auer, L., Billi, A., Boschi, L., Brun, J.P., Capitanio, F.A., Funiciello, F., Horvàth, F., Jolivet, L., Piromallo, C., Royden, L., Rossetti, F., Serpelloni, E., 2014. Mantle dynamics in the Mediterranean. Rev. Geophys. 52, 283–332. doi:10.1002/2013RG000444