GNGTS 2014 - Atti del 33° Convegno Nazionale

on the overlying Plio-Quaternary sediments suggest the presence of fluids mobilization that seep and rise to the seabed (Camerlenghi et al ., 2014). Some normal faults, probably generated by the detachment of the sequence on the salt layer, can favor the mobilization of the salt producing rollover of the UU. More severe rollover processes are evident on the west Sardinia slope (Fig. 2B3), where they produced block faulting and rotation of the UU and the Plio- Quaternary sequence, sometimes reaching the sea bed. The decollement and movement of salt and of the overlying sequence toward the deep basin represent important contributes to the halokinetic activity that develops at the foot of the escarpments, producing a large number of salt diapirs. The Plio-Quaternary sequence has a very changeable thickness, specially due to the halokinetics that produces little basins between the diapirs and important thinning on the top and around the same structures. Regionally talking, the Plio-Quaternary sequence is some hundreds of msec in thickness (TWT), sometimes reaching one second (TWT), that is more than 1000 m. In the Sardo-Provençal basin this thickness increases toward north-west, due to Fig. 2 – Comparison between the UU and MU MSC sequences of the Algero-Balearic basin (A1, A2, A3) and of the Sardo-Provençal basin (B1, B2, B3). Each comparison are at the same scale. In details A1 and B1 the analogy of the seismic facies of the UU is showed, characterized by a 9-10 package of reflectors; A2-B2 compare the thickness of intra UU halite layers between the basins, which generally doesn’t exceeds 15-20 ms of time thickness and, rarely, forms salt diapirs in the Algero basin as evidenced in the portion of seismic profile SF12-07. A3–B3 compare the UU deformation on the foot of the margins: at the base of the south Balearic margin the UU are mostly affected by possible fluids mobilization producing a specific evaporite seismic facies (as showed in zoom z1); rollover is not so pronounced as in the west Sardinia margin. Location of profiles in Fig.1. 160 GNGTS 2014 S essione 1.2