GNGTS 2014 - Atti del 33° Convegno Nazionale

the important sediment supply by the French rivers while in the northern sector of the Algero- Balearic basin the Plio-Quaternary thickness is more regular, with a SE-ward thickening due to the deeper top of the Messinian UU. The thickness of the Plio-Quaternary sediments is a further important features contributing to the halokinetic process, in fact the larger diapirs are present in the central part of the Sardo- Provençal and Algero-Balearic basins: they can often reach the sea bed with 2-3000 and more meters in height. This phenomenon is particularly evident in the central Sardo-Provençal basin. To the north of the EBE some salt evidence has been recognized within rise basins (Fig. 3A); this Messinian sequence was deposited in some graben structures that seem to be remnants of the rifting phase. Here a well reflecting sequence of high amplitude reflectors can be ascribed to the UU, with a time thickness of about 100 ms TWT. Below this unit the transparent facies of salt can be distinguished, producing salt domes that are gradually more evident toward the basin (SE). To the north, the UU pinches out and onlaps the relief structures generated by normal faults. To the upper part of both the slopes of the studied basins we observe some high reflective horizons drastically cut by erosional surface interpret as Top Erosional Surface (TES, Fig. 3B). The reflecting layers are probably a remnant of UU. Also in the middle slope of the West- Sardinia margin Geletti et al. (2014), recognized the erosional truncations of the Marginal Erosional Surface (MES) as a well-defined reflector: locally it is on the top of an eroded high reflecting sequence associated to remnant of evaporite sequence (Fig. 3C). Fig. 3 – A) Part of the SF12-09 seismic profile. A high reflecting UU covers a thin layer of MU, here evidenced by salt diapirism; the dotted blue line depicts its base. The erosion TES of the high reflecting horizons on the upper part of the slope of the south Balearic margin (B) and on the middle slope of western Sardinia margin (C). PQ is Plio-Quaternary sediments; LP-Lower Pliocene depicted by the typical semi transparent facies, UPQ the higher amplitude reflectors of the Upper Plio-Quaternary sequence. Location of profiles in Fig. 1. GNGTS 2014 S essione 1.2 161