GNGTS 2019 - Atti del 38° Convegno Nazionale

538 GNGTS 2019 S essione 3.1 margin could be interpreted. Below it, some stratified signals can be recognized that, on the old data with lower resolution, are just figured as one wave phase. So, to clarify this dilemma, we made some attribute sections in order to confirm the gas presence. All around our seismic lines a clear erosive surface between the Plio-Quaternary sediments and the Apulia carbonate platform top is detectable. We started to interpret this erosive surface on the OCSS_15 dataset, where it is evident and easy to recognize, while along the MS29 and ViDEPI seismic profiles it is difficult to detect. Furthermore, the high detail of the OCSS_15 lines allowed to identify another erosive surface that seems to coincide with the other one in the relative low structures (ancient Mesozoic graben) and split-in-two in the higher carbonate platform sectors (Mesozoic horst). Hence, thinking about their relative position, two major events could be considered: the Messinian Salinity Crisis and the Zanclean Flood (Fig. 2). We also made time-structural and time-isopach maps of each analyzed seismostratigraphic features. These maps show that the current seafloor morphology is slightly governed by the buried carbonate platform shape. The thickness map of the formation comprises between the Messinian and the Zanclean erosive surfaces shows a sediment accumulation above the carbonate platform highs. Also confirmed by a local flattening of the top of the Apulia carbonate platform that results as an isolated and elevated basin where sedimentation could occur, maybe showing evaporitic characteristics. Therefore, taking in mind all the information we opted for the hypotheses which considers i) the so called Bolognano Formation of Late Miocene age, below the MES (Marginal Erosive Surface – Messinian Age), ii) the Lower Pliocene between the MES and the ZAN (Zanclean erosive surface – Zanclean Age), and iii) the Late Pliocene – Quaternary above the ZAN. Finally, we correlated deep and shallow structures having a look at the CHIRP profiles (Fig. 3): they show lots of coral mounds in proximity of the gas seepages coming from the wide Fig. 3 - Correlation between deep and shallow structures – different details from multi-channel reflection seismic and CHIRP data.