We conduct the seismic signal analysis on vintage and recently collected multichannel seismic reflection profiles from the Ionian Basin to characterize the deep basin Messinian evaporites. These evaporites were deposited in deep and marginal Mediterranean sedimentary basins as a consequence of the "salinity crisis" between 5.97 and 5.33 Ma, a basin-wide oceanographic and ecological crisis whose origin remains poorly understood. The seismic markers of the Messinian evaporites in the deep Mediterranean basins can be divided in two end-members, one of which is the typical "trilogy" of gypsum and clastics (Lower Unit -LU), halite (Mobile Unit -MU) and upper anhydrite and marl layers (Upper Unit -UU) traced in the Western Mediterranean Basins. The other end-member is a single MU unit subdivided in seven sub-units by clastic interlayers located in the Levant Basin. The causes of these different seismic expressions of the Messinian salinity crisis (MSC) appear to be related to a morphological separation between the two basins by the structural regional sill of the Sicily Channel. With the aid of velocity analyses and seismic imaging via prestack migration in time and depth domains, we define for the first time the seismic signature of the Messinian evaporites in the deep Ionian Basin, which differs from the known end-members. In addition, we identify different evaporitic depositional settings suggesting a laterally discontinuous deposition. With the information gathered we quantify the volume of evaporitic deposits in the deep Ionian Basin as 500,000 km 3 ± 10%. This figure allows us to speculate that the total volume of salts in the Mediterranean basin is larger than commonly assumed. Different depositional units in the Ionian Basin suggest that during the MSC it was separated from the Western Mediterranean by physical thresholds, from the Po Plain/Northern Adriatic Basin, and the Levant Basin, likely reflecting different hydrological and climatic conditions. Finally, the evidence of erosional surfaces and V-shaped valleys at the top of the MSC unit, together with sharp evaporites pinch out on evaporite-free pre-Messinian structural highs, suggest an extreme Messinian Stage 3 base level draw 2 | EAGE CAMERLENGHI Et AL. | 5 EAGE CAMERLENGHI Et AL. 6 | EAGE CAMERLENGHI Et AL. 10 | EAGE CAMERLENGHI Et AL. | 21 EAGE CAMERLENGHI Et AL.

We conduct the seismic signal analysis on vintage and recently collected multichannel seismic reflection profiles from the Ionian Basin to characterize the deep basin Messinian evaporites. These evaporites were deposited in deep and marginal Mediterranean sedimentary basins as a consequence of the “salinity crisis” between 5.97 and 5.33 Ma, a basin‐wide oceanographic and ecological crisis whose origin remains poorly understood. The seismic markers of the Messinian evaporites in the deep Mediterranean basins can be divided in two end‐members, one of which is the typical “trilogy” of gypsum and clastics (Lower Unit – LU), halite (Mobile Unit – MU) and upper anhydrite and marl layers (Upper Unit – UU) traced in the Western Mediterranean Basins. The other end‐member is a single MU unit subdivided in seven sub‐units by clastic interlayers located in the Levant Basin. The causes of these different seismic expressions of the Messinian salinity crisis (MSC) appear to be related to a morphological separation between the two basins by the structural regional sill of the Sicily Channel. With the aid of velocity analyses and seismic imaging via prestack migration in time and depth domains, we define for the first time the seismic signature of the Messinian evaporites in the deep Ionian Basin, which differs from the known end‐members. In addition, we identify different evaporitic depositional settings suggesting a laterally discontinuous deposition. With the information gathered we quantify the volume of evaporitic deposits in the deep Ionian Basin as 500,000 km3 ± 10%. This figure allows us to speculate that the total volume of salts in the Mediterranean basin is larger than commonly assumed. Different depositional units in the Ionian Basin suggest that during the MSC it was separated from the Western Mediterranean by physical thresholds, from the Po Plain/Northern Adriatic Basin, and the Levant Basin, likely reflecting different hydrological and climatic conditions. Finally, the evidence of erosional surfaces and V‐shaped valleys at the top of the MSC unit, together with sharp evaporites pinch out on evaporite‐free pre‐Messinian structural highs, suggest an extreme Messinian Stage 3 base level draw down in the Ionian Basin. Such evidence should be carefully evaluated in the light of Messinian and post‐Messinian vertical crustal movements in the area. The results of this study demonstrates the importance of extracting from seismic data the Messinian paleotopography, the paleomorphology and the detailed stratal architecture in the in order to advance in the understanding of the deep basins Messinian depositional environments.

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Well-preserved SSE-dipping low-angle normal faults (LANF) active during the Early Permian (Cisuralian) were recognized along the northern margin of the Orobic Basin (central Southern Alps, N Italy). These faults, which escaped most of the Alpine deformations, exhumed the Variscan basement during the deposition of the upper part of the Lower Permian succession (Pizzo del Diavolo Formation). Fault planes show evidence of frictional processes typical of the upper crust associated with hydrothermal circulation, responsible for the deposition of cm to m thick tourmalinite and Uranium mineralization.The recognized LANFs interacted with high-angle normal faults producing half grabens that stored the Lower Permian deposits, where synsedimentary fault activity in their hangingwall is testified by abrupt vertical and lateral facies changes, thickness variations and by soft-sediment deformations.Mesoscopic structures, exposed in the hangingwall of a major LANF (the Aga-Vedello Fault system) along a synthetic high-angle normal fault, include conjugate normal faults, horst-and-graben, domino-

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In the Northern Adriatic Sea, the occurrence of gas seepage and of unique rock outcrops has been widely documented. The genesis of these deposits has recently been ascribed to gas venting, leading to their classification as methane-derived carbonates. However, the origin of seeping gas was not clearly constrained. Geophysical data collected in 2009 reveal that the gas-enriched fluid vents are deeply rooted. In fact, the entire Plio-Quaternary succession is characterized by widespread seismic anomalies represented by wipe-out zones, and interpreted as gas chimneys. They commonly root at the base of the Pliocene sequence but also within the Palaeogene succession, where they appear to be associated to deep-seated faults. We suggest that there is a structural control on chimney distribution. Chimneys originate and terminate at different stratigraphic levels; commonly they reach the seafloor, where authigenic carbonate deposits form locally. Gas analyses of some gas bubble streams just above the rock outcrops reveal that gas is composed mainly of methane. Geochemical analyses performed at four selected outcrop sites show that these deposits formed as a consequence of active gas venting. In particular, geochemical analyses indicate carbonate precipitation from microbial oxidation of methane-rich fluids, although a straightforward correlation with the source depth of gas feeding the authigenic carbonates cannot yet be clearly defined.

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