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[1] Messinian foraminiferal stable oxygen and carbon isotopes of the Montemayor-1 core (Guadalquivir Basin, SW Spain) have been investigated. This record is exceptional to study the Mediterranean Outflow Water (MOW) impact on the Atlantic meridional overturning circulation (AMOC) and global climate during the Messinian because the core is near the Guadalhorce Corridor, the last Betic gateway to be closed during the early Messinian. Our results allow dating accurately its closure at 6.18 Ma. Constant benthic d18 O values, high difference between benthic and planktonic d 18 O, and low sedimentation rates before 6.18 Ma indicate the presence of a two-layer water column, with bottom winnowing due to an enhanced Mediterranean outflow current. The enhanced contribution of dense MOW to the North Atlantic Ocean likely fostered the formation of North Atlantic Deep Water (NADW). After 6.18 Ma, benthic d18 O values parallel that of the global glacioeustatic curve, the difference between benthic and planktonic d18 O is low, and sedimentation rates considerably increased. This indicates a good vertical mixing of the water column, interruption of the MOW, and a dominant glacioeustatic control on the isotopic signatures. According to the role of MOW in the modern Atlantic thermohaline circulation, the reduction of the MOW after the closure of the Guadalhorce Corridor might have resulted in a decreased NADW formation rate between 6.0 and 5.5 Ma weakening the AMOC and promoting northern hemisphere cooling. After the Gibraltar Strait opening, the restoration of the MOW and related salt export from the Mediterranean could have promoted an enhanced NADW formation.

Historical data show that the Gulf of Cadiz has been exposed to destructive tsunamis during at least the past 2000 yr. The last tsunami was generated by the AD 1755 Lisbon earthquake, which affected the Atlantic coasts of Spain, Portugal and Morocco. Today, these littoral areas are intensely populated and the expected damage could be much greater. Tsunami studies are of great importance in helping to determine the recurrence interval of these events.The presence of washover fan deposits on the inland margin of the Valdelagrana Spit bar (Cadiz, Spain) indicates the occurrence of a high energy marine event ca. 2300 cal. yr BP. Historical, geomorphological, sedimentological, palaeontological and geochronological data suggest that a tsunami could have affected the area during Roman times.

SlUlll ll ary.Sedimentological and palaeoecological observations, accompanied by archaeological determinations and absolute dating, have been carried out on a recent beach-barrier system succes sion located 20 km south of Siracusa, south-eastern Ionian coast of Sicily (Italy) . These deposits fi ll the back edge of a ria incised within Miocene limestones and are composed of three main stratal units characterized by distinct sedimentological fe atures. The two lower units, fo rmed by cross bedded sands and laminated days, recorded the development of a small confined beach-barrier depo sitional system, influenced by fr equent high-energy events. The upper unit, represented by chaotic coarser sediments, can be attributed to a destructive marine high-energy event. The physical prop erties of the composing stratal units and the morphological setting of the study area allowed us to reconstruct a suite of storm-and tsunami-related marine depositional processes that might have occurred in recent times along this area of elevated seismicity. In particular, absolute dating and archaeological determinations allow correlating the upper unit to a tsunami wave triggered by the 1693 AD catastrophic earthquake. The same depositional mechanism can also account for some of the coarse levels occurring into the underlying stratal units.