651 research outputs found

    SEA LEVEL CHANGE ALONG THE TYRRHENIAN COAST FROM EARLY HOLOCENE TO THE PRESENT

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    In any discussion of the evolution of a river basin, the history of sealevel change is important since river gradients and delta developments are strongly influenced by local sea level. Also, sea level provides a reference for inferring past vertical tectonic stability from the geological record. Hence it is appropriate that the discussion on the Tiber basin starts with sea level change along the Tyrrhenian coast during the Holocene. The past evidence for sea level comes from inferences of the position of the sea surface with respect to the present. Hence it is a relative measure; a function of both the changing position of the ocean surface and of the land surface or an integrated measure of changes in ocean volume, land movement and redistribution of water within the ocean basins. The observation therefore contains information on all the processes that change these surfaces: on geophysical, glaciological and oceanographic processes

    MEDFLOOD project: MEDiterranean sea-level change and projection for future FLOODing

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    MEDFLOOD is a four-year interdisciplinary project recently launched by a team of scientists working in fields concerned with Mediterranean sea-level change. The project has the timely and ambitious aim to build a spatially explicit database of relative sea levels for the Mediterranean and to use this resource to model risk and help project future flooding in and around the Mediterranean basin

    Marine notches in the Maltese Islands (central Mediterranean Sea)

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    We present the first detailed survey of tidal notches in the central Mediterranean area, in particular along the coastline of Gozo and Comino (Malta). The Maltese Islands represent one of the few sites in the Sicily Channel which exhibits coastal carbonate rocks. Marine notches on the islands of Gozo and Comino were surveyed by means of a seven day continuous snorkeling survey around the entire perimeter of the two islands. We surveyed the occurrence, lack and typology of marine notches and we correlated them with late Holocene sea level changes. Sea temperature (T) and electrical conductivity (EC) were collected along the route in order to locate the submarine springs and to relate them to the surveyed notches.A well-carved continuous roof notch was discovered along most of the plunging cliffs. It is well-carved out, in particular along the northern and western coast of Gozo. It develops from about 0.2 m above the mean sea level down and it can be up to 1.5–2 m deep. On the contrary, tidal notches are localised only in 8 sites. In 2 sites, Vermetid trottoirs develop at low tide level. In addition, at about −7 m to −10 m m.s.l., a 2–5 m wide marine terrace develops along extensive tracts of plunging cliffs, always in correspondence with the roof notches. This submerged terrace seem to be the result of the late Holocene slowdown of the sea level rise, which started to smooth the terrace and to carve out the submerged part of the roof notch, thanks to the exposed location of the islands and the favourable lithology.Through the collection of hydrological data, the presence of 21 submarine springs were detected. They occur mainly in the south-western coast of Gozo and on eastern coast of Comino. Anyway, marine notches seem not to be related to the freshwater outflow, such as those in the Adriatic Sea, because the studied islands are very exposed. As a consequence, along the Maltese islands bioerosion seems to be the most effective process in notch development.peer-reviewe

    Reply to comment by C. Morhange, C. Flaux, P. A. Pirazzoli, M. B. Carre on Holocene sea level change in Malta

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    The pits of Birzebbugia are located near the present-day mean sea level, and some are partially submerged. They were dated using pottery discovered in an archaeological site close to the coast, dated to the Bronze Age (Zammit, 1928; Abela, 1999). As they have been interpreted as sites for the retting of flax, during their utilization they should have remained dry and the sea could not submerge them. This is the reason why these structures are not directly related to the sea level, as suggested by Biolchi et al. (2011), so they represent an upper limit.peer-reviewe

    Holocene sea level change in Malta

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    A multidisciplinary approach has been applied to study sea level changes along the coast of Malta using data collected from underwater archaeological remains. The elevation of archaeological markers have been compared with predicted sea level curves providing new bodies of evidence that outline the vertical tectonic behaviour of this region, allowing estimation of the relative sea level changes that occurred in this area of the Mediterranean since the Bronze Age. During the Roman Age, sea level was at −1.36 ± 0.1 m, while in the Midde Age it was at −0.56 ± 0.2 m, in agreement with previous estimations for the Mediterranean region. Data indicate that Malta was tectonically stable during the studied period. The occurrence of the present-day notch along the coasts of the island indicates recent vertical stability of the area. The lack of MIS 5.5 deposits all over the island could simply be due to high rates of erosion, as its coasts are highly exposed to storm waves, rather than tectonic movements. However, even very slight vertical movements could completely remove field evidence. The relative stability of the Maltese Islands allowed a first attempt to provide a palaeoenvironmental reconstruction of its coasts at different time windows since the Last Glacial Maximum. The results have been used to infer time and mode of mammal dispersal to the island during the Pleistocene.peer-reviewe
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