Ground-Penetrating Radar Prospections to Image the Inner Structure of Coastal Dunes at Sites Characterized by Erosion and Accretion (Northern Tuscany, Italy)

In this study we aimed to gain insights into dune formation and evolution from select coastal tracts of Northern Tuscany by inspecting their internal sedimentary architecture with Ground-Penetrating Radar (GPR) analysis. Erosion, equilibrium and accretion characterize the selected coastal tracts, and this analysis remarks on some GPR features consistently associated with specific coastal evolution states. A standard sequence of data processing made it possible to trace several radar surfaces and reflectors in the GPR profile, eventually interpreted in terms of depositional processes and erosive events. The stable or currently accreting coastal sectors show radar features compatible with a general beach progradation process, punctuated by berm formation in the general context of a positive sedimentary budget. Additionally, the radar facies distribution locally supports a mechanism of dune nucleation on an abandoned berm. Conversely, the GPR profile of the coastal sector today affected by erosion shows how a negative sedimentary budget inhibited coastal progradation and favored destructive events. These events interacted also with the active dunes, as demonstrated by the overlapping of wave run-up and aeolian radar facies. GPR prospections were effective at delineating the recent/ongoing coastal sedimentary budget by identifying radar features linked to construction/destruction phenomena in the backshore, and to dune nucleation/evolution.

Management of Posidonia Oceanica Leaf Litter in Calabrian Sandy Beaches (Southern Italy).

The wracks of Posidonia oceanica leaves on the sandy beaches of Calabrian region could be one of the most important defence against erosion processes. The management of Posidonia oceanica leaf litter in Italy has been realized through the mechanical removal and the transport in dumping areas of the beach-cast material. This solution, apparently simple and fast, produces a net loss of sediments from the sandy beaches and, therefore, a deficit in the sedimentary budget of coastline leading the coastal system to possible shore erosions. Instead, it could be better to keep these vegetable deposits on the place so to warrant a positive sedimentary budget and the tourist value of the regional beaches improving coastal tourism in the seaside resorts with bathing vocation.

MORPHOLOGICAL EVOLUTION OF THE BOTTOM OF THE POTOU LAGOON OVER THE LAST TEN YEARS (COASTAL ZONE OF COTE D'IVOIRE)

This study with a morphology and hydrosedimentology character was done to carry out a with an understanding the evolution of the channels and sedimentation in Potou lagoon in Ivory Coast starting from the realization of the bathymetric map. The bathymetry of this lagoon avered that the depths are lower than 2.11 m out of 22 km2, and presente three types of channels. In fact the channels in "U" represent a balance between the agents of accumulation and erosion. Channels resulting from processes of erosion which are in "V" and channels intermediate indicating an evolution of the type "V" in "U". In particular during these fourteen last years the Potou lagoon has sudden great phenomenon of deposit is a volume of +66791000.18 m³of sediments deposed on a surface which is thus estimated at 65.2 % of chenal surface. These deposits are certainly causes of full high funds in this lagoon. The mean velocity of sedimentation on Potou lagoon is thus estimated at 26.5 cm/year. As for the erosion, it could be estimated at-8487601 m³ a volume of on a surface wich is thus estimated at 34 % of chenal surface. The sedimentary budget would be thus estimated at+58303398.68449 m³ on a surface of 12.45 m2. A surface which is thus estimated at 0.8 %hasn’t sudden phenomenon of deposit or erosion. The bathymetric chart and the sedimentary budget of Potou lagoon are tools necessary for use of the stretch of water by the users. Thus, the zones at the risks determined on the bathymetric chart, such as the high bottom and the points of swirl generated by the depressions, will be easily avoided.

Sea-Level Rise and Shoreline Changes Along an Open Sandy Coast: Case Study of Gulf of Taranto, Italy

The dynamics of the sandy coast between Castellaneta and Taranto (Southern Italy) has been influenced by many natural and anthropogenic factors, resulting in significant changes in the coastal system over the last century. The interactions between vertical components of sea-level changes and horizontal components of the sedimentary budget, in combination with anthropogenic impact, have resulted in different erosion and accretion phases in the past years. Local isostatic, eustatic, and vertical tectonic movements, together with sedimentary budget changes, must be considered in order to predict the shoreline evolution and future marine submersion. In this study, all morpho-topographic data available for the Gulf of Taranto, in combination with Vertical Land Movements and sea-level rise trends, were considered by assessing the local evolution of the coastal trend as well as the future marine submersion. Based on the predicted spatial and temporal coastal changes, a new predictive model of submersion was developed to support coastal management in sea-level rise conditions over the next decades. After that, a multi-temporal mathematical model of coastal submersion was implemented in a Matlab environment. Finally, the effects of the relative sea-level rise on the coastal surface prone to submersion, according to the Intergovernmental Panel on Climate Change Assessment Reports (AR) 5 Representative Concentration Pathways (RCP) 2.6 and RCP 8.5 scenarios, were evaluated up to 2100.

Sedimentary Dispersal and Accumulation in the oceanic basin, South China Sea, revealed by Sediment Budget

<p>South China Sea (SCS) is not only the crucial pathway for transporting terrigenous materials from Eurasia to the Western Pacific Ocean since the early Oligocene, but also the dominant accumulation and preservation place as a result of limited material exchange between the semi-closed oceanic basin and the open ocean since the middle Miocene. Diverse factors, including global climate changes, eustatic sea level change, regional and local tectonic events, et al., controlled the sedimentary dispersal and accumulational patterns in the oceanic basin of the SCS, which can be revealed by the calculation of sediment budget at different geological times, as the sediment budget can illustrate directly the sediment influx, storage, loss in a basin system <em>(Hapke et.al, 2010).</em></p><p>By interpreting the multichannel seismic profiles covering the whole oceanic basin with constraints from International Ocean Discovery Program (IODP) Expeditions 349, 367 and 368, we reconstructed the sequence stratigraphy framework of the study area, and then calculated the sedimentary budget at different geological time. This work aims to quantitate the sedimentary dispersal and accumulation in the oceanic basin for the first time.</p><p>Until now we have completed the sequence boundary identification and dating, as well as the division of sedimentary units of all multichannel seismic profiles. The grid data of different sequence boundaries have been obtained and posted on the bathymetric map, and by the time-depth conversion with appropriate function in different region referred from the drilling results of IODP expeditions, we have figured out the thickness of each sedimentary unit. In the following we will do the decompaction correction before calculating the sedimentary budget of the whole oceanic basin at different times. This work could increase our understandings on the major controlling factors and possible material sources of the deposition process.</p><p> </p>

Testing the Prediction Ability of LEM-Derived Sedimentary Budget in an Upland Catchment of the Southern Apennines, Italy: A Source to Sink Approach

Landscape evolution models (LEMs) represent one of the most promising approaches to evaluate sedimentary budget, although factors such as the high number of parameters or the difficulty evaluating the robustness of the results can represent a limitation in their application in natural landscapes. In this paper, the Caesar–Lisflood LEM has been applied in a small catchment (i.e., about 9 km2) of southern Italy draining an artificial reservoir in order to test its ability to predict sediment flux and erosion rate. Short-term (i.e., about 20 years) estimation of the sediment volumes accumulated in the reservoir has been reconstructed by a bathymetric survey and compared to the results coming from the coeval LEM simulations. Results indicate a good accordance between LEM-based erosion volume estimations and direct sedimentation assessment, thus testifying to the high potential of such models to solve issues of sedimentary budget and short-term landscape modification.