Nicola Pelosi

Marine Geology and Morphobathymetry in the Bay of Naples (South-Eastern Tyrrhenian Sea, Italy)

Recent multibeam bathymetry (Elac, Bottomchart MK2) and high resolution seismics (Subbottom Chirp and 1–4 kJ Sparker source), acquired in the frame of an on-going programme of sea-floor mapping of Naples and Salerno Bays (south-eastern Tyrrhenian margin, Italy) and financed by the National Geological Survey of Italy, allows to put new insights into the recent evolution of the bay. The morphology and stratigraphy of the continental shelf and slope appear strongly controlled by the interplay of volcanism and canyoning that acted along the Magnaghi and Dohrn axes. Detailed bathymetry reveals the complexity of the drainage pattern which consists of a previously unknown, dense network of minor tributary channels. At places, the Dohrn and Magnaghi canyon walls are intensively affected by slope instability, as evidenced by numerous submarine slides and scars involving large volumes of sediments. Previously unreported mound-shaped morphological highs (“Bacarozzi” Facies), Holocene reworked sediments and sea-bottom creep appear on acoustic Chirp profiles in the inner sectors of the bay and seem to be related to volcano-sedimentary processes. On the contrary, sedimentation over the shelf at the southern edge of the bay (Sorrento-Capri) seems less influenced by volcanic activity and seabed features include Late Pleistocene regressive sand bodies and Holocene patch reefs, coastal dunes and depositional terraces.

Planktonic foraminifera as bio‐indicators for monitoring the climatic changes that have occurred over the past 2000 years in the southeastern Tyrrhenian Sea

A high-resolution integrated study has been performed in a super-expanded marine record (sedimentation rate spanning from 11 cm/100 years to 20 cm/100 years) from the continental shelf area of the southeastern Tyrrhenian Sea. Planktonic foraminiferal distribution illustrates 6 major environmental changes during the past 2000 years: (i) the Roman Period-Dark Age transition (from herbivorous-opportunistic to carnivorous species); (ii) the Dark Age-MCA transition (from carnivorous to herbivorous-opportunistic species); (iii) the Medieval Classic Anomaly-Little Ice Age transition (a further and definitive change from carnivorous to herbivorous-opportunistic species); (iv) the period during the Maunder event between approximately 1720 AD and 1740 AD (turnover from the carnivorous planktonic foraminifer Globigerinodes ruber to the herbivorous-opportunistic planktonic foraminifer Turborotalita quinqueloba); (v) the Industrial Period (dominance of herbivorous-opportunistic planktonic foraminifera); and (vi) the Modern Warm Period at approximately 1940 AD (the last turnover in favor of herbivorous-opportunistic planktonic foraminifers, associated with an increase in benthic foraminifera). Our studies lead us to link this latter feature to an anthropogenic impact associated with the damming of Sele River (Salerno Gulf) at 1934 AD, which induced a change in the sediment input with a strong decrease in coarse-grained fraction and a probable alteration in nutrient supply. The δ(18) OG. ruber record of the past 2000 years shows the alternation of warm/wet and cold/dry events related to the Roman Period, the Dark Age, the Medieval Classic Anomaly, the Little Ice Age, the Industrial Period and the Modern Warm Period. The 5 evident δ(18) OG. ruber oscillations (between approximately 1325 AD and 1940 AD) coincide with the 5 minima in the solar activity record (Wolf, Spörer, Maunder, Dalton and Damon events).

Application of X-Band Wave Radar for Coastal Dynamic Analysis: Case Test of Bagnara Calabra (South Tyrrhenian Sea, Italy)

Sea state knowledge has a key role in evaluation of coastal erosion, the assessment of vulnerability and potential in coastal zone utilization, and development of numerical models to predict its evolution. X-band radar measurements were conducted to observe the spatial and temporal variation of the sea-state parameters along a 3 km long sandy-gravelly pocket beaches forming a littoral cell on Bagnara Calabra. We produced a sequence of 1000 images of the sea state extending offshore up to 1 mile. The survey has allowed monitoring the coastline, the directional wave spectra, the sea surface current fields, and the significant wave heights and detecting strong rip currents which cause scours around the open inlets and affect the stability of the submerged reef-type breakwaters. The possibility to validate the data acquired with other datasets (e.g., LaMMA Consortium) demonstrates the potential of the X-band radar technology as a monitoring tool to advance the understanding of the linkages between sea conditions, nearshore sediment dynamics, and coastal change. This work proves the possibility to obtain relevant information (e.g., wave number, period, and direction) for evaluation of local erosion phenomena and of morphological changes in the nearshore and surf zone.

Recurrent Superficial Sediment Failure and Deep Gravitational Deformation in a Pleistocene Slope Marine Succession: The Poseidonia Slide (Salerno Bay, Tyrrhenian Sea)

A large number of exposed scars, originated by multievent sediment failures, have been identified on the southern flank of a deep submarine valley in Salerno Bay (Southern Tyrrhenian Sea), between depths of 300 and 700 m. A 200 km2 complex landslide lies across a 17 km-long SW-NE trending anticline, which is exposed 40 m above the seafloor of the continental slope and folds a Pleistocene marine successions. The exposed anticline, as well as others which are more subdued, have been formed by gravity-driven deformation of a deep and unconsolidated slope succession. The deep deformation seems to be coeval with recent stages of regional tectonic activity, given that a regional unconformity related to MIS 6 lowstand seals both the deep landslide features and the fault planes. A combined dataset of 2D high resolution seismics, swath-bathymetric digital elevation model of the seafloor and a gravity core was used to establish a possible relation between recurrent sediment failures at the seabed and the stack of positive reliefs in the compressional toe region of the buried landslide system and to learn more on the timing of the deformation phases.

Historical maps and satellite images as tools for shoreline variations and territorial changes assessment: the case study of Volturno Coastal Plain (Southern Italy)

Anthropic pressure has caused severe variations of Mediterranean coastal areas currently hosting about 480 million people. The replacement of natural land covers with crops and urban environment coupled with the reduction of sediment supply to the coast, subsidence, Relative Sea Level Rise and the high frequency of storm events, have caused severe shoreline erosion. In this paper, we stress the key role of historical maps, topographic maps and free satellite images to forecast the rates of coastline changes and to recognize the main features of past landscapes as tools for risk reduction. This data was recorded into a Geographical Information System dedicated to coastal management that allows to compare different coastal zones and elaborate maps. The analysis was applied to the case study of Volturno Coastal Plain (VCP), extending from the town of Mondragone to Patria Lake (Campania Region, Southern Italy). Indeed, the intense territorial modification that occurred between the seventies and eighties, coupled with the exposure to coastal erosion, make the VCP a good test area. The spatial analysis algorithms allowed to outline the main features of past landscapes and how they changed from roman times to present while the coastal evolution (erosion, accretion) and possible future coastal trend was assessed with the Digital Shoreline Analysis System (DSAS) software. Starting from the Bourbon domain, the reclamation caused the first great territorial change (e.g. wetlands were transformed into agricultural lands, regimentation of surperficial water) but the negative effects of antrophic pressure, as the intense urbanization of the coastal belt, emerged in the seventies of the last century. The shoreline position was defined for 9 time intervals (from 1817 to 2012) as the ratio of the distance between two shorelines and the relative elapsed time. Moreover, for the 1957–1998 and 1998–2012 time windows, the shoreline trends were calculated with the weighted linear regression method. The first trend pointed out an intensive erosional phase (mean value: 5 m/yr) for a wide sector close to the Volturno River mouth, the eroded sediment nourished the beaches of other coastal sectors. This phase was related to the reduction of River sediment supply mainly due to the construction of the Ponte Annibale dam on the Volturno River. The second (1998–2012) showed an alternation of erosion and accretion sectors due to a sediment starved condition to deltaic zone and to a sequence of 52 sea protection works in the Gaeta Gulf. Furthermore, the regression values of more recent time interval, was assumed as a scenario to draw the probable shoreline position in 2022. The overlay of this shoreline on the Technical Maps of Campania Region at 1:5000 scale highlighted the urban area that could be exposed to damages.