Search

During the Late Pleistocene and Holocene periods, the Italian coasts have undergone a very articulated geological and geomorphological evolution, due to the complex and differentiated interaction of endogenous and exogenous dynamics. Aim of this study is to implement a geodatabase concerning the geomorphological, stratigraphic, biological and archaeological palaeo sea-level proxies located in the Gulf of Naples, in order to provide a catalogue of the most representative markers and an overall picture of ancient shorelines positions since the Late Pleistocene

In the last years, the activities of Working Groups (WGs), in the framework of Italian Association of Physical Geography and Geomorphology (AIGeo), were aimed at the new issue of the legend of the Italian Geomorphological Map. The activities were performed keeping in mind the necessity: 1) to add new symbols because the great progress made in geomorphology, in terms of new knowledge on geomorphological processes and landforms, after the first issue of the legend in 1994; 2) to have a legend usable with large scale maps, suitable for applied purposes; 3) to create a legend usable with softwares (GIS environment, etc). The WG on Coastal Morphodynamics contributed to this work, as well, promoting, through meetings and workshops, the debate among the Italian coastal geomorphologists on the approach needed to produce a modern geomorphological legend. The classic dichotomy forms-processes used in the geomorphological mapping is often based to static concepts, especially when applied to marine and coastal areas, affected by fast dynamic events, sometimes paroxysmal. We present the new geomorphological legend to represent both coastal and underwater contexts, aimed to the improvement of classic geomorphological legends. The main goal of the work was the production of a legend suitable to clarify the importance and the need of representing landforms in the context ofthe Quaternary evolution, as well as from more recent or modern processes.

This study was conducted within the framework of the “Coastal Morphodynamics” Working Group (WG) of the Italian Association of physical Geography and Geomorphology (AIGeo), according to the Institute for the Protection and Environmental Research (ISPRA) for the updating of the legend for the “Geomorphological Map of Italy”. The WG deals with the legend for the coastal areas, focusingits work on marine, lagoon and aeolian landforms, processes and deposits. In particular, the legend aims to classify coastal landforms in order to contribute to hazard and risk assessment,for supportingland-use planning and management. The legend allows the mapping of each landform in function of its genesis as well as its evolution and present dynamics, providing information about morphological characteristics at small and large scales. The relict morphological features and the active ones are reported along with the quantitative parameters useful for the description of the present wave/climate conditions and morphodynamics. As a result of the activities and experiments carried out by the “Coastal Morphodynamics” AIGeo WG during the last years, some examples of coastal geomorphological mappings at different scales (1:5,000 and 1:25,000) have been developed and are presented in this paper. The maps focus both on littoral plains and rocky coast dynamics as well as on the interactions with anthropic modifications.

The object of this study is the estimation of the long-term erosion rate in the southern portion of the Apennines chain (southern Italy). This was done with the aim of validating the hypothesis, proposed by MAZZOLI et al.. (2008), that thin-skinned extensional tectonics played a major role in the exhumation of formerly deeply buried tectonic units. More in detail, the study aimed at providing data on the erosional component of the rock exhumation which, based on Apatite Fission Tracks data reported in MAZZOLI et al. (2008), has affec- ted in the last 10 Ma the deepest units in the southern Apennines fold–and-thrust belt. The erosion rate was estimated based on the evaluation of the volume of deposits delivered by a large hydrographic basin to a conti- nental environment sedimentary basin. The accumulation basin is the Sant’Arcangelo basin (hereinafter BSA), which developed as a marine environment wedge-top basin (originally connected to the Apennines foreland basin) during the Middle Pliocene and evolved as an alluvial-lacustrine basin in the late part of the Early Pleistocene in response to the thrusting related uplift of a ridge located to the E of it (VEZZANI, 1966, 1967; CARBONE, 1991; PIERI, 1994; ZAVALA, 2000; PATACCA & SCANDONE, 2001; GIANNANDREA & LOIACONO, 2003; BENVENUTI et al., 2006). The drainage basin correlated to the BSA covers a large portion of the eastern slope of the Southern Apennines, and includes elevations formed of formerly deep-seated structural units (namely, Lagonegro units and Apulian platform unit) exhumed during Pliocene-Quaternary times. Literature data and field surveys allowed the identification of the sedimentary unit (Castronuovo-San Lorenzo unit, CSL, composed of lacustrine deposits passing laterally and upwards into alluvial plain sediments) which was deposited within the BSA when the basin was isolated from the neighboring foreland basin. The CSL ranges in age from around 1 to 0,7 Ma (PATACCA & SCANDONE, 2001; MAT- TEI et al., 2004; SABATO et al., 2005). G.I.S. elaborations allowed the reconstruction of the top and bottom surfaces and volume of the CSL. The calculated volume value was corrected accounting for the erosion which affected the CSL top surface, for the original width of the deposition area, for the suspended load loss, and for the sediment porosity. The paleo-hydrographic basin coeval to the CSL was reconstructed based on geomorphological/geological evidences, which include the compositional analysis of pebbles of different units of the BSA succession. The obtained 0,25 ± 0,07 mm/a erosion rate value is comparable to the values, averaged over the last 0,7 Ma and spanning from 0,2 to 0.3 mm/a, estimated for the eastern chain margin-foreland basin area in both the southern and northern Apennines (AMATO et al., 2003; CYR & GRANGER, 2008). These values, which can be considered as representative of erosion which has affected the Apennines over the Quaternary, are much lower than the Pliocene-Quaternary rock exhumation of formerly buried units estimated by AFT data, and this points to the important contribution of the extensional tectonics in the exhumation processes in the Southern Apennines.

International audience

La costa molisana è interessata da una prevalente tendenza all’arretramento che si è delineata marcatamente nel corso degli ultimi cinquanta anni. Le cause di tale tendenza non sono ancora ben chiare, e in particolare non sono disponibili ad oggi dati che consentano di valutare le possibili influenze climatiche. Il presente lavoro, pertanto, si è posto l’obiettivo di indagare sui rapporti tra dinamica costiera e parametri meteomarini e, in particolare, sulla possibile influenza di questi ultimi sulle recenti tendenze evolutive della linea di costa. A tal fine, è stato effettuato uno studio di dettaglio del settore costiero compreso tra la foce del torrente Sinarca e Campomarino Lido. Lo studio condotto ha consentito di caratterizzare tale settore dal punto di vista morfologico- dinamico e meteomarino, e di distinguerlo in tre tratti in base alla tendenza evolutiva recente ricostruita per ciascuno di essi. I dati acquisiti hanno permesso di evidenziare una stretta relazione tra regime ondoso e quello anemologico e una diversa sensibilità dei tratti distinti all’azione del moto ondoso e conseguente drift litoraneo, tale da suggerire una probabile relazione tra tendenze evolutive dei vari tratti e locali condizioni meteomarine. Lo studio ha permesso, inoltre, di accertare importanti variazioni del regime anemologico a partire dalla metà degli anni ’70. Queste variazioni, consistenti in un incremento significativo delle frequenze dei venti dominanti e regnanti provenienti dagli ottanti settentrionali e in una recentissima riduzione delle frequenze delle calme, hanno portato ad una maggiore esposizione del settore costiero esaminato all’azione delle ondazioni principali e quindi ad un incremento delle sue condizioni di rischio di erosione.

Several boreholes were studied in detail through different analytical methods in order to highlight the Holocene relative sea-level changes and the paleogeographical evolution of the southern sector of the Sele river coastal plain (Tyrrhenian Sea, southern Italy). Stratigraphic and paleontological analyses identified a transition from floodplain strata to brackish water, lagoon and upper shoreface deposits. The present setting of the outermost plain strip was interpreted as the result of a barrier-lagoon system which first migrated landward and then seaward during the Holocene. After being exposed to continental conditions during the Last Glacial regression, the study area gradually reached brackish water conditions at the beginning of the Holocene. Shortly before 6.7 ka cal BP the coastline reached its maximum retreat, reaching 1.6 km inland from the present shore. Subsequently, the barrier-lagoon system mainly prograded until marshy conditions were established, which partially persisted until very recent times. Four biological sea-level markers were sampled, and their ages, constrained by AMS 14C dating, span between 6.77 and 7.98 ka cal BP. Altitudes (m above mean sea level) of the collected samples were corrected taking into account the uncertainties of the vertical position with respect to the palaeo sea level. Vertical tectonic displacements were evaluated through the comparison between relative sea-level data and the Holocene predicted sea-level curve, as well as with the available morphotectonic and stratigraphic data. The results suggest negligible rates of vertical tectonic displacements during the Holocene, at least along the southern sector of the Sele river coastal plain.