Daniela Ruberti

Depositional system and response to sea level oscillations of the senonian rudist-bearing carbonate shelves. Examples from central Mediterranean areas

SummaryIn the Late Cretaceous the carbonate platforms modified the organization of their depositional systems owing to vast and complex geologic events. In this view, detailed analyses have been made on Senonian shelf-to-slope rudist-bearing limestones resting on pre-Coniacian erosive surfaces or slope facies in the Nurra region (northwestern Sardinia, Italy), in the central-southern Apennines and in the Gargano area (central-southern Italy). The main characteristic of the analyzed deposits is the spreading of rudists in a context of foramol-type calcite-dominated benthonic sediment-producer communities.The reconstructed Senonian depositional environments match a large complex of unprotected shelves that produced loose, diagenetically stable mollusc-dominated bioclastic debris which were not involved in significantin situ cementation processes. High energy episodes led to repeated and more or less total remobilization of the sedimentary sheet. On the shelves, both storm- and wind-induced currents and waves exercised a strong driving control on the sedimentary arrangement of the shifting biogenic sediments. The latter constituted large coalescing sheets of winnowed, loose, fine-to-coarse skeletal sands. Sandy sediments were easily involved in remobilization processes across the shelves toward the redepositional sites. Transport modality largely depended on the granular composition of the sediments. The early and almost continuous sweeping of the finer fraction (bioeroded-derived silt) resulted in an effective pre-sorting of the skeletal debris stored in the Senonian open shelf settings.In situ preservation potentiality of the produced skeletal material was low and huge amounts of sands may have concurred in forming slope aprons.In the studied successions a two-stage evolution is documented during the Senonian.- All over the latest Turonian-early Campanian interval the rudist-bearing shallow neritic platforms retreated, with seabed opening and deepening, and an underfeeding of the slope occurred. Probably, only where rudists strongly dominated the shelf assemblages (as in the case of the southern Tethyan carbonate platforms), their relatively high rate of bioclastic sediment production and supply might partially compensate for the increased accommodation space reducing the effects of the early Senonian transgressive phase.- In the late Senonian a huge amount of foramol skeletal sands prograded over the upper slope by means of impressive gravitative flows suggesting that main depocenters moved down-slope. The persistence of healthy, producing foramol open-shelves may be inferred by the occurrence of compositionally coherent displaced skeletal sands even if reduced findings of late Campanian-Maastrichtian shallow water limestones are known characterized by a clear upward shallowing trend. A reduced accommodation space in shallow water settings may have enhanced the high off-bank sand dispersion via an increased winnowing action exerted on loose foramol-bioclastic sediments in periods in which the shelf tops were exposed to intense current winnowing. The generalized down-slope migration of the main depocenters occurred during the late Senonian regressive phase. Owing to the peculiar characteristics of the foramol-type open shelves (e.g., physiography, sediment production and composition), the sediment distribution patterns of the Senonian rudist-bearing carbonate factories and their response to sea level fluctuations were strongly modified with respect to the commonly accepted carbonate platform chlorozoan standard model. Major progradational episodes of marginal sands occurred during both relative lowstands and terminal highstands of sea level. During transgressive phases only where the sediment production was sustained (southern Tethyan carbonate platforms), the rudist-bearing depositional systems might have dampened the typical drowning tendency of the foramol open shelves.

Cenomanian rudist-dominated shelf-margin limestones from the panormide carbonate platform (Sicily, Italy): Facies analysis and sequence stratigraphy

SummarySedimentological, paleontological and sequence analyses of Cenomanian limestones in Sicily reveal the facies architecture and dynamics of a Mid Cretaceous rudistdominated platform margin from Western Tethys. The studied deposits outcrop near Palermo, as part of a large structural unit of the Sicilian Maghrebids. They belong to the Panormide carbonate platform, a Mesocenozoic paleogeographic domain of the African margin.The lateral continuity of the beds along three nearly parallel E-W outcrop sections allowed the recording of cm/dm thick lithological and faunal variations. Nine main lithofacies associations have been recognised along about 200 m of subvertical strata. Their vertical and lateral organisation points to a transition from highenergy shelf-margin rudist patches and shoals to more internal lagoonal-tidal environments over a short distance.The lithofacies evolution and stacking pattern along the three sections made it possible to define elementary cycles, composite cycles and larger-scale sequences with a dominant shallowing-upward trend. Their hierarchical organisation implies that sea-level fluctuations were an important factor in their formation.The cycles are characterised by a great variation in facies as a result of transgressive-regressive events in different sectors of the inferred Cenomanian shelf. Subtidal cycles typical of the shelf margin (4–10 m-thick) are particularly well identifiable. They are made of large Caprinidae and Sauvagesiac rudstone-to-floatstone (about 2/3 of the total thickness), capped by rudist-conglomerates, often organised into 3–5 fining-upward amalgamated beds and showing, in places, effects of surface-related diagenesis. In more internal shelf areas the cycles consist of Caprinidae-Radiolitidae floastone grading up into amalgamated beds of angular bioclastic rudstone/grainstone. Alternations of foraminifer/ostracod mudstone/wackestone and bioclastic grainstone/fine-rudstone, capped by loferites and/or by other emersion-related overprintings, characterise the cycles formed in the peritidal zones.these cycles are stacked into three incomplete depositional sequences. The sequence boundaries have been identified by the abrupt interposition of peritidal cycles in subtidal rudist-rich cycles, with evidence of brief subaerial exposure.

Senonian rudist limestones in the Sorrento Peninsula sequences (Southern Italy)

Abstract Senonian carbonate sediments rich in rudists are widespread throughout central-southern Italy. TheConiacian-Santonian series, analyzed in the Lattari Mountains (Sorrento Peninsula), are almost completely composed of limestones, with very subordinate dolomitic beds. On a field scale we can distinguish rudist-rich beds rhythmically alternating with finer-grained foraminiferal beds. The studied series testify to a deposition in shallow-sea environments. In the lower part of the series periodical, more or less prolonged emersions (subaqueous with fresh/brackish waters or subaerial exposure) are documented. The upper part of the series lacks emersion evidence; submarine exposure surfaces are testified by firmgrounds or hardgrounds. Wave- and cross-laminations, HCS and the lack of fine sediments document an overall deposition under influence of occasional high-energy water regimes with some storm-related events. The sedimentology and taphonomic signature of the rudist shell beds have been described in order to get a better understanding of depositional environment and the physical processes that controlled the Senonian sedimentation. Monospecific tabular beds mainly characterize the lower part of the series; more complex rudist concentrations, characterized by moderate species diversity, increase up-section. The recognized lithofacies are organized in shallowing-upward depositional cycles that show a gradual change from peritidal/shallow-subtidal cycles to dominantly subtidal cycles up-section; this change records a general deepening-upward trend as a possible result of an increase of the accommodation space provided by a relative sea-level rise, according to what is suggested for other coeval Apennine and Sardinia series.

An integrated approach to environmental quality assessment in a coastal setting in Campania (Southern Italy)

The coastal region of Southern Italy’s Caserta province, known as the LitoraleDomitio (Domitia coast) has been subjected to increasing pressure from unsustainably fast economic and urban growth in the last century, that resulted in a induced serious land degradation. To obtain a comprehensive picture of the ecological status of the Domitia coastal zone (Campania, Southern Italy), a holistic methodology has been applied. Sedimentological, geochemical, and biological analyses of the surface sediments and water samples were performed along the submerged beach. The data were integrated using a geographical information system, together with information on past and present land use and human activities along the coast and in inland regions. Heavy metal concentrations in sediments plus As and Se (Cd, Co, Cr, Cu, Hg, Ni, Pb, V, Zn) and their enrichment factors, which are important for identifying polluted areas in countries like Italy (where environmental legislation has not yet established intervention limits), indicate excesses Cd, Cr, Pb, and V of probable anthropogenic origin. A microbiological contamination of marine waters has been detected by the Regional Environmental Protection Agency of Campania. The Bacteriological Quality Index map shows that bathing areas must be classified as “contaminated” and “highly contaminated”. High levels of chemical and biological contamination are particularly common in both bathing seawater and sediments along the coastal zone south of the Volturno River, where the existing wastewater treatment plant is not properly working, to date. Factory farming, which is widespread in the area, is likely to be an additional important source of contamination. In accordance with these conclusions, analyses of the benthic diatom community revealed dominance of eutrophic species.

Microstratigraphy and taphonomy of rudist shell concentrations in Upper Cretaceous limestones, Cilento area (central-southern Italy)

Abstract Rudist bed type and distribution has been investigated in Upper Cretaceous limestones cropping out in the northern Cilento area (southern Italy). These limestones are dominated by fine-grained, peloidal, silty packstone in which rudist-rich beds are intercalated. An inner shelf environment may be inferred on the basis of the recognized sedimentary and taphonomic features. The rudist shell beds are characterized by low species diversity, with slight differences in abundance of a few species belonging to the Durania, Bournonia, Sauvagesia, Gorjanovicia and Biradiolites genera, which usually form oligo- or monospecific congregations. The internal fabric of these levels (i.e. orientation, arrangement, packing and sorting of the skeletal elements; internal microstratigraphy) has permitted us to distinguish two broad shell bed categories: (a) shell beds considered as “Primary Shell Concentration”, in which the shell concentration is essentially created by the behaviour of local shell producers, preserved in situ and in growth position; (b) shell beds considered as “Hydraulic Shell Concentration”, which were deposited under the influence of hydraulic processes and/or input of surrounding bioclastic sediments. The taphonomic analyses allowed us to highlight the role of some of the biotic and abiotic factors that controlled the distribution of the rudists in the various habitats. The increase of physical disturbance (especially hydrodynamism) is the primary difference between these shell bed categories. The establishment and development of the densest rudist congregations appear to be related to the accommodation space made available by means of relative sea level rise. The lowering of the sea level was often accompanied by the increased influence of waves and/or currents on the seabed and the consequent sediment disturbance and demise of the rudist lithosome, although other factors cannot be excluded.

Rudist lithosomes related to current pathways in Upper Cretaceous, temperate-type, inner shelves: a case study from the Cilento area, southern Italy

Abstract Shallow-water foramol limestones have been studied from a locality in the southern Apennines in which outcrop conditions show an excellent overview of the lateral and vertical evolution of rudist bodies and allow their geometry and the dynamic aspects to be reconstructed. The lithofacies suggest open depositional settings characterized by peloidal silty-muddy sediments. Rudists inhabited well-defined sectors of these shelves, giving rise to wide biostromal bodies, and supplied most of the skeletal debris via bioerosion and minor physical breakdown. In particular, the characteristics of rudist lithosomes document the existence of a complex network of channel-like depressions. In such a depositional context, the evolution of rudist lithosomes was controlled by the environmental hydrodynamic conditions. The resulting composite rudist assemblages are characterized by often-toppled individuals, suggesting continuous sediment removal between the organisms. The good preservation of the shells and the common articulation of the valves, however, point to an absence of sustained transport but rather a slight sediment destabilization. The gross lenticular geometry of the shell beds could be related to the above-mentioned patterns of weak, perhaps channelized, pathways. In such a depositional context, rudist colonization on channel margins assumes particular importance as it documents the rudist ability to exploit a wide array of environments, comparable to that of oysters in Recent seas, and reflecting the probable opportunistic nature of rudists.

Human influence over 150 years of coastal evolution in the Volturno delta system (southern Italy)

This paper focused on the past shoreline change rates along the coastal plain of the Volturno River, in southern Italy, western Mediterranean. A wide database comprising historical maps, aerial photographs, topographic sheets, bathymetric data was used to extract the spatial and temporal information of the coastlines at seven time points. Coastline displacement was calculated for two successive time points and relative surface variation (accretion and erosion) was estimated as well as minimum and maximum accretion/erosion linear values and rates. The surface variation analysis has revealed that the studied coast can be considered homogeneous since the 1970s, whereas it exhibits a variety of shoreline evolutionary trends after that time period. Timing and causes of trends and rates of variation were detected. Based on the estimated shoreline change rates, an appropriate morhodynamic one-line model was applied to predict evolutionary scenarios also in presence of port and defence works. The results obtained strongly emphasize that a successful coastal management requires a constant monitoring of the human-induced changes to account for the variability of rates over time.

A sediment trap to mitigate port silting due to longshore transport. The case of Pinetamare Marina (Southern Italy)

The Pinetamare Marina, located SE of the mouth of the Volturno River and the Regi Lagni Canal (southern Italy), is interested by silting phenomena due to longshore transport of fluvial sediments. To eliminate this severe problem, the design of the new Marina includes the construction of a sediment trap, placed perpendicular to the breakwater, to prevent the accumulation of the sand sediments at the marina entrance. To study the efficiency of this solution, experiments were performed through a physical model in a wave basin, with appropriate scaling of the geometric characteristics and of the hydrodynamic processes. The experimental tests highlighted that the trap is able to intercept sediments and to mitigate the port silting for about two years, after which it is necessary to dredge the accumulated sand sediments. These sediments are used to compensate the erosion of the beaches downstream the breakwater.

Stratigraphic architecture and anthropic impacts on subsoil to assess the intrinsic potential vulnerability of groundwater: the northeastern Campania Plain case study, southern Italy

This study attempts to assess the aquifer vulnerability in the northeastern sector of the Campania Plain (southern Italy). The area is a highly populated region with anthropic impacts caused by rapid urban growth, quarrying, agricultural and industrial activities and uncontrolled waste storage. The main geologic feature of this plain is the alternation of alluvial/transitional and volcaniclastic deposits of Late Pleistocene–Holocene age. The study was performed integrating different sets of geologic and environmental data to restore the stratigraphic architecture and to assess anthropic impacts on subsoil. The reconstruction of stratigraphic subsurface architecture was based on remarkable geodatabase, concerning well log stratigraphies. Specific insights have been delineated on the volcaniclastic lithofacies heteropies across the entire area of study to highlight the differences in lithification degree and permeability. The contribution of pedogenesis on the reconstruction of the stratigraphic setting was also considered for the relative implications on groundwater quality concerns, as paleosols are usually regarded as aquitards. All of this information has been managed into a GIS project to produce a detailed 3D geological reconstruction, integrated with hydrogeological information to provide a model of the aquifer under study, highlighting sites of greater vulnerability to pollution. The anthropic impacts on subsoil were assessed by evaluating land-uses and overlaying the ANHI (Agricultural Nitrate Hazard Index) Map. The integration of the above datasets has allowed to check the reliability of the previsional empirical model with respect to the hydrostratigraphic model based on a thorough stratigraphic model and to verify the real potential of contamination.

Valutazione dei tassi di erosione nel bacino idrografico del Fiume Calore

PIETRO; Passadore, Giulia; Garbin, Silvia; B., Matticchio; F., Visentin; I., Brunet; R., Lago; F., Facco; Botter, Gianluca; Carniello, Luca. ELETTRONICO. (2016), pp. 1119-1122. ((Intervento presentato al convegno Convegno Nazionale di Idraulica e Costruzioni Idrauliche tenutosi a Bologna nel Settembre 2016. Original Citation: Un sistema modellistico integrato per la previsione in tempo reale delle piene del Muson dei Sassi (Pd)La XXXV edizione del Convegno Nazionale di Idraulica e Costruzioni Idrauliche (IDRA16), co-organizzata dal Gruppo Italiano di Idraulica (GII) e dal Dipartimento di Ingegneria Civile, Chimica, Ambientale, e dei Materiali (DICAM) dell’Alma Mater Studiorum - Universita di Bologna, si e svolta a Bologna dal 14 al 16 settembre 2016. Il Convegno Nazionale e tornato pertanto ad affacciarsi all’ombra del “Nettuno”, dopo l’edizione del 1982 (XVIII edizione). Il titolo della XXXV edizione, “Ambiente, Risorse, Energia: le sfide dell’Ingegneria delle acque in un mondo che cambia”, sottolinea l’importanza e la complessita delle tematiche che rivestono la sfera dello studio e del governo delle risorse idriche. Le sempre piu profonde interconnessioni tra risorse idriche, sviluppo economico e benessere sociale, infatti, spronano sia l’Accademia che l’intera comunita tecnico-scientifica nazionale ed internazionale all’identificazione ed alla messa in atto di strategie di gestione innovative ed ottimali: sfide percepite quanto mai necessarie in un contesto ambientale in continua evoluzione, come quello in cui viviamo. La XXXV edizione del Convegno di Idraulica e Costruzioni Idrauliche, pertanto, si e posta come punto d’incontro della comunita tecnico-scientifica italiana per la discussione a tutto tondo di tali problematiche, offrendo un programma scientifico particolarmente ricco e articolato, che ha coperto tutti gli ambiti riconducibili all’Ingegneria delle Acque. L’apertura dei lavori del Convegno si e svolta nella storica cornice della Chiesa di Santa Cristina, uno dei luoghi piu caratteristici e belli della citta ed oggi luogo privilegiato per l’ascolto della musica classica, mentre le attivita di presentazione e discussione scientifica si sono svolte principalmente presso la sede della Scuola di Ingegneria e Architettura dell’Universita di Bologna sita in Via Terracini. Il presente volume digitale ad accesso libero (licenza Creative Commons 4.0) raccoglie le memorie brevi pervenute al Comitato Scientifico di IDRA16 ed accettate per la presentazione al convegno a valle di un processo di revisione tra pari. Il volume articola dette memorie in sette macro-tematiche, che costituiscono i capitoli del volume stesso: I. meccanica dei fluidi; II. ambiente marittimo e costiero; III. criteri, metodi e modelli per l’analisi dei processi idrologici e la gestione delle acque; IV. gestione e tutela dei corpi idrici e degli ecosistemi; V. valutazione e mitigazione del rischio idrologico e idraulico; VI. dinamiche acqua-societa: sviluppo sostenibile e gestione del territorio; VII. monitoraggio, open-data e software libero. Ciascuna macro-tematica raggruppa piu sessioni specialistiche autonome sviluppatesi in parallelo durante le giornate del Convegno, i cui titoli vengono richiamati all’interno del presente volume. La vastita e la diversita delle tematiche affrontate, che ben rappresentano la complessita delle numerose sfide dell’Ingegneria delle Acque, appaiono evidenti dalla consultazione dell’insieme di memorie brevi presentate. La convinta partecipazione della Comunita Scientifica Italiana e dimostrata dalle oltre 350 memorie brevi, distribuite in maniera pressoche uniforme tra le sette macro-tematiche di riferimento. Dette memorie sono sommari estesi di lunghezza variabile redatti in lingua italiana, o inglese. In particolare, la possibilita di stesura in inglese e stata concessa con l’auspicio di portare la visibilita del lavoro presentato ad un livello sovranazionale, grazie alla pubblicazione open access del volume degli Atti del Convegno. Il volume si divide in tre parti: la parte iniziale e dedicata alla presentazione del volume ed all’indice generale dei contributi divisi per macro-tematiche; la parte centrale raccoglie le memorie brevi; la terza parte riporta l’indice analitico degli Autori, che chiude il volume.