Facies Architecture and Evolution of a Cretaceous, Tectonically-Controlled, Carbonate Slope from Western Sicily (Italy)

The stratigraphic architecture of a Cretaceous carbonate slope from north western Sicily (Italy) has been reconstructed on the basis of detailed field sections. The wire cut walls of a number of quarries that extract the Cretaceous limestones as ornamental stones allowed the mapping of the stratal architecture and lithologies at various scales. The vertical and lateral facies relationships in this about 1000 m thick depositional system account for a complex sedimentary dynamics along a carbonate platform escarpment that was strongly influenced by syn-sedimentary transtensional tectonics associated to magmatism. Although the original relationships with the carbonate platform were obscured by…

Collapsed paleocave system in Upper Triassic peritidal cycles from the Panormide Carbonate Platform, Sicily (Italy)

Soft-sediment deformation structures (SSDS) in Pleistocene calcarenites of Favignana island (Sicily, Italy)

Seismic stratigraphy of the north-westernmost area of the Malta Plateau (Sicily Channel): The Middle Pleistocene-Holocene sedimentation in a tidally influenced shelf

In this study we present the results of a seismic-stratigraphic analysis of sub-bottom profiles in the north-westernmost area of the Malta Plateau in order to define the depositional mechanisms for the upper Quaternary sequences. During this interval the morphology of the Malta Plateau was characterized by a ramp and bathymetries not exceeding 200 m. Two major unconformities, related to MIS 6 and MIS 2 (the latter corresponding to the Last Glacial Maximum, LGM), characterize the upper Quaternary sequences. The geometries of the recognized seismic units indicate as depositional mechanisms were controlled by subsidence and sea-level fluctuations. In detail, deposits related to the last glacia…

The integration of surface and subsurface stratigraphic data with HVSR measures for studies of seismic microzonation: the case of Oliveri (ME)

Because of its high seismic hazard the urban area of Oliveri has been subject of a study on seismic microzonation at first level (OPCM 3907/2010). The urban area develops on a large coastal plain made of Late Pleistocene and Holocene mixed fluvial/marine sediments, that mainly consist of silty sands and gravels. The eastern part of this plain is dominated by the alluvial deposits of the Elicona torrent. The coastal and alluvial sediments overlap a complexly deformed substrate made of Hercynian metamorphites (Aspromonte unit), the Capo d’Orlando Flysch, the Antisicilide Argille Scagliose and Pleistocene clays and calcarenites. This area is affected by high uplift rates as recently estimated …

Physico-chemical and mechanical characterization of in-situ forming xyloglucan gels incorporating a growth factor to promote cartilage reconstruction

Abstract The development of growth factors is very promising in the field of tissue regeneration but specifically designed formulations have to be developed in order to enable such new biological entities (NBEs). In particular, the range of therapeutic concentrations is usually very low compared to other active proteins and the confinement in the target site can be of crucial importance. In-situ forming scaffolds are very promising solutions for minimally invasive intervention in cartilage reconstruction and targeting of NBEs. In this work injectable, in-situ forming gels of a temperature responsive partially degalactosylated xyloglucan (Deg-XG) incorporating the growth factor FGF-18 are fo…

A MESOZOIC PALEOMARGIN in WESTERN SICILY, its TERTIARY EVOLUTION and its PRESENT-DAY SEISMOGENETIC POTENTIAL

Carbonate slope re‐sedimentation in a tectonically‐active setting (Western Sicily Cretaceous Escarpment, Italy)

Tectonic processes are widely considered as a mechanism causing carbonate platform margin instabilities leading to the emplacement of mass transport deposits and calciturbidites. However, only few examples establishing a clear link between tectonics and re-sedimentation processes are known from the lit- erature. The two-dimensional and three-dimensional wire-cut walls of hun- dreds of quarries extracting ornamental limestones (for example, Perlato di Sicilia) from the Western Sicily Cretaceous Escarpment in Italy expose a series of mass transport deposits. The depositional architecture, spatial facies distri- bution and sedimentary features of these deposits were studied in detail. Thin sec…

A regional-scale discontinuity in western Sicily revealed by a multidisciplinary approach: A new piece for understanding the geodynamic puzzle of the southern Mediterranean

The results of an integrated stratigraphic, structural, geophysical, and geochemical study reveal the presence of a crustal discontinuity in western Sicily that, at present, runs roughly N-S along a band from San Vito Lo Capo to Sciacca (SVCS). The boundary between the two zones of this discontinuity is nearly orthogonal to the main thrust propagation of the Sicilian thrust-and-fold belt. The different Permian to Tertiary sedimentary evolution recorded by the two zones appears related to this discontinuity, with thick carbonate platforms in the western sector facing deep-water successions in the eastern one. The presence of Upper Triassic reefs, huge megabreccias bodies, and widespread subm…

SELF-ASSEMBLY OF DEGALACTOSYLATED XYLOGLUCAN FROM TAMARIND SEEDS

Sicilia nord-occidentale: dai Monti di Palermo al trapanese

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The Potential Geosite of the “Libeccio Antico” Quarries: a Sedimentological and Stratigraphic Characterisation of Ornamental Stone from Mt Cocuccio, Custonaci Marble District, Sicily

The Custonaci marble district of western Sicily is known for the production of a valuable ornamental stone that has been, and nowadays is exploited due to its suitable properties and aesthetic qualities. The “Libeccio Antico” was, among the “marbles”, the most appreciated ornamental stone during the Baroque Age (the XVII–XVIII centuries), due to its strong polychrome contrasts from ivory to yellow, green or dark red. This polychrome pattern is the result of dissolution processes that involved an Upper Triassic peritidal limestone. The varicoloured sediments in paleocavities, collapse breccias, paleosols and neptunian dykes that occur in the “Libeccio Antico” represent the peculiar character…

Sedimentology and biostratigraphy of a peritidal succession across the Triassic/Jurassic boundary: Monte Sparagio, north western Sicily

A 490 m thick section of shallowing upward peritidal cycles spanning the Triassic-Jurassic boundary is exposed along the northern slope of Mount Sparagio in the San Vito Lo Capo Peninsula (Western Sicily). A detailed microfacies analysis allowed defining the aspects of cyclic sedimentation of this section and especially the stratigraphic occurrence patterns of benthic foraminifera and algae across the T/J boundary. The lower part of cycles commonly shows medium to low energy subtidal facies, typical of the inner lagoon of the carbonate platform. Subtidal facies such as coral bafflestone in some cycles suggest more open lagoonal conditions (patch reefs), while some higher energy layers such …

Influence of gamma-irradiation on thermally-induced mesoscopic gelation of degalactosylated xyloglucans

Thermoresponsive degalactosylated xyloglucans have been already proposed as in situ gelling scaffolds for tissue engineering, due to their reversible macroscopic thermal gelation at body temperature and biodegradability. The highly branched, hydroxyl group-rich molecular structure renders xyloglucans interesting raw materials also in the form of micro/nanoparticles for application as nanoscalar drug delivery devices in cosmetic and pharmaceutical formulations. Owing to their natural source, xyloglucans show high average molecular weight, broad molecular weight distribution and poor water solubility, as large and compact aggregates usually form via inter-molecular hydrogen bonding. Co-60 gam…

Integration of HVSR measures and stratigraphic constraints for seismic microzonation studies: the case of Oliveri (ME)

Abstract. Because of its high seismic hazard the urban area of Oliveri has been subject of first level seismic microzonation. The town develops on a large coastal plain made of mixed fluvial/marine sediments, overlapping a complexly deformed substrate. In order to identify points on the area probably suffering relevant site effects and define a preliminary Vs subsurface model for the first level of microzonation, we performed 23 HVSR measurements. A clustering technique of continuous signals has been used to optimize the calculation of the HVSR curves. 42 reliable peaks of the H/V spectra in the frequency range 0.6–10 Hz have been identified. A second clustering technique has been applied t…

Degalatosylated xyloglucan hydrogels: influence of irradiation conditions on physico-chemical properties and structure

A Cretaceous carbonate escarpment from Western Sicily (Italy): biostratigraphy and tectono-sedimentary evolution

Abstract The presence of a huge carbonate slope of Cretaceous age is recorded in some imbricated thrust sheets from the Maghrebian fold-and-thrust belt cropping out in northwesternmost Sicily (southern Italy). The sedimentological features of this escarpment, named as the Western Sicily Cretaceous Escarpment (WSCE), have been recently described. The present paper aims to provide a detailed bio-chronostratigraphic characterization of the different facies types that occur in the four lithostratigraphic units spanning the whole slope depositional system. The detailed biostratigraphic analysis and correlation of a number of well-exposed sections allowed to differentiate eight informal biozones …

A regional-scale discontinuity in western Sicily revealed by a multidisciplinary approach: A new piece for understanding the geodynamic puzzle of the southern Mediterranean

The results of an integrated stratigraphic, structural, geophysical, and geochemical study reveal the presence of a crustal discontinuity in western Sicily that, at present, runs roughly N-S along a band from San Vito Lo Capo to Sciacca. The boundary between the two zones of this discontinuity is nearly orthogonal to the main thrust propagation of the Sicilian thrust-and-fold belt. The different Permian to Tertiary sedimentary evolution recorded by the two zones appears related to this discontinuity, with thick carbonate platforms in the western sector facing deepwater successions in the eastern one. The presence of Upper Triassic reefs, huge megabreccia bodies, and widespread submarine vol…

Depositional mechanism of the upper Pliocene-Pleistocene shelf-slope system of the western Malta Plateau (Sicily Channel)

Abstract A high resolution seismic stratigraphic study of the western edge of the Malta Plateau (central Mediterranean Sea) was conducted to reconstruct the depositional mechanisms of the shelf-slope system since the end of the Messinian salinity crisis (MSC; 5.3 Ma). The accurate interpretation of a large grid of variable-resolution seismic reflection profiles (multichannel and Sub Bottom) allows us to identify and map a Plio-Quaternary sedimentary sequence overlying the Messinian evaporites. The stratal pattern of this sequence is the result of a clinoform prograding system that constitutes the internal structure of a sedimentary shelf developed in a ramp about 2° slope with bathymetries …

Processi paleocarsici e geositi: il caso del “libeccio antico” nel distretto marmifero di Custonaci, Sicilia nord-occidentale

Abstract The Upper Triassic strata that crops out along the northern slope of Monte Sparagio, in the Custonaci “marble” district in northwestern Sicily, show an extensive development of dissolution cavities with a very variable shape and dimensions. Several different types of dissolution morphologies can be differentiated from microkarst to giant caverns. The cavities are filled up by polychrome silts or calcite cements or, in the larger caverns, by collapse breccias. The matrix between the collapse breccias is a polychrome silt that gives rise to an attractive ornamental stone, quarried in the past with the name of “Libeccio Antico”. The diagenetic processes that have controlled the format…

Temperature-responsive cellulose-based hydrogels as draw agents in Forward Osmosis

Forward Osmosis is a powerful tool to produce clean water at a low cost if appropriate draw agents and regeneration methods are employed (1). In this frame, stimuli-responsive hydrogels are interesting candidates due to their ability to uptake water and release it under physical stimuli, such as hydrostatic pressure and temperature variations. In particular, temperature-responsive hydrogels that are able to absorb large amount of water at room temperature and release it upon a slight temperature increase are very appealing candidates because they can be regenerated easily and with very low energy consumption (2). Chemical stability and biocompatibility are two further requirements that hydr…

Gelation of degalactosylated xyloglucan from nano to macroscopic scale

Partially degalactosylated xyloglucans are able to form thermo-reversible gels in aqueous solution at physiological temperature. This property makes them very promising materials for tissue engineering. Moreover, due to a highly branched, hydroxyl group-rich molecular structure, xyloglucans are particularly interesting for manufacturing of micro/nanoparticles to be used as nano-scalar delivery devices of active ingredients in cosmetic and pharmaceutical formulations. Here we present results on the temperature-induced self-assembly of degalactosylated xyloglucan at varying polymer concentration from dilute to semi-dilute regime. Our aim is to investigate the gelation mechanism for gaining in…

POLYSACCHARIDE-BASED HYDROGELS FOR MYOCARDIUM REMODELING

An enormous sulfur isotope excursion indicates marine anoxia during the end-Triassic mass extinction

The role of ocean anoxia as a cause of the end-Triassic marine mass extinction is widely debated. Here, we present carbonate-associated sulfate δ34S data from sections spanning the Late Triassic–Early Jurassic transition, which document synchronous large positive excursions on a global scale occurring in ~50 thousand years. Biogeochemical modeling demonstrates that this S isotope perturbation is best explained by a fivefold increase in global pyrite burial, consistent with large-scale development of marine anoxia on the Panthalassa margin and northwest European shelf. This pyrite burial event coincides with the loss of Triassic taxa seen in the studied sections. Modeling results also indica…

Spongy-like porosity in peritidal carbonates: An interaction of cyclic sea-level oscillations, fresh water supply and sediment texture

Abstract This paper focuses upon the analysis of a complex paleokarstic system recorded within uppermost Triassic peritidal cycles in northwestern Sicily. Besides documenting spectacular karstification at the Triassic/Jurassic boundary, it provides an example of stratabound ‘spongy’ or ‘swiss-cheese’ dissolution. On the base of field observations, microfacies analysis, transmitted-light and cathodoluminescence petrography and stable-isotope analyses we put forward an original model for the formation of this peculiar stratabound dissolution. It implies a complex interaction of several controlling factors at the interface between the marine and meteoric diagenetic realms during the relative c…

Temperature-induced self-assembly of degalactosylated xyloglucan at low concentration

Xyloglucan is a natural polysaccharide having a cellulose-like backbone and hydroxyl groups-rich side-chains. In its native form the polymer is water-soluble and forms gel only in presence of selected co-solutes. When a given fraction of galactosyl residues are removed by enzymatic reaction, the polymer acquires the ability to form a gel in aqueous solution at physiological temperatures, a property of great interest for biomedical/pharmaceutical applications. This work presents data on the effect of a temperature increase on degalactosylated xyloglucan dispersed in water at concentration low enough not to run into macroscopic gelation. Results obtained over a wide interval of length scales …

Fracture stratigraphy and oil first migration in Triassic shales, Favignana Island, western Sicily, Italy

This study aims at evaluating the control exerted by fracture stratigraphy and diagenetic processes on oil first migration through an outcropping, mixed carbonate-siliciclastic succession. The present work included results of sedimentological, paleontological, mineralogical, petrographic, structural, and microstructural analyses carried out on organic-rich shales exposed at the Favignana Island of Sicily, Italy. The analyses focus on Upper Triassic yellowish siltstones and greyish laminated dolomitic limestones, which form a 10's of m-thick succession exposed along the westernmost portion of the Sicilian fold-and-thrust belt. The studied succession deposited in a coastal lagoon associated t…

Strutture deformative sindeposizionali nelle calcareniti Pleistoceniche del settore orientale dell'Isola di Favignana (Sicilia, Italia)

Radiation Engineering of Xyloglucan Hydrogels

Xyloglucans (XGs) are interesting substrates for the production of scaffolds for tissue engineering, drug delivery depots and hydrogel dressings, thanks to their ability to gel in appropriate conditions, such as in the presence of hydro-alcoholic solvents or by addition of sugar molecules. Due to their natural source, they are characterized by high average molecular weights and broad molecular weight distributions. High energy irradiation is a suitable tool to reduce polysaccharides molecular weight without a dramatic alteration of the polymer chemical structure and gelation ability. In this work, the effect of the radiation dose on the molecular weight of a XG derived from Tamarind seeds i…

End Triassic karstification of a south Tethyan carbonate platform: the genesis of the “Libeccio Antico” a famous Baroque dimension stone.

Mercury contents and isotope ratios from diverse depositional environments across the Triassic–Jurassic Boundary: Towards a more robust mercury proxy for large igneous province magmatism

Abstract Mercury is gaining prominence as a proxy for large igneous province (LIP) volcanism in the sedimentary record. Despite temporal overlap between some mass extinctions and LIPs, the precise timing of magmatism relative to major ecological and environmental change is difficult to untangle, especially in marine settings. Changes in the relative contents of Hg in sedimentary rocks through time, or ‘Hg anomalies’, can help resolve the timing of LIP activity and marine extinctions. However, major questions remain unanswered about the fidelity of Hg as a proxy for LIP magmatism. In particular, depositional (e.g., redox) and post-depositional (e.g., oxidative weathering) processes can affec…

TEMPERATURE-TRIGGERED MACROSCOPIC GELATION OF IRRADIATED XYLOGLUCANS FOR BIOMEDICAL APPLICATIONS

Positive Sulfate Sulfur Isotope Excursion Indicates Large-Scale Pyrite Burial and Marine Anoxia during the End–Triassic Mass Extinction

The late Rhaetian–early Hettangian transition is characterised by the emplacement of Central Atlantic magmatic province and associated climatic effects, coincident with a severe biotic crisis (~201.5 Ma). The oxygen deficiency in the ocean realm is possibly linked to this significant loss in marine biodiversity. However, direct evidence of contemporaneous development of marine anoxia on a global scale has been lacking and the relationship between oxygen and extinction is unclear. Here we report carbonate-associated sulfate δ34S data from three sections across the Late Triassic–Early Jurassic transition. We find synchronous large positive δ34S shifts with a magnitude of >10‰ in the latest…

Triassic/Jurassic boundary in peritidal carbonates from western Tethys

A carbonate platform from the western margin of the Ionian Tethys has been investigated for biotic and geochemical variations across the Triassic/Jurassic boundary (TJB). The section of Mount Sparagio (north-western Sicily) exposes a peritidal succession of Rhaetian-Hettangian age with a thickness of about 400 m. The peritidal sediments are organized in metre-scale shallowing upward cycles formed by subtidal, intertidal and supratidal facies. Along the section, the subtidal facies vary from bioturbated mud/wackestones with rare mollusc shells, to Megalodont-rich wacke/packstones to, more rarely, coral bafflestones, most likely as response to variations of the accommodation space and water e…

Synthetic and natural polymer nanoparticles as bio-imaging and therapeutic agent vectors

Integration of stratigraphic data with HVSR measures for studies of seismic microzonation: the case of Oliveri (ME)

The seismic microzoning is a technique of analysis of a territory which aims to recognize, at a small scale, the local geological and geomorphologic conditions that may significantly affect the characteristics of the seismic motion, generating stress on structures that could produce permanent and critical effects. In other words, this technique has the objective to predict and evaluate possible site effects as a result of an earthquake. The first phase of the seismic microzoning is the detailed partition of the territory in homogeneous areas with respect to the expected behavior of soils during an earthquake. The seismic micro-zoning is a tool for prevention and reduction of seismic risk pa…

Multi-scale dissolution events in Western-Tethyan peritidal carbonates close to the Triassic/Jurassic boundary

The stratigraphical and sedimentological study of uppermost Triassic-lowermost Jurassic sections of peritidal carbonates, in north-western Sicily, allows to differentiate multi-scale dissolution events that affected the carbonate platform interior during the uppermost Rhaetian. The Triassic cycles show extensive phenomena of stratabound dissolution that can be differentiated in three main types: vug, moldic and “spongy-like”. The dissolution horizons are particularly concentrated in the subtidal members of cycles. The creation of different type of porosity seems to be mainly controlled by the textural characters of the host-rock. In particular the cm-scale bioturbation in muddy sediments, p…

Preparazione di nanoparticelle di xiloglucano degalattosilato per applicazioni biomediche

Acidification processes in a peritidal carbonate succession across the Triassic/Jurassic boundary (Sicily)

For the first time, a correlation between biostratigraphic events and δ13C curve was attempted along an UpperTriassic-Lower Jurassic peritidal limestone succession cropping out in westernmost Sicily. The peritidal carbonates are organized in shallowing upward cycles characterized by subtidal skeletal mudstone to grainstone, intertidal microbial mats and supratidal paleosoils. About 300 meters of this succession covering the Triassic-Jurassic interval were studied in details. On the base of the macro- and microfossil assemblages from the subtidal facies, four informal units have been recognized along the studied section. Unit R1 (at the base, 111 m thick) is dominated by large megalodonts, r…

Temperature-responsive degalactosylated xyloglucans as nanocarriers for the sustained release of hydrophobic drugs

Paleokarstic overprint on the Panormide Carbonate Platform (Sicily)around the T/J boundary

Radiation-Engineering of All Plastic Nanocomposite Films

In recent years, polymer nanocomposites have fascinated scientists, engineers and industrialists on the premise that the creation of new and more performing polymeric materials is possible by the combination of different building blocks with controlled dimensions at the nanoscale. Unfortunately, uniform dispersion of the hetero-phase domains within the plastic matrix or on its surface often fails due to the unfavorable thermodynamics, thus resulting in migration and irreversible aggregation phenomena. In-situ generation of a dispersed hetero-phase within the same polymer matrix or in its precursors increases the chances of achieving a better control of morphology by eliminating the often cr…

Xyloglucan-based hydrogel films for wound dressing: Structure-property relationships

Thin xyloglucan-based hydrogel films have been synthetized and characterized in the prospect of producing wound dressings. Polyvinyl alcohol (PVA) and glycerol (Gro) were added to have an optimal combination of softness, conformability and resilience. Physical hydrogels have been transformed into permanent covalent hydrogels by reaction with glutaraldehyde (GA). Network structure-process-property relationships are discussed on the account of the results of several complementary characterizations: FTIR, rheology, thermal analysis, morphological analysis, moisture retention and swelling measurements. Selected formulations were also subjected to preliminary in vitro cytotoxicity tests. The phy…

Temporal control of xyloglucan self-assembly by radiation-induced degradation

Xyloglucan is a natural polysaccharide present as storage material in seeds and structural materials in the primary cells walls of higher plants. Xyloglucan from tamarind seed is composed of B(1,4)-D-glucan backbone, partially substituted by a-(1,6)-linked xylose units, some of which are B-D-galactosylated at O-2. In its native form the polymer is water-soluble and forms gel in the presence of moderate amounts of alcohols. When a given fraction of galactosyl residues are removed, the polymer acquires the ability to form gels in aqueous solution at physiological temperatures, a property of great interest for biomedical/pharmaceutical applications. Gelation on increasing temperature can be as…

The migration path of Gondwanian dinosaurs toward Adria: New insights from the Cretaceous of NW Sicily (Italy)

Abstract The increasing dinosaur record from Italy questioned classic palaeogeographic scenarios for the Central Mediterranean area and suggest the proximity of landmass areas and a geographical connection between Gondwana and Laurasia during Cretaceous times. Besides several track-sites and exceptionally-preserved specimens (e.g. Scipionyx samniticus), the Italian dinosaur record also consists of isolated bones, among which the bone fragment of a theropod discovered in north-western Sicily. The bone occurs in a shallow-water carbonate succession (i.e. Pizzo Muletta, Palermo Mountains) pertaining to the Panormide Carbonate Platform (PCP). The bone was previously ascribed to the Cenomanian, …

Temporal control of xyloglucan self-assembly into layered structures by radiation-induced degradation

Partially degalactosylated xyloglucan from tamarind seeds (Deg-XG) is a very appealing biopolymer for the production of in situ gelling systems at physiological temperature. In this work, we observe that the morphology of hydrogels evolves towards high degrees of structural organization with time, yielding to dense stacks of thin membranes within 24 h of incubation at 37 °C. We also explore the possibility offered by gamma irradiation of controlling the time scale of this phenomenon, the final morphology and mechanical properties of the system. Structural and molecular modifications of Deg-XG with dose are investigated by FTIR, dynamic light scattering (DLS) and rotational viscosimetry. The…

Studies of network structure and dynamics of e-beam crosslinked PVPs: From macro to nano

Much interest has been paid to develop a variety of radiation-crosslinked hydrated polymeric materials, which swell in water but do not dissolve, as biocompatible materials used for wound healing, drug delivery system, surface-coating material for medically used devices, etc. With the aim of establishing design rules to produce hydrogels of controlled size at the nanoscale and desired internal network structure using conventional electron accelerators and set-ups, here we attempt a description in terms of structural and dynamic properties of polymer networks generated through e-beam irradiation of aqueous solutions of the same model polymer, a commercial grade poly(N-vinyl-pyrrolidone), sub…

A Km-scale Cretaceous slope in western Sicily (Italy)

Cretaceous slopes are well known from many regions of the world, since they are among the most prone depositional systems to host hydrocarbons. As far as Italy, in spite of fully described examples as the Majella and Gargano escarpments, detailed sedimentological and biostratigraphic studies from Sicily are not available, although the presence of slope carbonates of Cretaceous age in northwestern Sicily, is mentioned in several papers dealing with regional geology or geological mapping. The Cretaceous slope carbonates from this area, i.e. the San Vito Lo Capo Peninsula, belong to several thrust sheets of the Maghrebian chain. The stratigraphic setting in these tectonic units allows to recon…

Facies stacking and extinctions across the Triassic–Jurassic boundary in a peritidal succession from western Sicily

An uppermost Triassic–lowermost Jurassic carbonate platform succession, which is 430 m thick, in northwestern Sicily is described with the aim to provide new data on the sedimentological and biological variations across the Triassic–Jurassic boundary in peritidal environments. The studied succession belonged to the rimmed carbonate shelf that developed during the upper Triassic along the margins of the Ionian Tethys. The peritidal sediments consist of metre-scale shallowing-upward cycles formed by subtidal, intertidal and supratidal facies. Three main informal units are differentiated along the section on the basis of the variations recorded by the subtidal facies. The lower and middle unit…

Triasina hantkeni limestones from western Sicily