Dipartimento di Biologia, Ecologia e Scienze della Terra - Tesi di dottorato

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Questa collezione raccoglie le Tesi di Dottorato afferenti al Dipartimento Dipartimento di Biologia, Ecologia e Scienze della Terra dell'Università della Calabria.

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Author: search.filters.author.Pantano, Pietro SalvatoreHas files: Yes

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    Stima della produzione solida in bacini idrografici con differenti caratteristiche mediante l'applicazione del modello EPM
    (2017-07-12) Vacca, Carmine; Pantano, Pietro Salvatore; Dominici, Rocco; Mao, Luca
    In order to increase the knowledge of sediment production and transport at the river basin scale, the research aims at the creation of a GIS project based on the multiparametric equation related to the potential erosion model EPM (Gavrilovic, 1988). The GIS allows the remote sensing data (DEM, satellite images, aerial photos etc.) to be associated with the informations detected on field. The interaction between different thematic layers allows to obtain, in an analytical way, a cartographic and a numeric output as database. These data storage are easily consulted and implemented, making the use of GIS essential for proper spatial planning. Starting from this methodological assumption, the EPM Model was applied for a certain number of catchment areas, in different geographic contexts, to better characterize the input data as a function of the output data. The output model has been calibrated and validated by comparing the experimental data obtained with real estimates of sediment transport, suspend load and bed load, of an Alpine Basin (Rio Cordon) and a Chilean Basin (Estero Morales), and with estimates of silting of dams, located in the Alpine Arc and along the Southern Apennines. The implementation of a connectivity index (degree of linkage between sediment sources and downstream areas) has led to the individuation of the volume of material that can feed an hypothetical coastal physiographic unit or can cause problems to an artificial reservoir. This more efficient model was applied to three test basin located in the Ionian (F.ra Saraceno e Stilaro) and Tyrrhenian (F.ra Sfalassà) Calabria areas. The versatility of GIS platforms and the data obtained from the EPM Model enable us to obtain a connective tool easily developable through the time, which permits the interaction between individuals and institutions in order to perform a proper management of the areas particularly vulnerable from the hydrogeological point of view
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    Some Calabrian stones as building materials: characterization, durability and use suggestions
    (2017-07-11) Forestieri, Giulia; Pantano, Pietro Salvatore; Ponte, Maurizio; Campolongo, Alessandro; De Francesco, Anna Maria; De Buergo Ballester, Mónica Alvarez
    The aim of this PhD thesis is to provide new scientific data regarding the use of certain Calabrian stones as building materials. This investigation included specific local stones used by the most important schools of Stonemasons of Calabria, in particular in the Cosenza Province; focusing on how properties of different building materials have influenced the figurative and architectural models. In this study, stones commonly used as building materials are selected according to two important criteria: 1. The large employment of these materials in the past as building and decorative elements. Studying the use of selected stones in the centuries assists in identifying four lithotypes largely used by the most important Calabrian Schools of Stonemasons in the Cosenza Province: • San Giovanni in Fiore granite - in the Sila area by the school of San Giovanni in Fiore and famous for its severe style due to “Joachim of Fiore” rules, and to material hardness. • Grisolia stone – known as “gold stone” for its gold inclusions; limestone that represents the principal building material of the majority of the historical centers of the northern Tyrrhenian part of the Calabrian region and a small part of the Basilicata region. • San Lucido stone - biocalcarenite known in the past as “biancolella”; employed as a building material in the historical center of San Lucido and in the historical center of Cosenza, to build structural and decorative elements such as portals and arches. • Fuscaldo stone - sandstone commercially known as “sweet stone” and utilized by artisans of the 14th century school of Fuscaldo; principally known for the construction of portals of noble palaces, built in the Spanish “plateresco” (plateresque) style for ornamental elements. 2. Lithotypes belonging to the different active and non-active important quarry areas of the Cosenza Province. Also taken into account is the possibility that these quarries may still be exploited for a local limited use, or a possible diffusion on a large scale out of the Region. Special attention is dedicated to the characterization, durability, and to the building techniques employed in the past of the selected stones. The petrophysical and mechanical characterization of these stones are performed by means of studying the petrographic characteristics, chemical and mineralogical composition, hydric properties; and the physical and mechanical behavior, with special attention to possible anisotropies. For this purpose, laboratory and non-destructive tests on quarry samples complying the current standards for “natural stones” and for the “conservation of cultural property” are performed. Salt crystallization and freeze-thaw tests are performed to assess the durability of the stones and to relate the investigated stone properties with their behavior towards decay agents. Among all the investigated lithotypes, San Giovanni in Fiore granite and Grisolia stone result the stones with a better mechanical and resistance behavior than the other lithotypes. In terms of durability, they are the most durable stones, and in terms of mechanical strength resistance, the strongest stones, both suitable for indoor and outdoor uses. But, petrographically, in the case of San Giovanni in Fiore granite, the oriented sets of microcracks demonstrate that microcracks influence the physical and mechanical behavior of this lithotype. In fact, comparing San Giovanni in Fiore granite with other similar granites, this stone presents worse properties and an anisotropic strength behavior, connected to the different orientation of its intracrystalline and intercrystalline microcracks. San Lucido calcarenite is classified as a stone with better mechanical features than petrophysical and hydric properties, so, the recommended use is for structural purposes, especially inside rather than for ornamental and external uses, in general where salts are not present. Concerning both petrohysical-mechanical properties and durability, Fuscaldo sandstone is the stone with the worst behavior, if compared with the other investigated lithotypes. Its mineralogical composition connected to the susceptibility of some minerals, its high open porosity, the presence of a lot of micropores, its anisotropic hydric behavior, the high degree of ultrasonic anisotropy and its low mechanical strengths, makes this stone sensitive to decay processes and the recommendation is to use this stone for inside purposes and where no salts are present. Results demonstrate that anisotropy and porosity are the main influencing factor in the stone behavior and durability. The way in which stones are positioned can avoid decay processes and improve their petrophysical-mechanical properties. In particular, it is suggested positioning the most anisotropic lithotypes (e.g. Fuscaldo sandstone) with the Z-direction parallel to the loading direction to obtain higher strengths and, simultaneously, to minimize water absorption. Moreover the pore structure, the pore-size distribution, the open porosity and the hydric behavior influence directly the stone resistance in front of decay agents. Microporous stones (e.g. Fuscaldo sandstone) or stones with high capillary coefficients (e.g. San Lucido calcarenite) have been classified as more susceptible to decay agents. Furthermore, an attempt is made to consider possible modifications of current standards and performed non-destructive techniques, strictly focusing on the applied methods and the tested material of this research. In conclusion, all obtained results indicate the optimum use and the best methodology to perform, for the four investigated stones as building materials with regards to the stones’ properties and with particular attention to different behaviors towards the anisotropy
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    Petrographic and geochemical study of the Jarosite bearing layers of Aeolian Islands
    (2014-11-26) Khyabani, Fahimeh Ryazi; Pantano, Pietro Salvatore; Barca, Donatella; Crisci, Gino Mirocle
    A thin reddish-brown Surface Coating (SC) layer has diffusely covered many outcrops of Vulcano Island (one of the Aeolian Islands), located in the Tyrrhenian Sea, south Italy. Vulcano, in the last 120ka has been subjected to volcanic activities including both eruptions (pyroclastic and lava types in shoshonitic and leucite-tephritic series) and fumarolic degassing. The SC that has been formed on almost all these lithologies appears as a reddish (sometimes pinkish) brown glass-like rind with a greasy luster which adheres to substratum and fills and completely seals its surface irregularities. The precise formation process of the SC is what we have tried to model in the present work. The SC in Vulcano, like other active volcanic precincts, includes amorphous silica associated with a sulfate phase as jarosite mineral. Jarosite as a basic hydrous sulfate of potassium and iron is the head member of jarosite subgroup. Under the microscope, SC is consisted of a micro laminated layer (less than 1μm to 7μm in thickness) which is composed of alternative dark and light laminae. The light laminae are composed of jarosite, while the darker ones are made of almost pure silica. In many cases of the SC, the laminae encompass lenticular areas containing coarser mineral crystals and noticeable number of glass shards, very fresh to altered in different grades, within an inexplicit background. The relations between all these components (laminated portion and the trapped area between different subsets of laminae) creates some particular textures such as lentic/eye texture; convoluted texture (flow of laminae); branching, rejoining, and tee-shaped perpendicular junctions of the laminae. These particular textures are quite comparable to the patterns of Liesegang Bands in the microscopic scale. Permeability of the rock; the presence of reactants such as oxygen, iron, and sulfur; and a potential fluid to be supersaturated are required factors for developing the Liesegang bands. The porous surface of the pyroclastic deposits of Vulcano can be exposed to the acidic fluids (produced by the interaction between water and fumarolic gases) and the availability of the iron and sulfur can provide the suitable condition to form the Liesegang patterns.
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    Microbial mediation in the formation and alteration of minerals in shallow marine environments (Southern Calabria, Italy)
    (2017-11-26) Cefalà, Massimo; Pantano, Pietro Salvatore; Perri, Edoardo
    This work wants to investigate the role that microorganisms have in the alteration and precipitation of minerals, in particular Ca-carbonates, on natural and artefact rocks of archaeological interest in shallow marine environments. This finds numerous applications in the recognizing of the abiotic vs. biotic nature of neoformed minerals, such as in the reconstruction of depositional palaeoenvironment, in astrobiology and in medicine. In addition, nanostructured microbially induced minerals have several technical application varying from bioconservation, bioremediation, biogrouting to biomedic. Furthermore, the knowledge of such complex interaction between bacterial communities and hard substrates is essential for the preservation and the valorization in situ of underwater cultural heritage, which represents a particularly important element in the history of peoples. For this purpose, several key-samples of natural and artifact rocks, have been collected in Santa Maria di Ricadi bay and in the archaeological submerged park of Monasterace, respectively sited on the Tyrrhenian and Ionian coast of Southern Calabria. Optical and scanning electron microscopy (SEM) have been used for micro- and nano-scale investigation of the role of microorganisms in the precipitation and alteration of minerals. Observations showed that biofilms are characterized by: (1) Skeletal elements, such as red algae, bryozoan, polychaete, bivalves and diatoms; (2) bacteria such as cocci, bacilli, spirochaete, filamentous bacteria, often associated with organic matter remains which result sometimes mineralized; (3) Neo-formed Cacarbonate and pyrite minerals; (4) bioerosion elements, such as grooves and boreholes Neo-formed Ca-carbonate minerals occur in Monasterace biofilms as sheet deposits, triads or dumbbell- to spherical-shaped crystals; whereas in Santa Maria di Ricadi as aphanitic and peloidal deposits. All these deposits result made up by an assemblage of nanospheres, varying in diameter from 50 to 200 nm, tightly clotted together. The co-existence of degraded EPS and bacteria, strictly associated with Cacarbonate nanospheres, implies that the organic matter and the microbial metabolism played a fundamental role in the precipitation of these minerals. Moreover, in Monasterace biofilms, framboidal pyrite occur both in rock fracture up to 2 mm below rock surface and within cavities of encrusting red algae. The presence of framboidal pyrite and dumbbell- to spherical- shaped crystals imply they formed in anoxic environment by sulphate reducers bacteria. As regards bioerosion products, these results formed by epilithic, endolithic and euendolithic organisms. In particular, in Ca-carbonate deposits forming part of Santa Maria di Ricadi rock samples, an intricate net of grooves is produced by cyanobacterium M. testarum. All these elements suggest that biofilms are complex systems formed by different biotic processes occurred both in oxic and anoxic conditions. Epilithic and endolithic microorganisms resulted capable to modify chemical and physical microconditions leading to the precipitation and alteration of diverse rocky materials, in particular Calcium carbonate, in shallow marine environments.