15 results on '"Stagno, V."'
Search Results
2. In situ investigation of the atomic structure of carbonate-silicate liquids at high pressure-temperature and spectroscopic characterization of the recovered quenched glasses
- Author
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Stopponi, V., primary, D'Arco, A., additional, Kono, Y., additional, Piccirilli, F., additional, Poe, B.T., additional, Lupi, S., additional, Nazzari, M., additional, Pappalardo, L., additional, Marras, G., additional, Zacchigna, M., additional, Manning, C.E., additional, Romano, C., additional, and Stagno, V., additional
- Published
- 2024
- Full Text
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3. Microstructural features assessment of different waterlogged wood species by NMR diffusion validated with complementary techniques
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Stagno, V., Egizi, F., Corticelli, F., Morandi, V., Valle, F., Costantini, G., Longo, S., and Capuani, S.
- Published
- 2021
- Full Text
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4. Extensive oxidizing events recorded by peridotite mantle xenoliths from the Hyblean Plateau: Evidence from combined measurements of ferric iron in spinel with noble gases and fluid inclusions chemistry in olivine
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Marras, G, Stagno, V, Andreozzi, G, Caracausi, A, Cerantola, V, Frezzotti, M, Zacchigna, M, Perinelli, C, Andreozzi, GB, Frezzotti, ML, Marras, G, Stagno, V, Andreozzi, G, Caracausi, A, Cerantola, V, Frezzotti, M, Zacchigna, M, Perinelli, C, Andreozzi, GB, and Frezzotti, ML
- Abstract
The study of the oxidation state of lithospheric mantle-derived rocks allows modelling the deep cycle of volatiles (e.g., C, H, O, N and S) in the Earth's interior, which in turn plays a role in magma genesis, metasomatism and volcanic degassing. At the oxygen fugacity (i.e., fO2) recorded by residual abyssal peridotites, volatile elements like carbon are predicted to be in the immobile form of graphite. However, the compilation of the redox state of worldwide-distributed continental xenoliths shows evidence of their oxidation and refertilization through time by deeply formed subduction-related metasomatic fluids. The analyses of fluid inclusions in mantle-derived minerals like olivine (or pyroxenes) represent a snapshot of the volatile circulation in depth, whose noble gases signature (He, Ar, Ne) is used to identify their possible source. This study aims to reconstruct the origin of mantle metasomatism underneath the Hyblean Plateau (Sicily, Italy) and its redox history through the investigation of spinel-peridotite nodules, combining fO2 estimates with noble gases and fluid inclusions chemistry from hand-picked olivine grains. We analyzed eight mantle xenoliths classified as spinel lherzolites and spinel harzburgites from the Valle Guffari (Hyblean Plateau, Sicily). The calculated logfO2 is higher than that of most cratonic xenoliths worldwide ranging between 0.28 and 1.27 log units above to the fayalite-magnetite-quartz (FMQ) reference buffer. Micro-Raman measurements on olivine grains with dendritic trails of (metasomatic) fluid inclusions reveal an assemblage made of Mg-Ca carbonates ± sulfide ± elemental sulfur ± CO2 in the most reduced sample, and Mg-Ca carbonates ± sulfates ± CO2 in the most oxidized sample, the latter associated with a silicate glass and (secondary) hydrous phases. Both assemblages are taken as evidence of the product of crystallization of deeply originated volatile-bearing silicate melts. Analyses of He, Ar, and Ne in olivine grains confi
- Published
- 2023
5. Phlogopite-pargasite coexistence in an oxygen reduced spinel-peridotite ambient
- Author
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Bonadiman C.[1, 2, Brombin V.[1, Andreozzi G.B.[4], Benna P.[5], Coltorti M.[1], Curetti N.[5], Faccini B.[1], Merli M.[6], Pelorosso B.[1], Stagno V.[4], Tesauro M.[7, Pavese A.[5], Tectonics, Bonadiman C., Brombin V., Andreozzi G.B., Benna P., Coltorti M., Curetti N., Faccini B., Merli M., Pelorosso B., Stagno V., Tesauro M., Pavese A., Bonadiman, C., Brombin, V., Andreozzi, G. B., Benna, P., Coltorti, M., Curetti, N., Faccini, B., Merli, M., Pelorosso, B., Stagno, V., Tesauro, M., and Pavese, A.
- Subjects
010504 meteorology & atmospheric sciences ,Science ,phlogopite ,Geochemistry ,engineering.material ,amphibole ,010502 geochemistry & geophysics ,01 natural sciences ,Article ,Mantle (geology) ,NO ,upper mantle ,Mineral redox buffer ,Ultramafic rock ,geotherm ,Metasomatism ,General ,Amphibole ,Petrology ,0105 earth and related environmental sciences ,Peridotite ,model ,Multidisciplinary ,metasomatism ,phlogopite-pargasite ,Chemistry ,mantle xenoliths ,Pargasite ,Mineralogy ,engineering ,Phlogopite ,Medicine ,mantle xenolith - Abstract
The occurrence of phlogopite and amphibole in mantle ultramafic rocks is widely accepted as the modal effect of metasomatism in the upper mantle. However, their simultaneous formation during metasomatic events and the related sub-solidus equilibrium with the peridotite has not been extensively studied. In this work, we discuss the geochemical conditions at which the pargasite-phlogopite assemblage becomes stable, through the investigation of two mantle xenoliths from Mount Leura (Victoria State, Australia) that bear phlogopite and the phlogopite + amphibole (pargasite) pair disseminated in a harzburgite matrix. Combining a mineralogical study and thermodynamic modelling, we predict that the P–T locus of the equilibrium reaction pargasite + forsterite = Na-phlogopite + 2 diopside + spinel, over the range 1.3–3.0 GPa/540–1500 K, yields a negative Clapeyron slope of -0.003 GPa K–1 (on average). The intersection of the P–T locus of supposed equilibrium with the new mantle geotherm calculated in this work allowed us to state that the Mount Leura xenoliths achieved equilibrium at 2.3 GPa /1190 K, that represents a plausible depth of ~ 70 km. Metasomatic K-Na-OH rich fluids stabilize hydrous phases. This has been modelled by the following equilibrium equation: 2 (K,Na)-phlogopite + forsterite = 7/2 enstatite + spinel + fluid (components: Na2O,K2O,H2O). Using quantum-mechanics, semi-empirical potentials, lattice dynamics and observed thermo-elastic data, we concluded that K-Na-OH rich fluids are not effective metasomatic agents to convey alkali species across the upper mantle, as the fluids are highly reactive with the ultramafic system and favour the rapid formation of phlogopite and amphibole. In addition, oxygen fugacity estimates of the Mount Leura mantle xenoliths [Δ(FMQ) = –1.97 ± 0.35; –1.83 ± 0.36] indicate a more reducing mantle environment than what is expected from the occurrence of phlogopite and amphibole in spinel-bearing peridotites. This is accounted for by our model of full molecular dissociation of the fluid and incorporation of the O-H-K-Na species into (OH)-K-Na-bearing mineral phases (phlogopite and amphibole), that leads to a peridotite metasomatized ambient characterized by reduced oxygen fugacity.
- Published
- 2021
6. A multi-analytical study of architectural fragments from the Marzamemi II 'Church Wreck'
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Mirkovic, N., Di Fazio, M., De Vito, C., Ciccola, A., Capuani, S., Stagno, V., and Medeghini, L.
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church wreck ,nmr, green thessalian stone ,green thessalian stone ,nmr - Published
- 2022
7. Iron oxidation state in garnet and clinopyroxene inclusions in E-type diamonds from Udachnaya
- Author
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Marras, G., Mikhailenko, D., Dominijanni, S., Logvinova, A., Mccammon, C. A., and Stagno, V
- Published
- 2022
8. The constant oxidation state of Earth's mantle since the Hadean.
- Author
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Zhang F, Stagno V, Zhang L, Chen C, Liu H, Li C, and Sun W
- Abstract
Determining the evolutionary history of mantle oxygen fugacity (fo
2 ) is crucial, as it controls the fo2 of mantle-derived melts and regulates atmospheric composition through volcanic outgassing. However, the evolution of mantle fo2 remains controversial. Here, we present a comprehensive dataset of plume-derived komatiites, picrites, and ambient mantle-derived (meta)basalts, spanning from ~3.8 Ga to the present, to investigate mantle thermal and redox states evolution. Our results indicate that fo2 of both mantle plume-derived and ambient mantle-derived melts was lower during the Archean compared to the post-Archean period. This increase in the fo2 of mantle-derived melts over time correlates with decreases in mantle potential temperature and melting depth. By normalizing fo2 to a constant reference pressure (potential oxygen fugacity), we show that the fo2 of both the mantle plume and ambient upper mantle has remained constant since the Hadean. These findings suggest that secular mantle cooling reduced melting depth, increasing the fo2 of mantle-derived melts and contributing to atmospheric oxygenation., (© 2024. The Author(s).)- Published
- 2024
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9. Multi-Technique Assessment of Chelators-Loaded PVA-Borax Gel-like Systems Performance in Cleaning of Stone Contaminated with Copper Corrosion Products.
- Author
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Giuliani L, Genova C, Stagno V, Paoletti L, Matulac AL, Ciccola A, Di Fazio M, Capuani S, and Favero G
- Abstract
Currently, one of the most important challenges for the conservation of stone artworks is the removal of metal corrosion products on their surfaces. Traditional cleaning methods, which typically involve the application of aqueous solutions containing chelating agents capable of complexing these metal ions, have shown some weaknesses. These weaknesses become apparent when such methods are applied to statues and other vertical surfaces or when aiming to limit the cleaning process to a specific area with controlled application times. Furthermore, the porosity of the stone surface plays a role concerning the cleaning efficiency. To address these issues, chelating agents can be incorporated into gel-like materials. This study is a proof of concept to evaluate the cleaning efficacy of various gel formulations composed of polyvinyl alcohol (PVA), borax (B), and agarose (AG), loaded with two chelators: ethylenediaminetetraacetic acid (EDTA) and potassium sodium tartrate (PST or Rochelle salt). Three types of carbonate stones (travertine, Lecce stone, and Carrara marble) characterized by different porosities were artificially stained with copper sulphates and treated with the different PVA-B-AG formulations. The effectiveness of the treatment was directly monitored on the stones using a multi-technique approach that included scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and non-invasive portable nuclear magnetic resonance (NMR). Additionally, the rheological properties of the gels were investigated, and the Fourier transform infrared attenuated total reflection spectroscopy (FTIR ATR) was used to analyse the chemical structure of the gel before and after treatment, aiming to understand the changes induced by the cleaning process.
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- 2024
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10. Characterization of CuAg Alloys with Low Ag Concentrations.
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Mosesso L, Macis S, D'Arco A, Marcelli A, Notargiacomo A, Pea M, Spataro B, Stagno V, and Lupi S
- Abstract
Copper-based alloys designed to combine high electronic and thermal conductivities with high mechanical strength find a wide range of applications in different fields. Among the principal representatives, strongly diluted CuAg alloys are of particular interest as innovative materials for the realization of accelerating structures when the use of high-gradient fields requires increasingly high mechanical and thermal performances to overcome the limitations induced by breakdown phenomena. This work reports the production and optical characterization of CuAg crystals at low Ag concentrations, from 0.028% wt to 0.1% wt, which guarantee solid solution hardening while preserving the exceptional conductivity of Cu. By means of Fourier Transform Infrared (FTIR) micro-spectroscopy experiments, the low-energy electrodynamics of the alloys are compared with that of pure Cu, highlighting the complete indistinguishability in terms of electronic transport for such low concentrations. The optical data are further supported by Raman micro-spectroscopy and SEM microscopy analyses, allowing the demonstration of the full homogeneity and complete solubility of solid Ag in copper at those concentrations. Together with the solid solution hardening deriving from the alloying process, these results support the advantage of strongly diluted CuAg alloys over conventional materials for their application in particle accelerators.
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- 2024
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11. Evaluation of the efficacy of micro-Magnetic Resonance Imaging compared with light microscopy to investigate the anatomy of modern and ancient waterlogged wood.
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Stagno V, Moricca C, Sadori L, Dell'Aglio E, Reale R, and Capuani S
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- Magnetic Resonance Imaging, Archaeology methods, Wood, Microscopy
- Abstract
Light microscopy is the conventional method used to investigate wood anatomy, identify the wood taxon, and assess its conservation state. It generally requires the mechanical cut of thin sections from a sample to obtain informative images. When dealing with wooden artworks or ancient remains (e.g., archaeological waterlogged wood), it is important to avoid sample destruction. In this work the efficacy of micro-magnetic resonance imaging (μ-MRI) to investigate the anatomy of waterlogged wood is assessed in comparison with light microscopy. Images along the three anatomical directions (transverse, tangential and radial) of six modern wood species and one archaeological specimen of waterlogged wood (from the Neolithic site "La Marmotta") were obtained both by μ-MRI and light microscopy. μ-MRI images were acquired virtually selecting 2D slices along the three wood anatomical directions. A 3D reconstruction was derived from 2D μ-MRI images. Conventional light microscopy histology was obtained by manually cutting thin sections. To the best of our knowledge, this is the first study in which high-resolution MR images and light microscopy images of the three anatomical directions of seven wood species are compared. The non-destructive μ-MRI approach allows to investigate the 2D and 3D topological organization of the whole waterlogged wood sample up to a resolution of 8 μm. Although the optical microscope attains higher image resolutions and remains superior in the observation of wood diagnostic characters, multi-parametric μ-MRI provides physiological investigation complementary to light microscopy, giving information concerning both a single section and the whole volume of the sample. The presented study may represent a starting point for further improvements of μ-MRI techniques applied to the non-destructive investigation of waterlogged wood samples, especially those of interest for cultural heritage., (Copyright © 2023 Elsevier Inc. All rights reserved.)
- Published
- 2023
- Full Text
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12. Cubic Fe-bearing majorite synthesized at 18-25 GPa and 1000 °C: implications for element transport, subducted slab rheology and diamond formation.
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Stagno V, Bindi L, Bonechi B, Greaux S, Aulbach S, Irifune T, Lupi S, Marras G, McCammon CA, Nazzari M, Piccirilli F, Poe B, Romano C, and Scarlato P
- Abstract
The chemistry and mineralogy of slabs subducted into lower mantle control slab rheology and impact the deep volatile cycle. It is known that the metamorphism of little-altered oceanic crust results in eclogite rocks with subequal proportions of garnet and clinopyroxene. With increasing pressure, these minerals react to stabilize pyrope-rich tetragonal majoritic garnet. However, some eclogites contain higher proportions of omphacitic clinopyroxene, caused by Na- and Si-rich metasomatism on the ocean floor or during subduction. The mineralogy of such eclogites is expected to evolve differently. Here, we discuss the results of the crystallization products of omphacitic glass at ~ 18 and ~ 25 GPa and 1000 °C to simulate P-T regimes of cold subduction. The full characterization of the recovered samples indicates evidence of crystallization of Na-, Si-rich cubic instead of tetragonal majorite. This cubic majorite can incorporate large amounts of ferric iron, promoting redox reactions with surrounding volatile-bearing fluids and, ultimately, diamond formation. In addition, the occurrence of cubic majorite in the slab would affect the local density, favoring the continued buoyancy of the slab as previously proposed by seismic observations. Attention must be paid to omphacitic inclusions in sublithospheric diamonds as these might have experienced back-transformation from the HP isochemical cubic phase., (© 2023. Springer Nature Limited.)
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- 2023
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13. Experimental measurements of the viscosity and melt structure of alkali basalts at high pressure and temperature.
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Bonechi B, Stagno V, Kono Y, Hrubiak R, Ziberna L, Andreozzi GB, Perinelli C, and Gaeta M
- Abstract
Volcanic eruptions are shallow phenomena that represent the final stage of density- and viscosity- driven processes of melt migration from source rocks at upper mantle depths. In this experimental study, we investigated the effect of pressure (0.7-7.0 GPa) and temperature (1335-2000 °C) on the viscosity and the atomic melt structure of a synthetic anhydrous primitive alkaline basalt, an analogue of the pre-eruptive magma that likely feeds the Campi Flegrei Volcanic District at present day. Obtained viscosities (0.5-3.0 Pa s), mobility (0.1-0.4 g cm
3 Pa-1 s-1 ) and ascent velocity (1.5-6.0 m yr-1 ) are presented to support geochemical and geophysical observations of Campi Flegrei as a critical volcanic district currently undergoing gradual magma recharge at depth., (© 2022. The Author(s).)- Published
- 2022
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14. Non-Invasive Assessment of PVA-Borax Hydrogel Effectiveness in Removing Metal Corrosion Products on Stones by Portable NMR.
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Stagno V, Ciccola A, Curini R, Postorino P, Favero G, and Capuani S
- Abstract
The cleaning of buildings, statues, and artworks composed of stone materials from metal corrosion is an important topic in the cultural heritage field. In this work the cleaning effectiveness of a PVA-PEO-borax hydrogel in removing metal corrosion products from different porosity stones has been assessed by using a multidisciplinary and non-destructive approach based on relaxation times measurement by single-sided portable Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), and Raman Spectroscopy. To this end, samples of two lithotypes, Travertine and Carrara marble, have been soiled by triggering acidic corrosion of some copper coins in contact with the stone surface. Then, a PVA-PEO-borax hydrogel was used to clean the stone surface. NMR data were collected in untreated, soiled with corrosion products, and hydrogel-cleaned samples. Raman spectroscopy was performed on PVA-PEO-borax hydrogel before and after cleaning of metal corrosion. Furthermore, the characterization of the dirty gel was obtained by SEM-EDS. The combination of NMR, SEM-EDS and Raman results suggests that the mechanism behind the hydrogel cleaning action is to trap heavy metal corrosion products, such as Cu
2+ between adjacent boron ions cross-linked with PVA. Moreover, the PVA-PEO-borax hydrogel cleaning effectiveness depends on the stone porosity, being better in Carrara marble compared to Travertine.- Published
- 2021
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15. Natural Fe-bearing aluminous bridgmanite in the Katol L6 chondrite.
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Ghosh S, Tiwari K, Miyahara M, Rohrbach A, Vollmer C, Stagno V, Ohtani E, and Ray D
- Abstract
Bridgmanite, the most abundant mineral of the Earth's lower mantle, has been reported in only a few shocked chondritic meteorites; however, the compositions of these instances differ from that expected in the terrestrial bridgmanite. Here, we report the first natural occurrence of Fe-bearing aluminous bridgmanite in shock-induced melt veins within the Katol L6 chondrite with a composition that closely matches those synthesized in high-pressure and temperature experiments over the last three decades. The Katol bridgmanite coexists with majorite and metal-sulfide intergrowths. We found that the natural Fe-bearing aluminous bridgmanite in the Katol L6 chondrite has a significantly higher Fe
3+ /ΣFe ratio (0.69 ± 0.08) than coexisting majorite (0.37 ± 0.10), which agrees with experimental studies. The Katol bridgmanite is arguably the closest natural analog for the bridgmanite composition expected to be present in the Earth's lower mantle. Textural observations and comparison with laboratory experiments suggest that the Katol bridgmanite formed at pressures of ∼23 to 25 gigapascals directly from the chondritic melt generated by the shock event. Thus, the Katol L6 sample may also serve as a unique analog for crystallization of bridgmanite during the final stages of magma ocean crystallization during Earth's formation., Competing Interests: The authors declare no competing interest.- Published
- 2021
- Full Text
- View/download PDF
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