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Della Ventura, Giancarlo
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Della Ventura, Giancarlo
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Della Ventura, G.
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- PublicationRestrictedPhase transition induced by solid solution: The Ca-Mg substitution in richteritic amphiboles(2010)
; ; ; ; ; ; ; ; ;Iezzi, G.; Dipartimento DIGAT, Università G.d'Annunzio, Chieti, Italy ;Della Ventura, G.; Dipartimento di Scienze Geologiche, Università di Roma Tre, Roma,Italy ;Tribaudino, M.; Dipartimento di Scienze della Terra, Università di Parma, Parma, Italy ;Nemeth, P.; Department of Surface Modifications and Nanostructures, Chemical Research Center of the Hungarian Academy of Sciences,Budapest, Hungary ;Margiolaki, I.; European Synchrotron Radiation Facility (ESRF),Grenoble, France ;Cavallo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Gaillard, F.; ISTO, Université d’Orleans Campus Geosciences,Orléans, France ;Beherns, H.; Institut of Mineralogy, University of Hannover,Hannover, Germany; ; ; ; ; ; ; Eleven compositions along the join Na(NaMg)Mg5Si8O22(OH)2-Na(NaCa)Mg5Si8O22(OH)2 (“magnesiorichterite”-richterite) have been synthesized at T = 800–850 °C and PH2O = 0.35–0.5 GPa. The run products have been characterized by electron probe microanalysis (EPMA), synchrotron and conventional X-ray powder diffraction (XRPD), Fourier transformed infrared (FTIR) spectroscopy, and selected area electron diffraction (SAED-TEM). Nominally, the chemical variation along the join can be expressed as BMgxBCa1–x with 0 ≤ x ≤ 1. A combination of EPMA and FTIR data in the OH-stretching region show that a complete solid solution is obtained under the conditions used. Nevertheless, a slight deviation from the nominal compositions involving a limited loss of Na at A and B sites, balanced by an increase of Ca at the B site, is present. Several indications of a displacive and coelastic P21/m → C2/m transformation induced by the Ca-Mg chemical substitution are observed. The phase transition occurs at B-site composition (Xc) close to B(Na1Mg0.7Ca0.3). C2/m samples with a Ca content of 0.34, 0.45, and 0.54 apfu show a significant strain tail related to local compositional inhomogeneities. This residual strain disappears as the amount of BCa significantly increases with respect to that of BMg. The transformation behavior observed here mirrors that of pyroxenes along the join diopside (CaMgSi2O6)-enstatite (Mg2Si2O6). The cell parameters of amphiboles with CMg5, TSi8, and W(OH)2 and variable A- and B-site populations follow almost linear and continuous trends, indicative of small amounts of spontaneous strain accompanying these monoclinic phase transitions and the absence of significant miscibility gaps among different amphibole groups when quenched from higher temperatures of crystallization.149 21 - PublicationOpen AccessNeutron and XRD Single-Crystal Diffraction Study and Vibrational Properties of Whitlockite, the Natural Counterpart of Synthetic Tricalcium PhosphateA crystal chemical investigation of a natural specimen of whitlockite, ideally Ca9Mg(PO4)6[PO3(OH)], from Palermo Mine (USA), was achieved by means of a combination of electron microprobe analysis (EMPA) in WDS mode, single‐crystal neutron diffraction probe (NDP) and single‐crystal X‐ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The crystal‐chemical characterization resulted in the empirical formula (Ca8.682Na0.274Sr0.045)Σ9.000(Ca0.034□0.996)Σ1.000(Mg0.533Fe2+0.342Mn2+0.062Al0.046)Σ0.983(P1.006O4)6[PO3(OH0.968F0.032)Σ1.000]. Crystal‐structure refinement, in the space group R3c, converged to R1 = 7.12% using 3273 unique reflections from NDP data and to R1 = 2.43% using 2687 unique reflections from XRD data. Unit cell parameters from NDP are a = 10.357(3) Å, c = 37.095(15) Å and V = 3446(2) Å3, and from XRD, the parameters are a = 10.3685(4) Å, c = 37.1444(13) Å and V = 3458.2(3) Å3. NDP results allowed a deeper definition of the hydrogen‐bond system and its relation with the structural unit [PO3(OH)]. The FTIR spectrum is very similar to that of synthetic tricalcium phosphate Ca3(PO4)2 and displays minor band shifts due to slightly different P‐O bond lengths and to the presence of additional elements in the structure. A comparison between whitlockite, isotypic phases from the largest merrillite group, and its synthetic counterpart Ca3(PO4)2 is provided, based on the XRD/NDP and FTIR results.
30 12 - PublicationRestrictedReal-time quantitative detection of styrene in atmosphere in presence of other volatile-organic compounds using a portable deviceExposure to styrene is a major safety concern in the fibreglass processing industry. This compound is classified by the International Agency for Research on Cancer as a possible human carcinogen. Several types of analytical equipment exist for detecting volatile organic compounds (VOCs) in the atmosphere; however, most of them operate ex-situ or do not provide easy discrimination between different molecules. This work introduces an improved and portable method based on FTIR spectroscopy to analyse toxic gaseous substances in working sites down to a concentration of less than 4 ppm. Styrene and a combination of VOCs typically associated with it in industrial processes, such as acetone, ethanol, xylene and isopropanol, have been used to calibrate and test the methodology. The results demonstrate that the technique offers the possibility to discriminate between different gaseous compounds in the atmosphere with a high degree of confidence and obtain very accurate quantitative information on their concentration, down to the ppm level, even when different VOCs are present in a mixture.
37 43 - PublicationRestrictedA CO2-rich magma source beneath the Phlegraean Volcanic District (Southern Italy):(2011-06-13)
; ; ; ; ; ; ; ; ;Mormone, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Piochi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Bellatreccia, F.; Dipartimento di Scienze Geologiche, Università Roma Tre, Roma, Italy ;De Astis, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Moretti, R.; Centro Interdipartimentale di Ricerca in Ingegneria Ambientale (CIRIAM) & Dipartimento di Ingegneria Civile, Seconda Università degli Studi di Napoli, Aversa (CE), Italy ;Della Ventura, G.; Dipartimento di Scienze Geologiche, Università Roma Tre, Roma, Italy ;Cavallo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Mangiacapra, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; ; ; We present a study of olivine-hosted glass/melt inclusions (MIs) in the most primitive rocks erupted at Procida Island, within the Phlegraean Volcanic District (PVD), Southern Italy. MIs were analyzed by combined Scanning Electron Microscopy coupled with Energy Dispersive X-ray-detectors, Wavelength Dispersive X-rayequipped Electron Microprobe and Fourier Transform Infrared (FT-IR) Spectroscopy; notably, the novel Focal- Plane-Array mode provided high-resolution FT-IR images evidencing the distribution of the C–H–O species across samples. Olivines range in composition from Fo85 to Fo90, do not show chemical zoning and are totally anhydrous. The majority of the MIs are glassy, while only few are completely crystallized. Some MIs, however, show the occurrence of crystal nuclei, i.e., nano- to micro-sized pyroxenes and oxides, and appear as lowcrystallized MIs. The glass of crystal-free and low-crystallized MIs shows K-affinity and a compositional range along the basalt, trachy-basalt, shoshonite, tephrite basanite and phono-tephrite array. H2O and CO2 contents up to 2.69 wt.% and 2653 ppm, respectively, define a major degassing trend with small isobaric deviations. The collected data allow recalculating entrapment pressures from ~350 MPa to b50 MPa and suggest that the magma ascent was dominated by degassing. Crystallization was aminor process, likely also consequent to local CO2-fluxing. Mingling occurred between variable degassed and crystallized magma portions during decompression. The geochemical and isotopic data of Procida glasses and rocks, and the compositional relationship between our MIs and those from slightly more evolved and radiogenic Phlegraean products, indicate that Procida basalts are an adequate parental end-member for the PVD. Our data suggest that a CO2- rich magma source was stored at depths of at least 13–14 km (i.e., 350 MPa) beneath the PVD. Fast ascent of magma batches directly started from this depth shortly before PVD trachy-basaltic to shoshonitic eruptions. Such results have implication on volcanic hazard assessment in the PVD area.923 113 - PublicationOpen AccessHydrothermal genesis and growth of the banded agates from the Allumiere-Tolfa volcanic district (Latium, Italy)In this work, we studied the hydrothermal agates from the Neogene–Quaternary volcanic district of Allumiere-Tolfa, northwest of Rome (Latium, Italy) using a combination of micro-textural, spectroscopic, and geochemical data. The examined sample consists of (1) an outer cristobalite layer deposited during the early stages of growth, (2) a sequence of chalcedonic bands (including i.e., length-fast, zebraic, and minor length-slow chalcedony) with variable moganite content (up to ca. 48 wt%), (3) an inner layer of terminated hyaline quartz crystals. The textures of the various SiO2 phases and their trace element content (Al, Li, B, Ti, Ga, Ge, As), as well as the presence of mineral inclusions (i.e., Fe-oxides and sulfates), is the result of physicochemical fuctuations of SiO2-bearing fuids. Positive correlation between Al and Li, low Al/Li ratio, and low Ti in hyaline quartz points to low-temperature hydrothermal environment. Local enrichment of B and As in chalcedony-rich layers are attributed to pH fuctuations. Analysis of the FT-IR spectra in the principal OH-stretching region (2750–3750 cm−1) shows that the silanol and molecular water signals are directly proportional. Strikingly, combined Raman and FT-IR spectroscopy on the chalcedonic bands reveals an anticorrelation between the moganite content and total water (SiOH+ molH2O) signal. The moganite content is compatible with magmatic-hydrothermal sulfate/alkaline fuids at a temperature of 100–200 °C, whereas the boron-rich chalcedony can be favored by neutral/acidic conditions. The fnal Bambauer quartz growth lamellae testifes diluted SiO 2-bearing solutions at lower temperature. These fndings suggest a genetic scenario dominated by pH fuctuations in the circulating hydrothermal fuid
45 8 - PublicationOpen AccessNaturally Occurring Asbestos (NOA) in Granitoid Rocks, A Case Study from Sardinia (Italy)(2018)
; ; ; ; ; ;; ;; All six minerals defined as “asbestos” by the existing regulation on asbestos hazard, i.e., actinolite, tremolite, anthophyllite, crocidolite and amosite amphiboles, and the serpentine-group mineral chrysotile are typical constituents of mafic and ultramafic magmatic rocks of ophiolitic sequences. However, little is known about the presence and distribution of naturally occurring asbestos (NOA) in plutonic felsic rocks. The Isadalu magmatic complex outcropping in central Sardinia and belonging to the post-variscan Permian volcanic cycle, is described here as an interesting occurrence of fibrous amphiboles in granitoid rocks. Field work and collected mineralogical/petrological data show that NOA fibers from the Isadalu complex belong compositionally to the actinolite-tremolite series. They were generated by metasomatic growth on pristine magmatic hornblende, at ca. 470 °C at 1 kbar, during sodic-calcic hydrothermal alteration. In terms of environmental hazard, the Isadalu complex represents a high-value case study, since the actinolite-bearing felsic rocks outcrop in a strongly anthropized area. Here, towns with local and regional strategic infrastructures (dams, pipes, hydroelectric power plants, water supply, roads) have been developed since the last century, also using the granitoid asbestos-rich stones. The aim of this study is to demonstrate that NOA and relative hazard are not univocally connected to a restricted typology of rocks. This result should be taken into account in any future work, procedure or regulation defining asbestos occurrences in natural environments69 119 - PublicationRestrictedApplication of micro-FTIR imaging in the Earth sciences(2010)
; ; ; ; ; ; ; ;Della Ventura, G.; Dipartimento Scienze Geologiche, Università Roma Tre, Roma, Italy ;Bellatreccia, F.; Dipartimento Scienze Geologiche, Università Roma Tre, Roma, Italy ;Marcelli, A.; INFN-Laboratori Nazionali di Frascati, Roma, Italy ;Cestelli Guidi, M.; INFN-Laboratori Nazionali di Frascati, Roma, Italy ;Piccinnini, M.; Porto Conte Ricerche S.r.l, Sassari, Italy ;Cavallo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piochi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; ; In this paper we describe recent applications of micro-infrared imaging in the Earth sciences. We address, in particular, the use of Fourier-transform infrared (FTIR) spectroscopy in characterizing the zoning and speciation of H and C in a variety of geological materials, including microporous minerals, nominally anhydrous volcanic minerals (NAMs), and crystal inclusions. These investigations show that use of the modern techniques of FTIR imaging enables detection of the zoning of volatile species across the studied samples, and possible configuration changes of structurally-bound carbon molecular species (e.g., CO2 vs CO3) during crystal growth. Such features, which are not accessible with other micro-analytical techniques, may provide information about the physicochemical properties which act as constraints in the genesis of the samples, and important information about the evolution of the geological system. Tests performed with focal-plane-array detectors (FPA) show that resolution close to the diffraction limit can be achieved if the amounts of the target molecules in the sample are substantially different. We also point out the possibility of using FTIR imaging for investigations under non-ambient conditions.291 23 - PublicationRestrictedSynthesis and solid solution in “rubidium richterite”, Rb(NaCa)Mg5 Si8 O22 (OH,F)2The OH–F substitution in “synthetic Rb-richterite” has been investigated along the join Rb(NaCa)Mg5Si8O22(OH)2–Rb(NaCa) Mg5Si8O22(F)2. Syntheses were done by conventional hydrothermal techniques (Tuttle-type vessels) at 800 °C, 1 kbar P( H2O). SEM microscopy showed very high yields of acicular to prismatic amphibole crystals up to XF = F/(F + OH) = 0.6. Beyond this value, a micaceous phase and a very fine-grained granular phase were present. Powder X-ray diffraction patterns show a single amphibole phase below XF = 0.6; above XF = 0.6, a distinct peak at d = 12.18 Å indicates the presence of a mica and there is a broad hump starting at ~ 20o 2θ and ~ 15o wide, both features increasing in intensity with increasing XF. Cell dimensions at XF = 0 are compatible with an ideal amphibole composition Rb(NaCa)Mg5Si8O22(OH)2 and evolve with increasing XF up to XF = 0.6, where there is a sharp discontinuity in a, β and V. The infrared OH-stretching spectrum of the OH end-member shows a main band at 3732 cm−1 which is assigned to the local MgMgMg–OH→ Rb arrangement, and a minor band at 3670 cm−1 assigned to the local MgMgMg–OH→ □ arrangement. This latter band indicates a slight departure toward tremolite. Intermediate OH–F compositions show the appearance of a second band at 3718 cm−1, whose intensity is proportional to the F content in the system, in accord with OH−OH and OH–F arrangements across the filled A-site. For XF > 0.6, the OH-stretching spectra are complicated by the appearance of two more peaks at 3705 and 3685 cm−1. Additional bands at lower wavenumbers, centered around 3595, 3540 and 3475 cm−1, respectively, are better resolved by collecting the spectra on disks heated at 250 °C to remove the adsorbed moisture in the pellet. Combining the behavior of unit-cell dimensions and the infrared spectra with mass-balance arguments indicates that at high XF values, Na replaces part of the Rb at the A-site in the amphibole and the tremolite component of the amphibole increases, while “Rb tetrasilicic magnesium mica” crystallizes, along with semi-amorphous nanophases. The variation in band intensities as a function of XF indicates that OH and F randomly occupy local pairs of O(3) sites across a (filled) A-site, and that there is no short-range order of OH and F.
35 2 - PublicationOpen AccessNanoscale transformations of amphiboles within human alveolar epithelial cells(2022-02-02)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ;Amphibole asbestos is related to lung fibrosis and several types of lung tumors. The disease-triggering mechanisms still challenge our diagnostic capabilities and are still far from being fully understood. The literature focuses primarily on the role and formation of asbestos bodies in lung tissues, but there is a distinct lack of studies on amphibole particles that have been internalized by alveolar epithelial cells (AECs). These internalized particles may directly interact with the cell nucleus and the organelles, exerting a synergistic action with asbestos bodies (AB) from a different location. Here we document the near-atomic- to nano-scale transformations induced by, and taking place within, AECs of three distinct amphiboles (anthophyllite, grunerite, "amosite") with different Fe-content and morphologic features. We show that: (i) an Fe-rich layer is formed on the internalized particles, (ii) particle grain boundaries are transformed abiotically by the internal chemical environment of AECs and/or by a biologically induced mineralization mechanism, (iii) the Fe-rich material produced on the particle surface does not contain large amounts of P, in stark contrast to extracellular ABs, and (iv) the iron in the Fe-rich layer is derived from the particle itself. Internalized particles and ABs follow two distinct formation mechanisms reaching different physicochemical end-states.20 4 - PublicationRestrictedSynthetic ANaB(NaxLi1 ¡ xMg1)CMg5Si8O22(OH)2 (with x = 0.6, 0.2 and 0) P21/m amphiboles at high pressure: a synchrotron infrared study(2009)
; ; ; ;Iezzi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Liu, Z. ;Della Ventura, G.; ;high-pressure behavior of three synthetic amphiboles crystallized with space group P21/m at room conditions in the system Li2O–Na2O–MgO–SiO2–H2O has been studied by in situ synchrotron infrared absorption spectroscopy. The amphiboles have compositions ANa B(NaxLi1 ¡ xMg1) CMg5 Si8 O22(OH)2 with x = 0.6, 0.2 and 0.0, respectively. The high-P experiments up to 32 GPa were carried out on the U2A beamline at Brookhaven National Laboratory (NY, USA) using a diamond anvil cell under non-hydrostatic or quasi-hydrostatic conditions. The two most intense absorption bands in the OH-stretching infrared spectra can be assigned to two non-equivalent O–H dipoles in the P21/m structure, bonded to the same local environment M1M3Mg3–OH–ANa, and pointing toward two diVerently kinked tetrahedral rings. In all samples these bands progressively merge to give a unique symmetrical absorption with increasing pressure, suggesting a change in symmetry from P21/m to C2/m. The pressure at which the transition occurs appears to be linearly correlated to the aggregate B-site dimension. The infrared spectra collected for amphibole B(Na0.2Li0.8Mg1) in the frequency range 50 to 1,400 cm¡1 also show a series of changes with increasing pressure. The data reported here support the inference of Iezzi et al. (Am Miner 91:479–482, 2006a) regarding a new high-pressure C2/m amphibole polymorph characterized by two equivalent and kinked double-chains, stable at very high-pressure.140 21