Fabio Bellatreccia

Characterization of amphibole fibres linked to mesothelioma in the area of Biancavilla, Eastern Sicily, Italy

Abstract An epidemiological and environmental study of the area around Biancavilla (CT, Italy) was prompted by a significant incidence of malignant pleural mesothelioma, which was not related to a specific occupational activity. An environmental dispersion of fibres was found and attributed to local quarry activities, whose extracted volcanic products also contained fibrous amphiboles and had been used extensively in the local building industry, especially in the period 1960-1970. Abundant yellowish and grey-whitish asbestiform amphiboles with strongly asymmetric morphology were identified in this study, intimately associated with albitic feldspar, hematite and very minor orthopyroxene. These minerals fill the pores of the altered volcanic host rock (metasomatized benmoreitic lavas and pyroclastic rocks). The Rietveld method allowed a quantitative mineralogical analysis of the mineral mixture (24% amphiboles-asbestos, 73% feldspar and 3% hematite). The crystal size and morphology of the grey-whitish amphibole fibres do not allow quantitative microprobe analyses; semi-quantitative EDS-SEM analyses of a prismatic mineral known to be fluoroedenite and the unknown fibrous crystals studied here suggest that they are the same mineral, although the fibres are generally depleted in Ca and Mg. The F content is the same in both occurrences. Unitcell parameters of the fibres are: a = 9.815(1), b = 17.992(3), c = 5.2733(6) Å , β = 104.547(9)º, V = 901.4(3) Å3, and the refractive indices are in the range 1.60 -1.63. Optical, chemical and Rietveld analyses of the fibres confirm their similarity with the yellow prismatic fluoro-edenite previously analysed. Biancavilla is the first occurrence of amphibole fibres in a volcanic context (the Etnean volcanic complex). These fibres have a very anomalous composition (high ANa, IVAl and O3F contents) in comparison to other known oncogenic minerals.

Single-crystal FTIR and X-ray study of vishnevite, ideally [Na6(SO4)][Na2(H2O)2](Si6Al6O24)

Abstract This paper reports a single-crystal FTIR spectroscopic study of vishnevite, ideally [Na6(SO4)] [Na2(H2O)2](Si6Al6O24), a member of the cancrinite group of feldspathoids. The study was done on several crystals from various geological occurrences. Infrared spectra show that most samples, and in particular the specimens from the holotype locality at Vishnevye Mountains (Urals, Russia), contain molecular CO2 as the main carbon species in the structural pores, while the specimens from Loch Borolan (Scotland) were found to be CO3-rich. Polarized-light measurements show that the linear CO2 molecules are oriented perpendicular to the crystallographic c axis. Structure refinement of sample Pi4 from Latium (Italy) shows usual H2O···Na···H2O sequences within the undecahedral cages; however, difference Fourier maps suggest the presence of additional protons in the channels, possibly forming OH groups. The FTIR spectra show three absorptions in the 3800.3200 cm-1 region. The first one, at 3590 cm-1 is strongly polarized for E||c while the second, at 3535 cm-1, behaves almost isotropic. These two bands are assigned to the stretching vibrations of an asymmetric water molecule in the structural cages. The third broad absorption at 3320 cm-1, is predominantly polarized for E||c and is assigned to additional OH groups in the channels. Detailed microspectroscopic mapping showed several samples from Latium (Italy) to be zoned with respect to the CO2/CO3 content, thus pointing to a possible use of the volatile content of these minerals for petrological modeling.

Ti-rich phlogopite from Mt. Vulture (Potenza, Italy) investigated by a multianalytical approach : substitutional mechanisms and orientation of the OH dipoles

Trioctahedral mica samples, collected at Cava St. Antonio (Mt. Vulture, Italy) were studied by combining electron-microprobe and C-H-N elemental analyses, single-crystal X-ray diffraction refinement, Mossbauer and Fourier transform infrared spectroscopies. Electron-microprobe analyses show the crystals to be quite homogeneous with TiO 2 ∼3 wt% and F ranging from 0.42 to 0.59 wt%. Quantitative analyses of H combined with ferric/ferrous ratios from Mossbauer data allowed reliable crystal-chemical formulae to be derived. The results suggest that the entry of both Ti 4+ and Fe 3+ in the structure occurs through R-oxy substitution mechanisms involving deprotonation at O(4). This inference is supported by X-ray structure-refinement results (notably the c cell-parameter, the off-centering of the M2 cation towards O(4), the bond-length distortions of the cis -M2 octahedron) obtained using anisotropic thermal parameters in space group C2/ m . The amount of oxy-substitutions from both electron-microprobe and X-ray data is in agreement with carbon-hydrogen-nitrogen analyses which give an average anion composition (OH 1.25 O 0.65 F 0.10 ). Polarized-light infrared spectroscopy shows a complex OH-stretching spectrum which is composed of several overlapping (at least five) components. These can be assigned to the main octahedral local configurations that are compatible with the chemical composition. Pleochroic Fourier transform infrared spectroscopy measurements done along the principal optical directions show that the O-H bond axis is tilted from [001] and provide the average orientation of the O-H dipole in the structure: O-H ⁁ α ∼ 23° and O-H ⁁ γ ∼ 56°.

Monazite-huttonite solid-solutions from the Vico Volcanic Complex, Latium, Italy

Abstract The crystal-chemical relationships occurring within a single grain of monazite-(Ce) from Vetralla, Vico Volcanic Complex, north of Rome, are outlined. The sample is from a miarolitic cavity in a holocrystalline ejectum consisting of K-feldspar plus minor plagioclase, mica and Fe-oxides, collected from a pyroclastic explosive level. The Gandolfi film (Cu-Kα radiation) can be indexed in space group P21 /n with a = 6.816(4); b = 6.976(4); c = 6.471(3) Å ,β = 103.63(3)° :V = 299.0(6) Å3. Electron-probe microanalyses plot within the field of monazite along the huttonite-monazite edge of the huttonite-monazite-brabantite triangle. Despite patchy and irregular zoning, the grain shows a clear enrichment towards pure monazite at the outer rim. A constant Th:Si ratio of 1:1 indicates the existence of a simple solid-solution between huttonite and monazite. The substitution can be written as Th4+ + Si4+ → REE3+ + P5+ without requiring any electrostatic compensation by divalent cations, or by anionic groups. The REE distribution pattern is compatible with that of monazites from syenitic rocks.

On the crystal structure and crystal chemistry of pollucite, (Cs,Na)16Al16Si32O96·nH2O: A natural microporous material of interest in nuclear technology

Abstract The crystal structure and crystal chemistry of two natural pollucite samples, from Buckfield, Oxford County, Maine (sample M3), and from Kanzit Mawaie, Laghman, Nooristan, Afghanistan (sample N5), have been investigated by means of wavelength-dispersive X-ray microanalysis, thermogravimetric analysis, single-crystal X-ray and neutron diffraction, and single-crystal Fourier-transform infrared spectroscopy. The X-ray and neutron diffraction patterns of the two pollucite crystals show a metrically cubic unit cell [with aM3 = 13.6914(6) Å and aN5 = 13.6808(6) Å by neutron diffraction data; the deviation from isometry is <1.5σ(li), where li is the unrestrained unit-cell length] and the reflection conditions are consistent with the space group Ia3d. Anisotropic neutron structural refinements gave final agreement indices: R1 = 0.0543 for 32 refined parameters and 372 unique reflections with Fo > 4σ(Fo) for M3 and R1 = 0.0693 for 31 refined parameters and 331 unique reflections with Fo > 4σ(Fo) for N5. The structure refinements show a disordered Si/Al-distribution in the tetrahedral framework. The analysis of the difference-Fourier maps of the nuclear density confirms the presence of extraframework water molecules with oxygen sharing the Cs site (at 1/8, 1/8, 1/8, Wyckoff-16b position). However, the minima, ascribable to the proton sites, are very weak in density. Two possible proton positions, leading to a reasonable H2O configuration, are given, and the possible hydrogen bonding is described. Sodium is located at 1/4, 1/8, 0 (Wyckoff-24c position). The main IR absorption bands in the regions typical of H2O are assigned, and the presence of hydroxyls in the studied samples is ruled out. Neutron diffraction and FTIR data agree with the presence of very weak hydrogen bonds in the structure. The detailed description of the crystal structure and crystal chemistry of pollucite (e.g., Si/Al-distribution, configuration of the extra-framework content, possible hydrogen bonding scheme) reported in this study is the key to understand the high thermo-elastic stability of pollucite, the immobility of Cs at non-ambient conditions, and the extremely low leaching rate of Cs, which make this open-framework silicate a promising material with potential use for fixation and deposition of Cs radioisotopes

CO2 in minerals of the cancrinite-sodalite group: pitiglianoite

This paper presents spectroscopic evidence for the presence of CO 2 molecules within the structural channels of a member of the cancrinite-sodalite group of feldspathoids. The study was carried out using single-crystal micro-FTIR spectroscopy on a sample of pitiglianoite from Monte Cavalluccio (Bonaccorsi & Orlandi, 1996). A sharp and prominent band is observed in the medium-infrared range at 2351 cm -1 , which can be assigned to carbon dioxide molecules in the studied sample. Polarized-light FTIR spectra collected on a 112-μm-thick [001] section show maximum absorption with E ⊥ c , suggesting that the linear CO 2 molecules are oriented perpendicular to the crystallographic c axis, as in beryl (Wood & Nassau, 1967) or cordierite (Armbruster & Bloss, 1980). In situ high- T FTIR data collection up to 550°C shows that the CO 2 band decreases in intensity and broadens with increasing T ; release of carbon dioxide from the structure starts at T > 250°C and is complete at ∼ 450°C. The same kind of behaviour is observed for structural H 2 O; upon heating pitiglianoite becomes virtually anhydrous at T ∼ 500°C. These data suggest that the extraframework volatile composition of cancrinite-type minerals is strongly T dependent, hence the analysis of pitiglianoite may provide geothermometric information on the genetic environment (typically late-stage volcanic) of these minerals.

FTIR imaging in diffusion studies: CO2 and H2O in a synthetic sector-zoned beryl

In this work we investigate the strongly inhomogeneous distribution of CO2 and H2O in a synthetic beryl having a peculiar hourglass zoning of Cr due to the crystal growth. The sample was treated at 800°C, 500 MPa, in a CO2-rich atmosphere. High-resolution FESEM images revealed that the hourglass boundary is not correlated to physical discontinuities, at least at the scale of tens of nanometers. Polarized FPA-FTIR imaging, on the other side, revealed that the chemical zoning acts as a fast pathway for carbon dioxide diffusion, a feature never observed so far in minerals. The hourglass zone boundary may be thus considered as a structural defect possibly due to the mismatch induced by the different growth rates of each sector. High-resolution synchrotron-light FTIR imaging, in addition, also allows enhancement of CO2 diffusion along the hourglass boundary to be distinguished from diffusion along fractures in the grain. Therefore, FTIR imaging provides evidence that different diffusion mechanisms may locally combine, suggesting that the distribution of the target molecules needs to be be carefully characterized in experimental studies. This piece of information is mandatory when the study is aimed at extracting diffusion coefficients from analytical profiles. Combination of TOF-SIMS and FPA data shows a significant depletion of type II H2O along the hourglass boundary, indicating that water diffusion could be controlled by the distribution of alkali cations within channels, coupled to a plug effect of CO2.

Fantappièite, a new mineral of the cancrinite-sodalite group with a 33-layer stacking sequence: Occurrence and crystal structure

Abstract This paper reports the occurrence and the crystal structure of fantappièite, a new member of the cancrinite-sodalite group of minerals from Torre Stracciacappe, Trevignano community (Rome, Latium, Italy). The mineral occurs within a volcanic ejectum consisting of dominant sanidine with minor plagioclase, biotite, augitic clinopyroxene, andradite, and iron oxides. Fantappièite (0.7 mm as largest size) is observed within miarolitic cavities of the rock as transparent colorless crystals, showing complex morphologies and striated faces. It is non-pleochroic and uniaxial negative, nω = 1.5046(5) and nε = 1.5027(5). Dcalc is 2.471 g/cm3. Fantappièite is trigonal, space group P3̄; the cell parameters are: a = 12.8742(6), c = 87.215(3) Å, V = 12518.8(9) Å3, Z = 1. The empirical chemical formula is: (Na84.12Ca30.00K15.95Fe0.19Ti0.13Mn0.10Mg0.09)(Si99.36Al98.64)O396(SO4)30.24(CO3)0.29Cl0.84F0.82∙5.18H2O, which corresponds to the ideal formula [Na82.5Ca33K16.5]Σ=132(Si99Al99O396)(SO4)33·6H2O. The five strongest reflections in the X-ray powder pattern are [d in Å (I %) (hkl)]: 3.70 (100) (3 0 0), 3.60 (80) (1 0 23), 2.641 (65) (0 0 33), 6.85 (60) (0 1 10), 6.40 (55) (1 1 0). The single-crystal FTIR spectrum rules out OH groups and shows the presence of H2O and CO2 molecules, as well. The structure can be described as a stacking sequence of 33 layers of six-membered rings of tetrahedra along the c axis. The stacking sequence is ACBACABACBACBACBCACBACBACBABCBACB…, where A, B, and C represent the positions of the rings within the layers. This sequence gives rise to liottite, sodalite, and cancrinite cages, alternating along c. Sulfate groups occur within the liottite cages associated by Na, K, and Ca, while highly disordered sulfate groups are located within the sodalite cages. H2O groups occur within the cancrinite cages, bonded to Ca and Na cations. Split positions are found for Na-Ca sites, and are related to disordering of the sulfate groups in the sodalite cages.

Farneseite, a new mineral of the cancrinite - sodalite group with a 14-layer stacking sequence occurrence and crystal structure

ab S tra C t This paper reports the occurrence and the crystal structure of fantappieite, a new member of the cancrinite-sodalite group of minerals from Torre Stracciacappe, Trevignano community (Rome, Latium, Italy). The mineral occurs within a volcanic ejectum consisting of dominant sanidine with minor plagioclase, biotite, augitic clinopyroxene, andradite, and iron oxides. Fantappieite (0.7 mm as largest size) is observed within miarolitic cavities of the rock as transparent colorless crystals, showing complex morphologies and striated faces. It is non-pleochroic and uniaxial negative, nω = 1.5046(5) and ne = 1.5027(5). Dcalc is 2.471 g/cm 3 . Fantappieite is trigonal, space group P3; the cell parameters are: a = 12.8742(6), c = 87.215(3) A, V = 12518.8(9) A 3 , Z = 1. The empirical chemical formula is: (Na84.12Ca30.00K15.95Fe0.19Ti0.13Mn0.10Mg0.09)(Si99.36Al98.64)O396(SO4)30.24(CO3)0.29Cl0.84F0.82∙5.18H2O, which corresponds to the ideal formula [Na82.5Ca33K16.5]Σ=132(Si99Al99O396)(SO4)33·6H2O. The five strongest reflections in the X-ray powder pattern are [d in A (I %) (hkl)]: 3.70 (100) (3 0 0), 3.60 (80) (1 0 23), 2.641 (65) (0 0 33), 6.85 (60) (0 1 10), 6.40 (55) (1 1 0). The single-crystal FTIR spectrum rules out OH groups and shows the presence of H 2O and CO2 molecules, as well. The structure can be described as a stacking sequence of 33 layers of six-membered rings of tetrahedra along the c axis. The stacking sequence is ACBACABACBACBACBCACBACBACBABCBACB…, where A, B, and C represent the positions of the rings within the layers. This sequence gives rise to liottite, sodalite, and cancrinite cages, alternating along c. Sulfate groups occur within the liottite cages associated by Na, K, and Ca, while highly disordered sulfate groups are located within the sodalite cages. H 2O groups occur within the cancrinite cages, bonded to Ca and Na cations. Split positions are found for Na-Ca sites, and are related to disordering of the sulfate groups in the sodalite cages.

Non-metamict zirconolite polytypes from the feldspathoid-bearing alkali-syenitic ejecta of the Vico volcanic complex (Latium, Italy)

This paper presents the results of a combined electron microprobe and analytical TEM study that describes the chemical and structural characteristics of non-metamict zirconolite from a volcanic ejectum collected within a pyroclastic formation of the Vico volcanic complex, near Tre Croci Community, Latium (Italy). The host rock is a foid-bearing alkali-syenite and consists of potassium-feldspar and plagioclase, with minor biotite, titanite, clinopyroxene and magnetite. Sodalite occurs as well-faceted crystals inside miarolitic cavities between intersecting feldspars and it is variably altered to a kaolinite-like product. Accessory minerals include zircon, baddeleyite, stillwellite, hellandite, fluorite, apatite and monazite. Zirconolite occurs both as elongated acicular crystals of orthorhombic symmetry (zirconolite-3 O ), space group Acam, with (in A) a = 10.13(1), b = 14.16(1) and c = 7.288(2), and as pseudo-hexagonal platy crystals of trigonal symmetry (zirconolite-3 T ), space group P 3 1 2, with a = 7.279(2) and c = 16.89(2). TEM studies revealed additionally the presence of polytype zirconolite-2 M in a subset of grains analyzed. Zirconolite displays pronounced compositional zoning, observed in backscattered electron images, resulting mainly from an antipathetic variation in the actinide elements (Th + U) and REE contents. Analytical TEM results indicate compositional differences exist between the zirconolite-3 T and zirconolite-2 M polytypes. Zirconolite, and associated accessory REE, Th, U minerals crystallized after the formation of the major rock-forming minerals of the ejectum, from metasomatic fluids rich in F and P.