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The very rapid energy release from impact events, such as those resulting from lightning strikes or meteorites, can drive a variety of physical and chemical processes which alter rocks and result in the formation of natural glasses (i.e., fulgurites and tektites). Fulgurite is the vitrified soil, sand, or rock resulting from lightning strikes. A thunderbolt is associated with air temperatures of up to 105 K, which can heat rocks to >2000 K within tens of microseconds. The rapid fusing and subsequent quenching of the surface of the rock leaves a distinctive, thin, garbled coating composed of a glassy to fine-grained porous material. Previous studies on rock fulgurites found planar deformation features in quartz crystals within the target rock substrate, evidence of strong shock waves during fulgurite formation. In this paper, we simulated the shock pressure and temperature caused by an idealized lightning impact on rocks and compared the model results with observations on rock fulgurites from the literature. Our model results indicate that a lightning strike can cause >7 GPa pressure on the rock surface, generate a layer of fulgurite (of radius ∼9 cm), and leave a burned region (of radius ∼11 cm). The fulgurites found on rock surfaces share many features with sand fulgurites, but their spatial distribution is completely different, as sand fulgurites are hollow tube structures. Our study on rock fulgurites provides an indirect constraint on the energy of a lightning event and also demonstrates that the presence of shock features in rocks cannot be taken as unequivocal evidence for impact events.

Tungsten-rich oxycalciobetafite occurs in complex Ti-rich hydrothermal veins emplaced within dolomite marble in the contact aureole of the Adamello batholith, northern Italy, where it occurs as overgrowths on zirconolite. The betafite is weakly zoned and contains 29–34 wt% UO2. In terms of end-members, the betafite contains approximately 50 mol% CaUTi2O7 and is one of the closest known natural compositions to the pyrochlore phase proposed for use in titanate nuclear waste forms. Amorphization and volume expansion of the betafite caused cracks to form in the enclosing silicate mineral grains. Backscattered electron images reveal that betafite was subsequently altered along crystal rims, particularly near the cracks. Electron probe microanalyses reveal little difference in composition between altered and unaltered areas, except for lower totals, suggesting that alteration is primarily due to hydration. Zirconolite contains up to 18 wt% ThO2 and 24 wt% UO2, and exhibits strong compositional zoning, but no internal cracking due to differential (and anisotropic) volume expansion and no visible alteration. The available evidence demonstrates that both oxycalciobetafite and zirconolite retained actinides for approximately 40 million years after the final stage of vein formation. During this time, oxycalciobetafite and zirconolite accumulated a total alpha-decay dose of 3.0–3.6 × 1016 and 0.2–2.0 × 1016 α/mg, respectively.

Fulgurites are a naturally occurring glass formed when sand, rock, or soil is struck by atmospheric electrical discharges (lightning). The aim of this paper is to provide insights into the conditions occurring in rocks during the lightning strike. Rock fulgurites collected from Mt. Mottarone, Baveno (Piedmont, Italy) have been investigated to assess the mineralogical and compositional changes occurring in granite due to a lightning strike. X-ray powder diffraction showed that the samples represent the dominant granitic rock type of the Baveno massif, the so-called “Pink Baveno.” Fulgurite coats the surface of the granite as a brown-black, glassy to very fine-grained porous layer. Powder diffraction data for the fulgurite reveal the presence of cristobalite and quartz crystals in a glass matrix, suggesting that temperature exceeded ~1700 °C at near atmospheric conditions, assuming thermodynamic equilibrium. Electron probe microanalysis of the glass revealed that it is mainly composed of SiO 2 and Al 2 O 3 and that it has a porosity of 5–7 area% in the studied zones. The presence of the amorphous phase indicates that the abrupt electrical (Joule) heating of the rock surface yielded high temperatures, producing a thin melt layer on the surface, which then cooled adiabatically. Idealized physical model was developed to simulate the effects of Joule heating and subsequent thermal conduction close to the rock surface during and after a lightning strike. The quantity of organic matter in the glass, obtained via Elemental Analyzer, suggests that rapid quenching of the melt trapped NO x and CO x gases produced during heating. Raman spectroscopy revealed the presence of polyaromatic hydrocarbon molecules, which, combined with the Elemental Analyzer data, suggest that organic matter was pyrolyzed at around 300–350 °C and then trapped in the glass matrix of the studied rock fulgurites.

In nature, asbestos is often associated with minerals and other non-asbestiform morphologies thought to be harmless, but not much is known about the potential toxic effects of these phases. Therefore, the characterization of natural assemblages should not be limited to asbestos fibers only. This paper combines a multi-analytical characterization of asbestos from Valmalenco (Italy) with data from dissolution experiments conducted in a simulated interstitial lung fluid (Gamble&rsquo, s solution), and a detailed dimensional study that compares the particle population before and after this interaction. The sample is identified as a tremolitic amphibole, exhibiting a predominance of fiber and prismatic habits at lower magnification, but a bladed habit at higher magnification. The results show that at different magnification, the dimensional and habit distributions are notably different. After the dissolution experiments, the sample showed rounded edges and pyramid-shaped dissolution pits. Chemical analyses suggested that a nearly stoichiometric logarithmic loss of Si and Mg occurred associated with a relatively intense release of Ca in the first 24 h, whereas Fe was probably redeposited on the fiber surfaces. A rearrangement of the more frequent habits and dimensions was recorded after the dissolution experiment, with a peculiar increase of the proportion of elongated mineral particles.

This study examines the influence of different analysis techniques on the results concerning the particle size distribution and mineralogical composition of airborne particles. Volcanic ash from the Eyjafjalla volcano was examined with a transmitted light microscope (TLM), a scanning electron microscope (SEM), SEM equipped with an automatic single-particle analysis program, and an electron microprobe (EMP) and the results differ considerably. Main error source is the specific particle size determination for each method. Here, a sample containing airborne particles of volcanic material was analyzed for size-differentiated particle number (n) on the evaluation area per unit time (number settling rate). The results of the TLM reveal a higher abundance of particles ≥8 μm than those obtained by manual SEM and EMP analysis, whereas the opposite is observed for particles

Passive samplers for collection of coarse airborne particulate matter have been installed in and around the coal-mining town of Cam Pha, Quang Ninh Province (Vietnam). Analysis of Pb, Sr, and Nd isotope ratios and of major and trace element distribution patterns in atmospheric particulates collected at three stations allowed for the identification of four important dust components: (1) coal dust from an open-pit mine and fly ash particles from a coal-fired power station, (2) diesel soot, (3) traffic dust from metal, tire and pavement abrasion, and (4) limestone-derived dust. Outside of the coal-mining area, traffic-derived dust defines the atmospheric baseline composition of the studied environment.

This study presents a detailed mineralogical and chemical characterization of a chromium contamination in alluvial deposits underlying a leather tannery in Austria. Drill cores revealed that the contamination is represented by a black layer that exhibits sharp boundaries with adjacent brown alluvial sediments. This black layer is located below the groundwater table and begins at the source of the contamination. The black layer thickens with increasing distance from the source and the depth of the upper boundary remains at the same level relative to the surface. Mineralogical and chemical investigations showed that the black layer contains reduced Cr phases, a Cr(III) hydroxide and a Cr(III)-Ca-containing hydrocalcite, which are present as discrete grains, in vein-like pore spaces and/or as a coating around mineral grains. Cr(VI) is nearly only present above the groundwater table. Our 2-D model predicts a longitudinal spread of the black layer of approximately 37 m downgradient from the source and a maximum transversal spread of approximately 10 m. This study shows that, if the source of the contamination is not eliminated, the plume will increase continuously farther downgradient.

Book Review: Amazonite: Mineralogy, Crystal Chemistry, and Typomorphism. (2016) By Mikhail Ostrooumov. Elsevier. ISBN: 978-0-1280-3721-8, 228 p. $120. This new book is a translation of the original Russian language edition, which the author Mikhail Ostrooumov published in 2008 together with his colleagues A. Platonov and V. Popov (Ostrooumov et al. 2008). The Russian version was based on a precursor volume, which became a bibliographic rarity shortly after its publication in 1989 (Vochmentzev et al. 1989). The 2008 version, and the English translation reviewed here, expand upon the 1989 edition of the monograph by including subsequent research results, making corrections, and by adding more recent references. The book is dedicated to amazonite, a variety of potassium feldspar that, due to its distinct colors, has intrigued humans since antiquity, as has been noted by the renowned mineralogist Alexander Fersman. The recent discovery of Neolithic, and possibly even older, amazonite beads in archeological sites in Israel (Bar-Yosef Mayer and Porat 2008) highlights the fascination with this green, greenish-blue, or blue mineral. At that time (10 500–8200 B.P.), i.e., during the transition from hunting and gathering to agriculture in the Near East, the earliest farmers had to make great efforts at obtaining the raw materials from far-away places. It is clear why this variety of potassium feldspar presents …

To investigate the potential of substituting non-natural agents in sunscreen, mixtures of some clays with Ganoderma pfeifferi extract were examined in regard to their protection abilities against ultraviolet (UV) radiation in the wavelength range 250–400 nm. Some mixtures showed remarkably high UV-protection potential in comparison with corresponding clay cream devoid of the fungal extract. Depending on interlayer charge of the dominant clay mineral contained in the clays, the interaction between the fungal extract and the clay mineral played a key role in the UV-protection ability of the mixtures. The optimal clay in the mixture with the G. pfeifferi extract for sunscreens was dominated by expandable clay minerals with low interlayer charge.

A new scheme of nomenclature for the pyrochlore supergroup, approved by the CNMNC-IMA, is based on the ions at the A, B and Y sites. What has been referred to until now as the pyrochlore group should be referred to as the pyrochlore supergroup, and the subgroups should be changed to groups. Five groups are recommended, based on the atomic proportions of the B atoms Nb, Ta, Sb, Ti, and W. The recommended groups are pyrochlore, microlite, rom£ite, betafite, and elsmoreite, respectively. The new names are composed of two prefixes and one root name (identical to the name of the group). The first prefix refers to the dominant anion (or cation) of the dominant valence [or HO or □] at the Y site. The second prefix refers to the dominant cation of the dominant valence [or HO or □] at the A site. The prefix "keno-" represents "vacancy". Where the first and second prefixes are equal, then only one prefix is applied. Complete descriptions are missing for the majority of the pyrochlore-supergroup species. Only seven names refer to valid species on the grounds of their complete descriptions: oxycalciopyrochlore, hydropyrochlore, hydroxykenomicrolite, oxystannomicrolite, oxystibiomicrolite, hydroxycalciorom6ite, and hydrokenoelsmoreite. Fluornatromicrolite is an IMA-approved mineral, but the complete description has not yet been published. The following 20 names refer to minerals that need to be completely described in order to be approved as valid species: hydroxycalciopyrochlore, fiuornatropyrochlore, fluorcalciopyrochlore, fluorstrontiopyrochlore, fluorkenopyrochlore, oxynatropyrochlore, oxyplumbopyrochlore, oxyyttropyrochlore-(Y), kenoplumbopyrochlore, fluorcalciomicrolite, oxycalciomicrolite, kenoplumbomicrolite, hydromicrolite, hydrokenomicrolite, oxycalciobetafite, oxyuranobetafite, fluornatroromite, fluorcalcioromeite, oxycalcioromdite, and oxyplumborom£ite. For these, there are only chemical or crystal-structure data. Type specimens need to be defined. Potential candidates for several other species exist, but are not sufficiently well characterized to grant them any official status. Ancient chemical data refer to wet-chemical analyses and commonly represent a mixture of minerals. These data were not used here. All data used represent results of electron-microprobe analyses or were obtained by crystal-structure refinement. We also verified the scarcity of crystal-chemical data in the literature. There are crystal-structure determinations published for only nine pyrochlore-supergroup minerals: hydropyrochlore, hydroxykenomicrolite, hydroxycalcioromite, hydrokenoelsmoreite, hydroxycalciopyrochlore, fluorcalciopyrochlore, kenoplumbomicrolite, oxycalciobetafite, and fluornatrorom£ite. The following mineral names are now discarded: alumotungstite, bariomicrolite, bariopyrochlore, bindheimite, bismutomicrolite, bismutopyrochlore, bismutostibiconite, calciobetafite, ceriopyrochlore-(Ce), cesstibtantite, ferritungstite, jixianite, kalipyrochlore, monimolite, natrobistantite, partzite, plumbobetafite, plumbomicrolite, plumbopyrochlore, stannomicrolite, stetefeldtite, stibiconite, stibiobetafite, stibiomicrolite, strontiopyrochlore, uranmicrolite, uranpyrochlore, yttrobetafite-(Y), and yttropyrochlore-(Y).

The potential of various clays including kaolin, smectite, mixed-layer series-dominated clay and mica-dominated clay to protect against ultraviolet (UV) radiation in the range 250–400 nm was examined. In order to understand the UV-protection abilities of the clays, properties of the clays were also characterized. The clays blocked UV radiation and bulk Fe2O3 content played a key role in the UV-protection properties, whereby the higher the bulk Fe2O3 content, the lower the UV-transmission level. However, UV-protection ability also depended on the expandability of the clay or the combination between clay mineral and mixed ointment.

A granitic pegmatite associated with the Monte Bruffione granodiorite in the Tertiary Adamello Massif, Italy, consists primarily of albite, potassium feldspar, muscovite, quartz, and spessartine (graphic intergrowths with quartz). As accessory minerals, the pegmatite contains magnetite, pyrophanite, monazite-(Ce), uraninite, xenotime-(Y), zircon, and fergusonite-(Y). This yttrium niobate mineral contains inclusions of Th-rich uraninite, and is itself rich in UO 2 (average 7.1 ± 1.1 wt.%, n = 34) and ThO 2 (average 3.5 ± 1.0 wt.%). Many fergusonite crystals display growth zoning, characterized by a general increase towards the rim in the contents of Y and rare earth elements at the expense of U and Th. Irregular or patchy zoning as well as sector zoning are also observed in some of the crystals. Due to the alpha-decay of the U and Th fergusonite is metamict, as documented by transmission electron microscopy (TEM) and micro-Raman spectroscopy. Nevertheless, the mineral could be identified as fergusonite-(Y) on the basis of a canonical discriminant analysis of its chemical composition and on the basis of the close similarity of its Raman spectrum with that of a reference β -fergusonite. The crystalline-to-metamict transformation was associated with macroscopic swelling, as indicated by microfractures that are arranged radially around fergusonite inclusions in pyrophanite. The TEM data revealed that the amorphous fergusonite contains U-rich nanocrystals (5–15 nm across), which in most cases are distributed randomly and which probably nucleated after metamictization. The TEM investigations further revealed the ubiquitous presence of nano-sized (typically 5–25 nm across), nearly circular features, which exhibit a low diffraction contrast and which we interpret as nanopores. We propose that these nanopores represent former bubbles of radiogenic helium. The data presented here allowed us to determine that the critical amorphization dose of fergusonite is ≤ 0.97 × 10 16 alphas/mg, i.e., lower than that of other actinide-rich oxide minerals (e.g., pyrochlore). The presence of the U-rich nanocrystals indicates that fergusonite is able to retain actinides even when it is entirely metamict and even if it is surrounded by microfractures, which represent potential fluid pathways. This result suggests that fergusonite could be a phase suitable to be included in ceramics designed for the immobilization of high-level nuclear waste.

Medium-sulfur bituminous coal and a mixture of 95 wt.% coal plus 5 wt.% tire-derived fuel (TDF) in the form of shredded automotive tires were combusted in a stoker boiler under the same conditions. This paper presents quantitative chemical compositions of the fuels and of the gaseous and particulate emissions. The coal + TDF mixture is considerably richer in Zn than the pure coal as a result of the high Zn content of the shredded tires (∼1 wt.% Zn). Atmospheric emissions of Zn increased from 15 g/h to nearly 2.4 kg/h when coal + TDF was combusted. Similarly, emissions of most other metals and metalloids, as well as those of HCl increased when TDF (∼3000 ppm Cl) was added. The enhanced metal emissions might be due to formation of gaseous metal chloride species in the stack gases. On the other hand, emissions of CO decreased slightly, whereas those of NO x , SO 2 , and total particulate matter remained virtually unchanged. These results help in assessing the environmental impact of energy recovery from scrap tires in stoker boilers.

Allanite is present in most samples of the tonalitic Bell Island Pluton, with an average mode near 0.05 wt.%. Allanite occurs as cores in igneous epidote-clinozoisite and exhibits characteristic and consistent zoning patterns. REE-rich cores (All40-70) grade out towards epidote-clinozoisite with REE below electron microprobe detection limits. La, Ce and Pr contents are highest in the REE-rich cores of zoned crystals. Nd and Sm contents both initially increase as total REE decreases and are highest in intermediate zones. Y contents are generally low throughout, but tend to be highest in analyses with A115-20. The zoning behaviour exhibited by the allanite, specifically the rimward increases in Nd, Sm, and Y, cannot be accounted for by simple fractionation and are best explained by increases in allanite/ melt partition coefficients (Kd values) for these elements during crystallization. We propose that the variation in Kd values reflects modification of the allanite structure with changing REE content. These modifications are manifested by changes in colour, extinction, and pleochroism within the zoned crystals and include changes in unit-cell volume and dimensions. The changes in Kd values are large enough to result in crossing REE patterns within single allanite crystals. Fractional crystallization of zoned allanite can have noticeable effects on LREE contents and La/Sm (and almost certainly La/Lu) in magmas. In the Bell Island pluton, 80% of La, but LREE chemistry of the pluton is attributable to statistical sampling error, much of it appears to reflect petrogenetic processes that controlled LREE abundance and, ultimately, allanite mode. One sample of Bell Island tonalite is depleted in LREE and has low La/Lu and La/Sm. These chemical features can be modelled by fractionation of zoned allanite.

Epidote-group minerals rich in rare earth elements (REE), in particular allanite, are common accessory phases in igneous, metamorphic, metasomatic, and sedimentary rocks. Small amounts of REE are present in most epidote-group minerals, but in allanite—and the related minerals dissakisite, ferriallanite, dollaseite, khristovite and androsite—the REE are essential structural constituents. An important characteristic of REE-rich epidote-group minerals is that their octahedrally coordinated M sites contain major amounts of divalent cations. This paper summarizes literature data for these minerals and discusses their chemistry, occurrence, phase relations, and petrologic and geologic significance. The chapter emphasizes allanite, because it is the most common and best-studied of the REE-rich epidote-group minerals. Epidote-group minerals contain isolated silicon tetrahedra and corner-sharing groups of two tetrahedra, and are thus assigned to the disilicate or sorosilicate structural family (for a detailed description of the structure, see Franz and Liebscher 2004). The epidote-group structural formula is A2M3(SiO4)(Si2O7)(O,F)(OH), or in a simplified form A2M3Si3O11(O,F)(OH), in which A = Ca, Sr, Pb2+, Mn2+, Th, REE3+, and U, and M = Al, Fe3+, Fe2+, Mn3+, Mn2+, Mg, Cr3+, and V3+ (Deer et al. 1986). There are two structurally different A sites, A(1) and A(2), with different coordination numbers, and there are three different M sites, M(1), M(2), and M(3), which are all octahedrally coordinated (Ueda 1955; Dollase 1971). In epidote-group minerals, trivalent REE are accommodated in the A sites, which in endmember epidote both contain Ca. The incorporation of REE3+ is commonly charge balanced by a divalent cation (Fe2+, Mn2+, Mg) substituted for a trivalent one in the M sites (Table 1 …

An effective undergraduate mineralogy course provides students with a familiarity and understanding of minerals that is necessary for studying the Earth. This paper describes our strategy for integrating the disparate topics covered in a mineralogy course and for presenting them in a way that facilitates an understanding of mineralogy that enables students to apply it in subsequent courses and research. Our strategy is to organize the course into a well-integrated sequence of lectures, demonstrations and laboratory exercises that unfolds the material logically and at a pace that is responsive to the students' needs. The course begins with six weeks on crystal chemistry, then five weeks covering analytical methods for characterizing minerals and ends with five weeks on the silicates. This order facilitates a progression of learning from the basic concepts to the more advanced and allows us to reinforce the concepts of crystal chemistry during the final section on the silicates. Optical mineralogy is almost...

Fly ash from a coal-fired power plant was investigated to obtain detailed information on its physical and chemical properties, and to gain an understanding of potential environmental and health impacts associated with itsdisposal in landfills. The studied material was produced through combustion of Illinois Basin coal and trapped within the power plant by an electrostatic precipitator. It is a fine-grained, low-Ca fly ash containing primarily SiO 2 , Al 2 O 3 , and Fe 2 O 3 , and is enriched in many toxic elements (e,g., Be, Zn, As, Cd, Tl, Pb, and U) by a factor of up to 30 relative to coal. The ash consists of mainly hematite, magnetite, mullite, quartz, and amorphous material. These constituents occur mostly as spherical particles with diameters of less than 13 μm. We examined the physical, chemical, and structural characteristics of individual fly ash particles by scanning and transmission electron microscopy and electron probe microanalysis. The results demonstrate that, with the exception of complex plerospheres, individual particles are chemically fairly homogeneous, but a pronounced compositional variation exists among particles with similar physical and structural attributes. Electron microprobe data document that several trace elements, including U, are partitioned into the Fe-rich particles. Transmission electron microscopy revealed that various types of small (

Ganterite, [Ba 0.5 (Na,K) 0.5 ]Al 2 (Si 2.5 Al 1.5 O 10 )(OH) 2 , the barium-dominant analogue of muscovite, was discovered in the crystalline basement rocks of the Berisal Complex, Simplon Region, Switzerland. Examples of this new rock-forming mica are found in bands and lenses of white-mica schist, and in a leucocratic zoisite–celsian gneiss. Samples of the schist, and especially of the celsian-bearing gneiss, are characterized by high whole-rock Ba contents of up to 15 wt.% BaO. The mineral paragenesis consists of zoisite, quartz, plagioclase, apatite, zircon and amphibole in the schist, and zoisite, celsian, quartz, margarite ± armenite in the gneiss. Ganterite is light grey to silver, has a vitreous luster, a perfect {001} cleavage, a laminated fracture, and a flexible tenacity. Mohs hardness, determined from micro-hardness indentations, is 4–4½. The mica is biaxial (−), α 1.600 (calc.), β 1.619, γ 1.622, and 2 V (meas.) equal to 42.5 ± 2°. The calculated density of the most Ba-rich ganterite is 3.11 g/cm 3 . Single crystals typically are 0.5 by 0.15 mm (or less), and occur in small bands, lenses or clusters 0.5 to 10 cm in thickness. Ganterite is monoclinic, space group C2/ c , Z = 4, a 5.212(1), b 9.046(2), c 19.978(4) A, β 95°48′, V 937.6 A 3 , corresponding to a 2 M 1 polytype. The strongest seven powder-diffraction lines [ d in A(I)( hkl )] are: 2.571(100)(131,202), 2.602(95)(130,131), 1.5054(91)(060,2010), 3.737(77)(023), 3.887(76)(113), 4.481(71)(110), and 3.495(71)(114). The new mineral species is named after the geographical region in which it was found.

Nous avons etudie la composition chimique de la muscovite riche en barium et de la ganterite provenant du socle cristallin du complexe du Berisal et de la region du Simplon, en Suisse. Les compositions de mica blanc provenant de differentes localites ou la teneur en Ba est elevee montrent l'existence d'une solution solide etendue entre la ganterite et la muscovite. Ainsi le materiel est ideal pour l'etude des consequences cristallochimiques liees a l'introduction de barium dans la muscovite dioctaedrique. On trouve les micas blancs riches en barium dans deux unites lithologiques a composition chimique dominees par SiO 2 + Al 2 O 3 + BaO + K 2 O ′ Na 2 O et SiO 2 + Al 2 O 3 + BaO + CaO. La premiere est un schiste a mica blanc compose de mica blanc + quartz + mineraux du groupe de l'epidote et se presentant sous forme de lentilles ou de couches intercalees dans des gneiss a oeillets a deux micas et grenat, des gneiss a zoisite et biotite et des gneiss a zoisite et celsiane. Le deuxieme type de roche propice est un gneiss a zoisite et celsiane caracterise par l'assemblage mineralogique mica blanc + zoisite + celsiane + quartz + margarite. Au sein des deux lithologies, les micas blancs riches en barium sont syncinematiques, et d'apres les observations petrologiques, le barium etait present dans ces roches au depart, ou introduit durant le paroxysme metamorphique alpin. Les concentrations en Ba des micas blancs varient entre 3.6 et 18.2% de BaO (poids). Une forte teneur en Ba est toujours associee a une forte teneur en Al, et de faibles concentrations en K et Si. La plus forte teneur en Ba est accouplee a un enrichissement en Na, mais des correlations similaires pour le Fe ou le Mg ne sont pas observees. L'accomodation des ions Ba 2 + dans les micas est generalement accomplie selon les vecteurs d'echange (1) [Ba][ [ I V ] Al][K] - 1 [Si] - 1 ou (2) [Ba][Fe,Mg][K] - 1 [Al] - 1 . Pourtant, les donnees presentees ici montrent que le vecteur d'echange (2) n'est pas important dans la solution solide entre la muscovite et la ganterite. En outre, le vecteur (1) n'opere que si K depasse 0.53 atomes par unite formulaire (Ba < 0.32). Pour de plus fortes concentrations en Ba, un deuxieme vecteur d'echange distinct [Na][K] - 1 opere egalement dans le site interfoliaire. Pour de fortes concentrations en Ba dans les micas blancs dioctaedriques, il y a une solution solide d'echange etendue impliquant les ions Na + , K + , et Ba 2 + . Dans les mineraux ou l'echange entre les elements alcalins et alcalino-terreux est observe (exemple: les feldspaths), une lacune de miscibilite existe, en general. Une telle lacune n'est pas observee dans le systeme ganterite - muscovite - paragonite, rendant le systeme probablement unique. Les raisons permettant de tels echanges ne sont pas entierement comprises. D'ailleurs, la composition de la roche totale ne joue pas de role important.

Small syngenetic exhalative Fe-Mn deposits embedded in Triassic marbles of the Suretta, Starlera, and Schams nappes (Eastern Swiss Alps) were subjected to a Tertiary regional metamorphism under blueschist- to greenschist-facies conditions. In one of the deposits (at Fianel, Val Ferrera), this polyphase metamorphism led to the formation of quartz1dolomite veinlets containing beryl, scheelite-powellite, paraniite-(Y), monazite- (Ce), fluorapatite, bergslagite, fluor-romeite, and antimonian betafite; these veinlets crosscut dolomite breccia lenses that are embedded in hematite-quartz-carbonate ores. Scheelite- powellite displays a continuous range of compositions between 28 and 70 mol% CaMoO4; its As2O5 contents range from 0.73 to 3.96 wt%, and are positively correlated with the Y2O3 contents that vary between 0.33 and 2.47 wt%. The scheelite-powellite grains display a two-stage chemical zoning: stage A generally produced a core and a rim that, relative to the core, is richer in W, As, and Y. During the second stage (stage B), W-rich scheelite- powellite replaces stage-A grains along fractures and rims. Crystals of paraniite-(Y), ide- ally (CaWO4)2·YAsO4, occur as small inclusions (51 mm) in stage-B scheelite-powellite. The Fianel deposit is only the second locality where paraniite-(Y) has been reported. The paraniite-(Y) from Fianel displays, like the type material, no polysomatic stacking fault in the scheelite-YAsO4 layering. At Fianel, paraniite-(Y) is characterized by elevated Mo contents, and seems to have crystallized under influence of W- and LREE-rich fluids during stage B, i.e., during the metasomatic replacement of Y- and As-rich scheelite-powellite produced in stage A.

An AEM ratio technique for the analysis of 25 elements in finely zoned natural zirconolite was used in conjunction with electron diffraction and imaging techniques to examine the effects of alpha-decay damage on zirconolites from Bergell, Switzerland-Italy and Adamello, northern Italy. Comparison of AEM and EPMA results confirms that the AFM technique can be used to obtain accurate information on the chemical formula of zirconolite. The TEM images and diffraction patterns in this study are analogous to those of previous authors. They support the proposition that radiation damage ingrowth can be adequately described by the accumulation and overlap of isolated alpha-recoil collision cascades, producing progressively larger amorphous domains. Careful determination of Th and U contents by AEM gives an accurate indication of the dose range of the crystalline-amorphous transformation. For the samples from Bergell and Adamello, the transformation occurs over a dose range of 0.05 × 10 16 to just over 1 × 10 16 a/mg, consistent with studies of synthetic zirconolite doped with 238 Pu or 244 Cm. The Bergell zirconolites all exhibited diffraction patterns characteristic of the zirconolite-2M. Those grains containing REE and Th+U contents up to ≈0.1 and ≈0.03 atoms per formula unit, respectively, exhibit a high level of crystallographic perfection. While those grains containing ≈0.2 REE and 0.06 Th+U atoms per formula unit, exhibit twinning and stacking disorder.

Ambient airborne particulate matter is known to cause various adverse health effects in humans. In a recent study on the environmental impacts of coal and tire combustion in a thermal power station fine crystals of PbSO4 (anglesite), ZnSO4•H2O (gunningite), and CaSO4 (anhydrite) were identified in the stack emissions. Here, we have studied the toxic potential of these sulfate phases as particulates and their uptake in human alveolar epithelial cells (A549). Both PbSO4 and CaSO4 yielded no loss of cell viability, as determined by the WST-1 and NR assays. In contrast, a concentration-dependent increase in cytotoxicity was observed for Zn sulfate. For all analyzed sulfates, an increase in the production of reactive oxygen species (ROS), assessed by the DCFH-DA assay and Electron Paramagnetic Resonance (EPR), was observed, although to a varying extent. Again, Zn sulfate was the most active compound. Genotoxicity assays revealed concentration-dependent DNA damage and induction of micronuclei for Zn sulfate and, to a lower extent, for CaSO4, whereas only slight effects could be found for PbSO4. Moreover, changes of cell cycle were observed for Zn sulfate and PbSO4. It could be shown further that Zn sulfate increased the nuclear factor kappa-B (NF-κB) DNA binding activity and activated c-Jun N-terminal kinases (JNK). During our TEM investigations, no effect on the appearance of the A549 cells exposed to CaSO4 compared to the non-exposed cells was observed, and in our experiments only one CaSO4 particle was detected in the cytoplasm. In the case of exposure to Zn sulfate, no particles were found in the cytoplasm of A549 cells, but we observed a concentration-dependent increase in the number and size of dark vesicles (presumably zincosomes). After exposure to PbSO4, the A549 cells contained isolated particles as well as agglomerates both in vesicles and in the cytoplasm. Since these metal-sulfate particles are emitted into the atmosphere via the flue gas of coal-fired power stations, they may be globally abundant. Therefore, our study is of direct relevance to the population living near such power plants.

Journal of Petrology, 52 (12), ISSN:0022-3530, ISSN:1460-2415

Zirconolite, aeschynite-(Ce), titanite and apatite have been found as minor or accessory minerals in a Ti-rich (TiO2=2.1–4.5 wt.%) hydrothermal vein occurring in dolomite marbles at the contact with a tonalite intrusion of the Tertiary Adamello batholith (northern Italy). The vein consists of four distinct mineral zones, comprising from margin to center: (1) forsterite+calcite, (2) pargasite+calcite+titanite+sulfides, (3) phlogopite +calcite+titanite+sulfides, and (4) titanian clinohumite +spinel+calcite+sulfides. Zirconolite occurs in two vein zones only: in the phlogopite zone it is invariably anhedral, often corroded, and exhibits complex chemical zonation patterns. In the titanian clinohumite zone zirconolite is idiomorphic and characterized by a pronounced discontinous chemical zoning, but shows no evidence of corrosion. The considerable compositional variation observed for zirconolite (in wt.%: ∑(REE2O3)=0.74–16.8, UO2=0.59–24.0, ThO2=0.67–17.1) is due to the zoning, and may be attributed to four major substitutions described by the exchange vectors: 1. (Th, U) (Mg, Fe2+) Ca-1 Ti-1 2. REE Al Ca-1 Ti-1 3. REE Fe2+ (Nb, Ta) Ca-1 Ti-1 4. Hf Zr-1

Contact metamorphic marbles, affected by metasomatic fluids at the contact to the Bergell and Adamello Intrusives, contain various accessory minerals (zirconolite, allanite, titanite, rutile, geikielite, hoegbomite), which provide new evidence for the hydrothermal mobility of Ti and Zr. In both examples, Ti and Zr migrated along with U, Th, Y and REE in a metasomatic fluid rich in potassium. The composition of the main minerals (fluorine-rich phlogopite, pargasite and titanian clinohumite) and the abundance of fluor-apatite demonstrate that fluorine and phosphorus were important components of the fluid. The textural relationships indicate that the formation of the accessory phases is linked to the crystallization of the hydrous minerals.

The research presented here was conducted within the scope of an experiment investigating technical feasibility and environmental impacts of tire combustion in a coal-fired power station. Previous work has shown that combustion of a coal+tire blend rather than pure coal increased bulk emissions of various elements (e.g., Zn, As, Sb, Pb). The aim of this study is to characterize the chemical and structural properties of emitted single particles with dimensions

Epidote-group minerals are monoclinic in symmetry and have topology consistent with space group P21/m and the general formula A2M3(T2O7)(TO4)(O,F)(OH,O). Zoisite is an orthorhombic polymorph of clinozoisite Ca2Al3(Si2O7)(SiO4)O(OH) and is thus not considered a member of the epidote-group. Epidote-group minerals are divided into three subgroups. (1) Members of the clinozoisite subgroup are derived from the mineral clinozoisite Ca2Al3(Si2O7)(SiO4)O(OH) by homovalent substitutions only. The key cation- and anion-sites are A1 = M2+, A2 = M2+, M1 = M3+, M2 = M3+, M3 = M3+, O4 = O2-, O10 = (OH)-. In other words, the dominant valence as listed above must be maintained. (2) Members of the allanite subgroup are REE-rich minerals typified by the eponymous mineral "allanite". This subgroup may be derived from clinozoisite by homovalent substitutions and one coupled heterovalent substitution of the type A2(REE)3+ + M3M2+ → A2Ca2+ + M3M3+. Thus the valences on the key sites are: A1 = M2+, A2 = M3+, M1 = M3+, M2 = M3+, M3 = M2+, O4 = O2-, O10 = (OH)-. (3) Members of the dollaseite subgroup are REE-rich minerals typified by the eponymous mineral "dollaseite". This subgroup may be derived from clinozoisite by homovalent substitutions and two coupled heterovalent substitutions of the type A2(REE)3+ + M3M2+ → A2Ca2+ + M3M3+ and M1M2+ + O4F - → M1M3+ + O4O-2. Thus the valences on the key sites are: A1 = M2+, A2 = M3+, M1 = M2+, M2 = M3+, M3 = M2+, O4 = F-, O10 = (OH)-. The key cation-sites M3 and A1 (and, in principle, M2) determine the root name. In both clinozoisite and allanite subgroups no prefix is added to the root name if M1 = Al. The prefixes ferri, mangani, chromo, and vanado indicate dominant Fe3+, Mn3+, Cr3+, and V3+ on M1, respectively. In the dollaseite subgroup no prefix is added to the root name if M1 = Mg. Otherwise a proper prefix must be attached; the prefixes ferro and mangano indicate dominant Fe2+ and Mn2+ at M1, respectively. The dominant cation on A2 (other than Ca) is treated according to the Extended Levinson suffix designation. This simple nomenclature requires renaming of the following approved species: Niigataite (old) = clinozoisite-(Sr) (new), hancockite (old) = epidote-(Pb) (new), tweddillite (old) = manganipiemontite-(Sr) (new). Minor modifications are necessary for the following species: Strontiopiemontite (old) = piemon- tite-(Sr) (new), androsite-(La) (old) = manganiandrosite-(La) (new). Before a mineral name can be assigned, the proper subgroup has to be determined. The determination of a proper subgroup is made by the dominating valence at M3, M1, and A2 expressed as M2+ and or M3+, not by a single, dominant ion (i.e., Fe2+, or Mg, or Al). In addition, the dominant valence on O4: X - or X 2- must be ascertained. (M2+)A2 > 0.50, (M3+)M3 > 0.50 → clinozoisite subgroup, (M3++ M4+)A2 > 0.50, (M2+)M3 > 0.50 → allanite subgroup, {(M2+)M3+M1 - (M3++ M4+)A2 } > 0.50 and (X - )O4 > 0.5 → dollaseite subgroup. Coupled heterovalent substitutions in epidote-group minerals require a special application of the so-called 50 % rule in solid-solution series. (1) Clinozoisite subgroup: The dominant trivalent cation on M3 determines the name, whereas the A2 cation appearing in the suffix has to be selected from among the diva- lent cations. (2) Allanite and dollaseite subgroups: For the sites involved in the charge compensation of a heterovalent substitution in A2 and O4 (i.e. M3 in the allanite subgroup; M3 and M1 in the dollaseite subgroup), identification of the relevant end-member formula must take into account the dominant divalent charge-compensating octahedral cation (M2+) and not the dominant cation

Chemical extraction techniques and scanning electron microscopy were used to study the distribution and behavior of actinides and rare earth elements (REE) in hydrothermal veins at Adamello, (Italy). The six samples discussed in this paper were from the phlogopite zone, which is one of the major vein zones. The samples were similar in their bulk chemical composition, mineralogy, and leaching behavior of major elements (determined by extraction with 9M HCl). However, there were major differences in the extractability of REE and actinides. The most significant influence on the leaching characteristics appears to be the amounts of U, Th and REE incorporated in resistant host phases. Uranium and Th are very highly enriched in zirconolite grains. Actinides were more readily leached from samples with a higher content of U and Th, relative to the amount of zirconolite. The results show that REE and actinides present in chemically resistant minerals can be retained under aggressive leaching conditions.

Titanate ceramics have been proposed as candidate materials for immobilizing excess weapons plutonium. This study focuses on the characterization of a titanate-based ceramic through X-ray diffraction (XRD), electron probe microanalysis, and electron energy-loss spectroscopy (EELS). Three distinct phases have been identified, and their volume fraction was determined from element distribution maps using Scionimage-NIH Analysis software. This analysis revealed that the pyrochlore-group phase betafite (A2Ti2O7) forms the matrix of the ceramic and occupies 90.4% of the volume. Uniformly distributed in this matrix are perovskite (A2Ti2O6) and Hf-enriched rutile (TiO2), which account for 6.4 vol% and 3.1 vol%, respectively. The studied ceramic exhibits a very low porosity (0.3 vol%), which is characterized by small (3+ and Ce4+ in betafite, whereas in perovskite, all Ce is trivalent.

Betafite and zirconolite occur in Ti-rich hydrothermal veins emplaced within dolomite marble in the contact aureole of the Adamello batholith, northern Italy. Zirconolite contains up to 18 wt% ThO2 and 24 wt% UO2, and exhibits strong compositional zoning. Some zirconolite grains were corroded by the hydrothermal fluid. Betafite, the Ti-rich member of the pyrochlore group, often occurs as overgrowths on zirconolite. The betafite is weakly zoned and contains 29-34 wt% UO2. In terms of end -members, betafite contains approximately 50 mole percent CaUTi2O7 and is the closest known natural composition to the pyrochlore phase proposed for use in titanate waste forms. Amorphization and volume expansion of the betafite caused cracks to form in the enclosing silicate mineral grains. Backscattered electron images reveal that betafite was subsequently altered along crystal rims, particularly near the cracks. EPMA data reveal little difference in composition between altered and unaltered areas, except for lower totals, suggesting that alteration is primarily due to hydration. The available evidence demonstrates that both betafite and zirconolite retained actinides for approximately 40 million years after the final stage of vein formation. During this time, betafite and zirconolite accumulated a total alpha -decay dose of 3-4 x 1016 and 0.2-2 x 1016 α/mg, respectively.

Euhedral crystals of purple spinel are associated with calcite and forsterite in the central zone of composite metasomatic veins of the Adamello contact aureole (Northern Italy). In thin section, spinel is generally colorless, but exhibits concentric zones of dark brown color. These zones are aligned parallel to prominent crystal faces and contain abundant anisotropic, lath-shaped inclusions with their long axis oriented in the six directions of spinel. This orientation results from the alignment of {001}Geik and the {111}Sp crystallographic planes. The small (up to approximately 20 × 1 μm) inclusions were identified as geikielite by means of element distribution maps, micro-Raman spectroscopy, and transmission electron microscopy. Electron microprobe data revealed that spinel consists mainly of MgAl2O4, with only minor amounts of other components. The overall chemical variation within individual crystals is characterized by a continuous increase in FeOtot and ZnO from center to rim (0.6–2.1 wt% and

Uranium-rich microlite, a pyrochlore-group mineral, occurs in 440 Ma old lithium pegmatites of the Mozambique Belt in East Africa. Microlite exhibits a pronounced growth zoning, with a U-free core surrounded by a U-rich rim (UO{sub 2} up to 17 wt.%). The core exhibits conjugate sets of straight cracks (cleavage planes) which provided pathways for a late-stage U-enriched pegmatitic fluid which interacted with the U-free microlite to produce a distinct U enrichment along the cracks and led to the formation of the U-rich rim. Following the stage of U incorporation into microlite, a second generation of hydrothermal fluids deposited mica along the cleavage planes. Subsequent to these two hydrothermal stages, the host rock was uplifted and subjected to intense low-temperature alteration during which Na, Ca and F were leached from the microlite crystals. This alteration also led to a hydration of microlite, but there is no evidence of U loss. These low-temperature alteration effects were only observed in the U-rich rim which is characterized by a large number of irregular cracks which are most probably the result of metamictization, as indicated by electron diffraction images and powder X-ray patterns. The pyrochlore-group minerals provide excellent natural analogues for pyrochlore-based nuclear waste forms, because samples of variable age and with high actinide contents are available.