Tremolite group minerals could be present in the aggregate used as filler in the mix asphalt floor in the road surfaces and are subject to wear for vehicular traffic and materials ageing.Dust produced by the degradati...Tremolite group minerals could be present in the aggregate used as filler in the mix asphalt floor in the road surfaces and are subject to wear for vehicular traffic and materials ageing.Dust produced by the degradation of asphalt surfaces can disperse tremolite group minerals present in road paving causing exposure by asbestos fiber to an increasing number of people and animals.In recent years,attention has been focused on naturally occurring asbestos(NOA)as the greatest frequency of lung cancer has been observed in environments characterized by rocks and soils rich in Tremolite that characterize asbestos minerals.Asphalt samples object of this study were collected in a motorway segment of the Lombardia Region(north of Italy)for an exposure assessment research on road paving workers.The evaluation was performed using a metrological approach based on petrographic and mineralogical analyses in order to reduce the epidemiologic risks and to define the best treatment strategies on waste management with sustainable costs in fulfilment of Council Directive 67/548/EEC(1967)and EC Regulation 1272/2008(2008)(Paglietti et al.,2016).The fibers are generally not broken down to other compounds in the environment,but asbestos hazard could be related to the occurrence of tremolite fiber in road paving arises when natural weathering processes(e.g.,erosion)or human activities(e.g.,continuous passage of motorized vehicles)separate and break down the fibers,which could be lost into the environment as airborne and easily penetrate into the human respiratory tract(Punturo et al.,2019).Despite this,this work is not an epidemiological risk analysis but obtained data could be useful to other specialists to define the exposure risks.展开更多
Tremolite,a kind of inorganic filler,was modified with a silane coupling agentγ-methacryloxypropyl trimethoxy silane (MPS) in ethanol/ammonia solution.The graft of MPS on tremolite was confirmed by X-ray photoelectro...Tremolite,a kind of inorganic filler,was modified with a silane coupling agentγ-methacryloxypropyl trimethoxy silane (MPS) in ethanol/ammonia solution.The graft of MPS on tremolite was confirmed by X-ray photoelectron spectroscopy (XPS),IR and thermogramitric analysis (TGA) measurements.In addition,contact angle analysis showed that particle surface property was changed from hydrophilicity to hydrophobicity after the modification.Modified tremolite and pure tremolite were blended respectively with PA1010 (p...展开更多
Crocidolite,amosite,anthophyllite,tremolite,actinolite besides the chrysotile serpentine polymorph fall within the classification of asbestos,whose commercial use is banned,and environmental and human exposure levels ...Crocidolite,amosite,anthophyllite,tremolite,actinolite besides the chrysotile serpentine polymorph fall within the classification of asbestos,whose commercial use is banned,and environmental and human exposure levels regulated.However,the cited amphibole species can crystallise in asbestiform or non-asbestiform habit and therefore their morphological characterization has a key role in assessing a reliable asbestos hazard scenario.Furthermore,when a mechanical stress is applied to rocks containing pristine prismatic or acicular amphiboles,these phases can break,originating particles with dimensions and geometrical ratios that would label them as asbestos.Therefore,a normative and scientific crucial gap arise in the classification criteria of a particle as a real asbestiform mineral or as a cleavage fragment(i.e.non-asbestos).The mode of comminution is fundamental for the following quantitative determination of fibres.It is critical because it can affect the morphology and geometric ratios of fibres,inducing positive or negative falses.In this framework,our work was focused on the Scanning Electron Microscopy coupled with Energy Dispersive Spettroscopy(SEM-EDS)analysis of amphiboles with asbestiform and non-asbestiform habit,subject to mechanical stress for three different time intervals,in order to assess how different time lengths of comminution control geometry and morphology of the particles.展开更多
The mantle-genetic pargasites in peridotite inclusion of basalt have been studied, but the mantle-genetic tremolite has not been reported in past studies. Four kinds of as semblage with tremolite in metamorphic perido...The mantle-genetic pargasites in peridotite inclusion of basalt have been studied, but the mantle-genetic tremolite has not been reported in past studies. Four kinds of as semblage with tremolite in metamorphic peridotite from Kuda, Xinjiang will be reported in this note. 1 Kuda ophiolite The Kuda ophiolite occurs in Kunlun orogenetic belt and was formed in the period from Sinian to Early Ordovician. The metamorphic peridotite in ophiolite is a tectonic exotic block napp and is a highly depleted harzburgite, which consists of forsterite (Fo=91), enstatite (En=90—95), chromespinel (Cr/ (Cr+Al)=0.5—0.61) and very little of clinopyroxene. The exsolution lamellae in pyroxene and Kink bandings in olivine can be observed clearly under a microscope. The plastic deformation fabrics, such as free dislocation, dislocation wall and subgrain structure, can also be observed in decorated olivines. The minerals in the studied rock samples are very fresh, which offers a good condition for this study.展开更多
The Liaoning Province in the northeastern part of the North China Craton(NCC) hosts several tremolite jade(nephrite) deposits. Here we investigate the Sangpiyu tremolite jade deposit where the relationship between abu...The Liaoning Province in the northeastern part of the North China Craton(NCC) hosts several tremolite jade(nephrite) deposits. Here we investigate the Sangpiyu tremolite jade deposit where the relationship between abundant graphite inclusions within the jade remains enigmatic. We employ petrography, electron probe microanalysis, X-ray-diffraction, and Raman spectroscopy to characterize the tremolite jade and its inclusion minerals. The Sangpiyu jade is predominately composed of tremolite with minor calcite, dolomite, serpentine, titanite, zoisite, allanite, chlorite,apatite, chromite and graphite. Raman spectroscopy of graphite inclusions shows that the D1/G intensity ratio ranges from 0.78 to 0.88 in deep green samples and from 0.05 to 0.23 in dark green samples. The ranges of D1/(D1 + G) integral area ratio for these types are from 0.0548 to 0.3037 and 0.5528 to 0.7355 respectively. The formation temperature of graphite inclusions in the dark green tremolite jade is computed as 549.8 ℃, whereas that for the deep green sample is about343.2 ℃. Our results suggest that the jade formation occurred in a multi-stage process through the action of hydrothermal fluids and metamorphism possibly in a subduction-related setting at moderate to high temperatures.展开更多
Electronic microprobe analysis showed that all QN samples are mainly composed of tremolite and minor accessory minerals, such as diopside, calcite, serpentinite, and magnetite. According to the cation coefficients, th...Electronic microprobe analysis showed that all QN samples are mainly composed of tremolite and minor accessory minerals, such as diopside, calcite, serpentinite, and magnetite. According to the cation coefficients, the crystallo-chemistrygenesis illustration demonstrates that all QN deposits are contact metasomatic. Depending on the mole percent of Fe^(2+(3+))/(Mg^(2+)+Fe^(2+(3+)) and the content of Cr, Co, and Ni in all QN samples measured by X-ray fluorescence spectroscopy(XRF) and inductively coupled plasma-mass spectrometry(ICP-MS), green and azure-green QNs are characterized as serpentinite-related contact metasomatic deposit(S-type), whereas white, green-white, brown, blue-violet, yellow, and viridis QNs are dolomite-related contact metasomatic deposit(D-type). The assemblages and chemical composition of accessory minerals of the eight-color QN samples show evident characteristics, which reveal four possible ore-forming processes. We also measured trace and rare earth elements(REEs) in these samples through ICP-MS to deduce the origin of and the changes in metallogenic conditions. The chondrite-normalized REE patterns of D-type QN exhibit moderately negative Eu anomalies with moderate light REE enrichment, flat heavy REE(HREE), and low(50)REE concentrations, similar to dolomitic marble. Green QN samples of S-type show enrichment in HREE and moderately negative Eu anomalies, which is consistent with characteristics of dunite. Whereas azure-green QN samples of S-type exhibit a right-dipping V-type curve with severe depletion in Eu(δEu=0.36–0.47), in accordance with the characteristics of gabbro from Yushigou ophiolite in North Qilian mountains. Furthermore, this finding is consistent with the content of trace elements and the petrographic analysis results. On the basis of several significant differences in the characteristic elements, which may have been affected by the metallogenic environment, we inferred the differences in oxygen fugacity and basicity of mineralization environments in different-colored QNs.展开更多
The glasses already found in nature fall into three categories: (1) volcanic glass related to volcanic eruptions, (2) diaplectic glass related to meteoritic impactions or nuclear explosions, and (3) pseudotachylite re...The glasses already found in nature fall into three categories: (1) volcanic glass related to volcanic eruptions, (2) diaplectic glass related to meteoritic impactions or nuclear explosions, and (3) pseudotachylite related to high-speed faulting movements. The volcanic glass, resulting from rapid cooling of high-temperature magma, is closely connected to volcanic rocks and does not contain any water. The diaplectic glass,展开更多
Numerous empirical and experimental studies have documented the consumption of orthopyroxene and production of clinopyroxene in mantle peridotite during carbonatite metasomatism,whereas little attention has been paid ...Numerous empirical and experimental studies have documented the consumption of orthopyroxene and production of clinopyroxene in mantle peridotite during carbonatite metasomatism,whereas little attention has been paid to whether and how olivine is compositionally modified through the same process of carbonatite metasomatism.Here,we present the discovery of well-preserved reaction features in olivine from typical calciocarbonatites from Sri Lanka.The olivine grains experienced serpentinization along the cracks and in their rims and are generally surrounded outwardly by serpentine,tremolite and diopside zones.The inner serpentine zone is dominated by serpentine with tiny magnetite,whereas the mantle tremolite zone is characterized by euhedral tremolite and intergrowth of dolomite with small amounts of serpentine relics and diopside.The outer diopside zone shows spongy texture and commonly encloses olivine,serpentine,tremolite and dolomite,which are also observed in interstitial diopside grains in the carbonatites.Compositional profile analyses reveal that these olivine grains display decreasing FeO and increasing MgO contents and thus elevating Fo values from their cores to the reaction rims,while the serpentine inherits compositions from the olivine.Elemental mapping images demonstrate outward diffusion of Si and Mg in the serpentine zones and contribution of Ca from carbonatite melts during tremolite formation.Further interaction with carbonatite melts produced Si-and Mg-poor and Ca-rich diopside relative to the reactant tremolite.These observations suggest that the interaction with carbonatite melts first transformed olivine to diopside through serpentinization,followed by tremolitization.The diopside formed through olivine-carbonatite melt interaction is anomalously depleted in Na and Al and enriched in Ca,which are distinct from those generated in interactions between orthopyroxene and both carbonatite and silicate melts.This implies that for the first time some wehrlites and clinopyroxenites in the mantle might originate from intense interaction between peridotites(including dunite)and carbonatite melts.This mechanism can be invoked to explain the formation of other global occurrences of wehrlite and clinopyroxenite suites.展开更多
文摘Tremolite group minerals could be present in the aggregate used as filler in the mix asphalt floor in the road surfaces and are subject to wear for vehicular traffic and materials ageing.Dust produced by the degradation of asphalt surfaces can disperse tremolite group minerals present in road paving causing exposure by asbestos fiber to an increasing number of people and animals.In recent years,attention has been focused on naturally occurring asbestos(NOA)as the greatest frequency of lung cancer has been observed in environments characterized by rocks and soils rich in Tremolite that characterize asbestos minerals.Asphalt samples object of this study were collected in a motorway segment of the Lombardia Region(north of Italy)for an exposure assessment research on road paving workers.The evaluation was performed using a metrological approach based on petrographic and mineralogical analyses in order to reduce the epidemiologic risks and to define the best treatment strategies on waste management with sustainable costs in fulfilment of Council Directive 67/548/EEC(1967)and EC Regulation 1272/2008(2008)(Paglietti et al.,2016).The fibers are generally not broken down to other compounds in the environment,but asbestos hazard could be related to the occurrence of tremolite fiber in road paving arises when natural weathering processes(e.g.,erosion)or human activities(e.g.,continuous passage of motorized vehicles)separate and break down the fibers,which could be lost into the environment as airborne and easily penetrate into the human respiratory tract(Punturo et al.,2019).Despite this,this work is not an epidemiological risk analysis but obtained data could be useful to other specialists to define the exposure risks.
文摘Tremolite,a kind of inorganic filler,was modified with a silane coupling agentγ-methacryloxypropyl trimethoxy silane (MPS) in ethanol/ammonia solution.The graft of MPS on tremolite was confirmed by X-ray photoelectron spectroscopy (XPS),IR and thermogramitric analysis (TGA) measurements.In addition,contact angle analysis showed that particle surface property was changed from hydrophilicity to hydrophobicity after the modification.Modified tremolite and pure tremolite were blended respectively with PA1010 (p...
基金financial support of the Analisi delle proprietàmicrostrutturali,chimico-fisiche di materiali inorganicideterminazioni quantitative della composizione mineralogica di materiali naturali e delle proprietàtecniche dei materiali litici Laboratory funds,DISTAV,University of Genoa.
文摘Crocidolite,amosite,anthophyllite,tremolite,actinolite besides the chrysotile serpentine polymorph fall within the classification of asbestos,whose commercial use is banned,and environmental and human exposure levels regulated.However,the cited amphibole species can crystallise in asbestiform or non-asbestiform habit and therefore their morphological characterization has a key role in assessing a reliable asbestos hazard scenario.Furthermore,when a mechanical stress is applied to rocks containing pristine prismatic or acicular amphiboles,these phases can break,originating particles with dimensions and geometrical ratios that would label them as asbestos.Therefore,a normative and scientific crucial gap arise in the classification criteria of a particle as a real asbestiform mineral or as a cleavage fragment(i.e.non-asbestos).The mode of comminution is fundamental for the following quantitative determination of fibres.It is critical because it can affect the morphology and geometric ratios of fibres,inducing positive or negative falses.In this framework,our work was focused on the Scanning Electron Microscopy coupled with Energy Dispersive Spettroscopy(SEM-EDS)analysis of amphiboles with asbestiform and non-asbestiform habit,subject to mechanical stress for three different time intervals,in order to assess how different time lengths of comminution control geometry and morphology of the particles.
基金Project supported by the National Natural Science Foundation of China.
文摘The mantle-genetic pargasites in peridotite inclusion of basalt have been studied, but the mantle-genetic tremolite has not been reported in past studies. Four kinds of as semblage with tremolite in metamorphic peridotite from Kuda, Xinjiang will be reported in this note. 1 Kuda ophiolite The Kuda ophiolite occurs in Kunlun orogenetic belt and was formed in the period from Sinian to Early Ordovician. The metamorphic peridotite in ophiolite is a tectonic exotic block napp and is a highly depleted harzburgite, which consists of forsterite (Fo=91), enstatite (En=90—95), chromespinel (Cr/ (Cr+Al)=0.5—0.61) and very little of clinopyroxene. The exsolution lamellae in pyroxene and Kink bandings in olivine can be observed clearly under a microscope. The plastic deformation fabrics, such as free dislocation, dislocation wall and subgrain structure, can also be observed in decorated olivines. The minerals in the studied rock samples are very fresh, which offers a good condition for this study.
文摘The Liaoning Province in the northeastern part of the North China Craton(NCC) hosts several tremolite jade(nephrite) deposits. Here we investigate the Sangpiyu tremolite jade deposit where the relationship between abundant graphite inclusions within the jade remains enigmatic. We employ petrography, electron probe microanalysis, X-ray-diffraction, and Raman spectroscopy to characterize the tremolite jade and its inclusion minerals. The Sangpiyu jade is predominately composed of tremolite with minor calcite, dolomite, serpentine, titanite, zoisite, allanite, chlorite,apatite, chromite and graphite. Raman spectroscopy of graphite inclusions shows that the D1/G intensity ratio ranges from 0.78 to 0.88 in deep green samples and from 0.05 to 0.23 in dark green samples. The ranges of D1/(D1 + G) integral area ratio for these types are from 0.0548 to 0.3037 and 0.5528 to 0.7355 respectively. The formation temperature of graphite inclusions in the dark green tremolite jade is computed as 549.8 ℃, whereas that for the deep green sample is about343.2 ℃. Our results suggest that the jade formation occurred in a multi-stage process through the action of hydrothermal fluids and metamorphism possibly in a subduction-related setting at moderate to high temperatures.
文摘Electronic microprobe analysis showed that all QN samples are mainly composed of tremolite and minor accessory minerals, such as diopside, calcite, serpentinite, and magnetite. According to the cation coefficients, the crystallo-chemistrygenesis illustration demonstrates that all QN deposits are contact metasomatic. Depending on the mole percent of Fe^(2+(3+))/(Mg^(2+)+Fe^(2+(3+)) and the content of Cr, Co, and Ni in all QN samples measured by X-ray fluorescence spectroscopy(XRF) and inductively coupled plasma-mass spectrometry(ICP-MS), green and azure-green QNs are characterized as serpentinite-related contact metasomatic deposit(S-type), whereas white, green-white, brown, blue-violet, yellow, and viridis QNs are dolomite-related contact metasomatic deposit(D-type). The assemblages and chemical composition of accessory minerals of the eight-color QN samples show evident characteristics, which reveal four possible ore-forming processes. We also measured trace and rare earth elements(REEs) in these samples through ICP-MS to deduce the origin of and the changes in metallogenic conditions. The chondrite-normalized REE patterns of D-type QN exhibit moderately negative Eu anomalies with moderate light REE enrichment, flat heavy REE(HREE), and low(50)REE concentrations, similar to dolomitic marble. Green QN samples of S-type show enrichment in HREE and moderately negative Eu anomalies, which is consistent with characteristics of dunite. Whereas azure-green QN samples of S-type exhibit a right-dipping V-type curve with severe depletion in Eu(δEu=0.36–0.47), in accordance with the characteristics of gabbro from Yushigou ophiolite in North Qilian mountains. Furthermore, this finding is consistent with the content of trace elements and the petrographic analysis results. On the basis of several significant differences in the characteristic elements, which may have been affected by the metallogenic environment, we inferred the differences in oxygen fugacity and basicity of mineralization environments in different-colored QNs.
基金Project supported by the National Natural Science Foundation of China, and this report is one of the results of the NSFC item "Ductile shear zone" (85072)
文摘The glasses already found in nature fall into three categories: (1) volcanic glass related to volcanic eruptions, (2) diaplectic glass related to meteoritic impactions or nuclear explosions, and (3) pseudotachylite related to high-speed faulting movements. The volcanic glass, resulting from rapid cooling of high-temperature magma, is closely connected to volcanic rocks and does not contain any water. The diaplectic glass,
基金financially supported by the Youth Innovation Promotion Association,Chinese Academy of Sciences。
文摘Numerous empirical and experimental studies have documented the consumption of orthopyroxene and production of clinopyroxene in mantle peridotite during carbonatite metasomatism,whereas little attention has been paid to whether and how olivine is compositionally modified through the same process of carbonatite metasomatism.Here,we present the discovery of well-preserved reaction features in olivine from typical calciocarbonatites from Sri Lanka.The olivine grains experienced serpentinization along the cracks and in their rims and are generally surrounded outwardly by serpentine,tremolite and diopside zones.The inner serpentine zone is dominated by serpentine with tiny magnetite,whereas the mantle tremolite zone is characterized by euhedral tremolite and intergrowth of dolomite with small amounts of serpentine relics and diopside.The outer diopside zone shows spongy texture and commonly encloses olivine,serpentine,tremolite and dolomite,which are also observed in interstitial diopside grains in the carbonatites.Compositional profile analyses reveal that these olivine grains display decreasing FeO and increasing MgO contents and thus elevating Fo values from their cores to the reaction rims,while the serpentine inherits compositions from the olivine.Elemental mapping images demonstrate outward diffusion of Si and Mg in the serpentine zones and contribution of Ca from carbonatite melts during tremolite formation.Further interaction with carbonatite melts produced Si-and Mg-poor and Ca-rich diopside relative to the reactant tremolite.These observations suggest that the interaction with carbonatite melts first transformed olivine to diopside through serpentinization,followed by tremolitization.The diopside formed through olivine-carbonatite melt interaction is anomalously depleted in Na and Al and enriched in Ca,which are distinct from those generated in interactions between orthopyroxene and both carbonatite and silicate melts.This implies that for the first time some wehrlites and clinopyroxenites in the mantle might originate from intense interaction between peridotites(including dunite)and carbonatite melts.This mechanism can be invoked to explain the formation of other global occurrences of wehrlite and clinopyroxenite suites.
