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Introduction: Upon passage through Earth’s atmosphere, micrometeorites undergo variable degrees of melting and evaporative processes [1-2]. Amongst the textural and chemical groups of cosmic spherules, i.e. fully melted micrometeorites, a subset of particles displays anomalously high degrees of vaporization, as deduced from their chemical and isotopic composition. Previous research proposed a classification scheme for such cosmic spherules, based on the extent of evaporative loss undergone (‘Normal chondritic’ – ‘CAT-like’ – ‘High Ca-Al’) [3]. Although originally developed for vitreous cosmic spherules, this classification can also be applied to other petrographic types [4]. We have characterized a selection of refractory element-enriched cosmic spherules from Widerøefjellet (Sør Rondane Mountains, East Antarctica) for their textural features, major and trace element concentrations, as well as oxygen isotopic composition. The chemical modifications that these particles underwent upon atmospheric entry have been investigated in detail, and potential overlaps with other classification systems, based on textural rather than chemical characteristics [5], are also addressed in this study. Methodology: The cosmic spherules characterized in this study were collected from Mount Widerøe (Widerøefjellet), Sør Rondane Mountains (Dronning Maud Land, East Antarctica) during a field campaign in 2018. In total, 78 particles were picked from non-magnetic sediment fractions based on their white to transparent colour, a typical characteristic for highly vaporized cosmic spherules. A more refined selection was made following SEMEDS analysis at the Vrije Universiteit Brussel, based on elevated major refractory element (Al, Ca, Ti) concentrations. Reliable major and trace element compositions were obtained for 35 cosmic spherules using a Teledyne Photon Machines Analyte G2 ArF* excimer-based laser ablation system coupled to a Thermo Scientific Element XR double-focusing sector-field ICP-MS unit at the Department of Chemistry of Ghent University (Belgium). For the assessment of the oxygen isotopic composition in the cosmic spherules, a total of 23 pre-characterized samples were analysed using a CAMECA IMS 1270 Secondary-Ion Mass Spectrometer (SIMS) at the Centre de Récherches Pétrographiques et Géochimiques (CRPG, Nancy, France). Results and discussion: The sample set consists of 12 vitreous, 1 cryptocrystalline, 14 barred olivine, 1 porphyritic, 1 scoriaceous and 6 mixed cryptocrystalline/barred olivine particles. In a Fe/Si vs CaO+Al2O3 diagram, 25 particles plot as ‘CAT-like’ and 10 particles plot as ‘Normal chondritic’, while no ‘High Ca-Al’ particles are identified in the sample set studied. The ‘CAT-like’ (8‰ < δ18O < 59‰;) and ‘normal chondritic’(13‰ < δ18O < 52‰) spherules show a remarkably wide spread in oxygen isotopic data, covering and even extending the range in δ18O previously reported in literature for cosmic spherules [6], thus illustrating the severe evaporation that most particles underwent. This hypothesis is further strengthened by anomalously high enrichments in refractory elements (e.g., Al, Ti, Y, Zr and Hf) and REEs (enrichment factors up to 102). Based on their geochemical composition and Δ17O values, the samples analysed were found to derive from ordinary chondritic (OC) or carbonaceous chondritic (CC) precursors, in proportions that are in general agreement with those reported in literature (30% OC – 70% CC) [3]. The low Fe contents (Fe/Si < 0.04 for 77% of the particles) generally observed amongst the particles studied and reported in literature [2-4] were found to originate from two distinct processes: while metal bead formation and subsequent ejection strongly affected the compositions of all chemical groups of cosmic spherules, evaporative loss of Fe (and other major elements) influenced the final compositions of the ‘CAT-like’ and ‘High Ca-Al’ particles to a larger extent. Through combining major and trace element concentrations with oxygen isotope ratio data, processes such as fragmentation, disproportional sampling of specific mineral constituents (including phosphates or refractory phases such as CAIs), differential melting, metal bead extraction, redox shifts and evaporation were identified. Conclusions: Global trends observed in this work suggest that elemental and isotopic fractionation may cooccur in certain cases, but are decoupled in other. Based on specific element concentrations (e.g., Sr, Zr, Ba, Th, U) and ratios (e.g., Fe/Mg, CaO+Al2O3/Sc+Y+Zr+Hf), both ‘CAT-like’ and ‘High Ca-Al’ cosmic spherules may represent a continuum between the mineral endmembers, sampling a variety of both primitive and differentiated parent bodies that experienced variable degrees of evaporation. References: [1] Rietmeijer F. J. (2000) Meteoritics & Planetary Science 35(5):1025–1041. [2] Lampe S. et al. (2022) Geochimica et Cosmochimica Acta 324:221–239. [3] Cordier et al. (2011) Geochimica et Cosmochimica Acta 75:5203–5218. [4] Goderis et al. (2020) Geochimica et Cosmochimica Acta 270:112–143. [5] Taylor et al. (2000) Meteoritics & Planetary Science 55:651–666. [6] Suavet et al. (2010) Earth and Planetary Science Letters 293(3-4):313–320.

Introduction: The geological record contains scarce evidence for airbursts, the most common type of hypervelocity impact events. During airbursts, impactors of 50 to 150 m in size are fragmented and vaporized during atmospheric entry, as exemplified by the Tunguska and Chelyabinsk events [1]. In recent years, meteoritic debris resulting from such low-altitude airbursts has been found on various locations across Antarctica (cf. summary in [2]). Fine-grained (

Since the development of atomic spectrometry, trace element and isotopic analysis has been mainly based on the monitoring of atomic spectra and monoionic species. However, according to the literature and considering the current instrumental developments, it seems that some of the remaining challenges in this field can be mitigated via the measurement of molecular spectra or of polyatomic ions. This review discusses recent advances in three of the most important atomic techniques (laser-induced breakdown spectrometry, high-resolution continuum source atomic absorption spectrometry and inductively coupled plasma mass spectrometry) and how the monitoring of such molecules or polyatomic ions containing the target analyte enables attaining better selectivity and opens new ways to determine non-metals and to obtain isotopic information.

Particulate matter (PM) emitted in the steel production and cement industry, as well as in the transport and energy production sector, possesses enhanced magnetic properties which enable to delineate the impact of airborne pollution once the particles have deposited onto the Earth’s surface. Topsoil magnetic susceptibility, for instance, has been shown a suitable parameter for airborne pollution monitoring in areas with homogeneous soil type and land use. However, when study areas compri se multiple types of land use , the distribution of magnetic particles down t he soil profile can vary strongly and im pede reliable investigation of pollution impact s. Here, we demonstrate how an adaptive approach involving depth-integrated magnetic susceptibility records can mediate adverse effects of varied land use on topsoil magnetic records for pollution studies (Declercq et al., 2020). Furthermore, in tandem with other receptors of magnetic PM (strawberry and grass leaves, plastic coated cardboards (PCCs) and wiped anthropogenic surfaces), long-term variations captured in soil magnetic records were compared to short-term pollution impacts. Although this approach enables to reliably discriminate spatiotemporal variations in airborne pollution impacts, a straightforward means to relate environmental magnetic signatures more directly to specific emission outputs, and pollutant sources - facilitating the development of control measure strategies - remains lacking. To this end, we characterised the physicochemical properties of PM generated by the largest emitter of magnetic PM in our study area, a steel mill. Particular PM loads involved in different steps of the steel production process (crude iron ore, sinter plant, blast furnace and steel mill), as well as ambient PM collected on PCCs nearby the factory, were magnetically, morphologically and chemically characterized and mutually compared. Source-specific fingerprints facilitated the interpretation of magnetic pollution impacts and revealed how emissions from the blast furnace and steel mill strongly affected the observed magnetic signatures in the environment. We show how the presented magnetic approach supports spatial investigation of source-specific airborne pollution impacts, both on the short and long term.

The performance of a mixture of CH3F/He (1/9) as a reaction gas for the determination of As in biological fluids using a quadrupole ICP-MS instrument has been explored. A simple (dilute-and-shoot) interference-free method has been developed to quantify As concentrations at trace and ultra-trace levels in matrices with a high Cl content. As+ reacts with CH3F (through CH3F addition, followed by HF elimination) with high efficiency forming AsCH2 + as the primary reaction product, which can be monitored at a mass-to-charge ratio of 89, free from the Cl-based interferents (e.g., 40Ar35Cl+ and 40Ca35Cl+) that hamper the monitoring of 75As+. Matrix effects are overcome by the use of Te as an internal standard and the addition of 3% v/v ethanol to all samples and calibration standard solutions. The method presented was validated by analysing a set of reference materials (blood, serum and urine) and by assessing As recovery from a set of real blood samples. With this method, the limit of detection was calculated to be 0.8 ng L-1 As, favourably comparable to the vast majority of values reported in the literature, even with those obtained using more sophisticated sector-field instrumentation.

The increase in the use of SiO2 nanoparticles (NPs) is raising concern about their environmental and health effects, thus necessitating the development of novel methods for their straightforward detection and characterization. Single particle ICP-mass spectrometry (SP-ICP-MS) is able to provide information on the size of NPs, their particle number density and mass concentration. However, the determination of Si via ICP-MS is strongly hampered by the occurrence of spectral overlap from polyatomic species (e.g., CO+ and N2+). The use of tandem ICP-MS (ICP-MS/MS) enables interference-free conditions to be obtained, even in the most demanding applications. Upon testing several gases, the use of CH3F (monitoring of SiF+, mass-shift approach) and of H2 (monitoring of Si+, on-mass approach) were demonstrated to be the most suitable to overcome the spectral interference affecting ultra-trace Si determination (LoD < 15 ng L-1). By using these approaches, SiO2 NPs (ranging between 80 and 400 nm) can be detected and characterized. For SiO2 NPs > 100 nm, it was possible to provide accurate results in a straightforward way, as the signals they give rise to are well resolved from those of the background. In the case of 80 and 100 nm NPs, the use of a simple deconvolution approach following a Gaussian model was needed to characterize SiO2 NPs apparently showing incomplete distributions as a result of the presence of the background signal. Overall, the methods developed using SP-ICP-MS/MS are sensitive and selective enough for the interference-free determination of Si at ultra-trace levels, also in the form of SiO2 NPs.

Item does not contain fulltext Alkaline phosphatase (ALP), an enzyme involved in mineralization of bone, is incorporated into three hydrogel biomaterials to induce their mineralization with calcium phosphate (CaP). These are collagen type I, a mussel-protein-inspired adhesive consisting of PEG substituted with catechol groups, cPEG, and the PEG/fumaric acid copolymer OPF. After incubation in Ca-GP solution, FTIR, EDS, SEM, XRD, SAED, ICP-OES, and von Kossa staining confirm CaP formation. The amount of mineral formed decreases in the order cPEG > collagen > OPF. The mineral:polymer ratio decreases in the order collagen > cPEG > OPF. Mineralization increases Young's modulus, most profoundly for cPEG. Such enzymatically mineralized hydrogel/CaP composites may find application as bone regeneration materials. 01 augustus 2012

The Denizli Basin in the West Anatolian Extensional Province in western Turkey is well-known for its numerous travertine occurrences. A combined sedimentological, diagenetic and geochemical investigation is executed on the Ece and Faber travertines of the Ballk area, the largest travertine site in the Denizli Basin. The first aim of this study is the reconstruction of a three-dimensional geo-model in combination with a detailed sedimentological description from fabric to lithotype, lithofacies and geobody scale, with a focus on integrating pore-typing. The second aim involves the delineation of the CO2-origin of ancient travertine precipitating waters. Peloidal, phyto and dendritic lithotypes dominate the studied travertines and honeycomb and bacteriform shapes and encrusted bacterial or fungal filaments related to their fabrics suggest a microbial influence. The environment of travertine precipitation evolved from dominantly sub-aqueous, as represented by the sub-horizontal and biostromal reed travertine facies, to dominantly sub-aerial in a thin water film, resulting in the cascade, waterfall and biohermal reed travertine facies. A general progradation of the travertine mound is indicated by the occurrence of stacked waterfall travertines. This results in sigmoidal clinoforms inside a general mound boundary configuration. Strontium and oxygen-carbon isotope signatures of the travertines point to a mixing mechanism of palaeofluids with deeply originated, heavy carbon CO2 with lighter carbon CO2 of shallow origin. These deposits can thus be considered as endogenic travertines. Carbonates of the Lycian Nappes acted as main parent carbon source rocks. The relative contribution of the lighter carbon isotopes is most likely to have originated from organic matter or soil CO2. This study provides a unique three-dimensional insight into the Ballk travertine architecture that potentially can be used as an analogue for subsurface travertine reservoirs worldwide and illustrates the importance of the combined use of C-13 and Sr-87/Sr-86 signatures in the delineation of the CO2-origin of travertine precipitating waters.

The Denizli Basin in the West Anatolian Extensional Province in western Turkey is well-known for its numerous travertine occurrences. A combined sedimentological, diagenetic and geochemical investigation is executed on the Ece and Faber travertines of the Ballık area, the largest travertine site in the Denizli Basin. The first aim of this study is the reconstruction of a three-dimensional geo-model in combination with a detailed sedimentological description from fabric to lithotype, lithofacies and geobody scale, with a focus on integrating pore-typing. The second aim involves the delineation of the CO2-origin of ancient travertine precipitating waters. Peloidal, phyto and dendritic lithotypes dominate the studied travertines and honeycomb and bacteriform shapes and encrusted bacterial or fungal filaments related to their fabrics suggest a microbial influence. The environment of travertine precipitation evolved from dominantly sub-aqueous, as represented by the sub-horizontal and biostromal reed travertine facies, to dominantly sub-aerial in a thin water film, resulting in the cascade, waterfall and biohermal reed travertine facies. A general progradation of the travertine mound is indicated by the occurrence of stacked waterfall travertines. This results in sigmoidal clinoforms inside a general mound boundary configuration. Strontium and oxygen-carbon isotope signatures of the travertines point to a mixing mechanism of palaeofluids with deeply originated, heavy carbon CO2 with lighter carbon CO2 of shallow origin. These deposits can thus be considered as endogenic travertines. Carbonates of the Lycian Nappes acted as main parent carbon source rocks. The relative contribution of the lighter carbon isotopes is most likely to have originated from organic matter or soil CO2. This study provides a unique three-dimensional insight into the Ballık travertine architecture that potentially can be used as an analogue for subsurface travertine reservoirs worldwide and illustrates the importance of the combined use of δ13C and 87Sr/86Sr signatures in the delineation of the CO2-origin of travertine precipitating waters. © 2015 The Authors. Sedimentology and 2015 International Association of Sedimentologists.

The Denizli Basin is a fault-bounded Neogene-Quaternary depression located in the Western Anatolian Extensional Province, Western Turkey. The basin is a unique geological site with abundant active and fossil (Quaternary) travertine and tufa deposits. Fluid inclusion microthermometry and isotopic analysis were applied to study the genesis of the Ballk fossil travertine deposits, located in the south-eastern part of the basin. Microthermometry on fluid inclusions indicates that the main travertine precipitating and cementing fluids are characterized by low salinity (

Item does not contain fulltext Interest is growing in the use of hydrogels as bone tissue-engineering (TE) scaffolds due to advantages such as injectability and ease of incorporation of active substances such as enzymes. Hydrogels consisting of gellan gum (GG), an inexpensive calcium-crosslinkable polysaccharide, have been applied in cartilage TE. To improve GG suitability as a material for bone TE, alkaline phosphatase (ALP), an enzyme involved in mineralization of bone by cleaving phosphate from organic phosphate, was incorporated into GG hydrogels to induce mineralization with calcium phosphate (CaP). Incorporated ALP induced formation of apatite-like material on the submicron scale within GG gels, as shown by FTIR, SEM, EDS, XRD, ICP-OES, TGA and von Kossa staining. Increasing ALP concentration increased amounts of CaP as well as stiffness. Mineralized GG was able to withstand sterilization by autoclaving, although stiffness decreased. In addition, mineralizability and stiffness of GG was enhanced by the incorporation of polydopamine (PDA). Furthermore, mineralization of GG led to enhanced attachment and vitality of cells in vitro while cytocompatibility of the mineralized gels was comparable to one of the most commonly used bone substitute materials. The results proved that ALP-mediated enzymatic mineralization of GG could be enhanced by functionalization with PDA.

In this study, we have evaluated the applicability of Nd isotopic analysis for the provenancing of Roman glass and we present a database of Nd isotopic compositions of possible sand raw materials from the western Mediterranean, as a means of comparison for the growing number of isotopic studies on ancient glass. The 143Nd/144Nd isotope ratio of sands is a good indicator for their geological (and sometimes geographical) provenance. The use of the isotopic signature of Nd as a proxy for the source of silica in glass is, however, not always straightforward because of the possible overlap of signatures from different suppliers. ispartof: Archaeometry vol:55 issue:3 pages:449-464 status: published

The accumulation of trace elements (Mg, Mn, Sr, Ba) in Unio pictorum L. mussel shells from Lake Balaton has been assessed using a Laser Ablation (LA) system coupled to either a quadrupole-based or a sector-field inductively coupled plasma–mass spectrometer (ICP – MS), as well as by a combination of micro-drill sampling and solution ICP–MS. The LA–ICP–MS measurements were carried out in the holes made by the micro-drilling system. The longitudinal concentration profiles obtained with the different methods show similar patterns. However, the absolute concentrations determined at individual spots (holes) can be quite different. Especially Ba shows erratic peaks at a very small spatial scale. A paired, two-sample t-test between LA–ICP–MS longitudinal profiles and between LA–ICP–MS and micro-drill/solution ICP–MS profiles indicates that, in most cases, there is no significant difference between the concentration profiles of Ba, Mg, Mn and Sr.Average shell concentrations of Mg, Mn, Sr and Ba, as obtained by LA–ICP–MS and micro-drill/solution ICP–MS, compare well with bulk shell concentrations as obtained by acid digestion/ICP–MS of larger shell pieces. Next to the four elements mentioned above, also the concentrations of Cd, Co, Cr, Cu, Ni, Pb and Zn could be determined by bulk shell analysis. The element concentrations in 11 shells, all sampled at the same site, show a relative standard deviation (RSD) between 2% (Ni) and 46% (Zn).LA–ICP–MS and micro-drill solution ICP–MS are not sensitive enough for the determination of ultra-trace elements in Lake Balaton's mussel shells. We estimated the amount of shell material necessary to determine Ni, Pb, Cr and Cu by micro-drilling ICP–MS (for a concentration that equals 3 times their limit of detection) at, respectively, 0.04, 0.82, 2.7 and 0.4 mg, while the amount sampled by micro-drilling is about 0.06 mg.

The provenancing of Roman natron glass is one of the most challenging problems in the field of archaeometry. Although the use of Sr and Nd isotope ratios and trace element signatures as an indication of provenance has proven promising, there are still many unknowns. In this study, the influence of the different raw materials on the final Sr isotopic composition of Roman natron glass is examined. It is shown that the 87Sr/86Sr ratio in natron glass is significantly influenced by the silicate fraction of the sand used and does not always provide a clear indication of the lime source used.

In this study, we have evaluated the applicability of Nd isotopic analysis for the provenancing of Roman glass and we present a database of Nd isotopic compositions of possible sand raw materials from the western Mediterranean, as a means of comparison for the growing number of isotopic studies on ancient glass. The 143Nd/144Nd isotope ratio of sands is a good indicator for their geological (and sometimes geographical) provenance. The use of the isotopic signature of Nd as a proxy for the source of silica in glass is, however, not always straightforward because of the possible overlap of signatures from different suppliers.

Forty-seven window and vessel glasses from the ‘Great Temple’ at Petra (Jordan), dating to the first/second and fourth centuries CE, were analysed by EPMA for major and minor elements. A subset of 29 samples from Petra and 15 samples from Khirbet et-Tannur were additionally analysed for trace elements, using LA–ICP–MS. Six compositional groups were identified on the basis of the presence of decolouring agents. The majority of the glasses derive ultimately from the Levantine coast, but most of the groups show evidence for highly selective recycling. The observed differences between the two sites could be related to different chronological ranges, functions, relative wealth and trade connections. ispartof: Archaeometry vol:54 pages:997-1022 status: published

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ispartof: The Ancient Near East, A Life! Festschrift Karel Van Lerberghe pages:131-142 ispartof: Orientalia Lovaniensia Analecta vol:220 pages:131-142 status: published

In order to study the effect of anthropogenic substances on freshwater and marine ecosystems and to develop methods to derive water-quality criteria, ecotoxicological testing is required. While toxicity assessments are traditionally based on dissolved metal concentrations, assuming that toxicity is caused by waterborne metal only, it was recently pointed out that also the dietary exposure route should be carefully considered and interpreted in regulatory assessments of zinc. In this context, the aim of this experimental study was to develop a method which allows the uptake of waterborne and dietary zinc by Daphnia magna and the interaction between both exposure routes to be studied. Therefore, the setup of a dual isotopic tracer study was required. During several days, daphnids were exposed to 67Zn and 68Zn via the dietary and the waterborne routes, respectively, and after several time intervals the daphnids were sampled and subjected to isotopic analysis by means of inductively coupled plasma mass spectrometry (ICP-MS). In order to obtain reliable and accurate results for zinc, special care was taken to prevent contamination and to deal with the spectral interferences traditionally hindering the determination of zinc. The figures of merit of both a quadrupole-based ICP-MS instrument equipped with a dynamic reaction cell, and a sector field ICP-MS unit were studied, and it was concluded that by using a sector field mass spectrometer operated at medium mass resolution all interferences could be overcome adequately. Although the set-up of the exposure experiments seems to be rather simple at first sight, it was shown in this work that several (dynamic) variables can have an influence on the results obtained and on the subsequent data interpretation. The importance of these confounding factors was examined, and on the basis of preliminary calculations it became clear that not only the isotopic composition of the daphnids has to be studied-adequate monitoring of the isotopic composition of the dissolved phase and the algae during the exposure of the daphnids is also required to accurately discriminate between uptake from water and from food.

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Regulatory assessments of metals in freshwaters are mostly based on dissolved metal concentrations, assuming that toxicity is caused by waterborne metal only. Little attention has been directed to the toxicity of dietary metals to freshwater invertebrates. In this study the chronic toxicity of dietary zinc to Daphnia magna was investigated. The green alga Pseudokirchneriella subcapitata was exposed for 64 h to a control and three dissolved zinc concentrations, i.e. 23, 28 and 61 µg L-1, resulting in internal zinc burdens in the algae of 130, 200, 320 and 490 µg g-1 dry weight, respectively. These algae were used as a food source in chronic, 21-day bioassays with D. magna in a test medium to which no dissolved zinc was added. None of the treatments resulted in effects on feeding rates or somatic growth of D. magna. In contrast, a significant 40% decrease of total reproduction (number of juveniles per adult) was observed in the 28 and 61 µg L-1 treatments. Time to first brood was not affected, whereas the mean brood size and the fraction of reproducing parent daphnids were reduced from the second brood onwards and the magnitude of these reductions increased with each subsequent brood. The reduced reproduction was accompanied with an elevated zinc accumulation in the 61 µg L-1 treatment only, suggesting that total body burden is no good indicator of dietary zinc toxicity. Overall our data suggest that dietary zinc specifically targets reproduction in D. magna through accumulation in particular target sites, possibly cells or tissues where vitellogenin synthesis or processing occur. Further, our data illustrate that the potential importance of the dietary exposure route should be carefully considered and interpreted in regulatory assessments of zinc.

We investigated the lithophile element budgets of both unequilibrated and equilibrated H chondrites using various in-situ techniques such as μXRF, EPMA, LA-ICP-TOF-MS, etc., addressing the effects of thermal metamorphism on their distributions.

The Kokchetav subduction-collision zone is located in the western part of the ancestral Central Asian Orogenic Belt. This zone is built up by the Precambrian Kokchetav microcontinent which includes a HP-UHP metamorphic belt, and the North Kokchetav tectonic zone (NKTZ) which represents an accretionary complex between the Kokchetav microcontinent and the adjacent Stepnyak island-arc. The entire region is widely intruded by Palaeozoic granitoids which were emplaced after the collision of the Stepnyak island-arc with the Kokchetav microcontinent. We present zircon U-Pb ages and Lu-Hf systematics in zircon to better characterize the tectonic evolution of the Kokchetav subduction-collision zone.The Lu-Hf results indicate that the Kokchetav basement rocks are derived from late Neoarchaean - early Palaeoproterozoic (~. 2.5. Ga) crust. For the granite-gneiss basement of the Kokchetav microcontinent, early Mesoproterozoic (Grenville-age, ~. 1.17-1.14. Ga) zircon U-Pb crystallization ages were obtained. For the NKTZ, two main age-components were recognized: (1) an oldest Mesoproterozoic age-component (~. 1.20-1.05. Ga) similar as for the Kokchetav microcontinental zircons, and (2) a younger Early Cambrian (540-520. Ma) or Late Cambrian - Early Ordovician (~. 490-480. Ma) age-component. Th/U ratios (. 0.1) and are typical of a magmatic protolith. The distinction between both zircon types is supported by characteristic cathodoluminescence images. These results confirm previous observations, indicating early Palaeozoic high-grade metamorphism (~. 540-520. Ma) and collisional deformation (~. 490-480. Ma) of the Mesoproterozoic Kokchetav zone as a result of subduction-accretion and collision of the Stepnyak island-arc to the Kokchetav microcontinent. For two additional samples of the Balkashin granitic complex Early Devonian (~. 415-395. Ma) zircon crystallization ages (magmatic Th/U ratios) were obtained. The occurrence of a Mesozoic xenocryst within these leucogranites may indicate that they were emplaced in a continental-arc setting. Refereed/Peer-reviewed

International audience; A record of Pb isotopic compositions and Pb and Ba concentrations are presented for the EPICA Dome C ice core covering the past 220 ky, indicating the characteristics of dust and volcanic Pb deposition in central East Antarctica. Lead isotopic compositions are also reported in a suite of soil and loess samples from the Southern Hemisphere (Australia, Southern Africa, Southern South America, New Zealand, Antarctica) in order to evaluate the provenance of dust present in Antarctic ice. Lead isotopic compositions in Dome C ice support the contention that Southern South America was an important source of dust in Antarctica during the last two glacial maxima, and furthermore suggest occasional dust contributions from local Antarctic sources. The isotopic signature of Pb in Antarctic ice is altered by the presence of volcanic Pb, inhibiting the evaluation of glacial–interglacial changes in dust sources and the evaluation of Australia as a source of dust to Antarctica. Consequently, an accurate evaluation of the predominant source(s) of Antarctic dust can only be obtained from glacial maxima, when dust-Pb concentrations were greatest. These data confirm that volcanic Pb is present throughout Antarctica and is emitted in a physical phase that is free from Ba, while dust Pb is transported within a matrix containing Ba and other crustal elements.

Polymeermaterialen zijn niet meer weg te denken uit ons dagelijks leven. Hun succes is mede te danken aan de mogelijkheid om additieven toe te voegen aan het materiaal waardoor de eigenschappen, zoals o.m. de hardheid, de thermische weerstand en de rekbaarheid, verbeteren. Er bestaat een brede waaier aan additieven, elk met een specifieke functie. Voor de polymeerindustrie is het bijgevolg noodzakelijk om meer dan 60 elementen zowel kwalitatief als kwantitatief te kunnen bepalen en dit in concentraties gaande van percent tot ppb niveau. Ter ondersteuning van de productontwikkeling, de productiecontrole en het kwaliteitsmanagement is elementanalyse zeer belangrijk. In verschillende sectoren worden bovendien nieuwe normen en reglementeringen aangaande het toevoegen van metalen aan polymeren geïntroduceerd of wordt de bestaande regelgeving verstrengd waardoor accurate controle een absolute must is. Hoewel elementanalyse (bepaling van elementen gaande van H tot U) vaak wordt toegepast in de polymeerindustrie voor de hierboven vermelde redenen, is het zo dat de gebruikte analytische methoden zeer verschillend zijn en binnen de Europese Unie niet geharmoniseerd zijn, laat staan wereldwijd. Bovendien worden de gestelde eisen inzake o.m. detectievermogen en analysesnelheid steeds strenger. Dit alles illustreert het belang van de ontwikkeling van betrouwbare, krachtige en praktische methoden voor de bepaling van additieven in polymeren. Een brede waaier aan digestiemethoden alsook aan spectrometrische technieken kan worden ingezet voor de bepaling van (sporen)elementen in polymeren. De doelstelling van dit werk was de ontwikkeling van adequate methoden voor de bepaling van additieven in polymeermaterialen. Hierbij diende telkens een weloverwogen keuze gemaakt te worden van de aan te wenden monstervoorbereiding, de analysemethode en de monsterintroductie (analyse na voorafgaande monsterdigestie of solid sampling).

This work aimed at studying the isotopic composition of the elements strontium (Sr) and lead (Pb), that are present in low concentrations in a large variety of archaeological artefacts. For isotope ratio analysis, inductively coupled plasma-mass spectrometry (ICP-MS) – a powerful technique for the determination of trace elements and isotope ratios – was used. An analytical strategy was developed, consisting of three key steps: (i) the complete dissolution of a small amount of the (solid) archaeological artefacts making use of concentrated mineral acids, allowing a quantitative recovery for Sr and/or Pb to be obtained, (ii) the isolation of Sr or Pb from its concomitant matrix via extraction chromatography, so that a purified Sr or Pb fraction was obtained and a quantitative recovery for Sr or Pb was established, and (iii) the accurate and precise determination of the isotopic composition of Sr and Pb via single-collector ICP-MS (equipped with one detector) and multi-collector ICP-MS (equipped with an array of detectors). The analytical strategy developed was subsequently applied to three archaeological projects. A first project made use of lead isotopic analysis for provenance determination of metallic artefacts in order to obtain insight into the metal trading network and the trade routes between the Roman Empire and the Indian subcontinent in the period 1st century BC – 2nd century AD. In a second project, lead isotopic analysis allowed to identify the sources of high lead concentrations retrieved in the bone tissue of infants from a Roman settlement. It was shown that the lead present in the infant bone tissue is a mix of lead originating from (i) the process of diagenesis – post-mortem lead exchange between bone and soil – and (ii) lead-enriched food consumed by the mother. A third project aimed at obtaining insight into the heterogeneity of the populations of two grave fields. An explorative study was carried out to distinguish individuals that lived locally and individuals that migrated during their life. For this purpose, the dental tissues (enamel and dentine) of a number of individuals were submitted to strontium isotopic analysis.