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Brachiopods are usually attached benthic marine invertebrates with a shell (exoskeleton) that archives modifications of the environment via chemical proxies. Growth lines regularly occurring (i.e. excluding random ones) at the shell's surface reflect phenotypically controlled interruptions or changes in secretion (Williams et al., 1997). Modifications in the secretion rate and reorientation of shell elements within the thickness of the shell induce marked changes in shell morphology providing elements for estimating age throughout ontogeny for specimens of Aerothyris kerguelenensis (Davidson 1880, formerly known as Waldheimia kerguelensis Davidson, 1978), from the Southern Indian Ocean. Maxima and minima of deviations from underlying shell spiral growth (SSD), plus maps (SEM-EDS) and Electron Microprobe (WDS) of Mg, S, Ca, Mn, Fe that are components of shells along with Scanning Electron Microscopy (SEM) all show evidence of rhythms at different time scales, including annual ones. Growth rates differ in young and adult forms as well as between dorsal and ventral valves; additionally the amplitudes of Mg peaks are higher early in ontogeny and in the primary shell layer, progressively decreasing with sporadic peaks. Anterior regions of shells are more informative regarding external growth (i.e. major growth marks) and mainly record later events in the life of the individual. Posterior regions are informative for internal morphology (cumulative growth) and reveal Mg bands and related concentrations that are consistent with the main extrema (maxima and minima) observed when using SSD and WDS analyses. Mg/Ca ratios indicate fluctuations in temperature and food supply during the growth period. Seawater temperatures calculated from the oxygen isotope compositions of the secondary layer of calcite in shells of A. kerguelenensis are close to those measured in situ in the environment in which they live. However, the difference in carbon isotope composition between the two studied shells reveal that these specimens record isotopic compositions most likely resulting from a combination of kinetic ‘vital’ isotope effects that may, sometimes, mimic equilibrium values. [ABSTRACT FROM AUTHOR]

Abstract: Technogenic magnetic particles (TMPs) emitted by various industrial sources, such as smelting plants, end up after atmospheric transfer on the soil surface. In the present study, we characterised the origin and composition of such particles emitted by a large iron smelting plant and deposited on particular substrates, namely tombstones, which act as a very interesting and appropriate matrix when compared to soil, tree bark, lichens or attic dust. The isolation and subsequent description of TMPs require a critical step of separation between different components of the sample and the magnetic particles; here, we described an efficient protocol that fulfils such a requirement: it resorts to water suspension, sonication, repeated magnetic extraction, sedimentation, sieving and organic matter destruction at 550°C in some instances. The isolated TMPs displayed a noticeable crystalline shape with variable compositions: a) pure iron oxides, b) iron+Cr, Ni or Zn, and c) a complex structure containing Ca, Si, Mg, and Mn. Using Scanning Electron Microscope Energy Dispersive X-ray (SEM–EDX), we obtained profiles of various and distinct magnetic particles, which allowed us to identify the source of the TMPs. [Copyright &y& Elsevier]

Abstract: Without specific experimental equipment, it is very difficult to sample long-term atmospheric deposits on a pure state. That is why the composition of air-transferred solid material accumulated for 40 years in the 2 m-high walls, pierced with numerous holes of an outdoor public shelter, Grenoble city, France, was studied. An appropriate fractionation procedure allowed to obtain several fractions which were i) a sand fraction (8.3%) (fraction A), ii) a large mass of organic matter corresponding mostly to large fragments (>250 μm) of plant origin (66.7%) (fraction B) or to pollen fraction C (0.4%), iii) a slowly depositing organo-clay fraction (20%) (fractions D1 and D2) and iv) a solution mixed with non-settable particles (4.3%) (fraction E). The composition of each fraction was determined for 20 elements. The sand fraction showed very high concentrations specifically in Cu, Pb and Fe corresponding respectively to 81.5, 48.2 and 35.2% of the samples content in these elements. In contrast, Cd and Zn were mainly accumulated in the fraction B (67.5 and 62.2%, respectively). The scanning electron microscopy coupled to energy dispersive X-ray analysis (SEM-EDX) study of the fraction A showed the presence of large particles bearing Pb and Fe, particles rich in Cu and typical fly ashes originating mostly from iron industry. Most of these particles had a crystalline shape suggesting that they were formed after emission at a high temperature. The Pb–Fe–Cu deposit seen in fraction A likely originates from the neighbouring road surface contaminated by car traffic for several decades. The 206Pb/207Pb ratio (1.146 ± 0.004) showed that in the coarse sandy fraction A, Pb was represented at 65% by non-gasoline lead and 35% by “gasoline” lead emitted before 1999. The fraction A particles can only be transported on a limited distance by high magnitude events. They constitute a large reservoir for Cu and Pb and may play a major role in the long-term contamination of urban soils. [Copyright &y& Elsevier]

Abstract: The elemental composition of the deposit formed on the bark of ash-trees was studied over several months on stems ranging from 3 months to 10 years. For this purpose (1) the total elemental composition of the deposit, (2) the structure and composition of the solid particles and (3) the deposit dry weight per dm2 were studied. Concurrently the part of this superficial deposit washed out by rain during 3.5 months was sampled at each rain event and its elemental composition analyzed. This study shows that the deposit was submitted to an intense turnover, with an average leaching-out flux reaching approximately 27mgdm−2 month−1 and a very low increase of the deposit weight per dm2 during the first five years and almost null afterwards. The origin of this superficial deposit was investigated. The main part (78±10%) was organic matter originating from the atmospheric deposition or from the tree. The inorganic content originated partly from the atmosphere, with geogenic and anthropogenic particles, and also from the tree, in which it was demonstrated by scanning electron microscopy – energy dispersive X-ray that a non-negligible part was obtained from bark transpiration, inducing a superficial deposit, mainly of Ca or K in the area surrounding the lenticels. All those results demonstrate that this bark superficial deposit is a complex matrix which must not be considered as a simple cumulative archive but which seems to be the source of interesting information targeting mostly recent atmospheric pollution pressures, when compared to the bulk of suber integrated particles. [Copyright &y& Elsevier]

Abstract: The deposition of atmospheric elements on and into the bark of 4-year-old Fraxinus excelsior L. was studied. The elemental composition of the suber tissue was established through ICP-MS analysis and the presence of solid mineral particles included in this suber was established and described through SEM-EDX. Fractionation of the suber elements mixture was obtained after ashing at 550°C through successive water (C fraction) and HNO3 2M (D fraction) extraction, leading to an insoluble residue mainly composed of the solid mineral particles (E fraction). The triplicated % weight of C, D and E were respectively 34.4 ±2.7, 64.8±2.7 and 0.8±0.1% of the suber ashes weight. The main component of C was K, of D was Ca. Noticeable amounts of Mg were also observed in D. The E fraction, composed of insoluble particles, was mostly constituted of geogenic products, with elements such as Si, Al, K, Mg, representing primary minerals. E also contained Ca3(PO4)2 and concentrated the main part of Pb and Fe. Moreover, The SEM-EDX analysis evidenced that this fraction also concentrated several types of fly ashes of industrial origin. The study of the distribution between C, D and E was analysed through ICP-MS with respect to their origin. The origin of the elements found in such bark was either geogenic (clay, micas, quartz…), anthropogenic or biogenic (for instance large amounts of solid Ca organic salts having a storage role). As opposed to the E fraction, the C fraction, mainly composed of highly soluble K+ is characteristic of a biological pool of plant origin. In fraction D, the very high amount of Ca++ corresponds to two different origins: biological or acid soluble minerals such as calcite. Furthermore, the D fraction contains the most part of pollutants of anthropic origin such as Zn, Cu, Ni, Co, Cd. As a whole, the fractionation procedure of the suber samples allows to separate elements as a function of their origin but also gives valuable information on distribution and speciation of trace elements. [Copyright &y& Elsevier]

The superficial deposit on the bark surface of several trees (mainly Fraxinus excelsior L.) was sampled in the experimental station of the university campus in Grenoble (France). Its composition was studied by scanning electron microscopy–energy dispersive X-ray emission (SEM–EDX) and, after digestion, by inductively coupled plasma-mass spectrometry (ICP-MS). The deposit was composed of 81.3% ± 7.4 organic matter, 9.4% ± 4.9 of geogenic minerals issued from the atmosphere (atmospheric geogenic fraction: AGF) and 9.3% ± 2.7 of a mixture of elements which was called anthropogenic atmospheric elements fraction (AAEF). The SEM–EDX analysis showed the presence of particles of geogenic compounds such as different types of silicates, phosphates, carbonates, sulphates, oxides and also particles of metals such as iron or of alloys of Fe–Zn, Fe–Ni, Ni–Cr and Ca sulphates or phosphates. Typical spheres of “fly ashes” composed of pure iron or Al-silicates were detected. Using the SEM–EDX analysis of the deposit and the average local soil composition, an empiric formula for the AGF (without polluting elements) was chosen, which presented a clear analogy with the global formula of the upper continental crust. In the same way, a formula for the pure organic matter fraction was chosen. Withdrawing the elements corresponding to these two fractions allows a tentative estimation of the content of the AAEF which was supposed to better represent the elemental anthropogenic contamination issued from the atmosphere. In the station, most of Sb, Cd, Sn, Pb, Cu, V and Zn were found in the AAEF. This AAEF composition was compared to that of the deposit in a highway tunnel where Pb and Cu were at a very high level. The meaning and the limits of the AAEF concept were critically discussed. [Copyright &y& Elsevier]

LA-ICP-MS is a powerful technique requiring minimal sample preparation and providing high spatial resolution which may offer the possibility of analysing trace elements in targeted pristine areas of archaeological bone sections. This would provide invaluable information about an individual's life if combined with the geochemical composition of the teeth from the same individual. However, there is no consensus regarding the calibration to be used for LA-ICP-MS analysis of bone, which is a highly complex organo-mineral tissue. In this study, we tested different calibration approaches (NIST and USGS glass series, synthetic phosphate glass and synthetic phosphate pellet from USGS) on a modern bone. The best method was applied to three Precolumbian skeletons (Lerma Valley, Mexico). These individuals show different degrees of preservation (crystallinity, calcite, F and organic matter content) which have been previously explored at the intra-skeletal level. A bone sample with exceptional preservation from the Dogon Country (Mali) was analysed for comparison. Based on BSE SEM images and element distribution of the bone sections obtained via LA-ICP-MS mapping, quantification of Ca, P, Li, Zn, V, U, Na, Mg, Sr and Ba was performed using LA-ICP-MS spot analysis on areas displaying varying concentration profiles and histological preservation. Although avoiding sampling at the external margin of the bone sections may minimize diagenetic Li, Zn, V, U, Sr and Ba, it was not possible to discriminate biological from diagenetic Sr adsorbed onto the bone crystallites of the best preserved Precolumbian skeleton, whose low crystallinity favored adsorption efficiency. In contrast, the well preserved Dogon sample, as well as the most altered Precolumbian skeletons provided Sr and Ba content roughly similar to concentrations obtained using bulk analysis. LA-ICP-MS can therefore not substitute solution analysis for paleodiet prospect, especially for bones in relatively early state of diagenetic transformations. • NIST612/610 and STDP1500 are appropriate CRMs for analysing bones using LA-ICP-MS. • Ca is the most reliable internal reference for archaeological bone LA-ICP-MS analysis. • SEM images and element distribution maps were used to select sampling spots. • Bone LA-ICP-MS analysis could not discriminate diagenetic from biological Sr. • Bone LA-ICP-MS analysis cannot be used for diet reconstruction using Sr. [ABSTRACT FROM AUTHOR]