74 research outputs found

    Atomic spectrometry update – a review of advances in environmental analysis

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    This is the 34th annual review of the application of atomic spectrometry to the chemical analysis of environmental samples. This Update refers to papers published approximately between August 2017 and June 2018 and continues the series of Atomic Spectrometry Updates (ASUs) in Environmental Analysis that should be read in conjunction with other related ASUs in the series, namely: clinical and biological materials, foods and beverages; advances in atomic spectrometry and related techniques; elemental speciation; X-ray spectrometry; and metals, chemicals and functional materials. The review is not intended to be a comprehensive overview but selective with the aim of providing a critical insight into developments in instrumentation, methodologies and data handling that represent a significant advance in the use of atomic spectrometry in the environmental science

    Atomic spectrometry update – a review of advances in environmental analysis

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    TERMITE: An R script for fast reduction of laser ablation inductively coupled plasma mass spectrometry data and its application to trace element measurements

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    Abstract Rationale High spatial resolution Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) determination of trace element concentrations is of great interest for geological and environmental studies. Data reduction is a very important aspect of LA-ICP-MS, and several commercial programs for handling LA-ICPMS trace element data are available. Each of these software packages has its specific advantages and disadvantages. Methods Here we present TERMITE, an R script for the reduction of LA-ICPMS data, which can reduce both spot and line scan measurements. Several parameters can be adjusted by the user, who does not necessarily need prior knowledge in R. Currently, ten reference materials with different matrices for calibration of LA-ICPMS data are implemented, and additional reference materials can be added by the user. TERMITE also provides an optional outlier test, and the results are provided graphically (as a pdf file) as well as numerically (as a csv file). Results As an example, we apply TERMITE to a speleothem sample and compare the results with those obtained using the commercial software GLITTER. The two programs give similar results. TERMITE is particularly useful for samples that are homogeneous with respect to their major element composition (in particular for the element used as an internal standard) and when many measurements are performed using the same analytical parameters. In this case, data evaluation using TERMITE is much faster than with all other available software, and the concentrations of more than 100 single spot measurements can be calculated in less than a minute. Conclusions TERMITE is an open-source software for the reduction of LA-ICPMS data, which is particularly useful for the fast, reproducible evaluation of large datasets of samples that are homogeneous with respect to their major element composition

    Origin, age, and significance of deep-seated granulite-facies migmatites in the Barrow zones of Scotland, Cairn Leuchan, Glen Muick area

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    Petrological modelling of granulite‐facies mafic and semipelitic migmatites from Cairn Leuchan, northeast Scotland, has provided new constraints on the pressure (P) and temperature (T) conditions of high‐grade metamorphism in the type‐locality Barrow zones. Phase diagrams constructed in the Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O2 system have constrained the P−T conditions of peak metamorphism in the Glen Muick region of the upper sillimanite zone (Sill+Kfs) to have been at least ∼840°C at ∼9 kbar (high‐P granulite facies). These conditions are ∼120°C and ∼3 kbar higher than those recorded by lower sillimanite zone (Sill+Ms) units located only a few kilometres away to the southeast at Glen Girnock, indicating the presence of a significant thermal and barometric high exposed within the Scottish Dalradian, and supporting previous suppositions of a potential tectonic break between the two regions. U–Pb zircon geochronology performed on these mafic migmatites produced ages of c. 540–470 Ma from grains with both igneous and metamorphic morphological characteristics. Their basaltic protoliths likely formed during a period of volcanism dated at c. 570 Ma, associated with passive‐margin extension prior to the onset of Iapetus Ocean closure, and high‐grade metamorphism and partial melting is interpreted to have taken place at c. 470 Ma, synchronous with sillimanite‐grade metamorphism recorded elsewhere in the Dalradian. These high‐grade Cairn Leuchan lithologies are interpreted as representing a fragment of Grampian Terrane lower crust that was exhumed via displacement along a steeply dipping tectonic discontinuity related to the Portsoy–Duchray Hill Lineament, and are not pre‐Caledonian Mesoproterozoic basement, as suggested by some previous studies. Veins within some mafic migmatites in the Cairn Leuchan area, composed almost entirely (>80%) of garnet, with minor quartz, plagioclase, amphibole, and clinopyroxene, are interconnected with leucosomes and are interpreted to represent former garnet‐bearing melt segregations that have been locally drained of almost all melt. Thus, mafic components of the lower crust, currently underlying relatively lower grade metasediments exposed to the southeast, may represent a potential source rock for widely documented, post‐orogenic felsic plutons, sills, and dykes that occur throughout the Grampian Terrane

    U-Pb dating of arc to post-collisional magmatic events in northwestern Anatolia: The Eocene Granitoids in NW Anatolia revisited

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    Northwestern Anatolia contains voluminous Cenozoic magmatic rocks which were emplaced during syn- to-post collisional stages of long-term crustal accretion and extensional stages since the late Paleocene. The Eocene to Late Miocene plutonic and volcanic rocks that are located throughout the Rhodopes, northern Aegean, and the western part of Western Anatolia show generally southward decreasing ages, coupled with an increasing crustal recycling component in their genesis. However, the early Eocene, ∼SW–NE-trending, mafic volcanic and the early Eocene, ∼NW-SE-trending, granitoid belts in the northeastern parts of Western Anatolia do not share these features. We present here new U-Pb zircon ages, whole-rock geochemical analyses, and Sr-Nd isotopic data from the early Eocene NW-SE-trending granitoid belt, together with age data from arc-related pyroclastics in the region, in an effort to resolve these uncertainties.The age data reveal that the post-collisional magmatism along the ∼ NW–SE-trending granitoid belt occurred ∼ 58–41 Ma; i.e. ∼ 30 Myr after the Pontide arc magmatism that was active from ∼ 92–74 Ma. We suggest that the ∼ SW–NE-trending mafic volcanic and the ∼ NW-SE-trending granitoid belts developed in response to break-off of two subducted slabs in the northern Neotethys. In addition, emplacement of the ∼ NW-SE trending granitoid belt may also have been influenced by a zone of weakness related to a series of NW–SE-trending dextral strike-slip shear zones lying from the Kapıdağ shear zone close to the Rhodopes in the NW to the Uludağ shear zone in the SE

    Insights fromsodium into the impacts of elevated pCO2 and temperature on bivalve shell formation

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    Ocean acidification and warming are predicted to affect the ability of marine bivalves to build their shells, but little is known about the underlying mechanisms. Shell formation is an extremely complex process requiring a detailed understanding of biomineralization processes. Sodium incorporation into the shells would increase if bivalves rely on the exchange of Na+/H+ to maintain homeostasis for shell formation, thereby shedding new light on the acid-base and ionic regulation at the calcifying front. Here, we investigated the combined effects of seawater pH (8.1, 7.7 and 7.4) and temperature (16 and 22 °C) on the growth and sodium composition of the shells of the blue mussel, Mytilus edulis, and the Yesso scallop, Patinopecten yessoensis. Exposure of M. edulis to low pH (7.7 and 7.4) caused a significant decrease of shell formation, whereas a 6 °C warming significantly depressed the rate of shell growth in P. yessoensis. On the other hand, while the amount of Na incorporated into the shells of P. yessoensis did not increase in acidified seawater, an increase of Na/Cashell with decreasing pH was observed in M. edulis, the latter agreeing well with the aforementioned hypothesis. Moreover, a combined analysis of the shell growth and sodium content provides a more detailed understanding of shell formation processes. Under acidified conditions, mussels may maintain more alkaline conditions favorable for calcification, but a significant decrease of shell formation indicates that the mineralization processes are impaired. The opposite occurs in scallops; virtually unaffected shell growth implies that shell mineralization functions well. Finding of the present study may pave the way for deciphering the mechanisms underlying the impacts of ocean acidification and warming on bivalve shell formation
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