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The transformation of aragonite to calcite in the presence of magnesium: Implications for marine diagenesis

Year: 2021
Products: prepFAST
Authors: Hashim, M;Kaczmarek, S;
Application: seawater;

Magnesium (Mg) in natural waters plays a critical role in governing carbonate mineral formation, dissolution, and diagenesis. Previous laboratory experiments show that Mg can strongly inhibit direct calcite precipitation as well as aragonite to calcite diagenetic transformation. Data from natural settings, however, suggest that diagenetic calcite in most Phanerozoic limestones has formed in the shallow marine burial realm in the presence of ample Mg. Thus, the diagenetic conditions under which aragonite-rich sediments convert to calcite-rich limestones are poorly understood. Here, we present data from laboratory experiments whereby aragonite is converted to calcite at 70 °C in Mg-bearing solutions to investigate the effects of fluid:solid ratio (F:S), which varies greatly across diagenetic environments, on Mg inhibition and incorporation in calcite. Our data show that not only can the transformation of aragonite to calcite occur in solutions with higher [Mg] than previously shown possible in laboratory experiments, but that progressively lower F:S increase the rate at which aragonite stabilizes to calcite. For example, in experiments with an F:S of 0.3 mL/g, which corresponds to sediments in a closed system with 50% porosity, aragonite stabilizes to calcite in solution with [Mg] =  30 mM (Mg/Ca =  5.14) when an initial high degree of undersaturation with respect to aragonite is used and in a solution with [Mg] =  20 (Mg/Ca =  5.14) when a low degree of undersaturation is used. In contrast, aragonite does not stabilize to calcite after nearly 3000 h in experiments with an F:S of 100 mL/g, which is more typical of an open system, even in a solution with [Mg] =  5 mM (Mg/Ca =  5.14) regardless of the degree of undersaturation. Our results also show that the amount of Mg incorporated into calcite products increases linearly with the increase of F:S. Collectively, these observations further point to F:S as an important factor in carbonate diagenesis with broad implications. First, the observations that transformation of aragonite to calcite is inhibited at high [Mg] and F:S imply that calcite precipitation is unlikely to occur in marine diagenetic environments that are in direct hydrologic contact with seawater. This leaves aragonite dissolution as the dominant diagenetic process in these environments, which may represent an underrated source of alkalinity to the open ocean. Second, transformation from aragonite-rich sediments to the calcite-rich limestones that dominate the rock record is likely promoted by a decrease in the F:S and the development of a closed system during progressive burial.

Zn elemental and isotopic features in sinking particles of the South China Sea: Implications for its sources and sinks

Year: 2021
Products: SC-Fast autosampler
Authors: Liao, W;Takano, S;Tian, H;Chen, H;Sohrin, Y;Ho, T;
Application: Total;

We determined the elemental and isotopic composition of Zn in sinking particles collected in the deep water of the northern South China Sea (NSCS) to investigate the relative contribution of various sources and assess their isotopic signatures. Using differentiable elemental ratios and δ66Zn of the potential sources, a mass balance approach estimates that anthropogenic aerosol Zn accounted for 64 ± 10% of the total Zn in sinking particles for more than 50% of the sampling period, indicating that anthropogenic aerosol Zn has become a dominant form of Zn source in the deep water. A relatively large discrepancy between the estimated and measured δ66Zn is observed during the high productivity season, which can be attributed to the elevated contribution of the biogenic hard parts or scavenging Zn on organic materials. Elevated δ66Zn values were observed at 3500 m during autumn which may be caused by the influence of authigenic particles during the lowest flux period. We found that the averaged measured output δ66Zn value, +0.35 ± 0.12‰, is significantly lighter than most of the output values proposed in previous studies. Due to recent findings highlighting the importance of anthropogenic aerosol Zn in the ocean, we have re-evaluated the solubility and fluxes of aerosol Zn in the ocean and found that the flux has been significantly underestimated in previous studies. The updated global aerosol Zn input to the ocean, ranging from 0.3 to 3.0 Gmol yr−1, is comparable to the output magnitude from hydrothermal and riverine sources. The updated Zn residence time would then be down to 1400 years on average. In addition to organic decomposition, the sinking particle data indicate that particle-associated removal and release processes play important roles in controlling Zn cycling in the water column. How anthropogenic aerosol deposition influences Zn fluxes and cycling in other oceanic regions deserves further investigation.

Potassium elemental and isotope constraints on the formation of tektites and element loss during impacts

Year: 2021
Products: Apex Omega desolvating unit
Authors: Magna, T;Jiang, Y;Skála, R;Wang, K;Sossi, P;Žák, K;
Application: Species;isotope;

Potassium elemental and isotope systematics were investigated for a suite of central European tektites from three strewn sub-fields in Czech Republic and possible parent sedimentary materials from the vicinity of the Ries impact structure in SE Germany, supplemented by data for several other impact-related materials (bediasites, Ivory Coast tektites, Libyan Desert Glass). This is paralleled by computation of potential K loss and attendant isotope fractionation for physico-chemical conditions typical for formation of tektite precursor melts. These theoretical calculations indicate a

Lack of redox cycling for nickel in the water column of the Eastern tropical north pacific oxygen deficient zone: Insight from dissolved and particulate nickel isotopes

Year: 2021
Products: SeaFAST preconcentration system
Authors: Yang, S;Kelly, R;Bian, X;Conway, T;Huang, K;Ho, T;Neibauer, J;Keil, R;Moffett, J;John, S;
Application: Biological;Dissolved;

Marine oxygen deficient zones (ODZs) promote unique plankton communities and redox environments which impact the cycling of biologically essential trace metals in the ocean. Here we use measurements of dissolved and particulate Ni concentrations and isotopes to investigate the biotic and abiotic processes controlling Ni cycling in the world’s largest ODZ, located in the Eastern Tropical North Pacific (ETNP). We observed a negative correlation between dissolved Ni concentrations and isotopic composition (δ60Ni) throughout the water column, such that Ni concentrations increased from roughly 3 nmol kg−1 to 8 nmol kg−1 over the upper 1000 m, while δ60Ni values decreased by 0.2‰ from about +1.6‰ to +1.4‰. These vertical patterns are characteristic of both the subtropical North and South Pacific, and can be explained by a combination of physical mixing of water masses and biological uptake and export, either with all of the Ni being bioavailable or with separate bioavailable and non-bioavailable Ni pools. Although evidence for additional Ni cycling processes such as sulfide precipitation or Ni sorption/desorption through Fe/Mn redox chemistry have been observed in other ODZs and euxinic waters, we found no clear evidence for these in either the redoxcline or low oxygen waters of the ETNP. Indeed, the relationship between dissolved [Ni] and δ60Ni observed in the ETNP is similar to results reported elsewhere in the subtropical North and South Pacific, falling generally on a mixing line between a surface water endmember (dissolved [Ni] = 2 nmol kg−1 and δ60Ni = +1.7‰) and a deep-water endmember (dissolved [Ni] = 6-10 nmol kg−1 and δ60Ni = ~+1.4‰). While this surface water endmember is similar to that of the Atlantic, the deep endmember in the Pacific is approximately 0.1‰ heavier than deep Atlantic Ni. This subtle isotopic difference suggests gradual accumulation of isotopically heavy Ni isotopes in the deep ocean, consistent with recent evidence of heavy Ni remobilization during early diagenesis. Lastly, in the ETNP, particulate δ60Ni is generally ~0.5‰ lighter than the dissolved Ni pool, and this pattern is consistent across both the euphotic zone and redoxcline, suggesting that biological export from the euphotic zone is the primary source of particulate Ni to the deep ocean.

Temporally and spatially dynamic redox conditions on an upwelling margin: The impact on coupled sedimentary Mo and U isotope systematics, and implications for the Mo-U paleoredox proxy

Year: 2021
Products: in-house Elemental Scientific ICPMS (CPI) standard
Authors: He, Z;Clarkson, M;Andersen, M;Archer, C;Sweere, T;Kraal, P;Guthauser, A;Huang, F;Vance, D;
Application: seawater;isotope;

The abundances and isotope compositions of molybdenum (Mo) and uranium (U) in ancient sediments are promising tracers of the redox state of the past ocean, whose basis lies in the environmentally dependent Mo and U isotope signatures in modern oceanic settings. Despite their dominance in oceanic budgets, the controls on the Mo-U systematics of upwelling margin sediments remain to be fully understood. Here we present a comprehensive sediment-porewater Mo and U isotope study in the Benguela upwelling system off Namibia, including the first dataset incorporating coupled Mo-U abundance and isotope analysis of both solid authigenic phases and porewaters. The investigated stations represent shelf-to-slope settings, which lie on the upper edge, within and below the oxygen minimum zone (OMZ) of the South Atlantic. The sediments across all stations share similar characteristics: both Mo and U show increasing authigenic enrichment with depth, coupled to an overall decrease in δ98Moauth (from ~2.0‰ to 1.3‰ and from ~2.0‰ to 0.3‰) and increase in δ238Uauth (from −0.18‰ to 0.05‰ and from −0.34‰ to −0.21‰). Nevertheless, the extents of Mo and U enrichment and associated isotopic fractionations display spatial variability across the OMZ, reflecting variations in local sedimentary redox conditions. Porewater Mo and U concentration patterns are more complex, exhibiting peaks in Mo and U abundance well in excess of seawater (up to 8 times seawater for Mo) associated with correlated shifts in isotope composition. As a result, porewaters exhibit a wide range in isotope compositions, between 0.90‰ and 2.79‰ for δ98Mo and between −1.74‰ and 0.26‰ for δ238U. Porewater gradients at the time of sampling are inconsistent with diffusion downwards across the sediment-seawater interface as a means of enrichment of the sediment-porewater system. Though these sampled conditions may represent only a snapshot, so that periodically more reducing conditions could lead to concentration gradients that do permit downward diffusion, the data are also readily explained by addition of Mo and U to the sediment-porewater system in particulate form, also under more reducing conditions than at the time of sampling. For example, sequestration of Mo and U to particulate matter as a result of the presence of intermittent sulfide, either in bottom water or in porewater right at the sediment-water interface, explains much of the geochemical and isotope data. The data thus suggest that the early diagenetic enrichment of Mo and U in sediments of upwelling margins is strongly governed by temporal redox fluctuations. Early diagenesis under these dynamic redox conditions on the Namibian upwelling margin are strongly reflected in Mo-U co-variation patterns, as well as anti-correlations between authigenic δ98Mo and δ238U in sediments. Overall, our new data demonstrate that early diagenetic processes on open-marine continental margins reproduce patterns previously observed for coupled Mo-U isotope systematics in restricted and semi-restricted basins, but via a different set of processes and with important implications for the use of such a coupled approach in the study of ancient marine anoxia.

Inhalation of tungsten metal particulates alters the lung and bone microenvironments following acute exposure

Year: 2021
Products: SeaFast
Authors: Miller, K;McVeigh, CM;Barr, EB;Herbert, GW;Jacquez, Q;Hunter, R;Medina, S;Lucas, SN;Ali, AS;Campen, MJ;Bolt, AM;
Application: Tissue;

Inhalation of tungsten particulates is a relevant route of exposure in occupational and military settings. Exposure to tungsten alloys is associated with increased incidence of lung pathologies, including interstitial lung disease and cancer. We have demonstrated, oral exposure to soluble tungsten enhances breast cancer metastasis to the lungs through changes in the surrounding microenvironment. However, more research is required to investigate if changes in the lung microenvironment, following tungsten particulate exposure, can drive tumorigenesis or metastasis to the lung niche. This study examined if inhalation to environmentally relevant concentrations of tungsten particulates caused acute damage to the microenvironment in the lungs and/or systemically using a whole-body inhalation system. Twenty-four female BALB/c mice were exposed to Filtered Air, 0.60 mg/m3, or 1.7 mg/m3 tungsten particulates (< 1 µm) for 4 h. Tissue samples were collected at day 1 and 7 post-exposure. Tungsten accumulation in the lungs persisted up to 7 days post-exposure and produced acute changes to the lung microenvironment including increased macrophage and neutrophil infiltration, increased levels of pro-inflammatory cytokines IL-1β and CXCL1, and an increased percentage of activated fibroblasts (α-SMA+). Exposure to tungsten also resulted in systemic effects on the bone, including tungsten deposition and transient increases in gene expression of pro-inflammatory cytokines. Taken together, acute whole-body inhalation of tungsten particulates, at levels commonly observed in occupational and military settings, resulted in changes to the lung and bone microenvironments that may promote tumorigenesis or metastasis and be important molecular drivers of other tungsten-associated lung pathologies such as interstitial lung disease.

Precambrian paleosols on the Great Unconformity of the East European Craton: An 800 million year record of Baltica’s climatic conditions

Year: 2021
Products: Elemental Scientific Lasers NWR193UC laser ablation system
Authors: Liivamägi, S;Środoń, J;Bojanowski, M;Stanek, J;Roberts, N;
Application: Laser;

Meso- and Neoproterozoic paleosols, collected from different areas of the East European Craton: Belarus, Estonia, Lithuania, and Ukraine, offer a chance to examine continental weathering sequences from early to advanced stages of weathering on a variety of different parent materials such as gneisses, granites, gabbros and amphibolites. They were studied using quantitative XRD of the bulk rock, XRD and Mössbauer of the clay fractions, microscopic, geochemical, carbonate stable isotopes and carbonate U-Pb geochronology methods. These paleosol profiles are on average 10 m thick, reddish coloured, and many of them are characterized by a well-developed and well-defined alteration sequence with uppermost horizons approaching the lateritic stage, as indicated by the Chemical Index of Alteration values reaching 90. The dominant type of weathering leads towards kaolinite and a Fe-oxide/hydroxide mineral assemblage through a smectitic intermediate stage. In the paleosol profiles developed on mafic parent materials, dioctahedral smectite is the first weathering product at the base, it dominates in the middle-upper horizons and it later becomes unstable and alters into kaolinite; whereas in paleosols developed on felsic parent materials kaolinite forms already at the initial stage of weathering, as a result of Na-plagioclase dissolution. Kaolinite content in the uppermost horizons reaches 34 wt% in the best developed profile, and Fe-minerals (hematite and goethite) show a clear increasing trend towards the top, reaching 12 wt%. It is likely that uppermost kaolinite-dominated horizons, which are lacking in some profiles, have been eroded. Such paleosol composition and ferric composition of smectites indicate oxidative weathering and are interpreted to represent a warm and humid climate, which seems to have prevailed on the EEC over the Meso- and Neoproterozoic, except well-documented glacial periods. The δ13C signatures of the pedogenic carbonates document microbial processes in the paleosols, which is also indicated by the elevated U/Th values in their top layers. One paleosol was dated with in situ pedogenic calcite U-Pb geochronology at 655 ± 45 Ma (2σ), confirming the estimate based on its stratigraphic position. The Proterozoic paleosol profiles, and dioctahedral smectite in particular, remained unaltered for over 900 Ma until the Paleozoic, when they were affected by low-temperature (

Concomitant oral intake of purified clinoptilolite tuff (G-PUR) reduces enteral lead uptake in healthy humans

Year: 2021
Products: ESI SC-2 DX FAST autosampler
Authors: Samekova, K;Firbas, C;Irrgeher, J;Opper, C;Prohaska, T;Retzmann, A;Tschegg, C;Meisslitzer, C;Tchaikovsky, A;Gouya, G;Freissmuth, M;Wolzt, M;
Application: Urine;Blood;Total;isotope;

Lead exposure can cause substantial organ damage. Enteral lead absorption may be reduced by concomitant intake of clinoptilolite tuff, a zeolite from natural sources. This study aimed to assess the effect of purified clinoptilolite tuff (G-PUR) on enteral lead uptake in adults using stable lead isotope 204Pb as a tracer. In this randomized, placebo-controlled, double-blind, parallel-group study, 42 healthy participants were randomized to receive oral G-PUR 2.0 g, 2 * 2.0 g, or placebo, together with 2.5 µg of 204Pb in water. The enrichment of 204Pb caused by the tracer in blood and urine was measured by mass spectrometry. G-PUR was well tolerated. The mean maximum 204Pb enrichment of 0.505% of total blood lead was significantly higher (p < 0.0001) in the placebo group compared to G-PUR 2.0 g (0.073%) or G-PUR 2 * 2.0 g (0.057%) group. Normalized 204Pb AUC0-192 was 86.5, 11.9, and 8.5% * h without and with G-PUR 2.0 g, and G-PUR 2 * 2.0 g, respectively (p < 0.0001 vs. placebo). This smaller 204Pb exposure was paralleled by a reduced urinary excretion in subjects receiving G-PUR. Concomitant oral intake of purified clinoptilolite tuff reduced enteral uptake of 204Pb in healthy humans by approximately 90%. The reduced bioavailability is demonstrable by a decrease of 204Pb tracer enrichment in blood and urine.Trial registration: identifier: NCT04138693, registered 24/10/2019.

Histopathological effects of short-term aqueous exposure to environmentally relevant concentration of lead (Pb) in shorthorn sculpin (Myoxocephalus scorpius) under laboratory conditions

Year: 2021
Products: prepFAST
Authors: Jantawongsri, K;Nørregaard, RD;Bach, L;Dietz, R;Sonne, C;Jørgensen, K;Lierhagen, S;Ciesielski, TM;Jenssen, BM;Haddy, J;Eriksen, R;Nowak, B;
Application: Blood;Cells;Environmental;Dissolved;Species;

Shorthorn sculpin (Myoxocephalus scorpius) has been used as a sentinel species for environmental monitoring, including heavy metal contamination from mining activities. Former lead-zinc (Pb-Zn) mines in Greenland resulted in elevated concentrations of metals, especially Pb, in marine biota. However, the potential accumulation of Pb and effects of the presence of Pb residues in fish on health of sculpins observed in the field have not been validated in laboratory experiments. Therefore, our aim was to validate field observation of shorthorn sculpin via controlled laboratory exposure to environmentally relevant concentrations of dissolved Pb. We evaluated the effects of a short-term (28 days) exposure to Pb on Pb residues in sculpin blood, gills, liver, and muscle and the morphology of gills and liver. The highest level of Pb was found in the gills, followed by muscle and then liver. Pb levels in liver, gills, and blood of Pb-exposed sculpins were significantly higher than those in control fish, showing that blood is suitable for assessing Pb accumulation and exposure in sculpins. Histopathological investigations showed that the severity score of liver necrosis and gill telangiectasia of Pb-exposed sculpins was significantly greater than in control fish. The number of mucous cells in gills was positively correlated with Pb concentrations in organs. Overall, the results validated field observation for the effects of Pb on wild sculpin and contributed to the improved use of the shorthorn sculpin as sentinel species for monitoring contamination from Pb mines in the Arctic.

Evaluating a Modified High Purity Polysorbate 20 Designed to Reduce the Risk of Free Fatty Acid Particle Formation

Year: 2021
Products: PC3 Peltier-cooled spray chamber and a microflow nebulizer
Authors: Doshi, N;Ritchie, K;Shobha, T;Giddings, J;Gregoritza, K;Taing, R;Rumbelow, S;Chu, J;Tomlinson, A;Kannan, A;Saggu, M;Cai, SK;Nicoulin, V;Liu, W;Russell, S;Luis, L;Yadav, S;
Application: Species;Drug;

To evaluate a modified high purity polysorbate 20 (RO HP PS20)-with lower levels of stearate, palmitate and myristate esters than the non-modified HP PS20-as a surfactant in biopharmaceutical drug products (DP). RO HP PS20 was designed to provide functional equivalence as a surfactant while delaying the onset of free fatty acid (FFA) particle formation upon hydrolytic degradation relative to HP PS20.Analytical characterization of RO HP PS20 raw material included fatty acid ester (FAE) distribution, higher order ester (HOE) fraction, FFA levels and trace metals. Functional assessments included 1) vial and intravenous bag agitation; 2) oxidation via a placebo and methionine surrogate study; and 3) hydrolytic PS20 degradation studies to evaluate FFA particle formation with and without metal nucleation.Interfacial protection and oxidation propensity were comparable between the two polysorbates. Upon hydrolytic degradation, FFA particle onset was delayed in RO HP PS20. The delay was more pronounced when HOEs of PS20 were preferentially degraded. Furthermore, the hydrolytic degradants of RO HP PS20 formed fewer particles in the presence of spiked aluminum.This work highlights the criticality of having tighter control on long chain FAE levels of PS20 to reduce the occurrence of FFA particle formation upon hydrolytic degradation and lower the variability in its onset. By simultaneously meeting compendial PS20 specifications while narrowing the allowable range for each FAE and shifting its composition towards the shorter carbon chain species, RO HP PS20 provides a promising alternative to HP PS20 for biopharmaceutical DPs.

Assessing the reproducibility of labelled antibody binding in quantitative multiplexed immuno-mass spectrometry imaging

Year: 2021
Products: laser ablation system
Authors: Mello, MG;Westerhausen, MT;Singh, P;Doble, PA;Wanagat, J;Bishop, DP;
Application: Biological;Tissue;Laser;

Immuno-mass spectrometry imaging (iMSI) uses laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to determine the spatial expression of biomolecules in tissue sections following immunolabelling with antibodies conjugated to a metal reporter. As with all immunolabelling techniques, the binding efficiency of multiplexed staining can be affected by a number of factors including epitope blocking and other forms of steric hindrance. To date, the effects on the binding of metal-conjugated antibodies to their epitopes in a multiplexed analysis have yet to be quantitatively explored by iMSI. Here we describe a protocol to investigate the effects of multiplexing on reproducible binding using the muscle proteins, dystrophin, sarcospan, and myosin as a model, with antibodies conjugated with Maxpar reagents before histological application to murine quadriceps sections using standard immunolabelling protocols and imaging with LA-ICP-MS. The antibodies were each individually applied to eight sections, and multiplexed to another eight sections. The average concentrations of the lanthanide analytes were determined, before statistical analyses found there was no significant difference between the individual and multiplexed application of the antibodies. These analyses provide a framework for ensuring reproducibility of antibody binding during multiplexed iMSI, which will allow quantitative exploration of protein-protein interactions and provide a greater understanding of fundamental biological processes during healthy and diseased states.

Potassium isotopic composition of 7 widely available biological standards using collision cell (CC)-MC-ICP-MS.

Year: 2021
Products: 100 μL/min PFA nebulizer
Authors: Moynier, F;Hu, Y;Dai, W;Mahan, B;MOUREAU, J;
Application: Biological;isotope;geochemistry;

The development of collision-cell multi-collection inductively-coupled-plasma mass-spectrometers has revolutionized K isotope geochemistry, improving the sensitivity by over a factor 10 compared to older generation instruments. The application of isotope geochemistry...

Application of multi-isotope calibration to analysis of wine samples by ICP-MS

Year: 2021
Products: 500 µL sample loop
Authors: Wheal, M;Wilkes, E;
Application: isotope;

Analysis for trace (Cu, Fe, Sr, Zn) and ultra-trace (Cr, Ni, Pb, Sn) elements in table wines using the multi-isotope calibration technique was closely correlated with results measured by conventional external calibration with internal standards.

Direct analysis of cotton swipes for plutonium isotope determination by microextraction-ICP-MS

Year: 2021
Products: high sensitivity skimmer cone (X)
Authors: Manard, B;Metzger, S;Rogers, K;Ticknor, B;Zirakparvar, N;Roach, B;Bostick, D;Hexel, C;
Application: isotope;

This study demonstrates a method for determining the isotopic composition of low-level (sub-pg) plutonium (Pu) directly from a cotton swipe.

Further characterization of SA01 and SA02 zircon reference materials for Si and Zr isotopic compositions via femtosecond laser ablation MC-ICP-MS

Year: 2021
Products: 257 nm NWRFemto fs-LA
Authors: Huang, C;Wang, H;Yu, H;Feng, L;Xie, L;Yang, Y;Wu, S;Xu, L;Yang, J;
Application: Laser;

We present Si and Zr isotopic data of SA01 and SA02 zircons via multi-technique analytical methods to evaluate the suitability of the two zircon reference materials for in situ Si and Zr isotopic analysis using fs-LA-MC-ICP-MS.

Calcium isotope values of modern and fossil cephalopod shells - Trophic level or proxy for seawater geochemistry?

Year: 2021
Products: prepFAST
Authors: Hoffmann, R;Riechelmann, S;Liebetrau, V;Eisenhauer, A;Immenhauser, A;
Application: Dissolved;Species;seawater;isotope;geochemistry;

Carbonate hardparts of marine organisms are frequently explored archives of their ambient seawater composition. Among the various materials used, the hardparts of molluscs are particularly relevant because their accretionary growth allows for the compilation of time-resolved proxy data sets. Here, we explore to which extent the calcium isotope values of aragonitic cephalopod hardparts represent proxies for seawater composition or record a trophic level signal. In a first step, we collect Ca isotope data from a diverse set of modern cephalopods, including Nautilus, Sepia and Spirula. These taxa differ in their external/internal hardparts, life spans, trophic levels, habitat depth, hinterland geology, and resulting runoff. In a second step, we have put these concepts to the test and explore the calcium isotope signatures of Lower Cretaceous (lower Albian) well-preserved cephalopods (nautiloids, ammonoids and belemnites) and bivalve shells from Madagascar. In the sense of a methodological comparison, two measurement approaches (double spike (δ44/40Ca, TIMS) and bracketing standard (δ44/42Ca, MC-ICP-MS) techniques are applied. Calcium from organic matter and intra-shell variations on bulk δ44/40Ca isotope values are explored. Four protocols (H2O2, NaOH, HClO4, incineration up to 250 °C including subsequent rinsing with deionised water and Ca removal) are applied to destroy organic matter in the shell material and to dissolve any non‑carbonate bound Ca, i.e., its metastable secondary Ca reservoir. These are equally successful, and the Ca isotope values of the purified carbonate phase plot on the equilibrium mass fractionation line. Samples not treated to destroy or remove their organic matter do not fall on the equilibrium mass fractionation line. Limitations of sample pre-treatment are reflected by a slight shift towards lower values in the case of incineration experiments at 650 °C. This feature is best explained in the context of a mineralogical phase transformation of aragonite to calcite. Calcium isotope values show no significant variability when sampling hardparts with different microstructures (callus, nacre, prismatic layer) and mineralised during different ontogenetic phases (outer shell, septa). Perhaps most relevant, mean δ44/40Ca (‰ SRM-915a) isotope values for Nautilus (0.72‰ ±0.19 2SD), Sepia (0.79‰ ±0.18 2SD), and Spirula (0.50‰ ±0.18 2SD) lack evidence for a significant control by trophic levels. Nitrogen isotope data and known diets for all three cephalopods serve as a litmus test for these data, which do not correlate with this dietary proxy information. These results are considered encouraging and suggest that Ca isotope values of cephalopod shells are proxies for their ambient seawater Ca isotope signatures. According to our data, however, it remains unclear to which extend cephalopod hardparts record the Ca isotopic composition of past seawater. Specifically, the data from three different modern species point to a mean Δ44/40Ca(ceph-seawater) fractionation of −1.21‰ (± 0.15 2SD). Based on our work, we present a best practice guide for cephalopod Ca isotope analysis and interpretation.

Geochronology, geochemistry and Sr-Nd-Hf isotopes of the Heihuashan granite porphyry, NE China, and implications for Cu-Mo mineralization

Year: 2021
Products: NWR 193 UC laser ablation system
Authors: Li, L;Shu, Q;Xing, K;Zhao, Z;Niu, X;
Application: Laser;geochemistry;

Heihuashan is a newly discovered porphyry Cu-Mo prospect in Heilongjiang Province, northeastern China, with considerable Cu and Mo mineralization. Until now the ages of the Cu-Mo ores and the causative granite porphyry, the magma origin and characteristics, as well as the mineralization potential at depth are still unclear. In this contribution, whole rock geochemical and Sr-Nd isotopic compositions, zircon U-Pb ages and Hf isotopes, and molybdenite Re-Os dating, are presented to constrain the timing of the magmatism and mineralization, and the petrogenesis of the causative intrusion. The results also provide an opportunity for evaluating the potential of the deep Cu-Mo mineralization. Zircon U-Pb dating using LA-ICP-MS yields a crystallization age of 146.4 ± 1.8 Ma for the Heihuashan granite porphyry, which is consistent with the molybdenite Re-Os isochron age of 143.7 ± 3.1 Ma. These results indicate that the porphyry Cu-Mo mineralization at Heihuashan occurred at late Jurassic to early Cretaceous. The whole rock geochemical data suggest that the ore-related intrusion is mildly peraluminous and belongs to the high-K calc-alkaline series, I-type granitoids. The granite porphyry samples are enriched in Rb, Ba, Th, U, and Sr, but depleted in Nb and Ta, showing typical arc magma affinities. They also have initial 87Sr/86Sr ratios of 0.70546-0.70550 and εNd(t) values between +0.4 and +0.7. The zircon εHf(t) values for the granitic intrusion range from +3.5 to +9.2, with two-stage Hf model ages of 977-614 Ma. The geochemical and Sr-Nd-Hf isotopic compositions suggest that the parental magma was dominantly derived from the slab-metasomatized mantle, which could have mixed with some lower crust components. The Fe2O3/FeO ratios of the Heihuashan granite porphyry are relatively high, ranging from 0.52 to 1.17, indicating a high magmatic oxidation state. This is also supported by the high zircon Ce/Ce*, Eu/Eu* and Ce/Nd ratios (33-2433, 0.22-0.70 and 2.4-44.0, respectively) and the high magmatic ΔFMQ values (+0.1 to +3.5 with an average of +2.1) calculated using the zircon trace elements. The intrusion has relatively high Sr/Y ratios (40-94) and displays negligible Eu anomalies (Eu/Eu* = 0.68-1.07); the zircons from the intrusion have high (Eu/Eu*)/Y (mostly > 0.0001) and (Ce/Nd)/Y ratios (mostly > 0.01), but low Dy/Yb ratios (generally < 0.4). These suggest that the fractionation of hornblende rather than plagioclase is dominant during the magma crystallization, which reveals a high magmatic water content. The above results indicate that the ore-related magma at Heihuashan is oxidized and hydrous, both of which are critical for porphyry Cu-Mo mineralization. The Heihuashan granite porphyry is geochemically similar to other Cu-related intrusions in NE China and also comparable to many porphyry Cu (-Mo) systems worldwide, implying a high Cu-Mo mineralization potential. Considering the surface and shallow levels at Heihuashan are characterized dominantly by sericite alteration, we suggest exploration and drilling focusing on the deeper levels beneath the currently mineralized domains, where major potassic alteration zones, likely associated with more extensive Cu-Mo mineralization, could be discovered.

Assessing the utility of barium isotopes to trace Eurasian riverine freshwater inputs to the Arctic Ocean

Year: 2021
Products: prepFAST
Authors: Bridgestock, L;Nathan, J;Hsieh, Y;Holdship, P;Porcelli, D;Andersson, P;Henderson, G;
Application: Dissolved;seawater;isotope;

Tracing riverine freshwater transport pathways within the Arctic Ocean is key to understanding changes in Arctic Ocean freshwater inventories. Dissolved Ba concentrations have been used in this capacity but are compromised by non-conservative processes. To assess the potential for Ba isotopes to provide insights into the impact of such processes on Arctic Ocean dissolved Ba inventories, Ba concentration and isotope data for surface seawater samples from the Siberian Shelf and Bering Sea/Strait are presented. These samples capture the mixing of riverine freshwater discharged by the rivers Yenisey, Lena and Ob, with Atlantic and Pacific derived seawater, which are traced by relationships between salinity, Ba concentration and δ138/134Ba. The δ138/134Ba of net river inputs, following modification by estuarine processes, are constrained to be 0.31 ± 0.04‰, 0.20 ± 0.06‰ and 0.23 ± 0.04‰, for the rivers Yenisey, Lena and Ob respectively. These values are used to estimate an average δ138/134Ba for Eurasian river freshwater input to the Arctic Ocean of 0.23 ± 0.04‰. The Ba concentration and δ138/134Ba of Lena River freshwater transported across the Laptev Sea are modified by non-conservative processes. These non-conservative processes do not result in distinctive modification of dissolved Ba concentration-δ138/134Ba mixing relationships between Eurasian riverine freshwater and Arctic seawater, which unfortunately limits the potential of Ba isotopes to improve tracing riverine freshwater sources in the central Arctic Ocean basins using dissolved Ba inventories. More generally the results of this study help advance understanding of Ba isotope cycling in the environment and their development as an emerging tracer of marine processes.

New prospects to the multi-elemental analysis of single microcrystal of apatite by total-reflection X-ray fluorescence spectrometry

Year: 2021
Products: NWR213 laser ablation attachment
Authors: Maltsev, A;Ivanov, A;Pashkova, G;Marfin, A;Bishaev, Y;
Application: Environmental;Total;Laser;

The elemental analysis of apatite minerals is an important study that is utilized in several applications in geology, biology, medicine, agriculture, technology, and environmental remediation. Laser ablation inductively coupled mass spectrometry (LA-ICP-MS) is a routine method for the elemental analysis of apatite microcrystals in geological applications. In this study, we propose a new method for the analysis of single grain of apatite with a mass of a few μg using total-reflection X-ray fluorescence spectrometry (TXRF), which is faster, cheaper, and easier in quantification procedure than LA-ICP-MS. The direct preparation of the single apatite microcrystal on the quartz carrier using nitric acid digestion and quantification using the stoichiometric value of P as an internal standard allows to obtain the major, minor, and trace elements (from K to U) simultaneously. For the choice of the internal standard in TXRF, the Raman spectroscopy is applied to obtain the information of the mineral phases and their distribution formed in the apatite sample after the digestion procedure. Validation of the proposed TXRF method is conducted by the analysis of reference materials (Durango and Otter Lake) and comparison of results with the TXRF for bulk-type of apatite and LA-ICP-MS methods.

Rapid determination of ultra-trace plutonium in large volume of urine samples by tandem quadrupole inductively coupled plasma-mass spectrometry

Year: 2021
Products: APEX-Ω
Authors: Wu, Y;Xu, Y;Xing, S;Dai, X;Yuan, N;Luo, M;
Application: Urine;nuclear;detection limits;

Rapid bioassay method for plutonium in urine samples are employed to assess the possible internal dose resulting from exposure to plutonium in the event of a radiological and nuclear emergency. In this work, a rapid method for the determination of plutonium isotopes (239Pu and 240Pu) in large volume of urine samples was developed using tandem quadrupole ICP-MS combined with a high-efficiency sample introduction system (APEX-Ω). The mixture gases of NH3 and He was employed to effectively eliminate the tailing of 238U and the uranium hydride ions (238U1H+and 238U1H2+) and significantly improve the measurement sensitivity of plutonium. The method was validated by analyzing urine samples spiked with known amounts of 239Pu and 240Pu ranging from 1 to 60 fg. The detection limits for the method were estimated to be 0.83 fg for 239Pu, 0.14 fg for 240Pu in 1 L of urine.

Serum and Hair Trace Element and Mineral Levels in Dairy Cows in Relation to Daily Milk Yield

Year: 2021
Products: ESI SC-2 DX4 autosampler
Authors: Sizova, EA;Miroshnikov, SA;Notova, SV;Marshinskaya, OV;Kazakova, TV;Tinkov, AA;Skalny, AV;
Application: Serum;Total;

The objective of the present study was to assess hair and serum trace element and mineral levels in dairy cows in relation to daily milk yield. A total of 70 healthy 5-6-year-old Simmental cows were divided into two groups (n = 35) with high and low daily milk yield using median as a cut-off value. Hair and serum trace element and mineral content was evaluated using inductively coupled plasma mass-spectrometry. A nearly twofold difference in daily milk yield (43.8 ± 9.7 vs 21.3 ± 7.1 L/day, p < 0.001) was significantly associated with 11% lower hair Cu (p = 0.043) and 35% higher Se levels (p = 0.058) content when compared animals with lower daily milk yield. Serum trace element levels were found to be more tightly associated with milk productivity in dairy cows. Particularly, serum levels of Se and Zn were found to be 73 and 35% higher in cows with higher milk productivity in comparison to animals with lower milk production, respectively. Serum Co levels also tended to increase with higher milk productivity. Serum minerals including Ca, Mg, and P were also found to be higher in highly productive cows by 6%, 14%, and 71%, respectively. The overall regression model based on serum trace element and mineral levels accounted for 38% of daily milk production variability. Generally, improvement of essential trace element and mineral supply, as well as prevention of copper overload in dairy cows, may be considered the potential tool for modulation of milk productivity.

Source-to-sink transformation processes between closed setting, semiopen setting, and opening setting: A case study of the West-East China Sea from the Paleocene to the Eocene

Year: 2021
Products: NWR193UC 193-nm deep-ultraviolet laser ablation sampling system
Authors: Fu, C;Li, S;Li, S;Xu, J;
Application: Laser;

For complex convergence movements between the Pacific Plate and Eurasian Plate since the Cenozoic, the East China Sea Basin (ECSB) presents a three-stage rifting movement: initial rifting, rifting development, and structural reversal stages. The ECSB changed from a closed lacustrine to an open marine source-to-sink (S2S) system and then returned to a semiopen bay S2S system. Recently, research has attracted more attention to the relationship between the depositional setting evolution and the corresponding source-to-sink patterns. This study determines that the early Paleocene was dominated by a closed lacustrine setting according to water salinities based on trace element and micropalaeontological assemblages. The middle Paleocene had an open marine setting, and the late Paleocene and Eocene had semiopen bay settings. In addition, we rebuild the provenance area of the S2S system with detrital zircon Usingle bondPb data and heavy mineral assemblage data to interpret the provenance from seismic profiles. During the early Paleocene, proximal sediments dominated the western depression zone of the East China Sea (WDZ), which was isolated by three sags. Integrated from core, well logging, and grain size data, the sediments in the routing system migrated to the prograding delta or alluvial fan. With statistics of the S2S parameters on the early Paleocene strata, sediment supply, average terrain height, and volume of the S2S system are analyzed from a bubble chart, which indicates that the average terrain height had a positive correlation with the S2S volume. For the middle Paleocene, more sediments from the Zhe-Min Caledonian fault belts on the western side distally migrated to the drainage basin and were deposited as tidally dominated deltas, reflecting an increasing reworking process. The statistical results show that the sediment supply was a dominant factor in the S2S system. As the regression proceeded, the S2S system developed in a semiopen bay setting in the late Paleocene and Eocene. A wave-dominated delta existed on the western side of the WDZ, and the eastern side developed subaqueous deltas. Moreover, we note that the sediment supply and average terrain height were important factors in developing the S2S system.

Seawater‐Particle Interactions of Rare Earth Elements and Neodymium Isotopes in the Deep Central Arctic Ocean

Year: 2021
Products: seaFAST
Authors: Paffrath, R;Pahnke, K;Böning, P;Rutgers van der Loeff, M;Valk, O;Gdaniec, S;Planquette, H;
Application: Total;seawater;

One aspect that may explain the different behavior of particles in the Arctic Ocean compared to other ocean basins may be the relative importance of authigenic and lithogenic associated REEs. The relative proportions of authigenic and lithogenic REEs can be calculated using particulate 232Th or Al concentrations, as presented, for example, in Garcia-Solsona et al. (2014) and Tachikawa et al. (1997) with continental crust concentrations from Rudnick and Gao (2003). Particulate 232Th and Al serve as conservative tracers of the lithogenic fraction. If available, 232Th is preferred to Al as Al can also have a non-crustal source (Dymond et al., 1997). The 232Th-based calculated lithogenic fractions exceeding 100% only at station 50 could also be due to an excess of 232Th in the particles caused by 232Th in the authigenic fraction (Hayes et al., 2015; Lagarde et al., 2020), but the effect is smaller for 232Th than for Al. Therefore, we used particulate 232Th concentrations from Valk et al. (2018) and Gdaniec et al. (2020) (same cruise as this study) for the calculation of the lithogenic REE fraction. At most stations, the lithogenic [Nd] are constant throughout the water column (Figure 7a), whereas the authigenic fractions show a larger range from 0 to 3.5 pmol/kg pNd (see Paffrath et al., 2021b). The relative contribution of lithogenic and authigenic fractions to the total particulate concentration (presented as % lithogenic, Figure 7b) show a dominance (≥50%) of the lithogenic fraction at most stations except a few samples from stations 50 and 125. The lack of any trends with water depth in the authigenic fraction are a result of the total [pNd] that vary with depth without showing systematic trends. In contrast to what is observed in the Arctic Ocean, most open-ocean settings show a dominance of biogenic/authigenic material in the particle composition (Lam & Marchal, 2015 and references therein), while for areas closer to the margins or with dust deposition, the lithogenic material can be the dominant contributor to the particle composition (Lam et al., 2015). Specifically for pREEs, authigenic particles dominate most stations in the Southeast Atlantic (Garcia-Solsona et al., 2014), whereas a dominance of the authigenic or lithogenic fraction is hard to determine in the Northeast Atlantic (Tachikawa et al., 1999) due to high errors in the calculated authigenic fraction (caused by the small difference between the measured total and the authigenic εNd). In the North Atlantic, the lithogenic fraction is especially high at the margins and decreases toward the open ocean (Lagarde et al., 2020). Model tests revealed that the authigenic Nd scavenged by particles is completely remineralized in the deep ocean (Tachikawa et al., 2003), whereas the influence of lithogenic sources, for example, dust is often restricted to the surface waters (e.g., Stichel et al., 2015). Different types of particles dissolve differently with depth and also show different scavenging behavior depending on the scavenged element (Siddall et al., 2008) and the scavenger (e.g., Schijf et al., 2015). [image] [/cms/asset/1fde6006-8f2c-4c79-b762-1853c5fd6862/jgrc24652-fig-0007-m.jpg]

Biogeochemical Cycling of Colloidal Trace Metals in the Arctic Cryosphere

Year: 2021
Products: SeaFAST
Authors: Jensen, L;Lanning, N;Marsay, C;Buck, C;Aguilar‐Islas, A;Rember, R;Landing, W;Sherrell, R;Fitzsimmons, J;
Application: Dissolved;seawater;isotope;

The Arctic Ocean is particularly vulnerable to climate change that results in increased freshwater inputs, such as river discharge and sea ice melt. This may also result in an increase or decrease in nutrient supply to the microorganisms living in the surface ocean who have metabolic requirements for survival. In fact, microorganisms need “trace” metals, found in very low abundances, that can be supplied by rivers and sea ice. However, the physical size of these metals may change how available they are to microorganisms. Here, we examine a size spectrum (∼0.003-0.200 μm) of important trace metals within snow, sea ice, melt ponds that form on sea ice, and the underlying seawater. These frozen reservoirs may serve as temporary “holding areas” for small trace metal particles to aggregate or dissolve, thus changing their availability or reactivity to microorganisms. Our goal was to assess what percentage of the overall sample is “small” (soluble

Middle Jurassic-Lower Cretaceous glendonites from the eastern Barents Shelf as a tool for paleoenvironmental and paleoclimatic reconstructions

Year: 2021
Products: PFA MicroFlow Nebulizer (50 l min − 1)
Authors: Mikhailova, K;Rogov, M;Ershova, V;Vereshchagin, O;Shurekova, O;Feodorova, A;Zakharov, V;
Application: seawater;

Glendonites are carbonate pseudomorphs after ikaite which use as indicators of near-freezing temperatures. We describe the first glendonites of Middle-Late Jurassic to Early Cretaceous age from the Barents Shelf, including the first glendonites of Late Barremian-Early Aptian age ever discovered on Earth and provide the detailed mineralogical-geochemical and isotopic studies. Mesozoic glendonites are well-known across the Arctic realm, however the ikaite-calcite transformation and implication of glendonite findings are still debatable. Pseudomorphs are mainly composed of calcite. Cathodoluminescence and scanning electron microscopy studies reveal three types (I-III) of calcite: type I - elongated, rounded and irregular calcite; type II - blocky, fibrous and needle-like calcite/siderite; type III - blocky calcite in pores. Elemental analyses distinguish geochemical differences between the calcite types: type I comprises pure CaCO3; type II calcite contains Mg and P (in all studied samples), Fe (Bajocian-Callovian), S (Middle Volgian) or Sr (Upper Barremian-Lower Aptian); type III calcite is depleted in Mg, P and Fe. Concentrations of Mn, Fe, Sr and calculated Mn/Ca, Fe/Ca and Sr/Ca ratios are suggestive of diagenetic alteration. Bulk δ18O values range from −5.39 to −1.71‰ VPDB, supporting overprinting of primary values during burial diagenesis, while bulk δ13C values range from −33.3 to −22.6‰ VPDB, providing the influence of organic matter on ikaite-glendonite formation. However, 87Sr/86Sr values range from 0.7070 to 0.7110, mainly corresponding to Jurassic-Cretaceous seawater. Rare-earth elements characterize porewater REE-patterns, with slight middle REE-enrichment and depletion in light and heavy REE. Weak positive and negative Ce anomalies indicate fluctiating from anoxic to oxic conditions during ikaite-glendonite formation. Our new biostratigraphic data refine the ages of glendonite-bearing horizons in the Barents Shelf region, allowing a more definitive correlation with coeval glendonite occurrences across the Arctic realm and with global climatic changes during the Jurassic-Cretaceous.

Southern Ocean Oxygenation Changes Inferred From Redox‐Sensitive Trace Metals Across Marine Isotope Stage 11

Year: 2021
Products: PC-3
Authors: Rohde, E;Hayes, C;Redmond, N;Glasscock, S;
Application: Dissolved;isotope;

Changes in the circulation of the Southern Ocean are known to have impacted global nutrient, heat, and carbon cycles during the glacial and interglacial periods of the late Pleistocene. Proxy-based records of these changes deserve continued scrutiny as the implications may be important for constraining future change. A record of authigenic uranium from the South Atlantic has been used to infer changes in deep-sea oxygenation and organic matter export over the past 0.5 million years. Since sedimentary uranium has the possible complication of remobilization, it is prudent to investigate the behavior of other redox-sensitive trace metals to confidently interpret temporal changes in oxygenation. Focusing here on the exceptionally long interglacial warm period, Marine Isotope Stage (MIS) 11, we found concurrent authigenic enrichments of uranium (U) and rhenium (Re) throughout MIS 12 to 10, overall supporting prior interpretations of low-oxygen periods. However, there are differential responses of Re and U to oxygen changes and some evidence of small-scale Re remobilization, which may involve differences in molecular-level reduction mechanisms. Peaks in authigenic manganese (Mn) intervening with peaks in Re and U indicate increases in porewater oxygenation which likely relate to increased Antarctic Bottom Water circulation at the onset of MIS11c and during the peak warmth of the interglacial around 400 ka.

Rutile and Chlorite Geochemistry Constraints on the Formation of the Tuwu Porphyry Cu Deposit, Eastern Tianshan and Its Exploration Significance

Year: 2021
Products: laser ablation system
Authors: Wen, X;Zhang, F;Wang, Y;Sun, M;Zhang, W;Li, Y;Zhou, H;Chen, Y;
Application: Laser;geochemistry;

The chemical composition of rutile has been used as an indicator in magmatic and metamorphic-related diagenetic systems, but rarely in porphyry-style ore systems. The Tuwu deposit (557 Mt at 0.58% Cu) is a large porphyry-style Cu mineralization in Eastern Tianshan, Xinjiang, with typical disseminated, stockwork mineralized veins hosted in tonalite and diorite porphyry, and to a lesser extent in volcanic rocks of the Qi’eshan Group. We first present determination of rutile minerals coupled with chlorite identified in mineralized porphyries from Tuwu to reveal their geochemical features, thus providing new insights into the ore-forming processes and metal exploration. Petrographic and BSE observations show that the rutile generally occurs as large crystals (30 to 80 µm), in association with hydrothermal quartz, chlorite, pyrite, and chalcopyrite. The rutile grains display V, Fe, and Sn enrichment and flat LREE-MREE patterns, indicating a hydrothermal origin. Titanium in rutile (TiO2) is suggested to be sourced from the breakdown and re-equilibration of primary magmatic biotite and Ti-magnetite, and substituted by Sn4+, high field strength elements (HFSE; e.g., Zr4+ and Hf4+), and minor Mo4+ under hydrothermal conditions. The extremely low Mo values (average 30 ppm) in rutile may be due to rutile formation postdating that of Mo sulfides (MoS2) formation in hydrothermal fluids. Chlorite analyses imply that the ore-forming fluids of the main stage were weakly oxidized (logfO2 = −28.5 to −22.1) and of intermediate temperatures (308 to 372 °C), consistent with previous fluid inclusion studies. In addition, Zr-in-rutile geothermometer yields overestimated temperatures (>430 °C) as excess Zr is incorporated into rutile, which is likely caused by fast crystal growth or post crystallization modification by F-Cl-bearing fluid. Thus, application of this geothermometer to magmatic-hydrothermal ore systems is questionable. Based on the comparison of rutile characteristics of porphyry Cu with other types of ore deposits and barren rocks, we suggest that porphyry Cu-related rutile typically has larger grain size, is enriched in V (average 3408 ppm, compared to <1500 ppm of barren rocks) and to a lesser extent in W and Sn (average 121 and 196 ppm, respectively), and has elevated Cr + V/Nb + Ta ratios. These distinctive signatures can be used as critical indicators of porphyry-style Cu mineralization and may serve as a valuable tool in mineral exploration.

Garnet as Indicator of Pegmatite Evolution: The Case Study of Pegmatites from the Oxford Pegmatite Field (Maine, USA)

Year: 2021
Products: 231 nm ESI NWR 213 laser
Authors: Hernández-Filiberto, L;Roda-Robles, E;Simmons, W;Webber, K;
Application: Laser;

Almandine-spessartine garnets, from the Oxford County pegmatites and the Palermo No. 1 pegmatite, record significant compositional variations according to the degree of evolution of their hosting rock. Garnets from the most fractionated pegmatites (Mt. Mica, Berry-Havey, and Emmons) show the highest Mn, Nb, Ta, Zr, and Hf values, followed by those from the intermediate grade pegmatites (Palermo No. 1) and, finally, garnets from the barren pegmatites show the lowest values (Perham and Stop-35). Iron, Ca, and Mg contents follow an inverse order, with the highest contents in the latter pegmatites. Major element zoning shows increasing Mn values from core to rim in most garnet samples, while trace element zoning is not systematic except for some crystals which show a core to rim depletion for most of these elements. Chondrite normalized HREE (Heavy Rare Earth Elements) spectra show positive slopes for garnets from barren pegmatites, both positive and negative slopes for those associated with the intermediate pegmatite, and negative or flat slopes in garnets from the highly fractionated pegmatites. Ion exchange mechanisms, including Fe2+−1Mn2+1, (Fe2+, Mn2+)−1Si−1Li1P1; and, (Y, Ho3+)2(vac)1(Fe2+, Mn2+)−3, could explain most of the compositional variations observed in these garnets. These compositional variations are the reflection of the composition of the pegmatitic magma (barren pegmatites originate from a more ferromagnesian magma than fractionated pegmatites); and of the coexisting mineral phases competing with garnets to host certain chemical elements, such as biotite, schorl, plagioclase, apatite, Fe-Mn phosphates, Nb-Ta oxides, zircon, xenotime, and monazite.

Ex and In Situ Reactivity and Sorption of Selenium in Opalinus Clay in the Presence of a Selenium Reducing Microbial Community

Year: 2021
Products: MicroFlow PFA-ST concentric nebulizer
Authors: Bleyen, N;Small, J;Mijnendonckx, K;Hendrix, K;Albrecht, A;De Cannière, P;Surkova, M;Wittebroodt, C;Valcke, E;
Application: Species;

79Se is a critical radionuclide concerning the safety of deep geological disposal of certain radioactive wastes in clay-rich formations. To study the fate of selenium oxyanions in clayey rocks in the presence of a selenium reducing microbial community, in situ tests were performed in the Opalinus Clay at the Mont Terri Rock Laboratory (Switzerland). Furthermore, biotic and abiotic batch tests were performed to assess Se(VI) and Se(IV) reactivity in the presence of Opalinus Clay and/or stainless steel, in order to support the interpretation of the in situ tests. Geochemical modeling was applied to simulate Se(VI) reduction, Se(IV) sorption and solubility, and diffusion processes. This study shows that microbial activity is required to transform Se(VI) into more reduced and sorbing Se species in the Opalinus Clay, while in abiotic conditions, Se(VI) remains unreactive. On the other hand, Se(IV) can be reduced by microorganisms but can also sorb in the presence of clay without microorganisms. In situ microbial reduction of Se oxyanions can occur with electron donors provided by the clay itself. If microorganisms would be active in the clay surrounding a disposal facility, microbial reduction of leached Se could thus contribute to the overall retention of Se in clayey host rocks.

Where do you come from, where do you go: Early life stage drift and migrations of cod inferred from otolith microchemistry and genetic population assignment

Year: 2021
Products: NWR213 frequency-quintupled Nd:YAG solid state laser 175 system
Authors: Hüssy, K;Albertsen, C;Hemmer-Hansen, J;Vinther, M;Serre, S;Thomsen, T;Eero, M;
Application: Laser;

This study investigates stock mixing of genetically distinct Atlantic cod (Gadus morhua) stocks in the Kattegat, an area geographically located between the North Sea and the Baltic Sea, by combining genetic population identification with habitat assignments from hatch to capture from otolith microchemistry. Cod captured in Kattegat were genetically assigned to either the North Sea or the endemic Kattegat population. Otolith chemical fingerprints differed significantly between populations during the larval and pelagic juvenile stage with higher strontium and lower barium and manganese concentrations in the North Sea population than the Kattegat population, indicating that North Sea cod are spawned in the North Sea or Skagerrak and drift into the Kattegat during the early life stages. Individual cod of both populations undertook frequent migrations to other areas, with < 25 % of individuals remaining resident within the Kattegat throughout their life. Across seasons and age classes, the two populations were most frequently distributed in the Kattegat (67 %), with approximately 25 % distributed in the western Baltic Sea and < 10 % in the Skagerrak/North Sea.


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