Rb Concentrations Research Articles

Post-collisional, high-Ba-Sr Teixeira Batholith granites: Evidence for recycling of Paleoproterozoic crust in the Alto Pajeú domain, Borborema Province – NE-Brazil

Late-Neoproterozoic granitoids of diversified nature and ages (640–525 Ma) are widely distributed in the Borborema Province and their petrogenesis can provide important insights about the Brasiliano/Pan-African Orogeny (ca. 650–550 Ma). The Neoproterozoic Teixeira Batholith comprises an ENE – elongated intrusion of c. 800 km2 emplaced in metasedimentary rocks and orthogneisses in central Borborema Province immediately south of the Patos Shear Zone. Textures and modal mineral percentage allow to divide the batholith into six petrographic facies, ranging in composition from monzogranite to quartz syenite, containing less than 10% of modal mafic mineral phases (amphibole ± clinopyroxene and biotite). Titanite, epidote, apatite, zircon and Fe-Ti oxide are the main accessory phases. LA-ICP-MS U-Pb zircon data from four facies yield ages ranging from 585 to 600 Ma, like other Neoproterozoic pre- to early-transcurrent intrusions related to the Brasiliano orogeny. The granitoids belong to the magnetite series, are metaluminous and have high-K calk-alkaline to shoshonitic affinities. Major and trace elements data are typical of granites originating from high barium‑strontium (HiBaSr) magmas, i.e., high Ba (1825–7370 ppm), Sr (1110–2530 ppm), low Rb (56–137 ppm), Th (1.6–15.8 ppm), Nb (6.2–34.7 ppm), Y (3.7–33.2 ppm) and HREE contents (Gd-Lu: 3.64–24.36 ppm). The granitoids have negative ƐNd(590Ma) (−13.68 to −16.04) and ƐHf(t) (−16.27 to −20.80) values, and Paleoproterozoic Nd and Hf TDM model ages ranging from 2.08 to 2.23 and 2.3 to 2.6, respectively, similar to the ages of basement rocks of the Central subprovince. The isotopic data and trace elements signature suggest magma generation by partial melting of Paleoproterozoic mafic/intermediate lower crust, leaving a plagioclase-free and garnet and/or amphibole-bearing residue. Partial melting occurred after a long period of contractional tectonics, and predated development of the Patos shear zone by ca. 20 Ma.

Geochronological framework and ore genesis of the Tiantangshan Rb-Sn-W deposit, northeastern Guangdong, south China: Constraints from cassiterite and monazite U-Pb dating

The newly discovered Tiantangshan Rb-Sn-W deposit in the northeastern Guangdong is one of the largest Rb deposit in China. The deposit is hosted by volcanic rocks and characterized by hydrothermal mineralization of Rb and Sn-W, with minor Rb mineralization of granitic K-feldspar alteration. In this study, we conducted LA-ICP-MS U-Pb dating of cassiterite and monazite to constrain the ore-forming ages of Sn and Rb. Two stages of cassiterite (Cst) are developed in the wolframite-cassiterite quartz vein, and the Cst I and Cst II yielded weighted mean 206Pb/238U ages of 133.9 ± 2.0 Ma and 133.2 ± 1.6 Ma, respectively. Monazites from biotite quartz vein yielded weighted mean 206Pb/238U ages of 134.2 ± 1.8 Ma and 132.7 ± 1.1 Ma. Combined with previous studies, a geochronological framework of volcanic eruptions (ca. 137 Ma), alkali feldspar granite (ca. 136 Ma) and Rb-Sn mineralization (134 to 133 Ma) for the deposit was established. Thus, the Rb-Sn-W mineralization is genetically related to the alkali feldspar granite and a volcanic-intrusive connection. Most Rb resources of the deposit are hosted by hydrothermal biotite in biotite quartz vein and related biotite alteration of volcanic wall rocks. Meanwhile, the K-feldspar alteration of the alkali feldspar granite displays higher Rb contents (1992–2092 ppm), stronger REE tetrad effect and lower Zr/Hf, Nb/Ta and Y/Ho ratios than the unaltered granite, indicating important involvement of hydrothermal fluids in this type of Rb enrichment. In combination with recent age data, the Tiantangshan deposit, with Yanbei and Taoxihu in the southeastern Jiangxi, are related to the numerous Sn deposits in southeastern Guangdong, which together form an early Cretaceous Sn metallogenic belt in South China. The early Cretaceous Sn belt was formed under an extensional environment likely due to the roll back of the subducted paleo-Pacific plate. The Tiantangshan deposit is indicative of Sn and related rare-metal exploration potential in the early Cretaceous volcanic basins in adjacent areas.

Isotope-Geochemical Features of Apoultrabasic Metasomatites of the Sayan–Baikal Folded Area

Abstract —The paper is concerned with a geochemical study of apoultrabasic metasomatites of the Ospa–Kitoi, Parama, and Ust’-Kelyana ophiolite massifs located in the southern folded framing of the Siberian craton. The isotope (O, C, H, Sr, and Rb) systems of dunites, serpentinites, nephrites, listvenites, and talc–carbonate rocks are studied. The isotopic composition of oxygen in olivines from dunites is characterized by δ18O = 4.6–5.5‰. The δ18O values of serpentinites (4.67–7.35‰) point to the mantle genesis of fluids and might have been inherited from ultrabasic rocks. Nephrites are slightly enriched in heavy oxygen isotope (δ18O = 6.13–9.54‰). This indicates that their fluid phase was transported from serpentinites and captured a small portion of the crustal component. The widest variations in δ18O values, from 8.12 to 17.46‰, are observed in minerals from listvenites. Carbonates from these rocks show a highly heterogeneous isotopic composition of oxygen (δ18O = 12.9–18.8‰) and carbon δ13C = –2.8 to +2.8‰). These rocks formed with the contribution of metamorphogenic fluids. According to the isotopic composition of hydrogen, the examined serpentinites are divided into two groups: with δD values specific to “magmatic water” (δD = –73.50 to –85.00‰) and those typical of meteoric fluids (δD = –151.90 to –167.20‰). The listvenites are characterized by low Rb and high Sr contents. Their 87Sr/86Sr values (0.70702–0.70971) indicate the contribution of a crustal source. The study of fluid inclusions in minerals from listvenites has shown that the rocks formed under relatively low-temperature conditions. The homogenization temperatures of fluid inclusions in quartz and magnesite from listvenites of the Ospa–Kitoi massif are 184–290 ºC and 122–182 ºC, respectively. In the Parama massif, the homogenization temperature of fluid inclusions in quartz is 130–170 ºC. The solutions that formed listvenites of the Ospa–Kitoi massif were slightly saline (TDS = 2.9–8.4 wt.% NaCl eq.), with NaCl and Na2CO3 being the main salt components.

Quartz chemistry of granitic pegmatites: Implications for classification, genesis and exploration

Quartz from 254 pegmatites representing eight pegmatite fields and provinces worldwide was investigated by laser-ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) to determine concentrations of trace elements Al, Ti, Li, Ge, B, Be, Rb, Na, K, Ca, P, Ga, Sb, Zn and U. A total of 271 new analyses combined with 535 published LA-ICP-MS quartz chemistry data were evaluated with binary and ternary trace element discrimination plots and principal component analysis (PCA). The classifications applied for discrimination of pegmatite types include the widely applied NYF(Nb-Y-F) - LCT(Li-Cs-Ta) classification and the new RMG (pegmatites derived from residual melts of granite magmatism) - DPA (pegmatites as direct products of anatexis) grouping. Pegmatites of both classifications can be well distinguished via Al-Ti, Al-Li and Al/Ti-Ge/Ti binary trace element plots and the Ti - Al/10 - 10*Ge ternary diagram. PCA applied to Al, Li, Ti, Be, B, Ge and Rb contents in quartz allowed to further distinguish between anatectic DPA-1 (Li-enriched DPA) and granite-pluton-derived RMG-1 (Li-enriched RMG) pegmatites. Some pegmatite fields and provinces (Hagendorf-Pleystein, Oxford County) are distinguishable by region-specific Li, Ge and Al contents. The results imply that the chemistry of pegmatite quartz is mainly controlled by the origin (source rock chemistry) of pegmatite melts and, to a much lesser extent, by the geodynamic setting of the pegmatite fields and provinces. Chemically primitive NYF and DPA-2 type pegmatites contain quartz with the lowest total trace-element contents and lowest internal-pegmatite trace-element variation, making it potentially suitable for high-tech application. Pegmatite quartz containing >30 μgg-1 Li and >100 μgg-1 Al is strongly indicative of economic spodumene/montebrasite mineralization and, thus, serves as a strong Li-mineralization pathfinder mineral. Quartz with >5 μgg-1 B may be a potential indicator for gem-quality tourmaline mineralization.

Decoupling of Sr-Nd Isotopic Composition Induced by Potassic Alteration in the Shapinggou Porphyry Mo Deposit of the Qinling–Dabie Orogenic Belt, China

In our previous study on petrogenesis of quartz syenite and granite porphyry, the host rocks of the Late Mesozoic Shapinggou Mo deposit in the Qinling–Dabie orogenic belt, we found that the initial Sr isotopic composition of the host rocks is strongly affected by the degree of K-alteration. Here, we provide further isotopic evidence of the host rocks and their minerals to investigate the geochemical behaviour of trace elements and isotopes during the alteration and to explain the phenomenon of decoupling of Sr–Nd isotopic composition. The quartz syenite and granite porphyry are altered by K-alteration in varying degrees and have high K2O and Rb contents and low Na2O, CaO, Sr, and Ba contents. Rock samples of both quartz syenite and granite porphyry have variable Rb/Sr ratios and initial 87Sr/86Sr values (even < 0.70) but contain quite homogeneous εNd(t) values (−12.8 to −14.8). Minerals from the rocks of moderate to intense K-alteration have very low initial 87Sr/86Sr values (even < −17), while those from the weakly altered rocks have 87Sr/86Sr(t) values of 0.7044 to 0.7084. The same phenomenon of the decoupling in Sr–Nd isotopic composition can be observed from several Mo deposits within the eastern Qinling–Dabie orogenic belt. This fact suggests similar hydrothermal features and a comparable origin for both the magmatic rocks and hydrothermal fluids in this belt. A comparison between porphyry Mo and porphyry Cu deposits shows that elements and the Rb–Sr isotope system have different behaviours during the K-alteration, implying distinct material sources and igneous rocks for porphyry Mo and porphyry Cu deposits, respectively.

Application of ground magnetic and soil geochemical surveys for mapping potential kimberlite bodies in the southern margin of the Archaean Kaapvaal Craton, South Africa

In this study, the southern margin of the Archean Kaapvaal Craton in South Africa is selected to investigate the occurrences of potential kimberlite bodies. Ground magnetic survey was conducted to identify potential targets for further exploration. Euler 3D deconvolution and Keating correlation coefficients are the processing techniques that were applied to the ground magnetic data to identify geological features that correspond to kimberlite models. These techniques revealed several potential targets that resemble geologic models of kimberlite bodies. Seven of these targets (Targets A, B, C, D, E, F and G), spatially cluster along or at the intersections of linear structures, which is consistent with one of the primary geological conditions that control the emplacement of kimberlite bodies. A follow-up soil sampling and analysis was conducted to assess the geochemistry of soils at the seven targets. The major element geochemistry of soil samples suggest that Target B possesses residual soils that originated from kimberlite intrusion, while the remaining six samples show geochemical characteristics of soils derived from crustal rocks. The composition of compatible (Ni, Cr, V, Co, Cu and Zn) and incompatible (Nb, Zr, Sr, Ce, and Ba) trace elements of Target B shows similarity with the known Group 1 Kimberlites locally and globally, thus confirming that Target B most probably belongs to Group 1 Kimberlite petrological clan. This, however, does not preclude the possibility of modification of kimberlite chemistry by crustal assimilation during ascent and post-emplacement processes such as weathering as demonstrated by elevated concentrations of SiO2, Al2O3 and Rb and low content of MgO. In light of this, Target B may be interpreted as a potentially contaminated and weathered Group 1 Kimberlite pipe which intruded the Karoo Supergroup at the intersection of linear structures. This finding is consistent with the presence of large number of known diamondiferous kimberlites in this region, which post-date the formation of the Karoo Supergroup.

Origin of high Ba-Sr granitoids at Chigou in central China and implications for Cu mineralization: Insights from whole-rock geochemistry, zircon U–Pb dating, Lu–Hf isotopes and molybdenite Re–Os systematics

The Chigou copper deposit is situated in the southern part of the Qinling orogenic belt, central China, where quartz diorite and quartz diorite porphyry are associated with porphyry-type copper mineralization. Copper generally occurs as veins, veinlets, and disseminations within-host porphyries. The zircon dates tightly constrain the timing of host porphyries to ca. 149–146 Ma, in agreement with the age of porphyry copper mineralization (146.1 ± 2.8 Ma) constrained by using molybdenite Re–Os dating. The calculated zircon ΔFMQ values for quartz diorite are −9.4 to +9.9 (averaging +4.3). The Chigou granitoids show similar geochemical compositions to high-Barium-Strontium (high Ba-Sr) granites, with high Ba (2256–3717 ppm) and Sr (737–1345 ppm), low Rb (86.2–129 ppm), U (1.9–4.7 ppm), Th (16.2–31.2 ppm), and Nb (11.4–19.1 ppm) concentrations, as well as lack of negative Eu anomalies. The concentrated εHf(t) values (−3.0 to +1.4), moderate Mg# values (41–52), and high (Hf/Sm)PMN and La/Sm ratios, but low Ba/Th, U/Th, and (Ta/La)PMN ratios indicate that ore-forming magmas derived from an enriched lithospheric mantle that had been metasomatized by subducted sediment-derived melts with a minor crustal contribution. Combined with previous studies, we suggest that the Chigou deposit formed in a post-collisional tectonic setting during the Late Jurassic.

Petrology and geochemistry of the Archean Huangling greenstone belt in the Yangtze Craton, South China

The Archean Huangling greenstone belt (HGB) is preserved as amphibolites in the Huangling granite–greenstone terrane, Yangtze Craton. Geologically and geochemically, the amphibolites are metavolcanic rocks and can be subdivided into amphibole schist, massive amphibolite and banded amphibolite, with komatiite, komatiitic basalt and tholeiitic basalt protoliths, respectively. The komatiites have high MgO (20–30%), Cr, Co and Ni contents; low Rb, Sr, Ba and ΣREE contents; and slight LREE depletion and HREE enrichment, characterizing them as the Al-undepleted type according to the criteria (CaO/Al2O3)adj ˃ 20, (Al 2O3/TiO2)adj and (Gd/Yb)PM < 1. The komatiitic basalts and tholeiitic basalts have lower MgO (5–16%), Cr, Co and Ni contents; higher Rb, Sr, Ba and ΣREE contents; and slight LREE enrichment and HREE depletion. The geochemical plots (Zr/Y vs. Nb/Y, Nb/Yb vs. Th/Yb, La/Ta vs. La/Sm and Y vs. Zr/Y), negative Nb anomalies, wide ƐNd values (−8.0 to +6.2), negative zircon ƐHf values (−11.59 to −3.98), and old TNd (DM) (3.9–2.9 Ga) and zircon THf (DM) ages (3.9–3.3 Ga) of the amphibolites reflect a mantle source with slight crustal contamination and show that the komatiitic basalts and tholeiitic basalts are more closely related to each other than to the komatiites. The tholeiitic basalts originated from moderate-degree melting of a mantle plume head, the komatiitic basalts originated from the fractional crystallization of tholeiitic basalt melts as cumulates, and the komatiites originated from high-degree melting of the mantle plume tail with garnet entering the melt phase. These high-Mg lavas erupted in a continental rift when the mantle plume impinged on the continental lithosphere, generating rifting and subsequent volcanic eruptions. These ultramafic–mafic rocks (3.2–3.0 Ga) formed the HGB, which was subsequently intruded by TTG (3.0–2.9 Ga), together forming the Archean Huangling granite–greenstone terrane in the Yangtze region.

Evidence for magma mixing during Triassic magmatism in West Qinling, China: Constraints from petrology, geochemistry, U–Pb zircon geochronology, and Sr–Nd–Hf isotopic of the Baguashan pluton

The West Qinling Orogen, which forms the western part of the Qinling Orogenic Belt, is characterized by the voluminous distribution of Triassic granitoids. Here, we investigate the Baguashan monzogranite which hosts numerous mafic microgranular enclaves (MMEs). We present zircon U–Pb–Hf and whole‐rock geochemical as well as Sr–Nd isotopic data of the monzogranites and MMEs with a view to gain insights on the petrogenesis and geodynamic setting. Zircon LA‐ICP‐MS U–Pb dating yields ages of 219.0 ± 1.7 Ma and 219.5 ± 1.6 Ma for the MMEs, and 214.2 ± 1.3 Ma for the host monzogranite, suggesting formation from coeval magmas. The host monzogranites show high SiO2, Rb, Ba, and Th contents, but low TiO2, MgO, P2O5 values, with A/CNK of &lt;1.1. Zircon grains from monzogranites show εHf(t) values in the range of −6.3 to +3.2 with corresponding two‐stage Hf model ages (TDM2) of 1.39–2.25 Ga. The MMEs are mostly elliptical or spherical in shape and have lower SiO2 and Th contents, but higher MgO, TiO2, and CaO, and εHf(t) values ranging from −6.1 to +5.7 with TDM2 of 1.17–2.23 Ga. The Sr–Nd isotopic data for MMEs and monzogranites show (87Sr/86Sr)i ratios ranging from 0.7059 to 0.7069 and low εNd(t) values ranging from −6.07 to −4.18, suggesting a crustal origin. Based on the relatively homogeneous Sr–Nd–Hf isotopic compositions, we suggest that the MMEs represent magma mixing, and the mafic magma injected into the felsic magma chamber was probably derived by the reworking of mafic lower crust with a contribution of juvenile materials. We propose a model involving delamination of thickened lower crust below the West Qinling Orogen after the collision between the North China Block and the South China Block in the Late Triassic. Subsequently, the lower crust was partially melted by the heat input from the upwelling asthenosphere and produced the mafic magma. Partial melting of the ancient metamorphic rocks generated the granitic magma. The interaction of mafic and felsic magmas occurred within a post‐collisional tectonic setting in the Late Triassic.

Magmatic and hydrothermal evolution of highly-fractionated rare-metal granites at Gabal Nuweibi, Eastern Desert, Egypt

The Nuweibi intrusion was emplaced during the final tectono-magmatic stage of Arabian-Nubian Shield development (ANS). Two cogenetic phases of intrusion can be recognized in the field: the early phase is represented by porphyritic albite granite and the final phase by non-porphyritic albite granite. Mineralogically, both phases are essentially composed of albite, quartz, and K-feldspars with subordinate muscovite. Accessory minerals include fluorite, zircon, NbTa oxides, cassiterite, beryl, topaz, and garnet. Geochemically, the Nuweibi intrusion consists of extensively fractionated rare-metal granite with low contents of TiO2, FeOt, CaO, MgO, P2O5, Sr, and Ba in contrast to elevated concentrations of alkalis, Rb, Nb, Ta, and Hf. Their peraluminous (molar Al2O3/[CaO + Na2O + K2O] = 1.06–1.15) and low-P (P2O5 < 0.008 wt%) character identify them as highly fractionated I-type granites. The primary magma of the Nuweibi intrusion was most likely generated by partial melting of the juvenile crust of the ANS. We document numerous lines of evidence that the Nuweibi albite granite was formed by extensive fractional crystallization followed by interaction with magmatically-derived, F-rich hydrothermal solutions. The REE patterns of the Nuweibi albite granite show marked negative Eu anomalies (Eu/Eu⁎ = 0.01–0.15) as well as prominent M-type tetrad effects (TE1,3 = 1.332–3.536), typically seen in highly differentiated granites and attributed to exchange with hydrothermal fluid. Anomalous ratios of isovalent “twin” elements such as Nb/Ta, Zr/Hf, and Y/Ho likewise indicate exchange with hydrothermal fluid. The primary rare-metal accessory minerals are restricted to the Mn-rich part of the columbite-tantalite series; this manganoan trend is characteristic of highly fractionated granites. Likewise, the presence of wodginite, a Sn-bearing mineral, is a unique fingerprint of highly evolved rare-metal granites. Late-stage hydrothermal overprint of the primary rare-metal mineralization is preserved by rims of fluorcalciomicrolite partly replacing columbite-(Mn) and tantalite-(Mn). Accumulation of residual volatile-rich melt and exsolved fluids in the upper part of the magma chamber produced stockscheider pegmatite, greisen, and quartz veins that cut the peripheries of the Nuweibi intrusion and the surrounding country rocks.

Nurse sharks, space rockets and cargo ships: Metals and oxidative stress in a benthic, resident and large-sized mesopredator, Ginglymostoma cirratum

It is widely recognized that apex predators, such as large sharks with highly migratory behavior, are particularly vulnerable to pollution, mainly due to biomagnification processes. However, in highly impacted areas, mesopredator sharks with resident behavior can be as vulnerable as apex sharks. In this context, this study evaluated cadmium (Cd), mercury (Hg), lead (Pb), and rubidium (Rb) concentrations, as well as the potentially protective effects of selenium (Se) and the behavior of two non-enzymatic biomarkers, metallothionein (MT) and reduced glutathione (GSH), employing the Atlantic nurse shark Ginglymostoma cirratum as a study model and compared the results with other resident benthic sharks, as well as highly mobile apex sharks. Muscle tissue samples from 28 nurse sharks opportunistically sampled from the Brazilian Amazon Coast were analyzed. Lower metal concentrations were observed for Pb, Rb and Se in the rainy season, while statistically significant correlations between metals were observed only between Hg and Cd and Pb and Se. Molar ratio calculations indicate potential protective Se effects against Pb, but not against Cd and Hg. No associations between MT and the determined metals were observed, indicating a lack of detoxification processes via the MT detoxification route. The same was noted for GSH, indicating no induction of this primary cellular antioxidant defense. Our results indicate that benthic/mesopredator sharks with resident behavior are, in fact, as impacted as highly mobile apex predators, with the traditional detoxification pathways seemingly inefficient for the investigated species. Moreover, considering the studied population and other literature data, pollution should be listed as a threat to the species in future risk assessments.

Detrimental and essential elements in fruiting bodies of mushrooms with ecological relationship to birch (Betula sp.) collected in the Bohemian Forest, the Czech Republic.

Four macrofungi species with ecological relationship to birch (Betula sp.) were analyzed with regard to the content of 21 detrimental and essential elements in their fruiting bodies. Two of the species (Leccinum scabrum and Leccinum versipelle) were mycorrhizal forming edible fruiting bodies while the others (Fomitopsis betulina and Inonotus obliquus) parasitic used in alternative medicine. The samples were collected near the town of Vimperk in the Bohemian Forest, the Czech Republic. L. scabrum accumulated Ag, Rb, Cd, Cs, Se, Cu, and Zn with bioconcentration factors of 22, 5.5, 4.7, 3.2, 2.0, 1.7, and 1.4, respectively. Similar trend in bioconcentration was revealed for L. versipelle with bioconcentration factors of 28, 5.2, 2.4, 1.9, 1.6, and 1.6 determined for Ag, Rb, Cu, Se, Zn, and Cd, respectively. Considerably high contents of Ca (400 ± 190 mg kg-1 dry matter), Fe (110 ± 30), Mg (1100 ± 300), and Zn (220 ± 90) were found in F. betulina. Similarly, high contents of Ca (1000 ± 700 mg kg-1 dry matter), Fe (110 ± 30), Mg (2000 ± 1100), Mn (410 ± 270), Rb (160 ± 60), and Zn (140 ± 70) were determined for I. obliquus. The different lifestyles (mycorrhizal vs. parasitic) were reflected in 13 significant differences of element contents.

Comparison of Minimally Invasive Inductively Coupled Plasma-Mass Spectrometry Approaches for Strontium Isotopic Analysis of Medieval Stained Glass with Elevated Rubidium and Rare-Earth Element Concentrations.

Different approaches for the determination of the 87Sr/86Sr isotope ratio of high-Rb glass are compared in this work to assess the suitability of minimally invasive approaches for applications on medieval stained glass (from the ancient Abbey of Stavelot in Belgium). It was found that pneumatic nebulization multicollector inductively coupled plasma–mass spectrometry (PN-MC-ICP-MS) after acid digestion and chromatographic isolation of the target analyte out of the sample matrix can still be seen as the preferred method for the high-precision isotopic analysis of Sr in glass with high Rb and rare-earth element (REE) concentrations. Alternatively, the use of laser ablation (LA) for sample introduction is a powerful technique for the direct analysis of solid samples. However, both the high Rb/Sr ratios in the samples of interest and the presence of REEs at sufficiently high concentrations lead to a large bias in LA-MC-ICP-MS, which cannot be corrected for, even by operating the MC-ICP-MS instrument at higher mass resolution and/or using mathematical corrections. It was demonstrated that LA tandem-ICP-MS (LA-ICP-MS/MS) using CH3F/He as the reaction gas to overcome spectral overlap in a mass-shift approach (chemical resolution) provides a viable alternative when (quasi) nondestructive analysis is required. This approach relies on the monitoring of Sr+ (m/z = 86, 87, and 88) ions as the corresponding SrF+ reaction product ions (m/z = 105, 106, and 107), thus avoiding the occurrence of spectral interference. Self-evidently, the isotope ratio precision attainable using sequential quadrupole-based ICP-MS instrumentation (0.3% RSD) was found to be significantly worse than that of high-precision MC-ICP-MS (0.03% RSD) with simultaneous detection, although it was still fit for the purpose of current applications. In addition to Sr isotopic analysis, the REE patterns and their potential influence on the Sr isotopic composition were evaluated by LA-ICP-MS.

Geochemical behavior of rare metals and high field strength elements during granitic magma differentiation: A record from the Borong and Malashan Gneiss Domes, Tethyan Himalaya, southern Tibet

In the Borong Gneiss Dome and Malashan Gneiss Dome within the Tethyan Himalaya, zircon UPb ages and whole-rock geochemical data demonstrate that at least two episodes of leucogranite formed at 19.8–19.4 Ma and 18.6–18.5 Ma, respectively. Each of them contains at least two suites of granite: two-mica granite and garnet-bearing leucogranite. Although the two types of granites are characterized by distinct element geochemistry and mineral compositions, they show similar Sr-Nd-Hf isotope ratios and regular variations in the compositions of whole-rock elements. From two-mica granite to garnet-bearing leucogranite, SiO2, Na2O, Rb, Nb, and Ta contents and Rb/Sr ratios increase; in contrast, Al2O3, CaO, MgO, FeO, TiO2, Sr, Ba, Eu, Zr, U, Th, light rare earth elements (LREEs) and Sc contents, as well as Zr/Hf and Nb/Ta ratios, decrease. Such systematic variations imply that two-mica granite and garnet-bearing leucogranite are cogenetic and that two-mica granite represents the more primary melt, whereas garnet-bearing leucogranite is a more evolved melt. During granitic magma evolution, fractional crystallization induces substantial changes in the melt structure and in turn major changes in the dissolution behavior of accessory phases (e.g., zircon, monazite, and apatite) and the geochemistry of key trace elements. Such changes might be the key factors that resulted in the subordinate W-Sn-Nb-Ta-Be anomalies in the more evolved granites, which implies that the Himalayan Cenozoic leucogranites have high potential to produce economic rare metal deposits.

Metabolomic, Ionomic and Microbial Characterization of Olive Xylem Sap Reveals Differences According to Plant Age and Genotype

Vascular pathogens are the causal agents of main diseases threatening the health and growth of olive crops worldwide. The use of endophytic microorganisms represents a challenging and promising strategy for management of vascular diseases in olive. Although current research has been focused on analyzing the structure and diversity of the endophytic microbial communities inhabiting the olive xylem, the characterization of this ecological niche has been overlooked and to date remain unexplored, despite that the characterization of the xylem sap composition is essential to unravel the nutritional requirements of xylem-limited microorganisms. In this study, branches from plantlets and adult olive trees of cultivars Picual and Arbequina were selected to characterize the chemical and microbial composition of olive xylem sap extracted using a Scholander pressure chamber. Metabolome and ionome analyses of xylem sap were performed by proton nuclear magnetic resonance (NMR) spectroscopy-based and by inductively coupled plasma with optical emission spectroscopy (ICP-OES), respectively. Olive xylem sap metabolites included a higher relative percentage of sugars (54.35%), followed by alcohols (28.85%), amino acids (8.01%), organic acids (7.68%), and osmolytes (1.12%). Within each of these groups, the main metabolites in the olive xylem sap were mannitol, ethanol, glutamine, acetic acid, and trigonelline, whereas K and Cl− were the main element and inorganic anion, respectively. Metabolomic profile varied when comparing olive plant age and genotype. The levels of glucose, fructose, sucrose and mannitol, choline, B and PO43− were significantly higher in adult trees than in plantlets for both olive genotypes, whereas NO3− and Rb content showed the opposite behavior. On the other hand, levels of aspartic acid, phenylalanine, and Na were significantly higher in ‘Picual’ than in ‘Arbequina’, whereas Fe showed the opposite behavior, but only for adult trees. Microbiome composition identified Firmicutes (67%), Proteobacteria (22%) and Actinobacteriota (11%) as the main phyla, while at the genus level Anoxybacillus (52%), Cutibacterium (7%), Massilia (6%), and Pseudomonas (3%) were the most representative. Both non-supervised hierarchical clustering analysis and supervised PLS-DA analysis differentiated xylem sap chemical and microbial composition first, according to the age of the plant and then by the olive genotype. PLS-DA analysis revealed that B, ethanol, Fe, fructose, glucose, mannitol, sucrose, and Sr, and Anoxybacillus, Cutibacterium, and Bradyrhizobium were the most significant chemical compounds and bacterial genera, respectively, in the discrimination of adult olive trees and plantlets. Knowledge of the chemical composition of xylem sap will lead to a better understanding of the complex nutritional requirements of olive xylem-inhabiting microorganisms, including vascular pathogens and their potential antagonists, and may allow the better design of artificial growing media to improve the culturing of the olive microbiome.

Determination of 87Rb/86Sr and 87Sr/86Sr ratios and Rb–Sr contents on the same filament loading for geological samples by isotope dilution thermal ionization mass spectrometry

Isotope dilution thermal ionization mass spectrometry (ID-TIMS) is considered the “gold standard” for obtaining precise 87Rb/86Sr and 87Sr/86Sr isotope ratios and accurate elemental concentrations of Rb–Sr. However, the classical ID-TIMS technique is laborious and time-consuming because the purified Rb and Sr fractions must be individually loaded onto different independent filaments due to severe 87Rb isobaric interference on 87Sr. To overcome this issue, we developed a new method whereby Rb and Sr were sequentially measured by TIMS on the same filament, without venting, to obtain both ratios of 87Rb/86Sr and 87Sr/86Sr and concentrations of Rb and Sr. Results obtained from six silicate powders of certified reference materials are in good agreement with recommended values within ±0.002% for the 87Sr/86Sr ratio, ±2% for the 87Rb/86Sr ratio and the Rb and Sr elemental contents. The only exception is JG-1a, with slightly higher 87Rb/86Sr and slightly lower 87Sr/86Sr. This new method improved the analytical efficiency and sample throughput without compromising the analytical accuracy and precision. The filament consumption is reduced by 50% compared with conventional methods and therefore significantly reduces operation costs.

Analysis of the Impact of Physicochemical Parameters Characterizing Coal Mine Waste on the Initialization of Self-Ignition Process with Application of Cluster Analysis

Purpose The subject of the research presented in this paper is the analysis of physicochemical parameters characterizing coal mine waste, in terms of their impact on the initialization of the self-ignition phenomenon. Methods The model was constructed with the application of Hierarchical Cluster Analysis complemented with a colour data map enabling the tracing of similarities between the samples of coal mine waste in the space of parameters and between the examined physicochemical parameters in the space of samples. The data set analysed included parameters characterizing coal mine waste collected from 12 various coal mine waste dumps, either in operation or closed, and where thermal effects either took place or were not reported. Results The HCA model constructed and complemented with a colour data map revealed that the tendency of coal mine waste to self-ignite is primarily affected by the contents of moisture, ash, volatile matter, C and S, values of heat of combustion, calorific value and contents of SiO2, Al2O3, K2O, SO3, TiO2, Co, Ni and Rb. Practical implications One of the major environmental hazards associated with the storage of coal mine waste is the possibility of self-ignition. At present, there are no applicable methods of assessment of this risk. The application of Hierarchical Clustering Analysis complemented with a colour data map enabled the analysis of data structures organized in matrix X(m × n) by tracing the similarities between the examined objects in the parameter space and between the measured parameters in the object space, and therefore contributed to the development of procedures of coal mine waste self-ignition risk assessment. Originality/value The originality of the study presented in this paper comes from finding the parameters affecting the tendency of coal mine waste to self-ignite.

Analysis of the Impact of Physicochemical Parameters Characterizing Coal Mine Waste on the Initialization of Self-Ignition Process with Application of Cluster Analysis

Purpose The subject of the research presented in this paper is the analysis of physicochemical parameters characterizing coal mine waste, in terms of their impact on the initialization of the self-ignition phenomenon. Methods The model was constructed with the application of Hierarchical Cluster Analysis complemented with a colour data map enabling the tracing of similarities between the samples of coal mine waste in the space of parameters and between the examined physicochemical parameters in the space of samples. The data set analysed included parameters characterizing coal mine waste collected from 12 various coal mine waste dumps, either in operation or closed, and where thermal effects either took place or were not reported. Results The HCA model constructed and complemented with a colour data map revealed that the tendency of coal mine waste to self-ignite is primarily affected by the contents of moisture, ash, volatile matter, C and S, values of heat of combustion, calorific value and contents of SiO2, Al2O3, K2O, SO3, TiO2, Co, Ni and Rb. Practical implications One of the major environmental hazards associated with the storage of coal mine waste is the possibility of self-ignition. At present, there are no applicable methods of assessment of this risk. The application of Hierarchical Clustering Analysis complemented with a colour data map enabled the analysis of data structures organized in matrix X(m × n) by tracing the similarities between the examined objects in the parameter space and between the measured parameters in the object space, and therefore contributed to the development of procedures of coal mine waste self-ignition risk assessment. Originality/value The originality of the study presented in this paper comes from finding the parameters affecting the tendency of coal mine waste to self-ignite.

Placental chemical elements concentration in small fetuses and its relationship with Doppler markers of placental function

IntroductionIn this study, we aimed at quantifying placental concentrations of 22 chemical elements in small fetuses (SGA) as compared with normally grown fetuses (AGA), and to assess the relationship with Doppler markers of placental function. MethodsProspective cohort study, including 71 SGA fetuses (estimated fetal weight < 10th percentile) and 96 AGA fetuses (estimated fetal weight > 10th percentile), recruited in the third trimester of gestation. The placental concentration of 22 chemical elements was determined by inductively coupled plasma optical emission spectrophotometer (ICP-OES, ICAP 6500 Duo Thermo): aluminum (Al), beryllium (Be), bismuth (Bi), calcium (Ca), cadmium (Cd), cobalt (Co), chrome (Cr), copper (Cu), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), phosphorus (P), lead (Pb), rubidium (Rb), sulfur (S), strontium (Sr), titanium (Ti), thallium (Tl), antimony (Sb), selenium (Se), and zinc (Zn). Placental function was assessed by measuring the following fetal-maternal parameters: Uterine artery Pulsatility Index (UtA PI), Umbilical artery Pulsatility Index (UA PI) and Middle Cerebral artery Pulsatility Index (MCA PI). The association between the chemical elements concentration and study group and the association with Doppler measures were evaluated. ResultsSGA was associated with significantly (p < 0.05) lower concentrations of Al (AGA 21.14 vs SGA 0.51 mg/kg), Cr (AGA 0.17 vs SGA 0.12 mg/kg), Cu (AGA 0.89 vs SGA 0.81 mg/kg), Mg (AGA 0.007 vs SGA 0.006 g/100g), Mn (AGA 0.60 vs SGA 0.47 mg/kg), Rb (AGA 1.68 vs SGA 1.47 mg/kg), Se (AGA 0.02 vs SGA 0.01 mg/kg), Ti (AGA 0.75 vs SGA 0.05 mg/kg) and Zn (AGA 9.04 vs SGA 8.22 mg/kg). Lower placental concentrations of Al, Cr, Mn, Se, Ti were associated with abnormal UtA, UA and MCA Doppler. DiscussionLower placental concentrations of Al, Cr, Cu, Mn, Rb, Se, Ti and Zn are associated with SGA fetuses and abnormal fetal-maternal Doppler results. Additional studies are required to further understand how chemical elements affect fetal growth and potentially find strategies to prevent SGA.

Spider web biomonitoring: A cost-effective source apportionment approach for urban particulate matter

Elevated levels of particulate matter (PM) in urban atmospheres are one of the major environmental challenges of the Anthropocene. To effectively lower those levels, identification and quantification of sources of PM is required. Biomonitoring methods are helpful tools to tackle this problem but have not been fully established yet. An example is the sampling and subsequent analysis of spider webs to whose adhesive surface dust particles can attach. For a methodical inspection, webs of orb-weaving spiders were sampled repeatedly from 2016 to 2018 at 22 locations in the city of Jena, Germany. Contents of Ag, Al, As, B, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Si, Sn, Sr, Th, Ti, V, Y, Zn and Zr were determined in the samples using inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) after aqua regia digestion.Multivariate statistical methods were applied for a detailed evaluation. A combination of cluster analysis and principal component analysis allows for the clear identification of three main sources in the study area: brake wear from car traffic, abrasion of tram/train tracks and particles of geogenic origin. Quantitative source contributions reveal that high amounts of most of the metals are derived from a combination of brake wear and geogenic particles, the latter of which are likely resuspended by moving vehicles. This emphasizes the importance of non-exhaust particles connected to road traffic.Once a source identification has been performed for an area of interest, classification models can be applied to assess air quality for further samples from within the whole study area, offering a tool for air quality assessment. The general validity of this approach is demonstrated using samples from other locations.