Major Trace Elements Research Articles

Investigating the Effect of Gypsum Powder on Chemical Constituents of Soil and Selected Crops, Adigudem, Tigray, Ethiopia

This paper investigates the effects of gypsum powder from the gypsum plant in Adigudem on chemical properties of soil as well as the yield of two major crops, wheat (Triticum aestivum) and barley (Hordeum vulgare). Three mixes of 10kg of soil with 0%, 10%, 30%, and 50% proportion of gypsum powder were used for pot experiments under glasshouse conditions at Mekelle University. One bulk soil sample was collected from a spot at 4 km from the eastern side of the plant. The chemical concentration of major elements Ca, K, Na, Mg, and Mn, and trace elements, Cd, Zn, Cu, Pb, Cr, and Fe in soil and plant parts were determined using an Atomic absorption spectrometer as well as NO3, PO4 and SO4 using UV-spectrometer. The results suggest that the gypsum powder enhances metals and anion content in soil and in crop parts compared to the control sample. The chemical constituents in soil and crop parts showed negligible variation with increasing proportions of gypsum powder. Gypsum loaded Ca, SO4, Mn, and Pb onto the soil, which exhibited higher Mg, Cu, Mo, Cd, NO3, and PO4 but the comparable concentrations of Fe, K, Zn, and Cr in decreasing order. However, a direct relationship was noted in chemical constituent loadings along the pathway: powder-soil-crop in a similar fashion in the three mixes. Factor analyses revealed that wheat parts have a higher accumulation of nutrients than the barley parts with higher content in its growth soil blends. As an extension of this research, the in-situ investigation is recommended to assess the direct impact of the gypsum powder emitted over the soil and crops.

When did the final closure occur of the eastern Paleo-Asian Ocean: Constraints from the latest Early–Middle Triassic adakitic granites in the southeastern Central Asian Orogenic Belt

There is a broad consensus that the Solonker suture zone marked the final closure of the eastern Paleo-Asian Ocean, which led to the formation of the eastern segment of the Central Asian Orogenic Belt (CAOB). However, when and how the final closure occurred still remained controversial. Located in a key position in the southeastern CAOB, the Early Mesozoic magmatic rocks along the northern margin of the North China Craton provide a crucial window to evaluate the subduction and final closure processes of the eastern Paleo-Asian Ocean. To address these issues, data on geochronological, whole-rock geochemical, whole-rock Sr-Nd and in situ zircon Hf isotopic study of the Early Mesozoic granites, as well as major-trace elements compositions of the apatites are reported here. Zircon U-Pb dating results showed that our studied granites were emplaced in the Middle Triassic (243.1–242.6 Ma). These granites have high Sr (250–652 ppm) contents, low heavy rare earth elements (HREEs), Yb (0.46–0.77 ppm) and Y (4.48–8.15 ppm) contents, and show high Sr/Y and (La/Yb)N signatures (36–108 and 21–35, respectively), with negligibly negative to moderately positive Eu anomalies (δEu = 0.80–1.36), indicating adakite-like affinities. Most of these granite samples are characterized by high K2O contents (3.30–4.83 wt%), and belong to the high-K calc-alkaline and shoshonitic series, with peraluminous affinities (A/CNK = 1.02–1.28). Besides, their low MgO (0.10–0.34 wt%), Cr (0.99–3.50 ppm), and Ni (0.96–2.40 ppm) contents indicate a thickened continent crustal origin, rather than subducting slab-derived or delaminated lower crust-derived melts. Analyzed granite samples yielded in situ zircon εHf (t) values (–8.3 to + 5.8) and whole-rock εNd (t) values (–4.38 to –5.69), with predominately negative values, indicating mixture sources of major recycled old components and limited juvenile crustal materials. Their parental magma was originated by partial melting of thickened lower crust, under garnet amphibolite facies conditions. Thickened crust in the southeastern CAOB yielded crustal thickness of ~54–64 km estimated from (La/Yb)N ratios of these lower crust-derived granites. These constraints, in conjunction with the E-W trending collision-related adakitic granitoids (250–243 Ma) along the southeastern CAOB, and other geological evidence, recorded a tectonic transition from this prolonged subduction to final closure of the eastern Paleo-Asian Ocean.

Reference intervals for trace elements in the general Danish population and their dependence on serum proteins

Reference intervals that indicate the anticipated results of clinical chemistry parameters in a healthy background population are essential for the proper interpretation of laboratory data. In the present study, we analysed major trace elements in blood samples from 400 randomly selected members of the general Danish population. Reference intervals were established for trace elements in both whole blood and serum, and associations with major plasma transport proteins were investigated. In the case of a statistically significant correlation, a corresponding protein-adjusted reference interval was established for comparison with the unadjusted interval. While several trace elements correlated with albumin, ferritin and transferrin, the overall impact of transport proteins was minor and resulted in only marginal changes in the reference intervals. In conclusion, the updated reference intervals for trace elements can be employed without adjusting for plasma protein concentrations.

Comprehensive Automated Thin-Section Characterization Combined with Quantitative Major-Trace Element Analysis on a Single SEM

Comprehensive Automated Thin-Section Characterization Combined with Quantitative Major-Trace Element Analysis on a Single SEM

Recycling of subducted continental crust: Geochemical evidence from syn-exhumation Triassic alkaline mafic rocks of the southern Liaodong Peninsula

Syn-exhumation mafic magmatism during continental collision provides insights into the crust-mantle reaction during deep subduction and the nature of orogenic lithospheric mantle in collisional orogens. In this study, we present a comprehensive data set of zircon U-Pb ages and whole-rock major-trace elements as well as Sr-Nd-Pb isotopes of alkaline mafic rocks from the southern Liaodong Peninsula, eastern China. Zircon U-Pb analyses yield Late Triassic age of 213 ± 3 to 217 ± 3 Ma, younger than the Middle Triassic ultrahigh-pressure metamorphic rocks of the Dabie-Sulu orogen. Thus, the alkaline mafic rocks are products of syn-exhumation magmatism during continental collision of the South and North China blocks. The rocks show shoshonitic affinities with high K2O (3.78–5.23 wt%) and K2O/Na2O (0.71–1.22). They are characterized by arc-like trace-element patterns with enriched LILE, Pb, and LREE, and depleted HFSE. They exhibit enriched Sr-Nd isotopic compositions with high initial 87Sr/86Sr isotopic ratios of 0.7058–0.7061 and negative εNd(t) values of −13.0 to −15.1. These results suggest involvement of recycled continental crust in their mantle source. The mantle source likely formed by the metasomatic reaction of subducted continental crust-derived melts with the overlying subcontinental lithospheric mantle during the Triassic continental collision. Decompressional melting of this metasomatized mantle formed syn-exhumation mafic magmas during the transition from convergent to extensional tectonics in the Late Triassic. Accordingly, mafic rocks from the southern Liaodong Peninsula provide a geochemical record of the subduction and recycling of continental crust into the mantle and melt-mantle reaction induced metasomatism within the orogen.

Geochemistry of Pyritic Mudstones from the Singa Formation, Malaysia: Insights into Gold Potential, Source of Sulfur and Organic Matter

Major trace element analyses, including pyrite chemistry of pyritic mudstones of shallow-marine Singa Formation of Pennsylvanian–Early Permian age have been carried out to assess gold potential, the source of sulfur and organic matter. Regionally, Singa Formation spatially correlates with the Bohorok Formation (Sumatra, Indonesia), the Kaeng Krachang group (Thailand), and the Lebyin group (Burma or Myanmar). In Southeast Asia, this formation is important because it has a record of glacial processes that occurred along the northern margin of Gondwana in the Late Paleozoic age. This study has revealed that mudstones of the Singa Formation, which contain lonestones of glacial origin, deposited under suboxic–oxic conditions in shallow marine environment during Pennsylvanian–Early Permian time. The black mudstones contain total organic carbon which ranges from 0.1 to 0.7 wt.%, and gold content varying from 40 to 62 ppb, making them gold source rocks. This study has revealed diagenetic gold presence in the early pyrite generations (pyrites 1, 2, and 3) in these mudstones with gold content ranging up to 1.6 ppm Au which is indicative of early enrichment of gold. Conversely, late generations of pyrite (pyrites 4, 5, and 6) in these mudstones record low gold content up to 0.5 ppm Au. The δ34S values for pyrite grains range from −24.6‰ to +6.2‰ likely indicate a combination of magmatic and biogenic source of sulfur. Organic carbon isotope composition of the pebbly mudstone samples shows a wide range from −23.9‰ to −5.8‰ indicating a mixed terrestrial and marine source.

Origin of syn-collisional granitoids in the Gangdese orogen: Reworking of the juvenile arc crust and the ancient continental crust

AbstractGranitoids at convergent plate boundaries can be produced either by partial melting of crustal rocks (either continental or oceanic) or by fractional crystallization of mantle-derived mafic magmas. Whereas granitoid formation through partial melting of the continental crust results in reworking of the pre-existing continental crust, granitoid formation through either partial melting of the oceanic crust or fractional crystallization of the mafic magmas leads to growth of the continental crust. This category is primarily based on the radiogenic Nd isotope compositions of crustal rocks; positive εNd(t) values indicate juvenile crust whereas negative εNd(t) values indicate ancient crust. Positive εNd(t) values are common for syn-collisional granitoids in southern Tibet, which leads to the hypothesis that continental collision zones are important sites for the net growth of continental crust. This hypothesis is examined through an integrated study of in situ zircon U-Pb ages and Hf isotopes, whole-rock major trace elements, and Sr-Nd-Hf isotopes as well as mineral O isotopes for felsic igneous rocks of Eocene ages from the Gangdese orogen in southern Tibet. The results show that these rocks can be divided into two groups according to their emplacement ages and geochemical features. The first group is less granitic with lower SiO2 contents of 59.82–64.41 wt%, and it was emplaced at 50–48 Ma in the early Eocene. The second group is more granitic with higher SiO2 contents of 63.93–68.81 wt%, and it was emplaced at 42 Ma in the late Eocene. The early Eocene granitoids exhibit relatively depleted whole-rock Sr-Nd-Hf isotope compositions with low (87Sr/86Sr)i ratios of 0.7044−0.7048, positive εNd(t) values of 0.6−3.9, εHf(t) values of 6.5−10.5, zircon εHf(t) values of 1.6−12.1, and zircon δ18O values of 5.28–6.26‰. These isotopic characteristics are quite similar to those of Late Cretaceous mafic arc igneous rocks in the Gangdese orogen, which indicates their derivation from partial melting of the juvenile mafic arc crust. In comparison, the late Eocene granitoids have relatively lower MgO, Fe2O3, Al2O3, and heavy rare earth element (HREE) contents but higher K2O, Rb, Sr, Th, U, Pb contents, Sr/Y, and (La/Yb)N ratios. They also exhibit more enriched whole-rock Sr-Nd-Hf isotope compositions with high (87Sr/86Sr)i ratios of 0.7070−0.7085, negative εNd(t) values of −5.2 to −3.9 and neutral εHf(t) values of 0.9−2.3, and relatively lower zircon εHf(t) values of −2.8–8.0 and slightly higher zircon δ18O values of 6.25–6.68‰. An integrated interpretation of these geochemical features is that both the juvenile arc crust and the ancient continental crust partially melted to produce the late Eocene granitoids. In this regard, the compositional evolution of syn-collisional granitoids from the early to late Eocene indicates a temporal change of their magma sources from the complete juvenile arc crust to a mixture of the juvenile and ancient crust. In either case, the syn-collisional granitoids in the Gangdese orogen are the reworking products of the pre-existing continental crust. Therefore, they do not contribute to crustal growth in the continental collision zone.

REE mineralization in Siwana peralkaline granite, western India-role of fractional crystallization, hydrothermal remobilization, and feldspar-fluid interaction

Peralkaline granites from the Siwana complex in western India host mineralization of rare earth and other high field strength elements (REE/HFSE). In this study, we use textural relations, major-trace element chemistry and Li-isotope composition of minerals to constrain the magmatic evolution of the granites and the mechanism of hydrothermal REE mineralization. Three facies of peralkaline granites, viz., hypersolvus, transsolvus, and pegmatitic are identified in the Siwana complex. The hypersolvus granites constitute two mineralogical variants: clinopyroxene- and ferrorichterite-bearing. Transsolvus granites contain riebeckite-arfvedsonite and occur as patches/network of dikes in hypersolvus granites. Rayleigh crystal fractionation modelling using incompatible trace element abundances in clinopyroxene and amphibole indicates that the hypersolvus and the transsolvus granites formed after 50-85% and 98% melt crystallization, respectively. Early magmatic clinopyroxenes and ferrorichterites in the hypersolvus granites have fairly heavy δ7Li (+18.5‰ to +20.4‰) suggestive of crystallization from highly evolved magmas. Late magmatic arfvedsonites in the transsolvus granites have even heavier δ7Li (+29.7‰ to +33.8‰). Rayleigh distillation modelling using Li isotopes reveal that the hypersolvus and transsolvus granites crystallized from parental magmas that had undergone >90% fractional crystallization.The Siwana granitoids are hydrothermally altered as evidenced from pseudomorphic re-equilibration of clinopyroxene, alkali feldspar megacrysts, vein and patch perthite formation, replacement of ferrorichterite/clinopyroxene by hydrothermal aegirine, alteration of primary fluorapatite, monazite, aenigmatite, eudialyte, and vlasovite. Three stages of hydrothermal alteration are identified in the granites: stage-I alteration was brought about by highly-saline high-temperature fluid that scavenged REE, HFSE, Ti, Na, and Fe from clinopyroxene and aenigmatite. This was followed by extensive replacement of ferrorichterite and arfvedsonite by aegirine, which decreased the pH and salinity of the fluid. The third stage of alteration led to the replacement of vlasovite by calciocatapleiite, elpidite, and eudialyte and was accompanied by the replacement of alkali feldspar by aegirine, quartz, and secondary REE minerals. The bulk of the REE mineralization occurs in transsolvus granites as cerite associated with aegirine and quartz. Textural relations indicate that these minerals pseudomorph alkali feldspar. Distinct assemblages of secondary REE minerals are identified in the pyroxene- and amphibole-bearing granites-only hydroxyl-dominated REE minerals like cerite are identified in the former while late-stage replacement of cerite by bastnäsite and chevkinite is observed in the latter, the difference controlled by the extent of ferrorichterite to aegirine transformation. The precipitation of secondary REE minerals was largely triggered by pH increase due to the interaction of alkali feldspar with REE-bearing hydrothermal fluids, resulting in the replacement of alkali-feldspar with Fe-phyllosilicates.

A Mechanistic Link Between Selenium and Coronavirus Disease 2019 (COVID-19).

Purpose of ReviewCoronavirus disease 2019 (COVID-19) is a rapidly emerging disease caused by a highly contagious virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and this disease has affected millions of people across the world and led to hundreds of thousands of deaths worldwide. Nutrition is a key factor related to this disease, and nutritional status may determine the risk and outcomes of SARS-CoV-2 infection. Selenium is one of the major trace elements required for redox functions and has significant roles in viral infections. The purpose of this review was to examine the current evidence on the role of selenium in COVID-19. We reviewed studies on selenium and COVID-19, and other relevant studies to understand how selenium status can modify the risk of SARS-CoV-2 infection, and how selenium status might affect a person post-infection.Recent FindingsWe found that oxidative stress is a characteristic feature of COVID-19 disease, which is linked with the immunopathological disorder observed in individuals with severe COVID-19. Selenium plays a key role in strengthening immunity, reducing oxidative stress, preventing viral infections and supporting critical illness. Moreover, selenium deficiency is related to oxidative stress and hyperinflammation seen in critical illness, and selenium deficiency is found to be associated with the severity of COVID-19 disease.SummarySelenium supplementation at an appropriate dose may act as supportive therapy in COVID-19. Future studies in large cohorts of COVID-19 are warranted to verify the benefits of selenium supplementation for reducing risk and severity of COVID-19.

Chau Thoi and Nui Gio volcanic rocks: A remnant of the Loei Phetchabun volcanic belt in Viet Nam

Introduction: Extrusive volcanic rocks, such as dacite, andesite, basalto-andesite, basalt… of Chau Thoi and Nui Gio hills in Bien Hoa and Binh Phuoc provinces, southern Viet Nam, characterize volcanic island arc rocks. These rock suites formed as the convergent tectonic between the Indochina and Sibumasu geological blocks.
 Methods: Geochemical data of rock samples collected on the field were examined and analyzed by the Academia Sinica I E S (Institute of Earth Science, Taiwan and processed with a GCD kit (Geochemical Data Toolkit) to ascertain their characteristics and geotectonic setting. Result: Geochemical data both in major elements and trace elements of the Chau Thoi – Nui Gioshow a specific characteristic of a volcanic island arc environment.
 Discussion: Chau Thoi and Nui Gio rocks are suitable to correlate to the Permian Thailand Loei Phetchabun volcanic belt. However, at the current time, Chau Thoi and Nui Gio rocks have been classified as Deo Bao Loc formation - late Jurassic to early Cretaceous in ages - belong Truong Son magmatic belt. This magmatic belt resulted from the Yanshanian orogeny by the subduction of the Paleo-Pacific oceanic plate beneath the Eurasia (Indochina) continental plate. More studies needed to be performed, specially geochronological data to support the study.
 Conclusion: Chau Thoi and Nui Gio rock suites characterize volcanic island arc rocks, products of a convergence tectonic between Indochina and Sibumasu blocks. They are remnants of the Thailand Loei Phetchabun volcanic belt, the first time reported in Vietnam.

The Cuitzeo granitic xenolith: evidence of an Early Miocene magma plumbing system in central Mexico

Relevant data on the structure and composition of the crystalline basement in Central México can be found by means of plutonic, metamorphic, and sedimentary xenoliths transported by Neogene and Quaternary volcanic eruptions within the Trans-Mexican Volcanic Belt (TMVB). We present detailed major oxide and trace elements concentrations, isotopic analysis and thermobarometric estimations for a granitic xenolith found in an Early Miocene ignimbrite in Cuitzeo Lake, Michoacán. The xenolith is a calc-alkaline quartz-plagioclase-K-feldspar-biotite-amphibole granite-monzogranite with 73.7 wt.% SiO2. Trace element and isotopic signatures are compatible with a volcanic arc signature. According to amphibole-plagioclase pairs and Ti-in-zircon thermobarometry, the studied xenolith suggests that the granitic system crystallized between 655–737 °C and 1.3–1.9 kbar. U-Pb isotopic analyses of zircon grains from this rock have provided a concordia age of 20.76 ± 0.11 Ma. The presence of granitic xenoliths in Quaternary eruptions produced by the TMVB are not rare. However, this is the first zircon age of a Miocene granitic rock showing evidence of the shallow plutonic counterpart of the magma plumbing system of the Early Miocene (~23 to ~16 Ma) Mil Cumbres - Angangueo voluminous, andesitic-dacitic-rhyolitic episode. Implications for faulting, erosion, and Miocene-Pliocene ignimbrite emplacement in Cuitzeo region are also discussed.

Multi-stage garnet formation and destruction in Kimberley harzburgitic xenoliths, South Africa

Thirty-nine garnet harzburgites from Kimberley in the Kaapvaal Craton (South Africa) were studied to constrain the origin, age and evolution of sub-cratonic lithospheric mantle (SCLM). In order to avoid chemical overprinting by recent metasomatism, only garnet harzburgites that appeared clinopyroxene-free to the naked eye were sampled. The majority of garnets were, however, in equilibrium with clinopyroxene (24 of 39). Whole rock and mineral major–trace element geochemistry and garnet Sr–Nd–Hf isotope data are presented. Equilibration pressures range from 3.8–6.1 GPa, indicating the harzburgites were derived from a large portion of the SCLM (~115–185 km). High olivine Mg# (~93.4, n = 39) and low whole rock heavy rare earth elements (HREE) contents are consistent with large degrees of partial melting (>45%) and garnet exhaustion leaving a dunitic residue with olivine ≥90%, orthopyroxene ≤10% and HREE <0.01 times chondrite. Mineral modes, whole rock Al2O3 (0.5–3.2 wt%) and SiO2 (43.1–49.1 wt%), however, indicate heterogeneous re-introduction of garnet (≤13%) and orthopyroxene (≤50%). Harzburgites with high garnet and relatively low orthopyroxene modes (mostly ~7–13% and ~ 9–30%; n = 6) are characterised by mildly sinusoidal garnet REE patterns (Tb-Dy minimum and high HREE) and Archaean depleted Hf TDM ages (2.7–3.3 Ga; εHfe: +190 to +709). In contrast, harzburgites with high orthopyroxene and relatively low garnet and modes (~1.5–7.5% and ~ 25–50%; n = 19) are characterised by highly sinuous REE patterns (Ho-Yb minimum and low HREE) and Proterozoic enriched Hf TDM ages (0.7–1.6 Ga; εHfe: −16 to +6). It is inferred that Archaean G10 garnet re-introduction caused a significant increase in HREE, making melt depletion models based on HREE inaccurate. Orthopyroxene addition, a few hundred million years later, most likely at ~2.7 Ga and associated with Ventersdorp magmatic activity, caused partial consumption of garnet and olivine, and changed garnet compositions leading to: 1) Cr/Al ratio increase; 2) HREE decrease; 3) more sinusoidal REE patterns; and 4) un-radiogenic 176Hf/177Hf. Garnets define a Lu-Hf isochron age of 2702 ± 64 Ma (εHfi = +44, n = 31), which is interpreted as a consequence of partial isotopic equilibrium within the SCLM and mixing of the garnet- and orthopyroxene-rich metasomatic components. The low LILE contents and absence of Nb-Ta anomalies are consistent with modal metasomatism caused by intra-plate magmatism. In addition, the REE signatures of metasomatic agents in equilibrium with the garnets suggest that carbonatitic melts and SiO2-rich hydrous melts were responsible for re-introduction of garnet and orthopyroxene, respectively. Sr-Nd isotope systematics were disrupted associated with kimberlite magmatism (Nd isochron: 217 ± 58 Ma, εNdi = +4; n = 34), consistent with recent G10 garnet transformation into G9 garnets (Ca + Fe-enriched). This event may have caused garnet addition (up to 1%), suggesting that garnet was formed or destroyed in at least 4 different events: i) initial extensive polybaric melting, ii) asthenospheric melts re-introducing the bulk of the garnet, iii) orthopyroxene addition and garnet loss, all in the Archaean, and iv) minor garnet addition possibly related to recent kimberlite magmatism prior to eruption.

Source diversity in controlling the compositional diversity of Cenozoic granites in the Tethyan Himalaya

Cenozoic granites in the Himalayan orogen show compositional diversity. Yet the importance of source diversity in causing the compositional diversity is underestimated. Here we studied whole-rock Sr–Nd isotope geochemistry and relict zircon U–Pb geochronology of three suites of granites in the Himalayan orogen. Combing our new data and previous data, a new source component, namely metasedimentary rocks from the Triassic Langjiexue Group in the Tethyan Himalaya, was identified. Such a component is characterized by 200–400 Ma-aged zircons and relatively less enriched Sr–Nd isotopic compositions. These signatures have been imprinted on both the Eocene and Miocene granites from the Yalaxiangbo area. As a comparison, geochemical features and relict zircon U–Pb age spectrum of the Miocene Cuona granites both suggested they were derived from partial melting of metapelites of the Higher Himalayan Sequence. Phase equilibrium modeling results suggest that both the Langjiexue metapelite and the Higher Himalayan metapelite have comparable fertility. Given their similar lithology and major-trace element compositions, the resultant melts will have no significant distinction in lithochemistry. This explains why many reported granites in the Tethyan Himalaya have undistinguishable major-trace elemental compositions to the Higher Himalayan leucogranites, but have less enriched Sr–Nd isotopic compositions. However, if metamafic rocks were involved, the resultant melts will depart from the Higher Himalayan leucogranites in both elemental and isotopic compositions, exemplified by the Miocene adakites in the Tethyan Himalaya. This study highlights the importance of source diversity in causing the compositional diversity of the Cenozoic granites in the Tethyan Himalaya.

Geochemical Distinction Between Altered Oceanic Basalt- and Seafloor Sediment-Derived Fluids in the Mantle Source of Mafic Igneous Rocks in Southwestern Tianshan, Western China

AbstractThe role of subducting oceanic crust-derived fluids in generating mafic arc magmatism has been widely documented. However, the subducting oceanic crust is generally composed of basaltic igneous crust and seafloor sediment, which may give rise to different compositions of liquid phases causing metasomatism of the mantle wedge. Because of the similarity in enrichment of fluid-mobile incompatible elements in the two sources of subduction zone fluids, it has been a challenge to distinguish between them when studying the products of mafic arc magmatism. This difficulty is overcome by a combined study of whole-rock Li isotopes and zircon O isotopes in addition to whole-rock major-trace elements and Sr–Nd–Hf isotopes in Late Paleozoic mafic igneous rocks from southwestern Tianshan in western China. Zircon U–Pb dating yields consistent ages of 313 ± 3 Ma to 305 ± 1 Ma for magma crystallization. The mafic igneous rocks exhibit arc-like trace element distribution patterns and depleted whole-rock Nd–Hf isotopes but slightly high (87Sr/86Sr)i ratios of 0·7039– 0·7057. They also show positive zircon εHf(t) values and slightly higher zircon δ18O values of 5·2–7·6‰. There are covariations of whole-rock Sr isotopes with Th/La and Rb/Nb ratios, indicating a contribution from terrigenous sediment-derived fluids to their mantle source in addition to basaltic igneous crust-derived fluids. Based on the slightly higher zircon δ18O values but variably lower whole-rock δ7Li values of -0·8 to 3·5‰ for the target rocks than those of mantle respectively, both altered oceanic basalt- and terrigenous sediment-derived fluids are identified in the mantle source of these mafic igneous rocks. Model calculations for trace elements and Sr–Nd–Li isotopes further confirm that the geochemical compositions of these mafic igneous rocks can be explained by chemical reaction of depleted MORB mantle peridotite with the mixed fluids to generate ultramafic metasomatites at subarc depths. Therefore, chemical metasomatism of the mantle wedge is a key mechanism for the incorporation of crustal components into the source of arc-like mafic igneous rocks above oceanic subduction zones.

Trace element mass fractions in road dust as a function of distance from road

ABSTRACT Road dust particles play an important role in atmospheric pollution and are associated with adverse human health effects. Traffic emissions are a major source of particles in road dust. However, there has been limited information about the relationship between distance from road and traffic-related elements levels in road dust. We investigated the relationships between proximity to the nearest major roadway and trace element mass fractions in PM10 and PM2.5 re-suspended from the road surface, based on measurements at three different distance ranges. We found that mass fractions of Ba, Cu, Zr, Zn, Cl, Co, Cr, Ca, Ti in PM10 road dust as well as Zr, Cu, Cl, Zn, Cr, Ti, Mn, Ca, Ni, and Fe in PM2.5 road dust, significantly decreased with distance from major road. Most of these elements are associated with road traffic emissions, including both tailpipe and non-tailpipe emissions. The decrease rates differed among elements due to differences in local traffic contributions. The decreases for elements which are mainly associated with non-tailpipe traffic emissions (e.g., Ba, Zr) were more dramatic. Our results indicate that traffic emissions, especially non-tailpipe emissions, contribute substantially to road dust, suggesting the need for control strategies for non-tailpipe emissions. Implications: We investigated the relationships between road proximity with trace element mass fractions in PM10 and PM2.5 re-suspended from the road surface. We observed significant decrease of traffic-related elements in PM10 and PM2.5 road dust with log distance from major road. We also found that the mass fractions for elements, which mainly come from traffic decrease more sharply compared to elements which come from both traffic and other sources. Our results indicate that traffic emissions contribute substantially to road dust, and imply that the distance to major road can be used as a proxy for ambient exposure.

Geology and petrogenesis of the Sungun deposits: Implications for the genesis of porphyry-type mineralisation in the NW Urumieh–Dokhtar magmatic Arc, Iran

The Miocene Sungun porphyry Cu–Mo systems, located in Azerbaijan belt, NW Iran, is associated with the high-Sr/Y magmas, which were engendered in a post-collisional setting. However, the petrogenesis of these fertile magmas and their mineralisation are still unknown. In this study, we present whole-rock major-trace elements, zircon U–Pb dating and the Lu–Hf isotopes in the ore-forming porphyries of the Sungun porphyry systems. The corresponding results showed that the samples were rich in large-ion lithophile elements and poor in high-field-strength elements; moreover, they presented both high K2O (2.4–3.5 wt%) and Sr (727–770 ppm) and low Y (11–14 ppm) contents. The zircon U–Pb age of the Sungun porphyry was ~19 Ma, with positive εHf(t) ratios (5.5–11.8) and young TDM2 ages between 322 and 705 Ma. Additionally, the Sungun high-Sr/Y porphyries contained anhydrites (CaSO4); and had high zircon Ce4+/Ce3+ ratios (33–728), relatively low zircon saturation temperatures (620–804 °C), and plagioclases with excess Al content. Overall, these evidences suggest that a water-fluxed melting of the subduction-modified juvenile lower crust might have generated a high oxygen fugacity, leading to the formation of the hydrous and S-rich Sungun fertile magmas in the NW Urumieh–Dokhtar magmatic Arc.

Multi-method geochemical characterization of groundwater from a hypogene karst system

An approach, combining several geochemical methods, was used to determine the groundwater properties and components of a hypogene karst system, where sampling is restricted only to the spring sites, and with a limited number of available sampling locations. Radiogenic isotopes (3H, 14C) were used to constrain the groundwater mean residence time and separate different groundwater components. Noble gases, stable isotopes of water (δ18O, δ2H), dissolved inorganic carbon (δ13C) and dissolved sulfate (δ34S, δ18O), and major ion and trace element composition were used to identify the source of water, its chemical evolution and water–rock interactions, as well as to identify the contribution and composition of endogenic gases. This approach was applied to three low-temperature thermal springs located in Mariovo (North Macedonia) associated with fossil hypogene caves, previously identified by morphological and geochemical studies of caves and cave deposits. Based on the obtained results, the main studied springs represent an output part of a regional hypogene karst groundwater system with a deep-circulating (~1 km), old (~15 ka), thermal (≥60 °C) water, which mixes with young (<50 years), cold (<14 °C) and shallow epigene karst groundwater. The output parts are structurally controlled, at the interception of low topography and deep faults, along which the groundwater interacts with deep-seated gases, dominantly CO2 of metamorphic origin (δ13C of +4.5‰ VPDB), with some contribution of mantle helium. The thermal karst groundwater interacts at depth with volcanic rocks from the nearby Neogene-Quaternary volcanic complex, as well as with metamorphic basement rocks and granitoids.

Sedimentological and Geochemical Charectesization of Manaveli and Cuddalore Formations, Puducherry Basin, India

Sedimentological and Geochemical Charectesization of Manaveli and Cuddalore Formations, Puducherry Basin, India &#x0D; &#x0D; Shyam N. Mude, Shyam Yawale and Vishal Choudhari &#x0D; &#x0D; Department of Geology, Fergusson College (Autonomous), Pune- 411004, India&#x0D; Email: shyam.mude@fergusson.edu; shyammude25@yahoo.co.in&#x0D; &#x0D; Abstract: The lithostratigraphically rocks of Puducherry basin (Sub-basin of Cauvery Basin) have been classified as Valudavur, Mettuveli, Karasur, Manaveli, Cuddalore formations in ascending order of deposition. The sedimentological and geochemical studies of sediments from Manavali (Paleocene) and Cuddalore (Mio-Pliocene) formations were carried out to understand grain size variation and distribution of major oxides and trace elements. &#x0D; The sieve analysis was used to study grain size variation and on the basis of grain sizes various geo-statistical parameters were calculated to understand depositional environment. The discriminant function analysis of the sediments from the Cuddalore Formation infers that mostly the sedimentation was occurred in fluvio-deltaic environment with incursions of shallow marine environment whereas bivariate plots suggests that the deposition was occurred in riverine to deltaic environment.&#x0D; The major element geochemistry of the Manaveli and Cuddalore formations have been carried out to understand the provenance, paleoclimate and source area weathering conditions. The values of CIA (Chemical Index of Alteration), CIW (Chemical Index of Weathering), ICV (Index of Compositional Variability) and PIA (Plagioclase Index of Alteration) of the sediments infer high weathering was occurred in source area of sediments for Manaveli and Cuddalore formations. The ratio (Al2O3+K2O+Na2O)/SiO2 indicate semi-humid climatic conditions during deposition of Cuddalore Formation whereas Manaveli Formation was deposited in semi-arid climatic conditions. The discriminant function diagram (A-CN-K Plot), suggest Quartzose sedimentary provenance for Cuddalore and Mafic igneous provenance for Manaveli Formation. &#x0D; &#x0D; Keywords: Grain Size, Geochemistry, Manaveli, Cuddalore, Puducherry Basin

Major-trace element and Sr-Nd isotope compositions of mafic dykes of the Singhbhum Craton: Insights into evolution of the lithospheric mantle

The Singhbhum Craton in eastern India is host to at least seven sets of mafic dyke swarms. Four previously dated swarms (studied here) include the NNE-trending Keshargaria (ca. 2.80 Ga) and Ghatgaon (ca. 2.76 - 2.75 Ga) swarms, the ENE-trending Kaptipada swarm (ca. 2.26 Ga), and the ESE-trending Pipilia swarm (ca.1.76 Ga). The dykes range in composition from basalt to andesite and have transitional tholeiitic to calc-alkaline affinities. They show intra- and inter-swarm geochemical and Sr-Nd isotopic heterogeneities and have SiO2 content ranging from 47 to 60 wt.%. The chondrite normalized REE patterns show enrichment in LREE and the Primitive-Mantle normalized multi-element patterns show elevated U, Th, Cs, Rb, K, and Pb; and depletion in Nb, Ta, and Ti. These characteristics indicate involvement of crustal component in the petrogenesis of these dykes. The dykes of different swarms have variable 87Sr/86Sri and εNd(i) values, which define a crust-like isotopic growth trajectory with time from a common chondritic to depleted source that was enriched contemporaneously with the formation of the crustal rocks of the Singhbhum Craton. The isotope data indicate involvement of older enriched crustal material in the petrogenesis of these dykes. Variable but mostly high (compared to similarly evolved magmas) Ni (40 - 590 ppm), Cr (40 - 1110 ppm), and V (120 - 434 ppm) contents particularly of the most primitive dykes indicate that parental melts were in equilibrium with mantle peridotite and experienced only minor fractional crystallization of olivine, pyroxene, and magnetite. The Sr-Nd isotope ratios do not show any correlation with differentiation indices which indicates that the melts were not modified significantly by crustal assimilation during ascent and emplacement. The crust-like secular trend of the Sr and Nd isotopic compositions suggests that the enriched crustal material was incubated in the mantle (i.e., metasomatized lithospheric mantle) for a long time and this source was periodically tapped leading to multiple dyke emplacement events over at least 1 Gyr. The recycled crustal material played a role in metasomatizing the subcontinental lithospheric mantle prior to ca. 2.80 Ga. Mantle plume activity triggered melting of the metasomatized lithospheric mantle many times, leading to the emplacement of mafic dykes of different generations across the craton.

Evaluation of Major Minerals and Trace Elements in Wild and Domesticated Edible Herbs Traditionally Used in the Mediterranean Area

The human diet is characterized by the intake of major minerals (Na, K, Ca, Mg, P, N) and trace elements (Zn, Mn, Se, Cu, Fe, Co, I, Cr, F, Pb, Cd) for their key role in many metabolic functions. Nowadays, the research of sources able to improve their intake is in continuous evolution, especially in the undeveloped countries. In this sense, wild edible herbs, commonly used since ancient times, can represent a good alternative to improve the daily human intake of minerals. In this study, four wild edible species, Rumex acetosa, Picris hieracioides, Cichorium intybus, and Plantago coronopus, were analyzed for their content in Na, K, Ca, Mg, Cu, Mn, Fe, and Zn and, besides, three domestications (named “soilless,” pot, and open field) were evaluated in the analyzed species in the prospective of their commercialization as valuable sources of minerals in the human diet. Nitrate and oxalate contents were also evaluated, given their negative impact on human health. Results unveil that open field domestication allowed the plants to maintain the content of major minerals similar to those measured in wild plants, especially in C. intybus and P. hieracioides. The trace elements Cu, Mn, Fe, and Zn were not recorded at high content irrespectively to the wild collection or domestications. Finally, plants grown in the open field also accounted for a high oxalate and nitrate content, especially in R. acetosa. Further researches should be aimed at decreasing the oxalate and nitrate content in the domesticated species and to promote the commercialization of the domesticated species.