Study Of Trace Elements Research Articles

The blue road: Provenance study of azurite samples from historical locations through the analysis of minor and trace elements

The pigments used by artists since ancient times play an important role in historical, artistic, and cultural investigations. They allow the acquisition of useful information for the study of human and technological development. This research aims at differentiating the various sources of azurite exploited in antiquity, based on the study of minor and trace elements. Azurite is one of the most important blue pigments in art history, widely used during the Middle Age and Renaissance. However, very few studies investigated the provenance of the pigment, so today it is still not possible to clearly identify the sources of azurite exploited in the past. This study is based on the analysis of several samples of azurite belonging to the MUST collection (Museum of Earth Sciences, Sapienza University of Rome, Italy) and coming from different historical localities: UK, Italy, Germany, France, Romania and Slovakia (both representative of the resources within the ancient Kingdom of Hungary), Greece and Russia. The samples were analysed by electron microscopy (EMPA and SEM-EDX) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), with the aim of detecting chemical features that are specific to the different azurite ore deposits.Among the trace elements analysed, Zn, As, Sn, Ca and Sr prove the most suitable for discriminating the origin of the samples, as well as rare earth elements. In particular, Ce and Eu anomalies are suggested as markers for the German and Hungarian localities.

Evidence for Extrusive Mg‐Suite Magmatism on the Moon? Fine‐Grained Magnesian Clasts in an Apollo 16 Impact Melt Breccia

AbstractThe magnesian suite (Mg‐suite) of rocks record some of the earliest intrusive magmatism on the Moon. Studies of these Mg‐suite rocks find they are plutonic or hypabyssal, formed typically kilometers under the lunar surface. Several models exist to explain the formation and evolution of the Mg‐suite but distinguishing between hypotheses can be difficult given the limited sample availability. The global extent of Mg‐suite magmatism remains in debate and is key to constraining models of early secondary crust building. In this study, we present magnesian clasts within Apollo impact melt rock 68815. These clasts contain olivine, plagioclase, with minor amounts of Mg‐Al‐spinel and pyroxene similar to spinel troctolites of the Mg‐suite, but they lack plutonic textures. We provide evidence that some of the clasts may be of extrusive volcanic origin akin to terrestrial komatiites while others might represent crystalline impact melts. There exists a large breadth of evidence for Mg‐suite intrusives, whereas here, we present possible evidence of Mg‐rich volcanic counterparts. If valid, this would broaden the known diversity of lunar volcanism during the initial stages of secondary crust building. We anticipate this finding to provide a greater constraint onto models of Mg‐suite ascent and emplacement, which only currently consider intrusive magmatism, as well as renewed motivation to examine impact melt breccias for rare and understudied lithologies. Future trace element studies or radiometric dating could be used to further interrogate the connections of these clasts to the Mg‐suite.

Size-segregated source identification of water-soluble and water-insoluble metals and trace elements of coarse and fine PM in central Los Angeles

In this study, the water-solubility and sources of metals and trace elements in both fine and coarse particulate matter (PM) were investigated in Central Los Angeles. Sampling was performed in the winter, spring, and summer of 2022 at the Particle Instrumentation Unit (PIU) of the University of Southern California located in the proximity of I-110 freeway. Both fine and coarse PM samples were collected using Personal Cascade Impactors (PCIS) and chemically analyzed to determine their water-soluble and water-insoluble metal content. Principal Component Analysis (PCA) and Multiple Linear Regression (MLR) were used to determine the sources of soluble and insoluble metals and obtain their contributions to total metal concentration. Our results indicate that the water-solubility of most of the metals is higher in the fine size fraction compared to the coarse fraction. Seasonal variations in the water solubility of selected metals for both coarse and fine fractions were observed, with higher water-soluble metal concentrations in summer for several species (e.g., Fe, S, Pb, Cu, La, Ni, and Al), possibly due to higher photochemical processing, while in winter, almost all species exhibited higher insoluble fraction concentrations. The PCA and MLR analyses results showed that tire and brake wear was the most significant contributor to the total metals for both fine soluble and insoluble portions, accounting for 35% and 75% of the total metals, respectively. Combustion sources also contributed substantially to water-soluble metals for fine and coarse size ranges, representing 40% and 32% of the total metal mass, respectively. In addition, mineral dust and soil and re-suspended dust were identified as the highest contributors to coarse metals. The MLR analysis also revealed that secondary aerosols contributed 11% to the fine water-soluble metals. Our results suggest that non-tailpipe emissions significantly contribute to both coarse and fine PM metals in the Central Los Angeles region.

Comparative Analysis of Metabolic Compositions and Trace Elements of Ornithogalum caudatum with Different Growth Years.

As a traditional medicine with extensive history, Ornithogalum caudatum has high nutritional and medicinal value. However, its quality evaluation criteria are insufficient because it is not included in the pharmacopeia. Simultaneously, it is a perennial plant, and the medicinal ingredients change with the growth years. Currently, studies on the synthesis and accumulation of metabolites and elements in O. caudatum during different growth years are unavailable. To address this issue, in this study, the 8 main active substances, metabolism profiles, and 12 trace elements of O. caudatum from different growth years (1, 3, and 5 years old) were analyzed. The main substances of O. caudatum changed significantly in different years of growth. Saponin and sterol contents increased with age; however, the polysaccharide content decreased. For metabolism profiling, ultrahigh-performance liquid chromatography tandem mass spectrometry was performed. Among the three groups, 156 differential metabolites with variable importance in projection values >1.0 and p < 0.05 were identified. Among the differential metabolites, 16 increased with increasing years of growth and have the potential to become age-identified markers. A trace element study showed that the contents of K, Ca, and Mg were higher, and the ratio of Zn/Cu was less than 0.1%. Heavy metal ions in O. caudatum did not increase with age. The results of this study provide a basis to evaluate the edible values of O. caudatum and facilitate further exploitation.

Open-system differentiation of mafic magmas before the formation of layered Fe-Ti(V) deposits in Southeast China

Mafic magmatic differentiation is an important mechanism to drive Fe-Ti enrichments in melt and final formation of layered Fe-Ti-(V) oxide deposits, but how the differentiation operates and how the state of magmatic reservoirs controls differential metallogenic potential are unclear. The Xialan magmatic complex in northern Guangdong Province is the only complex hosting layered Fe-Ti (V) deposits in Southeast China and the formation of such oxide deposits is not addressed in detail. Here, we present an integrated study of geochronology, mineral geochemistry, whole-rock major and trace elements, as well as Sr-Nd-Pb isotopes, on the mafic rocks associated with the Xialan layered Fe-Ti (V) oxide deposits. The investigated mafic rocks are cogenetic and can be classified into three types according to field and textural features: diabase, Fe-Ti rich gabbro, and Fe-Ti barren gabbro. Based on petrographic observation and major and trace element geochemistry, the gabbros and diabases represent cumulates and residual melts, respectively. However, the Fe-Ti rich gabbros show different Nd isotopes from the other rocks, which indicates an open-system differentiation for the Xialan parental magma. A two-stage evolution process for the Xialan parental magma before the final crystallization fractionation to form the oxide deposits is further proposed based on MELTs modeling results and the characters of mineral assemblages. At the early stage, the magmas started differentiation with 0.5 wt% initial H2O content and moderate oxygen fugacity (△FMQ = ca. + 0.5 – +1.5) at 5 kbar and generated Fe-Ti enriched melts. At the later stage, the Fe-Ti rich melts gradually evolved to a much higher H2O content (>3 wt%), which stabilized the Fe-Ti oxides and hornblendes. Wall-rock assimilation during the late-stage magma evolution is suggested to be the key factor to elevate the H2O contents and oxygen fugacity of the magma which finally produced the layered Fe-Ti oxides. As such, this study demonstrates that open-system differentiation of mafic magmas can play a key role in the final generation of some hornblende-bearing layered Fe-Ti oxide deposits.

Metallogenesis and Formation of the Maliping Pb-Zn Deposit in Northeastern Yunnan: Constraints from H-O Isotopes, Fluid Inclusions, and Trace Elements

The Maliping large-scale Pb-Zn deposit is located in the Sichuan-Yunnan-Guizhou Pb-Zn polymetallic metallogenic triangle area (SYGT), where the Pb-Zn ore body is hosted in the interlayer fracture zone at the interface between siliceous cataclastic dolomite and clastic rocks in the Lower Cambrian Yuhuchun Formation and is tectonically driven. Unlike other Pb-Zn de-posits hosted in the Sinian and Carboniferous carbonate rocks in the area, the metallogenic mechanism and deep and peripheral ore prospecting prediction research require further exploration. In this study, representative samples of a typical orebody profile were systematically collected, and microthermometry of fluid inclusions and H-O isotopes and metal sulfide trace element analyses were performed. The main findings were as follows: (1) The fluid inclusion study showed that the ore-forming fluids have vapor-rich phase reduction characteristics of medium-low temperature, salinity, and density. (2) H-O isotopic studies showed that the ore-forming fluids are derived from the mixing of deep-source fluids flowing through the deep fold basement (Kunyang Group) and or-ganic-containing basin brine. (3) Rare earth element (REE) characteristics indicate that the ore-forming materials were primarily derived from the folded basement (Kunyang Group). (4) The trace element study showed that sphalerite is relatively enriched in Cu, Cd, Ga, and Ge, while depleted in Fe, Mn, Sn, and Co, similar to the typical Huize-type (HZT) Pb-Zn deposit in the area. Therefore, it is suitable to explore the deposit using a large-scale “four step style” ore prospecting method for ore prospecting and prediction. Moreover, the results provide a reference for the study of Pb-Zn metallogenic systems and new ideas for the deep and peripheral prospecting of Pb-Zn deposits in this area.

In Situ Trace Element and Fe-O Isotope Studies on Magnetite of the Iron-Oxide Ores from the Takab Region, North Western Iran: Implications for Ore Genesis

The early Cambrian Takab iron ore deposit is situated in the northern part of the Sanandaj-Sirjan zone, western Iran. It consists of banded, nodular and disseminated magnetite hosted in folded micaschists. Trace element and Fe and O isotopic experiments reveal various hydrothermal precipitation environments under reduced to slightly oxidizing conditions. Disseminated magnetite has high Ti (945–1940 ppm) positively correlated with Mg + Al + Si, and heavy Fe (+0.76 to +1.86‰) and O (+1.0 to +4.07‰) isotopic compositions that support a magmatic/high-T hydrothermal origin. Banded magnetite has low Ti (15−200 ppm), V (≤100 ppm), Si and Mg (mostly ≤300 ppm) and variable Al. The ∂56Fe values vary from −0.2‰ to +1.12‰ but most values also support a magmatic/high-T hydrothermal origin. However, variable ∂18O (−2.52 to +1.22‰) values provide evidence of re-equilibration with lower-T fluid at ~200–300 °C. Nodular magnetite shows high Mn (≤1%), and mostly negative ∂56Fe values (average, −0.3‰) indicative of precipitation from an isotopically light hydrothermal fluid. Re-equilibration with carbonated rocks/fluids likely results in a negative Ce anomaly and higher ∂18O (average, +6.30‰). The Takab iron ore deposit has, thus, experienced a complex hydrothermal history.

Fingerprinting crustal anatexis with apatite trace element, halogen, and Sr isotope data

The geochemistry of apatite is a valuable tool for granite petrogenetic study. Here we explore the capability of apatite for fingerprinting anatectic reactions during crustal melting. We conducted a detailed petrographic, trace element, volatile, and Sr isotopic study of the apatites from four groups of leucosomes and leucogranites that formed by amphibole dehydration melting (group I), hydration melting (group II), muscovite dehydration melting (group III), and feldspar accumulation (Group IV) from the central Himalayan orogen. The coexistence of primary CO2-rich fluid and multiphase solid inclusions in apatite indicates fluid–melt immiscibility and suggests that C–O–H fluids were present during hydration melting. We observe marked differences in major and trace element, as well as halogen (F and Cl) contents in apatite from different groups, corresponding to different melting reactions. Apatite REE, Y, Mn, F, and F/Cl exhibit a decrease, whereas Sr/Y and Cl increase, from muscovite dehydration melting to hydration melting, and to amphibole dehydration melting. Amphibole dehydration melting results in similar CaO, Sr, and Eu/Eu* in apatite to hydration melting, but the latter leads to lower (La/Yb)N in apatite. These geochemical differences in apatite can be explained by different minerals participating in the melting reactions and varying melt polymerization resulting from the different melting reactions. The degree of melt polymerization decreases in the sequence from muscovite dehydration melting to hydration melting, and to amphibole dehydration melting. A higher degree of melt polymerization results in higher values for trace element partition coefficients between apatite and melt, and therefore the enhanced incorporation of REE, Y and Mn in apatite. Higher Sr and Eu/Eu* in apatite reflect the consumption of a larger amount of plagioclase in the melting reaction. The F and Cl contents in partial melts were calculated based on apatite composition, which exhibit an increasing trend from hydration melting to muscovite hydration melting, and to amphibole hydration melting. Such a trend can be explained by different proportions of hydrous minerals (muscovite and amphibole) participating in the melting reactions, with amphibole responsible for the high Cl content in melt and apatite. In addition, the apatite Sr isotopic compositions record the Sr isotopic disequilibrium during partial melting and exhibit distinct evolutional trends resulting from different anatectic reactions. Muscovite dehydration melting forms melt with higher 87Sr/86Sr than the restite due to radiogenic Sr released by muscovite. Apatite therefore records progressively decreasing 87Sr/86Sr during melt evolution before the isotopic homogenization between the partial melt and the restite. In contrast, apatites crystallized from the melt of hydration melting show an evolutional trend of increasing 87Sr/86Sr. In summary, the elemental and isotopic compositions of apatite can be related to different types of melting reactions, and can therefore be used as an indicator of the mechanisms of melt formation during crustal anatexis. We demonstrate such an application through the case study of group IV apatite from feldspar accumulation, and also explore its utility in granite petrogenetic studies.

The petrogenetic relationship between migmatite and granite in the Himalayan orogen: Petrological and geochemical constraints

Partial melting of crustal rocks contributes to the formation of granites in collisional orogens. It is generally recognized that residual granulites are compositionally complementary to crustal-derived granites, yet the petrogenetic relationship between migmatites and granites remains obscure. To shed light on this issue, a comprehensive study of field geology, petrographic observations, whole-rock major and trace elements, mineral major elements, zircon and monazite U–Th–Pb isotopes and trace elements, and monazite SmNd isotopes was carried out for the Higher Himalayan leucosomes, leucocratic dikes, and leucogranites from the Cona area in eastern Himalaya. These rocks were formed by partial melting of the Higher Himalayan metasedimentary rocks and granitic gneisses in the Miocene, and are characterized by distinct petrological and geochemical features. Leucosomes and leucocratic dikes, which were derived from different source rocks (granitic gneisses and metasedimentary rocks, respectively), share many similarities. Both of them are rich in K-feldspar and have high K2O, Ba, and Sr contents and CaO/(CaO + Na2O) ratios, but low Rb/Sr and Sm/Nd ratios; LREE contents correlate positively with Th contents, but negatively with P2O5 contents; zircon and monazite have low MREE/HREE ratios. In contrast, leucogranites, which originated from mixed sources of metasedimentary rocks and granitic gneisses, are rich in plagioclase and have low K2O, Ba, and Sr contents and CaO/(CaO + Na2O) ratios, but high Rb/Sr and Sm/Nd ratios; LREE contents correlate positively with Th and P2O5 contents; zircon and monazite have high MREE/HREE ratios. The K2O-rich leucosomes and leucocratic dikes and the Na2O-rich leucogranites do not show geochemical signatures indicative of a link owing to melt evolution processes, suggesting that the two main groups are the products of distinct and independent anatectic processes in the source. The leucosomes and leucocratic dikes are associated with water-fluxed (hydration) melting at lower temperatures and pressures, whereas the leucogranites are related to water-absent (dehydration) melting at higher temperatures and pressures. In this regard, the leucosomes and leucocratic dikes in migmatites and the leucogranites likely represent two different types of anatectic products, which were respectively derived from partial meltig of the hydrated crustal rocks at the shallower level and the dehydrated crustal rocks at the deeper level. The hydrated-dehydrated crustal architecture is ascribed to the influx of water into the shallower crustal rocks caused by metamorphic dehydration at the deeper crustal level. The spatiotemporally coupled dehydration-hydration anatectic processes may be a common mechanism for the formation of coherent granite, migmatite, and granulite in collisional orogens.

Разработка Листвянского, Бугульдейского и Ольхон-Приольхонского мониторинговых полигонов на Байкале: обзорное изучение микроэлементов и изотопов U в речных и подземных водах

The results of prospecting studies of trace elements and activity ratio 234U/238U (АR4/8) in surface waters and groundwaters from the Listvyanka, Buguldeyka, and Olkhon-Priolkhonye polygons of integrated monitoring, organized since 2020, are presented. At the Listvyanka polygon, wide interval of АR4/8 from 1.67 to 2.5 is obtained for groundwater in the Bolshie Koty village, at the Buguldeyka and Olkhon-Priolkhonye polygons that are located in the zone of the Primorsky fault – an interval of AR4/8 from 1.25 to 2.70. These values is general characteristic of large active faults of the central Baikal Rift Zone. Water from the Buguldeyka River differs in terms of both trace element compositions and AR4/8 values from those of its tributary Kurtun due to location of these rivers basins in rocks of the exposed basement of the Siberian Platform and its sedimentary cover, including evaporate carbonate sediments. On the Olkhon island, determined is groundwater that differs in elemental composition from the deep Baikal water.

Study of Various Oxidants and Trace Elements in Cervical Cancer Patients at Tertiary Care Center of Udaipur, Rajasthan, India

Study of Various Oxidants and Trace Elements in Cervical Cancer Patients at Tertiary Care Center of Udaipur, Rajasthan, India

Tracing high-pressure metamorphism in the eastern Himalayan syntaxis using detrital zircon and monazite from modern stream sediments

The timing of high-pressure (HP) metamorphism in the eastern Himalayan syntaxis is important for understanding the India-Asia collisional processes, but it remains elusive. To reveal the metamorphic history of the eastern Himalayan syntaxis, we performed a study of geochronology, trace elements, and mineral inclusions of detrital zircon and monazite from modern stream sediments in the eastern Himalayan syntaxis. Detrital zircon comprise magmatic and metamorphic domains with different zoning. Inherited magmatic zircon domains have high Th/U, low (Dy/Yb)N, and retain ages of 1798−360 Ma. Metamorphic zircon domains with low Th/U, high (Dy/Yb)N, and inclusions of garnet, kyanite, and/or clinopyroxene probably formed under HP conditions. They yield age groups of 49−35 Ma, 33−17 Ma, and 12−7 Ma. The low Th/U and low (Dy/Yb)N metamorphic zircon domains probably formed during retrogression and yield age groups of 27−16 Ma and 10−6 Ma. Detrital monazite yield age distributions similar to those of the low (Dy/Yb)N metamorphic zircon except for the 821−402 Ma inherited cores. The (Dy/Yb)N of 31.6−5.7 Ma monazite decreases with increasing Y content, which indicates that it likely formed under the retrograde stage during garnet breakdown. Based on the oldest metamorphic ages, the initial India-Asia collision occurred no later than 50−44 Ma in the eastern Himalayan syntaxis. The multimodal age patterns of the metamorphic zircon and monazite indicate that the Indian continent underwent multistage HP and retrograde metamorphism in the eastern Himalayan syntaxis. The nearly contemporaneous HP and retrograde metamorphism indicate that the Indian continent continued subducting while the earlier HP metamorphic slices detached and exhumed.

Multistage growth of garnet fingerprints the behavior and property of metamorphic fluids in a Paleotethyan oceanic subduction zone

Metamorphic fluids released from the subducting crust are of great importance to understand the recycling of volatile materials at convergent plate margins. Garnet in metamorphic rocks can retain chemical zonation and crystal inclusions produced during crustal subduction, providing the record of geochemical recycling in subduction zones. This paper presents a combined study of mineralogy and geochemistry for metamorphic garnets in oceanic-type eclogite from the Paleotethyan subduction zone in the Hong'an orogen, east-central China. The results show distinct zonation of major and trace elements, crystal inclusions, water contents, and oxygen fugacity in garnet. Five stages of garnet growth were recognized based on the garnet composition and phase equilibrium modelling. Growth of Stage I to IV garnets occurs during prograde metamorphism of the Paleotethyan oceanic crust from blueschist to eclogite facies along low geothermal gradients of 7.8–9.7 °C/km. Stage V garnet was formed through dissolution and reprecipitation during mineral-fluid reaction in the early exhumation stage. Garnet grains exhibit a decrease of water content from core to rim, indicating a gradual decrease of bulk water content in host eclogite during the garnet growth. Combined with the theoretical calculation based on the mineral modes and mineral water contents, it is suggested that the subducting oceanic crust would release reduced amounts of fluids during prograde metamorphism from greenschist to eclogite facies. The different garnet zones have f O 2 values varying from ΔFMQ+1.77 to ΔFMQ+3.26, suggesting that the fluids released from the subducting oceanic crust were oxidizing during subduction to peak eclogite facies and its early exhumation stage. These garnet f O2 values are correlated with the water contents of water-saturated garnet, implying that the water content of metamorphic garnet is a potential means to recover the redox state of its host eclogite. The increase of f O2 values during prograde metamorphism of the eclogite indicates the breakdown of chlorite and possible fluid influx from serpentinite, whereas the significant drop of f O2 values during the early exhumation stage indicates the breakdown of lawsonite to release the oxidized fluid. This study demonstrates that a combined study of water content, major and trace elements, and mineral inclusions in metamorphic garnet can potentially provide a new perspective into the behavior and property of fluids released from the subducting oceanic crust. • Garnet exhibits zoning in inclusions, major-trace elements, water content and oxygen fugacity. • Multiple stages of garnet growth were recognized along the P-T path of Hong'an eclogite. • Garnet water contents reflect decrease of fluid release from subducting oceanic crust. • Garnet water contents are correlated with redox conditions of its host eclogite. • Oxidized fluid is released during the dehydration of the subducting oceanic crust.

Integration of multi-sensor remote sensing, geological and geochemical data for delineation of Pb–Zn bearing carbonates of Middle Aravalli group in Zawar–Dungarpur Belt, NW India

The rocks of the Aravalli Protocontinent of NW India are enriched in lead–zinc bearing deposits amongst which the Zawar mineralized belt is one of the famous for base metal deposits and was mined since ancient times. In the present study, an attempt has been made to identify and map the extension of the mineralized belt and base metal prognostic zones using the integration of multi-sensor remote sensing, geological and geochemical data. Remote Sensing studies were carried out using ASTER, AVIRIS-NG, and ASAR datasets to understand the extension and associated structural features of host rocks (dolomite in the present case) of lead–zinc mineralization from the Middle Aravalli Group. Relative band depth (B6 + B9/B8) was used to delineate the dolomite of the region using the ASTER imagery. Mineral map was derived using the AVIRIS-NG dataset with the help of the MTMF algorithm. Multifrequency and multipolarization ASAR datasets demarcated the structural features in the complexly deformed rocks of the extended belt. The obtained results from remote sensing were validated with the help of geological and geochemical studies. Geological studies (field surveys and petrographic studies) confirmed the presence of dolomites and associative mafics. Mineralogical, major oxides and trace elements data further substantiated the presence of dolomite, associated sulfides such as galena, sphalerite, pyrite, and chalcopyrite, and lead, zinc and copper in the Zawar–Dungarpur Belt. Presence of chromium and nickel were observed through the trace element studies of dolomite belt. The trace elements interpolated maps were superimposed by traced structural maps using ASAR datasets. The densely populated E-W lineaments are considered the suitable zones for base metal accumulation. These lineaments carried the base metal bearing fluid along with a low concentration of Chromium and Nickel. Under the finding of this study, the northern head of Hati Magra and near Keekawat are the suitable zones for Pb–Zn sulfide mineralization.

The evolution of refertilized lithospheric mantle beneath the northeastern Siberian craton: Links between mantle metasomatism, thermal state and diamond potential

Although the diamond potential of cratons is linked mainly to thick and depleted Archean lithospheric keels, there are examples of craton-edge locations and circum-cratonic Proterozoic terranes underlain by diamondiferous mantle. Here, we use the results of comprehensive major and trace-element studies of detrital garnets from diamond-rich Late Triassic (Carnian) sedimentary rocks in the northeastern Siberia to constrain the thermal and chemical state of the pre-Triassic mantle and its ability to sustain the diamond storage. The studied detrital mantle-derived garnets are dominated by low- to medium-Cr lherzolitic (∼45%) and low-Cr megacrystic (∼39%) chemistries, with a significant proportion of eclogitic garnets (∼11%), and only subordinate contribution from harzburgitic garnets (∼5%) with variable Cr2O3 contents (1.2–8.4 wt.%). Low-Cr megacrysts display uniform, “normal” rare-earth element (REE) patterns with no Eu/Eu* anomalies, systematic Zr and Ti enrichment (mainly within 2.5–5), which are evidence of their crystallization from deep metasomatic melts. Lherzolitic (G9) garnets exhibit normal or humped to MREE-depleted sinusoidal REE patterns and elevated Nd/Y (up to 0.33–0.41) and Zr/Y ratios (up to 7.62). Rare low- to high-Cr harzburgitic (G10) garnets have primarily “depleted”, sinusoidal REE-patterns, low Ti, Y and HREE, but vary significantly in Zr-Hf, Ti and MREE-HREE contents, Nd/Y (within 0.1–2.4) and Zr/Y (1.53–19.9) ratios. The observed trends of chemical enrichment from the most depleted, harzburgitic garnets towards lherzolitic (including high-Ti high-Cr G11-type) garnets and megacrysts result from either voluminous high-temperature metasomatism by plume-derived silicate melts or recurrent mobilization of less voluminous kimberlitic or related carbonated mantle melts, rather than the initially primitive, fertile nature of the Proterozoic SCLM. Calculated Ni-in-garnet temperatures (primarily within ∼1150–1250 °C) indicate their derivation from at least ∼220 km thick Cr-undersaturated lithosphere at the relevant Devonian to Triassic thermal flow of ∼45 mW/m2 or cooler. We suggest the existence of rare harzburgitic domains in the primarily lherzolitic diamond-facies SCLM beneath the northeastern Siberian craton at least by Triassic, whereas the abundance of eclogitic garnets, predominance of E-type inclusions in placer diamonds and specific morphologies argue for diamondiferous eclogites occurring within a ∼50–65 kbar diamond window of the Olenek province by the same time.

Response of trace elements to partial melting of felsic crust at high to ultrahigh temperatures: Implications for granite geochemistry

It is known that partial melting and melt extraction of crustal rocks result in chemical differentiation of the continental crust. But it is unknown how these two processes have affected the composition of granites due to a limited knowledge of trace element behaviors during crustal anatexis. In order to quantify this issue, a combined study of whole-rock and mineral trace elements and mineral modal proportions was conducted for high-temperature (HT) to ultrahigh-temperature (UHT) felsic granulites from the Tongbai orogen in central China. Reconstruction of LREE budgets suggests that LREE mainly reside in monazite in both HT and UHT granulites. As monazite is predicted to be not stable at UHT conditions in the modelling of previous studies, the presence of monazite in the Tongbai UHT granulites suggest that it was not sufficiently dissolved into anatectic melts. Considering monazite mainly occurs as interstitial grains, fast melt-residue separation may be the dominant factor for impeding its dissolution. Calculation of mineral/mineral trace element ratios indicates that K-feldspar has a higher capacity to accommodate Ba and Sr than biotite and plagioclase, with DBaK-feldspar/biotite of 2.5–3.0 and DSrK-feldspar/plagioclase values of 1.4–1.9, and ilmenite can preserve more Nb and Ta than biotite with DNbbiotite/ilmenite values of 0.07–0.1 and DTabiotite/ilmenite values of 0.04–0.05. In addition, partitioning of first row transition elements (FRTE) was constrained in the felsic granulites, with preference of Sc into garnet, and Co, V, Ni, and Cr into biotite. Modelling based on the presently constrained partition coefficients indicates that trace elements show consistent differentiation trends during anatexis of various felsic rocks, with enrichment of Sr, Ba, Nb, Ta and FRTE but depletion of Rb in anatectic restites. The high DNb/Ta values of biotite and ilmenite cause the residues produced by biotite dehydration melting to be commonly of higher Nb/Ta ratios than protoliths, indicating that the residues are potentially high Nb/Ta reservoirs. In contrast, the change of peritectic minerals due to various protolith compositions and melting conditions results in differential responses of Sr, Ba, and FRTE to partial melting, suggesting that these elements may be useful indicators to trace the petrogenetic process of granites. The correlation between Ba and Sc contents or between Sr/Ba and Sc/Co ratios is demonstrated to be a valid index in discriminating melts from metagreywackes and metapelites due to different modes of garnet, orthopyroxene, and K-feldspar in their anatectic residues. Moreover, as the proportions of garnet and orthopyroxene in the residues are significantly influenced by melting pressures, the Sc/Co ratio and Sc content of granites can be used to trace their anatectic depth.

Non-hydrothermal saddle dolomite in Upper Cambrian dolostones of Tarim Basin: evidence from C–O–Sr isotopic and in-situ trace elemental studies

Non-hydrothermal saddle dolomite in Upper Cambrian dolostones of Tarim Basin: evidence from C–O–Sr isotopic and in-situ trace elemental studies

A unique stone skipping-like trajectory of asteroid Aletai.

Meteoroids/asteroids could deposit energy to Earth during their entries, which arouses great concerns. Strewn field, as a product of meteoroids/asteroids breakup, comprehensively reflects the trajectory, dynamics, and physical properties of meteoroids/asteroids. It typically has a length of several to a dozen kilometers. Nevertheless, the recently found massive Aletai irons in the northwest China comprise the longest known strewn field of ~430 kilometers. This implies that the dynamics of Aletai could be unique. Petrographic and trace elemental studies suggest that all the Aletai masses exhibit unique compositions (IIIE anomalous), indicating that they were from the same fall event. Numerical modeling suggests that the stone skipping–like trajectory associated with a shallow entry angle (e.g., ~6.5° to 7.3°) is responsible for Aletai’s exceptionally long strewn field if a single-body entry scenario is considered. The stone skipping–like trajectory would not result in the deposition of large impact energy on the ground but may lead to the dissipation of energy during its extremely long-distance flight.

Trophic transfer, bioaccumulation, and potential health risk of trace elements in water and aquatic organisms of Yundang Lagoon at Xiamen in China

In this study, distribution and accumulation of trace elements (Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb) in water, tissues of aquatic organisms (e.g. fishes: Oreochromis niloticus, Platycephalus indicus, Clupanodon punctatus; crabs: Charybdis japonica, Portunus sanguinolentus, and Charybdis varuegata; prawns: Litopenaeus vannamei, Metapenaeus joyneri, Penaeus japonicas, Penaeus penicillatus; mollusks: Mytilus spp., Perna spp.), and trophic transfer in food web were investigated in Yundang Lagoon at Xiamen in China. Most of the studied metals such as Cr, Mn, Ni, Cu, Cd, and Pb were biodiluted in the food web except As which was biomagnified in the food web. Moreover, the target hazard quotient and total target hazard quotient risk values were higher than threshold limit values indicating that non-carcinogenic health risk to the inhabitants due to consumption of aquatic organisms.

Pilot Study of Trace Elements in the Infusion of Medicinal Plants Used for Diabetes Treatment.

The purpose of this study was to evaluate trace element contents in different medicinal plants used for diabetes treatments by residents in Asir region. Five medicinal plants—Tut leaves (Mulberry), olive leaves (Olea europaea), clove (Syzygium aromaticum), Luban Dhakar (Boswellia carterii), and Karela or bitter melon (Momordica charantia)—were collected from two cities, Khamis Mushait and Abha, in the Asir region, Saudi Arabia. Infusions (hot water extracts) were obtained from each plant, and elemental analysis was conducted using inductively coupled plasma mass spectrometry (ICP-MS). Fourteen elements (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Cd, Ba, and Pb) were measured in all plants. The results revealed that the fourteen elements were present at different levels (µg/g) in all plants. Momordica charantia exhibited high levels of essential (Mn (251.4), Co (1.18), Cu (54.64), and Se (2.18)) and toxic elements (Al (39.20), As (0.57), Cd (0.33), and Pb (4.48)), followed by Syzygium aromaticum (Mn (736.36)) and Boswellia carterii (Pb (0.93)), which exceeded the PMTDI in traditional doses used for diabetes treatments. However, Mulberry and Olea europaea did not exceed the daily guideline values for all elements. Based on our findings, we cautiously recommend the latter two plants for the traditional treatment of diabetes, because they are not considered as source of harm based on their levels of elements. Their use should be restricted by comprehensive compound analysis to guarantee their safe use.