High Li Content Research Articles

Possible accumulation of critical metals in plants that hyperaccumulate their chemical analogues?

Lithium (Li), gallium (Ga) and indium (In) are industry-critical metals, with no known plant species that (hyper)accumulate these metals to any substantial degree. We hypothesised that sodium (Na) hyperaccumulators (i.e., halophytes) may accumulate Li, whilst aluminium (Al) hyperaccumulators may accumulate Ga and In, based on the chemical similarities of these elements. Experiments were conducted in hydroponics at various molar ratios for six weeks to determine accumulation in roots and shoots of the target elements. For the Li experiment, the halophytes Atriplex amnicola, Salsola australis and Tecticornia pergranulata were subjected to Na and Li treatments, whilst for the Ga and In experiment, Camellia sinensis was exposed to Al, Ga, and In. The halophytes were able to accumulate high shoot Li and Na concentrations reaching up to ~10 g Li kg−1 and 80 g Na kg−1, respectively. The translocation factors for Li were higher than for Na (about two-fold) in A. amnicola and S. australis. The results from the Ga and In experiment show that C. sinensis is capable of accumulating high concentrations of Ga (mean 150 mg Ga kg−1), comparable with Al (mean 300 mg Al kg−1), but virtually no In (<20 mg In kg−1) in its leaves. Competition between Al and Ga suggests that Ga might be taken up via Al pathways in C. sinensis. The findings suggest that there are opportunities to explore Li and Ga phytomining on respective Li- and Ga-enriched mine water/soil/mine waste materials using halophytes and Al hyperaccumulators to complement the global supply of these critical metals.

One step hot-pressing method for hybrid Li metal anode of solid-state lithium metal batteries

Safety issues induced by infinite anode volume change and uncontrolled lithium (Li) dendrite growth have become the biggest obstacle to the practical application of Li metal batteries. In addition, the traditional rolling method makes it difficult to manufacture thin Li foil with high mechanical strength and low Li content. Herein, a three-dimensional (3D) lithophilic carbon paper/copper (Cu) current collector hybrid anode with ultra-low Li metal content is prepared by a hot-pressing method. The highly reversible and stable lithiophilic layer LiCx formed in situ by heating/pressing treatment provides abundant nucleation sites and reduces the Li nucleation overpotential, thereby effectively suppressing Li dendrite growth. Moreover, the volume change and pulverization problems of Li metal anode during deposition/stripping also can be accommodated by the 3D skeleton. The optimization effect has been directly confirmed by in-situ optical and ex-situ scanning electron microscope observation. Therefore, highly stable performance (158.4 mA h g−1 at 2 C after 200 cycles with a capacity retention of 95.24%) in Li@LCP-Cu||NCM811 coin cell can be achieved. Furthermore, the solid-state battery assembled with the hybrid anode, poly(vinylidene fluoride) (PVDF)-based polymer electrolyte and polyethylene oxide (PEO) interface functional layer also exhibits the best electrochemical and safety performance, which also proves that the Li@LCP-Cu anode has great potential for application in solid-state batteries.

Granite alteration as the origin of high lithium content of groundwater in southeast Hungary

The study aimed to find the origin of the high lithium content of groundwater in southeast Hungary. To be concerned with assessing the economic potential of lithium in these waters, it is necessary to investigate the lithium-releasing geochemical processes. For this purpose, granite and pegmatite samples were analysed for lithium content and alteration from various Battonya Complex locations. The key alteration processes are the chloritisation of biotite and the sericitisation of feldspar, which are hypothesised to mobilise Li from minerals into the geothermal waters. Whole-rock analyses show that the 36 ppm Li concentration in one sample (S1) exceeded the average crustal Li concentration (∼20 ppm), while three samples have near-average crustal concentrations. The Li content of rock samples decreases along with the increasing intensity of alteration. The Li concentration of biotite, muscovite, chlorite, feldspar and quartz from granites and pegmatite was measured using laser-induced-breakdown-spectrometry (LIBS). A total of 180 data points were analysed. Biotite and muscovite of the relatively fresh granites contain Li up to ∼3800 and ∼2500 ppm, respectively. Chloritisation is a hydrothermal alteration process in granites that can be described by the following reaction: biotite + plagioclase → chlorite + epidote + titanite + muscovite. As a function of chloritisation, Li concentration decreases two- and three orders of magnitude from biotite to chlorite in the more altered cases. A similar trend is observed for muscovite in parallel. Feldspars have Li of 17–141 ppm, while there is no correlation between the Li content of feldspars and the degree of alteration. Quartz contains constant low concentrations around the 1 ppm detection limit, with one outlier value of 48 ppm. Chloritisation of biotite is a possible explanation for the high Li content of the geothermal waters in the study area and possibly elsewhere. The main Li-bearing minerals of the Battonya Complex are biotite and muscovite. Chloritisation and subordinate sericitisation result in significant lithium loss. Chlorite can incorporate Li in its crystal lattice but to a lesser degree than the other sheet silicates, like biotite and muscovite.

Fabrication of CeCl3/LiCl/CaCl2 Ternary Eutectic Scintillator for Thermal Neutron Detection

To date, 3He gas has been commonly used to detect thermal neutrons because of their high chemical stability and low sensitivity to γ-rays, owing to their low density and large neutron capture cross-section. However, the depletion of 3He gas prompts the development of a new solid scintillator for thermal neutron detection to replace 3He gas detectors. Solid scintillators containing 6Li are commonly used to detect thermal neutrons. However, they are currently used in single crystals only, and their 6Li concentration is defined by their chemical composition. In this study, 6Li-containing eutectic scintillators were developed. CeCl3 was selected as the scintillator phase because of its low density (3.9 g/cm3); high light yield (30,000 photons/MeV); and fast decay time with four components of 4.4 ns (6.6%), 23.2 ns (69.6%), 70 ns (7.5%) and &gt;10 μs (16.3%), owing to the Ce3+ 5d-4f emission peak at approximately 360 nm. Crystals of the CeCl3, LiCl and CaCl2 ternary eutectic were fabricated by the vertical Bridgman technique. The grown eutectic crystals exhibited Ce3+ 5d-4f emission with a peak at 360 nm. The light yield was 18,000 photons/neutron, and the decay time was 10.5 ns (27.7%) and 40.1 ns (72.3%). Therefore, this work demonstrates optimization by combining a scintillator phase and Li-rich matrix phase for high Li content, fast timing, high light yield and low density.

Lithium in the Environment and its Effects on Higher Plants

Summary Lithium (Li) is present in low concentrations in all parts of the biosphere, including living organisms. It reaches the terrestrial environment primarily through natural processes to which parent substrate was subjected during pedogenesis, and due to anthropogenic activities. Individual soil types differ regarding Li content; for example saline and loamy soils have higher Li content. It is found in low concentrations primarily in ionic form in aquatic environments in surface and groundwater. It is mobile in the soil and thus soil contamination with Li can lead to its higher concentration in groundwater. In the environment, Li reaches the atmosphere from Li-emitting sources. It is widely used in many industries, lately in the Li-ion batteries in electronic goods, due to which it may be a potential risk for the environment. Terrestrial plants take up Li largely via roots from the soil, but also via shoots from the atmosphere. In the soil, Li is mostly bound by clay fraction and organic matter. During the uptake, transport and distribution in plants it behaves like an alkaline earth ion, not like an alkali ion. The fact that Li is immobile in the phloem supports this claim. Its ascendent transport mainly depends upon the transpiration intensity. More Li is taken up by plants from acid soils than from alkaline soils. Li is non-essential for plant growth and development. In low concentrations it can be stimulative and affect chemical composition and organic production of plants. Li plays an important role in the metabolism of halophyte species. It is increasingly regarded as an essential trace element for animals and humans, and used in human medication to treat dementia, suicidal ideation, aggression and violence. High levels of Li are toxic to all plants, but uptake and sensitivity to Li are species-dependent. Some representatives of the Ranunculaceae, Solanaceae and Asteraceae families are characterized by increased Li accumulation, while Poaceae, Liliaceae, Brassicaceae, Caprifoliaceae show low accumulation. High concentrations of Li have adverse effects on many physiological and biochemical processes in plants (DNA, RNA and protein pathways, water relations, content of photosynthetic pigments, photosynthesis, production of reactive oxygen species, lipid peroxidation of the cell membranes etc.), which is further manifested as stunted growth, developmental disorder, visual symptoms, interveinal necrosis and necrosis along the leaf margins. Hyperaccumulator plants extract significant amounts of Li and are therefore used in phytoremediation. Better understanding of the effects of beneficial and phytotoxic concentrations of Li on metabolism and plant growth and development remains vital for the improvement of the knowledge about biological activity of Li in higher plants.

Lithium Accumulation in Salvinia natans Free-Floating Aquatic Plant.

The new context of the intensive use of lithium-based batteries led to increased production of Li and Li-containing wastes. All these activities are potential sources of environmental pollution with Li. However, the negative impact of Li on ecosystems, its specific role in the plants’ development, uptake mechanism, and response to the induced stress are not fully understood. In this sense, the Li uptake and changes induced by Li exposure in the major and trace element contents, photosynthetic pigments, antioxidant activity, and elemental composition of Salvinia natans were also investigated. The results showed that Salvinia natans grown in Li-enriched nutrient solutions accumulated much higher Li contents than those grown in spring waters with a low Li content. However, the Li bioaccumulation factor in Salvinia natans grown in Li-enriched nutrient solutions was lower (13.3–29.5) than in spring waters (13.0–42.2). The plants exposed to high Li contents showed a decrease in their K and photosynthetic pigments content, while their total antioxidant activity did not change substantially.

Olivines and Their Melt Inclusions in Potassic Volcanic Rocks Record Mantle Heterogeneity beneath the Southern Tibet

Abstract Constraints on mantle heterogeneity are important for understanding geochemical differentiation and recycling in Earth’s interior. Alkali basalts are of particular interest in this context due to the clear signatures of recycled components that they yield. Previous studies have focused more on oceanic basalts than on continental mafic rocks because the chemical and isotopic characteristics of the latter are often modified by crustal contamination; however, high-forsterite olivine crystals and olivine-hosted melt inclusions may record the compositions of primitive melts before extensive crustal contamination, providing valuable insights into mantle heterogeneity. Here we report the results of high-precision major-, minor-, and trace-element and Pb isotope analyses of olivine phenocrysts and melt inclusions from the Sailipu potassic alkali basalts from southern Tibet, which constrain the mantle source of continental potassic alkali basalts. The minor- and trace-element compositions of the olivine phenocrysts (e.g. Ni and Ca contents and 100 × Mn/Fe, 10 000 × Zn/Fe, and Ni/Co ratios) suggest that the primary magmas were derived from a phlogopite-bearing pyroxenite source in which peridotite residues were also present. The low- and high-Li contents of the olivine phenocrysts suggest the recycling of continental crustal material in their mantle source. Comparing the major-element compositions (e.g. SiO2, TiO2, Al2O3, MnO, CaO, and Na2O contents), FCMS and FCKANTMS parameters, and pseudo-ternary projections of the primary Sailipu magmas with experimental data suggests that the primary magmas were partial melts of olivine-poor or carbonated olivine-poor lithologies with a small amount of peridotite residue. The negative Nb and Ta and positive Pb anomalies seen in primitive mantle-normalized trace-element patterns and the extremely low Nb/U ratios of the melt inclusions suggest that recycling of continental crust was the main process involved in enriching the mantle source of the Sailipu magmas. The heterogeneous Pb isotopic compositions of the melt inclusions (208Pb/206Pb = 2.089 – 2.158; 207Pb/206Pb = 0.851 – 0.858) are consistent with the presence of peridotite residue in this source. The subduction of Indian continental crust introduced enriched material (including carbonatites) into the mantle.

Asthenospheric mantle metasomatized by subducted marine sediments: Li isotopic evidence from Dagze mafic rocks, southern Tibet

Lithium (Li) isotopes show large isotopic fractionation during low temperature processes and have been widely used to trace subduction components at convergent margins. To identify recycled subducting components in the asthenospheric mantle, we report the lithium concentrations and isotopic compositions of the ca. 90 Ma Dagze mafic rocks from the eastern Gangdese Arc, southern Tibet, along with their corresponding whole-rock analyses and Sr-Nd-Pb isotope data. They mainly comprise basalts and diabases with high MgO (7.2–8.3 wt%) and low K 2 O (0.02–0.68 wt%) contents. These rocks show slightly variable initial 87 Sr/ 86 Sr ratios (0.7048 to 0.7057), relatively low and homogeneous Pb isotope ratios ( 206 Pb/ 204 Pb = 18.2948–18.6462, 207 Pb/ 204 Pb = 15.5587–15.6132, 208 Pb/ 204 Pb = 38.3843–38.8352) and positive ε Nd (t) values (3.0–4.9), similar to ophiolites from the Indus-Yarlung Tsangpo suture (IYTS). However, they are remarkably depleted in high field strength elements (HFSE; such as Nb and Ta) and slightly enriched in light rare earth elements (LREE) [(La/Yb) N = 2.8–4.4], both of which imply their mantle affinities with distinctive arc signatures. The δ 7 Li values of these rocks range from −2.0 to +2.0‰ (average = −0.7‰), with the majority of samples falling outside the depleted mantle range (+3.4 ± 1.4‰). They exhibit high Li contents (13.2 to 34.1 ppm) and Li/Y ratios (0.8 to 2.2), which are comparable with marine sediments. The negative correlation between Li/Y ratios and δ 7 Li values also suggests the addition of subducted marine sediments. The modeling of δ 7 Li values in combination with Pb-Sr-Nd isotopic ratios suggests that ~1 to 5% of marine sediments have been added into the mantle source of the Dagze mafic rocks. Combined with a previous study, we suggest that the Dagze mafic rocks were derived from the upwelling asthenospheric mantle metasomatized by subducted marine sediments. • Reporting the negative δ 7 Li values of the Dagze mafic rocks. • Demonstrating the lithium isotopic heterogeneities in the asthenospheric mantle. • Modeling ~1 to 5% of marine sediments to the mantle source of the Dagze mafic rocks.

Effects of High Li Content on the Crystal Structure and Properties of Li2+xTiO3 Ceramic Pebbles by Sol-Gel Method

Effects of High Li Content on the Crystal Structure and Properties of Li2+xTiO3 Ceramic Pebbles by Sol-Gel Method

Enrichment mechanisms of lithium for the geothermal springs in the southern Tibet, China

• The deeper fluids have relatively high magmatic Li contents from the degassing of the semi-molten state magma. • Evaporation further concentrated the Li in the geothermal springs in Tibet. • Subsequent mixing resulted in the observed differences in Li concentrations of the thermal springs. • The Li-rich saline lakes may originate from the concentration of geothermal springs. As low-grade lithium (Li) extraction technology improves, Li-rich geothermal fluids may become an alternative Li source in the future. Most geothermal springs in southern Tibet, China, have notably high Li contents, but the fluids’ Li origins and enrichment processes remain unclear. Therefore, this study investigated the Li enrichment mechanisms in the study area based on 307 hydrogeochemical data of thermal spring waters selected from the literature. Our findings confirm that most Li-enriched geothermal springs in southern Tibet are chemically influenced by magma. Also, K-Mg and chalcedony geothermometers’ estimates indicated that most of the springs originate from shallow reservoirs with temperatures below 200 °C, although some higher temperature deep reservoirs may exist beneath Tibet. Moreover, we found that two hydrochemical processes mainly resulted in the relatively high Li concentrations in southern Tibet’s thermal fluids. First, magmatic Li enrichment resulted from the semi-molten state magma degassing rather than leaching from the surrounding rocks in the deeper reservoirs. Subsequent mixing of the Li-rich deep fluids with varying amounts of infiltrating groundwater formed the shallow reservoirs during ascent to the earth’s surface resulting in the observed differences in Li concentrations of the thermal springs from these reservoirs. Secondly, evaporation further concentrated the Li in the Li-rich geothermal springs in southern Tibet, resulting in higher Li levels than in other magmatic thermal springs. The present study could not establish the Li source for the Tibet thermal springs with low Cl concentrations because they may mix with large amounts of infiltrating groundwater; however, it is more likely that magmatic Li still accounts for a large portion of the total Li.

Stagnated eclogitic slab-related shoshonitic series volcanic rocks in West Tianshan, Xinjiang, China: Insights from Li-B-Sr-Nd-Hf-Pb isotope and trace element compositions

This study presents major, trace element and Li-B-Sr–Nd–Pb-Hf isotope compositions of post-collisional (Permian) shoshonitic volcanic rocks (SVRs) from West Tianshan, NW China. Zircon U Pb dating indicates that the West Tianshan SVRs were mainly formed in the late Early Permian (272–279 Ma). They include absarokites, shoshonites and banakites, which have variable SiO 2 (46–63 wt%) and K 2 O (2.12–8.12 wt%) contents. They display enrichment in light rare earth elements (LREE) and depletion in heavy rare earth elements. They are enriched in large ion lithophile elements (e.g., La, Rb and Ba) and depleted in high field strength elements (e.g., Nb, Ta and Ti) with slightly negative to negligible Eu anomalies, pronounced positive Pb anomalies and low Nb/U (9.32 ± 6.54), Ce/Pb (0.14–10.0, average 5.03 ± 3.02), relatively high Nb/Ta (16.74 ± 2.72) and Zr/Hf (39.56 ± 6.06) ratios. They have relatively high Li contents (26.0–93.0 ppm) and B contents (6.19–84.7 ppm), and low but variable δ 7 Li (−4.0‰ to +2.4‰). They are characterized by low ( 87 Sr/ 86 Sr) i (0.7045–0.7068), positive ε Nd (t) values (+0.31 − +5.53), relatively low 206 Pb/ 204 Pb (18.16–18.65), 207 Pb/ 204 Pb (15.51–15.63) and 208 Pb/ 204 Pb (37.97–39.22) and positive ε Hf (t) (+5.4 − +12.5). These features consistently suggest a metasomatized enriched mantle source having affinities with an EM I-like reservoir for the SVRs. Source enrichment was generated dominantly by subducted slab related aqueous fluid and altered oceanic crust (AOC) melts. Dehydration modeling of Li and B isotopes and Li, Y, B, Nb trace element fractionation collectively show that the flat, deeply subducted and stagnated, eclogitic slab suffered progressive dehydration(~5–12%)and was distinctly 7 Li-depleted. Based on these compositional features and model calculations, we suggest that West Tianshan SVRs had an enriched mantle source metasomatised by aqueous fluid and hydrous slab melt, and their parental magmas were derived from variable mixing of spinel and garnet peridotite (60Gt:40Sp − 80Gt:20Sp). Taking into account petrogenetic and regional tectonic data, we suggest that the West Tianshan SVRs developed in an intraplate setting during the late Early Permian. It is most probable that the Early Permian Tarim mantle plume, located in the south side of the study area, promoted Early Permian asthenospheric upwelling that resulted in melting of a fossil subduction-enriched source to produce shoshonitic volcanic rocks in the West Tianshan. • Lower δ7Li and wider range are evidently lighter than most volcanic suites world-wide. • A deeply subducted and stagnated eclogitic slab is one end-member of enriched source. • Parental magmas were from mixing of garnet and spinel peridotite (60/40–80/20). • SVRs formed in post-collision transition from subduction-related to intraplate setting.

Corrosion behaviour induced by crystal structure transformation of Mg alloy with AlTiB

The microstructural evolution and corrosion behaviour of three kinds of Mg alloy containing AlTiB (α, α + , ) were investigated. The result showed that changing Li content can transform the matrix of Mg alloy from α-Mg to -Li. Except for -Li, the microstructural morphology of α-Mg is refined by TiB2, In the study of corrosion behaviour, a structure of multiple layers is formed on corrosion surfaces, and the α + alloy has a poor corrosion resistance which results from a mechanism of the dynamic galvanic couple between α-Mg and -Li. However, the -Li alloy with high Li content has relatively good corrosion resistance.

Prediction of stable Li-Sn compounds: boosting ab initio searches with neural network potentials

The Li-Sn binary system has been the focus of extensive research because it features Li-rich alloys with potential applications as battery anodes. Our present re-examination of the binary system with a combination of machine learning and ab initio methods has allowed us to screen a vast configuration space and uncover a number of overlooked thermodynamically stable alloys. At ambient pressure, our evolutionary searches identified an additional stable Li3Sn phase with a large BCC-based hR48 structure and a possible high-T LiSn4 ground state. By building a simple model for the observed and predicted Li-Sn BCC alloys we constructed an even larger viable hR75 structure at an exotic 19:6 stoichiometry. At 20 GPa, low-symmetry 11:2, 5:1, and 9:2 phases found with our global searches destabilize previously proposed phases with high Li content. The findings showcase the appreciable promise machine-learning interatomic potentials hold for accelerating ab initio prediction of complex materials.

Characterization of Pennsylvanian Paleosols in Indiana with a Special Reference to Rare Earths (REE) and Lithium

This study characterizes Pennsylvanian paleosols from coal-bearing strata in Indiana, with the main emphasis on the abundance and distribution on rare earths (REE) and lithium (Li). Eleven locations in southwest Indiana were selected for this study, targeting paleosols of both the Carbondale Group and the Raccoon Creek Group. Most paleosols were directly underlying coal beds. Lithologically, paleosols range from grey mudstones to greenish-gray claystones and occasional siltstones. In the Carbondale Group, the thickest paleosol horizons occur under the Danville and the Houchin Creek Coal Members, with their thickness reaching close to 10 feet. In the Raccoon Creek Group, the paleosol under the Wise Ridge Coal appears to be thickest (4.6 to 11.4 feet) and best developed. Total REE content in paleosol samples ranges from 138.8 ppm to 728.55 ppm, with an average range of 208.3 ppm (Colchester paleosol) to 342.9 ppm in the paleosol under the Upper Block Coal. Light REE dominate over heavy REE, and the variation in the light REE is responsible for the largest variations of the total REE. The largest amount of the heavy REE (61 ppm) occurs in the paleosol under the Lower Block Coal, whereas the paleosol under the Upper Block Coal has the largest variation in the heavy REE content (49 to 148 ppm). REE patterns for paleosol samples show very weak to no fractionation among light, medium, and heavy REE, with no major anomalies present. The majority of paleosols have REE values that are roughly representative of the upper continental crust. Only some paleosols are slightly enriched and these are paleosol samples under the Danville Coal and the Upper Block Coal. Lithium content in the paleosol samples shows a variation from 21 ppm to 530 ppm. On average, the Wise Ridge Coal is richest in Li (249.3 ppm), followed by Viking B Coal (190.8 ppm). The coals of the Brazil and Staunton Formations have higher Li content than the younger coals. Although this study has not uncovered large concentrations of REE or lithium, the wide range of concentrations and potential ease of their extraction from these clay-rich rocks imply that the paleosols deserve further examination, and the current study can be used as a screening guide for more focused investigation.

Study on the microstructure and age hardening capability in Al–Cu–Li alloys with different Cu/Li ratio

Abstract The microstructural evolution during natural ageing and artificial ageing treatment has been quantified in Al–Cu–Li alloys with Cu/Li ratios of 2.3 and 3.9. Methods including various ageing, hardness testing, transmission electron microscopy and differential scanning calorimetry were employed. The precipitation of T1 (Al2CuLi) phase was confirmed for the first time in the high Li content alloy under natural ageing treatment for 5 months, while the Li-lean alloy exhibits barely any precipitation at room temperature. Under artificial ageing, the Li-rich alloy exhibits a significant increase in hardness due to the formation of high density spherical δ′ phase. On the other hand, the increasing Cu/Li ratio promotes the precipitation of the Cu containing precipitates T1 and θ (Al2Cu), the high Cu/Li ratio (3.9) alloy shows a recovery of ductility, with a uniform elongation of ∼20 %, which is caused by the strong interactions between the dislocations and the nano-scale T1 and θ precipitates. Meanwhile, as the main strengthening precipitate changes from θ and T1 to T1 alone with prolonged ageing time, the alloy displays a double-peak age hardening behavior. This work sheds light on the design of high strength and ductile Al–Li alloys through the well-controlled T1 phase precipitation.

Formation of the Lened W-(Be) Skarn Deposit by Neutralization of a Magmatic Fluid—Evidence from H3BO3-Rich Fluids

Magmatic-hydrothermal systems, especially those causing the formation of tungsten deposits, may be enriched in boron, as is suggested by the presence of hydrothermal tourmaline. This study examines the boron and metal (including tungsten) concentrations of quartz-hosted fluid inclusions in the Lened W-(Be) deposit of the Canadian Cordillera and resolves (i) the analytical challenges involved during fluid salinity calculations of B-rich fluids and (ii) the relationship between fluid chemical composition and ore-forming processes involved at Lened. The aqueous fluid inclusions from this study have high CO2 and boron contents, indicated by the presence of a carbonic phase and sassolite crystals (H3BO3) in fluid inclusions. The boron content of the aqueous liquid phase (0.5 wt. %) was determined using microthermometric and Raman spectroscopic analyses. Boron was judged the most appropriate internal standard for quantifying the LA-ICP-MS data from these inclusions after calculation of salinity in the H2O-NaCl-H3BO3 system (3.5 to 5 wt. % NaCleq). Trace element data of the fluids show relatively high concentrations of Li (40 to 474 ppm), Al (56 to 1003 ppm), As (36 to 490 ppm) and Cs (68 to 296 ppm); and lower concentrations of Rb (3.6 to 77 ppm), Sr (0.4 to 23 ppm), Sb (1 to 32 ppm), Ba (0.6 to 163 ppm), Mg (6.9 to 7.6 ppm) and other metals, such as Be (2.4 to 10.2 ppm), W (2.4 to 27 ppm) and Cu (5.1 to 73 ppm). The high Cs and Li concentrations suggest a magmatic origin of the metals, while the moderate concentrations in Sr and Ba are indicative of fluid–rock interaction with the surrounding limestone. The presence of sassolite suggests that these fluids were highly acidic. The neutralization of this fluid through interaction with the surrounding limestone is the most probable trigger for scheelite precipitation. The presence of such high boron content in the magmatic fluid at Lened indicates the potential role in the enrichment of the source melt before fluid exsolution.

High strength BCC magnesium-Lithium alloy processed by cryogenic rolling and room temperature rolling and its strengthening mechanisms

Based on high Li content, optimizing the mechanical properties of Mg-Li alloy can bring about the good combination of ultra-low density and high strength, causing high specific strength. Reducing the deformation temperature can effectively maintain the strength improvement of deformed β-based Mg-Li alloy. In this work, the microstructures and mechanical properties of room-rolled (RR) and cryogenic-rolled (CR) Mg-16Li-4Zn-1Er (LZE1641) alloy were investigated. Results show that cryogenic temperature delays the dynamic recovery(DRV) and dynamic recrystallization(DRX). A tensile strength of 267 MPa can be obtained at CR60%, which is attributed to the nanocrystalline grains and the significantly higher dislocation density than that of the RR alloy. Further CR with 80% reduction makes the form of some alloying elements transform from solid state to precipitation phases, causing relatively decreased strength

Weathering intensity and lithium isotopes: A reactive transport perspective

Lithium isotopes have emerged as a powerful tool to probe the response of global weathering to changes in climate. Due to the preferential incorporation of ^6^Li into clay minerals during chemical weathering, the isotope ratio δ^7^Li may be used to interrogate the balance of primary mineral dissolution and clay precipitation. This balance has been linked to relative rates of chemical and physical denudation, such that dissolved δ^7^Li (δ^7^Li~diss~) is highest at moderate weathering intensities when chemical and physical denudation are comparable. However, we argue that current theory linking δ^7^Li to weathering regimes through fluid travel times are unable to explain observations of low δ^7^Li and high Li concentrations in rapidly eroding settings. In this study, we re-examine the relationships between δ^7^Li, Li concentration, and weathering regime by incorporating Li isotopes into simulations of weathering profiles using a reactive transport model (CrunchFlow) that includes advective fluxes of regolith to simulate variable erosion rates in response to uplift. In these simulations, fractionation is implemented through a kinetic fractionation factor during clay precipitation, which allows the δ^7^Li of dissolved and suspended loads in the model to vary as a function of Li/Al ratios in primary and secondary minerals. When the model is run over a range of infiltration and erosion rates, simulations reproduce observed global patterns of δ^7^Li~diss~ and suspended load δ^7^Li as a function of weathering intensity, controlled primarily by water travel times and mineral residence times in weathered bedrock. We find that reduced water travel times at low weathering intensity, however, are inconsistent with observations of high Li concentrations. As an alternative, we demonstrate how the rapid weathering of soluble, Li-rich minerals such as chlorite under low weathering intensities may resolve this apparent discrepancy between data and theory. We also suggest that observed patterns are consistent with geothermal Li sources under low weathering intensities. This work offers a foundation guiding future studies in testing potential mechanisms underlying global riverine δ*^7^*Li~diss~.

Tourmaline and zircon trace the nature and timing of magmatic-hydrothermal episodes in granite-related Sn mineralization: Insights from the Libata Sn ore field

AbstractThe Bin Yauri-Libata polymetallic ore district is a Sn and Au ore-bearing district in the Zuru schist belt, Northwestern Nigeria. The Libata Sn ore field is characterized by a set of cassiterite-bearing hydrothermal veins associated with Neoproterozoic Pan-African granites affected by deformation and low-grade metamorphism. The hydrothermal alteration associated with cassiterite-bearing quartz veins in the Libata deposit includes silicification, albitization, chloritization, and potassic alteration. In this study, geochemical and geochronological data from tourmalines and zircons from Sn-bearing lodes, unmineralized and altered granites is applied to reveal the timing, fluid composition, and source of ore-forming materials for tin mineralization in the Libata ore field. Zircon trace element and Hf isotopes [εHf(t) = +4.37 to +10.85] reveal a mantle-derived source with some crustal contribution for the melts forming the Libata Sn-bearing granites. LA-ICP-MS zircon U-Pb dating constrains the magmatic and hydrothermal ages to 650–646 and 649–646 Ma for the Libata granites. Overlapping zircon εHf(t) and 176Hf/177Hf but distinct 176Lu/177Hf and 176Yb/177Hf ratios from magmatic and hydrothermally altered zircons reveal a magmatic source for the hydrothermal fluids which triggered cassiterite deposition in the Libata ore field. Major element chemistry constrain tourmalines from the Libata ore field as schorls that show high alkalis, low-Ca contents, and moderate ☐ values (where ☐ is x-site vacancy). High Li, Zn, and Sn concentrations in tourmaline as well as Li/Sr and Ca-Fe-Mg ratios demonstrate that the tourmaline formed from granite-sourced fluid likely derived from the host Libata granites. Measured δ11B values from the Libata tourmaline range from –15.7‰ to –14.1‰. The δ11B of the mineralizing fluid is estimated to be –13.1 to –11.9‰ for the Libata tourmalines at 400–500 °C and overlaps with averages from fractionated granites worldwide. Therefore, our data show that tourmaline and zircon are useful tracers of magmatic-hydrothermal evolution in rare-metal-bearing granite systems.

Lithium isotope behavior under extreme tropical weathering: A case study of basalts from the Hainan Island, South China

Chemical weathering of silicate rocks (especially basalt) is an important sink of atmospheric carbon dioxide, and has an important impact on long-term carbon cycle and storage. Lithium (Li) isotopes have been regarded as a good tracer of chemical weathering, however, the behavior of Li isotopes in tropical settings is poorly understood. In this study, we studied the Li elemental and isotopic variation in the solid weathering products (soil and saprolite) from a highly-weathered (CIA ∼100%) basalt weathering profile (>15 m thick, including soil, saprolite, semi-weathered rock and fresh basalt) on the tropical Hainan Island in South China. The weathering products have 1.99–58.1 ppm Li, mostly below the average fresh basalt value (4.6 ppm, n = 5). The δ7Li values (−14.3 to 8.9‰) of the solid weathering products exhibit complex stratigraphic variation across the weathering profile. The Li and Mn enrichments coincide spatially, with the Mn-rich samples having the highest Li content and lowest δ7Li value. Lithium is enriched in the semi-weathered basalt sample, but its δ7Li value (−2.7‰) is close to that of fresh basalts (0.7–5.3‰, avg. 3.0‰, n = 5). Strontium isotope data show that the weathering profile is affected by marine aerosol input, and the marine strontium may have been leached to the profile bottom or out of it under extreme weathering. Sequential extraction results indicate that Li in the soil, saprolites (lower part), and semi-weathered basalt occurs mainly in the residual phase, while Li in the saprolites (middle part) occurs largely in Fe–Mn oxides. We suggest that Li isotope fractionation in the upper, middle and lower parts of the profile was controlled by, respectively, marine aerosol input and secondary mineral leaching, dissolution/re-precipitation of Fe–Mn oxides, and neoformation of secondary minerals from heavy pore water. Our results show that the preferential light Li isotope uptake by Fe–Mn oxides may have been the main cause for the major Li isotope fractionation in the Wenchang weathering profile.