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Diffusional isotope fractionation has been widely used to explain lithium (Li) isotope variations in minerals and rocks. Isotopic mass dependence of Li diffusion can be empirically expressed as D 7 Li D 6 Li = 6 7 β , where D is the diffusivity of a Li isotope. The knowledge about temperature and compositional dependence of the β factor which is essential for understanding diffusion profiles and mechanisms remains unclear. Based on the potential energy and interatomic forces generated by deep neural networks trained with ab initio data, we performed deep potential molecular dynamics (DPMD) simulations of several Li pseudo-isotopes (with mass = 2, 7, 21, 42 g/mol) in albite, hydrous albite, and model basalt melts to evaluate the β factor. Our calculated diffusivities for 7Li in albite and model basalt melts at 1800 K compare well with experimental results. We found that β in albite melt decreases from 0.267 ± 0.006 at 4000 K to 0.225 ± 0.004 at 1800 K. The presence of water appears to slightly weaken the temperature dependence of β , with β decreasing from 0.250 ± 0.012 to 0.228 ± 0.031 in hydrous albite melt. The calculated β in model basalt melt takes much smaller values, decreasing from 0.215 ± 0.006 at 4000 K to 0.132 ± 0.015 at 1800 K. Our prediction of β in albite and hydrous albite melts is in good agreement with experimental data. More importantly, our results suggest that Li isotope diffusion in silicate melts is strongly dependent on melt composition. The temperature and compositional effects on β can be qualitatively explained in terms of ionic porosity and the coupled relationship between Li diffusion and the mobility of the silicate melt network. Two types of diffusion experiments are suggested to test our predicted temperature and compositional dependence of β . This study shows that DPMD is a promising tool to simulate the diffusion of elements and isotopes in silicate melts.

A novel 7Li quantitative NMR (qNMR) method to analyze lithium was developed to determine the lithium content in real brine samples using benchtop NMR instruments. The method was validated, and limits of detection and quantification of 40 and 100 ppm, respectively, were determined. Linearity, precision, and bias were also experimentally determined, and the results are presented herein. The results were compared to those obtained using atomic absorption (AA) spectroscopy, currently one of the few validated methods for the quantification of lithium. The method provides both accurate and precise results, as well as excellent correlation with AA. The absence of matrix effects, combined with no need for sample preparation or deuterated solvents, shows potential applicability in the mining industry.

The ratio of NMR frequencies of lithium isotopes f(7Li)/f(6Li) = 2.6409061846(13) was determined with an error of 4.9·10–10. The use of a nuclear magnetic resonance spectrometer operating in the mode of simultaneous registration of signals from two nuclei to obtain data allowed the random and systematic errors in the measurement results to be reduced by an order of magnitude. The ratio of the resonant frequencies of water protons and 7Li ions was determined: f(H2O)/f(7Li) = 2.557100473(9) with an error of 3.5·10–9 for solutions with an extremely low concentration of LiOH*H2O salt in water and at a temperature of 25°C. Based on the obtained data, the magnetic moments of lithium nuclei were calculated: μ(6Li) = 0.8220454(25)μN, μ(7Li) = 3.2564171(98)μN. The known data on the magnetic moment of the proton and data on the electronic shielding of these nuclei were used. A comparison of the experimental data for μ(6Li) and μ(7Li) and the corresponding theoretical calculation data was performed.

Laser-induced breakdown spectroscopy (LIBS) is a technique capable of portable, quantitative elemental analysis; however, quantitative isotopic determination of samples in situ has not yet been demonstrated. This research demonstrates the ability of LIBS to quantitatively determine concentrations of 6Li in solid samples of lithium hydroxide monohydrate in a nominally 40 mTorr argon environment using chemometrics. Three chemometric analysis techniques (principal component regression, partial least squares regression, and neural networks analysis) are applied to spectra collected using a spectrometer with modest resolving power (λ/Δλ ≈ 27 000). This analysis suggests that bulk lithium isotopic assay can be determined using LIBS to within a 95% confidence interval in minutes to an hour for enrichment levels ranging from 3% to 85%. This has direct applications for the nuclear safeguards and geological exploration communities and others that desire a portable, stable isotope analytical technique. Additionally, isotope-specific self-absorption of atomic emission in a laser-produced plasma is observed for the first time.

The field of high-temperature Li isotope geochemistry has been rattled by major paradigm changes. The idea that Li isotopes could be used to trace the sources of fluids, rocks, and magmas had to be largely abandoned, because Li diffusion causes its isotopes to fractionate at metamorphic and magmatic temperatures. However, diffusive fractionation of Li isotopes can be used to determine timescales of geologic processes using arrested diffusion profiles. High diffusivity and strong kinetic isotope fractionation favors Li isotopes as a tool to constrain the durations of fast processes in the crust and mantle, where other geochronometers fall short. Time may be the parameter that high-temperature Li isotope studies will be able to shed much light on.

The significance of the problem of determining the concentration of beryllium in solutions is substantiated. A method of APESI mass-spectrometry (atmospheric pressure electrospray ionization with in-source atomization) is compared with a number of other common procedures used for solving the aforementioned problem and a number of advantages of APESI mass spectrometry are highlighted. The possibility of measuring the beryllium concentration in various chemical forms using APESI mass-spectrometry is studied. We used sulfate, nitric acid and chloride salts of beryllium. The measurements were carried out on a specialized small-sized mass spectrometer MI-20 «LowMass» developed at MS-Bio Company, Russia. A schematic diagram of the device designed to determine the concentration of beryllium in solutions is presented and described. A technique of solution preparation and measurement procedure are proposed. Presented ass spectra obtained on the samples containing beryllium and lithium isotopes were used as an internal standard. It is shown that beryllium can be detected from the salts of chloride and nitric acids with close relative sensitivity coefficients. The obtained detection limit for beryllium chloride in those measurements was ~1 – 2 × 10–8 M. At the same time, the analytical signal of beryllium cannot be detected during electrospray of the solution of beryllium sulfate under any experimental conditions. It has been suggested that this effect may be attributed to the features of dissolution of beryllium sulfate, in particular, to hydrolysis and formation of complex compounds with sulfate, including complex polymer and colloidal forms.

The lithium isotope separation (LIS) plays a vital role in development of nuclear industry. The liquid–liquid extraction technologies open up new possibilities for LIS. This work presents preliminary results of the study on the extractions and separation of 6Li/7Li by mixed system, comprising amino-derivatives of benzo-15-crown-5 (4AB), ionic liquid and anisole. 4AB was used as an extractant. The eparation factor (α) is 1.031 ± 0.001, and abundance of 6Li in loaded organic phase is 7.76%. Meanwhile, the reason why 4AB has better separation efficiency than B15C5 was explored brief by Fourier transform infrared (FT-IR) spectrum and quantum chemical calculations.

Seawater lithium stable isotope ratios, represented by δ 7 Li sw (‰), hold key information about the evolution of global climate and the carbon cycle over geologic time. Reconstructions based on foraminifera suggest an ∼9‰ increase in δ 7 Li sw over the past 60 m.y., interpreted as reflecting changes in the silicate weathering regime that may have contributed to global cooling over this time. However, culture experiments suggest that vital effects in foraminifers might cause varied δ 7 Li fractionation that could have affected past records. Thus, other archives are needed to determine whether the observed rise in foraminifer δ 7 Li values over the Cenozoic indeed reflects secular changes in δ 7 Li sw . Such archives would also open possibilities for robust determination of δ 7 Li sw deeper in geologic time. We analyzed δ 7 Li compositions in modern brachiopods ( n = 34) and found a relatively narrow range of +24.2 ‰ to +28.8‰ (mean = +26.8‰; 1σ = 0.5‰), similar to the range reported for inorganic calcite precipitated from seawater. These results confirm that brachiopods are good candidates for providing a representative record of δ 7 Li sw . We present data from fossil specimens dating from 65 Ma to ca. 700 ka, finding that fossilized brachiopods record a similar magnitude of change in δ 7 Li sw as foraminifers. These results are the first to corroborate the ∼9‰ increase in Cenozoic δ 7 Li sw and open possibilities for generating robust records of δ 7 Li sw in deep time, prior to foraminifer evolution.

We report [Li] and δ7Li values for a well-characterized suite of 52 geographically (165–184°W), compositionally (SiO2 = 46–70 wt.%), and temporally (0–38 Ma) diverse lavas and intrusive samples. The δ7Li in these rocks range from −0.7‰ to +14.2‰, with 32 of the 35 lavas and 12 of the 17 intrusive samples falling within the depleted mantle range (δ7Li +1.6 to +5.6‰), as sampled by mid-ocean ridge basalts (MORB). The δ7Li values of Aleutian lavas do not exhibit the spatial trends observed in other slab component tracers, nor do δ7Li values correlate with any slab component indicators, such as radiogenic isotopes, oxygen isotopes, or trace element ratios such as Cs/La and Th/La. The δ7Li values in Aleutian intrusions also do not exhibit temporal trends, however, an overall positive relationship exists between δ7Li and Th/Nd. Mixing models for δ7Li and 143Nd/144Nd values suggest that Aleutian samples within or above the MORB δ7Li range can be explained by addition of

New experimental data of angular distributions for the elastic and inelastic scattering of 10B ions by 6Li nuclei were obtained at the energy Elab(10B) = 51 MeV for the ground and excited 2.18 – 5.7 MeV states of 6Li and 0.7 – 6.56 MeV states of 10В. These elastic and inelastic scattering data and known from literature data of elastic scattering of 6Li ions by 10В nuclei at energy Elab(6Li) = 30 MeV were analyzed within coupled-reaction-channels method. The 6Li + 10B elastic and inelastic scattering data, spin reorientation of 6Li and 10В, as well as more important transfer reactions, were included in the channels-coupling scheme. The Woods - Saxon potential parameters, as well as 6Li and 10В deformation parameters, were deduced. The mechanisms of the 6Li + 10В inelastic scattering were studied within the model of collective nuclei excitations, the differences of the 6Li + 10В elastic scattering from using 6Li + 10В, 7Li + 10В and 6Li + 11В potentials were observed, the contributions of one- and two-step transfers were deduced using spectroscopic amplitudes for transfer particles calculated within the translation invariant shell model.

Description, Silicate weathering and physical erosion markedly increased during the rapid warming of the PETM, allowing climatic recovery., The Paleocene-Eocene Thermal Maximum (PETM; ~55.9 Ma) was a geologically rapid warming period associated with carbon release, which caused a marked increase in the hydrological cycle. Here, we use lithium (Li) isotopes to assess the global change in weathering regime, a critical carbon drawdown mechanism, across the PETM. We find a negative Li isotope excursion of ~3‰ in both global seawater (marine carbonates) and in local weathering inputs (detrital shales). This is consistent with a very large delivery of clays to the oceans or a shift in the weathering regime toward higher physical erosion rates and sediment fluxes. Our seawater records are best explained by increases in global erosion rates of ~2× to 3× over 100 ka, combined with model-derived weathering increases of 50 to 60% compared to prewarming values. Such increases in weathering and erosion would have supported enhanced carbon burial, as both carbonate and organic carbon, thereby stabilizing climate.

Understanding the mechanisms by which borosilicate glasses corrode in contact with aqueous solutions remains a challenge to the safety case for the geological disposal of vitrified high-level nuclear waste. Here, lithium isotope fingerprinting techniques were applied to the leachates of a simulant Magnox waste glass to probe the mechanisms of aqueous corrosion at both short and long timescales (6 hours to 464 days). Experiments took place at 40 and 90 °C to assess the consistency of the dissolution mechanisms across a range of commonly employed temperatures and the legitimacy of applying higher temperature experimental datasets to understand glass corrosion within a disposal facility at lower temperatures. Two competing release mechanisms were observed for lithium (diffusion and hydrolysis), and the relative proportions of these mechanisms changed through time. Leachates initially had lower δ7Li values than the pristine glass (−2.7‰ at 40 °C and −1.1‰ at 90 °C relative to the pristine glass) at both temperatures due to lithium leaching incongruently through diffusive processes. The greater offset between solution and solid at lower temperatures indicates a larger rate of diffusion (incongruent dissolution) relative to the rate of hydrolysis (congruent dissolution) at lower temperatures. The fraction of lithium released through diffusion relative to the fraction of lithium released through hydrolysis then increased at both temperatures with time up to 126 days, increasing from 0.47 and 0.22 at 6 hours to 0.66 and 0.41 at 126 days at 40 and 90 °C respectively. Subsequently, the fractions of lithium released through diffusion sharply decreased to 0.36 at 40 °C and 0.22 at 90 °C after 464 days, consistent with network hydrolysis coupled with secondary phase precipitation later controlling the long-term release of Li at both temperatures. Throughout the duration of the experiments (464 days) the δ7Li values in solution increased to 9.0‰ at 40 °C and 10.0‰ at 90 °C due to the formation of talc and montmorillonite phases at 40 °C and additional smectite phases at 90 °C. Further, no evidence for the formation of a diffusive barrier to the transport of Li within the alteration layers became apparent during the later stages of dissolution at either temperature. However, the fraction of lithium leached through diffusion was still significant throughout all stages of dissolution. Lithium isotope ratios in solution were correlated with the transition from a system which was increasingly dominated by lithium diffusion as the dissolution rate slowed to one which was controlled by hydrolysis coupled with secondary phase precipitation at long durations. Alongside elemental ratios in solution, these results were consistent with the same set of mechanisms governing dissolution across the temperature range studied.

Lithium isotopes are essential for nuclear energy, but new enrichment methods are required. In this study, we considered biotechnology as a possibility. We assessed the Li fractionation capabilities of three Chlorophyte strains: Chlamydomonas reinhardtii, Tetraselmis mediterranea, and a freshwater Chlorophyte, Desmodesmus sp. These species were cultured in Li containing media and were analysed just after inoculation and after 3, 12, and 27 days. Li mass was determined using a Inductively Coupled Plasma Mass Spectrometer, and the isotope compositions were measured on a Thermo Element XR Inductively Coupled Plasma Mass Spectrometer. The maximum Li capture was observed at day 27 with C. reinhardtii (31.66 µg/g). Desmodesmus sp. reached the greatest Li fractionation, (δ6 = 85.4‰). All strains fractionated preferentially towards 6Li. More studies are required to find fitter species and to establish the optimal conditions for Li capture and fractionation. Nevertheless, this is the first step for a microalgal nuclear biotechnology.

International audience; The demand for large and reliable datasets on isotopic composition has increased ingeochemistry and environmental sciences over recent years. We present an automated ionchromatographic separation method using a robotic pipetting arm, termed “ChemCobOne”, toreduce the time of sample separation. Its performance was tested for lithium isotope separationin geological reference materials using a single-step separation with HCl (0.2 mol l-1) and a 2-mlresin volume. This refined lithium purification method does not forfeit precision, accuracy orpurity compared with manual sample processing. In addition, a 7Li value for NASS-6 of 30.99 ±0.50‰ (2s) (95%CI = 0.14‰, n = 44) was determined and the first 7Li values for the granite rock

An experimental facility designed for separating lithium isotopes in plasma using the ion cyclotron resonance (ICR) method is described. High values of the lithium-isotope separation factor (α > 50) are attainable at the facility. A lithium-plasma source, the layout of cyclotron ion heating, and a collector system for lithium enriched and depleted with the 6Li isotope are described in detail. The methods used for measuring the parameters of the lithium plasma and the separation characteristics of the facility are also presented. The use of a “shadow,” i.e., a strip from the enriched-lithium collector without the lithium deposit on the depleted-lithium collector, for diagnostics of the plasma column rotation is noted. The projects for ICR facilities developed with our participation for separating isotopes of other chemical elements are briefly reported.

Due to the variety of applications of the isotopes in science and engineering as well as their strategic importance in national security, efficient and purity production is essential. 6Li and 7Li have a natural abundance of ~7.5% and 92.5%, respectively. Many of the ongoing lithium isotope separation processes have environmental issues, and the use of mercury is one of them and as part of the development of a new lithium isotope separation process, a model based on diffusion and migration processes on the influence of cell lengths and electrode materials, was used to simulate and predict the subtle differences in the concentration and the isotope ratio distribution with time. The three cell lengths used in the model simulation were 2 cm, 5 cm, and 10 cm, all with the two-compartments and two-electrodes configuration to study the influence of cell length on the separation process while the effect of electrode material on 7Li enrichment was investigated using graphite and LiCoO2 coated aluminum foil. The model predicted a higher maximum 6Li/7Li isotope ratio using LiCoO2 coated aluminum electrode and the time it takes for the Li ions to reach the cathode surface increases with the cell length under a second-order polynomial regression. The longer cell of 10 cm gives a better maximum separation factor and a larger volume of higher 6Li/7Li isotope ratio solution at the cost of the time it takes. Experimental tests were conducted in a 2 cm horizontal cell to investigate the influence of electrode materials and also the influence of alternating voltage on the lithium isotope separation. The obtained 7Li/6Li separation factor tests were: 1.010 and 1.008, respectively for the LiCoO2 anode and graphite anode material in the 3-hour long test while the shorter duration tests of 10 and 20 min yielded a high 7Li/6Li separation factor of 1.023 and 1.031, respectively. In addition, multi-stage tests were conducted in a vertical compartment cell for effective 7Li enrichment.

In this work we numerically calculate cross sections of the reactions 6Li ( n , n ′ γ ) 6Li and 7Li ( n , n ′ γ ) 7Li reactions in the region of neutron kinetic energy E n = 0.5 − 20 MeV. Neutron-nucleus interaction is defined in terms of the three-body problem wherein the target-nucleus is a bound two-body system. Dynamics in all two-body segments is described by the coupled Lippman-Schwinger equations with separable potentials. Free parameters of these potentials are chosen based on a fairly good description of elastic scattering phase shifts and radiation cross sections: t α → γ 7 Li, d α → γ 6 Li, n d → γ t . The system of three-body strongly interacting particles is described by the Faddeev equations. Radiative relaxation of the excited nucleus is effectively taken into account by the electromagnetic vertex inserted in the three-body scattering amplitude. Total cross sections and also poorly measured double differential cross sections of 6Li ( n , n ′ γ ) 6Li and 7Li ( n , n ′ γ ) 7Li are obtained and briefly analyzed.

With taking into account the β-factor value of the lithium ion aqua complex found earlier, the single stage extraction coefficient of isotope separation (α) of the 6Li–7Li pair has been calculated for the extraction system containing the benzo-15-crown-5–Li+ (H2O)Cl– complex in the organic phase, which corresponds to a real extraction process. Similar calculations have been carried out for other anions, as well as for various benzo-15-crown-5 derivatives with varying the number and type of donor atoms and different substituents in the benzene ring. Quantum-chemical calculations of the vibrational frequencies of the isotopic forms of the crown ether complex were performed using the Firefly program with the RHF/6-311++G** basis set. It has been shown that the isotope separation factor in this case is lower than in the case of the anhydrous benzo-15-crown-5–Li+Cl– complex and the model benzo-15-crown-5–Li+ (H2O) complex.

In this work, we discuss a far-off resonance optical dipole trap for cold lithium-7 atoms. A single optical trapping beam was produced by a continuous-wave fiber laser. Using our experimental data, we obtained important parameters of the trap, such as size of the cold atomic cloud, and evaluate the dipole potential and the rate of the trap losses. Information on temperature is acquired from observation of parametric resonances. We investigate the parametric resonances obtained with strong modulation of the trap potential and record superharmonics. We plan to prepare ultra-cold gas of highly-excited lithium atoms and study interactions between Rydberg atoms.

We have examined the effect of bifunctional group in the same cross-linkage degree on the Li isotope fractionation in the cation exchange reaction in the aqueous solutions ranging in temperature fr...

As a geochemical tracer in mantle studies, lithium isotopes play an important role in diffusion and fractionation in major mantle minerals. Olivine and its high-pressure phases, wadsleyite and ringwoodite, are considered to predominate in the upper mantle and transition zone on the earth. We carried out simulations of lithium isotopes’ diffusion and fractionation in Mg end member olivine and its high-pressure phases to learn the details of the signatures of lithium isotopes preserved in mantle materials. In this work, the diffusion and fractionation mechanisms between different lattice sites of lithium isotopes in forsterite (Mg2SiO4), wadsleyite (β-Mg2SiO4) and ringwoodite (γ-Mg2SiO4) at the atomic level are studied using empirical atomistic simulation techniques. It is found that Li can pass through the high-pressure phases (wadsleyite and ringwoodite) energetically much easier due to the low migration energy barriers via either substitutional or interstitial mechanism. The activation energy is high for Li diffusion along the interstitial path in the forsterite and decreases drastically with the assist of Mg vacancies. The temperature-dependent fractionation for two Li isotopes between two different lattice sites is calculated at the temperatures from 300 to 2500 K. This behavior generates the lighter Li storage in the near-surface mantle-derived rocks and provides insights into zoning and composition of lithium isotopes in olivine and its high-pressure phases.

Separation of lithium isotopes (6Li, 7Li) is a key technology to the development and utilization of nuclear energy. In this work, we present an efficient method to theoretically estimate the separation factors of 6Li/7Li in solvent extraction system based on Urey model. The approach was implemented by calculating the equilibrium separation factor of 6Li/7Li in the crown ether/Li aqueous solution [15-crown-5 (15C5), Benzo-15-crown-5 (B15C5), 12-crown-4 (12C4), Dicyclohexyl-18-Crown-6 (DH18C6)/LiX-H2O, X = Cl/I] exchange system utilizing the calculated harmonic vibration frequencies obtained by Density Functional Theory (DFT). The results showed that Urey model can correctly predict the direction of the 6Li/7Li separation as observed in the experiments. With this model, the underlying mechanisms driving the equilibrium isotope separation were elucidated further. The coordination structure of the Li complex played a dominant role in the separation of 6Li/7Li. For the solvent extraction system comprising crown ether phase and LiX aqueous solution, the crown ether with strong ability of excluding the hydrated water of Li gives a higher separation factor. The ways by which Li–O bonding of the Li-crown ether complex can be weakened, such as reducing the coordinated water molecules, applying high polar solvents, performing separation from Li salt with a softer anion, are helpful to improve the separation factor of 6Li/7Li at a fixed temperature. The lithium isotopic exchange is an exothermic reaction. Decreasing temperature favors the exchange reaction. This work is expected to provide guidance for the design of the exchanger and screening of the chemical exchange system for the separation of 6Li/7Li.

Lithium diffusion in LiMn2O4 pellets is studied by means of isotope exchange and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). A 6Li-enriched film deposited by Pulsed Laser Deposition (PLD) on a dense LiMn2O4 pellet with natural abundance of lithium isotopes is used to study the tracer diffusion of lithium. The measured profiles are analyzed by numerical models describing the 6Li tracer diffusion from the film into the pellet. Experiments in the Harrison type B regime of diffusion kinetics allow for the distinction and simultaneous determination of bulk and grain boundary diffusion coefficients. Changing the experimental conditions to reach Harrison type A behavior yields effective diffusion coefficients for lithium tracer diffusion in LiMn2O4. Activation energies for bulk and grain boundary diffusion were obtained from experiments at different temperatures. Our values are critically compared to previous studies.

In this study we have established a new method for in situ measurements of stable lithium (Li) isotope ratios at low Li concentration levels using UV-femtosecond laser ablation coupled with multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Highly precise in situ determination of Li isotope ratios is challenging due to low Li concentrations in most natural minerals and matrix effects typically occurring during the ablation process and in the ion source. Here we demonstrate that matrix-dependent isotope effects in the plasma can be largely suppressed by operating the plasma under cool conditions (900 W) and a laser beam which is focused ∼130 μm below the sample surface. Under such conditions, precise and accurate measurements of δ7Li with ∼2‰ (2σ) analytical uncertainty have been performed for various glass reference materials and olivine. Depending on the Li concentration of the investigated samples, detector combinations have been optimized in order to achieve the best precision. At Li concentrations ranging from 2 to 10 μg g−1 a combination of an ion counter for the determination of 6Li and a Faraday cup equipped with a 1013 Ω amplifier for 7Li has yielded the best precision. For Li concentrations > 10 μg g−1, Faraday cups equipped with a 1013 Ω amplifier for 6Li and a 1011 Ω amplifier for 7Li are recommended. Measurements applying a 1013 Ω amplifier require a tau correction due to the slower signal response of the amplifier. The accuracy of the here-established LA-MC-ICP-MS method was tested by comparing the results obtained for reference glasses that have been analyzed both in situ and with solution MC-ICP-MS (or other conventional methods, previously applied in other studies), and the results are overall in good agreement. The applicability to a zoned olivine phenocryst from the Massif Central volcanic region has been tested successfully.

This study develops and optimizes a new protocol to measure lithium isotope ratios using a single collector quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS) operated under hot plasma (1550 W) conditions with a sample–standard bracketing method. Our Q-ICP-MS method reduces sample consumption to 2.5 ng of Li and achieves a high long-term precision of 1.1‰ (2SD). This Q-ICP-MS method exhibits high matrix tolerance (Na/Li < 100), suitable for ng-sized and high-matrix geological samples. We also developed a dual-column system for Li separation, with large loading capacity (29.6 meq), complete recovery (∼100%) and satisfactory purification (Na/Li m m−1 < 1), as well as a fixed elution range for Li fractions (28–60 mL). This new chromatography method has been applied to chemically diverse materials, producing consistent results. In addition, we report the Li isotope compositions of 13 geostandards, and our measurements agree well with reported data within analytical uncertainties. This study documents that Li element concentration and Li isotope composition can be routinely measured using a single collector ICP-MS, which is convenient and commercially affordable for future Li isotope research across the fields of Earth and Environmental Sciences.

International audience; Lithium production has dramatically increased over the past decade, and the first cases of environmental Li pollution have been recently reported in urban and mining regions. While elevated Li concentrations may be toxic for living organisms, tools to monitor Li in the environment have not yet been developed. Consequently, its impact on key biota and human health is still poorly known. The present laboratory-based study shows that the soft tissues of blue mussels (Mytilus edulis) can be used to quantify Li contamination in coastal waters. Stable Li isotope ratios (7 Li/ 6 Li) measured in these soft tissues correlate positively with seawater Li concentrations and show precisely the threshold above which mussels shift their depuration mechanism. Combined with other data from the natural environment, the experimental results have profound implications for the fate of coastal ecosystems and shellfish consumption living under a high Li environmental level. We also highlight the need to develop innovative tools to extract Li from wastewaters before its release into rivers and, ultimately, the ocean.

Petrogenetic models for the genesis of Archean sanukitoids are diverse in the literature but most point to the initiation of plate tectonics and the construction of the first proto-continents during the Late Archean. These rocks include diorites, monzonites, monzodiorites, quartz monzodiorites, trachyandesites, granodiorites and tonalites, and are defined as having SiO2 = 55–60 wt%, Na2O + K2O = 6 wt%, MgO > 6 wt%, Mg# > 60, Ni–Cr > 100 ppm, Sr and Ba = 600–1800 ppm, chondrite-normalized Ce and Yb values of 80–250 and 4–10, respectively, and no Eu anomalies. Petrogenetic models include the partial melting of mantle peridotite previously metasomatized by fluids of crustal or mantle origin, partial melting of subducted slabs and assimilation of peridotite, and partial melting of undepleted peridotite with subsequent mixing with tonalite–trondhjemite–granodiorite (TTG) crustal partial melts and addition of carbonatite, all of which may or may not include subsequent differentiation by fractional crystallization. Here, extraordinary textural relations unequivocally show that at the Late Archean Otto stock, Abitibi, Canada, sanukitoids resulted from the assimilation of clinopyroxenite by monzonitic magmas and coeval magmatic–hydrothermal Na–K metasomatism. The metasomatized monzonites (± quartz), melanogranites, granodiorites, and sanukitoidal melanoporphyries were subsequently cut by swarms of lamprophyre dykes hosting a different set of hydrothermal alteration assemblages, including propylitic alteration, biotitization, chloritization, and pyritization, along with associated enrichments in Au. These alterations are shown to be associated with the nearby Cadillac–Larder Lake Fault Zone and the world-class Kirkland Lake gold deposit. The Li isotopic compositions of these rocks correlate with Au concentrations and range from magmatic values of ∼ +4 ‰ up to +10·4 ‰ in Na–K metasomatized and Au-depleted rocks, and from magmatic values of ∼4 ‰ down to 0·6 ‰ in rocks hosting propylitic, chloritic, and biotitic alteration and Au enrichments of up to 2·9 ppm Au.

An alternative method for lithium isotope amount ratio analysis based on a combination of high-resolution atomic absorption spectrometry and spectral data analysis by machine learning (ML) is proposed herein. It is based on the well-known isotope shift of approximately 15 pm for the electronic transition 22P←22S at around the wavelength of 670.8 nm, which can be measured by state-of-the-art high-resolution continuum source graphite furnace atomic absorption spectrometry. For isotope amount ratio analysis, a scalable tree boosting ML algorithm (XGBoost) was employed and calibrated using a set of samples with 6Li isotope amount fractions ranging from 0.06 to 0.99 mol mol−1, previously determined by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The calibration ML model was validated with two certified reference materials (LSVEC and IRMM-016). The procedure was applied to the isotope amount ratio determination of a set of stock chemicals (Li2CO3, LiNO3, LiCl, and LiOH) and a BAM candidate reference material, that is, LiNi1/3Mn1/3Co1/3O2 (NMC111) cathode material. The results of these determinations were compared with those obtained by MC-ICP-MS and found to be metrologically comparable and compatible. The residual bias was −1.8‰ and the precision obtained ranged from 1.9‰ to 6.2‰. This precision was sufficient to resolve naturally occurring variations, as demonstrated for samples ranging from approximately −3‰ to +15‰. To assess its suitability to technical applications, the NMC111 cathode candidate reference material was analyzed using high-resolution continuum source molecular absorption spectrometry with and without matrix purification. The results obtained were metrologically compatible with each other.

International audience; We illustrate two different, but complementary, applications of lithium (Li) isotope tracers for river-basin characterization at two different scales within the Loire River basin (LRB) in France. The first example deals with the behaviour of Li and the fractionation of its isotopes during river weathering at the basin scale of the LRB (117,800 km²). The wide δ7Li range (+5.0 to +13.3‰) in Loire basin streams, spatialized between the headwaters and the lowlands, is consistent with distinct weathering conditions and the distribution of Li from bedrock in the basin between the rivers and secondary mineral phases during water/rock interaction. Additionally, suspended sediments in the LRB streams are significantly 6Li enriched (7Li from -8.7 to -7.6‰) compared to average river waters that range from +5.0 to +13.3‰. The second example focuses on the smaller scale Egoutier watershed (13 km²), part of the LRB, which shows that Li isotopes can be useful for distinguishing between natural input and anthropogenic pollution, like effluents from a water treatment plant connected to a hospital. Overall, we confirm that Li isotopes cannot be used as lithological tracers for river waters. However, we did find that Li isotopes can be good tracers of weathering conditions and of anthropogenic sources in an urbanized watershed.

International audience