Lithium Isotopes Research Articles

Depth profile analysis and high-resolution surface mapping of lithium isotopes in solids using laser-induced breakdown spectroscopy (LIBS)

Lithium isotopic analysis is of interest in various fields from biology to energy. In addition to analytical methods commonly used for that purpose, a new complementary method for determining the spatial resolution of isotopic ratio in solid samples was previously developed: laser induced self-reversal isotopic spectrometry (LIBRIS), derived from laser-induced breakdown spectroscopy (LIBS). In this paper, we present a proof of concept of fast spatially-resolved quantitative isotopic analysis of lithium by LIBS both in depth (z resolution) and in configuration of high-resolution surface mapping (x and y resolution). First, a depth profile measurement where a 9% relative uncertainty on the 6Li isotopic ratio and 0.74 μm depth resolution is obtained. Then, we introduce the first high-resolution lithium isotopic mapping obtained by LIBS with a 3.3 μm lateral resolution and a typical 40% relative uncertainty on the 6Li isotopic ratio is obtained. Those results could be applied in the future to a large number of solid samples where fast information on the lithium isotopic distribution are needed, for instance in solid-state batteries development.

Effects of lithium isotopes on sodium/lithium co-transport and calcium efflux through the sodium/calcium/lithium exchanger in mitochondria.

The effects of lithium (Li) isotopes and their impact on biological processes have recently gained increased attention due to the significance of Li as a pharmacological agent and the potential that Li isotopic effects in neuroscience contexts may constitute a new example of quantum effects in biology. Previous studies have shown that the two Li isotopes, which differ in mass and nuclear spin, have unusual different effects in vivo and in vitro and, although some molecular targets for Li isotope fractionation have been proposed, it is not known whether those result in observable downstream neurophysiological effects. In this work we studied fluxes of Li+, sodium (Na+) and calcium (Ca2+) ions in the mitochondrial sodium/calcium/lithium exchanger (NCLX), the only transporter known with recognized specificity for Li+. We studied the effect of Li+ isotopes on Ca2+ efflux from heart mitochondria in comparison to natural Li+ and Na+ using Ca2+-induced fluorescence and investigated a possible Li isotope fractionation in mitochondria using inductively coupled plasma mass spectrometry (ICP-MS). Our fluorescence data indicate that Ca2+ efflux increases with higher concentrations of either Li+ or Na+. We found that the simultaneous presence of Li+ and Na+ increases Ca2+ efflux compared to Ca2+ efflux caused by the same concentration of Li+ alone. However, no differentiation in the Ca2+ efflux between the two Li+ isotopes was observed, either for Li+ alone or in mixtures of Li+ and Na+. Our ICP-MS data demonstrate that there is selectivity between Na+ and Li+ (greater Na+ than Li+ uptake) and, most interestingly, between the Li+ isotopes (greater 6Li+ than 7Li+ uptake) by the inner mitochondrial membrane. In summary, we observed no Li+ isotope differentiation for Ca2+ efflux in mitochondria via NCLX but found a Li+ isotope fractionation during Li+ uptake by mitochondria with NCLX active or blocked. Our results suggest that the transport of Li+ via NCLX is not the main pathway for Li+ isotope fractionation and that this differentiation does not affect Ca2+ efflux in mitochondria. Therefore, explaining the puzzling effects of Li+ isotopes observed in other contexts will require further investigation to identify the molecular targets for Li+ isotope differentiation.

Lithium systematics in the Krafla volcanic system: comparison between surface rhyolites and felsic cuttings from the Iceland deep drilling project -1 (IDDP-1)

The unexpected discovery of felsic magma by the Iceland Deep Drilling Project-1 (IDDP-1) in the Krafla volcanic system (KVS) presents a unique opportunity to investigate pre-eruptive lithium (Li) dynamics and establish a more direct connection between magma reservoirs and volcanic deposits. Our study provides new insights into Li abundances and isotope compositions in bulk-rock, minerals, and groundmass glass from rhyolitic lavas at KVS, encompassing various stages of groundmass crystallisation. Additionally, we examined felsic cuttings retrieved from the IDDP-1 well, comprising crystal-poor obsidian and crystal-bearing to -rich ‘felsite’ particles. Groundmass glasses from surface lavas show limited variability in K/Na, indicating limited secondary hydration of the glasses and that their Li contents seem to not be affected by this post-eruptive process. Lithium inventories in groundmass glasses and minerals within lavas exhibit variations consistent with the cooling history of the deposit, resembling patterns seen in Snake River Plain ignimbrites. Lithium contents of glassy rhyolitic lavas, whether bulk-rock (avg. 27.2 ± 3.1 μg/g) or groundmass glass (average 28.4 ± 4.7 μg/g), and their bulk isotopic compositions (avg. δ7Li =+ 4.4 ± 0.2‰) overlap with those observed in IDDP-1 obsidian cuts (avg. 24.9 μg/g Li in bulk, 28.6 ± 1.5 μg/g in groundmass glass, and δ7Li = 4.5 ± 0.2‰). Glassy lavas lacking spherulites may potentially preserve pristine magmatic Li element and isotope compositions, while areas with extensive groundmass crystallisation reveal Li enrichments in phenocrysts. Plagioclases in slowly cooled parts of the deposit record a two-fold increase in Li contents compared to plagioclase found in glassy counterparts, along with evidence of open-system degassing marked by heavier bulk Li isotope compositions and lower bulk Li contents of the crystallised lava portions (avg. δ7Li = +7.2 ± 0.1‰ and 7 ± 0.8 μg/g Li) relative to bulk glassy lithologies (avg. δ7Li = +4.1 ± 0.1‰ and 28 ± 2 μg/g Li). Partition coefficients derived from IDDP-1 cuts successfully predict Li inventories in vitrophyres of rhyolites on the surface of the KVS. Lithium isotope compositions of the crystal-rich IDDP-1 cuts are significantly heavier (avg. δ7Li = +7.2 ± 0.2‰) than lavas and IDDP-1 obsidian cuts, casting doubt on the notion that the IDDP-1 rhyolitic magma could result from the melting of felsite lenses in the KVS. Lithium contents in groundmass glasses within IDDP-1 crystal-rich cuts show higher Li contents (avg. 55.1–60.7 μg/g), correlating with the higher crystal content and an increase in other incompatible elements (avg. 250 μg/g Rb) relative to obsidian cuttings (avg. 75 μg/g Rb).

Electron Scattering from Stable and Exotic Li Isotopes

The nuclear shell model was used to investigate the bulk properties of lithium isotopes (6,7,8,9,11Li), i.e., the ground state density distributions and C0 and C2 components of charge form factors. The theoretical treatment was based on supposing that the Harmonic-oscillator (HO) potential governs the core nucleons while the valence nucleon(s) move through Hulthen potential. Such assumptions were applied for both stable and exotic lithium isotopes. The HO size parameters ( and ), the core radii ( ) and the attenuation parameters ( and ) were fixed to recreate the available empirical size radii for lithium isotopes under study.

Distinctive volcanic ash-rich lacustrine shale deposition related to chemical weathering intensity during the Late Triassic: Evidence from lithium contents and isotopes.

The Late Triassic Carnian Pluvial Episode (CPE) witnessed enormous climate change closely associated with volcanic activity. However, the coupling relationship between volcanic activity and climate change, which may be linked to chemical weathering, has not yet been fully uncovered. We used lithium contents and isotopes of volcanic ash (VA)-bearing lacustrine shale to constrain their deposition pathways and response to climate changes, i.e., weathering intensity, during the Late Triassic era. Elevated δ7Li (i.e., >2.5‰) and low Li contents (i.e., <65 microgram per gram) in shale likely document the direct depositing of volcanic lithium from airborne VA, which mainly inherited Earth's interior δ7Li signal. By contrast, shale yields markedly high lithium contents (i.e., >135 microgram per gram), alongside relatively low δ7Li (i.e., <0‰), likely implying waterborne VA dominated by intensified weathering under a super humidity climate. Hence, this study provides evidence for the differential VA-rich shale deposition model related to chemical weathering states synchronous with climate changes during the CPE period.

Experimental and theoretical constraints on lithium isotope fractionation during brine evaporation and halite precipitation

Marine evaporitic halite, precipitating from the advanced stage of extremely evaporated seawater, is the most common and abundant evaporitic mineral. The extent to which lithium (Li) is incorporated into evaporite halite during geological periods of massive halite deposition, and the mechanisms of incorporation, are both unknown. These are each important, however, for the quantification of the isotope effect of the evaporitic sink on δ7Liseawater, and for the potential use of halite as a recorder of seawater δ7Li. Here, new experimental data are presented for the Li fractionation factor for halite from an isothermal evaporation experiment (25∘C for 100 days) using marine-derived brine. The resultant solids were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to confirm the mineralogy and crystallinity of the product. Our results show that Li isotopes are not constant during the evaporation process implying that there must be a process that fractionates Li isotopes during halite precipitation. We suggest that this results from Li ionic substitution for sodium (Na) in crystalline halite, a scenario supported by ab-initio calculations, but we also show that Li within halite is predominantly present within fluid inclusions. Thus, the Li isotopic composition of halite is controlled by a mixture of Li within the fluid inclusions and Li that is incorporated into the halite crystalline structure. Overall, the brine becomes enriched in Li7 during evaporation due to the preferential incorporation of Li6 into chloride precipitates, and the evolution of δ7Librine is controlled by the precipitated mineral assemblage. The theoretical equilibrium fractionation factor 1000lnαmineral−fluid is -7.8▪ for Li-halite (LiNa26Cl27) at 25 C∘ at equilibrium, which is at the lower limit of Li isotope fractionation factors. Rayleigh fractionation models were fitted to the experimental data yielding a fractionation factor of -25▪3▪. The difference in Li isotope fractionation factor between brine and structurally bound Li may result from kinetic fractionation effects. This study presents a scenario highlighting that extensive halite deposits, formed over geological time in environments with relatively high Li concentration, could potentially impact the δ7Li values of seawater during that period, and place constraints on their utility as an archive for δ7Liseawater.

Lithium isotope fractionation during submarine hydrothermal alteration processes

River water and submarine hydrothermal fluids are the two primary sources of lithium (Li) input to the ocean. However, compared to well-documented weathering processes, the behavior of Li isotopes during hydrothermal alteration processes remains obscure. In this research, we investigated the Li isotopic compositions (δ7Li) of hydrothermally altered sediments from two IODP drilling cores (C0013 and C0014) in the Iheya North Knoll of the middle Okinawa Trough. The sediments, primarily altered from volcanic clasts, exhibit a pristine δ7Li value (5.2 ± 0.7 ‰) similar to that of MORB (3.7 ± 1 ‰). Intense hydrothermal activity led to the complete conversion of primary feldspars into phyllosilicates, predominantly Mg-chlorite, at site C0013 and in the middle and deep parts of C0014. The altered samples showed a depletion of 7Li (ranging in δ7Li from −10.0 ‰ to 4.2 ‰) compared to background sediment, indicating the preferential incorporation of 6Li during the formation of secondary minerals. Furthermore, both drilling sites exhibited increasing trends in δ7Li values with depth, with the deepest samples approaching the pristine δ7Li values of unaltered volcanic rock. These trends were attributed to the significant thermal gradients present at both sites. The temperature-dependent fractionation factor of Li isotopes allowed us to estimate the alteration temperature, which yielded temperature values consistent with those obtained using the δ18O geothermometer. This finding underscores the potential of Li isotopes as a novel geothermometer tool, although further calibration work is required. Based on our research findings, we developed a dissolution-precipitation model (based on mass balance) that establishes a relationship between the δ7Li values of altered solids and hydrothermal fluids, with the aim of elucidating the relatively limited variation observed in global submarine hydrothermal fluids (ranging from 1.6 ‰ to 11.0 ‰, with an averaged value of 5.9 ± 3.0 ‰, mean ± SD). This model quantitatively depicted the strong restriction of the Li concentration in hydrothermal fluids on their isotopic compositions, as high concentrations of Li in the fluids necessitate a substantial release of Li from the solid phase, causing the fluids' δ7Li values to approach that of the bedrock. Additionally, limited fractionation factors at high temperatures further constrain the variations in the fluids' δ7Li values. Model predictions also suggest that the reported δ7Li values of hydrothermal fluids have encompassed the potential δ7Li variation, providing supporting evidence for the assumption that δ7Li values of submarine hydrothermal fluids have exhibited insignificant variations throughout Earth's history.

Weathering Incongruence in Mountainous Mediterranean Climates Recorded by Stream Lithium Isotope Ratios

AbstractLithium isotope ratios (δ7Li) of rivers are increasingly serving as a diagnostic of the balance between chemical and physical weathering contributions to overall landscape denudation rates. Here, we show that intermediate weathering intensities and highly enriched stream δ7Li values typically associated with lowland floodplains can also describe small upland watersheds subject to cool, wet climates. This behavior is revealed by stream δ7Li between +22.4 and +23.5‰ within a Critical Zone observatory located in the Cévennes region of southern France, where dilute stream solute concentrations and significant atmospheric deposition otherwise mask evidence of incongruence. The water‐rock reaction pathways underlying this behavior are quantified through a multicomponent, isotope‐enabled reactive transport model. Using geochemical characterization of soil profiles, bedrock, and long‐term stream samples as constraints, we evolve the simulation from an initially unweathered granite to a steady state weathering profile which reflects the balance between (a) fluid infiltration and drainage and (b) bedrock uplift and soil erosion. Enriched stream δ7Li occurs because Li is strongly incorporated into actively precipitating secondary clay phases beyond what prior laboratory experiments have suggested. Chemical weathering incongruence is maintained despite relatively slow reaction rates and moderate clay accumulation due to a combination of two factors. First, reactive primary mineral phases persist across the weathering profile and effectively “shield” the secondary clays from resolubilization due to their greater solubility. Second, the clays accumulating in the near‐surface profile are relatively mature weathering byproducts. These factors promote characteristically low total dissolved solute export from the catchment despite significant input of exogenous dust.

The genesis of the Chakabeishan Li-(Be) pegmatite deposit in the northern Tibetan Plateau: Evidence from fluid inclusion and lithium isotope

The Chakabeishan (CKBS) deposit is a newly discovered pegmatite-type lithium-beryllium deposit in the northern Qaidam tectonic belt of the northern Tibet Plateau. In recent years, some studies have discussed the genesis of the deposit, but the topic remains unclear. This study constrains the genesis of CKBS deposit based on detailed field observations and mineralogical studies, and presents fluid inclusion data and Li isotopic compositions of Li-rich pegmatites and Li-poor pegmatites. The mineralization characteristics of CKBS deposit shows a trend from weak Be mineralization to Li mineralization in the south to north direction, which shows the magmatic differentiation feature. Four types of fluid inclusions are identified: (1) triphase crystal-bearing inclusions (type-1), (2) biphase CO2-rich inclusions (type-2), (3) biphase aqueous inclusions (type-3), and (4) monophase liquid inclusions (type-4). The Li-rich pegmatites mainly contain type-1 inclusions and type-2 inclusions, while Li-poor pegmatites contain type-3 inclusions and some type-4 inclusions. Microthermometric and Laser Raman spectroscopy analyses show that Li-rich pegmatites formed in a low to medium temperature (210.5 ∼ 381.3 ℃), low to medium salinity (5.23 ∼ 17.82 % NaCl equiv.) NaCl-H2O-CO2 system, whereas Li-poor pegmatites formed in a low to medium temperature (206.4 ∼ 413.4 ℃), low to medium salinity (1.05 ∼ 10.49 % NaCl equiv.) NaCl-H2O system, which indicates a fluid immiscibility between them. In addition, lithium is greatly enriched in Li-rich pegmatites under the positive effects of CO2. The Li-rich pegmatites display high Li content (8362.4 ∼ 15509.6 ppm) but low δ7Li values (1.61 ∼ 1.80 ‰). In contrast, the Li-poor pegmatites display low Li content (23.9 ∼ 231.9) but high δ7Li values (0.79 ∼ 12.32 ‰). This means that the lithium isotopic fractionation is produced by the melt-fluid immiscibility in CKBS deposit, in which a Li-rich system with rich water and poor silicate and a Li-poor system with poor water and rich silicate were formed during the process. Therefore, the CKBS deposit may have formed under the combined effects of magmatic differentiation, melt-fluid immiscibility, and fluid immiscibility.

Lithium isotope fractionation in highly evolved granites and associated magmatic-hydrothermal process: the case of the Xintianling granites in the Nanling Range, South China

ABSTRACT The highly evolved granites are closely associated with rare-metal mineralization. It is still debated whether the enrichment of rare metals is mainly controlled by magmatic or hydrothermal processes. Lithium is a fluid-mobile element that preferentially partitions to the fluid phase when the melt reaches H2O saturation, making the Li isotope system a powerful geochemical tool to record the potential melt-fluid interaction during magma evolution. This study addresses the issue of Li isotope fractionation in highly evolved fine syenogranites (FSGs) from the Xintianling pluton in the Nanling Range, South China. The Xintianling pluton consists of the coarse biotite monzogranites (CBMGs) and evolved FSGs. The identical Nd isotope data of the CBMGs (εNd(t) = -8.2–-8.8) and FSGs (εNd(t) = -7.9–-8.9) suggest that they were derived from the same crustal magma. The FSGs were derived from the highly evolved melts extracted from CBMGs through the fractionation of major rock-forming minerals. This is supported by the compositional shifts and validated by Rb, Sr, and Ba trace element modelling. Li isotopic analysis shows that highly evolved FSGs have heavier Li isotope compositions (δ7Li = 2.6–7.9 ‰) than the CBMGs (δ7Li = 0.1–1.9 ‰). Isotopic modelling, coupled with variations in Li concentrations in FSGs, suggests that diffusive kinetic fractionation by disequilibrium fluid exsolution during the late stage of the granitic magma evolution controls the Li isotope fractionation of the Xintianling granites. Rapid fluid exsolution not only modified the Li isotope composition of the FSGs but also transported the rare metals (e.g. W) and fluxing components (Li, F, and Cl), which resulted in the formation of the large Xintianling W deposits.

Assessment of Chalk as an Archive for the Lithium Isotope Composition of Seawater

AbstractThe understanding of silicate weathering and its role as a sink for atmospheric CO2 is important to get a better insight into how the Earth shifts from warm to cool climates. The lithium isotope composition (δ7Li) of marine carbonates can be used as a proxy to track the past chemical weathering of silicates. A high‐resolution δ7Li record would be helpful to evaluate the role of silicate weathering during the late Cretaceous climate cooling. Here, we assess chalk as a potential archive for reconstructing Late Cretaceous seawater Li isotope composition by comparing Maastrichtian chalk from Northern Germany (Hemmoor, Kronsmoor) to a Quaternary coccolith ooze from the Manihiki Plateau (Pacific Ocean) as a lithological analog to modern conditions. We observe a negative offset of 3.9 ± 0.6‰ for the coccolith ooze relative to the modern seawater Li isotope composition (+31.1 ± 0.3‰; 2SE; n = 54), a value that falls in the range of published offsets for modern core‐top samples and for brachiopod calcite. Further, the negative offset between the Li isotope compositions of Manihiki coccolith ooze and modern planktonic foraminifera is 2.3 ± 0.6‰. Although chalk represents a diagenetically altered modification of pelagic nannofossil ooze, manifested by changes in the composition of trace elements, we observe a consistent offset of Li isotope data between Maastrichtian chalk and Maastrichtian planktonic foraminiferal data (−1.4 ± 0. 5‰) that lies within the uncertainty of modern values. We therefore suggest that chalk can be used as a reliable archive for δ7Li reconstructions.

Multi-isotopic composition (Li and B isotopes) and hydrochemistry characterization of the Lakko Co Li-rich salt lake in Tibet, China: Origin and hydrological processes

A comprehensive comprehension of the origin and ore-forming process of lithium brine deposits is imperative prior to engaging in lithium resource exploration, development and utilization. Nevertheless, the provenance of lithium in salt lakes has always been controversial. The lithium and boron (Li and B) isotopes, which serve as discerning geochemical tracers, can facilitate the monitoring of geological processes and sources. In this study, we investigated the hydrochemistry, Li and B isotope characteristics of surface brine and recharge river samples collected from the Lakko Co on the Qinghai-Tibet Plateau in China. The dissolved Li concentrations range from 0.11 to 590.8 mg/L, δ7Li and δ11B values exhibit a range of 0.75∼8.11 ‰ and -18.29∼-4.01 ‰, respectively. Concentrations of elements such as Rb, and Cu are relatively high and exhibit a strong correlation with Li. Ions composition and content ratios indicate the deep origin of Li and B. The analysis of δ7Li and δ11B suggests that, apart from hot spring, weathering of surrounding rocks also contributes to the presence of Li and B. Besides, variations in δ11B values within the lake brine analysis may be attributed to the deposition of water Magnesite at the lake bottom. The findings suggest that the recharge water system and hot springs serve as the primary source of Li and B in Lakko Co. Additionally, the interaction between water and rock in the deep crust as well as chemical weathering in the shallow environment, significantly contribute to formation of Li-rich fluids. The transportation process is characterized by the precipitation of secondary mineral, resulting in an increase of δ7Li and δ11B. Furthermore, the presence of water Magnesite in the lake brine leads to fluctuations in δ11B. This investigation of the lake contributes to a more comprehensive understanding of the origins and mechanisms involved in the transportation and storage of lithium in lithium-rich salt lakes.

Lithium isotopes in water and regolith in a deep weathering profile reveal imbalances in Critical Zone fluxes

To trace Critical Zone processes and to quantify Li fluxes from one Critical Zone compartment into another, we investigated the Li concentration and isotopic composition (δ7Li) of time-series water samples (including subsurface flow, groundwater and creek water), vegetation, bedrock (including separated minerals from bedrock), and regolith (including exchangeable fraction and clay-sized fraction of regolith) in a temperate forested headwater catchment in the Black Forest, Conventwald, Germany. Our estimation of the Li budget shows that atmospheric deposition and biological processes played minor roles in the Li cycle relative to chemical weathering. All water samples (δ 7Li value of 6.5 to 20.4 ‰) were enriched in 7Li compared to bedrock (-1.3 ‰) and regolith (∼-1.7 ‰), but δ7Li differed between water pathways: δ7Li variations in subsurface flow, creek water and groundwater were controlled by conservative mixing, exchangeable pool buffering and Li incorporation/adsorption, respectively. Fractionated heavy Li isotopes in water samples resulted from the formation of secondary solids which preferentially incorporated 6Li, with the separated clay-sized fraction of the regolith exhibiting more negative δ7Li values (-5.4 to −3.5 ‰) than the bulk regolith (∼-1.7 ‰). However, Li in secondary solids only accounted for 8 ± 6 % of the total Li hosted in bulk regolith, and consequently δ7Li in soil did not differ significantly from δ 7Li in bedrock. This is unexpected considering water is continuously removing 7Li in preference over 6Li from regolith. Mass balance calculations applied at the catchment scale point to an irreconcilable imbalance with our data. On one hand, the regolith’s δ7Li values are not negative enough to balance the 7Li export by river water, and on the other hand Li in the riverine dissolved load only accounts for ∼ 30 % of the Li solubilized from regolith. Therefore, we suggest that there might be a “hidden export pathway” for Li at our site, possibly subsurface removal of fine particles enriched in 6Li. In light of increasingly frequent observations of such isotopic imbalances in the Critical Zone this phenomenon deserves increased attention.

Benzo-15-Crown-5 Functionalized Ionic Liquids with Enhanced Stability for Effective Separation of Lithium Isotopes: The Effect of Alkyl Chain Length

Benzo-15-Crown-5 Functionalized Ionic Liquids with Enhanced Stability for Effective Separation of Lithium Isotopes: The Effect of Alkyl Chain Length

SPIRAL MRI for in vivo lithium-7 imaging: a feasibility study in mice after oral lithium treatment

Lithium has been the frontline treatment for bipolar disorder for over 60 years. However, its mode of action and distribution in the brain is still incompletely understood. The primary isotope of lithium, lithium-7 (7Li), is a magnetic resonance (MR) active, spin-3/2 nucleus. However, its low MR sensitivity and the small brain size of mice make 7Li MR imaging (MRI) difficult in preclinical research. We tested four MRI sequences (FLASH, RARE, bSSFP, and SPIRAL) on lithium-containing phantoms, and bSSFP and SPIRAL on orally lithium-treated adult C57BL/6 mice. 7Li MR spectroscopy was acquired weekly at 9.4T to monitor the lithium uptake. The in vivo T1 relaxation time of 7Li was estimated in four mice. 4-h SPIRAL 7Li MRI was acquired in ten mice at a resolution of 2 × 2 × 3 mm3. SPIRAL MRI provided the highest signal-to-noise ratio (SNR) per unit acquisition time and the best image quality. We observed a non-homogeneous distribution of lithium in the mouse brain, with the highest concentrations in the cortex, ventricles, and basal brain regions. Almost no lithium signal was detected in the olfactory bulb and the cerebellum. We showed that in vivo 7Li MRI in mice is feasible, although with limited spatial resolution and SNR.

Electromigration separation of lithium isotopes with B12C4, B15C5 and B18C6 systems

In the aqueous-organic biphasic electromigration system, the larger cavity size of crown ethers, the weaker binding between crown ethers and Li+, and the lower dissociating voltage of complexes and initial voltage enriching 6Li in the catholyte.

Lithium Isotope Determination in Spodumene by fs‐LA‐MC‐ICP‐MS with Non‐Matrix‐Matched Calibration: Insights into ICP Operating Conditions and Data Evaluation

Lithium isotope measurement in spodumene by femtosecond LA‐MC‐ICP‐MS was investigated and the influence of plasma operating conditions and data reduction strategy on accuracy and precision was studied. It was found that “hot” plasma conditions led to an unstable baseline signal and substantial variations in the Li isotope ratios. By adding a constant amount of water to the carrier gas, a stable baseline was achieved and isotope ratios became reproducible and were consistent with data from solution‐based MC‐ICP‐MS. The resulting biases were within ± 0.51‰ and the reproducibility was better than 0.09‰. Comparison of Li isotope ratios resulting from different data evaluation schemes showed that the mean of the transient intensity ratios, integration of the entire or a user‐defined period of the ion signals resulted in good agreement with solution‐based data, while linear regression underestimated the Li isotope ratios. It was also found that “cool” plasma operation produced a stable baseline signal, but the Li isotope results were biased by up to ‐4.3%, irrespective of water introduction and the data evaluation scheme. With the optimised “hot‐wet” conditions, the Li isotope ratios in eleven spodumene materials were determined which successfully allowed distinguishing regional deposits and partially veins of the available samples.

Contrasting sources and enrichment mechanisms in lithium-rich salt lakes: A Li-H-O isotopic and geochemical study from northern Tibetan Plateau

Lithium (Li), a crucial mineral resource for modern high-tech industries, is notably abundant in the northern Tibetan Plateau, primarily within lithium-rich salt lakes. However, the exploration and development of these resources are hindered due to an incomplete understanding of their nature and origin. Here we present results from a comprehensive study on the hydrochemical parameters, whole-rock geochemistry, H-O isotopes, and Li concentrations in surface brine, river water, geothermal springs, and associated rocks from two representative lithium-enriched salt lakes, the Laguo Co (LGC) and Cangmu Co (CMC) in Tibet to understand the genetic mechanisms. Our water-salt balance calculations and H-O isotopic analysis reveal that Li in LGC and CMC primarily originates from the Suomei Zangbo (SMZB, ∼91%) and Donglong Zangbo (DLZB, ∼75%) rivers, respectively. It is estimated that the LGC and CMC took a minimum of 6.0 ka and 3.0 ka to accumulate their current lithium resources, respectively. The distinct geological characteristics reflect evolutionary differences between the two lakes, suggesting diverse lithium sources and enrichment processes. The high lithium ion concentration and light lithium isotope composition in the SMZB river waters indicate the genetic relationship with lithium-enriched geothermal springs in the Tibetan Plateau. Our results suggest that lithium in the LGC originates from lithium-enriched geothermal springs and is primarily supplied through the small-scale SMZB river. In contrast, the formation and evolution of CMC are influenced by the northern Lunggar rifts, receiving a prolonged and stable input from the DLZB, resulting in high lithium concentrations and isotopic values. The absence of lithium-enriched geothermal springs and the prevalence of silicate rocks in the CMC catchment suggest that lithium may be sourced from the weathering of silicate rocks, such as granitic pegmatite veins containing lithium-rich beryl, widely distributed in the upstream area of DLZB. The forward modeling approach, quantifying the contribution fractions of different reservoirs (atmospheric precipitation, silicate, carbonate, and evaporite), indicates that the distinct lithium concentrations in the mainstream (>1 mg/L) and tributaries (<0.1 mg/L) are positively correlated with the ratio of silicate contributions to carbonate contributions, suggesting that dissolved lithium in river waters primarily originates from the weathering and dissolution of silicate rocks. The distinct sources and enrichment mechanisms of lithium in these two salt lakes are attributed to various evolutionary processes, topographical features, hydrological factors, fundamental geological settings, and tectonic histories, despite their spatial proximity. Furthermore, our study highlights the significant role of rivers in the formation of young salt lakes, in addition to geothermal springs.

Composition and constraints of lithium isotopes in cryoconite from various remote glacier areas of the Tibetan Plateau

Lithium isotope is one of the most promising indicators for the study of continental silicate weathering, and lithium concentrations and its isotopic compositions in earth surface can provide a better understanding of the geochemical behavior and isotopic fractionation during weathering and erosion. This work focused on the composition and distribution of Li isotope in cryoconite deposited on various glacier areas in a large range of the Tibetan Plateau and surroundings, as well as its implications for cryoconite dust provenances. Results showed that δ7Li in cryoconite varied within the same order of magnitude (−2.14 ‰-7.74 ‰), which is characterized by geographic distribution of higher δ7Li value of cryoconite in northern glaciers (e.g. Yuzhufeng Glacier), and lower δ7Li value in southern glaciers. In comparison with other global materials, the cryoconite dust shows a lighter δ7Li isotopic composition due to constraints of climatic conditions and land surface weathering intensity. Compared with dust materials in the surrounding Asian dust sources (e.g. large deserts and Gobi), we find that, the primary sources of Li isotope in cryoconite of the northern locations were from both local dust/soils of the TP surface and the surrounding large deserts. Moreover, the products of anthropogenic activities (e.g. coal-burning) may also influence the isotopic composition of the cryoconite dust, and Li isotope may serve as potential tracers of anthropogenic source activities. Therefore, this work provides a complete view of the composition and distribution of Lithium isotopes in cryoconite from various glacier areas of the Tibetan Plateau, and the research significance of its transport processes and source constraints of Li isotopes in cryoconite is proposed.

Electromigration separation of lithium isotopes: The effect of ionic liquid ratios

This study is based on the system of “anodic aqueous solution | crown ether-ionic liquid organic solution | cathodic aqueous solution”, the influence of ionic liquid ratio in organic solution under different voltages on Li+ transport and lithium isotope separation was investigated. It is found that ionic liquids have multiple roles. In addition to improving the conductivity of organic solutions and enhancing Li+ transport capacity between aqueous solution and organic solution through ion exchange. Ionic liquids are even to realize the migration of lithium ions from aqueous solution to organic solution through solvation. There is an obvious synergistic enhancement between ionic liquid solvation and electric field. Based on this, three types of Li+ transport across the aqueous-organic interface are proposed. The influencing mechanism of ionic liquid ratio, voltage on Li+ migration ratio and lithium isotope separation is discussed in detail.