Lithium Isotopes Research Articles

Purification of High Aluminum Content Samples for Rapid and Precise Analysis of Lithium Isotopes

Purification of High Aluminum Content Samples for Rapid and Precise Analysis of Lithium Isotopes

Ab initio single-neutron spectroscopic overlaps in lithium isotopes

<i>Ab initio</i> single-neutron spectroscopic overlaps in lithium isotopes

Evolution of the alpine Critical Zone since the Last Glacial Period using Li isotopes from lake sediments

Comprehending and predicting the way humans affect the Earth's Critical Zone remains a challenge. An understanding of the past changes resulting from human and non-human influences in the dynamics of the Critical Zone is crucial. Here, we use a retrospective approach to address this question based on a new lithium (Li) isotope record from the Late Glacial Period to the present from a pre-Alpine lake sediment sequence (Lake La Thuile, France). Coupled with the lake sediment archive, the investigation of present-day soils in the lake catchment suggests that lake sediments are not necessarily recording the erosoin of topsoil in the catchment. Our findings indicate that soil particles can be sorted during transportation to the lake, with finer particles being preferentially mobilized, highlighting the influence of fine particle transport on the Li isotope signature of soils and lake sediments. Characterized by low Li isotope signatures, changes in weathering signatures in lake sediments can be amplified by the combined effect of soil development and selective transport. In the La Thuile catchment, soil development was limited during the Late Glacial Period, whereas it became a dominant process during the Holocene climatic optimum together with enhanced selective transport of fine particles. Human activities since 3,000–4,000 yr cal BP induced a strong perturbation hindering both soil formation and selective transport by reinforcing erosion rates. After a period of topsoil destruction caused by intense deforestation and agriculture, lake Li isotopes record the evolution of soil profiles associated with changes in agricultural practices.

Fluid evolution and ore genesis of the Weilasituo Li-Sn-Cu-Zn polymetallic deposit in Inner Mongolia: Evidence from fluid inclusion and C-H-O-Li isotopes

The Weilasituo Li-Sn-Cu-Zn polymetallic deposit is located in the southwestern Great Xing'an Range (GXR), and crypto-explosive breccia-type and hydrothermal vein-type mineralization are developed in the mining area. With the Early Cretaceous amazonite granite as the mineralization center, the greisen-type Li(-Rb) mineralization is developed in the crypto-explosive breccia pipe above the granite, and the quartz vein-type Sn(-W-Mo) and Cu-Zn(-Ag) mineralization is successively developed in the surrounding Paleoproterozoic Xilinguole complex, forming mineralization zoning. The polymetallic metallogeny comprises early Li (Rb) through Sn(-W-Mo) to late Cu-Zn(-Ag) mineralization, and can be divided into six stages: (I) zinnwaldite–topaz–fluorite, (II) quartz–arsenopyrite–cassiterite–sphalerite–wolframite, (III) quartz–molybdenite–polymetallic sulfides, (IV) quartz–arsenopyrite–pyrite–chalcopyrite, (V) quartz–chalcopyrite–pyrrhotite–sphalerite–galena ± pyrite, and (VI) quartz–calcite–fluorite.Fluid inclusions (FIs) in the zinnwaldite, topaz and fluorite of Li(-Rb) ore phase contain high-temperature medium-salinity (348–404℃; 5.09–9.60 wt%) vapor–liquid two–phase aqueous type (vapor–liquid ratio: 35–70 %), similar to intermediate-density (ID) type FIs, and represent a single-phase fluid directly exsolved from the magma; FIs in the Sn(-W-Mo) ore phase quartz contain daughter mineral-bearing three-phase (SVL), vapor (V), vapor-rich two-phase aqueous (LV) and liquid-rich two-phase aqueous (VL) type, reflecting fluid boiling; FIs in the Cu-Zn(-Ag) ore phase quartz contain CH4 ± CO2 two-phase FIs and VL-type FIs, indicating fluid immiscibility. Lithium isotope data show that the Li ore-forming material was crustal derived, while H-O isotope data indicate that the ore fluid was derived from magmatic water and mixed with meteoric water in the late Cu-Zn(-Ag) ore phase; Carbon isotope data suggest that the CH4 and CO2 in the FIs were sourced from the fluid-rock reaction between the hydrothermal fluid and with the Xilinguole Complex graphite-bearing wallrocks. Raman spectroscopy shows that stage Ⅱ-Ⅴ FIs contain CH4 and CO2, whose content increased markedly from the Sn(-W-Mo) to Cu-Zn(-Ag) stage, indicating that CH4 and CO2 are enriched continuously with fluid migration and fluid-rock reaction.We conclude tha the initial single-phase ID Li-Rb-W-Sn-rich fluid was exsolved from the magma, and formed the Li(-Rb) mineralization in the crypto-explosive breccia pipe as the temperature dropped. Subsequently, the fluid entered the faults and the pressure dropped, causing fluid boiling, and triggered the proximal Sn(-W-Mo) vein-type mineralization. With the fluid migration and more water–rock reaction, CH4 and CO2 are continuously enriched and fluid immiscibility occurred, forming the distal Cu-Zn(-Ag) vein-type mineralization.

Assessing hydrological controls on the lithium isotope weathering tracer

To investigate the impact of riverine discharge and weathering intensity on lithium isotopes (δ7Li) in a mono-lithological terrain, this study examines the dissolved load and leached suspended load (exchangeable, oxide, and clay fractions) from Icelandic rivers spanning a wide range of discharge, weathering rates, and weathering intensity. The δ7Lidissolved co-varies inversely with the discharge, confirming that water-rock interaction time is a primary control on the secondary mineral formation that fractionates Li isotopes. The “boomerang” shape observed in global rivers between the weathering intensity (i.e. W/D = weathering rate/denudation rate) and δ7Lidissolved also exists for these basaltic rivers at low to medium W/D. However, these rivers do not extend to such low δ7Lidissolved values as seen in the global compilation at low W/D, indicating that there is a lithological control on this relationship arising from the type of the lithology-specific secondary minerals forming and their precipitation rates. In addition, the Δ7Lix-dissolved between each leached solid phase and the dissolved load also co-varies with discharge. At low discharge (long water-rock interaction times), Δ7Lix-dissolved values agree with experimentally-determined equilibrium values, whereas less fractionated values are observed at higher discharge (shorter water-rock interaction times). As a result, there is a different relationship between W/D and Δ7Liclay-source in this basaltic terrain than previously reported from global multi-lithological river sediment samples, with clay leachates from Iceland more closely mimicking the boomerang shape of the dissolved load. However, the relationship between δ7Li and weathering processes is complicated because the fractionation between the clay fraction and the dissolved load is not constant but varies with both W/D and discharge. Overall, this study confirms the utility of Li isotopes as a tracer of modern and palaeo-weathering processes, and also has important implications for the specific interpretations of detrital δ7Li values, which may be more sensitive to weathering parameters than previously thought.

The influence of secondary weathering processes on dissolved nickel isotope compositions under cold climatic conditions – Observations from the Mackenzie Basin

Nickel (Ni) and its stable isotope signature (δ60Ni) have recently gained momentum as a tracer of nutrient cycling in the modern and past oceans. A robust understanding of Ni isotope cycling in the ocean rests on an accurate understanding of the Ni sources and sinks to and from the oceans. In particular, rivers, which are the dominant Ni source to the oceans, show significant variation in Ni isotopes compared to rocks, thought to reflect variable extents of formation of secondary phases that scavenge light Ni isotopes. The current estimate of the global isotope composition of riverine Ni is based on a few large rivers in warm climates, thus preventing the assessment of a potential climatic control on the Ni isotope flux to the ocean. In this contribution, we investigate the Ni elemental and isotope signatures of river catchments in cold climates, namely the Mackenzie Basin tributaries (Canada) and two rivers, the Nass and Skeena, draining the Western Cordillera.The river solid load in the Mackenzie Basin shows almost no resolvable variation in terms of Ni abundances and Ni isotopes, which are similar to silicate rocks. Furthermore, dissolved Ni and Ni isotopes do not show any relationship with source tracers. This suggests a minimal source control on variations in riverine Ni. This result is particularly intriguing as riverine chemistry in the Mackenzie Basin is often dominated by lithological controls, including rocks other than silicate, such as carbonate and black shale. Instead, the variations in dissolved Ni isotopes are related to the removal of dissolved Ni, reflecting the dominant control by secondary weathering processes. The Ni isotope fingerprint of these secondary weathering processes reflects Ni scavenging into metal oxides, consistent with the literature. The data presented here and literature data show that dissolved Ni and lithium isotopes (a tracer of clay formation) exhibit contrasting patterns between the Mackenzie and the Amazon basins. This suggests that climatic conditions might couple or decouple the formation of metal oxide and clay. In addition, the Ni isotope signatures of the river dissolved load vary with the specific weathering intensity of Ni (the fraction of riverine Ni exported as dissolved species). At high specific weathering intensity of Ni, the Ni isotope signature reflects that of silicate, consistent with the congruent release of Ni from the weathering of silicate. Lower specific weathering intensities of Ni are associated with heavier Ni isotope signatures, suggesting greater scavenging of Ni onto secondary metal oxide. Finally, at the lowest Ni weathering intensity, the dissolved Ni isotope composition is lower again, potentially implying limited metal oxide formation under such conditions. Therefore, and though more data are required to confirm the hypothesis from this initial data, while climate might play a role in the relative rate of Li- and Ni- scavenging phase formation, the specific weathering intensity of Ni may be more significant in controlling dissolved Ni isotope composition.

Carbonate lithium isotope systematics indicate cooling triggered mass extinction during the Frasnian-Famennian transition

We present comprehensive Li-C-Sr isotopic studies on two classic marine carbonate sections (Yangdi and Dongcun) transecting the Late Devonian Frasnian-Famennian (FF) boundary from South China to constrain the causes of the FF mass extinction. Both sections show positive Li and C isotopic excursions in carbonate and unchanged conodont 87Sr/86Sr ratios across the FF boundary. Low Li/Ca and Sr/Ca ratios, but heavy Li isotope composition (δ7Li) of the Dongcun section indicate possible diagenetic alteration on carbonate Li isotopic records. By contrast, the Yangdi section records more primary seawater δ7Li signal, showing a ∼ 2 ‰ positive excursion before the FF boundary, although reconstructed paleo-seawater δ7Li values (from 11.8 ± 1.4‰ to 13.8 ± 1.4‰) are lower than modern times. Combined box model with Monte Carlo simulation demonstrates that low seawater δ7Li requires low riverine δ7Li and small effective Li isotopic fractionation by marine sinks (Δ7Lisw-ms). The latter is likely due to high silicon concentration in the paleo-seawater and rapid formation of clay minerals. Positive δ7Li excursion but invariant 87Sr/86Sr ratios in the seawater are related to attenuated continental weathering (reduced riverine fluxes but increased riverine δ7Li), and enlarged effective Δ7Lisw-ms. Based on the present data we suggest that rapid climate cooling is responsible for the weathering transition and must have exerted significant influence on the marine environment. Global climate cooling weakens seawater stratification while intensifying oceanic circulation and upwelling, resulting in enhanced primary productivity, precipitation of the Kellwasser black shales and a remarkable positive C isotopic excursion in carbonate. Additionally, rapid climate cooling around the FF boundary has significantly threatened the ecological system and finally triggered mass extinction especially for the faunas adapted to warm temperatures.

Lithium isotopic systematics and numerical simulation for highly-fractionated granite-pegmatite system: Implications for the pegmatite-type rare-metal mineralization

Lithium (Li) isotope behavior during fractionation of highly-evolved granitic pegmatites and associated rare metal mineralization remains unclear, especially concerning the relative importance of magmatic versus metasomatic processes. In this study, we investigated the geochemistry and Li isotopes of the giant Renli-Chuanziyuan lithium-niobium-tantalum (Li-Nb-Ta) deposit in the Mufushan batholith (South China). We found that muscovite granite in the Mufushan complex can be divided into two groups (high-Li and low-Li). δ7Li value of the high-Li and low-Li group increases and decreases, respectively, with increasing Li content, which is likely resulted from fractional crystallization and/or magmatic volatile phase (MVP) exsolution. The MVP exsolution began with the solidification of muscovite granite, as evidenced by the zoned micas. The Li isotope fractionation, modeled by Rayleigh distillation during MVP exsolution, is consistent with the δ7Li value of Li-poor pegmatite, indicating that MVP exsolution is related to the pegmatite formation.The Mufushan Li-poor and Li-rich pegmatites have very high and low δ7Li value, respectively. Based on the Δ7Li(bulk-mica) value and numerical simulation, we suggest that the pegmatite formation at Mufushan could be linked to extensive MVP accumulation, while the different Li elemental and isotopic compositions of the two types of pegmatite are probably caused by MVP migration. In fact, published granite-pegmatite data worldwide also show negative Li vs. δ7Li correlation, indicating that such MVP exsolution, accumulation and migration are probably a common phenomenon for evolution of granitic pegmatite. Therefore, the different Li isotopes and Li-Rb-Cs proportion of Li-poor and Li-rich pegmatites indicate that MVP exsolution, migration and accumulation are key to rare metals enrichment and distinguish various types of rare-metal mineralization (Li and Nb-Ta).

Lithium isotope systematics of methane-seep carbonates as an archive of fluid origins and flow rates

Fluid sources and flow rates at methane seeps control gas hydrate formation, and are potentially archived in authigenic carbonates. Lithium (Li) in seeping fluids exhibits a broad range of isotopic fractionation during its ascent to the seafloor, providing information on temperatures and flow rates of the fluids. To test the applicability of Li isotopes as a fluid tracer in authigenic carbonates, this study investigates the element and Li isotope composition of methane-seep carbonates collected from the Black Sea and the Japan Sea. The Li/Ca ratios and δ7Li values of the aragonite-rich and calcite-rich samples (10–60 μmol mol−1 and 3.5–15.6‰; 21–142 μmol mol−1 and 8.3–24.4‰, respectively) are distinct from those in carbonates precipitated from seawater, and indicate an input of deep-seated fluids enriched in 6Li. After correcting for a minor admixture of clay-bound Li, the Li/Ca ratios and δ7Li values of the parent fluids were estimated to be 2400–11 000 μmol mol−1 and 17.2–34.5‰, respectively. Variations in the estimated values cannot be explained by fluid mixing alone, but rather reflect the isotopic fractionation caused by interaction of the deep fluids with secondary minerals during fluid ascent. The δ7Lifluid values as low as 17.2‰ for the Japan Sea carbonates indicate a deep fluid source with estimated temperatures of >26 °C derived from >250 m below the seafloor. Reaction-transport modeling shows that the deep fluid was transported to the zone of carbonate precipitation with advection rates of ≥10−2 cm yr−1. Higher advection rates were indicated for the Japan Sea fluids than for Black Sea fluids, probably due to a larger contribution of dissolved methane to hydrate formation. Spatiotemporal variations in fluid sources and advection rates were indicated by distinct (Li/Ca)fluid and δ7Lifluid values between the carbonates and pore fluids. The Li isotope systematics of seep carbonates are a potent indicator of the origin and flow rate of deep-seated fluids and their spatiotemporal variability, which is explored herein in detail for the first time.

Widespread clay authigenesis and highly congruent silicate weathering in the Marinoan aftermath

The termination of the Cryogenian period marks a transition from an extreme ice- to a greenhouse climate, likely initiated by increased atmospheric CO2, however uncertainties persist on continental weathering regarding this climate transition. Here we present paired lithium isotope data from carbonate (δ7Licarb) and carbonate-hosted silicate (δ7Lisili) components of the Marinoan cap carbonates to constrain C and Si cycles in the deglacial period. We find that the silicate component of cap carbonates is dominated by marine authigenic clays with minor contributions from terrestrially detrital materials and oxides. Built from δ7Lisili data, large variations of seawater δ7Li suggest a heterogeneous marine Li reservoir due to a stratified ocean in the deglacial period. Overall, widespread clay authigenesis and low seawater δ7Li values indicate active carbon-silicon cycling and congruent silicate weathering due to warm climate and exposure of fresh rock surface in the Marinoan aftermath, which promotes the deposition of cap carbonates and stabilization of Earth's surface environment.

Contrasting riverine K and Li isotope signatures during silicate weathering in the southeastern Tibetan Plateau

Mountain uplift produces steep slopes and rapid erosion rates, and hence exposes more silicate rocks to weathering and accelerates the drawdown of atmospheric CO2, driving global cooling over the Cenozoic. Riverine potassium (K) and lithium (Li) isotopes are two promising proxies for silicate weathering because the isotopes fractionate during secondary mineral formation associated with weathering and these two elements are highly enriched in silicate rocks. This study explores similarity and difference between K and Li isotope behaviors during weathering across the Lancang River in the southeastern Tibetan Plateau, in order to evaluate the role of these two isotopes in tracing silicate weathering in tectonically active mountains. Dissolved K and Li in the Lancang River mainstream are mainly derived from the dissolution of silicates. River waters are enriched in the heavy isotope of K (−0.35‰ to +0.05‰) and Li (+7.1‰ to +20.4‰) relative to suspended sediments (−0.56‰ to −0.42‰ and −2.3‰ to 0‰, respectively), and the element partitioning between dissolved and suspended loads controls dissolved δ7Li and δ41K values. Interesting, dissolved δ7Li and δ41K show the opposite evolution trends toward downstream. As the weathering intensity increases downstream (higher Si/(Na + K)⁎ ratios), the dissolved δ7Li values increase from 7.4‰ to 13.6‰, whereas dissolved δ41K values decrease from −0.04‰ to −0.26‰. Compared to its headwater with limited weathering, more secondary minerals (e.g., clays) are formed in the lower reaches (e.g., floodplains) with low physical erosion rates and high annual precipitation, driving more 6Li incorporated into clays, thus high dissolved δ7Li values downstream. While dissolved δ41K values and the fraction of 39K incorporated into secondary minerals are low in floodplains, this is consistent with observations that illite is a main K-bearing phase among clay minerals, and its content in the clay fraction in river sediment decreases as weathering intensity increases. Our study further supported that the increase in Cenozoic seawater δ7Li is related to weathering in floodplains rather than weathering of mountains, whereas K isotope fractionation mainly occurs in mountain regions. If Cenozoic seawater δ41K rise, as with δ7Li change, weathering at higher elevation may exerts more effect on high riverine and seawater δ41K values. This study improves our knowledge of K-Li isotope behaviors during present-day silicate weathering, and the response of K-Li isotopes in sedimentary archives to silicate weathering over geological time.

Lithium isotope systematics and water/rock interactions in a shallow-water hydrothermal system at Milos Island, Greece

The active venting fluids of Milos Island, located within the southern Aegean Sea, belong to a shallow-water hydrothermal system (< 200 m depth) that shows chemical compositions and evolution processes comparable to those of mid-ocean ridges (MOR). In this study, we analyze Li and δ7Li in 69 vent water samples, grouped into two types based on their salt content. The low-Cl end-member (EM) Cave fluids show a relatively high Li content (0.39–0.54 mM) with MORB-like δ7Li (∼4.5 ‰, MORB = 3.7 ‰) compared to that of seawater, and the high-Cl brine fluids contain remarkably high Li (6.14–10.6 mM) and variable δ7Li (1.4–8.7 ‰). The latter fluids may have derived from metamorphic basement modified by seawater interactions at ∼300 °C. A scenario using a steady-state dissolution/precipitation model can generate consistent Li and δ7Li patterns, where linear correlations of Cl and Li suggest phase separation occurred after water/rock interaction at depth. On the contrary, no significant δ7Li variation in most Milos fluids suggests limited isotopic fractionation occurred during phase separation. More importantly, the detected Li enrichment in the high-Cl fluids implies a large Li flux, ∼3.4 × 107 mol/yr, to the ocean from the Milos system. Assuming that 10% of the world's shallow-water systems discovered to date have similar Li outputs to those of Milos, this Li flux would represent ∼1.8% of MOR hydrothermal fluxes which is on the order of ∼13 × 109 mol/yr. These results emphasize the importance of Li flux derived from shallow-water hydrothermal systems, which should not be excluded from the calculation of the marine Li budget and its impact on the global silicate weathering cycles.

Effect of the Substrate and the Morphology on Electrochemical Separation of Lithium Isotopes: Insights from DFT

Effect of the Substrate and the Morphology on Electrochemical Separation of Lithium Isotopes: Insights from DFT

Lithium isotope separation by precipitation method coupled with solvent extraction with 1-Hydroxy-4-(p-toluidino) anthraquinone

This paper reported a novel chelating agent and a green precipitation-extraction separation strategy for lithium isotope enrichment. 1-Hydroxy-4-(p-toluidino) anthraquinone and anisole were used as chelating agent and diluent, respectively. Three phases including organic phase, aqueous phase and precipitation could be preparated. The experiment indicated that excess sodium hydroxide was helpful to promote the single-stage precipitation rate and equilibrium time. The isotope result indicated that 6Li was concentrated in the aqueous phase and 7Li was concentrated in precipitation phase. The maximum single-stage lithium isotope speration factor reached to 1.013 ± 0.001. By doing thermodynamic analysis of the reaction, the free energy change (ΔG), enthalpy change (ΔH) and entropy change(ΔS) of the separation process were −8.97 J mol−1, −21.37 J mol−1 and −0.0438 J mol−1 K−1 at 283 K. The results of DFT simulation and wave function analysis indicated that a lithium ion combined with a chelating agent anion formed a stable six-member ring between two oxygen, which was more stable than sodium ions combined with chelating agent anions (the Gibbs free energy of the lithium ions reaction was more negative). As interaction analysis result showed, the Li-O bond in complex interaction was significantly stronger than the Li-O bond interaction in aqueous phase, which was the theroy that led to the enrichment of 7Li in organic phase. In the activated carbon treatment experiment, it was found that part of lithium chelator solved in aqueous phase, which resulted in that the lithium abundance of aqueous phase hardly changed. In order to increase the abundance of 6Li in aqueous phase, it is necessary to add adjuvant to reduce the water solubility of lithium chelate. Overall, an economical and environmental-friendly precipitation method with a certain application prospect for lithium isotope separation was proposed, and the direction of improving the separation performance was pointed out in this paper.

Lithium isotopes differentially modify mitochondrial amorphous calcium phosphate cluster size distribution and calcium capacity.

Lithium is commonly prescribed as a mood stabilizer in a variety of mental health conditions, yet its molecular mode of action is incompletely understood. Many cellular events associated with lithium appear tied to mitochondrial function. Further, recent evidence suggests that lithium bioactivities are isotope specific. Here we focus on lithium effects related to mitochondrial calcium handling. Lithium protected against calcium-induced permeability transition and decreased the calcium capacity of liver mitochondria at a clinically relevant concentration. In contrast, brain mitochondrial calcium capacity was increased by lithium. Surprisingly, 7Li acted more potently than 6Li on calcium capacity, yet 6Li was more effective at delaying permeability transition. The size distribution of amorphous calcium phosphate colloids formed in vitro was differentially affected by lithium isotopes, providing a mechanistic basis for the observed isotope specific effects on mitochondrial calcium handling. This work highlights a need to better understand how mitochondrial calcium stores are structurally regulated and provides key considerations for future formulations of lithium-based therapeutics.

Slab dehydration and potassium-lithium recycling in the forearc indicated by potassium and lithium isotope compositions of exhumed metabasites

Slab dehydration at subduction zones has broad implications for arc magmatism, mantle heterogeneity and elemental cycling. We present the petrography, mineral chemistry and whole-rock potassium (K) and lithium (Li) isotopic compositions of subducted metabasites exhumed from serpentinite mud volcanoes from the Mariana forearc that were recovered during International Ocean Discovery Program Expedition 366, to evaluate the capability of K and Li isotopes for tracking slab dehydration and the evolution of the slab-derived fluids at shallow subduction zones. The results show that the δ41K values of HIMU-type alkali metabasites recovered from the shallow-sourced site (i.e., Fantangisña, −0.34 ± 0.06‰, 2SD, n = 3) are slightly higher than those from the deep-sourced site (i.e., Asùt Tesoru, −0.42 ± 0.20‰, 2SD, n = 8). In addition, all the HIMU-type metabasites have homogeneous radiogenic isotope compositions (e.g., Sr, Nd and Hf), and the clinopyroxenes therein show similar trace elements patterns, indicating they have a common mantle source. These observations together with the positive correlation between δ41K and δ11B suggest that K isotope fractionation most likely resulted from metamorphic dehydration. In contrast, no such correlation was observed for Li isotopes (δ7Li ranging from +3.7‰ to +6.6‰). The Li isotope compositions can be modeled by low-temperature fluid/rock interactions with varying water/rock ratios, implying that the Li isotopic system was mainly controlled by fluid metasomatism within the subduction channel. Notably, EM-II-type metabasites have the lightest K isotope compositions (−0.72‰ to −0.67‰) and heaviest Li isotope compositions (+8.1‰ to +8.3‰) in this study. These anomalous signatures were accompanied with the lowest Nb/Th, εNd(t) and εHf(t), indicating that the K and Li isotope data of EM-II-type metabasites were indicative of their mantle source (e.g., EM-II mantle reservoir). Rayleigh fractionation modeling illustrates that the deeply subducted metabasites are characterized by high K and Li concentrations, and low δ41K, but MORB-like δ7Li. Thus, they may transfer large amounts of fluid-mobile elements into the deep mantle that contributes to the K isotopic heterogeneity in the mantle.

Lithium Self-Diffusion in a Polymer Electrolyte for Solid-State Batteries: ToF-SIMS/ssNMR Correlative Characterization and Modeling Based on Lithium Isotopic Labeling.

Manufacturers aim to commercialize efficient and safe batteries by finding new strategies. Solid-state electrolytes can be seen as an opportunity to develop batteries with a high energy density. They allow the use of lithium foil as the anode, increasing the energy density. Also, they are composed of nonflammable materials making them safer than liquid electrolytes. However, to enhance the electrochemical performances of forthcoming solid-state lithium metal batteries, phenomena governing ionic conductivity have yet to be mastered in such devices. Lithium isotopic tracing was successfully used in previous works to further understand lithium ion transport mechanisms in batteries. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and 6/7Li high-resolution solid-state nuclear magnetic resonance (ssNMR) spectroscopy are two complementary techniques probing local and global scale, respectively. Both techniques can distinguish lithium isotopes. Here, four polymer membranes were elaborated with the same lithium concentration, but with various isotopic enrichments from 7.6 to 95.4% of 6Li. The selected material was a poly(ethylene oxide) (PEO) membrane containing lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) as lithium salt. They are widely studied in the lithium battery field. First, reliable ToF-SIMS and ssNMR methodologies were validated in light of the converging results. They led to accurate determination of lithium isotopic abundance of polymer membranes with a 1 or a 2% uncertainty, respectively. Then, the developed methodologies were applied to characterize lithium self-diffusion in a polymer membrane. Furthermore, numerical simulations based on a two-dimensional diffusion model compared with ToF-SIMS analyses allowed us to extract a lithium self-diffusion coefficient of 1.6 × 10-12 m2·s-1 at 60 °C, which complements other published values. The robust methodologies described in this work can be extended to various applications and materials. They stand as powerful strategies to better understand lithium ionic transport, especially in multiphase materials, for example, in hybrid solid-state electrolytes.

The reaction rate of radiative n8Li capture in the range from 0.01 to 10 T9

Within the modified potential cluster model (MPCM) with forbidden states, the total cross sections are calculated for capture in the ground and first excited states of the9Li nucleus in then8Li channel in the energy range from 10−5 eV to 5 MeV based onЕ1 andM1 transitions. The experimentally proved resonance atEc.m.= 0.232 MeV in the4P5/2wave andab initio-predicted4P3/2resonance at 1.32 MeV [Phys. Rev. C 103, 035801 (2021)] are considered. The strong impact of the asymptotic constant and channel spectroscopic factors on the total capture cross sections are responsible for the variation in the absolute values within factor two. As a consequence, the thermal cross sections areσtherm=24–46.8 mb. The evaluation ofσthermbased on the extrapolation ofab initiocross sections yields ∼85 mb. The reaction rate is calculated in the temperature range from 0.01 to 10T9. The reported reaction rates are compared at the benchmark point 1T9. The comparison of two datasets [Phys. Rev. C 103, 035801 (2021) and Phys. Rev. C 105, 064608 (2022)] on reaction rates recently calculated in microscopic models in extended temperature intervals shows the essential quantitative and qualitative differences. The comparative joint analysis of the reaction rates of radiative neutron capture on the lithium isotopes6,7,8Li is suggested for the choice of an optimal interval for the asymptotic constants.

Lithium isotope composition of Ediacaran dolostones from the Nuccaleena and Doushantuo formations

The end of the Cryogenian glaciations undoubtedly affected the chemistry of the Neoproterozoic oceans, with potential consequences for the evolution of life; the duration and extent of this influence are poorly constrained. Lithium (Li) isotopes in carbonates can be used to investigate past weathering events and riverine input into the oceans. Here, we report the Li isotope (δ7Li) composition of the Ediacaran cap dolostones (Marinoan) from the Nuccaleena Formation, South Australia and the Doushantuo Formation, South China to investigate changes in weathering during the aftermath of the Marinoan glaciation. The origin of dolomite formation is still hotly debated, and the inability to precipitate dolomite at ambient temperatures (the ‘dolomite problem’) has not yet been resolved. The dominant hypothesis for the presence of marine dolomite is that it is of secondary origin, owing to diagenetic replacement of calcium carbonate, but a second hypothesis is that it forms as a result of primary marine deposition; both are plausible hypotheses. Using carbon isotopes (δ13C) and ratios of manganese and strontium (Mn/Sr), we suggest that diagenesis may not have significantly altered the δ7Li composition of the primary dolomite, but this cannot be discounted without further diagenetic modelling. As a result, we cannot infer the δ7Li composition of the Ediacaran oceans, as further work must be done to address the impact of diagenesis on the δ7Li values. Nevertheless, this dataset contributes to a Li isotope chemostratigraphic record of the Proterozoic, which is a key element to understanding the emergence of complex life.

The influence of river-derived particles on estuarine and marine elemental cycles: Evidence from lithium isotopes

To examine the alteration of river-derived sediments through a large estuary and the implications for elemental cycling and global climate, this study analyses lithium (Li) isotopes and elemental concentrations (e.g., Li, Na, Mg, K, Ca, Fe and Al) of both the dissolved load and different phases of the sediment load (i.e., exchangeable, carbonate, oxide, clay and residue) in the Amazon estuary. The results show that river-derived sediments remove Li from the dissolved load, largely due to cation retention in secondary clays. By modelling the Li mass-balance and isotope fractionation, we estimate that the river-derived sediments gain 3–4 μg/g Li from the dissolved load in the Amazon estuary, with a Li isotope fractionation factor (αclay-solution) of approximately 0.975. Considering the whole Amazon estuary, the river-derived sediments remove around 3.6–4.8 × 109 g/yr of Li from the dissolved load. Specifically, around 1.0–1.7 × 108 g/yr of Li is removed from river water (∼1.8–3.0% of the dissolved Li discharge flux of the Amazon River) and around 3.5–4.7 × 109 g/yr of Li is removed from seawater, which represents a significant sink from the ocean. This estuarine Li sink is likely to be related to continental erosion rates; thus, continental weathering and erosion regimes could influence not only riverine Li input, but could also directly affect the Li sink, leading to a dual control on the Li budget and isotope composition in the ocean.