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Photo modulated optical reflectance (PMOR) is an ideal ultra-shallow junction area metrology technique for measurement of transistor dopant distribution in integrated circuit fabrication, and the characterization of process parameters such as implant energy, implant angle, and implant dose has a significant impact on the accuracy of the ion implantation process. This study utilized deep learning to analyze various process parameters concurrently and assessed its performance on boron-doped silicon samples, the data were obtained from the power curves measured from Carrier Illumination (CI) experiments in PMOR, a deep learning model with multi-task learning architecture was developed and trained to characterize multiple process parameters, and the PMOR model incorporating a multi-task learning architecture for process parameters demonstrated superior performance in terms of accuracy and speed of characterization. The analyses indicated that applying deep learning methods to CI metrology in PMOR technology is feasible. In particular, compared with the conventional carrier irradiation technique, the ability to obtain the implantation dose and doping profile along with other process parameters such as implantation energy, implantation angle, and implantation type can better assist in the accurate realization of the ion implantation process with acceptable accuracy and time cost. [ABSTRACT FROM AUTHOR]

The epitaxial growth of boron rich hexagonal zirconium diborides (h-ZrB2+δ) thin films on Si(111) substrates using the magnetron co-sputtering technique with elemental zirconium and boron is reported. The effect of process temperature (700–900 °C) on the compositions and epitaxy quality was investigated. The chemical composition of the films was found to have a higher boron to zirconium ratio than the ideal stoichiometric AlB2-type ZrB2 and was observed to be sensitive to process temperature. Films deposited at 700 °C exhibited intense diffraction peaks along the growth direction corresponding to (000ℓ) of h-ZrB2 using both lab and synchrotron-based x-ray diffractograms. The thermal and compositional stability of the epitaxial h-ZrB2+δ film was further evaluated under a nitrogen-rich environment through isothermal annealing which showed a reduction in in-plane misorientation during thermal annealing. The relative stability of deviating compositions and the energetics of impurity incorporations were analyzed using density functional theory simulations, and the formation of native point defects or impurity incorporation in h-ZrB2 was found to be endothermic processes. Our experimental results showed that an epitaxial thin film of h-ZrB2+δ can be grown on Si(111) substrate using a magnetron co-sputtering technique at a relatively low processing temperature (700 °C) and has the potential to be used as a template for III-nitride growth on Si substrates. [ABSTRACT FROM AUTHOR]

Background Purpose Methods Results Conclusions Boron neutron capture therapy (BNCT) is a targeted radiotherapy that relies on the 10B (n, α) 7Li reaction, which produces secondary particles with high linear energy transfer (LET), leading to a high relative biological effectiveness (RBE) in tumors. The biological effectiveness of BNCT is influenced by factors such as boron distribution and concentration, necessitating improved methods for assessing its radiobiological effects and clarifying the sensitivity of the differences in different factors to the biological effects.This paper introduces a method to evaluate the biological effects of BNCT using the cellular repair model. This method aims to overcome some of the limitations of current evaluation approaches. The primary goal is to provide guidance for clinical treatments and the development of boron drugs, as well as to investigate the impact of the synergistic effects of mixed radiation fields in BNCT on treatment outcomes.The approach involves three key steps: first, extending the radial energy deposition distribution of BNCT secondary particles using Geant4‐DNA. This allows for the calculation of initial DNA double‐strand breaks (DSBs) distributions for a given absorbed dose. Next, the obtained initial DSB distributions are used for DNA damage repair simulations to generate cell survival curves, then thereby quantifying RBE and compound biological effectiveness (CBE). The study also explores the synergistic effects of the mixed radiation fields in BNCT on assessing biological effects were also explored in depth.The results showed that the RBE of boronophenylalanine (BPA) and sodium borocaptate (BSH) drugs at cell survival fraction 0.01 was 2.50 and 2.15, respectively. The CBE of the boron dose component was 3.60 and 0.73, respectively, and the RBE of the proton component was 3.21, demonstrating that BPA has a significantly higher biological impact than BSH due to superior cellular permeability. The proton dose significance in BNCT treatment is also underscored, necessitating consideration in both experimental and clinical contexts. The study demonstrates that synergistic effects between disparate radiation fields lead to increased misrepairs and enhanced biological impact. Additionally, the biological effect diminishes with rising boron concentration, emphasizing the need to account for intercellular DNA damage heterogeneity.This methodology offers valuable insights for the development of new boron compounds and precise assessment of bio‐weighted doses in clinical settings and can be adapted to other therapeutic modalities. [ABSTRACT FROM AUTHOR]

Recent developments in spatially-resolved boron isotopic analysis using laser ablation as ameans of sample introduction to MC-ICPMS instruments (LA-MC-ICPMS) increasingly allow researchers to explore the spatial heterogeneity of the boron isotopic composition of a range of geochemical applications, for example in palaeoclimatology and mantle petrology. However, previous work has shown that a diffuse interference centred near 10B, when measuring samples with a calcium-rich matrix, can significantly bias especially the measurement on 10B, affecting the accuracy of boron isotope measurements. Although several correction approaches have yielded sufficiently accurate analyses of d11B in calcium carbonate, the root cause of this interference is still not fully resolved. Here, we explore the various potential sources of inaccuracy in boron isotope measurements made using (LA-)MC-ICPMS by experimenting with dry and wet plasma conditions, in both solution and laser ablation mode (in the former case, our solution (Ca-Mg)/B ratios broadly mimic those found in natural samples). In solution mode, we find that irrespective of wet or dry plasma conditions, the introduction of a Ca-containing matrix yields a baseline up to ~4 and ~14 times higher around m/z z 10 for wet and dry plasma conditions, respectively, compared to both a Mg-only matrix and lack of matrix. In order to explore this further, we performed mass scans around m/z z 10 during laser ablation of different carbonates with varying matrix [Ca]. These show that the m/z z 10 interference scales linearly with a mixture of the calcium content of the analyte matrix and 40Ar4+ ion beam intensity, as previously hypothesised. Moreover, by experimenting with different plasma loading scenarios during the ablation of CaCO3, i.e. varying laser spot sizes, we find that permil-level inaccuracies in d11B may occur when the analyte ablated mass is significantly different than that of the standard used to calibrate instrumental mass bias. This is important given that we also show that different commonly-used reference materials ablate at very different rates, which illustrates the need for a careful standardisation approach irrespective of broader matrix effects when sub-permil level accuracy and precision are desirable when utilising LA-MC-ICPMS. [ABSTRACT FROM AUTHOR]

The availability of lithium resources is of great significance for the development of modern technologies, as well as for civil and military industries. The Qinghai-Tibet Plateau is a region known for its abundance of lithium-rich salt lakes. However, the specific origin of lithium in these lakes is still unknown, which hinders the advancement of the lithium resource business in this region. To research this issue, this study involved the collection of 20 samples from Lakkor Co Salt Lake on Qinghai-Tibet Plateau, encompassing samples of surface brine, cold springs, fresh lakes, and recharge rivers. The composition of anions and cations in these samples was determined. Furthermore, the analysis extensively utilized the Piper three-line diagram, Gibbs model, and ion proportion coefficient. The findings of this study indicate that as the moves from the recharge water system to salt lake, there is a transition in water type from strong carbonate to moderate carbonate and weak carbonate, as well as Na sulfate. This research based on a similar source of both lithium and boron, utilized ion correlation analysis and boron isotope study in the Lakkor Co area, and analyzed the source and transporting process of lithium. The main origin of lithium in Lakkor Co is the dissolution of lithium-rich rocks, recharge water systems, and deep hydrothermal fluids. These findings are highly significant in enhancing the foundational data of lithium-rich brine resources in the Qinghai-Tibet Plateau and are beneficial for assessing the future development of such deposits. [ABSTRACT FROM AUTHOR]

Serpentinite dehydration in subduction zones plays a pivotal role in geochemical cycling on Earth. A number of geochemical studies on arc magmas have elucidated the contributions of serpentinite-derived fluids to mantle sources. However, due to complex geological overprints during subduction zone processes, discerning serpentinite signatures in exposed metamorphic rocks within fossil subduction zones remains challenging. In this study we address these difficulties through in-situ investigations of tourmaline, the geochemistry of which reflects the host environment as well as potential fluid-induced processes. The presence of zonations in tourmaline makes it an excellent recorder of consecutive geological events. Integrated major and trace elements along with in-situ boron isotopes of tourmaline from the high-pressure Sopron area (Hungary) in the Eastern Alps were used to unravel fluid action sourced from serpentinite. Despite the presence of color zoning, tourmaline in the orthogneiss (Tur-G) has low X Mg [Mg/(Mg + Fe)] of ca. 0.3–0.6 and δ11B values of around −11 ‰, along with variable trace element compositions. Petrological observations and geochemical analyses suggest that the inner domains of Tur-G are of igneous origin, while the outer rims are likely affected by subsequent metamorphic events. Tourmaline in metasomatized kyanite-quartzite (Tur-K) veins exhibits distinct geochemical zoning, and preserves metamorphic cores and fluid-induced rims. The inner domains of Tur-K display low X Mg (<0.6), relatively high trace element concentrations and δ11B values of less than −10 ‰, whereas the overgrowths exhibit extremely high X Mg values (>0.99), low trace element concentrations and high δ11B values reaching up to +21 ‰, clearly indicating the incorporation of serpentinite-derived Mg-11B-rich fluids. Through comparison with other metamorphic and metasomatic tourmalines in (ultra)high-pressure rocks globally, we establish that tourmaline with high X Mg > 0.85 and δ11B values >0 ‰ may serve as an effective proxy for detecting serpentinite-derived fluids in subduction zones. [ABSTRACT FROM AUTHOR]

Boron geochemistry from biogenic carbonates offer valuable information about ocean pH and CO2 chemistry. However, application to geological carbonate deposits suffers from analytical difficulties in obtaining geochemical signals exclusively from the carbonate phase. Sequential leaching with reagents and acids has the potential to overcome such an issue. There is, however, little systematic investigation about the efficiency of sequential leaching in isolating carbonate‐associated boron from siliciclastic matrix. Here, we developed a sequential leaching protocol and applied it to methane‐derived‐authigenic‐carbonate samples. Using the leachate δ11B signatures, elemental composition, and mineral composition of residues, we show that the sequential leaching is able to improve the separation of boron from different phases. Buffered hydrogen peroxide removes organic matter and also some silicate phases resulting low δ11B values. Leaching with NH4Ac removes adsorbed boron though may also partially leach some carbonate phases. The first few leaching steps with diluted acetic acid dissolve carbonate phases. Depending on the sample type, these may also capture some remaining adsorbed boron from the preceding NH4Ac leaching. Once the adsorbed boron is completely removed, as indicated by the progressively higher δ11B values during the following acid leaching steps, representative carbonate composition can be derived. The accuracy of this protocol is demonstrated with leaching experiments using artificial deep sea coral carbonate and clay mixtures that give the representative carbonate‐associated δ11B within error of the pure coral value. Our results provide insights into characteristic signatures derived from silicates and organic matter that need to be considered in boron isotope analyses of impure marine carbonates. Key Points: Boron signals from geological carbonate deposits are difficult to isolate from siliciclastic components of mixed matrix samplesA calibrated sequential leaching protocol was developed to extract boron from the carbonate phase of mixed carbonate‐silicate limestonesSuccessful separation is possible in samples with only 25% carbonate, provided the protocol is adjusted for carbonate content [ABSTRACT FROM AUTHOR]

Context. The evolution and fate of massive stars are thought to be affected by rotationally induced internal mixing. The surface boron abundance is a sensitive tracer of this in early B-type main sequence stars. Aims. We test current stellar evolution models of massive main sequence stars which include rotational mixing through a systematic study of their predicted surface boron depletion. Methods. We construct a dense grid of rotating single star models using MESA, for which we employ a new nuclear network which follows all the stable isotopes up to silicon, including lithium, beryllium, boron, as well as the radioactive isotope aluminium-26. We also compile the measured physical parameters of the 90 Galactic early B-type stars with boron abundance information. We then compare each observed stars with our models through a Bayesian analysis, which yields the mixing efficiency parameter with which the star is reproduced the best, and the probability that it is represented by the stellar models. Results. We find that about two-thirds of the sample stars are well represented by the stellar models, with the best agreement achieved for a rotational mixing efficiency of ∼50% compared to the widely adopted value. The remaining one third of the stars, of which many are strongly boron depleted slow rotators, are largely incompatible with our models, for any rotational mixing efficiency. We investigate the observational incidence of binary companions and surface magnetic fields, and discuss their evolutionary implications. Conclusions. Our results confirm the concept of rotational mixing in radiative stellar envelopes. On the other hand, we find that a different boron depletion mechanism, and likely a different formation path, is required to explain about one-third of the sample stars. The large spread in the surface boron abundances of these stars may hold a clue to understanding their origin. [ABSTRACT FROM AUTHOR]

The quality control (QC) of an analytical method for any analytical data measurement depends directly on the matrix matching standard and certified reference material (CRM). In many cases, obtaining a matrix match standard and an RM or CRM as a control sample in sufficient amounts for QC analysis is difficult. It is also not advised to use a CRM as a standard for routine analysis owing to its high cost and availability in lower quantities. In view of this, in-house reference standards/materials for isotopic compositions of boron (IC, 10B/11B atom ratio) in natural and enriched boron carbide matrix were prepared in the present work. These in-house reference standards/materials will be helpful for method validation, quality control and quality assurance in the IC determination of boron carbide samples using particle induced gamma-ray emission (PIGE) method. A total of five different isotopic compositions, namely natural (19.8 atom% of 10B) and 30, 40, 50 and 67 atom% of 10B-enriched B4C, were prepared in sufficient quantities (0.8 kg each). Homogeneity and stability tests were performed for the prepared materials with respect to their isotopic composition by analysing direct powder samples using the external PIGE method, and they were found sufficiently homogeneous and stable for the property value for use as in-house reference standards. Assigned values of isotopic compositions were determined through external PIGE using both powder and pellet samples. The obtained values of the isotopic compositions are 0.247(1), 0.427(2), 0.662(3), 0.991(4), and 2.028(7) for the natural and 30, 40, 50 and 67 atom% of 10B-enriched boron carbide, respectively. [ABSTRACT FROM AUTHOR]

The effects of atomic mass in terms of its zero-point vibrational energy, on molar volume, glass transition temperature Tg, and viscosity are studied in glassy and supercooled B2O3 liquids using boron isotope substitutions. The molar volume decreases and Tg and isothermal viscosity increase on the substitution of lighter 10B isotopes with the heavier 11B isotopes. These effects are argued to be a manifestation of the higher zero-point vibrational energy of the lighter isotope, which along with the anharmonicity of the potential well, results in a longer equilibrium inter-atomic distance and larger mean-square displacement with respect to that for the heavier isotope. The isotope effect on viscosity is increasingly enhanced as the temperature approaches Tg, which is shown to be consistent with the prediction of the elastic models of viscous flow and shear relaxation. [ABSTRACT FROM AUTHOR]

Coral skeletal B/Ca (effectively B/CO 3 2–), in combination with boron isotopic composition (δ11B), has been used to reconstruct the dissolved inorganic carbon chemistry of coral calcification media and to explore the biomineralisation process and its response to ocean acidification. This approach assumes that B(OH) 4 −, the B species incorporated into aragonite, competes with dissolved inorganic carbon species for inclusion in the mineral lattice. In this study we precipitated aragonite from seawater in vitro under conditions that simulate the compositions of the calcification media used to build tropical coral skeletons. To deconvolve the effects of pH and [CO 3 2–] on boron incorporation we conducted multiple experiments at constant [CO 3 2–] but variable pH and at constant pH but variable [CO 3 2–], both in the absence and presence of common coral skeletal amino acids. Large changes in solution [CO 3 2–], from < 400 to >1000 µmol kg−1, or in precipitation rate, have no significant effect on aragonite B/Ca at pH total of 8.20 and 8.41. A significant inverse relationship is observed between solution [CO 3 2–] and aragonite B/Ca at pH total = 8.59. Aragonite B/Ca is positively correlated with seawater pH across precipitations conducted at multiple pH but this relationship is driven by the effect of pH on the abundance of B(OH) 4 – in seawater. Glutamic acid and glycine enhance the incorporation of B in aragonite but aspartic acid has no measurable effect. Normalising aragonite B/Ca to solution [B(OH) 4 –] creates K D B(OH)4− which do not vary significantly between pH treatments. This implies that B(OH) 4 – and CO 3 2– do not compete with each other for inclusion in the aragonite lattice at pH total 8.20 and 8.41. Only at high pH (8.59), when [B(OH) 4 –] is high, do we observe evidence to suggest that the 2 anions compete to be incorporated into the lattice. These high pH conditions represent the uppermost limits reliably measured in the calcification media of tropical corals cultured under present day conditions, suggesting that skeletal B/Ca may not reflect the calcification media dissolved inorganic carbon chemistry in all modern day corals. [ABSTRACT FROM AUTHOR]

Wildfires are hazards of increasing significance in recent decades. Our ability to forecast the evolution of fire regimes is inhibited by the lack of records of key fire parameters such as fire severity. Boron isotopes in the soil clay fraction have been shown to vary with fire severity, where increased δ 11B coincides with higher fire severity. To elucidate the relationship between the B isotope composition of soil clays and fire events, we performed adsorption experiments by reacting rainwater with combusted leaves to analyse how B isotopes are fractionated during processes leading to the imparting of boron from plants to clay minerals in soil during and following combustion. We find that < 5% of B is volatilised during combustion of leaves and barks, where 11B is preferentially volatilised. No isotopic fractionation was detected during the leaching of leaves ash with rainwater, possibly due to the large water:clay ratio in our experiments. Adsorption of B from leaching solutions onto clay minerals shows isotopic fractionation, and hysteresis of the adsorbed B fraction. For experiments at pH between 7 and 9, the isotope fractionation between adsorbed and dissolved B (Δ 11B adsorbed-dissolved) ranges from −8.8 to −14.5 ‰ , indicating preferential adsorption of 10B onto clays compared to 11B. For experiments at pH > 10, the Δ 11B adsorbed-dissolved values range from +11.2 to +19.4 ‰ , indicating a preferential adsorption of 11B over 10B. Irregardless of pH, clay fractions in all experiments show increases in δ 11B, as the leaching solutions have high δ 11B relative to the soil clay minerals prior to their interaction. Ash of leaves combusted at 550 °C (highest temperature in our experiments) induce the greatest increase in solution pH and δ 11B in clays. Our experiments suggests that the higher B isotope composition of clays following a high severity fire is likely imparted by solutions that leach isotopically heavy B from the combusted canopy. [ABSTRACT FROM AUTHOR]

We have established a method for the simultaneous measurement of element abundances and boron isotopic compositions of bulk‐rock silicate samples by laser ablation coupled to two different ICP‐MS instruments. Fifteen silicate reference materials were prepared as micro‐particulate pressed powder pellets (MP) for analysis. Approximately 1/5th of the ablated material was transported to a single‐collector ICP‐MS for elemental measurement, while 4/5ths were sent to a multi‐collector ICP‐MS for boron isotope ratio measurement. Compositions of different milling materials (agate, zirconium oxide, tungsten carbide, sintered corundum and silicon nitride) were measured for the evaluation of potential contamination during sample preparation. Determined element mass fractions are in agreement with literature values within ±20%. For boron isotope ratios, the matrix‐dependent background elevation across the m/z from 9.9 to 11, and the effect of ablation mass was quantified. Measured δ11B values of most reference materials are consistent with literature values within ±1‰. The intermediate measurement precision is ±0.3‰ for JB‐2 with 30 μg g−1 B and ±0.4‰ for JA‐2 with 21 μg g−1 B. A publically available, web‐based streamlit app was developed for data processing (https://zenodo.org/doi/10.5281/zenodo.11150471). This paves the way for combined, accurate and precise elemental and boron isotope ratio measurements of geological materials. [ABSTRACT FROM AUTHOR]

The boron isotope palaeo-pH/CO 2 proxy is one of the key quantitative tools available to reconstruct past changes in the concentration of CO 2 in the atmosphere. In particular, marine calcifying organisms have been shown to be useful archives of this proxy, enabling quantitative variations in pH/CO 2 to be reconstructed throughout the Cenozoic. In order to provide an alternative proxy archive to the widely used planktonic foraminifera, we investigated the symbiont-bearing, high-Mg, shallow-dwelling, tropical large benthic foraminifera (LBF) species Operculina ammonoides and present a calibration of the relationship between the shell boron isotopic composition and seawater pH. We investigated specimens collected from both several reefs as well as grown in laboratory culture experiments in which pH and DIC were decoupled from each other, measuring newly-formed chambers using laser-ablation as a sample introduction technique. Based on our laboratory culture samples, the resulting linear relationship between the in situ boron isotopic composition of aqueous borate ion (B(OH) 4 −) and the shells of O. ammonoides is characterised by a gradient of 0.38 - 0.10 + 0.12 . In contrast, the boron isotopic composition of the field collected samples displays a near 1:1 relationship with B(OH) 4 −. We suggest that the shallow slope of the laboratory culture regression is the result of the difference between their micro-environment carbonate chemistry and that of the surrounding seawater driven by a pH dependence of the relative rates of calcification and photosynthesis. Based on a model of the effect of these processes on the diffusive boundary layer, we show that this effect is expected in laboratory culture experiments free from micro-turbulence, but not in the foraminifer's natural environment. As such, we demonstrate the utility of these organisms as proxy archive, while also highlighting how laboratory experimental design has the potential to drive important changes in the micro-environment and resulting shell chemistry of organisms of this size. Given that the genus Operculina originated in the late Palaeocene, this work paves the way towards deep-time palaeo-pH/CO 2 reconstructions using foraminifer species which have a very closely related modern representative. [ABSTRACT FROM AUTHOR]

The magmatic-hydrothermal transition in granite-related, rare-metal metallogenic systems has received great attention as economic rare metal (including rare earth) minerals reach saturation and trigger mineralization at this stage. However, deciphering the details of the melt-fluid evolution process and the distribution behavior of rare metals remains difficult. Here, we applied tourmaline chemistry and B isotopes to unravel processes at the magmatic-hydrothermal transition that are responsible for rare-metal partitioning in the Huoshibulake (HS) and Tamu (TM) REE-Nb-mineralized intrusions in Southern Tianshan, SW Central Asian Orogenic Belt. Three types of tourmaline are identified in the plutons: (1) disseminated tourmaline in the granite, with a brown-yellow core (HS-DB) and blue-green rim (HS-DG); (2) orbicular tourmaline, with a brown-yellow core (HS-OB and TM-OB) and blue-green rim (HS-OG and TM-OG); and (3) vein tourmaline (HS-V and TM-V). Compositionally, all these tourmalines exhibit extremely low Ca and Mg contents and are classified as schorl. The substitution processes of major-element variations are dominantly caused by (Al,□)(Fe,Na)−1 exchange vectors. Four generations of tourmaline crystallization are established based on the petrographic, compositional, and B isotopes evolution of the tourmaline. First, the HS-DB crystals crystallized from the highly evolved residual melt, and then HS-OB and TM-OB precipitated from immiscible B-rich aqueous melts during the magmatic-hydrothermal transition. Subsequently, the blue-green overgrowths (HS-DG, HS-OG, and TM-OG) crystallized from exsolved hydrothermal fluids. Finally, the formation of HS-V and TM-V resulted from another melt pulse from a deeper magma chamber. The magmatic tourmaline exhibits a narrow range of δ11B values between −12.6 to −10.0‰, while the hydrothermal tourmaline shows significantly heavier and variable δ11B values ranging from −10.2 to −4.9‰. The fractionation of B isotopes is reproduced by Rayleigh fractionation modeling. Lower Nb and Sn contents in the orbicular tourmaline relative to those precipitated from the residual melt, along with the lack of rare-metal minerals in the orbicules, indicate that B-rich melt/fluid exsolution does not necessarily contribute to the rare-metal mineralization. In comparison, the veins contain abundant rare-metal and REE minerals in close paragenesis with fluorite, and the vein tourmaline shows high-Nb and -Sn contents. These observations suggest that saturation of fluorite triggered the precipitation of rare metals, and fluorine played a critical role in rare metal concentration and mineralization. This study highlights the potential of tourmaline to trace the magmatic-hydrothermal transition and provide insights into rare-metal mineralization in the granitic systems. [ABSTRACT FROM AUTHOR]

We present coupled textural, elemental, and boron isotopic data of tourmaline from the large Zhunuo–Beimulang collision-related porphyry copper deposits (PCDs) located within the western Gangdese, Tibet. Based on morphology and high-resolution mapping, the tourmaline is classified into three paragenetic generations. The first generation of schorlitic Tur-1 occurs in the monzogranite porphyry as disseminations intergrown with porphyritic K-feldspar and plagioclase. It shows decreasing Fe and Ca and increasing Mg and Al contents from core to rim and has relatively homogeneous δ11B values (− 9.9 to − 8.6‰); low Fe3+/(Fe2+ + Fe3+), Cu, F, H2O, and Sr/Y ratios; and high rare earth elements. These features indicate Tur-1 formed in a low fO2 and metal-poor granitic magma during the pre-mineralization stage. The second generation of porphyritic euhedral Tur-2 is hosted in diorite porphyry enclaves and dikes, where it is intergrown with plagioclase and biotite. It forms part of the schorl-dravite solid solution, with high Fe3+/(Fe2+ + Fe3+), Cu, F, H2O, Sr/Y, and δ11B (− 9.7 to − 5.1‰) values. These features indicate it crystallized from a hydrous, oxidized, metal-, and volatile-rich diorite magma. The third generation of Tur-3 is the most volumetrically important and occurs as veinlets and disseminations in the porphyry, or around Tur-1 and Tur-2. It shows radial and oscillatory zoning and is locally intergrown with chalcopyrite and pyrite within the main mineralization assemblage. It has δ11B values (− 10.5 to − 6.0‰) that overlap with Tur-1 and Tur-2 values. Tur-3 also has variable Fe3+/(Fe2+ + Fe3+), Cu, and volatiles (F and H2O), indicating it crystallized from oxidized to relatively reducing metal- and volatile-rich hydrothermal fluids. Overall, the three generations of tourmaline show a narrow range of δ11B values between − 10.5 and − 5.1‰ that are indicative of a single magmatic source. The high Cu, ferric iron, volatiles, and δ11B values in Tur-2 are interpreted to reflect injection of diorite magma into an open crustal magma storage system that led to the formation of an oxidizing and metal-volatile-rich porphyry system. The three stages of tourmaline formation reflect evolution of the magmatic–hydrothermal system from low fO2 conditions towards more oxidizing, volatile-rich conditions and then a return to more reducing conditions that accompanied Cu precipitation. Overall, the injection of oxidized metal-rich magma into a long-lived magma reservoir is a critical driving force for the development of collision-related PCDs. [ABSTRACT FROM AUTHOR]

Boron isotopic ratio measurement is very important in the nuclear industry because it is used as neutron poison (in the form of boric acid or a B4C pellet) and control rod material (B4C pellet) in nuclear power plants. Since 10B has a higher neutron absorption cross-section, enriched 10B is used in the nuclear industry and the extent of enrichment varies from 50–90 %. Therefore, it is essential to determine the 10B/11B ratio in boric acid and B4C. The prime purpose of the present study is to utilize LA-ICPMS for evaluating 10B/11B ratio both in solution (boric acid) and solid (B4C pellet) without any pre-treatment so that the difficulty in dissolution or powdering process of B4C (one of the hardest materials) can be avoided and the B4C pellet can be reused. The results obtained from LA-ICPMS for the B4C pellet are discussed and compared with the solution ICPMS, TIMS, and LIMS. The solutions of boric acid (natural abundance) and dissolved B4C (natural & ∼67 % enriched isotopic composition) were analyzed by LA-ICPMS and validated by liquid sampling ICPMS data. [ABSTRACT FROM AUTHOR]

This study explores the capability of amphibole in tracing the physicochemical process of magma mixing through spatially associated gabbros, mafic microgranular enclaves (MMEs) and granodiorites from central Tibet. These rocks share similar zircon ages as well as zircon Hf‐O and plagioclase Sr isotopes. However, the amphiboles within the gabbros and granodiorites have different Sr and B isotope compositions, while amphiboles with both heterogeneous isotopic imprints occur in the MMEs. According to data and modeling, significant mixing of two isotopically distinct magmas is recorded by amphibole but not by zircon and plagioclase. Based on a synthesis of petrography, geochemistry and thermobarometry, we interpret this inconsistency by the crystallization order of minerals and propose that magma mixing occurred after the parent magma was emplaced at ∼10 km and cooled to ∼750°C. Our study highlights that amphibole may be a more sensitive tracer of magma mixing relative to other commonly used methods. Plain Language Summary: Magma mixing significantly shapes the composition of silicic igneous rocks representing the major constituent of the upper continental crust. Since bulk‐rock composition may only bear the average of mixed sources, in situ techniques such as Hf‐O isotopes in zircon and Sr‐Pb isotopes in plagioclase are widely used to investigate the details of magma mixing. However, these methods cannot constrain how magma mixing operates in the deep crust. This study novelly uses in situ Sr‐B isotopes and trace elements in amphibole to trace the physicochemical process of magma mixing through spatially associated gabbros, mafic microgranular enclaves and granodiorites from the central Tibetan Plateau. Our data show that significant mixing of two isotopically distinct magmas is recorded by amphibole but not by zircon and plagioclase. We demonstrate that the amphibole geochemistry (i.e., trace element, Sr‐B isotope compositions) may be more sensitive in tracing magma mixing relative to traditional isotopic tools and has the potential to unravel the physicochemical process(es) of magma mixing in the deep crust. In addition, our work reinforces the use of B isotopes in amphibole to discern the nature (fluids released from altered oceanic crust vs. residual slab) of the slab components that metasomatized the supra‐subduction mantle. Key Points: The amphiboles in central Tibetan magmatic complex have contrasting geochemical and Sr‐B isotopic compositionsSignificant magma mixing is well recorded by amphibole but not by zircon and plagioclaseAmphibole is a more sensitive tracer of magma mixing relative to zircon and plagioclase [ABSTRACT FROM AUTHOR]

Borophene, a boron analogue of graphene, is typically metallic, while all bulk boron phases are insulating. Here, we predict by first‐principles calculations that recently synthesized bilayer borophene, being suggested to be composed of two stacked v1/12 sheets, is a semiconductor with a bandgap of 1.13 eV, almost the same as that of silicon. It is shown that the stacking mode between two boron sheets as well as the density and pattern of the interlayer boron‐boron (B─B) bonds are the key factors for opening the bandgap in the otherwise metallic boron sheet. Moreover, the bilayer borophene exhibits electron mobility of 878.6 cm2 V−1 s−1 and a significantly higher optical absorption coefficient in the visible region than silicon. These excellent electronic and optical properties hosted in a two atom‐thick space, together with high thermal and mechanical stability, position the bilayer borophene as a promising nanomaterial for maintaining the miniaturization of electronics. [ABSTRACT FROM AUTHOR]

The adsorption performance of titanium-based lithium ion sieves for Li+ through H+–Li+ exchange is greatly limited by the pH value of brine. To improve the adsorption capacity of HTO-P (formed titanium-based lithium ion sieves) for Li+, the adsorption characteristics and dynamic performance in Tibetan brine–NaHCO3 (NaHCO3 as a buffer added into the brine used) were studied. The addition of NaHCO3 reduces the aggregation of H+ and maintains the pH value at ∼7.5, which also accelerates the mass transfer rate of Li+ in the initial adsorption stage. Compared with Tibetan brine, the equilibrium adsorption capacity and recovery ratio of HTO-P for Li+ in Tibetan brine–NaHCO3 increase by 60% and 70%, respectively, and the adsorption equilibrium time is shortened by one-third. Moreover, the dynamic saturated adsorption capacity of HTO-P for Li+ reaches 14.25 mg g−1 in Tibetan brine–NaHCO3. This work provides a basis for the direct lithium adsorption and extraction process from salt lake brines. [ABSTRACT FROM AUTHOR]

Loss of slab-derived volatile and fluid-mobile elements (FME) through the forearc may represent a large, unaccounted for flux out of convergent margins. To address volatile recycling through the forearc and potential changes in fluid source from the progressively dehydrating subducting slab, we collected water samples from 44 different cold and thermal (>40 °C) springs on a transect across the outer forearc (∼20–40 km to the subducting slab), forearc (∼40–80 km to the slab), and arc (∼80–120 km to the slab) in Costa Rica. We focused on the heavy halogens (Cl, Br, I), as well as B and Li, given their high fluid mobility and thus limited potential for modification by subsequent fluid-rock interaction. Chlorine, boron, and lithium stable isotope ratios show dramatic ranges from −1.7 to +1.0 ‰ (n = 43), −12.0 to +30.9 ‰ (n = 35), and −2.4 to + 27.5 ‰ (n = 38), respectively, with distinct changes across the transect consistent with a sedimentary pore fluid component in the outer forearc, fluids sourced from dehydration of the slab (sediment and altered oceanic crust) in the forearc, and minimal slab input near the arc. Variations in elemental ratios (Br/Cl, I/Cl, B/Cl, Li/B) across the transect are also largely consistent with evolving FME sources during subduction. Boron isotope ratios in some higher-temperature fluids are modified due to phase separation, whereas, lithium and chlorine isotope ratios are minimally modified. Springs located in the outer forearc along a major fault (Falla Morote) deviate from the consistent across-arc trend and record almost the full range of observed isotopic values. This extreme range in values along the fault likely represents a combination of adsorption/desorption effects, weathering, and mixing with crustal fluids. Mass balance calculations show that up to ∼ 70 % of Cl, ∼50 % of Br, ∼30 % of B, ∼15 % of I, and minimal Li may be recycled through the outer forearc and forearc springs of the Costa Rican margin, therefore fluid emission via springs in global forearc regions are a potentially significant output for FME at convergent margins. [ABSTRACT FROM AUTHOR]

Potassium borate glass has great potential as an ion transport material. The ion transport rate is closely related to the microstructure of the glass. However, the disorder and variations in boron and oxygen atom types in the glass structure pose challenges in the analysis of this complex glass structure. In this work, the structure of potassium borate glass was unveiled through the neutron diffraction method and ab initio molecular dynamics (AIMD) simulations. The B–O, K–O, and O–O atomic interactions, bond lengths, coordination numbers, cavity distribution, ring structure distributions and other detailed information in the microstructure of potassium borate glass were obtained. By comparing the structure and properties of potassium borate glass with those of crystals of similar components, it is found that the bond lengths of 3B–BO (BO, bridging oxygen), 4B–BO and 3B–NBO (NBO, non-bridging oxygen) are longer than those of corresponding crystals, so the structure of the boron–oxygen network is looser and the density is smaller than that of similar crystals. Moreover, we found a rule that in both borate glass and crystal, the increase of NBO shortened the length of the B–O bond, and the increase of 4B increased the length of the B–O bond. The key structures affecting the transport rate of K+ were NBO, chain structure units and cavities. This work will provide reference data for designing and developing electrically conductive amorphous materials with faster potassium-ion transport rates. [ABSTRACT FROM AUTHOR]

The crystal chemistry of inderborite, a B-rich mineral (B2O3 ~41 wt%) with ideal formula CaMg[B3O3(OH)5]2·6H2O or CaMg[B3O3(OH)5]2(H2O)4(H2O)4·2H2O from the Inder Deposit, Kazakhstan, was re-investigated by a multi-methodological approach (single-crystal X-ray and neutron diffraction, electron probe micro-analysis in wavelength-dispersive mode, laser ablation multi-collector inductively mass spectrometry). The experimental findings show that the real chemical formula of inderborite from the Inder Deposit is virtually identical to the ideal one: the fraction of potential isomorphic substituents is insignificant. Boron is, therefore, the only industrially relevant element occurring in this mineral. The in situ B isotope composition of the Inder inderborite shows enrichment in the heavy 11B isotope, giving a weighted mean δ11BNIST951 of +35.15 ± 0.49 ‰ (2σ, N = 6). Such a positive δ11B value falls within the range of values in which the source of boron is ascribable to marine reservoirs rather than to terrestrial ones. X-ray (at 293 K) and neutron (at 20 K) structure refinements confirm that the principal building block unit of the structure is a [B3O3(OH)5]2– ring, consisting of two BO2(OH)2 tetrahedra (B-ion in sp3 electronic configuration) and one planar-triangular BO2OH group (B-ion in sp2 electronic configuration). In the [B3O3(OH)5]2– ring, all the oxygen atoms that are not shared between two boron atoms are protonated. The building units share corners with the CaO2(OH)4(OH2)2 polyhedra and Mg(OH)4(OH2)2 octahedra, forming hetero-polyhedral sheets parallel to (100). Subsequent hetero-polyhedral sheets are mutually connected only by H-bonding interactions, even mediated by the zeolitic ("interstitial") H2O molecules. Ten out of 11 independent oxygen sites in the structure of inderborite are involved in H-bonds as donors or acceptors, and this reflects the pervasive effect of the H-bonding network. The role played by the complex H-bond network is expected to be substantial on the stability of the crystalline edifice, having effects within the single hetero-polyhedral sheet, between subsequent sheets, and in the bonding with the interstitial zeolitic H2O molecules. Finally, the potential utilizations of inderborite, as a B-bearing mineral, are discussed. [ABSTRACT FROM AUTHOR]

The Newark Basin comprises Late Triassic and Early Jurassic fluvio-lacustrine rocks (Stockton, Lockatong, Passaic, Feltville, Towaco, and Boonton Formations) and Early Jurassic diabase intrusions and basalt lava flows. Boron concentrations in private well water samples range up to 18,000 μg/L, exceeding the U.S. Environmental Protection Agency Health Advisory of 2000 μg/L for children and 5000 μg/L for adults. Boron was analyzed in minerals, rocks, and water samples using FUS-ICPMS, LA-ICP-MS, and MC ICP-MS, respectively. Boron concentrations reach up to 121 ppm in sandstone of the Passaic Formation, 42 ppm in black shale of the Lockatong Formation, 31.2 ppm in sandstone of the Stockton Formation, and 36 ppm in diabase. The δ11B isotopic values of groundwater range from 16.7 to 32.7‰, which fall within those of the diabase intrusion (25 to 31‰). Geostatistical analysis using Principal Component Analysis (PCA) reveals that boron is associated with clay minerals in black shales and with Na-bearing minerals (possibly feldspar and evaporite minerals) in sandstones. The PCA also shows that boron is not associated with any major phases in diabase intrusion, and is likely remobilized from the surrounding rocks by the intrusion-related late hydrothermal fluids and subsequently incorporated into diabase. Calcite veins found within the Triassic rock formations exhibit relatively elevated concentrations ranging from 6.3 to 97.3 ppm and may contain micro-inclusions rich in boron. Based on the available data, it is suggested that the primary sources of boron contaminating groundwater in the area are clay minerals in black shales, Na-bearing minerals in sandstone, diabase intrusion-related hydrothermal fluids, and a contribution from calcite veins. [ABSTRACT FROM AUTHOR]

Boron-doped polycyclic aromatic hydrocarbons exhibit excellent optical properties, and regulating their photophysical processes is a powerful strategy to understand the luminescence mechanism and develop new materials and applications. Herein, an electrochemically responsive B–O dynamic coordination bond is proposed, and used to regulate the photophysical processes of boron-nitrogen-doped polyaromatic hydrocarbons. The formation of the B–O coordination bond under a suitable voltage is confirmed by experiments and theoretical calculations, and B–O coordination bond can be broken back to the initial state under opposite voltage. The whole process is accompanied by reversible changes in photophysical properties. Further, electrofluorochromic devices are successfully prepared based on the above electrochemically responsive coordination bond. The success and harvest of this exploration are beneficial to understand the luminescence mechanism of boron-nitrogen-doped polyaromatic hydrocarbons, and provide ideas for design of dynamic covalent bonds and broaden material types and applications. Boron-doped polycyclic aromatic hydrocarbons with dynamic covalent bonds have interesting optical properties, but electricity-responsive bonds are less studied. Here, the authors report an electrochemically responsive B-O coordination bond with short switching time. [ABSTRACT FROM AUTHOR]

The paper presents calculations of the process parameters of the chemical isotope exchange with a thermal flow reversal in the BF3–C6H5OCH3 system and engineering data for rectifying columns for its implementation. It is shown that the calculated parameters are in good agreement with those found the literature. The best engineering data are obtained for rectifying columns intended for the production of enriched (96 wt.% 10B enrichment) boron in the amount of 2 and 4 tons per year. [ABSTRACT FROM AUTHOR]

Synchrotron x-ray diffraction (SR-XRD) and X-ray absorption fine structure spectroscopy (XAFS) were used to investigate the crystal and electronic properties of boron-substituted CuFeO2 material at room temperature. Without boron substitution, the polycrystalline structures of the trigonal (rhombohedral) ' $R\bar{3}m$ R 3 ¯ m ' CuFeO2 (87.7%) and hexagonal 'P63/mmc' (12.3%), which were also present in each sample but in different proportions, were utilised to identify the base material. XRD patterns revealed that, beyond 10% boron substitution, the metal–oxygen bonds (Fe-O and Cu-O) weakened, resulting in the formation of new tetragonal 'I41/amd' CuFe2O4 crystals. Although the CuFeO2 structure was preserved, it is conceivable that the presence of other crystal structures could lead to the formation of new features. This state arose as a result of CuFe2O4 crystallization and the impact of boron activity on the surrounding oxygen structures. By measuring magnetisation at both swept temperatures (10–300 K) and applied magnetic fields (±30 kOe), the magnetic properties of the samples were investigated. In the 10–300 K temperature range, the polycrystalline samples exhibit a ferromagnetic property without a magnetic phase transition. This suggests that replacing B with Fe in CuFe1−xBxO2 does not influence the primary magnetic property of CuFeO2. The samples' saturation magnetisation (Ms) values gradually fall as the B substitution content increases with Fe. This is because there's a chance that the non-transition metal B in CuFe1−xBxO2 will boost antiferromagnetic superexchange Cu-O interactions while lowering the p-d exchange interaction. [ABSTRACT FROM AUTHOR]

Lop Nur is located at the eastmost end of the Tarim Basin in Xinjiang, Northwestern China. This study reviews the hydrochemical characteristics and evolution of underground brine in Lop Nur, based on analytical data from 429 water samples (mainly brine). It is found that in the NE–SW direction, from the periphery to the Luobei sub‐depression, while the hydrochemical type varies from the sodium sulfate subtype (S) to the magnesium sulfate subtype (M), the corresponding brine in the phase diagram transfers from the thenardite phase (Then) area, through the bloedite phase (Blo), epsomite phase (Eps), picromerite phase (Picro), finally reaching the sylvite phase (Syl) area. As for the degree of evolution, the sequence is the periphery < Luobei horizontally and the overlying glauberite brine < the underlying clastic brine vertically. It is concluded that the oxygen and hydrogen isotopic compositions of the brine have evidently been affected through the effects of evaporation and altitude, as well as the changes in local water circulation in recent years. Boron and chloride isotopic compositions show that the glauberite brine is formed under more arid conditions than the clastic one. The strontium isotopic composition indicates that the Lop Nur brine primarily originates from surface water; however, deep recharge may also be involved in the evolution of the brine, according to previous noble gas studies. It is confirmed that the brine in Lop Nur has become enriched with potassium prior to halite precipitation over the full course of the salt lake's evolution. Based on chemical compositions of brine from drillhole LDK01 and previous lithological studies, the evolution of the salt lake can be divided into three stages and it is inferred that the brine in Lop Nur may have undergone at least two significant concentration‐dilution periods. [ABSTRACT FROM AUTHOR]

The world-class deposits of the Kalahari Manganese Field (KMF) in South Africa constitute a key resource of manganese (Mn) ore for the global steel industry. Many aspects of the origin of high metal-grade ores in the northernmost KMF remain unresolved, especially with respect to the complex hydrothermal history of these ores and the source/s of fluids responsible for epigenetic metal enrichment. In this study, the geochemistry of boron (B) is employed as a potential proxy for such processes, and the results are contextualised against an assumed low metalgrade precursor. Samples collected from the northern part of the Kalahari Manganese Deposit allow for the distinction of three Mn ore types, of which the precursor ore is the closest candidate, petrographically and geochemically, to primary/diagenetic Mn deposition. This precursor ore is dominated by Mn-carbonate and braunite, and records B concentrations in the order of a few 100s to 1 000s ppm and positive δ11B values at an average of 11 ± 6?. Ferruginous Mn ores appear to have formed from decarbonation of precursor ore and metasomatic ferric iron addition, particularly in the stratigraphically upper Mn ore bed, which is closest to the overlying Olifantshoek and Kalahari unconformities. Ferruginous Mn ores appear depleted in B (ca. 500 ppm on average) and have lower boron isotope values (δ11B: 0 ± 3?). Hydrothermally Mn-enriched ores, in contrast, are dominated by hausmannite, braunite-II and bixbyite and record highest B concentrations (up to 10 000s ppm) and δ11B values as high as 41?, pointing to metasomatic introduction of B by circulating evaporitic brines. While further research is needed to comprehensively unravel the geochemical intricacies of B within the complex interplay of fluids and rocks in the Hotazel region, the findings of this study still strongly suggest that B holds promise as a tracer for alteration processes in the KMF. [ABSTRACT FROM AUTHOR]

The boron isotope ratio of seawater (δ11Bsw) is a parameter which must be known to reconstruct palaeo pH and CO2 from boron isotope measurements of marine carbonates. Beyond a few million years ago, δ11Bsw is likely to have been different to modern. Palaeo δ11Bsw can be estimated by simultaneously constraining the vertical gradients in foraminiferal δ11B (Δδ11B) and pH (ΔpH). A number of subtly different techniques have been used to estimate ΔpH in the past, all broadly based on assumptions about vertical gradients in oxygen, and/or carbon, or other carbonate system constraints. In this work we pull together existing data from previous studies, alongside a constraint on the rate of change of δ11Bsw from modeling. We combine this information in an overarching statistical framework called a Gaussian Process. The Gaussian Process technique allows us to bring together data and constraints on the rate of change in δ11Bsw to generate random plausible evolutions of δ11Bsw. We reconstruct δ11Bsw, and by extension palaeo pH, across the last 65Myr using this novel methodology. Reconstructed δ11Bsw is compared to other seawater isotope ratios, namely Sr87/86 ${}^{87/86}\mathrm{S}\mathrm{r}$, Os187/188 ${}^{187/188}\mathrm{O}\mathrm{s}$, and δ7Li, which we also reconstruct with Gaussian Processes. Our method provides a template for incorporation of future δ11Bsw constraints, and a mechanism for propagation of uncertainty in δ11Bsw into future studies. Plain Language Summary: Boron naturally exists in two forms—11B and 10B. Measuring the ratio of these two forms of boron within marine shells allows us to estimate how alkaline the ocean was in the past, which is related to how much carbon dioxide is in the atmosphere. Before we can do this calculation though, we need to know some other parameters, one of which is the relative abundance of the two forms of boron in the ocean at the time (which we call δ11Bsw). Preexisting studies have estimated δ11Bsw at particular times, and here we combine them to generate a full reconstruction across the last 65 million years, accounting for uncertainties. Our reconstruction is informed by limiting the rate at which δ11Bsw can change, based on model simulations. We provide a set of plausible evolutions of δ11Bsw which can be used in future work when calculating past ocean pH. Key Points: We reconstruct the temporal evolution of seawater isotope ratios of boron, strontium, lithium, and osmium over the last 65 million yearsThe evolution of seawater boron isotope ratio shows similarity to the evolution of strontium, lithium and osmium isotope ratiosRandomly drawn, smooth time series are provided for use in uncertainty propagation in calculation of palaeo pH [ABSTRACT FROM AUTHOR]

Data on Stark broadening parameters, spectral line widths, and shifts for 15 multiplets of N VI, whose spectral lines are broadened by collisions with electrons, protons, alpha particles (He III) and B III, B IV, B V and B VI ions, are presented. They have been calculated using the semiclassical perturbation theory, for temperatures from 50,000 K to 2,000,000 K, and perturber densities from 1016 cm−3 up to 1024 cm−3. The data for e, p and He III are of particular interest for the analysis and modelling of atmospheres of hot and dense stars, as, e.g., white dwarfs, and for investigation of their spectra, and data for boron ions are used for analysis and modelling of laser-driven plasma in proton–boron fusion research. Dataset: The dataset is submitted as a Supplementary File. Dataset License: CC-BY 4.0 [ABSTRACT FROM AUTHOR]

This work presents the impact of the glass matrix Sb 2 O 3 –NiO–Na 2 O–B 2 O 3 on the structure, optical and ligand field parameters of Ni cations inside this glass system. Also, the radiation shielding properties of this glass system were investigated. The Sb 2 O 3 concentrations varied from 0 to 18 mol%, while Na 2 O and NiO were fixed at 19.6 and 0.9 mol%, respectively. The structural analyses confirmed that the glass density changed from 2.13 to 2.76 g/cm3, the molar volumes increased from 31.88 to 39.18 cm3/mol and N 4 ratio (tetrahedrally coordinated boron atoms) decreased from 41.16% to 29.65% with further Sb 2 O 3 /B 2 O 3 contents. The brown color of the glass samples and the absorption band at 419–427 nm also showed that Ni2+ cations in the form of NiO 6 units are present in this glass system. Furthermore, additional Sb 2 O 3 /B 2 O 3 contents moved the fundamental absorption edge toward higher wavelengths, reducing optical band gaps from 3.32 eV to 2.89 eV. Furthermore, the nonlinear refractive index increases with the increased Sb 2 O 3 /B 2 O 3 ratios. Also, Ni ions' ligand field splitting and Racah parameters showed different behaviors. In detail, the ligand field splitting showed decreased behavior from 7434 cm−1 to 7408 cm−1, whereas the Racah parameters showed increased behavior from 907 cm−1 to 942 cm−1. The obtained results support the tendency of the bonds between the Ni ions and their environments toward an ionic nature. Besides, the radiation shielding investigations showed enhanced parameters with further Sb 2 O 3 additives. Further, with increasing Sb 2 O 3 from 0 mol% to 18 mol%, there are increases in the mass attenuation coefficient values. The improved radiation shielding parameters of the studied glass samples propose them for ionizing radiation shielding applications. [ABSTRACT FROM AUTHOR]

Heavy metal poisoning has a life-threatening impact on the human body to aquatic ecosystems. This necessitates designing a convenient green methodology for the fabrication of an electrochemical sensor that can detect heavy metal ions efficiently. In this study, boron (B) and nitrogen (N) co-doped laser-induced porous graphene (LIGBN) nanostructured electrodes were fabricated using a direct laser writing technique. The fabricated electrodes were utilised for the individual and simultaneous electrochemical detection of lead (Pb2+) and cadmium (Cd2+) ions using a square wave voltammetry technique (SWV). The synergistic effect of B and N co-doping results in an improved sensing performance of the electrode with better sensitivity of 0.725 µA/µM for Pb2+ and 0.661 µA/µM for Cd2+ ions, respectively. Moreover, the sensing electrode shows a low limit of detection of 0.21 µM and 0.25 µM for Pb2+ and Cd2+ ions, with wide linear ranges from 8.0 to 80 µM for Pb2+ and Cd2+ ions and high linearity of R2 = 0.99 in case of simultaneous detection. This rapid and facile method of fabricating heteroatom-doped porous graphene opens a new avenue in electrochemical sensing studies to detect various hazardous metal ions. [ABSTRACT FROM AUTHOR]

Boronate esters are a class of compounds containing a boron atom bonded to two oxygen atoms in an ester group, often being used as precursors in the synthesis of other materials. The characterization of the structure and properties of esters is usually carried out by UV-visible, infrared, and nuclear magnetic resonance (NMR) spectroscopic techniques. With the aim to better understand our experimental data, in this article, the density functional theory (DFT) is used to analyze the UV-visible and infrared spectra, as well as the isotropic shielding and chemical shifts of the hydrogen atoms 1H, carbon 13C and boron 11B in the compound 4-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)benzaldehyde. Furthermore, this study considers the change in its electronic and spectroscopic properties of this particular ester, when its boron atom is coordinated with a fluoride anion. The calculations were carried out using the LSDA and B3LYP functionals in Gaussian-16, and PBE in CASTEP. The results show that the B3LYP functional gives the best approximation to the experimental data. The formation of a coordinated covalent B–F bond highlights the remarkable sensitivity of the NMR chemical shifts of carbon, oxygen, and boron atoms and their surroundings. Furthermore, this bond also highlights the changes in the electron transitions bands n → π* and π → π* during the absorption and emission of a photon in the UV-vis, and in the stretching bands of the C=C bonds, and bending of BO2 in the infrared spectrum. This study not only contributes to the understanding of the properties of boronate esters but also provides important information on the interactions and responses optoelectronic of the compound when is bonded to a fluorine atom. [ABSTRACT FROM AUTHOR]

Boron, as both a lithophilic and biophilic element with high solubility, provides profound insights into the history of the Earth and environmental changes through its isotopes present in sediments. However, there are still some challenges in the accurate and precise determination of boron isotopes in sediments, particularly in pre-processing. When using boron-specific resins for the purification and enrichment of boron, it is in an alkaline environment. During the pre-treatment process, insoluble hydroxides of Al, Fe, and rare earth elements precipitate, exhibiting strong boron adsorption in high-pH solutions. This has potential impacts on the accuracy of boron isotope measurements. This study assesses a method that uses Na2CO3 and K2CO3 for dissolution at reduced temperatures and a cationic resin combined with a boron-specific resin for the enrichment and purification of boron in sediments. All the Al, Fe, and rare earth elements, which can generate water-insoluble hydroxides, were mainly removed by the cationic resin column, and boron in the sample solutions without Al, Fe, and rare earth elements was extracted by the boron-specific resin. The boron isotope composition (δ11B) was determined using MC-ICP-MS. The results indicate that this method fully decomposes and efficiently purifies the sediments. The long-term instrumental external reproducibility of δ11B values for NIST SRM 951a, ERM-AE120, and ERM-AE121 were 0.01 ± 0.09‰ (n = 13), −20.28 ± 0.16‰ and 19.98 ± 0.14‰, based on the measurements using a series of international reference materials over the last three years. The measured δ11B values for the standards have various matrices. The δ11B values of GSR-1 (−13.14‰ ± 0.27‰), BHVO-2 (−0.66 ± 0.06‰), AGV-2 (−3.22 ± 0.14‰) and Nass-6 (39.83 ± 0.07‰) are in agreement with the published data within uncertainty. The samples from Sihailongwan Maar Lake (SMK), the Loess Plateau (Loess-1 and Loess-2), shale (SH-1 and SH-2), and basalt (BL-1 and BL-2) were treated. The δ11B values for SMK, Loess-1, and Loess-2 are −10.20 ± 0.29‰, −11.06 ± 0.16‰, and −10.79 ± 0.10‰, showing a close relationship with δ11B of the continental crust. The δ11B values for shale (SH-1 and SH-2) are −7.06‰ ± 0.32‰ and +2.28‰ ± 0.05‰, while those for basalt (BL-1 and BL-2) are −8.78‰ ± 0.09‰ and +2.50‰ ± 0.19‰. These results indicate a significant variation in the δ11B values across these samples. These findings imply that this approach is capable of efficiently enriching and purifying boron in sediments. It enables accurate and precise determination of δ11B in sediments, thus offering a reliable tool for conducting boron isotope studies in sedimentary earth science. [ABSTRACT FROM AUTHOR]

Subduction zones are critical sites for recycling of Li and B into the mantle. The way of redistribution of Li and B and their isotopes in subduction settings is debated, and there is a lack of detailed studies on Li and B partitioning between minerals of different types of eclogites and the host rocks of the eclogites. We present Li and B concentration data of minerals and Li and B whole-rock isotope data for low-T and high-T eclogites and their phengite schist host rocks from the Changning–Menglian suture zone, SW China. Omphacite controls the Li budget in both the low-T and high-T eclogites. Low-T eclogites have Li and δ7Li values (8.4–27.0 ppm, – 5.5 to + 3.2 ‰) similar to the phengite schists (8.7–27.0 ppm, – 3.8 to + 3.0 ‰), suggesting that Li was added to low-T eclogites from the phengite schists. In contrast, high-T eclogites have much lower δ7Li values (– 13.2 to – 5.8 ‰) than the phengite schists, reflecting prograde loss of Li or exchange with wall rocks characterized by low δ7Li values. Phengite and retrograde amphibole/muscovite are the major B hosts for low-T and high-T eclogites, respectively. The budgets and isotopic compositions of B in eclogites are affected by the infiltration of fluids derived from phengite schists, as indicated by eclogite δ11B values (– 15.1 to – 8.1 ‰) overlapping with the values of the phengite schists (– 22.8 to – 9.5 ‰). Lithium and B in eclogites are hosted in different mineral phases that may have formed at different stages of metamorphism, implying that the contents and isotopic compositions of Li and B may become decoupled during subduction-related fluid-mediated redistribution. We suggest a mineralogical control on the redistribution of Li and B in eclogites during subduction and the exchange of Li and B with the immediate wall rocks. The observed contrasting Li and B isotopic signatures in eclogites are likely caused by a fluid-mediated exchange with different types of wall rocks during both prograde metamorphism and exhumation. [ABSTRACT FROM AUTHOR]

The effect of substituents of various natures at boron atoms in different positions of the carborane cage on the CH-acidity of carborane derivatives and the electron-withdrawing effect of C-carboranyl groups is considered using 1H NMR spectroscopy data. [ABSTRACT FROM AUTHOR]

A prominent seismic weakening has suggested the potential presence of H 2 O-bearing complex silicate melts in the Earth's interiors. As boron is typically accompanied by the hydrous fluids and melts and may be transported into deep mantle, boron isotopic evolution enables us to trace the deep-water cycle. The impact of H 2 O on the structures of boron-bearing magmas is essential to grasp the melting processes and the seismic weakening in Earth's mantle. In this study, we report experimental results on the structural changes in volatile-bearing, partially-depolymerized aluminoborosilicate glasses (NaAl 0.5 B 0.5 Si 3 O 8) - an analog for boron-rich rhyolitic melts - with varying H 2 O content and at pressure conditions from 6 to 8 GPa (∼180–240 km depth in the mantle) via multi-nuclear (1H, 17O, 27Al, 11B, 29Si, and 23Na) magnetic resonance (NMR) spectroscopy. At isobaric conditions both at 6 GPa and 8 GPa, compared to the coordination environments of anhydrous quenched melts, adding water up to 4 wt% generally promotes the formation of [4]B and systematically suppresses the [5,6]Al fractions; however, in the glasses with 8 wt% water (at 8 GPa), a dramatic increase in both [6]Al and [4]B is observed, while Si coordination number remains unchanged. In contrast, at a constant H 2 O content of 4 wt%, an increase in the pressure from 6 to 8 GPa results in an increase in the [5,6]Al fractions and a decrease in the [4]B fraction. The results highlight complex water-pressure dependences on the cation coordination transformation. Upon adding water content at isobaric condition, boron is more prone to be highly-coordinated over aluminum. In contrast, with increasing pressure at a constant water content, aluminum prefers to be highly-coordinated over boron. These NMR results allow us to refine water dissolution schemes, highlighted by selective network depolymerization of B and Al-bearing bridging oxygens and subsequent annihilation of oxygen triclusters consisting primarily of Al, consistent with a water-driven evolution of B-Al coordination numbers in response to pressurization. These changes induce non-linear decrease in melt viscosity and seismic weakening in the mantle at depths of ∼180–240 km. Observed boron coordination evolutions indicate that deep mantle melts could exhibit complex pressure-water-driven changes in the tendency to enrich 10B. In particular, the effect of 8 wt% water contributes to ∼41 % of the overall reduction of δ11B in deep melts. Finally, as the deep magmatic melts could also be more mafic than those studied here, the water-driven structural changes in more mafic melts with much less boron contents under compression remain to be explored. While the details may vary with melt composition, the current probing of the structures of boron-bearing compressed melts with varying degree of hydration enables better prediction of the deep boron and water cycles. [ABSTRACT FROM AUTHOR]

In this work, a new analysis of the isotopic composition of boron nuclei (B) in galactic cosmic rays (GCRs) in the range of rigidities of 1–5 GV (nuclear energies 0.1–1.5 GeV/nucleon) was carried out using data from the PAMELA space experiment 2006–2014 on the rigidity of detected nuclei and their velocity (time-of-flight analysis and ionization losses in the instrument's multilayer calorimeter). The new results of the PAMELA experiment expand the energy range of previous measurements, are consistent with the few existing data, and indicate deviations of the B isotope ratios from the GALPROP simulation data for the GCR, similar to the deviations for the Li and Be isotopes in the PAMELA data, which can be interpreted as evidence of observation against the background of the GCR of the contribution of several local sources from explosions of nearby (hundreds of parsecs) supernovae. [ABSTRACT FROM AUTHOR]

Experimental studies of intentionally doped impurities for the understanding of conductivity control in hexagonal boron nitride (h-BN) ultrawide bandgap (UWBG) semiconductor are limited but are highly desired for emerging applications of h-BN. We report synthesis by hydride vapor phase epitaxy and comparison photoluminescence (PL) emission spectroscopy studies of intentionally carbon (C)-doped and undoped h-BN semi-bulk crystals. In addition to the well-known C-related emission lines observed previously, a C-impurity-related transition near 1.31 eV consisting of multiple phonon replicas has been observed in C-doped h-BN at room temperature. Phonon replicas involved in the 1.31 eV emission have been identified using polarization resolve PL spectroscopy as the transverse acoustic (TA)/longitudinal acoustic (LA) and out-of-plane optical phonon (ZO) modes at the middle point, T, between the Γ- and K-points in the first Brillouin zone. Based on the agreement between the spectral peak position of the observed dominant emission line at 1.31 eV and the calculated energy-level separation between CB donor (carbon replacing boron) and Ci acceptor (carbon interstitial), the observed IR emission line can be decisively assigned to the donor–acceptor pair (DAP) transition involving the CB donor and Ci acceptor assisted by the intervalley (Κ → Μ) scattering processes. The results reinforce the perception that C impurities form deep-level centers and provided an improved understanding of C impurities in h-BN. [ABSTRACT FROM AUTHOR]

L-4-[(10B)]Boronophenylalanine (BPA) is an amino acid analogue with a boron-10 moiety. It is most widely used as a boron carrier in boron neutron capture therapy. In this study, a Bayesian predictive platform of blood boron concentration based on a BPA pharmacokinetic (PK) model was developed. This platform is user-friendly and can predict the individual boron PK and optimal time window for boron neutron capture therapy in a simple way. The present study aimed to establish a PK model of L-4-boronophenylalanine and develop a Bayesian predictive platform for blood boron PKs for user-friendly estimation of boron concentration during neutron irradiation of neutron capture therapy. Whole blood boron concentrations from seven previous reports were graphically extracted and analyzed using the nonlinear mixed-effects modeling (NONMEM) approach. Model robustness was assessed using nonparametric bootstrap and visual predictive check approaches. The visual predictive check indicated that the final PK model is able to adequately predict observed concentrations. The Shiny package was used to input real-time blood boron concentration data, and during the following irradiation session blood boron was estimated with an acceptably short calculation time for the determination of irradiation time. Finally, a user-friendly Bayesian estimation platform for BPA PKs was developed to optimize individualized therapy for patients undergoing BNCT. [ABSTRACT FROM AUTHOR]

The article explores the formation and journey of superdeep diamonds, originating from depths of approximately 300–800 kilometer below the Earth's surface, and investigates the mechanisms by which they are transported to the surface through kimberlites. It discusses the challenges of dating these diamonds and presents a recent study that sheds light on their ages, suggesting a lengthy storage period in the mantle before reaching the surface.

Boron trace determination in biological materials is needed in different fields of application. Direct B determination by means of Graphite Furnace Atomic Absorption Spectrometry (SS-GFAAS) has been used in the past for this purpose, offering good detection limits hardly achievable by other techniques. However, such methods require the use of high atomization temperatures combined with large integration times to promote B atomization, which dramatically reduces the lifetime of the instrument's graphite parts. In this work, a new perspective for B determination by means of Graphite Furnace Molecular Absorption Spectrometry (GFMAS) is proposed. B was detected as the diatomic molecule BF (boron monofluoride), deploying a gas phase reaction with CH3F as fluorinating agent. Based on this strategy, a method for the direct determination of B in two biological certified reference materials (NIST SRM 1570a spinach leaves and NIST SRM 1573a tomato leaves) has been developed, providing similar detection capabilities to the GFAAS method (LOD of 0.24 ng) but requiring much milder furnace conditions. Moreover, the appearance of memory effects, very common in GFAAS methods, is also avoided with this method. Straightforward calibration with aqueous standard solutions was also found to be possible. To this end, a mixture of W (permanent), citric acid, and Ca as chemical modifiers was found to be essential for obtaining a reproducible and sufficiently sensitive signal for boron solutions, comparable to the signals obtained for the solid samples. With this method, accurate results were obtained for the direct analysis of both certified reference materials, provided that spectral interferences from the PO molecule were properly corrected. Precision values in the range of 15% RSD, as typically reported for direct solid sampling GFAAS, were found. Finally, and as an additional advantage of the GFMAS method, a large isotopic shift in the absorbance of the 10BF and 11BF molecules can be accurately monitored at a secondary transition for the BF molecule. This offers novel analytical possibilities for the method, which are also explored in this study. In this regard, control of the B concentration was found to be critical for obtaining accurate and precise isotope ratios for this element. [ABSTRACT FROM AUTHOR]

Veloso is one of numerous and poorly documented auriferous deposits of Ouro Preto, the town that symbolises the gold rush in Brazil at the turn of the seventeenth century. We present the results of underground geological mapping, combined with a boron (B) isotopic study of tourmaline, an elusive mineral in the auriferous quartz lode of the historical Veloso deposit. Its lode is characteristically brecciated in a host rock that shows no cataclastic fabric. The host rock is itabirite, a metamorphosed banded iron formation. Tourmaline is essentially dravite and locally occurs as abundant crystals in breccia-cementing pockets of goethite, formed from the oxidation of sulfide minerals. Gold is spatially associated with tourmaline in the goethite-rich pockets. In situ measurements for B isotopes yielded δ11B values in the range of −21 to −9‰. This range is similar to that reported for tourmaline of the Passagem de Mariana deposit, the best documented auriferous lode deposit at the south-eastern edge of the Quadrilátero Ferrífero. The tourmaline B isotopic data reflect auriferous fluids of crustal origin that sourced B from metasedimentary rocks, which may include a non-marine evaporitic component. [ABSTRACT FROM AUTHOR]

Solution MC‐ICP‐MS is an established technique for high precision boron isotope measurement results (δ11BSRM 951) in carbonates, yet its application to silicate rocks has been limited. Impediments include volatilisation during silicate dissolution and contamination during chemical purification. To address this, we present a low‐blank sample preparation procedure that couples hydrofluoric acid‐digestion and low‐temperature evaporation (mannitol‐free), to an established MC‐ICP‐MS measurement procedure following chemical purification using B‐specific Amberlite IRA 743 resin. We obtain accurate δ11BSRM 951 values (intermediate precision ±0.2‰) for boric acid (BAM ERM‐AE121 19.65 ± 0.14‰) and carbonate (NIST RM 8301 (Coral) 24.24 ± 0.11‰) reference materials. For silicate reference materials covering mafic to felsic compositions we obtain δ11BSRM 951 with intermediate precision < ±0.6‰ (2s), namely JB‐2 6.9 ± 0.4‰; IAEA‐B‐5 ‐6.0 ± 0.6‰; IAEA‐B‐6 ‐3.9 ± 0.5‰ (2s). Furthermore, splits of these same reference materials were processed by an alternative fusion and purification procedure. We find excellent agreement between δ11BSRM 951 measurement results by MC‐ICP‐MS of the reference materials using both sample processing techniques. These measurement results show that our sample processing and MC‐ICP‐MS methods provide consistent δ11BSRM 951 values for low B‐mass fraction samples. We present new data from Mid Ocean Ridge Basalt (MORB) glass, documenting a range in δ11BSRM 951 from ‐5.6 ± 0.3‰ to ‐8.8 ± 0.5‰ (2s), implying some upper mantle δ11BSRM 951 heterogeneity. [ABSTRACT FROM AUTHOR]

The well-preserved Ashele subseafloor replacement-style volcanogenic massive sulfide (VMS) deposit in the Central Asian Orogenic Belt comprises two stages of Cu mineralization, i.e., early massive sulfides dominated by colloform and euhedral pyrite intergrown with chalcopyrite and sphalerite, which were replaced by late vein-dominated chlorite-chalcopyrite assemblages. In this study, a combined systematic Fe, B, and S isotope investigation was first applied to investigate the sulfide precipitation processes and the relative proportion of fluid sources in different alteration and mineralization stages of the Ashele deposit. Boron isotopes of Mg-rich tourmaline (δ11B from -5.57‰ to -2.73‰, average (avg.) -4.23‰) indicate significant seawater (∼19%) participated during the formation of massive sulfides. A two-component mixing model is used to estimate the contribution of seawater and igneous sulfur to the total sulfur budget, and the results show the increasing contribution of magmatic sulfur from the early (35%) to late (76%) stages. In addition, δ56Fe values of pyrite gradually increase from the massive ore (-0.46‰ to -0.02‰, avg. -0.24‰), quartzpyrite (-0.09‰ to 0.07‰, avg. -0.01‰), chlorite-chalcopyrite-quartz-pyrite (0‰ to 0.21‰, avg. 0.08‰) to the quartz-sericite zone (-0.02‰ to 0.29‰, avg. 0.14‰), which is likely related to the different extent of isotopic exchange and formation temperature, and could be used in the exploration of VMS systems. The new two-stage ore-forming model shows that in the early stage, rapid mixing of hydrothermal fluid from underlying magma chamber with abundant cold seawater led to rapid deposition of pyrite and associated Cu mineralization under relatively oxidized condition, and long-term hydrothermal activities in relatively closed systems would promote the formation of upper massive ores, which resulted in an equilibrium system between pyrite, chalcopyrite, and associated fluid with wide ranges of δ56Fe in pyrite (-0.46‰ to -0.02‰) and chalcopyrite (-1.56‰ to -0.49‰). The late hydrothermal activities in relatively open system would contribute to stringer sulfides or stockworks underlying the massive ore in relatively reduced conditions with heavier Fe isotope compositions in pyrite (-0.09‰ to 0.29‰) and chalcopyrite (-0.60‰ to - 0.04‰). Overall, our study demonstrates that the coupling of B, Fe, and S isotopes could be a useful tool to indicate long-term subseafloor infilling and replacement processes for subseafloor replacementtype VMS deposits, which are the prerequisite to form large-tonnage VMS deposits. [ABSTRACT FROM AUTHOR]

Arc magmas are produced from the mantle wedge, with possible addition of fluids and melts derived from serpentinites and sediments in the subducting slab. Identification of various sources and their relevant contributions to such magmas is challenging; in particular, at continental arcs where crustal assimilation may overprint initial geochemical signatures. This study presents oxygen isotopic compositions of zoned olivine grains from post-caldera basalts and boron contents and isotopes of these basalts and glassy melt inclusions hosted in quartz and clinopyroxene of silicic tuffs in the Toba volcanic system, Indonesia. High-magnesian (≥87 mol% Fo [forsterite]) cores of olivine in the basalts have δ18O values ranging from 5.12‰ to 6.14‰, indicating that the mantle source underneath Toba is variably enriched in 18O. Olivine with <87 mol% Fo has highly variable (4.8-7.2‰), but overall increased, δ18O values, interpreted to reflect assimilation of high δ18O crustal materials during fractional crystallization. Mass balance calculations constrain the overall volume of crustal assimilation for the basalts as ≤13%. The processes responsible for the 18O-enriched basaltic melts are further constrained by boron data that indicate the addition of <0.1 wt% fluids to the mantle, >40% of the fluids being derived from serpentinites and others from altered oceanic crust and sediments. This amount of fluids can increase δ18O of the magma by only ∼0.02‰. Approximately 6-9% sediment-derived melt hybridization in the mantle wedge is further needed to yield basaltic melts with δ18O values in equilibrium with those of the high-Fo olivine cores. The cogenetic silicic tuffs, on the other hand, seem to record a higher proportion of fluid addition dominated by sediment-derived fluids to the mantle source, in addition to crustal assimilation. Our reconnaissance study therefore demonstrates the application of combined B and O isotopes to differentiate between melts and fluids derived from serpentinites and sediments in the subducted slab-an application that can be applied to arc magmas worldwide. [ABSTRACT FROM AUTHOR]

Boron (B) isotopes are widely used in the Earth sciences to trace processes ranging from slab recycling in the mantle to changes in ocean pH and atmospheric CO2. Boron isotope analysis is increasingly achieved by multi‐collector inductively coupled plasma mass spectrometry, which requires separation of B from the sample matrix. Traditional column chromatography methods for this separation have a well‐established track record but are time consuming and prone to contamination from airborne blank. Here, we present an extensive array of tests that establish a novel method for B purification using a batch method. We discuss the key controls and limitations on sample loading, matrix removal and B elution including sample volume, ionic strength, buffer to acid ratio and elution volume, all of which may also help optimize column‐based methods. We find consistent, low procedural blanks of 10 ± 16 pg and excellent reproducibility: 10 ng NIST RM 8301 foram [8301f] yields 14.58 ± 0.11‰ 2SD n = 15; 2.5 ng 8301f yields 14.60 ± 0.19‰ 2SD, n = 31; and overall long term 2SD on n = 218 samples pooling different sample sizes yields 14.62 ± 0.21‰ 2SD. This method also offers significant advantages in throughput, allowing the processing of 24 samples in ∼5 hr. This boron batch method thus provides a fast, reproducible, low‐blank method for purification of boron for high precision isotopic analyses. Key Points: Optimized method for B purification for δ11B analysis by multi‐collector inductively coupled plasma mass spectrometryAllows faster sample processing (24 samples in ∼5 hr)Minimizes procedural blanks (typically <20 pg) [ABSTRACT FROM AUTHOR]

The Altiplano-Puna Plateau of the Central Andes hosts numerous lakes, playa-lakes, and salars with a great diversity and abundance of carbonates forming under extreme climatic, hydrologic, and environmental conditions. To unravel the underlying processes controlling the formation of carbonates and their geochemical signatures in hypersaline systems, we investigated coupled brine-carbonate samples in a high-altitude Andean lake using a wide suite of petrographic (SEM, XRD) and geochemical tools (δ2H, δ18O, δ13C, δ11B, major and minor ion composition, aqueous modelling). Our findings show that the inflow of hydrothermal springs in combination with strong CO 2 degassing and evaporation plays an important role in creating a spatial diversity of hydro-chemical sub-environments allowing different types of microbialites (microbial mounds and mats), travertines, and fine-grained calcite minerals to form. Carbonate precipitation occurs in hot springs triggered by a shift in carbonate equilibrium by hydrothermal CO 2 degassing and microbially-driven elevation of local pH at crystallisation. In lakes, carbonate precipitation is induced by evaporative supersaturation, with contributions from CO 2 degassing and microbiological processes. Lake carbonates largely record the evaporitic enrichment (hence salinity) of the parent water which can be traced by Na, Li, B, and δ18O, although other factors (such as e.g., high precipitation rates, mixing with thermal waters, groundwater, or precipitation) also affect their signatures. This study is of significance to those dealing with the fractionation of oxygen, carbon, and boron isotopes and partitioning of elements in natural brine-carbonate environments. Furthermore, these findings contribute to the advancement in proxy development for these depositional environments. [ABSTRACT FROM AUTHOR]