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Abstract This study investigates the potential of laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) U‐Pb dating for carbonate nodules in the Late Triassic Ischigualasto Formation of northwestern Argentina. We establish a fully characterized paragenetic sequence to guide the analysis of three pedogenic carbonates and compare the U‐Pb ages with published geochronology from volcanic ashes within the sedimentary succession. Our findings demonstrate the importance of interpreting U‐Pb data within a well‐defined paragenetic framework for accurate age interpretation of pedogenic carbonates. We observe variations in U‐Pb isotopic signatures across different generations of carbonate precipitates and identify syn‐pedogenic and early burial calcite cements as most suitable for precise dating. Respectively, these two calcite cements are interpreted as microcodium and crack‐lining calcite cements formed early in the paragenetic sequence during pedogenesis to early burial of the paleosols as they transitioned from the unsaturated vadose to saturated phreatic zone below the water table. The U‐Pb ages obtained from the carbonate nodules agree with the radioisotopic ages of volcanic ashes, supporting the validity of our dating strategy. These results contribute to advancing U‐Pb carbonate geochronology and highlight its increased potential for dating sedimentary records in the terrestrial realm. Future research should focus on replicating similar work on different carbonate nodules within the Ischigualasto Fm and expanding the application of LA‐ICP‐MS U‐Pb dating to other carbonate‐bearing formations, especially in successions with limited absolute ages or where volcanic ashes are sparse or absent.

A promising primary reference material for U–Pb laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) carbonate dating is analysed and reported here. The new reference material (RM) is a botryoidal cement (C1) from sample RA138. The sample was collected in outcrop strata of mid-Carboniferous age in northern Spain near La Robla, and multiple aliquots have been meticulously prepared for distribution. RA138 is characterized by variable U/Pb ratios (from ∼ 1 to ∼ 19) and a relatively high and homogeneous U content (∼ 4 ppm). This material exhibits a low age uncertainty (0.2 %, 2 s; unanchored; ID-TIMS), allowing for the establishment of a well-defined isochron, particularly when anchored to the initial Pb ratio using LA-ICP-MS. Isotope dilution thermal ionization mass spectrometry (ID-TIMS) analyses of micro-drilled C1 cement (17 sub-samples) produce a lower-intercept age of 321.99 ± 0.65 Ma, an initial 207Pb/206Pb ratio of 0.8495 ± 0.0065, and a mean square weighted deviation (MSWD) of 5.1. The systematic uncertainty of 1.5 % observed in repeated LA-ICP-MS analyses challenges previous estimations of 2 %–2.5 % based on repeated analyses of ASH-15D and JT using WC-1 as primary reference material, underscoring the precision and reliability of RA138 for U–Pb dating applications.

Objectives Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has considerable applicative potential for both qualitative and quantitative analyses of elemental spatial distribution and concentration. It provides high resolutions at pg-level detection limits. These qualities make it very useful for analyzing biological samples. The present study responds to the growing demand for adequate analytical methods which would allow to assess the distribution of nanostructured molybdenum(IV) disulfide (MoS 2 ) in organs. It was also motivated by an apparent lack of literature on the biological effects of MoS 2 in living organisms. The study was aimed at using LA-ICP-MS for comparing micro- and nanosized MoS 2 ditribution in selected rat tissue samples (lung, liver, brain and spleen tissues) after the intratracheal instillation (7 administrations) of MoS 2 nano- and microparticles vs. controls. Material and Methods The experimental study, approved by the Ethics Committee for Animal Experiments was performed using albino Wistar rats. This was performed at 2-week intervals at a dose of 5 mg/kg b.w., followed by an analysis after 90 days of exposure. The MoS 2 levels in control tissues were determined with the laser ablation system at optimized operating conditions. The parameter optimization process for the LA system was conducted using The National Institute of Standards and Technology (NIST) glass standard reference materials. Results Instrument parameters were optimized. The study found that molybdenum (Mo) levels in the lungs of microparticle-exposed rats were higher compared to nanoparticle-exposed rats. The opposite results were found for liver and spleen tissues. Brain Mo concentrations were below the detection limit. Conclusions The LA-ICP-MS technique may be used as an important tool for visualizing the distribution of Mo on the surface of soft samples through quantitative and qualitative elemental mapping. Int J Occup Med Environ Health. 2024;37(1):18–33

Lanthanides (Lns) have been increasingly used in different fields, raising some concerns due to potential adverse effects to human life. In this work, it is proposed a laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) method for Lns determination in tea. Cellulose powder, leave powder and filter paper were evaluated as matrix matched standards and 13C, 103Rh, 115In, 197Au and 205Tl as internal standards (IS). Operating conditions of the LA-ICP-MS system, sample preparation procedures, and spiking samples with IS and standards were optimized. Better conditions of IS mixed with powdered standards or samples was achieved when the powder particles size was lower than 50 μm and 2 mL of IS or standard solutions were added to 500 mg of sample. Best results were obtained using Au as IS and filter paper. The method was applied to Lns determination in mint tea, where Ce, La and Nd concentrations were 580 ± 50, 282 ± 15 and 340 ± 60 ng g–1, respectively. The concentrations of the other Lns were below their limit of quantification (LOQ). The Lns concentrations determined by LA-ICP-MS were in good agreement (95% confidence level, t-test) with those found using ultrasonic nebulization-ICP-MS with a precision better than 20%.

Apatite is a widespread U-bearing mineral in igneous, metamorphic, and sedimentary rocks. U-Pb geochronology of apatite can provide significant information for constraining magmatic evolution processes and tracing provenance. Laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) is a crucial technique for in situ U-Pb age analysis of apatite. However, the lack of suitable matrix-matched apatite reference materials and the inevitable presence of common lead in reference materials are major obstacles restricting high-precision determination of apatite U-Pb ages. This study investigates the impact of common lead on LA-ICP-MS apatite U-Pb dating results. The significant systematic biases (6%−30%) in both measured lower intercept ages and initial lead compositions are observed when calibrating against MAD apatite without common lead correction. However, accurate apatite U-Pb ages (within 2% systematic bias) can be obtained by correcting for common lead in MAD using the 207Pb method or Tera-Wasserburg plot method prior to Pb/U fractionation calibration. Furthermore, a vapor-assisted laser ablation method is employed in conjunction with NIST612 glass as an external standard to accurately analyze apatite U-Pb ages. This non-matrix matched method eliminates the need to consider the influence of common lead in the reference materials. Novel high-precision LA-ICP-MS apatite U-Pb dating methods are established with both matrix-matched and non-matrix-matched analyses, which greatly promote the application of apatite U-Pb geochronology in Earth science. [ABSTRACT FROM AUTHOR]

[Display omitted] • Qiagong Fe skarn mineralization (51 Ma) linked to Early Eocene biotite monzogranite. • First evidence for an earlier Late Cretaceous Cu skarn mineralization at Jiaduobule. • Two major mineralization events: Fe–Cu–Pb–Zn–W–Mo (65–50 Ma); Cu(±Au) (∼85 Ma) • Good exploration prospects for Late Cretaceous Cu ± Au mineralization in Gangdese belt. Iron, Cu, Pb–Zn, and W–Mo skarn deposits occur in the Gangdese metallogenic belt, Tibet. A lack of precise age constraints for mineralization hinders understanding of the processes contributing to skarn mineralization, particularly identification of the causative intrusions. In this study, new garnet U–Pb geochronological data are provided for the Qiagong (Fe) and Jiaduobule (Fe–Cu) skarns. We place particular emphasis on skarn garnet mineralogy, using scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS), to characterize garnet textures, compositions, and U–Pb isotope systematics. All garnets studied belong to the grossular-andradite series and display oscillatory compositional zoning (And 100 Gr 0 to And 20 Gr 80). Andradite-dominated garnet features a chondrite-normalized REE fractionation pattern exhibiting enrichment in LREE relative to HREE and a positive Eu anomaly, whereas grossular-dominated garnet displays relative LREE depletion and a marked flat HREE fractionation trend. Ore-forming elements, including Sn, W, As, and U, are detected at concentrations up to several hundreds of ppm in the same garnets. Concentrations of W and As are higher in andradite and correlate positively with one another. The correlation between U, Sn and the major oxide composition of garnet is insignificant, potentially resulting from the changing valence states of these elements under different redox conditions. Together with previously published and limited new data for the Gebunongba (Fe), Ri'a (Cu), and Hahaigang (W–Mo) skarns, the new garnet U–Pb age data indicate that the major Fe, Pb–Zn, and W–Mo mineralization event in the Gangdese metallogenic belt took place between 65 Ma and 50 Ma, with marked peaks at ∼ 65 Ma and ∼ 53 Ma. Partial melting of a crustal-dominated source due to the slab rollback (∼65 Ma) and break off (∼53 Ma) of Yarlug–Zangbo Tethyan Ocean and subsequent asthenosphere upwelling induced this regional event during the Paleogene to early Eocene. A less common but regionally widespread Cu (±Au) mineralization event in the same belt formed during the Late Cretaceous (∼85 Ma) and may have resulted from the coupled influence of the northward subduction of the Yarlug–Zangbo Tethyan Ocean and the southward subduction of the Bangong–Nujiang Tethyan Ocean. This contribution highlights the potential significance of the Late Cretaceous Cu(±Au) event and hence the prospectivity of the belt for both skarn and porphyry systems. More broadly, our findings carry implications for Neo-Tethyan metallogeny in the region extending from southwestern China to eastern Europe during the Late Cretaceous. [ABSTRACT FROM AUTHOR]

In this paper, based on the research background of recovering uranium from wet-process phosphoric acid(WPA) by amino phosphonate acid chelating resin, the distribution of uranium in single particle amino phosphonate chelating resin was studied. The results show that the optimal laser frequency of LA-ICP-MS is determined to be 6 Hz, the beam spot diameter is 44 μm, and the energy density is 6 J/cm2. The resin with saturated adsorption and the resin with complete elution were selected as the external standard of the adsorption and leaching process, and the homogeneity test was carried out. The relative standard deviation of uranium content in the resin with saturated adsorption and the resin with complete elution are 3.87% and 3.52%(n=9), respectively. Uniformity is good. In situ microzone analysis of uranium in amino phosphonic acid chelating resin was carried out by LA-ICP-MS. The adsorption process of uranium on the resin is gradually completed from the outside to the inside, and the leaching process is gradually completed from the outside to the inside, and the concentration of uranium inside and outside the resin is gradually uniform and unified, and finally reaches adsorption saturation and leaching complete.