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Vesuvianite is a common accessory mineral that usually occurs in metamorphosed and metasomatised, argillaceous carbonate rocks (i.e., skarn rocks) and as a late crystallising phase in igneous rocks such as nepheline syenites. Vesuvianite is a Ca-rich mineral that preferentially incorporates Sr and light rare earth elements (LREEs). Given that vesuvianite is susceptible to alteration and commonly contains inclusions, in situ laser ablation analysis is the preferred approach for measuring its Sr–Nd isotopic compositions. The use of matrix-matched and homogeneous reference materials is a prerequisite for laser ablation isotope analyses. Two in-house vesuvianite standards M6635 and M659 were used for external correction during in situ laser ablation analysis for Sr and Nd isotopic compositions, respectively. In this paper, we apply in situ Sr and Sm–Nd isotope analyses for 11 vesuvianite samples (M6635, M784, M1377, M660, M1439, M1450, M6601, 13MDL176, Wilui, Hazlov, and Goodall) from different locations. The obtained Sr and Sm–Nd isotopic compositions for these vesuvianite samples are consistent with those obtained by solution-based methods using MC-ICP-MS, which demonstrates the robustness of our analytical methods. We recommend that samples M6635, M784, M1377, and M1450 are suitable vesuvianite reference materials for in situ Sr isotope analyses, and sample M659 is a potential vesuvianite reference material for in situ Sm–Nd isotope analyses. [ABSTRACT FROM AUTHOR]

Precise and accurate Fe isotope data of thirteen silicate minerals, including olivine, garnet, amphibole and biotite are reported here using the non-matrix-matched BCR-2G reference glass for isotope ratio calibration combined with a Ni doping method for instrumental mass bias correction by LA-MC-ICP-MS under wet-plasma conditions. All the in situ Fe isotope data are consistent with the recommended Fe isotopic values determined by SN-MC-ICP-MS. These results indicate that in situ Fe isotopic determinations by LA-MC-ICP-MS under wet-plasma conditions are matrix-independent for a variety of silicate minerals, and BCR-2G glass is suitable as the reference material for microbeam Fe isotopic analysis for silicate minerals. However, for other microbeam Fe isotopic analysis, e.g., SIMS, finding matrix-matched standards for data quality assurance is also required. Multiple analyses on two international olivine standards (San Carlos and ALM) and four natural silicate minerals (YY09-04 olivine, YS-13 garnet, YS-31 amphibole and Moosilauke biotite) reveal homogeneous Fe isotopic compositions with the external reproducibility better than 0.20‰ for δ56Fe values (2SD). Thus, these silicate minerals are proposed as matrix-matched in-house standards for isotope ratio calibrations and data quality control during microbeam Fe isotopic analysis. YY11-12 olivine, YS-42 garnet, YS-37 amphibole and YS-20 biotite with the external reproducibility of 0.23‰, 0.28‰, 0.23‰ and 0.25‰ for δ56Fe values (2SD), respectively, are only suitable as in-house standards for data quality monitoring during microbeam Fe isotopic analysis. [ABSTRACT FROM AUTHOR]

Apatite, an important mineral widely distributed in various geological environments, can be used for in situ U–Pb dating and Sr–Nd isotope analyses. The LA-ICPMS U–Pb dating and Sr–Nd isotopic determinations require suitable matrix-matched reference materials. Current apatite standards are rare and have some defects. Most natural apatite references display high and variable common Pb, which may be the most difficult issue in microbeam determination. We provided a gem-quality apatite MAP-3, subjected to detailed major- and trace element composition, U–Pb dating, and Sr–Nd isotopic analyses to assess its homogeneity of chemical composition and suitability as a reference material for microbeam U–Pb dating and Nd isotope analyses. Through comprehensive analyses, we show that the MAP-3 apatite is free of mineral inclusions and is uniform at the level of analytical precision of major- and trace element, U–Pb isotopic, and Nd isotopic ratios despite compositional zones from CL images. The MAP-3 apatite has ID-TIMS determined mean isotopic ratio values of 0.13222 ± 0.00016 for 206Pb/238U, 1.2084 ± 0.0030 for 207Pb/235U, and 0.0663 ± 0.0001 for 207Pb/206Pb and the weighted mean 206Pb/238U ages of 800.5 ± 0.9 Ma (2 s, MSWD = 1.5, n = 11). The 143Nd/144Nd isotopic results determined by (ID)-TIMS are 0.511248 ± 0.000006 (2 s, MSWD = 4.2, n = 11) with moderate Nd contents of ∼1532 ppm. U–Pb age and Nd isotopic compositions obtained by LA-(Q, SF-SC, MC)-ICPMS analysis are reproducible and agree with the values of TIMS, which indicates that MAP-3 apatite has the potential to be a primary reference material for microbeam determination of U–Pb ages and Nd isotope analyses. To validate the effectiveness of the potential, we dated some apatite reference materials of known age and two geological apatites. The results demonstrated the high-quality U–Pb dating reference materials used with MAP-3 apatite. [ABSTRACT FROM AUTHOR]

We report the laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) 176Hf/177Hf ratios for cassiterite of a known age and demonstrate that the 176Hf/177Hf ratios can be measured accurately and reproducibly with adequate precision for cassiterite with Hf contents around 100 μg g−1. Although cassiterite only has minor rare earth elements (REEs), corrections for Yb and Lu interferences are required as they may affect the determination of the 176Hf/177Hf ratios. Among the investigated samples, Rond-A has a homogeneous Hf isotopic composition. We recommend cassiterite sample Rond-A as a primary reference material for in situ Hf isotope analysis. The Kard sample has a homogeneous Hf isotopic composition and is suitable as a primary reference material once its Hf isotopic composition has been confirmed by solution-based MC-ICP-MS. Samples BB#7, 19MP, and 19GX showed minor variations in their Hf isotopic compositions and, therefore, can only be used as secondary reference materials. [ABSTRACT FROM AUTHOR]

Nowadays, in situ Fe isotopic analysis is facing a dilemma that the conventional reference material of IRMM-014 for isotope ratio normalization is commercially unavailable and is unable to meet the needs of laboratories. In this study, the other Fe metal (IRMM-524A), instead of the nearly exhausted IRMM-014, has been systematically checked to be a potential reference material for the Fe isotopic analysis by femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (fs LA-MC-ICP-MS). A total of 136 analyses on IRMM-524A were directly calibrated against IRMM-014 using fs LA-MC-ICP-MS during eight analytical sessions. The result shows that the IRMM-524A Fe metal is relatively homogeneous, with average values of 0.01 ± 0.13‰ and −0.02 ± 0.19‰ (2SD, n = 136) for δ56Fe and δ57Fe, respectively, which are identical to the published values obtained by solution nebulizer (SN)-MC-ICP-MS within analytical uncertainties. Fe isotopic compositions of two in-house standards (Balmat pyrite, PZH12-24 ilmenite) and four natural samples (NKAu01 pyrite, PZH12-16 ilmenite, PZH12-18 ilmenite, and Moosilauke ilmenite) measured by fs LA-MC-ICP-MS relative to IRMM-524A or IRMM-014 are identical within analytical uncertainties. In addition, five of the samples (Balmat pyrite, PZH12-24 ilmenite, NKAu01 pyrite, PZH12-16 ilmenite, and PZH12-18 ilmenite) have homogeneous Fe isotopic compositions and yield an external reproducibility of 0.12‰ to 0.16‰ for δ56Fe values for different sections within three years. Thus, the IRMM-524A Fe metal and other five samples can be used as reference material and secondary standards for quality assurance for non-matrix-matched Fe isotopic analysis of pyrite and ilmenite by fs LA-MC-ICP-MS. [ABSTRACT FROM AUTHOR]

High-quality Sr isotope data are critically dependent on the quality of reference materials that are used for instrumental calibration and data monitoring during LA-MC-ICP-MS analysis. A suite of natural plagioclase samples (BDL-1, BDL-2 and BDL-3) from the Badaling intrusive complex, Beijing were investigated here to test their suitability as a plagioclase Sr isotope reference material. Major and trace element analyses by EPMA and LA-ICP-MS showed that plagioclase crystals separated from two troctolites (BDL-1 and BDL-3) and one gabbro (BDL-2) were all characterized by extremely low Rb/Sr ratios (0.00012–0.00047), and low heavy rare earth elements (HREEs) and high Sr contents (2377–2836 μg g−1). A total of 200 LA-MC-ICP-MS analyses for plagioclases BDL-1, BDL-2 and BDL-3 showed consistent and homogeneous Sr isotopic compositions with an average 87Sr/86Sr ratio of 0.70535 ± 0.00007 (2SD), which was in good agreement with solution-based data determined by TIMS or SN-MC-ICP-MS (0.70533 ± 0.00004; 2SD, n = 12), thus suggesting that BDL plagioclase can be used as a potential reference material for microbeam Sr isotopic analysis. Compared to the other available plagioclase Sr isotopic reference materials, the large quantities, long-term availability, high Sr content and extremely low isobaric interference (Rb, Er and Yb) of BDL plagioclase make it especially suitable for instrumental calibration and to adjust for inter-laboratory bias of the measured 87Sr/86Sr ratios. [ABSTRACT FROM AUTHOR]

A new natural zircon reference material SA01 is introduced for U‐Pb geochronology as well as O and Hf isotope geochemistry by microbeam techniques. The zircon megacryst is homogeneous with respect to U‐Pb, O and Hf isotopes based on a large number of measurements by laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) and secondary ion mass spectrometry (SIMS). Chemical abrasion isotope dilution thermal ionisation mass spectrometry (CA‐ID‐TIMS) U‐Pb isotopic analyses produced a mean 206Pb/238U age of 535.08 ± 0.32 Ma (2s, n = 10). Results of SIMS and LA‐ICP‐MS analyses on individual shards are consistent with the TIMS ages within uncertainty. The δ18O value determined by laser fluorination is 6.16 ± 0.26‰ (2s, n = 14), and the mean 176Hf/177Hf ratio determined by solution MC‐ICP‐MS is 0.282293 ± 0.000007 (2s, n = 30), which are in good agreement with the statistical mean of microbeam analyses. The megacryst is characterised by significant localised variations in Th/U ratio (0.328–4.269) and Li isotopic ratio (−5.5 to +7.9‰); the latter makes it unsuitable as a lithium isotope reference material. [ABSTRACT FROM AUTHOR]

The suitability of 13 Chinese silicate rock certified reference materials for Sr and Nd isotope analyses was investigated. To indicate their homogeneity and to provide information values, we report Sr and Nd isotopic data and Rb, Sr, Sm and Nd concentrations for reference materials GBW07 103–105, 109–113 and 121–125 spanning a broad compositional range. Test portions were spiked with tracers enriched in 87Rb–84Sr and 149Sm–145,146,150Nd and digested using HF, HNO 3 , and HClO 4 acid-dissolution procedures. Chemical purification involved cation-exchange and HEHEHP or Ln resins. Analyses involved different instruments at four laboratories, including thermal ionisation mass spectrometry (TIMS) and multicollector–inductively coupled plasma–mass spectrometry (MC–ICP–MS). This study provides a comprehensive report of the Rb–Sr and Sm–Nd isotopic compositions of the reference materials, and the results indicate that the materials are comparable to those of well-characterised and widely utilized reference materials from the US Geological Survey and the Geological Survey of Japan. This is the first report of the Sr and Nd isotopic composition of standards GBW07111, GBW07112, GBW07121, GBW07122, GBW07123, GBW07124 and GBW07125. Our results are useful for quality control and assurance between laboratories and provide a robust reference-rock dataset for future studies involving classical Sr and Nd isotopic geochemistry. [Display omitted] • Rb, Sr, Sm, Nd contents, Sr and Nd isotopic ratios of 13 Chinese rock reference materials are reported for the first time using ID-TIMS or ID-MC-ICP-MS. • The reference materials span a broad compositional range. • Results indicate that they are of comparable quality to the well characterized and widely utilized USGS and GSJ rock reference materials. [ABSTRACT FROM AUTHOR]

This study investigated the influences of plasma condition, concentration effect, ablation position and on-line addition of an aqueous Ni standard for non-matrix-matched Fe isotopic analysis by femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (fs LA–MC–ICP–MS). Deviations up to ~0.7‰ in δ56Fe values caused by non-matrix-matched analyses were difficult to eliminate under dry plasma condition even with fs-LA. However, the nebulized water after the ablation cell efficiently reduces or eliminates the matrix-dependent fractionation of Fe isotopes without reducing signal intensity. Furthermore, concentration- and position-dependent fractionation of Fe isotopes was not observed under wet plasma condition. For instrumental mass bias correction, the standard–sample bracketing (SSB) method and SSB with Ni doping (SSB + Ni) were performed in the presence of nebulized water with fs LA–MC–ICP–MS. Results indicate that both the SSB and SSB + Ni methods are sufficient to correct for instrumental mass bias under wet plasma condition, with the SSB + Ni method being more effective in calibrating short-term fluctuations in mass bias with improved external reproducibility of ~0.15‰ (2SD) for δ56Fe values. Compared to SN–MC–ICP–MS, deteriorated precision offered by fs LA–MC–ICP–MS may represent a major limitation for some applications relying upon precise Fe isotope ratio measurements. This approach for non-matrix-matched analysis of Fe isotopes by fs LA–MC–ICP–MS under wet plasma condition combined with the SSB + Ni method allows for more flexibility in tracing detailed geological processes with large Fe isotope fractionation of a wide range of solids. Relatively precise and accurate Fe isotopic compositions of potential reference materials of Balmat pyrite (δ56Fe = −1.32 ± 0.12‰, δ57Fe = −1.91 ± 0.20‰; 2SD, n = 166) and PZH12–24 ilmenite (δ56Fe = −0.38 ± 0.15‰, δ57Fe = −0.57 ± 0.23‰; 2SD, n = 134) were obtained using this analytical protocol, consistent with reference values obtained by solution nebulization (SN)–MC–ICP–MS within analytical uncertainties (Balmat pyrite: δ56Fe = −1.30 ± 0.04‰, δ57Fe = −1.94 ± 0.07‰, 2SD, n = 3; PZH12–24 ilmenite: δ56Fe = −0.38 ± 0.06‰, δ57Fe = −0.55 ± 0.07‰, 2SD, n = 6). [Display omitted] • A strategy of non-matrix-matched Fe isotopic analysis by fs LA–MC–ICP–MS is provided. • Evaluation of plasma condition, concentration and position effect are discussed. • A comparison of SSB and SSB + Ni for mass bias correction is discussed. • Fe isotopic compositions of potential standards of pyrite and ilmenite are presented. [ABSTRACT FROM AUTHOR]