A nebula setting as the origin for bulk chondrule Fe isotope variations in CV chondrites

Hezel, Dominik C.; Needham, Andrew; Armytage, Ros; Georg, R. Bastian; Abel, Richard; Kurahashi, E.; Coles, Barry J.; Rehkämper, Mark; Russell, S. S.

doi:10.1016/j.epsl.2010.05.029

Cited by 50 publications

(54 citation statements)

References 69 publications

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“…H2O nebulisation) were <30 mV, <2 mV and <1 mV on 28 Si, 29 Si and 30 Si, respectively. The individual contributions to the total observed background signals originate from electronic noise of the detection system, impurities in gas (He, Ar) and H 2 O-nebulisation as well as from other solid parts of the sample introduction system (e.g., tubings, torch, cones), but were not quantified separately.…”

Section: Mc-icp-msmentioning

confidence: 99%

“…Measurements were done in dynamic mode (magnet jump), alternating between Si and Mg isotopes for 30 cycles á 4 seconds integrations time. Based on repeat sample dissolutions and measurements, and comparison to published data on reference materials ( Table 2) analytical uncertainties of solution MC-ICP-MS data are estimated to be ± 0.11‰ (2SD) and ± 0.09‰ (2SD) on  30 Si and  29 Si, respectively. Si isotope ratios are reported in the delta notation for the 30 Si/ 28 Si ( 30 Si) and 29 Si/ 28 Si ( 29 Si) isotope ratios relative to NBS-28.…”

Section: Mass Spectrometrymentioning

confidence: 99%

“…Unfavourably high laser fluencies of 20 J/cm² (b, e) cause erratic ablation behaviour and deteriorating isotope ratio precision. During single spot analyses (c, f) the precision in the isotope ratio is limited by counting statistics due fast decreasing and overall lower 30 Si signal intensities. Intensities are decreasing as the laser ablation pit is becoming deeper and hence effective aerosol transport is reduced.…”

Section: Mass Spectrometrymentioning

confidence: 99%

“…These represent the optimum conditions based on systematic tests. Gas flows were optimised on a daily bases but 30 Si/ 28 Si ratios and their statistics given as 2 standard deviation (2SD ±0.28 ‰, dashed lines) and 2 standard error (2SE ±0.04 ‰, stippled lines) of the mean. Unfavourably high laser fluencies of 20 J/cm² (b, e) cause erratic ablation behaviour and deteriorating isotope ratio precision.…”

Section: Mass Spectrometrymentioning

confidence: 99%

“…Moveable Faraday detectors with 10 11 Ω amplifiers were precisely positioned to obtain interference-free flat-top peak shoulders for simultaneous detection of all three stable Si isotopes. Faraday cups L2, C, and H2 were used for simultaneous measurements of 28 Si, 29 Si, and 30 Si, respectively. With this cup configuration 27 Al (L4) can be detected simultaneously, which can be used for Al concentration measurements.…”

Section: Mass Spectrometrymentioning

confidence: 99%

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Testing the limits of micro-scale analyses of Si stable isotopes by femtosecond laser ablation multicollector inductively coupled plasma mass spectrometry with application to rock weathering

Schuessler

Blanckenburg

2014

Spectrochimica Acta Part B: Atomic Spectroscopy

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Abstract. An analytical protocol for accurate in-situ Si stable isotope analysis has been established on a new second-generation custom-built femtosecond laser ablation system. The laser was coupled to a multicollector inductively coupled plasma mass spectrometer (fsLA-MC-ICP-MS). We investigated the influence of laser parameters such as spot size, laser focussing, energy density and repetition rate, and ICP-MS operating conditions such as ICP mass load, spectral and nonspectral matrix effects, signal intensities, and data processing on precision and accuracy of Si isotope ratios. We found that stable and reproducible ICP conditions were obtained by using He as aerosol carrier gas mixed with Ar/H2O before entering the plasma. Precise  29 Si and  30 Si values (better than ±0.23‰, 2SD) can be obtained if the area ablated is at least 50 x 50 µm; or, alternatively, for the analysis of geometric features down to the width of the laser spot (about 20 µm) if an equivalent area is covered. Larger areas can be analysed by rastering the laser beam, whereas small single spot analyses reduce the attainable precision of  30 Si to ca. ±0.6 ‰, 2SD, for <30 µm diameter spots. It was found that focussing the laser beam beneath the sample surface with energy densities between 1 and 3.8 J/cm² yields optimal analytical conditions for all materials investigated here. Using pure quartz (NIST 8546 aka. NBS-28) as measurement standard for calibration (standard-sample-bracketing) did result in accurate and precise data of international reference materials and samples covering a wide range in chemical compositions (Si single crystal IRMM-017, basaltic glasses KL2-G, BHVO-2G and BHVO-2, andesitic glass ML3B-G, rhyolitic glass ATHO-G, diopside glass JER, soda-lime glasses NIST SRM 612 and 610, San Carlos olivine). No composition-dependent matrix effect was discernible within uncertainties of the method. The method was applied to investigate the Si isotope signature of rock weathering at the micro-scale in a corestone sampled from a highly weathered roadcut profile in the tropical Highlands of Sri Lanka. The results show that secondary weathering products accumulated in cracks and grain boundaries are isotopically lighter than their unweathered plagioclase host, consistent with isotopically heavy dissolved Si found in rivers.

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Section: Mc-icp-msmentioning

confidence: 99%

Section: Mass Spectrometrymentioning

confidence: 99%

Section: Mass Spectrometrymentioning

confidence: 99%

Section: Mass Spectrometrymentioning

confidence: 99%

Section: Mass Spectrometrymentioning

confidence: 99%

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Testing the limits of micro-scale analyses of Si stable isotopes by femtosecond laser ablation multicollector inductively coupled plasma mass spectrometry with application to rock weathering

Schuessler

Blanckenburg

2014

Spectrochimica Acta Part B: Atomic Spectroscopy

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High‐spatial‐resolution measurements of iron isotopes in pyrites by secondary ion mass spectrometry using the new Hyperion‐II radio‐frequency plasma source

Decraene

Marin‐Carbonne

Bouvier

et al. 2020

Rapid Comm Mass Spectrometry

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Rationale: Iron isotopic signatures in pyrites are considered as a good proxy to reconstruct paleoenvironmental and local redox conditions. However, the investigation of micro-pyrites less than 20µm size has been limited so far by analytical techniques. The development of the new brighter radio-frequency plasma ion source (Hyperion-II source) enhances the spatial resolution by increasing the beam density 10 times compared to the Duoplasmatron source.Methods: Here we present high spatial resolution measurements of iron isotopes in pyrites using a 3nA-3µm primary 16 Obeam on two ion microprobes Cameca IMS 1280-HR2 at CRPG-IPNT (France) and at SwissSIMS (Switzerland) equipped with Hyperion sources. We tested analytical effects, such as topography and crystal orientation that could induce analytical biases perceptible through variations of the Instrumental Mass Fractionation (IMF). Results:The δ 56 Fe reproducibility for the Balmat pyrite standard is ±0.25‰ (2SD, standard deviation) and the typical individual internal error is ±0.10‰ (2SE, standard error). The sensitivity on 56 Fe + was 1.2x10 7 cps/nA/ppm or better. Tests on Balmat pyrites revealed that neither the crystal orientation nor channeling effects seem to significantly influence the IMF.Different pyrite standards (Balmat and SpainCR) were used to test the accuracy of the measurements. Indium mounts must be carefully prepared with sample topography < 2µm, which was checked using an interferometric microscope. Such a topography is negligible for introducing change in the IMF. This new source increases the spatial resolution while maintaining the high precision of analyses and the overall stability of the measurements compared to the Duoplasmatron source. Conclusions:We developed a reliable method to perform accurate and high-resolution measurements of micrometric pyrites. The investigation of sedimentary micro-pyrites will improve our understanding of the processes and environmental conditions during pyrite precipitation, including contribution of primary (microbial activities or abiotic reactions) and secondary (diagenesis and/or hydrothermal fluid circulation) signatures.

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High-Temperature Fe Isotope Geochemistry

Beard

Weyer

2020

Iron Geochemistry: An Isotopic Perspective

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A nebula setting as the origin for bulk chondrule Fe isotope variations in CV chondrites

Cited by 50 publications

References 69 publications

Testing the limits of micro-scale analyses of Si stable isotopes by femtosecond laser ablation multicollector inductively coupled plasma mass spectrometry with application to rock weathering

Testing the limits of micro-scale analyses of Si stable isotopes by femtosecond laser ablation multicollector inductively coupled plasma mass spectrometry with application to rock weathering

High‐spatial‐resolution measurements of iron isotopes in pyrites by secondary ion mass spectrometry using the new Hyperion‐II radio‐frequency plasma source

High-Temperature Fe Isotope Geochemistry

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