Laser ablation inductively coupled plasma mass spectrometry for direct analysis of the spatial distribution of trace elements in metallurgical-grade silicon

The spatial distribution and concentration of impurities in metallurgical-grade silicon (MG-Si) samples (97-99% w/w Si) were investigated by use of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The spatial resolution (120μm) and low limits of detection (mg kg−1) for quality assurance of such materials were studied in detail. The volume-dependent precision and accuracy of non-matrix-matched calibration for quantification of minor elements, using NIST SRM 610 (silicate standard), indicates that LA-ICP-MS is well suited to rapid process control of such materials. Quantitative results from LA-ICP-MS were compared with previously reported literature data obtained by use of ICP-OES and rf-GD-OES. In particular, the distribution of element impurities and their relationship to their different segregation coefficients in silicon is demonstrate

MPI-DING reference glasses for in situ microanalysis: New reference values for element concentrations and isotope ratios

We present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, BM90/21-G, T1-G, and ATHO-G. Different analytical methods were used to obtain a large spectrum of major and trace element data, in particular, EPMA, SIMS, LA-ICPMS, and isotope dilution by TIMS and ICPMS. Altogether, more than 60 qualified geochemical laboratories worldwide contributed to the analyses, allowing us to present new reference and information values and their uncertainties (at 95% confidence level) for up to 74 elements. We complied with the recommendations for the certification of geological reference materials by the International Association of Geoanalysts (IAG). The reference values were derived from the results of 16 independent techniques, including definitive (isotope dilution) and comparative bulk (e.g., INAA, ICPMS, SSMS) and microanalytical (e.g., LA-ICPMS, SIMS, EPMA) methods. Agreement between two or more independent methods and the use of definitive methods provided traceability to the fullest extent possible. We also present new and recently published data for the isotopic compositions of H, B, Li, O, Ca, Sr, Nd, Hf, and Pb. The results were mainly obtained by high-precision bulk techniques, such as TIMS and MC-ICPMS. In addition, LA-ICPMS and SIMS isotope data of B, Li, and Pb are presented. Copyright 2006 by the American Geophysical Union

MPI-Ding reference glasses for in situ microanalysis: New reference values for element concentrations and isotope ratios

We present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, BM90/21-G, T1-G, and ATHO-G. Different analytical methods were used to obtain a large spectrum of major and trace element data, in particular, EPMA, SIMS, LA-ICPMS, and isotope dilution by TIMS and ICPMS. Altogether, more than 60 qualified geochemical laboratories worldwide contributed to the analyses, allowing us to present new reference and information values and their uncertainties (at 95% confidence level) for up to 74 elements. We complied with the recommendations for the certification of geological reference materials by the International Association of Geoanalysts (IAG). The reference values were derived from the results of 16 independent techniques, including definitive (isotope dilution) and comparative bulk (e.g., INAA, ICPMS, SSMS) and microanalytical (e.g., LA-ICPMS, SIMS, EPMA) methods. Agreement between two or more independent methods and the use of definitive methods provided traceability to the fullest extent possible. We also present new and recently published data for the isotopic compositions of H, B, Li, O, Ca, Sr, Nd, Hf, and Pb. The results were mainly obtained by high-precision bulk techniques, such as TIMS and MC-ICPMS. In addition, LA-ICPMS and SIMS isotope data of B, Li, and Pb are presented

Laser ablation inductively coupled plasma mass spectrometry for direct analysis of the spatial distribution of trace elements in metallurgical-grade silicon

ISSN:1618-2650ISSN:1618-264

Iron-60 heterogeneity and incomplete isotope mixing in the early solar system

International audienceShort-lived radionuclides (e.g., (26)Al, (53)Mn, (60)Fe, (182)Hf) are widely used to refine the chronology of the early solar system. They provide chronological information, however, only if they were homogeneously distributed in the source region of the objects under scrutiny at the time of their formation. With the high level of precision now achieved on isotopic measurements, very short time intervals can in principle be resolved and a precise evaluation of the initial homogeneity degree becomes increasingly crucial. High-precision nickel isotope data for differentiated meteorites (angrites, ureilites) and chondritic (CB) components allow us to test the initial distribution of radioactive (60)Fe and stable Ni isotopes. Although these meteorites appear to have formed nearly contemporaneously, they yield variable initial (60)Fe/(56)Fe ratios. Besides, the CB metal nodules and ureilite silicates show nucleosynthetic anomalies. The new data presented here do not confirm the recently inferred late injection of (60)Fe into the protoplanetary disk. Instead, live (60)Fe was present, but heterogeneously distributed, from the start of the solar system, revealing an incomplete mixing of material from various nucleosynthetic sources and restricting the use of the (60)Fe-(60)Ni system as a chronometer

Natal homing in a marine fish metapopulation

Identifying natal origins of marine fishes is challenging because of difficulties in conducting mark-recapture studies in marine systems. We used natural geochemical signatures in otoliths (ear bones) to determine natal sources in weakfish ( Cynoscion regalis ), an estuarine-spawning marine fish, in eastern North America. Spawning site fidelity ranged from 60 to 81%, comparable to estimates of natal homing in birds and anadromous fishes. These data were in contrast to genetic analyses of population structure in weakfish. Our findings highlight the need for consideration of spatial processes in fisheries models and have implications for the design of marine reserves in coastal regions. </jats:p

Rates of magma differentiation and emplacement in a ballooning pluton recorded by U-Pb TIMS-TEA, Adamello batholith, Italy

Geochemical, structural, field, and geochronological data have been used to arrive at very different models for the construction of upper crustal batholiths. Models for pulsed intrusion of small magma batches over long timescales (>1 Ma) versus transfer of larger magma bodies on shorter timescales predict a different thermal, metamorphic, and rheological state of the crust, highlighting the importance of robust time constraints. This study focuses on a well-characterized upper crustal intrusion, the 15 km2 Lago della Vacca complex (LVC), Adamello batholith, N. Italy. Previous studies used structural and petrologic data to argue that the LVC was emplaced through pulsed magma injection and in situ expansion (or, ballooning) of a short lived (∼ 105 yr) magma chamber. We test this model using a dense sampling strategy and high-precision ID-TIMS U-Pb geochronology of zircon and titanite combined with hafnium isotope and trace element analyses of the same volume of dated mineral (U-Pb TIMS-TEA). These data show that the marginal mafic pulses of magma crystallized zircon with primitive Hf isotopes and negligible Eu anomalies during fractional crystallization and ascent through the crust on 10-30 ka timescales. Subsequent, more felsic pulses yield individual zircon dates spanning as much as 200 ka within single handsamples and restrict the total construction time of the LVC to <300 ka. Rim to core solidification of the LVC, as recorded by titanite U-Pb thermochronology, occurred in ≥300 ka. U-Pb TIMS-TEA data from these complicated zircon populations limit the sources of antecrystic zircon, constrain AFC processes within host magmas, and illustrate the difficulty in interpreting zircon dates as magma emplacement ages. These data are supportive of growth of the LVC by a pulsed ballooning-type process over ∼300 ka, with the restriction that the rims of the LVC had solidified prior to the center-most injection, providing important constraints for thermomechanial models and strain analysis of the LVC and other balloon-like intrusions

60Fe-60Ni systematics in the eucrite parent body: A case study of Bouvante and Juvinas

International audienceEucrites are basaltic meteorites that cooled rapidly but are in many instances thermally metamorphosed and impact brecciated. The exact timing of these events remains unclear. In this study, Ni isotopic compositions and Fe/Ni elemental ratios are presented for two non-cumulate eucrites, Bouvante and Juvinas, including mineral separates from the latter. The samples are characterized by variable, well-resolved (60)Ni-excesses consistent with the former presence of live (60)Fe (t(1/2) = 2.62 Ma) at the time of eucrite crystallization. A significant fraction of Ni with a terrestrial-like composition appears to be surface correlated. This Ni may be the product of terrestrial contamination or was introduced by a chondritic impactor during brecciation. Altogether, the data provide evidence for a complex and probably multi-stage history of Fe and/or Ni redistribution, which impedes the interpretation of the chronological dat