scholarly journals Further Characterization of the RW-1 Monazite: A New Working Reference Material for Oxygen and Neodymium Isotopic Microanalysis

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 583 ◽  
Author(s):  
Wu ◽  
Li ◽  
Ling ◽  
Yang ◽  
Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Reference Material ◽  
Inductively Coupled Plasma ◽  
Secondary Ion Mass Spectrometry ◽  
Hydrothermal Activity ◽  
Ionization Mass ◽  
Nd Isotopes ◽  
Inductively Coupled ◽  
The Matrix ◽  
Plasma Mass Spectrometry

The oxygen (O) and neodymium (Nd) isotopic composition of monazite provides an ideal tracer of metamorphism and hydrothermal activity. Calibration of the matrix effect and monitoring of the external precision of monazite O–Nd isotopes with microbeam techniques, such as secondary ion mass spectrometry (SIMS) and laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICPMS), require well-characterized natural monazite standards for precise microbeam measurements. However, the limited number of standards available is impeding the application of monazite O–Nd isotopes. Here, we report on the RW-1 monazite as a potential new working reference material for microbeam analysis of O–Nd isotopes. Microbeam measurements by electron probe microanalysis (EPMA), SIMS, and LA-MC-ICPMS at 10–24 µm scales have confirmed that it is homogeneous in both elemental and O–Nd isotopic compositions. SIMS measurements yield δ18O values consistent, within errors, with those obtained by laser fluorination techniques. Precise analyses of Nd isotope by thermal ionization mass spectrometry (TIMS) are consistent with mean results of LA-MC-ICPMS analyses. We recommend δ18O = 6.30‰ ± 0.16‰ (2SD) and 143Nd/144Nd = 0.512282 ± 0.000011 (2SD) as being the reference values for the RW-1 monazite.

scholarly journals Isotope analysis of highly enriched “silicon-28” by high-resolution inductively coupled plasma mass spectrometry using an internal standard

2021 ◽  
Vol 25 (2) ◽  
pp. 98-109
Author(s):  
P. A. Otopkova ◽  
◽  
A. M. Potapov ◽  
A. I. Suchkov ◽  
A. D. Bulanov ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Matrix Element ◽  
High Resolution ◽  
Inductively Coupled Plasma ◽  
Internal Standard ◽  
Isotopic Analysis ◽  
Random Component ◽  
Inductively Coupled ◽  
The Matrix ◽  
Plasma Mass Spectrometry

In order to study the isotopic effects in semiconductor materials, single crystals of high chemical and isotopic purity are required. The reliability of the obtained data on the magnitude and the direction of isotopic shifts depends on the accuracy of determining the concentration of all stable isotopes. In the isotopic analysis of enriched “silicon-28” with a high degree of enrichment (> 99.99%), it is necessary to determine the impurities of 29Si and 30Si isotopes at the level of 10-3 ¸ 10-5 at. %. At this concentration level, these isotopes can be considered as impurities. It is difficult to achieve high measurement accuracy with simultaneous registration of the main and “impurity” isotopes in such a wide range of concentrations. The registration of analytical signals of silicon isotopes must be carried out in the solutions with different matrix concentrations. The use of the solutions with the high concentration of the matrix element requires the introduction of corrections for matrix noise and the drift of the instrument sensitivity during the measurement. It is possible to reduce the influence of the irreversible non-spectral interference and sensitivity drift by using the method of internal standardization. The inconsistency of the literature data on the selection criteria for the internal standard required studying the behavior of the signals of the “candidates for the internal standard” for the ELEMENT 2 single-collector high-resolution inductively coupled plasma mass spectrometer on the matrix element concentration and the nature of the solvent, as well as on the solution nebulizing time. Accounting for the irreversible non-spectral matrix noise and instrumental drift in isotopic analysis of enriched “silicon-28” and initial 28SiF4 by inductively coupled plasma mass spectrometry had allowed us to reduce by 3-5 times the random component and by more than an order of magnitude the systematic component of the measurement error in comparison with the external standard method. This made it possible to carry out, with sufficient accuracy, the operational control of the isotopic composition of enriched “silicon-28”, both in the form of silicon tetrafluoride and polycrystalline silicon obtained from it, using a single serial device in the range of isotopic concentrations 0.0001–99.999%.

Contact Metamorphic and Metasomatic Processes at the Kharaelakh Intrusion, Oktyabrsk Deposit, Norilsk-Talnakh Ore District: Application of LA-ICP-MS Dating of Perovskite, Apatite, Garnet, and Titanite

2020 ◽  
Vol 115 (6) ◽  
pp. 1213-1226 ◽  
Author(s):  
Alexander E. Marfin ◽  
Alexei V. Ivanov ◽  
Vadim S. Kamenetsky ◽  
Adam Abersteiner ◽  
Tamara Yu. Yakich ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Metamorphic Rocks ◽  
Complete Agreement ◽  
Ionization Mass ◽  
Pb Isotope ◽  
Inductively Coupled ◽  
Prolonged Duration ◽  
Plasma Mass Spectrometry ◽  
Ore District

Abstract The Norilsk-Talnakh ore district in the northwestern Siberian platform contains globally unique reserves of Cu-Ni-sulfides with Pt and, especially, Pd. The Oktyabrsk deposit, which is one of the largest in the district, is spatially and genetically associated with the Kharaelakh mafic-ultramafic intrusion and its exceptionally large metamorphic and metasomatic aureoles. In this study, we employed in situ laser ablation-inductively coupled plasma-mass spectrometry U-Pb isotope dating of apatite, titanite, garnet, and perovskite that cocrystallize with disseminated sulfides within the aureole of metasomatic and contact metamorphic rocks. The calculated isotopic ages for apatite (257.3 ± 4.5 and 248.9 ± 5.1 Ma), titanite (248.6 ± 6.8 and 249.1 ± 2.9 Ma), garnet (260.0 ± 11.0 Ma), and perovskite (247.3 ± 8.2 Ma), though with large uncertainties, indicate that sulfide mineralization within metasomatic and contact-metamorphic rocks is coeval with the emplacement of the Kharaelakh intrusion. These isotopic dates are in complete agreement with the published isotope dilution-thermal ionization mass spectrometry U-Pb zircon ages for the Norilsk intrusions and, at the same time, notably older than available Re-Os isochron ages of sulfides. The latter ages have been long interpreted as evidence for a prolonged duration of magmatic ore-forming processes; however, our data narrow their life span. Trace elements in titanite and garnet allow distinguishing late- and postmagmatic grains, which show indistinguishable U-Pb isotope ages.

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