Simultaneous determination of sulfur isotopes and trace elements in pyrite with a NanoSIMS 50L. Issue 47 (22nd November 2017)

• Record Type: Journal Article
• Authors: Zhang, Jianchao; Lin, Yangting; Yan, Jun; Li, Jinxiang; Yang, Wei
• Is Part Of: Analytical methods. Volume 9:Issue 47(2017)
• Page Start: 6653
• Page End: 6661
• Publication Date: 2017-11-22
• Subjects: Chemistry, Analytic -- Periodicals; Analytical biochemistry -- Periodicals; Chemical laboratories -- Standards -- Periodicals; 543.1905
• DOI: 10.1039/c7ay01440f
• Languages: English
• ISSNs: 1759-9660

Abstract

Abstract : In this paper, we established simultaneous and quantitative analyses of 34 S/ 32 S ratios and trace element contents of pyrite using nanometer-scale secondary ion mass spectrometry (NanoSIMS). Abstract : Pyrite is common sulfide mineral involved in the formation of various ores and hydrothermal and biogenetic activities, and its S isotopic ratios and trace element contents and their spatial distribution have been recorded in the processes of these events. We established simultaneous analyses of 34 S/ 32 S ratios and trace element contents of pyrite using nanometer-scale secondary ion mass spectrometry (NanoSIMS). Firstly, the images of S ( 34 S − ), As ( 75 As − ), Se ( 80 Se − ), Cu ( 63 Cu 32 S − ), Au ( 197 Au − ) and Pb ( 208 Pb 32 S − ) of pyrite were acquired by rastering areas ranging from 20 × 20 μm 2 to 40 × 40 μm 2 using a Cs + beam of 7–10 pA with a diameter of ∼250 nm. Then, the 34 S/ 32 S ratios ( 32 S − measured by using a Faraday cup and 34 S − measured by using an electron multiplier) and the concentrations of these trace elements of the individual layers of the zoned pyrite grains were simultaneously measured in spot analysis mode, by rastering the same current over an area of 2 × 2 μm 2 . The 34 S/ 32 S ratios were calibrated for matrix effects with pyrite standard Balmat or Py1117, and the external reproducibility (1SD) is <0.5‰. The concentrations of trace elements were calibrated using the relative sensitivity factors (RSFs) of As, Se, Cu, Au and Pb, which were determined from pyrite grains with zoning layers. The determined RSFs of As, CuS, Au and PbS are 4.43 ± 0.28, 0.36 ± 0.04, 0.18 ± 0.03 and 38.0 ± 15.1, respectively. Pyrite from Lannigou Carlin type gold deposits was analyzed as an example, and the results revealed three main episodes of its formation, with each superposed by micron-width oscillation zonings of trace elements. This method has important potential applications in isotopic and elemental investigation of thin layers of pyrite and other sulfides.