Off‐Mount Calibration and One New Potential Pyrrhotite Reference Material for Sulfur Isotope Measurement by Secondary Ion Mass Spectrometry

• Published in: Geostandards and Geoanalytical Research
• Main Authors: Li, Rucao, Xia, Xiaoping, Yang, Shenghong, Chen, Huayong, Yang, Qing
• Other Authors: National Key R & D Program of China, Guangzhou Municipal Government, Chinese National Basic Research 973-Program
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2018
• Subjects: Northern Finland
• Online Access: http://dx.doi.org/10.1111/ggr.12244; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fggr.12244; https://onlinelibrary.wiley.com/doi/pdf/10.1111/ggr.12244; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/ggr.12244

Sulfur isotope measurements in three sulfide (two pyrite and one pyrrhotite) samples on two epoxy mounts showed that the mount‐to‐mount variation of raw δ 34 S values was negligible when secondary ion mass spectrometry ( SIMS ) analytical settings remained stable. In consequence, an off‐mount calibration procedure for SIMS sulfur isotope analysis was applied in this study. YP 136 is a pyrrhotite sample collected from northern Finland. Examination of thin sections with a polarising microscope, backscattered electron image analyses and wavelength dispersive spectrometry mapping showed that the sample grains display no internal growth or other zoning. A total of 318 sulfur isotope (spot) measurements conducted on more than 100 randomly selected grains yielded highly consistent sulfur isotope ratios. The repeatability of all the analytical results of 34 S/ 32 S was 0.3‰ (2 s , n = 318), which is the same as that of the well‐characterised pyrite reference materials PPP ‐1 and UWP y‐1. Its δ 34 S value determined by gas mass spectrometry was 1.5 ± 0.1‰ (2 s , n = 11), which agrees with the SIMS data (1.5 ± 0.3‰, 2 s ) calibrated by pyrrhotite reference material Po‐10. Therefore, YP 136 pyrrhotite is considered a candidate reference material for in situ sulfur isotope determination.