Supplementary tables for olivine.xlsx

Olivine is a key component of mafic-ultramafic and metamorphic rocks. Oxygen isotopic composition of olivine has been widely used to decipher mantle processes, igneous differentiation, and fluid-rock interaction in metamorphic systems. Accurate in situ oxygen isotopic analysis of olivine by secondary ion mass spectrometry (SIMS) requires matrix-matched reference materials to correct instrumental mass fractionation and monitor analytical accuracy. In this study, we report three natural olivine reference materials, AOL, POL and NOL, for SIMS oxygen isotopic analysis. These samples exhibit homogeneous oxygen isotopic compositions, with a two-standard deviation of 0.33‰ (N = 105), 0.37‰ (N =105), and 0.33‰ (N = 105), respectively. The recommended δ¹⁸O values, determined by laser fluorination isotope ratio mass spectrometry, are 5.52 ± 0.13‰ for AOL, 5.64 ± 0.06‰ for POL, and 5.82 ± 0.09‰ for NOL (all ± 1SD, N = 5). Combined with previous reported olivine standards, our results confirm that no significant matrix effects were observed within the forsterite (Fo) content range of Fo₉₁ to Fo₉₇, supporting wide usage of AOL, POL, and NOL as reference materials for high‑precision oxygen isotope microanalysis.