抄録
The δ17O and δ18O values of some international silicate reference materials such as NBS-28 quartz, NBS-30 biotite, UWG2 garnet, San Carlos olivine and some mineral separates of terrestrial origin were re-evaluated on the VSMOW-SLAP scale using the CO2-laser fluorination technique. To report their δ18O values on the VSMOW-SLAP scale, the δ17O and δ18O values of O2 directly derived from VSMOW and SLAP were measured using the same preparation line as used for the silicates. Application of the VSMOW-SLAP scale to the above silicate reference samples resulted in the δ18O values of NBS-28 quartz, NBS-30 biotite, UWG2 garnet and San Carlos olivine that are 9.18, 4.88, 5.59 and 5.28‰, respectively. The data form a straight line in the 103 ln(1 + δ17O/103) vs. 103 ln(1 + δ18O/103) plot with a slope of 0.526 ± 0.003 (standard error at 95% confidence limit), but the line for the waters (VSMOW, GISP, SLAP and MSA-6) seems to have a slightly steeper slope of 0.528 ± 0.001, although difference of the slopes is not statistically significant.
