| OCR Text |
Show Table 4.1. Elements, standards, element concentrations of standard materials, and analytical setup for electron microprobe calibration and analysis. Element (oxide) Element Standard Material Concentration (in oxide wt %) Detection Limit (95% Crystal and Spectral confidence interval)/ Spectrometer Line cases below detection Na2O VG5681 3.75% TAP (1) Kα 0.03/n = 0 MgO Kaersutite 12.9% TAP (1) Kα 0.02/n = 231 (16.7%) Al2O3 Anorthite 35.8% TAP (1) Kα 0.02/n = 0 SiO2VG568 76.71% TAP (1) Kα 0.04/n = 0 K2O VG568 4.89% PET (2) Kα 0.02/n = 0 19.2% PET (2) Kα 0.02/n = 0 5.7% PET (2) Kα 0.03/n = 24 (1.7%) 41.45% LIF (3) Kα 0.04/n = 713 (51.6%) 89.97% LIF (3) Kα 0.04/n = 0 CaOAnorthite TiO2 Kaersutite MnO Spessartine FeO Hematite 1Rhyolitic volcanic glass from the Yellowstone region. Table 4.2. Mean microprobe analyses and actual composition of the rhyolitic volcanic ash standard; data are normalized to 100%. Na2O MgO Al2O3 SiO2 K2 O CaO TiO2 MnO FeO Mean (n=132) 3.46 0.03 12.12 77.73 5.00 0.43 0.09 0.03 1.11 Standard deviation 0.36 0.02 0.30 0.44 0.26 0.05 0.04 0.04 0.10 Actual composition of VG568 standard 3.75 - 12.06 76.71 4.89 0.50 0.12 0.03 1.23 V.4.20 |
