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Abstract

Accurate analyses by Secondary Ion Mass Spectrometry (SIMS) require the use of matrix-matched reference materials due to instrumental mass fractionation. The goal of this data publication is to report a first SIMS homogeneity test of experimentally produced basaltic glasses (Shishkina et al. 2010, Shishkina 2012) to evaluate their potential use as internal reference materials (RMs) for quantification of H2O and CO2 in the GFZ SIMS laboratory. These samples were originally prepared to shed light on magma storage and pre-eruptive conditions as well as degassing paths of natural basaltic systems. The GFZ SIMS laboratory has mm-size chips of 13 samples in total mounted in the centre of an epoxy disc with a diameter of 25.4 mm. All analysed basaltic glasses are relatively homogeneous at the microscale, with relative standard deviations (1RSD) of 1.9 to 15.1% for C/Si, 1.6 to 6.5% for OH/Si and 0.4 to 4.5% for SiH/Si. While the relationship of measured C/Si ratios versus nominal CO2/SiO2 concentrations is described by a linear function, the relationships of OH/Si and SiH/Si ratios versus nominal H2O/SiO2 concentrations are described by quadratic functions. Eight samples (M2, M5, M6, M30, M39, M43, M70 and N72) can be used to quantify CO2 by SIMS in basaltic glasses with concentrations up to 5943 µg/g. Nine samples (M2, M5, M22, M30, M39, M43, M49, M70 and N72) can be used to quantify H2O in basaltic glasses with concentrations up to 8.81 wt.%. We note that H2O quantifications using the measured SiH/Si ratios are less accurate than those using the OH/Si ratios, hence we recommend using the latter. Measured backgrounds in the blank glass N72 were ca. 10 µg/g for CO2 and 0.06 wt.% for H2O. The relative uncertainties on CO2 and H2O calculated values (i.e., SIMS bias) are 12 to 25% (CO2 < 1000 µg/g) and ca. 13% (H2O < 1 wt.%). At higher concentrations (CO2 > 3000 µg/g and H2O > 1 wt.%), uncertainties are lower (2 to 5% for carbon and < 6% for water). In addition to the SIMS data, we provide the synthesis conditions, chemical compositional data, and bulk H2O and CO2 contents of the investigated basaltic glasses.