The glass compositions of major elements have been analyzed at INGV-OE with Zeiss LEO-1430 scanning electron microscope, equipped with an INCA ENERGY Oxford Instruments EDS micro-analytical system (SEM-EDS). Analytical conditions are 20 keV of acceleration tension, 1200 nA of beam current and XPP data reduction routine. In order to minimize alkalis loss during analysis, a square raster of 10 microns is used. The accuracy of our measurements has been checked through replicate analyses of the international standard VG-2 Glass basaltic, USNM 111240/52 (Jarosewich et al., 1980). The precision, expressed as relative standard deviation, is less than 1% for SiO2, Al2O3, FeO, MgO and CaO and less than 3% for TiO2, MnO, Na2O, K2O and P2O5 (Miraglia, 2012).
The analyses have been performed in groundmass glass containing less than 15% microlites. Each measure is the average of 10 to 15 analyses.