Secondary standards for major element oxide analyses for the geochemical composition of analysed volcanic events from B19, TUNU2013, and RECAP Greenland ice cores and correlating proximal material from Iceland between 750 and 940 CE

Secondary Standards of Cannetto Lami Lava, Lipari and BCR-2Ga for major element oxide tephra glass analyses obtained across the period 750-940 CE. Data was obtained using electron probe micro-analysis (EPMA) at the University of Bern, Switzerland, Queen's University Belfast, UK, and University of Edinburgh, UK.